Root coverage of a maxillary lateral incisor with gingival recession, gingival stillman's cleft, bony exostosis, and denture stomatitis: a case report with 3-year follow-up.

BACKGROUND: Coronally advanced flap combined with connective tissue graft is considered as the golden standard of root coverage. Although Miller class I recession is considered to get complete root coverage, there are some uncommon conditions in different cases. This case reported a maxillary lateral incisor with a gingival recession, a stillman's cleft, a bony exostosis and a denture stomatitis. CASE PRESENTATION: A 27-year-old female with a gingival recession, a stillman's cleft and a bony exostosis was treated by coronally advanced flap combined with connective tissue graft technique, and the complete coverage was achieved. Later a denture stomatitis occurred when an acrylic removable partial denture was used, however the gingival margin was not affected. The denture stomatitis disappeared when a new denture with casting palatal plane was produced. In this case of 3-year follow-up, the gingival contour remained stable and the outcome was satisfactory. CONCLUSION: Coronally advanced flap combined with connective tissue graft technique is a classic manner to treat gingival recession especially for a long term stability, even when there is a gingival stillman's cleft, a bony exostosis and a denture stomatitis.

Key Role of the Carboxyl Terminus of Hyaluronan Synthase in Processive Synthesis and Size Control of Hyaluronic Acid Polymers.

The essential pathophysiological roles of hyaluronic acid (HA) strongly depend on HA binding and HA size. Here we deployed the atomic vision of molecular dynamics (MD) simulation to experimentally investigate the influence of C-terminal mutations of Streptococcus equisimilis hyaluronan synthase (SeHAS) on HA product synthesis in Escherichia coli. R413 was vital for HA production, as the removal or mutation of R413 led to inactivation of SeHAS. MD simulations indicated that R406-R413 constituted an HA-binding pattern that stabilized the HA-SeHAS complex. We further increased HA product size via site-directed mutation of the SeHAS C-terminal residues 414-417 based on the hypothesis that higher binding affinity between the SeHAS C-terminus and HA would lead to larger HA size, underlying the important role of the HA-SeHAS interaction in HA size control. W410A and T412A mutations also completely deactivated SeHAS. Moreover, a catalysis-transformation-translocation model was proposed for the HA synthesis and translocation processes.

Frizzled 2 and frizzled 7 function redundantly in convergent extension and closure of the ventricular septum and palate: evidence for a network of interacting genes.

Frizzled (Fz) 2 and Fz7, together with Fz1, form a distinct subfamily within the Frizzled family of Wnt receptors. Using targeted gene deletion, we show that: Fz7(-/-) mice exhibit tail truncation and kinking with 100% penetrance and ventricular septal defects (VSDs) with ~15% penetrance; Fz2(+/-);Fz7(-/-) mice exhibit VSDs with ~50% penetrance and cleft palate with less than 10% penetrance; and Fz2(-/-);Fz7(-/-) mice exhibit convergent extension defects and mid-gestational lethality with 100% penetrance. When Fz2 and/or Fz7 mutations are combined with mutations in Vangl2, Dvl3, Wnt3a, Wnt5a or Wnt11, an increased frequency of VSDs is observed with Dvl3, Wnt3a and Wnt11; an increased frequency of palate closure defects is observed with Vangl2; and early lethality and enhanced tail shortening are observed with Wnt5a. To assess the signaling pathways that underlie these and other Frizzled-mediated genetic interactions, we used transfected mammalian cells to analyze (1) canonical Wnt signaling induced by all pairwise combinations of the ten mouse Frizzleds and the 19 mouse Wnts and (2) localization of each Frizzled at cell-cell junctional complexes formed by mouse Celsr1, a likely indicator of competence for planar cell polarity signaling. These in vitro experiments indicate that Fz2 and Fz7 are competent to signal via the canonical pathway. Taken together, the data suggest that genetic interactions between Fz2, Fz7 and Vangl2, Dvl3 and Wnt genes reflect interactions among different signaling pathways in developmental processes that are highly sensitive to perturbations in Frizzled signaling.

Frizzled 1 and frizzled 2 genes function in palate, ventricular septum and neural tube closure: general implications for tissue fusion processes.

The closure of an open anatomical structure by the directed growth and fusion of two tissue masses is a recurrent theme in mammalian embryology, and this process plays an integral role in the development of the palate, ventricular septum, neural tube, urethra, diaphragm and eye. In mice, targeted mutations of the genes encoding frizzled 1 (Fz1) and frizzled 2 (Fz2) show that these highly homologous integral membrane receptors play an essential and partially redundant role in closure of the palate and ventricular septum, and in the correct positioning of the cardiac outflow tract. When combined with a mutant allele of the planar cell polarity gene Vangl2 (Vangl2(Lp)), Fz1 and/or Fz2 mutations also cause defects in neural tube closure and misorientation of inner ear sensory hair cells. These observations indicate that frizzled signaling is involved in diverse tissue closure processes, defects in which account for some of the most common congenital anomalies in humans.

