Gisele F. Neiva

Polymerization shrinkage and depth of cure of bulk fill flowable composite resins.

OBJECTIVE To evaluate polymerization shrinkage and depth of cure of two bulk fill flowable composites, one nanohybrid composite modified to a flowable consistency, and one standard flowable composite, comparing the scraping method to the Knoop hardness test. METHODS Two bulk fill flowable composites, SureFil SDR flow (SSF) (Dentsply) and Venus Bulk Fill (VBF) (Heraeus Kulzer), one standard flowable, Filtek Supreme Ultra Flowable (FSUF) (3M/ESPE) (control), and one regular bulk composite that can be made flowable, SonicFill (SF) (Kerr), were used in this study. For polymerization shrinkage (PS), ten 2-mm samples were made for each composite and cured for 20 seconds and shrinkage was measured with a Kaman linometer. For hardness, ten specimens of each composite were made in a 10 × 10-mm mold and cured for 20 seconds; the bottom surface was scraped according to ISO 4049 specification, and the remaining thickness was measured with a micrometer. Hardness samples were prepared at 2-, 3-, 4-, and 5-mm thick ×14-mm diameter, cured for 20 seconds, and polished. After 24 hours of dry storage, a Knoop indenter was applied at 100 g load for 11 seconds. Three readings were made on the top and bottom of each specimen and averaged for each surface to calculate a Knoop hardness value and a bottom/top hardness ratio. One-way analysis of variance and Tukey tests were used to determine significant differences between thicknesses and between test methods for each material. RESULTS PS values were 3.43 ± 0.51%, 3.57 ± 0.63%, 4.4 ± 0.79%, and 1.76 ± 0.53% for FSUF, SSF, VBF, and SF, respectively. VBF showed significantly greater shrinkage (4.4 ± 0.79%), followed by FSUF (3.43 ± 0.51%) and SSF (3.57 ± 0.63%), which were similar, and SF (1.76 ± 0.53%), which had significantly less shrinkage (p<0.05). Values for the scraping method for depth of cure were significantly greater for SSF and VBF (>5.0 mm), followed by SF (3.46 ± 0.16 mm) and FSU (2.98 ± 0.22 mm). Knoop top hardness values (KHN) were: VBF 21.55 ± 2.39, FSUF 44.62 ± 1.93, SSF 29.17 ± 0.76, and SF 72.56 ± 2.4 at 2 mm and were not significantly different at 3-, 4-, and 5-mm thick within each material. Ratios for bottom/top values (depth of cure) for 2, 3, 4, and 5 mm were: VBF 0.80 ± 0.1, 0.78 ± 0.03, 0.67 ± 0.10, and 0.59 ± 0.07, respectively; SSF 0.74 ± 0.08, 0.72 ± 0.08, 0.69 ± 0.18, and 0.62 ± 0.08, respectively; SF 0.82 ± 0.05, 0.68 ± 0.05, 0.47 ± 0.04, and 0.21 ± 0.02, respectively; and FSUF 0.56 ± 0.08 at 2 mm and 0.40 ± 0.08 at 3 mm. The bottom/top ratio was .80 or less at all depths and decreased below 0.70 at 4-mm depth for VBF and SSF, at 3 mm for SF and at 2 mm for FSUF.

