Interventions to reduce contaminated aerosols produced during dental procedures for preventing infectious diseases.

BACKGROUND: Many dental procedures produce aerosols (droplets, droplet nuclei and splatter) that harbour various pathogenic micro-organisms and may pose a risk for the spread of infections between dentist and patient. The COVID-19 pandemic has led to greater concern about this risk. OBJECTIVES: To assess the effectiveness of methods used during dental treatment procedures to minimize aerosol production and reduce or neutralize contamination in aerosols. SEARCH METHODS: Cochrane Oral Health's Information Specialist searched the following databases on 17 September 2020: Cochrane Oral Health's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (in the Cochrane Library, 2020, Issue 8), MEDLINE Ovid (from 1946); Embase Ovid (from 1980); the WHO COVID-19 Global literature on coronavirus disease; the US National Institutes of Health Trials Registry (ClinicalTrials.gov); and the Cochrane COVID-19 Study Register. We placed no restrictions on the language or date of publication. SELECTION CRITERIA: We included randomized controlled trials (RCTs) and controlled clinical trials (CCTs) on aerosol-generating procedures (AGPs) performed by dental healthcare providers that evaluated methods to reduce contaminated aerosols in dental clinics (excluding preprocedural mouthrinses). The primary outcomes were incidence of infection in dental staff or patients, and reduction in volume and level of contaminated aerosols in the operative environment. The secondary outcomes were cost, accessibility and feasibility. DATA COLLECTION AND ANALYSIS: Two review authors screened search results, extracted data from the included studies, assessed the risk of bias in the studies, and judged the certainty of the available evidence. We used mean differences (MDs) and 95% confidence intervals (CIs) as the effect estimate for continuous outcomes, and random-effects meta-analysis to combine data. We assessed heterogeneity. MAIN RESULTS: We included 16 studies with 425 participants aged 5 to 69 years. Eight studies had high risk of bias; eight had unclear risk of bias. No studies measured infection. All studies measured bacterial contamination using the surrogate outcome of colony-forming units (CFU). Two studies measured contamination per volume of air sampled at different distances from the patient's mouth, and 14 studies sampled particles on agar plates at specific distances from the patient's mouth. The results presented below should be interpreted with caution as the evidence is very low certainty due to heterogeneity, risk of bias, small sample sizes and wide confidence intervals. Moreover, we do not know the 'minimal clinically important difference' in CFU. High-volume evacuator Use of a high-volume evacuator (HVE) may reduce bacterial contamination in aerosols less than one foot (~ 30 cm) from a patient's mouth (MD -47.41, 95% CI -92.76 to -2.06; 3 RCTs, 122 participants (two studies had split-mouth design); very high heterogeneity I² = 95%), but not at longer distances (MD -1.00, -2.56 to 0.56; 1 RCT, 80 participants). One split-mouth RCT (six participants) found that HVE may not be more effective than conventional dental suction (saliva ejector or low-volume evacuator) at 40 cm (MD CFU -2.30, 95% CI -5.32 to 0.72) or 150 cm (MD -2.20, 95% CI -14.01 to 9.61). Dental isolation combination system One RCT (50 participants) found that there may be no difference in CFU between a combination system (Isolite) and a saliva ejector (low-volume evacuator) during AGPs (MD -0.31, 95% CI -0.82 to 0.20) or after AGPs (MD -0.35, -0.99 to 0.29). However, an 'n of 1' design study showed that the combination system may reduce CFU compared with rubber dam plus HVE (MD -125.20, 95% CI -174.02 to -76.38) or HVE (MD -109.30, 95% CI -153.01 to -65.59). Rubber dam One split-mouth RCT (10 participants) receiving dental treatment, found that there may be a reduction in CFU with rubber dam at one-metre (MD -16.20, 95% CI -19.36 to -13.04) and two-metre distance (MD -11.70, 95% CI -15.82 to -7.58). One RCT of 47 dental students found use of rubber dam may make no difference in CFU at the forehead (MD 0.98, 95% CI -0.73 to 2.70) and occipital region of the operator (MD 0.77, 95% CI -0.46 to 2.00). One split-mouth RCT (21 participants) found that rubber dam plus HVE may reduce CFU more than cotton roll plus HVE on the patient's chest (MD -251.00, 95% CI -267.95 to -234.05) and dental unit light (MD -12.70, 95% CI -12.85 to -12.55). Air cleaning systems One split-mouth CCT (two participants) used a local stand-alone air cleaning system (ACS), which may reduce aerosol contamination during cavity preparation (MD -66.70 CFU, 95% CI -120.15 to -13.25 per cubic metre) or ultrasonic scaling (MD -32.40, 95% CI - 51.55 to -13.25). Another CCT (50 participants) found that laminar flow in the dental clinic combined with a HEPA filter may reduce contamination approximately 76 cm from the floor (MD -483.56 CFU, 95% CI -550.02 to -417.10 per cubic feet per minute per patient) and 20 cm to 30 cm from the patient's mouth (MD -319.14 CFU, 95% CI - 385.60 to -252.68). Disinfectants ‒ antimicrobial coolants Two RCTs evaluated use of antimicrobial coolants during ultrasonic scaling. Compared with distilled water, coolant containing chlorhexidine (CHX), cinnamon extract coolant or povidone iodine may reduce CFU: CHX (MD -124.00, 95% CI -135.78 to -112.22; 20 participants), povidone iodine (MD -656.45, 95% CI -672.74 to -640.16; 40 participants), cinnamon (MD -644.55, 95% CI -668.70 to -620.40; 40 participants). CHX coolant may reduce CFU more than povidone iodine (MD -59.30, 95% CI -64.16 to -54.44; 20 participants), but not more than cinnamon extract (MD -11.90, 95% CI -35.88 to 12.08; 40 participants). AUTHORS' CONCLUSIONS: We found no studies that evaluated disease transmission via aerosols in a dental setting; and no evidence about viral contamination in aerosols. All of the included studies measured bacterial contamination using colony-forming units. There appeared to be some benefit from the interventions evaluated but the available evidence is very low certainty so we are unable to draw reliable conclusions. We did not find any studies on methods such as ventilation, ionization, ozonisation, UV light and fogging. Studies are needed that measure contamination in aerosols, size distribution of aerosols and infection transmission risk for respiratory diseases such as COVID-19 in dental patients and staff.

