Plain English Summary
Background and study aims
Soy drinks are often promoted as healthy alternatives to cow's milk even though they can contain added sugar. This study will compare the mineral content of tooth enamel after consumption of cow's milk or a soy drink to investigate the effect of these drinks on teeth.
Who can participate?
Healthy staff and students of the University of Melbourne, aged 18-60 years.
What does the study involve?
Human enamel pieces cut from extracted third molar (wisdom) teeth with artificially-created subsurface lesions (early tooth decay lesions) are prepared and inserted into intra-oral palatal appliances (similar to removable partial dentures) that are worn by the participants. A 200 ml sample of soy drink or cow's milk will be consumed once per day for 15 days. The participants will be randomly assigned one drink for the intervention period, and then after one week where they will not insert the appliance will cross-over to consume the other drink. The drinks are commercially available in Australia. Enamel lesion mineral content of the enamel pieces in the worn appliances will be measured after each 15-day treatment in the laboratory after the enamel pieces are removed.
What are the possible benefits and risks of participating?
The expected benefit of the study is that it will provide important information on each type of drink's ability to encourage tooth decay. It is expected that milk is better than soy drink in helping to repair tooth decay lesions. There is very little risk for the participants as both of the beverages are safe for human use.
Where is the study run from?
University of Melbourne (Australia)
When is the study starting and how long is it expected to run for?
June 2018 to November 2018
Who is funding the study?
Department of Industry, Innovation and Science, Australian Government
Who is the main contact?
Prof. Eric Reynolds, e.reynolds@unimelb.edu.au
Trial website
Contact information
Type
Scientific
Primary contact
Prof Eric Reynolds
ORCID ID
http://orcid.org/0000-0002-6618-4856
Contact details
Level 6
720 Swanston Street
Carlton
3053
Australia
63 1 9341 1547
e.reynolds@unimelb.edu.au
Additional identifiers
EudraCT number
ClinicalTrials.gov number
Protocol/serial number
University of Melbourne ID 1750501
Study information
Scientific title
Effects of soy and bovine milk beverages on enamel mineral content in a randomized, double-blind in situ clinical study
Acronym
Beverage in situ clinical trial
Study hypothesis
Milk is superior to a soy beverage in remineralization of tooth enamel subsurface lesions in situ.
Ethics approval
Approved 20/04/2018, University of Melbourne Medicine and Dentistry Human Ethics Sub-Committee (University of Melbourne, VIC 3010; +61 38344 1539), ref: 1750501
Study design
Single-centre double-blind randomized cross-over trial
Primary study design
Interventional
Secondary study design
Randomised cross over trial
Trial setting
Community
Trial type
Treatment
Patient information sheet
Not available in web format, please use the contact details to request a participant information sheet.
Condition
Dental caries (tooth decay)
Intervention
The double-blind, randomized, cross-over in situ clinical trial was conducted at the Royal Dental Hospital of Melbourne in 2018. Participants were randomly assigned to one of the two different test products and crossed over to the other test products with one week washout in between. Each participant was assigned a number and randomization was effected using a standard randomization table for the coded test products. Each participant wore the custom-made palatal appliance containing four enamel half-slabs with subsurface lesions and once per day for 15 days consumed 200 ml of test product. The product consumption involved 10 -15 sips of the beverage over 60 seconds allowing the beverage during each sip to contact the enamel slabs in their appliance. Participants kept a diary of beverage consumption times and duration. Participants maintained their normal diet and oral hygiene procedures for the duration of the study, however the intra-oral appliances were removed during eating and drinking (except for the test beverage) and normal oral hygiene procedures. When out of the mouth the appliances were stored in sealed humid containers. All subjects brushed their teeth with standard 1450 ppm fluoride toothpaste for the duration of the study. The subjects returned to the clinical site with their appliances, diary and empty tubes at the conclusion of each 15-day treatment period. Researchers and participants were blind to the treatment code. An independent staff member held the treatment code which was only released after data collection and analysis. After each treatment period each test half-slab was paired with its control half-slab and embedded, sectioned and analysed by transverse microradiography to determine mineral content as described previously by Cochrane et al. (2012).
Intervention type
Supplement
Phase
Drug names
Primary outcome measure
Integrated mineral gain/loss, ΔZd-ΔZr. At the end of each treatment period each test half-slab will be paired with its control half-slab and embedded, sectioned and analysed by transverse microradiography to determine mineral content as described previously (Cochrane et al. 2012). Lesion parameters, lesion depth (LD) and integrated mineral loss (ΔZ) will be determined and the ΔZ value for the control demineralized lesion will be designated ΔZd and that for the treated lesion will be designated ΔZr. These values will then be used to calculate total mineral loss or gain ΔZd-ΔZr and percentage mineral change (%R) as (ΔZd-ΔZr/ΔZd) x 100.
Secondary outcome measures
Lesion depth (LDd-LDr). At the end of each treatment period each test half-slab will be paired with its control half-slab and embedded, sectioned and analysed by transverse microradiography to determine lesion depth (LD) as described previously (Cochrane et al. 2012). Lesion depth (LD) will be determined for the control demineralized lesion and will be designated LDd and that for the treated lesion will be designated LDr. These values will then be used to calculate the change in lesion depth will be calculated as LDd-LDr.
Overall trial start date
01/06/2018
Overall trial end date
30/11/2018
Reason abandoned (if study stopped)
Eligibility
Participant inclusion criteria
1. Healthy adults living in Melbourne, Australia, with a fluoridated (0.9 ppm F), reticulated water supply
2. Staff and students of the University of Melbourne
3. Aged 18-60 years
4. At least 22 natural teeth
5. Unstimulated whole salivary flow rate of ≥0.2 ml/min
6. Gum-stimulated whole salivary flow rate ≥1.0 ml/min
Participant type
Healthy volunteer
Age group
Adult
Gender
Both
Target number of participants
8
Participant exclusion criteria
1. Currently using antibiotics or medications that may affect salivary flow rates
2. History of severe oral disease
Recruitment start date
01/07/2018
Recruitment end date
31/08/2018
Locations
Countries of recruitment
Australia
Trial participating centre
University of Melbourne
Level 6, 720 Swanston Street
Carlton
3053
Australia
Sponsor information
Organisation
The University of Melbourne
Sponsor details
Professor Mike Morgan
Head
Melbourne Dental School
Faculty of Medicine
Dentistry and Health Sciences
University of Melbourne
Melbourne
VIC 3010
Australia
+61 3 9341 1546
m.morgan@unimelb.edu.au
Sponsor type
University/education
Website
Funders
Funder type
Government
Funder name
Department of Industry, Innovation and Science, Australian Government
Alternative name(s)
Department of Industry, Innovation and Science
Funding Body Type
government organisation
Funding Body Subtype
National government
Location
Australia
Results and Publications
Publication and dissemination plan
Planned publication in a high-impact peer-reviewed dental journal.
IPD sharing statement
No personal data on the participants will be provided only enamel mineral content data of the enamel pieces worn in the appliances by each participant after treatment with the various beverages. This information will be made available when the study is published. Prof. Eric Reynolds can be contacted for that information. The participants did provide informed consent in writing to be part of the study.
Intention to publish date
01/04/2019
Participant level data
Available on request
Basic results (scientific)
Publication list