Effects of extra-oral appliances
And
Forces
Prepared by
Dr. Mohammed Alruby
Factors affect extra-oral force
Studies of maxillary protraction force
Results of extra-oral force
Effects of extra-oral appliances
The effects of extra-oral forces on dentofacial structure depend on the following factors:
- Direction of force
- Magnitude of force
- Duration of force
- Growth
- Patient cooperation
1- Direction of force:
Kloehn 1953, Gould 1975, Greenspan 1970, Merrifield and Cross 1970, and Worms et al 1973, all give an adequate description for the direction of force application and their effect on maxillary molar position, tipping, bodily, extrusion, intrusion movement
The direction of force should be adjusted according to the patient needs and objective of treatment as:
- When bodily movement is required, the force should pass through the center of resistance of molars (at the tri-furcation of roots) and the extra-oral tube should be placed gingivally as possible
- When bodily displacement of maxilla is required, the force should pass through the center of maxillary resistance (zygomatic bone)
- When extrusion of molars is required, (in case of deep bite) the force should pass below the center of resistance (below the level of occlusal plane)- cervical headgear is the best choice
- When intrusion is required (open bite cases) the force should pass above the level of occlusal plane
- In occipital headgear, the vector of force may pass through the center of resistance of 1st molar and thus causes: -------------- distal translation of 1st molar
- If the vector of force passes above the center of resistance causing:
a- Distal root torque
b- Mesial crown tipping
c- Intrusion of maxillary 1st molar ---- that, ----- closing the bite and same can occurs in the vertical or high pull headgear
== the direction of force can be determined by adjusting the outer bow in relation to the occlusal plane or center of resistance
== the best method for recording the force direction is the lateral cephalometric radiograph with the appliance in place, then the outer bow is adjusted in relation to the occlusal plane and the center of resistance of tooth or jaw
= in Kloehn’s face bow, the direction of force is 25 – 30 degree below the occlusal plane so that, the vector of force is far away from the center of resistance of 1st molars, thus cervical headgear causes distal tipping and extrusion of 1st molars and open bite
The direction of force depends upon the following variables:
I- Vertical position of the outer bow relative to the center of resistance:
= force applied by oblique headgear passing through the center of resistance will cause translation of the tooth and make intrusion at the same time
= force applied by oblique headgear passing above the occlusal plane
but below the center of resistance will cause:
a- Distal crown tipping, mesial root torque
b- Extrusion of mesial marginal ri
This document discusses various aspects of orthodontic anchorage. It defines anchorage and provides classifications including according to the manner of force application, the jaws involved, and the site of anchorage. Biological aspects are covered such as factors affecting an individual tooth's anchorage value like the number, shape, and length of roots. Mechanical aspects include using force couples to restrict unwanted tooth movement. Different anchorage reinforcement techniques are presented such as extraoral appliances, implants, and temporary anchorage devices.
1. Face masks apply heavy orthopedic forces over 400g to effect changes in skeletal structures.
2. They derive anchorage from both the chin and forehead to distribute forces over a large area and prevent excessive force on growth centers.
3. Forces of around 450g per side for 12-14 hours per day are recommended to protract the maxilla forward and downward around 15-20 degrees to the occlusal plane.
Anchorage refers to resistance to unwanted tooth movement when orthodontic forces are applied. There are various sources of anchorage, including teeth, bone, implants, and extraoral appliances. Anchorage preparation involves incorporating multiple teeth, using reinforcing appliances, and positioning teeth at right angles to forces to maximize resistance. Proper anchorage planning considers the anchorage demand based on the number and type of teeth to be moved and duration of treatment.
The document discusses different types of headgears used in orthodontic treatment including cervical headgear, high-pull headgear, combination headgear, and headgear attached to the lower jaw. It explains how the position of the outer bow relative to the center of resistance and line of force determines the direction of tooth movement and effects on the occlusal plane. Intrusive, extrusive, clockwise, and counterclockwise moments can be created by adjusting the outer bow position. The timing and indications for different headgear types are also covered.
This document discusses different types of orthodontic forces including continuous, interrupted, and intermittent forces. Continuous forces maintain a constant force level over time while interrupted forces gradually decrease. Intermittent forces are applied and removed periodically. Interrupted and intermittent forces allow tissue remodeling between applications. One-couple and two-couple orthodontic appliance systems are also described. Various orthodontic mechanics are outlined, including intrusion arches, V-bends, and lingual arches. Posterior crossbite correction using appliances like quad helix or expansion plates is also mentioned.
This document provides an overview of orthopedic appliances used to modify maxillary and mandibular growth. It discusses the principles, types (e.g. headgear, facemask), biomechanics, and clinical applications of these extraoral appliances. Key points covered include the magnitudes, durations, and directions of optimal orthopedic forces; the use of headgears like cervical pull, high pull, and combinations; and the goals of growth modification to alter skeletal relationships and avoid surgery.
Intrusion PEREPERD BY DR.ABDULGHANI ALMOHAYA ,ALHADDAD.pptxAbdulghaniAlmohaya
The document discusses intrusion, which refers to the apical movement of a tooth's geometric center in relation to the occlusal plane or the tooth's long axis. Intrusion can be used to correct deep overbites by moving anterior teeth vertically downward. True intrusion is achieved by applying a single intrusive force through the tooth's center of resistance. Several appliances can provide intrusive forces, including utility arches, tip-back springs, and segmented arches. Proper biomechanics must be followed, such as applying light, constant forces and positioning the force vector through the tooth's center of resistance and parallel to its long axis.
Extra-oral forces
And
Appliances
Prepared by:
Dr. Mohammed Alruby
Definition
Philosophy
History and development
Classification of extra-oral forces
Advantages of extra-oral forces
Disadvantages of extra-oral forces
Uses of extra-oral forces
Headgear
Appliance enhanced the action of headgear
Protraction appliances
Types of reversed headgear
Chin cup appliance
Orthopedic correction of class III
Orthopedic correction of open bite
Orthopedic correction of class II
Retention after orthopedic correction
Definition
It is a force derived from an extra-oral appliance that uses the forehead, the top of the head or the back of the neck as anchorage to apply forces to the dental or basal arch. It may be orthodontic force or orthopedic force to move the dentition, or restrict or redirect the growth respectively.
Philosophy:
The philosophy beyond the use of extra-oral force is based upon the old concept that, (the application of appreciable amount of force against the growing bone con modify or alter the direction of bone growth and consequently alter the shape and position of the bone
= the well-known best examples are the induced skull deformation in Colombia –India and feet deformation in Chinese girls
History and development:
Appliances resembling chin cups have been in use since the early 1800's. According to Graber, the early attempts with the chin cup were not successful because of incomplete knowledge of mandibular and facial growth, its use on non-growing patients, and an inadequate understanding of the forces generated by the chin cup.
1802: Cellier and Josef Fox in 1803, utilized chin caps in combination with bite blocks to correct the “underslung chin”
1866: Norman Kingsley introduced extra-oral head cap anchorage or force for maxillary distal movement
1880: Kingsley described an appliance that could influence the position of the dentition in upper jaw with the aid of extra-oral forces
1887: E.H.Angle recommended the use of occipital bandage in treatment of maxillary protrusion
1904: Jackson was first describing the facial mask
1892: headgear appliance was originally designed by Kingsley
1920: Angle and his followers were convinced that class II and class III elastics not only moved teeth but cause a significant skeletal changes: stimulate growth of one and restrain growth for the other so we not need to use any extra-oral force just wait until permanent dentition is completed
1923: Case recommend the use of extra-oral force against maxilla in treatment of class II and class I maxillary protrusion
1947: Kleohn, presented his treatment results with cervical neck strap, subsequent to this report, many other variation of the headgear appliance were presented
1960: Delaire facemask
Classification of extra-oral force appliances according to uses
The extra-oral pull is generally applied bilaterally, for three main purposes:
(1) as a restraining force
(2)
This document discusses various aspects of orthodontic anchorage. It defines anchorage and provides classifications including according to the manner of force application, the jaws involved, and the site of anchorage. Biological aspects are covered such as factors affecting an individual tooth's anchorage value like the number, shape, and length of roots. Mechanical aspects include using force couples to restrict unwanted tooth movement. Different anchorage reinforcement techniques are presented such as extraoral appliances, implants, and temporary anchorage devices.
1. Face masks apply heavy orthopedic forces over 400g to effect changes in skeletal structures.
2. They derive anchorage from both the chin and forehead to distribute forces over a large area and prevent excessive force on growth centers.
3. Forces of around 450g per side for 12-14 hours per day are recommended to protract the maxilla forward and downward around 15-20 degrees to the occlusal plane.
Anchorage refers to resistance to unwanted tooth movement when orthodontic forces are applied. There are various sources of anchorage, including teeth, bone, implants, and extraoral appliances. Anchorage preparation involves incorporating multiple teeth, using reinforcing appliances, and positioning teeth at right angles to forces to maximize resistance. Proper anchorage planning considers the anchorage demand based on the number and type of teeth to be moved and duration of treatment.
The document discusses different types of headgears used in orthodontic treatment including cervical headgear, high-pull headgear, combination headgear, and headgear attached to the lower jaw. It explains how the position of the outer bow relative to the center of resistance and line of force determines the direction of tooth movement and effects on the occlusal plane. Intrusive, extrusive, clockwise, and counterclockwise moments can be created by adjusting the outer bow position. The timing and indications for different headgear types are also covered.
This document discusses different types of orthodontic forces including continuous, interrupted, and intermittent forces. Continuous forces maintain a constant force level over time while interrupted forces gradually decrease. Intermittent forces are applied and removed periodically. Interrupted and intermittent forces allow tissue remodeling between applications. One-couple and two-couple orthodontic appliance systems are also described. Various orthodontic mechanics are outlined, including intrusion arches, V-bends, and lingual arches. Posterior crossbite correction using appliances like quad helix or expansion plates is also mentioned.
This document provides an overview of orthopedic appliances used to modify maxillary and mandibular growth. It discusses the principles, types (e.g. headgear, facemask), biomechanics, and clinical applications of these extraoral appliances. Key points covered include the magnitudes, durations, and directions of optimal orthopedic forces; the use of headgears like cervical pull, high pull, and combinations; and the goals of growth modification to alter skeletal relationships and avoid surgery.
