In Vitro Study on the Influence of the Buccal Surface Convexity of the Tooth upon Enamel Loss after Bracket Removal.

Polishing after the removal of brackets is the final step in orthodontic treatment. It is simple to perform, though some studies have reported that polishing causes damage to the enamel surface. An in vitro study was made of the influence of the buccal surface convexity of the tooth upon possible enamel loss when the remaining resin and adhesive are removed after bracket decementing using two different polishing modes: a tungsten carbide bur at low and high speeds. The convexity of the buccal surface was quantified in 30 incisors and 30 premolars. A stereoscopic microscope was used to obtain photographs of the profile of the crown, and Image J software was used to calculate convexity by dividing the length of a line from the cementoenamel junction to the incisal margin by another line from the mentioned junction to the maximum convexity of the buccal surface. Brackets were cemented on all the teeth and were decemented 24 h later. In both groups, the residual composite was removed with a tungsten carbide bur at a low speed in one-half of the teeth and at a high speed in the other half. The buccal surface of each tooth was then photographed again, and the convexity was calculated and compared against the baseline value. The difference between the two values were taken to represent the enamel loss. The convexity of the premolars was significantly greater than that of the incisors, but this did not result in greater enamel loss when the same polishing mode was used. However, the tungsten carbide bur at a high speed proved more aggressive, causing significantly greater enamel loss than when used at a low speed.

The Influence of Adhesive Strategy, Type of Dental Composite, and Polishing Time on Marginal Gap Formation in Class I-like Cavities.

Even after more than six decades of dental composite invention (1962), there is still controversial information about the time in which composite restorations should be polished in order to avoid marginal gap formation at the tooth-composite interface. The aim of the present study was to analyze the influence of adhesive strategy, the type of dental composite, and polishing time on marginal gap formation (%MG) at the tooth-composite interface. Class I-like cavities were hybridized with a universal adhesive system (Single Bond Universal) through two strategies: selective enamel etching (SEE) or self-etching mode (SEM). Cavities were filled with two types of dental composites: nanofilled (Z350) or bulk fill (Filtek One Bulk Fill-ONE), and polishing was performed immediately or delayed for 7 days (n = 5). %MG was evaluated by using a 3D laser confocal microscope. As flexural modulus (FM) and degree of conversion (DC%) are determinants of marginal integrity in dental composite restorations, these properties were evaluated for both composites. Data were analyzed by ANOVA and Tukey's HSD test (α = 0.05). Cavities hybridized following the SEE strategy presented lower %MG (p < 0.05). Z350 showed higher %MG than ONE (p < 0.05). There was no difference in %MG between the polishing times when the SEE strategy was used (p > 0.05). Z350 presented higher FM than ONE (p < 0.05). DC% was found to be not significant (p > 0.05). The results suggest that selective enamel etching (SEE) is a better strategy for producing less %MG in composite restorations with enamel margins irrespective of the time in which the restoration is polished.

Spectrophotometric assessment of the color stability of composite resins polished with different techniques.

This study aimed to use spectrophotometry to assess the color stability of composite resins polished with different polishing techniques and scanning electron microscopy (SEM) to evaluate the surface micromorphology of the specimens. In this in vitro experimental study, a total of 96 disc-shaped specimens were fabricated from microfilled (Renamel Microfill, shade SB3) and nanohybrid (Estelite Sigma Quick, shade BW) composite resins in bright white shades (n = 48). Each group was randomized into 1 control and 2 experimental subgroups (n = 16): no polishing (control), polishing with aluminum oxide discs (experimental), or polishing with diamond-impregnated spiral wheels (experimental). In each subgroup, half of the specimens were immersed in a coffee solution and the other half in a tea solution for 48 hours after finishing (control) or polishing (experimental). Spectrophotometry was used to measure the color of the specimens at baseline, after finishing, after polishing (experimental groups only), and after immersion in tea and coffee. The surface micromorphology of a randomly selected specimen from each subgroup was assessed under SEM. The color change (ΔE*) of the specimens between measurements was calculated and analyzed using 1-way, 2-way, and 3-way analyses of variance (ANOVAs) and the Tukey test. Both tea and coffee caused significant color change in the composite resin specimens, with specimens immersed in coffee undergoing significantly greater color change than those immersed in tea (P < 0.001; 2-way ANOVA). The nanohybrid composite specimens polished with polishing discs had a significantly greater color change than nanohybrid specimens polished with spiral wheels (P = 0.041). The Tukey test revealed that there was no overall significant difference between the 2 polishing techniques (P = 0.505), but both of these subgroups exhibited a significantly lower color change than the control group (P < 0.001). In general, SEM did not reveal substantial differences between the 2 polishing techniques, but specimens polished by spiral wheels appeared to have a smoother surface. All polished specimens demonstrated clinically acceptable mean color change values (ΔE* < 3.5). The type of coloring agent had a greater effect on color stability than either the polishing technique or type of composite resin, with coffee causing a greater color change than tea.