The assessment of infection control in dental practices in the municipality of São Paulo.

OBJECTIVE: The goal of this study was to evaluate the infection control measures actually implemented by dental surgeons during dental practice, as patients and professionals are exposed to high biological risk in dental care environments. METHOD: 614 questionnaires (90.69%) were answered by professionals registered in updating or in post-graduate courses in the Municipality of São Paulo. RESULTS: Out of surveyed professionals 30.62% admitted that surface protection barriers were not used, whereas 34.17% were using non ideal or outdated pre-disinfection practices. The autoclave was used by 69.38% of participants, although 33.80% were not monitoring control of the sterilization cycles. Chemical and biological indicators were not used simultaneously by 83.21% of respondents and were not employed on a daily or weekly basis by at least 81.75%. Dubious methods of sterilization were cited by 44.77%. Occupational accidents caused by cutting and piercing objects were reported by 47.88%; however, the biologic risk was underestimated by 74.15% of the professionals who suffered the accidents. Irritant solutions were used as an antiseptic agent by 18.55%. CONCLUSIONS: Infection control measures reported by dental surgeons during their practices are deficient. It is necessary to educate, raise awareness of professionals, and promote constant updating courses on procedures which aim at improving safety of dental care.

A quantitative assessment of residual protein levels on dental instruments reprocessed by manual, ultrasonic and automated cleaning methods.

OBJECTIVE: To assess residual protein on dental instruments cleaned in general dental practice by manual, manual plus ultrasonic and automated washer disinfector (AWD) processes. DESIGN AND SETTING: Instruments submitted by 30 dental surgeries in the South West of England. SUBJECTS (MATERIALS) AND METHODS: Instruments analysed were matrix bands, associated retaining clips, diamond and stainless steel burs, extraction forceps and hand scalers. Each instrument was visually assessed under magnification for residual debris. Residual protein was extracted by immersion in detergent and sonication. A collection of used but uncleaned instruments of each type (n = 177) was also analysed for adherent protein using ophthalaldehyde/N-acetylcysteine reagent. MAIN OUTCOME MEASURES: Residual protein levels allowed comparisons to be made on the effectiveness of different cleaning processes. RESULTS: One thousand, three hundred and four instruments were analysed. Observational data demonstrated several shortcomings in cleaning chemistries and operation of the AWD. For uncleaned instruments, median residual protein levels ranged from 0.4 µg (stainless steel burs) to 462 µg (extraction forceps). Following manual washing, median protein levels ranged from 0.3-78 µg; for manual plus ultrasonic washing, levels ranged from 9-39 µg and AWD levels ranged from 0.3-27 µg. Manual washing combined with ultrasonic cleaning was significantly less effective than the other two processes (p <0.008). AWDs reduced the variability in the cleaning process. No correlation was found between visual scoring and residual protein determination. CONCLUSION(S): There was a wide variation in residual protein levels both within and between different methods and instruments and this underlines the complexity of this process.

