Publications by authors named "Suelen Cristina Sartoretto"

20 Publications

  • Page 1 of 1

Osseodensification enables bone healing chambers with improved low-density bone site primary stability: an in vivo study.

Sci Rep 2021 Jul 29;11(1):15436. Epub 2021 Jul 29.

Clinical Research Laboratory, Dentistry School, Universidade Federal Fluminense, Rua Mario Santos Braga, 28/4 Floor, Niterói, RJ, Brazil.

Primary implant stability is a prerequisite for successful implant osseointegration. The osseodensification technique (OD) is a non-subtractive drilling technique that preserves the bone tissue, increases osteotomy wall density, and improves the primary stability. This study aimed to investigate the hypothesis that OD, through a wider osteotomy, produces healing chambers (HCs) at the implant-bone interface without impacting low-density bone primary stability. Twenty implants (3.5 × 10 mm) with a nanohydroxyapatite (nHA) surface were inserted in the ilium of ten sheep. Implant beds were prepared as follows: (i) 2.7-mm-wide using subtractive conventional drilling (SCD) technique (n = 10); (ii) 3.8-mm-wide using an OD bur system (n = 10). The sheep were randomized to two groups, with samples collected at either 14-(n = 5) or 28-days (n = 5) post-surgery and processed for histological and histomorphometric evaluation of bone-implant contact (BIC) and bone area fraction occupancy (BAFO). No significant group differences were found with respect to final insertion torque and implant stability quotient (p > 0.050). BIC values were higher for SCD after 14 and 28 days (p < 0.050); however, BAFO values were similar (p > 0.050). It was possible to conclude that the OD technique allowed a wider implant bed preparation without prejudice on primary stability and bone remodeling.
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http://dx.doi.org/10.1038/s41598-021-94886-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8322171PMC
July 2021

Clinical efficacy of simvastatin gel combined with polypropylene membrane on the healing of extraction sockets: A triple-blind, randomized clinical trial.

Clin Oral Implants Res 2021 Jun 27;32(6):711-720. Epub 2021 Mar 27.

Department of Dental Technics, School of Dentistry, Fluminense Federal University, Niterói, Brazil.

Objectives: This study aimed to evaluate dimensional changes, level of soft tissue healing, and pain/discomfort perception in post-extraction sockets filling with 1.2% simvastatin (SIM) gel covered with polypropylene membranes (PPPM).

Material And Methods: Twenty-six post-extraction sockets of posterior teeth were randomly allocated in two groups: (a) socket filling with 1.2% SIM gel and covered with PPPM (n = 13) and (b) socket filling with placebo gel and covered with PPPM (n = 13). Cone-beam computed tomography (CBCT) images before and 90 days after the extraction enabled alveolar bone dimensional changes calculation using horizontal and vertical measurements. The measurements occurred at three different levels for thickness located 1, 3, and 5 mm from the top of the bone crest. The vertical (depth) measure was assessed from the most apical portion of the socket to the bone crest's most coronal portion. Seven days after the extractions, the level of soft tissue healing and pain perception were also analyzed.

Results: After 90 days of extractions, the dimensional changes in thickness in the test group were significantly smaller in sections A (p = .044), B (p = .036) and C (p = .048) when compared to the control group. The test group showed a significantly lower height-dimensional change than the control group (p < .0001). Soft tissue healing index (p = .63), perception of pain (p = .23), and number of analgesics consumed (p = .25) were similar between groups.

Conclusions: Simvastatin at 1.2% compared with placebo effectively reduced the dimensional changes in post-extraction sockets covered with PPPM. There was no significant difference in the level of soft tissue healing and postoperative pain between the test and control groups.
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http://dx.doi.org/10.1111/clr.13740DOI Listing
June 2021

In Vivo Comparative Evaluation of Biocompatibility and Biodegradation of Bovine and Porcine Collagen Membranes.

Membranes (Basel) 2020 Dec 15;10(12). Epub 2020 Dec 15.

Clinical Research Laboratory in Dentistry, Universidade Federal Fluminense, Niteroi 24020-140, RJ, Brazil.

