Enamel surface loss after erosive and abrasive cycling with different periods of immersion in human saliva Publication date: January 2020 Source: Archives of Oral Biology, Volume 109 Author(s): Raquel Marianna Lopes, Juliana Sant’ Anna da Silva, Samira Helena João-Souza, Vinícius Maximiano, Alana Cristina Machado, Taís Scaramucci, Ana Cecília Correa Aranha Abstract Objective This in vitro study aimed to evaluate different periods of exposure to clarified human saliva for the ability to protect enamel against erosive tooth wear. Methods For this purpose, sixty specimens (4 × 4 × 1.5 mm) were prepared from third human molars. For all groups, the period before abrasion was performed by remineralisation with human saliva (except in G1). The specimens were randomly divided into six groups (n = 10) according to the different remineralisation times of exposure to clarified human saliva: no exposure to saliva (G1) and 30 min (G2), 60 min (G3), 90 min (G4), 120 min (G5), and 240 min (G6) of exposure to human saliva. A 5-day cycling was performed with 5 min of erosion (1% citric acid; pH 2.3), 4x/day. After the first and last erosive episodes, the abrasion challenge was performed with slurry of fluoride toothpaste (1450 ppm F−, as sodium monofluorophosphate) plus human saliva (1:3), with an electric toothbrush (15 s, with a total of 120 s of slurry immersion). Surface loss (SL) was determined using an optical profilometer (n = 10) and for qualitative analysis, environmental scanning electron microscopy (ESEM) was performed (n = 3). The SL data were statistically analysed by one-way analysis of variance (α = 0.05). Results No significant differences were detected among the groups for SL (p > 0.05), and ESEM showed similar aspects of eroded enamel. Conclusions The period of in vitro exposure to clarified human saliva was not able to protect against enamel erosion.

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

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.

Effect of Veillonella parvula on the physiological activity of Streptococcus mutans Publication date: January 2020 Source: Archives of Oral Biology, Volume 109 Author(s): Shiyu Liu, Mengxue Chen, Yuxia Wang, Xuedong Zhou, Xian Peng, Biao Ren, Mingyun Li, Lei Cheng Abstract Objective The aim of this study was to observe the effect of V. parvula on the physiological activity of S. mutans and elucidate the role of V. parvula on dental caries. Design We constructed dual-species biofilms formed by V. parvula and S. mutans, and measured the pH dynamics, biofilm growth, Extracellular Polysaccharide (EPS) synthesis, and expression of S. mutans EPS synthesis-associated genes affected by V. parvula. Results pH dynamics were not altered when V. parvula and S. mutans were co-cultured during a 120 -h test period. However, S. mutans cell number and EPS synthesis in dual-species biofilms were found to be significantly higher than in single-species biofilms. Moreover, expression levels of genes encoding glucosyltransferases (gtfs), gtfB and gtfC specifically, were up-regulated when S. mutans was co-cultured with V. parvula. Conclusions Our findings indicate that V. parvula is not, as previously thought, protective and associated with caries health. On the contrary, V. parvula might participate in caries development through interactions with S. mutans. This study suggests that V. parvula may have an impact on the pathogenesis of dental caries.

Morphological features of tooth development and replacement in the rabbit Oryctolagus cuniculus Publication date: January 2020 Source: Archives of Oral Biology, Volume 109 Author(s): Ludivine Bertonnier-Brouty, Laurent Viriot, Thierry Joly, Cyril Charles Abstract Dental development mechanisms in mammals are highly studied using the mouse as a biological model. However, the mouse has a single, unreplaced, set of teeth. Features of mammalian tooth replacement are thus poorly known. In this paper, we study mammalian tooth development and replacement using the European rabbit, Oryctolagus cuniculus, as a new model. Using 3D-reconstructions associated with histological sections, we obtained the complete description of the histo-morphological chronology of dental development and replacement in rabbit. We also describe in the dentin the presence of holes opening the pulp cavity in newborns. These holes are quickly repaired with a new and fast apposition of dentin from the pre-existing odontoblasts. The detailed dental morphogenesis chronology presented allows us to propose the rabbit Oryctolagus cuniculus as a suitable model to study mammalian tooth replacement.

