composite restorations

Question 1

What is a composite restoration?

Answer 1

Complex materials where 2+ distinct, structurally complementary substances, typically ceramics, glasses and polymers, combine to produce structural/functional properties not present in any individual component

Question 2

What is the composition of composite?

Answer 2

25% resin matrix- monomer (TEGDMA, BisGMA, UDMA), photoinitiator (camphorquinone), accelerator (4-dimethylaminobenzoate ester), stabiliser (butilated hydroxytoluene) and inhibitor (2-hydroxy-4-methoxybenzophenone)

75% filler- silane treated silica

Question 3

What are some composites that report to show reduced polymerisation shrinkage?

Answer 3

Ormocers- 3D linked inorganic organic copolymers (+ no residual monomers so enhanced biocompatiblity) (higher packing ability than normal)

Siloranes- cationic initiation process to polymerise- reduces stresses

Question 4

How are composite resins classified?

Answer 4

Initiation techniques- heat, self, light, dual

Filler size- macro filled, microfilmed, nanofilled, hybrid

Viscosity- flowable, packable

Clinical application- direct, indirect

Question 5

What are the advantages?

Answer 5

Aesthetic 
Binds to tooth structure
Tooth sparing prep
Less costly and more conservative 
Repairablity
Doesn’t involve mercury
Lack of corrosion

Question 6

What are the disadvantages?

Answer 6

Polymerisation shrinkage (up to 3%) and micro leakage
Post operative sensitivity 
Secondary caries 
Low wear resistance
Technique sensitive
Adverse bio reactions

Question 7

What biological considerations are there?

Answer 7

Direct- oral lichenoid/allergic reactions

Dentine bonding agents- pulpal reactions

Indirect resin-based materials- allergic reaction, hand dermatitis in technicians

Question 8

What are the benefits of adhesion?

Answer 8

Strong attachment to tooth tissue
Resists shrinkage and minimises leakage
Tooth prep can be more conservative- no undercut
Supports weakened tooth structure
Optical integrity at cavity margins

Question 9

When do you use composite?

Answer 9

Restore caries
Repair fractures
Tooth wear rehabilitation 
Mask mild discolouration
Temp restoration for indirect veneer prep

Question 10

When don’t you use composite?

Answer 10

Insufficient tooth structure for bonding
Deep subgingival caries- moisture control not possible
Indirect might be better for severely damaged/heavily restored
Allergies

Question 11

What is the evidence?

Answer 11

Meta analysis- almost 400 clinical trials
Overall success rate- about 90% after 10 years
Main reason for replacement- bulk fractures/adjacent caries to proximal tooth