presentation1 retaction of gingiva

7/28/2019 Presentation1 Retaction of Gingiva

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Common errors of tooth preparation

The frequently erros which encounter the dentist during the toothpreparation can be observed in dental lab after pouring the model .These errors lead to inadequate reduction , which force the

technians to fabricate inadequate restorations

1- inadequate occlusal (incisal ) reduction

Result : lead to minimal interocclusal space (clearance)

- thin restorative material in occlusal surface (perforationor fracture of restoration )

- over bite ( high occlusion ) disorders inocclusion (T.M.J problems )

- non-anatomical form of occlusal surface


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2 lack of uniform reduction of or buccal surfaces

result : lead to over-bulky (overcountour) of restoration and non

esthetic appearance (restoration out of dental arch )

3 inadequate proximal reduction

result : lead to insufficient embrasure space ,which

cause pressure of restoration on dentalpapillae (gingivitis)

- divergent proximal walls

4 over-reduction of tooth structure (hieght and diameter of crown)

result : lead to loss of retention and resistance of restoration

- Pulp exposure(need R.C.T )


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5 undercuts creating on axial surface (mesio-distal andbucco-lingual surfaces) and lack of parallelism of abutments

result : lead to difficult seating of restoration (no seating)

6 inadequate reduction of margins (finish line)

result : bad impression of margins

- bad marginal integrity of restoration

7 excessive taper on the tooth preparation result : less retention and less resistance of restoration


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8 - SHARP ANGLES ON THE PREPARATIONresult : poorly crown fit

-may provide potential fracture stimulation for all ceramiccrowns

9 damage ( injury) of biologic width of periodontium(attached gingiva junctional epitheluim)

Result : periodontal complications (problems)

10 damage of countour of proximal surfaces of the

adjacent teethResult : leave space (gap) between restoration and adjacent

teeth , which lead to food impaction and its complications


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What to DoProblem

undercut within one surface

further reduction of wall

block out undercut


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taper walls moreopposing walls divergeundercut

What to DoProblem


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overtapered prep;loss of retention

and/oradd retentive grooveshoulder & bevelcreate

Problem What to Do


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finish line too heavy -walls are over-reduced

Create a bevel tofinish line

Problem What to Do


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finish line light(indefined)walls are slightlyr-reduced

increase axial reduction

Problem What to Do


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Tissue mangement in tooth preparation

It s the temporary retraction (pushing away) of the gingival

tissue from the tooth surface in the cervical area , which lead towidening of the gingival sulcus , to give more clear observationand operation in this area .

Indication

1- During preparation - For accurate position of finish line and its extention during

reduction , to avoid injury of gingiva and its bleeding

2- During impression taking

- To expose the marginal finish line to obtain completelyreproduction of this margins and to provide sufficient bulk of impression material at the margin to prevent its tear ordistoration upon removal from the mouth or pouring in stone

- to provide a clear and dry field , free from blood or gingivalfluid during impression taking


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Technique (methods) of gingival retraction

1- mechanical technique2- chemical technique

3- mechano-chemical technique

4- elctrosurgical technique- mechanical technique

for this technique used :

- copper band

- retraction cord

- orthodontic rubber band or waxed dental floss


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The commonly and widely used for mechano-chemicaltechnique is a retraction cord impregnated in

chemicalis

Retraction cord technique

It s a method of pressure packing the cord soaked orimpregnated in the chemicalis (Alum aluminuimchloride Ferric sulphate ) which lead to enlargementof the gingival sulcus , to control of fluids seeping

from the silcus and to stopping the gingival bleeding(hemostasis )


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Procedure

- prepared teeth are dried and isolated with cotton rolls

- saliva evacuators are placed (saliva suction)

- cut enough piece of cord length to encircle the toothopproximately 5cm

- cord is dipped in chemicalis (25% alumium chloride ALCL3 solution in a dappen dish .

note there is in sale ready impregnated retraction cordas

- the retraction cord is looped around the tooth and heldtightly with the thumb and forefinger

- the cord is packed (pushed) into gingival sulcus

starting from the mesial surface then proceed to lingualor buccal and end at distal surface


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- the cord can be paked with special blunt instrument likeFischer packing instrument or DE plastic instrument .

The instrument should be angled slightly towards the rootto facilitate the subgingival placement of the cord .

- excess cord is cut off near the distal surface

- after 5 10 minutes , the cord should be removedslowly to avoid bleeding (the cord must be slightly moistbefore removal because removing dry cord from thesulcus can injure the epithelial lining of the gingiva

( note dry cord adhere to capillaris of epithelial gingiva)

- after cord removal , impression is taken (must be surethat the area is clean from bleeding )


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Placing retraction cord Cord is placed withretractedgingiva and

forming shoulder

Cord is removed andcompletely formed

shoulder

Impression withnegative details of

shoulder

Retraction cord(ultra-pack)

Cord packer


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2 technique by expa-syl

Excellent retraction . Physically displacestissue for superb marginal access.Safe. Minimal pressure required. Nodanger of rupturing epithelial attachment. Significant timesaving . Places quickly.

Comfortable. Much less time and forceneeded than with packing cord.

Haemostatic. Controls bleeding andcrevicular seepage.(from sulcus)


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Expasyl retraction Paste


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Chemical technique

Chemicalis are frequently used to enhance the retractionprocess and to control hemorrhage (bleeding) , andcommonly used in combination with retaction cord .

Experience has shown that are safe when the time of use not exceed 15minutesRequirements for chemicalis used with gingival retraction cord

- its should produce effective gingival displacement and

hemostasis- it should not cause any irreversable damage to the

gingival tissue .

- it should not have systemic side effects in the patient


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Chemicalis used in this technique

1- aluminum chloride (25% Alcl 3 solution hemodont )

2- alum solution (Aluminuim potassuim sulphate) ALK (So4)2

3- Ferric sulphate Fe 4 2(So 4 ) 3 ( ultrapack- astringent )

4- tannic Acid solution

5- Epinephrine 1/1000 (8% Racemic epinephrine )

Epinephrine is cause hemostasis and local constrictionwhich results in temporary gingival shrinkage but , itscontraindicated and not recommended to use ongingival tissue in patient with :-

- Cardiovascular disease (CVS) increased heart rate(tahycardia )


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- Hypertention elvation of blood pressure

- Diabetes

- Hyperthyroidism

- hypersensitivity to epinephrine (Allergy )


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Electro-surgical technique

This technique accomplished by electrosurgicalapparatus (units)

presentation1 retaction of gingiva

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