Browsing by Subject "Microleakage"

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    The effect of pit and fissure morphology and sealant viscosity on sealant penetration and microleakage
    (2017) Zawam, Omelkher Muftah; Soto, Armando E.; Hara, Anderson T.; Cook, Norman Blaine
    Background: The ability of sealants to prevent caries is directly related to the sealant being retained in teeth. The longer the material remains bonded to the occlusal surface, the more protection it provides to the tooth. Objective: The aim of this in-vitro study was to evaluate the influence of pit and fissure morphologies and sealant viscosity on sealant penetration and micro-leakage. 82 Study Hypothesis: The low viscosity dental sealant will express better penetration ability and less microleakage in permanent molars with any pit and fissure morphology than the high viscosity sealant. Material and methods: Permanent extracted molars (n = 150) were distributed into two groups based on two types of sealant (high and low viscosity) Permanent extracted molars (n = 150) were selected using the International Caries Detection Assessment system (ICDAS) criteria 0-1. Teeth were stored in 0.1-percent thymol and distilled water. Teeth were assigned to three subgroups according to the fissure’s morphology. Enamel was etched with 35-percent phosphoric acid for 30 seconds; two different light cured sealants were placed, Group A: Delton and Group B: Ultra X Plus. Specimens were thermocycled for 500 cycles between two water baths, having a 40°C temperature differential (4°C to 48°C). Teeth were coated with nail varnish and wax, except in the occlusal areas. All specimens were immersed in 1-percent methylene blue dye at 37°C for 24 hours. Specimens were sectioned longitudinally in a bucco-lingual direction, and the sections were photographed and analyzed by a previously trained examiner for fissure morphology, sealant penetration, and microleakage using a standardized grading system. Data were entered and statistically analyzed, at the 5-percent significance level. Results: Viscosity of sealant and morphology of fissures had significant effects on sealant penetration (p < 0.001). The interaction between viscosity of sealant and morphology of fissures was not significant (p = 0.4236). The sealant penetration for Delton was significantly higher than the UltraSeal XT Plus (p < 0.0001). The sealant penetration for fissure I-type was significantly lower than fissures U and V-types (p < 0.0001). Sealant penetration for Y-type was significantly lower than U and V-types (p < 83 0.0001). However, the viscosity of sealant and morphology of fissures did not have significant effect on microleakage (p = 0.5891 and p = 0.4857). The interaction between the viscosity of the sealant material and the morphology of pit and fissures was not significant (p = 0.6657). Conclusion: The results of the present study indicated the viscosity of the sealant and the morphology did not affect the microleakage. On the other hand, the viscosity of sealant affected the penetration ability of dental sealant. The low viscosity dental sealant (Delton) exhibited a better penetration than the high viscosity sealant (UltraSeal XT Plus). As the morphology of pit and fissure directly affected the penetration ability, the fissures types U and V exhibited a better penetration than fissure types Y and I.
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    Microleakage in new resin-modified glass ionomer cements using new no-rinse conditioners : an in-vitro study
    (2012) Patel, Ashish G.; Cook, Norman Blaine, 1954-; Bottino, Marco C.; Cochran, Michael A. (Michael Alan), 1944-; Matis, Bruce A.; Hara, Anderson T.
    Since their introduction in 1970, glass ionomer cements have been used in a wide variety of clinical situations in dentistry. The main advantages of glass ionomer cements are chemical bonding, fluoride release and uptake, excellent seal against microleakage, and biocompatibility. The main objective of this study was to compare the microleakage of two new paste-paste glass ionomer systems to their traditional RMGIC counterparts when conditioning the dentin with newly developed no-rinse conditioners or polyacrylic acid. Materials and methods: Standardized cavity preparations were made, centered on the cementoenamel junction of the buccal surface, on 96 extracted human molars divided in 8 groups (n = 12). G1 Ketac Nano with Ketac Nano Primer, G2 Ketac Nano with Ketac Conditioner, G3 Photac Fil with Ketac Nano Primer, G4 Photac Fil with Ketac Cavity Conditioner, G5 Fuji Filling LC with GC Self Conditioner, G6 Fuji Filling LC with GC Cavity Conditioner, G7 Fuji II LC with GC Self Conditioner, G8 Fuji II LC with GC Cavity Conditioner. The cavities were treated with either a no-rinse or polyacrylic acid conditioner and restored with a paste-paste RMGIC or traditional RMGIC from the same manufacturer (n =12). The teeth were then sealed to within 2 mm of the restoration margins and thermocycled. The teeth were immersed in 2.0-percent methylene blue and stored at room temperature for 24 hours. Then, the teeth were be embedded in resin and sectioned longitudinally in a buccolingual direction making 1 section (1 mm thick) per tooth. The occlusal and gingival restoration margins of each specimen were examined with a stereomicroscope at X10 magnification to determine the degree of microleakage. Results: Mixed-model ANOVA was used to test the fixed effect of the eight groups and cervical vs. occlusal location within each tooth sample on microleakage, with sample as the random effect. Both main effects and the interaction are significant, p < 0001 for both group and location effects, and p = 0.0013 for the interaction of group and location. The cervical interface showed more microleakage in all groups except group 8 where microleakage was the same as at the occlusal margin. No significant difference was observed among groups for microleakage at the occlusal interface. There was significant difference among groups at the cervical interface with Fuji II LC using GC Cavity Conditioner performing best. For the occlusal interface Group 4 performed the best and Group 2 performed the worst, although the difference was not significant among the groups. For the cervical interface, Group 8 performed the best followed by Group 3, Group 4 and Group 6, although these four groups were not significantly different. For the cervical interface, group 2 performed the worst followed by group 1. Based on these results we can conclude that, overall, traditional RMGIC with polyacrylic acid conditioning performed better than the new paste-paste RMGIC systems utilizing the no-rinse conditioners.
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    Microtensile Bond Strength and Microleakage of HEMA-Free One-Step Self-Etch Adhesive
    (Office of the Vice Chancellor for Research, 2013-04-05) AlZain, Afnan; Eckert, George; Platt, Jeffrey A.
    This study evaluated the microtensile dentin bond strength (μ-TBS) and microleakage of a one-step HEMA-free self-etch adhesive (G-aenial Bond-GB) compared to a 2-step self-etch (Clearfil SE-SE) and a 3-step etch and rinse (OptiBond FL-OB) adhesive with and without pre-etching with phosphoric acid. Human molars were divided randomly into 5 groups (n=15), GB and SE (without pre-etching), GB+ and SE+ (with pre-etching), and OB. Eight beams were obtained from each tooth and half of the beams were subjected to μ-TBS testing after 2d. The remaining beams were thermocycled (2,500 cycles), aged for 40d and subjected to μ-TBS testing using a universal testing machine. Failures were analyzed using light microscopy and SEM. Similar groups were used for the microleakage test (n=11). Class V cavities were prepared on the buccal and lingual surfaces of each molar. Teeth were thermocycled (2,500 cycles), aged for 40d, soaked in 1% methylene blue dye for 24h, and sectioned longitudinally from the facial to lingual surface. The dye penetration was scored using light microscopy and an ordinal scale from 0-3. Data was analyzed using Weibull, GEE, and Wilcoxon Rank Sum tests (α=0.05). Phosphoric acid pre-etching significantly increased dentin bond strength. After 40d, the mean bond strength ranged from 28.6-45.7 MPa with a statistical significance of GB, SE