Effect of polyethylene fiber orientation on fracture resistance of endodontically treated premolars.

STATEMENT OF PROBLEM: Polyethylene fibers have been reported to improve the fracture resistance of endodontically treated teeth, but their optimal orientation is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the effects of different fiber positions and orientations on the fracture resistance of endodontically treated premolar teeth. MATERIAL AND METHODS: One hundred endodontically treated maxillary premolars were divided into 2 groups according to the cavity design, mesio-occluso-distal and occluso-buccal, and each group was divided into 5 subgroups (n=10) according to the polyethylene fiber orientation on the pulpal floor: unidirectional horizontal (from mesial to distal), unidirectional vertical (from buccal to palatal), bidirectional (buccopalatal and mesiodistal), circular (around the walls), and without fibers (control group). The cavities were restored with fiber-reinforced composite resin and conventional composite resin. All the teeth were fractured with a universal testing machine and analyzed as catastrophic failure or reparable failure. A 1-way ANOVA was used to compare fracture strength values (α=.05). RESULTS: The tested groups with different fiber orientations showed significantly higher fracture load than the control group (P<.05). No statistically significant difference was observed among the fiber orientations (P>.05). Most of the favorable fractures were occlusal to the cemento-enamel junction, and adhesive failure were seen in the mesio-occluso-distal and occluso-buccal cavities. The highest percentage of unfavorable fractures and mixed failures was observed in the control group. CONCLUSIONS: The fiber orientation pattern in the mesio-occluso-distal and occluso-buccal cavities did not differ significantly in the fracture resistance of endodontically treated maxillary premolar teeth.

Manejo odontológico en paciente con síndrome de Cornelia de Lange / Dental treatment of a patient with Cornelia de Lange syndrome

El síndrome de Cornelia de Lange (SCdL) es un trastorno genético poco frecuente y se atribuye principalmente a mutaciones en los genes NIPBL, SMC3 y SMC1A. Sus principales características clínicas son múltiples anomalías congénitas, dimorfismo facial, hirsutismo, hipertricosis, retraso psicomotor, discapacidad intelectual, restricción del crecimiento prenatal y postnatal, anomalías de manos y pies, así como malformaciones congénitas que afectan a distintos órganos. En pacientes con SCdL es necesario hacer hincapié en la higiene oral debido a la discapacidad intelectual que puede presentarse y asegurarse de que se realiza una adecuada valoración y saneamiento dental de forma periódica con el fin de prevenir enfermedades bucodentales. El objetivo de este reporte de caso es describir el manejo odontológico de un paciente de 10 años con SCdL y revisar las características clínicas y hallazgos radiológicos presentes en la cavidad oral (AU)

Cornelia de Lange syndrome (CdLS) is a rare genetic disorder and is principally attributed to mutations in the NIPBL, SMC3 and SMC1A genes. The main clinical characteristics are multiple congenital anomalies, facial dimorphism, hirsutism, hypertrichosis, psychomotor retardation, intellectual disability, prenatal and postnatal growth restriction, hand and foot anomalies, as well as congenital malformations affecting different organs. In patients with CDLS, it is necessary to focus on oral hygiene due to the intellectual disability that may be present and to ensure that adequate dental valuation and hygiene is routinely performed in order to prevent oral diseases. The aim of this case report is to describe the dental management of a 10-year-old patient with CDLS and review the clinical characteristics and radiological findings that are present in the oral cavity (AU)

Effect of degree of conversion on the surface properties of polymerized resin cements used for luting glass fiber posts.

