Accuracy Evaluation of Definitive Casts Obtained from Conventional and Digital Impression Methods for Kennedy Class IV Partially Edentulous Maxillary Arches: an in Vitro Study.
Abstract: Purpose: This study compared the accuracy of definitive casts obtained by conventional impressions with those obtained from two different intra-oral scanners (Dental Wings and True Definition). Material and Methods: Two maxillary partially edentulous clear acrylic casts with teeth # 7, 8, 9, and 10 missing were fabricated to simulate a Kennedy class IV clinical condition. Both casts were... read moreoutfitted with two internal connection implant analogs in sites # 7 and 10, Bone Level RC implant analogs (Straumann USA, Andover, MA) in one cast, and Nobel Conical Connection RP implant analogs (Nobel Biocare, Yorba Linda, CA) in the other. The study had 6 groups. Groups I and II included casts produced from conventional impressions, which were then digitized (n=10 each). Groups III and IV consisted of digital impressions obtained with a 3Shape True Definition intra-oral scanner (n=10 each). For groups V and VI a Dental Wings intra-oral scanner was used to produce the digital impressions (n=10 each). Results: For the Straumann implant system, the True Definition intra-oral scanner was the most accurate with a median ± IQR 3-D deviation of 18.1 ± 4.7μm. No statistically significant differences between the three groups (p = 0.400) were noted. For the Nobel Biocare system, the Dental Wings intra-oral scanner was the most accurate with a median ± IQR 3-D deviation of 15.9 ± 3.2μm. A statistically significant difference between the Dental Wings digital impression and the conventional impression group, which had a median ± IQR of 25.3 ± 2.9 μm) was found. The difference between Straumann and Nobel Biocare casts was significant for Dental Wings digital impressions (p=0.023), but not for the other two impression techniques (p=0.579 for conventional, p=0.853 for True Definition). Conclusions: Within the limitations of the current study, the Dental Wings intra-oral scanner showed the least 3-D deviation for the Nobel Biocare implant system with a statistically significant difference when compared to the conventional impression method. The True Definition scans showed the least 3-D deviations for the Straumann Bone Level RC system, but no statistically significant differences between the three groups were observed. Dental Wings digital impressions showed less 3-D deviation values for the Nobel Biocare system than the Straumann system with a statistically significant difference.
Thesis (M.S.)--Tufts University, 2016.
Submitted to the Dept. of Posthodontics.
Advisor: Hans Weber.
Committee: Mathew Finkelman, Yukio Kudara, Khaled Elrafie, and Pano Papaspyridakos.
Keyword: Dentistry.read less