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Biomedical subjects

J D Eick

Publications and source records attributed to J D Eick.

At least 73 records · Page 4Linked to original sources
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 dentinal surface: its influence on dentinal adhesion. Part I.

Three categories of dentinal adhesive are proposed: category I includes adhesives with shear bond strength values between 5 and 7 MPa; category II includes dentinal adhesives with shear bond strengths between 8 and 14 MPa; and category III includes adhesives with shear bond strength values up to 20 MPa. In part I of this article, photomicrographs of the dentinal smear layer and three category I first-generation dentin-adhesive interfaces are presented. The photomicrographs show that the wetting and penetration of the first-generation dentinal adhesives were not adequate to produce high shear bond strengths. When the category I adhesives were tested for shear bond strength, failures occurred at the interface or in the resin adhesive. Future articles will explain wetting and adhesive performance of category II and III adhesives.

Acrylic Resins↗
PubMed1991

The effect of storage and thermocycling on the shear bond strength of three dentinal adhesives.

The purpose of this investigation was to evaluate the effects of time of storage and thermocycling on the shear bond strength of three dentinal adhesives. The shear bond strength of Mirage Bond was significantly greater than that of Scotchbond 2, which was significantly greater than that of Scotchbond Dual Cure (P less than or equal to .05). Thermocycling significantly lowered the shear bond strength of Scotchbond Dual Cure and Scotchbond 2, but not that of Mirage Bond (P less than or equal to .05). Time of storage did not affect the shear bond strength of the other adhesives, but Mirage Bond had a significantly greater shear bond strength after 1 month of storage (P less than or equal to .05). Scanning electron microscopic observations showed that the fracture patterns were all at the smear layer-adhesive interface for Scotchbond Dual Cure, the majority of the fractures were at the primer-adhesive interface for Scotchbond 2, and most of the fractures were cohesive in the bonding agent for Mirage Bond.

Analysis of Variance↗
PubMed1990

Marginal fit of porcelain-fused-to-metal and two types of ceramic crown.

The marginal fit of Dicor, Cerestore, and porcelain-fused-to-metal crowns was evaluated. Ten premolars free of caries were prepared for each type of restoration and crowns were made. The vertical marginal openings were measured before cementation, after cementation, and after thermocycling. There were statistically significant differences between all three test conditions in each type of crown, between Dicor and porcelain-fused-to-metal crowns after cementation and after thermocycling, and between Cerestore and porcelain-fused-to-metal crowns after thermocycling. All 30 cemented crowns were then embedded in acrylic resin for serial sections for measurement of absolute marginal openings. Statistically significant differences between Dicor and Cerestore crowns and between Cerestore and porcelain-fused-to-metal crowns were found. It was concluded that marginal openings increased after cementation and after thermocycling, and porcelain-fused-to-metal crowns had significantly better marginal fit than that of Dicor and Cerestore crowns.

Aluminum↗
PubMed1990

Mechanical behavior of mandibular continuity defects reconstructed using combinations of hydroxylapatite and autogenous bone.

The purpose of this investigation was to determine the mechanical behavior of primate (Macaca mulatta) mandibles with continuity defects reconstructed using varying ratios of an alloplastic hydroxylapatite (HA) implant material mixed with autogenous bone (AB). The defects were allowed to heal for 6 and 18 months before killing the animals and mechanical testing. Each animal had one side of the mandible restored with 100% AB as control. The fracture strength and section modulus of the opposite side of the mandible, containing the test ratio of HA-AB, were directly compared with the mechanical behavior of the control side. The fracture strength and section modulus were evaluated by a cantilever type of mechanical test that took into account the anisotropic, viscoelastic, and geometric nature of the mandible. The type of bone and tissue at the fracture site was examined by scanning electron microscopy and a direct correlation between the amount of bone and/or fibrous tissue growth around the HA implant material and the fracture strength and section modulus values was established. The average fracture strength of the AB graft sites at 18 months was 9,975 +/- 4,300 psi, with ratios of 25:75 and 50:50 HA-AB giving test results approaching those of the AB graft sites.

Alveolar Ridge Augmentation↗
PubMed1990

Restoration of mandibular continuity defects using combinations of hydroxylapatite and autogenous bone: microscopic observations.

The purpose of this investigation was to assess by light, transmission, and scanning electron microscopy the healing of mandibular continuity defects reconstructed with varying ratios of an alloplastic hydroxylapatite implant material (HA) mixed with autogenous bone (AB). This study reports the microscopic observations of implant and control sites at 6 and 18 months postsurgery. The results confirm the biocompatibility of dense HA granules. Specimens exhibited differing degrees of osseous regeneration that appeared related to the percent composition of HA. At 18 months, 86% and 91% of the HA granules were completely surrounded by bone in those specimens reconstructed with implants consisting of 25% and 50% HA, respectively. In contrast, specimens receiving implants consisting of 75% and 100% HA features osseous encapsulation of 75% and 66% of the granules, respectively. The results of this limited study indicate that dense HA granules mixed with AB in ratios ranging from 3:1 to 1:1 (AB:HA) may be successfully used as a bone extender during reconstructive surgery.

Animals↗
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↗
PubMed1990

Fracture strength of Class I versus Class II restored premolars tested at the marginal ridge. 2. Cavosurface bonding and cavosurface plus internal enamel bonding.

