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Moisture control of the operative field
Operative dentistry (ODC401)
Nahda University
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MOISTURE CONTROL
OF THE OPERATIVE FIELD
Operative Dentistry cannot be properly executed unless the moisture in the mouth is properly controlled. Objective: Maintain an environment that keeps the operating field free of excess water, saliva, blood, tooth fragments, and excess dental materials. Sources of moisture in the clinical environment : 1. Saliva, from salivary glands. (Parotid, submandibular, sublingual). 2. Blood, from inflamed gingival tissues or iatrogenic damage. Gingival crevicular fluid from inflamed gingival tissues 3. Water/dental materials, from coolant with rotary instrumentation, water from triplex syringe and materials we may use during treatment (eg. etchants, irrigant solutions, restorative debris). Reasons for moisture control: 1. Operating efficiency: Moisture control is essential for the convenience of both the dentist and patient. Excessive moisture is unpleasant for patient and complicates the work of the dentist, especially when high-speed handpiece is used with air-water coolant. Also, chair-time is wasted by frequent rinsing and expectorating. 2. Access and visibility: Moisture control is important during inspection of teeth for detection of caries or other defects. Visual diagnosis of caries in the form of cavitations, discoloration, or incipient lesion (white spot), is best achieved under dry conditions. The presence of water or saliva distorts vision and alters the reflective characteristics of the surface.
Moisture control is also required for inspection of cavities during cavity preparation. Saliva, debris, or hemorrhage at gingival margins may obscure cavities during preparation. Some field isolation methods involve maintaining an open mouth and depressing or retracting the gingival tissues, tongue, lips and cheeks, thus providing maximum exposure of operating site. 3. Best use of materials: Moisture control is essential for proper adaptation of restorative materials. Amalgam does not achieve its properties if used in a wet field. Moisture contamination of zinc-containing amalgam will result in blistering of the surface and postoperative hypersensitivity due to delayed expansion. Bonding to enamel and dentin is unpredictable if tooth substrate is contaminated with saliva , blood or other oral fluids. Also, moisture and blood must be excluded during impression taking and cementation of inlays. Moisture control is crucial in preventive measures such as topical application of gel or solution fluoride or fissure sealant. 4. Asepsis: Moisture control helps in infection control to protect dentist and personnel, as splattering of saliva and oral fluids is prevented or reduced. Moisture control is strongly recommended during caries excavation if pulp exposure is expected, with subsequent pulp capping procedures. 5. Harm prevention : Isolation of the operative field is important to provide safe treatment to the patient. Restorative debris, castings or small instruments may be aspirated or swallowed if proper isolation is not performed. It also, protects soft tissue from accidental damage during preparation or restorative procedure.
obstruct operator’s vision or access nor pull the coolant away from the preparation site. Washed field technique Combined water or air-water coolant and high-volume suction during high-speed cutting procedure. Advantages:
- Tooth and restorative material cuttings as well as other debris are removed from the operating site.
- There is no dehydration of the oral tissues.
- The patient experiences less pain and does not need anesthesia.
- Pauses that are sometimes annoying and time consuming are eliminated.
- Improves access and visibility
- Quadrant dentistry can be easily performed. Types of high-volume suction tips:
- Oral evacuation tips
- Surgical suction tips
- Much smaller in circumference
- Made of stainless steel
- Operative suction tips
- Designed with a straight or slight angle in the middle.
- Beveled working end.
- Made of durable plastic or stainless steel.
