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Clinical techniques of performing suctioning tasks and of positioning the High Volume Evacuation (HVE) attachment and inlet when assisting a dentist: a guide for dental assistants: part 2.

When assisting a dentist, an assistant may need to hold the high volume evacuation (HVE) attachment and use it to suction aerosols produced by the dentist's tools, particularly the high speed handpiece or the cavitron. The main objective of suctioning is to hold the inlet of the HVE attachment close enough to the source of aerosols to evacuate those aerosols, while avoiding suctioning of the patient's intra-oral soft tissues, and avoiding contact of the HVE attachment with the handpiece, cavitron or other instrument that the dentist is using. In general, assisting a dentist with suctioning is a somewhat complex skill that may require months of experience before an assistant develops an intuition for suctioning. This is the second part of a two-part article, and focuses on how to position the HVE suction inlet at various locations intra-orally and on how to maintain and clean the dental office suction pipes.

The following explains general ways of positioning the HVE shaft and inlet, given which specific teeth and surfaces the dentist is working on. (1) Generally, the assistant should position the shaft of the HVE attachment on the opposite side of where the dentist's hand mirror and aerosol-producing instrument are located, to reduce the chance of the HVE shaft or inlet obstructing the dentist's view of the work area. In addition, the assistant should position the plane of the HVE inlet so that it is oriented slightly occlusal and lateral to the source of the aerosols. The assistant should visualize and be continually aware of the imaginary axis between the dentist's eyes and the viewing surface of the mouth mirror, so as to avoid placing the HVE attachment within this axis.

However, there maybe exceptions to these generalities and sometimes common sense provides the best guide for optimally positioning the HVE inlet. If intra-oral placement of the HVE attachment is not practical, the assistant may need to position the HVE inlet slightly outside the mouth opening. This may occur when a patient's mouth is very small, such as with pediatric patients, or with patients who may pucker their lips to restrict the size of the their mouth opening due to anxiety, making it difficult to place an HVE inlet intra-orally.

Buccal surfaces of right maxillary posterior teeth, for a right-handed dentist

When the dentist is working on the buccal surfaces of the right maxillary posteriors, the dentist is generally using direct vision. The assistant generally positions the HVE suction inlet lingual to the teeth being worked on, with the HVE shaft protruding laterally towards the side of the patient's face that is opposite the side where the teeth that the dentist is working on are located. Ideally, the assistant would position the HVE inlet on the buccal aspect of the teeth that the dentist is working on, with the inlet approximately at a right angle to the occlusal surface of the teeth, or with the inlet slightly occlusal to the occhsal surface and facing the occlusal surface. However, it can be difficult to position the HVE shaft on the buccal side so that it is not interfering with the dentist's placement of the instruments, especially if there is limited space between the ramus aspect of the mandible and the buccal aspect of the maxillary posterior area, or if tight cheek muscles prevent thick objects like the HVE shaft from accessing the maxillary buccal vestibule.

If the right-handed dentist is working on the buccal surfaces of the maxillary left posteriors, the dentist may position his or her body on the left side of the patient's mouth in order to obtain a direct vision view of those surfaces. The assistant may then have to position him or herself on the right side of the patient's face in order to be out of the dentist's way, and position the HVE inlet lingual to the teeth being worked on, with the HVE shaft protruding laterally towards the patient's right side.

Occlusal and lingual surfaces of right maxillary posterior teeth, for a right-handed dentist

Sometimes, the right-handed dentist works on the occlusal or lingual surfaces of the maxillary posterior teeth using indirect vision. The dentist's handpiece will occupy the space along the occlusal and buccal aspects of the right posterior teeth, while the mouth mirror will occupy the lingual aspects of the posterior teeth from the maxillary molar being worked on to the maxillary anterior dentition. The assistant generally places the HVE inlet just posterior to or just lingual to the mouth mirror, and tries not to obstruct the dentist's line of sight to the viewing surface of the mirror. The HVE shaft protrudes towards the side of the patient's mouth opposite the side that the dentist is working on, or perhaps straight anteriorly.

If the patient's mouth is small, the assistant may have minimal room for positioning the HVE inlet and shaft, and risks poking the patient's throat or jabbing the patient's tongue posteriorly. Here, the dentist may have the assistant position the HVE inlet just outside of the opening of the patient's mouth.

When the right-handed dentist is workbag on the lingual surfaces of the right maxillary posterior teeth using direct vision, the assistant generally positions the HVE inlet facing the occlusal surface of the teeth being worked on, or perhaps facing the lingual side just inferior to the teeth being worked on, with the HVE shaft protruding out towards the anterior of the patient's mouth.

