Efficacy of Manual Toothbrushes in Removing Dental Plaque

Dental Plaque Clinical Trial

Official title:

Randomized Controlled Examiner-Blind Methodology Development Study To Investigate The Plaque Removal Efficacy Of Manual Toothbrushes In Healthy Dentate Subjects

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT04025684
• Other study ID #: 212224
• Status: Completed
• Phase: N/A
• Start date: September 30, 2019
• Est. completion date: December 10, 2019

Study information

• Verified date: January 2021
• Source: GlaxoSmithKline
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

This clinical methodology development study will evaluate the plaque removal efficacy of four marketed manual toothbrushes, with differing bristle types and brush head designs, in healthy dentate participants. Changes in supra-gingival plaque accumulation will be assessed after first use and following 1-and 4-weeks treatment (twice-daily brushing), using two different clinical measures of dental plaque. Study participants will abstain from oral hygiene for a period of 12-18 hours prior to each assessment visit. Data generated will inform the design of future clinical studies investigating the plaque removal efficacy of manual toothbrushes.

Description:

This will be a single center, 4-week, randomized, controlled, examiner-blind, four-treatment arm, parallel design, clinical methodology development study to investigate the plaque removal efficacy of marketed manual toothbrushes in healthy, dentate participants. Changes in plaque level will be evaluated after first brushing, after two further single brushing events (Days 7 and 28) and following 7 and 28 days usage (twice daily brushing with assigned toothbrush treatment).

Supra-gingival plaque levels will be assessed using two established clinical measures: the Rustogi Modified Navy Plaque Index (RPI) and the 6-site Turesky Modified Quigley and Hein Plaque Index (TPI). Participants will abstain from oral hygiene for a period of 12-18 hours prior to each assessment visit. Participants with Day 0 pre-brushing mean RPI overall ≥ 0.6 will be stratified by their Day 0 pre-brushing RPI score (lower: mean RPI overall ≥ 0.6 to ≤ 0.8; higher: mean RPI overall; 0.8 to 1.0) and randomized to study treatment (Visit 2).

To standardize oral hygiene practice, eligible participants will complete a lead-in period (minimum 5 days) prior to Visit 2 during which they will brush with the toothbrush and regular fluoride toothpaste provided.

The safety and oral tolerability of each study toothbrush will be monitored after first use and over the 28-day usage period by review of reported treatment emergent adverse events (TEAEs).

Recruitment information / eligibility

• Status: Completed
• Enrollment: 80
• Est. completion date: December 10, 2019
• Est. primary completion date: December 10, 2019
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 65 Years

Eligibility

Inclusion Criteria:

An individual must meet all the following inclusion criteria to be eligible for enrollment into the study.

• Participant provision of a signed and dated informed consent document indicating that the participant has been informed of all pertinent aspects of the study before any assessment is performed.

• A participant who is willing and able to comply with scheduled visits, treatment plan and other study procedures.

• A participant in good general, mental and oral health with, in the opinion of the investigator or medically qualified designee, no clinically significant or relevant abnormalities in medical history or upon oral examination, or condition, that would impact the participant's safety, well-being or the outcome of the study, if they were to participate in the study, or affect the individual's ability to understand and follow study procedures and requirements.

• A participant with, in the opinion of the investigator or medically qualified designee, satisfactory oral hygiene based on oral examination.

• A participant who routinely uses a manual toothbrush for daily oral hygiene.

• VISIT 1 (Screening): A participant must have a) = 20 natural, permanent teeth b) = 40 gradable tooth surfaces (= 2/3rds of the tooth surface assessable for RPI).Third molars, fully crowned/ extensively restored, grossly carious, orthodontically-banded/bonded or abutment teeth and surfaces with calculus deposits which, in the opinion of the clinical examiner, would interfere with plaque assessment should not be included in the gradable surface count. Third molars can be included if, as a result tooth loss, they are functioning as second molars.

• VISIT 2 (Baseline): A participant must have a pre-brushing mean RPI = 0.6 overall (that is, the mean over all gradable surfaces)

Exclusion Criteria:

An individual who meets any of the following exclusion criteria will not be eligible for enrollment into the study.

