Comparative evaluation of compressive and flexural strength, fluoride release and bacterial adhesion of GIC modified with CPP-ACP, bioactive glass, chitosan and MDPB

Background. This study evaluated the incorporation of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), calcium sodium phosphosilicate bioactive glass (BAG), chitosan (CH), and methacryloyloxydodecylpyridinium bromide (MDPB) on the compressive and flexural strength, fluoride (F^‒ ) release, and bacterial adhesion of conventional glass-ionomer cement (C-GIC).

Methods. Modifications were implemented by adding CPP-ACP, BAG, and CH to the glass powder, while MDPB-GIC was prepared by incorporating MDPB to the liquid of C-GIC. Custom-made molds were used for specimen preparation. Compressive and flexural strengths were evaluated using a universal testing machine. F^‒ release was calculated with Erichrome cyanide reagent, using UV-spectrophotometry, at two time intervals of 24 hours and seven days. For bacterial adhesion, the test specimens were exposed to the bacterial suspension of Streptococcus mutans and Lactobacillus acidophilus for 4 hours, and the adherent bacteria were quantified using colorimetry as the optical density (OD).

Results. The incorporation of MDPB increased the flexural strength of C-GIC, with no effect on its compressive strength. CH significantly improved the compressive and flexural strength; modifications with CPP-ACP, BAG, and MDPB significantly improved the flexural strength of C-GIC. While MDPB-GIC released significantly higher F^‒ at 24 hours, CPP-ACP- and BAG-modified GICs were comparable to C-GIC on day 7. C-GIC exhibited the highest bacterial adhesion, and MDPB-GIC showed the least. The data were analyzed with one-way (ANOVA), and pairwise comparisons were made with Tukey HSD tests.

Conclusion. Hence, it can be concluded that the incorporation of CPP-ACP, BAG, and CH improved the mechanical properties of C-GIC, whereas MDPB improved the resistance of C-GIC to bacterial adhesion.

Evaluation of Degree of Conversion, Resin-Dentin Bond Strength, and Durability of Polydopamine Incorporated Total Etch Adhesive System

Objectives:

This study aimed to evaluate the degree of conversion (DC%), shear bond strength (SBS), bond durability, and the resin-dentin interface of polydopamine (PDA) incorporated total-etch adhesive system.

Materials and Methods:

Five percentage by weight (wt%) concentration of PDA incorporated adhesive was prepared and its polymerization was evaluated using Fourier-transform infrared spectroscopy. The results were compared with the DC% of conventional total-etch adhesive (Adper Single Bond 2) using independent t-test. Occlusal surfaces of 80 freshly extracted human premolars were sectioned to expose the dentin, which was acid-etched. The samples were divided into two groups (n=40) of total-etch adhesive and total-etch adhesive+PDA. Composite resin blocks were built up over the bonded surface and cured. Each group was subdivided into two subgroups (n=20) of immediate and post-aging evaluation. Samples were immersed in 10% sodium hypochlorite for five hours, and then, the SBS was evaluated using a universal testing machine at a crosshead speed of 1 mm/minute. The resin-dentin interface was evaluated using confocal laser scanning microscopy. Data were analyzed using two-way analysis of variance and post-hoc Bonferroni test.

Results:

DC% was not affected by the addition of 5% PDA to the adhesive (group 2). The SBS of group 2A was significantly higher than that of group 1A. There was no significant reduction of SBS in group 2B. The hybrid layer was less degraded after aging in group 2B compared to group 2A.

Conclusion:

PDA incorporated adhesive increased the immediate bond strength and durability without changing the DC%.

Antibacterial evaluation of guava leaves extract and its effect on reactive oxygen species formed by calcium hydroxide and chlorhexidine mixture

Background:

Reactive oxygen species (ROS) are formed when mixing calcium hydroxide (CH) with chlorhexidine (CHX).

Aim:

To analyze the antibacterial efficacy of aqueous (AGL) and ethanolic (EGL) extracts of Psidium guajava leaves against root canal bacteria such as Streptococcus mutans, Staphylococcus aureus, Lactobacillus acidophilus and Enterococcus faecalis, to evaluate the antioxidant potential of the extracts and its ability to counteract the ROS.

