Biomedical subjects

David N Bardwell

Publications and source records attributed to David N Bardwell.

13 recordsLinked to original sources

PubMed2006

Integration of composite and ceramic restorations in tetracycline-bleached teeth: a case report.

UNLABELLED: The success of an esthetic rehabilitation depends on the understanding of the patient's need and expectation. The management of patients with moderate to severe tetracycline-stained teeth is very challenging. Tooth whitening may be a valid alternative to more aggressive treatments; however, patients should be aware of the limitations of tooth whitening therapy. Clinicians may select differing treatment plans; tooth whitening can improve intrinsic discoloration in a way so that no further treatment is required. Once tooth whitening is completed, direct or indirect restorative procedures may be afforded to match the existing restoration with the bleached tooth structure. This article describes a conservative clinical approach to rehabilitate the smile of a patient with moderate to severe tetracycline-stained teeth using a combination of tooth whitening and direct composite and indirect porcelain restorations in the maxillary anterior segment. CLINICAL SIGNIFICANCE: The combination of tooth whitening and adhesive restorations allows clinicians a significantly more conservative approach to intrinsically stained teeth; tooth preparation for porcelain veneers and porcelain-fused-to-metal and full-ceramic crowns can be restricted to conditions in which persistent tooth discoloration or significant loss of both dentin and enamel exists.

Adult↗

PubMed2006

Clinical evaluation of direct cuspal coverage with posterior composite resin restorations.

BACKGROUND: Composite resins have esthetic properties; they join the ability to preserve and reinforce sound tooth structure. Conservation is becoming popular for both small to medium defects and more compromised teeth. PURPOSE: This study aimed to evaluate the clinical performance of Class II cuspal coverage direct composite restorations. MATERIALS AND METHODS: Twenty patients, 18 years or older, were included in this clinical trial restoring 25 vital molar teeth with one or two missing cusps. Criteria for inclusion are two or three surface restorations, replacement of composite and amalgam fillings (secondary decay, fracture of either filling material or tooth structure, aesthetic considerations), or virgin teeth with decay undermining a cusp. Teeth with residual cavity walls less than 1 mm or with complete loss of the clinical crown were excluded. Teeth were restored using a combination of Ultra-Etch 35% phosphoric acid, PQ1 adhesive system, and Vit-l-escence microhybrid composite resin (Ultradent Products, Inc., South Jordan, UT, USA). The enamel peripheral skeleton of the restoration was built up first, followed by dentin and enamel occlusal surface stratification. Wedge-shaped increments of composite resin were placed and cured using the variable intensity polimerizer (VIP) light (Bisco Inc., Schaumburg, IL, USA) through a combination of a pulse and progressive curing technique. RESULTS: All 25 restorations were evaluated at 6-month intervals during the 30-month period using a modified US Public Health Service (USPHS) criteria by two independent evaluators precalibrated at 85% reliability. No failures were reported and alpha scores were recorded for all parameters. Statistical analysis was performed using a Chi-square test (chi(2)) and the Fisher's exact test. Sixteen of the 25 samples (64%) exhibited preoperative sensitivity to air (chi(2)=10.6; p=0.001). A significant difference in tooth sensitivity was reported after completion of the restorations. No teeth exhibited sensitivity both at the 2-week recall and the 30-month follow-up (chi(2)=23.5; p < 0.0001). CONCLUSION: Microhybrid composite resin demonstrated excellent clinical performance in direct cuspal coverage at completion of a 30-month evaluation. CLINICAL SIGNIFICANCE In selected clinical situations, cuspal coverage direct posterior composite restorations may represent a valid alternative to conventional indirect restorations.

Acrylic Resins↗

PubMed2005

Two-year clinical evaluation of nonvital tooth whitening and resin composite restorations.

