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Biomedical subjects

N S Seale

Publications and source records attributed to N S Seale.

At least 19 recordsLinked to original sources
PubMed2001

Purposeful assessment techniques (PAT) applied to an OSCE-based measurement of competencies in a pediatric dentistry curriculum.

Careful measurements of knowledge, attitude, and psychomotor and communication skills are necessary components of testing in a competency-based approach to education in dentistry. In an effort to address these requirements, Baylor College of Dentistry (BCD), Dallas, Texas, has applied Purposeful Assessment Techniques (PAT) to the Objective Structured Clinical Examination (OSCE) currently in use. PAT are those techniques that allow one to work toward development of linear measurement scales that are "person-free" and "item-free." Person-free measurement means that useful data are produced regardless of the group being measured and item-free measurement means that it does not matter which mix of items is completed over the course of an assessment. The Rasch probabilistic model and a guiding definition of Objective Measurement were used in an effort to implement PAT for the BCD OSCE. A Rasch analysis of a BCD-administered OSCE produced an item map that demonstrated the range of difficulty of items by student performance. This item map can be used to determine which items can be repeated on subsequent tests to allow for linear measurement of students' progression through the curriculum. The movement toward PAT described in this paper demonstrates how careful and evolving measurement in dental education can be of great benefit to faculty, staff, students, and the public.

Clinical Competence↗
PubMed1998

Fenestration gingival defect in erupting permanent mandibular incisors: a case report.

Bilateral fenestration of the labial gingival tissue of the permanent mandibular central incisors is described. The situation was followed over a 2-year period with no treatment other than prophylaxis and oral hygiene instruction. The final outcome was an apical positioning of the gingival margin, which was lower than that of the adjacent uninvolved teeth.

Child↗
PubMed1997

Funding sources for research for advanced education students in pediatric dentistry.

1. Of the hospital programs, 10 of 17 (41%) reported no funding requirement while only 5 of 33 (15%) school based programs reported no funding requirement. 2. Departmental funds were identified most often (N = 28) and ranked number one most often (N = 16) as the funding source for graduate student research. 3. The average level of research funding available for each student ranged from $100 to $3,500, with an average of $1,250. 4. One-half of the programs reported no change in their funding levels over the past five years. 5. Programs associated with dental schools reported more funding opportunities available to their students than programs associated with hospitals.

Certification↗
PubMed1994

Craniofacial morphology of spinal muscular atrophy.

Spinal muscular atrophy (SMA) is the second most common neuromuscular disease of childhood. It is the most common fatal recessive neuromuscular disease. This study is the first to evaluate the craniofacial growth of SMA patients. The results pertain to a sample of 25 SMA patients, between 5 and 32 y of age, who were case matched with unaffected normal controls. Group differences for 25 measures, derived from tracings of standardized cephalometric radiographs, were evaluated using multivariate analysis of variance. The SMA group showed excessive vertical development, particularly of the lower face. They demonstrated relatively larger anterior than posterior facial heights, due in part to a smaller cranial base angulation and a more anteriorly positioned mandibular ramus. Anteroposterior skeletal discrepancies of SMA patients, due to the combined effects of a protrusive maxilla and a retrusive mandible, were moderate. The interincisal angle of the SMA group was smaller than normal, due primarily to proclined maxillary incisors. Relative to palatal length, the SMA group had smaller anterior cranial base and mandibular corpus lengths. These results suggest abnormal craniofacial growth patterns of SMA patients. The etiology of the observed abnormalities seems to be complex and multifaceted, but attention to the treatment of malocclusion may be important for optimal nutrition and respiratory function.

Adolescent↗
PubMed1991

Comparison of antimicrobial and cytotoxic effects of glutaraldehyde and formocresol.

