Influence of scan mode (180°/360°) of the cone beam computed tomography for preoperative dental implant measurements.

OBJECTIVE: The aim of this study was to evaluate the effect of scan mode of the cone beam computed tomography (CBCT) in the preoperative dental implant measurements. MATERIAL AND METHODS: Completely edentulous mandibles with entirely resorbed alveolar processes were selected for this study. Five regions were selected (incisor, canine, premolar, first molar, and second molar). The mandibles were scanned with Next Generation i-CAT CBCT unit (Imaging Sciences International, Inc, Hatfield, PA, USA) with half (180°) and full (360°) mode. Two oral radiologists performed vertical measurements in all selected regions; the measurements of half of the sample were repeated within an interval of 30 days. The mandibles were sectioned using an electrical saw in all evaluated regions to obtain the gold standard. The intraclass correlation coefficient was calculated for the intra- and interobserver agreement. Descriptive statistics were calculated as mean, median, and standard deviation. Wilcoxon signed rank test was used to determine the correlation between the measurements obtained in different scan mode with the gold standard. The significance level was 5%. RESULTS: The values of intra- and interobserver reproducibility indicated a strong agreement. In the dental implant measurements, except the bone height of the second molar region in full scan mode (P = 0.02), the Wilcoxon signed rank test did not show statistical significant difference with the gold standard (P > 0.05). CONCLUSIONS: Both modes provided real measures, necessary when performing implant planning; however, half scan mode uses smaller doses, following the principle of effectiveness. We believe that this method should be used because of the best dose-effect relationship and offer less risk to the patient.

Magnitude of cone beam CT image artifacts related to zirconium and titanium implants: impact on image quality.

OBJECTIVES: To evaluate the magnitude of artifacts related to titanium and zirconium implants at different distances and angulations and their impact on cone beam CT(CBCT) image quality. METHODS: CBCT images were obtained before and after the insertion of titanium and zirconium implants in a mandible on different CBCT units: Picasso Trio, ProMax 3D and 3D Accuitomo 80. Artifact was assessed by measuring the standard deviation (SD) of gray values and contrast-to-noise ratio (CNR) of 11 regions of interest (ROIs) at different distances (1.5 cm, 2.5 cm and 3.5 cm) and angulations (65°, 90°, 115° and 140°) from implant region. RESULTS: For titanium images, SD values did not differ from those of images without implant in all ROIs; however, some effect occurred in Picasso images as higher values were observed in ROIs closer to the implant (p < 0.05). Zirconium images showed higher SD values than the others in some ROIs for Picasso and ProMax (p < 0.05). In ProMax, the difference was observed even in the farthest ROIs from the implant. CNR values were not influenced by the ROI in Picasso, but presented lower values in ROIs closer to the zirconium implant for ProMax and Accuitomo. CONCLUSIONS: The quantity and magnitude of artifacts in CBCT are influenced by the type of implant and CBCT unit. Although they are more pronounced in regions closer to the implant and located at 90° in relation to the mandibular long axis, they can reach as far as 3.5 cm from the artifact-generator object.

Atitudes dos cirurgiões-dentistas em relação à proteção radiológica, de acordo com a lei brasileira / Attitudes of dentists in relation to radiological protection, according to brazilian law

Objetivo: Realizar uma pesquisa em consultórios odontológicos na cidade de São José do Rio Preto - SP sobre conhecimento e atitudes dos profissionais sobre proteção radiológica e comparar os dados com as recomendações da Portaria 453 do Ministério da Saúde. Material e Método: Cento e cinqüenta consultórios odontológicos foram visitados e foi aplicado um questionário. Resultados: Observou-se que 26% dos entrevistados não conheciam a lei, 23% não avaliavam radiografias existentes do paciente, 21% não usavam vestimenta plumbífera nos pacientes, 49% não usavam posicionadores de filmes, 58% ainda utilizavam processamento visual; 93% utilizavam filme E ou F, entretanto a média de tempo de exposição foi 0.5 segundo, 14% dos equipamentos possuíam cone localizador e 83% seletor de tempo manual, 17% dos dentistas não se protegiam durante a exposição do paciente e 64% ainda utilizavam disparador com retardo. Conclusão: Há falta de conhecimento sobre proteção radiológica; um programa educacional em Radiologia pode produzir mudanças nas atitudes dos profissionais em relação ao uso da radiação ionizante.

Objective: To perform a research in dental offices in the city of São José do Rio Preto-SP about the practitioners' knowledge and attitudes related to radiological protection and compare the data with the recommendations of Ordinance 453 of the Health Ministry. Material and Methods: One hundred and fifty dental offices were visited and a questionnaire was applied. Results: Was observed that 26% of the interviewed did not know the law, 23% did not evaluate the patient's existing radiographs, 21% did not wear lead clothing in patients, 49% did not use film positioners, 58% still used visual processing, 93% used film E or F, however the average exposure time was 0.5 second, 14% of the equipment had locator cone and 83% had manual time selector, 17% of dentists do not protect themselves during the patient's exposure and 64% still used delayed trigger. Conclusion: There Atitudes dos Cirurgiões-Dentistas em Relação à Proteção Radiológica, de Acordo com a Lei Brasileira Pesquisa Rev Odontol Bras Central 2010;19(51) 305 is a lack of knowledge about radiological protection. An educational program in Radiology can produce changes in attitudes of professionals regarding the use of ionizing radiation.