Américo Afonso

Granules of osteopatite and glass-reinforced hydroxyapatite implanted in rabbit tibiae

Granules of a modified hydroxyapatite, glass-reinforced hydroxyapatite composite and commercial hydroxyapatite were implanted in rabbit tibiae. Histological studies were carried out after 1 and 2 months implantation periods using light and fluorescence microscopy. A much higher percentage of bone contact was developed for both the glass-reinforced hydroxyapatite composite and the modified hydroxyapatite when compared to commercial hydroxyapatite (89–91% versus 66%) after 2 months implantation. The mechanism of bone formation and growth around implants is discussed in terms of the influence of elements incorporated into these novel materials which are commonly found in bone tissues, such as Na, K and Mg, and the presence of a soluble β-tricalcium phosphate phase in the microstructure of the composite.

Characterization and preliminary in vivo evaluation of a novel modified hydroxyapatite produced by extrusion and spheronization techniques

A glass-reinforced hydroxyapatite (HA) composite, recently registered as Bonelike®, was developed for bone grafting. This biomaterial is composed of a modified HA matrix with α- and β-tricalcium phosphate secondary phases and ionic species that mimic the chemical composition of human bone. Several in vitro and in vivo studies have confirmed the benefits of these properties. However, these studies were all executed with Bonelike® polygonal granules obtained by crushing. In this study, Bonelike® pellets were produced through a patented process, which required the use of techniques such as extrusion and spheronization. The final product presented a homogeneous size, a 55.1% global porosity and a spherical shape. This spherical shape permitted a better adaptation to the implantation site and improved injectability. Additionally, it also may contribute to formation of macropores as pellets packaging leaves open spaces. After implantation of Bonelike® polygonal granules and Bonelike® pellets in monocortical defects in sheep for 8 and 12 weeks, light microscopy and scanning electron microscopy showed extensive osteointegration simultaneously with bone regeneration for both presentations. Histomorphometric analysis did not reveal statistically significant differences between defects treated with Bonelike® polygonal granules and Bonelike® pellets, which suggests similar in vivo performances.

The consequences of orofacial trauma resulting from violence: a study in Porto

Orofacial injuries resulting from violence are a fairly common event. In Portugal, however, the impact of these injuries remains to be elucidated. This study aims to analyze the injuries and permanent consequences of orofacial trauma (in a three-dimensional perspective: organic, functional and situational), resulting from violence. To do so, a retrospective analysis of all violence-related forensic reports performed in the North Branch of the National Institute of Legal Medicine, during 2007, was carried out (n = 513). It was found that most victims were men with a mean age of 35.4 (SD = 15.1). Most aggressions were due to punches and/or kicks. The most frequent orofacial injuries were lip injuries (57.7%), followed by extra-oral soft tissue injuries (35.9%), gingival and oral mucosa injuries (29.2%), and teeth and/or periodontal injuries (17.5%). The most frequent long-term consequences concerned the teeth and periodontal area (14.0%), followed by the lip area (7.4%), and gingival and oral mucosa tissues (3.9%). In terms of the effect on functions and life situations, it was found that chewing and embarrassment in social life events were the most prevalent (43.6% and 83.6%, respectively). These results showed that orofacial trauma from violence-related events can damage a persons quality of life, especially those concerning the teeth area, as a result of their implications in normal function and in life situations.

Oral injuries in victims involving intimate partner violence

INTRODUCTION Current literature states that dental medicine can have an important role in diagnosing situations of domestic violence, namely cases of intimate partner violence, since many of the injuries that occur in this context concern the head and neck areas. The aim of this study was to characterize oral injuries in these cases in a Portuguese population, and to determine the kind of permanent consequences that they might represent. MATERIAL AND METHODS 332 forensic reports of domestic violence survivors were analysed. The reports concerned examinations performed in the North Branch of the National Institute of Legal Medicine of Portugal in 2007. Reports were assessed in order to obtain data regarding victim and offender demographic characteristics, and to characterize the nature and number of sustained injuries and their permanent consequences. MAIN RESULTS Most victims were females with a mean age of 33.7 years; the most frequent offender was the spouse; the majority of oral injuries affected soft tissues; permanent body consequences were found mainly in the teeth and periodontal tissues; permanent functional consequences were described as chewing difficulties, feeling pain or soft tissue mobility changes; permanent consequences for life activities referred mostly to social life aspects. CONCLUSIONS Oral injuries and their consequences were observed in 13.4% of intimate partner violence cases, and though being suggestive of this kind of violence, oral injuries alone are insufficient to identify this kind of abuse, and additional diagnostic criteria and evidence should be used.

