Purpose:Recently,global science has shown an increasing open trend,however,the characteristics of research integrity of open access(OA)publications have rarely been studied.The aim of this study is to compare the char...Purpose:Recently,global science has shown an increasing open trend,however,the characteristics of research integrity of open access(OA)publications have rarely been studied.The aim of this study is to compare the characteristics of retracted articles across different OA levels and discover whether OA level influences the characteristics of retracted articles.Design/methodology/approach:The research conducted an analysis of 6,005 retracted publications between 2001 and 2020 from the Web of Science and Retraction Watch databases.These publications were categorized based on their OA levels,including Gold OA,Green OA,and non-OA.The study explored retraction rates,time lags and reasons within these categories.Findings:The findings of this research revealed distinct patterns in retraction rates among different OA levels.Publications with Gold OA demonstrated the highest retraction rate,followed by Green OA and non-OA.A comparison of retraction reasons between Gold OA and non-OA categories indicated similar proportions,while Green OA exhibited a higher proportion due to falsification and manipulation issues,along with a lower occurrence of plagiarism and authorship issues.The retraction time lag was shortest for Gold OA,followed by non-OA,and longest for Green OA.The prolonged retraction time for Green OA could be attributed to an atypical distribution of retraction reasons.A comparative study on characteristics of retracted publications across different open access levels Research limitations:There is no exploration of a wider range of OA levels,such as Hybrid OA and Bronze OA.Practical implications:The outcomes of this study suggest the need for increased attention to research integrity within the OA publications.The occurrences offalsification,manipulation,and ethical concerns within Green OA publications warrant attention from the scientific community.Originality/value:This study contributes to the understanding of research integrity in the realm of OA publications,shedding light on retraction patterns and reasons across different OA levels.展开更多
Purpose:The notable increase in retraction papers has attracted considerable attention from diverse stakeholders.Various sources are now offering information related to research integrity,including concerns voiced on ...Purpose:The notable increase in retraction papers has attracted considerable attention from diverse stakeholders.Various sources are now offering information related to research integrity,including concerns voiced on social media,disclosed lists of paper mills,and retraction notices accessible through journal websites.However,despite the availability of such resources,there remains a lack of a unified platform to consolidate this information,thereby hindering efficient searching and cross-referencing.Thus,it is imperative to develop a comprehensive platform for retracted papers and related concerns.This article aims to introduce“Amend,”a platform designed to integrate information on research integrity from diverse sources.Design/methodology/approach:The Amend platform consolidates concerns and lists of problematic articles sourced from social media platforms(e.g.,PubPeer,For Better Science),retraction notices from journal websites,and citation databases(e.g.,Web of Science,CrossRef).Moreover,Amend includes investigation and punishment announcements released by administrative agencies(e.g.,NSFC,MOE,MOST,CAS).Each related paper is marked and can be traced back to its information source via a provided link.Furthermore,the Amend database incorporates various attributes of retracted articles,including citation topics,funding details,open access status,and more.The reasons for retraction are identified and classified as either academic misconduct or honest errors,with detailed subcategories provided for further clarity.Findings:Within the Amend platform,a total of 32,515 retracted papers indexed in SCI,SSCI,and ESCI between 1980 and 2023 were identified.Of these,26,620(81.87%)were associated with academic misconduct.The retraction rate stands at 6.64 per 10,000 articles.Notably,the retraction rate for non-gold open access articles significantly differs from that for gold open access articles,with this disparity progressively widening over the years.Furthermore,the reasons for retractions have shifted from traditional individual behaviors like falsification,fabrication,plagiarism,and duplication to more organized large-scale fraudulent practices,including Paper Mills,Fake Peer-review,and Artificial Intelligence Generated Content(AIGC).Research limitations:The Amend platform may not fully capture all retracted and concerning papers,thereby impacting its comprehensiveness.Additionally,inaccuracies in retraction notices may lead to errors in tagged reasons.Practical implications:Amend provides an integrated platform for stakeholders to enhance monitoring,analysis,and research on academic misconduct issues.Ultimately,the Amend database can contribute to upholding scientific integrity.Originality/value:This study introduces a globally integrated platform for retracted and concerning papers,along with a preliminary analysis of the evolutionary trends in retracted papers.展开更多