• A participant who is an employee of the investigational site, either directly involved in the conduct of the study or otherwise supervised by the investigator, or a member of their immediate family; or a GSK CH employee directly involved in the conduct of the study or a member of their immediate family.

• A participant who has participated in other studies (including non-medicinal studies) involving investigational product(s) in the 30 days prior to study entry and/or who is participating in other studies during study participation.

• A participant with, in the opinion of the investigator or medically qualified designee, an acute or chronic medical or psychiatric condition or laboratory abnormality that may increase the risk associated with study participation or investigational product administration or may interfere with the interpretation of study results and, in the judgment of the investigator or medically qualified designee, would make the participant inappropriate for entry into this study.

• A participant with any medical/oral condition which, in the opinion of the investigator or medically qualified designee, could impact study outcomes (for example, oral dryness).

• A participant taking daily doses of medication/having daily treatments which, in the opinion of the investigator or medically qualified designee, could impact study outcomes (for example, is causing oral dryness).

• A participant with any condition or physical limitation which, in the opinion of the investigator or medically qualified designee, impacts their ability to perform oral hygiene with a manual toothbrush.

• A participant who is pregnant (self-reported; no pregnancy test required) or intending to become pregnant over the course of the study.

• A participant who is breastfeeding.

• A participant with known or suspected intolerance or hypersensitivity to the study materials (or closely related compounds) or any of their stated ingredients.

• A participant who is unwilling or unable to comply with the following Lifestyle Considerations described in this protocol: 1) Dental Product/Treatment and Oral Hygiene Restrictions i)From Screening (Visit 1) to the Participant's Last Study Visit: a) Participants should not use any other oral care products (for example, toothpastes, toothbrushes, oral rinses, tongue cleaners, whitening/bleaching products, inter-dental cleaning products)than those provided during the study. Note: dental floss (non-antibacterial) can be used to remove impacted food; b) Participants should not chew gum or consume any confectionery containing xylitol (e.g. sugar-free mints); c) Participants should delay any non-emergency dental treatment until after study completion (including dental prophylaxis); d)Participants should delay any tooth whitening treatments (professional and/or home use) until after study completion; ii) Before Clinical Efficacy Assessment Visits (Visits 2-4): Participants should refrain from oral hygiene procedures for 12-18 hours before their visit; 2) Meals and Dietary Restrictions i) Before Clinical Efficacy Assessment Visits (Visits 2-4): Participants should not eat or drink for = 1 hour before their visit and until all visit procedures have been completed.

• A participant who has had routine dental prophylaxis within 4 weeks of Screening.

• A participant who has undergone a tooth bleaching procedure within 8 weeks of Screening.

• A participant with, in the opinion of the investigator or medically qualified designee, generalized moderate/severe gingivitis.

• A participant with, in the opinion of the investigator or medically qualified designee, gross periodontal disease.

• A participant with, in the opinion of the investigator or medically qualified designee, signs of active periodontitis.

• A participant with a Basic Periodontal Examination (BPE) score = 3 in any sextant.

• A participant who has undergone treatment for periodontal disease within 12 months of Screening, including scaling and/or root surface debridement.

• A participant who is currently undergoing treatment for periodontal disease, including scaling and/or root surface debridement.

• A participant with active caries which, in the opinion of the investigator or medically qualified designee, could impact study outcomes or the oral health of the participant if they were to participate in the study.

• A participant with, in the opinion of the investigator or medically qualified designee, evidence of gross intra-oral neglect or the need for extensive dental therapy.

• A participant with restorations in a poor state of repair which, in the opinion of the investigator or medically qualified designee, could impact study outcomes.

• A participant with any dental condition (e.g. malalignment, overcrowding) which, in the opinion of the investigator or medically qualified designee, could impact study outcomes.

• A participant with high levels of extrinsic dental stain or calculus deposits which, in the opinion of the investigator or medically qualified designee, would interfere with plaque assessment or impact study outcomes.

• A participant with a tongue or lip piercing.

• A participant with multiple dental implants which, in the opinion of the investigator or medically qualified designee, could impact study outcomes.

• A participant with fixed bridge(s) or removable partial dentures.

• A participant with fixed or removable orthodontic braces/bands or a fixed orthodontic retainer.

• A participant who has had fixed or removable orthodontic braces/bands within 3 months of Screening.

