Charge-coupled device panoramic radiography: effect of beam energy on radiation exposure.

OBJECTIVE: To determine the consequences for entrance exposure of varying the beam energy and operating current for panoramic radiography using a charge-coupled device receptor. MATERIAL AND METHODS: Images were made of a RANDO average man phantom (Alderson Research Laboratories, Stamford, CT) at kVcp settings of 60, 66, 70 and 80 and an mA of 2.0, 3.2, 6.4 and 10.0. The exposure cycle was set as recommended by the manufacturer at 17.6 s. Diagnostic image quality was rated by a panel of two oral and maxillofacial radiologists and one oral and maxillofacial pathologist. Entrance exposures were assessed using a 3 cc ionization chamber placed at the beam entry points while imaging the molar, premolar, and anterior teeth both using the DigiPan (Trophy Radiologie, Vincennes, France) CCD receptor and conventional T-Mat G film/Lanex Regular screens (Eastman Kodak, Rochester, NY, USA). RESULTS: Acceptable image quality was attained with combinations of 60 kVcp and 3.2, 6.4 or 10 mA, 70 kVcp and 2.0, 3.2 or 6.4 mA; at 80 kVcp irrespective of the mA it was unacceptable. The maximum reduction in entrance dose was 77%, averaged over the three sites, at 70 kVcp and 2 mA. CONCLUSION: The DigiPan receptor produces satisfactory images with saving in entry exposure saving of approximately 70% when compared with a conventional film/rare earth screen combination.

Evaluation of oral cancer screening.

BACKGROUND: Oral cancer screening procedures are designed to collectively allow early detection of cancers in a body area accessible to visual and physical examination, as well as to facilitate timely treatment, awareness, and the ongoing education of the public. METHODS: A state fair was selected for this activity because of the availability of a random population compatible with meeting these goals. A total of 1,151 individuals participated in this free elective activity. RESULTS: Of this number 4.17% were deemed to have oral pathologic states necessitating professional intervention, and 1.82% were clinically diagnosed as having potential dysplastic or precancerous lesions. No clinical oral cancer was detected in this population. Nevertheless, by virtue of screening and detecting clinically premalignant lesions, the screening test advanced the diagnosis of potential oral cancers. CONCLUSIONS: The outcome adds support to oral cancer screening as a procedure applicable in reducing morbidity and mortality from oral cancers.

Computer expert system for the histopathologic diagnosis of salivary gland neoplasms.

The design, development, and testing of a prototype interactive histopathologic expert system capable of diagnosing 15 types of primary salivary gland neoplasms is described. The system incorporates a multiple subprogram modular design and makes use of multiple reasoning methods including: data-driven and goal-directed rule-based reasoning, linear pattern recognition, and Bayesian classification. Its user interface incorporates both a "hypertext" context-sensitive information assistance facility and the video display of stored and digitized photomicrographic images. The system can report a differential diagnosis of its findings with assessment of its confidence in its diagnosis. The system's performance was evaluated in a series of tests. The results of a weighted kappa analysis of the system's diagnoses versus those of four oral pathologists for 20 salivary gland neoplasms indicated no statistical difference in diagnostic performance between the system and the human experts and each of the experts in relationship to the others (Wilcoxon rank sums test). A modified version of Turing's test of artificial intelligence demonstrated no statistically significant difference in the system's diagnoses versus the diagnosis of four human expert pathologists (Fisher's exact test). The knowledge and experience gained in the development and testing of the expert system described in this study have demonstrated the validity of histopathologic diagnostic expert systems in a selected area of oral pathology.

Diagnosis of selected pulpal pathoses using an expert computer system.

The diagnosis of dental pain that results from a pulpal pathosis may prove to be a confusing and complex issue for both dental students and experienced clinicians alike. A computerized diagnostic expert system, COMENDEX, was developed to aid in the clinical diagnosis of pulpal pathosis and to provide a rapid, accurate second opinion when a human consultant is not readily available. The vast majority of diagnostic expert systems use a single reasoning methodology as their inference mechanism. COMENDEX is a prototype hybrid expert system that combines and exploits the best aspects of both rule-based and statistical reasoning methodologies. The COMENDEX endodontic diagnostic system was tested to determine the validity and accuracy of its diagnoses by the use of a variant of Turing's test and weighted kappa statistic. The promising result obtained from the initial tests suggests that an expert system using this type of hybrid reasoning methodology is well suited to the area of endodontic diagnosis and may prove highly successful if expanded to include other problem areas in oral diagnosis.

Computer applications in oral diagnosis.

Eventually, computer technology may be used in the home or practice to satisfy continuing education requirements. Additionally, this technology may be used by state licensing agencies as a component of their testing procedure. At the present time, a Patient Simulation Consortium and Electronic Curriculum Consortium have been established within the American Association of Dental Schools.7, 15 These groups, and others, will continue to develop and test new technologies for use in dentistry.