One of the most challenging factors affecting impression quality and good marginal fit is the gingival retraction method, which aims to separate the gingiva from the tooth to expose the finishing line of the prepared ...One of the most challenging factors affecting impression quality and good marginal fit is the gingival retraction method, which aims to separate the gingiva from the tooth to expose the finishing line of the prepared tooth. Bleeding and contamination from the crevicular fluid may compete for space with the impression material within the sulcus, leading to indistinct preparations and a lack of detail at the margin. In addition, such procedures might damage the PDL and cause permanent recession. Flowable composite cable, as opposed to traditional retraction cords, offers the proper marginal seal and visibility during the impression record because of its lower viscosity, improved adaptability, and elastic properties. The aim of this report is to present a brand-new, innovative method for controlling gingival hemorrhage in addition to the gingival retraction in restorative and prosthodontic treatment by utilizing a flowable composite during the final impression record procedure. In these case reports, the flowable composite cord technique is used instead of traditional gingival cords to modify and refine the gingival tissue before taking the traditional final impression or digital scan. Two cases were done for patients undergoing fixed prosthodontics and veneer treatment within a 2-year follow-up period. In addition, the flowable composite cord was used as temporary restoration before the final prosthetic cementation or under the provisional crowns. As a result, clean and healthy gingival tissues render cementation of the final prosthesis quicker and easier to perform. The patients in both cases claimed that their prosthodontic treatments, which involved the application of a flowable composite cord to temporarily retraction the gingiva, had produced good outcomes at the yearlong follow-up. In conclusion, the flowable composite cord technique is found to be a useful tool to improve the quality of impressions in fixed prosthodontics by providing excellent access for impression material to record fine details of the finish line of the prepared tooth structure, and to alter the inflamed tissue into a healthy tissue.展开更多
In this retraction note,we describe the World Journal of Clinical Cases(WJCC)Editorial Office’s decision and reason for retracting an article published in WJCC,volume 12,issue 13.
The authors have decided to retract the article published on World J Gastrointest Oncol(2023)for further consideration due to data errors and some misunderstandings in communication.
Background:Upper eyelid retraction is a challenging complication of cosmetic upper eyelid blepharoplasty.To avoid extra trauma,we developed a new technique for correcting iatrogenic upper eyelid retraction by postmigr...Background:Upper eyelid retraction is a challenging complication of cosmetic upper eyelid blepharoplasty.To avoid extra trauma,we developed a new technique for correcting iatrogenic upper eyelid retraction by postmigrating a compound flap of the orbicularis muscle and fascia(OFC)on the anterior surface of the tarsal plate.This method extends the aponeurosis of the levator palpebrae superioris muscle(LPS),which can achieve a good correction for post-blepharoplasty retraction.Methods:We collected data from 15 patients with mild to moderate iatrogenic upper eyelid retraction who were treated at our hospital between February 2017 and December 2019.The OFC was used to replace the missing part of the LPS,and post-migration of the LPS and fixation of the OFC to the tarsal margin were conducted.Postoperative outcome measurements included postoperative binocular symmetry,double eyelid smoothness,eyelid fullness,margin reflex distance(MRD1),degree of eyelid closure,and exposure keratitis.The patients were followed-up at seven days,one month,and six months postoperatively.Results:One patient with moderate eyelid retraction showed undercorrection 6 months postoperatively,with the upper eyelid margin located at the upper edge of the pupil.The remaining patients had the upper eyelid margin stabilized at 1.0–2.0 mm below the upper corneal margin.Other observational indicators were satisfactory,including binocular symmetry,double eyelid fluency,and eyelid fullness.During the follow-up,no exposure keratitis was identified.The MRD1 indexes after the operation were significantly different(P<0.001)from those before the procedure.Conclusions:Extension and post-migration of the LPS using the orbicularis muscle and OFC structure can effectively correct mild iatrogenic eyelid retraction after ptosis with less damage and good postoperative eyelid morphology and closure function.展开更多
We have decided to retract the above article because we have concluded that the limitations in our data sample may potentially lead to misinterpretation of the findings.
