Chronic periodontitis is an infectious disease resulting in inflammation within the supporting tissues of the teeth, progressive attachment loss and bone loss. (1) The progression of the disease is related to the colonization of microorganisms in the gingival crevice and periodontal pockets of a susceptible host. The process of periodontal pocket formation represents the pathological sequel of microbial- and inflammatory-mediated degradation of collagenous connective tissues and alveolar bone. (2) World Health Organization (WHO) in its report in 2005 published that almost 10-15 % of the population worldwide is suffering from severe form of periodontitis. (3) Chronic periodontitis is the most common form of periodontitis which is more prevalent in adults but can occur in children as well characterised by low to moderate rate of progression, with possible periods of rapid progression. Analysis of epidemiological studies on oral disease in Nepal has concluded that 29 % of Nepalese aged 35-44 years are suffering from deep periodontal pockets. (4) Therapeutic approaches for the periodontal diseases must include the modalities that will target the microorganisms as well as modulate the destructive host response. (5) The effective elimination of the plaque mass and the microorganisms by scaling and root planing have been well documented, but the inability to access deep and tortuous pockets has proven to be a major drawback. (6) In addition to mechanical treatment, the use of antimicrobial agents, both systemic and topical, has been increasing because of the realization that 2 periodontal disease is not merely an overgrowth of bacteria, but also a shift in bacterial species. (7) This had led to the adjunctive use of antimicrobial agents usually in the form of irrigants or systemic antibiotics to overcome the limitations of conventional treatment. These procedures however were questionable as antimicrobial irrigants did not seem to be effective enough and subjecting a patient to a long term systemic administration of antibiotics was not feasible. It was for this reason that local drug delivery systems evolved, in order to achieve antimicrobial activity at the base of the pocket and remain active for a time to inhibit growth of pathogenic bacteria. (8) Goodson et al in 1979 first proposed the concept of controlled delivery in the treatment of periodontitis. (9) Malathi et al. concluded that locally delivered antimicrobial agents are administered to prevent plaque accumulation and to disinfect the root surface and adjacent periodontal tissues and are designed to enhance the healing following periodontal therapy. (10) Different antibiotics such as tetracycline, nitroimidazoles, fluoroquionolones and macrolides have been used as local drug delivery agents in various studies with promising clinical and microbiological results . (9) As an antiseptic, chlorhexidine (CHX) has been used effectively for >30 years. (11) Of all the chemical plaque control agents, chlorhexidine has proven to be the most effective, safe and clinically effective in reducing plaque and gingivitis. (12) Chlorhexidine (CHX) is a widely used broad-spectrum antimicrobial agent to inhibit bacterial growth and, thus, an adjunctive mean to control oral hygiene in patients with periodontal disease. (13) A bioabsorbable chlorhexidine chip has been introduced that enables slow subgingival release of 2.5 mg chlorhexidine, maintaining an average concentration of >125 mg/ml for >7 to 10 days in the 3 crevicular fluid. (14) This concentration has been reported to be above the minimum inhibitory concentration for >99% of the subgingival microorganisms isolated from periodontal pockets. (15) CC (Periochip) is the only locally applied non-antibiotic antimicrobial approved by the FDA as an adjunct to SRP procedures. CC used following SRP was determined to be effective in reducing probing depth (PD), clinical attachment level (CAL) and bleeding on probing compared to SRP alone in chronic periodontitis. (16) Similar results were obtained in a multicentered study conducted by Jeffcoat et al. (8) and recently reviewed by Cosyn and Wyn. (17) In contrary, Daneshman , Grisi (18) (19) in a small group of patients, did not observe any adjunctive effects of the chlorhexidine chips compared to scaling and root planing alone over 9 months in periodontal pockets ≥5 mm deep. Thus, there are conflicting reports regarding the adjunctive effects of chlorhexidine chips, indicating the need for additional research. Therefore, the aim of this study is to evaluate the effectiveness of a chlorhexidine chip as an adjunctive therapy to scaling and root planing in the treatment of chronic periodontitis.

