The multi-luting concept: a new approach to facilitate the adhesive luting of multiple indirect restorations.

Bonded indirect restorations can be difficult to lute in an accurate position due to the lack of preparation geometry. Furthermore, while the use of a rubberdam has been proven to be the best technique for providing the most efficient conditions for adhesive luting, its use often requires the use of secondary clamps, which do not allow the operator to lute more than two prosthetic pieces at the same time. The multi-luting concept is a pragmatic approach that of- fers the possibility to deliver several, if not all restorations, to be bonded at the same time, thus ensuring their correct positioning.

Therapeutic strategy for cracked teeth.

The management of cracked teeth represents a difficulty because their diagnosis is complex and there is no consensus concerning their treatment. The present article explains this pathology within enamel and dentin and also focuses on the clinical consequences of crack development in dental tissue. As cracks have both biologic and mechanical implications, a complete review of the literature on the subject has enabled the development of a comprehensive diagnostic approach to identify cracked teeth and optimize their management. The elements of diagnosis are the bite test, transillumination, the pulp sensitivity test, the periodontal test, radiologic examinations, removal of existing restorations, and the use of quantitative light-induced fluorescence. Finally, the management of biologic and mechanical imperatives relating to the treatment of cracked teeth has allowed the proposal of a reliable and reproducible therapeutic strategy based on two pillars: the arrest of bacterial infiltration using immediate dentin sealing, and the limitation of crack propagation using relative cuspal coverage. In this article, the proposed clinical protocol is explained through the use of a decision map and is illustrated by a clinical case example.

[The perenity of the indirect bonded restorations : the «no-finishing concept¼]. / Pérennité des restaurations indirectes collées : « the no-finishing concept ¼.

Over the past 30 years, the development of adhesive techniques has reduced the biological cost of bonded indirect restorations (in/onlays and veneers). However, the procedures for bonding to dental tissue are still more demanding than those for conventional cemented prostheses. One of the keys to the durability of indirect adhesive restorations is their ability to prevent bacterial plaque from adhering to their surface. With this in mind, this article describes a clinical protocol for obtaining the smoothest possible prosthetic margins, without resorting to conventional finishing and polishing techniques, which are tedious and time-consuming.

Seeing is believing? When scanning electron microscopy (SEM) meets clinical dentistry: The replica technique.

In restorative dentistry, the in situ replication of intra-oral situations, is based on a non-invasive and non-destructive scanning electron microscopy (SEM) evaluation method. The technique is suitable for investigation restorative materials and dental hard- and soft-tissues, and its interfaces. Surface characteristics, integrity of interfaces (margins), or fracture analysis (chipping, cracks, etc.) with reliable resolution and under high magnification (from ×50 to ×5,000). Overall the current study aims to share detailed and reproducible information about the replica technique. Specific goals are: (a) to describe detailed each step involved in producing a replica of an intra-oral situation, (b) to validate an integrated workflow based on a rational sequence from visual examination, to macrophotography and SEM analysis using the replica technique; (c) to present three clinical cases documented using the technique. A compilation of three clinical situations/cases were analyzed here by means the replica technique showing a wide range of possibilities that can be reached and explored with the described technique. This guidance document will contribute to a more accurate use of the replica technique and help researchers and clinicians to understand and identify issues related to restorative procedures under high magnification.

The secrets of isolation in the cervical area / Isolation et lésions cervicales. Stratégie et solutions cliniques

It is often presumed that, since its introduction in 1864, the use of rubber dam in multiple dental procedures has increased. However, its use is not as widespread as one might expect. There still seem to be many obstacles that prevent clinicians from adopting it as a standard of care. Furthermore, it appears very difficult to scientifically prove the impact of its use on the final outcome of a given procedure. The fundamental idea of isolating the operatory field and preventing contamination is simple; the practical execution of it is more demanding. In this article, the authors not only focus on the essential criteria for predictable isolation, they also present an isolation strategy that can be translated into a step-by-step procedure. It is suggested that by adopting this strategy, clinicians can eliminate the most commonly experienced obstacles and optimize the full potential of isolation, even in extremely difficult clinical situations.

