Assessment of condyle and glenoid fossa morphology using CBCT in South-East Asians

Recommendations for standard criteria for the positional and morphological evaluation of temporomandibular joint osseous structures using cone-beam CT: a systematic review

OBJECTIVE

This systematic review aimed to appraise the reliability and comprehensiveness of imaging methods in studies that used three-dimensional assessment of the temporomandibular joint (TMJ) in order to propose a standardized imaging method.

METHODS

Six databases/search engines were searched up until September 2022. The outcomes of interest included measurements of the mandibular condyle, glenoid fossa, joint spaces, or the entire TMJ. Two checklists were utilized: one to assess the risk of bias, with a maximum score of 37, and the other, a pre-designed checklist consisting of 22 items to evaluate the comprehensiveness of the methods used, with a maximum score of 33.

RESULTS

Out of the 2567 records retrieved, only 14 studies, which used cone bean computed tomography (CBCT), were deemed eligible and thus included in the qualitative analysis. Three studies were deemed of low risk of bias, while the remaining studies were rated as moderate to high risk of bias, primarily due to improper reporting of inter-observer agreement, varying reliability values, and a limited number of cases included in the reliability analysis. Regarding the comprehensiveness of the methods used, only four studies achieved relatively high scores. The deficiencies observed were related to the reporting of variables such as slice thickness and voxel size, absence of or improper reporting of intra- and inter-examiner reliability analyses, and failure to assess all osseous components of the TMJ.

CONCLUSION

CBCT-based methods used to assess the positions and morphology of TMJ bony structures appear to be imperfect and lacking in comprehensiveness. Hence, criteria for a standardized assessment method of these TMJ structures are proposed.

CLINICAL RELEVANCE STATEMENT

Accurately, comprehensively, and reliably assessing the osseous structures of the temporomandibular joint will provide valid and valuable diagnostic features of the normal temporomandibular joint, and help establish potential associations between these osseous features and temporomandibular disorders.

REGISTRATION

The protocol for this systematic review was registered at the International Prospective Register of Systematic Reviews (PROSPERO, No.: CRD42020199792).

KEY POINTS

•Although many methods have been introduced to assess the osseous structure of the temporomandibular joint, they yielded inconsistent findings. •None of the published studies comprehensively assessed the temporomandibular joint. •Recommendations for a comprehensive temporomandibular joint osseous assessment method were suggested for better validity and reliability of future research.

Investigation of the accuracy of dynamic condylar position: A model study

OBJECTIVES

To evaluate dynamic condylar positions by integrating mandibular movement recording data and cone-beam computed tomography (CBCT) and to investigate its accuracy via dynamic model experiments.

METHODS

A polyvinyl chloride skull model was utilized. A robot arm was used to operate the mandible to perform mouth opening, closing, protrusion, and lateral movements. A recording device, worn on the skull, was used to record the dynamic process and an optical position tracking (OPT) system was used to simultaneously trace the movements. A self-developed software module was used to evaluate the dynamic condylar position by integrating the dynamic tracing data and a virtual skull model derived from CBCT images. Errors were defined as differences between the dynamic coordinates of six landmarks around the condylar area derived from the software module (test) and OPT system (gold standard).

RESULTS

The condylar position errors were 0.76 ± 0.31, 0.55 ± 0.15, and 0.68 ± 0.23 mm for mouth opening, bilateral, and protrusion movements, respectively. Furthermore, the errors for small, moderate, and large mouth opening movements were 0.62 ± 0.19, 0.69 ± 0.29, and 0.94 ± 0.31 mm, respectively. The errors for all movements, except for large mouth opening, were significantly less than 1 mm (P < 0.05). The error was not different from 1 mm in the large mouth opening movement (P > 0.05).

CONCLUSIONS

Our developed method of achieving dynamic condylar position by integrating mandibular movement recording data and CBCT images is clinically reliable.

CLINICAL SIGNIFICANCE

This study proved the reliability of evaluating dynamic condylar position using a commercial dynamic recording instrument and CBCT images.

Three-dimensional measurements of symmetry for the mandibular ramus

BACKGROUND

The study examines a sample of patients presenting for viscerocranial computer tomography that does not display any apparent signs of asymmetry, assesses the three-dimensional congruency of the mandibular ramus, and focuses on differences in age and gender.

METHODS

This cross-sectional cohort study screened viscerocranial CT data of patients without deformation or developmental anomalies. Segmentations were obtained from the left and right sides and superimposed according to the best-fit alignment. Comparisons were made to evaluate three-dimensional congruency and compared between subgroups according to age and gender.

RESULTS

Two hundred and sixty-eight patients were screened, and one hundred patients met the inclusion criteria. There were no statistical differences between the left and right sides of the mandibular ramus. Also, there were no differences between the subgroups. The overall root mean square was 0.75 ± 0.15 mm, and the mean absolute distance from the mean was 0.54 ± 0.10 mm.

CONCLUSION

The mean difference was less than one millimetre, far below the two-millimetre distance described in the literature that defines relative symmetry. Our study population displays a high degree of three-dimensional congruency. Our findings help to understand that there is sufficient three-dimensional congruency of the mandibular ramus, thus contributing to facilitating CAD-CAM-based procedures based on symmetry for this specific anatomic structure.

Evaluation of morphological and morphometric characteristics of the temporomandibular joint in children with different skeletal models in the sagittal and vertical direction

OBJECTIVE

This study aims to evaluate differences in the morphological and morphometric features of hard tissue components of the temporomandibular joint (TMJ) in the cone beam computed tomography (CBCT) images of children with different skeletal models in the sagittal and vertical plane.

METHODS

Condyle dimensions, horizontal condylar angle, the distance of the condyle center to the midsagittal plane, condyle position, eminence height, eminence inclination, condyle, and fossa shape and symmetry were evaluated in CBCT images in 190 TMJs in 95 pediatric patients. Patients were classified as Class 1-2-3 in the sagittal direction, as hypodivergent, normodivergent, and hyperdivergent in the vertical direction. Children were divided into 10-13 and 14-17 age groups.

RESULTS

The left superior joint space in children with a different skeletal model in the sagittal plane was lower and found to be statistically significant in Class 3 children (p < 0.05). A statistically significant difference was found lower in the left articular eminence inclination and height in Class 3 children (p < 0.05). The most common oval fossa form was seen in Classes 2-3 children (p < 0.05). It was determined that the anterior joint space was lower in hyperdivergent children and the condyle was located more anteriorly. The mediolateral length of the condyle and the height of the articular eminence were positively correlated with age.

CONCLUSIONS

The results revealed that the difference in skeletal models seen in sagittal and vertical planes in children may cause morphological and morphometric changes in the hard tissue components of TMJ.

Quantification of temporomandibular joint space in patients with juvenile idiopathic arthritis assessed by cone beam computerized tomography

OBJECTIVE

To describe a method to calculate the total intra-articular volume (inter-osseous space) of the temporomandibular joint (TMJ) determined by cone-beam computed tomography (CBCT). This could be used as a marker of tissue proliferation and different degrees of soft tissue hyperplasia in juvenile idiopathic arthritis (JIA) patients.

MATERIALS AND METHODS

Axial single-slice CBCT images of cross-sections of the TMJs of 11 JIA patients and 11 controls were employed. From the top of the glenoid fossa, in the caudal direction, an average of 26 slices were defined in each joint (N = 44). The interosseous space was manually delimited from each slice by using dedicated software that includes a graphic interface. TMJ volumes were calculated by adding the areas measured in each slice. Two volumes were defined: Ve-i and Vi , where Ve-i is the inter-osseous space, volume defined by the borders of the fossa and Vi is the internal volume defined by the condyle. An intra-articular volume filling index (IF) was defined as Ve-i /Vi , which represents the filling of the space.

RESULTS

The measured space of the intra-articular volume, corresponding to the intra-articular soft tissue and synovial fluid, was more than twice as large in the JIA group as in the control group.

CONCLUSION

The presented method, based on CBCT, is feasible for assessing inter-osseus joint volume of the TMJ and delimits a threshold of intra-articular changes related to intra-articular soft tissue proliferation, based on differences in volumes. Intra-articular soft tissue is found to be enlarged in JIA patients.

Suggestion of a new standard in measuring the mandible via MRI and an overview of reference values in young women

PURPOSE

Adult idiopathic condylar resorption (AICR) mainly affects young women, but generally accepted diagnostic standards are lacking. Patients often need temporomandibular joint (TMJ) surgery, and often jaw anatomy is assessed by CT as well as MRI to observe both bone and soft tissue. This study aims to establish reference values for mandible dimensions in women from MRI only and correlate them to, e.g., laboratory parameters and lifestyle, to explore new putative parameters relevant in AICR. MRI-derived reference values could reduce preoperative effort by allowing physicians to rely on only the MRI without additional CT scan.