Avaliação dos Efeitos da Remoção da Resina Residual e do Polimento na Superfície do Esmalte após Descolagem do Braquete / Evaluation of the Effects of Residual Resin Removal and Polishing on the Enamel Surface after Bracket Debonding

Considerando o uso de brocas para remoção da resina residual após descolagem do braquete e a possibilidade de injúrias à superfície do esmalte após o uso dessas brocas, este trabalho teve como objetivo realizar um estudo experimental, para avaliar a variação do aspecto superficial do esmalte de forma qualitativa, por meio da avaliação com imagens topográficas do esmalte dentário, utilizando-se a Microscopia Eletrônica de Varredura (MEV), a qual permitiu ilustrar e avaliar a superfície do esmalte após a fase de polimento final, realizada por dois métodos: taça de borracha ou escova Robinson. Foram utilizados 25 dentes pré-molares humanos, obtidos a partir de exodontias em pacientes que procuraram voluntariamente o curso de Residência em Cirurgia da Clínica Odontológica Universitária da Universidade Estadual de Londrina. Os dentes foram divididos em quatro grupos: A, B, C e D, contendo 6 dentes cada, de acordo com as brocas utilizadas para a remoção do remanescente adesivo e o polimento escolhido, além de um dente como "controle". Foi avaliada a rugosidade superficial do esmalte após a remoção da resina e a superfície do esmalte após o polimento com as duas opções apresentadas. Os resultados mostraram que, por observação e inspeção, as brocas removeram a resina residual de todos os dentes, porém, causaram riscos e ranhuras, como evidenciado nas imagens em MEV. Concluiu-se que não houve diferença estatística entre os métodos de polimento e que ambos foram importantes para a redução das marcas abrasivas, proporcionando uma superfície mais lisa do esmalte.

Considering the use of specific burs to remove residual resin after bracket debonding and the possibility of injuries to the dental enamel after using these burs, this study aimed to verify the variation in the enamel surface appearance in a qualitative way and evaluation with topographic images of the dental enamel. The use of Scanning Electron Microscopy (SEM) allowed to illustrate and evaluate the enamel surface after the final polishing phase using two methods: rubber cup or Robinson brush. Twenty-five human premolar teeth were obtained from extractions in patients who voluntarily sought the Oral Maxillofacial Surgery Residency at the Dental School from the State University of Londrina; the teeth were divided into four groups A, B, C and D containing 6 teeth each according to the burs used to remove the remaining adhesive and the chosen polishing, in addition to one tooth as a "control". Dental enamel surface roughness was evaluated after resin removal and enamel surface after polishing with the two methods presented. The results showed that by observation and inspection, the burs removed residual resin from all teeth, however, caused scratches and grooves as evidenced in the SEM images. Based on the results, there was no statistical difference between the polishing methods, and both were important for the reduction of abrasive marks and provided a smoother enamel surface.

The Effect of Finishing and Polishing Systems on Surface Roughness and Microbial Adhesion of Bulk Fill Composites: A Systematic Review and Meta-Analysis.

Objectives: This paper presents a systematic review and meta-analysis of the effect of different finishing and polishing (F/P) systems on surface roughness (SR) and microbial adhesion to bulk fill (BF) composites. Materials and Methods: An electronic search of 3 databases (the National Library of Medicine [MEDLINE/PubMed], Scopus, and ScienceDirect) was conducted. Only in vitro studies that evaluated SR and microbial adhesion to BF composites were included. The included studies were individually evaluated for the risk of bias following predetermined criteria. A meta-analysis of the reviewed studies was conducted to compare the SR values of both Filtek Bulk Fill and Tetric EvoCeram Bulk Fill with and without F/P using the Comprehensive Meta-Analysis software. Results: A total of 12 studies fulfilled the inclusion criteria. The meta-analysis showed no significant difference between Filtek Bulk Fill and Tetric EvoCeram Bulk Fill without F/P or after F/P using multi-step systems. Different F/P systems affected the SR values, on the other hand, did not affect microbial adhesion values. Conclusion: Both Filtek Bulk Fill and Tetric EvoCeram Bulk Fill had comparable roughness results. Multi-step systems may be preferable for F/P of BF composites.

Effect of Low-Temperature Degradation, Ph-Cycling and Simulated Tooth Brushing on Surface Roughness, Topography, and Polish Retention of Yttrium-Stabilized Tetragonal Zirconia.

