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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Retrospectively registered

Titles & IDs
Public title
Effect of a chewing gum on growth of dental plaque and gum inflammation in the presence of oral hygiene: A Pilot Study.
Scientific title
Effect of a Sugar-free Chewing Gum containing Casein Phosphopeptide-Amorphous Calcium Phosphate (CPP-ACP) on Supragingival Plaque Composition in the Presence of Normal Oral Hygiene Procedures in Healthy Adults.
Secondary ID [1] 290782 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Gingivitis 301395 0
Supragingival dental plaque formation and microbial composition of supragingival plaque. 301396 0
Condition category
Condition code
Oral and Gastrointestinal 301140 301140 0 0
Other diseases of the mouth, teeth, oesophagus, digestive system including liver and colon

Study type
Description of intervention(s) / exposure
Participants will be asked to chew one slab of two different sugar-free gums containing two different levels of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) for 20 minutes, six times a day for 14 days each (two separate 14-day treatment periods), and not chew gum at all for 14 days ("no-gum" 14-day treatment period). Each participant will complete each treatment with two 14-day rest periods between treatment periods. The order of treatments will be random. One gum will contain 56.4 mg CPP-ACP per two pellets or one slab and the other will contain 18.8 mg CPP-ACP per two pellets or one slab of gum. During the week prior to commencement of the first treatment period, during each 14-day treatment period and during the two intervening 14-day rest periods, participants will be instructed to brush their teeth twice a day with a sodium fluoride toothpaste (1000 ppm fluoride) (toothpaste and brush supplied) but will be instructed not to use any other oral hygiene aids such as toothpicks, floss or mouthrinses and not to chew with any other gum. At the beginning and end of each treatment period, participants will have their gums examined to score the level of gingivitis and will also have supragingival plaque levels measured using a plaque-disclosing dye. They will then have all dental plaque removed from the cheek-facing surfaces of the crowns of their first and second upper molars, which will be later analysed for microbial composition. They will then have all supragingival plaque removed from all remaining teeth (professional scale and clean). At the end of the study they will also have a professional fluoride treatment . All dental examinations, plaque sampling, tooth cleaning and fluoride treatments will be conducted by a qualified dentist on the research team. Participants will return all used and unused gum wrappers at the end of the two treatment periods they chew one of the two gum products.
Intervention code [1] 296694 0
Treatment: Other
Comparator / control treatment
The control treatment for the two gums will be the "no gum" chewing treatment Each participant will cross-over to each of the three treatments so will act as their own controls.
Control group

Primary outcome [1] 300543 0
Development of gingivitis measured using the Modified Gingival Index.
Timepoint [1] 300543 0
End of each 14-day treatment period.
Secondary outcome [1] 330281 0
Growth of supragingival plaque measured using the Turesky modification of the Quigley-Hein Index (plaque stained with a proprietary disclosing dye)..
Timepoint [1] 330281 0
End of each 14-day treatment period.
Secondary outcome [2] 330282 0
Change in microbial composition of supragingival plaque on maxillary molar teeth.
Timepoint [2] 330282 0
End of each 14-day treatment period.

Key inclusion criteria
1. Ability to understand, and willingness and ability to read and sign, the informed consent form.
2. Age range: 18 to 65 years old.
3. Good general health.
4. Minimum of 20 natural teeth.
5. A gum-stimulated whole salivary flow rate greater than or equal to 1.0 ml/minute and unstimulated whole salivary flow rate greater than or equal to 0.2 ml/minute.
6. Willingness to comply with all study procedures and be available for the duration of the study.

Minimum age
18 Years
Maximum age
65 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
1. Allergy to milk protein or other ingredients in the gum product.
2. Orthodontic appliances or removable prostheses.
3. Veneers, or more than one incisor with a prosthetic crown.
4. Gross oral pathology (including periodontal disease (CPITN score greater than or equal to 3) and tumours of the soft or hard oral tissues).
5. Chronic disease with concomitant oral manifestations (e.g., diabetes [irrespective of level of control], human immunodeficiency virus infection or acquired immunodeficiency syndrome, use of medications associated with gingival hyperplasia).
6. Unrestored dentinal caries.
7. Treatment with antibiotics or anti-inflammatory medication in the month prior to starting the study.
8. Concomitant pharmacotherapy with drugs that may interact with test substance.
9. History of conditions requiring antibiotic coverage prior to invasive dental procedures.
10. Pregnancy/lactation.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation is not concealed.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
By a randomisation table created by computer software using block randomisation so that each sequence selected is equally likely.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
The range of means and standard deviations used in the sample size calculations was based on the previous pilot study. In that study, the mean difference in abundance of S. sanguinis between the CPP-ACP gum and the control gum was 1.87% and the standard deviation of the difference was 4.73%. Sample size calculation was based on the paired t-test with alpha = 0.05, power = 0.8 and an estimated attrition rate of 10%. Assuming a standard deviation of 4.5% and a 10% percent attrition rate, a sample of at least 18 participants was deemed necessary to allow for a mean difference in abundance of S. sanguinis of 3.5% to be detected with a power of 80 percent. Differences in the outcome measures: Turesky modification of the Quigley-Hein Index for the plaque levels, the Modified Gingival Index for severity of gingivitis and changes in bacterial composition (such as for the species S.sanguinis) will be measured using a two-tailed test for repeated measures. Differences in the saliva bacterial community over time will be determined by measuring the changes in the relative abundances of bacterial species for each participant.
This will enable a comparison of the effect of CPP-ACP on the bacterial composition of the plaque. The four plaque samples from each individual will enable determination of intra-participant variation in bacterial composition of plaque. The incidence of adverse events will also be measured and differences measured between treatment groups were measured using Cochrane-Mantel-Haentzel test where necessary.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment hospital [1] 7168 0
The Royal Dental Hospital of Melbourne - Carlton
Recruitment postcode(s) [1] 14927 0
3052 - Melbourne University
Recruitment postcode(s) [2] 14928 0
3053 - Carlton