BACKGROUND: Adhesive systems, resin composites, and light curing systems underwent continuous improvement in the past decade. The number of patients asking for ultraconservative treatments is increasing; clinicians are starting to reevaluate the dogma of traditional restorative dentistry and look for alternative methods to build up severely destroyed teeth. PURPOSE: The purpose of this study was to evaluate the efficacy of nonvital tooth whitening and the clinical performance of direct composite restorations used to reconstruct extensive restorations on endodontically bleached teeth. MATERIALS AND METHODS: Twenty-one patients 18 years or older were included in this clinical trial, and 26 endodontically treated and bleached maxillary and mandibular teeth were restored using a microhybrid resin composite. Patients with severe internal (tetracycline stains) and external discoloration (fluorosis), smokers, and pregnant and nursing women were excluded from the study. Only patients with A3 or darker shades were included. Teeth having endodontic access opening only to be restored were excluded; conversely, teeth having a combination of endodontic access and Class III/IV cavities were included in the study. A Vita shade guide (Vita Zahnfabrik, Bad Säckingen, Germany) arranged by value order was used to record the shade for each patient. Temporary or existing restorations were removed, along with a 1 mm gutta-percha below the cementoenamel junction (CEJ), and a resin-modified glass ionomer barrier was placed at the CEJ. Bleaching treatment was performed using a combination of in-office (OpalescenceXtra, Ultradent Products, South Jordan, UT, USA) and at-home (Opalescence 10% PF, Ultradent Products) applications. Two weeks after completion of the bleaching, the teeth were restored using a combination of PQ1 adhesive system and Vit-l-escence microhybrid resin composite (Ultradent Products). Wedge-shaped increments were placed and cured using the VIP Light (Bisco, Inc Schaumburg, IL, USA) through a combination of pulse and progressive curing techniques. RESULTS: All but one restoration were evaluated by two independent evaluators every 6 months during a 2-year period using modified US Public Health Service criteria. No restoration failed and "alpha" scores were recorded for all parameters but color stability, which was scored "bravo." Analysis of variance showed a significant shade change between baseline (mean=14.4+/-1.9) versus 2 weeks (mean=1.6+/-0.7) and 2 years (mean=2.8+/-1.7) (p<.0001). Although a significant shade change was observed between 2 weeks and the 2-year follow-up (p=.008), no significant difference was reported between the baseline and 2 weeks (12.9+/-2) versus baseline and 2 years (11.9+/-2.3). CONCLUSIONS: Significant tooth lightening was reported after the completion of whitening therapy on devitalized teeth; shade rebound was reported in less than 50% of the treated teeth and was limited to a maximum of four shades. A microhybrid resin composite demonstrated excellent clinical performance in the restoration of all endodontically treated and bleached teeth after a 2-year evaluation period. CLINICAL SIGNIFICANCE: Nonvital tooth whitening is responsible for a significant change in color of endodontically stained teeth. Successful nonvital tooth-whitening therapy allows for conservative tooth preparation, preserving and reinforcing sound tooth structure. The proper use of modern adhesive systems along with resin composite restorations precludes the use of more extensive restorative treatment, delaying expensive crown and bridge procedures.

Carbamide Peroxide↗

PubMed2005

Layering and curing techniques for class III restorations: a two-year case report.

The direct resin buildup of a Class III restoration based on contemporary layering and curing techniques allows clinicians to provide conservative treatment and a virtually imperceptible blend with adjacent tooth structures. This presentation describes a new approach to the Class III buildup. The importance of restoring enamel and dentin as two different substrates is also stressed. In this context, the selection of a microhybrid composite resin system able to reproduce the optical and mechanical properties of the natural dentition can help to achieve these goals.

Acrylic Resins↗

PubMed2005

Reconstruction of devital teeth using direct fiber-reinforced composite resins: a case report.

Nonrestored devitalized teeth are structurally compromised and represent one of the greatest challenges for the clinician. Restoration of endodontically treated teeth has been associated with the use of posts. Various post materials and designs have been introduced over the years; however, motivated by the desire to conserve the remaining sound tooth structure and thanks to properties of modern adhesive systems, clinicians have re-evaluated the dogma of traditional restorative dentistry and seek alternative methods to build up devitalized teeth. The use of direct Ultra High Molecular Weight Polyethylene (UHMWPE) fiber-reinforced post systems is becoming popular among clinicians because enlargement of the root canal space is not required and the risk of root perforation eliminated. This article presents an experimental clinical technique to reconstruct severely damaged endodontically treated posterior teeth using direct fiber reinforced post systems. Particular attention is paid to the incremental and curing techniques adopted to build up the restoration. The problems that clinicians can encounter in bonding to teeth that have undergone endodontic treatment are also analyzed. Questions that have yet to be answered by scientific research are presented.

