Efficacy of continuous rotation Vs reciprocation motion in the removal of Bio-ceramic based root canal filling obturated with two different techniques : (An in vitro study) /

Abstract

The aim of the study was to assess and compare the efficacy of continuous rotation versus reciprocation motion in the removal of bio ceramic root canal filling material obturated with two different techniques (Single cone and Lateral compaction) in terms of the amount of residual filling material, changes in remaining mesial and distal dentine thicknesses and time required for filling material removal. Fifty-six mandibular premolars with single canal were selected in this study to assess the amount of residual filling material (bio-ceramic sealer gutta-percha) using stereomicroscope, Measure remaining mesial and distal dentin thicknesses following removal of root canal filling material using continuous and reciprocative motion using CBCT and Calculate time required for removal of root canal filling material using continuous and reciprocative systems using stopwatch. Samples were classified into two main groups according to the obturation technique used. Group I: Root canal obturated with single cone technique (n=28). Group II: Root canal obturated with lateral compaction technique (n=28). And further subdivided into two sub-divisions according to kinematic file system used. Subgroup (IA): Root canal filling material was removed using continuous rotation motion Pro-taper Next file system (n=14). Subgroup (IB): Root canal filling material was removed using reciprocation motion Reciproc file system (n=14). Subgroup (IIA): Root canal filling material was removed using continuous rotation motion Pro-taper Next file system (n=14). Subgroup (IIB): Root canal filling material was removed using reciprocation motion Reciproc file system (n=14). Mesial and Distal dentine thicknesses were measured using CBCT before obturation and after filling material removal. Measurements of dentinal thickness were evaluated from the axial view. Dentin thickness was measured from mesial and distal sides of the canal space. Measurements were taken at three standard points; 3, 6, 9 mm from the apex. For each sample in each subgroup an average was calculated for both mesial and distal dentin thicknesses to evaluate the percent of change before obturation and after re treatment. Fusion of the primary image (before obturation) to the secondary image (after filling material removal) was then carried out by first using manual registration through different points along the root of the samples. Superimposition was completed automatically using software allowing the best possible accuracy. For identification, each image—primary and secondary—was assigned a colour code. The original image was used to capture the initial measurements. Next, the primary imagine was cancelled, leaving the secondary image, and the measurement on the primary image was left in place. To ensure standardisation, a fresh measurement was taken on the secondary picture in the same plane direction and cut as the first image. Each tooth was decoronated using a disc in a low-speed micromotor after the root canal filling was removed and CBCT images were captured. Canal orifices were sealed off with damp cotton pellets. Each root sample was grooved longitudinally at the mesial and distal surfaces using linear precision saw and was divided mesiodistally into buccal and lingual halves using a chisel and mallet. The two halves were examined under the stereomicroscope to determine which half was the most representative of the two. The selected half was marked into coronal, middle, apical thirds and inspected under stereomicroscope at magnification 20X. Images were captured using a digital camera fitted on the microscope, then images were transferred to desktop and saved as JPEG format. Image analysis with Image J software was used to calculate the percentage area of the residual filling material within each third separately. The mean percentage value for each third and for the whole canal length was calculated. Time required for removal of bio-ceramic root canal filling material by each file system was determined using a stopwatch. Results revealed: 1.CBCT results showed that removal of bio-ceramic root canal filling material procedure resulted a significantly change in the thicknesses of the remaining mesial and distal dentin walls as the single cone technique showed statistically significantly lower percentage change in dentin thickness than lateral compaction technique. 2- Stereomicroscopic results revealed that there was a significant decrease in percent remnants on using reciprocation motion with single cone technique. Both kinematics failed to remove all residual bio-ceramic root canal filling material completely. 3.Time required in removal of bio-ceramic root canal filling material was significantly less by using reciprocative motion than continuous rotation motion.