Adhesive Restorations Research Articles

Quantitative Evaluation of Enamel Thickness in Maxillary Central Incisors in Different Age Groups Utilizing Cone Beam Computed Tomography a Retrospective Analysis

Background/Objectives: The presence of enamel on the tooth surface is crucial for the long-term success of minimally invasive adhesive restorations such as dental veneers. Our study aims to evaluate the enamel thickness in the incisal, middle, and cervical portions of the labial surface of the upper central incisors using cone beam computed tomography (CBCT). This imaging method provides detailed and accurate three-dimensional images with a low radiation dose, allowing an accurate assessment of enamel thickness. The analysis aims to identify variations in enamel thickness depending on the age and different levels of the labial tooth surface. Methods: 800 CBCT scans performed for diagnostic or therapeutic purposes on patients aged 18–60 years were analyzed. The data were gathered from the imaging archives of private practitioners from Targu Mures and the “George Emil Palade” University of Medicine, Pharmacy, Science, and Technology of Targu Mures. Enamel thickness measurements were conducted using the OnDemand3D Communicator CBCT evaluation program, with subsequent statistical analysis performed using GraphPad Instat Prism software. Results: Results showed significant variation in enamel thickness between the incisal, middle, and cervical segments of the labial surface of the upper central incisors. A decrease in enamel thickness with age has been observed. In patients aged 18–40, mean values of enamel thickness 1 mm and 3 mm above the cementoenamel junction (CEJ) were 0.48 ± 0.092, respectively, 0.819 ± 0.158. In patients over 40, the mean values were 0.454 ± 0.116 and 0.751 ± 0.067 at 1 mm, respectively, 3 mm above the CEJ. Statistically significant differences were found between the two age groups at 1 mm and 3 mm above the CEJ, with p < 0.0001 and p = 0.0214. Conclusions: A statistically significant decrease can be observed in enamel thickness in almost the entire labial surface of the upper central incisors with aging. The varied thickness of the enamel at different tooth levels requires individualized planning for each patient to maximize the long-term aesthetic and functional results.

Adhesive restorations in primary dentition: A retrospective analysis of survival rate and associated factors.

Several clinical and individual factors may play a role in the survival rate of dental restorations, such as characteristics related to the child's age and oral hygiene, and factors associated with the tooth, such as the type of material and number of surfaces to be restored. To analyse the survival rate of adhesive restorations on primary teeth and factors associated with restoration survival. The study included dental records of children aged 3-12 years having received adhesive restorations on primary teeth at a Brazilian dental school between 2009 and 2019. A Kaplan-Meier survival curve was used to plot survival rates using the log-rank test. A multivariate Cox regression model was run to identify individual and dental factors associated with restoration failure. The sample comprised 269 restored teeth in 111 children. Survival curves were similar for all materials (p = .20) and types of isolation (p = .05). The annual failure rate was 3.60% for glass ionomer cement, 1.23% for resin-modified glass ionomer cement and 0.40% for composite resin. The following variables were associated with more failures: Class II restoration compared with Class I (HR = 1.96; 95%CI: 1.28-2.99, p < .001), proportion of decayed teeth (HR = 11.89; 95%CI: 2.80-50.57, p < .001) and child's age (HR = 1.17; 95%CI: 1.06-1.29, p < .001). The different materials and types of isolation had similar survival rates. Children with more decayed teeth have an increased risk of restoration failure.

Digital Approach Provides Predictability in Increasing the VDO in Erosive Wear: Clinical Technique and 9-Year Follow-Up.

This clinical case describes a digital workflow using face scans and CAD/CAM technology for a full-mouth rehabilitation with increased vertical dimension of occlusion (VDO) with adhesive lithium disilicate restorations after 9 years. A healthy, 46-year-old man displaying severe tooth wear, underwent an extensive full-mouth rehabilitation involving an increase of the VDO through laminate veneers and adhesive partial coverage lithium disilicate restorations. Anatomical landmarks of the face and reference planes were captured using a digital face scanning system. The anatomical position of the maxilla was registered with a transfer device. Digital data sets of the intraoral situation combined with a facial scan enabled precise virtual planning, guiding minimally invasive preparations. Long-term provisional restorations, milled from high-performance polycarbonate, were used to test the novel VDO before the final lithium disilicate restorations were fabricated. This approach provided a time- and cost-efficient treatment solution. No failures were observed at the 9-year follow-up. Utilizing face scans and design software enable a virtual visualization and comprehensive quality control for patients with dental wear, resulting in significant time savings and increased predictability for the dental technician, dentist and patient. The described digital workflow optimizes the planning and implementation of a comprehensive adhesive full-arch rehabilitation with an increase of the VDO. The clinical long-term follow up result of CAD/CAM assisted minimally invasive lithium disilicate restorations after 9 years demonstrates to clinicians a reliable treatment concept for patients with dental wear.

