Comparison of condylar size among different anteroposterior and vertical skeletal patterns using cone-beam computed tomography

OBJECTIVES

To compare condylar size among different anteroposterior and vertical skeletal patterns using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

The study included 166 subjects (61 men, mean age: 27.2 ± 7.6 years; 105 women, mean age: 27.4 ± 9.2 years). The anteroposterior skeletal patterns of the subjects were classified into Classes I (-1° ≤ A point-nasion-B point angle [ANB] < 4°), II (ANB ≥ 4°), and III (ANB < -1°). The vertical skeletal patterns were classified into hypodivergent (mandibular plane [MP] ≤ 23°), normodivergent (23° < MP < 30°), and hyperdivergent (MP ≥ 30°) groups. The condylar length, height, and width were examined using CBCT images. Analysis of covariance was used to compare three condylar size measurements among the three anteroposterior groups and the three vertical groups using sex as a covariate. Both left and right sides were examined. Nine groups were further divided according to the anteroposterior and vertical groups, and two-way analysis of covariance (ANCOVA) was applied to estimate the composite effect of skeletal patterns in both directions.

RESULTS

Sex as a covariate showed statistical significance in most examinations. The condylar height on both sides had statistically different anteroposterior skeletal patterns ( P < .001). The condylar width on both sides also had statistically different vertical skeletal patterns ( P < .001). After adjusting for sex, the condylar height and width on both sides increased from Class II, Class I, and Class III. The condylar width on both sides increased from the hypodivergent group, the normodivergent group, and the hyperdivergent group. No composite effect of skeletal patterns in both directions was observed.

CONCLUSIONS

Condylar height and width considerably differed among subjects with different anteroposterior or vertical skeletal patterns. The anteroposterior or vertical skeletal patterns independently affected the condylar size.

Effect of Rapid Maxillary Expansion on Condyle-fossa Relationship in Growing Patients

AIM

This study tests whether rapid maxillary expansion (RME) exerts long term effects on interglenoid fossa distance and condyle fossa relationship.

MATERIALS AND METHODS

Consecutive growing patients aged 8 to 13 years were allocated either to the RME group or control group. Cone-beam computed tomography was performed at baseline and at 6 months. Specific software was used to determine fixed landmarks. Multivariate Analysis of Covariance (MANCOVA) models were used, with time by group interaction, using age as a covariate.

RESULTS

Twenty-seven patients with a mean age of 11.4 ± 1.5 years were included. There was an overall significant group by time interaction (p = 0.012, effect size 0.59). Change in the lateral position of the glenoid fossa, the primary outcome, was reached (p = 0.008, effect size 0.258). Change in the laterolateral position of the center of the condyle, and the co-primary outcome was also significant (p = 0.011, effect size = 0.24). Nasal cavity width increased (p = 0.065, effect size = 0.14). There was an initial asymmetry in the horizontal position of the condyles that was carried on with no effect of RME.

CONCLUSION

Rapid maxillary expansion (RME) produces a significant increase in the interglenoid fossa distance and displacement of the mandibular condyles at 6 months in growing patients compared to a control group.

CLINICAL SIGNIFICANCE

The current study shows that RME is effective during growth, widening the interglenoid fossa distance and the lateral positions of the condyles and eventually enlarging the nasal cavity, without causing asymmetry.

Bilateral Condylar Hyperplasia-Nonsurgical Management: A Clinical Report

Background: Patients present with malocclusions in the form of bilateral open bite with functional and esthetic challenges. These are particularly so whereby these are acquired through growth anomalies that create a change in the occlusal status whereby a patient has to adapt to the challenge of the occlusal change. While surgical intervention is a considered option to correct such changes, not all patients are willing to endure the consequences of this intervention and as such this report presents a conservative minimally invasive approach. Aim: This clinical report demonstrates a nonsurgical approach in the management of a patient with bilateral metabolically active condylar hyperplasia. Case report: The patient presented with a bilateral open bite with occlusal contacts only present on her second molars. The severity of the open bite was reported to be recently progressing and getting worse. This condition had impaired her chewing function and quality of life over an 8-year period. Bone scintigraphy was performed and metabolically active bilateral condylar hyperplasia was diagnosed. The patient refused surgical intervention and instead a conservative overlay denture was prescribed, which successfully restored her function and esthetics. Conclusion: Removable overlay dentures can be a relatively simple and effective treatment option for patients presenting with newly acquired bilateral open bites to give a functional and esthetic outcome. Clinical significance: This clinical report shows the conservative management of bilateral condylar hyperplasia with a simple removable overlay appliance. The occlusion has stabilized and the patient functions well. Keywords: Bone scintigraphy, Condylar hyperplasia, Open bite, Overlay denture.

Collaborative treatment for a case of condylar hyperplastic facial asymmetry

Facial asymmetry can be caused by unilateral condylar hyperplasia. In such cases, it may be difficult to achieve symmetry since there is dentoalveolar compensation on the affected side, and the occlusal cant does not correspond to the frontal mandibular deviation. In the case presented, surgical orthodontic treatment and orthognathic surgery planning was accomplished for a patient with facial asymmetry due to condylar hyperplasia. The surgical plan was devised with particular attention to the severe dentoalveolar compensation. In this case, prior to the two-jaw surgery, the occlusal cant and frontal mandibular plane inclination was corrected through impaction of the left molar region by segmental osteotomy. Facial asymmetry and severe dentoalveolar compensation were successfully corrected after a unilateral segmental osteotomy and two-jaw surgery, resulting in a stable occlusal relationship and facial symmetry as well as good jaw function. Collaboration between the orthodontists and maxillofacial surgeons was essential for the successful treatment of the patient.

Cone-beam computed tomography evaluation on the changes in condylar long axis according to asymmetric setback in sagittal split ramus osteotomy patients

OBJECTIVE

To determine whether the condylar rotation is affected by asymmetric setback in patients undergoing sagittal split ramus osteotomy.

MATERIALS AND METHODS

Thirty patients who underwent bilateral sagittal split ramus osteotomy setback surgery were divided into the two groups, symmetric setback and asymmetric setback, according to the right/left difference of setback amount (<2.0, ≥2.0 mm). Condylar long axis changes were evaluated using the three-dimensional superimposition of before and immediately after surgery cone-beam computed tomography volume images. Evaluations were performed separately in lesser setback and greater setback side in patients undergoing asymmetric setback, whereas both side condyles were evaluated together in patients undergoing symmetric setback. Condylar axis changes on axial view were correlated with setback amount or right/left setback difference using Pearson correlation analysis.

RESULTS

In general, the condylar axis change occurred in a pattern of inward rotation. The condyles in patients undergoing symmetric setback showed 3.4° rotation in average. In case of asymmetric setback, the lesser setback side showed larger value (4.3°) than the greater setback side (2.3°) with a statistical significance. In the correlation analysis, setback amount showed no significant correlation with the condylar axis changes in both groups. However, correlation with right/left setback difference showed a positive correlation in lesser setback side of patients undergoing asymmetric setback.

CONCLUSION

The findings of this study indicate that large amount of setback alone does not contribute to the change in condylar long axis, but asymmetric setback might cause a change in condylar long axis, particularly on the lesser setback side.

Degenerative Disease of the Temporomandibular Joint and Pain-Dysfunction Syndrome

It is proposed that pain-dysfunction syndrome and degenerative disease ofthe temporomandibular joint may both be expressions of the same problem, i.e, repetitive overload of the joint system. Acceptance of this proposal will explain the contrasting, although often successful, methods of treatment.

