Participants, Interventions And Outcomes
Study setting {9}
Participants will be recruited from a local periodontal clinic. Patients are referred to the specialty clinic by their general dentist or hygienist if they exhibit signs of advanced periodontal disease. Referred patients will be sent an email including the letter of invitation to participate in the study.
Eligibility criteria {10}
Inclusion criteria include patients of both sexes, attending the clinic with diagnosed periodontal disease requiring ST and over the age of 19 who are willing and able to provide informed consent.
Exclusion criteria include pregnancy, breast-feeding, demonstrating glycated hemoglobin (HbA1c) levels greater than 8% in the previous 3 months, chronic GI conditions (e.g. colon cancer, inflammatory bowel disease, celiac disease) and infections, current or previous use of antibiotics for management of non-periodontal conditions within the last 3 months, current use of laxatives, probiotics, prebiotics and/or fibre supplements, and current smoking and/or cannabis use. Patients with severe periodontal disease that require antibiotics with ST as part of their treatment will be withdrawn. This will be determined after the patients initial consultation (visit I). The eligibility criteria are summarized in Table 1.
Table 1. Participant inclusion and exclusion criteria
Inclusion Criteria
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Exclusion Criteria
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Withdrawal Criteria
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· Patients of both sexes attending the clinic with periodontal disease
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· Demonstrating HbA1c levels greater than 8% in the previous 3 months
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· Patients with severe periodontal disease that require antibiotics with ST as part of their treatment
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· Over the age 19 (no upper age restriction)
· Be able to provide informed, written or verbal consent
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· Chronic GI conditions (e.g. colon cancer, inflammatory bowel disease, celiac disease) and infections
· Current or previous use of antibiotics for management of non-periodontal conditions within the past 3 month
· Current use of laxatives, prebiotics, probiotics and/or fibre supplements
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· Smokers and/or cannabis users
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· Pregnant or lactating
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Who will take informed consent? {26a}
Those that are interested in participating in this study will be invited to a virtual meeting with a member of the research team due to the constraints of the COVID-19 pandemic. Participants can either agree to being virtually recorded as the read the statement from the consent form, fill out the consent form and send it back via email or bring the consent form with them to their initial consultation (visit I).
Additional consent provisions for collection and use of participant data and biological specimens {26b}
A proportion of patients continue at the clinic for long-term/indefinite maintenance of their periodontal health. We may perform a follow-up of the participants after one or two years or later from the end of this study if they are continuing to have periodontal maintenance appointments at the clinic. If the participant wishes to be involved with the follow-up study, there is a line on the consent form that they can sign.
Interventions
Explanation for the choice of comparators {6b}
Participants allocated to the study group will receive inulin (10g/day; Orafti®GR, Beneo, Mannheim, Germany) while participants in the placebo group will receive maltodextrin (10 g/day; Canadian Protein; Toronto, Ontario, Canada). Maltodextrin is the most common placebo used in intervention studies with inulin because it has similar physical appearance and energy content to inulin.
Intervention description {11a}
The supplements will be individually packaged in sachets and will contain 10 grams of the specified powder. All participants will be instructed to consume one package per day. Supplements can be mixed with water or with another liquid of choice (250 mL of liquid per serving).
Criteria for discontinuing or modifying allocated interventions {11b}
Inulin administered at 10 g/d is generally well-tolerated, resulting in only mild gastrointestinal (GI) symptoms of gas/bloating, flatulence, constipation, and GI cramping/rumbling [26]. Furthermore, participants will be instructed to divide the 10 g dose into two 5 g doses - in the morning and evening. This method has been shown to have no significant increase in GI symptom incidence [27]. We believe this will minimize, if any, side effects from the intervention. If the participant cannot continue with the study for any reason, they will be aware they may stop the intervention at any time and it will not affect the level of care they receive at the clinic.
Strategies to improve adherence to interventions {11c}
All participants will receive exactly 100 sachets to last them until their scheduled follow-up appointment. They will be asked to return any unused sachets when they come in for their follow-up to account for missed dosages. Participants will receive a daily reminder to take the prebiotic in the morning and afternoon using an online application (Auto Message) and will also be instructed to take it prior to brushing their teeth in the morning and at night as an additional reminder.
Relevant concomitant care permitted or prohibited during the trial {11d}
All relevant concomitant care will be permitted and recorded.
Provisions for post-trial care {30}
There will be no post trial care. It is anticipated that there will be no risks requiring compensation.
