RESUMO
OBJECTIVE: Fresh-frozen bone allograft (FFBA) is an alternative to autogenous bone (AB) for reconstructing maxillary bone. Despite the promising clinical results, cell responses to FFBA and AB were not evaluated. Thus, our aim was to compare cells harvested from maxillary reconstructed sites with either AB or FFBA in terms of osteoblast differentiation and to evaluate the effect of culturing cells in contact with FFBA. METHODS: Cells harvested from three patients submitted to bilateral maxillary reconstruction with AB and FFBA were cultured to evaluate: proliferation, alkaline phosphatase activity, extracellular matrix mineralization and gene expression of osteoblastic markers. The effect of FFBA on osteoblast differentiation was studied by culturing cells harvested from AB in contact with FFBA and evaluating the same parameters. Data were compared using either two-way ANOVA followed by Tukey-b test or Student's t test (p≤0.05). RESULTS: Cell proliferation was higher in cultures from AB grafted sites and extracellular matrix mineralization was higher in cultures derived from FFBA grafted sites. The gene expression of alkaline phosphatase, RUNX2, bone sialoprotein and osteocalcin was higher in cells derived from FFBA compared with cells from AB grafted sites. However, the exposure of cells derived from AB to FFBA particles did not have any remarkable effect on osteoblast differentiation. CONCLUSIONS: These results indicate the higher osteogenic activity of cells derived from FFBA compared with AB reconstructed sites, offering an explanation at cellular level of why FFBA could be a suitable alternative to AB for reconstructing maxillary bone defects.
Assuntos
Transplante Ósseo/métodos , Criopreservação , Reconstrução Mandibular/métodos , Fosfatase Alcalina/biossíntese , Aloenxertos/transplante , Regeneração Óssea/genética , Transplante Ósseo/efeitos adversos , Diferenciação Celular/fisiologia , Proliferação de Células/fisiologia , Células Cultivadas , Feminino , Humanos , Pessoa de Meia-Idade , Osteoblastos/citologia , Osteoblastos/fisiologia , Osteocalcina/biossínteseRESUMO
OBJECTIVES: Autografts from mandibular symphysis and ramus are often used for bone reconstruction. Based on this, we hypothesized that these sites could be useful cell sources for bone tissue engineering approaches. Thus, our study aimed at evaluating the proliferation and osteoblast phenotype development of cells derived from mandibular symphysis and ramus. MATERIALS AND METHODS: Cells were isolated from bone fragments of four patients by enzymatic digestion and cultured under osteogenic condition for up to 17 days. Cultures were assayed for cell proliferation, gene expression of key bone markers runt-related transcription factor 2 (Runx2), distal-less homeobox 5 (DLX5), SATB homeobox 2 (SATB2), Osterix (OSX), family with sequence similarity 20, member C (FAM20C), bone sialoprotein (BSP), osteopontin (OPN) and osteocalcin (OC), alkaline phosphatase (ALP) expression and activity, and extracellular matrix mineralization. Data were compared by two-way ANOVA or t-test for independent samples when appropriate. RESULTS: Cells derived from ramus displayed lower proliferative activity and higher gene expression of Runx2, DLX5, SATB2, OSX, FAM20C, BSP, OPN and OC, ALP protein expression and activity and extracellular matrix mineralization compared with symphysis-derived cells. CONCLUSION: Symphysis and ramus may be considered as cell sources for bone tissue engineering approaches but due to the higher osteogenic potential, ramus-derived cells are more appealing for constructing cell-based biomaterials.
Assuntos
Osso e Ossos , Mandíbula/citologia , Osteoblastos/citologia , Engenharia Tecidual/métodos , Proliferação de Células , Células Cultivadas , Humanos , Osteoblastos/transplante , Osteogênese/genética , FenótipoRESUMO
Cephalometry has been used to measure hard and soft facial tissues, as well as the pharyngeal air space for the diagnosis of obstructive sleep apnea (OSA). The changes occurring in the pharynx due to maxillo-mandibular advancement (MMA) have not been established or quantified. The objective of this study was to identify the anatomical changes of the pharynx and of hard tissues that occur in patients with OSA after MMA. 19 patients with a polysomnographic diagnosis of OSA were submitted to cephalometric analysis before and 6 months after surgery in order to evaluate the changes produced by MMA in the pharynx and soft tissues. Cephalometry was standardized in order to obtain descriptive measurements of the dimensions of the airways, the position of the hyoid bone, and maxilla-mandibular relations. The modifications of the pharynx due to MMA showed a significant relation obtained by cephalometry. For each millimeter of maxillary and mandibular bone advancement there was a 0.76mm increase in the retropalatal region and a 1.2mm increase in the pharynx in the retrolingual region. In addition, MMA promoted a significant repositioning of the hyoid bone in the cranial direction.
Assuntos
Cefalometria/métodos , Avanço Mandibular/métodos , Maxila/cirurgia , Faringe/patologia , Apneia Obstrutiva do Sono/cirurgia , Queixo/patologia , Feminino , Seguimentos , Humanos , Osso Hioide/patologia , Masculino , Mandíbula/patologia , Mandíbula/cirurgia , Maxila/patologia , Osso Nasal/patologia , Osteotomia de Le Fort/métodos , Osteotomia Sagital do Ramo Mandibular/métodos , Palato/patologia , Polissonografia , Sela Túrcica/patologia , Base do Crânio/patologiaRESUMO
The aim of this study was to determine the biocompatibility and osteoconductive potential of a high-strength canasite glass ceramic. Glass-ceramic rods were produced using the lost-wax casting technique and implanted in the mid-shafts rabbit femurs. Implants were harvested at 4, 13 and 22 weeks and prepared for light and electron microscopy. Hydroxyapatite was used as a control material. Hydroxyapatite implants were surrounded by new mineralised bone tissue after 4 weeks of implantation. The amount of bone surrounding the implant increased slightly at 13 weeks. In contrast, canasite glass and glass ceramic implants were almost entirely surrounded by soft tissue during all the time periods. Close contact between bone and canasite glass-ceramic implant without the intervening fibrous tissue was observed in only a few regions. The canasite formulation evaluated was not osteoconductive and appeared to degrade in the biological environment. It was therefore concluded that the canasite formulation used was unsuitable for use as implant. Further work is required to improve the biocompatibility of these materials with bone tissue. It is possible that this could be achieved by reducing the solubility of the glass and glass ceramic.
Assuntos
Materiais Biocompatíveis , Cerâmica , Fêmur/metabolismo , Vidro , Implantes Experimentais , Animais , Durapatita/química , Durapatita/metabolismo , Fêmur/citologia , Teste de Materiais , Microscopia Eletrônica de Varredura , Osseointegração/fisiologia , Osteogênese/fisiologia , CoelhosRESUMO
The effectiveness of lidocaine and benzocaine in reducing pain produced by needle insertion into the palate was evaluated in a double-blind and placebo-controlled study using a more suitable method. Twenty subjects, 10 men and 10 women, submitted to 4 sessions in which they were randomly treated with 5% lidocaine, a placebo that tasted like lidocaine, 20% benzocaine, and a placebo that tasted like benzocaine. At each session, a 27-gauge needle was inserted into the palate twice, once before (baseline) and once after drug application for 1 minute. Immediately after each insertion, subjects indicated on a visual analog scale the pain intensity perceived. Lidocaine and benzocaine were equally efficient, and both were better than placebo in reducing pain caused by insertion of needles into the palate.