Guidance on posterior resin composites: Academy of Operative Dentistry - European Section.

There have been many developments in operative dentistry in recent years, including a progressive shift to the use of resin composites, rather than dental amalgam, in the restoration of posterior teeth. This shift allows the adoption of minimal intervention approaches, thereby helping to conserve and preserve remaining tooth tissues and structures. This paper presents the position of the Academy of Operative Dentistry European Section (AODES) in relation to posterior resin composites. The AODES considers adhesively bonded resin composites of suitable composition and properties to be the "material of choice" for use in direct minimal intervention approaches to the restoration of posterior teeth. In so doing, the AODES emphasises the importance of the practice of evidence-based minimal intervention dentistry, including the use of refurbishment and repair techniques to extend the longevity of restorations. Guidance, based on best available evidence, has been made in relation to certain aspects of resin composite placement techniques in posterior teeth.

FDI World Dental Federation - clinical criteria for the evaluation of direct and indirect restorations. Update and clinical examples.

In 2007, new clinical criteria were approved by the FDI World Dental Federation and simultaneously published in three dental journals. The criteria were categorized into three groups: esthetic parameters (four criteria), functional parameters (six criteria), and biological parameters (six criteria). Each criterion can be expressed with five scores, three for acceptable and two for non-acceptable (one for reparable and one for replacement). The criteria have been used in several clinical studies since 2007, and the resulting experience in their application has led to a requirement to modify some of the criteria and scores. The two major alterations involve staining and approximal contacts. As staining of the margins and the surface have different causes, both phenomena do not appear simultaneously. Thus, staining has been differentiated into marginal staining and surface staining. The approximal contact now appears under the name "approximal anatomic form" as the approximal contour is a specific, often non-esthetic issue that cannot be integrated into the criterion "esthetic anatomical form". In 2008, a web-based training and calibration tool called e-calib (www.e-calib.info) was made available. Clinical investigators and other research workers can train and calibrate themselves interactively by assessing clinical cases of posterior restorations, which are presented as high quality pictures. Currently, about 300 clinical cases are included in the database which is regularly updated. Training for 8 of the 16 clinical criteria is available in the program: "Surface luster"; "Staining (surface, margins)"; "Color match and translucency"; "Esthetic anatomical form"; "Fracture of material and retention"; "Marginal adaptation"; "Recurrence of caries, erosion, abfraction"; and "Tooth integrity (enamel cracks, tooth fractures)". Typical clinical cases are presented for each of these eight criteria and their corresponding five scores.

FDI World Dental Federation: clinical criteria for the evaluation of direct and indirect restorations-update and clinical examples.

In 2007, new clinical criteria were approved by the FDI World Dental Federation and simultaneously published in three dental journals. The criteria were categorized into three groups: esthetic parameters (four criteria), functional parameters (six criteria) and biological parameters (six criteria). Each criterion can be expressed with five scores, three for acceptable and two for non-acceptable (one for reparable and one for replacement). The criteria have been used in several clinical studies since 2007, and the resulting experience in their application has led to a requirement to modify some of the criteria and scores. The two major alterations involve staining and approximal contacts. As staining of the margins and the surface has different causes, both phenomena do not appear simultaneously. Thus, staining has been differentiated into marginal staining and surface staining. The approximal contact now appears under the name "approximal anatomic form" as the approximal contour is a specific, often non-esthetic issue that cannot be integrated into the criterion "esthetic anatomical form". In 2008, a web-based training and calibration tool called e-calib ( www.e-calib.info ) was made available. Clinical investigators and other research workers can train and calibrate themselves interactively by assessing clinical cases of posterior restorations which are presented as high-quality pictures. Currently, about 300 clinical cases are included in the database which is regularly updated. Training for eight of the 16 clinical criteria is available in the program: "Surface lustre"; "Staining (surface, margins)"; "Color match and translucency"; Esthetic anatomical form"; "Fracture of material and retention"; "Marginal adaptation"; "Recurrence of caries, erosion, abfraction"; and "Tooth integrity (enamel cracks, tooth fractures)". Typical clinical cases are presented for each of these eight criteria and their corresponding five scores.

