ABSTRACT
There has been a mistake, claimed and confirmed by all the authors of Vol 50(1), 2012, p. 1-9 issue, that first author should have been Il-Han Kim instead of Kwan-Tae Noh.
ABSTRACT
PURPOSE: The purpose of this study was to investigate the effects of a mouthguard on stress distribution under mandibular impact. MATERIALS AND METHODS: The FEM model of head consisted of skull, maxilla, mandible, articular disc, teeth, and mouthguard. The impact locations on mandible were gnathion, the center of inferior border, and the anterior edge of gonial angle. And the impact directions were vertical, oblique (45degrees), and horizontal. The impact load was 800 N for 0.1 sec. RESULTS: When vertical impact was applied, the similar stress and the distribution pattern was occurred without the relation of the mouthguard use (P>.05). The model with mouthguard was dispersed the stress to the teeth, the facial bone and the skull when the oblique (45degrees) impacts were happened. However, the stress was centralized on the teeth in the model without mouthguard (P<.05). The model with mouthguard was dispersed the stress to the teeth, the facial bone and the skull when the horizontal impacts was occurred. However, the stress was centralized on the teeth without mouthguard (P<.05). For all impact loads, stress concentrated on maxillary anterior teeth in model without mouthguard, on the contrary, the stress was low in the model with mouthguard and distributed broadly on maxillary anterior teeth, facial bone, and skull. CONCLUSION: The mouthguard was less effective at shock absorbing when vertical impact was added. However, it was approved that mouthguard absorbed the shock regarded to the oblique (45degrees) and horizontal impact by dispersing the shock to the broader areas and decreasing the stress.