Ten-year survival of ART restorations in permanent posterior teeth.

This study evaluated the 10-year clinical performance of high-viscosity glass-ionomer cement placed in posterior permanent teeth by means of the Atraumatic Restorative Treatment (ART) approach. One operator placed 167 single- and 107 multiple-surface restorations in 43 high-risk caries pregnant women (mean decayed teeth = 9.8 ± 5.5). Examinations were performed at 1-, 2-, and 10-year intervals according to ART criteria. In the last evaluation, the US Public Health Service (USPHS) criteria were also used. After 10 years, 129 restorations (47.1%) were evaluated and achieved a cumulative survival rate of 49.0% (SE 7.2%). The 10-year survival of single- and multiple-surface ART restorations assessed using the ART criteria were 65.2% (SE 7.3%) and 30.6% (SE 9.9%), respectively. This difference was significant (jackknife SE of difference; p < 0.05). Using the USPHS criteria, the 10-year survival of single- and multiple-surface ART restorations were 86.5% and 57.6%, respectively. The primary causes of failure were total loss (9.3%) and marginal defects (5.4%). The survival rates observed, especially for the single-surface restorations, confirm the potential of the ART approach for restoring and saving posterior permanent teeth.

Dental caries spectrum profile in Brazilian public school children and adolescents.

Dental caries remains a major public health problem, with a higher prevalence among in adolescence. The present study aimed to assess the dental caries spectrum profile in children and adolescents in Brazilian public schools. A cross-sectional study was performed in two public schools in Brazil to examine the permanent teeth of children and adolescents. The dental caries were assessed by applying the Caries Assessment Spectrum and Treatment (CAST) instrument, and the results were distributed as per disease status (healthy/codes 0-2; pre-morbidity/code 3; morbidity/code 4-5; severe morbidity/codes 6-7; mortality/code 8) and by severity as per the CAST-F1 formula (no severity, mild, moderate, and severe). The CAST data were described by age groups (8-9 y, 10-11 y, 12-13 y, 14-15 y, 16-17 y, and 18-19 y). The Kruskal-Wallis test was used to investigate differences in CAST prevalence and severity among the groups (p < 0.05). Total 598 students were enrolled. Most of the subjects were male (53.34%) and belonged to the age group of 12-13 y (34.95%). The variables CAST 0/1 (p = 0.024), CAST (p = 0.024), and CAST-F1 (p = 0.029) showed significant differences among age groups, and the post hoc test showed the differences in these variables as per the age groups of 14-15 y and 16-17 y (CAST 0/1, p = 0.047; CAST, p = 0.047; CAST-F1, p = 0.033). The dental caries spectrum increased from 8 to 19 y with a peak in the prevalence and severity in the middle of adolescence.

A prospective and randomized clinical trial evaluating the effectiveness of ART restorations with high-viscosity glass-ionomer cement versus conventional restorations with resin composite in Class II cavities of permanent teeth: two-year follow-up.

OBJECTIVE: To compare the effectiveness of ART restorations using High Viscosity Glass-ionomer cement (HVGIC) with conventional restorations using resin composite in Class II cavities of permanent teeth, in a 2-year follow-up. METHODOLOGY: Seventy-seven restorations were made with each restorative material, Equia Fil-GC Corporation (ART restorations) and Z350-3M (conventional restoration), in 54 participants in this parallel and randomized clinical trial. Restorations were evaluated at 6 months, 1 and 2 years using the ART and the modified United States Public Health Service (USPHS) criteria. Chi-square test and Survival Analysis (p<0.05) were used for statistical analysis. RESULTS: The success rates for ART restorations were 98.7% (6 months) and 95.8% (1 year) for both criteria. At 2 years, success rate was 92% and 90.3% when scored by the modified USPHS and ART criteria (p=0.466), respectively. The success rates for conventional restorations were 100% (6 months), 98.7% (1 year) and 91.5% (2 years) for both assessment criteria. ART restorations presented a lower survival rate by the criterion of ART (83.7%) when compared to the modified USPHS criterion of (87.8%), after 2 years (p=0.051). The survival of conventional restorations was 90.7% for both evaluation criteria. CONCLUSION: At the 2-years follow-up evaluation, no statistically significant difference was observed between the success rate of ART restorations with HVGIC compared to conventional restorations with resin composite in Class II cavities of permanent teeth.