Recommendations for conducting controlled clinical studies of dental restorative materials. Science Committee Project 2/98--FDI World Dental Federation study design (Part I) and criteria for evaluation (Part II) of direct and indirect restorations including onlays and partial crowns.

About 35 years ago, Ryge provided a practical approach to the evaluation of the clinical performance of restorative materials. This systematic approach was soon universally accepted. While that methodology has served us well, a large number of scientific methodologies and more detailed questions have arisen that require more rigor. Current restorative materials have vastly improved clinical performance, and any changes over time are not easily detected by the limited sensitivity of the Ryge criteria in short-term clinical investigations. However, the clinical evaluation of restorations not only involves the restorative material per se but also different operative techniques. For instance, a composite resin may show good longevity data when applied in conventional cavities but not in modified operative approaches. Insensitivity, combined with the continually evolving and nonstandard investigator modifications of the categories, scales, and reporting methods, has created a body of literature that is extremely difficult to interpret meaningfully. In many cases, the insensitivity of the original Ryge methods leads to misinterpretation as good clinical performance. While there are many good features of the original system, it is now time to move on to a more contemporary one. The current review approaches this challenge in two ways: (1) a proposal for a modern clinical testing protocol for controlled clinical trials, and (2) an in-depth discussion of relevant clinical evaluation parameters, providing 84 references that are primarily related to issues or problems for clinical research trials. Together, these two parts offer a standard for the clinical testing of restorative materials/procedures and provide significant guidance for research teams in the design and conduct of contemporary clinical trials. Part 1 of the review considers the recruitment of subjects, restorations per subject, clinical events, validity versus bias, legal and regulatory aspects, rationales for clinical trial designs, guidelines for design, randomization, number of subjects, characteristics of participants, clinical assessment, standards and calibration, categories for assessment, criteria for evaluation, and supplemental documentation. Part 2 of the review considers categories of assessment for esthetic evaluation, functional assessment, biological responses to restorative materials, and statistical analysis of results. The overall review represents a considerable effort to include a range of clinical research interests over the past years. As part of the recognition of the importance of these suggestions, the review is being published simultaneously in identical form in both the Journal of Adhesive Dentistry and Clinical Oral Investigations. Additionally, an extended abstract will be published in the International Dental Journal, giving a link to the web full version. This should help to introduce these considerations more quickly to the scientific community.

A prospective ten-year clinical trial of porcelain veneers.

PURPOSE: The aim of this in vivo study was to evaluate the clinical performance of porcelain veneers after 5 and 10 years of clinical service. MATERIALS AND METHODS: A single operator placed porcelain laminates on 87 maxillary anterior teeth in 25 patients. All restorations were recalled at 5 years and 93% of the restorations at 10 years. Clinical performance was assessed in terms of esthetics, marginal integrity, retention, clinical microleakage, caries recurrence, fracture, vitality, and patient satisfaction. Failures were recorded either as "clinically unacceptable but repairable" or as "clinically unacceptable with replacement needed". RESULTS: Porcelain veneers maintained their esthetic appearance after 10 years of clinical service. None of the veneers were lost. The percentage of restorations that remained "clinically acceptable" (without need for intervention) significantly decreased from an average of 92% (95 CI: 90% to 94%) at 5 years to 64% (95 CI: 51% to 77%) at 10 years. Fractures of porcelain (11%) and large marginal defects (20%) were the main reason for failure. Marginal defects were especially noticed at locations where the veneer ended in an existing composite filling. At such vulnerable locations, severe marginal discoloration (19%) and caries recurrence (10%) were frequently observed. Most of the restorations that present one or more "clinically unacceptable" problems (28%) were repairable. Only 4% of the restorations needed to be replaced at the 10-year recall. CONCLUSION: It was concluded that labial porcelain veneers represent a reliable, effective procedure for conservative treatment of unesthetic anterior teeth. Occlusion, preparation design, presence of composite fillings, and the adhesive used to bond veneers to tooth substrate are covariables that contribute to the clinical outcome of these restorations in the long-term.

