High-volume Evacuation Research Articles

A Study to evaluate and compare the Efficacy of Preprocedural Mouthrinsing and High Volume Evacuator Attachment Alone and in Combination in Reducing the Amount of Viable Aerosols Produced during Ultrasonic Scaling Procedure

In recent years, ultrasonics has gained prime importance and is considered a valuable tool in the dentist's armamentarium. Studies have confirmed that an aerosolized bacterial contamination is produced during the use of ultrasonic scalers. To evaluate and compare the efficacy of preprocedural mouthrinsing using a bis-biguanide (chlorhexidine gluconate 0.2%) and high volume evacuator attachment alone and in combination in reducing the amount of viable aerosols produced during ultrasonic scaling procedure. A total 90 subjects were assigned to group I (who rinsed with 0.2% chlorhexidine gluconate prior to scaling), group II (high volume evacuator attachment was used during ultrasonic scaling) and group III (who rinsed with 0.2% chlorhexidine gluconate prior to scaling and in whom high volume evacuator attachment was used during ultrasonic scaling). Control group consisted of subject's whose mouth was scaled using a piezoelectric ultrasonic scaler without preprocedural rinsing or high volume suction. Aerosol samples were collected using blood agar plates. The blood agar plates containing the aerosol sample were taken to the microbiology department as soon as the sampling was over and were subjected to aerobic culturing. The values obtained showed that all the three groups were effective in reducing the mean colony forming units (CFUs). The results of this study showed that preprocedural rinse and high volume suction were effective when used alone as well as together in reducing the microbial load of the aerosols produced during ultrasonic scaling. There was a significant reduction in the number of CFUs in aerosol samples obtained.

Determination of Minimum Suction Level Necessary for Field Dental Units

A significant problem with most field dental units is that their suction is too weak to effectively remove debris from the mouth. The purpose of this study was to determine the minimum clinically acceptable suction level for routine dentistry. A vacuum pump was connected to a high-volume dental evacuation line in a simulated clinical setting and different suction airflow rates were evaluated by nine evaluator dentists for their capability to effectively remove amalgam debris and water. Airflow levels were rated as "clinically acceptable" or "clinically unacceptable" by each evaluator. Data were analyzed using a chi2 test for trend. Analysis indicated a significant linear trend between airflow and ratings (p < 0.0001). The first airflow level considered by all evaluators as producing clinically acceptable suction was 4.5 standard cubic feet per minute (0.127 standard cubic meters per minute). This value should be the minimum level required for all military field dental units.

Quantitative and qualitative analysis of particulate production during simulated clinical orthodontic debonds

Objectives The objectives of this investigation were firstly to quantitatively and qualitatively determine particulate production during orthodontic debond and enamel cleanup procedures, and secondly to examine what methods can be employed to minimize operator exposure to such dust particles. Methods A qualitative study was performed to determine the aerodynamic diameters and compositions of particulates produced during simulated clinical debonds and enamel cleanup procedures on extracted teeth. In each case the enamel was cleaned using tungsten carbide burs in either a high or slow speed handpiece, with or without water coolant spray, with or without high volume evacuation (HVE) or a face mask. Results The use of a high speed handpiece with a tungsten carbide bur and water irrigation at enamel cleanup produced the greatest concentration of respirable particulates. Within this dust, calcium, phosphorus, aluminum and silicon were the most commonly found elements. The dust levels observed did not exceed limits advised for respirable dusts in general. However, the concentration of silica within the dusts created is unknown. The face mask and HVE were effective at reducing exposure to respirable particles, but the mask was most effective, reducing exposure by up to 96%. Significance A face mask is an effective means of reducing dust inhalation and is advised for all clinical procedures that produce dusts.

Aerosols and Splatter in Dentistry – A Neglected Menace?

Two main types of particulate matter may be produced during routine dental procedures, namely aerosols and splatter. The principal difference between them is the size of the particles from which they are made. The behaviour of such particles in air and their possible health risks are complex. However, the use of high volume evacuation, pre-procedural mouthrinses and rubber dam are the most effective methods of reducing the unwanted risk of exposure.

