The purpose of this clinical trial is to test a nutritional intervention. This study helps older adults who wear complete removable dentures improve their health. The main questions the study aims to answer are: * What are the participants life experiences living with complete dentures before the intervention? * Does the intervention improve the diet quality of the participants? * Does the intervention improve nutritional status of the participants? * Does the intervention improve chewing performance and muscle strength? * Does the intervention increase the thickness of the masticatory muscles? * Does the intervention improve stress and muscle health markers in saliva? * Does the intervention improve cognitive performance and oral health-related quality of life? * Does the intervention improve cerebral blood flow? The study will include a total of 40 participants, who will be assigned to two groups. One group of 20 participants will receive the nutritional intervention, while the other group of 20 participants will maintain their usual diet during the study period. This comparison will allow the investigators to assess the effectiveness of the intervention. Participants will: * Take part in a personal interview about their life experience with dentures. * Follow a dietary guide with recommendations on specific food textures for six months. * Receive personalized nutritional counseling and participate in healthy cooking workshops. * Use a custom-built mobile application to access the educational content of the nutritional guide, view instructional videos uploaded biweekly, and receive automated reminder notifications. * Attend clinical follow-up assessments, including chewing performance, muscle assessment, saliva markers, assessment of diet quality and nutritional status, cognitive tests, and oral health-related quality of life. * Complete these assessments at three main time points: baseline, 3 months, and 6 months.
This clinical trial evaluates the effectiveness of a multidimensional nutritional intervention on the functional, physiological, and cognitive health of older adults wearing complete removable dentures. The study employs a convergent parallel mixed-methods design to integrate quantitative with qualitative outcomes. 1. Methodological Evaluation Protocols Participants will undergo comprehensive clinical and laboratory assessments: * Masticatory Function and Muscle Health: Chewing kinematics will be evaluated using 3D electromagnetic articulography (3D-EMA). Maximum bite force will be measured with a digital gnatodynamometer. Masticatory performance will be determined through a standardized peanut-sieving method. Additionally, masseter and temporalis muscle thickness will be assessed via ultrasonography. * Salivary Biomarkers: Saliva samples will be collected to quantify markers of physiological stress and muscle health: Cortisol, Insulin-like Growth Factor 1 (IGF-1), and Creatine Kinase (CK). Oxidative stress and antioxidant capacity will be analyzed using ROS, DPPH, and ORAC parameters. * Baseline Sociodemographic Characteristics: Sociodemographic characteristics will be collected at baseline using a structured questionnaire. The questionnaire will include information on age, sex, educational level, marital status, occupation or employment status, income level, and other relevant background variables. * Nutritional Status Assessment: Nutritional status will be monitored monthly through anthropometric measurements and body composition assessment. These include weight, height, body mass index (BMI), waist circumference, and body fat percentage determined by bioelectrical impedance analysis (BIA). * Cognitive Performance and Cerebral Blood Flow: Cognitive tasks will be evaluated using the Addenbrooke's Cognitive Examination-Revised (ACE-R) and a digital Stroop test to measure attention and executive function. Additionally, transcranial Doppler ultrasonography will be used to monitor cerebral blood flow. * Qualitative Dimension: Individual semi-structured interviews based on Grounded Theory will explore participants' life experiences regarding tooth loss, denture adaptation, and psychosocial barriers before and after the intervention. 2. Intervention Logistics and Groups The 40 participants will be randomly allocated into two balanced groups (20 participants per arm): * Intervention Group: Participants will receive a 6-month educational nutritional intervention. This will include in-person nutritional counseling before starting the intervention, and again during the 3rd and 6th months. In addition, telephone nutritional counseling will be provided during the 4th and 5th months. All counseling sessions will be delivered by a trained nutritionist. During the first nutritional counseling session, participants will receive a dietary guideline booklet for users of removable dentures. This guide was developed based on the results of the first stage of the project and promotes foods that support chewing function, as well as adherence to a Chilean-adapted Mediterranean diet. The guideline will also include healthy recipes. During the 2nd month of the study, participants will be invited to attend a practical workshop led by a nutritionist and a chef, where they will prepare recipes included in the dietary guide. All participants in the intervention group will receive a monthly food box containing non-perishable components of the diet. This intervention is complemented by a custom-developed mobile application tailored to meet the study's requirements. Through this app, participants can access the full nutritional guide in PDF format, view new educational and instructional videos uploaded biweekly, and receive automated push notifications as reminders to enhance usability and compliance. * Control Group: Participants will maintain their usual diet for 6 months and undergo the same follow-up assessments as the intervention group. To ensure ethical equity, at the end of the intervention, all participants in the control group will receive one food box, the dietary guideline for users of removable dentures, access to the mobile application, and will be invited to attend a practical workshop led by a nutritionist and a chef.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
40
This 6-month nutritional intervention for older adults wearing complete removable dentures consists of 6 components: 1. In-person nutritional consultation: A trained nutritionist will provide dietary guidance, adapt recommendations to individual needs and support the initiation of dietary changes. 2. Telephone follow-up: Monthly counseling sessions to monitor progress, address question and reinforce adherence to the intervention. 3. Dietary guidelines booklet: Includes specific nutritional recommendations, weekly menu proposals, healthy recipes and guidance for incorporating foods with different textures and hardness levels, with the aim of stimulating masticatory function according to individual tolerance. 4. Cooking workshop: Will teach participants how to prepare the recipes included in the dietary guidelines booklet. 5. Food box delivery: Monthly supply of non-perishable ingredients. 6. Mobile app: Digital tool providing the digital guide, educational videos and push notifications.