Direct resin composite restorations versus indirect composite inlays: one-year results.

AIM: The aim of this study was to evaluate the clinical performance of direct resin composite restorations (Tetric Ceram-TC) and indirect composite inlays (Targis-TG) after 12 months. METHODS AND MATERIALS: Seventy-six Class I and II restorations (44 direct and 32 indirect) were inserted in premolars and molars with carious lesions or deficient restorations in 30 healthy patients according to the manufacturer's instructions. Each restoration was evaluated at baseline and after 12 months according to the modified USPHS criteria for color match (CM), marginal discoloration (MD), secondary caries (SC), anatomic form (AF), surface texture (ST), marginal integrity (MI), and pulp sensitivity (PS). Data were analyzed by Fisher and McNemar Chi-square tests. RESULTS: No secondary caries and no pulpal sensitivity were observed after 12 months. However, significant changes in marginal discoloration (MD) criteria could be detected between baseline and one-year results for both materials (p<0.05). For marginal integrity (MI) criteria, the differences between baseline and one-year recall were statistically significant (p<0.05). For marginal integrity (MI) criteria, Tetric Ceram (TC) showed results statistically superior to Targis (TG) in both observation periods (p<0.05). No statistically significant changes in color match (CM), anatomic form (AF), or surface texture (ST) appeared during the observation periods (p>0.05). CONCLUSIONS: BDirect resin composite restorations performed better than indirect composite inlays for marginal integrity, but all restorations were judged to be clinically acceptable. CLINICAL SIGNIFICANCE: Tetric Ceram direct restorations and Targis indirect inlays in posterior teeth provide satisfactory clinical performance and the comparison between them showed little difference after one year.

Simplified occlusal replica adapted technique with glass ionomer cement for molar-incisor hypomineralization-affected molars: An 18-month follow-up.

BACKGROUND AND OVERVIEW: Molar-incisor hypomineralization (MIH) is a qualitative developmental defect of enamel, which has been a daily concern in clinical practice owing to its difficult treatment. CASE DESCRIPTION: An 11-year-old girl was admitted to the pediatric dental clinic with a symptom of severe hypersensitivity in the permanent molars owing to MIH. The treatment consisted of a simplified occlusal replica adapted technique with conventional glass ionomer cement in the MIH-affected molars, which involved laboratory and clinical stages. The patient was reexamined every 3 months, and after 18 months there was no additional tooth structure loss, restoration failure, or pain. This technique may be considered a feasible alternative to restore hypomineralized teeth owing to its reduced procedure time and good performance in the follow-up period of 18 months. CONCLUSIONS AND PRACTICAL IMPLICATIONS: The technique successfully restored the function and shape of the affected teeth, decreasing the sensitivity by means of covering the demarcated MIH opacities.

Molecular Response of Pulp Fibroblasts after Stimulation with Pulp Capping Materials.

