To understand the role of endoplasmic reticulum (ER)‐stress in mice molar development, we studied Tmbim6 that antagonizes the unfolded protein response, using Tmbim6 knockout (KO) mice and in vitro ...organ cultivation with knocking down using small interfering RNA. During molar development, Tmbim6 is expressed in developing tooth at E14–E16, postnatal0 (PN0), and PN6. Mineral content in Tmbim6 KO enamel was reduced while dentin was slightly increased revealing ultrastructural changes in pattern formation of both enamel and dentin. Moreover, odontoblast differentiation was altered with increased Dspp expression at PN0 followed by altered AMELX localizations at PN5. These results were confirmed by in vitro organ cultivation and showed altered Bmp signaling, proliferation, and actin rearrangement in the presumptive ameloblast and odontoblasts that followed the altered expression of differentiation and ER stress‐related signaling molecules at E16.5. Overall, ER stress modulated by Tmbim6 would play important roles in patterned dental hard tissue formation in mice molar within a limited period of development.
Tmbim6 is involved in regulating endoplasmic reticulum (ER)‐stress. It plays an important role in the formation of patterned dental hard tissue in mice molar via modulation of ER stress in developing tooth.
Selective laser melting (SLM), used to fabricate metallic objects with high geometrical complexity, is currently of increasing interest to the fields of medicine and dentistry. SLM-fabricated ...products should have highly smooth surfaces to minimize the use of post-processing procedures such as finishing and polishing. This study investigated the effect of various laser process parameters (laser power, scan rate, and scan-line spacing) on the surface roughness of a Co–Cr dental alloy that was three-dimensionally (3D) constructed via SLM. Initially, a single-line formation test was used to determine the optimal laser power (200 W) and scan rate (128.6 mm/s) that resulted in beads with an optimal profile. During subsequent multi-layer formation tests, the 3D Co–Cr body with the smoothest surface was produced using a scan-line spacing of 100 μm. The findings of this study show that laser process parameters have crucial effects on the surface quality of SLM-fabricated Co–Cr dental alloys.
The objective of this study is to compare the shear bond strength (SBS) and the morphological characteristics and chemical compositions of the base surface of newly bonded and rebonded ceramic ...brackets with different mechanical retention bases. Sixty extracted human premolars were divided into the newly bonded and rebonded groups. Ceramic brackets with patterned, laser-etched, and particle-coated patterned bases were randomly bonded to the tooth samples in each group (n=10 per base type). The rebonded brackets exhibited significantly lower SBS than the newly bonded brackets (p<0.05). The main chemical composition of the brackets in both groups was aluminum on the energy-dispersive X-ray spectroscopy. Scanning electron microscopy imaging showed the presence of regular-shaped undercuts or irregular micro-undercuts on the bracket bases which mostly remained intact even after debonding and sandblasting, while coated particles disappeared. The rebonded ceramic brackets with mechanical retention bases exhibited clinically acceptable bond strength regardless of retentive forms.
MicroRNAs in eukaryotic cells are thought to control highly complex signal transduction and other biological processes by regulating coding transcripts, accounting for their important role in ...cellular events in eukaryotes. Recently, a novel class of bacterial RNAs similar in size 18–22 nucleotides (nt) to microRNAs has been reported. Herein, we describe microRNAs, small RNAs from the oral pathogen
Streptococcus sanguinis
. The bacteria are normally present in the oral cavities and cause endocarditis by contaminating bloodstreams. Small RNAs were analyzed by deep sequencing. Selected highly expressed small RNAs were further validated by real-time polymerase chain reaction and northern blot analyses. We found that skim milk supplement changed the expression of small RNAs S.S-1964 in tandem with the nearby SSA_0513 gene involved in vitamin B
12
conversion. We furthermore observed small RNAs secreted via bacterial membrane vesicles. Although their precise function remains unclear, secretable small RNAs may represent an entirely new area of study in bacterial genetics.
The aim of the present study was to determine the degree of surface staining and roughness of resin composites (RC) after finishing and polishing with different methods and immersion in three soft ...drinks.
A microhybrid, a nanohybrid, and a hybrid composite were selected. The specimens were prepared and divided into three groups of 36 after 24 hours, and designated as either unpolished or polished using Sof-Lex discs or Enhance point. Each group was further divided into three subgroups, immersed in distilled water, coffee, or cola for 1 week (N = 12). Color change (∆E) was measured by a spectrophotometer after each treatment. The ∆E was calculated using the following formula: ∆E = (∆L2+∆a2+∆b2)1/2. Surface roughness (Ra) was measured after 24 hours and 1 week. To observe the Ra, a scanning electron microscope was used.
A moderate correlation between Ra and ∆E was determined. Only coffee caused perceptible ∆E. The effect of Ra on staining was statistically significant (P < .05), but immersion in solutions for 7 days did not increase the Ra of RC.
