Comparative evaluation of probiotic solutions on surface roughness and microhardness of different restorative materials and enamel.

This research study aimed to investigate the impact of probiotic mouthwash and kefir on the surface characteristics, specifically surface roughness and microhardness, of different restorative materials, as well as permanent and deciduous tooth enamels. Thirty disc-shaped specimens were prepared from composite resin (G-ænial Posterior (GP)), polyacid-modified composite resin (compomer) (Dyract-XP (DXP)), and resin-modified glass ionomer cement (Ionoseal (IS)). Additionally, thirty specimens of enamel were obtained from permanent teeth (PT) and thirty from deciduous teeth (DT) by embedding buccal and lingual sections, acquired through vertical sectioning of 15 permanent and 15 deciduous human tooth crowns in the mesiodistal orientation within acrylic resin blocks. The specimens were then categorized into three distinct groups and immersed for 14 days in one of the following solutions: distilled water, kefir or probiotic mouthwash. The mean surface roughness values of all specimens were assessed using an atomic force microscope, while the mean surface microhardness was measured using a Vickers hardness measuring instrument. The results revealed a statistically significant difference in mean surface roughness among the various restorative materials (p < 0.001). Among the restorative materials, the IS material exhibited notably higher mean surface roughness values than other restorative materials and tooth enamel, while no significant differences were observed between the PT and DT groups. Importantly, the main effect of the solutions under investigation was not statistically significant (p = 0.208). No significant difference was found between the surface roughness values of specimens subjected to the different solutions. When evaluating the effects of materials and solutions on microhardness, the main effects of material and solution variables and the influence of material-solution interactions were statistically significant (p < 0.001). Taken together, these results indicate that consistent use of kefir or probiotic mouthwashes may impact the surface properties of various restorative materials and tooth enamel.

Cost-effectiveness of restorative treatments for permanent molars with severe molar incisor hypomineralization: perspectives for the Brazilian public health system.

OBJECTIVES: To undertake a cost-effectiveness analysis of restorative treatments for a first permanent molar with severe molar incisor hypomineralization from the perspective of the Brazilian public system. MATERIALS AND METHODS: Two models were constructed: a one-year decision tree and a ten-year Markov model, each based on a hypothetical cohort of one thousand individuals through Monte Carlo simulation. Eight restorative strategies were evaluated: high viscosity glass ionomer cement (HVGIC); encapsulated GIC; etch and rinse adhesive + composite; self-etch adhesive + composite; preformed stainless steel crown; HVGIC + etch and rinse adhesive + composite; HVGIC + self-etch adhesive + composite, and encapsulated GIC + etch and rinse adhesive + composite. Effectiveness data were sourced from the literature. Micro-costing was applied using 2022 USD market averages with a 5% variation. Incremental cost-effectiveness ratio (ICER), net monetary benefit (%NMB), and the budgetary impact were obtained. RESULTS: Cost-effective treatments included HVGIC (%NMB = 0%/ 0%), encapsulated GIC (%NMB = 19.4%/ 19.7%), and encapsulated GIC + etch and rinse adhesive + composite (%NMB = 23.4%/ 24.5%) at 1 year and 10 years, respectively. The benefit gain of encapsulated GIC + etch and rinse adhesive + composite in relation to encapsulated GIC was small when compared to the cost increase at 1 year (gain of 3.28% and increase of USD 24.26) and 10 years (gain of 4% and increase of USD 15.54). CONCLUSION: Within the horizon and perspective analyzed, the most cost-effective treatment was encapsulated GIC restoration. CLINICAL RELEVANCE: This study can provide information for decision-making.

Effects of 3D-Printing Technology and Cement Type on the Fracture Resistance of Permanent Resin Crowns for Primary Teeth.

