[An evaluation of the reparative regeneration of maxillary defects based on neutron activation analysis data (experimental research)]. / Otsenka reparativnoi regeneratsii defektov verkhnei cheliusti po dannym neitronno-aktivatsionnogo analiza (éksperimental'noe issledovanie).

The major mineral components and electrolytes (K, P, Mg, Na, Cl, Mn, Fe, Co, Zn, Br, Sr) of the maxillary lamellar bone tissue and of the reparative regenerate were examined over the course of healing of maxillary nasofrontal artificial defects of various sizes (5 X 20, 7 X 20, 10 X 20 mm) perforating the nasal cavity. Check-ups carried out in 3, 4, and 8 mos after surgery have shown no osteal joining of the maxillary defect. The level of ossification by the 8th month of the follow-up, as evidenced by the content of the major osteotropic elements, just a little surpasses 50-70% of the normal value.

Leukotrienes in orthodontic tooth movement.

Prostaglandins (PGs) and leukotrienes (LTs) are products of arachidonic acid conversion. PGs have an established role in mediating orthodontic tooth movement. The role of LTs in modulating or mediating orthodontic tooth movement was investigated in this study. One hundred thirty-two Sprague-Dawley rats were used; the animals weighed 300 to 400 gm with equal numbers of male and female rats. They were divided into five main groups of 24 animals each and a sham group of 12 animals. An orthodontic appliance was placed and activated on all the animals except the sham group; in this group the appliances were not active. Each main group was given one of the following treatments daily: distilled water, 5% gum arabic solution, PG synthesis inhibitor indomethacin, LT synthesis inhibitor AA861, and a combination of both drugs. Each group was divided into six subgroups of four animals; the animals were killed at either 1, 3, 5, 7, 10, or 14 days, and tooth movement measured. The three sham subgroups received distilled water and were killed at 1, 7, or 10 days. The first maxillary molar (the moved tooth) and surrounding tissues were removed from all animals in the sham group and the subgroups killed at 1, 7, and 10 days in the gum arabic solution group and the LT synthesis inhibitor group. Prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) were extracted, measured with radioimmunoassay (RIA), and standardized per milligram of protein in the sample. A significant inhibition of tooth movement occurred beginning on day 7 in the indomethacin, AA861, and combination groups; there was no significant difference among these groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Miokamycin penetration into oral cavity tissues and crevicular fluid.

Diffusion of miokamycin into gum, maxillary-mandibular bone and crevicular fluid was studied in human beings. The antibiotic concentrations were determined in specimens at different times after oral administration of 600 mg in a single dose of miokamycin. Peak serum levels (2.32 +/- 0.67 mcg/ml) were found at the first hour after dosage. In healthy gum tissue the highest antibiotic levels (1.44 +/- 0.34 mcg/gr) were observed at the second hour, while in the inflamed gum miokamycin penetrates more rapidly, being, as in serum at the highest levels detectable during the first hour. In the bone of the maxilla or mandible the highest levels of miokamycin (0.88 +/- 0.13 mcg/gr) were detected at the second hour after treatment. In the crevicular fluid miokamycin showed a similar profile as that in serum, since the peak levels were reached at the first hour (2.4 +/- 0.88 mcg/ml, but the decrease of the antibiotic occurred more slowly than in serum. Miokamycin rapidly penetrates into tissues and fluids of oral cavity. A single oral dose of 600 mg guarantees antibacterial levels against susceptible bacteria over six hours.

Photodensitometric evaluation of osseous repair following Le Fort I osteotomy.

This study evaluated photodensitometry as a noninvasive method for quantitating bone mineral content (BMC) and osseous repair after Le Fort I osteotomy. Le Fort I osteotomies were performed on 6 Macaca fasicularis monkeys; maxillas were either advanced (Group I, n = 3) or impacted and advanced (Group II, n = 3). Postoperative, standardized lateral cephalometric films were taken at weekly intervals up to 25 weeks and osteotomy site repair was studied using photodensitometry. Segment stability was also evaluated and correlated with measured densities. In both experimental groups, clinical stability occurred at about the same time (45.7 and 48.7 days postoperatively) despite large differences in the size of the initial surgical defects. The net rate (slope) of osteotomy site remineralization was significantly different (Group II greater than Group I), but the relative difference in film absorbance between the osteotomy site and adjacent bone at the time of clinical stability was the same. This difference can be extrapolated from early postoperative films and may constitute a useful parameter for predicting when clinical stability will be achieved.

Dystrophic calcification in calcifying epithelial odontogenic tumor: an X-ray diffraction and electron spin resonance study.

X-ray diffraction and electron spin resonance (ESR) analyses were conducted on calcifying epithelial odontogenic tumor (CEOT) associated with abundant calcification in order to compare its mineral structure with that of surrounding cortical bone. The material under investigation was removed from the canine-premolar region of the left maxilla of a 39-year-old woman. The principal findings were that the mineral phase of CEOT consists of apatite crystals and that the crystallinity of the crystals is higher than that of bone apatite. ESR spectra of CEOT are similar to those of bone sample. Quantitative ESR analysis indicates that CEOT shows a higher crystallinity coefficient -- defined by Ostrowski et al. (1972, 1974) as the ratio of spin concentration to the ash content of the sample -- than bone. Based on the data, it can be concluded that the calcification in CEOT has a higher crystalline structure than the cortical bone.