STATEMENT OF PROBLEM: Lack of conversion of resin cements for luting glass fiber posts in deeper levels of the root canal may compromise clinical performance. PURPOSE: The purpose of this in vitro study was to evaluate the effect of the degree of conversion on the surface properties of dual-polymerized resin cements used for cemented glass fiber posts according to the root level. MATERIAL AND METHODS: Fifty maxillary central incisor teeth were endodontically treated, and glass fiber posts were cemented using the following systems: self-adhesive dual-polymerized resin luting cement (RelyX U200) and dual-polymerizing flowable core and a post luting system (Rebilda DC) with a self-etching adhesive (Futurabond DC). The degree of conversion was determined via attenuated total reflectance and Fourier transform infrared spectroscopy, and surface microhardness and cement film thickness were measured. The intraradicular fit was evaluated with microscopy. All tests were performed in the coronal, middle, and apical third of the root canal. Statistical analysis was done with ANOVA and the multiple comparison Tukey test (α=.05). RESULTS: The degree of conversion was higher in the coronal third using Rebilda DC (65.3 ±4.8%) than RelyX U200 (38.7 ±5.3%) (P<.05); on both resin cements, these values decreased from the coronal to the apical third (30.9 ±3.7%, 61.9 ±8.7%, respectively). The cement film thickness was higher for RelyX U200 in the 3 thirds than for Rebilda DC; significant differences (P<.05) were recorded in both cementing systems in the coronal and apical thirds. In the middle third, no significant differences were observed (P>.05). The mean surface microhardness values increased in the coronal thirds and decreased with increasing root canal depth. The marginal seal in the coronal thirds and the intraradicular fit in the middle thirds showed closer adaptation; however, some tags were observed in the interface resin cement and radicular dentin. Gap and tag formations were observed in the apical third. CONCLUSIONS: Depending on the root canal third, the surface properties of dual-polymerized resin cements are influenced by the degree of conversion.

Effect of short fiber-reinforced composite combined with polyethylene fibers on fracture resistance of endodontically treated premolars.

STATEMENT OF PROBLEM: Whether direct coronal restorations of endodontically treated teeth with short fiber-reinforced composite combined with polyethylene fibers provide adequate mechanical strength is unclear. PURPOSE: The purpose of this in vitro study was to compare the fracture strength of endodontically treated premolars with standardized mesio-occluso-distal (MOD) preparations restored with short fiber-reinforced composite (SFRC) combined with polyethylene Ribbond fibers (PRFs). MATERIAL AND METHODS: A total of 40 premolars were selected and distributed into 4 groups (n=10) as follows: group restored with SFRC (EverX Posterior), group restored with PRF (Ribbond fibers), and group restored with the combination PRF+SFRC, all followed by a conventional composite resin (IPS Empress Direct). MOD preparations and endodontic treatments were prepared except in the control group (intact teeth). MOD preparations and endodontic treatments were prepared except in the control group (intact teeth). Specimens were loaded using a universal testing machine until fracture occurred at a crosshead speed of 0.5 mm/min, and the failure type and fracture patterns was reported descriptively. The mean values of the groups were analyzed by using the Shapiro-Wilk test and 1-way ANOVA tests (α=.05). RESULTS: Restoration with PRF+SFRC provided the highest mean ±standard deviation fracture resistance (288.2 ±73.5 N). Restoration with just PRF had the lowest values (192.4 ±25.4 N), which were statistically different from those of SFRC and PRF+SFRC (P<.05). The predominant mode of failure was mixed, and all fracture patterns were favorable. CONCLUSIONS: Reinforcing endodontically treated premolars with MOD cavities with Ribbond fibers followed by a conventional composite resin enhanced fracture resistance and may be suitable for the direct coronal restoration of large posterior cavities in stress-bearing areas.

Antibiofilm properties of silver nanoparticles incorporated into polymethyl methacrylate used for dental applications.

BACKGROUND: Acrylic resins used in dental and biomedical applications do not have antimicrobial properties, their surface is susceptible to colonization of microorganisms. OBJECTIVE: The aim of this study was to evaluate the antibiofilm properties of silver nanoparticles (AgNPs) deposited in a polymethyl methacrylate (PMMA) surface against a Staphylococcus aureus biofilm. METHODS: The PMMA was impregnated with AgNPs by using the in-situ polymerization method. To determine the solubility of the incorporated silver (Ag+) atomic absorption spectrophotometry was used (AAS) at 24 h, 48 h, 7 days, and 30 days. Thirty specimens of PMMA with AgNPs and without NP (control group) were assembled in the CDC Biofilm Bioreactor system with a cell suspension of S. aureus. The specimens were removed at 6, 12, 24, 48, and 72 h to determine the viability profile and quantify the Arbitrary Fluorescence Units (AFU). RESULTS: The AgNPs showed an irregular and quasispherical shape with an average size of 25 nm. AAS analysis demonstrated a low solubility of Ag+. The formation of the S. aureus biofilm increased as the evaluation periods continued up to 72 h. The experimental group showed poor growth, and a decrease in the intensity of the fluorescence demonstrated a statistically significant inhibition of the formation of the biofilm (P < 0.05) in relation to the control group at 6, 12, 24, 48, and 72 h. CONCLUSION: AgNPs incorporated into PMMA decreased the growth and maturation of S. aureus biofilm.