Materials and Methods:

Three different concentrations (10%, 25%, and 35%) of AGL and EGL were prepared. The antibacterial efficacy was analyzed using the Kirby-Bauer disc diffusion method. The different concentrations of both AGL and EGL were evaluated for their antioxidant property using ultraviolet spectrometer. Further, the ability of these extracts on neutralizing the ROS formation was analyzed using mass spectrometer.

Results:

CH and CHX mixture exhibited maximum antibacterial activity followed by the same mixture with 35% EGL. EGL showed greater antioxidant activity than AGL extract at all concentrations.

Conclusions:

The addition of natural antioxidants like guava leaves extract decreases ROS formed by CH and CHX mixture.

A novel petasin-modified zinc oxide eugenol sealer

Objective

Zinc oxide eugenol (ZOE) is one of the most commonly used root canal sealer. However, it has few drawbacks such as cytotoxicity, solubility, and irritation to periapical tissues. The scope of this study was to investigate the setting time, solubility, cytotoxic effects, and anti-inflammatory action of ZOE sealer with the modification of its liquid component by the addition of petasin extract in the ratios 1:1, 5:1, and 10:1.

Materials and Methods

Setting time was evaluated using the Vicat's apparatus. For testing solubility, the American Dental Association's specification #8 was adopted with certain modifications. Protein denaturation assay and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assay with L929 mouse fibroblast cell lines were used to evaluate the anti-inflammatory property and cytotoxicity, respectively.

Results

ZOE sealer with petasin extract in the ratio of 5:1 showed the least initial and the final setting times. There was no statistically significant difference in the amount of solubility for all the groups at the various time intervals. The cytotoxicity of the control group was significantly greater than all the experimental groups, whereas the anti-inflammatory effect of the former was statistically lower.

Conclusions

The combination of ZOE with petasin extract in the ratio of 5:1 showed lower setting time, cytotoxicity, and better anti-inflammatory property.

Future Perspectives of Biomimetics in Restorative Dentistry

The main goal of tooth restoration aims at achieving mineralization of initial enamel and dentinal lesions in native form.  Most of the restorative materials and remineralization adjuvants for enamel and dentin mineralization are evidenced in the literature. Although commercially available restorative materials exhibit superior esthetics, mechanical properties and cost effectiveness, durability of the restoration threatened by the occurrence of inadequate strength, long-term solubility, and weaker adhesion to tooth and accelerated degradation after being bonded to tooth structure. Recently, the role of biomimetic science in restorative dentistry aims at creating a restoration that can be highly compatible with the structural, functional and biologic properties of dental tissues to reproduce and emulate the original performance of the intact tooth with high durability. In order to recover the prismatic structure in mineral-depleted enamel and to achieve interfibrillar mineralization in dentin, non-collagenous protein analogues have been proposed as templates for apatite deposition. Biomimetic analogues must be necessary to achieve functional mineralization and to recover the dynamic mechanical properties of teeth. The use of these analogues associated with ion-releasing materials seems to be a promising approach for both enamel and dentin remineralization. This review enlightens the current and future perspectives of biomimetic analogues used for enamel and dentin remineralization as the clinical translation of this biomimetic research can be considered as the boon to restorative dentistry.

Microshear bond strength of composite resin to demineralized dentin after remineralization with sodium fluoride, CPP-ACP and NovaMin containing dentifrices

Background

Bonding composite to remineralized dentin is challenging. The aim of this study was to evaluate the microshear bond strength (μSBS) of composite to demineralized dentin, which had been remineralized with sodium fluoride (NaF), CPP-ACP and NovaMin containing dentifrices.

Materials and methods

108 extracted human premolars or molars were sectioned longitudinally into buccal and lingual halves (n = 216). Dentin (3 × 3 mm) was exposed on the cervical aspect of teeth and the samples were allotted randomly to six groups (n = 36) according to the remineralizing agent used namely, group 1 (sound dentin), group 2 (demineralized dentin), group 3 (NaF), group 4 (CPP-ACP), group 5 (NovaMin) and group 6 (non-fluoridated). The type of bonding system (total-etch or self-etch) formed the subgroups. Samples in groups 2-6 were submitted to an acid challenge for 3 days followed by remineralization in groups 3-6 for 90 days. Etching pattern (n = 3) was observed under SEM. μSBS of the bonded samples (n = 15) were evaluated. The data were statistically analyzed using Kruskal Wallis and Dunn's Post Hoc tests (p < 0.05).

