Patch test results in dental staff with dermatitis.

BACKGROUND: Dental workers are exposed to allergenic materials in the workplace. OBJECTIVES: To summarize patch test results in dental staff with work-related dermatitis. MATERIALS AND METHODS: Cross-sectional study of dental staff with dermatitis was conducted. Symptoms, clinical findings and results from patch tests with 40 dental allergens were summarized. RESULTS: Of 329 participants, 155 (47.1%) had at least one positive patch reaction. The highest frequency of positive reactions was observed for metals (38.6%), acrylics (7.3%) and additives in acrylic resins (3.6%). One hundred and eighty-five (56.2%) participants were currently symptomatic; in this group, 79 (42.7%) had current dermatitis. Thirty-eight patients had at least one positive patch test considered occupationally related to their current dermatitis. CONCLUSION: Almost half of the dental staff with dermatitis had at least one positive patch test and approximately 12% had current occupational relevance of the allergens. Our results underscore the importance of patch testing in the evaluation of dental staff with dermatitis.

The effect of experimental conditions in root dentin microcracks detection by micro-computed tomography.

The aim of the study was to assess the effect of different experimental conditions on registration of microcracks by means of micro-computed tomography. Twenty roots of permanent lower incisors were instrumented with SAF system, filled with a single-cone technique and retreated with the Pro Taper Universal Retreatment system. Each sample was measured in dry, water, and moist conditions. The dry scanning was done after drying of the roots for a period of 4 h in ambient conditions followed by a second observation in wet environment after 48 h of rehydrating in distilled water. A time scan was performed to measure the dentin shrinkage while drying the samples in the tomograph's device compartment. All roots underwent complex inhomogeneous shrinkage and deformation due to the internal stress upon dehydration. This deformation opened the existing cracks to an extent above the current resolution of today's laboratory computed tomography scanners. Contrary, rehydration of the dentin reversed the deformation thus closing some of the cracks below the computed tomography resolution making them undetectable. The first dehydration of dentin may be a source of cracks initiation itself.