This document discusses the debate around whether orthodontists should mount dental casts on an articulator. While articulators are useful for other dental specialties, their validity in orthodontics is equivocal. Supporters argue that articulators allow detection of minor occlusal discrepancies and aid in achieving ideal condyle position. However, others argue that articulators are unnecessary given tolerance for occlusal discrepancies and lack of evidence that they improve outcomes. The document examines evidence on both sides but ultimately argues against the routine use of articulators in orthodontics.
This study used magnetic resonance imaging (MRI) to evaluate condylar position in the glenoid fossae of 19 subjects under three different bite registration conditions: centric occlusion, centric relation, and Roth power centric relation. The results showed that (1) all measurements had large variations and no statistically significant differences between the bite registrations, and (2) most condyles (87%) were concentric in the anteroposterior plane under all three registrations. The study concludes that positioning the condyles in specific positions using different bite registrations is not supported as a preventive measure or diagnostic/treatment tool for temporomandibular disorders.
Subjective classification and objective analysis of the mandibular dental arc...EdwardHAngle
Our objective was to evaluate the relationship between subjective classification of dental-arch shape, objective analyses via arch-width measurements, and the fitting with the fourth-order polynomial equation.
The document discusses various methods for predicting facial growth, including Johnston's grid method, Bjork's structural method, and Fishman's maturational method. It compares the accuracy of short-term and long-term predictions between these methods. While growth prediction remains difficult due to variability, the maturationally oriented Fishman method was found to be generally superior to chronologically based methods like Johnston's grid and Ricketts analysis. No single method can accurately predict growth for all individuals, especially those with extreme growth patterns.
Transverse growth of the maxilla and mandible in untreated girls with low, av...EdwardHAngle
The purpose of this study was to investigate maxillary and mandibular transverse growth in
untreated female subjects with low, average, and high mandibular plane angles longitudinally from ages 6 to 18.
New insights on age related association between nasopharyngeal airway clearan...EdwardHAngle
This document summarizes a study that evaluated the relationship between adenoid hypertrophy (enlarged adenoids) and facial morphology in children. The study examined 200 children referred for suspected adenoid obstruction, dividing them into two age groups and four subgroups based on facial divergence. Measurements were made from lateral cephalograms to assess airway clearance and facial morphology. Results found smaller airway measurements and more divergent facial patterns in children aged 6 and under and those with severe facial divergence. The findings suggest earlier airway clearance may be needed in severely affected young children to prevent irreversible facial changes.
This document discusses the biological rationale for early treatment of dentofacial deformities. It addresses the growth potential of sutures and condylar cartilage, implications for modifying facial growth, and future directions. Specifically:
1) Sutures and condylar cartilage have stem cells that allow growth throughout life and can be influenced by biomechanical factors, making modification of facial growth possible.
2) The best time to intervene is debated, but growth is most modifiable early in development. Treatment effects depend on available stem cells and growth factor expression, which vary over time.
3) Future work will integrate developmental biology principles with treatment, using genetics to assess growth potential and possibly targeting growth factors for more
Malposition of unerupted mandibular second premolar in children with cleft li...EdwardHAngle
Objective: To determine whether distoangular malposition of the unerupted mandibular second
premolar (MnP2) is more frequent in children with unilateral clefts of the lip and palate.
Materials and Methods: This retrospective study examined panoramic radiographs from 45 patients
with unilateral clefts of the lip and/or palate who had no previous orthodontics. A control
sample consisted of age- and sex-matched patients. The distal angle formed between the long
axis of MnP2 and the tangent to the inferior border was measured. The mean, standard deviation,
and range were calculated for the angles measured in the cleft and the control groups. The
significance of the differences between the means was evaluated by the paired t-test. The angles
of the cleft and noncleft sides were also measured and compared.
Results: The mean inclination of the MnP2 on the cleft side was 73.6°, compared with 84.6° in
the control group. This difference was highly significant statistically (P < .0001). The difference
in angles from the cleft and noncleft sides was 0.7°, not statistically significant. A significant association
was found between clefting and distoangular malposition of the developing MnP2, suggesting
a shared genetic etiology. This association is independent of the clefting side, ruling out
possible local mechanical effects.
Conclusion: Clinicians should be aware of the potential for anomalous development of MnP2 in
children with clefts.
This document provides details on a proposed study to estimate stature from measurements of anterior mandibular teeth. The study aims to derive a formula for stature estimation using dental measurements and determine if there are sex-based differences. The methodology section outlines that measurements will be taken from 180 subjects aged 21-30 years with stable teeth. Measurements collected will include actual height, dental arch, chord, and half intercanine distance. Statistical analysis will then evaluate the accuracy of estimated statures compared to actual heights.
This study used magnetic resonance imaging (MRI) to evaluate condylar position in the glenoid fossae of 19 subjects under three different bite registration conditions: centric occlusion, centric relation, and Roth power centric relation. The results showed that (1) all measurements had large variations and no statistically significant differences between the bite registrations, and (2) most condyles (87%) were concentric in the anteroposterior plane under all three registrations. The study concludes that positioning the condyles in specific positions using different bite registrations is not supported as a preventive measure or diagnostic/treatment tool for temporomandibular disorders.
Subjective classification and objective analysis of the mandibular dental arc...EdwardHAngle
Our objective was to evaluate the relationship between subjective classification of dental-arch shape, objective analyses via arch-width measurements, and the fitting with the fourth-order polynomial equation.
The document discusses various methods for predicting facial growth, including Johnston's grid method, Bjork's structural method, and Fishman's maturational method. It compares the accuracy of short-term and long-term predictions between these methods. While growth prediction remains difficult due to variability, the maturationally oriented Fishman method was found to be generally superior to chronologically based methods like Johnston's grid and Ricketts analysis. No single method can accurately predict growth for all individuals, especially those with extreme growth patterns.
Transverse growth of the maxilla and mandible in untreated girls with low, av...EdwardHAngle
The purpose of this study was to investigate maxillary and mandibular transverse growth in
untreated female subjects with low, average, and high mandibular plane angles longitudinally from ages 6 to 18.
New insights on age related association between nasopharyngeal airway clearan...EdwardHAngle
This document summarizes a study that evaluated the relationship between adenoid hypertrophy (enlarged adenoids) and facial morphology in children. The study examined 200 children referred for suspected adenoid obstruction, dividing them into two age groups and four subgroups based on facial divergence. Measurements were made from lateral cephalograms to assess airway clearance and facial morphology. Results found smaller airway measurements and more divergent facial patterns in children aged 6 and under and those with severe facial divergence. The findings suggest earlier airway clearance may be needed in severely affected young children to prevent irreversible facial changes.
This document discusses the biological rationale for early treatment of dentofacial deformities. It addresses the growth potential of sutures and condylar cartilage, implications for modifying facial growth, and future directions. Specifically:
1) Sutures and condylar cartilage have stem cells that allow growth throughout life and can be influenced by biomechanical factors, making modification of facial growth possible.
2) The best time to intervene is debated, but growth is most modifiable early in development. Treatment effects depend on available stem cells and growth factor expression, which vary over time.
3) Future work will integrate developmental biology principles with treatment, using genetics to assess growth potential and possibly targeting growth factors for more
Malposition of unerupted mandibular second premolar in children with cleft li...EdwardHAngle
Objective: To determine whether distoangular malposition of the unerupted mandibular second
premolar (MnP2) is more frequent in children with unilateral clefts of the lip and palate.
Materials and Methods: This retrospective study examined panoramic radiographs from 45 patients
with unilateral clefts of the lip and/or palate who had no previous orthodontics. A control
sample consisted of age- and sex-matched patients. The distal angle formed between the long
axis of MnP2 and the tangent to the inferior border was measured. The mean, standard deviation,
and range were calculated for the angles measured in the cleft and the control groups. The
significance of the differences between the means was evaluated by the paired t-test. The angles
of the cleft and noncleft sides were also measured and compared.
Results: The mean inclination of the MnP2 on the cleft side was 73.6°, compared with 84.6° in
the control group. This difference was highly significant statistically (P < .0001). The difference
in angles from the cleft and noncleft sides was 0.7°, not statistically significant. A significant association
was found between clefting and distoangular malposition of the developing MnP2, suggesting
a shared genetic etiology. This association is independent of the clefting side, ruling out
possible local mechanical effects.
Conclusion: Clinicians should be aware of the potential for anomalous development of MnP2 in
children with clefts.
This document provides details on a proposed study to estimate stature from measurements of anterior mandibular teeth. The study aims to derive a formula for stature estimation using dental measurements and determine if there are sex-based differences. The methodology section outlines that measurements will be taken from 180 subjects aged 21-30 years with stable teeth. Measurements collected will include actual height, dental arch, chord, and half intercanine distance. Statistical analysis will then evaluate the accuracy of estimated statures compared to actual heights.
This case series examines a new surgical technique for regenerating interimplant papillae using subepithelial connective tissue grafts. 10 patients with missing papillae between implant restorations received the new procedure involving buccal and palatal incisions made away from the papilla to preserve blood supply, and tunneling performed with a specialized instrument. The papillae scores improved on average from 0.8 to 2.4 after 16 months, demonstrating regeneration of the papillae over 11-30 months. However, long-term studies are still needed to validate the technique and outcomes.
