The effect of Er:YAG laser irradiation on the bond stability of self-etch adhesives at different dentin depths

Abstract

The aim of this study was to evaluate the effect of Er:YAG laser irradiation on the micro-shear bond strength of self-etch adhesives to the superficial dentin and the deep dentin before and after thermocycling. Superficial dentin and deep dentin surfaces were prepared by flattening of the occlusal surfaces of extracted human third molars. The deep or superficial dentin specimens were randomized into three groups according to the following surface treatments: group I (control group), group II (Er:YAG laser; 1.2 W), and group III (Er:YAG laser; 0.5 W). Clearfil SE Bond or Clearfil S3 Bond was applied to each group’s dentin surfaces. After construction of the composite blocks on the dentin surface, the micro-shear bond testing of each adhesive was performed at 24 h or after 15,000 thermal cycles. The data were analyzed using a univariate analysis of variance and Tukey’s test (p < 0.05). Laser irradiation in superficial dentin did not significantly affect bond strength after thermocycling (p > 0.05). However, deep-dentin specimens irradiated with laser showed significantly higher bond strengths than did control specimens after thermocycling (p < 0.05). Thermocycling led to significant deterioration in the bond strengths of all deep-dentin groups. The stable bond strength after thermocycling was measured for all of the superficial-dentin groups. No significant difference was found between the 0.5 and 1.2 W output power settings. In conclusion, the effect of laser irradiation on the bond strength of self-etch adhesives may be altered by the dentin depth. Regardless of the applied surface treatment, deep dentin showed significant bond degradation.

Influence of Dentine Pre-Treatment by Sandblasting with Aluminum Oxide in Adhesive Restorations. An In Vitro Study

“…The sum of these factors can reduce the survival rate of the bonded restorations [ 7 ]. However, adhesion is obtained through an exchange process in which minerals removed from the hard tissues are replaced by resin monomers, forming chemical bonds or micromechanical interlocking, called hybrid layer [ 8 , 9 ]. Comparing the bonding in enamel with that in dentin, we can note that it is particularly challenging due to the dentin composition, which has a lower inorganic component than enamel.…”

Comparison between Shear Bond Strength of Er:YAG and Er,Cr:YSGG Lasers-Assisted Dentinal Adhesion of Self-Adhering Resin Composite: An Ex Vivo Study

“…Thermocycling is widely used to simulate the oral conditions affecting the bonding of composite to enamel and dentin with time. Extreme temperatures are known to weaken the physicochemical properties of bonding [ 9 , 10 , 11 ]. There is an absence in published reports related to the effect of thermocycling on bonding SACs to laser-irradiated dentin.…”

Influência de diferentes protocolos de irradiação do laser de Er:YAG na morfologia dentinária, na formação da camada híbrida e na resistência adesiva

“…A interação física entre o laser e o tecido depende da natureza do tecido, da quantidade de água e dos diversos parâmetros de regulagem do equipamento empregado (Hibst;Keller, 1989). De acordo com os diferentes parâmetros, o laser pode remover tecido dental duro, realizando o preparo cavitário (Trevelin et al, 2015;Karadas et. al., 2017) e pode promover o pré-tratamento da dentina (Trevelin et al, 2015) prévio aos procedimentos restauradores adesivos.…”

“…Entretanto, analisando a literatura referente à adesão em dentina irradiada, resultados inconclusivos e controversos são encontrados (Ramos et al, 2010;Firat et al, 2012;Guven et al, 2015;Karadas et al, 2017). Da mesma maneira que estudos revelam a superioridade do laser frente ao tratamento convencional, por exibirem valores de resistência de união iguais (Celik et al, 2006;Staninec et al, 2006;Amaral et al, 2008;Akin et al, 2012) ou superiores (Visuri et al, 1996a;Chousterman et al, 2010;Ferreira et al, 2010;De Oliveira et al, 2013) aos métodos convencionais realizados com brocas e motores odontológicos, outros estudos revelam alterações termomecânicas geradas na superfície irradiada, resultando em alterações nas fibrilas colágenas da dentina, repercutindo em baixos valores de resistência de união (Ceballos et al, 2002;Sassi et al, 2004;Barceleiro et al, 2011;Ramos et al, 2013).…”

“…Contudo, a literatura que avalia a resistência de união de restaurações RU adesivas realizadas sobre substrato dental irradiado é controversa (Kameyama et al, 2009;Ramos et al, 2010;Akin et al, 2012;Guven et al, 2015). Se por um lado autores observaram valores de resistência de união mais altos (Visuri et al,1996a;Chousterman et al, 2010;Ferreira et al, 2010;Shahabi et al, 2013) ou iguais (Celik et al, 2006;Staninec et al, 2006;Amaral et al, 2008;Akin et al, 2012;Karadas et al, 2017) aos valores obtidos quando a adesão é realizada sobre dentina preparada pelos métodos convencionais, outros (Ceballos et al, 2002;Sassi et al, 2004;Barceleiro et al, 2005;Ramos et al, 2010;Bahrami et al, 2011) observam menores valores de resistência de união. A grande diversidade de protocolos de irradiação dificulta a escolha mais apropriada que possa conferir subsídio científico para sua utilização clínica.…”