الفهرس | Only 14 pages are availabe for public view |
Abstract Aim: This study was carried out to investigate the effect of Er:Yag laser ablation on the bonding efficacy and durability of ceramic blocks to enamel and dentin using contemporary resin cements. Materials and methods: Half of exposed flattened labial and occlusal surface of 60 upper central teeth and 60 molar teeth respectively were marked with a permanent felt-tip marker. Subsequently, these marks were erased using high speed cylindrical carbide bur # (C21.314.008) (EDENTA AG, Switzerland) in bur-prepared groups (B). The other half was marked and the marks were erased using an Er:YAG laser (Fidelis, Fotona ) in laser-ablated groups (L). The prepared teeth were divided into three groups of 20 teeth each according to the type of resin cement used to lute 3mm thick ceramic sections; either conventional resin cement with pretreatment with either etch-and-rinse (E&R) or self-etch (SE) adhesive or the direct use of selfadhesive cement (SA). After cementation, the teeth were stored in artificial saliva then half of the specimens from each subgroup (10 teeth) were tested after 24 hours (I). The other half was aged by storage for six month (A). 7 teeth from each subgroup were randomly selected for the microtensile bond strength (μTBS) test. Meanwhile, the remaining 3 teeth were allocated for the ultramorphological analysis. Results: In the enamel group, laser ablation didn’t influence the bonding performance of (E&R) and (SE) at both 24 hours and 6 months storage in artificial saliva. Moreover, when (SA) was used, there was no statistically significant difference between (μTBS) of B and L initially. Meanwhile, laser ablation improved the bonding ability of (SA) after aging. Furthermore, with the three tested resin cements, the results indicate no degradation of (μTBS) after aging with B and L. Moreover, (E&R) exhibited the highest bond strength to B and L. For the dentin group, there was no statistical significant difference between (μTBS) of B and L groups with both (E&R) and (SE) systems after 24 hours storage. Meanwhile, after aging, (μTBS) of B (E&R) and B (SE) groups significantly decreased. On the contrary, L groups restored with (E&R) and (SE) were not affected by aging and their (μTBS) remained stable after 6 aging. (SA) cement showed significant higher (μTBS) to L when tested after 24 hours. On the other hand, its bond strength to B significantly increased after aging, to become statistically similar to L, while the bond strength of the same cement to L remained stable after aging. Clinical Significance: Utilizing Er:Yag laser for tooth preparation is a viable alternative that enhances durable bonding of indirect machinable ceramic restorations. |