Effect of additive manufacturing technology and print orientation on the accuracy of static guided implant surgery: An in vitro study

PURPOSE: The aim of this in vitro study was to investigate the effect of print orientation and printing technology on the accuracy of static computer-aided implant surgery (s-CAIS). MATERIALS AND METHODS: A cone beam computed tomography (CBCT) scan and a partially edentulous mandibular intraoral scan (IOS) of an unidentified patient missing the mandibular right first molar were used for this study. Fifty-two resin models were printed from the obtained IOS. Digital implant planning software CoDiagnostiX was used to virtually plan the implant based on a prosthetically driven approach. A tooth-supported surgical guide was designed, and the resultant STL files were then used to manufacture 52 different guides. Two different printing technologies were employed: stereolithography (SLA) and digital light processing (DLP). The groups were further subdivided according to print orientation into 0° and 45° orientations, with 13 guides per group (n = 13). Fifty-two fully guided implants were placed in their respective models. Scan bodies were placed on each implant, and an intraoral implant scan was obtained. Post-placement STL files were then imported into the CoDiagnostiX treatment evaluation tool to assess the accuracy of the placed implants compared to the planned ones. Three different parameters were assessed: implant angular deviation, deviation at the entry point, and deviation at the apex. Two-way analysis of variance (ANOVA) and post hoc Tukey pairwise comparison tests were used to compare the means, with a significance level set at p < 0.05 (α = 0.05) using the R programming language. RESULTS: No statistically significant difference was observed in mean angular deviation among the groups (p > 0.05). At the entry point, the 45° SLA group demonstrated the lowest mean deviation (0.86 ± 0.13 mm), which was significantly lower than 0° SLA (1.35 ± 0.22 mm), 0° DLP (1.23 ± 0.20 mm), and 45° DLP (1.11 ± 0.29 mm) (p < 0.05). No significant differences were observed between 0° DLP and 0° SLA or between 0° DLP and 45° DLP. At the apical level, the 45° SLA group exhibited the lowest mean deviation (1.16 ± 0.23 mm) and differed significantly from both 0° SLA (1.45 ± 0.25 mm) and 0° DLP (1.49 ± 0.32 mm) (p < 0.05), whereas no significant differences were found between 45° SLA and 45° DLP. CONCLUSION: Overall, print orientation (0° vs. 45°) and printing technology (SLA vs. DLP) did not significantly affect angular deviation. For the SLA group, printing at a 45° orientation significantly reduced the offset at both the entry point and the apex compared to the 0° orientation, with results favoring the 45° orientation. In contrast, print orientation did not significantly influence accuracy in the DLP group.