Quality assurance of ceramic dental restorations by photographic transillumination.

Figure 1. Metal ceramic restoration, right side lighting. No detectable flaws. Quality assurance of indirect restorations should be performed by the dental laboratory before delivering the prosthetic parts to the clinician. Ultimately, it is the clinician’s responsibility to inspect and ensure, within the limits of clinically available technical and technological means, the quality of the prosthesis prior to insertion. Transillumination techniques in dentistry have been described as an aid in diagnosis as well as during the execution of various clinical procedures, including those for interproximal caries detection, endodontic visualization of dentinal defects, surgical localization of retained roots, location of the maxillary sinus floor and septa during sinus augmentation procedures, diagnosis of occult submucous cleft palate, and as a facilitator during arthroscopic puncture. In the specialty of prosthodontics, transillumination has been described thus far in the detection of microcracks in ceramic materials, based on the principle that subsurface cracks and flaws redirect light, resulting in darker shadows. Beck et al compared the sensitivity of transillumination with the fluorescent penetrant method (FPM). This technique consists of ceramic evaluation under fluorescent light after specimen immersion into a fluorescent liquid able to penetrate microscopic cracks. The technique can be used to detect microcracks in zirconia and feldspathic ceramic materials. The transillumination technique allowed a minimum crack length detection of 33 mm for feldspathic ceramic and 55 mm for zirconia ceramic. The FPM minimum crack detection was 17 mm for feldspathic and 18 mm for zirconia ceramics. Despite the increased sensitivity, the authors