Preston Beck

• MS Biomedical Engineering
• Research Associate at University of Alabama at Birmingham

Objectives: To measure microleakage around class V composite restorations after piezoelectric ultrasonic scaling and sonic toothbrushing. Methods: 3 mm × 2 mm × 1.5 mm boxes were prepared on buccal and lingual surfaces of extracted molars centered on the cementum-enamel junction. Half the preparations were beveled (0.5 mm). Preparations were res...

Objective The study aims to compare in vitro stain resistance, color stability, gloss, and gloss retention of a nano-filled resin-modified glass ionomers (RMGIs) to a traditional RMGI and resin-based composites (RBCs).Materials and Methods Specimens (N = 20) were fabricated from a nano-filled RBC (Filtek Supreme Plus, 3M ESPE, St. Paul, MN, USA), a...

Statement of problem: Lithium disilicate is a translucent, glass-containing material used for ceramic restorations. Clinicians frequently use alumina abrading or hydrofluoric acid etching to create micromechanical retention in the intaglio surface before bonding a lithium disilicate restoration to the tooth. Few studies have investigated how the e...

Objectives: Lithium disilicate is a glass-containing ceramic for all-ceramic restorations. During fabrication or before bonding to the preparation, alumina oxide abrasion or HF acid-etching may be used to create micromechanical retention. Few studies have investigated how HF etching or abrasion affects the flexural strength of lithium disilicate ce...

Statement of problem: Light cured acidic adhesives used with dual cured resin cements adversely affect polymerization of composite resins producing low bond strengths unless the adhesive is mixed with a dual cure activator. Adhesives with higher pH may be more compatible with dual cured resin cement. Objectives: To measure and compare the shear bon...

Objective: This study compared the marginal breakdown of two restorative composite materials placed in human extracted teeth using an accelerated testing protocol. Methods: 16 extracted intact (no caries or cracks) human mandibular molars were randomly divided into 2 groups and placed into cylinders filled with acrylic resin. After polymerization...

Objective: This study measured bond strengths of 4 adhesives to metal and ceramic with and without thermocycling. Method: 194 metal and 160 ceramic coupons were polished (300- and 600-grit SiC/15 sec/90° rotation), metal only abraded (50 µm Al2O3/15 sec), and sonicated (acetone, 10 min). Adhesives were applied following manufacturers’ instruction...

Objective: To measure the dentin shear bond strength (SBS) of four adhesives before and after an application of a hydroxyapatite (Tetracalcium phosphate and dicalcium phosphate anhydrate, Teethmate Desensitizer, Kuraray) forming desensitizer. Method: Freshly extracted intact human molars (n=80) were wet-ground with a series of abrasive discs (8...

Objective: Contact angle, the internal angle a droplet of liquid forms in contact with impression material to measure a material’s wettability. This study compared contact angles made by distilled water on 7 unset impression materials at 5 time periods from the start of mix. Method: Keyence VHX-600 microscope (with 40x zoom video recorder) record...

Durable adhesive bonds are required for restoration retention. New adhesives are being developed which may improve long-term restoration retention. Objective: The purpose of the study was to compare the shear bond strength of three adhesives used in the self-etch mode to enamel and dentin before and after thermocycling. Method: Freshly extracte...

Objective: Measure 24hr and thermocycled shear bond strength (SBS) of universal bonding agents tested on etched enamel, uncut enamel and dentin surfaces. The line of universal bonding agents produced by several companies are intended to bond to enamel, dentin, glass ceramic, zirconia, noble and non-precious alloys, and composites without using a pr...

Intravascular nitinol stents are used in the treatment of atherosclerosis and intracranial aneurysms. Despite the unique physical properties of shape memory and superelasticity, the chemical composition of NiTi has raised concerns due to the presence of nickel ions within the alloy which can have adverse effects on human health. Currently, stents a...

A program operated since 1970 is now transitioning to an evidenced-based education (EBE) format and is utilizing examples of medical device retrieval and analysis (DRA) to introduce basic and applied concepts on the compatibility and longevity of device and host interactions. This paper provides an approach to EBE utilizing principles from the phys...

Lithium disilicate is an etchable ceramic used for bonded restorations. Objectives: To measure 24hr and thermocycled shear bond strength (SBS) of Scotchbond Universal to e.max CAD after silane and hydrofluoric acid surface treatments and salivary contamination and cleaning. Methods: e.max CAD blocks were sectioned, polished (180, 320-grit SiC-p...

