Post-processing of all Zirconia Restorations in Digital Dental Radiographs: a Quality Assurance Predicament

Publication date: Available online 31 December 2018

Source: Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology

Author(s): Allison Buchanan, Amelia Orta, Sajitha Kalathingal

Abstract

Objectives

To describe a quality assurance issue, producing non-diagnostic high contrast radiographs, when imaging teeth restored with all zirconia crowns on bitewing radiographs.

Methods

All zirconia crowns were imaged with DIGORA Optime Photostimulable Phosphor (PSP) plates (Soredex/Orion Corp., Helsinki, Finland). To assess differences in software processing, the PSP plates were scanned into third party software as well as directly into the twain and native software provided by the manufacturer. Gamma correction, histogram stretch, and scanner resolution settings were adjusted. Vertical bitewings were acquired to increase anatomical coverage.

Results

Scanning into third party software or directly into the twain and native software did not improve contrast. Shifting the lower limit of the histogram stretch to 3 with a gamma correction of 2 resolved the problem. Neither scanner resolution setting nor vertical bitewings improved contrast.

Conclusions

The high contrast non-diagnostic radiographs result from imaging software not effectively displaying the available grey scale. The software processing error appears to be initiated by the high attenuation characteristics of zirconia. Consequently, radiographs with a high zirconia crown to normal anatomy ratio are particularly susceptible.

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