Effect of controlled-release Periochip™ on clinical and microbiological parameters in patients of chronic periodontitis.

BACKGROUND: The aim of the present study was to evaluate and compare the clinical and microbiological effectiveness of Periochip™ as an adjunct to scaling and root planing (SRP) with SRP alone in patients with chronic periodontitis.
MATERIALS AND METHODS: This randomized, split mouth, 3-month clinical and microbiological trial included 30 sites in 15 patients aged 30-50 years diagnosed with chronic periodontitis. In each patient, two bilateral pockets probing 5-7 mm were randomly assigned to test and control groups. The test group received SRP plus Periochip™, whereas the control group received SRP alone. Clinical indices and anaerobic culture analysis was done at baseline, 1 month, and 3 months interval. Total bacterial count and analysis of four major periodontopathogenic bacteria Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Aggregatibacter actinomycetemcomitans (Aa), and Fusobacterium nucleatum (Fn) was done.
RESULTS: Significant improvement was obtained in all clinical variables in the test group as compared to the control group over the study period. Total colony counts were significantly reduced in the test group as compared to control over the period of time. At baseline Aa was recovered from 4 test group sites and 5 control group sites, Pg from 15 test group and 14 control group sites, Pi from 5 test group and 2 control group sites, Fn from 7 test and 7 control group sites. At 3 months, Aa was recovered from 1 test group and 4 control group sites, Pg from 4 test group and 8 control group sites, Pi from 1 test group and 1 control group site, Fn from 3 test and 4 control group sites.
CONCLUSION: Periochip™ placement as an adjunct to SRP, showed promising results, when compared to SRP alone. Healthy microflora can be maintained for a longer period of time and delay in the repopulation by periodontopathic microorganisms was observed.

RCT Entities:   Population Interventions Outcomes

INTRODUCTION

Chronic periodontitis is an infectious disease resulting in inflammation within the supporting tissues of the teeth, progressive attachment loss, and bone loss and is characterized by periodontal pocket formation and/or recession of the gingiva.[1] Elevated proportions of some subgingival microbial species have been associated with destructive periodontal disease activity like Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Tannerella forsythia, Peptostreptococcous micros, Campylobacter rectus, Eiknella corrodens, Fusobacterium nucleatum (Fn), Eubacterium species, Treponema denticola, Selenomonas species, Beta–hemolytic streptococci, a variety of enteric rods and pseudomonas, Enterococci, Staphylococci, and possibly yeasts.[2345] It is important to keep the pathogenic microflora of the pocket suppressed in order to maintain health of the periodontal tissues.[67] The most widely used approach has been scaling and root planing (SRP) that effectively decreases the microbial load but recolonization of the same can occur as early as 60 days after SRP.[26891011]

In addition to mechanical treatment, the use of antimicrobial agents, both systemic and topical, has been increasing because of the realization that periodontal disease is not merely an overgrowth of bacteria, but also a shift in bacterial species.[12] Systemic administration of drugs has been useful in treating periodontal pockets, but it involves a relatively high dose with repeated intake over a prolonged period of time to achieve the required inhibitory concentrations in the sulcular fluid. This increases the chances of development of resistance, alteration of commensal flora, and increased potential for adverse effects.[1314151617] Local administrations, therefore, provide a useful answer to these problems and are developed to deliver therapeutic levels of antibacterial agents directly into the pocket with no systemic side effects; however, the important factor in the success of this treatment is the ability to control and to prolong the release rate of the therapeutic agent from the device.[2]

Periochip™ is the controlled release subgingival delivery of chlorhexidine, developed by Perio Products Ltd, Jerusalem, Israel. It is an orange brown rectangular chip, rounded at one end. It measures 5 mm × 4 mm × 0.3 mm, weighs about 7.4 mg and contains 2.5 mg of chlorhexidine gluconate, which is incorporated in a biodegradable matrix of hydrolyzed gelatin cross linked with glutaraldehyde. The matrix also contains glycerin and purified water and should be stored under refrigerated condition at 2-8° C. It was first introduced into U.S. dental market in 1998. Room temperature Periochip, which provides the added benefit of being easy to store, and simple to use was introduced in 2002, by Dexcel Pharma Technologies, Jerusalem, Israel. It is available in boxes of 2 strips with 10 chips each. Shelf life is 2 years. Each chip is individually packed in a separate compartment of an aluminum blister pack as shown in Figure 1. A two-phase release profile of chlorhexidine from the chip has been observed. An initial burst of unbound chlorhexidine release was found over the first 24 to 48 hours during which 40% of the chlorhexidine was released into a buffer solution containing collagenase. Thereafter, a slower release of the remaining chlorhexidine, bound to the matrix, occurred until complete biodegradation of the chip was completed.[181920] Peak average concentration of chlorhexidine in gingival crevicular fluid has been reported to be 2007 μg/ml after 2 hours, followed by 1300-1900 μg/ml for the next 96 hours, with the releasing being over 1250 μg/ml for the first 4 days, followed by a gradual decline with average concentration greater than 125 μg/ml for 8 days and it has been shown that chlorhexidine at >125 μg/ml can inhibit 99% of the cultivable bacteria, on average.[2122]

