Efficacy of 0.2% tempered chlorhexidine as a pre-procedural mouth rinse: A clinical study.

OBJECTIVE: Our objective was to determine the efficacy of pre-procedural rinsing with chlorhexidine in reducing bacterial aerosol contamination during use of ultrasonic scaler and comparing the efficacy of water, non-tempered chlorhexidine and tempered chlorhexidine in reducing bacterial count in aerosols when used as a pre-procedural rinse.
MATERIALS AND METHODS: The study was designed to include 30 systemically healthy patients in different age groups. The patients were divided randomly into 3 groups (I, II, III) of 10 patients each to be administered with sterile water, non tempered chlorhexidine and tempered chlorhexidine, respectively, as a pre-procedural rinse. The aerosol produced by the ultrasonic unit was collected at 3° clock, 6° clock and 12° clock positions on blood agar plates within a range of 4 feet in all the three groups. The blood agar plates were incubated for 48 hours and the total number of colony forming units (CFUs) were counted and statistically analyzed.
RESULTS: The results showed that CFU in group III and group II were significantly reduced when compared to group I with F=1084.92, P<0.001 (ANOVA). Also, CFU in group III was significantly reduced when compared to group II with P<0.001.
CONCLUSIONS: Pre-procedural rinse can significantly reduce the viable microbial content of dental aerosols and tempered chlorhexidine was more effective than non-tempered chlorhexidine.

RCT Entities:   Population Interventions Outcomes

INTRODUCTION

Dental surgeons and oral health care workers are daily exposed to a variety of microorganisms including bacteria, viruses, protozoan through the patients and the working environment. In absence of proper preventive measures, the health care professionals are at high risk of exposure to various infectious diseases which may be air borne or vector borne.

Introduction of ultrasound in the field of dentistry by Catuna (1953)[1] for purpose of cutting teeth, a new direction was seen. This work was further carried forward,[23] who showed that ultrasound in the form of ultrasonic can be beneficial to remove deposits from the teeth and showed similar results when compared with hand scaling instruments. But as everything comes with its own sets of merits and demerits, ultrasonic scalers were no exception. The aerosol produced by the ultrasonic's heavily contaminated with bacteria and hence a potential threat to the operator, dental auxiliary and the patients.[4] A marked increase in the airborne organisms was demonstrated in the samples collected from dental clinics where ultrasonic scalers were in use. A considerable microbial challenge was shown in the immediate vicinity of the individual patients who received the treatment with ultrasonic scalers (Holbrook et al.).[5] It was also found that the microorganisms could survive in the aerosol produced for as long as 6 days[26] There appeared to be two distinct patterns of bacterial contamination to which the operator as well as auxiliary staff is exposed. Those were visible ballistic splatter of large particles (≥100 μ) and floating particle contamination (≤100 μ).[78]

Several methods have been tried to reduce aerosol contamination in the dental office like using high vacuum suction, patient positioning, use of rubber dams, and pre-procedural antibacterial mouth rinses.

Use of antibacterial mouthwash as a means of reducing the bacterial aerosol was investigated.[29] In their study, they found the use of cetyl pyridium chloride in concentration of 1:2000 showed a reduction of 90% in the mean number of bacteria produced during high speed instrumentation. Likewise, Bonesvoll (1974),[10] investigated the influence of concentration, time, temperature, and pH of 0.2% chlohexidine rinse in the oral cavity. The investigation showed no significant increase in retention of the parent chemical in the oral cavity on altering the temperature from 22°C to 60°C. Though the rate of chemical reaction was said to have increased with increase in temperature,[2] it was shown that tempered chlohexidine has more antimicrobial effect than the non-tempered counterpart. Hence, with the conflicting literature on the efficacy of tempered chlorhexidine, an attempt was made in the present study to compare and determine the effect of temperature in reducing the bacterial load of the aerosols produced by the ultrasonic units.

MATERIALS AND METHODS

This was an in vivo study conducted in the department of periodontics, Dr. Syamala Reddy dental college, hospital and research centre, Bangalore, Karnataka, India. This study was conducted on 30 subjects, who visited the department, and there was no age and sex criterion in selecting the subjects. They were informed about the study and their inclusion was purely voluntary. Patients with the history of treatment for moderate to severe periodontitis in past six months, systemic diseases, and who were on systemic antibiotics were excluded from the study.

