Antimicrobial effect and the mechanical and surface properties of a self-disinfecting and a chlorhexidine-incorporated Type IV dental stone.

STATEMENT OF PROBLEM: Stone casts are subject to contamination, but whether disinfectants incorporated into the stone are effective is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the antimicrobial activity and the mechanical and surface properties of self-disinfecting gypsum (SDG) and gypsum mixed with 2% chlorhexidine (GCHX). MATERIAL AND METHODS: Antimicrobial action was evaluated using the diffusion-disk technique on Streptococcus aureus and Candida albicans 1 hour and 24 hours after pouring the gypsum. The groups were SDG, GCHX, a positive control (PC) of gypsum mixed with distilled water, and a negative control (NC) of filter paper disk soaked with 2% chlorhexidine; n=8. Inhibition halos were measured using the ImageJ software program and statistically analyzed using the repeated measures mixed ANOVA with time×group interaction. Compressive strength (CS) in MPa and surface roughness (SR) in µm (parameters: Ra - roughness average; and Sa - 3-dimensional (3D) arithmetic mean of the surface profile) tests were performed to characterize the specimens (evaluated groups: SDG, GCHX, and PC; n=10). CS data were analyzed by a 2-way ANOVA with time×group interaction, and SR data by a 1-way ANOVA (α=.05). RESULTS: For S aureus, there were differences between GCHX and SDG at 1 hour and 24 hours (P<.05), but no significant differences were found for C albicans (P>.05). GCHX was better than PC, except for C albicans, and showed a reduction in CS when compared with PC and SDG (P<.05) at all time intervals. The SR of GCHX increased (Ra:1.76, Sa:2.08) when compared with PC (Ra:0.89, Sa:1.12) and SDG (Ra:1.03, Sa:1.35) (Ra: P<.004 and Sa: P<.001). CONCLUSIONS: The antimicrobial activity of GCHX against S aureus was better than that of SDG, but neither had an effect against C albicans. As for CS and SR, GCHX presented a decrease in properties when compared with PC and SDG but was within the American Dental Association #25 specification values.

Weight-loss and surface roughness of enamel after microabrasion procedure with different agents / Perda de peso e rugosidade da superfície do esmalte após procedimento de microabrasão com diferentes agentes

Introduction: Enamel microabrasion is achieved by abrasion of the enamel surface and it is a quick, practical and efficient procedure. Objective It was assessed the weight loss and surface aspect of enamel after microabrasion procedures with commercial and mixtures made in-office. Material and method Eighty bovine incisors were divided into four groups (n=10): OpalustreTM (6.6% HCl + silicon carbide); Whiteness RMTM (6% HCl + silicon carbide); 37% H3PO4 + pumice and 10% HCl + pumice. Treatment was performed by 15 applications of 10s duration. The enamel weight loss was determined by the difference in weight before and after the microabrasion. The surfaces were analyzed by a surface roughness equipment and scanning electron microscopy. Data were submitted to paired-T test, one-way ANOVA and Tukey tests (α=0.05). Result It was observed significantly weight loss for all groups. The difference in weight loss ranged from 0.037±0.012 for group 37% H3PO4 and from 0.054±0.009 for group 6,6% HCl. There was a significant increase in surface roughness for all groups and 10% HCl group showed the lower results (0.65±0.09). It was observed different patterns of enamel morphology by SEM images. Conclusion The in-office mixtures resulted in the lowest enamel structure loss (37% H3PO4) and the lowest surface roughness (10% HCl).

Introdução: A microabrasão do esmalte é realizada através da abrasão da superfície do mesmo, apresentando-se como um procedimento rápido, prático e eficiente. Objetivo Avaliar a perda de peso e o aspecto superficial do esmalte após procedimentos de microabrasão com agentes comerciais e não comerciais. Material e método Oitenta incisivos bovinos foram divididos em quatro grupos (n = 10): OpalustreTM (6,6% HCl + carboneto de silício); Whiteness RMTM (6% HCl + carboneto de silício); 37% H3PO4 + pedra-pomes e 10% HCl + pedra-pomes. O tratamento foi realizado em 15 aplicações de 10s de duração. A perda de peso do esmalte foi determinada pela diferença de peso antes e depois da microabrasão. As superfícies foram analisadas por equipamento de rugosidade superficial e microscopia eletrônica de varredura. Os dados foram submetidos ao teste T-pareado, ANOVA one-way e teste de Tukey (α = 0,05). Resultado Foi observada perda de peso significativa para todos os grupos, a diferença na perda de peso variou de -0,037±0,012 para o grupo 37% H3PO4 a -0.054±0.009 para o grupo 6.6% HCl. Houve um aumento significativo na rugosidade da superfície para todos os grupos e o grupo 10%HCl apresentou os resultados mais baixos (0,65±0,09). Foram observados diferentes padrões de morfologia do esmalte por meio de imagens MEV. Conclusão Os agentes não comerciais resultaram na menor perda de estrutura do esmalte (37% H3PO4) e na rugosidade superficial (10% HCl).

