Dental and composite resin discoloration induced by different hydraulic calcium silicate-based cements: two-year in vitro assessment.

Few long-term studies assess the discoloration induced by hydraulic calcium silicate-based cement on dental structures. In addition, as far as we know, no long-term study has assessed the discoloration induced by these cement on composite resin. This in vitro study aimed to assess, during a period of two years, the discoloration potential of different hydraulic calcium silicate-based cements (hCSCs) on the enamel/dentin structure and composite resin restoration. A total of 40 enamel/dentin discs were obtained from bovine incisors, and 40 composite resin discs (10 mm in diameter × 2 mm thick) were fabricated. A 0.8 mm-deep cavity was made in the center of each disc and filled with the following hCSCs (n=10): Original MTA (Angelus); MTA Repair HP (Angelus); NeoMTA Plus (Avalon); and Biodentine (Septodont). An initial color measurement was performed (T0 - baseline). After 7, 15, 30, 45, 90, 300 days, and two years, new color measurements were performed to determine the color (ΔE00), lightness (ΔL'), chroma (ΔC'), hue differences (ΔH'), and whiteness index (WID). For enamel/dentin, the ΔE00 was significant among groups and periods (p<0.05). NeoMTA Plus had the greatest ΔE00. The NeoMTA Plus group had the greatest ΔE00 after two years for composite resin. Significant reduction in lightness was observed for all groups after two years (p<0.05). The most significant WID values were observed after 30 days for Biodentine (enamel/dentin) and MTA Repair HP groups (composite resin) (p<0.05). The hCSCs changed the colorimetric behavior of both substrates, leading to greater darkening over time. The Bi2O3 in the Original MTA seems relevant in the short periods of color change assessment.

The Pulpal Response to Crown Preparation and Cementation.

INTRODUCTION: This study aimed to evaluate the risk factors and occurrence of pulpal disease in patients who received either full-coverage (crowns) or large noncrown restorations (fillings, inlays, or onlays involving ≥3 surfaces). METHODS: A retrospective chart review identified 2177 cases of large restorations placed on vital teeth. Based on the restoration type, patients were stratified into various groups for statistical analysis. After restoration placement, those who required endodontic intervention or extraction were classified as having pulpal disease. RESULTS: Over the course of the study, 8.77% (n = 191) of patients developed pulpal disease. Pulpal disease was slightly more common in the large noncrown group than the full-coverage group (9.05% vs 7.54%, respectively). For patients who received large fillings, there was not a statistically significant difference based on operative material (amalgam vs composite: odds ratio = 1.32 [95% confidence interval, 0.94-1.85], P > .05) or the number of surfaces involved (3 vs 4: odds ratio = 0.78 [95% confidence interval, 0.54-1.12], P > .05). The association between the restoration type and the pulpal disease treatment performed was statistically significant (P < .001). The full-coverage group more frequently underwent endodontic treatment than extraction (5.78% vs 3.37%, respectively). Only 1.76% (n = 7) of teeth in the full-coverage group were extracted compared with 5.68% (n = 101) in the large noncrown group. CONCLUSIONS: It appears that ∼9% of patients who receive large restorations will go on to develop pulpal disease. The risk of pulpal disease tended to be highest in older patients who receive large (4 surface) amalgam restorations. However, teeth with full-coverage restorations were less likely to be extracted.

Efecto de fuentes de polimerización sobre el sellado marginal de restauraciones de resinas de incremento único / Effect of polymerization sources on the marginal sealing of single-increment resin restorations

Introducción: Las resinas de incremento único permiten una fotoactivación de 4 a 5 mm de profundidad, reduciendo el tiempo clínico de aplicación. No obstante, se deben considerar factores como la contracción que puede afectar el sellado marginal de la restauración. Objetivo: Evaluar el efecto de tres fuentes de polimerización sobre el sellado marginal de restauraciones Clase II, realizadas con tres sistemas de resina de incremento único. Métodos: Se realizó un estudio experimental in vitro. El cálculo de la cantidad de unidades de estudio se realizó con el software EPIDAT, para lo cual se tomaron las medias de dos estudios previos. Se realizaron nueve subgrupos según el material de restauración y la fuente de polimerización. En cada diente se confeccionaron dos restauraciones Clase II, que fueron realizadas según las instrucciones del fabricante. Los dientes fueron sometidos a inmersión pasiva en azul de metileno al 1 por ciento por 24 h. Los dientes fueron seccionados mesiodistalmente. Se realizaron fotografías con una cámara Canon y un lente macro 100 mm. La filtración marginal fue medida según una escala del 0 al 4. Los datos fueron analizados con las pruebas de Kruskal-Wallis para la comparación de los grupos. Se estableció un nivel de significancia ajustado al 5 por ciento. Resultados: La resina con menor nivel de filtración fue Filtek Bulkfill, con un 53,3 por ciento correspondiente a la escala 0, mientras que la resina con una mayor filtración fue Tetric N-Ceram Bulk Fill con un 76,7 por ciento (escala 4), similar a Sonicfill (70,0 por ciento). Conclusiones: Las diferentes fuentes de polimerización no influenciaron el nivel de filtración entre los tres sistemas de resinas de incremento único. Filtek Bulkfill presentó un mejor sellado marginal al compararlo con SonicFill y Tetric N-Ceram Bulk Fill(AU)