Effect of microwave polymerization on the thermomechanical and surface properties of ocular prosthetic acrylic resins.

BACKGROUND: Polymerization conditions affect the physical-mechanical properties of acrylic resins used for craniofacial prostheses. OBJECTIVE: The aim of this study was to evaluate the effect of microwave polymerization on the thermomechanical properties and surface morphology of ocular prostheses fabricated with polymethyl methacrylate (PMMA). METHODS: PMMA discs were polymerized with microwave energy and with conventional heat polymerization (CHP) method. Ocular prostheses were fabricated to determine whether there were changes according to the polymerization method. The surface morphology and roughness were observed under SEM and AFM. The Vickers Hardness number (VHN) and flexural strength were measured. Thermal properties were evaluated with TGA/DSC, and chemical composition with FTIR. RESULTS: The PMMA acrylic resin polymerized with microwave energy showed a smooth surface with some relief areas. In the internal surface of the ocular prosthesis with microwave energy the PMMA is more compact. The mean roughness values were higher and statistically significant with CHP (P < 0.05), while the surface hardness and flexural strength were higher with microwave energy (P < 0.05). CONCLUSION: There were no changes in the calorimetry with either method, TGA showed an exothermic peak around 120 °C with CHP method. PMMA polymerized with microwave energy improved the mechanical and surface properties of the ocular prostheses.

Surface degradation and biofilm formation on hybrid and nanohybrid composites after immersion in different liquids.

PURPOSE: This study evaluated the association of surface degradation and formation of Streptococcus mutans (S. mutans) biofilm in resin-based composites (RBCs) after storage in different acidic liquids. METHODS: To evaluate microhardness and surface micromorphology, hybrid and nanohybrid RBC discs were stored in artificial gastric acid, cola drink, orange juice, artificial saliva, and distilled water for three intervals of 15 min per day for 7, 15, and 30 days. After 30 days of storage, surface roughness was analyzed, and the RBC discs were placed in a biofilm reactor inoculated with S. mutans to evaluate surface biofilm formation. RESULTS: As compared with nanohybrid RBCs, roughness and surface microhardness values were significantly lower (P < 0.05) for hybrid RBCs stored in artificial gastric acid, followed by specimens stored in cola drink and orange juice. Artificial gastric acid caused greater surface degradation, which increased the biomass of S. mutans on the surface of both RBC types. CONCLUSION: Surface degradation of hybrid and nanohybrid RBCs correlated with the pH of the liquid, while S. mutans biofilm formation was associated with increased surface roughness in hybrid RBCs.

3D-Printed Tubular Scaffolds Decorated with Air-Jet-Spun Fibers for Bone Tissue Applications.

The fabrication of instructive materials to engineer bone substitute scaffolds is still a relevant challenge. Current advances in additive manufacturing techniques make possible the fabrication of 3D scaffolds with even more controlled architecture at micro- and submicrometric levels, satisfying the relevant biological and mechanical requirements for tissue engineering. In this view, integrated use of additive manufacturing techniques is proposed, by combining 3D printing and air-jet spinning techniques, to optimize the fabrication of PLA tubes with nanostructured fibrous coatings for long bone defects. The physicochemical characterization of the 3D tubular scaffolds was performed by scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, profilometry, and mechanical properties. In vitro biocompatibility was evaluated in terms of cell adhesion, proliferation, and cell-material interactions, by using human fetal osteoblasts to validate their use as a bone growth guide. The results showed that 3D-printed scaffolds provide a 3D architecture with highly reproducible properties in terms of mechanical and thermal properties. Moreover, nanofibers are collected onto the surface, which allows forming an intricate and interconnected network that provides microretentive cues able to improve adhesion and cell growth response. Therefore, the proposed approach could be suggested to design innovative scaffolds with improved interface properties to support regeneration mechanisms in long bone treatment.