Digital diagnosis and treatment of mandibular condylar fractures based on Extensible Neuro imaging Archive Toolkit (XNAT)

Objectives

The treatment of condylar fractures has long been controversial. In this paper, we established a database for accurate measurement, storage, management and analysis of patients’ data, in order to help determine the best treatment plan.

Methods

First of all, the diagnosis and treatment database was established based on XNAT, including 339 cases of condylar fractures and their related information. Then image segmentation, registration and three-dimensional (3D) measurement were used to measure and analyze the condyle shapes. Statistical analysis was used to analyze the anatomical structure changes of condyle and the surrounding tissues at different stages before and after treatment. The processes of condylar fracture reestablishment at different stages were also dynamically monitored. Finally, based on all these information, the digital diagnosis and treatment plans for condylar fractures were developed.

Results

For the patients less than 18 years old with no significant dislocation, surgical treatment and conservative treatment were equally effective for intracapsular fracture, and had no significant difference for neck and basal fractures. For patients above 18 years old, there was no significant difference between the two treatment methods for intracapsular fractures; but for condylar neck and basal fractures, surgical treatment was better than conservative treatment. When condylar fracture shift angle was greater than 11 degrees, and mandibular ramus height reduction was greater than 4mm, the patients felt the strongest pain, and their mouths opening was severely restricted. There were 170 surgical cases with condylar fracture shift angel greater than 11 degrees, and 118 of them (69.4%) had good prognosis, 52 of them (30.6%) had complications such as limited mouth opening. There were 173 surgical cases with mandibular ramus height reduction more than 4mm, and 112 of them (64.7%) had good prognosis, 61 of them (35.3%) had complications such as limited mouth opening.

Conclusions

The establishment of XNAT condylar fracture database is helpful for establishing a digital diagnosis and treatment workflow for mandibular condylar fractures, providing new theoretical foundation and application basis for diagnosis and treatment of condylar fractures.

Determination of sex differences of human cadaveric mandibular condyles using statistical shape and trait modeling

The objective of this study was to elucidate sex differences in the anatomy of human temporomandibular joint mandibular condyles using a statistical shape and trait model (SSTM). Mandibles were obtained from 16 human cadavers (79±13years). The condyles were scanned using micro-computed tomography with 27μm resolution. An image processing algorithm was used to segment the bone, determine the border of the entire mandibular condyle and trabecular bone compartments, and create triangulated meshes of the compartments. One subject was chosen as the template and was registered to the other individuals using a coherence point drift algorithm. This process positioned all vertices at corresponding anatomic locations. For the trabecular bone region, around each vertex position, the average bone image intensity, which is proportional to bone density, and microstructural traits, including trabecular bone volume fraction, thickness, separation, connectivity, and connectivity density were calculated. For the entire mandibular condyle mesh, the surface vertices were extracted to represent the overall anatomy of the condyle. Using a SSTM, the shape and trait information was reduced to a small set of independent and uncorrelated variables for each individual. Wilcoxon rank sum tests were used to test for differences in the variables between sexes. A lasso approach was used to determine a set of variables that differentiate between sexes. Male condyles were on average larger than female condyles, with complex differences in the microstructural traits. Two out of 15 principal components were statistically different between males and females (p<0.1). The lasso approach determined a set of 7 principal components that fully described the complex shape and trait differences between males and females. A SSTM was able to determine sex-dependent differences in the shape of the mandibular condyle. These differences may alter the biomechanics of the joint and contribute to the development of temporomandibular joint disease.

Simple bone cyst: rare incidental finding in the mandibular condyle by cone beam computed tomography

The simple bone cyst (SBC) is a benign intraosseous lesion that is considered to be a pseudocyst because the cystic cavity does not present an epithelial lining. The most accepted theory regarding its etiology is that the SBC develops when the blood clot fails to organize subsequent to bleeding caused by trauma. The SBC is asymptomatic, and therefore the diagnosis is made through routine imaging examinations. In imaging examinations, the lesion is characterized by a radiolucent, unilocular, well-delimited appearance and an irregular or scalloped contour with or without a sclerotic halo. This case report describes an SBC in the mandibular condyle region, discovered incidentally on imaging examinations.

Impact of Temporomandibular Joint Discectomy on Condyle Morphology: An Animal Study

PURPOSE

Temporomandibular disorders lead to parafunctional activity that may alter bone remodeling of mandibular components. This animal study aimed to assess the impact of temporomandibular joint discectomy on condylar bone microarchitecture.

MATERIALS AND METHODS

A total of 30 one-month-old Wistar rats were assessed and divided into 3 equal groups (2 test groups and 1 control group) of 10. The first test group underwent disc removal, the second test group underwent disc and condylar cartilage removal, and the 10 remaining rats were analyzed as sham-operated controls, following a split-mouth design. The rats were killed humanely 2 months after surgery, and the respective mandibles were scanned with micro-computed tomography for quantitative morphometric analysis.

RESULTS

There were significant differences among the 3 groups analyzed (disc removal, disc and condylar cartilage removal, and sham-operated control) for bone volume fraction (ratio of bone volume to total volume, P = .044), structure model index (P < .001), fractal dimension (P = .024), and porosity (P = .023). In addition, operated and contralateral nonoperated sides significantly differed for all variables in at least 1 of the test groups (P < .05) but not in the control group (P > .05).

CONCLUSIONS

Within the limitations of this study, our results suggest that discectomy may lead to alterations of the mandibular condylar morphology.

Association Between Missing Posterior Teeth and Occurrence of Temporomandibular Joint Condylar Erosion: A Cone Beam Computed Tomography Study

PURPOSE

To determine a possible association between asymptomatic temporomandibular joint (TMJ) condylar erosion and the number of missing posterior teeth and their location, as well as the number of dental quadrants with missing posterior teeth.

MATERIALS AND METHODS

This case-control study involved 210 patients (male to female ratio = 98:112) aged 16-74 years, with 105 asymptomatic patients with TMJ condylar erosion and a control group of 105 patients without TMJ condylar erosion. Cone beam computed tomography images were evaluated to classify the severity of TMJ condylar erosion as grade 0 (absence of erosion), grade I (slight erosion), grade II (moderate erosion), or grade III (extensive erosion).

RESULTS

The number of missing posterior teeth (mean ± standard deviation [SD]; 2.7 ± 2.4 vs 0.7 ± 1.2) (P < .001), number of dental quadrants with missing posterior teeth (1.5 ± 1.3 vs 0.6 ± 0.9) (P < .001), and bilateral location of missing posterior teeth (41 ± 39.0 vs 10 ± 9.5) (P < .001) were all significantly higher in patients with erosion than in those without erosion. The condylar erosion grade was significantly associated with the number of missing posterior teeth (odds ratio [OR] = 1.24; P = .006), the number of dental quadrants with missing posterior teeth (OR = 1.36; P = .006), and the bilateral occurrence of missing posterior teeth (OR = 3.03; P = .002).

CONCLUSION

The findings from this study suggest a possible association between TMJ condylar erosion grades and the number of missing posterior teeth, the number of quadrants with missing posterior teeth, and the bilateral occurrence of missing posterior teeth.