Research on the method of digital technology assisted direct resin composite restoration for deep distal caries in mandibular second molars

Objective: To explore the digital design and fabrication technology of personalized restorative matrix for dental filling, and to explore the feasibility of direct resin restoration for deep caries lesions in distal neck of mandibular second molar. Methods: For patients with deep caries lesions in the distal neck of the mandibular second molar who visited the Department of Cariology and Endodontology of Peking University School and Hospital of Stomatology from September 2023 to April 2024, after preparing the cavity and gingival retractor, a three-dimensional intraoral scanner was used to obtain three-dimensional data of the patient's dentition. In the dental restoration computer-aided design software, the inlay function was used to generate the restored tooth morphology. The edge range of the personalized restorative matrix was drawn on the restored model by three-dimensional reverse engineering software to achieve edge sealing effect. The selected edge range data was processed with distal shelling to generate a digital model of a personalized restorative matrix with a thickness of 0.5 mm. A metal three-dimensional printer was used to fabricate the titanium alloy restorative matrix, and its application was completed in 10 clinical cases. The marginal adaptation and retention stability of the personalized restorative matrix were evaluated under a dental microscope, and forming effect evaluation was performed through immediate postoperative periapical radiographs. Results: The preliminary clinical application of the personalized restorative matrix fabricated using digital technology revealed that, in the treatment of 10 affected teeth, rubber dam isolation was successfully ensured, resulting in clinically effective direct resin composite restorations with optimal marginal adaptation and reasonable contours. Immediate postoperative periapical radiographs showed good convexity of the filling body, with no overhangs found. Both marginal adaptation and retention stability met the requirements of clinical treatment. Conclusions: The personalized restorative matrix designed in this study can solve the clinical problems of moisture separation and resin forming in the treatment of deep caries lesions in distal neck of the mandibular second molar, and can achieve stable and reliable adhesive restoration effects.

EVOLUTION OF DENTIN ADHESIVES: LITERATURE REVIEW

The aesthetic demand has culminated in the improvement of restorative dentistry through new products, such as dentin adhesives, so commonly used in current restorative procedures. The quality of the bond between the restorative material and the dental substrate is essential for the longevity of the treatment; therefore, dentin adhesives with different compositions are commercialized, aiming to achieve ideal adhesion. The present study aimed to review the literature on the evolution of dentin adhesives, since research can bring to light innovations that overcome the limitations of contemporary adhesive systems. This article shows the evolution of dentin adhesive agents, their effectiveness and clinical relevance. Knowing new dentin adhesives, techniques and necessary care before and during the application of the chosen adhesive contributes to increasing the durability of adhesive restorations, in order to ensure satisfactory results in the bond between the resin and the dental substrate, avoiding the repetitive restorative cycle.

Marginal Degradation of Universal Adhesive Restorations in NCCLs: A Systematic Review and Meta-analysis

Purpose This systematic review aimed to answer the PICO question: do adhesive protocols used for non-carious cervical lesions (NCCLs) using a universal adhesive system influence marginal degradation, marginal staining, and retention of these restorations? The self-etching adhesive strategy and selective enamel etching were compared with the etch-and-rinse strategy as a control. Materials and Methods The study searched various databases, including PubMed, Web of Science, Cochrane Central Register of Controlled Trials, Scopus, Embase, and grey literature, to find randomized clinical trials (RCTs) comparing self-etching (SE) or selective enamel etching (SEE) to the etch and rinse (ER) strategy. The risk of methodological bias was assessed using the Cochrane RoB 2 tool. Data were dichotomized and analyzed using RevMan v 5.3, adopting the Mantel-Haenszel method. The quality of evidence was assessed using Grading of Recommendations Assessment, Development and Evaluation (GRADE). Results Twenty RCTs were included in the meta-analysis. Results showed that using universal adhesives with the SE strategy resulted in clinical signs of marginal degradation at 12 months, 24 months, and 36 months of follow-up, and marginal staining at 24 months. The adhesive strategy did not interfere with the retention of restorative material used for NCCLs over 36 months, as assessed based on both the United States Public Health Service (USPHS) and World Dental Federation (FDI) criteria. Conclusion With moderate certainty of evidence, after 24 months of follow-up, the SE strategy results in the detection of clinical signs of marginal degradation and staining. The adhesive strategy adopted did not influence the retention rate of the restorations over 36 months of follow-up.

