Dental luting agents: A review of the current literature

Self-adhesive resin cement versus conventional cements on the failure rate of indirect single-tooth restorations: A systematic review and meta-analysis of randomized clinical trials

STATEMENT OF PROBLEM

Cementation is one of the most critical steps that influence the failure rates of indirect restorations. Self-adhesive resin cements arose out of the need for technical simplification of this procedure to reduce the risk of operative errors, with good acceptance by clinicians. How the failure rate of indirect single-tooth restorations cemented with self-adhesive resin cements compares with the failure rate of those cemented conventionally is unclear.

PURPOSE

The purpose of this systematic review and meta-analysis of randomized clinical trials was to compare self-adhesive resin cements versus conventional cements on the failure rates of indirect restorations.

MATERIAL AND METHODS

The review was registered at the International Prospective Register of Systematic Reviews (PROSPERO - CRD42020215577). The search strategy was adapted for 5 databases (PubMed, The Cochrane Library, EMBASE, Web of Science, and LILACS) and 1 nonpeer-reviewed literature source (clinicaltrials.gov). The strategy was guided by the problem/population, intervention, comparison, outcome (PICO) question: adults indicated for indirect restorations -P, self-adhesive resin cement -I, conventional cement-C, failure rates-O. The risk of bias was assessed using the Cochrane risk of bias (RoB2) tool and guidelines. Meta-analysis merged the results from included studies by pooling the hazard ratios and standard errors, available or estimated. The certainty of evidence was assessed by using the classification of recommendations, evaluation, development, and evaluation (GRADE) approach.

RESULTS

Nine randomized clinical trials were included in qualitative and quantitative analysis. Eight studies detected nonsignificant differences in failure rates between cements. Only 1 study reported a significantly higher failure rate on single-tooth ceramic crowns luted with self-adhesive resin cement. Nonsignificant differences were detected after the results from all studies had been pooled.

CONCLUSIONS

Based on clinical evidence, self-adhesive resin cements can be recommended for the cementation of indirect single-tooth restorations with a similar risk of failure to conventional cements.

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.

Comparative Evaluation of Luting Efficacy Between a Dual-Cure and Light-Cure Resin Cement on Its Application on Root Surface Indirect Restorations: An In Vitro Study

Aim The aim is to evaluate the degree of dye penetration between a dual-cure and conventional resin cement on its application on the root surface indirect restorations to provide a reference for clinical choice. Materials and methods Ten freshly extracted human maxillary central anteriors were selected and randomly divided into two groups of five each. Teeth were prepared for veneer restoration, and veneers were luted using two groups of cements Calibra veneer cement and Fusion Ultra D/C cement. After they were immersed in methylene blue dye solution for 24 h, the specimens were then sectioned buccolingual into three halves in a parallel vertical plane and measured dye penetration using a stereomicroscope (Zeiss). The data collected was recorded by the dye penetration index (0-4) and statistically analyzed using the IBM SPSS Statistics for Windows, Version 24 (Released 2016; IBM Corp., Armonk, New York, United States). Results It is evident that group 1 (Calibra veneer cement) showed the lowest mean score of 0.43 mm and group 2 (Fusion Ultra D/C) showed a highest mean score of 0.72 mm. Overall, when the two groups were compared for microleakage using SPSS, there was a significant difference among the groups. Conclusion It was determined that both the resin cements evaluated in this study showed microleakage to some level given the limits of the investigation and the findings. To evaluate the dye penetration of microleakage, the Calibra veneer resin cement showed a better marginal adaptability for veneer restoration. Further investigations with broader methodology and more clinical simulation are needed to evaluate other resin cements available for root surface indirect restorations to be analyzed for prospective clinical outcomes.

Cytotoxicity of dental cement on soft tissue associated with dental implants at different time intervals

Background

To investigate and compare the effect of four commercially used dental cement at 24 hours, 48 hours,72 hours (h) and 6 days on the cellular response of human gingival fibroblast (HGF).

Methods

3 cement pellet samples were made for each 4-test cement (n=12). The cement used for this study were zinc phosphate (ZP), zinc oxide non-eugenol (ZOE), RelyX U200 (RU200), and glass ionomer cement (GIC). The cytotoxicity of peri-implant tissues was investigated using one commercial cell line. All processing was done following International Organization for Standardization (ISO) methods 10993-5 and 10993-12 (MTT assay Test). Cell cultures without dental cement were considered as control. Standard laboratory procedures were followed to permit cell growth and confluence over 48 hrs after sub-cultivation. Before being subjected to analysis, the cells were kept in direct contact with the cement samples for the suggested time period. To validate the results the specimens were tested three times each. Cell death and inhibition of cell growth were measured quantitatively. Results were analyzed using 1-way ANOVA (a=0.05) followed by Tukey B post hoc test.

Results

The study showed the dental cement test material was cytotoxic. ZOE, ZP, GIC, and RU200 were cytotoxic in decreasing order, respectively, significantly reducing cell viability after exposure to HGF (p <0.001).

Conclusions

Within the limitations of this in-vitro cellular study, results indicated that HGF were vulnerable to the test the dental cement. The highest cytotoxicity was observed in ZOE, followed by ZP, GIC, and RU200.

Resin cement selection for different types of fixed partial coverage restorations: A narrative systematic review

OBJECTIVE

The aim of this study was to review the selection criteria of resin cements for different types of partial coverage restorations (PCRs) and investigate if the type of restorations or restorative materials affect the type of selected resin cement.

MATERIALS AND METHODS

An electronic search (1991-2023) was performed in PubMed, Medline, Scopus, and Google Scholar databases by combinations of related keywords.

RESULTS

A total of 68 articles were included to review the selection criteria based on the advantages, disadvantages, indications, and performance of resin cements for different types of PCRs.

CONCLUSIONS

The survival and success of PCRs are largely affected by appropriate cement selection. Self-curing and dual-curing resin cements have been recommended for the cementation of metallic PCRs. The PCRs fabricated from thin, translucent, and low-strength ceramics could be adhesively bonded by light-cure conventional resin cements. Self-etching and self-adhesive cements, especially dual-cure types, are not generally indicated for laminate veneers.

Cytotoxicity of dental cement on soft tissue associated with dental implants at different time intervals

Background: To investigate and compare the effect of four commercially used dental cement at 24 hours, 48 hours,72 hours (h) and 6 days on the cellular response of human gingival fibroblast (HGF). Methods: 3 cement pellet samples were made for each 4-test cement (n=12). The cement used for this study were zinc phosphate (ZP), zinc oxide non-eugenol (ZOE), RelyX U200 (RU200), and glass ionomer cement (GIC). The cytotoxicity of peri-implant tissues was investigated using one commercial cell line. All processing was done following International Organization for Standardization (ISO) methods 10993-5 and 10993-12 (MTT assay Test). Cell cultures without dental cement were considered as control. Standard laboratory procedures were followed to permit cell growth and confluence over 48 hrs after sub-cultivation. Before being subjected to analysis, the cells were kept in direct contact with the cement samples for the suggested time period. To validate the results the specimens were tested three times each. Cell death and inhibition of cell growth were measured quantitatively. Results were analyzed using 1-way ANOVA (a=0.05) followed by Tukey B post hoc test. Results: The study showed the dental cement test material was cytotoxic. ZOE, ZP, GIC, and RU200 were cytotoxic in decreasing order, respectively, significantly reducing cell viability after exposure to HGF (p <0.001). Conclusions: Within the limitations of this in-vitro cellular study, results indicated that HGF were vulnerable to the test the dental cement. The highest cytotoxicity was observed in ZOE, followed by ZP, GIC, and RU200.

