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Biomedical subjects

Y Zilberman

Publications and source records attributed to Y Zilberman.

At least 55 records · Page 3Linked to original sources
PubMed1984

Surgical exposure, orthodontic movement, and final tooth position as factors in periodontal breakdown of treated palatally impacted canines.

Twenty-three patients who had completed orthodontic treatment for the resolution of unilateral palatal canine impactions were examined 2.3 years (mean) after all appliances were discarded. The patients were divided into two groups on the basis of whether the surgical exposure was "light" or "heavy." The whole group was also divided according to the type of orthodontic movement that was carried out--"light" for tipping, extrusive, and rotating movements and "heavy" for root movements. Final position of the teeth was classified as ideal or incomplete if rotations or spaces were present. The results showed marked deteriorative changes where the surgery had been more radical and where the tooth movement involved active alteration of root position. No change due to abnormal tooth position was seen. It is suggested that, in these cases, surgical procedures be limited in scope and that exposure of the cementoenamel junction be avoided.

Alveolar Process↗
PubMed1984

Periodontal status following the alignment of buccally ectopic maxillary canine teeth.

Twenty-nine patients who had completed orthodontic treatment to resolve buccal displacement of maxillary canine teeth were examined 2.9 years (mean) after all appliances had been discarded. Thirteen of these patients had unilateral displacement, and sixteen were bilaterally affected. In the unilateral cases only the width of attached gingiva was significantly less than in the controls. In the bilateral cases the same observation was made, but here the gingival index and pocket depth also showed statistically significant increases, although the expression of these values was found to have doubtful clinical significance. Posttreatment periodontal assessment is recommended for these cases.

Adolescent↗
PubMed1984

Osseous adaptation to continuous loading of rigid endosseous implants.

Titanium implants, with an acid-etched surface, were screwed into holes 3 mm in diameter, about 1 cm apart, carefully prepared with an internally irrigated, surgical bur in the femurs of 3- to 6-month-old rabbits. During the first 3 days after surgery, fluorescent bone labels revealed extensive bone formation, particularly at the endosteal margin of the surgical defect, indicating preservation of a high degree of osteogenic capacity. A lattice of coarse, woven bone began encapsulating the implant within 3 days. By the end of 6 weeks, mature, lamellar bone filled voids at or near the implant surface and a rigid bone/implant interface was routinely achieved. Nonspecific, subperiosteal bony hypertrophy was noted within 6 weeks after implants were placed in young, growing animals (3 months old), but not in adults (6 months old). After 6 to 12 weeks of healing, a 100-gm load was applied for 4 to 8 weeks by stretching a stainless steel spring between the implants. All but one of twenty loaded implants remained rigid. Immediate loading of four pairs of implants resulted in spontaneous spiral-type ("torsional") fractures of the femur within 1 week. These results indicate that (1) relatively simple and inexpensive titanium implants develop a rigid osseous interface, (2) 6 weeks is an adequate healing period, prior to loading, to attain rigid stability and avoid spontaneous fracture, (3) continuously loaded implants remain stable within the bone, (4) bone formation is observed on periosteal surfaces subjected to concave flexure (compression), (5) cancellous-type bone orients perpendicularly between loaded implants, apparently corresponding to lines of stress, (6) new secondary osteons are propagated at or near the surface of loaded implants, (7) the remodeling (turnover) cycle for rabbit compact bone is about 6 weeks, and (8) endosseous implants have potential as a source of firm osseous anchorage for orthodontics and dentofacial orthopedics.

Animals↗
PubMed1983

Periodontal status following the alignment of palatally impacted canine teeth.

Twenty-three patients who had completed treatment to resolve the unilateral palatal impaction of a maxillary canine by orthodontic means were examined 2.3 years (mean) after all appliances had been discarded. Scores were noted for the plaque index, gingival index, attached gingiva, pocket depth, and bone support on each of the affected teeth and also on the contralateral canine which had been unaffected and thus acted as a control. In addition, the teeth immediately adjacent to both canines were similarly scored. The results indicated no significant difference in the plaque index and the amount of attached gingiva, while the gingival index, pocket depth, and particularly the bone support all showed statistically valid differences. It is suggested that in these cases a postorthodontic assessment of the state of the supporting tissues be performed and periodontal treatment instituted in those requiring it.

Alveolar Process↗
PubMed1983

Prevalence and severity of malocclusion in Israeli Arab urban children 13 to 15 years of age.

Israeli Arab children between the ages of 13 and 15 years, living in the town of Nazareth, were examined in order to determine the prevalence and severity of malocclusion in the permanent dentition. The survey encompassed 803 children, of whom 2.5 percent were under orthodontic treatment at the time of the study and 0.3 percent showed ideal occlusion. The remainder showed various measures of deviation from normal, distributed as follows: 85 percent had Angle Class I malocclusion, 8.5 percent had Angle Class II, Division 1 malocclusion, 1.7 percent had Angle Class II, Division 2 malocclusion, and 1.3 percent belonged to the Angle Class III category. The severity of malocclusion was appraised qualitatively by subjective evaluation, while for quantitative determination the Handicapping Malocclusion Assessment Record (HMAR) was used. There was a positive correlation between the two modes of assessment as expressed in the 12.4 percent of the children who were classified "treatment highly desirable or mandatory" and who scored 30 or more points on the HMAR chart. Further examination of the deviations underlying the scoring revealed that the 52.1 percent of the children with scores of 15 points or more would benefit greatly from orthodontic treatment. Selected items of the TPI and OI charts were incorporated into the HMAR to evaluate the latter's sensitivity. Supplementing the HMAR with some deviations from normal, such as cusp-to-cusp relationships, amplifies the sensitivity of this record.

