Reliability, reproducibility and validity of the conventional buccolingual and mesiodistal measurements on 3D dental digital models obtained from intra-oral 3D scanner Publication date: January 2020 Source: Archives of Oral Biology, Volume 109 Author(s): C. Soto-Álvarez, G.M. Fonseca, J. Viciano, I. Alemán, J. Rojas-Torres, M.H. Zúñiga, S. López-Lázaro Abstract Objective The aims of this study were to assess the reliability, reproducibility and validity of mesiodistal and buccolingual measurements comparing these measurements collected using an electronic hand-held digital calliper, on dry dentitions and on dental casts, with measurements obtained from 3D digital models created using a portable intra-oral scanner. Design The mesiodistal and buccolingual diameter of the crown of 1304 teeth were measured on dry dentitions and on dental casts, and secondly on 3D digital models created using an intra-oral 3D scanner. Reliability, reproducibility and validity were evaluated using the intraclass correlation coefficient (ICC) and the Bland-Altman graphic method. Results The results of the intraclass correlation coefficient expressed an excellent degree of agreement in the intra- and inter-observer error analysis, as well as in the comparison of the mesiodistal and buccolingual dimensions taken with the calliper and those taken in digital 3D models. The results of the Bland-Altman method showed that the greatest differences were found in the mesiodistal diameter of the molars and in the buccolingual diameter of the upper premolars. Conclusions Mesiodistal and buccolingual measurements obtained from digital 3D models are suitable for recording dentitions for forensic purposes.

Post-mitotic odontoblasts in health, disease, and regeneration Publication date: January 2020 Source: Archives of Oral Biology, Volume 109 Author(s): S. Rajan, A. Ljunggren, D.J. Manton, A.E Björkner, M. McCullough Abstract Objective Description of the odontoblast lifecycle, an overview of the known complex molecular interactions that occur when the health of the dental pulp is challenged and the current and future management strategies on vital and non-vital teeth. Methods A literature search of the electronic databases included MEDLINE (1966-April 2019), CINAHL (1982-April 2019), EMBASE and EMBASE Classic (1947-April 2019), and hand searches of references retrieved were undertaken using the following MESH terms ‘odontoblast*’, ‘inflammation’, ‘dental pulp*’, ‘wound healing’ and ‘regenerative medicine’. Results Odontoblasts have a sensory and mechano-transduction role so as to detect external stimuli that challenge the dental pulp. On detection, odontoblasts stimulate the innate immunity by activating defence mechanisms key in the healing and repair mechanisms of the tooth. A better understanding of the role of odontoblasts within the dental pulp complex will allow an opportunity for biological management to remove the cause of the insult to the dental pulp, modulate the inflammatory process, and promote the healing and repair capabilities of the tooth. Current strategies include use of conventional dental pulp medicaments while newer methods include bioactive molecules, epigenetic modifications and tissue engineering. Conclusion Regenerative medicine methods are in their infancy and experimental stages at best. This review highlights the future direction of dental caries management and consequently research.

A study of chewing muscles: Age-related changes in type I collagen and matrix metalloproteinase-2 expression Publication date: January 2020 Source: Archives of Oral Biology, Volume 109 Author(s): Mustafa Cicek, Mehmet Kemal Tumer, Velid Unsal Abstract Objective In this study, the aim was to investigate the biochemical, physiological and histological changes that occur in masticatory muscles of the masticatory system with aging. Design In this study, 14 BALB/c mice were used. Animals were divided into two equal groups of seven. Group I was organized as the group of young animals (n = 7) and Group II as the group of adult animals (n = 7). After routine histological follow-up was performed, the tissues were embedded in paraffin. 4–5 μm thick cross-sections were taken from paraffin-embedded tissues and they were stained with Haemotoxylin and Eosin Type I collagen and Matrix metalloproteinase-2 (MMP-2) immunohistochemically. Results It was observed that there was a decrease and shrinking in blood vessels due to aging. In young mice, Type I collagen and MMP-2 immunoreactivity in the masseter muscle tissue showed low staining, while Type I collagen and MMP-2 immunoreactivity in the temporal muscle tissue showed moderate staining. Type I collagen and MMP-2 immunoreactivity were significantly higher in the masseter and temporal muscles of elderly mice (p = 0.001). In the H-score evaluation, MMP-2 immune reactivity was significantly lower in young mice than in older mice (p = 0.001). Conclusion It was determined that severe pain complications and functional losses are likely to occur with the increase of degeneration due to aging of masticator muscles.

