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BACKGROUND: The principles of minimally invasive dentistry clearly tells us the need for clinically effective measures to remineralize the early enamel caries lesions. AIMS AND OBJECTIVES: The aim of this study was to evaluate the remineralisation potential of four different remineralisation agents used quantitatively by surface microhardness and qualitatively by energy dispersive X ray analysis. MATERIALS AND METHODS: Artificial enamel lesions were created on the buccal surfaces of 60 extracted mandibular second premolar. Specimens were randomly assigned to four groups (n=15) according to the remineralisation agents used: Group 1-Nano Hydroxyapatite, Group 2-Fluoride, Group 3-CPP ACP, Group 4-Chitosan 5mg. All products were applied according to the manufacturer's instructions and specimens were stored in daily renewed artificial saliva. Surface microhardness was assessed using Rockwell hardness test and change in mineral content was evaluated using Energy Dispersive X ray analysis. STATISTICAL ANALYSIS: One way analysis of Variance test and post-hoc Tukey test were conducted for multiple group comparison. RESULTS: There was remarkable remineralisation in Hydroxyapatite treated comparatively to the other three groups. CONCLUSION: All remineralising agents showed improved surface remineralisation. However complete remineralisation did not occur within 7 days. Nanohydroxyapatite showed the highest potential for remineralisation followed by CPP-ACP, Chitosan and Fluoride.
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BACKGROUND: Endodontically treated teeth often lack sufficient support for a permanent restoration. During post space preparation, it is important not to disturb the integrity of the apical seal. AIM: This study compared the effect of immediate versus delayed post space preparation on the apical seal using four different sealers. MATERIALS AND METHODS: One hundred and thirty single rooted teeth were biomechanically prepared and obturated with single cone gutta-percha and 4 sealers: Endoflas FS, AH Plus, Gutta flow and MTA. Teeth were divided randomly into eight groups, post spaces were prepared using Gates Glidden drills immediately for group I, III, IV and VII. For groups II, IV, VI and VIII prepared after storage of the specimens in 100% humidity for one week. The samples were kept in methylene blue dye, centrifuged at 3000 rpm for 3 min sectioned and then measured under stereomicroscope for apical leakage. STATISTICAL ANALYSIS: The data was analysed using one way ANOVA and post hoc Tukey test. RESULTS: All the specimens showed dye leakage, and a statistically significant difference was seen among all the groups (P > 0.05) except Gutta flow. CONCLUSION: Less leakage is seen when post space is prepared immediately.
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AIM: This study aims to investigate the effects of finishing and polishing procedures on four novel resin composites using three-dimensional optical profilometer. MATERIALS AND METHODS: Four composites classified according to their filler size, were selected: Filtek™ Z350 XT/Nanofill (3M™ ESPE™), Esthet-X HD/Hybrid (Dentsply Caulk), Te Econom/Microfill (Ivoclar Vivadent(®)), Tetric EvoCeram(®) /Nanohybrid (Ivoclar Vivadent(®)). Composite specimens were made in Plexiglass mold and polished with Soflex (3M ESPE), Enhance + Pogo (Dentsply Caulk). Both the systems were used according to the manufacturers' instructions, and the polished surfaces were assessed with an optical profilometer. STATISTICAL ANALYSIS USED: Kruskal-Wallis test and further pairwise comparison were performed by Mann-Whitney test. RESULTS: The smoothest surfaces for all the resin composites tested were obtained from the Mylar strip; statistically significant differences were observed among them (P = 0.001). The order of composites was ranked from the lowest to highest surface roughness; Filtek Z350 XT < Te Econom < Tetric EvoCeram < Esthet XHD. Pairwise multiple comparison with Mann-Whitney test showed Filtek Z350 to have the smoothest surface and the least with Teric EvoCeram. Among the polishing systems, Soflex showed the smoothest surface and was significantly different from Pogo (P = 0.046). CONCLUSIONS: The effectiveness of the polishing systems seems to be dependent on the material used, treatment modality and also on the filler particle size.
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AIMS: To compare the fracture resistance and primary mode of failure of three different pre- fabricated posts like stainless steel, carbon fiber and ceramic posts in endodontically treated crowned permanent maxillary central incisors. MATERIALS AND METHODS: Root canal treatment was performed on all 30 maxillary central incisors. Post space was prepared and samples were divided into three groups of 10 each. The teeth were inserted with pre-fabricated stainless steel, carbon fiber and ceramic post and cemented using adhesive resins, core fabricated and crowns placed. Mode of failure was carried out by immersing the teeth in black ink for 12 h and then sectioning them mesio-distally. Fracture above the embedded resin was considered favorable and fracture below the resin level was considered unfavorable. STATISTICAL ANALYSIS: Fracture strength was measured using a universal testing machine. Data were evaluated statistically using the Kruskal Wallis test and the Mann Whitney "U"-test. Mode of failure was evaluated statistically using the chi-square test. RESULTS: There was a statistically significant difference showing that the stainless steel post had a better fracture resistance when compared with the other two posts and the carbon fiber showed a statistically more favorable fracture when compared with the other two posts. CONCLUSIONS: Within the limitations of this study, it can be concluded that the pre-fabricated stainless steel post exhibited a significantly higher fracture resistance at failure when compared with the carbon fiber post and the ceramic post. The mode of failure of the carbon fiber post was more favorable to the remaining tooth structure when compared with the pre-fabricated stainless steel post and the ceramic post.