• Restorative Dentistry and Endodontics
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• v.47 no.2
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• pp.21.1-21.11
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• 2022

Objectives: This study aimed to investigate the bonding effects of cleaning protocols on dentin impregnated with endodontic sealer residues using ethanol (E) or xylol (X). The effects of dentin acid etching immediately (I) or 7 days (P) after cleaning were also evaluated. For bonding to dentin, universal adhesive (Scotchbond Universal; 3M ESPE) was used. The persistence of sealer residues, hybrid layer formation and microshear bond strength were the performed analysis. Materials and Methods: One hundred and twenty bovine dentin specimens were allocated into 4 groups (n = 10): G1 (E+I); G2 (X+I); G3 (E+P); and G4 (X+P). The persistence of sealer residues was evaluated by SEM. Confocal laser scanning microscopy images were taken to measure the formed hybrid layer using the Image J program. For microshear bond strength, 4 resin composite cylinders were placed over the dentin after the cleaning protocols. ANOVA followed by Tukey test and Kruskal-Wallis followed by Dunn test were used for parametric and non-parametric data, respectively (α = 5%). Results: G2 and G4 groups showed a lower persistence of residues (p < 0.05) and thicker hybrid layer than the other groups (p < 0.05). No bond strength differences among all groups were observed (p > 0.05). Conclusions: Dentin cleaning using xylol, regardless of the time-point of acid etching, provided lower persistence of residues over the surface and thicker hybrid layer. However, the bond strength of the universal adhesive system in etch-and-rinse strategy was not influenced by the cleaning protocols or time-point of acid etching.

• The Journal of Advanced Prosthodontics
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• v.9 no.2
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• pp.110-117
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• 2017

PURPOSE. This laboratory study assessed the effect of different dentin cleaning procedures on shear bond strength of resin cements for recementing prosthesis. MATERIALS AND METHODS. A $4{\times}4$ flat surface was prepared on the labial surface of 52 maxillary central incisors. Metal frames ($4{\times}4{\times}1.5mm$) were cast with nickel-chromium alloy. All specimens were randomly divided into 2 groups to be cemented with either Panavia F2.0 (P) or RelyX Ultimate (U) cement. The initial shear bond strength was recorded by Universal Testing Machine at a crosshead speed of 0.5 mm/min. Debonded specimens were randomly allocated into 2 subgroups (n = 13) according to the dentin cleaning procedures for recementation. The residual cement on bonded dentin surfaces was eliminated with either pumice slurry (p) or tungsten carbide bur (c). The restorations were rebonded with the same cement and were subjected to shear test. Data failed the normality test (P < .05), thus were analyzed with Mann Whitney U-test, Wilcoxon signed rank test, and two-way ANOVA after logarithmic transformation (${\alpha}=.05$). RESULTS. The initial shear bond strength of group P was significantly higher than group U (P = .001). Pc and Uc groups presented higher bond strength after recementation compared to the initial bond strength. However, it was significant only in Pc group (P = .034). CONCLUSION. The specimens recemented with Panavia F2.0 provided higher bond strength than RelyX Ultimate cement. Moreover, a tungsten carbide bur was a more efficient method in removing the residual resin cement and increased the bond strength of Panavia F2.0 cement after recementation.

• Restorative Dentistry and Endodontics
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• v.13 no.1
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• pp.123-129
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• 1988

The purpose of this study was to evaluate the bond strength of glassionomer cement against cut dentin surface which was treated with various surface cleaning agents. 48 freshly extracted human 3rd molars were ground flat through the enamel into the dentin using 600 grit silicone carbide paper under a flow of water. The were divided into four groups by the following cleaning procedure on cut dentin surface; Group I : No surface treatment after grinding with 600 grit silicone carbide paper as control group Group II : Surface treatment with 50% citric acid for 30 seconds. Group III : Surface treatment with 37% phosphoric acid for 30 seconds. Group IV : Surface treatment with 10% poly acrylic acid for 30 seconds. The specimens in 4 groups were immersed in distilled water at $37^{\circ}C$ for 24 hours before testing after cleanising with water-spray and drying with air. Bond strength was measured with Instron Universal Testing Machine (Autograph S-100, Shimadzu, Kyoto, JAPAN). The results were as follows: 1. The bond strengths of group II, III & IV were not seemed to be shown more significant improvement than a group I. 2. The bond strengths in groups which were treated with 50% citric acid, 37% phosphoric acid and 10% polycrylic acid, were ranked 24.70kg/$cm^2$, 22.02kg/$cm^2$ and 31.13kg/$cm^2$, but its difference was not significant, statistically.

