Questionnaire survey on hands-on simulation training using a dental humanoid robot (SIMROID®).

INTRODUCTION: A dental humanoid robot, SIMROID®, is able to replicate the actions characteristic of human beings and enable training for communicating with patients and coping with unexpected situations. This study assessed user experiences via a survey questionnaire following hands-on training on the SIMROID®. MATERIALS AND METHODS: A total of 112 participants, consisting of 50 high school students who visited AUSD (Asahi University School of Dentistry) to participate in open campus events, 42 fourth-year students at AUSD and 20 dental students from Mexico State Autonomy University, University of Siena and Peking University took the survey. The participants observed the movements and reactions of a SIMROID® robot placed on a dental unit for approximately 20 min after which they completed a questionnaire survey. Both Japanese and English versions of the questionnaire were prepared for local and visiting foreign dental students. The questionnaire comprised 8 items, with a further two items for those undertaking dental training and an open comment field. RESULTS: All participants who observed the SIMROID® completed the questionnaire giving a 100% response rate. Generally, simulation training with SIMROID® was highly appreciated by all participants. The comprehensive evaluation score for SIMROID® was 4.56 ± 0.50 points for high school students, 4.05 ± 0.82 points for students at AUSD and 4.70 ± 0.47 points for foreign dental students, showing all participants had a very positive experience and impression of the SIMROID®. CONCLUSIONS: Therefore, simulation training using SIMROID® seems beneficial learning tool.

MDP-salts as an adhesion promoter with MDP-primers and self-adhesive resin cement for zirconia cementation.

PURPOSE: To evaluate the effect of zirconia priming with MDP-Salt before MDP containing primers and self-adhesive cement on the shear bond strength. MATERIALS AND METHODS: Fully sintered high translucent zirconia specimens (n = 120) were assigned into 2 groups (n = 60 each): Control (No Pretreatment) and Methacryloyloxydecyl dihydrogen phosphate salt (MDP-Salt) pretreated. Each group was divided into 3 subgroups (n = 20) according to cementation protocol: 1) MDP + Silane primer and conventional resin cement, 2) MDP+ Bisphenyl dimethacrylate (BPDM) primer and conventional resin cement, and 3) MDP containing self-adhesive resin cement. Shear bond strength (SBS) was measured after 10,000 thermocycling. Contact angle was measured for tested groups. Surface topography was assessed using a 3D confocal laser scanning microscope (CLSM). Weibull analysis was performed for SBS and one-way ANOVA for contact angle and surface topography measurements (α = 0.05). RESULTS: The use of MDP-Salt significantly improved the SBS (p < .05) for all tested subgroups. Self-adhesive cement showed an insignificant difference with MDP + Silane group for both groups (p > .05). MDP + BPDM showed a significantly lower characteristic strength compared to self-adhesive resin cement when both were pretreated with MDP-Salt. No difference between all tested groups in the surface topographic measurements while MDP-Salt showed the highest contact angle. CONCLUSION: MDP-Salt pretreatment can improve bonding performance between zirconia and MDP containing products.

Resin Cement/Enamel Interface: A Morphological Evaluation of the Acid-Base Resistant Zone, Enamel Etching Pattern, and Effect of Thermocycling on the Microshear Bond Strength.

PURPOSE: To evaluate the effects of etching mode (self-etch and etch-and-rinse) on acid-base resistant zone (ABRZ) formation at the resin cement/enamel interface and enamel etching pattern, as well as the effects of thermocycling (0, 5000, and 10,000 cycles) on the enamel microshear bond strength (µSBS) mediated by dual-cure resin cements (DCRC). MATERIALS AND METHODS: Two DCRC were used in 4 groups: Panavia V5 in self-etch (V5NE) and etch-and-rinse mode (V5E); and Estecem II in self-etch (ENE) and etch-and-rinse mode (EE). For ABRZ observation, the bonded interface was subjected to a demineralizing solution. The morphological attributes of the interface and etching patterns were observed using FE-SEM. For µ-SBS, cylinders with a 0.79-mm internal diameter and 0.5-mm height were made with DCRC and tested in shear after 0, 5000, and 10,000 thermal cycles (TC) (5°C and 55°C) (n = 10). RESULTS: The formation of an enamel ABRZ was observed in all groups with different morphological features between self-etch and etch-and-rinse groups. A funnel-shaped erosion beneath the interface was present using V5NE and ENE modes where enamel was dissolved, while ABRZ formation was confirmed and no funnel-shaped erosion was noticed using V5E and EE. No significant differences in µSBS were observed between resin cements. However, significantly lower µSBSs were recorded when the self-etching mode was used. Thermocycling resulted in a significant reduction in µSBS for all groups. CONCLUSION: Selective enamel etching should be recommended to improve the interfacial quality when dual-cure resin luting cements are used.