Purpose: The number of retracted papers from Chinese university-affiliated hospitals is increasing, which has raised much concern. The aim of this study is to analyze the retracted papers from university-affiliated ho...Purpose: The number of retracted papers from Chinese university-affiliated hospitals is increasing, which has raised much concern. The aim of this study is to analyze the retracted papers from university-affiliated hospitals in China’s mainland from 2000 to 2021. Design/methodology/approach: Data for 1,031 retracted papers were identified from the Web of Science Core collection database. The information of the hospitals involved was obtained from their official websites. We analyzed the chronological changes, journal distribution, discipline distribution and retraction reasons for the retracted papers. The grade and geographic locations of the hospitals involved were explored as well.Findings: We found a rapid increase in the number of retracted papers, while the retraction time interval is decreasing. The main reasons for retraction are plagiarism/self-plagiarism(n=255), invalid data/images/conclusions(n=212), fake peer review(n=175) and honesty error(n=163). The disciplines are mainly distributed in oncology(n=320), pharmacology & pharmacy(n=198) and research & experimental medicine(n=166). About 43.8% of the retracted papers were from hospitals affiliated with prestigious universities. Research limitations: This study fails to differentiate between retractions due to honest error and retractions due to research misconduct. We believe that there is a fundamental difference between honest error retractions and misconduct retractions. Another limitation is that authors of the retracted papers have not been analyzed in this study.Practical implications: This study provides a reference for addressing research misconduct in Chinese university-affiliated hospitals. It is our recommendation that universities and hospitals should educate all their staff about the basic norms of research integrity, punish authors of scientific misconduct retracted papers, and reform the unreasonable evaluation system.Originality/value: Based on the analysis of retracted papers, this study further analyzes the characteristics of institutions of retracted papers, which may deepen the research on retracted papers and provide a new perspective to understand the retraction phenomenon.展开更多
Cancer research is occasionally described as being in a reproducibility crisis.The cancer literature has ample papers retracted due to misconduct,including the use of paper mills,invalid authorship,or fake data.The ob...Cancer research is occasionally described as being in a reproducibility crisis.The cancer literature has ample papers retracted due to misconduct,including the use of paper mills,invalid authorship,or fake data.The objective of this paper was to gain an appreciation of the balance of retractions and associated retraction notices of 23 retracted Cancer Biotherapy and Radiopharmaceuticals papers associated with paper mills.By 23 March 2023,these retracted papers had already accumulated 287 citations according to Web of Science Core Collection,253 according to Scopus,and 365 according to Google Scholar,i.e.,metrically speaking,they were highly rewarded.All authors had an affiliation(71%being a hospital)in China.Most(12/21;57%)of corresponding authors had emails with a@163.com suffix.Four of the retraction notices(i.e.,17%)explicitly indicated paper mills as a reason for retraction although,in general,the retraction notices lacked details and background that could assist readers’understanding of the retractions.展开更多
BACKGROUND Mandibular retraction is the main etiological mechanism of class II malocclusion in China and the subsequent distal molar relationship can cause functional discomfort in mastication,breathing and the tempor...BACKGROUND Mandibular retraction is the main etiological mechanism of class II malocclusion in China and the subsequent distal molar relationship can cause functional discomfort in mastication,breathing and the temporomandibular joint.The use of mandibular advancement(MA)devices has recently emerged as an adolescent mandibular retraction treatment;however,current studies regarding the effect thereof are relatively few,and there is lack of sufficient clinical support.AIM To investigate the clinical effect of invisalign MA on the treatment of mandibular retraction in adolescents.METHODS This study included 30 adolescent patients who underwent treatment with the MA appliances from December 2017 to June 2021.The lateral cephalometric data before and after treatment were collected and imported into Dolphin Imaging software.The changes were measured by linear measurement superimposed with lateral cephalometric trajectory based on the Pancherz