Comparison of dental caries in Croats from the early medieval period and the 20th century Publication date: January 2020 Source: Archives of Oral Biology, Volume 109 Author(s): Srđan Nedoklan, Antonija Tadin, Zlatka Knezović, Davorka Sutlović Abstract Objective To compare dental caries frequency in the Croatian population exhumed from two archeological periods and compare two methods: International Caries Detection and Assessment System (ICDAS) and DMFT (Decayed-Missing-Filled-Tooth) index. Materials and methods The study included 279 teeth from 69 human remains: Set I of 30 remains and 126 teeth dated from 9th to10th centuries A.D. and Set II of 39 remains and 153 teeth from the recent 20th century. Methods used for caries prevalence were ICDAS and DMFT. Tooth wear was recorded according to the Brabant index. Results ICDAS scoring system showed significantly higher caries frequency in Set I of 64.34% and in Set II 59.47%, compared to DMFT method with 16.52% for Set I and 28.75% for Set II. Dental wear in Set I showed 73.91% and in Set II 73.15%, so no significant difference was observed. Conclusions Depending on the ICDAS or DMFT method used for caries detection, different results have been obtained whereby the ICDAS system has a more precise and advanced approach for caries lesions.

The effect of commercial whitening toothpastes on erosive dentin wear in vitro Publication date: January 2020 Source: Archives of Oral Biology, Volume 109 Author(s): Mariele Vertuan, Beatriz Martines de Souza, Paula Fontana Machado, Victor Mosquim, Ana Carolina Magalhães Abstract Objectives This study evaluated the erosive tooth wear promoted by commercial whitening toothpastes on eroded dentin in vitro. Design Ninety bovine roots were embedded, polished and subjected to the baseline profile analysis. The samples were protected in 2/3 of the dentin surface and were randomly assigned to 6 groups (n = 15/group): Oral-B 3D White; Close-up Diamond Attraction Power White; Sorriso Xtreme White 4D; Colgate Luminous White; Crest and erosion only. All samples were submitted to erosive pH cycles (4 × 90 s in 0.1% citric acid, pH 2.5, per day) and abrasive challenges (2 × 15 s, per day) for 7 days. The samples were subjected to abrasion, using toothbrushing machine, soft toothbrushes and slurries of the tested toothpastes (1.5 N, 1:3 water). Between the challenges, the samples were immersed in artificial saliva. The final profile was overlaid to the baseline profile for the calculation of the erosive dentin wear (μm). The data were subjected to Kruskal-Wallis/Dunn tests (p < 0.05). Results Colgate Luminous White (4.7 μm) and Sorriso Xtreme White 4D (4.0 μm) promoted the highest wear, similarly to Oral-B 3D White (2.3 μm). Oral-B 3D White promoted similar wear compared to Crest (1.1 μm) and Close-up Diamond Attraction Power White (1.2 μm); however, it induced significant higher dentin wear compared to erosion only (1.0 μm). Close-up Diamond Attraction Power White and Crest did not increase the erosive wear compared to erosion only. Conclusion Some whitening toothpastes increase the wear of eroded dentin, which should be considered by the dentist when prescribing them to patient with root exposure.

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.

Tyrosine-hydroxylase, dopamine β-hydroxylase and choline acetyltransferase-like immunoreactive fibres in the human major sublingual gland Publication date: January 2020 Source: Archives of Oral Biology, Volume 109 Author(s): Francesco Loy, Maria Pina Serra, Marianna Boi, Raffaella Isola, Jörgen Ekström, Marina Quartu Abstract Objective To study the innervation of the major sublingual gland by means of immunohistochemistry. Design Bioptic and autoptic specimens of the major sublingual gland of humans were examined for the presence of immunoreactivity to tyrosine hydroxylase and dopamine-β-hydroxylase, on one hand, and choline acetyltransferase, on the other, to indicate adrenergic and cholinergic nerves, respectively. Results Acini and ducts were supplied by both divisions of the autonomic nervous system. Conclusions Mucous and seromucous cells of the human major sublingual glands may respond with secretion not only to parasympathetic activity but also to sympathetic activity. The major sublingual gland is therefore a potential contributor to the mucin secretion recently reported in the literature in response to high sympathetic activity during physical exercise.

The possible role of basic fibroblast growth factor in dental pulp Publication date: January 2020 Source: Archives of Oral Biology, Volume 109 Author(s): Savitri Vaseenon, Nipon Chattipakorn, Siriporn C. Chattipakorn Abstract Fibroblast growth factors (FGFs) are growth factors that play an important role in tooth development, repair, and regeneration. Of the FGF families, basic fibroblast growth factor (bFGF) has been the most frequently investigated in dentistry. Numerous studies have reported advantages of bFGF, while others did not find any additional benefit. This review gives a comprehensive summary of the potential role of bFGF in dental pulp wound healing and regeneration in connection with cell proliferation and differentiation, angiogenesis, and neural differentiation from both in vitro and in vivo studies. Furthermore, the possible underlying mechanisms associated with bFGF in promoting dental pulp wound healing are discussed in this review.