Effect of different industrialized acid beverages on the surface roughness of flowable composite resins: in vitro study.

Flowable composite resins are materials available for restorations in pediatric dentistry. However, these materials are subject to dangerous effects in the oral environment caused by acids that deteriorate and increase their roughness. Therefore it is important to evaluate the effect of different industrialized acid beverages on the roughness of flowable composite resins. An in vitro experimental study, was done using a convenience sample of 132 discs of 5 mm diameter by 2 mm depth of four flowable materials (FF (Filtek™ Z350 XT Flowable), TNF (Tetric® N-Flow), PF (PermaFlo®) and GF (Grandio® Flow)) exposed to three beverages (CC (Coca-Cola), AJ (apple juice), and FM (fermented milk)) and incubated at 37 ºC for 0, 15 and 30 days. The roughness (average roughness (Ra) and maximum height of profile (Rz) parameters) was measured at different intervals of time with a profilometer. For the data analysis, one-way analysis of variance (one-way ANOVA) and repeated measures analysis of variance (Repeated measures ANOVA) tests were applied (p < 0.05). In the roughness test before immersion, no differences were observed within the groups, with maximum roughness values for Filtek™ Z350 XT Flowable and minimum for PermaFlo®. However, at 15 and 30 days of immersion, the groups showed significant differences depending on the immersion drink, except Grandio® Flow in apple juice and fermented milk. The flowable materials studied presented specific behaviors according to the immersion period and drink used. The Filtek™ Z350 XT Flowable showed a similar increase in surface roughness independently of the drink used. Grandio® Flow was the most stable material against surface roughness changes after beverage immersion.

Association between sociodemographic characteristics and level of knowledge about oral cancer among Mexican dental health professionals: a cross-sectional online survey.

BACKGROUND: A good level of knowledge in dentists is crucial for an early diagnosis of oral cancer (OC). In Latin America there are a few studies of OC knowledge among dentist, those has been performed in Brazil, Colombia, and Chile, and their results showed low level of OC knowledge. On the other hand, there is no publication in which the level of knowledge of dentists in Mexico has been addressed. Therefore, this study aimed to assess knowledge of OC and to determine the association of the level of knowledge with sociodemographic characteristics among dentists in Mexico. METHODS: A cross-sectional online survey was designed to obtain information via questionnaire. The questionnaire was developed in the Spanish language, and the content validity was determined. The study was conducted among Mexican dentists with a 23-item questionnaire that was designed to be anonymous. The sample size was calculated using the finite population formula. Based on the responses, the level of knowledge of OC was categorized as very low, low, regular, good, or excellent. Additionally, the association between sociodemographic characteristics and the level of knowledge about OC was evaluated. RESULTS: This research was conducted on a sample of 387 dentists. Most of the respondents were general dentists and worked in urban zones. The majority of dentists lacked a specialty (76.7%). Additionally, most of the respondents were students (44.2%). The level of knowledge of the participants was between regular and good (77.8%). On the other hand, concerning self-evaluation, most of the participants considered their knowledge of OC to be regular (50.6%). In addition, there was no association between sociodemographic characteristics and knowledge about OC. CONCLUSIONS: This research identified some weaknesses in most Mexican dentists' knowledge of OC.

Enamel demineralization model in primary teeth: Micro-CT and SEM assessments of artificial incipient lesion.

Many studies have analyzed different tooth demineralization models, which generate artificial incipient lesions; however, most of them are complex, slow, not clear and results could not be employed in both primary and permanent teeth because of chemical content differences among them. This study evaluates a demineralization model on primary enamel, under three incubation periods; quantifying artificial incipient lesions formation, and depth by micro-CT, complementing with SEM for morphological characterization. Sixteen healthy human anterior primary teeth extracted for prolonged retention and orthopedic/orthodontic reasons were included in this study, previous informed consent. The sample was randomly assigned to four groups n = 4: G_Control, G_2D, G_4D, and G_7D. Micro-CT and SEM were performed during two stages: before demineralization (BD) and after demineralization (AD). A t-student test was carried out to determine differences among groups (p ≤ .05). No incipient lesions were observed in control group. Artificial lesion depth was similar among experimental groups; values were from 38.16 ± 05.40 µm to 42.61 ± 04.75 µm. An amount of 14 to 17 artificial incipient lesions were formed per group, the extension and distribution were different for each incubation period. Five erosive lesions were produced in G_7D. All experimental groups were able to form incipient artificial lesions in primary enamel. SEM characterization revealed more pronounced changes on the enamel surface, as the days of immersion in the demineralization solution increased. The 4-day incubation period is the most recommended for the demineralization model, due to the formation of incipient lesions only and its extension, which facilitates their assessment.