Microtensile bond strength of eleven contemporary adhesives to enamel.

PURPOSE: To compare the microtensile bond strength (microTBS) to enamel of 10 contemporary adhesives, including three one-step self-etch systems, four two-step self-etch systems and three two-step total-etch systems, with that of a conventional three-step total-etch adhesive. METHODS: Resin composite (Z100, 3M) was bonded to flat, #600-grit wet-sanded enamel surfaces of 18 extracted human third molars using the adhesives strictly according to the respective manufacturer's instructions. After storage overnight in 37 degrees C water, the bonded specimens were sectioned into 2-4 thin slabs of approximately 1 mm thickness and 2.5 mm width. They were then trimmed into an hourglass shape with an interface area of approximately 1 mm2, and subsequently subjected to microTBS-testing with a cross-head speed of 1 mm/minute. RESULTS: The microTBS to enamel varied from 3.2 MPa for the experimental one-step self-etch adhesive PQ/Universal (self-etch) to 43.9 MPa for the two-step total-etch adhesive Scotchbond 1. When compared with the conventional three-step total-etch adhesive OptiBond FL, the bond strengths of most adhesives with simplified application procedures were not significantly different, except for two one-step self-etch adhesives, experimental PQ/Universal (self-etch) and One-up Bond F, that showed lower bond strengths. Specimen failures during sample preparation were recorded for the latter adhesives as well.

Buonocore memorial lecture. Adhesion to enamel and dentin: current status and future challenges.

Bonding to tooth tissue can be achieved through an "etch&rinse," "self-etch" or "glass-ionomer" approach. In this paper, the basic bonding mechanism to enamel and dentin of these three approaches is demonstrated by means of ultramorphological and chemical characterization of tooth-biomaterial interfacial interactions. Furthermore, bond-strength testing and measurement of marginal-sealing effectiveness (the two most commonly employed methodologies to determine "bonding effectiveness" in the laboratory) are evaluated upon their value and relevance in predicting clinical performance. A new dynamic methodology to test biomaterial-tooth bonds in a fatigue mode is introduced with a recently developed micro-rotary fatigue-testing device. Eventually, today's adhesives will be critically weighted upon their performance in diverse laboratory studies and clinical trials. Special attention has been given to the benefits/drawbacks of an etch&rinse versus a self-etch approach and the long-term performance of these adhesives. Correlating data gathered in the laboratory with clinical results clearly showed that laboratory research CAN predict clinical effectiveness. Although there is a tendency to simplify bonding procedures, the data presented confirm that conventional three-step etch&rinse adhesives still perform most favorably and are most reliable in the long-term. Nevertheless, a self-etch approach may have the best future perspective. Clinically, when adhesives no longer require an "etch&rinse" step, the application time, and probably more importantly, the technique-sensitivity are substantially reduced. Especially "mild," two-step self-etch adhesives that bond through a combined micromechanical and chemical interaction with tooth tissue closely approach conventional three-step systems in bonding performance.

Two-year clinical effectiveness of a resin-modified glass-ionomer adhesive.

PURPOSE: To evaluate the clinical effectiveness of a resin-modified glass-ionomer adhesive FujiBond LC (GC) in non-carious Class V cervical lesions. METHODS: 28 patients and 52 abrasion-erosion lesions were restored using FujiBond LC and a microfilled resin composite in a cavity design with the adjacent enamel margins beveled. Clinical parameters as retention, marginal integrity, clinical microleakage, caries recurrence, esthetics, gingival response, tooth vitality and post-operative sensitivity were evaluated at 6 months, 1 and 2 years. RESULTS: A 100% retention rate was recorded after 2 years of clinical service. However, only 15% of the restorations showed a perfect marginal adaptation. All marginal defects were small, either located at the incisal or at the cervical margin. The percentage of small marginal defects was obviously higher at the incisal enamel margin than at the cervical dentin margin. At the 2-year recall, half of the restorations exhibited a superficial, localized discoloration at the restoration margin, however none of the restorations showed deep, generalized discoloration. Remaining criteria of clinical effectiveness were rated as excellent.

