MicroRNAs Function in Dental Stem Cells as a Promising Biomarker and Therapeutic Target for Dental Diseases.

Undifferentiated, highly proliferative, clonogenic, and self-renewing dental stem cells have paved the way for novel approaches to mending cleft palates, rebuilding lost jawbone and periodontal tissue, and, most significantly, recreating lost teeth. New treatment techniques may be guided by a better understanding of these cells and their potential in terms of the specificity of the regenerative response. MicroRNAs have been recognized as an essential component in stem cell biology due to their role as epigenetic regulators of the processes that determine stem cell destiny. MicroRNAs have been proven to be crucial in a wide variety of molecular and biological processes, including apoptosis, cell proliferation, migration, and necrocytosis. MicroRNAs have been recognized to control protein translation, messenger RNA stability, and transcription and have been reported to play essential roles in dental stem cell biology, including the differentiation of dental stem cells, the immunological response, apoptosis, and the inflammation of the dental pulp. Because microRNAs increase dental stem cell differentiation, they may be used in regenerative medicine to either preserve the stem cell phenotype or to aid in the development of tooth tissue. The development of novel biomarkers and therapies for dental illnesses relies heavily on progress made in our knowledge of the roles played by microRNAs in regulating dental stem cells. In this article, we discuss how dental stem cells and their associated microRNAs may be used to cure dental illness.

Emerging role of exosomes in craniofacial and dental applications.

Exosomes, a specific subgroup of extracellular vesicles that are secreted by cells, have been recognized as important mediators of intercellular communication. They participate in a diverse range of physiological and pathological processes. Given the capability of exosomes to carry molecular cargos and transfer bioactive components, exosome-based disease diagnosis and therapeutics have been extensively studied over the past few decades. Herein, we highlight the emerging applications of exosomes as biomarkers and therapeutic agents in the craniofacial and dental field. Moreover, we discuss the current challenges and future perspectives of exosomes in clinical applications.

Novel molecular cues for dental defects in hypophosphatasia.

Mineralization disorders with a broad range of etiological factors represent a huge challenge in dental diagnosis and therapy. Hypophosphatasia (HPP) belongs to the rare diseases affecting predominantly mineralized tissues, bones and teeth, and occurs due to mutations in the ALPL gene, which encodes tissue-nonspecific alkaline phosphatase (TNAP). Here we analyzed stem cells from bone marrow (BMSCs), dental pulp (DPSCs) and periodontal ligament (PDLSCs) in the absence and presence of efficient TNAP inhibitors. The differentiation capacity, expression of surface markers, and gene expression patterns of donor-matched dental cells were compared during this in vitro study. Differentiation assays showed efficient osteogenic but low adipogenic differentiation (aD) capacity of PDLSCs and DPSCs. TNAP inhibitor treatment completely abolished the mineralization process during osteogenic differentiation (oD). RNA-seq analysis in PDLSCs, comparing oD with and without TNAP inhibitor levamisole, showed clustered regulation of candidate molecular mechanisms that putatively impaired osteogenesis and mineralization, disequilibrated ECM production and turnover, and propagated inflammation. Combined alteration of cementum formation, mineralization, and elastic attachment of teeth to cementum via elastic fibers may explain dental key problems in HPP. Using this in vitro model of TNAP deficiency in DPSCs and PDLSCs, we provide novel putative target areas for research on molecular cues for specific dental problems in HPP.

Salivary pH and flow rate in menopausal women.

OBJECTIVE: This study aims at determining pH and Flow Rate (FR) of Unstimulated Whole Saliva (UWS) in a sample of 120 ♀ (60 menopausal women and 60 healthy fertile women with similar mean age); detecting the DMFT index (Decayed, Missing, Filled Teeth index) and evaluating any correlations between pH, FR, age and DMFT. PATIENTS AND METHODS: Concerning the day before sample collection, patients were advised to keep a relaxed attitude and not to practice sports. They were also told to not eat or drink during the hour preceding sampling procedures. Saliva was collected via "spitting" method. Each sampling session started at 11:00 a.m., lasted for 5 minutes and used a pre-weighed, dry, deionized and sterile test tube. The procedure took place under controlled environmental temperature and humidity conditions (means 23.27°C; 60.08%). FR was evaluated via weighing technique and pH was measured with a portable pH-meter. RESULTS: There was a minimal but significant pH difference (0.11; p<0.05) between menopausal women (6.75 ± 0.34) and fertile women (6.86 ± 0.24); and a FR difference (0.19; p<0.0001) between menopausal women (0.29 ± 0.17 mL/min) and fertile women (0.48 ± 0.19 mL/min). Correlation (R2) between pH and age was 0.0135 for fertile women and 0.0055 for menopausal women; while the correlation between FR and age was 0.0673 for fertile women and 0.139 for menopausal women. Mean DMFT was 11.93 ± 7.14 in menopausal women and 12.23 ± 6.37 in fertile women. CONCLUSIONS: We observed a minimal decrease in pH and a decrease in FR in menopausal women. Further studies will be needed to investigate the possible role of other environmental and individual variables in the determination of such values.