• A participant who is unwilling to forgo use of an orthodontic retainer for the duration of the study, provided there would be no impact on the outcome of any previous, completed orthodontic treatment or the participant's well-being.

• VISIT 1 (Screening): A participant who has taken antibiotics within 2 weeks of Screening.

• VISIT 2 (Baseline): A participant who has taken antibiotics during the lead-in period (between Screening and Visit 2).

• Participant with a recent history (within the last year) of alcohol or other substance abuse.

• A participant who, in the opinion of the investigator or medically qualified designee, should not participate in the study.

• A participant who has previously been enrolled in this study.

Related Conditions & MeSH terms

• Dental Plaque
• Oral Hygiene

Intervention

Other:
• Oral B Indicator 123
Manual toothbrush (medium bristle stiffness; compact head, UK market).
• Dr Best Original
Manual toothbrush (medium bristle stiffness; regular head, German market)
• Dr Best Multi Expert
Manual toothbrush (medium bristle stiffness; compact head, German market)
• parodontax Interdental
Manual toothbrush (soft bristle stiffness; compact head, German market)

Locations

Country	Name	City	State
United Kingdom	GSK Investigational Site	Birmingham	West Midlands

Sponsors (1)

Lead Sponsor	Collaborator
GlaxoSmithKline

Country where clinical trial is conducted

United Kingdom, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Change From Pre to Post Brushing in Overall Mean Rustogi Modified Navy Plaque Index (RPI) After a Single Brushing Event at Day 0	Supra-gingival plaque was assessed on the facial and lingual surfaces of the teeth (7-7 each arch) using RPI. Each tooth surface was divided into 9 zones, for a total of 18 sites per tooth (A to I facial with 9 sites and lingual with 9 sites separately); A to C along gingival margin; D to F directly above A to C (D and F being inter-proximal zones); G to H across middle of tooth; and I covered incisal area. Plaque was disclosed and presence or absence of plaque in each zone was recorded as per scoring criteria: 0-Plaque absent, 1-Plaque present; where lower score represents better result. An average score for a participant was generated by averaging across all sites and surfaces of all teeth assessed. Change from pre-brushing = (post-brushing score - pre-brushing score). Overall mean calculated for all participants was reported.	At Day 0
Primary	Change From Pre to Post Brushing in Overall Mean Turesky Modified Quigley & Hein Plaque Index (TPI) After a Single Brushing Event at Day 0	Supra-gingival plaque accumulation was assessed on facial and lingual surfaces of teeth (7-7 in each arch) using TPI. Plaque was assessed with each tooth being divided into 6 areas including mesiofacial, facial, distofacial, mesiolingual, lingual and distolingual surfaces and scored for each site on a scale of 0 to 5: 0-No plaque, 1-Slight flecks of plaque at cervical margin of tooth, 2-Thin, continuous band of plaque (1millimetre [mm] or smaller) at cervical margin of tooth, 3-Band of plaque wider than 1mm but covering less than 1/3 of area, 4-Plaque covering at least 1/3 but less than 2/3 of area, 5-Plaque covering 2/3 or more of crown of tooth; where lower score represents better result. An average score for a participant was generated by averaging across all sites and surfaces of all teeth assessed. Change from pre-brushing = (post-brushing score - pre-brushing score). Overall mean calculated for all participants was reported.	At Day 0
Secondary	Change From Baseline (Day 0 Pre-Brushing) to Post-Brushing in Overall Mean Rustogi Modified Navy Plaque Index (RPI) at Day 7 and Day 28	Supra-gingival plaque was assessed on the facial and lingual surfaces of the teeth (7-7 each arch) using RPI. Each tooth surface was divided into 9 zones, for a total of 18 sites per tooth (A to I facial with 9 sites and lingual with 9 sites separately); A to C along gingival margin; D to F directly above A to C (D and F being inter-proximal zones); G to H across middle of tooth; and I covered incisal area. Plaque was disclosed and presence or absence of plaque in each zone was recorded as per scoring criteria: 0-Plaque absent, 1-Plaque present; where lower score represents better result. An average score for a participant was generated by averaging across all sites and surfaces of all teeth assessed. Change from Day 0 pre-brushing at Day 7/28 = (post-brushing score at Day 7/28- pre-brushing score at Day 0). Overall mean calculated for all participants was reported.	At Day 0, Day 7 and Day 28
