bluuebunny/crossref_metadata_2025 huggingface dataset:
CORRECTLY MEASURING REAL VALUE ADDED
Authors: Cassing Shirley
Published: March 2005

This paper examines issues involved in calculating a value added index in order to measure real value added at the industry level. Three methods of calculating real value added are considered; the Laspeyres double‐deflation method recommended by the United Nations System of Nation Accounts, the commonly used single‐deflation method, and the double‐deflation Divisia method. Actual data are employed to clarify and illustrate the issues involved, and the paper concludes with a recommendation for an appropriate index to use when calculating industry real value added.
MISUSE AND USE OF NATIONAL ACCOUNTS AS A WELFARE INDICATOR: SELECTED ANALYTICAL AND MEASUREMENT ISSUES
Authors: Mamalakis Markos J.
Published: March 2005

Few economic relationships have been as scrutinized as that between SNA measures of national product, investment and consumption, and welfare. The present paper contrasts SNA economic production and welfare to total production and welfare within the Walrasian framework of usefulness and costliness. An evaluation of deductions and additions to the SNA made by Nordhaus‐Tobin, Zolotas, Richard and Nancy Ruggles, Kendrick, Eisner and Jorgenson‐Fraumeni, in their research on extended product and income accounts and improved indicators of welfare reveals numerous unresolved analytical and measurement issues; and reaffirms the usefulness of the SNA as a fundamental, initial, welfare indicator.
NONCASH INCOME, EQUIVALENCE SCALES, AND THE MEASUREMENT OF ECONOMIC WELL‐BEING
Authors: Radner Daniel B.
Published: March 2005

Little attention has been paid to the importance of consistency between the specifications of the income and the equivalence scales used in measuring economic well‐being when noncash income is included in the definition of income. This article finds that inconsistency between the income and needs sides of a comparison can be important when some types of noncash income are included. An upward bias in the measured economic status of the aged when Medicare is included in income and an ordinary equivalence scale is used is presented as an example of the important effects of this consistency problem.
IMPACT OF GROWTH AND DISTRIBUTION ON POVERTY IN MADAGASCAR
Authors: Essama‐Nssah B.
Published: March 2005

Poverty in Madagascar has increased between 1962 and 1980 both in the rural and urban areas based on a comparison of some poverty measures, but decreased based on others. However, it remains predominantly a rural phenomenon. Distributional inequality is the major determinant of the variation in rural poverty, while the changes in urban poverty are due to the lack of economic growth. Thus, the urban bias introduced in government policies in the mid‐1970s was not justifiable on strictly poverty‐reduction grounds. A reduction of sectoral disparities would have led to a significant reduction of aggregate poverty.
LIFETIME INEQUALITY AND TAX PROGRESSIVITY WITH ALTERNATIVE INCOME CONCEPTS
Authors: Creedy John
Published: March 2005

The increased availability of cohort data and use of dynamic microsimulation models means that more attention is now being paid to longer term income concepts. Results are usually reported for only one income concept and a limited number of summary measures, and it is not clear whether results are influenced by the income concept used. This paper uses simulation methods to compare different approaches. For this purpose a very simple lifecycle earnings model was used to generate profiles of pre‐tax incomes. Many comparisons were made using a flexible tax structure and four alternative income concepts. It was found that there was a substantial amount of agreement among the alternative concepts in making pairwise comparisons, with tentative support for the use of present values.
DIVERGENT INEQUALITIES: THEORY AND EMPIRICAL RESULTS
Authors: Wolfson Michael C.
Published: March 2005

Widely used summary measures of inequality or the idea of the “disappearing middle class” are potentially misleading. Divergences between evidence cited and conclusions drawn include failing to distinguish between the concepts of inequality and polarization, and using scalar “inequality” measures which are not consistent with rankings based on Lorenz curves. In addition, inappropriate claims about trends in inequality can arise from focusing on only a sub‐population such as full‐time male workers, and failing to account for sampling variability. These divergences are illustrated using Canadian data on labour incomes over the 1967 to 1994 period.
ACCOUNTING FOR EXHAUSTIBLE RESOURCES IN THE CANADIAN SYSTEM OF NATIONAL ACCOUNTS: FLOWS, STOCKS AND PRODUCTIVITY MEASURES
Authors: Diaz Aldo , Harchaoui Tarek M.
Published: March 2005

The paper shows that the Canadian System of National Accounts includes exhaustible resources but treats them as if they were produced goods. Thus, the claim that conventional accounts ignore the contribution of exhaustible natural resources is partly true. To fully account for exhaustible resources, we present an alternative national accounting framework that incorporates natural resource flows and stocks. The framework modifies the measure of the net domestic product by a factor that differs from the Hartwick‐Solow‐Weitzman rule and leads to different estimates of GDP, national wealth, and productivity growth. An application to the Canadian oil and gas industry shows order‐of‐magnitude effects.
DOES SAMPLE DESIGN MATTER FOR POVERTY RATE COMPARISONS?
Authors: Howes Stephen , Lanjouw Jean Olson
Published: March 2005

