bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Camera Angulation on Adaptation of CAD/CAM Restorations
Authors: PARSELL DOUGLAS E. , ANDERSON BRANDON C. , LIVINGSTON HAROLD M. , RUDD JEREMY I. , TANKERSLEY JERRY D. 
Published: July 2007

ABSTRACT Purpose: A significant concern with computer‐assisted design/computer‐assisted manufacturing (CAD/CAM)‐produced prostheses is the accuracy of adaptation of the restoration to the preparation. The objective of this study is to determine the effect of operator‐controlled camera misalignment on restoration adaptation. Materials and Methods: A CEREC 2 CAD/CAM unit (Sirona Dental Systems, Bensheim, Germany) was used to capture the optical impressions and machine the restorations. A Class I preparation was used as the standard preparation for optical impressions. Camera angles along the mesio‐distal and buccolingual alignment were varied from the ideal orientation. Occlusal marginal gaps and sample height, width, and length were measured and compared to preparation dimensions. For clinical correlation, clinicians were asked to take optical impressions of mesio‐occlusal preparations (Class II) on all four second molar sites, using a patient simulator. On the adjacent first molar occlusal surfaces, a preparation was machined such that camera angulation could be calculated from information taken from the optical impression. Degree of tilt and plane of tilt were compared to the optimum camera positions for those preparations. Results: One‐way analysis of variance and Dunnett C post hoc testing (α= 0.01) revealed little significant degradation in fit with camera angulation. Only the apical length fit was significantly degraded by excessive angulation. The CEREC 2 CAD/CAM system was found to be relatively insensitive to operator‐induced errors attributable to camera misalignments of less than 5 degrees in either the buccolingual or the mesiodistal plane. The average camera tilt error generated by clinicians for all sites was 1.98 ± 1.17 degrees.CLINICAL SIGNIFICANCEIt is unlikely that camera misalignment is a major source of error during the fabrication of simplistic CEREC 2 CAD/CAM restorations.
Effect of Alcoholic and Low‐pH Soft Drinks on Fluoride Release from Compomer
Authors: ABU‐BAKR NEAMAT H. , HAN LININ , OKAMOTO AKIRA , IWAKU MASAAKI 
Published: July 2007

ABSTRACT Purpose: The purpose of this study was to evaluate the amount of fluoride released from compomer restorative materials after immersion in various media. Materials and Methods: In this test, four materials were used: three compomers (Dyract, Dentsply, Konstanz, Germany; Compoglass, Vivadent, Schaan, Principality of Liechtenstein; and Xeno, Sankins, Tochigi, Japan) and one resin‐modified glass ionomer cement (Fuji II LC, GC, Tokyo, Japan). There were four test solutions: one alcoholic (whiskey), two low‐pH drinks (Coca‐Cola, orange juice), and one deionized water. Over a period of 60 days, the tested specimens were immersed in the test solution for 3 hours every day, then kept in deionized water. The fluoride released was detected by using a fluoride ion selective electrode connected to a microprocessor ion analyzer. The fluoride ion concentration (ppm) of the test solutions and deionized water was recorded after 1, 2, 3, 4, 7, 30, and 60 days. Electron probe microanalysis was used for surface analysis of the fluoride released. Results: When immersed in low‐pH soft drinks, compomer showed a significantly higher fluoride release than when immersed in deionized water (p <.0001). For specimens immersed in Coca‐Cola, the fluoride release levels (pg/cm2, mean ± SD) at 1, 7, and 60 days for Dyract (91.6 ± 1.8, 39.3 ± 3.1, 10.5 ± 0.9), Compoglass (129.5 ± 0.9, 66.5 ± 2.7, 19.0 ± 0.3), Fuji II LC (147.0 ± 4.2, 50.8 ± 3.1, 27.6 ± 3.0), and Xeno (73.6 ± 3.2, 27.3 ± 2.1, 6.6 ± 0.6) demonstrated the trend of significantly lower releases with time in water solution. Over a 60‐day period, materials immersed in 100% orange juice released the highest amount of fluoride, which could be attributable to the erosive effect of the medium. Materials immersed in deionized water released the least amount of fluoride. Among the tested compomers, Compoglass released the most fluoride.CLINICAL SIGNIFICANCEThe results of this study indicate that, at low pH, compomer restorative materials tend to release more fluoride.
Bioactive Glass Granules for Regeneration of Human Periodontal Defects
Authors: ROSENBERG EDWIN S. , FOX GREGORY K. , COHEN CHARLES 
Published: July 2007

