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Adhesive resins called 4-META and Panavia have been developed recently. These resins bond to various metals, porcelain, and tooth structure. They have become popular for cementation of unetched resin-bonded prostheses and various other clinical applications. This paper is a brief literature review of the composition, adhesive properties, and clinical uses of the new adhesive resins.
OBJECTIVES: This study aims to analyze the publications that have studied top-cited articles in dentistry. MATERIAL AND METHODS: The study is applied research in terms of the purpose and scientometrics descriptive in terms of type, which has been done using the Retrospective Bibliometric Analysis. To retrieve the 100 most-cited studies in Scopus, an advance search was used. The search results indicate that 33 articles focused on analyzing the 100 most-cited publications on oral and dental subjects. The bibliographic information, including author, journal, country, institution, citation count, and citation density was analyzed. Then the full text of the articles was reviewed to identify the most productive journal, country, and institute in publishing the 100 most-cited articles and also article type, study design, level of evidence, and the most important subjects among the 100 most-cited papers. RESULTS: In these 33 articles, the topics of 3300 most-cited articles were introduced, as well as the introduction of the core journals, countries, and institutes in publishing top-cited articles. The most common research topics in the field of dentistry cover a range of dental public health and pediatric dentistry to adhesive restorative dentistry and implantology. Dental materials, oral medicine, and pathology seem like inseparable topics of common research in dentistry. J Dent Res, which was mentioned in nine articles, was introduced as the journal with the publication of articles of highest citation. J Clin Periodontol and Oral Surgery, Oral Medicine, Oral Pathology, and Oral Radiology were in the second place, being mentioned in five articles. The USA, and two institutions the University of Texas, and the University of Michigan are orderly core country and institute for the production of most-cited articles. CONCLUSION: Researchers and specialists can get familiar with the most productive author, journals, countries, and different institutes for publishing high-quality articles in the field of oral and dental subjects by the means of the results of this article. Furthermore, the results of this study ranked the most cited article topics, which are of interest for publication, demonstrating the future map road oral and dental research.
Several studies have shown that the dentin-resin interface is unstable due to poor infiltration of resin monomers into the demineralized dentin matrix. This phenomenon is related to the incomplete infiltration of the adhesive system into the network of exposed collagen fibrils, mainly due to the difficulty of displacement and subsequent replacement of trapped water between interfibrillar spaces, avoiding adequate hybridization within the network of collagen fibrils. Thus, unprotected fibrils are exposed to undergo denaturation and are susceptible to cyclic fatigue rupture after being subjected to repetitive loads during function. The aqueous inclusions within the hybrid layer serve as a functional medium for the hydrolysis of the resin matrix, giving rise to the activity of esterases and collagenolytic enzymes, such as matrix metalloproteinases, which play a fundamental role in the degradation process of the hybrid layer. Achieving better interdiffusion of the adhesive system in the network of collagen fibrils and the substrate stability in the hybrid layer through different strategies are key events for the interfacial microstructure to adequately function. Hence, it is important to review the factors related to the mechanisms of degradation and stabilization of the hybrid layer to support the implementation of new materials and techniques in the future. The enzymatic degradation of collagen matrix, together with resin leaching, has led to seeking strategies that inhibit the endogenous proteases, cross-linking the denudated collagen fibrils and improving the adhesive penetration removing water from the interface. Some of dentin treatments have yielded promising results and require more research to be validated. A longer durability of adhesive restorations could resolve a variety of clinical problems, such as microleakage, recurrent caries, postoperative sensitivity, and restoration integrity.