Injury responses of Sprague-Dawley rat jaw muscles to an experimental unilateral anterior crossbite prosthesis Publication date: January 2020 Source: Archives of Oral Biology, Volume 109 Author(s): Hong-Yun Zhang, Hong-Xu Yang, Qian Liu, Mian-Jiao Xie, Jing Zhang, Xin Liu, Xiao-Dong Liu, Shi-Bin Yu, Lei Lu, Mian Zhang, Mei-Qing Wang Abstract Objective Dental occlusion are frequently changed in clinic. Molecular responses in jaw muscles to aberrant dental occlusion are changes are attractive, yet remain are obscure. Design Unilateral anterior crossbite (UAC) prostheses were applied to Sprague-Dawley rats and then ceased after two weeks to detect the reactions of the masseter, a representative jaw elevator, and the lateral pterygoid muscle (LPM), a representative jaw depressor. Results Two weeks of UAC elicited mild injury of the two muscles. Myogenesis and protective reactions were detected as increases in αB-crystallin expression in the masseter after 3 days and in the LPM after 2 weeks, and increases in desmin expression in both muscles after 2 weeks. A switch in fibre types from IIb to IIx occurred in the LPM but not in the masseter. Inflammatory responses, shown by the infiltration of inflammatory cells and increases in TNF-α mRNA expression, and fibrosis responses, shown by increased mRNA expression of Type I and III collagens, appeared very mild in the two muscles. These responses were partially recovered by the cessation of UAC. During the whole process, no obvious changes were observed in mitochondrial function, as indicated by the levels of proliferator-activated receptor γ coactivator 1α, mitofusin-2 and voltage-dependent anion channel. Conclusions UAC causes injury and very limited inflammatory and fibrosis adaption in the masseter and LPM. Both muscles respond with myogenesis and protective activity. The LPM responds also with muscle fibre isoform alternations. These alterations were partially recovered by the cessation of dental stimulation at an early stage.

Anti-acidogenic, anti-biofilm and slow release properties of Dodonaea viscosa var. angustifolia flavone stabilized polymeric nanoparticles Publication date: January 2020 Source: Archives of Oral Biology, Volume 109 Author(s): Mpho Sebelemetja, Sharon Moeno, Mrudula Patel Abstract Objective Dental caries is caused by plaque associated oral bacteria including a pioneer species Streptococcus mutans. It has ability to form biofilm and produce acids in the oral cavity. Many oral hygiene products containing plant derived compounds have been investigated for their anti-S. mutans activity. Dodonaea viscosa var. angustifolia (DVA), has been found to have this property. However, beneficial concentrations are difficult to maintain in the oral cavity due to continual saliva flow which can be overcome using nanotechnology. The aim of this study was to investigate the anti-acidogenic, anti-biofilm and slow release properties of DVA derived flavone stabilized polymeric nanoparticles. Methods Crude extract prepared from DVA leaves was fractionated to produce subfractions and the beneficial subfraction (F5.1) was obtained. Polymeric nanoparticles (PLGA-PEG) were prepared, stabilized with the DVA subfraction (F5.1/NPs) and characterized. Anti-S. mutans, anti-acidogenic and antibiofilm properties were determined. The subfraction release profile (substantivity) and cytotoxicity was determined. Results were analyzed using the Wilcoxon sum test (Mann-Whitney). Results F5.1/NPs showed anti-S. mutans property (MIC 1.56 mg/ml). Subinhibitory concentrations of these nanoparticles significantly reduced the acid production in S. mutans (p < 0.01) and also reduced the biofilm formation by 92%. The retention and slow release of the beneficial compound was detected up to 12 h, reaching 0.1 mg/ml concentration at pH 7.4 after 4 h and at pH 5.5 after 5 h. IC50 of F5.1/NPs was 62.5 µg/ml. Conclusion the DVA flavone containing nanoparticles showed anticariogenic activity with improved substantivity. Therefore, they have potential for use to control dental caries. Graphical abstract

