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Aim and Objective: This study was intended to compare and determine the potency of strontium-doped nano-hydroxyapatite paste against a topical cream containing casein phosphopeptide-amorphous calcium phosphate and a regular dentifrice for remineralization of white spot lesions of enamel following orthodontic debonding. Methods: Ninety individuals with white spot lesions on their enamel who visited the orthodontic department for de-bonding were selected for the research. Patients were randomly assigned to three distinct groups with each group consisting of 30 patients. Group 1 served as the control and received regular dentifrice, Group 2 received strontium-doped nano-hydroxyapatite paste, and Group 3 received casein phosphopeptide-amorphous calcium phosphate topical cream. Patients were instructed to locally apply a specified amount of the prescribed preparation twice daily for six weeks. The data were analysed using the statistical programme SPSS 22.0 (SPSS Inc., Chicago, IL, USA), and the level of significance had been set at p < 0.05. Results: Group 1 did not show any change in the enamel following the application of toothpaste. Both Group 2 and 3 demonstrated higher post-treatment scores, indicating effective remineralization potential (p < 0.001). However, Group 2 (strontium-doped nano-hydroxyapatite paste) displayed significantly greater remineralization capacity when compared to group 3 (casein phosphopeptide-amorphous calcium phosphate topical cream). Conclusion: Compared to conventional dentifrice and casein phosphopeptide-amorphous calcium phosphate paste, strontium-doped nano-hydroxyapatite preparation demonstrated greater enamel remineralization of the white spot lesions and favourable surface alterations in the enamel surface. strontium-doped nano-hydroxyapatite can be utilised safely and efficiently to treat early caries and remineralise white spot lesions on the enamel.
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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.
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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.