Melatonin: potential functions in the oral cavity

Melatonin and oral diseases: possible therapeutic roles based on cellular mechanisms

Oral diseases, including periodontal disorders, oral cancer, periodontitis, and mucositis are the major challenges for both patients and healthcare providers. These conditions often involve inflammation, oxidative stress, and impaired cellular processes, leading to symptoms ranging from discomfort to severe debilitation. Conventional treatments for such oral diseases exhibit constraints, prompting the investigation of innovative therapeutic approaches. Considering the anti-inflammatory, anti-oxidant, and anti-cancer effects of melatonin, this study was carried out to investigate the potential protective effects of melatonin in mitigating the severity of oral diseases. Studies indicate that melatonin influences the differentiation of periodontal stem cells, inhibits oral cancer progression, reduces inflammation associated with periodontitis, and alleviates the severity of oral mucositis. Melatonin has demonstrated potential efficacy in both preclinical and clinical investigations; however, findings are frequently heterogeneous and contingent upon contextual factors. This review provides a comprehensiveoverview of current state of knowledge in this domain, elucidating the multifaceted role that melatonin may assume in combatingoral diseases. Further research should be directed toward determining the most effective dosing, timing, and administration methods for melatonin-based therapies for oral diseases.

Therapeutic applications of melatonin in disorders related to the gastrointestinal tract and control of appetite

Most animals have large amounts of the special substance melatonin, which is controlled by the light/dark cycle in the suprachiasmatic nucleus. According to what is now understood, the gastrointestinal tract (GIT) and other areas of the body are sites of melatonin production. According to recent studies, the GIT and adjacent organs depend critically on a massive amount of melatonin. Not unexpectedly, melatonin's many biological properties, such as its antioxidant, anti-inflammatory, pro-apoptotic, anti-proliferative, anti-metastasis, and antiangiogenic properties, have drawn the attention of researchers more and more. Because melatonin is an antioxidant, it produces a lot of secretions in the GIT's mucus and saliva, which shields cells from damage and promotes the development of certain GIT-related disorders. Melatonin's ability to alter cellular behavior in the GIT and other associated organs, such as the liver and pancreas, is another way that it functions. This behavior alters the secretory and metabolic activities of these cells. In this review, we attempted to shed fresh light on the many roles that melatonin plays in the various regions of the gastrointestinal tract by focusing on its activities for the first time.

Hormesis: wound healing and fibroblasts

Hormetic dose responses are reported here to occur commonly in the dermal wound healing process, with the particular focus on cell viability, proliferation, migration and collagen deposition of human and murine fibroblasts with in vitro studies. Hormetic responses were induced by a wide range of substances, including endogenous agents, pharmaceutical preparations, plant-derived extracts including many well-known dietary supplements, as well as physical stressor agents such as low-level laser treatments. Detailed mechanistic studies have identified common signaling pathways and their cross-pathway communications that mediate the hormetic dose responses. These findings complement and extend a similar comprehensive assessment concerning the occurrence of hormetic dose responses in keratinocytes. These findings demonstrate the generality of the hormetic dose response for key wound healing endpoints, suggesting that the hormesis concept has a fundamental role in wound healing, with respect to guiding strategies for experimental evaluation as well as therapeutic applications.

Effect of Non-surgical Periodontal Therapy on Salivary Melatonin Levels

Objective: Melatonin, a hormone secreted predominantly by pineal gland in a circadian manner, has antioxidant and anti-inflammatory effects. The current research is conducted to explore the influence of non-surgical periodontal therapy (NSPT) on levels of salivary melatonin in subjects with gingivitis and periodontitis. Methods: Sixty systemically healthy participants were included in this study; the groups are as follows: gingivitis (G), chronic periodontitis (CP), generalized aggressive periodontitis (GAP) and periodontally healthy (H). NSPT was applied to G group patients for 2 sessions, to CP and GAP group patients for 4 sessions. Plaque and gingival indices, probing depth (PD), bleeding on probing (BOP), and clinical attachment level (CAL) were documented at baseline and 3 months post – treatment and early morning salivary samples were collected. ELISA was used to detect melatonin levels in saliva. Pittsburgh Sleep Quality Index (PSQI) questionnaire was performed to evaluate of sleep quality of patients. Results: At baseline, significant difference in gingival index, PD, BOP and CAL values was detected among all groups (p

Assessment of dim light melatonin onset based on plasma and saliva samples

Melatonin (MELA) is a nocturnal hormone involved in the regulation of the circadian rhythm. MELA can be detected in plasma and saliva, and its salivary concentration strongly correlates with its plasma concentration. Dim light melatonin onset (DLMO) is considered to be the most accurate objective marker for assessing the circadian phase. The purpose of the study was to establish a method for the determination of MELA in plasma and saliva based on the liquid chromatography with tandem mass spectrometry (LC-MS/MS) and compare DLMO using both plasma and saliva matrices. The validation of the LC-MS/MS methods was performed in accordance with the European Medicines Agency (EMA) guideline. The study was conducted on a group of 21 volunteers, male and females, aged 26-54 years. Plasma and saliva were collected at five time points: between 20:00 and 00:00 hours. The MELA concentration was determined by the LC-MS/MS. The DLMO was considered as the point in time when MELA concentration exceeds 20 pg/mL in plasma and 7 pg/mL in saliva. The correlation coefficient between the plasma and salivary MELA concentration was r = 0.764 (p < .001). The ratio of the plasma/saliva MELA concentrations was 2.87. The mean time of the DLMO in the plasma was 21:30 ± 0:45 hours, and in the saliva was as follows: 21:34 ± 1:00 hours. The correlation between the DLMO, calculated based on the plasma and saliva MELA profiles, was r = 0.679 (p < .05). The determination of salivary MELA concentration using LC-MS/MS allows for the determination of the DLMO. Our method may be applied in clinical practice for the diagnosis and monitoring of circadian rhythm disorders.Abbreviations: CE: Collision Energy; CID: Collision-Induced Dissociation; DL: Desolvation Module; DLMO: Dim Light Melatonin Onset; EFSA: European Food Safety Authority; EMA: European Medicines Agency; ESI: electrospray ionization; HB: heat block; HPLC: high performance liquid chromatography; IS: internal standard; K₃EDTA: ethylenediaminetetraacetic acid tripotassium salt; LC-MS/MS: liquid chromatography with tandem mass spectrometry; LLE: liquid-liquid extraction; LLOQ: lower limit of quantification; MELA: melatonin; MELA-D₄: melatonin-d₄; MRM: multiple reaction monitoring; Q1: quadrupole 1; Q3: quadrupole 3; RE: relative error; RIA: radioimmunoassay; RSD: relative standard deviation; SD: standard deviation; ULOQ: upper limit of quantification.