Marginal Adaptation and Color Stability of Four Provisional Materials

PURPOSE A number of provisional restorative materials exist on the market. This study tested marginal fit and color stability of three provisional restorative materials and a control. MATERIALS AND METHODS Two auto-cure materials, Protemp Garant and Integrity, and one dual-cure material, Luxatemp Solar, were tested against SNAP, a polyethyl methacrylate control. A maxillary right central incisor ivorine tooth was prepared for a full coverage all-ceramic crown, with a 1.5-mm chamfer margin. Four points were engraved at a point 1 mm below the facial, lingual, mesial, and distal margins, and replicas (n = 40) were produced by the manufacturer. Provisional crowns (n = 10 x 4) were fabricated on the individual replicas using a polyethylene coping template. The crowns were trimmed under magnification using an acrylic bur. The distance from the crown margins to a point tangent to the engraved markings was measured under 10x magnification and recorded. For color stability, 10-mm diameter x 2-mm thick discs (n = 10 x 4) were fabricated and immersed cyclically in tea for 1 week in a Tucillo/Nielson apparatus. Color measurements were recorded for each specimen at baseline and after staining. DeltaE values were calculated to determine the extent of the color change. RESULTS The means of the four marginal discrepancy measurements for each specimen were analyzed using a 1-way ANOVA and Tukey post-hoc comparison. Luxatemp Solar had statistically significant marginal discrepancy (319 microm, p < 0.05) when compared to the other provisional materials. A significant color change (DeltaE = 4.33, p < 0.05) was found for Protemp Garant. CONCLUSION The dual-cure temporary material (Luxatemp Solar) exhibited significantly more discrepancy at the margin than the auto-cure bis-acryl materials or acrylic control. Protemp Garant exhibited a clinically noticeable change in shade after 1 week in staining solution, whereas the other materials did not exhibit a clinically noticeable change. CLINICAL IMPLICATIONS Provisional crowns fabricated from SNAP, Protemp Garant, and Integrity exhibited similarly low marginal discrepancy. SNAP, Luxatemp Solar, and Integrity did not demonstrate a clinically detectable change in shade after 1 week in a staining solution.

Hard and Soft Tissue Changes After Crestal and Subcrestal Immediate Implant Placement

BACKGROUND The purpose of this study is to assess the influence of the placement level of implants with a laser-microtextured collar design on the outcomes of crestal bone and soft tissue levels. In addition, we assessed the vertical and horizontal defect fill and identified factors that influenced clinical outcomes of immediate implant placement. METHODS Twenty-four patients, each with a hopeless tooth (anterior or premolar region), were recruited to receive dental implants. Patients were randomly assigned to have the implant placed at the palatal crest or 1 mm subcrestally. Clinical parameters including the keratinized gingival (KG) width, KG thickness, horizontal defect depth (HDD), facial and interproximal marginal bone levels (MBLs), facial threads exposed, tissue-implant horizontal distance, gingival index (GI), and plaque index (PI) were assessed at baseline and 4 months after surgery. In addition, soft tissue profile measurements including the papilla index, papilla height (PH), and gingival level (GL) were assessed after crown placement at 6 and 12 months post-surgery. RESULTS The overall 4-month implant success rate was 95.8% (one implant failed). A total of 20 of 24 patients completed the study. At baseline, there were no significant differences between crestal and subcrestal groups in all clinical parameters except for the facial MBL (P = 0.035). At 4 months, the subcrestal group had significantly more tissue thickness gain (keratinized tissue) than the crestal group compared to baseline. Other clinical parameters (papilla index, PH, GL, PI, and GI) showed no significant differences between groups at any time. A facial plate thickness ≤1.5 mm and HDD ≥2 mm were strongly correlated with the facial marginal bone loss. A facial plate thickness ≤2 mm and HDD ≥3 were strongly correlated with horizontal dimensional changes. CONCLUSIONS The use of immediate implants was a predictable surgical approach (96% survival rate), and the level of placement did not influence horizontal and vertical bone and soft tissue changes. This study suggests that a thick facial plate, small gaps, and premolar sites were more favorable for successful implant clinical outcomes in immediate implant placement.

