Accuracy of Scanned Stock Abutments Using Different Intraoral Scanners: An In Vitro Study.

PURPOSE: To determine the accuracy of a digital manufacturing method for dental implant restorations on stock abutments using intraoral scanners and prefabricated stock-abutment libraries. MATERIALS AND METHODS: Two dental implants with internal hexagonal connections were placed in the mandibular second premolar and second molar areas of a partially edentulous dentoform model; stock abutments with a diameter of 5 mm, abutment height of 5.5 mm, and gingival cuff height of 2 mm were connected. The study model was scanned 10 times using a reference tabletop scanner and 5 types of intraoral scanners (IOSs). The data collected by 5 types of IOSs were divided into 3 groups, based on the type and matching of stock abutment library data: no library, optical library, and contact library groups. A total of 160 data files were analyzed, including reference data. The resulting data were used to evaluate trueness and precision. RESULTS: Trueness and precision values in the group in which library data of the stock abutment were not used were 42.0 to 76.3 µm and 30.5 to 99.7 µm; corresponding values when the library data using an optical scanner were matched were 51.2 to 73.4 µm and 26.3 to 62.8 µm, and those when contact scanner library data were used were 30.1 to 62.4 µm and 15.5 to 55.9 µm. Thus, the accuracy of the contact library group was significantly higher than the accuracies of the no library (p < 0.001) and optical library groups (p < 0.001). CONCLUSION: The application of prefabricated library data of stock abutments using a contact scanner improved the accuracy of scan data. Scan accuracy of the stock abutments differed significantly based on the type of scanner.

Effects of hydrophilicity and fluoride surface modifications to titanium dental implants on early osseointegration: an in vivo study.

PURPOSE: The purpose of this study was to investigate in vivo histomorphometric differences in initial bone response to modified sand-blasted, large-grit, acid-etched (modSLA), and fluoride-modified (F-mod) implant surfaces in rabbit tibia models. MATERIALS AND METHODS: Field emission scanning electron microscopy (FE-SEM), confocal laser scanning microscopy (CLSM), and x-ray photoelectron spectroscopy (XPS) were used to determine surface characteristics. Each of 3 live New Zealand white rabbits received an F-mod implant in one tibia and a modSLA implant in the other. After 1 week, the rabbits were killed, and the undecalcified histologic slides were prepared. Bone-to-implant contact (BIC) ratio and bone area (BA) were calculated in a defined area under a light microscope. RESULTS: FE-SEM, CLSM, and XPS showed that the modSLA surface was significantly rougher than the F-mod, and that the F-mod surface had a very small amount of fluoride. However, despite these surface variances, histomorphometric analyses revealed no significant differences in either BIC or BA. CONCLUSIONS: Our results suggest that the in vivo effects of increased hydrophilicity, when added to a titanium dental implant surface, on early bone response may be similar to the effects of surface fluoride treatment.