BACKGROUND Invaginated teeth pose greater challenges in clinical management because of their complex configuration.With advancements in equipment and materials,such as the dental operation microscope,cone-beam compute...BACKGROUND Invaginated teeth pose greater challenges in clinical management because of their complex configuration.With advancements in equipment and materials,such as the dental operation microscope,cone-beam computed tomography and mineral trioxide aggregate,the preservation rate of type Ⅲ dens invaginatus could be greatly increased.CASE SUMMARY This case report presented a 31-year-old woman with complaints of spontaneous swelling and pain in the right maxillary lateral tooth.With the aid of cone-beam computed tomography,type Ⅲ dens invaginatus with apical periodontitis was diagnosed and confirmed.Three-visit endodontic treatment was performed.In the first visit,the invagination was carefully removed under the dental operation microscope,and chemomechanical preparation was done.In the second visit,mineral trioxide aggregate apical barrier surgery was performed in this tooth.In the third visit,the canal was finally obturated with thermoplastic gutta-percha to recover the crown morphology.A 26-mo follow-up revealed a satisfied outcome both in the radiographic and oral examinations.CONCLUSION In this case,removal of the entire abnormal structure provided great convenience for the follow-up treatment.When confronted with the same clinical case in the future,we can take a similar approach to address it.展开更多
To date,sustainable thermosetting polymers and their composites have emerged to address recyclability issues.However,achieving mild degradation of these polymers compromises their comprehensive properties such as flam...To date,sustainable thermosetting polymers and their composites have emerged to address recyclability issues.However,achieving mild degradation of these polymers compromises their comprehensive properties such as flame retardancy and glass transition temperature(T_(g)).Moreover,the reuse of degradation products after recycling for upcycling remains a significant challenge.This study introduces phosphorus-containing anhydride into tetraglycidyl methylene diphenylamine via a facile anhydride-epoxy curing equilibrium with triethanolamine as a transesterification modifier to successfully prepare flame-retardant,malleable,reprocessable,and easily hydrothermally degradable epoxy vitrimers and recyclable carbon fiber-reinforced epoxy composites(CFRECs).The composite exhibited excellent flame retardancy and a high Tg of 192℃,while the presence of stoichiometric primary hydroxyl groups along the ester-bonding crosslinks enabled environmentally friendly degradation(in H_(2)O)at 200℃without any external catalyst.Under mild degradation conditions,the fibers of the composite material were successfully recycled without being damaged,and the degradation products were reused to create a recyclable adhesive with a peel strength of 3.5 MPa.This work presents a method to produce flame retardants and sustainable CFRECs for maximizing the value of degradation products,offering a new upcycling method for high-end applications.展开更多
基金the Priority Academic Program Development of Jiangsu Higher Education Institutions,No.PAPD2018-87.
文摘BACKGROUND Invaginated teeth pose greater challenges in clinical management because of their complex configuration.With advancements in equipment and materials,such as the dental operation microscope,cone-beam computed tomography and mineral trioxide aggregate,the preservation rate of type Ⅲ dens invaginatus could be greatly increased.CASE SUMMARY This case report presented a 31-year-old woman with complaints of spontaneous swelling and pain in the right maxillary lateral tooth.With the aid of cone-beam computed tomography,type Ⅲ dens invaginatus with apical periodontitis was diagnosed and confirmed.Three-visit endodontic treatment was performed.In the first visit,the invagination was carefully removed under the dental operation microscope,and chemomechanical preparation was done.In the second visit,mineral trioxide aggregate apical barrier surgery was performed in this tooth.In the third visit,the canal was finally obturated with thermoplastic gutta-percha to recover the crown morphology.A 26-mo follow-up revealed a satisfied outcome both in the radiographic and oral examinations.CONCLUSION In this case,removal of the entire abnormal structure provided great convenience for the follow-up treatment.When confronted with the same clinical case in the future,we can take a similar approach to address it.
基金Financial supports by the National Key Research and Development Program of China(Grant No.2021YFB3700201)the National Science Foundation of China(Grant Nos.21975166,51991351,51991350)+1 种基金the 111 Project(Grant No.B20001)the Fundamental Research Funds for the Central Universities are sincerely acknowledged.
文摘To date,sustainable thermosetting polymers and their composites have emerged to address recyclability issues.However,achieving mild degradation of these polymers compromises their comprehensive properties such as flame retardancy and glass transition temperature(T_(g)).Moreover,the reuse of degradation products after recycling for upcycling remains a significant challenge.This study introduces phosphorus-containing anhydride into tetraglycidyl methylene diphenylamine via a facile anhydride-epoxy curing equilibrium with triethanolamine as a transesterification modifier to successfully prepare flame-retardant,malleable,reprocessable,and easily hydrothermally degradable epoxy vitrimers and recyclable carbon fiber-reinforced epoxy composites(CFRECs).The composite exhibited excellent flame retardancy and a high Tg of 192℃,while the presence of stoichiometric primary hydroxyl groups along the ester-bonding crosslinks enabled environmentally friendly degradation(in H_(2)O)at 200℃without any external catalyst.Under mild degradation conditions,the fibers of the composite material were successfully recycled without being damaged,and the degradation products were reused to create a recyclable adhesive with a peel strength of 3.5 MPa.This work presents a method to produce flame retardants and sustainable CFRECs for maximizing the value of degradation products,offering a new upcycling method for high-end applications.
