Advancing Temporomandibular Joint Reconstruction: A Cadaveric Study on the Design of the Fourth Chondrocostal Joint Flap

BACKGROUND

The free fibula flap is the gold standard for reconstructing mandibular defects caused by trauma, tumors, dysplastic diseases, osteoradionecrosis, and atrophy. However, it has not yet been shown to be the ideal method for condylar reconstruction. This anatomical study proposes a surgically pragmatic approach to temporomandibular joint and condylar reconstruction by defining the vascularity of the chondrocostal joint.

METHODS

One fresh frozen and six fixed cadavers were dissected to assess the suitability of the 4th rib for the planned procedure. Bilateral internal thoracic vessels and branches surrounding chondrocostal joints were identified. The 4th chondrocostal joint flap was dissected with care to preserve the joint surface and perichondral vascularity. Digital calipers were used for precise measurements of maximal flap and pedicle length. The vascular anatomy was further explored in a fresh frozen cadaver through fluoroscopic imaging by radiopaque latex injection. The flap's suitability for temporomandibular joint reconstruction was tested by surgically removing the original temporomandibular joint from the cadaveric skull and positioning the chondrocostal joint flap in the resultant defect.

RESULTS

The dominant pedicle to the fourth chondrocostal joint was shown to be the perforators of the internal thoracic vessels. The mean pedicle length was 4.7 cm, which was sufficient to reach recipient vessels in the neck. The compatibility between the fourth chondrocostal joint and the glenoid fossa was confirmed.

CONCLUSION

This study demonstrates that the fourth chondrocostal joint flap is a promising free flap for temporomandibular joint and condylar reconstruction. It offers ideal pedicle positioning, length, and vascular size match at the anastomosis, making it a suitable technique for reconstructing the challenging temporomandibular region. This approach adds a new option to the reconstructive surgeon's armamentarium, addressing previous limitations in condylar reconstruction.

Hemifacial microsomia: a scoping review on progressive facial asymmetry due to mandibular deformity

PURPOSE

This scoping review explores various parameters of the mandible in progressive facial asymmetry (FA) in hemifacial microsomia (HFM) patients, highlighting its relationship with sex, population, and age group.

METHODS

The review was based on a comprehensive search of PubMed, EBSCOhost, and Web of Science. Eligible studies that met the inclusion criteria form part of the selection study. The included studies were appraised using screening and quantitative criteria of mixed-method appraisal tools. The authors utilised a pre-set data extraction form to obtain information from the included studies.

RESULTS

Eleven studies met the inclusion criteria. The mandible parameters used were angular measurements, chin point, ramal height, body length, and total length. There was no relationship between FA and sex in HFM patients in the included studies. Most of the studies were comprised of European participants (55%), followed by Americans (36%) and Chinese (9%). The age groups included in the selected studies were categorised as dentition age (18%), early-to-middle childhood (18%), and varied ages (64%). The data presented in this review only pertains to the anomalous characteristics recorded on the affected side in HFM patients. No concomitant control data was recorded in this review.

CONCLUSION

An assessment of the included studies revealed that FA does not increase with age in HFM. Hence, FA is non-progressive in HFM patients. This information is relevant to diagnosing and managing HFM patients. More reports are needed on the progression of FA in HFM patients.

Chewing Side Preference, Facial Asymmetry and Related Factors in the Northern Finland Birth Cohort 1986

OBJECTIVE

The aim of this study was to find out how the preferred chewing side (PCS) affects facial asymmetry, what kind of factors affect PCS, and whether there are differences in facial asymmetry between symmetrical and asymmetrical masticators.

MATERIAL AND METHODS

The study included 748 subjects (females n=452, males n=296) born in 1985-1986 in Northern Finland (Northern Finland Birth Cohort 1986, NFBC 1986). Subjects' faces were captured in facial 3D images with stereophotogrammetry technology, and they filled in a questionnaire concerning oral health. A comprehensive dental examination was done by a dentist. Subject´s chewing side preference was studied by chewing a piece of paraffin, cotton roll or parafilm. Asymmetry was measured from 3D images with different asymmetry measurements and facial landmarks.

RESULTS

Reduced number of teeth on contralateral side affects PCS (OR = 2.44 in the case of one tooth is missing). Being female increased the whole face and lower face symmetry (p values <0.001-0.824). Self-reported TMD pain has an effect on the sidedness of the chin; there is more pain in the larger side of the chin (OR = 9.45). Different chewing materials had no significant effect on the proportion of chewing sides.

CONCLUSIONS

Females have a more symmetrical face compared to males. PCS does not have a statistically significant effect on facial asymmetry, but the variable affecting PCS itself is extracted teeth.

Do pooled estimates from orthodontic meta-analyses change depending on the meta-analysis approach? A meta-epidemiological study

BACKGROUND

In meta-analyses involving a few trials, appropriate measures should be employed to assess between-study heterogeneity. When the number of studies is less than five and heterogeneity is evident, the Hartung and Knapp (HK) correction should be used. The aim of this study was to compare the reported estimates of published orthodontic meta-analyses with the pooled effect size estimates and prediction intervals (PI) calculated using eight heterogeneity estimators and corrected using the HK correction.

