This document discusses the etiology and classification of malocclusion. It begins with an introduction to malocclusion and normal occlusion. It then reviews several classifications of the etiology of malocclusion proposed by researchers, including Moyer's, White and Gardiner's, Proffit's, and Graber's classifications. Graber's classification divides etiologies into general factors, such as heredity, congenital defects, environment, and local factors like anomalies in tooth number or shape. The document provides examples to illustrate different etiologies, such as cleft lip and palate and how conditions like fetal pressure or thalidomide exposure can lead to malocclusion.
This document discusses various classifications and causes of malocclusion. It begins by introducing Moyer's classification which categorizes etiology into heredity, development defects, trauma, physical agents, habits, diseases, and malnutrition. White and Gardiner's classification separates causes into dental base abnormalities, pre-eruption abnormalities, and post-eruption abnormalities. Graber's classification divides factors into general factors like heredity, environment, and local factors like anomalies in tooth number. The document then examines specific causes in greater detail such as heredity, congenital defects, environment, anomalies in tooth number including supernumerary teeth and missing teeth.
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.for more details please visit
www.indiandentalacademy.com
This document discusses the etiology of malocclusion. It states that malocclusion results from an interaction of genetic and environmental factors. The etiology can be classified as general factors, local factors, or skeletal and soft tissue factors. General factors include hereditary traits, congenital defects, environmental influences, and habits. Local factors relate to abnormalities in tooth number, size, shape, eruption, and dental caries. Understanding the etiology is important for developing an effective treatment plan and preventing future relapse.
Serial extraction is an interceptive orthodontic procedure that involves the planned extraction of certain primary and permanent teeth in a sequence to guide the erupting permanent teeth into a favorable position. It was first described in 1929 as a way to address arch length deficiencies. The most common methods are Dewel's method, Tweed's method, and Nance method, all of which extract primary teeth first, followed by premolars and canines. Potential problems include anterior crossbites from residual spacing or skeletal discrepancies.
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.for more details please visit
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1. Orthodontic tooth movement occurs through remodeling of the alveolar bone in response to prolonged mechanical forces on teeth. Bone resorbs on the pressure side and forms on the tension side of the periodontal ligament.
2. Physiologic tooth movements include eruption, drift, and minor movements during mastication. Eruption occurs through growth of the root and forces from the periodontal ligament.
3. When forces are within physiologic limits, tooth movement occurs through frontal resorption on the pressure side and bone formation on the tension side. Excessive forces cause hyalinization and undermining resorption.
The document discusses preventive and interceptive orthodontics. Preventive orthodontics aims to preserve normal occlusion and involves procedures like patient education, caries control, space maintenance, and extraction of supernumerary teeth. Interceptive orthodontics is undertaken when a malocclusion has developed and involves procedures like serial extraction to correct developing issues. Serial extraction specifically refers to the planned removal of certain deciduous and permanent teeth to allow other teeth to align normally through physiologic tooth movement into extraction spaces.
This document discusses the etiology and classification of malocclusion. It begins with an introduction to malocclusion and normal occlusion. It then reviews several classifications of the etiology of malocclusion proposed by researchers, including Moyer's, White and Gardiner's, Proffit's, and Graber's classifications. Graber's classification divides etiologies into general factors, such as heredity, congenital defects, environment, and local factors like anomalies in tooth number or shape. The document provides examples to illustrate different etiologies, such as cleft lip and palate and how conditions like fetal pressure or thalidomide exposure can lead to malocclusion.
This document discusses various classifications and causes of malocclusion. It begins by introducing Moyer's classification which categorizes etiology into heredity, development defects, trauma, physical agents, habits, diseases, and malnutrition. White and Gardiner's classification separates causes into dental base abnormalities, pre-eruption abnormalities, and post-eruption abnormalities. Graber's classification divides factors into general factors like heredity, environment, and local factors like anomalies in tooth number. The document then examines specific causes in greater detail such as heredity, congenital defects, environment, anomalies in tooth number including supernumerary teeth and missing teeth.
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.for more details please visit
www.indiandentalacademy.com
This document discusses the etiology of malocclusion. It states that malocclusion results from an interaction of genetic and environmental factors. The etiology can be classified as general factors, local factors, or skeletal and soft tissue factors. General factors include hereditary traits, congenital defects, environmental influences, and habits. Local factors relate to abnormalities in tooth number, size, shape, eruption, and dental caries. Understanding the etiology is important for developing an effective treatment plan and preventing future relapse.
Serial extraction is an interceptive orthodontic procedure that involves the planned extraction of certain primary and permanent teeth in a sequence to guide the erupting permanent teeth into a favorable position. It was first described in 1929 as a way to address arch length deficiencies. The most common methods are Dewel's method, Tweed's method, and Nance method, all of which extract primary teeth first, followed by premolars and canines. Potential problems include anterior crossbites from residual spacing or skeletal discrepancies.
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.for more details please visit
www.indiandentalacademy.com
1. Orthodontic tooth movement occurs through remodeling of the alveolar bone in response to prolonged mechanical forces on teeth. Bone resorbs on the pressure side and forms on the tension side of the periodontal ligament.
2. Physiologic tooth movements include eruption, drift, and minor movements during mastication. Eruption occurs through growth of the root and forces from the periodontal ligament.
3. When forces are within physiologic limits, tooth movement occurs through frontal resorption on the pressure side and bone formation on the tension side. Excessive forces cause hyalinization and undermining resorption.
The document discusses preventive and interceptive orthodontics. Preventive orthodontics aims to preserve normal occlusion and involves procedures like patient education, caries control, space maintenance, and extraction of supernumerary teeth. Interceptive orthodontics is undertaken when a malocclusion has developed and involves procedures like serial extraction to correct developing issues. Serial extraction specifically refers to the planned removal of certain deciduous and permanent teeth to allow other teeth to align normally through physiologic tooth movement into extraction spaces.
hereditary factors etiology of malocclusionParag Deshmukh
This document discusses various classifications of malocclusion causes and the role of heredity in malocclusion. It provides an overview of White and Gardiner's, Moyer's, Graber's, Houston's and Proffit's classifications of etiological factors. Genetic factors that can influence malocclusion include tooth size and shape, jaw size and relationship, facial type, growth patterns, neuromuscular functioning and specific traits like overbite. Studies using twins help determine the hereditary component. While genetics play a role, environmental influences can also modify the hereditary pattern.
