The regeneration of bone is a remarkable, complex physiological process, and BMPs are a formidable clinical tool to promote its regeneration. By defining roles played by BMPs in developmental biology and bone regeneration, significant progress has been made to identify cell-signaling molecules and their regulators. For example, the regulators of BMPs that include noggin, chordin, cerberus, dan, and gremlin may be harnessed as therapies to offset calcification encountered after total hip arthroplasties. Furthermore, exploiting BMPs and Smads may generate new therapeutic options for bone repair. Another compelling clinical consideration is the trans-acting factor osteoblast-specific factor-2, which can promote osteoblast differentiation. Moreover, the affiliation of osteoblast-specific factor-2 with heritable disorders merits exploration. A recognized daunting challenge includes a carrier/delivery system for the powerful morphogenetic therapeutic tools, as well as osteoprogenitor cells and intracellular transduction and transcriptional factors. In addition, the long-term effects of administering superphysiological doses of rhBMPs to patients must be assessed systematically. A new generation carrier/delivery system may be the answer to offset dosing liabilities as well as to provide residence for exogenous, BMP-receptive osteoprogenitor cells (111,112). The areas highlighted in this review offer fertile territory for thought and research to develop rational clinical treatments to promote bone regeneration and to understand some of the biological roles of BMPs.
The aim of this study is to classify the nasal bone fractures based on computed tomography (CT) analysis and patterns of the nasal bone fractures, and review 503 cases treated between 1998-2004 at the Department of Plastic Surgery, Inha University Hospital, Incheon, South Korea. The age, sex, etiology, associated injuries, pattern of fractures and treatments were reviewed and a radiographic study was analyzed. Plain simple radiographs of lateral and Waters view of the nasal bones combined with computed tomography scans were done. Nasal bone fractures were classified into six types: Type I) Simple without displacement; Type II) Simple with displacement/without telescoping; IIA; Unilateral; IIAs) Unilateral with septal fracture; IIB) Bilateral; IIBs) Bilateral with septal fracture; Type III) Comminuted with telescoping or depression. Diagnosis of nasal bone fractures were made positively by plain x-ray films in 82% of cases, negative finding was 9.5% and 8.5% of cases were suspicious of the fractures. Reliability of the plain film radiographs of the nasal bone fracture was 82% in this study. In the most of the fractured nasal bones (93%) the closed reduction was done, open reduction in 4% and no surgical intervention in 3%. Nasal reduction was carried out in average 6.5 days post the injury. The patterns of the nasal bones fractures classified by CT findings were type IIA (182 cases, 36%), IIBs (105 cases, 21%), IIB (90 cases, 18%), IIAs (66 cases, 13%), I (39 cases, 8%) and III (21 cases, 4.3%). We think the CT is necessary for diagnosing nasal bone fracture because the reliability of the plain film was only 82%.
Microgenia or "small chin" is corrected by various techniques, such as insertion of an alloplastic implant, cartilage or bone grafting, or horizontal advancement osteotomy. Horizontal recession osteotomy is used in macrogenia. Particularly in a microgenic mandible, the mental foramen is unexpectedly nearer to the inferior border of the body. During sliding horizontal osteotomy of the mentum, the inferior alveolar nerve (IAN) and mental nerve are vulnerable to an injury. Thirty fresh hemimandibles were used for a study of the IAN. The IAN course was traced by serial sections at intervals of 5 mm. In 50 dry specimens the direction of the mandibular canal was evaluated by the photographs with a stick put into the mental foramen. The IAN in mandibular canal runs above the lower one-third of the mandibular body. The terminal mandibular canal locates at an average of 4.5 mm under the mental foramen, advances 5.0 mm anteriorly, loops, and ends at the foramen. The direction of the mandibular canal at the mental foramen was 39.4 degrees lateral, 67.2 degrees superior, and 80.2 degrees posterior. It is advisable for surgeons to keep the level of sliding osteotomy of the mentum at least 4.5 mm below the mental foramen to spare the IAN.
A limited number of experimental animal studies and in vitro data confirm that nicotine impairs bone healing, diminishes osteoblast function, causes autogenous bone graft morbidity, and decreases graft biomechanical properties. Therefore, our long-term goal is to develop an effective therapy to reverse the adverse impact of nicotine from tobacco products. However, before accomplishing this goal, we had to develop an animal model. Our hypotheses were nicotine administration preceding and following autogenous bone grafting adversely affected autograft incorporation and depressed donor site healing in a characterized animal wound model. Hypothesis testing was accomplished in bilateral, 4-mm diameter parietal bone defects prepared in 60 Long-Evans rats (male, 35-day-old). A 4-mm diameter disk of donor bone was removed from the left parietal bone and placed in the contralateral defect. The donor site served as a spontaneously healing bone wound. The rats were partitioned equally among three doses of nicotine administered orally in the drinking water (12.5, 25, and 50 mg/L). For each dose, the duration and sequence of nicotine treatment followed four courses, including no nicotine and designated combinations of nicotine administration and abatement prior to and following osseous surgery. Experimental sites were recovered on 14 and 28 days postsurgery, responses quantitated, and data analyzed by analysis of variance and post hoc statistics (p < or = 0.05). We developed a convenient and effective osseous model, and the results validated our hypothesis that nicotine negatively impacts on bone healing.
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