COMPARISON OF THE RESISTANCE TO TRACTION FORCE IN CERAMIC METAL CROWNS BY USING TWO PROTOCOLS

Abstract

AIM Determine the difference in the tensile force needed to dislodge the metal ceramic crowns with collarless (CERAMIC
SHOULDER) on extracted natural teeth using two different protocols for preparing dental substrate and the same dual-cure
adhesive resin cement. MATERIALS AND METHODS: Thirty-five recently extracted for orthodontic indications were stored
by conservation protocols, of which thirty were prepared by the same operator and five teeth were machined on computerized
lathe to receive metal ceramic collar less crowns. The sample was distributed as follows: fifteen teeth for use cementing
preparation of dental substrate, fifteen teeth using cement without preparing the dental substrate and five teeth machined
for using unprepared cementing dental substrate. The sample was subjected in each group to force tensile eviction using
INSTRONR machine universal testing setting results for each comparison between them it was made and finally the type of
failure was determined in the cement (adhesive or cohesive) to each sample. Means and standard deviations were established,
the confidence level was set at 95% and the significance level of 5%. RESULTS: Measurement of adhesion strength of the
crown established that the tensile strength before eviction if had statistically significant difference (p <0.05) in at least two of
the three groups, specifically the SP group (control) and CP. This is obtained by applying the nonparametric Kruskal-Wallis
test. CONCLUSIONS: Within the limitations of this study it can be concluded that preparations near 15 degrees of cervical
convergence obtained to perform manually are suitable for resistance adequate traction crowns metal ceramics collarless
cemented with RelyX U200 3M ESPE.