Introduction: This study evaluated the effects of eugenol –free temporary cement remnants on the
retentive strength of casting crowns luted via zinc phosphate and resin cement (Maxcem) to the
tooth structure.
Material and methods: 40 extracted human molars ware randomly divided into 2 groups. each
group was then divided into 2 subgroups and the teeth were paired so that the size of each tooth in
each subgroup was the same as a tooth in the other subgroups. 40 standardized Ni-cr complete
crowns were made on teeth prepared with a milling machine using conventional laboratory
techniques. For each adhesive system, in one subgroups a provisional restoration was cemented
using an eugenol –free temporary cement. Temporary crown was remained on the tooth structure
for an hour and then extracted and cement remnant was removed by an excavator. Then the casing
crowns were adhesively luted via zinc phosphate, adhesive resin(Maxcem) to prepared teeth. After
24h storage in distilled water, Retention was evaluated by measuring the tensile force required to
dislodge the crowns from tooth preparations with a universal testing machine after thermo cycling
(1500 cycles between 5c and 55c with 1- minute dwell times). The data were analyzed by means of
paired T-test and wilcoxon test in SPSS software version 11.5
Results: The analysis showed the mean retentive strength for 2 subgroups with and without prior
use of temporary cement in the maxcem group was 176 ± 55 and 274 ± 169 N, there was not a
significant difference between the 2 subgroups. (p value = 0.174). And the mean retentive strength
for 2 subgroups with and without prior use of temporary cement in the zincphosphate group was
257 ± 125 and 238 ± 135 N, there was not significan t difference between the 2 subgroups (p value
= 0.782).
Discussion: The use of an eugenol –free temporary cement does not alter the retentive strength of
casting restorations lutted to prepared teeth using the tested adhesive system, when temporary
cements are removed properly
