Photobiomodulation with a 645 nm Diode Laser of Saos-2 Cells and Platelet-Rich Plasma: The Potential for a New Mechanism of Action.

Objective: The main focus of this in vitro study was to highlight possible differences between outcomes of photobiomodulation performed in the presence or absence of growth factors derived from platelet-rich plasma. Background: Photobiomodulation has garnered increasing attention, thanks to a large number of controlled clinical trials that have proven its efficacy in various oral pathologies. Nevertheless, the mechanism of action is still a matter of debate. Materials and methods: The cell model used was Saos-2ATTC HTB-85, a human osteosarcoma cell line that retains an osteogenic potential matching that of osteoblastic cells. Photobiomodulation was performed with a 645 nm diode laser; we investigated three different fluence values (2, 5, and 10 J/cm2) delivered with 3 different irradiation times (1, 2, and 4 min). The design of the study included a case-control structure. Cell viability was assessed by resazurin reduction assay before laser irradiation. We assessed cell differentiation by Alizarin-red Sigma Aldrich assay 48 h after the last laser irradiation. Results: Results show that the combination of photobiomodulation and platelet-rich plasma can lead to a statistically significant increase in both proliferation and differentiation rates. Conclusions: Only a defined amount of energy, that is, a fluence of 5 J/cm2 delivered in 2 min and of 10 J/cm2 in 4 min, was proven to be the most effective in the presence of platelet-rich plasma to induce cell proliferation and calcium deposition.

Medication-related osteonecrosis of the jaw: risk factors in patients under biphosphonate versus patients under antiresorptive-antiangiogenic drugs.

BACKGROUND: Biphosphonate-related osteonecrosis of the jaw (BRONJ) is a potential side effect associated with the administration of bisphosphonates; the aim of this work is to highlight the possible epidemiological differences between two groups of patients affected by medication related osteonecrosis of the jaw (MRONJ) treated at the Center of Oral Medicine, Pathology and Laser Surgery of the Academic Hospital at the University of Parma, Italy, between January 2004 and June 2016. METHODS: Medical charts of 303 patients (214 females and 89 males, mean age: 67 years old) treated at the Center of Oral Medicine, Pathology and Laser Surgery of the Academic Hospital at the University of Parma, between January 2004 and June 2016, were retrospectively analyzed. Patients were divided in 2 groups according to drugs therapy they underwent: group 1 (G1) including patients treated with bisphosphonates alone and group 2 (G2) including patients receiving antiresorptive-antiangiogenic drugs in association with bisphosphonates or antiresorptive-antiangiogenic drugs alone. Than 269 MRONJ sites treated with 5 different therapeutical approaches were analyzed. RESULTS: Results showed G1 consisting mainly in female patients undergoing bisphosphonates for oncologic disease, stage II was most frequently diagnosed and MRONJ developed mainly after dental extraction or bone surgery. G2 consisted mainly in males patients, whom took antiresorptive-antiangiogenic drugs in association with bisphosphonate or antiresorptive-antiangiogenic drugs alone for oncologic disease. Stage II was most frequently diagnosed and MRONJ developed most frequently "spontaneous". CONCLUSIONS: This study showed how a new population affected by MRONJ is emerging. Men affected by kidney cancer treated with new antiresorptive-antiangiogenic drugs will represent a growing portion of the pool of patients at risk. In our experience, a strict follow-up is of outmost importance to early detect MRONJ also in patients with spontaneous cases. When MRONJ occurs, surgical laser treatment with Er:YAG seems to represent the option with highest percentage of success; for patients with contraindication to surgery, LLLT helps to improve outcomes of the medical therapy.