Mechanical barriers prevent the invasion of the surrounding soft tissues within the bone defects. This concept is known as Guided Bone Regeneration (GBR). The knowledge about the local tissue reaction and the time of degradation of absorbable membranes favors the correct clinical indication. This study aimed to evaluate the biocompatibility and biodegradation of a bovine collagen membrane (Lyostypt, São Gonçalo, Brazil) and compare it to a porcine collagen membrane (Bio-Gide) implanted in the subcutaneous tissue of mice, following ISO 10993-6:2016. Thirty Balb-C mice were randomly divided into three experimental groups, LT (Lyostypt), BG (Bio-Gide), and Sham (without implantation), and subdivided according to the experimental periods (7, 21, and 63 days). The BG was considered non-irritant at seven days and slight and moderate irritant at 21 and 63 days, respectively. The LT presented a small irritant reaction at seven days, a mild reaction after 21, and a reduction in the inflammatory response at 63 days. The biodegradation of the LT occurred more rapidly compared to the BG after 63 days. This study concluded that both membranes were considered biocompatible since their tissue reactions were compatible with the physiological inflammatory process; however, the Bio-Gide was less degraded during the experimental periods, favoring the guided bone regeneration process.
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http://dx.doi.org/10.3390/membranes10120423DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7765348PMC
December 2020

Nanostructured Carbonated Hydroxyapatite Associated to rhBMP-2 Improves Bone Repair in Rat Calvaria.

J Funct Biomater 2020 Dec 4;11(4). Epub 2020 Dec 4.

Oral Surgery Department, Dentistry School, Universidade Federal Fluminense, Rio de Janeiro 24020-140, Brazil.

Many biomaterials are used for Bone Morphogenetic Proteins (BMPs) delivery in bone tissue engineering. The BMP carrier system's primary function is to hold these growth factors at the wound's site for a prolonged time and provide initial support for cells to attach and elaborate the extracellular matrix for bone regeneration. This study aimed to evaluate the nanostructured carbonated hydroxyapatite microspheres (nCHA) as an rhBMP-2 carrier on rats calvaria. A total of fifteen male Wistar rats were randomly divided into three groups ( = 5): clot (control group), rhBMP-2 associated with collagen membrane (COL/rhBMP-2) or associated with the microspheres (nCHA/rhBMP-2). After 45 days, the calvaria defect samples were evaluated through histological, histomorphometric, and SR-µCT analyses to investigate new-formed bone and connective tissue volume densities. The descriptive histological analysis showed that nCHA/rhBMP-2 improved bone formation compared to other groups. These results were confirmed by histomorphometric and SR-µCT analysis that showed substantially defect area filling with a higher percentage of newly formed (36.24 ± 6.68) bone than those with the COL/rhBMP-2 (0.42 ± 0.40) and Clot (3.84 ± 4.57) ( < 0.05). The results showed that nCHA is an effective carrier for rhBMP-2 encouraging bone healing and an efficient alternative to collagen membrane for rhBMP-2 delivery.
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http://dx.doi.org/10.3390/jfb11040087DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7768361PMC
December 2020

Atrophic Maxilla Rehabilitation Through Dental Implants Using the V-4 Strategy Associated With Guided Surgery: A Case Report and Technique Description.

J Oral Implantol 2020 Dec 3. Epub 2020 Dec 3.

Veiga de Almeida University.

Atrophic maxilla rehabilitation through dental implants is always a challenging procedure. However, alternative approaches such as guided surgery and the installation of short implants are progressively supplanting more invasive bone regeneration procedures. A V-4 technique described in 2016 facilitates the installation of dental implants in patients with atrophic maxilla; however, its authors recommend incision, flap opening, and elevation of the anterior area of the maxillary sinuses. This case report describes a less invasive proposal for modifying the technique through the association of guided surgery, which improves implant placement accuracy, shortens surgical time, and reduces morbidity.
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http://dx.doi.org/10.1563/aaid-joi-D-20-00121DOI Listing
December 2020

The Influence of Nanostructured Hydroxyapatite Surface in the Early Stages of Osseointegration: A Multiparameter Animal Study in Low-Density Bone.

Int J Nanomedicine 2020 10;15:8803-8817. Epub 2020 Nov 10.

Clinical Research Laboratory, Dentistry School, Universidade Federal Fluminense, Niteroi, RJ, Brazil.

