Surface Of Restorative Materials Research Articles

The Effect of Usage of Antiasthmatic Inhalers on Color Stability and Surface Roughness of Dental Restorative Materials: An In Vitro Study.

Increased demand for esthetics by parents and children has resulted in the use of tooth-colored restorative materials. Children with chronic respiratory conditions like asthma use inhalers which have shown to affect the surface of restorative materials. Hence, the aim of the present study was to evaluate the effect of antiasthmatic inhalers on color stability and surface roughness of three restorative materials. Forty samples each of three dental restorative materials: group A: glass ionomer cement (GIC), group B: alkasite restorative material, and group C: composite resins were prepared. Each group was further divided into two subgroups of 20 samples each according to the inhaler used. All the specimens were polished using polishing discs and stored in artificial saliva in order to simulate the oral environment. The baseline color value and surface roughness of all the samples were measured using a spectrophotometer and a profilometer, respectively. Group 1 and group 2 were exposed to 0.31 mg of salbutamol sulfate and 20 mg formoterol fumarate in combination with budesonide, respectively, for every 12 hours, for a period of 15 days following which the samples were evaluated for color changes and surface roughness. The data obtained was subjected to statistical analysis and level of significance was set at p < 0.05. Exposure to both the inhalers caused a change in color and surface roughness in all three restorative materials. There was a significant change in the color of GIC and composite resin (ΔE > 3.3), following exposure to both the inhalers (p < 0.05). The change in color of alkasite restorative material was not significant. A significant increase in the surface roughness of composite resin from 0.56 ± 0.14 to 0.67 ± 0.19 was seen following 15 days' exposure to formoterol in combination with budesonide inhaler (p < 0.05). Following exposure, both the inhalers had an equal effect on color and surface roughness of all three restorative materials. Alkasite restorative material showed greater resistance to change in color and surface roughness when exposed to antiasthmatic inhalers, compared to GIC and composite resin. Thus, children who use inhalers and nebulizers should be advised to implement more precautionary oral hygiene measures and periodic dental visits.

Evaluation of the effects of whitening toothpaste containing nanohydroxyapatite on surface roughness and color change in restorative materials.

The effects of whitening toothpastes containing nanohydroxyapatite on the surfaces of restorative materials are not well known. This study evaluated the changes in surface roughness and color of coffee-stained restorative materials after brushing with nanohydroxyapatite and other whitening toothpastes. Disc-shaped specimens were formed using microhybrid, nanohybrid, and supra-nano-filled composite (n = 30) and stained with a coffee solution. A brushing simulation was applied with toothpastes containing nanohydroxyapatite (Dentiste Plus White), perlite (Signal White System) and hydrogen peroxide (Colgate Optic White) for 7, 15, and 30 days. Color and surface roughness measurements were taken before and after brushing. Color change (∆E00) was calculated using the CIEDE2000 system. Supra-nano-filled composite-Dentiste Plus White, supra-nano-filled composite-Colgate Optic White, and nanohybrid composite-Signal White System were the groups with the greatest color change observed on the 7th, 15th, and 30th days, respectively. The smallest color change was seen in the microhybrid composite-Signal White System, microhybrid composite-Dentiste Plus White, and nanohybrid composite-Dentiste Plus White groups on the 7th, 15th, and 30th days, respectively. No significant surface roughness changes were observed in the nanohybrid composite-Dentiste Plus White, supra-nano-filled composite-Colgate Optic White, supra-nano-filled composite-Dentiste Plus White, or supra-nano-filled composite-Signal White System groups. Whitening toothpaste containing nanohydroxyapatite provided a high degree of color change in the short term and did not create significant surface roughness in nanohybrid or supra-nano-filled composites.