METHODS

We analyzed MRI data from a previous study (LIFE-Adult-Study, Leipzig, Germany) of 158 female participants aged 15-40 years (as AICR typically affects young women). The MR images were segmented, and standardized measuring of the mandibles was established. We correlated morphological features of the mandible with a large variety of other parameters documented in the LIFE-Adult study.

RESULTS

We established new reference values for mandible morphology in MRI, which are consistent with previous CT-based studies. Our results allow assessment of both mandible and soft tissue without radiation exposure. Correlations with BMI, lifestyle, or laboratory parameters could not be observed. Of note, correlation between SNB angle, a parameter often used for AICR assessment, and condylar volume, was also not observed, opening up the question if these parameters behave differently in AICR patients.

CONCLUSION

These efforts constitute a first step towards establishing MRI as a viable method for condylar resorption assessment.

Influence of botulinum toxin A in pain perception and condyle-fossa relationship after the management of temporomandibular dysfunction: a randomized controlled clinical trial

OBJECTIVES

To investigate the pain perception (PP) and condyle-fossa relationship (CFR) after botulinum toxin A (BoNTA) injection in the masseter muscles of painful muscular temporomandibular dysfunction (TMD) patients.

MATERIALS AND METHODS

Fourteen women (aged 29.7 ± 5.4 years) diagnosed with myogenic TMD were randomized in the BoNTA-treated group (TG) and control group (CG). TG masseter muscles (n = 7) were bilaterally injected with 30 U. The CG (n = 7) were injected with saline injections. Condyle-fossa relationship (CFR) spaces were measured in sagittal (SP) and frontal planes (FP) of images of cone-beam computed tomography (CBCT) done before (T0) and after 30 days' interventions (T1). Visual analogue scale (VAS) measured the patients' TMD pain perception (PP). Data were compared by generalized linear models considering the results over time (α = .05).

RESULTS

There were no statistical differences in CFR in the SP or FP for TG and CG over time (p ˃ .05), except for frontal lateral space CFR (p < .05). In both groups, the condyle was positioned medially after interventions. Frontal lateral space increased in TG for both, left and right sides, over time (p < .05), as well as PP decreased over time (p < .05) for TG and CG.

CONCLUSIONS

The results depicted that there was no significant association with BoNTA injection in TMD masseter muscles in PP and CFR, except considering the frontal lateral space of CFR.

CLINICAL RELEVANCE

BoNTA injection in the masseter muscles may not promote clinically significant shifts in the condyle-fossa relationships of muscular TMD patients.

Association Between Articular Eminence Structure and Joint Spaces in Temporomandibular Joints with Anterior Disc Displacement

BACKGROUND AND AIMS

The association among the joint spaces, articular eminence morphology, and disc displacement is not well documented in the literature. This study aims to evaluate and compare the joint spaces and the articular eminence structure (eminence height [Eh] and inclination [Ei]) using cone-beam computed tomography (CBCT) of temporomandibular joints (TMJs) with anterior disc displacements and joints with normal disc position.

METHODS

The study groups consisted of 75 TMJs of 39 patients. The disc status of TMJs was diagnosed with magnetic resonance imaging, and the measurements were performed on CBCT. Three groups, that is, normal disc position (NDP) group, anterior disc displacement with reduction (ADDWR) group, and anterior disc displacement without reduction (ADDWoR) group, were established. Anterior, superior, posterior joint spaces (AJS, SJS, and PJS, respectively), articular Eh, and articular Ei were measured. Statistical Package for the Social Sciences version 22 was used for statistical analysis. Shapiro-Wilk test was used to check the normality of data. Intergroup comparisons of categorical variables were assessed with Fisher-Freeman-Halton test. For comparison of continuous variables parameters, Mann-Whitney U test and Kruskal-Wallis test were used. Statistical significance level was determined as P < 0.05.

RESULTS

Significant differences were not found in intergroup comparisons for PJS. However, the difference between groups was found to be significant for AJS, SJS, Eh, and Ei. Intergroup comparisons were performed for these parameters. No significant difference was found between the NDP group and the ADDWR group for AJS, SJS, Eh, and Eİ. The mean AJS, SJS, Eh, and Ei values in ADDWoR were found to be significantly lower compared to the corresponding values in both NDP and ADDWR groups.

CONCLUSION

Decreased AJS and SJS when TMJ is evaluated with CBCT may be an indicator of ADDWoR. Authors suggest that narrowed articular Ei and reduced articular Eh can be one of the predisposing factors for anterior disc displacement.

Divergent chondro/osteogenic transduction laws of fibrocartilage stem cell drive temporomandibular joint osteoarthritis in growing mice

The anterior disc displacement (ADD) leads to temporomandibular joint osteoarthritis (TMJOA) and mandibular growth retardation in adolescents. To investigate the potential functional role of fibrocartilage stem cells (FCSCs) during the process, a surgical ADD-TMJOA mouse model was established. From 1 week after model generation, ADD mice exhibited aggravated mandibular growth retardation with osteoarthritis (OA)-like joint cartilage degeneration, manifesting with impaired chondrogenic differentiation and loss of subchondral bone homeostasis. Lineage tracing using Gli1-CreER+; Tmfl/-mice and Sox9-CreER+;Tmfl/-mice showed that ADD interfered with the chondrogenic capacity of Gli1+ FCSCs as well as osteogenic differentiation of Sox9+ lineage, mainly in the middle zone of TMJ cartilage. Then, a surgically induced disc reposition (DR) mouse model was generated. The inhibited FCSCs capacity was significantly alleviated by DR treatment in ADD mice. And both the ADD mice and adolescent ADD patients had significantly relieved OA phenotype and improved condylar growth after DR treatment. In conclusion, ADD-TMJOA leads to impaired chondrogenic progenitor capacity and osteogenesis differentiation of FCSCs lineage, resulting in cartilage degeneration and loss of subchondral bone homeostasis, finally causing TMJ growth retardation. DR at an early stage could significantly alleviate cartilage degeneration and restore TMJ cartilage growth potential.

Evaluation of Temporomandibular Joint in Patients with Parkinson's Disease: A Comparative Study

(1) The aim of this study was to perform an evaluation of the temporomandibular joint (TMJ) in patients with Parkinson's disease (PD) and present the morphological differences of the TMJ between healthy subjects and patients with PD. (2) A total of 102 Caucasian subjects were divided equally into two groups. The study group consisted of patients with PD, while the control group comprised healthy subjects. Ten parameters, including anterior joint space (AJS), superior joint space (SJS), posterior joint space (PJS), condyle head length (CHL), condylar neck width (CNW), minor axis of the condyle (MAC), long axis of the condyle (LAC), condylar axis inclination (CI), medial joint space (MJS), and lateral joint space (LJS), were measured using magnetic resonance images. The data were statistically analyzed using paired samples t-test and Student's t-test, with a significance level set at p < 0.05. (3) In the PD group, all TMJ parameters showed a statistically significant difference between both sides of the face (p < 0.05). However, in the control group, AJS, SJS, PJS, CHL, CNW, MAC, CI, MJS, and LJS did not show a statistically significant difference between both sides of the face (p > 0.05), except for LAC (p < 0.05). The asymmetry index values of AJS, SJS, PJS, CHL, CNW, MAC, CI, MJS, and LJS demonstrated a statistically significant difference between the study and control groups (p < 0.05), except for LAC (p > 0.05). (4) Within the limitations of this retrospective study, the findings suggest that TMJ morphology and asymmetry could be associated with PD.

CT-based retrospective cohort study for the evaluation of mandibular condylar dimensions - A pilot study

Background

The temporomandibular joint (TMJ) is a unique structure of the body where the mandible, one of the important facial bones, articulates with the temporal part of the skull bone. Obtaining morphometric dimensions for mandibular condyle is important for performing an accurate pre/postoperative assessment, planning temporomandibular and orthognathic surgeries, and applications in forensic sciences in context to the Indian population, which is presently based on dimensions of Caucasian population from available literature. Several investigators noticed the variation in the craniofacial morphology in different ethnic groups and vary according to age and sex. This study aims to provide the normal dimensions of the mandibular condyle in the Indian population, which would be providing racially specific values for diagnosis, treatment planning of surgeries involving condylar processes such as rigid internal fixation of TMJ region, congenital deformities, and customizing TMJ prosthesis concerning these measurements.

Aim of the Study

To measure the change in dimensions of mandibular condyle according to age and sex using computed topographic scan imaging.

Objectives of the Study

1. To measure the dimensions of mandibular condyle. 2. To evaluate any age-related changes in dimensions. of mandibular condyle (intercohort comparison). 3. To evaluate any sex-related changes in dimensions of mandibular condyle (intercohort comparison).

Materials and Methods

A retrospective analytical cohort study.

Inclusion Criteria

Indian adult males and females aged between 20 and 50 years who underwent facial computed tomography (CT) for any reason (e.g., head injury).

Exclusion Criteria

Patients with congenital or acquired dentofacial deformities involving TMJ.

Data Collection

By assessing the morphometric dimensions of condyle of mandible using CT scan images.