This document discusses the diagnosis and treatment of anterior dental crossbites. It defines crossbites as teeth that are malposed buccally, lingually, or labially in relation to the opposing teeth. Anterior crossbites require early treatment to prevent enamel abrasion, tooth mobility, and other issues. Treatment aims to tip affected maxillary teeth labially to establish a stable overbite. Crossbites can be caused by dental anomalies or skeletal issues and are classified as single, segmental, or posterior. Diagnosis involves evaluating the number of teeth involved, tooth inclinations, facial profile, and cephalometric analysis. Treatment may involve appliances like tongue blades, springs, or expanders to correct dental or functional
This document provides an overview of mixed dentition and orthodontic appliances used during this period. Mixed dentition refers to the stage when primary teeth are being replaced by permanent teeth, between ages 6-13 years. Common orthodontic problems in mixed dentition include increased overjet and open bite. Functional appliances discussed include oral screens, lip bumpers, activators, and Frankel's regulator. Other appliances mentioned are space maintainers, tongue blades for crossbite correction, and space regainers. The document outlines the principles, advantages, limitations and indications for different appliances used in intercepting and correcting malocclusions during mixed dentition.
The document discusses various classifications of malocclusion and their etiologies. White and Gardiner's classification distinguished between skeletal and dental factors, as well as pre-eruptive and post-eruptive causes. Salzmann's classification defined three stages - genetic, fetal environment, and postnatal environment - that influence malocclusion development. Moyer's classification identified four sites of etiologic variation: the craniofacial skeleton, dentition, orofacial musculature, and other soft tissues. Graber's comprehensive classification divided factors into general (e.g. heredity, environment) and local (e.g. anomalies in tooth number, shape).
Genaral factors of malocclusion of teethMaher Fouda
General factors that can cause malocclusion include heredity, congenital defects, environmental influences, nutritional deficiencies, and metabolic diseases. Hereditary factors pass traits from parents to children that can influence the neuromuscular system, dentition, skeletal structures, and soft tissues. Congenital defects present at birth include micrognathism, oligodontia, anodontia, cleft palate, and cleidocranial dysplasia. Environmental influences consist of prenatal issues like maternal trauma or diseases and postnatal issues like birth injuries or cerebral palsy. Nutritional deficiencies in pregnancy like rickets can disturb facial bone growth. Predisposing metabolic diseases and endocrine imbalances such as dwarfism
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.for more details please visit
www.indiandentalacademy.com
This document discusses various developmental disturbances that can affect the size, shape, number and structure of teeth. Regarding size, it describes microdontia where teeth are smaller than normal, and macrodontia where teeth are larger. For shape, it discusses anomalies such as gemination, fusion, concrescence and dilaceration. It also covers rare formations like talon cusps, dens in dente and dens evaginatus. The number of teeth can be affected by complete anodontia where no teeth form, or supernumerary teeth where extra teeth are present. Radiographic and clinical features of each condition are provided along with potential causes and treatments.
This document provides an overview of the classification of malocclusions. It begins with definitions of key terms like occlusion, ideal occlusion, normal occlusion, and malocclusion. It then discusses the need for classifying malocclusions to aid in diagnosis and treatment planning. The major types of malocclusions covered are intra-arch, inter-arch, and skeletal malocclusions. Several classification systems are then described in detail, including Angle's classification, Dewey's modification, Lischer's modification, Bennett's classification, and the Ackerman-Profitt system. The classifications are based on factors like the molar relationship, sagittal, vertical and transverse discrepancies, dental arch alignment, and incisor relationships.
The document discusses various oral habits and their effects on dentition and facial growth. It defines habits like thumb sucking, tongue thrusting, and mouth breathing. It describes William James' definition of habit formation in the brain and classifies habits as useful/harmful, pressure/non-pressure, and intraoral/extraoral. Specific sections provide details on the etiology, clinical effects, diagnosis and management of thumb sucking and tongue thrusting habits.
Class I malocclusion is the most common type of malocclusion, accounting for 60% of cases. It is characterized by a Class I incisor relationship with the canine and molar relationships usually being Class I as well. Crowding is the most common problem associated with Class I malocclusion. Crowding can be due to the tooth size being larger than the jaw size (hereditary) or due to loss of arch length from premature loss of primary teeth or caries. Treatment of crowding depends on its severity and can include space maintenance, expansion, serial extraction, or orthodontic treatment with extraction of premolars.
Orthodontic study models are three-dimensional plaster reproductions of a patient's teeth and surrounding tissues that are used to accurately diagnose and monitor orthodontic treatment. The document outlines the requirements, uses, and proper procedures for fabricating and trimming study models. Key steps include accurately reproducing the dental anatomy, trimming bases and backs at specific angles, and using wax bites and articulators to achieve proper occlusion. Study models provide a permanent record for treatment planning, evaluation, and legal documentation of a patient's orthodontic condition and progress.
Orthodontic Case History and ExaminationAhmed Gamil
The document discusses essential and supplemental diagnostic aids used in orthodontic diagnosis. Essential aids include case history, clinical examination, study models, and certain radiographs. Supplemental aids provide additional information and include specialized radiographs, electromyography, and biopsy. A thorough case history covers chief complaint, medical/dental history, and family history. Clinical examination assesses facial symmetry, profile, jaw relationships, and soft tissues. Essential radiographs aid in case evaluation and treatment planning.
This document provides an overview of orthodontic anchorage. It defines anchorage and discusses different classifications including: simple vs stationary anchorage based on force application; intra-maxillary vs inter-maxillary anchorage based on jaw movement; and single vs compound anchorage based on number of units. Sources of anchorage are described including teeth, alveolar bone, musculature, and extra-oral units like headgear. Mini dental implants are presented as a method for anchorage. Factors in anchorage planning and potential anchorage loss in the sagittal, vertical, and transverse planes are also summarized.
The document summarizes the functional matrix theory of bone growth proposed by Melvin Moss. The theory states that bone growth occurs as a response to functional needs mediated by soft tissues, rather than bones growing independently. Growth involves periosteal matrices altering bone size in response to soft tissue demands, and capsular matrices passively translating bones during expansion. Experiments on rats supported the theory by showing bones altered in size and shape following muscle resection. Clinical implications include functional appliances altering bone growth by changing soft tissue pressures.
This document provides information about the steps involved in orthodontic diagnosis and treatment planning. It discusses essential diagnostic aids like case history, clinical examination including extra-oral and intra-oral examination, study casts, radiographs, and facial photographs. Supplemental diagnostic aids like specialized radiographs and electromyography are also mentioned. The conclusion restates that orthodontic diagnosis involves systematically collecting data to identify the nature and cause of a malocclusion.
This document discusses post-natal growth of the maxilla and mandible. It describes how the maxilla grows through primary and secondary translation at sutures, through surface bone remodeling, and through palatal remodeling which follows the 'V' principle. The mandible grows most during the post-natal period through growth at the condylar cartilage which pushes the mandible downward and forward. Both bones exhibit growth changes with age and can be affected by various developmental anomalies. Understanding their normal and abnormal growth is important for orthodontic diagnosis and treatment planning.