This document discusses a case study of using unilateral sagittal split ramus osteotomy (SSRO) with an interpositional iliac bone graft to correct facial asymmetry in a 27-year old female patient. The patient presented with flatness on the right side of her face and mandible. Clinical and radiographic examinations revealed a decrease in the mediolateral distance of the right mandibular ramus compared to the left. Unilateral SSRO was performed on the right side, and a cancellous iliac bone graft was interpositioned between the proximal and distal segments to restore symmetry. Rigid fixation with a bent plate was used to stabilize the graft and maintain thickness. At follow-up, the procedure had
This study compared the effectiveness of Hawley retainers and two protocols for vacuum-formed retainers (VFRs) in maintaining orthodontic treatment results. 90 patients were randomly assigned to receive either a Hawley retainer, VFRs worn for 4 months full-time then nightly, or VFRs worn for 1 week full-time then nightly. Models at debond and 4 and 8 months post-treatment showed the Hawley group had significantly greater loss of upper arch length and increased crowding compared to the VFR groups, though lower arch measurements were similar. Both VFR protocols were more effective than Hawleys in maintaining the upper arch, and 4 months full-time wear provided better lower incis
1) The document summarizes research on early orthodontic intervention for patients with tooth-size discrepancies. It focuses on using rapid maxillary expansion (RME) in the mixed dentition stage to correct crowding issues.
2) Long-term studies found that RME followed by fixed appliances resulted in clinically significant increases in maxillary and mandibular arch width even 5+ years post-treatment. RME also had benefits like improving nasal breathing.
3) For patients with mild-moderate crowding, RME combined with other approaches like Schwarz appliances in early treatment resulted in increased arch widths that were maintained long-term. RME was found to be an effective option for treating mixed dentition patients
Craniofacial growth in untreated skeletal class i subjects with low, average,...EdwardHAngle
The dental measurements showed few changes with growth in all groups. In terms of skeletal measurements from ages 9 to 18, similar growth changes were found between the sexes in most angular measurements, but males had larger values in linear measurements than females.
This document contains a registration form for a dissertation topic comparing methods of determining condylar guidance. [1] The study will compare values obtained from interocclusal records in a semi-adjustable articulator to those obtained by tracing panoramic radiographs in 20 dentulous and 20 edentulous patients. [2] Ethical clearance has been obtained and the study will involve making interocclusal records and taking panoramic radiographs to measure condylar guidance in participants. [3]
Principles of orthognathic management of dentofacial deformitiesWaheed Murad
This document outlines the principles and process of orthognathic management for dentofacial deformities. It involves an initial joint orthodontic-orthognathic assessment including patient history, clinical examination, documentation, dental casts, and radiographs to evaluate the skeletal and dental deformities. A treatment plan is developed which may involve presurgical orthodontics, surgical correction using procedures like LeFort osteotomies or bisagital split osteotomies, and postsurgical orthodontics and care. The goal is to carefully plan and coordinate orthodontic and surgical treatment to correct dentofacial deformities.
This document discusses surgical techniques for reconstructing auricular defects of different sizes. It summarizes the experience of surgeons in treating 75 patients over 10 years. For defects less than one-fourth the vertical ear size, primary closure is sufficient. For larger defects up to three-fourths the size, a reversed retroauricular flap is often used successfully. For defects exceeding three-fourths the size, an implant-retained prosthesis is preferred. The location, size, and tissue involved in the defect, as well as the patient's condition, determine the most appropriate reconstruction method.
Modification of Distal Shoe- A Systematic Review & Meta AnalysisDrHeena tiwari
The document summarizes a systematic review of modifications to the distal shoe space maintainer. It analyzes 6 studies on modified distal shoe designs. The studies showed that the modifications provided stability, adjustability, and were well-accepted by patients. However, the quality of the studies was low and conclusions about the efficacy of the modifications were inconclusive due to a lack of clear reporting on outcomes. Further high-quality research is needed to establish the effectiveness of modified distal shoe space maintainers.
Commercially available archwire forms compared with normal dental arch forms ...EdwardHAngle
This study compared the widths of 20 commercially available preformed archwires to the widths of natural dental arches in 30 subjects with ideal occlusions. The study found that the preformed archwires were significantly narrower than the natural dental arches at both the canine and molar levels. Specifically, 14 archwires fell within 1 standard deviation of the mean canine width, but only 7 fell within 1 standard deviation of the mean molar width. The variations in current preformed archwire forms do not entirely correspond to the diversity of normal arch forms.
This document describes a case report of a 23-year-old male patient who presented with facial asymmetry and flattening of the right side of the face due to childhood temporomandibular joint ankylosis. Treatment involved a two-stage procedure, first using orthognathic surgery (Le Fort I osteotomy) to correct occlusal cant, followed by orthomorphic surgery (extended lateral sliding genioplasty) 6 months later to correct the facial asymmetry and underdevelopment of the mandible. The combination of orthognathic and orthomorphic surgery successfully achieved functional and aesthetic goals by correcting the jaw deviation and restoring facial symmetry.
The document summarizes discussions from an early treatment symposium regarding the treatment of skeletal open bite malocclusions. It addresses questions about defining early treatment, the differences between dental and skeletal open bites, benefits of early treatment for hyperdivergent open bites, and appropriate treatment approaches. The optimal treatment is said to be beginning between ages 7-8 and includes rapid maxillary expansion, headgear, and light muscle exercises to control vertical growth and encourage counterclockwise mandibular rotation. Early intervention is advocated to modify growth and prevent needing future surgery.
Gingival recession—can orthodontics be a cure? evidence from a case presentationEdwardHAngle
A 35-year-old woman presented with severe gingival recession and a unilateral Class II malocclusion. Her treatment plan involved orthodontic correction of the malocclusion using brackets that torqued roots more onto the bone. It also involved changing her dental hygiene methods to use an oscillating toothbrush gently. After 28 months of orthodontic treatment, her malocclusion was corrected and her gingival recession improved without needing grafting. Three months later, her teeth had settled well into their new positions.
Effects of rapid palatal expansion on the sagittal and vertical dimensions of...EdwardHAngle
The purpose of this study was to use cone-beam computed tomography imaging to examine the skeletal and dental changes in the sagittal and vertical dimensions after rapid palatal expansion.
The document summarizes a journal club presentation on a 3-year study evaluating the clinical performance of short expandable dental implants in highly atrophic alveolar bone. The study found a 94.7% implant success rate in the mandible and 83.6% in the maxilla over a mean follow-up of 42.6 months, with median 3-year crestal bone changes demonstrating maintenance of peri-implant alveolar bone. The conclusion was that the short expandable implant system provided reliable oral rehabilitation, especially for elderly patients with difficult implantation conditions.
This document provides an overview of a book titled "Evidence-Based Decision Making: A Translational Guide for Dental Professionals". The book teaches dental professionals the essential skills of evidence-based decision making, including how to form clinical questions based on a patient case, search efficiently for relevant evidence, critically appraise evidence, apply evidence to patient care, and evaluate their EBDM performance. Each chapter contains objectives, activities, and case examples to reinforce skills. The goal is for readers to complete the full EBDM process for different clinical question types.
Segmental Fractures of the Forearm- Outcome Analysis of Various Management St...iosrjce
IOSR Journal of Dental and Medical Sciences is one of the speciality Journal in Dental Science and Medical Science published by International Organization of Scientific Research (IOSR). The Journal publishes papers of the highest scientific merit and widest possible scope work in all areas related to medical and dental science. The Journal welcome review articles, leading medical and clinical research articles, technical notes, case reports and others.
Mandibular arch form the relationship between dental and basal anatomyEdwardHAngle
We investigated mandibular dental arch form at the levels of both the clinically relevant application points of the orthodontic bracket and the underlying anatomic structure of the apical base. The correlation of both forms was evaluated and examined to determine whether the basal arch could be used to derive a standardized clinical arch form.
1) The document argues against routinely mounting dental casts on articulators for orthodontic treatment, as there is no convincing evidence that it improves outcomes.
2) While articulators may help elucidate jaw relationships, using them routinely appears perfunctory given that factors like occlusion and condyle position are no longer considered primary causes of temporomandibular disorders.
3) The paradigm around temporomandibular disorders has shifted from a dental model to a biopsychosocial one, and orthodontics is now considered temporomandibular disorders neutral.
This case series examines a new surgical technique for regenerating interimplant papillae using subepithelial connective tissue grafts. 10 patients with missing papillae between implant restorations received the new procedure involving buccal and palatal incisions made away from the papilla to preserve blood supply, and tunneling performed with a specialized instrument. The papillae scores improved on average from 0.8 to 2.4 after 16 months, demonstrating regeneration of the papillae over 11-30 months. However, long-term studies are still needed to validate the technique and outcomes.
This document discusses a case study of using unilateral sagittal split ramus osteotomy (SSRO) with an interpositional iliac bone graft to correct facial asymmetry in a 27-year old female patient. The patient presented with flatness on the right side of her face and mandible. Clinical and radiographic examinations revealed a decrease in the mediolateral distance of the right mandibular ramus compared to the left. Unilateral SSRO was performed on the right side, and a cancellous iliac bone graft was interpositioned between the proximal and distal segments to restore symmetry. Rigid fixation with a bent plate was used to stabilize the graft and maintain thickness. At follow-up, the procedure had
This study compared the effectiveness of Hawley retainers and two protocols for vacuum-formed retainers (VFRs) in maintaining orthodontic treatment results. 90 patients were randomly assigned to receive either a Hawley retainer, VFRs worn for 4 months full-time then nightly, or VFRs worn for 1 week full-time then nightly. Models at debond and 4 and 8 months post-treatment showed the Hawley group had significantly greater loss of upper arch length and increased crowding compared to the VFR groups, though lower arch measurements were similar. Both VFR protocols were more effective than Hawleys in maintaining the upper arch, and 4 months full-time wear provided better lower incis
1) The document summarizes research on early orthodontic intervention for patients with tooth-size discrepancies. It focuses on using rapid maxillary expansion (RME) in the mixed dentition stage to correct crowding issues.