Effect of tricalcium silicate cements in gene expression of COL1A1, MAPK's, and NF-kB, and cell adhesion in primary teeth' pulp fibroblasts.

Tricalcium silicate cements (TSCs) regulate gene expression and cell responses from dental tissues surrounding the repair site. The study aimed to evaluate the gene expression levels of Collagen Type I Alpha 1 Chain (COL1A1), Mitogen-Activated Protein Kinases (MAPK's), Nuclear Factor-Kappa B (NF-κB), cell adhesion, and morphology of human dental pulp fibroblasts (hDPFs) from primary teeth treated with eluates obtained from Mineral Trioxide Aggregate (MTA) and Biodentine. hDPFs were treated with eluates from Biodentine and MTA (2.5 mg/mL in culture medium). The control group was a culture without the eluates. Gene expressions of COL1A1, MAPK's, and NF-κB were evaluated using Polymerase Chain Reaction (PCR) and cell adhesion by immunocytochemistry for Vinculin and Integrin ß1 expression. Gene expression of MAPK's and NF-κB in hDPFs with the eluates from MTA and Biodentine showed no significant difference versus the control group (p > 0.05), but COL1A1 exhibited a significant difference (p < 0.05). The expression of COL1A1, MAPK's, and NF-κB was lower in cultures with MTA and Biodentine eluates regarding the control group, with no significant difference between MTA and Biodentine (p > 0.05). After 72 h of incubation, the hDPFs cultured with MTA and Biodentine eluates showed an elongated morphology; after 7 d, a loss or/and reduction of the cytoplasmic processes, and smaller nuclei were observed. Vinculin and Integrin ß1 were expressed in hDPFs treated with MTA and Biodentine eluates. MTA and Biodentine did not inhibit or generate a significant difference in the expression levels of COL1A1, MAPK's, and NF-κB in hDPFs.

Effect of 4-Allyl-1-hydroxy-2-methoxybenzene (eugenol) in the expression of genes involved in cellular cycle and apoptotic process in dental pulp fibroblasts.

OBJECTIVE: This study sought to evaluate the effect of eugenol on the cell morphology and expression of genes involved in the apoptotic process in human dental pulp fibroblasts (hDPFs) from deciduous teeth. MATERIALS AND METHODS: hDPFs were cultured with 4 concentrations of eugenol (0.06 nM, 0.6 nM, 6 nM, 12 nM) and compared with a control group. After a 72 h incubation period, the cytotoxic effect on cell morphology by optical microscopy and gene expression by RT-PCR were evaluated. RESULTS: At 0.06 nM and 0.6 nM eugenol concentrations, vacuolisation of the cytoplasm was observed with atypical granulation of the hDPFs, and, at 6 nM and 12 nM cytoplasmic extensions disappeared almost completely. Casp-3, Casp-9, and telomerase genes were not expressed at the concentrations evaluated nor in the control group. The relative expression responses of Bcl-2 and TGF-ß genes were overexpressed at the 4 concentrations. MAKP's 0.06 nM (p < .001), 0.6 nM (p < .05) and 12 nM (p < .05) and Cyclin 1 at 12 nM showed significant difference versus the control group (p < .05). CONCLUSION: Eugenol is capable of causing morphological changes in hDPFs in a dose-dependent manner, higher concentrations may promote overexpression of apoptotic genes.