Natal and neonatal teeth refer to teeth that are present at birth or erupt within 30 days of birth. The incidence is estimated to be 1 in 1000 for natal teeth and 1 in 30,000 for neonatal teeth, with the majority being mandibular incisors. These premature teeth can cause issues with breastfeeding and tongue laceration. Radiographs are needed to assess root development and mobility. Teeth that are excessively mobile or interfering with breastfeeding should be removed to prevent aspiration risk and further trauma.
Orthodontic diagnosis deals with recognition of the various characteristics of the malocclusion. It involves collection of pertinent data in a systemic manner to help in the identifying the nature and cause of the problem.
The document discusses different types of anchorage used in orthodontics. It defines anchorage as the resistance used to overcome the reaction to an applied force. There are different factors that affect a tooth's resistance to force, as well as different types of anchorage including extra-oral anchorage like headgear and intra-oral anchorage that can be intra-maxillary or inter-maxillary. Examples of each type are provided. Temporary orthodontic micro anchorage systems are also discussed as a modern method to reinforce anchorage.
Space maintainers are appliances used to maintain space or regain minor amounts of space lost after a primary tooth is lost. There are several types of space maintainers including fixed appliances like band and loop, lingual arch, and distal shoe appliances as well as removable partial dentures. Key factors in determining the appropriate space maintainer include the amount of time since tooth loss, dental age of the patient, amount of bone covering the unerupted tooth, and sequence of eruption of surrounding teeth. Space maintainers aim to guide unerupted teeth into proper positions and prevent over-eruption of opposing teeth.
This document discusses the etiology and classifications of malocclusions. It begins by introducing Graber's classification of etiology, which divides factors into general and local. General factors include hereditary influences on neuromuscular, skeletal, soft tissue and dental structures. Local factors relate to anomalies in tooth number, size, shape, frenums, eruption patterns and loss of primary teeth. The document then examines various classifications in detail, outlining prenatal, postnatal, functional and environmental/acquired etiologies. Specific hereditary, congenital, nutritional and traumatic influences are explored.
1) Malocclusions have complex multifactorial causes involving both genetics and environmental influences during development.
2) Specific causes can include disturbances during embryonic development, growth issues in the fetal or perinatal period, childhood deformities, dental issues, or problems arising in adolescence.
3) Environmental influences like sucking habits, respiratory patterns, and masticatory function may also play a role, though the evidence is mixed.
hereditary factors etiology of malocclusionParag Deshmukh
This document discusses various classifications of malocclusion causes and the role of heredity in malocclusion. It provides an overview of White and Gardiner's, Moyer's, Graber's, Houston's and Proffit's classifications of etiological factors. Genetic factors that can influence malocclusion include tooth size and shape, jaw size and relationship, facial type, growth patterns, neuromuscular functioning and specific traits like overbite. Studies using twins help determine the hereditary component. While genetics play a role, environmental influences can also modify the hereditary pattern.
This document discusses the diagnosis and treatment of anterior dental crossbites. It defines crossbites as teeth that are malposed buccally, lingually, or labially in relation to the opposing teeth. Anterior crossbites require early treatment to prevent enamel abrasion, tooth mobility, and other issues. Treatment aims to tip affected maxillary teeth labially to establish a stable overbite. Crossbites can be caused by dental anomalies or skeletal issues and are classified as single, segmental, or posterior. Diagnosis involves evaluating the number of teeth involved, tooth inclinations, facial profile, and cephalometric analysis. Treatment may involve appliances like tongue blades, springs, or expanders to correct dental or functional
This document provides an overview of mixed dentition and orthodontic appliances used during this period. Mixed dentition refers to the stage when primary teeth are being replaced by permanent teeth, between ages 6-13 years. Common orthodontic problems in mixed dentition include increased overjet and open bite. Functional appliances discussed include oral screens, lip bumpers, activators, and Frankel's regulator. Other appliances mentioned are space maintainers, tongue blades for crossbite correction, and space regainers. The document outlines the principles, advantages, limitations and indications for different appliances used in intercepting and correcting malocclusions during mixed dentition.
The document discusses various classifications of malocclusion and their etiologies. White and Gardiner's classification distinguished between skeletal and dental factors, as well as pre-eruptive and post-eruptive causes. Salzmann's classification defined three stages - genetic, fetal environment, and postnatal environment - that influence malocclusion development. Moyer's classification identified four sites of etiologic variation: the craniofacial skeleton, dentition, orofacial musculature, and other soft tissues. Graber's comprehensive classification divided factors into general (e.g. heredity, environment) and local (e.g. anomalies in tooth number, shape).
Genaral factors of malocclusion of teethMaher Fouda
General factors that can cause malocclusion include heredity, congenital defects, environmental influences, nutritional deficiencies, and metabolic diseases. Hereditary factors pass traits from parents to children that can influence the neuromuscular system, dentition, skeletal structures, and soft tissues. Congenital defects present at birth include micrognathism, oligodontia, anodontia, cleft palate, and cleidocranial dysplasia. Environmental influences consist of prenatal issues like maternal trauma or diseases and postnatal issues like birth injuries or cerebral palsy. Nutritional deficiencies in pregnancy like rickets can disturb facial bone growth. Predisposing metabolic diseases and endocrine imbalances such as dwarfism
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.for more details please visit
www.indiandentalacademy.com
This document discusses various developmental disturbances that can affect the size, shape, number and structure of teeth. Regarding size, it describes microdontia where teeth are smaller than normal, and macrodontia where teeth are larger. For shape, it discusses anomalies such as gemination, fusion, concrescence and dilaceration. It also covers rare formations like talon cusps, dens in dente and dens evaginatus. The number of teeth can be affected by complete anodontia where no teeth form, or supernumerary teeth where extra teeth are present. Radiographic and clinical features of each condition are provided along with potential causes and treatments.
This document provides an overview of the classification of malocclusions. It begins with definitions of key terms like occlusion, ideal occlusion, normal occlusion, and malocclusion. It then discusses the need for classifying malocclusions to aid in diagnosis and treatment planning. The major types of malocclusions covered are intra-arch, inter-arch, and skeletal malocclusions. Several classification systems are then described in detail, including Angle's classification, Dewey's modification, Lischer's modification, Bennett's classification, and the Ackerman-Profitt system. The classifications are based on factors like the molar relationship, sagittal, vertical and transverse discrepancies, dental arch alignment, and incisor relationships.
The document discusses various oral habits and their effects on dentition and facial growth. It defines habits like thumb sucking, tongue thrusting, and mouth breathing. It describes William James' definition of habit formation in the brain and classifies habits as useful/harmful, pressure/non-pressure, and intraoral/extraoral. Specific sections provide details on the etiology, clinical effects, diagnosis and management of thumb sucking and tongue thrusting habits.
