In vitro evaluation of marginal and internal adaptation after occlusal stressing of indirect class II composite restorations with different resinous bases and interface treatments. "Post-fatigue adaptation of indirect composite restorations”

The present study evaluated the influence of different composite bases and surface treatments on marginal and internal adaptation of class II indirect composite restorations, after simulated occlusal loading. Thirty-two class II inlay cavities were prepared on human third molars, with margins located in cementum. A 1-mm composite base extending up to the cervical margins was applied on all dentin surfaces in the experimental groups; impressions were made and composite inlays fabricated. The following experimental conditions were tested: no liner (control group), flowable composite treated with soft air abrasion (experiment 1), flowable composite sandblasted (experiment 2) and restorative composite sandblasted (experiment 3). All specimens were submitted to 1,000,000 cycles with a 100-N eccentric load. Tooth-restoration margins were analysed semi-quantitatively by scanning electron microscopy before and after loading; internal adaptation was also evaluated after test completion. The percentage of perfect adaptation in enamel was 79.5% to 92.7% before loading and 73.3% to 81.9% after loading. Perfect adaptation to dentin was reduced before loading (54.8% to 77.6%) and after loading (41.9% to 63%), but no difference was found among groups for pre- and post-loading conditions. No debonding occurred between the base and composite luting. A significant, negative influence of cyclic loading was observed. The results of the present study support the use of flowable or restorative composites as base/liner underneath large class II restorations. Soft air abrasion represents a potential alternative to airborne particle abrasion for treating cavities before cementation. The application of a composite base underneath indirect composite restorations represents a feasible non-invasive alternative to surgical crown lengthening to relocate cavity margins from an intra-crevicular to supra-gingival positio

Light polymerization during cavity filling: influence of total energy density on shrinkage and marginal adaptation

The aim of the study was to evaluate the marginal adaptation and shrinkage stress development of a micro hybrid restorative composite as a function of energy density. Linear displacement and shrinkage forces were measured with custom-made devices for energies of 4,000, 8,000, 16,000 and 32,000mJ/cm2 at a constant power density of 800mW/cm2. Marginal adaptation of composite restorations cured with the same energy density was evaluated before and after mechanical loading with 300,000 cycles at 70N. The group "4,000mJ/cm2” showed the lowest shrinkage force [2.9(0.2)kg] and linear displacement [23.5(0.7)μm] but led to the worst marginal adaptation after loading [46.4(23.5)%CM] probably due to under-curing. When the maximum energy of 32,000mJ/cm2 was applied, a slight increase in shrinkage forces [3.6(0.2)kg and 29.2(0.8)μm], and a slight decrease in marginal adaptation after loading [75.4(11.5)%CM] were observed, but these changes were not significantly different in comparison to groups cured with energies of 8,000 and 16,000mJ/cm2. For the resin composite tested in this study, no differences in marginal adaptation could be detected above the energy threshold of 8,000mJ/cm2

Post-orthodontic restorative approach for young patients with missing anterior teeth: no-prep and ultraconservative techniques

Aim The early loss of permanent teeth following trauma or congenital aplasia may be corrected in young patients by orthodontics and prosthetic-implant means. The aim of the present clinical review is to show how modern restorative options, such as enamel and gingival recontouring, bleaching and composite resin bonding, may improve the final clinical result after orthodontic space closure. Materials and methods The most common problems following orthodontically transposed teeth are unusual function, shape, dimension and color or deficient periodontal integration as a problematic long term maintenance of prosthetically replaced missing teeth, using or not implant supported restorations. This article presents clinical outcomes summarizing the benefists and positive impact of direct composite application to improve esthetics and function following orthodontic space closure. Conclusion There are different decisional levels for the treatment of young patients with missing anterior teeth which should be carefully weighted during treatment planning to satisfy demands regarding tissue conservation, function and esthetics and offer patients the best available solution

No-prep interceptive rehabilitation - of tooth wear using a free-hand technique driven by a functional wax-up

Excessive abrasion (attrition) and erosion are two common conditions affecting dental hard tissue and occur in an increasing number of patients.1, 2 Both can be considered growing challenges in dentistry, because with such patients, especially in cases of severe parafunction, the etiology can rarely be successfully and permanently eliminated.3–5Therefore, continuous monitoring to control related pathologies is required

Traitement interceptif de l'usure dentaire par méthode directe

Un nombre croissant de patients présentent des lésions dues à une abrasion excessive (attrition) et à une érosion dentaire, deux phénomènes courants affectant les tissus durs de la dent [1,2]. Ils posent en outre une vraie problématique en dentisterie, quand on sait que leur étiologie ne peut être que très rarement éliminée de façon efficace et durable et ce, particulièrement dans les cas de parafonctions sévères [3-5]. Un suivi régulier s'avère par conséquent nécessaire pour dépister les pathologies induites par ces phénomènes

Shading concepts and layering techniques to master direct anterior composite restorations: an update

Creating perfect direct composite restorations has been for long time a strict challenge due to many materials' limitations impacting either shade integration or surface quality, and possibly colour stability. Next to technological drawbacks, a certain complexity and lack of predictability in clinical application was inherent to the technique and made it elitist for a long time. Shading and layering concepts then progressively evolved from a simplistic, non histo-anatomical, bilaminar technique to a multi-layering approach (3 to 4 or more layers), following the Vita Classic™ system. One of the most achieved concepts is polychromatic layering which makes use of a variable number of layers (basically VITA™ or non-VITA™ opacious dentin, chromatic enamel and translucent/opalescent enamel), driven by the natural tooth optical composition. In parallel with this evolution, a simplified, non-VITA shading system was developed with a reduced number of layers (basically dentin &enamel layer, plus effect shades if required) known as the natural layering concept, aiming to the same optimal esthetic integration and natural colour reproduction/emulation. The latest improvements appear all driven by the same view of improved reliability and clinical simplificatio

Evidence-based concepts and procedures for bonded inlays and onlays. Part III. A case series with long-term clinical results and follow-up

This third article in this series (Part III) aims to present new clinical results and long-term follow-up of resin composite inlays and onlays using the modern clinical concepts presented in the Part I and Part II articles. These revised protocols have contributed to eliminating the most frequent difficulties related to the preparation, isolation, impression taking, and cementation of tooth-colored inlays and onlays. This clinical report presents a series of 25 cases of indirect or semidirect inlays and onlays (intra- and extraoral techniques) made of microhybrid and nanohybrid composites with 6- to 21-year follow-ups. The restoration performance was assessed through clinical examination, intraoral radiographs, and clinical photographs. The overall clinical assessment aimed to confirm the absence (success) or presence (failure) of decay or restoration fracture, while the restoration quality was judged on intraoral photographs. The restoration status with regard to margins, anatomy, and color was assessed using three quality scores (A = ideal, B = satisfactory, C = insufficient). Descriptive statistics were used to evaluate the possible impact of composite structure (microhybrid or nanohybrid) or observation time on restoration quality. Over this medium- to long-term observation period, no clinical failure was reported. Only a few restorations (mainly those made of conventional inhomogeneous nanohybrid) presented discrete marginal discoloration (n = 4) or occlusal anatomy change due to wear (n = 7). This first clinical survey with long-term follow-up supports the application of the aforementioned clinical concepts, which thus far have only been validated by in vitro studies