[A cone-beam CT investigation on condylar growth in beagle dog treated with Herbst appliance and prostaglandin E2 during late stage of growth]

Objective: To assess the mandibular condylar growth using cone-beam CT (CBCT) in beagle dogs treated with Herbst appliance and exogenous prostaglandin E2 (PGE2) during late stage of growth. Methods: Twenty-four male beagle dogs aged 8 months were divided into four groups according to the random number table (n=6 in each group): natural growth group, mandibular protraction group (Herbst group), injected prostaglandin E2 group (PGE2 group), mandibular protraction plus injected prostaglandin E2 group (Herbst+PGE2 group). The beagle dogs in Herbst+PGE2 group and PGE2 group were injected 0.1 ml of prostaglandin E2 (dose of 0.05 mg) into bilateral temporomandibular joint articular cavity. The dogs in natural growth group and Herbst group were injected 0.1 ml of saline into bilateral temporomandibular joint articular cavity as control. PGE2 and saline were injected once every 3 days for 60 days, respectively. CBCT was taken before the application of Herbst appliance and after removal of the appliance for all beagle dogs in four groups at the same time. The CBCT images were reconstructed using Invivo5 software and the relevant parameters of temporomandibular joint were measured. Results: No significant difference was found in natural growth group before and after the experiment (P>0.05). After the treatment, the condylar height and condylar size in Herbst group ([0.19+0.04] and [0.18+0.30] mm), PGE2 group ([0.38+0.14] and [0.51+0.24] mm) and Herbst+PGE2 group ([0.65+0.08] and [0.70+0.24] mm) slightly increased (P<0.05). The condylar changes in all experimental groups were greater than the natural growth group (P<0.05), and the ranges of change, in descending order, were Herbst+PGE2 group, PGE2 group and Herbst group (P<0.05). However, the condylar longitudinal distances, condyle width, condylar transverse diameter, glenoid fossa width and glenoid fossa depth had no statistically significant difference among the four groups (P>0.05). Conclusions: Injection of exogenous PGE2 into the temporomandibular joint articular cavity, or using Herbst appliance separately, a certain amount of growth was observed on the mandibular condyle in beagle dogs during late stage of growth. The combination of Herbst appliance and exogenous PGE2 injection made the condylar growth more obviously.

Three-dimensional positional assessment of glenoid fossae and mandibular condyles in patients with Class II subdivision malocclusion

OBJECTIVES

To test the null hypotheses that the positions of the glenoid fossae and mandibular condyles are identical on the Class I and Class II sides of patients with Class II subdivision malocclusion.

MATERIALS AND METHODS

Retrospective three-dimensional (3D) assessments of the positions of the glenoid fossae and mandibular condyles were made in patients with Class II malocclusion. Relative to a fiducial reference at the anterior cranial base, distances from the glenoid fossae and condyles were calculated in pretreatment cone beam computed tomographic scans of 82 patients: 41 with Class II and 41 with Class II subdivision malocclusions. The 3D distances from glenoid fossae to sella turcica in the X (right-left), Y (anterior-posterior), Z (inferior-superior) projections were calculated.

RESULTS

Patients with Class II malocclusion displayed a symmetric position of the glenoid fossae and condyles with no statistically significant differences between sides (P > .05), whereas patients with Class II subdivision showed asymmetry in the distance between the glenoid fossae and anterior cranial base or sella turcica (P < .05), with distally and laterally positioned glenoid fossae on the Class II side. (P < .05). Male patients had greater distances between glenoid fossae and anterior cranial fossae (P < .05). The condylar position relative to the glenoid fossae did not differ between the two malocclusion groups nor between males and females (P > .05).

CONCLUSIONS

The null hypotheses were rejected. Patients with Class II subdivision malocclusion displayed asymmetrically positioned right- and left-side glenoid fossae, with a distally and laterally positioned Class II side, although the condyles were symmetrically positioned within the glenoid fossae.

Accuracy of biomarkers obtained from cone beam computed tomography in assessing the internal trabecular structure of the mandibular condyle

OBJECTIVE

The aim of this study was to validate the ability of cone beam computed tomography (CBCT) to measure condylar internal trabecular bone structure and bone texture parameters accurately.

STUDY DESIGN

Sixteen resected condyles of individuals undergoing temporomandibular joint replacement were collected and used as samples. These condyles were then radiographically imaged by using clinically oriented dental CBCT and research oriented micro-computed tomography (micro-CT). The CBCT scans were then compared with the gold standard micro-CT scans in terms of 21 bone imaging parameters. Descriptive histologic investigation of the specimens was also performed.

RESULTS

Significant correlations were found for several imaging parameters between the CBCT and micro-CT images, including trabecular thickness (r = 0.92), trabecular separation (r = 0.78), bone volume (r = 0.90), bone surface area (r = 0.79), and degree of anisotropy measurements (r = 0.77).

CONCLUSIONS

Measurements of trabecular thickness, trabecular separation, bone volume, bone surface area, and degree of anisotropy obtained from high-resolution dental CBCT images may be suitable bone imaging biomarkers that can be utilized clinically and in future research.

Surgical treatment of condylar head fractures, the way to minimize the postraumatic TMJ ankylosis

Management of condylar head fractures (CHF) of the temporomandibular joint (TMJ) remains a source of controversy. Based on established literature, group of CHFs and conservative treatment connected with period of maxillomandibular fixation (MMF) increases the risk for TMJ ankylosis. This paper presents anatomical and functional results of surgical treatment of condylar head fractures in a group of 24 patients (29 joints). Fractures were diagnosed based on conventional radiographs and computed tomography (CT) scans. Utilising an intraoperative arthroscopy authors evaluated actual intraarticular posttraumatic changes. This study presents acceptable functional and radiological results of surgical treatment of condylar head fractures with more than 3-year follow-up. The authors believe that re-establishing the pretraumatic anatomic position of the TMJ components (fragment and the disc) and early postoperative rehabilitation are inevitable to minimize the risk of postraumatic TMJ ankylosis (Tab. 2, Fig. 8, Ref. 31).

Condylar surface CT value in sagittal plane before and after sagittal split ramus osteotomy

PURPOSE

The purpose of this study was to evaluate the relationship between computed tomography (CT) values of the condylar surface and temporomandibular joint (TMJ) disc position in the sagittal plane before and after sagittal split ramus osteotomy (SSRO) setback surgery, retrospectively.

MATERIALS AND METHODS

The subjects were 75 patients (150 condyles) who underwent bilateral SSRO setback surgery. They were divided into two groups (42 symmetric patients and 33 asymmetric patients). Maximum CT values (pixel values) of five points of the condylar surface and condylar height, length, fossa height, fossa length, and ramus angle in the sagittal plane were measured preoperatively and 1 year postoperatively. Disc position was classified as anterior disc displacement, anterior type, fully covered type, and posterior type, both pre- and postoperatively, using magnetic resonance imaging (MRI).

RESULTS

Postoperative value was significantly higher than preoperative one in CT value of 135° (P = 0.0199) and 180° (0.0363), in the non-deviation side in the asymmetry group. The anterior disc displacement group was significantly larger than those of some other areas pre- and postoperatively in the CT value of 0° point (P < 0.05).

CONCLUSIONS

This study suggested that CT value of the posterior site of the condylar surface could change in the non-deviation side in the asymmetry group after 1 year SSRO, and the condyle with anterior displacement showed high CT value at the anterior site of the condyle before and after surgery.

Cone-beam computed tomography evaluation on the condylar displacement following sagittal split ramus osteotomy in asymmetric setback patients: Comparison between conventional approach and surgery-first approach

OBJECTIVE

To compare the condylar displacement following sagittal split ramus osteotomy (SSRO) in asymmetric setback patients between the conventional approach and surgery-first approach and to determine whether the condylar displacement is affected by asymmetric setback in SSRO patients.

