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Revista Facultad de Odontología Universidad de Antioquia
Print version ISSN 0121-246X
Rev Fac Odontol Univ Antioq vol.23 no.1 Medellín July/Dec. 2011
ORIGINAL ARTICLES DERIVED FROM RESEARCH
Scanning electron microscopy analysis of two endodontically treated teeth subjected to high temperatures. A pilot study
Freddy Moreno Gómez1, Carlos Mejía Pavony2
1 Dentist. Professor at the Escuela de Odontología of Universidad del
Valle. Student of the MA on Biomedical Sciences at Escuela de Ciencias
Básicas, Facultad de Salud, Universidad del Valle. Research Group on
Oral and Maxillofacial Surgery, Escuela de Odontología, Facultad de
Salud, Universidad del Valle
2 Dentist. Magister on Morphology. Escuela de Ciencias Básicas, Facultad
de Salud, Universidad del Valle. Professor at the Escuela de Odontología
of Universidad del Valle. Research Group on Soft and Mineralized
Tissues, Escuela de Ciencias Básicas, Facultad de Salud, Universidad
del Valle
RECIBIDO: NOVIEMBRE 16/2010-ACEPTADO: AGOSTO 30/2011
CORRESPONDING AUTHOR
Freddy Moreno Gómez
PBX: 554 24 69. Fax: 558 19 41
Cell phone #: 311 307 0410
E-mail address: freddymg@univalle.edu.co
Universidad del Valle
Escuela de Odontología
Calle 4B N.° 36-00 Edificio 132 Oficina 308
Cali, Colombia
Moreno F, Mejía C. Scanning electron microscopy analysis of two endodontically treated teeth subjected to high temperatures. A pilot study. Rev Fac Odontol Univ Antioq 2011; 23(1): 22-36.
ABSTRACT
INTRODUCTION: the objective of this study was to describe the physicochemical changes occurring in dental tissues and
materials used in a conventional endodontic treatment when subjected to high temperatures, by means of scanning electron microscopy
(SEM)
METHODS: in vitro, two human premolar teeth were subjected to temperatures of 200°C and 400°C respectively, with the purpose of
standardizing a technique for the observation of physical and chemical changes in dental tissues (enamel and dentin) and dental materials
commonly used in endodontic treatment (root canal gutta-percha and epoxy resin-based endodontic cement).
RESULTS: both the tissues
and the dental materials analyzed in this pilot study presented great resistance to high temperatures without significantly changing their
macrostructure; therefore, the physical changes (dimensional stability, cracks, crevices, fractures, texture, carbonization) and the chemical
ones (constituent chemical elements) may turn out to be identifiable and associated with each specific temperature range by means of SEM
and spectrophotometric analysis.
CONCLUSIONS: dental tissues and materials display great resistance to the action of high temperatures,
without significantly altering their macrostructure. Similarly, they experience physical and chemical changes that may contribute to the
process of identification of a corpse or human remains that have been burned, incinerated or charred.
Key words: forensic dentistry, human identification, dental tissues, dental material of endodontic use, high temperatures, scanning electron microscopy (SEM), spectrophotometry.
