Emanuela Prado Ferraz

Nanotopography directs mesenchymal stem cells to osteoblast lineage through regulation of microRNA-SMAD-BMP-2 circuit.

The aim of this study was to investigate if chemically produced nanotopography on titanium (Ti) surface induces osteoblast differentiation of cultured human bone marrow mesenchymal stem cells (hMSCs) by regulating the expression of microRNAs (miRs). It was demonstrated that Ti with nanotopography induces osteoblast differentiation of hMSCs as evidenced by upregulation of osteoblast specific markers compared with untreated (control) Ti at day 4. At this time‐point, miR‐sequencing analysis revealed that 20 miRs were upregulated (>twofold) while 20 miRs were downregulated (>threefold) in hMSCs grown on Ti with nanotopography compared with control Ti. Three miRs, namely miR‐4448, ‐4708, and ‐4773, which were significantly downregulated (>fivefold) by Ti with nanotopography affect osteoblast differentiation of hMSCs. These miRs directly target SMAD1 and SMAD4, both key transducers of the bone morphogenetic protein 2 (BMP‐2) osteogenic signal, which were upregulated by Ti with nanotopography. Overexpression of miR‐4448, ‐4708, and 4773 in MC3T3‐E1 pre‐osteoblasts noticeably inhibited gene and protein expression of SMAD1 and SMAD4 and therefore repressed the gene expression of key bone markers. Additionally, it was observed that the treatment with BMP‐2 displayed a higher osteogenic effect on MC3T3‐E1 cells grown on Ti with nanotopography compared with control Ti, suggesting that the BMP‐2 signaling pathway was more effective on this surface. Taken together, these results indicate that a complex regulatory network involving a miR‐SMAD‐BMP‐2 circuit governs the osteoblast differentiation induced by Ti with nanotopography. J. Cell. Physiol. 229: 1690–1696, 2014.

Accidental Displacement of Impacted Maxillary Third Molar: A Case Report

An unusual case of an impacted right maxillary third molar that was accidentally displaced into the maxillary sinus during exodontia and was surgically retrieved almost 2 years later is described. The tooth was removed under general anesthesia, after maxillary sinus exposure through Caldwell-Luc approach. Postoperative recovery was uneventful. Six months after the retrieval surgery, the maxillary sinus was completely healed and the patient did not present any complaint.

Frey's syndrome after condylar fracture: case report

Freys syndrome is the occurrence of hyperesthesia, flushing and warmth or sweating over the distribution of the auriculotemporal nerve and/or greater auricular nerve while eating foods that produce a strong salivary stimulus. Freys syndrome is also known as auriculotemporal syndrome and gustatory sweating. We present a case of Freys syndrome after a condylar fracture and its treatment by internal rigid fixation. A review of the literature is provided along with mention of a simple test (Minors test) that can help in the diagnosis of this syndrome.

Titanium With Nanotopography Induces Osteoblast Differentiation by Regulating Endogenous Bone Morphogenetic Protein Expression and Signaling Pathway.

We aimed at evaluating the effect of titanium (Ti) with nanotopography (Nano) on the endogenous expression of BMP‐2 and BMP‐4 and the relevance of this process to the nanotopography‐induced osteoblast differentiation. MC3T3‐E1 cells were grown on Nano and machined (Machined) Ti surfaces and the endogenous BMP‐2/4 expression and the effect of BMP receptor BMPR1A silencing in both osteoblast differentiation and expression of genes related to TGF‐β/BMP signaling were evaluated. Nano supported higher BMP‐2 gene and protein expression and upregulated the osteoblast differentiation compared with Machined Ti surface. The BMPR1A silencing inhibited the osteogenic potential induced by Nano Ti surface as indicated by reduced alkaline phosphatase (ALP), osteocalcin and RUNX2 gene expression, RUNX2 protein expression and ALP activity. In addition, the expression of genes related to TGF‐β/BMP signaling was deeply affected by BMPR1A‐silenced cells grown on Nano Ti surface. In conclusion, we have demonstrated for the first time that nanotopography induces osteoblast differentiation, at least in part, by upregulating the endogenous production of BMP‐2 and modulating BMP signaling pathway. J. Cell. Biochem. 117: 1718–1726, 2016.

