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Biomedical subjects

A J Plasschaert

Publications and source records attributed to A J Plasschaert.

At least 19 recordsLinked to original sources

[Caries profunda: current views and treatment concepts].

Current insight of the caries process demands new, more selective and less invasive techniques and methods for excavation. Nowadays the biological aspects of teeth and pulp tissue in reaction to caries need to be respected and even used. The general practitioner is confronted with a wide range of new techniques and methods and needs to choose the best suitable. The purpose of this article is to inform the general practitioner about the current views concerning treatment of caries profunda and the different treatment concepts. Thereby the authors hope to assist the general practitioner in their choice for the proper treatment.

Dental Caries↗

Substance use among Dutch dental students.

OBJECTIVES: The objectives were to assess the prevalence of substance use among Dutch dental students and to determine their attitudes about substance use and its consequences. METHODS: In association with a national study of drug use among US dental students, a questionnaire was translated from English into Dutch and administered to dental students at two dental schools in The Netherlands. Students received an anonymous 115-item questionnaire in the fall of 1996. RESULTS: Alcohol was the students' drug of choice for lifetime (95%), past year (94%) and past month (88%) use. No significant correlations were found between alcohol use and gender, schools, and years in dental education. In the past month, 58% of students reported drinking on 5 or more days; 53% had 5 or more drinks on the same occasion, 20% had 5 or more drinks on the same occasion on 5 or more days; and 17% reported getting drunk at least monthly. Prevalence rates for past month use of tobacco was 24% and marijuana, 4%. Male students smoked twice as much as females, with significant differences found for all three periods of use (X2>19.00, P<0.01). When asked whether their schools offered policies and education programs on alcohol and other drugs, 52% of students reported that these were not available. CONCLUSIONS: Dental schools should develop effective programmes to educate students about responsible use of alcohol and other licit and illicit drugs. Schools should also inform students about their susceptibilities to substance abuse and dependency.

Adult↗

Effect of composite resin placement techniques on the microleakage of two self-etching dentin-bonding agents.

PURPOSE: To evaluate microleakage of Class V resin-based composites (RBC) bonded with two self-etching dentin adhesive systems. Class V cavities were restored with either one or three increments of RBC to determine whether the restorative method affected microleakage. MATERIALS AND METHODS: 60 extracted human premolars and molars were randomly assigned to 6 groups for bonding with Clearfil Liner Bond 2V or Etch & Prime 3.0 or Prime & Bond NT. The latter, using a total-etch technique, was used as a control. Cavities were cut in both the buccal and lingual surfaces. Half of each preparation was in enamel and half was in cementum/dentin. The teeth were thermocycled and the restorations examined microscopically for leakage using Procion Brilliant Red as a marker. SEM microphotographs were prepared from dye-labeled and non dye-labeled areas to illustrate the micromorphology of the systems. RESULTS: None of the groups showed microleakage at the enamel margins. All groups showed microleakage at the gingival margins. At the gingival margin, there was no significant difference between the groups irrespective of the bonding material (Kruskal-Wallis: ANOVA P=0.2113). No significant difference was observed with each material when the bulk filling (one increment) technique was compared with the three-increment technique. SEM showed that the self-etching materials produced a shallower depth of etch, and a less abundant resin tag complex than the material using a separate phosphoric acid gel. In dye-labeled areas, debonding was predominantly cohesive in resin. CLINICAL SIGNIFICANCE: Gingival margin microleakage is not prevented by either restoring cavities with self-etching materials of the control using a total-etch technique.

Acid Etching, Dental↗

Microleakage of tetric ceram/excite and Ariston pHc/Ariston liner.

PURPOSE: To investigate the microleakage associated with a hybrid resin-based composite, Tetric Ceram, bonded with the single component dentin bonding agent Excite and Ariston pHc bonded with Ariston Liner. Ariston pHc bonded with Excite and Tetric Ceram bonded with Prime and Bond NT were used as controls. MATERIALS AND METHODS: Twenty-four extracted human premolars and molars were randomly assigned to four groups. Group 1: cavities were bonded with Excite and filled with Tetric Ceram. Group 2: cavities were bonded with Ariston Liner and filled with Ariston pHc. Group 3, control: cavities were bonded with Prime & Bond NT and filled with Tetric Ceram. Group 4, control: cavities were bonded Excite and filled with Ariston pHc. Cavities were cut in both the buccal and lingual surfaces. Half of each preparation was in enamel and the other was in cementum/dentin. The teeth were thermocycled at 15 degrees C for 2 s, 35 degrees C for 28 s and 45 degrees C for 2 s for 5,000 cycles after which the restorations were examined microscopically for leakage using procion brilliant red as a marker. SEM microphotographs were prepared from dye-labeled and non dye-labeled areas to illustrate the micromorphology of the systems. RESULTS: None of the groups showed microleakage at the enamel margins. All groups showed microleakage at the gingival margins. At the gingival margin there was a significant difference between the groups (Kruskal-Wallis ANOVA, P= 0.1111.). Ariston pHc/Ariston Liner showed significantly lower microleakage scores than the other groups (Dunn's Multiple Comparison test). SEM showed that in non-dye labeled areas, Ariston pHc/Ariston Liner was in close apposition to the deeper dental tissues. The "total etch" technique resulted in a zone of demineralization. Debonding occurred at or near the top of the hybrid layer in >95% of specimens.

