Effect of Nonsurgical Periodontal Therapy Verses Oral Hygiene Instructions on Clinical Parameters as Well as Immunological and Microbial Profile of Patients With Chronic Periodontitis

Subjects with moderate to advanced chronic periodontitis were selected for this longitudinal randomized clinical trial. Ethical clearance for the study was granted by the Medical Ethics Committee, Faculty of Dentistry, University of Malaya [Medical Ethics Committee Number: DF PE1002/0045(P)]. The study was conducted in accordance with the Helsinki Declaration of 1975, as revised in 2000. The CONSORT guidelines for clinical trials were followed.

Out of 112 screened patients 56 patients fulfilled the inclusion and exclusion criteria. Inclusion criteria were minimum of 12 teeth present with pocket of 5mm or more and probing attachment loss of 4mm or more in at least 2 different quadrants which bled on probing. Exclusion criteria included history of cardiovascular problems, pregnancy, smokers, and subjects receiving antibiotics in past 4 months or NSPT in past 6 months. Recruited patients were treated at the Periodontology clinic, Faculty of Dentistry, University of Malaya. Using Cohen's d formula it was calculated that at least 26 patients would be needed per treatment group to detect this difference with 80% power.

Prior to baseline examination, patients were assigned in the NSPT and OHI group using block randomization. Patients in NSPT group received OHI, scaling and root planing followed by 0.12% Chlorhexidine mouth rinses while patients in OHI group received OHI only. At each month recall visit, participants in both groups were reviewed and motivated. Professional prophylaxis was only received by NSPT group. Two calibrated examiners (RPCR and WNAWA) performed all treatment on the patients. Probing pocket depth ( PPD), probing attachment loss (PAL), gingival bleeding index (BI) and visible plaque index (PI) were determined on all present teeth except third molars at baseline and 3 months after therapy. For PI and BI, 4 sites were measured (mesial, distal, buccal, lingual) and for PPD and PAL 6 sites were recorded (disto-buccal, mid-buccal, mesio-buccal, mesio-lingual, mid-lingual and disto-lingual). Utilizing Kappa statistics, good agreements (>0.8) were obtained for intra and inter operator reproducibility of all recorded clinical parameters.

Identification of subgingival microbiota using quantitative polymerase chain reaction technique.

Sub-gingival plaque scraping samples were obtained at baseline and 3-months post therapy with sterile curettes from the deepest sites at each quadrant and were pooled together for each subject. Prior to sampling, isolation was maintained with cotton rolls and supra-gingival plaque was removed using cotton pellets. Plaque scrapings were re-suspended in 1.5 ml of Phosphate Buffered Saline and stored at -80⁰C freezer prior to DNA extraction. 100µl of plaque sample was used for automated DNA extraction in the lab using the Qiacube machine (Qiagen®, Biotechnology, Netherlands). The tubes containing the plaque samples were centrifuged at a speed of 5,000 × g for 10 minutes on a tabletop centrifuge machine to obtain the pellet. The pellet was then used for automated DNA extraction with the Qiacube machine. 100µl of eluted DNA was stored in -20⁰C for bacterial detection using quantitative polymerase chain reaction (Applied Biosystem, USA).