Background And Objective: The success rates of dental implants in low-density bone have been reported as a challenge, especially for early or immediate loading in the maxilla posterior area. Nanoscale architecture affects the roughness, surface area, surface energy of the implant and can enhance osseointegration. This study aimed to evaluate the implant-surface topography and biomechanical, histomorphometric, and histological bone responses to a new nanostructured hydroxyapatite surface placed in the iliac crest of sheep.

Methods: Ten female sheep (2-4 years) received 30 implants (n=10/group): HAnano coated (Epikut Plus, S.I.N. Implant System, Sao Paulo, SP, Brazil), SLActive (BLX, Straumann, Basel, Switzerland), and TiUnite (NobelActive, Nobel Biocare, Göteborg, Sweden) surfaces. Scanning electron microscopy with energy-dispersive spectroscopy evaluated the implant surface topography, the insertion torque value, and resonance frequency analysis evaluated the primary stability, bone-implant contact, and bone-area fraction occupancy were evaluated after 14 and 28 days after implant placement.

Results: The surface morphology was considerably comparable between the implant groups'; however, the TiUnite group presented a remarkable different surface. The SLActive and TiUnite groups presented an insertion torque average of 74 (±8.9) N/cm that was similar to that of HAnano 72 (±8.3) N/cm (p >0.05). The resonance frequency evaluated with Osstell/SmartPeg or Penguin/MulTipeg showed similar results when assessing implants from the same group. BIC and BAFO significantly increased (p<0.05) throughout the experimental periods to all groups, but BIC and BAFO values were similar among the implants at the same time point. After 4 weeks, bone-implant contact was higher than 80% of the total length analyzed. New bone occupies around 60% of analyzed area around the implants.

Conclusion: HAnano coated surface promoted comparable osseointegration as SLActive and TiUnite in the sheep model. The three tested surfaces showed comparable osseointegration at the early stages of low-density bone repair in the sheep model.
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http://dx.doi.org/10.2147/IJN.S280957DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7667590PMC
December 2020

Is THP-1 viability affected by the crystallinity of nanostructured carbonated hydroxyapatites?

J Biomed Mater Res A 2021 07 28;109(7):1266-1274. Epub 2020 Oct 28.

Bioengineering Laboratory, National Institute of Metrology, Quality and Technology, Duque de Caxias, Brazil.

In daily clinical practice, there is a notable variety of synthetic bone substitute, with various resorption rates, different chemical and structural characteristics that influence on bone regeneration and are not suitable for every clinical use. New biomaterials based on nanotechnology have been developed to be bioabsorbable as new bone is formed. This study intends to evaluate THP-1 cell viability when exposed to extracts of unsintered nanostructured carbonated hydroxyapatite (cHA) microspheres processed at 5 and 37°C compared to sintered hydroxyapatite processed at 90°C. cHA shows, in previous studies, biocompatibility, and better bioabsorption rates, consequently, improve the deposition of new bone and tissue repair. The results demonstrated that the tested biomaterials did not activate inflammatory role through THP-1 cells and did not affect activated macrophages independently of their crystallinities, suggesting their safety and biocompatibility. These results are of fundamental importance for the advancement of research on smart materials, especially in what controls the effect of nanostructured cHA microspheres in the biological environment, seems to be a promising biomaterial in clinical application on regenerative medicine.
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http://dx.doi.org/10.1002/jbm.a.37120DOI Listing
July 2021

Effectiveness of connective tissue graft substitutes for the treatment of gingival recessions compared with coronally advanced flap: a network meta-analysis.

Clin Oral Investig 2020 Oct 26;24(10):3395-3406. Epub 2020 Aug 26.

Department of Periodontology and Oral Implantology, Dental Research Division, University of Guarulhos, São Paulo, Brazil.

Objectives: This study aimed to conduct a network comparison of the clinical effect of connective tissue graft (CTG) substitutes on the treatment of gingival recessions using coronally advanced flap.

Materials And Methods: An electronic search without language or dates restrictions was performed in five databases and in Grey literature for articles published until May, 2020. The eligibility criteria comprised randomized controlled trials (RCTs) that analyzed the clinical outcomes of CTG substitutes when compared with coronally advanced flap (CAF) for the treatment of Miller class I and II (Cairo RT I) gingival recessions. A pairwise and network meta-analysis were conducted for each periodontal parameters to assess and compare the outcomes among different treatment arms for the primary and secondary outcomes. This systematic review (SR) was registered in INPLASY under number INPLASY202060075.

