A Vitro Study Of Sealing Ability On High-temperature Thermoplasticized Injectable Technique For Curved Canals Of Posterior Teeth

Objectives The aim of this study was to evaluate and compare the sealability of root fillings in extracted human teeth using cold lateral condensation of gutta-percha or high-temperature thermoplasticized gutta-percha in vitro. Methods In vitro study,sixty-four freshly extracted human mature curved canals of posterior teeth were divided into four groups on the basis of root canal shape that was determined by angle of canal curve.All groups consisted of identical numbers of 16.All root canals were prepared using Nickel-titanium rotary instruments and flushed with ultrasonic irrigation.The canals of the first and second groups were obturated using cold lateral condensation and the canals of the other two groups were obturated using high-temperature thermoplasticized gutta-percha. For evaluation of the quality of the apical sealing,the canals of the first and third group were subjected to dye leakage and then cleared to allow three-dimensional assessment of dye penetration.The sealing ability of the root canals of the second and fourth group were accessed morphometrically according to the cross-sectional area at apical part(1.5mm) and middle part(3.5mm). Speed of Obturation was determined by recording the time taken to obturate canals;the extrusion of sealer and gutta-percha through the apical foramen was recorded using a simple "yes/no".At the same time,surface adaptation to the canal wall was accessed by identical morphometrical method.Results 1.The results showed that mean depths of microleakage in root canals in first group and third group was statistically significant difference.The first group was more than the third group (P＜0.05＝.2.At the 1.5mm level,the percentages of obturation of ObturaⅡ was more than that of cold lateral condensation .The difference was statistically significant(P＜0.05);At the3.5mm level, the percentages of obturation between two techniques was no statistically significant difference(P＞0.05). At apical part(1.5mm) and middle part(3.5mm),there was no statistically significant difference on obturating light curved canals and heavy curved canals (P＞0.05) with ObturaⅡ; At apical part(1.5mm) and middle part(3.5mm), there was statistically significant difference on obturating light curved canals and heavy curved canals with cold lateral condensation (P＜0.05). 3.There was statistically significant difference between ObturaⅡgroup and cold lateral condensation group on obturated time.The latter was more than the former.( P＜0.05).4.Incidence of apical sealer and gutta-percha extrusion with ObturaⅡ and cold lateral condensation was no statistically significant difference(P＞0.05). 5.At apical part(1.5mm) and middle part(3.5mm),adaptation of ObturaⅡwas higher significantly than cold lateral condensation(P＜0.05).Conclusion High-temperature thermoplasticized gutta-percha has excellent sealing ability on obturating root canal,so it is more suitable for clinical adaption than cold lateral condensation...