Dynamic killing effectiveness of mouthrinses and a d-enantiomeric peptide on oral multispecies biofilms grown on dental restorative material surfaces

ObjectiveTo evaluate the dynamics of killing of oral multispecies biofilms grown on dental restorative materials by commercially available mouthrinses and a d-enantiomeric peptide. MethodsFour composite resins (3 M Supreme, 3 M Supreme flow, Kerr Sonicfill, and Shofu Beautifil II) and one glass ionomer (GC Fuji II) were used as restorative materials. Plaque biofilms were grown on the surfaces of restorative material discs for 1 week. The surface roughness and biofilm attachment were assessed by atomic force microscopy and scanning electron microscopy. One-week-old biofilms grown anaerobically at 37 °C were exposed to each of five solutions for one minute (twice daily for seven days): Listerine Total care and Paroex Gum mouthrinses, 0.12% chlorhexidine, 0.001% d-enantiomeric peptide DJK-5, and sterile water. The dynamic variation of the biovolume of the biofilms and the percentage of dead bacteria were monitored and analyzed using confocal laser scanning microscopy. ResultsAll restorative materials had similar surface roughness with intact biofilm attachment. The percentage of dead bacteria and biovolume of biofilms treated by each oral rinse solution remained constant between days 1 and 7, with no statistically significant difference. DJK-5 showed the highest percentage of dead bacteria (up to 75.7%; cf. ∼20–40% for other mouthrinses) of all solutions tested within 7 days. ConclusionsDJK-5 outperformed conventional mouthrinses in killing bacteria in oral multispecies biofilms grown on dental restorative materials. Clinical significanceThe antimicrobial peptide DJK-5 is effective against oral biofilms and serves as a promising candidate for the development of future mouthrinses to improve long-term oral hygiene.

Proteomic profile of in situ acquired pellicle on tooth and restorative material surfaces

ObjectivesTo evaluate and compare the proteomic profile of acquired pellicle on smooth bovine tooth and tooth-coloured restorative materials, including resin composite (RC), glass ionomer cement (GIC), and casein phosphopeptide-amorphous calcium phosphate modified GIC (CPP-ACP GIC). MethodsTwo-hour in situ pellicles on tooth/materials specimens mounted in oral appliances worn by ten healthy adults were investigated. Pellicle proteins and corresponding unstimulated whole saliva were quantitatively analysed through liquid chromatography-tandem mass spectrometry. ResultsSignificantly higher amounts of protein were adsorbed onto tooth surface than restorative materials tested (4.11 ± 0.69 vs. 2.54 ± 0.38/2.98 ± 0.80/3.01 ± 0.37 µg, RC/GIC/CPP-ACP GIC). From the ten participants, 1,444 (487–1,086/person), 1,454 (645–1,051/person), 1,731 (454–1,475/person), or 1,597 (423–1,261/person) pellicle proteins were detected at least once on bovine tooth, RC, GIC, or CPP-ACP GIC, respectively, and with 1,072 (304–793/person) salivary proteins identified. Comparative quantification revealed minor differences between tooth and restorative materials pellicle profiles. High inter-individual variations in pellicle protein composition were demonstrated. Compared to the salivary protein profile, 214/57 proteins showed significantly increased/decreased abundance in pellicle formed on at least one substrate (fold change > 3.325/fold change < 0.301). Gene Ontology enrichment analysis showed some pellicle proteins detected with increased affinity to tooth/material surface were identified as being related to “calcium-dependent protein binding” or “cell-cell adhesion mediator activity”. ConclusionSimilar protein quantity and composition was observed in 2 h in situ pellicles formed on different smooth restorative material surfaces. The proteomic profile of pellicles appeared distinct from that of the corresponding unstimulated whole saliva. Clinical SignificanceHost backgrounds appeared more influential on the proteomic profile of the in situ acquired pellicle than the underlying substrate characteristics among systemically and orally healthy adults. Pellicle proteins preferentially adsorbed on tooth/materials were putatively associated with calcium ion homeostasis or host-microbiota interaction.

