Comparative cone-beam computed tomography evaluation of the osseous morphology of the temporomandibular joint in temporomandibular dysfunction patients and asymptomatic individuals

Positional and dimensional TMJ characteristics in different temporomandibular disorders: A cross-sectional comparative study

OBJECTIVE

To investigate the morphological and positional temporomandibular joint (TMJ) characteristics of different temporomandibular disorders (TMDs).

METHODS

One hundred forty-three TMD patients were divided into three groups: Group 1: Myalgia (M), Group 2: Disc displacement with reduction (DDWR), and Group 3: Disc displacement without reduction (DDWOR). Three-dimensional positional and dimensional parameters of the TMJ, including mandibular fossa, condyle, and TMJ spaces were evaluated using cone beam computed tomography (CBCT). The significance level was p < 0.05.

RESULTS

Mandibular condyles were significantly positioned in more vertical, posterior, and medial directions, with the reduced condylar width in the DD groups (p < 0.001). Anterior joint space was significantly higher in the DDWR group than the myalgia group; the superior joint spaces were more reduced in DD groups than the myalgia group.

CONCLUSION

Patients diagnosed with disc displacement showed significantly different condylar positions and joint spaces compared to the myalgia group in a skeletally comparable sample.

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.

Relationships between functional temporomandibular joint space and disc morphology, position, and condylar osseous condition in patients with temporomandibular disorder

OBJECTIVE

To investigate the correlations between joint space and temporomandibular joint (TMJ) components and the compressive states of the disc and condyle subsequent to joint space changes.

MATERIALS AND METHODS

A total of 240 TMJs were categorized according to disc morphology, disc position, and condylar osseous condition. The two-dimensional (2D) and three-dimensional (3D) measurements were compared. The functional joint space (FJS) and disc areas on closed- and open-mouth images (DA-C and DA-O) were also calculated, and the joint space was measured in five directions. Different groups of TMJ components were compared. A spring model was used to simulate the effect of condylar displacement on the disc and condyle.

RESULTS

Disc morphology was strongly correlated with its position. The measurements were equivalent between 2D and 3D methods. DA-C and FJS differed significantly between groups. The DA-C to FJS ratio differed between the Class 2 and Class 3 groups and between disc displacement groups with and without reduction. Altered disc morphology and position were correlated with significant changes in joint space in the 60°, 90°, and 120° directions. Despite minor discrepancies among condylar osseous conditions, reduced joint space was correlated with bone destruction at the corresponding site. The spring model stimulation revealed that condylar displacement caused elevated stresses on the disc and condyle.

CONCLUSIONS

Condylar displacement causes joint space alterations while exerting compressive pressure on both the disc and condyle.

CLINICAL RELEVANCE

Proper condylar positioning within the fossa is recommended to ensure sufficient articular disc accommodation.

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.

The relationship between the oblique sagittal temporomandibular joint disc position and the volume surface area of the condyle in young TMD adults

The present study aims to compare the volume surface area of the condyle, the horizontal condylar axial angle and the disc-condyle angle between temporomandibular disorder (TMD) and asymptomatic volunteers, explore and analyze the relationship between the temporomandibular joint (TMJ) disc position in oblique sagittal plane and the volume surface area of the condyle in young adults with TMD symptoms. 84 young adult volunteers were received TMJ examination by Magnetic Resonance Imaging (MRI) and Cone Beam Computed Tomography (CBCT). TMD and asymptomatic volunteers were 42 each. MRI was used to assess the position of TMJ disc in the oblique sagittal plane with the condyle apex method. CBCT data were used for three-dimensional (3D) reconstruction of condyle and the measurements of the horizontal condylar axial angle and the volume surface area of the condyle. The condylar volume surface area of the TMD group was smaller than that of the asymptomatic group (p < 0.05), the disc condyle angle was larger than that of the asymptomatic group (p < 0.05), and no significant difference was found in the horizontal condylar axial angle (p > 0.05). In terms of correlation, the volume surface area of the condyle were negatively correlated with the position of the articular disc in TMD patients (p < 0.05). This significant negative correlation suggests that the possibility of disc displacement can be considered when poor condylar morphology is found.