The highest Ra values were obtained from hybrid RC. The Enhance point created the greatest roughness. Coffee was associated with the greatest ∆E for all materials and polishing methods.
The adhesion of porcelain to zirconia is a key factor in the success of bilayered restorations. In this study, the efficacy of a novel experimental liner (EL) containing zirconia for improved bonding ...between zirconia and veneering porcelain was tested. Four ELs containing various concentrations (0, 3.0, 6.0, and 9.0 wt %) of zirconia were prepared. Testing determined the most effective EL (EL3 containing 3.0 wt % zirconia) in terms of shear bond strength value (
= 15). Three different bar-shaped zirconia/porcelain bilayer specimens were prepared for a three-point flexural strength (TPFS) test (
= 15): no-liner (NL), commercial liner (CL), and EL3. Specimens were tested for TPFS with the porcelain under tension and the maximum load was measured at the first sign of fracture. The strength data were analyzed using one-way ANOVA and Tukey's test (
= 0.05) as well as Weibull distribution. When compared to NL, the CL application had no effect, while the EL3 application had a significant positive effect (
< 0.001) on the flexural strength. Weibull analysis also revealed the highest shape and scale parameters for group EL3. Within the limitations of this study, the novel ceramic liner containing 3.0 wt % zirconia (EL3) significantly enhanced the zirconia/porcelain interfacial bonding.
Root canal sealers should have good wetting and adhesion with intraradicular dentin. This study evaluated the wetting and adhesion properties of three bioceramic root canal sealers on dentin using ...contact angle (CA) measurements and calculations based on the Owens⁻Wendt⁻Rabel⁻Kälble (OWRK) model and compared the properties with those of a resin sealer. Three bioceramic sealers (EndoSequence BC Sealer (BC); Endoseal MTA (EM); and MTA Fillapex (MF)) were tested, together with one epoxy resin-based sealer (AH Plus (AP)). Disc-shaped sealer specimens and human premolar teeth with flat and polished intraradicular dentin surfaces were prepared (
= 12). The CAs of two liquids (water and methylene iodide) were measured on the surfaces using the sessile drop method. The wetting and adhesion properties of the four sealers were calculated using the wetting envelope and isogram diagram, respectively. Group BC showed the best wettability among the four sealer groups. The best adhesion was achieved for group EM, followed by group BC, with a significant difference being present between the two groups (
< 0.05). The OWRK-based calculation indicated that the bioceramic BC and EM sealers showed superior wetting and adhesion properties to the AP sealers.
The present study comprehensively compared the microstructure, flexural strength, and fracture toughness of zirconia ceramics prepared via two different methods, subtractive milling (SM) and ...stereolithography (SLA). Disc- or rectangular-shaped zirconia specimens (Prettau (SM) and 3DMix Zirconia (SLA)) were prepared following each manufacturer’s instructions and polished. The microstructures of the two different zirconia specimens were studied by scanning electron microscopy, X-ray diffractometry, energy-dispersive X-ray spectroscopy, and electron backscattered diffractometry. The flexural strength and fracture toughness based on the indentation fracture method were measured for the two different zirconia ceramics. A greater number of small pores and smaller grains were found in the SLA specimen than in the SM specimen. The crystal structure and microstructure analysis revealed that both ceramics had a similar phase composition to each other. No significant differences in flexural strength (p = 0.242) or fracture toughness (p = 0.101) were detected between the two ceramics. The mean flexural strength of the SLA-fabricated zirconia as well as the SM zirconia satisfied the class 5 criteria (>800 MPa) in the ISO 6872 standard.
This
study investigated whether different storage conditions of plasma-treated zirconia specimens affect the shear bond strength of veneering porcelain. Zirconia plates were treated with a ...non-thermal atmospheric argon plasma (200 W, 600 s). Porcelain veneering (2.38 mm in diameter) was performed immediately (P-I) or after 24 h storage in water (P-W) or air (P-A) on the treated surfaces (
= 10). Untreated plates were used as the control. Each group was further divided into two subgroups according to the application of a ceramic liner. All veneered specimens underwent a shear bond strength (SBS) test. In the X-ray photoelectron spectroscopy (XPS) analysis, the oxygen/carbon ratios of the plasma-treated groups increased in comparison with those of the control group. When a liner was not used, the three plasma-treated groups showed significantly higher SBS values than the control group (
< 0.001), although group P-A exhibited a significantly lower value than the other two groups (
< 0.05). The liner application negatively affected bonding in groups P-I and P-W (
< 0.05). When the veneering step was delayed after plasma treatment of zirconia, storage of the specimens in water was effective in maintaining the cleaned surfaces for optimal bonding with the veneering porcelain.
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