Automated Real-Time Evaluation of Condylar Movement in Relation to Three-Dimensional Craniofacial and Temporomandibular Morphometry in Patients with Facial Asymmetry

The aim of this study was to investigate the correlation between craniofacial morphology, temporomandibular joint (TMJ) characteristics, and condylar functional movement in patients with facial asymmetry using an up-to-date automated real-time jaw-tracking system. A total of 30 patients with mandibular asymmetry and prognathism were included. Three-dimensional (3D) craniofacial and TMJ morphometric variables were analyzed in images captured using cone-beam computed tomography. Three-dimensional condylar movements were recorded during the opening, protrusion, and laterotrusion of the jaw and divided into those for deviated and non-deviated sides. Overall functional and morphometric variables were compared between the sides by a paired t-test. Pearson’s correlation analysis and factor analysis were also performed. As a result, significant differences were found between the sides in morphometric and functional variables. The condylar path length was significantly longer and steeper on the deviated side during protrusion and lateral excursion. TMJ morphometric asymmetry, more so than the craniofacial morphologic asymmetry, seemed to be reflected in the functional asymmetry, representing different correlations between the sides, as supported by factor analysis. This study provides evidence explaining why the asymmetric condylar path remained unchanged even after orthognathic surgery for the correction of craniofacial asymmetry.

Evaluating the morphological features of the lateral pterygoid insertion into the medial surface of the condylar process

OBJECTIVE

The lateral pterygoid is vital in coordinating multidimensional jaw movements. Since a vector in three-dimensional (3D) space is defined by two 3D points, the role of the lateral pterygoid in 3D jaw movements is defined by its origin and insertion. Reportedly, the lateral pterygoid is inserted into not only the pterygoid fovea but also into the medial surface of the condylar process. The objective was to investigate the morphological features of the region of the lateral pterygoid that inserted into the medial surface of the condylar process.

MATERIAL AND METHODS

Ten head halves of seven cadaveric donors were analyzed. In all specimens, the insertion area on the medial surface of the condylar process was measured based on microcomputed tomography images. Muscle fibers were separated into ≥50 small bundles, and positional relationships between the origins and insertions were investigated.

RESULTS

Overall, 28.8 ± 5.0% of the insertion area of the lateral pterygoid was situated on the medial surface of the condylar process. Moreover, muscle fiber arrangement revealed that origins of the muscle bundles inserting into the medial surface in seven specimens posteriorly occupied the lateral plate of the pterygoid process longitudinally, whereas those in three specimens mainly occupied the posteroinferior portion.

CONCLUSIONS

Muscle bundle inserting on the medial surface of the condylar process had a broad insertion area and a distinct origin on the posterior region of the lateral plate of the pterygoid process. This muscle bundle could act as one of the significant subunits within the lateral pterygoid. Therefore, anatomical coordination mechanisms underlying jaw movement cannot be elucidated without considering this subunit.

Morphometric analysis of the mandibular fossa in dentate and edentulous patients: A cone beam computed tomography study

STATEMENT OF PROBLEM

Mandibular fossa roof thickness and lateral inclination could be associated with the presence of bone changes in the mandibular condyle in dentate and edentulous patients. However, literature regarding the relationship between the presence and absence of teeth and the morphologic features of the temporomandibular joint is lacking. This knowledge could provide a better understanding of changes affecting the correct functioning of the stomatognathic system.

PURPOSE

The purpose of this clinical study was to assess the mandibular fossa roof thickness and lateral inclination in relation to sex, presence or absence of teeth, and bone changes in the mandibular condyle through cone beam computed tomography (CBCT).

MATERIAL AND METHODS

CBCT scans of 100 individuals (50 dentate and 50 edentulous) were evaluated in terms of mandibular fossa roof thickness and lateral inclination. Bone changes in the mandibular condyle were classified dichotomously in relation to osteophytes, erosion, sclerosis, and flattening. Differences were assessed with the Student t test, the chi-square test, and 2-way analysis of variance (ANOVA), with Tukey post hoc tests (α=.05).

RESULTS

Sex was not related to mandibular fossa measurements. Edentulous participants showed a higher mandibular fossa lateral inclination (P<.001) and lower roof thickness (P=.001) than dentate participants. When the association between bone changes in the mandibular condyle was evaluated in dentate and edentulous groups, only sclerosis showed a statistically significant association (P<.001). The 2-way ANOVA showed that the mandibular fossa roof thickness was lower in edentulous participants in the presence of flattening and erosion and that the mandibular fossa lateral inclination was higher in the presence of osteophytes, erosion, and sclerosis (P<.001). Among dentate participants, the mandibular fossa lateral inclination was higher in the presence of flattening (P=.024).

CONCLUSIONS

Mandibular fossa roof thickness and lateral inclination are not associated with sex. However, tooth absence and bone changes in the mandibular condyle are related to mandibular fossa measurements.

Periostin Mediates Condylar Resorption via the NF-κB-ADAMTS5 Pathway

Although the up-regulation of periostin in osteoarthritic (OA) is found, its function on OA condyle caused by disc displacement is not clear. Our objective was to explore whether periostin has any effect on condylar resorption. We initially identified periostin-positive cells in temporomandibular joint osteoarthritic (TMJ-OA) cartilage. Furthermore, the vitro analysis confirmed that the expression of periostin in chondrocytes treated with a static pressure of 150 kpa and 200 kpa for 3 h by an in-house-designed pressure chamber. To explore the underlying mechanism, we found that periostin can induce IκBα phosphorylation and its subsequent degradation, leading to consequent p65 nuclear translocation and subsequent induction of ADAMTS5 expression, which is known to be detrimental to cartilage extracellular matrix production. Importantly, inhibiting NF-κB signaling, by BAY 11-7082 treatment, rescued periostin-induced ADAMTS5 up-regulation. This study elucidated the direct role of periostin in condylar resorption, which was found to occur via NF-κB-ADAMTS5 signaling. Inhibition of this pathway might provide a new strategy for TMJ-OA treatment.

Tissue-engineered vascularized patient-specific temporomandibular joint reconstruction in a Yucatan pig model

PURPOSE

Current pediatric temporomandibular joint (TMJ) reconstruction options are limited. The aim of this project was to develop a proof-of-principle porcine model for a load-bearing, customized, 3D-printed and bone morphogenic protein 2 (BMP-2)-coated scaffold implanted in a pedicled (temporal) flap as a regenerative approach to pediatric TMJ mandibular condyle reconstruction.

MATERIALS AND METHODS

Scaffolds were customized, 3D-printed based on porcine computed tomography, and coated with BMP-2. Two operations occurred: (1) implantation of the scaffold in temporalis muscle to establish vascularity and, (2) 6 weeks later, unilateral condylectomy and rotation of the vascularized scaffold (with preservation of superficial temporal artery) onto the defect. Six months later, pigs were sacrified. The experimental side (muscle-scaffold) and control side (unoperated condyle) were individually evaluated by clinical, mechanical, radiographic, and histologic methods.

RESULTS

Scaffolds maintained physical properties similar in appearance to unoperated condyles. Vascularized scaffolds had new bone formation. Condyle height on the reconstructed side was 68% and 78% of the control side. Reconstructed condyle stiffness was between 20% and 45% of the control side.

CONCLUSION

In our porcine model, customized 3D-printed TMJ scaffolds coated with BMP-2 and implanted in vascularized temporalis muscle have the ability to (1) reconstruct a TMJ, (2) maintain appropriate condylar height, and (3) generate new bone, without impacting functional outcomes.

