Effect of topical application of melatonin to the gingiva on salivary osteoprotegerin, RANKL and melatonin levels in patients with diabetes and periodontal disease.

This cross-section study was designed to assess the effect of topical application of melatonin to the gingiva on salivary RANKL, osteoprotegrin (OPG) and melatonin levels as well as plasma melatonin in 30 patients with diabetes and periodontal disease and in a control group of 30 healthy subjects. Salivary RANKL and OPG were measured by enzyme-linked immunosorbent assay and salivary and plasma melatonin by radioimmunoassay using commercial kits. Periodontograms were performed using the Florida Probe(®). Diabetic patients were treated with topical application of melatonin (1% orabase cream formula) once daily for 20 days. Patients with diabetes showed significantly higher mean levels of salivary RANKL than healthy subjects as well as significantly lower values of salivary OPG and salivary and plasma melatonin. After treatment with melatonin, there was a statistically significant decrease of the gingival index, pocket depth and salivary levels of RANKL, and a significant rise in salivary values of OPG. Changes of salivary OPG levels before and after topical melatonin treatment correlated significantly with changes in the gingival index and pocket depth. Treatment with topical melatonin was associated with an improvement in the gingival index and pocket depth, a reduction in salivary concentrations of RANKL and increase in salivary concentrations of OPG, which indicates that melatonin has a favorable effect in slowing osteoclastogenesis, improving the quality of alveolar bone and preventing the progression of periodontal disease.

The impact of vaccination upon dental clinic avoidance and the cessation of individual protection measures.

The aim of this study was to analyze the evolution of germ aversion, to perceived infectability and to the fear of COVID-19 from the beginning of the pandemic until the arrival of the vaccines. A repeated measures design was used with three time points during the pandemic. The survey consisted of: Scale of perceived vulnerability to disease; Scale of fear of COVID-19; They were asked if they were vaccinated and if that vaccination is complete. They were asked if they would avoid the dental clinic through fear of COVID-19; and if they have reduced preventive practice in response to COVID-19. A T0-T1 increase in perceived infectability and germ aversion was reported. However, fear of COVID-19 decreased at T1-T2. The vaccinated experienced a greater reduction than the unvaccinated and a greater relaxation of their preventive practice. The frequency of dental avoidance decreased in the vaccinated group from T1 to T2 by 68.3% while in the non-vaccinated this reduction was only 4.9%; X 2 = 18.58 (p < 0.01). In summary, vaccination has had an impact in the reduction of perceived infectability and in reducing fear of COVID-19. Nevertheless, germ aversion has remained stable and independent of vaccination. Empirical support is found for the affirmation that vaccination can reduce certain preventive behavior and dental avoidance.

Action of melatonin on squamous cell carcinoma and other tumors of the oral cavity (Review).

Melatonin (MLT; N-acetyl-5-metoxy-tryptamine) is a hormone that is principally synthesized in the pineal gland. MLT has been shown to exhibit a variety of functions. The hormone, which is a free radical scavenger, plays an immunomodulatory role, stimulates the proliferation and synthesis of type I collagen and promotes bone formation. Moreover, MLT exerts oncostatic activity through several biological mechanisms, including antiproliferative functions, stimulation of anticancer immunity, modulation of oncogene expression and anti-inflammatory, antioxidant and antiangiogenic effects. In addition, MLT inhibits human cancer cell growth in culture, and previous clinical studies have also confirmed its anticancer properties in vivo. With regard to the underlying mechanisms of MLT in tumor processes, including oral cavity tumors such as epidermoid carcinoma, knowledge of the role played by the MT1 and 2 membrane receptors, MT3 and the calmodulin cytosolic binding sites, as well as the nuclear receptors of the RZR/ROR family, is increasing. It has been hypothesized that exogenous restoration of MT1 (MTNR1A) expression inhibits the growth of oral squamous cell carcinoma cells lacking the expression of the receptor. The tumor suppressing functions of MLT and the presence of the MT1 receptor in various tumors indicate that the receptor may play a pivotal role in oral carcinogenesis. The current review discusses the clinical significance of MLT in oral cancer.

A retrospective study of the risk factors for ridge expansion with self-tapping osteotomes in dental implant surgery.

PURPOSE: To analyze the risk factors associated with the survival of self-threading implants placed with the ridge expansion technique using self-tapping osteotomes after at least 24 months. MATERIALS AND METHODS: This retrospective study followed patients for at least 2 years in whom implants had been inserted by means of the ridge expansion technique. The patient was taken as the unit of analysis, and the loss of any implant as a result of mobility at any time during the follow-up period was considered as a failure. A number of patient variables were recorded: sociodemographic (age/sex), anatomical (bone quantity/quality, expansion zone), infection history (prior antibiotic therapy for active infection), prosthodontic (type of provisional prosthesis and type of definitive rehabilitation), and surgical (number of surgical stages, the use of biomaterials or atraumatic maxillary sinus elevation). Risk factors were expressed as values of relative risk (RR) and the odds ratio. RESULTS: Seventy-four patients (157 implants) were followed over a mean period of 38.8 ± 7.7 months. Most patients (91.9%) did not lose any implants, and failures occurred mainly after implant loading (5.4%). Sociodemographic factors (sex and age) were not associated with a significant risk of implant failure. However, the existence of previous local infection (RR = 34.0), the use of an immediate fixed provisional prosthesis (RR = 15.0), and type D3 bone (RR = 5.1) were seen to be the main risk factors involved in this technique for the period assessed. CONCLUSIONS: The risk of failure when implants are placed using self-tapping osteotomes was highest in patients who had active local infection; immediate provisionalization and less dense bone were also associated with additional risk of failure.

Role of melatonin in cancer treatment.

Melatonin has revealed itself to be a pleiotropic and multitasking molecule. The mechanisms that control its synthesis and the biological clock processes that modulate the circadian production of melatonin in the pineal gland have been well-characterized. A feature that characterizes melatonin is the variety of mechanisms it employs to modulate the physiology and molecular biology of cells. Research has implicated the pineal gland and melatonin in the processes of both aging and age-related diseases. The decline in the production of melatonin with age is thought to contribute to immunosenescence and potential development of neoplastic diseases. Melatonin has been shown to inhibit growth of different tumors under both in vitro and in vivo conditions. There is evidence that the administration of melatonin alone or in combination with interleukin-2 in conjunction with chemoradiotherapy and/or supportive care in cancer patients with advanced solid tumors, has been associated with improved outcomes of tumor regression and survival. Moreover, chemotherapy has been shown to be better tolerated in patients treated with melatonin.