Postprocessing of all-zirconia restorations in digital dental radiographs: a quality assurance predicament

Improvements in image quality after optimization in digital intraoral radiographs

BACKGROUND

Digital intraoral radiographic exposures are optimized largely on the basis of subjective assessment of diagnostic image quality. This study presents an objective approach to optimize radiographic exposure settings for digital intraoral radiographic systems.

METHODS

Seven size 2 digital intraoral systems were assessed for image quality and determination of optimal exposure following the protocol specified in American National Standard Institute/American Dental Association Standard No. 1094: Quality Assurance for Digital Intra-Oral Radiographic Systems. A ProX radiograph unit (Planmeca) at 63 kVp and 6 mA was used to obtain radiographs of the Dental Digital Quality Assurance phantom. ImageJ software (National Institutes of Health) was used to quantify dynamic range and spatial resolution, and contrast perceptibility was evaluated visually. Optimal exposure is the setting with the maximal contrast perceptibility and spatial resolution while displaying the full dynamic range. After image optimization, a custom phantom consisting of an endodontically prepared tooth was imaged to evaluate the file position relative to the apex for each system. Differences in distances between file position relative to the root apex at the optimal exposure as well as 1 increment above and below were measured.

RESULTS

Radiographic images obtained at the optimal exposure yielded better visualization and more accurate measurements of the file tip relative to the apex.

CONCLUSIONS

Optimizing radiographic exposures improves image quality and accuracy in clinical decisions.

PRACTICAL IMPLICATIONS

Improvement in image quality and better accuracy in actual distance of the endodontic file to the radiographic apex coupled with complete cleaning, shaping, and obturation of the canal should lead to better endodontic treatment outcomes.

The Importance of the ANSI/ADA Standard for Digital Intraoral Radiographic Systems: A Pragmatic Approach to Quality Assurance

The need for quality assurance (QA) for digital dental radiography has existed since the introduction of digital imaging; however, the methods and phantoms required to achieve it were not available. This resulted in a chaotic approach to address QA based largely upon subjective analysis of image quality. The American National Standards Institute (ANSI)/American Dental Association (ADA) Quality Assurance Standard 1094 for Digital Intraoral Radiographic Systems (DIRS) presents a paradigm shift to a scientific and objective method of QA rather than one based on subjective assessments. This standard takes into account the contributions of all components of the digital imaging chain that affect final image quality rather than assessing the various components in isolation. The optimal image is determined for each DIRS through objective analysis of the image quality properties of dynamic range, spatial resolution, and contrast perceptibility. Image optimization, a critical component of a quality assurance program, is the proper balance between diagnostic image quality and radiation dose to the patient. This publication counters disseminated myths and misconceptions with scientific evidence and will help dental practitioners appreciate and understand the benefits of the new ANSI/ADA Standard on QA for DIRS.