The Effects of Smoking on miRNA-223 Before and After Non-Surgical Periodontal Therapy

Periodontal diseases are one of the most common inflammatory diseases. Periodontal disease results from a complex interplay between the subgingival biofilm and the host immune-inflammatory events that develop in the gingival and periodontal tissues in response to the challenge presented by the bacteria. The net result of these inflammatory changes is the breakdown of the fibers of the periodontal ligament, resulting in clinical loss of attachment together with resorption of the alveolar bone. It is known that smoking is a major risk factor for periodontitis and affects the occurrence and severity of the disease and recovery after periodontal treatment by changing the host response to plaque. Biomarkers can be used to diagnose periodontitis early, to determine the rate of destruction, and also to evaluate the response to treatment. It has been reported that microRNAs (miRNAs) play an important role in development, homeostasis and immune functions, and abnormal miRNA expression may increase the severity of disease progression. It can be thought that early diagnosis can be achieved with the detection of miRNAs in patients with periodontitis, thus helping to prevent bone and tooth loss. To the best of our knowledge, there is no study in the literature investigating the effects of periodontal treatment and smoking on miRNAs in saliva or gingival samples. From this point of view, the aim of our study is to examine and compare miRNA-223 expressions in saliva and tissue samples before and after non-surgical periodontal treatment in individuals with periodontitis and to investigate the effect of smoking on miRNA-223 levels.

Materials-Methods: Our study will include 42 people with periodontitis and 42 healthy periodontal patients (84 individuals in total), and these two groups will be divided into two as smokers and non-smokers. Clinical measurements (Plaque index, probing depth, gingival recession, clinical attachment level, bleeding on probing) and salivary sample will be taken from all individuals at the beginning of the study. Non-surgical periodontal treatment will be applied to individuals with periodontitis, gingival samples will be collected during the treatment, clinical measurements and saliva collection will be repeated 6 weeks after the treatment. MiRNA-223 gene expression analysis will be performed by real-time PCR method in saliva and gingival samples of individuals. MiRNA-223 and cotinine levels will be examined to evaluate the effects of smoking before and after treatment in periodontal health and periodontitis.

With our study, it is aimed to better illuminate the role of miRNA-223 in periodontitis and also to determine which sample is more reliable by comparing miRNA-223 levels in saliva and tissue samples. Thus, the first step towards the development of diagnostic kits in the future will be taken.