In vitro comparison of one-step, two-step, and three-step polishing systems on the surface roughness and gloss of different resin composites.

OBJECTIVES: This laboratory study evaluated the effect of three polishing systems on the surface roughness and gloss of resin composites. MATERIALS AND METHODS: Thirty specimens (6 mm Ø × 8 mm) were fabricated from each of three resin composites: Z 350 XT (nanofill), Harmonize (nanohybrid), and Estelite Omega (supranonofill). All specimens were photopolymerized using a multi-peak LED curing unit (VALO-Standard mode), having a exitance irradiance of approximately 1000 mW/cm2 against a polyester strip (PS). 2 mm was then removed from the irradiated end (finished) using #320 abrasive paper (F). Specimens were then randomly polished (P) using a one-step (1S) (OneGloss), two-step (2S) (EVE Diacomp Twist Basic CA), or 3-step (3S) (Astropol P) system (n = 10). For PS, F, and P groups, surface roughness (Ra) was measured using a surface roughness tester, and surface gloss was measured with a glossmeter. For each specimen, the percent recovery to the PS value (%R) of surface roughness and surface gloss were calculated. Data were analyzed using two-way ANOVA, followed by Tukey's test. Surface roughness and gloss values were submitted to Pearson's correlation test (α = 0.05). All statistical testing was performed using a pre-set alpha of 0.05. RESULTS: The interaction term [resin composite × polishing system] was significant for both surface roughness (p = 0.001) and gloss (p = 0.0001). For all resin composites, the 2S and 3S systems provided a higher %R of surface roughness and gloss compared to those of the 1S system. There was a negative correlation between surface roughness and gloss, but only a few combinations showed strong correlations. CONCLUSIONS: The 2S and 3S polishing systems provided surfaces having greater smoothness and gloss compared to the 1S system. The ability to recover surface roughness and gloss was dependent on type of resin composite filler classification. CLINICAL SIGNIFICANCE: The 3S and 2S polishing systems were more effective in achieving PS values than was the 1S system for all tested resin composites. However, individual polishing systems performed differently depending on type of resin composite.

Do bioactive materials show greater retention rates in restoring permanent teeth than non-bioactive materials? A systematic review and network meta-analysis of randomized controlled trials.

OBJECTIVES: To answer the following research question: does the clinical evaluation of restorations on permanent teeth with bioactive materials show greater retention rates than those with non-bioactive materials? MATERIALS AND METHODS: A search strategy was used in the following databases: MEDLINE via PubMed, Scopus, Web of Science, LILACS, BBO, Embase, The Cochrane Library, and OpenGrey. Randomized controlled trials (RCTs), with a minimum of 2-year follow-up and evaluating at least one bioactive material in permanent teeth were included. Risk of bias was detected according to the Cochrane Collaboration tool for assessing the risk of bias (RoB 2.0), and network meta-analysis was performed using a random-effects Bayesian-mixed treatment comparison model. RESULTS: Twenty-seven studies were included. The success of the restorations was assessed using modified USPHS system in 24 studies and the FDI criteria in 3 studies. Network meta-analysis revealed three networks based on restoration preparations. Resin composites were ranked with higher SUCRA values, indicating a greater likelihood of being the preferred treatment for class I, II, and III restorations. In class V, resin-modified glass ionomer cement was ranked with the highest value. CONCLUSION: Bioactive restorative materials showed similar good clinical performance in terms of retention similarly to conventional resin composites. CLINICAL SIGNIFICANCE: The findings must be interpreted with caution because many RCT on restorative materials aim to verify the equivalence of new materials over the gold standard material rather than their superiority. The present systematic review also suggests that new RCT with longer follow-up periods are necessary.