Evaluation of 12-hour in situ bacterial colonization on smooth restorative material surfaces

ObjectivesThe aim of this study was to investigate 12 h in situ bacterial colonization on different restorative materials with smooth surfaces. MethodsThe restorative materials examined included resin composite (RC), a glass ionomer cement (GIC), casein phosphopeptide-amorphous calcium phosphate modified GIC (CPP-ACP GIC, 3% w/w), and control bovine teeth. Polished bovine tooth and material slabs (average roughness < 0.2 μm) were prepared. Specimens were mounted in a custom-made removable appliance, then placed for 12 h in the oral cavities of ten systemically and orally healthy volunteers (23-30 year-old). The colonized bacteria on the restorative materials were evaluated by real-time quantitative polymerase chain reaction (q-PCR) and 16S rRNA gene sequencing. ResultsThe in situ bacterial colonization, in terms of both total bacterial biomass and bacterial community composition, was similar among the restorative materials tested. The microbiota of early plaque comprised similar “core microbiota”, which were dominated by species within the genera of Streptococcus, Haemophilus, Neisseria, Gemella, and Prevotella, regardless of the type of underlying surface. Beta-diversity analyses revealed that most differences in the microbiota profile among samples were attributed to inter-individual variation, rather than the different materials. The microbial community composition of 12 h in situ plaque appeared different from that of whole saliva. ConclusionsSimilar bacterial composition of 12-h in situ plaque was observed on smooth material and tooth surfaces tested, including species mainly from within the Streptococcus, Haemophilus, Neisseria, Gemella, or Prevotella genera. Clinical significanceThe high inter-individual variation in plaque microbiota observed in this study, which outweighed the potential differences among various materials, demonstrated the importance of an in situ biofilm model as well as consideration of the host oral an microbial backgrounds when evaluating the bacterial colonization on restorative materials.

Establishment of novel in vitro culture system with the ability to reproduce oral biofilm formation on dental materials

Intensive research has been conducted with the aim of developing dental restorative/prosthetic materials with antibacterial and anti-biofilm effects that contribute to controlling bacterial infection in the oral cavity. In situ evaluations were performed to assess the clinical efficacy of these materials by exposing them to oral environments. However, it is difficult to recruit many participants to collect sufficient amount of data for scientific analysis. This study aimed to assemble an original flow-cell type bioreactor equipped with two flow routes and assess its usefulness by evaluating the ability to reproduce in situ oral biofilms formed on restorative materials. A drop of bacterial suspension collected from human saliva and 0.2% sucrose solution was introduced into the assembled bioreactor while maintaining the incubation conditions. The bioreactor was able to mimic the number of bacterial cells, live/dead bacterial volume, and volume fraction of live bacteria in the in situ oral biofilm formed on the surface of restorative materials. The usefulness of the established culture system was further validated by a clear demonstration of the anti-biofilm effects of a glass-ionomer cement incorporating zinc-releasing glasses when evaluated by this system.

Analysis of the structural reliability of dental filling under the effect of mouthwash G.U.M

The application of structural reliability analysis has become very important to ensure the strength of the studied structural design, as it presents results that help in giving evidence about the acceptance of that design according to the materials used under specific operating conditions. In this research an experiment was done, to find out the effect of G.U.M mouthwash on cured and re-cured Visible Light Cured (VLC) composite dental filling material, made according to agreed international standards, where many studies have documented that the surface of restorative materials placed on the tooth may also be affected by the chemical effect of different types of oral health care products, and the experiment was analyzed mathematically by applying structural reliability analysis to know the probability of structural failure when dental filling were exposed to the mouthwash G.U.M (Operational conditions), using analysis technique: the D-vine copula. The results were that the probability of structural failure gave an indication from which to infer the extent to which the experiment was accepted or rejected.

