Surface smoothness of resin composites after polishing-A systematic review and network meta-analysis of in vitro studies.

A systematic review and network meta-analysis was performed to provide evidence for the best polishing protocol for different types of resin composites to minimize surface roughness. A search was performed in PubMed, Scopus, Web of Science, LILACS, BBO, EMBASE, and Cochrane Library on July 2, 2019 (updated in December, 2020). In vitro studies that included at least two systems for polishing resin composites and analyzed surface roughness were included. The risk of bias was evaluated. A random-effects Bayesian-mixed treatment comparison model was used to compare surface roughness in resin composites with the different types of polishers. Surface under the cumulative ranking curve (SUCRA) analysis was performed to rank the probability for the best polishing system. After removal of duplicates, title and abstract screening yielded 34 studies. Network meta-analysis was not possible for hybrid and microhybrid composites. SUCRA analysis showed that abrasive paper discs allowed greater surface smoothness for nanohybrid and nanofill composites to a probability of between 83% and 91.6%. Silicon carbide brush had a 78.2% probability of being the best system for microfill composites. The use of abrasive paper disc polishers showed a favorable result in nanofill and nanohybrid resin composites. Silicon carbide brush has a greater chance of promoting a smoother surface for microfill resin composites.

Effect of Two Polishing Systems on Surface Roughness, Topography, and Flexural Strength of a Monolithic Lithium Disilicate Ceramic.

PURPOSE: To evaluate the effect of overglazing and two polishing procedures on flexural strength and quality and quantity of surface roughness of a monolithic lithium disilicate ceramic computer-aided design (CAD) after grinding. MATERIALS AND METHODS: This in vitro study was conducted on 52 partially crystalized bar-shaped specimens (16 × 4 × 1.6 mm) of monolithic lithium disilicate ceramic. The specimens were wet polished with 600-, 800-, and 1200-grit silicon carbide papers for 15 seconds using a grinding/polishing machine at a speed of 300 rpm. Then, the specimens were crystalized and glaze-fired in one step simultaneously and randomly divided into four groups of 13: (I) Glazing group (control); (II) Grinding-glazing group, subjected to grinding with red band finishing diamond bur (46 µm) followed by glazing; (III) Grinding-D+Z group, subjected to grinding and then polishing by coarse, medium, and fine diamond rubber points (D+Z); and (IV) Grinding-OptraFine group, subjected to grinding and then polishing with a two-step diamond rubber polishing system followed by a final polishing step with an OptraFine HP brush and diamond polishing paste. The surface roughness (Ra and Rz) values (µm) were measured by a profilometer, and the mean values were compared using one-way ANOVA and Tamhane's test (post hoc comparison). One specimen of each group was evaluated under a scanning electron microscope (SEM) for surface topography. The three-point flexural strength values of the bars were measured using a universal testing machine at a 0.5 mm/min crosshead speed and recorded. The data were analyzed using one-way ANOVA and Tamhane's test (α = 0.05). RESULTS: Statistically significant differences were noted among the experimental groups for Ra, Rz (p < 0.0001), and flexural strength values (p < 0.009). The lowest Ra and Rz values were found in the grinding-OptraFine group (0.465 ± 0.153), which were significantly lower than those in glazing (p < 0.03) and grinding-glazing (p < 0.001) groups. The Ra and Rz values were not significantly different between the two polishing systems (p = 0.23 and p = 0.25, respectively). The highest flexural strength was found in the glazing group (283.350 ± 49.854 MPa) without significant differences compared to grinding-glazing (p = 0.98) and grinding-OptraFine groups (p = 0.86). The lowest flexural strength was found in grinding-D+Z group (225.070 ± 17.299), which was significantly different from the value in glazing (p < 0.03) and grinding-glazing (p < 0.04) groups. SEM analysis of polished surfaces revealed regular morphology with some striations. CONCLUSIONS: The OptraFine system created smoother and more uniform surfaces in terms of quantity (p < 0.03 for Ra, p < 0.01 for Rz) and quality of roughness compared to glazing. The flexural strength of lithium disilicate ceramic after polishing with the OptraFine system was similar to that after glazing (p = 0.86). Despite similar surface roughness after polishing with the two systems, the D+Z system reduced the flexural strength of ceramic (p < 0.03).

A Study on Topographical Properties and Surface Wettability of Monolithic Zirconia after Use of Diverse Polishing Instruments with Different Surface Coatings.

