Introduction: The accuracy of different scanning techniques and intra-oral scan bodies (ISBs) in allocating the position of dental implants in complete overdenture digital impression has been questioned, this work compared it to conventional impression in situation where 4 parallel implants were used to simulate implant-supported overdenture situations in an in-vitro setting.
Materials and methods: A conventional and digital impressions using ISBs and 5 different scanning techniques were made of a study model having 4 parallel implants at teeth sites 36, 33, 43, and 46 which were designated as A, B, C, and D respectively. The resulting stone cast and digital impressions virtual casts were compared for linear deviations between the implant sites using a digital caliper versus computerized measurements, and for surface mismatching using a computerized superimposition process of the stone model scan and virtual models. The linear deviations measurements were statistically analyzed using the paired t test, and the horizontal deviations were statistically analyzed using the Kruskal Wallis test.
Results: Comparison of the linear measurements on the stone cast and virtual models detected significant differences in the second and third sextants of the dental arch with techniques I and IV, while superimposition horizontal deviations detected significant differences at implant positions C and D also in techniques I and IV.
Conclusions: Virtual models generated from full arch digital impressions using scan bodies and scanning techniques II, III, and V had similar accuracy to stone models developed from conventional elastomeric impressions.