Influence of 3D Printing, Implant Macro-Design and Alveolar Ridge Morphology on Accuracy and Primary Stability in Static Computer-Assisted Implant Surgery: An In Vitro Study.

OBJECTIVES

To assess the positional accuracy of static computer-assisted implant surgery (sCAIS) using guides printed by digital light processing (DLP) or material extrusion (ME), and to compare insertion torque (IT) and implant stability quotient (ISQ) of two tissue-level implants (Straumann TLC, TLX) in healed premolar ridges versus molar extraction sites in vitro.

METHODS

Eighty implants were placed in standardized resin bone models using DLP- or ME-printed guides. Angular, crestal, and apical deviations were determined by superimposing preoperative and postoperative scans; IT and ISQ were recorded. Statistical analysis was performed with three-way ANOVA, aligned rank transform ANOVA and ordinal logistic regression.

RESULTS

Healed premolar ridges showed smaller angular (2.35 ± 1.36° vs. 3.33 ± 1.62°), crestal (0.50 ± 0.20 vs. 0.75 ± 0.36 mm), and apical deviations (0.86 ± 0.41 vs. 1.33 ± 0.63 mm) than molar extraction sites (p<0.01). Printing technology did not affect accuracy, but ME guides showed lower IT. TLC deviated more than TLX but reached higher ISQ (81.58 ± 6.03 vs. 77.18 ± 5.18; p<0.01) and IT.

CONCLUSIONS

In vitro, DLP and ME guides showed no significant difference in positional accuracy. TLC achieved higher IT and ISQ but greater deviation than TLX. Deviations were smaller at healed premolar ridges than at molar extraction sites.

CLINICAL SIGNIFICANCE: ME-printed guides showed accuracy comparable to DLP-printed guides in vitro, however clinical equivalence requires in vivo confirmation. Larger deviations should be anticipated at molar extraction sites, with adequate safety margins. Implant macro-design affected accuracy and primary stability in opposite directions.