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Relationship between the surface energy and the histologic results of different titanium surfaces.

The aim of this study was to evaluate, through in vitro and in vivo studies, the existence of a relationship between surface energy, for wettability, and the clinical behavior of dental implants with different surfaces, one with a surface treated by sandblasting with titanium oxide microparticles followed by acid-etching treatment (experimental group) and another with a machined surface (control group). For the in vitro tests, a total of 30 titanium disks (15 disks for each group) were evaluated by scanning electron microscopy and dispersive energy spectroscopy and for surface roughness and wettability. For the in vivo tests, a total of 24 implants (12 implants for each group) were inserted in the tibiae of 6 rabbits and were removed after 30 and 60 days for histologic analysis. The results showed that the implants with the experimental surface presented a low wettability, and it also resulted in highly stimulated new bone formation in vivo, when compared with the control group dental implant. As for the bone formation, differences between the different surfaces seemed evident, both in quantity and in quality, as implants from the experimental group showed a higher new bone deposition than that from the control group. Thus, in vitro and in vivo tests demonstrated an excellent biologic response of the surfaces treated by sandblasting with microparticles of titanium oxide followed by acid etching

Three-dimensional tomographic mapping related to primary stability and structural miniscrew characteristics

OBJECTIVES: To evaluate the maxilla, mandible, and cortical plates on computerized tomographic (CT) scans to achieve accurate three-dimensional bone thickness measurements. SETTING AND SAMPLE POPULATION: We selected the CT scans of 25 subjects (among 102), aged 18-58 years (10 men, 15 women), with nearly complete dentition. MATERIAL AND METHODS: We performed interradicular and bucco-lingual (including cortical plate thickness) measurements in dental areas distal to the canines in both alveolar arches, at three levels (5, 8, and 11 mm) from the alveolar ridge. RESULTS: The mean thicknesses of the cortical plates in the maxilla were 1.10 mm buccally and 1.27 mm on the palatal side (p < 0.05). In the mandible, cortical plates were 2.23 mm buccally and 2.02 mm lingually. Mandibular buccal and lingual cortical plates became thicker distally in the second and third molar areas. There was considerable variation in cortical thickness (from 0.25 to 5.50 mm). Based on interradicular distances, only 13% of measured sites in the maxilla were suitable for miniscrew insertion ( 653.3 mm), but 63% of sites were suitable in the mandible. CONCLUSION: This study showed considerable individual variation in bone thickness. Our data suggested that the palatal/lingual side may provide greater primary stability for miniscrews. The palatal area, between the second upper bicuspid and the first molar, appeared to be the most suitable area for tapered 7- to 9-mm miniscrews, starting at 1.5-2 mm from the alveolar crest

Ultrasonic versus drills implant site preparation: a histologic analysis in bovine ribs.

Ultrasonic surgery is a recently developed system for cutting bone with microvibrations. The aim of the current study was a histologic comparison between conventional drills versus ultrasonic surgery devices in implant bed preparation.Ten bovine ribs were used, and a total of 100 perforations were randomly performed: half (n = 50) (group A) of the perforations were done through conventional drills using a single cylindrical bur (Bone System, Milan, Italy), 13 mm in height and 2 mm in width at a speed of 400 rpm, and the other half (n = 50) (group B) using an ultrasonic device (Surgysonic; Esacrom, Imola Italy), mounted with a diamond-coated cylindrical tip. After implant sites' preparation, the ribs were immediately stored in 10\% buffered formalin and processed to obtain thin ground sections.At higher magnification, microcracks at the interface were detected. In group A, they were numerous and showed a thickness and depth ranging from 20 to 120 \u3bcm and from 500 to 1000 \u3bcm, respectively. In group B, very few or no microcracks were present. Statistically significant differences were found in the microcracks density in the cortical bone but not in the cancellous bone.The findings from this study suggest that ultrasonic implant site preparation showed a higher performance in terms of accuracy and uniformity of the osteotomy cut, compared with conventional rotary instruments. Further studies should be conducted to understand whether a smooth, congruent implant bed able to retain fine bone structures may affect the early phases of bone healing and therefore improve osseointegration

Hemostasis control in dental extractions in patients receiving oral anticoagulant therapy: an approach with calcium sulfate.