OBJECTIVES: To evaluate the effect of surface treatments and bonding systems on the repair bond strength between composite materials after one and 12 months of storage, using an improved microtensile test method. METHODS: A total of 72 composite cylinders (Tetric Evo Ceram, Ivoclar) were fabricated, stored in distilled water for two weeks followed by thermal cycling (5000 times between 5°C and 55°C), and served as substrate. The cylinders were mechanically roughened using 320-grit silicon carbide sandpaper, etched with 37% phosphoric acid gel, rinsed with water, and divided equally into three experimental groups: group 1, unchanged surface; group 2, sandblasting of the surface (CoJet tribochemical silica sand, 3M ESPE; Microetcher II, Danville Engineering Inc); and group 3, surface silane coating (Bis-Silane, BISCO Inc). Eight control cylinders were prepared and underwent similar aging as the substrate. Each experimental group was divided into subgroups that received the following bonding systems: one-step self-etching adhesive (AdheSE One, Ivoclar Vivadent), two-step self-etching adhesive (Clearfil SE, Kuraray America), and three-step etch-and-rinse adhesive (Adper Scotchbond Multi-Purpose, 3M ESPE). Fresh composite (Tetric Evo Ceram, Ivoclar) was placed and cured on top of the prepared substrate cylinders. The specimens were placed in distilled water for a week and thermocycled the same way as before. Eight composite control cylinders were also stored and thermocycled for the same period of time. Half of the cylinders in each test group were tested at one month and the second half at 12 months. The cylinders were serially sectioned in an automatic cutting machine, producing 10 to 20 1.1 × 1.1-mm test specimen beam from each cylinder. Specimens were prepared for microtensile testing and the tensile strength calculated based on the force at fracture and specimen dimension. The fracture surfaces were examined under a stereomicroscope and the type of fracture noted. RESULTS: The mean tensile strength of composite control was 54.5 ± 6.0 MPa at one month and 49.6 ± 5.1 MPa at 12 months. The mean tensile strength for the repaired groups ranged from 26.4 ± 6.8 MPa to 49.9 ± 10.4 MPa at one month and 21.2 ± 9.9 to 41.3 ± 7.5 at 12 months. There was a statistical difference between all groups (p<0.05) at one month. This difference was less pronounced at 12 months. The highest repair strength was obtained in the group having a silane-coated surface and Clearfil, the two-step self-etching adhesive. Clearfil also had the highest repair strength within each surface treatment group. There was a tendency for lower tensile strength at 12 months compared with one month. Most fractures were of the adhesive type; the highest number of cohesive fractures, 16% at one month and 12% at 12 months, were in groups with the highest tensile strength. CONCLUSION: The best repair bond strength was achieved by using freshly mixed silane solution on the substrate in addition to an adhesive, rendering a thin bonding layer.
This narrative review will focus on a number of contemporary considerations relating to the restoration of root filled teeth and future directions for research. Clinicians are now more than ever, aware of the interdependence of the endodontic and restorative aspects of managing root filled teeth, and how these aspects of treatment are fundamental to obtaining the best long-term survival. To obtain the optimal outcomes for patients, clinicians carrying out endodontic treatment should have a vested interest in the restorative phase of the treatment process, as well as an appreciation for the structural and biomechanical effects of endodontic-restorative procedures on restoration and tooth longevity. Furthermore, the currently available research, largely lacks appreciation of occlusal factors in the longevity of root filled teeth, despite surrogate outcomes demonstrating the considerable influence this variable has. Controversies regarding the clinical relevance of minimally invasive endodontic and restorative concepts are largely unanswered with respect to clinical data, and it is therefore, all too easy to dismiss these ideas due to the lack of scientific evidence. However, conceptually, minimally invasive endodontic-restorative philosophies appear to be valid, and therefore, in the pursuit of improved clinical outcomes, it is important that the efficacies of these treatment protocols are determined. Alongside an increased awareness of the preservation of tooth structure, developments in adhesive bonding, ceramic materials and the inevitable integration of digital dentistry, there is also a need to evaluate the efficacy of new treatment philosophies and techniques with well-designed prospective clinical studies.
