March, 2010
Efficacy of Chlorhexidine Varnish on Streptococcus Mutans in Plaque
A randomized clinical trial evaluating the efficacy of Chlorhexidine varnish on Streptococcus mutans in plaque and the gingival status in patients undergoing orthodontic treatment.
Authors : Dr. Rahamathulla Khan M.D.S and Dr. Verdine Virginia Antony M.D.S
ABSTRACT
Introduction: Orthodontic appliances often modify the oral environment as they provide good retention sites for oral microorganisms. Plaque increases around bands and brackets, the composition of the oral flora changes, and cleaning becomes more difficult for the patient. As a result, gingival inflammation and enamel decalcification could result around fixed appliances if proper preventive programs are not followed.
Objective: The purpose of this double-blind, randomized controlled trial was to evaluate the efficacy of chlorhexidine-1% thymol varnish (Cervitec) on the Gingival status and Streptococcus mutans count in patients with fixed orthodontic appliances.
Method: A split mouth technique was followed on thirty patients in the age group of 13-18years, evaluating the efficacy of a single application of the test varnish on two randomly allotted quadrants along with a placebo on the other two quadrants. Evaluation of the parameters namely: plaque index, Gingival index, bleeding index and Streptococcus mutans counts were recorded at baseline, 1 month and 3 months respectively.
Results: A single application of the test varnish significantly reduced the Streptococcus mutans count in the first month compared to the placebo group. The Gingival health was significantly improved by the test varnish at 1 and 3 months evaluation compared to that of the placebo group.
Conclusion: This study proved that sustained release devices like chlorhexidine varnishes are a viable option for orthodontic patients.
INTRODUCTION:
Orthodontic treatment with fixed appliances modifies the oral environment. Plaque increases around bands and brackets, the composition of the oral flora changes, and cleaning becomes more difficult for the patient [1]. It has also been recognized that the number of Streptococcus mutans (sm) increase in the oral cavity after orthodontic bonding. As a result, gingival inflammation and enamel decalcification around fixed appliances can result without preventive programs. With the intention to resolve these issues, the idea of a chlorhexidine varnish was introduced. The improvement is demonstrated in its precise application to caries risk sites – around brackets, fissures and adjacent sites eliminating the adverse effect to oral mucosa. [1,2]
Chlorhexidine is a bis-biguanide agent with antibacterial properties, having a special affinity for oral structures. The effect of chlorhexidine in inhibiting plaque formation and reducing bacteria in the oral cavity, including streptococci, which are associated with the development of carious lesions, is well established in the literature. [3,4,5] Chlorhexidine is widely used in clinical dentistry in various vehicles such as gels, sprays, varnishes, mouthwashes, chips, chewing gums, and dentifrices. [5,6,7]
Thus, the aim of this study was to evaluate the efficacy of 1% chlorhexidine -1% thymol varnish (Cervitec) on the Streptococcus mutans count and the Gingival health in patients with fixed orthodontic appliances.
METHODOLOGY:
The patients undergoing fixed orthodontic treatment in the Department of Orthodontics, Sirt, Libya participated in this study. A total of 30 patients selected randomly, including both males and females in the age group of 13 – 18 years were considered. Patients participated in the study after signing an informed consent.
Clinical trial design:
The design of this study was double-blind, characterizing a randomized controlled trial. To recruit the volunteers, 50 patients attending the orthodontic clinic at Sirt Dental School and hospital, Libya, were informed about the study. Of these, 34 patients had an interest in participating and left their phone number for contact. They were screened by phone and invited to participate in a meeting to explain the 3-month clinical study. From these, 30 fulfilled the criteria to participate in the trial. The aim of the study was also described in a written information letter sent to the parents and participants.
The inclusion criteria were complete dentition up to the second molars, no detectable carious lesions and faulty restorations, good general health, and no pharmacotherapy for at least 3 months, no pregnancy, and non-smokers.
The exclusion criteria included the use of oral antimicrobials or antibiotics within the past 3 months, the presence of prosthodontic appliances, or significant systemic disease.
A split mouth technique was followed on the 30 volunteers with fixed orthodontic therapy evaluating the test varnish on two randomly allotted quadrants along with a placebo on the other two quadrants
At baseline (T0), 1month (T1) and 3 months (T2), clinical examinations were carried out. At the baseline screening, all subjects were between 13 and 18 years of age.
The following data were blindly recorded:
- Extrinsic stain of the dental enamel by area (SI)
- Criteria for calculus by the simplified oral hygiene index (CI)
- Gingival index (GI)
- Bleeding index (BI) and
- Plaque index (PI).
