Composite Resin Cement Research Articles

Progress in the Application of Biomimetic Mineralization for Tooth Repair

The tooth, including enamel and dentin, is a prominent biomineral that is produced by the biomineralization of living organisms. Although the mechanical performance of the tooth is outstanding, caries easily develop in a complex oral environment. The analysis of the chemical composition and the relationship between the mechanical properties and the structure is of great importance in solving caries. In this review, the multilevel structure and mechanical properties of enamel and dentin are briefly introduced, along with caries formation and the limitations of clinical dental restoration. Furthermore, the progress of the application of a wide range of biomimetic strategies for tooth remineralization is highlighted, including the use of calcium phosphate ionic clusters to construct the mineralization front, ensuring the oriented epitaxial growth of enamel crystals and replicating the complex structure of the enamel. Moreover, compared with the current clinical treatment, in which the resin composite and glass ionomer cement are the main repair materials and the high incidence of secondary caries leads to imperfect restorations, the remineralization tactics could achieve excellent repair effectiveness in reconstructing the complicated structure, restoring mechanical strength and gaining permanent repair. A basic understanding of enamel and dentin, their potential for restoration, and hopeful prospects for tooth repair that can be applied in the clinical setting, not just in the laboratory, is provided by this review.

Effect of different surface treatments on the retention force of additively manufactured interim implant-supported crowns.

To compare the effect of different pre-cementation surface treatments and bonding protocols on the retention force of additively manufactured (AM) implant-supported interim crowns. A total of 50 AM interim crowns (Temporary CB resin) were cemented on implant abutments. Five groups (n = 10) were established based on the different surface pre-treatments performed in the intaglio surface of the specimens: no surface pre-treatment (Group C or control), air-abraded with 50-μm aluminium oxide particles (Group AP), air-abraded with 50-μm aluminium oxide particles followed by the application of silane (Group AMP), silane (Group MP), and air-abraded with 30μm silica-coated aluminum oxide particles followed by the application of silane (Group CMP). Each specimen was cemented into an implant abutment using a composite resin cement (Rely X Unicem2). Afterward, the specimens underwent retention testing with a Universal Instron machine. Pull-off forces (N) and modes of failure were registered. Statistical analysis was performed using Mann-Whitney U tests with Bonferroni corrections for multiple tests (α = .05). The median retention force values were 233.27 ±79.28 N for Group Control, 398.59 ±68.59 N for Group MP, 303.21 ±116.80 N for Group AMP, 349.31 ±167.73 N for Group CMP, and 219.85 ± 55.88 N for Group AP. The pull-off forces were significantly greater for Group MP, while the differences between the remaining groups were not statistically significant (P>0.05). Group AP showed the lowest retention force values among all the groups. Failure modes after the pull-off testing were predominantly adhesive and substrate failure of the AM interim material. The surface treatment of the intaglio AM crown tested significantly influenced the retention force values measured. Pre-treatment with an MDP-containing silane improved the retentive force values computed, whereas pre-treatment with 50-μm Al2 O3 air-particle abrasion alone is not recommended prior to cementation on a titanium-based implant abutment. This article is protected by copyright. All rights reserved.

Propriedades estético-químicas e indicações clínicas dos giômeros: revisão de literatura

Giomer is a hybrid restorative material, developed in the 2000s, which presents a combination of characteristics and properties of both composite resin and ionomeric cement, but whose clinical indications are still unclear. The present review aims to evaluate the literature that addresses these indications, as well as the aesthetic and chemical properties, compared to traditional non-hybrid restorative materials. The bibliographic search was carried out in PubMed, LILACS and SciELO databases, from 2016 to 2022. It included articles published in English, Portuguese and Spanish, and used strategies adapted to each database and descriptors compatible with the objective. Publications whose full versions were duplicated and/or unavailable for free access were excluded. From an initial total of 137 articles, 14 were selected. It was observed that there are still doubts about the amount of fluoride released over time and about the possibility of a burst effect, that is, the initial explosion effect that occurs in the first 24 hours and decreases with time, similar to what occurs with glass ionomer cement and not with conventional resins. In the light of the consulted literature, it is possible to conclude that giomers, as well as composite resins, can be widely indicated for restorative procedures, as they have satisfactory resistance and aesthetics, in addition to releasing enough fluoride to prevent caries, making it possible to recharge them from this ion, as in glass ionomer cements.

