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Purpose: Smokers who receive orthodontic treatment occasionally require longer treatment periods. Nevertheless, it is unclear whether delayed tooth movement can be recovered by encouraging smoking cessation. The study was designed to examine whether tooth movement rates can be recovered by a period of smoking cessation in rats treated with a comprehensive mixture of tobacco smoke components (TSCs). Materials and methods: Nine-week-old Wistar male rats were divided into no treatment, sham, TSCs, and TSCs cessation groups. The rats in the no treatment and sham groups drank distilled water, whereas those in the TSCs group and the TSCs cessation groups received TSCs in their drinking water. A smoking cessation period of 10 days was set for rats in the TSCs cessation group before the three groups underwent tooth movement. Tooth movement distance was measured using micro-computed tomography, and osteoclast differentiation was evaluated histologically. Results: There was significantly greater tooth movement in the sham and TSCs cessation groups than in the TSCs group. However, the TSCs cessation group showed lesser osteoclast differentiation than the sham group. Conclusion: Our results indicate that delayed tooth movement caused by smoking was recovered by smoking cessation treatment; this recovery seems to be partially due to the increase in osteoclasts, although the number of osteoclasts was still less than that in the sham group. [ABSTRACT FROM AUTHOR]

Orthodontists use a self-etching adhesive system when attaching brackets, to enamel. The purpose of this study was to evaluate the erosion effects of common clinically used adhesive systems on human enamel surfaces by atomic force microscopy (AFM). Four commercially available adhesive systems (i.e., Kurasper F, Beauty Ortho Bond, Orthophic LC, and Transbond XT) were applied to ground enamel surfaces of extracted human teeth. Enamel surface roughness (ESR), absolute depth profile (ADP), and surface hardness were evaluated by AFM. The ESR and ADP were significantly higher after the pretreatment with the phosphoric acid-etching adhesive system than after the pretreatments with the three self-etching adhesive systems. The surface nanohardness decreased after the pretreatment with the phosphoric acid-etching adhesive system but increased after the pretreatments with the self-etching adhesive systems. These results suggest that the use of a self-etching primer for enamel conditioning might prevent decalcification caused by phosphoric acid etching. [ABSTRACT FROM AUTHOR]

Purpose: To perform vertical bone augmentation on rat parietal bone by coating the inner surface of dense polytetrafluoroethylene (d-PTFE) domes with hydroxyapatite (HA) using Erbium Yttrium Aluminum Garnet (Er:YAG) pulsed laser deposition in a rat model., Methods: The d-PTFE plate surface, α-tricalcium phosphate (α-TCP) coating, and HA coating were measured using scanning electron microscopy and X-ray diffraction to confirm the replacement of α-TCP with HA via high-pressure steam sterilization. The dome was glued to the center of the rat parietal bone and closed with periosteal and epithelial sutures. The rats were euthanized at 4, 8, and 12 weeks postoperatively, and the d-PTFE dome and surrounding tissues were harvested for radiological and histological evaluation., Results: In a group without HA coating (control group), a small amount of layered neosteum was observed in the d-PTFE dome. Conversely, a new balloon-shaped bone was observed in a HA-coated group (experimental group). Bone growth and number of bone beams were higher in the HA-coated group from 4 to 12 weeks postoperatively than those in the control group. However, no significant differences in bone mineral density values or bone bridge widths were observed., Conclusions: The HA coating enhanced bone augmentation without bone replacement. Histological findings indicated that the new bone comprised normal bone tissue with cartilage lumen and matrix. Therefore, our results indicate that bone augmentation with a HA coating may be mediated by endochondral ossification, a process similar to that of ectopic ossification.