This study evaluates the effect of phosphoric acid etching of enamel margins on the microleakage of a simplified all-in-one and a self-etching adhesive system in comparison to a conventional total-etch system. SUMMARYSixty buccal Class V cavities with beveled enamel margins were made at the cemento-enamel junction of extracted human premolars and randomly divided into five groups of 12 specimens. Clearfil SE bond was applied to Group 1; Group 2 had 35% phosphoric acid etching of the enamel margins plus Clearfil SE Bond; Group 3 was administered iBond; Group 4 had 35% phosphoric acid etching of the enamel margins plus iBond and Scotchbond Multi-Purpose was used on Group 5. All the groups were restored with a resin composite. After 24 hours of storage in 100% humidity, the samples were thermocycled, immersed in a dye solution and sectioned buccolingually and microleakage of the enamel margins was evaluated on a scale of 0 to 2. Differences among Groups 3 and 4 and Groups 3 and 5 were significant (p<0.05); however, no statistically significant differences were found between the other groups (p>0.05). The current study shows that simplified all-in-one adhesive systems need

In this laboratory study shear bond strengths of three filled and one unfilled adhesive systems to enamel and dentine were compared. Forty-eight extracted intact noncarious human mandibular molars were randomly assigned to two groups of 24 one for bonding to enamel and the other for bonding to dentine. Buccal and lingual surfaces of each tooth were randomly assigned for application of each one of filled (Prime & Bond NT (PBNT), Optibond Solo Plus (OBSP), and Clearfil SE Bond (CSEB)) and unfilled (Single Bond (SB)) adhesive systems (n = 12). A universal resin composite was placed into the translucent plastic cylinders (3 mm in diameter and 2 mm in length) and seated against the enamel and dentine surfaces and polymerized for 40 seconds. Shear bond strength was determined using a universal testing machine, and the results were statistically analyzed using two-way ANOVA, one-way ANOVA, t-test, and Tukey HSD post hoc test with a 5% level of significance.There were no statistically significant differences in bond strength between the adhesive systems in enamel, but CSEB and SB exhibited significantly higher and lower bond strength to dentine, respectively, than the other tested adhesive systems while there were no statistically significant differences between PBNT and OBSP.

Objective:There is no definitive study comparing stress distribution around two versus three implants in implant-retained overdentures with different cantilever length. The purpose of this finite element study was to evaluate stress pattern around the implants of the 2 or 3 implant- supported mandibular overdenture with different cantilevered length.Materials and Methods:The models used in this study were 2 and 3 implant-supported overdenture with bar and clip attachment system on an edentulous mandibular arch. Each model was modified according to cantilever length (0 mm, 7 mm, and 13 mm); thus, 6 models were obtained. The vertical load of 15 and 30 pounds were applied unilaterally to the first molar and 15 pounds to the first premolar, and the stress in bone was analyzed.Results:With increasing cantilever length, no similar stress pattern changes were observed in different areas, but in most instances, an increase in cantilever length did not increase the stress around the implant adjacent to cantilever.Conclusions:Within the limitations of this study, it can be concluded that increasing of cantilever length in mandibular overdentures retained by 2–3 implants did not cause distinct increasing in stress, especially around the implant adjacent to cantilever, it may be helpful to use cantilever in cases of mandibular overdenture supported by splinted implants with insufficient retention and stability. Based on the findings of this study, optimal cantilever length in mandibular overdenture cannot be determined.

Amelogenesis imperfecta (AI) has been defined as a group of hereditary enamel defects. It can be characterized by enamel hypoplasia, hypomaturation, or hypocalcification of the teeth. AI may be associated with some other dental and skeletal developmental defects. Restoration for patients with this condition should be oriented toward the functional and esthetic rehabilitation. This clinical report describes the oral rehabilitation of a young patient diagnosed with the hypoplastic type of AI in posterior teeth and hypomatured type of AI in anterior teeth.

Background:Chip-off fracture of veneering porcelain has been described as the most frequent reason for the failure of zirconia-based fixed partial dentures. The purpose of this study was to evaluate the shear bond strength (SBS) of two commercial zirconia core ceramics to their corresponding veneering ceramics.Materials and Methods:Zirconia disks with 7-mm diameter and 3-mm height were prepared (Cercon and Biodenta systems) and veneered with recommended layering ceramics (Cercon ceram and 2 in 1 ceramic, respectively) (n = 10). The disks were polished with diamond paste and airborne-particle abraded before layering. The specimens were mounted in a T-shaped metal holder using autopolymerized acrylic resin and stored in 37°C distilled water for one week, after which they were subjected to thermal cycling. SBS of zirconia core to veneering ceramic was measured using a universal testing machine and failure modes were determined microscopically. Data were analyzed using t test (α < 0.05).Results:Mean (±SD) SBS values were 27.19(±3.43) and 28.22(±4.08) MPa for Cercon and Biodenta systems, respectively, with no significant difference. Biodenta system showed more adhesive failure compared to more combined (adhesive and cohesive) failures in Cercon system.Conclusion:Within the limitations of this study it can be concluded that SBS of Biodenta and Cercon specimens were nearly the same, but the fracture mode of these two systems were different. Since Biodenta fracture pattern was predominantly adhesive, it seems that maybe Biodenta porcelain was stronger than Cercon porcelain where as its adhesive bond was weaker.