The short‐term effect of stabilization‐type splints on the local asymmetry of masseter muscle sites

Abstract

Patients with temporomandibular disorders (TMD) may present with a cluster of joint and muscle disorders characterized primarily by pain, joint sounds and irregular or deviating jaw function. Maxillary stabilization-type splints represent the best standard therapy, so the purpose of this study was to evaluate changes in local cross-sectional dimensions (LCSD) of masseter muscle sites associated with short-term application of 'splint therapy' using the diagnostic approach of high-resolution gray-scale ultrasonography. The study included 29 patients who had signs and symptoms of temporomandibular disorders. Ultrasonographic investigation was performed with a linear (B-scan) 7.5 MHz small-part transducer to visualize the antero-superior, antero-inferior, medio-superior, medio-inferior, postero-superior and postero-inferior sites of the masseter muscle. To assess local muscle asymmetry patterns and to evaluate the respective effect of occluding splints, the 'absolute asymmetry index (AAI)' was used, with the mean maximum muscle diameter of the respective right and left sides calculated from three consecutive measurements before and after splint therapy. Comparing the pre-treatment with the 2-month follow-up values revealed a significant decrease in the overall mean asymmetry indices at the anterior (P < 0.01), medial (P < 0.05) and posterior (P < 0.05) muscle sites. There was no significant change in LCSDs at the various muscle sites (P > 0.05). The results of this study suggest stabilization-type splints to be effective in reducing local muscle asymmetries. Further studies are warranted to evaluate muscle-site specific effects in patient and non-patient groups and to relate these effects to pre-treatment variables like bite force, preferred chewing side, facial morphology and occlusion.

Ultrasonography as a tool for evaluating treatment of the masseter muscle in temporomandibular disorder patients with myofascial pain

“…Examinations were performed just before the beginning of treatment and within 1 week after the end of treatment using a Logiq 700 (GE Yokogawa Medical Systems, Tokyo, Japan) equipped with a 12-MHz-wide bandwidth linear active matrix transducer (6)(7)(8)(9)(10)(11)(12)(13)(14). Each subject was seated in an upright position with the head in a neutral position.…”

“…[9][10][11][12] Although US has been used to evaluate the effect of treatment, only the change in thickness has been assessed. 13,14 This study sought to clarify the ultrasonographic changes, including the internal appearance after splint therapy, and to investigate the use of this modality for evaluating the treatment effect on the masseter muscle of TMD patients with myofascial pain.…”

Alternatives to Radiation Investigations in Orthodontics

“…Generally speaking, conventional US serves well and is good for imaging muscles and soft tissues, but has poor acoustic impedance for bone. Muscles of mastication have been studied extensively with US which has been considered to be a valuable, precise technique for analysing muscle shapes [46][47][48][49] . Furthermore, US is superior to radiographs for soft tissue evaluation and definitely overcomes the radiation hazards.…”

Terapia com placa oclusal com e sem guias anteriores de desoclusão em pacientes com disfunção temporomandibular e zumbido subjetivo

“…Os autores verificaram melhora nos sintomas subjetivos gerais relatados pelos dois grupos, mas significantemente mais frequente no grupo experimental. Bertram et al (2001;2002) realizaram um estudos com pacientes com DTM em terapia com placa utilizando a ultra-sonografia de alta resolução para verificar as dimensões do músculo masseter. Segundo os autores seus resultados sugerem que a estabilização com placa oclusal é eficaz na redução das assimetrias musculares.…”

“…O uso da ultrassonografia também mostrou redução de assimetrias musculares com o uso da placa (BERTRAM, et al, 2001;2002 Uma das causas para a variabilidade de resposta à terapia com placa oclusal pode também estar relacionada ao grande número de sinais e sintomas associados à DTM e as diversas formas como essa condição pode se apresentar, com uma ampla combinação de sinais e sintomas.…”