A two-colour chewing gum test for assessing masticatory efficiency

Objective: The aim of this study was to investigate different assessment methods of a two-colour chewing gum test for masticatory efficiency to determine its validity for research and clinical purposes. Material and Methods: Twenty adult volunteers, 11 women and 9 men (mean age of 27.5 years), participated in this study. All participants perceived their masticatory efficiency as normal. The task was to chew 5 samples of a two-colour chewing gum for 5, 10, 20, 30 and 50 cycles, respectively. Maximum bite force was measured. All samples were assessed twice by two independent operators both, as “bolus” and after flattening to 1 mm thick “wafers”. The latter were scanned and the unmixed pixels counted using Adobe Photoshop Elements® to calculate the ratio of unmixed colour to the total surface. Results: Digital image processing confirmed a significant correlation between colour mixing and chewing duration (p<0.001). Subjective assessment proved less accurate with fair to substantial intra-examiner agreement for “bolus” (0.20 Supported by the Suisse National Science Foundation, grant no 3200B0-108239.