Clinical guidelines for posterior semidirect composite resin restorations: a case report with a 17-month follow-up.

Patients are always looking for conservative, esthetic, and long-lasting dental restorations, and the technique used directly influences the longevity of the treatment. The location of the restoration in the mouth and the extent of the decay influence the treatment choice. The larger the dimensions of the cavity preparation, the greater the difficulties in restoring the tooth using direct techniques. The semidirect technique, when indicated, can achieve satisfactory results. It is a relatively easy procedure, consisting of tooth preparation to receive an indirect restoration, fabrication of an alginate impression, fabrication of the composite resin restoration on a flexible cast, cementation, removal of excess cement, and occlusal adjustment. The aim of this case report is to present a viable alternative to direct and indirect restorations for posterior teeth with extensive decay. The article describes the extraoral semidirect technique for fabricating a composite resin restoration, highlighting its indications and discussing advantages and disadvantages.

A new technique for incorporation of TiO2 nanotubes on a pre-sintered Y-TZP and its effect on bond strength as compared to conventional air-borne particle abrasion and silicatization TiO2 nanotubes application on pre-sintered Y-TZP.

OBJECTIVE: This study evaluated the microshear bond strength of a resin cement to Y-TZP after different methods of TiO2 nanotubes (nTiO2) incorporation on pre-sintered Y-TZP surfaces. METHODS: nTiO2 were synthesized and incorporated on Y-TZP slices as follows (n = 15): 1) nTiO2 mixed with isopropyl alcohol/manual application (MAl); 2) nTiO2 mixed with acetone/manual application (MAc); 3) nTiO2 mixed with isopropyl alcohol/high-pressure vacuum application (HPVAl); 4) nTiO2 mixed with acetone/high-pressure vacuum application (HPVAc). As controls, surfaces were sandblasted with Al2O3 (OX) or Rocatec silicatization (ROC). All ceramics were sintered after nTiO2 incorporation. Surface treatments of OX and ROC were made after sintering. Surfaces were characterized by confocal laser microscopy, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Resin composite cylinders (1.40 mm diameter and 1 mm height) were cemented with a resin cement, stored in water at 37 °C for 24 h and thermocycled for 10 000 cycles before microshear bond strength evaluation. Data were analyzed with one-way ANOVA and Games-Howell (α = 0.05), and fracture analysis was performed using a stereomicroscope. RESULTS: EDS confirmed the presence of TiO2 on treated Y-TZP. The confocal analysis showed higher roughness for HPVAc and OX. There were significant differences between surface treatments (p < 0.001). HPVAl (22.96 ± 10.3), OX (34.16 ± 7.9) and ROC (27.71 ± 9.4) showed higher microshear bond strengths and were statistically similar (p > 0.05). MAC showed intermediary values, and HPVAc and MAl presented decreased bond strength, with a high percentage of premature debonding. CONCLUSION: High-pressure vacuum application of nTiO2 mixed with isopropyl alcohol was able to produce bond strength values compared to conventional air abrasion and Rocatec silicatization. SIGNIFICANCE: The infiltration of TiO2 nanostructures on the pre-sintered Y-TZP is an interesting approach that can improve bond strength without the need of sandblasting methods.