Centric relation is a controversial concept in dentistry that refers to the maxillomandibular relationship where the condyles are in their most anterior and superior position against the articular eminences, allowing purely rotary movement of the mandible. There have been many changes to the definition of centric relation over time as understanding has evolved. It is important for proper functioning and to develop centric occlusion in artificial dentures. However, accurately recording centric relation can be difficult due to various biological, psychological and mechanical factors that must be addressed. Common methods include using interocclusal records with or without central bearing devices as well as functional recording techniques.
Description of Biomechanics of occlusion, Effect of anatomical determinants, Ideal occlusion, Evolution of occlusion, Concepts of Occlusion in FPD such as Group function occlusion, canine guided occlusion, Occlusal contacts, Occlusal Interferences, Patient"s adaptability, Pathogenic occlusion and Philosophies of full mouth rehabilitation. Added references for further readings.
Description of Biomechanics of occlusion, Effect of anatomical determinants, Ideal occlusion, Evolution of occlusion, Concepts of Occlusion in FPD such as Group function occlusion, canine guided occlusion, Occlusal contacts, Occlusal Interferences, Patient"s adaptability, Pathogenic occlusion and Philosophies of full mouth rehabilitation. Added references for further readings.
Neutral Zone
In dentistry, the neutral zone refers to that space in the oral cavity where the forces exerted by the musculature.of.the tongue are equal and balanced with the.forces exerted by the buccinators.muscle of the cheek.laterally and the orbicularis.oris muscle anteriorly
I will discuss various reference points for face bow.....
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The human mandible can be related to the maxilla in several positions in the horizontal plane. Among these centric relation is a significant position, because of its usefulness in relating the dentulous and edentulous mandible to maxilla, where the teeth , muscles and temporomandibular joint function in harmony. It is a position of occluso-articular harmony.
Neutral Zone
In dentistry, the neutral zone refers to that space in the oral cavity where the forces exerted by the musculature.of.the tongue are equal and balanced with the.forces exerted by the buccinators.muscle of the cheek.laterally and the orbicularis.oris muscle anteriorly
I will discuss various reference points for face bow.....
Thanks for watching......
If you like to watch my youtube channel..
please click for my channel....... Dr Aaryas Vlogs
https://youtu.be/myAENzQlHjE
The human mandible can be related to the maxilla in several positions in the horizontal plane. Among these centric relation is a significant position, because of its usefulness in relating the dentulous and edentulous mandible to maxilla, where the teeth , muscles and temporomandibular joint function in harmony. It is a position of occluso-articular harmony.
Description :
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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Indian Dental Academy: will be one of the most relevant and exciting training
center with best faculty and flexible training programs for dental
professionals who wish to advance in their dental practice,Offers certified
courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry,
Prosthetic Dentistry, Periodontics and General Dentistry.
00- Revision of occlusion 5th year.pptxAmalKaddah1
The Stomatognathic system
Definitions.
Difference between natural and artificial Occ.
Balanced Occlusion and Factors affecting Balanced O.
Concepts of occlusion (Balanced and Non-balanced Occlusion).
Revision of Complete Denture Occlusion 5th yearAmalKaddah1
Revisions of
Definitions
Differences between natural and artificial dentition
Types of artificial tooth forms
Types of balance
Factors affecting balanced occlusion
Concepts of occlusion
4- Revision >> Concepts of occlusion for 4th year Students.AmalKaddah1
Occlusion for Removable Prosthodontics.
Revision:
What 'occlusion' is and why it is important
Definitions.
Difference between natural and artificial Occlusion.
Types of artificial posterior teeth
Problems with anatomic and non-anatomic teeth
Factors affecting selection of tooth forms.
Rational for Arranging Posterior Teeth in Balanced Occlusion
Contraindications of balanced occlusion.
Types of Balance as Related to Complete Denture
- Lever balance
-Occlusal Balance.
Balanced Occlusion and Factors affecting Balanced Occ. (Third year)
Concepts of occlusion (Balanced and Non balanced Occlusion).
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
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
Functional malocclusion /certified fixed orthodontic courses by Indian dent...Indian dental academy
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
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Split ridge and expansion techniques are effective for the correction of moderately resorbed edentulous ridges in selected cases.
Transverse expansion is based on osseous plasticity obtained by corticotomy. It progressively allows for an adequate transversal intercortical diameter large enough to insert one or several dental implants.
The gap created by sagittal osteotomy expansion undergoes spontaneous ossification, following a mechanism similar to that occurring in fractures.
Hybrid abutments consist of a titanium insert, which is connected to a ceramic mesostructure using a resin cement
These types of abutments have the advantages of both ceramic and titanium abutments, including improved esthetics, optimal biological response, and superior mechanical properties, with no adverse effects on the implant–abutment interface.