Class I malocclusion is the most common type of malocclusion, accounting for 60% of cases. It is characterized by a Class I incisor relationship with the canine and molar relationships usually being Class I as well. Crowding is the most common problem associated with Class I malocclusion. Crowding can be due to the tooth size being larger than the jaw size (hereditary) or due to loss of arch length from premature loss of primary teeth or caries. Treatment of crowding depends on its severity and can include space maintenance, expansion, serial extraction, or orthodontic treatment with extraction of premolars.
Orthodontic study models are three-dimensional plaster reproductions of a patient's teeth and surrounding tissues that are used to accurately diagnose and monitor orthodontic treatment. The document outlines the requirements, uses, and proper procedures for fabricating and trimming study models. Key steps include accurately reproducing the dental anatomy, trimming bases and backs at specific angles, and using wax bites and articulators to achieve proper occlusion. Study models provide a permanent record for treatment planning, evaluation, and legal documentation of a patient's orthodontic condition and progress.
Orthodontic Case History and ExaminationAhmed Gamil
The document discusses essential and supplemental diagnostic aids used in orthodontic diagnosis. Essential aids include case history, clinical examination, study models, and certain radiographs. Supplemental aids provide additional information and include specialized radiographs, electromyography, and biopsy. A thorough case history covers chief complaint, medical/dental history, and family history. Clinical examination assesses facial symmetry, profile, jaw relationships, and soft tissues. Essential radiographs aid in case evaluation and treatment planning.
This document provides an overview of orthodontic anchorage. It defines anchorage and discusses different classifications including: simple vs stationary anchorage based on force application; intra-maxillary vs inter-maxillary anchorage based on jaw movement; and single vs compound anchorage based on number of units. Sources of anchorage are described including teeth, alveolar bone, musculature, and extra-oral units like headgear. Mini dental implants are presented as a method for anchorage. Factors in anchorage planning and potential anchorage loss in the sagittal, vertical, and transverse planes are also summarized.
The document summarizes the functional matrix theory of bone growth proposed by Melvin Moss. The theory states that bone growth occurs as a response to functional needs mediated by soft tissues, rather than bones growing independently. Growth involves periosteal matrices altering bone size in response to soft tissue demands, and capsular matrices passively translating bones during expansion. Experiments on rats supported the theory by showing bones altered in size and shape following muscle resection. Clinical implications include functional appliances altering bone growth by changing soft tissue pressures.
This document provides information about the steps involved in orthodontic diagnosis and treatment planning. It discusses essential diagnostic aids like case history, clinical examination including extra-oral and intra-oral examination, study casts, radiographs, and facial photographs. Supplemental diagnostic aids like specialized radiographs and electromyography are also mentioned. The conclusion restates that orthodontic diagnosis involves systematically collecting data to identify the nature and cause of a malocclusion.
This document discusses post-natal growth of the maxilla and mandible. It describes how the maxilla grows through primary and secondary translation at sutures, through surface bone remodeling, and through palatal remodeling which follows the 'V' principle. The mandible grows most during the post-natal period through growth at the condylar cartilage which pushes the mandible downward and forward. Both bones exhibit growth changes with age and can be affected by various developmental anomalies. Understanding their normal and abnormal growth is important for orthodontic diagnosis and treatment planning.
Natal and neonatal teeth refer to teeth that are present at birth or erupt within 30 days of birth. The incidence is estimated to be 1 in 1000 for natal teeth and 1 in 30,000 for neonatal teeth, with the majority being mandibular incisors. These premature teeth can cause issues with breastfeeding and tongue laceration. Radiographs are needed to assess root development and mobility. Teeth that are excessively mobile or interfering with breastfeeding should be removed to prevent aspiration risk and further trauma.
Orthodontic diagnosis deals with recognition of the various characteristics of the malocclusion. It involves collection of pertinent data in a systemic manner to help in the identifying the nature and cause of the problem.
The document discusses different types of anchorage used in orthodontics. It defines anchorage as the resistance used to overcome the reaction to an applied force. There are different factors that affect a tooth's resistance to force, as well as different types of anchorage including extra-oral anchorage like headgear and intra-oral anchorage that can be intra-maxillary or inter-maxillary. Examples of each type are provided. Temporary orthodontic micro anchorage systems are also discussed as a modern method to reinforce anchorage.
Space maintainers are appliances used to maintain space or regain minor amounts of space lost after a primary tooth is lost. There are several types of space maintainers including fixed appliances like band and loop, lingual arch, and distal shoe appliances as well as removable partial dentures. Key factors in determining the appropriate space maintainer include the amount of time since tooth loss, dental age of the patient, amount of bone covering the unerupted tooth, and sequence of eruption of surrounding teeth. Space maintainers aim to guide unerupted teeth into proper positions and prevent over-eruption of opposing teeth.
This document discusses the etiology and classifications of malocclusions. It begins by introducing Graber's classification of etiology, which divides factors into general and local. General factors include hereditary influences on neuromuscular, skeletal, soft tissue and dental structures. Local factors relate to anomalies in tooth number, size, shape, frenums, eruption patterns and loss of primary teeth. The document then examines various classifications in detail, outlining prenatal, postnatal, functional and environmental/acquired etiologies. Specific hereditary, congenital, nutritional and traumatic influences are explored.
1) Malocclusions have complex multifactorial causes involving both genetics and environmental influences during development.
2) Specific causes can include disturbances during embryonic development, growth issues in the fetal or perinatal period, childhood deformities, dental issues, or problems arising in adolescence.
3) Environmental influences like sucking habits, respiratory patterns, and masticatory function may also play a role, though the evidence is mixed.
This document discusses the etiology and classification of malocclusion. It identifies several local and general factors that can cause malocclusion, including heredity, congenital defects, environmental factors like thumb sucking and tongue thrusting, metabolic diseases, accidents or trauma, anomalies in tooth number or size, and abnormal frenum or dental restorations. It provides examples for each factor and their effects on dental alignment. Congenital defects discussed in detail include clefts of the lip and palate, congenital syphilis, and macro/microglossia.
etiology of malocclusion for general practitioners.docxDr.Mohammed Alruby
Etiology of Malocclusion
For general practitioners
Prepared by
Dr. M Alruby
Etiology in orthodontics is the study of actual causes of dento – facial abnormalities.
Malocclusion is the condition where there is a deviation from the usual or accepted relationship, dental malocclusion exists when the individual teeth within one or both jaws are abnormally related to each other, this condition may be limited to a couple of teeth or involving the majority of teeth present.
Development of normal dentition and occlusion depends on a number of interrelated factors that include the dento alveolar, skeletal and the neuromuscular factors. Thus localization of the possible etiology may be a very difficult task.
A- Extrinsic factors:
1- Evolution:
With evolution, the jaws become smaller, reduction in the number and size of teeth and diminution of jaw projection together with increased in vertical height of the face and there is retrognathic tendency in man as he ascends the evolutionary scale.
