Simple and effective method for treating severe adult skeletal class II malocclusion: A case report

BACKGROUND Severe skeletal class II malocclusion is the indication for combined orthodontic and orthognathic treatment.CASE SUMMARY A woman with a chief complaint of a protruding chin and an inability to close her lips requested orthodontic camouflage.The treatment plan consisted of extracting the right upper third molar,right lower third molar,left lower second molar,and left upper third molar and moving the maxillary dentition distally using a convenient method involving microimplant nail anchors,push springs,long arm traction hooks,and elastic traction chains.After 52 months of treatment,her overbite and overjet were normal,and her facial profile was favorable.CONCLUSION This method can be used for distal movement of the maxillary dentition and to correct severe skeletal class II malocclusion in adults.

Assessment of cortical bone microdamage following insertion of microimplants using optical coherence tomography: a preliminary study

Objectives： The study was done to evaluate the efficacy of optical coherence tomography （OCT）, to detect and analyze the microdamage occurring around the microimplant immediately following its placement, and to compare the findings with micro-computed tomography （IJCT） images of the samples to validate the result of the present study. Methods： Microimplants were inserted into bovine bone samples. Images of the samples were obtained using OCT and μCT. Visual comparisons of the images were made to evaluate whether anatomical details and microdamage induced by microimplant insertion were accurately revealed by OCT. Results： The surface of the cortical bone with its anatomical variations is visualized on the OCT images. Microdamage occurring on the surface of the cortical bone around the microimplant can be appreciated in OCT images. The resulting OCT images were compared with the μCT images. A high correlation regarding the visualization of individual microcracks was observed. The depth penetration of OCT is limited when compared to μCT. Conclusions： OCT in the present study was able to generate high-resolution images of the microdamage occurring around the microimplant. Image quality at the surface of the cortical bone is above par when compared with μCT imaging, because of the inherent high contrast and high-resolution quality of OCT systems. Improvements in the imaging depth and development of intraoral sensors are vital for developing a real-time imaging system and integrating the system into orthodontic practice.

Surface characteristics and mechanical behavior of retrieved orthodontic microimplants

Objectives： To observe the surface characteristics and mechanical behavior of retrieved microimplants under clinically simulating experimental conditions and to investigate the feasibility of rouse of microimplants. Materials and methods： The microimplants, inserted at different angles, were retrieved from the patients （RMIP） and the artificial bone （RMIA）. Surface characteristics, including morphologic changes of tips and thread edges, length reduction, and surface compositional variation, were evaluated using a field emission scanning electron microscope, a stereoscopic microscope, and energy-dispersive X-ray spectroscopy, respectively. Mechanical behavior comprising maximum insertion torque （MIT） and insertion time was tested with the artificial bone under clinically simulating conditions. Results： The tips and thread edges were worn out to various degrees in retrieved microimplants and thin deposits were observed on the surface in the RMIP group. Traces of foreign elements, such as iron, sulphur, and calcium, were detected on the surface of RMIP. Both MIT and insertion time of retrieved microimplants were increased compared to their initial use, and were much greater in RMIP. The increases of MIT were seen in all groups inserted at the insertion angle of 45~ compared with 90~, although the differences were not statistically significant. Conclusions： Retrieved microimplants exhibited different degrees of changes on surface characteristics and mechanical behavior, with more changes in RMIP. The reuse of microimplants for immediate relocation in the same patient may be acceptable; however, postponed relocation and allogeneic reuse of microimplants are not recommended in clinical practice.