This in vitro study evaluated cell viability and metabolism, nitric oxide release and production of two chemokines and one cytokine by cultured human dental pulp fibroblasts (HDPF) in contact with two glass ionomer cements (Ketac Molar-KM and Vitrebond-VB), Single Bond (SB) and calcium hydroxide (Dycal-DY). Cultures of HDPF were established by means of an explant technique. The specimens were prepared under sterile conditions and in disks measuring 5 mm x 2 mm obtained from a prefabricated mold and placed on a permeable membrane to avoid direct contact with the cells. Cytotoxicity was assessed by Trypan Blue exclusion method and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Nitric oxide release in cell supernatant was detected by the Griess Method whereas stromal derived factor-1 alpha (SDF-1α or CXCL12), chemokine (C-X-C motif) ligand 8 [Interleukin 8 (IL-8 or CXCL8)] and interleukin-6 (IL-6) were detected by ELISA. RT-qPCR was employed for gene expression analysis. Statistical analyses were performed by One-way ANOVA followed by Tukey's post hoc test for materials independent of the time, and Two-way ANOVA followed by Bonferroni correction test for the comparisons between materials and experimental time (p<0.05). Cytotoxic tests showed significant differences only for DY. Protein levels and mRNA expression were significantly increased for IL-8 for both periods of time. IL-6 production increased when fibroblasts were stimulated by KM. SDF-1α protein production and mRNA expression were not affected by any of the materials. There was a decrease in nitrate/nitrite levels only for KM. Although DY caused intense cell death and did not stimulate the production of the inflammatory mediators evaluated in this work, it is known that this event seems to be fundamental for the process of repair of the pulp tissue and formation of mineralized barrier. KM and VB increased production of proteins related to the inflammatory process, thus favoring tissue repair. Therefore, although these glass ionomer cements did not lead to large cell death, they should be used with caution.

Correlation between mechanical properties and stabilization time of chemical bonds in glass-ionomer cements.

The objective was to evaluate the compressive strength (CS), diametral tensile strength (DTS), flexural strength (FS), and Knoop microhardness (KH) of different conventional restorative glass-ionomer cements (GICs) and to correlate these mechanical properties (MP) with the stabilization time (ST) of their chemical bonds. Eighteen GICs were tested: Bioglass [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]. The mechanical strength tests were performed in a universal testing machine. KH readings were done with a diamond indenter. STs were examined by Fourier Transform Infrared spectroscopy (FTIR). Data were analyzed with ANOVA and Tukey test (p<0.05). The Spearman rank test was used to evaluate the dependence between the MPs and ST results. The highest MP values were EF, GL2, GL9, GI and KM and the lowest for MG, MA, B, VF and IM. The longest ST was for GL2 and the shortest was for B. ST correlated positively with MP. GICs with longer chemical bonds ST are generally stronger and the ST value obtained from FTIR was useful in predicting the strength of GICs tested.

Mechanical and optical properties of conventional restorative glass-ionomer cements - a systematic review.

OBJECTIVES: To perform a systematic review of test methodologies on conventional restorative glass-ionomer cement (GIC) materials for mechanical and optical properties to compare the results between different GICs. MATERIAL AND METHODS: Screening of titles and abstracts, data extraction, and quality assessments of full-texts were conducted in search for in vitro studies on conventional GICs that follow the relevant specifications of ISO standards regarding the following mechanical and optical properties: compressive strength, flexural strength, color, opacity and radiopacity. SOURCES: The Latin American and Caribbean Health Sciences (LILACS), Brazilian Bibliography of Dentistry (BBO) databases from Latin-American and Caribbean System on Health Sciences Information (BIREME) and PubMed/Medline (US National Library of Medicine - National Institutes of Health) databases were searched regardless of language. Altogether, 1146 in vitro studies were selected. Two reviewers independently selected and assessed the articles according to pre-established inclusion/exclusion criteria. Among all the properties investigated, only one study was classified as being of fair quality that tested compressive strength and was included. It was observed that many authors had not strictly followed ISO recommendations and that, for some properties (diametral tensile strength and microhardness), there are no guidelines provided. CONCLUSIONS: It was not possible to compare the results for the mechanical and optical properties of conventional restorative GICs due to the lack of standardization of studies.

One year clinical evaluation of two different types of composite resins in posterior teeth.

