The study was conducted in the outpatients Department of Periodontics, Mar Baselios Dental College, and Kothamangalam. The study design was a prospective randomized single blinded clinical trial. Randomization was done by chit method. The study was approved by the institutional ethical committee. Fifteen patients fulfilling the inclusion and exclusion criteria were included in the study. There were 9 males and 6 females belonging to the age group of 30 – 60 years. The purpose of the study was explained to the patients and written informed consent was obtained.

In all selected patients, a full mouth supragingival ultrasonic scaling was done. At the start of the study oral hygiene instructions were given and clinical parameters namely Plaque Index (PI), Gingival Index (GI) [14], probing pocket depth (PPD) and clinical attachment level (CAL) were recorded in all selected patients [Table/Fig-1a].

[Table/Fig-1]:

Probing pocket depth measured using stent: a) Baseline; b) 1 month; c) 3 months.

After 2 weeks in each patient one interproximal site in each quadrant with a probing pocket depth of 5mm-7mm was randomly assigned to receive one of the following treatment modalities by chit method. One of the site assigned as control group was subjected to scaling and root planing (SRP). The other three sites in addition to SRP received laser decontamination (diode laser group), chlorhexidine chip application (CHX chip group) or both (diode laser and chip group). In the control site scaling and root planing (SRP) was done by area specific curettes (Hu – Friedy Chicago IL). Following SRP the laser treatment was performed by Gallium-Aluminium -Arsenide (GaAlAs) diode laser (AMD, Picasso U.S.A) with a tip diameter of 400 μm, optical fiber that emitted light at wavelength of 810nm. The fiber was inserted into the periodontal pocket (1mm short of measured periodontal pocket depth) almost parallel to the tooth and moving from apical to coronal directions continuously. Power setting of 0.5 watts in continuous mode and time duration of 10 seconds per site was used. Both patient and operator wore protective eyeglasses during laser decontamination [15].

Chlorhexidine Chip placement [Table/Fig-2]: Following SRP the area was dried, and the chlorhexidine chip (Periocol –CG, Eucare pharmaceuticals, Chennai) was inserted into periodontal pocket with tweezers. The flat end of chlorhexidine chip was grasped with a sharp tweezer and the curve end was first inserted into periodontal pocket. Periodontal dressing (Coe-pak, GC U.S.A.) was placed on sites where chlorhexidine chip application was done. All the patients were recalled after 10 days for evaluation of any displacement of chip. Each chip contains approximately 2.5mg of chlorhexidine in a biodegradable matrix of collagen type I derived from the air bladder of fresh water fishes. The size of the chip is 4x5mm and thickness is 0.25-0.32mm, and its weight is about 10mg. It is resorbed in 30 days; however, the coronal edge is degraded in just 10 days. Laser decontamination and CHX chip application: Laser decontamination procedure was performed which was followed by chlorhexidine chip application. Re-evaluation and all clinical parameters were recorded at 1 month and 3 months [Table/Fig-1b&c]. The data was recorded at all intervals by a same examiner who was blinded for the procedure.

[Table/Fig-2]:

a) Laser decontamination; and b) chlorhexidine chip application.

Statistical analyses were performed using SPSS 16.0. Descriptive analyses were performed by the calculation mean and SD. The data were analysed by paired t-test, one-way-ANOVA, Tukey’s HSD test and repeated measure ANOVA. A statistical significance was assumed when p<0.05.

All the15 subjects completed the study uneventfully.

The baseline values of all four parameters were not statistically significant between any groups as determined by one-way ANOVA. Tukey’s HSD test was done to analyse statistical significant difference between different groups at one month and three months. The mean reduction in plaque index score [Table/Fig-3], Gingival Index score [Table/Fig-4], mean reduction in probing pocket depth [Table/Fig-5] and mean gain in relative clinical attachment level [Table/Fig-6] were statistically significant between both the interval i.e. baseline to one month (p< 0.01) and baseline to three months (p<0.01) in all the four groups.

The change in mean reduction of PPD compared to control group was 0.06mm, 1.20mm and 1.33mm in diode laser group, Chlorhexidine chip group and combination group respectively. Comparison of SRP with diode laser group showed insignificant result in PPD reduction (p<0.994) and mean gain in rCAL (p<0.993). However, comparison of SRP with CHX chip group and combination group revealed statistically significant improvement in PPD and rCAL (p< 0.01). Comparison of PI and GI based on groups at one month and three months shows no significant changes between any groups (p>0.05). Comparison between adjunct groups showed significant difference in PPD reduction and mean gain in CAL except between CHX group and combination group [Table/Fig-7,8].

