The purpose of this study was to develop and validate the mouthwash use questionnaire to determine the lifetime exposure to alcohol from mouthwash and verify that it was suitable for use in general population.
Data were available from three consecutive studies, all collecting information on mouthwash use. In addition, supermarkets and online stores were screened for the brands of mouthwash they sold. Alcohol content of mouthwash was identified from various sources, including laboratory measurements. Alcohol-containing mouthwash use was converted to glasses of wine equivalent.
Mouthwash was used by 62% of the participants, and the main benefits reported were refreshment of bad breath (75%), elimination of bacteria (68%) and reduction of plaque formation (47%). Majority mouthwashes used by the participants contained alcohol (61%). Life-time exposure from alcohol in mouthwash was relatively small for most of the study participants: 79% had rinsed for less than one year with alcohol equivalent of one glass of wine per day. There was substantial agreement in mouthwash reporting between different occasions (Kappa > 0.62).
The questionnaire can be used to investigate mouthwash use in the general population and to measure alcohol intake from mouthwash.
Mouthwashes are fluids containing active components with antiseptic, antibiotic,
antifungal, astringent and anti-inflammatory effects on the oral cavity and pharynx
[
Various types of mouthwash are available on the market. They differ in content and as
such are tailored to specific requirements. Some of the key ingredients include
chlorhexidine gluconate, benzydamine hydrochloride, cetylpyridinium chloride, sodium
benzoate, triclosan, hydrogen peroxide, povidone-iodine, fluoride, sodium
bicarbonate, essential oils and ethanol [
Mouthwashes containing chlorhexidine gluconate currently have the status of a gold
standard for the inhibition of plaque formation and reduction of gingivitis [
In several commercial mouthwashes ethanol is added as a solvent for some of the
active properties mentioned above. At a high concentration ethanol also plays an
important role as a preservative and antiseptic agent [
Role of mouthwash in the development of oral cancer remains controversial. Several
studies showed conflicting results with some reporting an increased risk of
developing oral, pharyngeal and laryngeal cancers with regular mouthwash use [
Previous studies revealed that mouthwashes are used by the general population [
We attempted to develop a questionnaire to determine the lifetime exposure to alcohol from mouthwash and validate it in general population.
Ethical approval for the study was given by The College of Life Sciences and Medicine Ethics Review Board, University of Aberdeen.
Data were available from three consecutive studies: in each study questionnaires were
sent to participants of the preceding study (
Available data.
Pilot phase of the Grampian Adult Dental Health Survey [
Between July and November 2011 the full version of the Mouthwash Use Questionnaire (MUQ) was sent to the participants of the pilot phase who had agreed to be contacted again for further studies and had provided their contact details (Group 2).
MUQ consisted of twelve questions regarding mouthwash use, frequency of use, number of mouthfuls, dilution of mouthwash and the time the mouthwash is kept inside the mouth. Furthermore, participants were asked about their reasons for rinsing with mouthwash and the benefits they perceived from mouthwash use. In developing the questionnaire, particular interest was taken in collecting information on the alcohol content of different mouthwashes. Therefore, a question was included asking about the specific brand of mouthwash currently used by participants. A list with descriptions and coloured images of all mouthwashes available on the United Kingdom at that time market was provided as part of the questionnaire.
Participants who had filled in the MUQ and who had agreed to be contacted again for further research projects were used as controls in the Feasibility Study of Cancer of the Head and Neck, Genetics and Environment in Grampian (Group 3). For this case-control study a group of incident cases with cancer of the oral cavity, oropharynx and larynx identified from Aberdeen Royal Infirmary and a comparable group of controls were recruited between August and November 2011. All participants either filled in a lifestyle questionnaire at home, and returned it by post, or attended an interview with a trained research nurse where they completed the lifestyle questionnaire which included MUQ.
Alongside with these studies, large supermarkets and department stores in Aberdeen, Scotland, as well as several online stores were screened to determine which brands of mouthwash they sold.
