bluuebunny/crossref_metadata_2025 huggingface dataset:
THE CHOICE OF THE AGGREGATION LEVEL IN THE ESTIMATION OF QUARTERLY NATIONAL ACCOUNTS
Authors: Cainelli Giulio , Lupi Claudio
Published: March 2005

Many central statistical offices use indirect time series disaggregation methods to produce quarterly national accounts estimates or other high frequency variables. This paper investigates the relation existing between the statistical properties of indirectly estimated time series and the contemporaneous aggregation level at which estimation is carried out, when a version of the Chow‐Lin (1971, 1976) method is used to evaluate quarterly time series. It is shown that estimation at the lowest possible level of contemporaneous aggregation is not always optimal. In order to choose the level of contemporaneous aggregation at which time series disaggregation should be carried out, the use of formal econometric tests is suggested.
INTERGENERATIONAL INCOME MOBILITY IN SWEDEN: WHAT DO TAX‐DATA SHOW?
Authors: ÖSterberg Torun
Published: March 2005

The aim of this paper is to investigate intergenerational income mobility in Sweden by means of a representative sample drawn from tax‐data files. Longitudinal data on actual parent‐child pairs spanning 1978–92 are employed. Regression and correlation coefficients are analyzed and transition matrices calculated in order to investigate income mobility over generations. The results achieved show high intergenerational income mobility in Sweden between fathers and sons in comparison to estimations performed in most other countries and more especially compared to the U.S. This indicates that Sweden does not only have lower cross‐sectional income inequality, but also higher intergenerational income mobility than those countries. The mother's earnings influence children's earnings less than the father's. However, the mother's earnings correlate more strongly with a daughter's earnings than they do with that of a son. The major indication of immobility across generations is found in the upper income deciles.
DEMOGRAPHIC TRENDS AND CONSUMPTION INEQUALITY IN AUSTRALIA BETWEEN 1975 AND 1993
Authors: Barreti Garry F. , Crossley Tomas F. , Worswick Christopher
Published: March 2005

We examine trends in consumption inequality among Australian households using the Australian Bureau of Statistics Household Expenditure Surveys collected over the period 1975 to 1993. We find that the distribution of consumption is much more equal than that of income and that both income and consumption inequality rose by significant amounts over the period. However, consumption inequality rose by much less (the Gini coefficient for income inequality rose by 17 percent while that for nondurable consumption rose by 9 percent). We then examine the effects of demographic trends, specifically population aging and changing family structures, and find they account for only a minor fraction in the overall growth in economic inequality.
Nontraumatic Final Impressions for Fixed Partial Dentures
Authors: Hoffman Jules M.
Published: March 2005

A nontraumatic, nonretraction impression technique is presented which uses the fabrication of an acrylic resin shell from an interocclusal wax impression. A crucial step in the procedure is obtaining the complete finish line of the preparation within the resin. This tray, which is filled with an elastomeric impression material, is combined with a triple tray of the same material to provide all the necessary relationships to construct a crown or coping. This procedure is especially efficient for multiple abutments during fixed partial denture construction.
Initial Tolerance and Tissue Response to Complete Dentures by Diabetic Patients
Authors: Soderstrom Peter T. , Seals Richard R. , Morrow Robert M. , Murrah Valerie A. , Barnwell George M.
Published: March 2005

Purpose The oral effects of diabetes in dentate patients have been studied extensively, but little clinical data has been collected with regards to edentulous patients who have diabetes. The purpose of this study was to investigate whether there are differences between diabetic and nondiabetic patients in initial patient tolerance and tissue response to complete dentures.

Materials and Methods Complete dentures were constructed for 62 diabetic and 56 nondiabetic patients. Treatment followed accepted prosthodontic principles recommended for diabetic patients. Twenty‐four hour and 1 week post‐placement appointments consisted of a patient questionnaire, intraoral examinations and indicated adjustments. The variables studied were the differences between responses to the questionnaire and the frequency of type, location, and size of clinically visible areas of mucosal irritation reported on standardized tissue evaluation forms.

Results Analysis of the responses to the questionnaire indicated diabetic patients reported xerostomia more often than nondiabetics. There were no statistically significant differences in initial tissue response to new complete dentures between the diabetic and nondiabetic patients. A statistically significant difference in tissue response was reported within the diabetic group, significantly fewer diabetic patients exhibited oral irritations at the second examination than at the first examination.

Conclusions The results of the present study indicate that when prosthodontic principles recommended for diabetic complete denture patients are followed, there are no clinically significant differences between diabetic and nondiabetic patients in initial patient tolerance and tissue response to complete dentures.
Porcelain‐Fused‐to‐Metal Pontics for Improved Removable Partial Denture Esthetics
Authors: Mansueto Michael A. , Anderson John A.
Published: March 2005

A removable partial denture fabrication technique that uses custom‐constructed porcelain fused‐to‐metal (PFM) pontics is described. PFM pontics enhance the dentist's shade matching effort in esthetically demanding situations.
Retention Loss of Implant Attachments: A Case Report
Authors: Matthews Kate E. , Chambless Lewis A. , Staffanou Robert S.
Published: March 2005