Secondary	Change From Baseline (Day 0 Pre-Brushing) to Post-Brushing in Overall Mean Turesky Modified Quigley & Hein Plaque Index (TPI) at Day 7 and Day 28	Supra-gingival plaque accumulation was assessed on facial and lingual surfaces of teeth (7-7 in each arch) using TPI. Plaque was assessed with each tooth being divided into 6 areas including mesiofacial, facial, distofacial, mesiolingual, lingual and distolingual surfaces and scored for each site on a scale of 0 to 5: 0-No plaque, 1-Slight flecks of plaque at cervical margin of tooth, 2-Thin, continuous band of plaque (1mm or smaller) at cervical margin of tooth, 3-Band of plaque wider than 1mm but covering less than 1/3 of area, 4-Plaque covering at least 1/3 but less than 2/3 of area, 5-Plaque covering 2/3 or more of crown of tooth; where lower score represents better result. An average score for a participant was generated by averaging across all sites and surfaces of all teeth assessed. Change from Day 0 pre-brushing at Day 7/28 = (post-brushing score at Day 7/28- pre-brushing score at Day 0). Overall mean calculated for all participants was reported.	At Day 0, Day 7 and Day 28
Secondary	Overall Mean Rustogi Modified Navy Plaque Index (RPI) Pre- and Post-brushing at Day 7 and Day 28	Supra-gingival plaque was assessed on the facial and lingual surfaces of the teeth (7-7 each arch) using RPI. Each tooth surface was divided into 9 zones, for a total of 18 sites per tooth (A to I facial with 9 sites and lingual with 9 sites separately); A to C along gingival margin; D to F directly above A to C (D and F being inter-proximal zones); G to H across middle of tooth; and I covered incisal area. Plaque was disclosed and presence or absence of plaque in each zone was recorded as per scoring criteria: 0-Plaque absent, 1-Plaque present; where lower score represents better result. An average score for a participant was generated by averaging across all sites and surfaces of all teeth assessed. Overall mean calculated for all participants was reported.	At Day 7 and Day 28
Secondary	Overall Mean Turesky Modified Quigley & Hein Plaque Index (TPI) Pre- and Post-brushing TPI at Day 7, and Day 28	Supra-gingival plaque accumulation was assessed on facial and lingual surfaces of teeth (7-7 in each arch) using TPI. Plaque was assessed with each tooth being divided into 6 areas including mesiofacial, facial, distofacial, mesiolingual, lingual and distolingual surfaces and scored for each site on a scale of 0 to 5: 0-No plaque, 1-Slight flecks of plaque at cervical margin of tooth, 2-Thin, continuous band of plaque (1mm or smaller) at cervical margin of tooth, 3-Band of plaque wider than 1mm but covering less than 1/3 of area, 4-Plaque covering at least 1/3 but less than 2/3 of area, 5-Plaque covering 2/3 or more of crown of tooth; where lower score represents better result. An average score for a participant was generated by averaging across all sites and surfaces of all teeth assessed. Overall mean calculated for all participants was reported.	At Day 7 and Day 28
Secondary	Change From Baseline (Day 0 Pre-Brushing) to Post-Brushing in Gingival Margin Sites Mean Rustogi Modified Navy Plaque Index (RPI) at Day 0, Day 7 and Day 28	Supra-gingival plaque accumulation was assessed for gingival zone A to C. Plaque was disclosed and presence or absence of plaque in each zone was recorded as per scoring criteria: 0-Plaque absent, 1-Plaque present; where lower score represents better result. An average score for a participant was generated by averaging across all sites and surfaces of all teeth assessed. Change from Day 0 pre-brushing at Day 0/7/28= (post-brushing score at Day 0/7/28- pre-brushing score at Day 0). Mean calculated for all participants was reported.	At Day 0, Day 7 and Day 28
