Timing of Dietary Acid Intake, Brushing Teeth and Acid Erosion.
Conditions: Tooth Wear
Sponsor: King's College London

 
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Timing of dietary acid intake, brushing teeth and acid 
erosion  
NCT: NCT02449434 
 
Document Date: 3/12/2013 
 

 
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PROTOCOL TITLE: Timing of dietary acid intake, 
brushing teeth and acid erosion 
Questionnaire based study 
 
Sponsor 
Name: KCL Keith Brennan 
Address: Room 1.8 Hodgkin Building Guy’s Campus, KCL 
Telephone: 02078486960 
Fax: 
Email: keith.brennan@kcl.ac.uk 
Chief Investigator  
Name: Professor David  Bartlett 
Address: Floor 25, Tower Wing, Dental School, SE19RT 
Telephone: 02071885390 
Fax: 
Email: david.bartlett@kcl.ac.uk 
Name and address of Co-Investigator(s), Statistician, Laboratories etc 
Name: Dr Rebecca Moazzez 
Address: Floor 25, Tower Wing, Guy’s Campus, SE19RT 
Telephone: 02071881577 
Fax: 
 
Name: Dr Saoirse O’Toole 
Address: Floor 25, Tower Wing, Guy’s Campus, SE19RT 
Telephone: 02071885390 
Fax: 
Email:saoirse.otoole@kcl.ac.uk 
 
 
 

 
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Title   
 
Timing of dietary acid intake, brushing teeth and 
acid erosion 
Protocol Short Title/Acronym  
Brushing frequency and acid erosion 
Protocol Version number and Date 
 
 
Version 1 3/12/2013 
Study Phase if not mentioned in title 
 
 
Questionnaire study 
Study Duration 
 
 
3 years 
Methodology 
 
 
Questionnaire based study. 
Sponsor name 
 
 
KCL 
Chief Investigator 
 
 
Professor David  Bartlett 
REC number 
 
 
 
Medical condition or disease under 
investigation 
 
Dental erosion 
Purpose of clinical trial 
 
 
To determine if brushing teeth before or after 
consuming an acid drink causes the greatest wear 
Primary objective 
 
 
Current dietary and toothbrushing practice 
Secondary objective (s) 
 
 
Attitudes to brushing behaviour 
Number of Subjects/Patients  
600 
 
Trial Design  
 
 
Questionnaire on a convenient sample 
compared to matched control group 
Endpoints 
 
 
Saturation of data from one to one studies and 
work from previous research shows  600 should 
create statistical differencs 
Main Inclusion Criteria 
 
 
Tooth wear  
 
Statistical Methodology and Analysis 
 
 
Frequencies, Multivariate and univariate 
analysis 
 
 
 

 
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Protocol for Timing of dietary acid intake, brushing teeth and acid erosion 
 
Background 
Dental erosion is common with prevalence studies suggesting up to 30% of European adults 
showing signs and up to 10% of patients over 60 yrs justifying restorations.(1, 2)  The 
impact of tooth wear means restorations are beyond the confidence and training of most 
general dentists. Our previous work has shown that monitoring tooth wear over time shows 
periods of activity and inactivity and the most important risk factor is the frequency of acidic 
food/drink intake(3). Influencing dietary intake is challenging but modifying the behaviour 
is potentially more successful. A known risk in erosive tooth wear is consumption of acids 
and there is possibly a relationship between timing of acid intake and brushing teeth. This 
project will assess if a simple process such as brushing teeth before breakfast or meals 
containing acid is effective in making the teeth more resistant to acids. The main active agent 
is fluoride and its interaction with the tooth. Hypothetically, brushing the teeth before an 
acid challenge should increase the availability of fluoride to harden the tooth surface making 
it more resistance to demineralisation. Therefore the intention of this application is to 
redirect the emphasis of care away from expensive restorations back onto the patient and 
deliver prevention with a simple but effective habit change.  
 
Objectives 
This is a preliminary study investigating the relationship between timing of brushing and 
erosion. This part will collect basic data on the dietary habits of patients with and without 
erosion, timing of brushing and their feelings about the impact of wear on their teeth. 
Further work will subsequently investigate clinically the wear of teeth following acid 

 
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exposure and then tootbrushing before or after. At that time a separate ethics application 
will be made. 
 
Method 
The study group will consist of two cohorts, those presenting with tooth wear and a matched 
control group. The patient group will be recruited from a specialized referral clinic for 
patients with tooth wear. These patients are referred to the hospital for advice on the 
management of tooth wear. Relatively few patients are offered care and the majority are 
returned to their general dental practitioner for continuing care. Potential participants will 
be approached on the clinic at the beginning of their appointment, which tends to last 
around 90 minutes. They will be given the patient information sheet and asked to consider 
participating. Those accepting the request will be offered the opportunity to complete the 
questionnaire at the end of their appointment so as to reduce any inconvenience. 
Alternatively, if they prefer they will be given a separate appointment to their convenience 
at another day. For a small proportion of patients who agree to participate in the 1 to 1 
session they will be appointed at another time and their travel expenses provided. The 
control group will be recruited from open student or staff clinics where patient attend for 
their routine care. The same recruitment process will be followed but as this group may 
return to the hospital at a second visit the opportunity to complete the questionnaire will be 
at a future or their current visit and the decision reached at their convenience. 
 
