关键词: 第一磨牙, 正中咬合, 咀嚼, 咬合力, (牙合)不平衡指数

Abstract: Objective To compare the occlusal contact characteristics of two different restoration methods of implant crown and removable partial denture while one single first molar was missing. Methods 15 adults with one single first molar missing were selected as the experimental group, 15 normal dentition adults were selected as the control group. Each patient of the experimental group was restored with implant crown and removable partial denture, then the occlusal contact characteristics (total occlusal force, total contact area, asymmetry index of occlusal force, chewing duration and OT/DT ratio) of each patient of experimental group under three different states (no repair, removable partial denture and implant crown ) werecomparedwith the control group. Each subject was detected with the TeeTester occlusal analyzer during centric occlusion and mastication movement. And SPSS 24 software was used for statistical analysis. Results During centric occlusion,the total occlusal force, total contact area and asymmetry index of occlusal force of the patients with no repair were （48.76±12.82）kg，（317.59±58.47）mm2 and （24.78±7.40）,the results of patients with removable partial denture were （54.36±10.59）kg，（355.81±77.43）mm2，（18.29±8.42）,the results of patients with implant crown were （61.94±12.36）kg,（398.17±83.86）mm2,（17.80±6.69）.During mastication movement, the total occlusal force, total contact area, asymmetry index of occlusal force, chewing duration and T0/Td ratio of the patients with implant crown were （52.14±16.53）kg,（348.08±81.76）mm2,（15.69±9.16）,（0.4072±0.10）s and （1.718±0.26）.The statistical analysis showed no significant difference in occlusal contact characteristics in implant crown, removable partial denture and the control group, but there was significant difference between the patients with no repair and other groups. There was no significant difference in chewing duration and the T0/Td ratio of all groups. Conclusion In the aspect of total occlusal force and contact area, implant crown is better than removable partial denture, closer to natural dentition, and obviously better than no restoration. The total bite force and total contact area during centric occlusion are significantly greater than those during mastication movement, but there is no significant difference in the asymmetry index of occlusal force .

Key words: the first molar, centric occlusion, mastication, occlusal force, asymmetry index of occlusal force