Figure 1

Box containing Periochip with each chip packed in a separate compartment of aluminum blister pack

In the present study, an attempt was made to know the efficacy of Periochip™, placed in the periodontal pocket post SRP, on clinical parameters and in suppressing the pathogenic anaerobic microflora when compared with SRP alone.

MATERIALS AND METHODS

Study patients

The study was a randomized, split mouth, 3-month clinical and microbiological trial in which 30 sites from 15 subjects (8 males and 7 females) with chronic periodontitis were selected, with age ranging from 30 to 50 years. Patient selection criteria included the following.

Inclusion criteria

Patients with chronic periodontitis,[23] with the presence of at least 2 bilateral periodontal pockets with 5-7 mm probing depth

Negative history of any systemic disease

No allergy to chlorhexidine

Non-tobacco users.

Exclusion criteria

Pregnant or lactating mothers

Patients suffering from condition requiring antibiotics prior to dental procedures or currently using antibiotics, anticoagulants, steroids, or any other medication which could alter the oral microflora were excluded

Mobile, carious, endodontically treated teeth were excluded.

Periodontal treatment and subgingival plaque collection

An informed written consent was obtained from all selected patients. Gingival index (GI)[24] and plaque index (PI)[25] were measured and recorded as baseline data. Acrylic stents, with position of the experimental site marked by a vertical groove, was used as a reference point to determine the exact site of measurement to ensure reproducibility of the examinations. The study sites were then randomly assigned to one of the two treatments i.e. test site treated with SRP followed by placement of Periochip™ and control site treated with SRP only. Supragingival scaling was done in all patients to prevent contamination of the subgingival plaque samples.

The baseline plaque samples were obtained from the depth of the periodontal pocket using a sterilized Gracey curette from both control and test site and then placed in an air tight thioglycolate broth transport media supplemented with Hemin and vitamin K in a 5 ml test tube. The collected plaque samples were immediately sent to lab for culture test of four anaerobes including Pg, Pi, Aa and Fn.

Then subgingival SRP was performed in both test and control groups. Probing depth (PD) and relative attachment level (RAL) for both control and test sites were recorded using the UNC-15 probe with stent and value obtained was taken as a baseline value. In the test group sites, before inserting the chip, the area was dried with the cotton rolls. The flat end of the chlorhexidine chip (Periochip™) was grasped with a tweezer and the rounded end of the chip was pressed apically into the test site, so that the chip rested subgingivally at the base of the pocket and making sure that it was not exposed as shown in Figure 2. Then the periodontal pack was placed. The patients were then instructed to continue with regular oral hygiene measures, except for the use of chemotherapeutic mouth rinses and oral irrigation devices. All patients were recalled after 7 days for pack removal and evaluated for any clinical signs of inflammatory response.

Figure 2

Placement of Periochip in a periodontal pocket

All clinical parameters and subgingival plaque collection was repeated after 1 month and 3 months.

Anaerobic culture

The sample collected in Thioglycolate broth transport media was transported to the lab within 48 hours of collection. The sample was then well mixed by vortexing and 10 ml of the sample was inoculated on to the following media to see the growth of following organisms:

Dentaid media (yeast extract, sodium fumerate, sodium formate, and vancomycin) for Aa

Supplemented blood agar for pigmented anaerobes – Pg, Pi, Fn.

These two above media were incubated anaerobically in a modified gas pack jar for 5 days.

The identification of the organisms was carried out by colony characters, pigmentation, gram stain appearance, and certain standard key biochemical reaction.

The quantity of colonies were carried out by counting the number of each type of colonies with the magnifying glass and multiplying by the dilution factor, i.e. 200 and expressed as colony forming units per ml (cfu/ml). The total bacterial count and number of sites positive for each microbial species over time (at baseline, 1 month, and 3 months) were recorded.