Results

SEM micrographs of remineralized samples showed varying degrees of partially occluded and exposed dentinal tubules. Under both the adhesives, the mean μSBS of composite in groups 2-6 was lesser than that of group 1. Among self-etch subgroups, μSBS of NaF group was not significantly different from that of normal dentin.

Conclusion

Composite forms a weaker bond to remineralized dentin. Self-etch bonding system is capable of achieving acceptable bond strength to dentin remineralized with NaF and NovaMin.

Marginal integrity of aesthetic restorations following intracoronal bleaching with sweet potato extract as an additive: An SEM study

The aim of this in vitro study was to evaluate the marginal integrity of an alkasite restoration in comparison to that of a conventional composite resin restoration following intra-coronal bleaching with 30% hydrogen peroxide (HP) containing sweet potato extract (SPE) as an additive. Access cavities were prepared in 60 extracted human incisors. The teeth were decoronated 2mm below the CEJ and the pulp chambers were sealed cervically. The samples were divided into two groups (n = 30) based on the type of restorative material - group I: Hybrid composite resin and group II: Alkasite restorative material. Both the groups were divided into three subgroups (n = 10) based on the intra-coronal bleaching agent used namely, subgroup A: no bleaching (NB); subgroup B: 30% hydrogen peroxide (HP) and subgroup C: 30% hydrogen peroxide containing SPE (HSP). The tooth-restorative interface was observed under a scanning electron microscope (SEM) to determine the marginal integrity. The results were tabulated and statistically analyzed using one-way ANOVA. Specimens bleached with HP alone showed higher marginal gaps, irrespective of the restorative material used. Subgroups A and C showed lesser marginal gaps under both the restorative materials. An improved marginal integrity was seen with the alkasite material. It can be concluded that the addition of SPE to HP improves the marginal integrity of the coronal restorative material placed immediately post-bleaching. The new alkasite material holds promise as a permanent coronal seal in cases of intra-coronal bleaching.

Comparative Evaluation of Fracture Resistance of Root Dentin Treated with Calendula Officinalis L. and Calcium Hydroxide as Intracanal Medicaments- An In vitro Study

Introduction: Intracanal Medicaments (ICMs) play a major role in disinfection of root canal system. The use of interappointment ICM during endodontic treatment may affect the mechanical properties of dentin which results in decreased fracture resistance of teeth. The use of synthetic medicament is associated with many limitations such as antibiotic overdose, side effects and cytotoxic reactions. In order to overcome this, recent research has been directed towards herbal ICMs with better efficacy and lesser side effects. Aim: To evaluate the effect of a novel herbal ICM Calendula officinalis L. (CO) on fracture resistance of root dentin in comparison to Calcium Hydroxide (CH). Materials and Methods: This in vitro study was conducted in the Department of Conservative Dentistry and Endodontics, SRM Dental College and Hospital, Ramapuram, Chennai, Tamil Nadu. Thirty freshly extracted single rooted human premolar teeth were selected for the in vitro study and randomly assigned into three groups: Group 1: No medication (Control group) (n=10), Group 2: CH (n=10), Group 3: CO (n=10). The samples were decoronated and biomechanical preparation was done followed by placement of respective ICMs in the root canal space, sealed with glass ionomer cement and immersed in saline for a storage period of 7 and 14 days. Each group was subdivided into 5 teeth, depending on the storage period. After each storage period, ICMs were removed and samples were subjected to fracture resistance test using universal testing machine. Data were analysed using One-way Anova followed by Tukey HSD post-hoc test with level of statistical significance set at p<0.05. Results: On evaluation of compressive strength, CO group showed more fracture resistance compared to CH group on 7th day and no statistical significant differences were seen between CO and CH groups on 14th day. Conclusion: CO can be efficiently used as an alternative to CH because of its low toxicity and increased resistance to fracture.

In vitro assessment of interaction between lidocaine hydrochloride and sodium hypochlorite on root canal dentin before and after chemomechanical instrumentation procedures

Introduction

To investigate the effect of resultant precipitate formed on interaction between 2% lidocaine hydrochloride with adrenaline (LA) and 2.5% sodium hypochlorite (NaOCl) on root canal dentin before and after chemomechanical preparation, using scanning electron microscopy (SEM).