Statement of the Problem: Surface roughness of zirconia is an important parameter that determines the success of zirconia restorations. When zirconia surfaces are left rough, higher susceptibility to hydrothermal aging, plaque accumulation and color changes would occur. Therefore, polish retention of these restorations is considered as a challenge. Purpose: The purpose of this in vitro study was to determine the effect of hydrothermal degradation, pH- cycling, and simulated tooth brushing on surface roughness, topography, and polish retention of an yttrium-stabilized monolithic zirconia. Materials and Method: In this experimental study, 64 specimens of yttria-stabilized tetragonal zirconium oxide (20×4×2mm) were prepared (ZirKonzahn, Steger, Ahrntal). The specimens were wet- polished (standard polishing), and divided into 8 groups (n=8). Four control groups were assessed in non-aged condition while in 4 experimental groups the artificially ageing was done. Different finishing and polishing procedures were performed in 8 groups. The surface roughness values including mean surface roughness (Ra) and mean height of surface roughness (Rz) was measured by a profilometer. The results were analyzed using two-way ANOVA and Tukey's HSD test (α=0.05). One representative specimen of each group was inspected under a scanning electron microscope (SEM) for assessment of surface topography. Results: The effects of surface treatments on Ra (p<.001) and Rz (p<.001) parameters were significant. Ageing had no significant effect on Ra (p=.086) and Rz (p=.067) values. Maximum Ra and Rz parameters were recorded following grinding (p<.001) and minimum values were recorded after glazing, which were significantly lower than the values in grinding group (p<.001). Polishing and glazing diminished the surface roughness (Ra) of ground zirconia similarly (p=.995). Conclusion: Aging had no significant effect on surface roughness of zirconia, irrespective of surface treatment type. Grinding yielded maximum surface roughness. Intra oral polishing yielded a surface roughness comparable to standard polishing and glazing.

Effect of chemical or mechanical finishing/polishing and immersion in staining solutions on the roughness, microhardness, and color stability of CAD-CAM monolithic ceramics.

During the manufacture of ceramic restorations there is an important step of finishing and polishing and the effects of different types of these procedures on the surface characteristics of ceramics are not known for sure. AIM: To evaluate the effects of various surface treatments and immersion in coloring substances on the roughness, microhardness, and color stability of CAD-CAM monolithic ceramics. MATERIALS AND METHOD: The ceramics used were lithium disilicate reinforced with zirconium dioxide (Suprinity), lithium disilicate (E.max) or leucite (Empress). They were subjected to two surface treatments: glazing (group G) (n=20) or mechanical polishing (group P) (n=20). Then they were divided into two subgroups (n=10) to be treated with the staining substance (coffee or water). Roughness, microhardness and color were measured before and after treatment. Data were subjected to analysis of variance and multiple comparisons were performed with Tukey tests at 5% significance level. RESULTS: Roughness was lower in all tested ceramics after polishing than after glazing. Microhardness was the same for polished and glazed E.max, higher in glazed than polished Empress, and higher in polished than glazed Suprinity. Analysis of the effects of glazing and polishing on the individual ceramics showed that the ΔE2000 and ΔWID data of the E.max ceramic subjected to polishing showed greater change. Mechanical polishing is a good option for surface treatment of monolithic ceramics. CONCLUSION: Glazing was inferior and less satisfactory than polishing. Glazing generates changes that can lead to color instability.

Durante a confecção de restaurações cerâmicas existe uma importante etapa dos procedimentos de acabamento e polimento. Os efeitos de diferentes tipos desses procedimentos nas características superficiais das cerâmicas não são conhecidos com certeza. Objetivo: Avaliar os efeitos de vários tratamentos de superfície e imersão em substâncias corantes na rugosidade, microdureza e estabilidade de cor de cerâmicas monolíticas CAD-CAM. Materiais e Métodos: As cerâmicas utilizadas foram dissilicato de lítio reforçado com dióxido de zircônio (Suprinity), dissilicato de lítio (E.max) ou leucita (Empress). Foram submetidos a dois tratamentos de superfície: glazeamento (grupo G) (n=20) ou polimento mecânico (grupo P) (n=20). Em seguida, foram divididos em dois subgrupos (n=10) para serem tratados com a substância corante (café ou água). Rugosidade, microdureza e cor foram medidas antes e após o tratamento. Os dados foram submetidos à análise de variância e as comparações múltiplas foram realizadas com testes de Tukey ao nível de 5% de significância. Resultados: A rugosidade foi menor em todas as cerâmicas testadas após o polimento do que após o glazeamento. A microdureza foi a mesma para o E.max polido e vidrado, maior no Empress vidrado do que no polido, e maior no Suprinity polido do que no vidrado. A análise dos efeitos do esmaltação e polimento nas cerâmicas individuais mostrou que os dados ΔE2000 e ΔWID da cerâmica E.max submetida ao polimento apresentaram maior alteração. O polimento mecânico é uma boa opção para o tratamento superficial de cerâmicas monolíticas. Conclusão: A aplicação do glazing foi inferior e menos satisfatório que o polimento, gerando alterações que podem levar à instabilidade da cor.

