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Introduction. The aim of the present study was to evaluate, by atomic force microscopy (ATM), the surface condition and roughness parameters of low viscosity composite resins after exposure to Coca-Cola acidic drink under different immersion regimes. Materials and methods. The materials used in the present study were Filtek Ultimate Flowable Restorative(3M ESPE, St. Paul, MN, USA) and BrilliantFlow (COLTENE Whaledent, Switzerland). 20 cylindrical 5 mm in diameter and 2 mm thick samples were made from each material using plastic conformers placed on glass plates. The samples were light-cured for 40 s on both sides through the glass plates, to ensure complete polymerization of the material, then divided into two groups, as follows: Group I. Filtek Ultimate Flowable Restorative, and Group II. Brilliant Flow. Specimens from each group were then randomly divided into 5 subgroups: subgroup A, consisting of 4 control samples kept only in artificial saliva, and subsets B-E, consisting of 4 samples, one for each of the 4 immersion protocols in Coca Cola drink. The surface state of all samples was analyzed by atomic force microscopy and the roughness parameters were calculated. Results and discussion. The samples subjected to immersion in Coca-Cola were strongly corroded, compared to the control ones. The highest surface roughness value was determined for samples submerged 3 times/day in Coca Cola. Meantime, a higher Ra value was determined for the Filtek Ultimate Flowable composite than for Brilliant Flow. Conclusions. Evaluation of the surface condition of samples after immersion revealed in both materials a pattern of pitting corrosion, namely micro-holes and a preferential corrosion direction more obvious on the samples subjected to three immersions per day. [ABSTRACT FROM AUTHOR]

The recent development of bonding systems used in restorative dentistry has led to the introduction of new adhesive systems, characterized by adequate bonding strength, optimum adhesion to wet dentin and simplified application technique. The most effective products are characterized by removal or dissolution of the smear layer, demineralization of both dentin and enamel and resin infiltration into enamel micropores, dentin collagen matrix and opened dentine tubules. Self-etch adhesive systems have been developed in an attempt to combine increased adhesion and simplified technique. Although etching with phosphoric acid has been an accepted practice for several decades, being amply supported by numerous experimental and clinical studies, the new generations of adhesives aim at a major leap in concepts and technologies. The diversity of products available on the market and the variety of therapeutic protocols create confusion, making difficult to properly select and apply the appropriate adhesive system for each clinical case. In the absence of knowledge about the specific mechanisms of adhesion, practitioner's choice is random and the application is polluted by misconceptions. Preliminary etching may be required for a successful bonding of an adhesive system, yet it can jeopardize the outcome when using another product. Optimizing bonding in restorative dentistry still depends on understanding the mechanisms of adhesion and on applying rigorous techniques. Most important, the bonding system should not be randomly used but wisely chosen in order to adapt to the tissue particularities, specific stress, type of cavity and restorative technique. [ABSTRACT FROM AUTHOR]

