The practice of restorative dentistry has changed dramatically with the introduction of innovative technique and materials. Adhesive RESIN systems are examples of these materials that have led to the popularity of bonded ceramics and RESIN-retained fixed partial dentures. Many researches have been performed to increase bond strength of adhesive material to dental structures and metal surfaces. The main goals in bonding systems are: retention, elimination or reduction of microleakage and reinforCEMENT of the remaining tooth structures. The present article is a systematic review of researches on adhesive RESIN systems, from 1980-2002, which have been founded in Medline.      

Introduction: Various surface treatments have been used to improve the adhesion of RESIN CEMENT to zirconia restorations. The present study aimed to investigate the effects of different surface treatments on the bond strength of RESIN CEMENT to zirconia (Y-TZP) in clinical practice. Methods: thirty square Y-TZP samples were classified into three groups of 10, including group SB (50 μ m sandblasted Al2O3 particles), group B (diamond burs), and group C (control). One sample from each group was subjected to X-ray powder diffraction, scanning electron microscopy (SEM), and profilometer analysis. The shear bond strength (SBS) of zirconia-RESIN CEMENT was measured using a universal testing machine at the crosshead speed of 1 mm/min until bonding failure. SBS values were analyzed using analysis of variance (ANOVA) and Tukey’ s HSD test (α =0. 05). Results: According to the results of ANOVA, SBS was significantly affected by the treatment method. Tukey’ s HSD test showed significant differences between the groups (P<0. 05). Groups SB (9. 99± 0. 78 MPa) and B (9. 30± 0. 67 MPa) had significantly higher SBS values compared to group C (6. 47± 1. 33 MPa) (P<0. 05), while they had no significant differences with each other in this regard (P>0. 05). In addition, SEM evaluations indicated morphological differences between the Y-TZP samples. According to the results of X-ray diffractometer, monoclinic phase transformation was observed in group SB only (28%). Conclusion: According to the results, grinding and sandblasting were both effective in chairside surface treatments for improving the bond strength of the RESIN CEMENT to Y-TZP. However, it should be considered that sandblasting may cause phase transformation.

Background. New surface treatments have been proposed to expand the clinical indications of zirconia prostheses. This study aimed to evaluate the effect of silica and fluorine nanofilms on zirconia ceramic on the RESIN CEMENT bond strength. Methods. Zirconia blocks and discs underwent different surface treatments: untreated zirconia (CON), sandblasted, silica-coated alumina particles (30 μ, m) (SC), silica nanofilm (SN), and fluorine nanofilm (FN). Nanofilm deposition was performed through plasma enhanced chemical vapor deposition (PECVD). Zirconia surfaces were characterized on disks by morphology (atomic force microscopy, AFM), chemical analysis (x-ray photoelectron spectroscopy, XPS), and contact angle analysis. A silane coupling agent was applied on each treated surface, and a cylinder of RESIN CEMENT was built up. Half of the specimens in each group were submitted to 6000 thermal cycles (TC). Bond strength was analyzed using the shear test, and the fractographic analysis was performed with stereomicroscopy and SEM/EDS. Statistical analysis was performed through one-way ANOVA and Tukey test in the non-aged and aged specimens. Results. Nanofilms modified the zirconia surface, which became more hydrophilic and chemically reactive. Chemical bonding between Si-O was found in SN, and FN promoted a fluorination process on the ceramic surface, converting zirconia into zirconium oxyfluoride. Specimens of the SN (TC) group failed on pre-testing. FN (TC) bond strength (3. 8 MPa) was lower than SC (TC) and CON (TC) after shearing. Adhesive failure predominated in the experimental groups. Silica nanofilm failure occurred after aging. Conclusion. Silica and fluorine nanofilms deposited by PECVD did not promote effective bonding between zirconia and RESIN CEMENT.

Objectives: Hydroxyapatite (HA) nanoparticles are used to improve the physical and mechanical properties of glass ionomers (GIs). This study aimed to assess the effect of addition of different weight percentages of nano-HA on degree of conversion (DC) of Fuji II LC GI CEMENT using a spectrometer. Materials and Methods: In this in vitro experimental study, 30 samples were fabricated of Fuji II LC (improved) GI CEMENT in six groups (n=5) containing 0%, 1%, 2%, 5%, 7% and 10wt% nano-HA. The obtained paste in each group was subjected to Fourier-transform infrared spectroscopy (FTIR) before curing to assess the monomer to polymer DC percentage. The paste was then light-cured and underwent FTIR again. One-way ANOVA was applied to compare the DC percentage of different groups. Pairwise comparisons were performed using the Tukey’ s test. Results: The DC was 57. 88± 0. 57% in 0%, 60. 04± 0. 63% in 1%, 66. 92± 0. 54% in 2%, 65. 5± 0. 71% in 5%, 51. 49± 0. 24% in 7% and 50. 09± 0. 32% in 10% nano-HA group. The difference in DC among the groups was statistically significant (P<0. 0001). The highest DC was noted in 2% nano-HA and the lowest DC was found in 10% nano-HA group. Pairwise comparisons revealed significant differences between the groups in DC (P<0. 0001). Conclusion: Increasing the weight percentage of nano-HA to 2% increased the DC but increasing the nano-HA weight percentage over 5% decreased the DC of RESINmodified glass ionomer CEMENT (RMGIC). The highest DC was noted in 5w% and 2w% nano-HA groups. Thus, 5w% and 2w% nano-HA can be used to improve the DC of RMGIC.