Germline PTCH1: c.361_362insAlu alteration identified by comprehensive exome and RNA sequencing in a patient with Gorlin syndrome.

Gorlin syndrome can be caused by pathogenic/likely pathogenic (P/LP) variants in the tumor suppressor gene PTCH1 (9q22.1-q31), which encodes the receptor for the sonic hedgehog (SHH) ligand. We present a 12-month-old boy clinically diagnosed with Gorlin syndrome who was found to have significantly delayed development, palmar pitting, palmar and plantar keratosis, short hands, frontal bossing, coarse face, hypertelorism, a bifid rib, misaligned and missing teeth, and SHH-activated medulloblastoma. Genetic testing, including a pediatric cancer panel and genome sequencing with peripheral blood, failed to identify any P/LP variants in PTCH1. Paired tumor/normal exome sequencing was performed, which identified a germline NM_000264.5 (PTCH1): c.361_362ins? alteration through manual review of sequencing reads. Clinical RNA sequencing further demonstrated an Alu insertion at this region (PTCH1: c.361_362insAlu), providing molecular confirmation of Gorlin syndrome. This finding exemplifies a unique mechanism for PTCH1 disruption in the germline and highlights the importance of comprehensive analysis, including manual review of DNA sequencing reads and the utility of RNA analysis to detect variant types which may not be identified by routine genetic screening techniques.

Cervical enamel projections from a periodontal perspective: A scoping review.

Cervical enamel projections (CEPs) represent a unique developmental and anatomical anomaly wherein the enamel structure extends apically beyond the cemento-enamel junction of the tooth. In this scoping review, the existing literature on CEPs was evaluated to delineate their characteristics, prevalence, predilection for specific teeth and surfaces, clinical significance, and management approaches. Searches were conducted on MEDLINE (PubMed), Cochrane Library, and Embase databases using the keywords "enamel projection(s)" or "ectopic enamel." In total, 24 studies meeting inclusion criteria were included in the review. The prevalence of CEPs varied widely (8.3%-85.1%), predominantly manifesting as grade I or grade III. Mandibular first and second molars exhibited a higher incidence of CEPs, with a notable predilection for buccal surfaces. The consensus in most studies was that CEPs are associated with localized periodontal diseases. Recommendations inclined toward the removal of ectopic enamel during periodontal surgery to enhance periodontal attachment formation. However, decision-making should involve careful consideration of the benefits and drawbacks based on individual circumstances.

Multivalent Polymer Nanocomplex Targeting Endosomal Receptor of Immune Cells for Enhanced Antitumor and Systemic Memory Response.

We have designed and synthesized linear polymer-based nanoconjugates and nanocomplexes bearing multivalent immunostimulatory ligands and also demonstrated that the synthetic multivalent nanocomplexes led to an enhanced stimulation of immune cells in vitro and antitumor and systemic immune memory response in vivo. We have developed hyaluronic acid (HA)-based multivalent nanoconjugates and nanocomplexes for enhanced immunostimulation through the combination of multivalent immune adjuvants with CpG ODNs (as a TLR9 ligand) and cationic poly(L-lysine) (PLL; for the enhancement of cellular uptake). The multivalent HA-CpG nanoconjugate efficiently stimulated the antigen-presenting cells and the multivalent PLL/HA-CpG nanocomplex also led to an enhanced cellular uptake as well as continuous stimulation of endosomal TLR9. The mice vaccinated with dendritic cells treated with the multivalent nanocomplex exhibited tumor growth inhibition as well as a strong antitumor memory response.

Atlantoaxial joint stabilization using patient-specific 3-D-printed drill guides and 3-D-printed titanium plates or polymethyl methacrylate is effective in toy-breed dogs.

