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Dental Tribune Middle East & Africa Edition | July-August 2015 11endo Tribune Adaptation in Motion Confidence in your hands < Page 10 nal preparation by not reaching the working length, one possible solution is to increase coronal flaring by brushing with the last instrument. By doing so a TF/ TFA instrument will increase the dimensions of the prepared canal in the coronal part, solv- ing the problem related of “GP Taper-lock”. Correct apical fitting. Clinicians may experience two different clinical problems in the api- cal fitting: the need for a better apical tug-back, which may re- quire slightly cutting the tip of the master cone, and the fitting related to the amount of canal transportation. Thefirstcasemayhappendueto the different dimensions; toler- ance of a GP cone may be slight- ly smaller than the nominal size, increasing the risk of overfilling during obturation. In such cases, the advice is to slightly increase the dimensions of the master cone by cutting 0.5/1 mm off the tip, or ideally to precisely re- calibrate the master cone using a tip-snip device. This can also happen if a canal is iatrogeni- cally slightly over-instrumented (due to a mistake in the working length determination or in the position of the rubber stop on the file); the apical constriction is now modified and the cone fitting must try to accommodate this mistake by increasing the tip size of GP master cone. TF/TFA are significantly more flexible than the majority of competitor NiTi rotary instru- ments. As a consequence they tend to follow more precisely and maintain the original tra- jectory of root canals, minimis- ing canal transportation. Canal transportation is a mistake that frequently occurs when a rigid file is inserted into a curvature, and tends to straighten it by cut- ting more in the inner part of the curvature coronally and in the outer part apically. However, this mistake, which can affect quality of debridement, makes insertion of master GP cone easier, espe- cially when complex, double or triple curvatures are present. This is why the TF/TFA user may clinically experiment with a slightly more difficult inser- tion of the master GP cone to the working length. If this problem occurs, once again slightly in- creasing circumferential filing can help. Conclusions Hence we may conclude that TF/TFA users should preferably use TF/TFA cones that perfectly match the prepared canals. By doing so, fitting the master GP cone becomes much easier and morepredictable,andinthevery few cases where some problems can still be found, the provided clinical tips may help clinicians in understanding problems and finding proper solutions. References 1. Briseño Marroquín B, Wolter D, Willershausen-Zönnchen B. Dimensional variability of non-standardized greater taper finger spreaders with matching gutta-percha points. Int Endod J. 2001 Jan;34(1):23-8. 2. Chesler MB, Tordik PA, Ima- mura GM, Goodell GG. Intra manufacturer diameter and ta- per variability of rotary instru- ments and their corresponding Gutta-percha cones. J Endod. 2013 Apr;39(4):538-41. 3. Hatch GW, Roberts S, Joyce AP, Runner R, McPherson JC 3rd. Comparative study of the variability of 0.06 tapered ro- tary endodontic files to current taper standards. J Endod. 2008 Apr;34(4):463-5. 4. Gambarini G. Glassman G. TF Adaptive: a novel approach to root canal instrumentation. Oral Health. May 2013: 22-30 Fig. 1 Fig. 2 Fig. 3 Prof. Gianluca Gambarini, M.D., D.D.S., Italy Is full-time Professor of End- odontics at Sapienza University of Rome and Head of the End- odontic Department, as well as a researcher and international lecturer. Prof. Gambarini has a particular interest in clinical endodontics and related materials. He is a consultant for a number of man- ufacturers, helping to develop new technologies, operative pro- cedures and materials for root canal treatment. Prof. Gambarini maintains a private practice limited to end- odontics in Rome, Italy. About the Author