INTRODUCTION
Several studies among the specialized literature have described the changes of teeth when subjected to high temperatures with forensic purposes. Some of the most relevant studies are the ones carried out by the Unit of Dental Materials of the University of Pavia’s Department of Odontostomatology (Italy);1-3 the ones performed by the Laboratory of Forensic Dentistry of the Universidad de Zulia’s School of Dentistry Research Institute (Venezuela);4-6 the in vitro studies on resin-based materials subjected to high temperatures, carried out by the Department of Restorative Dentistry of the State University of New York at Buffalo’s School of Dental Medicine,7-9 as well as the recent findings by the Research Group on Oral and Maxillofacial Surgery from the Universidad del Valle’s Facultad de Odontología (Colombia), which has been focusing on the macroscopic, stereomicroscopic, microscopic, radiographic, and tomographic studies on the behavior of dental tissues and materials when subjected to high temperatures. Thus, several reports describe the macro- and microstructural physical changes, which include dimensional stability, cracks, crevices, fractures, texture, color, carbonization, and incineration of dental tissues in intact teeth,10 as well as some materials used in dental operations,11 and of endodontic use.12
Nevertheless, it is necessary to conduct new studies using different kinds of analysis including histology, atomic force microscopy, spectrophotometry, scanning electron microscopy, and the like, which would explain the macrostructural changes based on the microstructural ones; accordingly, it would be appropriate to analyze the behavior of the interfaces between dental tissues (enamel-dentin, enamelcementum, and dentin-cementum), between the materials of dental use (amalgam-glass ionomer, resin-glass ionomer, and obturation cement-guttapercha), and between dental tissues and materials of dental use (enamel-amalgam, enamel-resin, dentinamalgam, dentin-resin, obturation cement-dentin), for which it would be necessary to standardize the procedures of temperature application and observation, by means of scanning electron microscopy.
Describing the physical and chemical changes of tissues and dental materials used for conventional endodontic treatments when subjected to high temperatures, by means of scanning electron microscopy, this would also establish an important starting point for investigations that include larger samples, different materials of dental use, and different temperature ranges, in order to demonstrate that scanning electron microscopy analysis and spectrophotometry may contribute to the generation of new knowledge in the field of identification in the legal, clinical, technical, and scientific activity of forensic dentistry.
MATERIALS AND METHODS
This is an in vitro experimental pilot study on the behavior of the influence of high temperatures on dental tissues (enamel and dentin) and some materials of dental use (GS80® SDI® silver amalgam, Point 4® Kerr® resin, Fuji® GC America® glass ionomer, Maillefer Dentsply® gutta-percha, Top Seal® Dentsply® endodontic epoxy resin, and Grossfar® Eufar® oxide of zinc eugenol-based endodontic cement). For this purpose, two singlerooted premolars (a first lower left premolar −tooth 1− and a first lower right premolar −tooth 2−) were conveniently chosen as being recently extracted for orthodontic reasons, and not having cavities, restorations, endodontic treatments, pulpal pathologies, or congenital malformations.
The variables used in this study correspond to the microscopic changes observed, by means of scanning electron microscopy, in both dental tissues and materials used to obturate the pulpal canal and the access cavity during an endodontic treatment, in correlation to the macroscopic changes identified by means of digital photography. In order to make the discussion easier, these changes will be classified according to tissues, dental materials, and temperature ranges, having into account: 1. Maladaptation of obturation materials; 2. Cracks, crevices, fractures, and a broken aspect; 3. Texture changes, and 4. Levels of carbonization and incineration.
Sample Collection
The two teeth were obtained during the project “In vitro macroscopic analysis of dental tissues and some dental materials of endodontic use subjected to high temperatures for forensic purposes”, which was endorsed by the Institutional Committee of Human Ethics Revision of Universidad del Valle’s School of Health, following Article 11 of Resolution N° 008430 of the Ministerio de la Protección Social (Colombia),13 and the ethical principles for medical research specified by the World Medical Association at the Helsinki Declaration.14 Once the authorization of the School of Dentistry’s, Administration was granted, as well as a letter of consent signed by the patients, the sample was obtained from the teeth extracted at the Clinic of Oral Surgery of the Universidad del Valle’s School of Dentistry, provided that they met the terms of inclusion.
Handling and conservation of the sample
Right after extracting the teeth, they were washed with non-sterile water in order to eliminate blood deposits, and they were placed in a dark recipient with fixing solution 5% Chloramine T (100 gr Tosyl Chloramide sodium dissolved in 2 liters of distilled water) for a week. The teeth were then stored in a saline solution at a temperature of 37°C with a relative humidity of 100%; the saline solution was changed every two weeks, following ICONTEC standards 4882/200015 and ISO/TS 11405/2003,16 until the procedures were initiated.
