Assessment of masticatory function and nutrition in people with dental implants

Abstract: Background: Treatment with bimaxillary implant-supported fixed prostheses is the state-of-the-art treatment of complete edentulism and replacement of natural teeth. However, the extraction of teeth results in the loss of periodontal mechanoreceptors (PMRs), normally located in the periodontal ligament. Complete edentulism implies a total absence of PMRs. The total lack of input from PMRs, which is involved in encoding relevant aspects such as the magnitude of biting forces, makes this group unique. The complete retaining of the prostheses and optimised restored function, anatomy, and aesthetics, mostly to the great satisfaction of the patient, make the group even more unique and interesting. However, the literature lacks studies assessing masticatory function and nutrition in completely edentulous people treated with bimaxillary implant-supported fixed prostheses. In fact, compared to other prosthetic treatments, such as hip and knee joint replacements, assessment routines for the outcomes of implant treatments are rare. The subjective and objective evaluations of masticatory function and assessment of nutritional status, nutritional risk and eating habits could be key factors for optimising masticatory function in people treated with implants. Objectives: The thesis aims to assess the masticatory function and nutrition in people treated with bimaxillary implant-supported fixed prostheses compared to people with natural dentitions. Identifying differences and similarities between the groups may clarify functional impairments, nutritional deficiencies, and risks. Material and methods: The thesis focuses on assessing various aspects of masticatory function and nutrition in people treated with bimaxillary implant-supported fixed prostheses compared to a control group of people with natural dentitions. Study I focuses on the establishment of a protocol/methodology for assessment of masticatory performance using a hard viscoelastic test food. Study II focuses on that agreement between the established objective measure of masticatory performance with a subjective evaluation of functional limitations and quality of life. Study III evaluates nutritional measures in people with bimaxillary implant-supported fixed prostheses. Nutritional status, nutritional risk and eating habits are assessed in comparison to an equivalent control group of people with natural dentition. Results: The overall results of the three studies reveal significant differences between the groups. The masticatory performance is significantly lower in people treated with bimaxillary implant-supported fixed prostheses (Studies I & II). However, there is no correlation between the objective indicators of masticatory performance and the subjective measures of any major limitation in function or quality of life (Study II). The differences are, however, present when analysing nutritional status, nutritional risk and eating habits (Study III). The participants in the implant group exhibited a significantly lesser variety of consumed food and a higher risk of malnutrition. Body Mass Index (BMI) was significantly higher and in the overweight range compared to normal weight in the control group. The risk of nutritional deficiency was significantly higher among participants with bimaxillary implant-supported fixed prostheses and in the range of high compared to moderate in the control group. Conclusion: The success of treatment with bimaxillary implant-supported fixed prostheses, considered state-of-the-art treatment, is reflected in subjective measures of patient- reported satisfaction and high oral health-related quality of life. However, the masticatory performance is significantly impaired. Eating habits and nutritional status can be negatively affected, resulting in an increased risk of nutritional deficiencies and malnutrition.