Evaluation of Fracture Resistance of Endodontically Treated Teeth with Two Different Post System: An In-Vitro Study

Background: The number of endodontic procedures has increased steadily in the past decade with highly predictable results. Therefore, restoration of teeth after endodontic treatment is becoming an integral part of the restorative practice in dentistry. When restoring an endodontically treated tooth, the first step is to assess the level of predictability involved in the restoration. Proper restoration of ET teeth begins with a good understanding of their physical and biomechanical properties, anatomy, and a sound knowledge of the endodontic, periodontal, restorative and occlusal principles. A thorough understanding of posts is necessary to make the right selection, as there are so many choices available. Finally, the choice of core material and the final restoration are important in achieving long-term clinical success. Aim: To compare the fracture resistance of endodontically treated teeth restored with two different post-core systems. Material and Method: The samples were split into two groups of 15 each and given root canal therapy on 30 maxillary incisors. For two experimental groups, post space preparation and tooth restoration utilizing glass fibre posts with composite cores and adhesive resin cement (Group A) and zirconia posts (Group B) respectively were carried out.. Using the universal testing apparatus, 0.5 mm/min of force was applied to each sample at 130 degrees until fracture was experienced. A statistical analysis of the data was done after measuring the fracture resistance. Result: The least fracture resistance was found in Group A (Glass Fibre Post). Additionally statistically more significant than groups A and B was group B (Zirconia Post). According to the statistics that were found, the p value is significant (p< 0.05). Conclusion: The load needed to fracture the custom-made zirconia post was higher than that of the glass fibre post, according to the study's limitations.

Comparative Bonding Analysis of Computer-Aided Design/Computer-Aided Manufacturing Dental Resin Composites with Various Resin Cements

The use of dental resin composites adapted to computer-aided design/computer-aided manufacturing (CAD/CAM) processes for indirect tooth restoration has increased. A key factor for a successful tooth restoration is the bond between the CAD/CAM composite crown and abutment tooth, achieved using resin-based cement. However, the optimal pairing of the resin cement and CAD/CAM composites remains unclear. This study aimed to identify the optimal combination of a CAD/CAM composite and resin cement for bonding. A commercial methyl methacrylate (MMA)-based resin cement (Super-Bond (SB)) and four other composite-based resin cements (PANAVIA V5; PV, Multilink Automix (MA), ResiCem EX (RC), and RelyX Universal Resin Cement (RX)) were tested experimentally. For the CAD/CAM composites, a commercial polymer-infiltrated ceramic network (PICN)-based composite (VITA ENAMIC (VE)) and two dispersed filler (DF)-based composites (SHOFU BLOCK HC (SH) and CERASMART300 (CE)) were used. Each composite block underwent cutting, polishing, and alumina sandblasting. This was followed by characterization using scanning electron microscopy, inorganic content measurement, surface free energy (SFE) analysis, and shear bond strength (SBS) testing. The results demonstrated that the inorganic content and total SFE of the VE composite were the highest among the examined composites. Furthermore, it bonded highly effectively to all the resin cements. This indicated that PICN-based composites exhibit unique bonding features with resin cements. Additionally, the SBS test results indicated that MMA-based resin cement bonds effectively with both DF- and PICN-based composites. The combination of the PICN-based composite and MMA-based resin cement showed the best bonding performance.

Effect of Silver Diamine Fluoride on the Microtensile Bond Strength of Flowable Resin Composite and Glass Ionomer Cement to Carious Primary Dentin (An-In Vitro Study)

Effect of Silver Diamine Fluoride on the Microtensile Bond Strength of Flowable Resin Composite and Glass Ionomer Cement to Carious Primary Dentin (An-In Vitro Study)

The impact of print orientation on the fracture resistance and failure patterns of additively manufactured cobalt-chromium post and cores.