Constructing the Enamel-Like Dentin Adhesion Interface to Achieve Durable Resin-Dentin Adhesion.

Enamel adhesion is acknowledged as durable; however, achieving long-lasting dentin adhesion remains a formidable challenge due to degradation of exposed collagen matrix after acid-etching of dentin. The idea of developing an enamel-like adhesion interface holds great promise in achieving enduring dentin adhesion. In this study, we constructed an enamel-like adhesion interface using a rapid remineralization strategy comprising an acidic primer and a rapid remineralization medium. Specifically, the acidic primer of 10-methacryloyloxydecyl dihydrogen phosphate (MDP) and epigallocatechin-3-gallate (EGCG) nanocomplex (MDP@EGCG primer) was utilized to partially demineralize dentin within 30 s, and the MDP@EGCG nanocomplex showed a strong interaction with exposed collagen, enhancing collagen remineralization properties. Then, the rapid remineralization medium containing polyaspartate (Pasp) stabilized amorphous calcium and phosphorus nanoclusters (rapid Pasp-CaP) was applied to modified dentin collagen for 1 min, which caused rapid collagen remineralization within a clinically acceptable time frame. This strategy successfully generated an inorganic rough and porous adhesive interface resembling etched enamel, fundamentally addressed issues of collagen exposure, and achieved durable dentin adhesion in vitro and in vivo while also ensuring user-friendliness. It exhibited potential in prolonging the lifespan of adhesive restorations in clinical settings. In addition, it holds significant promise in the fields of caries and dentin sensitivity treatment and collagen-based tissue engineering scaffolds.

Importance of an Evaluation Phase When Increasing the Occlusal Vertical Dimension: A Systematic Review.

To assess whether an evaluation period is necessary for patient and clinical success when increasing the occlusal vertical dimension (OVD) for a full mouth rehabilitation. A systematic search was conducted in six databases: MEDLINE, Web of Science, Scopus, CENTRAL, VHL, and EMBASE. The eligibility criteria of this systematic review used the PICO framework to address the following research question: "In dentate adults requiring an increase in occlusal vertical dimension (OVD) (P), is an evaluation period of the new OVD (I) superior to no evaluation period (C) in terms of success (O)?" Study characteristics, survival, and success rates were extracted from each article. No language restrictions were applied. Study quality was appraised using Cochrane's Risk of Bias 2 tool and Newcastle-Ottawa Scale (NOS) according to the study design. The electronic search yielded 1188 titles after duplicates were removed. One RCT and 103 non-comparative articles were found relevant to the search question. Out of the 103 articles, 80 had an evaluation phase and 23 did not. The included RCT revealed that removable devices tended to cause chewing difficulties, unclear speech, and esthetic discomfort. Therefore, the use of a removable appliance to functionally or esthetically evaluate OVD was not indicated prior to the definitive treatment. Esthetics was the highest reported parameter preoperatively for the non-comparative studies, at 85% with an evaluation and 86% without. At present, there is lack of evidence that an evaluation period improves clinical and patient-reported outcomes when increasing OVD for full mouth rehabilitations. Thus, an increase in OVD can be successful with or without an evaluation phase. The evaluation phase helps the clinician manage patient expectations and assist with the treatment sequencing. This phase is most effective with fixed restoration, such as temporary crowns or adhesive restorations. However, there is limited evidence that this phase improves clinical or patient-reported outcomes.