Aerosols and splatter in dentistry: A brief review of the literature and infection control implications

BackgroundAerosols and droplets are produced during many dental procedures. With the advent of the droplet-spread disease severe acute respiratory syndrome, or SARS, a review of the infection control procedures for aerosols is warranted.Types of Studies ReviewedThe authors reviewed representative medical and dental literature for studies and reports that documented the spread of disease through an airborne route. They also reviewed the dental literature for representative studies of contamination from various dental procedures and methods of reducing airborne contamination from those procedures.ResultsThe airborne spread of measles, tuberculosis and SARS is well-documented in the medical literature. The dental literature shows that many dental procedures produce aerosols and droplets that are contaminated with bacteria and blood. These aerosols represent a potential route for disease transmission. The literature also documents that airborne contamination can be minimized easily and inexpensively by layering several infection control steps into the routine precautions used during all dental procedures.Clinical ImplicationsIn addition to the routine use of standard barriers such as masks and gloves, the universal use of pre-procedural rinses and high-volume evacuation is recommended.

A study on dental vacuum system losses.

An experimental study was conducted to document system head losses for dental vacuum systems. Experiments were performed to estimate pressure losses and pressure loss coefficients for pertinent dental treatment room hoses and fittings in high-volume evacuation systems. Pressure losses for some polyvinyl chloride (PVC) elbows used in dental plumbing systems were also measured and presented. Friction head losses in straight PVC piping are calculated and documented in graphical form. Calculated values for friction losses are found to correlate exceptionally well with measured experimental data.

AEROSOL AND SPLATTER CONTAMINATION FROM THE OPERATIVE SITE DURING ULTRASONIC SCALING

As concern about indoor air quality increases, attention is being placed on the aerosol and splatter produced during dental procedures. This study quantifies the contamination produced by ultrasonic scalers during in vitro scaling without coolant water. When compared with the handheld curette used as a control, all ultrasonic scalers and tips tested produced significant aerosol and splatter regardless of the type of scaler, the power level or the insert. The ADA-recommended method for controlling contaminated aerosol and splatter is the use of a large-bore high-volume evacuator. This study supports the ADA recommendation of use of a high-volume evacuator whenever ultrasonic scaling is performed.

Blood contamination of the aerosols produced by in vivo use of ultrasonic scalers.

Disease transmission and barrier techniques during dental treatment have been areas of recent concern in dentistry. Ultrasonic scalers are known to produce aerosols, and these aerosols are often produced from areas of significant disease activity, including bleeding. This study was performed to determine if these aerosols contain blood from the gingival sulcus. Forty areas consisting of two contiguous periodontally involved teeth (probing depth of at least 5 mm on one site of each tooth) were scaled subgingivally with an ultrasonic scaler for 30 seconds. A high volume evacuator (HVE) tip was positioned 3 to 5 cm away from the operating site and utilized to capture the aerosols produced. The water remaining in and on the HVE tube was tested for occult blood by the guiac resin method. Gingival index, mean probing depth, presence of bleeding with scaling, and presence of visible blood in the HVE tip were recorded. All 40 test sites showed a positive result for blood in the captured aerosols despite the wide variation in the measured parameters. It may be concluded that subgingival scaling on periodontally involved teeth with ultrasonic scalers would be expected to produce aerosols containing blood.

Mercury levels in plasma and urine after removal of all amalgam restorations: The effect of using rubber dams