Evaluation of Size of the Condyle in Vertical and Anteroposterior Skeletal Conditions with the Help of Cone-beam Computed Tomography

AIM

Evaluation of size of the condyle in various vertical and anteroposterior skeletal conditions with the help of cone-beam computed tomography (CBCT).

METHODS AND MATERIALS

In this study, 266 study participants were included consisting of 112 males and 144 females. The study participants were categorized as class I when -1° ≤ A point-nasion-B point angle (ANB) < 4°, class II when ANB ≥ 4°, and class III when ANB < -1°. The study participants were categorized as hypodivergent when the mandibular plane (MP) ≤ 23°, normodivergent when 23° < MP < 30°, and hyperdivergent when MP ≥ 30°. CBCT images were obtained for each subject and measurement of length, width, and height of the condyle was carried out. The data were collected and analysis of covariance test (ANCOVA) was used for statistical analysis. Statistical significance was adjusted at p ≤ 0.05.

RESULTS

The size of the condyle was smaller in females. The length of the condyle was similar in different anteroposterior and vertical positions with no significant difference. The width of the condyle and the height of the condyle were greatest in class III anteroposterior condition while they were lowest in class I condition. The width and height of the condyle were greatest in hypodivergent condition while they were lowest in hyperdivergent condition.

CONCLUSION

It was concluded that the height and width of the condyle vary considerably in different vertical and anteroposterior skeletal patterns and the size of the condyle was smaller in women as compared with men.

CLINICAL SIGNIFICANCE

The position of the condyle and its morphology are important features that constitute an important part of orthodontic treatment planning. The skeletal pattern of the patient has also an important effect on the diagnosis, planning of treatment, and prognosis in the orthodontic treatment.

[Effect of conservative treatment on jaw symmetry of children with unilateral condylar fracture]

PURPOSE

To investigate the effect of conservative treatment of unilateral condylar fractures on jaw symmetry in children.

METHODS

Twenty-four children with unilateral condylar fractures were divided into control group and experimental group according to the treatment methods, with 12 cases in each group. The control group received surgery, and the experimental group received conservative treatment with intermaxillary traction combined with occlusal pads. The treatment effects of the two groups were compared, and the imaging improvement, three-dimensional structure of the jaw, mandibular motor and occlusal relationship, and facial nerve injury were compared after treatment. SPSS 17.0 software package was used for statistical analysis.

RESULTS

There was no significant difference in the total effective rate, total effective rate of imaging, disturbance of occlusal relationship, and incidence of facial nerve injury between the two groups (P>0.05). The transverse diameter of the condyles was significantly longer in the experimental group than in the control group, and the width of the condyles and bony condylar deflection in the experimental group were significantly smaller than those in the control group (P<0.05). The degree of mouth opening after treatment in both groups was increased, which was more remarkably in the experimental group after treatment than in the control group (P<0.05).

CONCLUSIONS

Children with unilateral condylar fractures can obtain similar treatment effects with surgical treatment with conservative treatment. After treatment, the children's mandibular motor function and jaw symmetry are well restored.

[Classification for mandibular deviation and facial asymmetry and its clinical significance]

Judged from the clinical manifestations, etiological mechanisms and jaw morphological structures, malocclusions with mandibular deviation and facial asymmetry are classified into three main categories, i.e., those with mandibular positioning factors, those with mandibular condyle defects, and those with jaw congenital deformities. In the first category, three subtypes, including mandibular rotation caused by dentitional irregularities, by dental compensation and by habitual posturing, are further defined. In the second category, mandibular deviation caused by condylar asymmetrical resorption or hyperplasia are defined as the two subtypes. The third category is further divided into two subtypes, i.e., jaw and facial asymmetry resulting from maxillary or mandibular structural deformities. The prime goal of orthodontic therapy is to displace and restore the deviated mandible to its right position, followed by correction of occlusal intercuspation. As an important procedure of the whole treatment protocol, It is critical to detect and localize the correct mandibular position by manipulation and then register it by wax pattern and articulator transferring. For the cases with mandibular functional elements and condylar asymmetrical length, the treatment modalities include orthopedic repositioning of the mandible by using occlusal and bite plane, SGTB and SGHB therapies; for cases with growth and developmental anomalies, orthognathic intervention should be an optimal solution.

Evaluation of condylar surface CT values related to condylar height reduction after orthognathic surgery

This study was performed to evaluate the relationship between condylar height reduction and changes in condylar surface computed tomography (CT) values in jaw deformity patients following orthognathic surgery. Mandibular advancement by sagittal split ramus osteotomy (SSRO) with Le Fort I osteotomy was performed in class II patients, and mandibular setback by SSRO with Le Fort I osteotomy was performed in class III patients. The maximum CT values (pixel values) at five points on the condylar surface and the condylar height, ramus height, condylar square, ramus angle, and gonial angle in the sagittal plane were measured preoperatively and 1 year postoperatively. Disc position was classified as anterior disc displacement (ADD) or other types by using magnetic resonance imaging (MRI). Ninety-two condyles of 46 female patients were prepared for this study. Their temporomandibular joints (TMJs) were divided into two groups based on class (46 joints in class II and 46 joints in class III) and two groups based on the findings (25 joints with ADD and 67 joints with other findings). ADD with and without reduction was observed in two joints in the class III group and in 23 joints in the class II group. The distribution of ADD incidence had not changed 1 year after surgery. Condylar height decreased 1 year after surgery in both class II patients (mandibular advancement) (p < 0.0001) and class III patients (mandibular setback) (p = 0.0306). Similarly, condylar height decreased 1 year after surgery both in patients who showed ADD (p = 0.0087) and those with other types (p = 0.0023). Significant postoperative increases at all angle sites on the condylar surface were found in the class II (p < 0.05) and ADD (p < 0.05) groups. This study showed that an enhanced condylar surface CT value might be one sign of condylar height reduction related to sequential condylar resorption, in combination with ADD.

Volumetric evaluation of temporomandibular joints in patients with a chewing-side preference: a CBCT study

This study evaluated the influence of chewing-side preference on the volume of the mandibular condyle and coronoid process and the dynamic parameters of the temporomandibular joint (TMJ). Cone beam computed tomographic scans of both TMJs of 90 individuals with a chewing-side preference were obtained while the patients were in the closed-mouth and maximum mouth-opening positions (test power ≥ 0.80). The preferred chewing side was identified with a chewing gum test as well as by patient self-reports of preferred side and hemispheric dominance (ie, dominant side of the body). Two trained examiners assessed the volume of the mandibular condyle and coronoid process and the dynamic parameters of the TMJs on both sides. The volumes of the mandibular condyle on the 2 sides were compared using a paired t test (α = 0.05). McNemar and Bowker tests of symmetry (α = 0.05) were used for concordance analyses of the dynamic parameters of the TMJ on the chewing and nonchewing sides. No statistically significant difference was observed in the volume of the mandibular condyle (chewing gum test, P = 0.4548; interview, P = 0.7191; hemispheric dominance, P = 0.3471) or coronoid process (chewing gum test, P = 0.7718; interview, P = 0.8072; hemispheric dominance, P = 0.8301) on the chewing and nonchewing sides, regardless of the method used to identify chewing preference. The preferred chewing side also did not significantly affect the dynamic parameters of the mandibular condyle (P = 0.5538). Chewing-side preference does not influence the volume of the mandibular condyle or coronoid process or the dynamic parameters of the TMJ.