Effect of Three Different Liquid Medias in the Sorption and Solubility of Luting Cements: An In Vitro Study

Background Among the various mechanical and biological properties of luting cement, the most important are its resistance to disintegration, degradation, and stability in the oral cavity. The sorption and solubility of cement alter the mechanical properties by impeding the half-life of the filling. It also leads to variations in dimensions, discoloration, and margin breakage. It is, therefore, essential to choose a low-solubility cement since there is always an interaction between teeth and restorative margins. The aim of this study is to assess and compare the solubility and sorption values of three different luting cements in three liquid media. Materials and methods Three luting cements were used for the investigation. Disc-shaped specimens of the cement, which were of 10 mm diameter and 2 mm height, were prepared. The sample included a total of 126 disc-shaped specimens made up of three materials, glass ionomer cement (GIC), resin cement, and resin-modified GIC, which were used in three liquid media (14 of each material in each medium). Fourteen specimens of each material were placed in glass vials containing 20 ml of each medium: distilled water, artificial saliva, and carbonated water. The samples were then put in an incubator at 37 °C. The measurements and masses of the samples were documented on days one, three, seven, 14, 21, 28, and 35. The samples were taken out of the solution after five weeks and stored in a desiccator with calcium sulphate for another five weeks. The weight and dimensional changes were estimated on days one, three, seven, 14, 21, 28, and 35. The values of water sorption (WSO) and solubility (WSL) were estimated. To determine the mean and standard deviation of each cohort, descriptive statistics were employed. Utilizing the Shapiro-Wilkinson test, the normality was determined. An independent test was used to determine the difference between all pairs of groups, while one-way ANOVA, Dunn test, and post hoc analysis were used to establish the distinction between the three groups. Results One-way ANOVA showed that significant differences existed among the groups: resin cement showed the least sorption and solubility, resin-modified GIC showed the highest solubility in distilled water (0.40 ± 0.03), and GIC showed the highest solubility in both artificial saliva (0.36 ± 0.03) and carbonated water (0.04 ± 0.05). Conclusion Considering the experimental outcomes and the limitations of an in vitro investigation, it was concluded that in the complex setting of the oral environment, this selection procedure is crucial for maintaining mechanical strength and for the long lifespan of dental restorations.

Knowledge of Saudi dental students and interns towards luting cements and their applications in fixed prosthodontics

BACKGROUND

Enhancement of students' knowledge is essential in improving their clinical skills and performance. Thus, the curriculum should be prepared to achieve a better outcome. The current study aimed to determine the dental students' and interns' basic knowledge towards dental luting cements and their application in dental practice to improve the theoretical and clinical training sections.

MATERIALS AND METHODS

A cross-sectional study was conducted among dental students and interns at three Colleges of Dentistry in the Kingdom of Saudi Arabia between September 2019-June 2020. An online questionnaire was used which included demographic data, questions about luting cement usage, cementation techniques, and commonly used cements in dental clinics. Descriptive analysis and chi-square test were used to show the association between level of dental education and the use of dental cements using SPSS software. The significance level was set at 5%.

RESULTS

The total respondents were 626 dental students/interns of whom 78.8% were undergraduate dental students. Participants who reported undergraduate studies as the source of information were 79.7%. The type of restoration was the main factor in luting cement selection (62.6%). Concerning the isolation technique in cementing laminate veneers, 49.7% used dri-angles, cotton rolls and saliva ejectors. Dual-cure resin cement was the most common cement used in all the mentioned restorations except in pressed porcelain laminate veneers and cement-retained implant-supported restorations.

CONCLUSIONS

Students' knowledge and practice in managing dental implants and porcelain laminate veneers need to be improved. The selection of a luting agent for a given restoration by students and interns was based on the basic knowledge, available cement, and the type of restoration. Awareness towards the management of short prepared teeth and custom-made cast posts and cores is also limited.

Comparison of the clinical outcomes of resin-modified glass ionomer and self-adhesive resin cementations for full-coverage zirconia restorations

OBJECTIVES

Both resin-modified glass ionomer cement (RMGIC) and self-adhesive resin cement (SAC) may be suitable for cementation of full-coverage zirconia restorations. This retrospective study aimed to investigate the clinical outcomes of zirconia-based restorations cemented with RMGIC and compare them with those cemented with SAC.

METHODS

Cases of full-coverage zirconia-based restorations cemented with either RMGIC or SAC between March 2016 and February 2019 were evaluated in this study. The clinical outcomes of the restorations were analyzed according to the type of cement used. In addition, cumulative success and survival rates were evaluated according to the cement and abutment types. Non-inferiority, Kaplan-Meier, and Cox hazard tests were conducted (α=.05).

RESULTS

A total of 288 full-coverage zirconia-based restorations (natural teeth, 157; implant restorations, 131) were analyzed. Loss of retention occurred in only one case; a single-unit implant crown cemented with RMGIC, which decemented 4.25 years post-restoration. RMGIC was non-inferior to SAC in terms of loss of retention (<5%). For single-unit natural tooth restorations, the four-year success rates in the RMGIC and SAC groups were 100% and 95.65%, respectively (p=.122). For single-unit implant restorations, the four-year success rates in the RMGIC and SAC groups were 95.66% and 100%, respectively (p=.365). The hazard ratios of all the predictor variables, including cement type, were not significant (p>.05).

CONCLUSIONS

Cementation of full-coverage zirconia restorations of both natural teeth and implants using RMGIC and SAC yields satisfactory clinical outcomes. Furthermore, RMGIC is non-inferior to SAC in terms of cementation success.

CLINICAL SIGNIFICANCE

Cementation with RMGIC or SAC for full-coverage zirconia restorations has favorable clinical outcomes in both natural teeth and implants. Both RMGIC and SAC have advantages in the cementation of full-coverage zirconia restorations to abutments with favorable geometries.

Microcomputed tomography void analysis after cement cleanup methods

STATEMENT OF PROBLEM

Cement at the restorative margin after implementation of the manufacturer's recommended procedure for cement cleanup has not been extensively evaluated.

PURPOSE

The purpose of this in vitro study was to use microcomputed tomography (μCT) to evaluate the number, volume, and width of voids left at the margin when dental cement is cleaned during the cementation process as per 2 manufacturer-prescribed methods for cement cleanup by evaluating a self-adhesive resin cement and a resin-modified glass ionomer cement.

MATERIAL AND METHODS

Twenty molar Ivorine Typodont prepared teeth were scanned, and lithium disilicate crowns were milled and cemented to the prepared teeth as per the manufacturer-recommended cementation process. Two methods of cement cleanup were performed: the excess cement was tack-polymerized with a polymerization light, or a delay of 3 minutes was used for the excess cement to reach partial polymerization, and the excess cement was removed with a sharp sickle scaler. These 2 methods of cement cleanup were performed with 2 cements: a resin-modified glass ionomer cement and a self-adhesive resin. Each specimen was then scanned with a μCT machine. The buccal margin of each specimen, from mesiobuccal line angle to distobuccal line angle, was examined, and the number, volume, and width of any voids remaining at the margin open to the environment were measured. For statistical analysis, the specimens were first grouped by method of cement cleanup and then grouped by cement type. The Wilcoxon ranked sum test was implemented because of the lack of a normal distribution and the heterogeneity of the data (α=.05).

RESULTS

No statistically significant difference was found in the median number of voids, median volume of voids, or median width per void between the 2 cleanup methods, irrespective of cement type (P>.05). Significant differences were found in the median number of voids, median volume of voids, and median width per void when comparing cement types, irrespective of cement cleanup methods (P<.05).

CONCLUSIONS

The choice of cement may be more important than the method of cement cleanup when considering voids left at the margin. Microcomputed tomography is an excellent nondestructive tool for volumetric measurements of voids at the margin.

Dental Luting Cements: An Updated Comprehensive Review

The cementation of indirect restoration is one of the most important steps in prosthetic and restorative dentistry. Cementation aims to bond the prosthetic restoration to the prepared enamel or enamel and dentine. Successful cementation protocols prevent biofilm formation at the margin between tooth and restoration and minimize mechanical and biological complications. With the advancements in dental cements, they have been modified to be versatile in terms of handling, curing, and bond strengths. This review presents updates on dental cements, focusing on the composition, properties, advantages, limitations, and indications of the various cements available. Currently, dental restorations are made from various biomaterials, and depending on each clinical case, an appropriate luting material will be selected. There is no luting material that can be universally used. Therefore, it is important to distinguish the physical, mechanical, and biological properties of luting materials in order to identify the best options for each case. Nowadays, the most commonly used dental cements are glass-ionomer and resin cement. The type, shade, thickness of resin cement and the shade of the ceramic, all together, have a tangible influence on the final restoration color. Surface treatments of the restoration increase the microtensile bond strength. Hence, the proper surface treatment protocol of both the substrate and restoration surfaces is needed before cementation. Additionally, the manufacturer's instructions for the thin cement-layer thickness are important for the long-term success of the restoration.

