Variations in the Cross-Sectional Shape of the Apical Thirds of the Root Canals in Maxillary and Mandibular Teeth

Abstract Objective: To determine the prevalence of cross-sectional variations in the apical thirds of the root canals in maxillary and mandibular teeth. Material and Methods: Eighty tooth samples (maxillary second premolar, maxillary first molar, and mandibular first molar) were scanned using micro-computed tomography. The apical third area of each root canal was sectioned and the maximum and minimum diameters were calculated from the mesiodistal and buccolingual diameters. The shapes were categorized as a round, oval, long oval, and flat based on the ratios obtained. Results: The most common shape of the apical third of the root canals in the maxillary second premolars was oval (66.7%), followed by long oval (24.6%), flat (7%), and round (1.7%). The corresponding values in the mesiobuccal root of the maxillary first molars were oval (68.2%), long oval (22.7%), flat (9.1%), 94.1% of the distobuccal roots were oval, while the remaining were long oval (5.9%). All the palatal root canals were oval. In the mesiobuccal root of the mandibular first molars, 47.4% were long oval in shape, followed by 36.8% oval and 15.8% flat canals. All the mesiolingual root canals were oval, whereas, in the distal root, 68.4% were oval, 21.1% long oval, and 10.5% were flat. Conclusion: The oval shape was most commonly observed in the majority of the root canals. Knowledge about the apical anatomy of the root can help the operator improve the root canal treatment's success.

The Differences in Paranasal Sinus Pneumatization after Adolescence in Korean / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The embryological development of paranasal sinuses has been revealed by previous articles although few studies have reported on the differences of paranasal sinus pneumatization according to age after adolescence. We evaluated changes in paranasal sinus pneumatization in the ages ranging from 10s to over 60s. SUBJECTS AND METHOD: A retrospective review was carried out for patients who underwent osteomeatal unit three-dimensional computed tomography from January 2008 to March 2017. Two hundred and forty patients were selected and matched for age, sex, and existence of sinusitis. The biggest cross-sectional area (CSA) of each sinus was selected from each patient, which was then corrected to the size of the face. CSA and corrected CSA (cCSA) values were used together for analysis. RESULTS: CSAs of frontal, maxillary, sphenoid sinuses gradually increased in the ages ranging in the 30s, and then significantly decreased from those in the 40s onwards. In particular, these tendencies were statistically significant in all types of sinuses between the 30s and 40s, (p0.05). CSAs in patients with chronic sinusitis were not different from those in patients without chronic sinusitis in every sinus and all age groups (p>0.05). CONCLUSION: This study shows that older people have smaller sinuses, and sex difference and existence of sinusitis have no effect on the pneumatization of the sinuses.

Segmentation of Cerebral Gyri in the Sectioned Images by Referring to Volume Model

Authors had prepared the high-quality sectioned images of a cadaver head. For the delineation of each cerebral gyrus, three-dimensional model of the same brain was required. The purpose of this study was to develop the segmentation protocol of cerebral gyri by referring to the three-dimensional model on the personal computer. From the 114 sectioned images (intervals, 1 mm), a cerebral hemisphere was outlined. On MRIcro software, sectioned images including only the cerebral hemisphere were volume reconstructed. The volume model was rotated to capture the lateral, medial, superior, and inferior views of the cerebral hemisphere. On these four views, areas of 33 cerebral gyri were painted with colors. Derived from the painted views, the cerebral gyri in sectioned images were identified and outlined on the Photoshop to prepare segmented images. The segmented images were used for production of volume and surface models of the selected gyri. The segmentation method developed in this research is expected to be applied to other types of images, such as MRIs. Our results of the sectioned and segmented images of the cadaver brain, acquired in the present study, are hopefully utilized for medical learning tools of neuroanatomy.

A Proposal of New Reference System for the Standard Axial, Sagittal, Coronal Planes of Brain Based on the Serially-Sectioned Images

Sectional anatomy of human brain is useful to examine the diseased brain as well as normal brain. However, intracerebral reference points for the axial, sagittal, and coronal planes of brain have not been standardized in anatomical sections or radiological images. We made 2,343 serially-sectioned images of a cadaver head with 0.1 mm intervals, 0.1 mm pixel size, and 48 bit color and obtained axial, sagittal, and coronal images based on the proposed reference system. This reference system consists of one principal reference point and two ancillary reference points. The two ancillary reference points are the anterior commissure and the posterior commissure. And the principal reference point is the midpoint of two ancillary reference points. It resides in the center of whole brain. From the principal reference point, Cartesian coordinate of x, y, z could be made to be the standard axial, sagittal, and coronal planes.

Evaluation of normal masseter muscles on ultrasonography / 대한구강악안면방사선학회지

PURPOSE: To assess the internal echo intensity and morphological variability of masseter muscles on ultrasonography and to establish diagnostic criterion of estimation. MATERIALS AND METHODS: Participants consisted of 50 young adults (male 25, female 25) without pathologic conditions and with full natural dentitions. Sonographic examinations were done with real time ultrasound equipment as Logiq 500 (GE Medical Systems, Seoul, Korea) at 3 parts according to lines paralleling with ala-tragus line as reference line. The thickness and area of masseter muscles according to reference line in cross-sectional images were measured at rest and at maximum contraction. The visibility and width of the internal echogenic intensity of the masseter muscles were also assessed and the muscle appearance was classified into 4 types. Data were statistically analyzed by paired t-test and chi-square-test. RESULTS: 1. When comparing the thickness and area of masseter muscles concerning with gender, there was few significant difference between right and left sides, however, there were significant differences between males and females except for the greatest thickness of left side. 2. The changes of the greatest thickness and the area between rest and maximum contraction showed that the part of the least thickness manifested more increase at maximum contraction. 3. Each part the manifestations of the internal echogenic intensity of the masseter muscles were different depending on the locations. But there was no statistically significance. CONCLUSION: Changes of muscles thickness with contraction and internal echogenic intensity with locations showed great disparity within the masseter muscles, which will be diagnostic criteria for pathophysiologic and anatomic changes of masseter muscles.

