Early bone healing around implant surfaces treated with variations in the resorbable blasting media method. A study in rabbits

Objective: this study aimed to histomorphologically and histomorphometrically evaluate the in vivo response to three variations in the resorbable blasting media (RBM) surface processing in a rabbit femur model. Study Design: screw root form implants with 3.75 mm in diameter by 8 mm in length presenting four surfaces (n=8 each): alumina-blasted/acid-etched (AB/AE), bioresorbable ceramic blasted (TCP), TCP + acid etching, and AB/AE + TCP were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The implants were placed at the distal femur of 8 New Zeland rabbits, remaining for 2 weeks in vivo. After sacrifice, the implants were nondecalcified processed to 30 micro m thickness slides for histomorphology and bone-to-implant contact (BIC) determination. Statistical analysis was performed by one-way ANOVA at 95% level of significance considering implant surface as the independent variable and BIC as the dependent variable. Results: SEM and AFM showed that all surfaces presented rough textures and that calciu-hosohate particles were observed at the TCP group surface. Histologic evaluation showed intimate interaction between newly formed woven bone and all implant surfaces, demonstrating that all surfaces were biocompatible and osseoconductive. Significant differences in BIC were observed between the AB/AE and the AB/AE + TCP, and intermediate values observed for the TCP and TCP + Acid surfaces. Conclusion: irrespective of RBM processing variation, all surfaces were osseoconductive and biocaompatible. The differences in BIC between groups warrant further bone-implant interface biomechanical characterization

Buccal cells DNA extraction to obtain high quality human genomic DNA suitable for polymorphism genotyping by PCR-RFLP and Real-Time PCR

OBJECTIVE: The aim of this study was to evaluate, by PCR-RFLP and real-time PCR, the yield and quality of genomic DNA collected from buccal cells by mouthwash after different storage times at room temperature. MATERIAL AND METHODS: A group of volunteers was recruited to collect buccal cells using a mouthwash solution. The collected solution was divided into 3 tubes, one tube were used for immediate extraction and the remaining received ethanol and were kept at room temperature for 4 and 8 days followed by dna extraction. The concentration, purity and integrity of the dna were determined using spectrophotometry and electrophoresis. DNA quality differences among the three incubation times were also evaluated for genotyping EGF +61 a/g (rs 4444903) polymorphism by PCR-RFLP and for IRF6 polymorphism (rs 17015215) using real-time PCR. RESULTS: There was no significant difference of dna yield (p=0.75) and purity (p=0.86) among the three different incubation times. DNA obtained from different incubation times presented high-molecular weight. The PCR-RFLP and real time pcr reactions were successfully performed for all DNA samples, even those extracted after 8 days of incubation. All samples genotyped by real-time pcr presented c allele for irf6 gene polymorphism (homozygous: cc; heterozygous: Ct) and the C allele was used as a reference for Ct values. The samples presented the same genotype for the different times in both techniques. CONCLUSION: We demonstrated that the method described herein is simple and low cost, and that DNA can be extracted and pcr amplified after storage in mouthwash solution at room temperature

Design, Fabrication, and Application of Mini-Scaffolds for Cell Component in Tissue Engineering

publishersversionPeer reviewe

Alveolar bone repair with strontium- containing nanostructured carbonated hydroxyapatite

Objective: This study aimed to evaluate bone repair in rat dental sockets after implanting nanostructured carbonated hydroxyapatite/sodium alginate (CHA) and nanostructured carbonated hydroxyapatite/sodium alginate containing 5% strontium microspheres (SrCHA) as bone substitute materials. Methods: Twenty male Wistar rats were randomly divided into two experimental groups: CHA and SrCHA (n=5/period/group). After one and 6 weeks of extraction of the right maxillary central incisor and biomaterial implantation, 5 μm bone blocks were obtained for histomorphometric evaluation. The parameters evaluated were remaining biomaterial, loose connective tissue and newly formed bone in a standard area. Statistical analysis was performed by Mann-Withney and and Wilcoxon tests at 95% level of significance. Results: The histomorphometric results showed that the microspheres showed similar fragmentation and bio-absorbation (p>;0.05). We observed the formation of new bones in both groups during the same experimental periods; however, the new bone formation differed significantly between the weeks 1 and 6 (p=0.0039) in both groups. Conclusion: The CHA and SrCHA biomaterials were biocompatible, osteoconductive and bioabsorbable, indicating their great potential for clinical use as bone substitutes

Sexual dimorphism involved in the mesiodistal and buccolingual dimensions of permanent teeth

