Osteoclast formation from mouse bone marrow cells on micro/nano-scale patterned surfaces

ObjectivesOsteoclasts can sense the surface topography of materials. However, it is difficult to identify the structural factors that affect osteoclast formation and its function. Furthermore, we hypothesized that the type of osteoclast precursor cells also affects osteoclastogenesis in the materials. In this study, we investigated the effects of defined micro/nanoscale patterns on osteoclastogenesis from bone marrow cells (BMCs).MethodsVarious cyclo-olefin polymer (COP) patterns were prepared using nanoimprinting. The effects of shape, size, and height of the patterns, and the wettability of the patterned surfaces on osteoclastogenesis from BMCs were evaluated in vitro.ResultsOsteoclast formation was promoted on pillars (diameter, 1 μm or 500 nm; height, 500 nm). Notably, osteoclastogenesis from BMCs was better promoted on hydrophobic pillars than on hydrophilic pillars. In contrast, decreased osteoclast formation was observed on the nanopillars (diameter, 100 nm; height, 200 nm).ConclusionsWe demonstrated the promotion of osteoclast formation from BMCs on hydrophobic pillars with diameters of 1 μm and 500 nm. Some cellular behaviors in the patterns were dependent on the type of osteoclast precursor cells. The designed patterns are useful for designing the surface of dental implants or bone replacement materials with a controllable balance between osteoblast and osteoclast activities.     

Development of a method for the identification of receptor activator of nuclear factor-κB+ populations in vivo

ObjectivesOsteoclasts are induced by macrophage colony-stimulating factor-1 (CSF-1) and receptor activator of nuclear factor-κB (RANK) ligand (RANKL). Monocyte/macrophage lineages are thought to be osteoclast precursors; however, such cells have not been fully characterized owing to a lack of tools for their identification. Osteoclast precursors express colony-stimulating factor-1 receptor (CSF-1R) and RANK. However, the capacity of conventional methods using anti-RANK antibodies to detect RANK⁺ cells by flow cytometry is insufficient. Here, we developed a high-sensitivity method for detecting RANK⁺ cells using biotinylated recombinant glutathione S-transferase-RANKL (GST-RANKL-biotin).MethodsWe sorted sub-populations of mouse bone marrow (BM) or peripheral blood (PB) cells using GST-RANKL-biotin, anti-CSF1R, and anti-B220 antibodies and induced osteoclastogenesis in vitro.ResultsThe frequency of the RANK⁺ population in BM detected by GST-RANKL-biotin was significantly higher than that detected by anti-RANK antibodies. Although RANK⁺ cells were detected in both the B220⁺ and B220^? populations, the macrophage lineage was present only in B220^?. Unexpectedly, a significantly higher number of osteoclasts was induced in RANK^?CSF-1R⁺ cells than in RANK⁺CSF-1R⁺ cells contained in the B220^? population. In contrast, the PB-derived B220^?RANK⁺CSF-1R⁺ population contained a significantly higher frequency of osteoclast precursors than the B220^?RANK^?CSF-1R⁺ population.ConclusionsThese results suggest that GST-RANKL-biotin is useful for the detection of RANK⁺ cells and that RANK and CSF-1R may be helpful indicators of osteoclast precursors in PB.     

The use of propolis in dentistry,oral health,and medicine: A review

BackgroundPropolis is a resinous product that is collected from plants by bees to cover holes and crevices in their hives. Propolis has potent antibacterial, antiviral, anti-inflammatory, wound healing, and anticancer properties. Propolis has been used therapeutically by humans for centuries, including the treatment of dental caries and mouth infections.HighlightThis review article attempts to analyze the potential use of propolis in general dentistry and oral health management.ConclusionPropolis is potentially useful in dentistry and oral health management based on available in vitro, in vivo, and ex vivo studies, as well as human clinical trials.     