Intrusion PEREPERD BY DR.ABDULGHANI ALMOHAYA ,ALHADDAD.pptxAbdulghaniAlmohaya
The document discusses intrusion, which refers to the apical movement of a tooth's geometric center in relation to the occlusal plane or the tooth's long axis. Intrusion can be used to correct deep overbites by moving anterior teeth vertically downward. True intrusion is achieved by applying a single intrusive force through the tooth's center of resistance. Several appliances can provide intrusive forces, including utility arches, tip-back springs, and segmented arches. Proper biomechanics must be followed, such as applying light, constant forces and positioning the force vector through the tooth's center of resistance and parallel to its long axis.
Extra-oral forces
And
Appliances
Prepared by:
Dr. Mohammed Alruby
Definition
Philosophy
History and development
Classification of extra-oral forces
Advantages of extra-oral forces
Disadvantages of extra-oral forces
Uses of extra-oral forces
Headgear
Appliance enhanced the action of headgear
Protraction appliances
Types of reversed headgear
Chin cup appliance
Orthopedic correction of class III
Orthopedic correction of open bite
Orthopedic correction of class II
Retention after orthopedic correction
Definition
It is a force derived from an extra-oral appliance that uses the forehead, the top of the head or the back of the neck as anchorage to apply forces to the dental or basal arch. It may be orthodontic force or orthopedic force to move the dentition, or restrict or redirect the growth respectively.
Philosophy:
The philosophy beyond the use of extra-oral force is based upon the old concept that, (the application of appreciable amount of force against the growing bone con modify or alter the direction of bone growth and consequently alter the shape and position of the bone
= the well-known best examples are the induced skull deformation in Colombia –India and feet deformation in Chinese girls
History and development:
Appliances resembling chin cups have been in use since the early 1800's. According to Graber, the early attempts with the chin cup were not successful because of incomplete knowledge of mandibular and facial growth, its use on non-growing patients, and an inadequate understanding of the forces generated by the chin cup.
1802: Cellier and Josef Fox in 1803, utilized chin caps in combination with bite blocks to correct the “underslung chin”
1866: Norman Kingsley introduced extra-oral head cap anchorage or force for maxillary distal movement
1880: Kingsley described an appliance that could influence the position of the dentition in upper jaw with the aid of extra-oral forces
1887: E.H.Angle recommended the use of occipital bandage in treatment of maxillary protrusion
1904: Jackson was first describing the facial mask
1892: headgear appliance was originally designed by Kingsley
1920: Angle and his followers were convinced that class II and class III elastics not only moved teeth but cause a significant skeletal changes: stimulate growth of one and restrain growth for the other so we not need to use any extra-oral force just wait until permanent dentition is completed
1923: Case recommend the use of extra-oral force against maxilla in treatment of class II and class I maxillary protrusion
1947: Kleohn, presented his treatment results with cervical neck strap, subsequent to this report, many other variation of the headgear appliance were presented
1960: Delaire facemask
Classification of extra-oral force appliances according to uses
The extra-oral pull is generally applied bilaterally, for three main purposes:
(1) as a restraining force
(2)
differences between natural tooth periodontium and implant bone connection, biomechanics of implants, implant protected occlusion , occlusal principles for single tooth implant prosthetics and implant supported prosthesis on edentulous arch, shortened arch concept, therapeutic occlusion
The twin block appliance was developed in 1977 to treat a young patient with a Class II malocclusion caused by luxation of an upper central incisor. It consists of simple bite blocks with inclined planes at 70 degrees to apply forward and downward force on the mandible. The twin block uses natural muscle forces to encourage favorable skeletal and dental changes. It can be used to treat a variety of malocclusions in both growing and adult patients. Advancements in design have improved function, retention, and patient comfort.
This document discusses the effects of orthopedic forces on the skeletal bases and how they can influence bone growth and shape. It provides examples of how forces have been used to induce deformations in different cultures. While the total bone volume remains constant, orthopedic forces can modify the direction of bone growth. Various studies are cited showing how forces can affect different areas like the cranial base, palate, maxilla, and mandible. Both anterior and posterior forces on the maxilla and mandible are discussed. The document concludes that orthopedic forces can inhibit, influence, or modify anteroposterior and vertical maxillary growth as well as affect mandibular positioning and morphology.
1. Biomechanics is the study of movement in biological systems and explains the mechanisms of orthodontic appliances and force systems used for tooth movement.
2. Understanding biomechanical principles allows orthodontists to design treatment plans, select appliances, and move teeth efficiently with minimal damage.
3. The three laws of motion described by Newton - inertia, acceleration, and action/reaction - are important biomechanical concepts for orthodontists to understand to improve treatment outcomes.
There are 3 main types of orthopedic appliances used to modify maxillary or mandibular growth: headgear, face masks, and chin cups. Headgears apply distal force to the maxilla via hooks on a facebow attached to maxillary molars. Proper force magnitude, direction (through the center of resistance), and duration are important to achieve skeletal changes. Face masks apply anterior force to the maxilla using elastic bands from a chin cup and/or forehead band. They are used to correct retrognathic maxillas. Chin cups provide anchorage for elastic traction from a reverse-pull face mask to protract the maxilla.
This document discusses anchorage in orthodontic treatment. It defines anchorage as the resistance of teeth to movement when a force is applied. Maintaining adequate anchorage is crucial to orthodontic success. The document outlines many factors to consider when selecting anchorage, such as tooth morphology, bone density, and facial muscles. It provides tips for reinforcing anchorage, including using extraoral forces, transpalatal arches, and osseointegrated implants. Maintaining control of unwanted tooth movement during space closure is also discussed.
Techniques for anchorage control in lingual orthodonticsParag Deshmukh
various techniques used in lingual orthodontics for anchorage control are described here.. and various cases of lingual orthodontics in which different techniques were used for anchorage control are discussed here..
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
00919248678078
1. Mechanical forces produced by orthopedic appliances range from 25-500 grams and are measured both directly and indirectly through electromyography. Forces are produced by functional appliances stretching jaw muscles.
2. Headgear applies 350-450 grams of retroactive force to the maxilla to restrict forward growth. Facemasks apply around 450 grams of anterior force at a 27.5 degree angle for orthopedic effects.
3. Rapid maxillary expanders apply 2-10 pounds of transverse force to the maxilla with the jackscrew placed close to the center of resistance for optimal bodily movement effects. Younger patients dissipate forces faster than older patients.
This document provides an overview of orthodontics and orthodontic tooth movement. It defines orthodontics as the specialty concerned with treatment and management of malocclusion. Orthodontic tooth movement results from forces delivered by fixed or removable appliances and occurs through the periodontal ligament in response to these mechanical forces. Proper application of biomechanical principles can improve treatment efficiency. Different types of tooth movement like tipping, translation, and rotation are discussed along with optimal force levels and durations. Factors like wire properties, bracket size and material are also covered.
Definitions
Properties of force
Center of mass, gravity and resistance
Moment
Natural- mechanical force interaction
Description of mechanical forces
Force magnitude
Duration of force
Classification of therapeutically induced force
Orthodontic force system (law and mechanics)
Two couple system
Symmetric and a symmetric bends
Lingual arch as two couple system
Scientific rationale and biomechanics in implantsMurtaza Kaderi
This document discusses the scientific rationale and biomechanics related to dental implants. It defines biomechanics as the relationship between biological behavior of oral structures and the physical influences of dental restorations. The document outlines different types of biomechanics and discusses various biomechanical concepts including forces, stresses, strains and how these impact dental implants and surrounding bone tissue. It also examines factors that influence loading on implants like force magnitude, direction, duration and position in the dental arch.
Orthodontic tooth movement involves applying precise mechanical forces to the teeth to induce biological responses in the periodontal ligament that result in tooth movement. The proper application of biomechanical principles is necessary to control orthodontic treatment and increase efficiency. Optimal forces are light and continuous, applying just enough stress to stimulate cellular activity without damaging blood vessels in the periodontal ligament. Different force systems and levels can be used to produce various types of tooth movement, such as tipping, translation, rotation, and intrusion/extrusion.
1) Mandibular growth rotation (MGR) refers to the complex rotational movements of the mandible that occur during growth due to condylar growth and functional remodeling. MGR can be forward/upward or backward/downward depending on the direction.
2) MGR is influenced by factors like condylar growth, occlusal relationships, and soft tissue influences. It is important to consider a patient's pattern of MGR during treatment planning to determine if extrusive or intrusive mechanics are needed.
3) Forward MGR can contribute to the development of a deep bite skeletal pattern and late lower incisor crowding. Backward MGR can increase lower anterior facial height and cause an
This document discusses different types of anchorage in orthodontics. Anchorage is defined as the resistance to tooth movement provided by anatomical units. There are different classifications of anchorage based on the manner of force application, location, and number of teeth providing resistance. Intra-oral sources include teeth and bone, while extra-oral includes occipital bone and muscles. Anchorage requirements depend on factors like number of teeth moving, type of movement, treatment duration, and occlusal interlock. Anchorage loss can be prevented by reinforcing the anchorage unit, subdividing tooth movement, using tipping movements, controlling forces, and using temporary skeletal anchorage.
This document discusses Bioprogressive Therapy, an orthodontic treatment approach. It covers the principles of BPT including using a systems approach to diagnosis and treatment planning. Forces used in BPT aim to keep roots in vascular bone and apply light continuous forces. The role of orthopedics in manipulating growth is also discussed. Mixed dentition treatment objectives include resolving functional and arch length issues. Lower utility arches are used to upright molars, advance incisors, and direct segmental movements.
This document discusses the basic principles of biomechanics as they relate to orthodontic tooth movement. It defines concepts like force, moment, and center of resistance. It describes different types of tooth movements including tipping, bodily movement, root movement, and rotation. It explains how manipulating the moment-to-force ratio through altering force application points or using countermoments can control the type of tooth movement. Design considerations for appliances to deliver optimal force magnitudes and constancy are also covered, such as varying wire cross-section, interbracket distance, incorporating loops, and using memory alloys.
