Relationship between the Depth of Penetration and Fracture Resistance of Various Sealers: A Comparative Study.

AIM: The aim of this in vitro study was to estimate the penetration depth and fracture resistance of three different sealers and to verify the relationship between the penetration depth and fracture resistance. MATERIALS AND METHODS: Sixty single-rooted teeth were selected and root canal preparation was done. After the instrumentation, the teeth were divided into three groups of 20 each. The groups were then obturated with gutta-percha (GP)-AH Plus sealer, Resilon-Real Seal, and propoint-bioceramic sealers, respectively. Ten teeth from each group were sectioned at three different regions (i.e., coronal, middle, and apical thirds of the root canal) and were viewed under a confocal microscope to determine the penetration depth of the sealer. The remaining samples were subjected to fracture resistance under a universal testing machine and the statistical analysis was done by using one-way ANOVA and post hoc Bonferroni tests. RESULTS: Propoint-bioceramic group showed the highest fracture resistance values followed by GP-AH Plus sealer and Resilon-Real seal groups with no significant difference noticed between them. Depth of penetration was greater for GP-AH Plus sealer, propoint-bioceramic, with no significant difference followed by the Resilon-Real seal group. CONCLUSION: The newer obturating material propoint-bioceramic group showed a greater fracture resistance. No correlation could be established between the depth of sealer penetration and fracture resistance. CLINICAL SIGNIFICANCE: Fracture resistance of tooth obturated with propoint-bioceramic sealer combination is significantly greater than GP-AH Plus and Resilon-Real seal combination, thereby showing propoint-bioceramic as a promising obturating material.

Incremental techniques in direct composite restoration.

Polymerization shrinkage is one of the dental clinician's main entanglements when placing resin-based composite restorations. None of the method can assure a perfectly sealed restoration for adhesive restorative materials; clinicians must abode problems of polymerization shrinkage and its possible ill effects. The objective of this article is to review different incremental techniques that can ruin the polymerization shrinkage stress of direct composite restoration.

Effect of Peracetic Acid as A Final Rinse on Push Out Bond Strength of Root Canal Sealers to Root Dentin.

BACKGROUND: Smear layer which was formed during the instrumentation of root canals hinders the penetration of root canal sealers to root dentin and affect the bond strength of root canal sealers to root dentin. Final irrigant such as demineralizing agents are used to remove the inorganic portion of the smear layer. In the present study, peracetic acid used as a final rinse, to effect the bond strength of root canal sealers to root dentin. AIM: The purpose of the present study was to evaluate the efficacy of peracetic acid as a final irrigant on bond strength of root canal sealers to root dentin. MATERIALS AND METHODS: Sixty six freshly extracted human single rooted mandibular premolars were used for this study. After decoronation the samples were instrumented with Protaper upto F3 and irrigated with 5.25% NaOcl. The teeth were then divided into three groups based on final irrigant used: Group-1(control group) Canals were irrigated with distilled water. Group-2: Canals were irrigated with peracetic acid. Group-3: Canals were irrigated with smear clear. Each group was further divided into three subgroups (n=30) based on the sealer used to obturate the canals. Subgroup-1: kerr, Subgroup-2: Apexit plus, Subgroup-3: AH PLUS. Each sealer was mixed and coated to master cone and placed in the canal. The bonding between sealer and dentin surface was evaluated using push out bond strength by universal testing machine. The mean bond strength values of each group were statistically evaluated using Two-way ANOVA followed by Tukey post-hoc test. RESULTS: Significant difference was found among the bond strength of the sealers. But, there is no statistically significant difference between the groups irrigated with peracetic acid and smear clear compared to control group. AH Plus showed highest bond strength irrespective of the final irrigant used. CONCLUSION: Peracetic acid when employed as final irrigant improved the bond strength of root canal sealers compared to control group but not statistically significant than smear clear.

A Review on Perforation Repair Materials.

Perforation is an artificial communication between the root canal system and supporting tissues of the teeth. Root perforation complicates the treatment and deprives the prognosis if not properly managed. A wide variety of materials to seal the perforations have been suggested in literature. There are many comparative studies showing the efficacy of one material over the other. Literature shows many reviews on diagnosis, treatment plan and factors affecting prognosis of perforation repair; but none of these articles elaborated upon various materials available to seal the perforation. The present article aims at describing all the materials used for perforation repair from the past till date; it also offers a literature review of all the articles published over last four decades referred to the treatment of perforation with various root repair materials.

Comparative evaluation of antimicrobial efficacy of QMix™ 2 in 1, sodium hypochlorite, and chlorhexidine against Enterococcus faecalis and Candida albicans.