MATERIALS AND METHODS

This was a retrospective study. The subjects consisted of patients with facial asymmetry who underwent SSRO and had cone-beam computed tomography taken before and 1 month after surgery. They were allocated into the conventional (n = 18) and surgery-first (SF) groups (n = 20). Descriptive, independent t-tests and Pearson correlation analysis were computed.

RESULTS

The amount of condylar displacement in x-, y-, and z-directions and Euclidean distance showed no statistically significant differences between the conventional and SF groups. Comparing the postoperative condylar position with the preoperative position, the condylar displacement occurred in posterior (P < .05) and downward (P < .05) directions in both groups except on the deviated side in the conventional group. The condylar displacement occurred in a posterior (P < .05) direction on the deviated side of the conventional group. However, the condylar displacement in three dimensions showed no statistically significant differences between the two groups. In the correlation analysis, the condylar displacement in both the deviated and contralateral sides showed no significant correlation with asymmetric setback in either group.

CONCLUSION

The condylar displacement in three dimensions and the distance of condylar displacement in SSRO patients with facial asymmetry showed no significant difference between conventional and SF groups. Condylar displacement was not associated with asymmetric setback.

[MRI analysis of the effect on mandibular retrusion with anterior disc displacement treated by using Herbst appliance]

Objective: To investgate the effect of Herbst appliance on the growth and remodeling of the temporomandibular joint (TMJ) in class Ⅱ patients with mandibular retrusion by using MRI. Methods: Between December 2010 and October 2014, 12 class Ⅱ patients (11-16 years old) with mandibular retrusion were chosen. The patients were divided into two groups. The control group included 7 patients (14 joints) with normal disc condyle relationship and the anterior disc displacement (ADD) group included 5 patients (10 joints) with anterior disc displacement. The MRI images of TMJ were measured, including condylar height, joint space index and disc position ratio, before and after the treatment. Results: The condylar height of the patients in the control group was significantly increased (P<0.001) after treatment, and no significant difference in joint space index (P=0.821) and disc position ratio (P=0.146) was found. The joint space index of the patients ([-14.70±8.82]% and [4.90±11.35]%) in ADD group changed significantly (P<0.001) after treatment, and no significant difference in condylar height (P=0.294) and disc position ratio (P=0.120) was found. Conclusions: The normal disc condyle relationship was beneficial to the reconstruction of the condylar process, and the increase of the condylar height. The condyle moved forward in patients with anterior disc displacement after treatment.

Symmetry of elements of temporomandibular joint (TMJ)

OBJECTIVE

Introduction: Dysfunction of temporomandibular joint is present in 70-75% of orthodontic patients. Evaluation of TMJ and detailed characteristics of its elements with additional methods of examination in children and adults is necessary for clinical definition of proposed disturbances of the structure and functions of the joint. The aim of the investigation is to study morphological symmetry of TMJ in patients with dentofacial abnormalities and with dentofacial abnormalities complicated by secondary edentulism.

PATIENTS AND METHODS

Materials and Methods: 57 patients were involved in the examination. Based on gender principle patients' distribution was almost equal: there were 30 women and 27 men. Cone-beam computerized tomography (CBCT) Galileos (SIRONA DENTAL, Germany) was used to all patients.

RESULTS

Results: It was done analysis of parameters (height and length) of right and left heads (condyles) of temporomandibular joint in both groups. Asymmetry of parameters of heads' length in saggital area in patients of the second group was defined. It was proved statistically (left 10,38±0,76, right 8,16±0,78).

CONCLUSION

Conclusions: Increase of asymmetry of length of heads of TMJ in saggital area with age was determined. It can be explained by complication of dentofacial abnormalities and the presence of secondary edentulism. Depending on bite type length of condyle, especially at prognathism (in saggital) area peculiar clinical problems with TMJ can be present due to asymmetry of condyles. The size of joint gaps of TMJ due to the presence of dentofacial abnormalities with age demonstrates compensatory ability and saves its.

Effect of Increasing Low-Intensity Pulsed Ultrasound and a Functional Appliance on the Mandibular Condyle in Growing Rats

OBJECTIVES

Functional appliances are used for treatment of lower-jaw deficiencies in growing individuals; however, their effectiveness is debatable. Low-intensity pulsed ultrasound (US) is a noninvasive method, which has been shown to stimulate cartilage and bone formation with 20 minutes of application. This study was designed to test the hypothesis that increasing low-intensity pulsed US application from 20 to 40 min/d will enhance mandibular condylar growth in growing rats, especially when combined with a functional appliance.

METHODS

Fifty-four Sprague Dawley rats were divided into 6 groups (n = 9): control, low-intensity pulsed US for 20 minutes, low-intensity pulsed US for 40 minutes, the functional appliance, the functional appliance plus low-intensity pulsed US for 20 minutes, and the functional appliance plus low-intensity pulsed US for 40 minutes. Low-intensity pulsed US was applied for 28 days. All rats were then euthanized, and their mandibles were dissected for morphometric, histomorphometric, and micro-computed tomographic analyses.

RESULTS

Among all study groups, the 20-minute US group showed significant increases in most of the measured variables (P < .05) except for condylar process length (P = .18), whereas the functional appliance-plus-40-min US group showed the least favorable results. The 20-minute US group showed increases in proliferative and hypertrophic cell counts and widths and enhanced microarchitecture of trabecular bone compared with the 40-minute US group. The functional appliance-plus-20-minute US group showed better results compared with the functional appliance-alone and functional appliance-plus-40-minute US groups.

CONCLUSIONS

A daily application of low-intensity pulsed US for 20 minutes in growing rats affects mandibular growth, either alone or in combination with a functional appliance. Further study with a longer observation period is required to study the long-term effects and stability of newly formed bone.

Evaluation of temporomandibular fossa and mandibular condyle in adolescent patients affected by bilateral cleft lip and palate using cone beam computed tomography

The purposes of this study were to investigate the position of the mandibular condyle and temporomandibular fossa between the adolescent patients affected by bilateral cleft lip and palate (BCLP) and well-matched controls without any cleft by using cone-beam computed tomography (CBCT). The study sample consisted of 17 patients (7 females and 10 males; mean age, 14.27 ± 2.83 years) affected by BCLP and 17 patients (6 females and 11 males; mean age, 14.27 ± 2.12 years) as age-and sex-matched control group without any cleft. Using cone-beam computed tomography segmented three-dimensional temporomandibular fossa and mandibular condyle images were reconstructed and angular, linear, and volumetric measurements of the patients in both sides of the groups were examined using Paired and Student's t-tests. Comparison of the sides showed that both sides were found to be similar in BCLP and control groups, except the condylar angulation of the right side was found to be higher compared to that of the left side in both groups (p < 0.05). Comparison of the groups showed that the patients affected by BCLP and non-cleft patients had similar values for all parameters, except for the condylar angulation in the right side (BCLP group had less angulation compared to controls; p < 0.05). The condylar volume was found to be slightly less in the BCLP group in both sides compared to the controls (p > 0.05). The positions of the mandibular condyle and temporomandibular fossa were found to be similar in patients affected by BCLP and control group of without any cleft. SCANNING 38:720-726, 2016. © 2016 Wiley Periodicals, Inc.

