Basic Research|Articles in Press

New Ultrasonic Tip for Root Canal Filling of the Mesial Canals of Mandibular Molars with Isthmus: A Laboratory Evaluation Using Computed Microtomography

Published:February 23, 2023DOI:



      The obturation quality of the mandibular molar mesial canals and isthmuses with two thermoplastic techniques, ultrasonic vertical condensation (UVC) and continuous wave of condensation (CWC), was evaluated using computed microtomography (μCT).


      Thirty-six human mandibular molars had been previously scanned and analyzed using μCT for mesial roots with morphologically similar isthmuses for this study. Coronal access and confirmation of foraminal patency were performed, and the actual length of the teeth was established using a clinical microscope (40X magnification). The canals were prepared using ProTaper Gold instruments up to #F3, with 2.5% sodium hypochlorite as the irrigant solution, followed by a passive ultrasonic irrigation protocol. The specimens were randomly divided into the UVC and CWC groups based on the obturation technique to be used. Obturation was performed with #F3 gutta-percha cones cemented using AH Plus Jet sealer. The μCT scans were performed after 15 days, and the images were evaluated by a calibrated examiner blinded to the experimental groups to determine the filling rate of the entire canal area, including the main canal and isthmus. Student's t-test was used for statistical analysis; P values ≤0.05 were considered significant.


      Neither of the thermoplastic obturation techniques achieved complete filling of the canals (86.3% for UVC and 91.4% for CWC), with a statistically significant difference between them (P = .029).


      Under the conditions of the study, it can be concluded that none of the techniques completely filled the canal/isthmus of the mandibular molars; however, the CWC exhibited better performance.