Introduction: Single-increment resins allow a photoactivation of 4 to 5 mm deep, reducing the clinical time of application. However, factors such as shrinkage that may affect the marginal sealing of the restoration should be considered. Objective: Evaluate the effect of three polymerization sources on the marginal sealing of Class II restorations, carried out with three single-increment resin systems. Methods: An in vitro experimental study was conducted. The calculation of the number of study units was carried out with the EPIDAT software, for which the means of two previous studies were taken. Nine subgroups were made according to the restoration material and the polymerization source. Two Class II restorations were made on each tooth, which were carried out according to the manufacturer's instructions. The teeth were subjected to passive immersion in 1 percent methylene blue for 24h. The teeth were sectioned mesiodistally. Photographs were taken with a Canon camera and a 100mm macro lens. Marginal filtration was measured on a scale of 0 to 4. Data were analyzed with Kruskal-Wallis tests for group comparison. A significance level adjusted to 5 percent was established. Results: The resin with the lowest filtration level was Filtek Bulkfill, with 53.3 percent corresponding to scale 0, while the resin with the highest filtration was Tetric N-Ceram Bulk Fill with 76.7 percent (scale 4), similar to Sonicfill (70.0 percent). Conclusions: The different polymerization sources did not influence the level of filtration between the three single-increment resin systems. Filtek Bulkfill presented a better marginal seal when compared to SonicFill and Tetric N-Ceram Bulk Fill(AU)

Do composite resin polishing systems damage enamel?

Finishing and polishing of composite resin restorations may cause damage to the bordering enamel. Although many studies have investigated the effect of polish on restorative materials, few have quantified the effect on bordering enamel. The objective of this study was to compare enamel loss surrounding composite restorations after finishing and polishing sequences. The null hypothesis was that there would be no difference in enamel loss between different finishing and polishing sequences. Class V preparations on the buccal and lingual surfaces of 15 extracted human molars were restored with a composite resin and assigned to 1 of 2 finishing and polishing sequences, so that each tooth underwent both sequences (n = 15 per sequence). In sequence 1, a tungsten carbide finishing bur and aluminum oxide polishing discs were used; in sequence 2, a diamond finishing bur, aluminum oxide-impregnated finishing cup, and diamond-impregnated polishing cup were used. Tooth surfaces were scanned with an optical scanner after preparation, finishing, initial polishing, and final polishing. The finishing and polishing scans were aligned to the preparation scan using Cumulus software. The depth of enamel surface loss was calculated and statistically analyzed (α = 0.05; paired t test). Most enamel loss (mean [SD]) resulted from the finishing step with the tungsten carbide bur (51.8 [21.3] µm) or diamond bur (43.3 [12.6] µm). Each polishing step increased mean enamel loss by only a few microns. There was no statistically significant difference between the 2 finishing and polishing sequences. The majority of enamel damage during finishing and polishing of composite resin restorations resulted from the finishing burs. Little enamel was removed by either of the tested composite resin polishing systems.

Análise do comportamento da resina composta frente aos diferentes mecanismos de desgaste: uma revisão de literatura / Analysis of the composite resin behavior against different wear mechanisms: a literature review

Introdução:Com o avanço da odontologia e dos materiais dentários, as resinas compostas têm sido amplamente utilizadas nas diversas variedades de restaurações, sejam elas diretas ou indiretas, devido às suas propriedades estéticas. No entanto, existem fatores significati-vos que contribuem para o fracasso das resinas compostas ao longo do tempo, dentre eles, o desgaste.Objetivo:Este trabalho consiste em uma revisão da literatura que objetiva discor-rer acerca dos principais mecanismos de desgaste da resina composta e suas consequências.Metodologia:O presente estudo trata-se de uma revisão da literatura narrativa realizada através de um levantamento bibliográfico de 53 artigos científicos, publicados entre 2010 e 2021. Tendo como fonte as seguintes bases de dados eletrônicos nacionais e internacionais: PubMed, SciELO e Google Acadêmico.Resultados: Perda de brilho, manchamento, infil-tração marginal, cárie recorrente e desgaste (desgaste adesivo, desgaste abrasivo, desgaste por fadiga e desgaste corrosivo) são os principais fatores que contribuem para o fracasso das resinas compostas ao longo do tempo. Conclusão:Os mecanismos de desgaste, sejam de natureza mecânica (física) e/ou química: desgaste adesivo, desgaste por atrito, desgaste abrasivo, desgaste por fadiga e desgaste corrosivo, assim como procedimentos de acaba-mento e polimento e hábitos parafuncionais implicam na perda gradual da resina composta e, consequentemente, geram acúmulo de biofilme, comprometimento gradual da função e estética, redução da dureza e resistência à flexão, que juntos resultam na diminuição da durabilidade clínica das restaurações e geram a necessidade de reparo e/ou substituição da restauração ao longo do tempo.

Introduction: With the advancement of dentistry and dental materials, composite resins have been widely used in different varieties of restorations, whether direct or indirect, due to their aesthetic properties. However, some calculated factors contribute to the failure of composite resins over time, including wear. Objective: This literature review aims to discuss the main wear factors of composite resin and its consequences. Methodology: This is a review of narrative literature carried out through a bibliographic survey of 53 scien-tific articles published between 2010 and 2021. The following national and international electronic databases were used: PubMed, SciELO, and Academic Google. Results: Loss of gloss, staining, marginal infiltration, recurrent caries, and wear (adhesive wear, abrasive wear, fatigue wear, and corrosive wear) are the main factors that contribute to the failure of composite resins over time. Conclusion: The wear mechanisms are of a physical and/or chemical nature: adhesive wear, friction wear, abrasive wear, fatigue wear, and corrosive wear, as well as finishing and polishing procedures, and parafunctional habits imply the gradual loss of the composite resin and, consequently, generate biofilm accumulation, gra-dual impairment of function and esthetics, reduction in hardness, and resistance to flexion, which together result in a decrease in the clinical durability of the restorations, generating the need for restoration and/or replacement over time.Keywords: Composite Resin. Wear. Dental Restoration Wear.

The influence of a selected desensitizer on marginal microleakage of a class V composite restoration subjected to thermocycles: an in vitro study.

INTRODUCTION: Dentin hypersensitivity is a painful clinical condition. The frequency of its occurrence varies from 8 to 57%, depending on tested group and different methods of investigations. Recommended desensitizing agents have different mechanism of action and effectiveness. We are still looking for solutions that will improve their effectiveness and simultaneously allow for wider use of e.g. as a base material, counteracting postoperative hypersensitivity, reducing marginal microleakage. The aim of the study was to assess the effect of a selected desensitizing agent occluding dentin tubules with calcium hydroxyapatite on marginal microleakage formation of a class V composite restorations subjected to thermocycles. MATERIALS AND METHODS: In study it was used 40 molars and premolars, which were alternately assigned into two groups. In both groups standardized cavities were prepared. In the study group (study group - SG) before application of bonding agent Teethmate Desensitizer (f. Kuraray, Noritake Dental Inc., Okayama, Japan) was used. In the control group (control group - CG) OptiBond All-in-one (f. Kerr, Bioggio, Switzerland) bonding agent was used and cavities were filled using composite material Gradia Direct (f. GC Europe N.V., Leuven, Belgium). After storage in saline, teeth were subjected to 600 thermocycles, passive dye penetration test was done, teeth were cut in the area of filling, according to its long axis. Under light microscope magnification value of microleakage was measured and marginal microleakage rate (M) was counted. The results of the tests were statistically analyzed using the package STATISTICA 12.0 (StatSoft, USA). RESULTS: The average value of M for the SG group was 0.46 (min 0.05, max 0.76, SD 0.226) and for CG was 0.22 (min 0, max 0.74, SD 0.235). The differences between M values were statistically significant (p = 0.0094). CONCLUSION: A reduction in the number of retention sites for the bonding system, facilitates the formation of microleakage in the experimental conditions and reduces the degree of adhesion of the composite material to the hard tissues of the tooth.

In vivo Microbial Diversity Analysis on Different Surfaces of Dental Restorative Materials via 16S rDNA Sequencing.