The benefits of implant dentistry can be realized only when the prosthesis is first discussed and determined. An organized treatment approach based on the prosthesis permits predictable therapy results. Five prosthetic options postulated by Misch are available in implant dentistry. Three restorations are fixed and vary in the amount of hard and soft tissue replaced; two are removable and are based on the amount and type of support for the restoration. The amount of support required for an implant prosthesis should initially be designed similar to traditional tooth-supported restorations. Once the intended prosthesis is designed, the implants and treatment surrounding this specific
result can be established.
The maxillary sinuses were first illustrated and described by Leonardo Da Vinci in 1489 and later documented by the English anatomist Nathaniel Highmore in 1651.
The maxillary sinus, or antrum of Highmore, lies within the body of the maxillary bone and is the largest and first to develop of the paranasal sinuses.
Shape- a pyramid-shaped cavity; base- adjacent to the nasal wall; apex- pointing to zygoma.
Size- insignificant until eruption of permanent dentition; average dimensions of adult sinus- 2.5–3.5 cm wide, 3.6–4.5 cm tall, and 3.8–4.5 cm deep; estimated volume of approximately 12–15 cm.
Extent- Anteriorly, extends to canine and premolar area. sinus floor usually has its most inferior point near the first molar region.
Reconstruction of a facial defect is a complex modality either surgically or prosthetically, depending on the site, size, etiology, severity, age, and the patient’s expectation. The loss of an auricle, in the presence of an auditory canal, affects hearing, because the auricle gathers sound and directs it into the canal.
Surgical reconstruction is preferable but prosthetic approach may be necessary in some circumstances such as the presence of complex or large defects, requirement of the recurrence control, local or general contraindications of surgery, damaged neighboring tissues due to the radiotherapy, general poor health, failed reconstructive attempts previously made, refusal of the surgery by the patient, high esthetic demands, the desire for a quick recovery and palliatively operated patients.
Nowadays, craniofacial implants are used to support and retain such prostheses. Studies have shown successful retention and stability of auricular prostheses anchored to the temporal bone with titanium implants.
The main concept of osseodensification technique is that the drill designing creates an environment which enhances the initial primary stability through densification of the osteotomy site walls by means of autografting of bone.
Digital Removable Complete Denture—an Overview.pptxNishu Priya
There is a great responsibility for a dentist and a dental technologist to fabricate high-quality removable complete
dentures. Factors, such as a meticulous diagnosis and treatment planning, a personal communication between the
involved persons, and a profound knowledge of the clinical and technical possibilities, should lead to an easy, simple,
cost-effective, and highly satisfying denture fabrication workflow.
The Tall Tilted Pin Hole Placement Immediate Loading.pptxNishu Priya
The Tall Tilted Pin Hole Immediate Loading (TTPHIL) concept has evolved from various ideologies in implantology: basal, pterygoid, and angulated/tilted implants under immediate loading.
To maximize the success of rehabilitation, the TTPHIL technique utilizes the use of long tilted bicortical implants. Longer implants have more bone to implant contact, thus, improving osseointegration.
By engaging the alveolar and nasal cortex, hard tissue augmentation procedures and vital structures in the premaxilla are avoided.
In the posterior maxilla, pterygoid implants are placed.
smile designing. The terms ‘aesthetic zone’ and ‘smile zone’ are commonly used to denote the appearance
of the teeth and smile. This zone has been shown to influence significantly factors
such as social acceptability, self-confidence and professional prospects. It is paramount
to undertake a meticulous assessment of the aesthetic zone during patient examination,
so that you may best determine which features may require addressing while developing
the treatment plan.
Management of tmd symptoms with photobiomodulation therapyNishu Priya
Conservative approaches, such as soft diets, anti-inflammatory drugs and photobiomodulation therapy (PBMT) or low-level laser therapy (LLLT), have been used to manage TMD.
Lasers have proven to be successful in clinical settings and treatments of soft tissues, musculoskeletal pain, bone regeneration, dentinal hypersensitivity, and provide reduction in symptoms and improved function.
The mechanism of action in PBMT is via absorption of light, with deeply penetrating wavelengths ranging from 630 nm to 1300 nm, to stimulate tissues with direct irradiation to achieve analgesic and anti-inflammatory effects.
The output energy in PBMT does not affect skin temperature and is classified as a soft laser, which increases lymphatic flow, reduces edema and prostaglandin E2 (PGE2) and cyclooxygenase (COX) levels.
A systematic review for pain management reported placebo vs LLLT for practical and clinically relevant parameters using 700nm to 1200nm.
Prosthodontic rehabilitation of maxillary defect in a patientNishu Priya
Restoration of maxillectomy defects demand varied modifications in prosthesis fabrication, to make them lighter and well-tolerated by the patient.