Left mandibular posterior teeth, for a right-handed dentist

Generally, the right-handed dentist's aerosol-producing instrument will be positioned lingual to the teeth when working on the left mandibular posteriors, and the dentist will use the mouth mirror to retract the tongue. The assistant holds the HVE attachment so that the shaft of the HVE is roughly parallel to the left buccal mucosa, and the plane of the opening of the HVE inlet is parallel with the buccal surface of the tooth being worked on, or the opening can be held slightly occlusal to where the dentist is working.

The dental assistant can use his or her own mirror to retract the buccal mucosa, or place a dry angle there, if the mucosa interferes with the shaft of or inlet of the HVE attachment or gets sucked into it. Sometimes, the dentist may move to the patient's left to get a direct vision view of the buccal surfaces of the mandibular posteriors. In this case, the assistant may need to move to the patient's right to position the HVE inlet lingually and to retract the patient's tongue with a mouth mirror.

[FIGURE 1 OMITTED]

Right mandibular posterior teeth, for a right-handed dentist

When working on occlusal or buccal surfaces of the right mandibular posteriors, the shaft of the dentist's aerosol-producing instrument will generally be oriented towards the patient's right lateral side. The dentist typically retracts the buccal mucosa with the mouth mirror, but the assistant may also need to retract the tongue with the flat end of an instrument or a mouth mirror. The HVE shaft is positioned lingual to the right mandibular teeth being worked on, with the shaft protruding towards the left anterior teeth or left mouth opening. The HVE inlet can be positioned lingual to or slightly occlusal to the teeth being worked on.

When working on the lingual surfaces of the right mandibular teeth, the dentist may move to the patient's left, so that the shafts of the dentist's instruments protrude towards the patient's left, and the dentist would retract the tongue. The assistant would move to the patient's right side and position the HVE shaft buccal to the teeth being worked on, with the inlet facing the occlusal surfaces of the teeth. The assistant also retracts the buccal mucosa with a mouth mirror.

Mandibular anterior teeth, for a right-handed dentist

When the dentist is working on the lingual surfaces of the mandibular anteriors, the assistant generally positions the HVE suction tip facial and occlusal to the mandibular anterior teeth, and uses a flat surface to retract the lower anterior lip, while the HVE shaft protrudes extra-orally towards the patient's left lateral side. The assistant may also sometimes position the HVE inlet on the lingual side of the anterior teeth, with the plane of the inlet positioned occlusal to or facing the dentist's aerosol--producing instrument (Figure 1, above). Cotton rolls, or a dry angle that is cut in half and fitted into the anterior facial vestibule, aid in retraction if the lip is too slippery to retract easily.

When the right-handed dentist at the patient's 10 o'clock position is working on the facial surfaces of mandibular anteriors, the assistant can position the HVE inlet on the facial side of the anterior teeth, with the inlet facing the aerosol-producing instrument or just occlusal to the instrument. The HVE shaft may protrude towards the left side of the patient's mouth opening.

Sometimes when working on the mandibular facial surfaces, the dentist physically positions his or her body at the patient's four through eight o'clock position. Here, the shafts of the dentist's instruments protrude towards the anterior on the side where the dentist is working. Generally, the assistant positions the HVE inlet at the lingual, with the plane of the inlet facing the aerosol-producing instrument, and the shaft of the HVE inlet protruding towards the superior posterior aspect of the patient's mouth. The assistant may have to physically move his or her body to allow for appropriate positioning of the HVE inlet and shaft.

Maxillary anterior teeth, for a right-handed dentist

When the right-handed dentist is working on the facial surfaces of the maxillary anterior teeth, the assistant positions the HVE inlet on the facial side, with the inlet facing the aerosol--producing instrument, and HVE shaft protruding laterally towards the patient's left.

When the dentist is working on the lingual surfaces of the maxillary anterior teeth, the dentist uses a mouth mirror, so the assistant must be careful not to position the HVE inlet in the dentist's line of sight to the mouth mirror surface. The handpiece aerosol will move in a facial direction, but it may be difficult to place the HVE inlet facially in the direction of the aerosols since this will likely be in the dentist's line of sight. Instead the assistant may position the HVE inlet at the lingual, just left of the mouth mirror. The assistant may also try placing the HVE inlet facially with the inlet facing the handpiece to see if such positioning evacuates the aerosols.