Poverty comparisons—an increasingly important starting‐point for welfare policy analysis‐are almost always based on household surveys. Therefore they require that one be able to distinguish underlying differences in the populations being compared from sampling variation: standard errors must be calculated. This has typically been done assuming that the household surveys are simple random samples. However, household surveys are more complex than this. We show that taking into account sampling design has a major effect on estimated standard errors for well‐known poverty measures. In our samples they increase by around one‐half. We also show that making only a partial correction for sample design (taking into account clustering, but not stratification, whether explicit or implicit) can be as misleading as not taking any account of sampling design at all.
DEFLATION OF INPUT‐OUTPUT TABLES FROM THE USER'S POINT OF VIEW: A HEURISTIC APPROACH
Authors: Dietzenbacher Erik , Hoen Alex R.
Published: March 2005

This paper considers the problem of deflating an input‐output table from the viewpoint of the user. In many practical cases certain margins of this table are readily available in constant prices, whereas the entire table is not. This reduces the problem to estimating the matrix of sectoral intermediate deliveries in constant prices. The traditional approach for this purpose is based on the double deflation method. Since double deflation is sensitive to aggregation, however, it typically does not provide correct answers. Therefore, a heuristic approach is proposed as an alternative. It is based on the biproportional projection method. An empirical evaluation indicates that the heuristic approach clearly performs better.
LABOR INCOME INDICES DESIGNED FOR USE IN CONTRACTS PROMOTING INCOME RISK MANAGEMENT
Authors: Shiller Robert J. , Schneider Ryan
Published: March 2005

We propose that labor income indices be used to define settlements in many contracts, such as labor contracts, indexed bonds, or income securities. We discuss the issues in producing labor income indices for such uses, and develop prototype indices using US. data from the Panel Study of Income Dynamics (PSID). People are grouped by a clustering algorithm based on an estimated transition matrix between jobs, by education level, and by skill category. The groupings are defined so that few people move between them. For each grouping we generate a labor income index (1968–87) using a hedonic repeated‐measures regression method. The indices show substantial variability through time, confirming the potential importance of the use of such indices in contracts. There is also substantial variability across groupings, as for example between the agriculture/labor grouping and other groupings, confirming the importance of using the grouping indices rather than aggregate indices in contracts.
WEALTH ACCUMULATION OF CANADIAN AND FOREIGN‐BORN HOUSEHOLDS IN CANADA
Authors: Shamsuddin Abul F. M. , DeVoretz Don J.
Published: March 2005

This study focuses on the role of foreign‐born households in Canada's asset market. An empirical analysis of wealth accumulation is conducted for a large sample of Canadian households circa 1977–84. This study period reflects a change in Canada's immigration policy which resulted in immigration Rows switching from Europe to Asia. A life‐cycle framework is used to examine wealth accumulation behaviour of the foreign‐born vis‐à‐vis Canadian‐born households. The empirical results confirm the existence of an inverted ‘U’‐shaped wealth‐age profile for both Canadian and immigrant households. However, the 1977 results show that the rate of wealth accumulation is higher for the immigrant household than the Canadian‐born household in pre‐retirement years, while the 1984 results reveal the opposite. After retirement, the rate of wealth dissipation is slower for Canadians than for foreign‐born households. Only the 1984 results indicate that public social security wealth displaces household savings for both the Canadian‐born and the foreign‐born by a small amount. Finally, an immigrant household exhibits a stronger transfer motive within a family than a Canadian‐born household regardless of year tested.
EARNINGS MOBILITY: AN INTERNATIONAL COMPARISON OF ITALY AND FRANCE
Authors: Bigard A. , Guillotin Y. , Lucifora C.
Published: March 2005

In this study we consider two panels of wage‐earners, from 1974 to 1988, for Italy and France respectively. The international perspective and the availability of micro‐data are particularly interesting for they allow us to address individual characteristics as well as national specificities. In the empirical analysis a partitioning of the earnings distribution by deciles is used and the overall hierarchical mobility of individuals is investigated. Transition matrices are computed in order to compare wage formation and mobility processes across countries, in the period under investigation. A rich battery of mobility indices is presented and the relations between them are studied.

The paper addresses several different issues and compares the results across countries. First, the evolution of earnings and the relative wage profiles are compared across countries. Second, the heterogeneity issue is addressed and some structural characteristics of the sample are studied, namely: cohort and gender differences in earnings.
COHABITATION AND THE MEASUREMENT OF CHILD POVERTY
Authors: Carlson Marcia , Danziger Sheldon
Published: March 2005

We use 1990 U.S. Census of Population data to calculate what poverty rates would have been if cohabitors were treated in the same manner as married couples. We find that the official treatment of cohabiting partners as separate family units overstated the extent of poverty in 1989 among all children by about three percent. Only about 11 percent of the observed rise in child poverty between 1969 and 1989 would be eliminated if the Census Bureau made this change in its definition of the family. We estimate a logistic regression model of the likelihood that poor, cohabiting families with children would be reclassified as non‐poor if the cohabitor's income were included in family income.
NET ACCUMULATION OF TIMBER RESOURCES
Authors: Vincent Jeffrey R.
Published: March 2005