Literature suggests the use of various retentive aids for the construction of conventional obturator to improve retention and oral function.
Fabrication of functional complete dentures for edentulous patients who have undergone hemimandibulectomy is a very arduous and demanding endeavor.
The most challenging situation encountered during this procedure is the deviation of the mandible to the resected side. The deviation of the mandible to the resected side is directly proportional to the loss of tissues in the area hemi-mandibulectomy has been performed.
In cases with Cantor and Curtis classes II, III, IV, and V, guide flange prosthesis would be a treatment modality. For guide flange prosthesis to be effective, the sufficient number of posterior teeth that are periodontally sound should be present in the opposite arch.
In patients where reconstruction is not done after resection of the mandible, scar tissue formation occurs over a period of time that stiffens the tissues and worsens prosthetic rehabilitation, leading to compromised treatment planning.
A successful prosthesis comprises an aesthetic restoration, having good functional qualities allowing comfortable and confident use. Absolute success however can only be considered if the histological and morphological normality of the mucosa and deep supporting tissues is maintained.
It is critical to understand the mucosal response to prosthodontic prostheses for the treatment outcome.
The anatomy of the edentulous ridge in the maxilla and mandible is very important for the design of a complete denture. Objective in fabrication of a complete denture is to provide a prosthesis that restores lost teeth and associated structures functionally, anatomically and aesthetically as much as possible with preservation of underlying structures and the knowledge landmarks help us in achieving our objective.
Sterilization and disinfection in prosthodonticsNishu Priya
Routinely dental care professionals are at an increased risk of crossinfection while treating patients. This occupational potential for disease transmission becomes evident initially when one realizes that most human microbial pathogens have been isolated from oral secretions. Because of repeated exposure to the microorganisms present in blood and saliva, the incidence of certain infectious diseases has been significantly higher among dental professionals than observed for the general population.
Introduction
CERAMICS : An inorganic compound with non-metallic prosthesis typically consisting of oxygen and one or more metallic or semi-metallic elements that is formulated to produce the whole part of a ceramic based dental prosthesis. – GPT 7.
The word Ceramic is derived from the Greek word “keramos”, which literally means ‘burnt stuff’, but which has come to mean more specifically a material produced by burning or firing.
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
Prix Galien International 2024 Forum ProgramLevi Shapiro
June 20, 2024, Prix Galien International and Jerusalem Ethics Forum in ROME. Detailed agenda including panels:
- ADVANCES IN CARDIOLOGY: A NEW PARADIGM IS COMING
- WOMEN’S HEALTH: FERTILITY PRESERVATION
- WHAT’S NEW IN THE TREATMENT OF INFECTIOUS,
ONCOLOGICAL AND INFLAMMATORY SKIN DISEASES?
- ARTIFICIAL INTELLIGENCE AND ETHICS
- GENE THERAPY
- BEYOND BORDERS: GLOBAL INITIATIVES FOR DEMOCRATIZING LIFE SCIENCE TECHNOLOGIES AND PROMOTING ACCESS TO HEALTHCARE
- ETHICAL CHALLENGES IN LIFE SCIENCES
- Prix Galien International Awards Ceremony
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
2. CONTENTS
• Definitions
• Chronological changes of definitions of
centric relation
• Theories
• Muscles involved in centric relation
• Factors influencing centric relation records
• Significance of centric relation
• Complications in recording centric
• Complications in recording centric
• Recording of centric relation
• Methods to returde the mandible
• Difficulties in retruding
• Methods of recording centric relation
• Errors
• Conclusion
• References
3. INTRODUCTION
The relationship among occlusion, condylar position and temporomandibular
disorders (TMDs) has been part of an extensive discussion in dentistry.
There is hardly any aspect of clinical dentistry that is not adversely affected
by a disharmony between the articulation of the teeth and the centric
relation position of the temporomandibular joints.
Centric relation (CR) is the most controversial concept in dentistry. The
concept of CR emerged due to the search for a reproducible mandibular
position that would enable the prosthodontic rehabilitation.
This term is derived from the word ‘center’ or ‘center oriented relation’.
4. DEFINITION
S
• CENTRIC RELATION - A maxillomandibular relationship, independent of tooth
contact, in which the condyles articulate in the anterior-superior position against
the posterior slopes of the articular eminences; in this position, the mandible is
restricted to a purely rotary movement; from this unstrained, physiologic,
maxillomandibular relationship, the patient can make vertical, lateral or protrusive
movements; it is a clinically useful, repeatable reference position. (GPT-9)
The definition of centric relation has evolved over the years and with advanced understanding of
mandibular movement it may change again in future
5. • CENTRIC OCCLUSION - The occlusion of opposing teeth when the mandible is in centric
relation; this may or may not coincide with the maximal intercuspal position
• CENTRIC RELATION RECORD - A registration of the relationship of the maxillae to the
mandible when the mandible is in centric relation. The registration may be obtained either
intraorally or extraorally
• TERMINAL HINGE AXIS /TRANSVERSE
HORIZONTAL AXIS –an imaginary line around
which the mandible may rotate within the
sagittal plane
6. CONTROVERSIES REGARDING
CENTRIC RELATION
The rearmost position is relative term which denotes that
the condyles can go backwards as far as the
temporomandibular ligaments would permit without any
strain.