Healing of experimental gingival recession defects treated with amnion allograft: Histologic and histometric analysis in dogs

ObjectivesThis study was conducted to compare the healing response of localized gingival recession defects treated with a coronally advanced flap (CAF) and either an amnion allograft membrane (AM) or a connective tissue graft (CTG).MethodsGingival recession defects were surgically created in six healthy mongrel dogs at the labial root surface of the maxillary canines, bilaterally. Using a split mouth design, the defects were treated with CAF and either AM (CAF/AM) or CTG (CAF/CTG). Three animals for each group were scarified at 1 and 3 months. Segments containing the defects were prepared for histological and histometric analysis.ResultsBoth techniques showed similar clinical findings with adequate root coverage. Histologically, healing was characterized by the formation of new cementum and new connective tissue attachment in the CAF/AM group; in the CAF/CTG group, healing was characterized by junctional epithelium, coronally, and connective tissue fibers parallel to the root surface, apically. Histometrically, the CAF/AM group revealed a substantially shorter epithelial length and a longer, new cementum compared with those of the CAF/CTG group after a healing period of 3 months.ConclusionsWithin the limits of this study, we concluded that the AM allograft could promote periodontal healing in gingival recession defects.     

Adipose-derived mesenchymal stem cells promote salivary duct regeneration via a paracrine effect

ObjectivesThe self-regeneration of exocrine tissues, including salivary glands, is limited and their regeneration mechanism has not yet been fully elucidated. Here we identify the role of adipose-derived mesenchymal stem cells (AMSCs) in salivary gland regeneration.MethodsAMSCs expressing mesenchymal stem cell markers were applied to a submandibular gland injury model and the mechanism of salivary gland repair and regeneration was analyzed.ResultsTransplanted green fluorescent protein (GFP)-labeled AMSCs grew tightly together and promoted ductal regeneration in the regenerative nodule, with slight infiltration of nonspecific immune cells. A comprehensive gene analysis through RNA-sequencing revealed increased expression of bone morphogenetic protein (BMP), transforming growth factor (TGF), and Wnt in AMSC-transplanted regenerative nodules. The factors released from AMSCs scavenge hydrogen peroxidase-induced reactive oxygen species (ROS) through Wnt promoter activity in vitro. Furthermore, AMSC-conditioned medium recovered the growth of the hydrogen peroxidase-damaged primordium of the submandibular gland culture ex vivo.ConclusionsThese results suggest that AMSC-released factors scavenge ROS and maintain salivary gland repair and regeneration via paracrine effects. Thus, AMSCs could be a practical and applicable tool for use in salivary gland regeneration.     

Biochemical and X-ray micro-computed tomographic analyses of critical size bone defects grafted with autogenous bone and mercerized bacterial cellulose membranes salified with alendronate

ObjectivesThis study aimed to evaluate the repair of critical-sized bone defects grafted with autogenous bone and mercerized bacterial cellulose membranes (BCm) salified with alendronate (ALN).MethodsForty-eight male Wistar rats underwent surgery to create a 5 mm-diameter bone defect in the calvarium. The removed bone was particularized, regrafted into the defect, and covered by a BCm according to the group: control group (CG), simply mercerized BCm; group 1 (G1), negatively charged BCm (BCm-CM^-) salified with ALN; and group 2 (G2), positively charged BCm (BCm-DEAE⁺) salified with ALN. Serum samples were collected preoperatively and before euthanasia to analyze osteoprotegerin (OPG), parathyroid hormone (PTH), sclerostin (SOST), and fibroblast growth factor 23 (FGF23) levels. The animals were euthanized after 15 or 60 d. Calvaria were analyzed using quantitative microtomography (μCT).ResultsThere was an increased level of PTH in the CG compared to the G2 group, at day 60 (p = 0.019). When analyzing the same group over time, G1 presented an increased FGF23 level on days 15 and 60 (p < 0.05). CG presented an increase in PTH (p = 0.037) at day 60. The μCT analysis detected increased trabecular separation on day 15 in G2 compared to G1 (p = 0.040).ConclusionsSalification of ionized BCm with ALN had no direct effect on bone repair; however, BCm-CM^- increased the levels of FGF23 over time. BCm-DEAE⁺ decreased PTH levels compared to mercerized BCm. BCm-CM-salified with ALN-induced superior bone quality, with respect to trabecular separation, compared to BCm-DEAE⁺.     

