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"Root development of permanent teeth is disturbed in survivors of childhood cancer. Cyclophosphamide (CY) is a cytostatic drug commonly used for chemotherapy in children with cancer. This study aimed to evaluate the effects of CY on the development of molar teeth until the completion of occlusion in young mice, focusing on Hertwig’s epithelial root sheath (HERS). We treated thirty-two 12-day-old ICR mice with CY (100 mg/kg; 100-CY group), and 36 control mice with saline. At 12, 14, 16, 20, 24, 27, 39, 60, and 76 days of age, the mandibular molars were removed. Soft X-ray radiographs were obtained in lateral projection. The root/crown length (R/C) ratio of the first molar was calculated. Serial sagittal sections were prepared and histomorphological hematoxylin and eosin (HE) staining and immunohistochemical (cytokeratin) studies were performed. The R/C ratio of the 100-CY group (0.78) was smaller than that of the control group (1.23) at 76 days (p < 0.05, t test). While all roots developed further after injection, microscopic examination showed that the roots of the first molars that developed in the 100-CY group were shorter than those in the control group. In addition, experimental mice showed apical closure of the roots. By 20 days after injection, the HERS had disappeared from the root surface in the 100-CY group. In conclusion, this study indicates that CY can induce a defect in HERS and cause early loss of HERS. Disruption of the epithelial sheath inhibits normal root formation, and it could cause irreversible short-root development."

"IntroductionOlmsted syndrome is a rare palmoplantar keratodermal disease that has not previously been reported to have an association with periodontal disease. The aim of this study is to report and document a case of Olmsted syndrome with evidence of severe periodontal disease.Case reportA 38-year old Saudi male patient presented to the dental clinic diagnosed previously with Olmsted syndrome. Clinical and radiographic examinations were done and provided evidence of the typical clinical findings in Olmsted syndrome and evidence of severe periodontal disease. The patient had severe generalized hyperkeratotic lesions on the palms, soles, and perioral skin as well as hyperkeratosis of oral mucosa at multiple sites.ConclusionThis case report documents the first reported case of Olmsted syndrome to be associated with severe periodontal disease. The altered differentiation of oral mucosa linked to Olmsted syndrome may contribute to the periodontal disease. Patients diagnosed with this syndrome should receive a comprehensive oral examination to determine whether periodontal destruction is a significant component of their disease or not."

"This study investigated the long-term clinical outcome of root canal treatment. 240 root-treated teeth (n = 61 patients) were initially classified on the basis of radiographic presence/absence of initial apical periodonti- tis (IAP) and clinical data. The final outcome measure was the periapical healing (healed/disease). The outcome at 6–9 months was correlated with the outcome at 10 years following treatment. Prognostic factors for the periapical healing were assessed. Extraction data were recorded. Univariate and multivariate logistic regression analysis was used to identify risk indicators for apical periodontitis (AP) development. Chi-square analysis was performed to eval- uate a possible relationship between the 6–9 months out- come and the final outcome related to IAP. Mean observation time was 14 ± 3.7 years. Survival rate was 84.6 % and healing rate was 79 % (10–19 years). Predic- tors of outcome (p \ .05) were considered statistically significant. Multivariate logistic regression analysis showed that initial pulpal and periapical status and the quality of root canal filling as assessed two-dimensionally were independent predictors of outcome. The 6–9 months evaluation appears to be an indicator for the final outcome of primary root canal treatment both in the presence and in the absence of IAP. An initial radiolucency associated with an unsatisfactory quality and extent of root canal filling significantly diminishes the possibility of achieving long- term radiographic success. For those with uncertain healing at 6–9 months (91 %), clinicians should consider the high healing rate when estimating the prognosis and adjust the decision making accordingly."