OBJECTIVE: To report the clinical outcomes in toy-breed dogs with atlantoaxial instability (AAI) stabilized with patient-specific 3-D-printed titanium plates or polymethyl methacrylate (PMMA), both with the assistance of 3-D-printed drill guides. ANIMALS: 15 client-owned dogs undergoing surgical treatment for AAI between January 1, 2020, and October 31, 2022. METHODS: The clinical characteristics, diagnostic images, and neurological outcomes of 15 dogs treated for AAI using 3-D-printing technology were reviewed. Postoperative CT images were examined to evaluate the screw placement accuracy in the atlas and axis. Clinical outcomes, including postoperative neurological improvement and screw loosening, were evaluated in dogs treated with a patient-specific titanium plate and those treated with PMMA. RESULTS: Patient-specific titanium plates (7 dogs) and PMMA (8 dogs) were used for AAI stabilization. The mean follow-up period was 15.2 months (range 7 to 22 months). A reduction of the axis without vertebral canal violation was confirmed on postoperative CT in 14 dogs. The mean deviation from the preoperative planning ranged from 0.30 to 1.27 mm at the insertion and exit points of 84 screws using this method. The neurological grade had improved in each dog postoperatively and at the final follow-up. Screw loosening was noted in 4 dogs in the titanium plates groups without neurological deterioration. CLINICAL RELEVANCE: Patient-specific 3-D-printed drill guides and titanium plates or PMMA are effective for AAI stabilization in toy-breed dogs, providing accurate guidance.

LAP6/POLYKETIDE SYNTHASE A and LAP5/POLYKETIDE SYNTHASE B encode hydroxyalkyl α-pyrone synthases required for pollen development and sporopollenin biosynthesis in Arabidopsis thaliana.

Plant type III polyketide synthases (PKSs) catalyze the condensation of malonyl-CoA units with various CoA ester starter molecules to generate a diverse array of natural products. The fatty acyl-CoA esters synthesized by Arabidopsis thaliana ACYL-COA SYNTHETASE5 (ACOS5) are key intermediates in the biosynthesis of sporopollenin, the major constituent of exine in the outer pollen wall. By coexpression analysis, we identified two Arabidopsis PKS genes, POLYKETIDE SYNTHASE A (PKSA) and PKSB (also known as LAP6 and LAP5, respectively) that are tightly coexpressed with ACOS5. Recombinant PKSA and PKSB proteins generated tri-and tetraketide α-pyrone compounds in vitro from a broad range of potential ACOS5-generated fatty acyl-CoA starter substrates by condensation with malonyl-CoA. Furthermore, substrate preference profile and kinetic analyses strongly suggested that in planta substrates for both enzymes are midchain- and ω-hydroxylated fatty acyl-CoAs (e.g., 12-hydroxyoctadecanoyl-CoA and 16-hydroxyhexadecanoyl-CoA), which are the products of sequential actions of anther-specific fatty acid hydroxylases and acyl-CoA synthetase. PKSA and PKSB are specifically and transiently expressed in tapetal cells during microspore development in Arabidopsis anthers. Mutants compromised in expression of the PKS genes displayed pollen exine layer defects, and a double pksa pksb mutant was completely male sterile, with no apparent exine. These results show that hydroxylated α-pyrone polyketide compounds generated by the sequential action of ACOS5 and PKSA/B are potential and previously unknown sporopollenin precursors.

Management of complicated crown-root fractures using intentional replantation: two case reports.

The management of complicated crown-root fractures is a challenge. Intentional replantation with 180° rotation may be a useful procedure to overcome this problem. In Case 1, a 23-year-old woman with complicated crown-root fractured teeth #11, #21, and #22 was referred for treatment. All fractured teeth were extracted, rotated 180°, and replanted in a slightly extruded position. After 3 months, root canal treatment was completed and the final restorations fabricated. At the 18-month follow up, the patient was asymptomatic, the tooth was functional, and no root resorption was observed radiographically. At the 90-month follow up, slight cervical root resorption of tooth #11 was noted. In Case 2, a 27-year-old woman with a crown-root fractured tooth #21 was referred for treatment. Despite immediate repositioning of the coronal fragment and a 2-week stabilization with a wire splint, the coronal fragment remained separated from the apical tooth segment. The apical segment was extracted, rotated 180°, and replanted in a slightly extruded position. After 1 and 4 weeks, the root canal treatment was completed and the final restoration fabricated, respectively. At the 24-month follow up, the patient was asymptomatic and apical healing was completed.

A novel analysis of the formation and resorption changes in dental hard tissue using longitudinal in vivo micro computed tomography.

