Surface characterization and osteoblast-like cells culture on collagen modified PLDLA scaffolds

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Bladder augmentation in rabbits with anionic collagen membrane, with or without urotelial preservation. Cistometric and hystologic evaluation

The use of bowel segments to perform bladder augmentation is associated with several metabolic and surgical complications. A great variety of synthetic materials, biodegradable or not, have been tested. Collagen-based biomaterials have shown effectiveness for the regeneration and obtainment of a functional bladder. Assess the functional and histological response of the rabbit bladder to anionic collagen membrane (ACM), either when it is anastomosed to the bladder or it is placed onto bladder after vesicomyectomy. In 15 male rabbit a partial cystectomy was performed. After 4 weeks they were divided in 3 groups. Group 1 (G1) - bladder augmentation with ACM. Group 2 (G2) ACM is placed onto bladder after vesicomyectomy. Group 3 (G3) control group. Maximal bladder capacity (MBC) and weight were assessed with 4 (M1), 8 (M2) and 12 (M3) weeks after partial cystectomy. In M3 was performed the sacrifice and extraction of the bladder and kidneys for anatomopathologic study. There were neither bladder stones, nor implant extrusion in M3. There was a significant increase in MBC in G1 and G2 (p<0.05), but no statistical differences in G3 (p=0.35). There is no significant difference comparing G1 and G2. In M3, both groups have shown a bigger MBC than G3 (p<0.05). The microscopic assessment showed an inflammatory reaction in the bladder augmented, with urothelium preserved. The ACM was effective for the increase of MBC. The bladders with preservation of the urothelium have shown an extensive inflammatory process.

Effect of collagen matrix saturation on the surface free energy of dentin using different agents

The surface free energy of conditioned-dentin is one of the factors that interfere with monomeric infiltration of the interfibrillar spaces. Saturation of the tooth matrix with different substances may modulate this energy and, consequently, the wettability of the dentin. To evaluate the influence of different substances used to saturate conditioned-dentin on surface free energy (SFE) of this substrate. Dentin blocks (4 × 7 × 1 mm, n = 6/ group), obtained from the roots of bovine incisors, were etched using phosphoric acid for 15 seconds, rinsed and gently dried. The surfaces were treated for 60 seconds with: ultra-purified water (H20-control); ethanol (EtOH), acetone (ACT), chlorhexidine (CHX), ethylenediaminetetraacetic acid (EDTA); or sodium hypochlorite (NaOCl). The tooth surfaces were once again dried with absorbent paper and prepared for SFE evaluation using three standards: water, formamide and bromonaphthalene. Analysis of variance (ANOVA) and Dunnet's tests (a = 0.05) were applied to the data. Ethylenediaminetetraacetic acid was the only substance that caused a change to the contact angle for the standards water and formamide, while only EtOH influenced the angles formed between formamide and the dentin surface. None of the substances exerted a significant effect for bromonaphtha-lene. In comparison to the control, only EDTA and NaOCl altered both polar components of the SFE. Total SFE was increased by saturation of the collagen matrix by EDTA and reduced when NaOCl was used. Saturation of the collagen matrix by EDTA and EtOH changed the surface free energy of the dentin. In addition, the use of NaOCl negatively interfered with the properties evaluated. The increase of surface free energy and wettability of the dentin surface would allow higher penetration of the the adhesive system, which would be of importance to the clinical success of resin-dentin union.

Bone defect repair on the alveolar wall of the maxillary sinus using collagen membranes and temporal fascia: an experimental study in monkeys

Few studies has been done using guided bone regeneration in maxillary sinus defects. AIM: To assess the bone repair process in surgical defects on the alveolar wall of the monkey maxillary sinus, which communicates with the sinus cavity, by using collagen membranes: Gen-derm - Genius Baumer, Pro-tape - Proline and autologous temporal fascia. MATERIALS AND METHODS: In this prospective and experimental study, orosinusal communications were performed in four tufted capuchin monkeys (Cebus apella) and histologic analysis was carried out 180 days after. RESULTS: In the defects without a cover (control), bone proliferation predominated in two animals and fibrous connective tissue predominated in the other two. In defects repaired with a temporal fascia flap, fibrous connective tissue predominated in three animals and bone proliferation predominated in one. In the defects repaired with Gen-derm or Pro-tape collagen membranes there was complete bone proliferation in three animals and fibrous connective tissue in one. CONCLUSIONS: Surgical defect can be repaired with both bone tissue and fibrous connective tissue in all study groups; collagen membranes was more beneficial in the bone repair process than temporal fascia or absence of a barrier.