Analysis of the Mechanical Behavior and Effect of Cyclic Fatigue on the Implant-Abutment Interface / Análisis del comportamiento mecánico y efecto de la fatiga cíclica en la interface implante-pilar

ABSTRACT: Purpose: The seal of the interface formed at the implant-abutment connection is essential for the long-term success of the implant-supported restoration. The aim of this study was to analyze the mechanical behavior and the effect of cyclic fatigue before and after in the marginal fit of implant-abutment according to the manufacturing technique of the abutment. Materials and methods: Machined titanium abutments (DENTIS), cast abutments with Nickel-Chromium alloy (VeraBond II), and manufacturing custom milled Zirconia abutments (Zirkonzahn) were evaluated. The implant-abutment assemblies were subjected to cyclic loads of 133 N at a frequency of 19.1 Hz for 200,000 cycles. The microgap was measured using Scanning Electronic Microscope and the distribution of compressive stress by the three-dimensional Finite Element (FE) method. Results: The microgap measurement values of the machined abutments were 1.62μm and 1.92μm, cast abutments were 14.14 μm, and 28.44 μm, and the milled abutments were 14.18μm and 20.15μm before and after cyclic fatigue, respectively. Only the cast abutments and the machined abutments showed a statistically significant difference before and after cyclic fatigue (p≤0.05). The FE analysis showed that the critical areas of compressive stress were located at the implant-abutment connection, increasing in the cast abutments and decreasing in the milled and the machined abutments. Conclusion: Cyclic fatigue exerts an effect on the dimensions of the microgap at the implant-abutment interface before and after loading; this microgap depends of the type of abutment material and the manufacturing technique.

RESUMEN: Propósito: El sellado de la interface de la conexión implante-pilar es esencial para el éxito a largo plazo de la restauración implantosoportada. El objetivo de este estudio fue analizar el comportamiento mecánico y el efecto de la fatiga cíclica antes y después en el sellado de la conexión implante-pilar de acuerdo a la ténica de fabricación del pilar. Materiales y Métodos: Pilares mecanizados de titanio (DENTIS), pilares calcinables colados con aleación Niquel-Cromo (VeraBond II) y pilares fresados de Zirconia (Zirkonzahn) fueron evaluados. Los implantes y pilares atornillados se sometieron a una carga de 133 N a una frecuencia de 19.1 Hz durante 200 000 ciclos. El microgap fue medido con el Microscopio Electrónico de Barrido y la distribución del esfuerzo de compresión por el método tridimensional de Elemento Finito (EF). Los valores del microgap de los pilares mecanizados fueron de 1.62μm y 1.92μm, en los pilares calcinables fue de 14.14μm y 20.15μm, y los pilares fresados fue de 14.18μm y 28.44 μm antes y después de la fatiga cíclica, respectivamente. Los pilares calcinables y lo mecanizados mostraron diferencia estadísticamente significativa antes y después de la fatiga cíclica (p≤0.05). El análisis por EF mostró que las áreas críticas del esfuerzo de compresión estaban localizadas en la conexión implante-pilar, aumentando en los pilares calcinables y disminuyendo en los pilares fresados y en los mecanizados. Conclusión: La fatiga cíclica ejerce un efecto sobre las dimensiones del microgap en la interface implante-pilar antes y después de la carga cíclica; este microgap depende del tipo de material y de la técnica de fabricación del pilar.

Frequency of Pathogenic Microorganisms in Removable Orthodontic Appliances and Oral Mucosa in Children.

OBJECTIVE: The aim of this study was to evaluate the frequency of Staphylococcus aureus, Pseudomonas aeruginosa, and Candida species in removable orthodontic appliances (ROA) and the support oral mucosa in children. STUDY DESIGN: The study participants comprised 55 patients aged 6-12 years requiring ROA. The samples of biofilm colonization from the support oral mucosa and the ROA were taken prior to the use of the ROA (T0) and 4 weeks (T1) after ROA placement. The biofilm samples were seeded on chromogenic culture plates and incubated for 24-48 h. RESULTS: The microbial species evaluated were not present in either the support oral mucosa nor in the ROA at T0. After 4 weeks, P. aeruginosa was found in the support oral mucosa with a frequency of 60%, Candida spp. with 30.9% and S. aureus with 89.09%; in the ROA, P. aeruginosa with 67.7%, Candida spp. with 32.7%, while S. aureus with 90.9%. In the ROA were found C. glabrata in 15 cases, C. albicans in 14 cases, C. tropicalis in two cases, and C. krusei in one case. In the oral mucosa there were 10 cases of C. glabrata, 14 cases of C. albicans, one case of C. tropicalis, and 0 cases of C. krusei. CONCLUSIONS: The frequency of S. aureus, P. aeruginosa, and Candida spp. increased after the orthodontic treatment in either the ROA and or in the support oral mucosa. There is a direct relation between the use of the ROA and the increase of periodontal-pathogenic microorganisms.