Universidad de La Frontera
Temuco, Cautín, Chile
RECRUITINGMasticatory Performance
Measurement of food fractionation capacity. Participants will chew a standardized food (peanuts) for 20 cycles; the particles will be dried and processed through a sieving system (sieves from 4.0 mm to 870 μm) to determine the percentage of fractionation.
Time frame: T0 (month 0), T1 (month 3) and T2 (month 6).
Diet Quality Assessment
Diet quality will be assessed using the Chilean Healthy Eating Index (Índice de Dieta Mediterránea for Chile, IDM-Chile), which allows the evaluation of adherence to healthy dietary patterns in the study population.
Time frame: T0 (month 0), T1 (month 3) and T2 (month 6).
Perceptions of Edentulism and Adaptation to Complete Removable Dentures
A qualitative assessment using a Grounded Theory framework conducted through semi-structured individual interviews to explore older adults' perceptions regarding their experiences with tooth loss, rehabilitation with complete removable dental prostheses, and their natural functional and social adaptation strategies in daily life. Interviews (30-60 minutes) will be audio-recorded, transcribed verbatim, and analyzed concurrently using ATLAS.ti software through progressive coding (open, axial, and selective) to develop a substantive explanatory model.
Time frame: Between month 0 and month 1 (collected during the initial phase of the study to capture prior experiences and avoid intervention bias).
Masticatory Kinematics: Number of Chewing Cycles
The total number of chewing cycles recorded during the mastication of a standardized food (peanuts), quantified using a 3D electromagnetic articulograph (AG501).
Time frame: T0 (month 0), T1 (month 3) and T2 (month 6).
Masticatory Kinematics: Chewing Cycle Area
Assessment of chewing cycles focusing on the area, measured in square millimeters (mm²) using a 3D electromagnetic articulograph (AG501).
Time frame: T0 (month 0), T1 (month 3) and T2 (month 6).
Masticatory Kinematics: Masticatory Frequency
Assessment of the masticatory frequency during mastication, measured as the number of cycles per second (cycles/s) using a 3D electromagnetic articulograph (AG501).
Time frame: T0 (month 0), T1 (month 3) and T2 (month 6).
Masticatory Kinematics: Masticatory Speed
Assessment of chewing focusing on the movement velocity, measured in millimeters per second (mm/s) using a 3D electromagnetic articulograph (AG501).
Time frame: T0 (month 0), T1 (month 3) and T2 (month 6).
Maximum Bite Force
Measurement of maximum voluntary contraction in Newtons (N) using a digital gnathodynamometer placed between the first prosthetic molars.
Time frame: T0 (month 0), T1 (month 3) and T2 (month 6).
Masticatory Muscles Thickness
Evaluation of the thickness of the masseter and anterior temporalis muscles, measured in millimeters (mm) using a portable ultrasound device with a linear transducer.
Time frame: T0 (month 0) and T2 (month 6).
Salivary Biomarkers: Cortisol
Laboratory analysis of saliva samples to quantify cortisol concentration, a biomarker of physiological stress, samples will be analyzed using a Synergy HT Multimodal Reader (Biotek, USA). The outcome will be determined via enzyme-linked immunosorbent assay (ELISA) and expressed in nanograms per milliliter (ng/mL).
Time frame: T0 (month 0) and T2 (month 6).
Salivary Biomarkers: Insulin-like Growth Factor 1 (IGF-1)
Laboratory analysis of saliva samples to quantify Insulin-like Growth Factor 1 (IGF-1) concentration, a biomarker related to muscle health and growth, samples will be analyzed using a Synergy HT Multimodal Reader (Biotek, USA). The outcome will be determined via immunoassay and expressed in picograms per milliliter (pg/mL).
Time frame: T0 (month 0) and T2 (month 6).
Salivary Biomarkers: Creatine Kinase (CK)
Laboratory analysis of saliva samples to quantify Creatine Kinase (CK) enzymatic activity, a biomarker of muscle tissue stress and health, samples will be analyzed using a Synergy HT Multimodal Reader (Biotek, USA). The outcome will be determined via spectrophotometry and expressed in Units per liter (U/L).
Time frame: T0 (month 0) and T2 (month 6).
