Changes In Condylar Position Research Articles

Condylar positions before and after bilateral mandibular distraction osteogenesis in children with Pierre Robin sequence

This study aimed to analyze the changes in mandibular morphology after bilateral mandibular distraction osteogenesis (BMDO) in children with Pierre Robin sequence. The positions of the condyles were analyzed in reconstructed three-dimensional craniomaxillofacial images obtained for 18 children before and 8–12 weeks after BMDO. Differences between pre- and postoperative parameters were assessed using paired t-tests. After surgery, a significant decrease in superior joint space was detected (P<0.05), but no change in anterior joint space or posterior joint space was observed. The ratio of the distance between gonia and distance between condylion points (GoL–GoR/CoL–CoR) (P<0.001) and the distances between the condyle and midsagittal plane (P<0.001) increased after surgery, while the condylar horizontal angle decreased (P<0.05). No change in condylar vertical angle was noted. After BMDO, the condyle displayed an outward and upward shift, as well as outward rotation along the proximal segment. The mandible body exhibited forward movement with a more significant opening range. These changes were consistent with the extent of the newly formed bone tissue and the improvement in coordination and appearance of the children’s facial structures. The long-term effects of changes in condylar position on the development of the maxillofacial structures needs to be studied further.

Changes in temporomandibular joint spaces after arthroscopic disc repositioning: a self-control study

Disc repositioning is a common procedure for patients with anterior disc displacement (ADD). The purpose of this retrospective record-based study was to evaluate changes in the widths of joint spaces and condylar position changes in patients with unilateral ADD following arthroscopic disc repositioning, with the healthy sides as self-control, using magnetic resonance images (MRI).Widths of anterior, superior, and posterior joint spaces (AS, SS, and PS) were measured. The condylar position was described as anterior, centric or posterior, expressed as . Paired-t test and Chi-square test were used to analyze the data. Fifty-four records conformed to the inclusion criteria (mean age of 21.02 years). Widths of SS and PS increased significantly after surgery (P < 0.001) on the operative sides, while joint spaces of healthy sides and AS of operative sides had no significant changes. Dominant location of condyles of operative sides changed from a posterior position to an anterior position, while healthy sides were mostly centric condylar position no matter preoperatively or postoperatively. Therefore, the results of this study indicate that unilateral arthroscopic disc repositioning significantly increases the posterior and superior spaces of the affected joints, without affecting spaces of the healthy sides.

Changes in condylar position after BSSRO with and without Le Fort I osteotomy via surgery-first approach in mandibular prognathism with facial asymmetry

This study aimed to evaluate changes in condylar position after bilateral sagittal split ramus osteotomy (BSSRO) with and without Le Fort I osteotomy via the surgery-first approach (SFA) in patients with facial asymmetry. Eighteen patients (36 condyles) who received surgical-orthodontic treatment using the SFA were included and divided into 2 groups depending on the extent of surgery: BSSRO-only group (n=12) and BSSRO with Le Fort I osteotomy group (n=6). Using computed tomography images taken preoperatively, immediately postoperatively, and 6months postoperatively, surgical and postoperative changes of the condylar position were analyzed 3-dimensionally. Both groups showed mainly inferolateral displacement with inward rotation immediately after surgery, and superomedial returning movement with outward rotation 6months after surgery. There was no statistical difference in time-course changes of the condylar position between the 2 groups. In comparing the deviated and nondeviated sides, the deviated side showed significantly greater amount of bodily shift and rotational movement after surgery compared with the nondeviated side in both groups. These results suggest that BSSRO via the SFA, either with or without Le Fort I osteotomy, may cause condylar displacement after surgery and that the displaced condyles return to their original position on both the deviated and the nondeviated sides.

Meta-analysis of the condylar position changes produced by functional appliances in class Ⅱ malocclusion

This study aimed to analyze the condylar position changes produced by functional appliances in class Ⅱ malocclusion by systematic review. Electronic search was conducted using Chinese Biomedical Literature Database, China National Knowledge Infrastructure, VIP Database for Chinese Technical Periodicals, Medline, Embase, Pubmed, and Cochrane Central Register of Controlled Trials. Studies on condylar position changes produced by functional appliances in class Ⅱ malocclusion were included. Risk of bias assessment and data extraction of included studies were conducted by two reviewers independently. The meta-analysis was carried out using Revman 5.1. Six studies were included (five high quality and one low quality). The condylar position showed no changes after Herbst treatment. The condylar posterior space after Twin-block treatment averagely increased by 0.31 mm (P<0.000 01), whereas the condylar anterior space averagely reduced by 0.32 mm (P<0.000 01). Twin-block appliance enables forward movement of the condylar position. This result contributes to the correction of class Ⅱ malocclusion.