Assessment of condylar anatomy and degenerative changes in temporomandibular joint disorders - A scoping review

Temporomandibular disorders (TMDs) are a group of conditions that cause pain and dysfunction in the temporomandibular joint (TMJ) and muscles that control mandibular movement. In most cases, the etiology is unclear and is considered multifactorial. Recent research suggests that some forms of TMD could be associated with specific TMJ morphological characteristics. This study aims to provide a review of the reported anatomical and degenerative morphological condylar characteristics of subjects with a clinical diagnosis of TMD as described with the use of CBCT imaging, as well as the detection of potential predisposing anatomical factors. This review was developed and reported in accordance with the PRISMA-ScR Checklist. A comprehensive search was performed in five databases. Reports were screened by two independent reviewers based on preselected inclusion and exclusion criteria. 45 studies were included in this review. The most frequently reported degenerative changes associated with TMD were condylar surface erosion, flattening, osteophytes, and sclerosis. Anatomical characteristics included a small condylar size and a posterior position of the condylar head in the TMJ. The anterosuperior area of the condylar head appears to be the most frequently affected. More studies are required to determine potential specific predisposing anatomical characteristics.

Condylar Positional Changes in Skeletal Class II and Class III Malocclusions after Bimaxillary Orthognathic Surgery

Orthognathic surgery is indicated to modify the position of the maxillomandibular structure; changes in the mandibular position after osteotomy can be related to changes in the position of the mandibular condyle in the articular fossa. The aim of this study was to determine changes produced in the mandibular condyle 6 months after orthognathic surgery. A cross-sectional study was conducted that included subjects who had undergone bimaxillary orthognathic surgery to treat dentofacial deformity of Angle class II (group CII) or Angle class III (group CIII). Standardized images were taken using cone-beam computed tomography 21 days before surgery and 6 months after surgery; measurement scales were used to identify the condylar position and its relations with the anterior, superior, and posterior joint spaces. The results were analyzed using the Shapiro-Wilk and Student's t-tests, while considering a value of p < 0.05 as indicating a significant difference. Fifty-two joints from 26 patients, with an average age of 27.9 years (±10.81), were analyzed. All subjects in both group CII and group CIII showed a significant change in the anterior, superior, and posterior joint spaces. However, postoperative changes in the position of the condyle in the articular fossa were not significant in the anteroposterior analysis. We conclude that orthognathic surgery causes changes in the sagittal position of the mandibular condyle in subjects with mandibular retrognathism and prognathism.

Dimensional and positional temporomandibular joint osseous characteristics in normodivergent facial patterns with and without temporomandibular disorders

OBJECTIVE

This study evaluated the dimensional and positional osseous temporomandibular joint features in normodivergent facial patterns with and without temporomandibular disorders.

METHODS

A total of 165 adult patients were divided into two groups: group 1 (n = 79 patients; 158 joints): temporomandibular disorders patients and group 2 (n = 86 patients; 172 joints): non-temporomandibular disorders patients. Three-dimensional positional and dimensional temporomandibular joint characteristics, including glenoid fossa, mandibular condyles, and joint spaces, were assessed by cone beam computed tomography.

RESULTS

The glenoid fossa positions in the three orthogonal planes and height showed statistical significance between the two studied groups. The temporomandibular disorders patients showed higher horizontal and vertical condyle inclinations while anteroposterior inclination was less, and the condyle was positioned more superior, anterior, and lateral in the glenoid fossa. The condyle width and length showed no significance between the two groups, while condyle height was smaller in temporomandibular disorders patients. Anterior and medial joint spaces increased while the superior and posterior joint spaces reduced in temporomandibular disorders patients.

CONCLUSION

There were significant differences between the patients with and without temporomandibular joint disorders in terms of mandibular fossa positions and height as well as condylar positions and inclinations in horizontal and vertical planes together with reduced condylar height and reduced posterior and superior joint spaces in the temporomandibular disorders patients.

