Comparative Evaluation of Enamel Surface Abrasion Produced by Three Different Types of Toothbrush Bristle Designs: An In-vitro Study

Introduction: The toothbrush is one of the most commonly used mechanical aids for plaque control, capable of removing plaque efficiently. However, improper toothbrushing habits can lead to tissue trauma, such as abrasion or gingival recession. The design of toothbrush bristles is one of the most common etiological factors for abrasion. Aim: To evaluate and compare the enamel surface abrasion produced by three different toothbrush bristle designs in conjunction with a standard dentifrice. Materials and Methods: In this in-vitro study conducted in the Department of Periodontics, Bharati Vidyapeeth Dental College and Hospital, Pune, Maharashtra, India, from June 2023 to January 2024, a total of 21 extracted human premolars were collected. After thorough cleaning, the teeth were stored in normal saline. The crown portions of the teeth were mounted on an acrylic resin base and profilometric analysis was performed to record the average enamel surface roughness (Ra) value. The teeth were randomly divided into three groups based on the toothbrush bristle design used for toothbrushing: Group A: Tapered bristle, Group B: End-rounded bristle, Group C: Flat- trim bristle. Toothbrushing was carried out using a customised toothbrushing device and a standard dentifrice twice daily for six weeks. After six weeks, profilometric analysis was conducted again. Descriptive statistics were expressed as means and standard deviations. The comparison of enamel surface abrasion among the three different toothbrush bristle designs was performed using the One-Way Analysis of Variance (ANOVA) test, followed by the post-hoc Bonferroni test for pair- wise comparison. In this test, a p-value less than or equal to 0.05 was considered statistically significant. All analyses were conducted using Statistical Package for the Social Sciences (SPSS) version 25.0. Results: The results showed significantly greater Ra values for Group C (flat-trim bristle: 0.13 +/- 0.06) compared to Group A (tapered bristle: 0.09 +/- 0.03) and Group B (end-rounded bristle: 0.04 +/- 0.02). Group B exhibited the lowest Ra value, indicating the least enamel surface roughness (p-value: 0.038*). Conclusion: Within the limitations of the study, stylus profilometer analysis demonstrated that the flat-trim toothbrush bristle design is more prone to causing enamel surface abrasion than the end- rounded and tapered bristle designs. The end-rounded toothbrush bristle design causes minimal enamel surface abrasion and is safer to use as an effective mechanical plaque control aid.