This document discusses the etiology and management of trauma, specifically maxillofacial trauma. It begins by outlining the leading causes of facial trauma as being motor vehicle accidents and discusses prevention efforts. It then covers fracture patterns from different forces and mechanisms of injury. The document emphasizes the importance of airway management in trauma patients, outlining the ABCDE approach and techniques for airway control in maxillofacial trauma cases such as intubation, tongue sutures, or tracheostomy. It stresses establishing the airway as the top priority in initial trauma management.
=== airway and craniofacial pattern
=== muscle and craniofacial pattern
=== tongue and anterior open bite
=== thumb sucking
=== failure of eruption
=== trauma stability
=== genetics
Treatment:
Thumb sucking
Tongue thrust
Macroglossia
Airway obstruction
Incisor intrusion
Growing patient
Non growing patient
** bonding to second molars
** esthetics and open bite
** ortho-gnathic correction
Definition
Types of rotation
Etiology of rotation
Winging and counter winging rotation
Advantages of derotation
Biomechanics of rotation correction
Methods of correction rotation
Management of molar derotation
Retention of rotated tooth
Methods to prevent relapse
Active retention
Torque when, where, how?
Importance of torque
Biomechanics in torque
Torque expression in slot 0.018 and 0.022
Expression of torque
Mode of ligation and torque
Types of torque
- Passive
- Active
Factors affect torque
Torque with different appliances
Torque in base and face
Torque prescription in different techniques
Class II malocclusion and torque
Torque control in different treatment steps
Differential torque
Torque clearance
Intrusion and torque
Torque and intra-oral elastics
More Related Content
Similar to effects of extra-oral appliances and forces.docx
differences between natural tooth periodontium and implant bone connection, biomechanics of implants, implant protected occlusion , occlusal principles for single tooth implant prosthetics and implant supported prosthesis on edentulous arch, shortened arch concept, therapeutic occlusion
The twin block appliance was developed in 1977 to treat a young patient with a Class II malocclusion caused by luxation of an upper central incisor. It consists of simple bite blocks with inclined planes at 70 degrees to apply forward and downward force on the mandible. The twin block uses natural muscle forces to encourage favorable skeletal and dental changes. It can be used to treat a variety of malocclusions in both growing and adult patients. Advancements in design have improved function, retention, and patient comfort.
This document discusses the effects of orthopedic forces on the skeletal bases and how they can influence bone growth and shape. It provides examples of how forces have been used to induce deformations in different cultures. While the total bone volume remains constant, orthopedic forces can modify the direction of bone growth. Various studies are cited showing how forces can affect different areas like the cranial base, palate, maxilla, and mandible. Both anterior and posterior forces on the maxilla and mandible are discussed. The document concludes that orthopedic forces can inhibit, influence, or modify anteroposterior and vertical maxillary growth as well as affect mandibular positioning and morphology.
1. Biomechanics is the study of movement in biological systems and explains the mechanisms of orthodontic appliances and force systems used for tooth movement.
2. Understanding biomechanical principles allows orthodontists to design treatment plans, select appliances, and move teeth efficiently with minimal damage.
3. The three laws of motion described by Newton - inertia, acceleration, and action/reaction - are important biomechanical concepts for orthodontists to understand to improve treatment outcomes.
There are 3 main types of orthopedic appliances used to modify maxillary or mandibular growth: headgear, face masks, and chin cups. Headgears apply distal force to the maxilla via hooks on a facebow attached to maxillary molars. Proper force magnitude, direction (through the center of resistance), and duration are important to achieve skeletal changes. Face masks apply anterior force to the maxilla using elastic bands from a chin cup and/or forehead band. They are used to correct retrognathic maxillas. Chin cups provide anchorage for elastic traction from a reverse-pull face mask to protract the maxilla.
This document discusses anchorage in orthodontic treatment. It defines anchorage as the resistance of teeth to movement when a force is applied. Maintaining adequate anchorage is crucial to orthodontic success. The document outlines many factors to consider when selecting anchorage, such as tooth morphology, bone density, and facial muscles. It provides tips for reinforcing anchorage, including using extraoral forces, transpalatal arches, and osseointegrated implants. Maintaining control of unwanted tooth movement during space closure is also discussed.
Techniques for anchorage control in lingual orthodonticsParag Deshmukh
various techniques used in lingual orthodontics for anchorage control are described here.. and various cases of lingual orthodontics in which different techniques were used for anchorage control are discussed here..
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
00919248678078
1. Mechanical forces produced by orthopedic appliances range from 25-500 grams and are measured both directly and indirectly through electromyography. Forces are produced by functional appliances stretching jaw muscles.
2. Headgear applies 350-450 grams of retroactive force to the maxilla to restrict forward growth. Facemasks apply around 450 grams of anterior force at a 27.5 degree angle for orthopedic effects.
3. Rapid maxillary expanders apply 2-10 pounds of transverse force to the maxilla with the jackscrew placed close to the center of resistance for optimal bodily movement effects. Younger patients dissipate forces faster than older patients.
This document provides an overview of orthodontics and orthodontic tooth movement. It defines orthodontics as the specialty concerned with treatment and management of malocclusion. Orthodontic tooth movement results from forces delivered by fixed or removable appliances and occurs through the periodontal ligament in response to these mechanical forces. Proper application of biomechanical principles can improve treatment efficiency. Different types of tooth movement like tipping, translation, and rotation are discussed along with optimal force levels and durations. Factors like wire properties, bracket size and material are also covered.
Definitions
Properties of force
Center of mass, gravity and resistance
Moment
Natural- mechanical force interaction
Description of mechanical forces
Force magnitude
Duration of force
Classification of therapeutically induced force
Orthodontic force system (law and mechanics)
Two couple system
Symmetric and a symmetric bends
Lingual arch as two couple system
Scientific rationale and biomechanics in implantsMurtaza Kaderi
This document discusses the scientific rationale and biomechanics related to dental implants. It defines biomechanics as the relationship between biological behavior of oral structures and the physical influences of dental restorations. The document outlines different types of biomechanics and discusses various biomechanical concepts including forces, stresses, strains and how these impact dental implants and surrounding bone tissue. It also examines factors that influence loading on implants like force magnitude, direction, duration and position in the dental arch.
Orthodontic tooth movement involves applying precise mechanical forces to the teeth to induce biological responses in the periodontal ligament that result in tooth movement. The proper application of biomechanical principles is necessary to control orthodontic treatment and increase efficiency. Optimal forces are light and continuous, applying just enough stress to stimulate cellular activity without damaging blood vessels in the periodontal ligament. Different force systems and levels can be used to produce various types of tooth movement, such as tipping, translation, rotation, and intrusion/extrusion.
1) Mandibular growth rotation (MGR) refers to the complex rotational movements of the mandible that occur during growth due to condylar growth and functional remodeling. MGR can be forward/upward or backward/downward depending on the direction.
2) MGR is influenced by factors like condylar growth, occlusal relationships, and soft tissue influences. It is important to consider a patient's pattern of MGR during treatment planning to determine if extrusive or intrusive mechanics are needed.
3) Forward MGR can contribute to the development of a deep bite skeletal pattern and late lower incisor crowding. Backward MGR can increase lower anterior facial height and cause an
This document discusses different types of anchorage in orthodontics. Anchorage is defined as the resistance to tooth movement provided by anatomical units. There are different classifications of anchorage based on the manner of force application, location, and number of teeth providing resistance. Intra-oral sources include teeth and bone, while extra-oral includes occipital bone and muscles. Anchorage requirements depend on factors like number of teeth moving, type of movement, treatment duration, and occlusal interlock. Anchorage loss can be prevented by reinforcing the anchorage unit, subdividing tooth movement, using tipping movements, controlling forces, and using temporary skeletal anchorage.
This document discusses Bioprogressive Therapy, an orthodontic treatment approach. It covers the principles of BPT including using a systems approach to diagnosis and treatment planning. Forces used in BPT aim to keep roots in vascular bone and apply light continuous forces. The role of orthopedics in manipulating growth is also discussed. Mixed dentition treatment objectives include resolving functional and arch length issues. Lower utility arches are used to upright molars, advance incisors, and direct segmental movements.
This document discusses the basic principles of biomechanics as they relate to orthodontic tooth movement. It defines concepts like force, moment, and center of resistance. It describes different types of tooth movements including tipping, bodily movement, root movement, and rotation. It explains how manipulating the moment-to-force ratio through altering force application points or using countermoments can control the type of tooth movement. Design considerations for appliances to deliver optimal force magnitudes and constancy are also covered, such as varying wire cross-section, interbracket distance, incorporating loops, and using memory alloys.
This document discusses the etiology and management of trauma, specifically maxillofacial trauma. It begins by outlining the leading causes of facial trauma as being motor vehicle accidents and discusses prevention efforts. It then covers fracture patterns from different forces and mechanisms of injury. The document emphasizes the importance of airway management in trauma patients, outlining the ABCDE approach and techniques for airway control in maxillofacial trauma cases such as intubation, tongue sutures, or tracheostomy. It stresses establishing the airway as the top priority in initial trauma management.
=== airway and craniofacial pattern
=== muscle and craniofacial pattern
=== tongue and anterior open bite
=== thumb sucking
=== failure of eruption
=== trauma stability
=== genetics
Treatment:
Thumb sucking
Tongue thrust
Macroglossia
Airway obstruction
Incisor intrusion
Growing patient
Non growing patient
** bonding to second molars
** esthetics and open bite
** ortho-gnathic correction
Similar to effects of extra-oral appliances and forces.docx (20)
Definition
Types of rotation
Etiology of rotation
Winging and counter winging rotation
Advantages of derotation
Biomechanics of rotation correction
Methods of correction rotation
Management of molar derotation
Retention of rotated tooth
Methods to prevent relapse
Active retention
Torque when, where, how?
