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Biomedical subjects

E H Verdonschot

Publications and source records attributed to E H Verdonschot.

71 records · Page 4Linked to original sources
PubMed1991

Approximal caries diagnosis using fiber-optic transillumination: a mathematical adjustment to improve validity.

Several studies were conducted recently to evaluate the use of Fiber-Optic Trans-Illumination (FOTI) in the diagnosis of approximal carious lesions. All these studies utilized radiographic readings to validate the FOTI diagnoses. Other investigations studied the value of radiographic readings using more solid validating techniques, which made it possible to judge the true state of decay, such as histology, cavity preparation and microradiography. In this study, data from both types of studies were used to estimate the validity of FOTI diagnosis of approximal caries relative to the true status of decay through correction for radiographic misclassification. The results indicate that particularly the sensitivity of FOTI diagnosis has yet to be determined.

Dental Caries↗
PubMed1991

Optical quantitation and radiographic diagnosis of incipient approximal caries lesions.

The objectives of this study were to test the applicability of photocell measurements in approximal caries diagnosis and to evaluate the use of radiographs as validating criterion. Forty extracted premolars were selected, and the progression of the approximal lesions was graded clinically and radiographically by three examiners. Each tooth was transilluminated from the occlusal surface, and the throughput of light at the approximal surface was measured by a photocell. Together with clinical examination, the results of microradiographic analysis served as validating criterion in this study. The results indicate that photocell measurements can be useful in the diagnosis of incipient approximal caries lesions. Radiographs have a restricted value as validating criterion in diagnostic studies pertaining to incipient caries.

Bicuspid↗
PubMed1990

A computer-aided image analysis system for area measurement of tooth root surfaces.

The characteristics of a computer-aided Image Analysis System (IAS) to conduct linear and area measurements on tooth root surfaces were investigated. The borders of the features to be measured were extracted from a digitized video image by histogram-based thresholding and binarization. The lengths and square areas were expressed in the number of pixels. The reference-length and area of one pixel were obtained through measurement of the diameter of a metal ball of known diameter in the same digital image. The validity of the IAS was tested using radiographs of teeth containing round metal restorations of known diameter and area. The accuracy of the length measurements ranged from -2.0 to 2.1%, whereas the accuracy of area measurement was between -5.3 and 0.8%. The precision of the IAS to identify the borders of a tooth root surface and to reproducibly calculate its area, expressed in a coefficient of variation, ranges from 0.49 to 4.11%. The results indicate that imaging techniques can be applied to obtain very accurate measurements of tooth root surfaces.

Dental Enamel↗
PubMed1985

[The slice onlay].

Explore the source record for details and available documents.

Dental Cavity Preparation↗
PubMed1981

Dental education in the Netherlands.

Dental education varies throughout the world as a result of the unique circumstances and needs of each country. The dental educator can derive benefit by comparing and contrasting different systems. Dental education in the Netherlands is characterized in this paper by summarizing several of it components. Dental practice is reviewed and the development of dental education traced. The structure and functioning of a typical school of of dentistry is discussed as well as admissions, student finances, curriculum, and certification. In addition, postgraduate and auxilliary education are reviewed.

Certification↗
PubMedDate not supplied

Performance of some diagnostic systems in the prediction of occlusal caries in permanent molars in 6- and 11-year-old children.

OBJECTIVES: Attempts have been made to develop diagnostic methods which enable an early diagnosis of occlusal lesions which are not detectable by visual inspection. The aim of this study was to compare the performance of visual inspection focused on finding signs of fissure decalcification and discoloration, visual inspection upon fibre-optic transillumination (FOTI), and electrical conductance measurements (ECMs) in predicting the onset of occlusal caries in 6- and 11-year-old children. METHODS: Fifty children aged 5-7 and 11-15 years, having first or second permanent molar teeth that were not exposed to the oral environment for more than half a year, participated in the study. Following baseline data recording, the diagnostic measurements were repeated six times at 6-month intervals over a period of 2.5 years. RESULTS: Data were collected at predefined sites in the fissures. During the study, 220 of the 652 sites, i.e. 75 of 197 molars in 31 of the 50 children were judged to require a sealant or a sealant restoration. Two examiners jointly decided on the decay status at the sites. Survival plots showed that ECMs were superior to FOTI and fissure discoloration in predicting the onset of occlusal caries, although the differences were small. CONCLUSION: ECM is a better predictor of occlusal caries than fissure discoloration and FOTI, although the differences among the performance of the three methods in this study were very small. A cost-effective analysis is envisaged to obtain insight into the practical value of ECMs in the prediction of occlusal caries and, thus, into the effectiveness of sealant application.

Adolescent↗
PubMedDate not supplied

Caries detection methods: can they aid decision making for invasive sealant treatment?

The decision to place sealants is a difficult one, and it has been suggested that in a low risk population it may be efficient to wait until caries is detected in the fissure. An invasive sealant technique with fissure preparation may then be indicated. The diagnostic method used in the indication of such a procedure should accurately detect both dentine caries and sound fissures: high sensitivity for dentine caries (at D3 threshold) with high specificity for enamel caries (at D1 threshold). The aims of this study were to assess the diagnostic performance of selected diagnostic methods at normal cut-offs for traditional dentine caries detection and at reduced cut-offs in relation to the desired performance mentioned above, and to assess whether fissure opening allows for accurate visual detection of dentinal caries. Data were obtained from 230 occlusal sites of 101 extracted human molar teeth. Diagnostic methods used on the entire sample were: visual inspection, electrical conductance measurements and laser fluorescence measurements. The sample was then divided into two groups. Group 1 was subjected to visual inspection after application of a dye. Group 2 was subjected to visual inspection after fissure opening only, and after subsequent dye application. Validation was performed by histological investigation. The results with cut-offs normally used in dentine caries detection were roughly in accordance with the literature, except for laser fluorescence. The sensitivity of visual inspection for dentinal caries (D3) was 17% before and 70% after fissure opening. Using reduced cut-offs, a 100% sensitivity (D3) was achieved with 2 methods, but this also resulted in 63 or 87% false positive diagnoses of sound surfaces. Visual inspection and electrical methods both showed a moderate to high sensitivity (D3) with a higher than 50% specificity (D1). It was concluded that visual inspection and electrical methods at reduced cut-offs may aid the indication of invasive sealant treatment. The visual detection of dentinal caries is substantially increased, but not perfect after fissure opening.

Area Under Curve↗