Result/Conclusion

Mean condylar dimensions for each age/sex cohort are established; however, no significant change as per age and sex in condylar dimensions in the Indian population is noted.

Quantitative and qualitative condylar changes following stabilization splint therapy in patients with temporomandibular joint disorders

OBJECTIVE

This study aimed to explore the quantitative and qualitative condylar changes following stabilization splint (S.S) therapy, including condylar position, morphology, and bone mineral density (BMD) in subjects with temporomandibular disorders (TMD).

MATERIALS AND METHODS

In this retrospective clinical study, we enrolled 40 TMD subjects (80 joints) aged 18 to 35 years, for whom a S.S was used to treat TMD. The 80 TMD consists of 32 masticatory muscle disorders (myalgia) and 48 TMJ disorders (arthralgia). Cone beam computed tomography (CBCT) was used to scan the TMJs of subjects pre- and post-treatment for three-dimensional analysis (3D). Using Mimics software v.21.0, quantitative (3D condylar and joint spaces dimensions parameters were measured using linear measurements in millimeters, according to the Kamelchuk method and Ikeda method, while the assessment of anteroposterior condyle position within the glenoid fossa was based on the method of Pullinger and Hollender), and qualitative (a round bone tissue with an area of 2 mm² in three representative areas according to the Kamelchuk method to measure condylar BMD) pre- and post-treatment. Intra- and inter-group statistical comparisons were performed using the Wilcoxon signed ranks and the Kruskal-Wallis test, respectively.

RESULTS

The course of treatment was 6-12 months, with an average of 9.1 months. For the pre- and post-treatment quantitative comparisons, there was a statistically significant difference in the anterior joint space (AJS) and coronal medial space, as well as the condyle length in the myalgia group and condylar width in the arthralgia group. For qualitative measurements, a significant difference was observed in the posterior slope of the myalgia group and the arthralgia group's anterior, superior, and posterior slopes. The inter-group comparisons revealed significant differences in AJS, condylar length, and anterior slope density.

CONCLUSION

In short-term follow-up, the S.S influenced patients with TMD from different origins; it changes anterior and coronal medial joint space, condyle length in myalgia, and width in arthralgia. Furthermore, it improved the condyle bone density more evidently in arthralgia.

CLINICAL RELEVANCE

This study highlights the influence of S.S on symptomatic populations with TMD of different origins from a qualitative and quantitative perspective.

Assessment of condylar positional changes in severe skeletal class II malocclusion after surgical-orthodontic treatment

OBJECTIVES

This study aimed to determine the positional changes in the condyle in the temporomandibular joint (TMJ) of severe skeletal class II malocclusion patients treated with surgical-orthodontics.

MATERIALS AND METHODS

The measurements of TMJ space in 97 severe skeletal class II malocclusion patients (20 males, 77 females, mean age, 24.8 years, mean ANB = 7.41°) were assessed using limited cone-beam computed tomography (LCBCT) images acquired before orthodontics (T0) and 12 months after surgery (T1). 3D remodeling of the TMJ and measurements of the anterior space (AS), superior space (SS), and posterior space (PS) were performed to determine the position of the condyle for each joint. All data were analyzed by t test, correlation analysis, and Pearson correlation coefficient.

RESULTS

The mean AS, SS, and PS values after the therapy changed from 1.684 to 1.680 mm (0.24%), 3.086 to 2.748 mm (10.968%), and 2.873 to 2.155 mm (24.985%), respectively. The decreases in SS and PS were statistically significant. Positive correlations were found in the mean AS, SS, and PS values between the right and left sides.

CONCLUSIONS

The combination of orthodontic and surgical treatment makes the condyle move counterclockwise in the TMJ in severe skeletal class II patients.

CLINICAL RELEVANCE

Studies of temporomandibular joint (TMJ) intervals changes in patients with severe skeletal class II after sagittal split ramus osteotomy (SSRO) are limited. The postoperative joint remodeling, resorption, and related complications remain unstudied.

Comparison of Mandibular Volume and Linear Measurements in Patients with Mandibular Asymmetry

In patients with mandibular asymmetry, the volume of the mandible divided by the mandibular median plane is significantly larger on the non-deviated (N-Dev) side than on the deviated (Dev) side. However, it has been reported that there is no significant difference between the volumes of the N-Dev and Dev sides when the mandibular ramus and body are divided. The purpose of this study was to investigate which region is responsible for the volume difference between the N-Dev and Dev sides. Cone Beam Computed Tomography (CBCT) images of patients with mandibular asymmetry were analyzed by measuring the volume, and linear analysis of the mandibular body, ramus, and condyle on the N-Dev and Dev side was performed. In this study, CBCT images of 37 patients (8 Japanese, 16 Korean, and 13 Egyptian) aged ≥ 18 years with mandibular asymmetry (men: 20, women: 17) were used to evaluate mandibular asymmetry. In patients with mandibular asymmetry, the N-Dev side showed significantly larger values than the Dev side for both volume and linear condyle, ramus, and mandibular body measurements. These results do not differ according to sex or ethnicity. Therefore, it is suggested that the N-Dev side of mandibular asymmetry is large without any regional specificity in pathophysiology.

Relationship between the Mandibular Condyle Position and the Bite Force in the People with Normal Temporomandibular Joint

Statement of the Problem. The mandibular condyle position is important in temporomandibular joint (TMJ) disorders. The bite force is a mechanical force that may affect the condylar position. Purpose. To investigate the relationship between condylar position in the glenoid fossa and maximum bite force in adults with normal temporomandibular joint. Materials and Methods. In this cross-sectional study, 23 subjects (21 females and 2 males; mean age 38.88 $\pm$ 11.7 years) with 41 joints participated. Right and left joints were examined using cone-beam computed tomography. Maximum bite force was measured using the strain gauge transducer in the regions of right molar, left molar, and incisors. Pearson correlation coefficient, paired sample t-test, and binary logistic regression were employed for analysis. Results. The mean maximum bite force was 169.09 ± 87.7 N. The most common position of the condyle was anterior (n = 36) and inferior (n = 31). The mean of mandibular condyle joint spaces for right and left sides were not statistically significant ( $P>0.05$ ). There were no relationships between the condylar positions and the mean maximum bite force ( $P>0.05$ ). Conclusion. The condylar positions in the glenoid fossa are not related to the bite force in the people with normal temporomandibular joint.

Three-Dimensional Assessment of Temporomandibular Joint Morphology and Facial Asymmetry in Individuals with Different Vertical Skeletal Growth Patterns

The aim of the current study was to investigate, by means of Cone-Beam Computed Tomography (CBCT), condyle−fossa relationship, temporomandibular joint (TMJ) morphology and facial asymmetry in subjects with different vertical skeletal growth patterns. CBCT of 56 patients (112 TMJs) were categorized into three groups according to the mandibular plane angle (MP): Hypodivergent (MP ≤ 23°), Normodivergent (23° < MP < 30°), and Hyperdivergent (MP ≥ 30°). TMJ spaces, width and depth of the condyle and thickness of the fossa were measured. Horizontal and vertical measurements were used to assess facial asymmetry. One-way Analysis of Variance (ANOVA) and post-hoc Turkey tests were computed for the between-groups comparison. Statistical significance was set at p < 0.05. Larger anterior joint space and smaller condylar dimensions (medio-lateral diameter and medio-lateral thickness) were observed in the hyperdivergent group compared to the normodivergent and hypodivergent groups. Right condylar distances to midsagittal plane were significantly larger than left distances in all the three groups. A vertical pattern of growth in healthy individuals seems to be associated with condylar position and dimension, while facial asymmetry values do not differ among different vertical groups.

Three-dimensional evaluation of mandibular condyle and coronoid process according to sex, age, and skeletal deformities

OBJECTIVE

To correlate the volume of the mandibular condyle (MC) and the coronoid process (CP) with sex, age, and skeletal deformities.

METHODS

The structures were visualized through semi-automatic segmentation of the 3D model and complemented with manual segmentation, using the ITK-SNAP 3.0 software. Mann-Whitney, Kruskal-Wallis, and the Dunn test were performed (p < 0.05).

RESULTS

The MC volume showed statistical differences between sex and skeletal deformities. Men and Class III patients showed higher values. CP volume was not influenced by age or skeletal deformities. However, statistical differences were found between sex, with higher values for men.

CONCLUSION

MC volume was influenced by sex and skeletal deformities, while CP was influenced only by sex. Women have smaller volumes for these structures. Age is not correlated with the volume of MC and CP. The highest and lowest values of condylar volume were found for Class III and II individuals, respectively.

Effects of occlusal splint and exercise therapy, respectively, for the painful temporomandibular disorder in patients seeking for orthodontic treatment: a retrospective study

OBJECTIVE

To evaluate the effect of hard stabilization splints (HSS), counselling and exercise therapies, respectively, for the painful temporomandibular disorder (TMD) in patients seeking for orthodontic treatment through magnetic resonance imaging (MRI) and clinical examination.