Inclusion criteria 
1. Severe tooth wear with a BEWE score of 12 and at least one score of 3 in three 
quadrants 

 
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2. Adult 18 years or older 
3. No missing anterior teeth 
4. Minimum of at 10 teeth in the upper and 10 teeth in the lower jaw 
5. No anterior crowns/ bridges or implants 
6. Written consent to the study 
 
Exclusion criteria 
1. Pregnancy 
2. Participation in other research within 30 days 
3. Unable to speak or understand English 
4. Presence of periodontal disease or caries on more than one tooth 
The inclusion of patients is aimed at those who present with tooth wear and no other dental 
conditions such as missing teeth or periodontal disease or caries. The control participants 
will have the same inclusion and exclusion criteria apart from an absence of tooth wear. 
Questionnaire  
We will assess current habits using a proven dietary questionnaire(4). Unlike other 
questionnaires this computer programme provides an estimate of the dietary intake of fruit 
and Vitamin C within a week. Called the health and equality audit (HEA) the record has been 
used in dietary analysis by dentists and dieticians. The audit will provide an accurate record 
of the intake of acidic foods and drinks and their timing together with brushing habits which 
will then be compared to clinical findings of tooth wear.  The questionnaire will be slightly 
modified to assess the timing of brushing teeth and the presence of any symptoms of 
reflux/heartburn  
 

 
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Clinical assessment 
The clinical assessment of tooth wear is through a visual grading on a 4 point scale ranging, 
from 0 to 3 and published by our team, and then statistical comparison made to the intake of 
acid(2). The assessment will occur under good lighting, dry teeth and all teeth scored on all 
surfaces.  The scoring system has been utilized in a number of previously published studies. 
 
OHIP – modified oral health impact assessment 
This questionnaire, which has been previously used in a number of studies, assesses the 
impact of tooth wear on behavioral attitudes. There are a series of related questions 
assessing personal views on how the tooth wear affects their feeling about their teeth. 
 
Sample size 
Previous work from our group has shown statistical relationships between acid intake and 
risk factors on a convenient sample of adults. This cohort of 1010 adults were recruited from 
University Students who were then dentally examined and completed a questionnaire. The 
Odds ratio calculated from this sample showed relationship with fruit and drinking method. 
The odds ratio’s were both 1.4 and 5 respectively (5).  
 
Based on this data we predict a cohort of 300 patients with tooth wear and 300 controls 
should show statistical differences. There are no previous data to show outcome of OHIP.  
Adults aged 18 and over will be recruited provided they give consent and satisfy the 
inclusion and exclusion criteria. 
 
Analysis 
The data will be compared within and between groups, using non parametric analysis. In our 

 
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experience with patient based research these groups of analyses work well.  
Cases and controls will be compared in terms of their demographics, clinical characteristics 
and risk factors, using the Chi-square test for categorical variables and the t-test for 
continuous measures. Variables to be included in the logistic regression model will be 
manually selected based upon prior theory and the research hypothesis. Using the presence 
or absence of severe erosive wear (cases and controls) as the dependent variable, the 
unadjusted, sex-and-age- adjusted and fully adjusted associations of the included variables 
with erosive tooth wear will be estimated using unconditional binary logistic regression and 
reported using odds ratios (OR). As frequency matching does not require the use of 
conditional logistic regression during analysis, age (in the pre-defined groups), will be 
included as a potential confounder 
 
One to one interviews 
Approximately 10 participants from each group will be invited to a one to one interview to 
focus more completely on their feelings about tooth wear and its impact. The maximum of 
one hour interview will be conducted in an open style but with headings on (feelings about 
tooth wear, reasons why they sort care from their dentist, reasons for wanting the teeth 
restored, fears and concerns about dental care and any factors influencing care such as cost 
of care). The interview will be recorded on a digital tape and then transcribed by the clinical 
investigator at a later date. The data files will be stored on a encrypted computer. 
 
Outcome  
This study will hopefully improve our understanding of risk factors, which will then be 
possible to inform dentists and the public about the relationship between brushing and 
eating. Establishing dietary habits, their brushing habits and their level of tooth wear will 

 
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show current oral hygiene practices and show statistically the risk factors associated with 
when those with dental erosion brush their teeth. 
 
The study will be conducted in the clinical research unit at Kings College London Dental 
Institute at Guy’s Hospital. We have found that patients with erosion are very enthusiastic 
and dedicated to consider preventive approaches rather than restorative care which usually 
means a few years later the work needs to be replaced often to the personal expense of the 
patient. 
 
Finance 
The finance from this study will be provided by a grant held by the CI. We have also applied 
to the Shine Foundation but the study is not dependent upon this being successful. We 
anticipate that many of the possible participants will agree to have complete the 
questionnaire at their main NHS visit and will not need a subsequent one. However, if 
someone chooses to return or agrees to the one to one questionnaire travel expenses will be 
re-reimbursed.  
 
 
Reference List 
 
1. 
Smith BG, Bartlett DW, Robb ND. The prevalence, etiology and 
management of tooth wear in the United Kingdom. J Prosthet Dent 
1997;78(4):367-72. 
2. 
Bartlett DW, Lussi A, West NX, Bouchard P, Sanz M, Bourgeois D. 
Prevalence of tooth wear on buccal and lingual surfaces and possible risk factors 
in young European adults. J Dent 2013. 
3. 
Rodriguez JM, Austin RS, Bartlett DW. In vivo measurements of tooth 
wear over 12 months. Caries Res 2012;46(1):9-15. 
4. 
Bartlett DW, Maggio B, Targett D, Fenlon MR, Thomas J. A preliminary 
investigation into the use of denture adhesives combined with dietary advice to 
improve diets in complete denture wearers. J Dent 2013;41(2):143-7. 

 
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5. 
Bartlett D, Fares J, Shirodaria S, Chiu K, Ahmad N, Sherriff M. The 
association of tooth wear, diet and dietary habits in adults aged 18–30 years old. 
J Dent 2011;39(12):811-16.