CONTROL OF MOISTURE Introduction The production of absorbed dryness by the exclusion of mouth sections and humidity from the operative field is essential to the correct performances of most operative procedures. The term oral environment refers to the following items which require proper control to prevent them. From interfering with the execution of any restorative procedures 1. Saliva 2. Moving organs, ie tongue 3. Lips & Check 4. The periodontium 5. The contacting teeth and restoration 6. The sulci, floor of the mouth and palate 7. Respiratory moisture With six major salivary glands producing saliva there must be a way to evacuate it either mechanically by the patient own swallowing mechanism or by chemically reducing its secretion. All these procedures are important because saliva may obstruct proper vision and access interfere with and detrimentally affect the setting and adaptability of restorative materials, modify or regale the effect of
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medicaments and may be sprayed with rotary instruments to propagate infection in the office atmosphere. 1. Moisture Control Moisture control refers to excluding sulcular fluid, saliva and gingival bleeding from the operative field. It also refers to preventing the handpiece spray and restorative debris from being swallowed or aspirated. The advantages of isolation are 1. Dry clean operating field 2. Access and visibility 3. Improved properties of dental materials 4. Protection of patient and operator 5. Operating efficiency Isolation of the operative fields involves several conceptual elements 1. Moisture control 2. Retraction 3. Harm prevention
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2. Retraction and Access The details of the restorative procedures cannot be managed without proper retraction and access. Thus provides maximal exposure of the operative site. It involves maintaining mouth opening and depressing or retracting the gingival tissue tongue lips and check. The rubber dam, mouth props, high volume evacuators, absorbants and retraction cord are used. Harm prevention An axiom taught to every member of the health profession is do not harm. An important consideration of isolating the operating field is preventing the patient from being harmed during the operation. Excessive saliva and hand piece spray can alarm the patient. Small instruments or debris can be swallowed. As with moisture control and retraction. The dam, section devices and absorbants play a role in harm prevention. Harm prevention is provided as such by the nannee in which these devices are used as by the devices themselves. Absorbants and Throat shield Absorbants such as cotton rolls and cellulose wafer are useful for short periods of isolation example for examination, polishing etc. and also for topical fluoride application. Absorbants are isolation alternative in cases where rubber dam application may not be possible. Especially along with profound anesthesia absorbants provide acceptable dryness for procedure such as impression taking and cementation. 3
The dental assistant mostly has the job of keeping dry cotton rolls in the mouth. They should be changed when saturated. Several commercial devices for holding cotton rolls in position are available. It is generally necessary to remove the holding appliance from the mouth to change the cotton rolls. This may be inconvenient and time consuming. An advantage of cotton roll holders is that the cheeks and tongues are slightly retracted from the teeth which enhances access and visibility, For maxillary teeth ďƒ˜
A medium sized cotton roll is placed in the adjacent vestibule.
For the mandibular teeth ďƒ˜
One medium sized roll in the vestibule and a larger one between the teeth and tongue. The teeth are then dried by short blasts from the air syringe. Cellulose wafers may be used to retract the check and provide
absorbancy. While removing these absorbants it may be necessary to moisten them using the all water syringe to prevent removal of the epithelium from the cheeks, floor of mouth and lips.
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Throat Shields These are indicated when small instruments are being used or indirect restoration placed. This is to prevent aspiration or swallowing of restoration. High volume evacuators and saliva ejectors When a high speed hand piece is used air water spray is supplied through the head of the hand piece to wash the operating site and to act as a coolant for the bur and the tooth. High volume evacuators are perferred for suctioning water and debris from the mouth because saliva ejectors remove water slowly and have little capacity for picking up solids. McWhecter in 1957 showed that evacuators generally would remove 5L of water in 2 seconds had 75% to 95% pickup of air and water and would remove 100% of solids during cavity cutting procedures. A practical test for the efficacy of the evacuator would be to keep it in 150ml of water it should suck it in 1 seconds. The tips for these may be 1. Plastic Disposable 2. Metallic auto cleavable The combined use of water spray and high volume evacuator has the following advantages. 1. Restorative and tooth debris are removed from the operating site.