Effect of surface sealant on surface roughness and bacterial adhesion of bulk-fill composites

Surface sealants are reported to ensure surface smoothness and improve the surface quality of composite restorations. These sealants should also reduce the bacterial adhesion on composite surfaces however, there is not much information regarding their performance on bulk-fill composite materials. The aim of this study was to evaluate the effect of surface sealant application on surface roughness and bacterial adhesion of various restorative materials. Disc-shaped samples were prepared from a compomer, a conventional composite and three bulk-fill composites. Specimens of each group were divided into two groups (n = 9): with/without surface sealant (Biscover LV, [BLV]). Surface roughness values were examined by profilometry and two samples of each group were examined for bacterial adhesion on a confocal laser scanning microscope (CLSM). Bacterial counts were calculated by both broth cultivation and microscopic images. Results were analyzed with one-way ANOVA and Bonferroni/Dunn tests. Following the BLV application, there was a decrease in the surface roughness values of all groups however, only Tetric N-Ceram Bulk and Beautifil-Bulk groups showed significantly smoother surfaces (p &lt; 0.001). There were no significant differences among material groups without BLV application. Evaluating bacterial adhesion after BLV application, conventional composite had the lowest values among all followed by the compomer group. Beautifil-Bulk had significantly the highest bacterial adhesion (p &lt; 0.05), followed by Tetric N-Ceram Bulk group. Without BLV application, there was no significant difference among bacterial adhesion values of groups (p &gt; 0.05). CLSM images showed cell viability in groups. Bulk-fill composites showed higher bacterial adhesion than conventional composite and compomer materials. The surface sealant was found to be highly effective in lowering bacterial adhesion, but not so superior in smoothing the surfaces of restorative materials. So, surface sealants could be used on the restorations of patients with high caries risk.

Effect of pediatric multivitamin syrups and effervescent tablets on the surface microhardness and roughness of restorative materials: An in vitro study

Background/purposeMultivitamin syrups and effervescent tablets are commonly used for dietary support in children; however, these preparations may have detrimental effects on the surface of restorative materials. The aim of this study was to evaluate the effect of two multivitamin syrups and two effervescent tablets taken daily on the surface microhardness and roughness of two different restorative materials. Materials and methodsThe study groups were comprised of a conventional glass ionomer cement, Ketac Molar, and a giomer, Beautifil II. A total of 140 disc-shaped specimens were prepared and randomly assigned to 5 subgroups. The samples were immersed in 4 multivitamins (Supradyne syrup, Supradyne effervescent, Sambucol syrup, Sambucol effervescent) and deionized water (control group) for 2 min once a day for 28 days. Surface microhardness and roughness measurements were recorded at baseline and on the 7th, 14th, 21st and 28th days. Surface microhardness was measured using a Vickers hardness tester and surface roughness was determined using a profilometer. ResultsFor all subgroups; the surface microhardness values of the Ketac Molar and Beautifil II demonstrated a statistically significant decrease from the baseline to the 28th day measurements (p < 0.05), while the surface roughness displayed increased values that were found to be statistically significant (p < 0.05). The Ketac Molar surface roughness values were significantly higher than Beautifil II in all subgroups for all measurement days (p = 0.0001). ConclusionThe prolonged use of multivitamin syrups and effervescent tablets may have negative effects on the physical properties of restorative materials.

Human Gingival Epithelial Growth In Vitro on a Polymer-Infiltrated Ceramic Network Restorative Material.