PURPOSE: To investigate the surface topography parameters and wettability of monolithic zirconia (MZ) using polishing instruments with different coatings. MATERIALS AND METHODS: MZ specimens (N = 50, n = 10 per group) (12 × 12 × 1.8 mm3 ) were highly polished. Five polishing systems were studied: BG: silicon carbide polishers; CG: diamond-impregnated ceramic polisher kit; EV: synthetically bonded grinder interspersed with diamond; SL: urethane-coated paper with aluminum oxide grits; and DB: diamond bur (8 µm). Specimens were initially roughened with 220 µm grit diamond burs (10 seconds, 160,000 rpm). After baseline measurements, they were further polished for 10 seconds using a slow-speed handpiece under water coolant, except for SL using a custom-made device (7.5 N), with speed ranging between 5000 and 30,000 rpm. Topographical changes were evaluated considering (a) weight (digital scale), (b) volume loss (digital microscope), (c) vertical height loss (digital microscope), (d) surface roughness (Ra) (profilometer), and (e) surface wettability (goniometer, water). RESULTS: Compared to baseline, material loss from the surface after polishing (ΔW) ranged between 0.00 ± 0.0001×10-1 and -0.03 ± 0.008×10-1 g (SLa < CGa < BGa < DBb < EVc ) and the volume loss (ΔV) between 900 ± 3×10-5 and 2459 ± 7×10-5 µm3 (SLa < BGa < CGa,b < DBb < EVc ). The vertical height loss (∆VH) was highest for SL (-18.911 ± 3.5) and lowest for EV 55.19 ± 6.3 µm (SLa < BGa < CGa,b < DBb < EVc ). The surface roughness (µm) difference (∆Ra) was lowest for DB (-0.14 ± 0.02) and the highest for EV (0.86 ± 0.42) (DBa < BGa < SLa < CGa < EVb ). BG showed the lowest contact angle difference (∆SW) -2.79 ± 0.8° and EV the highest (3.93 ± 3.1°) (BGa < DBa < SLa < CGa < EVa ). CONCLUSIONS: All polishing instruments performed similarly when ∆Ra values were considered. SL, BG, and CG produced the least material loss. Synthetically bonded rubber bur interspersed with diamond (EV) could not be suggested for polishing MZ.

Preservation of root cementum: a comparative evaluation of power-driven versus hand instruments.

OBJECTIVES: The purpose of this study was to evaluate the effects of three distinct periodontal treatment methods in comparison with hand instrumentation on residual cementum of periodontal diseased teeth. Cementum can influence the activities of periodontal cells and may play an important regulatory role in periodontal treatment. The ideal method for periodontal therapy involves removal of biofilm, calculus and endotoxin while preserving root cementum. MATERIAL AND METHODS: Forty-eight caries free, single-rooted teeth in patients diagnosed with severe chronic periodontitis were treated using four different methods prior to extraction. The teeth were instrumented subgingivally at one approximal site either by hand curettes (HC), piezoelectric ultrasonic scalers (U), piezoelectric ultrasonic scalers following air polishing (U + AP) or air polishing (AP) alone. Following extraction of teeth, instrumented and non-instrumented sites were analysed with a dissecting microscope and SEM for measurement of the amount of and surface characteristics of residual cementum. RESULTS: The percentage of coronal cementum remaining following subgingival instrumentation was 84% for U, 80% for U + AP, 94% for AP and 65% for HC. Although subgingival instrumentation of apical portions of the cementum demonstrated 6% less retained cementum in comparison with coronal portions, the amount of retained cementum with AP was still significantly greater than with HC. SEM results found the smoothest root surfaces were produced by the HC followed by the AP, while root surfaces instrumented by U or U + AP presented grooves and scratches. CONCLUSIONS: This study demonstrated that AP was superior to U devices in preserving cementum, whereas HC were the most effective instruments in removing cementum.

Use of a continual sweep motion to compare air polishing devices, powders and exposure time on unexposed root cementum.

Low abrasive air polishing powders are a viable method for subgingival biofilm removal. This in vitro study evaluated the effects of air polishing using a standard tip on cementum following clinically recommended protocols. Forty-eight teeth were randomly divided into eight groups with six teeth per group. Teeth were treated using either a Hu-Friedy EMS or DENTSPLY Cavitron® air polishing device. One of three glycine powders (Air-flow 25 µm, Clinpro 45 µm, Clinpro+TCP 45 µm) or a sodium bicarbonate powder (NaHCO3  85 µm) was sprayed on cementum using a clinically relevant sweeping motion. Volume and depth of cementum removed after 5 and 90 s exposures were calculated. Surface texture was evaluated using SEMs taken following the last exposure. After 5 s exposures, neither unit nor powder had a substantial effect on volume loss or defect depth. After 90 s exposures, differences between powders existed only for the DENTSPLY unit (p < 0.0001). Pairwise comparisons for this unit revealed mean volume loss and maximum defect depth were greater for NaHCO3 85 µm than the glycine powders (p < 0.0001). The 90 s exposure produced greater mean volume loss and defect depth for all powders (p < 0.0001). SEM images revealed dentinal tubule exposure with all powders; however, exposed tubules were larger and more prevalent for NaHCO3 85 µm. Root surface loss was similar for glycine powders evaluated in this study. Differences in powder performance between units may be related to tip apertures and spray patterns. Additional research is needed to determine if cementum loss is greater than what occurs with conventional biofilm removal methods, such as curets and ultrasonic scalers.

