Evolving Trends in Endodontic Research: An Assessment of Published Articles in 2 Leading Endodontic Journals.

INTRODUCTION: The aim of this study was to evaluate and analyze the evolving trends in endodontic research in 2 leading endodontic journals (ie, Journal of Endodontics and International Endodontic Journal) in articles published from January 2009 to December 2013. The differences in content between this period and a 10-year earlier period from January 1999 to December 2003 were also evaluated. METHODS: Each journal's content was accessed through the web edition. For each article, the following parameters were recorded: number of authors, article type, number of affiliations, field of study, source of article, and geographic origin. The recorded data were analyzed using both descriptive and analytic statistics. RESULTS: During 2009-2013 (second period), the mean number of authors per article increased significantly compared with 1999-2003 (first period). The main volume of the literature in both periods and journals was original research articles. The number of published reviews increased significantly from the first to the second study period in contrast to case reports/clinical articles, which presented a significant decrease. "Endodontic materials" was the most prevalent thematic category in both study periods. The number of published articles related to "biology" and "chemical preparation and disinfection" increased significantly from the first to the second study period. On the contrary, the number of articles regarding "obturation and microleakage" presented a considerable decrease at the same time. The United States was the leading country in the number of publications in the first period followed by Brazil. In the second period, this rank was reversed with Brazil becoming the leading country followed by the United States. CONCLUSIONS: In the last 15 years, the progress of the specialty of endodontology was apparent as shown through the trends and shifts in research orientation in published articles in the 2 leading endodontic journals. The results of the present reviewing process encourage both journals to publish well-designed research projects with a high degree of difficulty, thus contributing to a more evidence-based approach of endodontology.

A comparative study of the effects of two nickel-titanium preparation techniques on root canal geometry assessed by microcomputed tomography.

The present study was conducted with the aim of evaluating and comparing the effects of a new Hero group (Endoflare, Hero-shaper, and Hero-apical; Micro-Mega, Besancon, France) and Protaper Ni-Ti rotary instruments (Dentsply/Maillefer, Ballaigues, Switzerland) on root canal geometry in extracted human teeth using microcomputed tomography (muCT). Twenty-two mesial root canals of mandibular first molars were randomly divided into two groups. Canals were scanned before and after preparation with both systems. Cross-sectional images of each canal were obtained at 2-mm intervals. Differences in canal roundness, cross-sectional area, perimeter of each canal before and after instrumentation, and the extent of root canal transportation were calculated using image analysis software. There was no difference between the two rotary systems in regards to working time. Both systems create a similar round shape after instrumentation regardless of the initial root canal's shape. The Hero instruments showed a greater cutting efficiency compared with the ProTaper at the levels of 8 mm, 6 mm, and 4 mm but not at the level of 2 mm. On the other hand, the ProTaper seems to have a similar cutting efficiency at all levels. However, the ProTaper showed a tendency toward apical transportation. Under the conditions of the present study, both preparation techniques prepared the canals rapidly with a sufficient round shape. Despite that, it seems that there is a great potential for the improvement of shaping ability of rotary instruments. Hybrid instrumentation techniques should be evaluated by future studies in order to provide better results regarding the shaping ability of rotary instruments.

A l2-month longitudinal in vitro leakage study on a new silicon-based root canal filling material (Gutta-Flow).

OBJECTIVE: This study was performed to determine in vitro the short- and long-term sealing ability of a recently developed silicon-based root canal filling material (Gutta-Flow). STUDY DESIGN: Sixty human upper central incisors were divided into 3 groups (n = 20). The root canals were instrumented and obturated with laterally compacted gutta-percha and AH26 sealer (group 1), continuous-wave thermal compaction (System B technique) and AH26 sealer (group 2), and Gutta-Flow technique (group 3). Leakage along entire root canal fillings was measured by the movement of an air bubble in a micropipette connected to the experimental root using a fluid-transport model. Short-term leakage measurements were carried out for 3 hours after 24 hours of equilibrium establishment. Leakage was measured again and at 3, 6, and 12 months after the initial measurement. RESULTS: At the 3-hour measurement, no significant differences were found among the 3 experimental groups. Long-term leakage measurements showed that at 3 and 6 months no significant differences were existed between Gutta-Flow and the other 2 techniques. However, at 12 months, root canal fillings with Gutta-Flow leaked significantly less than fillings of lateral compaction and System B technique. CONCLUSIONS: Gutta-Flow technique showed a similar sealing ability to either lateral compaction or System B technique. This comparison improved significantly over time. These findings may be related to the possible expanding capacity of the material and the partial dissolution of the sealer over time in the other 2 groups.

A comparative study of contact angles of four different root canal sealers.

The present in vitro study was conducted with the aim of evaluating and comparing the contact angles of three different types of root canal sealers--Roth 801, AH26, and RSA RoekoSeal--with the contact angle of a newly developed silicone-based root canal filling material (Gutta-Flow) on dentin and gutta-percha surfaces at two different time periods. The contact angles were determined mathematically by measuring software and were calculated from base width and height of the droplet meniscus of each sealer. Under the conditions of this study, Roth 801 and AH26 recorded lower values of contact angles when root dentin surface was used as the substrate. RSA RoekoSeal and Gutta-Flow seem to spread similarly on dentin and gutta-percha surfaces, although the contact angles of these silicone-based sealers were found to be significantly higher than the contact angles of Roth 801 and AH26 sealers. According to these findings, it can be concluded that conventional root canal sealers (Roth 801 and AH26) may passively have the potential for better wettability of dentin and gutta-percha surfaces than that of silicone-based sealers (RSA RoekoSeal and Gutta-Flow). This fact means that Roth 801 and AH26 may have a better spreading capacity under clinical conditions on the root canal walls and gutta-percha surfaces. Application of a sufficient load during lateral or vertical compaction seems to be needed for RSA RoekoSeal and Gutta-Flow to satisfactorily wet gutta-percha and dentin under clinical conditions.