The aim of the study was to evaluate the surface condition, after finishing and polishing with 3 different systems, of a flowable composite material, starting from the microstructure experimentally analyzed by atomic force microscopy. Materials and method. The material tested in the present study was Filtek Ultimate Flowable Restorative (3M ESPE) composite. 20 cylindrical samples, 5 mm in diameter and 2 mm thick, were prepared by using metallic molds. The samples were randomly divided into 4 groups: a group containing 5 control samples, not subjected to finishing and 3 groups formed, each, of 5 samples for each of the three finishing and polishing systems, respectively system 1: the two-step Sof-Lex (3M ESPE), system 2: multi-step Super Snap (Shofu, Inc. Kyoto, Japan) and system 3: multi-step OptiDisc (KerrHawe SA, Switzerland). The surfaces of the samples were analyzed by atomic force microscopy. For quantitative evaluations, the rugosity parameter (Ra), and the mean deviation of the determined profile were calculated. Results. All 3 polishing systems determined an increase of the Ra parameter, comparatively with the control samples; the highest mean Ra value, of 1.19 µm, was recorded for system 3, followed by system 2 (mean Ra value = 1.12 µm), while the lowest mean value, of 1.10 µm, was registered for system 1. Conclusions. All three systems under investigation induced increased rugosity on the surfaces of the samples prepared from the Filtek Ultimate Flowable Restorative (3M ESPE) composite resin. The most abrasive system appears to be OptiDisc (KerrHawe SA, Switzerland), followed by the Super Snap (Shofu, Inc. Kyoto, Japan) system, the one recording the lowest abrasion being Sof-Lex (3M ESPE). [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the variation of salivary micro-crystallization saliva index (IMK) in patients with gastroesophageal reflux desease, after utilisation of a remineralization product. Materials and method. Twelve patients suffering from gastroesophageal reflux were included in the study. Unstimulated saliva was collected in the same day and at the same hour for each patient. A total amount of 0.5 ml of unstimulated saliva was placed on a glass plate, dried for 30 min in a thermostate at +37oC, then analyzed on a Nikon Eclipse E 600 device. The images were saved and stored in a computer. The IMK index was determined using formula: IMK= none of the eye network points projected on crystals/none of the eye network points projected on the entire saliva drop. All patients were subjected to dental hard tissues remineralization using Recaldent MI Paste (GC Corporation) for 3 weeks, after which the IMK index was determined for each patient. Results. The appearance of crystals formed by saliva precipitation on the plates corresponds to one of these aspects: dendrite-shaped crystals, camomile flower, multiple points, micronetwork, cube or egg-shaped forms. The mean values of the IMK index varied from 0.4 before treatment to 0.9 after remineralization with Recaldent MI Paste. Conclusions. Recaldent MI Paste increased the remineralization capacity of saliva when applied to patients with gastroesophageal reflux disease. [ABSTRACT FROM AUTHOR]

The aim of the study was to compare the surface morphology of enamel and the variation of the mineral ions concentration after the manifestation of the erosive effect determined by various commercial beverages for athletes. 14 premolars extracted from orthodontic reasons have been cut in two halves. On each section, an enamel surface of 3×3 mm was preserved for investigations. The samples have been divided into 4 groups. In the control group, the 7 sections were kept in artificial saliva while, in the other 3 groups, the sections were introduced in 3 beverages for athletes: Gatorade Citron (Pepsi Cola Co.), 5-hour Energy (Living Essentials), Powerade Cherry (Coca Cola Co.). The samples were analyzed on an electronic microscope with Vega II LSH scanning device, coupled with EDX Quantax QX2 detector. SEM analysis evidenced erosion zones at the level of enamel, which appears pinched in the samples subjected to the action of acid beverages. A decreasing tendency of the average values of calcium ion concentrations was observed in the batches in which the enamel samples had been subjected to the action of beverages for athletes. The highest relative variations of calcium and phosphorous ions (10%, respectively 8%) were recorded for Gatorade, followed, in decreasing order, by Powerade, for which variations of 9%, respectively 6%, were noticed, and by the 5-hour Energy beverage, in which the relative losses were of 5%, respectively 3%. All beverages for athletes tested in the present study showed erosion potential upon the dental enamel. Gatorade appeared as the most aggressive beverage for athletes followed by Powerade and 5-hour Energy. [ABSTRACT FROM AUTHOR]

