RESUMEN
OBJECTIVES: Two-dimensional intraoral radiography is the most common tool for diagnosing root fractures (RFs). Cone beam CT (CBCT) is widely used to depict RFs in endodontically treated teeth. Beam hardening and other artefacts caused by gutta percha may result in an incorrect diagnosis when using CBCT only. A comparison of two CBCT machines with photostimulated phosphor (PSP) plate images enhanced with the equalization tool was carried out to detect RFs in endodontically treated teeth. METHODS: 66 roots were collected, decoronated and treated endodontically using the same technique with gutta percha. 33 of these roots were randomly selected and fractured; the 2 root fragments were glued together with 1 layer of methyl methacrylate and placed randomly in 8 prepared beef rib fragments. Large fields of view (FOVs) were acquired with one CBCT unit and small FOVs with the second CBCT unit. Periapical radiographs (using intraoral PSP plates) were also acquired. A contrast enhancement tool was used when evaluating the PSP plate images. RESULTS: Small FOV images had significantly higher accuracy (area under the receiver operating characteristic curve) and sensitivity in detecting RFs than PSP plates and large FOV images. The specificity of the enhanced PSP images was higher than, although not significantly higher than, the small FOV images and was significantly higher than the large FOV images. CONCLUSIONS: CBCT small FOVs should be acquired for depicting RFs of endodontically treated teeth. Images obtained using PSP plates had the lowest rate of false-positive results and their use can save the patient a radiation dose.
Asunto(s)
Tomografía Computarizada de Haz Cónico/métodos , Radiografía de Mordida Lateral/instrumentación , Fracturas de los Dientes/diagnóstico por imagen , Raíz del Diente/lesiones , Diente no Vital/diagnóstico por imagen , Pantallas Intensificadoras de Rayos X , Área Bajo la Curva , Tomografía Computarizada de Haz Cónico/estadística & datos numéricos , Cavidad Pulpar/diagnóstico por imagen , Reacciones Falso Positivas , Gutapercha/uso terapéutico , Humanos , Variaciones Dependientes del Observador , Curva ROC , Dosis de Radiación , Intensificación de Imagen Radiográfica/instrumentación , Radiografía de Mordida Lateral/estadística & datos numéricos , Radiografía Dental Digital/métodos , Radiografía Dental Digital/estadística & datos numéricos , Materiales de Obturación del Conducto Radicular/uso terapéutico , Sensibilidad y Especificidad , Factores de TiempoRESUMEN
The purpose of this report is to present a mathematical model relating changes in grey values to changes of thicknesses of a stepwedge. Radiographs of a stepwedge were obtained through a limited exposure range on a single Kodak 6100 charge-coupled device detector at 63 kVp and 70 kVp. Grey values from each step were evaluated relative to the corresponding step thickness. All possible regression fits were evaluated based on their coefficient of determination (R(2)) value and their mean squared errors (MSEs) relative to the original thickness. For all exposure settings, the fifth-degree polynomial was the best possible fit, with the highest R(2) value and the lowest MSE.