Periodontal repair for advanced bone loss caused by orthodontic elastic bands: A case report with 7-year follow-up and literature review.

A 16-year-old girl developed severe acute periodontitis involving the maxillary central incisor and lateral incisor caused by elastic bands. Periodontal surgical interventions and orthodontic adjustment achieved good outcomes which were maintained for 7 years. This report demonstrates the criticality of correct diagnosis, early periodontal surgery, and interdisciplinary approach.

Evaluation of the relationship among dental fear, scaling and root planing and periodontal status using periodontitis stages: A retrospective study.

BACKGROUND/PURPOSE: Patients with periodontal disease have higher dental fear levels, which may have negative effects on their clinical outcome during scaling and root planing (SRP). The present study used the new classification of periodontitis and validated questionnaires to assess the relationship among dental fear, SRP pain and periodontal status. MATERIALS AND METHODS: A total of 120 periodontitis patients were enrolled and staging according to the new classification of periodontitis. SRP was performed, and the visual analog scale (VAS) to assess pain was used with every patient after treatment. Questionnaires, including Corah's Dental Anxiety Scale (DAS), Dental Fear Survey (DFS), and short-form Dental Anxiety Inventory (S-DAI) were implemented from the first attendance and subsequent visits after 6 months. The patients were grouped by DAS scores. The statistical analysis was performed using T-test, chi-square, Pearson and Spearman correlative analysis. RESULTS: Compared to pre-SRP treatment, the dental fear level on DFS was decreased in the posttreatment period for all periodontitis stages. There were no statistically significant differences in S-DAI and DAS between pretreatment and posttreatment periods in stage I and II; meanwhile, there were statistically differences in stage III and IV. The correlation among periodontitis stages, VAS and dental fear level was significant. The proportion of high periodontitis stages was increased in high dental fear group. CONCLUSION: SRP can reduce dental fear levels in all periodontitis stages, especially in stage III and IV. Correlations exist among periodontal status, dental fear and SRP pain. High dental fear is associated with poor periodontal status.

Occurrence and sources of microplastics and polycyclic aromatic hydrocarbons in surface sediments of Svalbard, Arctic.

Due to the distinct environment condition and geographic location, Svalbard has been recognized as a potential pollution reservoir in the Arctic. In this study, 8 surface sediment samples were collected from two fjords in Svalbard (Kongsfjorden and Rijpfjorden) in 2017, and they were searched for microplastics and polycyclic aromatic hydrocarbons (PAHs). PAHs were also investigated in 10 soil samples of Ny-Ålesund for local anthropogenic source analysis. The level of microplastics and other anthropogenic particles ranged from not detected (ND) to 4.936 particles/kg dry weight (DW). Fiber was the only shape of the microplastics found and three polymers (polyester, rayon and cellulose) were detected, which suggested that fisheries-related debris and textile materials were possible sources of microplastics and anthropogenic particles. For PAHs, the level of ∑26PAH was 9.2 ng/g to 67.1 ng/g (DW), and were dominated by lnP and BghiP, indicating petroleum combustion source. Further analysis revealed that traffic emissions from cars and diesel combustion from a local power plant were major sources of PAHs in soils of Ny-Alesund, while traffic emissions from ships were the dominate source of PAHs in sediments of Kongsfjorden and Rijpfjorden. A higher level of PAHs was observed in Ny-Alesund, confirming an anthropogenic input, while transport via ocean currents might contribute to the higher abundance of microplastics in Rijpfjorden. Further research and even long-term observation of pollutants are needed to fully understand the pollution status in polar regions.

[Interforaminal regions of 287 Han adults evaluated by cone-beam computed tomography].

PURPOSE: The mandibular anatomical structures including mental foramen, accessory mental foramina, anterior loop were measured and analyzed by cone-beam CT (cone-beam computed tomography, CBCT) , in order to provide some information during surgical procedures in interforaminal regions. METHODS: Two hundred and eighty-seven Chinese Han patients who visited Stomatological Department of Xiangya Hospital were included in this study. Patients were scanned by cone-beam computed tomography, and the information of interforaminal region was collected from the images. SPSS17.0 software package was used for statistical analysis. RESULTS: The mental foramen was usually apical to the second premolar or between the premolars（60.80% and 30.14%, respectively). The accessory mental foramina was observed in 4.88% of the mandibles, most of which were located under the second premolar, superiorly and distally to the mental foramen. The anterior loop was identified in 89.20% of cases with the mean length being (1.99±1.39) mm. The distance from the apex of the second mandibular premolar to the anterior loop or the inferior alveolar nerve was (5.21±2.50) mm. CONCLUSIONS: Accessory mental foramina is present in some mandibles. The anterior loop is highly prevalent in Chinese Han people, and its length is highly variable.