Cements are used to retain indirect restorations to the prepared teeth. These cements may be subject to wear in the oral environment. Objective: To measure and compare in vitro wear resistance of five cements against human enamel cusps. Methods: Sixteen flat rectangular specimens of each cement were prepared using an elastomeric mold which prod...

Objectives: To measure and compare retention of four fiber post systems to prepared post space and core materials. Methods: Roots of freshly extracted first mandibular premolars without caries, cracks or defects were selected. Radiographs were made in the B-L and M-D direction to exclude teeth with abnormal canal shapes. - Only teeth with a root...

Objective: Most current generation dental composites incorporate nano-scale filler particles. The aim of this study is to examine the effects of nano-filler concentration on the mechanisms of wear of an experimental dental composite. Method: Nano-filled composites were fabricated with a BisGMA polymer matrix and 40nm SiO2 filler particles at thre...

Objective : To evaluate the wear of enamel opposing veneering ceramics, gold, emax and zirconia. Methods : The study (n=8) includes Lava (zirconia), lithium di-silicate (e.max CAD), gold alloy (Harmony-C&B-55), 3 groups of feldspathetic veneering ceramics (TriLuxe, d.SIGN and VM9) and an enamel (control). Molar cusps were shaped into a standardiz...

Objective: To measure and compare the wear of human enamel against adjusted; adjusted and polished; adjusted, polished and glazed zirconia and lithium di-silicate and the wear of each ceramic. Methods: The study (n=8) included three groups of lithium di-silicate (e.max), three groups of zirconia (Lava), a veneering porcelain (Ceramco 3), and enam...

Wear resistance is a clinical concern for composites (flowable and packable) that are being developed for bulk placement and curing in posterior restorations. Objective: To determine and compare in vitro three-body wear of 8 commercially available bulk placed composites. Methods: Eight flat disc specimens (n=8) of each composite material (d=8mm/h=2...

Polymerization shrinkage is a primary concern when placing composite restorations. Strain produced during polymerization shrinkage may initiate failure at the composite-tooth interface producing marginal gaps, post-operative sensitivity, micro-leakage and caries. Objectives: To measure and compare polymerization shrinkage strain of commercially a...

Full veneer zirconia crowns are increasing in use due to their increased strength, increasing metal costs and esthetic appearance. These crowns do not require bonding and can be cemented with glass ionomer cements. Objective: To measure and compare retention rates of zirconia crowns cemented with three commercially available cements. Method: Ex...

Objectives: To compare the shear bond strength of three resin cement and two commercially available resin cements onto 4 substrates (IPS e.max-CAD, Co-Cr alloy, ground enamel and dentin). Methods: Ceramic blocks (IPS e.max-CAD/Ivoclar Vivadent) were sectioned (4mm), polished (320-grit SiC) and finished (0.5 Al2O3 slurry). Human molars were wet-gr...

Statement of problem: The wear of tooth structure opposing anatomically contoured zirconia crowns requires further investigation. Purpose: The purpose of this in vitro study was to measure the roughness and wear of polished, glazed, and polished then reglazed zirconia against human enamel antagonists and compare the measurements to those of vene...

Objective: To evaluate bone response around Co-alloy custom implants (HA plasma coating) and HA (hydroxyapatite) particulates from 3 post mortem human donors. Methods: Three individual mandibular custom osseous integrated implant devices at 10-11 years of function were processed (six transverse locations) to obtain non-decalcified ground sections...

The purpose of this study was to compare four medium particles currently used for in vitro composite wear testing (glass and PMMA beads and millet and poppy seeds). Particles were prepared as described in previous wear studies. Hardness of medium particles was measured with a nano-indentor, particle size was measured with a particle size analyzer,...

Objectives: To measure and compare the 24-hour microtensile bond strength of four self etching adhesives (Table) to dentin. Methods: Freshly extracted human molars were wet-ground with a series of silica carbide paper ending with 320 grit to obtain flat intermediate level dentin surfaces and a uniform smear layer using a rotational polishing device...