Preparation of the cavities
A single operator placed each of the teeth in a wax base, and proceeded to make an occlusal cavity Type I on them, following the access indications provided by the endodontic literature, with a depth that would allow pulp chamber display, by using a high speed handpiece (NSK®) with constant refrigeration and pear diamond burs of medium to fine grain (Diatech®). Once the cavities had been made, each tooth was cleansed with oxygenated water to disinfect the cavities and to reduce dentine superficial tension, in order to optimize the resin composite adhesive properties.17
Endodontic treatment
A conventional endodontic treatment was performed consistent with the telescopic technique. Once the canal was found, the master apical file was located and conductometry was conducted at approximately 2 mm of the apical foramen. Instrumentation of the canal started with files of the first series, one by one in their right order, decreasing the working length for each file 2 mm in relation to the apex, irrigating with sodium hypochlorite, and reiterating with the master apical file between each file. Once the canal biomechanical preparation had been completed, a conometrical measurement was performed with a gutta-percha cone of the same diameter and working length, determined by the last file with which it had been instrumented; finally, obturation of the canal was initiated by using the technique of gutta-percha cone condensation and obturation cement. Once obturation had been verified, the cone crests were cut 2 mm under the cementoenamel junction line, and a Fuji® GC America® glass ionomer seal was applied.
Obturation of the cavities
This was done according to the dental material used for filling the cavity:
Tooth 1
This tooth was endodontically treated as described, and its canal was obturated with Maillefer Dentsply® gutta-percha and Top Seal Dentsply® epoxy resin cement; it was sealed with Fuji® GC América® glass ionomer. The cavity was filled with Point 4® Kerr® resin by means of the enamel acid etching technique for 15 seconds and dentine conditioning for 10 seconds with 37,5% phosphoric acid (Gel Etchant® Kerr®). An adhesive (OptiBond Solo Plus® Kerr®) was applied with a microbrush in two layers: the first one was left to impregnate for 20 seconds by an indirect jet of air for 5 seconds, so that the adhesive would penetrate the dentinal tubules, and the second one was used to smooth the surface avoiding dry zones. The adhesive agent was polymerized for 40 seconds with a photo-polymerization lamp (Spectrum 800® Dentsply®). Finally, the composite resin (Point 4® Kerr®) was packed by means of the oblique layering technique; each oblique layer was polymerized for 40 seconds with the same photopolymerization lamp until completely filling the cavity.The process was finished by polishing and brightening the restoration, in order to eliminate the obstructed superficial layer, with the Hiluster Plus® and Occlubrush systems.
Tooth 2
This tooth was endodontically treated as described, and its canal was filled with Maillefer Dentsply® gutta-percha and Eufar® zinc oxide eugenol cement; it was sealed with Fuji® GC America® glass ionomer. The cavity was obturated with GS80® SDI® silver amalgam by means of the conventional technique of packing, condensing, burnishing and polishing the restoration.
Application of high temperatures
Once the obturations had been completed, both teeth were taken to individual trays made of refractory lining material (Cera Fina® Whipmix®) in order to easily manipulate them according to the prototype patented by the Unit of Dental Materials of the University of Pavia’s Department of Odontoestomatology (Italy); they were also subjected to direct heat inside a muffle furnace (Thermolyne®), which was previously calibrated to two temperatures (initially 200°C –tooth 1– and then 400°C –tooth 2–) with an increase rate of 10°C per minute, initiating with a temperature of 34°C (room temperature) until reaching each of the indicated temperatures. Once the specific temperatures had been applied, the teeth were removed from the furnace. When they cooled down, they were sprinkled with hairspray in order to provide them with some level of resistance and to facilitate their handling.18
Macroscopic observation
One of the examiners observed and described the macrostructual changes of dental tissues and obturation materials by direct observation of the sample and by using digital photographs of 20x (digital camera Sony® Cyber Shot® DSC-H50 of 8.1 megapixels and a 35 mm Carl Zeiss lens), in accordance with the variables used for this study. The samples were later embedded in transparent acrylic (New Estethic®) and they were scoured (WhipMix® trimmer) in a sagittal direction, in order to display the endodontic treatment and to observe the changes of tissues and dental materials in a macroscopic way.