2) Long-term studies found that RME followed by fixed appliances resulted in clinically significant increases in maxillary and mandibular arch width even 5+ years post-treatment. RME also had benefits like improving nasal breathing.
3) For patients with mild-moderate crowding, RME combined with other approaches like Schwarz appliances in early treatment resulted in increased arch widths that were maintained long-term. RME was found to be an effective option for treating mixed dentition patients
Craniofacial growth in untreated skeletal class i subjects with low, average,...EdwardHAngle
The dental measurements showed few changes with growth in all groups. In terms of skeletal measurements from ages 9 to 18, similar growth changes were found between the sexes in most angular measurements, but males had larger values in linear measurements than females.
This document contains a registration form for a dissertation topic comparing methods of determining condylar guidance. [1] The study will compare values obtained from interocclusal records in a semi-adjustable articulator to those obtained by tracing panoramic radiographs in 20 dentulous and 20 edentulous patients. [2] Ethical clearance has been obtained and the study will involve making interocclusal records and taking panoramic radiographs to measure condylar guidance in participants. [3]
Principles of orthognathic management of dentofacial deformitiesWaheed Murad
This document outlines the principles and process of orthognathic management for dentofacial deformities. It involves an initial joint orthodontic-orthognathic assessment including patient history, clinical examination, documentation, dental casts, and radiographs to evaluate the skeletal and dental deformities. A treatment plan is developed which may involve presurgical orthodontics, surgical correction using procedures like LeFort osteotomies or bisagital split osteotomies, and postsurgical orthodontics and care. The goal is to carefully plan and coordinate orthodontic and surgical treatment to correct dentofacial deformities.
This document discusses surgical techniques for reconstructing auricular defects of different sizes. It summarizes the experience of surgeons in treating 75 patients over 10 years. For defects less than one-fourth the vertical ear size, primary closure is sufficient. For larger defects up to three-fourths the size, a reversed retroauricular flap is often used successfully. For defects exceeding three-fourths the size, an implant-retained prosthesis is preferred. The location, size, and tissue involved in the defect, as well as the patient's condition, determine the most appropriate reconstruction method.
Modification of Distal Shoe- A Systematic Review & Meta AnalysisDrHeena tiwari
The document summarizes a systematic review of modifications to the distal shoe space maintainer. It analyzes 6 studies on modified distal shoe designs. The studies showed that the modifications provided stability, adjustability, and were well-accepted by patients. However, the quality of the studies was low and conclusions about the efficacy of the modifications were inconclusive due to a lack of clear reporting on outcomes. Further high-quality research is needed to establish the effectiveness of modified distal shoe space maintainers.
Commercially available archwire forms compared with normal dental arch forms ...EdwardHAngle
This study compared the widths of 20 commercially available preformed archwires to the widths of natural dental arches in 30 subjects with ideal occlusions. The study found that the preformed archwires were significantly narrower than the natural dental arches at both the canine and molar levels. Specifically, 14 archwires fell within 1 standard deviation of the mean canine width, but only 7 fell within 1 standard deviation of the mean molar width. The variations in current preformed archwire forms do not entirely correspond to the diversity of normal arch forms.
This document describes a case report of a 23-year-old male patient who presented with facial asymmetry and flattening of the right side of the face due to childhood temporomandibular joint ankylosis. Treatment involved a two-stage procedure, first using orthognathic surgery (Le Fort I osteotomy) to correct occlusal cant, followed by orthomorphic surgery (extended lateral sliding genioplasty) 6 months later to correct the facial asymmetry and underdevelopment of the mandible. The combination of orthognathic and orthomorphic surgery successfully achieved functional and aesthetic goals by correcting the jaw deviation and restoring facial symmetry.
The document summarizes discussions from an early treatment symposium regarding the treatment of skeletal open bite malocclusions. It addresses questions about defining early treatment, the differences between dental and skeletal open bites, benefits of early treatment for hyperdivergent open bites, and appropriate treatment approaches. The optimal treatment is said to be beginning between ages 7-8 and includes rapid maxillary expansion, headgear, and light muscle exercises to control vertical growth and encourage counterclockwise mandibular rotation. Early intervention is advocated to modify growth and prevent needing future surgery.
Gingival recession—can orthodontics be a cure? evidence from a case presentationEdwardHAngle
A 35-year-old woman presented with severe gingival recession and a unilateral Class II malocclusion. Her treatment plan involved orthodontic correction of the malocclusion using brackets that torqued roots more onto the bone. It also involved changing her dental hygiene methods to use an oscillating toothbrush gently. After 28 months of orthodontic treatment, her malocclusion was corrected and her gingival recession improved without needing grafting. Three months later, her teeth had settled well into their new positions.
Effects of rapid palatal expansion on the sagittal and vertical dimensions of...EdwardHAngle
The purpose of this study was to use cone-beam computed tomography imaging to examine the skeletal and dental changes in the sagittal and vertical dimensions after rapid palatal expansion.
The document summarizes a journal club presentation on a 3-year study evaluating the clinical performance of short expandable dental implants in highly atrophic alveolar bone. The study found a 94.7% implant success rate in the mandible and 83.6% in the maxilla over a mean follow-up of 42.6 months, with median 3-year crestal bone changes demonstrating maintenance of peri-implant alveolar bone. The conclusion was that the short expandable implant system provided reliable oral rehabilitation, especially for elderly patients with difficult implantation conditions.
This document provides an overview of a book titled "Evidence-Based Decision Making: A Translational Guide for Dental Professionals". The book teaches dental professionals the essential skills of evidence-based decision making, including how to form clinical questions based on a patient case, search efficiently for relevant evidence, critically appraise evidence, apply evidence to patient care, and evaluate their EBDM performance. Each chapter contains objectives, activities, and case examples to reinforce skills. The goal is for readers to complete the full EBDM process for different clinical question types.
Segmental Fractures of the Forearm- Outcome Analysis of Various Management St...iosrjce
IOSR Journal of Dental and Medical Sciences is one of the speciality Journal in Dental Science and Medical Science published by International Organization of Scientific Research (IOSR). The Journal publishes papers of the highest scientific merit and widest possible scope work in all areas related to medical and dental science. The Journal welcome review articles, leading medical and clinical research articles, technical notes, case reports and others.
Mandibular arch form the relationship between dental and basal anatomyEdwardHAngle
We investigated mandibular dental arch form at the levels of both the clinically relevant application points of the orthodontic bracket and the underlying anatomic structure of the apical base. The correlation of both forms was evaluated and examined to determine whether the basal arch could be used to derive a standardized clinical arch form.
1) The document argues against routinely mounting dental casts on articulators for orthodontic treatment, as there is no convincing evidence that it improves outcomes.
2) While articulators may help elucidate jaw relationships, using them routinely appears perfunctory given that factors like occlusion and condyle position are no longer considered primary causes of temporomandibular disorders.
3) The paradigm around temporomandibular disorders has shifted from a dental model to a biopsychosocial one, and orthodontics is now considered temporomandibular disorders neutral.
This study compared the maximum intercuspation (MI) and centric relation (CR) harmony between three groups of post-orthodontic patients. Group 1 and 3 received gnathologically-based treatment using models, splints and instrumentation to assess MI and CR alignment. Group 2 received standard edgewise treatment without gnathological assessment. The study found statistically significant vertical condylar distraction in MI versus CR positioning in the non-gnathological group compared to the gnathological groups, suggesting gnathological treatment may better achieve functional MI-CR harmony.
The document discusses the use of articulators in orthodontics. It is divided into three parts:
1) The first part explains that articulators are used as diagnostic tools to uncover occlusal problems, particularly those involving the vertical dimension, which are otherwise hidden.
2) The second part demonstrates the techniques needed to properly use the articulator system, such as taking bite registrations and transferring the terminal hinge axis position.
3) The third part illustrates how articulators can be used for diagnostic techniques after mounting the models, including measuring condylar positions and creating diagnostic setups.
- There is no good evidence that orthodontics causes or cures temporomandibular joint dysfunction. Extracting teeth for orthodontic reasons does not inevitably alter a patient's facial profile. Better quality research is still needed in many controversial areas of orthodontics.
The document discusses the surgery first approach (SFOA) for orthognathic surgery. It provides historical context for SFOA and compares it to the conventional approach. It outlines the challenges with conventional surgery, indications and contraindications for SFOA, and the key steps involved - including preoperative procedures like bonding timing, archwires, and splints as well as virtual surgical planning. The document emphasizes that SFOA aims to reduce treatment time compared to conventional approaches.
The document discusses the biomechanics of space closure during orthodontic treatment. It covers topics such as determinants of space closure including axial inclination and midline discrepancies. It also discusses fundamentals of anchorage control including extraoral forces, intermaxillary elastics, and tipping movements. Additionally, it describes strategies for differential space closure such as applying different moment-to-force ratios to anterior vs. posterior teeth. The center of resistance during anterior retraction is also examined.
This document summarizes a literature review on the crown-to-root ratio (CRR) as a factor in evaluating teeth for fixed or removable partial dentures. It discusses that CRR refers to the relationship between the visible crown portion of the tooth above bone compared to the root portion embedded in bone. An ideal CRR is considered 1:1.5 to 1:2. While CRR is one factor, other issues like bone support, mobility, and opposing occlusion must also be considered. The document reviews several studies but notes there is lack of consensus on CRR's influence and that prognosis depends on multiple clinical factors.