Update on Dental Luting Materials

A dental luting material aids in the retention and stability of indirect restorations on the prepared tooth structure. In dentistry, clinicians are using a wide range of luting materials for the cementation of indirect restorations. Zinc oxide eugenol and non-eugenol cements, zinc phosphate cement, zinc polycarboxylate cement, glass ionomer cement and resin cements are common dental cements used in dentistry. Each luting material or cement possesses unique properties and clinical implications. An ideal luting cement should be biocompatible, insoluble, resistant to thermal and chemical assaults, antibacterial, aesthetic, simple and easy to use. It should have high strength properties under tension, shear and compression to resist stress at the restoration-tooth interface, as well as adequate working and setting times. So far, no luting material possesses all of these properties of an ideal cement. Scientists have been modifying the conventional luting cements to improve the material's clinical performance and developing novel materials for clinical use. To achieve the best clinical outcome, clinicians should update their knowledge and gain a good understanding of the luting materials so that they can make a wise clinical decision on the material selection and obtain an insight into the development of luting cements. Therefore, the objective of this study is to provide a discussion on the physical, chemical, adhesive and aesthetic properties of common luting materials. The clinical indications of these luting materials are suggested based on their properties. In addition, overviews of the modification of the conventional luting materials and the newly developed luting materials are provided.

Current Protocols for Resin-Bonded Dental Ceramics

Resin-bonded ceramic restorations are common treatment options. Clinical longevity of resin-bonded ceramic restorations depends on the quality and durability of the resin-ceramic bond. The type and composition of the specific ceramic determines the selection of the most effective bonding protocol. Such protocol typically includes a surface pretreatment step followed by application of a priming agent. Understanding of fundamental ceramic properties and chemical compositions enables the clinician to make proper material selection decisions for clinically successful and long-lasting restorations. Based on research accrued over the past decades, this article reviews and discusses current resin-bonding protocols to most commonly used dental ceramics.

Novel antibacterial low-shrinkage-stress resin-based cement

OBJECTIVE

A low-shrinkage-stress resin-based cement with antibacterial properties could be beneficial to create a cement with lower stress at the tooth-restoration interface, which could help to enhance the longevity of the fixed dental restoration by reducing microleakage and recurrent caries. To date, there has been no report on the development of a low-shrinkage-stress and bio-interactive cement. Therefore, the objectives of this study were to develop a novel low-shrinkage-stress resin-based cement containing dimethylaminohexadecyl methacrylate (DMAHDM) and investigate the mechanical and antibacterial properties for the first time.

METHODS

The monomers urethane dimethacrylate (UDMA) and triethylene glycol divinylbenzyl ether (TEG-DVBE) were combined and denoted as UV resin. Three cements were fabricated: (1) UV+ 0%DMAHDM (experimental control); (2) UV+ 3%DMAHDM, (3) UV+ %5DMAHDM. RelyX Ultimate cement was used as commercial control. Mechanical properties and Streptococcus mutans (S. mutans) biofilms growth on cement were evaluated.

RESULTS

The novel bio-interactive cement demonstrated excellent antibacterial and mechanical properties. Compared to commercial and experimental controls, adding DMAHDM into the UV cement significantly reduced colony forming unit (CFU) counts by approximately 7 orders of magnitude, metabolic activities from 0.29 ± 0.03 A₅₄₀/cm² to 0.01 ± 0.01 A₅₄₀/cm², and lactic acid production from 22.3 ± 0.74 mmol/L to 1.2 ± 0.27 mmol/L (n = 6) (p < 0.05). The low-shrinkage-stress cement demonstrated a high degree of conversion of around 70 %, while reducing the shrinkage stress by approximately 60%, compared to a commercial control (p < 0.05).

CONCLUSIONS

The new antibacterial low-shrinkage-stress resin-based cement provides strong antibacterial action and maintains excellent mechanical properties with reduced polymerization shrinkage stress.

CLINICAL SIGNIFICANCE

A low-shrinkage-stress resin-based cement containing DMAHDM was developed with potent antibacterial effects and promising mechanical properties. This cement may potentially enhance the longevity of fixed dental restoration such as a dental crown, inlay, onlay, and veneers through its excellent mechanical properties, low shrinkage stress, and strong antibacterial properties.

Incorporation of chlorhexidine in self-adhesive resin cements

The aim of this study was to evaluate the maximum amount of chlorhexidine (CHX) that could be incorporated to self-adhesive resin cements to add antibacterial effect without affecting the physical properties. The CHX was incorporated into a commercial self-adhesive resin cement at mass fractions of 0.5-15 wt%, and the CHX-release profile, antibacterial effect, flexural and bond strengths of experimental cements were evaluated. Increasing the CHX content from 5 to 15 wt% resulted in a higher released concentration of CHX. In agar diffusion tests, experimental cements containing 5, 10, and 15 wt% CHX produced inhibition zones against oral bacteria. In flexural strength and shear bond strength to dentin, no significant reduction was observed with the incorporation of 5 wt% CHX. This in vitro study suggests that the addition of 5 wt% CHX yielded an antibacterial self-adhesive cement and had no adverse effect on the flexural and shear bond strengths.

Novel Rechargeable Nanostructured Calcium Phosphate Crown Cement with Long-Term Ion Release and Antibacterial Activity to Suppress Saliva Microcosm Biofilms

OBJECTIVE

Resin cements with remineralizing and antibacterial properties are favorable for inhibition of caries. The objectives of this study were: (1) to investigate the capability of the novel dimethylaminohexadecyl-methacrylate (DMAHDM) and nano-sized amorphous calcium phosphate (NACP) containing cement to reduce saliva microcosm biofilm, and (2) to investigate the long-term ion release, recharge, and re-release of DMAHDM-NACP cement.

METHODS

Pyromellitic glycerol dimethacrylate (PMGDM) and ethoxylated bisphenol-A-dimethacrylate (EBPADMA) were used to make PEHB monomer. Five cements were fabricated: (1) PEHB+0%NACP+0%DMAHDM (experimental control); (2) PEHB+25%NACP+0%DMAHDM, (3) PEHB+25%NACP+0%DMAHDM; (4) PEHB+25%NACP+3%DMAHDM; (5) PEHB+25%NACP+5%DMAHDM. RelyX luting cement was used as commercial control. Colony-forming units (CFU), lactic acid production, metabolic activities, and minimum inhibitory concentration (MIC) were performed. Long-term Calcium (Ca) and phosphate (P) ion release, recharge, and re-release were assessed.

RESULTS

Compared to experimental and commercial controls, the NACP-DMAHDM cement significantly reduced CFU biofilm by 2-3 orders of magnitude, metabolic activities from 0.24±0.06 A₅₄₀/cm² to 0.03±0.01 A₅₄₀/cm², and lactic acid production from 27.7±2.5 mmol/L to 5.4±2.1 mmol/L (n=6) (p<0.05). The DMAHDM showed an MIC value of 0.03 mg/L. However, when the DMAHDM was combined with PMGDM monomer, the MIC was greater than DMAHDM alone. The ion concentrations for the experimental groups significantly increased over time (1-84 days), indicating continuous ion release (n=3) (p<0.05). Increasing the DMAHDM mass fraction from 0% to 5% and 3% to 5% significantly enhanced ion recharge and re-release at the third cycle (p<0.05).

CONCLUSIONS

Incorporating DMAHDM and NACP into resin-based crown cement provides strong antibacterial action against saliva microcosm biofilm and presents a high level of Ca and P ion recharge abilities, exhibiting long-term Ca and P ion release and remineralization potential.

CLINICAL SIGNIFICANCE

Resin based cement containing NACP and DMAHDM were developed with remineralizing and potent antibacterial effects. This cement formulation showed ion release and remineralization potential and are promising formulations to inhibit the incidence of recurrent caries and could promote remineralization and be sustainable for the long term.