AIM: The aim of this study was to assess the clinical performance of two adhesive restorative systems (Single Bond/Filtek P-60 and Single Bond/Filtek Z-250) in posterior teeth using a modified United States Public Health Service (USPHS) system. METHODS AND MATERIALS: A total of 70 restorations were placed in molars and premolars in 30 patients (14 females and 16 males; 18-40 years) by one operator. All restorations were directly evaluated by two examiners at baseline, six months, and 12 months using the following modified USPHS rating criteria: marginal integrity, marginal discoloration, surface texture, contour, postoperative sensitivity, and recurrent caries. RESULTS: At six and 12 months all restorations were available for evaluation of marginal discoloration, surface texture, contour, postoperative sensitivity, and recurrent caries that remained with 100% Alpha-ratings at recalls for both restorative systems. Marginal integrity for P-60 was scored as 94.3% and 91.4% Alpha at six and 12 months, respectively, and rates for Z-250 were 100% and 97.1% Alpha at six and 12 months, respectively. Statistical analysis was completed with Fisher's exact and McNemar Chi-square tests at a significance level of 5% (P<0.05). CONCLUSION: All restorations were clinically satisfactory and no significant differences were found among them. CLINICAL SIGNIFICANCE: Posterior resin composite restorations placed under appropriate conditions provide a satisfactory clinical performance.

Using UV light for adhesive remnant removal after debonding of orthodontic accessories.

The objective of this study was to assess the effect of a UV light-based auxiliary illumination on adhesive remnant (AR) removal after orthodontic debonding. Sixty human molars were divided according to the adhesive used for bonding: O-opaque; LF-low fluorescence; and HF-high fluorescence. After debonding, the teeth were subdivided according to the AR removal method: No UV light or With UV light. After AR removal, the teeth were polished. Direct visual analysis, scanning electron microscopy (SEM) and time quantification for AR removal analyses were performed (Fisher-Freeman-Halton, Fisher's exact, chi-square trend, ANOVA, and independent t-tests; α = 5%). Concerning the adhesives, there was no significant difference among direct visual, SEM and time analyses for AR removal (p ≥ 0.05). Regarding AR removal methods, a similarity among the subgroups was verified for direct visual and SEM analyses (p≥0.05). However, a significant trend was verified for the with UV light method to produce greater marks, and the no UV light method, to produce a greater rate of samples with AR before polishing (p = 0.015). AR removal with light was significantly quicker in comparison with the no UV light method (p < 0.0001). The use of UV light may aid orthodontists in removing AR more thoroughly and in less time. However, they should receive special training to apply this technology, and should never dismiss the final polishing procedure.

Dental Pulp Fibroblasts Response after Stimulation with HEMA and Adhesive System.

This study evaluated in vitro cell viability and metabolism, nitric oxide release and production of chemokines by cultured human dental pulp fibroblasts (DPF) under contact with HEMA and Single Bond. Cultures of DPF were established by means of an explant technique. Once plated, cells were kept under contact with increasing concentrations of HEMA (10, 100 and 1000 nM) or Single Bond (SB) [10-fold serially diluted in culture medium (10-4, 10-3 and 10-2 v/v)] and also with polymerized SB components. Cytotoxicity was assessed by Trypan Blue exclusion method and MTT [3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. Nitric oxide release on cell supernatant was detected by Griess Method whereas chemokines (CXCL12 and CXCL8) were detected by ELISA. RT-qPCR was employed for chemokines gene expression analysis. Cytotoxic tests showed significant differences for SB 10-2. None of the tested materials significantly altered NO levels. Protein levels of CXCL12 were significantly decreased only by HEMA. On the other hand, while CXCL12 mRNA remained unaltered, gene expression of CXCL8 had significant decrease with all materials, except for polymerized SB. In conclusion, Single Bond and HEMA at various concentrations, decreased expression and production of molecules involved in inflammatory processes and, therefore, the use of adhesive systems such as pulp capping materials must be viewed with caution due to its large cytotoxic effect when in close contact with the pulp.

Randomized clinical trial of encapsulated and hand-mixed glass-ionomer ART restorations: one-year follow-up.