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2. Access and visibility are improved. 3. No dehydration of oral tissues. 4. Time is saved as the pauses required for patient to spit and wash are eliminated. 5. Precious metals are readily salvaged. 6. Quadrant dentistry is facilitated. Precautions 1. The tip should be as near as possible to the tooth to be operated upon just distal to it. 2. It should not obstruct the operators view. 3. It should not be so close as to direct the water spray away from the rotary instrument. Saliva ejectors Most patient do not require saliva ejectors as salivary flow is greatly reduced when the operating site is profoundly anesthetized. The saliva ejector removes saliva that collects on the floor of the mouth. It is used in conjunctions with sponges cotton rolls and the rubber dam. It should be placed in an area least likely to interfere with the operators movements.
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The tip of the ejector must be smooth and made from a non-irritating material. Disposable inexpensive plastic ejectors that may be shaped by bending with the fingers are available. The ejector should be placed to prevent occluding its tip with tissue from the floor of mouth. Advantages can be summarized as the A – adequate access and visibility B – better patient protection and management C – control of moisture in operating field D – decreased operating time of rubber dam i.e. The Rubber Dam In 1864 S.C. Barmem a New York city dentist introduced the rubber dam into dentistry. Use of the rubber dam ensures appropriate dryness of the teeth and improves the quality of clinical restorative dentistry. The rubber dam is used to define the operating field by isolating one or more teeth from the oral environment. The dam eliminator saliva from the operating site and retracts the soft tissues. The advantages can be summarized as the Adequate access and visibility Better patient proportion and management Control of moisturing operating field Decreased operating time of rubber dam i.e.
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Advantages 1. Dry clean operating field rubber dam isolation is the preferred method of obtaining appropriate dryness. The time saved by operating in a clean contamination fill field with the good visibility more than compensate for the time spend in applying rubber dam. 2. Access and Visibility the rubber dam controls moisture and retracts lips cheek and tongue. It is dark coloured so it provides a dark non reflective background so access and visibility are greatly improved. The rubber dam prevents the agents from contacting the tissues. The teeth are in a dry field so there is a greater surface area to which solutions like fluoride etc. may be applied. The teeth become some what dehydrated has their permeability increases so fluoride uptake is more. The rubber dam protects the patient from aspirating or swallowing small instruments or debris associated with operative procedures. Immediate recovery of these materials is facilitated by the rubber dam. A properly applied rubber dam protects the soft tissue from irritating or distaste feel medicaments such as etchants. The dam also offers some protection from rotating burs and stones in addition the operator is protected from infections present in the patients mouth. The time required for patient to expectorate and rinse is saved. A certain amount of mouth opening is provided.
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Disadvantages 1. It cannot be used in a. Partially erupted teeth b. Some third molars c. Extremely malpositioned teeth. 2. In patient suffering with asthma it cant be used or if patient has preaching problems in such eases a hole may be cut in the palatal area thus facilitating breathing through the mouth. 3. Some patients may not be open to the idea of rubber dam if they are allergic to latex or if they have had an experience previously with an awkward or inept dental team. Armamentarium 1. Rubber dam sheets 2. Rubber dam holder 3. Rubber dam retainer 4. Rubber dam punch 5. Forceps 6. Napkin 7. Lubricant Rubber dam material It is available in rolls or sheets The advantage of material in rolls is that it can be cut to the desired shape whereas rolls are time saving. 9
The sheets may be 5x5 inch or 6x6 for Pedo. Sterile dam material is also available packed as individual sheets. The thickness available are : Thin
-
.006 inch
.15mm
Med
-
.008 inch
.2mm
Heavy
-
.010 inch
.25mm
Extra heavy
-
.012 inch
.3mm
Special heavy
-
.014 inch
.35mm
ď ś
Rubber dam material has a shiny and dull side
The thicker dam is available to retract the tissue its more resistant to tearing and especially recommended for Class V cavities in conjunction with a cervical retainers. The thinner materials have the advantage of passing through the contacts easier which is particularly helpful when they are tight. Rubber dam clamps Each clamp consists of 1. A jaw – on each side carrying the tooth attachment blades and wings. 2. A bow - which connects the 2 jaws and which should be elastically stainable and resistant enough to import a gripping force on the attaching blades against the teeth. According to the type and shape of the attaching blades clamps may be 1. 4 point contact blades i.e. blade portions of the jaw point inwards at each corner so that gripping forces are applied only on these dam points