Surface Evaluation of Polishing Techniques for New Resilient CAD/CAM Restorative Materials

PURPOSE The purpose of this study was to measure the surface roughness of milled chairside computer-assisted design/computer assisted machining (CAD/CAM) restorations using several contouring/polishing systems as to their effectiveness for creating a clinically acceptable surface. MATERIALS AND METHODS One hundred onlays were milled from monolithic CAD/CAM blocks with an MCXL milling chamber (Sirona Dental) as follows: 30 resin nano-ceramic (Lava Ultimate, 3M ESPE), 30 hybrid ceramic (Enamic, Vita) and 40 leucite-reinforced ceramic (EmpressCAD, Ivoclar). A single group of EmpressCAD onlays was glazed-fired in a porcelain oven (Programat CS2, Ivoclar). Finishing and polishing systems consisted of either an abrasive-polish technique or a brush-polish technique. Roughness values were measured using a three-dimensional measuring laser microscope (OLS4000 LEXT by Olympus). RESULTS There was a significant difference in the baseline surface roughness of the CAD/CAM materials (p ≤ 0.05), with the resin nano-ceramic (Lava Ultimate) being smoother than the hybrid ceramic (Enamic), and both being smoother than the leucite-reinforced ceramic (EmpressCAD). All polishing techniques resulted in a smoother surface compared with the baseline surface for the leucite-reinforced ceramic (p ≤ 0.05), with both techniques resulting in a significantly smoother surface than glazing in a porcelain oven (p ≤ 0.05). Both polishing techniques resulted in a smoother surface compared with the baseline surface for both the nano-ceramic and hybrid ceramic materials (p ≤ 0.05). CONCLUSIONS It is possible to create an equally smooth surface for chairside CAD/CAM resilient materials compared with milled ceramics using several finishing and polishing techniques. In general, the polished ceramic surfaces were smoother than the glazed ceramic surfaces. CLINICAL SIGNIFICANCE The results of the study indicate that it is possible to create an equally smooth surface for chairside CAD/CAM resilient materials compared with milled ceramics using several finishing and polishing techniques. In addition, both polishing techniques resulted in smoother ceramic surfaces when compared to glazed ceramic surfaces. The polished surface of the ceramic material was smoother than the glazed ceramic surface.

In Vitro Evaluation of Tooth-color Change Using Four Paint-on Tooth Whiteners

The effectiveness of four paint-on tooth whiteners was evaluated and compared in this in vitro study. Sixty extracted anterior teeth were selected and randomly assigned to five groups: 1-(AS) Artificial Saliva (Roxane); 2-(MSW) Sparkling White (Meijer); 3-(CNE) Crest Night Effects (Procter & Gamble); 4-(ABB) Beautifully Bright (Avon) and 5-(CSWN) Simply White Night Gel (Colgate-Palmolive). The teeth were cleaned with a soft bristle toothbrush and toothpaste (Procter & Gamble) to remove any residue from the storage solution. The bleaching gels were painted onto the surface of the teeth, and they were then wrapped in gauze moistened with artificial saliva and kept in 100% humidity at 98 degrees F in a laboratory oven (Precision Scientific model 18EG) for 24 hours. The treatment was repeated once a day for 14 days. Visual color assessment was done using a value-oriented Vitapan Classical Shade Guide (Vident) and a colorimeter (Minolta Chroma Meter CR 321). PVS jigs (Exaflex, GC America) were fabricated for each tooth. Visual and colorimetric readings were recorded at baseline, 7 and 14 days. One-way ANOVA and Tukey multiple comparisons test were used to assess differences between groups. CNE and CSWN presented the highest mean number of shade changes and deltaE*ab Colorimeter readings. ABB and MSW did not significantly lighten the teeth, as measured by either method of evaluation after two weeks of the bleaching regimen.

Estimation of clinical axial extension of Class II caries lesions with ultraspeed and digital radiographs: An in-vivo study