CLINICAL RELEVANCE

The temporomandibular disorder is a multifactorial disorder in which one of these factors is the dimensional and positional characteristics of the temporomandibular joints; including or excluding this factor requires a comprehensive three-dimensional investigation of patients with TMD compared to the normal group under the condition that the facial pattern is average as a confounding factor.

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.

Evaluation of congruency of condyle convexity and fossa concavity and interrelationship bony components in temporomandibular joint anterior dislocation

OBJECTIVES

This study aimed to compare the congruency of surface geometry of the articulating bones and morphologic differences in temporomandibular joint (TMJ) structure, between patients with TMJ anterior dislocation and healthy controls.

METHODS

The study included 15 patients with TMJ anterior dislocation and 15 controls who underwent cone-beam computed tomography. The surface angle of the articular fossa (fossa-concavity) and condyle (condyle-convexity) and joint spaces were measured from both sagittal and coronal views. The articular eminence morphology and horizontal condyle position were also evaluated.

RESULTS

Coronal fossa angles were significantly lower in controls than in patients (p < 0.05). There was a positive correlation between coronal condyle and fossa angle values in controls and in patients' joints (p < 0.05), however, the fossa-condylar congruence was higher in controls than in patients. Superior joint space was significantly higher in controls than in patients (p < 0.05). There were no significant differences in articular eminence measurements, mean condyle angle variables and condyle position between the patients and controls (p > 0.05).

CONCLUSIONS

The findings of this study which include lower joint congruency, higher fossa concavity and superior joint space distance in patients with anterior dislocation may be related to the inferior positioning of the condyle away from the fossa and potentially the elongation of the capsular ligament.

Comparison of imaging findings of 714 symptomatic and asymptomatic temporomandibular joints: a retrospective study

BACKGROUND

The correlation between temporomandibular disorders (TMD) and imaging features remains unclear. This study compared the cone beam computed tomography (CBCT) and magnetic resonance imaging (MRI) features in the temporomandibular joints (TMJs) with and without TMD symptoms.

METHODS

The participants were recruited from the TMJ Diagnosis and Treatment Center from March 2022 to September 2022. Condylar morphology and condylar position were evaluated by CBCT. Disc morphology, disc position, and joint effusion were evaluated by T2-weighted image of MRI. The Chi-Square test and binary logistic regression analysis were carried out.

RESULTS

Eighty-two patients with bilateral symptoms, 196 patients with unilateral symptoms, and 79 asymptomatic participants received MRI and CBCT examination. There were significant differences in the distribution of sex, age, condylar morphology, condylar position, disc morphology, disc position, and joint effusion in symptomatic and asymptomatic TMJs (P < 0.05), which showed a positive correlation with symptoms (P < 0.05). In multiple logistic regression, 19-30-year-age group, > 30-year-age group, abnormal condylar morphology, posterior condylar position, disc displacement with reduction (DDWR), and disc displacement without reduction (DDWoR) were found to be statistically significant (P < 0.05). The odds of having symptomatic TMJ were 1.952 higher in the 19-30-year-age group and 1.814 higher in the > 30-year-age group when compared to those aged ≤ 18-year-age group. The odds of having symptomatic TMJ were 2.360 higher in persons with abnormal condylar morphology when compared to those with normal condylar morphology. The odds of having symptomatic TMJ were 2.591 higher in persons with posterior condylar position when compared to those with the normal condylar position. The odds of having symptomatic TMJ were 2.764 higher in persons with DDWR and 4.189 higher in persons with DDWoR when compared to those with normal disc position. The area under the curve of the model was 0.736 ± 0.019 (95% CI 0.700-0.773, P = 0.000), which indicated that the model has a good fitting effect.