Microscopic observation
The incisions were coated with a gold layer and observed by Scanning Electron Microscopy (SEM), using a JEOL® JSM 6490 LV® microscope belonging to the Escuela de Ingeniería de Materiales (EIMAT) of the Universidad del Valle’s Facultad de Ingeniería, which source of electrons is a tungsten W filament with a voltage acceleration ranging from 0,3 kV to 30 KV. At a high-vacuum operation mode it reached a resolution of 3 nm with high voltage acceleration in secondary electron mode, and 4 nm at a backscattered electron mode with low-vacuum. Similarly, the SEM’s spectrometer was used for a detailed chemical analysis of the enamel and the endodontic obturation materials.
RESULTS
At a temperature of 200°C the crowns of both teeth turn brownish, with a white incisal edge. In the sagittal section, the bond interface between the enamel and the dentin all along the crown turns brownish; the crown takes this color because of the enamel being translucent (figures 1A and 1B).In relation to the materials of dental use, at a temperature of 200°C the resin takes a light brown color and displays marginal maladaptation, as well as superficial fissures and cracks. In the sagittal sections, the oxide of zinc eugenol-based obturation cement can be seen between the gutta-percha cones without significant changes; and the gutta-percha, melted by the heat, seeps through the apical hole and keeps its original color (figures 1A and 2B).
The microphotographs of tooth 1, obtained with the scanning electron microscope, clearly show the melted aspect of the gutta-percha in the root’s coronal third and in the middle radicular third, where the obturation cement can be recognized (figures 1C to 1F).
At a temperature of 400°C the crown takes a darker tone, the remaining bacterial plaque carbonizes, and the enamel of the entire crown cracks and blasts at the cervical zone. The dentin turns black due to carbonization, and enamel-dentin separation occurs due to internal fractures, especially in the cervical third (figures 2A and 2B).
(figure 1)
(figure 2)
At this temperature, the amalgam suffers marginal maladaptation and becomes opaque and rough because of the formation of nodules in its surface due to mercury evaporation. Both the obturation cement and the gutta-percha, both white, incinerate and it is not possible to differentiate them macroscopically.
At 200°C and 400°C the glass ionomer remains intact but detached from the obturation material and the gutta-percha (figures 3A and 3B). Longitudinal and transversal deterioration of the dentinal tubules may also be verified (figura 3C to 3F).
Similarly, by means of scanning electron microphotographs it is possible to determine the diverse chemical elements that compose both materials; figures 3A and 3B show high concentrations of calcium, a chemical element compatible with the dentin’s inorganic matrix and with epoxy resin obturation cement, as well as zinc, platinum, barium, and titanium, which are compatible with gutta-percha components and provide it with radiopacity properties. Also, the spectrophotometric chemical analysis proves big concentrations of chemical elements such as calcium, magnesium, sodium, chlorine, and potassium, which are distinctive ions of the enamels’ inorganic matrix (figure 4).