PURPOSE: To evaluate the fracture resistance of permanent resin crowns for primary teeth produced using two different 3D-printing technologies (digital light processing [DLP] and stereolithography [SLA]) and cemented with various luting cements (glass ionomer, resin-modified glass ionomer, and self-adhesive resin cement), whether thermally aged or not. MATERIALS AND METHODS: A typodont primary mandibular second molar tooth was prepared and scanned, and a restoration design was created with web-based artificial intelligence (AI) dental software. A total of 96 crowns were prepared, and 12 experimental groups were generated according to the cement type, 3Dprinting technology (DLP or SLA), and thermal aging. Fracture resistance values and failure types of the specimens were noted. The results were statistically analyzed with three-way ANOVA and Tukey HSD tests (α = .05). RESULTS: The results of the three-way ANOVA showed that there was an interaction among the factors (3D-printing technology, cement type, and thermal aging) (P = .003). Thermal aging significantly decreased the fracture resistance values in all experimental groups. DLP-printed crowns showed higher fracture resistance values than SLA-printed crowns. Cement type also affected the fracture resistance, with glass ionomer cement showing the lowest values after aging. Resin-modified glass ionomer and resin cements were more preferable for 3D-printed crowns. CONCLUSIONS: The type of cement and the 3D-printing technology significantly influenced the fracture resistance of 3D-printed permanent resin crowns for primary teeth, and it was decided that these crowns would be able to withstand masticatory forces in children.

Bonding of Composite Cements Containing 10-MDP to Zirconia Ceramics Without Dedicated Ceramic Primer.

PURPOSE: To measure zirconia-to-zirconia microtensile bond strength (µTBS) using composite cements with and without primer. MATERIALS AND METHODS: Two Initial Zirconia UHT (GC) sticks (1.8x1.8x5.0 mm) were bonded using four cements with and without their respective manufacturer's primer/adhesive (G-CEM ONE [GOne] and G-Multi Primer, GC; Panavia V5 [Pv5]), and Panavia SA Cement Universal [PSAu], and Clearfil Ceramic Plus, Kuraray Noritake; RelyX Universal (RXu) and Scotchbond Universal Plus [SBUp], 3M Oral Care). Specimens were trimmed to an hour-glass shaped specimen whose isthmus is circular in cross-section. After 1-week water storage, the specimens were either tested immediately (1-week µTBS) or first subjected to 50,000 thermocycles (50kTC-aged µTBS). The fracture mode was categorized as either adhesive interfacial failure, cohesive failure in composite cement, or mixed failure, followed by SEM fracture analysis of selected specimens. Data were analyzed using linear mixed-effects statistics (α = 0.05; variables: composite cement, primer/adhesive application, aging). RESULTS: The statistical analysis revealed no significant differences with aging (p = 0.3662). No significant difference in µTBS with/without primer and aging was recorded for GOne and PSAu. A significantly higher µTBS was recorded for Pv5 and RXu when applied with their respective primer/adhesive. Comparing the four composite cements when they were applied in the manner that resulted in their best performance, a significant difference in 50kTC-aged µTBS was found for PSAu compared to Pv5 and RXu. A significant decrease in µTBS upon 50kTC aging was only recorded for RXu in combination with SBUp. CONCLUSION: Adequate bonding to zirconia requires the functional monomer 10-MDP either contained in the composite cement, in which case a separate 10-MDP primer is no longer needed, or in the separately applied primer/adhesive.

Microhardness and elemental analysis of ion-releasing restoration/ dentin interface following enzymatic chemomechanical caries excavation.

BACKGROUND: This study was conducted to compare chemical, elemental and surface properties of sound and carious dentin after application of two restorative materials resin-modified glassionomer claimed to be bioactive and glass hybrid restorative material after enzymatic chemomechanical caries removal (CMCR) agent. METHODS: Forty carious and twenty non-carious human permanent molars were used. Molars were randomly distributed into three main groups: Group 1 (negative control) - sound molars, Group 2 (positive control) - molars were left without caries removal and Group 3 (Test Group) caries excavated with enzymatic based CMCR agent. After caries excavation and restoration application, all specimens were prepared Vickers microhardness test (VHN), for elemental analysis using Energy Dispersive Xray (EDX) mapping and finally chemical analysis using Micro-Raman microscopy. RESULTS: Vickers microhardness values of dentin with the claimed bioactive GIC specimens was statistically higher than with glass hybrid GIC specimens. EDX analysis at the junction estimated: Calcium and Phosphorus of the glass hybrid GIC showed insignificantly higher mean valued than that of the bioactive GIC. Silica and Aluminum mean values at the junction were significantly higher with bioactive GIC specimens than glass hybrid GIC specimen. Micro-raman spectroscopy revealed that bioactive GIC specimens showed higher frequencies of v 1 PO 4, which indicated high level of remineralization. CONCLUSIONS: It was concluded that ion-releasing bioactive resin-based restorative material had increased the microhardness and remineralization rate of carries affected and sound dentin. In addition, enzymatic caries excavation with papain-based CMCR agent has no adverse effect on dentin substrate.