The effect of plasma-nitrided titanium surfaces on osteoblastic cell adhesion, proliferation, and differentiation

In this study, we evaluated the effect of new plasma-nitrided Ti surfaces on the progression of osteoblast cultures, including cell adhesion, proliferation and differentiation. Ti surfaces were treated using two plasma-nitriding protocols, hollow cathode for 3 h (HC 3 h) and 1 h (HC 1 h) and planar for 1 h. Untreated Ti surfaces were used as control. Cells derived from human alveolar and rat calvarial bones were cultured on Ti surfaces for periods of up to 14 days and the following parameters were evaluated: cell morphology, adhesion, spreading and proliferation, alkaline phosphatase (ALP) activity, extracellular matrix mineralization, and gene expression of key osteoblast markers. Plasma-nitriding treatments resulted in Ti surfaces with distinct physicochemical characteristics. The cell adhesion and ALP activity were higher on plasma-nitrided Ti surfaces compared with untreated one, whereas cell proliferation and extracellular matrix mineralization were not affected by the treatments. In addition, the plasma-nitrided Ti surfaces increased the ALP, reduced the osteocalcin and did not affect the Runx2 gene expression. We have shown that HC 3 h and planar Ti surfaces slightly favored the osteoblast differentiation process, and then these surfaces should be considered for further investigation using preclinical models.

Bone tissue response to plasma-nitrided titanium implant surfaces

A current goal of dental implant research is the development of titanium (Ti) surfaces to improve osseointegration. Plasma nitriding treatments generate surfaces that favor osteoblast differentiation, a key event to the process of osteogenesis. Based on this, it is possible to hypothesize that plasma-nitrided Ti implants may positively impact osseointegration. Objective The aim of this study was to evaluate the in vivo bone response to Ti surfaces modified by plasma-nitriding treatments. Material and Methods Surface treatments consisted of 20% N2 and 80% H2, 450°C and 1.5 mbar during 1 h for planar and 3 h for hollow cathode. Untreated surface was used as control. Ten implants of each surface were placed into rabbit tibiae and 6 weeks post-implantation they were harvested for histological and histomorphometric analyses. Results Bone formation was observed in contact with all implants without statistically significant differences among the evaluated surfaces in terms of bone-to-implant contact, bone area between threads, and bone area within the mirror area. Conclusion Our results indicate that plasma nitriding treatments generate Ti implants that induce similar bone response to the untreated ones. Thus, as these treatments improve the physico-chemical properties of Ti without affecting its biocompatibility, they could be combined with modifications that favor bone formation in order to develop new implant surfaces.

Clinical, Histological and Cellular Evaluation of Vertico-Lateral Maxillary Reconstruction Associating Alveolar Osteogenic Distraction and Fresh-Frozen Bone Allograft

T he rehabilitation of edentulous anterior maxillary defects with implant-supported prosthesis remains a challenge, since loss of teeth can lead to extensive vertical and horizontal bone resorption, compromising the aesthetical and functional results. Vertical alveolar defects higher than 5 mm are the most difficult to restore with high incidence of failure mainly due to either resorption or dehiscence. Several modalities of treatment have been proposed, such as autografts from distinct donor sites, allografts, xenografts, osteogenic distraction, and titanium meshes among others. Although autografts are considered the gold standard based on their osseoinduction, osseoconduction, and osteogenesis properties, some disadvantages like morbidity, time consuming and cost should be taken onto consideration before selecting this technique. In this context, alveolar osteogenic distraction (AOD) is a good alternative to gain both bone and soft tissue augmentation and fresh-frozen bone allograft (FFBA) has been successfully grafted to reconstruct bone defects in oral implantology. Beyond the unlimited availability, FFBA avoids the morbidity commonly associated with autograft harvesting. The selection of treatment should be based on adequate quality and amount of hard and soft tissues to get a suitable rehabilitation. U-shaped defects, usually present in the anterior maxilla area, are characterized by lack of structures that prevents initial soft tissue closure over a large bone graft. Considering that a tension-free closure must be performed to prevent incision breakdown on a large onlay bone graft, strategies to increase the soft tissue drape over a bone defect include free grafts, tissue expanders, and the use of gradual distraction of the residual bone. The purpose of this letter is to report a case presenting clinical, histological, and cellular evidences to support the combination of AOD and cortico-cancellous FFBA as a good alternative for reconstructing a vertico-lateral maxillary defect, allowing implant-supported rehabilitation.