Results: Twenty-seven studies were included in the present SR. All analyzed CTG substitutes showed superior results when comparing with CAF alone for all periodontal parameters. However, when compared in a network, the acellular dermal matrix (ADM) demonstrated the best treatment ranking of probability results, followed by platelet-rich fibrin (PRF), enamel matrix derivative (EMD), and xenogeneic collagen matrix (XCM) for root coverage (RC).

Conclusion: This SR observed that the association of biomaterials increases the effectiveness of RC in comparison with CAF alone. Based on the treatment ranking, although all the biomaterials analyzed showed a positive effect for RC, the ADM demonstrated the best results.

Clinical Relevance: To know the effectiveness of CTG substitutes for the treatment of gingival recessions.
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http://dx.doi.org/10.1007/s00784-020-03547-3DOI Listing
October 2020

Ineffectiveness of ozone therapy in nonsurgical periodontal treatment: a systematic review and metaanalysis of randomized clinical trials.

Clin Oral Investig 2020 Jun 12;24(6):1877-1888. Epub 2020 May 12.

Department of Dental Technics, School of Dentistry, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil.

Objective: This systematic review (SR) aimed at assessing the adjunctive clinical effect of ozone therapy (OT) on nonsurgical periodontal treatment.

Materials And Methods: Articles published prior to September 2019 were electronically searched in four databases without any other date or language restrictions and manually searched in regular journals and in gray literature. This review was performed according to the PICO format. The eligibility criteria comprised randomized controlled trials (RCTs) that analyzed the adjunctive effect of OT on nonsurgical periodontal treatment.

Results: Twelve studies published between 2010 and 2019 were included in this SR. A metaanalysis of ten reports showed that there was no statistically significant difference in the periodontal parameters analyzed when scaling and root planing (SRP) plus sulcus irrigation with ozonated water or sulcus insertion of ozonated gas were used when compared to SRP alone. Additionally, there was no significant difference when the effect of SRP plus ozonated water was compared with SRP plus 2% chlorhexidine gluconate (CLX). No studies reported significant microbiological differences when the use of ozone was compared with SRP alone.

Conclusions: The results of this SR do not support the use of OT for nonsurgical periodontal treatment. However, due to the potential heterogeneity across the studies, the presence of confounding factors, and the short follow-up of some included RCTs, these results should not be considered definitive.

Clinical Relevance: The current evidence indicates that ozone has antimicrobial activity and good biocompatibility with periodontal cells and gingival fibroblasts. However, no evidence was found for a positive effect of OT as an adjunct to scaling and root planing.
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http://dx.doi.org/10.1007/s00784-020-03289-2DOI Listing
June 2020

Alveolar bone repair with strontium- containing nanostructured carbonated hydroxyapatite.

J Appl Oral Sci 2018 Jan 18;26:e20170084. Epub 2018 Jan 18.

Universidade Federal Fluminense, Faculdade de Odontologia, Laboratório Associado de Pesquisa Clínica em Odontologia, Niterói, RJ, Brasil.

This study aimed to evaluate bone repair in rat dental sockets after implanting nanostructured carbonated hydroxyapatite/sodium alginate (CHA) and nanostructured carbonated hydroxyapatite/sodium alginate containing 5% strontium microspheres (SrCHA) as bone substitute materials. Twenty male Wistar rats were randomly divided into two experimental groups: CHA and SrCHA (n=5/period/group). After one and 6 weeks of extraction of the right maxillary central incisor and biomaterial implantation, 5 μm bone blocks were obtained for histomorphometric evaluation. The parameters evaluated were remaining biomaterial, loose connective tissue and newly formed bone in a standard area. Statistical analysis was performed by Mann-Withney and and Wilcoxon tests at 95% level of significance. The histomorphometric results showed that the microspheres showed similar fragmentation and bio-absorbation (p>0.05). We observed the formation of new bones in both groups during the same experimental periods; however, the new bone formation differed significantly between the weeks 1 and 6 (p=0.0039) in both groups. The CHA and SrCHA biomaterials were biocompatible, osteoconductive and bioabsorbable, indicating their great potential for clinical use as bone substitutes.
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http://dx.doi.org/10.1590/1678-7757-2017-0084DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5777423PMC
January 2018

Accelerated Healing Period with Hydrophilic Implant Placed in Sheep Tibia.