CONCLUSIONS

The imaging findings of TMJs were significantly different between symptomatic and asymptomatic TMJs. TMD is affected by multiple factors including > 19-year-age, abnormal condylar morphology, posterior condylar position, DDWR, and DDWoR, which could be risk factors for the development of TMD symptoms. Trial registration This study was retrospectively registered on 28/03/2022 and endorsed by the Ethics Committee of Affiliated Stomatology Hospital of Guangzhou Medical University (LCYJ2022014).

Analysis of the relationship between condylar changes and anterior disc displacement with reduction: a preliminary study

OBJECTIVES

To predict temporomandibular joint (TMJ) anterior disc displacement with reduction (ADDWR) from condylar shape, position, and dimensions obtained from CBCT images.

METHODS

This cross-sectional study was performed on 17 patients suffering from temporomandibular disorders diagnosed by history taking according to the chart of the American Association of orthodontists, clinical examination according to the Helkimo index and MRI. CBCT and MRI examinations were performed within one-week interval. Disc position, diagnosed by MRI was used as the gold standard. TMJs with posterior disc displacement or anterior disc displacement without reduction were excluded. Qualitative and quantitative analyses were performed on CBCT images to find the correlation between condylar variables and ADDWR. A logistic regression model was created to estimate ADDWR from condylar dimensions (height, width and depth).

RESULTS

Condylar shape and condylar position in the glenoid fossa were significantly correlated with ADDWR (P < 0.05). Condylar width, height and depth were significantly smaller in condyles with ADDWR compared to condylar dimensions in normal disc position. Logistic regression analysis could be used to predict the probability of anterior disc displacement with reduction from condylar dimensions.

CONCLUSION

Condylar shape, position, and dimensions assessed by CBCT are significantly correlated with ADDWR of the TMJ. Substituting the values of condylar width, height and depth in the equation suggests the probability of ADDWR.

Evaluation of the temporomandibular joint morphology and condylar position with cone-beam computerized tomography in patients with internal derangement

OBJECTIVES

To evaluate the relationship between internal derangement and morphological features of the temporomandibular joint by comparing joint morphology between patients with ID and control patients.

METHODS

The current study prospectively is evaluated the cone-beam computed images of 106 ID patients and 122 patients with asymptomatic joints; recorded angular and linear measurements. The relationships between these measurements and ID are investigated; the differences between the two groups using paired t tests.

RESULTS

There were significant differences in the values of articular slope and the condyle height/glenoid fossa depth (CH/GFD) ratio between patients in the ID and control groups (p < 0.05). There was also a relationship between these parameters and the gender of patients with ID. The condylar position was posterior in the ID group.

CONCLUSION

Posteriorly and superiorly located condyles with an increased CH/GFD ratio, condyles located eccentrically, and a steeper posterior slope may be risk factors for ID.

Occlusal Splint Therapy Combined with Cranio-Temporomandibular Kinesiotherapy in Patients with Temporomandibular Disorders-A CBCT Study

Occlusal splints are used as a non-invasive treatment for patients diagnosed with temporomandibular disorders (TMD). Another non-invasive treatment option for TMD patients is kinesiotherapy, which may be used alone or in conjunction with occlusal splint therapy. The aim of this study was to evaluate the changes in the intra-articular spaces of the temporomandibular joint (TMJ) after occlusal splint therapy combined with cranio-temporomandibular kinesiotherapy in TMD patients. Twenty-four patients (N = 24) diagnosed with TMD according to Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) were included. Cone beam computed tomography (CBCT) images were taken before and after treatment. The anterior, superior, posterior, and medial joint spaces were measured on the CBCT images, and the condylar ratio was calculated using Pullinger and Hollender's formula. Additionally, the thickness of the glenoid fossa (GFT), condylar medio-lateral widths (MLW), and condylar height (HCo) were measured. The condylar ratio was significantly higher after treatment (p = 0.049). The changes in dimensions of the anterior, superior, posterior and medial joint spaces were not statistically significant after treatment. No statistically significant differences were found in the dimensions of the GFT, MLW, and HCo post treatment. The condylar position did not shift anteriorly in a statistically significant way after occlusal splint therapy combined with cranio-temporomandibular kinesiotherapy in TMD patients.