This study compared the newly introduced direct digital radiographic (DDR) system (RVG-6000) with conventional bitewing radiographs (D-speed film) to estimate the extension of Class II caries lesions. The patients discomfort related to placement of each radiographic packet was also evaluated. Fifty-one Class II caries lesions were selected. Affected teeth were radiographed with D-speed film and t he RVG-6000 size 2sensor. Patients were asked to complete a one-page questionnaire regarding discomfort during the radiographic examination. The true caries depth was validated clinically from intra-operative photographs that captured the cross-sectional views of the lesion at its deepest point. During the operative procedures, the cavitation status was also recorded. A reference device was placed on the occlusal surface of the treatment or the adjacent tooth before taking radiographs and during the operative procedure. The caries lesion extension from the dentino-enamel junction (DEJ) was measured in mm on eachradiograph and the results were compared to the true clinical depth. Both radiographs significantly underestimated the clinical depth (p < 0.0001), but the RVG-6000 images were significantly closer to the actual depth of the lesion than the D-speed film (p = 0.0031). All of the lesions which were diagnosed radiographically to be deeper than 1 mm into dentin were cavitated. Size, sharp edges of the sensor or both comprised the source(s) of most of the discomfort caused by D-speed film (64%) and RVG-6000 sensor (79%). The results of this study showed that both types of radiographic images tend to underestimate caries depth; however, the RVG-6000 image was more accurate than the D-speed film. This study also provides information about sources of the patients discomfort associated with these radiographs.

Polymerization Shrinkage and Depth of Cure of Bulk Fill Flowable Composite Resins: COMMENTARY

The Journal of Esthetic and Restorative Dentistry published a Critical Appraisal of bulk-fill flowable composite resins by Dr. Ricardo Walter in early 2013 (JERD 2013;25(1):72–6). Since then, new bulk-fill composite options have become available and have rapidly achieved great popularity. This two-part Critical Appraisal reviews some of the more recent information on the various bulk-fill options.

Influence of Different CAM Strategies on the Fit of Partial Crown Restorations: A Digital Three-dimensional Evaluation

OBJECTIVE CAM fabrication is an important step within the CAD/CAM process. The internal fit of restorations is influenced by the accuracy of the subtractive CAM procedure. Little is known about how CAM strategies might influence the fit of CAD/CAM fabricated restorations. The aim of this study was to three-dimensionally evaluate the fit of CAD/CAM fabricated zirconia-reinforced lithium silicate ceramic partial crowns fabricated with three different CAM strategies. The null hypothesis was that different CAM strategies did not influence the fitting accuracy of CAD/CAM fabricated zirconia-reinforced lithium silicate ceramic partial crowns. METHODS AND MATERIALS Preparation for a partial crown was performed on a maxillary right first molar on a typodont. A chairside CAD/CAM system with the intraoral scanning device CEREC Omnicam (Dentsply Sirona, York, PA, USA) and the 3+1 axis milling unit CEREC MCXL was used. There were three groups with different CAM strategies: step bur 12 (12), step bur 12S (12S), and two step-mode (12TWO). The zirconia-reinforced lithium silicate ceramic Celtra Duo (Dentsply Sirona) was used as the CAD/CAM material. A new 3D method for evaluating the fit was applied, consisting of the quadrant scan with the intraoral scanning device CEREC Omnicam. The scan of the PVS material adherent to the preparation and the preparation scan were matched, and the difference analysis was performed with special software OraCheck (Cyfex AG, Zurich, Switzerland). Three areas were selected for analysis: margin (MA), axial (AX), and occlusal (OC). Statistical analysis was performed using 80% percentile, one-way ANOVA, and the post hoc Scheffé test with α=0.05. RESULTS Statistically significant differences were found both within and between the test groups. The aspect axial fit results varied from 90.5 ± 20.1 μm for the two-step milling mode (12TWO_AX) to 122.8 ± 12.2 μm for the milling with step bur 12S (12S_AX). The worst result in all groups was found for the aspect occlusal fit with the highest value for group 12S of 222.8 ± 35.6 μm. Group two-step milling mode (12TWO) performed statistically significantly better from groups 12 and 12S for the occlusal fit ( p<0.05). Deviation patterns were visually analyzed with a color-coded scheme for each restoration. CONCLUSIONS CAM strategy influenced the internal adaptation of zirconia-reinforced lithium silicate partial crowns fabricated with a chairside CAD/CAM system. Sensible selection of specific areas of internal adaptation and fit is an important factor for evaluating the CAM accuracy of CAD/CAM systems.