The purpose of this study was to test the difference between the strength of the marginal ridge of extracted teeth with a Class I composite resin restoration and the strength of the marginal ridge of teeth with a Class II amalgam restoration with retention grooves. A statistically significant difference in fracture strengths was found among groups. No statistically significant difference was found among restored preparations, beveling technique, and restorative material. Statistically significant differences in fracture strength were found between the whole tooth group and treatment groups; between the whole tooth group and Class II amalgam restoration group; and between the unrestored tooth preparation group and all other tooth groups.

Acid Etching, Dental↗
PubMed1990

The effect of time on the adhesion of light-body to heavy-body Express in the two-step reline polyvinylsiloxane impression technique.

Often times light-body wash (LB) cannot be added to the heavy-body putty (HB) within 30 minutes when utilizing the two-step reline impression technique. The purpose of this study was to add the LB to the HB at times greater than 30 minutes and test the tensile bond strength. A split aluminum mold which created a bonding area of 1.13 cm2 and tray were filled with Express HB. After HB set the Express LB in a tray was added at varying times. The split molds were then separated and samples tested on the Instron. Ten groups with five samples/group (determined by a pilot study) were made. The times which the LB was added to the set HB and tested were: A) Immediately (one-step procedure); B) 10 minutes and contaminated with saliva (negative control); C) 10 minutes; D) 30 minutes; E) 45 minutes; F) 1 hour; G) 3 hours; H) 24 hours; I) 115 hours; and J) Freshened after 3 months. The results of this study indicate that saliva-contaminated samples were weaker than all other groups (P less than or equal to 0.01) and as far as tensile bond strength between materials is concerned, there appears to be no detrimental effect in tensile bond strength between HB and LB when delaying the application of the light-body material (P less than or equal to 0.01).

Dental Bonding↗
PubMed1990

A scanning electron microscopic study of the effect of air polishing on the enamel-sealant surface.

The purpose of this study was to evaluate the enamel-sealant interface following the use of standard sealant placement techniques and an air-polishing system. Twenty-five caries-free premolars were extracted and stored in distilled water for 2 days. Five teeth were randomly assigned to each of five treatment groups. The occlusal surface was (1) air polished for 20 seconds, (2) cleaned with pumice for 20 seconds, or (3) not cleaned. Following treatment, 35% orthophosphoric acid was applied for 60 seconds. In two control groups, the acid-etching procedure was eliminated, and one group (4) was air polished for 20 seconds, while the other group (5) was not cleaned. Tinted self-curing sealant was applied to the entire occlusal surface of each tooth. Following the treatment, scanning electron photomicrographs were taken at X 1000 magnification. To evaluate the enamel-resin interface, the number of resin tags were counted by one precalibrated rater. A statistically significant difference was found among the treatment groups and the control groups. Air polishing combined with acid etching resulted in an improved surface for resin wetting as determined by the number of resin tags formed; however, the differences among the treatment groups were not large enough to be statistically significant.

Acid Etching, Dental↗
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

Effect of systemic fluoride on rat molar morphology. Stereophotogrammetric analysis.

Female Sprague-Dawley rats were divided into three groups. All three groups were given the same solid diet (with 1.6 ppm F). Group I was given deionized water, group II drank water with 5 ppm fluoride added, and group III had 50 ppm fluoride added. All females were mated with the same male. The pups were sacrificed at 28 days, and the mandibles were removed and cleaned. Three-dimensional representations of the occlusal surfaces of the 1st and 2nd mandibular molars were reproduced via computer-digitized images using stereophotogrammetry. Fissure depths and widths were measured, and 'volumes' of the fissures were computed. The fissure widths, depths, and volumes were compared statistically using unpaired t tests between groups (p less than 0.05). There were significant differences in fissure depth between groups I and II and between groups I and III. For fissure volumes, significant differences were found between groups I and III. The width of the fissure and the overall tooth size were not significantly different between fluoride-treated groups. Standardization showed a reproducibility to within +/- 40 mm with the stereophotogrammetric method.

Animals↗
PubMed1989

The effectiveness of two sonic and two ultrasonic scaler tips in furcations.

This study compared the effectiveness of two sonic and two ultrasonic scaler tips on artificial calculus removal from the furcations of mandibular first and second molars. Twenty-four extracted mandibular molars were cleaned and randomly assigned to one of four treatment groups. Teeth were split buccal lingually, artificial calculus was placed in the furcation areas, and the teeth were photographed with a stereo camera. Teeth were reconnected with bonding material and mounted in a typodont with simulated gingiva and attached to a dental chair. Teeth were instrumented with either a Cavitron TFI10 tip, Cavitron EWPP tip, Titan-S Universal tip, or Titan-S Sickle tip by a licensed dental hygienist until each tooth was judged calculus free to the touch with a CH3 explorer. Time for each instrumentation period was recorded. Following instrumentation, the teeth were again split and photographed. Stereophotogrammetry was used to produce tracings of the teeth with initial calculus and remaining calculus. Pre-instrumentation and post-instrumentation amounts of calculus on the surface area were computed using the Bioquant system. A two factor analysis of variance was conducted followed with a Newman-Keuls Multiple Comparison Technique to test for within and between differences. Significant differences (P less than or equal to 0.01) were found between pre- and post-amounts of calculus for all tips. No significant differences (P less than or equal to 0.05) were found between the four instrument tips with respect to percentage of furcation surface with calculus remaining. No differences were found between tips with regard to the time required to clean the test surfaces.

Dental Calculus↗