Evaluation of Temporomandibular Function After High Partial Condylectomy Because of Unilateral Condylar Hyperactivity

The learning curve of transoral condylectomy; a retrospective analysis of 100 consecutive cases of unilateral condylar hyperplasia

In this study, 100 consecutive scheduled transoral condylectomies for unilateral condylar hyperplasia were included. The safety and surgical performances were assessed, using the operating time, conversion rate and complication rate. The conversion rate learning curve was evaluated with a learning curve cumulative summation (LC-CUSUM). The total conversion rate was 8.0%. The LC-CUSUM for conversion signaled at the 53th procedure, indicating sufficient evidence had accumulated that the surgeon had achieved competence. For procedures 54-100, the conversion rate was 4.0%. The operating time for the transoral condylectomy was 41.5 ± 15.3 min; when a conversion was necessary, the operating time was 101.4 ± 28.3 min (p < 0.05). The estimated operating time in the post-learning phase was 37 min, this was reached after approximately 47 procedures. There was 1 major complication of a permanent inferior alveolar nerve hypoesthesia. The complication rate was not significantly decreased after the learning curve. Within the limitations of the study, it seems that transoral condylectomy for UCH is a safe procedure with several advantages over the traditional preauricular approach. Surgeons starting this procedure should be aware of the potential complications and of the learning curve of approximately 53 procedures.

Early Treatment of Unilateral Condylar Hyperplasia in Adolescents: Preliminary Results

Facial asymmetry associated with unilateral condylar hyperplasia (UCH) is a rare disease. The aim of this study was to evaluate the clinical conditions of progressive facial asymmetry in young subjects treated with high condylectomy. A retrospective study was performed including nine subjects diagnosed with UCH type 1B and progressive facial asymmetry around 12 years old with an upper canine progressing towards dental occlusion. After an analysis and a decision of treatment, orthodontics began one to two weeks prior to the condylectomy (with a mean vertical reduction of 4.83 ± 0.44 mm). Facial and dental asymmetry, dental occlusion, TMJ status and an open/closing mouth were analyzed before surgery and in the final stage of treatment, almost 3 years after surgery. Statistical analyses were performed using the Shapiro-Wilk test and a Student's t-test considering a p value of <0.05. Comparing T1 (before surgery) and T2 (once orthodontic treatment was finalized), the operated condyle showed a similar height to that observed in stage 1 with a 0.12 mm difference in height (p = 0.8), whereas the non-operated condyle showed greater height increase with an average of 3.88 mm of vertical growth (p = 0.0001). This indicated that the non-operated condyle remained steady and that the operative condyle did not register significant growth. In terms of facial asymmetry in the preoperative stage, a chin deviation of 7.55 mm (±2.57 mm) was observed; in the final stage, there was a significant reduction in the chin deviation with an average of 1.55 mm (±1.26 mm) (p = 0.0001). Given the small number of patients in the sample, we can conclude that high condylectomy (approx. 5 mm), if performed early, especially in the mixed-dentition stage before full canine eruption, is beneficial for the early resolution of asymmetry and thus the avoidance of future orthognathic surgery. However, further follow-up until the end of facial growth is required.

Micro-computed tomography evaluation of bone architecture in various forms of unilateral condylar hyperplasia

Condylar hyperplasia is one of the causes of facial asymmetry and malocclusion, characterized by enlargement of the lower jaw due to excessive condyle growth activity. The aim of this study was to use micro-computed tomography (micro-CT) to evaluate the bone architecture of the condylar head and determine whether there are differences between patients with various forms of unilateral condylar hyperplasia (UCH): hemimandibular hyperplasia, elongation, and mixed form. The cohort consisted of 28 patients with a mean age of 21.9 years. All patients underwent surgical treatment (condylar shaving) for active pathological growth activity. The portion of the condylar head removed was imaged by micro-CT and subsequently evaluated. Micro-CT imaging and semiquantitative and quantitative evaluation of the bone structure (percentage bone volume, surface density, trabecular thickness, trabecular separation, degree of anisotropy, and porosity of the subchondral bone) did not reveal significant differences between the individual types of condylar hyperplasia (P > 0.05). There were no significant differences in bone structure between the anterior and posterior portions of the condylar head. No statistically significant differences between individual groups of UCH were found in the micro-CT evaluation of the condylar head bone architecture.

Tissue engineered autologous cartilage-bone grafts for temporomandibular joint regeneration

