Clinical effects of acrylic resilient denture liners applied to mandibular complete dentures on the alveolar ridge

The purpose of this study was to investigate whether resilient denture liners has the potential to decrease problems affecting the alveolar ridge mucosa during the first adjustment session following the initial fitting of the denture. Interventions were complete denture treatment with permanent acrylic resilient denture liner dentures (RLD) in mandibles and conventional heat-activated acrylic resin dentures (ARD) in mandibles. Maxillary dentures were fabricated with conventional heat-activated ARD. Seventy-four subjects were randomly allocated to the RLD and ARD groups by random permuted blocks within the strata method after obtaining written informed consent. A randomized controlled parallel clinical trial with two hospital centres was conducted from April 2004 to July 2006. The problems were comprehensively evaluated by three outcomes with subjective and objective factors as follows: (i) numbers of sore spots, (ii) duration of wearing dentures and (iii) pain perception with 100 mm Visual Analog Scale. The numbers of sore spots in the mandibular support and border areas for the RLD group were significantly less than those for the ARD groups (P < 0.05). The RLD wearers were able to wear their dentures an additional day longer than the ARD wearers (P < 0.05). The maxillary and mandibular pain ratings for the RLD group were significantly lower than those for the ARD group (P < 0.05). Application of resilient denture liners to mandibular complete dentures provided edentulous patients with fewer problems affecting the alveolar during the first adjustment session following the initial fitting of the denture when compared with conventional denture treatments.     

Reliability of a two‐colour chewing gum test to assess masticatory performance in complete denture wearers

The aim of this study was to test the reliability of a method to measure the masticatory performance of complete denture wearers employing a colour‐mixing ability test and assessment by visual and electronic colourimetric analysis. A sample of 75 subjects was selected from patients who received new conventional complete dentures. Masticatory tests were performed using a two‐colour chewing gum that was masticated for 5, 10, 20, 30 and 50 chewing cycles, performed in a random order. The mixing level of the two colours of the chewed gum was assessed visually by two independent raters based on a 5‐point ordinal scale. The specimens were flattened into a 1‐mm‐width wafer, scanned and saved as a two‐sided digital image. Each pair of images was submitted to an electronic colourimetric analysis to assess the level of colour mixture, measured by the circular variance of hue (VOH ). Overall inter‐ and intra‐rater agreements in visual analysis were 64% and 68%, respectively (almost 99% of scores ranged within ±1 point), whilst overall weighted kappa was >0.80. A proportional increase in the level of mixture occurred with increased number of chewing cycles (P  < .001). Similarly, VOH and the visual analysis were highly correlated (r = ?.89; P  < .001). Bland‐Altman plots revealed excellent agreement and extremely low systematic error between duplicated VOH measures. It was concluded that the two‐colour chewing gum test is a reliable method to assess the masticatory performance in complete denture wearers using both visual and electronic colourimetric analyses.     

Randomized controlled clinical trial for verifying the effect of silicone-based resilient denture liner on the masticatory function of complete denture wearers

PURPOSE: The purpose of this study was to investigate whether application of permanent silicone-based resilient denture liner (SR) to mandibular complete dentures significantly improves patients' masticatory ability compared to conventional heat-activated acrylic resin (AR). MATERIALS AND METHODS: Twenty-eight edentulous patients were randomly placed into 1 of 2 crossover groups (AR-SR/SR-AR) by using a random permuted block within strata method. The AR-SR group received AR denture treatments followed by SR denture treatments. The SR-AR group received treatments in the reverse sequence. The outcomes were classified by matiscatory performance, mandibular movement, electromyographic activity, and maximum occlusal force. RESULTS: No significant differences were observed in any of the baseline characteristic measurements between groups. SR denture wearers exhibited significantly higher masticatory performance than AR denture wearers. SR denture wearers exhibited a longer early-stage occluding period than AR denture wearers. There were no differences in electromyographic activity between the AR and SR groups. There were no significant differences in maximum occlusal force between the AR and SR groups. CONCLUSION: This study showed that the application of SR to mandibular complete dentures resulted in significant improvements to the patients' masticatory ability compared to AR.     

The influence of occlusion on masticatory performance and satisfaction in complete denture wearers

Complete dentures should satisfy patients' needs for comfort, function and aesthetics. Thirty edentulous patients were enrolled in this study. Two sets of complete dentures were made for each patient: one with bilaterally balanced occlusion and the other with lingualised occlusion. The patients used each type of denture for 6 months. A single‐blind study design was used in which the patients were not aware of the exchange of dentures. In each 3‐month period, electromyographic measurements of the anterior temporalis and masseter muscles were performed. At the end of 6 months, patient satisfaction was evaluated. The second measurement of lingualised occlusion showed the greatest muscle activity, while chewing gum in both the anterior temporalis and masseter muscles (174·5 and 208·19 μV, respectively). The greatest maximum voluntary contraction was also found for the second measurement of lingualised occlusion for both the anterior temporalis and masseter muscles (142·91 and 187·55 μV, respectively). The mean chewing time decreased with lingualised occlusion. The percent distribution of the patients' ratings of their complete dentures and patient satisfaction with lingualised occlusion were higher than those for bilaterally balanced occlusion. Complete dentures with lingualised occlusion increased masticatory performance, maximum voluntary contraction and patient satisfaction and decreased chewing time.     