Outcomes {12}
Primary outcome measures
- Clinical Assessment
- Number of sites with PD ≥ 4 mm
- Absence of BOP
Secondary outcome measures
- Salivary Markers of Inflammation
- Interleukin-1ß (IL-1ß)
- IL-6
- CRP
- Matrix Metalloproteinase-8 (MMP-8)
- Periodontal-Associated Pathogens
- Aggregatibacter actinomycetemcomitans
- Porphyromonas gingivalis
- Tannerella forsythia
- Treponema denticola
- Anthropometric Parameters
- Body weight (kg)
- Height (m)
- Dietary Assessment
- Energy Intake
- Carbohydrate Intake
- Fat Intake
- Protein Intake
Periodontal Examination
All periodontal examinations will be completed by Registered Dental Hygienists with 15 years or more of experience using a periodontal probe. Multiple hygienists will participate in this study and to ensure consistency among measurements, they will be calibrated to apply 25 N of pressure by using electronic scale [28]. Six PD sites will be measured on all teeth and implants (mesiobuccal, buccal, distobuccal, mesiolingual, lingual and distolingual) as previously described [28]. The total number of sites with probing depths ≥ 4 mm will be measured. BOP will be measured by visual inspection and expressed as either absent or present at each of the sites.
Saliva Collection and Measurement of Markers of Inflammation
Participants will rinse with 85 mL of water for approximately 1 minute, 10 minutes prior to collection. Saliva will be collected using unstimulated passive drool and a saliva collection aid (Salimetrics; Carlsbad, CA) into a prelabeled collection vial. Saliva samples will be stored on ice in a small cooler, centrifuged at 3000 g for 15 minutes and supernatant collected into a labeled sterile tube and stored at -80°C until analysis. IL-1ß, IL-6 and CRP will be analyzed using enzyme‐linked immunosorbent assay kits (Salimetrics; Carlsbad, CA) and MMP-8 will be analyzed using a human quantikine enzyme‐linked immunosorbent assay kits (R&D Systems, Inc.; Oakville, Canada) as per the manufacturer’s instructions. All assays will be completed in triplicate.
Periodontal-Associated Pathogens
Participants will rinse with saline for 30 seconds then expectorate spit in a collection tube. This sample will be taken after the saliva sample that will be used for measurement of markers of inflammation. Samples will be frozen at -80°C until further analysis. A. actinomycetemcomitans, P. gingivalis, T. forsythia and T. denticola will be quantified by quantitative PCR [29].
Dietary Assessment
Dietary intakes will be measured using the Canadian version of the Automated Self-Administered 24-hour (ASA24®) Dietary Assessment Tool. The ASA24 will be completed online by participants and food intakes will be recalled over a 24-hour period. ASA24 features two web-based applications, one that the participant will use to complete dietary recalls and one for the researcher to access nutrient analyses. Participants will be asked to complete 3 dietary assessments at each visit time point (two weekdays and one weekend day) to obtain an accurate representation. Participants will be given their username and password for the ASA24 respondent website so that they can complete the dietary assessments at home. The username will match their unique code administered on the intervention package. Participants will complete the first set of recalls before they begin the intervention. For visits II, and III, the research team will email or call the participant a week before their upcoming appointment and instruct them to log on to the ASA24 website and complete a set of food recalls before they return to the clinic for their next visit. Total energy intake, protein, fat and carbohydrate intakes will be extrapolated from the assessments for the analysis. The means of each nutrient will be taken from the 3 recalls for each visit.
Anthropometric Assessment
Height and weight will be measured to calculate BMI (kg/m2). Participants will be asked to remove their shoes and will be weighed and height will be measured to the nearest 0.1 kg and 0.1 m, respectively, using a height and weight scale (Health-O-Meter Professional; Sunbeam Products, Inc.). If certain situations prevent height and weight from being taken (COVID-19 pandemic), we will use self-reported height and weight.
Participant timeline {13}
Table 2. Schedule for enrollment, intervention, and assessments during the study period.
