Influence of drilling sequence and guide-hole design on the accuracy of static computer-assisted implant surgery in extraction sockets and healed sites-An in vitro investigation.

OBJECTIVES: To evaluate the effect of drilling sequence, guide-hole design, and alveolar ridge morphology on the accuracy of implant placement via static computer-assisted implant surgery (sCAIS). MATERIALS AND METHODS: Standardized maxillary bone models including single-tooth gaps with fresh extraction sockets or healed alveolar ridge morphologies were evaluated in this study. Implants were placed using different drilling sequences (i.e., complete [CDS] or minimum [MDS]), and guide-hole designs (i.e., manufacturer's sleeve [MS] or sleeveless [SL] guide-hole designs). The time for implant placement via sCAIS procedures was also recorded. The angular, crestal, and apical three-dimensional deviations between planned and final implant positions were digitally obtained. Statistical analyses were conducted by a non-parametric three-way ANOVA (α = .05). RESULTS: Based on a sample size analysis, a total of 72 implants were included in this study. Significantly higher implant position accuracy was found at healed sites compared to extraction sockets and in SL compared to MS guide-hole design in angular, crestal, and apical 3D deviations (p ≤ .048). A tendency for higher accuracy was observed for the CDS compared to the MDS, although the effect was not statistically significant (p = .09). The MDS required significantly shorter preparation times compared with CDS (p < .0001). CONCLUSION: Implant placement via sCAIS resulted in higher accuracy in healed sites than extraction sockets, when using SL compared to MS guides, and tended to be more accurate when using CDS compared to MDS. Therefore, even though surgery time was shorter with MDS, its use should be limited to strictly selected cases.

Influence of alveolar ridge morphology and guide-hole design on the accuracy of static Computer-Assisted Implant Surgery with two implant macro-designs: An in vitro study.

OBJECTIVES: The primary aim of this in vitro study was to evaluate the influence of alveolar ridge morphologies on the accuracy of static Computer-Assisted Implant Surgery (sCAIS). The secondary aims were to evaluate the influence of guide-hole design and implant macro-design on the accuracy of the final implant position. METHODS: Eighteen standardized partially edentulous maxillary models with two different types of alveolar ridge morphologies were used. Each model was scanned via cone beam computer tomography prior to implant placement and scanned with a laboratory scanner prior to and following implant placement using sCAIS. The postsurgical scans were superimposed on the initial treatment planning position to measure the deviations between planned and postsurgical implant positions. RESULTS: Seventy-two implants were equally distributed to the study groups. Implants placed in healed alveolar ridges showed significantly lower mean deviations at the crest (0.36 ± 0.17 mm), apex (0.69 ± 0.36 mm), and angular deviation (1.86 ± 0.99°), compared to implants placed in fresh extraction sites (0.80 ± 0.29 mm, 1.61 ± 0.59 mm, and 4.33 ± 1.87°; all p<0.0001). Implants placed with a sleeveless guide-hole design demonstrated significantly lower apical (1.02 ± 0.66 mm) and angular (2.72 ± 1.93°) deviations compared to those placed with manufacturer's sleeves (1.27 ± 0.67 mm; p = 0.01, and 3.46 ± 1.9°; p = 0.02). Deep-threaded tapered bone level implants exhibited significantly lower deviations at the crest (0.49 ± 0.28 mm), apex (0.97 ± 0.63 mm), and angular deviations (2.63 ± 1.85°) compared to shallow-threaded parallel-walled bone level implants (0.67 ± 0.34 mm; p = 0.0005, 1.32 ± 0.67 mm; p = 0.003, and 3.56 ± 1.93°; p = 0.01). CONCLUSIONS: The accuracy of the final implant position with sCAIS is determined by the morphology of the alveolar ridge, the design of the guide holes, and the macrodesign of the implant. CLINICAL SIGNIFICANCE: Higher accuracy in the final implant position was observed with implants placed in healed alveolar ridge morphologies, in implants with deep-threaded tapered macro-design, and when sleeveless surgical guide holes were used.