Evaluation of three different spreading forces using lateral condensa-tion technique on apical leakage and tooth fracture: an in vitro study

Abstract Background and Aim: Lateral condensation technique is one of the most frequently used techniques for root canal obturation. There were few studies in order to deter- mine the needed force for spreader penetration and its effect on apical seal. The pur- pose of this study was the in vitro evaluation of the effect of three spreader forces us- ing the lateral condensation technique and the effect of these forces on root fractures. Materials and Methods: Eighty-five human mandibular premolar single rooted teeth without severe curvature and visible fractures were chosen and randomly divided into three groups. Following canal preparation , all samples were obturated on an acrylic model using three forces (1.6, 3 and 4.5 kg) with the lateral condensation technique. The teeth were ob- served under the stereomicroscope ×6 for any fracture line and follow the clearing of the teeth the maximum dye leakage penetration was measured for each tooth. The data were analyzed by using chi-square and Kruskal-Wallis statistical tests. Results: All samples in the positive control group showed dye leakage but in the negative control group no sample showed any leakage. The mean dye penetra-tion for the first (1.6 kg), second (3kg) and third (4.5 kg) groups was 0.344 mm, 0.153 mm and 0.746 mm, respectively. The 3kg force for lateral condensation technique produced a significantly better apical seal and less leakage in comparison with the other groups (P < 0.05) and more fractures were observed with 4.5kg force (P < 0.05). Conclusion: The best force for lateral condensation in premolar teeth was 3kg and more pressure could produce more fracture. Key Words: Lateral condensation - Spreader - Leakage - Root fracture