MATERIALS AND METHODS

Eighty-seven TMD patients were divided into two groups according to their therapies: the HSS group (n = 43) comprising of patients treated with HSS, counselling and masticatory muscle exercises; the control group (n = 44) comprising of patients treated with counselling and masticatory muscle exercises alone. All patients had orthodontic therapies after the first treatment phase. The joint pain and clicking of all patients were recorded via clinical examination. MRIs of HSS groups were taken before (T₀), after the first phase (T₁), and after the orthodontic treatment (T₂). Parameters indicating the condyles and articular discs were evaluated. Clinical symptom (pain and clicking) changes among T₀, T₁ and T₂ time point were detected in the two groups respectively. The significant differences between HSS and control groups, as well as between male and female were tested at T₁ and T₂. Position changes of condyles and discs in HSS group among T₀, T₁ and T₂ were detected in male and female respectively.

RESULTS

After the first treatment phase, there was no difference in the decrease of facial pain between the two group, as well as between male and female in the two groups (P > 0.05). Clicking decreasing was not statistically significant. After the whole orthodontic periods, the TMJ pain relapsed in female of the control group, and the number of female's pain joints was more than male's (P < 0.05). In the HSS group, the posterosuperior movements of discs and the anteroposterior movements of condyles were recorded in closing position (P < 0.05). After the whole orthodontic periods, female's disc-condyle angles increased, the discs to HRP distance decreased and condyles to VRP distance increased when compared with the data of T₁ (P < 0.05).

CONCLUSIONS

For the orthodontic patients with painful TMD, HSS combined with counselling and exercise therapies before orthodontic treatment could provide pain relief. HSS is helpful to improve the position and relation of discs and condyles. In addition, male's prognosis is better than female's in terms of stability.

Descriptions of the dynamic joint space of the temporomandibular joint

BACKGROUND

Clinical diagnosis and treatment depended heavily on the motion analysis of the human joints. Although the dynamic joint space (DJS) of other organs was widely used in academic investigations, they were not universally used in the temporomandibular joint (TMJ) field, which was also important for the motion evaluation of the TMJ. The objectives of this study are to introduce the DJS of the TMJ and characterize the DJS regulars of mandibular movements.

METHODS

Ten asymptomatic subjects were selected to instruct this application. The mouth opening and closing, mandibular protrusion, and left and right protrusions, were tracked by the optical motion tracking system. According to trajectories of markers and reconstructed models from computed tomography, the motions of the mandibles could be obtained. The DJSes, which were described as the minimum Euclidian distances, were subsequently calculated based on the geometrical surfaces between the condyle and fossa during the motions. Then, the DJS map could be drawn based on the calculated values.

RESULTS

The DJS map manifested a decreasing trend when the condyle crossed the glenoid fossa, while it generally increased after the condyle crossed the fossa during the mouth opening. The results showed that the average maximum and minimum anterior joint spaces were 5.39 mm and 2.07 mm during mouth opening respectively with a great discrepancy existing among the subjects. The average maximum and minimum anterior joint spaces were 4.74 mm and 2.19 mm during mandibular protrusion. As for left and right protrusions, the DJS of the contralateral side was greater than that of the ipsilateral side.

CONCLUSION

In comparison to morphological analyses or only mandibular motions, the DJS provides more dynamic and interactive information about the TMJ. The research and methodology may help us comprehend TMJ motions and temporomandibular disorders.

Assessment of thickness of roof of the glenoid fossa in dentate, edentulous, and partially edentulous subjects using cone beam computed tomography (CBCT) - a retrospective study

OBJECTIVES

Studies have inferred a direct association between Temporomandibular joint disorders (TMD) and the integrity of the structures associated with it such as the Glenoid fossa thereby necessitating the requirement to measure the thickness of this oft ignored entity. This study was carried out to assess the thickness of the glenoid fossa roof in dentulous, edentulous, and partially edentulous subjects using archival Cone beam computed tomography (CBCT) images.

METHOD

Analysis of CBCT data of 120 joints from 60 adult subjects without signs and symptoms of TMD was carried out. The scans were grouped based on the dental status as dentulous, edentulous, and partially edentulous and additionally into two sets as those below and above 40 years of age. The distance between the superior and inferior cortices of the glenoid fossa was measured indicating the thickness of the roof of the glenoid fossa in the coronal and sagittal planes, by three independent observers. Analysis of Variance (ANOVA) and Tukey's post hoc test were used to compare the association between the mean thickness of the glenoid fossa and the dentition status. A p ≤ 0.05 was considered to be significant.

RESULTS

There was no significant association between the mean thickness of the glenoid fossa and the dentition of the study participants of all three groups, when assessed by the three observers, except the mean thickness on the right side in the sagittal section as measured by one observer. A thicker fossa was observed in edentulous subjects when compared to dentulous participants, and the difference was statistically significant (p = 0.035).

CONCLUSION

The thickness of the roof of the glenoid fossa demonstrated no association with the dental status of the study participants and no age or sex related differences were noted.

Relationship between the condyle morphology and clinical findings in terms of gender, age, and remaining teeth on cone beam computed tomography images

Aim: This study aimed to evaluate the relationship between clinical findings and some factors such as age, gender, and remaining teeth on the anatomy of the temporomandibular joint in order to diagnose normal variations from abnormal cases. Methods: In this cross-sectional study, cone-beam computed tomography (CBCT) images of 144 patients referring to Tabriz Dental School for various reasons were selected and evaluated. The different aspects of the clinical parameters and the morphology of the condyle were evaluated on coronal, axial, and sagittal views. The CBCT prepared using the axial cross-sections had been 0.5 mm in thickness. The sagittal cross-sections had been evaluated perpendicular to the lengthy axis of the condyle at a thickness of 1 mm and the coronal cross-sections had been evaluated parallel to the lengthy axis of the condyle at a thickness of 1 mm. Data were analyzed with descriptive statistical methods and t-test, chi-squared test, using SPSS 20. The significance level of the study was p < 0.05. Results: There was a significant relationship between the condyle morphology, number of the teeth, and mastication side (p = 0.040). There were significant relationships between the condyle morphology, age between 20-40, and occlusion class I on the all the three views (coronal, axial, sagittal) (p = 0.04), (p = 0.006), (p = 0.006). Also, significant relationships were found in the condyle morphology and location of pain according to age, the number of remaining teeth, and gender. (p = 0.046) (p = 0.027) (p = 0.035). Conclusion: There are significant relationships between the clinical symptoms and condyle morphology based on age, gender, and the number of remaining teeth. The clinical finding that has the most significant relationship between the condyle morphology, remaining teeth (9-16 teeth), all of the age range (20-80 year), and gender was mastication side.

Analysis of the Volumetric Asymmetry of the Mandibular Condyles Using CBCT

Objectives

The aim of this study was to analyse volumetric asymmetries between the right and left condyles in relation to age, gender, and dental status.

Materials and methods

A retrospective analysis of 150 cone beam computed tomography (CBCT) scans was conducted. A single investigator performed the volumetric analysis of the CBCT scans using Vesalius 3D software. The volumetric data were analysed in relation to the gender, age, and dental status.

Results

The mean right condylar volume was significantly higher (P < .01) than the left condylar volume. Right and left condylar volumes were significantly higher (P < .01) in male study participants when compared to female study participants. There was no significant difference (P = .47) in the volumetric asymmetry between the male and female study participants. The volumetric asymmetry was significantly higher (P < .01) in the older age groups when compared to the younger age groups. The volumetric asymmetry was significantly higher (P < .01) in the partially and completely edentulous patients when compared to the dentate study participants. The condylar volume on the side having a partially edentulous area was significantly lower than the condylar volume of the contralateral dentate side (P < .001).

Conclusions

The volumetric asymmetry between the right and left condyle significantly increases with age and edentulousness. The result of the study encourages the clinicians to perform volumetric evaluation of the condyles in cases of radiographically evident condylar asymmetries to obtain a more accurate diagnosis.

Oval Type of Human Mandibular Condyle in Panoramic Radiographs of a Tertiary Care Centre: A Descriptive Cross-sectional Study

Introduction

Mandibular condyle is a prominent structure in the mandible, which forms the temporomandibular joint. An oval-shaped condyle is considered to be present with a normal temporomandibular joint and any morphological variation of the condyle is assumed to be pathologic in temporomandibular disorders. The aim of the study was to find out the prevalence of oval shaped mandibular condyle among orthopantomogram radiographs of patients visiting the tertiary care centre.

Methods

A descriptive cross-sectional study was performed among 752 condyles visiting a tertiary care center from November 29, 2021 to April 1, 2022. The ethical approval was taken from the Institutional Review Committee (Reference number: 184 (6-11) 078/079) before conducting the study. Convenience sampling was done. The radiographs were first examined and the observed morphological type of mandibular condyle was noted. Data analysis was done using Statistical Package for the Social Sciences version 22.0. Point estimate at 95% Confidence Interval was calculated along with frequency and proportion for binary data.