technology.RESULTS There was no significant difference in the length and position of maxilla before and after the treatment.The position of the mandible moved 3.13 mm,the length increased 4.14 mm,the mandibular ramus length increased 4.09 mm,the body length increased 4.25 mm,and the position of the condyle moved 1.03 mm forward after treatment.Additionally,changes in the incisor sagittal position and labial inclination were observed.The position of the upper incisor point moved back 1.33 mm,without statistical difference,the inclination and tooth angle decreased by 3.44°and 4.06°,respectively;the position of the lower incisor point was moved 2.98 mm,and the inclination and tooth angle increased by 2.62°and 1.23°,respectively.Furthermore,changes in the incisor overjet and molar relationship were seen.Overjet decreased by 4.31 mm,of which 1.78 mm was due to dental factors,accounting for 41.3%of the effect as opposed to 58.7%due to skeletal factors.Molar relationship improved 3.87 mm,with 1.34 mm due to dental factors,and dental and skeletal factors were accounted for 34.6%and 65.4%of the effect,respectively.CONCLUSION For adolescent patients with mandible retraction,invisalign MA can effectively promote the mandible growth,and it was proven to be mainly due to skeletal effects.展开更多
Casing-while-drilling(CWD)with down the hole(DTH)hammer drilling technology has been widely used in unconsolidated formations,due to its advantages in protecting the borehole wall,excellent rock cuttings capacity,and ...Casing-while-drilling(CWD)with down the hole(DTH)hammer drilling technology has been widely used in unconsolidated formations,due to its advantages in protecting the borehole wall,excellent rock cuttings capacity,and fast penetration rate in hard rock.As an important component of the CWD system,the structure of the retractable drill bit needs not only to ensure to form stronger reverse circulation,but also to be expandable or retractable as needed,otherwise the drill bit cannot be lift and put down smoothly in the casing,and may lead to drilling accidents.This paper developed a new type of reverse circulation DTH hammer drill bit used for CWD drilling technology.The retractable performance of this type of drill bit is studied using ADAMS software.The results show that it is smoothly expandable and retractable as designed under the conditions of the weight of the bit(WOB)of 0.5–2.0 t and the rotation speed of 30–60 r/min.To investigate the reverse circulation effect of the drill bit,Fluent software was used to simulate the flow characteristic inside it.The simulation results indicated that it can form strong reverse circulation,and the entrainment ratio h can reach 9.5%.展开更多
基金the National Social Science Foundation of China(No.22CTQ032).
文摘Purpose:Recently,global science has shown an increasing open trend,however,the characteristics of research integrity of open access(OA)publications have rarely been studied.The aim of this study is to compare the characteristics of retracted articles across different OA levels and discover whether OA level influences the characteristics of retracted articles.Design/methodology/approach:The research conducted an analysis of 6,005 retracted publications between 2001 and 2020 from the Web of Science and Retraction Watch databases.These publications were categorized based on their OA levels,including Gold OA,Green OA,and non-OA.The study explored retraction rates,time lags and reasons within these categories.Findings:The findings of this research revealed distinct patterns in retraction rates among different OA levels.Publications with Gold OA demonstrated the highest retraction rate,followed by Green OA and non-OA.A comparison of retraction reasons between Gold OA and non-OA categories indicated similar proportions,while Green OA exhibited a higher proportion due to falsification and manipulation issues,along with a lower occurrence of plagiarism and authorship issues.The retraction time lag was shortest for Gold OA,followed by non-OA,and longest for Green OA.The prolonged retraction time for Green OA could be attributed to an atypical distribution of retraction reasons.A comparative study on characteristics of retracted publications across different open access levels Research limitations:There is no exploration of a wider range of OA levels,such as Hybrid OA and Bronze OA.Practical implications:The outcomes of this study suggest the need for increased attention to research integrity within the OA publications.The occurrences offalsification,manipulation,and ethical concerns within Green OA publications warrant attention from the scientific community.Originality/value:This study contributes to the understanding of research integrity in the realm of OA publications,shedding light on retraction patterns and reasons across different OA levels.