This prospective, randomized, split-mouth clinical trial evaluated the clinical performance of conventional glass ionomer cement (GIC; Riva Self-Cure, SDI), supplied in capsules or in powder/liquid kits and placed in Class I cavities in permanent molars by the Atraumatic Restorative Treatment (ART) approach. A total of 80 restorations were randomly placed in 40 patients aged 11-15 years. Each patient received one restoration with each type of GIC. The restorations were evaluated after periods of 15 days (baseline), 6 months, and 1 year, according to ART criteria. Wilcoxon matched pairs, multivariate logistic regression, and Gehan-Wilcoxon tests were used for statistical analysis. Patients were evaluated after 15 days (n=40), 6 months (n=34), and 1 year (n=29). Encapsulated GICs showed significantly superior clinical performance compared with hand-mixed GICs at baseline (p=0.017), 6 months (p=0.001), and 1 year (p=0.026). For hand-mixed GIC, a statistically significant difference was only observed over the period of baseline to 1 year (p=0.001). Encapsulated GIC presented statistically significant differences for the following periods: 6 months to 1 year (p=0.028) and baseline to 1 year (p=0.002). Encapsulated GIC presented superior cumulative survival rate than hand-mixed GIC over one year. Importantly, both GICs exhibited decreased survival over time. Encapsulated GIC promoted better ART performance, with an annual failure rate of 24%; in contrast, hand-mixed GIC demonstrated a failure rate of 42%.

5-year clinical performance of resin composite versus resin modified glass ionomer restorative system in non-carious cervical lesions.

AIM: To comparatively assess the 5-year clinical performance of a 1-bottle adhesive and resin composite system with a resin-modified glass ionomer restorative in non-carious cervical lesions. METHOD AND MATERIALS: One operator placed 70 restorations (35 resin modified glass ionomer restorations and 35 resin composite restorations) in 30 patients under rubber dam isolation without mechanical preparation. The restorations were directly assessed by 2 independent examiners, using modified USPHS criteria at baseline and 6, 12, 24 and 60 months. RESULTS: Twenty-two patients were available for recall after 5 years (73.3% recall rate) and 55 out of 70 restorations were evaluated. Excellent agreement was registered for all criteria between examiners (kappa > or = 0.85). Sixteen composite restorations were dislodged (51.5% retention) and 1 ionomer restoration was lost (96.4% retention). The McNemar test detected significant differences in resin composite restorations between baseline and 5-year recall for marginal integrity (p<0.001) and retention (p=0.004). For resin modified glass ionomer restorations, no significant differences were identified for all criteria (p>0.05). When comparing both materials, the Fisher exact test pointed out significant differences in retention (p=0.002) after 5 years of clinical service. CONCLUSIONS: After 5 years of evaluation, the clinical performance of resin modified glass ionomer restorations was superior to resin composite restorations.

Dental caries spectrum profile in Brazilian public school children and adolescents

Abstract Dental caries remains a major public health problem, with a higher prevalence among in adolescence. The present study aimed to assess the dental caries spectrum profile in children and adolescents in Brazilian public schools. A cross-sectional study was performed in two public schools in Brazil to examine the permanent teeth of children and adolescents. The dental caries were assessed by applying the Caries Assessment Spectrum and Treatment (CAST) instrument, and the results were distributed as per disease status (healthy/codes 0-2; pre-morbidity/code 3; morbidity/code 4-5; severe morbidity/codes 6-7; mortality/code 8) and by severity as per the CAST-F1 formula (no severity, mild, moderate, and severe). The CAST data were described by age groups (8-9 y, 10-11 y, 12-13 y, 14-15 y, 16-17 y, and 18-19 y). The Kruskal-Wallis test was used to investigate differences in CAST prevalence and severity among the groups (p < 0.05). Total 598 students were enrolled. Most of the subjects were male (53.34%) and belonged to the age group of 12-13 y (34.95%). The variables CAST 0/1 (p = 0.024), CAST (p = 0.024), and CAST-F1 (p = 0.029) showed significant differences among age groups, and the post hoc test showed the differences in these variables as per the age groups of 14-15 y and 16-17 y (CAST 0/1, p = 0.047; CAST, p = 0.047; CAST-F1, p = 0.033). The dental caries spectrum increased from 8 to 19 y with a peak in the prevalence and severity in the middle of adolescence.