Results

The prevalence of oval shaped mandibular condyles out of 752 condyles was 416 (55.32%) (51.77-58.87 at 95% Confidence Interval). The oval-shaped condyle on the right side was 205 (54.52%) and on the left side was 211 (56.12%).

Conclusions

The prevalence of oval shaped condyles among patients in this study was similar to the studies done in similar settings.

Keywords

condyle; mandible; Nepal; X-ray.

Surgical Reduction of Chronic Bilateral Traumatic Dislocation of the Mandibular Condyles With Erosion of the Middle Fossa Floor: Case Report With Surgical Video

BACKGROUND

Dislocation of the mandibular condyle (MC) is not a common condition, but when a traumatic case involves erosion of the middle fossa floor, it becomes a much more complicated and even rarer pathology.

OBJECTIVE

To describe the management of traumatic dislocation of the MCs with erosion of the middle fossa floor. We provide a step-by-step surgical video demonstrating reestablishment of the condylar position and occlusion.

METHODS

A 65-yr-old woman with rheumatoid arthritis presented after a ground-level fall. She was admitted to the intensive care unit with simultaneous complex medical conditions, intubated, and medically treated for over a month. She was seen in outpatient follow-up 2 mo later and noted to have an anterior open bite and bilateral temporomandibular joint pain. Computed tomography of the face showed bilateral dislocation of the MCs with erosion of the middle fossa floor.

RESULTS

Open surgical treatment with bilateral eminectomies was performed to obtain adequate reduction, involving a multidisciplinary team including neurosurgery, oral-maxillofacial surgery, and otolaryngological surgery. She did well postoperatively.

CONCLUSION

Multiple factors predispose a patient to MC dislocation, but we believe the catalyst in this case was significant manipulation of the jaw during endotracheal intubation. A chronic postoperative open bite can lead to much more difficult treatment, given bony erosion and fibrotic tissue formation. This case highlights the challenges of diagnosis and treatment of a bilateral traumatic dislocation and provides a surgical video reference description of repair and resolution.

Volumetric analysis of normal condyles and those with disc displacement with reduction in the Indonesian population: A CBCT study

Purpose

Disc displacement can cause resorption of the head of the condyle and affect its volume. This study analysed the volume of normal condyles and those with disc displacement with reduction (DDR) in cone-beam computed tomography (CBCT) scans from the Indonesian population.

Materials and Methods

This study analysed 56 condyles (26 normal and 30 with DDR) from patients who visited the Oral and Maxillofacial Radiology Unit after being referred from the Prosthodontics Unit at Dental Hospital Universitas Padjadjaran from December 2020 to February 2021. Samples were divided into 2 groups (normal and DDR left and right-side condyles) based on the DC/TMD Axis 1 form through the clinical examination results. Both sample groups were exposed to CBCT radiation. The CBCT imaging results in the Digital Imaging and Communications in Medicine format were exported to the open-source ITK-SNAP format to determine condyle volume. Volumetric data from the cortical and trabecular areas of the right or left side condyles were arranged by sex. The independent t-test was used to determine the significance of differences with IBM SPSS version 21.0. Intra- and inter-observer reliability and validity were tested before determining the volume of the condyles.

Results

Normal condyles and DDR condyles showed significant differences in volume (P<0.05). Significant differences were also seen in cortical (P=0.0007) and trabecular (P=0.0045) volumes. There was a significant difference in condylar volume based on sex.

Conclusion

The normal condyle volume was significantly different from the DDR condyle volume in both sexes.

Three-dimensional morphological and biomechanical analysis of temporomandibular joint in mandibular and bi-maxillary osteotomies

Orthognathic surgery is a typical approach for treating maxillofacial deformities. However, orthognathic surgery results in positional changes in the condyles. In a previous review, the effects of orthognathic surgery on temporomandibular joints (TMJs) are not provided. Hence, in this study, we investigate the morphological changes in TMJs after mandibular and bi-maxillary osteotomies. The relationship between the morphological parameters of TMJs and symptoms of temporomandibular disorders (TMDs) is discussed. Finite element contact stress analysis is performed, and the results show that the two abovementioned surgeries can improve maxillofacial deformities, although the positions of the condyles are changed. Moreover, preoperative stress asymmetry of the left and right TMJs is observed, which remain after the surgeries. TMD patient-specific analysis shows that three joint spaces (medial joint space, lateral joint space, superior joint space) are significantly correlated with TMD symptoms.

Morphological Assessment of TMJ Spaces, Mandibular Condyle, and Glenoid Fossa Using Cone Beam Computed Tomography (CBCT): A Retrospective Analysis

Background  The temporomandibular joint (TMJ) is included in the category of ginglymoarthrodial synovial joints. The mandibular condyle plays a vital part in the development of the craniofacial complex. Hence, the evaluation and assessment of the condylar volume and its morphology are of utmost importance.

Aim  The aim of this research was to use cone beam computed tomography (CBCT) imaging modality to evaluate the morphology of the mandibular condyle and glenoid fossa in a selected population and document any morphometric changes.

Setting and Design  It is an observational study.

Materials and Methods  A retrospective CBCT analysis was performed on 119 patients. The length, width, height, linear measurements of the joint spaces (anterior, posterior, and superior), volume of the condyle, and roof of glenoid fossa thickness were evaluated on both the left and right sides in both males and females.

Results  The height, width, and length of mandibular condyle were significantly increased in males on both sides. Except for the left anterior space, all other spaces were significantly larger in males. Overall, the volume of the condyles in males was significantly increased on both sides.

Conclusion  CBCT can be a valuable diagnostic aid in the evaluation of various dimensions, joint spaces, and condylar volume in different planes and thus, can be a useful predictor in the assessment of treatment outcomes of disorders affecting the TMJ.

Radiographical investigation of the condylar position using three-dimensional imaging (a comparative Iraqi study)

Objective: To investigate the condylar position in an Iraqi sample of patients with temporomandibular joint disorders (TMDs) using cone beam computed tomography.Methods: The study included 20 patients with temporomandibular disorders and 20 healthy patients with normal temporomandibular joints (40 individuals in total). Reference landmarks from the sagittal aspect were used to measure various straight distances between the glenoid fossa and condyle, such as the anterior, posterior, and superior joint spaces. The inclination of the articular eminence was also evaluated.Results: There was a statistically significant difference in inclination in the TMD group when patients were categorized by sex. Males had larger superior space and inclination compared with females.Conclusion: Cone beam computed tomography can offer essential information about variations in the TMD group and can be used as one of the indicators for such variations for good diagnosis and treatment.

Differences in mandibular condyle and glenoid fossa morphology in relation to vertical and sagittal skeletal patterns: A cone-beam computed tomography study

Objective

This study aimed to evaluate the following null hypothesis: there are no differences in the morphology of the temporomandibular joint (TMJ) structures in relation to vertical and sagittal cephalometric patterns.

Methods

This retrospective study was performed with 131 participants showing no TMJ symptoms. The participants were divided into Class I, II, and III groups on the basis of their sagittal cephalometric relationships and into hyperdivergent, normodivergent, and hypodivergent groups on the basis of their vertical cephalometric relationships. The following measurements were performed using cone-beam computed tomography images and compared among the groups: condylar volume, condylar size (width, length, and height), fossa size (length and height), and condyle-to-fossa joint spaces at the anterior, superior, and posterior condylar poles.

Results

The null hypothesis was rejected. The Class III group showed larger values for condylar width, condylar height, and fossa height than the Class II group (p < 0.05). Condylar volume and superior joint space in the hyperdivergent group were significantly smaller than those in the other two vertical groups (p < 0.001), whereas fossa length and height were significantly larger in the hyperdivergent group than in the other groups (p < 0.01). The hypodivergent group showed a greater condylar width than the hyperdivergent group (p < 0.01). The sagittal and vertical cephalometric patterns showed statistically significant interactions for fossa length and height.

Conclusions

TMJ morphology differed across diverse skeletal cephalometric patterns. The fossa length and height were affected by the interactions of the vertical and sagittal skeletal patterns.

The influence of mandibular condyle morphology on TMJ anterior dislocations

OBJECTIVES

The present study was designed to investigate the correlation between the bony morphology of the mandibular condyle and the occurrence of temporomandibular joint (TMJ) idiopathic anterior dislocation.

STUDY DESIGN

A comparative retrospective study was conducted among 14 patients presenting idiopathic anterior dislocations (study group) and 15 patients who did not suffer from any TMJ disorders (control group). All patients underwent a multidetector computed tomography scan demonstrating the full extent of their joints. The scans of 58 joints were reconstructed and analyzed by tools available in Dolphine3 software. Mandibular condyle size and volume were measured, and its shape was characterized.

RESULTS

Shape, width, length, height, and volume of the mandibular condyles did not differ statistically between the study and control groups.

CONCLUSION

Mandibular condyle morphology does not affect TMJ idiopathic anterior dislocation.