Suctioning of debris that collects in the patient's mouth

A combined air/water spray is useful for dislodging tiny particles of dust that are embedded in tiny crevices in the patient's tongue or are caked on the patient's buccal mucosa. The HVE inlet then suctions the spray with the particles in it.

[FIGURE 2 OMITTED]

In addition, a stream of pure water from the air/water syringe, directed in a posterior inferior direction so that it flows along the maxillary palate, creates a pool of water at the back of the throat that floats up debris within the patient's mouth. The assistant suctions the water containing the debris by positioning the HVE inlet near the retromolar pad on the side opposite to where the air/ water syringe tip is located. Water then flows across the base of the tongue like a stream, carrying debris towards the inlet (Figure 2, above). A stream of pure water should be aimed carefully, since if it hits an intra-oral surface with too much force it may "bounce back" and wet the dentist or assistant.

To suction debris under the posterior aspect of the tongue in the lingual vestibule, the dentist can use a mouth mirror to lift up the tongue at the posterior aspect so as to squirt water under the tongue to float up debris for suctioning using the HVE suction tip. Debris under the posterior aspect of the tongue should be suctioned before the patient leaves the operatory, since it may be difficult for a patient to rinse out such debris, especially if the tongue is anesthetized.

Sometimes the mucosa forms a subtle crease at the retromolar pad area. This crease may be difficult to see and retract, and may hide debris or amalgam crumbs. The assistant should retract any such crease after the procedure is completed to see if it hides debris that should be suctioned. To provide access for suctioning the retromolar pad area of the patient's mouth, the HVE shaft should be held so that its shaft and inlet are essentially parallel to the plane of the patient's buccal mucosa, with the dorsal aspect of the HVE inlet retracting the tongue. Positioning the shaft so that it protrudes superiorly and anteriorly, versus just anteriorly in front of the patient's mouth, can also facilitate access of the HVE suction tip to the corner of the patient's mouth.

Concentrating the suction power of the chairside HVE suction

As a rule of thumb, the HVE suction is strong enough if, when the assistant touches the HVE inlet to the palm of the gloved hand, the suction instantly sucks the glove tightly, and then when the assistant pulls the suction inlet away from the palm, a somewhat loud "snapping" noise, is heard. Sometimes, however, the office suction pipes are partially blocked by debris, resulting in a reduction of the total office suction power. When this happens, the assistant should attempt to concentrate all of the office suction power into the one HVE chairside suction outlet that the dentist is using by turning off the other HVE chairside suction outlets in the office. The assistant can block off other suctions in other operatories by turning them off at their handle or, if the handle is stiff or blocked, by placing a piece of cardboard or the plastic side of a used autoclave pouch over the suction opening to block it.

[FIGURE 3 OMITTED]

An HVE attachment may have a small square inlet next to the larger oval inlet. The square inlet allows some suction to exist if the larger inlet inadvertently suctions the patient's soft tissues. However, the extra square inlet reduces the force of the suction of the larger inlet because the suction power is divided among two suction inlets. If the assistant wants to concentrate the suction power into one inlet because the office suction has been weakened by debris in the office suction piping, the assistant can put the HVE attachment in the holder so that the side with the square inlet goes into the holder. This way, the side of the HVE attachment being used has only one inlet. The HVE holder should completely cover and seal the square inlet when the end of the HVE attachment with the square hole is placed into the HVE holder. Otherwise, the square inlet will be exposed and will leak suction power.

Cleaning and maintenance of suction pipes

After every procedure, the assistant should suction water into the suction for 15-20 seconds to prevent debris from adhering to the internal suction piping. Hopefully the suction tubes are long enough such that the HVE inlet can contact a sink faucet within the operatory to allow such flushing. Suctioning water immediately after a procedure washes away thin films of protein or saliva within the pipes while these films are still fresh and easily water-soluable, before they can dry within the pipes and begin to build up a coating of protein and biofilm.

It is especially important to flush the lines with water immediately after completion of a procedure that involves blood, such as extractions or unusually bloody scaling/ root planning procedures. Fresh blood that has not yet dried is easy to wash away with water, but blood that dries within suction piping can be difficult to remove.

Liquids that can be used to flush out suction lines include water, bleach solution, soap solution, cleaning fluids that are specifically designed for suction units and enzyme solutions. If an assistant mixes a powdered suction cleaner in water to make a cleaning solution, the assistant should ensure that there is no residual powder in the solution before using it to clean the suction lines, since the powder can clog the lines.