Biological Behaviour of Bonelike® Graft Implanted in the Tibia of Humans

This paper reports the ability of Bonelike® to regenerate bone defected areas when implanted in the tibia of 3 patients (average age of 59 years) during a high tibial osteotomy (HTO) to treat medial compartment osteoarthritis of the knee. Bonelike® is a synthetic bone graft designed to mimic the inorganic composition of bone using a patent process that consists of liquid sintering hydroxyapatite in the presence of CaO-P2O5 based glass. The preliminary clinical evaluation performed showed that an intimate contact between new formed bone and Bonelike® was established (67±10 %), with no fibrous interface. Therefore, Bonelike® is a single-handedly viable osteoconductive synthetic grafting material as it has been demonstrated from the profiles of radiological, histological and scanning electron microscopy analyses for the six months implantation period.

Morphology effect of bioglass-reinforced hydroxyapatite (Bonelike(®) ) on osteoregeneration.

In the last decades, the well-known disadvantages of autografts and allografts have driven to the development of synthetic bone grafts for bone regeneration. Bonelike(®) , a glass-reinforced hydroxyapatite (HA) composite was developed and registered for bone grafting. This biomaterial is composed by a modified HA matrix, with α- and β-tricalcium phosphate secondary phases. Aiming to improve the biological characteristics of Bonelike(®) , new spherical pelleted granules, of different shape and size, were developed with controlled micro and macrostructure. In the present study, it was compared the physicochemical properties and in vivo performance of different Bonelike(®) granule presentations-Bonelike(®) polygonal (500-1000 µm size) and Bonelike spherical (250-500 µm; 500-1000 µm size). For the in vivo study, Bonelike(®) was implanted on sheep femurs, with various implantation times (30 days, 60 days, 120 days, and 180 days). X-ray diffraction analysis revealed that the phase composition of different granules presentations was similar. Bonelike(®) spherical 500-1000 µm was the most porous material (global porosity and intraporosity) and Bonelike(®) polygonal 500-1000 µm the less porous. Considering the in vivo study, both polygonal and spherical granules presented osteoconductive proprieties. The spherical granules showed several advantages, including easier medical application through syringe and improved osteointegration, osteoconduction, and degradation, by the presence of larger pores, controlled micro- and macrosctructure and suitable particle format that adapts to bone growth. Bonelike(®) spherical 500-1000 µm showed improved new bone invasion throughout the materials structure and Bonelike(®) spherical 250-500 µm appeared to induce faster bone regeneration, presenting less unfilled areas and less lacunae in the histological analysis.

Evaluation of implant osseointegration with different regeneration techniques in the treatment of bone defects around implants: an experimental study in a rabbit model

AIM The aim of this study was to evaluate the osseointegration of implants placed in areas with artificially created bone defects, using three bone regeneration techniques. MATERIAL AND METHODS The experimental model was the rabbit femur (16), where bone defects were created and implants were placed. The peri-implant bone defects were filled with a deproteinized bovine bone mineral, NuOss™ (N), NuOss™ combined with plasma rich in growth factors (PRGF) (N+PRGF), NuOss™ covered by an RCM(6) membrane (N+M), or remained unfilled (control group [C]). After 4 and 8 weeks, the animals were euthanized and bone tissue blocks with the implants and the surrounding bone tissue were removed and processed according to a histological protocol for hard tissues on non-decalcified ground sections. The samples were studied by light and electron scanning microscopy, histometric analysis was performed to assess the percentage of bone in direct contact with the implant surface and a statistical analysis of the results was performed. RESULTS In the samples analyzed 4 weeks after implantation, the percentage of bone tissue in direct contact with the implant surface for the four groups were 57.66±24.39% (N), 58.62±20.37% (N+PRGF), 70.82±20.34 % (N+M) and 33.07±5.49% (C). In the samples with 8 weeks of implantation time, the percentage of bone in direct contact was 63.35±27.69% (N), 58.42±24.77% (N+PRGF), 78.02±15.13% (N+M) and 40.28±27.32% (C). In terms of the percentage of bone contact, groups N and N+M presented statistically significant differences from group C in the 4-week trial test (P<0.05; ANOVA). For the 8-week results, only group N+M showed statistically significant differences when compared with group C (P<0.05; ANOVA). CONCLUSION In conclusion, the NuOss™ granules/RCM(6) membrane combination presented a percentage of bone contact with the implant surface statistically greater than in the other groups.