Effect of double adhesive layer application on micro-tensile dentin bond strength of a universal adhesive

IntroductionAchieving optimal dentin bond strength is crucial for the long-term success of adhesive restorations. This study aims to evaluate the impact of double adhesive layer application, with and without light curing between applications, on the micro-tensile dentin bond strength (µ-TBS) of a universal adhesive, in comparison to the conventional single-layer application.MethodsIntact human molars were divided into three groups (n = 15) according to the adhesive application technique using a universal self-etch adhesive (Tetric N-Bond Universal, Ivoclar) as follows: (1) according to the manufacturer's instructions, (2) double-layer application without light curing between layers, and (3) double-layer application with light curing between layers. Samples were immediately tested for µ-TBS, with failure types recorded as adhesive, cohesive, or mixed. Representative samples were observed by scanning electron microscopy. Data were analyzed using multiple-way ANOVA (α = 0.05).ResultsThe double adhesive layer with and without light curing between layers showed similar μ-TBS to that of the control group (p &amp;gt; 0.05).DiscussionFrom a clinical perspective, these findings suggest that the accurate application of a single layer of a universal adhesive can be as effective as more complex techniques. Additionally, the use of universal bonding agents may have contributed to the outcomes observed in this study. In conclusion, double adhesive layer application and light curing between adhesive layers did not increase the µ-TBS with the universal adhesive agent explored.

Effect of different preparation designs and material types on fracture resistance of minimally invasive posterior indirect adhesive restorations.

To evaluate the impact of various preparation designs and the material type on fracture resistance of minimally invasive posterior indirect adhesive restorations after aging using a digital standardization method. One-hundred sixty human maxillary premolars free from caries were assigned into 16groups (n=10): bevel design on enamel substrate with mesial box only (VEM), butt joint design on enamel substrate with mesial box only (BEM), bevel design on enamel substrate with mesial and distal box (VED), butt joint design on enamel substrate with mesial and distal box (BED), bevel design on dentin substrate with mesial box only (VDM), butt joint design on dentin substrate with mesial box only (BDM), bevel design on dentin substrate with mesial and distal box (VDD), and butt joint design on dentin substrate with mesial and distal box (BDD). Each group was restored with pressable lithium disilicate (LS2) or disperse-filled polymer composite (DPC) materials. Adhesive resin cement was used to bond the restorations. The specimens were aged for 10,000 thermal cycles (5°C and 55°C), then 240,000 chewing cycles. Each specimen was subjected to compressive axial load until failure. A two-way analysis of variance (ANOVA) test followed by a post hoc Tukey test was used to analyze the data (α=0.05). The two-way ANOVA test revealed a significant difference among designs (p<0.001) and materials (p<0.001) with no interaction effect (p=0.07) between the variables. The Post hoc Tukey test revealed that the VEM group exhibited the highest mean fracture resistance value, while the BDM group had the lowest. The LS2 groups showed the highest mean fracture resistance values. The DPC groups showed a restorable fracture pattern compared to the LS2 groups. Bevel and butt joint designs with mesial or distal boxes are recommended for conservative posterior indirect adhesive restorations in premolar areas. Enamel substrate improved load distribution and fracture resistance. DPCs have restorable failure patterns, while pressed LS2 may harm underlying structures.

Titanium oxide and chitosan nanoparticles loaded in methylene blue activated by photodynamic therapy on caries affected dentin disinfection, bond strength, and smear layer removal efficacy

AimEffect of nanoparticles (NPs) loaded methylene blue (MB) mediated photodynamic therapy (PDT) on caries-affected dentin (CAD) against S.mutans, smear layer (SL) elimination, and shear bond strength (SBS) of single bottle 7th generation adhesive. MethodologySixty human molars with carious lesions were selected. Samples were randomly allocated into four groups, based on the disinfection regime (n = 11) Group 1-(CHX), Group 2-(MB-PDT), Group 3-(MB-CNPs-PDT), and Group 4-(MB-TiO2NPs-PDT). Following disinfection S.mutans' survival rate was assessed using the pour plate method. Five specimens from each disinfection group were subjected to SL removal assessment using a scanning electron microscope (SEM). Bonding of 7th generation adhesive and composite restoration was performed on ten samples from each group. Artificial aging of the bonded samples was performed followed by SBS and failure mode analysis using a universal testing machine and stereomicroscope respectively. One-way analysis of variance (ANOVA) and Tukey post hoc test were used to analyze the data. ResultsGroup 3 (MB-CNPs-PDT) treated CAD surface unveiled the lowest survival rate (0.12 ± 0.02 CFU/mL) of tested bacteria, maximum SL removal (1.21 ± 0.35), and highest bond strength (13.42 ± 1.05). However, Group 1 (CHX) treated specimens displayed the highest survival rate (0.53 ± 0.11 CFU/mL) with the lowest SL removal (2.24 ± 0.30) and SBS (8.88 ± 0.73 MPa). ConclusionMB-CNPs-PDT appears to be a suitable alternative to CHX for CAD disinfection as it displayed better antibacterial efficacy, SL removal, and SBS with 7th generation single bottle adhesive.

