Orthodontic biomechanics,through the integration of multiple disciplines,has made significant advancements in understanding tooth movement mechanisms,optimizing orthodontic techniques,and providing personalized treatment.Research indicates that three-dimensional finite element models accurately reveal the dynamic relationship between the stress distribution in periodontal tissues and bone remodeling,highlighting the critical role of light force control in ensuring treatment safety.Clear aligners,through low-friction elastic handle(LFEH),collaborative anchorage strategies,and material mechanics optimization,significantly enhance the predictability of tooth movement,with LFEH design reducing lingual and buccal tilting stresses.The application of biologically active materials and smart archwires has significantly enhanced enamel resistance to demineralization and sustained light force release.Artificial intelligence technology is deeply integrated into the entire treatment process:dynamic prediction models based on deep learning optimize force application schemes,while real-time mechanical monitoring systems dynamically calibrate movement paths,promoting the precision of treatment.However,individual differences in biomechanical responses and complex movements remain key challenges.Future efforts should focus on integrating multimodal data to build intelligent diagnostic systems,developing mechanically responsive biomaterials and degradable anchorage devices,and deepening research on molecular-cell-tissue cross-scale mechanisms to achieve a leap from'force-oriented'to'biological response-oriented'precision orthodontics.

Objective To compare the differences in thickness and fitting accuracy between direct-printed aligners(DPA)and conventional thermoformed aligners(TFA),and to provide experimental evidence for the clinical application of clear aligners(CAs).Methods Sixteen adult subjects with mild dental crowding and no significant caries or restorations were recruited.For each subject,CAs were fabricated using direct three-dimensional(3D)printing and conventional thermoforming methods.The CA thickness was measured at the labial/buccal and lingual surfaces of incisors,canines,and first molars using a high-precision electronic thickness gauge.Micro-CT scanning was employed to analyze the gap between the CAs and dental models,followed by statistical analyses.Results The overall mean thickness of the DPA group was(0.60±0.04)mm,significantly higher than that of the TFA group(0.48±0.06)mm(P＜0.000 1),with superior thickness uniformity.The average gap between CAs and dental models in the DPA group was(0.29±0.08)mm,significantly smaller than that in the TFA group(0.31±0.16)mm(P＜0.05),particularly at the incisal edges of incisors,buccal surfaces of canines,and occlusal surfaces of first molars.Conclusions Compared to conventional TFA,DPA demonstrates significant advantages in thickness uniformity and fitting accuracy,indicating that DPA has greater application potential in orthodontic clinical treatment.

Orthodontic biomechanics,through the integration of multiple disciplines,has made significant advancements in understanding tooth movement mechanisms,optimizing orthodontic techniques,and providing personalized treatment.Research indicates that three-dimensional finite element models accurately reveal the dynamic relationship between the stress distribution in periodontal tissues and bone remodeling,highlighting the critical role of light force control in ensuring treatment safety.Clear aligners,through low-friction elastic handle(LFEH),collaborative anchorage strategies,and material mechanics optimization,significantly enhance the predictability of tooth movement,with LFEH design reducing lingual and buccal tilting stresses.The application of biologically active materials and smart archwires has significantly enhanced enamel resistance to demineralization and sustained light force release.Artificial intelligence technology is deeply integrated into the entire treatment process:dynamic prediction models based on deep learning optimize force application schemes,while real-time mechanical monitoring systems dynamically calibrate movement paths,promoting the precision of treatment.However,individual differences in biomechanical responses and complex movements remain key challenges.Future efforts should focus on integrating multimodal data to build intelligent diagnostic systems,developing mechanically responsive biomaterials and degradable anchorage devices,and deepening research on molecular-cell-tissue cross-scale mechanisms to achieve a leap from'force-oriented'to'biological response-oriented'precision orthodontics.

Objective To compare the differences in thickness and fitting accuracy between direct-printed aligners(DPA)and conventional thermoformed aligners(TFA),and to provide experimental evidence for the clinical application of clear aligners(CAs).Methods Sixteen adult subjects with mild dental crowding and no significant caries or restorations were recruited.For each subject,CAs were fabricated using direct three-dimensional(3D)printing and conventional thermoforming methods.The CA thickness was measured at the labial/buccal and lingual surfaces of incisors,canines,and first molars using a high-precision electronic thickness gauge.Micro-CT scanning was employed to analyze the gap between the CAs and dental models,followed by statistical analyses.Results The overall mean thickness of the DPA group was(0.60±0.04)mm,significantly higher than that of the TFA group(0.48±0.06)mm(P＜0.000 1),with superior thickness uniformity.The average gap between CAs and dental models in the DPA group was(0.29±0.08)mm,significantly smaller than that in the TFA group(0.31±0.16)mm(P＜0.05),particularly at the incisal edges of incisors,buccal surfaces of canines,and occlusal surfaces of first molars.Conclusions Compared to conventional TFA,DPA demonstrates significant advantages in thickness uniformity and fitting accuracy,indicating that DPA has greater application potential in orthodontic clinical treatment.

国家自然科学基金项目(11932012、81400536),上海申康医院发展中心临床创新三年行动计划(SHDC2020CR3009A),上海交通大学医工(理)交叉基金(JYJC202130)