Objective: Measure and compare-In vitro color change produced by coloring agent [(Lustre Paste IQ (LP) (GC-America)] on ceramic [Initial(GC-America), emax CAD(Ivoclar-vivadent), Zirconia (Cercon Base30(Dentsply)] specimens, durability of color after load cycles and flexural strength measurement with and without application of LP. Method: Colo...

Objectives: To measure retention of zirconia crowns cemented with an experimental (3M-ESPE) and 2 commercially available (Multilink Automix/Ivoclar, Panavia F2.0/Kuraray) cements under different surface preparation conditions (Table). Methods: 50 extracted teeth (n=10) were embedded in brass holders and placed into a lathe to produce a uniform cr...

Objectives: To measure and compare compressive strength, yield strength and wear resistance of a giomer, BEAUTIFIL Flow Plus, to flowable composite resins, PREMISE hybrid and SureFil SDR flowable. Methods: Compressive and yield strength: Specimens (n=10) were prepared using a Teflon split mold (d=4mm/h=8mm) following manufacturers' instructions f...

Objectives: To measure retention of CAD-CAM e.max (Ivoclar Vivadent) and Lava (3M-ESPE) crowns using three resin luting agents with and without surface priming. Methods: Extracted molars (n=10) were embedded in PVC cylinders with acrylic resin and placed into a lathe to produce a uniform crown preparation (20-taper). Following the orientation gro...

Wear of posterior restorative materials is a significant clinical problem over the life of the restoration. Objectives: To measure and compare the in vitro wear of three glass ionomer restorative materials (Riva Self-Cure LV/SDI, ChemFil Rock/Dentsply, Fuji IX/GC) and (control) a resin composite (Z100/3M ESPE) restorative material. Methods: Eight...

Objectives: 1) Measure 24hr and thermocycled shear bond strength/(SBS) of Scotchbond Universal/3M ESPE to ParadigmC, LAVA core, IPS e.max CAD, gold and base metal alloy 2) Measure 24hr and 10month SBS of an experimental adhesive to unetched and etched ground human dentin and enamel. Methods: ParadigmC, e.maxCAD, LAVA blocks and non-noble metal al...

Denture teeth need to have sufficient wear-resistance in the partially edentulous patient with opposing natural teeth. Objectives: This study measures and compares the in vitro wear of denture teeth against human enamel. Methods: Mandibular molar denture teeth from 3 manufactures (see table) and extracted human teeth (control) were ground with...

Objective: To measure the wear of 6 restorative materials. Methods: Eight flat disc specimens (n=8) of each composite material (d=10mm/h=4mm) were prepared using a flexible mold following manufacturers' instructions. Each composite was placed into the mold in 2mm increments and light-cured (Elipar S10/3M ESPE/1020mW/cm2). After curing the specime...

Objective: To develop a non invasive, reproducible technique to measure non-carious cervical lesion (NCCL) progression and correlate it with occlusal biting pressure forces. Method: Sixty teeth from twenty-six patients with NCCLs were used in the study. Elastomeric impressions and digital images were made of each subject at baseline, one year, an...

Objectives: To measure the compressive strength of three pulp capping materials at 3 times and record the marginal seal of Biodentine and N'Durance resin-based composite at the tooth-restoration interface. Methods: Compressive Strength: Samples (n=10) of Biodentine, MTA, and Dycal/LD Caulk were prepared using Teflon cylinder molds (d=4/h=8mm), stor...

Aging dental zirconia roughens its surface due to transformation from the tetragonal to the monoclinic state. Objectives: The effects of age-related roughening of zirconia on the wear of tooth enamel was measured. Methods: Specimens (n=8) were prepared by the manufacturer (3M ESPE) and divided into three groups: polished zirconia (LAVA), aged zirco...

Objectives: To measure and compare fracture strength of monolithic and bilayered LAVA and e.max crowns after load cycling. Methods: To compare fracture strengths of bilayered and monolithic LAVA zirconia/3M ESPE and e.max lithium disilicate/Ivoclar Vivadent crowns prepared with varying manufacturing techniques and thicknesses (table). A full crow...

Objective: To evaluate the effect of polished, glazed, aged and adjusted zirconia on opposing enamel. Methods: The study (n=8) included 5 groups of zirconia ceramic (Table), a veneering porcelain (Ceramco 3) and enamel (control). The cusps of molars were standardized with a tapered diamond (Brasseler/USA) to serve as the opposing enamel tooth...

