EVALUATION OF AEROSOL CONTAMINATION DURING ULTRASONIC SCALING AND ROOT PLANING

Abstract :

Background:
Aerosol production is common with various dental and medical procedures. Aerosol production during various dental procedures like cavity cutting and scaling is a potential source of infection. Cross-infection through aerosol is a major source of infection to both medically compromised as well as otherwise healthy patients. This study was undertaken with objectives of evaluating colony forming units (CFU) on the culture media taken during ultrasonic scaling and to determine effectiveness of methods to control cross infection in dental practice due to aerosol.

Material and methods:
40 patients who had to undergo scaling were divided into two groups:
Group A:  20 patients who had undergone ultrasonic scaling without use of disinfectant
Group B:  20 patients who had undergone ultrasonic scaling after disinfection (by 0.5% sodium hypochlorite) of water tubing and water container of ultrasonic scaler attached with dental chair to control cross infection

Results:
Paired t test and Anova tests were performed for inter and intra-group analysis
The mean for group A was 3500.65 CFU and for group B was 2312.15 CFU.
Interpretation:
There was a statistically significant difference seen in the CFU seen on agar plates for group A  and group B (t=3.48, p=0.001).
Conclusion:
Within the limitations of this study we can conclude that aerosol contamination can be minimized by use of 0.5% sodium hypochlorite as a disinfecting agent.
Keywords:
Aerosol contamination, cross infection, dental procedure

Evaluation of aerosol contamination during ultrasonic scaling and root planing-with or without using dental unit tubing disinfectant
Introduction:

The oral cavity is a unique environment which provides an ideal medium for bacterial growth. Aerosol, produced during use of ultrasonic scalers and aerotors, contain infected droplets which remain in the environment for a long period of time and is a source of infection for the patient as well as the health care provider. The contaminated water in dental chair waterlines is yet another source for transmission of infection. In recent years, attention has been focused on biofilm which forms in dental chair waterlines as the potential primary source of contamination. Water stagnation, biofilm production and lack of disinfection in dental unit water systems promote the proliferation of microorganisms. 1 Reducing the microbial load in the water tubing, container and aerosol production will reduce the chances of cross infection in the dental surgery2.
There is also a concern regarding decreased air quality and potential aerosol contamination in the dental operatory. This problem has been addressed by the Center for Disease Control and Prevention, which recommends that all sources of blood-contaminated splatter and aerosol be minimized. Thus one of the major sources of potential aerosol contamination in the dental setting is the ultrasonic scaler which needs to be dealt with.

Aims and objectives:

AIM:

• The aim of the study is to evaluate aerosol bacterial contamination during ultrasonic scaling with or without implementing water system disinfection to control cross infection.

OBJECTIVES:

• To evaluate number of colonies of microorganisms on the culture media taken during ultrasonic scaling.
• To compare the growth of the microorganisms on the culture media with and without implementing water system disinfection to control cross infection.
• To determine effectiveness of methods to control cross infection in dental practice due to aerosol.

Material and Method:

STUDY DESIGN:

Patient Selection:

This study has been done on 40 patients of both sexes, who were advised to go for ultrasonic scaling. The patients were divided into two groups.
Group A:  20 patients who had undergone ultrasonic scaling
Group B:  20 patients who had undergone ultrasonic scaling with implementing methods of disinfection of water tubing and water container of ultrasonic scaler attached with dental chair to control cross infection.

Inclusion Criteria:

• Age 20-70.
• Systemically healthy

Exclusion Criteria:

• Patients having pacemaker.
• Patients having any infectious diseases.
• Primary or newly erupted teeth with large pulp chambers.
• Patients having any demineralized area.
• Patients with hypersensitivity.
• Patients with any porcelain or composite resin restorations, and titanium implants.

ARMAMENTERIUM AND MATERIALS:

• Ultrasonic unit.
• High volume suction apparatus.
• Sterile water.
• 0.5% sodium hypochlorite solution.
• Blood agar plates
• Stands for placement of agar plates.

CLINICAL PROCEDURE:
The patients taking part in the study were informed and written consent was signed. The samples were collected from the patients undergoing ultrasonic scaling at Dept. of Periodontics, K. M. Shah Dental College and Hospital, Piparia, Vadodara.
The collection of samples was done in two kind of procedures  i.e., during ultrasonic scaling without implementing methods to control cross infection (Group A) and during ultrasonic scaling implementing methods to control cross infection (Group B).
The samples included aerosol samples from ultrasonic scaler of dental chair. Blood agar plates were used to collect the aerosol sample during the experimental procedure. Blood agar plates were chosen because of its general purpose, non selective and enriched medium that promotes the growth of microorganisms such as those sampled from air. The sample plates were placed on the tray of dental chair 6 inches away from the subject’s mouth. Two plates were used on either side of the dental chair where the patient was seated. The trays were adjusted so that the base of the support board was at 50° angle to get maximum aerosol during the use of scaler of dental chair. To prevent air turbulence that can cause the dispersion of aerosol particles from the agar plate, both investigator and subject remained stationary for ten minutes after the treatment. In Group A, all these procedures were done on the dental chair with standard infection control.
In Group B, the study samples were collected during the same dental procedure after implementing methods to control aerosol contamination (irrigation with NaOCl).

