Effect of Molar Replacement on Glycemic Control in Adults With Uncontrolled Type 2 Diabetes

Diabetes is one of the leading causes of death and disability worldwide. The current prevalence of the most common form of diabetes, type 2 diabetes (T2D), is estimated at 9.2% among individuals aged 20-79 years in Europe. First-line management of T2D relies on therapeutic lifestyle modifications (diet and physical activity), with pharmacological treatment added in case of failure. Despite the wide range of available pharmacological options, up to 50% of individuals living with T2D who adhere to treatment do not achieve their glycemic targets. There is therefore a need to identify alternative strategies to reduce blood glucose levels.

Individuals living with T2D generally have poorer oral health than the general population, with a reduced number of teeth and more frequent and severe periodontitis. This results in lower masticatory efficiency compared with the general population, as masticatory efficiency mainly depends on the number of teeth in occlusion, particularly the presence of premolars and molars. The persistence of at least one pair of first molars plays a major role in determining the ability to grind and mix food. Masticatory efficiency influences dietary choices.

It is currently unknown whether improving masticatory efficiency in individuals with uncontrolled diabetes, through the replacement of missing teeth, modifies dietary habits and improves diabetes control. The hypothesis of this study is that, in individuals with uncontrolled T2D, restoring masticatory efficiency by replacing missing molars with fixed implant-supported prostheses will lead to improved dietary quality and better glycemic control.

This is a multicenter, open-label, two-arm parallel-group, superiority randomized controlled trial. Participants will be randomized in a 1:1 ratio to receive either:

Intervention: replacement of one pair of molars with implant-supported prostheses in addition to standard care for the management of type 2 diabetes (T2D);

Control: standard care for the management of T2D only.

The primary objective is to evaluate the impact of replacing one pair of molars with implant-supported prostheses in individuals living with uncontrolled T2D and reduced masticatory efficiency, at 9 months post-randomization, on glycemic control.

The primary endpoint is the difference in HbA1c between randomization and 9 months post-randomization.

Regarding individual benefits, all patients included in the study will benefit from a comprehensive oral health assessment allowing screening for dental caries, dental infections, periodontal disease, oral mucosal pathologies (including pre-cancerous and cancerous lesions and oral candidiasis), xerostomia, malocclusion, and temporomandibular joint disorders. These conditions are more frequent in patients with T2D. All included patients will subsequently receive dental care aimed at eliminating infectious foci and treating any carious lesions and periodontal diseases that may be present. The assessment and dental care will improve patients' oral health and contribute to a better oral health-related quality of life. They may also potentially improve diabetes control, as infectious foci and periodontal diseases are responsible for local and systemic inflammation that complicates glycemic control.

For patients included in the intervention group, restoration of a functional molar pair in occlusion is expected to significantly increase masticatory efficiency and further improve oral health-related quality of life. The intervention may also lead to changes in dietary habits toward a healthier and more balanced diet. Such dietary changes could be beneficial for diabetes control. As reduced masticatory efficiency is associated with a higher risk of coronary heart disease, the intervention may also reduce the risk of cardiovascular disease. The implants and implant-supported prostheses used to restore a molar pair are provided as part of the research.

• Change in masticatory efficiency assessed by two-colour chewing gum mixing test (Variance of Hue) from randomization to 9 months post-randomization. [Time frame: 9 months]
• Subjective masticatory efficiency : Change in Chewing Function Questionnaire (CFQ) total score from randomization to 9 months post-randomization. [Time frame: 9 months]
• Change in weight, from randomization to 9 months post-randomization. [Time frame: 9 months]
• Change in body mass index from randomization to 9 months post-randomization. [Time frame: 9 months]
• Change in triglycerides from randomization to 9 months post-randomization. [Time frame: 9 months]
• Change in HDL cholesterol from randomization to 9 months post-randomization. [Time frame: 9 months]
• Change in total cholesterol from randomization to 9 months post-randomization. [Time frame: 9 months]
• Change in glucose Time in Range (TIR; 70-180 mg/dL) assessed by continuous glucose monitoring over 15 days from randomization to 9 months post-randomization. [Time frame: 9 months]
• HbA1c values at randomization and at 3 and 6 months post-randomization. [Time frame: 6 months]
• triglyceride values at randomization and at 3 and 6 months post-randomization. [Time frame: 6 months]
• HDL cholesterol values at randomization and at 3 and 6 months post-randomization. [Time frame: 6 months]
• Total cholesterol values at randomization and at 3 and 6 months post-randomization. [Time frame: 6 months]