National accounting issues related to forest resources have attracted much attention recently. The net‐depletion method, the most popular method for estimating aggregate changes in the value of timber stocks, tends to overstate both the depreciation of mature forests due to harvests and the appreciation of immature forests due to growth. Alternative, correct methods, which I term the net‐price and El Serafy variations, can be derived from an asset valuation model that takes forest age into account. An empirical example indicates that estimates from the net‐depletion method can deviate from actual values by up to 40 percent for some age classes.
INTEREST AND INFLATION ACCOUNTING
Authors: Vanoli Abdré
Published: March 2005

This paper analyses the treatments proposed by Chapter XIX (Annex B) of the 1993 SNA and the manual Inflation Accounting published by the OECD (Peter Hill) as alternatives to the traditional recording of nominal interest. Real interest and interest prime (annex B) are relevant for different purposes. Their amounts are not the same to the extent that actual compensation and full required compensation for inflation differ. The recording of negative real interest is not compatible with the exclusion of holding gains/losses from the SNA current accounts. The accounting treatments in Inflation Accounting (capital transfers, additional lending/borrowing, no nominal holding gains/losses) and Annex B (nominal holding gains/losses, no capital transfers, no new lending/borrowing) are contrasted.
LABOR EARNINGS AND HOUSEHOLD INCOME MOBILITY IN REUNIFIED GERMANY: A COMPARISON OF THE EASTERN AND WESTERN STATES
Authors: Hauser Richard , Fabig Holger
Published: March 2005

Using data from the German Socio‐Economic Panel, we compare income mobility of persons from the eastern and western states of Germany between 1990 and 1995. We consider income mobility between consecutive years and between the first and the final year of this time period. We find that gross individual labor income mobility was much higher in the east than in the west during the first years after reunification, but that this difference has become much smaller until 1995. Changing to measures that reflect economic well‐being more accurately, we observe that gross equivalent labor income mobility and net equivalent income mobility initially were also much higher in the eastern states than in the western states, but converged over time as well. This convergence has been particularly strong for net equivalent income mobility, suggesting that the social protection system has greatly reduced mobility risks associated with the transformation process in the eastern states of Germany.
POLARIZATION BY SUB‐POPULATIONS IN SPAIN, 1973–91
Authors: Gradín Carlos
Published: March 2005

We use an extension of the Esteban and Ray (1994) approach to polarization in order to analyze the role of different household characteristics in the formation of groups in Spanish expenditure distribution, e.g. educational level, position in the labor market, and region. According to a first approach we assume that groups are determined by a characteristic that their members share, and we study which gives rise to a higher level of polarization. In a second approach we can also investigate which characteristics better explain an observed level of polarization, assuming that income proximity determines the group to which one belongs. In both cases we take into account the effect of social stratification on polarization.
Osteoporosis and Osseointegration of Implants
Authors: Baxter J. Crystal , Fattore LaDeanne
Published: March 2005

According to medical literature, osteoporosis and related bone pathologies are increasing in epidemic proportions. The exact etiology of the disease is unknown, but hormonal, dietary, and genetic factors all contribute to the related loss of bone density. In the disease process, bone loss occurs throughout the body. Research indicates that the mandible and maxilla are affected, and show oral manifestations. There is no scientific data to contraindicate the use of two‐step osseointegrated implants in osteoporotic individuals. The purpose of this article is to review the literature regarding osteoporosis and its relationship to oral bone loss.
The Relationship Between Preparation Convergence and Retention of Extracoronal Retainers
Authors: Wilson Aaron H. , Chan Daniel C. N.
Published: March 2005

Purpose

Although traditional ideal convergence (the sum of taper of the opposite sides) for crown proparation has been arbitrarily set at 4° to 10°, some believe absolute parallelism yields the highest retention. This study examined the relationship between the degree of convergence of a machined metal die and the retention of its casting.

Materials and Methods

The method used was that of cementing cast metal crowns onto full crown preparations on brass dies with varying convergence angles, and then recording the force required to remove the crowns from the dies in a vertical direction using a Tate‐Emery Testing Machine and Load Indicator.

Results

It was found that retention (ie, the force needed to remove the cemented castings from the die in their common long axis) increases from O° convergence to peak between 6° to 12° convergence. It also seems that a critical film thickness does exist for optimum retention, and that film thicknesses smaller than the critical thickness may be responsible for the phenomenon that we have observed and directly related to the convergence angle itself.

Conclusions

There seems to be experimental data supporting the use of traditionally taught convergence. Our study found that convergence angles between 6° and 12° seem to be optimum for tooth crown preparation when one plans to use zinc phosphate cement. Convergence angles of less than 6° may not be desirable even if they can be clinically achieved. The results of our study indicate that a relationship exists between the convergence angle and the critical cement thickness that is necessary to realize the maximum strength properties of zinc phosphate cement.
The Use of a Photoprotective Agent to Increase the Color Stability of a Tinted Extraoral Prosthetic Silicone
Authors: Bryant Arthur W. , Schaaf Norman G. , Casey David M.
Published: March 2005

Purpose

This study investigated the use of ultraviolet‐absorbing or photoprotective agents as a method of decreasing the color changes caused by ultraviolet radiation on an intrinsically tinted facial prosthetic material.

