Journal of Dentistry, cilt.172, 2026 (SCI-Expanded, Scopus)
Objective: Debonding of denture teeth from denture base resins remains a common clinical complication, particularly with the increasing adoption of digital denture fabrication techniques. Although monolithic CAD/CAM dentures eliminate the tooth–base interface, many digital systems rely on bonding prefabricated or printed teeth to milled or printed denture bases, potentially compromising long-term interfacial durability. This in vitro study evaluated shear bond strength (SBS) and failure characteristics across conventional, additive, subtractive, and monolithic CAD/CAM techniques, and further assessed the influence of thermocycling. Methods: A total of 120 standardized specimens (n = 20 per technique) were fabricated, each consisting of a maxillary central incisor bonded to a cylindrical denture base. Six material groups were evaluated: conventional heat-polymerized PMMA (CONV), two additively manufactured groups (3DP-1, 3DP-2), a separately milled group (SM), and two monolithic milled groups (MM-1, MM-2). Specimens were further allocated into non-thermocycled and thermocycled subgroups (n = 10). Thermocycling was performed for 10,000 cycles between 5 °C and 55 °C. SBS was measured using a universal testing machine. Failure modes were evaluated using stereomicroscopy and scanning electron microscopy (SEM). Data were analyzed using two-way ANOVA followed by Tukey's HSD post-hoc tests (α = 0.05). Results: Fabrication technique and thermocycling significantly affected SBS (P < 0.001). Monolithic milled groups demonstrated the highest SBS and aging resistance, whereas the SM group showed the lowest values and greatest degradation. Conclusions: SBS between denture base and denture teeth is strongly influenced by fabrication technique. Monolithic CAD/CAM milling provides superior bond durability and resistance to thermal aging. Clinical significance: The results indicate that denture fabrication technique directly influences tooth–base bonding reliability. Monolithic design may reduce tooth debonding by eliminating the adhesive interface, whereas systems requiring bonding of prefabricated teeth, particularly separately milled designs, may be more prone to interfacial failure after thermal aging. When bonded designs are used, clinicians should consider material compatibility and surface treatments to improve long-term retention.