Estimating the location of the center of resistance of canines

Abstract

Objective: To develop a method to quickly estimate the location of center of resistance (CR) in mesial-distal (MD) and buccal-lingual (BL) directions from the tooth's image. Materials and Methods: The maxillary cone-beam computed tomography (CBCT) scans of 18 patients were used. Finite element (FE) models of the canines and their surrounding tissues were built based on their CBCT scans to calculate the locations of CR. Root length, centroid of the contact surface (CCS), and centroid of projection of the contact surface (CPCS) were also obtained from the images. The CCS and CPCS locations were projected on the tooth's long axis, which were represented as percentages of the root length measured from the root's apex. Results: Using the FE results as the standards, the errors of using CCS or CPCS to estimate CR were calculated. The average location of CR calculated using the FE method was 60.2% measured from the root's apex in the MD direction and 58.4% in the BL direction. The location of the CCS was 60.9%. The difference in CR was 0.7% in the MD direction and 2.5% in the BL direction. The location of CPCS was 60.2% in the MD direction and 59.1% in the BL direction, which resulted in a 0.1% and 0.8% difference with the reference CR, respectively. The average difference of CR in the MD and BL directions was small but statistically significant (P , .05). Conclusion: The locations of the CR of a human canine in the MD and BL directions can be estimated by finding the CPCSs in those directions. (Angle Orthod. 2016;86:365-371.)

Assessment of automatic segmentation of teeth using a watershed-based method

“…18 It also allows the remaining intraosseous tooth volume to be calculated and the behaviour of the centre of resistance of the tooth to be better predicted. 19 In implantology, the segmented bone volume or segmented sinus volume makes it possible to predict the dose and even to machine the exact volume of bio-material intended to reconstitute the bone volume in pre-implant. 20 The volume segmented can also be used to mimic the transgingival root volume to obtain an optimal implant prosthetic abutment.…”

The Effects of Corticotomy and Piezocision in Orthodontic Canine Retraction

“…For applying the force which is closer to the center of resistance of the tooth, canine teeth play an important role. [ 13 ] In order to achieve great inclination, the force is directly applied on the canine brackets. This force application is also helpful in increasing the tooth movement rate and less movement of the associated body as well.…”

“…This force application is also helpful in increasing the tooth movement rate and less movement of the associated body as well. [ 13 ]…”

Mechanical responses of maxillary canine and surrounding tissues under orthodontic loading: a non-linear three-dimensional finite element analysis

“…The stress decreases through the apex since the center of rotation (CRot) is located near the apex. According to the results, as the area of force application gets closer to the cervical section, the force gets closer to the center of the resistance (CRes) of the tooth [64,[80][81][82][83]. Consequently, the stress distribution in the tooth becomes more uniform and the rotation movement reduces.…”