Cellular and Matrix Response of the Mandibular Condylar Cartilage to Botulinum Toxin

OBJECTIVES

To evaluate the cellular and matrix effects of botulinum toxin type A (Botox) on mandibular condylar cartilage (MCC) and subchondral bone.

MATERIALS AND METHODS

Botox (0.3 unit) was injected into the right masseter of 5-week-old transgenic mice (Col10a1-RFPcherry) at day 1. Left side masseter was used as intra-animal control. The following bone labels were intraperitoneally injected: calcein at day 7, alizarin red at day 14 and calcein at day 21. In addition, EdU was injected 48 and 24 hours before sacrifice. Mice were sacrificed 30 days after Botox injection. Experimental and control side mandibles were dissected and examined by x-ray imaging and micro-CT. Subsequently, MCC along with the subchondral bone was sectioned and stained with tartrate resistant acid phosphatase (TRAP), EdU, TUNEL, alkaline phosphatase, toluidine blue and safranin O. In addition, we performed immunohistochemistry for pSMAD and VEGF.

RESULTS

Bone volume fraction, tissue density and trabecular thickness were significantly decreased on the right side of the subchondral bone and mineralized cartilage (Botox was injected) when compared to the left side. There was no significant difference in the mandibular length and condylar head length; however, the condylar width was significantly decreased after Botox injection. Our histology showed decreased numbers of Col10a1 expressing cells, decreased cell proliferation and increased cell apoptosis in the subchondral bone and mandibular condylar cartilage, decreased TRAP activity and mineralization of Botox injected side cartilage and subchondral bone. Furthermore, we observed reduced proteoglycan and glycosaminoglycan distribution and decreased expression of pSMAD 1/5/8 and VEGF in the MCC of the Botox injected side in comparison to control side.

CONCLUSION

Injection of Botox in masseter muscle leads to decreased mineralization and matrix deposition, reduced chondrocyte proliferation and differentiation and increased cell apoptosis in the MCC and subchondral bone.

Sequential changes of postoperative condylar position in patients with facial asymmetry

OBJECTIVE

To evaluate sequential images of the condylar position in relation to the glenoid fossa after orthognathic surgery in patients with facial asymmetry using cone beam computed tomography.

MATERIALS AND METHODS

A total of 20 adult patients (11 men and 9 women; mean age, 22.1 ± 4.02 years) with facial asymmetry who underwent sagittal split ramus osteotomy with rigid fixation were involved. Cone beam computed tomography scans were obtained before treatment (T0), 1 month before the surgery (T1), and 1 day (T2), 3 months (T3), 6 months (T4), and 12 months (T5) after the surgery. The condyle position was evaluated.

RESULTS

At 1 day after surgery (T2), the condylar position on both sides significantly changed posteriorly, inferiorly, and laterally, but no significant difference was observed between the nonaffected and affected sides. The condyle on the nonaffected side had a tendency to recover its preoperative position at 3 months after surgery (T3) and inclined slightly laterally up to 1 year after the surgery (T5). The condyle on the affected side returned more closely to the glenoid fossa than to its pretreatment position at 3 months after surgery (T3). Thereafter, it showed a more backward and downward position (T5).

CONCLUSIONS

The overall condylar position after an orthognathic surgery in patients with facial asymmetry was relatively stable at 1 year after surgery. However, the condyle on the affected side during the first 3 months after surgery should be carefully monitored for surgical stability.

Single Photon Emission Computed Tomography without and with Hybrid Computed Tomography in Mandibular Condylar Hyperplasia

OBJECTIVE

Bone scintigraphy (BS) has been the mainstay in evaluating patients with mandibular condylar hyperplasia (CH). Both planar BS and single photon emission computed tomography (SPECT) have been used to determine cessation of condylar hyperactivity before corrective surgery. The present study aimed to examine the utility of the relatively new single photon emission computed tomography/computed tomography (SPECT/CT) technique for evaluation of CH.

MATERIAL AND METHOD

Sixty-one mandibular Tc-99m methylene diphosphonate bone SPECT/CT studies were reviewed. Images were analyzed without and with fusion with anatomical CT. Condylar uptake were quantified and differences in uptake between the right and left condyles were determined by both maximum uptake and average uptake in the region of interes (ROI). Differences exceeding 10 percentage points indicated condylar hyperactivity.

RESULTS

SPECT and SPECT/CT showed positivity in 34 and 31 examinations, respectively. Agreement between the two modalities was high, but was not perfect. SPECT was found to be more reproducible than SPECT/CT. Quantification using maximum ROI counts was more reproducible than using average ROI counts.

CONCLUSION

No evidence was found to indicate superiority of SPECT/CT over simple SPECT for evaluation of condylar hyperactivity in CH, as demonstrated by the lower intra-modality reproducibility and a trend towards lower sensitivity for detection of hyperactive condyles. Utilization of SPECT alone would further benefit in terms of reduction of patient radiation exposure which is a concern, especially in younger patients such as those with CH. When using quantification, maximum ROI counts should be used over average ROI counts.

Growth hormone receptor gene variant and three-dimensional mandibular morphology

OBJECTIVE

To examine the relationship between three-dimensional mandibular morphology and growth hormone receptor (GHR) gene variants in a healthy Japanese population.

MATERIALS AND METHODS

The subjects, who were unrelated Japanese orthodontic patients, consisted of 64 men and 114 women. Using the Taqman genotyping assay, GHR gene rs6184 and rs6180 variants were detected in genomic DNA extracted from saliva. Mandibular volume and length were measured from cone-beam computed tomography images that were analyzed using Analyze image-processing software. The relationship between GHR gene variants and three-dimensional mandibular morphology was statistically examined.

RESULTS

Statistical significance for the relationship between the distance between the left and right coronoid processes and rs6180 was noted (P < .05).

CONCLUSION

Our results indicate that the GHR variant rs6180 is associated with the distance between the left and right coronoid process in the Japanese subjects.

The Relationship Between Retruded Contact Position and Intercuspal Position in Patients with TMJ Osteoarthritis

This study was conducted to investigate the relationship between posterior mandibular excursion movement and temporomandibular joint osteoarthntis (TMJ OA) in 25 orthodontic patients with Angle Class I and Class II, using a six degrees-of-freedom measuring device and helical computed tomography. There were significant differences found in three-dimensional length, antero-posterior, absolute latero-medial and supero-inferior incisal, and condylar intercuspal position (IP)-retruded contact position (RCP) slides between bilateral, unilateral, and no condylar bone change groups. With respect to the types of condylar bone change, there were significant differences found in three-dimensional length, antero-postenor, and absolute latero-medial condylar IP-RCP slides between flattening, erosion and osteophyte groups. These results suggest that large three-dimensional, not only incisal but also condylar, IP-RCP slides might be related to the uni-/bilaterality and kind of TMJ pathosis, which might make such slides useful as clinical indices of TMJ OA.

Comparison of cone-beam computed tomography with multislice computed tomography in detection of small osseous condylar defects

INTRODUCTION

Previous studies have indicated that orthodontic-grade cone-beam computed tomography (CBCT) images are limited when displaying small defects at the mandibular condyles for diagnosis. In this study, we investigated whether this limitation was inherent to CBCT by comparing CBCT with multislice computed tomography (CT), and whether image segmentation and color mapping could overcome this limitation.