I do not remember a time during my dental career when direct resin restorations were not being disparaged by someone. Some of the expressed concerns have validity. Certainly the earlier composite resins offered little wear resistance or ability to predictably create a bonded interface. The chemical activation system used in early materials also limited the ability of a practitioner to form and sculpt restorations.I remember being taught that the placement of a composite resin restoration should include the same level of care and attention to detail provided to direct gold restorations. I have held the opinion that many of the problems associated with composite resin restorations can be attributed to approaching their placement in a way that mimics the approach taken when placing amalgam, a material that is much more forgiving of less-than-optimal handling.An important issue in the placement of light-activated composite resin is the amount and type of light energy that is actually being received by the material. Inadequate light curing can easily result in compromised restorative material properties, compromises that likely have a negative influence on restoration longevity. It has been well documented that, worldwide, many offices have been using inadequate amounts of energy and less-than-optimal technique and are delivering inadequate amounts of energy when light curing resins.1-9 If that is the case, then it should be no surprise to anyone when reading reports about the substandard performance of posterior composite resin restorations.10-13More than 40 key opinion leaders and company scientists met at Dalhousie University in May 2014 to discuss ways to address issues surrounding light curing. Arranged by Dr. Richard B. Price, the symposium participants included:The symposium received support and active participation from Benco, BISCO, BlueLight Analytics, DENTSPLY, Gigahertz-Optik, Henry Schein, Heraeus-Kulzer, Ivoclar Vivadent, Kerr, Patterson Dental, SDI, 3M-ESPE, and Ultradent.The group adopted a glossary of terms that are based on the International System of Units (SI) definitions associated with light technology and is encouraging the use of them during communication on the subject (Table 1).14 In addition, a consensus statement reflecting areas of agreement within the group was drafted and is included here as Figure 1.Inadequate light curing can easily result in compromised restorative material properties. These compromises will likely have a negative influence on restoration longevity.The included guidelines are provided for the benefit of your patients and are simultaneously being published here and in the following journals: Journal of Adhesive Dentistry, Dental Materials, and Journal of the Canadian Dental Association.
All-ceramic restorations are the foundation of modern restorative aesthetic dentistry. The industry for dental materials now provides a large selection of biomaterials with a range of constantly improving qualities. Although this is undoubtedly advantageous, the vast array of materials may confuse even experienced dentists. Even if recently the demand of digital dentistry in daily dental practice has significantly increased, due to a lack of understanding concerning cementation techniques, which are different for each type of ceramic used, dentists are continuing to be hesitant to utilise these various CAD/CAM materials. This study analysed 58 articles from 2008 to 2025, focusing on narrative, comprehensive, and systematic reviews and in vitro studies on dental dentistry materials. English articles were included, but non-English articles and case reports were excluded. The analysis included articles from all journal categories, ensuring adherence to inclusion and exclusion criteria. The aim of the research is to assess material classifications and properties that guide practices concerning the adhesive cementation of all-ceramic restorations. In order to provide a clear overview of the composition, characteristics, clinical considerations, and current trends of contemporary dental materials, as well as some recommendations for future research in this area that would be relevant to dentists and the scientific community, the authors of the paper were guided by this structure when writing the article content. The key is to ensure the aesthetics, resistance, and long-term clinical success of the treatment plan by providing dental professionals with clear, accurate information and instructions about resin-luting materials and indirect restoration materials.
The replacement of a restoration is one of the most common procedures in dentistry. However, the criteria for such intervention, excluding catastrophic failure and persistent discomfort and pain, continue to be the subject of considerable debate. The decision-making process remains subjective on the part of the treating clinician, while the evidence base for refurbishment and repair rather than replacement for the management of defective and failing restorations continues to grow and strengthen. This article, prepared as an Academy of Operative Dentistry European Section consensus publication, reviews existing criteria for the replacement of restorations and encourages practitioners to shift, if not already doing so, to considering the replacement of a restoration as a last resort rather than as a prudent action to be taken if in any doubt about clinical acceptability. Further research in the area, spanning the risk assessment of defective and failing restorations and new diagnostic tools and processes, together with work to enhance the evidence base of restoration repair vs replacement, would be of immense value.
