Publishing Service

Polishing & Checking

Journal of Zhejiang University SCIENCE B

ISSN 1673-1581(Print), 1862-1783(Online), Monthly

Third molar-related knowledge, attitudes, behaviors, and medical history of 904 Chinese adults: a cross-sectional survey

Abstract: This study investigated the perceptions and medical history of third molars (M3s) and assessed the prevalence of visible M3s (V-M3s) among 904 Chinese adults. The enrolled participants were interviewed to complete a structural questionnaire focused on sociodemographic information and their understanding of, attitudes toward, behaviors regarding, and medical history with respect to M3s. In addition, the number of V-M3s in the cohort was determined by oral examination. Logistic regression analysis was performed to explore the association between individuals’ sociodemographic characteristics and their perception of M3s or the presence of V-M3s. The Chi-square test was used to compare the actions taken against symptomatic M3s and the corresponding outcomes among different groups divided according to respondents’ sociodemographic factors. In total, 904 completed questionnaires were gathered and analyzed. Nearly half (43.9%) of the respondents knew nothing about M3s, and only 12.7% provided correct answers to all the questions asked. Male sex, older age, occupation involving physical labor, and no previous dental experience were active factors in unawareness of M3s. Male sex was also significantly associated with the presence of at least one V-M3 and negative behavior about symptomatic M3s. In terms of medical history, 192 participants reported having had at least one M3 extracted (438 in total), and 72.6% of the M3s were removed due to the presence of related symptoms or pathologies. In conclusion, the population investigated had a shortage of knowledge about M3s and adopted negative attitudes and actions about M3-related problems.

Key words: Third molar; Knowledge; Attitude; Practice; Medical history; Prevalence

Chinese Summary  <13> 狭窄环形空间内浮力驱动微对流的动力学特性

作者:王延忠1,张亚萍1,杨凯2,鲁博佶1,高浩3
机构:1北京航空航天大学,机械工程及自动化学院,中国北京,100191;2北京卫星制造厂,中国北京,100094;3三明学院,机电工程学院,中国三明,365001
目的:液浮陀螺仪环形流道的宏微观特征影响内部浮油的动力学特性,与仪表精度水平密切相关。本文旨在探讨狭窄环形流道的间隙尺寸、粗糙高度、粗糙密度等因素对浮油流场、温度场、粘滞力矩的影响,为陀螺仪表的设计优化和精度提升提供理论参考。
创新点:1.抽取液浮陀螺仪内部环形流道的结构特征,建立流体域的流热耦合模型;2.提出一种表征壁面粗糙特征的方法,获取粗糙特征对浮油流热特性的影响规律。
方法:1.通过分析液浮陀螺仪的结构和工况,建立简化的理论分析模型(图2);2.采用几何微圆构造粗糙特征,并定义壁面粗糙参数(图3);3.建立陀螺仪环形流体域的流热耦合模型;4.通过耦合模型的求解计算,分析壁面宏微观尺寸对浮油动力学特性的影响规律。
结论:1.间隙效应对粘滞力矩的影响大于粘温效应,且力矩随着间隙尺寸的增加先增大后减小,最后趋于稳定;2.流道壁面粗糙度对浮油动力学特性有显著影响,粗糙度高度对粘滞力矩的影响大于粗糙度密度对粘滞力矩的影响。

关键词组:液浮陀螺仪;环形通道;粗糙特征;流体阻力


Share this article to: More

Go to Contents

References:

<Show All>

Open peer comments: Debate/Discuss/Question/Opinion

<1>

Please provide your name, email address and a comment





DOI:

10.1631/jzus.B2200617

CLC number:

Download Full Text:

Click Here

Downloaded:

471

Download summary:

<Click Here> 

Downloaded:

181

Clicked:

633

Cited:

0

On-line Access:

2023-06-26

Received:

2022-12-04

Revision Accepted:

2023-02-07

Crosschecked:

2023-09-26

Journal of Zhejiang University-SCIENCE, 38 Zheda Road, Hangzhou 310027, China
Tel: +86-571-87952276; Fax: +86-571-87952331; E-mail: jzus@zju.edu.cn
Copyright © 2000~ Journal of Zhejiang University-SCIENCE