Braz Dent J 2017 Sep-Oct;28(5):559-565

Department of Oral Surgery, UFF - Universidade Federal Fluminense, Niterói, RJ, Brazil.

The objective of this study was to evaluate the early osseointegration of two different implants surfaces, a sandblasted and acid-etched surface (TN) compared with same geometry and surface roughness modified to be hydrophilic/wettable by conditioning in an isotonic solution of 0.9% sodium-chloride (TA) through histological and histomorphometric analysis after sheep tibia implantation. Forty dental implants, divided in two groups (TN and TA) were placed in the left tibia of twenty healthy, skeletally mature Santa Ines sheep (n=5/experimental period). After 7, 14, 21 and 28 days post-implantation, the samples were removed and the sheep were kept alive. Analysis of resin sections (30 μm) allowed the quantification of bone area (BA) and bone-to-implant contact (BIC). TA group presented nearly 50% increase in BA at 14 days (p<0.001, ANOVA - Tukey's post test) compared with 7 days. The TA presented higher values than the TN for BA and BIC at 14, 21, and 28 days after placement, stabilizing bone healing. TA hydrophilic surface promoted early osseointegration at 14 and 21 days compared to TN, accelerating bone healing period post-implant placement in sheep tibia.
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http://dx.doi.org/10.1590/0103-6440201601559DOI Listing
August 2018

The Pull-Through Technique: A Viable Option for Preserving the Inferior Alveolar Nerve during Surgical Resection.

Craniomaxillofac Trauma Reconstr 2017 Dec 11;10(4):329-331. Epub 2016 Nov 11.

Department of Oral Surgery, Dentistry School, Fluminense Federal University, Rio de Janeiro, Brazil.

The aim of this study was to present a new surgical technique used to remove benign mandibular tumors with minimal damage to the inferior alveolar nerve. The pull-through technique was shown using an ameloblastoma surgical resection as an example. This technique consisted in the reconstruction of the lower jaw associating the resection of the lesion with nerve repair at the same surgical time. The resection was performed using the pull-through technique and the inferior alveolar nerve was preserved. After 6 months, the patient presented a recovery of approximately 80% of sensory function. The surgical technique presented should be considered an important method by which to produce a higher functional outcome to remove benign mandibular tumors with minimal damage to the inferior alveolar nerve and allows the maintenance of quality of life for the patient, as the consequences of this type of surgery are minimized.
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http://dx.doi.org/10.1055/s-0036-1593893DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5669983PMC
December 2017

Randomized clinical trial for the biological evaluation of two nanostructured biphasic calcium phosphate biomaterials as a bone substitute.

Clin Implant Dent Relat Res 2017 Oct 13;19(5):802-811. Epub 2017 Jul 13.

Dental Clinical Research Center, Oral Surgery Department, Dentistry School, Fluminense Federal University, Niteroi, Rio de Janeiro, Brazil.

Background: The presence of nonresorbable residual granules of hydroxyapatite (HA) may decrease the bone/implant interface. To balance resorption and bone formation biphasic calcium phosphate ceramics compounds applied at different rates have been studied.

Purpose: The aim of this trial was to compare the clinical, histological, and histomorphometric responses of two new biphasic calcium phosphate biomaterials in fresh dental sockets after 3 and 6 months.

Materials And Methods: Forty-eight volunteers were divided randomly and double-blindly into 4 groups of 12 individuals: Clot (C), BoneCeramic (BC), Biomaterial 1 (B1), and Biomaterial 2 (B2) groups. Three and six months later, samples were obtained, and histological and histomorphometric sections were evaluated, focusing on the presence of fibrous connective tissue (CT) and newly formed bone. Statistical analysis was performed (P < .05%).

Results: The quantification of crystalline phases showed B1 composed of HA (60.28%) and β-TCP (39.72%); B2 composed of HA (78.21%) and β-TCP (21.79%); and BC composed of HA (61%) and β-TCP (39%). The B1 group showed the most newly formed bone (69.3% ± 6.03%), followed by the BC (51.6 ± 12.34%), B2 (46.6 ± 7.66%), and C groups (45.4 ± 7.98%), and less connective tissue and biomaterial remained in the B1 group after 6 months.

