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Objectives: The objective of this study was to examine a new blue light diode laser system (445 nm) for dental soft tissue surgery on cellular level., Materials and Methods: An in vitro cell culture model was established to evaluate the effects of the 445-nm diode laser in comparison to an established infrared diode laser (IR). Monolayer cell cultures were irradiated and wound healing was morphometrically measured. Fluorescence staining was used for proof of potential DNA double-strand breaks as well as cytoskeleton alterations. Cellular live/dead discrimination was performed and temperature development during laser irradiation was measured with a thermographic infrared camera., Results: A characteristic zone formation was detected after irradiation with both wavelengths. Despite a larger wound area after irradiation with 445 nm, due to its higher temperature development, this laser system showed a faster wound healing in comparison to the IR laser. No increase of devitalized cells was documented with higher distances between laser tip and cell layer and thus without thermal interaction. Neither cytoskeleton alteration nor DNA double-strand breaks could be recorded after irradiation in non-contact mode., Conclusions: The blue diode laser system demonstrated an excellent direct thermal coupling to cells and tissues without side effects even by reduced power settings., Clinical Relevance: The blue diode laser seems to be a promising technology for clinical application due to high absorption of blue light without major side effects in adjacent tissues even by reduced power settings.

The aim of this in vitro study was to compare cone-beam computed tomography (CBCT) to conventional radiography (RG) in the assessment of the periodontal ligament space. A phantom with a variable "artificial" periodontal ligament space (0, 100, 200, 300, and 400 microm) was used as a model. The examinations were performed simultaneously with RG and NewTom 9000 digital volume tomograph. Assorted after increasing widths, 15 RGs and 15 CBCT images were presented for judgment to 20 dentists (DD), 20 dental assistants, and 20 dental students. Several weeks later, the same images were randomly mixed and presented to the same 20 DD again. The trial shows that RG gaps wider than 200 microm could be correctly identified by all participants with an accuracy of nearly 100%. A significant difference was observed between the modalities (p<0.05 and p<0.001) where conventional RGs performed better than CBCT for assessment of periodontal ligament space. Interobserver variation in relation to each technique was evaluated and no significant difference was found (p>0.05). In subjective evaluations of image quality with CBCT, the results were basically inferior for images of artificial periodontal ligament space, regardless of the experience of the observers.