Effect of various polishing systems on the surface roughness and phase transformation of zirconia and the durability of the polishing systems.

STATEMENT OF PROBLEM: Although many systems are used to polish zirconia, a comparison of the performance of zirconia and feldspathic porcelain polishing systems is lacking. PURPOSE: The purpose of this in vitro study was to compare the effects of 3 polishing systems on surface roughness, zirconia phase transformation, and durability of the polishing systems when applied to zirconia and feldspathic porcelain. MATERIAL AND METHODS: Three polishing systems were evaluated: Z1, a zirconia polishing system; Z2, a zirconia polishing system, and F1, a feldspathic porcelain polishing system. Three ceramic systems were evaluated: PR and ZM zirconia specimens (diameter 15 mm, height 2 mm; 23 specimens each) and CB feldspathic porcelain specimens of the same size (15 specimens). A rough surface was created on the 3 types of specimens (15 specimens each) to model an occlusal adjustment under the same conditions. Polishing was carried out with the 3 polishing systems for 2 minutes each. Surface roughness was measured with a 3-dimensional (3D) optical profiler. The surface was also observed with a scanning electron microscopy. X-ray diffraction analysis was performed for 8 PR or ZM zirconia specimens polished by using the Z1 and Z2 systems for 8 minutes to evaluate the phase transformation of zirconia before, during, and after polishing. These specimens were compared and analyzed for phase transformation that might have occurred during the polishing of the specimens. After finishing the surface roughness experiment and the phase transformation experiment, the volumes of the polishers were measured with a 3D volume scanner and compared with those before the experiments to evaluate the durability of the polishing system. A statistical analysis of all data was performed using 2-way ANOVA and the Tukey honest significant difference test (α=.05). RESULTS: The 2 zirconia polishing systems (Z1, Z2) created a significantly (P<.001) smoother surface, regardless of the type of specimens used for polishing, than the feldspathic porcelain polishing system (F1). When polishing treatment was carried out on zirconia specimens for 8 minutes, the maximum percentages of monoclinic phase increased by 0.03% in the Z1 system and by 0.09% in the Z2 system. The volume change for the durability evaluation of the polishing system was 13.35 and 29.37% in the Z1 system, 2.05 and 5.92% in the Z2 system, and 3.60 and 4.95% in the F1 system, respectively. CONCLUSIONS: Zirconia polishing systems created a smoother surface on zirconia than the feldspathic porcelain polishing system. No significant changes in the phase transformation of zirconia were found before and after polishing. Each polishing system showed different levels of wear resistance.

Surface properties of polyetheretherketone after different laboratory and chairside polishing protocols.

STATEMENT OF PROBLEM: Polyetheretherketone (PEEK) can be used as a framework material for fixed dental prostheses. However, information about laboratory and chairside polishing methods is still scarce. PURPOSE: The purpose of this in vitro study was to determine the effects of laboratory and chairside polishing methods on the surface roughness (SR) and surface free energy (SFE) of PEEK, an autopolymerizing poly(methyl methacrylate), and a veneering composite resin. MATERIAL AND METHODS: For each of the 3 materials, 80 specimens were prepared (N=240) and divided into 7 polishing groups and 1 control group (n=10). The 7 groups were split into 4 laboratory protocols: polishing paste (Abraso), a second polishing paste (Opal L), silicone polisher (Ceragum), and diamond grinder (Diagen-Turbo grinder). The other 3 groups were chairside protocols: rainbow technique (Super-Snap kit), polishing paste (Prisma gloss), and a polishing system (Enhance finishing). Machine polishing with SiC P4000 served as the control treatment. The protocols' average SRs and SFEs were measured, and their surface topographies were evaluated with scanning electron microscopy (SEM). The logarithmically transformed data were analyzed using covariance analysis, 2-way and 1-way ANOVA, and partial correlation (α=.05). RESULTS: The polishing protocol exerted the highest influence on SR and SFE values (P<.001; SR: partial eta squared ηP2=.970; SFE: ηP2=.450), followed by material group (P<.001, SR: ηP2=.319; SFE: ηP2=.429). The interaction effect of the binary combinations of the 2 independent parameters (polishing protocol and material group) was also significant (P<.001, SR: ηP2=.681; SFE: ηP2=.365). CONCLUSIONS: Chairside methods presented lower SR values than laboratory methods, and specimens polished using the 2-body mode showed higher SR than did specimens polished using the 3-body mode.

