In Vitro Study About The Apical Sealability And Root Fracture Resistance Of Different Root Canal Sealers And Root Canal Filling Techniques

Objectives To compare of the apical sealability and fracture resistance of Zinc oxide Eugenol sealer, i Root SP sealer and AH Plus sealer and matched-taper single-cone technique, cold lateral condensation technique and warm vertical condensation technique. At the same time, The experiment also compare of the operation time of root canal filling techniques. In order to discuss the root canal sealers and root canal filling technique with perfect apical sealability and fracture resistance and provide experimental basis for choosing ideal root canal sealers and suitable root canal filling technique in the clinical treatment.Methods Experiment 1. In vitro study about apical sealability and fracture resistance of different root canal sealers: Seventy single-rooted human premo1 ars were selected and divided into 3 experimental groups(18 in each group) and a control group(n=16). The experimental groups were filled with Zinc oxide Eugenol sealer, i Root SP sealer and AH Plus sealer respectively using matched-taper single-cone technique; The control group were only filled using matched-taper single-cone technique. 1) Root apex micro-leakage experiment. 8 teeth of each group were stained by methylene blue from each group and made into transparent specimens. We measured and compared the length of root apex micro-leakage. 2) SEM experiment. The transverse-section of the other two experimental samples were observed by scanning electron microscope. 3) Fracture resistance experiment. The remaining samples of the experimental and control group were made into standard test pieces and then the test pieces were placed on the universal material testing machine. Press them until the root canal in the broken, then record and compare the pressure value. Experiment 2. In vitro study about apical sealability and fracture resistance of different root canal filling techniques: Seventy single-rooted human premo1 ars were selected and randomly divided into three experimental groups(18 in each group) and a blank control group(n=8) and a positive control group(n=8). The samples of experimental groups were filled with i Root SP root canal sealer and gutta percha after conventional root canal preparation, the filling technique are matched-taper single-cone technique, cold lateral condensation technique and warm vertical condensation technique. Record and compare the root canal filling time serious-minded. 1) Root apex micro-leakage experiment. 8 teeth of each experimental group were stained by methylene blue from each group and made into transparent specimens. We measured and compared the length of root apex microleakage. 2) SEM experiment. The transverse-section of the other two experimental samples were observed by scanning electron microscope. The samples of blank control group were dealt with root canal preparation only, the samples of positive control group without any operation. Fracture resistance experiment. 3) The remaining samples of the experimental and the two control groups were made into standard test pieces and then the test pieces were placed on the universal material testing machine. Press them until the root canal in the broken, then record and compare the pressure value. All of the measurement data of there experiments were showed as mean±SD, Using SPSS17.0 statistical package for analysis. Inspection level of α= 0.05, There are statistical significance with P<0.05.Results The experiment 1 showed that: 1) The root apex micro-leakage of three experimental groups are all shorter than the control group. The length of root apex microleakage of ZOE is longer than i Root SP sealer and AH Plus sealer(P<0.05). and the length of root apex micro-leakage between i Root SP sealer and AH Plus sealer withoutstatistical significance(P>0.05). 2) The SEM observed the gaps between root sealer and dentinal in each experimental group, the gap of ZOE is the longest and the quantity of sealer penetrate into the dentin at least, on the contrary, the gap of i Root SP sealer is the shortest and the quantity of sealer penetrate into the dentin at most. 3) The fracture resistance of the experimental groups are larger than the control group(P<0.05), The i Root SP sealer was much more improved the root fracture resistance than the other two experimental groups. but there difference were no statistically significant(P>0.05). The experiment 2 showed that: 1) The matched-taper single-cone technique takes the shortest time and the operation time of warm vertical condensation technique is less than cold lateral condensation technique, there difference are statistically significant(P<0.05). 2) The three experimental groups occurred root apex micro-leakage in different degree. But the difference were no statistically significant(P>0.05). The gaps were observed by the SEM are basically identical too. 3) The fracture resistance of the experimental groups are larger than the blank control group and there difference are statistically significant(P<0.05), The fracture resistance of matched-taper single-cone technique and positive control group are bigger than cold lateral condensation technique and warm vertical condensation technique(P<0.05). but the fracture resistance of the later two kinds of techniques were no significant difference(P>0.05).Conclusions 1 Three kinds of root canal sealers cannot filling the root canal completely, There are different degrees of root apex micro-leakage, i Root SP sealer has the best apical sealability. 2 Three king of root canal sealers all can increase the root fracture resistance, The difference about fracture resistance of there root canal sealers were no statistically significant. 3 The operation time of matched-taper single-cone technique is the shortest. on the contrary, cold lateral condensation technique takes the longest. 4 The apical sealability of three kinds of root canal filling techniques were no significant difference. 5 Three kinds of root canal filling techniques could enhance the root canal’s fracture resistance after conventional preparation, and the fracture resistance of matchedtaper single-cone technique is bigger than the other two techniques.