Assessment of Sagittal Condylar Guidance with Protrusive Inter-occlusal Method, Panoramic Radiographs, and Lateral Cephalogram: A Comparative Study

BACKGROUND

Condylar guidance can be determined using the clinical and radiographic methods. The present study was conducted to determine condylar guidance using the protrusive interocclusal wax method, panoramic radiographs, and lateral cephalogram.

AIMS

The aim of the study was to compare the correlation between sagittal condylar guidance with protrusive interocclusal method, panoramic radiographs, and lateral cephalogram.

MATERIALS AND METHODS

The present study was conducted on 82 dentulous subjects (males 41, females 41). In all subjects, interocclusal registration values and condylar guidance values were measured using panoramic radiographs and lateral cephalograms.

RESULTS

The mean ± SD protrusive interocclusal registration value on the left side was 34.01 ± 1.2 mm and 34.08 ± 1.4 mm on the right side. The panoramic radiographs showed 35.12 ± 1.6 mm on the left side and 35.16 ± 1.7 mm on the right side. The mean ± SD protrusive interocclusal registration values on the left side was 34.01 ± 1.2 mm on the left side and 34.08 ± 1.4 mm on the right side. Lateral cephalogram showed 34.35 ± 1.3 mm on the left side and 34.67 ± 1.6 mm on the right side. There was a significant difference between the methods (p < 0.05).

CONCLUSION

Sagittal condylar guidance can be evaluated using protrusive interocclusal method. Along with it, other methods such as panoramic radiographs and lateral cephalogram may also be used for recording condylar guidance.

CLINICAL SIGNIFICANCE

Lateral cephalogram and panoramic radiographs may be reliable in determining condylar guidance, which can be used in orthodontic treatment planning.

Treatment measures of hemimandibular hyperplasia and associated facial deformities

This study aims to show our institute's experience in the treatment of HH and its associated facial deformities in adults and growing adolescents and to investigate condylar remodeling and volumetric changes and long-term stability of orthognathic surgery in adults. The study included consecutive patients with clinical and radiological features of HH who underwent high condylectomy with or without simultaneous orthognathic surgery from 2013 to 2018. The clinical outcomes were assessed based on functional activities, TMJ pain, and recurrence. Postoperative 3D condylar remodeling and orthognathic stability were evaluated with the use of ITK-Snap and 3D Slicer. Thirteen patients (8 females and 5 males) with a mean age of 26.3 ± 5.79 years (range; 13-34 years) were included with facial asymmetry as the chief complaint. The patients were followed up for a minimum of 12 months and a maximum of 4 years (mean; 16.85 ± 10.04). There were no postoperative complications, and all patients achieved a satisfactory functional and aesthetic outcome using a one-stage surgical procedure. There was no incidence of recurrence or further asymmetries, with long-term stability at the selected points showing a mean difference of less than ±1 mm. The affected condylar volume was significantly reduced following high condylectomy, with mean changes between T1 and T2 of -144. 80 mm³ (p = .012). However, the contralateral condylar volume remained stable, with a mean change of 2.54 mm³ (p = .881). One-stage high condylectomy and orthognathic surgery is a viable measure for the treatment of HH and associated deformities in adults. High condylectomy in early adolescence could result in termination of the disease, and aesthetic improvement with further constant orthodontist-surgeon follow-up is required.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Does Three-Dimensional Plate Offer Better Outcome and Reduce the Surgical Time Following Open Reduction and Internal Fixation of Adult Mandibular Unilateral Subcondylar Fractures. A Randomized Clinical Study

PURPOSE

The management of the condyle fractures continue to be a source of perineal controversy in the field of oral and maxillofacial trauma. The aim of this study was to compare the surgical feasibility, functional outcome, and stability of fixation between the conventional miniplate and 3-dimensional plate in the management of adult mandibular unilateral subcondylar fractures.

MATERIALS AND METHODS

A prospective randomized clinical study with well-structured inclusion and exclusion criteria was carried out. Patients were allocated into Group A (Miniplates) and Group B (3-D Plates). The primary outcome variables were time taken for fixation, maximum mouth opening, occlusal stability, increase in angulation, and increase in the gap between fractured segments in the radiograph. The secondary outcome variables were needed for intermaxillary fixation (IMF) with guiding elastics and jaw movements. Statistical analysis was done using χ² test and student's t test with P value less than 0.05 indicating statistical significance.

RESULTS

Forty-four patients (40 male and 4 female) were enrolled, with 22 patients in each group. Time taken for fixation using 3-D plates was significantly lower than conventional miniplates (9.6 ± 0.9 minutes with P value 0.001). Although clinical parameters showed improved results for Group B, there was no statistical significance. Radiological parameters ie increase in angulation, and increase in the gap, showed statistically significant results. Group A had significant increases in the angulation of the fractured condyle at the end of the third and sixth months with a P value of 0.008 and 0.0001, respectively. The gap between the fractured segments was significantly increased in Group A at the end of the first and third months, with a P value of 0.022 and 0.003, respectively.

CONCLUSIONS

Our results concluded that 3-D plate offers superior fracture fragment stability and less displacement of the fractured segments. It has an added advantage of the ease of adaptation and shorter operating time.

Evaluation of Condylar Positional, Structural, and Volumetric Status in Class III Orthognathic Surgery Patients

BACKGROUND AND OBJECTIVES

The need to evaluate the condylar remodeling after orthognathic surgery, using three-dimensional (3D) images and volume rendering techniques in skeletal Class III patients has been emphasized. The study examined condylar positional, structural, and volumetric changes after bimaxillary or single-jaw maxillary orthognathic surgeries in skeletal Class III patients using the cone-beam computed tomography.

MATERIALS AND METHODS

Presurgical, postsurgical, and one-year post-surgical full field of view (FOV) cone-beam computed tomography (CBCT) images of 44 patients with skeletal Class III deformities were obtained. Group 1 underwent a bimaxillary surgery (28 patients: 24 females and 4 males), with mean age at the time of surgery being 23.8 ± 6.0 years, and Group 2 underwent maxillary single-jaw surgery (16 patients: 8 females and 8 males), with mean age at the time of surgery being 23.7 ± 5.1 years. After the orthognathic surgery, the CBCT images of 88 condyles were evaluated to assess their displacement and radiological signs of bone degeneration. Three-dimensional (3D) condylar models were constructed and superimposed pre- and postoperatively to compare changes in condylar volume.

RESULTS

Condylar position was found to be immediately altered after surgery in the maxillary single-jaw surgery group, but at the one-year follow-up, the condyles returned to their pre-surgical position. There was no significant difference in condylar position when comparing between pre-surgery and one-year follow-up in any of the study groups. Condylar rotations in the axial and coronal planes were significant in the bimaxillary surgery group. No radiological signs of condylar bone degeneration were detected one year after the surgery. Changes in condylar volume after surgery were found to be insignificant in both study groups.

CONCLUSIONS

At one year after orthognathic surgery, there were no significant changes in positional, structural, or volumetric statuses of condyles.

[Evaluations of the morphology and position of condyle and fossa of adolescent temporomandibular joint with Class Ⅱsubdivision malocclusions]

PURPOSE

To evaluate the morphology and position of condyle and fossa and joint space of adolescent temporomandibular joint with Class Ⅱ subdivision malocclusion, in order to provide a reference for diagnosis before treatment.