BACKGROUND This study aimed to provide precise material selection guidance for proper clinical restoration and treatment of plaque-related oral diseases, such as dental caries and periodontal diseases. MATERIAL AND METHODS Four groups (n=24) of restorative material sheets (n=24) were prepared using 3M Z350 composite resin (ZR), zinc phosphate cement (ZPC), glass-ionomer (GI), and ICON permeable resin (IPR). Six volunteers wore a plaque-collection device equipped with the 4 restorative material sheets for 48 hours. Plaque samples were collected, and Miseq sequencing was applied to obtain template DNA fragments for microbial diversity analysis. The data were analyzed with nonparametric tests. RESULTS The microbial diversity on the ZPC surface was significantly lower than that on GI and IPR surfaces. The abundance of Firmicutes and Streptococcus on the ZPC surface was significantly higher than on the surfaces of GI and IPR. In contrast, the abundance of Porphyromonas on the surface of ZPC was significantly lower than that on GI and IPR surfaces. (P<0.05). CONCLUSIONS The results of the present study might serve as a basis for material selection under different oral microbial conditions to provide more accurate treatments and restorative procedures in the oral cavity.

Avaliação in vitro da microdureza e porosidade de duas resinas compostas fotopolimerizáveis / Evaluación in vitro de la microdureza y porosidad de dos resinas compuestas fotopolimerizables / In vitro evaluation of the microhardness and porosity of two photopolymerizable composite resins

RESUMO Introdução: Os estudos científicos acerca das propriedades físicas e mecânicas apresentadas pelas resinas compostas são cada vez mais necessários diante da grande variedade de produtos disponíveis no mercado atual, resultante do aumento de sua demanda dentro da odontologia que preza por preparos minimamente invasivos com a devolução das características estéticas e funcionais do elemento dentário. Objetivo: Avaliar e comparar a microdureza e porosidade das resinas compostas fotopolimerizavéis Filtek Z350 XT 3M e Zirconfill Technew. Métodos: Foram confeccionados 10 corpos de prova por amostra (n= 10) submetidos a teste microdureza Vickers e porosidade por microtomografia computadorizada. Resultados: Com relação à presença de porosidades, dada em porcentagem, o grupo da Filtek apresentou os menores valores médios. Quando comparado estatisticamente, os grupos apresentaram diferença estatística (p= 0,019), com uma magnitude de efeito alta. Com relação aos valores de microdureza, o grupo da Filtek apresentou os maiores valores médios. Quando comparados estatisticamente, os grupos não apresentaram diferença estatística (p > 0,05). Conclusões: A porosidade foi significativamente diferente entre os grupos estudados, sendo o grupo Filtek Z350XT de menor percentual. No entanto, os grupos não apresentaram diferença estatística para microdureza, apesar do grupo Filtek Z350XT ter apresentado maior valor médio(AU)

RESUMEN Introducción: Los estudios científicos sobre las propiedades físicas y mecánicas presentadas por las resinas compuestas son cada vez más necesarios ante la gran variedad de productos disponibles en el mercado actual, resultante del aumento de su demanda dentro de la odontología que aprecia por preparaciones mínimamente invasivas con la devolución de las características estéticas y funcionales del elemento dental. Objetivo: Evaluar y comparar la microdureza y porosidad de las resinas compuestas fotopolimerizables Filtek Z350 XT 3M y Zirconfill Technew. Métodos: Se han confeccionado 10 cuerpos de prueba por muestra (n= 10) sometidos a prueba de microdureza Vickers y porosidad por microtomografía computarizada. Resultados: Con respecto a la presencia de porosidades, dada en porcentaje, el grupo de Filtek presentó los menores valores medios. Cuando se comparó estadísticamente, los grupos presentaron una diferencia estadística (p= 0,019), con una magnitud de efecto alto. Con respecto a los valores de microdureza, el grupo de Filtek presentó los mayores valores medios. Cuando se comparó estadísticamente, los grupos no presentaron una diferencia estadística (p> 0,05). Conclusiones: La porosidad fue significativamente diferente entre los grupos estudiados, siendo el grupo Filtek Z350XT de menor porcentaje. Sin embargo, los grupos no presentaron diferencia estadística para microdureza, a pesar de que el grupo Filtek Z350XT presentó un valor medio más alto(AU)

ABSTRACT Introduction: Scientific studies about the physical and mechanical properties of composite resins are increasingly needed in view of the wide variety of products available in the market today, resulting from the increase in their demand for dental care purposes, with a preference for minimally invasive preparations aimed at restoring the esthetic and functional characteristics of the treated element. Objective: Evaluate and compare the microhardness and porosity of the photopolymerizable composite resins Filtek Z350 XT and Zirconfill Technew. Methods: Ten test bodies were developed per sample (n= 10) and subjected to Vickers microhardness and porosity testing by computerized microtomography. Results: With respect to the presence of porosity, expressed in percentages, the Filtek group had the lowest mean values. When compared statistically, the two groups showed a statistical difference (p= 0.019) with a high effect magnitude. Regarding microhardness, the Filtek group had the highest mean values. Statistical comparison did not find any difference between the groups (p> 0.05). Conclusions: Porosity was significantly different in the groups studied, the Filtek Z350XT group exhibiting the lowest percentage. However, the groups did not show any statistical difference concerning microhardness, despite the fact that the Filtek Z350XT group had a higher mean value(AU)

Reasons for direct restoration failure from childhood to adolescence: A birth cohort study.

OBJECTIVES: The aim of this study was to assess the prevalence of direct restorations in posterior teeth in children aged 12, from a birth cohort, and to test the association between the quality of the restorations and individual variables experienced in the life cycle. METHODS: All live-born children in Pelotas, in 2004, were prospectively investigated and a representative sample was assessed for oral conditions at ages 5 and 12. The outcome was the quality of the restoration (satisfactory/unsatisfactory). Independent variables included socioeconomic, behavioral and oral health characteristics at the individual level and the size of cavity and material at the tooth level. Associations were tested using multilevel logistic regression models. RESULTS: A total of 1,000 participants and 249 restorations in the permanent dentition were examined. Most of the restorations were composites (73.5%), while only 6.8% were amalgam. After adjusted analyses, children whose parents received information on how to prevent their child from developing caries before reaching 5 years of age had 91.0% less chance of having an unsatisfactory restoration compared to children whose parents never received information (OR = 0.09; 95% CI 0.01-0.59). Also, the chances of presenting unsatisfactory restorations were 5.3 higher in children at high-risk for untreated dental caries in the permanent dentition, in comparison with children at low risk (OR = 5.32; 95% CI 1.07-26.6). CONCLUSIONS: Low-risk for untreated dental caries and having received information on preventing dental caries, reduced the chance of presenting failed restorations, showing that factors related to individuals play an important role in the quality of restorations. CLINICAL SIGNIFICANCE: Our findings highlight the role that individual-related factors play in restoration longevity in children, reinforcing the need for a patient-centered approach in restorative dentistry.

TEGDMA releasing in resin composites with different filler contents and its correlation with mitochondrial mediated cytotoxicity in human gingival fibroblasts.

Compositions of resin composite exhibit cytotoxicity, especially Triethylene-glycol-dimethacrylate (TEGDMA), yet the underlying mechanisms and its relationship with filler content are poorly understood. Here, specimens of five composites (VITA LC, VITA ZETA, Z350, Filtek P60, and AP-X), containing different filler size and weight, were immersed into culture medium for 72 h. After TEGDMA quantification, the resin composite eluates were used to incubate HGFs. Cellular viability was evaluated. Total reactive oxygen species (ROS) and mitochondrial ROS were detected to assess oxidative stress. Adenosine triphosphate and cytochrome c oxidase (CcO) activity, mitochondrial membrane potential and morphology, mitochondrial biogenesis regulators were analyzed to evaluate mitochondrial functions. Results showed that TEGDMA release negatively correlated to filler size and weight of tested composites. Although cell viability reduction was not significant, total and mitochondrial ROS production showed a positive relationship with the amount of TEGDMA in composite eluates. Furthermore, the expression of mitochondrial biogenesis markers and mitochondrial fusion protein, were markedly elevated in TEGDMA rich eluates, especially in VITA-LC group, shown as elongated mitochondrial morphology and aberrant mitochondrial functions. Overall, TEGDMA could elute easier from those resin composites with less filler content and cause oxidative stress in HGFs via mitochondria dysregulation. These data can be instructive to optimize the synthesis of resin composites from the perspective of biocompatibility. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1132-1142, 2019.

Resin-modified glass ionomer cement vs composite for orthodontic bonding: A multicenter, single-blind, randomized controlled trial.

