Levy Anderson César Alves

In vitro evaluation of the microhardness of bovine enamel exposed to acid solutions after bleaching

Acid erosion is a superficial loss of enamel caused by chemical processes that do not involve bacteria. Intrinsic and extrinsic factors, such as the presence of acid substances in the oral cavity, may cause a pH reduction, thus potentially increasing acid erosion. The aim of this study was to evaluate the microhardness of bleached and unbleached bovine enamel after immersion in a soda beverage, artificial powder juice and hydrochloric acid. The results obtained for the variables of exposure time, acid solution and substrate condition (bleached or unbleached enamel) were statistically analyzed by the ANOVA and Tukey tests. It was concluded that a decrease in microhardness renders dental structures more susceptible to erosion and mineral loss, and that teeth left unbleached show higher values of microhardness compared to bleached teeth.

Shear bond strength of orthodontic brackets bonded using halogen light and light-emitting diode at different debond times

The aim of this in vitro study was to compare the photoactivation effects of QTH (Quartz-Tungsten-Halogen) and LED (Light-Emitting Diode) on the SBS (Shear Bond Strength) of orthodontic brackets at different debond times. Seventy-two bovine lower incisors were randomly divided into two groups according to the photoactivation system used (QTH or LED). The enamel surfaces were conditioned with Transbond self-etching primer, and APC (Adhesive Pre-Coated) brackets were used in all specimens. Group I was cured with QTH for 20 s and Group II with LED for 10 s. Both groups were subdivided according to the different experimental times after bonding (immediately, 24 h and 7 days). The specimens were tested for SBS and the enamel surfaces were analyzed according to the Adhesive Remnant Index (ARI). The statistical analysis included the Tukeys test to evaluate the main effects of photoactivation and debond time on SBS. The Chi-square test was used to compare the ARI values found for each group, and no statistically significant difference was observed. The debond time of 7 days for QTH photoactivation showed statistically greater values of SBS when compared to the immediate and 24 h periods. There was no statistically significant difference between the QTH and LED groups immediately and after the 24 h period. In conclusion, bonding orthodontic brackets with LED photoactivation for 10 s is suggested because it requires a reduced clinical chair time.

Determinant factors of malocclusion in children and adolescents with cerebral palsy

Introduction: Cerebral palsy (CP) is an encephalic static lesion characterized as a nonprogressive disorder of movements and posture with functional deficits that may favor the occurrence of various malocclusions. We looked for a possible association between overall functional impairment and malocclusion in this population. Methods: Seventy patients from the Center of Attendance for Special Needs Patients, ages 6 to 18 years and with a CP diagnosis, were involved in the research. The overall degree of functional impairment was assessed with the Gross Motor Function Classification System, and malocclusion was evaluated with the criteria established by the World Health Organization and selected occlusion characteristics. To test the associations, univariate and multiple logistic Poisson regression analyses were used, and prevalence ratio values were calculated. Results: Patients with limited or severely limited mobility (Gross Motor Function Classification of 4 or 5) (P = 0.003), parafunctional habits (P = 0.001), and a caregiver who was not the mother had 3 to 4 times more risk for open bite. Patients with dyskinetic CP are 4 times more likely to develop deepbite (P = 0.005). Conclusions: The results showed that the type of CP, the degree of motor involvement, and the presence of parafunctions are important factors to be considered to establish a correct diagnosis of malocclusion in persons with CP. HighlightsFunctional impairment and type of malocclusion may be related in patients with cerebral palsy.

ESTUDO DO METABOLOMA DE BIOFLUIDOS EM PACIENTES PEDIÁTRICOS NEFROPATAS E SUA ASSOCIAÇÃO COM A DOENÇA PERIODONTAL.

INTRODUCAO: Metabolomica e a tecnica que analisa metabolitos endogenos e exogenos de baixa massa molecular encontrados em biofluidos e tecidos. Diversos estudos tem mostrado a importância da saude bucal em pacientes com doenca renal cronica (DRC). OBJETIVO: Identificar e interpretar a funcao de metabolitos salivares e de urina de pacientes com DRC e sua possivel associacao com a doenca periodontal (DP). METODOS: 30 adolescentes e adultos jovens com DRC, 12-18 anos, cadastrados no CAPE /FOUSP e no ICrFMUSP, fizeram parte deste estudo. O grupo controle foi composto por 30 individuos clinicamente saudaveis. Os especimes clinicos foram coletados e armazenados a -80°C ate a realizacao da analise de cromatografia gasosa acoplada ao espectrometro de massa (GC-MS). no laboratorio Dempster da EPUSP. A analise periodontal foi realizada por meio do indice de higiene oral simplificado (OHI-S), sangramento a sondagem e profundidade de sondagem. RESULTADOS: As analises estatisticas foram realizadas por meio da analise de componentes principais (PCA), testes de Mann-Whitney e Kruskal-Wallis. A quantificacao relativa de cada metabolito mostrou maiores concentracoes entre pacientes com DRC sem DP e com DRC e com DP, de alanina (p<0.0001), glicina (p<0.0001), tirosina (p=0.021),serina (p<0.0001),prolina (p<0.0002),leucina (p<0.0003), citrulina (p<0.0001), arginina (p<0.0002), p-Cresol(p<0.0003) e acetofenona (p<0.0003). Grupos com DRC mostraram concentracoes alteradas de acidos carboxilicos e dimetilarginina. CONCLUSOES: Ambas as patologias estimulam o processo oxidativo sintetizando metabolitos que podem potencializar a severidade da DRC. Verificamos que, apesar do perfil metabolico ser diferente, alguns metabolitos sao compartilhados por todos os grupos.

Identification of microorganisms in biofluids of individuals with periodontitis and chronic kidney disease using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

RATIONALE Chronic kidney disease (CKD) and periodontitis (PD) are important health issues. There is a large variety of microorganisms related to the pathogenesis of periodontitis, and optimising the time and the cost of laboratory assays to detect these organisms is highly valuable in the medical field. METHODS Bacteria were isolated from saliva and oral biofilm of 30 adolescents and young adults with definite medical and dental diagnosis of CKD and PD, respectively, and proteins were extracted for microorganism identification by means of the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) technique. RESULTS The results showed that the most incident microorganisms were Actinomyces dentalis (43%), Acinetobacter ursingi (60%), Aggregatibacter actinomycetencomitans (60%), Corynebacterium argentoctens (63%), Staphylococcus aureus (93%), Streptococcus salivarius (97%) and Tannerella forsythensis (43%). The analysis of oral biofilm showed higher incidences for Actinomyces dentalis (33%), Acinetobacter ursingi (50%), Aggregatibacter actinomycetencomitans (50%), Corynebacterium argentoctens (70%), Pseudomonas aeruginosa (40%), Staphylococcus aureus (73%) and Streptococcus salivarius (87%). CONCLUSIONS Based on these results, we concluded that the MALDI Biotyper protocol proves useful as a rapid and reliable assay for distinguishing different microorganisms possibly related to CKD and PD. Copyright