Effect of chemical or mechanical finishing/polishing and immersion in staining solutions on the roughness, microhardness, and color stability of CAD-CAM monolithic ceramics / Efeito do acabamento/polimento químico ou mecânico e imersão em soluções manchantes na rugosidade, microdureza e estabilidade da cor em cerâmicas monolíticas CAD-CAM

ABSTRACT During the manufacture of ceramic restorations there is an important step of finishing and polishing and the effects of different types of these procedures on the surface characteristics of ceramics are not known for sure. Aim: To evaluate the effects of various surface treatments and immersion in coloring substances on the roughness, microhardness, and color stability of CAD-CAM monolithic ceramics. Materials and Method: The ceramics used were lithium disilicate reinforced with zirconium dioxide (Suprinity), lithium disilicate (E.max) or leucite (Empress). They were subjected to two surface treatments: glazing (group G) (n=20) or mechanical polishing (group P) (n=20). Then they were divided into two subgroups (n=10) to be treated with the staining substance (coffee or water). Roughness, microhardness and color were measured before and after treatment. Data were subjected to analysis of variance and multiple comparisons were performed with Tukey tests at 5% significance level. Results: Roughness was lower in all tested ceramics after polishing than after glazing. Microhardness was the same for polished and glazed E.max, higher in glazed than polished Empress, and higher in polished than glazed Suprinity. Analysis of the effects of glazing and polishing on the individual ceramics showed that the ΔE2000 and ΔWID data of the E.max ceramic subjected to polishing showed greater change. Mechanical polishing is a good option for surface treatment of monolithic ceramics. Conclusion: Glazing was inferior and less satisfactory than polishing. Glazing generates changes that can lead to color instability.

RESUMO Durante a confecção de restaurações cerâmicas existe uma importante etapa dos procedimentos de acabamento e polimento. Os efeitos de diferentes tipos desses procedimentos nas características superficiais das cerâmicas não são conhecidos com certeza. Objetivo: Avaliar os efeitos de vários tratamentos de superfície e imersão em substâncias corantes na rugosidade, microdureza e estabilidade de cor de cerâmicas monolíticas CAD-CAM. Materiais e Métodos: As cerâmicas utilizadas foram dissilicato de lítio reforçado com dióxido de zircônio (Suprinity), dissilicato de lítio (E.max) ou leucita (Empress). Foram submetidos a dois tratamentos de superfície: glazeamento (grupo G) (n=20) ou polimento mecânico (grupo P) (n=20). Em seguida, foram divididos em dois subgrupos (n=10) para serem tratados com a substância corante (café ou água). Rugosidade, microdureza e cor foram medidas antes e após o tratamento. Os dados foram submetidos à análise de variância e as comparações múltiplas foram realizadas com testes de Tukey ao nível de 5% de significância. Resultados: A rugosidade foi menor em todas as cerâmicas testadas após o polimento do que após o glazeamento. A microdureza foi a mesma para o E.max polido e vidrado, maior no Empress vidrado do que no polido, e maior no Suprinity polido do que no vidrado. A análise dos efeitos do esmaltação e polimento nas cerâmicas individuais mostrou que os dados ΔE2000 e ΔWID da cerâmica E.max submetida ao polimento apresentaram maior alteração. O polimento mecânico é uma boa opção para o tratamento superficial de cerâmicas monolíticas. Conclusão: A aplicação do glazing foi inferior e menos satisfatório que o polimento, gerando alterações que podem levar à instabilidade da cor.

The Evaluation of Different Polishing Techniques' Effects on the Post-operative External Staining of Enamel in Primary and Permanent Tooth.

Objective This study aimed to examine patient complaints on recoloration development after polishing applications in primary and permanent teeth that differed in enamel composition and to determine the ideal polishing method. Methods A total of 30 permanent upper incisors and 30 primary molars were randomly divided into three groups of 10 using three different polishing techniques. Each polishing method (rubber, brush, and air polishing) was applied to the test surface of its own group. Milk and coffee were used in the coloring processes. A spectrophotometer was used for color measurements. Color change (∆E) was calculated between control and test surfaces and between the three measurement points. Results In the primary teeth's test surfaces, the rubber and brush groups were significantly more colored than the air-polishing group, when compared between after polishing and after coloration (p ˂ 0.05). Furthermore, the color difference of the permanent teeth between the initial measurements and after coloration was significantly higher in the rubber group's test surface compared to the air-polished group (p ˂ 0.05). The average ∆E values in both primary and permanent teeth were as follows: rubber > brush > air polishing. Conclusions Compared to rubber or brush polishing, air polishing seems safer to avoid predisposition to postoperative enamel discoloration. Primary teeth are more colored than permanent teeth. The effect of polishing on postoperative coloring should always be considered, and air polishing should be preferred whenever possible.

