Burklein S, Hinschitza K, Dammaschke T, Schafer E. Shaping ability and cleaning effectiveness of two single-file systems in severely curved root canals of extracted teeth: Reciproc and WaveOne versus Mtwo and ProTaper. Interna- tional Endodontic Journal. Aim To compare shaping ability and cleaning effec- tiveness of two reciprocating single-file systems with Mtwo and ProTaper rotary instruments during the preparation of curved root canals in extracted teeth. Methodology A total of 80 root canals with curva- tures ranging between 25� and 39� were divided into four groups of 20 canals. Based on radiographs taken prior to instrumentation, the groups were balanced with respect to the angle and the radius of canal curvature. Canals were prepared to the following apical sizes: Mtwo: size 35 using the single-length technique; ProTaper: F3, instruments were used in a modified crown-down manner; Reciproc and WaveOne: size 25. Using pre- and post-instrumentation radiographs, straightening of the canal curvatures was determined with a computer image analysis program. Preparation time and instrument failures were also recorded. These data were analysed statistically using anova and Student-Newman-Keuls test. The amounts of debris and smear layer were quantified on the basis of a numerical evaluation scale and were analysed statisti- cally using the Kruskal-Wallis test. Results During preparation no file fractured. All instruments maintained the original canal curvature well with no significant differences between the differ- ent files (P = 0.382). Instrumentation with Reciproc was significantly faster than with all other instruments (P 0.05), while ProTaper showed significantly more residual debris (P 0.05). Conclusions Under the conditions of this study, all instruments maintained the original canal curvature well and were safe to use. The use of Mtwo and Reciproc instruments resulted in better canal cleanli- ness in the apical part compared with ProTaper and WaveOne.

Shaping ability and cleaning effectiveness of two single-file systems in severely curved root canals of extracted teeth: Reciproc and WaveOne versus Mtwo and ProTaper.

Current challenges and concepts of the thermomechanical treatment of nickel-titanium instruments.

http://hub.hku.hk/bitstream/10722/154707/1/Content.pdf

Cyclic Fatigue and Torsional Resistance of Two New Nickel-Titanium Instruments Used in Reciprocation Motion: Reciproc Versus WaveOne

This review highlights the recent advances in X-ray microcomputed tomography (Micro-CT) applied in dental research. It summarizes Micro-CT applications in measurement of enamel thickness, root canal morphology, evaluation of root canal preparation, craniofacial skeletal structure, micro finite element modeling, dental tissue engineering, mineral density of dental hard tissues and about dental implants. Details of studies in each of these areas are highlighted along with the advantages of Micro-CT, and finally a summary of the future applications of Micro-CT in dental research is given.

/pdf/state-of-the-art-of-micro-ct-applications-in-dental-research-zay4kh5dfo.pdf

State of the art of Micro-CT applications in dental research.

Mineral trioxide aggregate (MTA) is a bioactive endodontic cement (BEC) mainly comprised of calcium and silicate elements. The cement was introduced by Torabinejad in the 1990s and has been approved by the Food and Drug Administration to be used in the United States in 1997. A number of new BECs have also been introduced to the market, including BioAggregate, Biodentine, BioRoot RCS, calcium-enriched mixture cement, Endo-CPM, Endocem, EndoSequence, EndoBinder, EndoSeal MTA, iRoot, MicroMega MTA, MTA Bio, MTA Fillapex, MTA Plus, NeoMTA Plus, OrthoMTA, Quick-Set, RetroMTA, Tech Biosealer and TheraCal LC. It has been claimed that these materials have properties similar to those of MTA without its drawbacks. In this article, the chemical composition and the application of MTA and other BECs for vital pulp therapy (VPT), including indirect pulp cap, direct pulp cap, partial pulpotomy, pulpotomy and partial pulpectomy, have been reviewed and compared. Based on selected keywords, all papers regarding chemical composition and VPT applications of BECs had been reviewed. Most of the materials had calcium and silicate in their composition. Instead of referring to the cements based on their chemical compositions, we suggest the term 'bioactive endodontic cements (BECs)', which seems more appropriate for these materials because, in spite of differences in their chemical compositions, bioactivity is a common property for all of them. Numerous articles were found regarding use of BECs as VPT agents for indirect and direct pulp capping, partial pulpotomy and cervical pulpotomy. Most of these investigations used MTA for VPT. In most studies, newly introduced materials have been compared to MTA. Some of the BECs have shown promising results; however, the number of their studies compared to investigations on MTA is limited. Most studies had several methodological shortcomings. Future investigations with rigorous methods and materials are needed.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/iej.12841

Hyeon-Cheol Kim

Papers

Cyclic Fatigue and Torsional Resistance of Two New Nickel-Titanium Instruments Used in Reciprocation Motion: Reciproc Versus WaveOne

Cyclic fatigue and fracture characteristics of ground and twisted nickel-titanium rotary files.

Potential Relationship between Design of Nickel-Titanium Rotary Instruments and Vertical Root Fracture

Shaping Ability of Reciprocating Motion in Curved Root Canals: A Comparative Study with Micro–Computed Tomography

Analysis of the Cause of Failure in Nonsurgical Endodontic Treatment by Microscopic Inspection during Endodontic Microsurgery