The Impact of Simulated Gastric Acid and Toothbrushing on Surface Characteristics of Resin-Modified Glass-Ionomer Cements.

Background and Objectives: The aim of this in vitro study was to evaluate the effect of simulated gastric acid associated with toothbrushing on the surface condition of three resin-modified glass-ionomer cements (RMGIC). Materials and Methods: One hundred and sixty samples of each material were obtained and included in three study groups according to the tested material: Group I (Ionolux, VOCO GmbH, Cuxhaven, Germany); Group II (Vitremer, 3 M-ESPE, St. Paul, MN, USA); and Group III (Fuji II LC, GC Corporation, Tokyo, Japan). The samples were submersed in hydrochloric acid 0.01 M (pH 3.8) for 3 h and exposed to a toothbrushing procedure at a frequency of 10,000 cycles with medium and hard bristles immediately or 30 min after the acid attack. Profilometric measurements were performed by using a non-contact profilometer (Dektak XT, Bruker, Billerica, MA, USA) in order to assess the surface roughness. ANOVA and Bonferroni post hoc tests were used for the statistical analysis at a significance level of p < 0.05. Results: Exposure of RMGICs to the erosive effect of hydrochloric acid in association with toothbrushing 30 min after the chemical attack increased the surface roughness of all three RMGICs. Exposure of the three tested materials exclusively to the action of hydrochloric acid did not affect the surface roughness. Conclusions: One year of hydrochloric acid challenge associated with one year of toothbrushing with medium-hardness bristles performed 30 min after the acid attack increase the surface roughness of two of the three types of RMGIC tested (Ionolux and Fuji II LC).

[The influence of hygroscopic expansion on nanohybrid composite restorations]. / Influenta expansiunii higroscopice asupra restaurarilor realizate cu un compozit nanohibrid.

UNLABELLED: Hygroscopic expansion of resin materials is a common phenomena due to water adsorption into the resin matrix. This expansion is dependent upon the chemical structure of the material. Water sorption of resin dental material may contribute to stress release immediately after polymerization shrinkage has occurred. The aim of this study was to evaluate the influence of water storage on nanohybrid composite by assessment of marginal enamel sealing of restorations. MATERIAL AND METHOD: 30 human teeth extracted for periodontal or orthodontic reasons were used in these study. Cavities were prepared and restored using a nanohybrid composite (Ceramix Mono, Dentsply DeTrey) and a total-etch adhesive system (Prime&Bond NT, Dentsply DeTrey). The teeth were then randomly divided in three groups which were stored for various times in deionized water (one hour, 24 hours and 7 days). After the storage period, the teeth were immersed in methylen blue 1% for 24 h. Then specimens were axially cut and the dye penetration within the occlusal enamel interface was evaluated using optic microscope. RESULTS: Kruskal-Wallis test showed significant differences of dye penetration between the long-term hydrated groups and the group hydrated for only one hour (p < 0.05). The mean value of dye penetration decreased from 0.04 mm to 0.1 mm after water storage for both 24 hours and 7 days. However, good sealing in enamel margins of restorations was observed even without hydration. CONCLUSION: Our results confirm that nanohybrid composites used with total etch adhesives systems have good ability to seal the enamel margins and water sorption can improve this sealing.

[Evaluation of caries activity using the micro-crystallization saliva index (IMK)]. / Evaluarea activitatii bolii carioase cu ajutorul indicelui de microcristalizare salivara.

The dental decay activity of a patient can be evaluated with the help of certain indirect signs that reveal the dental decay risk elements. The quantity, buffer capacity, inorganic components of the saliva are important in the pathogenesis of dental decay. The micro-crystallization saliva test (IMK) may represent an important criterion on whose basis one obtains an evaluation of the re-mineralization capacity of saliva. The purpose of this study consisted in the calculation of the IMK index on a lot of patients and its correlation to the type of dental decay activity. The study was conducted on a lot of 30 patients with ages between 18 and 45, nursed and examined every 6 months during 18 months. The attention was focused on the following parameters: the index of micro-crystallization (IMK) and the dental decay activity, calculated as rate of appearance of new dental lesions within 18 months. As a result of investigations, the authors observed the following correlations to dental decay activity: the patients with IMK = 1/0.6 did not have any new dental lesion, in the patients with IMK = 0.6/0.4 new dental lesions appeared within 12-18 months and in the patients with IMK = 0.4/0 new dental lesions appeared in less than 6 months after examination. The IMK index--indicator of the re-mineralization capacity of saliva, may be evaluated using a relatively simple methodology, accessible and at a moderate price. Research pointed out that this index may be an useful instrument when evaluating the dental decay susceptibility of patients, contributing to the identification of the dental decay risk and consecutively to the choice of individualized prophylactic and therapeutic procedures.

[Clinical aspects of the evolution of dental caries and periodontal disease in patients treated with corticosteroids]. / Aspecte clinice ale evolutiei cariilor dentare si a bolii parodontale la bolnavii supusi corticoterapiei.

Patients treated with adrenal glucocorticoids may run a higher risk of dental caries, both as a result of their medical condition and of the physical and physiological effects of their pharmacotherapy. Our clinical study reports about patients treated with glucocorticoids who were also having an odonto-periodontal condition. They were examined and we found rampant caries and periodontal diseases. The slow evolution of asymptomatic periodontal disease encouraged destruction of teeth in root caries. The rampant caries were correlated with immunodeficiency and treatment of these caries must take into account the general treatment.