Aging-Related Metabolic Dysfunction in the Salivary Gland: A Review of the Literature

Aging-related salivary dysfunction commonly induces the poor oral health, including decreased saliva flow and dental caries. Although the clinical significance of the salivary glands is well-known, the complex metabolic pathways contributing to the aging-dysfunction process are only beginning to be uncovered. Here, we provide a comprehensive overview of the metabolic changes in aging-mediated salivary gland dysfunction as a key aspect of oral physiology. Several metabolic neuropeptides or hormones are involved in causing or contributing to salivary gland dysfunction, including hyposalivation and age-related diseases. Thus, aging-related metabolism holds promise for early diagnosis, increased choice of therapy and the identification of new metabolic pathways that could potentially be targeted in salivary gland dysfunction.

Melatonin Treatment Alters Biological and Immunomodulatory Properties of Human Dental Pulp Mesenchymal Stem Cells via Augmented Transforming Growth Factor Beta Secretion

INTRODUCTION

Melatonin is an endogenous neurohormone with well-reported anti-inflammatory and antioxidant properties, but the direct biological and immunomodulatory effects of melatonin on human dental pulp stem cells (hDPSCs) has not been fully elucidated. The aim of this study was to evaluate the influence of melatonin on the cytocompatibility, proliferation, cell migration, odontogenic differentiation, mineralized nodule formation, and immunomodulatory properties of hDPSCs.

METHODS

To address the melatonin biological effects on hDPSCs, the cytocompatibility, proliferation, cell migration, odontogenic differentiation, mineralized nodule formation, and immunomodulatory properties of hDPSCs after melatonin treatment were evaluated. The statistical differences were evaluated using 1-way analysis of variance with the Tukey multiple comparison test.

RESULTS

We found that melatonin did not alter hDPSC immunophenotype or cell viability, even at the highest concentrations used. However, using intermediate melatonin concentrations (10-300 μmol/L), a significantly higher proliferation rate (P < .05 and P < .01) and migration of hDPSCs (P < .01) were observed. Importantly, melatonin treatment (100 μmol/L) significantly increased the secretion of the anti-inflammatory cytokine transforming growth factor beta (P < .05 and P < .01) and provoked a more robust antiproliferative effect on mitogen-stimulated T cells (P < .05). Finally, and unlike previous results found with mesenchymal stem cells from other sources, melatonin fails to induce or accelerate the spontaneous osteogenic differentiation of hDPSCs.

CONCLUSIONS

Together, these findings provide key data on the bioactivity of melatonin and its effects on hPDSC biological and immunomodulatory properties.

Circadian Profile of Salivary Melatonin Secretion in Hypoxic Ischemic Encephalopathy

PURPOSE

In the present study, the salivary melatonin secretion in the hypoxic ischemic encephalopathy (HIE) children was measured. The logit model was fitted to the data to obtain the salivary dim light melatonin onsets (DLMOs), and the results were compared with the values estimated from the classic threshold method with a linear interpolation and those previously published for the blood measurements.

MATERIALS AND METHODS

9 patients suffering from HIE aged from 65 to 80 months were included in the study. The melatonin levels were assessed by a radioimmunoassay (RIA). The diurnal melatonin secretion was estimated using a nonlinear least squares method. Student's t-test and the Mann-Whitney U test were used for the comparisons of the obtained parameters.

RESULTS

The circadian profiles of the melatonin secretion for both calculation methods do not differ statistically. The DLMO parameters obtained in the blood and saliva samples in children with hypoxic ischemic encephalopathy were similar.

Melatonin and gastrointestinal cancers: Current evidence based on underlying signaling pathways

Gastrointestinal (GI) cancers, leading causes of cancer-related deaths, have been serious challenging human diseases up to now. Because of high rates of mortality, late-stage diagnosis, metastasis to distant locations, and low effectiveness and adverse events of routine standard therapies, the quality of life and survival time are low in patients with GI cancers. Hence, many efforts need to be done to explore and find novel efficient treatments. Beneficial effects of melatonin have been reported in a wide variety of human diseases. Melatonin has antioxidant, anti-inflammatory, antimicrobial, and anticancer effects. Various studies have showed the regulatory effects of melatonin on apoptotsis, autophagy and angiogenesis; these properties result in the inhibition of invasion, migration, and proliferation of GI cancer cells in vivo and in vitro. Together, this review suggests that melatonin in combination with anticancer agents may improve the efficacy of routine medicine and survival rate of patients with cancer.

Experimental Study on the Influence of Apigenin K and Melatonin in Socket Preservation as Bone Stimulators: An Experimental Study in Beagle Dogs

The aim is to evaluate whether apigenin K and melatonin M5250 were able to stimulate bone formation after tooth extraction at one, two, and three months follow-up. Six male beagle dogs were used. Apigenin K and melatonin M5250 immersed in hemostatic collagen sponges were placed in the third and fourth premolar and the first molar extracted sockets; the second premolar was used as control. At one, two, and three months, bone core biopsies were performed, and picrosirius–hematoxylin was used for the staining process. In the first month, a higher amount of calcified bone tissue was observed in the melatonin (77.87% ± 1.2%) and apigenin K (69.81% ± 1.8%) groups than the control group (57.27% ± 0.54%), with apparent discrepancies in values between the three groups (p < 0.04). In the second month, there was a considerable improvement in the results in the areas with melatonin (79.81% ± 0.11%) than in those of apigenin K (71.65% ± 0.52%) and control (64.77% ± 0.44%) (p < 0.04). In the third month, the number of mature bone was similar to all the groups. The creation of new bone was significant in the melatonin group (82.78% ± 0.87%), followed by the apigenin K group (78.76% ± 0.43%) and the control group (57.27% ± 0.11%). From this experimental study in dogs, it can be concluded that melatonin and apigenin K can accelerate the process of mineralization of the bone matrix, and thus the creation of laminae in the early stages of healing (1 month). Less reabsorption of the post-extraction sockets can be expected with the topical application of melatonin and apigenin K. It seems that the stimulatory effects of bone healing induced by the topical application of melatonin and apigenin K are defect-size-dependent, being more evident in small defects compared to larger defects.