Materials and Methods

Silastic MDX 4‐4210 (Dow Corning Corp, Midland, MI) was the facial prosthetic material studied. It was intrinsically tinted with talc and nylon flock to approximate the color of skin. Three brands of commercially available sunscreens with sun protective factor (SPF) of 15 were placed on the surface of the cured silicone samples. The samples were rotated in an ultraviolet radiation chamber for 300 hours. A control group was placed in the dark for 300 hours. The second phase of the experiment had para‐aminobenzoic acid (PABA) added to the tinted silicone. All samples were measured with a spectrophotometer at the beginning and at the end of 300 hours, and a ΔE was obtained.

Results

None of the sunscreens provided any ultraviolet radiation protection to the silicone. The addition of PABA caused a significant color degradation of the silicone.

Conclusions: No photoprotective agent tested provided any significant level of ultraviolet radiation protection for silastic MDX 4‐4210.
Modalities of Treatment for the Combination Syndrome
Authors: Langer Yair , Laufer Ben‐Zion , Cardash Harold S.
Published: March 2005

A series of destructive changes occurring in the jaws of patients wearing a complete maxillary denture opposed by a mandibular distal extension removable partial denture have been described as the combination syndrome. However, the syndrome does not occur in all patients. Those patients who have not developed signs of the combination syndrome and whose mandibular anterior teeth are well preserved and not overerupted may be treated conservatively with a mandibular removable partial denture. A properly designed removable partial denture that distributes occlusal stresses over hard and soft tissues minimizes the risk of developing the combination syndrome. Nevertheless, the overdenture seems to provide a more predictable prognosis, especially for patients who already have the combination syndrome or whose mandibular anterior teeth are structurally or periodontally compromised or overerupted. The treatment modality is determined by the apparent potential of the patient to develop the combination syndrome and by the condition of the remaining mandibular anterior teeth.
A Comparison of Microwave and Dry‐Heat Curing Methods on the Bond Strength of Silicone Facial Materials Applied to Acrylic Resin
Authors: Polyzois Gregory L.
Published: March 2005

Purpose

This study compared two curing methods (microwave irradiation and dry heat) on the tensile bond strength of silicone facial materials to cured acrylic resin. The facial materials studied were Mollomed, Silskin II, MDX4‐4210, and A‐2186.

Materials and Methods

The samples were processed with microwaves for 13 minutes at 90 W plus 2 minutes at 500 W and dry heat for 3 hours at 100° C to cured acrylic resin. Facial materials 3‐mm thick were processed between two half‐dumbbells of acrylic resin. The bonding surfaces were treated with a primer. The samples were placed in tension until failure.

Results

The results showed that the bond strength was affected by the type of silicone material and not by the curing methods used.

Conclusions

Mollomed had the highest bond strength of all materials tested. MDX4‐4210 and A‐2186 showed the lowest, and Silskin II had intermediate bond strength. Microwave irradiation has the potential of saving time, energy, and resources during the fabrication of facial prostheses, but further laboratory studies and clinical trials are indicated.
The Institute of Medicine Study of Dental Education: Issues Affecting Prosthodontics
Authors: Diaz‐Arnold Ana M. , Langenwalter Eric M. , Andres Carl J. , Lloyd Patrick M. , Nimmo Arthur , Cronin Robert J.
Published: March 2005

In 1993, the National Academy of Sciences' Institute of Medicine (IOM) convened a committee to study dental education and to make recommendations regarding the future of dentistry. The study was prompted by educational and professional concerns: specifically, the number of dental school closures, the high cost of dental education, the size of the dental workforce, and the role of dentistry within medicine and the health care system. In January 1995, the IOM's Committee on the Future of Dental Education concluded “Dental Education at the Crossroads—Challenges and Change”, a 345‐page report that includes eight policy and strategic principles and presents 22 recommendations.1 The unabridged text of the strategic principles and recommendations is published at the beginning of this paper.

The IOM text notes impressive achievements in dentistry, and the recommendations form a foundation for the assessment of the many crucial issues that face dental education and dentistry today. The IOM report urges each dental school to review its curriculum and individually determine how best to fulfill its missions of education, research, and patient care. As dental education looks to the future, the practice of dentistry will be altered by social, economic, political, and technological developments as our consumers (students and patients) demand professional accountability and effectiveness.2 In the midst of this call for change, the specialty of prosthodontics is faced with many challenges and opportunities. This article is the response to a request from the American Dental Association (ADA) to address the IOM study on dental education as it affects the specialty and practice of prosthodontics. This article presents the position of the American College of Prosthodontists (ACP); however, some sections have been expanded to provide additional background information.
A Seminar/Case‐Based Approach to Teaching Removable Partial Dentures to Predoctoral Students
Authors: LaVere Arthur M. , Sarka Robert J. , Marcoft Keith R. , Smith Roland C. , Holloway Gerald W.
Published: March 2005

This article describes a seminar/case‐based, instructional model designed to simulate removable partial denture (RPD) problem‐solving and decision‐making processes encountered in third‐year clinic in dental school and in dental general practice. Groups of approximately 20 second‐year students (in the 3‐year program) meet in a series of six 1‐hour seminars during the first days of the course. Following the seminars, students complete an exercise on mouth preparation and multiple clasp and major connector designs on prototype casts. This is followed by survey‐design exercises on casts of dentitions representing six variations of RPD requirements. Instructors assist students during the practice phase of each class. Each 2‐hour practice session is followed by a 1‐hour practical examination. The last day of the course is devoted to a comprehensive final practical examination on both maxillary and mandibular casts, incorporating any of the design features previously studied.
The Effect of Eugenol‐Containing Temporary Cement on the Bond Strength of Two Resin Composite Core Materials to Dentin
Authors: Al Wazzan Khalid A. , Al Harbi Ali A. , Hammad Ihab A.
Published: March 2005

Purpose This study investigated the effect of eugenol‐containing temporary cement on the bond strength of two resin composite core materials (FluoroCore and Ti‐Core) to dentin.