The roughness of deciduous dentin surface and shear bond strength of glass ionomers in the treatment with four minimally invasive techniques.

The concept of minimally invasive technique in dentistry emphasizes conservative strategies in the management of caries, which results in less destruction of healthy tooth structure. The use of different techniques seems to interfere in the roughness of dentin and the mechanisms of adhesion with the restorative material. This study characterized the roughness of deciduous dentin surface treated with four minimally invasive techniques using profilometry, atomic force microscopy (AFM) and scanning electron microscopy (SEM); moreover, shear bond strength of Vitremer™ glass ionomer was determined. Samples were divided into four groups: G1_CB carbide bur, G2_PB polymer bur, G3_C Carisolv™, and G4_AA air abrasive. No differences were found between groups before and after treatment in the roughness. Samples treated with a carbide bur presented a smear layer; smart bur surface exhibited the remains of the material; G3_C Carisolv™ showed a rough surface, and air abrasive presented particle traces. Concerning the shear bond strength of Vitremer™ glass ionomer were not found differences after treatment (p > 0.05). It is concluded that roughness showed characteristic patterns derived from the technique used and the shear bond strength is not significantly affected after using any minimally invasive method.

Poly(3-hydroxybutyrate) graft copolymer dense membranes for human mesenchymal stem cell growth

Background: The use of novel materials as an artificial extracellular matrix for stem cell growth is a current strategy of increasing interest for regenerative medicine. Here, we prepare thermal-remolded membrane scaffolds from poly(3-hydroxybutyrate) grafted with 2-amino-ethyl methacrylate hydrochloride. However, it is unclear whether these membranes are useful for tissue engineering. Results: The mechanical properties, tribology, and morphology of the dense membranes were assessed. The results show that tensile strain at break and roughness of the compressed membrane decrease with increasing graft degree. Moreover, graft copolymer membranes showed lower resistance to scratching, greater degree of swelling and higher brittleness than un-grafted P(3HB) films. Thus, it effectively supports the growth of dermal fibroblast, as demonstrated by epifluorescence microscopy. Conclusions: It is concluded that the developed membrane can be properly used in is the restoration of skin tissue. How to cite: González-Torres M, Sánchez-Sánchez R, Solís-Rosales SG, et al. Poly(3-hydroxybutyrate) graft copolymer dense membranes for human mesenchymal stem cell growth.

Dens in dente y talón cuspídeo en un incisivo permanente: reporte de un caso y tratamiento preventivo / Dens in dente and cusp talon in a permanent incisor: report of a case and preventive treatment

Los dientes pueden presentar trastornos originados por factores externos o hereditarios que afectan su forma. Dens in dente es una anomalía durante el desarrollo que resulta en la invaginación del esmalte y dentina, en la cara lingual o vestibular, que puede extenderse profundamente dentro de la raíz. El talón cuspídeo es caracterizado por la proyección de una cúspide accesoria en el cíngulo de los órganos dentarios anteriores y la superficie oclusal de los posteriores. Se presenta el caso de una niña de 7 años de edad, con dens in dente y talón cuspídeo en el incisivo central superior derecho que provoca interferencia oclusal prematura, sin sintomatología. Se realizó desgaste gradual del talón cuspídeo, con aplicación de fluoruro de sodio. El diagnóstico temprano de anomalías dentales en pacientes pediátricos es la clave para un tratamiento conservador y preventivo para el adecuado funcionamiento masticatorio y estético del paciente (AU)

Teeth may have disorders caused by external or hereditary factors that affect their shape. Dens invaginatus is an anomaly during development that results in invagination of the enamel and dentin, lingual or vestibular surface, which can extend deeply into the root. Talon cusp is characterized by the projection of an accessory cusp in the cingulate area in anterior and occlusal aspects of the posterior teeth. We present a case of a 7 year old girl with dens invaginatus and talon cusp on the maxillary central incisor that causes premature occlusal interference, without symptomatology. The treatment employed were gradual wear of cuspal talon with several applications of sodium fluoride. Early diagnosis in pediatric patients is the key to a conservative and preventive treatment for a proper masticatory and aesthetic functioning of the patient (AU)