The aim of this study was to assess the best timing to perform arthrocentesis in the management of temporomandibular disorders with regards to conservative treatment. A systematic search based on PRISMA guidelines, including a computer search with specific keywords, reference list search, and manual search was done. Relevant articles were selected after 3 search rounds for final review based on 6 predefined inclusion criteria, followed by a round of critical appraisal. Eleven publications, including 5 randomized controlled trials and 6 prospective clinical studies informed this review. The studies were divided into 3 groups based on the timing of arthrocentesis: 1). Arthrocentesis as the initial treatment, 2). Early arthrocentesis, and 3). Late arthrocentesis. Meta-analyses compared the efficacy of improvement in mouth opening and pain reduction in the 3 groups. The results were statistically significant and favoured early arthrocentesis, followed by late arthrocentesis in terms of both improvements in mouth opening and pain reduction. All 3 groups showed improvement in mouth opening and pain reduction. We conclude that early arthrocentesis may be able to produce the best clinical results, while arthrocentesis before attempting conservative treatment may produce less favourable outcomes.

Abstract: Background: Pain management is one of the main parts of treatments for Temporomandibular Disorders (TMDs). However, there is still a lack of high-quality evidence that compare the overall effects of these non-surgical treatments. The objective of this systematic review is to identify the most potential treatment protocol in dealing with pain caused by TMDs through a mixed comparison of interventions based on network meta-analysis. Methods: A systematic review and network meta-analysis of studies identified by searching PubMed, Embase, Medline, Ovid, and CINAHL. All the included studies should have characteristics that: (1) participants with TMDs of any age; (2) non-surgical treatments; (3) score of Visual Analog Scale (VAS) as the outcome measure; (4) randomized controlled trials. The Cochrane Bias Assessment Toll was used to assess the bias, the CINeMA website was applied to rate the confidence of evidence, and ADDIS software was used to conduct the network meta-analysis. Results: 46 studies were included in this review. The agreement between authors reached a kappa value of 0.78. The results of the network meta-analysis showed that wearable therapy devices are more likely to be the best choice for reducing the pain of patients with myogenic TMDs, whereas a combination of platelet-rich plasma injection and wearable therapy devices is more likely to be the best choice for reducing the pain in a long term after treatment for patients with mix-type TMDs. Moreover, the application of therapy equipment has the most potential in reducing pain in a long term after treatment for patients with articular TMDs. Discussion: Wearable devices have a great potential for pain syndrome caused by TMDs, the mechanism might come from a biomechanical perspective. However, the overall confidence rating of evidence is low. Studies with high quality are still needed in the future. Other: The PROSPERO Registration Number of this systematic review is CRD42021253442.

Objectives: The present study was performed to compare between two different fixation techniques and evaluate the histopathological changes which occur in temporomandibular joint (TMJ) of the dogs after surgically induced unilateral subcondylar fracture. Methods: Twenty- One healthy beagle male dogs with a mean age of 30 months were used in the present study. One of these animals was sacrificed to study the normal histology of the dog TMJ. The rest of the animals (20 animals) were operated on to induce a displaced unilateral subcondylar fracture then, the animals were randomly equally divided into 2 groups. After surgery, 5 dogs of each group were sacrificed at 2 months after surgery (Short-Term), while the remaining 5 were sacrificed at 4 months after surgery (Long-Term). The heads were separated and fixed, oscillating saw was used to articulate the entire TMJ. Specimens were decalcified, then the specimens were washed, grossed and sectioned in a sagittal plane. Tissue sections of 4 um thick were cut and stained with Hematoxylin and Eosin to be studied microscopically. Results: In group I animals, at 2 months after surgery, there was a marked hypertrophy of the articular fibrous covering of the condylar head, while at 4 months after surgery, the articular fibrous covering appeared thinner than normal, with marked decrease in thickness of the articular cartilage layer. In group II, at 2 months after plate insertion, the articular fibrous covering became hypertrophic, and the articular cartilage was markedly reduced but it was of a uniform thickness, while at 4 months after subcondylar fracture and plate fixation, no significant changes could be detected either in thickness or structure of the articular fibrous covering. Conclusion: Based on this study, it is obvious that the plate fixation group gave the most favorable results, when compared with maxillomandibular fixation (MMF) group.