Evaluation Of The Risk Of A Stripping Perforation With Gates-glidden Drills: Serial Versus Crown-down Sequences

The aim of this study was to evaluatte the remaining dentine/cementum thickness using Gates-Glidden burs in serial and crown-down sequences and to observe which of the two sequences is the safest for preparing mesial roots of molars. Thirty-six left and. right human mandibular first molars were selected. Standard access cavities were made and initially explored with Flexofiles sizes 10 and 15 until the tip was visible at the apex. The teeth were embedded in a muffle speqially developed for this study using a PVC tube with two parallel metal rods An its lid. Each tooth-block was sectioned 3 mm apically to the furcation using a low-speed saw with a diamond disc. The tooth-block was examined under a microscope and an initial image was captured by a digital video system with 8 X and 12 X magnifications. Finally, the tooth-blocks were reassembled in the muffle so that the canals could be instrumented. After instrumentation the area of each mesial canal as well as the smallest distance to the root furcation were measured again. The mesio-buccal canals (crown-down order) and the mesio-lingual canals (serial sequence) presented an average area of 0.46 ± 0.16 mm2 and 0.88 ± 0.27 mm2 (P < 0.01), respectively. The mean values of the smallest distance to the furcation for the mesio-buccal and mesio-lingual canals were 0.66 ± 0.19 mm and 0.39 ± 0.13 mm (P < 0.01), respectively. The remaining dentine/cementum thickness using Gates-Glidden burs was greater in the crown-down sequence than in the serial sequence.2211824Grossman, L., A brief history of endodontics (1982) J Endod, 8 (1), p. 538Mullaney TP. Instrumentation of finely curved canals. Dent Clin North Am. l979;23(4):575-92Taintor, J.F., Use of the gates glidden bur in endodontics (1978) J Nebr Dent Assoc, 54 (3), pp. 10-12Weine, F.S., Kelly, R.E., Lio, P.J., The effect of preparation procedures on original canal shape and on apical foramen shape (1975) J Endod, 1 (8), pp. 255-262Abou-Rass, M., Frank, A.L., Glick, D.H., The anticurvature filing method to prepare the curved root canal (1980) J Am Dent Assoc, 101 (5), pp. 792-794Cunningham, C.J., Senia, S.E., A three-dimensional study of canal curvatures in the mesial roots of mandibular molars (1992) J Endod, 18 (6), pp. 294-300Coutinho-Filho.T, De-Deus G, Guimarães T, Gurgel-Filho ED, Maniglia-Ferreira C. A computer evaluation of the dentin remaining after cervical preparation in curved canals: Gatesglidden drills vs. orifice shaper. Braz J Oral Sci. 2002;1(3):116-20Lim, S.S., Stock, C.J., The risk of perforation in the curved canal: Anticurvature filing compared with the step-back technique (1987) Int Endod J, 20 (1), pp. 33-39Isom, T.L., Marshall, J.G., Baumgartner, J.C., Evaluation of root thickness in curved canals after flaring (1995) J Endod, 21 (7), pp. 368-371Gluskin, A.H., Brown, D.C., Buchanan, L.S., A reconstructed computerized tomographic comparison of Ni-Ti rotary GT files versus traditional instruments in canals shaped by novice operators (2001) Int Endod J, 34 (6), pp. 476-484Schilder, H., Cleaning and shaping the root canal (1974) Dent Clin North Am, 18 (2), pp. 269-296Bramante, C.M., Berbet, A., Borges, R.P., A methodology for evaluation of root canal instrumentation (1987) J Endod, 13 (5), pp. 243-245Bower, R.C., Furcation morphology relative to periodontal treatment. Furcation entrance architecture (1979) J Periodontol, 50 (1), pp. 23-27Kessler, J.R., Peters, D.D., Lorton, L., Comparison of the relative risk of molar root perforations using various endodontic instrumentation techniques (1983) J Endod, 9 (10), pp. 439-447McCann, J.T., Keller, D.L., LaBounty, G.L., A modification of the muffle model system to study root canal morphology (1990) J Endod, 16 (3), pp. 114-115Pilo, R., Corcino, G., Tamse, A., Residual dentin thickness in mandibular premolars prepared with hand and rotatory instruments (1998) J Endod, 24 (6), pp. 401-404Torabinejad, M., Rotstein, L., Stabholz, A., Effect of preflaring on tactile detection of the apical constriction (1995) J Endod, 21 (2), pp. 92-94West JD, Roane JB. Limpeza e modelagem do sistema de canais radiculares. In: Cohen S, Burns RC. Caminhos da polpa. 