Importance of torque
Biomechanics in torque
Torque expression in slot 0.018 and 0.022
Expression of torque
Mode of ligation and torque
Types of torque
- Passive
- Active
Factors affect torque
Torque with different appliances
Torque in base and face
Torque prescription in different techniques
Class II malocclusion and torque
Torque control in different treatment steps
Differential torque
Torque clearance
Intrusion and torque
Torque and intra-oral elastics
Characteristic of light
History
Laser physics and properties
Component of laser
Classification of laser
Biological effect of laser
Laser effect on dental tissues
Laser safety in dental practice
General application of laser
Personal protective equipment
Types of laser intensity in orthodontics
Uses of laser in orthodontics
Effect of laser in orthodontics
Introduction
History
Classification of maxillary fractured Lefort
Special consideration for orthognathic surgery
- Patient selection:
Age of patient
Assessment of patient motivation and expectation
The nature and severity of skeletal dysplasia
Systemic evaluation
- Patient evaluation:
(1) General evaluation
(2) Esthetic evaluation
(3) Functional evaluation
(4) Radiographic evaluation
a- Ceph ---
PA
Lateral: ------ soft and hard
b- Panorama
c- CBCT
d- Periapical
Protocol for basic orthognathic record collection
Treatment planning
- Time of treatment
- Objective of orthodontic treatment
Pre-surgical
Post-surgical
- Sequence of treatment:
Pre-surgical phase
Orthodontic in theatre
Post-surgical treatment
Surgery without orthodontics
Stability and clinical success
complications
Medical glossary
Prepared by:
Dr. Mohammed Alruby
Medical glossary
Aberrancy: occurring or developing away from the normal situation
Acantholysis: loss of coherence between epithelial cells due to degeneration of desmosomes (intercellular bridge) this will lead to the formation of intra-epithelial clefts, vesicle and bullae
Acanthosis: epithelial hyperplasia, mainly of the stratum spinosum, leading to increase thickness of the stratum granulosum due to increased number of cell layers of prickle cells
Achondroplasia: an autosomally inherited disorder characterized by abnormality of conversion cartilage into bone predominantly affecting the epiphyses of long bones, leading to retarded growth at the epiphyses and resulting in dwarfism with short extremities but normal trunk
Acidogenic: referring to organisms capable of producing acid
Aciduric: referring to organisms capable of surviving and metabolizing under highly acidic conditions
Acquired: a term used to describe a condition, habit or other characteristic which is not present at birth, which developed in the individuals by reaction to some environmental factor (to acquire is to obtain)
Agenesis: failure of formation leading to absence of a part or organ
Aglossia: failure of formation leading to absence of the tongue
Agnathia: absence of the jaw, usually the lower jaw, usually accompanied by approximation of the ears
Amyloid: pertaining of starch, having the characteristic of starch. A protein compound of albumin and chondroitin sulphate which resembles starch in appearance and may be pathologically deposited in certain tissues
Anaplasia: atypical differentiation or lack of differentiation of epithelial cells occurring in the malignant disease. Anaplastic cells have large, hyperchromatic, irregularly shaped nuclei and frequently show a typical mitosis.
Aneuploidy: an abnormal number of chromosomes in a nucleus. This usually arise from failure of paired chromosomes or sister chromatids to disjoin at anaphase of cell division
Aneurysm: circumscribed dilatation of an artery
Aneurysmal: relating to an aneurysm. The term applied to a type of cyst that produce bony expansion simulating the expansion of an artery produced by a vascular aneurysm
Angiogenesis: development of blood vessels
Angioma: a swelling or mass due to proliferation with or without dilatation of vascular channels
Anhydrosis: absence of sweating due to absence of sweat glands
Ankyloglossia: tongue tie, usually due to a short lingual frenum or one attached too near the tip of the tongue, may be due to failure of separation of tongue from the floor of the mouth during embryogenesis
Ankylosis: stiffening or fixation of a joint as a result of a disease process
Anodontia: absence of teeth
Anomaly: deviation from the normal, anything structurally unusual or irregular
Antigen: a substance that can induce an antibody response
Antimongoloid slant: an obliquity of the palpebral fissures laterally
Muscles
Part 3
Prepared by
DR. Mohammed Alruby
Development of oropharyngeal function
Neuromuscular regulation of jaw positions and functions
Muscles controlling mandibular postures
- Muscles of mastication
- Submandibular muscles
- Extensor and flexor muscles of neck
Positions of mandible
Some clinical implications
Development of oropharyngeal function
1- Prenatal maturation:
= During prenatal life, the neuromuscular system does not mature evenly, it is not accidentally that the orofacial region matures a head of limb region
= In human fetus, by about the 8 week, generalized uniform reflex movement of entire body can be elicited by tactile stimulation
Diffuse spontaneous movements in response to as yet unidentified stimuli have been observed as early as 9.5 weeks
Localized specific and more peripheral responses cannot be produced before 11 weeks, and at this time, stimulation of the nose-mouth region causes lateral body flexion
By 14 weeks, the movements have become much more individualized. Stimulation of the mouth area, the general bodily movements no longer are seen but instead facial and orbicular muscle response are produced
Stimulation of the upper lip causes the mouth to close and often deglutition occurs
Respiratory movements of the chest and abdomen are seen first at about 16 week
The gag reflex has been demonstrated in human fetus of 18.5 weeks. By 25v weeks, respiration is shallow but may support life for few hours
Stimulation of the mouth at 29 weeks’ menstrual age has elicited sucking through complete suckling and swallowing is not thought to be developed until at least 32 week
2- Neonatal oral functions:
a- The mouth as sensory instrument:
= At birth, the orofacial region is a very active perceptual system, the infant finds the mouth nipple = more tactile than the visual sensation
At birth, the tactile sense already is more highly developed in the lips and mouth than in the fingers
= The neonate’s slobbers, drools, chew his toe, sucks his thumb and discovers the gurgling sounds can be made with his mouth
= oral function of the neonate is guided primarily by local tactile stimuli, particularly those from the lips and anterior part of the tongue
= the posture’s of neonate’s tongue is between the gum pads and often for enough forward to rest between the lips, where it can perform its role of sensory guidance more easily
= the mouth of infant is used for many purpose, the perceptual functions of the tongue, lips, and facial skin are mingled with the sensory function of taste, smell and jaw position.
= the sensitivity of tongue and lips is greater than other area of the body and the sensory guidance for oral functioning, including jaw movements is from remarkably large area
b- Infant suckling and swallowing:
= Infant suckling and swallowing have been the subjects of much research due to the effectiveness of these activities is a good indication of the neurologic ma
Muscles
Part 2
Prepared by:
Dr. Mohammed Alruby
Muscle function and malocclusion
Muscle development and skull form in relation to function
Facial balance, muscle balance, and orthodontic therapy
EMG response of muscles
Myofunctional therapy
Basic concepts of neuromuscular physiology
Muscle function and malocclusion
Muscle function is a factor in shaping the dental arches and is important in maintaining the stability of the teeth following orthodontic treatment
Muscle fibers contract in response to change in electrical potential of its investing membrane, proprioceptors located in the muscles and the periodontal membrane make possible a high degree of accuracy in bringing the teeth in contact
Class II malocclusion:
The muscle function is usually normal in class I malocclusion with the exception of class I Openbite
In class I cases, the teeth are in state of balance with environmental force, although the actual measurements of tongue and lip forces showed that, they are not equal at any area during particular function
Class I openbite:
= Usually caused by thumb sucking, retained infantile tongue swallowing or both, the child begins with finger habits of sufficient intensity and duration to deform the maxillary anterior segment forcing the incisors labially and allowing the tongue to move farther in forward direction
= the tongue continues to thrust instead of entering the transitional phase, a large part of this activity may be compensatory or adaptive to produce anterior seal with lower lip during swallowing
=such activity accentuates the openbite, prevent complete eruption of incisors and increase the overjet to the extent that the lower lip may cushion behind the maxillary incisors during rest and functional movements
- The upper lip become more hypotonic
- The lower lip become hyperactive
- Chin puckering can see with each swallowing
= the hyperactive mentalis muscle, retroclined, imprecate and flatten the mandibular anterior segment
= the tongue drop downward and mouth breathing become a dominate pattern, as the tongue thrust forward, it elongates in shape thus alter the balance with buccinator mechanism resulting in:
- Collapse of posterior segment
- V-shaped palate
- Buccal cross bite
This occurs also as a result of molding effect of the tongue upon the hard palate
Mouth breathing:
Is the good explain for these changes a result of underdeveloped nasopharyngeal structures and subsequently maxillary deficiency
Class II division 1 malocclusion:
= In contrast to class I class II div 1 involve an abnormal muscle function from beginning
= As abnormal muscle function in class II div 1 is a compensatory or adaptive and is secondary to skeletal relationship
= Because of large overjet, there is lack of the lip seal during rest and various functions so, mouth breathing is developed
= Some individuals translate the mandible forward to effect lip seal and to improv
Muscles
Part 1
Prepare by
Dr. Mohammed Alruby
Histology of muscles
Physiology of muscles
Muscles development
Orofacial muscles
- Facial muscles
- Jaw muscles
- Portal muscles
Methods of studying muscles
Muscle changes during growth
Muscle function and facial development
Histology of muscles
The structural and functional unit of the muscles is the muscle fiber
Muscle fiber: elongated cylinder measure about 10 to 80 microns in thickness and from 1 to 15cm in length
= Each muscle fiber contains an acidophilic granular cytoplasm (sarcoplasm) that rich in:
Glycogen, mitochondria, Golgi apparatus, protein (actin, myosin, tropomyosin),
Large number of myofibrils (sarcostyles) which responsible for muscle contraction
= the muscle fiber is covered by thick membrane called (sarcolemma) and surrounded by CT called (endomysium)
= the muscle fibers are coalescing together to form bundles; each bundles are covered by C T septa called perimysium
= the muscle bundles are coalescing together to the whole muscle which is covered by CT fascia called epimysium, these CT contain: blood vessel, lymph vessel, and nerves, that firmly attach the muscle bundles to each other and attach the whole muscle to its tendon
= the myofibrils (sarcostyles)are the contractile units of the muscle, in skeletal muscle they are transversely striated due to presence of dark and light bands
The dark bands are formed of thick myosin filaments rich in Ca, the light bands are formed of thin actine filaments rich in water, there is a pale line in at the center of dark band called (Henesen’s disk), There is dark line at the center of light bands called (Krauses membrane) or Z line
The distance between the two lines called (sarcomere) which is a contraction unit of the muscle.