Composite Resins↗

PubMed2004

Clinical evaluation of a combined in-office and take-home bleaching system.

BACKGROUND: Tooth whitening is one of the fastest growing areas in cosmetic and restorative dentistry. An increasing number of patients are demanding faster ways to bleach their teeth. Therefore, clinicians are being pushed to seek quicker and easier means to bleach their patients' teeth, while maintaining safety in bleaching procedures. METHODS: The authors included in the clinical trial 10 subjects 18 years of age or older, each of whom had six caries-free maxillary anterior teeth without restorations on the labial surfaces and no tooth sensitivity. For each subject, one-half of the maxillary arch received a 35 percent hydrogen peroxide (Group 1) gel application for 30 minutes, and the other one-half of the maxillary arch received a 38 percent hydrogen peroxide (Group 2) gel application for 30 minutes. The in-office bleaching treatment was maintained and reinforced using a 10 percent carbamide peroxide at-home bleaching agent for 60 minutes. Subjects repeated both the in-office and take-home bleaching treatments for three consecutive days. RESULTS: The shade change was 8.5 for Group 1 and 9 for Group 2. There was no statistically significant difference between the two groups (P = .3434). An average shade rebound of two shades was recorded at seven days for both treatment systems. No sensitivity was reported during or after the bleaching treatment. CONCLUSIONS: When combined with 10 percent carbamide peroxide at-home applications, use of the Group 1 and Group 2 bleaching materials resulted in significant tooth lightening. CLINICAL IMPLICATIONS: By using the clinical technique presented, clinicians can reduce the time required to complete tooth-whitening treatment. Using the correct tray design and improved chemical formulations of tooth whiteners may reduce gingival and tooth sensitivity, thus increasing safety.

Adolescent↗

PubMed2004

Microleakage of a microhybrid composite resin using three different adhesive placement techniques.

PURPOSE: To evaluate the efficacy of two adhesive systems in reducing microleakage when applied with three different adhesive placement techniques. MATERIALS AND METHODS: Sixty freshly extracted caries-free human premolars and molars were used. MO/DO Class II standardized preparations were performed with the gingival margin placed 1 mm above the CEJ. Teeth were randomly divided into 2 groups (group I: Prime& Bond NT, Dentsply/Caulk; group II: Single Bond, 3M Espe). Each group was divided into 3 subgroups: (A) application of 2 coats and one cure: IA-IIA; (B) 2 coats and 2 cures of each adhesive system: IB-IIB; and (C) one coat of each adhesive along with the manufacturers' B1 flowable resin (0.5-mm thick layer) cured together at once: IC-IIC. Each coat was cured for 20 s at 800 mW/cm2 using a quartz-tungsten halogen light (Elipar Trilight, 3M ESPE). Teeth were then restored using 2-mm increments of an A2 microhybrid composite (Esthet-X, Dentsply/Caulk). All teeth were stored in distilled water at 37 degrees C for 24 h, thermocycled (500x, 5 degrees to 55 degrees C, 30 s dwell) and then placed in a 0.5% methylene blue dye solution for 24 h at 37 degrees C. Samples were sectioned longitudinally and evaluated for microleakage at the gingival margin under a stereomicroscope at 20x magnification. Dye penetration was scored using an ordinal scoring system, where 0: no penetration; 1: enamel penetration; 2: gingival dentin penetration; 3: axial dentin penetration. Kruskal-Wallis and Mann-Whitney tests were used. RESULTS: A Mann-Whitney U-Test revealed no statistically significant difference between subgroups. Although not statistically significant, P&B NT (two coats and one cure) revealed the lowest microleakage scores. CONCLUSION: In the experimental model adopted for this study, microleakage was not affected either by the adhesive or its placement technique.

