End-user survey for digital sensor characteristics: a pilot questionnaire study

Evaluation of image quality parameters of representative intraoral digital radiographic systems

OBJECTIVE

The aim of this study was to compare imaging properties of 20 intraoral digital systems objectively.

STUDY DESIGN

Using a direct current x-ray source and a radiographic phantom, a series of radiographs was made from the lowest exposure time until the sensor saturated. Images were captured and stored. Incident exposures were measured using a radiation meter. Gray scale, spatial resolution, and contrast/detail detectability were evaluated. Presence of 7 distinct steps spanning the gray levels from 0 to 255 was used to define the exposure latitude. An "optimal" exposure, the lowest exposure where maximum spatial resolution and contrast/detail detectability were achieved, was determined.

RESULTS

The systems varied greatly in latitude, "optimal" exposure, and image quality. This may not be readily apparent to the naked eye or when clinical images are compared.

CONCLUSIONS

Objective assessment of image quality with a quality assurance tool makes it possible to evaluate and compare the various intraoral digital systems.

Questionnaire surveys of dentists on radiology

OBJECTIVES

Survey by questionnaire is a widely used research method in dental radiology. A major concern in reviews of questionnaires is non-response. The objectives of this study were to review questionnaire studies in dental radiology with regard to potential survey errors and to develop recommendations to assist future researchers.

METHODS

A literature search with the software search package PubMed was used to obtain internet-based access to Medline through the website www.ncbi.nlm.nih.gov/pubmed. A search of the English language peer-reviewed literature was conducted of all published studies, with no restriction on date. The search strategy found articles with dates from 1983 to 2010. The medical subject heading terms used were "questionnaire", "dental radiology" and "dental radiography". The reference sections of articles retrieved by this method were hand-searched in order to identify further relevant papers. Reviews, commentaries and relevant studies from the wider literature were also included.

RESULTS

53 questionnaire studies were identified in the dental literature that concerned dental radiography and included a report of response rate. These were all published between 1983 and 2010. In total, 87 articles are referred to in this review, including the 53 dental radiology studies. Other cited articles include reviews, commentaries and examples of studies outside dental radiology where they are germane to the arguments presented.

CONCLUSIONS

Non-response is only one of four broad areas of error to which questionnaire surveys are subject. This review considers coverage, sampling and measurement, as well as non-response. Recommendations are made to assist future research that uses questionnaire surveys.

In vitro comparison of digital and conventional bitewing radiographs for the detection of approximal caries in primary teeth exposed and viewed by a new wireless handheld unit

OBJECTIVES

The aim of this study was to compare the diagnostic quality of a new wireless handheld unit (ADX4000; Dexcowin Co. Ltd, Korea) on conventional bitewings and its LCD screen for the detection of approximal caries in primary teeth.

METHODS

In total, 108 approximal surfaces of primary teeth were examined in vitro by 3 observers. Conventional films were viewed under subdued lighting conditions on a conventional view box. Digital 3.5 inch images were displayed on the built-in monitor of the ADX4000 and digital 17 inch images were viewed on a 17 inch monitor. The true caries diagnosis was based on histological assessment of the approximal surfaces after sectioning the primary teeth. Receiver operating characteristic (ROC) curve (A(z)) analysis was used to assess the diagnostic quality of imaging modalities.

RESULTS

The areas under the ROC curves ranged from 0.786 (digital 17 inch) to 0.813 (digital 3.5 inch). No statistically significant differences were found between the three modalities for detecting approximal caries.

CONCLUSIONS

It was concluded that the diagnostic quality of conventional film and digital images, which were exposed and viewed by a new wireless handheld unit, was comparable.

Work flow with digital intraoral radiography: a systematic review

OBJECTIVE

This systematic review evaluates the six most frequently emphasized advantages of working with digital radiography: less working time, lower radiation dose to the patient, fewer retakes and errors, wider dynamic range, easier access to patient information and easier image storage and communication. Moreover, some clinical aspects and possible disadvantages of digital imaging that were not foreseen at the beginning of the digital era, such as patient discomfort, damage to the receptor, degradation of the image, cross-contamination and viewing conditions, were assessed.

MATERIAL AND METHODS

The literature search used the PubMed database with no limits and was performed during June to August 2009. Search strategies are described in the text for each of the mentioned tasks. A hand search of task-specific journals supplemented the search strategies.

RESULTS

Time seems to be saved when switching from film to digital imaging in dental practice, a dose reduction may not be obtained, retakes and errors may be increased, the dynamic range may be wider with photostimulable storage phosphor (PSP) plates but not with sensors, the effect on patient information has not been well studied and storage and communication create new challenges with regard to handling large files and image compression. In addition, patient discomfort seems to be pronounced with sensors compared with PSP plates and film, the PSP plate may be scratched in clinical use and a two-layer barrier seems to be needed to prevent contamination of the receptor. The type of monitor may not be of major concern if the image is viewed in a room with subdued light.

CONCLUSIONS

Not all of the predicted advantages with digital compared to film-based radiography hold true in daily clinical work. Of particular interest is the relationship between number of images, retakes and the dose given to the patient.

Detection of Proximal Caries in vitro Using Standard and Task-Specific Enhanced Images from a Storage Phosphor Plate System

Eight dentists evaluated 72 proximal surfaces of premolars with respect to all caries lesions and to lesions into dentine in digital images from a storage phosphor plate system. The images were processed in four different ways: (1) the default algorithm of the standard imaging system (DF); (2) an algorithm correcting for attenuation and visual response (AV), and two proprietary caries-specific enhancement algorithms (3) K1, and (4) K2, respectively. The lesions were validated by histological examination. There were no significant differences in the areas under the receiver operating characteristic curves between differently processed radiographs for the categories of all caries lesions and caries into dentine.