Funding & Sponsors
Funding source category [1] 295201 0
Other Collaborative groups
Name [1] 295201 0
Oral Health CRC
Address [1] 295201 0
720 Swanston St Carlton VIC 3052
Country [1] 295201 0
Primary sponsor type
University of Melbourne
The University of Melbourne Parkville VIC 3010
Secondary sponsor category [1] 294033 0
Name [1] 294033 0
Address [1] 294033 0
Country [1] 294033 0

Ethics approval
Ethics application status
Ethics committee name [1] 296553 0
University of Melbourne Human Research Ethics Committee
Ethics committee address [1] 296553 0
Level 5 MUPL Building, 161 Barry Street, University Square, Carlton, Victoria 3052
Ethics committee country [1] 296553 0
Date submitted for ethics approval [1] 296553 0
Approval date [1] 296553 0
Ethics approval number [1] 296553 0

Brief summary
There is evidence that casein, a major protein in milk, combined with calcium and phosphate, called CPP-ACP may inhibit growth of dental plaque, alter the bacterial composition of plaque and inhibit development of gum inflammation. A large clinical study has been proposed, which will measure the effects of chewing gum containing CPP-ACP on dental plaque growth, plaque bacterial composition and gum inflammation. A previous pilot study compared the effect of chewing gum containing and not containing CPP-ACP in the absence of all oral hygiene. In order to further determine whether this study is feasible, a smaller scale study (pilot study) is required to be conducted that will compare the effects of gum containing two different amounts of CPP-ACP on these parameters in the presence of oral hygiene.
The aims of this pilot study are to compare re-growth of dental plaque, changes in bacterial composition of plaque, and development of gum inflammation after chewing with two sugar-free gums containing two different amounts of CPP-ACP and no gum chewing at all, each for 14 days each, with concomitant twice daily toothbrushing with fluoride toothpaste.
Eighteen adult participants will be recruited from staff and students of the Melbourne Dental Schools and their friends and family. Potential participants will first be screened by filling out a health questionnaire, having a dental examination by a qualified dentist on the research team, and providing two saliva samples; one at rest and one while chewing sugar-free gum, for two minutes each to ensure they produce normal amounts of saliva. These procedures will ensure participants will have no medical or dental conditions that might put them at risk by participating in this study.
There will be three 14-day treatment periods, during which participants will complete a different treatment. The treatment periods will be separated by two 14-day rest periods. For one week prior to the first treatment period and for each treatment and rest period, participants will brush their teeth twice daily with fluoride toothpaste and abstain from using any other oral hygiene aids; e.g. toothpicks, floss, mouthrinses and will not chew with any gums other than their allocated gums during the treatment periods. The order of the three treatments will be random for each participant and unknown to researchers analysing the results. If they are chewing gum, they will chew one slab or two pellets of their allocated gum six times a day for 20 minutes each time. If they are not chewing gum they will just brush their teeth twice daily and abstain from all oral hygiene practices and not chew any other gum. The identity of the gums will be unknown to the participants
At the start and end of each treatment period, participants will have a dental examination by the dentist on the research team to measure plaque (by staining their teeth with a plaque disclosing dye) and measure the amount of gum inflammation by visual inspection. They will also have plaque above the gums collected from all four upper molar teeth, which will be analysed for bacterial composition. They will then have all their teeth cleaned by the dentist, At the end of the study they will also have a professional fluoride treatment.
Participants will be instructed to contact the research team if they experience any problems during the study so that a qualified dentist on the team can assess and deal with the problem accordingly. Participants will be paid for their time and commitment to the study and will be free to exit the study at any time.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 71266 0
Prof Eric C. Reynolds
Address 71266 0
Melbourne Dental School, University of Melbourne
720 Swanston St. Carlton, Victoria 3052
Country 71266 0
Phone 71266 0
+61 03 9341 1547
Fax 71266 0
+61 03 9341 1596
Email 71266 0
Contact person for public queries
Name 71267 0
Prof Eric C. Reynolds
Address 71267 0
Melbourne Dental School, University of Melbourne
720 Swanston St. Carlton, Victoria 3052
Country 71267 0
Phone 71267 0
+61 03 9341 1547
Fax 71267 0
+61 03 9341 1596
Email 71267 0
Contact person for scientific queries
Name 71268 0
Prof Eric C. Reynolds
Address 71268 0
Melbourne Dental School, University of Melbourne
720 Swanston St. Carlton, Victoria 3052
Country 71268 0
Phone 71268 0
+61 03 9341 1547
Fax 71268 0
+61 03 9341 1596
Email 71268 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary