Hydrocolloids were the first elastic materials to be used in the dental field. Elastic impression materials include reversible (agar-agar), irreversible (alginate) hydrocolloids and synthetic elastomers (polysulfides, polyethers, silicones). They reproduce an imprint faithfully, providing details of a high definition despite the presence of undercuts. With the removal of the impression, being particularly rich in water, the imprints can deform but later adapt to the original shape due to the elastic properties they possess. The advantages of using alginate include the low cost, a better tolerability on the part of the patient, the ease of manipulation, the short time needed for execution, the instrumentation and the very simple execution technique and possibility of detecting a detailed impression (even in the presence of undercuts) in a single step. A comprehensive review of the current literature was conducted according to the PRISMA guidelines by accessing the NCBI PubMed database. Authors conducted a search of articles in written in English published from 2008 to 2018. All the relevant studies were included in the search with respect to the characteristics and evolution of new marine derived materials. Much progress has been made in the search for new marine derived materials. Conventional impression materials are different, and especially with the advent of digital technology, they have been suffering from a decline in research attention over the last few years. However, this type of impression material, alginates (derived from marine algae), have the advantage of being among the most used in the dental medical field.

Osteonecrosis of the jaw is an unremitting adverse outcome associated with bisphosphonate therapy in patients with multiple myeloma or bone metastases from solid tumors. Twelve patients who presented with exposed bone associated with bisphosphonates were reviewed to determine the type, dosage and duration of their bisphosphonate therapy, presenting findings, comorbidities and the event that incited the bone exposure. The discontinuation of bisphosphonate therapy has not helped reverse the presence of osteonecrosis, and the surgical manipulation of the involved site appears to worsen the underlying bone pathology. Hyperbaric oxygen, which has proven efficacious in other forms of osteonecrosis by establishing an oxygen gradient, is of no definitive benefit to patients with bisphosphonate-induced exposed bone. Antibiotic therapy is useful in controlling pain and swelling but ineffective in preventing the progression of the exposed bone. To date, prevention is the only currently possible therapeutic approach to the management of this complication.

Bisphosphonates (BPs) are the current standard of care for bone lesions in patients with multiple myeloma (MM) but they are associated with a number of side effects such as osteonecrosis of the jaw. The exact mechanisms of osteonecrosis are not elucidated, and its physiopathology is based on several hypotheses such as a decrease in bone remodeling or an inhibitory effect on angiogenesis. The aim of our study was to investigate the mechanism involved in the pathogenesis of osteonecrosis. We examined the apoptosis of circulating endothelial progenitor cells in MM subjects before and after BP treatment and in osteonecrosis patients using a flow-cytometric analysis. Our data showed an increase in endothelial cell apoptosis in MM patients after BP administration and in osteonecrosis subjects. Our study seems in agreement with the hypothesis that BPs can inhibit angiogenesis interfering with endothelial cell proliferation and survival, leading to loss of blood vessels and avascular necrosis.

Excision of neoplasm and trauma involving the anterior cranial base may often result in communication between the intracranial and extracranial compartments. Many techniques have been proposed to obtain a watertight separation. We report our 5 years of experience in the management of anterior skull base defects using a galeal-pericranial flap. Between January 2001 and April 2006, 22 patients were treated for a cranial base reconstruction at the University of Messina. Five of them presented with persistent cerebrospinal fluid (CSF) leak after previous craniofacial trauma. Ten underwent a combined maxillofacial-neurosurgical approach for the removal of a benign tumor involving the anterior skull base. Seven had severe craniofacial trauma, which required an intervention of reconstruction of the anterior skull base. In the whole series, a galeal-pericranial flap was used to separate intra- and extracranial compartments. No patients developed postoperative brain contusions or subdural-epidural blood collections. Throughout the follow-up period, there was no evidence of flap failure. In all but one patient, no postoperative CSF leak was evident. In one patient, a mild transient postoperative CSF leakage was present. There has been no recurrent CSF leak or meningitis. The follow up average of 23 months shows no incidence of infection. Even if our series does not comprise malignancies and previously irradiated patients, our data confirm the validity of the galeal- pericranial flap for the surgical management of minimal and moderately sized defects of anterior cranial base.

Bisphosphonates (BPs) are inhibitors of osteoclast‐mediated bone resorption used for the treatment of multiple myeloma (MM) patients with osteolytic lesions. Bisphosphonate‐induced osteonecrosis of the jaw (BONJ) is an infrequent drug‐caused adverse event of these agents. Long noncoding RNAs (lncRNAs) are a set of more than 200 base pairs, noncoding RNA molecules, which are critical posttranscriptional regulators of gene expression. Our study was aimed at evaluating 17 lncRNAs, whose targets were previously validated as key elements in MM, bone metabolism, and angiogenesis in MM subjects without BONJ (MM group), in MM subjects with BONJ (BONJ group), and a group of healthy controls (CTRL group). Our results demonstrated a different lncRNA profile in BONJ patients compared to MM patients and controls. Two lncRNAs (DANCR and MALAT1) were both downregulated compared to controls and MM, twelve (HOTAIR, MEG3, TP73‐AS1, HOTTIP, HIF1A‐AS2, MANTIS, CTD‐2201E18, CTD1‐2003C8, R‐471B22, RP1‐43E13, RP11‐553L6.5, and RP1‐286D6) were overexpressed in MM with BONJ, and one (H19) was upregulated compared with only MM. Two lncRNAs (JHDMD1 and MTMR9LP) had higher expression, but these differences were not statistically significant. The examined lncRNAs target several genes and metabolic pathways. An altered lncRNA signature could contribute to the onset of BONJ or have a protective action. Targeting these lncRNAs could offer a possibility for the prevention or therapy of BONJ.