Precision and security in restorative dentistry: the synergy of isolation and magnification.

It is often presumed that, since its introduction in 1864, the use of rubber dam in multiple dental procedures has increased. However, its use is not as widespread as one might expect. There still seem to be many obstacles that prevent clinicians from adopting it as a standard of care. Furthermore, it appears very difficult to scientifically prove the impact of its use on the final outcome of a given procedure. The fundamental idea of isolating the operatory field and preventing contamination is simple; the practical execution of it is more demanding. In this article, the authors not only focus on the essential criteria for predictable isolation, they also present an isolation strategy that can be translated into a step-by-step procedure. It is suggested that by adopting this strategy, clinicians can eliminate the most commonly experienced obstacles and optimize the full potential of isolation, even in extremely difficult clinical situations.

Full-mouth adhesive rehabilitation in a case of amelogenesis imperfecta: a 5-year follow-up case report.

Amelogenesis imperfecta (AI) is a hereditary disorder caused by mutations of genes primarily involved in the enamel formation. Several different types of AI have been identified, based on the phenotype and on the mode of inheritance. Regardless of the type, the dental treatment tends to be the same, favoring the complete removal of the compromised enamel late in the patient's life. With the new dentistry guidelines that orient clinicians towards minimal invasiveness, it should be mandatory to intercept patients affected by AI earlier, not only to protect the dentition from further degradation but also to help patients improve their self-esteem. This article examines the restorative dentistry performed on a 24-year-old Caucasian female suffering from the hypoplastic type of AI, using only adhesive procedures. Due to the complex needs of the patient, an interdisciplinary approach was followed, involving orthodontics, periodontics, and restorative dentistry. A full-mouth adhesive rehabilitation was achieved by means of direct composite restorations, veneer/onlays and facial/palatal veneers. No elective endodontic therapy was necessary for restorative purposes. The esthetics, mechanics, and biological success were achieved and maintained. The bond to the enamel did not show signs of degradation (eg, discoloration or infiltration) even after 5 years of function. This is encouraging as it shows that adhesive techniques may be a reliable approach even in the presence of a compromised enamel layer.

Influence of curing mode with a LED unit on polymerization contraction kinetics and degree of conversion of dental resin-based materials.

PURPOSE: The purpose of this study was to evaluate the influence of photopolymerization mode with a light emitting diode (LED) lamp on the curing contraction kinetics and degree of conversion of 3 resin-based restorative materials. METHODS: The curing contraction kinetics of Admira (ADM), Filtek P60 (P60), and Filtek Flow (FLO) were measured by the glass slide method. The materials were exposed to light from a 1,000 mW/cm-(2) power LED lamp (Elipar Freelight 2) in 3 modes: 2 continuous modes of 20 and 40 seconds (C20 and C40), and 1 exponential mode (E20; 5 seconds of exponential power increase followed by 15 seconds of maximum intensity). The degree of conversion (DC) was measured for each of the materials, and each of the modes by Fourier transformed infra-red spectrometry. RESULTS: P60 had the significantly lowest final contraction and FLO the highest among all light exposure modes. The C20 and C40 modes did not produce any difference in contraction or degree of conversion. The E20 mode led to a significant slowing of contraction speed combined with greater final contraction. CONCLUSIONS: Use of a LED lamp (1,000 mW/cm2) in continuous mode reduces the exposure time by half for identical curing shrinkage and degree of conversion.

Water sorption and water solubility of current luting cements: an in vitro study.

