Research On Vertical Compaction Technique

Part1 Root Canal Morphology of Single-mesial-rooted of the Mandibular First Molar and Effect of the Different Tapered Canals in Mandibular First Molar on Apical Sealing Ability of Vertical Compaction TechniqueExperiment 1 Root Canal Morphology of Single-mesial-rooted of theMandibular First MolarObjective: To evaluate root canal morphology of single-mesial-rooted of the mandibular first molar.Material and Methods: 100 single-mesial-rooted of the mandibular first molars were selected. The roots were injected with India ink, demineralized with nitric, dehydrated with ethanol, cleared with methylsalicylate and evaluated under magnification( X 3).Results: There were 9 cases in type I ,31 cases in type II,1 case in type III,49 cases in typeIV,2 cases in typeV,6 cases in type VI,no case in type Vfl and type VI according Vertucci classification . There was one case in type 2-3 and another case in type 1-3-1. The incidence of lateral canal was 41%, in which there were 9.75% in coronal third, 21.95% in middle third and 68.30% in apical third. The incidence of isthmus was 58%, in which there were 13.79% in coronal third, 75.86% in middle third, 10.34% in apical third.Conclusion: The single mesial-rooted of the mandibular first molar usually had two canals. There were high incidence of lateral canals and isthmus. The lateral canals were concentrated on apical third, while the isthmuses were more concentrated on middle third of root canal.Experiment 2 Comparison of Apical Sealing Ability of VerticalCompaction Technique in Different Tapered Canals - Taper 0.06 andTaper 0.10 in Mandibular First MolarObjective: The study sought to investigate apical sealing ability of vertical compaction in different tapered canals-taper 0.06 and taper 0.10 in mandibular first molar.Material and Methods: 30 extracted, single-mesial-rooted with type IV root canals according to Vertucci classification were used. Both canals of each mesial root were instrumented to size 30 with different taper-taper 0.06 and taper 0.10. Then all of canals were obturated with vertical compaction technique. Dye penetration and clearing method were used to assess the apical sealing ability.Results: The mean microleakage of taper 0.06 canals was 1.20+0.70mm. The mean microleakage of taper 0.10 canals was 0.43+0.29mm. 8 cases of overfilling were found in taper 0.06 canals, while 1 case in taper 0.10 canals.Conclusion: Taper 0.10 was better choice when vertical compaction technique was used in mandibular first molar.