The alcohol by volume (ABV) of each mouthwash was identified from labels, internet
sources, previous studies [
Ethanol content of 25 of the mouthwashes, for which there were no data on alcohol content, was examined in the laboratory using a headspace gas chromatography-flame ionisation detection (GC-FID) method. Chromatographic separation was performed on a dual column system (Rtx® - BAC1 and Rtx® - BAC2 columns; Restek, UK) at 40 °C with FID detection at 250 °C. An ethanol calibration curve was prepared ranging from 5 - 400 mg/dL using ethanol standard solutions at 400 and 200 mg/dL (Medichem Diagnostic, Germany). Linearity was observed with ethanol concentrations up to 400 mg/dL (y = 0.002x + 0.0034; r = 0.999).
The analytical and functional sensitivity of the assay were previously defined in-house as 1 mg/dL and 5 mg/dL, respectively. Internal ethanol quality control materials (Bio-Rad Laboratories, UK) levels 1 (49.3 - 61.3 mg/dL), 2 (141.6 - 161.6 mg/dL) were assessed at the beginning, middle and end of the assay run. Mouthwash was mixed with 2.4 M NaCl (1 : 9 dilution) containing n-propyl alcohol (5% v/v) as internal standard. Ethanol levels exceeding the linearity of the assay were diluted 1 : 100 in 2.4 M NaCl. The ethanol content of mouthwash was expressed as percent weight per volume (% w/v).
All statistical analysis was carried out using IBM® SPSS Statistics for Windows
version 19. Completed data from the three studies were merged and reported using
descriptive statistics. Kappa values and corresponding 95% confidence intervals (CI)
were determined using an online calculator available from:
Years of mouthwash use were calculated by using the age of participants when they filled in the questionnaire and their reported age when they started rinsing with their current mouthwash.
Glass of wine was used as a unit of analysis. One mouthful was considered equivalent
to 20 mL, which was in keeping with instructions for use provided by the most
popular mouthwash brands. The number of alcohol units of mouthwash was determined by
multiplying its ABV by 20 mL and dividing by 1000 mL. Numbers generated were then
multiplied by the number of mouthfuls participants used. One alcohol unit was
considered to equal half a standard glass (175 mL) of wine (ABV 12%) as suggested by
drinkaware.co.uk and Gill et al. [
Additionally, years rinsed with one glass of wine equivalent per day were calculated similar to pack-years of smoking. Number of glasses of wine equivalent rinsed per day were multiplied by years of usage.
Content validity was measured by investigating whether the most frequently used mouthwash brands by the study population were also the brands most often available in supermarkets and online stores. In addition, frequency of tooth brushing and flossing was compared to frequency of mouthwash use using Spearman correlation coefficient. MUQ was assessed for reliability by comparing information on mouthwash use from Group 2 to the data collected from Groups 1 and 3 using Kappa statistics.
The participation rate in the pilot phase of the Grampian Adult Dental Health Survey was 63% (300 individuals out of 480) (Group 1). Over half of the participants were female (n = 158, 53%). The mean age (standard deviation; SD) of the study population was 55.8 (16.8) years and ranged from 25 to 96 years.
132 of the original participants included in the pilot phase of the Grampian Adult Dental Health Survey received the full mouthwash use questionnaire. Of these, 73 (55%) participants returned completed questionnaires. Forty-five (62%) participants were female. The mean age was 54.1 (14.6) years and ranged from 27 to 80 years.
From Group 2 forty-eight participants were asked to serve as controls in the Feasibility Head and Neck Cancer Study. A completed lifestyle questionnaire was obtained from 26 participants (Group 3), leading to a participation rate of 54%. Fifteen (58%) participants were male and the mean age was 63.0 (10.2) years (Range 46 - 81 years).