To investigate the growth of primary human gingival epithelial (HGE) cells on polymer-infiltrated ceramic network (PICN) material (Vita Enamic) with different surface roughnesses. PICN material specimens were polished with either silica carbide paper (grit-polished) or the manufacturer's polishing wheels (wheel-polished), and the surface roughness (Ra ) measured. HGE cells were seeded and grown for 1, 3, or 6 days. Growth on tissue culture plastic was used as a control. Non-linear regression analysis was used to examine the effect of surface roughness on cell growth. HGE cell growth on tissue culture plastic fitted an exponential growth model over the 6-day experimental period (R2 = 0.966). Through day 6, cell density on PICN decreased with increasing surface roughness, with a fit to an exponential decay model (R2 = 0.666). A threshold Ra value of 0.254 μm (95% CI 0.177-0.332) was determined as an upper limit for exponential growth. Cell growth was greatest on the group of specimens with Ra value below 0.127μm. Specimens polished by the manufacturer's method produced surface roughness of 0.118 μm and below. PICN material polished to a smooth surface (Ra < 0.254 μm) resulted in exponential growth of HGE cell growth compared to rough surfaces. Polishing PICN material as smooth as possible (below a Ra of 0.127 μm) was found to maximize epithelial cell growth on the PICN material surface. The manufacturer's polishing method achieved a sufficiently smooth surface. These results are contrary to previous research regarding surface roughness of transgingival implant restoration components. The study results suggest that smoother restorative material surfaces could improve peri-implant soft tissue health.

Surface microhardness of different restorative materials exposed to candida albicans biofilm isolated from the oral cavity of hiv-infected children

Introduction: Candida albicans is one of the microrganisms that most often colonizes the oral cavity of HIV-infected children. This fungus secretes organic acids, which decrease the pH of the oral cavity; an environment that is already particularly acidic in HIV-Infected children because of their hypercaloric diets, use of sugary medicines, and poor oral hygiene. Considering the large number of dental restorations and the high prevalence of caries in this population, these conditions, including the metabolism of C. albicans, can potentially cause problems in terms of the surface of restorative materials. Objective: Therefore, the aim of this study was to evaluate, in vitro, the potential of C. albicans isolated from the dental biofilm of HIV-infected children to cause surface demineralization of the restorative materials used in pediatric dentistry. Material and method: Forty-four blocks of four different materials (2 resins, 1 compomer, and 1 glass ionomer cement) were made and separated into four groups (n = 11). All blocks were submitted to initial surface microhardness (ISM) analysis. Subsequently, each block was exposed to C. albicans biofilm, formed from a 1 mL standard suspension containing 105 yeasts/mL, over seven days. The blocks were then cleaned and kept at 4 °C until being submitted for measurement of the final surface microhardness (FSM). The Mann-Whitney test was used for intragroup comparisons between ISM and FSM values. Results: The percentage of microhardness loss (% MHL) values between the four groups were compared using the Kruskall- Wallis test (95% CI). The ISM values ranged from 63.54 ± 11.41 to 77.92 ± 10.91, with no statistical differences being found (p = 0.76). After exposure to biofilm, no significant changes in surface microhardness were observed when comparing the values of ISM and FSM, except for group 3 (compomer VitremerTM), which had an FSM value of 40.45 ± 7.57 (p = 0.001). The % MHL of the compomer (group 3) was significantly higher (41.16%) than the other groups (5.35% group 1; 7.02% group 2; and 9.57% group 3) (p = 0.036). Conclusion: It can be concluded that, in vitro, C. albicans isolated from the dental biofilms of HIV-infected children can cause significant reduction in the surface microhardness of compomer compared with other materials.

Lithium disilicate glass-ceramic vs translucent zirconia polycrystals bonded to distinct substrates: Fatigue failure load, number of cycles for failure, survival rates, and stress distribution

