Search PubMed⌕ Search

Biomedical subjects

S Steigman

Publications and source records attributed to S Steigman.

At least 37 records · Page 2Linked to original sources
PubMed1985

Spaced dentition. An epidemiologic study.

This epidemiologic study deals with the incidence of spaced dentition in 1279 students between the ages of 12 and 18 years. The sample includes only those with a full complement of permanent teeth (third molars were not considered) and with no apparent etiological conditions that might lead to disruption of dental arch continuity. The sample was evenly divided by age and sex. Frequency of spaced dentition was high, occurring in 51.8% of males and in 45.5% of females. Prevalence was less in higher age groups, and the sexual dimorphism that was significant in the 14 YR-16 YR group was not found in the 16 YR-18 YR group. The mean number of spaces per subject was 6 +/- 4.3 for males and 5 +/- 3.7 for females, again displaying diminishing incidence with age and a concomitant absence of the sexual dimorphism in the highest age group. Spaces were found in both arches in 49.5% of the spaced dentitions, and in only the maxillary arch in 34.3%. Incidence of spacing in the mandibular arch alone was only 16.2%. In most subjects the spaces were distributed equally between the two quadrants of each arch. The most common sites and largest space widths in either dental arch were found between cuspids and the first bicuspids and between cuspids and lateral incisors.

Adolescent↗
PubMed1985

Characteristics and stability of spaced dentition.

A serial study of changes in spacing between teeth during the period of facial maturation, finding tendencies toward closure of buccal spaces and opening of anterior spaces. Spacing in females is equally distributed between upper and lower arches; in males it is more prevalent in the upper arch.

Adolescent↗
PubMed1984

Histomorphometric evaluation of the dimensional changes in rat-incisor tissues following histological processing and embedding in paraffin wax and glycol methacrylate.

A three-dimensional reconstruction of undemineralized and paraffin wax- or or glycol methacrylate-embedded demineralized rat incisors was made using a computerized histomorphometry. Compared to the undemineralized ground sections, the two demineralizing and embedding procedures grossly distorted the tooth sections. In general, embedding in wax caused shrinkage and in methacrylate caused swelling. Direction and magnitude of the deformation varied in the different tissues of the tooth and its surrounding structures. The distortion was influenced by the ratio between the soft and hard tissues at different cross-sectional levels of the tooth.

Animals↗
PubMed1983

Long-term effect of intrusive loads of varying magnitude upon the eruptive potential of rat incisors.

The present investigation deals with the functional recovery of the periodontium following application of intrusive loads of varying magnitudes to continuously growing rat incisors. The daily rate of eruption of these teeth served as an indicator of the functional capacity of their periodontal ligament. The left mandibular incisor was shortened to prevent occlusion in thirty experimental and ten control rats. The experimental animals were divided into three groups and constant, calibrated axial loads of 8 Gm./cm.2 (light), 15 Gm./cm.2 (medium), and 26 Gm./cm.2 (heavy) were applied to their incisors by means of closed-coil springs for a period of 2 weeks. The daily eruption rate of all teeth was measured for 80 days following removal of the springs. In all experimental animals, severe and long-lasting impairment of the eruptive potential occurred. The least impairment was seen in the group with the light loads, their eruption rate being fully restored 64 days after removal of the loads, by which time 165 percent of all dental and periodontal tissues was renewed. In the medium-load group, renewal of the tissues reached 140 percent, while a gross impediment in normal eruption rate persisted throughout the entire experimental period. The teeth subjected to heavy loads received a diminished impact of the axially directed loads due to the strong horizontal component of force; consequently, they behaved like the incisors of the light-load group. The light loads proved to cause the least impairment and were the most beneficial to functional recovery.

Animals↗
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

Submerging primary molars in Israeli rural children.

Dental study casts of 1530 Israeli rural children aged 3-13 years, evenly represented by the sexes, were examined for submersion of their primary molars, 24.8% of the children had one or more of these teeth affected. Out of 8250 teeth at risk, 8.81% were submerged to various degrees. Over 50% of them were primary mandibular first molars, close to 26% were primary mandibular second molars. The number of affected teeth rose with age in both sexes. Sex differences were significant only at 5-7 years, when girls were more frequently affected. Children with one or two affected teeth predominated. The submerged teeth were predominantly located in one or in both quadrants of the same arch. The degree of submersion became more severe with age.

Adolescent↗
PubMed1982

Ethnic variability in the prevalence of submerged primary molars.

Dental submergence, linked primarily with tooth ankylosis, has been reported to have a possible genetic predisposition. The submergence of primary molars was examined in a sample of 1530 children, 2.5-13.5 yr old, appertaining to seven ethnic groups living in Israel. It was found that the frequency of submergence varied among the ethnic groups, and that, on the whole, it was considerably higher than that in North American children.

Adolescent↗
PubMed1981

Experimental intrusion of rat incisors with continuous loads of varying magnitude.

The present investigation deals with the relationship between continuous intrusive loads and the rate of intrusion of rat incisors. A method for the application of constant, defined loads by means of a closed coil spring is described. In seventeen rats the left mandibular incisor was shortened to prevent occlusion. The animals were exposed to direct light, medium, and heavy intrusive loads for a period of 12 days. Light loads (1.5 to 8.0 Gm./cm.2) did not cause active intrusion of the teeth. Medium loads (12.0 to 18.5 Gm./cm.2) initially elicited marked intrusion, followed by a short rest period after which the intrusive movement progressed steadily at a daily rate of about 25 micrometers. Heavy loads (30.5 to 32.0 Gm./cm.2) brought about active intrusion, which commenced only after 8 days of force application. The medium loads, having a magnitude in the range of rat systolic blood pressure, proved to be optimal for the intrusive movement.

Animals↗
PubMed1980

Electric currents, bone remodeling, and orthodontic tooth movement. I. The effect of electric currents on periodontal cyclic nucleotides.

Osteogenesis has been found to occur in response to the application of electric currents to bone. The objective of this experiment was to study the effects of D.C. electric currents on periodontal tissues in cats. Cyclic nucleotides, compounds known to be involved in cellular activation, were studied by immunohistochemistry in the involved tissues. Three groups of three young adult cats each were treated for 1, 3, and 7 days, respectively, by a device delivering 15 microamperes of direct current to bone osteoblasts and PDL cells stained intensely for cAMP and cGMP were observed adjacent to the cathode and anode, and bone apposition was found near the cathode. These results suggest that electric stimulation enhances cellular enzymatic phosphorylation activities in periodontal tissues and may be a potent tool in accelerating alveolar bone turnover.

Alveolar Process↗
PubMed1980

Electric currents, bone remodeling, and orthodontic tooth movement. II. Increase in rate of tooth movement and periodontal cyclic nucleotide levels by combined force and electric current.

Piezoelectric currents in mechanically stressed bone were implicated in the activation of bone cells. The objectives of this experiment were to determine the usefulness of exogenous electric currents in accelerating orthodontic tooth movement and to study the effect of electric-orthodontic treatment on periodontal cyclic nucleotides. Maxillary canines were tipped in five cats by 80 g force. Two groups of five cats each were treated by an electric-orthodontic procedure to one maxillary canine for 7 and 14 days, respectively. Teeth treated by force and electricity moved significantly faster than those treated by force alone. Enhanced bone resorption was observed near the anode (PDL compression site), while bone formation was pronounced near the cathode (PDL tension site). Staining for cyclic nucleotides was increased when electric stimulation was added to the mechanical force. These results suggest that orthodontic tooth movement may be accelerated by the use of locally applied electric currents.

Alveolar Process↗