OBJECTIVES: This study evaluated the effect of the application mode on the microtensile resin-dentin bond strength (microTBS) and silver nitrate uptake (SNU) of three one-step self-etch adhesives systems (Clearfil S3 Bond [S3], Xeno III [XE] and Adper Prompt L-Pop [AD]). MATERIALS AND METHODS: The occlusal enamel of 30 caries-free extracted molars was removed with a slow-speed diamond saw under copious water-cooling in order to expose a flat dentin surface. The adhesives were applied passively or with agitation. After light-curing (600 mW/cm2 for 10 seconds), composite buildups were constructed incrementally and the specimens were stored in water (37 degrees C/24 hours). The specimens were longitudinally sectioned in the "x" and "'y" direction to obtain bonded sticks (0.8 mm2) to be tested immediately in tension at 0.5 mm/minute. For SNU, two bonded sticks from each tooth were coated with nail varnish, placed in silver nitrate and polished down with SiC paper. The microTBS and SNU data were submitted to two-way ANOVA and Tukey's test (alpha=0.05). RESULTS: Regarding the microTBS, only the main factor mode of application was statistically significant (p = 0.01). All adhesives showed higher microTBS when applied with agitation. Regarding SNU, only the main factor adhesive was statistically significant (p = 0.001). A higher amount of silver nitrate uptake, located in both the hybrid and adhesive layer, occurred for AD, regardless of the mode of application. CONCLUSIONS: Application with agitation on the dentin surface is a clinical tool capable of improving the resin-dentin bond strength of one-step self-etch adhesives; however, this clinical approach does not improve the hybrid layer resistance to silver nitrate uptake.
Clinicians often face dilemmas regarding the most appropriate way to restore a tooth following root canal treatment. Whilst there is established consensus on the importance of the ferrule effect on the predictable restoration of root filled teeth, other factors, such as residual tooth volume, tooth location, number of proximal contacts, timing of the definitive restoration and the presence of cracks, have been reported to influence restoration and tooth survival. The continued evolution of dental materials and techniques, combined with a trend towards more conservative endodontic-restorative procedures, prompts re-evaluation of the scientific literature. The aim of this literature review was to provide an updated overview of the existing clinical literature relating to the restoration of root filled teeth. An electronic literature search of the PubMed, Ovid (via EMBASE) and MEDLINE (via EMBASE) databases up to July 2020 was performed to identify articles that related the survival of root filled teeth and/or restoration type. The following and other terms were searched: restoration, crown, onlay, root canal, root filled, post, clinical, survival, success. Wherever possible, only clinical studies were selected for the literature review. Full texts of the identified articles were independently screened by two reviewers according to pre-defined criteria. This review identifies the main clinical factors influencing the survival of teeth and restorations following root canal treatment in vivo and discusses the data related to specific restoration type on clinical survival.
This study compared the progression of sealed initial enamel lesions penetrated with a fissure sealant (Helioseal, Vivadent) or various adhesives (Heliobond, Excite, Vivadent; Resulcin, Merz; Solobond M, Voco; Prompt L-Pop, 3M-ESPE) after exposure to a demineralizing solution, in vitro. From 27 bovine teeth, 54 enamel specimens were prepared and covered with nail varnish (control), thus obtaining three windows for treatment. After demineralization (pH 5.0; 14 days), two of the windows (A, B) were etched with phosphoric acid (20%; 5 seconds); whereas, the third area served as the control (C). The specimens were divided randomly into six groups (n=9), and the material was applied (90 seconds) either once (A) or twice (B). Light-curing followed each application. Half of the area of each specimen window was then covered with nail varnish, and the samples were again stored in the demineralizing solution (pH 5.0; 14 days). The specimens were cut perpendicular to the surface, and both enamel slabs were studied after infiltration using a fluorescent, low viscous resin (VIRIN) and confocal microscopy (CLSM). Lesion depths were calculated (ImageJ) from the surface to that point in the lesion where the grey values clearly changed to a darker grey. After demineralization, mean lesion depths (SD) (14 days) were measured at 105 (21) microm. The second demineralization led to a mean progression of the lesion depths of 52 (31)%. Adper Prompt L-Pop and Solobond M could not significantly prevent lesion progression after a single application (p > 0.05; t-test); however, the second application of Solobond M significantly decreased lesion progression (p < 0.05; t-test). Helioseal, Heliobond, Resulcin Monobond and Excite showed significantly better inhibition of the demineralization compared to the other materials (p < 0.05; Bonferroni). It can be concluded that the penetration of adhesives into initial lesions inhibited a further demineralization in vitro.
