Method: From digital patient files, data from 87.454 direct restorations were collected, placed between January 2002 and December 2011. The following data were retrieved: Gender, age of the patient, operator, date of placement of the restoration, tooth type, nr. of surfaces, used material (composite, amalgam and glass-ionomer cement), date of the last check up and when applicable, date and type of intervention. Tooth extraction, endodontic treatment and placement of a new restoration including the same surfaces as the existing restoration, were considered as failure. Placement of a crown was not considered as failure, but resulted in censoring of observation time. Kaplan Meier statistics was used for survival analyses and a Cox-1 regression was used to investigate the influence of variables on the survival (p<0.05).
Result: Annual Failure Rates varied between operators from 3.9% to 6.6% (p<0.05). Results of the Cox regression, with hazard ratios and p-values of other main variables are mentioned in the table
Factor |
Hazard Ratio |
p-value |
95% BI (Min) |
95% BI (Max) |
Age |
1,009 |
<0,001 |
1,01 |
1,01 |
Gender (f) |
1,077 |
<0,001 |
1,03 |
1,12 |
Jaw (lower) |
1,040 |
0.03 |
1,00 |
1,08 |
2-surface (1) |
1,047 |
0.02 |
1,01 |
1,09 |
3-surface (1) |
1,249 |
<0,001 |
1,19 |
1,31 |
4-surface (1) |
1,285 |
<0,001 |
1,20 |
1,38 |
Composite (Amal) |
0.726 |
<0,001 |
0.67 |
0.78 |
Glass-ionomer (Amal) |
1,511 |
<0,001 |
1,38 |
1,66 |
Conclusion: Composite showed a higher and glass-ionomer restorations a lower survival compare to amalgam restorations. Moreover, age of the patient, gender, jaw, nr. of surfaces and operator significantly influenced survival of direct restoration in this general dental practice.