Formation of papillary mucosa folds and enhancement of epithelial barrier in odontogenic sinusitis.

BACKGROUND: Odontogenic sinusitis (OS) presents more satisfactory therapeutic effect after endoscopic surgery compared with chronic rhinosinusitis (CRS) of other origin. The aim of the present study was to investigate the clinical characteristics, morphological features, and epithelial barrier function of sinus mucosa of OS and discuss the possible relationship with good prognosis. METHODS: A total of 25 subjects with OS, 7 CRS without nasal polyps (CRSsNP), 10 CRS with nasal polyps (CRSwNP), and 9 control subjects were recruited. The biopsy specimens were stained with hematoxylin and eosin for general observation of cytomorphologic features. Epithelial tight junctions (TJs) protein claudin-4 expression was determined to evaluate the epithelial barrier integrity by using immunofluorescence and Image-Pro Plus software analysis. The representative cytokine profiles regarding T helper 1 (Th1) (interferon [IFN]-γ), Th2 (interleukin [IL]-5), and Th17 (IL-17) were examined by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Extensively small papillary protrusions could be seen in the maxillary sinus mucosa of OS patients under nasal endoscopy, similar to the morphological behavior, which also presented as papillary folds in the surface of the epithelium. The epithelium in OS kept an increased claudin-4 expression compared with that seen in CRSsNP, CRSwNP, and control subjects. The inflammatory pattern analysis demonstrated that OS belonged to the lymphocyte and plasma cell-dominant cellular phenotypes, whereas IL-17 was dominant compared with IFN-γ as well as IL-5. CONCLUSION: The odontogenic infections might induce the formation of papillary mucosa folds and enhance the epithelial TJ barrier function. OS exhibited as lymphocyte and plasma cell-dominant cellular phenotypes and Th17 cytokine profiles.

Advanced glycation end products (AGEs) in oral pathology.

OBJECTIVE: Maillard advanced glycation end products (AGEs) are connected with high dry temperature food processing, color and flavor modification of food products. Oral cavity pathology is strongly influenced by dietary intake. The aim of the present paper is to update current data regarding the sources and metabolism of AGEs, their impact on oral cavity tissues, to discuss and suggest new approaches for the early diagnosis and efficient treatment of AGEs-related oral pathology. DESIGN: This paper is a narrative review of the studies discussing AGEs and mainly the dietary AGEs (dAGEs) sources, metabolism, linkage to general diseases, and specifically the oral cavity pathology. The authors used "PUBMED" and MeSH for the finding of English written and published articles concerning AGEs. There were used the next keywords association: "advanced glycation end products- AGEs" AND "Maillard products", "AGEs" AND "diet-related disease, "AGEs" AND "salivary biosensor", "AGEs" AND "metabolic syndrome AGEs", "AGEs" AND "oral pathology", "AGEs" AND "dentin AGEs" OR "periodontal AGEs", "AGEs" AND "diagnosis and monitoring". The authors used free full-text articles to determine the etiology and physiopathology of AGEs, their association with general diseases and oral cavity disease, assessment methods used in biofluids and tissues, AGEs prevention and treatment approaches. Articles concerning AGEs etiology, metabolism and effect in the human body and specific implication in oral pathology were selected. There were no exclusion criteria in what concerns the study design. Studies in other language than English and articles abstracts were excluded. Criteria of inclusion were free full-text articles written in English. Equally human and animal model studies were included. Regarding the date of publication, all subjects concerning glycation products after 1953 (first published article) were included. RESULTS: Evidence show that AGEs are responsible for inducing low intensity chronic inflammation and thereby, for initiating and/or aggravating chronic diseases. Nowadays, research has demonstrated a significant association between AGEs and dental or periodontal pathology. Moreover, salivary AGEs are consistent with the levels of AGEs in other biological fluids and are correlated with the general and oral pathology. CONCLUSIONS: Assessment of salivary AGEs could be a reliable tool for early diagnosis and monitoring diet-related disease.

Combined analysis of the salivary microbiome and host defence peptides predicts dental disease.

Understanding the triad of host response, microbiome and disease status is potentially informative for disease prediction, prevention, early intervention and treatment. Using longitudinal assessment of saliva and disease status, we demonstrated that partial least squares modelling of microbial, immunological and clinical measures, grouped children according to future dental disease status. Saliva was collected and dental health assessed in 33 children aged 4 years, and again 1-year later. The composition of the salivary microbiome was assessed and host defence peptides in saliva were quantified. Principal component analysis of the salivary microbiome indicated that children clustered by age and not disease status. Similarly, changes in salivary host defence peptides occurred with age and not in response to, or preceding dental caries. Partial least squares modelling of microbial, immunological and clinical baseline measures clustered children according to future dental disease status. These data demonstrate that isolated evaluation of the salivary microbiome or host response failed to predict dental disease. In contrast, combined assessment of both host response together with the microbiome revealed clusters of health and disease. This type of approach is potentially relevant to myriad diseases that are modified by host-microbiome interactions.