基金NSFC(No.71974017)LIS Outstanding Talents Introducing Program,Bureau of Development and Planning of CAS(2022).
文摘Purpose:The notable increase in retraction papers has attracted considerable attention from diverse stakeholders.Various sources are now offering information related to research integrity,including concerns voiced on social media,disclosed lists of paper mills,and retraction notices accessible through journal websites.However,despite the availability of such resources,there remains a lack of a unified platform to consolidate this information,thereby hindering efficient searching and cross-referencing.Thus,it is imperative to develop a comprehensive platform for retracted papers and related concerns.This article aims to introduce“Amend,”a platform designed to integrate information on research integrity from diverse sources.Design/methodology/approach:The Amend platform consolidates concerns and lists of problematic articles sourced from social media platforms(e.g.,PubPeer,For Better Science),retraction notices from journal websites,and citation databases(e.g.,Web of Science,CrossRef).Moreover,Amend includes investigation and punishment announcements released by administrative agencies(e.g.,NSFC,MOE,MOST,CAS).Each related paper is marked and can be traced back to its information source via a provided link.Furthermore,the Amend database incorporates various attributes of retracted articles,including citation topics,funding details,open access status,and more.The reasons for retraction are identified and classified as either academic misconduct or honest errors,with detailed subcategories provided for further clarity.Findings:Within the Amend platform,a total of 32,515 retracted papers indexed in SCI,SSCI,and ESCI between 1980 and 2023 were identified.Of these,26,620(81.87%)were associated with academic misconduct.The retraction rate stands at 6.64 per 10,000 articles.Notably,the retraction rate for non-gold open access articles significantly differs from that for gold open access articles,with this disparity progressively widening over the years.Furthermore,the reasons for retractions have shifted from traditional individual behaviors like falsification,fabrication,plagiarism,and duplication to more organized large-scale fraudulent practices,including Paper Mills,Fake Peer-review,and Artificial Intelligence Generated Content(AIGC).Research limitations:The Amend platform may not fully capture all retracted and concerning papers,thereby impacting its comprehensiveness.Additionally,inaccuracies in retraction notices may lead to errors in tagged reasons.Practical implications:Amend provides an integrated platform for stakeholders to enhance monitoring,analysis,and research on academic misconduct issues.Ultimately,the Amend database can contribute to upholding scientific integrity.Originality/value:This study introduces a globally integrated platform for retracted and concerning papers,along with a preliminary analysis of the evolutionary trends in retracted papers.
文摘One of the most challenging factors affecting impression quality and good marginal fit is the gingival retraction method, which aims to separate the gingiva from the tooth to expose the finishing line of the prepared tooth. Bleeding and contamination from the crevicular fluid may compete for space with the impression material within the sulcus, leading to indistinct preparations and a lack of detail at the margin. In addition, such procedures might damage the PDL and cause permanent recession. Flowable composite cable, as opposed to traditional retraction cords, offers the proper marginal seal and visibility during the impression record because of its lower viscosity, improved adaptability, and elastic properties. The aim of this report is to present a brand-new, innovative method for controlling gingival hemorrhage in addition to the gingival retraction in restorative and prosthodontic treatment by utilizing a flowable composite during the final impression record procedure. In these case reports, the flowable composite cord technique is used instead of traditional gingival cords to modify and refine the gingival tissue before taking the traditional final impression or digital scan. Two cases were done for patients undergoing fixed prosthodontics and veneer treatment within a 2-year follow-up period. In addition, the flowable composite cord was used as temporary restoration before the final prosthetic cementation or under the provisional crowns. As a result, clean and healthy gingival tissues render cementation of the final prosthesis quicker and easier to perform. The patients in both cases claimed that their prosthodontic treatments, which involved the application of a flowable composite cord to temporarily retraction the gingiva, had produced good outcomes at the yearlong follow-up. In conclusion, the flowable composite cord technique is found to be a useful tool to improve the quality of impressions in fixed prosthodontics by providing excellent access for impression material to record fine details of the finish line of the prepared tooth structure, and to alter the inflamed tissue into a healthy tissue.