Effect of Bonding Agents on the Shear Bond Strength of Tooth-colored Restorative Materials to Dentin: An In Vitro Study.

AIM: The aim of the study is to determine the difference in the shear bond strengths to dentin among dental composite (Filtek Z350®, 3M), compomer (Dyract Flow®, Dentsply) and Giomer (Beautifil®, Shofu) with 3MTM Single BondTM Universal Adhesive (SBU) (7th generation, self-etch, single solution adhesive) and AdperTM Single Bond 2 Adhesive (ASB) (5th generation, total-etch, two solution adhesive). MATERIALS AND METHODS: Sixty extracted human permanent teeth were collected, cleansed of debris, and placed in distilled water. The samples were segregated into two groups depicting the two bonding agents-AdperTM (ASB) and 3MTM Single Bond Universal (SBU) and sub-grouped into three groups depicting the three restorative materials (Composite, Giomer, and Compomer) used. Groups were respresented as follows: Group I-ASB + Composite; Group II-ASB + Giomer; Group III-ASB + Compomer; Group IV-SBU + Giomer; Group V-SBU + Compomer; Group VI-SBU + Composite. After applying the bonding agent as per the manufacturer's instructions, following which the restorative material was placed. A Universal Testing Machine (Instron 3366, UK) was employed to estimate the shear bond strength of the individual restorative material and shear bond strengths were calculated. RESULTS: Composite bonded with SBU (group VI) displayed the greatest shear strength (11.16 ± 4.22 MPa). Moreover, Giomers and flowable compomers displayed better bond strengths with ASB compared with their SBU-bonded counterparts. CONCLUSION: These results mark the importance of careful material selection in clinical practice and the bonding agent used to achieve optimal bond strength and enhance the clinical longevity and durability of dental restorations. CLINICAL SIGNIFICANCE: From a clinical perspective, to avoid a compressive or a shear failure, it would be preferrable to use a direct composite restorative material with SBU (Single bond universal adhesive, 7th generation) to achieve maximum bond strength. How to cite this article: Kuchibhotla N, Sathyamoorthy H, Balakrishnan S, et al. Effect of Bonding Agents on the Shear Bond Strength of Tooth-colored Restorative Materials to Dentin: An In Vitro Study. J Contemp Dent Pract 2024;25(3):245-249.

[Total rehabilitation in case of amelogenesis imperfecta].

The aim of the treatment of this case was to restore the form, function and aesthetics of all teeth in a patient with amelogenesis imperfecta within the age limit of the disability insurance (IV). Single-tooth zirconia crowns were selected as the treatment of choice and cemented with a conventional glass ionomer cement. For the maintenance of the oral rehabilitation and the protection of the reconstructions a michigan splint was produced and instructed to be carried over night.

Management of severity lesions of hypomineralized molars (MIH) with different treatment alternatives: 9-month results of a clinical trial.

The aim of this study was to evaluate the 9-month clinical performance of different materials and treatment procedures in teeth with MIH in children, and to evaluate the effectiveness of Papacarie gel as a deproteinization agent. The study included 90 children (aged 8-15) who had 189 first permanent molars with MIH were restored randomly with 4 different materials/methods. Equia Forte HT (GC, Tokyo, Japan) was used in Group 1; In Group 2, G-eanial composite (GC, Tokyo, Japan) was used with a Fuji IX (GC, Tokyo, Japan) base; In Group 3 and Group 4, EverX Posterior (GC, Tokyo, Japan) base and G-eanial composite (GC, Tokyo, Japan) were used. In group 4, deproteinization was performed with Papacarie Duo gel (F&A, Sao Paulo, Brazil). The restorations were evaluated at 3-month intervals for 9 months using modified United States Public Health Service (USPHS) criteria. The overall recall rate was 94.1% for every 3-month clinical evaluation over 9 months. A total of 9 restorations were unsuccessful. Surface roughness of Group 1 was statistically different from all other groups in all control periods (p < 0.05). Marginal adaptation of Group 2 was found to be significantly different from Groups 3 and 4 at the both of 6th and 9th month controls. There was no significant difference between the groups in terms of retention, color match, marginal discoloration and secondary caries in all control months. Restoration of MIH with Equia Forte HT is almost as successful as composites. The use of dentin replacement materials instead of glass ionomer cements as a base in composite restorations shows better results. Papacarie deproteinization showed similar success with other composite groups. This study was the first clinical study in which Papacarie was used for deproteinization in teeth with MIH and will thus contribute to the literature.