Methods

Sixty mandibular premolars were decoronated, and the root length was standardized. All specimens were randomly distributed into the following three groups: Group I (control): 2% LA mixed with sterile water without root canal instrumentation, Group II: 2% LA with 2.5% NaOCl and no instrumentation, and Group III: 2% LA with 2.5% NaOCl, followed by mechanical instrumentation with rotary files. Teeth samples were sectioned into three parts, split and SEM analysis of the root canal wall was done at cervical, middle, and apical root thirds.

Results

SEM images revealed patent dentinal tubules with no precipitate occlusion in the control group, whereas there was occlusion of dentinal tubules with a precipitate in all the specimens in Group II and Group III at all the three root levels studied.

Conclusions

The precipitate formed on the interaction between 2% LA solution and 2.5% NaOCl tends to occlude the dentinal tubules at the coronal, middle, and apical root thirds. The chemomechanical rotary instrumentation procedure did not effectively remove the precipitate from all the three levels of the root specimens studied. LA/sterile water group did not result in any precipitate formation on root canal dentin.

Evaluation of matrix metalloproteinase and cysteine cathepsin activity in dentin hybrid layer by gelatin zymography

AIM

The aim of this study was to comparatively assess the gelatinolytic activity of matrix metalloproteinases(MMPs) and Cysteine Cathepsins (CCs) in the adhesive interface using etch and rinse adhesive at different time intervals using zymographic technique.

METHODOLOGY

Twenty freshly extracted non-carious human third molars were used in this study. Occlusal surfaces were ground flat and 1mm thick horizontal dentin slabs were obtained from each tooth using a diamond disc. The dentin surface was polished with 600-grit silicon-carbide paper. Five out of 20 samples were directly pulverized. In the remaining fifteen samples, the dentin was etched and adhesive was applied and light cured according to the manufacturer's instructions. A 1mm thick flowable composite was build up and light cured. Bonded specimens were cut vertically into 3 to 4 dentin slabs by means of diamond disc to expose the adhesive/dentin interfaces. These were then ground down to 500 µm thick resin-dentin interface using a hard tissue microtome. These sections were then pulverised into powder. Following this, every five samples were subjected to zymographic analysis after 1 day, 7 days and 21 days.

RESULTS

Zymograms showed clear, thicker bands on all three isoforms in the etched samples compared to control samples at 1st and 7th day intervals and became inactive at 21st day for all three isoforms. MMP 9 activity was relatively higher when compared to CCs and MMP 2.

CONCLUSION

Etch and rinse adhesive activated MMPs and CCs within the hybrid layer that remained active till 7th day and no gelatinolytic activity was found on 21st day and MMPs are more active compared to CCs and MMP-2.

Evaluation of polymerization shrinkage, polymerization shrinkage stress, wear resistance, and compressive strength of a silorane-based composite: A finite element analysis study

BACKGROUND

Understanding the mechanical properties is important in predicting the clinical behavior of composites. Finite element analysis (FEA) evaluates properties of materials replicating clinical scenario.

AIM

This study evaluated polymerization shrinkage and stress, wear resistance (WR), and compressive strength (CS) of silorane in comparison with two methacrylate resins.

SETTINGS AND DESIGN

This study design was a numerical study using FEA.

MATERIALS AND METHODS

Three-dimensional (3D) models of maxillary premolar with Class I cavities (2 mm depth, 4 mm length, and 2.5 mm width) created and restored with silorane, nanohybrid, and microhybrid; Groups I, II, and III, respectively. Loads of 200-600 N were applied. Polymerization shrinkage was first determined by displacement produced in the X, Y, and Z planes. Maximum stress distribution due to shrinkage was calculated using AN SYS software. 3D cube models of composite resins were simulated with varying filler particle size. Similar loads were applied. WR and compressive stress were calculated: K W L/H and load/cross-sectional area, respectively. Statistical analysis done using one-way ANOVA, Kruskal-Wallis, and Tukey's honestly significant difference test (P < 0.05).

RESULTS

Polymerization shrinkage (0.99%) and shrinkage stress (233.21 Mpa) of silorane were less compared to microhybrid (2.14% and 472.43 Mpa) and nanohybrid (2.32% and 464.88 Mpa). Silorane (7.92×/1011 μm/mm3) and nanohybrid (7.79×/1011) showed superior WR than microhybrid (1.113×/1017). There was no significant difference in compressive stress among the groups.

