Increased Risk of Temporomandibular Joint Closed Lock: A Case-Control Study of ANKH Polymorphisms

Objectives: This study aimed to carry out a histological examination of the temporomandibular joint (TMJ) in ank mutant mice and to identify polymorphisms of the human ANKH gene in order to establish the relationship between the type of temporomandibular disorders (TMD) and ANKH polymorphisms.\ud \ud Materials and Methods: Specimens from the TMJ of ank mutant and wild-type mice were inspected with a haematoxylin and eosin staining method. A sample of 55 TMD patients were selected. Each was examined with standard clinical procedures and genotyping techniques.\ud \ud Results: The major histological finding in ank mutant mice was joint space narrowing. Within TMD patients, closed lock was more prevalent among ANKH-OR homozygotes (p = 0.011, OR = 7.7, 95% CI 1.6–36.5) and the elder (p = 0.005, OR = 2.4, 95% CI 1.3–4.3).\ud \ud Conclusions: Fibrous ankylosis was identified in the TMJ of ank mutant mice. In the human sample, ANKH-OR polymorphism was found to be a genetic marker associated with TMJ closed lock. Future investigations correlating genetic polymorphism to TMD are indicated

Effect of chewing upon disc reduction in the temporomandibular joint

Aims: To test whether an intensive chewing exercise influences the moment of disc reduction in subjects with or without reports of intermittent locking of the jaw. Methods: This experimental study included 15 subjects with a reducing anteriorly displaced disc (ADD) and with symptoms of intermittent locking and 15 subjects with a reducing ADD without such symptoms. The moment of disc reduction (MDR), quantified using mandibular movement recordings, was recorded at baseline, and after maximally 60 minutes of chewing. Thereafter, MDR was recorded again after 20 minutes of rest, and if necessary after 72 hours, in order to document return of MDR to baseline values. Results: In subjects without intermittent locking, the MDR after chewing was not different from baseline (P = .25). However, in the subjects with intermittent locking, the MDR value had increased significantly after chewing (P = .008); two subjects showed a later moment of disc reduction, and four showed a temporary loss of disc reduction. Conclusion: While intensive chewing did not influence disc reduction in subjects without intermittent locking, it caused a delay or even hampered disc reduction in approximately half of the subjects reporting intermittent locking

Evaluation of the research diagnostic criteria for temporomandibular disorders for the recognition of an anterior disc displacement with reduction

The aim of this Focus Article is to review critically the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) for the recognition of an anterior disc displacement with reduction (ADDR) in the temporomandibular joint (TMJ). This evaluation is based upon the experience gained through the careful analysis of mandibular movement recordings of hundreds of patients and controls with or without an ADDR. Clinically, it is a challenge to discriminate between the two most prevalent internal derangements of the TMJ: ADDR and symptomatic hypermobility. It is due to the very nature of these derangements that they both show clicking on opening and closing (reciprocal clicking), making reciprocal clicking not a distinguishing feature between these disorders. However, there is a difference in timing of their opening and closing clicks. Unfortunately, it is not feasible to use this difference in timing clinically to distinguish between the two internal derangements, because it is the amount of mouth opening at the time of the clicking which is clinically noted, not the condylar translation. Two other criteria proposed by the RDC/TMD for the recognition of an ADDR are the 5-mm difference in mouth opening at the time of the opening and closing clicks, and the detection of joint sounds on protrusion or laterotrusion in case of non?reciprocal clicking. These, however, run the risk of false-positive or negative results and therefore have no great diagnostic value. Instead, it is recommended that the elimination of clicking on protrusive opening and closing be examined in order to distinguish ADDRs from symptomatic hypermobility

Evaluation of the research diagnostic criteria for temporomandibular disorders for the recognition of an anterior disc displacement with reduction

The aim of this Focus Article is to review critically the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) for the recognition of an anterior disc displacement with reduction (ADDR) in the temporomandibular joint (TMJ). This evaluation is based upon the experience gained through the careful analysis of mandibular movement recordings of hundreds of patients and controls with or without an ADDR. Clinically, it is a challenge to discriminate between the two most prevalent internal derangements of the TMJ: ADDR and symptomatic hypermobility. It is due to the very nature of these derangements that they both show clicking on opening and closing (reciprocal clicking), making reciprocal clicking not a distinguishing feature between these disorders. However, there is a difference in timing of their opening and closing clicks. Unfortunately, it is not feasible to use this difference in timing clinically to distinguish between the two internal derangements, because it is the amount of mouth opening at the time of the clicking which is clinically noted, not the condylar translation. Two other criteria proposed by the RDC/TMD for the recognition of an ADDR are the 5-mm difference in mouth opening at the time of the opening and closing clicks, and the detection of joint sounds on protrusion or laterotrusion in case of non?reciprocal clicking. These, however, run the risk of false-positive or negative results and therefore have no great diagnostic value. Instead, it is recommended that the elimination of clicking on protrusive opening and closing be examined in order to distinguish ADDRs from symptomatic hypermobility

Masticatory muscle stretching for the management of sleep bruxism: A randomised controlled trial

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