Materials and Methods Dentin was exposed in three groups of extracted teeth (20 specimens each). In group one, dentin was covered with eugenol‐containing temporary cement; the second group was covered with eugenol‐free temporary cement; and the third group was left uncovered and served as a control group. All specimens were stored for 1 week at 37°C and 100% humidity. The dentin surfaces were cleaned and treated using the GLUMA adhesive system, followed by placement of composite core build‐ups. Debonding of the core material was accomplished using the Accuforce Elite test system.

Results There was a significant reduction in bond strength for the specimens covered with eugenol temporary cement (p < .0001), but no significant difference was found between the control group and the group treated with eugenol‐free temporary cement. Bond strength of the Ti‐Core material to dentin was significantly higher than that of FluoroCore (p < .0001).

Conclusion Pretreatment of the dentin with eugenol‐based temporary cement adversely affects the bond strength of resin composite core material to dentin.
Quality Assurance for the Laboratory Aspects of Prosthodontic Treatment
Authors: Maxson Barbara B. , Nimmo Arthur
Published: March 2005

Inconsistency in the product returned from the commercial dental laboratory led to the development of a formal quality assurance (QA) program at the University of Detroit Mercy School of Dentistry in 1994. The goal of the program was to improve the quality of prosthodontic laboratory submissions and the returned product, facilitate laboratory communications, and, ultimately, enhance the quality and timeliness of patient care. Each student submission is evaluated with a criterion‐referenced evaluation form. Deficiencies are communicated to the student, and the corrected submission is then sent to the laboratory. Three‐year remake data from the main clinic (QA site) and an extramural clinic (non‐QA site) demonstrate the effectiveness of the program. The major benefits are more efficient, cost‐effective patient care, as well as the provision of a model for the student to practice the skills needed for effective communication with the dental technician, upon graduation.
Crevicular Fluid Analysis Around Two Failing Dental Implants: A Clinical Report
Authors: Curtis Donald A. , Kao Richard , Plesh Octavia , Finzen Fredrick , Franz Larry
Published: March 2005

The criteria for monitoring tissue health around endosseous implants remain subjective. Disagreement about which clinical measures of peri‐implant health are of diagnostic value continues because of the complexity of the disease process and lack of validated measures of peri‐implant health. Crevicular fluid analysis of various inflammatory mediators has been investigated as a means of providing objective criteria of tissue health. In this clinical report, the crevicular fluid levels of interleukin‐1β (IL‐1β), an inflammatory cytokine, were used to provide an objective measure of the peri‐implant health and the effectiveness of treatment for a patient with two failing implants. The measurement of IL‐1β may be an important supplement to clinical findings in establishing a diagnosis of peri‐implantitis.
Replicating Soft Tissue Contours on Working Casts for Implant Restorations
Authors: Chee Winston W. L. , Cho George C. , Ha Seonho
Published: March 2005

Restoration of partially edentulous arches is often aided by the use of dental implants. When anterior edentulous spaces are restored, the clinician is challenged to provide an esthetic and functional restoration. The soft tissue that surrounds the implant restoration and the soft tissue at the base of the pontics are important factors in achieving an esthetic result. A technique is presented that will allow soft tissue morphology of both peri‐implant and pontic bearing soft tissue to be incorporated into the working cast utilizing a provisional restoration. This allows the fabrication of a restoration that will harmonize with the soft tissue form of the patient.
The Effect of a Carbonated Beverage on the Wear of Human Enamel and Dental Ceramics
Authors: Al‐Hiyasat Ahmad S. , Saunders William P. , Sharkey Scott W. , Smith George McR.
Published: March 2005

Purpose This study was performed to investigate the effect of a carbonated beverage on the wear of human enamel and three dental ceramics: a conventional porcelain (Vitadur Alpha), a hydrothermal low‐fusing ceramic (Duceram‐LFC), and a machinable ceramic (Vita Mark II).

Materials and Methods Tooth‐against‐ceramic specimens (10 per group) were tested in a wear machine under a load of 40N, at a rate of 80 cycles per minute, and for a total of 25,000 cycles. The test was performed in distilled water or with intermittent exposure to a carbonated beverage (Coca‐Cola). Wear was determined by measuring the height reduction of the tooth specimens and the depth of wear track in the ceramic specimens.

Results ANOVA revealed a significant difference among the groups for both enamel and ceramic wear (p < .001). When tested in water. Alpha porcelain caused significantly more enamel wear and also exhibited greater wear than Duceram‐LFC and Vita Mark II. However, with exposure to the carbonated beverage, the enamel wear produced by Duceram‐LFC did not differ significantly from that produced by Alpha porcelain, and Vita Mark II produced the least amount of enamel wear. Overall, exposure to the carbonated beverage significantly increased the enamel wear. The wear of Duceram‐LFC and Vita Mark II increased with exposure to the carbonated beverage.