If the office suction strength is generally not optimal due to debris build-up, the suction pipes may need to be professionally cleaned. A plumber may attempt to blow pressurized air through the pipes to unblock them. Sometimes the HVE tubing itself needs to be cleaned out or replaced due to build-up of debris in the tubing. If the suction force at the chairside trap (when the chairside trap is uncapped) seems to be more powerful than the suction force at the HVE inlet (when the chairside trap is capped), then the HVE tubing itself may be blocked.

Inspecting and cleaning the chairside suction trap

The assistant should inspect the chairside disposable plastic suction trap daily (or whenever the chairside HVE suction seems weak) and remove any debris obstructing the tiny holes in the suction trap (Figure 3, above). The assistant should also clean out the trap after every procedure where a large piece of debris was suctioned into the trap, such as a piece of dry angle material, large pieces of broken teeth, chunks of amalgam, a piece of broken or cut up crown, or pieces of temporary teeth acrylic. When the trap is dry, it may be cleaned by scraping it with the tip of a flat-head screwdriver and tapping it upside down into an amalgam waste receptacle to loosen the amalgam particles. The screen holes may be rubbed with paper towel to help loosen debris. If it seems that too many screen holes are plugged up when the cleaned trap is held up to a light source, the plastic trap should be replaced.

During a procedure, the assistant should avoid suctioning things that are difficult to dissolve or wash away from the lines, such as prophy polish grit or gutta percha crumbs or points. Thin gutta percha points can pass vertically through the tiny holes in the trap screen, where they can enter the office suction pipes and become relatively inert pieces of debris.

If suctioned, unset amalgam can "smear" itself into the holes of the plastic screen of the chairside suction trap, helping to block the trap over time. Also, sometimes there is a dark gray glob or disc stuck to the inside of the cap that is used to cap the chairside suction trap. This is a chunk of amalgam that had become sucked into the chairside trap, mashed into the cap and eventually set hard (Figure 3, page 11). This amalgam can slightly obstruct the air rushing into the chairside trap and may contribute to slight reduction of the suction power, so it should be scraped off the cap using a flat-head screw-driver.

Removing obstructions that are lodged in the handle of the HVE suction

Sometimes a piece of cotton roll or a chunk of extracted tooth particle can be sucked into the HVE inlet and become lodged in the handle of the HVE suction, resulting in a sudden, large reduction in suction power. To remove the obstruction, the assistant should detach the handle from the HVE tubing, and then push a long, thin, stiff rod (like a pencil or the handle end of a mouth mirror) into the end of the HVE handle that normally attaches to the HVE tubing. This should dislodge the obstruction through the HVE inlet (Figure 4, above). After this is done, the instrument used to dislodge the obstruction should not be used for further treatment until it is re-sterilized because it is assumed that the inside of a suction tubing is a contaminated area.

[FIGURE 4 OMITTED]

If the HVE handle cannot be detached from the HVE tubing for purposes of removing an obstruction, the assistant should turn off the office suction from the main office suction switch (or remove the cap from the chairside trap to divert suction power from the suction tubing). This will remove suction force pulling the obstruction into the HVE handle. Then a cotton plier or hemostat is used through the HVE inlet to grab the cotton roll or tooth particle and move it out through the HVE inlet, ideally using head-mounted lighting to better see the obstruction.

If a piece of tooth cannot be removed through the HVE inlet and the HVE handle cannot be detached from the tubing, the assistant may attempt to ram the tooth into the HVE tubing by pushing a rod through the HVE inlet. This may break the tooth piece into multiple pieces that are small enough to pass through the suction tubing; these pieces will then get suctioned into the chairside trap, where they can be removed.

Acknowledgment: The author wishes to thank Candace El-Beblawy, RDA, for her assistance in taking photographs for this article.

References

(1.) Dietz ER. HVE tips: maximizing high-velocity suction. Dent Assist. 1988 Nov-Dec;57(6):4-6.

John D. Mamoun, DMD, is a 2003 graduate of the University of Medicine and Dentistry of New Jersey. He completed a one-year residency in Advanced Education in General Dentistry at the Eastman Dental Center, a division of the University of Rochester Medical School in Rochester, N.Y., and later earned his Fellowship from the Academy of General Dentistry. He is currently in private practice in Manalapan, N.J. Dr. Mamoun has published several articles in peer-reviewed dental journals and serves as a manuscript reviewer for General Dentistry, the journal of the Academy of General Dentistry. He is particularly interested in analyzing how the use of high-magnification loupes or microscopes in clinical practice can lead to improved diagnoses and treatments of dental problems.
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Title Annotation:Clinical
Author:Mamoun, John S.
Publication:The Dental Assistant
Date:Nov 1, 2011
Words:3612
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