INTRODUCTION: In this study, we aimed to compare the incidence of new demineralized lesions and bond failures between 2 groups of participants wearing fixed orthodontic appliances bonded with either light-cured resin-modified glass ionomer cement or light-cured composite. METHODS: This trial was a multicenter (6 centers: 2 teaching hospitals, 4 specialist orthodontic practices), single-blinded, randomized controlled trial with 2 parallel groups. Patients aged 11 years or older, in the permanent dentition, and about to start fixed orthodontic treatment in these 6 centers were randomly allocated to have either resin-modified glass ionomer cement or light-cured composite for bonding brackets, forward of the first molars. Pretreatment and day-of-debond digital photographic images were taken of the teeth and assessed by up to 5 clinical and 3 lay assessors for the presence or absence of new demineralized lesions and the esthetic impact. The assessors were masked as to group allocation. RESULTS: We randomized 210 participants, and 197 completed the trial. There were 173 with complete before-and after-digital images of the teeth. The incidence of new demineralized lesions was 24%; but when the esthetic impact was taken into account, this was considerably lower (9%). There was no statistically significant difference between the bracket adhesives in the numbers with at least 1 new demineralized lesion (risk ratio,1.25; 95% confidence interval, 0.74-2.13; P = 0.403) or first-time bracket failure (risk ratio,0.88; 95% confidence interval, 0.67-1.16; P = 0.35). There were no adverse effects. CONCLUSIONS: There is no evidence that the use of resin modified glass ionomer cement over light-cured composite for bonding brackets reduces the incidence of new demineralized lesions or bond failures. There might be other reasons for using resin modified glass ionomer cement. REGISTRATION: This trial was registered at ClinicalTrials.govNCT01925924. PROTOCOL: The protocol is available from the corresponding author on request.

Tooth crown discoloration induced by endodontic sealers: a 3-year ex vivo evaluation.

OBJECTIVES: The aim of this study was to evaluate the tooth crown discoloration induced by commonly used and new-generation endodontic sealers after 1 month and 1 and 3 years. MATERIALS AND METHODS: The crowns of 60 extracted incisors were cut and the pulp chambers were cleaned. The specimens were divided randomly into four groups (n = 15 each). Pulp chambers were filled with Pulpispad in group 1, AH26 in group 2, MTA Fillapex in group 3, and EndoREZ in group 4. Specimen color was measured with a spectrophotometer before and after sealer placement. Commission International de L'Eclairage's (CIE's) lighteness (L*), red-green (a*), yellow-blue (b*) color system values and color difference (ΔE) were recorded at 1 month and 1 and 3 years. Data were analyzed using repeated-measures analysis of variance and Tukey's honestly significant difference test (α = 0.05). RESULTS: All sealers caused discoloration. At 1 month, ΔE values were significantly higher in groups 1 and 2 than in groups 3 and 4 (p < 0.05). At 1 year, ΔE values were significantly lower in group 3 than in the other groups (p < 0.05). At 3 years, ΔE values were significantly higher in group 1 than in the other groups (p < 0.05). CONCLUSIONS: All tested sealers induced varying chromatic alterations. After root canal obturation, thorough debridement of sealers from the pulp chamber is essential for the prevention of sealer-induced discoloration. CLINICAL RELEVANCE: Tooth discoloration induced by endodontic materials is a problem for clinicians and patients and may impair the esthetic of endodontically treated teeth. Therefore, evaluation of long-term discoloration effects commonly used, and new-generation endodontic sealers were purposed in this study.

Development and evaluation of calcium hydroxide-coated, pericardium-based biomembranes for direct pulp capping.

AIM: The aim of the present study was to develop a bovine pericardium biomembrane (BPB) and to evaluate pulp response in vivo. METHODS: A double-layer bovine BPB/chitosan was manufactured, and the porous chitosan side was coated with calcium hydroxide. The microstructure of the matrices was evaluated with electron microscopy. To test pulp response, cavities were prepared on the occlusal surface of Wistar rats' mandibular left first molars and capped with matrices, followed by appropriate adhesives/composite restorations. The animals were divided into three groups: group 1, calcium hydroxide alone; group 2, BPB without calcium hydroxide; and group 3, BPB coated with calcium hydroxide. Specimens were processed and histologically evaluated at 7, 14, and 30 days, postoperatively. RESULTS: Electron microscopy showed porous chitosan surface and a cohesive calcium hydroxide layer. Histological analysis showed that groups 1 and 3 had mild odontoblast layer disorganization, but normal pulp tissue appearance at 7, 14, and 30 days. At the same time points, group 2 showed a loss of general pulp tissue, pulp necrosis, and periapical abscess in some teeth. CONCLUSION: Coated bovine pericardium-based biomembranes resulted in favorable outcomes in cases of pulp exposure after a 30-day observation period, and might protect against injuries caused by adhesive systems and composites.

Effect of Different Liners on Fracture Resistance of Premolars Restored with Conventional and Short Fiber-Reinforced Composite Resins.