"Our understanding of the evolution of the dentition has been transformed by advances in the developmental biology, genetics, and functional morphology of teeth, as well as the methods available for studying tooth form and function. The hierarchical complexity of dental developmental genetics combined with dynamic effects of cells and tissues during development allow for substantial, rapid, and potentially non-linear evolutionary changes. Studies of selection on tooth function in the wild and evolutionary functional comparisons both suggest that tooth function and adaptation to diets are the most important factors guiding the evolution of teeth, yet selection against random changes that produce malocclusions (selectional drift) may be an equally important factor in groups with tribosphenic dentitions. These advances are critically reviewed here."

"Over the past decade, platelet-rich plasma (PRP), a platelet-concentrated plasma fraction, has been widely investigated and applied to regenerative medicine. The clinical utility of PRP is supported by evidence that PRP contains high concentrations of platelet-related growth factors and normal concentrations of plasma-derived fibrinogen, both of which contribute synergistically to the regenerative process. Additionally, its superior cost-efficacy versus conventional therapies is attractive to many clinicians. However, current disadvantages of PRP include a relatively complicated preparation procedure and variable operator-dependent efficacy. An additional disadvantage is the use of bovine thrombin, an animal-derived biological, as a coagulant. Many of these disadvantages are overcome by recent advances in preparation procedures and devices; for example, Joseph Choukroun simplified the platelet-rich fibrin preparation procedure and improved handling efficiency without the aid of animal-derived factors. With advancements in cell processing technology, there has been a general shift in cell therapy from autologous to allogeneic treatment; however, autologous PRP therapy will not easily be replaced by allogeneic treatment in the near future. Therefore, to provide more predictable regenerative therapy outcomes using autologous PRP, further investigations should address developing a standardized procedure for PRP preparation to augment its efficacy and potency, independent of donor variability. We would then propose that operators and clinicians prepare PRP according to the standardized protocol and to carefully evaluate the clinical scenario (i.e., recipient factors comprising skeletal defects) to determine which factor(s) should be added to PRP preparations. This careful approach will lead to improved clinical outcomes for patients."

"Fibroblast growth factors (FGFs) regulate the proliferation and differentiation of various cells via their respective receptors (FGFRs). During the early stages of tooth development in fetal mice, FGFs and FGFRs have been shown to be expressed in dental epithelia and mesenchymal cells at the initial stages of odontogenesis and to regulate cell proliferation and differentiation. However, little is known about the expression patterns of FGFs in the advanced stages of tooth development. In the present study, we focused on FGF18 expression in the rat mandibular first molar (M1) during the postnatal crown and root formation stages. FGF18 signals by RT-PCR using cDNAs from M1 were very weak at postnatal day 5 and were significantly up-regulated at days 7, 9 and 15. Transcripts were undetectable by in situ hybridization (ISH) but could be detected by in situ RT-PCR in the differentiated odontoblasts and cells of the sub-odontoblastic layer in both crown and root portions of M1 at day 15. The transcripts of FGFR2c and FGFR3, possible candidate receptors of FGF18, were detected by RT-PCR and ISH in differentiated odontoblasts throughout postnatal development. These results suggest the continual involvement of FGF18 signaling in the regulation of odontoblasts during root formation where it may contribute to dentin matrix formation and/or mineralization."

"The dental pulp tissue is encased in hard tissue and surrounded by hard tissue-forming cells, but remains in a non-mineralized state itself, suggesting the presence of regulatory mechanisms precluding pulp mineralization. This study aimed to reveal the regulatory function of periostin (Postn), which is essential for osteoblast differ- entiation, for odontoblast differentiation/mineralization. We evaluated the effects of Postn overexpression and RNAi-mediated suppression in mouse dental papilla cells (MDPs) on the expression of odontoblastic markers and Notch signaling molecules, and on the formation of mineralized nodules. Localization of Postn in the dental pulp tissue of normal and cavity-prepared molars was observed immunohistologically. Enforced overexpression of Postn in MDPs induced down-regulation of odonto- blastic markers and in vitro mineralization. Conversely, silencing of Postn mRNA in MDPs induced up-regulation of odontoblastic markers and ALP activity. Up- and down- regulation of Postn caused increased and decreased expression, respectively, of Notch signaling molecules. Postn expression was minimal in normal dental pulp, but was rapidly and globally increased in the whole pulp tissue of molar teeth at 1 day after cavity preparation, decreasing thereafter. These results indicate that Postn may be a negative regulator of odontoblast differentiation/mineralization, and that may exert its actions via Notch signals."