Evaluation of Retentive Strength of 50 Endodontically-Treated Single-Rooted Mandibular Second Premolars Restored with Cast Post Cores Using 5 Common Luting (Cement) Agents.

BACKGROUND A luting agent is a dental cement used to secure a dental restoration. This study aimed to evaluate retentive strength of 50 endodontically-treated single-rooted mandibular second premolars (extracted) restored using 5 common luting (cement) agents. MATERIAL AND METHODS Fifty single-rooted mandibular second premolars with adequate root length and uniform size/shape were decoronated. After completing endodontic biomechanical preparation and obturation, root canals of all specimens were prepared to receive a cast post core. Depending upon cementation type, CPC specimens were divided in 5 groups (10 each) (Gp): Zinc phosphate (Gp ZP), polycarboxylate (Gp PC), glass ionomer (Gp GI), resin-modified glass ionomer (Gp RGI), and resin cement (Gp RC). Retentive strength was determined using the adhesive failure pull-out test. Mean/standard deviations were calculated for tensile forces (in kilograms) and differences were determined using analysis of variance (ANOVA). Multiple comparison was performed using the t test. A P value of ≤0.05 indicated a statistically significant difference. RESULTS The order of mean tensile strength from higher to lower was Gp RC (21.46) >Gp RGI (18.17) >Gp GI (16.07) >Gp ZP (15.33) >Gp PC (13.63). Differences in retentive strengths between the cements were significant (P≤0.05). Multiple-group comparisons showed that except for Gp ZP and Gp GI, all groups differed significantly from each other. CONCLUSIONS All investigated cements provided optimal retentive strengths, with wide differences between them. Resin cements should be used when CPC removal is not anticipated, while polycarboxylate or zinc phosphate should be used if CPC removal is anticipated.

Compressive strength and fluoride release profile of a glass ionomer cement reinforced with silver-hydroxyapatite-silica hybrid nanoparticles: An in vitro study.

OBJECTIVES: This study aimed to prepare a glass ionomer (GI) cement reinforced with silver-hydroxyapatite-silica (Ag/HA/Si) hybrid nanoparticles and assess its compressive strength and fluoride release profile. MATERIAL AND METHODS: In this in vitro, experimental study, 60 cylindrical specimens were fabricated with 4mm diameter and 6mm height in 6 groups (n=10) using BracePaste composite, GC Fuji II LC pure RMGI, and RMGI reinforced with 0.1wt%, 0.5wt%, 1wt%, and 2wt% Ag/HA/Si hybrid nanoparticles. The specimens were subjected to compressive force in a universal testing machine to measure their compressive strength (MPa). To assess their fluoride release profile, discs with 3mm diameter and 2mm thickness were fabricated from Fuji II LC pure resin-modified glass ionomer (RMGI), and RMGI with 0.1wt%, 0.5wt%, 1wt%, and 2wt% hybrid nanoparticles, and the concentration of released fluoride was measured by a digital ion-selective electrode. Data were analysed by ANOVA and Scheffe test (alpha=0.05). RESULTS: The compressive strength was 114.14MPa for BracePaste composite, and 97.14, 97.84, 100.65, 109.5, and 89.33MPa for GI groups with 0%, 0.1%, 0.5%, 1% and 2% hybrid nanoparticles, respectively, with no significant difference among them (P=0.665). Addition of 1% (0.21±0.07µg/mL, P=0.029) and 2% (0.45±0.22µg/mL, P=0.000) hybrid nanoparticles to RMGI significantly increased the amount of released fluoride, compared with the control group (0.09±0.03µg/mL). CONCLUSIONS: Addition of Ag/HA/Si hybrid nanoparticles to RMGI in the tested concentrations had no significant effect on its compressive strength but addition of 1wt% and 2wt% concentrations of Ag/HA/Si hybrid nanoparticles increased its fluoride release potential.

