Effect of reusing impression posts and scan bodies on recording accuracy

Abstract

Statement of problem

The frequent reuse and sterilization of dental implant transfer components (ITCs) may cause deformation. Whether the reuse will compromise the accuracy of implant-supported restorations is unclear.

Purpose

The purpose of this in vitro study was to evaluate the effects of repeated use and sterilization on the accuracy of ITCs and to determine the acceptable number of reuses before significant deformation occurs.

Material and methods

Both conventional impression making and digital scanning were evaluated. The conventional groups were Group CS (Conventional Straumann), Group CD (Conventional Dio), and Group CM (Conventional Mode). For each group, 5 indirect impression copings were used on 3 different dental implants placed in casts. Impressions were repeated 10 times per coping, with sterilization at 134 °C for 10 minutes between each impression. The digital groups were analyzed by scanning casts with an intraoral scanner and scan bodies. The digital groups included Group DS (Digital Straumann), Group DD (Digital Dio), and Group DM (Digital Mode). Scans were repeated 10 times per scan body on a reference cast, with sterilization at 134 °C for 5 minutes between scans. Deviations between the casts were analyzed with a 3-dimensional software program. The root mean square (RMS) and deviation values according to implant brand, group, and impression or scanning order were compared with 3-way mixed ANOVA with repeated measures. A simple effect analysis with Bonferroni adjustment was performed for multiple comparisons (α=.05).

Results

Repeated use and sterilization led to significant increases in deviations across all groups. In the conventional groups, RMS deviation for Group CS increased from 0.0304 to 0.0702 mm, for Group CD from 0.0522 to 0.1145 mm, and for Group CM from 0.0609 to 0.1047 mm over 10 impressions. For the digital groups, the RMS deviation for Group DS increased from 0.0149 to 0.0652 mm, for Group DD from 0.0134 to 0.0554, and for Group DM from 0.0203 to 0.0810 mm. All increases were statistically significant (P<.05).

Conclusions

The repeated use and sterilization of ITCs led to significant deformation, reducing accuracy in both conventional impressions and digital scans. To maintain high accuracy, the reuse of ITCs should be limited based on the observed increase in deviations.