"This study evaluated the effect of the combi- nation of two dimethacrylate-based monomers [bisphenol A diglycidyl dimethacrylate (BisGMA) or bisphenol A ethoxylated dimethacrylate (BisEMA)] with diluents either derived from ethylene glycol dimethacrylate (ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol di- methacrylate) or 1,10-decanediol dimethacrylate (D3MA) on network characteristics and mechanical properties of neat resin and composite materials. The degree of con- version, maximum rate of polymerization and water sorp- tion/solubility of unfilled resins and the flexural strength and microhardness of composites (after 24 h storage in water and 3 months storage in a 75 vol% ethanol aqueous solution) were evaluated. Data were analyzed with two- way ANOVA and Tukey’s test (a = 0.05). The higher conversion and lower water sorption presented by BisEMA co-polymers resulted in greater resistance to degradation in ethanol compared with BisGMA-based materials. In gen- eral, conversion and mechanical properties were optimized with the use of long-chain dimethacrylate derivatives of ethylene glycol. D3MA rendered more hydrophobic mate- rials, but with relatively low conversion and mechanical properties."

"Based on scarce evidence, fatty acids have been described as anticariogenic. The aim was to evaluate the effect of different types of fatty acids on enamel demin- eralization and on the cariogenic properties of Strepto- coccus mutans biofilms on a biofilm/caries model. Mature biofilms of S. mutans UA159 growing on bovine enamel slabs were exposed to 10 % sucrose for 5 min, 3 times per day followed by exposure to a panel of free fatty acids, including monounsaturated (oleic), polyunsaturated (lino- leic) and saturated (stearic) fatty acids, in concentrations of 0.1, 1 and 10 mM for five additional minutes. Enamel demineralization was determined before and after the experiments by microhardness. Slabs were retrieved to analyze biofilm biomass, viable bacterial counts and polysaccharide production. Biofilms exposed to sucrose, followed by oleic and linoleic acids, showed less demin- eralization than sucrose alone (p \ 0.05). Biomass, S. mutans colonies and insoluble extracellular polysaccharide production were reduced from the biofilms treated with oleic and linoleic fatty acids (p \ 0.05). No differences with the positive control were observed with the saturated stearic acid. Poly and monounsaturated fatty acids presented to S. mutans biofilms after a cariogenic challenge appear to reduce demineralization on enamel and to interfere with cariogenicity of S. mutans biofilms"

"The enamel defects (EDs) may present with a variety of clinical manifestations with increasing severity from the sole appearance of pale discoloration to remarkable structural alterations. EDs are responsible for higher caries receptivity. In vivo reflectance confocal microscopy (RCM) allows to image in vivo at microscopic resolution of the dental surface, thus avoiding the tooth extraction and the sample preparation because of its ability to optically scan living tissues along their depth. Aim of this study is the in vivo assessment at microscopic resolution of dental surfaces affected by EDs without resorting to invasive methods such as teeth extractions, to define histological findings occurring in chromatic and/or structural EDs. For the purpose, 15 children, referring at the Dental Clinic of the Second University of Naples, affected by several degrees of EDs, were enrolled and underwent in vivo RCM imaging to microscopically define the ED confocal features using a commercially available hand-held reflectance confocal microscope with neither injuries nor discomfort. Totally, 29 teeth were imaged. Results demonstrated images good in quality and the capability to detect EDs such as unevenness, grooves, and lack of mineralization according to their clinical degree of disarray. The present in vivo microscopic study on EDs allowed to highlight structural changes in dental enamel at microscopic resolution in real-time and in a non-invasive way, with no need for extraction or processing the samples. Further experiments could define the responsiveness to remineralizing procedures as therapeutic treatments."