Analysis of refractive parameters and theirs correlation with spherical equivalent in preschool children aged 3 to 6 years / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To investigate the distribution of refractive parameters and theirs correlation with spherical equivalent(SE)in preschool children aged 3 to 6 years, and evaluate the accuracy of each screening index in diagnosing refractive errors.METHODS: Cross-sectional study. A total of 791 preschool children, ranging from 3 to 6 years old, who consented to undergo mydriatic refraction were selected. Axial length(AL), corneal refractive power(K), and SE were measured after microcoria optometry and mydriatic optometry. Additionally, the corneal radius of curvature(CR)and the axial length/corneal radius of curvature(AL/CR)ratio were calculated.RESULTS: A total of 791 students participated in the study, out of which 400(50.6%)were male and 391(49.4%)were female. The mean values for AL, CR, AL/CR, and SE were 22.62±0.94mm, 7.81±0.29mm, 2.90±0.09, and +1.95±1.31D, respectively. AL, CR, and AL/CR increased with age. AL and CR were significantly higher in males than in females(all P<0.001), while there was no statistically significant difference between AL/CR and SE in males and females(P=0.82, 0.19). The correlation coefficients of SE and AL/CR, AL and CR were -0.86, -0.50 and 0.16, respectively. The results of multiple linear regression analysis indicate that for each unit increase in AL/CR, there was a corresponding shift of 10.91 towards myopia in SE. The sensitivity of AL/CR in screening for myopia was 94.44%, with a specificity of 90.46% and a Youden index of 0.84. For screening myopia under microcoria optometry, the sensitivity was 100%, with a specificity of 66.09% and a Youden index of 0.66. The area under the curve was 0.967 and 0.809 when the ROC curves were plotted using AL/CR and AL as indicators for screening myopia, respectively.CONCLUSION: For large group screening activities where mydriatic optometry is not feasible, AL/CR is better for evaluating refractive status and identifying children with myopia and hyperopia reserve that are lower than normal for their age, compared to AL and microcoria optometry.

Comparación entre los sistemas manual de limas de acero inoxidable y el rotatorio de limas de níquel titanio, en la conformación de conductos radiculares curvos in vitro / Comparison between the manual system of stainless steel files and the rotating system of nickel titanium files in the conformation of curved radicular ducts in vitro

Resumen Introducción: Estudio experimental donde se procuró comparar el efecto del sistema manual y del rotatorio sobre la conformación de conductos curvos. Metodología: Una muestra de 40 raíces mesiales de primeras molares inferiores fue aleatorizada en dos grupos iguales: grupos sistema manual de limas K y sistema rotatorio FGK Race®. Se comparó el radio de la curvatura final vs. el inicial mediante el programa Autocat 2015. Se empleó la prueba t con significancia de 0,05. Resultados: El radio de la curvatura varió de manera significativa, tanto para sistema manual como para el rotatorio FGK Race® (p=0,0001 y p=0,0013, respectivamente). Además, el sistema manual produjo mayor variación en el radio de la curvatura al compararlo con el sistema rotatorio 2,23 mm vs. 1,27 mm respectivamente; p=0,13. Conclusiones: Ambos sistemas produjeron modificación en la conformación de los conductos mesiales; sin embargo, en la comparación entre ambos dichas diferencias no fueron significativas.

Abstract Introduction: An experimental study was carried out to compare the effect of the manual system and the rotary system on the conformation of curved conduits. Methodology: A sample of 40 mesial roots of lower first molars was randomized into two equal groups: group manual system of K-files and group rotary system FGK Race®. The radius of the final curvature vs. the initial curvature was compared using the Autocat 2015 program. The t-test with a significance of 0.05 was used. Results: The curvature radius varied significantly for both the manual system and the rotary FGK Race® (p = 0.0001 and p = 0.0013, respectively). In addition, the manual system produced greater variation in the radius of the curvature when compared to the rotary system 2.23mm vs. 1.27mm respectively; p = 0.13. Conclusion: Both systems produced modification on the conformation of the conduits of the mesial roots; however, in the comparison between both systems said differences were not significant.

An evaluation of canal curvature at the apical one third in type II mesial canals of mandibular molars

OBJECTIVES: The purpose of this study was to evaluate the buccolingual curvature at the apical one third in type II mesial canals of mandibular molars using the radius and angle of curvature. MATERIALS AND METHODS: Total 100 mandibular molars were selected. Following an endodontic access in the teeth, their distal roots were removed. #15 H- or K-files (Dentsply Maillefer) were inserted into the mesiobuccal and mesiolingual canals of the teeth. Radiographs of the teeth were taken for the proximal view. Among them, type II canals were selected and divided into two subgroups, IIa and IIb. In type IIa, two separate canals merged into one canal before reaching the apex and in type IIb, two separate canals merged into one canal within the apical foramen. The radius and angle of curvature of specimens were examined. RESULTS: In type II, mean radius of curvature in mesiolingual and mesiobuccal canals were 2.82 mm and 3.58 mm, respectively. The radius of the curvature of mesiolingual canals were significantly smaller than that of mesiobuccal canals in type II, and especially in type IIa. However, there were no statistically significant differences in radius of curvature between mesiobuccal and mesiolingual canals in type IIb and there were no significant differences in angle of curvature between type IIa and IIb. CONCLUSION: In this study, type II mesial canals of mandibular molars showed severe curvature in the proximal view. Especially, mesiolingual canals of type IIa had more abrupt curvature than mesiobuccal canals at the apical one third.

A new way to study the motion of interventricular septum by echocardiography / 中华超声影像学杂志

Objective To evaluate the effect of normal respiration on motion and disfiguration of interventricular septum (IVS) by observing the change of interventricular septum radius of curvature (IVSRC). Methods The 2D short-axis images at chordae tendineae of mitral valve were recorded during inspiration and expiration respectively by Acuson Sequoia 512 in 21 normal subjects. Speed of blood flow of each valve, electrocardiogram and respiratory tracing were recorded simultaneously. Two doctors who were double-blind measured the IVSRC using self-designed software. Results During normal inspiration, the peak E velocity of mitral valve and the flow velocity of aortic valve decreased,while the peak E velocity of tricuspid valve and the flow velocity of pulmonary valve increased. The IVSRC curvatures were (25.914± 6.082)mm during inspiration, and (22.296±4.398)mm during expiration, there was difference in two respiration phases(P <0.0001). Conclusions IVSRC can be used to evaluate motion and disfiguration of IVS. It has a good repeatability and is an effective way to observe the change of pleural pressure which is produced by respiration.

Research in deformation and motion of interventricular septum by velocity vector imaging combining with radius of curvature and length of arc / 中华超声影像学杂志

Objective Radius of curvature (RC) and velocity vector imaging (VVI) were joined to evaluate the deformation and motion of interventricular septum(IVS). Methods VVI was performed in fifteen healthy volunteers and obtained dynamic images at chordae tendineae of mitral valve in short axis view. The images were stored and analyzed to obtain circumferential peak stain of IVS. In the same short axis view, the static images were captured at end-systole and end-diastole respectively before they were analyzed by self-made software. The length of arc and RC were measured automatically by the software, so the shortening rates of them could were calculated. Results The length of arc and RC were longer at end-diastole than those at end-systole(P<0.0001). The shortening rate of length of arc was compared with circumferential peak stain of IVS (P=0.123) and they were correlation (r = 0. 840, P = 0. 0001 ). Blant-Altman analysis indicated that the concordance was well. Conclusions The length of arc and RC can evaluate the deformation and motion of IVS.