Conclusion: B1 group showed the greatest amount of newly formed bone after 6 months.
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http://dx.doi.org/10.1111/cid.12516DOI Listing
October 2017

SHEEP AS AN EXPERIMENTAL MODEL FOR BIOMATERIAL IMPLANT EVALUATION.

Acta Ortop Bras 2016 Sep-Oct;24(5):262-266

. Universidade Federal Fluminense, Faculdade de Odontologia, Programa de Pós-Graduação em Odontologia, Niterói, RJ, Brazil.

Objective: Based on a literature review and on our own experience, this study proposes sheep as an experimental model to evaluate the bioactive capacity of bone substitute biomaterials, dental implant systems and orthopedics devices. The literature review covered relevant databases available on the Internet from 1990 until to date, and was supplemented by our own experience.

Methods: For its resemblance in size and weight to humans, sheep are quite suitable for use as an experimental model. However, information about their utility as an experimental model is limited. The different stages involving sheep experiments were discussed, including the care during breeding and maintenance of the animals obtaining specimens for laboratory processing, and highlighting the unnecessary euthanasia of animals at the end of study, in accordance to the guidelines of the 3Rs Program.

Results: All experiments have been completed without any complications regarding the animals and allowed us to evaluate hypotheses and explain their mechanisms.

Conclusion: The sheep is an excellent animal model for evaluation of biomaterial for bone regeneration and dental implant osseointegration. From an ethical point of view, one sheep allows for up to 12 implants per animal, permitting to keep them alive at the end of the experiments. Level of Evidence II, Retrospective Study.
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http://dx.doi.org/10.1590/1413-785220162405161949DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5266658PMC
February 2017

Physico-chemical and Histomorphometric Evaluation of Zinc-containing Hydroxyapatite in Rabbits Calvaria.

Braz Dent J 2016 Oct-Dec;27(6):717-726

Department of Oral Surgery, Dental School, UFF - Universidade Federal Fluminense, Niterói, RJ, Brazil.

The aim of this study was to characterize the physico-chemical properties and bone repair after implantation of zinc-containing nanostructured porous hydroxyapatite scaffold (nZnHA) in rabbits' calvaria. nZnHA powder containing 2% wt/wt zinc and stoichiometric nanostructured porous hydroxyapatite (nHA - control group) were shaped into disc (8 mm) and calcined at 550 °C. Two surgical defects were created in the calvaria of six rabbits (nZnHA and nHA). After 12 weeks, the animals were euthanized and the grafted area was removed, fixed in 10% formalin with 0.1 M phosphate buffered saline and embedded in paraffin (n=10) for histomorphometric evaluation. In addition, one sample from each group (n=2) was embedded in methylmethacrylate for the SEM and EDS analyses. The thermal treatment transformed the nZnHA disc into a biphasic implant composed of Zn-containing HA and Zn-containing β-tricalcium phosphate (ZnHA/βZnTCP). The XRD patterns for the nHA disc were highly crystalline compared to the ZnHA disc. Histological analysis revealed that both materials were biologically compatible and promoted osteoconduction. X-ray fluorescence and MEV-EDS of nZnHA confirmed zinc in the samples. Histomorphometric evaluation revealed the presence of new bone formation in both frameworks but without statistically significant differences (p>0.05), based on the Wilcoxon test. The current study confirmed that both biomaterials improve bone repair, are biocompatible and osteoconductive, and that zinc (2wt%) did not increase the bone repair. Additional in vivo studies are required to investigate the effect of doping hydroxyapatite with a higher Zn concentration.
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http://dx.doi.org/10.1590/0103-6440201601028DOI Listing
April 2017

Histomorphometric evaluation of strontium-containing nanostructured hydroxyapatite as bone substitute in sheep.

Braz Oral Res 2016 6;30(1):e45. Epub 2016 May 6.

Department of Oral Surgery, School of Dentistry, Universidade Federal Fluminense, Niterói, RJ, Brazil.