68.Dr. Afreen Kauser; Dr. Rahul VC Tiwari; Dr. Ankita Khandelwal; Dr. Heena Tiwari; Dr. Sourabh Ramesh Joshi; Dr. Fawaz Abdul Hamid Baig; Dr. Anil Managutti. "Preference Of Orthodontic Treatment Versus Orthognathic Surgery In Class Iii Malocclusion Cases: A Research Survey". European Journal of Molecular & Clinical Medicine, 8, 1, 2021, 1271-1276.
This document summarizes the historical perspectives and controversies surrounding the definition of centric relation (CR) in orthodontics. It discusses how the definition of CR has changed over time from referring to a retruded, posterior condyle position to a contemporary understanding of an anterior-superior position. The document also reviews past literature regarding the recording and validity of CR records as well as the relationship between condyle position and temporomandibular disorders. A key conclusion is that current scientific evidence does not support the benefit of using gnathologic CR records and articulators in orthodontic treatment as the positions of the temporomandibular joint condyles have not been shown to be predictive of temporomandibular
This document presents a thesis comparing proximal femoral nailing and hemiarthroplasty for treating trochanteric fractures in elderly patients. The study aims to compare the functional and clinical outcomes of the two procedures and assess their efficacy. It will include patients over 60 years old with trochanteric hip fractures who were previously ambulatory. Patients will be randomly assigned to receive either proximal femoral nailing or hemiarthroplasty surgery. Follow-ups will occur at regular intervals to evaluate outcomes clinically and radiologically. The study aims to determine which procedure results in better stability, activity levels, recovery time, and fewer post-operative complications for treating trochanteric fractures in elderly patients.
This study analyzed the position and angulation of 300 maxillary central incisors using cone beam imaging to provide data to help clinicians achieve good esthetic results for immediate dental implants. The thickness of buccal and palatal bone and apical bone height were measured. Incisors were classified according to their position (buccal, midline, palatal) and angulation (toward buccal, anterior to A point, parallel to alveolus). Most incisors were positioned buccally. Recommendations for implant placement based on tooth classification aim to maintain adequate buccal bone thickness and prevent complications.
Cbct is the imaging technique of choice for comprehensive orthodontic assesmentNielsen Pereira
CBCT is proposed as the imaging modality of choice for comprehensive orthodontic assessment and treatment planning for several reasons:
1) CBCT provides accurate 1:1 geometry which allows for precise measurements and assessments of structures in all three planes of space, unlike 2D imaging.
2) It allows for accurate localization of impacted or ectopic teeth and assessment of root resorption, important factors for developing an effective treatment plan.
3) Features like airway assessment, temporomandibular joint imaging, and periodontal evaluation can be reviewed from CBCT volumes with no additional radiation exposure.
This study evaluated external root resorption (ERR) in root-filled teeth (RFT) and vital pulp teeth (VPT) after orthodontic treatment. The study assessed 69 patients who underwent either non-extraction or extraction orthodontic treatment. Pre- and post-treatment panoramic radiographs were used to measure root and crown lengths and areas to determine the amount of ERR. The results found that ERR was significantly higher in VPT compared to RFT. Additionally, the amount of ERR increased with longer treatment duration. However, the modality of treatment (extraction vs. non-extraction) did not significantly affect the amount of ERR in RFT. The study concluded that RFT are more resistant to ERR
1. This study compared apical root resorption between patients treated with fixed orthodontic appliances versus clear aligners using CBCT scans. 30 patients were divided into 3 groups: fixed appliances, clear aligners, and clear aligners with low-level laser.
2. Root volumes were measured before and after treatment using Mimics software by segmenting the lower incisor roots from CBCT scans.
3. Preliminary results found that root resorption accompanied by aligners was less than fixed appliances, however the difference was not statistically significant. Use of low-level laser also did not reduce root resorption.
Immediate effects of rapid maxillary expansion with haas-type and hyrax-type ...Dr. Carlos Joel Sequeira.
This randomized clinical trial evaluated and compared the immediate effects of rapid maxillary expansion (RME) using Haas-type and hyrax-type expanders through cone-beam computed tomography (CBCT) scans. 33 subjects were randomly assigned to either the Haas or hyrax group. Both groups underwent RME with 4 quarter turns of initial activation followed by 2 quarter turns per day until 8mm of expansion was reached. CBCT scans were taken before and after expansion. Measurements showed that both appliances significantly increased maxillary transverse dimensions, with greater skeletal than dental expansion. The hyrax group demonstrated greater orthopedic effects and less tipping of maxillary molars compared to the Haas group, but the differences were less
Journal Club Presentation on Overlay Removable Partial DentureNeerajaMenon4
Overlay removable partial dentures (ORPDs), a subset of overdentures, are often referred to as an RPD that has part of their components covering the occlusal surface of the abutment teeth to restore them into a functional occlusion
This study compared the skeletal and dental transverse effects of surgically assisted rapid maxillary expansion (SARME) using Haas versus Hyrax expanders in 38 patients aged 18-39 years. Measurements of maxillary width, upper intermolar width, and molar inclination were made before, immediately after, and 4 months after SARME. Both groups showed significant increases in maxillary width and intermolar width immediately after SARME, with decreases at 4 months but remaining significantly wider than before. The amount of maxillary widening was about 70% of the intermolar width increase. Clinically, the transverse effects were similar between the Haas and Hyrax groups.
The aim of this retrospective study was to cephalometrically evaluate and compare the skeletal and dental effects of a transverse sagittal maxillary expander (TSME) and a Hyrax-type expander (RME) in children with maxillary hypoplasia. Fifty subjects were divided into two groups, one treated with a TSME and the other with a RME. Cephalometric measurements before and after treatment showed that the TSME group had a statistically significant increase in anterior positioning of the maxilla and maxillary incisors, while the RME group saw an increase in upper molar positioning and total anterior facial height. The TSME was found to be more effective at producing skeletal changes and correcting max
This document describes a technique for selectively intruding overerupted molars in adult patients using a combination of selective alveolar corticotomies and a modified full-coverage maxillary splint with nickel-titanium springs. Two case reports are presented where this approach successfully intruded overerupted maxillary molars within 2.5-4 months without side effects. The technique aims to take advantage of the regional acceleratory phenomenon caused by corticotomies to increase orthodontic treatment efficiency for adult patients who require molar intrusion.
This study compared changes in keratinized gingiva height after orthodontic treatment with and without alveolar corticotomy and bone grafting. Two groups of 35 orthodontic patients each were matched for various factors. Keratinized gingiva height increased significantly by 0.78 mm after treatment with corticotomy and bone grafting but decreased by 0.38 mm after conventional orthodontics. The study suggests that combining orthodontics with alveolar corticotomy and bone grafting can result in increased keratinized gingiva height, offering additional periodontal protection compared to conventional orthodontics alone.
This document summarizes the technique of adult rapid maxillary expansion with corticotomy. It begins by reviewing literature showing rapid maxillary expansion is effective for growing children but often fails in adults due to increased facial skeleton rigidity. The described technique uses corticotomy cuts to weaken the rigid adult facial skeleton and surgically open the midpalatal suture to allow rapid maxillary expansion. Specifically, it involves making lateral cuts along the maxillary sinus wall and zygomatic buttress and a midline cut through the sealed palatal suture to separate the maxilla from surrounding bones. This corticotomy is intended to reduce resistance and enable maxillary expansion in adults via the same orthodontic forces used successfully in children.
This finite element analysis compared the biomechanical effects of different corticotomy approaches on tooth movement during maxillary canine retraction. 24 corticotomy models were designed varying the position, distance from the canine, and width of the cuts. The results showed that a distal corticotomy close to the canine resulted in the greatest canine displacement and lowest strain in the periodontal ligament, suggesting it may be the best approach for facilitating canine retraction. As the distance between the corticotomy and canine increased, its biomechanical effects on tooth movement decreased. The width of the cut did not significantly influence the results.
Este estudio piloto comparó clínicamente la velocidad del movimiento ortodóncico y los cambios en los parámetros periodontales entre pacientes tratados con ortodoncia convencional y ortodoncia facilitada con corticotomía para el tratamiento de apiñamiento dental anterior. Diez pacientes participaron, 5 en cada grupo. Los resultados mostraron que los dientes sometidos a ortodoncia y corticotomía presentaron una mayor velocidad de movimiento durante los primeros 30 días en comparación con el grupo control. No hubo diferencias significativas
Corticotomía microcirugía ortodóntica en paciente con periodonto reducido...Dr. Carlos Joel Sequeira.
El tratamiento de una paciente con periodontitis, maloclusión y periodonto reducido requirió varias técnicas quirúrgicas y ortodónticas. Se realizó una corticotomía con bisturí piezoeléctrico en el maxilar superior para acelerar el tratamiento ortodóntico. Adicionalmente, se llevó a cabo cirugía periapical para eliminar una lesión en el diente 12, regeneración tisular guiada en el diente 23 y relleno óseo de defectos. Seis semanas
Este documento presenta una perspectiva histórica de la evolución de la técnica quirúrgica de corticotomía desde su origen en 1892 hasta su última modificación en 2012. Detalla las diferentes técnicas propuestas a través del tiempo, incluyendo la técnica de bloques óseos de Köle en 1959, la ortodoncia rápida de Chung en 1975-1978, la técnica alveolar selectiva de Generson en 1978 y la ortodoncia osteogénica acelerada y periodontalmente acelerada de Wilcko en 2001,
Comparison of corticotomy facilitated vs standard tooth-movement techniques i...Dr. Carlos Joel Sequeira.