Smokeless tobacco in conjunction with a persistent habit pattern resulted in dramatic loss of retention with a Zest‐type implant attachment. (Zest Anchors, Inc, Escondito, CA).
Commissure Burn Splints: Literature Review and Prefabrication Technique Using a Visible Light–Cured Resin
Authors: Elton William C. , Meyer Jack B. , Nagy William W. , Knudson Rodney C.
Published: March 2005

Commissure burn splints reduce or eliminate the need for reconstructive surgery after injury to the perioral tissues. The literature describes the injury, immediate care, and splint treatment modalities. A technique to construct a prefabricated commissure burn splint from visible light cure resin and orthodontic wire is presented. Passive or dynamic retraction may be obtained by varying the tension of circumcranial orthodontic headgear or adjusting Velcro placed on a Velfoam strap.
The Effect of the Articulator Settings on the Cusp Inclines as Measured by a Coordinate Measuring Machine
Authors: Wagner A. George , Rennels Kenneth E.
Published: March 2005

Purpose The purpose of the study was to learn the effect of changes in the articulator settings on the cusp angles during working, nonworking, and protrusive movements; the purpose was also to determine the ability of the coordinate measuring machine to measure the movements.

Materials and Methods The condylar angles and the anterior guide angles on a Hanau 96H2 articulator (Teledyne Hanau Corp, Buffalo, NY) were varied; 432 working, nonworking, and protrusive cusp angles were measured at the first molar by a coordinate measuring machine.

Results The data from the coordinate measuring machine was used to produce formulas. The formulas were used to calculate the working, nonworking, and protrusive cusp angles that will occur as a result of 72 different articulator settings.

Conclusions The coordinate measuring machine is useful for making measurements of articulator movements. Additional research may measure the movements of other articulators or compare articulators (such as the arcon and nonarcon).
Evolution of Occlusion and Occlusal Instruments
Authors: Becker Curtis M. , Kaiser David A.
Published: March 2005

All occlusal concepts are based, in part, on theory, and all theories may have borrowed from the past. This article reviews the evolution of occlusal concepts to understand how differing theories interrelate, where they agree, and where each concept contributed to the ongoing understanding and evolution of occlusion principles. Also, the flexible and practical concept of biologic occlusion is presented. The philosophy of biologic occlusion is one that functions in health. The goals of biologic occlusion are also presented.
Adding Retentive Features in the Rebonding of Cast Metal Resin‐Bonded Prostheses
Authors: Duncan J. David , Reeves Gary W. , Fitchie James G.
Published: March 2005

Many methods have been used to improve retention in resin‐retained fixed prostheses, such as electrolytic etching of the retainer, the labial wrap design, proximal grooves, cast pin retention, and the use of improved adhesive resins such as Panavia EX (Kuraray Co, Osaka, Japan). Insufficient retentive features often lead to debonding of resin‐retained fixed prostheses. Debonded prostheses may occasionally be recemented and successfully retained by the addition of retentive features to the prosthesis and abutment teeth. When recementing a debonded prosthesis with questionable retention, additional retention may be added to the retentive wings of the prosthesis by using a Rochette retentive hole in combination with pin retention or enamel/dentinal slots in the abutment teeth.
Evaluation of Polycaprolaitone Custom Tray Material
Authors: Pilcher Elizabeth S. , Draughn Robert A.
Published: March 2005

Custom impression trays are necessary for accurate impressions in fixed prosthodontics when using polysulfide impression materials. These custom impression trays are needed to provide for a uniform thickness of impression material to minimize distortion. Custom impression trays have historically been made from acrylic resin. New materials have been developed as alternatives to acrylic resin, and this study evaluates one product currently available that is composed of polycaprolaitone. This study evaluates the modulus of elasticity of polycaprolaitone as compared with acrylic resin, and also evaluates the amount of permanent deformation of the new material when placed under a load. The elastic modulus of polycaprolaitone was tested using three‐point bending of specimens placed in a universal mechanical test system. The elastic modulus of the new material was found to be significantly lower than that of acrylic resin. The next test evaluated the amount of permanent deformation of the polycaprolaitone material when specimens approximating the shape and size of custom impression trays were placed under a load. These trays were placed in a universal mechanical test system and differing loads were placed on them. Results showed that although the trays deformed at relatively low loads, all deformation was fully recovered within a clinically insignificant period of time (less than 30 seconds). From these experiments it was concluded that although the polycaprolaitone material has a lower modulus of elasticity and will deform under relatively low loads, the material recovers completely, and thus the deformation would not interfere with the clinical performance of polycaprolaitone as a custom tray material.
An Alternative to the Altered Cast Procedure
Authors: Hoffman Jules M.
Published: March 2005

A simplified method is described for achieving the purpose of the altered cast technique without the inherent laboratory problems of realignment of the metal framework on a modified cast and the extra time involved.
Bonding Soft Reline Materials to Base Metals
Authors: Jackley Gregory A. , Plummer Kevin D.
Published: March 2005

Purpose

In the past it has been difficult to treat soft tissue changes occurring beneath metal frameworks of removable partial dentures or complete dentures using soft reline materials. The main difficulty has been in getting the resilient materials to adhere to the metal. This research investigates the use of microabrading with and without a universal resin bonding system in achieving a clinically useful bond between two soft reline materials and a commonly used base‐metal alloy.

