A comparative study of the accuracy between conventional and digital impressions in different implant angulations and depths

To compare the accuracy of implant impression technique between conventional and digital impressions (digital scans) in different implant angulations and depths (gingival heights). Seven master models with polyester resin and condensation-cured silicone, featuring three dental implants at 0°, 15°, and 30° buccal angulations and varying gingival heights (GH2-8), were used. Seventy STL files were generated using conventional impressions and digital scans. Accuracy of the impressions were evaluated by comparing STL files to the reference models, measuring linear and angular deviations. Trueness was determined by average deviation, while precision was assessed by intra-group variation. Statistical significance was set at p ​< ​0.05. This study revealed that, in the 0-degree group, no significant differences were found between the two impression methods at different heights. The 15-degree buccally angulated implant showed significant differences between GH4 and GH8 (p ​= ​0.009), while a 30-degree buccally angulated implant showed significant differences between GH 4 and GH 6, 7, 8 (p ​= ​0.013, 0.005, 0.003 respectively). Digital scans consistently exhibited significantly lower angular deviation of precision compared to conventional impressions, except for GH2 (p ​< ​0.001). There were no statistically significant differences in the precision of linear deviation. Within the limitations of this in vitro study, no significant differences in accuracy were observed between the two impression methods at different heights in the parallel groups, but significant differences found when implant depths in angulated implants were increased.