MMPs in tissues retrieved during surgery from patients with TMJ disorders relate to pain more than to radiological damage score

Temporomandibular joint degeneration arises spontaneously in STR/ort mice and is prevented by targeted aggrecanase inhibition

OBJECTIVE

Temporomandibular joint osteoarthritis (TMJ-OA) is painful and causes masticatory dysfunction, but current treatment is limited to symptom relief due to an incomplete appreciation of aetiology. Herein, we develop morphological and histological methods for quantitative evaluation of TMJ-OA severity and examine whether STR/Ort mice, which are genetically predisposed to spontaneous knee OA, exhibit protection against TMJ-OA upon genetic gain-of-function modification of an aggrecanase-selective mutant of tissue inhibitor of metalloproteinase (TIMP)-3.

DESIGN

We established morphological changes in mandibular condylar head adapted from human TMJ-OA criteria, and developed and verified the utility of TMJ-OA histological damage scoring adapted from the OARSI system. Mutant TIMP3 containing an extra alanine at the N-Terminus ([-1A] TIMP-3 was overexpressed in STR/Ort and CBA mice. Morphological changes in mandibular condyle and TMJ cartilage degradation were evaluated and quantified using micro-CT and histology in mice aged 10, 20 and 40 weeks.

RESULTS

Whilst no evidence of TMJ-OA was observed in STR/Ort mice aged 10 weeks, bone erosion and osteophyte formation appeared in the mandibular condyle by 20 weeks, with remarkable deformity and bone resorption at 40 weeks in STR/Ort, but not the parental CBA strain. TMJ-OA was less severe in 40 week-old [-1A]TIMP-3 overexpressing STR/Ort and CBA compared to wild-type mice.

CONCLUSIONS

Using our new mouse TMJ-OA scoring system we have found that OA affects joints other than the knee in the STR/Ort strain. Genetic gain-of-function modification of STR/Ort mice with an aggrecanase-selective mutant of tissue inhibitor of metalloproteinase (TIMP)-3 also affords in vivo chondroprotection against this TMJ-OA.

Association between circulating inflammatory proteins and temporomandibular disorders: insight from a two-sample Mendelian randomization analysis

BACKGROUND

Past studies have indicated links between specific inflammatory proteins in the bloodstream and temporomandibular disorders (TMDs). Nonetheless, there remains the need for further solid research pinpointing the exact causes behind these associations. This Mendelian randomization (MR) study aims to examine the association between 91 circulating inflammatory proteins and TMDs.

METHODOLOGY

The most comprehensive genome-wide association studies available for circulating inflammatory proteins and TMDs was used in this two-sample MR analysis. The association between genetic predispositions to TMDs and levels of circulating inflammatory proteins was explored by various methods, including inverse variance weighted, MR-Egger, weighted median, simple mode, weighted mode, and MR-PRESSO techniques. To evaluate the reliability of these findings, sensitivity analyses such as Cochran's Q test, the MR-Egger intercept test, and a leave-one-out approach were conducted.

RESULTS

Findings indicated significant links between lower levels of circulating CCL4 (odds ratio, OR: 0.9241, 95% confidence interval, CI: 0.8679-0.984, p=0.0138), IL-20 (OR: 0.8615, 95%CI: 0.7566-0.9808, p=0.0243), and TWEAK (OR: 0.8702, 95%CI: 0.7634-0.992, p=0.0375) and an increased risk of TMDs, according to the inverse variance weighted method. Conversely, a higher level of S100A12 in the blood stream was associated with an increased risk of TMDs (OR: 1.1368, 95%CI: 1.0134-1.2752, p=0.0286). Sensitivity analyses confirmed the stability of these outcomes.

CONCLUSION

This study suggests that reduced levels of CCL4, IL-20, and TWEAK are associated with a higher risk of TMDs, alongside an increased risk of TMDs connected to elevated levels of S100A12.

Efficacy of Arthrocentesis and Anterior Repositioning Splints in Treatment of Internal Derangement of TMJ: A Prospective Clinical Study

The aim of this study is to assess the efficacy of double puncture arthrocentesis and anterior repositioning splints in the treatment of internal derangement of temporomandibular joint. 35 patients with mean age of 36.6 years ± 10.2 years diagnosed with unilateral TMD who fell into Wilkes stage 2 and disc displacement with reduction with intermittent locking described by RDC/TMD were treated with Nitzan's double puncture arthrocentesis and were given a anterior repositioning hard splint. The parameters following parameters were assessed at intervals of 1 week, 2 weeks, 1 month, 3 months and 6 months: pain, maximum inter-incisal mouth opening, Joint noise/click. Statistically significant (p < 0.001) improvements were seen at all recorded intervals in all observed parameters. Simultaneous arthrocentesis and anterior repositioning splint therapy is effective in alleviating pain and improving mouth opening without discomfort in patients with unilateral painful TMD showing disc displacement with reduction with intermittent locking.