Single-drill implant induces bone corticalization during submerged healing: an in vivo pilot study

Abstract

Purpose: The aim of the present paper is to evaluate a simplified implant site preparation technique to preserve bone bulk and enhance osseointegration using a new conical self-tapping implant in cancellous bone.

Materials and methods: Ten Expander® 3.8 × 10 mm implants (NoDrill®, Milano, Italy) were inserted in the right side (test group) of sheep's iliac crest using only the pilot drill 1.8 mm in diameter. Ten 3.8 × 10 mm Dynamix® implants (Cortex, Shlomi, Israel) were inserted in the right side (control group) of the same animals following the drilling protocol provided by the manufacturer. Histological, histomorphometric, and biomechanical analyses were performed after 2 months.

Results: Implants that belonged to the test group showed a %BIC of 70.91 ± 7.95 while the control group implants had a %BIC value of 49.33 ± 10.73. The %BV was 41.83 ± 6.30 in the test group and 29.61 ± 5.05 in the control group. These differences were statistically significant. A phenomenon of osseocorticalization, characterized by more bone volume percentage around implant area than in the neighboring areas, caused by implant threads geometry, was evident in the test group.

Conclusion: This surgical protocol allows to insert an innovative fixture geometry in low-density bone using only a pilot drill. This technique demonstrated many clinical and histological advantages with respect to standard implant drilling procedures and classical implant geometry.

Keywords: Bone histology; Dental implant; Low-density bone; Osseocorticalization; Osseointegration.

Figure 1

Test group. The implant achieved a high osseointegration degree. The newly formed bone appeared well interconnected with the pre-existing trabeculae. The “corticalization” phenomenon is evident: the bone appears densified around a titanium implant (magnification × 8—toluidine blue)

Figure 2

Test group. Implants in the test group showed an extremely high percentage of bone directly contacted to implant surface (magnification × 25—toluidine blue)

Figure 3

Test group. The present histological photo showed a continuous thin layer of newly formed bone along the neck area of the implant (magnification × 25—toluidine blue)

Figure 4

Control group. No bone condensation was possible with traditional burs and standard implant (magnification × 25—toluidine blue)

Figure 5

Control group. Implants belonging to the control group showed some small surface areas not contacted with bone (magnification × 25—toluidine blue)

Figure 6

Control group. Some implant thread areas were not covered by bone layer (magnification × 25—toluidine blue)