Effect of Implant Treatment and/or Dietary Advice on the Nutrition of Edentulous Ageing Subjects

Loss of masticatory function consequent to tooth loss is associated with changes in food choices and insufficient nutrition intake. To date, studies showed no significant improvement in nutrient intake with interventions based solely on dental prostheses. Pilot studies have shown positive impacts of interventions combining implant-supported fixed dental prosthesis with brief dietary interventions. The relative contribution and the potential synergy of the components of such interventions need to be determined as it has major public health implications for the community-dwelling ageing population that continues to disproportionately suffer from tooth loss and its consequences.

This study tests the effect of rehabilitation of masticatory function with fixed implant supported dentures and diet re-education on the dietary intake and nutrition in older subjects with terminal dentition (stage IV periodontitis) or full edentulism.

A 2 × 2 factorial randomized controlled trial of eligible adult (≥60 years) with loss of masticatory function consequent to full arch edentulism or terminal dentition (n = 120) will be conducted to test whether the rehabilitation of masticatory function with fixed implant supported dentures, diet re-education and/or their combination improves the diet and nutrition of ageing subjects. The study has been designed to detect changes in fruit and vegetable intake at 4 months using the 24-hour dietary recall method. Changes in protein as percentage of total energy, nutritional biomarkers, metabolomics, oral and gut microbiome, quality of life and masticatory function will also be assessed.

Complete edentulism or presence of a terminal dentition that is functionally compromised in an irreparable way represent the end of the spectrum of caries and periodontitis, eventually leading to loss of masticatory function. These subjects tend to show change in their diet behavior choosing softer diets with higher carbohydrates and fat and less fresh fruit and vegetables.

Accumulating evidence points to the presence of an association between changes in dietary behavior consequent to tooth loss and insufficient nutrition intake. Such impaired nutrition may have long term effects on muscle strength and physical decline, and be detrimental to general health. Indeed, the recent GBD study of dietary risk factors identifies 15 important disease associated exposures. Their analysis shows that 5 of the health associated exposures: consumption of fruit, vegetables, whole grains, nuts, and fiber require a good level of mastication.

While the physiology of mastication is an essential component of alimentation and contributes to the broader process of nutrition, a more holistic approach is needed to properly establish the scientific basis of the contribution of oral health to nutrition and healthy ageing. Assuming a potential cause-effect relationship between the inadequate food choice consequent to tooth loss and compromised nutrition intake, several studies have tried to improve the nutrient intake among edentulous individuals with various types of dentures. However, this goal has not been readily achieved with either complete denture or implant-retained overdenture, given the function limitation on these prosthesis and the lack of dietary intervention.

A small-scale case series has shown that implant-supported fixed prosthesis resulted in more efficient mastication and improved nutrient intake compared with conventional and implant-based removable dentures in partial edentulism. However, no evidence is available regarding the effect of re-establishment of masticatory function with an implant-supported fixed prosthesis in edentulous patients.

Moreover, with the increasing evidence suggesting a positive impact of nutrition counselling on the dietary intake, brief dietary advice has been advocated to help patients make full use of the enhanced masticatory function to improve their diet. Ellis et al. further showed that the impact of dietary advice on patient's satisfaction with dentures and oral health-related quality of life depends on the nature of the prosthesis. No trial has been performed to assess the benefit of dietary advice only or the combined effect of re-establishment of masticatory function with an implant-supported fixed prosthesis and dietary advice in edentulous elderly subjects.

This is a 2 × 2 factorial clinical trial aimed to assess the effect of rehabilitation of masticatory function with fixed implant supported dentures and simultaneous diet re-education on the diet intake and nutrition in ageing subjects with terminal dentition (stage IV periodontitis) or full edentulism.

Eligibility Criteria:
Inclusion Criteria:

* being edentulous or having the presence of terminal dentition (defined as few remaining teeth insufficient in terms of number, position and health status to provide adequate anchorage to a tooth supported or a tooth retained denture) and looking for implant-supported fixed denture treatment
* accepted treatment plan for fixed implant-supported prosthesis restoring at least 10 pairs of occluding teeth
* self-reported inadequate vegetable or fruit or protein intakes (patients were included if at least one of the three criteria listed below were met) I. Patients with a total average daily intake of \< 80 g of poultry, meat and aquatic product. II. Patients with an average daily intake of \< 200 g of fruit. III. Patients with an average daily intake of \< 300 g of vegetables.
* understand written and spoken Chinese and who could respond to Chinese questionnaires
* able and willing to give informed consent for participation in the study
* able and willing to comply with 12-month follow-up

Exclusion Criteria:

* general contraindications to elective oral surgery procedures
* local contraindications to implant-supported immediate-loading fixed prosthesis (e.g. limited jaw opening, insufficient bone volumes/densities)
* looking for replacement of existing implant-retained overdenture with implant-supported fixed denture treatment
* presence of infectious disease, acute or chronic symptoms of TMJ disorder
* psychiatric disorder, dementia
* any dietary restriction, currently taking nutrient supplements or inability to choose his/her diet.
* uncontrolled diabetes (HbA1c≥7.0%)
* self-reported heavy smokers (\>10 cigarette/day)