Analysis of reaction products on hydroxyapatite created by tooth etchants with different compositions.

PURPOSE: The purpose of this study was to investigate the reaction products formed by application of three tooth etchants to hydroxyapatite. METHODS: Tooth etchants with three different compositions, designed for application to teeth before dental adhesive - " K-etchant GEL" (containing phosphoric acid), "Enamel Conditioner" (containing organic acids), and "Multi Etchant" (containing acidic monomer) - were applied to hydroxyapatite plates. RESULTS: Atomic force microscopy measurements revealed that Multi Etchant formed nano-sized particles on the hydroxyapatite. X-ray diffraction and Fourier transform infrared spectrometer analyses of the powdered hydroxyapatite indicated that Enamel Conditioner produced calcium tartrate whereas K-etchant GEL generated monetite. These results indicated that each etchant reacted with hydroxyapatite in a different way. CONCLUSION: Not only differences among the etching ability of etchants, but also differences in the reaction compounds they produce may influence bonding performance in clinical practice.

Influence of different tooth etchants on bur-cut and uncut enamel.

This study aimed to evaluate the effect of pre-etching for two-step self-etch adhesive bonding to bur-cut and uncut enamel. Bur-cut and uncut enamel surfaces were assigned to surface treatments of no etchant (CT), Enamel Conditioner (EC; Shofu, Kyoto, Japan), or K-etchant syringe (KE; Kuraray Noritake Dental, Tokyo, Japan). The bonded samples were thermal cycled and evaluated by microshear bond strength (µSBS). The adhesive interface after acid-base challenge and the conditioned enamel surfaces were morphologically analyzed using scanning electron microscopy (SEM). For bur-cut enamel, EC and KE pre-etching significantly improved µSBS. For uncut enamel, KE showed higher µSBS than EC. SEM observation revealed that only KE removed the prismless layer of the uncut enamel surface. EC could improve enamel bonding and appears to be a substitute for phosphoric acid, especially for bur-cut enamel. However, uncut enamel could not be effectively conditioned by EC with a lower bond strength than KE.

Bacterial adhesion and antibacterial property of coating materials containing theobromine and S-PRG filler.

Theobromine (TB) has been reported to promote tooth remineralization, strengthen tooth substance, and relieve dentin hypersensitivity. This study aimed to evaluate experimental tooth coating materials containing TB and surface pre-reacted glass-ionomer (S-PRG) fillers by examining the effects on bacterial adhesion and antibacterial properties. In addition, the amount of TB eluted from the coating material was measured. There was no significant difference in bacterial adhesion depending on the presence or absence of TB in the coating material, however, a significant decrease in the amount of bacterial adhesion was observed when S-PRG fillers were added to the coating material. The amount of eluted TB did not differ depending on the type of the filler in the coating material. It was suggested that TB could be used to develop a new dental material with the potential ability to inhibit the initiation and progression of dental caries.

Influence of 10-methacryloyloxydecyl dihydrogen phosphate (MDP) incorporated experimental cleaners on the bonding performance of saliva-contaminated zirconia ceramic.