Secondary	Change From Baseline (Day 0 Pre-Brushing) to Post-Brushing in Inter-Proximal Sites Mean Rustogi Modified Navy Plaque Index (RPI) at Day 0, Day 7 and Day 28	Supra-gingival plaque accumulation was assessed for inter-proximal zones D to F. Plaque was disclosed and presence or absence of plaque in each zone was recorded as per scoring criteria: 0-Plaque absent, 1-Plaque present; where lower score represents better result. An average score for a participant was generated by averaging across all sites and surfaces of all teeth assessed. Change from Day 0 pre-brushing at Day 0/7/28= (post-brushing score at Day 0/7/28- pre-brushing score at Day 0). Mean calculated for all participants was reported.	At Day 0, Day 7 and Day 28
Secondary	Change From Baseline (Day 0 Pre-Brushing) to Post-Brushing in Inter-Proximal Sites Mean Turesky Modified Quigley & Hein Plaque Index (TPI) at Day 0, Day 7 and Day 28	Supra-gingival plaque accumulation was assessed for inter-proximal zones D to F. Plaque was disclosed and scored for each site on a scale of 0 to 5: 0-No plaque, 1-Slight flecks of plaque at cervical margin of tooth, 2-Thin, continuous band of plaque (1mm or smaller) at cervical margin of tooth, 3-Band of plaque wider than 1mm but covering less than 1/3 of area, 4-Plaque covering at least 1/3 but less than 2/3 of area, 5-Plaque covering 2/3 or more of crown of tooth; where lower score represents better result. An average score for a participant was generated by averaging across all sites and surfaces of all teeth assessed. Change from Day 0 pre-brushing at Day 0/7/28= (post-brushing score at Day 0/7/28- pre-brushing score at Day 0). Mean calculated for all participants was reported.	At Day 0, Day 7 and Day 28
Secondary	Gingival Margin Sites Mean Rustogi Modified Navy Plaque Index (RPI) Pre- and Post-brushing at Day 0, Day 7 and Day 28	Supra-gingival plaque accumulation was assessed for gingival zone A to C. Plaque was disclosed and presence or absence of plaque in each zone was recorded as per scoring criteria: 0-Plaque absent, 1-Plaque present; where lower score represents better result. An average score for a participant was generated by averaging across all sites and surfaces of all teeth assessed. Mean calculated for all participants was reported.	At Day 0, Day 7 and Day 28
Secondary	Inter-Proximal Sites Mean Rustogi Modified Navy Plaque Index (RPI) Pre- and Post-brushing at Day 0, Day 7 and Day 28	Supra-gingival plaque accumulation was assessed for inter-proximal zones D to F. Plaque was disclosed and presence or absence of plaque in each zone was recorded as per scoring criteria: 0-Plaque absent, 1-Plaque present; where lower score represents better result. An average score for a participant was generated by averaging across all sites and surfaces of all teeth assessed. Mean calculated for all participants was reported.	At Day 0, Day 7 and Day 28
Secondary	Inter-Proximal Sites Mean Turesky Modified Quigley & Hein Plaque Index (TPI) Pre- and Post-brushing TPI at Day 0, Day 7 and Day 28	Supra-gingival plaque accumulation was assessed for inter-proximal zones D to F. Plaque was disclosed and scored for each site on a scale of 0 to 5: 0-No plaque, 1-Slight flecks of plaque at cervical margin of tooth, 2-Thin, continuous band of plaque (1mm or smaller) at cervical margin of tooth, 3-Band of plaque wider than 1mm but covering less than 1/3 of area, 4-Plaque covering at least 1/3 but less than 2/3 of area, 5-Plaque covering 2/3 or more of crown of tooth; where lower score represents better result. An average score for a participant was generated by averaging across all sites and surfaces of all teeth assessed. Mean calculated for all participants was reported.	At Day 0, Day 7 and Day 28
Secondary	Change From Baseline (Day 0 Pre-Brushing) in Overall Rustogi Modified Navy Plaque Index (RPI) at Day 7 Pre-brushing and Day 28 Pre-brushing	Supra-gingival plaque was assessed on the facial and lingual surfaces of the teeth (7-7 each arch) using RPI. Each tooth surface was divided into 9 zones, for a total of 18 sites per tooth (A to I facial with 9 sites and lingual with 9 sites separately); A to C along gingival margin; D to F directly above A to C (D and F being inter-proximal zones); G to H across middle of tooth; and I covered incisal area. Plaque was disclosed and presence or absence of plaque in each zone was recorded as per scoring criteria: 0-Plaque absent, 1-Plaque present; where lower score represents better result. An average score for a participant was generated by averaging across all sites and surfaces of all teeth assessed. Change from Day 0 pre-brushing at Day 7/28= (pre-brushing score at Day 7/28- pre-brushing score at Day 0). Overall mean calculated for all participants was reported.	At Day 0, Day 7 pre-brushing and Day 28 pre-brushing