Injectable Composite Resin Technique: An Alternative for Anterior Esthetic Restorations - Case Report / Técnica de Resina Compuesta Inyectable: Una Alternativa para Restauraciones Estéticas Anteriores - Reporte de Caso

This article aims to describe a clinical case of the use of the injectable restorative technique with composite resin in a patient with an esthetic complaint in the anterior teeth. Producing direct restorations in anterior teeth when performed with composite resin demands a long clinical time. Results often depend on the operator's ability to reproduce proper form, function, and esthetics. Lately, the versatility of composite resins has increased. As this material evolved, new techniques were introduced to simplify the restorative process and save time. The restorative technique with injectable fluid composite resin, in addition to delivering faster and with a certain ease, is capable of increasing the predictability of treatment results. However, it is known that flowable resins have lower wear resistance and color stability compared to conventional resins. Thus, a version of this material with a higher filler content in its composition was introduced to the market, to improve wear resistance and gloss retention. Long-term studies evaluating the use of low-viscosity resins are needed. The injectable technique can accurately reproduce the morphology obtained in the wax-up of the case, generating a satisfactory esthetic and functional result. Despite simplifying the fabrication of restorations when compared to the conventional technique, it is still necessary for the operator to have some experience and aptitude. The clinical time for the production of restorations has been considerably reduced. The material showed good flow, shine, and polish in the immediate result. However, the finishing and polishing of the restorations required a longer clinical period than usual and in the short- term follow-up, flaws in the gingival margins and a new finishing and polishing procedure were necessary. Therefore, the technique described in this article can be considered a restorative alternative, but it is still not able to replace the tradit ional method of making previous esthetic restorations.

Este artículo tiene como objetivo describir un caso clínico del uso de la técnica restauradora inyectable con resina compuesta en un paciente con una queja estética en los dientes anteriores. Producir restauraciones directas en dientes anteriores cuando se realizan con resina compuesta demanda un largo tiempo clínico. Los resultados a menudo dependen de la capacidad del operador para reproducir la forma, la función y la estética adecuadas. Últimamente, la versatilidad de las resinas compuestas ha aumentado. A medida que este material evolucionó, se introdujeron nuevas técnicas para simplificar el proceso de restauración y ahorrar tiempo. La técnica restauradora con resina compuesta fluida inyectable, además de una entrega más rápida y segura, es capaz de aumentar la previsibilidad de los resultados del tratamiento. Sin embargo, se sabe que las resinas fluidas tienen menor resistencia al desgaste y estabilidad del color en comparación con las resinas convencionales. Así, se introdujo en el mercado una versión de este material con un mayor contenido de relleno en su composición, con el objetivo de mejorar la resistencia al desgaste y la retención del brillo. Se necesitan estudios a largo plazo que evalúen el uso de resinas de baja viscosidad. La técnica inyectable es capaz de reproducir fielmente la morfología obtenida en el encerado del caso, generando un resultado estético y funcional satisfactorio. A pesar de simplificar la fabricación de restauraciones en comparación con la técnica convencional, todavía es necesario que el operador tenga cierta experiencia y aptitud. El tiempo clínico para la producción de restauraciones se ha reducido considerablemente. El material mostró buena fluidez, brillo y pulido en el resultado inmediato. Sin embargo, el acabado y pulido de las restauraciones requirió de un período de tiempo clínico más largo de lo habitual y en el seguimiento a corto plazo, fueron necesarios defectos en los márgenes gingivales y un nuevo procedimiento de acabado y pulido. Por lo tanto, la técnica descrita en este artículo puede considerarse una alternativa restauradora, pero aún no es capaz de reemplazar el método tradicional de realizar restauraciones estéticas previas.

Efficacy of bioactive materials in preventing Streptococcus mutans-induced caries on enamel and dentine.

The study investigated the ability of bioactive materials used to restore enamel and dentine specimens to prevent caries. Enamel (n = 50) and dentine (n = 50) specimens were obtained from bovine incisors, prepared, and randomly allocated to one of five groups according to the restorative treatment: alkasite without adhesive system; alkasite with adhesive system; high viscosity glass ionomer cement; resin composite; no restoration; negative control group. Specimens were restored, exposed to a thermal cycling aging protocol, sterilized, and exposed to a cariogenic challenge induced by Streptococcus mutans and then submitted to surface and subsurface microhardness tests and polarized light microscopy to verify the caries lesion development in enamel or dentine surrounding the restorative materials. Data were analyzed using one-way ANOVA. In enamel and dentine, glass ionomer cement, alkasite without and with adhesive system presented a lower percentage surface microhardness loss than resin composite and negative control. Enamel subsurface microhardness presented no statistically significant differences between glass ionomer cement, alkasite without and with adhesive system. Glass ionomer cement also did not present statistically significant differences from resin composite and the negative control. In dentine, glass ionomer cement showed the highest subsurface microhardness values. In conclusion, bioactive restorative materials provide greater protection to enamel and dentine against surface caries development than resin composite.

