Evaluation of stress distributions in endodontically treated anterior incisors under occlusal and trauma-induced forces following various restoration treatments: A finite element analysis.

BACKGROUND: The aim of this study was to calculate the stress distribution of fiberglass post associated with resin composite crown restoration and fiberglass posts with zirconia restorations in mature and immature endodontically treated central maxillary incisor under various loading conditions. MATERIALS AND METHODS: The study created six different study models in a virtual environment: healthy mature maxillary central teeth, intact immature maxillary central teeth, mature maxillary central teeth with fiberglass post associated with resin composite crown restoration, immature maxillary central teeth with fiberglass post associated with resin composite crown restoration, mature maxillary central teeth with fiberglass posts and zirconia restoration, and immature maxillary central teeth with fiberglass posts and zirconia restoration. Loading conditions simulating mastication, trauma, and bruxism were applied to each of the models at different angles and amounts. The von Mises and the maximum and minimum principal stress values in tooth structures (dentin) and support structures (bone, PDL) and materials were observed using finite element stress analysis. RESULTS: The highest stress values in the tissue and the restoration structure were observed for masticating force and crowns rehabilitated with zirconia restorations. None of the compared loading conditions and restorations showed destructive stress values on periodontal ligament or bone. CONCLUSION: The mature and immature endodontically treated central maxillary incisors can be better rehabilitated using fiberglass post associated with resin composite crown restoration and may be preferred to zirconia restorations in order to reduce the stresses on the surrounding tissues and teeth. However, further clinical studies are needed to fully explore this topic.

HPLC-DAD Analysis and Versatile Bioactivities of Turkish Sunflower Honeys Using Chemometric Approaches.

Sunflower honey (SH) is bright yellow, fragrant, pollen-flavoured, slightly herbaceous and has a unique taste. The present research aims to examine the enzyme inhibitory, antioxidant, anti-inflammatory, antimicrobial and anti-quorum sensing activities and phenolic compositions of 30 sunflower honeys (SHs) produced from several regions of Turkey with chemometric study. SAH from Samsun exhibited the best antioxidant activity in ß-carotene linoleic acid (IC50 : 7.33±0.17 mg/mL) and CUPRAC (A0.50 : 4.94±0.13 mg/mL) assays, anti-urease activity (60.63±0.87 %) and anti-inflammatory activity against COX-1 (73.94±1.08 %) and COX-2 (44.96±0.85 %). SHs exhibited mild antimicrobial activity against the test microorganisms while they showed high quorum sensing inhibition zones measured in the range of 42-52 mm against the CV026 strain. The phenolic composition was determined by high performance liquid chromatography with diode array detection (HPLC-DAD) system and levulinic, gallic, p-hydroxybenzoic, vanillic and p-coumaric acids were identified in all studied SHs. The classification of SHs was performed the using PCA and HCA. This study revealed that phenolic compounds and biological properties are effective in classification of SHs according to their geographical origin. The results suggest that studied SHs could be valued as potential agents with versatile bioactivities in oxidative stress-related disease, microbial infections, inflammation, melanoma, and peptic ulcer.