Conclusions It was concluded that exposure to the carbonated beverage accelerated the enamel wear and decreased the wear resistance of Duceram‐LFC and Vita Mark II ceramics. Overall, Vita Mark II was shown to be the most resistant to wear and also significantly less abrasive than conventional Alpha porcelain.
A Pilot Study to Evaluate Different Palate Materials for Maxillary Complete Dentures with Xerostomic Patients
Authors: Hummel Susan K. , Marker Victoria A. , Buschang Peter , DeVengencie DDS James, MS
Published: March 2005

Purpose

The hypothesis tested in this pilot study was that materials used for the palatal region of a maxillary denture affect the comfort of the maxillary denture in xerostomic patients.

Materials and Methods

Xerostomic complete denture wearers were selected to test three different maxillary dentures that were made with different palatal materials. Each denture was worn for a period of 2 weeks. The Kapur Index was used to measure retention. The Oral Health Index Profile (OHIP) was used to determine the patient's perception of each denture after the 2‐week period. At the end of the study, the patients were asked to select which of the three dentures they would like as their primary denture.

Results

All participants chose the metal‐palate dentures, and 4 of 5 selected the titanium‐palate denture as their primary denture. Statistical analysis of the OHIP demonstrated that the metalpalate dentures were perceived as being more comfortable than the acrylic‐resin dentures.

Conclusion

This pilot study suggests that for xerostomic patients who have worn complete dentures, their selection of a metal‐palate denture as their primary prosthesis strongly suggests that these dentures have properties that make them more comfortable to the patient than acrylic dentures. Subjective patient measurements supported this conclusion that the metal‐palate dentures were preferable, while the evaluation method available to the clinician failed to discriminate among the prostheses.
Effective Taper Criterion for the Full Veneer Crown Preparation in Preclinical Prosthodontics
Authors: Smith Charles T. , Gary John J. , Conkin J. Elaine , Franks Hurby L.
Published: March 2005

Purpose

Effective taper criteria must define a realistic, measurable goal that the student can visualize and achieve. Six degrees is widely accepted as the taper criterion for the full veneer crown preparation. However, studies show the actual taper of most preparations to be greater than 12°. The purpose of this study was to determine whether 12° is an effective taper criterion for the full veneer crown preparation in preclinical prosthodontics instruction.

Materials and Methods

A group of 191 full veneer crown preparations with 6° as the taper criterion, and a group of 130 full veneer crown preparations with 12° as the taper criterion were evaluated. All preparations were accomplished by preclinical dental students working on typodonts under examination conditions.

Results

The overall mean taper for each group exceeded the targeted criterion. The overall mean taper for the 6° group was 14.490. When 12° was the criterion, the overall mean taper was 15.580. The t test results indicate significant differences (p < .0001) between the targeted criterion and the actual preparation mean taper in all samples except one: the faciolingual measurements in the 12° group. The faciolingual measurement of 12.920 was not statistically significantly different (.0542) from the targeted criterion of 12°.

Conclusion

The use of a 12° taper criterion did not result in preclinical students achieving the goal of a 12° taper. However, a 12° criterion is more realistic than a 6° criterion for full veneer crown preparations.
Fabrication of a Surgical Stent for Bilateral Tuberosity and Mandibular Alveolar Reduction
Authors: Markt Jeffery C.
Published: March 2005

A technique for constructing a single surgical stent to direct bilateral preprosthetic maxillary tuberosity reductions and mandibular alveolectomies is presented. The stent is fabricated using unaltered articulated definitive casts. The stent allows the oral surgeon to replicate the desired vertical dimension of occlusion for a thorough assessment of the sufficiency of the surgical revisions. The situation illustrated is unique, in that preoperatively, the patient's maxillary tuberosities were situated inferior and medial to their ipsilateral retromolar pads.
A review of spontaneous neoplasia in baboons (Papio spp.)
Authors: Cianciolo Rachel E. , Hubbard Gene B.
Published: March 2005

Abstract:  The baboon has become an increasingly important animal model and accurate information on baboon neoplasia is frequently required for biomedical research. To satisfy this demand, a complete literature search was carried out. Two hundred and four spontaneous neoplasms were found in published literature: 53 cases were male (26%), 76 were female (37%); sex was not reported in 75 cases (37%). Ages ranged from 3 months to 31 years (mean 14.1 years) in the 93 cases that reported them. Spontaneous neoplasms have been documented in Papio cynocephalus and Papio hamadryas as well as in most subspecies and hybrid combinations. The organ systems affected in descending order of number of neoplasms were hematopoietic (n = 53, 26%), alimentary (n = 52, 25%), urogenital (n = 35, 17%), integumentary (n = 26, 13%), endocrine (n = 14, 7%), nervous (n = 12, 5%), musculoskeletal (n = 4, 2%) and respiratory (n = 3, 1%). There were five miscellaneous neoplasms (2%) that could not be classified by system. Lymphosarcoma was the most common neoplasm (n = 51, 25%), and adenocarcinomas were second (n = 23, 11%), followed by squamous cell carcinomas (n = 10, 5%). Malignant cases numbered 114 (56%); 87 cases were (43%) benign. The malignancy of three cases (1%) was unreported.
Comparison of the effects of Percoll and PureSperm® on the common marmoset (Callithrix jacchus) semen
Authors: Hernández‐López L. , Umland N. , Mondragón‐Ceballos R. , Nayudu P.L.
Published: March 2005