METHODS

The study sample consisted of 30 adolescent patients with Class Ⅱ subdivision malocclusions(9 males, 21 females, mean age 12.5 years) as the experimental group and 30 adolescent patients with Class Ⅰ malocclusions (11 males, 19 females, mean age 12 years) as the control group treated from June 2018 to December 2019 in Suzhou Stomatological Hospital. The long axis of condyle, short axis of condyle, the distance from the outer pole of condyle to sagittal midline, horizontal angle of condyle, Joint space(medial, inner, outer, anterior, superior, posterior), vertical height of condyle, width of joint fossa, depth of joint fossa, angle of posterior wall of the articular tubercle and vertical distance of bilateral condyle to horizontal line were measured on cone-beam CT(CBCT) images and analyzed with Dolphin Imaging 11.95. SPSS 23.0 software package was used for statistical analysis of the data.

RESULTS

In Angle Class Ⅱ subdivision malocclusion patients, there were significant differences in posterior joint space, horizontal angle of condyle, vertical height of condyle, width of joint fossa, depth of joint fossa and angle of posterior wall of the articular tubercle between neutral side and distal side(P<0.01). In Angle Class Ⅰ malocclusion patients, there was no significant difference in joint fossa morphology, condyle morphology and condyle position between right side and left side (P>0.05).

CONCLUSIONS

There may be differences in condyle position, condyle shape and joint fossa shape between patients with Class Ⅱ subdivision malocclusions and Class Ⅰ malocclusion patients. More attention should be paid to the temporomandibular joint in initial clinical examination and clinical orthodontic treatment.

3D Auto-Segmentation of Mandibular Condyles

Temporomandibular joints (TMJ) like a hinge connect the jawbone to the skull. TMJ disorders could cause pain in the jaw joint and the muscles controlling jaw movement. However, the disease cannot be diagnosed until it becomes symptomatic. It has been shown that bone resorption at the condyle articular surface is already evident at initial diagnosis of TMJ Osteoarthritis (OA). Therefore, analyzing the bone structure will facilitate the disease diagnosis. The important step towards this analysis is the condyle segmentation. This article deals with a method to automatically segment the temporomandibular joint condyle out of cone beam CT (CBCT) scans. In the proposed method we denoise images and apply 3D active contour and morphological operations to segment the condyle. The experimental results show that the proposed method yields the Dice score of 0.9461 with the standards deviation of 0.0888 when it is applied on CBCT images of 95 patients. This segmentation will allow large datasets to be analyzed more efficiently towards data sciences and machine learning approaches for disease classification.

Dimensional and Positional Associations between the Mandibular Condyle and Glenoid Fossa: A Three-dimensional Cone-beam Computed Tomography-based Study

AIM

This retrospective cross-sectional study investigated the dimensional and positional associations between the mandibular condyle and glenoid fossa (GF) using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

Seventy female subjects [140 temporomandibular joints (TMJs)] were divided into two groups. Group I included 35 subjects with normal facial profiles (NFPs) in which the soft tissue glabella, subnasal point, and the soft tissue chin are almost in the same straight line, while the 35 subjects in group II had abnormal facial profiles (AFPs) in which the same imaginary line is either convex or concave indicating variation from standard norms. Three-dimensional volume analyses were performed on CBCT images by digitizing all landmarks in three orthogonal planes to measure the dimensional and positional parameters of the condyle and GF. Then the Pearson's correlation coefficient was used to identify associations between different condyle and GF parameters.

RESULTS

Sagittal condylar surface area was significantly associated with all dimensional parameters of the GF (GF height, width, and surface area, condylar width, and the GF width and between the axial and coronal condylar surface area with GF height and GF width) on the right and left sides of both groups (p values ranging from 0.000 to 0.028). Positional associations were detected between the anteroposterior and mediolateral GF positions and the corresponding position of the mandibular condyles and between the anteroposterior condylar position and the vertical GF position on both sides of both groups (p values ranged from 0.000 to 0.015).

CONCLUSION

There is a strong association between the mandibular condyle and GF in both positional and dimensional measurements in patients with normal and abnormal facial profiles.

CLINICAL SIGNIFICANCE

Understanding the associations between the mandibular condyle and GF facilitates optimization of the treatment outcomes by increasing occlusal harmony and stability after orthodontic treatment, orthognathic surgery, or any prosthetic replacement.

A Case of Osteomyelitis of the Mandibular Condyle Secondary to Bisphosphonate-related Osteonecrosis of the Jaw

We present a case of osteomyelitis of the condyle secondary to bisphosphonate-related osteonecrosis of the jaw. A 77-year-old female was referred to our clinic with complaints of swelling in the left mandibular molar regions. The patient had been suffering from myeloperoxidase anti-neutrophil cytoplasmic antibody (MPOANCA) associated vasculitis and had been treated with glucocorticoids for 8 years, and oral bisphosphonates had been prescribed to prevent osteopenia secondary to glucocorticoids. Imaging examinations showed radiolucency of the left mandibular body. Based on the diagnosis of osteomyelitis of the mandibular body secondary to bisphosphonate-related osteonecrosis, the patient received antimicrobial therapy and was well-healed. However, the patient returned 8 weeks later complaining of acute left preauricular swelling. Computed tomography showed the destructive changes in the mandibular condyle. We speculated that the infection was caused by the local spread from osteomyelitis of the left mandibular body. The risk of jaw necrosis related to antiresorptive therapy is well known. In recent years, the number of older patients being administered glucocorticoids with bisphosphonates has increased; therefore, we must be attentive to the signs of infectious diseases of the jawbone in the aging because it can easily shift to osteomyelitis or osteonecrosis and spread infection through the marrow.

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

AIM

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Three-dimensional comparative evaluation of articular disc position and other temporomandibular joint morphology in Class II horizontal and vertical cases with Class I malocclusion

OBJECTIVE

To evaluate and compare articular disk position, condylar position, and joint spaces in Class II vertical, Class II horizontal, and Class I cases. The purpose was to assess the potential for development of temporomandibular disorders (TMDs) in the three groups.

MATERIALS AND METHODS

A sample of 75 cases, 25 cases in each group of Class I, Class II vertical, and Class II horizontal, were selected based on inclusion and exclusion criteria. Magnetic resonance imaging (MRI) assessments were made with a 1.5-Tesla basic system with a closed-mouth technique for evaluating articular disk position in the sagittal and transverse planes, condylar position, and joint spaces in the sagittal plane. Philips 3.0 software was used to analyze the MR images.

RESULTS

There was evidence of alterations in the temporomandibular joint (TMJ) morphology in both Class II vertical and Class II horizontal cases, with maximum discrepancy in Class II vertical cases. MRI evaluation suggested a tendency for antero-medial disk displacement with anteriorly positioned condyles in Class II vertical cases. The discrepancy was milder in the Class II horizontal group.

CONCLUSIONS

Class II vertical cases are more susceptible to the development of TMDs and should be subjected to TMJ evaluation before starting any orthodontic treatment to intercept and prevent a mild asymptomatic TMD from developing into a more severe form. Class II vertical cases should be subjected to MRI evaluation before starting any orthodontic treatment.

Comparison of the Condyle Sagittal Position of Class I and Class II Division 2 in Orthodontic Patients

AIM

To compare the condyle sagittal position of class I and class II division 2 in orthodontic patients.

MATERIALS AND METHODS

Fifty orthodontic cases (30 females and 20 males; 12-31 years) from the records of an Orthodontic Graduate Program were collected. Such cases presented cone-beam computed tomography (CBCT) as part of their initial diagnostic examinations. The study sample constituted two groups, i.e. class I and class II division 2 groups. A previously calibrated examiner performed the measurements of the images, representing the distance between the condyle and the articular surface of the glenoid fossa, both anteriorly (anterior disk space-ADS) and posteriorly (posterior disk space-PDS). Descriptive statistics were performed. Data were normally distributed, and parametric tests were used. Paired sample test was used to identify differences between the right and the left joints. Differences between class I and class II/2 groups were tested using independent t test. All statistical tests were interpreted at 5% significance level.

