Editorial Type:
Article Category: Other
 | 
Online Publication Date: 01 Feb 2015

Use of Resorbable Screws for Autogenous Onlay Block Graft Fixation: A Histological Analysis in Rabbits

DDS, MSc, PhD,
DDS, MSc, PhD,
DDS, MSc,
DDS, MSc, PhD,
DDS, MSc, PhD, and
DDS, MSc, PhD
Page Range: 23 – 29
DOI: 10.1563/AAID-JOI-D-12-00144
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The aim of the present in vivo study is to histologically evaluate and compare the use of resorbable screws based on poly(L-co-D,L lactide) 70:30 for fixation of autogenous bone grafts in rabbit tibiae. As control group, titanium (Ti-6Al-4V Grade V) screws were used. For this purpose, 15 white New Zealand male rabbits, aged 6 months and weighing between 3.8 and 4.5 kg, were used. From each animal, 2 total-thickness bone grafts were removed from the cranial vault: one was stabilized with a resorbable screw while the other was stabilized with a metallic one. Animals were divided into 3 groups, according to the sacrifice period: 3, 8, and 16 weeks postoperatively. After histological processing, cuts were stained with hematoxylin and eosin and submitted for descriptive histological analysis under light microscopy. It was found that the fixation system based on the polymer showed a histological behavior similar to metallic screws. For both groups, the bone graft was incorporated, with the presence of bone formation between the graft and receptor site. In none of the groups were undesirable inflammatory responses or foreign body reactions observed. Based on histological findings and on this experimental model, it is possible to conclude that the internal fixation system based on the poly(L-co-D,L lactide) 70:30 polymer is effective for fixation of autogenous bone grafts, with results that are comparable to the titanium fixation system.

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Figures 1 and 2 .

Figure 1. (a) Access to the rabbit's tibia plateau (recipient site). (b) Access to the rabbit's calvaria (donor site) from where bone grafts were harvested. (c) Cylindrical block grafts harvest from the calvaria using trephine burs. Figure 2. Titanium (a) and resorbable (b) screws used in the study. Both screws were 12-mm long and 2.0 mm in outer diameter.


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Figures 3–5 .

Figure 3. Hematoxylin and eosin–stained 3-week histological analysis of bone grafts fixed by titanium screws (×40 magnification). NB, new bone; G, graft; FCT, fibrous connective tissue; RS, recipient site; S, screw; IB, immature bone; BV, blood vessel; OC, osteocytes; RS, recipient site. Figure 4. Hematoxylin and eosin–stained 3-week histological analysis of bone grafts fixed by resorbable screws (×40 magnification). Figure 5. Hematoxylin and eosin–stained 8-week histological analysis of bone grafts fixed by titanium screws (×40 magnification).


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Figures 6–8 .

Figure 6. Hematoxylin and eosin–stained 8-week histological analysis of bone grafts fixed by resorbable screws (×40 magnification). Figure 7. Hematoxylin and eosin–stained 16-week histological analysis of bone grafts fixed by titanium screws (×40 magnification). Figure 8. Hematoxylin and eosin–stained 16-week histological analysis of bone grafts fixed by resorbable screws (×40 magnification).


Contributor Notes

Corresponding author, e-mail: antonini_fernando@hotmail.com
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