An 8-year follow-up of resin infiltration on anterior white spot lesions.

White spot lesions (WSLs) are sites of enamel surface and subsurface demineralization that increases tissue porosity and affects the teeth appearance. The resin infiltration technique proved to be a valid alternative to arrest caries lesion progression and to masking a color change in noncavitated WSLs. Thus, this study aims to report a clinical case of anterior WSLs treated with resin infiltration technique with an 8-year follow-up. The resin infiltration protocol was performed in an 18-year-old female patient presenting WSLs on the maxillary right lateral incisor, left central incisor, and left canine. The protocol followed the manufacturer's recommendations. The patient reported satisfaction with the smile appearance, at the end of the appointment. Infiltrated areas remained unchanged after an 8-year follow-up, showing an acceptable result for the patient's esthetic desires. After 8 years of evaluation, the resin infiltration technique proved to be a resistant and reliable alternative in preventing caries progression and in color masking WSLs.

Effects of lesion size on the 30-month clinical performance of restorations with bulk fill and a regular nanofilled resin composite in noncarious cervical lesions.

OBJECTIVE: The aim of this double-blind, randomized trial was to evaluate the influence of the occlusogingival distance (OGD) in noncarious cervical lesions (NCCLs) on the clinical performance of a regular bulk-fill resin composite and a regular nanofilled resin composite. MATERIALS AND METHODS: One hundred and forty NCCLs in 77 participants were randomly divided into four groups (n = 35), according to OGD (1.5 mm ± 10% or 3 mm ± 10%) and resin composites (Filtek Bulk Fill Posterior [B] or Filtek Z350 XT [C]), namely: 1.5 mm-B, 1.5 mm-C, 3 mm-B, and 3 mm-C. The restorations were bonded using a two-step self-etch adhesive (Clearfil SE Bond), applied following the manufacturer's instructions. Restorations were polished 1 week after placement. Two experienced and calibrated examiners evaluated the restorations using modified US Public Health Service criteria at baseline (7 days) and after 6, 12, 18, 24, and 30 months. Statistical analyses were carried out using Kruskal-Wallis, Friedman's repeated measures analysis of variance, and the Wilcoxon signed rank test (α = 0.05). RESULTS: After 30 months, the recall rate was 94.2%. Eight restorations were lost (3 for 1.5 mm-C, 2 for 1.5 mm-B, 1 for 3 mm-C, and 2 for 3 mm-B). All groups resulted in a significantly worse marginal discoloration and surface texture at 30 months in comparison with the baseline (1 week). No significant difference was found for the other parameters. CONCLUSION: The restorations performed with both resin composites produced clinically acceptable restorations. The OGD of NCCLs did not influence the clinical performance of restorations. CLINICAL SIGNIFICANCE: The OGD of NCCLs did not have a significant effect on the clinical performance of a regular bulk-fill and nanofilled restorations. Both materials showed a very good performance on 30-month evaluation.

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.

Multiple gingival recessions associated with non-carious cervical lesions treated by partial restoration and modified coronally advanced flap with either connective tissue graft or xenogeneic acellular dermal matrix: A randomized clinical trial.

BACKGROUND: This study aimed to compare a connective tissue graft (CTG) to a (porcine) xenogeneic acellular dermal matrix (XDM), both associated with modified coronally advanced flap (MCAF) and partial resin composite restoration to treat multiple combined defects (CDs). METHODS: Seventy-eight defects in 38 patients presenting multiple combined defects, that is, gingival recession associated with non-carious cervical lesions, were treated by partial resin composite restoration (apical margin up to 1 mm of the estimated cement-enamel junction) and MCAF along with CTG or XDM. After 6 months, the groups were compared with regard to clinical, patient-centered, and esthetic outcomes. RESULTS: CD coverage was 72.9% for CTG versus 50.7% for XDM (P < 0.001). Recession reduction was 2.3 mm for CTG versus 1.5 mm for XDM (P < 0.001). CTG resulted in a greater increase in keratinized tissue width (CTG: 0.96 mm vs. XDM: 0.3 mm, P = 0.04) and gingival thickness (CTG: 0.9 mm vs. XDM: 0.3 mm, P < 0.001). Both treatments successfully reduced dentin hypersensitivity and increased esthetics satisfaction, with no statistically significant intergroup differences. Moreover, XDM patients experienced a shorter surgery duration (CTG: 57.2 min vs. XDM: 37.4 min, P < 0.001) and less time to no pain (visual analog scale  =  0; CTG: 6.5 days vs. XDM: 3.5 days, P = 0.04). CONCLUSION: CTG resulted in significantly greater root coverage and increased keratinized tissue width compared to XDM for treating multiple partially restored CDs. However, increased root coverage at the CTG sites was accounted for by increased probing depth compared to the XDM sites.