Materials and Methods

120 disks, 1 inch in diameter, were cast in Ticonium (CPM Industries, Albany, NY). The surface of the disks was finished to a high polish and then evenly microabraded. Four test groups of 15 pairs of disks were established, with two groups receiving Coe‐Soft (Coe Laboratories, Chicago, IL) and two groups receiving Soft Oryl (Teledyne Getz, Elk Grove Village, IL). One group of each reline material had the microabraded surfaces on each disk treated with All Bond 2. Then, 1.2 mm of reline material was placed between each set of disks and allowed to cure. The disks were placed on an Instron machine and a tensile force was applied until bond failure occurred.

Results

All four groups showed significant bond strengths, with the Soft Oryl groups showing statistically significant higher bond strengths. In both reline material groupings, the groups with only microabrading showed slightly higher bond strengths.

Conclusions

Soft reline materials can be made to adhere to base‐metal alloys used in removable prosthodontics with clinically acceptable strengths using microabrading with or without the use of a resin bonding system.
An Investigation of the Impac Custom Abutment for Root Form Dental Implants
Authors: Mante Francis K. , Seckinger Robert J. , Purinton Dennis , Abreu Samuel J. A. , Berthold Peter
Published: March 2005

Purpose

This study measured the tensile force required to separate a custom implant abutment fixture that had been cast onto a machined component using the Impac custom abutment system (Vident, Baldwin Park, CA). The characteristics of the interface between the cast and machined components were also investigated by scanning electron microscopy x‐ray and energy‐dispersive (JEOL T330A, Peabody, MA) analysis (Kevex Delta Level 1, San Carlos, CA).

Materials and Methods

A polycarbonate custom abutment component, attached to a gold alloy component of the abutment, was invested in a phosphate‐bonded investment and cast in a type III gold alloy (Argenco, Argen Precious Metals, San Diego, CA). Eight samples were cast after a burn‐out of 900°F and 13 samples were cast after a burn‐out at 1300°F. The abutment components were pulled in tension in a universal Testing Machine (Instron 4204, Canton, MA) until failure. The interface of as‐cast and failed samples were examined by electron microscopy.

Results

Samples burned out at 1300°F failed at a mean force of 2477 ± 295 N (545 ± 65 Ib), and samples burned out at 900°F failed at a mean force of 2182 ± 91 N (484 ± 20 Ib). Electron microscopy of the interface between the cast and machined components showed retentive tags provided in the design of the machined components. There was also a zone of diffusion between components shown by a zone of void formation within the casting. Failure occurred at the interface of the cast and machined components for all samples.

Conclusions

The cast component was retained by a combination of mechanical and chemical mechanisms.
In Vitro Analysis of the Effects of Two Air‐Abrasive Prophylaxis Systems and Inlet Air Pressure on the Surface of Titanium Abutment Cylinders
Authors: Razzoog Michael E. , Koka Sreenivas
Published: March 2005

Purpose

The purpose of this study was to investigate the effects of two air‐abrasive prophylaxis systems and the effect of inlet air pressure on the surface of Brånemark titanium abutment cylinders.

Materials and Methods

Single abutment cylinders were treated with either the Prophy‐Jet system (sodium bicarbonate abrasive) (Dentsply International, York, PA) or the Microprophy system (aluminum oxide abrasive) (Danville Engineering Co, Danville, CA) for 60 seconds at an inlet air pressure of 60 psi or 90 psi. The effects on the surface of each abutment cylinder were visually inspected by scanning electron microscopy.

Results

A comparison of abutment cylinder surfaces after treatment showed that the Prophy Jet system removed machining marks to a greater degree than the Microprophy system. Sodium bicarbonate particles from the Prophy‐Jet system were significantly larger than the aluminum oxide particles used with the Microprophy system, potentially accounting for the difference in abrasivity. In addition, inlet air pressure of 60 psi caused removal of machining marks to a greater degree than an inlet air pressure of 90 psi. The principle of phase separation may account for the lower inlet air pressure causing more removal of machining marks than the higher inlet air pressure.

Conclusions

Under the experimental conditions tested, neither of the two systems tested seemed to cause significant abrasion of the surface of titanium abutment cylinders.
A Comparison of Two Silicoating Techniques
Authors: Hummel Susan K. , Pace Larry L. , Marker Victoria A.
Published: March 2005

Purpose

A major challenge of composite‐coated metal restorations is creating a strong bond between the two materials. This study was conducted to compare the bond strengths between composite and metal alloys using two silicoating treatments; the Silicoater Classic and the Silicoater MD (Kulzer Inc. Irvine, CA).

Materials and Methods

The Classic uses a pyrolytically applied silica glass and the MD process is an oven sintering of a metal oxide silicate layer. Two types of specimens of three different alloys were cast (Deva4: 51Au38Pd, G‐Cast: 50Au32Ag12Cu [Degussa Corp, South Plainfield, NJ]; Ticonium: 70Ni15Cr [CMP Industries, Inc, Albany NY]). The specimens were silicoated with either the Classic or the MD process and opaque resin and composite (Dentacolor, Kulzer Inc) were bonded to each surface. A total of five control and 10 thermocycled (5,040 cycles, 0°C to 67°C; dwell time, 1 minute) specimens were fabricated for each alloy and specimen type. Two bond strength tests were used; a three‐point flexure test and a shear bond strength test. Data were analyzed using a multivariate analysis of variance (MANOVA) and a Tukey's multiple comparison test.