Shear bond strengths of two newly marketed self-adhesive resin cements to different substrates: A light and scanning electron microscopy evaluation

The purpose of this in vitro study was to compare the shear bond strengths (SBSs) of two newly marketed self-adhesive resin cements (RCs) to enamel, dentin, and lithium disilicate (LiSi) glass ceramic block. Forty-eight enamel and 48 dentin substrates were obtained from sound human molars. Additionally, 6 × 7 × 5 -mm- sized 24 specimens were produced from LiSi glass ceramic blocks. The tooth specimens were randomly assigned into four groups (n = 12) according to the surface treatments: (1) G-CEM ONE (GCO), (2) G-CEM ONE Adhesive Enhancing Primer (GCO-AEP) + GCO, (3) RelyX Universal (RXU), and (4) Scotchbond Universal Plus (SUP) + RXU. LiSi specimens were randomly divided into two groups (n = 12): (1) G-MultiPrimer (GMP) + GCO and (2) SUP + RXU. Following the RC applications, all specimens were kept in 100% humidity at 37°C for 24 hr and then submitted for SBS testing in a universal testing machine (1 mm/min). Data were analyzed by Welch's, one-way analysis of variance and two independent samples t tests. The nature of failures was examined under a light microscope, and scanning electron microscopy analyses were also performed for interfaces. GCO and RXU showed similar SBS to enamel (p > .05), and the use of adhesives resulted in improved SBS (p < .05). No difference was detected between GCO-AEP + GCO and SUP + RXU. The GCO-AEP + GCO exhibited the highest SBS to dentin (p < .05), followed by GCO ≥ SUP + RXU > RXU (p < .05). There was no significant difference between SBSs of two RCs to LiSi blocks (p > .05). No cohesive failure was determined for the tested groups by light microscope. The use of adhesives prior to the application of self-adhesive RCs improved their bonding to tooth tissues. GCO demonstrated superior SBS to dentin, whereas both self-adhesive RCs generated similar SBS to enamel and LiSi glass ceramic surfaces.

Investigating the mechanophysical and biological characteristics of therapeutic dental cement incorporating copper doped bioglass nanoparticles

OBJECTIVE

This study was investigated the mechanophysical properties of zinc phosphate cement (ZPC) with or without the copper doped bioglass nanoparticles (Cu-BGn) and their biological effect on dental pulp human cells and bacteria.

MATERIALS AND METHODS

Cu-BGn were synthesized and characterized firstly and then, the experimental (Cu-ZPC) and control (ZPC) samples were fabricated with similar sizes and/or dimensions (diameter: 4 mm and height: 6 mm) based on the International Organization of Standards (ISO). Specifically, various concentrations of Cu-BGn were tested, and Cu-BGn concentration was optimized at 2.5 wt% based on the film thickness and overall setting time. Next, we evaluated the mechanophysical properties such as compressive strength, elastic modulus, hardness, and surface roughness. Furthermore, the biological behaviors including cell viability and odontoblastic differentiation by using dental pulp human cells as well as antibacterial properties were investigated on the Cu-ZPC. All data were analyzed statistically using SPSS® Statistics 20 (IBM®, USA). p < 0.05 (*) was considered significant, and 'NS' represents nonsignificant.

RESULTS

Cu-BGn was obtained via a sol-gel method and added onto the ZPC for fabricating a Cu-ZPC composite and for comparison, the Cu-free-ZPC was used as a control. The film thickness (≤ 25 µm) and overall setting time (2.5-8 min) were investigated and the mechanophysical properties showed no significance ('NS') between Cu-ZPC and bare ZPC. However, cell viability and odontoblastic differentiation, alkaline phosphate (ALP) activity and alizarin red S (ARS) staining were highly stimulated in the extracts from the Cu-ZPC group compared to the ZPC group. Additionally, the antibacterial test showed that the Cu-ZPC extracts were more effective than the ZPC extracts (p < 0.05).

SIGNIFICANCE

Cu-ZPC showed adequate mechanophysical properties (compressive strength, hardness, and surface roughness) and enhanced odontoblastic differentiation as well as antibacterial properties compared to the ZPC-only group. Based on the findings, the fabricated Cu-ZPC might have the potential for use in the field of dental medicine and clinical applications.

Cement selection criteria for full coverage restorations: A comprehensive review of literature

BACKGROUND

Proper cement selection in fixed prosthesis plays a determinative role in providing long-term serviceability, retention, caries prevention, and patient satisfaction. This study, reviews different luting agent characteristics and their application based on different clinical situations and different types of full coverage restorations.

MATERIAL AND METHODS

An electronic search was conducted through PubMed, Medline, and Google scholar using following keywords or combinations: restoration, full coverage, PFM, porcelain fused to metal, all ceramic, zirconia, ceramic, casting, fixed partial denture, cement*, dental cement, cement selection, and retention. The most related articles were selected for review.

RESULTS

Choosing a proper luting agent is highly dependent on scientific knowledge regarding the characteristics of restorative materials and luting agents. Conventional cements could be indicated in various situations; however, some restorative materials or clinical situations call for resin-cements to provide predictable retention, support, and durability.

CONCLUSIONS

Conscious selection of retentive cement for each type of restoration/material is necessary to provide predictable successful treatment and reduce the potential complications. Key words:Adhesive cement, dental bridgework, dental cements, dental crowns, dental porcelain, prostheses and implants.

The effect of functionalized titanium dioxide nanotube reinforcement on the water sorption and water solubility properties of flowable bulk-fill composite resins

The aim of this study was to investigate the effects of titanium dioxide nanotube addition on the water sorption and water solubility values of different composite resins. Titanium dioxide nanotubes were synthesized from titanium dioxide powder in anatase form and in 13 nm diameter by hydrothermal process and then functionalized with methacrylic acid. Characterization of the nanotubes was performed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction and Fourier transform infrared spectroscopy. A flowable composite resin (Filtek Ultimate Flowable) and four flowable bulk-fill composite resins (Filtek Bulk Fill Flowable, SDR Bulk Fill Flowable, Venus Bulk Fill, X-tra Base) were tested. Two groups of each composite resin were prepared: groups of the resins without nanotubes; groups of the resins reinforced with 1.0 wt% functionalized titanium dioxide nanotube. Sorption and solubility in water were assessed according to ISO 4049 standards after 1, 7, 14, 21 days immersion periods. Data were analyzed using Mann-Whitney U and Kruskal-Wallis H tests (p  <  0.05). Long cylindrical tubular structures with a diameter of 41.09-72.49 nm were observed in electron microscopy analysis. The band at 1636 cm^- 1 showed the existence of the vinyl (C=C) bond of methacrylic acid coordinated to the nanotubes in Fourier transform infrared spectroscopy analysis. None of the materials tested in this study exceeded the maximum sorption and solubility values established by ISO. Regarding the water solubility, negative values were obtained. TiO₂ nanotube reinforcement decreased the water sorption and solubility values significantly at different evaluation periods in all composite resins except for Venus (p < 0.05).

Evaluation of Color Changes of Different Resin Cements in Feldspathic Ceramic Crowns After Accelerated Aging: An In Vitro Research

Aims:

To evaluate the color changes that occur after accelerated aging in feldspathic ceramic crowns cemented with three different dual-cured resin cements.

Materials and Methods:

For each of the A2-colored RelyX U200, G-CEM LinkForce, and Panavia V5 cement groups, 45 dies from A2-colored zirconia blocks and 45 crowns from CEREC blocks were prepared. Color measurements after 24 h of cementation (T1) and after cycles of aging of 1750 (T2), 3500 (T3), and 7000 (T4) in the thermal cycle device were made using SpectroShade Micro device. The coordinates of the color were used L*, a*, and b* as base and the color change was calculated with ∆ E00 in determining the color. One-way analysis of variance test was used to compare the times in terms of ∆ L*, ∆ a*, and ∆ b* values.

Results:

It was found that ∆ L* value decreased significantly in period of the T2, T3, and T4 times compared to T1 in all groups ( P < .05), whereas the change between period of T2, T3, and T4 times was not significant ( P > .05). The ∆ a* value increased significantly in the period of T3 and T4 times compared to T1 in the only G-CEM LinkForce group, whereas the ∆ b* value increased significantly in the period of T4 time compared to T1 in the only Panavia V5 group. The changes in ∆ E00 values, which were observed in all period of times, were found to be between 0.43 and 1.04, 0.43 and 1.43, and 0.40 and 0.97 in RelyX U200, G-CEM LinkForce, and Panavia V5 groups, respectively.