ABSTRACT Purpose: A comparative study which evaluated the effectiveness of bioactive glass granules of uniform size (300–335 μm) for the regenerative treatment of interproximal intrabony periodontal defects was conducted. Materials and Methods: Twelve pairs of advanced periodontal lesions in 12 patients (6 males and 6 females) were treated in a split‐mouth design with open flap débridement in the control sites and open flap debridement with bioactive glass particles placed in the test sites. Results: At 6 months post‐treatment, both treatment modalities demonstrated a gain in clinical attachment level (CAL), with the test sites having a significantly (p < .01) greater gain in CAL than the control sites. Reentry procedures were performed to assess the amount of hard tissue fill. The test sites demonstrated significantly (p < .001) more gain in hard tissue fill than the controls.CLINICAL SIGNIFICANCEThe use of bioactive glass granules of uniform size in human interproximal intrabony periodontal defects resulted in significantly better hard tissue fill and clinical attachment gain than surgical debridement alone.
Color Stability of Compomer after Immersion in Various Media
Authors: ABU‐BAKR NEAMAT , HAN LINLIN , OKAMOTO AKIRA , IWAKU MASAAKI 
Published: July 2007

ABSTRACTPurpose:The purpose of this study was to evaluate the effect of various media on the color stability of compomer and to compare these results to those of other materials that could be used in similar clinical circumstances.Materials and Methods:In this test, six materials (shade A2) were used: four compomers (Dyract, Compoglass F, Xeno, F2000), one composite resin (Clearfil AP‐X), and one resin‐modified glass ionomer cement (Fuji II LC). There were four test solutions: one alcoholic (whiskey), two low pH soft drinks (Coca Cola, orange juice), and deionized water as a control. A plastic ring mold (9‐mm diameter x 1‐mm height) was used to prepare 120 disk specimens. For 60 days, the test specimens were immersed in the various media daily for 3 hours then transferred to the deionized water. Color was measured by CIE L* a* b* relative to CIE source against a white background, using a colorimeter. Color change (Δ*) was calculated as Δ*= [(δ*)2+ (δ*)2+ (Δ*)2]1/2. Color changes (Δ*) were recorded after 1, 7, 30, and 60 days.Results:The results indicated that compomer and resin‐modified glass ionomer were susceptible to discoloration in various solutions over an extended period of time. Composite resin showed minimal perceptible color change. Specimens immersed in whiskey showed a significantly high perceptible color change(p< .0001). Water caused no perceptible color changes.CLINICAL SIGNIFICANCECompomer and resin‐modified glass ionomer materials are susceptible to discoloration by various media.
Evaluating Porcelain Color Match of Different Porcelain Shade‐Matching Systems
Authors: WEE ALVIN G. , RANG EDITH Y. , JOHNSTON WILLIAM M. , SEGHI ROBERT R. 
Published: July 2007

ABSTRACT Purpose: This in vitro study was designed to evaluate the new ShadeEye‐EX Chroma Meter and a new visual porcelain shade‐matching system (Vitapan 3‐D Master, Omega 900) in comparison to the traditionally used visual porcelain shade‐matching system (Vita Lumin Vacuum, VMK 68). Materials and Methods: Shade matches and porcelain fabrications on individualized shade tabs were carried out. The fabricated porcelain tabs were evaluated against the respective natural tooth using the United States Public Health Service (USPHS) criteria to determine clinically acceptable match. The tabs also were ranked according to the final‐color match to the corresponding natural tooth. Results: The percentage of clinically acceptable color matches were as follows: Vita Lumin Vacuum (46.67%), ShadeEye‐EX (40%), and Vitapan 3‐D Master (56.67%). The generalized estimating equation (α= 0.5) showed no statistically significant difference between systems in obtaining a clinically acceptable match (p= .5729). The chi‐squared test (α= 0.5) showed no statistically significant difference between systems in terms of rank order (p= .5017). The two new systems do not produce color match that is better than the conventional visual porcelain shade‐matching system.CLINICAL SIGNIFICANCEBoth the shade‐matching environment and communication between dentist and technician should be optimized with use of visual and instrumental shade‐matching systems.
Effect of Distance on the Power Density from Two Light Guides
Authors: PRICE RICHARD B. , DÉRAND TORE , SEDAROUS MARY , ANDREOU PANTELIS , LONEY ROBERT W. 
Published: July 2007