The above mentioned 30 subjects were randomly distributed into groups I-III of ten subjects each [Figure 1].

Figure 1

Diagramatic depiction of the study design

Group I: This group comprised of 10 patients, who rinsed with sterile water for 60 seconds.

Group II: This group comprised of 10 patients, who rinsed with 0.2% of non-tempered chlorhexidine mouthwash for 60 seconds.

Group III: This group comprised of 10 patients, who rinsed with 0.2% of tempered chlorhexidine mouthwash for 60 seconds.

The subjects included in the study were instructed not to use any chemical plaque control measures from 24 hours before the study. The tempered chlorhexidine used in the study was made by placing of chlorhexidine solution in thermostatically regulated water bath whose temperature was kept constant at 47°C.[2]

Before the start of the professional treatment with ultrasonic scalers, a pre-procedural collection of aerosol was done at a distance of 4 feet at 3, 6 and 12 ‘O’ clock positions, respectively, in all the three groups. Then the patients were asked to rinse with sterile water, 0.2% chlorhexidine, and 0.2% of tempered chlorhexidine in the respective groups for 60 seconds. Later, professional ultrasonic scaling was done by qualified dental professionals. In the mean time, while the patients were undergoing treatment the aerosols were collected by the previously mentioned criteria on blood agar plates placed at a distance of 4 feet (Belting 1964). The blood agar plates were incubated for 48 hours and were inspected for the number of bacterial colony forming units (CFUs) [Figure 2]. All the samples on the blood agar plate were collected by the same investigator. In the present study, we were only assessing the number of bacteria in the aerosol and not the type of bacteria, and the collected data was statistically analyzed. Below is diagrammatic depiction of study design [Figure 1].

Figure 2

Microbial colonies formed on an agar plate

RESULTS

Table 1 shows the results of all three groups. In group I, there was no statistically significant difference between the pre- and post-rinse with sterile water [Figures 3 and 4]. Whereas in groups II and III, statistically significant (P<0.001) difference in values of CFUs was seen in Figures 2 and 5.

Table 1

Comparison of rinse CFU between three groups (Mean±SD)

Figure 3

CFUs in group I (pre-rinse)

Figure 4

CFUs in group I (post-rinse)

Figure 5

CFUs in group II (post-rinse)

CFUs in groups II and III were significantly reduced when compared to group I [Figures 2 and 6] (F=1084.92, P<0.001), using ANOVA as the statistical method. Also it was seen that CFU in group III was statistically less (P<0.001) than group II. The results obtained were plotted onto graphs with bar diagram and scatter diagrams as shown in Figures 7 and 8.

Figure 6

CFUs in group III (post-rinse)

Figure 7

Bar diagram showing CFU's

Figure 8

Scatter diagram showing CFU's

In the present study, following pre-procedural rinsing for 1 min with tempered solution, the increase in bacterial kill rate was 90%, and the result was statistically significant (P<0.01)

DISCUSSION

Periodontitis is a multifactorial disease which results in the breakdown of the supporting apparatus of the dentition. Though the etiology is said to be multifactorial, the dental plaque is still considered to be the prime etiology. Dental plaque in turn is an assembly of various bacterial and non-bacterial microorganisms in a gelatinous matrix which show the property of dispersal or seeding voluntarily or when mechanically acted upon through the pressure of food, friction of soft tissues or dislodgement by the ultrasonic devices. Hence, the aerosols produced by the ultrasonic devices are heavily contaminated by these microorganisms which pose a serious health threat to the clinician and his surrounding in the form of systemic conditions like common cold, influenza, tuberculosis, HBV, HIV, legionellosis.[11-13] As the pathogens show a high probability of bypassing the host defence, thus a need of an adjunct therapy in the form of chemical plaque control to reduce the bacterial load in the aerosol is often warranted.

