Masticatory mechanosensitivity, mouth opening and impact of headache in subjects with a history of orthodontics use: a cross-sectional study.

BACKGROUND: The correlation between orthodontics and the development of signs and symptoms of temporomandibular disorders (TMD) is a major concern in the physical rehabilitation field. AIM: The aim of the study was to observe whether subjects with a history of orthodontics use show differences from subjects who have never used orthodontics in: 1) masseter and temporalis muscle mechanosensitivity; 2) maximal vertical mouth opening (VMO); and 3) the impact of headache on their quality of life. DESIGN: Cross-sectional study. SETTING: The study was carried out in the Faculty of Nursing, Physiotherapy and Podiatry of the University of Sevilla, Spain. POPULATION: All participants were pre graduate students from the University of Sevilla, Spain. The final sample comprised 65 subjects (N.=65) with a mean age of 21 ± 2.46 years (18-29) divided into two groups; orthodontics group (N.=31) and non-orthodontics group (N.=34). METHODS: All students followed the same testing protocol. Measurements were taken of the pressure pain threshold (PPT) in two locations of the masseter (M1, M2) and temporalis (T1, T2) muscles, the maximal VMO, and the incidence of headache (Headache Impact Test-6; HIT-6, Spanish version). RESULTS: The measured values of the masticatory muscle PPTs were lower in the non-orthodontics group. Besides, the maximal VMO and HIT-6 scores were better in the orthodontics group. Nevertheless, none of these intergroup differences were statistically significant (ANOVA test): (M1 P=0.790); (M2 P=0.329); (T1 P=0.249); (T2 P=0.440); (HIT-6 P=0.443); (VMO P=0.626). CONCLUSION: A previous history of orthodontics use does not seem to lead to any greater sensitivity of the masticatory muscles, limitations of vertical mouth opening, or greater impact of headache on the subject's quality of life. CLINICAL REHABILITATION IMPACT: There is no evidence enough to support either a positive or negative correlation between orthodontics and signs and symptoms of TMD. Pain is a subjective perception and it is influenced by several factors. It remains uncertain if the use of orthodontics might be one of them.

Short-term changes in median nerve neural tension after a suboccipital muscle inhibition technique in subjects with cervical whiplash: a randomised controlled trial.

OBJECTIVES: To assess the immediate effect of a suboccipital muscle inhibition (SMI) technique on: (a) neck pain, (b) elbow extension range of motion during the upper limb neurodynamic test of the median nerve (ULNT-1), and (c) grip strength in subjects with cervical whiplash; and determine the relationships between key variables. DESIGN: Randomised, single-blind, controlled clinical trial. SETTING: Faculty of Nursing, Physiotherapy and Podiatry, University of Seville, Spain. PARTICIPANTS: Forty subjects {mean age 34 years [standard deviation (SD) 3.6]} with Grade I or II cervical whiplash and a positive response to the ULNT-1 were recruited and distributed into two study groups: intervention group (IG) (n=20) and control group (CG) (n=20). INTERVENTIONS: The IG underwent the SMI technique for 4minutes and the CG received a sham (placebo) intervention. Measures were collected immediately after the intervention. MAIN OUTCOME MEASURES: The primary outcome was elbow range of motion during the ULNT-1, measured with a goniometer. The secondary outcomes were self-perceived neck pain (visual analogue scale) and free-pain grip strength, measured with a digital dynamometer. RESULTS: The mean baseline elbow range of motion was 116.0° (SD 10.2) for the CG and 130.1° (SD 7.8) for the IG. The within-group comparison found a significant difference in elbow range of motion for the IG [mean difference -15.4°, 95% confidence interval (CI) -20.1 to -10.6; P=0.01], but not for the CG (mean difference -4.9°, 95% CI -11.8 to 2.0; P=0.15). In the between-group comparison, the difference in elbow range of motion was significant (mean difference -10.5°, 95% CI -18.6 to -2.3; P=0.013), but the differences in grip strength (P=0.06) and neck pain (P=0.38) were not significant. CONCLUSION: The SMI technique has an immediate positive effect on elbow extension in the ULNT-1. No immediate effects on self-perceived cervical pain or grip strength were observed.