ABSTRACT Purpose: This study determined the effect of distance on the power density from standard and Turbo light guides (Demetron/Kerr, Danbury, Connecticut). Materials and Methods: Power density was measured from 0 to 10 mm away from the tip of standard 8‐mm curved light guides and 13/8‐mm Turbo curved light guides. To determine the effect of distance on power density, a polynomial regression line was fitted. The Kolmogorov‐Smirnov (K‐S) statistic and the Wilcoxon rank sum (WR) tests were used to determine if there was a difference in the rate at which the power density decreased for the standard and Turbo light guides as the distance from the tip increased. Photographs of the light dispersion from each tip were also taken. Results: At 0 mm, the mean (± SD) power density from the two standard light guides was 743 ± 6.1 mW/cm2 and from the four Turbo light guides was 1128 ± 22.1 mW/cm2. As the distance from the tip of the light‐guide tip increased, the power density decreased, but the rate of decrease was greater from the Turbo light guides than from the standard light guides. At 6 mm the power density from the standard light guides fell to 372 mW/cm2 (50% of the original value) and the power density from the Turbo light guides fell to 263 mW/cm2 (23% of the original value). Both the K‐S statistic and the WR sum test indicated that the distribution of light intensities was significantly different from the two light guides (WR p‐value = .0246, K‐S p‐value < .0001). The two estimated polynomials intersected at 3.66 mm, and the 95% prediction intervals intersected at about 2.8 and 4.8 mm. Therefore, beyond 5 mm away from the tip of the light guide, the standard light guides gave higher power density readings than the Turbo light guides. Photographs showed that the light dispersed at a wider angle from the Turbo light guides than from the standard light guide.CLINICAL SIGNIFICANCEThe design of the light guide of a light curing unit affects light dispersion, power density, and ultimately the dentist's ability to properly cure composite. For these reasons, manufacturers should report the power density at the tip of the light guide and 6 mm from the tip of the light guide, since significant differences exist between light guide designs.
Polymerization Depths of Contemporary Light‐Curing Units Using Microhardness
Authors: RUEGGEBERG FREDERICK A. , ERGLE JANET W. , METTENBURG DONALD J. 
Published: July 2007

ABSTRACT Purpose: This research investigated composite depths of cure using a variety of light‐curing units and exposure protocols. Materials and Methods: Composite (Herculite XRV, shade A2, Kerr, Orange, California) was exposed in opaque compules to conventional quartz tungsten halogen (QTH) units, soft‐start units, high‐intensity QTH and plasma arc (PAC) curing lights, and one argon laser. Cured compules were sonicated to remove uncured composite and were sectioned and polished along the long axis to expose cured composite. Knoop hardness was measured 0.5 mm from the irradiated, top surface and then at 1.0 mm and in 1.0‐mm increments until reliable readings could no longer be obtained. Hardness values were compared by analysis of variance at similar depths within a specific curing‐light classification, using the hardness of the standard 40‐second conventional QTH exposure as comparison (Dunnett's t‐test). Depth of cure was defined as the deepest hardness value found equivalent to that at 0.5‐mm depth for a specific curing light and scenario. Results: Conventional QTH lights provided similar hardness profiles. At 2‐mm depth, use of a different unit or curing tip made no difference in hardness compared with the standard. At this depth, soft‐start (pulse‐delay and step‐cure) methods yielded hardness similar to that of the standard. High‐intensity QTH lights provided similar hardness at 2‐mm depth in 10 seconds to that of the standard 40‐second exposure. Plasma arc exposure for less than 10 seconds produced inferior hardness compared with the standard. A 10‐second PAC and a 5‐second laser exposure gave hardness at 2‐mm depth equivalent to that of the 40‐second standard. Depth of cure for almost all curing scenarios was not greater than 2 mm.CLINICAL SIGNIFICANCESimilar‐type conventional QTH lights with different tip diameter (8 and 12 mm) provide similar composite cure characteristics. Soft‐start techniques provide similar cure profiles to those achieved with conventional QTH technique when used according to manufacturer's recommendations. High‐intensity QTH units and the argon laser can reduce exposure time while providing composite with similar hardness to that of conventional QTH curing. Plasma arc exposure should be at least of 10 seconds duration to provide hardness equivalent to that achieved with conventional 40‐second QTH exposure. Even with consideration of high‐intensity curing units, composite increments should still be no greater than 2 mm to provide homogeneous hardness.
Learning to Smile: The Neuroanatomic Basis for Smile Training
Authors: TERRY DOUGLAS A. , PIRTLE PHILIP L. 
Published: July 2007