AIM/OBJECTIVE: The aim of this study is to compare the antimicrobial efficacy of QMix™ 2 in 1, sodium hypochlorite (NaOCl), and chlorhexidine (CHX) against Enterococcus faecalis and Candida albicans. MATERIALS AND METHODS: Eighty freshly extracted, single-rooted human mandibular premolar teeth were instrumented and autoclaved. Samples were divided into two groups of 40 teeth each based on the type of microorganism used. Group I was inoculated with E. faecalis and Group II with C. albicans and incubated for 3 days. Each group was subdivided into four subgroups based on the type of irrigant used. Group IA, IIA, 5.25% NaOCl; Group IB, IIB, 2% CHX; Group IC, IIC, QMix™ 2 in 1; and Group ID, IID, 0.9% saline (the control group). Ten microliters of the sample from each canal was taken and was placed on Brain Heart Infusion agar and Sabouraud dextrose agar. The plates were incubated at 37°C for 24 h and colony forming units (CFUs) that were grown were counted. Data was analyzed with analysis of variance (ANOVA) followed by post-hoc Games-Howell test. RESULTS: The greatest antimicrobial effects were observed in samples treated with QMix™ 2 in 1 (P < 0.001). No statistical significant difference was found between 5.25% NaOCl and 2% CHX (P > 0.001) against E. faecalis and C. albicans. CONCLUSION: QMix™ 2 in 1 demonstrated significant antimicrobial efficacy against E. faecalis and C. albicans.

A simplified etching technique to improve the adhesion of fiber post.

PURPOSE: Numerous methods were used to etch the fiber posts to improve its bonding to root canal dentin. Our aim was to evaluate the efficacy of 37% phosphoric acid in etching fiber posts in comparison with 24% hydrogen peroxide. MATERIALS AND METHODS: Ninety human maxillary central incisors were taken and post space preparation was done. Ninety fiber posts were taken and divided into three groups (n=30) based on the surface treatment they received (H3PO4, H2O2, distilled water) and each group was further divided (n=10) based on the time period of application (15 seconds, 30 seconds, 60 seconds). All the posts were luted into canals using Rely X UniCem-2. Each tooth was then sectioned into six slices and subjected to push out test. Data obtained was subjected to statistical analysis at P<.05. The surface topography was evaluated using scanning electron microscopy. RESULTS: Highest bond strength values were noted in 15 seconds etched phosphoric acid group and 60 seconds etched hydrogen peroxide group with no significant difference between two groups. Surface topography revealed complete epoxy layer removal with no damage to its structural integrity in those groups. CONCLUSION: H3PO4 etching for a period of 15 seconds is an effective alternative in improving the adhesion of fiber post to root dentin.

"Dentinal microcracks after root canal preparation" a comparative evaluation with hand, rotary and reciprocating instrumentation.

INTRODUCTION: The purpose of this study was to compare the incidence of dentinal micro cracks after instrumentation with various types of NiTi files in rotary and reciprocating motion. MATERIALS AND METHODS: One hundred human extracted mandibular central incisors were taken and divided into 10 groups (n=10 teeth per group). Group 1- No preparation, Group 2 - Hand instrumentation, Groups 3,4 - ProTaper files in rotary and reciprocating motion, Groups 5,6 - ProTaper Next files in rotary and reciprocating motion, Groups 7,8 - Oneshape files in rotary and reciprocating motion, Groups 9,10 - Reciproc files in rotary and reciprocating motion. Specimens were sectioned horizontally at 3,6 and 9 mm from the apex and dentinal micro cracks were observed under a stereomicroscope. RESULTS: There was a statistically significant difference between the groups (p<0.05). There were no significant differences in crack formation between the groups (Protaper Next - Rot, Protaper Next - Rec, Reciproc - Rec); (ProTaper - Rot, ProTaper - Rec, Oneshape - Rot), (Oneshape - Rot, Reciproc - Rot), (One shape Reciproc, Reciproc - Rec); (p >.05). CONCLUSION: Least cracks were seen in canals instrumented with Pro Taper Next files both in rotary and reciprocating motion. Full sequence rotary systems showed less cracks than single file systems and full sequence rotary systems showed less cracks in reciprocating motion than in rotary motion.

Assessment of the wetting behavior of three different root canal sealers on root canal dentin.

AIM: The objective of the present study was to evaluate and compare the wetting behavior of three different root canal sealers on the root canal dentin surface treated with irrigants and their combination. MATERIALS AND METHODS: Decoronation and apical third resections of 27 extracted single-rooted human mandibular premolars were done. The roots were then split longitudinally into two halves, and randomly assigned into three treatment groups (n=18). The root dentin surfaces in Group1, Group 2 and Group 3 were treated with 17% ethylene diamine tetra acetic acid (EDTA), 3% sodium hypochlorite (NaOCl) and combination of 17% EDTA and 3% NaOCl, respectively. Each group was subdivided into three subgroups of 6 specimens each, depending on the the sealer used, i.e. sub group A. zinc oxide (ZnOE), sub group B. AH plus, subgroup C. Guttaflow sealer, respectively. The contact angle was measured using First Ten Angstroms (FTA) 200 dynamic contact angle analyzer. RESULTS: The contact angle values for AH Plus sealer were significantly lower when compared to the other two sealer groups. CONCLUSION: The wettability of AH Plus sealer on the root surface dentin was found to be better than Gutta-Flow and ZnOE sealer.