Conclusion:

After accelerated aging, it was found that the color of all cements became darker and the G-CEM LinkForce group turned red and the Panavia V5 group turned yellow. However, it was found that the color changes that occurred were within clinically acceptable visible levels.

Effect of aging on color stability and bond strength of dual-cured resin cement with amine or amine-free self-initiators

This study aimed to evaluate the effect of aging on the color stability and bond strengths of dual-cured resin cements containing amine or amine-free self-initiators. Three dual-cured and one light-cured resin cements were used. The covered (by lithium disilicate ceramic disks) and uncovered groups (n=10) were included. Color measurements were tested after 24 h, 10,000 and 20,000 thermal cycles (TCs). Micro-shear bond strengths (µSBS) were tested after 24 h, 10,000 and 20,000 TCs, and failure modes were analyzed (n=14). Two-way ANOVA and Tukey's test were implemented for color difference (ΔE*_ab) and µSBS (α=0.05). The mean ΔE*_ab difference was significant among groups (p<0.001). The lowest ΔE*_ab values were obtained for dual-cured resin cement with amine-free self-initiators dual-cured cement after aging in all dual-cured resin cements, and the µSBS of the dual-cured resin cements on ceramic was significantly higher than that of the light-cured ones after aging (p<0.001).

Aspiration of the dental crown in an elderly patient

The aspiration of objects and foreign bodies requires quick and systematic care. During emergent orotracheal intubation, accidental dental crown release can cause a threat to the patient's life. This paper aimed to report a case of foreign body (dental prosthetic crown) aspiration and its management and discuss alternative approaches. An 81-year-old male patient, who was admitted to the hospital's intensive care unit (ICU) for meningitis, presented with altered consciousness, and decreased oxygen saturation. He underwent emergent orotracheal intubation. After intubation, chest radiography was performed to check for proper orotracheal tube positioning and lung expansion. The resultant images revealed the presence of a foreign body within the right lower lobe bronchus in the shape of a dental crown. The foreign body, intubation cannula and basket clamp were successfully removed, followed by reintubation of the patient. The foreign body was a prosthetic upper premolar dental crown (24). While care should be taken to avoid complications, if a foreign body is aspirated during emergent orotracheal intubation, endoscopic removal appears safe and effective. Careful creation, placement, maintenance, and preservation of prosthetic crowns are critically important in elderly patients.

Predictable 3D guided adhesive bonding of porcelain veneers using 3D printed trays

OBJECTIVE

This clinical report describes a novel digital technique to facilitate and improve the porcelain laminate veneers adhesive bonding procedure using a customized 3D printed guide.

CLINICAL CONSIDERATIONS

Porcelain veneers can be stabilized in their fully seated position with a digitally design 3D printed guide before the resin cement is polymerized. The excess cement can be carefully and predictably removed without the risk of dislodgement, rotation or misfit, allowing the clinician to light cure them under controlled pressure in the correct seating position without the risk of fracturing the ceramic material.

CONCLUSIONS

Fabricating a custom 3D printed guide for veneer bonding provides significant assistance to an otherwise cumbersome and daunting clinical procedure.

CLINICAL SIGNIFICANCE

Adhesive bonding of multiple ceramic veneers is a challenging and technique sensitive procedure. The use of a custom 3D printed guide presented in this article offers a practical aid to achieve a more predictable and precise outcome.

Masking of High-Translucency Zirconia for Various Cores

CLINICAL RELEVANCE

Various core materials with different shades affect the final color of high-translucency monolithic zirconia restorations. The blue core shows the greatest color difference in final zirconia restorations followed by metal, A3 dentin-shade resin core, and white core.

SUMMARY

The purpose of this study was to evaluate the masking ability of high-translucency monolithic zirconia for various core materials. A computer-aided design-computer-aided manufacturing system was used to design a zirconia disc with a diameter of 10 mm and a thickness of 1.0 mm. Four groups of cores (n=15 each) were fabricated with blue-colored dual-cure resin, white-colored dual-cure resin, A3 dentin-shade composite resin, and titanium block with 10-mm diameter and 5-mm thickness.Dual-cure, self-adhesive resin cement discs with a thickness of 25.0 ± 0.02 μm were fabricated. The color was measured using a handheld spectrophotometer. Color measurements of all specimens were performed on a white background. To assess the masking ability of zirconia, the difference between the values measured with zirconia on a white background and the values measured with zirconia on each of the four types of core material as a background with the cement specimens interposed (zirconia + cement + core) was determined. To enhance the optical connection between the specimens, distilled water was applied between each layer during each measurement.The results showed that the value of ΔE was highest for the blue core followed by metal, A3 dentin-shade resin core, and white-resin core. No significant differences were observed between the metal core and the A3 dentin-shade resin core or between the A3 dentin-shade resin core and the white core. The blue core had the significantly highest ΔE value based on Tukey's honest significant difference test.Different core materials affect the final color of high-translucency monolithic zirconia restorations. Thus, our study showed that the final color of high-translucency monolithic zirconia restorations could be affected by the type of core material used.

Comparative evaluation of microleakage of metallic copings luted with three different commercially available luting cements: An in vitro study

Aim

To evaluate the microleakage of metallic copings luted with three different commercially available luting cements.

Setting and Design

Comparative evaluation in vitro study.

Materials and Methods

Thirty replicas of abutment analog were milled and divided into 3 groups. Nickel chromium copings were fabricated; marginal gap was evaluated with optical microscope and luted with Zinc Oxide Non Eugenol cement, Zinc Polycarboxylate cement and Zinc Phosphate cement. After Thermocycling, cemented specimens were placed into 0.5% aqueous solution of basic fuchsin solution for 24 hours for dye penetration. Copings were longitudinally sectioned and microleakage scores were evaluated.

Statistical Analysis Used

Kruskal-Wallis analysis of variance (ANOVA) followed by Chi-Square test. Pairwise comparison of groups with Mann Whitney U test.

Result

Mean microleakage score was least for Zinc Phosphate cement (1.075 ± 0.85) followed by Zinc Polycarboxylate cement (1.80± 0.23) and most for Zinc Oxide Non Eugenol (2.1± 0.37). The results of the study were statistically significant, P < 0.05.

Conclusions

Within the limitations of the study, it was found that all cements exhibited certain amount of microleakage. Zinc Phosphate cement exhibited a mean microleakage score that was significantly lower than Zinc Oxide Non Eugenol cement and Zinc Polycarboxylate cement. When microleakage scores of Zinc Oxide Non Eugenol cement and Zinc Polycarboxylate cement were compared, the difference was found to be insignificant indicating that microleakage in these cements is similar.

Comparative Analysis of Static and Viscoelastic Mechanical Behavior of Different Luting Material Categories after Aging

The longevity of indirect restorations is primarily determined by the appropriate selection of the luting material. The function of a luting material is to seal the restoration and hold it in place for the time required for service. The mechanical behavior of luting materials and in particular their aging behavior, therefore, play a decisive role. The study provides a comparative analysis of the static and dynamic mechanical behavior of the most commonly used luting material categories-zinc phosphate cement, glass-ionomer cement, resin-modified glass-ionomer cement, resin-based composites, and self-adhesive resin-based composites-and their aging behavior. It also takes into account that luting materials are viscoelastic materials, i.e., materials that respond to external loading in a way that lies between an elastic solid and a viscous liquid. Flexural strength and modulus were determined in a three-point bending test followed by fractography analysis. The quasi-static and viscoelastic behavior was analyzed by a depth-sensing indentation test provided with a dynamic mechanical analysis (DMA) module at 20 different frequencies (1-50 Hz). The fracture toughness was evaluated in a notchless triangular prism (NTP) test. Material type exhibits the strongest influence on all measured properties, while the effect of aging becomes more evident in the material reliability. The variation of the viscoelastic parameters with aging reflects cement maturation or polymer plasticization.

Evaluation of radiopacities of CAD/CAM restorative materials and resin cements by digital radiography

OBJECTIVE

This study aims to compare the radiopacities of computer-aided design/computer-aided manufacture (CAD/CAM) blocks and the adhesive cements used for their bonding.