Melatonin-Measurement Methods and the Factors Modifying the Results. A Systematic Review of the Literature

Melatonin plays an important role in regulating the sleep-wake cycle and adaptation to environmental changes. Concentration measurements in bioliquids such as serum/plasma, saliva and urine are widely used to assess peripheral rhythm. The aim of the study was to compare methods and conditions of determinations carried out with the identification of factors potentially affecting the measurements obtained. We have identified a group of modifiable and unmodifiable factors that facilitate data interpretation. Knowledge of modifiers allows you to carefully plan the test protocol and then compare the results. There is no one universal sampling standard, because the choice of method and biofluid depends on the purpose of the study and the research group.

Melatonin as an Agent for Direct Pulp-Capping Treatment

Melatonin plays an essential role in the regulation of bone growth. The actions that melatonin exerts on odontoblasts may be similar to its action on osteoblasts. This research aimed to evaluate the pulp response to melatonin used for direct pulp capping to evaluate the antioxidant effect of melatonin administered orally and its influence on dental pulp. Direct pulp capping was performed on the upper molars of Sprague Dawley rats using melatonin or Mineral Trioxide Aggregate (MTA). The study groups were: MTA; Melatonin; MTA + Melatonin administered orally; and Melatonin + Melatonin administered orally. In the latter two groups, the animals drank water dosed with melatonin ad libitum (10 mg/100 mL). After 30 days, the animals were sacrificed, and 5 ml of blood, the kidneys, and the liver were extracted in order to evaluate oxidative stress using thiobarbituric acid reactive substances testing (TBARS). Fragments of the maxilla containing the study molars were prepared for histological evaluation. The degree of pulp inflammation and pulp necrosis, the presence of reparative dentin and dentin bridging the pulp chamber, the presence and regularity of the odontoblastic layer, and the presence of pulp fibrosis were evaluated. No significant differences were found between the four study groups for any of the studied histological variables. The oral administration of melatonin did not modify the local effects of MTA or melatonin on dental pulp, or reduce basal-level oxidative stress. The effect of melatonin on pulp is similar to that of MTA and may be used as an agent for direct pulp capping.

Potential of Melatonin as Adjuvant Therapy of Oral Cancer in the Era of Epigenomics

The wide variety of epigenetic controls available is rapidly expanding the knowledge of molecular biology even overflowing it. At the same time, it can illuminate unsuspected ways of understanding the etiology of cancer. New emerging therapeutic horizons, then, promise to overcome the current antitumor strategies need. The translational utility of this complexity is particularly welcome in oral cancer (OC), in which natural history is alarmingly disappointing due to the invasive and mutilating surgery, the high relapsing rate, the poor quality of life and the reduced survival after diagnosis. Melatonin activates protective receptor-dependent and receptor-independent processes that prevent tissue cancerisation and inhibit progressive tumor malignancy and metastasis. Related evidence has shown that melatonin pleiotropy encompasses gene expression regulation through all the three best-characterized epigenetic mechanisms: DNA methylation, chromatin modification, and non-coding RNA. OC has received less attention than other cancers despite prognosis is usually negative and there are no significant therapy improvements recorded in the past decade. However, a large research effort is being carried out to elucidate how melatonin´s machinery can prevent epigenetic insults that lead to cancer. In the light of recent findings, a comprehensive examination of biochemistry through which melatonin may reverse epigenetic aberrations in OC is an extraordinary opportunity to take a step forward in the clinical management of patients.

The effects of melatonin supplementation in adjunct with non-surgical periodontal therapy on periodontal status, serum melatonin and inflammatory markers in type 2 diabetes mellitus patients with chronic periodontitis: a double-blind, placebo-controlled trial

BACKGROUND

Diabetes mellitus (DM) and periodontitis are two common chronic diseases with bidirectional relationship. Oxidative stress plays a key role in the pathogenesis of these two diseases. The aim of this study was to investigate the effects of melatonin supplementation in adjunct with non-surgical periodontal therapy on periodontal status, serum melatonin and inflammatory markers in type 2 DM patients with chronic periodontitis (CP).

MATERIALS AND METHODS

In this double-blind clinical trial study, 50 type 2 DM patients with CP were randomly allocated to the intervention and control groups. The intervention and control groups received either 6 mg melatonin or placebo (2 tablets) once a day. Serum levels of melatonin, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), hs-C-reactive protein (hs-CRP), clinical attachment loss (CAL), pocket depth (PD), bleeding on probing (BOP) and plaque index were evaluated in all subjects pre- and post-intervention.

RESULTS

Melatonin supplementation significantly increased the mean serum levels of melatonin after intervention. The mean changes of melatonin were significantly higher in intervention group compared with control group. IL-6 and hs-CRP levels were significantly (p = 0.008 and p = 0.017, respectively) reduced in the intervention group. The mean changes of IL-6 were significantly lower in the intervention group compared with the control group (p = 0.04). In the intervention group, PD and CAL were significantly decreased after intervention (p < 0.001). There were significant differences in the mean change of PD and CAL between the intervention and control groups after intervention (p < 0.001).

CONCLUSIONS

Melatonin supplementation in adjunct with non-surgical periodontal therapy might improve inflammatory and periodontal status in T2DM with CP.

Daily melatonin administration improves osseointegration in pinealectomized rats

The hypothesis of this study was that the peri-implant bone healing of the group of pinealectomized rats would differ from the control group. The samples were subjected to immunohistochemical, microtomographic (total porosity and connectivity density), and fluorochrome (mineralized surface) analyses.

Melatonin levels in human diabetic dental pulp tissue and its effects on dental pulp cells under hyperglycaemic conditions

AIM

To investigate melatonin (MEL) levels in human dental pulp tissue (hDP) in type 2 diabetic (T2D) participants and the underlying molecular mechanisms of its effects in human dental pulp cells (hDPCs) under hyperglycaemia.

METHODOLOGY

The study included 16 healthy and 16 T2D participants who underwent vital pulp extirpation for hDP and four healthy participants undergoing third molar extraction for hDPCs analyses. MTT and NRU were used as tests for cytotoxicity. The pulp tissue levels of MEL, inducible NO synthase (iNOS) and superoxide dismutase (SOD) activity, as well as iNOS, histone acetyltransferase p300 (p300) and SOD activity levels in hDPCs incubated with MEL (0.1 and 1.0 mmol L^-1 ) under normoglycaemia and hyperglycaemia were measured by enzyme-linked immunosorbent assay. Comparisons between the two groups were made by unpaired t-tests or Mann-Whitney test whilst the chi-square test was used for dichotomous variables. To compare more groups, the Kruskal-Wallis test with Dunn's multiple comparison was used, whilst Spearman correlation was used to assess association between two variables.