 4 Rationale of study: The present study helps to find the answers to things that are unknown and fills gaps in knowledge. This will be the first study of its kind evaluating whether chlorhexidine chip provides additional benefit in the treatment of chronic periodontitis in our Nepalese population. It helps to find out which treatments work better for the patients. It is expected that performing this research will make it possible to 

 better understand that a sustained release device is a less invasive treatment option and requires less time compared to surgical treatment. 

 Place an antibiotic or antiseptic in direct contact with the root surface so that pathogenic organisms that are not accessible to mechanical removal by hand or power-driven instruments can be reduced or eliminated. 

Be used as an adjunct to scaling and root planing and adjunctive locally administered antimicrobials improved probing depth over SRP alone in chronic periodontitis patients. 

 Be used in periodontal maintenance therapy. 

Counsil the patient accordingly for the local delivery of antimicrobial agents during the treatment of periodontal disease.

 5 REVIEW OF LITERATURE 

 Several studies have been conducted in the past for the determination of effectiveness of chlorhexidine chip. 

 Stanley Wilson Newman (1989) (15) study determined the susceptibility to chlorhexidine of a range of bacteria which may be isolated from subgingival plaque. In addition, the effect of chlorhexidine on the survival of bacteria in subgingival plaque samples from patients with chronic inflammatory periodontal disease was investigated. The minimum inhibitory concentration (MIC) of chlorhexidine for 52 strains of bacteria ranged from 8 to 500 //g/ml. The modal value of the MIC was found to be 62 //g/ml, 64% of the strains tested being inhibited at this concentration. A concentration of 250 //g/ml of chlorhexidine inhibited the growth of all bacteria in the 25 subgingival plaque samples investigated. The MIC of chlorhexidine for the samples ranged from 31 to 250 /µg/ml, the modal value being 125 µg /ml. 

 Greenstein, Polson (1998) (20) review article evaluates the role of local drug delivery systems in the management of periodontal diseases. The efficacy of several local delivery devices (i.e., tetracycline fibers, metronidazole and minocycline gels, Chlorhexidine chips, and doxycycline polymer) which are either commercially available in the United States or abroad or are currently under consideration for Food and Drug Administration (FDA) approval are discussed. The drug delivery systems are assessed with regard to their functional characteristics, effectiveness as a monotherapy, as compared to scaling and root planing, and ability to enhance conventional therapy. Furthermore, controversies associated with local delivery are addressed. 

 Jeffcoaat (1998) (8) evaluated the efficacy of a controlled-release biodegradable Chlorhexidine (CHX) (2.5 mg) chip when used as an adjunct to scaling and root planing on reducing probing depth (PD) and improving clinical attachment level (CAL) in adult Periodontitis. Two double-blind, randomized, placebo-controlled multicenter clinical trials (5 centers each) were conducted; pooled data are reported from all 10 centers (447 patients). At baseline, following 1 hour of scaling and root planing (SRP) in patients free of supragingival calculus, the chip was placed in target sites with PD 5 to 8 mm which bled on probing. Chip placement was repeated at 3 and/or 6 months if PD remained > 5 mm. Study sites in active chip subjects received either CHX chip plus SRP or SRP alone (to maintain study blind). The proportion of patients who evidenced a PD reduction from baseline of 2 mm or more at 9 months was significantly greater in the Chlorhexidine chip group (19%) compared with SRP controls (8%) (P < 0.05).

 Haesman (2001) (21) determined the efficacy of controlled-release delivery of chlorhexidine gluconate 2.5 mg (PerioChipTM) in patients with residual bleeding pockets (.5 mm) at least 3 months following oral hygiene and root debridement phase therapy. The result suggest that PerioChipTM is beneficial for patients on maintenance therapy although the benefit is not apparent until 6 months after placement. Azmak (2002) (13) evaluated the efficacy of controlled- release delivery of chlorhexidine gluconate (CHX) on clinical parameters and on gingival crevicular fluid (GCF) matrix metalloproteinase (MMP)-8 levels in chronic periodontitis patients. Twenty patients with chronic periodontitis were screened for 6 months. Two interproximal sites were selected from mesial 7 surfaces of anterior teeth with probing depths of 6 to 8 mm that bled on probing in each patient. There were at least 2 teeth between the selected sites. GCF MMP-8 levels were analyzed at baseline; 2 and 10 days; and at 1, 3, and 6 months by immunofluorometric assay (IFMA). Result suggest that CHX chip application following SRP is beneficial in improving periodontal parameters and reducing GCF MMP- 8 levels for 6 months‟ duration.