It does not literally means the most retruded position in the
glenoid fossa, since such a position will produce
considerable amount of strain in ligaments and cause pain.
Understanding various terms used in definitions
7. The term Unstrained refers to the strain of the ligaments and not the strain of the
muscles since it’s the ligament that limits the mandibular movements and not the
muscles hence only ligaments can suffer strain if the head of the condyle is taken
posteriorly beyond the centric relation position.
During normal contraction of muscle, strain always occurs. The closing and retruding
muscles are under some degree of strain in centric relation as centric is a power
position.
The rest position of the jaws is the only position where there is a minimum tonic
contraction of the muscles and truly an unstrained position.
8. The most anterior superior position of the condyle is the position used by the head of the condyle when the
mandible is in its retruded position, from where there is an anterior superior bracing of the condyle against
the distal slope of the articular eminence.
Anterior superior bracing against the distal slope of articular eminence is an intra-articular position that cannot
be clinically visualized.
10. 1977
American
Equillibrum
Society
Most anterior and uppermost
position of condyle opposite the
slope of articular eminence
1978 Celenza
1987
American
Equillibrum
Society
Condyle disc assembly braced
superiorly and anteriorly against
the posterior slope of articular
eminence
Revised - Thinnest avascular
portion of the disc in the anterior,
most superior position of dorsal
slope of eminence
Celenza, F. V., and Nasedkin, J. N.: Occlusion: State of the Art. Chicago, 1978, Quintessence
Publishing Co., Inc.
11. MUSCULOSKELETALLY STABLE
POSITION- OKESON
condyles are in their most supero-anterior position in the
articular fossae, resting against the posterior slopes of the
articular fossae with the discs properly interposed.
This is the position the condyles assume when the elevator
muscles are activated with no occlusal influences.
12. THEORIES
MUSCLE
THEORY
LIGAMENT
THEORY
OSTEOFIBER
THEORY
• Defense reflex -- external pterygoid muscles to
contract
halt the jaw
• Ferrein
• Ligaments become tense-- determines the limits of
the retrusive movement.
• Meyer
• Retrusive terminal stop formed by the soft tissues of
the posterior part of the roof of the glenoid fossa.
• Sazier
• Innervated posterior zone of disc provides biofeedback–
retrusive movement
MENISCUS THEORY
Saizar, P.: Centric relation and condylar movement: Anatomic mechanism. J PROSTHET DENT 26~58
13. GNIFICANCE OFCENTRIC RELATION
Bone to bone relation (constant)
Repeatable and recordable and thus
serves as a reliable guide for
developing centric occlusion
Related to the terminal hinge axis , in
centric relation, condyles exhibit pure
rotation without any translation
More definite than vertical relation
since it is independent of tooth
contact
Yurkstas AA, Kapur KK. Factors influencing centric relation records in edentulous mouths. J Prosthet
14. Reference relation:
•The maxillo-mandibular musculature is so
arranged that a patient can easily move his
mandible into centric relation. Thus CR
serves as a reference relationship for
establishing an occlusion.
•When the CR-CO of artificial teeth do not
coincide or a freedom from centric is not
present, the stability of the denture bases is
in jeopardy and the edentulous patient is
subjected to unnecessary pain or discomfort.
•CR is the horizontal reference position of the
mandible that can be routinely assumed by
edentulous patients under the direction of
the dentist. This makes it possible to verify
the relationship of casts on the articulator
when they are mounted in Centric Relation.
15. Functional movements like chewing and swallowing can be carried out since it is the
most unstrained position.
When a bolus of food is prepared for swallowing the teeth attempt to masticate it
with strong muscular force against the bolus condyles following the paths of
movement that the anatomic structure of the joint dictates, i.e., in an upward and
backward direction.
The condyle tries to seat itself in the glenoid fossa as far as it will go by its own
muscular power. If the teeth intervene before this position is reached, there is a lateral
component of force registered upon the teeth which subsequently causes pain in the
temporomandibular region.
The degree of this lateral force is directly proportional to:
1. The amount of force applied by the muscles during mastication
2. The degree the jaw is out of centric relation.
16. CONCEPTS OF CENTRIC RELATION
POSITION
1. Anatomic: Centric relation is the most
retruded relation. A border position is
determined by the ligaments.