Evaluation of enamel roughness after orthodontic debonding and clean-up procedures using zirconia, tungsten carbide, and white stone burs: an in vitro study.

BACKGROUND: The main goal of orthodontic debonding is to restore the enamel surface as closely as possible to its pretreatment condition without iatrogenic damage. This study aimed to compare the effects of different adhesive removal burs; zirconia burs, tungsten carbide burs, and white stone burs on enamel surface roughness. MATERIALS AND METHODS: Total sample of 72 extracted premolars was randomly divided into three equal groups (n = 24) depending on the method of adhesive removal: zirconia burs (ZB); tungsten carbide burs (TC); and white stones (WS). The metal brackets were bonded using Transbond XT orthodontic adhesive (3 M Unitek, Monrovia, CA, USA) and debonded after 24 h using a debonding plier, then the ARI was assessed. The adhesive remnants were removed using the different burs and Final polishing was performed using Sof-lex discs and spirals. Thirteen samples from each group were evaluated using a Mitutoyo SJ-210 profilometer to determine average surface roughness (Ra) and three samples from each group were examined under Scanning Electron Microscopy (SEM) to determine EDI score. The evaluations were performed at three time points; before bonding (T0), after adhesive removal (T1) and after polishing (T2) and the time consumed for adhesive removal by burs was recorded in seconds. The data were analyzed statistically by ANOVA, Tukey's test and Kruskal-Wallis H-test. RESULTS: Kruskal-Wallis H-test showed no statistically significant difference of ARI in all studied groups (p = 0.845) and two-way mixed ANOVA revealed that all burs significantly increased surface roughness at T1 compared to T0 (p < 0.001) in all groups with the lowest Ra values were observed in the ZB group, followed by the TC group, and WS group. The fastest procedure was performed with WS, followed by ZB, then TC bur (p < 0.001). After polishing (T2), Ra values showed no significant difference in ZB group (P = 0.428) and TC group (P = 1.000) as compared to T0, while it was significant in WS group (p < 0.001). CONCLUSION: zirconia bur was comparable to tungsten carbide bur and can be considered as alternative to white stone which caused severe enamel damage. The polishing step created smoother surface regardless of the bur used for resin removal.

Ceramic versus Composite Resin Polishing Systems on the Surface Roughness of Milled Leucite-Reinforced Ceramics.

Background and Objective: This study aimed to compare the surface finish of milled leucite-reinforced ceramics polished with ceramic and composite polishing systems based on the manufacturers' recommendations. Materials and Methods: Sixty subtractive computer-aided manufactured (s-CAM) leucite-reinforced glass-ceramic specimens (IPS-Empress-CAD) were assigned into six groups: no polishing, a ceramic polishing kit, and four composite kit groups. The roughness average (Ra) was evaluated in microns using a profilometer, and scanning electron micrographs were obtained for qualitative analysis. A Tukey HSD posthoc test (α = 0.05) was used to determine significant intergroup differences. Results: After surface evaluation of the ceramics, the Ra values of the polishing systems ranked OptraFine (0.41 ± 0.26) < Enhance (1.60 ± 0.54) < Shofu (2.14 ± 0.44) < Astropol (4.05 ± 0.72) < DiaComp (5.66 ± 0.62) < No Polishing (5.66 ± 0.74). Discussion: Composite polishing systems did not provide as smooth surfaces as the ceramic polishing kit for CAD-CAM leucite-reinforced ceramics. Thus, using ceramic polishing systems, polishing leucite ceramics is recommended, whereas composite polishing systems should not be considered as an alternative for use in minimally invasive dentistry.

Influence of polishing systems on surface roughness of four resin composites subjected to thermocycling aging.