The aim of this study was to evaluate the impact of the print orientation of direct metal laser sintering (DMLS) posts and cores on the fracture resistance and failure patterns of endodontically treated mandibular premolar teeth. Sixty intact human mandibular premolars were endodontically treated. The teeth were then randomly divided into four groups (n = 15). Cobalt-chromium (Co-Cr) metal posts were fabricated by traditional casting (Group C), and DMLS method in 0-, 45-, and 90-degree print orientations (Group DMLS 0, Group DMLS 45, and Group DMLS 90). The posts and cores were cemented with composite resin cement and subjected to compression test at a crosshead speed of 1mm/min. Data was analyzed by using one-way analysis of variance ANOVA and multiple comparison post hoc Tukey tests (α = 0.05). Specimens were viewed under a stereo microscope with x20 magnification to evaluate the fracture types. No significant differences were found among the groups tested in terms of fracture resistance (p>0.05). Group C and Group DMLS 0 group exhibited similar fracture patterns. It is possible to produce post and core restorations with the DMLS technique and use them clinically. Print orientation did not influence the fracture resistance. However, fracture patterns were different. Group C outperformed all DMLS groups in terms of fracture patterns.

Bonding performance of different types of expired and unexpired composite resin cements

Aim: The aim of this study was to compare the bond strength of three expired and unexpired composite resin cements used between tooth and ceramic surfaces. Methodology: In this study, the dentin surfaces of 60 non-carious human teeth and ceramic specimens were bonded with three different resin cements. The resin cements used to bond the teeth and ceramic blocks were divided into two subgroups by expiration date (Group 1a. Variolink II-unexpired, 1b. Variolink II-expired 12 months prior. Group 2a. RelyX Unicem-unexpired, 2b. RelyX Unicem-expired 12 months prior. Group 3a. Panavia F 2.0-unexpired, 3b. Panavia F 2.0-expired 12 months prior). The samples were thermally cycled for 3,000 cycles in a temperature range of 5°C–55°C. The shear bonding test was performed using a universal tester. The force required for ceramic debonding was recorded. Surface fracture analysis was performed using a stereomicroscope. Mann–Whitney U test was used to compare the bond strength of resin cements with different expiration dates. P-value < 0.05 was considered statistically significant. Results: The difference in bond strength between the unexpired resin and the resin that had expired 12 months before the analysis was found not to be statistically significant in the Variolink II and Panavia pairs but significant in the RelyX resin cement pair. Conclusion: The self-adhesive resin cements that expired one year earlier showed lower bond strength than their unexpired counterparts; however, the use of expired total-etch and self-etch systems did not significantly affect bond strength. How to cite this article: Karagözoğlu İ, Aksel L. Bonding performance of different types of expired and unexpired composite resin cements. Int Dent Res 2023;13(2):54-59. https://doi.org/10.5577/idr.2023.vol13.no2.2 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Comparative Evaluation Shear Bond Strength of Resin Composite Cement to Coronal Enamel, Cementoenamel Junction and Root Cementum: An in Vitro Study

Aim: To compare shear bond strength of resin composite cement to coronal enamel, cementoenamel junction and root cementum. Materials and Methods: Twenty one extracted human permanent teeth were selected and randomly divided into three groups(n=21) according to area of adhesion. group 1(n=7): coronal enamel. group 2(n=7): cementoenamel junction. group 3(n=7): root cementum. An area of 5mm x 5mm was selected on tooth of each specified group. Area was etched for 15 seconds with 35% phosphoric acid and washed off. Bonding agent was applied on area and light cured, composite was applied and light cured for 30 seconds. Teeth were mounted in acrylic resin and stored in distilled water. Specimens were subjected to shear load using universal testing machine at cross head speed of 0.5mm/min. Results: According to results obtained from the study comparative shear bond strength (in Mpa) of resin composite cement to coronal enamel, cementoenamel junction and root cementum, highly statistically significant (p<0.001) difference was observed among three groups. Discussion: The cervical area of teeth is most unpredictable region for durable adhesive bonding. This study was performed to evaluate adhesion potential of composite cement to coronal and cervical structures of teeth. Conclusion: Under this study, we can conclude that adhesion to root cementum is less favorable compared to adhesion to CEJ and coronal enamel.