Bisphenol A-Glycidyl Methacrylate↗

PubMed2003

Reconstruction of severely damaged endodontically treated and bleached teeth using a microhybrid composite resin: two-year case report.

Clinical indications for direct composite restorations have expanded in the last decade, primarily due to improved physical, aesthetic, and handling properties. As a consequence, their increased predictability has encouraged clinicians to progressively abandon amalgam. This article presents a clinical protocol to reconstruct severely damaged endodontically treated and bleached anterior teeth with particular emphasis on placement and curing techniques. Common complications encountered during the bonding of teeth that have undergone endodontic and bleaching treatments are also analyzed.

Adult↗

PubMed2003

Effect of different polymerization methods on composite microleakage.

PURPOSE: To evaluate the microleakage of a condensable resin composite using a microhybrid flowable composite as a liner, cured with four different methods of polymerization. METHODS: 40 freshly extracted caries-free human premolars and molars were used. MO/DO Class II standardized preparations were performed with the gingival margin placed 1 mm above the CEJ. Teeth were randomly divided into four groups. Group 1 (control group): conventional mode (Elipar Highlight), Group 2: step mode (Elipar Highlight), Group 3: ramp mode (Elipar Trilight) and Group 4: pulse mode (VIP). Preparations were etched with 32% phosphoric acid (Uni-Etch) and an adhesive system (One-Step) was used according to the manufacturer's instructions. Teeth were then restored using a 1 mm layer of flowable composite (A2 AEliteflo LV) on the gingival and pulpal floor and condensable composite (Pyramid A2 Dentin and A1 Enamel) in 2 mm increments. Teeth were thermocycled x500 between 5 degrees C and 55 degrees C with a dwell of 30 seconds and then placed in a 0.5% methylene blue dye solution for 24 hours at 37 degrees C. Samples were sectioned longitudinally and evaluated for microleakage at the gingival margin under a stereomicroscope at x30 magnification. Dye penetration was scored using an ordinal scoring system as 0: no penetration; 1: enamel penetration; 2: dentin penetration. RESULTS: A Mann-Whitney U Test revealed a statistically significant difference between Group 1 with Groups 2, 3 and 4 (P < 0.001). Group 1 yielded the most microleakage. No statistically significant difference was noted between Groups 2, 3 and 4.

Acid Etching, Dental↗

PubMed2003

Microleakage of resin-based liner materials and condensable composites using filled and unfilled adhesives.

PURPOSE: To evaluate the efficacy of differing resin based liner materials in reducing microleakage. METHODS: 80 freshly extracted caries-free human premolars and molars were used. MO/DO Class II standardized preparations were performed with the gingival margin placed 1 mm above the CEJ. Teeth were randomly divided into two groups; each one was divided into four subgroups (A-B-C-D for Group 1 and E-F-G-H for Group 2). Each prepared tooth was etched with 32% H3PO4 (Uni Etch); in Group 1, one coat of One Step and in Group 2, two coats and two cures of Prime & Bond NT adhesives were applied. In each group 1 mm layer of three different liners was used: A2 Heliomolar RO for A and E; A2 Heliomolar Flow for B and F; A2 Bisfil 2B for C and G. No liner was used for D and H subgroups. Teeth were then restored using 2 mm increments of Pyramid A2 Dentin and A1 Enamel and cured with a VIP curing light. Teeth were thermocycled x500 between 5 degrees C and 55 degrees C with a dwell of 30 seconds and then placed in a 0.5% methylene blue dye solution for 24 hours at 37 degrees C. Samples were sectioned longitudinally and evaluated for microleakage at the gingival margin under a stereomicroscope at x20 magnification. Dye penetration was scored using an Ordinal Scoring System where 0= no penetration; 1= enamel penetration; and 2= dentin penetration. RESULTS: A Chi Square Test revealed a statistically significant difference between Group 1 and Groups 2 (P < 0.001). Group 1 yielded the most microleakage. No statistically significant difference was noted between the subgroups of each group; a statistically significant difference of B and D vs. E and H (P < 0.01 > 0.001) and B vs. G and D (P < 0.05 > 0.01) was also noted. The dentin bonding agent in Group 2 contributed to a reduction of microleakage when compared to Group 1.

