Consensus on glass-ionomer cement thresholds for restorative indications.

OBJECTIVE: The aim of this paper is to present the results of a consensus meeting on the threshold property requirements for the clinical use of conventional glass-ionomer cements (GICs) for restorative indications. METHODS: Twenty-one experts on GICs evaluated the results of tests on mechanical and optical properties of 18 different brands of restorative GICs: Bioglass R [B], Chemfil Rock [CR], Equia Forte [EF], Gold Label 2 [GL2], Gold Label 9 [GL9], Glass Ionomer Cement II [GI], Ionglass [IG], Ion Z [IZ], Ionomaster [IM], Ionofil Plus [IP], Ionostar Plus [IS], Ketac Molar Easymix [KM], Magic Glass [MG], Maxxion R [MA], Riva Self Cure [R], Vidrion R [V], Vitro Fil [VF] and Vitro Molar [VM]. All experiments were carried out by a team of researchers from Brazil and England following strict protocols, under the same laboratory conditions throughout, and maintaining data integrity. RESULTS: There was consensus on: determining as primary properties of the material: compressive strength, microhardness, acid erosion and fluoride release, and as secondary properties: contrast ratio and translucency parameter, in order to rank the materials. Seven brands were below the thresholds for restorative indications: IZ, IM, IG, MA, VF, B and MG. CONCLUSIONS: Based on the primary properties adopted as being essential for restorative indications, the conventional restorative GICs that met the thresholds and could be considered suitable as long-term restorative materials were: EF, GI, GL9, KM, IP, GL2, IS, CR, V, VM and R. A decision-making process to select the best GIC must also include results from clinical trials. CLINICAL SIGNIFICANCE: This study provides a ranking of GICs that could be considered suitable as long-term restorative materials based on their main properties.

Translucency parameter of conventional restorative glass-ionomer cements.

OBJECTIVE: To evaluate the translucency parameter (TP) and contrast ratio (CR) of different conventional restorative glass-ionomer cements (GICs). MATERIALS AND METHODS: Eighteen brands of GICs were evaluated. Five disks of each material were made following ISO 9917-1. The luminous reflectance and Central Bureau of the International Commission on Illumination parameters of disks were evaluated using a colorimeter, against backings of white and black, to obtain the translucent parameter and contrast ratio of different brands of glass-ionomer cements. The correlation between translucency parameter and contrast ratio was assessed with the Pearson correlation test. The translucent and contrast ratio parameters values were submitted to the one-way ANOVA and Tukey test for multiple comparisons (p < 0.05). RESULTS: There was a strong inverse relationship between CR and TP (r2  = 0.94, p < 0.001). The contrast ratio decreased as translucency increased. There were significant differences in TP and CR among brands (p < 0.001). CONLUSIONS: GICs exhibit different translucency and contrast ratio behavior. Some brands of GICs presented very low TP and this condition would be unacceptable for areas with esthetic demands. In addition, TP and CR showed a strong linear relationship. CLINICAL SIGNIFICANCE: The results found in this study demonstrated that the knowledge of the translucency and CR of different conventional restorative GICs is important in order to guide clinicians in the selection of restorative GICs for anterior teeth.

Effects of the reinforced cellulose nanocrystals on glass-ionomer cements.

OBJECTIVE: Glass-ionomer cements (GICs) modified with cellulose nanocrystals (CNs) were characterized and evaluated for compressive strength (CS), diametral tensile strength (DTS) and fluoride release (F-). METHODS: Commercially available GICs (Maxxion, Vidrion R, Vitro Molar, Ketac Molar Easy Mix and Fuji Gold Label 9) were reinforced with CNs (0.2% by weight). The microstructure of CNs and of CN-modified GICs were evaluated by transmission electron microscopy (TEM) and by scanning electron microscopy (SEM) while chemical characterization was by Fourier transform infrared spectroscopy (FTIR). Ten specimens each of the unmodified (control) and CN-modified materials (test materials) were prepared for CS and DTS testing. For the fluoride release evaluation, separate specimens (n=10) of each test and control material were made. The results obtained were submitted to the t-test (p<0.05). RESULTS: The CN reinforcement significantly improved the mechanical properties and significantly increased the F- release of all GICs (p<0.05). The GICs with CNs showed a fibrillar aggregate of nanoparticles interspersed in the matrix. The compounds with CNs showed a higher amount of C compared to the controls due to the organic nature of the CNs. It was not possible to identify by FTIR any chemical bond difference in the compounds formed when nanofibers were inserted in the GICs. SIGNIFICANCE: Modification of GICs with CNs appears to produce promising restorative materials.

Two-year clinical evaluation of resin composite in posterior teeth: A randomized controlled study.

BACKGROUND: Clinical evaluations as fundamental method to prove the efficiency of restorative materials. AIM: This study evaluated the clinical performance of restorative systems during 2 years of clinical service. MATERIALS AND METHODS: This study assessed the clinical performance of restorative systems (Filtek Z250 and P60), during 2 years of clinical service, using the US Public Health Service system. The randomized and double-blind study comprising thirty volunteers. The restorations were evaluated at baseline, 6, 12, and 24 months. It was used the following criteria: marginal discoloration (MD), marginal integrity (MI), superficial texture (ST), wear (W), postoperative sensitivity (PS) and recurrent caries (RC). RESULTS: Statistic analysis was performed using Fisher's and McNemar's exact tests and Pearsons's Chi-square in a significance level of 5%. The results at baseline and 24 months for Group I were: MD - 100, 100%; MI - 100, 88.6%; ST - 100, 94.3%; W - 100, 94.3%; PS - 100, 100%; RC - 100, 100%, of alpha scores; Group II: MD - 100, 97.1%; MI - 100, 91.4%; ST - 100, 94.3%; W - 100, 91.4%; PS - 100, 100%; RC - 100, 100%, of alpha scores. It was observed no statistical difference in the evaluated criteria and period. CONCLUSIONS: After 24 months of evaluation, both restorative systems exhibited acceptable clinical performance.