Three-Dimensional Digital Evaluation of the Fit of Endocrowns Fabricated from Different CAD/CAM Materials: Fitchecker CAD/CAM Materials

PURPOSE A wide variety of CAD/CAM materials are available for single-tooth restorations. CAD/CAM material characteristics are different and may influence CAM fabrication accuracy. There is no study investigating the influence of different CAD/CAM materials on the final fit of the restoration. The aim of this study was to evaluate the fit of endocrowns fabricated from different CAD/CAM materials using a new 3D evaluation method with an intraoral scanning system. The null hypothesis was that there are no significant differences for the fitting accuracy of different CAD/CAM materials. MATERIALS AND METHODS Preparation for an endocrown was performed on a maxillary right first molar on a typodont, and restorations were fabricated with a chairside CAD/CAM system (CEREC Omnicam, MCXL). Three groups using three different CAD/CAM materials were established (each n = 10): zirconia-reinforced lithium silicate ceramic (Celtra Duo; CD), leucite-reinforced silicate ceramic (Empress CAD; EM), resin nanoceramic (Lava Ultimate; LU). A 3D digital measurement technique (OraCheck, Cyfex AG) using an intraoral scanner (CEREC Omnicam) was used to measure the difference in fit between the three materials for a master endocrown preparation. The preparation scan and the endocrown fit scan were matched with special difference analysis software OraCheck. Three areas were selected for fitting accuracy measurements: margin (MA), axial (AX), occlusal (OC). Statistical analysis was performed using 80% percentile, one-way ANOVA, and post-hoc Scheffé test. Significance level was set to p = 0.05. RESULTS Results varied from best 88.9 ± 7.7 μm for marginal fit of resin nanoceramic restorations (LU_MA) to worst 182.3 ± 24.0 μm for occlusal fit of zirconia-reinforced lithium silicate restorations (CD_OC). Statistically significant differences were found both within and among the test groups. Group CD performed statistically significantly different from group LU for marginal fit (MA) and axial fit (AX) (p < 0.05). For occlusal fit (OC), no statistically significant differences were found within all three test groups (p > 0.05). Deviation pattern for differences was visually analyzed with a color-coded scheme for each restoration. CONCLUSIONS Statistically significant differences were found for different CAD/CAM materials if the CAM procedure was identical. Within the limitations of this study, the choice of CAD/CAM material may influence the fitting accuracy of CAD/CAM-fabricated restorations.

Fluoride Levels in Unstimulated Whole Saliva following Clinical Application of Different 5% NaF Varnishes

The aim of this study was to evaluate the fluoride release from differently formulated 5% NaF varnishes into unstimulated whole saliva in vivo. The fluoride concentration in unstimulated whole saliva was determined after the application of 3 different 5% NaF varnishes (5% NaF, 5% NaF + tricalcium phosphate [TCP], and 5% NaF + amorphous calcium phosphate [ACP]) or a placebo. Fifteen subjects were recruited and enrolled following Institutional Review Board approval based upon the inclusion/exclusion criteria of this study. A cross-over study design was used for the application of either one of the 5% NaF varnishes or a placebo. Unstimulated whole saliva was collected at baseline and at 1, 4, 6, 26, and 50 h following application and analyzed for supernatant ionic fluoride and whole fluoride by microdiffusion. Linear mixed-effects models (5% significance level) were used to determine the effects of varnish and time on the salivary fluoride concentration. The highest amount of fluoride in saliva was found 1 h after application of the fluoride varnishes, with no significant differences among the treatment varnishes with respect to whole fluoride but with lower levels for 5% NaF + ACP in the saliva supernatant. Salivary fluoride levels at 4, 6, and 26 h decreased at each time point and were generally significantly higher for 5% NaF and 5% NaF + TCP. After 50 h, fluoride levels in saliva for all groups were at or below baseline levels. In conclusion, the formulation of other ingredients in fluoride varnishes can affect the fluoride concentration in saliva. The reasons for this phenomenon warrant further investigation since it might affect efficacy of the treatment. This trial is registered at ClinicalTrials.gov (NCT01629290).