Study comparing midazolam and nitrous oxide in dental anxiety control.

Abstract The purpose of this study is to comparatively assess the effect of midazolam and nitrous oxide associated with oxygen, in lower third molar extractions, on the change in the anxiety level of patients by salivary cortisol dosage. Twenty-eight male patients underwent lower third molar extraction under sedation with midazolam and nitrous oxide. Objective (salivary cortisol dosage) and subjective (Corah Dental Anxiety Scale) data have been obtained. By salivary cortisol, 40 minutes after midazolam administration, there has been a statistically significant difference compared with the mean baseline value. Midazolam was the most effective sedation method for reducing salivary cortisol level.

Participation of MicroRNA-34a and RANKL on bone repair induced by poly(vinylidene-trifluoroethylene)/barium titanate membrane

Abstract The poly(vinylidene-trifluoroethylene)/barium titanate (PVDF) membrane enhances in vitro osteoblast differentiation and in vivo bone repair. Here, we hypothesized that this higher bone repair could be also due to bone resorption inhibition mediated by a microRNA (miR)/RANKL circuit. To test our hypothesis, the large-scale miR expression of bone tissue grown on PVDF and polytetrafluoroethylene (PTFE) membranes was evaluated to identify potential RANKL-targeted miRs modulated by PVDF. The animal model used was rat calvarial defects implanted with either PVDF or PTFE. At 4 and 8 weeks, the bone tissue grown on membranes was submitted to a large-scale analysis of miRs by microarray. The expression of miR-34a and some of its targets, including RANKL, were evaluated by real-time polimerase chain reaction and osteoclast activity was detected by tartrate-resistant acid phosphatase (TRAP) staining. Among more than 250 miRs, twelve, including miR-34a, were simultaneously higher expressed (≥2 fold) at 4 and 8 weeks on PVDF. The higher expression of miR-34a was concomitant with a reduced expression of all its evaluated targets, including RANKL. Additionally, more TRAP-positive cells were observed in bone tissue grown on PTFE compared with PVDF in both time points. In conclusion, our results suggest that the higher bone formation induced by PVDF could be, at least in part, triggered by a miR-34a increase and RANKL decrease, which may inhibit osteoclast differentiation and activity, and bone resorption.

MicroRNA 665 Regulates Dentinogenesis through MicroRNA-Mediated Silencing and Epigenetic Mechanisms

ABSTRACT Studies of proteins involved in microRNA (miRNA) processing, maturation, and silencing have indicated the importance of miRNAs in skeletogenesis, but the specific miRNAs involved in this process are incompletely defined. Here, we identified miRNA 665 (miR-665) as a potential repressor of odontoblast maturation. Studies with cultured cell lines and primary embryonic cells showed that miR-665 represses the expression of early and late odontoblast marker genes and stage-specific proteases involved in dentin maturation. Notably, miR-665 directly targeted Dlx3 mRNA and decreased Dlx3 expression. Furthermore, RNA-induced silencing complex (RISC) immunoprecipitation and biotin-labeled miR-665 pulldown studies identified Kat6a as another potential target of miR-665. KAT6A interacted physically and functionally with RUNX2, activating tissue-specific promoter activity and prompting odontoblast differentiation. Overexpression of miR-665 reduced the recruitment of KAT6A to Dspp and Dmp1 promoters and prevented KAT6A-induced chromatin remodeling, repressing gene transcription. Taken together, our results provide novel molecular evidence that miR-665 functions in an miRNA-epigenetic regulatory network to control dentinogenesis.