Microtensile bond strengths of one- and two-step self-etch adhesives to bur-cut enamel and dentin.

PURPOSE: To evaluate the bonding effectiveness of one- and two-step self-etch adhesives in comparison with a total-etch approach. METHODS: From 55 non-carious human third molars, mid-coronal dentin and enamel bur-cut surfaces were prepared. The bonding surfaces were treated strictly following the manufacturers' instructions with three one-step self-etch (all-in-one) adhesives, AQ bond, Reactmer and Xeno CF Bond; two two-step self-etch adhesives, experimental ABF and Clearfil SE Bond, one two-step total-etch adhesive, Prime & Bond NT, and one three-step total-etch adhesive, OptiBond FL. Composite built-ups were made using Z100. After storage overnight in 37 degrees C water, the bonded specimens were sectioned into rectangular slabs of approximately 2x2 mm width and 9 mm length. They were then trimmed into a round cross-sectional shape resulting in an interface area of approximately 1 mm2, and subsequently subjected to microtensile bond strength (microTBS) testing with a cross-head speed of 1 mm/minute. Differences in microTBS were determined for enamel and dentin using the Kruskal-Wallis test at P < 0.05. RESULTS: The microTBS to enamel varied from 10.3 MPa for the one-step self-etch adhesive AQ bond to 49.5 MPa for the total-etch adhesive Prime & Bond NT. The microTBS to dentin varied from 15.5 MPa for the one-step self-etch adhesive Reactmer to 59.6 for the three-step total-etch adhesive OptiBond FL. The microTBS of the total-etch adhesives to enamel was significantly higher than that of the one-step self-etch adhesives. Comparing the dentin microTBS, only OptiBond FL performed significantly better than the one-step self-etch adhesives. Specimen failure during preparation occurred with each one-step adhesive, but more frequently when bonding to enamel than to dentin. Most one-step self-etch adhesives failed predominantly adhesively between the tooth substrate and the bonding layer in contrast to the two- and three-step adhesives that revealed generally more mixed adhesive-cohesive failures.

Micro-tensile bond strength of two adhesives to Erbium:YAG-lased vs. bur-cut enamel and dentin.

The purpose of the study was to assess the hypotheses that laser irradiation is equally effective for bonding as traditional acid-etch procedures, and that tooth substrate prepared either by Erbium:YAG laser or diamond bur is equally receptive to adhesive procedures. Buccal/oral enamel and mid-coronal dentin were laser-irradiated using an Erbium:YAG laser. A total-etch adhesive (OptiBond FL) applied with and without prior acid-etching and a self-etch adhesive (Clearfil SE Bond) were employed to bond the composite. The micro-tensile bond strength (microTBS) was determined after 24 h of storage in water. Failure patterns were analysed using a stereo-microscope, and samples were processed for Field-emission Scanning Electron Microscopy (Fe-SEM) evaluation. Unbonded, lased enamel and dentin surfaces were evaluated using Fe-SEM as well. The total-etch adhesive bonded significantly less effectively to lased than to bur-cut enamel/dentin. Laser 'conditioning' was clearly less effective than acid-etching. Moreover, acid etching lased enamel and dentin significantly improved the microTBS of OptiBond FL. The self-etch adhesive performed equally to lased as to bur-cut enamel, but significantly less effectively to lased than to bur-cut dentin. It is concluded that cavities prepared by laser appear less receptive to adhesive procedures than conventional bur-cut cavities.