Tracking-based deep learning method for temporomandibular joint segmentation

Background

The shape, size, and surface information relating to the glenoid fossae and condyles in temporomandibular joints (TMJ) are essential for diagnosing and treating. Patients with TMJ disease often have surface abrasion which may cause fuzzy edges in computed tomography (CT) imaging, especially for low-dose CT, making TMJ segmentation more difficult.

Methods

In this paper, an automatic segmentation algorithm based on deep learning and post-processing was introduced. First, U-Net was used to divide images into 3 categories: glenoid fossae, condyles, and background. For structural fractures in these divided images, the internal force constraint of a snake model was used to replenish the integrity of the fracture boundary in a post-processing operation, and the initial boundary of the snake was obtained based on the basis of the tracking concept. A total of 206 cases of low-dose CT were used to verify the effectiveness of the algorithm, and such indicators as the Dice coefficient (DC) and mean surface distance (MSD) were used to evaluate the agreement between experimental results and the gold standard.

Results

The proposed method is tested on a self-collected dataset. The results demonstrate that proposed method achieves state-of-the-art performance in terms of DCs = 0.92±0.03 (condyles) and 0.90±0.04 (glenoid fossae), and MSDs =0.20±0.19 mm (condyles) and 0.19±0.08 mm (glenoid fossae).

Conclusions

This study is the first to focus on the simultaneous segmentation of TMJ glenoid fossae and condyles. The proposed U-Net + tracking-based algorithm showed a relatively high segmentation efficiency, enabling it to achieve sought-after segmentation accuracy.

The Short-Term Effect of Active Skeletonized Sutural Distractor Appliance on Temporomandibular Joint Morphology of Class III Malocclusion Subjects

Objectives  The purpose of this study was to evaluate the short-term effect of active skeletonized sutural distractor (ASSD) appliance on temporomandibular joint morphology of class III malocclusion subjects.

Materials and Methods  This was a prospective interventional study. Cone-beam computerized tomography (CBCT) images of 22 patients were taken before and after treatment by using Planmeca Promax 3D CBCT machine version 2.9.2 (Planmeca OY Helsinki, Finland). The condylar width, height, length, roof of glenoid fossa thickness, and all joint spaces were measured. The condylar position was determined based on Pullinger and Hollander formula. The condylar shape was determined as per Kinzinger et al. The condylar volume was calculated by using Mimics software (Materialize, Belgium).

Statistical Analysis  Data analysis was performed by using SPSS software version 24. Wilcoxon paired signed-rank test was used to compare the difference in temporomandibular joint morphology and condylar volume between pre- and post-treatment measurements. Chi-square test was used to compare the condylar position and shape.

Results  The superior ( p = 0.000 on the right side, p = 0.005 on the left side) and posterior joint spaces ( p = 0.000 on both sides) were decreased after the treatment, respectively. The condyles were rotated upward and backward, thereby increasing the anterior joint spaces ( p = 0.000 on both sides) after the treatment. The condylar volume increases after treatment, but no significant differences were observed ( p = 0.903 on the right side, p = 0.062 on the left side).

Conclusion  The significant changes were observed in joint spaces. The condyles were more anteriorly placed before treatment. Condylar position and shape alter in response to ASSD treatment. The condylar volume did not show any significant change.

[Cone-beam CT evaluation of temporomandibular joint in skeletal class Ⅱ female adolescents with different vertical patterns]

OBJECTIVE

To compare temporomandibular joint (TMJ) morphology and position among skeletal class Ⅱ female adolescents with different vertical patterns using cone-beam CT (CBCT).

METHODS

Diagnostic CBCT images of 80 female patients aged 11 to 14 years were assessed retrospectively. According to subspinale-nasion-supramental angle (ANB) and Frankfort horizontal plane-gonion-gnathion angle (FH-GoGn), the participants were categorized into four groups (20 subjects each), i.e. class Ⅰ normal angle (group 1, 0°≤ANB < 4°, 22°≤FH-GoGn≤32°), class Ⅱ low (group 2, ANB≥4°, FH-GoGn < 22°), normal (group 3, ANB≥4°, 22°≤FH-GoGn≤32°) and high angle (group 4, ANB≥4°, FH-GoGn > 32°). Cephalometrics, morphology and position of TMJ were measured in Dolphin software. Using paired-samples t test to analyze TMJ symmetry, One-way analysis of variance (One-way ANOVA) and Chi-square tests to detect differences among the groups. The correlations between cephalometrics and TMJ measurements were also analysed within the skeletal class Ⅱ patients.

RESULTS

(1) Analysing TMJ morphologic symmetry, some measurements differed statistically although the mean diffe-rences were negligibly relative to their values. No statistically significant difference was found among the groups though group 4 showed the highest probability of condylar position asymmetry (65%). (2) Comparing group 1 with group 3, statistical difference was found in condylar position (χ2=6.936, P < 0.05) instead of morphologic measurements. Anterior and concentric condylar position were more frequently observed in group 1, yet posterior position was more prevalent in group 3. (3) In groups 2, 3, and 4, statistically, group 2 had the deepest glenoid fossa depth (H2&4=10.517, P=0.002), biggest superior (LSD-t2&3=3.408, LSD-t2&4=5.369, P < 0.001) and lateral (LSD-t2&3=2.767, LSD-t2&4=3.350, P=0.001) joint spaces, whereas group 4 showed the shortest condylar long axis diameter (H2&4=13.374, P < 0.001), largest glenoid fossa vertical distance (LSD-t2&4=4.561, P < 0.001, LSD-t3&4=2.713, P=0.007), smallest medial (LSD-t2&4=-4.083, P < 0.001) and middle (LSD-t2&4=-4.201, P < 0.001) joint spaces. The posterior condylar position proportion gradually increased from groups 2 to 3 to 4. Correlation analysis revealed ANB correlated with anterior joint space positively (r=0.270, P=0.037) and condylar long axis angle negatively (r=-0.296, P=0.022). FH-GoGn correlated with superior (r=-0.488, P < 0.001), posterior (r= -0.272, P=0.035), mesial (r=-0.390, P=0.002), middle (r=-0.425, P=0.001), and lateral (r=-0.331, P=0.010) joint spaces, articular eminence inclination (r=-0.259, P=0.046), as well as condylar long axis diameter (r=-0.327, P=0.011) negatively, and glenoid fossa depth (r=0.370, P=0.004) positively.

CONCLUSION

TMJ characteristics of skeletal class Ⅱ sagittal pattern mainly reflected in condylar position rather than morphology. TMJs of different vertical patterns differed more in joint spaces, position of condyle and glenoid fossa than in morphologic measurements. Vertical position of glenoid fossa and proportion of posterior condyle increased gradually from hypodivergent to hyperdivergent. Highest glenoid fossa position, maximum ratio of posterior positioned condyle, smallest joint spaces, shallowest glenoid fossa depth, and narrowest condylar long axis diameter were found in skeletal class Ⅱ high angle group, which means that patients with this facial type have considerable joint instable factors, and we should especially pay attention when orthodontic treatment is carried out on them.

[Cone-beam CT evaluation of temporomandibular joint in skeletal class Ⅱ female adolescents with different vertical patterns]

OBJECTIVE

To compare temporomandibular joint (TMJ) morphology and position among skeletal class Ⅱ female adolescents with different vertical patterns using cone-beam CT (CBCT).

METHODS

Diagnostic CBCT images of 80 female patients aged 11 to 14 years were assessed retrospectively. According to subspinale-nasion-supramental angle (ANB) and Frankfort horizontal plane-gonion-gnathion angle (FH-GoGn), the participants were categorized into four groups (20 subjects each), i.e. class Ⅰ normal angle (group 1, 0°≤ANB < 4°, 22°≤FH-GoGn≤32°), class Ⅱ low (group 2, ANB≥4°, FH-GoGn < 22°), normal (group 3, ANB≥4°, 22°≤FH-GoGn≤32°) and high angle (group 4, ANB≥4°, FH-GoGn > 32°). Cephalometrics, morphology and position of TMJ were measured in Dolphin software. Using paired-samples t test to analyze TMJ symmetry, One-way analysis of variance (One-way ANOVA) and Chi-square tests to detect differences among the groups. The correlations between cephalometrics and TMJ measurements were also analysed within the skeletal class Ⅱ patients.