(figura 3)
DISCUSSION
This in vitro pilot study demonstrates how dental tissues and materials of dental use resist the action of high temperatures and undergo specific changes under each of the temperatures to which they were subjected. It is important to point out that these changes may vary in vivo due to extrinsic factors such as time of exposure to the thermic attack, nature of the cause of the fire, involvement of combustion substances, temperature elevation curve, and the substances used to extinguish the fire, as well as intrinsic factors such as the thermal expansion coefficient of tissues and materials, and the point of fusion of the later. In situ, however, teeth (especially the posterior ones) are not directly exposed to fire because they are protected by perioral tissues, facial musculature and, in the case of roots, by all the protective periodontium and the osseous cortical layers of basal, maxillary and mandibular bones.19-22
Changes in dental tissues
One of the most distinctive changes of dental tissues is the enamel shattering at the cervical region. This phenomenon happens because the dentin, having abundant organic contents and 12% of water,23 shrinks because of dehydration when subjected to high temperatures. This provides it with certain level of resistance in comparison to the enamel, which has abundant inorganic content (between 96 and 99%), expressed in a mineral structure composed by a great amount of calcium phosphate in the form of apatite crystals;24 therefore, when this tissue is subjected to high temperatures, it loses its small amount of water and collagen, producing a strong contraction that generates fissures, cracks and fractures. This discrepancy in the dimensional stability causes enamel fractures in the cervical third at 200°C and dentin separation at 400°C. All these changes were reported by Günther and Schmidt?cited by Rötzscher et al,25 Merlati et al,1 and Moreno et al−.10
In terms of fissures, cracks, fractures and a broken aspect of dental tissues, some fissures appear in the enamel at 400°C, which go as deep as the coronal dentin. This pattern of longitudinal and transversal fissures and cracks makes both the enamel surface and the cementum take a broken aspect, just as Merlati et al1 and Moreno et al described it. 10
Changes in dental materials
At 200°C, the resin starts the process of carbonization by combustion of the acrylic matrix. This change was reported by Merlati et al1 and Moreno et al.10 In terms of the amalgam, the changes on its surface texture and its structure are related to the melting points of the metals that make part of the alloy. At 400°C the occlusal surface of the amalgam becomes bumpy due to the emergence of nodules because of mercury evaporating through gaseous bubbles. When temperature decreases due to the action of atmospheric pressure, these bubbles gather the materials dragged by the mercury in the nodules. This condition was also reported by Merlati et al,1 Moreno et al,11 Günther and Schmidt −cited by Rötzscher et al−,25 and Patidar et al.26
The glass ionomer suffers the same changes reported by Moreno et al,11 but they do not occur in all the samples due in part to the thickness of the material according to its functions as pulpal protector, cavity base and coronal seal of the endodontic treatment.
In terms of endodontic obturation materials, the literature does not include reports discussing the behavior of the kinds of endodontic cement used in this study. That’s why the discussion will focus on gutta-percha. This thermoplastic material is characterized for having a soft consistency between 25°C and 30°C, and a fluid one from 60°C on. These characteristics can be observed in vitro; nevertheless, López et al27 indicate that gutta-percha can resist high external temperatures in vivo, and this agrees with the study by Savio et al.3
Spectrophotometry
A standard endodontic treatment consists of a tridimensional obturation of the radicular conduct(s) with biocompatible, insoluble, thermoplastic and radiopaque materials in order to separate the external environment (periodontal tissue) from the internal one (radicular canal). This is done by using gutta-percha −an isoprene polymer composed of gutta-percha (20%), waxes (3%), zinc oxide (66%), heavy metals (11%), and coloring− as well as different zinc oxide or resin cements.28
In the case of individuals whose corpse or human remains have been charred, carbonized or incinerated, when subjected to high temperatures the perioral tissues (epidermis, dermis, facial muscles), periodontal tissues (enamel, alveolar bone, periodontal ligament) and dental tissues (enamel, dentin, cementum) behave as insulating agents or protective factors of the materials used for canals obturation during an endodontic treatment. This offers valuable information about the endodontic treatment based on both physical description and chemical components, which may be used during the comparisons between postmortem records and the antemortem information collected during a process of dental identification.
Bonavilla et al29 conducted a study by means of scanning electron microscopy and spectrophotometry, in which they examined the obturation materials of endodontically treated human teeth subjected to high temperatures, finding out extensive concentrations of heavy metals such as barium, zinc, ytterbium, strontium, and silicates, all of which are components of gutta-percha and provide it with the radiopaque characteristics that are required for its clinical use.
Similarly, in this pilot study significant remnants of zinc, platinum, barium, and titanium were found in the teeth subjected to 400° C. All of these metals are compatible with components of the gutta-percha used and provide it with its radiopaque properties.
