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Biomedical subjects

A Glaros

Publications and source records attributed to A Glaros.

8 recordsLinked to original sources
PubMed2002

Clinical bond failure of pre-coated and operator-coated orthodontic brackets.

OBJECTIVES: To test the hypothesis that there is no significant difference in clinical bracket failure between the 3M APC Mini Twin bracket system and the Transbond XT adhesive during orthodontic treatment. DESIGN: A randomized, split mouth, prospective clinical trial. SETTING AND SAMPLE POPULATION: The Department of Orthodontics and Dentofacial Orthopedics at University of Missouri, Kansas City. Twenty-nine subjects who were treatment planned to receive comprehensive orthodontics using 0.018 slot appliances. EXPERIMENTAL VARIABLE: The adhesive pre-coated brackets (APC) system was randomly assigned to one side of the mouth and the Transbond XT was assigned to the opposite side. OUTCOME MEASURE: The absence of any of the brackets at the time of a regular or emergency orthodontic appointment. RESULTS: There was no significant difference (P > 0.05) in bracket failure between the 3M APC Mini Twin bracket system and the Transbond XT adhesive at any time period (90, 180, or 365 days). The failure rate of brackets on premolars was higher than on incisors or canines. CONCLUSION: APC Mini Twin bracket system and Transbond XT adhesive are equally effective in maintaining brackets clinically. Inexperienced operators had an overall 7.5% bond failure 12 months following bracket placement.

Acrylic Resins↗
PubMed2001

Quantum mechanical quantitative structure activity relationships to avoid mutagenicity in dental monomers.

The objective of this study was to identify through quantum mechanical quantitative structure activity relationships (Q-QSARs) chemical structures in dental monomers that influence their mutagenicity. AMPAC, a semiempirical computer program that provides quantum mechanical information for chemical structures, was applied to three series of reference chemicals: a set of methacrylates, a set of aromatic and a set of aliphatic epoxy compounds. QSAR models were developed using this chemical information together with mutagenicity data (Salmonella TA 100, Ames Test). CODESSA, a QSAR program that calculates quantum chemical descriptors from information generated by AMPAC and statistically matches these descriptors with observed biological properties was used. QSARs were developed which had r2 values exceeding 0.90 for each study series. These QSARs were used to accurately predict the mutagenicity of BISGMA. a monomer commonly used in dentistry, and two epoxy monomers with developing use in dentistry, GY-281 and UVR-6105. The Q-QSAR quantum mechanical descriptors correctly predicted the level of mutagenicity for all three compounds. The descriptors in the correlation equation pointed to components of structure that may contribute to mutagenesis. The QSARs also provided 'dose windows' for testing mutagenicity, circumventing the need for extensive dose exploration in the laboratory. The Q-QSAR method promises an approach for biomaterials scientists to predict and avoid mutagenicity from the chemicals used in new biomaterial designs.

Dental Enamel↗
PubMed2000

Reasons that orthodontic faculty teach and consider leaving teaching.

To assess reasons why orthodontic faculty consider leaving academia, a pretested questionnaire was mailed to 200 full-time (FT) and 200 part-time (PT) faculty randomly selected from the United States and Canada. A total of 144 (72 percent) of FT and 120 (60 percent) PT responded. About 38 percent FT and 25 percent PT were currently considering leaving academia. The average age of each group was about fifty years. Although significant differences were found in fifteen factors affecting the decision to leave, three factors ranked as most important (means> or =3.4) for FTs: salary support, financial support of department, and control over work or destiny. The three factors most important (means>3. 1) for PTs were: challenge of private practice, family commitments, and personal. FT and PT were similar in the most important and least important factors influencing their initial reasons to teach and satisfaction in teaching. However, the reasons why FT considered leaving were work related, while the PT's reasons were more personal. With the current shortage of FT orthodontic faculty becoming imminently greater, it appears that work-related issues could be addressed directly by administration.