MATERIALS AND METHODS

1 ± 0.2 mm thick specimens were obtained from six different CAD/CAM blocks (Incoris TZI, IPS e.max CAD, Vita Mark II, Cerasmart, Vita Enamic, and Vita Suprinity), four different adhesive resin cements (Panavia F2.0, Variolink Esthetic DC, RelyX Unicem Aplicap, G-CEM LinkAce), and a tooth. Radiographs of the specimens from each group, a tooth section, and an aluminum (Al) step-wedge were acquired. The radiopacity values of the materials were calculated as equivalents of Al thickness using the gray level values. The data were statistically analyzed using one-way ANOVA and Tukey HSD tests.

RESULTS

All the materials except Cerasmart and Vita Enamic had significantly higher radiopacity values than dentin (p < 0.05). Of the assessed blocks, the highest radiopacity value was observed in Incoris TZI, and the lowest radiopacity value was observed in Vita Enamic. Variolink Esthetic DC and RelyX Unicem Aplicap showed significantly higher radiopacity (p < 0.05) than the other adhesive cements, including enamel and dentin.

CONCLUSIONS

In this study, the majority of the CAD/CAM materials and all the adhesive resin cements were found to have sufficient radiopacity for prosthetic restorations according to the criteria set by the International Organization for Standardization (ISO).

CLINICAL RELEVANCE

From a clinical and biological point of view, materials should be chosen according to their radiopacity and other properties, such as biocompatibility and esthetics. If the selected restorative CAD/CAM blocks have a radiopacity value less than or equal to dentin, cements with higher radiopacity values are recommended to facilitate radiological diagnoses for periphery and interface of restorations.

Shear Bond Strength and Film Thickness of a Naturally Antimicrobial Modified Dental Luting Cement

Although several natural plants and mixtures have been known and used over the centuries for their antibacterial activity, few have been thoroughly explored in the field of dentistry. Thus, the aim of this study was to enhance the antimicrobial activity of a conventional glass ionomer cement (GIC) with natural plant extracts. The effect of this alteration on the bond strength and film thickness of glass ionomer cement was evaluated and related to an 0.5% chlorohexidine modified GIC. Olive leaves (Olea europaea), Fig tree (Ficus carica), and the leaves and roots of Miswak (Salvadora persica) were used to prepare an alcoholic extract mixture. The prepared extract mixture after the evaporation of the solvent was used to modify a freeze-dried glass ionomer cement at three different extracts: water mass ratios 1:2, 1:1, and 2:1. An 0.5% chlorhexidine diacetate powder was added to a conventional GIC for the preparation of a positive control group (CHX-GIC) for comparison. The bond strength to dentine was assessed using a material-testing machine at a cross head speed of 0.5 mm/min. Failure mode was analyzed using a stereomicroscope at 12× magnification. The cement film thickness was evaluated in accordance with ISO standard 9917-1. The minimum number of samples in each group was n = 10. Statistical analysis was performed using a Kruskal–Wallis test followed by Dunn’s post hoc test for pairwise comparison. There was a statistically insignificant difference between the median shear bond strength (p = 0.046) of the control group (M = 3.4 MPa), and each of the CHX-GIC (M = 1.7 MPa), and the three plant modified groups of 1:2, 1:1, 2:1 (M = 5.1, 3.2, and 4.3 MPa, respectively). The CHX-GIC group showed statistically significant lower median values compared to the three plant-modified groups. Mixed and cohesive failure modes were predominant among all the tested groups. All the tested groups (p < 0.001) met the ISO standard of having less than 25 µm film thickness, with the 2:1 group (M = 24 µm) being statistically the highest among all the other groups. The plant extracts did not alter either the shear bond strength or the film thickness of the GIC and thus might represent a promising additive to GICs.

Novel Crown Cement Containing Antibacterial Monomer and Calcium Phosphate Nanoparticles

Oral biofilm accumulation at the tooth–restoration interface often leads to recurrent dental caries and restoration failure. The objectives of this study were to: (1) develop a novel bioactive crown cement containing dimethylaminohexadecyl methacrylate (DMAHDM) and nano-sized amorphous calcium phosphate (NACP), and (2) investigate the mechanical properties, anti-biofilm activity, and calcium (Ca²⁺) and phosphate (PO₄³⁻) ion release of the crown cement for the first time. The cement matrix consisted of pyromellitic glycerol dimethacrylate and ethoxylated bisphenol-A dimethacrylate monomers and was denoted PEHB resin matrix. The following cements were tested: (1) RelyX luting cement (commercial control); (2) 55% PEHB + 45% glass fillers (experimental control); (3) 55% PEHB + 20% glass + 25% NACP + 0% DMAHDM; (4) 52% PEHB + 20% glass + 25% NACP + 3% DMAHDM; (5) 51% PEHB + 20% glass + 25% NACP + 4% DMAHDM; (6) 50% PEHB + 20% glass + 25% NACP + 5% DMAHDM. Mechanical properties and ion release were measured. Streptococcusmutans (S. mutans) biofilms were grown on cements, and colony-forming units (CFUs) and other biofilm properties were measured. The novel bioactive cement demonstrated strong antibacterial properties and high levels of Ca²⁺ and PO₄³⁻ ion release to remineralize tooth lesions. Adding NACP and DMAHDM into the cement did not adversely affect the mechanical properties and dentin bonding strength. In conclusion, the novel NACP + DMAHDM crown cement has excellent potential for restoration cementation to inhibit caries by suppressing oral biofilm growth and increasing remineralization via Ca²⁺ and PO₄³⁻ ions. The NACP + DMAHDM composition may have wide applicability to other biomaterials to promote hard-tissue formation and combat bacterial infection.

Effect of Exclusive Primer and Adhesive on Microtensile Bond Strength of Self-Adhesive Resin Cement to Dentin

The aim of this study was to investigate the effect of G-CEM One Primer (GCOP) and self-etching adhesive on the microtensile bond strength (µTBS) between self-adhesive resin cement G-CEM One (GCO) and dentin. Teeth were sectioned to expose the flat dentin surface and randomly assigned into five groups (n = 15) according to the dentin surface treatment: 1) no surface treatment, 2) GCOP, 3) All-Bond Universal (ABU), 4) GCOP followed by ABU (GCOP/ABU), 5) ABU followed by GCOP (ABU/GCOP). The composite resin blocks were bonded to the dentin surface using GCO. The specimens were stored in distilled water at 37 °C for 24 h, then sectioned into sticks (1 mm × 10 mm). The μTBS values were statistically analyzed using 1-way analysis of variance (ANOVA) and Tukey’s honestly significant difference (HSD) test (α = 0.05) and failure mode was examined under a stereomicroscope. The bonding interface of each specimen was evaluated using confocal laser scanning microscopy. The GCOP group exhibited the highest µTBS value and there were no significant differences observed between GCOP, GCOP/ABU, ABU/GCOP groups (p > 0.05). The use of GCOP with GCO results in the improved µTBS between GCO and dentin. In conclusion, using only GCOP with GCO for bonding of indirect restoration is extremely simple and increasing bond strength.

Dentin bond strength of bioactive cement in comparison to conventional resin cement when photosensitized with Er,Cr:YSGG Laser

Objective:

The purpose of the present study was to assess dentin shear bond strength (SBS) and mode of bond failure of bioactive cement (BA) in comparison to conventional resin cement when photosensitized by Er,Cr: YSGG Laser (ECL).

Methods:

The present in-vitro study was carried out from March 2019 to May 2019. Sixty permanent non-carious, intact, non-fractured molars were isolated and mounted vertically in acrylic resin. Buccal surface of each molar tooth was ground, polished and surface treated with ECL. Ketac conditioner was applied on the surface washed and air dried surface. Tetric -N-Bond adhesive was applied on forty-five samples and light cured. The specimens were allocated into four groups (n=15) according to the type of cement used i.e., Calibra (C), BA, Variolink II (V) and Maxcem-Elite (ME). For SBS testing was performed using the universal testing machine. Eight samples from each group were assessed for modes of failure. Means and standard deviations were compared using analysis of variance (ANOVA) and Tukey’s post hoc test at a significance level of p < 0.05.

Results:

The highest mean SBS was observed in group ECL-C (21.55±3.08). The lowest mean SBS was displayed in group ECL-ME (14.25±3.55). Mean SBS values for group ECL-C (21.55±3.08) and group ECL-V (20.74±4.15) were comparable (p <0.05). Similarly, SBS values of group ECL-BA (15.48±3.62) and group ECL-ME (14.25±3.55) were comparable (p <0.05).

