Effects of Erbium Family Laser on Shear Bond Strength of Composite to Dentin After Internal Bleaching

Introduction: The aim of this study was to assess the effect of surface treatment with erbium: yttrium-aluminum-garnet (Er:YAG) and erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers on shear bond strength of composite resin to recently bleached dentin.Methods: In this study, 40 extracted human premolars were selected. The teeth were cut 4 mm apical to the cusp tip and were randomly divided into four groups (n = 10 in each group) for shear bond strength testing. For bleaching, 35% hydrogen peroxide (H2o2) gel (Opalescence Endo, Ultradent, South Jordan, UT, USA) was applied to dentin surfaces of all specimens for 10 days. Before etching and bonding, in Er,Cr:YSGG and Er:YAG laser groups, dentin surfaces were irradiated with Er,Cr:YSGG and Er:YAG lasers, respectively. In Er,Cr:YSGG group, Er:YAG group and control group, composite restoration was performed immediately after bleaching while in common procedure group, composite restoration was performed after seven days. The teeth were then subjected to shear bond strength testing machine. The data were statistically analyzed using analysis of variance (ANOVA) and Tukey test.Results: The mean and standard deviation (SD) of shear bond strength was 4.3 ± 1.4 MPa for control group, 6.7 ± 2.0 Mpa for Er,Cr:YSGG group, 14.4 ± 3.7 Mpa for Er:YAG group and 19.4 ± 2.6 Mpa for common procedure group.Conclusion: The shear strength of composite to Er:YAG laser-treated bleached dentin was significantly higher than control group while significantly lower than common procedure

Comparison of Pulpotomy with for Mocresol and MTA in Primary Molars: a Systematic Review and Meta - Analysis

Introduction: There are various studies looking at the effects of formocresol (FC) and mineral trioxide aggregate (MTA) on pulpotomy of primary molars. This is a systematic review of literature comparing the success rates of MTA and FC in pulpotomy of primary molars. Materials and Methods: The study list was obtained using PubMed, EMBASE, Scopus, Science Citation Index, Iran Medex, Google Scholar, the Cochrane Library, and also some hand searches contains through dental journals approved by the Iranian Ministry of Health. Papers which met the inclusion were accepted. The quality of studies for the meta-analysis was assessed by a series of validity criteria according to Jadad's scale. Eight qualified studies met the criteria. Terms of clinical outcomes and radiographic findings were evaluated in all studies to assess clinical success and root resorption. Fixed model was applied to aggregate the data of homogenous studies. A random effect model was carried out for measuring the effect size of heterogeneous studies. Results: The overall clinical and radiographic success rates based on the data suggested that MTA was superior to FC (P=0.004) with the Odds Ratio=3.535 and 95% confidence interval (1.494-8.369). Conclusion: Primary molars pulpotomy with MTA have better clinical and radiographic success rates than FC

Effects of Casein Phosphopeptide Amorphous Calcium Phosphate and Casein Phosphopeptide Amorphous Calcium Phosphate Fluoride on Alterations of Dental Plaque PH Following Sucrose Consumption

Background and Aim: Plaque pH drop after consumption of sugary materials may dis-solve enamel minerals. Casein phosphopeptide amorphous calcium phosphate (CPP-ACP) is a paste enriched with calcium and phosphate. The new formulation of this paste, casein phosphopeptide amorphous calcium phosphate fluoride (CPP-ACPF), contains 900 ppm fluoride. This paste can neutralize the low pH of bacterial plaque. This study compares the efficacy of CPP-ACP and CPP-ACPF for neutralizing plaque acidity at different time points. Materials and Methods: This clinical trial was conducted on 40 students. Plaque pH at the distal of first molar was measured before and 10 minutes after the consumption of 10% sucrose solution. In the next step, CPP-ACP and CPP-ACPF pastes were applied as recommended by the manufacturers to the tooth surface. Plaque pH was measured at 30 minutes, 60 minutes and 24, 48, 72 and 96 hours. Data was recorded and analyzed by repeated measures ANOVA (p<0.05). Results: Both CPP-ACP and CPP-ACPF increased plaque pH similarly in the first 48 hours. However, the pattern changed from this time point on. Conclusion: CPP-ACP and CPP-ACPF had similar efficacy for up to 48 hours, but CPP- ACPF was capable of keeping the pH high by up to 96 hours

The effect of remin pro and MI paste plus on bleached enamel surface roughness.

The growing demand for enhanced esthetic appearance has led to great developments in bleaching products. The exposure of hard tissues of the tooth to bleaching agents can affect the roughness of the enamel surface. The freshly bleached enamel surface exposed to various surface treatments such as fluoride and other remineralizing agents have been assessed in this study. The aim of this experimental study was to compare the effect of Casein Phosphopeptide-Amorphous Calcium Phosphate with Fluoride (MI Paste Plus) and Remin Pro on the enamel surface roughness after bleaching.Thirty enamel samples of sound human permanent molars were prepared for this study. After initial roughness measurement with profilometer, the samples were exposed to 37% carbamide peroxide bleaching agent 20 minutes twice, and randomly divided into three groups of ten. In group 1, a CPP-ACPF containing paste (MI Paste Plus) and in group 2, Remin Pro were applied to the teeth during a 15 day period for 5 minutes, twice a day. Samples of group 3 (control) were immersed in artificial saliva for 15 days. The roughness of all samples were measured at the beginning, after bleaching and after the study intervention and statistically analyzed.The surface roughness significantly increased in all groups following bleaching, and then it showed a decrease after application of both Remin Pro and CPP-ACPF in comparison to using bleaching agent (P0.05).There was no difference between surface roughness of MI Paste Plus and Remin Pro groups. Also the surface roughness was decreased compared to the initial enamel surface roughness

