Rapid technological improvements in biomaterials,computer-aided design(CAD)and manufacturing(CAM)have endorsed clear aligner therapy(CAT)as a mainstay of orthodontic treatment,and the materials employed for aligner fa...Rapid technological improvements in biomaterials,computer-aided design(CAD)and manufacturing(CAM)have endorsed clear aligner therapy(CAT)as a mainstay of orthodontic treatment,and the materials employed for aligner fabrication play an all-important role in determining the clinical performance of clear aligners.This narrative review has attempted to comprehensively encompass the entire gamut of materials currently used for the fabrication of clear aligners and elucidate their characteristics that are crucial in determining their performance in an oral environment.Historical developments and current protocols in aligner fabrication,features of contemporary bioactive materials,and emerging trends related to CAT are discussed.Advances in aligner material chemistry and engineering possess the potential to bring about radical transformations in the therapeutic applications of CAT;in the absence of which,clear aligners would continue to underperform clinically,due to their inherent biomechanical constraints.Finally,while innovations in aligner materials such as shape memory polymers,direct three-dimensional(3D)printed clear aligners and bioactive materials combined with clear aligner materials are essential to further advance the applications of CAT;increased awareness of environmental responsibilities among aligner manufacturers,aligner prescribing clinicians and aligner users is essential for better alignment of our climate change goals towards a sustainable planet.展开更多
This study aimed to explore the optimal invisible orthodontic force system during the en-mass distalization of two maxillary molars to minimize the side effect of anchorage loss by changing the direction of the applic...This study aimed to explore the optimal invisible orthodontic force system during the en-mass distalization of two maxillary molars to minimize the side effect of anchorage loss by changing the direction of the application of the orthodontic force system.A high bio-fidelity 3D finite element model including maxilla,periodontal ligament,dentition,clear aligner,3D anchorage attachment and mini-implant was established.Different lengths of lateral hooks of 3D-printed anchorage attachments and mini-implant positions into the palatal alveolus were considered.A 200 g distal force was applied to the lateral hooks of different horizontal lengths(3.26 mm,6.52 mm and 9.78 mm)with the mini-implant as the application point.Using ABAQUS software,orthodontic tooth movements under 12 different clinical treatment designs were analyzed and calculated.The 3D anchorage attachment enhanced the anchorage of anterior teeth and alleviated the tipping/extrusion of premolars.In contrast to without clear aligners,length of the lateral hook had a negligible effect on both mesial tipping and buccal tipping with clear aligners,which could then be ignored.The change in mesial tipping was less and nearly remained constant despite of the different heights of the mini-implant.The 3D anchorage attachment assisted clear aligner can avoid the side effects of anterior tooth proclination caused by insufficient anchorage.The length of the lateral hook,and height of the mini-implant in this invisible orthodontic force system hardly affects the tooth movement of anchorage units.Clear aligners can effectively control the rotation and tipping of anchorage units caused by 3D anchorage attachment.展开更多
This study was aimed at analysing the mechanical characteristics of different mandibular extraction modes using a clear aligner.Three experimental schemes of different extraction patterns were designed to treat mandib...This study was aimed at analysing the mechanical characteristics of different mandibular extraction modes using a clear aligner.Three experimental schemes of different extraction patterns were designed to treat mandibular crowding,including extraction of one mandibular central incisor,bilateral first premolars,and bilateral second premolars.The stress distribution during the space closing was analysed using the finite element method.When a central incisor was extracted,a significant retraction force was found in the anterior region,in line with the design expectation.The posterior teeth,which were designed to move mesially,acted as anchorage for anterior retraction,and were subjected to a mesial force.The anterior teeth were retracted when the bilateral first premolars were extracted.The lateral incisors and canines were subjected to a significant distal force and moment,while the central incisors and canines were subjected to lingual forces and