The in vivo performance of an alkali-free bioactive glass for bone grafting, FastOs(®) BG, assessed with an ovine model.

Although bioactive glasses are successfully used as bone substitutes, recent studies have revealed that the high alkali content in these glasses leads to fast in vivo degradation rates that may not match the rate of new bone ingrowth. This prompted us to design and develop novel bioactive glasses that are devoid of alkali but still demonstrate high bioactivity in vitro. This article describes the in vivo performance of an alkali-free bioactive glass with the following composition (Wt %): 13.03 MgO-33.98 CaO-13.37 P2 O5 -38.84 SiO2 -0.77 CaF2 (labelled as FastOs® BG). An animal model was used to assess the in vivo performance of FastOs® BG, using 45S5 Bioglass® as control. The evaluation was performed through implantation of FastOs® BG and 45S5 Bioglass® , during one month, in femoral bone defects in sheep. Subcutaneous implantation of both glasses was also performed in order to assess tissue response through a standardized method. Histological and scanning electron microscopy assessment of retrieved subcutaneous and bone samples demonstrated that FastOs® BG is biocompatible, osteoconductive, that it can be osteointegrated, and that it is more slowly resorbed than 45S5 Bioglass® . These features suggest that FastOs® BG is a potential candidate for bone grafting.

Prevalência das anomalias de número numa população portuguesa. Estudo radiográfico

Resumo Introducao As anomalias de numero da denticao influenciam o equilibrio do sistema estomatognatico, facto que torna pertinente o conhecimento da sua prevalencia. Em Portugal sao escassos os estudos relativos a este assunto. Objectivo Este estudo teve como objectivo a determinacao da prevalencia de anomalias de numero na denticao de uma populacao portuguesa, atraves da analise de radiografias panorâmicas de pacientes que frequentaram a clinica da Faculdade de Medicina Dentaria da Universidade do Porto (FMDUP) e, posteriormente, a comparacao dos resultados obtidos, com os dados anteriormente publicados. Resultados Obteve-se uma prevalencia de agenesias dentarias, na denticao definitiva, de 12,23%, incluindo os 3.°s molares, e de 6,47% se excluirmos estes dentes. Relativamente aos dentes supranumerarios a prevalencia encontrada foi de 0,72% em ambas as denticoes. Conclusoes Os resultados obtidos neste estudo estao de acordo com os anteriormente descritos para a populacao portuguesa, excepto no que diz respeito a localizacao e predominio sexual dos dentes supranumerarios.

GUIDED BONE REGENERATION USING OSTEOPATITE GRANULES AND POLYTETRAFLUOROETHYLENE MEMBRANES

Granules of a modified hydroxyapatite, Osteopatite®, were implanted in the right posterior tibiae of adult rabbits. We studied the extent of bone regeneration in bone holes. In the right tibiae, that were filled with granules of this biomaterial covered with a polytetrafluoro-ethylene (PTFE) membrane using, as a control, uncovered granules. In the left tibia, an empty hole was covered with PTFE membrane and a second hole was left empty to be used as a control. A histomorphometric study was carried out using light microscopy, four and eight weeks after the surgery. The covered granules presented a higher percentage of bone contact than the uncovered ones, and it was also possible to observe a better bone tissue organization, mainly produced by the immobilization action of the PTFE membrane. Empty bone defects covered with PTFE membranes, two months after implantation, presented large areas of Haversian bone and direct bone contact to the PTFE membrane.