7th ed. Rio de Janeiro: Guanabara Koogan2000. p. 206-36Abou-Rass, M., Jastrab, R.J., The use of rotary instruments as auxiliary aids to root canal preparation of molars (1982) J Endod, 8 (2), pp. 78-7

Chemical Composition And Thermal Behavior Of Five Brands Of Thermoplasticized Gutta-percha

Objective: The aim of this study was determine the chemical composition and thermal behavior of Thermafil(TH), Microseal Cone (MC), Microseal Microflow (MF), Obtura (OB) and Obtura Flow (OF). In addition, their thermal behavior in response to temperature variations was studied by differential scanning calorimetry (DSC) to determine the temperature at which gutta-percha switches from the beta to alpha form, and from the alpha to the amorphous phase. Materials and Methods: The organic and inorganic fractions were separated by dissolution in chloroform. Gutta-percha (GP) was precipitated with acetone. The inorganic fraction was analyzed via Elemental Microanalysis. Energy Dispersive X-ray Microanalysis and X-ray Diffraction were used to identify the chemical elements and compounds (BaSO4 and ZnO). Thermal analysis was conducted using DSC. Results: The organic and inorganic fractions ranged from 21.3% and 26.9% of weights, respectively. MC and MF showed the highest percentages of organic compounds (P = 0.0125). All specimens exhibited two crystalline transformations when heated from ambient temperature to 130°C. MC presented the highest percentage of GP. Conclusions: No correlation was observed between chemical composition and thermal behavior. Each of the products showed thermal behavior that is typical of beta-phase gutta-percha. © 2013 Dental Investigations Society.72201206Anbu, R., Nandini, S., Velmurugan, N., Volumetric analysis of root fillings using spiral computed tomography: An in vitro study (2012) Int Endod J, 43, pp. 64-68Goldberg, F., Artaza, L.P., Silvio, A., Efectiveness of different obturation techniques in the filling of simulated lateral canals (2001) J Endod, 27, pp. 362-364Gurgel-Filho, E.D., Feitosa, J.P., Gomes, B.P., Ferraz, C.C., Souza-Filho, F.J., Teixeira, F.B., Assessment of different gutta-percha brands during the filling of simulated lateral canals (2006) Int Endod J, 39, pp. 113-118Tanomaru-Filho, M., Pinto, R.V., Bosso, R., Nascimento, C.A., Berbert, F.L., Guerreiro-Tanomaru, J.L., Evaluation of the thermoplasticity of gutta-percha and Resilon(®) using the Obtura II System at different temperature settings (2011) Int Endod J, 44, pp. 764-768De Deus, G.A., Gurgel-Filho, E.D., Maniglia-Ferreira, C., Coutinho-Filho, T., Penetração intradentinária de quatro cimentos endodônticos (2002) Braz Oral Res, 16, p. 332Friedman, C.E., Sandrick, J.L., Heuer, M.A., Rapp, G.W., Composition and physical properties of gutta-percha endodontics filling materials (1977) J Endod, 3, pp. 304-308Ozawa, T., Taha, N., Messer, H.H., A comparison of techniques for obturating oval-shaped root canals (2009) Dent Mat J, 28, pp. 290-294Brosco, V.H., Bernardineli, N., Torres, S.A., Consolaro, A., Bramante, C.M., Moraes, I.G., Bacterial leakage in obturated root canals-part 2 A comparative histologic and microbiologic analyses (2010) Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 109, pp. 788-794Chandrasekhar, V., Morishetty, P.K., Metla, S.L., Raju, R.V., Expansion of gutta-percha in contact with various concentrations of zinc oxide-eugenol sealer: A three-dimensional volumetric study (2011) J Endod, 37, pp. 697-700Schilder, H., Filling root canals in three dimensions (1967) Dent Clin North Am, 11, pp. 723-744Goodman, A., Schilder, H., Aldrich, W., The thermomechanical properties of guta-percha: II: The history and molecular chemistry of guta-percha (1974) Oral Surg Oral Med Oral Pathol, 37, pp. 954-961Cohen, B.D., Combe, E.C., Lilley, J.D., Effect of thermal placement techniques on some physical properties of dental gutta-percha (1992) Int Endod J, 25, pp. 292-296Maniglia-Ferreira, C., Valverde, G.B., Silva, J.B., Paula, R.C., Feitosa, J.P., Souza-Filho, F.J., Clinical relevance of trans 1, 4-polyisoprene aging degradation on the longevity of root canal treatment (2007) Braz Dent J, 18, pp. 97-101Schilder, H., Goodman, A., Aldrich, W., The thermomechanical properties of gutta-percha Part V. Volume changes in bulk gutta-percha as a function of temperature and its relationship to molecular phase transformation (1985) Oral Surg Oral Med Oral Pathol, 59, pp. 285-296Gurney, B.F., Best, E.J., Gervasio, E., Physical measurements on gutta-percha (1971) Oral Surg Oral Med Oral Pathol, 32, pp. 260-270Marciano, J., Michailesco, P.M., Abadie, J.M., Stereochemical structure characterization of dental gutta-percha (1993) J Endod, 19, pp. 31-34Marciano, J., Michailesco, P.M., Charpentier, E., Carrera, L., Abadie, J.M., Thermomechanical analysis of dental gutta-percha (1992) J Endod, 18, pp. 263-270Schilder, H., Goodman, A., Aldrich, W., The thermomechanical properties of gutta-percha III: Determination of phase transition temperatures for gutta-percha (1974) Oral Surg Oral Med Oral Pathol, 38, pp. 109-114Maniglia-Ferreira, C., Gurgel-Filho, E.D., Silva, J.B., Paula, R.C., Feitosa, J.P., Gomes, B.P., Brazilian gutta-percha points Part II: thermal properties (2007) Braz Oral Res, 21, pp. 29-34Marciano, J., Michailesco, P.M., Dental gutta-percha: Chemical composition, X-ray identification, enthalpic studies and clinical implications (1989) J Endod, 15, pp. 149-153Combe, E.C., Cohen, B.D., Cummings, K., Alpha-and beta-forms of gutta-percha in products for root canal filling (2001) Int Endod J, 34, pp. 447-451Gurgel-Filho, E.D., Feitosa, J.P., Teixeira, F.B., Paula, R.C., Silva, J.B., Souza-Filho, F.J., Chemical and X-ray analyses of five brands of dental gutta-percha cone (2003) Int Endod J, 36, pp. 302-307Möller, B., Ørstavik, D., Chemical and Energy Dispersive X-ray analyses of gutta-percha points (1984) J Endod, 10, pp. 413-416Lyman, C.E., Goldstein, J.I., Romig, A.D., Echlin, P., Joy, D.C., Newbury, D.E., Scanning electron microscopy, X-ray microanalysis, and analytical electron microscopy (1990), pp. 33-41. , New York, NY: Plenum Press;Maniglia-Ferreira, C., Silva Jr, J.B., Paula, R.C., Feitosa, J.P., Cortez, D.G., Zaia, A.A., Brazilian gutta-percha points Part I: Chemical composition and X-ray diffraction analysis (2005) Braz Oral Res, 19, pp. 193-197Budavari, S., O'Neil, M.J., Smith, A., Heckelman, P.E., Kinneary, J., (1996) Merck index, , 12nd ed. New Jersey: Merck and Co Inc. ;Maniglia-Ferreira, C., Valverde, G.B., Silva, J.B., Paula, R.C., Feitosa, J.P., Souza-Filho, F.J., Degradation of trans-polyisoprene after root filling with thermoplasticized techniques (2008) Int Endod J, 41, pp. 296-302Stevens, M.P., Polymer chemistry, an introduction (1999), New York: Oxford University Press;Ivan, G., Meghea, A., Giurginka, M., Iftimie, N., Thermo-oxidative degradation of some elastomers with a high content of 3,4 isoprene units (2003) Pol Degrad Stab, 80, pp. 397-402Silva, J.B.A., Paula, R.C., Feitosa, J.P., Gurgel-Filho, E.D., Maniglia-Ferreira, C., Souza-Filho, F.J., vivo aging of gutta-percha endodontic cone (2006) J Appl Pol Sc, 100, pp. 4082-4088Maniglia-Ferreira, C., Almeida-Gomes, F., Sousa, B.C., Lins, C.C., Santos, R.A., A case of unusual anatomy in second mandibular molar with four canals (2008) Eur J Dent, 2, pp. 217-21