RESULTS

Melatonin was decreased (124.30 ± 21.6 vs. 240.0 ± 19.1 pg mL^-1 , P < 0.01), whilst iNOS levels increased (0.92 ± 0.08 vs. 0.32 ± 0.09 ng mL^-1 , P < 0.01) in hDP from T2D compared to nondiabetic participants. In hDPCs, MEL (0.1 and 1.0 mmol L^-1 ) had no cytotoxicity. Incubation with 1.0 mmol L^-1 of MEL (24 h) decreased hyperglycaemia-induced increases of iNOS (0.34 ± 0.01 ng mL^-1 vs. 0.40 ± 0.01 ng mL^-1 , P < 0.01) and p300 (11.59 ± 0.58 ng mL^-1 vs. 16.12 ± 0.39 ng mL^-1 , P < 0.01), and also, increased SOD activity (87.11 ± 3.10% vs. 68.56 ± 3.77%, P < 0.01) to the levels comparable to the normoglycaemic; iNOS and p300 protein expression levels showed strong positive correlation under hyperglycaemia (Spearman r = 0.8242, P < 0.001).

CONCLUSION

Type 2 diabetic participants had decreased MEL in hDP. At pharmacological concentrations, MEL is not cytotoxic for hDPCs and normalizes iNOS and SOD activity levels in hyperglyceamic hDPCs suggesting its antioxidant and protective effects in human dental pulp tissue under hyperglycaemia.

Antioxidant effects of melatonin in heart tissue after induction of experimental periodontitis in rats

The aim of this study was to evaluate the effects of melatonin on the oxidative stress in heart tissues after induction of experimental periodontitis in rats. Thirty Wistar Albino male rats were divided into four groups as follows: healthy + saline solution (Hs, n = 7), healthy + melatonin (Hm, n = 7), periodontitis + saline solution (Ps, n = 8), and periodontitis + melatonin (Pm, n = 8). Experimental periodontitis was induced using a ligature placed at the gingival margin of the maxillary second molars. Melatonin was applied intraperitoneally (10 mg/kg) every day for 2 weeks. After sacrificing the rats, serum levels of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) levels, and melatonin levels were evaluated. The Pm group exhibited lower alveolar bone loss than the Ps group. Melatonin levels increased in the periodontitis groups, and the Pm group had lower MDA levels and higher GSH-Px levels than the Ps group. These findings suggest that melatonin administration reduces MDA and increases GSH-Px levels in heart tissue, and these effects may be due to its antioxidant properties. Further studies are needed to understand the effects of melatonin on the association between periodontitis and cardiovascular disease.

Effects of adjective use of melatonin and vitamin C in the treatment of chronic periodontitis: A randomized clinical trial

Background. Melatonin can eliminate free radicals and this function can be intensified byvitamin C. Melatonin and vitamin C can have synergic antioxidant effects. The aim of thisstudy was to investigate the effects of adjunctive use of melatonin and vitamin C in the non-surgical treatment of chronic periodontitis. Methods. Sixty subjects with chronic periodontitis were included in this study and randomly allocated to three groups: group 1) 20 patients received non-surgical periodontal treatment; group 2) 20 patients received non-surgical periodontal treatment with adjunctive use of melatonin; and group3) 20 patients received non-surgical periodontal treatment with combination use of melatonin + vitamin C. Clinical parameters (PD, CAL,GI) were recorded at baseline and at 3-month and 6-month intervalsafter treatment. Data were analyzed with paired t-test, one-way ANOVA andrepeated-measures ANOVA. A significant difference was assumed at P<0.05. Results. Non-surgical periodontal therapy improved PD and CAL 3 and 6 months treatment compared to baseline (P<0.001). There was a significant improvement in PD and CAL scores at 6-month interval compared to 3 months in the melatonin+ vitamin C group (P<0.05), while the differences in PD and CAL scores between the mentioned intervals were not significant between the control and melatonin groups (P>0.05). Therefore adjunctive dose of vitamin C offered an additional effect at this interval. Conclusion. Combination therapy with melatonin and vitamin C can improve the results of non-surgical periodontal therapy.

Pre-treatment with melatonin decreases abamectin induced toxicity in a nocturnal insect Spodoptera litura (Lepidoptera: Noctuidae)

AIM

Oxidative stress is an important component of the mechanism of pesticide toxicity. The aim of the present study was to investigate the time-dependent melatonin effects against abamectin-induced oxidative stress in a S.litura model. Larvae were divided into 5 different groups; (1) control group,(2) Melatonin group (4.3×10^-5M/100ml diet), (3) Abamectin group 1.5ml/L, (4) Pre-melatonin treated group (PM) (4.3×10^-5M/100ml diet) before abamectin exposure 1.5ml/L, (5) Post-melatonin treated group (TM) after abamectin exposure. Melatonin was supplemented via artificial diet in PM and TM animals during 24h.

MAIN METHODS

Midgut, fatbody, and hemolymph, were collected for the analysis of oxidative stress markers (Total ROS, GSH, nitrite, TBARS, LPO), antioxidant enzyme levels (SOD, GST, CAT, POX, APOX) in fifth instar larvae. Midgut damage was examined by using morphological analysis.

KEY FINDINGS

Our results observed that ABA group showed significant changes (p<0.001) in the ROS and carbonyl content in midgut. The increase of antioxidant enzyme levels (SOD, CAT, POX, and APOX) in midgut was led by the continuous free radical scavenger cascade of melatonin. Significant (p<0.01) increases in CAT and APOX levels were seen in the fatbody of PM and TM treated insects.

SIGNIFICANCE

In conclusion, the results of the study revealed that abamectin toxicity generates oxidative stress in the insect, while pre-melatonin treatment reduces this damage due to its antioxidant properties, especially POX levels in midgut, fatbody, and hemolymph. Therefore, indoleamine can play a vital role curtailing the abamectin toxicity in time dependent manner in S.litura.

Evaluation of Immediate Implants Augmented with Autogenous Bone/Melatonin Composite Graft in the Esthetic Zone: A Randomized Controlled Trial

PURPOSE

To evaluate the clinical and radiographic outcomes following the application of autogenous bone (ABG)/melatonin composite graft around immediate implants in the esthetic zone compared to ABG alone.