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usually they contact the axial angles of the tooth and the attachments are very secure. Indications 1. Newly erupting teeth. Disadvantages Its possible traumatic effect or weakened undermined tooth structure. 2. Circum furencial contact blades The blade portion has noprojections and will contact the tooth surface evenly throughout its length. This type is less retentive but may also be less traumatic. It is used 1. When axial angles are lost or do not coincide with the corners of the 4patient contact damps. 2. When axial convexity of the tooth surface is sufficient for anchorage. Winged Clamps may also be classified as Wingless Those having wings can be attached to the rubber dam before application so the dam may be released after the clamp has engaged the tooth. Those are bulky and cannot be used in 3rd molars. The various clamps area Retracting anchoring clamps. 11
These are clamps especially designed to other functions besides anchoring the dam to the tooth. Examples: The No 212 S.S. White clamp was designed by Rew I Ferrier to isolate the gingival carious lesion. It is an effective gingival retractor and is especially used for cohesive gold restorations as the gingiva does not interfere with polishing of the restoration. The No 212 clamp is a double bow hatch type design that is also used for endodontic treatment of anterior teeth. The lingual opening is facilitated by the clamp design and there are finger rests on the compound lock that stabilizes the clamp before the clamp is used the grooves for the forceps should be deepened with a bur to prevent any movement. When it is placed because instability could cause damage to the gingiva or cementum. This damp can be modified to specifically fit narrow teeth lesions located more gingivally than normal and rotated teeth. They may also be sectioned and used for gingival isolation. The Schultz clamp series resembles the 212 clamp but are split in half facio lingually making it a gingivally retracting clamp with one bow only. Their use and attachment is very similar to that of 212 clamps but they are specially useful. Where a second bow cannot be accommodated due to a lack of space or limited accesses.
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Cervical retracting clamps may be single or double bowed, but the jaws and their blades are movable even after attaching the clamp to the tooth by moving these blades apically the gingiva can be retracted more apically and vice versa. Modified Clamps Clamps such as No W8A can be reshaped and adapted to almost any type of tooth and easily secured below the height of contour. The clamps most commonly modified are the ivory no W8A and the S.S. White No. 212. Ferrier clamps. These have broad application and can be fitted to the majority of operative cases. To expediate placing on rotated teeth the jaws may be modified by grinding suitable contour to the tip edge. The jaws may be bent for use on teeth where gingival access to lesions is difficult. This is done by heating the jaws to cherry red in a flame and then grasping the entire facial jaw and slightly bending it apically the procedure is repeated for the lingual jaw bending it occlusally. It is then carried and placed on the tooth. Next a ball burnisher is hooked onto one of the retainer notches and used to move the facial jaw gingivally to final position .5 to 1mm apical of the expected gingival margin care should be taken that the epithelial attachment is not harmed. The retainer is supported and locked into this position with red stick modeling compound which is placed between the bows and gingival embrasures placed between the bows and gingival embrasures.
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Anchors other than retainers 1.
A piece of cut rubber dam if wedged between contacting teeth can be used to anchor the dam especially proximal to the most anteriors isolated tooth.
2.
Inter ceptal rubber if it is of sufficient dimensions and is placed between intact teeth or properly restored teeth will be a very effective locking mechanism.
3.
Compound is used for immobilization of certain clamps by engaging their bows with adjacent teeth.
4.
Wooden wedges placed between teeth can be used to immobilize the interceptal rubber or alone to anchor the dam at its most anterior end. They are also used in isolating bridge pontics and abutments.
5.
A dental floss tape tied around a piece of cylindrical rubber, can be wrapped or tied around the axial surface to lock the dam apical to the rubber cylinder. This could be used when these are no apical convexities on the axial surfaces of a terminal anchoring tooth.
6.
Rental tape or floss is tied around the neck of the tooth to retain the dam apically it the gingival clest is at the same level on all tooth surfaces and will be in contact with dental floss or tape.
