Biomedical subjects

D E Tira

Publications and source records attributed to D E Tira.

At least 19 recordsLinked to original sources

PubMed1999

An evaluation of factors affecting duration of orthodontic treatment.

One of the first questions asked by new orthodontic patients is: How long will I need to wear my braces? A multitude of factors have the potential to influence the answer to this question. The purpose of this retrospective study was to identify some of the primary factors that influence orthodontic treatment duration. Few studies have attempted to evaluate these factors. Data were gathered from 140 consecutively completed, comprehensive treatment patient records in five orthodontic offices. Thirty-one variables related to patient characteristics, diagnostic factors, modality of treatment, and patient cooperation were evaluated. Average treatment time was 28.6 months with a range of 23.4 to 33.4 months among the five offices. Nearly half (46.9%) of the variation in treatment duration was explained by a five-step multiple regression analysis. Included in the regression equation were the number of missed appointments, the number of replaced brackets and bands, the number of treatment phases, the number of negative chart entries regarding oral hygiene, and the prescription of headgear wear during treatment. An additional 6.7% of the variance was explained by variation among the five offices. Six of the 31 variables examined made a statistically significant (alpha =.01) contribution to the explanation of variation in treatment time. The quality of the finished cases and the appropriateness of the original diagnosis and treatment plan were not evaluated. Developing an objective assessment to evaluate these areas may be important for increasing our understanding of treatment time variation.

Adolescent↗

PubMed1999

Time management behaviors as potential explanatory factors in dental academic achievement.

DAT scores and predental GPAs have made the greatest but an imperfect contribution to the reliable estimation of dental students' academic success. One variable unaddressed yet having potential in accounting for unexplained variability in dental school performance is time management behaviors (TMB), a multidimensional attribute that is critical to success in a dental curriculum. Research has indicated a relationship of TMB dimensions (Setting Goals and Priorities, Mechanics of Time Management, Preference for Organization) with undergraduate academic achievement. The purposes of this study were: 1) to ascertain the levels of TMB dimensions reflected in predental students; 2) to validate in predental students the relationship of TMB dimensions and undergraduate academic achievement; and 3) to explore the relationship of TMB dimensions of predental students as explanatory variables of their early academic achievement in the dental curriculum. All individuals who were applicants interviewed for the 1997 entering D.D.S. class and the majority of members of the 1996 entering D.D.S. class participated in this study (n = 192). Each completed the TMB scale. High levels of TMB across dimensions were observed in predental and dental students. Unlike prior research, results showed virtually no relationship of TMB dimensions with undergraduate GPA of these subjects. Though a small relationship was found between dimensions and first-year dental GPAs, no dimension explained a significant amount of variance in any of these dental GPAs beyond that of undergraduate science GPA.

Achievement↗

PubMed1998

The effects of different storage conditions on polyether and polyvinylsiloxane impressions.

While being shipped to a laboratory, impressions can be exposed to excessive temperatures. This study compared the effects of different time and temperature storage conditions, including temperature extremes of 66 C and -10 C, on the accuracy of addition silicone and polyether impressions. The greatest distortion generally occurred as a result of the 66 C temperature extreme. The authors recommend that impressions be poured in stone according to manufacturers' specifications before being shipped to a dental laboratory.

Calcium Sulfate↗

PubMed1993

Glycosaminoglycans and periodontal disease: analysis of GCF by safranin O.