A scoping review of the influence of clinical contaminants on bond strength in direct adhesive restorative procedures.

OBJECTIVE: Clinical contamination during direct adhesive restorative procedures can affect various adhesive interfaces differently and contribute to bulk failure of the restorations. This review aims to summarise the current knowledge on the influence of a variety of clinical contaminants on the bond strength at various adhesive interfaces during adhesive restorative procedures and identify gaps in the literature for future research. DATA AND SOURCES: An electronic database search was performed in PubMed and EMBASE to identify articles that investigated the influence of contaminants on direct restorative bonding procedures. A data-charting form was developed by two researchers to capture the key characteristics of each eligible study. STUDY SELECTION: The initial search yielded 1,428 articles. Fifty-seven articles published between 1 Jan 2007 and 25 Oct 2023 were included in the final review. Thirty-three of the articles examined the influence of saliva contamination, twelve articles examined the influence of blood contamination, and twenty-five articles examined the influence of other contaminants. CONCLUSION: Saliva contamination exerted less influence on the decrease in bond strength when self-etch systems were used, compared to when etch-and-rinse systems were used. Blood contamination adversely affected the bond strength at the interface between resin composite and dentine, and resin composite and resin-modified glass ionomer cement. Treating contaminated surfaces with water spray for 10-30 s followed by air drying could be effective in recovering bond strength following saliva and blood contamination. CLINICAL SIGNIFICANCE: This scoping review provides a valuable overview of the range of potential clinical contaminants that can influence the bond strength between different interfaces in direct adhesive restorative procedures. Additionally, it identifies potential decontamination protocols that can be followed to restore and enhance bond strength.

Cell viability assessment and ion release profiles of GICs modified with TiO2- and Mg-doped hydroxyapatite nanoparticles.

OBJECTIVES: To assess and compare the cell viability and ion release profiles of two conventional glass ionomer cements (GICs), Fuji IX and Ketac Molar EasyMix, modified with TiO2 and Mg-doped-HAp nanoparticles (NPs). METHODS: TiO2 NPs, synthesized via a sol-gel method, and Mg-doped hydroxyapatite, synthesized via a hydrothermal process, were incorporated into GICs at a concentration of 5 wt.%. The biocompatibility of prepared materials was assessed by evaluating their effects on the viability of dental pulp stem cells (DPSCs), together with monitoring ion release profiles. Statistical analysis was performed using One-way analysis of variance, with significance level p < 0.05. RESULTS: The addition of NPs did not significantly affect the biocompatibility of GICs, as evidenced by comparable decreased levels in cell viability to their original formulations. Distinct variations in cell viability were observed among Fuji IX and Ketac Molar, including their respective modifications. FUJI IX and its modification with TiO2 exhibited moderate decrease in cell viability, while other groups exhibited severe negative effects. While slight differences in ion release profiles were observed among the groups, significant variations compared to original cements were not achieved. Fluoride release exhibited an initial "burst release" within the initial 24 h in all samples, stabilizing over subsequent days. CONCLUSIONS: The addition of NPs did not compromise biocompatibility, nor anticariogenic potential of tested GICs. However, observed differences among FUJI IX and Ketac Molar, including their respective modifications, as well as induced low viability of DPSC by all tested groups, suggest the need for careful consideration of cement composition in their biological assessments. CLINICAL SIGNIFICANCE: The findings contribute to understanding the complex interaction between NPs and GIC matrices. However, the results should be interpreted recognizing the inherent limitations associated with in vitro studies. Further research avenues could explore long-term effects, in vivo performance, and potential clinical applications.

Effect of pH on the solubility and volumetric change of ready-to-use Bio-C Repair bioceramic material.

