Three dimensional analysis of tooth movement using different sizes of NiTi wire on NiTi scissors-bite corrector / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to compare the difference in three dimensional tooth movement using three different wire sizes (0.018 x 0.025-in, 0.016 x 0.022-in, 0.016-in) on a NiTi scissors-bite corrector. METHODS: Computed tomography (CT) images of the experimental model before and after tooth movement were taken and reconstructed into three dimensional models for superimposition. The direction and the amount of tooth movement were measured and analyzed statistically. RESULTS: The lingual and intrusive movements of the crown of the maxillary second molar were increased as the size of the NiTi wire increased. The roots of the maxillary second molars moved buccally except for the 0.016-in group. The intrusive movement of the roots of the maxillary second molars was increased as the size of the NiTi wire increased. Due to the use of orthodontic mini-implants, anchorage loss was under 0.2 mm on average. CONCLUSIONS: The 0.018 x 0.025-in NiTi wire was most effective in lingual and intrusive movement of the maxillary second molar which was in scissors-bite position. Indirect skeletal anchorage with a single orthodontic mini-implant was rigid enough to prevent anchorage loss.

Three dimensional analysis of tooth movement using different types of maxillary molar distalization appliances / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to compare the three dimensional changes of tooth movement using four different types of maxillary molar distalization appliances; pendulum appliance (PD), mini-implant supported pendulum appliance (MPD), stainless steel open coil spring (SP) and mini-implant supported stainless steel open coil spring (MSP). METHODS: These experiments were performed using the Calorific machine? which can simulate dynamic tooth movement. Computed tomography (CT) images of the experimental model were taken before and after tooth movement in 1 mm thicknesses and reconstructed into a three dimensional model using V-works 4.0TM. These reconstructed images were superimposed using Rapidform 2004TM and the direction and amount of tooth movement were measured. RESULTS: The mean reciprocal anchor loss ratio at the first premolar was 17 - 19% for the PD and SP groups. The appliances using mini-implants (MPD or MSP) resulted in less anchorage loss (7 - 8%). On application of a pendulum appliance or MPD, distalization was obtained by tipping rather than by bodily movement. Furthermore, the maxillary second molar tipped distally and bucally. But on application of MSP, distalization was achieved almost by bodily movement. CONCLUSIONS: Regarding tooth movement patterns during molar distalization, stainless steel open coil spring with indirect skeletal anchorage was relatively superior to other methods.

An experimental study on the dynamic tooth movement of two molar uprighting spring by calorific machine / 대한치과교정학회지

The aim of this investigation was to evaluate the differences of two canti-lever springs by using a new simulation system. This was done using a Calorific machine that compared crown uprighting spring and root uprighting spring. The Calorific machine was designed to allow observation of the whole process of tooth moving, and it composed of three parts(a temperature regulation system, electro-thermodynamic teeth, and an artificial alveolar bone component). The obtained results wee as follows. 1. Distal and buccal movement of the anchor teeth were observed greater in the root uprighting spring than the crown uprighting spring. 2. Crown uprighting spring showed distal movement of the crown of lower second molar for 3.29mm but root uprighting spring showed only 1.68mm. 3. Crown uprighting spring exhibited forward movement of mesial and distal root of the lower second molar for 3.91mm, 3.60mm but the root uprighting spring showed 6.76mm, 6.26 mm.