Atomic force microscopy analysis of enamel nanotopography after interproximal reduction.

INTRODUCTION: Interproximal reduction (IPR) removes enamel and leaves grooves and furrows on the tooth surface, which may increase the risk of caries. The aims of this study were to assess the nanotopography of enamel surfaces produced by the most commonly used IPR instruments and to evaluate the effect of polishing after IPR. METHODS: Enamel slabs were cut from the interproximal surfaces of healthy premolars and then treated with diamond burs, strips, or discs, or Sof-Lex polishing discs (3M ESPE, St Paul, Minn). All samples were cleaned by sonication in distilled water. The control group had no IPR performed and was subjected only to cleaning by sonication. The enamel surfaces were assessed using atomic force microscopy. RESULTS: The IPR instruments all produced surfaces rougher than the control sample; however, the samples that received polishing with Sof-Lex discs after enamel reduction were smoother than untreated enamel (P <0.05 for all comparisons). The larger grit medium diamond burs and medium strips generated rougher enamel surfaces than their smaller grit counterparts: fine diamond burs and fine strips (P <0.001). The difference in roughness generated by mesh and curved disks was not statistically significant (P = 0.122), nor was the difference caused by fine strips and mesh discs (P = 0.811) or by fine strips and curved discs (P = 0.076) (surface roughness values for medium bur, 702 ± 134 nm; medium strip, 501 ± 115 nm; mesh disc, 307 ± 107 nm; fine bur, 407 ± 95 nm; fine strip, 318 ± 50 nm; curved disc, 224 ± 65 nm). The smoothest surfaces were created by use of the entire series of Sof-Lex polishing discs after the enamel reduction (surface roughness, 37 ± 14 nm), and these surfaces were significantly smoother than the control surfaces (surface roughness, 149 ± 39 nm; P = 0.017). CONCLUSIONS: Different IPR instruments produced enamel surfaces with varied nanotopography and different degrees of roughness. Enamel surfaces treated with diamond-coated burs were the roughest, followed by diamond-coated strips and diamond coated discs. Polishing with Sof-Lex polishing discs after IPR reduced the enamel surface roughness, and this surface was even smoother than untreated enamel.

Evaluation of Different Polishing Systems and Speeds for Dental Zirconia.

PURPOSE: To evaluate two polishing systems and three polishing speeds on the gloss, roughness, and heat production of yttria stabilized tetragonal zirconia polycrystal (Y-TZP). MATERIALS AND METHODS: A Y-TZP block (Zenostar Zr Translucent) was sectioned into 4-mm-thick sections. Specimens (n = 30 per polishing system) were first wet ground with a fine diamond bur at 200,000 RPM for 15 seconds. The baseline gloss of all specimens was measured in a glossmeter (60° angle) in a direction perpendicular to grinding. Initial surface roughness (Ra ) was determined on an optical profilometer in a direction perpendicular to grinding. The specimens were then polished with either a Dialite ZR Polishing Kit or a CeraMaster Polishing Kit. All grinding and polishing was performed by the same operator calibrated to apply approximately 2 N pressure. The medium grit polisher was used for 30 seconds, repeated for 30 seconds, and then the fine grit polisher was used. After each step, the gloss and roughness of each specimen was remeasured as described previously. Each polishing system was used at 5000, 15,000, and 40,000 RPM (n = 10 for each polish system/speed combination). A group of glazed specimens (n = 10) was evaluated for gloss and roughness as a control. The heat generated for each polishing step was measured with a thermocouple. The gloss and roughness of the specimens were analyzed using a linear mixed model and Tukey-Kramer post-hoc tests. Each step of polishing was compared to the glazed control group with an ANOVA and Dunnett's test. RESULTS: Polishing step, system, and speed were significant (p < 0.05) for gloss and roughness. Examination of system and step interaction was significant for gloss only. Post-hoc analysis revealed that 15,000 RPM produced higher gloss and lower roughness than other speeds. Each progressive step produced an improvement in gloss except for initial 30 seconds with the CeraMaster Coarse (medium polisher; p = 0.34). Roughness was also reduced at each progressive step. No polishing speed/system produced an increase in temperature above 41°C. Both polishing systems were capable of achieving a similar or superior roughness and gloss as the glazed control specimens after the final polishing step at 15,000 RPM. CONCLUSIONS: Fifteen thousand RPM is an optimal polishing speed. Progressing through the polishing sequence significantly improves gloss and roughness and can create similar values as glazed zirconia.