In Group 2 twelve participants (16%) had never used mouthwash (
Mouthwash use
Characteristics | Group 2a |
Group 3b |
---|---|---|
Ever used mouthwash | ||
No | 12 (16.44) | 10 (38.46) |
Yes | 61 (83.56) | 16 (61.54) |
Current use of mouthwash | ||
Never used | 12 (16.44) | 10 (38.46) |
Used in the past | 16 (21.92) | 5 (19.23) |
Current use/1 year ago | 45 (61.64)c | 11 (42.31)d |
Years of using mouthwash | ||
≤ 5 years | 20 (58.82) | 1 (14.29) |
6 - 15 years | 8 (23.53) | 3 (42.86) |
16 - 25 years | 3 (8.82) | 2 (28.57) |
> 25 years | 3 (8.82) | 1 (14.29) |
Missing | 11 | 4 |
Frequency of use | ||
< Once/week | 11 (24.44) | 3 (27.27) |
Once or twice/week | 7 (15.56) | 2 (18.18) |
Every other day | 4 (8.89) | 1 (9.09) |
Once/day | 12 (26.67) | 2 (18.18) |
Twice/day | 11 (24.44) | 2 (18.18) |
Three times/day | - | 1 (9.09) |
Time interval between brushing teeth and use of mouthwash | ||
< 1 min | 29 (64.44) | 6 (54.55) |
About 5 min | 11 (24.44) | 3 (27.27) |
About 1 hour | 2 (4.44) | - |
About 2 hours | 1 (2.22) | - |
Other | 2 (4.44) | 2 (18.18) |
Dilute mouthwash | ||
No | 42 (93.33) | 9 (81.82) |
Yes | 3 (6.67) | 2 (18.18) |
Amount of mouthfuls | ||
Only one | 40 (88.89) | 11 (100) |
Two or more | 5 (11.11) | - |
Time kept in mouth | ||
A few seconds (≤ 20 sec.) | 19 (44.19) | 6 (54.55) |
Longer (> 20 sec.) | 24 (55.81) | 5 (45.45) |
Missing | 2 | - |
Swallow mouthwash | ||
No | 45 (100) | 11 (100) |
Yes | - | - |
Mouthwash contains alcohole | ||
No | 21 (51.22) | 3 (27.27) |
Yes | 25 (60.98) | 8 (72.73) |
Missing | 4 | - |
Glasses of wine equivalent rinsed per year (users of alcohol containing mouthwash) | ||
1 - 25 | 13 (52) | 5 (62.5) |
26 - 50 | 5 (20) | - |
51 - 100 | 3 (12) | 2 (25) |
101 - 150 | - | - |
151 - 200 | 3 (12) | - |
> 200 | 1 (4) | 1 (12.5) |
Years rinsed with one glass of wine equivalent per day (users of alcohol containing mouthwash) | ||
0.0 - 0.4 | 13 (68.42) | 2 (40) |
0.5 - 0.9 | 2 (10.53) | - |
1 - 1.9 | 2 (10.53) | 2 (40) |
2 - 2.9 | - | 1 (20) |
> 3 | 2 (10.53) | - |
Missing | 6 | 3 |
aGroup 2 are participants who filled in the mouthwash use questionnaire.
bGroup 3 are controls of the Feasibility Head and Neck Cancer Study.
cQuestionnaire asked for the current use of mouthwash.
dGroup 3 was asked about mouthwash use one year ago.
eNumbers do not add up to total, because 5 participants in the Mouthwash Use project used two different mouthwash brands.
The majority of participants rinsed with mouthwash either once (27%) or twice daily (24%). Nine percent rinsed every other day whilst 16% used mouthwash once or twice weekly. 24% of participants rinsed with mouthwash less than once weekly. Usually mouthwash was used within five minutes of brushing teeth. The majority of participants (89%) rinsed with one mouthful of mouthwash, 93% did not dilute the mouthwash and 56% of participants rinsed for more than 20 seconds. No one swallowed the mouthwash after use.
Twenty-one (51%) participants surveyed used mouthwash containing no ethanol. All other participants appeared to rinse with an alcohol-containing mouthwash (61%). These numbers do not add up to 100%, because five participants used two different mouthwash brands and were counted twice, while four participants did not report which brand they used.