1) The study compared the effects of a corticotomy-facilitated (CF) technique to a standard tooth movement (S) technique in accelerating orthodontic tooth movement in dogs.
2) The maxillary first premolars were distalized using miniscrews and nickel-titanium coil springs on both the right (CF) and left (S) sides of the maxilla.
3) Tooth movement was significantly faster with the CF technique, which involved corticotomy cuts and perforations, doubling the rate of tooth movement compared to the standard technique.
This study evaluated age and gender differences in condylar growth and glenoid fossa displacement in French Canadian children and adolescents over 4-year periods. The results showed that:
1) The mandibular condyle grew superiorly between 9.0-10.7 mm and posteriorly between 0.8-1.3 mm over 4 years, with boys exhibiting greater superior growth during adolescence compared to childhood.
2) The glenoid fossa was displaced posteriorly between 1.8-2.1 mm and inferiorly between 1.0-1.8 mm over 4 years, with greater posterior and inferior displacement during adolescence compared to childhood.
3) Both condyl
This document summarizes the shift in the conceptualization and treatment of temporomandibular disorders (TMD) from a dentally-based model to a medically-based model over the past 40 years. It describes early research at the University of Illinois that conducted controlled clinical trials testing single-modality treatments for TMD, including medications, physical therapies, oral appliances, TENS, and psychological therapies. The studies found high placebo response rates of 35-60% across treatments. Placebo treatments like sham prescriptions, placebo splints, and mock occlusal adjustments were also effective for many patients, demonstrating the strong psychological factors involved in TMD. The results challenged traditional dental concepts and treatment of TMD,
This study assessed the reproducibility of measurements made using the Condylar Position Indicator (CPI) by evaluating intra-operator and inter-operator variability. Three operators took CPI recordings of standardized acrylic models and stone models that were poured from impressions of the acrylic models. Results showed very low variability between operators in readings of the same recording strips. Intra-operator variability was also low for recordings made of both the acrylic and stone models. Variability was slightly higher for the stone models compared to the acrylic models, and transverse readings showed the least amount of variability compared to vertical and anterior-posterior readings. The findings suggest the CPI provides accurate and reproducible measurements with minimal technique-induced error.
The reproducibility of the Roth power centric bite registration technique for determining centric relation was investigated. Three operators performed the technique on 18 subjects to measure interoperator variability, with each operator performing it 3 times to measure intraoperator variability. Measurements of condylar position were recorded using a condylar position indicator and compared statistically. The results showed no statistically significant differences within or between operators, indicating the Roth power centric technique reproduces centric relation with a high degree of accuracy and reliability.
mandibular condyle position comparison of articulator mountings and magnetic ...Dr. Carlos Joel Sequeira.
This study evaluated the reliability of jaw positions using articulator mountings and MRI in 28 symptom-free subjects. The results showed:
1) Articulator analysis found CO and CR positions were statistically replicable between trials. CO was distinct from RE and CR, but RE and CR could not be distinguished.
2) MRI found half the subjects had condylar concentricity consistent across positions, while 13% had anteriorly displaced disks not influenced by condyle position.
3) Treating to CR was not supported as a way to improve disk-condyle relationships, as MRI did not find CR to be a unique or reproducible position distinct from other positions.
Integrating Ayurveda into Parkinson’s Management: A Holistic ApproachAyurveda ForAll
Explore the benefits of combining Ayurveda with conventional Parkinson's treatments. Learn how a holistic approach can manage symptoms, enhance well-being, and balance body energies. Discover the steps to safely integrate Ayurvedic practices into your Parkinson’s care plan, including expert guidance on diet, herbal remedies, and lifestyle modifications.
Basavarajeeyam is an important text for ayurvedic physician belonging to andhra pradehs. It is a popular compendium in various parts of our country as well as in andhra pradesh. The content of the text was presented in sanskrit and telugu language (Bilingual). One of the most famous book in ayurvedic pharmaceutics and therapeutics. This book contains 25 chapters called as prakaranas. Many rasaoushadis were explained, pioneer of dhatu druti, nadi pareeksha, mutra pareeksha etc. Belongs to the period of 15-16 century. New diseases like upadamsha, phiranga rogas are explained.
Histololgy of Female Reproductive System.pptxAyeshaZaid1
Dive into an in-depth exploration of the histological structure of female reproductive system with this comprehensive lecture. Presented by Dr. Ayesha Irfan, Assistant Professor of Anatomy, this presentation covers the Gross anatomy and functional histology of the female reproductive organs. Ideal for students, educators, and anyone interested in medical science, this lecture provides clear explanations, detailed diagrams, and valuable insights into female reproductive system. Enhance your knowledge and understanding of this essential aspect of human biology.
Muktapishti is a traditional Ayurvedic preparation made from Shoditha Mukta (Purified Pearl), is believed to help regulate thyroid function and reduce symptoms of hyperthyroidism due to its cooling and balancing properties. Clinical evidence on its efficacy remains limited, necessitating further research to validate its therapeutic benefits.
Does Over-Masturbation Contribute to Chronic Prostatitis.pptxwalterHu5
In some case, your chronic prostatitis may be related to over-masturbation. Generally, natural medicine Diuretic and Anti-inflammatory Pill can help mee get a cure.
8 Surprising Reasons To Meditate 40 Minutes A Day That Can Change Your Life.pptxHolistified Wellness
We’re talking about Vedic Meditation, a form of meditation that has been around for at least 5,000 years. Back then, the people who lived in the Indus Valley, now known as India and Pakistan, practised meditation as a fundamental part of daily life. This knowledge that has given us yoga and Ayurveda, was known as Veda, hence the name Vedic. And though there are some written records, the practice has been passed down verbally from generation to generation.
ABDOMINAL TRAUMA in pediatrics part one.drhasanrajab
Abdominal trauma in pediatrics refers to injuries or damage to the abdominal organs in children. It can occur due to various causes such as falls, motor vehicle accidents, sports-related injuries, and physical abuse. Children are more vulnerable to abdominal trauma due to their unique anatomical and physiological characteristics. Signs and symptoms include abdominal pain, tenderness, distension, vomiting, and signs of shock. Diagnosis involves physical examination, imaging studies, and laboratory tests. Management depends on the severity and may involve conservative treatment or surgical intervention. Prevention is crucial in reducing the incidence of abdominal trauma in children.
Osteoporosis - Definition , Evaluation and Management .pdfJim Jacob Roy
Osteoporosis is an increasing cause of morbidity among the elderly.
In this document , a brief outline of osteoporosis is given , including the risk factors of osteoporosis fractures , the indications for testing bone mineral density and the management of osteoporosis
2. guidance when the mandible is protruded. Furthermore,
Chiappone6
and Roth1
recommended the use of panto-
graph tracings with articulators. Factors such as inter-
condylar distance, angle of the eminentia, the amount
and quality of the Bennett side shift, and the direction
of the rotating condyle in a vertical plane are presumed
to play roles in attaining their treatment objectives,1,6
even though these factors seem to have limited, if any,
relationships and applicability with the articulator.
Also, McLaughlin43
adds the following list of addi-
tional benefits of mounting: discern vertical MI-CR
discrepancies such as “molar fulcruming,” show cants
to the occlusal plane, uncover functional side shifts of
the mandible, perhaps show premature anterior contacts
with a lack of posterior contacts, and might show
unilateral prematurities with lack of contact on the
opposing side.
In addition to the foregoing, the Roth view also
maintains that patients need to be deprogrammed from
their preexisting occlusions before obtaining CR
records even when they do not have TMD.2-4,9
He
believed this can be achieved only with a repositioning
splint for at least 3 months.9
Roth1-5
conjectured that
the stability of the orthodontic treatment result is
jeopardized when CR is recorded in any other way.
Wood et al7
suggested that it might be impractical to
place every patient in a CR splint and instead advocated
using Roth’s 2-piece power CR registration before
treatment because it “seats the condyles better than
other techniques that do not use a hard anterior stop.”
Conversely, nongnathologic orthodontists tend to
use hand-held models and noninstrument-oriented CR
techniques. Treatment goals are more general and
include the attainment of the best occlusal relationship
within the framework of favorable dentofacial esthet-
ics, function, and stability. Nongnathologic orthodon-
tists assert that there is a tolerance for MI-CR slides up
to perhaps 2-4 mm in the horizontal plane with little or
no attention to the relevance of the vertical and trans-
verse dimensions.25,26,29,33,36
In support of the gnathologic view and the use of
articulators, there are several anecdotal reports of ortho-
dontic patients’ treatments that have allegedly gone
wrong because they were not initially diagnosed via an
articulator mounting. An example of this is the case
report by Derakhshan and Sadowsky.8
Their article is
an afterthought reflection about the orthodontic treat-
ment of a 41-year-old woman who they initially be-
lieved had a very slight Angle Class II Division 1
malocclusion. After several months in orthodontic
treatment, they observed a significant increase in over-
jet, anterior bite opening, increased anterior face height,
and excessive lip strain. The patient eventually had to
have adjunctive orthognathic surgery. The authors la-
mented that they had not performed a pretreatment
mounting, which might have aided in the diagnosis of
the hidden dental/skeletal problem.
