Effect of metal sleeve integration on implant placement accuracy using additively manufactured tooth-supported surgical guides: an in vitro study

Abstract Background This in vitro study evaluated whether the incorporation of metal sleeves influences implant placement accuracy when using additively manufactured tooth-supported surgical guides. Methods Thirty-two partially edentulous maxillary resin models were allocated to two groups: tooth-supported surgical guides with metal sleeves and sleeveless guides (n = 16 per group). Both guide designs were generated from the same virtual implant plan and manufactured using LCD-based vat photopolymerization. A VEGA implant measuring 4.0 × 10 mm was placed at the maxillary right second premolar site (FDI 15) in each model under standardized laboratory conditions. After implant placement, scan abutments were connected and the models were digitized using a laboratory scanner. The postoperative STL files were aligned with a master reference STL obtained from a physical reference model reproducing the planned implant position. Crestal horizontal, crestal vertical, and angular deviations were measured. Between-group differences were assessed using the Mann–Whitney U test, with the significance level set at α = 0.05. Results No statistically significant differences were identified between the sleeveless and metal-sleeved groups for crestal horizontal deviation (median: 0.36 vs. 0.28 mm; p = 0.287), crestal vertical deviation (median: 0.53 vs. 0.63 mm; p = 0.402), or angular deviation (median: 8.00° vs. 10.00°; p = 0.171). Conclusions Under the conditions of this in vitro study, the incorporation of metal sleeves did not significantly influence the accuracy of implant placement using additively manufactured tooth-supported surgical guides. Sleeveless guides achieved accuracy comparable to that of metal-sleeved guides and may represent a viable alternative when appropriate digital planning, manufacturing, and guided surgical protocols are followed. Further clinical studies are required to confirm these findings.