The conversion of the amount of alcohol containing mouthwash rinsed by participants
into glasses of wine resulted in 52% rinsing with the equivalent of 1 to 25 wine
glasses per year. Four individuals rinsed with equivalent of more than 150 glasses
of wine per year. Numbers of years rinsed with one glass of wine equivalent per day
remained relatively small for most study participants. A majority of 68% had rinsed
less than half a year with one glass of wine per day. A further 11% remained under
one year (
When asked about the reasons for using mouthwash, 32 (71%) participants elected to
use it themselves. Ten participants stated that it was recommended by their dentist,
in three of these ten cases because of gum disease. The perceived benefit of
mouthwash use for most of the study population was refreshment of bad breath (75%).
This was followed closely by elimination of bacteria, reduction of plaque formation
and the ability to reach difficult places in the mouth (
Reasons and benefits of mouthwash use as suggested by study participants
Characteristics | Group 2a |
|||||
---|---|---|---|---|---|---|
Reasonsb | ||||||
Chosen by myself | 32 (71.11) | |||||
Recommended by a dentist | 10 (22.22) | |||||
Recommended by a doctor | 1 (2.22) | |||||
Receding gums and loose teeth | 1 (2.22) | |||||
Daughter uses it | 1 (2.22) | |||||
Recommended by a Chemist for sore throat + found it very effective | 1 (2.22) | |||||
Benefitsb | ||||||
Refreshment of bad breath | 55 (75.34) | |||||
Elimination of bacteria | 50 (68.49) | |||||
Reduction of plaque formation | 34 (46.58) | |||||
Ability to reach difficult places in the mouth | 33 (45.21) | |||||
Prevention of cavities | 24 (32.88) | |||||
Prevention of periodontitis and gingivitis | 21 (28.77) | |||||
Removal of tartar | 20 (27.40) | |||||
Improvement of oral wound healing | 19 (26.03) | |||||
Strengthening of tooth enamel | 16 (21.92) | |||||
General health improvement | 14 (19.18) | |||||
Reduction of dentine sensitivity | 13 (17.81) | |||||
Alleviation of oral pathology | 13 (17.81) | |||||
Relieve of pain | 10 (13.70) | |||||
Stain removal | 9 (12.33) | |||||
As a follow-up to oral surgery | 8 (10.96) | |||||
Relieve of dry mouth | 7 (9.59) | |||||
Reduction of frequency of tooth brushing | 4 (5.48) | |||||
As a gargle | 1 (1.37) | |||||
Heart protection | 1 (1.37) | |||||
Prevention of colds | 1 (1.37) | |||||
Refreshment of bad taste | 1 (1.37) |
aGroup 2 are participants who filled in the mouthwash use questionnaire.
bNumbers do not add up to total, because of multiple possible replies.
The most common brand of mouthwash used in Group 2 was Listerine (Johnson &
Johnson Limited, Maidenhead, UK) (30%) (
Mouthwash brands used by study participants according to shops where they are available
Mouthwash brand | |
Availability | ||
|
|
|
||
N (%)b | N (%) | N (%) | N (%) | |
Listerine | 14 (30.43) | 8 (100) | 9 (100) | 17 (100) |
Colgate | 7 (15.22) | 7 (87.5) | 7 (77.78) | 14 (82.35) |
Corsodyl | 6 (13.04) | 8 (100) | 7 (77.78) | 15 (88.24) |
Aquafresh | 5 (10.87) | 6 (75) | 8 (88.89) | 14 (82.35) |
Dentyl pH | 5 (10.87) | 8 (100) | 6 (66.67) | 14 (82.35) |
Retardex | 2 (4.35) | 7 (87.5) | 4 (44.44) | 11 (64.71) |
ASDA | 1 (2.17) | 1 (12.5) | 1 (11.11) | 2 (11.76) |
Boots | 1 (2.17) | 1 (12.5) | 1 (11.11) | 2 (11.76) |
Gengigel | 1 (2.17) | 2 (25) | 2 (22.22) | 4 (23.53) |
Optima | 1 (2.17) | 1 (12.5) | - | 1 (5.88) |
Oral-B | 1 (2.17) | 6 (75) | 6 (66.67) | 12 (70.59) |
Oraldene | 1 (2.17) | 5 (62.5) | 6 (66.67) | 11 (64.71) |
Sensodyne | 1 (2.17) | 6 (75) | 7 (77.78) | 13 (76.47) |
aGroup 2 are participants who filled in the mouthwash use questionnaire.
bNumbers do not add up to total, because five participants stated two mouthwash brands and four values were missing.