The counts of the microorganism were evaluated at 3stages: At baseline (T0), 1month (T1) and 3 months (T2).
Prior to the study, the supraGingival stain, plaque, and calculus were removed. The subjects were requested to refrain from having scaling and polishing during the 3-month study period. However, they were advised that, if tooth staining became unacceptable, they could ask the study dentist to remove the staining by polishing.
Before baseline examination, the subjects refrained from all oral hygiene measures for 24h. At baseline, the Streptococcus mutans levels in plaque and clinical parameters namely Calculus index, Gingival index, Bleeding index and Plaque index were recorded at the test sites. [8]
The plaque Streptococcus mutans scores were determined with the site-specific modified Strip-mutans® technique (Orion Diagnostica, Finland). [8,9,10]
The number of colony-forming units (CFU) with characteristic morphology was screened and scored 0–3. The evaluation was blinded.
Scores were as follows:
- 0 indicates no CFU (ms below detection level).
- 1 indicates 1–10 CFU, corresponding to approximately <104–105 CFU
- 2 indicates 10–100 CFU, corresponding to approximately105–106 CFU
- 3 indicates >100 CFU, corresponding to >106 CFU.
Selected teeth for plaque sampling were isolated with cotton rolls and dried. A small sterile brush was carefully brushed on the sites around the brackets of eight teeth (teeth 11, 14, 22, 25, 31, 34, 42, and 45) in each of the thirty patients.
This means that a total of 240 sites were evaluated. In case of an extracted premolar, the adjacent premolar was evaluated.
All brackets were placed with etching gel, bonding material, and light curing composite. Sampled plaque was immediately spread on the roughened side of the plastic strip from the Strip-mutans® kit (Orion Diagnostica, Finland). The strips were allowed to dry for 5 minutes at room temperature and were then incubated for 48 hours in a liquid medium. The composition of the medium was similar to the composition of mitis salivarius agar, with a sucrose concentration increased to 30%. Addition of a bacitracin disc from the kit results in a final concentration of 0.36 U of bacitracin per ml of medium. Additionally, a saliva Strip-mutans test was performed for each participant and evaluated. After 48 hours cultivation in the liquid medium, the scores of Streptococcus mutans in plaque were recorded with the aid of a stereomicroscope with 10-25X magnification.
The 30 subjects fulfilling the inclusion criteria were treated with Cervitec® which was applied with a small brush in a thin layer around each bracket and allowed to set for 30 seconds.
The volunteers returned to the clinic 4 and 12 weeks after the trial started, and the clinical indices at baseline were re-evaluated. At each visit, the volunteers were given oral hygiene instructions. At the end of the study, all volunteers were seen by the dentist, and all extrinsic stain, plaque, and supraGingival calculus were removed.
RESULTS:
The Plaque Index score in both the test and placebo site showed a statistically and highly significant (p<0.000) improvement over a duration of 12 weeks. The mean change in Plaque index at the test sites was 0.9000 + 0.2487 which was greater than that observed at the placebo site (1.3500 + 0.4617) (Table 1). This indicated a better performance by the test site compared to the control, with the varnish application site showing better results.
Table 1: Plaque Index
A statistically highly significant (p<0.000) reduction in Gingival Index was observed at both test and placebo sites over 12 weeks. A mean change of 0.7375 + 0.2361 at the test site indicated a higher reduction in the Gingival Index compared to the control site which showed a mean change of 1.3250 + 0.2308 over 12 weeks (Table 2).
Table 2: Gingival Index
A statistically highly significant reduction (p<0.000) in the calculus index and bleeding index was noted in both the test as well as the placebo groups; the Test site showing a greater significance when compared to control Site.
A statistically highly significant reduction (p<0.000) in the staining index was recorded at baseline and one month with a significant increase at the end of the study in the test site when compared to the control site.
In the microbial analysis, all microbiological measurements were recorded on a grading scale; four grades 0, 1, 2, and 3 are the possible values, which are called ties in the statistical literature. The statistical design used in our trial is a repeated measures design i.e., the same patients are repeatedly observed at several time intervals. This means that statistically significant differences are assumed when time profiles are not parallel to the x-axis.
The effect of Cervitec® application on Streptococcus mutans showed a mean decline in the MS count after one month of application when compared with baseline. Three months after application a slight increase of SM mean level was recognized but it did not reach the baseline value. The levels of Streptococcus mutans in saliva were significantly reduced after one month (p < 0.01). After twelve weeks Streptococcus mutans levels in saliva were given a relative increase. No significant suppression was found in the placebo group (p > 0.05) (Table 3).