This study was to investigate the new analysis manner of dental hard tissue change using in vivo micro-computed tomography (CT) in rat. Scanning, registration, analyzing, and presenting method to track longitudinal in vivo micro-CT data on dental hard tissues were validated in murine models: formative, dentin thickness after direct pulp capping with mineral trioxide aggregate; resorptive, development of apical bone rarefaction in apical periodontitis model. Serial in vivo micro-CT scans were analyzed through rigid-registration, active-contouring, deformable-registration, and motion vector-based quantitative analyses. The rate and direction of hard tissue formation after direct pulp capping was datafied by tracing coordinate shift of fiducial points on pulp chamber outline in formative model. The development of apical periodontitis could be monitored with voxel counts, and quantitatively analyzed in terms of lesion size, bone loss, and mineral density in resorptive model. This study supports the application of longitudinal in vivo micro-CT for resorptive- and formative-phase specific monitoring of dental hard tissues.

Butyrate potentiates Enterococcus faecalis lipoteichoic acid-induced inflammasome activation via histone deacetylase inhibition.

Enterococcus faecalis, a Gram-positive opportunistic pathogen having lipoteichoic acid (LTA) as a major virulence factor, is closely associated with refractory apical periodontitis. Short-chain fatty acids (SCFAs) are found in the apical lesion and may affect inflammatory responses induced by E. faecalis. In the current study, we investigated inflammasome activation by E. faecalis LTA (Ef.LTA) and SCFAs in THP-1 cells. Among SCFAs, butyrate in combination with Ef.LTA markedly enhanced caspase-1 activation and IL-1ß secretion whereas these were not induced by Ef.LTA or butyrate alone. Notably, LTAs from Streptococcus gordonii, Staphylococcus aureus, and Bacillus subtilis also showed these effects. Activation of TLR2/GPCR, K+ efflux, and NF-κB were necessary for the IL-1ß secretion induced by Ef.LTA/butyrate. The inflammasome complex comprising NLRP3, ASC, and caspase-1 was activated by Ef.LTA/butyrate. In addition, caspase-4 inhibitor diminished IL-1ß cleavage and release, indicating that non-canonical activation of the inflammasome is also involved. Ef.LTA/butyrate induced Gasdermin D cleavage, but not the release of the pyroptosis marker, lactate dehydrogenase. This indicated that Ef.LTA/butyrate induces IL-1ß production without cell death. Trichostatin A, a histone deacetylase (HDAC) inhibitor, enhanced Ef.LTA/butyrate-induced IL-1ß production, indicating that HDAC is engaged in the inflammasome activation. Furthermore, Ef.LTA and butyrate synergistically induced the pulp necrosis that accompanies IL-1ß expression in the rat apical periodontitis model. Taken all these results together, Ef.LTA in the presence of butyrate is suggested to facilitate both canonical- and non-canonical inflammasome activation in macrophages via HDAC inhibition. This potentially contributes to dental inflammatory diseases such as apical periodontitis, particularly associated with Gram-positive bacterial infection.

Influence of irradiation distance on the mechanical performances of resin composites polymerized with high-irradiance light curing units.

BACKGROUND: The aim of this study was to evaluate the influence of increased irradiation distance on the flexural strength (FS), dentin micro-shear bond strength (µSBS), and the degree of conversion (DC) of bulk-fill flowable, conventional flowable, and packable resin composites. METHODS: The resin composites tested were Surefil® SDR™ (SDR), Filtek Z350 XT Flowable Restorative A2 shade (Z3F), and Filtek Z350 XT Universal Restorative A2 shade (Z3P). Specimens were cured at four irradiation distances (0, 2, 4, and 8 mm) with an Elipar DeepCure-S LED curing light for 20 s. FS tests were performed (n = 15) using bar-shaped specimens (8 mm × 2 mm × 2 mm) of the resin composites. µSBS tests were performed on the occlusal surfaces of extracted third molars from humans that were ground to expose dentin (n = 15). DC was measured by using Raman spectroscopy on the top and bottom surfaces of disk specimens (2-mm thick) (n = 3). To further investigate whether extended irradiation times could compensate for reduced irradiance, additional Z3P specimens were prepared, which were light-cured at 8-mm distances for 40 and 60 s and subjected to FS tests, µSBS tests, and Raman spectroscopy. Both two-way and one-way ANOVA were used for statistical analyses. RESULTS: Both FS and DC of Z3P specimens cured at an 8-mm distance were significantly lower than those cured at shorter distances (p < 0.05), whereas the FS and DC of the Z3F and SDR specimens were not significantly influenced by increasing distances. The µSBSs of the three types of resin composites reduced with increasing irradiation distances. The FS, µSBS, and DC of the Z3P specimen light-cured at 8 mm for 40 s were comparable to those of the Z3P specimen cured at 0 mm for 20 s. CONCLUSIONS: Increasing the irradiation distance to 8 mm can have a deleterious influence on mechanical performances, including the FS, DC, and dentin µSBS, of the resin composites polymerized with high-irradiance light curing units.