METHODS

Nine fresh pig heads (18 condyles, 36 medial and lateral condylar regions) were used. Small osseous defects (diameter and depth, 1.5 mm) were created at the medial and lateral regions of the condyles shown by gutta percha markers. After the overlying soft tissues were restored, the pig heads underwent orthodontic-grade CBCT scans (0.4-mm voxel size; i-CAT; Imaging Sciences International, Hatfield, Pa) and medical-grade CT scans (0.625-mm voxel size; LightSpeed; GE, Little Chalfont, Buckinghamshire, United Kingdom). Subsequently, 2 calibrated and blinded raters diagnosed the defect numbers in each condylar region from CBCT and CT images using Dolphin 3D software (Patterson Supply, St Paul, Minn) without image segmentation, and then 1 week later with the proprietary image segmentation and color mapping tools of Dolphin 3D. Condylar polyvinyl siloxane impressions were collected and evaluated by the same raters to obtain physical diagnoses. Rediagnoses were made on randomly selected subsamples to assess reliability. Using the physical diagnoses as references, the accuracy of imaging diagnosis was assessed and statistically compared among the varied imaging and analysis methods.

RESULTS

Image diagnoses of all imaging and analysis methods showed good or excellent intrarater and interrater reliability values, except for those of the segmented CBCT images, which were substantially lower. The numbers of overdiagnoses and underdiagnoses per condylar region were not significantly different among the varied imaging and analysis methods (Wilcoxon tests, P >0.05), but classification functions demonstrated substantially lower sensitivity and accuracy with CBCT than with CT. Logistic regression also showed that CT had a significantly higher probability (odds ratio, 2.4) than CBCT in reaching the correct diagnosis, whereas use of the image segmentation and color mapping tool proprietary to Dolphin 3D did not improve the diagnostic accuracy from CBCT images.

CONCLUSIONS

Even at a lower voxel size than medical CT images, orthodontic-grade CBCT images of mandibular condyles may be inherently less reliable and less accurate for the diagnosis of small condylar defects.

[A cone-beam CT investigation on the effect of two-phase treatment and fixed appliance treatment only on temporomandibular joint]

OBJECTIVE

To assess the effects of two phase treatment(Herbst and fixed appliance) and fixed appliance treatment only(edgewise appliance) on temporomandibular joint in Cass Ⅱ patients with mandibular retrusion using cone-beam CT(CBCT) analysis.

METHODS

Thirty Class Ⅱ patients with mandibular retrusion in the permanent dentition were divided into two groups. Group A consisted of 15 patients with two phase treatment. Group B consisted of 15 patients with fixed appliance treatment only. CBCT was taken before(T1) and after(T2) treatment. The Invivo Dental software was used to calculate the relevant parameters of temporomandibular joint. Wilcoxon analysis was carried out.

RESULTS

In group A, the condylar anterior-posterior diameters(7.41[2.55]) and the condylar head height(3.58[0.86]) increased significantly after treatment(P<0.05). In group B, all skeletal measurements had no significant changes(P> 0.05) after treatment. The changes of condylar head height in group A(0.60[0.48]) showed greater than in group B(0.02[0.21]) (P<0.05). No significant differences in the temporomandibular joint spaces were found before and after treatment, and between the two groups(P>0.05).

CONCLUSIONS

Compared with fixed appliance treatment only, except for condylar growth changes, no significant changes of other skeletal morphology of the temporomandibular joint and the condyle position within the glenoid fossa were found between patients with two phase treatment and with fixed appliance treatment only.

Are condylar morphologic changes associated with temporomandibular disorders in patients with orthognathia?

OBJECTIVE

To determine the association between morphologic condylar changes and temporomandibular disorders (TMDs) in patients with orthognathia.

STUDY DESIGN

Data from 89 patients were analyzed. TMDs were classified according to the Research Diagnostic Criteria for TMDs. TMD severity was scored according to the Helkimo indices. Calculation of the condylar area, perimeter, and height was performed by using a specific computational method including panoramic radiography.

RESULTS

Sixty-five (73%) patients presented with morphologic condylar changes. Decreases in condylar perimeter and area were found to be predictors of postoperative TMDs (P = .009; odds ratio [OR] = 3.66) and disk displacement (P = .008; OR = 4.43), respectively. Condylar area and height decreases were associated with worsening of TMDs (P = .03 and 0.04).

CONCLUSIONS

This study demonstrated that in orthognathic patients, postoperative condylar changes are associated with postoperative TMDs as well as with the degree of TMD severity and that preoperative TMDs are associated with such condylar changes.

Quantitation of condylar position in temporomandibular joint. A methodological study

Ten CBCT scans of asymptomatic patients were evaluated on sagittal slices to obtain condylar position in temporomandibular joint. Measurements focused on antero-posterior and superior-inferior position of the condyle. The study the study was performed to investigate reproducibility of the method described before using Dahlberg formula. The method seems to be fair reproducible.

Type and location of findings in dental panoramic tomographs in 7-12-year-old orthodontic patients

OBJECTIVE

The Radiation and Nuclear Safety Authority in Finland has paid attention to the large numbers of dental panoramic tomographs (DPTs), particularly in 7-12-year-old children. The majority of these radiographs are taken for orthodontic reasons. Because of the high radiosensitivity of children, the size of the irradiated field should be carefully chosen to yield the necessary diagnostic information at the lowest possible dose. The purpose of the present study was, therefore, to assess the outcome of DPTs within this age group in terms of type and location of pathological findings. It was also hypothesized that DPTs of orthodontic patients rarely display unrestored caries.

MATERIALS AND METHODS

Four hundred and forty-one DPTs, taken of 7-12-year-old children in 2010-2014, were randomly sampled. The 413 of them (94%) that had been taken for orthodontic reasons were analysed.

RESULTS

All pathologic findings were restricted to the tooth-bearing area and there was no pathology in the bone structure or any incidental findings in the region of temporomandibular joint. Unlike hypothesized, 27% of the orthodontic DPTs showed caries in deciduous teeth and 16% in permanent teeth. A sub-sample of 229 DPTs, analysed for developmental dental and occlusal problems, most commonly displayed crowding (50%), positional anomalies and local problems with tooth eruption (32%), as well as hyperodontia (15%).

CONCLUSION

Inclusion of only the actual area of interest in the image field should be considered case-specifically as a means to reduce the radiation dose.

Case Report: An Unusual Finding of a Solitary Bone Cyst in a Patient with a Fractured Mandible

Solitary bone cysts are uncommon. They have a reported incidence of 0.6% and are commonest in the mandible. The case of a 16-year-old patient who attended Accident and Emergency with a fractured mandible and the incidental finding of a solitary bone cyst is presented. Solitary bone cysts are usually asymptomatic and generally heal fully following surgical exploration. CPD/Clinical Relevance: This case report aims to increase awareness of the general dental practitioner of solitary bone cysts as a possible finding in patients with pathological jaw fractures and radiolucencies of the jaws. It outlines the surgical management that is carried out on patients with solitary bone cysts.

An anatomic study of the attachments on the condylar process of the mandible: muscle bundles from the temporalis

PURPOSE

The aim of this study was to evaluate anatomically the relationship between bone and muscles by detailed observation of the bone shape and the structure of muscles to facilitate an understanding of the function of the muscles involved in jaw movement.

METHODS

36 specimens of 24 Japanese cadavers were examined. The insertion areas were marked using a radiopaque marker and examined by micro-computed tomography. For morphological observation, we used 101 condylar processes. In addition, we made histological sections in some specimens to observe the detailed attachments of the muscle.

