Development of a new in vitro methodology to simulate internal root resorption.
BACKGROUND
Studies to evaluate the diagnostic power of imaging examinations to detect root resorption have been based on simulations produced by burs. Standardized, round, and well-outlined access cavities do not reproduce the characteristics of physiological lesions and may facilitate diagnosis, masking the true accuracy of imaging techniques. A methodology to simulate internal root resorption by using acid demineralization was developed.


METHODS
Eleven extracted single-rooted teeth were mesiodistally sectioned into homologous halves. Root canals were labeled to ensure restricted and controlled action of fluids. The protocol was composed of 24-hour cycles (5% nitric acid for 12 hours, rinsing with deionized water, and 8% sodium hypochlorite for 10 minutes). At the end of each cycle 1 tooth was removed from treatment, defining an exposure time that cumulated to the last tooth. Electron microscopy imaging was assessed to determine lesion area and depth.


RESULTS
Minimum and maximum and areas and depths were 3.14 mm² and 10.34 mm² and 0.22 mm and 1.59 mm, respectively. Resorption simulated by the protocol proposed reproduced lesions of different sizes.


CONCLUSIONS
The irregular shape and larger diameter:depth ratio suggest that these lesions are more similar to in vivo internal root resorption, compared with bur-induced lesions.
Oral Radiology Division, Department of Surgery and Orthopedics, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil. Electronic address: prifsilveira@yahoo.com.br.
Priscila Fernanda
PF
da Silveira
Oral Radiology Division, Department of Surgery and Orthopedics, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
Mariana Boessio
MB
Vizzotto
Endodontic Division, Department of Conservative Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
Francisco
F
Montagner
Oral Radiology Division, Department of Surgery and Orthopedics, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
Heraldo Luis Dias
HL
da Silveira
Oral Radiology Division, Department of Surgery and Orthopedics, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
Heloísa Emília Dias
HE
da Silveira
D054893:Cone-Beam Computed Tomography / Q000379:methods; D003481:Cuspid / Q000000981:diagnostic imaging / Q000187:drug effects / Q000473:pathology; D003804:Dentin / Q000000981:diagnostic imaging / Q000187:drug effects / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D066298:In Vitro Techniques; D007180:Incisor / Q000000981:diagnostic imaging / Q000187:drug effects / Q000473:pathology; D008855:Microscopy, Electron, Scanning; D017942:Nitric Acid / Q000009:adverse effects; D009811:Odontometry / Q000379:methods; D012391:Root Resorption / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology; D012973:Sodium Hypochlorite / Q000009:adverse effects; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods
D017942:Nitric Acid; D012973:Sodium Hypochlorite
Internal root resorption; methodology; scanning electron microscopy