Influence of the height of the mandibular ridge on the masticatory function during the functional adaptation with new complete dentures The period of functional adaptation to a new conventional complete denture embraces many transitory issues, and this period is directly related to the rehabilitation success. Objective: This clinical trial evaluated the influence of the height of mandibular ridge on the masticatory function of complete denture (CD) wearers during the adaptation period. Methodology: A total of 28 individuals wearing new CDs (NR, n=14, normal mandibular ridges, 64±12.5 years, 9 female; RR, n=14, resorbed mandibular ridges, 69±6.8 years, 9 female) were assessed at 24 hours, 30 days, three months and six months after the insertion of the CDs for masticatory performance (MP, sieves method), satisfaction with CDs (questionnaire) and maximum occlusal bite force (MOBF) (gnatodynamometer). The classification of the mandibular ridges followed the Kapur index. Data of MP and MOBF were analyzed by twoway ANOVA and satisfaction with CDs was analyzed by Generalized Estimating Equations (GEE), α=.05. Results: Participants with NR presented better masticatory performance (p=.000-NR 30.25±9.93%, RR 12.41±7.17%), general satisfaction (p=.047), retention of mandibular denture (p=.001), chewing ability (p=.037), and comfort of wearing a mandibular denture (p=.000). Regardless of the mandibular ridge, MP (p=.000) was higher at three (21.26±12.07%) and six months (24.25±12.26%) in comparison to 24 hours (18.09±10.89%), the MOBF (p=.000) was higher at three months (78.50±6.49 N) compared to 24 hours (57.34±5.55 N) and 30 days (62.72±5.97 N), and the comfort of wearing a mandibular denture (p=.002) at three months (1.61 ± 0.07) was greater than 24 hours (1.29±0.10) and 30 days (1.36±10). Conclusions: The study suggests that the participants with NR have higher MP and satisfaction with their CD, regardless of the follow-up period after the insertion of the new CD. After subjects received the CD, a period of 3 months was necessary for achieving better achievement MOBF, MP, and self-perceived comfort with the mandibular denture, regardless of the height of the mandibular ridge.

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PURPOSE The aim of this study was to evaluate the flexural strength of a 3D-printed denture base resin (Cosmos Denture), after different immediate repair techniques with surface treatments and thermocycling. MATERIALS AND METHODS Rectangular 3D-printed denture base resin (Cosmos Denture) specimens (N = 130) were thermocycled (5,000 cycles, 5℃ and 55℃) before and after the different repair techniques (n = 10 per group) using an autopolymerized acrylic resin (Jet, J) or a hard relining resin (Soft Confort, SC), and different surface treatments: Jet resin monomer for 180 s (MMA), blasting with aluminum oxide (JAT) or erbium: yttrium-aluminum-garnet laser (L). The control group were intact specimens. A three-point flexural strength test was performed, and data (MPa) were analyzed by ANOVA and Games-Howell post hoc test (α = 0.05). Each failure was observed and classified through stereomicroscope images and the surface treatments were viewed by scanning electron microscope (SEM). RESULTS Control group showed the highest mean of flexural strength, statistically different from the other groups ( P < .001), followed by MMA+J group. The groups with L treatment were statistically similar to the MMA groups ( P > .05). The JAT+J group was better than the SC and JAT+SC groups ( P < .05), but similar to the other groups ( P > .05). Adhesive failures were most observed in JAT groups, especially when repaired with SC. The SEM images showed surface changes for all treatments, except JAT alone. CONCLUSION Denture bases fabricated with 3D-printed resin should be preferably repaired with MMA+J. SC and JAT+SC showed the worst results. Blasting impaired the adhesion of the SC resin.