Assessment of cross-sectional thickness of masseter, anterior temporalis and orbicularis oris muscles in OSMF patients and healthy controls by ultrasonography before and after treatment and correlation between the muscle thickness, muscle activity and maximum bite force

Abstract

Background: Oral submucous fibrosis (OSMF) is a premalignant condition of insidious onset which affects the oral mucosa, pharynx, and esophagus. The muscles of mastication are known to be affected in patients with OSMF resulting in limited mouth opening. Ultrasonography (USG) is a real time, non invasive imaging method of measuring and evaluating the muscle thickness. Previously, USG was primarily utilized in medical sciences, but it is currently being used extensively in both the medical and dentistry fields.
Objectives: The aim of the study is to evaluate the thickness of masticatory muscles muscle in OSMF patients before and after treatment and correlate it the muscle activity and the bite force and to compare with healthy controls.
Materials and Methods: It was a prospective case-control clinical study comprised 180 OSMF patients who were divided into four groups and 45 healthy individuals served as the control group. The OSMF individuals were injected with hyaluronidase 1,500 IU mixed in 1.5 ml of dexamethasone and 0.5 ml of lignocaine HCL
intralesionally twice a week for one month along with a basic physiotherapy regimen consisting of mouth exercises two times daily. The control subjects were given placebo capsules. The ultrasonographic muscle thickness was evaluated among the OSMF patients and control group before and after treatment and the results were correlated with muscle activity and the bite force.
Results: The results revealed that the thickness of masticatory muscles in OSMF patients was increased when
compared with healthy controls. Patients with OSMF did not show significant change in muscle thickness after treatment.
Conclusion: When compared with healthy controls, OSMF patients had higher increased muscular thickness and in OSMF patients, USG may help in determining the involvement of the mastication and facial expression muscles. It can also be used as a diagnostic tool to assess the treatment outcome of muscle activity in OSMF patients.