Conclusion:

Dentin surface conditioned with Er,Cr: YSGG and bonded to C and V cements exhibit favourable bond strength values.

Effect of different laser types on bonding strength of CAD/CAM-customized zirconia post to root canal dentin: an experimental study

In clinical dentistry, the strength of bonding zirconia posts to root canal dentinal walls currently needs enhancement, and laser application can be an important contribution owing to its features that accommodate adjustable modifications on dental materials. Herein, the effect of different laser treatments applied to dentin surfaces on the strength of bonding zirconia posts to root canal dentinal walls is evaluated by using the pull-out bond strength test in a laboratory setting. A total of 40 single-rooted permanent mandibular premolar teeth that were freshly extracted were used here. The root canal preparation steps were performed using the crown-down technique. Custom-made zirconia posts were produced using CAD/CAM technology. Prior to the application of resin cement, the internal surfaces of the root canals were irradiated using Nd:YAG, Er:YAG, and KTP lasers. Pull-out tests were performed on each specimen by using a universal testing machine. One-way analysis of variance and Tukey post hoc tests were used to compare the pull-out bond strength data. The bond strengths of the laser-treated specimens were greater than those of the untreated controls (p < 0.05). While the value of the pull-out bond strength after Nd:YAG laser treatment was significantly higher than the values obtained after the applications of the Er:YAG and KTP lasers (p < 0.05), the pull-out bond strength after Er:YAG laser treatment was considerably greater than that after KTP laser treatment (p < 0.05). The bond strength between the root canal dentin and the CAD/CAM custom-made zirconia post was improved upon using all the laser modalities in current laboratory settings, among which, application of the Nd:YAG laser was the most successful.

Effect of experimental resin cements containing thio-urethane oligomers on the durability of ceramic-composite bonded interfaces

Thio-urethane oligomers improve conversion and mechanical properties of resin cements. The objective of this study was to evaluate the effect of resin cements formulated with thio-urethane (TU) oligomers on microtensile bond strength (µTBS) of ceramics to composites subjected to thermal/mechanical cycling. Methods: BisGMA/UDMA/TEGDMA (50/30/20 wt%) containg 0 (control, EC) or 20 wt% aliphatic or aromatic thiourethane (HDDI and BDI, respectively) were mixed with CQ/amine (0.2/0.8 wt%) and 25 wt% 0.7um Ba glass. Rely X Ultimate (RU-3M ESPE) was used as the commercial control. The cements were sandwiched between ceramic (IPS e.max Press) and resin composite blocks (Filtek Supreme, 3 M-ESPE). Eight bonded blocks were produced per experimental group. Prior to bonding, ceramic surfaces were etched (20 s - 10% HF) and silanized. Composite surfaces were treated with Single Bond Universal (3 M ESPE). Specimens were stored for 24 h in distilled water at 37 °C, and then either tested immediately, or subjected to thermal (10,000, 5 °C and 55 °C) or mechanical cycling (300,000 cycles). Sticks (1 mm², average of 25 sticks per block) were cut and tested for µTBS (1.0 mm/min). Data were analyzed with two-way ANOVA/Tukey's test (α = 5%). Fracture surfaces were analyzed to determine failure modes. Results: The µTBS for HDDI and RU was significantly higher than BDI and EC cements. BDI led to significantly higher µTBS than EC after 24 h, Tc and Mf. µTBS decreased significantly after thermal/mechanical cycling for all groups. Failure modes were predominantly adhesive or mixed. Significance: The use of selected thio-urethane oligomers was able to increase the µTBS of composite-cement-ceramic specimens. Tc and Mf reduced µTBS for all resins cements.

Color Stability of Ceramic Veneers Luted With Resin Cements and Pre-Heated Composites: 12 Months Follow-Up

Abstract The objective was to evaluate the color stability of ceramic veneers luted with resin cements and pre-heated composite resins (60oC) for 12 months, and determine the degree of conversion (DC) of the luting agents. Two resin cements (AllCem Veneer, light-cured (LRC) and AllCem, dual-cured (DRC)] and three composite resins [Z100 (MNCR-minifilled), Herculite Classic (MHCR-micro-hybrid) and Durafill (MCCR-microfilled)] were used for cementing 0.8-mm-thick lithium-silicate glass-ceramic laminates (Suprinity, shade B2-HT, Vita) on bovine enamel (n=10). The specimens were stored at 37oC in distilled water. CIELab parameters were determined at 24h after luting (baseline), 7, 30, 90, 180 days and 12 months. Three specimens were prepared for DC evaluation, performed by micro-Raman spectroscopy. Data were analyzed by ANOVA and Tukey’s test (a=5%). For ΔEab and ΔE00, there were significant differences for luting material (p<0.001), time (p<0.001), and double interaction (p<0.001). The groups cemented with MHCR (1 year), MCCR (90 days and 1 year) and MCCR-PH (1 year) were the ones with ΔE values greater than the acceptability threshold. All other groups maintained their ΔE lower than the acceptability threshold after 1 year in distilled water. Regarding DC, there were no significant differences (p=0.127) among the materials. Non-significant negative correlations were observed between the mean ΔEab and DC (R=-0.65) and ΔE00 and DC (R=-0.64). A significant positive correlation was observed mean ΔEab and ΔE00 (R=0.99). It was concluded that the different luting agents influenced the final color of the restorations. The heating of the composite resins did not affect their DC.

Influence of two different cement space settings and three different cement types on the fit of polymer-infiltrated ceramic network material crowns manufactured using a complete digital workflow

OBJECTIVES

The study evaluates the influence of two spacer settings and three resin luting materials on the marginal and internal fit of polymer-infiltrated ceramic network (PICN) material crowns manufactured using a complete digital workflow.

METHODS

Optical impressions of fifty identical dies were performed using the 3M scanner (software version 5.0.2). Twenty crowns were designed using Ceramill Mind (version 3.4.10.1163), from which ten with spacer setting of 50 μm (G1) and ten with 80 μm (G2). Thirty crowns (spacer setting of 50 μm) were divided into three groups corresponding to the resin materials used as follows: RelyX Unicem (RX), Variolink Esthetic (VLE), and Nexus 3 (NX3). All crowns were milled from Vita Enamic blocks. After micro-CT scanning, absolute marginal discrepancy (AMD), internal gap (IG), total cement space volume (TCV), and marginal porosities (VP) were measured.

RESULTS

Significant difference was detected on the VP between the RX and NX3 group (p = 0.033). The mean values of all parameters were the following: AMD (μm): G1 182.6, G2 253.7, RX 210.8, VLE 195.5, NX3 186.6; IG (μm): G1 215.6, G2 173.1, RX 171.1, VLE 198.6, NX3 203; TCV (mm³): G1 22.9, G2 20.49, RX 17.57, VLE 17.49, NX3 20.59; VP (mm³): G1 0.26, G2 0.34, RX 0.32, VLE 0.46, NX3 0.54.

CONCLUSIONS

Fit of PICN material crowns was not significantly influenced by increasing the spacer settings and cementation with different resin materials. Additionally, RelyX Unicem showed significantly less porosities as compared with Nexus3.

CLINICAL RELEVANCE

Both 50 μm and 80 μm virtual spacer settings can be suggested for the manufacture of PICN crowns when Ceramill Mind (version 3.4.10.1163) is used. Furthermore, a self-adhesive system can be recommended for the cementation.

A Review of Dental Cements

This review provides an in-depth comparison of advantages and disadvantages of different types of dental cements as they are used for cementing base metal alloy crowns in dogs.

What is the Best Available Luting Agent for Implant Prosthesis?

Cement-retention is a viable option in restoring dental implants. A wide range of dental cements with different properties are commercially available for use in the cementation of implant prostheses. The selection of a dental cement for proper clinical application can be challenging. This article overviews the commercially available dental cements used in cement-retained implant-supported prostheses. Guidelines for cement selection are presented according to abutment and prosthetic material. Cementation techniques to reduce excess cement in peri-implant tissues are also mentioned.

In vitro retention efficiency of temporary type zinc oxide cement for orthodontic forced eruption

OBJECTIVE

To assess the retention efficiency of three types of temporary zinc oxide cement trademarks on forced eruption using intracranal wire device.

