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TOOTH SEPARATION. DEFINITION. “Process of separating the involved teeth slightly away from each other or bringing them closer to each other and / or changing their spatial position in one or more dimension”. Reasons for tooth separation. Examination Preparation of teeth
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DEFINITION “Process of separating the involved teeth slightly away from each other or bringing them closer to each other and / or changing their spatial position in one or more dimension”
Reasons for tooth separation • Examination • Preparation of teeth • Polishing of restoration • Matrix placement • Removal of foreign bodies • Repositioning of shifted teeth
Methods of tooth separation • Slow or delayed separation • Rapid or immediate separation
SLOW SEPARATION • Teeth are slowly and gradually shifted apart by inserting materials between the teeth • Usually takes long time – from several days to weeks Indications: • Tilted, drifted and rotated teeth
Advantages: • Tooth separation occurs without damage to periodontal ligament fibres Disadvantages: • Time consuming • May require many visits
Methods of achieving slow separation • Separating rubber rings or band • Rubber dam sheet • Ligature wire or copper wire • Gutta-percha sticks • Over sized temporary crowns • Fixed orthodontic appliances
RAPID TOOTH SEPARATION Advantages: • Quicker • More predictable results Disadvantage: • Chances of periodontal damage
Principles of rapid separation • Traction principle • Wedge principle
Traction principle • This principle uses mechanical devices which engages the proximal area of the tooth with holding arms. These holding arms are moved apart to create the separation between the contacting teeth. • Devices which works on this principle: 1. Ferrier double bow separator 2. Non- interfering true separator
Ferrier double bow separator • Has two bows • Each bow engages the proximal contact area of the tooth just gingival to contact area • ‘wrench’ system is used for turning the threaded bars, this helps in causing separation Adv: • Stabilization of separation throughout the operation • Separation is achieved at the expense of contacting teeth rather than one tooth Uses: Tooth preparation and finishing and polishing of class – III gold restoration
Non- interfering true separator • Non- interfering type rapid separator • Used where continuous stabilized separation is required Adv: • Separation can be increased or decreased after stabilization • Non – interfering in nature
WEDGE PRINCIPLE • A pointed wedge shaped mechanical device is inserted beneath the contact area of teeth, which in turn, produces the separation • Accomplished by two means: 1. Elliot separator 2. Wedges
Elliot separator • Also known as “crab claw” separator • Mechanical device consisting of - bow - two holding arms - tightening screws • Tooth separation should not be more than the thickness of the periodontal ligament, i.e. 0.2 to 0.5mm • Uses: examination and final polishing of proximal restoration
WEDGES • Devices preferred for rapid separation Classification: Basically wedges can be differentiated into: • Wooden • Plastic / polyester wedges. This can be further classified as: a) Preformed wedges b) Custom made wedges Eg: Orange wood stick, oak wood etc.
1) Medicated wedges Eg: Haemo wedges 2) Non-medicated wedges Eg: Orange wood stick I) Synthetic wedges Eg: Synthetic resins II) Natural wedges (Eg: Orange wood, Soft pine)
Depending upon the shape, they are classified as • Triangular (anatomic) wedges () (Triangular in cross section). • Round wedges (O) (Round in cross section)
Functions Of Wedge • Assure close adaptability of the matrix band to the tooth and prevent gingival overhang or cervical flash of material. • Define the gingival extent of the contact area as well as the facial and lingual embrasures, thereby assuring the health of the proximal periodontal tissues. • Occupy the space designated to be the gingival embrasure, preventing the restorative material from impinging on it, thus assuming proper health for the gingival inter dental papillae (col).
Help in rapid separation • Establish atraumatic retraction of the rubber dam and the gingiva • Assure the immobilization of the matrix band • Protect the interproximalgingiva from unexpected trauma. • Prevent the matrix band from springing open under pressure
Wooden wedges • Most commonly used • Absorb water and swell, thus stabilizing the matrix band and prevent impingement of the restorative material • Available in two shapes - triangular - round
Triangular wedge: is indicated when deep gingival extension of the proximal box is anticipated because the greatest cross sectional dimension of the wedge is at its base • Round toothpick wedge: Placed in the gingival embrasure protects the gingiva during proximal boxing. It is preferred with conservative proximal boxes because its wedging action is more occlusal (near the gingival margin) than with the triangular wedge
Plastic Wedges • Plastic wedges / resin wedges are transparent, thereby they can be used during placement of composite resin restorations as they allow visible light to pass through. • They can even be bent or moulded to the configuration of the col.
TECHNIQUE FOR PLACEMENT OF THE WEDGE According to Charbenaeu and Phillips, usually the wedge is inserted into the interdental space from the lingual side because of two reasons : • this is the wider of the embrasures. • handle of the matrix retainer comes in the way. According to Sturdevant, facial or lingual wedge placement depends on the operators judgement. (For example, if placement of the wedge from the buccal accomplishes better cervical closure of the band, then this direction of insertion should be selected). Moistening the wooden wedge by submersing it in water permits easier placement and tends to better secure its position
Length of the wedge • A customized wedge may be only 4-6 mm in length. • The wooden wedge should be approximately 5-6 mm long and should be trimmed for proper taper, thickness and width
WEDGING SYSTEMS Piggy back wedging • In this wedging system, if the wedge is significantly apical of the gingival margin, a second, usually smaller, wedge may be “piggy backed” on the first to wedge adequately the matrix against the margin. • useful in patients with recession of interproximal tissue level and / or if the proximal box is shallow gingivally
Double wedging system • Double wedging refers to inserting two wedges - one from the lingual and a second from the facial embrasure. • Two wedges help to ensure that the gingival corners of a wide proximal box can be properly condensed as well as to minimize gingival excess.
Wedge- wedgingsystem • Occasionally a concavity may be present on the proximal surface gingivally of the contact and extending as a fluting onto the root (eg. the mesial of the maxillary first premolar). A gingival margin located in this area will be similarly concave • To wedge a matrix band tight against such a margin a second pointed wedge can be inserted between the first wedge and the band