OBJECTIVES: To assess the efficacy of experimental cleaners containing 10-methacryloyloxydecyl dihydrogen phosphate (MDP) on the saliva decontamination of ceramic and their influence in restoring zirconia's adherence to resin cement. MATERIALS AND METHODS: Four hundred sixty alumina-blasted zirconia specimens were categorized into saliva-contaminated and uncontaminated groups which were treated with ceramic primer (P), experimental cleaner 1 (C1), C1 followed by P (C1P), experimental cleaner 2 (C2), and C2 followed by P (C2P). Stainless-steel rods were then attached to the specimens using PanaviaV5 cement (Kuraray Noritake Dental; Tokyo, Japan). Tensile bond strength (TBS) test was performed after 24 h and 5000 thermocycling processes. X-ray photoelectron spectroscopy (XPS) analysis and contact angle measurement of the specimen were performed. The TBS data were analyzed by Weibull analysis and three-way ANOVA. Contact angle data were analyzed by two-way ANOVA (α = 0.05). RESULTS: C2P groups showed the highest TBS in all conditions among tested groups. Saliva contamination led to a significant reduction of TBS in primer- and cleaner-treated groups, with no significant impact on C2P. Adhesive failure was predominant in contaminated groups except with the C1P and C2P groups. XPS revealed that a nitrogen peak was observed on contaminated groups but not in primed groups. The contact angle was significantly affected by saliva contamination, the cleaners, and/or ceramic primer usage (p < 0.001). CONCLUSIONS: The MDP cleaner followed by the MDP primer protocol may overcome the effect of saliva contamination and improve the resin-ceramic bond strength. CLINICAL RELEVANCE: It is recommended to use a combination of MDP-containing cleaner 2 and ceramic primer as a chair-side chemical pretreatment for zirconia substrate with or without saliva contamination.

Color changes in bulk-fill resin composites as a result of visible light-curing.

We evaluated twelve commercially available bulk-fill resin composites to determine the colorimetric changes that occurred as a result of the photo-polymerization reaction. Samples of the resin composites were prepared as disks 8 mm in diameter and 3 mm in thickness. A colorimeter was used to measure the color of samples on a black background before and after the polymerization processed had been initiated. As results, each of the photo-initiated bulk-fill resin composites tested except for Beautifil Bulk A showed a significant color difference more than that of conventional resin composites. Bulk Base Flow became darker, whereas Beautifil Bulk Flow became clearly lighter. All resin composites except for Bulk Base Flow became less yellow. Thus, Beautifil Bulk A exhibited the least color change among all the bulk-fill resin composites. However, this color change showed a marked change (NBS units) as observed by the human naked eye.

Progression of non-carious cervical lesions: 3D morphological analysis.

OBJECTIVES: This longitudinal study aimed to investigate morphologically and quantitatively the progression of non-carious cervical lesions (NCCLs) using a confocal laser scanning microscope (CLSM) and replica models. MATERIALS AND METHODS: The samples examined comprised sets of replicas annually obtained from 83 lesions in 16 participants over 3 to 5 years. All lesions were visually categorized as wedge-shaped, saucer-shaped, or mixed-shaped lesions. CLSM images of the replicas were analyzed in terms of axial depth, occlusogingival width (height) in the buccolingual cross-section, and estimated volume using a custom code of the image analysis software to estimate the progression of the NCCLs over time. The morphological characteristics of the NCCLs were also objectively divided into three groups according to the depth to height ratio (D/H ratio). Fisher's exact test and the Cochran-Armitage trend test were used for statistical analysis. RESULTS: Saucer-shaped lesions progressed mainly in height, whereas wedge-shaped lesions increased both in height and depth. Annual progression in depth and volume significantly increased as the D/H ratio increased. More than half of the NCCLs with a small D/H ratio progressed 50 µm or more in height, whereas none of them progressed more than 50 µm in depth. Annual progression in depth significantly increased as the lesion depth at baseline increased. CONCLUSIONS: Progression patterns significantly differed between NCCLs of different shapes. Most NCCLs progressed slowly in depth regardless of their shape. Moreover, NCCLs may progress through active and inactive stages.

Effect of Air-Particle Abrasion Protocol and Primer on The Topography and Bond Strength of a High-Translucent Zirconia Ceramic.

