Daniel E. Tira

Prediction of maxillary canine impaction using sectors and angular measurement

Maxillary canine impaction has an incidence of 1 in 100 in the general population and has been reported as much higher in an individual orthodontic practice. Because patients with canine impactions generally have longer treatment times, depending on the location of the impacted tooth, early identification of impaction is of critical interest to the orthodontist. Sector location and angulation of the unerupted tooth have been analyzed previously as predictors of canine eruption after deciduous extraction. Additionally, sector location has been studied as an indicator of eventual impaction, resulting in good predictive success. In this study, angulation of the unerupted tooth was measured from panoramic radiographs and added to sector location to see whether the combination of these factors could predict impaction more accurately than sector alone. Results verified earlier findings for sector: canines that become impacted will overlap the adjacent lateral incisor in 82% of cases. Logistic regression analysis also determined that once the canine overlaps the midline of the lateral incisor, there is a greater than 0.87 chance of impaction. Sector was found to be the better predictor of impaction, with angulation adding little supplementary predictive value.

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.

Characteristics of Salivary Diffuse Infiltrative Lymphocytosis Syndrome in West Africa Human Immunodeficiency Virus-Associated Salivary Ductal Epithelial Atypia?

OBJECTIVE To determine the prevalence of diffuse infiltrative lymphocytosis syndrome (DILS) in the minor salivary glands of 30 African Cameroonian adults with the acquired immunodeficiency syndrome (AIDS). DESIGN Salivary gland tissue was analyzed using a modified classification system that was developed to aid the diagnosis of Sjögren syndrome. The advantages and disadvantages of this approach are discussed. MATERIALS AND METHODS Formalin-fixed, paraffin-embedded, hematoxylin-eosin-stained biopsy sections were prepared for 30 patients with AIDS, 26 healthy individuals who declined human immunodeficiency virus (HIV) testing, and 4 seronegative healthy controls. Tissues were immunostained for CD4/CD8+ lymphocytes and cytomegalovirus (CMV), and transmission electron microscopy was performed to locate viral particles. Patients were tested for HIV-1 and HIV-2 by the HIV/Chek System 3 or CAMSTIX-HIV-1 and HIV-2 assay. RESULTS Severe salivary ductal atypia (96%) was the feature most strongly associated with AIDS, and the lymphocytic focus score was the second histologic feature most strongly correlated with AIDS. Forty-eight percent of patients with HIV-1 infection had more than 1 lymphocytic focus in a minor salivary gland. These lymphocytes were primarily CD8+. We report, to the best of our knowledge, the first case of multinucleated salivary duct epithelial cells in minor salivary glands also containing enveloped virus particles. All cases were negative for CMV. CONCLUSIONS The prevalence of DILS in West Africans with AIDS appears higher than the prevalence reported in whites from the United States and Europe and in blacks from the United States, a group that has been reported to have a greater incidence of DILS than whites. This discrepancy may be related to differences in patient selection criteria. The determination of lymphocytic focus score, as used in the diagnosis of Sjögren syndrome, with the adjunct of ductal atypia is useful for assessing DILS. The impact of patient selection, drug therapy, and parasites on salivary gland pathology is discussed.

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.

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.

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.

A computer-based dental diagnostic case simulation (DDS) system.

Abstract The Dental Diagnostic Simulation (DDS) System is designed to generate basic dental case studies for presentation in an interactive, computerized fashion. A case so generated is organized into information gathering and diagnosis sections with six potential areas of inquiry and ten potential stages of diagnosis available for incorporation in the case. To develop such a case, a case author need only supply patient responses to questions, state laboratory test results, and identify correct diagnoses as outlined in a Case Author Workbook . Program generation facilities (macros) of DDS are then used to produce the program code with respect to the outlined case.