Dental Water System Contamination, Control Methods and Monitoring Dr. Raghunath Puttaiah Dental-IDEAS LLC. ragu@dental-ideas.com

Introduction Dental unit water systems not cleaned/disinfected regularly, treatment water heterotrophic counts exceeds 1 million cfu/mL Salts & Mature biofilms contaminate the water system within weeks Microorganisms could be pathogenic in such high doses High doses of Endotoxins Potential for infection and disease Disinfection-by-products generated while cleaning

Biofilms, bacteria & fungi Types of Contaminants Inorganic salts (calcium, magnesium) Biofilms, bacteria & fungi Courtesy: USAF-DIS Endotoxins Trihalomethanes EPA limits: 80 ppb Identified: 8000 ppb Courtesy: PALL Corp.

Biofilm Characteristics and Formation Laser Scanning Confocal Microscopy Waterline Surface Formation of Biofilms over time Week 3 Week 8 Week 10 Week 26 >10 years

Older the system, longer to clean Clean line surface 4 – 6 weeks 8 weeks This is what we need Older the system, longer to clean >10 years 10 weeks 26 weeks

Scanning Electron Microscopy 1500 X Treatment 1 Treatment 2 Treatment 3 Controls Baseline Baseline Baseline Baseline Overnight contact Overnight contact Overnight contact Overnight contact This is what we need Post Study Post Study Post Study Post Study

Potential for Morbidity and Mortality Pseudomonas = Super-infections Mycobacterium = Lung infections Legionella = Lung and gut infection Moraxella = Bacterial Endocarditis Fungi = Fungal infections Possible high risk patients Neutropenic Patients Post Radiotherapy Uncontrolled Diabetes Spina Bifida Patients with certain Cancers Patients with other Chronic Illnesses Chronic nutritional deficiencies Lack of Surveillance - Morbidity???? Mortality ????

Evidence of disease risk Fotos et. al; JDR 1985, 64(12):1382 - 1385. 20% of students & employees in dental settings showed higher IgG antibodies to Legionella than Controls - Reinthaler et. al; JDR 1988, 67:942 - 943. High prevalence (50%) of antibodies to Legionella in dentists Oppenheim et. al; Epidemiol & Infect 1987, 99:159-166. Aerosols from dental units found to be the source of sub-clinical infection with L. pneumophila in a dental school Atlas et. al; Appl & Env. Microbiol 1995; 61(4): 1208-1213. -68% of DUW samples from 28 dental clinics had Legionella -61% of potable water from domestic/institutional faucets had at least one form of Legionella

Advances in Contamination Control

Basic Approach Towards Contamination Control Block/plug all dead-legs Clean the quick-disconnect channels and Scalers Retrofit bottle systems or use inline system Remove Existing biofilms- Need to clean/post-flush multiple times with an approved biofilm control agent/cleaner Follow Cleaner Manufacturer’s Instructions Consult with Dental Unit Manufacturer for Compatibility

Self Contained Reservoirs for Introduction of Periodic Cleaner/Disinfectant

Periodic Cleaners and Disinfectants Chlorine Dioxide Sterilex Ultra

Dental Treatment Water or Irrigant After initial cleaning dental treatment water could— -Be sterile -Be filtered/germ free -Be boiled -Be pasteurized -Be distilled -Have low mineral Content -Have low endotoxin content After initial cleaning irrigant should-- - Be a biocompatible low grade germicide - Be compatible with equipment - Be compatible with composite bonding to enamel and dentin - Not form disinfection-by-products

Irrigant Generating Devices Sterisil Dentapure

Devices to Improve Water Quality BluTab ICX

Corrosion

Corrosion 20 days 60 days

Corrosion-Elemental Metal Analysis

Irrigant Compatibility with Bonding Adhesive failure Cohesive failure Double Blinded Studies better Survival Analysis Censored Data Analysis Mixed failure

Monitoring of Microbial Quality Screening Vs. Diagnostic tests 1. HPC Water Samplers (Millipore Inc.) 2. Aquasafe Samplers (Pall Corp.) 3. R2A Agar is the Gold Standard The error rate of HPC samplers was >40% When compared to R2A (Puttaiah, et al, AADR 2001; Abstract JDR) Significant decrease in detection by HPC and Aquasafe in comparison to R2A (Puttaiah, et al, AADR 2002; Abstract JDR) 1 2 3