Rutin protects human periodontal ligament stem cells from TNF-α induced damage to osteogenic differentiation through suppressing mTOR signaling pathway in inflammatory environment Publication date: January 2020 Source: Archives of Oral Biology, Volume 109 Author(s): Bin Zhao, Wenjing Zhang, Yixuan Xiong, Yunpeng Zhang, Linglu Jia, Xin Xu Abstract Objectives To investigate whether rutin could protect human periodontal ligament stem cells (hPDLSCs) from TNF-α induced damage to osteogenic differentiation in inflammatory environment and detect the underlying mechanism. Materials and methods hPDLSCs were identified by flow cytometery. TNF-α was used to stimulate hPDLSCs to establish an inflammation model in vitro. Alkaline phosphatase (ALP) staining, ALP activity test, and Alizarin Red staining were used to detect the changes of osteogenic differentiation ability. The mRNA and protein levels of osteogenic genes were evaluated by RT-PCR and Western Blot. The expression of mTOR was also detected by Western Blot. Results hPDLSCs were positive to MSCs specific surface markers. The inflammatory environment in vitro could be established by stimulating hPDLSCs with TNF-α (20 ng/mL). TNF-α (20 ng/mL) could decrease the ALP activity and mineralization ability of hPDLSCs and down-regulate the expression of osteogenic genes in inflammatory environment. Moreover, rutin could affect TNF-α (20 ng/mL) induced damage to osteogenic differentiation of hPDLSCs in a dose-dependent manner, 10 μmol/L rutin could significantly reverse the damage caused by TNF-α. In addition, rutin inhibited TNF-α-activated mTOR signal transduction by inhibiting the phosphorylation of mTOR, similar to the effects of rapamycin(a specific mTOR inhibitor). Conclusions Rutin could protect hPDLSCs from TNF-α induced damage to osteogenic differentiation in inflammatory environment, and rutin is expected to become a new candidate drug for the treatment of bone defect of periodontitis.

Proliferation and odontogenic differentiation of human umbilical cord mesenchymal stem cells and human dental pulp cells co-cultured in hydrogel Publication date: January 2020 Source: Archives of Oral Biology, Volume 109 Author(s): Chunyang Huang, Lirong Bao, Tian Lin, Yanling Lu, Yu Wu Abstract Objective The aim of this study was to evaluate the proliferation and odontogenic differentiation of human dental pulp cells (hDPCs) and human umbilical cord mesenchymal stem cells (hUCMSCs) in three-dimensional co-culture system which was established with the help of bone morphogenetic protein-2 (BMP-2) and hydrogel. Methods hDPCs and hUCMSCs were cultured in different concentrations of hydrogel to explore the more suitable concentrations for subsequent experiments. hUCMSCs and hDPCs induced by BMP-2 were co-cultured in the hydrogel. MTT assay was used to measure the cell viability. The differentiation into odontoblast-like cells were measured by the mRNA expression of dentin salivary phosphoprotein (DSPP), dentin matrix protein-1 (DMP-1), alkaline phosphatase and osteocalcin. Alizarin red staining was performed for the formation of mineralized nodules. Results hUCMSCs and hDPCs could grow and proliferate in hydrogel scaffold. The growth rate of cells in lower concentrations hydrogels were higher than that of high concentrations hydrogels (P < 0.05). The study showed that 0.25% hydrogel scaffold was more suitable for subsequent experiments than other groups. Compared with hUCMSCs-monoculture and hDPCs-monoculture, the co-culture groups exhibited more proliferative potential, alkaline phosphatase activity and mineralization nodule formation (P < 0.05). The mRNA expression in co-culture groups were higher than that of hUCMSCs-monoculture, closed to or even higher than that of hDPCs-monoculture. Conclusion 0.25% hydrogel was the suitable concentration in co-culture system for subsequent experiments. The co-culture groups had stronger abilities of odontoblastic differentiation and mineralization than cells-monoculture groups, indicated that the co-culture conditions could regulate cell proliferation and differentiation within a certain range. Graphical abstract

Calcium promotes differentiation in ameloblast-like LS8 cells by downregulation of phosphatidylinositol 3 kinase /protein kinase B pathway Publication date: January 2020 Source: Archives of Oral Biology, Volume 109 Author(s): Jianghong Gao, Zhen Gao, Fan Dang, Xinmei Li, Hao liu, Xiaojing Liu, Meili Gao, Jianping Ruan Abstract Objectives To investigate the effect and mechanism of calcium on LS8 cell differentiation, especially on phosphatidylinositol 3 kinase (PI3K) /protein kinase B(AKT) pathway. Materials and methods Ameloblast-like LS8 cell line was used and additional 0–3.5 mmol/L calcium chloride was treated for 24 h, 48 h. Cell viability and morphological changes, cell cycle and associated regulatory proteins were analyzed. Results No significant effects on morphological changes were observed. Decreased cell viability and increased S phase cells were accompanied by the significant decrease of cyclin A and cyclin B proteins, and significant increase of cyclin D protein in LS8 cells. Additionally, kallikrein-4 and amelotin expressions were significantly increased. Finally, the levels of PI3K, AKT, p-AKT and forkhead box O3 (FOXO3) significantly downregulated after calcium treatment in LS8 cells. Conclusions Calcium inhibit proliferation and promotes differentiation in LS8 cells, this is closely related to the downregulation of PI3K/AKT signal in LS8 cells.