Morphological and biological properties of silica nanoparticles for CRTC3-siRNA delivery and downregulation of the RGS2 expression in preadipocytes.

The aim of this study was to characterize the morphological properties of amorphous silica nanoparticles (SiO2 NPs), their cytotoxicity and intracellular location within Human Osteoblasts (HOB). Additionally, SiO2 NPs were explored for their effectivity as carriers of CRTC3-siRNA on Human Preadipocytes (HPAd), and thus downregulate RGS2 gene expression. SiO2 NPs were synthesized using the method of Stöber at 45 °C, 56 °C, and 62 °C. These were characterized via TEM with EDS, Zeta Potential and FT-IR. Cytotoxicity was evaluated by XTT at three concentrations 50, 100 and 500 µg/mL; SiO2 NPs intracellular localization was observed through Confocal Laser Scanning Microscope. Delivering siRNA effectivity was measured by RT-qPCR. Morphology of SiO2 NPs was spherical with a range size from 64 to 119 nm; their surface charge was negative. Confocal images demonstrated that SiO2 NPs were located within cellular cytoplasm. At a SiO2 NPs concentration of 500 µg/mL HOB viability decreased, while at 50 µg/mL and 100 µg/mL cell viability was not affected regardless SiO2 NPs size. SiO2 NPs-CRTC3-siRNA are effective to down-regulate RGS2 gene expression in HPAd without cytotoxic effects. The developed SiO2 NPs-CRTC3-siRNA are a promising tool as a delivery vehicle to control obesity.

Antimicrobial effect of gold nanoparticles in the formation of the Staphylococcus aureus biofilm on a polyethylene surface.

The main of this study was to evaluate the inhibitory effect on the in vitro formation of the Staphylococcus aureus biofilm formed on a polyethylene (PE) surface with a nanostructured Gold (Au) coating for medical devices. An experimental in vitro study was carried out using PE discs with an Au nanoparticle coating (AuNPs) on one side (experimental group) and without coating on the other (control group); the discs were mounted in the CDC biofilm reactor adding broth of yeast-dextrose-peptone (YPD) sterile culture inoculated with S. aureus in a cell suspension (5 × 108 cells/ml). The specimens were evaluated at different times (6, 12, 24, 48, 72 h) and stained with the Live/Dead Bacterial Viability Kit (Invitrogen) for observation, analysis, and quantification with confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The results showed that as evaluation time passed an increasing of S. aureus biofilm formation was observed in the control group, in the experimental group, a statistically significant biofilm inhibition was observed with respect to the AuNPs uncoated specimens (p ≤ 0.05) and showed a ratio of almost 4:1 viable/nonviable in the biofilm of the uncoated surfaces, with a difference > 5 Log10 in the CFU counts. The PE with AuNP coating showed an inhibitory effect on the biofilm formation of S. aureus.

Effect of Five Commercial Probiotic Formulations on Candida Albicans Growth: In Vitro Study.

PURPOSE: The objective was to evaluate the antagonistic effect of Lactobacillus and Bifidobacterium recovered from five commercial probiotics on the growth of C. albicans. STUDY DESIGN: The Lactobacillus and Bifidobacterium strains of five commercial probiotics were recovered and grown: Probio Hp+®, ProBiseis®, Lactipan®, Liolactil®, and Lacteol Fort®; 50 mg of each was hydrated and grown in Lactobacilli MRS (De Man, Rogosa and Sharpe) broth and incubated at 37°C with stirring (120 RPM) for 24 hours. Serial dilutions of 10-1 to 10-7 were made and viability was verified and quantified. For the antagonism tests, a suspension/inoculum of Lactobacillus strains recovered from each commercial preparation (4-30 × 109) and C. albicans ATCC 90028 (1.5-8 × 108) was prepared in MRS broth and incubated for 48 hours at 36°C, then plated on Dextrose Sabouraud Agar with Chloramphenicol and Rogosa Agar and the colony-forming units (CFU) were quantified. Additionally, viability was evaluated using the LIVE/DEAD® Yeast and Bacterial Viability kit. RESULTS: The probiotic that produced the highest acidity of the medium was Lactipan®, followed by Probiseis® and Liolactil®, while Probio Hp+® showed the least change. Probiseis® was determined to have the highest growth of probiotic bacteria and the highest inhibition on C. albicans, followed by Lactipan®; Liolactil® and ProbioHp+® showed the least effect. In fluorescence tests, ProBiseis® showed the best effect, followed by Liolactil® and Lactipan®; Probio Hp+® had less of an effect. CONCLUSIONS: Two commercial products (ProBiseis and Lactipan) whose formulations have L. acidophilus, L. casei, L. rhamnosus, L. plantarum, B. infantis, and S. thermophilus have a greater inhibitory effect on C. albicans ATCC 90028.

