Monday, January 5, 2009

Rubber Dam Application and Isolation of Operating Field in Conservative Dentistry

Rubber dam was introduced by S.C. Barnum in 1964.

Application of rubber dam is the most successful method of isolating the operating field.

Advantages

Dry clean operating field

Better access and visibility

Protection of Patient and Operator

Increased operating efficiency

Improves the properties of dental materials indirectly

Disadvantages

Time consumption

Objectionable to some patients

Unfavourable Conditions for Dam Placement

Insufficiently erupted teeth

Some third molars

Extremely malpositioned teeth

Some third molars

Asthmatic patients

Latex allergy

MATERIAL

Rubber dams are available in 5X5 inch and 6X6 inch sheets.

They available in 5 different thickness

Thin 0.15 mm (0.006 inch)
Medium 0.20 mm (0.008 inch)
Heavy 0.25 mm (0.0010 inch)
Extra Heavy 0.30 mm (0.012 inch)
Special Heavy 0.35 mm (0.014 inch)

The rubber dam has a shiny and a dull side.

A rubber dam holder ( frame) is used to secure the borders of rubber dam in stretched condition.

Young´s rubber dam holder is U shaped metal frame with small projections to hold the dam.

Rubber dam retainer or clamp is used to anchor the rubber dam to the most posterior tooth to be isolated.

It consists of four prongs and two jaws connected by a bow.

The prongs make four point contact with the tooth.

The jaws of the retainer should not extend beyond the mesial and distal line angles of the tooth.

Retainers are available with and without wings.

The functions of the wings -

1. To provide extra retraction of the rubber dam from the operating field

2. Allow the attachment of the dam to the retainer before placing it on the tooth.

The disadvantage of the wings is that it interferes with the placement of the matrix bands, band retainers and wedges.

Retainers are not required when isolating anterior teeth except in case of cervical retainer while dealing with class V cavities.

Rubber dam punch is used to make holes in the rubber dam. It has provisions for making holes of 6 different sizes.

Rubber dam luricants are used to lubricate the rubber for easy positioning.

Ideal rubber dam lubricants are water soluble lubricants like soap slurry and shaving cream apart from commercially available specific lubricants.

The corner of the mouth and lips should be protected by cocoa butter or petroleum jelly.

When operating on incisors and mesial surfaces of canines the isolation should extend from first premolar to first premolar.

When operating on canines the isolation field extends from first molar of the same side to the lateral incisor of the opposite side.

For premolars at least two teeth distal to the required tooth and lateral incisors on the opposite side on the opposite side are included.

For molars the isolation extends from the last available tooth to the lateral incisors of the opposite side.

For endodontic purpose only the tooth to be operated on is isolated.

The distance between the holes of rubber dam is 6.3 mm or ¼ inches.

The first hole in the maxillary arch should be punched for central incisor.

For the mandibular arch the first hole should be punched for the most posterior tooth that will receive the retainer.

For class V lesions the holes are punched slightly facial to the arch form. This compensates for the extension of the dam in cervical area.

If the thinner dam dam material is chosen the holes should be smaller because the thinner materials stretch more than the thicker ones.

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