Dimensional Ridge Preservation with a Novel Highly Porous TiO(2) Scaffold: An Experimental Study in Minipigs

Abstract

Despite being considered noncritical size defects, extraction sockets often require the use of bone grafts or bone graft substitutes in order to facilitate a stable implant site with an aesthetically pleasing mucosal architecture and prosthetic reconstruction. In the present study, the effect of novel TiO(2) scaffolds on dimensional ridge preservation was evaluated following their placement into surgically modified extraction sockets in the premolar region of minipig mandibles. After six weeks of healing, the scaffolds were wellintegrated in the alveolar bone, and the convex shape of the alveolar crest was preserved. The scaffolds were found to partially preserve the dimensions of the native buccal and lingual bone walls adjacent to the defect site. A tendency towards more pronounced vertical ridge resorption, particularly in the buccal bone wall of the nongrafted alveoli, indicates that the TiO(2) scaffold may be used for suppressing the loss of bone that normally follows tooth extraction.

Figures

Figure 1

Clinical photographs illustrating the sham and scaffold sites (A) and the socket sites covered by mucosa flaps that were retained in position with interrupted sutures (B).

Figure 2

Representative three-dimensional illustration of the scaffold (right) and sham (left) sites with their corresponding mesial roots after six weeks of healing (reconstructed from micro-CT data using CTvox).

Figure 3

Schematic drawing representing the locations of the morphometric measurements performed in this study with the grey rectangle showing the approximate shape and place of the scaffolds/shams. (a) Vertical parameters: buccal bone height (BHH) and lingual bone height (LBH). For scaffold and sham sites, a straight line was drawn along the edges of the scaffold/sham, and bone height was measured where this line intersected the bone crest. In addition, the vertical height difference between buccal and lingual bone crest was measured (lines b and l in (b)). (b) Horizontal parameters: buccal and lingual alveolar wall width (A, B, C) and buccal and lingual total bone width (A′, B′, C′) 1, 3, and 5 mm apical of the buccal and lingual bone crest, all measured perpendicular to the long axis of the defect. (c) Vertical bone loss: difference in height (H) between original bone level and bone level at defect site after six weeks of healing.

Figure 4

The scaffolds were well integrated in the alveolar bone, and the TiO2 scaffold was not found to interfere with the normal healing sequence of the extraction socket (a–d). In few isolated instances (2/11), small portion of the scaffold was exposed above the newly formed bone (e), while the loss of ridge height at a sham site is shown in (f).

Figure 5

(a) Box plot showing the medians and distributions of the difference in buccal and lingual bone height (BBH and LBH) and height difference of buccal and lingual bone crest (b-l) in comparison to equivalent measurement on the corresponding mesial root of each defect site (Δh = defect − root). (b) Box plot of vertical bone loss relative to the original bone level measured from central micro-CT sections cut in the mesial-distal direction. The whiskers of the plots represent the 5th and 95th percentiles, n = 11.

Figure 6

Box plot showing the medians and distributions of difference in buccal and lingual alveolar wall (A–C) and total bone thickness (A′, C′) in comparison to equivalent measurement on the corresponding mesial root of each defect site 1 mm (A), 3 mm (B), and 5 mm (C) apical of the buccal and lingual bone crest (Δw = defect − root). The whiskers of the plot represent the 5th and 95th percentiles, *statistically significant difference in this parameter (P < 0.05), n = 11.