Randomized Clinical Trial of ART Class II Restorations Using Two Glass Ionomer Cements: One-Year Follow-Up.

PURPOSE: The purpose of this study was to compare the survival rate of ART (atraumatic restorative treatment) Class II restorations in primary teeth, performed with glass carbomer cement and a high-viscosity glass ionomer cement, after 12 months. METHODS: One pediatric dentist placed 59 Class II ART restorations in 33 children (eight plus/minus two years old) of both genders. Two calibrated examiners, blinded to the type of material and not involved in the placement, evaluated the restorations at baseline, six, and 12 months. RESULTS: The overall success rate (95 percent confidence interval) at the six-month follow-up for the GP Glass Fill and Equia Fil was 69 percent (51 to 83) and 83 percent (66 to 93), respectively. No significant difference was detected between the study groups (Fisher's exact test, P=0.20). However, at 12 months, the overall success rates of both materials were 56 percent (37 to 73) and 86 percent (69 to 94), and this difference was statistically significant (Fisher's exact test, P=0.03). CONCLUSION: Class II ART restorations with glass carbomer showed lower survival rates after 12 months compared to those with high-viscosity glass ionomer cement.

Análise da dureza de um novo material restaurador para ART: Glass Carbomer / Analysis of the hardness of a new restorative material for ART: Glass Carbomer

Objetivo: Este estudo avaliou a microdureza de dois materiais ionoméricos - Glass Carbomer (GC-GCP Dental) e Riva Light Cure (RL-SDI) - em combinação com quatro unidades fotopolimerizadoras (Carbo LED lamp, GCP-Dental; Demi LED curing light, Kerr; Poli Wireless, Kavo; Radii Plus, SDI). Material e método: Foram confeccionados 80 corpos de prova seguindo a orientação dos fabricantes, sendo 40 para cada material ionomérico e, para cada 10 corpos de prova, uma das unidades fotopolimerizadoras foi utilizada. Após sete dias de armazenamento em água destilada e temperatura ambiente, os 80 corpos de prova foram submetidos ao teste de microdureza Vickers (microdurômetro HMV 2T). Cinco indentações foram realizadas em cada corpo de prova (centro, extremidades direita e esquerda, e superior e inferior). O ensaio foi realizado sob uma carga de 100 gramas, com tempo de penetração de dez segundos. Resultado: Independentemente da unidade fotopolimerizadora, o Riva Light Cure (RL-SDI) apresentou menor microdureza que o material Glass Carbomer (GC-GCP-Dental). A microdureza do Glass Carbomer (GC-GCP-Dental) foi influenciada pelo tipo de unidade fotopolimerizadora utilizada como fonte de calor. A análise de variância e o Teste de Tuckey (p< 0,05) mostraram que a interação dos fatores material vs.unidade fotopolimerizadora (p< 0,001) e os fatores principais material (p< 0,001) e unidade fotopolimerizadora (p=0,002) foram estatisticamente significantes. Conclusão: O material ionomérico Glass Cabomer (GCP- Dental) apresentou valor de microdureza significativamente superior quando comparado com o cimento de ionômero de vidro modificado por resina Riva Light Cure (SDI), independentemente da unidade fotopolimerizadora utilizada.

Objective: This study evaluated the microhardness of two encapsulated ionomer materials - Glass Carbomer (GC-GCP Dental) and Riva Light Cure (RL-SDI) in combination with four light curing units (Carbo LED lamp, GCP-Dental, Demi LED curing light, Kerr, Poli Wireless, Kavo, Radii Plus, SDI). Material and method: Eighty specimens were prepared following the manufacturer's guidelines, 40 for each ionomer material and for 10 specimens, one light curing unit was used. After 7 days of storage in distilled water and at room temperature, 80 specimens were tested with the Vickers hardness (microhardness HMV 2T, Shimadzu, Japan). Five indentations were performed on each specimen (center, right, left, top and bottom). The test was carried out under a load of 100 g, with a 10 second penetration time. Result: Independent of the curing unit the Riva Light Cure (RL-SDI) obtained the lower hardness than the material Glass Carbomer (GC-GCP-Dental). The microhardness of Glass Carbomer (GC-GCP-Dental) was influenced by the type of curing unit used as a heat treatment. The analysis of variance and Tukey test (p< 0.05) showed that the interaction of factors material vs. curing unit (p< 0.001), the main factor material (p< 0.001) and curing unit (p=0.002) were statistically significant. Conclusion: The ionomeric material Glass Carbomer (GCP-Dental) had significantly higher hardness value when compared with glass ionomer modified by resin Riva Light Cure (SDI), regardless of the light curing unit used.

Strength and wear resistance of a dental glass-ionomer cement with a novel nanofilled resin coating.

PURPOSE: To evaluate the influence of different resin coating protocols on the fracture strength and wear resistance of a commercial glass-ionomer cement (GIC). METHODS: A new restorative concept [Equia (GC Europe)] has been introduced as a system application consisting of a condensable GIC (Fuji IX GP Extra) and a novel nanofilled resin coating material (G-Coat Plus). Four-point fracture strength (FS, 2 x 2 x 25 mm, 14-day storage, distilled water, 37 degrees C) were produced and measured from three experimental protocols: no coating GIC (Group 1), GIC coating before water contamination (Group 2), GIC coating after water contamination (Group 3). The strength data were analyzed using Weibull statistics. Three-body wear resistance (Group 1 vs. Group 2) was measured after each 10,000 wear cycles up to a total of 200,000 cycles using the ACTA method. GIC microstructure and interfaces between GIC and coating materials were investigated under SEM and CLSM. RESULTS: The highest FS of 26.1 MPa and the most homogenous behavior (m = 7.7) has been observed in Group 2. The coated and uncoated GIC showed similar wear resistance until 90,000 cycles. After 200,000 wear cycles, the coated version showed significantly higher wear rate (ANOVA, P< 0.05). The coating protocol has been shown to determine the GIC fracture strength. Coating after water contamination and air drying is leading to surface crack formation thus significantly reducing the FS. The resin coating showed a proper sealing of GIC surface porosities and cracks. In terms of wear, the coating did not improve the wear resistance of the underlying cement as similar or higher wear rates have been measured for Group 1 versus Group 2.