MATERIALS AND METHODS

Twenty-six patients with two nonrestorable anterior/premolar teeth were randomly classified into two equal groups. Dental implants were immediately inserted either with ABG (control group) or ABG/melatonin (test group). Outcome measures were peri-implant sulcus depth (PD), gingival index (GI), and wound healing scores. Cone beam computed tomography (CBCT) was recorded at baseline, 6, and 9 months.

RESULTS

At the end of the study, a significant difference was shown in the mean of marginal bone loss between the control group (1.91 mm ± 0.42) and the test group (0.84 mm ± 0.34) at p = 0.0001. The test group showed a significant gain in bone density, 500.73 ± 40.92, versus 420.14 ± 38.33 in the control group (p = 0.0001). There was a statistically significant difference between the control group (0.68 ± 0.42) versus the test group (0.45 ± 0.49; p = 0.044) in GI. PD was significantly reduced at the end of the study in the test group (0.42 mm ± 0.50; p = 0.002), with a similar significant improvement in the healing scores (p = 0.026).

CONCLUSION

Within the limitations of this study, immediate implants augmented with ABG/melatonin composite graft would be a valuable option in the esthetic zone.

Changes in crevicular cytokines after application of melatonin in patients with periodontal disease

Background

A clinical trial was designed to evaluate the effects of topical application of melatonin on the crevicular fluid levels of interleukins and prostaglandins and to evaluate changes in clinical parameters.

Material and Methods

A consecutive sample of 90 patients were recruited from the Health Centre of Pinos Puente in Granada, Spain and divided into 3 groups: 30 patients with diabetes and periodontal disease, who were given melatonin; 30 patients with diabetes and periodontal disease, who were given a placebo, and 30 healthy individuals with no history of systemic disease or clinical signs of periodontal disease, who were also given a placebo. The 30 patients with diabetes and periodontitis were treated with topical application of melatonin (1% orabase cream formula) for 20 days by. The rest of the patients with diabetes and periodontitis and healthy subjects were treated with a placebo of orabase cream. We measured the gingival index by exploring the percentage of standing teeth bleeding on probing. The periodontogram was performed with a Florida Probe.

Results

In the diabetic patients who were given topical melatonin, there was a statistically significant decrease in the two clinical parameters. By contrast, in diabetic patients who were given the topical placebo, there was no statistically significant variation.

Conclusions

In patients with diabetes and periodontal disease, treatment with topical melatonin was associated with a significant improvement in the gingival index and in pocket depth, and a statistically significant reduction in concentrations of interleukin-1β, interleukin-6 and prostaglandin E2 in gingival crevicular fluid.

Key words:Melatonin, periodontal disease, diabetes mellitus, interleukin-1β, interleukin-6, prostaglandin E2.

Melatonin as a potential inhibitory agent in head and neck cancer

Melatonin is a molecule secreted by the pineal gland; it is an important regulator of sleep and circadian rhythms. Through multiple interrelated mechanisms, melatonin exhibits various inhibitory properties at different stages of tumor progression. Many studies have explored the oncostatic effects of melatonin on hormone-dependent tumors. In this review, we highlight recent advances in understanding the effects of melatonin on the development of head and neck cancers, including molecular mechanisms identified through experimental and clinical observations. Because melatonin exerts a wide range of effects, melatonin may influence many mechanisms that influence the development of cancer. These include cell proliferation, apoptosis, angiogenesis, extracellular matrix remodeling through matrix metalloproteinases, and genetic polymorphism. Thus, the evidence discussed in this article will serve as a basis for basic and clinical research to promote the use of melatonin for understanding and controlling the development of head and neck cancers.

Melatonin promotes osteoblast differentiation by regulating Osterix protein stability and expression

Although the biological role of melatonin in osteogenic differentiation has been suggested, the mechanism of osteoblast differentiation remains unclear. Thus, the present study investigated the underlying molecular mechanisms based on osteoblast-specific transcription factors. We found that melatonin enhanced BMP-4-induced osteogenic differentiation and increased the expression of osteogenic markers, especially Osterix, which is an essential transcription factor for the differentiation of preosteoblasts into mature osteoblasts in the late stage of osteoblast differentiation. Melatonin treatment increased the expression of Osterix during osteoblast differentiation and stabilized its expression by the inhibition of ubiquitin-proteasome-mediated degradation of Osterix, leading to up-regulated Osterix transcriptional activity on the osteogenic promoter and promoting alkaline phosphatase activity and bone mineralization. Furthermore, treatment with protein kinase A (PKA) inhibitor H89 and protein kinase C (PKC) inhibitor Go6976 blocked the melatonin-induced transcriptional activity and phosphorylation of Osterix, indicating that melatonin regulates Osterix expression via the PKA and PKC signaling pathways. Overall, these findings suggest that melatonin directly regulates the late stage of osteoblast differentiation by enhancing Osterix expression; this provides further evidence of melatonin as a potent agent for treating osteoporosis.

Melatonin: A Review of Its Potential Functions and Effects on Dental Diseases

Melatonin is a hormone synthesised and secreted by the pineal gland and other organs. Its secretion, controlled by an endogenous circadian cycle, has been proven to exert immunological, anti-oxidant, and anti-inflammatory effects that can be beneficial in the treatment of certain dental diseases. This article is aimed at carrying out a review of the literature published about the use of melatonin in the dental field and summarising its potential effects. In this review article, an extensive search in different databases of scientific journals was performed with the objective of summarising all of the information published on melatonin use in dental diseases, focussing on periodontal diseases and dental implantology. Melatonin released in a natural way into the saliva, or added as an external treatment, may have important implications for dental disorders, such as periodontal disease, as well as in the osseointegration of dental implants, due to its anti-inflammatory and osseoconductive effects. Melatonin has demonstrated to have beneficial effects on dental pathologies, although further research is needed to understand the exact mechanisms of this molecule.