Logically, one would think that the change in
definition and the movement of CR from a posterior-
superior to an anterior-superior position would have
eliminated or reduced the magnitude of centric slides
and possibly the importance of mounting.29
To a
degree, this has proven to be true. Furthermore, only
minor differences for MI-CR discrepancies have been
found between gnathologically treated and nongnatho-
logically treated orthodontic cases as determined via
articulator mountings and only for the vertical (not
horizontal or transverse) dimension. The MI-CR differ-
ence is only about 1 mm (discussed further in next
paragraph).38
Nonetheless, gnathologists argue that
consideration and measurements of minor MI-CR
slides (discrepancies) are still valid and can be diag-
nosed only by articulator mountings.1-21,40
Using a Roth power centric bite registration and
articulator-mounted models, Utt et al13
found centric
occlusion (CO) condyles (via student articulating mod-
ule articulator with mandibular position indicator) lo-
cated on average 0.53 mm posterior and 0.72 mm
inferior to the anterior-superior CR. There was, how-
ever, much individual variation, with 39% of the CO
condyles positioned anteroinferiorly from anterior-su-
perior CR.13
Recent studies comparing gnathological
(Panadent articulator with condylar-position indicator and
Roth principles) with nongnathologic finished ortho-
dontic cases have generally found articulator-recorded
MI-CR differences of 1 mm greater in the vertical plane
in nongnathologically treated patients (1.41 mm for the
nongnathologically treated v 0.41 mm for the gnatho-
logically treated; difference of 1 mm).18
Based on the
results of Utt et al13
and Crawford,11
orthodontic
gnathologists claim that anterior-superior CR slides
average 0.6 to 0.7 mm horizontally, 0.7 to 0.8 mm
vertically, and 0.27 to 0.3 mm transversely.40
Klar et
al41
found a small but statistically significant (perhaps
not clinically significant) change in the before and after
MI-CR recordings of 200 consecutively treated orthodon-
tic patients for whom gnathologic principles were used:
horizontally, 0.81 to 0.53 mm (difference of 0.28 mm);
vertically, 0.99 to 0.60 mm (difference of 0.39 mm);
transversely, 0.44 to 0.25 mm (difference of 0.20 mm).
A subissue of the mounting debate involves
whether some or all orthodontic cases need to be
mounted. Some gnathologists believe that only certain
ones need mounting: patients requiring orthognathic
surgery, TMD patients, most adult patients, those with
many missing permanent teeth, those with functional
American Journal of Orthodontics and Dentofacial Orthopedics
February 2006
300 Rinchuse and Kandasamy
3. crossbites and midline discrepancies, and those with
deviations on opening/closing. The most logical re-
sponse to this subissue was addressed by Roth advocate
Cordray,9
who believes that all cases need to be
mounted. He based his thinking on the notion that no
practitioner can determine beforehand which patients
are really, or will turn out to be, the troubling ones;
therefore all need mounting.
THE POLYCENTRIC HINGE JOINT ARTICULATOR
Advocates of the polycentric hinge articulator
(POLY) believe this instrument resolves some limita-
tions of the hinge-axis based conventional arcon-type
articulators. Alpern and Alpern44
stated:
All of the existing jaw replicators or articulators
(except the POLY) currently used today are based on
knowledge and technology more than a century old.
They are primitive replications of the human TMJ.
. . . Being single centric hinge joint mechanisms,
they could not possibly reproduce all of the human
jaw movements required to build dental appliances.
POLY advocate Leever45
claimed:
The polycentric hinge joint occlusal system . . . pro-
vides the freedom of opportunity to . . . reproduce
individualized jaw movement and associated tooth
relationships. The condyle/fossa relationships . . . are
juxtaposed to reproduce the bilateral, asymmetric con-
dyle/fossa relationships of the human skull complex.
The use of the POLY involves taking a submento-
vertex radiograph, measuring the angle and distance of
each condyle, and programming this information into a
fully adjustable polycentric hinge joint articulator.
Nuelle46
proposed that, if 1 condyle imaged from
submentovertex is cocked and at a higher angle than the
opposite condyle, the condyle with the higher angle
will move faster than the opposite condyle with a lower
intercondylar angle. Nuelle and Alpern47
asserted that
this type of condyle variation and others can be
incorporated into the POLY.
UNDERSTANDING THE ISSUES RELATED TO
MOUNTING
For the pro-mount viewpoint to have credibility and
merit, its arguments must be both logical and evidence-
based. The “mounters” must provide support for the
following:
In light of the modern view of occlusion and
condylar position and their minimal impact on temporo-
mandibular disease, gnathologically oriented ortho-
dontists must provide evidence for the need to analyze
and evaluate orthodontic patients’ occlusions and con-
dylar positions in a microscopic v macroscopic manner.
They must provide evidence that the use of mounted
models affects in some appreciable way how orthodon-
tic patients are diagnosed and treated and that all of this
has something to do with their stomatognathic health.
Next, there must be proof for the basic tenets of the
gnathology/mounting philosophy, such as a true (phys-
iologic) verifiable terminal hinge axis and CR position.
In this regard, there must be a consensus as to what
constitutes CR (definition).
They must also substantiate that the current static
bite registrations used to program the articulator are
valid—ie, have something to do with jaw function and
temporomandibular joint (TMJ) health—and locate
condyles in a seated anterior-superior CR position. If
so, they must provide evidence that the articulator and
mounting protocol can accurately receive and duplicate
the recorded jaw positions and movements.
THE VIEW AGAINST MOUNTING
The compelling evidence of today, and the historic,
evidence-based data of some 30 years, makes one
question some of the past gnathological thinking and
ideas about the rationale for mounting.25,27,28,30,31,48
Denotatively, the findings in the 1960s that centric
slides caused TMD were based on faulty information
from descriptive studies that lacked control or compar-
ison groups. When comparison groups that used TMD-
asymptomatic subjects were added to the studies’
designs, the same centric slides were also observed in
the TMD-asymptomatic group. Hence, many studies of
the 1960s had high diagnostic sensitivity but poor
diagnostic specificity, leading to false-positive TMD
diagnoses.49
Furthermore, intraoral telemetry studies of
the 1960s (in which miniature radio implants were
placed in fixed prosthesis of subjects and radio frequen-
cies monitored outside the mouth) found that, even
though entire dentitions were reconstructed into
retruded, posterior-superior CR, subjects continued to
use and function in CO.50-53
Parenthetically, Mc-
Namara et al,26
in a recent summary article, found TMJ
arthropathies associated with centric slides greater than
4 mm. However, they contended that the slides were
probably the result of the TMD rather than the cause.26
There is the suggestion that the routine mounting of
orthodontic patients’ casts allows for a detailed analysis
of the occlusion.1-21,40-42
However, the roles of occlu-
sion and condyle position have been demonstrated to be
less important than once thought.23,25-29,48,49,54-66
In
addition, it has been demonstrated that there is poor
diagnostic sensitivity and specificity of occlusal factors
related to TMD.25,26,48,49,54-57
Furthermore, the centric-
ity of the condyles in the glenoid fossa involves a
range, and eccentricity does not necessarily indicate
American Journal of Orthodontics and Dentofacial Orthopedics
Volume 129, Number 2
Rinchuse and Kandasamy 301
4. TMD.49,56-59,61-65
Therefore, the analysis of articulated
casts will not be diagnostic of TMD per se.49
And,
if TMD is a collection of disorders with many sub-
classes23,56,57
with a multifactorial etiology (it previ-
ously was viewed as a single disorder—TMJ pain-
dysfunction syndrome or myofascial pain dysfunction,
with a single etiology, ie, occlusion or stress) and
occlusion is only a very small piece of the puzzle, then
the need to record, measure, and focus on the details of
occlusion and condyle position does not make sense.
The rationale for the need and use of a sophisticated
instrument (and the articulator is not one) to analyze
and evaluate occlusion and condyle position would be
illogical.
Another antithetical point to the mounting position
is the evidence-based data that supports the view that
orthodontics does not cause TMD.22-29,34-36,61-65
The
gnathologists of the 1970s taught that, because ortho-
dontists ignore functional occlusion (including centric
slides) and treat only to a static, morphologic, ideal
occlusion, their patients would develop occlusal dishar-
monies or displaced condyles that would predispose to
TMD. Parenthetically, orthodontic gnathologists of that
era recommended treating patients to a fallacious
retruded CR position (posterior-superior). The ortho-
dontic gnathologist now accepts the current anterior-
superior definition of CR. If the gnathologically ori-
ented orthodontists’ views were correct, orthodontic
patients treated with hand-held models should have
different types of functional occlusion and condyle
positions and consequently increased TMD than similar
untreated comparison groups. However, the evidence-
based literature supports the contrary position: func-
tional occlusions, condyle positions, and level of TMD
are no different in orthodontically treated than un-
treated comparison groups.22-29,34-36,61-66
Johnston29
offered a critique of orthodontic gna-
thology and the false notions related to retruded CR:
I know of no convincing evidence that condyles of
the patients with intact dentitions “should” be placed
in centric relation or that once having been placed
there, the resulting improvement on nature will be
stable. . . . Instead of demanding a rational theoret-
ical basis and convincing proof, we took ‘how to’
courses and bought big articulators. . . . [I]t could be
argued that the progressive modification in the defi-
nition of centric relation has done more to eliminate
centric slides than 20 years of grudging acquiescence
to the precepts of gnathology.
One of the more-often cited reasons for mounting is
to identify the patient who has a dual bite. It is argued
that this might preclude an accurate diagnosis of the
patient’s skeletal pattern and dental classification.9
However, once a dual bite has been identified clinically,
how does the mounting of casts allow for a more
accurate treatment plan? Isn’t obtaining the correct bite
the critical factor?
CR RECORDS: RELIABILITY?