The assessment of infection control in dental practices in the municipality of São Paulo

OBJECTIVE: The goal of this study was to evaluate the infection control measures actually implemented by dental surgeons during dental practice, as patients and professionals are exposed to high biological risk in dental care environments. METHOD: 614 questionnaires (90.69 percent) were answered by professionals registered in updating or in post-graduate courses in the Municipality of São Paulo. RESULTS: Out of surveyed professionals 30.62 percent admitted that surface protection barriers were not used, whereas 34.17 percent were using non ideal or outdated pre-disinfection practices. The autoclave was used by 69.38 percent of participants, although 33.80 percent were not monitoring control of the sterilization cycles. Chemical and biological indicators were not used simultaneously by 83.21 percent of respondents and were not employed on a daily or weekly basis by at least 81.75 percent. Dubious methods of sterilization were cited by 44.77 percent. Occupational accidents caused by cutting and piercing objects were reported by 47.88 percent; however, the biologic risk was underestimated by 74.15 percent of the professionals who suffered the accidents. Irritant solutions were used as an antiseptic agent by 18.55 percent. CONCLUSIONS: Infection control measures reported by dental surgeons during their practices are deficient. It is necessary to educate, raise awareness of professionals, and promote constant updating courses on procedures which aim at improving safety of dental care.

Survey of instrument decontamination in dental surgeries located in Scottish prisons.

We describe an observational study in which the policies and procedures of dental surgeries in 14 of the 15 Scottish prisons for sterilizing instruments were viewed directly by a trained surveyor. The survey found that several key elements in the decontamination cycle, ranging from procurement of devices, cleaning, sterilizing, testing, maintenance, quality management and training were deficient in a number of aspects. The use of a central sterile supply service may be a more cost effective approach for the provision of compliant instrument reprocessing facilities in the sites surveyed.

Improving the provision of the Basic Package of Oral Care (BPOC) in Cambodia.

UNLABELLED: Since 1992, 330 medical nurses have been trained to provide basic oral health care (including ART restorations and dental extractions) in remote areas of Cambodia. However, a range of barriers prevent dental nurses from providing these services, especially a lack of dental materials and instruments. OBJECTIVES: To increase dental nurse (DN) outputs through the regular provision of dental materials and instruments. To improve cross-infection control procedures through the provision of necessary equipment, supplies and training. METHODS: Six health centres with active DNs participated; three (experimental) health centres received sufficient supplies of dental instruments and materials for one year, and 3-monthly visits by a dentist from the Ministry of Health. The other three health centres (control) did not. RESULTS: During the project period, the experimental group extractions increased to an average of 119 extractions per quarter (a three-fold increase compared to the baseline), 51 ART restorations, and improved compliance with cross-infection infection control protocols. In the control group the number of extractions remained similar to baseline and no ART restorations were placed. CONCLUSIONS: The provision of the BPOC increased in the health centres when sufficient supplies of dental materials and instruments were provided. Increased monitoring and communication with MOH dental colleagues was also associated with the increased outputs and resulted in improved compliance with cross-infection control protocols. The MOH should increase supplies to DNs and provide ongoing monitoring and support in order to improve the access to and quality of dental care provided in rural Cambodia.

Infection control: a survey of UK special care dentists and dental care professionals.

AIM: To determine attitudes to and practice of infection control among practitioners involved in special care dentistry. METHODS: A questionnaire on the issues of decontamination and infection control was sent to all 680 members of the British Society for Disability and Oral Health. RESULTS: The response rate was 63.5%. Almost all respondents (95%) reported having a local infection-control policy; most (97%) had local protocols for the management of inoculation injuries; most (81%) gave new staff training in infection-control procedures and most (74%) provided updates for established staff. Most respondents 'usually' or 'always' provided eye protection for patients (95%) and themselves (93%). Virtually all routinely wore gloves, and nearly all (94%) 'always' changed gloves between patients. The majority 'usually' or 'always' disinfected or disposed of surface coverings between patients (98%), sterilised all non-disposable instruments that had been set out for the patient (99%), and disinfected laboratory work (96%). CONCLUSIONS: There was high awareness of infection-control issues, and good reported compliance among these dental workers.

Assessment of the risk of glove puncture during oral surgery procedures.

PURPOSE: The purpose of this study was to examine the incidence of glove puncture during stages of oral surgery procedures. METHOD: One surgeon was requested to wear one type of sterile operating gloves during the treatment of patients who required an oral surgery procedure under outpatient local anesthesia. Each surgical procedure was divided into three modules, namely, (I) administration of the anesthesia and raising of mucoperiosteal flap, (II) bone removal and delivery of the tooth or root, and, (3) soft tissue repair. A total of 450 gloves worn during these modules were examined for punctures with a water inflation method and 200 unused gloves were tested as controls. RESULTS: The results were analyzed statistically with Fischer's exact test. A total of 12 punctures were recorded, indicating that a glove puncture occurred in 16% of the surgical procedures. Gloves from the left hand (the nonworking hand) in module III showed the highest incidence of punctures. One puncture was observed in the 200 gloves tested as controls. Statistical analysis indicated that glove puncture was significantly more likely to occur in gloves worn on the left (nonworking) hand overall as compared with gloves from the right hand (p = 0.02) and that glove puncture was significantly more likely to occur in gloves worn on the left hand in module III as compared with gloves from other modules (p = 0.01). Additional precautions may therefore be indicated during the soft tissue repair part of oral surgical procedures.