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.

Bone impairment in primary hyperoxaluria: a review.

Deposition of calcium oxalate crystals in the kidney and bone is a hallmark of primary hyperoxaluria (PH). Since the bone compartment can store massive amounts of oxalate, patients present with recurrent low-trauma fractures, bone deformations, severe bone pains, and specific oxalate osteopathy on X-ray. Bone biopsy from the iliac crest displays specific features such as oxalate crystals surrounded by a granulomatous reaction corresponding to an invasion of bone surface by macrophages. The objective of this manuscript is therefore to provide an overview of bone impairment in PH, by reviewing the current literature on bone and dental symptoms as well as imaging techniques used for assessing bone disease.

Evaluation of the saliva cortisol levels in patients under prosthetic treatment due to functional disorders of the masticatory organ.

One of the main etiological factors of the stomatognathic system dysfunction is stress and psychoemotional disorders. During stressful situations, there is an increase in the level of cortisol, the so-called stress hormone. Literature data indicate the existence of a correlation between blood cortisol levels and its amount in the saliva. This spurred an inspiration to undertake open, non-randomised studies, the objective of which was to conduct a comparative assessment of the saliva cortisol levels in patients with functional disorders of the masticatory system and in healthy volunteers, as well as to compare the results of cortisol levels with the results of survey-based tests with the use of Endler and Parker's CISS survey. Cortisol level was assessed due to its association with stress present in the body as one of the primary etiological factors of the stomatognathic system dysfunction, and hence the association of elevated cortisol levels assessed in the morning with the occurrence of dysfunctions of the stomatognathic system. The subject of the study is a group of 30 patients, of both sexes, aged between 20 and 46, who reported to the Dental Prosthetic Out-Patient Clinic of the Institute of Dentistry, Jagiellonian University in Cracow, for prosthetic treatment due to the painful form of functional masticatory organ disorders. The control group consisted of 30 subjects, aged between 19 and 41, in whom dysfunctions of the stomatognathic system were excluded. Collection of saliva for testing was performed at a fixed hour (9 am) into plastic test tubes with a stopper. Immediately after collection, the saliva was frozen at the temperature of -18 °C. The assessment of the cortisol levels was conducted by the high performance liquid chromatography (HPLC) with UV detection at the Department of Analytical Chemistry, Faculty of Pharmacy, Department of Laboratory Medicine of the Gdansk Medical University. Moreover, a 20-minute psychological test was conducted with the use of the CISS (coping inventory for stressful situations) survey in order to assess the patients in terms of their abilities to cope with stressful situations. The results obtained were submitted to a statistical analysis based on the conventional calculation procedures. The test group revealed significantly higher cortisol levels compared with the results obtained by the control group. The findings of the CISS survey confirmed the predominance of the emotion-focused strategy of coping with stressful situations in the test group. The results support the view that the psychoemotional factor is, to a considerable extent, conducive to the development of functional disorders. The elevated cortisol levels in patients with psychological disorders concur with the findings by other authors. The results obtained confirm that psychoemotional disorders may be one of the etiological factors of the stomatognathic system dysfunctions. The CISS survey, which was not used in similar studies before, makes it possible to obtain information on the subject's method of coping with stress, thus allowing for the initiation of a relevant psychological therapy aiding the prosthetic treatment.

Clinical implications of calcifying nanoparticles in dental diseases: a critical review.

BACKGROUND: Unknown cell-culture contaminants were described by Kajander and Ciftçioglu in 1998. These contaminants were called nanobacteria initially and later calcifying nanoparticles (CNPs). Their exact nature is unclear and controversial. CNPs have unique and unusual characteristics, which preclude placing them into any established evolutionary branch of life. AIM: The aim of this systematic review was to assess published data concerning CNPs since 1998 in general and in relation to dental diseases in particular. MATERIALS AND METHODS: The National Library of Medicine (PubMed) and Society of Photographic Instrumentation Engineers (SPIE) electronic and manual searches were conducted. Nanobacteria and calcifying nanoparticles were used as keywords. The search yielded 135 full-length papers. Further screening of the titles and abstracts that followed the review criteria resulted in 43 papers that met the study aim. CONCLUSION: The review showed that the existence of nanobacteria is still controversial. Some investigators have described a possible involvement of CNPs in pulpal and salivary gland calcifications, as well as the possible therapeutic use of CNPs in the treatment of cracked and/or eroded teeth.