Abstract:  Density gradient centrifugation is a widely used technique for the separation of motile from non‐motile sperm, for the removal of contaminating agents such as bacteria and viruses, and for the removal of seminal plasma or cryoprotectant. In the choice of a density gradient medium for a new species, it is important to perform toxicity tests. The present study was carried out to evaluate the potential toxic effects of two silica‐based density gradient products (Percoll and PureSperm), on the sperm of the common marmoset. We assessed two different batches of Percoll (polyvinylpyrrolidone (PVP)‐coated colloidal silica particles) and one of PureSperm (saline‐coated colloidal silica suspension) by means of a computer‐aided sperm analysis on semen collected by vibrostimulation. The results showed that although some of the sperm patterns of movement and viability changed significantly over time, and provide a first description of marmoset sperm motility changes under capacitating conditions, there was no significant difference in the sperm treated with Percoll or PureSperm in comparison with the control. We conclude that simple exposure to either of these products does not have a negative effect on viability or motility of marmoset sperm.
Traumatic injuries to the teeth in young individuals with cerebral palsy
Authors: Holan Gideon , Peretz Benjamin , Efrat Jacob , Shapira Yossi
Published: March 2005

Abstract –  The purpose of the study was to assess the characteristics of dental trauma in individuals with cerebral palsy (CP). The study group consisted of 68 individuals (36 boys and 32 girls) who visit daily a school dedicated for children with CP. Their age ranged between 7 and 21 years with a mean age of 12.6 years. The majority (74%) required a wheel chair for mobility, 13% used a walker and the others were able to walk with crutches or without aid. The parents were asked to complete a questionnaire regarding their child's age, gender, medical history, and history of dental trauma. The teeth were evaluated clinically for evidences of past injuries to the teeth, enamel defects in the permanent incisors, scars on the chin and size of overjet. Thirty‐nine individuals (57%) had signs of trauma to the permanent teeth. Sixty‐eight teeth, mostly the maxillary central incisors, were injured. Boys were slightly less affected than girls, 56% (20/36) and 59% (19/32), respectively. Fracture of enamel and dentine was the most common type of injury (62%). Scars on the chin were detected in 28% of the individuals but only one had fractures of the molar (primary) teeth. The overjet ranged between −3.0 and +14 mm but no correlation could be found between the size of the overjet and tendency to injure the teeth. Localized enamel defects were detected on the labial surface of 13 teeth in nine individuals, probably due to luxation injuries to the primary incisors. The prevalence of dental injuries in a group of individuals with CP was found to be much higher than that of healthy populations despite the fact that CP individuals do not take part in violent sport activities as healthy children do. This should alert caregivers to carry out a profound investigation of the events that result in dental injuries in disabled individuals and suggest methods to reduce this type of morbidity.
The Structure of (S)‐(–)‐4‐(2‐benzimidazolyl)‐4‐hydroxybutyric Acid Formed during Mammalian Metabolism of the Fungicide 2‐(2‐Furyl)benzimidazole
Authors: Frank Adrian , Norrestam Rolf
Published: March 2005

Abstract: During metabolism of the fungicide 2‐(2‐furyl)benzimidazole (FB) in mammals, an optically active compound, metabolite A, was isolated. This compound, a principal metabolite in the biological degradation of FB, was isolated from the urine of horse and dog. When studied by IR, NMR, MS, CD and electrophoretic techniques, the metabolite proved to be the zwitterionic form of (S)‐(–)‐4‐(2‐benzimidazolyl)‐4‐hydroxybutyric acid. The synthesized optical active compound was in every respect identical with metabolite A. The suggested structure has been completely verified by the current investigation of its crystal structure, based on single crystal diffraction data collected at the synchrotron MAX II in Lund, Sweden. In an earlier determination, a related compound, 3‐benzimidazolylpropionic acid (Ercan et al. 1996) was suggested to be non‐zwitterionic. The present studies have shown that the latter compound too is zwitterionic and that the conclusions presented were apparently based on some erroneously proposed hydrogen positions.
EFFECT OF COLD‐SET BINDERS: ALGINATES AND MICROBIAL TRANSGLUTAMINASE ON THE PHYSICAL PROPERTIES OF RESTRUCTURED SCALLOPS
Authors: SUKLIM KANNAPHPA , FLICK GEORGE J. , MARCY JOSEPH E. , EIGEL WILLIAM N. , HAUGH C. GENE , GRANATA L. ANKENMAN
Published: March 2005