Results

The standard deviations of the shear bond strength values ranged from ± 2.30 to ± 17.62 kg; thus, there was no significant difference in these results. Bond strength ratios were calculated from the flexure strength data. After thermocycling, the Silicoater MD produced significantly higher (P < 0.05) bond strength ratio values compared with the Silicoater Classic for Deva‐4 (MD, 9.6 ± 1.5 v Classic, 4.7 ± 0.9) and G‐Cast (MD, 11.6 ± 1.2 v Classic, 3.9 ± 0.5) but lower values for Ticonium (MD, 4.5 ± 0.4 v Classic, 6.9 ± 0.9).

Conclusion

The Silicoater MD produced higher bond strength ratio values with noble alloys, and the Silicoater Classic produced higher bond strength ratio results when base metal alloys were used, suggesting a possible correlation between the effectiveness of the coating processes and the compositions of the alloys. These findings suggest that, for optimum results, selection of the type of silicoating process should be based on the components of the alloy.
Bond Strength of Adhesive Composites to Dental Substrates
Authors: Berry Ebb A. , Powers John M.
Published: March 2005

Purpose

The purpose of this study was to evaluate the in vitro bond strength of adhesive and traditional composites to several materials that might be encountered in clinical practice.

Materials and Methods

An adhesive composite, an adhesive composite with a bonding agent, and a traditional composite with a bonding agent were bonded to enamel, dentin, amalgam, porcelain, and nickel‐chromium‐beryllium (Ni‐Cr‐Be) alloy. Tensile bond strengths were determined after 24 hours storage at 23°C or thermocycling.

Results

The use of an adhesive composite with a bonding agent resulted in increased bond strength to amalgam, porcelain, and dentin, but not to enamel or Ni‐Cr‐Be alloy at 23°C, when compared with the adhesive composite alone. The adhesive composite with a bonding agent had higher bond strengths to amalgam, porcelain, and dentin than did the traditional composite with bonding agent, but not to enamel or Ni‐Cr‐Be alloy at 23°C.

Conclusions

The use of a bonding agent with an adhesive composite produced higher bond strengths than the adhesive composite alone. The traditional composite bonded better to enamel and Ni‐Cr‐Be alloy than did the adhesive composite. Thermocycling generally had no effect on bond strengths or increased them slightly.
Interdependence of the Hue, Value, and Chroma in the Middle Site of Anterior Human Teeth
Authors: Schwabacher William B. , Goodkind Richard J. , Lua Marie J. R.
Published: March 2005

Purpose

This study examines how the color coordinates of human teeth are related to each other and describes a mathematical relationship between Hue, Value, and Chroma of the middle site of anterior teeth.

Materials and Methods

The color coordinates obtained from a previous instrumental survey of the colors of vital teeth (see Goodkind and Schwabacher8) were examined statistically, and equations were sought to describe their distribution in color space. The resulting single equation was applied to the colors of 100 extracted teeth.

Results

Correlations between Hue, Value, and Chroma were not significant for incisal and cervical sites. For the middle site, these Munsell color coordinates were highly correlated and closely confined to a planar region of the color space, described by a single equation.

Conclusions

Human tooth color distribution seems to be relatively simple, at least for the middle site. It seems possible that a systematic method of shade selection (see Goodkind and Loupe15) can be made available.
Digital Imaging of Occlusal Contacts in the Intercuspal Position
Authors: Sakaguchi Ronald L. , Anderson Gary C. , DeLong Ralph
Published: March 2005

Purpose

The purpose of this study was to develop an approach to the measurement of occlusal contact area and location using digitized video images of occlusal records.

Materials and Methods

Five occlusal records in the intercuspal position were made using a polyvinylsiloxane material on five subjects with intact, natural dentition. In regions of occlusal contact, the material showed a minimal film thickness without perforation. A dental cast of the mandibular arch was video digitized and followed by digitization of each of the five occlusal records in place on the cast. An impression of a calibration stepwedge was video digitized to provide the relationship between impression material thickness and pixel density.

Results

Contact surface areas ranged from 0.02 to 3.16 mm2 between subjects. The contact positions on a single tooth determined in five records from a single individual showed coefficients of variation between 7.4% to 36.1%. Large variations in contact size were found in this group of five records from a single individual (coefficient of variation ranged from 10.8% to 156.7%). The large difference in contact size between records may be due to variations in biting force at the time the records were made. When the cast position was changed and records redigitized, the mean area of the contact was not significantly different (P > .20) from measurements at the original position.