Evaluation of a novel restorative protocol to treat non-carious cervical lesion associated with gingival recession: a 2-year follow-up randomized clinical trial.

OBJECTIVE: To compare 2 different resin composites and 2 adhesive systems used in a new restorative protocol (partial restoration) to treat non-carious cervical lesions associated with gingival recession type 1 (RT1). MATERIAL AND METHODS: Eighty combined defects (CDs) were treated with a partial restoration and periodontal plastic surgery for root coverage. The CDs were randomly assigned to one of the following groups: NP + TE (n = 20), nanofilled composite and 2-step total-etch adhesive system; NP + UA (n = 20), nanofilled composite and universal adhesive system; MH + TE (n = 20), microhybrid composite and 2-step total-etch adhesive; MH + UA (n = 20), microhybrid composite and universal adhesive. Restorations were assessed using the United States Public Health Service (USPHS) criteria at 1 week (baseline) and 6, 12, and 24 months. Survival rate, periodontal parameters, dentin hypersensitivity (DH), and aesthetics were also evaluated. RESULTS: After 24 months, only the MH + TE group did not lose any restoration, with no significant differences between groups. For surface roughness parameter, MH presented 83.3% of the restorations scoring Bravo, whereas NP presented 48.5% of the restorations scoring Bravo. All groups presented restorations with marginal discoloration. All periodontal parameters behaved similarly, regardless of the restorative material. All groups presented significant reductions of dentin hypersensitivity and improved aesthetic perceptions (p < 0.05). CONCLUSION: Both resin composites and adhesives tested can be combined for partial restorations to treat CDs. CLINICAL RELEVANCE: This new restorative-surgical protocol to treat CDs presents satisfactory outcomes. The partial restorations can be successfully executed with both combinations of adhesives and resin composites evaluated in this investigation. TRN : ClinicalTrial.gov: NCT03215615; registration date July 12, 2017.

Influence of different intraradicular chemical pretreatments on the bond strength of adhesive interface between dentine and fiber post cements: A systematic review and network meta-analysis.

Systematic review and network meta-analyses were performed to answer the question: Do intraradicular chemical pretreatments affect the bond strength of the adhesive interface between dentine and fiber post cements? A literature search was performed in PubMed, Scopus, Web of Science, LILACS, BBO, and Cochrane Library in October 2018 (updated September 2021). In vitro studies that compared the bond strength assessed by push-out tests following at least two dentine chemical treatments prior to fiber post cementation were included. Risk of bias was evaluated. A random-effects Bayesian-mixed treatment comparison model was used to compare push-out bond strength of different chemical pretreatments. SUCRA (surface area under the cumulative ranking) analysis was performed to rank the pretreatments. After removing duplicates and screening titles and abstracts, 61 studies remained. SUCRA analysis showed that the best bond strength values for self-etch, etch-and-rinse, and self-adhesive cements were ethyl acetate (SUCRA: 99.8%), low concentration NaOCl (SUCRA: 83.4%), and grape seed extract (SUCRA: 97.6%), respectively. According to the SUCRA rankings, ethanol was in a good position for all adhesive strategies (SUCRA: 78.6%). The use of chemical pretreatments in intraradicular dentine of endodontically treated teeth depends on the adhesive and cementation strategy. The pretreatment generally associated with the highest bond strength was ethanol.

Influence of knowledge on Brazilian student's perception of life and clinical classes during COVID-19.

