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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

PurposeTo investigate the repair bond strength (RBS) of a resin composite to six restorative materials either mediated by application of a silane and a bonding agent or by application of a universal adhesive. Methods and MaterialsThirty specimens were produced from each restorative material: an amalgam alloy (ORALLOY MAGI-CAP S), a direct resin composite (Filtek Z250), two indirect resin composites (Paradigm MZ100 and Lava Ultimate), a hybrid ceramic (VITA ENAMIC), and a feldspar ceramic (VITABLOCS Mark II). The specimens were stored for 3 months in tap water (37°C) for artificial ageing. After storage, the surfaces of all specimens were sandblasted (aluminum oxide, grain size: 25 μm), water-sprayed, and air-dried.Subsequently, the surfaces of half of the specimens (n=15/restorative material) were treated with a silane (Monobond Plus) followed by application of a bonding agent (OptiBond FL Adhesive) whereas the other half was treated with a universal adhesive only (Scotchbond Universal). A resin composite (Filtek Z250) was applied as repair material on the treated surfaces and the specimens were stored for 24 hours (37°C, 100% humidity).Then, RBS was measured by means of a shear bond strength test. Due to normally distributed data (Shapiro Wilk's test: p=0.216), RBS-values were analyzed with a parametric ANOVA and twosample t-tests. The p-values were corrected with Bonferroni-Holm adjustment for multiple testing (significance level: =0.05). ResultsThe RBS-values are shown in Figure 1. Mean values (standard deviations) (MPa; Monobond Plus and OptiBond FL Adhesive / Scotchbond Universal) were: 18.6 (3.2) / 17.2 (3.1) for ORALLOY MAGICAP S, 19.8 (3.9) / 17.0 (3.5) for Filtek Z250, 19.9 (3.2) / 17.6 (3.7) for Paradigm MZ100, 20.5 (4.2) / 18.1 (4.6) for Lava Ultimate, 23.9 (5.0) / 17.1 (3.2) for VITA ENAMIC, and 22.3 (4.3) / 12.5 (4.9) for VITABLOCS Mark II.For VITA ENAMIC and VITABLOCS Mark II, treatment with Monobond Plus and OptiBond FL Adhesive showed a significantly higher RBS than did treatment with Scotchbond Universal (p≤0.0009). For the other four restorative materials, RBS did not significantly differ between the two treatments (p≥0.207). Conclusion Clinically (with the exception of amalgam alloy), the material of a restoration to be repaired may be unknown.Consequently, when repairing restorations with resin composite it seems advisable to use a silane followed by a bonding agent since for two out of the six restorative materials investigated, the use of a universal adhesive showed lower repair bond strength.