Secondary	Change From Baseline (Day 0 Pre-Brushing) in Overall Mean Turesky Modified Quigley & Hein Plaque Index (TPI) at Day 7 Pre-brushing and Day 28 Pre-brushing	Supra-gingival plaque accumulation was assessed on facial and lingual surfaces of teeth (7-7 in each arch) using TPI. Plaque was assessed with each tooth being divided into 6 areas including mesiofacial, facial, distofacial, mesiolingual, lingual and distolingual surfaces and scored for each site on a scale of 0 to 5: 0-No plaque, 1-Slight flecks of plaque at cervical margin of tooth, 2-Thin, continuous band of plaque (1mm or smaller) at cervical margin of tooth, 3-Band of plaque wider than 1mm but covering less than 1/3 of area, 4-Plaque covering at least 1/3 but less than 2/3 of area, 5-Plaque covering 2/3 or more of crown of tooth; where lower score represents better result. An average score for a participant was generated by averaging across all sites and surfaces of all teeth assessed. Change from Day 0 pre-brushing at Day 7/28= (pre-brushing score at Day 7/28- pre-brushing score at Day 0). Overall mean calculated for all participants was reported.	At Day 0, Day 7 pre-brushing and Day 28 pre-brushing
Secondary	Change From Baseline (Day 0 Pre-Brushing) in Gingival Margin Sites Mean Rustogi Modified Navy Plaque Index (RPI) at Day 7 Pre-brushing and Day 28 Pre-brushing	Supra-gingival plaque accumulation was assessed for gingival zone A to C. Plaque was disclosed and presence or absence of plaque in each zone was recorded as per scoring criteria: 0-Plaque absent, 1-Plaque present; where lower score represents better result. An average score for a participant was generated by averaging across all sites and surfaces of all teeth assessed. Change from Day 0 pre-brushing at Day 7/28= (pre-brushing score at Day 7/28- pre-brushing score at Day 0). Mean calculated for all participants was reported.	At Day 0, Day 7 pre-brushing and Day 28 pre-brushing
Secondary	Change From Baseline (Day 0 Pre-Brushing) in Inter-Proximal Sites Mean Rustogi Modified Navy Plaque Index (RPI) at Day 7 Pre-brushing and Day 28 Pre-brushing	Supra-gingival plaque accumulation was assessed for inter-proximal zones D to F. Plaque was disclosed and presence or absence of plaque in each zone was recorded as per scoring criteria: 0-Plaque absent, 1-Plaque present; where lower score represents better result. An average score for a participant was generated by averaging across all sites and surfaces of all teeth assessed. Change from Day 0 pre-brushing at Day 7/28= (pre-brushing score at Day 7/28- pre-brushing score at Day 0). Mean calculated for all participants was reported.	At Day 0, Day 7 pre-brushing and Day 28 pre-brushing
Secondary	Change From Baseline (Day 0 Pre-Brushing) in Inter-Proximal Sites Mean Turesky Modified Quigley & Hein Plaque Index (TPI) at Day 7 Pre-brushing and Day 28 Pre-brushing	Supra-gingival plaque accumulation was assessed for inter-proximal zones D to F. Plaque was disclosed and scored for each site on a scale of 0 to 5: 0-No plaque, 1-Slight flecks of plaque at cervical margin of tooth, 2-Thin, continuous band of plaque (1mm or smaller) at cervical margin of tooth, 3-Band of plaque wider than 1mm but covering less than 1/3 of area, 4-Plaque covering at least 1/3 but less than 2/3 of area, 5-Plaque covering 2/3 or more of crown of tooth; where lower score represents better result. An average score for a participant was generated by averaging across all sites and surfaces of all teeth assessed. Change from Day 0 pre-brushing at Day 7/28= (pre-brushing score at Day 7/28- pre-brushing score at Day 0). Mean calculated for all participants was reported.	At Day 0, Day 7 pre-brushing and Day 28 pre-brushing