Acidic pH can modify the properties of repair cements. In this study, volumetric change and solubility of the ready-to-use bioceramic repair cement Bio-C Repair (BCR, Angelus, Londrina, PR, Brazil) were evaluated after immersion in phosphate-buffered saline (PBS) (pH 7.0) or butyric acid (pH 4.5). Solubility was determined by the difference in initial and final mass using polyethylene tubes measuring 4 mm high and 6.70 mm in internal diameter that were filled with BCR and immersed in 7.5 mL of PBS or butyric acid for 7 days. The volumetric change was established by using bovine dentin tubes measuring 4 mm long with an internal diameter of 1.5 mm. The dentin tubes were filled with BCR at 37°C for 24 hours. Scanning was performed with micro-computed tomography (micro-CT; SkyScan 1176, Bruker, Kontich, Belgium) with a voxel size of 8.74 µm. Then, the specimens were immersed in 1.5 mL of PBS or butyric acid at and 37 °C for 7 days. After this period, a new micro-CT scan was performed. Bio-C Repair showed greater mass loss after immersion in butyric acid when compared with immersion in PBS (p<0.05). Bio-C Repair showed volumetric loss after immersion in butyric acid and increase in volume after immersion in PBS (p<0.05). The acidic pH influenced the solubility and dimensional stability of the Bio-C Repair bioceramic cement, promoting a higher percentage of solubility and decrease in volumetric values.

Cytotoxic effect of dental luting cement on human gingival mesenchymal stem cell and evaluation of cytokines and growth factor release - An in vitro study.

AIM: In routine dental care, various dental luting cements are utilized to cement the dental prosthesis. Thus, the aim of the current study was to assess the Cytotoxic effect of three different dental luting cements on human gingival mesenchymal stem cell and evaluation of cytokines and growth factors release. SETTINGS AND DESIGN: Cytotoxicity of glass ionomer cement (GIC), resin modified glass ionomer cement (RMGIC) and resin cement (RC) on the human gingival mesenchymal stem cells (HGMSCs) was evaluated. Amongst the cements tested, least cytotoxic cement was further tested for the release of cytokines and growth factors. MATERIALS AND METHODS: MTT test was used to evaluate the cytotoxicity of the dental luting cements at 1 h, 24 h, and 48 h on HGMSCs. Cytokines such as interleukin (IL) 1α & IL 8 and growth factors such as platelet derived growth factor & transforming growth factor beta release from the least cytotoxic RC was evaluated using flow cytometry analysis. STATISTICAL ANALYSIS USED: The mean absorbance values by MTT assay and cell viability at various time intervals between four groups were compared using a one way analysis of variance test and Tukey's post hoc test. The least cytotoxic RC group and the control group's mean levels of cytokines and growth factors were compared using the Mann-Whitney test. RESULT: As exposure time increased, the dental luting cement examined in this study were cytotoxic. RC was the least cytotoxic, RMGIC was moderate and glass ionomer cement showed the highest cytotoxic effect. Concomitantly, a significant positive biological response of gingival mesenchymal stem cells with the release of ILs when exposed to the RC was observed. CONCLUSION: For a fixed dental prosthesis to be clinically successful over the long term, it is imperative that the biocompatibility of the luting cement be taken into account in order to maintain a healthy periodontium surrounding the restoration.

Effect of various surface coating methods on surface roughness, micromorphological analysis and fluoride release from contemporary glass ionomer restorations.