Efficacy of polishing kits on the surface roughness and color stability of different composite resins.

OBJECTIVE: Different polishing kits may have different effects on the composite resin surfaces. The aim of this study was to evaluate the surface roughness and color stability of four different composites which was applied different polishing technique. MATERIALS AND METHODS: Thirty specimens were made for each composite resin group (nanohybrid, GrandioSo-GS; nanohybrid, Clearfil Majesty Esthetic-CME; hybrid, Valux Plus-VP; micro-hybrid, Ruby Comp-RC; [15 mm in diameter and 2 mm height]), with the different monomer composition and particle size from a total of 120 specimens. Each composite group was divided into three subgroups (n = 10). The first subgroup of the each composite subgroups served as control (C) and had no surface treatment. The second subgroup of the each composite resin groups was polished with finishing discs (Bisco Finishing Discs; Bisco Inc., Schaumburg, IL, USA). The third subgroup of the each composite resin was polished with polishing wheel (Enhance and PoGo, Dentsply, Konstanz, Germany). The surface roughness and the color differences measurement of the specimens were made and recorded. The data were compared using Kruskal-Wallis test, and regression analysis was used in order to examine the correlation between surface roughness and color differences of the specimens (α = 0.05). RESULTS: The Kruskal-Wallis test indicated significant difference among the composite resins in terms of ΔE (P < 0.05), and there was no statistically significant difference among composite resins in terms of surface roughness (P > 0.05). Result of the regression analysis indicated statistically significant correlation between Ra and ΔE values (P < 0.05, r2 = 0.74). CONCLUSION: The findings of the present study have clinical relevance in the choice of polishing kits used.

Surface roughness of dental implants and treatment time using six different implantoplasty procedures.

OBJECTIVES: To test whether or not one of six implantoplasty procedures is superior to the others rendering a minimal final implant surface roughness and a short treatment time. MATERIAL AND METHODS: Forty-two one-piece implants were embedded in epoxy resin blocks with 6-mm rough implant surface exposed. The following implantoplasty polishing sequences were applied: Brownie(®) , Greenie(®) sequence (BG) (diamond rotary instruments 106-, 40-, 15-µm grit, Brownie(®) , Greenie(®) silicone polishers); Arkansas stone sequence (AS) (diamond 106-, 40-, 15-µm grit, Arkansas stone torpedo-shaped bur); Short diamond sequence (SD) (diamond 106-, 40-, 4-µm grit); Short diamond sequence with Greenie(®) (SDG) (diamond 106-, 40-, 4-µm grit, Greenie(®) ); Complete diamond sequence (CD) (diamond 106-, 40-, 15-, 8-, 4-µm grit); Complete diamond sequence with Greenie(®) (CDG) (106-, 40-, 15-, 8-, 4-µm grit, Greenie(®) ). The polished neck portion served as a positive control, the untreated sandblasted and acid-etched surface as negative control. Each implant was scanned with a contact profilometer rendering Ra values and Rz values as a measure of surface roughness. The time needed to polish the implant surface for each group was recorded. Simultaneous comparisons between more than two groups were done performing Kruskal-Wallis tests. Comparisons between two groups were analysed using Wilcoxon rank-sum tests. RESULTS: Mean Ra values amounted to 0.32 ± 0.14 µm (BG), 0.39 ± 0.13 µm (AS), 0.59 ± 0.19 µm (SDG), 0.71 ± 0.22 µm (SD), 0.75 ± 0.26 µm (CDG), 0.98 ± 0.30 µm (CD), 0.10 ± 0.01 µm (PC) and 1.94 ± 0.47 µm (NC). Pairwise one-sided comparisons between the test group revealed statistically significant differences (P < 0.05). The shortest treatment time was recorded for group AS (13 ± 2 min) and the longest for CDG (21 ± 2 min) and BG (21 ± 4 min). CONCLUSIONS: Considering final surface roughness and treatment duration, the use of rotary diamond burs in decreasing roughness, followed by an arkansas stone (group AS), appears to be an optimal treatment option.

Evaluation of Bond Strength, Marginal Integrity, and Fracture Strength of Bulk- vs Incrementally-filled Restorations.