PURPOSE: To evaluate effect of air-particle abrasion protocol and primer on surface topography and bond strength of resin cement to high-translucent zirconia ceramics. MATERIALS AND METHODS: Two hundred disk-shaped high-translucent zirconia specimens of 5Y-PSZ were prepared. The specimens were assigned to 5 groups in terms of particle type and air-particle abrasion pressure: (1) control, (2) alumina with 0.2 MPa-air pressure [AB-0.2], (3) alumina with 0.4 MPa-air pressure [AB-0.4], (4) glass beads with 0.2 MPa-air pressure [GB-0.2], and (5) glass beads with 0.4 MPa-air pressure [GB-0.4]. Two different primers 1% MDP (Experimental) and MDP-silane primer (Clearfil Ceramic Primer Plus) was also tested. Stainless steel rods were bonded to the 5Y-PSZ specimens with PANAVIA V5. For each group, the tensile bond strength (TBS) was measured after 24-hour water storage (n = 10) and after 5000 thermal-cycling (n = 10) at crosshead speed of 2 mm/min. The data were statistically analyzed using Weibull analysis. Surface roughness (Sa) was measured using a 3D-Laser Scanning Confocal Microscope (n = 5) and analyzed by t-test with Bonferroni correction. Surface topography using scanning electron microscopy (SEM) and surface elemental analysis using energy dispersion spectroscopy (EDX), and cross-section SEM at the interface with composite cement were also investigated. RESULTS: In MDP-silane groups, the highest TBS was observed in AB-0.4 after 24 hours and GB-0.4 after thermal-cycling (p < 0.05). In MDP groups, AB groups resulted in the significantly higher TBS than GB groups (p < 0.05). AB-0.4 group showed the highest Sa value compared to all groups (p < 0.005), meanwhile GB groups did not show different Sa compared to control (p > 0.005). CONCLUSION: Air-abrasion with different particle and blasting pressure can improve bonding to zirconia with proper primer selection. Particularly, glass beads abrasion followed by MDP-silane primer and alumina abrasion followed by MDP primer alone provided stable bond strength of resin cement to high-translucent zirconia after aging. High-translucent zirconia abraded with glass beads achieves a desirable bonding performance without creating surface microcracks which may hinder zirconia's mechanical properties.

The effects of different silicatization and silanization protocols on the bond durability of resin cements to new high-translucent zirconia.

OBJECTIVE: The aim of this study was to assess the influence of different silicatization protocols with various silane treatment methods on the bond performance to high-translucent zirconia. MATERIALS AND METHODS: High-translucent zirconia specimens were assigned to five groups according to mechanical surface pretreatment: as-sintered (Con), 0.2 MPa alumina sandblasting (AB2), tribochemical silica coating (TSC), 0.2 and 0.4 MPa glass bead air abrasion (GB2) and (GB4). Each group was subjected to 4 different cementation protocols: Panavia SA Universal (SAU), Panavia SA plus (SAP), silane + SAP (S-SAP), and Universal adhesive + SAP (U-SAP). Tensile bond strength (TBS) was measured after 24 h and 10,000 thermocycling (TC). Surface topography, surface energy, and elemental composition of the abraded zirconia surface analyses were completed. TBS data was analyzed using the Weibull analysis method. Surface roughness and surface energy were compared by one-way ANOVA analysis of variance (α = 0.05). RESULTS: After 24 h, higher TBS was achieved with all cementation protocols in AB2 and TSC, also, in GB2 with all protocols except U-SAP, and in GB4 with SAU and S-SAP. After aging, GB4/S-SAP, GB2/S-SAP, AB2/U-SAP, and TSC/S-SAP showed the highest bond strength. GB groups showed the lowest surface roughness and highest surface energy. CONCLUSION: Glass bead abrasion achieved the durable bond strength to high-translucent zirconia using a separate silane coupling agent while altered surface chemistry, surface energy, and roughness without effect on morphology. CLINICAL RELEVANCE: Glass bead air abrasion is an alternative to alumina sandblasting and tribochemical silica coating and improves bond strength to high translucent zirconia.

Effects of Immediate and Delayed Cementations for CAD/CAM Resin Block after Alumina Air Abrasion on Adhesion to Newly Developed Resin Cement.

