Cinética de crecimiento in vitro de osteoblastos humanos sobre cerámica porosa de hidroxiapatita

Pilot Study Using a Chitosan-Hydroxyapatite Implant for Guided Alveolar Bone Growth in Patients with Chronic Periodontitis

Periodontitis is an infectious and inflammatory disease associated with significant loss of alveolar crest and soft tissue attached to the teeth. Chitosan and hydroxyapatite are biomaterials used for bone tissue repair because of their biodegradability and biocompatibility in nature. The present study evaluated the effects of chitosan (CH) in combination with hydroxyapatite (HAP) to promote alveolar bone growth. A chitosan implant mixed with hydroxyapatite was implanted into the affected area of 9 patients suffering chronic periodontitis. Patients were evaluated through X-ray images and a millimetric slide over a one year period. The application of CH/HAP produced an average alveolar bone growth of 5.77 mm (±1.87 mm). At the onset of the study, the dental pocket exhibited a depth level (DPDL) of 8.66 mm and decreased to 3.55 mm one year after the implant. Tooth mobility grade was 2.44 mm at the onset and 0.8 mm at the end of the study with a significant difference of p < 0.001. Moreover, the bone density in the affected areas was similar to the density of the bone adjacent to it. This result was confirmed with the software implant viewer from Anne Solutions Company. In conclusion, the CH/HAP implant promoted alveolar bone growth in periodontitis patients.

[Ceramic 55S as a substrate for the regeneration of bone defects; an in vitro study]

INTRODUCTION

The purpose of this work is to evaluate the in vitro behaviour and the capacity to induce osteoblastic differentiation of a 55S vitro-ceramic (Vc) on a population of adult rabbit mesenchymal stem-cells (MSCs).

MATERIAL AND METHODS

The material was obtained using the sol-gel method. The cells were obtained from rabbit bone-marrow aspirate and seeded over the Vc, and over plastic (control). The MSCs were cultivated in two culture media; one a standard DMEM (growth medium), and the other an osteoblastic phenotype inducer, composed of DMEM complemented with dexamethasone, ß-glycerophosphate and ascorbic acid-2-phosphate (osteogenic medium). The morphology of the cells that grew was assessed using a scanning electronic microscope. The tetrazolium salt reduction test was used for evaluating the cell growth. For cell differentiation, osteocalcin production and loss of CD90 bone surface antigen, characteristic of MSCs, were quantified.

RESULTS

During the culture time the MSCs adhered, proliferated and formed a mineralised extracellular matrix over the Vc. An osteoblastic phenotype finally being shown, producing osteocalcin and decreasing the expression of the CD90 antigen, regardless of the culture medium used.

CONCLUSION

Based on these results we can state that Vc 55S behaved like a material capable of supporting adhesion and growth of MSCs and, in turn, inducing the differentiation of the MSCs to osteoblastic cell lines, thus showing osteoconduction and osteoinduction properties.

In vitro behaviour of adult mesenchymal stem cells seeded on a bioactive glass ceramic in the SiO(2)-CaO-P(2)O(5) system

This work describes the evaluation of a glass ceramic (55S41C4P-1300) as a potential substrate for bone tissue engineering. For that purpose, the capacity of mesenchymal stem cells (MSCs), isolated from rabbit bone marrow, to adhere, proliferate and differentiate into osteoblast (OBs) with or without 55S41C4P-1300 was investigated. Two types of culture medium, i.e. growth medium (GM) and osteogenic medium (OM), were evaluated. The bioactive 55S41C4P-1300, containing pseudowollastonite, wollastonite, tricalcium phosphate and crystoballite as crystalline phases, was obtained by heat treatment of a sol-gel glass (55SiO(2), 41CaO, 4P(2)O(5) (mol.%)) at 1300 degrees C. The results showed that the MSCs adhered, spread, proliferated and produced mineralized extracellular matrix on 55S41C4P-1300 regardless of the culture medium used. As the same time, they showed an osteoblastic phenotype, and this phenomenon was accompanied by the gradual diminution of the marker CD90 expression. The 55S41C4P-1300 was able to induce the differentiation of MSCs into OBs in the same way as OM without glass ceramic. This effect increased with the combination of 55S41C4P-1300 with OM. The glass ceramic evaluated in this work is bioactive, cytocompatible and capable of promoting the differentiation of MSCs into OBs. For that reason, it could be regarded as a suitable matrix in tissue engineering for bone tissue regeneration.