Comparison of changes in dental and bone radiographic densities in the presence of different soft-tissue simulators using pixel intensity and digital subtraction analyses.

OBJECTIVES: To evaluate the influence of soft-tissue simulation materials on dental and bone tissue radiographic densities using pixel intensity (PI) and digital subtraction radiography (DSR) analyses. METHODS: 15 dry human mandibles were divided into halves. Each half was radiographed using a charge-coupled device sensor without a soft-tissue simulation material (Wm) and with 5 types of materials: acrylic (Ac), wax (Wx), water (Wt), wood (Wd) and frozen bovine tissue (Bt). Three thicknesses were tested for each material: 10 mm, 15 mm and 20 mm. The material was positioned in front of the mandible and the sensor parallel to the molar region. The radiation beam was perpendicular to the sensor at 30 cm focal spot-to-object distance. The digital images of the bone and dental tissue were captured for PI analyses. The subtracted images were marked with 14 landmark magnifications, and 2 areas of analyses were defined, forming the regions of interest. Shapiro-Wilk and Kruskal-Wallis tests followed by Dunn's post-test were used (p < 0.05). RESULTS: DSR showed that both the material type and the thickness tested influenced the gain of density in bone tissue (p < 0.05). PI analyses of the bone region did not show these differences, except for the lower density observed in the image without soft-tissue simulation material. In the dental region, both DSR and PI showed that soft-tissue simulators did not influence the density in these regions. CONCLUSIONS: This study showed that the materials evaluated and their thicknesses significantly influenced the density-level gain in alveolar bone. In dental tissues, there was no density-level gain with any soft-tissue material tested.

Detection of cavitated approximal surfaces using cone beam CT and intraoral receptors.

OBJECTIVES: The aim of this study was to compare cone beam CT (CBCT) in a small field of view (FOV) with a solid-state sensor and a photostimulable phosphor plate system for detection of cavitated approximal surfaces. METHODS: 257 non-filled approximal surfaces from human permanent premolars and molars were recorded by two intraoral digital receptors, a storage phosphor plate (Digora Optime, Soredex) and a solid-state CMOS sensor (Digora Toto, Soredex), and scanned in a cone beam CT unit (3D Accuitomo FPD80, Morita) with a FOV of 4 cm and a voxel size of 0.08 mm. Image sections were carried out in the axial and mesiodistal tooth planes. Six observers recorded surface cavitation in all images. Validation of the true absence or presence of surface cavitation was performed by inspecting the surfaces under strong light with the naked eye. Differences in sensitivity, specificity and agreement were estimated by analysing the binary data in a generalized linear model using an identity link function. RESULTS: A significantly higher sensitivity was obtained by all observers with CBCT (p < 0.001), which was not compromised by a lower specificity. Therefore, a significantly higher overall agreement was obtained with CBCT (p < 0.001). There were no significant differences between the Digora Optime phosphor plate system and the Digora Toto CMOS sensor for any parameter. CONCLUSIONS: CBCT was much more accurate in the detection of surface cavitation in approximal surfaces than intraoral receptors. The differences are interpreted as clinically significant. A CBCT examination performed for other reasons should also be assessed for approximal surface cavities in teeth without restorations.

Comparison of simulated periodontal bone defect depth measured in digital radiographs in dedicated and non-dedicated software systems.

OBJECTIVES: To compare simulated periodontal bone defect depth measured in digital radiographs with dedicated and non-dedicated software systems and to compare the depth measurements from each program with the measurements in dry mandibles. METHODS: Forty periodontal bone defects were created at the proximal area of the first premolar in dry pig mandibles. Measurements of the defects were performed with a periodontal probe in the dry mandible. Periapical digital radiographs of the defects were recorded using the Schick sensor in a standardized exposure setting. All images were read using a Schick dedicated software system (CDR DICOM for Windows v.3.5), and three commonly available non-dedicated software systems (Vix Win 2000 v.1.2; Adobe Photoshop 7.0 and Image Tool 3.0). The defects were measured three times in each image and a consensus was reached among three examiners using the four software systems. The difference between the radiographic measurements was analysed using analysis of variance (ANOVA) and by comparing the measurements from each software system with the dry mandibles measurements using Student's t-test. RESULTS: The mean values of the bone defects measured in the radiographs were 5.07 mm, 5.06 mm, 5.01 mm and 5.11 mm for CDR Digital Image and Communication in Medicine (DICOM) for Windows, Vix Win, Adobe Photoshop, and Image Tool, respectively, and 6.67 mm for the dry mandible. The means of the measurements performed in the four software systems were not significantly different, ANOVA (P = 0.958). A significant underestimation of defect depth was obtained when we compared the mean depths from each software system with the dry mandible measurements (t-test; P approximately equal to 0.000). CONCLUSIONS: The periodontal bone defect measurements in dedicated and in three non-dedicated software systems were not significantly different, but they all underestimated the measurements when compared with the measurements obtained in the dry mandibles.