The in vitro antimicrobial and cytotoxic concentrations of glutaraldehyde and formocresol were determined. Minimal antimicrobial concentrations of these two agents against selected microbial flora reported in carious primary teeth were 3.125% for glutaraldehyde and 0.75% for formocresol. At a doubling of these concentrations, most organisms, except Candida albicans, Staphylococcus epidermidis, and Streptococcus mutans, were killed by both substances in 30 seconds. Cytotoxicity was evaluated on tissue cultures of pulp fibroblasts and HeLa cells at minimal cidal concentrations and at 10- and 100-fold dilutions. Exposure of pulp fibroblasts and HeLa cells to formocresol and indirect exposure to vapors caused the cells to become atrophic and to form a less dense tissue pattern. Cells directly exposed to glutaraldehyde retained their normal cell shape and tissue pattern, whereas cells indirectly exposed to vapors continued to proliferate. These data showed effective antimicrobial activity at concentrations of 3.125% glutaraldehyde and 0.75% formocresol and suggested that glutaraldehyde may exert a less cytotoxic effect on the immediate and surrounding tissues when used as a pulpotomy agent.

Bacteria↗
PubMed1991

Cytotoxicity of amalgams, alloys, and their elements and phases.

The purpose of this study was to compare the relative cytotoxicity of amalgams, alloys, and their constituent elements and phases, by means of a rapid and sensitive in vitro cell culture test. Pure copper and zinc showed intensive cytotoxicity, significantly greater than that of pure silver and mercury. Pure tin was non-cytotoxic. The gamma-one phase (Ag2Hg3) revealed moderate cytotoxicity, which was significantly decreased by the addition of 1.5% and 5% Sn. However, the addition of 1.5% Zn to gamma 1 containing 1.5% Sn dramatically increased the cytotoxicity of gamma 1 to the same level as that of pure zinc. Whenever zinc was present in amalgams, higher cytotoxicity was revealed. High-copper amalgams showed the same cytotoxicity as a zinc-free low-copper amalgam. The addition of selenium did not reduce the cytotoxicity of amalgam. The cytotoxicity of amalgams was reduced after 24 h. The results of this study suggest that the major contributor to the cytotoxicity of alloy for amalgam is probably copper, while that for amalgam is zinc.

Copper↗
PubMed1991

Spin-off applications of mouthguards.

The spin-off applications of mouthguards are many and varied. Their uses range from protective to therapeutic and span all areas of medicine and dentistry. The designs range from simple minor modifications of the soft athletic mouthguard to sophisticated adaptations containing gears or electric switches. Their creative applications have provided relief to the cancer patient, increased independence to the handicapped and limited mobility patient, protection to the dentition of the patient undergoing general anesthesia, relief for the TMJ syndrome sufferer, and decreased risk of damage to the teeth and palate of the intubated infant, to name only a few. The adaptations and applications of this simple device are inspired by the needs of the patient and limited only by the imagination of the provider.

Equipment Design↗
PubMed1989

[Evaluation of cytotoxicity of VLC Dycal in tissue culture for clinical use].

The purpose of this study was to evaluate the VLC Dycal (visible light cured composite-calcium hydroxide material) to see whether it is suitable or not as a direct or indirect pulp capping agent for clinical use by means of the cell culture test. Two light cured composite resins, P-30 and Silux, and also Dycal and Ca(OH)2 were used as a control for a comparative cytotoxicity test with VLC Dycal. All test materials were put into the glass tubes (4 mm diameter X 1 mm high), then illuminated for 10, 20, 30, 40, 50 and 60 seconds through a matrix strip with direct contact with a Prisma-light source (L.D. Caulk), just before testing. Fibroblasts, 5 ml of 1 X 10(5) cells per ml in Eagle's MEM medium with 10% FCS, penicillin (100 U/ml) and streptomycin (100 micrograms/ml) were evenly seeded on a cover glass in a tissue culture dish and incubated for 24 hours at 37 degrees C in a humidified atmosphere of a 5% CO2 in air. After 24 hours, the medium was replaced with 5 ml of agar overlay medium consisting of 10% FCS, Eagle's MEM medium and 1.5% agar. Glass tubes (n = 8) filled with the test materials were placed at the center of the agar, and incubated for 24 hours in 5% CO2 in air at 37 degrees C. After 24 hours of incubation, the cover glass was removed and the cells were fixed in 10% neutral formalin and then stained by H.E. to differentiate the areas of affected and unaffected cells beneath the test specimens. The affected area was quantitatively determined using an image analysis system.(ABSTRACT TRUNCATED AT 250 WORDS)

Bisphenol A-Glycidyl Methacrylate↗
PubMed1989

The prevalence of fluorosis-like lesions associated with topical and systemic fluoride usage in an area of optimal water fluoridation.

