Effects on canine intrusion treatment with different Invisalign parameters / 医用生物力学

Objective To study the effects of different parameters (thickness, orthodontic displacement, elastic modulus) of Invisalign on canine displacement and periodontal ligament (PDL) stress during mandibular canine intrusion treatment. Methods Forty-eight different Invisalign models were used to simulate canine intrusion treatment by using the finite element method. Results The initial displacement of the canine and stress on canine PDL were proportional to thickness, intrusion displacement, and elastic modulus of Invisalign. The intrusion displacement had the greatest influence on canine displacement. During canine intrusion treatment, the compressive stress on PDL was the most sensitive parameter and changed easily with the change of parameters. Conclusions The increase of Invisalign thickness, intrusion displacement and elastic modulus can increase canine displacement, however, the stress on PDL also increases, with the largest increasing magnitude in compressive stress on PDL. Therefore, to accelerate tooth movement in Invisalign treatment, it is suggested to use the assisted devices or measurements, such as attachment, supplement of bracket-wires treatment, or implant anchorage.

Effects on canine intrusion treatment with different Invisalign parameters / 医用生物力学

Objective To study the effects of different parameters (thickness,orthodontic displacement,elastic modulus) from Invisalign on canine displacement and periodontal ligament (PDL) stress during mandibular canine intrusion treatment.Methods Forty-eight different Invisalign models were used to simulate canine intrusion treatment by using the finite element method.Results The initial displacement of the canine and stress on canine PDL were proportional to the thickness,intrusion displacement,and elastic modulus of the Invisalign,and the intrusion displacement had the greatest influence on canine displacement.During canine intrusion treatment,the compressive stress on PDL was the most sensitive and changed easily with the change of parameters.Conclusions The canine displacement may increase with the thickness,intrusion displacement and elastic modulus of Invisalign increasing,however,the stress on PDL will also increase,showing the largest increasing magnitude in compressive stress on PDL meanwhile.Therefore,to accelerate tooth movement in Invisalign treatment,it is suggested to use the assisted devices or some other measures such as attachment,supplement of bracket-wires treatment,or implant anchorage.

Effects on canine intrusion treatment with different Invisalign parameters / 医用生物力学

Objective To study the effects of different parameters (thickness,orthodontic displacement,elastic modulus) from Invisalign on canine displacement and periodontal ligament (PDL) stress during mandibular canine intrusion treatment.Methods Forty-eight different Invisalign models were used to simulate canine intrusion treatment by using the finite element method.Results The initial displacement of the canine and stress on canine PDL were proportional to the thickness,intrusion displacement,and elastic modulus of the Invisalign,and the intrusion displacement had the greatest influence on canine displacement.During canine intrusion treatment,the compressive stress on PDL was the most sensitive and changed easily with the change of parameters.Conclusions The canine displacement may increase with the thickness,intrusion displacement and elastic modulus of Invisalign increasing,however,the stress on PDL will also increase,showing the largest increasing magnitude in compressive stress on PDL meanwhile.Therefore,to accelerate tooth movement in Invisalign treatment,it is suggested to use the assisted devices or some other measures such as attachment,supplement of bracket-wires treatment,or implant anchorage.

Verification and evaluation on induction scheme for bodily movement of incisor in children / 医用生物力学

Objective In order to analyze and evaluate the feasibility and effectiveness of induction scheme for bodily movement of incisor in children, the size, orientation and position of the force on tooth surface were estimated and analyzed. Methods The orthodontic jaw from a child was scanned to establish the 3D solid model including mandibular incisor, periodontal ligament and alveolar. Initial strain distributions on outer surface of the periodontal ligament were calculated by software Abaqus, and then the positive strain as the stimulation of the tooth movement was used to simulate the inducted effects from the inducer which was changed twice in succession. Results The rate of orthodontic tooth movement was about 0.27 mm per week, and the total displacement during an induction period was about 1 mm per month, showing it was in accordance with the real inducted effects in clinic. Conclusions The present study proved the feasibility of induction scheme for bodily movement of incisor in children and provided reference for formulation and optimization of induction scheme in clinic.

Mechanical responses from mandibular canine with different movement types in Invisalign treatment / 医用生物力学

Objective To compare mechanical responses from mandibular canine with different movement types in orthodontic treatment with Invisalign. Methods Based on computed tomography images of the teeth and their supporting tissues, the finite element model of the mandible and periodontal ligaments was established. The translation, inclination and rotation movements of the canine in buccolingual direction were simulated to obtain displacements and stresses of the canine and periodontal ligaments under the three different movements. Results The initial movements of the canine and stress distributions on periodontal ligaments were mainly determined by different movement types of the canine. The stress distributions on periodontal ligaments were similar when the canine was in translation and inclination movements. The bodily movement trend of the canine was much larger in rotation movement than that in translation movement under the same displacement magnitude. Conclusions The mechanical responses and its degrees from canine would be different under different movement types. To get better understanding with such different responses can help design more reasonable orthodontic treatment with Invisalign, avoid the damage to periodontium and achieve the orthodontic treatment with less time.