The protocol used for Group A and Group B was:
a) Using a high volume suction apparatus tube kept as close as possible to the tip of ultrasonic scaler, to prevent aerosol formation.
b) Using sterile water in the water storage container of dental chair which was changed after every patient.
c) Flushing of the entire tubing of dental chair waterline with distilled water for ten minutes every day.
In addition to the above protocol, for Group B
d) 0.5% sodium hypochlorite solution was used for flushing the tubing of dental chair waterline for a period of 5 minutes. The same solution was allowed to stay in the tubing for ten minutes, followed by flushing with sterile water.
These samples were sent for microbiological culture and colony counting to the Dept. of Oral and Maxillofacial Pathology and Microbiology; K.M.Shah Dental College and Hospital; SumandeepVidyapeeth; Vadodara.  Colonies were examined and counted. A comparative analysis was carried out between Group A and Group B.

OBSERVATION AND RESULTS:

The total CFU for the test group ranged from 1268 to 4413 and for the control group it ranged from 1500 to 7118. Mean values for CFU in test and control groups are given in table 1. It was seen that the mean of Group A was 1961.7 CFU and 1538.95 CFU on the right and the left side of the patient respectively and the total of the left and right was 3500.65 CFU
The mean of Group B was 1293.4 CFU and 1018.75 CFU on the right and the left side of the patient respectively and the total of the left and right was 2312.15 CFU.
Also it was noted that the CFU were more for both the test and the control groups on the right sides when compared to their respective left sides.
Paired t test and Anova tests were performed for inter and intra-group analysis. Results are given in table 2 for intra-group analysis and table 3 for intergroup analysis. The result of this study shows statistically non-significant difference between aerosol contamination on right and left side of the patients in control group (t=2.007, p=0.51) and statistically significant difference between right and left side of patients in test group (t=2.11, p=0.04).
Statistically significant difference was found for total CFUs between test and control group (t=3.48, p=0.001).

DISCUSSION:

Research has shown that infective hazards are present in dental practice because many infections can be transmitted by blood or saliva through direct or indirect contact, droplets, aerosol or contaminated instruments or equipments. Water stagnation, biofilm production and lack of disinfection in dental unit water system promotes the proliferation of microorganisms.6
As a result of repeated exposure to the microorganisms present in blood and saliva, the dental health professionals and the patients can be placed at a higher risk for developing many infectious diseases. So the aim of this study was not to identify the individual organisms present in the samples but to assess whether any reduction was seen in the CFU after implementing the set protocol.
The result of this study shows statistically non-significant difference between aerosol contamination on right and left side of the patients in control group (t=2.007, p=0.51) and statistically significant difference between right and left side of patients in test group (t=2.11, p=0.04).

In inter-group analysis, statistically significant results are obtained when right and left sides and total of control are compared to those of test respectively (t=3.61, p=0.001; t=3.15, p=0.003; t=3.48, p=0.001 respectively).
Thus, it is observed that the cases in which ultrasonic scaling was done without implementing methods of disinfection had high CFU in comparison to the cases in which ultrasonic scaling was done with the implementation of methods of disinfection to control cross infection.
It is also observed that ultrasonic aerosol particles are more towards the right as compared to the left side.
The present study concluded that the use of 0.5% sodium hypochlorite solution was effective in reducing the microbial load. Therefore, it is an effective measure for reducing the chance of cross infection in the dental surgery. The presence of high heterotrophic bacterial counts and biofilm can be a risk for cross infection in dental surgery7 and so the use of a disinfectant should be implemented.

CONCLUSION & SUMMARY:

Within the limitations of our study, we conclude frome the results obtained that 0.5% sodium hypochlorite solution used as a disinfectant for the water tubing system of a dental chair is an effective way of preventing aerosol bacterial contamination during ultrasonic scaling.

FUTURE PERPESECTIVES:

• Isolation of specific microorganisms can be done
• Various concentrations of sodium hypochlorite can be tried to see which is the most effective
• Various other disinfecting agents can be tried to test their effectiveness.

ACKNOWLEDGEMENTS
Authors would like to acknowledge ICMR for providing stipend to the student to perform the research work. Authors would also like to acknowledge Dr. Vandana Shah, Professor, Dept. of Oral Pathology, K. M. Shah Dental College and Hospital for allowing them to use infrastructure of the department.

REFERENCES:

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Graph 1 (CFU in Control – Group A)
Graph 2 (CFU in Test – Group B)
Graph 3 (Graphical representation of compiled data)
Colony Counter:	Incubator:
Blood agar with microbial colonies formed: