Changes in mandibular movement during chewing of different hardness foods

Abstract

In order to clarify the change in mandibular movement during chewing of foods with different hardness, 20 healthy subjects were asked to chew 3 types of gummy jellies (containing 6, 8, and 10% gelatin), and the masseter muscular activity and the mandibular movement were recorded. The indicators representing the muscular activity (integral value of masseter muscular activity), the mandibular movement (opening distance, masticatory width, cycle time, opening maximum velocity and closing maximum velocity), and the stability of masticatory movement were calculated, respectively, and compared among the three foods. The integral value of masseter muscular activity was smallest for the 6% gelatin and significantly increased in order as the content of gelatin increased to 8, 10%. The value of each indicator for the mandibular movement increased gradually as the food got harder. The value for all indicators was significantly larger for the 10 than the 6%. However, between the two foods, no significant change was observed for the several indicators. The mean ratio of the 10% gelatin to the 8% gelatin for the cycle time was extremely small, being 1.01, but was between the range of 0.89–1.07 showing aspects of changes within each individual. The other indicators showing small ratio were similar in this aspect. The parameters representing stability of movement showed the lowest values for the 8% gelatin. It was suggested that the hardness of food affected mandibular movement during mastication, but the movement changed variously according to the hardness and exerted muscular activities.

Masticatory behaviour and chewing difficulties in young adults with temporomandibular disorders

“…For this reason, the data obtained with the application of the JFLS protocol were particularly useful to demonstrate which conditions of mandibular limitation were more prominent in these patients recently affected by the disorder, which agrees with the findings of the clinical evaluation (OMES). Indeed, in order to bite and grind larger and more consistent foods, respectively, greater vertical movement, bite force and lateral excursion of the jaw are required . As described by Le Révérend et al, modifying food textures, even within the same "food family," would influence masticatory behaviour.…”

“…Although the symptoms may vary, they affect to a greater or lesser degree the choice, the intake and the pleasure of the food, so that the majority of TMD patients end up modifying their diet in function of this problem . As food texture can affect several aspects of the masticatory process, the evaluation of the perception of patients with TMD symptoms associated or not with occlusal alterations may help understanding how the disorder changes their chewing behaviour.…”

Perception and measurement of food texture: Solid foods

“…They found that jaw closing velocity was faster for soft jelly than for hard jelly, and found that lateral jaw excursion was enhanced when chewing hard gels. In the study on effects of compositional differences in cheese and cara- Komino and Shiga (2017) was much softer than winegums, and therefore, if the highest gelatin content 10% was increased more, then one might expect to observe the slowing down of the closing velocity. However, their main interest is limited to food samples which are normally eaten in Japan.…”

“…More recently, using soft (hardness 69.8 kPa), medium (109.6 kPa), and hard (150.2 kPa) gummy jellies with the same ingredients except gelatin content (6, 8, and 10% for soft, medium, and hard jelly, respectively) Komino and Shiga () reported the maximum closing velocity of 127.9 mm/s for soft jellies, 143.3 mm/s for medium jellies, and 151.7 mm/s for hard jellies. They found that lateral jaw excursion was enhanced when chewing hard gels where subjects could not manage only by vertical movement, which seems to be widely recognized.…”

“…They found that lateral jaw excursion was enhanced when chewing hard gels where subjects could not manage only by vertical movement, which seems to be widely recognized. Shiga commented that winegums made in Germany were too hard, and the hardest gummy jelly used in Komino and Shiga () was much softer than winegums, and therefore, if the highest gelatin content 10% was increased more, then one might expect to observe the slowing down of the closing velocity. However, their main interest is limited to food samples which are normally eaten in Japan.…”