A research project supported by the University of Iowa College of Dentistry and Dental Clinics' Clinical/Dental Education Research Initiative Support Program (CRISP) has generated new findings that could help clinicians improve root canal treatment outcomes while advancing understanding of emerging endodontic materials and techniques.
Led by Anelise Viapiana Masiero, associate professor in the Department of Endodontics, the project examined how instrumentation approaches, irrigation techniques, and heat application influence the performance of contemporary calcium silicate-based endodontic sealers. Conducted through a collaboration between the University of Iowa and the University of São Paulo, the research also served as part of the doctoral training of Iandara de Lima Scardini.
The CRISP-funded project focused on two critical aspects of root canal therapy. The first investigated how different irrigation protocols affect smear layer removal and sealer penetration into dentinal tubules following minimally invasive and conventional instrumentation techniques. Minimally invasive instrumentation is designed to preserve more tooth structure, but smaller canal preparations may also create challenges for effective irrigation and cleaning. Understanding how different irrigation technologies perform under these conditions may therefore help inform the development and selection of treatment strategies.
The second examined how heat alters the physicochemical properties of modern calcium silicate-based sealers used during warm obturation procedures.
In the irrigation study, researchers evaluated 100 extracted human teeth using scanning electron microscopy and confocal laser scanning microscopy. The team compared three irrigation approaches: ultrasonic activation, laser-activated irrigation, and the GentleWave® System. Although all three protocols achieved similar levels of smear layer removal, GentleWave® and laser-activated irrigation resulted in superior sealer penetration in the apical third of minimally invasive preparations compared with ultrasonic activation. Researchers also observed dentin erosion in specimens from the ultrasonic and laser-activated irrigation groups, while no erosion was identified in specimens treated with GentleWave®.
These findings provide new insight into how irrigation technologies interact with modern instrumentation strategies particularly when more conservative canal preparations are used. Rather than establishing the superiority of a single irrigation approach, the results highlight potential benefits and trade-offs associated with different technologies and provide additional evidence that may help inform future research and clinical decision-making.. A manuscript describing these results, authored by Iandara de Lima Scardini, Anelise Viapiana Masiero, Abhishek Parolia, Fabricio Teixeira, and collaborators, is currently under review at the Journal of Endodontics.
The second study evaluated three contemporary calcium silicate-based sealers: BC Sealer Ion+, EndoSequence BC Sealer HiFlow, and NeoSEALER EZFlo. Researchers assessed properties including flow, setting time, solubility, calcium release, pH, dimensional stability, and chemical composition before and after heat exposure. The results showed that heat affected some characteristics, particularly flow and setting time, while maintaining other important biological and physicochemical properties. These findings offer valuable information for clinicians who use warm obturation techniques and contribute to a better understanding of how newer sealers perform under clinically relevant thermal conditions.
The heat-related study was published in the Journal of Endodontics in 2025, representing a significant scholarly outcome of the project.
Beyond its scientific contributions, the project generated important educational and professional opportunities. The research directly supported two completed chapters of Iandara de Lima Scardini's doctoral dissertation at the University of São Paulo. Following completion of the degree, Scardini successfully competed for faculty appointments in Brazil and now serves as a faculty member in the Department of Endodontics at the University of São Paulo.
The project also expanded the international research collaboration between the University of Iowa and the University of São Paulo and provided opportunities for dissemination at major scientific meetings. Findings were presented internationally at the 2025 Annual Meeting of the American Association of Endodontists, where two abstracts highlighted the irrigation and sealer studies. Research results also were presented at the XXVII Research Meeting of the University of São Paulo School of Dentistry. In addition, the irrigation study received first-place honors in the doctoral research category for basic sciences at the institution's annual research meeting.
According to Anelise Viapiana Masiero, the project achieved all of its original objectives and exceeded expectations for scientific productivity, dissemination and research training. By supporting the investigation of emerging endodontic materials and technologies, the CRISP-funded work has strengthened international collaboration, contributed to the development of a new researcher and faculty member, and generated evidence that adds to the scientific foundation supporting contemporary endodontic practice.