The purpose of this study was to evaluate the effect of one week of Computer-aided design/Computer-aided manufacturing (CAD/CAM) crown storage on the µTBS between resin cement and CAD/CAM resin composite blocks. The micro-tensile bond strength (µTBS) test groups were divided into 4 conditions. There are two types of CAD/CAM resin composite blocks, namely A block and P block (KATANA Avencia Block and KATANA Avencia P Block, Kuraray Noritake Dental, Tokyo, Japan) and two types of resin cements. Additionally, there are two curing methods (light cure and chemical cure) prior to the µTBS test-Immediate: cementation was performed immediately; Delay: cementation was conducted after one week of storage in air under laboratory conditions. The effect of Immediate and Delayed cementations were evaluated by a µTBS test, surface roughness measurements, light intensity measurements, water sorption measurements and Scanning electron microscope/Energy dispersive X-ray spectrometry (SEM/EDS) analysis. From the results of the µTBS test, we found that Delayed cementation showed significantly lower bond strength than that of Immediate cementation for both resin cements and both curing methods using A block. There was no significant difference between the two types of resin cements or two curing methods. Furthermore, water sorption of A block was significantly higher than that of P block. Within the limitations of this study, alumina air abrasion of CAD/CAM resin composite restorations should be performed immediately before bonding at the chairside to minimize the effect of humidity on bonding.

Status of decontamination methods after using dentin adhesion inhibitors on indirect restorations: An integrative review of 19 publications.

The purpose of this review was to assess the literature regarding the decontamination of resin cement before the luting procedure in order to provide clinicians with a comparative overview of decontamination effects. A total of 19 articles were selected for inclusion in this review. The results indicated that bonding effectiveness is reduced due to residual adhesion inhibitors such as saliva, blood, hemostatic agents, and temporary/provisional cement. Self-etching and self-adhesive systems tend to be more negatively affected by adhesion inhibitors than do etch and rinse systems. Cleaning with an ultrasonic scaler or rotating brush have demonstrated conflicting effects in several studies. Some studies have reported that phosphoric acid has negative effects and recommend mild acid for decontamination. The application of phosphoric acid followed by sodium hypochlorite has been shown to help avoid negative effects. Alumina blasting has been investigated as a mechanical cleaning method in a relatively large number of experiments, most of which have confirmed its effectiveness. An intraoral cleaner containing functional monomers that has become commercially available in recent years is a promising method in clinical practice because it can easily and effectively remove temporary adhesive material. In addition, adhesion inhibitors can be easily removed from resin-coated dentin surfaces.

Fluoride-Releasing Self-Etch Adhesives Create Thick ABRZ at the Interface.

A fluoride-releasing adhesive system is expected to promote mineralization of demineralized dentin/enamel around a composite restoration, thereby contributing to the longevity of the restoration. Scanning electron microscopic (SEM) and transmission electron microscopic (TEM) observations revealed the formation of an "acid-base resistant zone" (ABRZ) beneath the hybrid layer when dentin was treated with a self-etch adhesive system. A thicker ABRZ was formed from the upper slope to the end of the outer lesion, indicating greater resistance against an acid-base challenge, when a fluoride-releasing self-etch adhesive system was used. The slope formation of a fluoride-releasing adhesive is believed to be due to fluoride-release from the adhesive. Quantitative assessment of the acid resistance was performed at the interface using the region of interest (ROI) mode of a digital image analysis software package. The area of the ABRZ is influenced by the concentration of fluoride release from the adhesive resin. The threshold of fluoride concentration in the adhesive may exist to influence the morphology of the ABRZ. X-ray absorption fine structure (XAFS) analysis of the dentin treated with different concentrations of NaF-mouth rinses suggested that different fluoride concentrations result in the formation of different chemical compounds, such as fluorapatite and CaF2-like structures, on the dentin surface. This may explain the differences in µTBS values and morphological appearance of the ABRZ. NaF is effective in enhancing the enamel/dentin bond durability and also helps create a high quality of ARBZ to improve the clinical success of restorations.