Effect of hygroscopic expansion on the push-out resistance of glass ionomer-based cements used for the luting of glass fiber posts.

This study examined the contribution of hygroscopic expansion of glass-ionomer (GIC) and resin modified glass-ionomer (RMGIC) luting cements to the push-out resistance of fiber posts. Glass fiber posts were luted to post spaces using different cements. Experimental specimens were stored in water, while control specimens were desiccated and stored in mineral oil to eliminate water from intraradicular dentinal tubules and/or the external environment that could have contributed to hygroscopic expansion of the cements. Thin slice push-out tests revealed no difference in retention strengths of resin composite cements that were stored in water or oil. Conversely, GIC and RMGIC cements exhibited increased retention strengths after water sorption. As unfavorable cavity geometry is taxing to dentin bond integrity in root canals, a strategy that relies on increasing the frictional resistance to post dislodgement via delayed hygroscopic expansion of glass-ionomer based materials may be a more pragmatic approach to fiber post retention.

Occlusal caries detection: a comparison of DIAGNOdent and two conventional diagnostic methods.

OBJECTIVES: The aims of this study were: 1) to compare the DIAGNOdent readings for the detection of caries on three different macroscopically sound and intact occlusal surfaces for the baseline measurement; and 2) to compare this laser device with visual and radiographic inspection. METHODOLOGY: Forty-five extracted premolars and molar human teeth were cleaned with a pumice slurry. Then 74 sites were defined and radiographs were taken from each one. Three examiners performed the examinations and took the DIAGNOdent measurements. Sensitivity and specificity were calculated for each diagnostic system, as well as intra- and inter-examiner reproducibility using Kappa tests. The cut-off point for visual and radiographic inspection was 1-2, and for the DIAGNOdent the manufacturer's instructions were followed. RESULTS: No statistical difference was found for the three predefined sound sites used for baseline measurements with DIAGNOdent. The visual inspection showed high sensitivity; radiographic inspection and DIAGNOdent measurements showed low sensitivity and high specificity. The highest intra- and inter-reproducibility was found with the DIAGNOdent. CONCLUSION: The thickness of the enamel did not have any effect on the readings with DIAGNOdent. It was concluded that in a low prevalence sample, the visual inspection provided the highest proportion of true disease identified correctly, and DIAGNOdent provided the highest proportion of non-disease identified correctly.

Clinical evaluation of ceramic inlays and onlays made with two systems: a one-year follow-up.

PURPOSE: The aim of this study was to evaluate the clinical performance of ceramic inlays and onlays made with two systems: sintered (Duceram [D], DeguDent) and pressable (IPS Empress [IPS], Ivoclar-Vivadent) after 1 year. MATERIALS AND METHODS: Seventy-four restorations - 37 IPS and 37 D - were cemented in 34 patients. Twenty-four premolars and 50 molars received Class II cavity preparations, totaling 28 onlays and 46 inlays. The restorations were evaluated by two independent investigators at baseline, 6 months, and 1 year, according to modified USPHS criteria. Fisher and McNemar statistical tests were employed to assess the survival rate. RESULTS: After one year, 100% of the restorations were assessed and all the restorations were considered clinically excellent or acceptable. Among the analyzed criteria, only the following received "Bravo" ratings: marginal discoloration: IPS (24.32%), D (13.51%); marginal integrity: IPS (10.81%), D (8.11%); color match: IPS (5.41%), D (5.41%); surface texture: IPS (2.70%), D (10.81%). No "Charlie" or "Delta" scores were given to the restorations. CONCLUSION: Among the analyzed criteria, only marginal discoloration differed statistically significantly from the results of the baseline examination for IPS Empress ceramic restorations (p = 0.008). No significant differences were found between the two ceramics. The two ceramic systems demonstrated excellent clinical performance after a period of 1 year.

Clinical evaluation of the ART technique using high density and resin-modified glass lonomer cements.

PURPOSE: The aim of this study was to evaluate the performance of two different glass ionomer cements using the Atraumatic Restorative Treatment (ART) technique in permanent teeth. MATERIALS AND METHODS: A total of 473 ART restorations were placed in 208 schoolchildren (7-12 years of age) by two previously trained operators, using high density and resin-modified glass ionomer cements. All the restorations were photographed at baseline and the patients were asked about postoperative sensitivity. After a period of 8 months, 193 patients were present after recall and 428 restorations were evaluated and photographed. Two independent examiners carried out the evaluation. RESULTS: The results showed a success rate of 86.2% for occlusal restorations with Fuji IX and 88.4% for those restored with Fuji Plus. A total of 86.7% of the approximal restorations with Fuji Plus were also judged to be successful after 8 months. No association was found between the materials and the clinical performance of the ART restorations in class I cavities. CONCLUSION: The type of restorative material did not influence the success or failure rates in class I cavities within this period. Fuji IX showed promising performance for occlusal ART restorations and Fuji Plus is also a promising material for occlusal and approximal ART restorations.