MATERIAL AND METHODS

Systematic reviews (SRs) published between 2017 and 2022 in four orthodontic journals and the Cochrane Database of Systematic Reviews with a meta-analysis of at least three studies were sourced. Study characteristics were extracted at the SR and the outcome/meta-analysis levels. All selected meta-analyses were re-analysed by fitting a random-effects model using eight different heterogeneity estimators, both with and without the HK correction. For each meta-analysis, the overall estimate, along with its standard error, the P-value, and the corresponding 95% confidence interval (CI), the between-study variance (tau2), the I2 statistic, and the PI were calculated.

RESULTS

One-hundred-six SRs were analysed. The most prevalent type of SR was non-Cochrane (95.3%), and the most used meta-analyses synthesis model was the random effect (83.0%). The median number of primary studies was 6 (interquartile range: 5, range: 3-45). The between-study variance was reported in most of the eligible meta-analyses (91.5%), but the type of heterogeneity estimator was reported in only one of them (0.9%). In 5 of 106 meta-analyses (4.7%), the HK correction was applied to adjust the CI of the pooled estimate. The percentage of statistically significant results, which became statistically non-significant, ranged from 16.7% to 25%, depending on the heterogeneity estimator. As the number of studies in a meta-analysis increased, the difference between corrected and uncorrected CIs reduced. Based on the PIs, more than half of the meta-analyses having statistically significant results are likely to change in the future, suggesting the result of the meta-analysis is not conclusive.

CONCLUSIONS

The statistical significance of pooled estimates from meta-analyses with at least three studies is sensitive to the HK correction, the heterogeneity variance estimator, and PIs. Clinicians should be aware of the clinical implications of not appropriately assessing the effect of the small number of studies and the between-study heterogeneity when interpreting results from meta-analyses.

Correlation of patients' demographics and clinical symptoms with temporomandibular disorders

OBJECTIVE

To investigate the correlation between basic characteristics and clinical features of patients with temporomandibular disorders (TMD).

METHODS

The R language statistical tool was used to analyze the clinical information of 500 TMD patients, i.e., age, sex, joint noises, mouth opening pattern, and pain symptoms, as well as the results of the mandibular push-back test. A pairwise correlation analysis of each clinical feature was carried out.

RESULTS

The highest incidence of TMD was observed in the age group of 20 to 30 years (240/500). Around 2/3 of the patients showed pain symptoms. Abnormal mouth opening patterns, joint noises, and temporomandibular joint synovitis (TMJS) were observed in 48.4, 65.4, and 34% of patients, respectively.

CONCLUSION

Joint click and the corrected deviation of the mouth opening pattern are signs of early-stage TMD, whereas limited mouth opening and TMJS are indicators of progressive stage and complicated TMD.

Temporomandibular joint articular disc position and shape in skeletal Class III

OBJECTIVE

To compare the position and shape of the temporomandibular joint (TMJ) articular disc among the sagittal and vertical skeletal patterns in Angle Class III, Class III subdivision malocclusion and normal occlusion. The null hypothesis was that there was no difference in disc position and shape in different (1) malocclusions and (2) skeletal patterns.

METHODS

This cross-sectional observational study evaluated 105 patients divided into 3 groups: Class III (33, 9.39 ± 1.96 years), Class III subdivision (45, 9.51 ± 1.59 years) and a normal occlusion (27, 10.24 ± 0.87 years) was included as healthy control. Severity of the maxilla-mandibular anteroposterior discrepancy and vertical facial pattern were determined using 2D cephalometry, and the position and shape of the articular discs were evaluated in magnetic resonance images. Statistical parametric and non-parametric tests and Kappa analysis for intra-observer and inter-observer assessment were used (p ≤ .05).

RESULTS

Significant between-group differences were found in articular disc position. In the normal occlusion group, all the articular discs were well positioned. In Class III and Class III subdivision, the discs were displaced in 30.3% and 12.2% of the TMJs, respectively. Sagittal and vertical skeletal patterns did not affect the findings significantly. The Class III subdivision malocclusion group is probably different from the other groups, showing 97.7% of biconcave discs in both TMJs.

CONCLUSION

The longitudinal follow-up of this sample becomes relevant as the two groups with malocclusion in the pre-peak phase of pubertal growth showed differences in the prevalence of displacement and form of the articular disc, with no association with their vertical facial characteristics.

Optimal Use of a Panoramic Radiograph as a Screening Tool for Condylar Resorption in Patients Undergoing Active Orthodontic Treatment: A Case Series

Condylar resorption of temporomandibular joint findings in the panoramic radiographs is an indication of bone resorption suggesting possible degenerative joint disease that warrants early screen and subsequent referral to a dedicated specialist. This case series reports three patients that underwent the active orthodontic treatment for the duration of approximately 24-36 months. The patients were asymptomatic at the initial examination. The clinical examination was negative for clicking; the range of motion on opening, lateral excursion, and protrusion was normal. Neither of these patients had a history of rheumatic disease or bruxism. During the later stages of orthodontic treatment, two of the three patients reported mild pain and clicking during mastication, which was also confirmed chairside on clinical evaluation. Patients were referred to the orofacial pain specialist, were they were prescribed specific medication for the symptoms, along with cognitive behavioral therapy, and were further evaluated for splint therapy. Panoramic radiographs taken before the start of the treatment, during the treatment and at the completion of the orthodontic treatments indicate the progression in the resorption of mandibular condyle in all three patients suggesting possible degeneration that warrants further investigation and therapy.