Evaluation of the Bond Strength and Marginal Seal of Indirect Restorations of Composites Bonded with Preheating Resin.

OBJECTIVE: Preheated resins (PR) are considered a cementing agent option for indirect adhesive restorations of composite inlays and onlays. The objective of this in vitro study was to evaluate the marginal sealing, adhesive interface, and microtensile bond strength of indirect adhesive restorations of composites in terms of dentin cemented with PR. MATERIALS AND METHODS: Standardized Class II preparations were performed on 30 extracted human premolars, impressions were taken, and indirect composite restorations were manufactured. In total, 15 restorations were cemented with PR (ENA HRi, SYNCA), and 15 restorations were cemented with self-adhesive resinous cement (RC) (Relyx U200, 3M ESPE), followed by a thermocycling regime. After that, these were segmented sagittally and longitudinally to evaluate the marginal sealing and the adhesive interface with scanning electron microscopy and confocal microscopy. Microtensile bond strength was assessed with a mechanical device (TA. XT Plus C, Stable Micro System). STATISTICAL ANALYSIS: Statistical analysis was conducted using the two-sample Student's t-test. RESULTS: The results showed that there is no statistically significant difference in the degree of microfiltration using PR or RC; however, microtensile bond strength is greater when the restoration is cemented with RC (278.75 N/cm3) than with PR (144.49 N/cm3), and better adjustment and sealing were observed for composite restorations with PR. CONCLUSION: PR comprise an alternative cementing agent for indirect composite restorations in Class II cavities in premolars.

Effect of dental restorative materials surface roughness on the in vitro biofilm formation of Streptococcus mutans biofilm.

PURPOSE: To evaluate Streptococcus mutans biofilm formation over different restorative dental materials. METHODS: Using a bioreactor over 72 hours, four commercially available ceramics were evaluated: IPS E-max Press, IPS E-max CAD, Lava Ultimate CAD-CAM, Vita Enamic and two resin composites (SR Nexco Paste and Brilliant NG). The results were evaluated using atomic force microscopy and confocal microscopy, the biofilm was stained and the arbitrary fluorescence units (AFU) quantified. RESULTS: The results showed that IPS E-max CAD had the lowest roughness values (4.29±1.79 nm), while the highest values were observed for Vita Enamic discs ( (77.13±17.35 nm). Analysis of S. mutans biofilm formation by AFU revealed lower values for IPS E-max CAD (6.77±1.67 nm); the highest values were found for Lava Ultimate (79.99±22.23 nm). Regarding the composite groups, SR Nexco Paste showed roughness values of 15.07±2.77 nm and lower arbitrary fluorescence units of 30.92±12.01 nm than Brilliant NT. There was a correlation between the surface roughness of ceramics and composite with S. mutans biofilm formation. CLINICAL SIGNIFICANCE: The adhesion of oral bacteria to restorative dental materials plays a key role in the success of dental treatment; the surface roughness influences the S. mutans biofilm formation.

Reinsertion of a fractured clinical crown as a biological restoration after dental trauma.