CONCLUSIONS AND RECOMMENDATIONS
Both dental tissues (enamel, dentin and cementum) and the diverse materials used in endodontic treatment and in dental operations undergo a series of specific changes under each temperature (texture, fissures, cracks, fractures, fragmentation); therefore, their macro- and microscopic behavior offer valuable information about the temperature ranges analyzed.
The chemical analysis of both teeth subjected to high temperatures in vitro, by means of spectrophotometry, allows identification of the components of the materials of dental use after exposition to higher temperatures. This may become a valuable tool of forensic use during the procedures of dental identification of charred, carbonized or incinerated corpses.
The preliminary findings of this pilot study, which makes part of the research field of Dental Anthropology and Forensic Dentistry of the Research Group on Oral and Maxillofacial Surgery of Universidad del Valle’s Escuela de Odontología, in a strategic alliance of scientific cooperation with the Research Group on Soft and Mineralized Tissues of the Universidad del Valle’s Escuela de Ciencias Básicas, express the need of more detailed studies with a greater amount of samples and higher temperature ranges that would allow an analysis of dental tissues and materials of dental use by means of scanning electron microscopy and mass spectrophotometry (since the scanning electron microscope spectrophotometric depth field is too small and too specific).
Nevertheless, standardization of the technique to manipulate and observe human teeth in in vitro studies with high temperatures has been presented here.
1. Merlati G, Savio C, Danesino P, Fassina G, Menghini P. Further Study of restored and unrestored teeth subjected to high temperatures. J Forensic Odontostomatol 2004; 22: 17-24. [ Links ]
2. Mazza A, Merlati G, Savio C, Fassina G, Menghini P, Danesino P. Observations on dental structures when placed in contact with acids: Experimental studies to aid identification processes. J Forensic Sci 2005; 50: 406-410. [ Links ]
3. Savio C, Merlati G, Danesino P, Fassina G, Menghini P. Radiographic evaluation of teeth subjected to high temperatures: Experimental study to aid identification processes. Forensic Sci Int 2006; 158: 108-116. [ Links ]
4. Espina A, Barrios F, Ortega A, Mavarez M, Espina O, Ferreira J. Cambios estructurales en los tejidos dentales duros por acción del fuego directo, según edad cronológica. Cien Odontol 2004; 1: 38-51. [ Links ]
5. Ferreira JL, Espina AL, Barrios FA, Mavarez MG. Conservación de las estructuras orales y faciales del cadáver quemado. Cien Odontol 2005; 2: 58-65. [ Links ]
6. Ferreira JL, Espina de Fereira A, Ortega AI. Methods for the analysis of hard dental tissues exposed to high temperatures. Forensic Sci Int 2008; 178: 119-124. [ Links ]
7. Bush MA, Bush PJ, Miller RG. Detection and classification of composite resins in incinerated teeth for forensic purposes. J Forensic Sci 2006; 51(3): 636-642. [ Links ]
8. Bush MA, Miller RG, Prutsman-Pfeiffer J, Bush PJ. Identification through X-ray fluorescence analysis of dental restorative resin materials: A comprehensive study of noncremated, cremated, and processed-cremated individuals. J Forensic Sci 2007; 52(1): 157-165. [ Links ]
9. Bush MA, Miller RG, Norrlander AL, Bush PJ. Analytical survey of restorative resins by SEM/EDS and XRF: databases for forensic purposes. J Forensic Sci 2008; 53(2): 419-425. [ Links ]
10. Moreno S, León ME, Marín L, Moreno F. Comportamiento de los tejidos dentales y de algunos materiales de obturación dental sometidos a altas temperaturas con fines forenses. Colomb Med 2008; 39(1): 28-46. [ Links ]