A prospective and randomized clinical trial evaluating the effectiveness of ART restorations with high-viscosity glass-ionomer cement versus conventional restorations with resin composite in Class II cavities of permanent teeth: two-year follow-up

Abstract Objective To compare the effectiveness of ART restorations using High Viscosity Glass-ionomer cement (HVGIC) with conventional restorations using resin composite in Class II cavities of permanent teeth, in a 2-year follow-up. Methodology Seventy-seven restorations were made with each restorative material, Equia Fil-GC Corporation (ART restorations) and Z350-3M (conventional restoration), in 54 participants in this parallel and randomized clinical trial. Restorations were evaluated at 6 months, 1 and 2 years using the ART and the modified United States Public Health Service (USPHS) criteria. Chi-square test and Survival Analysis (p<0.05) were used for statistical analysis. Results The success rates for ART restorations were 98.7% (6 months) and 95.8% (1 year) for both criteria. At 2 years, success rate was 92% and 90.3% when scored by the modified USPHS and ART criteria (p=0.466), respectively. The success rates for conventional restorations were 100% (6 months), 98.7% (1 year) and 91.5% (2 years) for both assessment criteria. ART restorations presented a lower survival rate by the criterion of ART (83.7%) when compared to the modified USPHS criterion of (87.8%), after 2 years (p=0.051). The survival of conventional restorations was 90.7% for both evaluation criteria. Conclusion At the 2-years follow-up evaluation, no statistically significant difference was observed between the success rate of ART restorations with HVGIC compared to conventional restorations with resin composite in Class II cavities of permanent teeth.

Effect of different finishing and polishing techniques on the surface roughness of microfilled, hybrid and packable composite resins.

This study examined the average surface roughness (Ra, microm) of 2 microfilled (Durafill and Perfection), 1 hybrid (Filtek Z250) and 2 packable composite resins (Surefil and Fill Magic), before (baseline) and after eight different finishing and polishing treatments. The surface roughness was assessed using a profilometer. Ten specimens of each composite resin were randomly subjected to one of the following finishing/polishing techniques: A -- carbide burs; B -- fine/extrafine diamond burs; C -- Sof-Lex aluminum oxide discs; D -- Super-Snap aluminum oxide discs; E -- rubber polishing points + fine/extrafine polishing pastes; F -- diamond burs + rubber polishing points + fine/extrafine polishing pastes; G -- diamond burs + Sof-Lex system; H -- diamond burs + Super-Snap system. Data were analyzed using two-way ANOVA and Tukey's HSD test. Significant differences (p<0.05) were detected among both the resins and the finishing/polishing techniques. For all resins, the use of diamond burs resulted in the greatest surface roughness (Ra: 0.69 to 1.44 microm). The lowest Ra means were obtained for the specimens treated with Sof-Lex discs (Ra: 0.11 to 0.25 microm). The Ra values of Durafill were lower than those of Perfection and Filtek Z250, and these in turn had lower Ra than the packable composite resins. Overall, the smoothest surfaces were obtained with the use the complete sequence of Sof-Lex discs. In areas that could not be reached by the aluminum oxide discs, the carbide burs and the association between rubber points and polishing pastes produced satisfactory surface smoothness for the packable and hybrid composite resins, respectively.

Microhardness of resin-based materials polymerized with LED and halogen curing units.

