Class II resin composite restoration Flashcards
Why are we using more composite?
Alleged health concerns with amalgam
Environmental concerns with amalgam
Demands of dental profession to use adhesive material that demands less invasive cavity prep
Px demand for tooth coloured restorations in posterior teeth
Px and cavity selection indications
Small carious lesions that allow conservative prep
Restorations in which appearance is important
Moderate sized class II restorations
Resotrations in pxs allergic to metals
Where unsupported enamel may be strengthened by RBC
not possible to obtain retention form for non-adhesive restoration
Contraindications
Pxs with high caries activity
Poor oral hygiene
Cavities or pxs for which adequate isolation not possible
Multiple large restorations with cuspal contacts
Pxs with bruxing and grinding habits
Pxs with allergies to consituents of RBC material or their bonding systems
Cavity margins that extend beyond enamel e.g. in deep proximal boxes
Time constraints - need time to do good RBC
Choice of composite
Load bearing
Material that is ‘packable’ - which one? There are 50 different brands available
Composites that have matrix of resin monomers containing high vol > 60% of inorganic filler particles are recommended for posterior use
Posterior composites usually hybrid materials i.e. mixture of filler particle size
How easy is it to use? Can it be adapted to floor/ walls of cavity without sticking to instruments?
Can it hold its shape without slumping? etc
Shade selection
Shade should be taken before isolation
Shade matching less of concern for posterior ad can be advantage to assist with finishing
Greater accuracy by applying test composite 1st and cured
Lighter shades cure more readily than darker shades
Main aim of cavity prep
Remove diseased tooth only
Access should be limited to visualise the caries
Remove carious tooth tissue and / or any previous restoration to permit access for instruments
Why do we want to preserve enamel at cavity margins?
Especially cervical floor
Bond strengths greater for enamel than dentine
Where should interproximal boxes be extended to?
Just past contact point cervically to allow complete caries removal
Aid matrix placement
Permit caries diagnosis
Vertical box margins may be left in contact if this does not compromise matrix placement
Are occlusal dovetails necessary?
Not necessary to prevent displacement in an interproximal direction
Bevelling
Not recommended occlusally as this may result in thin margin of composite which could be prone to fracture under occlusal load
Proximally recommended by some to optimise marginal seal
-care needed not to damage adjacent teeth
Loups
Magnifying loupes will help with minimal prep of caries removal
Covering of peripheral stains/ amalgam as this can show through composite
Occulsal considerations
Access occlusal relationship preoperatively
Ideally cavity should be designed with occlusal contact on enamel rather than restoration where possible
Cavity should be designed to avoid heavy loading/ contacts at its margins
Asses extent of caries before making final decision on appropriateness of RBC
Clinicians ability to diagnose and remove caries accurately
Cervical margin should not be bevelled as this could result in loss of remaining cervical enamel/ moisture control and finishing more difficult
Check adjacent tooth for caries - if present it may be restored by direct access
Matrices
Achieving tight contact - major difficulties in placing satisfactory RBC as with packing does not push out matrix in same way as amalgam
Pre-wedging can push apart tooth to be treated and returns when resotration completed establishing good contact
Ortho separators placed 3-5 days prior may help
Types of matrices
Sectional matrices and separation rings
Circumferential matrix systems
Sectional matrices and separation rings
Give good contact areas
Various sizes available
Circumferential matrix systems
Single use systems e.g. Siqveland / Omnimatrix
Metal and clear
Clear ones difficult to insert through contact area compared to metal types
Cannot be burnished
Main advantage with clear is light-curing
Acid etch
Cavity must be clean
Bonding
Read manufacturers instructions
Use small increments for insertion and polymerisation - helps reuduce shrinkage
Increments decrease stress
-C-factor ratio: ratio of bonded to free cavity surface
Basic olique-layering technique
For cusp build up/ separate dentine and enamel build up/ and or using index
e. g. use of silicone putty to record morphology accurately prior to prep
- when applying final increments to composite the index is seated over unset material to recreate pattern
Bulk fill composites
New systems allow high filled composites to be placed using a sonic device in order to change composite viscosity to allow flow
> adaption
Low polymerisation shrinkage
Better aesthetics
Better seal
Sonicfill2-Kerr, Surefil SDR, Tetric Evo Ceram bulk fill
Expensive
Light curing
Light tip should be placed close
Lighter shades will cure more readily than darker shades
Light units should be monitored regularly
Care must be taken to prevent premature polymerisation by overhead chair light
Finishing and polishing
Micro-fine diamond burs with water coolant
Occlusion should be checked so that light contact is obtained in inter-cuspal position
Composite finishing systems used e.g. soflex discs in correct order
Impregnated rubber points and 50 micron aluminium oxide pastes
Surface glazes can be applied e.g. unfilled polymers/ staining techniques
Sequence
Diagnosis –> pre-occlusal record –> cavity prep –> isolation/ matrix/ wedge –> restoration –> finish and polishing and check occlusion