Objective: To compare three alginate substitute materials to an alginate impression material for cast surface porosity (outgassing), tear strength, and detail reproduction. Materials and methods: Detail reproduction tests were performed following American National Standards Institute/American Dental Association (ANSI/ADA) Specification No. 19. T...

Objective: Recent studies confirmed that resin-modified glass ionomers (RMGIs) set on the basis of two competing mechanisms, an acid-base reaction and a light-activated resin polymerization. This study evaluated the effect of the setting mechanism on bond strength by measuring the shear bond strength of three RMGIs to dentin with and without light...

Alginate substitute materials are polyvinylsiloxane (PVS) impression materials which may produce more than one cast and may be a replacement for traditional irreversible hydrocolloids. Objectives: To compare four alginate substitute materials to an alginate impression material for detail reproduction, cast surface porosity and tear strength. Me...

Clinical placement of an LED light curing guide tip may be at a distance from the composite being polymerized. Objectives: To measure and compare depth of cure (DOC) and hardness of composite resin with 3 distances between the light guide tip and the composite produced by 5 LED lights. Methods: Specimens were prepared using 5 different curing l...

A new caries infiltrating resin was introduced which treats demineralized subsurface white-spot lesions (WSL). To be effective, this infiltrating resin must be color stable. Objectives: To measure the color stability and stain resistance of a caries infiltrant resin compared to enamel, WSL and composite. Methods: 160 extracted caries free human mol...

An artificial mouth has been fabricated to allow continuous, rate-controlled flow of a lubricating fluid which serves as a saliva substitute during wear testing. Objective: The study compares volumetric wear of a composite material while varying viscosities and composition of the lubricant. Methods: Specimens (n=4) of Z100 were prepared in silicone...

OBJECTIVES: To compare cutting resistance of 7 core build-up materials with medium-grit diamond burs using an air rotor mounted in a precision custom designed substrate cutting device. METHODS: 56 specimens (n=8) were prepared using a split Teflon mold following manufacturers' instructions and light cured (1100mW/cm2, Elipar S10/3M). Specimens (l...

The University of Alabama wear testing device measures in-vitro wear of dental materials. However, the device does not incorporate a lateral sliding motion, temperature or pH cycling changes which may limit its ability to predict in-vivo wear. Recently an artificial mouth was developed which included weight-controlled loading, a 4mm horizontal slid...

Vitamin D deficiency plays an important role in the bone and dentin mineralization. Previous studies from our laboratory have demonstrated that in lower incisors of vitamin D deficient mice (VDR-/-), early enamel mineralization takes place when compared to its wild type counterpart (VDR +/+). Objective: to investigate the ultrastucture of enamel mi...

In vivo composite wear is a significant problem in large posterior restorations. To develop more wear resistant composite resin materials, wear machines that accurately predict in vivo wear are necessary. OBJECTIVE: To measure and compare the volumetric wear loss of in vitro specimens and in vivo restorations of a highly filled BisGMA nano-hybrid...

OObjective: To compare the polymerization shrinkage of 9 commercially available highly filled composite materials. Methods: Polymerization shrinkage was determined as percent shrinkage using ACUVOL, Volumetric Shrinkage Analyzer (BISCO Dental, Schaumburg, IL). Specimens were placed on the rotating pedestal of ACUVOL in equal amounts forming a spher...

Objective: To measure the wear of occlusal enamel and 4 restorative materials. Methods: Eight flat disc specimens (n=8) of each composite material (d=10mm/h=4mm) were prepared using a flexible mold following manufacturers' instructions. Each composite was placed in 2mm increments and light-cured. (Elipar S10/3M ESPE/1020mW/cm2). Specimens were st...

Chlorhexidine using a 2%, 1 minute application is recommended to stabilize the collagen layer and decrease bond strength degradation OBJECTIVE: To measure the shear bond strength to dentin at 24hours and 6months of a total- etch and self-etch adhesive after chlorhexidine was applied using 2 application times and 2 concentrations. METHODS: 240 c...

Objective: To measure and compare in vitro three body wear of 6 commercially available composites. Methods: Eight flat disc specimens of each composite (d=6mm/t=4mm) were prepared using a flexible mold following manufacturers' instructions, in two increments. Top layer was cured through a glass slide (Bluephase-IvoclarVivadent/1100mW/cm2). Specimen...