Different Mortality Risks of Long-Term Exposure to Particulate Matter across Different Cancer Sites.

Particulate matter (PM) air pollution has challenged the global community and the International Agency for Research on Cancer (IARC) classified airborne particulate matter as carcinogenic to humans. However, while most studies of cancer examined a single cancer type using different cohorts, few studies compared the associations of PM between different cancer types. We aimed to compare the association of long-term exposure to PM (PM10 and PM2.5) and cancer mortality across 17 different types of cancer using a population-based cohort in the Seoul Metropolitan Area (SMA), South Korea; Our study population includes 87,608 subjects (mean age: 46.58 years) residing in the SMA from the National Health Insurance Services-National Sample cohort (NHIS-NSC) and followed up for 2007-2015. We used the time-dependent Cox proportional hazards model to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs) of each cancer mortality per 10 µg/m3 increase in PM concentrations, after adjusting for individual and areal characteristics. During eight years of follow-up, 1487 people died with any of 17 cancer types. Lung cancer death was the highest, followed by liver and stomach cancer. Although we did not find the association for all cancer types, possibly because of limited cancer cases, HRs of PM2.5 were relatively high for lung, stomach, pancreas, non-Hodgkin's lymphoma, prostate, esophagus, oral and pharynx, and brain cancer mortality (HRs = 1.44-7.14). High HRs for pancreas, non-Hodgkin's lymphoma, esophagus, and oral and pharynx cancer were also seen for PM10; our findings suggest PM air pollution as a potential risk factor of cancer mortality for upper digestive tracts, mouth, pancreas, and non-Hodgkin's lymphoma in a highly urbanized population with high exposure to PM for a long time.

PpASCL, a moss ortholog of anther-specific chalcone synthase-like enzymes, is a hydroxyalkylpyrone synthase involved in an evolutionarily conserved sporopollenin biosynthesis pathway.

Sporopollenin is the main constituent of the exine layer of spore and pollen walls. Recently, several Arabidopsis genes, including polyketide synthase A (PKSA), which encodes an anther-specific chalcone synthase-like enzyme (ASCL), have been shown to be involved in sporopollenin biosynthesis. The genome of the moss Physcomitrella patens contains putative orthologs of the Arabidopsis sporopollenin biosynthesis genes. We analyzed available P.patens expressed sequence tag (EST) data for putative moss orthologs of the Arabidopsis genes of sporopollenin biosynthesis and studied the enzymatic properties and reaction mechanism of recombinant PpASCL, the P.patens ortholog of Arabidopsis PKSA. We also generated structure models of PpASCL and Arabidopsis PKSA to study their substrate specificity. Physcomitrella patens orthologs of Arabidopsis genes for sporopollenin biosynthesis were found to be expressed in the sporophyte generation. Similarly to Arabidopsis PKSA, PpASCL condenses hydroxy fatty acyl-CoA esters with malonyl-CoA and produces hydroxyalkyl α-pyrones that probably serve as building blocks of sporopollenin. The ASCL-specific set of Gly-Gly-Ala residues predicted by the models to be located at the floor of the putative active site is proposed to serve as the opening of an acyl-binding tunnel in ASCL. These results suggest that ASCL functions together with other sporophyte-specific enzymes to provide polyhydroxylated precursors of sporopollenin in a pathway common to land plants.

Investigation of characteristics as endodontic sealer of novel experimental elastin-like polypeptide-based mineral trioxide aggregate.

