Guided Biofilm Therapy Versus Conventional Polishing for Tooth Re-Staining

This randomized split-mouth clinical trial was conducted in adults with visible extrinsic tooth staining. The aim was to compare Guided Biofilm Therapy (GBT) with conventional polishing in terms of post-procedural extrinsic tooth re-staining, patient discomfort, and procedure time.

Each participant received both interventions. One side of the mouth was assigned to GBT and the contralateral side to conventional polishing. The right-left allocation of the interventions was determined by randomization, with the two allocation sequences equally distributed among participants.

In the GBT intervention, dental biofilm was first disclosed and then removed using an air-water-powder system with a low-abrasive erythritol-based powder. Supragingival ultrasonic instrumentation was performed where necessary. In the conventional polishing intervention, supragingival instrumentation was followed by mechanical polishing with a brush and polishing paste.

Tooth color was assessed using a SpectroShade Micro spectrophotometer and the CIELAB color system. Measurements were performed immediately after treatment at baseline (T0), at 1 month (T1), and at 2 months (T2). Color change between assessment periods was calculated using ΔE*ab values.

Patient-reported discomfort was assessed immediately after each half-mouth procedure using a visual analog scale. Total procedure time for each intervention was recorded with a stopwatch.

The primary outcome was color change from immediately after treatment to 2 months. Secondary outcomes included color change from immediately after treatment to 1 month, color change from 1 month to 2 months, patient discomfort, and procedure time.

A total of 34 participants completed all study visits and follow-up assessments.

• Guided Biofilm Therapy (Procedure), also known as GBT: Dental biofilm was first disclosed to guide treatment. Supragingival biofilm and extrinsic staining were then removed using an air-water-powder system with a low-abrasive erythritol-based powder. Supragingival ultrasonic instrumentation was performed where necessary, followed by final surface control.
• Conventional Polishing (Procedure), also known as CONV: Supragingival instrumentation was performed as needed, followed by mechanical polishing with a prophylaxis brush and polishing paste at 2500 to 3000 rpm. The procedure was completed with final surface control.

Primary outcomes

• Change in Tooth Color From Immediately After Treatment to 2 Months Assessed by CIELAB ΔE*ab Using a SpectroShade Micro Spectrophotometer [Immediately after treatment (Day 1) and at 2 months]: Tooth color was measured using a SpectroShade Micro spectrophotometer according to the CIELAB color system. Color change between immediately after treatment (T0) and 2 months (T2) was calculated as ΔEab using the formula: ΔEab = \[(ΔL*)² + (Δa*)² + (Δb*)²\]\^(1/2). ΔEab is a continuous color-difference measure, with 0 indicating no color difference and higher values indicating greater color change. Therefore, lower ΔEab values indicate greater color stability.

Secondary outcomes

• Change in Tooth Color From Immediately After Treatment to 1 Month Assessed by CIELAB ΔE*ab Using a SpectroShade Micro Spectrophotometer [Immediately after treatment (Day 1) and at 1 month]: Tooth color was measured using a SpectroShade Micro spectrophotometer according to the CIELAB color system. Color change between immediately after treatment (T0) and 1 month (T1) was calculated as ΔEab using the formula: ΔEab = \[(ΔL*)² + (Δa*)² + (Δb*)²\]\^(1/2). ΔEab is a continuous color-difference measure, with 0 indicating no color difference and higher values indicating greater color change. Therefore, lower ΔEab values indicate greater color stability.
• Change in Tooth Color From 1 Month to 2 Months [At 1 month and 2 months]: Tooth color was measured using a SpectroShade Micro spectrophotometer according to the CIELAB color system. Color change between 1 month (M1) and 2 months (M2) was calculated as ΔE*ab using the formula: ΔE*ab = \[(ΔL*)² + (Δa*)² + (Δb*)²\]\^(1/2). Lower ΔE*ab values indicate less color change.
• Patient-Reported Discomfort Assessed Using a 10-cm Visual Analog Scale [Immediately after completion of each half-mouth intervention (Day 1)]: Patient-reported discomfort was assessed immediately after each half-mouth procedure using a 10-cm visual analog scale ranging from 0 to 10, where 0 indicated no discomfort and 10 indicated unbearable discomfort. The score reflected the overall perception of pain or sensitivity, heat, pressure or vibration, and discomfort related to water spray or aerosol. Lower scores indicate greater patient comfort.
• Total Procedure Time Measured Using a Digital Stopwatch [Periprocedural]: Total procedure time for each intervention was recorded using a digital stopwatch. Timing began with the first clinical step of the relevant intervention and ended after completion of the final surface check. Patient preparation, isolation, and oral hygiene instruction were excluded. Procedure time was recorded in minutes and seconds, with shorter times indicating greater procedural efficiency.

Sex: All, ages: 18 Years to any, accepts healthy volunteers

Inclusion Criteria:

* Age over 18 years.
* Willingness to participate in the study and provision of written informed consent.
* Good general health with no systemic disease.
* Clinical presence of extrinsic staining on tooth surfaces at a level warranting professional polishing.
* Right-handed tooth brushing.
* No professional dental cleaning within the previous 6 months.

Exclusion Criteria:

* Age under 18 years.
* Diagnosis of periodontitis.
* Current smoking.
* Antibiotic use within the previous 3 months.
* Presence of acute periodontal disease.
* Allergy to polishing powders, specifically erythritol.
* Presence of a communicable disease.
* Teeth to be measured with restorations, caries, excessive wear, or structural defects that could affect measurement.
* Active orthodontic treatment.
* Developmental or structural anomalies affecting enamel and potentially increasing susceptibility to extrinsic staining, including hypomineralization, amelogenesis imperfecta, or dentinogenesis imperfecta.
* Severe dental crowding preventing standardized measurements.

• Study Protocol (PDF, 2026-10-02)
• Statistical Analysis Plan (PDF, 2026-10-02)

• Recep Orbak, DDS, PhD, Study director, Ataturk University