BACKGROUND: The current pandemic associated with SARS-CoV-2 has negatively influenced several activities, including teaching in Operative Dentistry. The aim of this study was to evaluate the influence of knowledge in Operative Dentistry on undergraduate students' perception related to personal life and return to clinical practices classes during pandemic. MATERIALS AND METHODS: The present research was a cross-sectional, observational, and qualitative survey. The 16-item based questionnaire was sent to undergraduate students in 2020, which were divided into two groups, according to the Operative Dentistry knowledge: G1-not started clinical practice; G2-already started or completed clinical practice. Questions were focused on the impact of the pandemic in relation to their personal lives and return to clinical practice classes. Chi-square association test was performed using the SigmaPlot 12.0 software (P ≤ 0.05). RESULTS: The response rate was 55.5% for G1 and 44.4% for G2. Regarding the questions related to personal life, G1 demonstrated higher percentages of fear of contracting the virus during theoretical classes. Same observations were found when students answered about their fear of contracting coronavirus during the clinical practice classes. However, G2 presented the highest agreement responses for the preparedness feeling to return to theoretical classroom, clinical practice classes, and the possibility of applying online learning. CONCLUSIONS: In general, students' knowledge had little influence on perception of personal life. However, students who have more knowledge in operative dentistry presented more security about returning to clinical classes.

Effect of fluoride, chlorhexidine or Nd:YAG on the progression of root dentin demineralization after removal of the demineralized organic matrix.

OBJECTIVES: Quantification of collagen degradation is an important parameter to evaluate dentin caries for preventive aid.. Evaluate preventive methods against root collagen degradation by the hydroxyproline assay (HYP) and microradiography technique (MRT). METHODOLOGY: Five bovine root dentin blocks were obtained and subjected to an artificial demineralization process by acetate buffer (pH 5) to induce carious lesion formation. Samples were subjected to the following therapeutic treatments: 1) 0.12% chlorhexidine for 1 min, 2) 2% fluoride for 1 min, 3) Nd:YAG Laser (400 µm diameter optical fiber, 10 Hz frequency, 60 mJ/pulse energy, 48 J/cm2 energy density, in noncontact mode for 10 s), 4) deionized water (control) for 1 min, 5) MRT control group (without treatment and removal of collagen). Samples were exposed to degradation by a collagenase enzyme for five days. The enzyme solution was collected, by colorimetry in a spectrophotometer, from the collagen matrix for the hydroxyproline release analysis. The same samples were subjected to an additional two days of demineralization to induce the progression of mineral loss. Samples were analyzed by MRT for the visualization of their degraded areas (estimation of lesion depth and mineral loss). ANOVA was applied to compare hydroxyproline release rates. MRT data were subjected to the Kruskal-Wallis test, followed by the Dunn's test. Comparisons between the initial five-day and the subsequent two-day demineralization processes were performed by repeated t-test or Wilcoxon (p<0.05) measurements. RESULTS: The amount of HYP released from the dentin samples failed to show significant differences among the groups (p=0.09). Fluoride and chlorhexidine were able to interact with the samples, reducing the progression of dentin caries after removal of the demineralized organic matrix. CHX was the only treatment able to show significant lower lesion depth than the negative control. CONCLUSION: Chlorhexidine and fluoride were effective in reducing root caries progression.

Prevalence of White Spot Caries Lesions in Primary Teeth in Preschool Children: Systematic Review and Meta-analysis.

BACKGROUND: The first clinically detectable stage of caries lesion is a non-cavitated white spot lesion (WSL). The detection of early stages of caries lesions allows non-invasive management by fluoride usage, oral hygiene and diet control. There is a lack of information in the literature regarding the prevalence of these caries lesions in preschool children, which is important especially for public health strategies. OBJECTIVE: The aim of this study was to conduct a systematic review with meta-analysis to verify the WSLs prevalence in primary teeth of preschool children. METHODS: A literature search with MEDLINE/PubMed, Scopus, Web of Science, and Open Gray databases was conducted. Included studies fulfilled the eligibility criteria. Meta-analyses were performed using random effects model, for prevalence of pooled WSLs and subgroups analyses. RESULTS: The search strategy identified 4922 potentially relevant articles, with final inclusion of 16 studies. The pooled prevalence of WSLs in primary teeth was 14.0% (95% CI: 8.0-24.0), without publication bias (p=0.2668). For subgroup analyses, an increase in WSLs prevalence for children of low-income economy (24.0%; 95% CI: 20.0-28.0), for age >31 months (22.0%; 95% CI: 12.0-37.0), for validated visual criteria assessment (20.0%; 95% CI: 11.0-33.0), and for tactile assessment with ball-ended probe (26.0%; 95% CI: 11-50.0) were detected. CONCLUSION: It is suggested that the prevalence of WSLs in primary teeth of preschool children increases in countries with low income economy, with age greater than 31 months or texture assessment with visual validated criteria or ball-ended probe. PROSPERO Registration: Protocol number #CDR42017078434.

