essay 34 - isolation of the operative field in endodontics - goals and purpose. Basic instruments and materials for isolation - types, characteristics. working techniques. isolation of teeth with destroyed crowns - methods for approaching the problem

what is isolation of operative field in endodontics

• the separation and protection of the tooth undergoing treatment from its surrounding oral environment - saliva, blood, gingival fluids, microorganisms and soft tissues

• Isolation can be achieved by rubber dam, cotton roll or cellulose water

advantages of isolation

• dry clean operating field

• improves access and visibility

• protection of patient and operator

• operating efficiency

disadvantage of isolation

• time consumption

• patient objection

• (rubber dam) cannot be used when : not erupted teeth, some third molars, malpositioned teeth, asthma, psychological reasons, latex allergy

goals and purpose of isolation

• moisture control - excluding sulcular fluid, saliva and gingival bleeding from the operating field . Prevention of handpiece spray and restorative debris from being swallowed by the patient

• Retraction and access - provide maximal exposure of the operating site and usually involves maintaining an open mouth and depressing or retracting gingival tissue, tongue, lips and cheek. For retraction and access we use rubber dam, high volume evacuator, absorbents, retraction cord and mouth prop

• Harm prevention - for patient comfort and safety as the handpiece spray can alrm the patient and soft tissues can be damaged accidentally

list the basic instruments and materials needed for isolation

• rubber dam material

• holder

• retainer

• punch

• retainer forceps

• rubber dam napkin

• lubricant

describe rubber dam material

• size = 5×5 inch, 6×6 inch

• sterile dam material is available packaged as individual sheets

• thickness = thin (0.15mm), medium (0.2mm), heavy (0.25mm), extra heavy (0.3mm) and special heavy (0.35mm)

• colour = dark colours are preferred for contrast, green and blue also available

• shiny side and dull side = dull side is less light reflective so is placed facing occlusal side of isolated teeth

• Thicker dam is more effective in retracting tissue and more resistant to tearing, while thinner dam passes through the contacts easier

• Dark, heavy 6×6 inch sheets are recommended

describe holder

• maintain the border of rubber dam in position

• the Young holder is a U shaped metal frame with small metal projections for securing the border of the rubber dam

describe retainer

• also known as clamp, consists of 4 prongs and 2 jaws connected by a bow

• used to anchor the dam to the most posterior tooth to be isolated. Also used to retract tissue

• Retainer should contact the tooth in 4 areas = 2 facial, 2 lingual, this 4 point contact prevents rocking or tilting of the retainer

• Jaws of retainer should not extend beyond mesial and distal line angles of the tooth

• wingless and winged retainers are available

• winged retainer has anterior and lateral wings which provide extra retraction of the rubber dam. Disadvantage is that the wings often interfere with placement of matrix bands, band retainers and wedges

• Bow of retainer should be tied with dental floss approx 30.5cm long before retainer is places in mouth

describe punch

• used to make round holes of different diameters (for tooth being operated to come out of the dam)

• precision instrument that has a rotating metal disk with 6 holes of different sizes and a tapered sharp pointed plunger

• Plunger is to be centred in cutting hold so that the edges of the holes are not at risk of being chipped by the plunger tip while it’s closed

describe retainer forceps

• used for placement and removal of retainer/clamp from the tooth

• ivory forceps are preferred as the dentist can apply direct pressure toward the gum

describe rubber dam napkin

• placed between rubber dam and patients skin

• prevents skin contact with rubber to reduce possibility of allergic reactions

• absorbs saliva seeping at corners of mouth

• acts as cushion and provides a convenient method of wiping the patients lips on removal of the dam

describe lubricant

• water soluble lubricant is applied in area of punched holes, facilitating in passing of dam septa through proximal contacts

• Applied in both sides of the dam in areas of punched holes

technique when positioning the rubber dam during isolation

1. positioning of rubber dam

• dental floss to check nature of contacts

• select clamp and try it in the mouth. secure clamp with dental floss to protect the patient from ingestion of clamp. If clam p comes off easily it should be changed. If it appears stable, insert it in the opening of the rubber sheet following the appropriate technique

• Place tooth in the centre of the dam, placing it asymmetrically with respect to the patients face. The more distal the tooth, the closer the opening must be to the centre of the rubber sheet. When the opening is asymmetrical to the patients face or in the centre of the dam, the metallic frame does not interfere with the X-ray machine

techniques for placing the rubber sheet

1. sheet with winged clamp and forceps, frame is last

• rubber sheet is punched

• rubber dam is stretched over the wings of the selected clamp

• assistant helps to position the dam and clamps in patient mouth

• forceps position the clamp around the tooth to be treated

• young frame is positioned to produced tension in the dam

• dam is slipped beneath the clamp wing on buccal side and same is done on lingual

• floss used to force dam through interproximal contacts

2. sheet with winged clamp, forceps and frame as a single unit

• dam with winged clamp stretched over Young’s frame

• clamp, dam and frame positioned in mouth as a single unit

3. clamp on tooth, then rubber sheet and frame

• wingless clamp is placed around tooth

• the rubber sheet has been slid slowly below the clamp which is already in place

4. sheet on tooth, then clamp and frame

5. sheet with wingless clamp and forceps under the sheet

isolation of teeth with destroyed crowns - methods for approaching the problem

• crowded teeth - no room for clamps

— rubber dam is held in place by tucking two fragments under the distal contact points of the adjacent teeth. This creates mechanical retention by friction and interproximal contacts

• wingless clamps

— a wingless clamp is first positioned directly around the tooth, engaging the cervical region.

Then, the rubber dam sheet is stretched and slid below the clamp

• Cutting dam instead of flossing

— in situations where the interproximal contact is too tight of irregular, the dam cannot be passed through easily. Instead of forcing it and risking tearing, the dam is carefully cut and placed directly around the teeth, then secured with ligatures or wedges. This is especially useful during removal to avoid trauma or damage to the dam or gingiva

describe cotton roll and cellulose wafer isolation

• cotton rolls and cellulose wafers are absorbent materials used to control moisture in the oral cavity during dental procedures. They are especially useful when rubber dam isolation is impractical or not possible. Cotton rolls can be as effective as rubber dams in short procedures especially when combines with local anaesthesia and saliva ejector

— cotton rolls - cylindrical, absorbent rolls placed in the vestibular or lingual spaces

— cellulose wafers - flat, sponge-like absorbents that can sit on mucosa

— gauze sponges - flat pads used for blotting or packing

• maxillary posterior teeth = place cotton roll in vestibule adjacent to the teeth

• mandibular posterior teeth = place large cotton roll between tongue and teeth by ‘‘rolling’’ it into place. This helps to control saliva from sublingual glands

• Facial and lingual placement = proper positioning improves both moisture control and visibility

technique when using cotton roll and cellulose wafer isolation

• maxillary posterior teeth = place cotton roll in vestibule adjacent to the teeth

• mandibular posterior teeth = place large cotton roll between tongue and teeth by ‘‘rolling’’ it into place. This helps to control saliva from sublingual glands

• Facial and lingual placement = proper positioning improves both moisture control and visibility