Analysing root roughness and smear layer relationship by comparing contemporary dental curettes with conventional dental curettes: a randomised controlled trial

BACKGROUND: Root debridement procedures for the treatment of periodontal diseases, produces root surface irregularities and smear layer on the root surface that can adversely affect the healing of periodontal tissues. The objective of the present study was to evaluate the surface texture of root after hand instrumentation with Gracey curette, After Five curette, and Mini Five curette. METHODS: A randomised, controlled clinical trial was conducted with 120 participants clinically diagnosed with chronic periodontitis. Participants were equally randomised into four groups, with parallel treatment assignment of scaling and root planning using Gracey Curettes, After five and Mini five curette, and a control group with no instrumentation. Mobile teeth of these patients were then extracted atraumatically and analysed under a Scanning Electron Microscope and graded for "Roughness and Loss of Tooth substance index" and "Smear layer index." Cross Tabulation was made between the test groups (Control, Gracey Curette, After five, and Mini Five) versus "Roughness and Loss of Tooth substance Index" and "Smear Layer Index." A Chi-square test with Bonferroni correction was used to determine the graded distribution among the groups. RESULTS: In the control group, 73.3% of the teeth showed grade 1 roughness. In the Gracey group, 56.7% showed grade 2 roughness; in the After 5 group, 70% showed grade 3 roughness; in the Mini 5 group, 76.7% showed grade 3 roughness. A significant association was found between roughness scores and the use of individual instruments. Regarding smear layer formation, 46.7% of teeth showed a grade 4 smear layer in the control group. 50% of teeth showed grade 2 smear layer thickness in the Gracey group. In the After 5 group, 73.3% of teeth showed a grade 1 smear layer, while in the Mini 5 group, 80.0% showed a grade 1 smear layer. The use of individual instruments was significantly associated with the smear layer scores. CONCLUSION: Gracey curettes produced relatively smoother root surfaces with less smear layer formation than After Five and Mini Five curettes, which produced relatively more roughened root surfaces with thicker smear layer formation. TRIAL REGISTRATION: ID: ClinicalTrials.gov Identifier: NCT04216966 Date of Registration: January 3, 2020.