2- Heredity:
Transmission of dento facial characteristic through generation by genes. The child is a product of parents who have dissimilar genetic material. Thus the child may inherit conflicting traits from both the parents resulting in abnormalities of the dentofacial region. Another reason attributed for genetically determined malocclusion is the racial, ethnic and regional intermixer, which might have led to uncoordinated inheritance of teeth and jaws.
There are three types of transmission of malocclusion from the stand point of genetics:
1- Repetitive: the recurrence of single dentofacial deviation within the immediate family.
2- Discontinuous: a tendency for a malocclusion trait to reappear within the family over several generations.
3- Variable: the occurrence of different but related types of malocclusion within several generation of the same family.
Dental defect of genetic origin include the following:
= Crowding and spacing of teeth.
= Size and characteristic of soft tissue including muscles and frenum.
= Macrognathia and micrognathia.
= Macrodontia and microdontia.
= Oligodontia.
= Tooth shape variations.
= Median diastemas.
= upper face height, nose height, and bigonial width.
= Bimaxillary protrusion.
4- Congenital:
Those are deformities of hereditary or non-hereditary origin but exciting at birth.
The congenital abnormalities that cause malocclusion:
= Cleft lip and palate:
lack of fusion between the two palatal processes to each other. From one third to one half of all cleft palate children have familial history of this deformity.
As with the non-cleft child, palatal, pharyngeal and perioral musculature is well developed at birth to meet the demand of suckling, deglutition and mastication. While the complete unilateral or complete bilateral cleft break the continuity of the upper lip and disturbs the functional pattern and significantly reduce the restraining effect of the buccinators mechanism that pro
The document discusses delayed tooth eruption, including its causes and characteristics. It describes the normal phases of tooth eruption and defines delayed eruption. Potential causes of delayed eruption include local conditions like scarring from trauma or tumors, systemic conditions such as nutritional deficiencies, endocrine disorders, and genetic syndromes. Specific local conditions discussed in detail are mucosal barriers, odontogenic tumors, ankylosis of deciduous teeth, radiation damage, and oral clefts. Systemic conditions explored include malnutrition, vitamin D-resistant rickets, hypothyroidism, hypopituitarism, hypoparathyroidism, HIV infection, cerebral palsy, celiac disease, and ichthyosis
This document discusses the etiology (causes) of malocclusion according to Graber's classification. Graber classified etiological factors into general factors and local factors. Some key general factors discussed include heredity, congenital defects, environment like prenatal/postnatal factors, and predisposing metabolic/endocrine diseases. Local factors refer to more localized dental anomalies affecting one or a few teeth. The document provides examples and descriptions of various general and local factors that can cause malocclusion.
Primary etiologic sites:
1- Neuromuscular system:
The muscle group that serve most frequently as primary etiologic sites are:
== muscles of mastication
== muscles of facial expression
== tongue
The neuromuscular system plays its primary role in the etiology of dentofacial deformity by the effect of abnormal contraction of bony skeleton and the dentition. Both bones and teeth are affected by the many functional activities of orofacial region
2- Bone:
Since the bone pf maxilla and mandible serve as bases of dental arches, changes in dental arches growth may alter the occlusal and functional relationship.
3- Teeth;
The teeth may be primary sites in the etiology of dentofacial deformity in many ways
Gross variation in size and shape are encountered frequently and always are of concern
Decrease or increase in the regular number of teeth will give rise malocclusion
Etiologic factors:
A- Extrinsic factors:
1- Evolution:
With evolution, the jaws become smaller, reduction in number and size of teeth and diminution of jaw projections together with increased in vertical height of the face and there is a retrognathic tendency in mans as he ascends the evolutionary scale
2- Heredity:
Transmission of dentofacial characteristics through generations by genes. Most authors between 1900-- 1920 did not completely determine the role of inheritance in determination of the form, size and proportion of dentofacial skeleton, but they stress their work upon the effect of the environmental factors, and at this time they were hardly belief that the effect of local lack of function is more important.
Bennet statement: the size, form and density of bones such as maxilla and mandible varies according to the extent to which these structure are used during period of growth – (function stimulate growth)
Walk Joff statement: the form and degree of development of maxilla and mandible depends upon the magnitude of functional stimuli of muscles acting upon these structures.
Baker: his study was performed on animals by unilateral amputation of muscles of mastication, he found lack of growth on the affected side.
Brash: studied the facial form and the dental development in twins on genetic bases, he also emphasized the genetic facial pattern of some royal families in Europe where they had been inter-marriage, his studies gave the best evidence to support the role of inheritance
Axel Lundstorm:1925 showed that, the form and size of dental bases and the teeth are genetically determined, when the size of the teeth and their basal arches are not correlated, problems of crowding or spacing will be arising.
Broadbent and Hofrath 1931: developed standardized cephalometric x-ray technique which permit serial longitudinal studies of facial growth, by this studies the concept of inheritance growth pattern arises
There are three types of transmission of malocclusion from the standpoint of genetics:
a- Repetitive: the recurrence of single dentofacial deviation within the immediate famil
This document discusses various classifications of malocclusion etiologies proposed by experts including White and Gardiner, Salzmann, Moyer, and Graber. The classifications distinguish between skeletal and dental factors, pre-eruptive and post-eruptive causes, and categorize etiologies as prenatal, postnatal, functional, environmental/acquired, or based on anatomical sites of variation. Common malocclusion causes discussed include genetics, developmental abnormalities, trauma, habits like thumb sucking, premature tooth loss, and nutritional deficiencies.
This document discusses various aspects of occlusion including terminology, factors that influence occlusion, and concepts of occlusion. It defines terms like normal occlusion, ideal occlusion, physiologic occlusion, and traumatic occlusion. It describes how factors like development of dentition, dental arch form, occlusal plane curvatures, tooth inclination/angulation, occlusal morphology, and facial/lingual tooth relations influence occlusion. It also covers concepts of centric occlusion, balanced occlusion, static vs dynamic occlusion, tooth guidance, and occlusal contacts in different excursive movements.
Etiology of Malocclusion_ Genral Factors Dr.Nabil Al-ZubairNabil Al-Zubair
The document discusses the aetiology (causes) of malocclusion. It states that malocclusion is usually caused by distortions in normal development rather than pathology. It can result from complex interactions between multiple factors that influence growth and development. These factors include abnormalities in skeletal relationships, soft tissue factors like muscles and lips, and disproportion between tooth size and arch length. The document provides examples of each type of factor and how they can contribute to malocclusion.
This document discusses the etiology and classification of malocclusion. It describes several common factors that can cause malocclusions, including hereditary influences, congenital defects, environmental factors, and local dental anomalies. It provides detailed explanations of various classification systems for malocclusion etiologies proposed by researchers like McCoy, Moyer, Salzmann, White and Gardiner, Proffit, and Graber. Common local factors discussed include anomalies in tooth number, size, shape, as well as the effects of prolonged retention of primary teeth and abnormal labial frenum.
