Dynamics of bone healing after osteotomy with piezosurgery or conventional drilling - histomorphometrical, immunohistochemical, and molecular analysis.
BACKGROUND
Piezosurgery is an osteotomy system used in medical and dental surgery. Many studies have proven clinical advantages of piezosurgery in terms of quality of cut, maneuverability, ease of use, and safety. However, few investigations have tested its superiority over the traditional osteotomy systems in terms of dynamics of bone healing. Therefore, the aim of this study was to evaluate the dynamics of bone healing after osteotomies with piezosurgery and to compare them with those associated to traditional bone drilling.


METHODS
One hundred and ten rats were divided into two groups with 55 animals each. The animals were anesthetized and the tibiae were surgically exposed to create defects 2 mm in diameter by using piezosurgery (Piezo group) and conventional drilling (Drill group). Animals were sacrificed at 3, 7, 14, 30 and 60 days post-surgery. Bone samples were collected and processed for histological, histomorphometrical, immunohistochemical, and molecular analysis. The histological analysis was performed at all time points (n = 8) whereas the histomorphometrical analysis was performed at 7, 14, 30 and 60 days post-surgery (n = 8). The immunolabeling was performed to detect Vascular Endothelial Growth Factor (VEGF), Caspase-3 (CAS-3), Osteoprotegerin (OPG), Receptor Activator of Nuclear Factor kappa-B Ligand (RANKL), and Osteocalcin (OC) at 3, 7, and 14 days (n = 3). For the molecular analysis, animals were sacrificed at 3, 7 and 14 days, total RNA was collected, and quantification of the expression of 21 genes related to BMP signaling, Wnt signaling, inflammation, osteogenenic and apoptotic pathways was performed by qRT-PCR (n = 5).


RESULTS
Histologically and histomorphometrically, bone healing was similar in both groups with the exception of a slightly higher amount of newly formed bone observed at 30 days after piezosurgery (p < 0.05). Immunohistochemical and qRT-PCR analyses didn't detect significant differences in expression of all the proteins and most of the genes tested.


CONCLUSIONS
Based on the results of our study we conclude that in a rat tibial bone defect model the bone healing dynamics after piezosurgery are comparable to those observed with conventional drilling.
Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine - Harvard University, 188 Longwood Avenue, Boston, MA 02115 - REB 403, USA. Giuseppe_Intini@hsdm.harvard.edu.
Jônatas Caldeira
JC
Esteves
Elcio
E
Marcantonio
Ana Paula
AP
de Souza Faloni
Fernanda Regina Godoy
FR
Rocha
Rosemary Adriana
RA
Marcantonio
Katarzyna
K
Wilk
Giuseppe
G
Intini
D000818:Animals; D001178:Arthroplasty; D015415:Biomarkers / Q000378:metabolism; D001861:Bone Regeneration / Q000235:genetics; D001842:Bone and Bones / Q000378:metabolism* / Q000473:pathology*; D005786:Gene Expression Regulation; D007150:Immunohistochemistry; D010027:Osteotomy; D059745:Piezosurgery; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014945:Wound Healing / Q000235:genetics
D015415:Biomarkers