During the muscle contraction there the Sarcomere is shortened due to sliding of the light bands over the dark bans. The energy required for contraction is derived from transformation of ATP ------ ADP
Physiology of muscles:
Man has 639 muscles, composed of 6 billion muscle fibers, each fiber has 1000 fibrils, which means that there are 6000 billion fibrils at work at one of time or another.
Elasticity: muscle can be stretched behind its original length and return to the original shape after relaxation (normal muscle can be elongated about 6/10 of its length
Contractility: it is the ability of muscle to shorten its length under nerve impulse, this contraction is stimulated by acetyl choline, glycogen is partially oxidized to provides energy and lactic acid that carried away by blood stream
Excessive accumulation of lactic acid can produce fatigue
Isometric contraction: (stretching): the muscle is simply resisting the external forces without actual shortening
Isotonic contraction: there is an actual shortening of the muscle, the strength of isometric contraction is much greater than that of isotonic contraction as the stre
diagnostic aids part 3, photograph and radiograph.docxDr.Mohammed Alruby
Diagnostic Aids
Part 3
{Radiographs and Photographs}
{BMR and EMG}
Prepared by
Dr. Mohammed Alruby
Radiographs
Means: A procedure that uses a type of high-energy radiation called x-rays to take pictures of areas inside the body. X-rays pass through the body onto film or a computer, where the pictures are made
Types:
Intra-oral radiographs:
Periapical radiographs:
It is necessary for any orthodontic diagnosis for the following reasons:
The pattern and amount of root resorption of deciduous teeth
Presence or absence of permanent teeth, their size, shape, position and relative state of development
Congenital absence of teeth or presence of supernumerary teeth
Character of alveolar bone, lamina dura, and periodontal membrane
Morphology and inclination of permanent teeth roots
Pathological oral condition such as thickened periodontal membrane, periapical infection, root fractures, cysts, retained deciduous teeth
Abnormal path of eruption of permanent teeth
Malposition of individual as: rotation, which requires a larger space on the arch
Very useful in mixed dentition analysis
Recognition of exact position of impacted tooth by using method of parallax: that determine whether the unerupted tooth is located labially or palatally. Two periapical radiograph is taken with the film in the same position in each exposure, but the tube is moved in second exposure about 10cm. if the impacted tooth is moved in the same direction as the tube so the tooth is impacted palatally and the reverse is versa.
Bit-wing radiographs:
Is used mainly for detection of proximal cries, but it is of little value in orthodontic diagnosis
Occlusal film:
Occlusal projection is useful to locate the supernumerary teeth at the midline (mesiodens) and to determine accurately the position of impacted maxillary cuspids
Extra-oral radiographs:
Cephalometric radiographs:
Lateral cephalometric radiographs
PA cephalometric radiographs
Lateral oblique cephalogram:
The patient is directed by 45 degree and take the shot
Since dentofacial structure will be superimposed in the true lateral cephalometric projection, the lateral oblique direction is designed to gives a more accurate recording of the actual tooth position in either the left or right buccal segments depending on which side is approximately perpendicular to the central rays
The lateral oblique cephalogram combines most of advantages of the lateral views, intra-oral periapical survey and panoramic radiograph plus a standard cephalometric registration that makes possible measurements of bone size and eruptive movements so it is of particular size in analysis of developing dentition
Submental vertex cephalometric:
Is used to assess mandibular asymmetry in the transverse and anterior-posterior plane. It is an important aid in detecting asymmetry in the symphysis, body, ramus, and condyle of the mandible. In many cases of asymmetry, this view is important for evaluation of mandibular displacemen
Diagnostic Aids
{Study cast, Cast analysis}
Part (2)
Prepared by
Dr. Mohammed Alruby
Study cast
Definition: it is a positive replica of the teeth and their supporting structure, it should be reproducing accurately all the anatomical details of the teeth, alveolar process, mucobuccal folds, palate, frenal attachment as well as the exact relationship of the mandibular to the maxillary dental arch
Good models begin with good impression, orthodontic impression should displace the lips and cheeks, so that, the full depth of mucobuccal sulci is recorded. This over extension of impression is obtained by building up the tray periphery with wax or by using special orthodontic trays
The position of maximum intercuspation should be recorded by getting the patient to bite through softened wax, that is important for:
1- Recording the proper intercuspation specially in cases of poor occlusal fit due to extraction or tongue thrust. So it is wise to check the occlusion in the mouth and compare it to the occluded cast to insure that the model is correctly articulated
2- Trimming of the upper and lower cast together without change in occlusal relationship or fracture of teeth
Occlusal registration of wax bite:
= the position of maximum intercuspation as well as the centric relation must be registered
= a piece of soft wax large enough to cover the occlusal surface of maxillary teeth is shaped to the form of maxillary arch, then gently pressed against the maxillary teeth
= the patient instructed to relax and mandible is guided to most posterior and superior position of condyle within the glenoid fossa, while the teeth come into occlusion
= if there is shifting during closure due to cuspal interference, this mean that the occlusal position is not coincide with centric occlusal position, in this case, in this case two bites are taken one for usual occlusal position, and the other for centric occlusion
Ideal requirements of orthodontic study models:
1- They are symmetrical and pleasing to the eye and so that a symmetrical arch form can be readily recognized
2- The dental occlusion shows by setting the models on their backs
3- Clean, smooth, bubble free, with sharp angles where the cuts meet
4- Glossy in finish.
Trimming of study models:
There are two types of trimming:
a- Angle trimming:
The purpose of angle trimming is to added an appropriate proportional bases to the anatomical portion of dental casts which is important in:
- Registration of centric occlusion by having the posterior and lateral border of both casts on the same plane, so that cast may place on any side without change in its relationship
- Giving an idea about the relationship of the teeth to the alveolar process and basal bone
- Giving harmonizing appearance of the right and left sides of the cast which any a symmetry can be detected
- Detection of occlusion from any side, anterior as well as lateral sides
Principles:
1- The floor of the base is trimmed
diagnostic aids part 1 diagnosis, examination, BMR, EMG.docxDr.Mohammed Alruby
Introduction:
Proper treatment plane depends on prompt diagnosis, good clinician should have a bird’s eyes to first identify the problem and find its etiology
Definitions:
= Grabber and Rackosi: defined diagnosis as:
Recognition and systemic designation of anomalies, the practical synthesis of the finding, permitting therapy to be planned and identification to be determined
=a continuous evaluation process in orthodontics starting right from the first interaction with the patient continuing through different stages till end of treatment and course follow up visits
Goal of orthodontic diagnosis:
Is to produce a comprehensive description of the patient’s problem and then to synthesis the various elements of description into a rational problem list
Diagnostic aids:
Data required for orthodontic diagnosis are derived from routine essential diagnostic aids and also from supplemental aids when needed, Graber categorized the diagnostic aids into essential and supplemental aids
Essential:
- Case history
- Study models
- Certain radiographs: periapical, bite wing, panoramic radiograph
- Facial photographs
- Intra-oral photographs
Supplemental:
- Specialized radiographs: occlusal of maxilla and mandible, lateral cephalogram
- Hand &wrist radiograph
- Electromyography
- Endocrine test
- Basal metabolic rate
Case history:
Complete case history includes all the relevant information derived from the patient and parents and essential for planning
Personal details:
Name:
The patient’s name should be recorded for the purpose of identification and communications
Calling the patient by his/her name not only establishes a good report but also imparts confidence in the patient mind about treatment providers
In case of children, it might help to know their pet problems
Age:
= certain malocclusion occurring during growth period are transient and self-correcting
= growth modification procedures such as functional appliances can be carried out during growth periods
= surgical respective procedures such as orthognathic surgery are best carried out after cessation of growth
= chronological age is important for the maintaining of shedding and eruption time tables as well
Gender:
= recording gender of the patient is important for treatment planning, females are observed to precede males in growth related events such as onset of growth spurt, eruption of the teeth and onset of puberty
= gender may also have a bearing on patient’s compliance toward certain types of orthodontic treatment
Occupation and address:
Occupation of patient / or parents gives an idea about socioeconomic condition which might affect the selection of orthodontic appliances and can give an idea about awareness
Address of patient determine the sociality of the patient and this effect on the treatment because some countries have normally bi-maxillary protrusion and also determine the awareness of patient about treatment and oral hygiene
Patient behavior:
Behavior of patient depend on: patient
Smile: is the most pleasant and wanted expression by each one of us.