Effect of hydrochloric acid commercial presentation for microabrasion technique on loss of enamel structure and surface / Efeito da apresentação comercial de ácido clorídrico para técnica de microabrasão na perda de estrutura e superfície do esmalte

Introdução: A técnica de microabrasão pode ser realizada através de pasta pronta para uso, disponível comercialmente, ou o profissional pode manipulá-la no consultório. Objetivo: Verificar o efeito da apresentação comercial do ácido clorídrico a 10% na manipulação de pasta para microabrasão sobre a superfície do esmalte. Metodologia: Foram selecionados incisivos bovinos e divididos em dois grupos, de acordo com a apresentação comercial do ácido clorídrico (líquido ou em gel). O tratamento foi realizado através de dez aplicações com 10s de duração cada, intercaladas por lavagem de 10s. Vinte incisivos (n=10) foram utilizados para se determinar a perda de estrutura do esmalte. Cada amostra foi pesada, em balança analítica, antes e após submissão à microabrasão. Outras 20 amostras (n=10) foram utilizadas para determinação da rugosidade superficial média (Ra) utilizando-se um rugosímetro. Três amostras de cada grupo do experimento anterior foram selecionadas, aleatoriamente, e outras três amostras adicionais foram preparadas como controle (baseline) para análise em MEV. Resultados: Verificou-se diferença estatística significativa entre a massa final e a inicial e rugosidade superficial das amostras, independente da apresentação comercial do ácido. Nas imagens de MEV observou-se presença de superfície regular para o grupo controle (baseline). Nas demais imagens verificou-se superfície com considerável irregularidade e dissolução discreta do esmalte. Conclusões: O tratamento realizado causou perda significativa de estrutura e aumentou a rugosidade superficial dos espécimes, independente da apresentação comercial do ácido e sem apresentar diferença entre os grupos ao final. A apresentação comercial do ácido não parece ser um fator a interferir no tratamento. (AU)

Introduction: The microabrasion technique can be performed using a commercially available paste, or the dentist can prepare it in his office. Objective: To verify the effect of hydrochloric acid commercial presentation in the handling of microabrasion paste on the enamel surface. Methodology: Bovine incisors were divided into two groups, according to the commercial presentation of 10% hydrochloric acid (liquid or gel). The treatment was carried out through ten applications of 10 s duration each, intercalated with a 10s wash. Twenty teeth (n=10) were used to determine the loss of enamel structure. Each sample was weighed on an analytical balance before and after submission to microabrasion. Another 20 teeth (n=10) were used to determine the average surface roughness (Ra) using a rugosimeter. Three samples from each group of the previous experiment were selected, randomly, and another three additional samples were repared as a control (baseline) for SEM analysis. Results: There was a statistically significant difference between the final and initial mass and the surface roughness of the samples, regardless of the acid commercial presentation. In the SEM images, a regular surface was observed for the control group (baseline). In the other images, there was a surface with considerable irregularity and a slight dissolution of the enamel. Conclusions: The treatment carried out. (AU)

Influence of enhancement filters in apical bone loss measurement: A cone-beam computed tomography study.