Salivary Biomarkers: General Oxidative Stress (ROS)
Laboratory analysis of saliva samples to quantify general oxidative stress by measuring reactive oxygen species (ROS) content. Saliva samples will be incubated with the CH2DCFDA fluorescent probe (30 uM) for 1 hour at 37°C in the dark. Fluorescence emission will be recorded at 530 nm using a Synergy HT multimodal reader (Biotek, USA), with H2O2 (100 uM) used as a positive control. The outcome will be reported as fluorescence intensity measured in Relative Fluorescence Units (RFU), where higher RFU values indicate a higher level of general oxidative stress.
Time frame: T0 (month 0) and T2 (month 6).
Salivary Biomarkers: Total Antioxidant Capacity (TAC)
Laboratory analysis of saliva samples to quantify total antioxidant capacity using the Oxygen Radical Absorbance Capacity (ORAC) method. The assay monitors the decay of fluorescein fluorescence (excitation/emission at 495/530 nm) over 120 minutes induced by AAPH free radicals, which is counteracted by the antioxidants in the sample. Readings will be captured every 2 minutes using a Synergy HT Multimodal Reader (Biotek, USA) and interpolated against a Trolox calibration curve. The outcome will be reported in millimoles of Trolox equivalents per milliliter of saliva (mmol TE/mL), where higher ORAC values indicate a greater total antioxidant capacity.
Time frame: T0 (month 0) and T2 (month 6).
Oral Health-Related Quality of Life
Evaluation of the impact of oral health on the patient's quality of life using the OHIP-7Sp questionnaire, validated for the elderly Chilean population. Total scores range from 0 to 28, where higher scores indicate poorer oral health-related quality of life.
Time frame: T0 (month 0), T1 (month 3) and T2 (month 6).
Cognitive Performance: Addenbrooke's Cognitive Examination (ACE)
Evaluation of global cognitive status and its subdomains (orientation, attention, memory, language, and visuospatial skills) using the Chilean version of the Addenbrooke's Cognitive Examination (ACE). The outcome is measured using the instrument's total score, which ranges from 0 to 100 points, where higher scores indicate better global cognitive efficiency.
Time frame: T0 (month 0), T1 (month 3) and T2 (Month 6).
Cognitive Performance: Stroop Test
Evaluation of executive functions, including selective attention, cognitive flexibility, inhibition, and information processing speed, administered digitally via the "EncephalApp-Stroop Test" application on a tablet. The outcome is measured as the total completion time in seconds, where shorter execution times indicate better executive performance and cognitive control.
Time frame: T0 (month 0), T1 (month 3) and T2 (month 6).
Cerebral Blood Flow: Mean Flow Velocity
Assessment of cerebral hemodynamics at rest focusing on the mean flow velocity of the anterior and middle cerebral arteries to evaluate neurovascular coupling. Measurements will be recorded in centimeters per second (cm/s) through Transcranial Doppler ultrasonography using a PMD-100 system (Spencer Technologies, Redmond, USA) with a 2 MHz transducer at a depth of 5 cm. The assessment will be conducted by a specialized neurologist at the neurology service of the Dr. Hernán Henríquez Aravena Hospital (Temuco, Chile).
Time frame: T0 (month 0) and T2 (month 6).
Cerebral Blood Flow: Pulsatility Index
Assessment of cerebral hemodynamics at rest focusing on the pulsatility of the anterior and middle cerebral arteries to evaluate neurovascular coupling and cerebrovascular resistance. The outcome will be calculated as a dimensionless ratio value through Transcranial Doppler ultrasonography using a PMD-100 system (Spencer Technologies, Redmond, USA) with a 2 MHz transducer at a depth of 5 cm. The assessment will be conducted by a specialized neurologist at the neurology service of the Dr. Hernán Henríquez Aravena Hospital (Temuco, Chile).
Time frame: T0 (month 0) and T2 (month 6).
Nutritional Status: Body Mass Index (BMI)
Anthropometric evaluation of nutritional status. Participants weight (measured in kilograms) and height (measured in meters) will be aggregated to calculate and report the Body Mass Index (BMI), expressed in kilograms per square meter (kg/m²).
Time frame: T0 (month 0), T1 (month 3) and T2 (month 6).
Nutritional Status: Waist Circumference
Anthropometric assessment of abdominal fat distribution. Measurement of the participant's waist circumference, recorded in centimeters (cm) using a standardized non-elastic flexible tape measure.
Time frame: T0 (month 0), T1 (month 3), and T2 (month 6).
Body Composition: Body Fat Percentage
Evaluation of tissue body composition, specifically assessing the total body fat percentage (%), determined via bioelectrical impedance analysis (BIA).
Time frame: T0 (month 0), T1 (month 3) and T2 (month 6).
Body Composition: Skeletal Muscle Mass Percentage
Evaluation of muscular health and body composition, specifically assessing the skeletal muscle mass percentage (%), determined via bioelectrical impedance analysis (BIA).
Time frame: T0 (month 0), T1 (month 3) and T2 (month 6).
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