Novel GSK-3 inhibitor based universal dentin bonding system: A comprehensive analysis of dentinal repair and improved bond strength

The aim of the study was to describe the formulation of a novel universal adhesive system, based on a GSK-3 (glycogen synthetase kinase-3) inhibitor (Tideglusib®), and to evaluate its bond strength and dentinal repair capability. Tideglusib® was added to Ultradent Peak Universal Dentin Bonding Agent to make experimental adhesives (0.5 %, 1 %, 2 % final concentration). They were applied to teeth which were sectioned, stored for 24 h, or 2 years then bond strengths measured. Baseline stiffness of bonded dentin beams was tested using the three-point bending test. Animal experiments were performed to provide specimens for microcomputed tomography imaging after adhesive application. Collagen matrix was evaluated using transmission electron microscopy. The cytotoxicity of the modified adhesives was determined using fibroblastic cells. Molecular modelling evaluated binding of the Tideglusib® molecule to active sites on collagen and the adhesive components. TGFβ-1/and BMP-2 in human dentin matrices were measured and interfaces were scanned using SkyScan 2211. Adhesives’ stability tests were done. ResultsRMSD (root mean square deviation) analysis indicated simulation has equilibrated with changes for globular proteins (p < 0.05). Specimens from 0.5 %, and 1 % Tideglusib® groups displayed adhesive penetration with Micro-CT imaging and a significant increase in dentin density was seen. Specimens from the same groups showed cells with large masses of cytoplasm with focal adhesion points. Bond strength decreased significantly (p < 0.05) with increased storage time. Gradual release (p < 0.05) of both TGFβ-1 and BMP-2 from hTDMs with 0.5 % and 1 % Tideglusib® groups occurred and higher elastic moduli (p < 0.05). Collagen-based amide and proline Raman bands were seen in the Tideglusib® groups. ConclusionIncorporation of Tideglusib® in experimental Universal Adhesive System at 1 % improved adhesive bond strength and promoted dentinal repair. Application of Tideglusib® based adhesive conserve mechanical properties of the tooth structure and promote regenerative capability so can be expected to extend the service life of adhesive restorations in clinical situations.

Comparison of Bulk Polymeric Resin Composite and Hybrid Glass Ionomer Cement in Adhesive Class I Dental Restorations: A 3D Finite Element Analysis.

This study aimed to investigate the mechanical behavior of resin composites and hybrid glass ionomer cement in class I adhesive dental restorations under loading and shrinkage conditions. Three CAD models of a mandibular first molar with class I cavities were created and restored with different techniques: a bi-layer of Equia Forte HT with Filtek One Bulk Fill Restorative composite (model A), a single layer of adhesive and Filtek One Bulk Fill Restorative (model B), and a single layer of Equia forte HT (model C). Each model was exported to computer-aided engineering software, and 3D finite element models were created. Models A and B exhibited a similar pattern of stress distribution along the enamel-restoration interface, with stress peaks of 12.5 MPa and 14 MPa observed in the enamel tissue. The sound tooth, B, and C models showed a similar trend along the interface between dentine and restoration. A stress peak of about 0.5 MPa was detected in the enamel of both the sound tooth and B models. Model C showed a reduced stress peak of about 1.2 MPa. A significant stress reduction in 4 mm deep class I cavities in lower molars was observed in models where non-shrinking dental filling materials, like the hybrid glass ionomer cement used in model C, were applied. Stress reduction was also achieved in model A, which employed a bi-layer technique with a shrinking polymeric filling material (bulk resin composite). Model C's performance closely resembled that of a sound tooth.

Comparative Evaluation of Zwitterionic Material, Self-assembling Peptide, and Bioactive Glass Incorporated with MI Varnish for Fluoride, Calcium, and Phosphorus Ion Release, Enamel Remineralization, and Microhardness.