Ultrasound biomicroscopy in the comparison of the anterior segment morphometry before and after pars plana vitrectomy

PURPOSE: To determine if pars plana vitrectomy induces long-term changes in the anterior segment anatomy by means of ultrasound biomicroscopy. METHODS: A prospective case series study was undertaken of consecutive patients referred to a tertiary eye care centre for pars plana vitrectomy as the only procedure. Twenty eyes of 20 patients undergoing pars plana vitrectomy alone were studied by ultrasound biomicroscopy. Silicone oil or scleral buckle was not used in any of the included cases. The following morphometric parameters were compared before and after 3 months of surgery: anterior chamber depth, angle-opening distance at 500 æm from the scleral spur, trabecular-ciliary process distance, ciliary body thickness at 1, 2 and 3 millimeters from the scleral spur and measurement of the supraciliary space thickness, when fluid was detected. RESULTS: No statistically significant differences were found between the preoperative and the postoperative morphometric parameters. CONCLUSION: Uncomplicated pars plana vitrectomy does not induce any long-term change on anterior segment morphometry. Based on these findings, the normal long-term pattern to be expected after pars plana vitrectomy is the conservation of the preoperative morphometry.

OBJETIVOS: O objetivo do presente estudo foi determinar, por meio da biometria ultra-sônica (UBM), se a vitrectomia via "pars plana" pode induzir alterações permanentes na anatomia do segmento anterior. MÉTODOS: Foi realizado estudo prospectivo, analisando-se uma série consecutiva de pacientes, encaminhados para um centro de referência terciário para serem submetidos a vitrectomia via "pars plana" como único procedimento. Vinte olhos de 20 pacientes a serem submetidos a vitrectomia como único procedimento foram estudados pela biomicroscopia ultra-sônica. Oleo de silicone ou introflexão escleral não foram usados em nenhum dos casos incluídos. Os seguintes parâmetros morfométricos foram comparados antes e após 3 meses da cirurgia: profundidade da câmara anterior, abertura do ângulo a 500 æm do esporão escleral, distância trabéculo-processos ciliares, espessura do corpo ciliar a 1, 2 e 3 milímetros do esporão escleral e medida da espessura do espaço supraciliar, quando fluido foi detectado. RESULTADOS: Não foram encontradas diferenças estatisticamente significativas entre os períodos pré e pós-operatório para os parâmetros morfométricos estudados. CONCLUSÃO: A vitrectomia via "pars plana" não-complicada não induz alterações permanentes na morfometria do segmento anterior. Com base nestes achados, o padrão normal esperado após a vitrectomia via "pars plana" é a conservação da morfometria pré-operatória.

Computer tomography characteristics of one-side chronic ethmoid-maxillary sinusitis / 中国耳鼻咽喉头颈外科

OBJECTIVE To investigate the characteristic computer tomography (CT) changes in cases of one-sided chronic ethmoid-maxillary sinusitis. METHODS The CT results of 76 patients diagnosed with one-sided chronic ethmoid-maxillary sinusitis were reviewed. RESULTS There were 51 patients with one-sided chronic ethmoid-maxillary sinusitis on the right side and 25 patients on the left side. There were 48 cases of obstruction of the ostium of the maxillary sinus. The characteristics of soft tissue lesions were mucosa hypertrophy and polypiform density spot. There were 9 cases with bony destruction. CONCLUSION More cases with pathologic changes on the left side were found. The obstruction of the ostium of the maxillary sinus and the abnormal anatomy of ostiomeatal complex were identified as important anatomical features of one-sided chronic ethmoid-maxillary sinusitis.

Localization of adult cerebral central sulcus on the coronal MR imaging / 中华放射学杂志

Objective To localize precisely cerebral central sulcus on the coronal MR imaging. Methods The serieses of 4 mm thickness coronal sections and coronal MR images of brain were prepared on 30 cadaver heads. The preparation of the brain slices in correspondence with MR scan took the line perpendicular to the midpoint of intercommissural line as base one. The important cerebral gyri of cadaver were painted different colors. The coronal MR images of 6 volunteers were also prepared. The localization of central sulcus on the coronal sections was studied by the comparison of MR images with serial coronal sections of the brains. Results On the section of the central sulcus appearing for the first time, the appearing rate of dorsal thalamus was: left side 93%, right side 97%; the appearing rate of pyramidal tract was: left side 20%, right side 13%. The central sulcus almost disappeared on the section through the posterior border of splenium of corpus callosum, the appearing rate of the central sulcus on the superolateral surface was 33% on the both sides. Conclusion The central sulcus appears for the first time on the 1-2 sections which the dorsal thalamus appears on but the pyramidal tract doesn′t appear. On the section through pyramidal tract, the superior frontal, precentral and postcentral gyri can be identified according to the three medullary branches on superolateral surface of cerebral hemispheres. The central sulcus has almost disappeared on the section through the posterior border of splenium of corpus callosum.