Joint disorders can be detrimental to quality of life. There is an unmet need for precise functional reconstruction of native-like cartilage and bone tissues in the craniofacial space and particularly for the temporomandibular joint (TMJ). Current surgical methods suffer from lack of precision and comorbidities and frequently involve multiple operations. Studies have sought to improve craniofacial bone grafts without addressing the cartilage, which is essential to TMJ function. For the human-sized TMJ in the Yucatan minipig model, we engineered autologous, biologically, and anatomically matched cartilage-bone grafts for repairing the ramus-condyle unit (RCU), a geometrically intricate structure subjected to complex loading forces. Using image-guided micromilling, anatomically precise scaffolds were created from decellularized bone matrix and infused with autologous adipose-derived chondrogenic and osteogenic progenitor cells. The resulting constructs were cultured in a dual perfusion bioreactor for 5 weeks before implantation. Six months after implantation, the bioengineered RCUs maintained their predefined anatomical structure and regenerated full-thickness, stratified, and mechanically robust cartilage over the underlying bone, to a greater extent than either autologous bone-only engineered grafts or acellular scaffolds. Tracking of implanted cells and parallel bioreactor studies enabled additional insights into the progression of cartilage and bone regeneration. This study demonstrates the feasibility of TMJ regeneration using anatomically precise, autologous, living cartilage-bone grafts for functional, personalized total joint replacement. Inclusion of the adjacent tissues such as soft connective tissues and the TMJ disc could further extend the functional integration of engineered RCUs with the host.

The need for secondary orthognathic surgery after high condylectomy in patients with active unilateral condylar hyperplasia

The need for secondary orthognathic surgery (OS) after a high condylectomy (HC) in patients with active unilateral condylar hyperplasia was assessed in 25 patients, reviewing patient characteristics and treatment planning. At 6-12 months after HC, 13 patients (52%) required secondary OS. The amount of mandibular dental midline shift before the HC (P=0.037), and a dental crossbite that was present before the HC (P=0.017) were significantly associated with the need for secondary OS. Overall, the mandibular dental midline coincided with the facial midline in eight patients (32%) at 2 weeks after HC. In 16% of the patients, no additional OS was needed despite this being the initial treatment plan. Additionally, the initially planned type of secondary OS was modified in six other patients. Early HC in skeletally immature patients provided very good results, both aesthetic and functional, with only two of them needing supplementary OS at 6-12 months after HC. The HC remains a valuable treatment in patients with active unilateral condylar hyperplasia, as it can eliminate the need for secondary OS and is very well tolerated by most patients.

Case Report: unilateral condylar hyperplasia

Case: This report describes a clinical case of unilateral condylar hyperplasia (CH) with unique, atypical morphology. An important feature of this report is the documentation of a series of clinical photographs of the patient, showing a gradual increase in facial asymmetry associated with the CH. The main symptom reported in this case was facial asymmetry. The main intraoral clinical features observed in the patient were contralateral crossbite and ipsilateral open bite associated with CH. Surgical reshaping of the condyle was the treatment plan for this case. Conclusions: The main take away point from this case is the importance of obtaining previous photographs of the patient at different ages during case diagnosis, which helps the clinician to determine the approximate time of commencement of CH. This case also highlights the imaging features of rarely observed atypical shape of the hyperplastic condyle.

An Updated Protocol for the Treatment of Condylar Hyperplasia: Computer-Guided Proportional Condylectomy

PURPOSE

To present an updated protocol for proportional condylectomy in which virtual surgical planning and 3-dimensional (3D) printing allow precise definition of the osteotomy level.

MATERIALS AND METHODS

Three-dimensional mirroring was performed to generate a virtual replica of the healthy hemimandible, which was subsequently aligned and overlapped with the actual mandible to estimate the level for condylectomy. A custom-fitted 3D printed surgical guide was modeled for the condylar head to reproduce the virtual plan in the surgical scenario. The updated protocol for computer-guided condylectomy was applied to 7 patients.

RESULTS

All patients were followed for 12 months. Surface deviation color maps showed a strong correspondence between the virtually calculated condylectomy and the surgical outcome achieved with the aid of the surgical guide. No cases of condylar hyperplasia recurrence were observed.

CONCLUSION

An updated protocol based on accurate 3D analysis was performed by virtual surgical planning and 3D printing. Virtual surgical planning allows the precise definition of the level of condylectomy, and custom-made 3D printed cutting guides are useful to reproduce virtual measurements during surgical maneuvers.

Condilectomia alta associada à discopexia, com mini-âncoras, no tratamento da hiperplasia condilar: relato de caso

Introdução: A hiperplasia condilar (HC) é uma patologia rara caracterizada por crescimento não neoplásico que afeta a morfologia do côndilo mandibular com deformação progressiva. Dentre os sinais mais comuns se encontram a assimetria facial e mandibular, além de possíveisalterações oclusais como mordida aberta ipsilateral e transversal contralateral. Objetivo: O objetivo do estudo foi demonstrar a eficácia terapêutica da condilectomia alta associada à discopexia, com mini-âncoras, no tratamento da hiperplasia condilar. Relato de caso: Paciente de 24 anos de idade, apresentando assimetria facial, déficit e incompetência funcional mastigatória, mordida aberta posterior ipsilateral e mordida cruzada posterior contralateral. A proposta terapêutica escolhida foi o tratamento cirúrgico com condilectomia alta e discopexia com âncora para estabilização do disco articular, através de acesso endaural para o côndilo afetado com tamponamento auricular. Foi realizado infiltração com ácido hialurônico intra-articular após sutura da cápsula articular e sutura por planos para sutura da pele. Conclusão: A condilectomia alta preveniu a progressão da deformidade facial, minimizando as sequelas funcionais e estéticas, o que visa a favorecer o tratamento das deformidades faciais através de correção ortognática em segundo momento cirúrgico.

