Background: Tooth development or odontogenesis is a complicated, multi-staged process, regulated by a plethora of genes. Disruptions during the early stages of odontogenesis may cause the complete absence of one or more teeth, known as tooth agenesis (TA). Except for PAX9, alterations in MSX1, AXIN2, WNT10A, and EDA/EDAR/EDARADD have gathered an increasing amount of interest. Objectives: This systematic review aims to investigate whether non-syndromic tooth agenesis (NSTA) is associated with MSX1, AXIN2, WNT10A, and EDA/EDAR/EDARADD mutations and to list the related phenotypic patterns of these alterations with regard to missing teeth. Methods: MEDLINE, Scopus, and Web of Science were the three selected databases. Duplicates were removed using Mendeley, and the records were assessed via the Rayyan platform. The Newcastle–Ottawa Scale was used to evaluate the quality of the evidence. Results: Fifteen case–control studies were eligible for this systematic review. The MSX1 gene was examined in most studies, whereas second premolars and lateral incisors were the most commonly missing teeth among TA cases. In total, 61.29% to 84.9% of the cases included one or two absent teeth. Conclusions: Due to the considerable heterogeneity in reporting results across the included studies, along with the high risk of bias present in most of them, it was not feasible to conduct a meta-analysis of the data. Nonetheless, the findings suggest that the NSTA phenotypes linked to the studied genes are similar to those associated with other forms of TA and share a common pattern of missing teeth. Future research should adopt a more standardized approach in presenting findings by adhering to established terminology and definitions and by utilizing common cut-off points to categorize results.

Background/Objectives: Wettability is a key surface property of denture base resins and is related to denture retention through interfacial cohesive–adhesive forces; conversely, compromised material wettability facilitates bacterial adhesion and colonization. Although three-dimensional (3D) printing has become an increasingly popular method for fabricating dentures, there is insufficient evidence regarding the wettability of 3D-printed denture base resins. This study aims to evaluate the wettability of 3D-printed, heat-polymerized, and milled denture base resins by comparing their contact angles. Methods: A search was conducted in MEDLINE, Scopus, and Web of Science, while grey literature was also assessed. The risk of bias was evaluated using the Quality Assessment Tool for In Vitro Studies (QUIN). Meta-analyses were conducted using inverse variance and the random effects model. Results: A total of nine and seven studies were included in the quantitative synthesis comparing 3D-printed denture base resins with heat-polymerized and milled resins, respectively. A statistically significant difference of −6.50 degrees was observed in favor of 3D-printed denture base resins compared to heat-polymerized ones (95% CI: −12.11 to −0.90, I² = 99%), while the comparison between 3D-printed and milled resins showed a non-statistically significant mean difference (MD: 0.87, 95% CI: −5.08 to 6.82, I² = 98%). Conclusions: The available in vitro evidence indicates that 3D-printed denture base resins tend to exhibit improved surface wettability compared with heat-polymerized resins and perform similarly to milled resins. However, given the extremely high heterogeneity, these findings should be interpreted with caution, as clinical performance depends on the complex interplay between surface characteristics and microbial adhesion rather than solely on wettability.

3D-printed denture base resins offer significant workflow advantages in denture fabrication, but may exhibit limitations in mechanical performance and surface quality. This in vitro study evaluated the effects of different surface-coating materials on the flexural properties and surface integrity of a 3D-printed denture base resin. Stereolithography-fabricated specimens were airborne-particle abraded and coated with single or double layers of four commercial glaze materials and an unpolymerized denture base resin; untreated specimens served as controls. Flexural properties were assessed utilizing an ISO 20795-1-based design, and surface morphology was evaluated using scanning electron microscopy (SEM) after 90 days of water immersion. Coating application (single versus double layers) did not significantly influence flexural strength or modulus. The control group exhibited the highest mean flexural strength. The unpolymerized resin groups performed closely to the ISO benchmark, whereas commercial coatings failed to enhance mechanical properties, occasionally reducing them below this reference value. Morphological analysis revealed surface irregularities in coatings lacking nanoparticles, whereas nanoparticle-containing coatings showed no visible surface defects after water storage. In conclusion, commercial glazes should be used with caution on 3D-printed resins due to potential mechanical compromise. The application of nanoparticle-containing coatings resulted in a stable surface topography, and unpolymerized resin coatings emerged as a feasible alternative.