Aim. To determine the performance of the laserfluorescence method in the detection of early occlusal dental caries extended below the enamel-dentine junction related to different cut-off values. Materials and method. The in vivo study was performed on a sample group of 65 patients with 78 occlusal surfaces (molars) with enamel or dentine occlusal non-cavitated or microcavitary occlusal dental caries. The selected occlusal surfaces were examined by the ICDAS system (clinical exam) and the laser-fluorescence method (Diagnodent, KAVO), by a single examiner, with a 2 year-experience in the use of the ICDAS system and Diagnodent. The demineralisation depth was recorded after a minimal invasive intervention with a 330 bur. The sensitivity, specificity and accuracy of the cut-off values 20, 25, 30, 35 were determined according to the demineralization depth of enamel/dentine recorded after the minimal operative intervention. Results. The laser-fluorescence method, used to detect early occlusal dental caries extended below the enameldentine junction, gave the following sensitivity values: 0.93 for cut-off 20, 0.86 for cut-off 25, 0.69 for cut-off 30, 0.54 for cut-off 35, while the specificity values were: 0.80 for cut-off 25 and 1.00 for cut off 30 and 35. The accuracy of the diagnosis was 0.75 for cut-off 20, 0.83 for cut-off 25, 0.73 for cut-off 30, 0.60 for cut-off 35. Conclusions. The highest accuracy (0.83) of the laserfluorescence method was recorded for an optimal cut-off of 25. Significant statistical differences were found between the 25, on one side, and the 25 and 35 cut-off values, on the other. [ABSTRACT FROM AUTHOR]

The objective of the present investigation was to compare the precision of canal working length (Ll) measurements by electronic and radiological methods. Materials and method. The study was developed on a group of 122 anterior teeth of 118 patients, with ages between 23 and 58 years. The teeth were divided into 3 groups. The first one included 45 teeth, for which the working length was calculated with an electronic device (Apex Locator model iPex, NSK, Japan). In the second group of teeth (39 in all), the working length was calculated by the radiographic method of Ingle and, in the third one (38) - by the method of Bregman. When the technique of canal modeling was applied to all groups of teeth, a primary gutta percha cone (master) was positioned on the canal at the exact working length calculated for each tooth in part, after which an intra-oral radiography was made and the distance between the apical end of the master cone and the apical constriction was measured. Results. In group I, 91.1% of the Ll measurements were exact, and 8.9% of them were shorter, yet remaining within the limit of 2 mm versus the apical constriction. In group II, 71.7% of Ll were correctly measured, in 5.1% of the cases the calculated length was higher and in 23.2% of them the obtained values led to sub-obturation. Out of the inexact measurements, 44.4% evidenced the tip of the master cone within the limit of 2 mm versus the apical stricture. In group III, 60.5% of the measurements gave exact results, 13.1% of them - higher and 26.4%, respectively - lower. 53.8% of the cases of over- or sub-instrumentations occurred within the limit of 2 mm versus the apical constriction. Conclusions. The method for the calculation of working length with an electronic device of apical localization appeared as the most correct one, being followed by the radiographic technique of Ingle and by the method of Bregman. Application of the electronic method showed no case of apical over-instrumentation, while the sub-instrumentation cases were within the limit of the apical 2 mm, considered as accepted limits. The highest number of both over-instrumentation and sub-instrumentations was registered with the Bregman method. [ABSTRACT FROM AUTHOR]

Unlabelled: Aim of study is to compare the effect of etching with ortho-phosphoric acid on sound dentine, affected dentine and sclerotic dentine through AFM analysis., Material and Methods: The group study included 30 extracted third molars, 20 with acute and chronic carious lesions and 10 intact teeth. Teeth were sectioned in long axe to prepare sections with carious lesions surrounded by sound dentine. The sound teeth were sectioned to a depth of dentine comparable with carious lesions depth. The sections were etched with 37% ortho-phosphoric acid. The surface roughness was determined initially and after etching using AFM analysis. The results were expressed as relative variation of squared roughness., Results: The values of relative roughness indices were between 2.78 and 3 for sclerotic dentine, 3.18 and 3.26 for sound dentine, 3.32 and 3.38 for affected dentine. The highest values of roughness index were recorded for the affected dentine samples. Significant statistically values were recorded when comparing relative roughness indices for sclerotic dentine with relative roughness indices for affected dentine and sound dentine., Conclusions: clerotic dentine has significant higher resistance to the action of ortho-phosphoric acid than affected dentine and sound dentine. The lowest resistance to the action of etching agent was recorded for the affected dentine.