White spot lesions occur when the pathogenic bacteria have broken through the enamel layer. White spot lesions (WSLs) can be treated using a complex approach. The most crucial step is to stop demineralization and biofilm formation and use assorted strategies for remineralization of lesions, thinning, microabrasion, erosion infiltration, adhesive composite resin restorations, and the bonded facets. To evaluate and compare the fluoride, calcium, and phosphorus ion release, remineralizing efficacy, and microhardness of zwitterionic material, self-assembling peptide, and bioactive glass (BGA) incorporated with MI Varnish. The original study was conducted on 60 extracted premolars; the sample size calculated was 10 per group. All samples were divided into four groups-group A, MI Varnish (control), group B, MI Varnish + zwitterionic material, group C, MI Varnish + self-assembling peptide, and group D, MI Varnish + BGA. All these groups were further evaluated and compared for fluoride, calcium, and phorphorus ion release, remineralizing efficacy, and surface microhardness (SMH). Zwitterionic material, when incorporated with MI Varnish showed high fluoride and calcium ion release and high remineralizing efficacy under polarized light microscopy (PLM). BGA, when incorporated with MI Varnish showed high phosphorus ion release and higher values in the evaluation of SMH, followed by zwitterionic material and self-assembling peptide. MI varnish alone had remineralizing properties of WSLs, but when novel materials like zwitterionic ion, self-assembling peptide, and BGA are incorporated, its efficacy increases. Among all zwitterionic ions showed superior results for fluoride and calcium ion release and remineralization and BGA for phosphorus ion release and SMH. Patil SV, Gugwad SC, Devendrappa SN, et al. Comparative Evaluation of Zwitterionic Material, Self-assembling Peptide, and Bioactive Glass Incorporated with MI Varnish for Fluoride, Calcium, and Phosphorus Ion Release, Enamel Remineralization, and Microhardness. Int J Clin Pediatr Dent 2024;17(S-1):S37-S42.

Photoactivated rose bengal-doped TiO2 nanoparticles modified fifth-generation adhesive on the survival rate of Streptococcus mutants and mechanical properties of tooth-colored restorative material to carious dentin.

Assessment of the antimicrobial, micro tensile bond strength (μTBS), and degree of conversion (DC) of fifth-generation adhesive modified using photoactivated 0.5% rose bengal (RB) and photoactivated RB-doped titanium dioxide nanoparticles (TiO2NPs) in different concentrations (2% and 5%) as compared with the unmodified adhesive bonded to the carious affected dentin (CAD). Forty mandibular molars with caries progression up to the middle third of the dentin, as per the International Caries Detection and Assessment System (ICDAS) score of 4 and 5 were included. Specimens were divided into four groups based on etch and rinse adhesive (ERA) modification group 1: unmodified ERA, group 2: photoactivated 0.5% RB photosensitizer (PS) modified ERA, group 3: photoactivated RB-doped 2 wt% TiO2NPs adhesive, group 4: photoactivated RB-doped 5 wt% TiO2NPs adhesive. Followed by adhesive and composite restoration on the CAD surface. All the specimens were thermocycled and an assessment of μTBS and failure pattern analysis was performed. The antibacterial potency of RB and RB-doped TiO2NPs (2% and 5%) followed by their activation using visible light against Streptococcus mutans (S.mutans) were tested. The survival rate of S.mutans was assessed using the Kruskal-Wallis test. The analysis of μTBS involved the use of ANOVA, followed by a post-hoc Tukey honestly significant difference (HSD) multiple comparisons test. Group 1 (Unmodified ERA) (0.52 ± 0.31 CFU/mL) treated samples unveiled the highest means of bacterial survival and lowest μTBS (11.32 ± 0.63 MPa). Nevertheless, group 4: photoactivated RB-doped 5 wt% TiO2NPs adhesive displayed the lowest outcomes of S.mutans survival (0.11 ± 0.02 CFU/mL) and highest bond strength (18.76 ± 1.45 MPa). The photoactivated RB-doped 2 wt% TiO2NPs in adhesive demonstrated promising enhancements in both μTBS and antibacterial efficacy against S.mutans. However, it is noteworthy that this modification led to a decrease in the DC of the adhesive. RESEARCH HIGHLIGHTS: Unmodified ERA-treated samples unveiled the highest bacterial survival and the lowest μTBS. Photoactivated RB-doped 5 wt% TiO2NPs adhesive displayed the lowest S.mutans survival rate and highest bond strength. DC decreased with an increase in concentration of TiO2.

