ABSTRACT
BACKGROUND: Physiologic Anchorage Spee's-wire System (PASS) is a new appliance for orthodontic treatment in recent years. It has its superiority in support control, torque domination and friction control, and it is also unique in opening bite. OBJECTIVE: To build a three-dimensional finite element model of PASS with intrusion arch, and to analyze its effects on intrusion of the anterior teeth and on enhancing anchorage of the molars.METHODS: The CT scan data were imported into software of Mimicsl7.0 to obtain a three-dimensional model of the teeth and jaw bone. A series of modeling software such as Geomagic Studio, NX, ANSYSl5.0 were used to obtain the three-dimensional model of the maxillary dentition with PASS and intrusion arch. The overall force of the dentition and movement of the anterior teeth were analyzed when the intrusion arch was located at the mesial side of the central incisor and lateral incisor as well as the distal side of the lateral incisor.RESULTS AND CONCLUSION: It was efficient to accomplish the intrusion of the anterior teeth when the arch was located between central incisors. Labial inclination of the anterior teeth was achieved when the arch was ligated at the mesial side of the lateral incisor. Lingual inclination and intrusion of the anterior teeth was found when the arch was located at the distal side of the lateral incisor. Under these three kinds of conditions, the trend of molar retrodisplacement became remarkable. The maximum movement trend of the incisors was achieved, when the arch was ligated at the mesial side of the central incisor, mainly due to the intrusion of the incisors. The molar retrodisplacement was improved under the three conditions. This experiment simulated the stress distribution and displacement trend of the teeth, which is beneficial to the clinical understanding and application of the PASS technology with intrusion arch.
ABSTRACT
BACKGROUND: Physiologic Anchorage Spee's-wire System (PASS) is a new appliance for orthodontic treatment in recent years. It has its superiority in support control, torque domination and friction control, and it is also unique in opening bite. OBJECTIVE: To build a three-dimensional finite element model of PASS with intrusion arch, and to analyze its effects on intrusion of the anterior teeth and on enhancing anchorage of the molars.METHODS: The CT scan data were imported into software of Mimicsl7.0 to obtain a three-dimensional model of the teeth and jaw bone. A series of modeling software such as Geomagic Studio, NX, ANSYSl5.0 were used to obtain the three-dimensional model of the maxillary dentition with PASS and intrusion arch. The overall force of the dentition and movement of the anterior teeth were analyzed when the intrusion arch was located at the mesial side of the central incisor and lateral incisor as well as the distal side of the lateral incisor.RESULTS AND CONCLUSION: It was efficient to accomplish the intrusion of the anterior teeth when the arch was located between central incisors. Labial inclination of the anterior teeth was achieved when the arch was ligated at the mesial side of the lateral incisor. Lingual inclination and intrusion of the anterior teeth was found when the arch was located at the distal side of the lateral incisor. Under these three kinds of conditions, the trend of molar retrodisplacement became remarkable. The maximum movement trend of the incisors was achieved, when the arch was ligated at the mesial side of the central incisor, mainly due to the intrusion of the incisors. The molar retrodisplacement was improved under the three conditions. This experiment simulated the stress distribution and displacement trend of the teeth, which is beneficial to the clinical understanding and application of the PASS technology with intrusion arch.
ABSTRACT
AIM:To compare the higher-order aberrations between implantations of AcrySof and AcrySof ReStor multifocal aspherical intraocular lens(IOL) with various pupil diameters.METHODS:Fifty-four patients(62 eyes)with bilateral senile cataracts were retrospectively selected.Patients were operated with phacoemulsification and IOL implantation.They were divided into two groups based on the IOL implantation of AcrySof IQ and AcrySof ReStor.Wave front aberration:spherical aberration(C12)and the root mean square of the total higher-order aberration(RMSh)were observed 3 months after surgery.RESULTS:The larger the pupil was, the higher the C12 and RMSh were in the eyes (P<0.01).There were no statistical differences in C12 or RMSh between two groups at 5, 6 or 7mm pupil diameters (P>0.05). CONCLUSION:There are no differences between AcrySof IQ group and AcrySof ReStor group at 5, 6 or 7mm pupil diameters.