Bisphosphonates are frequently used for the antiresorptive treatment in bone metastasis diseases or for osteoporosis. A side effect of this therapy is osteonecrosis of the jaw. This inhibits osteoclast function, but osteoblasts and fibroblasts are also negatively affected in terms of impaired proliferation. Additive local treatment with platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) promotes adhesion, proliferation and migration of cells due to high concentrations of growth factors like PDGF, TGF and IGF. The aim of the study was to investigate the effect of PRP or PRF on proliferation, migration and viability of osteoblasts and oral fibroblasts, treated with zoledronic acid (ZA). ZA treated fibroblasts and osteoblasts were exposed to PRP/PRF. Cell proliferation, migration and viability were measured using the real-time cell-analyzer assay (RTCA), the scratch assay and the MTT assay. There was a significant increase in closure of the scratch area by PRP/PRF treated osteoblasts (PRP = 40.6%, PRF = 100.0%, NC = 0.0%) as well as fibroblasts (PRP = 100.0%, PRF = 100.0%, NC = 12.7%) in comparison to the group of negative control (all p ≤ 0 . 05 ). Furthermore, the negative effect of ZA on cell migration was generally reduced in both cell lines using PRP/PRF. The viability and proliferation of cells decreased after exposure to ZA, whereas we observed an enhancement of cell viability within 24 hours by application of PRP/PRF in ZA treated cells. The negative effect of ZA on cell proliferation was especially reduced when using PRF. The use of PRF/PRP improves the behavior of ZA-treated cells, but PRF appears to have an advantage in comparison to PRP. This study demonstrates that treatment with PRF/PRP may have positive effects in the therapy of Bisphosphonate-Related Osteonecrosis of the Jaw (BRONJ).

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Background Guidelines recommended for resection of oral cancer define a free margin of ≥5 mm as clear and safe (R0). This statement was questioned recently based on the assumption that different surgical margins may hold different risk categories. The aim of this study was to investigate the impact of stratification of the surgical margins on the survival outcome of patients with oral cancer. Methods In a cohort of 753 patients, the hazard ratio for local recurrence‐free survival (LRFS), overall survival (OS), and oral cancer‐specific survival (OCSS) were estimated for R0 resection, the close margin of 1–4 mm, involved resection borders but with free frozen sections. Competing risk factors were considered in the statistical regression model. Results One hundred seventy‐three (23%) patients developed local recurrence and 316 (42%) died in the 5 follow‐up years. There was a gradual improvement in the LRFS, OCSS, OS with the increase of clear margin. OS showed a similar tendency. Conclusion Not all patients with an R0cm status carry the same risk for impaired LRFS, OCSS, and OS. Their risk to develop recurrence is higher than those patients with R0 ≥5 mm but stratified risk management can be recommended according to the presented results.

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Background/Aim: We compared postoperative radiotherapy (PORT) to surgery only (SO), and supraomohyoidal neck dissection (SOHND) to modified radical neck dissection (MRND) in patients with pT1-T2 squamous cell carcinomas of the oral cavity (OSCC) and a single cervical lymph node metastasis (pN1) in terms of overall survival (OS), oral cancer specific survival (OCSS), and regional recurrencefree survival (RRFS), in a prospective cohort study. Patients and Methods: We included patients with pT1-T2 pN1 OSCC with no distant metastasis and estimated the survival probabilities using the Kaplan-Meier method and calculated hazards ratios (HR) for PORT vs. SO and MRND vs. SOHND using adjusted Cox regression models. Results: A total of 51 patients (26 SO vs. 25 PORT, 9 SOHND vs. 42 MRND) were evaluated. Patients who received PORT were more likely to be younger and healthier. OS at 5 years was 41% and 87% in the SO and PORT groups, respectively. OS at 5 years was 52% and 67% in the in the SOHND and MRND groups, respectively. Both OCSS and RRFS were improved by PORT.Extending neck dissection was not associated with improved OS (HR = 0.83). Conclusion: PORT is associated with preferable OS, OCSS, and RRFS in pT1-2 pN1 oral cancer and should be recommended regularly.

Background Osteoblast adhesion is a crucial step in osseointegration of dental implants and can be influenced by modification of implant surface or the addition of bioactive agents. Bisphosphonates affect bone turnover, attenuating bone healing in implants patients. PRP and PRF are sources of growth factors involved in osteoblast adhesion, improving subsequent bone healing. The aim of the study was to investigate the impacts of PRP and PRF on adhesion of bisphosphonate‐pretreated osteoblasts on titanium implant surfaces using the cell‐count wash assay, the MTT‐assay as well as real‐time‐cell analyser assay and scanning electronic microscopy. Methods Titanium implants were colonised for 24 hours with osteoblasts and zolendronic acid, PRP or PRF in different combinations. Afterwards, primary osteoblast adhesion was evaluated by counting the number of attached cells using a wash‐assay cell analysis. Scanning electronic microscopy was performed and evaluated semi‐quantitatively to assess the influence of the different groups on the ultrastructural cell morphology, such as cell size and shape as well as length and number of filopodia. Results Zoledronic acid led to a decrease of osteoblast adherence onto implant surface. This effect was reversed by adding PRP or PRF. Scanning electronic microscopy showed that both PRP and PRF increased number and length of filopodia in adherent osteoblasts. Conclusions Zoledronic acid decreased osteoblast adhesion on implant surfaces, and PRF as well as PRP increased primary adhesion of zoledronic acid‐treated osteoblasts on implant surfaces in vitro. Therefore, PRP and PRF may improve initial bone apposition and primary healing of dental implants in patients with bisphosphonate treatment.

Indirect co-culture models with osteoclasts including oral cell lines may be influenced by M-CSF and RANKL in the common cell medium. Therefore, we investigated the viability and proliferation of osteoblasts (OB), fibroblasts (FB) and oral keratinocytes (OK) under stratified medium modification and assessed the differentiation of osteoclasts in each co-culture. The impact of M-CSF and RANKL in the common OC co-culture was assessed for OB, FB and OK via MTT assay via DAPI control. The multinuclearity and function of OC were evaluated by light microscopy, DAPI staining, resorption assay and FACS analysis. The PBMC showed the highest differentiation into OC after an incubation period of 7 days. Furthermore, co-culture with OB enhanced the number of differentiated multinucleated OC in comparison with monoculture, whereas co-culture with OK decreased PBMC multinuclearity and OC differentiation. FB did not influence the number of differentiated OC in a co-culture. RANKL and M-CSF reduction had no impact on OC differentiation in co-culture with FB or OB, whereas this medium modification for OK attenuated PBMC multinuclearity and OC differentiation in all approaches. Supplementation of RANKL and M-CSF can be modified for a co-culture of PBMC with FB or OB without disturbing OC differentiation. Thus, pathogenic processes of bone remodelling involving OB, OC, FB and OK in the oral cavity can be investigated thoroughly.