ABSTRACTThis article demonstrates that although any layperson could recognize that the smile manifests mainly in the oral and periorbital regions, a comprehension of the neurologic and musculoskeletal elements lends the clinician insight into the many aspects of a smile. The neurologic control of a smile consists of a complex process involving many facets. As with any other complex neuromuscular activity, repetitions of the act can train the central nervous system, neural network, and muscular network in efficient performance of and correct musculoskeletal activation involved in the act itself. With functional knowledge of muscles dedicated to a pleasing full smile, together with a battery of easy and effortless exercises, the clinician is able to help the patient change behavior intended to camouflage perceived oral flaws. A patient needs reassurance that behind the guidance from the clinician lies medical evidence that such routine movement of muscles will indeed improve the smile. When asked why or how the exercise succeeds, the clinician can reassure the patient based on a working knowledge of the neurologic and muscular anatomy involved.CLINICAL SIGNIFICANCEA functional knowledge of muscles dedicated to a pleasing full smile, together with a battery of easy and effortless exercises, provides the clinician with the ability to assist the patient in altering years of behavior intended to camouflage perceived oral flaws.
Minimum Color Differences for Discriminating Mismatch between Composite and Tooth Color
Authors: RAGAIN JAMES C. , JOHNSTON WILLIAM M. 
Published: July 2007

ABSTRACT Purpose: The purpose of this study was to determine if there are differences between patients and dental professionals in their ability to identify small color differences (AE) in composite resin restorative materials in vitro and to determine the AE that would indicate acceptability of color match between a restoration and an adjacent tooth. Materials and Methods: Subjects were asked to evaluate composite resin disks to distinguish acceptability of ΔE between disk pairs. Color difference discrimination of dental professionals groups D1 (dentists, n = 12) and D2 (dental auxiliaries, n =12) was compared to that of dental patient groups P1 (patients, n = 12) and P2 (scientists, n = 12). Each group was pretested for normal color vision. Color differences between a standard and restoration disks of composite were measured in Colour Measurement Committee (CMC) (1:1) color units. Data were analyzed by logistic regression, and results were used to calculate a probability level for minimal acceptance or rejection of ΔE for all observers. Mean 50:50 ΔE replacement points (RP) for each group were obtained and analyzed by analysis of variance, and the Tukey pairwise comparison test was applied (α= 0.05 for all statistical analyses). Results: There were significant differences found between the experimental groups (p= .020). Group D2 (mean 50:50 ΔE RP = 1.78) proved to be more discriminating in accepting differences between tooth and composite resin restorative material color than group P1 (mean 50:50 AE RP = 2.69). The mean 50:50 ΔE RP for all subjects was 2.29 CMC (1:1) units.CLINICAL SIGNIFICANCEThe ability to generate an excellent color match between a tooth‐colored restoration and the tooth is critical to esthetic success. This study demonstrates that patients are not as discriminating in their ability to identify small color differences between composite restorations and the tooth as are dental professionals. Dental auxiliaries proved to be more discriminating in accepting differences between tooth and composite resin restorative material color than were patients.
The Science of Communicating the Art of Esthetic Dentistry. Part III: Precise Shade Communication
Authors: DERBABIAN KRIKOR , MARZOLA RICCARDO , DONOVAN TERRY E. , ARCIDIACONO ALESSANDRO 
Published: July 2007

ABSTRACTShade matching is inherently complex and involves understanding the science of color, determining the shade and surface characteristics of teeth, and communicating this information to the laboratory technician. The laboratory technician then has the difficult task of mimicking the selected shade and ultimately reproducing it in the final restoration.CLINICAL SIGNIFICANCEThis article describes several methods of communicating and several tools that are available to the restorative dentist to achieve the esthetic results desired. By using these simple techniques, the dentist and laboratory technician are better able to communicate the shade and surface characteristics of teeth.
Comparison of Color of Resin Composites of White and Translucent Shades with Two Shade Guides
Authors: LEE YONG‐KEUN , LIM BUM‐SOON , KIM CHEOL‐WE , POWERS JOHN M. 
Published: July 2007