Influence of different surface treatment on bonding of metal and ceramic Orthodontic Brackets to CAD-CAM all ceramic materials

BackgroundDeveloping efficient bonding techniques for orthodontic brackets and all-ceramic materials continues to pose a clinical difficulty. This study aimed to evaluate the shear bond strengths (SBS) of metal and ceramic brackets to various all-ceramic CAD-CAM materials, such as lithium disilicate CAD (LDS-CAD), polymer-infiltrated ceramic (PIC), zirconia-reinforced lithium silicate glass ceramic (ZLS), and 5YTZP zirconia after different surface treatments and thermal cycling.Materials and methodsThe samples were divided into two groups to be bonded with ceramic and metal lower incisor brackets. Each group was subdivided into a control group devoid of any surface treatment, 10% HF acid (HFA) etching, ceramic etch & prime (MEP), Al2O3 air abrasion, and medium grit diamond bur roughening. After surface treatment, brackets were bonded with composite resin cement, thermal cycled, and tested for shear bond strength. The failed surfaces were evaluated with a digital microscope to analyse the type of failure. The data were statistically analysed using a one-way ANOVA and Tukey HSD tests at p < 0.05.ResultsThe highest mean bond strengths were found with HFA etching in LDS-CAD (13.17 ± 0.26 MPa) and ZLS (12.85 0.52 MPa). Diamond bur recorded the lowest mean bond strength roughening across all the ceramic groups. There were significant differences in mean shear bond values per surface treatment (p < 0.001) and ceramic materials.ConclusionAmong the surface treatment protocols evaluated, HFA etching and MEP surface treatment resulted in enhanced bond strength of both ceramic and metal brackets to CAD-CAM all ceramic materials.

Particulate Filler and Discontinuous Fiber Filler Resin Composite's Adaptation and Bonding to Intra-Radicular Dentin.

Seventy virgin human teeth were extracted and then endodontically treated; then samples were randomly divided into 7 groups (n = 10), based on the materials' combinations as follows: Group 1, a two-bottle universal adhesive + DSGFRC; Group 2, a single-component universal adhesive + DSGFRC; Groups 3 and 4, the same materials of Goups 1 and 2 were used but after cleaning of the canal walls with 17% EDTA and final irrigation with 5.25% NaOCl Ultrasound Activated (UA); Group 5, traditional prefabricated fiber posts were luted after being silanized with G-Multi Primer; Groups 6 and 7, like Group 5 but after ultrasonic irrigation (UA). All sample roots were cut 1 mm thick (n = 10) to be evaluated regarding root canal adaptation using a light microscope and scanning electron microscope (SEM) and push-out bond strength. These results were statistically analyzed by Kruskal-Wallis analysis of variance by ranks. The level of significance was set at p < 0.05. Bond strength forces varied between 6.66 and 8.37 MPa and no statistically significant differences were recorded among the groups. By microscopic examination, it was noted that ultrasonic irrigation increased the adaptation of the materials to the dentin surface. Within the limitations of this in vitro study, it may be concluded that when DSGFRC was used for intracanal anchorage in the post-endodontic reconstruction, similar push-out retentive force and strength to those of traditional fiber posts cemented with particulate filler resin composite cements were achieved.

Effects of different treatment modalities on biomechanical behavior of maxillary incisors with external invasive cervical resorption at different progression levels.

This study aimed to evaluate the biomechanical behavior of maxillary incisors with external invasive cervical resorption (EICR) at different progression levels after receiving different modes of treatment under occlusal forces using finite element analysis (FEA). Three-dimensional (3D) models of intact maxillary central incisors were constructed and modified to include EICR cavities with different progression levels in the buccal cervical areas. The EICR cavities confined to dentin were repaired using Biodentine™ (Septodont Ltd., Saint Maur des Fausse ́s, France), resin composite, or glass ionomer cement (GIC) . Additionally, EICR cavities with pulp invasion requiring direct pulp capping were simulated as repaired using Biodentine only or 1 mm thick Biodentine and either resin composite or GIC for the rest of the cavity. Moreover, models with root canal treatment and EICR defects repaired using Biodentine, resin composites, or GIC were also generated. A force of 240 N was applied to the incisal edge. The principal stresses in the dentin were evaluated. GIC showed more favorable results than the other materials in EICR cavities confined to the dentin. However, Biodentine alone resulted in more favorable minimum principal stresses (Pmin ) compared to other materials in EICR cavities with close pulp proximity. Exceptionally, the models localized in the coronal third of the root with a circumferential extension of the cavity >90° showed more favorable results for GIC. The presence of root canal treatment had no significant effect on stress values. Based on this FEA study the use of GIC in EICR lesions confined to the dentin is recommended. However, Biodentine may be a better option for restoring EICR lesions close to the pulp with or without root canal treatment. Except when the circumferential extension of the cavity is >90°, the use of GIC may be more advantageous.

