Primary Dentin Conditioning with Methylene Blue Activated Photodynamic Therapy, Phytic Acid, and Er,Cr:YSGG to Resin-Modified Glass Ionomer Cement in Comparison to Conventional Polyacrylic Acid.

Aim: Impact of surface conditioner phytic acid (IP6) Er,Cr:YSGG laser (ECYL) methylene blue photodynamic therapy (MB-PDT) on the microleakage and shear bond strength (SBS) of resin-modified glass ionomer cement (RMGIC) to primary sound dentin. Material and method: Overall, 80 extracted sound primary molars were collected followed by their submergence in self-cure acrylic resin. The dentin surface was exposed and made flat and was assigned into four groups based on the surface conditioning. Group 1: polyacrylic acid (PAA), Group 2: 1% IP6, Group 3: ECYL, and Group 4: MB-PDT. RMGIC restorative material was bonded to primary dentin. Marginal leakage assessment was performed using silver nitrate. SBS and failure mode assessment were performed using a universal testing machine and stereomicroscope. Mean and standard deviations of SBS and marginal leakage were compared using analysis of variance and multiple comparisons of Tukey's post-hoc test (p < 0.05). Results: MB-PDT treated specimens displayed the highest values of marginal leakage (37.56 ± 1.25 nm) and lowest SBS (7.93 ± 1.03 MPa). However, samples in Group 2 conditioned with IP6 presented the lowest dye penetration score (11.23 ± 1.22 nm) and highest bond strength scores (11.12 ± 0.82 MPa). Conclusions: IP6 and ECYL have proved to be better alternatives in terms of low microleakage and improved SBS scores to PAA as a primary dentin surface conditioner for bonding RMGIC restoration. Conversely, MB-PDT, when employed as a dentin surface conditioner for RMGIC restorations, exhibited suboptimal results, characterized by elevated microleakage and compromised bond strength.