A controversy with respect to occlusion

There are very little controversies on occlusion in healthy individuals, where centric relation is regarded as the criterion for assessing the present occlusion and also for establishing a new occlusal relationship between the upper and the lower jaws. On the other hand, the occlusal position in patients with deformed condyles still remains to be clarified. In this review, the effectiveness and limits of centric relation in these patients are discussed. In addition, the muscle induced occlusal positions, such as the muscular position and the terminal positions of habitual closing movements, are suggested as a substitution for centric relation. Finally, the importance of a stable intercuspal position, where the habitual closing movements terminate without any premature tooth contact, is emphasized.

Condylar hyperplasia: An updated review of the literature

Condylar hyperplasia (CH) is a rare disorder characterized by excessive bone growth that almost always presents unilaterally, resulting in facial asymmetry. Classification of the different types of CH can differ depending on the authors. Correct diagnosis is critical in determining the proper treatments and timing. This paper is a review of the recent literature on the epidemiology, etiology, diagnosis, classification, and surgical treatments of CH.

The microstructural and biomechanical development of the condylar bone: a review

BACKGROUND

Bone constantly strives for optimal architecture. Mandibular condyle, which is subjected to various mechanical loads forcing it to be highly adaptive, has a unique structure and a relatively high remodelling rate. Despite the eminent clinical relevance of mandibular condyle, literature on its structural and biomechanical development and on the mechanical role of its mineralized and non-mineralized bone components is scarce.

OBJECTIVE

The aim of the present review is to provide a brief introduction to basic bone mechanics and a synopsis of the growth and development of human mandibular condyle. Subsequently, the current ideas on the relationship between the structural and biomechanical properties of bone in general and of mandibular condyle in particular are reviewed. Finally, up-to-date knowledge from fundamental bone research will be blended with the current knowledge relevant to clinical dentistry, above all orthodontics.

METHODS

A comprehensive literature study was performed with an emphasis on recent and innovative work focusing on the interaction between microarchitectural and micromechanical properties of bone.

CONCLUSIONS

Mandibular condyle is a bone structure with a high bone turnover rate. Mechanical properties of mandibular condyle improve during adolescence and are optimal during adulthood. Local mineralization degree might not be a decisive determinant of the local bone tissue stiffness as was believed hitherto. Bone collagen and its cross links play a role in toughness and tensile strength of bone but not in its compressive properties. Clinical procedures might affect mandibular condyle, which is highly reactive to changes in its mechanical environment.

Management of patients with condylar hyperplasia: A diverse experience with 18 patients

PURPOSE

The purpose was to report the clinical experience with patients diagnosed with Condylar Hyperplasia (CH).

MATERIALS AND METHODS

Eighteen patients with CH underwent condylar growth assessment using clinical and radiographic examinations. Seven patients with suspected active condyles underwent single photo emission computed tomography (SPECT) examination. A total of patients with asymmetry and malocclusion were treated with orthognathic surgery. Three patients with intact occlusion; underwent inferior border osteotomy with nerve repositioning. All patients were followed up for 3 years without any complications.

CONCLUSION

There is great diversity in the clinical and radiographic presentation in cases with CH. Assessment of condylar growth activity is the cornerstone in managing these cases. After that each case has its own diverse treatment plan to achieve a satisfactory facial symmetry.

Posteroanterior cephalometric changes in subjects with temporomandibular joint disorders

OBJECTIVES

The aim of the study was to establish the changes in posteroanterior cephalometric variables in subjects with temporomandibular joint disorders (TMDs).

METHODS

Posteroanterior cephalograms of 61 subjects (age range 16-36.6 years, standard deviation 4.88 years) were used to determine cephalometric differences. Subjects were classified according to the Research Diagnostic Criteria for Temporomandibular Joint Disorders into three groups: unilateral TMD, bilateral TMD and no TMD. 14 linear and angular measurements were assessed on the posteroanterior cephalogram. For assessing facial asymmetry, the asymmetry index for bilateral measurements was calculated between the right and the left side. In cases with unilateral TMD, the asymmetry index was calculated using the difference between the unaffected and affected side. The differences among multiple groups were analysed using the one-way analysis of variance test and Scheffé post hoc test.

RESULTS

47 subjects were females (77%) and 14 were males (23%). 19 subjects had unilateral TMDs and 16 subjects had bilateral TMDs. The asymmetry index of the distance from the horizontal plane to the antegonion was higher in subjects with unilateral TMD than in patients with bilateral or no TMD (p < 0.05). Also, the asymmetry index of the distances from the vertical plane to the condyle (p = 0.05), gonion (Go) (p = 0.0004), antegonion (p = 0.002) and chin (Ch) (p = 0.02) was higher in subjects with unilateral TMDs. The asymmetry index of the O point-Go-Go' and O point-Ch-Ch' angles differed significantly in subjects with unilateral TMDs (p < 0.05).

CONCLUSIONS

Unilateral TMDs are associated with changes in posteroanterior cephalometric measurements. The assessment of posteroanterior cephalometric variables could be used as a key factor for evaluating the presence of TMDs.