essay 28 - fabrication of class V composite restorations - stages, instruments, specifics, matrix systems

specifics for class V restorations

1. location - cervical third of tooth - often crossing the cementoenamel junction (CEJ) onto root dentin or cementum

2. margins - one or more margins may be on dentin or cementum, which does not bond as predictably as enamel

3. moisture control - critical due to proximity to gingiva, contamination from saliva, sulcular fluid or blood is common

4. retention - primarily relies on adhesion, but mechanical undercuts or grooves may be needed in sclerotic dentin

5. tooth flexure - flexural forces at the cervical area (abfraction) demand flexible restorative material such as microfill composites or those with low modulus of elasticity

stages in fabrication of class V restorations

1. diagnosis and shade selection

• evaluate etiology (caries vs non-carious cervical lesions)

• select shade before isolation, under natural light; cervical enamel is usually darker, so multiple shades may be used

2. anaesthetic and isolation

• topical or local anaesthesia may be necessary due to dentinal sensitivity

• isolation is essential: rubber dams are preferred but often challenging in this area

— alternatives: cotton rolls, gingival retraction cord, teflon tape, retraction paste

3. tooth preparation

• for carious lesion: remove soft infected dentin, round internal angles

• for non carious lesions (abrasion/erosion/abfraction): minimal or no prep. bevelling may or may not be done depending on aesthetics and margin location

— do not bevel root surfaces

• 0.5 mm bevel may be placed on enamel margin to increase surface area for bodning

4. etching and bonding

• etch enamel for 15 sec, dentin for 10 sec

• rinse and gently air dry - dentin should remain moist

• apply primer and adhesive according to system used - light cure thoroughly

5. material placement

• microfill composites or flowable composites are often preferred due to flexibility and polishability

• insert in 1-2 mm increments, especially is the lesion is deep

• hand instruments are composite syringes can be used for placement

• light cure each increment thoroughly

6. contouring and finishing

• shape the restoration to blend smoothly into surrounding tooth structure

• use fine finishing burs, diamond points or abrasive disk

• finish margins carefully, especially at the gingival margin

7. polishing

• use rubber cusp, fine-grit polishers, or diamond-impregnated instruments

• achieve a smooth, glossy surface to reduce plaque accumulation and optimise aesthetics

instruments used

• shade guid

• etchant (phosphoric acid 35-37%)

• primer and adhesive system

• micro brushes or applicators

• composite instruments (plastic filling instruments, spatulas)

• curing light (LED recommended)

• finishing burs, disks, rubber polishers

• gingival retraction materials (cord, paste)

matrix systems for class V

1. Matric use in class V is limited and depends on:

• extent of lesion

• proximity to adjacent teeth

• need for gingival retraction

2. Matrix options

• mylar strip or teflon tape - for anterior teeth, helps contour facial class V restorations

• cervical matrix (transparent plastic mold) - adapts to cervical curve and helps in shaping and compressing the material

• Contour strip crown forms - can be adapted in special cases

• wedges are rarely needed unless proximal extension is significant

key clinical considerations

• isolation is critical for adhesive success

• use of flexible composites helps accommodate cervical flexure forces

• avoid over contouring to prevent plaque accumulation and gingival irritation

• blend shade and texture carefully, as class V restorations are often in visible areas