The present study evaluated the fatigue behavior of monolithic translucent zirconia polycrystals (TZ) and lithium disilicate glass-ceramic (LD) bonded to different substrates. Disc-shaped specimens of ceramic materials TZ and LD were bonded to three substrates with different elastic modulus (E) (fiber-reinforced composite (FRC) – softest material, E = 14.9 GPa; titanium alloy (Ti) – intermediary properties, E = 115 GPa; and zirconia (Yz) – stiffest material, E = 210 GPa). The surfaces were treated and bonded with resin cement (disc-disc set-up). Fatigue testing followed a step-stress approach (initial maximum load = 200 N for 5000 cycles, incremental step load = 200 N for 10,000 cycles/step). The fatigue failure load and number of cycles until failure were recorded and statistically analyzed. Fractographic and finite element (FEA) analyzes were conducted as well. TZ ceramic depicted higher fatigue failure load, number of cycles until failure, and survival probabilities than LD, irrespective of the substrate. Moreover, TZ and LD presented better fatigue behaviors when bonded to substrates Ti and Yz in comparison to FRC. FEA revealed lower tensile stresses at restorative material when bonded to stiffer substrates. Fractography showed that the fracture origin started at bottom surface of restorative material (except for TZ bonded to Yz, in which crack initiated at load contact point). Translucent zirconia polycrystals present superior mechanical behavior than lithium disilicate glass-ceramic. The substrate type influences the mechanical performance of monolithic dental ceramics (stiffer substrates lead to better fatigue behavior).

Does Finishing and Polishing of Restorative Materials Affect Bacterial Adhesion and Biofilm Formation? A Systematic Review.

Biofilm (bacterial plaque) accumulation on the surface of restorative materials favors the occurrence of secondary caries and periodontal inflammation. Surface characteristics of restorations can be modified by finishing and/or polishing procedures and may affect bacterial adhesion. The aim of this systematic review was to characterize how finishing and polishing methods affect the surface properties of different restorative materials with regard to bacterial adhesion and biofilm formation. Searches were carried out in MEDLINE-PubMed, EMBASE, Cochrane-CENTRAL, and LILACS databases. From 2882 potential articles found in the initial searches, only 18 met the eligible criteria and were included in this review (12 with in vitro design, four with in situ design, and two clinical trials). However, they presented high heterogeneity regarding materials considered and methodology for evaluating the desired outcome. Risk bias analysis showed that only two studies presented low risk (whereas 11 showed high and five showed medium risk). Thus, only descriptive analyses considering study design, materials, intervention (finishing/polishing), surface characteristics (roughness and surface free energy), and protocol for biofilm formation (bacterial adhesion) could be performed. Some conclusions could be drawn: the impact of roughness on bacterial adhesion seems to be related not to a roughness threshold (as previously believed) but rather to a range, the range of surface roughness among different polishing methods is wide and material dependent, finishing invariably creates a rougher surface and should always be followed by a polishing method, each dental material requires its own treatment modality to obtain and maintain as smooth a surface as possible, and in vitro designs do not seem to be powerful tools to draw relevant conclusions, so in vivo and in situ designs become strongly recommended.

The effect of brushing with nano calcium carbonate and calcium carbonate toothpaste on the surface roughness of nano-ionomer

Nanotechnology developments in dentistry have resulted in the development of nano-ionomer, a new restorative material. The surface roughness of restorative materials can increase bacteria adhesion and lead to poor oral hygiene. Abrasive agents in toothpaste can alter tooth and restorative material surfaces. The aim of this study is to identify the effect of brushing with nano calcium carbonate, and calcium carbonate toothpaste on surface roughness of nano-ionomer. Eighteen nano-ionomer specimens were brushed with Aquabidest (doubledistilled water), nano calcium carbonate and calcium carbonate toothpaste. Brushing lasted 30 minutes, and the roughness value (Ra) was measured after each 10 minute segment using a surface roughness tester. The data was analyzed using repeated ANOVA and one-way ANOVA test. The value of nano-ionomer surface roughness increased significantly (p<0.05) after 20 minutes of brushing with the nano calcium carbonate toothpaste. Brushing with calcium carbonate toothpaste leaves nano-ionomer surfaces more rugged than brushing with nano calcium carbonate toothpaste.

Evaluation of candida albicans biofilm formation on various dental restorative material surfaces.