Vertical Root Fracture Detection Using Computed Tomography In The Presence Or Absence Of Metallic Cores [deteção De Fratura Radicular Vertical Utilizando Tomografia Computadorizada Na Presença Ou Ausência De Núcleos Metálicos]

The objectives were: (1)test accuracy of CT in detection of vertical root fracture and (2) investigate the influence of the metallic post in detection of vertical root fracture. Four teeth with vertical root fractures were selected and tested in four conditions determined by the presence or absence of metallic post and location of fracture. Two teeth without fracture were used as controls, one receiving metallic post. These teeth were inserted into a jaw and underwent a CT scan. The results were interpreted by ten radiologists by the presence or absence of fractures. The results showed an inconsistency in interpretation of fractures, having been found a greater number of false-positive results (10%) and false negatives (53.3%) that the accurate diagnosis of fractures (37.6%). Can still be seen less accurate diagnosis of these fractures in teeth that had metallic posts than in teeth that did not. © 2011 Sociedade Portuguesa de Estomatologia e Medicina Dentária.5329698Liapatas, S., Nakou, M., Rontogianni, D., Inflammatory infiltrate of chronic periradicular lesions: an immunohistochemical study (2003) Int Endod J, 36, pp. 464-471Cohen, S., Berman, L.H., Lucia, B., Bakland, L., Kim, J.S., A Demographic Analysis of Vertical Root Fractures (2006) J Endod, 32, pp. 1160-1163Mora, M.A., Mol, A., Tyndall, D.A., Rivera, E.M., In vitro assessment of local computed tomography for the detection of longitudinal tooth fractures (2007) Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 36, pp. 825-829Hassan, B., Metska, M.E., Ozok, A.R., Van del Stelt, P., Wellelink, P.R., Detection of vertical root fractures in endodontically treated teeth by cone beam computed tomography (2009) J Endod, 35, pp. 719-722Fuss, Z., Lusting, J., Ganor, Y., Kaffle, I., Radiografic featured, endondontically treated maxillary premolars (1999) Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 88, pp. 348-352Kamburoglu, K., Cebeci, A.R.I., Grondahl, H.G., Effectiveness of limited cone-beam computed tomography in the detection of horizontal root fracture (2009) Dent Traumatol, 25, pp. 256-261Wenzel, A., Haiter-Neto, F., Frydenberg, M., Kirkevang, L.L., Variable-resolution cone-beam computerized tomography with enhancement filtration compared with intraoral photostimulable phosphor radiography in detection of transverse root fractures in an in vitro model (2009) Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 108, pp. 939-945Ozer, S.Y., Detection of vertical root fractures by using cone beam computed tomography with variable voxel sizes in an in vitro model (2011) J Endod, 37, pp. 75-79Bernades, R.A., De Moraes, I.G., Húngaro Duarte, M.A., Azevedo, B.C., De Azevedo, J.R., Bramante, C.M., Use of cone-beam volumetric tomography in the diagnosis of root fractures. (2009) Oral Surg Oral Med Oral Pathol Oral Radiol Endod., 108, pp. 270-7Costa, F.F., Gaia, B.F., Umetsubo, O.S., Paraiso Cavalcanti, M.G., Detection of horizontal root fracture with small-volume cone-beam computed tomography in the presence and absence of intracanal metallic post (2011) J Endod, 37, pp. 1456-145