Wear and morphology of infiltrated white spot lesions.

OBJECTIVES: To evaluate the toothbrush wear resistance of infiltrated artificial white spot lesions following two infiltration strategies, and to assess their ultramorphology. METHODS: Flat enamel surfaces from freshly extracted bovine teeth were polished and immersed in a Buskes demineralising solution for 30 days to create incipient caries-like lesions (white spots). Two experimental regions on the surface of each tooth were infiltrated with an infiltrant and a commercial etch-and-rinse adhesive. Toothbrush abrasion was applied for 20,000 cycles. Vertical wear loss of the infiltrated areas was measured after 10,000 and 20,000 cycles against unabraded and abraded enamel using confocal laser scanning microscopy (CLSM; multiple t-tests, α=0.05). Each lesion's surface and cross-section were evaluated under CLSM and scanning electron microscopy after etching and infiltration to assess ultramorphology. RESULTS: After 20,000 abrasion cycles, a statistically non-significant difference in vertical wear loss was measured for the infiltrant versus the adhesive compared with the original enamel (42.6±20.7 µm vs. 40.4±18.5 µm, p>0.05). Irregular surface profiles were common for the adhesive-infiltrated group as a result of peeling and blistering of the resin-covering layer. Ultramorphology of the infiltrated lesions revealed different patterns of penetration regarding density and depth. CONCLUSIONS: Although both infiltration strategies had equivalent wear resistance to toothbrush abrasion, surface and morphological aspects pointed to improved surface stability and infiltration quality for the infiltrant material.

Efeito de clorexidina em gel ou dentifrício nos níveis salivares de estreptococos do grupo mutans em crianças do distrito do Saí(São Francisco do Sul, SC, Brasil) / Effect of chlorhexidine gel or toothpaste in the salivary count of mutans streptococciin children of Saí district (São Francisco do Sul, SC, Brazil)

Introdução: A cárie dentária é a doença mais prevalente no ser humano, sendo caracterizada pela destruição progressiva dos dentes afetados. Para que ocorra são necessários um hospedeiro susceptível,uma microbiota bucal cariogênica, principalmente os estreptococos do grupo mutans (EGM), e um substrato adequado, os quais devem estar presentes por um período de tempo suficiente. Dos agentes antimicrobianos disponíveis para uso dentário, a clorexidina é um dos mais eficazes em reduzir a proporção de alguns microrganismos,especialmente os EGMs. Objetivo: O objetivo do estudo foi comparar aeficácia de duas formas de clorexidina a 1% (gel e dentifrício) aplicadas em escolares, sob escovação supervisionada, fora do ambiente deconsultório odontológico, na redução dos níveis salivares de EGM.Material e métodos: A amostra foi composta de 30 crianças e separada em dois grupos: grupo A (dentifrício) e grupo B (gel). As escovaçõesforam realizadas uma vez por semana durante quatro semanas consecutivas. Anteriormente à primeira escovação e 30 minutos após a escovação da quarta semana, realizou-se a coleta salivar. Foram preparadas diluições seriadas decimais das amostras de saliva atéa diluição 10-3. Amostras das diluições foram semeadas em meio de cultivo ágar Mitis Salivarius bacitracina sacarose (MSBS), seletivo aocrescimento de EGM. Resultados e conclusão: Após contagem das unidades formadoras de colônia de EGM, foi realizada a média das quadruplicatas para obter o valor de crescimento. Apenas o grupo dentifrício apresentou redução nos níveis salivares de EGM, não sendo estatisticamente significativa pelo teste t de Student (alfa = 0,05).

Introduction: Dental caries is the most prevalent disease affecting humans and it is characterized by the progressive destruction ofthe affected teeth. A susceptible host, a cariogenic oral microflora(mainly mutans streptococci) and a suitable substrate are necessary conditions for the development of caries. Chlorhexidine is one of the most effective antimicrobial agents available for dental use in reducing the proportion of some microorganisms, especially the mutans streptococci. Objective: The aim of this study was to compare theeffectiveness of two manipulated forms of chlorhexidine 1% (gel andtoothpaste) in reducing the salivary levels of mutans streptococci,which are used by schoolchildren in supervised toothbrushing, outsidethe dental clinic. Material and methods: The sample of 30 childrenwas divided into two groups: group A (toothpaste) and group B (gel).Applications were performed once a week for 4 weeks. Saliva samples were collected prior to the first brushing and 30 minutes after the lastone. Serial decimal dilutions of saliva samples were prepared up to10-3 dilution, and these samples were inoculated in Mitis Salivarius bacitracin sucrose agar, selective for growth of mutans streptococci.Results and conclusion: After counting the colony forming units of mutans streptococci, the average of quadruplicates was calculated so to obtain the growth value. Only the toothpaste group showed adecrease of the salivary levels of mutans streptococci although it wasnot statistically significant by Student t test (alpha = 0.05).