Adolescent↗
PubMed1982

The effect of verapamil, lanthanum and local anesthetics of serotonin release from rabbit platelets.

The effect of calcium blockers (verapamil, local anesthetics and lanthanum chloride) on serotonin release from rabbit platelets was studied. The following results were obtained: (1) Verapamil and tetracaine (but not lanthanum) caused a time- and dose-dependent release of serotonin. The curves describing the time-course and those describing the concentration dependence of the release were sigmoid, suggesting cooperativity. (2) Thrombin-induced release from the platelets was dependent upon extracellular sodium ions, while no dependence was observed for the drug-induced release. (3) The release by verapamil was partially inhibited by prostaglandin E1 and theophylline which are known to raise intracellular cAMP levels, but was unaffected by the prostaglandin-synthesis inhibitor, indomethacin. (4) Verapamil, tetracaine and lanthanum inhibited thrombin-induced release of serotonin. The curve of dose dependence of the inhibition by verapamil and tetracaine was not sigmoid. The inhibition by verapamil and tetracaine was reversed by extracellular calcium ions, but no effect of this ion on the drug-induced release reaction was observed. It is concluded that the serotonin release induced by some calcium blockers and the inhibition of the thrombin-induced release by the same drugs are two separate phenomena. It is suggested that verapamil and tetracaine-induced release are mediated by exocytotic processes brought about by the interference of the drugs with calcium distribution between the cytosol and storage compartments within the platelet.

Alprostadil↗
PubMed1982

Gingival response to removable orthodontic appliances.

The gingival state of twenty-four young patients (mean age 9.4 years) wearing simple removable orthodontic appliances was assessed and followed at monthly intervals for 4 months. In nine of the patients intentional relief of the appliance was made in the upper right area. The plaque index levels were similar in both "relief" and "no-relief" groups and reached a similar score at 4 months. The gingival index was significantly higher in the "relief" group, and all five cases that showed gingival hyperplasia of the experimental area belonged to this group.

Adolescent↗
PubMed1981

Attenuation of the lithium-induced diabetes-insipidus-like syndrome by amiloride in rats.

The effect of amiloride on lithium-induced polydipsia and polyuria and on the lithium concentration in the plasma, brain, kidney, thyroid and red blood cells was investigated in rats, chronically treated with LiCl. Amiloride reduced the drinking and urine volume of rats in an acute (6 or 12 h) and a subacute (3 days) experiment. 6 h after the administration of amiloride, a reduction was observed in the lithium content of the renal medulla but not in the other organs studied. At 12 h, all the tissues showed a slight increase in lithium levels. After 3 days of combined treatment, a marked elevation in plasma and tissue lithium levels accompanied a reduction in water intake. In all the experiments, the attenuation of the lithium-induced diabetes-insipidus-like syndrome by amiloride was accompanied by a reduction of the ratio between the lithium concentration in the renal medulla and its levels in the blood and an elevation in the plasma potassium level. It is concluded that acute amiloride administration to lithium-treated patients suffering from polydipsia and polyuria might relieve these patients but prolonged amiloride supplementation would result in elevated lithium levels and might be hazardous.

Amiloride↗
PubMed1980

Clefts in quintuplets--a case report.

A report of clefting in three siblings of quintuplets, following treatment with Pergonal, is presented. It is suggested that the varying degrees of the abnormality may be related to cramped intra-uterine conditons or differing pressures at a critical developmental stage. To our knowledge, no previous reports of congential abnormalities associated with Pergonal therapy exist, and we feel that the causal relationship should be explored using a suitable animal model.

Alveolar Process↗
PubMed1979

Structural and kinetic studies on the solubilization of lecithin by sodium deoxycholate.

Mixed dispersions of egg phosphatidylcholine (PC) and the bile salt sodium deoxycholate (DOC) were prepared by various methods, and their turbidities and proton magnetic resonance spectra were studied as a function of time. The spectra of dispersions prepared by dissolving both components in a common organic solvent and replacing the organic solvent by water did not change with time, indicating that the mixed aggregates formed represent "a state of equilibrium". In the 1H NMR spectra of these mixed aggregates, only signals from small mixed micellar structures were narrow enough to be observed. The dependence of the NMR line widths on the molar ratio of DOC to PC (R) is interpreted in terms of a model for the PC--DOC mixed micelles, according to which PC is arranged as a curved bilayer, the curvature of which increases with increasing R. Upon mixing PC with aqueous solutions of DOC, we found that the mixed aggregates formed are slowly reorganized and ultimately reach the same state of equilibrium. This reorganization was found to be a pseudo-first-order process, the rate constant of which depends linearly upon the detergent concentration. This process involves saturation of the outer bilayers of the multilamellar PC by detergent, followed by transformation of these bilayers into mixed micelles. It is concluded that the solubilization occurs through consecutive "peeling off" of lecithin bilayers.

Deoxycholic Acid↗
PubMed1979

The use of phospholipid liposomes for lithium administration. Polydipsic effect and tissue distribution of lithium.

Administration of lithium entrapped in phospholipid liposomes increased the lithium-induced polydipsia, but did not accelerate the onset of this effect. It also resulted in a larger accumulation of lithium in the liver, kidney and spleen, but not in the brain. The time course of polydipsia suggests that it depends on the intracellular lithium concentration. However, the rate of development of this effect depends on some additional factor.

Animals↗
PubMed1978

The palatally impacted canine: a new approach to treatment.

A method for the application of traction to misplaced maxillary canines in the palate is described. The treatment approach is from the palatal side, with initial traction applied in a lingually downward direction to prevent interference with the neighboring teeth. Emphasis is placed on the suitability of the method as an adjunct to almost any of the established techniques. In this way improving their efficiency in treating the over-all orthodontic problem.

Child↗