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Er:YAG Surface Modification Mode Influences Surface Topography of Ablated Substrates

, Hatem El-Damanhoury, Dina Wafik Elkassas, Mai.M. Yousry
Published in

Objectives: To investigate the effect of adding laser surface modification parameters on the surface topography of ablated substrates, after phosphoric acid or self-etching adhesive. Bur cutting was used as control.

Methods: Flat enamel (E) and dentin (D) surfaces were either laser ablated with Er:YAG (L1E-250mJ, 30Hz) ( L1D-200mJ, 20Hz) only, with further surface modification parameters (SMP) (L2E and L2D-80mJ, 10Hz); or cut with carbide bur (CE and CD ). Each group was either left with no further treatment (L1En, L1Dn, L2En, L2Dn, CEn and CDn), etched with 37% phosphoric acid (Scotchbond, 3M) for 15 sec and washed (L1Ea, L1Da, L2Ea, L2Da, CEa, and CDa) or conditioned with self-etch adhesive (Adper Easy One, 3M) for 15 sec then ultrasonically cleaned in acetone bath (L1Es, L1Ds, L2Es, L2Ds, CEs and CDs) (n=3). Specimens were examined under scanning electron microscope (SEM).

Results: SEM revealed absence of smear layer in laser groups with micro-cracks, vitrification and re-crystallization in Enamel. L1En and L1Dn characterized by irregular surfaces with ill-defined etching patterns. SMP resulted in flatter surfaces with more ablation of enamel prisms in L2En and inter-tubular dentin in L2Dn. Acid etching led to deeper demineralization with type I core etching in L1Ea, absence of peritubular dentin and funneling of Tubules’ lumens in L1Da. L2Ea showed mixed etching patterns, while preservation of peritubular dentin and more constricted lumens was observed in L2Da. Self-etched groups revealed shallower demineralization; L2Es & L2Ds displayed ill-defined etching patterns. Smear layer and plugs were seen covering CEs & CDs.

Conclusions: Surface topography of the investigated groups varied widely with different combinations of ablation parameters and etching techniques, resulting in different characteristic patterns which could reflect on bonding effectiveness of restorations.

About the journal
JournalIADR/AADR/CADR General Session and Exhibition 2013
Open AccessNo