골절정복겸자가 하악골 골절정복에 미치는 효과에 관한 광탄성 연구

A PHOTOELASTIC STUDY ON EFFECTS OF BONE REDUCTION FORCEPS ON MANDIBULAR FRACTURE REDUCTION

The purpose of this study was to evaluate the stress patterns within fractured mandibles generated by reduction forceps and to determine the optimal position of the reduction forcep. Twenty-seven mandibular models were fabricated using a photoelastic resin. Each of the three sets of mandible models prepared was osteotomized according to one of three different fracture types(symphysis, parasymphysis and body fractures). After reducing the cut segments, a reduction forcep was placed into different engagement holes to compress the segments. Photoelastic stress analysis was used to visualize the stress patterns within the fractured mandiblular models generated by the reduction forcep. In the case of symphysis or parasymphysis fractures, an optimum distribution of stress over the fracture site was achieved when placing the reduction forcep more than 12.5㎜ on either side of the fracture line between the midway level bisecting the mandible and 5㎜ below the level. In the case of body fractures, optimum stress distribution was achieved when the reduction forcep was placed more than 15㎜ from the fracture line on the midway level. In conclusion, a correct use of reduction forceps helps to provide a precise threedimensional reduction for mandibular fractures.