Studies indicate that tooth crown diameters are clinical markers for sex differentiation. Therefore, the aim of this study was to assess the degree of sexual dimorphism in different teeth. Maximum mesiodistal (MD) and buccolingual (BL) dimensions of 2400 permanent teeth from 100 pretreatment orthodontic dental study casts and clinical records (50 males and 50 females) from the Department of Pediatric Dentistry and Orthodontics, Federal University of Rio de Janeiro, Brazil, were examined. Comparison of the MD and BL dimensions between males and females was performed using the Student’s t test with alpha 0.05, effect size, and discriminant function analysis. Comparisons in MD and BL widths between sexes demonstrated that the combined mean in the female group presented reduction when compared with the male group, except for the BL dimension of tooth 26. In regard to the MD dimensions, statistically significant differences were observed in various dental groups. The greatest sexual dimorphism was observed in the left mandibular canine (p<0.001) with effect size over 0.8 (0.94), which characterizes large effect. In BL dimension, numerous teeth demonstrated statistical differences between the sexes. Our findings reinforced the magnitude of sexual dimorphism in tooth size, and, in addition, highlighted the differences in specific dental groups

Estudo do efeito da serie homologa de surfatantes anionicos e cationicos e de compostos purinicos na atividade da proteina tirosina fosfatase de baixa massa molecular relativa do rim bovino

Orientador: Pedro Luis Onofrio VolpeTese (doutorado) - Universidade Estadual de Campinas, Instituto de QuimicaDoutorad

Purificação e caracterização da fosfatase acida de rim bovino

Orientador: Hiroshi AoyamaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: A fosfatase ácida de BPM do rim bovino foi purificada 1.640 vezes até a homogeneidade, com rendimento de 7%, através de um procedimento envolvendo fracionamento com sulfato de amônio, tratamento ácido e cromatografia de trocaiônica em SP-Sephadex com eluição por íon-afinidade. Os critérios de pureza utilizados foram a A.E., PAGE, SDS-PAGE, filtração em gel (Superdex HR 70) e análise da composição de aminoácidos. A enzima purificada (A.E. de 100 µmol min-1 mg-1) é composta por uma cadeia polipeptídica simples e possui Mr de 13,6 e 17,8 kDa, como determinado através da filtração em gel e SDS-PAGE, respectivamente. A composição parcial de aminoácidos (Cys e Trp não foram determinados) foi obtida após a hidrólise ácida da proteína purificada seguida da análise dos resíduos de aminoácidos e evidenciou a existência de, pelo menos, 152 resíduos de aminoácidos. O estudo do efeito do pH na atividade enzimática revelou uma faixa de pH ótimo de 4,5 a 5,5. A enzima apresentou uma atividade máxima a 60°C e, nesta temperatura, maior estabilidade no pH 5,5. A atividade da enzima foi relativamente pouco sensível a diversos compostos, reagentes redutores de tióis e íons metálicos, exceto pela inibição por Zn2+ e Cu2+ e pela ativação por guanosina. O estudo de inibidores demonstrou insensibilidade ao tartarato e fluoreto e inibição por vanadato (Ki, 0,465 µM), piridoxal-5-fosfato (Ki, 2,18 µM), fosfato inorgânico (Ki, 0,769 mM), pCMB e molibdato de amônio. A energia de ativação para a hidrólise do p-NPP, determinada pelo gráfico de Arrhenius, foi de 43,31 kJ.mol-1. A análise da capacidade da enzima catalisar a reação de transfosforilação demonstrou que diversos álcoois atuaram como aceptores de fosfato neste tipo de reação, tendo se destacado o glicerol e o metanol como os melhores aceptores. Dos substratos testados, o p-NPP, ß-Naftil-P, a FMN e a Tyr-P foram os únicos hidrolisados significativamente com KM de 0,14; 0,4; 0,3 e 7,9 mM, respectivamente. A faixa de pH ótimo para a hidrólise da Tyr-P e FMN foi de 5,0 a 5,5Abstract: A low molecular weight bovine kidney acid phosphatase was purified 1640 fold to homogeneity, with 7% recovery, by a procedure involving ammonium sulfate fractionation, acid treatment, and SP-Sephadex ion-exchange chromatography with ion-affinity elution. The following homogeneity criteria were used: specific activity, PAGE, SDS-PAGE, gel filtration (Superdex HR 70) and amino acid composition. The purified enzyme (specific activity 100 µmol mL-1mg-1) contained a singIe peptide chain and had a reIative moIecuIar mass of 13.6 and 17.8 kDa as determined by gel filtration chromatography and SDS-PAGE, respectively. The partiaI amino acid composition of this enzyme, after acid hydroIysis, showed at least 152 amino acid residues. The amino acid Cys and Trp were not determined. The p-NPP hydrolysis reaction catalyzed by this enzyme had a broad pH optimum of 4.5-5.5 and maximal activity at 60°C. In this temperature the enzyme was more stable at pH 5.5. Reducing thiol compounds, metal ions and other different compounds did not affect significantly the enzyme activity except for the inhibition by Zn2+ and Cu2+ and activation by guanosine. The enzyme was also inhibited by vanadate (Ki, 0.465 µM), pyridoxal-5-phosphate (Ki, 2.18 µM), inorganic phosphate (Ki, .769 mM), pCMB and ammonium molybdate. Both tartrate and fluoride were very weak inhibitors. An activation energy value of 43.31 kJ.mol-1 was determined from Arrhenius plot for the hydrolysis of p-NPP reaction catalyzed by the enzyme. Both glycerol and methanol increased significantly the acid phosphatase activity, acting as good acceptors in the transphosphoryIation reaction also catalyzed by the enzyme. The apparent KM values obtained, at 37°C and pH 5.0, for the best substrates were 0.14 mM, 0.4 mM, 0.3 mM and 7.9 mM for p-NPP, ß-Naphtyl-P, FMN and Tyr-P, respectively. At the same conditions, a pH optimum value of 5.0-5.5, was obtained for the FMN- and Tyr-P-directed acid phosphatase reactionMestradoMestre em Ciências Biológica

