Journal of Dental Medicine

Statement of Problem: Several methods are used to enhance bone repair and new bone formation, and bone matrix gelatin (BMG) is recently introduced.

Purpose: The purpose of this histologic and histomorphometric study was to assess the osteogenic potential and the quantity of new trabecular bone formation after implantation of OCP and BMG alone and in combination into the cranial defects in rat.

Materials and Methods: In this experimental study, 100 young male Sprague Dawley rats (5-6 weeks age and 120-150gr weight) were divided into four groups randomly. A full thickness standard trephine defect 5mm in diameter was made in the rat’s parietal bone, and 5mg of OCP, BMG alone and in combination were implanted into the defects. No OCP and BMG particles were implanted in control group which was otherwise treated identically. On the 5th, 7th, 14th, 21st and 56th days after implantation, the rats were killed and bone samples collected. After processing the samples by routine histological procedures, 5µm thick sections of bone were cut and stained with Haematoxyline & Eosin (H&E) and Alcian Blue and studied histologically and histomorphometrically using light microscope and eyepiece graticule. The amount of newly formed bone was quantitatively measured by the use of histomorphometric methods. Data were analyzed with SAS statistical package using ANOVA and Duncan tests.

Results: In the experimental groups, the new bone formation was initiated from the margin of defects during 5-14 days after implantation. During 14-21 days after implantation, bone marrow cavities and bone marrow tissues in newly formed bone were seen. By the end of the study, the newly formed bone increased and was relatively matured and almost all of the implanted materials were absorbed. In control group, at the end of the study, a few clusters of new bone were seen near to the defect margins and host bone. The histomorphometric analysis indicated statistical significant differences in the amount of newly formed bone between the experimental and control groups (P<0.05).

Conclusion: Implants of OCP/BMG appear to stimulate bone induction and new bone growth in bone defects greater than the other groups and these biomaterials could be used in the repair of cranial bone defects in clinical situations.

  Background and Aims: The purpose of this study was to evaluate the tissue responses to octacalcium phosphate (OCP) and calcium hydroxide (CH) used as direct pulp capping (DPC) materials in cat teeth.

  Materials and Methods: 72 premolar teeth of 9 cats were selected and divided into 3 groups (Two experimental and one control group). After the cats had been anesthetized, the pulp were exposed and capped directly with OCP, CH or no capping material as control group. The cavities of all three groups were filled with Glass ionomer cement (GI). Histological evaluations were performed at two, four and eight weeks after pulp capping. After tissue preparation procedures, paraffin blocks were prepared. After preparation and staining of the sections, the relevant variables were measured by optical microscope. The results were analyzed using Mann-Whitney U and Chi-square tests ( α =0.05).

  Results: Two weeks after pulp capping, all specimens in three groups showed mild to sever inflammation. The formation of hard tissue (dentinal bridge) at in the exposed areas of the experimental groups was more noticeable for calcium hydroxide than that of octacalcium phosphate group. These differences were statistically significant (P<0.001). At four weeks, hard tissues were observed in both groups which were more evident for the CH group and there were statistically significant difference between two experimental groups (p<0.003). At eight weeks, continuous hard tissues were observed in both groups and there were no statistically significant difference between them (P>0.05), but hard tissues continuity were better for in the OCP than that of the CH.

  Conclusion: It seems that the formation of hard tissue in CH because of its porosities had a worse percentage in sealing of the pulp than the OCP .