Objective: The purpose of this study was to evaluate the influence of the magnification factor of the radiographic image in angular, linear and proportional measurements. Methods: From a dried human skull where metallic spheres with predetermined size were fixed (1.0 mm), 14 radiographs were obtained in devices of three different manufacturers: Panoura, Instrumentarium and Tomeceph. The Pearson correlation test was used to investigate the relationship between the rate of radiographic magnification and the cephalometric measurements assessed. Results: According to the results, the linear measurements showed a high positive correlation, pointing out great influence of the magnification factor, while the angular and proportional measurements did not correlate. Conclusions: Comparisons between linear cephalometric measurements obtained with different devices from the same manufacturer showed maximum rates of expansion of 0.6%, 1.25% and 2.3%, respectively, for the devices from Instrumentarium (OP-100, Instrumentarium, Finland), Panoura (10CSU, Yoshida, Japan) and Satelec/Tomeceph (XMind, Satelec/Tomeceph Orion Corporation, Finland). Keywords:Orthodontics. Diagnostic. Radiograph. Radiographic magnification.Objetivo: avaliar a influência do fator de magnificação da imagem radiográfica nas grandezas angulares, lineares e proporcionais.Métodos: a partir de um crânio seco humano, no qual foram fixadas esferas metálicas de dimensões pré-definidas (1,0mm de diâmetro), 14 telerradiografias foram obtidas em diferentes aparelhos de três fabricantes: Panoura, Instrumentarium e Tomeceph.Foi realizada a análise estatística descritiva e utilizado o teste de correlação de Pearson para verificar a relação entre a taxa de magnificação radiográfica e as grandezas cefalométricas analisadas. Resultados: as medidas lineares apresentaram alta correlação positiva, evidenciando grande influência do fator de magnificação sobre essas grandezas, ao passo que as angulares e proporcionais não apresentaram correlação. Conclusão: comparações entre medidas cefalométricas lineares obtidas com diferentes aparelhos do mesmo fabricante demonstraram taxas de ampliações máximas de 0,6%, 1,25% e 2,3%, respectivamente, para os aparelhos Instrumentium (OP-100 Instrumentarium), Panoura (10CSU Yoshida) e Satelec/Tomeceph (XMind Satelec/Tomeceph Orion Corp).Palavras-chave: Ortodontia. Diagnóstico. Radiografia. Ampliação radiográfica.
Facial harmony is one of the main goals of orthodontic treatment, and it is not always correlated with the attainment of cephalometric objectives. The purpose of this study was to evaluate two groups of subjects presenting a clinically balanced soft tissue profile using cephalometric radiographs. Thirty lateral cephalometric radiographs of white females, divided in two groups, one with excellent facial profile (Group 1), and the other with good facial profile (Group 2) were used. Student's t-test (P < .05) was used to compare the cephalometric parameters of the 2 groups. Linear regression analysis was also performed between 1.NB and SnV-Pog and between AB horizontal and SnV-Pog'. Group 2 showed higher mean values than group 1 for ANB (p = 0.002), AB horizontal (p < 0.001), 1.NB (p < 0.001), and a lower mean value for SnV-Pog (p = 0.003). The higher the SnV-Pog value, the lower the 1.NB value, no matter what group was evaluated. For each 1 mm increase in SnV-Pog, a 0.61 degree decrease could be expected in 1.NB (p = 0.003). The higher the SnV-Pog value, the lower the AB horizontal value, although group 2 presented greater AB horizontal values. For each 1 mm increase in SnV-Pog, a 0.24 mm decrease could be expected in AB horizontal (p = 0.019). We concluded that women with good facial profile do not necessarily present the same cephalometric values, and facial analysis should be the main reference in planning orthodontic treatments and should be considered together with cephalometric analysis in an individualized way.
The purpose of this study was to radiographically evaluate subjects with balanced facial profile, using an extracranial reference line. Twenty-five cephalometric radiographs of white male brazilians, with ages between 18 and 33 years, obtained in the oriented natural head position were used. Cephalometric analysis was used to evaluate the nasal projection, lips and the soft pogonion in relation to a vertical line that passes by the subnasal point (SnV), the maxilla and the mandible in relation to the cranial base and the incisors in relation to their bone bases. All variables were submitted to the Kolmogorov-Smirnov (P<0,05) and the Shapiro-Wilk (P<0,05) test and it was verified that the sample had a normal distribution. The method error was assessed with intraclass correlation and Dalhberg's formula, showing small errors between measurements. Mean, standard deviation, median, minimum and maximum values were calculated. It was verified that the mean projection of the nose was 17.94 mm forward the subnasal vertical line (SnV), the upper lip was in front of he SnV line by 2.20 mm, the lower lip was behind the SnV line by-0.24 mm and the soft tissue pogonion was behind the SnV line by-5.95 mm. The mean values of the maxilla and the mandible in relation to the cranial base were 84.80 0 and 82.82 0 respectively. The mean values of upper and lower incisors axial inclinations were 25.87 0 and 27.22 0 respectively. Correlation among the variables was assessed using Pearson's correlation coefficient (P<0.05). The main statistically significant positive correlations were observed between the mandibular plane angle and the distance between upper and lower lip (p=0.048), the upper and lower lip projection (p<0.001), the lower lip projection and soft tissue pogonion (p=0.005). The main statistically significant negative correlations were observed between the maxillary projection and the pogonion projection (p=0.044), between lower lip projection and the distance between upper and lower lip (p=0,002), and between the distance between upper and lower lip and soft tissue pogonion projection (p=0.001).
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