Effect of Different Techniques of Immediate and Delayed Post Space Preparation on Apical Seal

Raghad Al-Askary,Sabah Ismail,Nawal Al-Sabawi

doi:10.33899/rden.2012.65073

Abstract

The purpose of this study was to investigate the effect of different post space preparation techniques and times on the apical seal of two types of gutta-percha obturation techniques. Materials and methods: Two hundred extracted human lower premolars were selected for this study. All teeth were decoronated to adjust the working length at 14 mm. The canals were instrumented with ProTaper rotary instruments to size F3. The (200) root canals were randomly divided into two groups (100) of each according to the obturating method. Then each group was sub divided into (10) sub groups (10) of each (2 control groups and 8 experimental groups). Nine mm segment of gutta-percha was removed from the roots in each of the experimental groups either immediately after obturation or 7 days later using either heated pluggers, or Gates-Glidden drills or ProTaper rotary instruments or peeso reamers. The roots in the control groups were left without any post space preparation. The canal orifice of the roots in the experimental groups was sealed with amalgam. The extend of linear dye leakage was measured in mm with a stereomicroscope at (X 20). One-way ANOVA and sheffe statistical analysis were performed to the data collected. Results: The groups with ProTaper rotary instrument prepared the post space immediately after obturation( gps 3,11), showed the lowest mean leakage, but the difference was not statistically significant than the other experimental groups. T-test represented no significant differences existed at either two time interval studied and the type of obturation techniques. Sheffe-test for the post space preparation techniques revealed that there were a significant differences occurred with the use of ProTaper rotary instruments regardless the time interval and the obturation techniques. Conclusions: ProTaper rotary instrument provided less microleakage comparing to the other instruments used to prepare the post space. The post space preparation did not affect the apical seal in comparison with that of the intact filling.

Highlights

Treated teeth often lack sufficient support for a permanent restoration
Several factors can affect the integrity of the apical seal while post space is prepared such as length of remaining gutta-percha, time of removal of the filling material and method of gutta-percha removal.(1,5,6) Few studies have investigated the effect of post space preparation on the integrity of the apical seal of the teeth obturated initially by different material and obturation technique.(1,4) There is no consensus on the time interval between the endodontic treatment and the post preparation with some authors proposing an immediate preparation and others recommending different time intervals.(7,8) The procedures of preparing the post space are critical, and care is required to maintain the root canal seal and the aseptic conditions achieved with endodontics.(5,6,8)
Sheffe-test for comparing the four method of post space preparation (Table 7) revealed that the least leakage was detected for groups with ProTaper (NiTi) rotary system regarding the type of obturation technique and the time interval for the post space preparation

Summary

Introduction

Treated teeth often lack sufficient support for a permanent restoration. An additional retention can be necessary gained from the root canal These teeth often may require the use of an intra-canal post for retention of the core and to disperse the forces along the root. In order to create space for a post, part of the root canal filling material must be removed.(1,2,3) Many techniques are used to remove gutta-percha, chemical using a solvent such as chloroform, thermal using hot endodontic pluggers, and mechanical, using a rotary instrument such as a Gates Glidden or a peeso reamer (2). A nickel titanium (NiTi) drill with a non cutting tip and non cutting lateral surface has been proposed for removing gutta-percha and preparing the post space without enlarging the canal diameter like the other drills that might remove an excessive amount of root canal dentin and reducing the strength of the root.(4) During preparation of the post space the residual filling material may be dislodged, twisted or vibrated which creates a pathway for bacterial invasion and reinfection of the root canal system. Several factors can affect the integrity of the apical seal while post space is prepared such as length of remaining gutta-percha, time of removal of the filling material and method of gutta-percha removal.(1,5,6) Few studies have investigated the effect of post space preparation on the integrity of the apical seal of the teeth obturated initially by different material and obturation technique.(1,4) There is no consensus on the time interval between the endodontic treatment and the post preparation with some authors proposing an immediate preparation and others recommending different time intervals.(7,8) The procedures of preparing the post space are critical, and care is required to maintain the root canal seal and the aseptic conditions achieved with endodontics.(5,6,8)

Methods

Results

Discussion

Conclusion