Background: Surface smoothness considered to be a significant part of the appearance and success of the restorative materials. The aim of this study was to assess the influence of four different polishing systems on surface roughness of four resin composite materials when subjected to thermocycling. Materials and Methods: This research was designed as a comparative study. Four resin composites were used which are: Nanofill composite (Filtek Supreme XT), nanohybrid composite (Tetric EvoCeram), microfill composite (Renamel Microfill), and microhybrid composite (Filtek Z250). Sixty disk-shaped specimens of each resin composite were prepared then divided into four groups according to the polishing system (n = 15); which were Sof-Lex Spiral, Diatech Shapeguard, Venus Supra, and Astropol. The specimens of each group were polished following the manufactures' instructions, then surface roughness, Ra values in µm were measured initially and after the specimens subjected to thermal cycling. The influence of resin composites, polishing systems, thermocycling, and their interaction effects on surface roughness (Ra mean values) was statistically analyzed mainly by using the repeated measures two-way analysis of variance test, whereas the Bonferroni''s post hoc test was applied for pair-wise comparisons. P ≤ 0.05 was used as the significant level. Results: The results of this study revealed that Filtek Supreme XT recorded significantly the lowest mean surface roughness (Ra) of 0.2533 ± 0.073 µm (P < 0.001). The Sof-Lex Spiral polishing system revealed significantly the lowest mean surface roughness (Ra) of 0.2734 ± 0.0903 µm (P = 0.004). Regardless of composite type and polishing system, there was a statistically significant increase in mean surface roughness values (Ra) in µm after thermocycling (0.2251 ± 0.0496 µm and 0.3506 ± 0.0868 µm, respectively) (P < 0.001). Conclusion: Resin composite type, polishing method, and thermocycling aging significantly affected the surface roughness of composites; Nanofill composite and Sof-Lex Spiral polishing system provided the lowest values of surface roughness which increased after thermocycling.

Surface Roughness in Nanoparticle Resin Composites Subjected to Two Polishing Systems: An In vitro Comparative Study.

Aim: The surface roughness of dental restorations can decrease resin durability, since it leads to its deterioration, color variation, and loss of gloss. Therefore, the aim was to assess the surface roughness of nanoparticle resin composites, subjected to two different polishing systems. Materials and Methods: This longitudinal in vitro experimental study consisted of 32 resin specimens made according to ISO 4049-2019 and divided equally into four groups: A1: Palfique LX5 / Sof-Lex, A2: Palfique LX5 / Super Snap, B1: Filtek Z350 XT / Sof-Lex, and B2: Filtek Z350 XT / Super Snap. The samples were stored in distilled water at 37°C for 24 h. Surface roughness was measured with a digital roughness tester, both before and after the polishing procedure. The data were analyzed with the Student's t-test for related samples, and with the inter-subject ANOVA test with two factors; considering significance at P < 0.05. Results: The surface roughness of Palfique LX5 resin with the Sof-lex system was 0.330 (CI: 0.282-0.378 µm) and 0.170 (CI: 0.087-0.253 µm) before and after polishing, respectively. With the Super Snap system, values of 0.448 (CI: 0.346-0.549 µm) and 0.206 (CI: 0.130-0.282 µm) were obtained before and after polishing, respectively. For the Filtek Z350 XT resin, the surface roughness obtained with the Sof-lex system was 0.353 (CI: 0.278-0.427 µm) and 0.134 (CI: 0.095-0.172 µm) before and after polishing, respectively. With the Super Snap system, values of 0.334 (CI: 0.247-0.421 µm) and 0.171 (CI: 0.122-0.221 µm) were obtained before and after polishing, respectively. Surface roughness did not show significant differences in all groups assessed both before (P = 0.068) and after (P = 0.335) polishing. However, before and after the application of the polishing systems, all groups significantly decreased their surface roughness (P < 0.05). Further, when comparing this decrease among all groups, no significant differences were observed (P = 0.437). Conclusion: The surface roughness of the Filtek Z350 XT and Palfique LX5 nanoparticle resin composites showed no significant differences when using the Sof-lex and Super Snap polishing systems. However, both polishing systems significantly decreased the surface roughness of the nanoparticulated resins, with this decrease being similar in all groups.

In Vitro Color Stability Evaluation of Three Polished and Unpolished Nanohybrid Resin Composites Immersed in a 0.12% Chlorhexidine-Based Mouthwash at Different Times.

The use of chlorhexidine-based mouthwashes on resin composites with rough surfaces can cause discoloration which compromises the esthetic of patients. The present study aimed to evaluate the in vitro color stability of Forma (Ultradent Products, Inc., South Jordan), Tetric N-Ceram (Ivoclar Vivadent, Schaan, Liechtenstein) and Filtek Z350XT (3M, ESPE, St. Paul, MN, USA) resin composites, with and without polishing, after being immersed in a 0.12% chlorhexidine (CHX)-based mouthwash at different times. The present in vitro experimental and longitudinal study used 96 nanohybrid resin composite blocks (Forma, Tetric N-Ceram and Filtek Z350XT) 8 mm in diameter and 2 mm thick, evenly distributed. Each resin composite group was divided into two subgroups (n = 16) with and without polishing and then immersed in a 0.12% CHX-based mouthwash for 7, 14, 21 and 28 days. Color measurements were performed with a calibrated digital spectrophotometer. Nonparametric tests were used to compare independent (Mann-Whitney U and Kruskal-Wallis) and related (Friedman) measures. In addition, the Bonferroni post hoc correction was used considering a significance level of p < 0.05. All polished and unpolished resin composites presented color variation < 3.3 when immersed for up to 14 days in 0.12% CHX-based mouthwash. The polished resin composite with the lowest color variation (ΔE) values over time was Forma, and the one with the highest values was Tetric N-Ceram. When comparing the color variation (ΔE) over time, it was observed that the three resin composites, with and without polishing, presented a significant change (p < 0.001), although these changes in color variation (ΔE) were evident from 14 days between each color acquisition (p < 0.05). The unpolished Forma and Filtek Z350XT resin composites showed significantly more color variation than the same polished ones at all times when immersed in a 0.12% CHX-based mouthwash for 30 s daily. In addition, every 14 days, all three resin composites with and without polishing showed a significant color change, while, every 7 days, color stability was maintained. All the resin composites showed clinically acceptable color stability when exposed for up to 14 days to the above-mentioned mouthwash.