Acid Etching, Dental↗

Marginal leakage of filled dentin adhesives used with wet and dry bonding techniques.

PURPOSE: To evaluate the effect of wet and dry bonding on microleakage of Class V restorations bonded with three filled bonding agents. MATERIALS AND METHODS: Sixty extracted human premolar and molar teeth were randomly assigned to five groups for bonding with OptiBond Solo, PermaQuick PQI, Prime & Bond NT (one coat), Prime & Bond NT (two coats) and Prime & Bond 2.1, as a control material. Cavities were cut in both the buccal and lingual surfaces. Half of each preparation was in enamel and the other was in cementum/dentin. The cavities were restored with resin-based composite after the application of dentin bonding agents using a wet and dry technique for each material. The teeth were stored in distilled water for 6 days at 37 degrees C, thermocycled, and the restorations examined microscopically for leakage using Procion Brilliant Red as a marker. RESULTS: All groups showed microleakage at both the enamel and dentin margins. At the gingival margin, there was a significant difference between the groups for wet bonding (P = 0.0349) but not for dry bonding (P = 0.9983) (Kruskal-Wallis test). There was no significant difference between the groups at the enamel margin (wet bonding: P = 0.9999, dry-bonding: P = 0.9304) (Kruskal-Wallis test). The wet-bonding technique was compared with the dry-bonding technique for each material at both the gingival and enamel margins and no significant differences were observed (in all cases P > 0.5) (Mann-Whitney U-test).

Analysis of Variance↗

[Dentist's opinion about their dental education in Nijmegen, the Netherlands from 1990-1997].

A questionnaire was sent to 328 dentists graduated from the University of Nijmegen in the period 1990-1998, to ask their opinion concerning the way they were prepared by dental education for their professional career. Comparison with similar data from Amsterdam Academic Centre for Dentistry has been carried out. The results show unanimity among graduates that they have been adequately prepared for the requirements in general dental practice as far as knowledge is concerned related to cariology, periodontology, crown and bridgework and dental radiology. They also have a positive assessment regarding other dental cognitive domains, except implantology. There is positive unanimity regarding their skills in various clinical areas. Shortcomings in dental education have been experienced in practice management and infection prevention, treatment of medically compromised patients, treatment of anxious patients and handicapped patients. Almost all responders have the opinion that they gained enough experience throughout their dental education to be competent to start their dental career independently. In general the Nijmegen graduates have a positive opinion concerning their dental education, although preparation for professional life could be strengthened in some specific areas. Comparison with ACTA-graduates shows that in both programmes the weakest areas are implantology and practice management.

Adult↗

[Ergonomics in dental practice. Prevention of physical and mental overload].

In this article two important issues in dental ergonomics are discussed: physical and mental stress. It is important for a dentist to stay aware of the balance between on one hand short term profit against various forms of stress, and on the other hand long term negative effects. Possible problems are described without going in more deeply into theoretical backgrounds. Practical suggestions for action are given for the dentist who wants to work with pleasure and in good health over a long period of time.

Dental Equipment↗

[Topics in clinical dentistry. Trends in the Dutch dental literature].

Aim of the study was to evaluate a method for selecting topics suitable for developing dental clinical practice guidelines in the Netherlands, based on an analysis of Dutch dental journals. A search for dental clinical topics was conducted by analysing Dutch dental journals, magazines and series over the period 1992-1997. The numbers of publications per topic were plotted against the publication years. The number of publications as well as the value of the slope of the linear regression were considered to be indicators of the importance of a topic. 'Dental implants (indication)' had the highest number of publications, followed by 'orthodontic treatment planning' and 'periodontology (indication)'. The topic 'practice hygiene' showed the highest value of the slope of the linear regression, followed by 'TMJ dysfunction' and 'dental implants (indication)'. With this method, it is feasible to detect changes and tendencies in the Dutch dental literature. It permits a selection of clinically relevant topics over a time span. It was concluded that this method may be very useful in the selection of a topic, but should probably be combined with other methods.

Dental Implants↗

[Is there a place for computer-assisted Post-Academic Dental Education (PAOT)? A survey from the period 1998-2008].

