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Biomedical subjects

Edward J Swift

Publications and source records attributed to Edward J Swift.

17 recordsLinked to original sources
PubMed2003

Fracture resistance of prepared teeth restored with bonded inlay restorations.

STATEMENT OF PROBLEM: intact, prepared, and restored human maxillary premolars. MATERIAL AND METHODS: Fifty intact, noncarious human maxillary premolars were divided into 5 groups of 10 and were mounted with their roots imbedded in autopolymerized acrylic. In the first group, the teeth were intact with no preparation. In the other 4 groups, Class II MOD preparations were made with a water-cooled high-speed hand piece. In 1 group, the cavity preparations were restored with bonded CAD/CAM ceramic inlays. In 2 groups, the preparations were restored with bonded CAD/CAM composite inlays (acid etched or air particle abraded). In the final group, the teeth were prepared but unrestored. Specimens were tested individually in a universal testing machine, in which a 4.82-mm-diameter steel sphere plunger was mounted in the crosshead moving at 0.5 mm/min. The plunger contacted the facial and lingual triangular ridges beyond the margins of the restorations. Peak load to fracture (N) was measured for each specimen. Means were calculated and analyzed with analysis of variance (P</=.05). RESULTS: MOD preparations weakened the teeth by approximately 59%. Restoring the teeth with ceramic or composite inlays did not significantly strengthen the teeth under this testing system. Of the restored teeth, those restored with indirect composite inlays cemented following manufacturer's recommendations had the highest fracture resistance. CONCLUSION: Within the limitations of this study, under static compression load testing, bonded inlay restorations did not strengthen maxillary premolars with large MOD preparations.

Bicuspid↗
PubMed2003

Irradiance effects on the mechanical properties of universal hybrid and flowable hybrid resin composites.

OBJECTIVES: A potential problem with high-intensity lights might be failure of polymer chains to grow and cross-link in a desired fashion, thereby affecting the structure and properties of the polymers formed. The purpose of this study was to evaluate mechanical properties of resin composites polymerized using four different light-curing units. METHODS: A conventional quartz-tungsten-halogen (QTH) light, a soft-start light, an argon-ion laser, and a plasma-arc curing light were used to polymerize disk-shaped (9.0mm diameter x 1.0 mm high) and cylinder-shaped (4mm diameter x 8 mm high) specimens of a universal hybrid and a flowable hybrid composite. Biaxial flexure strength, fracture toughness, hardness, compressive strength, and diametral tensile strength were determined for each composite. RESULTS: The use of the plasma-arc curing light, a high-intensity light, resulted in significantly lower hardness for the universal hybrid composite compared with the hardness obtained using the conventional QTH and the soft-start units. Hardness was the only mechanical property that was adversely affected by the use of a high-intensity light. SIGNIFICANCE: High-intensity lights might affect some resin composite mechanical properties, but this effect cannot be generalized to all resin composites and all properties.

Composite Resins↗
PubMed2003

Perioesthetic approach to the diagnosis and treatment of carious and noncarious cervical lesions: Part I.

Several factors can contribute to the development of noncarious cervical lesions. Therefore, these lesions can be described and classified according to their primary etiology. Traditionally, most dentists have treated noncarious cervical lesions only with restorative methods, for example, composite resin restorations. However, in many cases, a periodontal or a combined restorative/periodontal approach provides a better esthetic and functional result. In part I of this two-part report, we provide a review of noncarious cervical lesions and a series of clinical case reports showing surgical techniques used and the importance of the periodontal aspect of lesion management.

Adult↗
PubMed2003

Dentin bonding.

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Dentin-Bonding Agents↗
PubMed2003

Repairability of a packable resin-based composite using different adhesives.