Periodontal diseases comprise a group of chronic inflammatory lesions initiated and propagated by the accumulation of sub gingival biofilm. The removal of these biofilms and their retentive factors like calculus remains the cornerstone of the periodontal therapy. Mechanical sub gingival debridement i.e., scaling and root planing is considered as the gold standard of nonsurgical periodontal procedure. Previous studies indicates that the treatment of pockets by scaling and root planing followed by routine maintenance therapy every three months results in the maintenance of attachment levels and the reduction of probing depths [16,17]. In view of the current knowledge related to the nature of disease progression and studies showing that deep pockets can be maintained without further attachment loss, our approach to surgical pocket therapy has been changing. Periodontal disease therapy has therefore been directed at altering the periodontal environment to one which is less conducive to the retention of bacterial plaque [18].

Scaling and root planing has been shown to be an effective treatment for periodontitis. Mechanical therapy may however fail to eliminate the pathogenic bacteria because of their location within gingival tissues or in other areas inaccessible to periodontal instruments [19]. As the depth increases to ≥ 5mm, scaling and root planing becomes progressively less effective [20]. This has led to the development of alternative or adjunct treatment that might provide added benefits along with scaling and root planing. Mechanical and adjunct measures to minimize or eliminate bacterial plaque have been used in periodontal therapy in the past with varying results. Clinical trials on local drug delivery using chlorhexidine chip and diode laser decontamination have reported conflicting results in clinical and microbiological parameters of periodontal disease.

The present study was done to compare the effects of chlorhexidine chip, diode laser irradiation and the combination of both as adjuncts to SRP. A split mouth design involving one interproximal site from each quadrant was selected. In this type of study design, the patient is matched to himself, or serves as his own control, is recognized as having the ability to greatly facilitate the interpretation of trials by minimizing the effects of inter-patient variability. However, in split mouth design, when comparing different treatment modes within the same dentition, carry across or spill-over effects may occur [21]. Hence, to eliminate the carry-across effects on experimental sites, the present study randomly selected sites which were at least three teeth apart, possibly minimizing the interaction between therapy modes [22]. No side effects were observed or reported subsequent to the chlorhexidine chip application and laser decontamination, which indicated the safety of the procedure.

Even though oral prophylaxis was done at baseline, it was repeated after 2 weeks, because to standardize and compare with gold standard procedures of non surgical therapy and to avoid bias.

The inter group comparison of plaque index and gingival index showed insignificant differences between all groups at three months. However, more reduction was seen with test groups when compared with control (SRP) group. This might be attributable to the added interventions at the test sites.

Present study showed no significant improvement in pocket depth and clinical attachment gain in laser group when compared to control group. This result was controversial to studies conducted by Moritz A et al., Dukic et al., that showed a significant improvement [23,24]. This conflicting result may be due to the higher power settings and multiple radiations used in those studies.

To augment mechanical debridement, topical antiseptics are used to kill periodontal pathogens at the initial therapy and to suppress their repopulation in the maintenance phase. This concept of controlled- release local delivery of therapeutic agents was developed into a viable concept by Dr. Max Goodson in 1979. Local delivery systems containing antibiotics or antiseptic drugs allow the therapeutic agents to be targeted to the diseased site with minimal systemic effects. Local delivery systems when retained in the pocket can release the antimicrobial agents at levels that are 10-100 folds higher than the levels that can be delivered by systemic antibiotics. This approach also addresses the critical concern of unnecessarily exposing the patient to large doses of systemic antibiotics, which can also result in bacterial resistance. Chlorhexidine has wide spectrum of activity encompassing gram-positive and gram negative bacteria, yeast and some lipophilc viruses. Friedman and Golomb developed the first slow-release device containing chlorhexidine. Controlled delivery system has duration of drug release more than 24 hours. The effects of locally delivered controlled-release chlorhexidine have been shown to be evident upto 11weeks [25] which corresponds to 3 months. In this study CHX chip group comparison with control group showed statistically significant reduction in PPD and mean gain in CAL. Birang et al., Puri K et al., Kumar AJ et al., Grover V et al., and Kondreddy K et al., reported results similar to our study [12,26–29].

Intergroup comparison of test groups revealed that the CHX chip group and combination of laser decontamination and chlorhexidine chip group showed statistically significant difference in PPD reduction and gain in CAL compared to diode laser group at three months. But comparing chlorhexidine group with combination group there was no statistical significance this can be interpreted in two ways. On one hand, the results of single laser decontamination can be enhanced by the subsequent placement of chlorhexidine chip into a periodontal pocket. Conversely, there is no added benefit of laser decontamination of a pocket prior to local delivery of chlorhexidine.

There were some limitations like study period was too short and study population was too less to come to a final conclusion and no microbial evaluation was done to evaluate the antimicrobial effect of both laser and chlorhexidine chip.

Within the limitations of the present study, the following conclusions may be derived chlorhexidine local delivery alone or in combination with diode laser decontamination is effective in improving oral hygiene, reducing gingival inflammation, 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. Adjunctive use of a single application of diode laser decontamination has no significant effect on the clinical periodontal parameters over the results achieved by scaling and root planing.

Further studies employing larger sample size with multiple laser applications are warranted to substantiate the role of laser decontamination of periodontal pockets as an adjunct to scaling and root planing in the management of chronic periodontitis.