Successful Non-Surgical Root Canal Treatment on Auto-Transplanted Maxillary Premolar with Apical Periodontitis.

Auto-transplantation is a procedure that replaces traumatized or congenitally missing teeth. While most auto-transplanted teeth are successfully integrated into recipient sites, the donor tooth may develop apical periodontitis, causing early failure. In the present case report, the periodontic resident performed the procedure on a 15-year-old male by selecting donor teeth #4 and #13 and transplanting them at recipient sites #29 and #20, respectively. After 6 weeks, the patient was referred to the endodontic resident for evaluation of tooth #20 due to symptom development. While one auto-transplanted tooth (donor tooth #4, recipient site #29) was successfully integrated, the other (donor tooth #13, recipient site #20) was unsuccessful: the patient was diagnosed with pulp necrosis and a chronic apical abscess. Because of the patient's age, collaboration among periodontic, endodontic, and orthodontic residents/specialists informed the clinical decision to pursue non-surgical root canal treatment (NSRCT) rather than extraction. The canal was cleaned and shaped to a size #80 using copious irrigation of 2.5% sodium hypochlorite (NaOCl), followed by 17% ethylenediaminetetraacetic acid (EDTA) via the EndoVac Negative Pressure Irrigation system. The tooth was dried with paper points, and then calcium hydroxide was mixed with 2.5% NaOCl and placed with an amalgam carrier 2 mm from the radiographic apex. The tooth was next temporized with Teflon tape and Fuji TRIAGE. Four weeks later, after confirming the patient was asymptomatic and tooth mobility had decreased, the canal was obturated using EndoSequence Bioceramic Root Repair Material Fast Set Putty in 2 mm incremental layers to achieve a three-dimensional fill and create an apical plug to prevent gutta-percha extrusion, then backfilled in incremental layers of gutta-percha to the cementoenamel junction (CEJ). At the 8-month follow-up, the patient was asymptomatic, and the periodontal ligament (PDL) had no signs of periapical pathology. When teeth undergoing auto-transplantation procedures develop apical periodontitis, NSRCT can be implemented.

Novel poly(ε-caprolactone)/amino-functionalized tannin electrospun membranes as scaffolds for tissue engineering.

Poly(ε-caprolactone) (PCL) is a hydrophobic and cytocompatible aliphatic polyester that has been used to produce PCL-based nanofibrous for both wound healing and tissue repair. However, the high hydrophobicity and low water adsorptive have been challenges for developing PCL-based materials for use in tissue engineering field. Here, we report a new polymer (a hydrophilic amino-functionalized tannin (TN)) that is associated with PCL for developing PCL-TN blends at different PCL:TN weight ratios (100:0, 95:5, 85:15 and 78:22). PCL:TN ratio may be tuned to modulate hydrophilicity and cytocompatibility of the nanofibers. The neutralization step and surface wettability played an important role in the attachment of human adipose-derived stem cells (ADSC cells) on PCL-TN membranes. Also, fluorescence images confirmed great proliferation of ADSC cells on the PCL-TN electrospun surfaces. Yet, neutralized PCL-TN nanofibers promoted bactericidal activity against Pseudomonas aeruginosa. These membranes have potential to be used as scaffolds for tissue engineering purposes.

Lipoprotein Receptor-related Protein 6 Signaling is Necessary for Vasculogenic Differentiation of Human Dental Pulp Stem Cells.

The aim of this study was to evaluate the effects of Wnt signaling through lipoprotein receptor-related protein 6 (LRP6) and Frizzled6 on the endothelial differentiation of dental pulp stem cells (DPSCs). DPSCs were stably transduced with enhanced green fluorescent protein (EGFP)-tagged lentiviral vectors (short hairpin RNA-LRP6, short hairpin RNA-Frizzled6, or empty vector controls). We evaluated the effects of LRP6 and Frizzled6 on expression of endothelial markers and on capillary tube formation mediated by DPSCs induced with recombinant human Wnt1 (rhWnt1) and/or recombinant human vascular endothelial growth factor165 (rhVEGF165). In vivo, tooth slices/scaffolds were seeded with LRP6-silenced, Frizzled6-silenced, or vector control DPSC cells and transplanted into immunodeficient mice. The density of blood vessels generated by DPSCs differentiated into vascular endothelial cells was analyzed by immunohistochemistry for EGFP. The rhWnt1 and rhVEGF165 induced expression of active ß-catenin in control DPSCs and in Frizzled6-silenced DPSCs, but not in LRP6-silenced DPSCs. Furthermore, VEGF and interleukin-8 were downregulated in LRP6-silenced DPSCs, but not in control DPSCs or in Frizzled6-silenced DPSCs (P < .05). Likewise, rhWnt1 and rhVEGF165 induced expression of the endothelial marker VEGF receptor-2 in control DPSCs and in Frizzled6-silenced DPSCs, but not in LRP6-silenced DPSCs. These data correlated with a trend for lower density of capillary sprouts generated by LRP6-silenced DPSCs when compared with control DPSCs in Matrigel. In vivo, tooth slice/scaffolds seeded with DPSC-short hairpinRNA-LRP6 cells showed lower density of human blood vessels (ie, EGFP-positive blood vessels), when compared with tooth slice/scaffolds seeded with vector control cells (P < .05). Collectively, these data demonstrated that LRP6 signaling is necessary for the vasculogenic differentiation of human DPSCs.

Cytotoxicity and genotoxicity of natural resin-based experimental endodontic sealers.

