The purpose of this study was to analyze the amount of wear with an intra-oral scahher in order to observe the wear process on implant superstructures.
This study included 30 patients who gave informed consent. Implant superstructures and antagonists on the first molar were captured with an intra-oral scanner (3M true definition scanner, 3M, St. Paul, MN, USA) when they were placed, and again 3 months later. Scanned data were imported to an image measuring program (GOM Inspect, GOM, Brunswick, Germany) and saved as STL files. Subsequently, the scanned data just after placement were compared with those after 3 months. The deviation of structural changes in functional cusps of first molars was calculated as the amount of wear. The statistical analysis was performed with the statistical analyze software (IBM SPSS, Armonk, IBM, NY, USA).
The mean amount of wear on implant superstructures was 76 ± 30 ㎛ for Zirconia(Zr) and 71 ± 27 ㎛ for Hybrid Composite Resin(HC). There were no significant differences between the two groups. The mean loss of height on the antagonist tooth was 58 ± 25 ㎛for Zr and 60 ± 20 ㎛ for HC. There were no significant differences between these groups. Moreover, there were no significant differences in wear between screw-retained superstructure and cement-retained ones. However, superstructure wear for men was significantly larger than that for women (p<0.05).
The accuracy of the intra-oral scanner was adequate for measuring the amount of wear. Thus, this measuring system could be useful for observing the morphological change of implant superstructures. There were no differences between the wear on implant superstructures made of Zr and those made. Therefore, those results indicated that Zr which was adjusted and polished properly could be applicable for implant superstructures. Moreover, there were differences between the wear of the men group and the women group, indicating that the occlusal force affected the results.
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