Assessment of Microleakage of Class V Composite Resin Restoration Following Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) Laser Conditioning and Acid Etching with Two Different Bonding Systems

INTRODUCTION: The use of laser for cavity preparation or conditioning of dentin and enamel surfaces as an alternative for dental tissue acid-etch have increased in recent years. The aim of this in vitro study was to compare microleakage at enamel-composite and dentincomposite interfaces following Erbium-Doped Yttrium Aluminum Garnet(Er:YAG) laser conditioning or acid-etching of enamel and dentin, hybridized with different bonding systems.METHODS: Class V cavities were prepared on the lingual and buccal surfaces of 50 recently extracted intact human posterior teeth with occlusal margin in the enamel and gingival margin in the dentin. The cavities were randomly assigned to five groups: group1:conditioned with laser (Energy=120mJ, Frequency=10Hz, Pulse duration=100μs for Enamel and Energy=80mJ, Frequency=10Hz, Pulse duration=100μs for Dentin) + Optibond FL, group2:conditioned with laser + etching with 35% phosphoric acid + Optibond FL, group3:conditioned with laser + Clearfil SE Bond, group 4 (control):acid etched with 35% phosphoric acid + Optibond FL, group 5 (control): Clearfil SE Bond. All cavities were restored using Point 4 composite resin. All samples were stored in distilled water at 37°c for 24 h, then were thermocycled for 500 cycles and immersed in 50% silver nitrate solution for 24 h. The teeth were sectioned bucco-lingually to evaluate the dye penetration. Kruskal-Wallis & Mann-Whitney tests were used for statistical analysis.RESULTS: In occlusal margins, the least microleakage showed in groups 2, 4 and 5. The maximum microleakage was observed in group 3 (P=0.009). In gingival margins, the least microleakage was recorded in group2, while the most microleakage was found in group 5 (P=0.001). Differences between 5 study groups were statistically significant (P<0.05). The microleakage scores were higher at the gingival margins.CONCLUSION: The use of the Er:YAG laser for conditioning with different dentin adhesive systems influenced the marginal sealing of composite resin restorations

Reaction of Rat Subcutaneous Connective Tissue to Resin Composites Polymerized with Different Light Curing Units and Different Lightening Methods

The aim of the study was to determine and compare the reaction of rat subcutaneous connective tissue to resin composites polymerized with different lights curing and lightening methods. In this in vivo study, 20 mature Wister Albino rats were used. The composite discs, 4 mm in diameter and 2 mm thick, were cured by QTH or LED light curing units with 4 different lightning methods (full power QTH, full power LED, pulse LED, and ramp LED). Five resin composite discs were implanted in each rat, so that 4 of 5 discs for implantation of cured composite discs differently and central one as control without implantation. After sacrificing at 7, 14, 30, and 60 days the inflammatory grade, fibrosis, and necrosis were determined. Freedman and Cochran tests were used to analyze the data using SPSS software ver. 15. The results of the study showed significant differences in inflammation grade and fibrosis among control group and 4 experimental groups at day 14 (P < 0.05). In necrosis, there was no significant difference among 4 groups in different times (P > 0.05). In conclusion, neither the type of light curing units (LED or QTH) nor the lightening methods can affect the grade of inflammatory reaction

Non-invasive management of fused upper incisors

The union of two different dental sprouts which can happen in any phase of dental development is commonly called fusion. This developmental anomaly may cause clinical problems including esthetic impairment, which are mainly treated by endodontic and surgical treatments. There are a few reports of conservative not invasive treatment of fused incisors teeth through restorative or prosthetic techniques. They are rarely reported in mandibular posterior teeth. This paper presents an unusual case of fusion of 7 and 8, and also 9 and 10 teeth which was treated with a nonendodontic and nonsurgical conservative approach. Patient was a healthy18-year-old female with chief complaint of bad-looking teeth that in intraoral examination revealed the fusion of 7 and 8, and also 9 and 10 teeth. The space between the mesial of the 6 and 11 teeth was reconstructed. Diastema between the fused teeth was closed. A new lateral tooth was replaced between the fused teeth (7 and 8) and 6 tooth with direct fiber-reinforced composite. The space between the fused teeth (9 and 10) and also tooth 11 was partially closed. Gingival papillas were reconstructed using pink composite. The mandibular anterior missing teeth were replaced with rochett bridge. At the end of treatment the esthetic of the patient was improved. As the treatment was not invasive, major complications are not expected; however, there is potential for eventual long-term periodontal problems due to poor oral hygiene. Debonding of the rochett bridge may happen as well

Recharge pattern of contemporary glass ionomer restoratives

Background: As glass ionomers have the ability to reload fluoride from outside sources, the aim was to compare the recharge pattern of six glass ionomer cements after exposure to fluoride. Materials and Methods: Fuji VII, Fuji IX, Riva Pink, Riva Bleach, Ketac Fil and Fuji IX Extra were investigated. The fluoride-containing materials used were tooth paste and mouth wash (Colgate). Specimens of each material (n=15) were immersed separately in deionized water for 59 days. Then the samples of each material were divided into three groups of five each. Two groups were recharged for 2, 20 and 60 min daily during three consecutive weekly intervals and then no treatment for one week. The third group was used as control. Fluoride release measurements (μg/cm 2 /day) were made in every 24 h. One-way and repeated measures analysis of variance tests were used. Results: Tooth paste recharged materials showed higher level of recharge. On day 1, the difference of fluoride release from different treatment groups of different materials except for Fuji IX Extra were not significant (P>0.05). On days 7 and 14, the differences observed were significant (P<0.05) for all materials except for Fuji VII (tooth paste versus mouth wash) and Trial Fuji IX (mouth wash versus control) and on day 14 for Rvia Pink (mouth wash versus control). On days 21 and 28, the differences observed were significant for all the materials (P<0.05) except for Riva Pink (toothpaste versus mouth wash), Riva Bleach, Ketac Fil and Trial FujiI X (mouth wash versus control) on day 28. Conclusion: A time tabled schedule of application of fluoride-containing materials could help to achieve high fluoride release