Effect of intraradicular fiber post on the fracture resistance of endodontically treated and restored anterior teeth: A systematic review and meta-analysis.

STATEMENT OF PROBLEM: A fiber post is indicated when there is a significant loss of tooth structure and additional support for the restoration is needed. However, whether the use of a glass fiber post affects the fracture susceptibility of the restored anterior teeth is unknown. PURPOSE: The purpose of this systematic review and meta-analysis was to evaluate the fracture resistance of endodontically treated and restored anterior teeth and to answer the research question, "Does the use of a fiber post influence the fracture resistance of endodontically treated and restored anterior teeth compared with alternative restorative treatments?" MATERIAL AND METHODS: A search was performed in PubMed, Scopus, Web of Science, LILACS, BBO, Cochrane Library, and Embase databases without date and/or language restrictions (updated in July, 2020). In vitro studies comparing the fracture strength of endodontically treated and restored anterior teeth with and without fiber posts were included. The risk of bias was evaluated by using the previous meta-analyses of in vitro studies. The results were presented as standardized mean difference with a 95% confidence interval. Statistical heterogeneity of treatment effects between studies was assessed using the Cochran Q test and the I2 inconsistency test, and values greater than 50% were considered indicative of substantial heterogeneity. RESULTS: After the removal of duplicates and title and abstract screening, 31 studies remained. Seventeen were considered low risk of bias, 10 were medium risk of bias, and 4 were high risk of bias. Meta-analysis comparing control and experimental groups favored the use of a fiber post in endodontically treated teeth with some types of restoration to improve fracture resistance (standardized mean difference= 0.5 [0.08; 0.92]); a glass fiber post was also favored (standardized mean difference=0.92 [0.43; 1.42]); for veneer preparations and teeth with cervical cavities, a fiber post increases the fracture strength (standardized mean difference= 0.74 [0.01; 1.47]; 1.18 [0.35; 2.02], respectively). CONCLUSIONS: The use of glass fiber posts increases the fracture resistance of endodontically treated and restored teeth.

Single gingival recession associated with non-carious cervical lesion treated by partial restoration and coronally advanced flap with or without xenogenous collagen matrix: A randomized clinical trial evaluating the coverage procedures and restorative protocol.

BACKGROUND: Evaluate the use of collagen matrix (CM) as adjunctive to coronally advanced flap (CAF versus CAF + CM) to treat gingival recession (GR) associated with non-carious cervical lesion-combined defects (CDs). METHODS: Sixty-two patients presenting 62 CDs (RT1 GR and non-carious cervical lesion (NCCLs) were randomly allocated to either CAF group (n = 31): partial restoration of the NCCL and CAF; or to CAF + CM group (n = 31): partial restoration of the NCCL and CAF associated with CM. Clinical, esthetic, patient-centered outcomes, and restorative parameters were assessed. RESULTS: After 12 months, CD coverage were 55.2% for CAF and 54.4% for CAF + CM (P = 0.8). Recession reduction were 1.9 ± 0.8 mm for CAF and 2.0 ± 0.7 mm for CAF + CM (P = 0.6). CAF+CM resulted in higher increase in keratinized tissue (KT) width (CAF: 0.3 ± 0.7 mm; CAF + CM: 0.9 ± 0.8 mm; P = 0.004) and KT thickness gain (CAF: 0.1 ± 0.3 mm; CAF + CM: 0.7 ± 0.2 mm; P = 0.001). Both treatments presented low postoperative pain and resulted in esthetics improvements. In addition, no restoration was lost, 27.4% showed a reduction of the superficial polishing, and 8% showed marginal staining, but still clinically acceptable. CONCLUSION: Partial resin composite restoration (with the apical limit up to 1 mm of the estimated CEJ) and CAF alone or combined with CM are suitable for treating CDs. The use of CM provided additional benefits in terms of KT width and thickness gain. (NCT03341598).