OBJECTIVE: To evaluate the water-sorption characteristics and the solubility behavior of 4 luting cements-2 composite resins (CRs), a polyacid-modified composite resin (PMCR), and a resin-modified glass-ionomer cement (RMGIC)-according to the ISO 4049 specifications. METHOD AND MATERIALS: Five disks (15 x 1 mm) of each material (Variolink II [CR1; Vivadent], Panavia F [CR2; Kuraray], Resinomer [PMCR; Bisco], and Fuji Plus [RMGIC; GC]) were prepared according to the manufacturers' instructions. Specimens were first desiccated until a consistent mass was obtained. Specimens were immersed for 7 days in distilled water and immediately weighed after this period. Then the disks were post-desiccated and weighed every day for 35 days. The water sorption and solubility of each specimen were calculated according to the change in its weight as observed before and after immersion and desiccation periods. RESULTS: Fuji Plus exhibited the overall higher values of water sorption and solubility (P < .001). Of the 3 resin-based luting cements, Resinomer demonstrated significantly higher water sorption and solubility (P < .001), whereas Variolink II and Panavia F showed low values and were not significantly different (P = .2). CONCLUSIONS: Behavior of resin-based materials in water varies according to the composition characteristics. In particular, the high portion of hydrophilic chemical species, as well as the filler characteristics, provoke very high water sorption and solubility values. In this way, and within the limitations of this in vitro study, composite resin luting cements appear to be more suitable than compomers and resin-modified glass-ionomer cements to meet longevity requirements.

Microleakage and polymerization shrinkage of various polymer restorative materials.

PURPOSE: The aim of this in vitro study was to evaluate the polymerization shrinkage and the microleakage of direct resin-based restorative materials commonly used in pediatric dentistry. METHODS: Standardized Class V cavities overlapping the cementoenamel junction were prepared on the buccal and the lingual surfaces of 40 extracted human mandibular third molars (36 specimens, 4 controls). The cavities were restored with 4 different materials: a packable resin composite (Filtek P60), a compomer (Compoglass F), an ormocer (Admira) and their associated bonding agents (Scotchbond 1, Excite, and Admira Bond, respectively), and a resin-modified glass ionomer (Fuji II LC). The teeth were then immersed in methylene blue solution for 48 hours. Dye penetration was evaluated for all materials, which were analyzed using a multivariate model (alpha=0.05): influence of microleakage score, margin location (enamel/cementum), and preparation location (buccal/lingual). Multivariate analysis was performed using a polychotomous logistic regression. Polymerization shrinkage was evaluated by the disk deflective method. The percentage of polymerization shrinkage (N=3) was evaluated by ANOVA and Tukey test. RESULTS: Regarding polymerization shrinkage, the P60 demonstrated the lowest value, followed by ADM and COF, whereas FLC presented the highest shrinkage-strain (P<.0001). The preparation location had no significant effect on dye penetration (P=.86). Margin location (enamel or cementum) had a significant effect on microleakage (odds ratio [OR]=24.61). Significant differences in the microleakage patterns and scores were also observed between the 4 restorative materials. Admira exhibited the lowest overall microleakage. In comparing Filtek P60, Compoglass F, and Fuji II LC to Admira, P60 showed significantly less microleakage (OR=1.30) than Fuji II LC (OR=1.47), whereas Compoglass F demonstrated the greatest significant overall microleakage (OR=3.15). CONCLUSION: Within the experimental conditions of this in vitro study, the microleakage was significantly lower at the enamel margins than at the cementum margins for the four restorative materials tested. The ormocer and the packable resin composite exhibited the best sealing ability, as well as the lowest polymerization shrinkage. It could not be demonstrated in this study, however, that the higher the polymerization shrinkage was, the lower the marginal sealing ability was.

Influence of initial water content on the subsequent water sorption and solubility behavior in restorative polymers.

PURPOSE: To evaluate the water sorption characteristics and solubility behavior of two resin-based composites, an ormocer, a compomer and a resin-modified glass-ionomer, according to ISO 4049 specifications and also without the initial desiccation cycle. METHODS: After polymerization, five disks (15 x 1 mm) of each material [Filtek P60 (P60), Solitaire 2 (SOL2), Admira (ADM), Compoglass F (COF) and Fuji II LC (FLC)] were desiccated until a constant mass (ml) was obtained. They were immersed in distilled water for 7 days and immediately weighed after that period (mass m2). Then disks were again desiccated and weighed every day for 35 days (mass m3). Sorption and solubility values were deduced from these different measures. Without initial desiccation mass m1 was obtained just after polymerization. RESULTS: Without initial desiccation, all the materials absorbed less water and solubility was 1.5 to 8 times greater than in standard experiment. For the two protocols, water sorption and solubility were significantly greater in FLC, and ADM showed the least weight loss of all the materials tested.