RESULTS

Based on the micro-CT images and dissection findings, the lateral pterygoid muscle was found to be most frequently inserted into the anterior impression and attached to the medial impression of the process. According to the histological observations, the lateral pterygoid muscle mainly inserted to the condylar process. The micro-CT images indicated that the obvious bony ridge was lateral to the pterygoid fovea on the condylar process in all specimens. The midmedial muscle bundle of the temporalis was attached to the ridge. Based on the morphological observations, the ridge was situated on the lateral area of the condylar process.

CONCLUSIONS

Since dysfunction of the temporomandibular joint is likely closely related to both the lateral pterygoid muscle and also the temporalis, further studies are necessary to evaluate the function of these muscles and consider jaw movement.

Detection of mandibular condyle pesudocysts in panoramic radiographs: Digital and film-based radiology

OBJECTIVE

To determine the detection rate of mandibular condyle pseudocyst in both digital panoramic radiographs and film-based panoramic radiographs.

METHOD AND MATERIALS

All film-based and digital panoramic radiographs of patients treated at our institute during a 4-month period were analyzed by two experienced practitioners. Diagnosis of a condylar pseudocyst was based on the following criteria: appearance of cyst-like radiolucency, partially or completely circumscribed by radiopaque border, located at the anterior aspect of mandibular condyle.

RESULTS

825 radiographs (415 film-based, 410 digital) were included in the study. In 342 (41.5%) radiographs at least one condylar pseudocyst was observed, with no differences between radiograph type, 173 (42.2%) in digital and 169 (40.7%) in film-based radiographs (P = .36). Condylar pseudocyst detection rate was positively associated with older age (P < .001), whereas gender had no influence (P = .93).

CONCLUSION

An equally high detection rate of condylar pseudocyst was found in digital and film-based panoramic radiographs.

Limited mouth opening of unknown cause cured by diagnostic coronoidectomy: a new clinical entity?

Limited mouth opening is a constant annoyance and can be life-threatening should intubation be needed. The causes are numerous and are categorised as intra-articular or extra-articular, which are often difficult to distinguish. We present what we regard as a new clinical entity - long-standing limited mouth opening of unknown cause - and describe our treatment. Four female patients presented with limited mouth opening and lateral and protrusive movements within normal limits, which were typical of restriction of extra-articular origin. However, the radiological findings were within normal limits, with no visible cause of the restriction. All four were treated by bilateral coronoidectomy that resulted in the immediate return of mouth opening to within normal limits that was preserved over subsequent years. Histopathological examination showed atrophy and degenerative changes in the temporalis band that had been attached to the coronoid, which accounts for the stiffness of the temporalis muscle but does not explain the pathogenesis. In the light of this "diagnostic coronoidectomy" further studies are required to document the underlying pathological changes and to develop more accurate imaging that will enable correct diagnosis in future.

Three-dimensional quantitative analysis of the bone density of mandibular condyle in dentulous and edentulous jaws: an in vivo study

Studies have reported that masticatory function and occlusal force are low in edentulous patients, which brings about a change in the density, thickness, and alignment of bony trabeculae. However, studies that have quantitatively measured the differential cortical and medullary bone densities of the mandibular condyle in vivo remain rare. This study determined and compared the cortical and medullary bone density of the mandibular condyle in dentulous and edentulous jaws, using multidetector computed tomography (CT). Forty mandibular condyles with no clinical signs of temporomandibular disorders were investigated in 2 groups with 10 subjects (aged 50-80 yr) in each group (group I: dentulous subjects with maintained occlusion; group II: completely edentulous patients) with multidetector CT. The density of condylar cortical and medullary bone was determined by using bone density analysis algorithms available within the proprietary software. Data were analyzed statistically with the 1-way analysis of variance test (p<0.05). The mean cortical bone density of the right and left condyles of group I was 686.11±102.78 Hounsfield unit (HU) and 775.91±89.62 HU, respectively and that of group II was 531.33±289.73 HU and 648.53±294.39 HU, respectively. The mean medullary bone density of the right and left condyles was maximum in group I subjects (429.69±102.62 HU and 486.62±108.60 HU, respectively) than in group II subjects (214.89±104.37 HU and 205.36±90.91 HU, respectively) with a statistically significant decrease in the mean scores (p<0.001). Within the limitations of this study, it can be concluded that the cortical and medullary densities of the mandibular condyle are more in dentulous than the edentulous jaws.

On the analysis of condylar path versus real motion of the temporomandibular joint: application for Sicat Function

Analysis of temporomandibular joint (TMJ) function using condylar path tracings is a challenge in functionally oriented dentistry. In most cases, reference points on the skin surface over the TMJ region are defined as "arbitrary", "individual" or "kinematic" condylar hinge axis points, which are displayed as "condylar paths" in motion. To what extent these reference points represent the actual condylar paths in each individual patient is ultimately unclear because the geometric relationship of the actual condyle to the selected reference point is usually unknown. Depending on the location of the point on the condyle and the centers of rotation of mandibular movement, these trajectories can vary greatly during combined rotational and sliding movements (eg, opening and closing movements of the mandible); this represents a grid of points located in the vicinity of the TMJ. To record the actual condylar path as the movement trajectory of a given point (eg, the condylar center), technological solutions are needed with which to link the tracing technology with the appropriate imaging technology capable of scanning the condyle, including the points of interest, and displaying them in real dynamic motion. Sicat Function (Sicat, D-Bonn) is such a solution. Sicat Function links cone beam computed tomography (CBCT) scans (made using the Galileos CBCT scanner; Sirona, Bensheim, Germany) with ultrasound-based, three-dimensional (3D) functional jaw movement recordings of the mandible (made using the JMT+ Jaw Motion Tracker; Sicat, Bonn, Germany). Digital images of the dental arches acquired with the intraoral scanner Cerec system (Sirona) can also be superimposed. This results in the generation of a 3D model of the bony mandible, including the TMJ, which reproduces the 3D real dynamic movement of the condyles simultaneously with that of the condylar paths at defined points (with the condylar centers being a particular point of interest). Sicat Function is an integrated, digital 3D solution for additional instrumental and imaging diagnosis of temporomandibular joint dysfunction (TMD). The primary indication for Sicat Function is persistent, arthrogenic TMD complaints that require additional studies for evaluation of bony structural components of the TMJ.

A three-dimensional morphometric study on the position of temporomandibular joints

OBJECTIVES

To address the controversy, in which indications average value articulation is suitable or to what extent individual registrations, especially using the facebow, should be applied, a quantification of the variability of relevant anatomical landmarks is necessary. The goal of this study was to investigate the mean and natural bandwidth of the parameters describing articulation.

METHODS

Significant landmarks were measured on three-dimensional (3D) cone beam computed tomography (CBCT) scans of 120 arbitrarily selected individuals. The bandwidth and mean values of the anatomical relations were calculated.

RESULTS

The mean arm length of the Bonwill triangle was 103.3 mm, with a range of 90.2 mm (minimum) to 117.9 mm (maximum), and a mean base length of 99.6 mm, with a range of 85.2 mm to 112.6 mm. There was a high correlation between the length of the left and right arms, but not between the arms and the base. The mean height of the Bonwill triangle, measured between the condyles and the occlusal plane, resulted in 34.3 mm, with a range of 21.0 mm to 47.2 mm. The mean value of the Balkwill angle was 20.4 degrees, with a range of 9.0 degrees to 27.6 degrees. The angle between the Camper's line and the occlusal plane averaged around 7 degrees.