Influence of the interocclusal splint in condylar position of patients with tmd: computed cone beam

The aim of this study was to evaluate the condylar position in patients with intra-articular temporomandibular disorders (TMD) before and after treatment with interocclusal stabilization splint (ISS) through computerized tomography cone beams (CTCB). Twenty-two patients diagnosed with intra-articular TMD (Research Diagnostic Criteria for Temporomandibular Disorders - Group II) were submitted to the therapy with ISS during 90 days. Three CTCB exams were performed in three moments: T1 – Initial moment, before the ISS therapy, with the patient in dental occlusion; T2 (after 90 days of treatment, in occlusion on the ISS) and T3 (after 90 days of treatment, with the patient in dental occlusion). Afterwards the anterior (AS), superior (SS) and posterior articular space (PS) in sagittal sections were then measured and the data were statistically analyzed using the t-test. There was a statistically significant increase in the comparison between T1 and T2 for the AS and PS (p&lt; 0.0001), between T3 and T2 for AS (p= 0.0008) and PS (p&lt; 0.0001). In comparison T1/T3 there was a significant increase in AS (p= 0.01) and SS (p= 0.04), and non-significant in PS (p= 0.89). The interocclusal splint provides temporary changes in condylar position, with a tendency to increase the joint space, varying in accordance with individual characteristics. Therefore, it should not be used as a single therapy, but combined with other strategies that include the TMD multidimensionality. The interocclusal splint has proved to be reversible and conservative therapeutic modality, as it does not generate permanent changes in joint tissues.

Condylar positional changes in rapid maxillary expansion assessed with cone-beam computer tomography.

The aim of this study was to determine the presence of condylar spatial changes in patients having rapid maxillary expansion treatments compared to a control group. Thirty-seven patients with maxillary transverse deficiency (11-17 years old) were randomly allocated into two groups (one treatment group -tooth borne expander [hyrax]- and one control group). Cone-beam computer tomographies (CBCT) were obtained from each patient at two time points (initial T1 and at removal of appliance at 6 months T2). CBCTs were analyzed using AVIZO software and landmarks were placed on the upper first molars and premolars, cranial base, condyles and glenoid fossa. Descriptive statistics, intraclass correlation coefficients and one-way Anova analysis were used to determine if there was a change in condyle position with respect to the glenoid fossa and cranial base and if there was a statistically significant difference between groups. Descriptive statistics show that changes in the condyle position with respect to the glenoid fossa were minor in both groups (<1.9mm average for both groups). The largest difference in both groups was found when measuring the distance between the left and right condyle heads. When comparing changes between both groups, no statistically significant difference was found between changes in the condyles (P<0.05). Rapid maxillary expansion treatments present mild effects/changes on the condylar position. Nevertheless, these changes do not present a significant difference with controls, thus not constituting a limitation for applying this treatment.

Sequential changes of postoperative condylar position in patients with facial asymmetry.

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. 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. 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). 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.

Early changes in condylar position after mandibular advancement: a three-dimensional analysis

The aim of this study was to perform a three-dimensional (3D) assessment of positional changes of the mandibular condyle after bilateral sagittal split osteotomy (BSSO). A prospective evaluation of 22 skeletal class II patients who underwent a BSSO for mandibular advancement was performed. Pre- and postoperative cone beam computed tomography scans were taken. Using the cranial base as a stable reference, the pre- and postoperative 3D skull models were superimposed virtually. Positional changes of the condyles were assessed with a 3D colour mapping system (SimPlant O&O). A Brunner–Langer statistical test was applied to test the null hypothesis that the condylar position remains stable after BSSO. The level of significance was set at 0.05. The mean mandibular advancement in the studied sample was 6.7±1.6mm. Overall, the condylar positional changes after BSSO for mandibular advancement were statistically significant (P<0.05). A positive correlation was found between the displacement of the left condyle and the amount of mandibular advancement (P<0.01). The results of this study suggest that statistically significant changes of condylar position occur after mandibular advancement. Long-term evaluation is needed to assess the capacity of the temporomandibular joint to adapt to these changes.

Radiographic cephalometry analysis of condylar position after bimaxillary osteotomy in patients with mandibular prognathism.