This clinical report describes the rehabilitation procedure of an upper central tooth with a coronal fracture without compromising the root. The treatment plan consisted of the reinsertion of the fractured fragment as a definitive cemented biological restoration. Due to the deficient remnant, a fiber-reinforced composite post was used. The objective of this clinical case was to report the biological behavior of the enamel and dentin of a biological restoration after dental trauma. Patient satisfaction with the treatment was achieved by continuing with the same tooth and biomimetizing the fracture line with conventional composites. Controls were conducted, and 1 year after dental trauma, no color changes in dental tissues and no inflammation in periodontal and soft tissues were observed.

Restorative Rehabilitation of a Patient with Generalized Non-Carious Cervical Lesions: Case Report / Rehabilitación restaurativa de un paciente con lesiones cervicales no-cariosas generalizadas: Reporte de un caso

ABSTRACT Non-Carious Cervical Lesions (NCCL) are a current problem of multifactorial origin that is associated with the loss of vertical occlusal dimension, hypersensitivity, loss of teeth, fractures, and many other pathologies that affect the masticatory function of the oral cavity. Identification of the etiological factors of NCCL comprises a key piece for the solution of the problem. Based on clinical scientific evidence related with the diagnosis, a restorative treatment must be planned according to the loss of dental structure in order to return function and aesthetics. The purpose of this case report was to describe a 54-year-old male patient who was diagnosed with generalized NCCL combined with occlusal vertical dimension loss. The protocol of the treatment process is described.

RESUMEN Las lesiones cervicales no cariosas (LCNC) son una problemática actual de origen multifactorial, la cual se ve asociada a la pérdida de dimensión vertical oclusal, hipersensibilidad, pérdida de dientes, fracturas y muchas otras patologías que afectan la función masticatoria de la cavidad bucal. La identificación de los factores etiológicos de las LCNC son piezas claves para la solución del problema. Basados en la evidencia científica clínica relacionado con el diagnóstico, se debe planificar un plan de tratamiento restaurativo que depende de la pérdida de la estructura dentaria para devolver la función y estética. El objetivo de este reporte de caso es describir a un paciente masculino de 54 años a quien se le diagnosticó LCNC generalizadas combinado con una pérdida de dimensión vertical oclusal. El protocolo de plan de tratamiento es descrito paso a paso.

Behavior of Mesenchymal Stem Cells Obtained From Dental Tissues: A Review of the Literature / Comportamiento de células mesenquimales obtenidas de tejidos dentales: Revisión de literatura

Abstract 20. The success of tissue engineering in combination with tissue regeneration depends on the behavior and cellular activity in the biological processes developed within a structure that functions as a support, better known as scaffolds, or directly at the site of the injury. The cell-cell and cell-biomaterial interaction are key factors for the induction of a specific cell behavior, together with the bioactive factors that allow the formation of the desired tissue. Mesenchymal Stem Cells (MSC) can be isolated from the umbilical cord and bone marrow; however, the behavior of Dental Pulp Stem Cells (DPSC) has been shown to have a high potential for the formation of bone tissue, and these cells have even been able to induce the process of angiogenesis. Advances in periodontal regeneration, dentin-pulp complex, and craniofacial bone defects through the induction of MSC obtained from tooth structures in in vitro-in vivo studies have permitted the obtaining of clinical evidence of the achievements obtained to date.

Resumen 24. El éxito de la ingeniería de tejidos en combinación con la regeneración de tejidos depende del comportamiento y la actividad celular en los procesos biológicos desarrollados dentro de una estructura que funciona como soporte mejor conocida como andamio o directamente en el sitio de la lesión. La interación célula-célula y célula-biomaterial son factores claves para la inducción a un comportamiento célular específico junto con factores bioactivos que permitan la formación del tejido deseado. Las células troncales mesenquimales (MSCs) pueden ser aisladas del cordón umbilical y de la medula ósea, sin embargo, el comportamiento de las células troncales de pulpa dental (DPSCs) han demostrado tener un alto potencial para la formación de tejido óseo e incluso han logrado inducir el proceso de angiogénesis. Avances en la regeneración periodontal, complejo dentino-pulpar y defectos óseos craneofaciales a travez de la inducción de MSCs obtenidas de estructuras de dientes en estudios in vitro-in vivo han permitido obtener evidencia clínica de los logros obtenidos hasta el momento.