OBJECTIVE: To evaluate the effect of various surface coating methods on surface roughness, micromorphological analysis and fluoride release from contemporary resin-modified and conventional glass ionomer restorations. MATERIALS & METHODS: A total of 72 permanent human molars were used in this study. The teeth were randomly assigned into 2 groups according to type of restorative materials used; resin modified glass ionomer cement and conventional glass ionomer (SDI Limited. Bayswater Victoria, Australia). Each group was subdivided into 3 subgroups according to the application of coat material; Sub-group1: without application of coat; Sub-group2: manufacturer recommended coat was applied and sub-group3: customized (vaseline) coat was applied. Each group was then subdivided into two divisions according to the time of testing; immediate (after 24 h) and delayed (after 6 months of storage). Three specimens from each sub-group were selected for surface roughness test (AFM) and another 3 specimens for the micromorphological analysis using scanning electron microscope (SEM). For the fluoride release test, a total of 60 cylindrical discs were used (n = 60). The discs were randomly split into 2 groups according to type of restorative materials used (n = 30); resin modified glass ionomer cement and conventional glass ionomer. Each group was subdivided into 3 subgroups (n = 10) according to the application of the coat material; Sub-group1: without application of coat; Sub-group2: with the manufacturer recommended coat and sub-group3: with application of customized (vaseline) coat. Data for each test was then collected, tabulated, were collected, tabulated, and tested for the normality with Shapiro-Wilk test. Based on the outcome of normality test, the significant effects of variables were assessed using appropriate statistical analysis testing methods. RESULTS: Regarding the data obtained from surface roughness test, Shapiro-Wilk test showed normal distribution pattern of all values (p > 0.05). Accordingly, Two-way ANOVA outcome showed that the 'type of restoration' or 'test time' had statistically significant effect on the AFM test (p < 0.05). Regarding Fluoride specific ion electrode test 2-way ANOVA followed by Least Significant Difference (LSD) Post-hoc test revealed significant difference among the groups (p < 0.05). It showed that SDI GIC group after 14 days of measurement had the highest mean of fluoride release (36.38 ± 3.16 PPM) and SDI RMGIC after 30 days of measurement had the second highest mean of fluoride release (43.28 ± 1.89 PPM). Finally, regarding the micromorphological analysis using SEM, a slight difference was observed between the studied groups. CONCLUSIONS: Based on the results of this study, various coatings enhance surface roughness in the initial 24 h of restoration insertion. Different coat types seems that have no influence on fluoride release and the micromorphological features of the restoration/dentin interface.

Influence of pozzolanic addition on strength and microstructure of metakaolin-based concrete.

The intent of this study is to explore the physical properties and long-term performance of concrete made with metakaolin (MK) as a binder, using microsilica (MS) and nanosilica (NS) as substitutes for a portion of the ordinary Portland cement (OPC) content. The dosage of MS was varied from 5% to 15% for OPC-MK-MS blends, and the dosage of NS was varied from 0.5% to 1.5% for OPC-MK-NS blends. Incorporation of these pozzolans accelerated the hardening process and reduced the flowability, consistency, and setting time of the cement paste. In addition, it produced a denser matrix, improving the strength of the concrete matrix, as confirmed by scanning electron microscopy and X-ray diffraction analysis. The use of MS enhanced the strength by 10.37%, and the utilization of NS increased the strength by 11.48% at 28 days. It also reduced the penetrability of the matrix with a maximum reduction in the water absorption (35.82%) and improved the resistance to the sulfate attack for specimens containing 1% NS in the presence of 10% MK. Based on these results, NS in the presence of MK can be used to obtain cementitious structures with the enhanced strength and durability.

Influence of rice husk ash on the mechanical properties of ultra-high strength engineered cementitious composites (UHS-ECC).

Generally, UHS-ECC should consume massive cement, which is negative to its sustainability as cement production leads to 8% of global CO2 emissions. To decrease the cost of production and carbon emissions of UHS-ECC, rice husk ash was employed to replace the cement as a supplementary cementitious material in this study. Experiment results illustrate that blending rice husk ash (RHA) would decrease the fluidity of mortar. Furthermore, the green UHS-ECC shows a maximum compressive strength of 130.3 MPa at 28 days when RHA content was 20% of cement. The ultimate tensile strength of UHS-ECCs first increased and then decreased, while both tensile strain and strain energy presented an opposite tendency. At the micro-scale, if RHA content was lower than 20% of cement, incorporating RHA can significantly decreasing fiber bridging complementary energy of UHS-ECC, thus reducing pseudo strain hardening energy (PSHenergy) index, which finely agrees with the degradation of ductility of UHS-ECCs. To guarantee the features of ultra-high strength, acceptable workability, and high tensile ductility, the RHA dosage should not be in excess 20% of cement. These researched results are prospected to the contribution of pozzolanic RHA on the efficient usage of sustainable UHS-ECC.

A quantitative and qualitative investigation into the management of carious primary molars by foundation dentists in primary care in the South East of England.