Orthodontic gnathologists argue that the assessment
of 3-dimensional condylar position is not possible with
2-dimensional radiography. They contend that the
power centric bite registration with articulator mount-
ings is the best and only way to evaluate CR.9,11-21
This
notion of the gnathologists appears to ignore the known
superiority of TMJ magnetic resonance imaging
(MRI).30
Admittedly, gnathological records such as the
Roth power centric bite registration and the articulator
mounting instrumentation appear to be reliable (repeat-
ability and consistency of the records/techniques) at
least under controlled laboratory conditions.16,42
How-
ever, in 1 study, standard deviations were found for
gnathologic MI-CR records as high as 0.16 mm in the
horizontal and vertical planes and 0.13 mm in the
transverse plane, and “play” error was calculated as
0.01 to 0.05 mm.16
Furthermore, the extent of error in
the gnathologic approach has not been fully investi-
gated. Orthodontic gnathologists Lavine et al16
stated,
after conducting their study dealing with the reliability
of the articulator condylar-position indicator (Pana-
dent): “The exact sources of error, material or human,
were not assessed; however, a trend of increased
variability was noted as the complexity and number of
the steps and materials increased.” Also, there might be
potential errors from using average values in the
articulator setup and an instrument that has the maxil-
lary component moving rather than the mandible as
does the human jaw.67-70
And, because there are only
very small differences between gnathologic and nong-
nathologic MI-CR records, even a small error calcu-
lated against any of the study findings would further
reduce the significance of gnathologic data.
CR RECORDS: VALIDITY?
CR recordings assume that it is possible to precisely
locate particular positions of the condyles. For exam-
ple, a 2-piece bite registration technique by Roth called
the power centric bite registration presumably seats the
condyles in an anterior-superior CR position, ie, “con-
dyles centered transversely and seated against the
articular disk at the posterior slope of the articular
eminences without dental interferences.”13
However,
Roth and other authors1-5,9,11,13,14,16,18-21
did not fur-
nish any evidence (MRI preferred) that subjects’ con-
dyles were actually in the positions that they described.
American Journal of Orthodontics and Dentofacial Orthopedics
February 2006
302 Rinchuse and Kandasamy
5. The validity of mounted dental casts very much de-
pends on the reliability and validity of the patient’s bite
registrations.30,31
Therefore, although the Roth bite
registration might be reliable, is it valid? Does the
technique actually “capture” condyles in anterior-supe-
rior CR? Does this have any relationship to human jaw
function and stomatognathic health?
Interestingly, recent MRI data have indicated that
condyles are not located where clinicians think they
will be as a result of certain bite registrations.30
Therefore, the validity of the Roth centric bite registra-
tion has been questioned.25,29,30
A study by Alexander
et al30
compared and evaluated the MRI condyle
positions of 28 TMD-asymptomatic men in regard to 3
different occlusal and jaw bite registrations. The CO
(maximum intercuspation) bite-generated condyles
were considered the ideal condyle position because
they naturally existed in the 28 TMD-asymptomatic
subjects. The CO condyles were compared with bite
registered retruded condyles (RE) and anterior-superior
(CR) condyles. Interestingly, the CO-generated con-
dyles were shown to be distinct and positioned inferior
and anterior to the retruded (RE) and CR condyles.
Furthermore, the CO-generated condyles were not co-
incident with CR (anterior-superior) condyles. And it
was not possible to discriminate between the positions
in retruded (RE) and CR condyles. Alexander et al30
concluded that the clinical concept of treating to CR as
a preventive measure to improve disk-to-condyle rela-
tionships was unsupported.
Furthermore, Roth propagated the notion that the
power centric bite registration is physiologic and un-
manipulated based on his claim that it is “muscle
dictated.”1,9,13,17
However, the converse is probably
true; the power centric record is operator manipulated
and unphysiologic.25
Parenthetically, manipulated cen-
tric records (doctor manipulates subject’s mandible)
have been demonstrated to be more reliable than
unmanipulated centric records, but they are less phys-
iologic.25
Nuelle and Alpern47
reflected on the absur-
dity of gnathologic bite registrations:
Gnathologists . . . believe that the dentist can be
properly trained to manipulate, romance, dual wax
bite take, or other techniques which supposedly
permit the dentist or orthodontist to take control of all
the neuromuscular inputs to the patient and position
the mandible with the condyles positioned up and
forward against the eminence. . . . [N]o dentist or
orthodontist is knowledgeable enough to know the
proper three-dimensional position for two asymmetri-
cally angulated condyles, irregularly and individually
suspended in a polycentric hinged joint . . . Doctor se-
lected TMJ positioning at the dental chair is a blind
procedure.
An additional point somewhat related to bite regis-
tration is that the occlusal records used in mounting are
static and not dynamic. Patients or subjects are not
asked to chew food, swallow, or exercise any parafunc-
tion movement. Perhaps the way a patient or subject
uses his or her occlusion is far more important than the
occlusal morphology. Furthermore, the chewing-pat-
tern shape varies from subject to subject. Some people
possess a more vertical chewing pattern, and others
have a more horizontal pattern; this appears to be
independent of the occlusal scheme.25
A more erudite
explanation is that the chewing-pattern shape is sex-
specific, and there are more than half a dozen different
chewing patterns directly related to craniofacial mor-
phology.60
How then does the orthodontic gnathologist
justify articulator mountings that come from static and
not dynamic occlusal registrations? Even if the patient
was asked to perform any of these movements, how is
this incorporated into the articulator mounting?
Next, in the gnathologic approach, bite registrations
and mounted casts are taken just short of tooth contact.
Cordray9
addresses the reasoning for this:
The mandibular cast must be mounted at a point on
the seated condylar axis before first tooth contact
occurs, using an interocclusal record to relate it to the
maxillary cast. This is necessary to prevent a centric
prematurity from deflecting the mandible upon clo-
sure, which in turn allows for diagnosis of the
problems.
Although the rationale for taking the bite registra-
tion and mounting short of occlusal contact is clear, is
it valid? The fact remains that the articulator (vertical
stop pin) must eventually be released so that the teeth
(or perhaps a single tooth) finally drop into contact
(occlusion). Does gravity ultimately determine the final
seating of the casts after all the trouble and effort of
mounting?
Curiously, the mounting advocates believe that the
mounting process and instrumentation are accurate
(valid) without verification. Cordray9
wrote, “When
these records are properly transferred to an articulator,
the relationships between the teeth and jaws can be
studied accurately.” However, the validity of the artic-
ulator and the methods used in mounting are dubious.
Alpern and Alpern44
stated, “Nearly all existing single
centric hinge joint articulators produce only two paths
of straight-line movement, whereas the patient has an
infinite number of unique multiple paths of movement
as teeth function.”
Finally, the anatomy of the articulator does not
American Journal of Orthodontics and Dentofacial Orthopedics
Volume 129, Number 2
Rinchuse and Kandasamy 303
6. mimic human form. The articulator condyle does not
look like an actual condyle. The articulator does not
account for differences in the size, shape, and orienta-
tion of condyles between the right and left sides or for
right-and-left asymmetries in ramus height. Articula-
tors do not legitimately account for differences in the
angle of the slope of the articular eminence. And the
articulator does not have TMJ discs and capsules,
ligaments, muscles, blood vessels, or nerves of the
human stomatognathic system.
ABILITY OF ARTICULATORS TO SIMULATE JAW
MOVEMENTS?
The most important argument against mounting is
that the articulator is based on the faulty 1952 concept
of Posselt.71
Posselt assumed that, in the initial phase of
jaw opening, the condyles only rotate and do not
translate—ie, terminal hinge axis. There is, however, an
instantaneous center of rotation (translation) supported
by Luce in 1889 and later by Bennett in 1908, cited in
Lindauer et al.31
That is, the mandible initially under-
goes both rotation and translation around an axis, which
continues as the jaw opens. Support for this notion
comes from the study of Lindauer et al,31
who studied
condylar movements and centers of rotation during jaw
opening in 8 normal (no TMD) subjects with the
Dolphin Sonic Digitizing System. They found that all
subjects demonstrated both rotation and translation
during initial jaw opening, and none had a center of
rotation at the condylar head. Their findings supported
the theory of a constantly moving, instantaneous center
of jaw rotation (translation) during opening that is
different in every person. The arcon hinge-type articu-
lator does not incorporate initial translatory movement
of the condyles during opening. The authors con-
cluded that the use of articulators to simulate “jaw
movements to identify occlusal interferences cannot
be expected to replicate the patient’s mandibular
movements precisely.”31
They further stated, “The
uncertainty of predicting mandibular rotation for a
given patient should be considered when planning
surgical treatment and fabrication of orthodontic appli-
ances.”31
Nuelle and Alpern47
believed that the polycentric
hinge articulator “can reproduce the patient’s individual
chewing stroke” and avoid the problems of the arcon
hinge-type articulators. Arguably, they believe that the
POLY can incorporate initial translation not possible
with hinge axis articulators. Parenthetically, Nuelle and
Alpern47
recommended using a full-arch splint “for a
period of time to eliminate all muscle splinting and/or
joint inflammation,” and then the “patient’s joints will
consistently demonstrate where their natural centric is
located.”
IS THERE AN OUTCOME BENEFIT?
An important question that can be asked of the
orthodontic gnathologist is: how does the mounting of
dental casts affect orthodontic diagnosis and treatment
planning and lead to improvements in orthodontic
treatment outcomes—ie, occlusion and TMJ health?
Just because an additional step is incorporated into the
diagnostic protocol does not mean it is efficacious.