Adult↗
PubMed1989

An evaluation of the Minnesota Multiphasic Personality Inventory as a discriminator of primary organic and primary psychogenic impotence in diabetic males.

The ability of the MMPI to discriminate between primary psychogenic impotence and primary organic impotence in males with diabetes mellitus was assessed. In order to provide the MMPI with the optimal situation to discriminate between the two groups, we attempted to form a homogeneous sample in terms of physical conditions. Thirty impotent diabetic males were classified as primary organic or primary psychogenic based on nocturnal penile tumescence data. Beutler et al.'s MMPI decision rules yielded a 63% misclassification of the two groups. Possible explanations for the lack of discriminative power of the MMPI with this sample of diabetic males were discussed in relation to previous findings. The power of nocturnal penile tumescence to classify men as having primary organic or primary psychogenic impotence was examined with reference to other vascular and endocrine variables.

Adult↗
PubMed1981

Paralumbar muscle activity in chronic low back pain.

Muscle spasm is often considered to be a prominent feature operating in chronic low back spin syndrome (LBP). The present study compared levels of paralumbar muscle activity, determined by an electromyogram (EMG), for LBP patients and normal subjects during periods of rest and voluntary muscular contraction. The resting state EMG measure did not differ in the 2 groups. However, when attempting to relax the low back while contracting other muscle groups, LBP patients exhibited higher mean levels of low back muscle activity as compared to the non-pain group. These results would suggest that such "cocontraction relaxation" procedures may provide a viable behavioral technique for assessing and possibly treating functional backache thought to be symptomatic of muscle spasm. Previous studies employing feedback and progressive relaxation techniques have trained subjects to reduce muscle tension in the resting state. Results of the present study suggest that the acquisition of "resting level" relaxation may be of little benefit to patients who exhibit excessive muscular tension while performing daily tasks. Rather, to maximize the likelihood of beneficial results, training would be better directed at relaxation of the low back during activity of other muscle groups.

Adult↗
PubMedDate not supplied

The effect of personal protective equipment on high-and low-dental fear patients.

PURPOSE: This investigation was designed to examine both high- and low-dental-fear patients' perceptions about and anxiety responses to personal protective equipment (PPE) as presented in a videotaped, simulated interaction between oral healthcare worker and patient. METHODS: Sixty-two individuals representing a convenience sample presented at the University of Missouri-Kansas City (UMKC) Dental School and were screened for eligibility. The Dental Fears Survey was administered to participants to assess level of dental fear. Subjects were then matched according to fear level, gender, and age, and randomly assigned to an experimental or control group. Subjects viewed a videotaped vignette of a male dentist conducting a new patient interview. The control group viewed a tape in which the provider did not utilize PPE. The experimental group viewed the provider putting on PPE at completion of the interview. Subjects were instructed to complete a semantic differential scale at completion of the tape in order for the researchers to assess their attitude toward the scene. Paired adjectives in the semantic scale were scored from 1 to 7, with low scores reflecting negative evaluations and high scores reflecting positive evaluations. Heart rate and skin conductance were measured prior to and during the viewing of the videotapes by means of a photoplethysmograph and an electrodermograph, respectively. RESULTS: A two-factor ANOVA found the main effect of fear to be significant (p < .05), with subjects exhibiting high levels of dental fear rating both videotapes (PPE & NO PPE) more negatively than subjects exhibiting low levels of dental fear. A repeated measure ANOVA was used for analysis of heart rate and skin conductance. The Dunn's Multiple Means Comparison Test showed that skin conductance increased significantly (p < .05) in both groups from baseline to presentation of the oral healthcare environment. CONCLUSIONS: A videotaped presentation of the dental environment produced significantly more negative evaluations from patients with high fear than from patients with low fear. Both groups experienced a significant increase in skin conductance (perspiration) upon presentation of the oral healthcare environment. However, presence of PPE did not adversely affect patient perceptions of the oral healthcare provider.

Adolescent↗