文摘In this retraction note,we describe the World Journal of Clinical Cases(WJCC)Editorial Office’s decision and reason for retracting an article published in WJCC,volume 12,issue 13.
文摘The authors have decided to retract the article published on World J Gastrointest Oncol(2023)for further consideration due to data errors and some misunderstandings in communication.
文摘Background:Upper eyelid retraction is a challenging complication of cosmetic upper eyelid blepharoplasty.To avoid extra trauma,we developed a new technique for correcting iatrogenic upper eyelid retraction by postmigrating a compound flap of the orbicularis muscle and fascia(OFC)on the anterior surface of the tarsal plate.This method extends the aponeurosis of the levator palpebrae superioris muscle(LPS),which can achieve a good correction for post-blepharoplasty retraction.Methods:We collected data from 15 patients with mild to moderate iatrogenic upper eyelid retraction who were treated at our hospital between February 2017 and December 2019.The OFC was used to replace the missing part of the LPS,and post-migration of the LPS and fixation of the OFC to the tarsal margin were conducted.Postoperative outcome measurements included postoperative binocular symmetry,double eyelid smoothness,eyelid fullness,margin reflex distance(MRD1),degree of eyelid closure,and exposure keratitis.The patients were followed-up at seven days,one month,and six months postoperatively.Results:One patient with moderate eyelid retraction showed undercorrection 6 months postoperatively,with the upper eyelid margin located at the upper edge of the pupil.The remaining patients had the upper eyelid margin stabilized at 1.0–2.0 mm below the upper corneal margin.Other observational indicators were satisfactory,including binocular symmetry,double eyelid fluency,and eyelid fullness.During the follow-up,no exposure keratitis was identified.The MRD1 indexes after the operation were significantly different(P<0.001)from those before the procedure.Conclusions:Extension and post-migration of the LPS using the orbicularis muscle and OFC structure can effectively correct mild iatrogenic eyelid retraction after ptosis with less damage and good postoperative eyelid morphology and closure function.
文摘We have decided to retract the above article because we have concluded that the limitations in our data sample may potentially lead to misinterpretation of the findings.
基金supported by grants from Humanity and Social Science Youth Foundation of Ministry of Education of China (21YJC870016).
文摘Purpose: The number of retracted papers from Chinese university-affiliated hospitals is increasing, which has raised much concern. The aim of this study is to analyze the retracted papers from university-affiliated hospitals in China’s mainland from 2000 to 2021. Design/methodology/approach: Data for 1,031 retracted papers were identified from the Web of Science Core collection database. The information of the hospitals involved was obtained from their official websites. We analyzed the chronological changes, journal distribution, discipline distribution and retraction reasons for the retracted papers. The grade and geographic locations of the hospitals involved were explored as well.Findings: We found a rapid increase in the number of retracted papers, while the retraction time interval is decreasing. The main reasons for retraction are plagiarism/self-plagiarism(n=255), invalid data/images/conclusions(n=212), fake peer review(n=175) and honesty error(n=163). The disciplines are mainly distributed in oncology(n=320), pharmacology & pharmacy(n=198) and research & experimental medicine(n=166). About 43.8% of the retracted papers were from hospitals affiliated with prestigious universities. Research limitations: This study fails to differentiate between retractions due to honest error and retractions due to research misconduct. We believe that there is a fundamental difference between honest error retractions and misconduct retractions. Another limitation is that authors of the retracted papers have not been analyzed in this study.Practical implications: This study provides a reference for addressing research misconduct in Chinese university-affiliated hospitals. It is our recommendation that universities and hospitals should educate all their staff about the basic norms of research integrity, punish authors of scientific misconduct retracted papers, and reform the unreasonable evaluation system.Originality/value: Based on the analysis of retracted papers, this study further analyzes the characteristics of institutions of retracted papers, which may deepen the research on retracted papers and provide a new perspective to understand the retraction phenomenon.