Postoperative condylar position is a substantial concern in surgical correction of mandibular prognathism. Orthognathic surgery may change condylar position and this is considered a contributing factor for early skeletal relapse and the induction of temporomandibular disorders. The purpose of this study was to evaluate changes in condylar position, and to correlate angular skeletal measurements following bimaxillary surgery. On profile teleradiographs of 21 patients with mandibular angular and linear parametres, the changes in condylar position, were measured during preoperative orthodontic treatment and 6 months after the surgical treatment. A statistically significant difference in values between the groups was found. The most distal point on the head of condyle point (DI) moved backward for 1.38 mm (p = 0.02), and the point of center of collum mandibulae point (DC) moved backward for 1.52 mm (p = 0.007). The amount of upward movement of the point DI was 1.62 mm (p = 0.04). In the patients with mandibular prognathism, the condyles tend to migrate upward and forward six months after bimaxillary surgery.

Changes in temporomandibular joint morphology in class II patients treated with fixed mandibular repositioning and evaluated through 3D imaging: a systematic review.

To estimate the effects of skeletal class II malocclusion treatment using fixed mandibular repositioning appliances on the position and morphology of the temporomandibular joint (TMJ). Two independent reviewers performed comprehensive electronic searches of MEDLINE, EMBASE, EBM reviews and Scopus (until May 5, 2015). The references of the identified articles were also manually searched. All studies investigating morphological changes of the TMJ articular disc, condyle and glenoid fossa with 3D imaging following non-surgical fixed mandibular repositioning appliances in growing individuals with class II malocclusions were included in the analysis. Of the 269 articles initially reviewed, only 12 articles used magnetic resonance imaging and two articles used computed tomography (CT) or cone-beam CT images. Treatment effect on condyle and glenoid fossa was discussed in eight articles. Treatment effect on TMJ articular disc position and morphology was discussed in seven articles. All articles showed a high risk of bias due to deficient methodology: inadequate consideration of confounding variables, blinding of image assessment, selection or absence of control group and outcome measurement. Reported changes in osseous remodelling, condylar and disc position were contradictory. The selected articles failed to establish conclusive evidence of the exact nature of TMJ tissue response to fixed mandibular repositioning appliances.

A Comparative Study of the Changes in Condylar Position after Mandibular Setback Using Bilateral Sagittal Split Ramus Osteotomy between Surgery-After and Surgery-First Orthognathic Surgery

Statement of the Problem: Complication after Extraoral Vertical and Intraoral Oblique Osteotomy have been reported but in a comprehensive manner. Although intuitively the profile of complications after Intra Oral Vertical Ramus Osteotomy (IVRO) would be similar to subcondylar osteotomy, the technique of the two procedures are different, and thus unfavorable outcome after surgery also may differ. The aim of this study was evaluate the morbidity and complications following correcton of mandibular deformity by IVRO. Material and Method: A prospective study was undertaken of 271 consecutively treated orthognathic surgical patients with mandibular deformity(without mandibular deficiency). Each patients was treated by bilateral IVRO with 2 Weeks of maxillo-mandibular fixation and no interosseous fixation of proximal segment. Method of Data Analysis: Postoperative stability ,immediately after surgery ,at 6 months , and at 12 months after surgeryweremade. Complications consist of vascular complications, nerve injury, infection, condylar luxation andbonehearingwere assessedby retrospective individual chart review. Results: The mean blood loss was 47g and no severe bleeding during operation. There was no wound infection and avascular necrosis after surgery. Inferior alveolar nerve neurosensory disturbance remained 2 operative sites but was not permanent. Malocclusion after surgery was manifest by either relapse or anterior open bite occurred in 3 patients. Condylar dislocation occurred 1 patient. Conclusion: Our studies indicated that surgical correction of mandibular deformity by IVRO had a beneficial effect not only on occlusion but also upon complication after surgery.

Immediate changes in condylar position after rapid maxillary expansion

Although the dentoalveolar and skeletal effects of rapid maxillary expansion are well documented, the condylar response to this procedure is not well understood. The purpose of this study was to test the following null hypothesis: rapid maxillary expansion promotes immediate changes of the position of the condyles in patients with Class I malocclusion. Thirty-four subjects with Class I malocclusion underwent rapid maxillary expansion. Cone-beam computed tomography images were collected before activation of the expander and 3weeks later, after screw stabilization. Using specific software functions, it was possible to determine and reproduce head positioning and landmarks during the different times of the study. The axial, coronal, and sagittal planes were examined, and no asymmetries in condylar positions were found at either time. However, statistically significant anterior and inferior displacements of these structures occurred, with respective average values of 0.52 and 0.49mm. Lateral inclinations of both condyles were observed and confirmed by the coronal condylar angles. The null hypothesis was rejected. Statistically significant anterior and inferior displacements of the condyles occurred. Lateral inclination of the condyles was observed.