CONCLUSIONS

This study presents the bandwidth of anatomical relations necessary for articulation systems. The results are specific for males and females. The relevant parameters offer a high symmetry between the right and left sides. Additionally, the results show that the Bonwill triangle is more likely to be isosceles than equilateral.

CLINICAL SIGNIFICANCE

The knowledge of the anatomical bandwidth of temporomandibular joint (TMJ) positions in relation to the dentition allows the simulation of software- controlled virtual articulators and the substitution of facebows.

Treatment of an extensive unicystic ameloblastoma in a 7-year-old child: the best approach?

Ameloblastoma is a benign, slow-growing neoplasm of the jaw that arises from odontogenic epithelium. We present the case of a 7-year-old girl with a unicystic ameloblastoma of the mandible, and describe our approach to treatment.

Bony deviations revealed by cone beam computed tomography of the temporomandibular joint in subjects without ongoing pain

AIMS

To assess the prevalence of temporomandibular joint (TMJ) bony changes in cone beam computed tomography (CBCT) images of adult subjects without ongoing orofacial pain or complaints from the TMJ.

METHODS

The study included 84 TMJs from 28 men and 14 women (mean age [± SD]: 51 ± 11 years) without orofacial pain or TMJ complaints who were participants in a study of patients with obstructive sleep apnea. They were examined before any treatment with the Research Diagnostic Criteria for Temporomandibular Disorders and with CBCT (NewTom VGi; 15 × 15 cm, exposure time 18 seconds, axial thickness 0.3 mm). Osseous TMJ deviations were assessed blindly and classified.

RESULTS

Degenerative changes were noted in the CBCT images of 33 (39.3%) of the TMJs, of which 21 were classified as osteoarthritic alterations and 12 as indeterminate changes of osteoarthritis. Two TMJs were clinically classified as osteoarthrosis and 6 as disc displacement with reduction. The CBCT images of the 2 TMJs with a clinical diagnosis of osteoarthrosis showed also bony changes, but the CBCT images also revealed osteoarthritic bony changes in the 18 TMJs without any clinical diagnosis.

CONCLUSION

CBCT images of asymptomatic adult TMJs commonly show degenerative bony alterations. Accordingly, such radiographic findings should be used with care and only as a supplement to clinical assessment.

Ectopic presence of tooth within the mandibular condyle

This article describes the case of a 41-year-old woman who presented with the complaint of crepitation sound and mild pain in the left temporomandibular joint area. Panoramic radiographs taken to rule out degenerative or arthritic changes in the joints demonstrated a radiopaque mass within the left condyle. Cone beam computed tomography scans revealed an ectopic tooth located centrally within the left condyle. Thus, while considered rare, the mandibular condyle can be a possible location of an ectopic tooth.

Antioxidant capacity of synovial fluid in the temporomandibular joint correlated with radiological morphology of temporomandibular disorders

We investigated the correlation between the antioxidant capacity of synovial fluid and radiological findings of intra-articular structures in patients with disorders of the temporomandibular joint (TMJ). We recruited 21 patients (9 men and 12 women, aged 18-84 years of age) with such disorders, excluding myofascial pain and dysfunction syndrome, or other muscular disorders. The clinical variables recorded included age, sex, interincisal distance, and visual analogue pain scores (VAS). Radiological findings were obtained from diagnostic arthrogram and cone-beam computed tomography (CT). The antioxidant capacity of the synovial fluid was measured by chemiluminescence. Eleven patients were radiologically diagnosed with closed lock, and the remaining 10 with no closed lock. An anchored intra-articular disc was most often seen on cone-beam CT (n=19) followed by perforated disc (n=7), osteoarthrosis (n=7), and anterior disc displacement without reduction (n=5). Although there were no significant differences between antioxidant capacity and age, sex, VAS, or any findings on cone-beam CT, antioxidant capacity was significantly decreased in the patients with closed lock compared with those who did not have closed lock (p=0.02). The results suggest an association between the oxidative stress of the synovial fluid and closed-lock in disorders of the TMJ.

Intrauterine temporomandibular joint dislocation: prenatal sonographic evaluation

Congenital temporomandibular joint (TMJ) diseases are very rare disorders and are usually diagnosed in childhood. Developmental disorders of the TMJ such as hypoplasia, hyperplasia, and aplasia of the TMJ compartments are characterized by TMJ dysfunction. In childhood, these patients experience recurrent dislocation, pain, and malocclusion. We present the case of a 25-week fetus with unilateral TMJ dislocation with fluid retention in the joint diagnosed by ultrasonography. To the best of our knowledge, this is the first case of TMJ dislocation diagnosed by ultrasonographic evaluation during the prenatal period.

[A cone-beam CT study on morphology and position of condylar processes in skeletal Class III adult patients with mandibular deviation]

OBJECTIVE

To evaluate the morphology and position of condylar processes in skeletal Class III adult patients with mandibular deviation.

METHODS

Twenty skeletal Class III adult patients with mandibular deviation were selected as the deviated group and twenty adults with normal occlusion were selected as the control group. Cone- beam CT (CBCT) scans of their temporomandibular joints were taken. The original data were reconstructed and rebuilt. A series of measurements of the condylar morphology and location were performed. The collected data were analyzed using paired t- test.

RESULTS

In the deviated group, the deviated sides were smaller than the contralateral sides in the perpendicular height, volume, maximum area of axial plane and the height of condylar head. The contralateral condyle was positioned more posteriorly and laterally [(0.35 ± 0.10) and (0.58 ± 0.18) mm] than the deviated condyle (P < 0.05).

CONCLUSIONS

Adult skeletal Class III patients with mandibular deviation had some extent of condyle asymmetry in both morphology and location.

Early intra-articular injection of alendronate reduces cartilage changes and subchondral bone loss in rat temporomandibular joints after ovariectomy

This study investigated the effects of intra-articular injection of alendronate on the mandibular condyle in ovariectomized rats. Sixty rats were divided into five groups: ovariectomy with vehicle treatment alone, early alendronate treatment at ovariectomy, late alendronate treatment at 4 weeks after ovariectomy, sham-operation with vehicle treatment, and normal controls. The changes in cartilage and subchondral bone were evaluated by micro-computed tomography, histology, tartrate-resistant acid phosphatase (TRAP) staining, immunohistochemistry, and real-time quantitative polymerase chain reaction. Compared with late alendronate treatment, early alendronate treatment completely inhibited cartilage thickening (727.6±39.3 vs. 1013.3±51.6; P=0.017) and improved microstructural properties of the subchondral bone, with a higher bone volume ratio (46.4±2.5 vs. 37.5±2.1; P=0.038), trabecular thickness (47.3±1.7 vs. 34.6±1.4; P=0.029), and trabecular number (8.5±0.6 vs. 6.2±0.3; P=0.041) and lower trabecular separation (30.2±1.6 vs. 37.7±2.6; P=0.034). Fewer TRAP-positive cells (4.2±0.2 vs. 6.8±0.4; P=0.019) and a higher OPG/RANKL ratio (0.38±0.01 vs. 0.25±0.03; P=0.043) in the subchondral bone were observed in the animals with early treatment compared to late treatment or ovariectomy/vehicle treatment. In addition, early alendronate treatment blocked the up-regulation of matrix metalloproteinase (MMP)-13 expression in the chondrocytes, whereas late alendronate treatment attenuated the up-regulation of MMP-13 expression. Our results suggest the therapeutic potential of intra-articular alendronate injection in the treatment of osteoporosis-associated temporomandibular disorders.