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STUDY PERIOD
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Enrolment
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Allocation
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Post-allocation
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TIMEPOINT
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Visit 0
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Visit I
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4 weeks pre-ST
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Visit II
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Visit III (10 weeks post-ST)
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RECRUITMENT:
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Eligibility screen
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X
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Informed consent
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X
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Allocation
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X
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Randomization (I or C)
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X
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INTERVENTIONS:
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Inulin
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X
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X
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Control
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X
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X
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X
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ASSESSMENTS:
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Clinical Assessment (PD)
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X
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X
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Salivary Markers of Inflammation
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X
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X
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X
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Periodontal-Associated Pathogens
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X
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X
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X
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ASA24
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XXX
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XXX
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XXX
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BMI
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X
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X
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X
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Sample size {14}
Sample Size for Pilot Study
No randomized controlled trials have investigated the combined effect of inulin with ST on periodontal outcomes. To ensure the feasibility of the study – including participant adherence to the protocol and sample collection - a pilot study will be performed. The goal is to obtain data from 20 participants for each group during the pilot study. Assuming that up to 20% of participants may drop-out or be withdrawn; we will aim to recruit 24 participants per group, for a total of 48 participants. If no unforeseen difficulties arise in the pilot study, participant data will be part of the full trial.
Sample Size for Full Trial
The number of sites with probing depths ≥ 4 mm was used to determine sample size, as ST has been shown to reduce BOP to minimal levels to the point where an adjunct could not increase the effectiveness [3]. Previous literature has reported the mean change in number of sites with probing depths ≥ 4 mm from baseline to an average follow-up of 10.86 weeks is a mean of 81 with a standard deviation of 21 [3]. It has been shown that a high fibre diet can result in a 4% decrease in average PD though these participants were not diagnosed with periodontal disease and were not undergoing treatment with ST [24]. We believe it is reasonable to estimate that participants who are suffering from this disease and have deeper probing depths will experience a greater reduction in PD ≥ 4 mm in combination with ST (10%), as baseline PD is positively associated with follow-up PD [3]. Thus, the estimated mean change in the number of sites with probing depths ≥ 4 mm is 91. Using a power of 80% and an alpha of 0.05, the total number of participants needed per group is 71. A 20% drop-out rate is estimated; the sample size for the full trial is 85 per group, or a total 170 participants. The sample size needed for the full trial was estimated using a statistical software (G*Power 3.1).
Recruitment {15}
The clinic typically sees 200 patients per year for ST with 65% of the patients being nonsmokers, leaving a total of 130 patients who are eligible to participate in the study. Of those 130 individuals, 10% of people will have severe cases of periodontal disease that will require antibiotics with ST. This equates to 117 patients per year that remain eligible to participate in the study. We are estimating that 60% of people will agree to participate on the study, given the time commitment to the intervention. Previous data we collected showed 64.7% of patients undergoing periodontal surgery reported using one or more dietary supplements [25]. We anticipate that the same proportion of patients undergoing ST will be highly motivated to further support their recovery and will agree to the study. Therefore, the recruitment for 48 participants in the pilot study will be completed within one year. It is expected that participants from the pilot study will be included as part of the full trial sample size.
Assignment of interventions: allocation
Sequence generation {16a}
A computer-generated list of random numbers will be used to create a sequential set of unique codes with an equal number of participants assigned to each of the two groups.
Concealment mechanism {16b}
A member of the research team will be responsible for the randomization and labeling of the packages. Each intervention package will contain 100 sachets of the either the control or intervention product. The packages will be labelled with the unique codes that were generated. There will be a master list, kept in a locked office at the clinic, which matches the unique code with the corresponding treatment.
Implementation {16c}
At the clinic, the participants will receive a random intervention package with the corresponding unique code from a member of the research team. This will become the unique code that identifies the participant. Participants will be instructed to use this code to complete their dietary assessments at home. This code will also be used to label saliva samples.
Assignment of interventions: Blinding
Who will be blinded {17a}
The trial participants and care providers will be blinded to the group allocation.
Procedure for unblinding if needed {17b}
In the case of emergency and a participants’ allocated intervention needs to be revealed, a staff member at the clinic will match the master list to the list that identifies the participants name and code.
Data collection and management
Plans for assessment and collection of outcomes {18a}
Clinical data, including periodontal outcomes and anthropometric measurements, will be collected from electronic patient files and recorded in a specialized spreadsheet. This will be combined with data from the online dietary assessments and saliva analyses.
Plans to promote participant retention and complete follow-up {18b}
Participants regularly attend the appointments where we will be collecting data for their clinical care. Thus, we have designed the intervention around this schedule. As previously mentioned, side effects will be minimized by taking the intervention as two separate doses during the day. Also, we have minimized the burden on the participants by having the treatments individually packaged.
