Effect of surface priming on the wettability of heat-polymerized polymethylmethacrylate, milled and 3D printed...

Computer-aided design and computer-aided manufacturing (CAD-CAM) complete dentures are commonly used with adhesives, relines, and repair materials to enhance comfort and function. However, to work satisfactorily, the reline material and the surface of the denture base must be compatible, or the latter should be treated to alter its surface properties to ensure a strong union. Research on the effect of surface priming on the wettability of heat-polymerized, milled, and 3D printed denture base polymers is limited. This systematic review aimed to analyse, summarise, and evaluate the available evidence on the integration of nanomaterials into COAs, with a focus on progress achieved, limitations regarding antibacterial effectiveness, and potential future directions in orthodontic therapy.

A total of 30 specimens were fabricated with 3 denture base polymers (Lucitone 199, IvoBase CAD, and NextDent Denture 3D+); 10 specimens for each group. One side of the specimens was primed with a light-polymerized methacrylate primer (VisioLink; Bredent), while the other side was left untreated. Subsequently, sterile water and 1-bromonaphthalene (1BrN) were used to evaluate the surface contact angle with an optical goniometer. The resulting data were analyzed using repeated measures 3-way ANOVA and post-hoc Step-down Bonferroni-corrected pairwise comparisons.

The statistical analysis suggrsted a 3-way interaction between the effect of the primer, the denture base material, and the testing liquid on the wettability of the different groups (P < 0.001). The primed heat-polymerized PMMA (73.6 ± 0.9°), 3D printed PMMA (76 ± 0.7°), and milled PMMA denture bases (64.6 ± 0.5°) exhibited high contact angles with distilled water, suggesting poor wettability to this liquid. Without priming, the distilled water contact angle was lower for the 3D printed photopolymer (53.6 ± 0.9°), milled PMMA (48.2 ± 0.8°), and heat-polymerized PMMA (43.2 ± 0.8°) denture base groups. For 1BrN, the contact angles were considerably lower across all groups. Non-primed surfaces exhibited contact angle values ranging from 16 ± 0.7° for heat-polymerized PMMA,14± 1° for milled PMMA, and 12 ± 1° for the 3D printed photopolymer specimens. Surface priming reduced these values to 11.2 ± 0.8°, 7.8 ± 0.8°, and 10.8 ± 0.8 °, respectively. The post-hoc analysis revealed statistically significant differences between materials without surface priming (P < 0.05). Similarly, significant differences were noticed when the same materials were evaluated before and after surface treatment (P < 0.05). When different denture base materials treated with the same surface treatment were evaluated, significant differences were detected between the primed 3D printed photopolymer and heat-polymerized PMMA, and between both PMMA groups treated with 1BrN (P < 0.05). Similar results were observed when distilled water was used as testing liquid (P < 0.05).

The light-polymerized methacrylate primer affected the wettability of the denture base polymers evaluated. The primer increased hydrophobicity toward polar liquids (distilled water), while improving wettability for the non-polar testing liquid (1-bromonaphthalene). Primer applications can enhance wettability to non-polar liquids, which can be beneficial when restorative materials with non-polar properties are to be used.