PURPOSE: To compare the repair potential of a packable composite (Filtek P60) to that of a conventional hybrid composite (Pertac II) using three different adhesives: an unfilled resin (EBS-Multi), a one-bottle, acetone-based adhesive (One-Step), and a self-etching adhesive (Prompt L-Pop). MATERIALS AND METHODS: 30 composite disks (diameter = 8 mm) of each composite material were fabricated, light-cured, and stored in 37 degrees C for 7 days. The specimens were polished to 600-grit, sandblasted (CoJet-System), silanated, and randomly assigned to three groups (n=10). EBS-Multi, One-Step, and Prompt L-Pop were applied to each composite and cured. Pertac II was applied in a #5 gelatin capsule and light-cured. As controls, Pertac II was applied to freshly cured Filtek P60 and Pertac II specimens, with no additional surface treatment. Specimens were loaded in shear using an Instron testing machine at a crosshead speed of 5 mm/minute, 24 hours after bonding, and the peak shear force at failure was converted to MPa (force/area). RESULTS: ANOVA showed a significant difference in means at P<0.001. Tukey's test was used for pairwise comparisons. Mean SBS (+/-SD, MPa) were: P60/control: 25.2 (3.0); P60/EBS-Multi: 18.0 (2.3); P60/One-Step: 16.7 (2.3); P60/Prompt: 10.5 (3.3); Pertac/control: 25.5 (3.6); Pertac/EBS-Multi: 18.8 (3.0); Pertac/One-Step: 18.8 (2.4); Pertac/Prompt: 9.7 (3.5). Repair strengths were all significantly less than their respective controls, and repairs made using Prompt L-Pop had significantly lower mean strengths than the repairs made with EBS-Multi and One-Step (P<0.05).

Adhesives↗
PubMed2002

LED curing lights.

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Composite Resins↗
PubMed2002

Capping the inflamed pulp under different clinical conditions.

BACKGROUND: A great deal of controversy exists regarding the reliability of capping the inflamed pulp. In particular, the use of calcium hydroxide as a capping agent has come into question. In this study, hard tissue barrier formation after inflamed pulps were capped directly or after partial pulpotomy was compared with calcium hydroxide or bonded resin and with no additional seal or an IRM surface seal. Seventy teeth in five dogs were used. Ten untreated teeth were used as negative controls. In 60 teeth, pulpal inflammation was induced by preparing a cavity close to the pulp and sealing a cotton pellet soaked in plaque in it for 1 to 2 weeks. The cavities were then re-entered and extended to expose the pulps. MATERIALS AND METHODS: In half the teeth (n = 30) a partial pulpotomy was performed and in the other half (n = 30) pulpal treatment was performed on the superficial exposed pulp. Both pulpal treatment groups received the same restorative procedures: (1) calcium hydroxide + amalgam + IRM surface seal; (2) OptiBond Solo, Prodigy with IRM surface seal; or (3) OptiBond Solo, Prodigy without IRM surface seal. The presence, absence, and quality of a hard tissue barrier were evaluated histologically. RESULTS: The calcium hydroxide groups were statistically superior to all other groups. The IRM surface seal resulted in significantly better healing. Although there was no statistically significant difference between direct pulp capping and partial pulpotomy with the numbers in this study, power statistics indicated that in clinical practice a partial pulpotomy would be preferable. CLINICAL SIGNIFICANCE The results of this study suggest that a partial pulpotomy, calcium hydroxide medicament, and a bacteria-tight coronal restoration represent a viable technique for capping the inflamed pulp.

Animals↗
PubMed2002

Ceramics.

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Ceramics↗
PubMed2002

Microleakage of Class V composites using different placement and curing techniques: an in vitro study.

PURPOSE: To evaluate microleakage at enamel and dentin margins of two composite resins, using bulk and incremental placement techniques, "rebonding", and facial and lingual curing methods. MATERIALS AND METHODS: One hundred standardized Class V cavity preparations were made on the facial surface of extracted human premolars and were randomly assigned to 10 groups. Single Bond was used as the dentin/enamel adhesive. A heavily filled composite resin, Z250, and a microfill, Silux Plus, were inserted and polymerized using five different techniques: (1) incremental placement and facial curing; (2) incremental placement, facial curing and rebonding; (3) bulk placement and facial curing; (4) bulk placement, facial curing and rebonding; (5) incremental placement and lingual and facial curing. After the restorations were finished and polished, the margins of those in the rebonded groups were etched, rinsed, and dried. The adhesive resin, Single Bond, was applied at the composite resin-tooth interface and light-cured. All the specimens were thermocycled, stained with 1% methylene blue, sectioned, and evaluated for leakage (0-4 scale) by two examiners. RESULTS: Almost no leakage occurred at enamel margins. At the cementum margins, differences in microleakage related to restorative material or technique were not statistically significant. However, leakage at the cementum margins was significantly greater than at the enamel margins for both composite resin materials.

