The nasal septum in relation to the development of the nasomaxillary complex: a study in identical twins

The influence of the nasal septum and respiration, evaluated by the total nasal resistance (TR) on the development of the nasomaxillary complex, was studied in 42 identical twins. An understanding of this influence is important for a determination of whether surgery involving the nose should be performed in children. Comparison within and between twins with different septal deformities indicated that the cartilaginous nasal septum influences the development of the nose and the anteroposterior dimensions of the maxilla. Anterior septal deformities resulted in underdeveloped cartilaginous noses and a shorter anteroposterior dimension for the maxilla. No relation was found with regard to posterior septal deformities, which may be considered as part of the development of the midface. Vertical dimensions of the face were related to TR. Increased values of TR were significantly related to a shorter maxillary height. This may not express a causal relationship but rather genetically determined shorter facial dimensions.     

Structural and histomorphometric studies of iliac crest trabecular and cortical bone in autosomal dominant osteopetrosis: a study of two radiological types

Cylindrical iliac crest biopsies were obtained from 16 patients with autosomal dominant osteopetrosis after intravital double labeling with tetracycline, and compared with normal age- and sex-matched controls. Ten patients had the radiological type I (5 women, 5 men, aged 17-62 years, mean 42) characterized by diffuse, symmetrical osteosclerosis and enlarged thickness of the cranial vault. Six patients had type II (2 women, 4 men, aged 22-44 years, mean 36), where "Rugger Jersey Spine" and endobone are characteristic findings. Structural studies of cortical and trabecular bone were performed, and trabecular bone resorption and formation rates were studied using dynamic histomorphometry. The total biopsy length (C. Wi) were increased in type I (p less than 0.05), and unchanged in type II. Both types showed increased cortical width (Ct. Wi) (p less than 0.01 and p less than 0.05, respectively), and decreased fractional width of cancellous bone (Cn.Wi/C.Wi) (p less than 0.01 and p less than 0.05). The fractional trabecular bone volume (BV/TV) and trabecular thickness (Tb. Th) were both significantly increased in type I (p less than 0.05), while resorptive and formative indices of trabecular bone remodeling were normal. No difference was found in trabecular bone balance, which was slightly positive in both patients and controls. In type II osteopetrosis the eroded surfaces (OS/BS) were significantly increased (p less than 0.01), as was the total resorptive period RP) (p less than 0.05). The resorption depth (R.D.) was normal, while the resorption rate (MRR) was insignificantly decreased. Many big multinucleated osteoclasts were seen in this type suggesting defective resorptive function.(ABSTRACT TRUNCATED AT 250 WORDS)     

Marrow space star volume in the iliac crest decreases in osteoporotic patients after continuous treatment with fluoride, calcium, and vitamin D2 for five years

Iliac crest biopsies in osteoporotic patients were obtained before and after five years of continuous treatment with sodium fluoride (40-60 mg/d), vitamin D2 (18,000 IE/d), and calcium phosphate (45 mmol/d). Star volume of marrow space and trabeculae, mean trabecular thickness, and fractional amount of trabecular bone were estimated on so-called vertical sections before and after treatment. Results showed a significant decrease in marrow space star volume after five years of treatment (35 mm3 versus 19 mm3) (2p less than 0.02). No significant changes were observed in trabecular star volume (0.149 mm3 versus 0.104 mm3) (2p greater than 0.50) or mean trabecular thickness (85 microns versus 79 microns, 2p greater than 0.30). A slight but insignificant increase in the fractional amount of trabecular bone was found (9.7% versus 10.4%, 2p greater than 0.50). A rather close inverse correlation was obtained, however, between individual changes in trabecular bone volume fraction and marrow space star volume (r = -0.72, 2p = 0.011). The findings suggest that the large marrow "cavities" had been split into two or more "cavities" by some newly generated trabecular structures leading to increased trabecular connectivity. The strength of trabecular bone may be increased due to this beneficial effect of fluoride on trabecular bone structure.     

Bioactive nano‐fibrous scaffold for vascularized craniofacial bone regeneration

There has been a growing demand for bone grafts for correction of bone defects in complicated fractures or tumours in the craniofacial region. Soft flexible membrane like material that could be inserted into defect by less invasive approaches; promote osteoconductivity and act as a barrier to soft tissue in growth while promoting bone formation is an attractive option for this region. Electrospinning has recently emerged as one of the most promising techniques for fabrication of extracellular matrix such as nano‐fibrous scaffolds that can serve as a template for bone formation. To overcome the limitation of cell penetration of electrospun scaffolds and improve on its osteoconductive nature, in this study, we fabricated a novel electrospun composite scaffold of polyvinyl alcohol (PVA)‐poly (ε) caprolactone (PCL)‐Hydroxyapatite based bioceramic (HAB), namely, PVA‐PCL‐HAB. The scaffold prepared by dual electrospinning of PVA and PCL with HAB overcomes reduced cell attachment associated with hydrophobic PCL by combination with a hydrophilic PVA and the HAB can contribute to enhance osteoconductivity. We characterized the physicochemical and biocompatibility properties of the new scaffold material. Our results indicate PVA‐PCL‐HAB scaffolds support attachment and growth of stromal stem cells; [human bone marrow skeletal (mesenchymal) stem cells and dental pulp stem cells]. In addition, the scaffold supported in vitro osteogenic differentiation and in vivo vascularized bone formation. Thus, PVA‐PCL‐HAB scaffold is a suitable potential material for therapeutic bone regeneration in dentistry and orthopaedics.     

Osteopenia with normal vitamin D metabolites after small-bowel resection for Crohn's disease

Thirty-six unselected patients were investigated 3-24 years (mean, 7.8 years) after small-bowel resection for Crohn's disease (mean small intestinal resection, 105 cm). Iliac crest bone biopsies after in vivo tetracycline double-labelling showed a markedly reduced trabecular bone mass (controls, 0.25 +/- 0.06; patients, 0.15 +/- 0.05; p less than 0.01). The average bone remodeling and osteoid mineralization was normal, and only two patients demonstrated signs of frank but slight osteomalacia. The mean serum levels of the three vitamin D metabolites 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, and 1,25-dihydroxyvitamin D were normal. The observed reduction in trabecular bone mass may theoretically be followed by an increased risk of spontaneous fractures.     

Experimental infusion thrombophlebitis

On the basis of clinical experience it has been claimed that glucose results in a higher incidence of infusion thrombophlebitis than fructose, and that glucose solutions in concentrations higher than 5% are extremely irritant to the venous endothelium. The validity of these two assertions has been investigated by an experimental method based on a quantitative histological study of rabbit-ear veins into which infusions were given under standardized conditions. In two series of experiments, it was shown (1) that fructose solutions caused significantly more inflammatory changes in the veins than did glucose solutions, and (2) that glucose in 10% solutions caused significantly more injury to the veins than 5% solutions, although the difference in the average inflammatory changes was only slight.     

Two-vector mechanics

The conventional orthodontic appliance is not without its limitations for certain types of tooth movements; in particular, if the appliance cannot access the area to elicit the type of force vector for a particular displacement. Examples of such movements are: space closure by translation, uprighting and intrusion of posterior teeth, intrusion with retraction and lingual root torque of anterior teeth. In this paper we describe a mathematical method to design an appliance system that overcomes these difficulties. This system includes two statically determined elements and allows for highly controlled force vector application point and direction. A clinical case of midline discrepancy is shown to demonstrate the clinical use and utility of this method.