UV-Mediated Photofunctionalization of Indirect Restorative Materials Enhances Bonding to a Resin-Based Luting Agent.

PURPOSE: The potential of UV-mediated photofunctionalization to enhance the resin-based luting agent bonding performance to aged materials was investigated. METHODS: Sixty samples of each material were prepared. Yttria-stabilized zirconia (YZr) and Pd-Au alloy (Pd-Au) plates were fabricated and sandblasted. Lithium disilicate glass-ceramic (LDS) was CAD-CAM prepared and ground with #800 SiC paper. Half of the specimens were immersed in machine oil for 24 h to simulate the carbon adsorption. Then, all of the specimens (noncarbon- and carbon-adsorbed) were submitted to UV-mediated photofunctionalization with a 15 W UV-LED (265 nm, 300 mA, 7692 µW/cm2) for 0 (control groups), 5, and 15 min and subjected to contact angle (Ɵ) measurement and bonded using a resin cement (Panavia™ V5, Kuraray Noritake, Japan). The tensile bond strength (TBS) test was performed after 24 h. The Ɵ (°) and TBS (MPa) data were statistically analyzed using two-way ANOVA and Bonferroni correction tests (α = 0.05). RESULTS: In the carbon-adsorbed groups, UV-mediated photofunctionalization for 5 min significantly decreased Ɵ of all materials and increased TBS of YZr, and UV for 15 min significantly increased the TBS of LDS and Pd-Au. In noncarbon-adsorbed groups, UV-photofunctionalization did not significantly change the Ɵ or TBS except YZr specimens UV-photofunctionalized for 15 min. CONCLUSION: UV-mediated photofunctionalization might have removed the adsorbed hydrocarbon molecules from the materials' surfaces and enhanced bond strengths of Panavia™ V5 to YZr, LDS, and Pd-Au. Additionally, UV-mediated photofunctionalization improved the overall TBS of YZr. Further investigation on the optimum conditions of UV photofunctionalization on indirect restorative materials should be conducted.

Evaluation of bonding performance and multi-ion release of S-PRG fillercontaining self-adhesive resin composite.

The bonding performance of a surface pre-reacted glass ionomer (S-PRG) filler-containing self-adhesive flowable resin composites to enamel and dentin were evaluated using a tensile bond test with thermal cycling. Also, the quantities of various ions released from the materials were measured using ICP atomic emission spectrometry and a fluoride ion electrode. The initial bond strengths of the materials were approximately 6 MPa, and decreased after thermal cycling. The S-PRG filler-containing self-adhesive flowable resin composites materials exhibited much higher ion release compared with the commercial self-adhesive flowable resin composite possibly due to different acidic monomers contained. It was suggested that the S-PRG filler containing self-adhesive flowable resin composites should be limited as a lining material or to restore small cavities in non-stress bearing areas.

Effects of Different Tooth Conditioners on the Bonding of Universal Self-etching Adhesive to Enamel.

PURPOSE: To investigate the effects of several etching products prior to the application of a one-step self-etch adhesive (1-SEA) or two-step self-etch adhesive (2-SEA) on enamel by microshear bond strength (µSBS) testing and observation of the adhesive-enamel interface. MATERIALS AND METHODS: Ground human enamel surfaces were randomly assigned to one of eight groups according to the combination of surface treatments (either no conditioner [NC], ME [Multi Etchant], EC [Enamel Conditioner], or KE [K-etchant Gel]) and adhesive (ADU [Adhese Universal] or SE2 [Clearfil SE Bond 2]). All groups were further divided into two subgroups: 0 or 10,000 thermal cycles (TC). Then, the µSBS test was performed. The adhesive-enamel interface after acid-base challenge and the surface structure after conditioner application were also observed. RESULTS: With 10,000 TCs, there was no statistically significant difference between ME-ADU and NC-ADU. On the other hand, the µSBS of EC-ADU or KE-ADU was significantly higher than that of NC-ADU, while that of ME-SE2 was significantly lower than NC-SE2. There was no significant difference between EC-SE2, NC-SE2, and KE-SE2. Formation of an acid-base resistance zone (ABRZ) was confirmed in all groups. However, funnel-shaped erosion, which indicates interfacial defects, was observed in the NC-ADU, ME-ADU, and ME-SE2 groups. CONCLUSION: For enamel bonding, application of EC or KE prior to ADU increased the bond strength and created a stable adhesive-enamel interface. On the other hand, SE2 also had stable shear bond strength and interface without the use of conditioners. However, ME decreased the bonding performance of SE2.