2. Pathophysiologic: Centric relation is the
most posterior unstrained jaw relation.
A position that is not a border position
and is established by muscle action.
Douglas Allen Atwood , JPD ;1968;20 ;21 S. David and R.M.J Gray; 2001; BDJ; 191;
235.
1. Anatomically–when the head of the
condyle is against the most superior
part of the distal facing incline of the
glenoid fossa.
2. Conceptual–with the articular disc in
place, when the muscles that support
the mandible are at their most relaxed
and least strained position.
3. Geometrical- with the intra-articular
disc in place, when the head of the
condyle is in terminal hinge axis.
17. CENTRIC RELATION AND
CENTRIC OCCLUSION
Numerous studies have reported that the majority of
patients with a natural dentition show discrepancies
between the occlusal position of the mandible in CR and MI.
This discrepancy is present in at least 90% of dentitions.
In dentulous individuals, occlusion in centric relation is not
and need not be centric occlusion, although it would be
ideal to have centric occlusion at centric relation.
After the removal of teeth, centric occlusion is lost, while
centric relation remains and serves as a reliable guide to
develop centric occlusion in artificial dentures.
When centric occlusion does not coincide or is not identical
with centric relation, the condyles do not remain in their
upper most position in the glenoid fossae, but take a
position either anteriorly or laterally. This referred as
“centric slide”.
18. THE CONCEPT OF LONG CENTRIC
Dawson: freedom to close the mandible either into centric relation or slightly anterior to it
without varying the vertical dimension at the anterior teeth.
Long centric refers to freedom from centric, not freedom in centric. The principal concern
regarding long centric is the restrictive effect that can result from the lingual inclines of the
upper anterior teeth. If no horizontal freedom is provided for a slightly protruded postural
closure, the lower incisal edges will strike the lingual inclines of the upper anterior teeth.
19. KEY ELEMENTS OF THE
PROCEDURE TO ESTABLISH
MYOSTABLIZED CENTRIC RELATION
1. Orthostatic position of the patient and the practitioner
2. Cervical support
3. Head and mandibular stabilization by the practitioner
4. Rotation movement executed by the patient with tactile control of
the practitioner
5. Patient education: perception of the premature contact, creation of
confidence
6. Reproducibility of rotation movements without translation (tactile
sensation)
Myostabilized centric relation November 2011 international journal of stomatology & occlusion medicine 4(3):87-94
20. FACTORSINFLUENCINGCENTRICRELATION
RECORDS
Resiliency of the supporting tissues
Stability of the recording bases
Temporomandibular joint and its associated
neuromuscular mechanisms
Character of the pressure applied in making the
recording
Technique used in making the recording and the
associated recording devices used
Skill of the dentist
Yurkstas AA, Kapur KK. Factors influencing centric relation records in edentulous mouths. J Prosthet
Dent 2005; 93: 305- 10
Health and cooperation of
the patient
Maxillomandibular
relationship
Posture of the patient
Character or size of the
residual alveolar arch
Amount and character of
the saliva
Size and position of the
tongue
22. ETHODSTORETRUDETHEMANDIBLE
• Simplest, easiest and most efficient
• Let your lower jaw relax, pull it back, and
close on your back teeth
RELAXATION
OF JAW
PUSHING
UPPER JAW
• Get the feeling of pushing your upper jaw
out and close your back teeth together
• Automatically pull the lower jaw backward
• Protruding and retruding of mandible –
repeatedly - finger on the point of the
chin - mandible strike its retruded
position
STRETCH AND
RELAX
MOVEMENTS
23. • Tip of tongue - posterior border of the maxillary
record base - close until the rims come into
contact
• Disadvantage : likehood of displacing the
mandibular record base by the action of tongue
RETRUSION
OF
TONGUE
• Gentle tapping of occlusal rims rapidly and repeatedly
retrudes the mandible
• Disadvantage: Difficult to record and patient can
easily tap in a slightly protrusive or lateral position
RAPID
TAPPING OF
THE
OCCLUSAL
RIMS
• Tilting the head backwards - place tension on
the inframandibular muscles and tend to pull
the mandible to a retruded position
• Disadvantage: Insertion and removal of occlusal
rims from mouth is very difficult
HEAD
POSITION
24. SWALLOWING
• Swallowing usually brings the mandible to a
retruded position .
• Unreliable – since person can swallow when
mandible is not completely retruded
• The temporalis muscle - contraction can be felt
when the mandible is in or near retruded position
by placing finger tips on each side of the head.
TEMPORALIS
MUSCLE CHECK
• Total relaxation of the patient on the chair
automatically brings mandible to retruded
position
GENERALIZED
RELAXATION
OF THE
PATIENT
Boucher’s Prosthodontic Treatment for Edentulous patients.9th
25. POSTURAL RELAXATION OF THE
PATIENT
Pure hinge axis movement imposes an important
decrease of postural muscular activity, both cervical and
mandibular.