The frequency of using self-applied (over-the-counter) fluoride products and prescribed supplemental fluorides, and the prevalence of fluorosis-like enamel lesions in the permanent dentitions of children living in an optimally fluoridated urban community were investigated. Subjects were selected randomly, and consent forms and questionnaires concerning fluoride usage and residency status were provided to guardians prior to examination. After a supervised tooth brushing event, 300 consenting subjects were examined by the principal investigator using Dean's index to assess levels of fluorosis-like lesions. The principal investigator was standardized with another investigator prior to the examinations to obtain an interexaminer agreement level of 97%, and an intraexaminer agreement level of 96%. Portable dental equipment was used during all examinations. Chi-square analysis indicated no statistically significant difference between the frequency of tooth brushing with a fluoridated dentifrice at an early age and the prevalence of fluorosis-like enamel lesions. However, there was a significant difference (P less than 0.05) between the prevalence of fluorosis-like lesions, and the frequency of using prescribed fluoride supplements and gels, and over-the-counter rinses.

Adolescent↗
PubMed1988

Long-term evaluation of human teeth after Le Fort I osteotomy: a histologic and developmental study.

Transient pulpal vascular ischemia and direct injury to the apices of the teeth have been implicated as the causes of degenerative and atrophic pulpal changes in experimental animals after Le Fort I osteotomy despite the presence of collateral circulation. The long-term clinical effect of these pathologic changes in human teeth has not been studied. Seventeen maxillary third molar teeth from 10 patients whose postsurgical follow-up ranged from 6 months to 78 months (mean, 40 months) were extracted. The long-term biologic effects of Le Fort I osteotomy on the pulp and on the development of teeth were retrospectively evaluated with clinical and standard histologic techniques. Normal teeth from patients who were not operated on were used as controls. Histologic examination revealed an intact pulpal circulation and minimal pathologic changes in the pulpal tissue. Clinical and radiographic studies showed that the growing teeth developed normally after surgery. The Le Fort I downfracture procedure had little discernible long-term effect on the pulp and on the development of human third molar teeth.

Adolescent↗
PubMed1988

Cytotoxicity of amalgams.

The purpose of this study was to compare the relative cytotoxicity of amalgams and to determine whether their toxicity depends upon composition and aging time, by means of a rapid and sensitive in vitro cell culture test. Zinc-containing amalgams showed higher cytotoxicity than did any other amalgams. High-copper amalgams had the same cytotoxicity as did the low-copper amalgam. The addition of selenium did not reduce the cytotoxicity of amalgam. Moreover, excessive additions of selenium increased the cytotoxicity of amalgam compared with that of a similar selenium-free material. The cytotoxicity of amalgam was decreased with aging time, possibly due to the combined effects of surface oxidation and further amalgamation.

Cells, Cultured↗
PubMed1985

Systematic assessment of color removal following vital bleaching of intrinsically stained teeth.

Various treatment variables associated with a standard bleaching technique were systematically recorded in 53 individuals exhibiting intrinsic discoloration of permanent teeth. These variables (predictors) included: (1) etiology (fluoride or tetracycline); (2) age of the patient; (3) the presented color of the stain; (4) the intensity of that color; (5) a long versus short bleaching time technique; and (6) the number of bleaching sessions. These were assessed as to their relationship with the results of treatment (dependent variable). The findings of a multiple regression analysis revealed that the contributions of the individual predictors were significantly different between those stains caused by tetracycline ingestion (N = 27) and those stains due to fluoride ingestion (N = 20). The analysis also revealed that those variables contributing to a significant proportion of the variance in results of treatment when tetracycline was the cause were: (1) the color of the stain and (2) the number of bleaching sessions. When fluoride was apparently the causal agent: (1) the bleaching time technique; (2) age of the patient; (3) color of the stain; and (4) the number of bleaching sessions contributed to a significant proportion of the variance in the results of treatment.

Adolescent↗