Effects of Sustained Jaw Opening on the Masseter Muscle in En­do­don­tic Patients in Whom Rubber Dam Dry Field Technique Was Used

Abstract

Purpose: The effects of sustained jaw opening during dental treatment on the masseter muscle and stomatognathic functions are unknown. The aim of this study was to investigate the effects of sustained jaw opening on masseter muscle pain and jaw-opening function in endodontic patients in whom rubber dam dry field technique was used.
Methods: A total of 41 endodontic patients in whom rubber dam dry field technique was used participated in this study. Before and after rubber dam dry field technique, all participants were assessed for pain free opening, maximum unassisted opening, maximum assisted opening, and palpation of both masseter muscles according to the Diagnostic Criteria for Temporomandibular Disorders （DC/TMD）.
Results: Pain free opening and maximum unassisted opening after rubber dam dry field technique were significantly higher than before rubber dam dry field technique. Although masseter muscle pain was not detected in four patients （4/41participants; 10％） on palpation before rubber dam dry field technique, masseter muscle pain was detected in these patients on palpation after rubber dam dry field technique. In seven participants （7/41participants; 17％）, the masseter muscle pain on palpation disappeared due to the sustained jaw opening associated with rubber dam dry field technique. Thirty participants （30/41participants; 73％） did not change the masseter muscle pain on palpation between before and after rubber dam dry field technique.
Conclusions: These findings may suggest that sustained jaw opening during dental treatment contribute to extension exercise on masseter muscles and change the pain sensation on the masseter muscle pain.