| Objective:Apical surgery is a common method in the treatment of endodontic surgery.Effective hemostasis,adequate preparation,and perfect filling are the key to ensure the curative effect.However,the retro-preparation and root-end filling requires sophisticated equipments and complicated operation.For those with lack of clinical experience,the accuracy is difficult to grasp and the technical sensitivity is high.In this study,the in vitro study of maxillary anterior teeth was performed by apical resection after MTA filling and MTA root-end filling after conventional root canal treatment.Micro-CT was used to evaluate the effect of the two operative methods on root canal sealing performance.To investigate the effect of apical resection after MTA filling on the apical surgery of maxillary anterior teeth,and to clarify which is the best operative methods between apicoectomy after MTA filling and MTA root-end filling after conventional root canal treatment.To provide guidance for changing the traditional operative methods of apical surgery operation of maxillary anterior teeth,in order to reduce intra-operative procedures,reduce the difficulty of surgery,reduce the requirements for instruments,and provide a theoretical basis for the convenient implementation of apical surgery.Methods:According to the inclusion and exclusion criteria,thirty-two permanent maxillary anterior teeth were extracted with the informed consent of the patient,regardless of age and sex.According to the random number table,thirty-two extracted teeth were randomly divided into two groups: group A(n=16 the group of apical resection after MTA filling)and group B(n=16 the group of MTA root-end filling after conventional root canal treatment).The extracted teeth were fixed on the operating table,pre-scanned by Micro-CT,and a continuous two-dimensional cross-sectional image was obtained.The volume,surface area and length of the root canal were calculated by using the image analysis and processing software of Micro-CT.Group A: According to the clinical operation procedure under the microscope,M3 nickel-titanium system prepared root canal to 0.04 taper 35#,1#G drilled to expand the apical foramen,create artificial apical foramen d=0.5mm,MTA filled root canal to distance at the apical stop of 7.0±0.1mm,the hot gutta-percha was backfilled the upper part of the root canal,and the apical 3 mm of each sample was resected perpendicular to the long axis of the tooth.Group B: According to the clinical operation procedure under the microscope,M3 nickel-titanium system prepared root canal to 0.04 taper 35#,1#G drilled to expand the apical foramen,create artificial apical foramen d=0.5mm,the root canal was filled with hot gutta-percha,and the apical 3 mm of each sample was resected perpendicular to the long axis of the tooth,and the root end was prepared to a depth of 3 mm using ultrasonic tip powered by the DTE ultrasonic instrument.All the experimental teeth in groups A and B were scanned under Micro-CT,the percentage volume range of void the gutta-percha and MTA and total filling materials,the percentage volumes of the gutta-percha and MTA and total filling materials were calculated.The data were collated,and the statistical description and statistical analysis were performed by Excel and SPSS22.0.The quality of apical resection after MTA filling and MTA root-end filling after conventional root canal treatment was evaluated.The Differences in root canal sealing performance between apical resection after MTA filling and MTA root-end filling after conventional root canal treatment were compared.Results:1.Thirty-two extracted human maxillary anterior teeth were used for this study and were randomly divided into two groups: group A(n=16 the group of apical resection after MTA filling)and group B(n=16 the group of MTA root-end filling after conventional root canal treatment).Before treatment,the volume,surface area and length of the AB group were compared,which satisfied the normality and homogeneity of the variance.The t-test showed no statistical difference(P>0.05).2.Micro-CT scan samples,quantitative analysis of the voids and gaps generated by the filling materials of the two groups A and B by the ?-CT V6.1 image analysis software,and compare the filling effects of the two groups.The data satisfies the test of normality and homogeneity of variance.The results showed that the percentage volume range of total void and the percentage volume range of void of the gutta-percha were significantly higher in group B than in group A,and the difference was statistically significant(P < 0.05).The percentage volumes of total filling materials and percentage volumes of filling materials of the gutta-percha in the group A was higher than that in group B,which was statistically different(P < 0.05).There was no statistical difference in the percentage volume range of void of the MTA and the percentage volumes of MTA filling materials between the two groups(P>0.05).3.The volumes of total filling materials plus volume range of total void,operative method and total surface area were analyzed as independent variables.The results showed that the operative method had a statistically significant effect on the percentage volume range of total void(P < 0.05),suggesting that the percentage volume range of total void of group B was higher than that of group A.The volumes of gutta-percha plus volume range of void of the gutta-percha,operative method and surface area of the gutta-percha were analyzed as independent variables.The results showed that the operative method had a statistically significant effect on the percentage volume range void of the gutta-percha(P < 0.05),suggesting that the percentage volume range void of the gutta-percha of group B was higher than that of group A.The volumes of MTA plus volume range of void of MTA,operative method and surface area of MTA were analyzed as independent variables.The results showed that the influence of independent variables on the percentage volume range void of MTA had no statistical significance(P>0.05).Conclusion:The results of this study showed that the apical resection after MTA filling can achieve the same apical sealing effect as MTA root-end filling after conventional root canal treatment,suggesting that apical resection after MTA filling has clinical application value.Especially for those who have the limitations of anatomical structure,instruments/ equipment,difficult in hemostasis,and the effect of surgical approach will increase the difficulty of apical surgery,apical resection after MTA filling is an efficient and effective method.At the same time,the results of this experiment showed that there were voids and gaps in the two operative method of apical resection after MTA filling and MTA root-end filling after conventional root canal treatment..It also suggested that further research on materials,techniques and methods is needed to improve the success rate of apical surgery in the future. |
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