IADR Abstract Archives
FESEM Analysis of Milled Lithium Disilicate Treated With HF or Self-Etching-Ceramic-Primer
Objectives: To compare the ultra-morphology of lithium disilicate (LD) milled with standard-bur and treated with hydrofluoric acid (HF) or with a self-etching ceramic primer (MEP).
Methods: Sixteen LD (IPS e.max CAD, Ivoclar Vivadent) sections (4x4x1mm3) were wet milled in a Cerec 3 Milling Unit (Dentsply Sirona) using a sequence of milling diamond bur (Step Bur 12S, Step Bur 12, and Cylinder Pointed Bur 12ExtraFine, Dentsply Sirona) with controlled rotation (40.000rpm) and milling speed (0.4-0.6mm/min). After milling, LD specimens were fired following the crystallization program and assigned to 4 groups (n=4): G1=5%HF (IPS Ceramic Etching Gel, Ivoclar Vivadent) applied for 20s; G2=10%HF (Condac Porcelana, FGM) applied for 20s; G3= MEP (Monobond Etch&Prime, Ivoclar Vivadent) applied with a microbrush and rubbed for 20s. The MEP solution was left on the surface for 40s, rinsed and dried following manufacturer’s instructions; and G4=Untreated LD (control). Specimens were cleaned ultrasonically with distilled water for 180s, air-dried, sputter-coated with gold-palladium, and observed under a FESEM (JSM-6701F, JEOL) at magnifications 5,000X-40,000X.
Results: No retentive pattern was observed for control specimens; grooves were produced on LD surface; between the grooves, LD presented a smooth surface. LD treated with 5%HF and 10%HF resulted in apparent similar etching pattern with an array of exposed crystals without over-etched areas; LD specimens displayed the most pronounced etching pattern in the groove areas but there were no detectable unsupported LD crystals. MEP resulted in LD surface similar to those in control group. Groove areas produced on LD surface and treated with MEP exhibited a slight increase in retention pattern compared to control.
Conclusions: LD surface treated with both HFs included in the present project resulted in a retentive ceramic pattern without areas of over-etching. All ceramic etchants etched glass-matrix ceramic deeper in the groove areas formed during ceramic milling process; apparently, MEP resulted in slight increase in micromechanical retention only in these areas.
Methods: Sixteen LD (IPS e.max CAD, Ivoclar Vivadent) sections (4x4x1mm3) were wet milled in a Cerec 3 Milling Unit (Dentsply Sirona) using a sequence of milling diamond bur (Step Bur 12S, Step Bur 12, and Cylinder Pointed Bur 12ExtraFine, Dentsply Sirona) with controlled rotation (40.000rpm) and milling speed (0.4-0.6mm/min). After milling, LD specimens were fired following the crystallization program and assigned to 4 groups (n=4): G1=5%HF (IPS Ceramic Etching Gel, Ivoclar Vivadent) applied for 20s; G2=10%HF (Condac Porcelana, FGM) applied for 20s; G3= MEP (Monobond Etch&Prime, Ivoclar Vivadent) applied with a microbrush and rubbed for 20s. The MEP solution was left on the surface for 40s, rinsed and dried following manufacturer’s instructions; and G4=Untreated LD (control). Specimens were cleaned ultrasonically with distilled water for 180s, air-dried, sputter-coated with gold-palladium, and observed under a FESEM (JSM-6701F, JEOL) at magnifications 5,000X-40,000X.
Results: No retentive pattern was observed for control specimens; grooves were produced on LD surface; between the grooves, LD presented a smooth surface. LD treated with 5%HF and 10%HF resulted in apparent similar etching pattern with an array of exposed crystals without over-etched areas; LD specimens displayed the most pronounced etching pattern in the groove areas but there were no detectable unsupported LD crystals. MEP resulted in LD surface similar to those in control group. Groove areas produced on LD surface and treated with MEP exhibited a slight increase in retention pattern compared to control.
Conclusions: LD surface treated with both HFs included in the present project resulted in a retentive ceramic pattern without areas of over-etching. All ceramic etchants etched glass-matrix ceramic deeper in the groove areas formed during ceramic milling process; apparently, MEP resulted in slight increase in micromechanical retention only in these areas.