Retention of cast posts cemented with zinc phosphate cement using different cementing techniques.
OBJECTIVE
This study compares the effect of different cementation techniques on the retention of cast posts and cores.


METHODS
Twenty-four extracted single rooted human teeth were used in this study. After routine preparation of the root canals, the canal space was enlarged with reamers. Direct post patterns were made with acrylic resin. Castings were fabricated using Ni-Cr-Mb alloy. Zinc phosphate cement was used as a luting agent using 4 different methods of cement introduction to the root canal space. This created 4 treatment groups consisting of 6 teeth in each group. In Group A, the cement was applied over the posts only. For the specimens in Group B, the cement was introduced into the root canals with a spiral filler and applied over the posts. In Group C, cement was injected into the root canals and then applied over the posts. Finally, for the specimens in Group D, cement was injected into the root canals and a spiral was used to spread it into the root canals, and cement was also applied over the posts. After cementation, teeth were stored in saline solution. The tensile retentive force of cast posts was evaluated using the Instron testing machine (Instron, Canton, MA).


RESULTS
The retention obtained by the 4 techniques differed significantly (p <.05). The highest tensile force to post dislodgment was observed in Group D, and the least was in Group A. Analysis of variance test revealed a highly significant difference between groups (p <.0001). According to the Fisher exact test, there was a significant increase in retention from Group A to Group D (p <.05).


CONCLUSIONS
Under the conditions of this study, the injection of cement into a root canal space followed by the use of a spiral resulted in the highest level of post retention. Retention was reduced when cement was placed using a Lentulo spiral alone (Kerr/Sybron Corp, Romulus, MI), a Jiffy tube (Teledyne Water Pik, Allegheny Teledyne Co, Fort Collins, CO) alone, or by application to the post only. J Prosthodont 2001;10:37-41.
Fakiha
Z
Z
King Saud University, College of Dentistry, Department of Restorative Dental Sciences, Riyadh 11545, Saudi Arabia. zfakiha@yahoo.com
Al-Aujan
A
A
Al-Shamrani
S
S
D000180:Acrylic Resins / Q000737:chemistry; D000704:Analysis of Variance; D002484:Cementation / Q000295:instrumentation / Q000379:methods*; D002858:Chromium Alloys / Q000737:chemistry; D016001:Confidence Intervals; D001840:Dental Bonding; D003734:Dental Casting Investment / Q000737:chemistry; D003760:Dental Impression Materials / Q000737:chemistry; D017268:Dental Prosthesis Retention; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D011176:Post and Core Technique / Q000295:instrumentation*; D018915:Root Canal Preparation / Q000295:instrumentation / Q000379:methods; D012965:Sodium Chloride; D013223:Statistics as Topic; D013499:Surface Properties; D013718:Tensile Strength; D015036:Zinc Phosphate Cement / Q000737:chemistry*
D000180:Acrylic Resins; D002858:Chromium Alloys; D003734:Dental Casting Investment; D003760:Dental Impression Materials; D012965:Sodium Chloride; D015036:Zinc Phosphate Cement