From 15 September to 15 October 1991, 102 dentists practicing in a rur
al area of Germany provided information on 3375 composite resin fillin
gs. The purpose of this cross-sectional study was to record the reason
s for placement and replacement of composite resin restorations, inclu
ding any change of material when replacing a filling, and to register
the age of any failed restoration. First placements because of primary
caries were made in 50.6% of all cases; 49.4% were replacements of fa
iled restorations. Composite resins were used as a material for the fi
rst placement of a restoration in 19.2% of primary teeth and in 47.8%
of permanent teeth. More amalgams were replaced by composites than vic
e versa. Secondary caries was the most frequent reason for replacement
in permanent teeth and in restorations with less than four surfaces,
whereas fracture caused most failures in primary teeth and in fillings
with four surfaces. The median age of the replaced restorations was 4
3.5 months. Failed restorations with four surfaces had the lowest medi
an age.