Accuracy of zoomed digital image in the detection of periodontal bone defect: in vitro study.

OBJECTIVES: (1) To evaluate the intraobserver agreement related to image interpretation and (2) to compare the accuracy of 100%, 200% and 400% zoomed digital images in the detection of simulated periodontal bone defects. METHODS: Periodontal bone defects were created in 60 pig hemi-mandibles with slow-speed burs 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm and 3.0 mm in diameter. 180 standardized digital radiographs were made using Schick sensor and evaluated at 100%, 200% and 400% zooming. The intraobserver agreement was estimated by Kappa statistic (kappa). For the evaluation of diagnostic accuracy receiver operating characteristic (ROC) analysis was performed followed by chi-square test to compare the areas under ROC curves according to each level of zooming. RESULTS: For 100%, 200% and 400% zooming the intraobserver agreement was moderate (kappa=0.48, kappa=0.54 and kappa=0.43, respectively) and there were similar performances in the discrimination capacity, with ROC areas of 0.8611 (95% CI: 0.7660-0.9562), 0.8600 (95% CI: 0.7659-0.9540), and 0.8368 (95% CI: 0.7346-0.9390), respectively, with no statistical significant differences (chi2-test; P=0.8440). CONCLUSIONS: A moderate intraobserver agreement was observed in the classification of periodontal bone defects and the 100%, 200% and 400% zoomed digital images presented similar performances in the detection of periodontal bone defects.

A survey of radiographic prescription in dental implant assessment.

OBJECTIVES: To survey the current radiographic prescriptions in dental implant assessment amongst dentists in Brazil. METHODS: Sixty-nine dentists were interviewed during a dental implant meeting by two calibrated graduate students, using a 19-question questionnaire, considering imaging modality options both for pre-operative implant site assessment and for follow-up, particularly with respect to cost, patient radiation dose, and broad coverage of facial bones and teeth. Epi-Info 6.04 software was used to analyse the database file. RESULTS: Approximately 63.8% of the dentists prescribed only panoramic radiography for dental implant assessment and 28.9% ordered panoramic radiography plus periapical radiography and/or conventional tomography and/or computed tomography (CT). Only 7.2% of the dentists ordered conventional tomography or CT as a single examination, although 10.1% ordered it in combination with other imaging modalities. The main reasons given for prescribing panoramic radiography were broad coverage and cost (86.4%). CONCLUSIONS: This study has shown that most of the dentists in this study prescribe panoramic radiographs in dental implant assessment based on broad coverage and cost. They are not following the American Academy of Oral and Maxillofacial Radiology recommendations regarding cross-sectional imaging.

Dosimetry and cost of imaging osseointegrated implants with film-based and computed tomography.

Thermoluminescent dosimeters were used to measure radiation doses at craniofacial sites in a tissue-equivalent phantom during film-based multidirectional tomography with the Tomax Ultrascan (Incubation Industries, Ivyland, Pa.) and during computed tomography with the Elscint Excel 2400 (Elscint Corp., Tel Aviv, Israel). Mean absorbed doses for presurgical mandibular and maxillary canine and molar implant assessments were converted to equivalent doses, which were then multiplied by published weighting factors and summed to give effective doses. The computed tomography device consistently delivered higher doses than the Tomax Ultrascan to all anatomic locations; the differences were most pronounced when only one or two implant sites were evaluated. The reasons for the dose disparities are considered both anatomically and procedurally. A survey of examination cost revealed film-based multidirectional tomography to be less expensive than computed tomography.

Niobium filtration of conventional and high-frequency x-ray generator beams for intraoral radiography. Effects on absorbed doses, image density and contrast, and photon spectra.