The purpose of this study was to quantify glycosaminoglycans (GAG) released into the gingival crevicular fluid (GCF) during health, gingivitis, and adult periodontitis. The investigation tested the hypothesis that increased amounts of GAG can be measured in GCF associated with gingivitis and adult periodontitis as compared to health. An individual patient's sampling sites were assigned to either a health (control) group or 1 of 3 experimental groups, gingivitis, periodontal "maintenance" (perio-M), or periodontal "non-maintenance" (perio-NM) according to standard clinical criteria of pocket probing depth, bleeding on probing, and radiographic evidence of bone loss. The perio-M group was defined as a periodontal patient who had received a dental prophylaxis and/or root planning within 6 months prior to GCF collection. The perio-NM group had received no periodontal therapy during the previous 6 months. Subsequent to air-drying and isolation, GCF was collected by a microcapillary pipette held at the gingival margin. All fluid samples were digested overnight at 37 degrees C with 25 micrograms of papain and analyzed for GAG content using a chondroitin-4-sulfate standard. Data generated from safranin "O" dye binding assays of GAG revealed 4.41 +/- 9.82 ng GAG from the health (control) group (n = 23); the gingivitis group (n = 13) showed 15.23 +/- 11.85 ng GAG/sample; perio-M group (n = 11) showed 23.64 +/- 12.98 ng GAG/sample and the perio-NM group (n = 12) exhibited 119.08 +/- 33.14 ng GAG/sample.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Clinical assessment of the INTERPLAK toothbrush vs a conventional brush plus floss.

Thirty clinical recall patients from the University of Missouri at Kansas City School of Dentistry participated in a 4-week study to determine the long-term effectiveness of the INTERPLAK Home Plaque-Removal Instrument compared to manual brushing and flossing. Patients were divided into two groups, with each group using the INTERPLAK device for 2 months and the manual brush for 2 months. Patients were assessed according to measured indices for plaque, bleeding, crevice depth, and calculus. The study found that both kinds of brushes significantly reduced plaque, bleeding, and crevice depth; however, only the INTERPLAK brush reduced calculus. Improvements on all indices were greater for the INTERPLAK device than they were for manual brushing and flossing. At the end of the 4 months, most patients indicated that they would continue to use the INTERPLAK device.

Adult↗

PubMed1993

Clinical and cost effectiveness of the counter-rotational brush in private practice.

There have previously been no studies on the cost effectiveness of the use of a counter-rotational toothbrush (INTERPLAK Home Plaque-Removal Instrument), which has been demonstrated to be more effective than ordinary toothbrushes in reaching plaque-removal and gingival-health goals. Killoy et al studied the costs of required periodontal treatment for 32 patients with moderate periodontitis at two corporate capitation dental centers. The subjects were divided into two groups, a test group that brushed with a counter-rotational toothbrush and one that brushed with a manual toothbrush. Probing depth, attachment levels, and plaque and bleeding indexes in the test brush group were better than those in the control group. The end result was a mean reduction of $535 in the cost of periodontal treatment that had been planned before using the counter-rotational brush over 18 months, while the group using the manual brush experienced a mean increase of $11 in required treatment over original plans. Furthermore, the test group reached a state of gingival health, but the control group did not. The study concluded that the counter-rotational brush is cost effective.

Analysis of Variance↗

PubMed1992

Effect of two dentin bonding agents on microleakage in two different cavity designs.

Studies have shown that cavity design and dentinal bonding agents can affect composite resin microleakage. This study compared the microleakage at cementum-dentin margins of box- and Vshaped preparations restored with two different bonding agents. Twenty freshly extracted, human third molars were prepared with one box-shaped and one V-shaped preparation on the mesial or distal surface. Occlusal margins were terminated in etched enamel and gingival margins were in cementum-dentin. There was no statistically significant difference (p greater than 0.05) between Dual Cure Scotchbond and Scotchbond 2 samples restored in the box-shaped preparations, but Scotchbond 2 had statistically significantly less microleakage (p less than 0.05) than Dual Cure adhesive in V-shaped preparations. The sealing of dentinal bonding agents varied in different cavity designs.

Adhesives↗

PubMed1992

Accuracy of one-step versus two-step putty wash addition silicone impression technique.