Conclusions

For the small sample evaluated, a large variation in occlusal contact size was found in the five records. The occlusal contact location was consistent in the five records. The measurement method developed seems to provide reliable measures of occlusal contact surface area and location.
The Use of Ceramic Orthodontic Brackets as Rest Seats for Removable Partial Dentures
Authors: Counts Amy L. , Hopkins Aubrey R.
Published: March 2005

Ceramic orthodontic brackets were developed for the purpose of esthetics and increased tooth‐to‐bracket strength. An alternative method of preparing a rest seat on the lingual surface of lower canine teeth without violating the entemel integrity is offered. Ceramic orthodontic brackets were bonded to the lingual surfaces of mandibular canines and shaped into rest seats using diamond burs. Because the rest seats are not cut into the tooth structure, sensitivity and potential caries complications are avoided. The bracket is adhered to the tooth surface with a dimethacrylate bonding material. The brackets are bonded with either a no‐mix or a two‐part adhesive system. The strength of this bond will easily support the forces of a partial denture framework. The advantage over metal acid–etched retained rests is that this method avoids a time‐consuming laboratory step. The greatest advantage over the use of composite resins that are shaped into rest seats is the much higher bond strength. After ceramic brackets were bonded to the lingual surfaces of mandibular canines and shaped into rest seats, an impression was obtained for the fabrication of a conventional partial denture framework.
Partial Denture Framework Design for Bone‐Grafted Mandibles Restored With Osseointegrated Implants
Authors: Jacob Rhonda F. , King Gordon E.
Published: March 2005

Unilateral osseous reconstruction of a dentate mandible after tumor ablation may be restored with implants and a removable partial denture. Often the remaining dentition is in a “straight line” that does not allow cross‐arch stabilization of the framework. Framework design incorporating existing unilateral lingual or buccal retention in the natural dentition and unilateral implant attachments affords a stable, retentive definitive prosthesis for this patient population.
The Fracture Toughness of Various Core Materials
Authors: Ziebert Anthony J. , Dhuru Virendra B.
Published: March 2005

Purpose This study determined the fracture toughness of four core buildup materials.

Materials and Methods Single‐edge notch, bar‐shaped specimens conforming to the American Society for Testing Materials standard E‐399 were fabricated for a high copper amalgam alloy, two composite resins, and a glass ionomer buildup material. The specimens were stored in air for 1 week and then tested in three‐point bending mode with an Instron Universal Testing Machine (Instron Corporation, Canton, MA).

Results Fracture toughness values obtained were as follows: Fluorocore (composite resin; Caulk, Milford, DE), 1.54 MN · m−1.5; Ti‐Core (composite resin and titanium; Essential Dental Systems, New York, NY), 1.34 MN · m−1.5; Valiant Ph.D. (amalgam; Caulk), 1.29 MN · m−1.5; and Coreshade Glass lonomer Base Cement (Shofu Inc, Kyota, Japan), 0.55 MN · m−1.5.

Conclusions Glass ionomer materials are probably unsuitable as core buildup materials because of their relatively low fracture toughness. Fluorocore, Ti‐Core, and amalgam all had fracture toughness values significantly greater than the glass ionomer (P < .01).
Fabrication and Use of an Intracavitary Radiotherapeutic Applicator for the Posterior Sinus Wall: A Case Report
Authors: Lyzak William A. , Fleming Terence J.
Published: March 2005

The essential features of and the prosthodontic procedures necessary for fabricating a radiation applicator from dental acrylic resin for use in a clinical case of recurrent squamous cell carcinoma treated by intracavitary radiotherapy are described. A method for reducing radiation dose to the optic chiasm using Cerrobend alloy is presented.
Long‐term Clinical Performance of Resin‐Bonded Fixed Partial Dentures Placed in a Developing Country
Authors: Mudassir Abdul , Aboush Yousef E.Y. , Hosein Mervyn , Hosein Tasleem , Padihar Inayatullah
Published: March 2005

Purpose This study assesses the clinical performance of 92 resin‐bonded fixed partial dentures (FPDs) placed at four private practices in Karachi, Pakistan, between 1982 and 1991.

Materials and Methods The distribution of the FPDs was 9 perforated, 45 electrolytically etched, and 38 silicoated. Twenty‐five FPDs replaced anterior teeth and 67 replaced posterior teeth. There were 66 FPDs with single pontics and 26 with multiple pontics. The perforated designs used a restorative composite for cementation, whereas the electrolytically etched and silicoated designs used a composite luting cement. The observation periods for the perforated, electrolytically etched, and silicoated FPDs were 114,99, and 30 months respectively.

Results During the evaluation period, 27 FPDs (29%) failed; of these, 4 were perforated, 18 were electrolytically etched, and 5 were silicoated. The mean (±SD) duration of the successful clinical service for all FPDs was 41 ± 26 months. The mean time to failure for the FPDs that did not survive was 35 ± 23 months. The silicoated FPDs tended to have early failure, as did the FPDs with multiple pontics and those in the mandibular arch. Anterior and posterior FPDs performed equally well.

Conclusions These findings, in conjunction with those from Europe and North American, show that resin‐bonded FPD technology is as successful in a developing country as in industrialized areas of the world.
In‐Ceram Failure Behavior and Core‐Veneer Interface Quality as Influenced by Residual Infiltration Glass
Authors: Carrier David D. , Kelly J. Robert
Published: March 2005

Purpose Crown and fixed partial denture fabrication using In‐Ceram all‐ceramic restorative material (Vita Zahnfabrik, Bad Säckingen, Germany) involves the veneering of a glass‐infiltrated alumina core with porcelain. The manufacturer instructs that excess infiltration glass be removed from all core surfaces before porcelain application; however, meticulous removal may not be practical. This study evaluates the failure behavior of two different types of In‐Ceram structures with or without thin layers of excess infiltration glass left on core surfaces.