The aim of this study was to evaluate the use of calcium sulfate (CaS) as a hemostatic agent after tooth extraction in patients with anticoagulant drug therapy. A total of 30 patients undergoing anticoagulant therapy (22 women and 8 men) with a mean age of 54.6 years (SD = 9.2 years), needing dental extractions, were selected for this study. They were divided into 2 groups, control (group 1) and test (group 2), in a randomized way. In group 1 patients, the postextraction socket was managed with obliterative suture only. Group 2 patients were treated with CaS placed into the postextraction sockets. All the patients did not interrupt the anticoagulant therapy during the dental treatment. The healing pattern was found to be approximately similar in all treatment groups, showing significant improvement at each consecutive visit. However, a statistically significant difference in the adequate hemostasis was evident between groups 1 and 2 (P = 0.0056). The use of CaS helped to control the bleeding from inside the socket, producing instantly a very good hemostasis. Further studies are necessary to confirm the simplicity, possibilities, and limits of the proposed procedure

Atrophic jaw reconstruction by means of calvarial bone graft: Long-term results

The aim of this work was to investigate the immunohistochemical and histologic patterns occurring in samples obtained from sites reconstructed with calvarial bone graft, 4 months (T1) and 10 years (T2) after grafting, in comparison to those observed in samples from the calvaria taken from the donor sites at the moment of withdrawal for the grafting (T0).Samples underwent immunohistochemical analysis for bone sialoprotein, matrix metalloproteinases 2 and 9, vascular endothelial growth factor, and Bax expressions; terminal-deoxynucleotidyl-transferase-mediated dUTP nick end-labeling analysis to evaluate the number of apoptotic samples; and morphologic evaluation after hematoxylin and eosin staining.The expression levels of all the investigated molecules, such as the apoptotic cells' count, showed a significant (P andlt; 0.05) increase in T1 samples, that is, 4 months after grafting, although their expression levels recorded after 10 years seemed to be comparable to those in the native bone. Moreover, at observation under the light microscope, T1 samples showed a nonuniform morphology, with mineralized areas surrounded by connective tissues where blood vessels could be distinguished. On the other hand, T0 and T2 samples showed a similar aspect, characterized by uniform areas of mineralized extracellular matrix with cavities containing osteocytes.These data suggest that, after approximately 4 months, it is possible to highlight stronger remodeling phenomena, accompanied by new bone formation and new blood vessel proliferation, which are necessary to the host tissue for graft integration. On the contrary, these phenomena could not be observed in samples obtained after a long period (T2), which reveal a morphologic and an immunohistochemical pattern comparable to that recorded in calvarial native bone (T0). © 2010 by Mutaz B. Habal, MD

A comparison of bovine bone and hydroxyapatite scaffolds during initial bone regeneration: an in vitro evaluation.

OBJECTIVES: To evaluate the different behavior of 3-dimensional biomaterial scaffolds-Bovine Bone (BB; Bio-Oss) and Hydroxyapatite (HA; ENGIpore)-during initial bone healing and development. MATERIALS AND METHODS: Human dental papilla stem cells (hDPaSCs) were selected with FACsorter cytofluorimetric analysis, cultured with osteogenic medium, and analyzed with Alizarin red stained after differentiation. The obtained osteoblast-like cells (OCs) were cultured with BB and HA. alkaline phosphatase (ALP), OC, MEPE, and runt-related transcription factor 2 (RUNX2) expression markers were investigated performing Western blot and reverse transcription-polymerase chain reaction (RT-PCR) analysis. After 40 days, samples were analyzed by light and electron microscopy. RESULTS: All the samples showed high in vitro biocompatibility and qualitative differences of OCs adhesion. RT-PCR and Western blot data exhibited similar marker rate, but ALP, OC, MEPE, and RUNX2expression, during initial healing and bone regeneration phase, was higher and faster in human dental papilla onto BB than in HA scaffolds. In biomaterials growth, RUNX2 seems to play an important role as a key regulator in human OCs from dental papilla bone development. CONCLUSION: Different surface BB scaffold characteristics seem to play a critical role in OCs differentiation showing different time of bone regeneration morphological characteristics as well as higher and faster levels of all observed markers