Smile: is amused facial expression with the corner of mouth turned up and exposed front teeth
Facial expression, postures of lips, occlusion and arrangement of teeth, buccal corridor, shape of teeth, gingival color, texture, contour and other several aspects constitute component of smile
Most of patients come to us to improve their smiles, the orthodontic studies stress on skeletal structure than soft tissue structure, and the smile still receives relatively little attention
Nature of smile:
1- Posed smile: voluntary, static, sustained, social smile not elicited by an emotion
2- Un-posed smile: spontaneous, involuntary, dynamic, natural, and not sustained characterized by greater lip elevation
Smile types: smile styles:
1- Commissures smile: the corner of the mouth turned upward called Monalisa smile
2- Cuspid smile: the upper lip is elevated, the entire lip rises like a window shade
3- Complex smile: the upper lip moves superiorly as in cuspid smile and lower lip moves inferiorly
Evaluation of posed smile:
variables Normal smile Not good smile
Smile arc Consonant Non consonant
Smile index Average Increased / decreased
Morley’s ratio 75 – 100% (normal) Disturbed
Buccal corridor Average Obliterated / excessive
Smile line Average High / low
Occlusal plane No canting Canting occlusal plane
Important definitions:
Smile arc:
the curvature formed by an imaginary line tangent to the incisal edges of the teeth, modified in varying degree of curvature in relationship to the lower lip
Range: from no curvature to an accentuated curvature was in relation to the lower lip, so quantification differed for each model
Buccal corridor:
the amount of dark space displayed between the facial surfaces of the posterior teeth and the corner of the mouth, calculated as the total dark space on both sides of the mouth as a percentage of the total smile width
Range: from 6% to 26.5 in approximately 0.5% increments
Maxillary gingival display or gummy smile:
The amount of gingival show above the central incisor crown and below the center of the upper lip. Negative number indicate gingival exposure. Positive number indicate tooth overlap by the lip
Range: from 1mm of gingival display (-1) to almost 7mm of tooth coverage for the female models, and approximately 2mm of gingival display (-2) to 6mm tooth coverage for male models
The variation between the models was due to differences in sizes and coordinating the images for different faces
Maxillary midline to face:
The relationship of maxillary dental midline (measured between the central incisors) to the midline of the face, defined by the center of the philtrum and the facial midline
Range: the maxillary midline was moved to the left of the face in approximately 0.25 mm increments. The right and left buccal corridor was maintained throughout the movement of the dentition. The maximum deviation show is 6mm
Maxillary to mandibular mid
orthodontic biology of tooth and supporting structure.docxDr.Mohammed Alruby
The goal is to examine the relationship between orthodontic biomechanics and the underlying biological process
When orthodontic force is applied to the crown of the tooth it is transmitted through the roots to the periodontal ligament and alveolar bone
Histology of supporting structure:
- Periodontal ligament
- Alveolar bone
I- Periodontal ligament:
A- Cellular component:
• Forming cells:
Osteoblast: bone forming cells
Fibroblast: PDL fibers forming cells
Cementoblast: in layer adjacent to the roots
• Resorptive cells:
Osteoblast: large cell rich acid phosphatase enzyme that demineralize the bone and disintegrate of organic matrix
Fibroblast: disintegrate fibers
Cementoblast: resorb cementum
• Progenitor cells: undifferentiated mesenchymal cells UMC: small cells with closed nucleus and little cytoplasm & monocytes
• Epithelial rest of malassez: arise as a result of breakdown of epithelial root sheath at the time of cementogesis
• Defensive cells: as macrophages & mast cells
B- Periodontal fibers:
1- Collagen fibers:
the main bulk of PDL fibers and found in 5 groups:
- Alveolar crest group: from cervix to alveolar crest
- Horizontal group: from cementum to bone horizontally
- Oblique group: the main attachment that run obliquely from cementum to bone in an apical direction
- Apical group: circumscribed the apex and responsible for resistance to rotation
- Inter-radicular group: inter-mediate plexus, observed midway between bone and root
- Supra-alveolar group:
Dento-gingival
Dento-periosteal
Transeptal
Circular
Alveolo-gingival
2- Oxytalan fibers:
Immediate elastic fibers that resist dissolution by acids unlike collagen
Run from cementum or bone to blood vessels
Play a role in supporting the blood vessels against distortion and compressive strain
c- Ground substances:
organic matrix surrounding the PDL elements, it is chemically composed of CHO linked with protein. CHO- protein complex commonly divided into two groups: proteoglycan and glycoprotein
ground substances of periodontal ligament is in a continuous state of remodeling process
d- Neurovascular elements:
myelinated: pain sensation
non-myelinated: blood vessels wall
PDL functions:
- Supportive
- Nutritive
- Remodeling
- Sensory
II- Alveolar bone:
= in human, marrow spaces are rare in the buccal and lingual plates, these spaces decreased with age
= wider spaces are lined with a layer of fenestrated compact bone when PDL fibers are anchor these fibers is called bundle bone
N: B:
= collagen turn over in PDL is higher 4 times than skin and 2 times than gingiva and this due to the forces in PDL is multi-directional takes vertical and horizontal component
= lake of marrow spaces implies that bone resorption takes more time so that the tooth movement in mesial and distal direction occur more than labial and lingual sides
= the resorptive cells increase as the marrow spaces increase
N: B:
The new deposited tissue during tooth migration have 3 stages:
Stage I osteoid:
is the pr
Successful infection prevention program
A successful infection prevention program depends on:
1-Developing standard operating procedures.
2- Evaluating practices and providing feedback to dental health care personnel (DHCP).
3- Routinely documenting adverse outcomes (e.g., occupational exposures to blood) and work-related illnesses in DHCP.
4- Monitoring health care associated infections in patients.
Standard Precautions
Standard Precautions: are the minimum infection prevention practices that apply to all patient care, regardless of suspected or confirmed infection status of the patient, in any setting where health care is delivered. These practices are designed to both protect DHCP and prevent DHCP from spreading infections among patients.
Standard Precautions include:
1- Hand hygiene.
2- Use of personal protective equipment (e.g., gloves, masks, eyewear).
3- Respiratory hygiene / cough etiquette.
4- Sharps safety.
5- Safe injection practices (i.e., aseptic technique for parenteral medications).
6- Sterile instruments and devices.
7- Clean and disinfected environmental surfaces.
Each element of Standard Precautions is described in the following sections. Education and training are critical elements of Standard Precautions, because they help DHCP make appropriate decisions and comply with recommended practices.
1- HAND HYGIENE:
1- Perform hand hygiene.
a. When hands are visibly soiled.
b. After bare hand touching of instruments, equipment, materials, and other objects likely to be contaminated by blood, saliva, or respiratory secretions.
C. Before and after treating each patient.
d. Before putting on gloves and again immediately after removing gloves.
2. Use soap and water when hands are visibly soiled (e.g., blood, body fluids); otherwise, an alcohol-based hand rub may be used.
2- PERSONAL PROTECTIVE EQUIPMENT (PPE):
1- Provide sufficient and appropriate PPE and ensure it is accessible to DHCP.
2- Educate all DHCP on proper selection and use of PPE.
3- Wear gloves whenever there is potential for contact with blood, body fluids, mucous membranes, non-intact skin or contaminated equipment.
a- Do not wear the same pair of gloves for the care of more than one patient.
b- Do not wash gloves. Gloves cannot be reused.
c- Perform hand hygiene immediately after removing gloves.
4- Wear protective clothing that covers skin and personal clothing during procedures or activities where contact with blood, saliva, or OPIM (other potential infectious materials) is anticipated.
5- Wear mouth, nose, and eye protection during procedures that are likely to generate splashes or spattering of blood or other body fluids.
6- Remove PPE before leaving the work area.
3- RESPIRATORY HYGIENE / COUGH ETIQUETTE:
1- Implement measures to contain respiratory secretions in patients and accompanying individuals who have signs and symptoms of a respiratory infection, beginning at point of entry to the facility and conti
The way to infection control in dental clinics
Introduction:
The unique nature of dental procedures, instrumentation and patient care settings require specific strategies directed to the prevention of transmission of diseases among dental health care workers and their patients.
Disease: impairment of normal functioning, manifested by signs and symptoms.
Infection: state produced by an infected agent in or on a suitable host, host may be or may not have signs or symptoms.
Carrier: individual harbors the agent but does not have symptoms (person can infect others).
Factors that allow or aid infection:
= The presence of pathogenic micro-organisms.
= There must be a portal of entry via which the organisms invade and colonize the susceptible host.
Medical history
A thorough medical history should be taken and up-dated at subsequent examinations. Medical history screening is essential in alerting the clinician to medical problems that could, in conjunction with dental treatment, adversely affect the patient.
Protective measures
Protection can be achieved by a combination of immunization procedures, use of barrier techniques and strict adherence to routine infection control procedures.
(a) Immunization:
All dental health care workers are advised to be immunized against HBV unless immunity from natural infection or previous immunization had been documented
(b) Protective coverings:
=Uniforms:
Uniforms should be changed regularly and whenever soiled. Gowns or aprons should be worn during procedures that are likely to cause spattering or splashing of blood.
=Hand protection:
Gloves must be worn for procedures involving contact with blood, saliva or mucous membrane. A new pair of gloves should be used for each patient.
If a gloves damaged, it must be replaced immediately. Hands should be washed thoroughly with a proprietary disinfectant liquid soap prior to and immediately after the use of gloves.
Disposable paper towels are recommended for drying of hands.
Any cuts o abrasions on the hands or wrists should be covered with adhesive waterproof dressings at all times.
=Protective glasses, masks or face shields Protective:
Glasses, masks or face shields should be worn by operators and close-support dental surgery assistants to protect the eyes against the spatter and aerosols which may occur during cavity preparation, scaling and the cleaning of instruments.
(c) Sharp instruments and needles:
Sharp instruments and needle should be handled with great care to prevent unintentional injury. Needles should never be recapped by using both hands indirect contact or by any other technique that involves moving the point of a used needle towards any part of the body. The needle can be recapped by laying the cap on the tray, placing the cap in a re-sheathing device or holding the cap with forceps before guiding the needle into the cap.
(d) First aid and inoculation injuries:
preventive and interceptive for general practitioners.docxDr.Mohammed Alruby
Scope of orthodontics
for general practitioner
Prepared by
Dr. M Alruby
Orthodontics: is a branch of science and art of dentistry dealing with prevention, interception, and correction of positional and dimensional dentofacial abnormalities.
Orthodontic treatment could be divided as follow:
1- Preventive orthodontic treatment.
2- Interceptive orthodontic treatment.
3- Corrective orthodontic treatment. a) Early corrective. b) late corrective.
4- Post. Treatment maintenance or retentive and follow up.
Preventive orthodontics:
It is defined as that phase of orthodontics employed to recognize and eliminate potential irregularities and malposition in the developing dentofacial complex. It is directed toward improving environmental conditions to permit future normal development
N: B: the child as a patient: children will accept orthodontic treatment if the purpose for treatment is explained in a simple terms that they can understand. Information concerning treatment aims and procedures should be given to the child without hesitation and under authority; neither gives him a great attention nor neglect him. Be familiar with the child and give him some sympathy.
Most children at preadolescent age are ready to accept orthodontic treatment if the orthodontist was able to establish a sympathetic relationship with the child. The child must not force to treatment but it is better to postpone treatment until the child feels the needs for treatment.
The adolescent patients: the 15 years old patient frequently consider himself as a man and must has a special management. Adolescent patient may deny that his teeth need correction and warning of the appliances. It is very important to know whether the patient came to the office alone, with friends or forced by his parents.
Preventive orthodontics is a long range approach and it is largely a responsibility of the general dentist. Many of the procedures are common in preventive and interceptive orthodontics but the timing are different.
Preventive procedures are undertaken in anticipation of development of a problem. Interception procedures are undertaken when the problem has already manifested. For extraction of supernumerary teeth before they cause displacement of other teeth is a preventive procedure, while their extraction after the signs of malocclusion have appeared is an interceptive procedure.