Candida adhesion to any oral substrata is the first and essential stage in forming a pathogenic fungal biofilm. In general, yeast cells have remarkable potential to adhere to host surfaces, such as teeth or mucosa, and to artificial, nonbiological surfaces, such as restorative dental materials. This study compared the susceptibility of six dental restorative materials to Candida albicans adhesion. Cylindrical samples of each material were made according to the manufacturersa instructions. The antifungal effect of the samples on C. albicans was determined with the disc-diffusion method. The samples were put in plates with sterile Mueller Hinton and Sabouraud dextrose agar previously seeded with C. albicans. After the incubation period, the inhibition zone around each sample was evaluated. To evaluate the biofilm formation, the XTT technique and scanning electron microscopy (SEM) were used. No inhibition zone was observed around the samples. According to the XTT assays, the amalgam samples revealed the lowest quantity of biofilm formation (P > 0.001). The highest median XTT values, significantly higher than the other materials (P < 0.001), were found for the composite and the compomer samples. Within the SEM examination, the amount of candidal growth was significantly lower on the resin-modified glass ionomer and glass-ionomer cement samples. The compomer and the composite samples showed more candidal adhesion. This finding emphasizes the use of glass ionomer restorative cements and amalgam to reduce C. albicans adhesion to dental restorative materials especially in people with weakened immune systems, neutropenia, and cancer.

Effect of the lasers used in periodontal therapy on the surfaces of restorative materials.

The present study aimed to reveal potential damage of the lasers, which are used as an alternative to manual instruments in periodontal therapy, might cause to the surface of restorative materials. Four different restorative materials were used: a glass-ionomer cement (GIC), a flowable composite (FC), a universal composite (UC) and an amalgam. Ten cylindrical samples (8 mm × 2 mm) were prepared for each restorative material. Two laser systems were used in subgingival curettage mode; an 940 nm diode laser (Epic Biolase, Irvine, CA) and an Er,Cr:YSGG laser (Waterlase iPlus, Biolase, Irvine, CA). After laser irradiation, roughness of the sample surfaces was measured using a profilometer. Additionally, atomic force microscopy (AFM) and scanning electron microscopy (SEM) analyses were performed to evaluate the morphology and surface deformations of the restorative materials and surfaces. The laser irradiation did not affect the surface roughness of any restorative materials relative to that of the control group (p > 0.05) except for the Er,Cr:YSGG treatment on GIC (p < 0.05). SEM and AFM images verified the results of the surface roughness tests. Within the limitations of the present study, it was demonstrated that Er,Cr:YSGG and diode lasers, aside from the Er;Cr:YSGG treatment on GIC, caused no harmful surface effects on adjacent restorative materials. SCANNING 38:227-233, 2016. © 2015 Wiley Periodicals, Inc.

Effects of erbium-and chromium-doped yttrium scandium gallium garnet and diode lasers on the surfaces of restorative dental materials: a scanning electron microscope study.

The aim of this study is to evaluate the potential effects of laser irradiation, which is commonly performed in periodontal surgery, on the surfaces of restorative materials. Five different restorative dental materials were used in this study, as follows: (1) Resin composite, (2) poly acid-modified resin composite (compomer), (3) conventional glass ionomer cement (GIC), (4) resin-modified glass ionomer cement (RMGIC), and (5) amalgam. Four cylindrical samples (8 mm diameter, 2 mm height) were prepared for each restorative material. In addition, four freshly extracted, sound human incisors teeth were selected. Two different laser systems commonly used in periodontal surgery were examined in this study: A 810 nm diode laser at a setting of 1 W with continuous-phase laser irradiation for 10 s, and an erbium-and chromium-doped yttrium scandium gallium garnet (Er, Cr: YSGG) laser at settings of 2.5 W, 3.25 W, and 4 W with 25 Hz laser irradiation for 10 s. Scanning electron microscopy (SEM) analysis was performed to evaluate the morphology and surface deformation of the restorative materials and tooth surfaces. According to the SEM images, the Er, Cr: YSGG laser causes irradiation markings that appear as demineralized surfaces on tooth samples. The Er, Cr: YSGG laser also caused deep defects on composite, compomer, and RMGIC surfaces because of its high power, and the ablation was deeper for these samples. High-magnification SEM images of GIC samples showed the melting and combustion effects of the Er, Cr: YSGG laser, which increased as the laser power was increased. In amalgam samples, neither laser left significant harmful effects at the lowest power setting. The diode laser did cause irradiation markings, but they were insignificant compared with those left by the Er, Cr: YSGG laser on the surfaces of the different materials and teeth. Within the limitations of this study, it can be concluded that Er, Cr: YSGG laser irradiation could cause distortions of the surfaces of restorative materials. Diode lasers can be preferred for periodontal surgery.