The current study evaluated the effect of 2% chlorhexidine digluconate (CHX) on the immediate and six-month resin-dentin bond strength (BS) and nanoleakage pattern (NL) of etch-and-rinse adhesives when applied in aqueous or associated to the phosphoric acid conditioner. The occlusal enamel of 42 caries-free extracted molars was removed in order to expose a flat dentin surface. In groups 1 and 2 (control-C), the surfaces were acid etched with conventional phosphoric acid, and the adhesives Prime&Bond NT (PB) and Adper Single Bond 2 (SB) were applied after rinsing, drying and rewetting with water. In groups 3 and 4 (Ac/CHX), the adhesives were applied in a similar manner, however, a 2% CHX-containing acid was previously applied. In groups 5 and 6 (CHX), the adhesives were applied according to the control group; however, the rewetting procedure was performed with an aqueous solution of 2% CHX for 60 seconds. Composite buildups (Opallis, FGM) were constructed incrementally, and the specimens were longitudinally sectioned in the "x" and "y" directions to obtain bonded sticks (0.8 mm2) to be tested in tension at 0.5 mm/minute immediately or after six months of water storage. For NL, two bonded sticks from each tooth were coated with nail varnish, placed in silver nitrate and polished down with SiC paper. Resin-dentin interfaces were analyzed by EDX-SEM. The BS and NL data from each adhesive was submitted to two-way repeated measures ANOVA and Tukey's test (alpha=0.05). After six months of water storage, significant reductions in BS were observed for both adhesives in the control group (p<0.05). When Ac/CHX or CHX was used, no significant reductions in BS were observed for both systems. Nanoleakage was more evident in the control group than in the experimental groups (p<0.05), even after six months. The use of CHX in an aqueous solution or associated with the acid conditioner was effective for reducing degradation of resin-dentin bonds after six months of water storage.
In dentin bonding, contemporary dental adhesive systems rely on formation of the hybrid layer, a biocomposite containing dentin collagen and polymerized resin adhesive. They are usually able to create at least reasonable integrity of the hybrid layer with high immediate bond strength. However, loss of dentin-bonded interface integrity and bond strength is commonly seen after aging both in vitro and in vivo. This is due to endogenous collagenolytic enzymes, matrix metalloproteinases, and cysteine cathepsins, responsible for the time-dependent loss of hybrid layer collagen. In addition, the hydrophilic nature of adhesive systems creates problems that lead to suboptimal hybrid layers. These problems include, for example, insufficient resin impregnation of dentin, phase separation, and a low rate of polymerization, all of which may reduce the longevity of the bonded interface. Preservation of the collagen matrix integrity by inhibition of endogenous dentin proteases is key to improving dentin bonding durability. Several approaches to retain the integrity of the hybrid layer and to improve the long-term dentin bond strength have been tested. These include the use of enzyme inhibitors, either separately or as incorporated into the adhesive resins; increase of collagen resistance to enzymatic degradation; and elimination of water from the interface to slow down or eliminate hydrolytic loss of the hybrid layer components. This review looks at the principles, current status, and future of the different techniques designed to prevent the loss of hybrid layer and bond strength.
This study evaluated the effect of 2% chlorhexidine digluconate (CHX) used as a therapeutic primer on the long-term bond strengths of two etch-and-rinse adhesives to normal (ND) and caries-affected (CAD) dentin. Forty extracted human molars with coronal carious lesions, surrounded by normal dentin, were selected for this study. The flat surfaces of two types of dentin (ND and CAD) were prepared with a water-cooled high-speed diamond disc, then acid-etched, rinsed and air-dried. In the control groups, the dentin was re-hydrated with distilled water, blot-dried and bonded with a three-step (Scotchbond Multi-Purpose-MP) or two-step (Single Bond 2-SB) etch-and-rinse adhesive. In the experimental groups, the dentin was rehydrated with 2% CHX (60 seconds), blot-dried and bonded with the same adhesives. Resin composite build-ups were made. The specimens were prepared for microtensile bond testing in accordance with the non-trimming technique, then tested either immediately or after six-months storage in artificial saliva. The data were analyzed by ANOVA/Bonferroni tests (alpha = 0.05). CHX did not affect the immediate bond strength to ND or CAD (p > 0.05). CHX treatment significantly lowered the loss of bond strength after six months as seen in the control bonds for ND (p < 0.05), but it did not alter the bond strength of CAD (p > 0.05). The application of MP on CHX-treated ND or CAD produced bonds that did not change over six months of storage.