RESULTS

When the study groups were compared in relation to the dimensions observed for the right and the left ADS and PDS, no significant differences were detected. This study also calculated the differences between right and left disk spaces within the groups, and the differences were not significant for both class I and class II/2 groups.

CONCLUSION

The results demonstrated, after the performance of a CBCT comparative analysis, that there is no significant difference between class II/2 and class I orthodontic patients in relation to the condyle sagittal position.

CLINICAL SIGNIFICANCE

The results collected here refute the expectation of spontaneous mandibular anterior repositioning after correcting the overbite in class II/2 patients.

Low-dose cone-beam computed tomography in simulated condylar erosion detection: a diagnostic accuracy study

OBJECTIVES

The purpose of the present study was to assess the diagnostic accuracy of low-dose cone-beam computed tomography (CBCT) in the detection of simulated mandibular condyle erosions.

METHODS

102 simulated erosions were performed on the condyles of eight dry human mandibles. Each mandible was subjected to four CBCT scan protocols: high-definition (HD), normal definition (NORM), ultra-low-dose high-definition (ULD-HD), and ultra-low-dose normal definition (ULD-NORM). All scans were analyzed by two observers. The inter-observer and intra-observer agreement as well as the agreement with the gold standard were assessed. The sensitivity, specificity, positive-predictive value, negative-predictive value and accuracy of erosion detection were calculated.

RESULTS

A substantial to almost perfect agreement with the gold standard was found regarding the HD protocol and substantial agreement in NORM and ULD-HD protocols; however, moderate agreement was found regarding the ULD-NORM protocol. The sensitivity, specificity and accuracy values were highest for the HD protocol followed by the NORM and ULD-HD which showed comparable results; while, the ULD-NORM protocol showed the least values.

CONCLUSIONS

The studied ULD-HD CBCT protocol can be recommended for the detection of mandibular condylar erosions due to the reduced radiation dose; however, ULD-NORM is not advocated for similar clinical use.

Assessment of mandibular characteristics in patients affected with β-thalassaemia major: A retrospective case-control study

OBJECTIVE

Thalassemia is the most common hereditary blood disorder across the world. This study aimed to identify some mandibular features of thalassaemic patients and compare them with unaffected counterparts.

MATERIAL AND METHODS

This retrospective case-control study was carried out on lateral cephalograms of 60 subjects (26 males, 34 females) with class II malocclusion and age range of 11 to 15 years. The control group consisted of 60 non-thalassaemic subjects with class II malocclusion and similar chronological age, gender and vertical facial dimension. Based on the Jarabak index, the case and control subjects were classified into hyperdivergent, normodivergent and hypodivergent growth patterns. Four linear (ramus height, ramus width, mandibular depth, and antegonial notch depth) and 3 angular (symphyseal angle, gonial angle, and mandibular arc angle) cephalometric parameters were measured to represent mandibular morphology. The data were analysed using Chi-square test and Student's t-test.

RESULTS

No significant difference was found in linear measurements between thalassaemic patients and controls. The symphysis angle was significantly greater and the mandibular arc angle was significantly smaller in the total thalassaemic sample than the control individuals (P<0.001 and P=0.004, respectively). The difference in symphysis angle was significant in both hyperdivergent and normodivergent subjects (P=0.004 and P=0.002, respectively), whereas the difference in mandibular arc angle was only significant in the normodivergent subgroup P=0.001).

CONCLUSIONS

The smaller mandibular arc angle in the thalassaemic sample suggests a more superior than posterior growth direction of condyles compared with healthy individuals. The difference in symphyseal angle represents inherent differences in chin morphology between thalassaemic subjects and controls.

Condyle modeling stability, craniofacial asymmetry and ACTN3 genotypes: Contribution to TMD prevalence in a cohort of dentofacial deformities

Craniofacial asymmetry, mandibular condylar modeling and temporomandibular joint disorders are common comorbidities of skeletally disproportionate malocclusions, but etiology of occurrence together is poorly understood. We compared asymmetry, condyle modeling stability and temporomandibular health in a cohort of 128 patients having orthodontics and orthognathic surgery to correct dentofacial deformity malocclusions. We also compared ACTN3 and ENPP1 genotypes for association to clinical conditions. Pre-surgical posterior-anterior cephalometric and panometric radiographic analyses; jaw pain and function questionnaire and clinical examination of TMD; and SNP-genotype analysis from saliva samples were compared to assess interrelationships. Almost half had asymmetries in need of surgical correction, which could be subdivided into four distinct morphological patterns. Asymmetric condyle modeling between sides was significantly greater in craniofacial asymmetry, but most commonly had an unanticipated pattern. Often, longer or larger condyles occurred on the shorter mandibular ramus side. Subjects with longer ramus but dimensionally smaller condyles were more likely to have self-reported TMD symptoms (p = 0.023) and significantly greater clinical diagnosis of TMD (p = 0 .000001), with masticatory myalgia most prominent. Genotyping found two significant genotype associations for ACTN3 rs1671064 (Q523R missense) p = 0.02; rs678397 (intronic SNP) p = 0.04 and one significant allele association rs1815739 (R577X nonsense) p = 0.00. Skeletal asymmetry, unusual condyle modeling and TMD are common and interrelated components of many dentofacial deformities. Imbalanced musculoskeletal functional adaptations and genetic or epigenetic influences contribute to the etiology, and require further investigation.

Minimally invasive intraoral proportional condylectomy with a three-dimensionally printed cutting guide

The aim of this study was to describe the steps of a minimally invasive surgical technique used to perform a proportional intraoral condylectomy with a three-dimensionally (3D) printed cutting guide. The technique consists of two steps: virtual surgical planning and intraoral condylectomy. During virtual surgical planning, the mandibular ramus was measured bilaterally, the height of the proportional condylectomy was planned virtually, and a cutting guide was 3D printed. In the intraoral condylectomy, the mandibular condyle was approached intraorally, the 3D printed cutting guide was positioned in the sigmoid notch, and the proportional condylectomy was performed. The protocol reported in this technical note is the sum of knowledge acquired from a series of studies published previously by the authors, who have jointly developed a surgical technique that is both minimally invasive and accurate for the treatment of condylar hyperplasia.

Evaluation of Imaging Software Accuracy for 3-Dimensional Analysis of the Mandibular Condyle. A Comparative Study Using a Surface-to-Surface Matching Technique

The aim of this study was to assess the accuracy of 3D rendering of the mandibular condylar region obtained from different semi-automatic segmentation methodology. A total of 10 Cone beam computed tomography (CBCT) were selected to perform semi-automatic segmentation of the condyles by using three free-source software (Invesalius, version 3.0.0, Centro de Tecnologia da Informação Renato Archer, Campinas, SP, Brazil; ITK-Snap, version2.2.0; Slicer 3D, version 4.10.2) and one commercially available software Dolphin 3D (Dolphin Imaging, version 11.0, Chatsworth, CA, USA). The same models were also manually segmented (Mimics, version 17.01, Materialise, Leuven, Belgium) and set as ground truth. The accuracy of semi-automatic segmentation was evaluated by (1) comparing the volume of each semi-automatic 3D rendered condylar model with that obtained with manual segmentation, (2) deviation analysis of each 3D rendered mandibular models with those obtained from manual segmentation. No significant differences were found in the volumetric dimensions of the condylar models among the tested software (p > 0.05). However, the color-coded map showed underestimation of the condylar models obtained with ITK-Snap and Slicer 3D, and overestimation with Dolphin 3D and Invesalius. Excellent reliability was found for both intra-observer and inter-observer readings. Despite the excellent reliability, the present findings suggest that data of condylar morphology obtained with semi-automatic segmentation should be taken with caution when an accurate definition of condylar boundaries is required.