Profilometric analysis of two composite resins′ surface repolished after tooth brush abrasion with three polishing systems

Aim:To evaluate the effect of three polishing protocols that could be implemented at recall on the surface roughness of two direct esthetic restorative materials.Materials and Methods:Specimens (n = 40) measuring 8 mm (length) × 5 mm (width) × 4 mm (height) were fabricated in an acrylic mold using two light-cured resin-based materials (microfilled composite and microhybrid composite). After photopolymerization, all specimens were finished and polished with one of three polishing protocols (Enhance, One Gloss, and Sof-Lex polishing systems). The average surface roughness of each treated specimen was determined using 3D optical profilometer. Next all specimens were brushed 60,000 times with nylon bristles at 7200 rpm using crosshead brushing device with equal parts of toothpaste and water used as abrasive medium. The surface roughness of each specimen was measured after brushing followed by repolishing with one of three polishing protocols, and then, the final surface roughness values were determined.Results:The data were analyzed using one-way and two-factor analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD). Significant difference (P < 0.05) in surface roughness was observed. Simulated brushing following initial polishing procedure significantly roughened the surface of restorative material (P < 0.05).Conclusion:Polishing protocols can be used to restore a smooth surface on esthetic restorative materials following simulated tooth brushing.

Influence of Self-Etching Adhesive Systems on Restorative Material Surfaces

ABSTRACT This study evaluated the microhardness of restorative materials after the use of self-etching and acid-etching adhesives. Specimens were divided into four groups: Group 1 (CR): Composite resin, Group 2 (GIC): Glass ionomer cement chemically activated, Group 3 (EC): Dual resinous cement, Group 4 (E): Dual resinous cement. Each group was divided into three subgroups, according to the type of adhesive system applied on the surface: Subgroup 1 (C): Control subgroup, Subgroup 2 (XE): Xeno III self-etching adhesive, Subgroup 3 (SB): Single bond acid-etching adhesive. Vickers microhardness analysis was performed on the surfaces and the data were submitted to the two-way ANOVA and the Tukey's test. The means for the material factor: GIC: (35.61)a; CR: (43.54)b; E: (44.65)b; EC: (50.13)c. The means for the adhesive factor: SB: (36.35)a; XE: (38.44)a; C: (55.65)b. All materials tested showed a decrease in surface hardness after application of the adhesive systems, irrespective of the system. The lowest microhardness was shown by GIC and the highest by Enforce Core.

Effect of whitening gels on the surface roughness of restorative materials in situ

Peroxide gels are effective in changing tooth colour but their effect on restorative materials has been poorly studied. The purpose of this investigation was to assess the impact of a commercially available whitening gel containing hydrogen peroxide and a sodium percarbonate formulation on the surface of restorative materials. A total of 12 subjects participated in a double-blinded crossover study. Each wore an intra-oral appliance containing five bovine enamel blocks restored with amalgam, posterior composite, microfilled composite, glass ionomer cement and porcelain. Appliances were worn continuously for 14 days and whitening products were applied twice daily. After 14 days the appliances were removed and values for roughness (R(a)) were obtained using atomic force microscopy. Mean values of R(a) were assessed between baseline and 14 days, and although minor variations were seen, there were no statistically significant differences detected for any material or any whitening product.