Microleakage beneath ceramic and metal brackets photopolymerized with LED or conventional light curing units.

OBJECTIVE: To test the null hypotheses that (1) the type of light curing unit used (quartz-tungsten-halogen [QTH] or light-emitting diode [LED]) would not affect the amount of microleakage observed beneath brackets, and (2) the bracket type used (ceramic or metal) would not influence the amount of microleakage observed beneath brackets. MATERIALS AND METHODS: 40 freshly-extracted human premolars were randomly assigned into 4 bonding groups (n = 10/group): group 1, metal bracket + LED-cured Transbond XT; group 2, ceramic bracket + LED-cured Transbond XT; group 3, metal bracket + QTH-cured Transbond XT; and group 4, ceramic bracket + QTH-cured Transbond XT. The teeth were kept in distilled water for 1 month, and thereafter subjected to 500 thermal cycles. Then, specimens were sealed with nail varnish, stained with 0.5% basic fuchsin for 24 hours, sectioned, and photographed under a stereomicroscope. Microleakage was scored with regard to the adhesive-tooth interface and the bracket-adhesive interface at both incisal and gingival margins. Statistical analysis was accomplished by Kruskal-Wallis and Mann-Whitney U-tests with Bonferroni correction. RESULTS: Microleakage was observed in all groups. When an LED curing unit was used for adhesive polymerization, ceramic brackets displayed significantly less microleakage than metal brackets in both tooth-adhesive and bracket-adhesive interfaces. When a QTH curing unit was used, ceramic brackets displayed significantly less microleakage than metal brackets in the bracket-adhesive interface in both gingival and incisal margins. CONCLUSIONS: Ceramic brackets cured with LED units were the best combination, demonstrating the lowest microleakage scores.

Microleakage beneath ceramic and metal brackets bonded with a conventional and an antibacterial adhesive system.

OBJECTIVE: To assess microleakage of a tooth-adhesive-bracket complex when metal or ceramic brackets were bonded with a conventional and an antibacterial self-etching adhesive. MATERIALS AND METHODS: Forty freshly extracted human premolars were randomly assigned to four equal groups and received the following treatments: group 1 = Transbond XT + metal bracket, group 2 = Transbond XT + ceramic bracket, group 3 = Clearfil Protect Bond + ceramic bracket, and group 4 = Clearfil Protect Bond + metal bracket. After photopolymerization, the teeth were kept in distilled water for 1 month and thereafter subjected to thermal cycling (500 cycles). Specimens were further sealed with nail varnish, stained with 0.5% basic fuchsin for 24 hours, sectioned and examined under a stereomicroscope, and scored for marginal microleakage for the adhesive-tooth and bracket-adhesive interfaces from incisal and gingival margins. Statistical analysis was accomplished by Kruskal-Wallis test and Mann-Whitney U-test with Bonferroni correction. RESULTS: All groups demonstrated microleakage between the adhesive-enamel and bracket-adhesive interfaces. A significant difference was observed among all groups (P < .05) for the microleakage between the bracket-adhesive interface. Metal brackets exhibited significantly more microleakage than did ceramic brackets between the bracket-adhesive interface with either of the adhesives. Clearfil Protect Bond exhibited results similar to Transbond XT. Clearfil Protect Bond may be a choice of adhesive in bracket bonding because of its antibacterial activity and similar microleakage results with the orthodontic adhesive. CONCLUSIONS: Metal brackets cause more leakage between an adhesive-bracket interface, which may lead to lower clinical shear bond strength and white-spot lesions.

Effects of laser treatment on endodontic pathogen Enterococcus faecalis: a systematic review.