Effect of sodium bicarbonate against Candida albicans in denture stomatitis: An in vitro study

Background and Aims: The aim of this study was to investigate the effects of sodium bicarbonate against candida albicans, the main infectious factor of denture stomatitis, and to compare it with other common anti-candida medications. Materials and Methods: Three concentrations of Candida albicans (105, 106, 107 CFU/mL) were prepared. Experimental substances were 5% sodium bicarbonate, nystatin, chlorhexidine, and sterile saline (as control). Each of them was added separately to the same amounts of Candida albicans of different concentrations, and sampled at the intervals of 1, 2, 3 and 4 min. Then, the samples were cultured and incubated. The number of formed colonies was counted for each plate. The data were analyzed, using ANOVA and Tukey test. Results: Sodium bicarbonate showed a noticeable anti-candida effect on the concentrations of 105 and 106 CFU/mL, with almost similar anti-candida effect as nystatin and chlorehexidine(P=0.29, P=0.32). Nystatin was the most effective medication on the concentration of 107 CFU/mL of candida (P=0.03, P=0.01). Sodium bicarbonate and chlorhexidine were less effective in this concentration with no statistically significant difference (P=1.00). Conclusion: Sodium bicarbonate showed a significant anti-candida effect at low and medium concentrations of Candida albicans, but nystatin was more effective in the higher concentrations

Shear Bond Strength of a Resin Cement to Different Alloys Subjected to Various Surface Treatments

Objectives: Micromechanical retention of resin cements to alloys is an important factor affecting the longevity of metal base restorations. This study aimed to compare the bond strength and etching pattern of a newly introduced experimental etchant gel namely Nano Met Etch with those of conventional surface treatment techniques for nickel-chrome (Ni-Cr) and high noble alloys.  Materials and Methods: A total of 120 discs (8×10×15 mm) were cast with Ni-Cr (n=20), high noble BegoStar (n=50) and gold coin alloys (n=50). Their Surfaces were ground with abrasive papers. Ni-Cr specimens received sandblasting and etching. High noble alloy specimens (begoStar and gold coin) received sandblasting, sandblasting-alloy primer, etching, etch-alloy primer and alloy primer alone. Cylindrical specimens of Panavia were bonded to surfaces using Tygon tubes. Specimens were subjected to micro-shear bond strength testing after storing at 37°C for 24 hours. Results: In gold coin group, the highest bond strength was achieved after sandblasting (25.82±1.37MPa, P<0.001) and etching+alloy primer (26.60 ± 5.47 MPa, P<0.01). The lowest bond strength belonged to sandblasting+alloy primer (17.79±2.96MPa, P<0.01). In BegoStar group, the highest bond strength was obtained in the sandblasted group (38.40±3.29MPa, P<0.001) while the lowest bond strength was detected in the sandblast+ alloy primer group (15.38±2.92MPa, P<0.001). For the Ni-Cr alloy, bond strength in the etched group (20.79±2.01MPa) was higher than that in the sandblasted group (18.25±1.82MPa) (P<0.01). Conclusions: For the Ni-Cr alloy, etching was more efficient than sandblasting but for the high noble alloys, higher Au content increased the efficacy of etching

Effect of Root Dentin Pretreatment on Micro-Push-Out Bond Strength of Fiber Posts to Root Canal Dentin: Cold Atmospheric Argon Plasma (CAAP) and Ethylenediaminetetraacetic Acid (EDTA)

Purpose. Debonding from the root canal dentin is the most common failure mode of fiber posts. This study aimed to assess the effects of cold atmospheric argon plasma (CAAP) and ethylenediaminetetraacetic acid (EDTA) on micro-push-out bond strength of fiber posts to root canal dentin. Materials and Methods. Forty maxillary canine teeth were decoronated, underwent endodontic treatment, and were stored in an incubator for 7 days. After post space preparation, the teeth were randomly divided into four groups for different surface treatments: (I) saline, (II) 17% EDTA, (III) CAAP, and (IV) 17% EDTA + CAAP. Fiber posts (Whitepost no. 2, FGM) were cemented into the root canals using Panavia F2.0 resin cement, and 1 mm-thick sections were made at the coronal, middle, and apical thirds of the roots. The samples underwent micro-push-out bond strength test. The mode of failure was also determined under a stereomicroscope. Data were analyzed using three-way ANOVA and Tukey’s post hoc test (α = 0.05). The mode of failure data were analyzed using the chi-square test. Results. The mean micro-push-out bond strength of fiber posts was not significantly different in the four groups (P>0.05). However, the bond strength values in the coronal third were significantly higher than the corresponding values in the apical third (P=0.01). There was no significant difference in the modes of failure between the groups (P>0.05). Conclusion. Application of CAAP alone or in combination with 17% EDTA could not successfully increase the bond strength of fiber posts to root canal dentin