Research projects of the dept. of Oral and Maxillofacial Radiology

This page describes the ongoing research projects of the department of Oral and Maxillofacial Radiology of the Academic Center for Dentistry at Amsterdam. Each section contains the title, a short description and the person to contact for more information.

• digital radiology (sensors, hardware, software, systems)
• observer performance (in relation to image quality; eye tracking; decision analysis)
• diagnostic systems (image quality; system interfaces; new technologies)
• diagnostic radiology (early detection of dental pathology using advanced imaging systems)
• diagnostic quality (related to observer capabilities and diagnostic requirements)

index of projects:

• Digital Radiology
• Localized CT
• Automated Image Analysis
• Quality Assurance
• Diagnostic Performance

• system performance
• image quality
• system implementation

1. Comparison of intra- and extra-oral digital systems and film based imaging

1a. Intra-oral Imaging

1b. Extra-oral Imaging

2. Effects of compression, scaling and filtering on image quality

Contact: Dr. Gerard C. H. Sanderink 

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Localized CT

• localized tomography
• 3D-visualization

1. Localized CT
2. 3D-Visualization (in progress)

Contact: Prof. Paul F. van der Stelt

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Automated Image Analysis

• caries
• bone healing around implants
• trabecular pattern

1. Automated detection of proximal caries lesions
2. Bone quality around dental implants
3. Quantification of structure and orientation of the trabecular pattern

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Quality Assurance

• dosimetry
• use of x-ray procedures in general practice

1. A quality assurance package system.
   A mail package suitable for the assessment of the quality of radiodiagnostic procedures in dental practice has been developed using simple components. This package can be used to measure to dose to patients due to dental intra-oral radiographic examinations. In addition, the parameters affecting the patient dose can be assessed. This system has been used in the Netherlands in more than 50% of the dental offices, to assess the exposure conditions and if necessary to optimize the conditions. The system is now being distributed in Greece for the same reasons.
2. Effects of digital radiographic sensor systems on the reduction of the patient dose in maxillo-facial radiography.
   The amount of dose reduction is related to the dose due to conventional film based radiography. Similarly, the diagnostic quality of different image acquisition systems is studied.
3. The influence of the development procedure on the quality of dental radiographs.
   The diagnostic quality of radiographs processed under varying development conditions is studied. The first study concerns the detection of incipient caries lesions.

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Diagnostic Performance

• observer strategy
• effect of experience on diagnostic performance

1. Eye movement tracking during the viewing of radiographs.

See for more information about the eye-movement project the abstracts of our presentations at the Farwest Image Perception Conference (October 1995 in Philadelphia PA, USA).

2. Decision support for increased efficacy in radiographic diagnosis of dental disease.

Recent studies carried out by ourselves and others indicate that dentists may be making errors in visual recognition of the features of disease from radiographs and subsequently compound these errors when combining data on the chances of disease subsequent to taking radiographs. Even teachers of dentistry also often differ in the value of taking radiographs for a patient and may ignore the costs involved along the diagnostic - treatment outcome pathway. Before radiographs are prescribed the dentist should judge whether the treatment outcomes for the patient will be positively affected by their availability. Although there is concern about the radiation dose to the patient from the unnecessary use of X-rays, there is also concern that dentists are on the one hand underprescribing radiographs and on the other misdiagnosing treatment need from the radiographs which are available. The goal of this line of research is to investigate the facets of knowledge which dentists need to come to the decisions to indicate the need for radiographs and from these radiographs the need to treat or refer the patient. By providing knowledge about the expected value of decision outcomes, patient selection factors and image recognition criteria where biases and omissions in knowledge exist the likelihood of disease being diagnosed from the features of disease on radiographs should lead to increased efficacy of diagnosis and treatment decision making. As part of this approach a clinical decision analysis model has been developed for two disease categories to show the effects of the accuracy of testing on the outcomes and costs of diagnosis and subsequent treatment.

1. Stheeman SE, Stelt PF van der, Mileman PA. Expert systems in dentistry. Past performance - future prospects. J Dent 1992; 20: 68-73.
   
2. Mileman PA, Mulder E, Weele LT van der. Factors influencing the likelihood of successful decisions to treat dentin caries from bitewing radiographs. Community Dent Oral Epidemiol 1992;20:175-80.
3. Mileman PA, Kievit J. Cost-effectiveness decision analysis of obtaining periapical radiographs of traumatized maxillary incisors. Dentomaxillofac Radiol 1992; 21:154-61.
4. Mileman PA, Kievit J. Editorial. Achieving efficacy in oral radiology- out of the woods, and into decision trees? Dentomaxillofac Radiol. 1992; 21: 115-7.
5. Stheeman SE, Mileman PA, Hof van 't MA, Stelt van der PF. Blind chance ? An investigation into the perceived probabilities of phrases used in oral radiology for expressing chance. Dentomaxillofac Radiol 1993;22:135-9.
6. Timmermans DRM, Mileman PA. Editorial. Lost for words:using verbal terms to express probabilities in oral radiology. Dentomaxillofac Radiol 1992;22:171-2.
7. Kwist T, Reit C, Esposito M, Mileman PA, Bianchi S, Petterson K, Andersson C. Prescribing endodontic retreatment: towards a theory of dentist behavior. Int Endodontic J 1994;27:285-90.
8. Stheeman SE, Mileman PA, Hof MA van 't, Stelt PF van der. Diagnostic confidence and the accuracy of treatment decisions for radiopaque periapical lesions. Int Endodont J 1994; 27: "in press".

Contact Dr. P.A. Mileman