11. Moreno S, Marín L, Merlati G, Savio C, Moreno F. Effects of high temperatures on different dental restorative systems: experimental study to aid identification processes. J Forensic Dent Sci 2009; 1(1): 17-23. [ Links ]
12. Vázquez L, Rodríguez P, Moreno F. Análisis macroscópico in vitro de los tejidos dentales y de algunos materiales dentales de uso en endodoncia, sometidos a altas temperaturas con fines forenses. Rev Odont Mex 2010 (en prensa). [ Links ]
13. Colombia. Ministerio de la Protección Social. Resolución N.° 008430/1993 de octubre 4. Por la cual se establecen las normas científicas, técnicas y administrativas para la investigación en salud [fecha de acceso febrero de 2009] URL disponible en http://www.minproteccionsocial.gov.co/vbecontent/library/documents/DocNewsNo267711.pdf [ Links ]
14. Asociación Médica Mundial. Principios éticos para las investigaciones médicas en seres humanos. Declaración de Helsinki. Finlandia, junio de 1964 [fecha acceso febrero de 2009] URL disponible en http://www.wma.net/s/policy/b3.htm [ Links ]
15. Instituto Colombiano de Normas Técnicas. Materiales odontológicos: Ensayo de la adhesión a la estructura dental. Bogotá: Icontec 4882; 2000. [ Links ]
16. International Organization of Standardization. Dental materials: Testing of adhesion to tooth structure. ISO/TS 11405: 2003. [ Links ]
17. Cohen S, Burns RC. Pathways of the pulp. 8.ª ed. St. Louis: Mosby; 2002. [ Links ]
18. Delattre VF. Burned beyond recognition: Systematic approach to the dental identification of charred human remains. J Forensic Sci 2000; 45: 589-596. [ Links ]
19. Moya V, Roldán B, Sánchez JA. Odontología legal y forense. Barcelona: Masson; 1994. [ Links ]
20. Norrlander AL. Burned and incinerated remains. En: Bowers CM, Bell GL, Eds. Manual of forensic odontology. 3.ª ed. Colorado Springs: American Society of Forensic Odontology; 1997. p. 16-18. [ Links ]
21. Bohnert M, Rost T, Pollak S. The degree of destruction of human bodies relation to the duration of the fire. Forensic Sci Int 1998; 95:11-21. [ Links ]
22. Delattre VF. Burned beyond recognition: Systematic approach to the dental identification of charred human remains. J Forensic Sci 2000; 45: 589-596. [ Links ]
23. Torneck CD. El complejo pulpodentinario. En: Ten Cate AR, ed. Histología oral: desarrollo, estructura y función. 2.ª ed. Buenos Aires: Editorial Médica Panamericana; 1986. p. 190-235. [ Links ]
24. Eisenmann DR. Estructura del esmalte. En: Ten Cate AR, Editor Histología oral: desarrollo, estructura y función. 2.a ed. Buenos Aires: Editorial Médica Panamericana; 1986. p. 252-273. [ Links ]
25. Rötzscher K, Grundmann C, Benthaus S. The effects of high temperatures on human teeth and dentures. Int Poster J Dent Oral Med 2004; 6: Póster 213. [ Links ]
26. Patidar KA, Parwani R, Wanjari S. Effects of high temperature of different restorations in forensic identification: dental samples and mandible. J Forensic Dent Sci 2010; 2(1): 37-43. [ Links ]
27. López L, Arimany J, Prieto L, Martínez M. Importancia de la endodoncia en la identificación de cadáveres carbonizados. A propósito de un caso. Tercera Jornada Catalana de Actualización en Medicina Forense. España. Barcelona: Departamento de Justicia de Cataluña; 1995. p. 215-223. [ Links ]
28. Friedman CE, Sandrik JL, Heuer MA, Rapp GW. Composition and physical properties of gutta-percha endodontic filling materials. J Endod 1977; 3: 304-308. [ Links ]
29. Bonavilla JD, Bush MA, Bush PJ, Pantera EA. Identification of incinerated root canal filling materials after exposure to high heat incineration. Forensic Sci 2008; 53(2): 412-408. [ Links ]