OBJECTIVE: To estimate the role of computer-CPED in the Netherlands to the year 2008. DESIGN: Computer-assisted learning is currently employed in many modern undergraduate dental curricula. It could also play an important role in providing continuing professional education in dentistry (CPED) to general dental practitioners. Computer-CPED offers teacher-independent and individualized interaction by distance learning. METHODS: A simulation study was conducted. Entry data were either derived from publications or were estimated. RESULTS: The results indicate that the demand for CPED will exceed the supply by 2002. CONCLUSION: The introduction of Computer CPED may substantially contribute to the supply of CPED-courses in de first decade of the next century. By 2008 about 25% of the CPED-courses could be provided by computer education.

Computer Communication Networks↗

[Re-restoration decisions].

OBJECTIVE: In this study an attempt was made to explain some of the interobserver variation in re-restoration decision making using. METHOD: A simplified re-restoration case was shown to 22 dentists who were asked what treatment decision they would make, and what factors would play a role in their decision. The treatment decisions were compared to the outcomes of a knowledge-system on re-restoration decision making. RESULTS: The dentists unanimously selected re-restoration as the treatment alternative. Half of the dentists preferred amalgam, and the other half chose composite as restorative material. This variation could be explained almost fully by the dentists' weighs on the factors 'tissue loss during preparation', 'restoration and preservation of the chewing function' and 'prognosis and durability of the restoration'. The knowledge system indicated that more than 80% of the dentists actually should have selected composite resin for a restorative material. CONCLUSIONS: It was concluded that the availability of knowledge and its application can explain variation in re-restoration decisions. Knowledge systems can be used in designing practice guidelines.

Decision Making↗

The effect of a multimedia interactive tutorial on learning endodontic problem-solving.

New technology may create additional opportunities for learning in dental education. One of these new features is a multimedia approach, courseware combining sound, text, stills and video with interactive learning. A multimedia program was developed to train dental students and dental practitioners in decision making and problem solving in endodontics. This study compared the effects of the multimedia program with a more traditional approach consisting of written information, without interaction. 28, 4th-year dental students at the University of Kentucky in Lexington, KY, USA were randomly assigned to the multimedia or the text-based groups. They were given a written pre-test using 2 cases of dental pain and were instructed to study independently using either the multimedia program (group A) or the written information (group B). No restrictions were imposed on the amount of time to be invested, and the total study time was recorded for each student. 3 weeks after the pre-test, the students completed the post-test. A total of 18 students completed both the pre-test and the post-test and their scores were included in the final data. Statistical analysis of the average scores using paired t-tests revealed no significant difference between the performance of the students in either group, indicating that the multimedia approach to learning endodontic problem solving may successfully replace traditional learning strategies.

CD-I↗

[Practice guidelines in dentistry. An insight into the Dutch situation].

Practice guidelines provide opportunities for monitoring and improving dental health care. A survey was conducted among 78 departments at dental societies, scientific dental associations and health care insurance companies in the Netherlands to obtain insight into the number and quality of practice guidelines available. The response rate was 67%. Written materials were analysed and 21 practice guidelines were identified as such. The results of the analysis indicate that many initiatives to construct and implement practice guidelines have been taken. However, these initiatives were insufficiently coordinated and existing guidelines may be subject to improvement. Main improvement would be to demonstrate the validity and reliability of the existing guidelines and, more in general, to provide a sound scientific basis to the development and implementation of practice guidelines.

Data Collection↗

[Towards a system of quality care in dentistry in the Netherlands].

Monitoring and improving the quality of rendered health care in a systematic way has been laid down in Dutch legislation. In Dutch family health care particularly, many initiatives have already been taken to improve the quality of health care utilizing a pre-defined systematic approach. In recent years various groups in The Netherlands took initiatives to maintain and improve quality of care in dentistry. This publication reports on some of the frequently used constructs and the state of the art in The Netherlands. A proposition for the development of a system of quality monitoring and improvement is presented. It is furthermore suggested that all parties involved should collaborate to achieve the joint goal.

Dentistry↗

Research directions and output in European dental schools.

Information pertaining to the research directions and output of dental schools in different countries is of importance in understanding intra- and inter- national differences amongst groups of dental practitioners. The research output of European dental schools has been assessed quantitatively and qualitatively on the basis of published abstracts of research presentations at IADR-meetings during 1993. These data are compared with comparable data for 1990/91. The results indicate that European dental schools are substantially different in terms of research output relative to total population, with the UK at one extreme and Italy at the other. The UK, Denmark, The Netherlands, Sweden and Norway are highly ranked while Portugal, Spain, Italy, Germany and France have low rankings, according to the method used. Periodontology, plaque, dental materials, and restorative dentistry would appear to be the principal foci of research. Possible ways of strengthening the coordination and the efficiency and effectiveness of dental research at the European level are discussed. It is suggested that the creation of centres of excellence and research networks are approaches to be considered. An unresolved problem will be the contradictory requirements from educational and research perspectives in relation to the training of dental practitioners.

Dental Materials↗