Although mineral trioxide aggregates (MTA) have been adopted as an endodontic sealer because of excellent sealing effect and bioactive property and been modified with improvement of its characteristics, the developed MTA sealers have not yet satisfied all the ideal requirements of endodontic sealers. The aim of this study was to assess the characteristics of elastin-like polypeptide (ELP)-incorporated MTA for use as an endodontic sealer and compare them with those of commercial MTA sealers. Two commercial MTA sealers and three experimental ELP-incorporated MTA sealers with 0.3, 0.4, and 0.5 liquid/powder (L/P) ratio for 10 wt% ELP liquid were evaluated. The push-out bond strength, flow rate, sealer penetrability and wash-out resistance were tested and the sealer-dentin interface was observed using a scanning electron microscope (SEM). Our study revealed the ELP-incorporated MTA sealer, especially in 0.4 L/P ratio, exhibited the higher push-out bond strength and flow rate (P < 0.05), and equal or superior sealer penetration and remarkable wash-out resistance compared to commercial MTA sealers. The groups of ELP-based experimental sealers also exhibited more intimate contact with dentin compared to the commercial MTA sealers. Our research will suggest the possible adoption of the ELP-incorporated MTA as endodontic sealer for clinical use.

Effect of bioactive glass addition on the physical properties of mineral trioxide aggregate.

BACKGROUND: The addition of bioactive glass (BG), a highly bioactive material with remineralization potential, might improve the drawback of weakening property of mineral trioxide aggregates (MTA) when it encounters with body fluid. This study aims to evaluate the effect of BG addition on physical properties of MTA. METHODS: ProRoot (MTA), and MTA with various concentrations of BG (1, 2, 5 and 10% BG/MTA) were prepared. Simulated body fluid (SBF) was used to investigate the effect of the storage solution on dentin remineralization. Prepared specimens were examined as following; the push-out bond strength to dentin, compressive strength, setting time solubility and X-ray diffraction (XRD) analysis. RESULTS: The 2% BG/MTA showed higher push-out bond strengths than control group after 7 days of SBF storage. The 2% BG/MTA exhibited the highest compressive strength. Setting times were reduced in the 1 and 2% BG/MTA groups, and solubility of all experimental groups were clinically acceptable. In all groups, precipitates were observed in dentinal tubules via SEM. XRD showed the increased hydroxyapatite peaks in the 2, 5 and 10% BG/MTA groups. CONCLUSION: It was verified that the BG-added MTA increased dentin push-out bond strength and compressive strength under SBF storage. The addition of BG did not negatively affect the MTA maturation reaction; it increased the amount of hydroxyapatite during SBF maturation.

Effect of Novel Bioactive Glass-Containing Dentin Adhesive on the Permeability of Demineralized Dentin.

This study aimed to evaluate the effect of a novel bioactive glass (BAG)-containing dentin adhesive on the permeability of demineralized dentin. Bioactive glass (85% SiO2, 15% CaO) was fabricated using the sol-gel process, and two experimental dentin adhesives were prepared with 3 wt% silica (silica-containing dentin adhesive; SCA) or BAG (BAG-containing dentin adhesive; BCA). Micro-tensile bond strength (µTBS) test, fracture mode analysis, field-emission scanning electron microscopy (FE-SEM) analysis of adhesive and demineralized dentin, real-time dentinal fluid flow (DFF) rate measurement, and Raman confocal microscopy were performed to compare SCA and BCA. There was no difference in µTBS between the SCA and BCA (p > 0.05). Multiple precipitates were evident on the surface of the BCA, and partial occlusion of dentinal tubules was observed in FE-SEM of BCA-approximated dentin. The DFF rate was reduced by 50.10% after BCA approximation and increased by 6.54% after SCA approximation. Raman confocal spectroscopy revealed an increased intensity of the hydroxyapatite (HA) peak on the dentin surface after BCA application. The novel BAG-containing dentin adhesive showed the potential of both reducing dentin permeability and dentin remineralization.

A pilot study on the association between job stress and repeated measures of immunological biomarkers in female nurses.