Multiple reuses of Rhodococcus ruber TH3 free cells to produce acrylamide in a membrane dispersion microreactor.

In this work, multiple reuses of Rhodococcus ruber TH3 free cells for the hydration of acrylonitrile to produce acrylamide in a membrane dispersion microreactor were carried out. Through using a centrifuge, the reactions reached 39.9, 39.5, 38.6 and 38.0wt% of the final acrylamide product concentration respectively within 35min in a four cycle reuse of free cells. In contrast, using a stirring tank, free cells could only be used once with the same addition speed of acrylonitrile with a microreactor. Through observing the dissolution behavior of acrylonitrile microdroplets in a free cell solution using a coaxial microfluidic device and microscope, it was found that the acrylonitrile microdroplets with a diameter of 75µm were rarely observed within a length of 2cm channel within 10s, which illustrated that the microreactor can intensify the reaction rate to reduce the inhibition of acrylonitrile and acrylamide.

Immobilization and stabilization of cephalosporin C acylase on aminated support by crosslinking with glutaraldehyde and further modifying with aminated macromolecules.

In this work, cephalosporin C acylase (CA), a heterodimeric enzyme of industrial potential in direct hydrolysis of cephalosporin C (CPC) to 7-aminocephalosporanic acid (7-ACA), was covalently immobilized on the aminated support LX1000-HA (HA) with two different protocols. The stability of CA adsorbed onto the HA support followed by crosslinking with glutaraldehyde (HA-CA-glut) was better than that of the CA covalently immobilized on the glutaraldehyde preactivated HA support (HA-glut-CA). The thermostabilization factors (compared with the free enzyme) of these two immobilized enzymes were 11.2-fold and 2.2-fold, respectively. In order to improve the stability of HA-CA-glut, a novel strategy based on postimmobilization modifying with aminated molecules was developed to take advantage of the glutaraldehyde moieties left on the enzyme and support. The macromolecules, such as polyethyleneimine (PEI) and chitosan, had larger effects than small molecules on the thermal stability of the immobilized enzyme perhaps due to crosslinking of the enzymes and support with each other. The quaternary structure of the CA could be much stabilized by this novel approach including physical adsorption on aminated support, glutaraldehyde treatment, and macromolecule modification. The HA-CA-glut-PEI20000 (the HA-CA-glut postmodified with PEI Mw = 20,000) had a thermostabilization factor of 20-fold, and its substrate affinity (Km = 14.3 mM) was better than that of HA-CA-glut (Km = 33.4 mM). The half-life of the immobilized enzymes HA-CA-glut-PEI20000 under the CPC-catalyzing conditions could reach 28 cycles, a higher value than that of HA-CA-glut (21 cycles).

Construction and application of a stoichiometric displacement model for retention in chiral recognition of molecular imprinting.

To do an extensive investigation of the chiral recognition mechanism of the molecular imprinting technique, two kinds of enantio-selective molecularly imprinted polymers (MIPs), N-tert-butoxycarbonyl-L-tryptophan (N-Boc-L-Trp) and N-tert-butoxycarbonyl-L-tyramine (N-Boc-L-Tyr), were synthesized by photo-induced and thermal-induced polymerization, respectively, and were employed as the stationary phase in liquid chromatography. A stoichiometric displacement model for retention (SDM-R) was successfully constructed and applied to evaluate the chiral separation of the MIPs. The simulation results showed that the values of ln k' in the proposed SDM-R could be employed to characterize the efficiency of the MIP's total separation, and the value of n could be used to denote the space effect of the enantiomers interacting with the MIPs when the interaction between the solutes and MIPs was a hydrogen-bonding interaction. Further studies showed that the suitability of the MIP cavity structure mainly determined the chiral-recognition ability of the imprinting system, when a strong hydrogen-bond competitive solvent was added into the mobile phase.

Hydration of acrylonitrile to produce acrylamide using biocatalyst in a membrane dispersion microreactor.

In this work, a membrane dispersion microreactor was utilized for the hydration of acrylonitrile to produce acrylamide. Through observation using a microscopy, it was found that the acrylonitrile was dispersed into the continuous phase (the aqueous phase contains nitrile hydratase (NHase)) as droplets with a diameter ranged from 25 to 35 µm, hence the mass transfer specific surface area was significantly increased, and the concentration of acrylamide reached 52.5 wt% within 50 min. By contrast, in stirred tanks, the concentration of acrylamide only got 39.5 wt% within 245 min. Moreover, only a few amounts of acrylonitrile were accumulated in this microreactor system. Through optimizing the flow rate, the concentration of acrylamide reached 45.8 wt% within 35 min, the short reaction time greatly weakened the inhibition of acrylonitrile and acrylamide on the enzyme activity, which is suitable for prolonging the life of free cell.