Tooth-level predictors of tooth loss and exposed bone after radiation therapy for head and neck cancer

BackgroundThe objective of this study was to identify tooth-level risk factors for use during preradiation dental care management to predict risk of tooth failure (tooth lost or declared hopeless) and exposed bone after radiation therapy (RT) for head and neck cancer (HNC).MethodsThe authors conducted a prospective observational multicenter cohort study of 572 patients receiving RT for HNC. Participants were examined by calibrated examiners before RT and then every 6 months until 2 years after RT. Analyses considered time to tooth failure and chance of exposed bone at a tooth location.ResultsThe following pre-RT characteristics predicted tooth failure within 2 years after RT: hopeless teeth not extracted pre-RT (hazard ratio [HR], 17.1; P < .0001), untreated caries (HR, 5.0; P < .0001), periodontal pocket 6 mm or greater (HR, 3.4; P = .001) or equaling 5 mm (HR, 2.2; P = .006), recession over 2 mm (HR, 2.8; P = .002), furcation score of 2 (HR, 3.3; P = .003), and any mobility (HR, 2.2; P = .008). The following pre-RT characteristics predicted occurrence of exposed bone at a tooth location: hopeless teeth not extracted before RT (risk ratio [RR], 18.7; P = .0002) and pocket depth 6 mm or greater (RR, 5.4; P = .003) or equaling 5 mm (RR, 4.7; P = .016). Participants with exposed bone at the site of a pre-RT dental extraction averaged 19.6 days between extraction and start of RT compared with 26.2 days for participants without exposed bone (P = .21).ConclusionsIndividual teeth with the risk factors identified in this study should be considered for extraction before RT for HNC, with adequate healing time before start of RT.Practical ImplicationsThe findings of this trial will facilitate evidence-based dental management of the care of patients receiving RT for HNC. This clinical trial was registered at Clinicaltrials.gov. The registration number is NCT02057510.     

A Ser252Trp substitution in mouse FGFR2 results in hyperplasia of embryonic salivary gland parenchyma

ObjectivesMutations in the fibroblast growth factor receptor 2 (FGFR2) gene are responsible for several severe forms of craniosynostotic disorders, such as Apert and Crouzon syndromes. Patients with craniosynostotic disorders caused by a mutation in Fgfr2 present with several clinical symptoms, including hypersalivation. Here we used a transgenic mouse model of Apert syndrome (Fgfr2^+/S252W mice) to evaluate the morphology of the submandibular glands at embryonic day 15.5 (E15.5), the time point reported to mark the start of lumen formation.MethodsFgfr2^+/S252W mice were generated by crossing ACTB-Cre^+/+ and Fgfr2^+/Neo-S252W mice. After measuring body weight, the submandibular glands were collected at E15.5. H&E staining, immunostaining, and RT-qPCR were performed to investigate the development of the submandibular gland.ResultsThe number of ducts and acini in Fgfr2^+/S252W mice was significantly higher than in control littermates; however, lumen formation was not affected. The mRNA expression of Fgf1, Fgfr1, Mmp2, Bmp4, Bmp7, Dusp6, and Etv5 in Fgfr2^+/S252W mice was significantly higher compared to control littermates. Immunoreactivity for FGF3, FGF1, BMP4, and F4/80 was detected in the parenchyma of Fgfr2^+/S252W mice. The area of apoptotic cells stained with TUNEL in Fgfr2^+/S252W mice was significantly larger than that of the control littermates.ConclusionsThese results suggested that increased FGFR1 signaling and apoptosis in the submandibular glands of Fgfr2^+/S252W mice occurred at E15.5, leading to parenchymal hyperplasia. This study demonstrated that a Ser252Trp substitution in mouse FGFR2 resulted in hyperplasia of the submandibular gland parenchyma during development.     

