Aims To evaluate and compare changes in salivary flow rate and salivary levels of TIMP-1 and TIMP-2 in individuals taking oral Isotretinoin (INN) with those who do not take INN. To assess the variation in TIMP-1 and TIMP-2 as well as salivary flow rate observed at different stages of periodontal disease in comparison to those observed in the case of healthy periodontium. Materials and methods An examiner-blind case-control study involving 180 human adults divided into six groups based on their periodontal status. Clinical parameters, including pocket depth, clinical attachment level, and bleeding on probing were measured at six sites per tooth. Whole unstimulated saliva samples were collected from all subjects to evaluate salivary flow rate (SFR). Salivary TIMP-1 and TIMP-2 levels were detected using enzyme-linked immunosorbent assay (ELISA). Data were analyzed using IBM SPSS Software. The Kruskal Wallis test and Mann-Whitney U-tests were employed to verify any significant differences between the groups for all parameters. Multi-regression analysis was performed for each parameter tested in each group. All tests were compared at a significance level of 0.05. Results SFR was statistically significantly lower among all INN groups in comparison to the control groups ( P < 0.001). TIMP-1 and TIMP-2 were significantly higher in all INN groups in comparison to the control groups, in both gingivitis cases ( P = 0.004, P < 0.0001 respectively) and periodontitis cases ( P < 0.0001). Conclusion Although INN reduces salivary flow rate, the findings of the present study revealed that it had an anti-inflammatory effect in periodontal biomarkers. Specifically, it was positively correlated with an elevation of salivary TIMP-1 and TIMP-2. Hence, INN might be a future additive medication to be further evaluated for the treatment of periodontal diseases.

Introduction 3. Material and methods 3.1 Ethical approval and study sample 3.2 Subjects 3.3 Clinical measures 3.4 Intra-examiner and inter-examiner reliability 3.5 Saliva collection and samples preservation 3.6 Enzyme-linked immuno-sorbent assays 3.7 Data analysis 4. Results 4.1 Intra-examiner and inter-examiner reliability 4.2 Clinical measures 4.3 Enzyme-linked immunosorbent assay (ELISA) 5. Discussion 6. Author contributions 7. Ethics approval and consent to participate 8. Acknowledgment 9. Funding 10. Conflict of interest 11. References

Isotretinoin (INN), a drug used to treat severe acne, has anti-inflammatory and antibacterial properties. INN may affect periodontal pathogenic bacteria, so we aimed to study the effect of INN on intraoral microbial profiles of periodontal disease and healthy periodontium. Our case-control study divided 180 subjects into six groups according to periodontal health status and INN usage as follows: healthy periodontium receiving INN (HINN; n = 30); those with generalized plaque-induced gingivitis receiving INN (GINN; n = 30); and those with stage I generalized periodontitis receiving INN (PINN; n = 30). Subjects not taking INN, were categorized in the same manner: those with a healthy periodontium (HC; n = 30); those with generalized plaque-induced gingivitis (GC; n = 30); and those with generalized periodontitis stage I (PC; n = 30). Plaque samples were collected to determine the prevalence of four periodontal pathogens (Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Fusobacterium nucleatum) in each study group using real-time polymerase chain reaction. Data were analyzed using IBM SPSS software, and multiple regression analysis was performed for each parameter tested in each group at a significance level of 0.05. All INN groups showed significantly lower levels of P. gingivalis, T. forsythia, and T. denticola and higher levels of F. nucleatum (p < 0.001). INN had an observable antimicrobial effect on the periodontal pathogen count in patients with plaque-induced gingivitis and chronic periodontitis. INN may have a potential additive antimicrobial value in the treatment of periodontal disease.