Histomorphometric Assessment of the Influence of Low-Level Laser Therapy on Peri-Implant Tissue Healing in the Rabbit Mandible

Abstract

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 data: 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. Materials and 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-galliumarsenide (AlGaAs), k = 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.

Review of light parameters and photobiomodulation efficacy: dive into complexity

“…For instance, three papers looked at peri-implant bone regeneration after PBM. Menezes et al 98 found that 20 J∕cm 2 was the best dose to deliver, whereas Massotti et al 22 and Mayer et al 23 found that 20 J∕cm 2 was the worst dose to deliver.…”

“…[16][17][18] Doses for deeper-seated targets should be in the 10 to 50∕cm 2 range. [19][20][21] While many studies have shown a positive effect of PBM, 17,18,21 a number have failed to show a benefit 22,23 and, in fact, some reports have shown negative outcomes at what are reported to be the same parameters of irradiation as other positive studies. Unfortunately, in many of the historical studies, important laser parameters were omitted or incorrectly presented.…”

Photobiomodulation in Periodontology and Implant Dentistry: Part 2

“…Most of these studies reported positive effects in terms of promotion of bone formation around Ti implants, and higher bone implant contacts (BICs) were reported ( Table 1). [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Many researchers have confirmed that low-level light therapy can promote bone formation by stimulatory effects on osteoblasts, which can lead to greater osteo-integration of Ti implants. This has been evaluated in different study designs and laser irradiation parameters.…”

Promotion of Tissue Healing and Regeneration with Low-Reactive Level Laser Therapy Using Diode Lasers in Dental Field: Review of Basic and Clinical Research

“…Rabbit, dental implant placement 2015 Massotti et al 45) ・830 nm ・5, 10, 20 J/cm 2 ・every 48 h for 13 days after the extraction 1) Control 2) LLLT (5 J/cm 2 ) 3) LLLT (10 J/cm 2 ) 4) LLLT (20 J/cm 2 ) histological analysis Histomorphometric evaluation showed significantly higher bone-to-implant contact and significantly more collagen fibers in LLLT at 20 J/cm 2 group.…”