This document discusses various factors related to tooth eruption patterns in humans, including:
- Hormonal and genetic influences on the timing and sequence of eruption.
- Conditions like Down syndrome and cleidocranial dysplasia that cause delayed or abnormal eruption.
- Local factors like premature loss of primary teeth or ankylosis that can influence eruption.
- Rare occurrences of natal or neonatal teeth emerging at birth or within the first month of life.
This document provides an overview of developmental disturbances of the jaws and teeth. It begins with introductions and terminology. It then discusses various developmental disturbances that can affect the jaws, such as agnathia, micrognathia, macrognathia, and clefts. Tooth disturbances covered include anomalies in size, number, morphology, structure, and position. Specific conditions discussed include microdontia, hypodontia, taurodontism, amelogenesis imperfecta, and dens invaginatus. Finally, the document examines some developmental cysts of the jaws, such as the nasopalatine duct cyst, median palatal cyst, and Stafne cyst. The conclusion thanks the reader.
Malocclusion can be caused by local developmental factors that disrupt the normal growth and alignment of teeth. These include abnormalities in tooth number, size, shape, and eruption due to issues like missing teeth, supernumeraries, trauma, premature loss of primary teeth, prolonged retention of primary teeth, and delayed eruption of permanent teeth. Premature loss of primary teeth is a leading cause of malocclusion since it allows other teeth to drift out of position. Improper dental restorations can also disrupt contacts and cause teeth to rotate out of alignment. Most malocclusions are due to moderate distortions in normal development rather than pathological processes.
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This document discusses preventive orthodontics and measures taken to prevent malocclusion in children. It focuses on caries control, periodontal health, and preventing malocclusion. Key aspects include periodic oral examinations of children to detect early problems, preservation of arch length, replacement of lost primary teeth with space maintainers, and intercepting potential irregularities to facilitate future treatment. Conditions that can cause orthodontic problems include crowding, mismatch of tooth and jaw size, breathing issues, and thumb sucking. The general factors influencing malocclusion with premature tooth loss include abnormal oral muscles, oral habits, existing malocclusion, and erupting teeth adjacent to space left by loss.
The document discusses the development of dentition from prenatal stages through adulthood. It covers the evolutionary stages of teeth, prenatal development including initiation, bud, cap and bell stages. Tooth eruption mechanisms and theories are explained. The phases of occlusion development are described for the pre-dental, deciduous dentition, mixed dentition and permanent dentition periods. Transient malocclusions and Andrews six keys of occlusion are briefly introduced.
This document provides definitions and an overview of oral pathology. It defines key terms like pathology, oral pathology, disease, signs, symptoms, etiology, and pathogenesis. It then discusses variations that can affect teeth, including variations in number (increase or decrease), size (macrodontia or microdontia), shape (gemination, fusion, etc.), and structure (enamel hypoplasia, hypocalcification, etc.). For each variation, it provides examples and classifications. It discusses specific conditions like amelogenesis imperfecta and dental fluorosis in more depth. Overall, the document concisely covers a wide range of topics relating to anomalies and defects that can affect dental development and structure.
This document discusses cleft lip and cleft palate, which are birth defects where the lip and roof of the mouth do not fully form. Cleft lip involves a separation of the upper lip, while cleft palate involves an opening in the roof of the mouth. The causes may include genetic and environmental factors. Treatment requires a team approach including surgery and other therapies. Dental problems are common in individuals with cleft lip and palate.
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4. OCCLUSION :
The term “occlusion” has both static &
dynamic aspects.
• Static- the form , alignment and articulation of teeth
within & between the arches, the relationship of teeth
to their supporting structure.
• Dynamic – the function of the stomatognathic system
as a whole comprising teeth, supporting structure ,
TMJ, neuromuscular and nutritive sytems.
• Angle defined – “occlusion as the normal relation of the
occlusal inclined planes of the teeth when the jaws are
closed.”
6. MALOCCLUSION
• Malocclusion is a condition in which there
is deflection from the normal relation of
the teeth to other teeth in the same arch
and/or to teeth n the opposing arch
7.
8.
9.
10.
11.
12.
13.
14. GRABER’S CLASSIFICATION
• Graber divided the etiological factors as local and
general factors and presented a very comprehensive
classification .
• Local factors General factors
These are responsible for
malocclusion produce a
localized effect confined
to one or more adjacent or
opposing teeth.
On the other hand these are
those that affect the body as
a whole & have a profound
effect on the greater part of
the dento facial structures.
17. • According to Lundstrom there exists a no of human traits
that are influenced by the genes that include
• Abnormalities such as Microdontia,
Macrodontia are attributed to heredity
1. Tooth size
• The arch length and arch width are
believed to be inherited.
2. Arch Dimensions
• Probably result of uncoordinated
inheritence of arch length and tooth
material
3. Crowding
• Anomaly such as peg shaped laterals
shows high genetic predisposition
4. Abnormalities of
tooth shape
• Anodontia , oligodontia5. Abnormalities of
tooth number
18. • The horizontal overlap of the upper
and lower dentition – is believed to
be genetically influenced.
6. Overjet
• Discrepencies in the
transverse , sagittal and
vertical planes between the
upper & lower jaws can be
inherited.
7. Inter Arch
Variation
• Malocclusions such as Midline Diastema –
that may be due to abnormalities of the
frenum are to a large extent are
determined genetically
8. Frenum
19. • According to Harris & Johnson – a no of craniofacial parameters showed
significant genetic influence .
• These include the following distances:
o Sella- Gnathion
o Sella- Point A
o Sella – Gonion
o Nasion- ANS
o Articulare- Pogonion
o Bizygomatic Width
o Anterior Facial Height
• As so many traits show a strong genetic pattern a no of malocclusions
can be partly or solely attributed to genetic factors. These genetic
traits can be further influenced by existing pre-natal or post-natal
environment factors.
20.
21. 1. Abnormal state of mother during pregnancy
2. Malnutrition
3. Endocrinopathies
4. Infectious diseases
5. Metabolic & nutritional disturbances
6. Accidents during pregnancy and childbirth
7. Intra uterine pressure
8. Accidental traumatisation of the foetus by
external forces.
22. • Abnormalities of jaw development due to intra-
uterine position.
• Clefts of the face and palate
• Macro and microglossia
• Cleidocranial dysostosis
23.
24. CLEFT LIP & PALATE
• Clefts are evelopmental defects that occur as
a result of non fusion between the various
embryonic proocesses.
• Cleft patients may exhibit –
missing teeth
mobile teeth
rotations, lingual
crossbites etc
25.