The effect of different strong acids and silica‐coating on resin Ti adhesion

The presence of Si on the Ti surface is quintessential for a strong, durable silane‐based adhesion utilized in several dental applications. Silica‐coating and silanization form durable ≡Si‐O‐Si≡ bonds, which might have a positive effect on resin‐Ti adhesion. This laboratory study studied the effect of strong acids, their blends, and silica‐coating on Ti and resin‐Ti bonding. One‐hundred sixty‐eight c.p. grade 2 polished Ti samples (10 mm × 10 mm × 1 mm), out of which 96 were etched with 9% and 12%HF, a blend of 35%HCl+85%H3PO4 and a blend of 69%HNO3+35%HCl at 60°C, each for 2 min. One half was silica‐coated (Rocatec™ Plus, 110 μm SiO2‐coated‐Al2O3). Sixty Ti samples were first silica‐coated, and then, 48 of them were etched with 9%HF, 12%HF, a blend of 35%HCl+85%H3PO4, and a blend of 69%HNO3+35%HCl at 60°C for 2 min. SEM, EDX, XPS, and Ra analyses were carried out. Polished Ti samples were controls. All silanizations were carried out with a blend of 0.3 vol% 1,2‐bis‐(triethoxysilyl)ethane+1.0 vol% 3‐acryloxypropyltrimethoxysilane. Multilink™ Automix self‐adhesive resin composite cement was used in adhesion testing, and the samples were artificially aged followed by enclosed‐mold micro‐shear test on day 1 and weeks 1, 4, and 8. Failure mode analysis and statistical analysis with one‐way/two‐way ANOVA (p &lt; 0.05) were carried out. HF etching produced the highest surface roughness. XPS analysis identified after etching with HF a variety of Ti and Si ions: Ti4+, Ti3+, Ti2+, and Ti0 and, on the other hand, Si4+, Si3+, and Si2+. A gradual decrease in adhesion strength was observed after artificial aging. Adhesive and cohesive failures were observed.

Analysis of Shear Bond Strength and the Quality of the Interface Between Composite Resin and Novel Hybrid Calcium Silicate Cements

Hybrid calcium silicate cements (HCSC) are new bioactive materials of the fourth generation with the main application as pulp capping agents and/or as liners in indirect pulp capping. The aim is to analyze the shear bond strength and the quality of the interface between a composite restorative material and a new bioactive material and other hybrid cements at the same conditions. The used pulp-capping hybrid materials: TheraCal and the new hybrid biomaterial BioCal-Cap. In this study only one type of adhesive system (Scotchbond 3M, St. Paul, MN, US) and resin-based composites (Filtek Ultimate 3M, USA) were used. For this purpose, 60 molds were prepared and divided into 4 groups. Half of them were filled with TheraCal and the other 30 with BioCal-Cap. The shear bond strength between calcium-silicate cements and the composite material was investigated. Mann-Whitney test and Wilcoxon Signed Ranks Test were used for statistical analysis of the results. In both of the materials there was no statistically significant difference in the results after the immediate and postponed placement of the composite material. Nevertheless, in both of them there was a tendency for a slight increase in shear strength in the samples which delayed the application of the restorative material. The novel hybrid material BioCal-Cap was reported to have higher shear strength values (18.06 – 20.25 MPa) at both time periods in comparison to the values for TheraCal (13.71 – 15.58 MPa). The data clearly showed that the time of the composite material placement did not affect the shear bond strength in each of the observed groups. The median value was shifted higher after the immediate composite placement, which supported one-step treatment approach to the novel hybrid material BioCal-Cap, while the TheraCal LC exhibited the opposite tendency. The adhesive layers in both hybrid cements were homogeneous, properly structured, without the presence of microcracks and gaps, and had different thicknesses at different recovery times.

