Periodontal regenerative effect of a bovine hydroxyapatite/collagen block in one-wall intrabony defects in dogs: a histometric analysis

Abstract

Purpose: The aim of this study was to elucidate the effect of a bovine hydroxyapatite/collagen (BHC) block in one-wall intrabony periodontal defects in dogs.

Methods: A one-wall intrabony periodontal defect (4 mm wide and 5 mm deep) was prepared bilaterally at the mesial side of the mandibular fourth premolar in five beagle dogs. After thorough root planing, block-type BHC (4×5×5 mm) was placed on one side. The contralateral defect area did not receive any material as a sham-surgery control. Histological analysis of the sites was performed after an 8-week healing period.

Results: Two of five samples in the experimental group healed well without dissipation of the graft materials, and histological analysis revealed excellent regeneration of the periodontal tissues. However, most of the grafted materials had been displaced in the other three samples, leaving only a small portion of the graft. The measured parameters exhibited large standard deviations, and the mean values did not differ significantly between the experimental and sham-surgery control sides.

Conclusions: The application of BHC alone-without a barrier membrane-to wide, one-wall intrabony periodontal defects yielded inconsistent results regarding both periodontal regeneration and substantivity of the graft materials. Thus, the use of a barrier membrane for noncontained-type defects is recommended to improve the stability of the grafted material, and to condense it.

Keywords: Collagen; Guided tissue regeneration; Histology.

Figure 1

Clinical photograph showing the bovine hydroxyapatite/collagen block graft site (A) and the sham-surgery control site (B) in one-wall, intrabony, periodontal defects prepared at the mesial side of the mandibular fourth premolar.

Figure 2

Histological view of a well-healed sample (#1) in the experimental group (H&E staining). (A) Low magnification. White arrowhead apical end of the junctional epithelium; black arrowhead, coronal end of the new cementum; yellow arrowhead, coronal end of the new bone; star residual graft material (scale bar=1 mm). (B) Higher magnification at the junctional epithelium (scale bar=100 µm). (C) Higher magnification at the middle area of the root surface (scale bar=50 µm). (D) Magnified view at the notch (scale bar=100 µm). (E) Higher magnification of the residual graft material (scale bar=250 µm).

Figure 3

Histological view of a well-healed sample (#2) in the experimental group (H&E staining). (A) Low magnification. Arrowheads as in Fig. 2 (scale bar=1 mm). (B) Higher magnification at the root surface covered by new cementum and lined with cementoblast-like cells (arrowheads; scale bar=100 µm). (C) Lacunae of root resorption by odontoclasts (black arrowheads) and subsequent apposition of new cementum (white arrowhead; scale bar=50 µm).

Figure 4

Histological view of a poorly healed sample in the experimental group (H&E staining). (A) Low magnification. Arrowheads as in Fig. 2 (scale bar=1 mm). (B) Higher magnification at the notch area; minimal new bone was formed (scale bar=100 mm). (C) Fibrous encapsulated graft material (arrowheads; scale bar=250 µm). (D) Degradation of the residual graft material. Arrowheads, osteoclast-like cells (scale bar=50 µm).

Figure 5

Graph illustrating the mean percentage values of the measured parameters.

Figure 6

Comparison of the mean percentage values of the measured parameters within the experimental group according to healing pattern (favorable or unfavorable).