Adequate moisture control during restorative procedures is one of the most important duties of the dental nurse. Control of moisture – from saliva, blood or instrument cooling sprays – is necessary for the following reasons.
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To protect the patient’s airway from fluid inhalation, especially as the majority of procedures are carried out with the patient lying flat back in the dental chair (supine position).•
To ensure the patient is comfortable during treatment – so that they do not have a mouth full of fluids while lying in the supine position during dental treatment.•
To allow the dentist good visibility to the treatment area, therefore avoiding inadvertent patient injury by catching the soft tissues or the wrong tooth with the drill.•
To allow the restorative materials to set correctly, without moisture contamination.•
To allow the adhesion of cements and linings to the tooth, without moisture contamination.•
To avoid the uncontrolled loss of materials from the cavity during use, such as acid etchant which can burn the soft tissues.The following methods are used to control moisture.
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High-speed suction.•
Low-speed suction.•
Use of absorbent materials – cotton wool rolls, cotton wool pledgets and oral inserts such as a‘Dryguard’.
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Use of rubber dam.•
Compressed air drying, using the triple syringe (3 in 1) of the dental unit.High-speed and low-speed suction
This is provided by either high-speed aspiration (suction), for fast removal of moisture during drilling, or low-speed aspiration for continual moisture control without sucking at the soft tissues.
In the case of high-speed suction, the dental nurse uses a wide-bore aspirator connected to the suction unit to rapidly remove fluids, blood and debris from the treatment area. This prevents the patient from choking, as well as emptying the oral cavity of volumes of fluid that would be uncom- fortable for the patient to hold without feeling the need to spit out. With low-speed aspiration, the patient holds a saliva ejector attached to the suction unit or aspirator to slowly but continually remove any fluids that have pooled in the floor of the mouth, so that the patient does not have to constantly swallow during the treatment. Many different types of ejector are used but those with
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a flange to keep the tongue away from the treatment area are particularly helpful. The dental nurse may also use the high-speed aspirator tube as a soft tissue retractor. Examples of aspirators and ejectors are shown in Figure 15.4.
Absorbent materials
Cotton wool rolls or absorbent pads are placed in the buccal or lingual sulcus to absorb saliva and keep the soft tissues away from the teeth. Cotton wool pledgets are used to dab the actual cavity dry, while excessive saliva contamination can be prevented by placing a ‘Dryguard’ over the parotid salivary gland duct. These pads contain an absorbent material similar to that used in babies’
nappies, and can retain considerable volumes of fluid. The cavity itself can be further dried by blowing it with compressed air from the triple syringe of the dental unit. Examples of some of these materials are shown in Figure 15.5.
Rubber dam
This is the best method of moisture control of all and the various components are shown in Figure 15.6.
A rubber dam is a thin sheet of latex rubber or vinyl material which is placed over a tooth to isolate it from the rest of the mouth. A rubber dam punch is used to punch a small hole in the rubber sheet, which is then fitted on so that the tooth projects through the hole. The rubber dam is kept in place by a rubber dam clamp which is fixed on the tooth with rubber dam clamp forceps. Finally a rubber dam frame is used to support the sheet while in use, so that it remains taut and maintains a clear visual field. A napkin is placed between the patient’s chin and the rubber to make it more comfortable and a saliva ejector may be provided to remove any pooled saliva. Dental floss or an additional piece of rubber dam material is used to work the sheet between the teeth.
A rubber dam may be applied to any number of teeth. It enables the operator to keep a tooth dry and maintain an uncontaminated field during dental treatment, and prevents pieces of filling material, debris or small instruments falling into the patient’s mouth.
This moisture control technique is more comfortable for patients as it prevents water spray or irrigation fluids entering the mouth, and far better for the dentist, as it improves access and visibility by keeping the tongue, lips and cheek out of the way. It also helps prevent cross-infection of patients and chairside staff, by minimising the aerosol of infected debris spread by the use of compressed air and water spray.
Figure 15.4 Aspirator and ejector tips.
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Figure 15.6 Rubber dam instruments. (a) Rubber dam. (b) Rubber dam punch. (c) Rubber dam clamp forceps. (d) Rubber dam frame. (e) Premolar clamp. (f) Incisor (butterfly) clamp. (g) Molar clamp.
(a)
(b)
(c)
(d) (e) (f) (g)
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The two main uses of a rubber dam are:
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in root canal therapy (endodontic treatment), to maintain a sterile field and prevent inhalation or the swallowing of small instruments•
during the insertion of fillings (especially composites and glass ionomers) to avoid their failure due to saliva contamination.Ideally, a rubber dam should be used for all fillings but most operators consider it too time- consuming for routine use in all procedures except endodontics. The technique is also not well tolerated by every patient.