Enamel Evaluation after Debonding of Fixed Retention and Polishing Treatment with Three Different Methods.

Lack of standardization of the retention phase has led to many studies of stability of movements and characteristic of retainers, disregarding the enamel repercussions of fixed retention on this phase. This study aimed to analyze different methods of enamel polishing after detachment of orthodontic retainers. Forty-five healthy premolars were divided into three groups according to the polishing bur after debonding, and four specimens without intervention were used as control. A 0.038 × 0.015 inches gold chain was bonded between the premolars and then removed. The adhesive remnant was removed with three types of burs according to the study groups (Group 1: white stone at high speed; Group 2: high-speed handpiece with a 30-blade tungsten carbide bur; Group 3: low-speed handpiece and a 30-blade tungsten bur). After debonding and polishing, all samples were analyzed with a confocal microscopy on surface roughness parameters: Sa: Arithmetic mean of the height of the surface. Rq: Square mean of the height of the surface and Sz: Maximum surface height. Mechanical tests were carried out to determine the bonding stress of the retention adhered to the teeth using an electromechanical testing machine. The adhesion stress was 8.23 MPa (±0.87). The quality of the refinement of the enamel after debonding is essential in order to preserve its integrity. The use of the 30-blade tungsten carbide bur provides a smooth enamel surface after polishing.

Estabilidad de Color de Tres Resinas Nanohíbridas en Relación al Tipo Pulido Realizado

El color de las restauraciones se considera una de las características más exigidas por los pacientes, cuyo éxito final dependerá de mantenerse en el tiempo, sin sufrir alteraciones. El objetivo de este estudio fue determinar la estabilidad de color que experimentan las resinas al ser sumergidas en una sustancia pigmentante en función al factor tiempo y al tipo de pulido final realizado. Estudio experimental in vitro de tres resinas de nanopartículas: Filtek Z-350 XT® (3M), Brillant NG® (Coltene), Tetric N-Ceram® (Vivadent) donde se comparó la estabilidad de color al ser sumergidas en café. Se confeccionaron 120 discos de resinas (color esmalte A3) divididos posteriormente en dos grupos: Grupo 1 protocolo habitual de pulido Grupo 2: protocolo habitual más sellador fotocurable Biscover® (Bisco). Las muestras fueron almacenadas en agua destilada en estufa a 37° durante 24 hs para su hidratación. Se registró el color utilizando el colorímetro Kónica Minolta®. Posteriormente se sumergieron las muestras en café, y se tomó nuevamente el color a las 24 hs y a los 7 días. Los datos fueron analizados estadísticamente mediante análisis de varianza y test de compación de Tukey. Se observó que la resina que más se pigmentó en el grupo 1 correspondió a la resina Filteck Z-350 con DE: 4,68 a las 24 hs y DE: 5,53 a los 7 días. Al analizar el grupo 2 las tres resinas se mantuvieron en valores bajos de DE: 0,96 a 1,42 en ambos períodos. Al sumergir las resinas en una sustancia pigmentante, la alteración del color se va produciendo en función del tiempo. Sin embargo, el uso complementario de un sellador fotocurable como pulido mejora significativamente la estabilidad de color en estos materiales, factores que el clínico debe tener en cuenta para lograr el éxito de sus restauraciones.