ABSTRACT Purpose: The purpose of this study was to compare the color of resin composites of white, translucent, and conventional shades with shade guides, based on the analysis of the color distribution of shade guides. The influence of color measuring mode, specular component included (SCI) or excluded (SCE), was also determined. Materials and Methods: The labial portions of shade guide tabs (Vita and Chromascop) were polished flat with up to 2400‐grit SiC paper. Color coordinates were measured according to CIE L*a*b* color scale on a reflection spectrophotometer with both the SCE and SCI modes. The color coordinates of white, translucent, and conventional shades of two brands of resin composites were measured and compared with those of the shade guides. Results: There was no logical order in the color distribution of the two shade guides. The color of white and translucent shades of resin composites was located on the low CIE a* and CIE b* value area. The CIE L*, a*, b* values of resin composite with the same color designations were different, depending on the brand of material. The color difference (AE*) of shade guides by the measuring mode (SCE vs. SCI) was between 3.2 and 6.5.CLINICAL SIGNIFICANCEA new systematic shade guide including the new white or translucent shades of resin composites should be made, based on the logical distribution of colors. The color difference caused by the color measuring mode should be considered in color measurement of esthetic restorative materials and in the design of the shade guide. Also, regardless of the brand of materials, there should be unification of shades for consistent clinical result.
Esthetic Considerations in Removable Prosthodontics
Authors: DONOVAN TERRY E. , DERBABIAN KRIKOR , KANEKO LESLIE , WRIGHT ROBERT 
Published: July 2007

ABSTRACTPatients requiring extensive replacement of teeth with removable prostheses are indeed esthetic orphans in many contemporary dental practices. Although the advent of successful osseointegration has dramatically reduced the need for removable prostheses, there are still many patients who for health, anatomic, psychological, or financial reasons are not candidates for implants. These patients deserve the same level of esthetic restorative dentistry as those who are restored with fixed prostheses. Clearly, the restorative dentist has the greatest flexibility from an esthetic standpoint with complete dentures. Soft and hard tissues can be replaced with contemporary characterized denture‐base materials, and a truly infinite variety of tooth forms, shades, and arrangements can be used to meet the expectations of the most demanding patient. For partially edentulous patients, the major problem is designing a removable partial denture that avoids the unsightly display associated with conventional clasp assemblies. There are strategies available to accomplish this effectively while establishing an environment for optimal periodontal health, and to minimize destructive stresses on the abutment teeth.CLINICAL SIGNIFICANCEThis article discusses the procedures essential for providing an upscale, quality esthetic service with removable prostheses. Effective strategies to eliminate unsightly clasp assemblies with removable partial dentures are described.
Dental Color Standards: Shade Tab Arrangement
Authors: PARAVINA RADE D. , POWERS JOHN M. , FAY ROSE‐MARIE 
Published: July 2007

ABSTRACT Purpose: The aim of this study was to analyze the shade tab arrangement of two popular dental shade guides, suggest possible improvements, and propose clinical guidelines. Materials and Methods: Data were recorded using a colorimeter set to standard illuminant source C and CIE L*a*b* system. The manufacturers' shade tab arrangement as well as the possible improvements in the arrangement of shade tabs of Vitapan Classical and Vitapan 3‐D Master (Vita Zahnfabrik, Bad Säckingen, Germany) shade guides were examined by regression analysis. Results: Certain shortcomings in the manufacturers' arrangement of both color standards were observed. The Vitapan 3‐D Master arrangement was more consistent, but with a decrease in lightness, tab saturation decreased as well in four of its five groups. When Vitapan Classical and Vitapan 3‐D Master tabs were arranged according to ΔE* in relation to the lightest tab, r2 was 0.98 and 0.96, respectively. After dividing the total ΔE* range into four equal segments for the newly established Vitapan Classical guide, r2 was 0.91, 0.95, 0.68, and 0.94, respectively. Corresponding r2 values for Vitapan 3‐D Master were 0.96, 0.94, 0.90, 0.94, and 1.0.CLINICAL SIGNIFICANCETotal color difference in relation to the lightest tab, followed by the tab division into an adequate number of groups, is recommended as a possible and universally applicable mode of tab arrangement in dental color standards.
Posterior Resin‐Based Composite Restorations: Clinical Recommendations for Optimal Success
Authors: RITTER ANDRE V. 
Published: July 2007

ABSTRACTResin‐based composites are increasingly used for the restoration of defects in posterior teeth. This review describes, illustrates and discusses important clinical aspects of the posterior composite technique. A relatively new stratification concept oriented to the development of functional and anatomic restorations is proposed.