A comparative study of condyle position in temporomandibular disorders patients with chewing side preference using cone-beam computed tomography

BACKGROUND

Chewing side preference (CSP) could cause structural and morphological changes of temporomandibular joint (TMJ) and has been suggested as one etiology of temporomandibular disorders (TMDs), but the condylar position in TMD patients with CSP is unknown.

OBJECTIVE

To compare the condylar position in the TMD patients with and without CSP.

METHODS

Ninety TMD patients with unilateral symptom (69 with CSP and 21 without CSP) and 20 asymptomatic participants received cone-beam computed tomography. The condylar position was determined based on the measurements of sagittal joint spaces. Intergroup and intragroup comparisons of the condylar position were performed.

RESULTS

The condyles in asymptomatic participants located nearly randomly in anterior, centric, and posterior positions. Patients without CSP had significantly more posterior condyles than asymptomatic participants (57.1% vs 30.0%, P<0.05). In patients with CSP, 50.7% of the condyles on the preferred chewing side and 42.0% on the unpreferred side located posteriorly, reaching no significant level compared with the asymptomatic participants and patients without CSP (P>0.05). The symptomatic joints and asymptomatic joints in patients with CSP and without CSP showed no significant differences in condylar position. While patients without CSP had significantly more posterior condyles in symptomatic joints than asymptomatic participants (P<0.05), patients with CSP showed a trend towards more posterior condyles in symptomatic joints compared with the asymptomatic participants (53.6% vs 30.0%, P=0.054).

CONCLUSION

Condylar position is not a strong indicator to differentiate CSP-related TMDs from none-CSP-related TMDs. Posterior condyle could not be viewed as one indicator of TMD.

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.

Imaging of the temporomandibular joint

Temporomandibular disorders are common, especially in young to middle-aged women, and most settle with supportive treatment. Imaging is indicated for the small percentage of cases that do not respond to conservative management and when the diagnosis is no doubt. The temporomandibular joint (TMJ) is a bilateral synovial articulation between the mandible and skull base. It has an intra-articular disc dividing the joint into superior and inferior compartments and the articular surfaces are lined with fibrocartilage. The normal imaging anatomy of the TMJ is described and illustrated. Different movements occur in each joint compartments: a hinge movement in the inferior joint space and translation or gliding in the superior joint space. Internal derangement is the commonest disorder affecting the TMJ and is most commonly due to disc displacement, followed by osteoarthritis and inflammatory arthritides. The imaging findings, primarily on magnetic resonance imaging (MRI) and computed tomography (CT), of internal derangement and less common disorders of the joint, are reviewed and illustrated. Optimal imaging protocols are discussed with detailed reporting guidelines.

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.

Temporomandibular Joints' Morphology and Osteoarthritic Changes in Cone-Beam Computed Tomography Images in Patients with and without Reciprocal Clicking-A Case Control Study

Background: Patients referred for orthodontic treatment often present symptoms of temporomandibular joints’ disorders (TMD), predominantly clicking. The objective was to analyze the morphology of the temporomandibular joints in cone-beam computed tomography (CBCT) images based on the presence of reciprocal clicking before orthodontic treatment. Methods: 105 participants took part in the study. 210 temporomandibular joints (TMJs) were allocated into one of two groups regarding the presence of reciprocal clicking. Morphology of condyle’s head, glenoid fossa, and articular eminence as well as condylar head position in the glenoid fossa and osteoarthritic changes in the area of the condylar head were examined for each TMJ in the CBCT images. Statistical analysis was performed with STATISTICA version 12.0. The following tests were performed: U-Mann Whitney, Kruskal-Wallis, t-Student, and chi-square. The statistical significance level was p = 0.05 for all the measurements included. Results: Significantly smaller condylar A-P dimension (p = 0.040) characterized temporomandibular joints with reciprocal clicking. Condyles were substantially more often positioned posteriorly (p = 0.043) and were significantly more often accompanied by subcortical cysts and pathologic osteoarthritic bone changes (p < 0.001). Conclusions: The early stages of internal derangements stay with alterations in morphology and position of TMJs as well as with the presence of osteoarthritic changes.

