Three-dimensional misfit between Ti-Base abutments and implants evaluated by replica technique

Abstract An important factor affecting the biomechanical behavior of implant-supported reconstructions is the implant-abutment misfit. Objective: This study evaluated the misfit between Ti-Base abutments and implants by means of polyvinyl siloxane replica technique using microcomputed tomography (μCT). Methodology: Volumetric and linear (central and marginal) gaps of four Ti-base abutments (n=10/group): (i) Odontofix LTDA (OD), (ii) Singular Implants (SING), (iii) EFF Dental Components (EFF), and (iv) Control Group (S.I.N implants) compatible with an implant system (Strong SW, S.I.N Implants) were measured using μCT reconstructed polyvinyl siloxane replicas. Results: The results showed significantly lower volume gap for Control S.I.N (0.67±0.29 mm3) and SING (0.69±0.28 mm3) Ti-base abutments relative to OD (1.42±0.28 mm3) and EFF groups (1.04±0.28 mm3) (p<0.033), without significant difference between them (p=0.936). While gap values were homogenous in the central region, EFF presented a significantly higher marginal gap. Accordingly, the Control S.I.N and Singular Ti-base abutments showed improved volumetric and marginal fit relative to Odontofix and EFF. Conclusion: The method of manufacturing abutments influenced the misfit at the implant-abutment interface.

Influence of the composition and shades of ceramics on light transmission and degree of conversion of dual-cured resin cements

Abstract Objective Since the transmittance of ceramics can influence the degree of conversion (DC) of resin cements, ceramics composition and shade should be considered in the selection of resin cement. This in vitro study aimed to evaluate the effect of the transmittance of different composition, opacities and shades of ceramics on the degree of conversion of two dual-cured resin cements. Methodology Sixty discs were prepared from low translucency (LT) and medium opacity (MO) lithium disilicate ceramic, and zirconia ceramic (Z). Each group was subdivided into 5 subgroups (n=4) in shades A2, A3.5, B2, C2 and D3. The transmittance measurement was performed in a spectrophotometer. The Variolink II and Rely X U200 resin cements were photoactivated by LED (1400 mW/cm2) for 40 s through the ceramic discs and without the discs (control group). The DC was measured with infrared FTIR spectroscopy, immediately after light activation. Data were analyzed with Kruskall-Wallis and one-way ANOVA, following post-hoc comparisons by Tukey test and Pearson's correlation test (P<0.05). Results LT ceramic exhibited higher transmittance values compared to MO and Z ceramics. LTA2 and LTB2 showed statistically higher transmittance values compared to MOA2, MOA3.5 and ZA3.5. For Variolink II, the ceramic interposition did not influence the DC, since there were no statistical differences between groups with ceramic interposition and the control group. For Rely X U200 cement, the interposition of some ceramics types/shades (LTA3.5, MOA2, MOA3.5 and ZA3.5) significantly decreased the DC values compared to control group. A positive correlation was found between the ceramic transmittance and DC values of both tested cements. Conclusions. The transmittance and DC values of the cements were influenced by composition and shades of the ceramics. The higher the transmittance of ceramics, the higher the DC values for both cements.

Recobrimento radicular: deslize lateral do retalho associado ao enxerto de tecido conjuntivo / Root coverage: laterally positioned flap associate with connective tissue graft

As recessões gengivais são encontradas com bastante frequência na população, gerando, em muitos casos, incômodo estético. Sensibilidade radicular também tem sido relatada, além de maior predisposição à cárie e às lesões não cariosas de abrasão e erosão na superfície radicular desnuda. A fim de alcançar um recobrimento radicular satisfatório, muitas técnicas têm sido propostas, dentre elas os enxertos gengivais livres, enxertos gengivais pediculados ou a associação de ambos. O presente artigo teve por objetivo relatar um caso clínico de recobrimento radicular através da técnica de deslize lateral do retalho associada ao enxerto de tecido conjuntivo subepitelial. O acompanhamento clínico ao longo de um ano mostrou a ocorrência de creeping attachment.

The gingival recessions are found very frequently in the population, generating in many cases, aesthetic complaint. Root sensitivity has also been reported, beyond greater predisposition to caries and non-carious lesions of abrasion and erosion on the denuded root surface. In order to achieve satisfactory root coverage, many techniques have been proposed, among them the free gingival grafts, pedicled gingival grafts or a combination of both. This article aims to report a case of root coverage using the technique of laterally positioned flap associated with the subepithelial connective tissue graft. The one-year clinical follow-up showed the occurrence of creeping attachment.