The influence of dentin depths on the shear bond strenghth of different adhesives under simulated pulpal pressure / 实用口腔医学杂志

Objective: To determine the shear bond strength of different adhesive systems to superficial and deep dentin under simulated pulpal pressure. Methods: Occlusal surfaces of 72 sound extracted noncarious human molars were ground to obtain flat dentin surfaces(36 superficial and 36 deep dentin). Each dentin groups was randomly asssigned into 3 groups(n = 12): Clearfil SE Bond(SE), Clearfil S3 Bond(S3) and Prime&Bond NT(PB). All of samples were tested under simulated pulpal pressure. After bonding procedures with 3 adhesives respectively,all samples were covered with nail vanishi. The shear bond strength was tested after the samples stored for 24 h under simulated pulpal pressure. Results: The bond strength of PB to superficial and deep was (17. 11 ± 2. 71) and(11. 13 ± 3. 60) MPa(P ＜ 0. 05),that of SE (16. 53 ± 5. 29) and (14. 78 ± 4. 53) MPa(P＞ 0. 05),S3 (9. 08 ± 1. 74) and (8. 43 ± 1. 41) MPa(P＞ 0. 05). Conclusion: Bond strengths of phosphoric acid etching system decreases with an increase of dentin depth, that of two-step self-etch adhesive system is not affected by the depth.

Influence of simulated pulpal pressure on the variation of intrapulpal temperature during adhesive system light-curing / Influência da pressão pulpar simulada na variação de temperatura intrapulpar durante a fotopolimerização do sistema adesivo

Objective: To evaluate the effects of simulated pulpal pressure (SPP) on the variation of intrapulpal temperature (T) during lightcuring of the adhesive system. Material and Methods: One hundred sound human molars were sectioned from the highest pulp horn to obtain a 2-mm of thickness dentin. The specimens were randomly divided into two groups: (n = 50), according to the presence or absence of SPP (15 cm H2 O). The specimens were sequentially treated as follows: 37% phosphoric acid (Scotchbond Universal; 3M/ESPE), adhesive system (Scotchbond Universal/3M ESPE) and light-curing (10 s). T was evaluated during adhesive lightcuring with a K-type thermometer put inside the pulp chamber. Data were analysed by using Mann-Whitney's test (at 5%). Results: According to Mann-Whitney's test, the absence group presented a T of 2 °C, whereas the presence group 1 °C. The mean values of T were 0.82 ± 0.56 °C for the presence group and 2.30±0.73 °C for the absence group. Conclusion: Simulated pulpal pressure significantly reduced the temperature rise in the pulp chamber during light-curing of the adhesive system, showing the importance of inserting this protocol of simulated pulpal pressure in the laboratory procedures.(AU)

Objetivos: Avaliar os efeitos da pressão pulpar simulada (PPS) na variação de temperatura (DT) durante a fotopolimerização do sistema adesivo. Material e Método: Cem molares humanos hígidos foram seccionados para obtenção de 2 mm de espessura de dentina, a partir do corno pulpar mais alto. As amostras foram divididas aleatoriamente em 2 grupos (n = 50): ausência e presença de PPS (15 cm de H2 O). As amostras foram tratadas seqüencialmente com: ácido fosfórico 37% (Scotchbond Universal; 3M/ESPE), sistema adesivo (Scotchbond Universal/3M ESPE), seguida da fotopolimerização (10 s). Na seqüência, um bloco de resina composta (Filtek Z350 XT; 3M/ESPE) foi confeccionado sobre a área preparada. Para a fotopolimerização, utilizou-se o fotopolimerizador LED Light Curing System - Demi Plus (Kerr Corporation, Middleton, WI, USA), com potência de 1200 mW/cm2 . A DT foi avaliada durante a fotopolimerização do adesivo por meio de um termômetro digital no interior da câmara pulpar. Os dados obtidos foram avaliados pelo MannWhitney test (5%). Resultados: Segundo Mann-Whitney test, o grupo ausência sofreu DT de 2 °C, enquanto o grupo presença variou 1 °C. Os valores de média da DT foram de 0.82±0.56 °C para o grupo presenca de PPS e 2.30 ± 0.73 °C para o grupo ausência de PPS. Conclusão: A pressão pulpar simulada reduziu significantemente a elevação de temperatura na câmara pulpar durante a fotopolimerização do sistema adesivo, demonstrando a importância de inserir esse protocolo de simulação de pressão pulpar nos procedimentos laboratoriais.(AU)

Micro-shear bond strength to dentin under simulated pulpal pressure / 대한치과보존학회지

The aim of this study was to measure and compare the micro shear bond strengths of the following dentin bonding systems to the dentin surfaces under simulated pulpal pressure; All Bond 2(R), Second(R), AdheSE(R), Adper Prompt L-Pop(R). The occlusal surfaces of 180 extracted human molars were prepared so the dentin bonding surfaces could be exposed. The teeth were randomly assigned to 3 equal groups of 60 each and subdivided. The dentin surfaces were treated with the above mentioned bonding system and resin composite cylinders were built up under a simulated pulpal pressure when saline (Group II) or diluted bovine serum (Group III) was used as the pulpal fluid. As a control, the same procedures were performed in the dried dentin surfaces (Group I). After one day of storage in water, the micro shear bond strengths were measured using an EZ tester. Group II and III showed significantly lower shear bond strength than Group I statistically (p < 0.05). SEbond(R) and AdheSE(R) showed no difference among the different dentin condition. In the Adper Prompt L-Pop(R), a simulated pulpal pressure were applied to the specimens using diluted bovine serum, which showed a higher strength than the specimens in which saline was used (p < 0.05).