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10 Dental Tribune Middle East & Africa Edition | July-August 2015mCME < Page 9 monitoring for potential condi- tions associated with medica- tions being used to treat sleep disorders. Appendix Patients answering yes to any of the following questions may need to be referred to a sleep physician. • Do you snore? • Have you ever been diagnosed with high blood pressure? • Has there been any witnessed stopping of breathing or gasping for breath during sleep? • Do you know your neck size? If so, is it more than 17 inches for men or 15 inches for women? • Have you ever been told to use a CPAP or breathing machine while sleeping? • Do you and your partner sleep in separate rooms because of your loud snoring? • Do you doze off unintention- ally during the day? • Do you often wake up feeling tired or having a headache? • Do you have problems concen- trating for long periods of time? References 1. Pagel, JF, (2012, July 8), The burden of obstructive sleep ap- nea and associated excessive sleepiness; The Journal of Fam- ily Practice, (1–6). Retrieved July 8, 2012 from www.findarticles. com/p/articles/mi_m0689/ is_8_57/ai_n28023915/. 2. Clinical Staff (2012) Mayo Foundation for Medical Educa- tion and Research (MFMER). 2012, June 29, Mayo Clinic. Definition of Sleep Apnea. Re- trieved July 1, 2012 from www. mayoclinic.com/health/sleep- apnea/DS00148. 3.Prinsell,JR,(2002,November), Maxillomandibular Advance- ment Surgery for Obstructive Sleep Apnea Syndrome; Journal of the American Dental Asso- ciation, Vol. 133, pp. 1489–1496 [PubMed]. Editorial note: The full list of references is avail- able from the publisher. Nancy Costa-Larson, RDH, BS, MHA, has worked in the dental field for 20-plus years as well as in the medical community for three years. She works as an active clinician and assistant clinical direc- tor in a non-profit clinic in Bir- mingham, Ala., working with students from the University Of About the Author Matching Gutta-percha cones with TF/TF Adaptive Instruments By Prof. Gianluca Gambarini, Italy I ntroduction With the widespread use of the rotary NiTi instruments, matchedtaper gutta-percha (GP) cones (of greater tapers) were developedtomakerootcanalob- turation techniques easier, more predictable and improve quality. Nowadays many manufacturers commercialise matched-taper GP cones meant to be used with a specific instrumentation technique. As a consequence, not only the singlecone tech- nique regained popularity due to the fact that single matched cone could now produce a sat- isfactory three-dimensional fill; also warm vertical techniques gained advantages from the use of a matched master cone, by reducing the risk of voids or gaps inside the filled endodontic space. However, the greater amount and variability in design and dimensions of commercially available NiTi instruments and GP cones of greater tapers can easily create confusion among practitioners, especially if they use instruments and cones of different brands. If selected gut- tapercha cones do not precisely match with the used NiTi instru- ments, the whole concept fails and in many cases GP cones do not reach the desired working length and/or don’t fill the apical preparation precisely. In order to appreciate how matched GP cones should work, clinicians need to understand the differences in sizes, tapers, designs and manufacturing pro- cesses of these products. Even if these factors are usually taken into account when a manufac- turer produces matched GP cones to be used with a specific instrumentation technique, the goal of the present paper is to discuss all these variables and give clinicians a better under- standing of the possible clinical problems they may encounter in the cone fitting and practical solutions to solve them. Sizes, tolerance and manufac- turing of guttapercha cones Traditionally, GP cones are hand rolled, a manufacturing process that is not very precise and con- sistent. Therefore, according to ISO standards the tolerance al- lowed for GP cones is 0.05 mm, much bigger than the tolerance allowed for endodontic instru- ments produced by grinding or twisting (0.02 mm). This has always been a problem in endo- dontics and it explains why cor- rect fitting of the master cones in all techniques (single-cone, lateral condensation, warm vertical condensation, SystemB continuous wave of obturation) is always described as a funda- mental step in the procedure. With the traditional ISO .02 ta- pered cone, the problem mainly related to the lack of precision of tip of the GP cones. Therefore GP tips needed to be manually adjustedtofittheapicalprepara- tion with a good retention (“tug back”), to avoid under filling and/or overextension of cones through the apical foramen. The same procedure was need- ed for non-standardised gut- tapercha cones with feathered tips. This is why calibres or spe- cific instruments