BACKGROUND: The use of cone-beam computed tomography images (CBCT) providing a better assessment of bone injuries, although the sensibility of lesions measurement might be improved by the use of enhancement filters. Objective: This study aimed to analyze the influence of enhancement filters in apical bone loss measurement. MATERIAL AND METHODS: Eighteen CBCT cases randomly selected of apical bone loss were evaluated. The analyses were carried out following the evaluation in axial, coronal and sagittal protocols, using enhancement filters as Hard, Normal, and Very Sharp. The variables were statistically analyzed by Friedman and Wilcoxon test, Spearman's rho, and intraclass correlation coefficient. RESULTS: The differences between filters in axial and sagittal protocols were significant (p<0.05); however, this was not observed in the coronal slice. The use of Hard filter demonstrates better results than Very Sharp and Normal filter, improving significantly the bone loss measurement. A strong, significant and positive correlation was noted for all filters (with p< 0.001), such as a strong agreement between the variables, when the Normal filter was used as a reference. CONCLUSIONS: The use of enhancement filters increases the sensitivity of alveolar bone loss measurement, with relative advantage for Hard filter. Key words:Cone-Beam computed tomography. endodontics. periapical periodontitis. image enhancement. alveolar bone loss.

Correlação clínico-tomográfica em patologias dos seios maxilares: avaliação por meio de tomografia computadorizada por feixe cônico / Clinical and tomographic correlation in maxillary sinus pathologies: an evaluation by cone beam computed tomography

Objetivo: Analisar os achados tomográficos fortuitos em seios maxilares por meio de exames de Tomografia Computadorizada por Feixe Cônico, bem como sua correlação com a sintomatologia clínica relatada. Método: Exames da maxila de 54 pacientes foram avaliados por dois examinadores independentes considerando os seios maxilares direito e esquerdo (n=108). Foi verificada a ocorrência de patologias sinusais nas paredes anterior, medial, lateral e posterior, assoalho e teto dos seios maxilares, utilizando o software i-CAT Vision® (versão 1.6.20). Esses dados foram correlacionados com a presença ou ausência de sintomatologia relacionada à patologia sinusal. Resultados: O achado tomográfico mais observado foi a opacificação do seio pelo acúmulo de secreções (28,70%), seguido pelo espessamento da mucosa antral do seio maxilar (20,37%) e pela presença de cisto mucoso (17,59%). Em 60,22% dos casos não houve relato de sintomatologia clínica, independente da presença de patologias. A ocorrência de sintomatologia e achados tomográficos concomitantemente foi observada em 35,20% dos seios examinados, enquanto em 45,37% o achado tomográfico estava presente, sem, contanto, haver relato de sintomatologia. As paredes dos seios mais afetadas foram o assoalho (71,30%), correlacionando fator odontogênico associado, e a parede medial (57,40%), estando relacionada à frequência de infecções das vias aéreas superiores. O protocolo de visualização multiplanar obteve total acurácia e sensibilidade (100%), seguido pelos protocolos coronal (81,50%), e axial (76%).Conclusão: O exame de Tomografia Computadorizada por Feixe Cônico mostrou- se útil para definir a presença de patologias sinusais, porém é inespecífico na correlação dos achados em pacientes sintomáticos e na intensidade destes sintomas.

Objective: To analyze the eventual tomographic findings in maxillary sinuses by cone beam computed tomography as well as its relationship with the reported clinical symptoms. Method: Maxillary exams of 54 patients were evaluated by two independent examiners considering the right and left maxillary sinuses (n=108). There were sinus pathologies on the anterior, medial, lateral and posterior walls, the floor and ceiling of maxillary sinuses, detected with the i-CAT Vision® (version 1.6.20) software. The collected data were correlated with the presence or absence of symptoms related to the sinus pathology. Results: The most frequent tomographic finding was opacification of the sinuses by accumulation of sinusoidal secretions (28.70%), followed by thickening of the antral mucosa of the maxillary sinus (20.37%) and the presence of mucous cyst (17.59%). In 60.22% of the cases, there was no report of clinical symptomatology regardless of the presence of pathology. Simultaneous presence of symptoms and tomographic findings occurred in 35.20% of the sinuses, while in 45.37% there was a tomographic finding without reported symptomatology. The most affected sinus walls were the floor (71.30%), associated with odontogenic origin, and the medial wall (57.40%) associated with upper airway infections. The multiplanar visualization protocol resulted in complete accuracy and sensitivity (100%), followed by the coronal (81.50%) and axial (76%) protocols. Conclusion: Cone beam computed tomography was proven useful for detecting the presence of sinus pathologies, but it was unspecific in the correlation of the findings in symptomatic patients and in the intensity of these symptoms.