OBJECTIVE: The effects of laser on eradication of Enterococcus faecalis in the root canal are unclear. The purpose of this review was to explore the antimicrobial effects of laser radiation on E. faecalis. METHODS: Using the combined search terms root canal, laser, antimicrobial, as inclusion and exclusion criteria, eligible articles were retrieved from PubMed, Embase, and OVID by hand searching. The initial search yielded 4192 titles, and 162 articles were assigned to full text analysis. Upon classification of the data with regard to laser source, laser energy level and watt, duration of application, initial and final bacterial count, and rate of decrease in bacteria, p values were pooled and data were calculated using Fisher's Z method. The initial and final bacterial count, the standard deviation of data, and data expressed in logarithm were pooled and calculated using standardized difference in means method. In the event homogeneity was found between studies, the outcome of the fixed effect model was used, and if heterogeneity was found, the result of the random effect model was used. RESULTS: A total of 12 articles were included. Er, Cr:YSGG, Nd:YAG, and KTP lasers and 1 and 1.5 W energy levels significantly reduced E. faecalis count. CONCLUSIONS: Despite the limited number of publications, the outcome of present meta-analytical assessment suggests that lasers are effective in eradication of E. faecalis.

A randomized, prospective, open-ended clinical trial of zirconia fixed partial dentures on teeth and implants: interim results.

PURPOSE: The aim of this randomized controlled clinical trial was to compare the outcomes of zirconia crowns and fixed partial dentures (FPDs) supported by teeth or implants. MATERIALS AND METHODS: Patients were recruited based on inclusion/exclusion criteria, and 59 eligible subjects were assigned randomly to treatment by one of four zirconia systems (Cercon, ZirkonZahn, Lava, and Katana). One hundred seven single-tooth and 160 three- to six-unit FPDs were fabricated on teeth and implants and cemented using composite resin cement. Californian Dental Association (CDA) quality evaluation, Plaque Index, and Gingival Index scores were recorded, and radiographic assessment of the restorations was performed using periapical and panoramic radiographs at baseline and annually up to 4 years. RESULTS: Five failures (1.9%) were recorded. The 4-year Kaplan-Meier survival probabilities of FPDs were higher than those of single-tooth restorations (P = .046). The highest survival probability for crowns was observed for Katana and the lowest for Cercon (P < .05). For FPDs, the survival probabilities of Lava restorations were similar to those of Cercon but lower than those of ZirkonZahn and Katana (P < .05). The 4-year survival probabilities of implant- and tooth-supported crowns were comparable (P = .182). Regarding CDA ratings, the slight marginal discrepancy scores for the Cercon restorations were higher than for the other systems at 1 year (P < .05). In FPDs, 94.5% of Katana FPDs had slight or gross color mismatch scores, and the difference between color and surface ratings among zirconia systems was significant (P < .05). FPDs had better periodontal scores than crowns over the 4-year observation period (P < .05). CONCLUSION: The 4-year interim results of this study suggest that zirconia systems used to fabricate FPDs have predictably high survival rates on teeth and implants and may exhibit differences, particularly in terms of mechanical failures, marginal adaptation, and color matching.

Effect of LED curing on marginal integrity of an ormocer-based sealant.

PURPOSE: The purpose of this study was to investigate the microleakage of a light cured, ormocer-based fissure sealant when photopolymerized with 2 different light emitting diode (LED) curing units and a conventional quartz-tungsten halogen (QTH) light-curing unit. METHODS: Thirty freshly extracted, unerupted human third molars from 9 adolescent were randomly assigned into 3 groups (N=10/group). Pits and fissures were acid etched for 30 seconds, rinsed for 15 seconds with an air-water spray, and air-dried. An ormocer-based fissure sealant material (Admira Seal) was applied to all fissures. In group 1, the sealant was photopolymerized with a Smart Light LED curing unit (Dentsply) for 10 seconds. Another LED curing unit (Elipar II) and a conventional QTH curing unit (Hilux) were used in groups 2 and 3 for 10 and 30 seconds, respectively. Specimens were immersed in 0.5% basic fuchsin for 24 hours, sectioned and examined under a stereomicroscope, and scored for marginal microleakage. RESULTS: Statistical analysis of microleakage scores revealed no significant difference among the groups tested (P>.05, Kruskal-Wallis test). CONCLUSION: The tested LED curing units may provide reduction in total application time without comprising marginal integrity of the ormocer-based sealant.