The purpose of this study was to evaluate the microhardness of resin-based materials polymerized with a LED (light-emitting diode) light-curing unit (LCU) and a halogen LCU. Twenty cylindrical specimens (3.0 mm in diameter and 2.0 mm high) were prepared for each tested material (Z100, Definite and Dyract). Specimens were light-cured with two LCUs (Ultraled and Curing Light 2500) for either 40 or 60 s on their top surfaces. Hardness was measured on top and bottom surfaces of each specimen. Statistical analysis was done by ANOVA and Tukey's test (p<0.05). There was no significant difference in hardness between LED LCU and halogen LCU for Z100 and Dyract on top surface. Conversely, lower hardness was recorded when Definite was light-cured with the LED LCU than with the halogen lamp. On bottom surface, hardness was significantly lower for all materials light-cured with LED LCU. Z100 was harder than Dyract and Definite regardless of the light curing unit. There was no significant difference in hardness between the exposure times on top surface. Higher hardness was obtained when the materials were light-cured for 60 s on bottom surface. The tested LED was not able to produce the same microhardness of resin-based materials as the halogen LCU.

Effect of resin-modified glass-ionomer cement lining and composite layering technique on the adhesive interface of lateral wall.

UNLABELLED: Interface integrity can be maintained by setting the composite in a layering technique and using liners. OBJECTIVE: The aim of this in vitro study was to verify the effect of resin-modified glass-ionomer cement (RMGIC) lining and composite layering technique on the bond strength of the dentin/resin adhesive interface of lateral walls of occlusal restorations. MATERIAL AND METHODS: Occlusal cavities were prepared in 52 extracted sound human molars, randomly assigned into 4 groups: Group 2H (control) - no lining + two horizontal layers; Group 4O: no lining + four oblique layers; Group V-2H: RMGIC lining (Vitrebond) + two horizontal layers; and Group V-4O: RMGIC lining (Vitrebond) + four oblique layers. Resin composite (Filtek Z250, 3M ESPE) was placed after application of an adhesive system (Adper™ Single Bond 2, 3M ESPE) dyed with a fluorescent reagent (Rhodamine B) to allow confocal microscopy analysis. The teeth were stored in deionized water at 37oC for 24 hours before being sectioned into 0.8 mm slices. One slice of each tooth was randomly selected for Confocal Laser Scanning Microscopy (CLSM) analysis. The other slices were sectioned into 0.8 mm x 0.8 mm sticks to microtensile bond strength test (MPa). Data were analyzed by two-way ANOVA and Fisher's test. Results There was no statistical difference on bond strength among groups (p>0.05). CLSM analysis showed no significant statistical difference regarding the presence of gap at the interface dentin/resin among groups. CONCLUSIONS: RMGIC lining and composite layering techniques showed no effect on the microtensile bond strength and gap formation at the adhesive interface of lateral walls of high C-factor occlusal restorations.

Molecular response of pulp fibroblasts after stimulation with pulp capping materials

Abstract This in vitro study evaluated cell viability and metabolism, nitric oxide release and production of two chemokines and one cytokine by cultured human dental pulp fibroblasts (HDPF) in contact with two glass ionomer cements (Ketac Molar-KM and Vitrebond-VB), Single Bond (SB) and calcium hydroxide (Dycal-DY). Cultures of HDPF were established by means of an explant technique. The specimens were prepared under sterile conditions and in disks measuring 5 mm x 2 mm obtained from a prefabricated mold and placed on a permeable membrane to avoid direct contact with the cells. Cytotoxicity was assessed by Trypan Blue exclusion method and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Nitric oxide release in cell supernatant was detected by the Griess Method whereas stromal derived factor-1 alpha (SDF-1α or CXCL12), chemokine (C-X-C motif) ligand 8 [Interleukin 8 (IL-8 or CXCL8)] and interleukin-6 (IL-6) were detected by ELISA. RT-qPCR was employed for gene expression analysis. Statistical analyses were performed by One-way ANOVA followed by Tukey's post hoc test for materials independent of the time, and Two-way ANOVA followed by Bonferroni correction test for the comparisons between materials and experimental time (p<0.05). Cytotoxic tests showed significant differences only for DY. Protein levels and mRNA expression were significantly increased for IL-8 for both periods of time. IL-6 production increased when fibroblasts were stimulated by KM. SDF-1α protein production and mRNA expression were not affected by any of the materials. There was a decrease in nitrate/nitrite levels only for KM. Although DY caused intense cell death and did not stimulate the production of the inflammatory mediators evaluated in this work, it is known that this event seems to be fundamental for the process of repair of the pulp tissue and formation of mineralized barrier. KM and VB increased production of proteins related to the inflammatory process, thus favoring tissue repair. Therefore, although these glass ionomer cements did not lead to large cell death, they should be used with caution.