Though there was a ray of hope seen with the invention of vaccines for periodontal disease, but the failure of the vaccines to clear the clinical trials has raised doubts. So the best line of action is prevention of the disease causing entity and thereby disease itself. Chlorhexidine 0.2% was the first clinically effective and demonstrated mouthwash that inhibited supragingival plaque formation (Loe, Schiott et al and Addy et al and Santos et al)[14-18] and hence the development of chronic gingivitis[19] due to the broad spectrum antimicrobial activity of chlorhexidine which encompassed gram positive organisms, gram negative organisms, yeasts, dermatophytes, and some lipophilic viruses. Apart from the broad antimicrobial spectra it covers, chlorhexidine has a good substantivity too and that is why it is aptly recognized as the Gold standard for chemical plaque control.[2620] investigated the influence of concentration, time, temperature, and pH on the retention of chlorhexidine in the oral cavity after rinsing and no significant increase in retention was recorded by increase of temperature from 22°C to 60°C (Bonesvoll et al. 1974).[10] However, increasing the temperature does increase the rate at which the chemical reaction takes place as determined,[2] in his thermodynamic treatises. It is apparent that the observed effect is not solely due to the physical parameter of “temperature”. Storing of 0.2% of chlorhexidine at higher temperatures and for longer periods of time increases levels of contamination with toxic compounds like p-chloroaniline, and so in the present study, freshly prepared 0.2% chlorhexidine solutions were used which was heated to a temperature of 47°C in a temperature regulated water bath (Kohlbecker 1989).

This temperature, 47°C, was particularly selected as the literature suggests that this temperature is readily tolerable by the oral structures and does not alter the vitality of the pulpal tissues (Konig et al 2002). The result of the present study are in line with previous studies which show that the increase in temperature of 0.2% chlorhexidine showed significant bacterial reduction in dental aerosols when compared to that of non-tempered chlorhexidine and sterile water [Table 1, Group 2].

Studies have shown that that ultrasonic scaling in conjunction with various plaque control agents used as a pre-procedural rinse have been found to be more effective in reducing bacterial loads when compared with distilled water or saline.[21]

The adjuvant use of plaque control agents in our study was also supported by Litskym, et al[9] where use of 1:2000 cetyl pyiridinium chloride showed a significant reduction in the bacterial count in the aerosol produced by high speed dental hand pieces.

In agreement to our study, another study[22] compared chlorhexidine gluconate, essential oils, and water; the results indicated higher reduction in the bacterial counts achieved with the chlorhexidine gluconate solution.

In contrary to our study, a study[23] comparing the efficacy of aerosol reduction devices (ARD) with 0.12% chlorhexidine solution as a pre-procedural rinse demonstrated that the aerosol reduction suction device was better than the 0.12% chlorhexidine and distilled water in reducing the bacterial aerosol produced. Also the combination of aerosol reduction device and 0.12% chlorhexidine did not improve the results further.

The results of this study confirm that raising the temperature of chlorhexidine can increase its efficacy though, further clinical investigations will be required to determine the extent to which the temperature has to be raised to prevent development of gingivitis, and associated side effects such as discoloration, and disturbances with the sense of taste according to Flotra et al. 1971.[92425]

This study supports the other studies using chlorhexidine by demonstrating the excellent antimicrobial effects. Also, it puts forth the effectiveness of tempered chlorhexidine over the conventional usage of 0.2 % chlorhexidine as a pre-procedural rinse. Yet why it is being used by clinicians on a routine basis is still an enigma. The main rational explanation behind it seems to be the taste of the mouth rinse which could be objectionable to many. Another reason might be the cost factor. Nevertheless, the enormous benefits associated should be positively enforced into the patient to gain his trust and compliance.

Future trend: The use of tempered chlorhexidine in water jets could be new beginning in the direction of personally administered plaque control. The future research should thus be aimed in the direction of developing home care appliances which are simple to use and at the same time are equally efficacious and demand less patient compliance.

CONCLUSIONS

In the present study conducted, we found that chlorhexidine had a significant effect as an antimicrobial pre-procedural mouth rinse in reducing the number of CFUs in the aerosol produced by the ultrasonic scaling units. Also, though both the tempered and non-tempered forms of 0.2% were effective in reducing the bacterial load in the aerosol, the tempered chlorhexidine had a definite edge. Though the above results show a strong evidence for mouth rinsing before any dental procedures, yet very few clinicians follow this protocol. The implication of this procedure depends on the professional understanding and realizing the protective benefits in reducing the spread of micro organisms from their patient's mouth.

Thus, it can be concluded from the above study that pre-procedural rinse can significantly reduce the viable microbial content of dental aerosols and the tempered chlorhexidine was more effective when compared to non-tempered chlorhexidine in reducing the CFUs in the aerosol produced. When compared to sterile water, both were found superior and thus at least one of them should be used as pre-procedural rinse to keep the count of deadly colony forming units to bare normal.