Association between condylar position changes and functional outcomes after condylar reconstruction by free fibular flap

OBJECTIVES

Stable and appropriate condyle positioning is necessary for maintaining temporomandibular joint function. It is unclear if this position remains stable in patients after free fibular flap (FFF) condylar reconstruction. We investigated whether condylar position deviated after reconstruction, and whether this affected functional recovery.

MATERIALS AND METHODS

We retrospectively reviewed 43 patients who underwent conventional FFF condylar reconstruction, and 5 patients who underwent reconstruction by computer-assisted three-dimensional (3D) printing methods. Three-dimensional models were built from cone-beam computed tomography images obtained immediately postoperatively and 1-year postoperatively. The glenoid fossa and fibular condyle centers were used to measure the fibular condyle position in the models. Clinical examination indices, including maximum mouth opening (MMO), pain during chewing/mouth opening, and patient satisfaction with mastication and 1-year outcomes were assessed.

RESULTS

Fibular condyle position changed significantly over 1 year in both groups (P < 0.05). Clinical examination at 1 year after the surgery showed that in the conventional group, the MMO range was ≥ 35 mm in 76.7% of patients and < 35 mm in 23.3% of patients; 4.7% experienced pain during chewing/mouth opening, and 7% were dissatisfied with treatment outcomes. In the 3D printing group, all patients had an MMO range exceeding 35 mm, none had pain, and all were satisfied with functional outcomes.

CONCLUSIONS

The position of the fibular condyle deviates after reconstructive surgery, but it is unlikely to affect functional recovery.

CLINICAL RELEVANCE

These findings can form the basis for evaluation of functional outcomes of patients who have previously undergone condylar reconstruction by FFF.

Effects of rapid maxillary expansion on temporomandibular joints

OBJECTIVE

To evaluate the impact of rapid maxillary expansion (RME) on the condylar position, disc joint, joint space, and interarticular relationship in growing patients.

MATERIALS AND METHODS

A systematic search was performed in nine databases. The clinical studies selected included those with pre- and post-magnetic resonance, conventional computed tomography or cone beam tomography in growing patients. Risk of bias assessment was performed using the Cochrane Collaboration tool for controlled clinical studies and National Heart, Lung, and Blood Institute (NHLBI) Quality Assessment for Before-After Studies With No Control Group.

RESULTS

Initially, 4303 records were identified. Only eight studies fulfilled the criteria and were included in the qualitative analysis. Of those, two were controlled clinical studies with a risk of uncertain to high bias. The remaining papers had a low to moderate risk of bias. Results showed that RME in children and adolescents promoted the following: remodeling in the head and or condylar branch, changes in condylar position and joint space, maintenance of improved symmetry between the condyles, and no ability to modify the position or shape of the articular disc.

CONCLUSIONS

RME in growing patients is able, in the short term, to modify the condyle-fossa relationship but does not change the position or shape of the articular disc. The intercondylar symmetric relationship is maintained or improved. Although the NHLBI score shows low to moderate risk of bias, the clinical relevance of these review findings is limited by Cochrane and Grades of Recommendation, Assessment, Development and Evaluation scores.

Osteosynthesis of the Mandibular Condyle With Magnesium-Based Biodegradable Headless Compression Screws Show Good Clinical Results During a 1-Year Follow-Up Period

PURPOSE

The use of titanium-based implants in mandibular condyle fractures can require implant removal because of screw penetration through the condylar surface. The use of biodegradable implants can avoid a second operation for implant removal and the associated possible complications. We investigated the clinical and radiologic outcomes of osteosynthesis of mandibular condyle fractures (MCFs) with biodegradable magnesium-based compression screws.

MATERIALS AND METHODS

We performed a retrospective observational study of 6 patients who had been treated at our department. We recorded the changes in jaw movements over time, occlusion, and possible complications at defined intervals of 1, 3, 6, and 12 months postoperatively. We also compared the preoperative computed tomography (CT) scans with the postoperative cone-beam CT (CBCT) scans at 6 and 12 months postoperatively to evaluate mandibular condyle healing and screw degradation.

RESULTS

Of the 6 patients, 4 were men and 2 were women, with a mean age of 43.2 years (range, 30 to 66 years). All 6 patients had unilateral MCFs. All the patients showed well-restored function of the temporomandibular joint with significant improvement in mouth opening (46.17 ± 6.49 mm), right (10.67 ± 1.03 mm) and left (10.67 ± 1.97 mm) laterotrusion, and protrusion (10.17 ± 1.33 mm) distances to physiologic values. The CBCT scans showed the remodeling processes of the mandibular condyle and a few radiolucencies indicating the magnesium-based screws. Although penetration of 1 screw tip through the condylar surface had occurred, no implant removal was necessary owing to biodegradation of the implant.

CONCLUSIONS

The results of the present study have shown that biodegradable magnesium-based compression screws provide good clinical results and avoid implant removal.

Semi-automated three-dimensional volumetric evaluation of mandibular condyles

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Evaluation of 2 ultrasonic indicators as predictors of difficult laryngoscopy in pregnant women: A prospective, double blinded study

BACKGROUND

Ultrasonic measurements of tongue thickness and condylar translation were recently introduced to predict difficult laryngoscopy in non-obstetric patients. We designed the present study to evaluate the performance of these two ultrasonic indicators in predicting difficult laryngoscopy in healthy parturients.

METHODS

The 119 parturients undergoing elective cesarean delivery were enrolled. Tongue thickness and condylar translation measured by ultrasonography, and Modified Mallampati test (MMT) score, inter-incisor distance (IID) and modified Cormack-Lehane grading system (MCLS) were measured and recorded before anesthesia. The primary outcome was difficult laryngoscopy defined as MCLS 3 or 4. The association between these variables and difficult laryngoscopy were analyzed by using multivariable logistic regression and receiver operating characteristic (ROC) curve.

RESULTS

Compared to the Easy Laryngoscopy Group, the tongue thickness was significantly higher and the condylar translation and IID were significantly lower in the Difficult Laryngoscopy Group. Tongue thickness and condylar translation but not MMT score and IID were proved to be two independent predictors for difficult laryngoscopy by multivariate logistic regression, with the odds ratios of 2.554 (95% confidence interval (CI), 1.715 to 3.802) and 0.457 (95% CI, 0.304 to 0.686). The area under the ROC curve to predict difficult laryngoscopy for tongue thickness was 0.93 (95% CI, 0.88-0.98) and for condylar translation was 0.77 (95% CI, 0.67-0.86), which were significantly higher than those for MMT score (0.67, 95% CI, 0.56-0.77) and IID (0.65, 95% CI, 0.55-0.76).

CONCLUSIONS

Compared with MMT and IID, tongue thickness and condylar translation measured by ultrasonography appear to be better indicators for predicting difficult laryngoscopy in parturients.The trial was registered at the Chinese Clinical Trial Registry (ChiCTR)(www.chictr.org), registration number ChiCTR-ICR-1800019991.

[Comparison of skeletal structure of temporomandibular joint through cone-beam CT between Angle ClassⅠ, Ⅱ1, Ⅱ2, Ⅲ malocclusion patients with permanent dentition]

PURPOSE

To compare characteristics of temporomandibular joint and related structures according to gender and Angle Ⅰ, Ⅱ¹, Ⅱ² and Ⅲ class.