Fatigue behavior and stress distribution of molars restored with MOD inlays with and without deep margin elevation.

OBJECTIVES: This study evaluated the effect of deep margin elevation (DME) and restorative materials (leucite-reinforced glass-ceramics [C] vs. indirect resin composite [R]) on the fatigue behavior and stress distribution of maxillary molars with 2-mm deep proximal margins restored with MOD inlay. METHODS: Fifty-two extracted human third molars were randomly assigned into four groups (n = 13): C; DME + C; R; and DME + R. Inlays were fabricated in CAD-CAM and bonded to all teeth. The fatigue behavior was assessed with the stepwise stress test (10,000 cycles/step; step = 50 N; 20 Hz; initial load = 200 N). Fatigue failure loads and the number of cycles were analyzed with 2-way ANOVA and Tukey's test (p < 0.05) and Kaplan-Meier survival plots. The stress distribution was assessed with finite element analysis. The models were considered isotropic, linear, and homogeneous, and presented bonded contacts. A tripod axial load (400 N) was applied to the occlusal surface. The stress distribution was analyzed with the maximum principal stress criterion. RESULTS: For fatigue, there was no difference for DME factor (p > 0.05). For the material factor, the load and number of cycles for failure were statistically higher in the R groups (p < 0.05). The finite element analysis showed that resin composite inlays concentrated more stress in the tooth structure, while ceramic inlays concentrated more stress in the restoration. Non-reparable failures were more frequent in the resin composite inlays groups. CONCLUSIONS: DME was not negative for fatigue and biomechanical behaviors. Resin composite inlays were more resistant to the fatigue test, although the failure mode was more aggressive. CLINICAL SIGNIFICANCE: DME does not impair mechanical behavior. Resin composite inlays failed at higher loads but with a more aggressive failure mode.

Effect of fluoride, chlorhexidine or Nd:YAG on the progression of root dentin demineralization after removal of the demineralized organic matrix

Abstract Quantification of collagen degradation is an important parameter to evaluate dentin caries for preventive aid. Objectives: Evaluate preventive methods against root collagen degradation by the hydroxyproline assay (HYP) and microradiography technique (MRT). Methodology: Five bovine root dentin blocks were obtained and subjected to an artificial demineralization process by acetate buffer (pH 5) to induce carious lesion formation. Samples were subjected to the following therapeutic treatments: 1) 0.12% chlorhexidine for 1 min, 2) 2% fluoride for 1 min, 3) Nd:YAG Laser (400 μm diameter optical fiber, 10 Hz frequency, 60 mJ/pulse energy, 48 J/cm2 energy density, in noncontact mode for 10 s), 4) deionized water (control) for 1 min, 5) MRT control group (without treatment and removal of collagen). Samples were exposed to degradation by a collagenase enzyme for five days. The enzyme solution was collected, by colorimetry in a spectrophotometer, from the collagen matrix for the hydroxyproline release analysis. The same samples were subjected to an additional two days of demineralization to induce the progression of mineral loss. Samples were analyzed by MRT for the visualization of their degraded areas (estimation of lesion depth and mineral loss). ANOVA was applied to compare hydroxyproline release rates. MRT data were subjected to the Kruskal-Wallis test, followed by the Dunn's test. Comparisons between the initial five-day and the subsequent two-day demineralization processes were performed by repeated t-test or Wilcoxon (p<0.05) measurements. Results: The amount of HYP released from the dentin samples failed to show significant differences among the groups (p=0.09). Fluoride and chlorhexidine were able to interact with the samples, reducing the progression of dentin caries after removal of the demineralized organic matrix. CHX was the only treatment able to show significant lower lesion depth than the negative control. Conclusion: Chlorhexidine and fluoride were effective in reducing root caries progression.

