base angle
Recently Published Documents


TOTAL DOCUMENTS

52
(FIVE YEARS 8)

H-INDEX

7
(FIVE YEARS 0)

2021 ◽  
Vol 12 ◽  
Author(s):  
Heidi Arponen ◽  
Marjut Evälahti ◽  
Outi Mäkitie

BackgroundBiallelic mutations in the non-coding RNA gene RMRP cause Cartilage-hair hypoplasia (CHH), a rare skeletal dysplasia in which the main phenotypic characteristic is severe progressive growth retardation.ObjectiveThis study compared the cranial dimensions of individuals with CHH to healthy subjects.MethodsLateral skull radiographs of 17 patients with CHH (age range 10 to 59 years) and 34 healthy individuals (age range 10 to 54 years) were analyzed for relative position of the jaws to skull base, craniofacial height and depth, as well as vertical growth pattern of the lower jaw, anterior cranial base angle, and the relationship between the cervical spine and skull base.ResultsWe found that the length of the upper and lower jaws, and clivus were significantly decreased in patients with CHH as compared to the controls. Anterior cranial base angle was large in patients with CHH. Basilar invagination was not found.ConclusionThis study found no severe craniofacial involvement of patients with CHH, except for the short jaws. Unexpectedly, mandibular deficiency did not lead to skeletal class II malocclusion.Clinical ImpactAlthough the jaws were shorter in patients with CHH, they were proportional to each other. A short posterior cranial base was not associated with craniocervical junction pathology.



2021 ◽  
pp. 105566562110535
Author(s):  
Chandnee Murugan ◽  
Vignesh Kailasam

Background: Diverse findings have been reported for the cranial base angle (CBA) in patients with CLP (cleft lip and palate) and non-CLP controls. Objective: The aim of this study is to assess and evaluate the CBA in patients with CLP and non-CLP controls. Methods: Data from PubMed, OVID Technologies, Inc., Cochrane, Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS), Scopus, Web of Science, and EMBASE for Excerpta Medica dataBASE (EMBASE) with relevant terms was extracted until December 31, 2020. Inclusion criteria were data of patients with non-syndromic unilateral cleft lip and palate (UCLP) and bilateral cleft lip and palate (BCLP). In the case of UCLP and BCLP, patients with craniofacial syndromes were excluded. The study proposal was registered with PROSPERO (Registration number: CRD42021228632). Results: Fifteen studies with a total of 2032 participants were included for the systematic review and 14 studies with a total of 1972 participants were included for the meta-analysis. The risk of bias was assessed using the Modified Newcastle Ottawa scale under seven domains by two authors. Thirteen studies were graded as “good” and two as “satisfactory.” The CBA in patients with CLP were greater than the non CLP Class I controls in six of the 15 studies. CBA was greater in patients with CLP than non-CLP controls by 1.21° (95% CI of 0.19-2.22). Meta-analysis reported considerable heterogeneity (I2 = 86%). Anterior (ACB) and posterior cranial base (PCB) lengths were shorter in patients with CLP than in the non-cleft Class I controls by 2.14 mm (95% CI of 0.99-3.30) and 2.06 mm (95% CI of 1.52-2.60), respectively. Conclusion: Most studies were graded as good. Patients with CLP had greater CBA and shorter ACB and PCB lengths when compared to non-CLP controls.



2021 ◽  
Vol 25 (5) ◽  
pp. 538-548
Author(s):  
N. V. Vulykh ◽  
A. N. Vulykh

The present paper aims to describe shape changes in a microroughness model developed for the working surfaces of parts at degrees of deformation commensurate with the height of the original microprofile; to establish how the degree of microprofile upsetting affects its shape under constrained loading conditions; as well as to estimate the stress state of the microprofile by stress intensity. A numerical model describing the surface microprofile of parts was calculated using the ANSYS Workbench environment. Lead, tin, aluminum, and copper were used as microprofile materials. In addition, microprofile upsetting was computer simulated under constrained loading conditions. The valley bottom was found to rise at a 10–20% microprofile upsetting by 0.213–0.275 mm relative to the original profile height, depending on its material. The relative length of the smoothed microprofile section amounted to 0.786–0.925 mm of its original length. The base angle of the deformed microprofile reached 570 and 800 for copper and lead models, respectively. The depth of valleys ranged from 1.4 mm (23% of the original profile height) for lead models and from 1.8 mm (30% of the original profile height) for copper models. In the case of maximum microprofile upsetting, an increase in the yield strength of microrough material from 10 to 60 MPa contributed to a reduction in the base angle of the deformed microprofile, as well as relative length and the vertical rise of microprofile valleys at their highest point. No interlocking of lateral microprofile surfaces was observed. At a 50% upsetting, the stress state of the microprofile exceeded its ultimate strength by 4–8 times. The shape changes simulated for the microprofile from plastic metallic materials are described. The performed numerical simulation correlates well with the experimental results obtained for lead microprofile models. It is worth noting that the complete smoothing of the microprofile is likely to occur through the rise of valleys and the approaching of its lateral surfaces. The study results can be used for designing and manufacturing valve gate assemblies.



2021 ◽  
Vol 11 (4) ◽  
pp. 55-59
Author(s):  
Olga Aleshkina ◽  
Tatiana Bikbaeva ◽  
Anton Devyatkin ◽  
Marina Markeeva ◽  
Tatyana Zagorovskaya ◽  
...  

