Comparing Masticatory Performance of Maxillary Mini Dental Implant Overdentures, Complete Removable Dentures and Dentate Subjects

Changes in masticatory performance and bite force after treatment with mandibular overdentures retained by four titanium-zirconium mini implants: One-year randomised clinical trial

OBJECTIVE

This prospective study is part of a randomised clinical trial and reports the changes in masticatory performance (MP) and bite force, and explores their influential factors, 1 year after the provision of mandibular overdentures retained by four titanium-zirconium mini implants.

METHODS

Edentulous patients received conventional complete dentures, followed by placement of four mini implants (Straumann® Mini Implant System) in the anterior mandible and converting the conventional prosthesis into a mandibular overdenture. Treatment protocols were randomised using a 2×2 factorial design combining different surgical (flapped vs. flapless) and loading (immediate vs. delayed) protocols. MP was assessed using a two-colour mixing ability test and a colorimetric analysis to measure the level of colour mixing (Variance of Hue-VoH). Maximum voluntary bite force (MBF) was measured by a digital gnathodynamometer in the posterior and anterior regions. Sex, age, surgical and loading protocols and ridge morphology were tested as independent variables. MP and MBF tests were performed at baseline (pre-treatment) and the 3-, 6- and 12-month after implant loading. Descriptive statistics, independent t-test, and linear mixed-effect model (LMM) regression were used for data analysis.

RESULTS

Seventy-four participants were assessed and 73 completed the 1-year follow-up. Statistically significant improvements in functional parameters were observed in all follow-up periods compared to baseline (p < .001). The flapless protocol was associated with higher improvement in MP at the 3-month follow-up (p = .004), while less resorbed ridges were associated with better MP (p = .038) and higher MBF (p < .001).

CONCLUSION

The mandibular overdenture protocol using four titanium-zirconium mini implants was effective in improving MP and MBF of edentulous patients, compared to pre-treatment values. The findings also suggest that improvements in chewing function and bite force are impacted by clinical factors since better outcomes were observed for flapless surgeries and less resorbed edentulous ridges.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.Gov ID NCT04760457.

Food Bolus Properties in Relation to Dentate and Prosthetic Status

The objective of this study is to evaluate food bolus properties (mass, moisture content and food comminution) in patients wearing fixed or removable dental prostheses. Methods: A cross-sectional study was conducted on a convenience sample of patients aged at least 55 years old. Patients chewed a 10 g sample of fresh raw carrot until they felt ready to swallow. The mass of the food bolus was determined as collected and after drying. Food comminution was assessed by the multiple sieve method. Results: Patients with fixed prostheses compared to those with removable prostheses registered a similar mass of food bolus as collected (4.40 g vs. 4.60 g; p = 0.856); a higher mass of dried food bolus (3.46 g vs. 0.86 g; p < 0.001); lower moister of food bolus (24.65% vs. 82.35%; p < 0.001); and better food comminution (mass of smaller particles, of size below 2 mm, represented 65.93% vs. 20% of dried food bolus). In removable denture wearers, food comminution was slightly better in partially than in completely edentulous patients, and rather similar in completely edentulous patients with either implant overdenture or complete denture in the mandible, and complete denture in the maxilla. Conclusions: The current results suggest that food bolus properties are dependent on the dentate and prosthetic status.