METHODS

An in vitro evaluation included intracanal wire device displacement and detachment at 50g load force for 120 days and then the retention resistance at maximum load force.

RESULTS

All groups of temporary zinc oxide cements were efficient to support 50g load forces after 120 days. None statistical differences were found between groups. Zinc oxide cements supported a maximum retention load force, which exceeded in more than 84 times the lowest value obtained in controls (420g).

CONCLUSION

Zinc oxide cements are efficient to retain intracanal wire devices on forced eruption processes in vitro and allows removal of both when necessary (wire device and cement, respectively).

Effect of cementation, cement type and vent holes on fit of zirconia copings

Objectives

To investigate the effect of cementation, cement type and vent-holes on the marginal and internal fit of Zirconia (Zr) Copings.

Materials and methods

Extracted premolars (N = 100) were mounted in resin and prepared for Zr crowns. Samples were randomly divided into 5 groups (n = 20); A: No Cementation; B: Cementation with Glass-Ionomer (GI); C: GI + Vent-Holes; D: Cementation with Resin Cement (RC); E: RC + Vent-Holes. The copings were fabricated using semi sintered Zr Blocks with a standardized cement space of 20 µm. Groups C & E were designed to have 0.5 mm of Vent-Holes on the Buccal and Lingual Cusp Tips. The copings were tried, cemented, thermocycled, re-embedded in resin and cross sectioned into two halves. The copings were examined with 3D-Digital Microscope (HIROX, KH-7700, Tokyo, Japan) at 50-200X. The gaps were recorded at 9 predetermined points.

Results

The non-cemented groups showed statistically better fit compared to the cemented groups P < 0.05 except vs Group E (RC plus vent holes). No significance was found between the cemented groups P > 0.05. Copings with vent-holes showed statistically better fit than copings without holes P < 0.05.

Conclusion

Marginal and Internal gap values designed in the software programs differed than the actual values measured for the non-cemented copings. Cementation process also influenced the fit of the Zr copings, the resin cement being the more accurate. The addition of vent-holes on the occlusal surface improved the fit.

The Retentive Strength of Laser-Sintered Cobalt-Chromium-Based Crowns after Pretreatment with a Desensitizing Paste Containing 8% Arginine and Calcium Carbonate

The retention of laser-sintered cobalt-chromium (Co-Cr)-based crowns were examined after dentin pretreatment with desensitizing paste containing 8% arginine and calcium carbonate (DP-ACC). Forty lower first molars were prepared using a standardized protocol. The Co-Cr crowns were produced using selective laser melting. The teeth were either pretreated with the desensitizing paste or not pretreated. After one week, each group was cemented with glass ionomer cement (GIC) or zinc phosphate cement (ZPC). Surface areas of the teeth were measured before cementation. After aging, a universal testing machine was used to test the retentive strength of the cemented crown-tooth assemblies. The debonded surfaces of the teeth and crowns were examined at 2.7× magnification. Pretreating the dentin surfaces with the desensitizing paste before cementation with GIC or ZPC did not affect the retention of the Co-Cr crowns. The retention of the GIC group (6.04 ± 1.10 MPa) was significantly higher than that of the ZPC group (2.75 ± 1.25 MPa). The predominant failure mode for the ZPC and the nontreated GIC group was adhesive cement-dentin failure; for the treated GIC group, it was adhesive cement-crown failure. The desensitizing paste can be safely used to reduce post-cementation sensitivity without reducing the retentive strength of Co-Cr crowns cemented with GIC or ZPC.

Effects of dynamic aging on the wear and fracture strength of monolithic zirconia restorations

Background

The purpose of this study is to evaluate the wear and fracture strength of crowns and three-unit partial fixed dental prosthesis (FDP) fabricated using by Bruxzir and Incoris TZI as recently introduced monolithic zirconia materials.

Methods

A total of sixteen crowns and sixteen three-unit FDPs were fabricated using Bruxzir and Incoris TZI (n = 8). All specimens were subjected to a 2-body wear test in a dual axis chewing simulator for 1,200,000 loading cycles against steatite antagonist balls. The fracture strength and volumetric loss were recorded. The obtained data were statistically analyzed by 2-way ANOVA testing (α = 0.05).

Results

The mean volumetric loss of the crowns was higher than that of the three-unit FDPs (p < 0.05). Of the two monolithic systems, Incoris TZI exhibited more wear than Bruxzir. The fracture strengths of Bruxzir crowns and FDPs were found to be higher than those of the crowns and FDPs fabricated with Incoris TZI (p < 0.05).

Conclusion

In in vitro test conditions, Bruxzir and Incoris TZI monolithic zirconia systems are fracture-resistant for the crown and FDP application against physiologic chewing forces owing to dynamic aging. Among newly developed monolithic zirconia materials, Bruxzir is found to be more resistant to fracture compared to the Incoris TZI.

Retention failures in cement- and screw-retained fixed restorations on dental implants in partially edentulous arches: A systematic review with meta-analysis

PURPOSE

This systematic review aimed to evaluate retention failures in cement- and screw-retained fixed restorations on dental implants in partially edentulous arches.

METHODS

The relevant articles were retrieved from MEDLINE (PubMed), Cochrane Library, and EBSCO electronic databases for articles published from January 1995 to January 2016 and were restricted to randomized controlled trials and retrospective and prospective studies on human subjects that were reported in English. A further hand search was conducted on individual journals and reference list of the articles found. Reviewed studies which reported retention failures in fixed implant-supported prostheses using screw and cement retention mechanism. Information on the type and nature of restoration, as well as different luting cement, were also collected.

RESULTS

Thirty-three articles were finalized, 20 short-term clinical studies (up to 5 years) and 13 long-term studies (≥5 years). Out of 33 studies, 16 studies were included in meta-analysis, 8 in short-term and 8 in long-term studies. The results of the meta-analysis for short-term studies showed statistically significant difference between cement-retained and screw-retained prosthesis, with the forest plot favoring cement-retained prostheses (risk ratio [RR]: 0.26; confidence interval [CI]: 0.09-0.74; P < 0.0001; I2 = 79%). In long-term studies, the forest plot revealed statistically significant difference between both retention systems favoring cement-retained prostheses (RR: 0.31; CI: 0.13-0.76; P = 0.03; I2 = 56%).

CONCLUSION

Analysis of the short- and long-term studies shows lesser retention failures with cement-retained prostheses when compared to screw-retained prostheses. Further, multicentric, high-quality randomized controlled studies with long-term observations and modified cementation protocols can yield higher grades of recommendation to avoid retention failures.

The effect of hydrofluoric acid and resin cement formulation on the bond strength to lithium disilicate ceramic

To investigate how the hydrofluoric acid (HF) concentrations applied to a lithium disilicate glass-ceramic (EMX) affects the surface morphology and microtensile bond strength (μTBS) of ceramics to dentin, using light-cured resin cements with or without UDMA. Sixty-three EMX square ceramic blocks were etched for 20 seconds using different HF concentrations (1%, 5% and 10%) and luted to dentin using two types of resin cement combinations: BisGMA/TEGDMA and BisGMA/TEGDMA/UDMA (n = 10). Each bonded EMX-dentin block was sectioned to obtain 1 mm2 sticks for μTBS evaluation. Half of the sticks were tested after 24 hours and the other half was assessed after 6 months of water storage. Data were statistically assessed using split-plot three-way ANOVA and multiple comparisons were performed using the Tukey's post hoc test (α = 0.05). One EMX sample from each HF concentration was analyzed using field-emission scanning electron microscope (FE-SEM) to characterize the etching pattern. According to the FE-SEM images, increasing the concentration of HF from 1 to 5 and then to 10% led to increased removal of glassy matrix and greater exposure of lithium disilicate crystals. The 10% HF concentration yielded higher μTBS when compared to 1% for BisGMA/TEGDMA formulation (p < 0.05); whereas HF 1% and 5% showed similar μTBS values when compared to 10% HF for BisGMA/TEGDMA/UDMA resin matrix (p > 0.05) at both storage times. Water aging decreased the μTBS values (p < 0.05), except when 10% HF was associated with BisGMA/TEGDMA resin cement. Resin cement formulation and hydrofluoric acid concentrations can interfere with the immediate and long-term glass-ceramic bond strength to dentin.