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ePaper created 2014-06-27, 16:49:13 | version 1.30.01
science & practice6 AEEDC Dubai 2014 Root canal instrumentation is one of the major tools for ensuring the long-term success of root canal therapy.1, 2 The aim is to mechani- cally disrupt as much biofilm as possible so that with the addition of irrigants and/or intra-canal medicaments a very low microbial countcanconsistentlybeachieved before the filling of the root canal. Another aim or challenge of root canalinstrumentationistoachieve the microbial reduction goals mentioned above without unnec- essarily weakening the root by over-instrumentation, for example through the reduction of the denti- nal wall thickness. Preservation of native structure, especially in the cervical region of the tooth has been demonstrated to correspond to better long-term survivability from a loading and restorative standpoint. It is well established that as the remaining dentine thickness decreases so does the root’s resistance to fracture.3 In evaluating anatomical stud- ies, it is striking that they are con- sistent. Figure 1 best summarises theanatomicalaimsforamandibu- lar molar. The mesiobuccal and mesiolingual canals are at the 1mm measurement from the api- cal foramen, which corresponds most closely to the dentinocemen- tal junction. In the mesiodistal di- rection, the diameters are 0.21 and 0.28mm respectively, thus finish- ing at a 25 file would appear to be sufficient when viewed on a peri- apical radiograph, since the mesiodistal direction is what we see on the radiograph. However, when we look in the buccolingual direction,thecorrectfilessizesare between 35 and 40. For the distal canal, a size 35 would appear ade- quateontheradiograph(mesiodis- talview)butthecorrectsizewould be 50. In order to achieve the goals mentioned above, we should aim for 35, 40 or 50 apical sizes with no more than a 0.04 taper.4–6 These bi- ological sizes with the addition of an adequate irrigation protocol will ensure a consistently low mi- crobial count for maximal success. BT-Race system BT-Race files (FKG Dentaire) are sterilised in individual blisters so that sterility is maintained for Biological and conservative root canal instrumentation with BT-Race file system By Drs Gilberto Debelian & MartinTrope Fig. 1: Median canal diameters.–Fig. 2: Benefits of Race files.–Fig. 3: The BT and normal tip: localisation of the cutting point.–Fig. 4: Efficiency of the normal tip and the BT in the canal: the path of the tip, with a guide.–Fig. 5: BT-Race sequence.– Fig. 6: BT-Race XL for finishes at sizes 40 and 50. 1 2 3 4 5 6 Figs. 7–10: Clinical cases. (Courtesy: Dr. Gilberto Debelian, Norway [Fig. 7–9] and Dr. Johan Ulstad, Norway [Fig. 10]) 7 8 9 10