Effective temporomandibular joint growth changes after stepwise and maximum advancement with Twin Block appliance

BackgroundThis study was designed to evaluate the “effective” temporomandibular joint changes (the sum of condylar modeling, glenoid fossa modeling, and condylar position changes within the fossa) and their influence on mandibular rotation in Class II Division 1 malocclusion cases treated with Twin Block appliance using a maximum and stepwise advancement approach. MethodsSixty Class II Division 1 cases with normal growth patterns in the age group of 12 to 14 years were treated with the Twin Block appliance and randomly assigned to one of two groups: 1) maximum advancement (n = 30); and 2) stepwise advancement (n = 30). The Bolton Standards served as a control group. Lateral head films were obtained before treatment and after successful treatment (mean 1 year). ResultsCompared with the control groups, both treatment groups showed significant vertical growth changes. Sagittal growth direction was posterior with maximum advancement and anterior with stepwise advancement. Resultant mandibular rotation was in the anterior direction and was greater with stepwise advancement. ConclusionsMyofunctional therapy after maximum and stepwise advancement with the Twin Block appliance showed a favorable effect in the temporomandibular joint region. Stepwise advancement showed greater vertical growth and more favorable anteriorly directed horizontal growth in the temporomandibular joint region on a short-term basis.

The mandibular response to occlusal relief using a flat guidance splint

BackgroundThe mechanism of action of occlusal splints used for the successful treatment of temporomandibular disorders (TMD) remains unclear and controversial.AimThe aim of this study was to observe the mandibular response during sleep bruxism (SB) on the elimination of occlusal influences by using a flat anterior and lateral guidance splint (FGS).Material and methodAny changes in mandibular movement patterns and condylar position with the introduction of this tool were measured. Current SB activity on the natural dentition was evaluated using a Brux Checker® (BC) and compared with the activity after insertion of an FGS in 153 subjects.ResultThe spatial mandibular position changed individually with a tendency toward forward and downward movement. The insertion of an FGS led to a change in the topographical condyle-fossa relationship and seemed to create an “unloading” condition for the temporomandibular joint. It was found that increased angulation of the maxillar incisors was responsible for altered muscular activity during sleep.ConclusionThe masticatory organ appears to self-regulate and to provide an oral behavior modification, which may be more physiological using the FGS as a compensating factor. In this context, it is assumed that sleep bruxism in terms of parafunctional activity is a physiological function of the masticatory organ. The results of this study indicate the importance of controlling anterior guidance in the functional reconstruction of human occlusion.

Short- and Long-Term Changes of Condylar Position After Bilateral Sagittal Split Ramus Osteotomy for Mandibular Advancement in Combination With Le Fort I Osteotomy Evaluated by Cone-Beam Computed Tomography

Bilateral sagittal split ramus osteotomy (BSSO) may change condylar position, which can be one of the factors contributing to skeletal relapse. This study evaluated short- and long-term changes in condylar position using cone-beam computed tomography (CBCT) and investigated changes in temporomandibular joint (TMJ) signs after BSSO for mandibular advancement in combination with Le Fort I osteotomy. Thirty-one patients were included, and CBCT data of 62 TMJs were collected before surgery (T0), immediately after surgery (T1), 3 months after surgery (T2), and at the last follow-up at 12.1 ± 3.0 months after surgery (T3). The relation of the condyle to the fossa was evaluated by the method of Pullinger and Hollender (Oral Surg Oral Med Oral Pathol 62:719, 1986). Clinical examination, with a special focus on signs of temporomandibular disorder (TMD), was documented at T0, T2, and T3. Repeated-measures analysis of variance (P = .05) and χ2 test (P = .05) were performed. Data of 27 patients were used for statistical analysis. Values from the formula of Pullinger and Hollender changed significantly with time, but there was no significant difference between the right and left condyles. Condyles moved inferoposteriorly immediately after surgery (T0 to T1) followed by anterosuperior movement 3 months after surgery (T1 to T2). The superimposed effect showed posterosuperior movement compared with the initial position before surgery (T0 to T2) and this position remained stable at 1-year follow-up (T2 to T3). A decrease of TMD signs over time, from 22.6% (T0) to 12.9% (T2) and 9.7% (T3), was observed, which showed no statistical significance. There were obvious changes in condylar position after BSSO in combination with Le Fort I osteotomy. Condyles tended to be located in a concentric position in relation to the glenoid fossa 3 months after surgery and remained stable during the 1-year follow-up. These changes did not cause an increase of TMD signs.

