Longevity of restorations

Question 1

Survival of AR vs survival of CR

Answer 1

AR 1.5-2x longer, difference more significant in high caries risk groups. Minimal difference in low caries risk groups

Question 2

Describe process of degradation of adhesive bond at CR-tooth interface

Answer 2

Biofilm attaches via binding of gp340 protein from salivary pellicle. S Mutans is recruited to the surface

Bacteria produces lactic acid, which demineralises the hydroxyapatite, and promotes hydrolysis of adhesive

Esterases are also secreted, further hydrolysing the adhesive polymer. Soft underlying collagenous dentinal matrix is exposed, allowing further infiltration by pathogenic biofilm. There is further breakdown of the CR-tooth interface

Question 3

What are some factors that affect the longevity of restorations

Answer 3

Biological and clinician factors

Biological factors:
Patient factors such as fluoride exposure, caries status, xerostomia, diet, socioeconomic status, oral hygiene, age, genetics (MMP activity)

Tooth factors such as cavity design, location of tooth, presence of denture, tooth quality, occlusal load

Clinician factors eg technical skills

Question 4

Success of repair of restorations that fail due to fracture vs due to caries

Answer 4

Failure due to caries more successful repair vs failure due to fracture