Assessment of the systemic effects of low-level laser therapy (LLLT) on thyroid hormone function in a rabbit model.

The aim of this study was to assess the effects of low-level laser therapy (LLLT) applied to a dental extraction socket on thyroid gland function in a rabbit model, based on serum triiodothyronine and thyroxine levels. Sixteen male New Zealand rabbits were randomly distributed into two groups: a control group (non-irradiated animals) and an experimental group (irradiated animals: one irradiation point in the extraction socket of the lower incisor). Animals in the experimental group were irradiated with an aluminium gallium arsenide diode laser (AlGaAs; wavelength 830 nm, 40 mW, CW laser), for 13 days, every 48 h, at a dose of 6 J/cm(2) per session, resulting in a total dose of 42 J/cm(2). Serum triiodothyronine and thyroxine levels were measured in both groups before extraction and on the last day of observation (day 15). There were no statistically significant differences between the groups in pre- and post-irradiation triiodothyronine and thyroxine values. With the irradiation protocol used in this study, LLLT did not affect thyroid function in rabbits as assessed by circulating serum triiodothyronine and thyroxine levels.

Marginal adaptation and microleakage of five root-end filling materials: an in vitro study.

AIM: Endodontic surgery consists of several procedures which involve the endodontic space or the root canal and is performed as an alternative to unsuccessful outcomes or complications following endodontic treatments. The aim of the study was to evaluate the sealing ability of five root-end filling materials. METHODS: Fifty human single rooted teeth were treated endodontically; roots were resected at 3 mm from the apex, and root end cavities were prepared with ultrasonic tips. Root ends were filled with one of the following materials: silver amalgam (control group); mineral trioxide aggregate; white Portland cement; Vitremer; and Fuji Ortho. Apical sealing was evaluated by evaluating microleakage of 50% silver nitrate solution. The apical portion of the roots was sectioned to obtain 1-mm thick transversal slices, and epoxy resin replicas of these apical slices were produced. A scanning electron microscope (SEM) was used for analyses. The Kruskal-Wallis test and a multiple comparisons test were used for statistical data analysis. RESULTS: Results showed microleakage and variable adaptation gaps on the interface between dentin and root-end filling material in all specimens. CONCLUSION: All the studied materials exhibited some degree of apical microleakage and marginal gaps. No correlation was found between data obtained from analyses of apical sealing and marginal adaptation.