Bicuspid↗
PubMedDate not supplied

Evaluation of pumice, fissure enameloplasty and air abrasion on sealant microleakage.

PURPOSE: The purpose of this in vitro study was to evaluate microleakage of pit and fissure sealants after using three different pit and fissure preparation techniques: (1) traditional pumice prophylaxis and acid etching, (2) fissure enameloplasty and acid etching and (3) air abrasion and acid etching. METHODS: Sixty extracted third molars with no clinical evidence of caries were randomly divided into 3 groups of 20 each. Teeth were prepared using 1 of 3 occlusal surface treatments prior to placement of Delton opaque light-cured sealant. The teeth were thermocycled between 5 +/- 2 degrees C and 55 +/- 2 degrees C for 500 cycles with a dwell time of 30 seconds and then stored in 0.9% normal saline. All teeth were sealed apically and coated within 1.5 mm of the sealant margin with two layers of nail varnish. The teeth were immersed in a 1% solution of methylene blue for 24 hours to allow dye penetration into possible gaps between enamel and sealant. Three buccolingual cuts parallel to the long axis of the tooth were made yielding 4 sections and 6 surfaces per tooth for analysis. The surfaces were scored 0 to 3 for extent of microleakage using a binocular microscope at 25X magnification. RESULTS: Kruskal-Wallis and t tests revealed no significant difference in microleakage between the 3 fissure preparation methods prior to sealant placement. CONCLUSIONS: Neither air abrasion nor enameloplasty followed by acid etching produced significantly less microleakage than the traditional pumice prophylaxis with acid etching technique.

Acid Etching, Dental↗
PubMedDate not supplied

Curing light intensity effects on wear resistance of two resin composites.

This in vitro study evaluated the wear resistance of resin composite polymerized using four different light-curing systems. For this, a well-defined cylindrical cavity preparation (4.0 mm in diameter x 3.0 mm in depth) was made in a ceramic block (n=4 per material/light condition). Uncured material, either a universal hybrid composite (Herculite XRV) or a flowable hybrid composite (Revolution Formula 2), was packed and light-cured from the top surface only with one of the four light-curing units: 1) a conventional quartz-tungsten-halogen light, 2) a soft-start light, 3) an argon-ion laser or 4) a plasma-arc curing light. After storing the specimens in deionized water at 37 degrees C for 24 hours, the excess cured material was ground through successive grits up to a final 1200-grit SiC abrasive. The specimens were placed in deionized water at 37 degrees C for an additional 24 hours. Wear simulation was performed using a four-station Leinfelder-type three-body wear device. A slurry of water and unplasticized polymethylmethacrylate beads, simulating an artificial food bolus, was placed on the surface of each resin-composite-restored ceramic block. The entire cycling procedure was carried out 400,000 times. Impressions of each resin composite surface were taken with polyvinylsiloxane and epoxy replicas were made. Wear analyses were conducted by generating tracings across the worn surface of epoxy replicas using profilometer scans. For the universal hybrid composite and the flowable hybrid composite, the lowest wear occurred in specimens that were cured using the conventional quartz-tungsten-halogen light, and the highest wear was detected on those specimens made using the argon-ion laser. For both resin composites, the mean wear for specimens cured using the argon-ion laser was significantly higher than that of the specimens cured with the three other lights, which were statistically similar.

Analysis of Variance↗
PubMedDate not supplied

Dentin/enamel adhesives: review of the literature.

This paper describes the development of dentin bonding systems, and describes the current strategies for bonding composite resin materials to dentin. Two main strategies are available--total-etch or self-etch--and each has unique advantages and disadvantages. For each category, simplified systems that reduce the number of application steps are available. Currently, the market is moving towards self-etching materials, largely because these are associated with less post-operative tooth sensitivity. However, the clinical performance of most of these materials is not yet proven.

Acid Etching, Dental↗