 Paolantonio (2008) (22) examined 116 systemically healthy individuals with moderate to advanced periodontitis, aged 33 to 65 year. The aim was to provide data on the clinical and microbiologic effects of CHX chips when used as an adjunct to SRP. When all of the pockets were considered, the PD and RAL were significantly less at 3 and 6 months compared to the baseline scores (P <0.01) for both treatments. Moreover, the PD was reduced in the SRP + CHX treatment group compared to the SRP treatment group at 3 and 6 months, whereas the RAL was similar for both treatments at 3 months and was reduced in the SRP + CHX treatment group at 6 months. Both treatments generally reduced the percentages of sites positive for the eight putative periodontopathic bacteria, although greater reductions were seen often for the SRP + CHX treatment group. 

 Machtei (2011) (23) in randomized, double blind, parallel, 2-arm clinical study was to examine the safety and efficacy of frequent applications of chlorhexidine chip (CHX) and flurbiprofen chip (FBP) in patients with chronic periodontitis in which Sixty patients were randomized into CHX and FBP groups. Following OHI and scaling and root planing (SRP), baseline pocket depth (PD) measurements, gingival recession and bleeding on probing (BOP) were performed and repeated at week 4 and 8 which concluded that frequent 8 applications of CHX and FBP chips resulted in a significant improvement in the periodontal condition in these sites.

 Kondreddy (2012) (24) selected 40 posterior sites of 20 patient to evaluate the effectiveness of a controlled-release chlorhexidine chip as an adjunctive therapy to scaling and root planing when compared with scaling and root planing alone in the treatment of chronic periodontitis. The clinical parameters (Plaque index, bleeding on probing, probing pocket depth, clinical attachment level) were recorded at baseline, 90th and 180th day for both the groups. When both groups were compared the change in Plaque index was significantly higher in Group B when compared to Group A on the 90th day and 180th day. However, there was no statistically significant difference in the mean percentage of gingival bleeding sites between the two groups on the 90th day, though Group B showed a statistically higher reduction in the mean percentage of gingival bleeding sites at the end of 180th day. There was no statistically significant difference in probing pocket depth between the two groups on both 90th and 180th day. Gain in clinical attachment level was significantly higher in Group B when compared to Group A on the 90th and 180th day. 

 Lecic (2016) (25) examined 120 periodontal pockets in this randomized, controlled, split mouth designed study to evaluate clinical efficacy of different chlorhexidine gluconate (CHX) preparations applied sub gingivally as an adjunct to scaling and root planing (SRP) which favored combination therapy using CHX chip as an adjunct to SRP due to greater improvements in BI and PPD compared to those obtained by SRP alone in the treatment of chronic periodontitis. 9 Jose (2016) (26) selected fifteen chronic periodontitis patients having a probing pocket depth of 5mm-7mm on at least one interproximal site in each quadrant of the mouth. The aim was to evaluate the effects of diode laser and chlorhexidine chip as adjuncts to scaling and root planing in the management of chronic periodontitis. It concluded that Chlorhexidine local delivery alone or in combination with diode laser decontamination is effective in reducing probing pocket depth and improving clinical attachment levels when used as adjuncts to scaling and root planing in non-surgical periodontal therapy of patients with chronic periodontitis.

 Few researches which showed no improvement in periodontal parameters when CC is used as an adjunct to SPR are as follow: 

 Grisi (2002) (19) evaluated the effectiveness of a controlled- released chlorhexidine chip (CHX) as adjunctive therapy to scaling and root planing (SRP) in the treatment of chronic periodontitis in twenty patients with at least four sites with probing depth ≥ 5mm and bleeding on probing. This randomized single-blind study was carried out in parallel design. The control group received SRP alone, while the test group received SRP plus CHX chip. The clinical parameters and the microbiological parameter BANA test were recorded at baseline and after 3, 6 and 9months. Result concluded that the CHX chip did not provide any clinical or microbiological benefit beyond that achieved with conventional scaling and root planning, after a 9- month period. 