5-Year clinical performance of ceramic onlay and overlay restorations luted with light-cured composite resin

ObjectivesThis prospective clinical trial evaluated the clinical performance of ceramic partial coverage indirect adhesive restorations (PCIARs) in posterior teeth luted with a light-cured composite resin. MethodsFrom April 2016 to January 2017, a total of 60 patients (27 males, 33 females; mean age: 42.2 ± 10.86 years old) received 83 glass-ceramic PCIARs (26 onlay, 57 overlay) made of IPS Emax CAD (Ivoclar Vivadent). All restorations were luted with a light-cured composite resin (Filtek Z250, 3 M ESPE) by two operators. Two independent calibrated examiners blinded to the operators performing the treatment evaluated the restorations at baseline, 1-year, and 5-year following FDI World Dental Federation criteria including esthetic, functional, and biological properties. Data were analyzed with the Friedman test and the Wilcoxon sign test (p < 0.05). ResultsNone of the restorations failed due to fracture or retention loss. One restoration was clinically unsatisfactory because of secondary caries. Marginal staining (p:0.000), marginal adaptation (p:0.018) showed significant differences between 1-year and 5-year recall. ConclusionsThe PCIARs demonstrated excellent clinical performance at 1-year period. The degradation parameters appeared as minor staining and minor irregularities after 5-year, without any affect on the clinical performance. Clinical SignificanceOur findings provide evidence that the clinical performance of PCIARs luted with a light-cured composite resin was clinically acceptable after a five-year evaluation period. Due to secondary caries, only one restoration was considered clinically unsatisfactory. ClinicalTrials registration number: NCT04838483

New Monomer Capable of Dual Chemical Binding with Dentin to Improve Bonding Durability.

The water-rich nature of the dentin bonding microenvironment, coupled with the stresses on the bonding interface, contributes to the hydrolytic degradation of the hybrid layer, resulting in a decline in bonding durability and, ultimately, restoration failure. Currently, the 3-step etch-and-rinse technique remains the gold standard for dentin bonding, and the bonding mechanism mainly involves a physical interaction with little chemical bonding. In this study, we have developed a siloxane-modified polyurethane monomer (SPU) with acrylate and siloxane modifications that chemically binds to both collagen and hydroxyapatite in dentin. Formulated as a bisphenol A-glycidyl methacrylate alternative, the SPU monomer-based adhesive was designed to improve dentin bonding quality and durability. Attenuated total reflection Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscope, and hydroxyproline release assays were performed on SPU-treated collagen, hydroxyapatite, and acid-etched dentin slices to dentin. The physicochemical properties of the configured SPU adhesives were profiled for polymerization behavior, water contact angle, and tensile strain and strength. The bonding effectiveness was assessed through micro-tensile strength, nano-leakage tests conducted on the bonded samples before and after thermal cycle aging. Finally, we further conducted in vivo and in vitro experiments to assess the biocompatibility of adhesives. The results showed that the siloxane groups of SPU monomer could covalently bind to dentin collagen and hydroxyapatite. The incorporation of SPU in the adhesive led to a significant increase in adhesive polymerization (P < 0.05) and tensile strain at break up to 134.11%. Furthermore, the SPU adhesive significantly improved dentin bond strength (P < 0.05), reduced interfacial nano-leakage (P < 0.05), and displayed good biocompatibility. In conclusion, the application of SPU, which achieves dual chemical bonding with dentin, can improve the quality of the hybrid layer, buffer the interfacial stresses, enhance the interfacial resistance to hydrolysis, and provide a feasible strategy to extend the service life of adhesive restorations.

Attitude of Dental Students Toward Rubber Dam Application: A Cross-Sectional Study.