PURPOSE: This study evaluated the effect of application technique and preparation size on the fracture strength (FS), microtensile bond strength (µTBS) and marginal integrity (MI) of direct resin composite restorations. MATERIALS AND METHODS: Conservative (5 × 2 × 2 mm) or extended (5 × 4 × 2 mm) preparations below the cementoenamel junction were performed in 140 human maxillary premolars (n = 70 per group). After adhesive application (XP Bond), half of each group was restored with the bulk technique (one 4-mm increment of Surefill SDR Flow plus one 1-mm horizontal capping layer of TPH3 [Spectrum TPH3 resin composite]) and half incrementally (TPH3 in three horizontal incremental layers, 1.5 to 2 mm each), all using a metal matrix band. After storage (24 h at 37°C), the proximal surfaces of each tooth were polished with Sof-Lex disks. For FS measurement, 60 restorations were mounted in a universal testing machine and subjected to a compressive axial load applied parallel to the long axis of the tooth, running at a crosshead speed of 0.5 mm/min. For µTBS testing, 40 teeth were longitudinally sectioned to obtain resin-dentin bonded sticks from the cavity floor (bonded area: 0.8 mm2). Specimens were tested in tension at 0.5 mm/min. The external marginal integrity of both proximal surfaces was analyzed using SEM of epoxy resin replicas. The µTBS, marginal integrity, and fracture resistance data were subjected to two-way ANOVA, and Tukey's post-hoc test was used for pair-wise comparisons (a = 0.05). RESULTS: Fracture resistance, microtensile bond strength, and marginal integrity values were not statistically significantly affected by application technique or preparation size (p = 0.71, p = 0.82, and p = 0.77, respectively). CONCLUSIONS: The use of a bulk-fill flowable composite associated with a conventional resin composite as a final capping layer did not jeopardize the fracture strength, bond strength to dentin, or marginal integrity of posterior restorations.

Ceramic Repair Without Hydrofluoric Acid.

PURPOSE: To evaluate the bond strength between composite resin and feldspathic ceramic following repair protocols with and without hydrofluoric acid and aging by thermocycling. MATERIALS AND METHODS: Forty-eight glass feldspathic ceramic blocks (8 x 8 x 6 mm) were divided into three groups on the basis of their surface repair treatment: 1. 10% hydrofluoric acid + Signum Ceramic Primer I + Signum Ceramic Primer II (control group); 2. abrasive rubber tips + Signum Ceramic Primer I + Signum Ceramic Primer II (test group); 3. Signum Ceramic Primer I + Signum Ceramic Primer II (negative control group). The treated surface of each block was built up with composite and then sectioned to produce nontrimmed bars (adhesive area = 1 mm²). Half of the bars from each group were aged by 6000 cycles of 30-s immersions in water baths at 5°C and 55°C, with a transfer time of 2 s. The other bars were immediately subjected to microtensile bond strength testing. The mean bond strength for each block was then recorded and submitted to two-way ANOVA and Tukey's test (α = 0.05). RESULTS: The aging protocol influenced the bond strength values of all groups (p = 0.000). The non-aged groups submitted to surface treatment protocols 1 (13.1 ± 2.5 MPa) and 2 (11.5 ± 5.1 MPa) presented the highest bond strength values. CONCLUSIONS: The interface bond strength of all groups was susceptible to aging. Surface treatment protocol 2, with abrasive rubber tips and no hydrofluoric acid, appeared to be the most promising option, as the resulting bond strength values were similar to those of the control group.

Efficiency of powered systems for interproximal enamel reduction (IER) and enamel roughness before and after polishing-an in vitro study.

OBJECTIVE: This aims to evaluate the efficiency of three different powered interproximal enamel reduction (IER) systems and to assess enamel roughness before and after polishing using different polishing times. MATERIAL AND METHODS: Four metal strips of the G5 ProLign Set (swissdentacare, SDC, Grancia, Switzerland), four segmental discs of the ASR-Set 4594 and two sonic tips of the SonicLine Set (both Gebr. Basseler GmbH & Co. KG, Komet, Lemgo, Germany) were evaluated. Human extracted incisors served as the medium. Enamel reduction was determined in five intervals of 15 s each. Polishing was performed for 15 and 30 s using the manufacturers' recommended polishing systems. Enamel roughness (Ra) was quantitatively assessed by confocal laser scanning microscopy (CLSM). RESULTS: Significant differences in terms of enamel reduction were found among the working ends of all tested systems. The time needed to remove 0.1, 0.2 and 0.3 mm of enamel was determined. Surface analysis showed significantly higher mean Ra values for nine out of ten working ends before polishing. This was still the case for five working ends after 15 s and for two after 30 s of polishing. CONCLUSION: The graining and the system used have a significant influence on enamel reduction. The time needed for polishing depends on the last working end used; a polishing time of 30 s is not always appropriate. CLINICAL RELEVANCE: Knowledge about the cutting efficiency of powered IER working ends might help the clinician to estimate better the amount of enamel reduction during the stripping process.