Data management {19}
Dietary Questionnaires will be filled out online and will be downloaded from the ASA24 website onto a spreadsheet file that will become the main data set. Data from the clinic and saliva analyses will be added to said file upon completion and a second member of the research team will go through the imputed information to check for any errors. Regular back-ups will be made in the study folder on the protected research server/computers to prevent loss of data. Verbally recorded informed consent will be recorded in the electronic participant folder and signed paper forms will be stored at the clinic.
Confidentiality {27}
The participant’s name and their unique code will be recorded on a separate list that will be stored in a separate location from the master list at the clinic. Once the study is completed, the list that contains the participant’s name and which unique code they received will be combined with the master list, along with clinic data including probing depth and anthropometric measurements. In order to maintain participant confidentiality, only the participant’s unique code and their corresponding data will be exported from the clinic to conduct the analyses. Saliva samples will be labelled with the participant’s unique code and the researcher conducting the analysis will not know whom they belong to. Dietary questionnaires will also be completed using the unique code.
Plans for collection, laboratory evaluation and storage of biological specimens for genetic or molecular analysis in this trial/future use {33}
Saliva samples will be stored at Brock University and any remaining sample will be destroyed after 10 years.
Statistical methods
Statistical methods for primary and secondary outcomes {20a}
Data will be entered into excel by a member of the research team. Another member will double check the numbers and values to ensure accuracy of data entry. Statistical analyses will be performed using IBM SPSS 26 statistical software and significance will be determined when P < 0.05. Mean and standard deviations will be reported for outcomes. Analysis of baseline participant demographics will be calculated to ensure consistency between the groups. The Kolmogorov-Smirnov test will be used to test the normality of the data. The Levene’s test will be used to assess the equality of variances. Probing depths outcomes will be analyzed using an independent sample t test for the mean change in number of PD ≥ 4 mm. If the data is not normally distributed, a Mann-Whitney test will be used. BOP is a categorical variable and chi‐square analyses will be performed to measure the associations between the absence of bleeding and the treatment group.
The concentrations of the four salivary biomarkers and the quantitative values of the four periodontal pathogens at all three sample collection times will be log transformed to normalize their distribution. Two-way repeated measures analysis of variance (ANOVA) using treatment x time will be used to analyze each biomarker and pathogen individually. A repeated-measures ANOVA with Tukey’s post hoc test will be used to determine to determine changes in energy and macronutrient intakes over the 3 visits in the intervention and control groups.
Interim analyses {21b}
There are no interim analyses planned.
Methods for additional analyses (e.g. subgroup analyses) {20b}
The study will also determine if there is a difference in the effect of inulin on the primary outcomes in terms of BMI. Subgroup analyses for the number of sites with PD ≥ 4 mm will be performed using two categories for BMI: normal BMI (˂25 kg/m2) or overweight/obese (≥ 25 kg/m2). This analysis will be conducted using an independent sample t test. Chi‐square analyses will be performed for BOP.
Methods in analysis to handle protocol non-adherence and any statistical methods to handle missing data {20c}
We want to ensure the treatment effect is not conservative; therefore a modified-to-treat approach will be used in the analysis of this trial. To be included in the analysis, participants will need to take the intervention for 75% of the 28 days pre-ST and for 75% of the 70 days post-ST. The study protocol is designed to maximize data collection. Missing data for secondary outcomes, particularly dietary intakes, the statistical method of multiple imputation will be used.
Plans to give access to the full protocol, participant level-data and statistical code {31c}
This study presents the full protocol. The datasets can be made available by the corresponding author when the trial concludes.
Oversight and monitoring
Composition of the coordinating centre and trial steering committee {5d}
N/A – This is a single clinic trial involving a nutritional supplement.
Composition of the data monitoring committee, its role and reporting structure {21a}
N/A - There are no anticipated risks associated with the nutritional supplement intervention.
Adverse event reporting and harms {22}
Hypersensitivity to inulin is extremely rare and mostly benign. We do not expect any adverse events to occur and participants can stop taking the intervention at any time.
Frequency and plans for auditing trial conduct {23}
N/A – The trial will not be audited.
Plans for communicating important protocol amendments to relevant parties (e.g. trial participants, ethical committees) {25}
Protocol amendments will be first approved by the Research Ethics Board at Brock University. The online trial registry will then be updated accordingly. Participants will be notified by phone or email.
Dissemination plans {31a}
We will disseminate the study findings through peer-reviewed journal publications and conference presentations. Once the manuscript has been accepted for publication, a lay summary of the study will be sent to all participants. This lay summary will include a brief statement of why the study was conducted and the aim, the salient findings, and the importance of the study including a take home message of what the study has shown.