Acid Etching, Dental↗

PubMed2002

An alternative method to reduce polymerization shrinkage in direct posterior composite restorations.

BACKGROUND: Polymerization shrinkage is one of dental clinicians' main concerns when placing direct, posterior, resin-based composite restorations. Evolving improvements associated with resin-based composite materials, dental adhesives, filling techniques and light curing have improved their predictability, but shrinkage problems remain. METHODS: The authors propose restoring enamel and dentin as two different substrates and describe new techniques for placing direct, posterior, resin-based composite restorations. These techniques use flowable and microhybrid resin-based composites that are polymerized with a progressive curing technique to restore dentin, as well as a microhybrid composite polymerized with a pulse-curing technique to restore enamel. Combined with an oblique, successive cusp buildup method, these techniques can minimize polymerization shrinkage greatly. CONCLUSIONS: Selection and appropriate use of materials, better placement techniques and control polymerization shrinkage may result in more predictable and esthetic Class II resin-based composite restorations. CLINICAL IMPLICATIONS: By using the techniques discussed by the authors, clinicians can reduce enamel microcracks and substantially improve the adaptation of resin-based composite to deep dentin. As a consequence, marginal discoloration, recurrent caries and postoperative sensitivity can be reduced, and longevity of these restorations potentially can be improved.

Acid Etching, Dental↗

PubMedDate not supplied

Direct cuspal-coverage posterior resin composite restorations: A case report.

The clinical success of direct composite restorations is the result of the correct use and performance of adhesive systems, resin composites and light curing systems. Total-etch adhesive systems and microhybrid resin composites have seen continuous improvement; various clinical techniques have been introduced to address polymerization shrinkage. Manufacturers have introduced sophisticated light-curing devices with the hope of improving performance. Direct resin bonded composites (RBCs) are becoming the first choice in many clinical situations. This article presents an experimental clinical technique that outlines the reconstruction of severely damaged posterior teeth missing multiple cusps; particular attention to incremental and curing techniques is adopted to complete each restoration.

Acid Etching, Dental↗

PubMedDate not supplied

In vitro evaluation of giomers microleakage after exposure to 33% hydrogen peroxide: self-etch vs total-etch adhesives.

This study evaluated the microleakage of a giomer resin bonded with total-etch and self-etch adhesive systems after exposure to hydrogen peroxide. Thirty freshly extracted, caries-free human premolars and molars were used. The teeth were randomly divided into two groups: Group I was exposed to 33% hydrogen peroxide (Niveous-Shofu) for 30 minutes daily for five consecutive days; Group II received no treatment (control). A week later, Class V standardized preparations were performed on the facial and lingual surfaces, with the gingival margin placed 1 mm below the CEJ. Each group was then divided into two subgroups: in Groups IA and IIA, a self-etching adhesive system (FL Bond-Shofu) was applied, and in Groups IB and IIB, a total-etch adhesive system (Prime Bond NT-Dentsply/Caulk) was applied according to manufacturers' instructions. The teeth were restored using 2-mm increments of Beautifil A2 resin-based giomer material (Shofu). Each layer was cured using a Spectrum 800 curing light (Dentsply/Caulk) for 20 seconds at 600mW/cm2. The teeth were thermocycled 500x between 5 degrees C and 55 degrees C with a dwell of 30 seconds; they were then placed in a 0.5% methylene blue dye solution for 24 hours at 37 degrees C. Samples were sectioned longitudinally and evaluated for microleakage at the occlusal and gingival margin under a stereomicroscope at 20x magnification. Dye penetration was scored using the following scoring system 0 = no penetration; 1 = partial dye penetration along the occlusal or gingival wall; 2 = partial dye penetration along the occlusal or gingival wall but did not include the axial wall; 3 = dye penetration to and along the axial wall. A Mann-Whitney test revealed a statistically significant difference between subgroups at the occlusal level (p < 0.0001). Group IA yielded the most microleakage. No statistically significant difference was reported at the gingival level. Microleakage was affected by hydrogen peroxide exposure only at the enamel cavosurface margin when a self-etching primer adhesive system was used.

Acid Etching, Dental↗