Adriana Terezinha Neves Novellino Alves

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

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.

A randomized controlled clinical trial to evaluate a new xenograft for alveolar socket preservation

OBJECTIVE The aim of this clinical trial was to compare the effect of Bio-Oss(®) and a new bovine xenograft (Osseus(®) ) in alveolar sockets after a 24-week healing period. MATERIALS AND METHODS A total of 20 adult volunteers ages 30-60 were subjected to single tooth extraction. A tooth extraction was performed at the baseline. All sites were randomly allocated to two test groups (TG1: grafted using a new bovine xenograft, Osseus(®) , and TG2: grafted using commercially available bovine xenograft-Bio-Oss(®) ). Six months later, a sample of the grafted area was obtained and implants were inserted in the same site. Histological sections were examined focusing on the presence of fibrous connective tissue (CT), and newly formed bone in direct contact with the graft. The HE-stained sections were subjected to histomorphometrical evaluation using Image Pro-Plus(®) software (Release 7.0). The definitive crown was placed 3 months later. RESULTS Upon completion of the study, no patients were removed from the study and all inserted implants (10 in each group) were eventually integrated. After 6 months, in the TG1, the mean value of new bone formation was 33.7 (± 7.1), for CT was 32.3 (± 8.9) and for the remaining biomaterial was 10.7 (± 16.2). In the TG2, the mean value of new bone formation was 19.3 (± 22.6), of the CT was 49.9 (± 14.1) and of the remaining biomaterial was 22.6 (± 7.9). CONCLUSIONS No statistically significant difference was observed between TG1 and TG2 after 6 months (P > 0.05), and both biomaterials afforded a more favorable implant position.

In vitro and in vivo evaluation of strontium-containing nanostructured carbonated hydroxyapatite/sodium alginate for sinus lift in rabbits

Various synthetic bone substitutes have been developed to reconstruct bone defects. One of the most prevalent ceramics in bone treatment is hydroxyapatite (HA) that is a useful material as bone substitute, however, with a low rate of biodegradation. Its structure allows isomorphic cationic and anionic substitutions to be easily introduced, which can alter the crystallinity, morphology, biocompatibility, and osteoconductivity. The objective of this study was to investigate the in vitro and in vivo biological responses to strontium-containing nanostructured carbonated HA/sodium alginate (SrCHA) spheres (425<ϕ <600 μm) that were used for sinus lifts in rabbits using nanostructured carbonated HA/sodium alginate (CHA) as a reference. Cytocompatibility was determined using a multiparametric assay after exposing murine preosteoblasts to the extracts of these materials. Twelve male and female rabbits underwent bilateral sinus lift procedures and were divided into two groups (CHA or SrCHA) and in two experimental periods (4 and 12 weeks), for microscopic and histomorphometric analyses. The in vitro test revealed the overall viability of the cells exposed to the CHA and SrCHA extracts; thus, these extracts were considered cytocompatible, which was confirmed by three different parameters in the in vitro tests. The histological analysis showed chronic inflammation with a prevalence of macrophages around the CHA spheres after 4 weeks, and this inflammation decreased after 12 weeks. Bone formation was observed in both groups, and smaller quantities of SrCHA spheres were observed after 12 weeks, indicating greater bioresorption of SrCHA than CHA. SrCHA spheres are biocompatible and osteoconductive and undergo bioresorption earlier than CHA spheres.

Maxillary Ameloblastic Fibroma: A Case Report

Ameloblastic fibroma is a relatively rare benign odontogenic tumor in which both the epithelial and ectomesenchymal components are neoplastic. An 8-year-old Caucasian boy was referred to the dentist for evaluation of failed eruption of the maxillary left first molar. The panoramic radiograph showed a well-circumscribed unilocular radiolucency involving an unerupted maxillary left first permanent molar. The lesion was enucleated and the material was sent for histopathologic examination. Microscopically, it was composed by cords and islands of odontogenic epithelium in a myxoid cell-rich stroma that closely resemble the dental papilla with histopathological diagnosis of ameloblastic fibroma. After 24 months of follow-up no recurrence was observed and the maxillary left first molar erupted spontaneously through the buccal mucosa and was aligned with a fixed orthodontic appliance. This case emphasized the importance of careful differential diagnosis of intraosseous oral lesions and reported a rarity of the lesion and its atypical location.

Cytocompatibility and biocompatibility of nanostructured carbonated hydroxyapatite spheres for bone repair

ABSTRACT 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.

Carcinoma adenóide cístico: revisão da literatura e relato de caso clínico

The adenoid cystic carcinoma (ACC) is a malignant neoplasm of salivary gland that arises preferencially in parotid glands, submandibular and minor salivary glands, but is uncommon in sublingual glands. The ACC is a slow growth and infiltrative tumour that clinically is characterized by a firm mass. The present study aims to rewiew the atually literature of the ACC in relation of clinical and histopathological features and describes a case of ACC in submandibular gland.

Effectiveness and acceleration of bone repair in critical‐sized rat calvarial defects using low‐level laser therapy

Tissue regeneration remains a challenge for orthopedic and craniomaxillofacial surgery to treat bone loss. The use of low‐level laser therapy suggests a promise on this road with positive results for narrow defects. However, temporal and quantitative evaluations are required to understand the healing process of large injuries. The aim of this study was to investigate the repair of critical‐size bone defects in rat calvaria using a GaAlAs laser.

In Vivo Evaluation of Strontium-Containing Nanostructured Carbonated Hydroxyapatite

Bone tissue is a composite material that has hydroxyapatite (HA) as its main inorganic phase component. The biological apatites have low crystallinity and contain cationic and anionic substitutions in their structure, which differ from the available synthetic ceramics. The purpose of this study is to evaluate the biocompatibility of nanostructured carbonated hydroxyapatite microspheres containing 5 wt% strontium (SrcHA) compared with the biocompatibility of carbonated hydroxyapatite (cHA), both synthesized at 37°C and non-sintered, used to control stoichiometric HA microspheres in subcutaneous tissue of mice. The biomaterials (BM) were characterized using X-ray Diffraction (XRD), Vibrational Spectroscopy in an Infrared Fourier Transform (VSIRFT) and Scanning Electron Microscopy (SEM). Forty five balb-C mice were randomly divided into four groups of 15 animals each: SrcHA, cHA, HA, and without material implantation (Sham group). All samples were histologically processed for descriptive evaluation of the biological effect. At each experimental period (1, 3 and 9 weeks), there was a higher biosorption of the tested biomaterials observed in contrast with the HA. The cHA group was the only group completely phagocytosed by macrophages and giant cells after 9 weeks. All biomaterials proved to be biocompatible, and the cHA and SrcHA 3% groups exhibited a faster bioabsorption in comparison with the control group. The doping of strontium did not cause a greater biological response after the 3 experimental periods.

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

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.

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

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.