OBJECTIVES: The development of endodontic sealers based on natural resins seems to be promising, given their improved biological properties. This study evaluated the cytotoxic and genotoxic effects of two experimental root canal sealers, based on extracts from Copaifera multijuga and Ricinus communis (castor oil polymer), comparing them to synthetic resin-based sealers: a single methacrylate-based, a multi-methacrylate-based, and an epoxy resin-based sealers. MATERIALS AND METHODS: Sealers were prepared, set, and exposed to cell culture medium for 24 h at 37 °C with CO2. V79 cells were exposed to serial dilutions of the extracts of each sealer for 24 h. Cell viability was measured by the MTT assay and genotoxicity was assessed by the formation of micronuclei. RESULTS: The single methacrylate-based sealer had the most cytotoxic effects, with significant reduction in cell viability in all dilutions of the extract. The castor oil polymer-based sealer was, on the other hand, the most biocompatible sealer, with no cytotoxic effects at any concentration. All tested sealers were not genotoxic, excepting the single methacrylate-based sealer. CONCLUSIONS: The tested natural resin-based sealers presented low cytotoxic and no genotoxic effects on cell cultures. CLINICAL RELEVANCE: These results may suggest a good alternative to develop new endodontic sealers, in order to achieve better biological response and healing, when compared to commercially available sealers.

Effectiveness and biological compatibility of different generations of dentin adhesives.

OBJECTIVES: Besides possessing good mechanical properties, dental materials should present a good biological behavior and should not injure the involved tissues. Bond strength and biocompatibility are both highly significant properties of dentin adhesives. For that matter, these properties of four generations of adhesive systems (Multi-Purpose/Single Bond/SE Plus/Easy Bond) were evaluated. MATERIALS AND METHODS: Eighty bovine teeth had their dentin exposed (500- and 200-µm thickness). Adhesive was applied on the dentin layer of each specimen. Following that, the microshearing test was performed for all samples. A dentin barrier test was used for the cytotoxicity evaluation. Cell cultures (SV3NeoB) were collected from testing materials by means of 200- or 500-µm-thick dentin slices and placed in a cell culture perfusion chamber. Cell viability was measured 24 h post-exposition by means of a photometrical test (MTT test). RESULTS: The best bonding performance was shown by the single-step adhesive Easy Bond (21 MPa, 200 µm; 27 MPa, 500 µm) followed by Single Bond (15.6 MPa, 200 µm; 23.4 MPa, 500 µm), SE Plus (18.2 MPa, 200 µm; 20 MPa, 500 µm), and Multi-Purpose (15.2 MPa, 200 µm; 17.9 MPa, 500 µm). Regarding the cytotoxicity, Multi-Purpose slightly reduced the cell viability to 92% (200 µm)/93% (500 µm). Single Bond was reasonably cytotoxic, reducing cell viability to 71% (200 µm)/64% (500 µm). The self-etching adhesive Scotchbond SE decreased cell viability to 85% (200 µm)/71% (500 µm). Conversely, Easy Bond did not reduce cell viability in this test, regardless of the dentin thickness. CONCLUSIONS: Results showed that the one-step system had the best bond strength performance and was the least toxic to pulp cells. In multiple-step systems, a correct bonding technique must be done, and a pulp capping strategy is necessary for achieving good performance in both properties. CLINICAL RELEVANCE: The study showed a promising system (one-step self-etching), referring to it as a good alternative for specific cases, mainly due to its technical simplicity and good biological responses.

Microhardness and sealing ability of materials used for root canal perforations.

Root perforations may lead to a loss of integrity in the root and periodontium, violations of the biologic periodontal distance, and injuries to periodontal tissue. This study sought to analyze the effect of root canal biomechanical preparation on the microhardness and the marginal sealing ability of different materials used to treat root perforations. Standard root perforations were performed in 96 bovine incisors. The teeth were divided into four groups (n = 24), based on the material used to treat those teeth: Mineral trioxide aggregate (MTA) (Group 1), MTA protected with cyanoacrylate (Group 2), MTA protected with glass ionomer (GI) cement (Group 3), and castor oil bean (COB) cement (Group 4). After root perforations were closed, the root canals were prepared biomechanically and teeth were sectioned longitudinally. Microleakage and microhardness of sealed perforations were assessed; microleakage data were submitted to analysis of variance (ANOVA) testing, while microhardness data were submitted to Dunnet and Tukey tests (p < 0.05). Group 4 reported the lowest amount of microleakage (0.65 mm), followed by Group 3 (1.02 mm), Group 1 (1.14 mm), and Group 2 (1.30 mm); however, no difference was detected among the groups. Groups 1-3 demonstrated significantly higher microhardness values compared to COB. It was concluded that the chemical and mechanical agents used during root canal preparation did not affect the sealing procedures. Administering surface protection to MTA did not improve microhardness or sealing.

Topographical, diametral, and quantitative analysis of dentin tubules in the root canals of human and bovine teeth.

The aim of this study was to evaluate the number and the diameter of dentin tubules in root canals, in the cervical, middle, and apical thirds, of human and bovine teeth. Twenty-four single-rooted, human premolars were divided into four groups (n = 6): GH1, 10 to 15 years; GH2, 16 to 30 years; GH3, 31 to 45 years; and GH4, 46 to 80 years; and 24 bovine incisors were divided into four groups (n = 6): GB1, central; GB2, lateral first; GB3, lateral second; and GB4, lateral third. The crowns were removed from the specimens, which were then debrided, sectioned longitudinally in the vestibular-lingual direction, and submitted to ultrasonic cleaning. Scanning electron microscopic evaluations were made with 1,000x and 5,000x magnification. According to the root thirds, statistically significant differences were found both for the number and the diameter of dentin tubules, with the cervical third presenting the highest mean values for both specimen types. As regards the number of dentin tubules, it was observed that the bovine specimens presented a significantly higher mean value than the human specimens; this difference was not observed when the diameters of the two types were compared.