 Cosyn Wyn (2006) (17) reviewed five studies following independent screening by two reviewers which concluded that the clinical and microbiological data currently available on the chlorhexidine chip are limited 10 and conflicting. More research is needed to elucidate the additional value of the chlorhexidine chip when used as an adjunct to scaling and root planing. 

 Carvalho, Novak, Mota (2007) (27) 9-month study was to compare the effect of scaling and root planing alone (control) to that of scaling and root planing plus application of chlorhexidine chips (test). In this split mouth trial, twenty-six subjects having two non-adjacent sites in non-molar teeth with probing depth ≥5mm and bleeding on probing participated. Recordings of bleeding on probing, probing depths, and clinical attachment levels were performed at baseline, after 6 weeks, and after 3, 6, and 9 months which resulted in improvements of bleeding scores, probing depths and clinical attachment levels for both test and control sites at 6 weeks compared to baseline. Subsequently, all three measurements remained comparatively stable through- out the study. No differences in improvements were found comparing test and control sites. This study failed to observe any adjunctive effect of subgingival placement of chlorhexidine chips after scaling and root planning.

 Research hypothesis (alternative) 

There is significant reduction of CAL and PPD achieved for chlorhexidine chip compared to SRP alone. 

12 MATERIAL AND METHODS 

 a. Type of study design: Randomized clinical trial 

 b. Population/ participants: Human only

 c. sample selection criteria: Purposive sampling technique with computer generated allocation 

d. Control group: There will be control group in the study 

 e. Setting: This will be hospital-based study 

 f. Probable duration of the study: 12 months 

 g. Ethical clearance: Will be obtained as per the guidelines from the Institutional Review Committee, BPKIHS 

 h. Conflict of interest: None i. Sampling technique: purposive  sampling technique

 j. Methods of Randomization (in case of RCT) and blinding: simple randomization (computer generated allocation ) and simple blinding technique 

 Methods

: a. Instruments/questionnaire: It is an instrument-based study. The clinical periodontal examination will be carried out manually using UNC-15 probe (University of North Carolina-15 probe, it is 15 mm long with markings at each mm and color coding at 5th, 10th and 15th mm) and Mouth mirror. Patients fabricated cast with dental stone will be used. Custom made acrylic occlusal stent with groove for precise alignment of probe will be used. 

 b. Frequency and duration of intervention/follow up of subjects (if relevant After the initial intervention on the 7th day of baseline, patient will be recalled for follow ups on 1 week (for coe – pack removal) 1 month and 3 months for evaluation of clinical parameters (PPD, CAL, PI, BOP) and deplaquing will be undertaken according to the clinical need