Statistical analysis

The statistical analysis was done using SPSS version 15.0 statistical analysis software. The values were represented in number (%) and mean ± standard deviation (SD). The intragroup comparison was done using Wilcoxon's signed rank test and the intergroup comparison was done using the Mann-Whitney U test. Cross tabulation was done using fisher-exact test. As the sample size was 30, before starting the data analysis, the distribution was checked for normality using the Kolmogorov-Smirnov test which yielded an asymmetric and non-normal distribution for all the four clinical parameters in both the groups. Considering the size of the sample and asymmetric distribution, a non-parametric analytical plan was adopted.

RESULTS

Intragroup evaluation at different time intervals in the test group showed that all the changes were significant statistically at all the time intervals (P < 0.05), as shown in Graph 1. Evaluation of change at different time intervals in the control group also showed that the changes were significant statistically at all the time intervals (P < 0.05), except for PI measured from 1 month to 3 months follow up (P = 0.763) as shown in Graph 2. A comparison of the mean change in clinical parameters between baseline and 1 month revealed a statistically significant intergroup difference for all the parameters with the test group showing significantly higher change as compared to the control group (P < 0.05) as shown in Table 1.

Graph 1

Evaluation of change in clinical parameters between different time intervals in the test group

Graph 2

Evaluation of change in clinical parameters between different time intervals in the control group

Table 1

Comparison of change in clinical parameters in two groups between baseline and 1 month

A comparison of the mean change in clinical parameters between baseline and 3 months revealed a statistically significant intergroup difference for all the parameters with the test group showing significantly higher change as compared to the control group (P < 0.001) as shown in Table 2.

Table 2

Comparison of change in clinical parameters in two groups between baseline and 3 months

A comparison of the mean change in clinical parameters between 1 month and 3 months revealed a statistically significant intergroup difference for all the parameters except PD with the test group showing significantly higher change as compared to the control group (P < 0.001). For PD, the mean change during the period was equal in both the groups (P = 0.967) as shown in Table 3.

Table 3

Comparison of change in clinical parameters in two groups between 1 month and 3 months

Microbiological parameters included evaluation of reduction in total bacterial colony count and evaluating the reduction of four mentioned periodontal pathogens at baseline, 1 month, and 3 months follow-up visits. An intergroup comparison of mean changes in total bacterial colony counts revealed no significant difference between two groups at baseline and 1 month intervals; however, the difference between two groups was significant statistically at 3 months (P < 0.001). At both the follow-up intervals, an intragroup comparison revealed a statistically significant reduction in both the groups, with the test group showing lower mean values as compared to the control group as shown in Table 4.

Table 4

Comparison of mean total colony count/ml in two groups at different time intervals

Aa was present in 4 out of 15 test group sites at baseline and at 1 month only 2 samples were positive and at 3 months 1 sample was positive out of 15. Similarly, for the control group, 5 sites were positive at baseline that reduced to only 2 samples at 1 month and 4 samples out of 15 at 3 months as shown in Table 5.

Table 5

Distribution of Aa organism at different intervals in control and test sites

Pi was present in 5 out of 15 test group samples at baseline which reduced to 0 samples at 1 month and 1 sample at 3 months. Similarly, in the control group, 2 samples out of 15 were positive at baseline and 2 samples were positive at 1 month that reduced to 1 sample after 3 months as shown in Table 6.

Table 6

Distribution of Pi organism at different intervals in control and test sites

Pg was present in all 15 test group samples at baseline and at 1 month 5 out of 15 sites were positive and at 3 months only 4 samples were positive. Similarly, in the control group, 14 sites out of 15 were positive at baseline and at 1 month 7 samples were positive and at 3 months 8 samples were positive out of 15 as shown in Table 7.

Table 7

Distribution of Pg organism at different intervals in control and test sites

Fn was present in 7 out of 15 test group samples at baseline that reduced to 4 samples at 1 month and only 3 samples were positive at 3 months. Similarly, in the control group, 7 samples out of 15 were positive at baseline and at 1 month 6 samples were positive and at 3 months 4 out of 15 samples were positive as shown in Table 8.

Table 8

Distribution of Fn organism at different intervals in control and test sites

DISCUSSION

In the present study, the efficacy of chlorhexidine-containing local drug delivery system (Periochip™) was evaluated over SRP alone for a period of 3 months. The clinical parameters were recorded at 1 month as the bacterial flora is supposedly said to return to pretreatment patterns after 3-6 weeks of SRP.[62627] The 3-month interval was chosen because the effects of locally delivered chlorhexidine has been shown to be evident for 11 weeks after administration and also 3 months corresponds to the typical recall interval for patients after periodontal treatment.[102829]