Melatonin attenuates titanium particle-induced osteolysis via activation of Wnt/β-catenin signaling pathway

Wear debris-induced inhibition of bone regeneration and extensive bone resorption were common features in peri-prosthetic osteolysis (PPO). Here, we investigated the effect of melatonin on titanium particle-stimulated osteolysis in a murine calvariae model and mouse-mesenchymal-stem cells (mMSCs) culture system. Melatonin inhibited titanium particle-induced osteolysis and increased bone formation at osteolytic sites, confirmed by radiological and histomorphometric data. Furthermore, osteoclast numbers decreased dramatically in the low- and high-melatonin administration mice, as respectively, compared with the untreated animals. Melatonin alleviated titanium particle-induced depression of osteoblastic differentiation and mineralization in mMSCs. Mechanistically, melatonin was found to reduce the degradation of β-catenin, levels of which were decreased in presence of titanium particles both in vivo and in vitro. To further ensure whether the protective effect of melatonin was mediated by the Wnt/β-catenin signaling pathway, ICG-001, a selective β-catenin inhibitor, was added to the melatonin-treated groups and was found to attenuate the effect of melatonin on mMSC mineralization. We also demonstrated that melatonin modulated the balance between receptor activator of nuclear factor kappa-B ligand and osteoprotegerin via activation of Wnt/β-catenin signaling pathway. These findings strongly suggest that melatonin represents a promising candidate in the treatment of PPO.

STATEMENT OF SIGNIFICANCE

Peri-prosthetic osteolysis, initiated by wear debris-induced inhibition of bone regeneration and extensive bone resorption, is the leading cause for implant failure and reason for revision surgery. In the current study, we demonstrated for the first time that melatonin can induce bone regeneration and reduce bone resorption at osteolytic sites caused by titanium-particle stimulation. These effects might be mediated by activating Wnt/β-catenin signaling pathway and enhancing osteogenic differentiation. Meanwhile, the ability of melatonin to modulate the balance between receptor activator of nuclear factor kappa-B ligand and osteoprotegerin mediated by Wnt/β-catenin signaling pathway, thereby suppressing osteoclastogenesis, may be implicated in the protective effects of melatonin on titanium-particle-induced bone resorption. These results suggested that melatonin can be considered as a promising therapeutic agent for the prevention and treatment of peri-prosthetic osteolysis.

Outcomes of topical applications of melatonin in implant dentistry: a systematic review

BACKGROUND

Due to its antioxidant properties and its ability to detoxify free radicals, melatonin may interfere in the function of osteoclasts and thereby inhibit bone resorption. This inhibition of bone resorption may be enhanced by a reaction of indolamine in osteoclastogenesis and this may contribute to certain benefits in implantology.

OBJECTIVE

This systematic literature review on the use of melatonin in implant dentistry aims to provide guidelines for clinicians.

MATERIALS AND METHODS

PubMed, Science Direct, ISI Web of Knowledge, and the Cochrane base databases were used to identify articles published between 1999 and 2013 on melatonin use in implant dentistry. Ten articles were selected consisting of 9 animal research studies and 1 review article, involving 60 Beagle dogs, 57 rats, and 30 rabbits and a total of 352 implants.

RESULTS

Melatonin, which is released into the saliva, has important implications in the oral cavity. To achieve dental implant stability, osseointegration involves a cascade of protein and cell apposition, vascular invasion, bone formation, and maturation. This process may be accelerated by local delivery of growth-promoting factors, as occurs with the topical application of melatonin over the implant surface.

CONCLUSIONS

The experimental evidence suggests that topical applications of melatonin may be useful in oral surgery and implant dentistry, increasing bone-to-implant contact values and new bone formation, and so improving the success and long-term survival of implant treatments.

Osseoinductive elements around immediate implants for better osteointegration: a pilot study in foxhound dogs

OBJECTIVE

The aim of this study was to evaluate the effects on osseointegration of topical applications of melatonin vs. vitamin D over surfaces of immediate implants.

MATERIALS AND METHODS

Mandibular premolar distal roots (P₂ , P₃ , P₄ ) were extracted bilaterally from six American Foxhound dogs. Three conical immediate implants were randomly placed bilaterally in each mandible. Three randomized groups were created: melatonin 5% test group (MI), vitamin D 10% test group (DI), and Control group implants (CI). Block sections were obtained after 12 weeks and processed for mineralized ground sectioning. Bone-to-implant contact (total BIC), new bone formation (NBF), inter-thread bone (ITB), and histological linear measurements (HLM) were assessed.

RESULTS

At 12 weeks, all implants were clinically stable and histologically osseointegrated. Total BIC values were 49.20 ± 3.26 for the MI group, 49.86 ± 1.89 for DI group and 45.78 ± 4.21 for the CI group (P < 0.018) with statistically significant difference between the three groups. BIC percentage were 42.44 ± 2.18 for MI, 44.56 ± 1.08 for DI, and 41.95 ± 3.34 for CI groups respectively (P > 0.05). Inter-thread bone formation values were MI 17.56 ± 2.01, for DI 19.87 ± 0.92, and CI 14.56 ± 1.24 (P > 0.05). Statistically significant differences in peri-implant new bone formation were found between the three groups: MI 28.76 ± 1.98, DI 32.56 ± 1.11 and CI 25.43 ± 4.67, respectively (P < 0.045). Linear measurements showed that the MI group showed significantly less lingual crestal bone loss (CBL) (MI 0.59 ± 0.71), compared to DI (0.91 ± 1.21) and CI (0.93 ± 1.21) (P < 0.042), and less lingual peri-implant mucosa (PIM) (MI 3.11 ± 1.34),(DI 3.25 ± 0.18 compared with CI 3.54 ± 1.81 (P = 0.429). Linear measurements of buccal CBL showed significantly less buccal bone loss in test DI (0.36 ± 0.12) than CI (1.34 ± 1.23) and MI (1.11 ± 1.38) (P = 0.078).

CONCLUSIONS

Within the limitations of this animal study, topical applications of 5% Melatonin or 10% vitamin D improved bone formation around implants placed immediately after extraction and helped to reduce CBL after 12 weeks osseointegration.

Malondialdehyde, superoxide dismutase and melatonin levels in gingival crevicular fluid of aggressive and chronic periodontitis patients

BACKGROUND

The aim of this study was to investigate malondialdehyde (MDA), superoxide dismutase (SOD) and melatonin levels in the gingival crevicular fluid (GCF) of patients with chronic periodontitis (CP) and generalized aggressive periodontitis (GAgP) as biomarkers for oxidative stress.

METHODS

The study comprised 65 subjects: 15 healthy individuals, 25 CP patients and 25 GAgP patients. Plaque index, gingival index, pocket depth, clinical attachment level measurements and GCF samples were obtained from all subjects. MDA, SOD and melatonin levels were determined utilizing enzyme-linked immunosorbent assay.

