RESUMO
Aim: The study aimed to assess the remineralizing potential of four different commercially available agents using a Scanning Electron Microscope (SEM), energy dispersive X-ray (EDX) analysis, and Vickers Microhardness (VMH) Test. Materials and Methods: Forty-four specimens (n = 11 per group) were prepared from extracted teeth. A window of 6 mm × 4 mm was made on all the specimens that represented three zones, namely, sound enamel, demineralized enamel, and remineralized enamel. The zone for demineralized enamel was subjected to four different remineralizing agents; casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF), tricalcium phosphate fluoride (TCP-F), calcium sucrose phosphate (CSP), and self-assembling peptide (P11-4). Remineralization (REM) was assessed using VMH; the structural changes were assessed using SEM that was analyzed using EDX analysis. The specimens were subjected to a newer regimen of demineralization. One-way ANOVA followed by post hoc Tukey test was used with a level of significance at P ≤ 0.05. Results: There were no significant differences in VMH between the groups for sound enamel (P = 0.472) and demineralized enamel (P = 0.116). VMH was statistically significantly more for P11-4 and the least for CPP-ACPF (P = 0.011). A post hoc analysis revealed higher VMH for P11-4 compared to CPP-ACPF (P = 0.014) and TCP-F (P = 0.035). SEM showed a homogeneous layer of minerals for all groups except CPP-ACPF. TCP-F reported a higher degree of REM, followed by P11-4 as assessed using EDX analysis. Conclusion: Self-assembling peptide (P11-4) exhibited a higher degree of REM than other remineralizing agents followed by CSP.
RESUMO
Introduction: The aim of this study was to compare the shear bond strengths of zirconia to dentin using two resin-based luting cements and a resin-modified glass-ionomer cement (RMGIC). Materials and Methods: Thirty six zirconia blocks of 2 mm × 3 mm × 5 mm were milled and luted to the exposed dentin surfaces and grouped into three according to the cement used for luting: Group I - luted with Panavia F2.0, Group II - luted with RelyX U200, and Group III - luted with FujiCEM. After thermocycling, specimens were subjected to shear bond testing in an Universal Testing Machine (UTM). Data analysis using Kruskal-Wallis ANOVA and post hoc Mann-Whitney U-test with P < 0.05 was done. Results: Mean bond strengths were of the order Panavia F2.0 (5.99 MPa)>RelyX U200 (4.79MPa)>FujiCEM (1.59 MPa). Maximum failures were at the zirconia-cement interface and were adhesive in nature. Conclusions: It can be concluded with the study that there is a better bonding of zirconia to dentin with resin-based luting cements than a RMGIC. The single-step resin-luting cement RelyX U200 produced comparable bond strength to that of a multistep Panavia F2.0.
RESUMO
AIM: The purpose of this study is to evaluate and compare the incidence of dentinal defects after root canal shaping using rotary nickel-titanium (Ni-Ti) instruments (ProTaper Gold [PTG] and ProTaper Next [PTN]) and reciprocating instrument (WaveOne Gold [WOG]). MATERIALS AND METHODS: One hundred human mandibular premolars with single root and single canal with canal curvature <10° were randomly divided into five groups (n = 20 teeth per group). The root canals were instrumented using hand K-files (positive control), full sequence rotary files PTG and PTN, and reciprocating single-file system WOG. One group was left unprepared and served as negative control. Roots were sectioned horizontally at 3, 6, and 9 mm from the apex and evaluated under a stereomicroscope. RESULTS: PTG, WOG, and PTN showed dentinal defects in 40%, 53.3%and 30% of the samples, respectively. CONCLUSION: Irrespective of motion kinematics, dentinal defects are observed in all the Ni-Ti file groups. Within the limitations of the present study and the available literature, incidence of dentinal defects is less with instruments working in continuous rotation rather than instruments with reciprocating motion.