3. Class IV Restorations

Define a Class IV

Affects a proximal surface on an anterior tooth that involves the incisal edge

Etiology of Class II

Caries, Trauma, defective restorations

• Coronal fractures of permanent ________ represent 18-22% of all traumas to dental hard tissues, of these 96% involve ________ ________.

• Caries- induced Class IV are usually the result of a large class ___ that has reached the _______ ______.

• Coronal fractures of permanent incisors represent 18-22% of all traumas to dental hard tissues, of these 96% involve maxillary incisors.

• Caries- induced Class IV are usually the result of a large class III that has reached the incisal edge.

Disadvantages of Composite Resin

• Polymerization shrinkage

• Isolation and proper bonding required

• Less resistant to wear than ceramics

• Marginal staining

• Edge chipping on high stress areas

Advantages of Resin Composite

• Instant gratification

• Minimally invasive

• Good esthetics

• Acceptable longevity

• Easy to repair

• Low cost

Explain the Layering technique

Technique used for restoring a class IV where you layer enamel, then dentin, then enamel to restore the natural look of the tooth

Used for a more natural look

Fluorescence and Opalescence

Fluorescence is the brightness while opalescence is the white/blue translucency of a material

Silicone Matrix

• Used before to get a mold to use to shape the restoration

• Facilitates layering technique

• Minimal finishing needed

• Provides framework

Color selection

• Very important for these cases due to restoration being facial

• Patient must be wearing neutral colors

• Teeth must be cleaned

• Shade should be taken before rubber dam is on

• Point light away from patient

• Put a bit of composite on the tooth and cure it to know the true shade

When mixing base and catalyst of putty, do not wear what kind of gloves because they prevent hardening

latex gloves

Steps for the silicone matrix

• 1. Mix one scoop of base with one scoop of catalyst

• Mold putty to the tooth, making sure it does not cover the incisal edge

When cutting the tooth for the restoration, you are gonna cut where

Above the gingival contact to 2/3rd of the incisal edge

Beveling

• Purpose

• How is it done

• For aesthetic purposes only

• In a straight or preferably scalloped wavy motion taking 1-2 mm in thickness gingivo-incisally and 0.5mm facio-lingually

Steps for Restoring

1. Isolate with rubber dam

2. Check that silicone matrix fits properly

3. Etch, prime, bond beyond the prepared/ beveled surface

   • Place mylar strip to protect the adjacent teeth from the etch

4. Create lingual shelf by placing composite beyond the fracture so we can attach the matrix to the tooth

   • CANNOT TOUCH ADJACENT TOOTH!

5. Place on tooth and cure so your matrix is attached

6. Add 2 more layers, making sure you are forming the contact on the middle (dentin) layer

   • Make sure you check from incisal view to make sure you have the right anatomy

7. Make sure to push against bevel and form anatomy

8. Close contact using pull-through technique if open

9. Use so-flex strip to polish any roughness on the interproximal area

10. Finish and polish using carbide burs, enhancer cup and jiffy brush

    • Round football for lingual and evening out the restoration

    • Fine pointy burs to give the anatomy of the 3 developmental lobes

Pull-through technique steps

1. Place mylar strip

2. Place composite where the contact is supposed to be

3. Pull mylar strip in the disto-lingual direction