The prevalence of non-carious cervical lesions (NCCLs) with or without erosive etiological factors among adults of different ages in Tokyo.

OBJECTIVES: To evaluate the prevalence of non-carious cervical lesions (NCCLs) on teeth with or without erosive etiological factors across a broad range of ages of Japanese adults. MATERIALS AND METHODS: The study sample consisted of a total of 1108 subjects aged 15 to 89 years in Tokyo, Japan. Two examiners evaluated NCCLs and dental erosion (DE) during a full-mouth examination. Subjects were asked to complete a self-administered daily diet, habits, and health condition questionnaire. Subjects who had frequent acid consumption or gastric reflux and at least one tooth with initial enamel wear were placed in the erosion present (EP) group, and the remainder of subjects were placed in the erosion not present (EN) group. Logistic regression analyses were carried out to identify etiological factors of NCCLs associated with DE. RESULTS: Overall prevalence of NCCLs was 60.2%; the prevalence increased with age. There were no statistical differences in the prevalence of NCCLs between the EP and EN groups, except for the 60-69 years group. Multiple logistic regression analysis showed the frequency of consumption of carbonated soft drinks, citrus juice, and acidic fruits such as oranges; tooth brushing pressure; and bruxism were associated with the presence of NCCLs. CONCLUSION: There were no statistical differences in the prevalence of NCCLs with or without erosive etiological factors except for the 60-69 years group. CLINICAL RELEVANCE: NCCL distribution increased with age, and erosive risk factors caused by change in dietary habits might affect the incidence of NCCLs for elders. TRIAL REGISTRATION: UMIN000041982.

The effect of different ceramic surface treatments on the repair bond strength of resin composite to lithium disilicate ceramic.

This study aimed to evaluate the bonding abilities and long-term durability of different repair agents when applied to lithium disilicate ceramics (LDS). Blocks of IPS e.max CAD were prepared and divided into four groups according to the surface treatment: Monobond Etch & Prime (ME), K-etchant GEL+Clearfil Universal Bond (UB), Bondmer Lightless (BL), and K-etchant GEL+G-Multi Primer (GMP). All treated ceramic specimens were bonded to resin composite and light-cured. The micro-shear bond strength was measured after 24 h of water storage or 5,000 thermocycles. ME and BL showed significantly higher initial bond strengths than UB and GMP (p<0.05). After 5,000 thermocycles, there was no significant difference in ME (p>0.05), but BL and GMP showed considerable reduction in bond strength (p<0.05); moreover, the samples of UB were all de-bonded before testing. ME and BL proved to be effective surface treatment materials for LDS.

Influence of primer contamination on the bonding interface of enamel pre-etched with phosphoric acid.

In this study, the influence of primer contamination on enamel bonding was analyzed. Adper Scotchbond Multi-Purpose (SMP), CLEARFIL SE Bond 2 (SE2), Scotchbond Universal (SBU) Adhesive, and Scotchbond Etchant (35% phosphoric acid; PA) were used. Ground bovine enamels were divided into eight groups based on the bonding protocols. The bonding interfaces after an acid-base challenge were observed via scanning electron microscopy to determine the acid-base resistant zone (ABRZ). Moreover, the bonding interfaces after the nanoleakage challenge were analyzed via energy-dispersive X-ray spectroscopy. ABRZ was observed in all the samples except PA_ONLY (applied PA etching, No primer and No adhesive resin). The funnel-shaped erosion was detected only in X_SBU (applied SBU without PA etching). The nanoleakage test revealed silver patterns in some groups. The nanoleakage, i.e., the penetration of the silver ions, was detected in the groups wherein primer was applied on PA-pre-etched enamel.