CONCLUSION

Silorane exhibited less polymerization shrinkage and shrinkage stress compared to methacrylates. Silorane and nanohybrid showed greater WR compared to microhybrid. CS of all groups was similar.

Maxillary Second Molar with Fused Root and Six Canals- A Case Report

One of the known aberrations in root canal morphology of maxillary second permanent molars is the presence of collateral mesiobuccal canals. This case report describes the endodontic management of a maxillary second molar that had a single fused root with six canals that was successfully managed with the aid of dental operating microscope. Six canal orifices were located namely MB1 (Mesiobuccal), MB2, MB3, DB1 (Distobuccal), DB2 and palatal. During the cleaning and shaping, instrument separation occurred at the apical third of the palatal canal which was removed with ultrasonics. After cleaning and shaping, the canals were obturated with resin sealer and laterally condensed gutta-percha. The patient was recalled for periodic review. After two years of follow up the patient remained asymptomatic. Cone Beam Computed Tomography (CBCT) evaluation revealed satisfactory periapical status.

Dentin remineralizing ability and enhanced antibacterial activity of strontium and hydroxyl ion co-releasing radiopaque hydroxyapatite cement

Dental caries is an infection of the mineralized tooth structures that advances when acid secreted by bacterial action on dietary carbohydrates diffuses and dissolves the tooth mineral leading to demineralization. During treatment, clinicians often remove only the superficial infected tooth structures and retain a part of affected carious dentin to prevent excessive dentin loss and pulp exposure. Calcium hydroxide is used to treat the affected dentin because it is alkaline, induces pulp-dentin remineralization and decreases bacterial infection. Presence of strontium ions has also been reported to exhibit anticariogenic activity, and promote enamel and dentin remineralization. The objective of the present study was to develop novel hydroxyapatite cement from tetracalcium phosphate which gradually releases hydroxyl and strontium ions to exhibit antibacterial activity. Its potential to remineralize the dentin sections collected from extracted human molar tooth was studied in detail. The pH of all the experimental cements exhibited a gradual increase to ~10.5 in 10 days with 10% strontium substituted tetracalcium phosphate cement (10SC) showing the highest pH value which was sustained for 6 weeks. 10SC showed better antibacterial property against S. aureus and E. coli at the end of 1 week compared to other cements studied. It also exhibited the highest radiopacity equivalent to 4.8 mm of Al standard. 10SC treated dentin section showed better remineralization ability and highest elastic modulus. We can conclude that the hydroxyl and strontium ions releasing tetracalcium phosphate cement exhibits good antibacterial property, radiopacity and has the potential to encourage dentin remineralization.

Comparative evaluation of micron- and nano-sized intracanal medicaments on penetration and fracture resistance of root dentin - An in vitro study

Intracanal medicaments play a vital role in disinfection of root canal system. The aim of this study was to evaluate intratubular penetration and fracture resistance of roots filled with micron- and nano-sized intracanal medicaments: calcium hydroxide (CH), nanocalcium hydroxide (NCH), chitosan (CS) and nanochitosan (NCS). Their antibacterial effect on E. faecalis was tested using agar diffusion method. NCH and NCS were prepared by precipitation method and ionic crosslinking respectively. NCH and NCS particles were spherical, with an average particle size of 102±11.3nm and 130±17.6nm respectively. The medicaments were filled in extracted human teeth. Depth of penetration of the medicaments into dentinal tubules at coronal (C), middle (M) and apical (A) thirds was measured. Fracture resistance of the teeth was evaluated after 1 week and 1-month intervals. NCH showed the highest depth of penetration (C ∼746.98μm, M ∼700.30μm, A ∼134.69μm). CS showed the highest fracture resistance, whereas no significant difference was found between other medicaments, at both the time intervals. NCH (8.07±0.06) and NCS (8.13±0.06) showed significantly higher zone of inhibition than CH (7.7±0.17) and CS (7.37±0.15). Under the conditions of this study, it can be concluded that NCH and NCS can be used as potential intracanal medicaments.