There was a significant relationship between frequency of mouthwash use and frequency of tooth brushing (Spearman correlation 0.14, P = 0.026) and flossing (Spearman correlation 0.16, P = 0.015).
Majority of participants who reported that they currently used mouthwash in the Pilot phase of the Grampian Adult Dental Health Survey also reported this in the mouthwash use questionnaire (85.7%). For frequency of use, substantial agreement was found comparing Group 1 and 2 (weighted Kappa = 0.62 [0.43, 0.77]).
Of the 21 individuals, who reported they had ever used mouthwash in the MUQ study, 15 (71.4%) also reported this in the Feasibility Head and Neck Cancer Study. When comparing frequency of mouthwash use on two occasions (Group 2 and 3), reliability was found to be substantial (Kappa = 0.77 [0.38, 0.97]). For these groups the alcohol content of the mouthwash brands used was also investigated. Data were only available for eight participants who gave the information in both studies. The overall agreement was found to be perfect (100%).
Mouthwash was commonly used among the study population and the majority of participants saw its benefit in the refreshing of bad breath. The most frequent mouthwash brands used by participants were widely available in a variety of supermarkets and online stores. More than half of the reported brands contained alcohol. There was substantial reliability in reporting frequency of use.
A limiting factor for the results of reliability of the questionnaire was the long time period between the Pilot Grampian Adult Dental Health Survey and the Mouthwash Use Project. During the two years between these studies, participants could certainly have changed their patterns of mouthwash use, leading to lower Kappa values. For use in the Feasibility Head and Neck Cancer Study, questions on mouthwash use had to be adapted to its specific study design. Therefore, all questions on mouthwash use asked for the patterns of use one year ago and not for the current state. This might also limit the results for reliability when comparing Groups 2 and 3.
The MUQ contained extensive questions on mouthwash use and, therefore, gives distinct information on the habits of participants, as well as their preferred brands. This makes it possible to collect information on the alcohol content of the mouthwashes. In this project, the alcohol content of mouthwash was expressed as glasses of wine. The numbers of glasses rinsed per year varied greatly among participants, but remained relatively small for the majority, as well as, years rinsed with one glass of wine equivalent per day.
Polesel et al. [
Very few studies which assessed the use of mouthwash and the associated risk of
cancer development have collected information on mouthwash brands used and alcohol
content [
Within a case series Weaver et al. [
The mouthwash use questionnaire, used in this study, combined all of these variables and, therefore, is an important tool for future studies examining the risks and benefits of mouthwash use. However, mouthwash brands did not always list the alcohol content on the labelling, making the exposure of the oral cavity to alcohol difficult to determine.
Further high-quality studies are required to differentiate the effects of alcohol-containing and alcohol-free mouthwash use on the development of on head and neck cancers. These studies should consider regression spline models as an option for examining dose-response relationships.
The mouthwash use questionnaire was proven to be a valid and reliable tool for the examination of mouthwash use in the general population. Future studies should support more accurate assessment of alcohol content in mouthwash which would allow oral cavity exposure to be determined as well as its associated risk for oral cancer development.
This project was partly supported by the NHS Grampian Endowment fund. We are very grateful to all participants for completing the questionnaires. Tanja Wirth worked on this project while taking part in an Erasmus student placement under the European Lifelong Learning Programme. Michal M. Kawecki was supported by HotStart scholarship. The authors report no conflict of interest related to this study.