PURPOSE: To see whether applying four different liners under short fiber-reinforced composite (SFRC), everX Posterior, compared to conventional composite resin, Z250, affected their strengthening property in premolar MOD cavities. MATERIALS AND METHODS: Mesio-occluso-distal (MOD) cavities were prepared in 120 sound maxillary premolars divided into 10 groups (n = 12) in terms of two composite resin types and 4 liners or no liner. For each composite resin, in 5 groups no liner, resin-modified glass ionomer (RMGI), conventional flowable composite (COFL), self-adhesive flowable composite resin (SAFL), and self-adhesive resin cement (SARC) were applied prior to restoring incrementally. After water storage and thermocycling, static fracture resistance was tested. Data (in Newtons) were analyzed using two-way ANOVA (α = 0.05). RESULTS: Fracture resistance was significantly affected by composite resin type (p = 0.02), but not by the liner (p > 0.05). The interaction of the two factors was not statistically significant (p > 0.05). SFRC exhibited higher fracture strength (1470 ± 200 N) compared to conventional composite resin (1350 ± 290), irrespective of the application of liners. Application of SARC and SAFL liners led to a higher number of restorable fractures for both composite resins. CONCLUSIONS: The four liners can be used without interfering with the higher efficacy of SFRC, compared to conventional composite resins, to improve the fracture strength of premolar MOD cavities.

Effects of New Generation All-Ceramic and Provisional Materials on Fibroblast Cells.

PURPOSE: The purpose of this in vitro study was to evaluate the cytotoxic and apoptotic effects of seven new-generation all-ceramic materials for CAD/CAM (Lava Ultimate [LU], VITA Mark II [VM], InCoris TZI [IC], IPS e.max CAD [EM], VITA Suprinity [VS], Cerasmart [CS], IPS Empress CAD [EC]) and six provisional materials (Protemp 4 [PT], Telio CAD [TC], CAD-Temp [CT], Telio Lab [TL], Temdent Classic [TD], Telio CS C&B [TS]) on L929 mouse fibroblast cells. MATERIALS AND METHODS: 24 disc-shaped specimens (∅ = 5 mm, h = 2 mm) were prepared from each test material. Medium extracts were collected at the 1st, 3rd, and 7th days for each group and tested using the L929 cell line. Cytotoxicity was evaluated using XTT assay, and apoptosis was determined by Annexin-V/PI staining. Data were analyzed using one-way ANOVA, Tukey's multiple comparison tests at a significance level of p < 0.05. RESULTS: The cell viability results among all-ceramic material groups after the 1st and 7th days of incubation periods showed statistically significant differences (p < 0.05). There were significant differences within the ceramic groups in different incubation periods regarding apoptosis rate (p < 0.05). Throughout the entire test period, LU and VM from the CAD/CAM all-ceramic materials and PT and TC from the provisional restoration materials showed cell viability higher than 90%. EC and TD showed the lowest cell viability and highest apoptosis rates in their own groups. For the provisional materials, there were significant differences in cell viability and apoptosis rate in all the incubation periods for each material (p < 0.05). CONCLUSIONS: Although some new-generation CAD/CAM and provisional restoration materials display slight cytotoxicity values, the results are still within the reliable range, and they can safely be used in clinical conditions.

In vivo assessment of genotoxicity in buccal cells of children undergoing tooth restoration.

OBJECTIVES: Whereas dental materials came in direct or close contact with oral tissue, it is a great concern about the biocompatibility of those materials. This study was performed to evaluate possible DNA damage to buccal cells exposed to dental materials. METHODS: This prospective, longitudinal clinical study was conducted over a three months period. Class II restorations were placed in 60 young patients with no previous filling using one of three tested dental materials (two glass ionomers; Ketac Molar and Ionofil Molar and one compomer material; Twinky Star). DNA damage was analysed by micronucleus assays, in buccal exfoliated epithelial cells. RESULTS: In patients treated with Ketac Molar, a significant frequency of micronuclei (p = 0.027) and binucleated cells in samples taken 30 days following restoration (p = 0.029) was confirmed. In patients treated with Twinky Star, a statistically significant increase in the number of binucleated cells in samples taken after 7 and 30 days following restoration (p = 0.001 and p < 0.001, respectively) was observed. In all samples collected 90 days after treatment, there was no statistical difference in the number of any cell changes. CONCLUSION: In this study long-term biocompatibility of tested materials was confirmed. Glass ionomers and compomers are widely used materials in paediatric dentistry, and this study has proved their safety for usage in children.

Evaluation of Radiopacity of Luting Cements Submitted to Different Aging Procedures.