In vitro evaluation of microleakage of indirect composite inlays cemented with four luting agents.

STATEMENT OF PROBLEM: Microleakage around dental restorations is implicated in the occurrence of secondary carious lesions, adverse pulpal response, and reduced restoration longevity. PURPOSE: The aim of this in vitro study was to evaluate the microleakage of indirect resin composite inlays cemented with 4 luting agents. MATERIAL AND METHODS: Standardized Class V inlay preparations overlapping the cemento-enamel junction were prepared on the buccal and lingual surfaces of 40 extracted human mandibular third molars. Eighty postpolymerized, heat-treated resin composite inlays (Targis, 72 specimens, 8 controls) were processed in stone replicas and cemented into the preparations using 4 luting agents (n = 18 + 2 controls for each cement group): a resin composite used with a bonding agent (Variolink II/Excite), a resin composite used with a self-etching primer, but without bonding agent (Panavia F/ED Primer), a modified resin composite used with a bonding agent (Resinomer/One Step), and a resin-modified glass-ionomer cement (Fuji Plus). Thirty-six inlays (n = 9 + 1 control) were subjected to thermal cycling (2000 cycles, 5 degrees C/55 degrees C), whereas the other 36 were not. All the teeth were then immersed in 1% methylene blue dye solution for 48 hours. Microleakage score, margin location (enamel/cementum), thermal cycling history, and preparation location (buccal/lingual) were analyzed using a multivariate model (alpha = .05). Multivariate analysis was performed using a polychotomous logistic regression. RESULTS: The preparation location had no significant effect on dye penetration. The margin location (enamel or cementum) and the thermal cycling had a significant effect on microleakage (odds ratios [ORs] = 17.6 and 8.04, respectively). In comparing the 3 resin-based luting agents (Variolink II, Panavia F, and Resinomer) to Fuji Plus, Panavia F exhibited the lowest significant overall microleakage (OR = 0.09), followed by Variolink II (significant OR equal to 0.43), whereas Resinomer demonstrated the greatest significant overall microleakage (OR = 1.35). CONCLUSION: Within the experimental conditions of this in vitro study, thermal cycling significantly increased microleakage (OR = 8.04). The overall microleakage at the enamel margins was significantly lower than the overall microleakage at the cementum margins for the 4 luting agents tested (OR = 17.6).

Importance of water sorption and solubility studies for couple bonding agent--resin-based filling material.

This study investigated the water sorption and solubility of two light-cured resin composites (Filtek P60 and Solitaire 2), one compomer (Compoglass F), one ormocer (Admira) and the associated bonding agents (Scotchbond 1 [Scotchbond 1 = Scotchbond Single Bond in USA], Gluma One Bond, Excite and Admira Bond, respectively) and of a RMGIC (Fuji II LC). Five disks of each product type were subjected to water sorption and solubility tests based on ISO 4049 requirements. The data were subjected to Kruskal-Wallis and non-parametric multiple-comparison tests using ranked sums at 95% confidence interval. Fuji II LC showed the highest water sorption (167.5 microg/mm(-3)). Fuji II LC and Compoglass F had higher solubility values (8.3 and 10.0 microg/mm(-3), respectively) than the other materials. Bonding agents have very high water sorption and solubility values (between 77.4 and 355.4 microg/mm(-3) and between 75.9 and 144.9 microg/mm(-3), respectively) compared to the restorative materials. Gluma One Bond and Admira Bond showed lower sorption and solubility than Excite and Scotchbond 1.