Therefore it is essential to offer occipital support to the
patient in order to relax the cervical muscles which are
maintaining head position.
It is important to observe the patient’s head position
without any flexure or extension of the cervical spine.
The aim is to achieve a natural head position.
To make it easier for the practitioner the patient is
placed in a chair inclined approximately 30° from the
horizontal.
26. COMPLICATIONSINRECORDING
CENTRIC
• One joint can be displaced downward by
uneven pressure (record are made)
• Yet the condyles be in their most retruded
position
• Situation on articulator – cannot occur - a
deflective occlusal contact - instability, soreness
and resorption
Structure
of TMJs
• Hanau
• Uneven resiliency in the soft tissues - the
mucosa and tissue of TMJs
• Undue pressure - excessive displacement of soft
tissues
Realeff
effect
Boucher’s Prosthodontic Treatment for Edentulous patients.9th edition,277-291
28. BIOLOGICALPROBLEM
Denture wearers with marked attrition of posterior
teeth
Edentulous for a long time
Patient having only anterior teeth
• Lack of muscle co-ordination
• Lack of synchronization between the
protruding and retruding muscles due
to “HABITUAL” eccentric jaw positions
adopted by the patient to
accommodate malocclusion
Involuntary forward
movement of the
mandible.
Causes
29. PSYCHOLOGICALPROBLEM
• Patient and dentist
• The more the dentist – irritated by – apparent inability of the patient to retrude
the mandible - more confused the patient
• The dentist must be prepared to spend adequate time securing the CR record
• Poorly fitting of base plates
• Displacement of the soft tissue (excessive pressure during registration)
• Tissue depth is uneven
MECHANICALPROBLEM
30. RECORDING THE CENTRIC
RELATION
MINIMUM CLOSING PRESSURE HEAVY CLOSING PRESSURE
Two basic concepts
Record - minimal closing
pressures - tissue supporting
the bases will not be displaced
Objective - opposing teeth to
touch uniformly and
simultaneously at their first
contact
Record - heavy closing pressure -
tissues under the recording bases
will be displaced
Objective - same displacement of
the soft tissue. Thus occlusal force
will be evenly distributed over the
supporting residual ridges
Minimal closing pressures –
produce best result for most
patients
32. Physiological or
inter-occlusal check
record method
Functional methods
HEARTWELL
Chew-in technique
a) Needle House technique
b) Patterson technique
Graphic methods
a) Intraoral devices
b) Extraoral devices
33. PHYSIOLOGICMETHOD
• Proprioceptive impulse of patient
• Kinethetic sense of mandibular movement
• Visual acuity and sense of touch
Based on
• Tactile or interocclusal check record
method
• Pressureless method
• Pressure method
Types
34. TACTILEOR INTEROCCLUSALCHECKRECORD
METHOD
• Phillip Pfaff – 1756
• Also known as the 'mush', 'biscuit' or 'squash bite‘
Indications:
Abnormally related jaw
Supporting tissues that are excessively displaceable
Large tongue
Uncontrollable or abnormal mandibular movements
35. YEAR AUTHOR MATERIAL AND METHOD
1954 Brown Repeated closure into softened wax rims
1957 Greene Patients hold their jaws apart for 10 seconds to
fatigue the muscles Snap the rims together.
Made lines in the rims to orient them after removal from the
mouth.
Gradually, these procedures evolved - Small amounts of wax,
compound, plaster and Zinc-Oxide Eugenol Impression paste
were placed between the occluding rims equalize the pressure
of vertical contact
MATERIALS
36. YEAR AUTHOR MATERIAL AND METHOD
1932 Schuyler Viscosity – not uniform - uneven pressure transmitted to the
record
Bases - disharmony of occlusion.
Modeling compound - softened more evenly, cools slower,
and doesn’t distort as much as wax.
1939 Wright • Factors
-Resiliency of tissue
-Saliva film
-Fit of bases
•Pressure
applied
ZERO
PRESSURE
1955 Trapozzano Wax “Check-bite method most prefered technique
WHICH MATERIAL IS BEST?
37. YEAR AUTHOR MATERIAL AND METHOD
1932 Schuyler Consider a record secured on compound or wax occluding
Rims sufficiently free from error to compete with
the restorations without additional checks
1954 Simpson Wax records were unscientific
Gysi Tested this method on manikins and never got the same
recording twice with wax or compound,
He concluded that the uneven cooling of the material
produced distortion
CRITISICM
38. TATICOR PRESSURELESSMETHOD
• Nick and Notch method
• Nick - Anterior -
prevent lateral
movement
• Notch – Posterior -
anteroposterior
movement
39. FUNCTIONALMETHOD
Utilize the functional movements of the jaws to record the centric relation.