Change in condylar position in posterior bending osteotomy minimizing condylar torque in BSSRO for facial asymmetry

During the correction of an asymmetric mandible with sagittal split ramus osteotomy (SSRO), bony interference between the proximal and distal segments inevitably occurs. This results in positional change of the condyle. In order to avoid this, a posterior bending osteotomy (PBO) has been introduced. This is an additional vertical osteotomy posterior to the second molar after SSRO. To investigate the change in condylar position after SSRO with PBO, 22 patients with facial asymmetry were enrolled and divided into two groups based on the surgical method used to remove the bony interference after SSRO: PBO (n = 13) and the grinding method (n = 9). Each group was subdivided into large and small bony interference groups by estimating the volume of bony interference with simulation surgery. Condylar displacement was evaluated by three-dimensional superimposition and the amount of condylar displacement was calculated. The positional changes of the condyles were variable in each patient. When comparing patients with large bony interference in the PBO and grinding groups, the condyles were significantly inwardly rotated in the grinding group (p < 0.05). The grinding method can be used to remove small bony interferences with tolerable condylar torque. However, PBO would be beneficial in correcting large bony interferences while minimizing condylar torque.

Long-Term 3-Dimensional Stability of Mandibular Advancement Surgery

To evaluate 3-dimensional changes in the position of the condyles, rami, and chin from 1 to 3 years after mandibular advancement surgery. This prospective observational study used pre- and postoperative cone-beam computed tomograms of 27 subjects with skeletal Class II jaw relation and normal or deep overbite. An automatic technique of cranial base superimposition was used to assess positional and bone remodeling changes that were visually displayed and quantified using 3-dimensional color maps. Analysis of covariance with presence of genioplasty, age at time of surgery, and gender as explanatory variables was used to estimate and test adjusted mean changes for each region of interest. The chin rotated downward and backward 1 to 3 years after surgery. Changes of at least 2 mm were observed in 17% of cases. Mandibular condyles presented with displacements or bone remodeling of at least 2 mm on the anterior surface (21% of cases on the left side and 13% on the right), superior surface (8% on right and left sides), and lateral poles (17% on left side and 4% on right). Posterior borders of the rami exhibited symmetric lateral or rotational displacements in 4% of cases. In the hierarchy of surgical stability, mandibular advancement surgery is considered one of the most stable surgical procedures. However, 1 to 3 years after surgery, approximately 20% of patients had 2- to 4-mm changes in horizontal and vertical chin positions or changes in condylar position and adaptive bone remodeling.