The effect of mouthrinses on severe acute respiratory syndrome coronavirus 2 viral load: A systematic review

BackgroundConsidering that the oral cavity is a major entryway and reservoir for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the aim of the authors was to perform a systematic review of in vivo and in vitro studies to assess the effectiveness of mouthrinses on SARS-CoV-2 viral load.Types of Studies ReviewedThe authors searched PubMed, Web of Science, Scopus, MedRxiv, and bioRxiv databases, including in vitro and in vivo studies assessing the virucidal effect of mouthrinses on SARS-CoV-2 or surrogates. From a total of 1,622 articles retrieved, the authors included 39 in this systematic review.ResultsPovidone-iodine was the most studied mouthrinse (14 in vitro and 9 in vivo studies), frequently showing significant reductions in viral load in in vitro assays. Similarly, cetylpyridinium chloride also showed good results, although it was evaluated in fewer studies. Chlorhexidine gluconate and hydrogen peroxide showed conflicting results on SARS-CoV-2 load reduction in both in vitro and in vivo studies.Practical ImplicationsPovidone-iodine–based mouthrinses appear to be the best option as an oral prerinse in the dental context for SARS-CoV-2 viral load reduction. Although the results of primary studies are relevant, there is a need for more in vivo studies on mouthrinses, in particular, randomized controlled clinical trials, to better understand their effect on SARS-CoV-2 viral load and infection prevention.     

Critical features of periodontal flaps with regard to blood clot stability: A review

BackgroundWound healing is a multifactorial procedure involving different cell types and biological mediators. The principles of wound healing are also applicable to periodontal tissues. The formation and stability of blood clots play a vital role in successful healing of wounds in periodontal tissues. The aim of the present review was to highlight the vital factors of periodontal flaps associated with blood clot stability.HighlightThe data on periodontal regeneration and wound healing have evolved greatly in light of several factors, including space for blood clots and blood clot stabilization. In periodontal osseous defects, the stability of blood clots seems critical to wound healing. If mechanical forces can be managed by wound stabilization, the gingival flap-tooth root interface may show connective tissue repair. However, compromised adhesion is susceptible to mechanical forces and can cause wound breakage and epithelialization.ConclusionThe presence of a thick blood clot may hinder the plasmatic circulation between the recipient bed and graft during the initial stage of healing, which is critical in cases of mucogingival surgery. Root conditioning can also determine the healing consequence by enhancing blood clot adhesion.     

Effect of Myd88 deficiency on gene expression profiling in salivary glands of female non-obese diabetic (NOD) mice

ObjectivesSjögren's syndrome (SS) is a chronic autoimmune disease characterized by inflammatory lesions in the salivary and lacrimal glands, which are caused by distinct lymphocytic infiltrates. Female non-obese diabetic (NOD) mice spontaneously develop inflammatory lesions of the salivary glands with SS-like pathological features. Previous studies have shown that MyD88, a crucial adaptor protein that activates innate immune signaling, affects lymphocytic infiltration, but its detailed role remains unclear. In this study, we investigated the role of MyD88 through gene expression profiling in the early phase of pathogenesis in the salivary glands of female NOD mice.MethodsSubmandibular glands collected from 10-week-old female wild-type and Myd88-deficient NOD mice were used for RNA preparation, followed by microarray analysis. The microarray dataset was analyzed to identify Myd88-dependent differentially expressed genes (DEGs). Data generated were used for GO enrichment, KEGG pathway, STRING database, and INTERFEROME database analyses.ResultsMyd88 deficiency was found to affect 230 DEGs, including SS-associated genes, such as Cxcl9 and Bpifa2. Most of the DEGs were identified as being involved in immunological processes. KEGG pathway analysis indicated that the DEGs were putatively involved in autoimmune diseases, such as systemic lupus erythematosus and rheumatoid arthritis. Furthermore, the DEGs included 149 interferon (IFN)-regulated genes.ConclusionsMyD88 is involved in the expression of specific genes associated with IFN-associated immunopathological processes in the salivary glands of NOD mice. Our findings are important for understanding the role of MyD88-dependent innate immune signaling in SS manifestation.     