Rubber Dam Punch The punch is apricision instrument having a rotating metal table with 6 holes of varying sizes and a tapered sharp pointed plunger call should be
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exercised when changing from one hole to another the plunger should be centered in the cutting hole and the tip of the plunger should not be allowed to drag over the edges of the holes, otherwise the cutting quality of the punch will be ruined as evidenced by in completely cut holes which will tear open easily when spread during application over the retainer or tooth. Forceps Forceps all used to seat the cleanup around the tooth to hold the rubber dam in the mouth and tolerance the clamp. Cleanup placement requires good observation to prevent injury to the soft tissue and this is accomplished with contoured and fitted rubber dam forceps. The nose of the forceps can be refined to aid in securing the cleanup maintenance includes only lubrication and sterilization. Rubber dam holders There are a variety of holders for the rubber dam but their main objective is to keep the peripheries of the dam out of the mouth others objectives mouth. Others objectives are 1. To stretch the dam in 4 directions. 2. To retract check and lips. 3. To clear the field for further procedures They are classified as 1.
Strap type
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Which depends on the back of patient head for anchorage it should be attached to the dam at its corners and sides. From these attachments come belts which stretch and pull the rubber towards the occipital parts of the head eg. Wood burry holder. They may used an attached weight to keep the dam from wrinkling. 2.
Hanging frame holders may be
Metallic Plastic
3.
U shaped or ellipitical or rectangular with multiple prongs at their peripheries these prongs will equal the rubber dam, thus retracting both the dam and the musculature engaged by the dam. These are the most popular holders.
Advantages 1. Ease of application 2. Minimal contact of rubber with skin Disadvantage is that they may decrease the access. Napkins These are absorbant materials that are placed between the skin and rubber dam and has the following advantages. 1. Prevents contact of skin with rubber so reduces the allergic action is sensitive patients. 2. Absorbs saliva at the corners of the mouth. This prevents irritation and cracked facial tissue which results from prolonged moisture contact.
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3. Acts as a cusion. 4. Provides a convenient method of wiping the patients lips on removal of the dam. It ads to the comfort of the patient especially on long appointments. Lubricant A water soluble lubricant is applied in the areas of the punched holes. This facilitates the passing of the dam through proximal contacts. The lubricant may be commercially available but shaving cream or soap sherry are satisfactory substitutes. All of these agents are easily removable from the enamel surfaces after the dam application in order to prevent contamination and adaptation problems. Petroleum jelly is also used by some but leaves an in removable film, so it is not recommended. Template 1. A template may be used to mark the location of the holes. These templates may only serve as guide lines as the teeth may not be in their ideal places in all mouths. Another method is to place the area on the rubber dam to be marked on study models and mark them directly for punching.
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A this method is, the patient is asked to bite an a short of base plate wax which is then chilled and applied over the area to be punched and the teeth are marked with a pin penetrating the wax. Guidelines 2. Always isolate a minimum of 3 teeth except for root canal treatment where only one tooth should be isolated. 3. The distance between 2 holes is equal to the distance between center of one tooth to center of another measured at the level of gingival tissue. It the distance is more the dam wrinkles and causes folds if it is less it stretches and causes seepage. 4. For operations on anterior teeth canine to canine isolation is sufficient wedges may be placed distal to the canine and are adequate to retain the dam. 5. For class V lesions and usage of 212 clamp. The hole should be deviated 2-3mm away from the normal arch line facially or lingually depending on weather it is a facial or lingual lesion. 6. For a person with large upper lip the holes for anterior teeth should be more than an inch from the edge and vice versa. 7. For mandibular teeth the further posteriorly the anchor tooth the more dam material is required to come from behind the retainer over the upper lip.
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8. Heavier dams are used to isolate a class V lesion. 9. Thinner dams have greater elasticity so they require smaller holes. Attaching the dam to the teeth There are 4 ways 1.
Winged clamps attach the dam to the dam engaging projection the forceps are engaged in the dam holes. The clamp is placed on the tooth and pushed apically over the height of contour there, the clamp is then released from the forceps and the forceps is removed in an occlusal direction. After making sure of the stability of the clamp the dam holes are disengaged from the clamp wings and directed apical to the clamp components.
