title: Pixel value analysis for detection of simulated early external root resorption.
abstract: The aim of this study was to determine the efficacy of pixel value analysis using images generated by the Digora™ and Visualix™ systems for the early detection of external root resorption (ERR). Thirty extracted human lower incisors were radiographed using the Digora and Visualix systems; then, ERR was induced by immersing the teeth in 6 mol L-1 of hydrochloric acid for different periods of time (10, 30 and 60 minutes). ERR was confirmed by calcium quantification with an atomic absorption spectrophotometer. One digital image was acquired per time period at 70 kVp, 7 mA, 2.2 mm filtration, focus-film distance of 30 cm, and with exposure times of 0.09 s in the Digora system and 0.05 s in Visualix system. The region of interest was defined using ImageJ software. Statistical analysis was performed using ANOVA and Pearson's correlation (p < 0.05). There was no statistically significant difference between the time for ERR induction and the pixel values with either system. A positive correlation between the time of ERR induction and the calcium concentration was observed (r = 0.8892; p < 0.001). In conclusion, independent of the site of ERR induction and the digital system, pixel value analysis was not effective for ERR detection.
authors.affiliation: Department of Oral Radiology, Faculty of Dentistry, Universidade Norte do Paraná, Londrina, PR, Brazil.
authors.forename: Marcelo Lupion
authors.initials: ML
authors.lastname: Poleti
authors.affiliation: Department of Orthodontics, Faculty of Dentistry,, Universidade Norte do Paraná, Londrina, PR, Brazil.
authors.forename: Thais Maria Freire
authors.initials: TM
authors.lastname: Fernandes
authors.affiliation: Private practice, Santa Rita do Passa Quatro, SP, Brazil.
authors.forename: Camila Cristina
authors.initials: CC
authors.lastname: Paiz
authors.affiliation: Department of Stomatology, Bauru School of Dentistry, Universidade de São Paulo, Bauru, SP, Brazil.
authors.forename: Izabel Regina Fischer
authors.initials: IR
authors.lastname: Rubira-Bullen
authors.affiliation: Department of Stomatology, Bauru School of Dentistry, Universidade de São Paulo, Bauru, SP, Brazil.
authors.forename: Ana Lúcia Alvares
authors.initials: AL
authors.lastname: Capelozza
mesh_terms: D000704:Analysis of Variance; D042241:Early Diagnosis; D006801:Humans; D007180:Incisor / Q000000981:diagnostic imaging; D019252:Radiography, Dental, Digital / Q000295:instrumentation* / Q000379:methods*; D012016:Reference Values; D015203:Reproducibility of Results; D012391:Root Resorption / Q000000981:diagnostic imaging*; D013054:Spectrophotometry, Atomic; D013997:Time Factors