The aim of this study was to measure the shear bond strength of different adhesive systems to Biodentine with different time intervals. Eighty specimens of Biodentine were prepared and divided into 8 groups. After 12 minutes, 40 samples were randomly selected and divided into 4 groups of 10 each: group 1: (etch-and-rinse adhesive system) Prime & Bond NT; group 2: (2-step self-etch adhesive system) Clearfil SE Bond; group 3: (1-step self-etch adhesive systems) Clearfil S(3) Bond; group 4: control (no adhesive). After the application of adhesive systems, composite resin was applied over Biodentine. This procedure was repeated 24 hours after mixing additional 40 samples, respectively. Shear bond strengths were measured using a universal testing machine, and the data were subjected to 1-way analysis of variance and Scheffé post hoc test. No significant differences were found between all of the adhesive groups at the same time intervals (12 minutes and 24 hours) (P > .05). Among the two time intervals, the lowest value was obtained for group 1 (etch-and-rinse adhesive) at a 12-minute period, and the highest was obtained for group 2 (two-step self-etch adhesive) at a 24-hour period. The placement of composite resin used with self-etch adhesive systems over Biodentine showed better shear bond strength.
UNLABELLED: This investigation assessed the effectiveness of alternative treatments for the replacement of amalgam and resin-based composite restorations. Sixty-six patients (age 18 to 80 years, mean = 26.6) with 271 (amalgam [n = 193] and resin-based composite [n = 78]) defective restorations were randomly assigned to one of five different treatment groups: A) Repair (n = 27); B) Sealing of margins (n = 48); C) Refurbishing (n = 73); D) Replacement (n = 42) and E) Untreated (n = 81). USPHS/Ryge criteria were used to determine the quality of the restorations. Two calibrated examiners (Cohen's Kappa 0.74) assessed the restorations independently at the beginning of the study (baseline) and at two years after treatment using seven parameters from the USPHS/Ryge criteria (Marginal Adaptation, Anatomic Form, Roughness, Marginal Stain, Occlusal Contact, Secondary Caries and Luster). RESULTS: Two-hundred and fifty-six restorations (178 amalgam and 78 resin-based composite) were examined at the two-year recall exam. The sealing of marginal defects showed significant improvements in marginal adaptation (p < 0.05). Refurbishing of the defective restorations significantly improved anatomic form (p < 0.0001), luster (p < 0.016), marginal adaptation (p < 0.003) and roughness (p < 0.0001). The repair significantly improved anatomic form (p < 0.002) and marginal stain (p < 0.002). Replacement showed significant improvements for all parameters (p < 0.05). The Untreated group showed significant deterioration on marginal adaptation (p < 0.013). CONCLUSIONS: The two-year recall examination showed that sealant, repair and refurbishing treatments improved the clinical properties of defective amalgam and resin-based composite restorations by increasing the longevity of the restorations with minimal intervention.
PURPOSE: Universal bonding agents have been introduced for use as self-etch or etch-and-rinse adhesives depending on the dental substrate and clinician's preference. The purpose of this study was to evaluate the shear bond strength (SBS) of composite to enamel using universal adhesives compared to a self-etch adhesive when applied in self-etch and etch-and-rinse modes over time. METHODS AND MATERIALS: Extracted human third molars were used to create 120 enamel specimens. The specimens were ground flat and randomly divided into three groups: two universal adhesives and one self-etch adhesive. Each group was then subdivided, with half the specimens bonded in self-etch mode and half in etch-and-rinse mode. The adhesives were applied as per manufacturers' instructions, and composite was bonded using a standardized mold and cured incrementally. The groups were further divided into two subgroups with 10 specimens each. One subgroup was stored for 24 hours and the second for six months in 37°C distilled water and tested in shear. Failure mode was also determined for each specimen. RESULTS: A three-way analysis of variance (ANOVA) found a significant difference between groups based on bonding agent (p<0.001) and surface treatment (p<0.001) but not on time (p=0.943), with no significant interaction (p>0.05). Clearfil SE in etch-and-rinse and self-etch modes had more mixed fractures than either universal adhesive in either mode. CONCLUSIONS: Etching enamel significantly increased the SBS of composite to enamel. Clearfil SE had significantly greater bond strength to enamel than either universal adhesive, which were not significantly different from each other.