METHODS

Cone-beam CT (CBCT) was performed in 123 patients with malocclusion, and three-dimensional reconstruction was performed with Mimics 19.0 software. The anterior, upper, and posterior spaces of temporomandibular joint, width and depth of acetabulum, height and horizontal angle of condyle, radius of condyle, and anteroposterior and long-axis diameter of condyle were analysed on sagittal plane. The position of condyle in the joint fossa was analyzed using Pullinger methods. SPSS 22.0 software package was used for statistical analysis.

RESULTS

Significant differences were found in the long axis and radius of the condyles between Class Ⅰ and Ⅲ, Class Ⅰ and Ⅱ¹, respectively (P<0.05). The widest acetabulum was observed in Class Ⅲ, followed by Class Ⅰ, Ⅱ¹, and Ⅱ². Moreover, the deepest acetabulum was found in Class Ⅱ², followed by Class Ⅱ¹, Ⅰ, and Ⅲ. No significant differences were detected in the left and right condyle-related structures among different temporomandibular articulation. In addition, the anterior articular space was significantly larger in Class Ⅰ patients, compared with Class Ⅱ² patients.

CONCLUSIONS

There are significant differences in condylar morphology, joint space, joint fossa morphology and condylar position between different Angle classifications.

Evaluation of condyle-fossa relationships in adolescents with various skeletal patterns using cone-beam computed tomography

OBJECTIVES

To evaluate the condyle-fossa relationship in adolescents with various skeletal patterns using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

CBCT images obtained in 120 adolescent patients were used for this study. The patients were divided into 3 groups according to 3 criteria: (1) age (early, middle, and late adolescence); (2) facial height ratio or Jarabak quotient (hyperdivergent, normodivergent, and hypodivergent); and (3) ANB classification (Class I, Class II, and Class III). Temporomandibular joint space (TMJS: AS, anterior space; SS, superior space; PS, posterior space; MS, medial space; LS, lateral space), width and depth of the condyle (MLT, mediolateral thickness; APT, anteroposterior thickness), articular slope (ArS) and vertical height of the fossa (VHF) were measured and compared using CBCT.

RESULTS

Differences in condyle-fossa relationships were not significantly different between male and female adolescents, but were significantly different (P < .05) between left and right sides. The mean values showed no statistical differences according to age and skeletal pattern. Most measurements in the sagittal view showed that SS was the greatest, and the mean ratio of AS to SS to PS was 1.00 to 1.27 to 1.19, respectively. The mean values of coronal MS and LS were not significantly different.

CONCLUSIONS

There were almost no statistical differences in the TMJS in adolescents across various factors except between left and right sides.

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

OBJECTIVES

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

Software comparison to analyze bone radiomics from high resolution CBCT scans of mandibular condyles

OBJECTIVES

Radiomics refers to the extraction and analysis of advanced quantitative imaging from medical images to diagnose and/or predict diseases. In the dentistry field, the bone data from mandibular condyles could be computationally analyzed using the voxel information provided by high-resolution CBCT scans to increase the diagnostic power of temporomandibular joint (TMJ) conditions. However, such quantitative information demands innovative computational software, algorithm implementation, and validation. Our study's aim was to compare a newly developed BoneTexture application to two-consolidated software with previous applications in the medical field, Ibex and BoneJ, to extract bone morphometric and textural features from mandibular condyles.

METHODS

We used an imaging database of HR-CBCT TMJs scans with an isotropic voxel size of 0.08 mm3 . A single group with 66 distinct mandibular condyles composed the final sample. We calculated 18 variables for bone textural features and 5 for bone morphometric measurements using the Ibex, BoneJ and BoneTexture applications. Spearman correlation and Bland-Altman plot analyses were done to compare the agreement among software.

RESULTS

The results showed a high Spearman correlation among the software applications ( r = 0.7-1), with statistical significance for all variables, except Grey Level Non-Uniformity and Short Run Emphasis. The Bland-Altman vertical axis showed, in general, good agreement between the software applications and the horizontal axis showed a narrow average distribution for Correlation, Long Run Emphasis and Long Run High Grey Level Emphasis.

CONCLUSIONS

Our data showed consistency among the three applications to analyze bone radiomics in high-resolution CBCT. Further studies are necessary to evaluate the applicability of those variables as new bone imaging biomarkers to diagnose bone diseases affecting TMJs.

The effects on the mandibular condyle of Botox injection into the masseter are not transient

OBJECTIVES

To evaluate whether the effects on the mandibular condylar cartilage (MCC) and subchondral bone are transient of botulinum neurotoxin (Botox) injection into the masseter muscle.

METHODS

Botox (0.3 U) was injected into the right masseter of 6-week-old female mice (C57BL/6; n = 16). In addition, 16 mice were used as control and received no injections. Experimental and matching control mice were killed 4 or 8 weeks after the single Botox injection. Mandibles and mandibular condyles were analyzed by means of microscopic computed tomography (microCT) and histology. Sagittal sections of condyles were stained for tartrate-resistant acid phosphatase (TRAP), toluidine blue, 5-ethynyl-2'-deoxyuridine (EdU), and terminal deoxynucleotide transferase-mediated dUTP nick-end labeling.

RESULTS

Bone volume fraction was significantly decreased on the subchondral bone of the Botox-injected side, compared with the control side and control mice, 4 and 8 weeks after injection. Furthermore, histologic analysis revealed decrease in mineralization, cartilage thickness, TRAP activity, and EdU-positive cells in the MCC of the Botox-injected side 4 and 8 weeks after injection.

CONCLUSIONS

The effects on the MCC and subchondral bone of Botox injection into the masseter muscle persisted for 8 weeks after injection and were not considered to be transient.

Cone-beam CT evaluation of temporomandibular joint in permanent dentition according to Angle's classification

OBJECTIVES

To compare characteristics of temporomandibular joint (TMJ) and related structures according to Angle class I, II¹, II², and III.

METHODS

123 Chinese patients (13-36 years old, 60 males, and 63 females) were classified in four groups according to Angle's classification: skeletal class I (31 patients), skeletal class II division 1 (30 patients), skeletal class II division 2 (30 patients), and skeletal class III (32 patients). Left and right TMJs of each subject were evaluated independently with cone-beam computed tomography (CBCT). The position of condyle in the joint fossa was analyzed according to Pullinger.

RESULTS

There were significant differences between class III subjects and class I, II¹, II² in the superior joint space (p < 0.05). Compared with class II¹, II², and III subjects, the height and diameter of condyle in class I was significantly larger (p < 0.05). The width of joint fossa was significantly larger in Angle class III than in Angle class I, II¹, and II², while the depth was significantly smaller. The condyle position in class III subjects was more anteriorly displaced compared with that in class I subjects. In class II² patients, the condyle position was mainly concentric and posterior.

CONCLUSIONS

There are significant differences in condylar morphology, joint space, joint fossa morphology, and condylar position between different Angle classifications.

[Evaluation of occlusal reconstruction and cone-beam CT measurement of temporomandibular joint in patients with severe tooth wear]

PURPOSE

To explore the correlation between increased vertical dimensions and temporomandibular joint (TMJ) spaces of patients with severe tooth wear after occlusal reconstruction treatment.

METHODS

The TMJ spaces and the condylar positions of 30 patients were measured by cone-beam CT (CBCT) before and after treatment. SPSS 19.0 software package was used to analyze the anterior, superior and posterior space of TMJ. Independent sample t test was utilized to evaluate the correlation between vertical dimension and TMJ spaces.

