Fernanda Gomes de Moraes

Microscopic and radiographic analysis of the effect of particle size of demineralized bovine cancellous bone matrix on the repair of bone defects in femurs of rabbits

The bone tissue has a great regenerative potential, with ability to completely restore its structure and original functions. In some situations, though, bone defects cannot be self-repaired, thus requiring the use of grafts for a correct treatment and good prognosis. This work aimed at microscopically analyzing the effect of the particle size of demineralized bovine cancellous bone matrix in micro and macrogranular forms on the repair of bone defects in femurs of rabbits, with blood clot used as control. At 1, 3 and 6 months after implantation of the materials, the animals were killed and the anatomic specimens were removed. A foreign body-type granulomatous reaction containing macrophages and multinucleated giant cells in contact with the implanted particles was observed. These results suggest a failure in demineralization and/or interruption of the antigenic potential during production of the biomaterial. It is concluded that the size of the particles did not influence the evolution of the repair process of bone defects, acting only as bone-filler substances, and that the material implanted should be improved by quality control during production, since it may represent a good alternative for bone graft.

Microscopic analysis of dog dental pulp after pulpotomy and pulp protection with mineral trioxide aggregate and white Portland cement

Considering previous studies on the similarity between the chemical composition of the mineral trioxide aggregate and the Portland cement, the purpose of this study was to investigate the pulp response of dogs teeth after pulpotomy and direct pulp protection with MTA Angelus and white Portland cement. Thirty eight pulp remnants were protected with these materials. One hundred and twenty days after treatment, the animals were sacrificed and the specimens removed and prepared for histological analysis. Both materials demonstrated the same results when used as pulp capping materials, inducing hard tissue bridge formation and maintaining pulp vitality in all specimens. The MTA Angelus and the white Portland cement showed to be effective as pulp protection materials following pulpotomy.

Influence of calcium hydroxide on dyes for dentin labeling, anlyzed by means of a new methodology

The objective of this study was to evaluate the influence of calcium hydroxide in intracanal dressing on the ability of the dyes rhodamine B and methylene blue to label the dentine. Forty extracted human mandibular premolars had their canals instrumented and were divided into four groups: in two groups, the canals were filled with a calcium hydroxide paste and the others remained in distilled water. After 15 days, in two groups (with and without dressing), the canals were obturated with sealer containing methylene blue, whereas the others contained rhodamine B. For analysis, the roots were transversally sectioned in their cervical, medium and apical thirds, and the labeling was analyzed. The Mann-Whitney test showed statistically significant difference between the dressing/methylene blue group and the others. Based on these results, it was concluded that calcium hydroxide in intracanal dressing negatively interferes with the labeling ability of methylene blue.

Influence of the EDTA, Nd:YAG laser and association of both on the filling of artificial lateral root canals.

This study aimed at evaluating the influence of EDTA, Nd:YAG laser and the combination of both for filling of artificial lateral root canals. Forty-five human mandibular premolars were employed, on which three artificial lateral root canals were prepared by means of a reamer with a similar diameter to a K file #15. The teeth were instrumented through the stepback technique employing Gates Glidden burs at the middle and cervical thirds and manual files at the apical portion, and irrigation with 1% sodium hypochloride. The teeth were divided in three groups: Group 1 -EDTA for 5 minutes; Group 2 -application of Nd:YAG laser at 15 Hz, 100 mJ and 1.5 Watts; and Group 3 - association of both. Roots were filled through the Taggers hybrid technique, radiographed and the radiographs were digitized. Scores were assigned to the filling of the lateral root canals. Statistical analysis revealed no significant differences between the entire groups and also on the analysis of each third.