Assessment of masticatory function in older individuals with bimaxillary implant-supported fixed prostheses or with a natural dentition: A case-control study.

STATEMENT OF PROBLEM: A clinical assessment of the masticatory performance of edentulous people treated with bimaxillary implant-supported fixed prostheses is lacking. PURPOSE: The purpose of this case-control study was to compare the masticatory performance of edentulous people treated with bimaxillary implant-supported fixed prostheses to that of those with a natural dentition by using a simplified comminution test with hard viscoelastic test food and a mixing ability test. MATERIAL AND METHODS: Thirty-six participants were recruited and divided into 2 equal groups (n=18) based on their dental status. The experimental group (7 women, mean ±standard deviation age=69.8 ±7.5 years) had bimaxillary implant-supported fixed prostheses, and the control group (9 women, mean ±standard deviation age=68.3 ±5.6 years) had a natural dentition. A hard viscoelastic food comminution test and a mixing ability test with 2-colored chewing gum were performed in both groups. The number and total area of the particles during the comminution test and the variance of hue during the mixing ability test were measured. The data were analyzed with the parametric (paired t test) and nonparametric (Mann-Whitney U) tests to assess differences between the groups (α=.05). RESULTS: The experimental group exhibited significantly fewer pieces in the food comminution test than the control group (P=.001). The experimental group also showed significantly higher variance of hue values than the control group (P<.001). CONCLUSIONS: Patients treated with bimaxillary implant-supported prostheses had reduced masticatory performance in comparison to those with a natural dentition, despite having been provided with satisfactory and well-functioning prostheses.

Subjective and objective evaluation of masticatory function in patients with bimaxillary implant-supported prostheses.

BACKGROUND: People perform poorly in masticatory function tests despite well-functioning prostheses. However, it is unclear whether there is an agreement between subjective and objective measures of mastication. OBJECTIVES: To investigate the association between subjective and objective measures of masticatory function in patients with bimaxillary implant-supported prostheses. MATERIALS AND METHODS: An experimental group (n = 25, age = 70.6 ± 7.5 years, eight women) with bimaxillary implant-supported fixed prostheses and a control group (n = 25, age = 69.0 ± 5.3, 13 women) with natural dentition were recruited. The participants in the experimental group were included if they had been using the prosthesis for at least a year and had no obvious complaints with their prostheses. The control group was people with natural dentition and without any prostheses or complaints related to the masticatory system. The masticatory function was evaluated objectively with food comminution and mixing ability tests, and subjectively with jaw function limitation scale (JLFS) and oral health impact profile (OHIP). RESULTS: The experimental group performed poorly in both objective tests (p < .001). However, there was no significant differences between the two groups in total JFLS (p = .114) and OHIP (p = .312) scores. Though, there were certain positive correlations between the food comminution test and JFLS subdomains in the control group, and a positive correlation between food comminution test and specific subdomains of OHIP in the experimental group indicating poor correlation between the subjective and objective measures. CONCLUSION: Although patients with implant prostheses show poor masticatory performance, there is no agreement in the objective and subjective measures of mastication.

Five-year evaluation of Lifecore Restore implants: a retrospective comparison with Nobel Biocare MK II implants.

PURPOSE: The purpose of this study was to compare survival rates and marginal bone resorption of the Lifecore (LC) Restore Implant System with the benchmark Nobel Biocare (NB) MK II Implant System. MATERIALS AND METHODS: All implants were inserted by the same surgeon and all radiological analyses were performed by the same radiologist. Two hundred ninety LC implants were analyzed radiologically after 1 year and compared with the same number of NB implants serving as a historical reference group. After 5 years, 200 LC implants could be compared with 224 NB implants. Each implant was monitored for exposed threads, as compared with the baseline registrations. RESULTS: No significant differences were found between the two implant systems regarding survival rates (LC 100% and NB 99.2%). Considering the findings of this study, the two implant systems compared might be regarded as clones. Nevertheless, because of dissimilar onset of threads, about 1 mm more implant-retaining bone anchorage is gained with the Lifecore Restore Implants as compared with NB MK II Implants. CONCLUSIONS: Based on the assumption that >3 exposed NB threads correspond to >4 exposed LC threads, significantly more bone loss (p < .01) could be demonstrated for the NB implants after 5 years. Thus, it may be justified to consider the differences in implant design to have a decisive clinical relevance.