Flowable composite materials are less filled than traditional composites. Their composition allows ease of manipulation but makes these materials susceptible to increased polymerization shrinkage. Objective: To compare the polymerization shrinkage of one experimental and 7 commercially available flowable materials. Methods: Polymerization shrinkage...

The aim of the present study was to assess several parameters related to the clinical usage of 2 root canal preparation instruments: Vortex .06 rotary nickel-titanium instruments, and Safesiders reciprocating stainless steel instruments. Fifty extracted mandibular molars with mesial root canal curvatures between 20° and 50° were divided into 2 grou...

Objective: To examine mineral deposition pattern of alveolar bone, dentin, enamel and cementum in continually erupting incisors of the vitamin D receptor (VDR) knockout mouse model. Methods: Four groups of mice (3-6/group) were identified by genotyping: +/+ mice (wild type), -/- mice (VDR deficient), -/- offsprings derived from -/- parents receivin...

Objective: To evaluate the wear resistance of 5 commercially available resin composites and a high copper amalgam using an in vitro three-body wear tester. Methods: Eight flat disc specimens of each composite (d=6mm/t=4mm) were prepared using a flexible mold following manufacturers' instructions, in two increments. Top layer was cured through a gla...

Objectives: To measure and compare wear of occlusal enamel opposing three ceramic materials. Methods: Enamel styli (n=10) were prepared from caries-free maxillary premolar cusps. After wet polishing with a series of 400-, 600- & 1200-grit SiC paper, styli were mounted on the UAB Chewing. Flat rectangular ceramic blocks (n=10) (IPS e.max CAD/Ivoclar...

Objective: Recent studies confirmed that resin modified glass ionomers (RMGI) set based on two competing mechanisms, an acid-base reaction and a light-activated resin polymerization. This study evaluates the effect of setting mechanism on bond strength by measuring shear bond strength of three RMGIs to dentin with and without light activation. Meth...

Retention of posts in root canals relies on the strength of cements and techniques of application. As cements develop, different techniques are introduced and employed with the objective of enhancing post retention. Objective: To determine push out strength of fiber posts cemented using five techniques. Materials and Methods: Roots of 50 freshl...

The success of pit and fissure sealants depends on its retention and seal. Objective: To measure the shear bond strength and microleakage of an experimental pit and fissure sealant used with phosphoric acid etchant and in a self etch mode to uncut enamel and compare it to 4 pit and fissure sealants. Methods: 120 extracted non-carious human molars w...

Impression materials' hydrophilic properties are important to duplicate the details accurately for a better final restoration. Objective: To measure and compare the contact angle of 7 elastomeric impression materials at 6 time intervals. Methods: Five elastomeric regular-set and 2 fast-set impression materials were examined (n=5). Materials were di...

Innovative composite materials with monomers that reduce shrinkage are needed for clinically acceptable restorations. Objective: To determine and compare gloss, surface roughness (Ra), color stability and wear of 4 composite resins. Method: All materials were light cured (550mW/cm2) following manufacturers' instructions. Gloss and Ra: Discs (d=...

Flowable composite materials are less filled than traditional composites. By decreasing the proportion of filler, flowable composites adapt to small cavity preparations. They adapt better to the prepared tooth surface but increases the polymerization shrinkage and contact wear of flowables. While the wear resistance of flowable composites is a clin...

Unlike conventional wear that occurs on occlusal surfaces, toothbrush wear simulates abrasion on cervical surfaces. To have durable cervical restorative materials it is essential that they can withstand abrasive wear from brushing. OBJECTIVES: To evaluate and compare wear and toothbrush abrasion resistance of class-V restorative materials. METH...

Non-carious cervical lesions (NCCLs) have a non bacterial origin, frequently occur at the cemento-enamel junction and are frequently restored and unrelated to dental caries. OBJECTIVE: To develop a non-invasive, highly reproducible technique to measure soft tissue changes and apply it to measure the gingival margin position changes after restoratio...

Ceramic materials are harder than enamel and unless polished or glazed, may wear the opposing tooth enamel. However many clinicians advocate using zirconia with no veneering feldspathetic porcelain to reduce the occlusal reduction of the preparation. However the wear of glazed and polished zirconia functioning against the enamel of the opposing tee...