moments.Additionally,the canines were subjected to a non-designated intruding force.The molars were designed to move mesially when the bilateral second premolars were extracted.All molars were subjected to a significant mesial force,while the lingual force on the front teeth was slight.The bilateral second molars were subjected to non-design mesial moment and extrusive force.The bilateral first molars were subjected to a non-designated mesial moment,and the bilateral first premolars on both sides were subjected to non-designated intrusive force and distal moment.When one incisor was extracted,attachments on the anterior teeth had a controlling effect on the tooth axis,but the anterior teeth still tended to tilt.When the bilateral first premolars were extracted,the anterior teeth showed a tendency for lingual inclination.The risk of distal inclination of the canines and lingual inclination of the central incisor increased.When the bilateral second premolars were extracted and the posterior teeth were designed to move mesially,the teeth on both sides of the extraction sites showed an obvious bowing effect.展开更多
The malalignment of teeth is treated classically by metal braces with alloy wires,which has an unfavorable influence on the patients appearance during the treatment.With the development of digitization,computer simula...The malalignment of teeth is treated classically by metal braces with alloy wires,which has an unfavorable influence on the patients appearance during the treatment.With the development of digitization,computer simulation and three-dimensional(3D)printing technology,herein,a modern treatment was tried using clear polymeric aligners,which were fabricated by molding polyurethane films via thermoforming on the 3D-printed personalized dental models.The key parameters of photocurable 3D printing of dental models and the mechanical properties of the clear aligner film material were examined.The precision of a 3D-printed dental model mainly relied on characteristics of photocurable resin,the resolution of light source and the exposure condition,which determined the eventual shape of the molded clear aligner and thus the orthodontic treatment efficacy.The biocompatibility of the polyurethane filmmaterial was confirmed through cytotoxicity and hemolysis tests in vitro.Following a series of 3D-printed personalized dental models and finite element analysis to predict and plan the fabrication and orthodontic processes,corresponding clear aligners were fabricated and applied in animal experiments,which proved the efficacy and biocompatibility in vivo.Clinical treatments of 120 orthodontic cases were finally carried out with success,which highlights the advantage of the clear aligners as an esthetic,compatible and efficient appliance.展开更多
文摘Rapid technological improvements in biomaterials,computer-aided design(CAD)and manufacturing(CAM)have endorsed clear aligner therapy(CAT)as a mainstay of orthodontic treatment,and the materials employed for aligner fabrication play an all-important role in determining the clinical performance of clear aligners.This narrative review has attempted to comprehensively encompass the entire gamut of materials currently used for the fabrication of clear aligners and elucidate their characteristics that are crucial in determining their performance in an oral environment.Historical developments and current protocols in aligner fabrication,features of contemporary bioactive materials,and emerging trends related to CAT are discussed.Advances in aligner material chemistry and engineering possess the potential to bring about radical transformations in the therapeutic applications of CAT;in the absence of which,clear aligners would continue to underperform clinically,due to their inherent biomechanical constraints.Finally,while innovations in aligner materials such as shape memory polymers,direct three-dimensional(3D)printed clear aligners and bioactive materials combined with clear aligner materials are essential to further advance the applications of CAT;increased awareness of environmental responsibilities among aligner manufacturers,aligner prescribing clinicians and aligner users is essential for better alignment of our climate change goals towards a sustainable planet.
基金This work was supported by the National Natural Science Foundation of China(Grant No.12072055,11872135,U20A20390,U22A20314)Natural Science Foundation of Beijing(Grant No.L212063)+3 种基金the Fundamental Research Funds for the Central Universities,the 111 Project(No.B13003)the National Research Program of China(Grant No.2022YFC2504200)Orthodontic research project of youth clinical research fund of Chinese Stomatological Association(Grant No.CSA-O2020-07)Municipal graduate tutor team construction project(dstd201903).