Table 3: Mutans streptococci count
The sm scores were below detection level (score 0) in only 130 sites at the end of the 4-week period. After 12 weeks, sm counts were slightly increased. But, we could observe intra-individual differences. The degree of re-infection varied considerably between different patients. However, only 5 patients showed a distinct suppression of sm counts.
The results suggested that Cervitec varnish reduces salivary Streptococcus mutans levels and that the application should be repeated every 3 months to get antibacterial effect.
DISCUSSION
Chlorhexidine is the most thoroughly studied anti-plaque substance and it has good plaque-inhibiting properties with an immediate antibacterial effect and a prolonged effect on the oral flora. Many long-term clinical studies have also confirmed the good safety profile of chlorhexidine formulations. [3] However, reversible local side effects such as staining of teeth, impaired sense of taste, increased formation of supraGingival calculus, and occasionally mucous membrane irritation and desquamation are associated with prolonged use of chlorhexidine. [5] To a varying degree, these factors might adversely affect patient compliance.
Therefore, it would be ideal to incorporate chlorhexidine into a varnish, thus reducing its side effects but providing antiplaque benefit, and resulting anti-gingivitis benefit with no added discomfort for patients.
According to our study, after the chlorhexidine containing varnish treatment, the Gingival status showed a significant improvement with a stastically significant reduction in the Gingival index, plaque index and bleeding index at the control site. Thus, chlorhexidine varnish could be used as an adjunct to mechanical tooth cleaning in preventing gingivitis in patients undergoing treatment with fixed orthodontic appliances.
The microbilogical study showed that the levels of Streptococcus mutans in saliva were significantly reduced after one month (p < 0.01), after twelve weeks Streptococcus mutans levels in saliva were given a relative increase. The results suggested that Cervitec varnish reduces salivary Streptococcus mutans levels and that the application should be repeated every 3 months to get antibacterial effect.
Sustained release devices, like varnishes, reduce the numbers of Streptococcus mutans in a patient’s mouth to levels below detection for long periods, but their effectiveness in preventing and controlling caries needs to be assessed.
SUMMARY AND CONCLUSION
Fixed orthodontic appliances contribute to plaque accumulation and they are challenging in implementing proper oral hygiene. Metal brackets are meant to be responsible for lowering of the pH level and the demineralization of tooth hard tissue around their bases. It has been recognized that the number of Streptococcus mutans (SM) increase in the oral cavity after orthodontic bonding.
Due to the potential food traps caused by the placement of orthodontic appliances, gingivitis and periodontal destruction could occur. With the intention to resolve these issues, the idea of a chlorhexidine varnish was introduced. The improvement is demonstrated in its precise application to risk sites – around brackets, fissures and adjacent sites eliminating the adverse effect to oral mucosa. Varnishes are sustained release devices that have been introduced with an aim of maintaining an ideal drug concentration over long periods of time. Therefore it would be of great clinical benefit if a sustained release chemical agent could be used during the active phase of orthodontic treatment to reduce the bacterial plaque formation, thereby improving the Gingival condition and thereby reducing the incidence of caries and periodontal disease.
Hence this three month in-vivo study was carried out to investigate the efficacy of a single application of a commercially available Chlorhexidine varnish (Cervitec) against streptococcus mutans as well as its effect on Gingival health. Results indicated that a single application of the test varnish was capable of significantly reducing the Streptococcus mutans count in the first month when compared to the placebo group and this difference was stastically significant. The test varnish had no effect on Streptococcus mutans at the end of three months and there was no statically significant difference in the bacterial counts between the two groups.
Gingival health was significantly improved by the test varnish both at one and three months evaluation, in comparison with the placebo group, thus indicating an efficacy in maintaining Gingival health for a long period of time.
This study proved that sustained release devices like Chlorhexidine varnishes are a viable option for orthodontic patients-improving the Gingival health as well as reducing the Streptococcus mutans counts preventing enamel demineralisation.
Side effects that prevent the long-term use of Chlorhexidine mouth rinses are not seen in this delivery system. Thus, this new therapeutic agent in the orthodontists armamentarium is an effective tool in reducing Streptococcus mutans and maintaining the Gingival health.
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Contributed by:
Dr. Rahamathulla Khan M.D.S
Head of Department, Department of Orthodontics, Dental Faculty, Al-Tahadi University, Sirte, Libya
Dr. Verdine Virginia Antony M.D.S
Department of Periodontics, Dental Faculty, 7th October University, Misurata, Libya