Evaluation of Condylar Resorption Before and After Orthognathic Surgery

Malpositioned condyles during osteotomy can cause remodeling of the condyles, but can also initiate condylar resorption (CR). The radiological signs of CR are similar to juvenile osteoarthritis and osteoarthrosis. In the 1980s, conventional transcranial and infracranial radiographs were used to evaluate the position of the condyle in the fossa. An orthopantomogram can be used to describe the contour or morphology of the condyles, but it is not applicable for measurements. Magnetic resonance imaging is useful in evaluation of the disks, condyles, and synovia. Both conventional multislice computed tomography and cone-beam computed tomography (CBCT) can provide an excellent visualization of the condyles in 3 planes. With CBCT, condylar position and condylar changes can be assessed as a color-coded map, or as mesh transparencies, which provide higher accuracy. The pretreatment assessment of past or potential temporomandibular joint (TMJ) issues consists of a detailed history of previous TMJ symptoms, as well as a clinical and radiological examination. An orthopantomogram is helpful to make a risk profile based on the contour of a condyle and the stage of osteoarthritic degeneration. After orthognathic surgery, the surgeon must be aware of TMJ dysfunction symptoms, occlusal relapse, reduction of form and volume of the condyle, and loss of mandibular ramus height. In patients with a high risk for CR or when a suspicion of CR occurs, a CBCT is indicated. The incorporation of an automated postscan image enhancement protocol and subsequent 3-dimensional rendering of condyles into the 3-dimensional virtual head model of patients will provide a powerful tool for analysis of CR. Malpositioned condyles during osteotomy can cause remodeling of the condyles, but can also initiate condylar resorption (CR). The radiological signs of CR are similar to juvenile osteoarthritis and osteoarthrosis. In the 1980s, conventional transcranial and infracranial radiographs were used to evaluate the position of the condyle in the fossa. An orthopantomogram can be used to describe the contour or morphology of the condyles, but it is not applicable for measurements. Magnetic resonance imaging is useful in evaluation of the disks, condyles, and synovia. Both conventional multislice computed tomography and cone-beam computed tomography (CBCT) can provide an excellent visualization of the condyles in 3 planes. With CBCT, condylar position and condylar changes can be assessed as a color-coded map, or as mesh transparencies, which provide higher accuracy. The pretreatment assessment of past or potential temporomandibular joint (TMJ) issues consists of a detailed history of previous TMJ symptoms, as well as a clinical and radiological examination. An orthopantomogram is helpful to make a risk profile based on the contour of a condyle and the stage of osteoarthritic degeneration. After orthognathic surgery, the surgeon must be aware of TMJ dysfunction symptoms, occlusal relapse, reduction of form and volume of the condyle, and loss of mandibular ramus height. In patients with a high risk for CR or when a suspicion of CR occurs, a CBCT is indicated. The incorporation of an automated postscan image enhancement protocol and subsequent 3-dimensional rendering of condyles into the 3-dimensional virtual head model of patients will provide a powerful tool for analysis of CR.

Disc displacement and changes in condylar position

To determine whether disc displacement (DD) can be a factor causing changes in condylar position in the glenoid fossa, using limited cone beam CT (LCBCT) images taken in the same time period as MRI that verified DD. The study included 60 joints in 57 male and female subjects aged 12-20 years (mean age 14.8 years). Subjects fulfilling the inclusion criteria were enrolled from a pool of post-orthodontic patients, and divided into four groups according to their disc status confirmed by MRI: partial DD (PDD), total DD with reduction (TDDWR), lateral DD (LDD) and medial DD (MDD). Changes in joint space from previously reported norms were measured on LCBCT images. In PDD, the condyles were displaced posteriorly in the fossae with a mean anterior space of 2.7 ± 0.5 mm (normal 1.3 ± 0.2 mm) and a posterior space of 1.8 ± 0.4 mm (normal 2.1 ± 0.3 mm). In TDDWR, the condyles were displaced not only posteriorly as observed in PDD, but also vertically with a reduced superior space of 1.9 ± 0.4 mm (normal 2.5 ± 0.5 mm). In LDD, the lateral space was significantly increased to 2.5 ± 0.3 mm (normal 1.8 ± 0.4 mm), while central and medial spaces were significantly decreased to 2.2 ± 0.5 mm (normal 2.7 ± 0.5 mm) and 1.7 ± 0.4 mm (normal 2.4 ± 0.5 mm), respectively. In MDD, the medial space was increased and the lateral and central spaces were significantly decreased. These results indicate that DD in adolescents and young adults can cause the condyle to change its position in the fossa with alterations in joint space which depend on the direction and extent of DD.

Changes in Condylar Position Using Different Types of Splints With and Without a Chinstrap: A Case-Control Study

The aim of this case-control study was to analyze and quantify if there is a different mechanical effect of stabilization and pivot splints with uni- or bilateral pivot of different heights and with and without an additional chinstrap, on the vertical, sagittal, and horizontal condyle position. A stabilization splint and splints with unilateral or bilateral posterior pivot support of 0.6 mm or 1.9 mm height were used with and without a chinstrap individually adjusted to 5N per side. Electronic-condylar-positionanalysis was performed using an ultrasound-based jaw-tracking system with an accuracy of 0.1 mm. Manual guided central position served as the reference point. Participants were 40 functional, asymptomatic volunteers with a mean age of 33.9 years. Main effect splint design (stabilization, uni-, bilateral pivot) was not significant. Pivoting height was reported as significant (p≤00.02) in all axes. Use of the chinstrap was significant (p≤0.03) in the X- and Y- axis, but not significant in the Z-axis. A post-hoc test revealed that use of a chinstrap led to significantly (p=0.003) less anterior and significantly (p=0.002) more inferior condyle displacement. Results indicate that the use of pivot splints only in combination with a chinstrap lead to a distractive effect of the condyles.