Bone crestal height and bone density after third-molar extraction and grafting: a long-term follow-up study

The objective of this study was to evaluate the long-term influence of xenogenic grafts on bone crestal height and radiographic density following extraction of teeth. The right and left third lower molars of 22 patients were surgically extracted, and one randomly chosen socket was filled with a xenogenic graft (Gent-Tech). The contralateral molar was left to heal naturally, serving as a paired control. Digital intraoral radiographies were taken at surgery and 2, 6, and 24 months after, to evaluate bone density (BD) and alveolar bone crest to cementoenamel junction distance. The data obtained were subjected to two-way analysis of variance and Tukey`s test (alpha = 0.05). The significant decrease in cementoenamel junction distance observed for both groups was limited to the first 6 months. BD values increased significantly in the first 6 months, with no alterations observed up to 24 months for both groups. BD was higher for the experimental group at all time points (p < 0.05). Socket grafting with the xenogenic materials tested did not changed bone crestal height and bone radiographic density in the long term.CAPES Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Healing of critical-size cranial defects in guinea pigs using a bovine bone-derived resorbable membrane

Purpose: To investigate the healing of critical-size cranial bone defects (9-mm-diameter) in guinea pigs treated with a bovine bone-derived resorbable membrane. Materials and Methods: A sample of 42 guinea pigs was divided into test (n = 20), control (n = 20), and standard (n = 2) groups. A full-thickness trephine defect was made in the fronto-parietal bone of each animal. In the test group, the internal and external openings of the defect were each closed with a separate membrane, and the space between them was filled with blood clot and a central spacer. In the control group, the defect was filled only with the blood clot and spacer. At 1, 3, 6, and 9 months later, the calvarias (5 per period) for both the test and control groups were collected, fixed, radiographed, and histologically processed. The Standard-group animals were sacrificed immediately after surgery and used to determine the initial size of defect radiographically. The areas of defects in the radiographs were measured with image-analysis software and were compared between groups and periods by multiple regression analysis with the Bonferroni correction. Results: At 1 and 3 months, newly formed woven bone was histologically observed in both test and control groups. Radiographically, this new bone occupied an average of 32% of the defect area at 1 month and 60% at 3 months in the test group. In the control group, 21% of the defect was filled at 1 month and 39% at 3 months. However, the differences between treatments were not statistically significant (P > .05). At 6 and 9 months, a significant increase in newly formed lamellar bone was seen histologically in both groups. Radiographically, for the test group, the new bone occupied an average of 82% of the defect area at 6 months and 96% at 9 months. For the control group, new bone composed an average of 45% of the defect area at 6 months and 40% at 9 months. The differences between the test and control groups were statistically significant at 6 and 9 months (P < .05). Complete or almost complete filling of the defect was observed in several cases. Conclusion: It was concluded that the bovine bone-derived membrane is highly biocompatible and is able to promote good healing of critical-size defects in calvaria of guinea pig