Objective The aim of the present study was to determine whether removal of all amalgam restorations might significantly affect mercury levels in plasma and urine and whether the use of rubber dams might reduce patient exposure to mercury during amalgam removal. Methods All amalgam restorations were removed from 18 subjects during a single treatment session in which a rubber dam was used and from 10 subjects when a rubber dam was not used. All amalgam restorations were removed by the same dentist using high-speed cutting, water coolant, and high-volume evacuation. The levels of mercury in plasma and urine were analyzed both before and during the subsequent twelve months after amalgam removal. In order to determine whether removal of all amalgam restorations might cause an exposure large enough to significantly increase the mercury levels in two indicator media for mercury exposure, i.e., plasma and urine, and to determine if the removal might cause a significant decrease in the mercury levels found over time, the one-tailed, paired Students' t-test was used. For each individual, the pre-removal levels were compared with both the levels found in plasma on d 1 and in urine on d 10, and also with the levels found 1 y after removal. Furthermore, in order to examine whether the use of rubber dams had any effect on the mercury levels found after removal, the changes in the mercury levels found were compared between the groups using the Wilcoxon-Mann-Whitney rank sum test. Results After removal of all amalgam restorations, only the non-rubber dam group showed significant increases in the mercury levels found in plasma (p=0.012) and urine (p=0.037). However, one year later, the mercury levels in plasma and urine had sunk significantly below the pre-removal levels for both groups. When the changes in the mercury levels found were compared between the groups, the non-rubber dam group showed a significantly higher increase of mercury in plasma than the rubber dam group the day after removal (p=0.0010). Compared to the pre-removal mercury levels in plasma and urine, the levels found 1 y after removal of all amalgam restorations were on average 52 t 23% (range 4 – 89%) lower in plasma and 76 f 21 % (range 20 – 94%) lower in urine. Significance The study showed that dental amalgam had a statistically significant impact on the mercury levels found in plasma and urine in the patients tested, and that the use of a rubber dam during removal of all amalgam restorations significantly reduced the peak of mercury in plasma following removal.

The dentist's exposure to elemental mercury vapor during clinical work with amalgam.

Continuous measurements of mercury vapor in the breathing zone of the dentist were made under ordinary clinical conditions. Fifty old amalgam fillings were removed and replaced by new ones. The mercury vapor measurements were performed by means of atomic absorption spectrophotometry. On the basis of the type of suction device used, the measurements were divided into seven groups, each of which consisted of a series of measurements. During the cutting, filling, and polishing operations the mean mercury vapor levels in the breathing zone of the dentist were in the range of 1-2 micrograms Hg m-3 air when proper mercury hygiene measures were taken. This is far below the currently valid threshold limit value (30 micrograms Hg m-3 air) in Sweden. The saliva extractor and the dental mirror-evacuator did not influence the mercury vapor levels when used together with the high-volume evacuator. However, when only a saliva extractor was used, the cutting of amalgam fillings caused highly fluctuating mercury vapor levels, which were 2-15 times higher than the threshold limit value.

Quantitation of total mercury vapor released during dental procedures

An in vitro method is described in which measurements were made of the total amount of mercury vapor released from three types of amalgam during routine dental procedures. It was found that the greatest amount of mercury was released during dry polishing of one amalgam (44 μg). Removal of amalgam from a Class I cavity under water spray and high volume evacuation also generated large amounts of mercury as expected (15–20 μg). However, under the more clinically relevant conditions of extending evacuation for one minute to remove residual amalgam and mercury after cutting, this value was reduced by approximately 90%. The total amount of mercury generated during placement (6–8 μg), wet polishing (2–4 μg) and trituration (1–2 μg) were also measured. The study showed that dental procedures associated with amalgam do potentially expose the patient and operator to mercury vapor. However, the total amount of mercury released during any procedure was far below the total exposure level calculated from the daily threshold limits established by regulatory agencies for occupational exposure.

Effects of methantheline bromide and clonidine hydrochloride on salivary secretion

T he maintenance of an operative field free of moisture contamination is important in many dental procedures. Impression materials such as the silicones and polysulfides possess hydrophobic properties. Cements, amalgam, and composite resins exhibit weakened or altered physical properties when contaminated with moisture. Finally, equilibration procedures that require the use of inked ribbon are virtually impossible to perform without adequate saliva control. Many devices have been used to control saliva during dental treatment: cotton rolls, absorbent papers and other moisture absorbing materials, saliva ejectors, and high volume evacuators. Various drugs have also been successfully used but are often prohibited by potential side effects. Methantheline bromide was originally intended for use in the treatment of peptic ulcers.‘,’ It has long been considered an effective antisialagogue;3,4 however, potential side effects in both the healthy and compromised patient have prevented its widespread and routine use.2,3 An antihypertensive, clonidine hydrochloride, has shown merit recently in reducing saliva output with minimal side effects and fewer contraindications than methantheline bromide.5-9 The purposes of this study were 1) to compare in a double-blind fashion the inhibition of stimulated salivary output produced with clonidine hydrochloride, methantheline bromide, and a placebo in healthy volunteers and 2) to discern the effects of a standard meal on the action of clonidine hydrochloride.

High Volume Evacuation

High Volume Evacuation