The patient is asked to do the movements in
• Protrusion
• Retrusion
• Right lateral
• Left lateral
Types:
-Needles House Method
-Patterson method
-Mayer’s method
40. AUTHOR MATERIALS
Greene Plaster and pumice mixture
Needles Mounted three studs on
maxillary rims
Patterson Corborandum and plaster
mixture
Meyer Soft wax occlusal rims, tin foil
placed
Boose Gnathodynomometer
Shanahan Cones of soft wax
HISTORICAL
BACKGROUND
41. • Earliest graphic recordings were based on studies of
mandibular movements by Balkwill in 1866.
• The intersection of the arcs produced by the right and left
condyles formed the apex of what is known as GOTHIC
ARCH TRACING
• “Gothic” name originate from ancient Gothic
people’s houses (Barbarian tribes of Rome) GOTHIC
ARCH TRACING
GRAPHIC
METHOD
43. INTRAORALTRACINGS
• A central bearing and tracing device.
• Pointed screw in bearing
• Tracing device - maxillary rim
• Plate mounted - mandibular rim.
• Plate is covered with a marking substance.
• The central bearing pin is connected to the proper
vertical relation
• Patient -lateral and protrusive movements.
• Gothic arch form is traced on the plate.
46. • Bearing-tracing device is strong enough to
resist biting pressures and can be held in
position by means of a locking disk
• More accurate
ADVANTAGES
• Relative difficulty in visualizing the tracing
• Since the intraoral tracings are small, it will be
difficult to find the true apex.
DISADVANTAGES
47. EXTRAORALTRACINGS
• Similar to intra oral tracer.
• It has same central bearing device attached to occlusal
rims & another attachment projects outside the mouth.
• Extra oral tracing pointer & recording plates are attached
to these projections.
• Size of tracing pattern is larger so apex can be
identified easily
48.
49.
50. • Larger than its intraoral counterpart - apex is
more discernible
• Visible - Patient can be guided and directed more
intelligently during the mandibular movements
• The stylus can be observed in the apex of the
tracing during the process of injecting plaster
ADVANTAGES
The lips and cheek may interfere as recording
device is placed extraorally
DISADVANTAGE
S
51. PANTOGRAPHY
Used clinically to measure mandibular movement
• Graphic record in three planes
Types-
• Mechanical (by McCollum and Staurt)
• Electronic
It has six tracing platforms and styli to graph gothic
arch as well as jaw and condylar movements.
A vertical and a horizontal tracing table are located
on each side of the patient's face overlying the TM
joints, and a pair of horizontal tables,
approximately at the level of the plane of occlusion,
is located below the eyes.
The tracing procedure is carried out to record
terminal hinge axis as the reference point and
lateral border paths are traced whilst the jaw is
52. AUTHOR METHODS
Gysi (1929) Gothic tracing technique - five-degree error
wax and compound bites - 25-degree error
Brown needle point tracing is unreliable and recommends repeated closures
into wax under close observations
National Society
of Denture
Prosthetics
Needle point tracing - both scientific and
practical. This society recognizes no other means of
verifying centric jaw relationships
Payne 1955 Intra-oral tracer - difficult to see and does not work as well where flat ridges or
flabby tissue occur.
Extra-oral tracing
provides visibility but retain the other
difficulties if central bearing plates are
used.
The more equipment we put into the mouth, the more difficult it is for the
patient
Kingery(1952) Several drawbacks in the use of the central bearing point
central bearing point allows for no control over the amount of closing pressure
applied by the
COMPARATIVE EVALUATION OF
DIFFERENT METHODS
53. Kapur et al -The intra-oral and extra-oral tracing procedures were more consistent as
compared to the wax registration method.
- In patients with flabby ridges, the intra-oral and extra-oral tracing
procedure became less
consistent as compared to the wax registration method.
Thakur M Gothic arch method- more technique sensitive and required greater
chair-side time both for the dentist as well as for the patient.
-Incorporation of errors due to mishandling of the device
-fatigue of muscles and jaws from repeated efforts to guide the mandibular
movements
conventional method > gothic arch
Abbad Intraoral digital tracing technique > conventional intraoral tracer technique.
Consistency of reproducibility - supine position is significantly higher than
upright position.
Thakur M, Jain V, Parkash H, Kumar P.A comparative evaluation of static and functional methods for recording
centric relation and condylar guidance: A clinical study. J Indian Prosthodont Soc. 2012;12:175–81
54. ARROW HEAD TRACING
• A planar tracing that resembles an arrowhead or gothic arch made by means of
a device attached to the opposing arches; the shape of the tracing depends on
the location of the marking point relative to the tracing table, i.e., In the incisal
region as opposed to posteriorly; the apex of a properly made anterior tracing is
considered to indicate the centric relation position (GPT-9)
• Measured across a single plane
55. Classical,
pointed
form
• Seen as a well-defined apex with a symmetrical left
and right lateral component
• The symmetry indicates an undisturbed movement
sequence in the joints and uniform muscle guidance
• It reflects a healthy TMJ
Classical flat
form
• Similar to typical arrow point
• Except that it has more obtuse left and right lateral
tracings.