RESULTS

GCF-MDA levels were significantly higher in the GAgP group compared to the CP and control groups (p < 0.001) and significantly higher in the CP group than the C group (p < 0.001). SOD and melatonin GCF levels were significantly higher in the control than the GAgP and CP groups (p < 0.05), and significantly lower in the GAgP than the CP group (p < 0.05). The CP group demonstrated a significant negative correlation between GCF-MDA and melatonin concentrations. A positive correlation was observed between SOD and CAL in the CP group and PD in the GAgP group.

CONCLUSIONS

MDA, melatonin and SOD could be considered as biomarkers for oxidative stress in periodontal diseases and might be useful diagnostic aids in distinguishing CP and GAgP patients.

Melatonin localization in human salivary glands

BACKGROUND

Circulating melatonin is believed to reach body fluids by crossing passively the cell membranes, but alternative ways for melatonin transport also are hypothesized. This investigation was carried out to furnish ultrastructural evidences for melatonin transport by salivary gland cells in order to indicate plausible routes by which circulating melatonin can reach saliva.

METHODS

Bioptic samples of parotid, submandibular and labial glands were processed for the electron microscopy and treated to demonstrate melatonin reactivity by the immunogold staining method.

RESULTS AND CONCLUSIONS

The preferential sites of melatonin reactivity were the granules and vesicles of serous cells. Our results suggested that the acinar cells are able to store melatonin and that the hormone can be released into saliva through granule and vesicle exocytosis. The quantitative evaluation of labelling showed that the parotid gland is the most involved in the release of melatonin in saliva.

The Effect of Melatonin on Bone Loss, Diabetic Control, and Apoptosis in Rats With Diabetes With Ligature-Induced Periodontitis

BACKGROUND

The aim of this study examines the effect of systemic melatonin administration on proinflammatory cytokine levels, apoptosis, alveolar bone loss (ABL), lipid metabolism, and diabetic control in in rats with diabetes mellitus (DM) and ligature-induced periodontitis.

METHODS

Fifty-two male Wistar rats were used in this study. Study groups were as follows: 1) non-ligated control (NL, n = 6); 2) streptozotocin (STZ, n = 8); 3) STZ and melatonin (STZ+Mel, n = 8); 4) ligature (L, n = 6); 5) ligature and melatonin (L+Mel, n = 8); 6) STZ and ligature (STZ+L, n = 8); and 7) STZ, ligature, and melatonin (STZ+L+Mel, n = 8). DM was induced by intraperitoneal injection of a single dose of STZ (60 mg/kg). Melatonin was administered by intraperitoneal injection of a dose of 10 mg/kg/day for 4 weeks. Silk ligatures were placed subgingivally around the mandibular right first molars. The study period was 4 weeks, and animals were sacrificed at the end of 4 weeks. Morphometric analysis of bone loss was performed. Tissues were histopathologically examined. Inducible nitric oxide synthase (iNOS) and B-cell lymphoma-2-associated X (bax) protein expressions, serum interleukin (IL)-1β levels, and tartrate-resistant acid phosphatase-positive (TRAP+) osteoclast numbers were also evaluated.

RESULTS

After 4 weeks, the highest ABL was observed in the STZ+L group, and the difference was significant (P <0.05). Systemically administered melatonin significantly decreased ABL in the STZ+L+Mel group compared with that in the STZ+L group (P <0.05). TRAP+ osteoclast numbers were the highest in the STZ+L group, and melatonin significantly decreased osteoclast numbers (P <0.05) but had no effect on iNOS, IL-1β, or bax levels.

CONCLUSIONS

Within the limits of this study, it can be concluded that systemic melatonin treatment may decrease osteoclastic activity and reduce ABL in the model using rats with DM.

Use of melatonin in oral health and as dental premedication

Anxiety is a common problem in dentistry which could affect the correct treatment and involve failure. Oral premedication is needed to treat several anxious patients. Many people are so highly anxious that oral sedation is not effective and need to be under deep sedation or even general anaesthesia in order to receive dental care. In these patients, due to a high level of anxiety, even the insertion of an intravenous catheter can be difficult. Benzodiazepines have been the most commonly used anxiolytic in these cases, but many may be associated with paradoxical reactions. Melatonin has a good potential to be used in this field as alternative to benzodiazepines because it may induce a natural sleepiness and improve sedation. The purpose of this paper was to summarize what is known about the use of melatonin in oral health and as dental premedication in anxious dental patients. Databases were searched for the relevant published literature to 30 April 2015. The following search items were used in various combinations: melatonin, premedication, anxiety, dental, sedation and anaesthesia. Few articles were found about this aspect, and the use of melatonin is still a controversial aspect in dental field. More detailed/specific studies are necessary to extend the therapeutic possibilities of melatonin as premedication in dentistry.

Melatonin as a candidate therapeutic drug for protecting bone cells from chlorhexidine-induced damage

BACKGROUND

Melatonin was proposed for use in periodontitis and peri-implantitis therapy due to its bone-supportive effects. This issue is of interest because standard adjuvant antiseptics, namely chlorhexidine (CHX), prove damaging for osteoblasts. Thus, the aim of this study is to investigate if melatonin is suitable as an auxiliary agent for protecting osteoblasts from CHX damage.

METHODS

MC3T3 osteoblast response was determined following administration of various CHX concentrations in the absence or presence of melatonin. Osteoblast morphology was evaluated, total reactive oxygen species (ROS) and superoxide levels were quantified, ratios of apoptotic and necrotic cells were identified by flow cytometry, metabolic activity of remaining cells was assessed, and effects were calculated with repeated measures analysis and post hoc P value adjustment.

RESULTS

CHX led to poor morphology, increased total ROS and superoxide levels, and rigorously diminished the number of vital and metabolic active osteoblasts in a concentration-dependent manner. However, simultaneous melatonin supply supported cell morphogenesis and growth, reduced ROS and superoxide generation, shifted the percentage of CHX-damaged cells from necrotic/late to early apoptotic events, and modulated metabolic activity in osteoblasts.

CONCLUSION

These data reveal that melatonin protects osteoblasts in the CHX context, thereby implicating melatonin as a promising drug in periodontitis and peri-implantitis treatment.