PURPOSE: To evaluate the radiopacity of luting cements submitted to different aging procedures. MATERIALS AND METHODS: Twenty discs (1 × 4 mm) of each of the following cements were prepared: zinc phosphate, RelyX Luting 2, Variolink 2, AllCem, RelyX U200, Multilink, Panavia F2.0, and RelyX ARC. Then, they were randomly divided into two groups (n = 10/group), according to the aging procedure: thermal cycling group and water storage group. Before and after aging procedures, specimens were x-rayed with an aluminum step-wedge (11 steps, 1 mm thick each) and three dental slices (1 mm thick). The radiopacity was evaluated by means of optical density, which was measured using ImageJ software. The values were converted into millimeters of aluminum with a logistic regression calibration curve. The data were analyzed by one-way ANOVA and Tukey post-hoc test (α = 0.05). RESULTS: In the thermal cycling group, RelyX Luting 2, RelyX U200, and Panavia F2.0 showed a statistically significant reduction in radiopacity (p < 0.05). In the water storage group, all cements showed a significant reduction in radiopacity (p < 0.05), and RelyX Luting 2 and Panavia F2.0 performed below the desired ISO 4049 standard. CONCLUSIONS: The radiopacity of luting cements can decrease after aging, especially after 1-year water storage.

[Paradigm shift in conservative dentistry: the end of the amalgam era]. / Paradigmaváltás a fogmegtartó kezelésben: az amalgámkorszak vége.

Dental amalgam has been used for more than 150 years due to its beneficial mechanical properties and durability in dentistry. In the past and to date, many questions about amalgam restorations have arisen, especially regarding the mercury content, which has been the subject of global disputes. By presenting the past and present of the 'amalgam issue', the aim of our paper is to display the current position of international literature. This summary is based on the publications in the PubMed database, the guidelines of the Council of European Dentists. Although the use of dental amalgam is widespread, concerns have been raised about the adverse effect on human health and the environment, focusing on its heavy metal pollution during waste treatment. In 2017, the European Union (EU) adopted the so-called Mercury Regulation, based on the United Nations Minamata Convention on Mercury, the recommendations of which are presented in the present review. This Regulation includes the requirement for EU Member States to develop a national action plan for the phase-down of amalgam. The feasibility plan for complete phase-out may be guaranteed by 2030. The authors discuss the advantages and disadvantages of possible amalgam alternatives by presenting glass-ionomers and resin-based composites. In the future, more material research programmes and long-term follow-up studies are necessary. In addition to several global health organizations, the Council of European Dentists also draws attention to prevent dental caries, expecting to reduce the number of restorations. Orv Hetil. 2018; 159(42): 1700-1709.

Optimizing quality and safety of dental materials.

This paper discusses aspects of quality and safety improvement of the most commonly used dental restorative materials, the resin-based composites. From a patient's perspective, long-lasting resin-based restorations without complications are important. Recurrent caries and fracture are the most common causes for restoration failures. Proper handling and curing of the composites improve the mechanical properties of the restorations and increase safety by reducing exposure to residual methacrylate monomers. A number of compounds have been introduced in restorative materials to reduce the risk of recurrent caries, even though a real breakthrough has not yet been achieved. It is concluded that simple measures may improve the quality and safety of resin-based composite restorations.

Evaluation of marginal leakage after mechanical fatigue cycling of composite inlays luted with different cements.

This in vitro study evaluated the marginal microleakage of composite inlays luted with 3 different cement systems. The null hypothesis was that the luting materials would not influence dye penetration, showing the same degree of microleakage. Thirty-six sound molars were selected, mesio-occlusodistal cavities were prepared, and the teeth were randomly divided into 3 groups (n = 12). Composite resin inlay restorations were made and cemented using a dual-curing resin cement (Calibra), a light-curing flowable composite (Charisma Flow), or a self-adhesive resin cement (RelyX Unicem). The restored teeth were subjected to fatigue cycles and immersed in 0.5% basic fuchsin dye for 24 hours. Two orthogonal cuts were made to enable evaluation of dye penetration at the cervical and occlusal margins. The sections were evaluated with a 4-point scale ranging from 0 (no penetration) to 3 (penetration up to the cavity floor [occlusal margins] or axial wall [cervical margins]). The Calibra and Charisma Flow groups showed greater microleakage, notably at the cervical margins, whereas RelyX Unicem specimens showed the least dye penetration. Significant differences were found between the Calibra and Charisma Flow groups and between the Charisma Flow and RelyX Unicem groups (P < 0.05). No statistically significant differences were detected between the Calibra and RelyX Unicem groups. The microleakage associated with the flowable composite was significantly greater than that associated with both resin cements, results that discourage its use for luting of Class II composite inlays.