Method: Ten subjects (2 male and 8 female; mean age 60.1 ± 6.6 years old) received conventional total maxillary dentures and free-end RPD in the mandible. Two months after denture insertion, swallowing threshold and nutrient intake assessments occurred, which included an evaluation of the number of masticatory cycles and medium particle size (X50) of a silicone test material (Optocal). A 3-day food diary verified nutrient intake based on a standard Brazilian Food Composition Table. Then, osseointegrated implants were placed bilaterally in the mandibular first molar region, followed by BA, which was fitted in the RPD bases after healing. After two months of the RPD over implants and BA use, variables were again assessed. Sample size leads to a minimum power of 0.8 % for minimum significant differences of 0.97 and 0.86 for the median particle size (swallow threshold parameter) and caloric intake, respectively. Paired t-tests and Wilcoxon rank-tests evaluated the data (P < 0.05).
Result: Masticatory cycles did not differ (P > 0.05) between treatments; however, subjects showed decreased X50 values at the swallowing moment (P = 0.003), and increased daily energy (P = 0.008), carbohydrate (P = 0.003), protein (P = 0.030), calcium (P = 0.006), fiber (P = 0.040), and iron (P = 0.038) intake when they were using their RPD over posterior implants retainers and BA inserts. No differences were found in fat consumption (P > 0.05).
Conclusion: Posterior implants and BA retainers over a free-end RPD resulted in smaller swallowed median particle size and improved nutrient intake.