to precisely cut gutta-percha cones were invent- ed and commercialised (Fig. 1). With the introduction of gutta- percha cones of greater tapers the problem is not only related to the tip sizes, but also to the taper. Therefore, these GP cones can be divided in two categories: uniform and non-uniform taper. The first ones are usually com- mercialised as .04 or .06 tapered cones, while the second ones are usually commercialised with a brand name related to a specific instrumentation technique (i.e. TF cones, TFA cones, etc). Tip sizes and tapers of NiTi in- struments Even if some instruments have a non-uniform taper, the great majority of endodontic NiTi ro- tary instruments have a uniform taper, and techniques are de- signed to create at least a .04/ .06 tapered preparation. This is why GP cones of greater tapers are usually commercial- ised in .04 and .06 tapers. How- ever, NiTi instruments having the same nominal size and taper may not have the same dimen- sions and consequently not cre- ate an identical root canal prep- aration, due to the fact that the length of the working part can be different. (Fig. 2.) For example, in a .06-25 K3XF the working part is 16 mm, while in a .06-25 TF instruments it is 10 mm. Even if the taper and tip sizes are the same, a .06-25 K3XF will enlarge the root canal up to 1.21 mm. This calculation can be made as follows: 0.06 increase for each mm multiplied for 16 mm = 0.96 mm + 0.25 tip size = 1.21 mm. On the contrary a .06- 25 TF instrument will enlarge the canal to a lesser extent: 0.85 mm ( 0.06 x 10 = 0.60 mm +0.25 tip size= 0.85 mm). Differences can be found be- tween any NiTi instrument with a traditional 16 mm working part compared with any with a reduced working part. NiTi in- struments with a shorter work- ing length are nowadays widely used since many canals are ac- tually not longer than 10 mm from orifice to apex; a shorter working part creates less stress- ful instrumentation by reducing taper-lock and torsional stress in the biggest part of the instru- ments: with a lower operative torque, efficiency and safety are more easily improved. Nev- ertheless, instruments with a shorter working length need GP cones with the same design and dimensions, if clinicians seek perfect matching between prepared canals and obturating materials. Matching TF/TFA instruments with GP cone The differences in dimensions previously described between K3XF and TF can be found be- tween .04-.06 GP cones and TF/ TFA GP cones. The first 9-10 mm are identical, but in the cor- onal part the .04-.06 GP cones are much wider (Fig. 3). There- fore, if clinicians try to use these cones in a 10 mm (or more) root canal prepared with TF/TFA, the GP cone probably won’t get to working length, because the greatest dimensions of the cone are in the coronal part; it could be defined as “GP taper-lock”. This is a different problem from those experienced by dentists in the past, mainly related to the cone fitting in the apical part, and consequently needing a dif- ferent approach. Choosing a smaller tip size cone maynotsolvetheproblem,while choosing a smaller tapered cone may significantly increase the risk of iatrogenic errors like un- der-filling and/or overextension of the cone through the apical foramen, because the tug-back in the coronal part does not al- low correct apical cone fitting. Therefore the best and easiest solution is to choose TF/TFA guttapercha cones that precisely fit the root canal preparation achieved by the TF/TFA instru- ments and allow ideal three-di- mensional filling and good api- cal tug-back. In the alternative, a K3XF user could use both types of cones (the .04-.06 cones and TF/TFA) because they will both nicely fit the root canal prepa- ration in the apical and middle thirds. Additional clinical tips for TF/ TFA users So far, dimensions and sizes have been discussed to help cli- nicians to understand problems in matching instruments and cones. However, there are also clinical ways to try to solve problems that can be encountered during these procedures. These are tips that can be useful not only with TF/TFA but with many instru- mentation techniques. Create more coronal flaring. TF/TFA are very efficient instru- ments and very good at lateral cutting. They are ideal instru- ments for all techniques that re- quire brushing and/or circum- ferential filing. Therefore, if a GP cones does not perfectly match the root ca- > Page 11 Alabama Dental School provid- ing dental treatments to the un- insured community in the area. Costa-Larson was a delegate in the Massachusetts Hygiene As- sociation Board. She received an associate in science in hygiene at the Springfield Community College, Bachelor of Science in business at University of Phoe- nix, Tampa, and a master’s in healthcare administration from Argosy University in Florida. Contact her at whitesmiles4y- ou@gmail or LinkedIn (Nancy Costa, Sleep Apnea Forum).