Analysis of Effectiveness of Different Rotational Instruments in Implantoplasty: An In Vitro Study.

OBJECTIVE: To analyze the temperature increase in the implant, adjacent bone, procedure time, and roughness provided by different rotatory instruments in the implantoplasty procedure. MATERIAL AND METHODS: Three types of rotational instruments were used to evaluate the implant surface wear, divided according to their surface features: Group 1 (G1) diamond, Group 2 (G2) tungsten carbide, and Group 3 (G3) multilaminar. For the roughness test, a control group was included for comparison with the test groups. RESULTS: The temperature variation was statistically significant in the implant (P < 0.05) where G2 showed the lowest variation. There was no statistically significant difference between the 3 groups regarding the temperature increase measured in the bone (P > 0.05). The difference of wear time was statistically significant (P < 0.05) with faster results for G3. In the surface roughness analyses, there was a statistically significant difference (P < 0.05) between the control group and the test groups. Among the 3 test groups, the difference between measurements was not statistically significant (P > 0.05). CONCLUSION: All tested rotatory instruments performed the same level of surface roughness in the implantoplasty. The tungsten carbide bur caused a minor change in the implant temperature. The multilaminar bur performed a faster wear time. More in vivo studies are necessary to conclude which is the best rotatory instrument for implantoplasty.

Effects of Novel Finishing and Polishing Systems on Surface Roughness and Morphology of Nanocomposites.

OBJECTIVES: The purpose of this in vitro study was to evaluate the effects of different finishing/polishing techniques on the surface roughness of nanocomposites after thermocycling aging. MATERIALS AND METHODS: Five contemporary resin-based composites (Clearfil Majesty ES-2, Filtek Z550, Estelite∑Quick, Zenit, Filtek Z250) were tested. For each resin-based composite, 50 disc-shaped specimens were prepared and groups were divided into five subgroups according to the finishing/polishing methods (n = 10): control, finishing/polishing brush, finishing/polishing disc, and two different finishing/polishing wheels. Before and after aging, the surface roughness of specimens was measured. For each treatment method two samples were analyzed using a scanning electron microscope. Two-way analysis of variance and paired samples t-tests were used to evaluate the data and the means were compared by Bonferroni tests (p ≤ 0.05). RESULTS: Before aging, the Filtek Z250 resin with the Mylar strip group showed the lowest surface roughness (Ra) value (0.13 ± 0.03 µm, p < 0.05) and the Clearfil Majesty ES 2 resin with Occlubrush finishing/polishing system showed the highest (0.7 ± 0.13 µm, p < 0.05). After aging, the Clearfil Majesty ES 2 resin with the Mylar strip group showed the highest surface roughness (Ra) value (0.96 ± 0.4 µm) and the Clearfil Majesty ES 2 resin with the Sof-Lex aluminum oxide disc finishing/polishing system showed the lowest surface roughness (Ra) value (0.25 ± 0.06 µm, p < 0.05). CONCLUSIONS: Composite type and finishing/polishing method significantly affected the surface roughness of composites before and after thermocycling aging. CLINICAL SIGNIFICANCE: There were significant interactions between finishing/polishing methods and composite types for surface roughness. The results give clinicians some flexibility in choosing appropriate finishing/polishing techniques for each resin composite material. (J Esthet Restor Dent 28:247-261, 2016).

Subjective qualitative assessment of the finish line of prosthetic preparations submitted to different finishing instruments.

STATEMENT OF PROBLEM: Different instruments have been developed to improve crown finish lines after conventional preparation with diamond rotary instruments. However, more evidence on the effectiveness of these instruments is required. PURPOSE OF STUDY: The purpose of this in vitro study was to assess the effectiveness of 4 different instruments used for cervical margin finishing in regard to the external line angle (ELA). MATERIAL AND METHODS: Forty-eight freshly extracted third molar teeth with similar dimensions were conventionally prepared for crowns and randomly allocated into 4 groups (n=12) according to the finishing instrument: hand trimmer (HT), tungsten carbide bur (TCB), ultrasonic instrument (UI), and diamond rotary instrument (DRI) mounted in a contra angle handpiece with reduced speed. Photomicrographs from the margin profiles of each tooth were obtained with scanning electron microscopy (×40) before and after finishing procedures. The images were qualitatively analyzed (scores 1-4) by 9 experienced dental professionals. Average results were assessed with the paired t test and repeated measures ANOVA followed by Tukey HSD test (α=.05). RESULTS: HT, TCB, and UI demonstrated no significant differences between unfinished and finished mean ELA scores. DRI was the only group to demonstrate a significantly improved ELA (P<.001). Except for HT in relation to TCB (P=.989), all the other groups demonstrated statistically significant different ELA scores. CONCLUSION: DRI mounted in a contra angle handpiece was the only finishing instrument capable of significantly improving the ELA, while TCB and UI produced nonsignificant improvement, and HT was detrimental to the ELA.