Ellis and Benson32
recently assessed whether articula-
tor-mounted casts in CR compared with intercuspal
position (CO) hand-held casts made a difference in
orthodontic treatment planning. They concluded that
mounting the study models of 20 orthodontic patients
did not meaningfully affect the treatment planning
decisions of 10 orthodontists in the United Kingdom
compared with hand-articulated casts.32
Last, mounting patient casts on an articulator fur-
nish no biologic information about apparent health or
disease. Diseases of the TMJ such as disc displacement
and osteoarthrosis are diagnosed via TMJ imaging
(MRI) and clinical examination, not by using articula-
tors.
PRACTICAL CONSIDERATIONS
Interestingly, many who support the mounting
viewpoint use gnathologic positioners to finish their
treatments. However, the objections for the use of
articulators we offer are multiplied when using a
gnathologic positioner. Alpern and Alpern44
discussed
the further problem of opening the pin on hinge-type
articulators when constructing splints or performing
clinical laboratory procedures for dental restorations.
They stated:
Existing knowledge clearly states that you cannot
open the front pin or post on any single centric hinge
joint articulators. If you do, the resultant dental
restoration will not fit, with the posterior teeth touch-
ing first and an anterior open bite resulting.
It seems ridiculous to go through all the effort to
detail an orthodontic case over 2 years and then finish
with an absolutely inaccurate appliance such as a
gnathologic positioner.
Furthermore, how does the use of an articulator
factor in the settling of the occlusion after orthodontic
appliances are removed? Surely, when the gnathologist
performs a pretreatment diagnostic mounting, he or she
assumes that this process will have an ultimate impact
on establishing the final occlusion (assuming a final
occlusion is ever established). Would it not be defeat-
American Journal of Orthodontics and Dentofacial Orthopedics
February 2006
304 Rinchuse and Kandasamy
7. ing to learn that, after all the effort involved with
mounting and the attention paid to the details of
occlusion and condyle position, the final occlusion is
often arbitrarily determined by nature? The patient’s
own adaptation (settling) overrides the immediate pos-
torthodontic occlusion.
Several additional points can be made that are
critical to the debate on mounting in orthodontics. First,
there is evidence that the glenoid fossa/condyle com-
plex changes position in children due to growth.72
If
this is true, the gnathologist would have to periodically
remount and reevaluate growing children’s cases. How
many gnathologists consider this?
Additionally, in modern health care when cost
containment is a critical element, a question can be
asked: what is the added cost to mount versus not to
mount? The gnathologists ardently argue that there is
no more added cost to mount than that of obtaining
hand-held models. However, no matter how passion-
ately they argue, the fact remains that there are greater
costs if one considers factors such as staff training and
use, additional laboratory time, and the storage of
articulator records. Furthermore, if e-models take hold
and the orthodontic office of the future becomes more
digital and paperless, how do the articulator and its
records factor into this new paradigm?
RECENT STUDIES SUPPORTING MOUNTING
QUESTIONED
Several recent studies presumably support the
mounting viewpoint.7,8,11-18,40-42
Even though there is
no perfect study, the studies supporting mounting are
flawed and reflect more general problems about articu-
lators. Rinchuse25
reviewed 1 of these articles13
and
clearly pointed out many shortcomings beyond those of
typical published studies. Some of the general short-
comings of the articles are:
● The studies were descriptive rather than experimental
or observational and did not address cause and effect.
● No comparison group was used, or, when a compar-
ison group was present, the selection process was
biased.
● The findings had nothing to do with the health or
disease of subjects’ TMJs. The studies, for the most
part, did not relate millimeter differences in articu-
lator recordings to TMD or stomatognathic health. If
differences exist between articulated condyles of
subjects, so what?
● The basic premise was faulty in that the findings
generally demonstrated normal variability of condyle
position from subject to subject. Slight millimeter
and fraction of millimeter differences between sub-
jects in the studies might not be clinically significant.
● The use of average condylar readings and no report
of the exact error involved in the bite registrations
and mounting procedures are problematic.
● The studies did not validate the power centric bite
registration and demonstrated that this registration
actually seats human condyles in the predicted fossa
position of anterior-superior CR.
The study by Crawford11
was perplexing. Its pur-
pose was to determine whether there is a relationship
between occlusion-dictated Panadent articulator condy-
lar position axis and signs and symptoms of TMD. That
is, do subjects having mutually protected occlusions
with MI and CR relatively coincident have fewer signs
and symptoms of TMD than subjects without these
types of occlusion and condyle position?73
The findings
purport that a relationship exists between occlusion-
dictated condylar position and TMD symptomatology.
However, the study has many limitations, the most
apparent of which is the sample. Thirty subjects with a
gnathologic, ideal occlusions, in which CR was coin-
cident with CO (intercuspal position, MI), were com-
pared with 30 subjects randomly selected from the
general population. Curiously, the so-called “ideal sam-
ple” was selected from a population that had undergone
full-mouth reconstruction with gnathologic principles.
The author11
claims that he used a selected sample
“because the incidence of adult occlusion with CR coin-
cident with CO (ICP; MI) is very low in the general
population, making the acquisition of an adequate
sample of ideal occlusions by random selection imprac-
tical.” Crawford11
wrote:
This was a sample of convenience, and it was highly
selected. The contributing clinicians chose subjects
according to their own concept of ideal, and the
number selected was determined by the availability
and willingness of the subjects to participate.
If the author recognizes that CR coincident with CO
(ICP; MI) is so rare in nature, then by whose standard
is it considered the ideal for which patient treatment
should be directed toward? Perhaps the author unknow-
ingly acknowledged the shortcoming concerning the
validity of the study before the data were even col-
lected. There was also an age difference between the 2
samples. The average age for the restored, ideal sample
was 50.8 years; that of the comparison group was 38.4
years. Age is a factor in TMD26,30,54,55,57
(TMD in-
creases with age but decreases after age 50).73
There
are also other biases dealing with how the restored
“ideal” sample was selected. How much did the clini-
American Journal of Orthodontics and Dentofacial Orthopedics
Volume 129, Number 2
Rinchuse and Kandasamy 305
8. cians who furnished subjects for the study know about
the study’s premise? It seems illogical that they did not
know the TMD status of these subjects a priori. The
examiners used in the study were not blinded and knew
which patients had full-mouth reconstructions and
which did not.73
Furthermore, the number of subjects in
each of the 2 groups (30 subjects) was inadequate
because of the many uncontrolled confounding factors.
Several additional points: the untreated subjects were
not deprogrammed, the palpation recording was not
standardized, the Helkimo index was modified to make
the data “work,” the Helkimo index is not specific for
TMD, possibly only happy patients were recalled, the
anamnestic results are questionable because subjects’
abilities to recall information 10 years later are tenu-
ous,73
and an impossible finding of a superior position
of the condylar-postion indicator was excused as an
“artifact.”
DEPROGRAMMING SPLINTS
The use of deprogramming splints has become an
integral part of the gnathological view on the pro
position of mounting. The evidence for using depro-
grammers is equivocal, with no true physiologic
basis. Several essays have described techniques for
deprogramming or discussed the benefits of depro-
gramming before performing a centric bite registra-
tion.74-85
Several studies have shown a possible benefit
of deprogramming,86,87
although most have not.88-90
All studies used deprogrammers for relatively short
time periods.86-90
The study of Karl and Foley87
involved the place-
ment of a Lucia-type anterior deprogramming jig (an-
terior tooth contact without posterior tooth contact) in
40 subjects. Minor differences were noted in articulator
condyle position indicator centric recording before and
after using the deprogrammer for 6 hours. The most
prevalent type of centric slide resulted on average in a
posterior and inferior distraction of the articulator
condyles from MI-CR of 0.37 mm horizontally and
0.57 mm vertically. Conversely, Kulbersh et al18
found
no difference in MI-CR measurements between 34
postorthodontic subjects who wore gnathologic full-
coverage splints for 3 weeks (24 hours per day) and 14
postorthodontic subjects who did not wear splints.
CONCLUSIONS
Science and the practice of orthodontics are not
mutually exclusive, as the orthodontic gnathologists
seem to believe. One would think that a consideration
of the modern knowledge that occlusion and condyle
position have minimal or no influence on TMD would
have quieted the debate on the use of articulators in
orthodontics. Also, the evidence that orthodontics does
not cause TMD should have been detrimental to the
mounting argument. In addition, the credibility of the
orthodontic gnathologists should certainly have been
shattered by their claim of mounting cases to a past
incorrect retruded CR position that they do not accept
today.
Although there is no evidence-based systematic
review (evidence-based Model 3)38,39
about mounting,
enough evidence clearly argues against orthodontic
patient mounting. A critical review of the available
literature and a logical consideration of the notions
about mounting in orthodontics make the pro position
difficult.
● The articulator can never simulate human mandibu-
lar movement and is based on the faulty theory of the
terminal hinge-axis.
● There is no evidence that orthodontic treatment
results (outcomes) are better when articulators are
used in terms of improved patient TMD status and
stomatognathic health.
● No scientific evidence suggests that the use of
articulators will influence orthodontic diagnoses in
any meaningful way.
● Although the polycentric hinge articulator is possibly
better than the hinge axis arcon articulator, it is by no
means ideal.
● CR records have only been demonstrated to be
reliable under controlled laboratory conditions.
● The errors involved in taking the bite registrations
and the mounting procedures reduce the significance
of the gnathologic findings.
● Bite registrations used in the mounting process are
static records and do not encompass any meaningful
movement of the human mandible.
● The internal validity of the Roth power centric bite
registration has not been established. Roth did not
demonstrate where patients’ condyles are positioned
as a result of the power centric bite registration; he
assumed they are in an anterior-superior seated
position, but he gave no documentation.
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American Journal of Orthodontics and Dentofacial Orthopedics
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308 Rinchuse and Kandasamy