Effect of dentist's clinical experience on treatment satisfaction of a complete denture

The relationship between the prosthodontic experience of dentists and satisfaction of complete denture wearers remains unknown. To investigate whether a prosthodontist's clinical experience affects treatment satisfaction of a complete denture wearer. From April 2004 to July 2006, we conducted a randomised controlled trial at two centres, including 74 edentulous patients; of these, 32 and 30 were randomly allocated to the ED or ID group, respectively. All the patients rated their satisfaction with dentures, including general satisfaction and satisfaction of chewing ability, speaking, cleaning, stability, retention, comfort and aesthetics. These satisfaction ratings were measured by a 100‐mm visual analog scale (VAS). Perceived chewing ability to foods, divided into five grades, was measured using a questionnaire. The mastication index (MI) was calculated for each grade. General satisfaction and satisfaction of speaking, stability and retention were significantly higher in the ED than in the ID group (P = 0·049, 0·003, 0·019 and 0·041, respectively). No significant difference existed between the MI of the ED (71·3 ± 18·4) and ID group (64·1 ± 16·53). However, the perceived chewing ability of grade 5 food, whose texture was the hardest among all the grades, was significantly higher in the ED group than in the ID group. Within its limitations, this study showed that a clinician's prosthodontic experience affects a complete denture wearer's satisfaction ratings.     

The influence of resilient liner and clip attachments for bar‐implant‐retained mandibular overdentures on opposing maxillary ridge. A 5‐year randomised clinical trial

This study aimed to compare the influence of resilient liner and clip attachments for bar‐implant‐retained mandibular overdentures on opposing maxillary ridge after 5 years of denture wearing. Thirty edentulous male patients (mean age 62·5 years) received two implants in the anterior mandible after being allocated into two equal groups using balanced randomisation. After 3 months, implants were connected with resilient bars. New maxillary complete dentures were then constructed, and mandibular overdentures were retained to the bars with either clips (group I, GI) or silicone resilient liners (group II, GII). The prosthetic and soft tissue complications of the maxillary dentures were recorded 6 months (T_6 m), 1 year (T1), 3 years (T3) and 5 years (T5) after overdenture insertion. Traced rotational tomograms were used for measurements of maxillary alveolar bone loss. The proportional value between bone areas and areas of reference not subject to resorption was expressed as a ratio (R). Change in R immediately before (T0) and after 5 years (T5) of overdenture insertion was calculated. Maxillary denture relining times and frequency of flabby anterior maxillary ridge occurred significantly more often in GI compared with GII. The change of R in anterior part of maxilla was significantly higher than change of R in posterior part in both groups. GI showed significant resorption of anterior residual ridge compared with GII. Relining times and frequencies of flabby ridge were significantly correlated with change in R. Within the limitations of this study, resilient liner attachments for bar‐implant‐retained mandibular overdentures are associated with decreased resorption and flabbiness of maxillary anterior residual ridge and fewer maxillary denture relining times when compared with clip attachments.     

Comparison of two different surgical approaches to increase peri‐implant mucosal thickness: A randomized controlled clinical trial

1 Background

Current evidence supports the positive effect of adequate peri‐implant mucosal thickness (PMT) on both marginal bone level stability and esthetic outcomes. While the subepithelial connective tissue graft (sCTG) has been traditionally considered as the gold standard for peri‐implant mucosal augmentation, acellular dermal matrix (ADM) may be a valid alternative. The primary aim of this randomized clinical trial was to determine the clinical efficacy of ADM in the augmentation of PMT as compared to an autologous sCTG.

2 Methods

Patients who could benefit from peri‐implant mucosal augmentation at the time of implant placement were recruited. Participants were randomized to the control (simultaneous sCTG) or test (simultaneous ADM) group. The primary outcome in this study was changes in PMT between baseline and 16 weeks later. Keratinized mucosal width (KMW) changes, modified wound healing index (MWHI) variations and patient‐reported outcome measures (PROMs) were recorded, as well.

3 Results

A total of 20 participants were recruited per an a priori power analysis. There were no statistically significant differences between groups at baseline for any of the parameters analyzed. The gain in PMT at 1 mm, 3 mm, and 5 mm from the expected mucosal margin was 0.44 ± 2.04 mm, 1.20 ± 1.48 mm, and 1.20 ± 0.89 mm in the sCTG group, and 0.05 ± 1.57 mm, 0.85 ± 1.29 mm, and 1.45 ± 1.17 mm in the ADM group. No statistically significant differences in terms of PMT, KMW, and MWHI changes were observed between groups. The perceived discomfort was higher at 2 and 4 weeks for patients in the sCTG group.

4 Conclusion

ADM produces similar outcomes to sCTG in terms of mucosal augmentation at the time of implant placement.