Horizontal augmentation through the ridge-split procedure: a predictable surgical modality in implant reconstruction.

Among alveolar ridge augmentation techniques, the ridge-split procedure demonstrates many benefits, including no need for a second (donor) surgical site, rare risk of inferior alveolar nerve injury, and less pain and swelling, and others. Lateral bone augmentation through the ridge-split works best in a localized lateral bony defect intended for 1 or 2 implants and where the ridge is vertically intact. In this article, the authors present a detailed description of the implant-driven technique of alveolar ridge-split procedure in small and large bone deficiencies, in maxilla and mandible, supplemented by multiple photographs. The authors emphasize the need for careful manipulation of the thin ridge based on knowledge of precise surgical principles and stress that a practitioner needs specialized training and experience to perform this type of alveolar bone augmentation.

Effects of traditional Chinese medicine on bone remodeling during orthodontic tooth movement.

ETHNOPHARMACOLOGICAL RELEVANCE: Dipsacus asper Wall (Dipsacaceae), Salvia miltiorrhiza (Salvia) and Drynaria fortunei (Drynaria) have been traditionally used in Chinese medicine as the main ingredient of many formulations for the treatment of cardiovascular and inflammatory diseases. AIM OF THE STUDY: This study was aimed to evaluate the effect of the traditional Chinese medicine (TCM) Dipsacaceae, Salvia and Drynaria on bone remodeling during orthodontic tooth movement (OTM). SETTING: This study was conducted in School of Stomatology, Shandong University between 2009 and 2010 [Jinan, Shandong, China]. MATERIALS AND METHODS: Ninety-six eight-week-old female SPF Wistar rats 180-200 g were selected and randomly divided into four groups of 24: Dipsacaceae group, Salvia group, Drynaria group and control group. Animal models for orthodontic tooth movement were then established which consisted of a closed coil spring ligated to the upper first molar and incisors, exerting a force of 40 g during the experimental period. Rats in the TCM groups were given Dipsacaceae, Salvia and Drynaria decoction respectively by intragastric administration 6 g/kg/day and the control group were given normal saline 3 ml. The rats were sacrificed in batch on the 7th, 14th, 21st and 28th days after orthodontic treatment. Slices from periodontium of the upper first molar were observed under optical microscope. Neovascularization, new bone formation and osteoclast number were observed. RESULTS: The upper first molars were drawn mesial by the force. Telangiectasia and new bone formation in periodontal tissue were significantly in the TCM groups compared with the control group. Application of orthodontic forces in the experimental teeth showed a significant increase (P<0.05) of osteoclast number in the TCM group when compared with the control group. In addition, the number of osteoclast had no significant differences among the TCM groups (P>0.05). Osteoclast number in the TCM group and the control group were 10.12±0.058, 10.13±0.022, 10.09±0.047 and 9.55±0.045, respectively. CONCLUSIONS: These findings suggest that the TCM decoction are beneficial to the alveolar bone remodeling by promoting osteoclast differentiation during OTM.

Effects of selenium on the structure of the mandible in experimental diabetics.

In the treatment of diabetes-induced pathologies, beneficial results have been obtained with administration of antioxidants. Selenium is an antioxidant and essential trace element in living organisms. The aim of this study was to investigate the possible effects of selenium on the structural alterations of the mandible due to diabetes. In this study thirty-nine Wistar rats were used and a control, a selenium given control, a diabetic and a selenium given diabetes groups were formed. Experimental diabetes was induced by a single i.p. injection (50 mg/kg) of streptozotocin (STZ). The diabetic + selenium and the control + selenium groups were injected with a daily dose of 5 micro mol/kg/day sodium selenite (i.p.) for 4 weeks while the diabetic and the control groups were injected with distilled water. Mandibles of all the animals were excised and examined at the 5th week. High blood glucose level and low body weight in the diabetic group were not significantly affected by selenium administration. Furthermore, a negligible increase in blood glucose level was observed in the selenium given control group. Densitometric analysis revealed a significant reduction in bone density and presence of resorption in the diabetic and the selenium given control groups as compared to the selenium given diabetes and the control groups. In X-ray diffraction analysis, the reduction in peak intensity of the reflected light in both the diabetic and the selenium given control groups indicated a possible alteration in the crystallinity or a poor crystalline substance. Histological investigation showed that there was progressive resorption, trabecular and cortical irregularity and vascular proliferation in the diabetic and the selenium given control groups, whereas a more healthy appearance was detected in the selenium given diabetes group. The results of this study suggest the positive effects of selenium on diabetes-induced structural alterations in the mandible. However, the unexpected results in the selenium given control group necessitate further studies on the mechanism of selenium effects in organisms.

The triangle of safety: a modified posterior superior alveolar injection technique based on the anatomy of the PSA artery.

The posterior superior alveolar (PSA) injection technique is commonly used to anesthetize soft and hard tissues of the posterior maxilla. As with all injections, complications arise, including hematoma formation secondary to needle-induced vascular trauma. In an attempt to develop a hemorrhage-free PSA injection technique, 361 infratemporal dissections were completed on human cadaver specimens. Three distribution patterns were identified for the external branch of the PSA artery. Regardless of distribution pattern, an anatomical Triangle of Safety was found superior to the maxillary second molar that was free of neurovascular tissues in more than 99% of individuals. Injection into this area appears to meet anesthetic needs while reducing the risk of hematoma formation. The combination of this anatomical triangle with newer anesthetic agents and computerized delivery systems holds promise for continued improvement of the PSA injection technique.

[The long-term observation of alveolar bone blood flow during tooth movement with the aid of skeletal scintigraphy in an animal model]. / Langzeitbeobachtung der alveolären Knochendurchblutung während der Zahnbewegung mit Hilfe der Skelettszintigraphie im Tiermodell.

We observed in eleven dogs the blood flow in the alveolar bone during the tooth movement with the bone scintigraphy for one year. Additional we used for histological evaluation polychrome sequence marking and for improving of therapy electrostimulation. There is a correlation between tooth movement and blood flow. Four to six weeks after beginning tooth movement and blood circulation are reduced although the applied force was continuous all the time. This is an advice for stress interruption during treatment. Electrostimulation improves the conditions for tissue regeneration because the lifetime of osteoblasts is prolonged.

Bioelectric stimulation and residual ridge resorption.

The use of exogenous pulsed electromagnetic fields (PEMF) to stimulate the healing of nonunions and other long bone defects is common in medicine. This investigation used the dog model and image analysis of standardized radiographs to assess loss of residual ridge height following extractions. It demonstrates the effectiveness of intermittent PEMF to reduce the rate of residual ridge resorption. It further suggests there may be a causal relationship between residual ridge resorption and the alteration of endogenous bioelectric signals caused by the loss of teeth.