Evaluation of various polishing systems and the phase transformation of monolithic zirconia.

STATEMENT OF PROBLEM: Although a well-polished monolithic zirconia surface is essential, insufficient comparative studies on the constituents and efficacy of polishing systems have been conducted. PURPOSE: The purpose of this in vitro study was to analyze the abrasive constituents and compare the polishing effectiveness of 6 zirconia polishing systems, including their potential influence on the phase transformation of monolithic zirconia. MATERIAL AND METHODS: The compositions of 6 zirconia polishing systems were analyzed using energy dispersive spectroscopy (EDS). Sintered and high-speed ground monolithic zirconia specimens were used as control groups (n=14 specimens per group). Test groups (n=168) were pretreated identically to the control group and arbitrarily divided into 12 groups to examine 6 polishing systems for 2 polishing periods (60 or 120 seconds). The surfaces were characterized by a surface profiler and various analytic techniques, including x-ray diffraction (XRD) analysis. The data were analyzed using 2-way ANOVA and multiple comparisons and the Bonferroni method (α=.05). RESULTS: The abrasives were primarily composed of C, O, and Si. Diamond was identified as the main abrasive and SiC as the supplementary abrasive in the polishing systems. No significant differences were observed for the 60- or 120-second polishing times (P>.05). Four products had significantly lower surface roughness values than the other 2 (P<.001). The occlusal-adjustment-simulating pretreatment and polishing processes did not cause phase transformations in the zirconia specimens. CONCLUSIONS: The monolithic zirconia polishing systems contained diamond and SiC abrasives. All zirconia polishing systems showed clinically acceptable results, and 4 systems exhibited lower surface roughness. Phase transformation did not occur during polishing procedure.

Treatment of peri-implant mucositis using a glycine powder air-polishing or ultrasonic device: a randomized clinical trial.

AIM: To evaluate the clinical treatment effects of a glycine powder air-polishing or ultrasonic device on peri-implant mucositis. MATERIALS AND METHODS: Thirty-seven patients with one implant diagnosed with peri-implant mucositis (probing depth ≥4 mm (0.2N) and bleeding on probing (BOP) (primary outcome)) were randomly assigned to treatment with either glycine powder air-polishing (GPAP) or ultrasonic (US) debridement. Treatment was performed at baseline and at 3 and 6 months. Professional supra gingival cleaning was performed at 9 and 12 months. Oral hygiene instructions were reinforced at each visit. RESULTS: At 12 months there was a statistically significant reduction in mean plaque score, bleeding on probing and number of periodontal pockets ≥4 mm within the treatment groups compared to baseline. The percentages of diseased sites were significantly reduced for both groups. CONCLUSIONS: Treatment with a glycine powder air-polishing or an ultrasonic device is effective in non-surgical treatment of peri-implant mucositis.

Cost-effectiveness of non-surgical peri-implantitis treatments.

AIM: The purpose of the present study was to assess the cost-effectiveness of various alternatives of non-surgical peri-implantitis treatment. MATERIALS AND METHODS: A decision analytical model was constructed and populated with parameter estimates from recent literature for reduction in pocket probing depth (PPD) in response to eight different treatment alternatives. A micro-costing approach combined with an online expert survey was applied to simulate a decision-making scenario taking place in Germany. The treatment alternatives providing the most advantageous cost/outcome combinations were identified according to the net benefit criterion. Uncertainties regarding model input parameters were incorporated via simple and probabilistic sensitivity analysis based on Monte Carlo simulation. RESULTS: In the base case scenario, debridement alone, Air-Flow, debridement combined with PerioChip, and debridement combined with local antibiotics were identified as treatment strategies with comparably better value for money than Er:YAG laser monotherapy, Vector System, debridement combined with CHX, and photodynamic therapy. Sensitivity analysis revealed considerable decision uncertainty corresponding to limited evidence about different treatment alternatives for peri-implantitis treatment. CONCLUSIONS: Derivation of robust treatment recommendations for peri-implantitis requires more comprehensive and patient-centred evidence on peri-implantitis treatments.