Details of the morpho- & topometric variability of the skull elements and soft tissue formations in the area of the sphenoid bone body, as well as their relationship, serve as the basis for the choice of proper surgical accesses to the respective area. The aim of this study was to identify the typical variability of morphometric parameters and the volume ratio between the pituitary gland and the Turkish saddle pituitary fossa in mature age adults. The method of computer craniometry (involving 100 MRI of people of the first and second periods of their mature age, 22–60) was employed to study the typical variability of the pituitary fossa and pituitary gland linear parameters, regardless of gender. The obtained data revealed that the regularity of morphometric variability and the volume ratio of the pituitary gland and the pituitary fossa depend on the skull base bending angle.



Author(s):  
Agnieszka Jankowska ◽  
Joanna Janiszewska-Olszowska ◽  
Katarzyna Grocholewicz

Nose shape, size, and inclination influence facial appearance, but few studies concern the relationship between the nasal profile and craniofacial structures. The objective of this study was to analyze association of nasal cephalometric variables with skeletal structures, age, and sex. Cephalometric and nasal analysis was performed in 386 Polish orthodontic patients (aged 9–25 years). Student t-test and Mann–Whitney test were used to compare quantitative variables and Pearson’s or Spearman’s correlation coefficients—to find correlations. Soft tissue facial convexity angle correlates to Holdaway ratio, ANB (A-Nasion-B), and Wits appraisal. Nasal dorsum axis, nose length, nose depth (1) and nose depth (2), nose hump, lower dorsum convexity, and columella convexity increase with age. Nasal base angle, nasolabial angle, nasomental angle, soft tissue facial convexity and nasal bone angle decrease with age. Nasal base angle and nasomental angle are smaller in females. Thus, a relationship exists between nasal morphology and sagittal jaw configuration. Nasal parameters significantly change with age. Sexual dimorphism characterizes nasal bone angle and nasomental angle.



2021 ◽  
Vol 32 (2) ◽  
pp. 581-586
Author(s):  
Xiaona Lu ◽  
Antonio Jorge Forte ◽  
Omar Allam ◽  
Kitae Eric Park ◽  
Michael Alperovich ◽  
...  


Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 365
Author(s):  
Seon-Hee Shin ◽  
Hyung-Seog Yu ◽  
Jung-Yul Cha ◽  
Jae-Sung Kwon ◽  
Chung-Ju Hwang

The accurate expression of bracket prescription is important for successful orthodontic treatment. The aim of this study was to evaluate the accuracy of digital scan images of brackets produced by four intraoral scanners (IOSs) when scanning the surface of the dental model attached with different bracket materials. Brackets made from stainless steel, polycrystalline alumina, composite, and composite/stainless steel slot were considered, which have been scanned from four different IOSs (Primescan, Trios, CS3600, and i500). SEM images were used as references. Each bracket axis was set in the reference scan image, and the axis was set identically by superimposing with the IOS image, and then only the brackets were divided and analyzed. One-way analysis of variance (ANOVA) was used to compare the differences. The difference between the manufacturer’s nominal torque and bracket slot base angle was 0.39 in SEM, 1.96 in Primescan, 2.04 in Trios, and 5.21 in CS3600 (p < 0.001). The parallelism, which is the difference between the upper and lower angles of the slot wall, was 0.48 in SEM, 7.00 in Primescan, 5.52 in Trios, 6.34 in CS3600, and 23.74 in i500 (p < 0.001). This study evaluated the accuracy of the bracket only, and it must be admitted that there is some error in recognizing slots through scanning in general.



2021 ◽  
Vol 70 (12) ◽  
pp. 126101-126101
Author(s):  
Li Wen ◽  
◽  
Ma Xiao-Jing ◽  
Xu Jin-Liang ◽  
Wang Yan ◽  
...  
Keyword(s):  


Author(s):  
Seon-Hee Shin ◽  
Hyung-Seog Yu ◽  
Jung-Yul Cha ◽  
Jae-Sung Kwon ◽  
Chung-Ju Hwang

Accurate expression of bracket prescription is important for successful orthodontic treatment. The aim of this study was to evaluate the accuracy of digital scan images of brackets produced by four different intraoral scanners (IOSs) in terms of the height, position, and angle of the bracket slot when scanning the surface of dental model attached with bracket materials made from different composition of materials. Brackets made from stainless steel, polycrystalline alumina, composite and composite/stainless steel slot were considered, which have been scanned from 4 different IOSs (Primescan, Trios, CS3600 and i500). SEM images were used as references. Each bracket axis was set in the reference scan image, and the axis was set identically by superimposing with the IOS image, and then only the brackets were divided and analyzed. The difference between the manufacturer's nominal torque and bracket slot base angle was 0.39 in SEM, 1.96 in Primescan, 2.04 in Trios, and 5.21 in CS3600 (P &lt;0.001). The parallelism, which is the difference between the upper and lower angles of the slot wall, was 0.55 in SEM, 7.55 in Primescan, 6.74 in Trios3, 6.59 in CS3600, and 24.95 in i500 (p &lt;0.001). This study evaluated the accuracy of the bracket only and it must be admitted that there is some error in recognizing slots through scanning in general





Sign in / Sign up

Export Citation Format

Share Document