Influence of Clenching Intensity on Bite Force Balance, Occlusal Contact Area, and Average Bite Pressure

Abstract

It has been difficult for investigators to simultaneously and reliably evaluate bite force in the intercuspal position with the area and location of occlusal contacts. This study was designed to investigate the variations in these parameters with respect to two factors: three levels of clenching and the preferred chewing side. Human subjects with normal occlusion were examined with a recently developed system (Dental Prescale Occluzer, Fuji Film, Tokyo, Japan). The three levels of clenching intensity were assessed by masseteric EMG activity and included the maximum voluntary contraction, and 30% and 60% of the maximum. The results indicated that the bite force and occlusal contact area on the whole dental arch increased with clenching intensity. In contrast, the average bite pressure, obtained by dividing the bite force by the contact area, remained unchanged regardless of the clenching intensity. As the clenching intensity increased, the medio-lateral position of the bite force balancing point shifted significantly (P<0.01) from the preferred chewing side toward the midline. The antero-posterior position remained stable in a range between the distal third of the first molar and the mesial third of the second molar. The bite force and occlusal contact area, which were mainly on the molars, increased with the clenching intensity, whereas the proportions of these two variables on each upper tooth usually did not change significantly. The exception was the second molar on the non-preferred chewing side. When comparisons were made between pairs of specific upper teeth of same name, usually no significant difference was found in bite force or occlusal contact area, regardless of the clenching level. Again, the exception to this observation was the second molar on the preferred chewing side, which had a larger area at the 30% clenching level. The results in normal subjects suggest that as the clenching intensity increases in the intercuspal position, the bite force adjusts to a position where it is well-balanced. This adjustment may prevent damage and overload to the teeth and temporomandibular joints.

Long-term stability of an injection-molded zirconia bone-level implant: A testing protocol considering aging kinetics and dynamic fatigue

“…(7)). Since fracture load before and after the applied artificial aging procedure represents the most relevant factor for predicting mechanical reliability, it should be considered the primary outcome and comprise a "safety buffer" of at least 50% as when compared to maximum in vivo loading forces on implants or teeth (maximum voluntary contraction or greatest clenching strength measured in clinical trials was reported to be in the range of 350-400 N in the molar region [41][42][43]). This results in a required fracture load of at least 600 N. For "standard" pre-clinical evaluation of mechanical long-term reliability (as it should be mandatorily required), phase transformation measurements might be considered supplementary for fault tracing or when comparing different materials or processing technologies.…”

Accuracy of contacts calculated from 3D images of occlusal surfaces

“…7-11 Contact information from these systems is limited because their sensors could interfere with and alter occlusion, contacts are not directly related to occlusal anatomy, and the results are two-dimensional. 12,13 Addition silicones are frequently used to record contacts because of their low viscosity, accuracy, and stability. The flow properties and uniform distribution of the materials across occlusal surfaces of teeth ensure minimal interference on closure.…”

Application of "Prescale" as an Aid to Clinical Diagnosis in Orthodontics

“…This system is now being used in various fields of dental research, particularly by Japanese researchers [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][22][23][24][25][26][27][28][29][30][31][32][33] . These studies have suggested that this system might help evaluating masticatory function and could be applicable to general dental clinical work.…”