RESULTS

There was no significant difference between TMJ spaces of two sides, the data of two sides were combined for further analysis. The mean anterior interspace, superior interspace, posterior interspace was (2.01±0.52)mm, (3.15±0.94)mm, (2.70±0.98)mm before treatment, and (2.03±0.35)mm, (3.46±0.74)mm, (2.79±0.58)mm after treatment, respectively. Based on calculating the In(P/A) and linear ratio(LR), condylar position moved backward for 52% patients before treatment. After occlusal reconstruction, the reduction rate of anterior displacement of condyle was 86.7%.

CONCLUSIONS

In addition to restoring its vertical dimensions of patients with severe tooth wear, the condyle should be induced to appropriate position to prevent TMJ symptoms.

Three-dimensional assessment of condylar position following orthognathic surgery using the centric relation bite and the ramal reference line: A retrospective clinical study

Orthognathic surgery (OGS) is a relatively common procedure for solving functional and aesthetic problems in facial and jaw areas in patients with dentofacial deformities. The positioning of the mandibular condylar segment during OGS has an impact on the surgical outcome. This study aimed to investigate the changes in the condyle-fossa relationship three dimensionally after OGS using the centric relation (CR) bite and the ramal reference line (RRL).Thirty-two patients with skeletal malocclusion underwent OGS. Condylar repositioning was performed using the CR bite, as previously reported. A RRL was added to the existing method and used during the surgery. Cone-beam computed tomography scans were acquired at 4 time points. Sixty-four condyles were evaluated in the coronal, sagittal, and axial views. Two groups were created according to the amount of mandible setback (SB1 vs SB2), and another 2 groups were created according to the maxillary operation (1-jaw vs 2-jaw). Each was then compared at the 4 time points. Differences between the values before (T0) and a year after surgery (T3) were also investigated. The positions of the pogonion and the menton were examined at T2 and T3 for the simple evaluation of relapse.The change in the condylar position was significant over a time-course (P < .001) but not between T0 and T3 (P > .05). Neither the setback amount nor the maxillary operation affected the positional change (P > .05). There were no significant changes between T2 and T3 in the relapse evaluation.This condylar repositioning method using the CR bite and a RRL showed stable results after OGS. This method is noninvasive and cost-effective and can be easily performed even by an inexperienced surgeon because it reduces errors in repositioning the condyle during OGS.

Is there an asymmetry of the condylar and coronoid processes of the mandible in individuals with unilateral crossbite?

OBJECTIVES

To evaluate if there is a true skeletal asymmetry of the condylar and coronoid processes of the mandible in growing individuals with unilateral posterior crossbite (UPC) either functional or not.

MATERIALS AND METHODS

This cross-sectional study screened a total of 1120 cone beam computed tomography (CBCT) scans based on inclusion and exclusion criteria. The final sample comprised 20 CBCT images of individuals with UPC and 19 CBCT images of individuals without transverse malocclusion. The lengths of the condylar and coronoid processes were measured to evaluate asymmetry, as well as the magnitude of the mandibular lateral deviation in the UPC group.

RESULTS

There was a significant difference between the lengths of the affected and nonaffected sides of the coronoid processes in the UPC group (P < .01). The same was not observed in the condyle in the UPC group (P > .05). There were no significant differences between the groups (P > .05).

CONCLUSIONS

Although no differences in the condyle were observed, the coronoid process was asymmetric in individuals with UPC. However, this asymmetry was not considered to be clinically significant.

Micro-CT observation of in vivo temporal change in mandibular condyle morphology in BMAL1 knockout mice

Brain and muscle Arnt-like protein-1 (BMAL1) knockout mice exhibit accelerated aging, abnormal glucose metabolism, and impaired adipocyte differentiation, among other phenotypes, which are effects associated with the BMAL1 gene. No study has investigated temporal changes in the deformation of the mandibular condyle and the presence of calcification in areas surrounding the mandibular condyle. In a study of 12 C57/BL strain mice under inhalation anesthesia, we collected images of the mandibular condyle at 6 weeks after birth and then every 5 weeks from 10 to 25 weeks after birth. At 25 weeks, deformation of the mandibular condyle was seen in 8 of 12 joints in BMAL1 knockout mice and in 2 of 12 joints in wild-type mice. At 20 and 25 weeks, deformation in areas surrounding the mandibular condyle, which are known to undergo calcification, was seen in 2 of 12 joints in BMAL1 knockout mice and in 0 of 12 joints in wild-type mice. BMAL1 knockout mice exhibited premature aging of the mandibular condyle, which suggests that circadian rhythms affect mandibular condyle morphology.

Comparison of four methods for quantitative assessment of 99mTc-MDP SPECT in patients with suspected condylar hyperplasia

OBJECTIVE

To compare variability, reproducibility and repeatability of four quantitative evaluation methods to interpret the ^99mTc-MDP SPECT reports in patients with clinically suspected unilateral condylar hyperplasia.

METHOD

This was a descriptive observational study carried out with SPECT images of 38 patients with clinical and radiographic signs of unilateral condylar hyperplasia, and interpreted using four quantitative methods: 1) one image, variable-size region of interest (ROI); 2) one image, fixed-size ROI (1.76cm²), 3) five image variable-size ROI; 4) five image, fixed-size ROI (1.76cm²). Each of the images was reported simultaneously (but in an independent way) by two nuclear medicine experts, in both total radioactive counts as well as normalized counts to evaluate the reproducibility (inter-operator variability) and the repeatability (intra-operator variability).

RESULTS

Higher reproducibility and repeatability were obtained in 5-image fixed-size ROI method (intra-class correlation coefficient: 0.979 [0.959; 0.989]). A high grade of diagnostic agreement (97.4%) was also attained in fixed methods (Kappa 0.940, p value: .000) from either total or normalized counts. There was no difference between fixed-size 1 vs 5 image methods. The methods based on variable-size ROI had a low grade of agreement (Kappa<0.20). More positive cases were identified using one image, ROI variable total counts (27 cases), but when the counts were normalized, they presented a lower number (5 cases).

CONCLUSION

Five-image fixed-size ROI provides the best intra-operator and inter-operator reliability for the diagnosis of unilateral condylar hyperplasia. In the four methods using normalized counts fewer positive cases were detected (≥10%), unlike with total counts when more positive cases were found.

TMJ arthrosis: does the occlusal relationship really interfere? A comparison between cone beam computed tomography and dried skulls

The aim of this study was to investigate the association between condylar bone morphological characteristics with occlusal conditions. Besides the study will compare the tomography images with the real condition in 122 temporomandibular joints from 61 skulls. The occlusal conditions were evaluated by number of teeth missing, measurement of overjet and overbite, in millimeters, and presence or absence of crossbite, openbite and dental rotation. The condylar bone morphological conditions were classified in five types (normal, presence of erosion, presence of osteophytes, flattening and/or deformation). This classification was used in real skulls and in Cone Beam Computed tomography (CBCT) images. The data were submitted to statistical analysis with a level of significance of 0.05. Occlusal variables have no association to morphologic data (p > 0.05). Normal condylar bone was seen in 62 CBCT versus 53 in real skulls while morphological alterations were seen in 60 CBCT versus 67-real condyles. The clinical and tomographic measurements were compared, demonstrating an important difference in the classification demonstrating poor association between detection methods (k - 0.3, p < 0.001). The occlusal conditions appear to have no correlation with the morphological condyle conditions. The CBCT is a reliable diagnostic method, although it may present divergences of findings when compared with clinical raw examination to morphologic condylar conditions.

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.