Introduction: Surface roughness can lead to excessive plaque accumulation, surface staining, and less than optimal esthetics. Objectives: This study was designed to compare changes in surface roughness value in enamel caused by infiltration resin. Methods: Freshly extracted molars were collected and cleaned using polishing cups and pumice to remove...

Impression Material Tear Strength Before and After Recommended Setting Time Clinically, if impression materials are removed from the mouth prior to the manufacturer's recommended setting time, thin portions of the impression might be susceptible to tearing. OBJECTIVES: This study measures the tear strength of two light-bodied polyvinyl siloxane...

Fixed orthodontic appliances and poor oral hygiene lead to enamel demineralization and unesthetic white spot lesions (WSLs). Objective: The purpose of this study was to create a model to measure continuing demineralization around resin infused human enamel WSL. Method: A resin infiltrating material, Icon, has been developed to treat WSLs in a minim...

To determine the effects of vitamin D receptor (VDR) deficiency on mouse dentin and enamel mineralisation, and how normalisation of serum calcium level affects dentin and enamel phenotypes in VDR knockout mice. Groups of VDR wild-type (VDR+/+), VDR deficient (VDR-/-) and VDR-/- rescued mice were sacrificed at 70.5 days of life. The rescued group wa...

Vitamin D plays an important role in bone mineralization. Enamel and dentin are two mineralized tissues of different origins that are part of the tooth structure, but the mechanism by which vitamin D regulates the mineralization of these tissues remains unclear. We examined the mineral deposition pattern of enamel and dentin in continuously eruptin...

Background and Objective Erbium lasers are potential tools to remove caries and dental hard tissue but bond strengths of composites to those preparations are reported to be lower than conventional methods. The purpose of this study was to evaluate the effect of mechanical excavation and/or chemical alteration on bond strength of composites to laser...

Metal transfer to femoral heads may result from impingement against the metallic acetabular shell following subluxation/dislocation, or when metallic debris enters the articulation zone. Such transfers roughen the head surface, increasing polyethylene wear in total hip replacements. Presently, we examined the surface roughness of retrieved femoral...

Postoperative dislocation of total hip replacements has been documented to occur at a rate of approximately 2.4–3.9% [1–3]. Such events may result in the transfer of titanium from the acetabular cup to the femoral head, both during the dislocation and surgical reduction of the dislocated joint [3,4]. If the head is reduced with this transfer presen...

Post fracture is a frequently reported failure for restored endodontically treated teeth. Current reports suggest that the rigidity of the post should be equal or close to that of the tooth structure in order to distribute the occlusal forces along the length of the root. OBJECTIVE: To determine and compare modulus of elasticity and flexural stre...

Objectives: To evaluate the property degradation of partially stabilized zirconia (PSZ) due to mechanical fatiguing both before and after aging. Methods: 20 partially stabilized zirconia bars (2x2x21) were separated into 4 groups: as-received, aged, fatigued, and aged-and-fatigued. Five partially stabilized zirconia discs (20 mm X 5mm) of the same...

Color stability, polish retention, and stain resistance are important esthetic properties for tooth colored restoratives. Objective: To measure and compare in vitro stain resistance, color stability, and gloss of resin-based composites (RBCs) and resin-modified glass ionomers (RMGIs). Methods: 30 samples (A2 shade, 12.5mm diameter X 3-3.2mm thi...

OBJECTIVE: To measure and compare cement shear bond strength to enamel, dentin, zirconia and feldspathic porcelain. METHODS: Enamel & Dentin: Teeth were trimmed and wet ground (320-grit SiC paper) to obtain flat enamel (80) and dentin (80) surfaces and randomly divided into 4 groups for enamel and dentin (n=10). Cercon: 40 discs (d=10mm/thickness...

Maintenance of marginal integrity of dental restorations is important in providing a long term seal. New self-etch composites are being developed to improve this adaptability. Objective: To assess the marginal seal of class V cavities restored with experimental self-etch flowable composite at enamel and dentin tooth-restoration interface. Metho...

Objective: To compare flexural strength, elastic modulus in two curing modes and crown retention of four cements Methods: Flexural strength and elastic modulus: Seventy specimens (27mmx2.5mmx2.5mm) were prepared using a Teflon split-mold following manufacturers' instructions. Thirty specimens (n=10) were light-cured and 40 were chemically-cured...

