Background For the temporomandibular joint (TMJ) dry needling (DN) treatment is very useful, because of the reduced space of facial structures, that difficulty allow manual therapies. However, while it’s confirmed to be effective in relieving pain and tenderness, studies about its effects on healthy TMJ are lacking. To objectively assess the effects, Rehabilitative Ultrasound Imaging (RUSI) is a diagnostic technique accurate enough to show muscular changes and reliable to measure the cross-sectional area (CSA) dimensions of muscles of TMJ, even if performed by a novice.
Methods Each subject has received a DN treatment with dry needling to the trigger points (TrPDN) of temporalis and masseter muscles of one side of the face, depending on the group allocation. Masseter muscles thickness and CSA, temporalis muscle and TMJ articular disc thickness were evaluated at the beginning of the trial, after the treatment and after 30 days (follow-up). For masseter muscle, the panoramic view function of the sonograph Mindray M9 was used to entirely see the muscle in the same image. The study is a triple blind randomised controlled trial.
Results The basal characteristics of the two groups were similar in both groups: 2? y 2?, age 22,25±0,67 years, weight 75,75±1,77 kg, health 1,77±0,02 m and BMI 24,26±1,9. After DN the maximal mouth opening changed from 4,45±0,14 to 5±0,1 cm. The differences of the means between DN group and control group were: in TMJ thickness 0,03±0,04 (F 0,83; P 0,39); in temporal thickness 0,13±0,13 (F 0,24; P 0,64); in masseter thickness −0,07±0,05 (F 0,58; P 0,47); in masseter length −0,06±0,28 (F 0,63; P 0,46); in masseter perimeter −24,87±10,75 (F 2,09; P 0,19); and in masseter CSA 0,05±0,29 (F 0,84; P 0,39).
Conclusions DN doesn’t significantly influence morphological characteristics of the facial structures were founded. In fact, however TMJ articular disc and temporal thickness increased, masseter thickness decreased and the others measurements changed in different ways. This study has some limitations too, as the little dimensions of the sample, the short duration of the trial and few times of RUSI evaluations. Thus, these findings have to be considered as firsts results about DN treatment in healthy people and they should be integrated with those of further studies, to be successively used as a control group’s characteristics to compare with patients.