Analysis of mandibular motion following unilateral and bilateral alloplastic TMJ reconstruction.

The purpose of this study was to analyse the masticatory patterns and range of motion (maximal incisal opening (MIO), protrusion and lateral excursion) in patients who have had unilateral and bilateral temporomandibular joint (TMJ) replacement with an alloplastic prosthesis, and compare them to each other and to normal controls. Mandibular motion was examined in 18 patients, who had undergone alloplastic TMJ reconstruction, 13 with a bilateral prosthesis and 5 with a unilateral prosthesis, and in 13 normal controls. A statistically significant difference (P<0.01) for MIO and maximum lateral excursion was observed between the bilateral group and the control group. Maximum protrusion was only statistically significantly different (P<0.05) between the bilateral group and the control group. For the unilateral group, a statistically significant difference (P<0.01) was seen only with maximum contralateral excursion when compared with controls. No statistically significant difference existed in MIO and protrusion between the unilateral and bilateral groups. Even though maximum ipsilateral lateral excursion was greater for the unilateral group than either left or right maximum lateral excursion by the bilateral group, this difference was not statistically significant. This study provided an in vivo analysis of mandibular motion following alloplastic TMJ reconstruction.