Cytotoxicity of Brazilian plant extracts against oral microorganisms of interest to dentistry.

BACKGROUND: With the emergence of strains resistant to conventional antibiotics, it is important to carry studies using alternative methods to control these microorganisms causing important infections, such as the use of products of plant origin that has demonstrated effective antimicrobial activity besides biocompatibility. Therefore, this study aimed to evaluate the antimicrobial activity of plant extracts of Equisetum arvense L., Glycyrrhiza glabra L., Punica granatum L. and Stryphnodendron barbatimam Mart. against Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mutans, Candida albicans, Candida tropicalis, and Candida glabrata, and to analyze the cytotoxicity of these extracts in cultured murine macrophages (RAW 264.7). METHODS: Antimicrobial activity of plant extracts was evaluated by microdilution method based on Clinical and Laboratory Standards Institute (CLSI), M7-A6 and M27-A2 standards. The cytotoxicity of concentrations that eliminated the microorganisms was evaluated by MTT colorimetric method and by quantification of proinflammatory cytokines (IL-1ß and TNF-α) using ELISA. RESULTS: In determining the minimum microbicidal concentration, E. arvense L., P. granatum L., and S. barbatimam Mart. extracts at a concentration of 50 mg/mL and G. glabra L. extract at a concentration of 100 mg/mL, were effective against all microorganisms tested. Regarding cell viability, values were 48% for E. arvense L., 76% for P. granatum L, 86% for S. barbatimam Mart. and 79% for G. glabra L. at the same concentrations. About cytokine production after stimulation with the most effective concentrations of the extracts, there was a significant increase of IL-1ß in macrophage cultures treated with S. barbatimam Mart. (3.98 pg/mL) and P. granatum L. (7.72 pg/mL) compared to control (2.20 pg/mL) and a significant decrease of TNF-α was observed in cultures treated with G. glabra L. (4.92 pg/mL), S. barbatimam Mart. (0.85 pg/mL), E. arvense L. (0.83 pg/mL), and P. granatum L. (0.00 pg/mL) when compared to control (41.96 pg/mL). CONCLUSIONS: All plant extracts were effective against the microorganisms tested. The G. glabra L. extract exhibited least cytotoxicity and the E. arvense L. extract was the most cytotoxic.

Rabbit dental disease and calcium metabolism--the science behind divided opinions.

Dental disease is considered as one of the, if not, the most common disorders seen in pet rabbits. This article provides a review of the scientific literature and an overview of the peculiarities of calcium homeostasis in the rabbit in an attempt to draw together current thinking on the cause of dental disease. A complete understanding of the aetiology and pathophysiology of rabbit dental disease is necessary for the veterinary practitioner to establish a proper therapeutic plan, prognosis and ultimately prevention of this common cause of morbidity and mortality in pet rabbits.

Dentofacial characteristics of patients with rheumatoid arthritis.

OBJECTIVES: The aims of this study are to evaluate the dentofacial morphology of patients with rheumatoid arthritis (RA) and to compare the morphological data with those of healthy age- and sex-matched control subjects. METHODS: Twenty-seven RA patients (mean age, 45.77 ± 8.64 years) and 25 healthy subjects (mean age, 44.80 ± 8.24 years) participated in this prospective study. Clinical and functional evaluations of the RA patients were assessed. The erythrocyte sedimentation rate, C-reactive protein level, rheumatoid factor level, and anti-citrullinated peptide antibodies (ACPA) titers of RA patients were determined, and DAS28 scores were calculated. Linear and angular measurements were performed on cephalometric tracings and condylar erosion was evaluated on lateral panoramic radiographs. Statistical comparison of the two groups was performed with an independent samples t test. Pearson correlation analysis was used to assess the relationship between the clinical and laboratory parameters. RESULTS: Based on DAS28 scores, no patient with RA was in the remission period, 3 patients had low, 23 had medium, and 1 had high disease activity. Sixteen (59.26 %) patients with RA had positive ACPA titers. Lateral cephalometric radiographs revealed statistically significant difference between the two groups for the measurement of U1-NA (millimeter; p = 0.047), U1-NA (degrees; p = 0.031), L1-NB (degrees; p = 0.030), IMPA (L1-MP; p = 0.001), interincisal angle (U1-L1; degrees; p = 0.022) and midface length (Co-A; millimeter; p = 0.033). A significant positive linear correlation was found between disease duration time and DAS28 scores (r = 0.066, p = 0.040). CONCLUSIONS: Dentoalveolar effects of RA on dentofacial morphology are more significant than the skeletal effects. Future studies with larger sample sizes are required to evaluate the exact effects of RA on dentofacial morphology. CLINICAL RELEVANCE: Clinicians should consider the fact that RA-associated dentoalveolar changes can be observed and may affect the orthodontic treatment process.