Nanochitosan modified glass ionomer cement with enhanced mechanical properties and fluoride release

Conventional glass-ionomer cements (GIC) are one of the most prevalent dental restorative materials, but their use is limited by their relatively low mechanical strength. Efforts have been made to improve the mechanical properties by addition of various fillers of which nano-sized particles appears to be a promising strategy. In the current study, effect of addition of nanochitosan particles in GIC (NCH-GIC) on compressive strength, flexural strength, wear resistance and fluoride release has been evaluated and compared with conventional GIC (C-GIC). Nanochitosan was synthesized by ionic cross linking method and its particle size was found to be 110-235nm. Nanochitosan was mixed with glass ionomer powder at a concentration of 10wt.% and cement samples were prepared. NCH-GIC had significantly higher compressive strength values which could be attributed to early formation of aluminium polysalts. Similarly, flexural strength of NCH-GIC (21.26MPa) was significantly higher than C-GIC (12.67MPa). Wear resistance was also found to increase due to better integrated interface between the glass particle and polymer matrix bonding in NCH-GIC. Fluoride release was significantly higher in NCH-GIC compared to C-GIC for 7 days. It can be anticipated that addition of nanochitosan to GIC will improve the anti-cariogenic and mechanical properties for high strength applications.

A Comparative Evaluation of the Effect of the Addition of Pachymic Acid on the Cytotoxicity of 4 Different Root Canal Sealers-An In Vitro Study

INTRODUCTION

Root canal sealers exhibit varying degrees of cytotoxicity to periapical tissues. This in turn results in inflammation, delayed wound healing, and even bone resorption. This study aimed to explore the effect of the addition of an antioxidant like pachymic acid on the cytotoxicity of 4 root canal sealers, namely, Tubliseal (Kerr, Romulus, MI), a zinc oxide eugenol-based sealer; AH Plus (Dentsply De Trey GmbH, Konstanz, Germany), an epoxy resin-based sealer; Sealapex (Kerr), a calcium hydroxide-based sealer; and EndoREZ (Ultradent Products, South Jordan, UT), a methacrylate resin-based sealer.

METHODS

Sealers mixed according to the manufacturers' instructions formed the experimental groups. Subgroups were determined based on the absence (subgroup A) or addition (subgroup B) of pachymic acid. The experimental sealers were added to L929 mouse fibroblast cells immediately after mixing. Cell viability was evaluated by methylthiazoletetrazolium assay after 24 hours. Data were analyzed using 1-way analysis of variance. Intergroup comparisons were performed using the Kruskal-Wallis test, and intragroup comparisons were done using independent t and post hoc tests.

RESULTS

All 4 sealers were cytotoxic but to varying degrees. In both the subgroups, Sealapex exhibited the lowest cytotoxicity followed by AH Plus, Tubliseal, and EndoREZ (P < .05). The addition of pachymic acid reduced the cytotoxicity of all the sealers except that of EndoREZ (P > .05).

CONCLUSIONS

Calcium hydroxide-based Sealapex showed the least cytotoxicity compared with the other sealers. Pachymic acid could be a viable therapeutic agent to overcome the potential adverse effects associated with root canal sealers.

Microshear bond strength evaluation of surface pretreated zirconia ceramics bonded to dentin

Objectives:

To comparatively assess the micro shear bond strength (MSBS) of dentin bonded surface pre-treated zirconia ceramics.

Materials and Methods:

Zirconia blocks were sectioned into 50 cubical blocks. The blocks were further categorized into five groups (n = 10 each). Group I: No treatment was performed on zirconia samples; Group II: The zirconia samples were sand-blasted; Group III: Group II + etched with 9.8% of hydrofluoric (HF) acid for 60 s; Group IV: The sandblasted zirconia samples were selectively infiltrated with low fusing porcelain; and Group V: Group IV + etched using 9.8% HF acid gel. The zirconia specimens were then bonded to dentin samples, and the samples were tested for MSBS evaluation using universal testing machine.

Results:

The MSBS of all the four experimental groups shows greater value than group I. Among the experimental groups, group V and group IV do not show any statistical significant difference, whereas the mean MSBS of groups IV and V were statistically greater than group III and group II. However, groups I, II, and III do not show any statistical significant difference in mean MSBS values between them.

Conclusion:

Selective infiltration etching of zirconia ceramics provides the highest bond strength with resin cement.