A COMPARATIVE EVALUATION OF ENAMEL SURFACE ROUGHNESS OF TWO DIFFERENT BONDING ADHESIVES AFTER DEBONDING WITH ATOMIC FORCE MICROSCOPY

Introduction: The goal of this research was to evaluate the pain felt by patients after veneers were debonded and gum remnants were removed using a tungsten carbide (TC) brush from two different cement frameworks: light fix composite and glass ionomer concrete glues. So long as we assume the null hypothesis is true, the two adhesive solutions do not vary in their ability to smooth out imperfections on the enamel surface.&#x0D; Materials and methods :- Based on the consideration and prohibition models, this in vitro study examined sixty newly removed human premolar teeth (n = 60) to assess orthodontic plans. Light fix cement (Trans bond XT, 3M Unitek, Monrovia, CA) was used to strengthen the metal portions in Group I (n = 30), whereas light glass ionomer concrete (GC Fuji Ortho LC, Tokyo, Japan) was used to accomplish the same in Group II (n = 30). The dried residues of the concrete glue were removed using a TC brush and a slow-speed handpiece. Maximum roughness (Rmax), root mean square roughness (Rq), and roughness (Ra) were all determined at time zero (before holding). and their attributes were compared to those at time two (after debonding and completion).&#x0D; Results:-The two groups had very different experiences with the roughness of the polished surface when held. The composite resin and glass ionomer cement groups had statistically significant (p0.001) differences in surface roughness.&#x0D; Conclusion:- After debonding the sections and finishing with a TC brush, the surface roughness of the veneer significantly increased with both the light fix and the glass ionomer strong concrete structures. The enamel surface roughness of the light cure group was worse than that of the glass ionomer cement group.

In Vitro Evaluation of the Bond Strength of Metal Brackets Adhered to Different Dental Restorative Materials using Different Orthodontic Adhesives

ABSTRACT Background: During orthodontic treatment, teeth with brackets may sometimes be restored with different restorative materials. In this case, the content of the orthodontic adhesive selected for bracket bonding may also be important. Aim: This study compared the bond strength of metal orthodontic brackets adhered to different resin composite and glass ionomer cement (GIC) restoration surfaces with glass ionomer-based and resin-based orthodontic adhesives to determine the best orthodontic adhesive for use in restored teeth. Material and Methods: This study prepared 80 discs. Four material groups of 20 discs were created: reinforced high-viscosity GIC, high-viscosity GIC, flowable bulk-fill resin composite, and nanohybrid resin composite. Specimens in each material group were divided into two subgroups that differed in the orthodontic adhesive used to bond the brackets to the prepared specimens. After 24 hours, the specimens were shear bond strength (SBS) tested at 1 mm/min using a universal tester. Results: The SBS of glass ionomer-based orthodontic adhesive differed significantly between metal brackets adhered to different bases (P &lt; 0.001). The highest SBSs were observed between metal brackets and high-viscosity glass ionomer restorations (6.79 ± 2.38). The highest SBSs observed with a resin-based orthodontic adhesive were between metal brackets adhered to nanohybrid resin composite restorations (8.84 ± 2.10; P = 0.030). Conclusions: Glass ionomer-based orthodontic adhesive provided safer bond strength and demineralization prevention when applying metal brackets to teeth with glass ionomer restorations.

Resin composite cements: Current status and a novel classification proposal.

Currently, a classification of resin cements that includes relatively recently formulated ("universal") cements is lacking. Furthermore, the terminology used to define different resin cements in the scientific reports is inconsistent. Accordingly, this work aims to: (i) propose a novel classification of resin composite cements; (ii) disambiguate the term "universal cements" and (iii) present an overview of the properties of these cements. An analysis of peer-reviewed literature (PubMed search), as well as market research on definitive resin composite cements were performed. A tendency toward simplified and versatile luting materials was observed both in the scientific literature and on the dental market with the advent of self-adhesive/one-step resin cements. However, additional priming procedures were necessary to improve their bonding performance in certain clinical situations. Hence, several cements that can be applied both in adhesive and self-adhesive mode were introduced. These cements are associated with a universal adhesive resin, that can be used as a tooth and/or restorative material primer, without the need for other priming systems, regardless of the substrate. These systems should be considered truly universal. Therefore, we hereby suggested a new classification of resin-based cements: (1) adhesive/multi-step; (2) self-adhesive/one-step; (3) universal cements (one- or multi-step). Despite promising in vitro results, clinical trials and long-track laboratory studies are necessary to confirm the reliability of the universal cements. This review presented the current advances in the field of resin-based cements, which are reflected in the proposed classification. The term "universal cement" was disambiguated, which will help standardize the terminology used in published research. The classification of resin-based cements and a better understanding of the proper terminology will help standardize the terminology in published research, as well as improve the understanding of the clinical practitioners of the different indications and possible modalities of use of the available cements.

