Effects of Mouth-opening Training on the Maximum Interincisal Opening

Effects of Mouth-opening Training With Follow-up Telephone Calls on the Maximum Interincisal Opening and Mandibular Function of Postoperative Oral Cancer Patients: A Randomized Clinical Trial

PURPOSE:The purpose of the study was to investigate the effect of mouth-opening training with follow-up telephone calls for reducing postoperative trismus in patients with oral cancer. METHODS:The study is a randomized clinical trial using repeated measures. Sixty-eight patients admitted at a general hospital in Taiwan for oral cancer surgery were recruited and randomly assigned to either the intervention or control group. All subjects were instructed to practice mouth-opening exercises three times a day every day for three months. Subjects in the intervention group received additional 6 follow-up phone calls to enhance mouth-opening exercise adherence. Data on maximum interincisal opening and mandibular function impairment were collected before surgery, at one-month, and three-months after discharge, using the TheraBite Range-of-Motion scale and Mandibular Function Impairment Questionnaire.

The purpose of the study was to investigate the effect of mouth-opening exercise training with follow-up telephone calls for preventing postoperative trismus in patients with oral cancer. The specific aims were to test the intervention effects on enhancing mouth-opening exercise practice, MIO, and mandibular function. We hypothesized that the intervention group would show 1) better adherence to mouth-opening exercises, 2) greater MIO, and 3) better mandibular function over time, compared to the control group. The study is a randomized clinical trial using repeated measures. A convenience sample of 68 oral cancer patients was recruited and randomly assigned to either the intervention or control group according to a list generated by the Random Allocation Software. Subjects in both groups received two 30-minute individual trainings on the mouth-opening exercises before discharge from the hospital. Subjects were instructed to practice the mouth-opening exercises three times a day, every day, for 12 weeks. Subjects in the intervention group received additional 6 follow-up phone calls (at 1, 2, 3, 4, 8 and 12-week after discharge) from the interventionist to enhance mouth-opening exercise adherence. Data on MIO and mandibular function impairment were collected before surgery, at one-month, and three-months after discharge, using the TheraBite Range-of-Motion scale and the Mandibular Function Impairment Questionnaire. The study was approved by the research ethics committee of the hospital where the data were collected. All statistical analyses were carried out using the SPSS statistical package version 20.0 (SPSS Inc., Chicago, IL, USA). Characteristics of the subjects were summarized by percentages, means, and standard deviations (SDs). Chi-squared tests or Fisher's exact tests and two independent samples t-tests were used to examine group baseline equivalency. Value changes of study outcomes (MIO and mandibular function impairment) and mouth-opening exercises performed from T1, T2, to T3 were expressed in two study groups. A general linear model was used to model these outcomes as a function of main group effect and main time effect. An interaction term (group difference by time) was added into each model to investigate the synergistic effect of the intervention with time. Both the stability analysis and the analysis of repeated relationships were performed by generalized estimation equations (GEE).

Subjects in the intervention group received two 30-minute individual trainings on the mouth-opening exercises before discharge from the hospital. Subjects were instructed to practice the mouth-opening exercises three times a day, every day, for 12 weeks. Subjects in the intervention group received additional 6 follow-up phone calls (at 1, 2, 3, 4, 8 and 12-week after discharge) from the interventionist to enhance mouth-opening exercise adherence.

Subjects in the control group also received two 30-minute individual trainings on the mouth-opening exercises before discharge from the hospital. Subjects were instructed to practice the mouth-opening exercises three times a day, every day, for 12 weeks.

Subjects in both groups received two 30-minute individual trainings on the mouth-opening exercises before discharge from the hospital. Subjects were instructed to practice the mouth-opening exercises three times a day, every day, for 12 weeks. Subjects in the intervention group received additional 6 follow-up phone calls (at 1, 2, 3, 4, 8 and 12-week after discharge) from the interventionist to enhance mouth-opening exercise adherence.

Subjects in both groups received two 30-minute individual trainings on the mouth-opening exercises before discharge from the hospital. Subjects were instructed to practice the mouth-opening exercises three times a day, every day, for 12 weeks.

The TheraBite® Range-of-Motion Scale was used to measure the maximum incisal opening (MIO), which is the maximal vertical distance between the edges of the incisors of the maxilla and the mandible. The TheraBite® Range-of-Motion Scale is a disposable paper measuring scale specially designed to measure a subject's mouth and jaw opening. The subject sits in an upright position with his mouth open wide. For measuring the vertical opening, the scale has a possible range of 5 to 70 mm, with the notch is placed on the lower incisor midline. The usual range of MIO is between 40 and 55 mm. Subjects with MIO <35 mm are considered to have trismus.

The MFIQ (Mandibular Function Impairment Questionnaire) was used to measure the extent of patients' mandibular function impairment. The questionnaire consists of 17 items, each of which targets a specific oral function impairment; including difficulties in social activity, speech, taking a large bite, chewing hard food, chewing soft food, work and/or daily activities, drinking, laughing, chewing resistant food, yawning, kissing, and eating different types of food. The subjects were asked to indicate how much difficulty they had with each activity or with eating each type of food using a 5-point Likert scale (0 = no difficulty, 4 = very difficult or impossible without help). The total score of the 17 items divided by 68 provides the scale score, with a possible range of 0 to 1. A higher score indicates greater severity of the mandibular function impairment. A score ≤ 0.3, between 0.3 and 0.6, and >0.6 indicates mild, moderate, and severe mandibular function impairment, respectively.

Inclusion Criteria: aged 18 years or older diagnosed with oral cancer scheduled for a primary curative oral cancer surgery able to communicate in Mandarin or Taiwanese obtained medical clearance from the patient's attending physician to participate in the study Exclusion Criteria: diagnosed with lip or tongue cancers which were less relevant to trismus had central incisors extracted during the surgery

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