Introduction The rubber dam (RD) system is globally recognized as an indispensable component of dental treatments, ensuring the highest standards of care. The use of RD isolation profoundly impacts the clinical aspects of dental procedures. The aim of this study was to assess the attitudes of dental students toward the use of RD, with an emphasis on evaluating the factors influencing its use among students at Umm Al-Qura University in Makkah city, Kingdom of Saudi Arabia. Methods An online questionnaire was distributed to a population sample of 203 undergraduate dental students in their clinical years at Umm Al-Qura University. Questions covered various aspects, including the frequency of RD use, perceptions of its effectiveness, and prospective intentions for its future use, as well as factors influencing these attitudes. Statistical analysis was performed using SPSS software Version 26 (IBM Corp., Armonk, NY, USA). In addition, the chi-square test and Fisher-Freeman-Halton exact test were used for the comparison of the data at a significance level of p<0.05. Results The questionnaire was completed by 191 participants, with a response rate of 95.5%. Of the students, 189 (99%) used RD during operative procedures for adhesive restorations. Furthermore, 157 (82.2%) students agreed that proper isolation cannot be achieved without RD application. All the advantages of RD application were recognized by 165 (85.9%) of the students. Notably, there was a significant association between the factors limiting the RD application and the students' academic year (p<0.05), with senior students reporting fewer limitations. Responses indicated that 163 (85.3%) of the students received satisfactory training for RD and 165 (86.4%) students had a high intention to continue using RD following graduation. Conclusion Within the limitations of this study, it can be concluded that the results presented a positive attitude toward RD use. However, there is a continued necessity to enhance education and advocate consistent RD application for improved patient care and clinical outcomes.

Multi-acrylamides improve bond stability through collagen reinforcement under physiological conditions

ObjectivesAcrylamides were shown to significantly improve bonding stability in adhesive restorations, but the reinforcement mechanism has not been fully elucidated. We tested the hypothesis that hydrogen bonding reinforcement of the collagen network (with secondary or tertiary acrylamides), as well as degree of crosslinking of the polymer network (with di- or tri-functional acrylamides), can be two of the factors at play. MethodsTwo-step total etch adhesives comprising UDMA (60 wt%) and 40 wt% of: TAAEA, TMAAEA (secondary, tertiary tri-acrylamides), BAAP, DEBAAP (secondary, tertiary di-acrylamides) or HEMA (mono-methacrylate - control) were formulated. Simulated composite restorations (n = 5) were tested after cyclic mechanical and biological (S. mutans biofilm) challenges. Gap formation before and after aging was assessed with SEM imaging. Micro-tensile bond strength (μTBS, n = 6) was assessed after seven-day incubation in water or S. mutans-containing culture medium. Collagen reinforcement was assessed with hydroxyproline assay (n = 10) and rheology (n = 3). Data were analyzed with one-way/two-way ANOVA/Tukey’s test (alpha=5%). ResultsGap formation increased and bond strength decreased for all monomers after biofilm incubation (p < 0.001). Except for DEBAAP, secondary and tertiary di/tri-acrylamides showed lower occlusal gap width values, but no significant differences overall gap length compared to HEMA. μTBS increased for tri-acrylamides compared with HEMA. Samples treated with multi-acrylamides had lower concentration of hydroxyproline (by-product of collagen degradation) (p < 0.001), except for DEBAAP, which showed values close to HEMA (p > 0.05). Dentin shear modulus increased for all acrylamides after 72 h, especially TMAAEA. SignificanceIn general, multi-acrylamides promote collagen reinforcement, leading to reduced gap formation, and stabilize the bond strength under physiological conditions.

Bond Strength of Resin Cement Following Biomimetic Remineralization: An in vitro Study

Objectives This research assessed the efficacy of self-assembling peptide P11-4 (Curodont protect) in promoting biomimetic remineralization of dentin, thereby stabilizing the hybrid layer and enhancing the long-lasting of the resin-dentin bond. Methods Five premolar teeth were longitudinally sectioned to assess dentin microhardness before and after demineralization, as well as after the application of P11-4 (Curodont protect). For the microtensile test, ten premolar teeth were sectioned perpendicular to their long axes. The teeth were assigned to different groups. Following acid etching and rinsing, samples in control group I received no pretreatment, while the prepared dentin surface of group II was treated with 0.1 mL of P11-4 before the placement of the adhesive restoration. All specimens were stored in distilled water at 37 ± 2 °C for 24 hours and then underwent thermocycling. The microtensile test was measured, and the type of bond failure was evaluated. The obtained information, expressed in megapascals, was analyzed using a one-way analysis of variance (ANOVA), followed by Tukey’s multiple post hoc test. Results There was a statistically significant difference in hardness values after demineralization, followed by a significant increase in hardness after the application of P11-4 (Curodont protect) (p &lt; 0.001, effect size = 0.985). No statistically significant difference was found in the microtensile bond strength between the two groups (p = 0.384, effect size = 0.582). Adhesive-type failure was more commonly observed. Conclusion The use of self-assembling peptide P11-4 (Curodont protect) on dentin resulted in higher microhardness than the control group without adversely affecting resin cement bond strength.