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.

Despite minimal invasive orientation in restorative dentistry, in Romania the necessary for extensive restorative treatment in posterior teeth is still high. The silver amalgam still remains a social treatment option for such situation. The purpose of this study was to analyze the efficiency of a new method for analytical determination of the volume of restoration in posterior teeth, knowing that the risk for coronal fracture depends on the size of restoration. The study correlated the results obtained through this method with the real values (mathematically determined) of restorations and the anatomical crowns volumes in order to assess the risk fracture. Amalgam restorations of different types and sizes were placed in 24 extracted premolars and molars. A good global correlation was observed between the true and calculated value (98.321%). The best correlation was observed for MOD restorations (93.042%) while the worst coefficient was obtained for MO restorations (83.378%). The medium restorations presented o correlation of 99.288% and the extensive restorations had an index around 96.957%. This method is based on physics principles and objective measurement resulting in a good correlation with the real dimensions of cavities. Therefore it could be used to assess the risk of crown fracture in teeth with amalgam restorations.

Unlabelled: The aim of the study was to asses the influence of the time, method and type of light curing on the compressive strength of dental composites. Dental composite resin (T-Econom, Ivoclar Vivadent) was cured for 10, 30 or 40 sec. with either a commercial conventional halogen light curing unit (LCU)--Hilux, (Benliodlu Dental Inc), or a light emitting diode (LED), LCU-Bluedent LED Smart. The compressive strengths were determined after 72 h on samples 3 mm in diameter and 7 mm high using FPZ 100/1 device., Results: The samples cured with LED LCU for 40 seconds in pulse mode showed the smallest values of compressive strength (245 MPa), while those cured with LED LCU for 40 seconds in ramp mode reached the highest values (295 MPa). Similar values for compressive strength were found for the samples polymerized with conventional halogen LCU and the samples cured with LED LCU in constant mode (283 MPa and 285 MPa, respectively)., Conclusions: Compressive strength depends on the light type and method. Tested LED curing light seems to induce similar compressive strengths as the halogen-based light. Using this conventional light curing unit requires at least 40 seconds of exposure in order to achieve adequate compressive strength. The LED light curing unit should be used in the ramp mode for at least 40 sec, followed by 10 sec in fast mode in order to achieve the best results.

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.

The aim of the study was to evaluate the possibility of using a fluoride product included in a biodegradable membrane in remineralization of initial enamel carious lesions. The membrane has anti-bacterial, anti-inflammatory and remineralization properties, with a long-term effect. The efficiency of this treatment was assessed by measuring the surface of the demineralization area and its depth. The results proved that the use of this membrane in association with remineralization therapy of the initial enamel carious lesions increase the chances of success and represents a simple solution easily accepted by the patients.

The recent improvement of adhesive materials should decrease the risk related to saliva contamination. The aim of this study was to evaluate the effect of saliva contamination on the microleakage within class V cavities restored with three different types of materials: conventional glass ionomer cement, composite resin and compomer. 30 human extracted teeth were randomly divided in 3 equal groups. In each group, class V cavities were prepared on both facial and lingual surfaces (but joint for glass ionomer cement and bevelled incisal margin for composite resin and compomer). The lingual cavities were contaminated with saliva prior to restoration, while the facial cavities were not contaminated, serving as control. After water storage for 24 hours, teeth were immersed in 1% methylene blue solution for 24 hours. The axial sections were viewed under an optical microscope and the extent of dye penetration along cervical, axial and incisal margins was measured in millimetres. Statistic analysis showed that under salivary contamination, microleakage increased along the cervical margin of restoration for all three tested materials. Saliva contamination resulted in microleakage within the axial wall of the cavity only for the conventional glass ionomer cement. These data indicate that composite resin and compomer used together with new adhesives seem to be less sensitive to saliva contamination compared to conventional materials. However, under saliva contamination, cervical microleakage cannot be completely prevented and proper isolation should still be mandatory.