J Korean Acad Prosthodont.  2012 Jan;50(1):1-9.

Finite element analysis of the effects of a mouthguard on stress distribution of facial bone and skull under mandibular impacts

• Noh KT
• Kim IH
• Roh HS
• Kim JY
• Woo YH
• Kwon KR
• Choi DG

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.

Keyword

Mouthguard; Finite element analysis; Impact; Stress distribution; Facial bone; Mandible

MeSH Terms

Facial Bones
Finite Element Analysis
Head
Mandible
Maxilla
Shock
Skull
Tooth

Figure

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  Fig. 1 Finite element model. A: Skull & Maxillae, B: Mandible, C: Teeth, D: Mouthguard.

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  Fig. 2 Impact location and direction.

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  Fig. 3 Measuring points and description. A: frontal view, B: lateral view, C: description.

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  Fig. 4 Impact force and time.

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  Fig. 5 Stress distribution on reference point of maxilla and skull according to with mouthguard (left bar) and without mouthguard (right bar) state for vertical force on A: gnathion, B: mandibular body, C: gonial angle.

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  Fig. 6 Stress distribution on reference point of maxilla and skull according to with mouthguard (left bar) and without mouthguard (right bar) state for oblique force on A: gnathion, B: mandibular body, C: gonial angle.

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  Fig. 7 Stress distribution on reference point of maxilla and skull according to with mouthguard (left bar) and without mouthguard (right bar) state for horizontal force on A: gnathion, B: mandibular body, C: gonial angle.

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