The antioxidant master glutathione and periodontal health

Glutathione, considered to be the master antioxidant (AO), is the most-important redox regulator that controls inflammatory processes, and thus damage to the periodontium. Periodontitis patients have reduced total AO capacity in whole saliva, and lower concentrations of reduced glutathione (GSH) in serum and gingival crevicular fluid, and periodontal therapy restores the redox balance. Therapeutic considerations for the adjunctive use of glutathione in management of periodontitis, in limiting the tissue damage associated with oxidative stress, and enhancing wound healing cannot be underestimated, but need to be evaluated further through multi-centered randomized controlled trials.

Evaluating the Oxidative Stress in Inflammation: Role of Melatonin

Oxygen is used by eukaryotic cells for metabolic transformations and energy production in mitochondria. Under physiological conditions, there is a constant endogenous production of intermediates of reactive oxygen (ROI) and nitrogen species (RNI) that interact as signaling molecules in physiological mechanisms. When these species are not eliminated by antioxidants or are produced in excess, oxidative stress arises. Oxidative stress can damage proteins, lipids, DNA, and organelles. It is a process directly linked to inflammation; in fact, inflammatory cells secrete a large number of cytokines and chemokines responsible for the production of ROI and RNI in phagocytic and nonphagocytic cells through the activation of protein kinases signaling. Currently, there is a wide variety of diseases capable of producing inflammatory manifestations. While, in the short term, most of these diseases are not fatal they have a major impact on life quality. Since there is a direct relationship between chronic inflammation and many emerging disorders like cancer, oral diseases, kidney diseases, fibromyalgia, gastrointestinal chronic diseases or rheumatics diseases, the aim of this review is to describe the use and role of melatonin, a hormone secreted by the pineal gland, that works directly and indirectly as a free radical scavenger, like a potent antioxidant.

Potential role of melatonin in prevention and treatment of oral carcinoma

Melatonin, a hormone secreted mainly by pineal gland has been found to have antioxidant and anti-inflammatory properties in the oral cavity where it reaches through saliva. These properties have been found to be beneficial in certain oral pathologies including periodontal diseases, herpes viral infections and Candida, local inflammatory processes, xerostomia, oral ulcers and oral cancer. The objective of this review is to discuss the mechanism of action and potential role of melatonin as a preventive and curative agent for oral cancer. an extensive review of databases like pubmed, medline, science direct and Cochrane reviews was conducted to find articles related to beneficial actions of melatonin in human body with focus on cancers. Numerous studies both in-vitro and in-vivo had shown promising results regarding role of melatonin as anti-carcinogenic agent. Melatonin may play a role in protecting the oral cavity from tissue damage caused by oxidative stress. The experimental evidence suggests that melatonin may have utility in the treatment of several common cancers of the body. However, more specific studies are necessary to extend the therapeutic possibilities to oral carcinoma.

Effect of melatonin on human dental papilla cells

Melatonin regulates a variety of biological processes, which are the control of circadian rhythms, regulation of seasonal reproductive function and body temperature, free radical scavenging and so on. Our previous studies have shown that various cells exist in human and mouse tooth germs that express the melatonin 1a receptor (Mel1aR). However, little is known about the effects of melatonin on tooth development and growth. The present study was performed to examine the possibility that melatonin might exert its influence on tooth development. DP-805 cells, a human dental papilla cell line, were shown to express Mel1aR. Expression levels of mRNA for Mel1aR in DP-805 cells increased until 3 days after reaching confluence and decreased thereafter. Real-time reverse transcription-polymerase chain reaction showed that melatonin increased the expression of mRNAs for osteopontin (OPN), osteocalcin (OCN), bone sialoprotein (BSP), dentin matrix protein-1 (DMP-1) and dentin sialophosphoprotin (DSPP). Melatonin also enhanced the mineralized matrix formation in DP-805 cell cultures in a dose-dependent manner. These results strongly suggest that melatonin may play a physiological role in tooth development/growth by regulating the cellular function of odontogenic cells in tooth germs.

Melatonin effects on bone: potential use for the prevention and treatment for osteopenia, osteoporosis, and periodontal disease and for use in bone-grafting procedures

An important role for melatonin in bone formation and restructuring has emerged, and studies demonstrate the multiple mechanisms for these beneficial actions. Statistical analysis shows that even with existing osteoporotic therapies, bone-related disease, and mortality are on the rise, creating a huge financial burden for societies worldwide. These findings suggest that novel alternatives need to be developed to either prevent or reverse bone loss to combat osteoporosis-related fractures. The focus of this review describes melatonin's role in bone physiology and discusses how disruption of melatonin rhythms by light exposure at night, shift work, and disease can adversely impact on bone. The signal transduction mechanisms underlying osteoblast and osteoclast differentiation and coupling with one another are discussed with a focus on how melatonin, through the regulation of RANKL and osteoprotegerin synthesis and release from osteoblasts, can induce osteoblastogenesis while inhibiting osteoclastogenesis. Also, melatonin's free-radical scavenging and antioxidant properties of this indoleamine are discussed as yet an additional mechanism by which melatonin can maintain one's bone health, especially oral health. The clinical use for melatonin in bone-grafting procedures, in reversing bone loss due to osteopenia and osteoporosis, and in managing periodontal disease is discussed.

Melatonin regulates human bone sialoprotein gene transcription

Melatonin is produced by the pineal gland and regulates various physiological processes including osteoblast differentiation and bone formation. Bone sialoprotein (BSP) is a mineralized connective tissue-specific protein expressed in the early stage of cementum and bone mineralization. To elucidate the effects of melatonin on human BSP gene expression, we utilized human Saos2 osteoblast-like cells. Melatonin (100 nM) increased the level of BSP mRNA at 3 h, and the level became maximal at 12 and 24 h. We then investigated the melatonin-induced transcriptional activity of luciferase constructs (between -84LUC and -868LUC) including different lengths of the human BSP gene promoter transfected into Saos2 cells. The effects of melatonin abrogated in constructs included 2-bp mutations in the two cAMP response elements (CRE1 and CRE2). The effects of melatonin were suppressed by protein kinase A, tyrosine kinase, ERK1/2 and phosphatidylinositol 3-kinase inhibitors. Gel mobility shift assays showed that melatonin increased the binding of nuclear proteins to CRE1 and CRE2, and antibodies against CRE binding protein 1 (CREB1), phospho-CREB1, c-Fos, c-Jun, JunD and Fra2 disrupted CRE1 and CRE2 protein complex formation. These data indicate that melatonin induces BSP transcription via the CRE1 and CRE2 elements in the human BSP gene promoter. (J Oral Sci 56, 67-76, 2014).