The aim of this study is to evaluate the biocompatibility and osteoconductivity in surgical defects of sheep tibias filled with 1% strontium-containing nanostructured hydroxyapatite microspheres (SrHA), stoichiometric hydroxyapatite without strontium microspheres (HA), or blood clots. Santa Ines sheep were subjected to three perforations on the medial side of the left tibia. The biomaterials were characterized by X-ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) before implantation and by X-Ray Microfluorescence (µFRX) and Scanning Electron Microscopy (SEM) after sheep tibias implantation. Surgical defects were filled with blood clots (control), SrHA (Group 1) or HA (Group 2). After 30 days, 5-µm bone blocks were obtained for histological evaluation, and the blocks obtained from 1 animal were embedded in methylmethacrylate for undecalcified sections. Mononuclear inflammatory infiltrate remained mild in all experimental groups. Giant cells were observed surrounding biomaterials particles of both groups and areas of bone formation were detected in close contact with biomaterials. All groups showed newly formed bone from the periphery to the center of the defects, which the control, HA and SrHA presented 36.4% (± 21.8), 31.2% (± 14.7) and 26.2% (± 12.9) of newly formed bone density, respectively, not presenting statistical differences. In addition, the connective tissue density did not show any significant between groups. The SrHA showing a higher volume density of biomaterial (51.2 ± 14.1) present in the defect compared to HA (32.6 ± 8.5) after 30 days (p = 0.03). Microspheres containing 1% SrHA or HA can be considered biocompatible, have osteoconductive properties and may be useful biomaterials for clinical applications.
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http://dx.doi.org/10.1590/1807-3107BOR-2016.vol30.0045DOI Listing
December 2016

Cytocompatibility and biocompatibility of nanostructured carbonated hydroxyapatite spheres for bone repair.

J Appl Oral Sci 2015 Nov-Dec;23(6):599-608

Departamento de Biologia Celular e Molecular, Instituto de Biologia, Universidade Federal Fluminense, Niteroi, RJ, Brazil.

Objective: The aim of this study was to investigate the in vitro and in vivo biological responses to nanostructured carbonated hydroxyapatite/calcium alginate (CHA) microspheres used for alveolar bone repair, compared to sintered hydroxyapatite (HA).

Material And Methods: The maxillary central incisors of 45 Wistar rats were extracted, and the dental sockets were filled with HA, CHA, and blood clot (control group) (n=5/period/group). After 7, 21 and 42 days, the samples of bone with the biomaterials were obtained for histological and histomorphometric analysis, and the plasma levels of RANKL and OPG were determined via immunoassay. Statistical analysis was performed by Two-Way ANOVA with post-hoc Tukey test at 95% level of significance.

Results: The CHA and HA microspheres were cytocompatible with both human and murine cells on an in vitro assay. Histological analysis showed the time-dependent increase of newly formed bone in control group characterized by an intense osteoblast activity. In HA and CHA groups, the presence of a slight granulation reaction around the spheres was observed after seven days, which was reduced by the 42nd day. A considerable amount of newly formed bone was observed surrounding the CHA spheres and the biomaterials particles at 42-day time point compared with HA. Histomorphometric analysis showed a significant increase of newly formed bone in CHA group compared with HA after 21 and 42 days from surgery, moreover, CHA showed almost 2-fold greater biosorption than HA at 42 days (two-way ANOVA, p<0.05) indicating greater biosorption. An increase in the RANKL/OPG ratio was observed in the CHA group on the 7th day.

Conclusion: CHA spheres were osteoconductive and presented earlier biosorption, inducing early increases in the levels of proteins involved in resorption.
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http://dx.doi.org/10.1590/1678-775720150122DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4716697PMC
July 2016

Early osseointegration driven by the surface chemistry and wettability of dental implants.

J Appl Oral Sci 2015 May-Jun;23(3):279-87

Dental Clinical Research Center, Dentistry School, Fluminense Federal University, Nitero, Rio de Janeiro, Brazil.

Objective: The objective of this study was to investigate the impact of two different commercially available dental implants on osseointegration. The surfaces were sandblasting and acid etching (Group 1) and sandblasting and acid etching, then maintained in an isotonic solution of 0.9% sodium chloride (Group 2).

Material And Methods: X-ray photoelectron spectroscopy (XPS) was employed for surface chemistry analysis. Surface morphology and topography was investigated by scanning electron microscopy (SEM) and confocal microscopy (CM), respectively. Contact angle analysis (CAA) was employed for wetting evaluation. Bone-implant-contact (BIC) and bone area fraction occupied (BAFO) analysis were performed on thin sections (30 μm) 14 and 28 days after the installation of 10 implants from each group (n=20) in rabbits' tibias. Statistical analysis was performed by ANOVA at the 95% level of significance considering implantation time and implant surface as independent variables.