This study compared the accuracy of one-step putty wash with two-step putty wash impression techniques. Five addition silicone impression materials-Mirror 3 (MR), Mirror 3 Extrude (ME), Express (E), Permagum (P), and Absolute(A)--were tested. A stainless steel model containing two full-crown abutment preparations was used as the positive control. Five replications for one-step and two-step putty wash impressions of the master model were made for each test material. Accuracy of the materials was assessed by measuring six dimensions on stone dies poured from impressions of the master model. Accuracy of addition silicone impression material is affected more by material than technique. Accuracy of the putty wash one-step impression technique was not different from the putty wash two-step impression technique except at one of the six dimensions where one-step was more accurate than two-step. Mirror 3 putty wash two-step impression presented less distortion than Mirror 3 Extrude putty wash one-step or two-step impression.

Analysis of Variance↗

PubMed1991

Stereophotogrammetric analysis of abutment tooth movement in distal-extension removable partial dentures with intracoronal attachments and clasps.

This study applied the three-dimensional measurement technique of stereophotogrammetry to measure abutment tooth movement under occlusal loading as a function of intracoronal attachment and clasp design. Six distal-extension removable partial denture designs were studied: (1) RPI-mesial occlusal rest, proximal plate, buccal I-bar; (2) cast circumferential clasp; (3) P.D. locking semiprecision attachment; (4) Thompson dowel nonlocking semiprecision attachment; (5) McCollum precision attachment; and (6) Stern G/L precision attachment. The movement in microns was determined by computer analysis. The Thompson dowel semiprecision attachment generated the most abutment movement in a gingival direction. The clasp-retained designs generally had less total movement than the attachment designs. Clasps and attachments for the abutment teeth adjacent to the distal-extension bases generally moved more than the abutment teeth.

Analysis of Variance↗

PubMed1991

Comparison of two-surface and multiple-surface scoring methodologies for in vitro microleakage studies.

Investigators differ on the use of a two-surface or multiple-surface scoring methodology in sectional microleakage studies. This study compared microleakage scores using both two-surface and multiple-surface scoring methods for two preparation types and two different dentin bonding agents. Twenty freshly extracted molars each received one box-shaped and one V-shaped restoration on the mesial or distal surface. Each restoration was cut occlusogingivally into four sections, yielding eight surfaces for scoring. Surfaces were marked to identify central (I), lateral (II), and end (III) locations, then scored by two calibrated raters. The Wilcoxon Matched-Pairs Signed-Rank Test showed a statistically significant difference (p less than or equal to 0.05) in median microleakage scores obtained by an end two- surface and multiple-surface evaluation for V-shaped preparations restored with Scotchbond 2, P-50. No other statistically significant comparisons were detected. Results suggest that microleakage may be more extreme at end surfaces and that these end surfaces should be scored so that an accurate microleakage value could be assigned to composite restorations.

Analysis of Variance↗

PubMed1991

The effectiveness of a counterrotational-action power toothbrush on plaque control in orthodontic patients.

This study compared counterrotational-action power toothbrushing with manual toothbrushing in effectiveness on plaque control and gingival health in 20 randomly selected orthodontic patients at the University of Missouri-Kansas City. A blind two-group crossover design was used. Gingival and plaque scores were recorded, and a prophylaxis was given to bring the plaque score to zero. Ten subjects received counterrotational power brushes, and ten subjects received manual brushes. Instructions appropriate to each brushing method were given by a hygienist. At 30 and 60 days, plaque and gingival scores were recorded and a prophylaxis was given. At 60 days the subjects who were using power brushes were switched to manual brushes, and the subjects who were using manual brushes were switched to power brushes. At 30 and 60 days, plaque and gingival scores were recorded and a prophylaxis was given. Plaque and gingival scores were significantly less (p less than 0.01) after brushing 2 months with the counterrotational power brush than with the manual brush. This finding was irrespective of the sequence in which the brushes were used.

Adolescent↗

PubMed1991

Use of monoclonal antibodies to enumerate spirochetes and identify Treponema denticola in dental plaque of children, adolescents and young adults.