 c. Procedure and Schedule: Chronic periodontitis has been defined as “an infectious disease resulting in inflammation within the supporting tissues of the teeth, progressive attachment loss and bone loss” Patients of chronic periodontitis having ≥5 to 7 mm of pocket diagnosed on the basis of clinical and radiographic features will be included as per inclusion and exclusion criteria of study from Outpatient examination(OPE) on daily basis from Department of Periodontology and Oral Implantology, College of Dental Surgery, B. P. Koirala Institute of Health Sciences, Dharan, Nepal. Patients will be selected on the basis of inclusion criteria. All examinations will be performed by one trained examiner who will not be involved in any aspect of the therapy. The periodontal examinations include PI, BOP, PPD, CAL. Randomization of patients for periodontal therapy will be done by Lottery method. Group-A (control site) allocated for scaling and root planing alone Group-B (test site) for scaling and root planing and CC. One separate box will be allocated for each SPR or SRP plus CC group which consists of 50 written paper slip in it. Patient will be allowed to pick one slip for his/her therapy and treatment will be done according to picked written slip by patient. Coding system A for SRP group and B for SRP plus CC group will be used in Proforma during allocation of group to reduce bias at time of measurement of patient. Impression of gingiva and teeth of patient will be made with alginate impression material and then cast will be fabricated with dental stone. Customized acrylic stent will be fabricated with cold cure acrylic on cast with fixed reference point. Finishing and polishing of stent will be done with 15 acrylic bur, stone bur and sand-paper bur. PPD and CAL will be measured with the help of customized acrylic, occlusal stent with constant reference point for precise alignment of UNC 15 periodontal probe on cast. PPD, CAL, BOP and PI will be measured at baseline and at interval of 1 month, 3 months. Patients meeting the inclusion criteria of both the groups will receive supragingival scaling appointment of 60 min or less (13) to make the sites free of supragingival calculus prior the baseline . At 7th day, all patients in both the groups will received complete subgingival scaling and root planing with ultrasonic scaler(cavitron) and hand instrument (Hufriedy). whereas group B will receive SPR with chlorhexidine chip. Each appointment will last for 2 hour. In the test group sites, before inserting the chip, the area will be dried with the cotton rolls. The flat end of the CC will be grasped with a tweezer and the rounded end of the chip pressed apically into the test site, so that the chip rested sub gingivally at the base of the pocket and making sure that it won‟t be exposed. Then the periodontal pack will be placed. The patients will be instructed to continue with regular oral hygiene measures, except for the use of chemotherapeutic mouth rinses and oral irrigation devices. All patient from group B will be recalled after 7 days for pack removal. Pre-therapy PPD and CAL will be recorded by measuring from the lower end of stent fixed reference point (FRP) to the base of the pocket of selected tooth in both group A and group B. Those patients in which pocket depth persists more than 5mm in non-surgical group, surgery will be planned after 6 months. The postsurgical measurements will be done by the same trained 16 investigator who will be blinded for 2 groups. Change in PPD and CAL determined by comparing post and pre-periodontal therapy at each site. d. Dosage, formulations, schedules, duration of drug treatments/surgical technique, suture (if relevant) not applicable

 19 DATA MANAGEMENT AND STATISTICAL ANALYSIS 

 a. Data handling: The entire questionnaire will be checked for its accuracy in every month. Collected data will be entered in Microsoft excel 2016 and again checked on every 10 entry to avoid entry error. The obtained data will be converted into Statistical Package for Social Science (SPSS) for statistical analysis. 

 b. Coding: A coding list will be prepared. On the basis of coding data will be entered into computer through MS excel 2016.

 c. Monitoring: Supervision and monitoring will be done for entered data by guide and co-guide at regular interval

 d. Statistical methods proposed: The excel data will be converted into Statistical Package for Social Science (SPSS, version 16) for statistical analysis. Percentage distribution of subjects with Chronic Periodontitis will be tabulated in each group and with change in clinical attachment level after periodontal therapy. Descriptive statistics will be used to explore characteristics of numeric data, calculation of mean, standard deviation and range. Normality of variables will be checked. Student‟s t test or Mann Whitney U test will be used to compare the clinical parameters in between two groups. Paired sample t test or Wilcoxon‟s signed rank test will be used to compare the variables into the same groups in each follow up. Probability of significance will be set at 5% level. 20 e. Calculation of the sample size According to a literature Kondreddy,et al in 2012, the mean ± SD of clinical attachment level as a clinical parameter among test and control groups have been reported as 1.3 ± 0.5 and 1.8 ± 0.6 respectively. Considering the minimum difference of 0.5 in CAL in between the groups and pooled SD of 0.55 of two groups, the sample size has been calculated for two means comparison. We need to enrolled 25 cases in each group to be able to reject the alternative hypothesis that both the means are equal with 90% power and 95% Confidence interval. 

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LIST OF ABBREVIATIONS 

 BOP : Bleeding on Probing 

 CAL : Clinical Attachment Level 

 CC : Chlorhexidine Chip 

 FRP : Fixed Reference Point 

 OHI : Oral Hygiene Instruction

 PI : Plaque Index

 PD : Probing depth 

 PPD : Probing Pocket Depth

 SPR : Scaling and Root planing 

 SD : Standard Deviation