26. • Hutchinson’s incisors
• Mulberry molars
• Enamel deficiencies
• Extensive dental decay
• The maxilla may be smaller in size relative to
the mandible
• Anterior cross bite
27.
28. • Maternal viremia associated with Rubella infection during early
pregnancy may result in infection of the placenta & fetus.
• Fetal cells become infected , growth rate reduced , deranged &
hypoplastic organ development – resulting in structural anomalies.
• Some of the features that can be seen are –
a) Dental hypoplasia
b) Retarded eruption of teeth
c) Extensive caries
29.
30. • Absence of clavicle (collar bone) which may be unilateral or
bilateral ; partial or complete.
• Patient may exhibit --
a) Maxillary retrusion and possible mandibular protrusion
b) Over retained deciduous teeth and retarded eruption of
permanent teeth.
c) Presence of supernumerary teeth
d) Presence of short and thin roots
31. • The patient lacks muscular co ordination
• It usually occurs due to birth injuries
• The uncontrolled and aberrant muscle activity upsets the muscle
balance resulting in malocclusion .
• Exposure to radiation / infection , hypoxia – probably are the
causes of underdevelopment of some areas of the brain.
32.
33. • Abnormal fetal posture – interfere with symmetric
development of the face (usually disappers as the age
advances)
• Maternal fibroids
• Amniotic lesions
• Maternal diet & metabolism
• Maternal infetions such as German measles and use of
certain drugs during pregnancy such as –Thalidomide can
cause gross congenital deformities including clefts.
34. a) Forceps delivery – injury to the Temporomandibular
Joint area – which may undergo ankylosis- such
patients show retarded mandibular growth & hence
hypoplastic mandible.
b) Cerebral palsy – characterised by muscle
incoordination . This may occur due to birth injuries ,
exposure to radiation or infection , hypoxia etc .
c) Traumatic injuries that cause condylar fracture –
growth retardation resulting in marked facial
assymmetry .
d) Milwaukee braces – that are used for the treatment
of scoliosis – derive support from the mandible.
Prolonged use – can cause marked mandibular
retardation
35.
36. • includes – chicken pox, measles, scarlet fever etc
• Ameloblasts may be affected under increased body
temperature.
characterized by
retardation in the rate of Ca deposition in bones and teeth
Marked delay in tooth bud formation and eruption of teeth.
Delayed carpel & epiphyseal calcification.
The deciduous teeth are often over-retained & the permanent
teeth are slow to erupt .
Abnormal root resorbtion
Irregularities in tooth arrangement & crowding of teeth may
occur.
37. • Increase in the rate of maturation and an increase in
the metabolic rate.
• Premature eruption of deciduous teeth
• Disturbed root resorption of deciduous teeth
• Early eruption of permanent teeth
• Patient may have OSTEOPOROSIS which contra indicates
orthodontic treatment.
38. • Changes in Ca metabolism
• Delay in tooth eruption
• Altered tooth morphology
• Delayed eruption of deciduous and permanent teeth &
hypoplastic teeth
• Increase in blood Ca
• Demineralisation of bone & disruption of trabecular pattern .
• Interruption of tooth development – in growing children .
• The teeth may become mobile due to loss of cortical bone &
resorbtion of alveolar process.
39. • Acute febrile illness – slow down the pace of
growth & development.
• These conditions may cause a disturbance in
tooth eruption and shedding – inrease the risk
of malocclusion
40. • Nutritional deficiencies during growth may result in
abnormal development –causing malocclusion .
• These diseases are more common in developing countries
than in the developed world.
• Examples are – Rickets (vit D)
• - scurvy (Vit C/Ascorbic acid)
• - beri beri (vit B1/ thiamin)
• These can produce severe malocclusion and may upset the
dental development timetable.
41.
42.
43. • EFFECTS OF THUMB SUCKING :
• The severity of the malocclusion caused by thumb sucking depends
on the – duration , frequency & the intensity of the habit.
1. Labial tipping of the maxillary anterior teeth resulting in
proclination of the maxillary anteriors
2. The overjet increases.
3. Anterior open bite – as a a result of restriction of incisor eruption
and supraeruption of buccal teeth.
4. The cheek muscles contract during thumb sucking resulting in a
narrow maxillay arch , which pre disposes to posterior cross bites.
5. As a result of open bite, the child may also develop tongue thrust.
6. The upper lip is usually hypotonic while the lower part of the face
exhibits hyperactive mentalis activity.
44.
45. • Clinical features :
1. Proclincation of anterior teeth
2. Anterior open bite
3. Bimaxillary protrusion
4. Posterior open bite in case of lateral tongue
thrust
5. Posterior cross bite
48. • Lip biting and lip sucking appear after forced discontinuation of
thumb or finger sucking
• Lip biting most often involves the lower lip that is turned
inwards & pressure is exerted on the lingual surfaces of the
maxillary anteriors. The patient may exhibit –
Proclined upper and retroclinded lower anterisor
Hypertrophic and redundant lower lip
Cracking of lips
NAIL BITING doesn’t produce gross malocclusion
People in certain countries – middle edge exhibits what is called
the nut notch
49.
50. • The mode of respiration influences the posture of
the jaw , the tongue , and to a lesser extent .. The
head.
• Altered jaw & tongue posture because of mouth
breathing can alter the oro-facial equilibrium thereby
leading to malocclusion.
• Most normal people indulge to mouth breathing when
they’re under physical exertion.
51. • Long and narrow face
• Short & flaccid upper lip
• Contracted upper arch with possibility of cross bite.
• Increased overjet as a result of flaring of the incisors.
52. • Mature swallow pattern develops at around 4-5 yrs. It is
characterised by –
I.Relaxation of the lips
II.Placement of the tongue behind the upper central
incisors
III.Elevation of the mandible until posterior teeth are in
contact.
• Retained infantile swallow pattern is defined as the undue
peristence of the infantile swallow even after normal time
of its departure.
• These patients occlude only on one molar –in each
segment.
53. • Speech is largely a learned activity,or
an acquired activity.
• A large no of muscles are involved in the
production of speech.
• It doesn’t make gross demands on the
peri oral musculature and hence speech
defects are rarely a cause for
malocclusion.
54.
55.
56. BRUXISM
• Psychological & emotional stresses have
been attributed as one of the causes.
• Occlusal wear facets can be observed
on the teeth .
• Fractures of teeth and restorations
• Tenderness & hypertrophy of the
masticatory muscles.
57. • Children who support their head by resting the chin
on their hand and those who hang their head so that
the chin rests against their chest – are observed to
have mandibular deficiency.
58. • Children are highly prone to injuries of the
dentofacial region during the early years of
life
When they learn to crawl, walk or during play
Most of these injuries go unnoticed and may be
responsible for non vital teeth that do not
resorb and deflection of erupting permanent
teeth into abnormal position .
60. • In order to achieve good occlusion , the normal no of teeth
should be persent .