Cytotoxicity and antimicrobial effects of citronella oil (Cymbopogon nardus) and commercial mouthwashes on S. aureus and C. albicans biofilms in prosthetic materials Publication date: January 2020 Source: Archives of Oral Biology, Volume 109 Author(s): Bruno Guandalini Cunha, Cristiane Duque, Karina Sampaio Caiaffa, Loiane Massunari, Isabela Araguê Catanoze, Daniela Micheline dos Santos, Sandra Helena Penha de Oliveira, Aimée Maria Guiotti Abstract Although the effectiveness of some mouthwashes has been proven, phytotherapy is still a field to be explored as an alternative to commercial products. Objective: To evaluate, in vitro, the cytotoxicity and efficacy of two solutions based on citronella oil (CN), on S. aureus and C. albicans biofilms (in formation–adhesion phase and 24 h-biofilm formation) on acrylic resin and nickel-chromium alloy samples (one trademark of each material), compared to two alcohol-free commercial mouthwashes. Material and Methods: Two solutions containing CN at concentrations of 5x and 10x the minimum bactericidal/fungicidal concentration (MBC/MFC) were prepared by microdilution. After contamination of the samples surfaces with these microorganisms, the mouthwashes (CN - 5x and 10x; CHX - 0,12% alcohol-free chlorhexidine and LT - alcohol-free essential oils) were evaluated. Mouthwash simulation was performed for 1 min at two moments, the first simulation after 4 h of microbial adhesion and 24 h-biofilm formation, and the second simulation, 6 h after the first simulation. For biofilm quantification, the number of cultured cells was evaluated by CFUs. The cytotoxicity assay was performed on HaCat epithelial cells and quantified by the MTT method. Results: Tested solutions completely inhibited the growth of both microorganisms in the adhesion phase. All solutions showed inhibitory activity against 24 h-biofilm formation. However, CN led to greater microbial reduction, regardless of the surface of the sample. All solutions demonstrated a toxic effect. However, after serial dilution, CN presented the lowest cytotoxic effect. Conclusion: Citronella had a lower cytotoxic effect and a higher action compared to commercial solutions.

Comparative study of xeno-free induction protocols for neural differentiation of human dental pulp stem cells in vitro Publication date: January 2020 Source: Archives of Oral Biology, Volume 109 Author(s): Thulasi Thiruvallur Madanagopal, Alfredo Franco-Obregón, Vinicius Rosa Abstract Objective To compare three different xeno-free protocols for neural differentiation of human dental pulp stem cells (DPSC). Methods DPSC were treated with three different media to induce neural differentiation namely N1 (DMEM for 5 days), N2 (PSC neural induction media for 7 days) and N3 (neural media with B27 supplement, 40 ng/ml bFGF and 20 ng/ml EGF for 21 days). Cell proliferation (MTS assay), morphology, gene (qPCR for NESTIN, VIMENTIN, TUB-3, ENO2, NF-M and NF-H) and protein expression (flow cytometry) of neurogenic markers were assessed at different time points and compared to untreated cells (DMEM supplemented with 10% FBS). Statistical analysis was performed with global significance level of 5%. Results N1 and N2 formulations increased the genetic expression of two out of six genes TUB-3, NF-M and TUB-3, NF-H, respectively, whereas N3 elevated the expression of all genes by the late stage. N3 also stimulated protein expression for NESTIN, TUB-3 and NF-H. Cells treated with both N2 and N3 presented neuron-like morphology, decreased proliferation and expression of stemness genes at protocol end point. Conclusion N3 was the most effective formulation in promoting a neurogenic shift in gene and protein expression. Cells provided with the N3 formulation exhibited neuron-like morphology, elaborating axonal-like projections concomitant with cell cycle withdrawal and reduced expression of stemness genes indicating greater commitment to a neurogenic lineage.