• This type of arrow point signifies a marked lateral
movement of
Condyle in the fossa.
Weak Gothic
arch
tracing
• A lax and negligent performance of the
movements.
• Apex - Round Form
• The registration must be repeated:
• Stronger movements must be demanded
from the patient
56. Asymmetrical
form
• The left and right lateral tracings meet in an arrow
point; however their inclination to the protrusive
path is not symmetrical.
• One of the lateral tracing is shorter.
• Indicates an inhibition of the forward movement;
either in the left or right joint.
Miniature
form
• Similar to the typical arrow point
• Extension of tracing is very limited.
• This can be due to:
-restricted mandibular movements
- improper seating of record bases
- painfully fitting record bases during registration.
• Indication of a long period of edentulousness with
an inhibition in condylar movements
Vertical line
beyond arrow
point (Dorsally
Extended)
• By forcible retraction or pushing of the
mandible.
• Gothic arch was obtained with a protruded
mandible
• An artifact - forward displacement of upper
occlusal rim or backward dislodgement of
57. Double Arrow
Point
• Record of habitual and retruded centric relation.
• Allow patient training and repeat till a single gothic
arch is obtained.
• It is also seen when vertical dimension is altered
during registration
Interrupted
Gothic
Arch
• Break or loss of continuity of lateral incisal path of
Gothic arch.
• This happens due to posterior interference at the
heels of occlusal
rims during lateral movements.
• Check for posterior clearance before recording.
Atypical
Form
• Protrusive component does not meet at apex but
on one of the
lateral path.
• This may happen in dentulous because of a faulty
muscular pattern due to par functional habits like
bruxism.
• It is also seen in very old edentulous patients, who
59. POSITIONALERRORS
• Failure of the operator in his registration of the correct horizontal
relationship
• Failure of the operator to record equalized vertical contact
• Application of excessive closure pressure by the patient at the time of
recording
• Changes in the supporting area
60. TECHNICAL
ERRORS
• Ill fitting occlusion rims: if record bases
are not stable
• Indiscriminate opening and closing of the occluding device (articulator)
• The slight shifting teeth which occurs between the stage of final
arrangement in wax and the transfer to a permanent base material
• A movement by the tooth or several teeth either horizontally, or
vertically, introduces an error
62. CONCLUSION
• Centric relation is a most reproducible, reliable, repeatable, recordable, and
reference position.
• Centric relation should coincide with centric occlusion otherwise will affect the
stability of the dentures.
• Correct recoding of horizontal jaw relation, verified for accuracy as it affects the
health, comfort, function of the muscles, and Temporomandibular joint.
• It is apparent from dental literature that with many opinions and much confusion
concerning centric relation records, a certain technique might be required for an
unusual situation or a problem patient. In the final analysis, skill of the dentist and
co-operation of the patient are probably the most important factors in securing an
accurate Centric Relation record.
63. REFERENCES
• Celenza, F. V., and Nasedkin, J. N.: Occlusion: State of the Art. Chicago, 1978,
Quintessence Publishing Co., Inc.
• Saizar, P.: Centric relation and condylar movement: Anatomic mechanism. J
PROSTHET DENT 26~581, 1971.
• Boucher’s Prosthodontic Treatment for Edentulous patients.9th edition,277-29
• Yurkstas AA, Kapur KK. Factors influencing centric relation records in edentulous
mouths. J Prosthet
Dent 2005; 93: 305- 10
• Squire, BE : Joint Compliance – Its role in centric relation. J Gnath 3:61,1984
• E.G.R. Solomon, Manual of maxilla-mandibular relations
64. • Sharry JJ Complete denture prosthodontics 3rd edition
• Heartwell CM,Rahn AO Syllabus of complete dentures 4th edition
• Winkler’s Essentials of complete denture prosthodontics 2nd edition
• Posselt, Franzen. Registration of the condyle path nclination by intraoral wax
records: variations in three instruments. J Prosthet Dent 1960;10:441-54.
• Badel T, Panduric J, Kraljevic S, Dulcic N. Checking the occlusal relationships of
complete dentures via a remount procedure. Int J Periodontics Restorative Dent
2007; 27:181192.
• Gutowski A. Remounting and occlusal adjustment of complete dentures. J Gnathol
1990;9:9–22.
• Myostabilized centric relation November 2011 international journal of
stomatology & occlusion medicine 4(3):87-94