Effect of delayed light-curing on solubility, color stability, and opacity of Fuji II LC glass ionomer cement: original article / Efeito da fotopolimerização tardia na solubilidade, estabilidade de cor e opacidade do cimento de ionômero de vidro Fuji II LC: artigo original

Objective: Resin-modified glass ionomer (RMGI) cements are among the commonly used restorative materials in low stress-bearing areas and also for temporary restorations. The competition between acid-base reactions and light polymerization reactions in delayed curing of RMGIs can affect their physical and mechanical properties, as well as their degree of conversion. Since solubility, color stability, and opacity are among the main physical properties affecting the durability and clinical service of RMGI restorations, this study aimed to assess the effect of delayed curing on solubility, color stability, and opacity of Fuji II LC RMGI. Material and Methods: This in vitro, experimental study evaluated 80 Fuji II LC RMGI specimens (10 specimens per each in 4 groups) in terms of solubility, color stability, and opacity at 6 months later. Specimens were cured immediately or were cured with 1, 5 and 10 min delay. Results: Maximum solubility and minimum change in opacity and color stability at 6 months were noted in the group with delayed curing by 10 min. A significant difference was noted in the solubility of specimens cured after 10 min and 1 min. Significant differences were also noted in the opacity and color stability of specimens cured after 10 min and all other groups (P < 0.05). Conclusion: Delayed curing by 1 min decreased the solubility of RMGI specimens compared with immediate curing or curing after 5 min. Although this difference did not reach statistical significance. Color stability and changes in opacity are mainly influenced by the acid-base reactions rather than polymerization reactions.(AU)

Objetivo: Cimentos de ionômero de vidro modificado por resina (CIVMR) estão entre os materiais restauradores mais comumente utilizados em áreas de baixa tensão e também para restaurações temporárias. A competição entre reações ácido-base e reações provenientes da fotopolimerização tardia dos CIVRMs podem afetar suas propriedades físicas e mecânicas, bem como seu grau de conversão. Uma vez que a solubilidade, estabilidade de cor e opacidade estão entre as principais propriedades físicas que afetam a durabilidade e o tempo de serviço clinico de restaurações de CIVMR, este estudo teve como objetivo avaliar o efeito da fotopolimerizaçao tardia na solubilidade, estabilidade de cor e opacidade do CIVMR Fuji II LC. Material e Métodos: Este estudo experimental in vitro avaliou 80 espécimes de CIVMR Fuji II LC (4 grupos com 10 espécimes cada) em termos de solubilidade, estabilidade de cor e opacidade apos 6 meses. As amostras foram fotopolimerizadas imediatamente ou com 1, 5 e 10 min de atraso. Resultados: Máxima solubilidade e mínima alteração na opacidade e estabilidade da cor em 6 meses foram observadas no grupo com fotopolimerização tardia em 10 min. Uma diferença significativa foi observada na solubilidade das amostras fotopolimerizadas após 10 min e 1 min. Diferenças significativas também foram observadas na opacidade e estabilidade de cor das amostras fotopolimerizadas após 10 min e em todos os outros grupos (P <0,05). Conclusão: A fotopolimerizaçao tardia em 1 min diminuiu a solubilidade das amostras CIVMR em comparação com a fotopolimerizaçao imediata ou após 5 min. Embora essa diferença não tenha alcançado significância estatística. A estabilidade da cor e as mudanças na opacidade são influenciadas principalmente por reações ácido-base, em vez de reações causadas pela polimerização(AU)

Comparative Evaluation of Sealing Ability of Newer Materials Used As Dentin Substitutes in Class II Sandwich Restorations: An In Vitro Study

Introduction: Even with the advances and innovations inrestorative dentistry, microleakage is regarded one of the mainproblems in this area.Objective: To evaluate in vitro marginal microleakage ofBiodentine, Fuji II LC and SDR at the cervical level and at theinterface these materials with Tetric N Ceram Bulk fillcomposite and also to note the marginal microleakage whenthese materials were used as bulk fill materials.Materials and Methods: Cavities, standardized on the mesialand distal surfaces, were prepared in thirty molars andrandomly assigned to two groups (n = 30), according to themode of restoration done.Goup1 (control) in which testmaterials were used as bulk fill. These were further subdividedinto subgroups according to the material. SG1: Biodentine(SEPTODONT); SG2: Fuji II LC (GC); SG3: SDR (Dentsply).Group2 (experimental) in which test materials used as dentinsubstituent in class II sandwich technique followed byrestoration with Tetric N Ceram (Ivoclar vivadent). These werealso divided into subgroups, SG4: Biodentine + Tetric NCeram; SG5: Fuji II LC + Tetric N Ceram; SG6: SDR + Tetric NCeram. After storage for 24 hours in an incubator (37 °C), thesamples were submitted to the thermocycling test (500 cycles:5 °C/55 °C). They were later waterproofed, immersed in 1%methylene blue solution and sectioned in the mesialdistal direction for evaluation under stereomicroscope at 30xmagnification (Nikon SMZ 1500 Zoom Stereomicroscope)Scores from 0 to 3 using the ISO microleakage scoring system(ISO/TS 11405:2003). The ANOVA Test and Post- hoc Test,with a significance level of 5%, were used for statisticalanalysis.Conclusion: The study concluded that SDR (SD 2.38) showedthe least amount of microleakage both at the occlusal and atthe cervical levels in open sandwich restorations and alsowhen used as bulk fill materials as compared with Biodentine(SD 1.73) and Fuji II LC (SD 1.00).

Evaluation of the leakage of bleaching materials through different bases into the root canal filling: an invitro study

AIM: The purpose of this study was to evaluate the leakage of bleaching agents through 3 different bases into the obturated pulp space and dentinal tubules in intra coronal bleaching. MATERIAL AND METHODS: Fifty-five freshly extracted, intact non-carious single rooted teeth were collected and stored in formalin until used. The specimen divided into experimental and control group. Experimental group were further subdivided into 3 subgroups on the base of cervical base materials. Group I was Type II GIC, Group II was Fuji II LC and Group III was Hybrid composite. The control groups was divides into negative group (received the bleaching agent and received complete external coating including access cavity) and positive control group (did not receive any external coating). The obturated pulp space were removed at a level of 3 mm below the cemento enamel junction and filled with dry cotton pellets and temporized with temporary cement, stored at ± 37°C and 100% relative humidity for five days, the bleaching material were placed in the pulp chamber (a paste of sodium perborate i.e. 0.15g and 30% hydrogen peroxide 0.05ml), and then stored for 3 days in an incubator. Later on the teeth were immersed in India ink dye and stored at ± 37°C and 100% relative humidity for 5 days. Specimens were examined under binocular microscope with a stage micrometer to analyze the degree of dye penetration. RESULTS: The minimal leakage values were observed with type II glass ionomer cement followed by light cure glass ionomer cement and lastly by hybrid composite. CONCLUSION: The present invitro investigation evaluated the microleakage observed with different cervical base materials during non-vital bleaching procedures.