The study of bruxism. The relationship among nocturnal teeth grinding, occlusal interference and psychological personality (author's transl)

Abstract

The purpose of this study was to investigate the relationship between noctural teeth grinding and occlusal interference. Furthermore, the personality of each subject was also investigated from the psychollogical aspect.The subject sample was composed of 25 nocturnal teeth grinders who recognized themselves as grinders. It included 7 males and 18 females [mean age 30.0 years range 19 to 49 years].The control sample was composed of 25 persons who were diagnosed in clinical examination as nonbruxer. It included 7 males and 18 females [mean age 26.1 years; range 19 to 63 years].To detect the prematurities and occlusal interferences in each occlusal position [centric occlusion, retruded contact position, lateral excursion, and protrusive excursion], occlusal examination was performed on all of the subjects and control persons with #30 sheet wax and occlusion test foil.Then the occlusal adjustment was done on 9 grinding patients for the purpose of eliminating all of the prematurities and occlusal interferences.The total grinding time overnight was measured with the “Grinding Monitoring System” which has been newly developed by the author. This system is composed of a portable casset tape recorder, small microphone, and acoustic senser which responds to grinding sound only. Each subject brought it back to their home and measured the amount of grinding for a week.To investigate personality, all of the subjects and control persons were examined with two types of questionire [Cornell Medical Index and Yatabe-Guilford test].The results were as follows;1) Only balancing side occlusal interference was significant [p<0.05]in incidence between the subject group and the control group.2) Any occlusal interferences which appeared unilaterally were not significant in incidence between the grinding group and the control group.3) The grinding time/hour of sleep during a week before the occlusal adjustment obtained from 12 subjects varied[mean time 15.15 sec/hour of sleep; range 1.53 to 71.02 sec/hour of sleep]. The varience of time of grinding between subjects was significant. And the varience between days was not significant.4) After the elimination of all prematurities and occlusal interferences, 2 out of g subjects significantly [p<0.05] reduced grinding time, but another 7 subjects did not show any changes in grinding time.5) The number of oppressive pain points on the masticatory muscles decreased to half by reason of the occlusal adjustment.6) The results of psychological test did not show significant difference in personality between the grinding subjects and the control persons.