• Presence of extra teeth or absence of one or more teeth
predisposes to malocclusion.
• SUPERNUMERARY TEETH :
• Based on morphology supernumerary teeth are-
-peg shaped
-barrel shaped or tuberculate shaped
-Supplemental
-odontomes
• Over 75% of these teeth remain impacted in the bone & are only
diagnosed radiographically.
61. • Problems associated with supernumerary teeth :
1. Failure of eruption
2. Displacement or rotation of permanent teeth
3. Crowding
4. Pathology such as Dentigerous cyst formation & other complications
such as Migration into the Nasal cavity , maxillary sinus or hard palate.
MISSING TEETH :
• The following are some of the commonly missing teeth in decreasing
order of frequency .
-third molars
-maxillary Lateral Incisors
-mandibular second premolars
-mandiular incisors
Maxillary second premolars
• Absence of teeth may be unilateral or bilateral .
• Absence of one or more teeth predispose to spacing in the Dental arch.
62. • Absence of permanent teeth often results in
over retained deciduous tooth.
63. • MACRODONTIA
- Affects most often Upper central insicors & second premolars.
.and lower thirl molars.c
- Macrodontia may result in crowding while , smaller sized teeth
predispose to spacing.
- Fusion between two adjacent teeth or between a suprenumerary
tooth and a normal tooth may predispose to malocclusion .
- Most of these conditions show a positive family history.
MICRODONTIA
Smaller teeth
Hypopituitarism or exposure to radiation or chemotherapy
during dental development.
Frequently seen in association with Down’s syndrome & various
types of Ectodermal Dysplasia.
64. • PEG SHAPED MAXILLARY LATERAL INCISOR
• Often accompanied by spacing & migration of teeth.
65. • ABNORMALLY LARGE CINGULUM :
• The presence of unexaggerated cingulum prevents
establishment of normal overbite & overjet.
• The involved tooth is usually in labioversion due to the
forces of occlusion
• DEFECTS LIKE AMELOGENESIS IMPERFECTA ,
HYPOPLASIA OF TEETH , FUSION AND
GEMINATION .
• DILACERATION
66. • Prior to the eruption of teeth, the maxillary labial frenum is
attached to the alveolar ridge with some fibres crossing over
lingually to the region of the incisive papilla .
• As the teeth start erupting , alveolar bone is deposited and the
frenal attachment migrates into a more apical position
• Rarely a heavy fibrous frenum is found attached to the
interdental papilla region. This type of frenal attachment can
prevent the two maxillary central incisors from approaching
each other.
• It is diagnosed by a positive blanch test
• midline diastema may also occur due to a no of causes such as –
-presence of unerupted mesiodens
- anomalies of tooth size and number.
67.
68. • Loss of tooth before its permanent successor
is sufficiently advanced in development and
eruption –to occupy its place.
• Early loss of deciduous teeth can cause
migration of adjacent tooth into the space and
can therefore prevent the eruption of the
permanent successor.
69.
70.
71.
72.
73.
74.
75. Premature loss of second primary molar resulting in
impacted second premolar
76. • Early loss of anteriors most often doesn’t
produce any malocclusion
• The earlier the deciduous teeth are
extracted, before the successional teeth are
ready to erupt , the greater is the possibility
of malocclusion.
• In a person having arch length deficiency , or
crowding – the early loss of deciduous teeth
may worsen the existing malocclusion.
78. Adequate space has been maintained in the arch for the second
premolar by the application of space maintainer after extraction of
the primary second molar
79.
80. • Prolonged retention of deciduous anteriors usually results in
lingual or palatal eruption of the permanent successors.
• Prolonged retention of buccal teeth results in eruption of the
permanent teeth either bucally or lingually, or may remain
impacted.
• Some of the reasons for prolonged retention of decidous teeth –
o Absence of underlying permanent teeth.
o Endocranial disturbance such as hypothyroidism.
o Ankylosed deciduous teeth that fail to resorb.
81.
82. • Congenital absence of the permanent teeth
• Presence of supernumerary tooth or odontome – that block the
path of erupting permanent tooth.
• Presence of heavy mucosal barrier ------- a surgical incision in
most cases accelerates the eruption.
• Sometimes , premature loss of deciduous teeth can result in
delayed eruption of the permanent teeth because of formation
of bone over the erupting permanent tooth.
• Endocrinal disorders such as hypothyroidism.
• Presence of deciduous root fragments .
83.
84. • It could be due to
• Arch length deficiency
• Presence of supernumerary teeth
• Impacted tooth
• Retained root fragments
• Formation of bony barrier.
• The maxillary canines develop almost near the floor
of the orbit and travel down to their final position in
the oral cavity. Thus they are most often found
erupting in an abnormal position.
85. • Root surface is directly fused with the bone
• Absence of intervening periodontal membrane.
• These are called submerged tooth , because they fail
to erupt to the normal level
• At times, these teeth are totally submerged within
the jaw and therefore cause migration of adjacent
teeth into the space.
86.
87. • Caries can lead to pramature loss of
deciduous or permanent teeth
• Proximal caries that hasn’t been
restored can cause migration of the
adjacent teeth into the space leading to
reduction in arch length.
88. • Over contoured occlusal restorations cause
premature contacts leading to functional shift
of the mandible during jaw closure.
89. • Undercontoured occlusal restorations
can permit the opposing dentition to
supra erupt.
• Proximal restorations which are under
contoured invariably result in loss of
arch length due to drifting of the
adjacent teeth to occupy the space.
90.
91. • Class I malocclusion can be a discrepency either
within the arches and or in the transverse or vertical
relationship between the arches.
• The patient may exhibit dental irregularities such as
crowding, spacing, rotations, missing tooth etc.
• Local factors causing class I malocclusion may include
–
• - displaced or impacted teeth
• - anomalies in size , number & form of the
teeth.
92.
93.
94. • A deep incisor overbite can occur in the anterior region.
• Characteristic feature of this malocclusion is – the presence of
abnormal muscle activity.
• The upper lip is usually hypotonic , short and fails to form a lip
seal.
• The lower lip cushions the palatal aspect of upper teeth, a feature
typical of a class II, div 1 – referred to as “lip trap”
• The tongue occupies a lower posture thereby failing to couneract
the buccinator activity – resulting in narrowing of the upper arch
at premolar & canine regions – thereby producing a V shaped upper
arch.
• Another muscle aberration is a hyperactive mentalis activity
95.
96. • The patient exhibits deep anterior
overbite
• The lingually inclined upper centrals give
the arch a squarish appearance, unlike
the narrow v shaped arch seen in div 1.
• The patient exhibits normal perioral
muscle activity.
97. • Can occur due to the following causes :
• excessively large mandible
• Forwardly placed mandible
• Smaller than normal maxilla
• Retropositioned maxilla
• Combination of the above