Bone-regenerative and biocompatible materials are indicated for the regeneration of bone lost in periodontology and maxillofacial surgery. Bio-Oss is a natural bone mineral for bone grafting of bovine origin and the most common used in this kind of interventions¹. Sil-Oss is a new synthetic nanostructured monetite-based material that is reabsorbed at the same time that is replaced by new bone tissue ². Bacterial infection is one of the complications related to this kind of material. Streptococcus oralis is the most associated oral infecting pathogen to oral surgery³ and Staphylococcus aureus is the most common infecting pathogen to maxillofacial non-oral interventions⁴. Here we evaluated bacterial adherence of two of the most common infecting bacteria of this kind of biomaterial: S. oralis and S. aureus, on Bio-Oss and Sil-Oss.

S. oralis ATCC 9811 and S. aureus 15981 strains were used. Bacterial adherence was evaluated using the modified previously described protocol of Kinnari et al.⁵ that was adapted to our biomaterial. The quantification was performed by the drop plate method⁶. The statistical data were analyzed by pairwise comparisons using the nonparametric Mann-Whitney test with a level of statistical significance of p<0.05. Values are cited and represented as medians.

Bacterial adherence decreased significantly on Sil-Oss compared to Bio-Oss. S. oralis ATCC 9811 adherence was between 11 and 13-fold less on Sil-Oss compared to Bio-oss. In the case of S. aureus15981, the adherence was between 4 and 6-fold less on Sil-Oss compared to Bio-Oss.

Sil-Oss nanostructured monetite-based biomaterial could be considered as a promising biomaterial to be used for the regeneration of bone defects since the bacterial adherence on it is lower than on another currently used material.

Summary

Attachment, proliferation and osteogenic maturation of hMSCs are enhanced on a sub-micron grooved Ti6Al4V alloy, while osteoblasts are less sensitive. These effects are attributed to their different maturation stage and may be mediated through differential activation of the RhoA/ROCK pathway.

Objectives

To determine the limits of spinal displacement before the onset of neurophysiological changes during spinal surgery. Assessing if the type of force applied or the section of the adjacent nerve roots increases the tolerance to displacement.

Introduction: In this work a bioactive glass-ceramic (GC) in the system SiO2-CaO-P2O5 was evaluated as bone substitute biomaterial. In this sense, the capacity of mesenchymal stem cells (MSCs) to adhere, proliferate and differentiate into osteoblast (OBs) with or without GC was investigated. Two types of culture medium, i.e. growth medium (GM) and osteogenic medium (OM), were evaluated.

Materials and Methods: The GC was obtained by heat treatment of a bioactive glass obtained by the sol-gel method. Isolation and culture of MSCs: The adult MSCs were isolated from bone marrow of adult rabbits obtained by direct aspirations of ileac crest. Isolation and culture of OBs: The OBs used as control were obtained by enzymatic digestion. Behavior of MSCs on GC: For the study of the behavior of isolated MSCs on the GC, two series of 96-well plates were seeded, one plate with GM and the other one with OM. The number of cells was evaluated through the XTT assay. OC production and CD90 expression of cells cultured in both media were measured to evaluate the differentiation of MSCs into OBs. Statistical analysis: A variance analysis (ANOVA) was carried out.

Results: The number of cells growing in OM and GM, there were no significant differences between them. The MSCs under the conditions of this study expressed an osteoblastic phenotype (OC production, decrease CD90 expression, mineralized extracell matrix). These two effects took place by either the action of exposing the MSCs to a MO and by the effect of the GC.

Introduction: Osteoarthritis is the most common joint disease in the world. Biochemical and genetic factors as well as mechanical stress contribute to lesions in the cartilage. The present study analyses the effect of b-Endorphin on the cells of articular cartilage.

Materials and methods: We used rat articular cartilage for the study. After tripsinizing the cartilage and isolating the chondrocytes the cells were cultured in a culture medium. B-Endorphin was dissolved in the culture medium at concentrations of 1 and 10 mM. Only the culture medium was added to the control wells. Naloxone 1 mM was added for co-treatment with b-Endorphin and naloxone. Thirty minutes later, b-Endorphin was added, thus blocking its receptors.

Results: We studied the effect of this procedure on chondrocytes’ proliferating activity and on the proteoglycan synthesis of the extracellular matrix. An increase was observed in the incorporation of 3H-Thymidine, which in turn reflected an increase in the chondrocytes’ proliferating activity. In addition, 35S incorporation analyses were made of cultures which assessed proteoglycan synthesis which showed an increase in the extracellular-matrix forming activity. Differences between the groups with b-endorphin, b-endorphin + naloxone and the control group were found to be highly significant (p< 0.01).

Conclusions: B-endorphin has a stimulating effect upon chondrocytes and proteoglycans present in the extracellular matrix in culture. These stimulating effects are mediated by the interaction with a specific opioid receptor, present in the articular cartilage cells. It may be conceived that trophic stimulation of cartilage cells in the early stages of the disease might partly mitigate the loss of joint surface.

Introduction and Objectives: The aim of this study is to evaluate the results of the technique described by Ahlgren and Larsson in 1989, presenting our experience with 7 patients.

Materials and Methods: A retrospective study was conducted on the clinical records of 7 adolescents treated in our center beginning in 1991 using the technique described by Ahlgren and Larsson. There were 3 males and 4 females, ranging in age from 13 to 16.5 years (average: 14 years 10 months). All subjects had a history of repeated ankle sprains for 2 to 5 years before surgery. In all cases there was painful instability of the ankle which significantly limited physical activity. In 4 cases, symptoms were present even when walking on level ground. On clinical examination, 3 cases showed significant instability under varus stress, 3 others had moderate instability, and one case had mild instability. Surgical technique was similar in all cases and involved creating a periosteal flap with a distal anterior base, including the fibulotalar and fibulocalcaneal ligaments, which was sutured with tension to the fibula. In 3 cases, this was done with the help of Mitek metal hooks. In 5 of 7 cases, an ossicle of the fibular malleolus visible on the radiographs was removed. Duration of surgery ranged from 30 to 60 minutes, with a mean of 40 minutes. Postoperative immobilisation consisted of a plaster cast used for an average of 45 days, after which time patients progressively returned to normal physical activities. Patients were advised to use an ankle brace. Average follow-up time was 35 months, with a range of 13 to 72 months.

Results: In 5 patients, a subjective improvement in ankle stability was found on examination. Only in one case was there a significant reduction in radiographic instability when the tibiotalar joint was moved from 20° to 8°. One patient developed a superficial infection of the surgical wound which resolved with antibiotic treatment. Two patients suffered sprains within the first year after intervention, but there were no further sprains, and the injuries did not seem to affect the final outcome. However, the outcome of one of these was considered to be only fair due to occasional mild pain which did not limit physical activity. Two cases had poor outcomes due to frequent pain which limited physical activity postoperatively for 2 and 6 years, respectively. However, neither patient had repeat sprains during this period. The remaining 4 cases were considered to have had good results, as the patients were totally asymptomatic and without any limitation of physical activity.

Discussion and Conclusions: This simple, non-aggressive method is an attractive option for use in adolescents. We therefore conclude that more studies are needed to validate its effectiveness.