文摘Cancer research is occasionally described as being in a reproducibility crisis.The cancer literature has ample papers retracted due to misconduct,including the use of paper mills,invalid authorship,or fake data.The objective of this paper was to gain an appreciation of the balance of retractions and associated retraction notices of 23 retracted Cancer Biotherapy and Radiopharmaceuticals papers associated with paper mills.By 23 March 2023,these retracted papers had already accumulated 287 citations according to Web of Science Core Collection,253 according to Scopus,and 365 according to Google Scholar,i.e.,metrically speaking,they were highly rewarded.All authors had an affiliation(71%being a hospital)in China.Most(12/21;57%)of corresponding authors had emails with a@163.com suffix.Four of the retraction notices(i.e.,17%)explicitly indicated paper mills as a reason for retraction although,in general,the retraction notices lacked details and background that could assist readers’understanding of the retractions.
基金This study was reviewed and approved by the Medical Ethics Committee of The Affiliated Hospital of Qingdao University(authorisation number:QYFYWZLL26729).
文摘BACKGROUND Mandibular retraction is the main etiological mechanism of class II malocclusion in China and the subsequent distal molar relationship can cause functional discomfort in mastication,breathing and the temporomandibular joint.The use of mandibular advancement(MA)devices has recently emerged as an adolescent mandibular retraction treatment;however,current studies regarding the effect thereof are relatively few,and there is lack of sufficient clinical support.AIM To investigate the clinical effect of invisalign MA on the treatment of mandibular retraction in adolescents.METHODS This study included 30 adolescent patients who underwent treatment with the MA appliances from December 2017 to June 2021.The lateral cephalometric data before and after treatment were collected and imported into Dolphin Imaging software.The changes were measured by linear measurement superimposed with lateral cephalometric trajectory based on the Pancherz technology.RESULTS There was no significant difference in the length and position of maxilla before and after the treatment.The position of the mandible moved 3.13 mm,the length increased 4.14 mm,the mandibular ramus length increased 4.09 mm,the body length increased 4.25 mm,and the position of the condyle moved 1.03 mm forward after treatment.Additionally,changes in the incisor sagittal position and labial inclination were observed.The position of the upper incisor point moved back 1.33 mm,without statistical difference,the inclination and tooth angle decreased by 3.44°and 4.06°,respectively;the position of the lower incisor point was moved 2.98 mm,and the inclination and tooth angle increased by 2.62°and 1.23°,respectively.Furthermore,changes in the incisor overjet and molar relationship were seen.Overjet decreased by 4.31 mm,of which 1.78 mm was due to dental factors,accounting for 41.3%of the effect as opposed to 58.7%due to skeletal factors.Molar relationship improved 3.87 mm,with 1.34 mm due to dental factors,and dental and skeletal factors were accounted for 34.6%and 65.4%of the effect,respectively.CONCLUSION For adolescent patients with mandible retraction,invisalign MA can effectively promote the mandible growth,and it was proven to be mainly due to skeletal effects.
基金the National Key Research and Development Program of China(No.2018YFC1505303).
文摘Casing-while-drilling(CWD)with down the hole(DTH)hammer drilling technology has been widely used in unconsolidated formations,due to its advantages in protecting the borehole wall,excellent rock cuttings capacity,and fast penetration rate in hard rock.As an important component of the CWD system,the structure of the retractable drill bit needs not only to ensure to form stronger reverse circulation,but also to be expandable or retractable as needed,otherwise the drill bit cannot be lift and put down smoothly in the casing,and may lead to drilling accidents.This paper developed a new type of reverse circulation DTH hammer drill bit used for CWD drilling technology.The retractable performance of this type of drill bit is studied using ADAMS software.The results show that it is smoothly expandable and retractable as designed under the conditions of the weight of the bit(WOB)of 0.5–2.0 t and the rotation speed of 30–60 r/min.To investigate the reverse circulation effect of the drill bit,Fluent software was used to simulate the flow characteristic inside it.The simulation results indicated that it can form strong reverse circulation,and the entrainment ratio h can reach 9.5%.