Quantitative bone imaging biomarkers to diagnose temporomandibular joint osteoarthritis.

Bone degradation of the condylar surface is seen in temporomandibular joint osteoarthritis (TMJ OA); however, the initial changes occur in the subchondral bone. This cross-sectional study was performed to evaluate 23 subchondral bone imaging biomarkers for TMJ OA. The sample consisted of high-resolution cone beam computed tomography scans of 84 subjects, divided into two groups: TMJ OA (45 patients with TMJ OA) and control (39 asymptomatic subjects). Six regions of each mandibular condyle scan were extracted for computation of five bone morphometric and 18 grey-level texture-based variables. The groups were compared using the Mann-Whitney U-test, and the receiver operating characteristics (ROC) curve was determined for each variable that showed a statically significance difference. The results showed statistically significant differences in the subchondral bone microstructure in the lateral and central condylar regions between the control and TMJ OA groups (P< 0.05). The area under the ROC curve (AUC) for these variables was between 0.620 and 0.710. In conclusion, 13 imaging bone biomarkers presented an acceptable diagnostic performance for the diagnosis of TMJ OA, indicating that the texture and geometry of the subchondral bone microarchitecture may be useful for quantitative grading of the disease.

Evaluation of the cytotoxicity of latex and non-latex orthodontic separating elastics.

OBJECTIVE: To test the hypothesis that a difference in cytotoxicity exists between latex and non-latex orthodontic separating elastics. MATERIAL AND METHODS: Five intra-oral separating elastics from different manufactures (four latex and one non-latex) were divided into five groups of 15 elastics each: Group MA (non-latex elastics, Masel), Group MO (natural latex, Morelli), Group DE (natural latex, Dentaurum), Group TP (natural latex, TP Orthodontics) and Group UN (natural latex, Unitek). The cytotoxicity assay was performed using cell cultures (epithelial HEp-2 cells originating from human laryngeal carcinoma) that were submitted to the cell viability test with neutral red (dye-uptake) at 24, 48, 72 and 168 h. Analysis of variance (anova) with multiple comparisons and Tukey's test were employed (p < 0.05). RESULTS: The results showed no statistically significant differences between groups MA, DE, TP and UN in relation to Group CC (cell control) for experimental times of 24, 48 and 168 h (p > 0.05). Morelli, Dentaurum, TP Orthodontics and Unitek elastics induced a great amount of cell lyses at 72 h. CONCLUSION: One can demonstrate that the Masel elastic induced less cell lysis compared with other elastics, but all trademarks were found to be clinically biocompatible. CLINICAL RELEVANCE: Separating orthodontic elastics are used in the interdental subgingival region with the aim to separate the teeth for placement of orthodontic bands. However, latex has been known to cause allergy. As these materials are widely used in clinical orthodontics, care regarding the cytotoxicity of orthodontic elastics should be taken. Thus, clinically proven biocompatible materials should be acquired whenever possible.