Introduction Dental caries is the most common reason for hospital admission of children aged 5-9 in the UK. Better management of caries in primary molars would reduce the number of children requiring treatment in hospitals; however, little research has been done into why primary care clinicians do not use an evidence-based approach to caries management for deciduous molars.Aims The aim of this paper is to identify the rationale behind caries management techniques used in primary care, as well as the choice of materials and long-term success of restorations placed.Materials and methods Use of a retrospective audit and a focus group with primary care clinicians to provide an insight into the management of carious primary molars and the barriers to achieving gold standard care.Results Glass ionomer cements (GICs) were the restoration of choice in primary care. Lack of time, equipment availability and clinician inexperience were cited as to why Hall crowns were not commonly placed.Conclusions The barriers to gold standard management of carious primary molars in practice are wide-ranging but tend to focus on the limitations of NHS care under the units of dental activity system. Lack of time and cost of materials encouraged clinicians to adopt a 'quick fix' approach in GIC.

Performance evaluation of carbon quantum dots impregnated glass ionomer cement to avoid peri-implant disease.

Dental cement residues exacerbate peri-implant tissue irritation and peri-implantitis. The present study aims to evaluate the cytotoxicity, physiochemical, optical, and rheological properties of carbon quantum dots (CQDs) impregnated glass ionomer cement (GIC). Surface passivated fluorescent CQDs were synthesized using citric acid via thermal decomposition and blended with GIC. Characterization studies and rheological measurements were made to evaluate their performance. 3D-printed dental implant models cemented with GIC and GIC-CQD were compared to analyze excess cement residues. MTT assay was performed with human dental pulp stem cells (hDPSCs) and statistically analyzed using ANOVA and Tukey's test. CQDs with a particle dimension of ∼2 nm were synthesized. The amorphous property of GIC-CQD was confirmed through XRD. The fluorescence properties of GIC-CQD showed three times higher emission intensity than conventional GIC. GIC-CQD attained maturation with a setting time extended by 64 s than GIC. Cement residue of size 2 mm was detected with a UV light excitation at a distance between 5 to 10 cm. Biocompatibility at 0.125 mg ml-1dilution concentrations of GIC-CQD showed viability greater than 80% to hDPSCs. For the first time, we report that CQDs-impregnated GIC is a unique and cost-effective strategy for in-situ detection of excess cement rapidly using a hand-held device. A novel in-situ rapid detection method enables the dentist to identify residual cement of size less than 2 mm during the implantation. Therefore, GIC-CQD would replace conventional GIC and help in the prevention of peri-implant diseases.

Comparative study of physical-chemical properties of bioactive glass ionomer cement.

This study analyzed the physical-chemical properties of bioactive ionomer materials. Cention N bioactive materials were evaluated chemically activated (CN) and light-cured (CN-LC), Equia Forte Fill (EQUI); conventional resin composite Filtek Z350 XT (Z350); resin glass ionomer cement Riva light Cure (RIVA) and flowable resin composite Filtek Bulk Fill Flow (BULK-F) were evaluated. Sixty specimens (n=10) were prepared for sorption (SR), solubility (SL), flexural strength (FS), shrinkage stress (SS), conversion degree (CD), microhardness (MI), and surface roughness (SR) tests. Non-cured and light-cured materials were assessed on FTIR. 30 human molar teeth were used in the bond strength test (BS). Data were subjected to ANOVA and post-hoc Tukey's test (5% of significance). EQUI showed more sorption in SR and no statistical difference from RIVA and CN-LC. CN group showed more solubility and EQUI presented less (p<0.05). BULK-F showed higher FS (MPa), without differences from CN and Z350, whereas EQUI presented the lowest FS not differing from RIVA. BULK-F and CN-LC showed more shrinkage stress differing from EQUI. CN-LC and CN showed higher CD differing from the other which showed no differences (p>0.05) between them. EQUI showed the highest hardness (p<0.05) in MI. There were no differences (p>0.05) in SR (µm). Z350 and BULK-F presented higher BS, whereas CN-LC showed the lowest, although not differing from EQUI and RIVA. Equia Forte's solubility and microhardness make it a good alternative as a restorative material. Cention N degree of conversion and flexural strength making it an esthetic option to amalgam.