RESULTS

(1) Analysing TMJ morphologic symmetry, some measurements differed statistically although the mean diffe-rences were negligibly relative to their values. No statistically significant difference was found among the groups though group 4 showed the highest probability of condylar position asymmetry (65%). (2) Comparing group 1 with group 3, statistical difference was found in condylar position (χ²=6.936, P < 0.05) instead of morphologic measurements. Anterior and concentric condylar position were more frequently observed in group 1, yet posterior position was more prevalent in group 3. (3) In groups 2, 3, and 4, statistically, group 2 had the deepest glenoid fossa depth (H_2&4=10.517, P=0.002), biggest superior (LSD-t_2&3=3.408, LSD-t_2&4=5.369, P < 0.001) and lateral (LSD-t_2&3=2.767, LSD-t_2&4=3.350, P=0.001) joint spaces, whereas group 4 showed the shortest condylar long axis diameter (H_2&4=13.374, P < 0.001), largest glenoid fossa vertical distance (LSD-t_2&4=4.561, P < 0.001, LSD-t_3&4=2.713, P=0.007), smallest medial (LSD-t_2&4=-4.083, P < 0.001) and middle (LSD-t_2&4=-4.201, P < 0.001) joint spaces. The posterior condylar position proportion gradually increased from groups 2 to 3 to 4. Correlation analysis revealed ANB correlated with anterior joint space positively (r=0.270, P=0.037) and condylar long axis angle negatively (r=-0.296, P=0.022). FH-GoGn correlated with superior (r=-0.488, P < 0.001), posterior (r= -0.272, P=0.035), mesial (r=-0.390, P=0.002), middle (r=-0.425, P=0.001), and lateral (r=-0.331, P=0.010) joint spaces, articular eminence inclination (r=-0.259, P=0.046), as well as condylar long axis diameter (r=-0.327, P=0.011) negatively, and glenoid fossa depth (r=0.370, P=0.004) positively.

CONCLUSION

TMJ characteristics of skeletal class Ⅱ sagittal pattern mainly reflected in condylar position rather than morphology. TMJs of different vertical patterns differed more in joint spaces, position of condyle and glenoid fossa than in morphologic measurements. Vertical position of glenoid fossa and proportion of posterior condyle increased gradually from hypodivergent to hyperdivergent. Highest glenoid fossa position, maximum ratio of posterior positioned condyle, smallest joint spaces, shallowest glenoid fossa depth, and narrowest condylar long axis diameter were found in skeletal class Ⅱ high angle group, which means that patients with this facial type have considerable joint instable factors, and we should especially pay attention when orthodontic treatment is carried out on them.

Morphometric evaluation of the temporomandibular joint on cone-beam computed tomography

INTRODUCTION

Evaluation of the temporomandibular joint (TMJ) pathologies with cone-beam computed tomography (CBCT) provides essential information about the bone structures of the TMJ. It is important to know the normal reference range when defining these pathologies. The aim of this study is to examine the morphometric and morphologic analyses of the bone structures of TMJ on the CBCT images in detail according to age, gender, and joint side.

MATERIAL AND METHODS

A total of 35 parameters related to the condylar process, articular tubercle, mandibular fossa, ramus of mandible, and joint space were examined on the CBCT images. These parameters were compared with the joint sides and gender, and correlated with age.

RESULTS

Thirty-five parameters were evaluated. A statistically significant difference was found between genders in 22 parameters and joint sides in 6 parameters. When the correlation of parameters with age was examined; it was found that there was a very weak positive relationship in nine parameters, a weak positive relationship in one parameter, and a very weak relationship in the negative direction in two parameters.

CONCLUSION

In this study, the condylar process, articular tubercle, mandibular fossa, ramus of mandible, and joint spaces, which are usually examined separately in the literature, were examined, and the normal reference range was determined for all these parameters. We think that these normal reference ranges will be useful for researchers interested in TMJ pathologies.

Cone beam computed tomography findings in temporomandibular joint of chronic qat chewers: Dimensional and osteoarthritic changes

The social habit of chewing qat (also known as khat) is widely practised in East Africa and the Arabian Peninsula. It has been linked with various oro-facial conditions, including temporomandibular joint disorders (TMD). This cross-sectional, comparative study sought to investigate the effects of qat chewing on temporomandibular joint (TMJ), using cone beam computed tomography (CBCT). A total of 85 Yemeni males were included. The participants were divided into two groups: Qat chewers (QC; n = 41) and non-qat chewers (NQC; n = 44). Relevant data were obtained using a structured questionnaire and standardised clinical examination. Additionally, CBCT images of the TMJs were obtained, and then, osteoarthritic changes and TMJ dimensions were analysed. SPSS 21 was used for statistical analyses, with a significant level was set at 0.05. Compared to NQC, a significantly higher proportion of QC presented with clinical signs of TMDs. The qualitative CBCT findings revealed significantly higher osteoarthritic changes in QC than in NQC: osteophyte (51.2% vs 22.7%; P = .008), subcortical sclerosis (48.8% vs 27.3%; P = .047), articular surface flattening (46.3% vs 6.8%; P = .009) and subcortical cysts (43.9% vs 4.5%; P < .001). However, CBCT quantitative findings (condylar dimensions) did not show significant differences between the two groups. The chewing side of the QC group showed slightly more changes compared to the non-chewing side. The results demonstrate that qat chewing has detrimental effects on TMJ manifested mainly as osteoarthritic changes. Further large-scale studies are recommended.

Volumetric and morphological analysis of condyle and glenoid fossa on computed tomography

AIM

The aim of this study was to evaluate temporomandibular joint (TMJ) condyle and glenoid fossa morphology with measurements on Computed Tomography (CT) and volumetric analysis using InVesalius software program.

MATERIALS AND METHODS

250 condyles in 125 patients (mean age: 40.64) was evaluated on CT. Length, width, and height of the condyle, condylar volume, the thickness of glenoid fossa (TGF), condyle surface area, anterior space (AS), superior space (SS), and posterior space (PS) were measured in this study. Two left and right sides of the jaw have been measured. Linear measurements were performed with the image analysis program (Image J, 1.4 v version, National Institutes of Health, Bethesda, MD). Volume and surface area measurements were performed with InVesalius software (CTI, Campinas, SãoPaulo, Brazil).

RESULTS

To compare the dimensions of the condyle between males and females, there was only a significant difference in left AS and SS and no significant difference was found between males and females in other measured factors. There was a significant difference between the age groups and left SS. A significant difference was also found between the age groups and condylar height, condyle surface area, and condylar volume on both right and left sides.

CONCLUSION

Evaluation of condylar morphology is important to assess the TMJ anomalies and bony changes. This study showed no significant differences between gender and all measured factors except in the left AS and SS. However, age factor had a major effect on the morphology.

Incidental Findings in Temporomandibular Joint Region Detected by Cone-beam Computed Tomography: A Retrospective Study

Purpose:

The purpose of this study was to investigate the prevalence of Incidental Findings (IFs) in the temporomandibular joint (TMJ) region detected in Cone-Beam Computed Tomography (CBCT) scans of maxilla and mandible.

Materials and Methods:

In this study, 384 CBCT scans were reviewed for IFs of the TMJ region. Demographic data including age and sex were recorded. The scans were evaluated in multiplanar views: corrected sagittal, corrected coronal and axial sections. IFs in TMJ region were categorized into eight groups: osteoarthritis, flattening and erosion of condyle and articular eminence, osteophytes, subchondral pseudocyst, condyle hyperplasia, condyle hypoplasia, bifid condyle, and soft tissue calcification. Statistical analyses were performed using the SPSS statistic v.22.

Results:

From the CBCT scans, a total of 81 (21.1%) IFs were identified. 184 of the subjects (47.9%) were male and 200 (52.1%) were females. Their age ranged from 10 to 75 years old with a mean of 36.8 and a standard deviation of 13.9 years. The most frequent IFs were flattening and erosion of condyle and articular eminence (40.74%), followed by soft tissue calcification (30.86%). Osteoarthritis was not observed in any of the subjects. There was no significant difference between females and males in IFs of TMJ joint and its related structures. Flattening and erosion of condyle and articular eminence, soft tissue calcification, osteophytes and, subchondral pseudo cyst showed significant differences between individuals of different age ranges.

Conclusion:

While examining CBCT images, it is critical to check for evidence of IFs in the TMJ region. The findings of this study emphasize the value of a thorough examination of all areas visualized on CBCT scans even those beyond the region of interest.

2D-3D comparison of the temporomandibular joint in skeletal Class II versus Class I adults: A retrospective study

OBJECTIVE

To compare the temporomandibular joint (TMJ) morphological characteristics in people with Class II versus Class I sagittal skeletal relationship and to identify other factors that influence the TMJ dimensions.

MATERIAL AND METHODS

This cross-sectional and retrospective study evaluated 188 people divided into two groups, 92 cone-beam computed tomographies (CBCTs) and lateral radiographs (LR) of people with Skeletal class II relationship with Class II division 1 malocclusion versus 96 CBCTs and LR of people with Class I skeletal relationship and Class I malocclusion (controls). The CBCTs included people of both sexes, aged between 15 and 65 years old. The 3D Imaging Carestream Software was used to evaluate the condyle height and neck width, mediolateral and anteroposterior condyle dimensions, the shape of the glenoid fossa and condyle in the CBCTs. Likewise, the ANB angle, the Wits appraisal and other measurements were evaluated on LR. Besides, Mann-Whitney U, Chi² and multiple linear regression tests were performed. The significance level was set at P˂0.05.