Characterization and evaluation of ascorbic acid-induced cell sheet formation in human periodontal ligament stem cells: An in vitro study

ObjectivesPeriodontal ligament-derived stem cells (PDLSCs) are regarded as a viable option for periodontal regeneration using cell sheet technology. The objective of the present in vitro study was to characterize human PDLSCs based on their phenotypic and biological properties and to evaluate the ascorbic acid (AA or vitamin C)-induced cell sheet by analyzing the molecular markers.MethodsPDLSCs were established from premolars, and their morphology, viability, proliferation, phenotypic marker expression, and ability to differentiate into osteocytes and adipocytes were analyzed. PDLSCs were then induced to form cell sheets using 100 μM AA, and gene expression was examined by real-time polymerase chain reaction.ResultsPDLSCs showed fibroblastic morphology with >95% viability. The cells were highly proliferative and positive for surface antigens CD29, CD73, and CD90 but negative for CD34 and CD45. They were capable of differentiating into osteocytes and adipocytes. Induction with 100 μM AA transformed PDLSCs into two-to three-layered cell sheets. There was no significant upregulation in ALP and RUNX2 expression in the AA-induced cell sheet. However, the expression levels of late osteoblast differentiation marker (bone gamma-carboxy glutamate protein); cementogenic markers (cementum attachment protein and CP23), and genes encoding extracellular matrix (ECM) proteins [collagen type 1 alpha 1 and integrin beta 1) were higher in AA-induced cell sheets by PDLSCs.ConclusionsThe stimulating effect of AA on cell sheet formation by PDLSCs was confirmed by the expression of typical markers involved in osteogenesis/cementogenesis and ECM secretion, which makes this procedure a prospective option for periodontal tissue regeneration applications.     

A historical review of the effects of dental radiography on pregnant patients

BackgroundThe safety of dental radiography performed on pregnant patients has been a controversial topic since the 1960s. This review synthesizes and consolidates findings, from 1957 through 2021, of the effects dental ionizing radiation could have on a pregnant patient and in utero birth defects.Types of Studies ReviewedUsing PubMed, the following key words were searched: pregnancy, radiology, radiograph, radiation dose, fetus, x-ray, and dental. Criteria evaluation was done on the basis of availability, completeness, quality, relevance, technicality (that is, dental radiography), topicality (that is, pregnant patients), and usability. These results were then filtered on the basis of quantitative and qualitative data as well as the period (decades within the historical framework). The final selection of relevant literature consisted of various studies including cohort studies, systematic reviews, meta-analyses, case reports, and other narrative reviews.ResultsIf properly performed, the amount of ionizing radiation produced during dental radiographic procedures is so low that it is unlikely to reach the teratogenic threshold. Thus, dental ionizing radiation is unlikely to cause in utero birth defects because it has been detected to have a deterministic (not stochastic) effect. With this information and historical context, this article shows that necessary dental radiography is safe at any stage during pregnancy, as long as proper safety equipment is appropriately used.Conclusions and Practical ImplicationsAs technology advances, more research can further clarify ionizing radiation safety for pregnant patients and its potential effects on in utero birth defects, improving overall oral health care. The dental community must remain educated about current ionizing radiation safety guidelines to make better-informed decisions and successfully provide proper oral health care to pregnant patients.     

Effects of atorvastatin on sevoflurane postconditioning in in vivo rabbit hearts

ObjectivesMyocardial ischemia-reperfusion injury is a phenomenon that promotes myocardial damage when the blood supply returns to the tissue after a period of ischemia. Anesthetic postconditioning involves myocardial protection against myocardial I/R injury. The effects of atorvastatin (ATV) on sevoflurane postconditioning against myocardial ischemia-reperfusion injury have not been thoroughly studied. The present study aimed to investigate if ATV interacts synergistically with sevoflurane postconditioning against myocardial infarction in rabbit hearts in vivo.MethodsTwenty-eight male rabbits underwent 30 min of left anterior descending coronary artery occlusion that was followed by reperfusion for 180 min under ketamine/xylazine (K/X) anesthesia. Rabbits were randomly assigned to four groups that included Group K/X (under K/X anesthesia only), Group POST (sevoflurane exposure at initial reperfusion), Group ATV (ATV 5 mg/kg/day administered before ischemia), and Group ATV + POST (POST intervention with atorvastatin administered once daily for 3 days). At the end of reperfusion, the myocardial infarct size and the area at risk were both measured.ResultsThe mean infarct sizes in the POST, ATV, and ATV + POST groups were significantly smaller compared to those in the K/X group. Furthermore, the mean infarct size in Group ATV + POST was significantly smaller than was that in Group POST and significantly smaller compared to that in Group ATV.ConclusionThe combination of sevoflurane postconditioning and pre-administration of ATV further reduced the myocardial infarction size compared to that observed with sevoflurane postconditioning alone or ATV alone. Our data suggest that sevoflurane postconditioning and ATV may function additively to enhance cardioprotection.     