• Korean Journal of Dental Materials
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• v.43 no.1
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• pp.17-28
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• 2016

The aim of this study was to evaluate the changes in dentinal permeability after application of dentin desensitizer on exposed dentin immediately after ultrasonic scaling to teeth with non-carious cervical lesions. Thirty caries-free extracted molars were fixed to slide glasses after horizontally being sectioned at 5 mm below the cemento- enamel junction (CEJ). The prepared specimen was connected to a fluid flow measuring device (nano-Flow), and a V-shaped cavity was formed at the CEJ to imitate the non-carious cervical lesion. After no fluid leakage was confirmed in the connected system with specimen, tooth surface was treated ultrasonic cleaning with piezoelectric ultrasonic scalers until dentinal tubules were exposed. And 6 different desensitizers were applied on exposed dentin. Real-time measurements of dentinal fluid flow were performed during ultrasonic scaling and application of dentin desensitizer. To evaluate the occlusion of exposed dentinal tubules, tooth surface was examined by SEM. Following results were observed. After ultrasonic scaling, more dentinal tubules were exposed on the tooth with non-carious cervical lesions compared to tooth without lesions. The rate of fluid flow measured with nano-Flow system had correlation with the degree of dentin occlusion observed with SEM after application of desensitizers on exposed dentin. Desensitizers with glutaraldehyde and HEMA did not decrease the rate of fluid flow and did not show dentin occlusion. Desensitizers with oxalate showed the limited effects on the rate of fluid flow and dentinal tubule occlusion. Desensitizer with resin monomer showed the significant effect on the rate of fluid flow and dentin occlusion.

• The Journal of Advanced Prosthodontics
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• v.6 no.2
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• pp.79-87
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• 2014

PURPOSE. The aim of this study was to determine the efficiency of Erbium, Chromium: Yttrium-Scandium-Gallium-Garnet laser in different output powers for removing permanent resin cement residues and therefore its influence on microshear bond strength compared to other cleaning methods. MATERIALS AND METHODS. 90 extracted human molars were sectioned in 1 mm thickness. Resin cement was applied to surface of sliced teeth. After the removal of initial cement, 6 test groups were prepared by various dentin surface treatment methods as follows: no treatment (Group 1), ethylene diamine tetra acetic acid application (Group 2), Endosolv R application (Group 3), 1.25 W Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet laser irradiation (Group 4), 2 W Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet laser irradiation (Group 5) and 3.5 W Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet laser irradiation (Group 6). The topography and morphology of the treated dentin surfaces were investigated by scanning electron microscopy (n=2 for each group). Following the repetitive cementation, microshear bond strength between dentin and cement (n=26 in per group) were measured with universal testing machine and the data were analyzed by Kruskal Wallis H Test with Bonferroni correction (P<.05). Fracture patterns were investigated by light microscope. RESULTS. Mean microshear bond strength ${\pm}$ SD (MPa) for each group was $34.9{\pm}17.7$, $32.1{\pm}15.8$, $37.8{\pm}19.3$, $31.3{\pm}12.7$, $44.4{\pm}13.6$, $40.2{\pm}13.2$ respectively. Group 5 showed significantly difference from Group 1, Group 2 and Group 4. Also, Group 6 was found statistically different from Group 4. CONCLUSION. 2 W and 3.5 W Erbium, Chromium: Yttrium-Scandium-Gallium-Garnet laser application were found efficient in removing resin residues.

• Proceedings of the KACD Conference
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• 2003.11a
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• pp.608-608
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• 2003

The main objectives of root canal therapy are cleaning and shaping and then obturating the root canal system in 3 dimensions to prevent reinfection. Many instrumentation techniques and devices, supported by an irrigation system capable of removing pulp tissue remnants and dentin debris, have been proposed to shape root canals. But current regimens in chemomechanical debridement using instrumentation and irrigation with NaOCl are not predictably effective in root canal disinfection. These findings are not surprising because the root canal system is complex and contains numerous ramifications and anatomical irregularities. The microorganisms in root canals not only invade the anatomic irregularities of the root canal system but also are present in the dentinal tubules. Therefore further disinfection with an effective antimicrobial agent may be necessary and it well1mown that use of intracanal medication will lower bacterial count in infected root canals. Calcium hydroxide has a long history of use in endodontics, and more attention has been given to the use of calcium hydroxide as intracanal dressing for the treatment of infected pulp. However, when treatment is completed in one visit, no intracanal medications other than intracanal irrigants are used. Recently, a mixture of a tetracycline isomer, an acid, and a detergent(MTAD), has been introduced as a final rinse for disinfuction of the root canal system. It has been shown that MTAD is able to remove the smear layer with minimal erosive changes on the surface of dentin, and is effective against Enterococcus faecalis, a microorganism resistant to the action of other antimicrobial medications. In another study, the ability of MTAD was investigated to disinfect contaminated root canals with whole saliva and compared its efficacy to that of NaOCl Based on the results, it seems that MTAD is significantly more effective than 5.25% NaOCl in eradicating bacteria from infected root canals. In the cytotoxicity evaluation, MTAD is less cytotoxic than engenol, 3% $H20_2,\;Ca(OH)_2$ paste, 5.25% NaGCl, Peridex, and EDTA and more cytotoxic than 2.63%,1.31% and 0.66% NaOCl. Is it promising or transient?