The color of the restorations is considered one of the characteristics most demanded by patients, whose final success will depend on being maintained over time, without undergoing alterations. The objective of this study was to determine the color variations experienced by reinforced resins when immersed in a pigmenting substance as a function of the time factor and the type of final polishing performed. In vitro experimental study of three nanoparticle resins: Filtek Z-350 XT® (3M), Brillant NG® (Coltene), Tetric N-Ceram® (Vivadent) where color stability was compared when immersed in coffee. 120 Discs of resins (enamel color A3) were made and subsequently divided into two groups: Group 1 usual polishing protocol Group 2: usual protocol plus Biscover® (Bisco) light-curing sealer. The samples were stored in distilled water in an oven at 37 ° for 24 hours for hydration. Color was recorded using the Konica Minolta® colorimeter. Subsequently, the samples were immersed in coffee, and the color was taken again at 24 hours and 7 days. Data were statistically analyzed using analysis of variance and Tukey's comparison test. It was observed that the most pigmented resin in group 1 corresponded to the Filteck Z-350 resin with DE: 4.68 at 24 hours and DE: 5.53 at 7 days. When analyzing group 2, the three resins maintained low DE values: 0.96 to 1.42 in both periods. By immersing the resins in a pigmenting substance, the change in color occurs over time. However, the complementary use of a light-curing sealer such as polishing significantly improves color stability in these materials, factors that the clinician must take into account to achieve the success of their restorations.

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.

Sistemas de pulido para restauraciones cerámicas. Revisión de la literatura / Polishing systems for ceramic restorations. Literature review

El pulido es un paso de suma importancia en el flujo de trabajo de las restauraciones cerámicas, después de realizado un ajuste con puntas o piedras diamantadas, ya que disminuye la rugosidad de las superficies tratadas. Esto repercute positivamente en las propiedades mecánicas y ópticas del material. Sin embargo, la poca literatura disponible acerca de este procedimiento hace que sea pasado por alto. Debido a esto, el presente articulo tuvo como objetivo realizar una revisión bibliográfica sobre los diferentes protocolos de pulido para las diversas restauraciones cerámicas de mayor uso: Feldespática, disilicato de litio y zirconia en sus diferentes presentaciones. Se describen aspectos relevantes sobre el pulido mecánico, la rugosidad superficial y los sistemas de pulido actuales para cerámicas.

Polishing is an extremely important step in the workflow of ceramic restorations, after adjustment with diamond burs or stones, as it reduces the roughness of the treated surfaces. This has a positive impact on the mechanical and optical properties of the material; however, the limited literature available about this procedure makes it to be overlooked. Therefore, the aim of this article was to review the literature on the different polishing protocols for the most used ceramic restorations: Feldspathic, lithium disilicate and zirconia ceramics. Relevant aspects on mechanical polishing, surface roughness and current polishing systems for ceramics are described.

Evaluation of different composite resin finishing and polishing protocols by confocal laser scan microscopy

Aim This study aimed to analyze the influence of finishing and polishing (F/P) protocols on resin surface through roughness (Ra) values and laser scan microscopy observations. Methods Forty-eight (n=48) resin specimens were sorted into four groups (n=12), according to the type of resin used: Filtek Z250 (Z250), Filtek Z350 (Z350), Filtek One Bulk Fill (BF), Filtek P60 (P60). The specimens were sorted into six groups according to the type of F/P system used (n=2/group): Control group, Diamond bur (KG Sorensen), Soflex Pop-On Discs (3M ESPE), Soflex Spiral (3M ESPE), Dura Gloss (American Burs), and Praxis (TDV). Results The highest roughness values (Ra) were attributed to BF group for all F/P systems, except for the Soft-Lex PopOn discs. The Soft-Lex PopOn, Spiral, and Praxis discs presented a better performance for the surface treatment of the tested composite resins. Regardless of the restorative material, the use of diamond bur or single-step abrasive rubber (Dura Gloss) were associated with the highest Ra values. Conclusion The effect of F/P systems on Ra is material-dependent and instrument or system-dependent.

Knowledge and practice of dentists in processing polishing points: A cross-sectional study.

BACKGROUND: Adequately processing polishing points used to polish composite resin restorations is necessary for microbiological control in dentistry, but there is no specific protocol to guide professionals. Therefore, this study aimed to assess the knowledge and practice of dentists in processing these instruments. METHODS: This cross-sectional observational study included the application of an online questionnaire via Google Forms and social media promotion. The study evaluated the association of field of activity, time since graduation, age, and sex of professionals with processing practice. The statistical analysis was performed with absolute and relative frequencies and logistic and Poisson regressions at a 5% significance level. RESULTS: Overall, 473 questionnaires were analyzed. A rate of 51% of professionals reported using inadequate processing methods, and almost 68% claimed to have good knowledge of the topic. Both regression analyses were significantly associated, showing a direct effect of age and time since graduation on adequate processing practices. CONCLUSIONS: Although most professionals reported understanding the processing of polishing points, they do not perform it most adequately. CLINICAL SIGNIFICANCE: An expressive number of dentists process polishing points improperly. The topic is significant for representing a semi-critical instrument extensively used in esthetic restorations.