文摘This study aimed to explore the optimal invisible orthodontic force system during the en-mass distalization of two maxillary molars to minimize the side effect of anchorage loss by changing the direction of the application of the orthodontic force system.A high bio-fidelity 3D finite element model including maxilla,periodontal ligament,dentition,clear aligner,3D anchorage attachment and mini-implant was established.Different lengths of lateral hooks of 3D-printed anchorage attachments and mini-implant positions into the palatal alveolus were considered.A 200 g distal force was applied to the lateral hooks of different horizontal lengths(3.26 mm,6.52 mm and 9.78 mm)with the mini-implant as the application point.Using ABAQUS software,orthodontic tooth movements under 12 different clinical treatment designs were analyzed and calculated.The 3D anchorage attachment enhanced the anchorage of anterior teeth and alleviated the tipping/extrusion of premolars.In contrast to without clear aligners,length of the lateral hook had a negligible effect on both mesial tipping and buccal tipping with clear aligners,which could then be ignored.The change in mesial tipping was less and nearly remained constant despite of the different heights of the mini-implant.The 3D anchorage attachment assisted clear aligner can avoid the side effects of anterior tooth proclination caused by insufficient anchorage.The length of the lateral hook,and height of the mini-implant in this invisible orthodontic force system hardly affects the tooth movement of anchorage units.Clear aligners can effectively control the rotation and tipping of anchorage units caused by 3D anchorage attachment.
基金the Clinical Research Program of Ninth People’s Hospital affiliated to Shanghai Jiao Tong University School of Medicine(No.JYLJ-10)。
文摘This study was aimed at analysing the mechanical characteristics of different mandibular extraction modes using a clear aligner.Three experimental schemes of different extraction patterns were designed to treat mandibular crowding,including extraction of one mandibular central incisor,bilateral first premolars,and bilateral second premolars.The stress distribution during the space closing was analysed using the finite element method.When a central incisor was extracted,a significant retraction force was found in the anterior region,in line with the design expectation.The posterior teeth,which were designed to move mesially,acted as anchorage for anterior retraction,and were subjected to a mesial force.The anterior teeth were retracted when the bilateral first premolars were extracted.The lateral incisors and canines were subjected to a significant distal force and moment,while the central incisors and canines were subjected to lingual forces and moments.Additionally,the canines were subjected to a non-designated intruding force.The molars were designed to move mesially when the bilateral second premolars were extracted.All molars were subjected to a significant mesial force,while the lingual force on the front teeth was slight.The bilateral second molars were subjected to non-design mesial moment and extrusive force.The bilateral first molars were subjected to a non-designated mesial moment,and the bilateral first premolars on both sides were subjected to non-designated intrusive force and distal moment.When one incisor was extracted,attachments on the anterior teeth had a controlling effect on the tooth axis,but the anterior teeth still tended to tilt.When the bilateral first premolars were extracted,the anterior teeth showed a tendency for lingual inclination.The risk of distal inclination of the canines and lingual inclination of the central incisor increased.When the bilateral second premolars were extracted and the posterior teeth were designed to move mesially,the teeth on both sides of the extraction sites showed an obvious bowing effect.
基金supports from NSF of China(grants No.52130302,21961160721)National Key R&D Program of China(grant No.2016YFC1100300)。
文摘The malalignment of teeth is treated classically by metal braces with alloy wires,which has an unfavorable influence on the patients appearance during the treatment.With the development of digitization,computer simulation and three-dimensional(3D)printing technology,herein,a modern treatment was tried using clear polymeric aligners,which were fabricated by molding polyurethane films via thermoforming on the 3D-printed personalized dental models.The key parameters of photocurable 3D printing of dental models and the mechanical properties of the clear aligner film material were examined.The precision of a 3D-printed dental model mainly relied on characteristics of photocurable resin,the resolution of light source and the exposure condition,which determined the eventual shape of the molded clear aligner and thus the orthodontic treatment efficacy.The biocompatibility of the polyurethane filmmaterial was confirmed through cytotoxicity and hemolysis tests in vitro.Following a series of 3D-printed personalized dental models and finite element analysis to predict and plan the fabrication and orthodontic processes,corresponding clear aligners were fabricated and applied in animal experiments,which proved the efficacy and biocompatibility in vivo.Clinical treatments of 120 orthodontic cases were finally carried out with success,which highlights the advantage of the clear aligners as an esthetic,compatible and efficient appliance.