Materials and Methods Two groups of porcelain‐veneered incisor crowns were fabricated having either (1) excess infiltration glass removed from the aluminous core (n = 10) or (2) a thin layer (0.1 to 0.3 mm) of excess glass remaining on the core (n = 10). Each crown was loaded on its incisal edge against a flat compression platen at 0.5 mm/min. Two groups of core disks (thickness, 1 mm; radius, 7.5 mm) underwent similar surface treatments; ie, group A as recommended (n = 15) and group B having excess glass (n = 15). Disks were veneered with porcelain, polished to 1.5 mm, and loaded in biaxial flexure at 0.5 mm/min. All fracture surfaces were analyzed using light microscopy and a select sample were examined using scanning electron microscopy. A simple two‐dimensional finite‐element model was used to evaluate the stress state at the core‐veneer interface of bend samples.

Results Failure loads were significantly higher for crowns having excess glass (Student's t test, P < .004). Weibull moduli were indistinguishable (m = 6.2) between crown groups, consistent with the microscopic impression that they shared a common failure mode. Microscopic evaluation of cross‐sectioned crowns showed core‐veneer interfaces with less porosity in the presence of excess infiltration glass. Failure loads for the disk groups were indistinguishable (Student's t test, P > .8). Scanning electron microscopic analysis of disk samples revealed that failures originated either at core‐veneer interfaces or at lower disk surfaces, consistent with the finite‐element analysis.

Conclusion Excess infiltration glass on the core surface will not degrade the strength of In‐Ceram structures. Central incisor crowns (as tested) were strengthened by excess infiltration glass, but disk samples (stressed differently) were not. Finite‐element results suggest that disk failure originates from three possible sources.
Using an Existing Orbital Prosthesis in the Construction of a New One
Authors: Polyzois Gregory L.
Published: March 2005

A procedure for fabrication of a new orbital prosthesis using an existing one and keeping its acceptable characteristics is described. The procedure saves time without depriving the patient of the existing prosthesis for a long period and can be applied in the remaking of other types of facial prostheses.
Factors Associated With Successful Denture Therapy
Authors: Diehl Roberta L. , Foerster Ulrich , Sposetti Venita J. , Dolan Teresa A.
Published: March 2005

Purpose

The purpose of this investigation was to evaluate complete denture patients at pretreatment and postinsertion, 6 months and 18 months after denture delivery in order to develop an explanatory model of successful denture therapy to better understand patient acceptance of complete dentures.

Materials and Methods

Sixty complete‐denture patients treated at a dental student clinic were followed through denture therapy and for 18 months thereafter. Subjects were examined and completed pretreatment questionnaires and posttreatment interviews. Three outcome measures of denture success were tested, and factors considered substantive in achieving a successful denture outcome were examined using multivariate analyses.

Results

At post‐insertion, 76.7% of subjects were satisfied with their dentures, 74.6% said their expectations were met, and 66.7% said they adjusted easily to their new dentures; reports at 6 and 18 months were similarly high. Logistic regression findings suggest that psychological and interpersonal factors are more important determinants of denture satisfaction than anatomic or clinical factors.

Conclusions

Subject characteristics including age, gender, race, income level, education, marital status, and maxillary and mandibular anatomy were not significantly associated with denture success as defined by the three outcome measures used in this study. Although these variables may represent important co‐factors in the patient's acceptance of dental services and may affect the way a patient perceives dental care outcomes, statistically significant relationships were not found within our sample. Psychosocial variables, such as pretreatment expectations, satisfaction with the dental care received, and mental health showed a stronger relationship to a successful outcome.
Marginal Fit of Electroformed Ceramometal Crowns
Authors: Holmes J. Robert , Pilcher Elizabeth S. , Rivers James A. , Stewart R. McQuay
Published: March 2005

Purpose

A method of fabricating ceramometal crowns using gold copings produced by an electroforming process has been described, which purportedly results in restorations exhibiting an excellent marginal fit. This study compares the fit of electroformed ceramometal crowns with ceramometal crowns fabricated using conventional lost wax casting techniques.

Materials and Methods

Electroformed and conventional ceramometal crowns were fabricated for prepared extracted teeth. Specimens were cemented, embedded in acrylic resin, sectioned, polished, photographed, and measured to compare marginal fit.

Results

Marginal fit of electroformed ceramometal crowns was superior to the fit of ceramometal crowns fabricated using conventional casting techniques. The difference was statistically significant at a P = .05 level.

Conclusions

Crowns utilizing copings fabricated by electroforming methods appear to have a fit superior to conventional ceramometal crowns fabricated using copings made by lost wax casting. The ease in laboratory electroforming techniques and the esthetic advantages of a gold‐colored coping can be capitalized on without concerns of a poorer fit.
Short‐Term Results of IPS‐Empress Inlays and Onlays
Authors: Studer Stephan , Lehner Christian , Brodbeck Urs , Schärer Peter
Published: March 2005

Purpose A leucite‐reinforced, glass‐ceramic material was recently introduced for clinical use. In this clinical trial, IPS‐Empress inlays and onlays were evaluated using the modified United States Public Health Service (USPHS) criteria.

