Histomorphometric assessment of the influence of low-level laser therapy on peri-implant tissue healing in the rabbit mandible.
OBJECTIVE
The purpose of this study was to demonstrate the effect of low-level laser therapy (LLLT) on the peri-implant bone healing process in the rabbit mandible.


BACKGROUND
LLLT has been shown to accelerate tissue repair and osseointegration of implants placed into the rabbit tibia. However, the beneficial effects of LLLT have never been tested in the rabbit mandible, which would more closely mimic the human situation.


METHODS
Twenty-four male New Zealand rabbits were randomly divided into four groups of six animals each. All animals had their left mandibular incisors extracted, followed by immediate insertion of a titanium dental implant in the fresh socket. Three groups received LLLT [aluminum-gallium-arsenide (AlGaAs), λ=830nm, 50 mW, continuous wave (CW)] at three different energy densities per treatment session (E-5, 5 J/cm(2); E-10, 10 J/cm(2); and E-20, 20 J/cm(2)). Irradiation was performed every 48 h for 13 days, totaling seven sessions. One group received sham treatment (controls). Histological sections were obtained from each of the 24 mandibles dissected, without first decalcifying the specimens, and were stained with hematoxylin and eosin and Picrosirius red for histomorphometric evaluation. Bone-to-implant contact (BIC), bone formation area, and collagen fiber area were assessed by light microscopy.


RESULTS
Significant differences were found between group E-20 and all other groups (p<0.05). Histomorphometric evaluation showed significantly higher BIC and significantly more collagen fibers in group E-20.


CONCLUSIONS
Photobiostimulation with LLLT at an energy density of 20 J/cm(2) per session had a significant positive effect on new bone formation around dental implants inserted in the rabbit mandible.
1 Department of Oral and Maxillofacial Surgery, Hospital de Clínicas de Porto Alegre, School of Dentistry, Universidade Federal do Rio Grande do Sul , Porto Alegre, RS, Brazil .
Fabrício Poletto
FP
Massotti
Fernando Vacilotto
FV
Gomes
Luciano
L
Mayer
Marília Gerhardt
MG
de Oliveira
Carlos Eduardo
CE
Baraldi
Deise
D
Ponzoni
Edela
E
Puricelli
D000818:Animals; D028022:Low-Level Light Therapy; D008297:Male; D008334:Mandible / Q000473:pathology* / Q000528:radiation effects; D010012:Osteogenesis / Q000528:radiation effects; D011817:Rabbits; D014945:Wound Healing / Q000528:radiation effects*