Vitamin D receptor (VDR) mutation has been reported to be associated with bone loss. In our previous studies, we found that VDR deficiency also results in abnormal mineralization of enamel and dentin. Furthermore, a high enamel mineralization density in the apical region of VDR deficient mouse incisor was observed. Since VDR deficiency also delays...

Vitamin D receptor (VDR) mutation has been reported to be associated with bone loss. In our previous study using an animal model, we found VDR deficiency significantly affects dentin maturation. We hypothesized that the VDR deficiency may affect the root formation. Objective: To compare the root formation in VDR deficient and wild type mouse mola...

Esthetic composite restorations easily lose gloss and marginal integrity. Liquid polishing systems have been introduced to counter these limitations, but the longevity of the layer subjected to toothbrush and dentifrice abrasion has not been measured. OBJECTIVES: This in vitro study evaluated the wear of liquid polishing systems using a toothbrus...

The formation of a superficial layer of tiny flakes has been observed on teeth prepared by Erbium lasers. It has been suggested that removing this layer (mechanically or chemically) may increase the bond strength of the resin composite. The purpose of this study is to evaluate the effect of various etching times on bond strength of resin composite...

Vitamin D plays an important role in the bone mineralization process. Enamel and dentin are two mineralized tissues of different origins that combine to form teeth, but the mechanism by which vitamin D regulates these tissues remains unclear. We hypothesized that vitamin D affects enamel and dentin mineralization through different mechanisms. To ex...

The use of highly cross-linked ultra-high molecular weight polyethylene in total hip arthroplasty has become a popular alternative to the use of conventional polyethylene. Evaluations with use of hip simulator tests1-4 and clinical evaluations of total hip replacements5-10 have independently shown that polyethylene materials processed with gamma ir...

Analyses of orthopaedic devices and prostheses from surgical revisions (failures) have provided considerable and valuable information related to the causes of some unintended clinical outcomes. Thousands of explanted samples have been categorized and hundreds studied over past decades. Forensic approaches for determining cause-effect relationships...

This study was performed to observe biofilm formation on dentin and to then observe effects of clinically achievable antimicrobial drug concentrations on these biofilms. Wild-strain endodontic bacteria were anaerobically cultured from necrotic pulps of extracted human teeth and used to grow biofilms on sterilized dentin slices in an anaerobic chamb...

Cadaveric Specimen Analysis of Hydroxyapatite Particulates, Bone, and Subperiosteal Implants P. BECK, and J. LEMONS, UAB School of Dentistry, Birmingham, AL Introduction: Subperiosteal implants continue to be utilized by some dental surgeons for the treatment of edentulous patients. A wide range of bone grafting biomaterials are also utilized in...

Surface characterization was performed to evaluate the surface condition of an uncoated cobalt alloy disc (control), and discs with medium and thick boron coatings for total joint articulating surfaces. Discs were characterized by scanning electron microscopy before and after dissolution studies. Chemical analyses of elemental transfer to the solut...

In vitro biocompatibility of diamond and boron for TMJ implants S.A. LUQUE1, P. BECK1, F. RAHEMTULLA1, Y. VOHRA2, and J. LEMONS1, 1University of Alabama, Birmingham, USA, 2University of Alabama at Birmingham, USA Purpose: To investigate the cytotoxicity of new biomaterial surfaces using a combination of standardized procedures based on human gingi...

1624 Tear Strength of Seven Elastomeric Impression Materials P. BECK, N.C. LAWSON, J.O. BURGESS, and L.C. RAMP, UAB School of Dentistry, Birmingham, AL, USA In clinical situations requiring impressions of tooth structure when margins are below the gingiva, a light bodied or extra light bodied hydrophilic impression material is often employed. In t...

In-vitro study of biocompatibility of diamond coating for TMJ implants S.A. LUQUE, P. BECK, F. RAHEMTULLA, Y. VOHRA, and J. LEMONS, University of Alabama, Birmingham, USA Purpose: Diamond as a biomaterial that has unique characteristics of high hardness, thermal conductivity, resistance to chemical attack and attachment as a coating to metals and...

Modular spine implants are used as an aid to obtaining fusion, but fretting and corrosion occur between modular components in a biologic environment. Forty-eight spinal implant constructs manufactured by a variety of companies were retrieved from 47 patients and were subjected to surface analysis stereomicroscopy. Stainless-steel implants (n = 23)...