Results: Group 2 showed 3-fold less carbon on the surface and a markedly enhanced hydrophilicity compared to Group 1 but a similar surface roughness (p>0.05). BIC and BAFO levels in Group 2 at 14 days were similar to those in Group 1 at 28 days. After 28 days of installation, BIC and BAFO measurements of Group 2 were approximately 1.5-fold greater than in Group 1 (p<0.05).

Conclusion: The surface chemistry and wettability implants of Group 2 accelerate osseointegration and increase the area of the bone-to-implant interface when compared to those of Group 1.
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http://dx.doi.org/10.1590/1678-775720140483DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4510662PMC
November 2015

Maxillary Sinus Augmentation with a New Xenograft: A Randomized Controlled Clinical Trial.

Clin Implant Dent Relat Res 2015 Oct 23;17 Suppl 2:e586-93. Epub 2014 Dec 23.

Dentistry School, Fluminense Federal University, Niteroi, RJ, Brazil.

Background: Insufficient residual alveolar bone height is a common deterrent in the placement of dental implants in the posterior maxilla. The use of autografts, xenografts, allografts and alloplasts or a combination between them has been demonstrated to be effective for increasing bone height and bone volume in the deficient posterior maxilla.

Purpose: The aim of this clinical trial is to comparatively determine the density of newly formed in sinus floor augmentation bone after a 24-week healing period treatment with a new bovine xenograft.

Materials And Methods: The sinus floor was grafted with Bio-Oss® (n = 10) and Osseous® (n = 10). Histological sections were examined with a focus on the presence of connective tissue (CT) and newly formed bone (NFB). The sections were histomorphometrically evaluated and the definitive crown was inserted after 3 months.

Results: After 6 months, the mean value of new bone formation was 24.60 (±2.503), the CT was 42.60 (±4.006) and the remaining biomaterial was 25.40 (±2.547) in Bio-Oss group. In Osseous group, the mean value of new bone formation was 24.90 (±3.542), the CT was 45.70 (±7.040) and the remaining biomaterial was 22.90 (±3.247).

Conclusions: Both biomaterials afforded a favorable implant position and the prosthetic rehabilitation.
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http://dx.doi.org/10.1111/cid.12289DOI Listing
October 2015

Cellular behavior as a dynamic field for exploring bone bioengineering: a closer look at cell-biomaterial interface.

Arch Biochem Biophys 2014 Nov 27;561:88-98. Epub 2014 Jun 27.

Laboratório de Bioensaios e Dinâmica Celular, Depto. Química e Bioquímica, Instituto de Biociência, Universidade Estadual Paulista, UNESP, Campus Botucatu, Botucatu, SP, Brazil. Electronic address:

Bone is a highly dynamic and specialized tissue, capable of regenerating itself spontaneously when afflicted by minor injuries. Nevertheless, when major lesions occur, it becomes necessary to use biomaterials, which are not only able to endure the cellular proliferation and migration, but also to substitute the original tissue or integrate itself to it. With the life expectancy growth, regenerative medicine has been gaining constant attention in the reconstructive field of dentistry and orthopedy. Focusing on broadening the therapeutic possibilities for the regeneration of injured organs, the development of biomaterials allied with the applicability of gene therapy and bone bioengineering has been receiving vast attention over the recent years. The progress of cellular and molecular biology techniques gave way to new-guided therapy possibilities. Supported by multidisciplinary activities, tissue engineering combines the interaction of physicists, chemists, biologists, engineers, biotechnologist, dentists and physicians with common goals: the search for materials that could promote and lead cell activity. A well-oriented combining of scaffolds, promoting factors, cells, together with gene therapy advances may open new avenues to bone healing in the near future. In this review, our target was to write a report bringing overall concepts on tissue bioengineering, with a special attention to decisive biological parameters for the development of biomaterials, as well as to discuss known intracellular signal transduction as a new manner to be explored within this field, aiming to predict in vitro the quality of the host cell/material and thus contributing with the development of regenerative medicine.
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http://dx.doi.org/10.1016/j.abb.2014.06.019DOI Listing
November 2014
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