Identification of spirochetes in dental plaque is difficult. Not all spirochetes can be cultured and microscopic analysis based on darkfield or phase optics cannot determine the genus and species of individual bacterial cells. The purpose of this study was to use monoclonal antibodies in an immunoenzyme technique to stain spirochetes in dental plaque. Separate mAb were used to estimate total spirochetes and relative numbers of 2 distinct types of Treponema denticola. Plaque samples were collected from 40 subjects grouped by age. Results showed that older subjects are more likely to have spirochetes, to have more spirochetes and to have more diverse populations or spirochetes than younger subjects. Our studies suggest that T. denticola may be the first treponeme to colonize the primary dentition, that T. denticola appears to comprise a major proportion of all spirochetes at all ages and that two distinct serotypes of T. denticola are found to coexist in plaque from most children.

Adolescent↗

PubMed1990

Fracture strength of Class I versus Class II restored premolars tested at the marginal ridge. I. Standard preparations.

Two groups of maxillary premolars with Class I cavities were prepared with one marginal ridge thickness to a width of 1.0 mm. One group was restored with amalgam and the other group with composite resin. Two groups of Class II cavities also were prepared and restored with amalgam and composite resin. The teeth in the four treatment groups were subjected to a centric load at the marginal ridge until fracture occurred. A two-factor analysis of variance revealed a statistically significant difference between the class of preparation (Class I preparations were weaker than were Class II preparations) but differences in strength between restorative materials (composite resin versus amalgam) and the interaction effect (class of preparation x restorative materials) were not found to be statistically significant (alpha = .05). A Newman-Keuls sequential range test found no statistically significant differences in strength between groups (alpha = .05). Fracture patterns were observed under scanning electron microscope. Fractures extended into the enamel and into the material in the Class I composite resin, Class I amalgam, and Class II composite resin restorations. Fractures extended only into the material in Class II amalgam restorations.

Bicuspid↗

PubMed1989

The effects of rinse volumes and air and water pressures on enamel-composite resin bond strength.

To assess the effect of different rinse volumes and air and water pressures on shear enamel-composite resin bond strength, the buccal surfaces of 384 maxillary molars were prepared through 600-grit silicon carbide, gel-etched, and rinsed with one of 24 randomly assigned test conditions: 0, 2, 5, 10, 15, or 25 ml volume wash with air and water syringe pressures of 20/10, 20/40, 40/10, or 40/40 psi. The rinsed enamel was dried, Scotchbond adhesive was applied, and a polysiloxane ring was secured to the flattened surface. Silux resin was incrementally added to a depth of 2 mm and each increment cured 40 seconds. Shear bond strengths were determined by using an Instron testing machine at a crosshead speed of 0.5 mm/min. A statistically significant (p less than 0.05) volume effect was found only between the 0 volume rinse groups and each other volume group. No statistically significant differences (p less than 0.05) were seen between air or water pressure groups. Mean bond strengths for greater than or equal to 2 ml rinsing ranged from 250 +/- 30 to 280 +/- 50 kg/cm2. Enamel-composite resin bond strengths were not significantly increased beyond 2 ml rinsing regardless of air and water syringe pressure used.

Air↗

PubMed1989

The effect of 2% chlorhexidine digluconate irrigation on clinical parameters and the level of Bacteroides gingivalis in periodontal pockets.

Eight patients with moderate periodontitis volunteered to participate in a study to assess the effect of subgingival 2% chlorhexidine irrigation, with and without scaling and root planing, on clinical parameters and the level of Bacteroides gingivalis in periodontal pockets. Each quadrant was required to have at least one site with a probing depth of 6 mm or greater and bleeding on probing. The patients were treated following a randomized four quadrant design: one quadrant received no treatment; a second quadrant received scaling and root planing only; a third quadrant received chlorhexidine irrigation only; the fourth quadrant received scaling and root planing, plus chlorhexidine irrigation. Sites to receive chlorhexidine were irrigated at 0, 1, 2, and 3 weeks. Clinical and microbiological indices were measured and recorded at 0, 5, 7, 11, and 15 weeks. The clinical parameters measured included; Plaque Index (PI), Gingival Index (GI), probing depth (PD), Bleeding Tendency (BT), and attachment level (AL). The attachment level was measured using an occlusal stint as a fixed reference point. The level of Bacteroides gingivalis was measured by labeling the plaque sample with a polyclonal fluorescent antibody. The plaque smear was then read using a fluorescent microscope at 1000 magnification. The Spearman Rank-Order Correlation was used to determine the relationship between parameters at baseline. The effects of the treatment groups were compared using the Neuman-Keuls Multiple Comparison Technique. The results showed that a positive correlation existed between B. gingivalis (rs = 0.68) and Bleeding Tendency and between P1I (rs = 0.77) and GI.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1989