Color and surface gloss stability of bis-acryl and resin composite after exposure to cigarette smoke / Estabilidade de cor e brilho superficial de resinas compostas e bisacrílicas após exposição por fumaça de cigarro

Objective: To evaluate color and surface gloss stability of bis-acryl resins and resin composites, submitted to artificial staining with cigarette smoke. Material and Methods: Specimens of each material were prepared (n=15). Two resin composites (GrandioSO [RCG], Filtek Supreme [RCZ]) and five bis-acryl resins (Luxatemp Star [BisLUX], Protemp4 [BisPRO], Structor3 [BisSTR], Visalys Temp [BisVIS] and Yprov [BisYPR]) were tested. Initial color was assessed using a spectrophotometer and surface gloss with a glossmeter. Samples were submitted to smoke exposure (10 cigarettes under 8 minutes per cycle). After 3 and 6 cycles, color and gloss were reassessed. Final readings were performed after brush prophylaxis. Data were analyzed using two-way repeated ANOVA and Tukey's test (p<0.05). Results: Differences and interaction of factors (p<0.01) were detected for both color and gloss readings. Resin composites were the least affected by aging, with gloss reduction after prophylaxis. Differences were detected among bis-acryl resins, with better results for BisLUX and BisPRO. BisPRO and BisSTR, showed reduction in gloss after 60 cigarettes, while BisYPR gloss decreased at all evaluated periods. Conclusion: Resin composites are less susceptible to changes after smoke exposure, while bis-acryl resins results are brand-dependent. Prophylaxis negatively influenced the surface gloss of most of the tested materials (AU)

Objetivo: Avaliar a estabilidade de cor e brilho superficial de resinas compostas e bisacrílicas, submetidos ao manchamento artificial por fumaça de cigarro. Material e Métodos: Foram preparados espécimes de cada material (n=15). Duas resinas compostas (GrandioSO [RCG], Filtek Supreme [RCZ]) e cinco resinas bisacrílicas (Luxatemp Star [BisLUX], Protemp4 [BisPRO], Structor3 [BisSTR], Visalys Temp [BisVIS] e Yprov [BisYPR]) foram testados. A cor inicial foi avaliada usando um espectrofotômetro e o brilho de superfície com um medidor de brilho. As amostras foram submetidas à exposição de fumaça de cigarro (10 cigarros com até 8 minutos por ciclo). Após 3 e 6 ciclos, a cor e o brilho foram reavaliados. As leituras finais foram realizadas após a profilaxia escova de robinson. Os dados foram analisados usando de medidas repetidas e teste de Tukey (p<0,05). Resultados: Foram detectadas diferenças e interação de fatores (p<0,01) tanto para leituras de cor quanto para leituras de brilho. As resinas compostas foram as menos afetados pelo envelhecimento, com redução do brilho após a profilaxia. Foram detectadas diferenças entre as resinas bisacrílicas, com melhores resultados para BisLUX e BisPRO. BisPRO e BisSTR, mostraram redução de brilho após 60 cigarros, enquanto que o brilho da BisYPR diminuiu em todos os períodos avaliados. Conclusão: As resinas compostas são as menos suscetíveis a mudanças após a exposição à fumaça, enquanto os resultados das resinas bisacrílicas são dependentes da marca. A profilaxia influenciou negativamente o brilho de superfície da maioria dos materiais testados.(AU)

Functional or Nonfunctional Cusps Preservation for Molars Restored with Indirect Composite or Glass-Ceramic Onlays: 3D FEA Study.

Evidence regarding the effect of the onlay preparation design for different CAD/CAM restorative materials considering the preservation of cusps is lacking. Molars were 3D-modeled in four preparation designs for onlay restoration: traditional design with functional cusp coverage (TFC), non-retentive design with functional cusp coverage (NFC), traditional design with non-functional cusp coverage (TNFC) and non-retentive design with non-functional cusp coverage (NNFC). The restorations were simulated with two CAD/CAM restorative materials: LD-lithium disilicate (IPS e.max CAD) and RC-resin composite (GrandioBloc). A 100 N axial load was applied to the occlusal surface, simulating the centric contact point. Von Mises (VM) and maximum principal (Pmax) stress were evaluated for restorations, cement layer and dental substrate. The non-retentive preparation design reduced the stress concentration in the tooth structure in comparison to the conventional retentive design. For LD onlays, the stress distribution on the restoration intaglio surface showed that the preparation design, as well as the prepared cusp, influenced the stress magnitude. The non-retentive preparation design provided better load distribution in both restorative materials and more advantageous for molar structure. The resin composite restoration on thenon-functional cusp is recommended when the functional cusp is preserved in order to associate conservative dentistry and low-stress magnitude.