Temporomandibular joint osteoarthritis at Chelechol ra Orrak, Palau

OBJECTIVE

To explore the frequency and severity of temporomandibular joint osteoarthritis (TMJ-OA) and its causative factors in a skeletal assemblage from the prehistoric site of Chelechol ra Orrak, Palau, western Micronesia.

MATERIALS

50 temporomandibular joint surfaces (mandibular condyles and articular eminences), representing a minimum of 22 adult individuals, 17 of which retain teeth.

METHODS

Joint surfaces were macroscopically evaluated for characteristics associated with TMJ-OA and joint morphology. Dental remains were scored for tooth wear and staining.

RESULTS

Nine individuals (40.1 %) displayed lesions typical of TMJ-OA. The strongest associations were between tooth wear and TMJ-OA.

CONCLUSIONS

Indirect effects of parafunctional dental activity appear to be a factor in TMJ-OA frequency at Chelechol ra Orrak. While betel nut chewing may be one of those activities, it does not appear to be solely driving the presence of TMJ-OA.

SIGNIFICANCE

This study highlights the association between a specific parafunctional use of the temporomandibular joint and the potential pathological consequences. It also reinforces the need to carefully evaluate the archaeological context of skeletal remains in order to evaluate specific etiological factors in the presence of TMJ-OA in present and past populations.

LIMITATIONS

Sample sizes are limited in this study. This will increase as excavations continue.

SUGGESTIONS FOR FURTHER RESEARCH

Because dental occlusion appears to be associated with TMJ-OA, focus on dental conditions affecting occlusal patterns, such as third molar agenesis, antemortem tooth loss, and malocclusion, and their relationship to TMJ-OA frequency, are recommended.

Comparative cone-beam computed tomography evaluation of temporomandibular joint position and morphology in female patients with skeletal class II malocclusion

Objective

This study was performed to evaluate the position and morphology of the temporomandibular joint in female patients with skeletal class II malocclusion and to investigate the association between temporomandibular joint disorders and facial types using cone-beam computed tomography.

Methods

A lateral cephalogram was taken to determine the skeletal class of each participant. Sixty female patients aged 16 to 28 years were divided into high-angle, low-angle, and control groups. The shape of the condyle–fossa was measured and assessed on cone-beam computed tomography images of the 120 temporomandibular joints.

Results

Some condylar shape measurements displayed statistically significant differences among the groups. No significant differences were found in the length of the condyle, width of the glenoid fossa, or height of the articular eminence among the three groups. The posterior condylar position was more frequently observed in the low-angle group, whereas the anterior condylar position was more prevalent in the high-angle group.

Conclusion

The present study revealed differences in the condyle–fossa morphology and position in female patients with skeletal class II malocclusion with different vertical facial types.

Clinical guidelines for dental cone-beam computed tomography

Dental cone-beam computed tomography (CBCT) received regulatory approval in Japan in 2000 and has been widely used since being approved for coverage by the National Health Insurance system in 2012. This imaging technique allows dental practitioners to observe and diagnose lesions in the dental hard tissue in three dimensions (3D). When performing routine radiography, the examination must be justified, and optimal protection should be provided according to the ALARA (as low as reasonably achievable) principles laid down by the International Commission on Radiological Protection. Dental CBCT should be performed in such a way that the radiation exposure is minimized and the benefits to the patient are maximized. There is a growing demand for widespread access to cutting-edge health care through Japan's universal health insurance system. However, at the same time, people want our limited human, material, and financial resources to be used efficiently while providing safe health care at the least possible cost to society. Japan's aging population is expected to reach a peak in 2025, when most of the baby boomer generation will be aged 75 years or older. Comprehensive health care networks are needed to overcome these challenges. Against this background, we hope that this text will contribute to the nation's oral health by encouraging efficient use of dental CBCT.