ABSTRACT
BACKGROUND: Recently, the caries management had shifted from extension for prevention to early detection and remineralization of remaining tooth structure using noninvasive techniques. AIM: The present trial was carried out to assess the effect of adding mono-n-Dodecyl phosphate as a surfactant to ceramic on remineralization of dentin. MATERIALS AND METHODS: The 32 teeth were divided into the following four groups randomly (n = 8 each group) - Group I: cavities not restored, Group II: Restored with ceramic, Group III: restored with ceramic and 2% mono-n-Dodecyl phosphate, and Group IV: restored with ceramic and 5% mono-n-Dodecyl phosphate. Knoop indenter microhardness tests were done at 10, 20, and 40 days. The surface was evaluated under scanning electron microscope. The collected data were subjected to statistical evaluation, and the results were formulated. RESULTS: In ceramic restored (Group II), an increase in Knoop microhardness (KHN) values was seen at 10-, 20-, and 40-day assessment with the respective values of 102.2 ± 20.3, 118.7 ± 19.4, and 127 ± 15.1. Similarly, a constant increase at different assessments was observed for Groups III and IV with 2% and 5% of mono-n-Dodecyl phosphate with ceramic with a 40-day KHN value of 128.2 ± 21.4 for Group III and 113.5 ± 17.3 for Group IV. A statistically significant difference was seen between ceramic and 5% mono-n-Dodecyl phosphate (Group IV) with hardness values of 30.31%, 29.8%, and 21.78% for Groups II, III, and IV, respectively, at 20 days. CONCLUSION: The present study concludes that ceramic restorations are effective in promoting dentin remineralization. However, the addition of only 2% mono-n-Dodecyl phosphate was beneficial, whereas 5% mono-n-Dodecyl phosphate reduced the efficacy of ceramic on dentin remineralization.
ABSTRACT
BACKGROUND: Under axial loading, there is stress concentration around the cervical areas especially in the premolars because of their location in the arch. AIM: To evaluate and compare flexural fracture resistance of mandibular premolars after instrumentation with ProTaper®Universal, ProTaper Next®, OneShape®, and WaveOne® endodontic file systems. METHODS: Seventy-five mandibular premolar teeth with single straight canals were divided into five different groups (n = 15): Group A: Control, Group B: ProTaper Universal (PTU), Group C: ProTaper Next (PTN), Group D: OneShape, Group E: WaveOne. The teeth were instrumented as per the manufacturer's instructions. After obturation and core placement, the teeth were placed in a customized jig mounted on a universal testing machine where force was applied at 45° on the buccal cusp and the force required to fracture the teeth was noted. RESULTS: Amongst all the instrumented groups, WaveOne showed the highest resistance to fracture (1065.56 ± 175.05) and the control group was 1104.13 ± 188.42. All groups showed a significant difference in the fracture load values with the control group. However, there was a statistically significant (P < 0.05) difference seen with WaveOne vs PTU and WaveOne vs OneShape. CONCLUSIONS: Root canals instrumented with reciprocating motion have better flexural fracture resistance than continuous rotary motion. Mandibular premolars when instrumented with ProTaper Universal and OneShape endodontic files showed similar fracture resistance, proving that dentin removal does not depend on the number of files used.