The setting of dental composites is accompanied by significant polymerization contraction, resulting in the generation of stresses within the material and at the tooth-restoration interface. These stresses can have a deleterious effect on marginal integrity if they exceed the adhesive strength of the restorative, as well as on the properties of the composite. It has been determined that several factors affect these stresses, including the polymerization rate of the composite, its formulation, including filler and monomer composition and the constraints imposed by the geometry of the cavity preparation. Many strategies have been developed to reduce the effect of these stresses. Changes in the formulation of the composite have included experimentation with a variety of stress relieving additives, modified catalyst compositions and alternative monomer systems. Modifications to the placement techniques have included the use of incremental curing, altered light activation schemes and resilient liners. This manuscript will review many of the important scientific and clinical issues relating to the generation and quantitation of the stresses produced in dental composites during curing.
OBJECTIVES: This study evaluated mechanically and ultra-morphologically 11 different adhesive systems bonded to dentin. METHODS: The microtensile bond strength (microTBS) of 11 contemporary adhesives, including two three-step etch&rinse, three two-step etch&rinse, two two-step self-etch and four one-step self-etch adhesives to dentin, were measured. The resultant interfacial ultra-structure at dentin was characterized by transmission electron microscopy (TEM). Human third molars had their superficial dentin surface exposed, after which a standardized smear layer was produced using a medium-grit diamond bur. The selected adhesives were applied according to their respective manufacturer's instructions for microTBS measurement after storage in water at 37 degrees C for 24 hours or for TEM interfacial characterization. RESULTS: The microTBS varied from 11.1 to 63.6 MPa; the highest bond strengths were obtained with the three-step etch&rinse adhesives and the lowest with one-step self-etch adhesives. TEM evaluation showed very different interaction patterns, especially for the self-etch adhesives. "Mild" self-etch adhesives demineralized the dentin surface sufficiently to provide micro-mechanical retention, while preserving hydroxyapatite within the hybrid layer to enable additional chemical interaction. CONCLUSIONS: When bonded to dentin, the adhesives with simplified application procedures (in particular, one-step self-etch adhesives) still underperform as compared to conventional three-step adhesives. "Mild" two-step self-etch adhesives that provide additional chemical bonding appear to most optimally combine bonding effectiveness with a simplified application protocol.
OBJECTIVE: This in vitro study assessed the neutralizing effect of grape seed extract (oligomeric proanthocyanidin complexes [OPCs]) on the bond strength of bleached enamel. MATERIALS AND METHODS: Labial enamel surfaces of 70 extracted human maxillary central incisors were randomly divided into four groups based on the antioxidant used as follows: Group I (n=20): bleaching with 38% hydrogen peroxide gel for 10 minutes, without the use of an antioxidant; Group II (n=20): bleaching followed by the use of 10% sodium ascorbate solution; Group III (n=20): bleaching followed by the use of 5% proanthocyanidin solution; and Group IV (n=10): control group in which no bleaching was done. Groups I, II, and III were further subdivided into two subgroups of 10 teeth each, based on whether composite build-up was done immediately (subgroup A) or after a delay of 2 weeks (subgroup B) post bleaching. Shear bond strength of the specimens was tested under a universal testing machine. The data were tabulated and statistically analyzed. RESULTS: Significantly higher shear bond strength values were observed in teeth treated with 10% sodium ascorbate (Group II) and 5% proanthocyanidin (Group III) as compared with the control group (Group IV). Among the antioxidants used, teeth treated with proanthocyanidin showed significantly higher shear bond strength values than those treated with sodium ascorbate. CONCLUSION: It can be concluded that the use of grape seed extract prior to bonding procedures on bleached enamel completely neutralizes the deleterious effects of bleaching and increases the bond strength significantly.