Materials and Methods The teeth of 36 patients were restored with 105 posterior inlays and 25 onlays, fabricated by an indirect technique. After etching the restorations with hydrofluoric acid, they were silanized and luted using composite cements. The restorations were evaluated visually, clinically with a mirror and probe, and by bitewing radiographs and clinical photographs, using modified USPHS criteria. Restorations having neither charlie nor delta criteria were defined as successful, and their survival rate was calculated according to Kaplan‐Meier analysis.

Results The mean observation period for the 130 restorations was 23.4 ± 6.1 months. After 2 years, 127 restorations were successful with an estimated survival rate of 97.5%. Three restorations failed because of fractures. The esthetic results were excellent.

Conclusions The initial clinical results of this esthetic restorative material are encouraging. However, because of fatigue phenomena for all ceramic materials, a longer observation period is needed to provide a definitive prognosis of the long‐term clinical behavior.
A Rationale For Not Connecting Implants to Natural Teeth
Authors: Chee Winston W. L. , Cho George C.
Published: March 2005

When restoring partially edentulous arches with implants, there are some practitioners who believe it is occasionally beneficial to connect implants to natural teeth. This connection is performed to gain shared support from the natural tooth and implant, prevent rotation of the restoration, or sometimes merely to retain the natural tooth. A discussion and review of the literature concerning this connection is presented, and a patient treatment is shown to illustrate potential complications.
The Effects of Custom Tray Material on the Accuracy of Master Casts
Authors: Martinez Luis J. , von Fraunhofer J. A.
Published: March 2005

Purpose The accuracy of master cast reproduction by a polyvinylsiloxane impression material using two visible‐light‐curing resin and an autopolymerizing polymethyl methacrylate resin custom tray materials was investigated.

Materials and Methods Custom trays were fabricated from a master cast that had three index points marked on both the inner and outer vestibules. Impressions were made of the master cast using Extrude and then poured in Die Keen Green stone. The distances between the reproduced index points were measured to ±0.01 mm with a traveling microscope and the algebraic norms calculated for each tray material.

Results No differences (p > .05) were found in the dimensions of the inner index points, while the separations of the outer index points indicated that there were differences in the accuracy of reproduction (p > .01) by the three tray materials. The index points reproduced on the casts, compared with the master cast, were closer together for the Triad Blue trays than for the TruTray and Ontray impression trays.

Conclusions All three tray materials produced acceptable casts, but the greatest accuracy was achieved with TruTray, followed by Ontray. Triad Blue produced casts that were slightly smaller than the master. In practice, the small measured differences in cast dimensions may not have clinical significance.
An Alternative Technique for an Accurate Implant‐Retained Prosthesis Impression
Authors: Obeid Youssef E. , Driscoll Carl F. , Prestipino Vincent J.
Published: March 2005

A technique is described to help ensure the accurate reproduction of rigid implant components and the edentulous soft tissue. Splinted implant impression copings are luted together with resin to a specially designed custom tray.
Comparison of Sectioning Rates Among Carbide and Diamond Burs Using Three Casting Alloys
Authors: Siegel Sharon Crane , von Fraunhofer Joseph Anthony
Published: March 2005

Purpose

This study compared the sectioning rates of commercially available high noble, noble, and base metal casting alloys using two new cross‐cut tungsten carbides specifically manufactured for alloy sectioning and two medium grit diamond burs.

Materials and Methods

Rectangular bars cast from a base metal alloy (Ni‐Cr‐Mo‐Be), a noble alloy (Pd‐Cu‐Au), and a high noble alloy (Au‐Ag‐Cu‐Pd) were sectioned under controlled conditions. Two types of cross‐cut tungsten carbide and two types of medium grit diamond burs were tested using a high‐speed handpiece under a coolant flow rate of 20 mL/min and an applied load at the bur tip of 0.9 N (91.5 g). Three 4‐mm cuts were made through the alloy specimens using six burs of each type. The time required for Cuts 1, 2, and 3 was recorded, and sectioning rates in millimeters per minute were calculated as a relative measure of cutting efficiency. For each alloy, the total time required for the three cuts was analyzed using one‐way analysis of variance (one‐way ANOVA) and Scheffé tests (α= 0.05) to determine differences in sectioning rate among bur types.

Results

In general, mean sectioning rate for Cut 1 through Cut 3 decreased with longer use of the bur. Regarding total sectioning times, the carbide burs sectioned the base metal alloy significantly faster (P < .001) than the diamond burs. However, diamond burs sectioned the high noble alloy significantly faster (P < .001) than the carbide burs. Diamond burs also sectioned the noble alloy more quickly than the carbide burs, but the difference was not statistically significant.