Significant reduction in the GI was seen in the test group and the control group from baseline to 3 months with the test group showing significantly higher reduction (0.80 ± 0.19) as compared to the control group (0.33 ± 0.24) (P < 0.001). Similarly, a mean reduction in PI was significantly higher in the test group (1.53 ± 0.52) as compared to the control group (0.67 ± 0.41) (P < 0.001) as shown in Table 2. These findings are in accordance with the results obtained in studies conducted by Stabholz et al.,[10] Soskolne et al.,[28] Jeffcoat et al.,[29] Heasman et al.,[30] Azmak et al.,[31] Mizrak et al.[32] However, there was not much reduction in PI from 1 month to 3 months (P = 0.763 i.e. >0.05) in the control group with few sites having greater PI at 3 months than 1 month follow-up visit. A single session of SRP is capable of disturbing the proportions of certain bacterial forms in the subgingival periodontal flora and that it may require approximately 9-11 weeks for the proportions to return to baseline values that may also enhance plaque formation.[1130] There was a significant reduction in PD in both test group and control group from baseline to 1 month, 1 month to 3 months, and from baseline to 3 months when intragroup comparisons were done and also from baseline to 1 month and baseline to 3 months when intergroup comparisons were done clearly depicting a significantly higher change in the test group as compared to the control group. However, the intergroup comparison for PD reduction from 1 month to 3 months follow-up visit showed that the mean change during the period was equal in both the groups (P = 0.967). This is in accordance with the studies conducted by Stabholz et al.,[10] Jeffcoat et al.,[29] and Heasman et al.[30] RAL showed significant improvement for both intragroup and intergroup comparisons between baseline and 1 month, 1 month and 3 months, and from baseline to 3 months. This was similar to the results obtained by Grisi et al.[33] and Paolantonio et al.[34]

Higher improvement in clinical parameters in the test group can be attributed to chlorhexidine, which is known to inhibit microbial proteases from potent periodontal pathogens, which play a key role in the destruction of periodontal tissues during the progression of periodontal disease. This is in accordance with the results obtained by Grisi et al.[33] and Paolantonio et al.[34] Also, prostaglandin E2 is an immunoactive host produced agent, the release of which is dependent on the availability of arachidonic acid from which it is a metabolite can induce pathologic tissue alteration. The use of chlorhexidine chip has shown a reduction in PGE2 levels which might be a causative factor for improvement of clinical parameters in accordance with Mizrak et al.[32]

Total bacterial count changes were calculated at different intervals for both test and control groups. No significant difference between test group and control group was observed at baseline and 1 month intervals; however, the intragroup change as compared to baseline was statistically significant at both 1 month and 3 months. Moreover, at 3 months, the mean reduction in total bacterial count in test group was significantly higher than control group (P < 0.001). The results of the present study are in accordance with the results obtained by Paolantonio et al.,[34] but are not in agreement to results obtained by Daneshmand et al.,[35] who did not obtain any statistical difference in total colony counts between the two treatment groups at any time point during the study.

The percentage distribution of 4 periodontal pathogens i.e. Pg, Aa, Pi and Fn species were assessed at different intervals in both control and test group showing greater reduction in test group as compared to control over a period of 3-months, although the intergroup comparison revealed statistically non significant (NS) results.

Previous studies have demonstrated that mechanical treatment i.e. SRP is effective in altering the flora.[3637] The most critical factor regarding treatment with any antimicrobial drug may be the length of time during which microorganisms are exposed to drug. The antimicrobial effects of Periochip™ are sustained for up to 11 weeks following 6-9 day exposure.[10] The fact that bacteria are found within the depth of the epithelial lining as well as in the connective tissues of the pocket wall might initially protect them from chlorhexidine, but natural shedding of the epithelium would eventually expose the protected bacteria to drug. Thus, the use of Periochip™ can delay the repopulation of bacteria,[22] as it reduces the virulence of certain periodontal pathogens by inhibiting their proteolytic and glycosidic activities as these activities aid in producing potential virulence factors.[38] However, in vivo, the serum proteins of the subgingival environment may reduce chlorhexidine antimicrobial activity by reducing its substantivity.[2133] Moreover, there is some evidence that Pg releases vesicles that bind to and inactivate chlorhexidine, protecting themselves and other bacteria from the agent, which could have interfered with the microbiological results of the present study.[3940]

CONCLUSION

The use of local delivery systems with antimicrobial agents does not replace the need for thorough SRP, which remains the most important and the primary treatment modality.

Local drug delivery with the use of Periochip™ along with SRP is a simple and non invasive technique that consists of sufficient quantity of the drug to provide adequate therapeutic level, as a beneficial adjunctive treatment modality to enhance periodontal health. It also reduces and delays the recurrence of periodontal pathogens in periodontal pockets.