Restructured scallops (Argopecten gibbys) were prepared with two cold‐set binders: 1% concentrations of alginate and microbial transglutaminase (MTG), with setting times of 2, 6, 9, 12, 18 and 24 h at 5C. Apparent modulus of elasticity, 5% secant modulus, 10% secant modulus and 20% secant modulus were used to evaluate the effect of setting times on the binding strength of restructured scallops. The binding strength as measured by the 5, 10 and 20% secant modulus was not significantly different (P > 0.05) in MTGase‐restructured scallops, but significantly different in alginate‐restructured scallops at 5 and 10% strain. Apparent modulus of elasticity showed significant differences in the binding strengths (P < 0.05) of restructured scallops prepared from both binders. The alginate gel restructured scallops achieved a binding strength of (158.7 kPa) in a 2‐h setting, while MTG‐restructured scallops reached a binding strength of (336.0 kPa) at a 24 h setting.
Finite Element Prediction of Proximal Femoral Fracture Patterns Under Different Loads
Authors: Go´mez-Benito M. J. , Garcı´a-Aznar J. M. , Doblare´ M.
Published: March 2005

The main purpose of this work is to discuss the ability of finite element analyses, together with an appropriate anisotropic fracture criterion, to predict the ultimate load and type of fracture in bones and more specifically in the proximal femur. We show here that the use of a three-dimensional anisotropic criterion provides better results than other well-known isotropic criteria. The criterion parameters and the anisotropic elastic properties were defined in terms of the bone tissue microstructure, quantified by the apparent density and the so-called “fabric tensor”, whose spatial distributions were obtained by means of an anisotropic remodeling model able to capture the main features of the internal structure of long bones. In order to check the validity of the results obtained, they have been compared with those of an experimental work that analyzes different types of fractures induced in the proximal femur by a static overload.
The Flow Field Downstream of an Oscillating Collapsed Tube
Authors: Bertram C. D. , Nugent A. H.
Published: March 2005

A two-component laser Doppler anemometer was used to determine the velocity of aqueous flow in the region from 0.25 to 2.5 diameters downstream of a collapsible tube while the tube was executing vigorous repetitive flow-induced oscillations. The Reynolds number for the time-averaged flow was 10,750. A simultaneous measurement of the pressure at the downstream end of the tube was used to align all the results in time at sixty locations in each of the two principal planes defined by the axes of collapse of the flexible tube upstream. The raw data of seed-particle velocity were used to create a periodic waveform for each measured velocity component at each location by least-squares fitting of a Fourier series. The results are presented as both velocity vectors and interpolated contours, for each of ten salient instants during the cycle of oscillation. In the plane of the collapse major axis, the dominant feature is the jet which emerges from each of the two tube lobes when it collapses, but transient retrograde flow is observed on both the central and lateral edges of this jet. In the orthogonal, minor-axis plane, the dominant feature is the retrograde flow, which during part of the cycle extends over the whole plane. All these features are essentially confined to the first 1.5 diameters of the rigid pipe downstream of the flexible tube. These data map the temporal and spatial extent of the highly three-dimensional reversing flow just downstream of an oscillating collapsed tube.
Optimal location of a service facility as a problem in basic mechanics
Authors: Chen Reuven
Published: March 2005

The economic problem of locating optimally a service facility in a two-dimensional Euclidean space is equivalent to a problem of equilibrium between forces in statics. A mechanical analog, suggested at the beginning of the century, as well as more modern numerical methods for the solution of the problem, are discussed. The multifacility problem, which is an extension to the original one, is also mentioned. Cases in which the cost involved is nonlinearly dependent on the Euclidean distance are briefly referred to.
Inferences from considering the twin paradox
Authors: Apfel Robert E.
Published: March 2005

If the twin paradox in the theory of special relativity is approached in a manner similar to Darwin [Nature 180, 976 (1957)], one can derive the explicit relativistic Doppler factor, f(β)=[(1∓β)/(1±β)]1/2, where the β≡(velocity of ship)/(velocity of light). The assumptions in deriving this expression are (1) f(β)f(−β)=1, and (2) if f(β) is used for approaching objects, then f(−β) is used for receding ones.
Bound states in the field of several noncollapsing inverse square potentials
Authors: Berezin Alexander A.
Published: March 2005

Depending on the value of β, a single attractive inverse square potential (−β/r2) has either no discrete bound states at all (if β< 1/8 atomic units), or has a discrete spectrum with infinitely low eigenvalues (if β> 1/8 ). The latter case is usually interpreted as the collapse of the particle towards the center. Here we consider the problem of several ‘‘noncollapsing’’ inverse square potentials, none of which separately have a discrete spectrum. We give a simple demonstration that such spatial superposition provides an intermediate case when the discrete level(s) exists and yet there is no collapse of the particle to the center. The ground state with the finite binding energy continues to exist even if the separation between individual potential wells increases indefinitely.
Reduced mass in an accelerated frame
Authors: Stephas Paul
Published: March 2005

It is demonstrated that the reduced-mass equation of motion for the two-body problem is in an accelerated frame whose origin is at one of the two particles. This accelerated-frame formalism is contrasted by an inertial-frame formalism.
Simple pendulum approximation
Authors: Ganley W. P.
Published: March 2005

The function [Fθ/sin (Fθ)]1/2 with F equal to approximately (3)1/2/2 is a close fit to the relative period of a simple pendulum as a function of amplitude. The fit is better than 5% up to 160°, and for 0°–100° the fit is better than ±0.001. Moreover, it can be derived without calculus.