A: Oral evacuation tips, B: Surgical suction tips, C: Operative suction tips b. Low-volume suction (saliva ejector): Saliva ejector consists of a metal or plastic tube of about 6 mm diameter to aspirate saliva and small quantities of water from the floor of the mouth. It is quite unsuitable to aspirate large volume of fluids. It hangs in the patient mouth and does not need to be held by an assistant. It should be positioned in the floor of the mouth in an area less likely to interfere with operator’s movements, access and visibility. It can be used during cavity preparation, when evacuating small amounts of moisture is required, and also during restorative procedures. It is cheap (disposable) and easy to use but cannot be used to aspirate solids (e. fragments of dental materials). To prevent soft tissue irritation the saliva ejector tip must be:
- Smooth, made of non-irritating material
- Designed or shaped to prevent tissue in floor of the mouth from being aspirated into it. A piece of gauze can be tied around it or placed in the floor of the mouth to
2. Absorbent materials: Absorbent materials such as cotton rolls, gauze, sponges, and absorbent pads, are manufactured in different sizes and shapes. They should be placed in relation to salivary gland ducts for short term control of saliva and moisture provided that they are replaced before they become saturated. They are used when absolute dryness is not required as in examination, topical fluoride application, polishing, preparing for impression procedures and cementing inlays. Absorbents can be used in conjunction with other methods, such as saliva ejectors during operative procedures. For the isolation of upper posterior teeth, a cotton roll should be placed opposite to the opening the parotid duct to absorb saliva as it emerges. Also, an absorbent pad (parotid shield), which is triangular in shape with rounded corners, can be placed to fit into vestibule of the molar teeth. For isolation of the lower posterior teeth, a cotton roll in the upper buccal sulcus, and an additional roll in the lower buccal sulcus should be used in combination with the use of saliva ejector or additional cotton roll in the floor of the mouth. For isolation of anterior teeth, a halved gauze sponge twisted in the labial sulcus is feasible, or cotton rolls might be used. Cotton rolls should not cross the midline anteriorly, as it might be dislodged by frenum attachment.
Parotid shield
If the work is finished and the cotton rolls are still dry and adherent to oral mucosa, they should be moistened before removal. Otherwise, tearing away of surface layer of the epithelium may occur resulting in pain and ulceration.
Cotton rolls and cotton pads Cotton roll holder A device that holds cotton rolls in position. Advantage: Facilitates access and visibility, as the cheeks and tongue are slightly retracted. Disadvantage: inconvenient and time consuming, as it is necessary to remove the appliance from the mouth to change the cotton rolls.
Cotton roll holder 3. Rubber Dam: The rubber dam is used to define the operating field by isolating one or more teeth from the oral environment. When the rubber dam is used, many procedures are facilitated because dryness is ensured during preparation and restoration. Also there are fewer interruptions to replace cotton rolls to maintain isolation. When excavating a deep carious lesion expecting pulp exposure, use of rubber dam is strongly recommended to prevent pulpal infection by oral fluids. Saliva ejector and/or high
dam can be placed in 3-5 minutes, which is the approximate time required for the onset of anesthesia.
- Patient objection; patient may feel discomfort or phobic. However, after dam is applied most patients are relaxed knowing that water spray and debris are isolated from them during procedure.
Rubber dam
Conditions that may preclude the use of Rubber Dam: - Teeth that have not erupted sufficiently to support a retainer - Some third permanent molars - Extremely malpositioned teeth - Asthmatic patients may not tolerate the rubber dam if breathing through the nose is difficult - Mouth breathers - Patients with latex allergy Recent innovations:
- Recently a new type of rubber dam was introduced to provide isolation and retraction of the patients’ cheeks and lips with optimal visibility and accessibility and optimal patient comfort. (e.g, Optradam)
- Another product is a rubber retractor used to retract patients’ soft tissue (e.g)
(A) ( B)
(C)
A: optidam, B: optradam, C: optragate
4. Compressed air (Air-water syringe): Air-water syringe (triple-way syringe) (Fig. 6) is used during examination and during operative procedures. It is used in conjunction with other isolation means to ensure dryness of the cavity. Excessive air drying of cavities can cause dehydration, hypersensitivity and pulpal damage. Only short blasts from air syringe are used to ensure dry but not dehydrated cavity.
Air water syringe
Advantages:
- Improves access and visibility by controlling gingival seepage, hemorrhage and at the same time retract the gingival tissues
- Prevents trauma to gingival tissues during cavity preparation
- Restricts excess restorative material from gingival crevice Disadvantages:
- Can cause gingival damage if not inserted correctly
Retraction cord
Recent innovations:
- Chemical paste is available to control gingival bleeding only without causing gingival retraction.
- Another chemical paste was introduced to the market to control gingival bleeding and retract gingival tissues. It is easier and faster than in application than retraction cord. (e. Expasyl)
Chemical paste to control gingival bleeding
Expasyl
7. Electrosurgery It uses of high frequency electric current to incise/coagulate tissues. It can be used to access subgingival caries or control small amounts of bleeding. However, it can cause tissue damage if not used properly. 8. Laser: Soft lasers (Diode lasers) can be used for gingival troughing prior to taking impressions, gingival excision or esthetic crown lengthening procedures. In addition, they provide adequate hemostasis.
Moisture control of the operative field
Course: Operative dentistry (ODC401)
University: Nahda University
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