Impact of hyperglycemia on the rate of implant failure and peri-implant parameters in patients with type 2 diabetes mellitus: Systematic review and meta-analysis

BackgroundThe impact of hyperglycemia on dental implant therapy remains unclear. In this systematic review and meta-analysis, the authors compared the rates of implant failure and peri-implant bleeding on probing (BOP), probing depth (PD), and peri-implant bone loss (PIBL) among patients with type 2 diabetes mellitus and nondiabetic patients. The authors performed subgroup analyses based on glycemic level to evaluate whether patients with higher glycemic levels were more prone to peri-implant inflammation.Type of Studies ReviewedThe authors searched 4 databases for original clinical studies. Studies in which the researchers provided information on the rate of implant failure or peri-implant parameters were included.ResultsNine clinical studies were identified on the basis of the inclusion criteria. No significant differences were found in rates of implant failure (P = .46) and PD (P = .1) between diabetic and nondiabetic patients. Significant differences in BOP (P < .00001) and PIBL (P = .02), favoring nondiabetic patients, were observed. Results of subgroup analyses indicated that the increase in glycemic level did not significantly influence BOP, PD, and PIBL values among diabetic patients.Conclusions and Practical ImplicationsPatients with type 2 diabetes mellitus seem to be able to achieve a rate of implant survival similar to that of healthy patients. Regarding peri-implant parameters, BOP and PIBL were higher in patients with type 2 diabetes mellitus, indicating that hyperglycemia is an important risk factor for peri-implant inflammation. No association was found between peri-implant parameters and glycemic level among patients with type 2 diabetes mellitus, providing oral hygiene was strictly maintained.     

Vitamin C and eggshell membrane facilitate orthodontic tooth movement and induce histological changes in the periodontal tissue

ObjectivesCollagen remodeling of the periodontal tissue is an important mechanism that involves several biologically active substances to accelerate orthodontic tooth movement. It is known that Vitamin C (VC) enhances collagen production and induces tooth movement. Moreover, the eggshell membrane (ESM) is an integral component of various formulations used to promote wound healing. The purpose of our study was to determine the effects of combined treatment with VC and ESM on periodontal tissues during tooth movement.MethodsNine-week-old male osteogenic disorder Shionogi rats were randomized into four groups: control, VC, ESM, and VC + ESM. The control group was given tap water, and the VC, ESM, and VC + ESM groups were orally administered 0.1% VC solution, 1 wt% ESM solution, and a combination of 0.1 wt% VC and 1 wt% ESM solutions, respectively. A force of 25 or 75 g was applied for 10 days to produce orthodontic tooth movement. Distances of tooth movement were measured on days 3, 7, and 10 of treatment. Histological examination of the periodontal ligament was performed to determine the increase in type I and III collagen levels in response to treatment.ResultsDistances of tooth movement were significantly greater in the VC + ESM group than in the control group. The compression area of the alveolar bone showed increased osteoclastic activity and higher levels of bone resorption in the VC + ESM group. Expression levels of type I and III collagen in the tension area of the alveolar bone were higher in the VC + ESM group than in the control group.ConclusionsThis study revealed that the combined administration of VC and ESM accelerated tooth movement by protecting the periodontal tissue during orthodontic treatment. The combined clinical application of VC and ESM could potentially shorten orthodontic treatment time.