      Key Words

      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Journal of Endodontics
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Zhang P.
        • Yuan K.
        • Jin Q.
        • et al.
        Presence of voids after three obturation techniques in band-shaped isthmuses: a micro-computed tomography study.
        BMC Oral Health. 2021; 21: 227-235
        • Ricucci D.
        • Siqueira Jr., J.F.
        Biofilms and apical periodontitis: study of prevalence and association with clinical and histopathologic findings.
        J Endod. 2010; 36: 1277-1288
        • Fan B.
        • Pan Y.
        • Gao Y.
        • et al.
        Three-dimensional morphologic analysis of isthmuses in the mesial roots of mandibular molars.
        J Endod. 2010; 36: 1866-1869
        • Libonati A.
        • Montemurro E.
        • Nardi R.
        • Campanella V.
        Percentage of gutta-percha–filled areas in canals obturated by 3 different techniques with and without the use of endodontic sealer.
        J Endod. 2018; 44: 506-509
        • Keleş A.
        • Alcin H.
        • Kamalak A.
        • Versiani M.A.
        Micro-CT evaluation of root filling quality in oval-shaped canals.
        Int Endod J. 2014; 47: 1177-1184
        • Schäfer E.
        • Nelius B.
        • Bürklein S.
        A comparative evaluation of gutta-percha filled areas in curved root canals obturated with different techniques.
        Clin Oral Investig. 2012; 16: 225-230
        • Jain H.
        • Ballal N.V.
        Comparison between the use of thermoplasticized gutta-percha and a polydimethyl siloxane-based material in filling internal resorptive cavities using spiral computed tomography.
        Microsc Res Tech. 2019; 82: 149-152
        • Valdivia C.J.E.
        • Machado M.E.L.
        Onda ultrassônica de termoplastificação da obturação pela técnica segmentada TT–ultrasonic wave of obturation by segmented technique.
        Full Dent Sci. 2018; 9: 135-143
        • Cho Y.S.
        Ultrasonic vibration and thermo-hydrodynamic technique for filling root canals: technical overview and a case series.
        Int Endod J. 2021; 54: 1668-1676
        • Baumgardner K.R.
        • Krell K.V.
        Ultrasonic condensation of gutta-percha: an in vitro dye penetration and scanning electron microscopic study.
        J Endod. 1990; 16: 253-259
        • Bailey G.C.
        • Ng Y.L.
        • Cunnington S.A.
        • et al.
        Root canal obturation by ultrasonic condensation of gutta-percha. Part II: an in vitro investigation of the quality of obturation.
        Int Endod J. 2004; 37: 694-698
        • Alcalde M.P.
        • Bramante C.M.
        • Vivan R.R.
        • et al.
        Intradentinal antimicrobial action and filling quality promoted by ultrasonic agitation of epoxy resin-based sealer in endodontic obturation.
        J Appl Oral Sci. 2017; 25: 641-649
        • Iglecias E.F.
        • Freire L.G.
        • Candeiro M.
        • et al.
        Presence of voids after continuous wave of condensation and single-cone obturation in mandibular molars: a micro-computed tomography analysis.
        J Endod. 2017; 43: 638-642
        • Vertucci F.J.
        Root canal anatomy of the human permanent teeth. Oral Surgery.
        Oral Med Oral Pathol. 1984; 58: 589-599
        • Gillen B.M.
        • Looney S.W.
        • Gu L.S.
        • et al.
        Impact of the quality of coronal restoration versus the quality of root canal fillings on success of root canal treatment: a systematic review and meta-analysis.
        J Endod. 2011; 37: 895-902
        • Endal U.
        • Shen Y.
        • Knut A.
        • et al.
        A high-resolution computed tomographic study of changes in root canal isthmus area by instrumentation and root filling.
        J Endod. 2011; 37: 223-227
        • Silva L.
        • Nejaim Y.
        • Jo E.
        • et al.
        Evaluation of root canal configuration of mandibular molars in a Brazilian population by using cone-beam computed tomography: an in vivo study.
        J Endod. 2013; 39: 849-852
        • Siqueira J.F.
        • Alves F.R.F.
        • Versiani M.A.
        • et al.
        Correlative bacteriologic and micro-computed tomographic analysis of mandibular molar mesial canals prepared by self-adjusting file, reciproc, and twisted file systems.
        J Endod. 2013; 39: 1044-1050
        • Tahmasbi M.
        • Jalali P.
        • Nair M.K.
        • et al.
        Prevalence of middle mesial canals and isthmi in the mesial root of mandibular molars: an in vivo cone-beam computed tomographic study.
        J Endod. 2017; 43: 1080-1083
        • Cavenago B.C.
        • Del Carpio-Perochena A.E.
        • Amoroso-Silva P.A.
        • et al.
        Evaluation of mesial root canals of mandibular molars obturated with gutta-percha and resilon techniques.
        Eur Endod J. 2017; 2: 1-7
        • Wolf T.G.
        • Paqué F.
        • Patyna M.S.
        • et al.
        Three-dimensional analysis of the physiological foramen geometry of maxillary and mandibular molars by means of micro-CT.
        Int J Oral Sci. 2017; 9: 151-157
        • Keleş A.
        • Keskin C.
        A micro-computed tomographic study of band-shaped root canal isthmuses, having their floor in the apical third of mesial roots of mandibular first molars.
        Int Endod J. 2018; 51: 240-246
        • Keles A.
        Presence of voids after warm vertical compaction and single-cone obturation in band-shaped isthmuses using micro-computed tomography: a phantom study.
        Microsc Res Tech. 2020; 83: 370-374
        • Bhandi S.
        • Shyakhy M.
        • Abumelha A.S.
        • et al.
        Complete obturation—cold lateral condensation vs thermoplastic techniques: a systematic review of micro-CT studies.
        Materials (Basel). 2021; 14: 115
        • Baser E.D.
        • Keles A.
        • Aslan B.
        Micro-CT evaluation of the quality of root fillings when using three root filling systems.
        Int Endod J. 2017; 50: 499-505
        • Kalantar M.M.R.
        • Mortaheb A.
        • Zare J.M.
        • Gilbert B.E.
        Micro-CT evaluation of four root canal obturation techniques.
        Scanning. 2021; 2021: 6632822
        • Kim J.A.
        • Hwang Y.C.
        • Rosa V.
        • et al.
        Root canal filling quality of a premixed calcium silicate endodontic sealer applied using gutta-percha cone-mediated ultrasonic activation.
        J Endod. 2018; 44: 133-138
        • Cho Y.S.
        • Kwak Y.
        • Shin S.J.
        Comparison of root filling quality of two types of single cone-based canal filling methods in complex root canal anatomies: the ultrasonic vibration and thermo-hydrodynamic obturation versus single-cone technique.
        Materials (Basel). 2021; 14: 1-10
        • Şımşek N.
        • Keleş A.
        • Ahmetoğlu F.
        • et al.
        3D micro-CT analysis of void and gap formation in curved root canals.
        Eur Endod J. 2017; 2: 1-5
        • Celikten B.
        • Jacobs R.
        • Vasconcelos K.F.
        • et al.
        Assessment of volumetric distortion artifact in filled root canals using different cone-beam computed tomographic devices.
        J Endod. 2017; 43: 1517-1521