Preventive procedures:
A- Pre-dental preventive procedure ( parents education):
Instruct the mother to feed her baby from breast and if the baby to be feed by a bottle, the nipple should be long enough to rest on the anterior third of the tongue. It also should contain a small side opening instead of single large end hole, this allows the milk to flow on the dorsum of the tongue and prevent it from being squeezed directly into the pharynx, by this method the tongue is allowed to function properly during swallowing which is very important in general growth of the jaws, al
Orthodontic Diagnosis
For general practitioners
Prepared by Dr. M Alruby
Orthodontic diagnosis deals with recognition of the various characteristics of the malocclusion. It involves collection of data in a systematic manner to help in identifying the nature and cause of the problem. Comprehensive orthodontic diagnosis is established by use of certain clinical implements called diagnostic aids.
Consideration of general health, appearance and attitude:
The first step in any orthodontic examination is to form a general idea of patient's health status, physical appearance and attitude toward orthodontics.
Case history:
Case history involves eliciting and recording of relevant information from the patient and parents to aid in the overall diagnosis of the case. The information is gathered from the patient and parents.
Personal details:
Name: the patient's name should be recorded for the purpose of communication and identification. Most patients like being called by their name. Addressing the patient by his or her name has a beneficial psychological effect as well. In case of children it is wise to record their pet names.
Age: the patient's chronological age should be recorded. Age consideration helps in diagnosis as well as treatment planning. There are certain modalities that are best carried out during the growing age. Growth modification procedures using functional and orthopedic appliances are carried out during the growth period. Surgical respective procedure is best carried out after the cessation of growth.
** Dental age determination: can be determined by two different methods:
- Stage of eruption of teeth.
- Stage of tooth mineralization on radiograph.
Determination of the dental age from observation has been the only method available for long time. In certain cases however, the accuracy of the method is limited.
When determining the dental age radiographically according to the stage of germination, the degree of development of individual teeth is compared to a fixed scale.
** Skeletal age evaluation: assessment of the skeletal age is often made with the help of a hand radiograph which can be considered the biologic clock. For the analysis of skeletal maturity the stage of mineralization of the carpal bones must be determined thereafter the development of the metacarpal bones and phalanges should be evaluated. For the evaluation of the hand radiograph various indicators regarding the development and maturity are established which occur regularly in a definite sequence during skeletal development.
Sex: the patient sex should be recorded in the case history. This is important in planning treatment, as the timing of growth events such as growth spurts is different in males and females. Females usually precede males in onset of growth spurts, puberty and termination of growth.
Address and occupation: this help in evaluation of socio-economic status of the patients and parents. Some countries
Osteoporosis - Definition , Evaluation and Management .pdfJim Jacob Roy
Osteoporosis is an increasing cause of morbidity among the elderly.
In this document , a brief outline of osteoporosis is given , including the risk factors of osteoporosis fractures , the indications for testing bone mineral density and the management of osteoporosis
Does Over-Masturbation Contribute to Chronic Prostatitis.pptxwalterHu5
In some case, your chronic prostatitis may be related to over-masturbation. Generally, natural medicine Diuretic and Anti-inflammatory Pill can help mee get a cure.
These lecture slides, by Dr Sidra Arshad, offer a quick overview of the physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar lead (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
6. Describe the flow of current around the heart during the cardiac cycle
7. Discuss the placement and polarity of the leads of electrocardiograph
8. Describe the normal electrocardiograms recorded from the limb leads and explain the physiological basis of the different records that are obtained
9. Define mean electrical vector (axis) of the heart and give the normal range
10. Define the mean QRS vector
11. Describe the axes of leads (hexagonal reference system)
12. Comprehend the vectorial analysis of the normal ECG
13. Determine the mean electrical axis of the ventricular QRS and appreciate the mean axis deviation
14. Explain the concepts of current of injury, J point, and their significance
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. Chapter 3, Cardiology Explained, https://www.ncbi.nlm.nih.gov/books/NBK2214/
7. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
share - Lions, tigers, AI and health misinformation, oh my!.pptxTina Purnat
• Pitfalls and pivots needed to use AI effectively in public health
• Evidence-based strategies to address health misinformation effectively
• Building trust with communities online and offline
• Equipping health professionals to address questions, concerns and health misinformation
• Assessing risk and mitigating harm from adverse health narratives in communities, health workforce and health system
Histololgy of Female Reproductive System.pptxAyeshaZaid1
Dive into an in-depth exploration of the histological structure of female reproductive system with this comprehensive lecture. Presented by Dr. Ayesha Irfan, Assistant Professor of Anatomy, this presentation covers the Gross anatomy and functional histology of the female reproductive organs. Ideal for students, educators, and anyone interested in medical science, this lecture provides clear explanations, detailed diagrams, and valuable insights into female reproductive system. Enhance your knowledge and understanding of this essential aspect of human biology.
Adhd Medication Shortage Uk - trinexpharmacy.comreignlana06
The UK is currently facing a Adhd Medication Shortage Uk, which has left many patients and their families grappling with uncertainty and frustration. ADHD, or Attention Deficit Hyperactivity Disorder, is a chronic condition that requires consistent medication to manage effectively. This shortage has highlighted the critical role these medications play in the daily lives of those affected by ADHD. Contact : +1 (747) 209 – 3649 E-mail : sales@trinexpharmacy.com
Vestibulocochlear Nerve by Dr. Rabia Inam Gandapore.pptx
effects of extra-oral appliances and forces.docx
1. 1
Effects of extra-oral appliances Dr. Mohammed Alruby
Effects of extra-oral appliances
And
Forces
Prepared by
Dr. Mohammed Alruby
2. 2
Effects of extra-oral appliances Dr. Mohammed Alruby
Factors affect extra-oral force
Studies of maxillary protraction force
Results of extra-oral force
Effects of extra-oral appliances
3. 3
Effects of extra-oral appliances Dr. Mohammed Alruby
The effects of extra-oral forces on dentofacial structure depend on the following factors:
- Direction of force
- Magnitude of force
- Duration of force
- Growth
- Patient cooperation
1- Direction of force:
Kloehn 1953, Gould 1975, Greenspan 1970, Merrifield and Cross 1970, and Worms et al 1973,
all give an adequate description for the direction of force application and their effect on maxillary
molar position, tipping, bodily, extrusion, intrusion movement
The direction of force should be adjusted according to the patient needs and objective of treatment
as:
- When bodily movement is required, the force should pass through the center of resistance
of molars (at the tri-furcation of roots) and the extra-oral tube should be placed gingivally
as possible
- When bodily displacement of maxilla is required, the force should pass through the center
of maxillary resistance (zygomatic bone)
- When extrusion of molars is required, (in case of deep bite) the force should pass below the
center of resistance (below the level of occlusal plane)- cervical headgear is the best choice
- When intrusion is required (open bite cases) the force should pass above the level of
occlusal plane
- In occipital headgear, the vector of force may pass through the center of resistance of 1st
molar and thus causes: -------------- distal translation of 1st
molar
- If the vector of force passes above the center of resistance causing:
a- Distal root torque
b- Mesial crown tipping
c- Intrusion of maxillary 1st
molar ---- that, ----- closing the bite and same can occurs in
the vertical or high pull headgear
== the direction of force can be determined by adjusting the outer bow in relation to the occlusal
plane or center of resistance
== the best method for recording the force direction is the lateral cephalometric radiograph with
the appliance in place, then the outer bow is adjusted in relation to the occlusal plane and the
center of resistance of tooth or jaw
= in Kloehn’s face bow, the direction of force is 25 – 30 degree below the occlusal plane so that,
the vector of force is far away from the center of resistance of 1st
molars, thus cervical headgear
causes distal tipping and extrusion of 1st
molars and open bite
The direction of force depends upon the following variables:
4. 4
Effects of extra-oral appliances Dr. Mohammed Alruby
I- Vertical position of the outer bow relative to the center of resistance:
= force applied by oblique headgear passing through the center of resistance will cause translation
of the tooth and make intrusion at the same time
= force applied by oblique headgear passing above the occlusal plane
but below the center of resistance will cause:
a- Distal crown tipping, mesial root torque
b- Extrusion of mesial marginal ridge and intrusion of distal marginal ridge --- open bite
= force pass parallel to occlusal plane will produce:
a- More distal crown tipping and less mesial root torque
b- Extrusion
= force applied by cervical headgear pass below the occlusal
plane and away from center of resistance will cause:
a- Distal crown tipping with less root torque
b- Extrusion ------ intrusion
It was noted that the types of movement depend upon the relationship between the vector of force
and center of resistance expressed by the perpendicular distance between line of force and center
of resistance
When the vector of force passes through the center of resistance, the perpendicular distance equal
zero and the teeth will be translated
When the force line passes Coronally to the center of resistance, ----------- the center of rotation
will move apically to the center of resistance that produce:
a- Tipping of crown in one direction
b- Slight tipping of the root in opposite direction
AS: the vector of force moves Coronally, the center of rotation moves apically with consequent:
Increase crown tipping ----- and --- decrease root torque
Until the center of rotation become at the root apex, then the crown tipped without torqueing
N: B:
Kloehn reported that:
a- Placing the outer bow in high position above the center of resistance will causes:
- Mesial crown rotation
- Distal root torque
- Extrusion of distal marginal ridge and intrusion of mesial marginal ridge
b- Placing the outer bow in low level below the occlusal plane will causes:
- Distal crown rotation
- Mesial root torque
- Extrusion of the mesial marginal ridge
c- Placing the outer bow parallel to the occlusal plane will causes:
- Distal crown rotation
- Extrusion
5. 5
Effects of extra-oral appliances Dr. Mohammed Alruby