2.
A wingless clamp is attached to the anchor tooth. The hole for the anchor tooth in the rubber is then stretched on both sides laterally and slipped over the bow and jaws of the clamp and anchored apical to the clamp jaws.
3.
The dam hole is stretched over the tooth to be anchored and kept in place with finger pressure and then the clamp is placed.
4.
The dam can be attached to the bow of a wingless clamp by the edges of its anchor tooth hole then the clamp is placed and rubber is slipped apical to its jaws.
Rubber dam application Special rubber dam application
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1. Fixed bridge isolation
Indications 1. Restoration of an adjacent proximal surface. 2. Cervical restoration of an abutment tooth. Methods 1.
This type is done with no holes in place of the pontic. The dam is seated so that the rubber will actually be located occtusal to the abutment. Wedges are inserted interproximally between the pontics and the abutment tooth to retain the rubber apically softened compound is added to stabilize these wedges.
2.
This is similar to the first except a piece of pipe cleaner is used instead of wedges.
3.
The dam is stretched onto the teeth. A blunt curved suture needle with floss is threaded the hole for the anterior abutment and then under the anterior connector and back through the same hole on the lingual side. The needles direction is then reversed and it is passed from the lingual
side through the hole for 2nd bridge unit then under the same anterior connector and then through the hole of the 2nd bridge unit on the facial side. A square knot is tied with the free ends of the floss thereby pulling the dam material simply around the connector and into the gingival embreasure.
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Substitution of a retainer with a matrix A matrix can be applied instead of retainer to hold the rubber dam in place. The operator obtains access and visibility for insection of the alloy by reflecting the dam distally and occlusally over the mirror. Care must be taken not to stretch the dam so much that it is pulled away from the matrix permitting leakage around the tooth or slippage over the matrix. The matrix unlike the retainer has neither jaws or bow so the dam may slip unless dryness is maintained. Removal of Rubber dam Errors in application and removal 1. Off center arch form this may obstruct the patients nasal airway and may not even shield the complete oral cavity so foreign material may escape down the throat. 2. In appropriate distance between the holes a. Too small distance will lead to leakup. b. Too great distance will leads to a. Wrinkling b. Inadequate access and tissue retraction
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3. In appropriate retainer Retainer may be in appropriate by 1. Being two small when jaws are stretched it may break. 2. Being unstable on the anchor tooth. 3. Impinging on soft tissue. 4. Impinging on dam material. 4.
Sharp tips of a 212 retainer should be sufficiently dulled to prevent damaging the cementum in Class V lesions.
5.
Shredding or tearing dam should be avoided as this will lead to incomplete isolation.
Alternative isolation aids Retraction cord when properly applied can be used for isolation and retraction in the direct procedures of treatment of cervical lesions in facial veneering as well as in indirect veneers. The gingival retraction when moistened with a non caustic styptic may be placed in gingival sulcus to control sulailar seepage and or hemorrhage. Most brands are available with and without the voso constrictor epinephrine which acts to control sulculae fluids. A properly applied retraction cord, will improve access and visibility and help prevent abrasion of gingival tissue during cavity preparation.
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Antisalivary drugs The use of drugs in restorative dentistry to control salivation is rarely indicated and generally limited to atropine. Is with any drug the operator should be familiar with its indications contra indications and side effects. It is important to remember that atropine is contra indicated for nursing mothers and for patients with glaucoma. Some Anti histaminics like Hi receptor antagonists also cause dryness of mouth due to anti cholinergic action but they inhibit the action of local anesthesia so are contra indicated. Although several methods and devices are available to create a dry working field. The rubber dam is one of the most ideal the working field that is produced is in principle. In medicine, surgical procedures are done with controller operating field’s surrounded by aseptic environment. An attempt should be made in restorative dentistry to work only on clean teeth and on a patient who is under control. Control should mean not only the elimination of moisture but the elimination of humidity as well utilizing all the above mentioned measures.
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Contents 1. Introduction 2. Methods of Isolation 3. Rubber Dam 4. Drugs 5. Conclusion
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