RESULTS

The mediolateral and anteroposterior condyle dimensions were smaller in class II people (1.82mm and 0.29mm, respectively) than class I people (P<0.05). Likewise, height and neck width of condyle were smaller in class II people (0.73mm and 0.40mm, respectively) than class I people (P<0.05). Multiple linear regression identified mainly the ANB angle as a factor (P<0.05) that influenced the dimensions, decreasing the condyle dimensions in skeletal class II relationship.

CONCLUSIONS

People with skeletal class II relationship showed smaller condyle dimension values than class I people. A decrease in the dimensions of the eminence and the condyle could be expected when the ANB angle increases.

Are Signs of Degenerative Joint Disease Associated With Chin Deviation?

PURPOSE

Degenerative joint changes commonly affect the temporomandibular joint (TMJ) and can result in chin deviation. However, the extent of degenerative TMJ changes and chin deviation has not been well-characterized. The present study sought to correlate degenerative TMJ changes with condylar volume, grayscale measures, and chin deviation.

MATERIALS AND METHODS

The present cross-sectional study had enrolled women with skeletal Class III malocclusion. Cone-beam computed tomography scans were acquired preoperatively. For each condyle, degenerative TMJ signs were analyzed and the condylar volume and grayscale were measured. The predictor variable was the presence of degenerative TMJ signs, classified as categorical data: 0, if none; 1, only present in 1 joint; and 2, present in both joints. The primary outcome variable was a chin deviation of 3 mm or more. Other associated variables were grouped by age, cephalometric data, and 3-dimensional condylar measurements. Descriptive bivariate statistics were computed, and univariate and multiple logistic regression analyses were conducted to identify any associations between degenerative TMJ disease and chin deviation.

RESULTS

We included 85 patients, who were classified into 2 groups: less than 3 mm of chin deviation (n = 43) and 3 mm or more of chin deviation (n = 42). The presence of more than 10 degenerative TMJ signs was significantly associated with the presence of 3 mm or more of chin deviation (P < .001). In multiple regression models, the presence of subcortical sclerosis in 1 joint and in both joints (adjusted odds ratio [OR], 3.698; 95% confidence interval [CI], 1.051 to 13.012; adjusted OR, 5.001; 95% CI, 1.461-17.119, respectively) correlated significantly with the presence of 3 mm or more of chin deviation (P < .05). The volume difference between the 2 condyles was significantly greater in the group with more than 10 degenerative TMJ signs and 3 mm or more of chin deviation than in the group with 10 or fewer degenerative TMJ signs and less than 3 mm of chin deviation (P = .016 and P < .001, respectively).

CONCLUSIONS

In women with skeletal Class III malocclusion, the presence of more than 10 degenerative TMJ signs increased the prevalence of 3 mm or more of chin deviation. The presence of subcortical sclerosis in either 1 or both joints and volume differences between the 2 condyles were associated with greater chin deviation.

Semi-automated three-dimensional volumetric evaluation of mandibular condyles

OBJECTIVES

The aim of this study is to research the mandibular condyle volumes of the Turkish subpopulation by sex, age, laterality, and posterior occlusal support, to provide volumetric data for young and old patient groups.

METHODS

The CBCT images of 690 condyles from 345 patients (165 females and 180 males) were assessed. Patients aged 18-25 years were chosen for the younger group, and 45-70 years for the older group. The dental statuses of the older patient group were divided into three categories, based on the Eichner index. All the CBCT images were transferred to the three-dimensional volumetric analysis software, ITK-Snap (Penn Image Computing and Science Laboratory (PICSL) at the University of Pennsylvania and Scientific Computing and Imaging Institute (SCI) at the University of Utah) and analyzed with sagittal, coronal, and axial sections. Mandibular condyles were defined using semi-automatic segmentation, then manual segmentation was performed to ensure accuracy. Analyses were performed using MedCalc statistical software. The p value < 0.05 was considered statistically significant.

RESULTS

The mean right condyle volume for the whole sample (n = 345) was 1678.8 mm³ and the left condyle volume was 1661.3 mm³. Males had a larger condyle volume than females in both the younger and older patient groups (p = 0.035, p < 0.01, respectively). The Eichner index did not correlate significantly with condylar volume in the older patient group (p = 0.134, p = 0.122).

CONCLUSION

There were significant differences between the volumes of mandibular condyles for different sex, while there were no significant differences in relation to age, laterality, and posterior occlusal support.

Three-dimensional analysis of temporomandibular joint in Chinese adults with normal occlusion and harmonious skeleton

OBJECTIVE

This study aimed to analyze the detailed three-dimensional measurements of temporomandibular joint (TMJ) in Chinese adults with normal occlusion and harmonious skeleton.

METHODOLOGY

In 51 subjects 102 joints were analyzed using Anatomage Invivo dental 5.4. The measurements include: joints' parameters, position, angulation, and inclination of the condyle and articular fossa as well as 3D volumetric of the joint-spaces. All measurements were statistically analyzed by paired Student's t test to find out the differences between the left- and right sides. Pearson correlation coefficient test was done to figure out the relationship of the TMJ parts in the normal situation.

RESULTS

The inter-condyle distances medially, geometrically, and laterally were 90.2 ± 5.2,107 ± 6.1, and 125 ± 5.5 mm, respectively. However, the 102 condyles were angulated on three planes 54.9º ± 11.2, 71.8º ± 7.3, and 12.5º ± 6.3 at vertical-, horizontal-, and midsagittal planes, respectively. The joint spaces measurements were 2.6 ± 0.7 mm, 2.5 ± 0.8 mm, 2.4 ± 0.7 mm, and 3.3 ± 0.7 mm for anterior-, medial-, posterior-, and superior joints, respectively. The total volume of the whole joint-space was 404.3 ± 71mm³. The left condyle position was on the centric position whereas the right condyle was eccentric (slightly anterior).

CONCLUSION

Chinese subjects are characterized by wide inter-fossa distance and inter-condyle distance; however, no significant correlations with joint spaces in normal occlusion were found. The asymmetries between right- and left mandibular condyle were distinguished in angular and linear-vertical measurements. Finally, this study could be considered as reference data for upcoming research in the Chinese population.

Cone beam computed tomographic assessment of mandibular condyle in Kennedy class I patients

OBJECTIVES

The aim of this study was to assess the dimensional and volumetric changes in the mandibular condyle in Kennedy class I patients versus completely dentate patients by cone beam computed tomography (CBCT) to estimate the effect of loss of posterior teeth on the mandibular condyle.

PATIENTS AND METHODS

This study was performed on one hundred patients requesting CBCT scans: fifty Kennedy class I patients and fifty fully dentate controls. Condyle dimensions mesio-distal, cranio-caudal and antero-posterior as well as condyle volume were measured in both the groups.

RESULTS

Kennedy class I patients showed statistically significant higher mean condyle width but lower mean condyle height than the control group. No statistically significant difference was found between the study group and the control group regarding condyle AP dimension. There was no statistically significant difference between condyle volumes in the two groups.

CONCLUSION

Loss of posterior teeth is accompanied by significant decrease in condyle height and increase in condyle width with no change in the total condyle volume or antero-posterior dimensions.

Effects of Low-Intensity Pulsed Ultrasound Therapy on the Temporomandibular Joint Complex in Conjunction With a Fixed Functional Appliance: A Prospective 3-Dimensional Cone Beam Computed Tomographic Study

OBJECTIVES

This prospective study aimed to analyze 3-dimensional changes in the temporomandibular joint (TMJ) complex with a synergistic effect of functional jaw orthopedics using a fixed functional appliance and low-intensity pulsed ultrasound (LIPUS) therapy.

METHODS

Forty patients with skeletal class II malocclusion were randomly assigned to 4 groups (2 control groups and 2 test groups) of 10 patients each. After insertion of the fixed functional appliance, the test group was stimulated with LIPUS therapy in the TMJ region bilaterally for 20 minutes daily for first 10 days and thereafter at least 3 times per week until complete mandibular advancement was achieved. Three-dimensional images obtained with a cone beam computed tomographic scanner were used to analyze the changes in the TMJ complex at the prefunctional stage and after completion of functional appliance therapy. Direct intragroup and intergroup comparisons for different morphometric variables were conducted with the Student t test.

RESULTS

The 40 patients included 20 male and 20 female patients between the ages of 12 and 16 years (mean age ± SD, 13.2 ± 1.8 years). Both the test groups and the control groups showed statistically significant variable changes in condylar head position and morphometric changes in relation to the joint space analysis (mean differences, -1.000 and -1.080 mm; P < .05). However, no significant differences were found during the intergroup comparisons at the prefunctional and postfunctional stages for the variables examined, except for the measurements of the linear distance of the condyle to the external auditory meatus on both the right and left sides at the prefunctional phase.

CONCLUSIONS

Low-intensity pulsed ultrasound therapy positively affects the quantum of the joint space, thus proving to be a promising adjunct in enhancing treatment outcomes of functional jaw orthopedics in growing patients with skeletal class II malocclusions.