OBJECTIVE: To evaluate the immunosuppressive effects of job stress in female nurses, an 8-month longitudinal study was conducted at a major university hospital. METHODS: Four groups of ten subjects each were constructed to represent high versus low objective stress and high versus low subjective stress based on their responses to a job stress questionnaire and objective stress ratings of the hospital's work units. Number of white blood cells (i.e., T cells, B cells, and natural killer cells), and lymphocytic proliferation to mitogens (concanavalin A, phytohemagglutinin, and pokeweed) and toxoid (tetanus) were measured by flow cytometry and radioimmunoassay. Serum levels of hydrocortisol, IL-1ß, IFN-γ, and TNF-α, and salivary IgA were measured by enzyme-linked immunosorbent assay. The data were analyzed by repeated measures analysis of variance controlling for age and smoking. RESULTS: The level of white blood cells was lower among high objective stress group (median: 7,170/m(3); range: 5,386-10,057) compared with that among low objective stress group (8,063; 5,888-9,875) (P = 0.03), however, no other cellular blood variables were found to be significant. In terms of humoral immuno-biomarkers, the level of TNF-α was moderately lower among high objective stress group (1.7 ng/ml; 0.3-2.7) compared with that among low objective stress group (2.2; 0.5-3.5) (P = 0.07), whereas the level of total sIgA was significantly higher among higher objective stress group (72.9 end-point titer/mg/ml/min; 14.4-153.4) compared with that among low objective stress group (44.8; 9.9-123.8) (P = 0.02). CONCLUSION: The results of the study suggest that psychological job stress affects the levels of some immunological biomarkers in female nurses.

Biomechanical evaluation of acetabular cup implantation in cementless total hip arthroplasty.

OBJECTIVE: To report biomechanical properties of the Biologic Fixation System (BFX) acetabular cup impacted into a normal canine pelvis and to compare the effect of implant positioned to and beyond the medial acetabular wall. STUDY DESIGN: In vitro cadaveric study. ANIMALS: Hemipelves of mature, large-breed dogs (n=6). METHODS: For each dog, 1 hemipelvis was reamed to the depth of the acetabular wall (group A) and 1 was reamed an additional 6 mm after penetration of the medial cortex of the acetabulum (group B). The hemipelves were implanted with acetabular cups and loaded in compression through a matching femoral prosthetic component until failure. Specimen stiffness, and failure displacement, load, and energy were determined from load and displacement data and results between groups compared with a paired t-test. RESULTS: Mean failure load was greater in group A (3812 ± 391 N) than group B (2924 ± 316 N; P<.014). No other differences (P>.05) were observed between groups. Bone fracture (n=5) and cup displacement (1) occurred in group A whereas in group B there were 3 fractures and 3 cup displacements. CONCLUSIONS: Although medial placement of the BFX cup affected compressive failure loads, failure loads for both groups exceeded normal physiologic loads. CLINICAL RELEVANCE: Medial positioning of the acetabular cup does not appear to compromise acetabular implant-pelvic stability under normal physiologic loads. Because arthroplasty candidates often have abnormal acetabular architecture, mechanical properties of the cup placed in acetabula without a dorsal rim should be investigated.

Pulp regeneration with hemostatic matrices as a scaffold in an immature tooth minipig model.

Control of blood clotting in root canal systems is one of the most critical and difficult concerns for regenerative endodontics therapy (RET). The purpose of this study was to investigate the effects of using gelatin- and fibrin-based hemostatic hydrogels as a scaffold on pulp regeneration in a minipig model. Cell viability of human dental pulp stem cells cultured three-dimensionally in gelatin-based and fibrin-based scaffolds was evaluated by MTT and live/dead assay. RET was performed on 24 immature premolars with an autologous blood clot (PC), gelatin-based and fibrin-based hemostatic matrices (GM and FM), or without the insertion of a scaffold (NC). The follow-up period was 12 weeks. Radiographic and histologic assessments for pulp regeneration were performed. Gelatin-based scaffolds exhibited significantly higher cell viability than fibrin-based scaffolds after 15 days (P < 0.05). The PC and GM groups showed favorable root development without inflammation and newly mineralized tissue deposited in the root canal system, while FM group presented inflammatory changes with the continuation of root development. The NC group exhibited internal root resorption with periapical lesions. The application of GM in RET led to favorable clinical outcomes of root development without inflammatory changes compared to conventional RET. Our results suggest that GM may serve as a viable regenerative scaffold for pulp regeneration.

Effect of elastin-like polypeptide incorporation on the adhesion maturation of mineral trioxide aggregates.