Resumo Este estudo avalia in vitro a viabilidade e metabolismo celular, a liberação de óxido nítrico e a produção de duas quimiocinas e uma citocina por fibroblastos de polpa dentária humana em cultura (FPDH) em contato com dois cimentos de ionômero de vidro (Ketac Molar-KM e Vitrebond-VB), Single Bond (SB) e hidróxido de cálcio (Dycal-DY). As culturas de FPDH foram estabelecidas por meio de uma técnica de explante. As amostras foram preparadas em condições estéreis e em discos de 5 mm x 2 mm, obtidas de um molde pré-fabricado e colocadas em uma membrana permeável (Maxicell 24 W 0,4 µm) para evitar o contato direto com as células. A citotoxicidade foi avaliada pelo método de exclusão de Trypan Blue e pelo ensaio de MTT. A liberação de óxido nítrico no sobrenadante celular foi detectada pelo método Griess, enquanto fator 1 derivado do estroma (SDF-1α ou CXCL12), interleucina-8 (IL-8 ou CXCL8) and interleucina-6 (IL-6) foram detectados por ELISA. RT-qPCR foi empregada para análise de expressão gênica. As análises estatísticas foram realizadas por ANOVA a 1 critério, seguida pelo pós-teste de Tukey para os materiais independentes do tempo, e ANOVA a 2 critérios, seguida pelo teste de correção de Bonferroni para comparações entre materiais e tempo experimental (p<0,05). Os testes citotóxicos mostraram diferenças significativas apenas para DY. Os níveis da proteína e a expressão de RNAm para IL-8 aumentaram significativamente para ambos os tempos estudados. A produção de IL-6 aumentou quando os fibroblastos foram estimulados por KM. A produção da proteína e a expressão de RNAm para SDF-1α não foram afetadas por nenhum dos materiais. Houve uma diminuição nos níveis de nitrato/nitrito apenas para KM. Embora o DY tenha causado intensa morte celular e não tenha estimulado a produção dos mediadores inflamatórios avaliados neste trabalho, sabe-se que esse evento parece ser fundamental para o processo de reparo do tecido pulpar e formação de barreira mineralizada. Os cimentos de ionômero de vidro utilizados aumentaram a produção de proteínas relacionadas ao processo inflamatório, favorecendo a reparação tecidual e, portanto, esses materiais, embora não causem grande morte celular, devem ser utilizados com cautela.

Correlation between mechanical properties and stabilization time of chemical bonds in glass-ionomer cements

Abstract The objective was to evaluate the compressive strength (CS), diametral tensile strength (DTS), flexural strength (FS), and Knoop microhardness (KH) of different conventional restorative glass-ionomer cements (GICs) and to correlate these mechanical properties (MP) with the stabilization time (ST) of their chemical bonds. Eighteen GICs were tested: Bioglass [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]. The mechanical strength tests were performed in a universal testing machine. KH readings were done with a diamond indenter. STs were examined by Fourier Transform Infrared spectroscopy (FTIR). Data were analyzed with ANOVA and Tukey test (p<0.05). The Spearman rank test was used to evaluate the dependence between the MPs and ST results. The highest MP values were EF, GL2, GL9, GI and KM and the lowest for MG, MA, B, VF and IM. The longest ST was for GL2 and the shortest was for B. ST correlated positively with MP. GICs with longer chemical bonds ST are generally stronger and the ST value obtained from FTIR was useful in predicting the strength of GICs tested.