Conclusions

The cross‐cut tungsten carbide burs should be used to section the base metal alloy but the medium grit diamond burs should be used to section the high noble alloy.
Fabrication of Complete Denture Bases Reinforced with Polyethylene Woven Fabric
Authors: Cheng Y. Y. , Chow T. W.
Published: March 2005

Incorporation of 5 layers of woven, high‐modulus polyethylene fiber into acrylic resin denture bases produces substantial improvements in mechanical properties and dimensional changes. A modified split‐pack technique has been developed using conventional dental‐laboratory compression molding to accommodate multiple layers of woven fabric in complete denture bases. A recess formed in the resin by a spacer allows the reinforcement to be embedded in the denture base without exposing the fibers. Embedded fibers do not compromise the esthetics of complete dentures.
Treatment of myocardial dysfunction and pulmonary oedema in an infant chimpanzee
Authors: Robel‐Tillig Eva , Eulenberger Klaus , Knüpfer Matthias , Junhold Jörg , Vogtmann Christoph , Kiess Wieland
Published: March 2005

Abstract:  The care of any critically ill infant requires special technical equipment for monitoring of cardiac and pulmonary functions including mechanical ventilators and blood gas analysers. The present paper describes the treatment of myocardial dysfunction and pulmonary distress, complicated by severe brain oedema in an infant chimpanzee admitted to an intensive care unit in the Department of Neonatology of the Children's Hospital of the University of Leipzig. The condition of the chimpanzee was diagnosed and monitored by standard clinical tooös including radiography, echocardiography, cerebral Doppler sonography and laboratory parameters. The chimpanzee was treated in close cooperation between veterinarians and paediatricians.
Metal Binding Ability of Metallothionein‐3 Expressed in Escherichia coli
Authors: Toriumi Shigeru , Saito Takeshi , Hosokawa Toshiyuki , Takahashi Yasumitsu , Numata Takuya , Kurasaki Masaaki
Published: March 2005

Abstract: Metallothionein‐3/growth inhibitory factor is a brain‐specific member of the metallothionein gene family, and impairs the survival and neurite formation of cultured neurons. Metallothionein‐3 can bind heavy metals such as Zn, Cu, or Cd almost in the same way as other metallothionein family. However, its biological function as growth inhibitory factor apparently distinguishes metallothionein‐3 from other metallothioneins. To better understanding of the relationship between the growth inhibitory activity of metallothionein‐3 and metals bound to metallothionein‐3, the metal‐binding ability of metallothionein‐3 was analyzed in comparison with those of metallothionein‐1 and ‐2. The metal‐binding ability of metallothionein‐3 was evaluated by pH titration and 5‐5′ dithiobis (2‐nitrobenzoic) acid (DTNB) analysis as compared with those of the other metallothioneins. The affinity of metal ions for metallothionein‐3 was indicated as follows, Cu>Cd>Zn, same as metallothionein‐1 and ‐2. However, the affinity of metallothionein‐3 to Cu was much higher than that of metallothionein‐1 and ‐2. The strong affinity to Cu of metallothionein‐3 might be related to its growth inhibitory activity.
HISPANIC AND NON‐HISPANIC RESPONSES TO CONCEPTS FOR FOUR FOODS
Authors: MOSKOWITZ HOWARD , ITTY BARBARA , KATZ RACHEL , MAIER ANDREA , BECKLEY JACKIE , FLORES LAURENT
Published: March 2005

Hispanics and non‐Hispanics Americans participated in four sets of studies dealing with health‐oriented foods, with the goal to identify how they respond to food categories relevant in any cuisine. Each study comprised a conjoint analysis using 36 elements followed by a self‐profiling questionnaire to learn more about Hispanic and non‐Hispanic food responses to concepts for four different product categories (morning bread, bottled water, healthful salad dressing and popcorn as a snack). The study identified patterns of preference of marketing statements in the areas of health information, sensory characteristics, emotional benefits and endorsements. Conjoint utility values generated by both Hispanics and non‐Hispanic respondents correlated highly, suggesting that their food attitudes are quite similar for“non‐signature”products despite the differences in their original cuisines.
PERFORMANCE COMPARISON BETWEEN TRAINED ASSESSORS AND WINE EXPERTS USING SPECIFIC SENSORY ATTRIBUTES
Authors: ZAMORA MARÍA CLARA , GUIRAO MIGUELINA
Published: March 2005

The profile of nine samples of Chardonnay wines was used to compare the performance of an expert panel and a trained descriptive panel using a common sensory terminology. Each panel (expert and trained) consisted of eight members, and the descriptors used by both groups were generated by the trained assessors. Thirteen out of 17 attributes evaluated turned out significant for wine discrimination among experts, and seven out of 17 for trained subjects. The trained panel reached a higher level of consensus, while the experts were more discriminative among attributes. The principal components analysis (PCA) corresponding to the expert group explained 88.68% of the total variance among the samples of the first two components. A third component was needed for the group of trained assessors (87.66% variance). The PCA showed the same wine grouping for both panels, indicating that differences were perceived in a similar way, despite that the sensory dimensions of these differences was not the same in all the cases.
Study of SARS Transmission Via Liquid Droplets in Air
Authors: Wang B. , Zhang A. , Sun J. L. , Liu H. , Hu J. , Xu L. X.
Published: March 2005

Microscale liquid droplets could act as the SARS carriers in air when released from an infected person through breathing, coughing, or sneezing. In this study, a dynamic model has been built to quantitatively investigate the effect of the relative humidity on the transport of liquid droplets in air using coupled mass transfer and momentum equations. Under higher relative humidity, the exhaled liquid droplets evaporate slowly. Larger droplets fall faster, which could reduce the probability of the droplets inhalation. This may be one of the most important factors that influence the SARS transmission in air.