We have studied the effects of niobium beam filtration on absorbed doses, on image density and contrast, and on photon spectra with conventional and high-frequency dental x-ray generators. Added niobium reduced entry and superficial absorbed doses in periapical radiography by 9% to 40% with film and digital image receptors, decreased the radiation necessary to produce a given image density on E-speed film and reduced image contrast on D- and E-speed films. As shown by increased half-value layers for aluminum, titanium, and copper and by pulse-height analyses of beam spectra, niobium increased average beam energy by 6% to 19%. Despite the benefits of adding niobium on patient dose reduction and on narrowing the beams' energy spectra, the beam can be overhardened. Adding niobium, therefore, strikes the best balance between radiation dose reduction and beam attenuation, with its risks of increased exposure times, motion blur, and diminished image contrast, when it is used at modest thicknesses (30 microns) and at lower kVp (70) settings.

Assessment of the nasopharyngeal area by cephalometry in cases of cleft lip and palate.

The nasopharyngeal area in 149 patients with cleft lip and palate and 157 normal individuals was evaluated by cephalometric radiography. The patients were male and female Caucasians, ranging in age from 12 to 16 years. Linear cephalometric parameters: (Ptm'-Sl; Ptm'-IPPF; IPPF-I, I-Ptm'), ANS angle and nasopharyngeal area were utilized. From comparative analysis of nasopharyngeal area in the cleft and the control groups, the following conclusions were made: 1) The nasopharyngeal area was smaller in the cleft group. 2) There was no correlation between ANS angle and nasopharyngeal area in either group.

[Analysis of the nasal area in unilateral cleft lip and palate, by means of cephalometric teleradiography]. / Análisis del área nasal en fisurados transforamen incisivo unilateral, a través de telerradiografías cefalométricas.

In a cross-sectional study with 149 patients with complete unilateral cleft lip and palate and 157 non-cleft patients aged from twelve to sixteen, Caucasian males and females were evaluated through lateral cephalometric radiographs of the nasal area. One angular (SNA), 4 linear (S-N; N-P'; P'-Ptm'; Ptm'S) and medial cephalometric measurements of the nasal area were used. In a comparative analysis of the nasal area in cleft lip and palate and control groups one can conclude that: 1. The nasal area in cleft patients is smaller than in non-cleft patients. 2. There is no correlation between the angle (SNA) and the nasal area for the cleft patients and control patients.

Determinacao da idade da menarca em meninas brancas, brasileiras, da regiao de Bauru. / Mean age of menarche in Brazilian white girls from Bauru

Hum mil trezentas e setenta e nove meninas da regiao de Bauru, com idades variando entre 8 a 16 anos, foram interrogadas com vistas a se estimar as idades da pubescencia e da menarca pelo metodo retrospectivo. Os resultados encontrados foram de 10,42 +/- 1.10 anos para a idade media da pubescencia e 12,97 +/- 1,23 anos para a menarca

Comparacao entre dois metodos para estimar as idades de pubescencia e menarca. / Comparison between two methods for estimation of mean age at pubescence and menarche

Os autores estudaram 1.379 meninas brancas brasileiras, da regiao de Bauru, com o objetivo de estimar e comparar as idades da pubescencia e da menarca atraves de dois diferentes metodos: retrospectivo e de Frisancho el al. Os resultados obtidos mostraram nao haver diferenca significante entre os valores auferidos. Optaram pela maior aplicabilidade do metodo de Frisancho el al. por depender apenas de uma radiografia da mao e carpo, eliminando portanto, a subjeticidade envolvida com o metodo retrospectivo. Alem dessa vantagem ressaltaram o aspecto do referido metodo ser aplicavel a pequenas amostras

Comportamento das idades estatural, ponderal, ossea e dentaria, antes e durante a puberdade, em meninas brancas, brasileiras, da regiao de Bauru. / The behaviour of height, weight, osseous and dental ages, before and during puberty in Brazilian white girls from Bauru

Idades estatural, ponderal, ossea e dentaria de 734 meninas brancas, brasileiras, da regiao de Bauru, Estado de Sao Paulo, foram estimados com o objetivo de verificar o comportamento desses indices durante a puberdade. A amostra, cujas faixas etarias variaram de seis aos 16 anos, foi separada em individuos puberes e impuberes pela ocorrencia da menarca atraves do metodo retrospectivo. A idade ossea foi a que melhor discriminou as aceleracoes ou atrasos da puberdade. A idade dentaria acompanhou a idade cronologica. O estirao de crescimento em altura e peso teve seu maximo incremento aos 12 anos. As altas correlacoes dos varios indices entre si e com a idade cronologica encontradas na amostra global, sofreram significantes decrescimos nas faixas etarias mais envolvidas na puberdade. Ficou estabelecido que as tabelas de crescimento devem conter valores separados para individuos puberes e impuberes