Comparison of surface roughness of additively manufactured implant-supported interim crowns fabricated with different print orientations.

To assess the influence of print orientation on the surface roughness of implant-supported interim crowns manufactured by using digital light processing (DLP) 3D printing procedures. An implant-supported maxillary right premolar full-contour crown was obtained. The interim restoration design was used to fabricate 30 specimens with 3 print orientations (0, 45, and 90 degrees) using an interim resin material (GC Temp PRINT) and a DLP printer (Asiga MAX UV) (n=10). The specimens were manufactured, and each was cemented to an implant abutment with autopolymerizing composite resin cement (Multilink Hybrid Abutment). Surface roughness was assessed on the buccal surface of the premolar specimen by using an optical measurement system (InfiniteFocusG5 plus). The data were analyzed with a Shapiro-Wilk test, resulting in a normal distribution. One-way ANOVA and the Tukey HSD tests were selected (α=0.05). Statistically significant discrepancies were found in the surface roughness mean values among the groups tested (p<0.001). The lowest mean±standard deviation surface roughness was found with the 90-degree group (1.2±0.36μm), followed by the 0-degree orientation (2.23±0.18μm) and the 45-degree group (3.18±0.31μm). Print orientation parameter significantly impacted the surface roughness of the implant-supported interim crowns manufactured by using the additive procedures tested.

Impact Of Restorative Material On Fracture Strength Of Root Canal Treated Teeth: An In Vitro Study.

There are several materials available in the market for the core buildup of endodontically treated teeth. The purpose of our study is to evaluate the fracture resistance of endodontically treated teeth restored with composite resin, amalgam and glass ionomer cement as core buildup materials. Forty-eight sound-extracted mandibular premolar teeth were randomly divided into 4 groups of 12 teeth each. The first group served as a control and consisted of intact sound teeth. In all of the remaining teeth, root canal treatment was performed first. In Group II composite resin was used as the core build-up material Group III amalgam and Group IV GIC. Teeth were then subjected to fracture using a universal testing machine. One Way ANOVA test was performed to study the differences in the data of the four groups. The mean forces required for fracture were 1050 N for control teeth, 738 N for composite, 872 N for amalgam and 567 N for GIC. The variation is of statistical significance as depicted by a p-value of 0.003. The highest strength was shown by intact sound teeth. Teeth restored with composite resin and amalgam had similar strengths and those with GIC had significantly lower resistance to fracture.

Mechanical Stability of Self-Adhesive/Ion-Releasing Resin Composites

The purpose of this study was to assess the effects of water storage on the surface microhardness (VHN) and fracture toughness (K1C) of two self-adhesive restorative materials compared to traditional resin composite and resin-modified glass ionomer cement (RMGIC) restorative materials. Methods: Two self-adhesive materials (Activa and Vertise Flow), a nonflowable composite (Filtek Z250), and an RMGIC (Fuji II) were evaluated. Hardness measurements (n = 12) were recorded at three time intervals: (i) one-hour post-irradiation; (ii) after one day of storage in water at 37 °C; and (iii) after 90 days of storage in water at 37 °C. Fracture toughness (K1C) measurements (n = 12) were conducted after one day of storage in water at 37 °C and 90 days of storage in water at 37 °C. ANOVA and Tukey post hoc tests were used for statistical analysis. Results: Baseline VHN data were 38.2–58.3, decreasing significantly to 28.8–55.6 following 90 days of water storage. The Filtek Z250 had the highest VHN before and after storage, while the Activa had the lowest. KIC values varied between 0.98–1.32 MPa·m0.5. The highest value was for the Filtek Z250 while the Fuji II showed the lowest value (after both 1 and 90 days of storage in water). However, KIC values decreased significantly after storage, except for the Fuji II. Conclusion: Self-adhesive/ion-releasing resin composites were negatively affected by water storage. Material reinforcements are possible future areas to explore.