The aim of this study was to investigate the effects of the incorporation of elastin-like polypeptide (ELP) on the adhesion maturation of mineral trioxide aggregates (MTA). Two types of ELPs (V125 and V125E8) were genetically synthesized. V125 consisted of 125 repeating pentapeptides (Val-Pro-Gly-Xaa-Gly) and V125E8 was functionalized with octaglutamic acid in the C-terminus of V125; both were diluted to 10 wt% in solution. Three 1.5 mm diameter holes in dentin discs were filled with MTA mixed with either a solution of ELP or deionized water. Push-out bond strength tests were performed following storage in simulated body fluid (SBF) for 1, 2, 4, and 8 weeks (n = 12). The interface between dentin and MTA was observed via scanning electron microscopy (SEM). The maturation of MTA was evaluated with a stereoscopic microscope and SEM. The incorporation of a specific ELP (V125E8) significantly increased the bond strength of MTA to dentin with regard to every maturation period (p < 0.05). The bond strength of MTA also significantly increased with a longer maturation time irrespective of ELP incorporation (p < 0.05). V125E8-incorporated MTA exhibited a more intimate interface with dentin compared to the other groups. More spindle-shaped crystal structures and thicker crystals were observed in all MTA mixtures as the storage duration increased even though V125E8 exhibited fewer crystal structures on the surface. Within the limitations of this study, the incorporation of V125E8 increased the adhesive properties of MTA and the maturation of MTA occurred regardless of ELP incorporation.

Effect of Etching Procedures on the Adhesion of Biofilm-Coated Dentin.

Oral biofilms coat all surfaces in the oral cavity including the exposed dentin surface. This study aimed to investigate biofilm removal by acid etching procedures and the effects of the residual biofilm on dentin surfaces on composite-dentin adhesion. Dentin discs were assigned to five groups: no biofilm formation (C); biofilm formation and no surface treatment (BF); biofilm formation and acid etching (BF-E); biofilm formation and acid etching followed by chlorhexidine soaking (BF-EC); and biofilm formation and rubbing with pumice, followed by acid etching (BF-RE). Biofilms were formed on saliva-precoated dentin discs by soaking the discs in Streptococcus mutans (S. mutans) suspension. Biofilm removal from the dentin surface was evaluated quantitatively and qualitatively by confocal laser scanning microscopy and scanning electron microscopy, respectively. To compare the bond strength of the biofilm-coated dentin discs with the surface treatments, specimens were assigned to four groups: no biofilm formation and acid etching (C-E); BF-E; BF-EC; and BF-RE. Assessments of the micro-shear bond strength and subsequent failure modes were performed. BF-E and BF-EC did not remove the biofilm, whereas BF-RE partially removed the biofilm attached to the dentin (p < 0.05). The bond strength of BF-RE was significantly higher than those of BF-E and BF-EC, but lower than that of C-E (p < 0.05). In conclusion, mechanical biofilm removal is recommended before etching procedures to enhance adhesion to the biofilm-coated dentin.

A Pilot Study of Chronological Microbiota Changes in a Rat Apical Periodontitis Model.

Apical periodontitis caused by microbial infection in the dental pulp is characterized by inflammation, destruction of the pulpal and periradicular tissues, and alveolar bone resorption. We analyzed the chronological changes in microbiota using a pyrosequencing-based approach combined with radiologic and histopathologic changes in a rat apical periodontitis model. During the three-week observation, the pulp and periapical area showed a typical progress of apical periodontitis. A total of 27 phyla, 645 genera, and 1276 species were identified. The root apex had a lower bacterial species diversity than the pulp chamber. Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria were dominant phyla in both the pulp chamber and root apex. Remarkably, bacterial communities showed a tendency to change in the root apex based on the disease progression. At the genus level, Escherichia, Streptococcus, Lactobacillus, Rodentibacter, and Bacteroidetes were dominant genera in the pulp chamber. The most abundant genera in the root apex were Bradyrhizobium, Halomonas, and Escherichia. The species Azospirillum oryzae increased in the pulp chamber, whereas the species Bradyrhizobium japonicum and Halomonas stevensii were highly observed in the root apex as the disease progressed. The experimental rat model of apical periodontitis demonstrated a relationship between the microbiota and the apical periodontitis progression.