The effectiveness of a counter-rotary action powered toothbrush and conventional toothbrush on plaque removal and gingival bleeding. A short term study.

Initial investigations have demonstrated the effectiveness of a new contra-rotary powered electric toothbrush in removing plaque supragingivally, subgingivally, and interproximally following a single use. The purpose of this study was to evaluate the effectiveness of a counter-rotary toothbrush following 1) one time instruction, 2) reinstruction and 1 week practice; and 3) a third instruction and 3 weeks of practice and home use. Twenty-four patients were studied; 12 using the counter-rotary toothbrush and 12 using a conventional toothbrush. Using O'Leary and Turesky plaque indices, both brushes significantly reduced supragingival plaque from baseline at all intervals. The counter-rotary brush, however, was more efficient than the conventional brush at all intervals (P less than 0.01). Using a Surface Area Plaque Index, both brushes significantly reduced supragingival plaque from baseline at all intervals but there were no significant differences between brushes. A timed bleeding index showed significant reduction in gingival bleeding following 28 days of brushing with both brushes. Again, the counter-rotary toothbrush was superior to the conventional toothbrush (P less than 0.01).

Dental Plaque↗

PubMed1989

The effect of experimental stress and experimental occlusal interference on masseteric EMG activity.

This experiment attempted to study the separate and combined effects of occlusal interference and transient stress on masseteric activity among eight nonclinical human subjects. Before each of two sessions, subjects were fitted with an occlusal interference or an occlusally inert (control) molar clasp. During each session they viewed horrific and idyllic videotapes while masseter EMG was recorded bilaterally. Electrodermal measures validated that the horrific videotapes were stressful. Studies showed that the occlusal variable worked less well. The EMG was elevated contralateral to both clasps and during videotape viewing. The EMG effects from videotape viewing were relatively pronounced without the occlusal interference. Research implications are discussed.

Adolescent↗

PubMed1989

Assessment of curette sharpness.

Nothing to date has appeared in the literature addressing the relationship of specific bevel dimension and clinical sharpness of curette blades. This study investigated the degree of clinical sharpness of Gracey curettes following four periods of simulated root planning and, using the scanning electron microscope (SEM), determined the approximate number of strokes at which loss of clinical sharpness became apparent. Seventy-five new stainless steel curette blades were standardized and randomly assigned to one of five groups: control, 30-stroke, 50-stroke, 70-stroke, and 90-stroke. With the exception of the control group, blades underwent a simulated root-planing procedure, on extracted, periodontally involved teeth, which employed a device to standardize pressure and stroke length. Blades were then tested for clinical sharpness using light reflection, with two degrees of magnification; and plastic stick, a tactile evaluation. Blades were photographed under the SEM at a magnification of x1,000. Bevel width was measured at 10 standardized locations on the photomicrographs, and a mean was calculated. Nonparametric data were analyzed using the Kruskal-Wallis statistical test and SEM parametric data using ANOVA and post hoc Newman-Kuels tests. Results showed no significant differences among treatment groups when either tactile or magnification sharpness tests were used. Analysis of the SEM data showed no statistically significant differences among bevel dimensions for any of the five groups. A Spearman rank order correlation, used to compare the clinical data to the SEM bevel measurements, showed no correlation of clinical sharpness and SEM-determined bevel dimension.

Dental Instruments↗