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Diabetes mellitus (DM) causes an increased production of free radicals that can impair bone healing. Melatonin is a hormone secreted mainly by the pineal gland, which participates in the neutralization process of free radicals. Objective The aim of this study was to investigate histologic and biochemical effects of supplemental melatonin administration on bone healing and antioxidant defense mechanism in diabetic rats.Material and Methods Eighty-six Sprague-Dawley male rats were used in this study. Diabetes mellitus was induced by intraperitoneal (i.p.) administration of 65 mg/kg streptozotocin (STZ). Surgical bone defects were prepared in the tibia of each animal. Diabetic animals and those in control groups were treated either with daily melatonin (250 μg/animal/day/i.p.) diluted in ethanol, only ethanol, or sterile saline solution. Rats were humanely killed at the 10th and 30th postoperative days. Plasma levels of Advanced Oxidation Protein Products (AOPP), Malondialdehyde (MDA), and Superoxide Dismutase (SOD) were measured. The number of osteoblasts, blood vessels and the area of new mineralized tissue formation were calculated in histologic sections.Results At the 10th day, DM+MEL (rats receiving both STZ and melatonin) group had significantly higher number of osteoblasts and blood vessels as well as larger new mineralized tissue surfaces (p<0.05 for each) when compared with DM group. At the 30th day, DM group treated with melatonin had significantly lower levels of AOPP and MDA than those of DM group (p<0.05).Conclusion Melatonin administration in STZ induced diabetic rats reduced oxidative stress related biomarkers and showed beneficial effects on bone healing at short term.

Objectives: The aim of this study was to compare diagnostic accuracy of cone beam CT (CBCT) and multislice CT in artificially created fractures of the sheep mandibular condyle. Methods: 63 full-thickness sheep heads were used in this study. Two surgeons created the fractures, which were either displaced or non-displaced. CBCT images were acquired by the NewTom 3G H CBCT scanner (NIM, Verona, Italy) and CT imaging was performed using the Toshiba Aquillon H multislice CT scanner (Toshiba Medical Systems, Otawara, Japan). Twodimensional (2D) cross-sectional images and three-dimensional (3D) reconstructions were evaluated by two observers who were asked to determine the presence or absence of fracture and displacement, the type of fracture, anatomical localization and type of displacement. The naked-eye inspection during surgery served as the gold standard. Inter-and intra-observer agreements were calculated with weighted kappa statistics. The receiver operating characteristics (ROC) curve analyses were used to compare statistically the area under the curve (AUC) of both imaging modalities. Results: Kappa coefficients of intra-and interobserver agreement scores varied between 0.56 -0.98, which were classified as moderate and excellent, respectively. There was no statistically significant difference between the imaging modalities, which were both sensitive and specific for the diagnosis of sheep condylar fractures. Conclusions: This study confirms that CBCT is similar to CT in the diagnosis of different types of experimentally created sheep condylar fractures and can provide a cost-and doseeffective diagnostic option.

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