II- The length of the outer bow:
Gould and Greenspan showed that, the length of outer bow may change the direction of force on
the teeth
Regarding the length of the outer bow, there are 3 possible varieties:
a- Short bow: ending mesial to maxillary molar tubes
b- Long bow: ending distal to molar tubes
c- Medium bow: ending at the level of molar tubes
Effect of short bow:
a- Mesial crown tipping
b- Distal root torque
c- Intrusion of mesial marginal ridge
d- Extrusion of distal marginal ridge
Effect of long bow:
a- Distal crown tipping
b- Mesial root torque
c- Intrusion of distal marginal ridge
d- Extrusion of mesial marginal ridge
Effect of medium bow:
a- Intrusion
b- Distal translation
III- Types of anchorage:
a- Cervical headgear:
The primary vector of force, provides distal and extrusive tooth movement
b- Occipital headgear:
The primary vector of force, provides distal and intrusive tooth movement
c- High- vertical pull or parietal headgear:
The primary vector of force provides an intrusive movement with less distal movement
So that, cervical headgear is the best choice for treatment of class II deep bite
Occipital headgear is the best choice of treatment of class II open bite
Vertical headgear is the best choice for treatment of open bite cases
2- Magnitude of force:
= force between 250 – 400gm / side will cause only dento-alveolar changes and teeth movement
= force about 800gm will be sufficient for anchorage purpose because the extra-oral appliance
worn only half time 12 hour / day, so that, use double amount of force more than delivered by the
intra-oral appliance for successful anchorage
= force more than 800gm / side will sufficient to produce skeletal changes in the dentofacial
complex
Force can be measured by Zebco Fishman gauge or spring scale
It was found that, the magnitude of force depends on the following:
1- Time of treatment: growing bone is more responsive than mature one so that, treatment
during active growth period require less force and produce more pronounced effects
2- Severity of discrepancy: sever discrepancy require more force over long period
6. 6
Effects of extra-oral appliances Dr. Mohammed Alruby
3- The amount of expected growth: if there is enough amount of growth, extra-oral force may
be used in minimum range only for guiding of growth
4- Direction of growth: favorable growth direction requires small amount of force for guiding
while unfavorable growth may require greater amount of force for inhibition or redirection
5- Duration of force application: either less force over longer duration or more forces over
short duration
6- Individual sensitivity and pain threshold: the applied force should not cause pain or
discomfort to the patient
=== force more than 3 pounds will cause soreness of the teeth and cervical region
3- Duration of force application:
There is much variability in the daily wear
The range between the sleeping hours to 24 hours
The range required to produce skeletal changes is 12 -16 hours
4- Growth (time of treatment):
= Treatment should be carried during the active growth periods to take a benefits of pubertal
growth spurt. It starts between 10.5 – 12.5 and lasts 2 years in boys
= By age 13 years, girls become an adult while boys don not reach adulthood until 16 years
Orthopedic force is effective only during active growth period and more particularly during
pubertal spurt. Use of orthopedic force in adult is of little significance
= actually, the maxillary growth ceases early so that, the best results of orthopedic correction on
maxilla can achieved in early age 6 – 9 years
5- Patient cooperation:
The effect of orthopedic force depends to great extent on patient cooperation in wearing the
appliance as instructed
Many failures were found due to lake of patient cooperation to wear the appliance. At the same
time, there is no definite way to detect the patient cooperation
By positive re-enforcement and education, some patients are very responsive to therapy
N: B:
A major negative side effects of maxillary protraction procedure is maxillary dental movement that
detract from skeletal change
Shapiro and Kokich used the ankylosed primary canine as natural implant. With traction against
maxillary arch stabilized by these teeth, they were able to demonstrate approximately 3mm of
maxillary protraction in one year, with minimal dental change
Studies for maxillary protraction
Teuscher 1978 has postulated a center of resistance of maxillary complex lying in the region of the
zygomatico-maxillary suture and suggested that maximum restraint of growth without downward
rotation of ANS could be obtained only by ensuring that the force vector passed anterior to this
center of resistance
Cozzani: SNA angle increased by average of 3.5 degree, SNB angle increased 1.02 degree and the
large changes occurred in patients who were 9 years of age or younger when treatment started
7. 7
Effects of extra-oral appliances Dr. Mohammed Alruby
Rune et al, studied the effect of posterior anterior traction in an 11 year- old boy with maxilla-
nasal dysplasia (retrusion of midface and hypoplasia of ANS). The advancement of maxilla is
0.6mm and this limited response due to insufficient growth capacity of circum-maxillary sutures.
Ishii et al, studied the effect of combined maxillary protraction and chin cup appliance in severe
class III cases, they found:
Pogonion moves backward by 1.68mm and downward by 1.15mm
Point B moved backward by 2.0mm
These changes means that there was a backward displacement and downward and backward
rotation of the mandible by chin cup
Chong and Ive evaluated treatment effects and post treatment changes following class III
malocclusion, they found: that the early correction of class III with maxillary protraction headgear
induces significant skeletal and dental changes
Chen and Lai-ying evaluated sagittal skeletal and dental changes of severe headgear treatment in
unilateral cleft lip and palate.
After 7 months’ treatment with reverse headgear wear:
1- There is a normalization of the sagittal maxilla-mandibular relationship
2- Significant skeletal changes in maxilla and mandible
MacNamara, described technique combining a bonded rapid palatal expansion appliance, with
orthopedic facial mask, the effects include:
1- Forward and downward movement of maxilla
2- Forward and downward movement of maxillary dentition
3- Downward and backward redirection of mandibular growth
4- Lingual tipping of lower anterior teeth
5- Inhibition of mandibular growth
Baik 1995, studied the protraction of maxilla in 60 subjects from 8 – 13 years of age with 47
subjects with RME and 13 with labio-lingual appliance, he concluded the following results:
1- After maxillary protraction, the maxilla and maxillary dentition moved forward and
downward, and mandible and mandibular dentition moved backward and downward
2- Maxilla moved more in RME cases than labio-lingual appliance
3- Palatal plane angle decreased more in case of protraction during palatal expansion than
protraction after palatal expansion
Itoh et al 1985, study the orthopedic effects of maxillary protraction appliance in treatment of
anterior cross bite, and found the following:
1- Parallel protraction forces applied to the molars caused anti-clock wise rotation of the
teeth. force 20 degree downward to occlusal plane decreased the tipping and cause some
extrusion
2- Parallel and downward tractions caused constriction of anterior portion of maxilla
3- Forward pull from molars and 1st
premolars caused anti-clockwise opening rotation of the
palatal plane
Maxillary deficiency is a deficiency not only in width and height but also in depth.
Protraction of maxilla has been found to increase the sagittal depth.
8. 8
Effects of extra-oral appliances Dr. Mohammed Alruby
Haskell and Farman stated that, non-surgical maxillary protraction has ability to displace the A
point anteriorly. The protraction ranges of A point 2.5 -5mm was reported in limited number of
cases. They hypothesized that variation in success of advancing A point can be explained by the
presence or absence of partial patency of the pre-maxillary maxillary suture.
Ricketts has observed the forward movement of point A in response to treatment of class III and
cleft palate cases. The effect of forward traction of maxilla has been documented in unilateral cleft
lip and palate patients by use of implant
The Net results of extra-oral forces
If there is full cooperation in wearing the appliance and the growth is still active, the following
results can occur:
I- Cervical headgear:
a- Face bow:
Dental effects:
- Distalization of molars and bicuspids to class I
- Increase the arch parameters
- Extrusion of molars
- Reduce over bite
- Reduce over jet
Skeletal effects:
- Inhibit the forward growth of maxilla, ANS hold in position
- Posterior displacement of maxilla, ANS and A point moves posteriorly (movement of maxilla
backward 4 – 7mm)
- Upward rotation of maxilla, PNS moves downward and ANS remains in position or moves
upward
- Downward and backward rotation of mandible – due to molars distalization
- Increase lower face height and increase FMA
b- J – hooks:
Dental effects:
- Distalize incisors
- Extrude incisors
- Reduce over jet
- Increase over bite
- Decrease arch parameters
Skeletal effects:
- ANS rotate downward
- ANS held in position or moves distally
- A point moves distally
9. 9
Effects of extra-oral appliances Dr. Mohammed Alruby
II- Oblique headgear:
a- Face bow:
Dental effects:
- Distalize the molars
- Intrude molars
- Reduce over jet
- Increase over bite
- Increase arch parameters
Skeletal effects:
- ANS rotate downward and PNS upward
- Rotate the maxilla downward
- Inhibit the forward growth of maxilla or moves the maxilla posteriorly
- Mandible rotate upward and forward
- Forward position of symphysis
- FMA remain unchanged or reduced
- Decrease lower face height
b- J hooks:
Dental effects:
- Distalize incisors
- Intrude incisors
- Decrease arch parameters
- Decrease over bite
- Decrease over jet
Skeletal effects:
- Prevent forward growth of maxilla, ANS held in position
- Move the maxilla, ANS moves distally and may rotate upward
- A point moves distally
III- High pull or vertical headgear:
a- Face bow:
Dental effects:
- Intrude molars
- Reduce open bite
Skeletal effects:
- Rotate maxilla downward, ANS rotate downward and PNS upward
- Mandible rotate upward and forward with chin moves anteriorly
- FMA remain unchanged or reduced
- Lower face height is decreased
b- J hooks:
Dental effects:
- Intrude incisors
- Reduce over bite
Skeletal effects:
- ANS moves upward
10. 10
Effects of extra-oral appliances Dr. Mohammed Alruby
N: B:
Indication of extra-oral forces:
1- Skeletal class II malocclusion in growing children
2- Skeletal class III malocclusion in growing children
3- Open bite
4- Deep bite
5- Retraction of incisors and canine
6- Distalization of molars
In case of mandibular correction:
The force is directly applied against the mandible using oblique occipital chin cup in correction of
------------- class III and high pull (vertical) chin cup for correction ----- open bite
In case of maxillary correction:
The force is directed against maxilla, through an intra-oral appliance to effect the desired changes,
it used for correction of:
1- Class II skeletal using cervical or occipital headgear according to over bite
2- Excessive over bite or over jet
3- Class III using face mask
N: B:
Advantages of orthopedic correction:
1- Correct the basic skeletal mal-relationships
2- Improve facial esthetics
3- Reduce the time of treatment
4- Reduce need for extraction
5- Rapid correction of over jet and over bite and molar relationship
6- Reduce needs for complex mechanics in treatment and preparation of anchorage
7- Less damaged the periodontium
8- More stable results