Luting of ceramic crowns with a self-adhesive cement: effect of contamination on marginal adaptation and fracture strength

Objectives: This study evaluated the percentages of continuous margins (%CM) and fracture strength (FS) of crowns made out from blocs of leucite-reinforced ceramic (IPS Empress CAD) and luted with a representative self-adhesive cement (RelyX Unicem) under four contaminating agents: saliva, water, blood, a haemostatic solution containing aluminium chloride (pH= 0.8) and a control group with no contamination. Study Design: %CM at both tooth-cement (TC) and cement-crown (CC) interfaces were determined before and after a fatigue test consisting of 600'000 chewing loads and 1'500 temperature cycles changing from 5º C to 50º C. Load to fracture was recorded on fatigued specimens. Kruskal-Wallis test was used to compare %CM and FS between the five groups with a level of confidence of 95%. Results: At the TC interface, no significant differences in marginal adaptation before loading could be detected between groups. After loading, a significant marginal degradation was observed in the group contaminated with aluminium chloride (52 ± 22 %CM) in respect to the other groups. No significant differences in %CM could be detected between the groups contaminated with saliva, water, blood and the control. At the CC interface, no significant differences in marginal adaptation were observed between the groups. The FS on loaded specimens was around 1637N, with no significant differences between groups as well. Conclusions: An adverse interaction of the highly acidic haemostatic agent with either dentin or the self-adhesive cement could explain the specimens' marginal degradation. The self-adhesive cement tested in this study was no sensitive to moisture contamination either with saliva, water or blood

The competition between enamel and dentin adhesion within a cavity: An in vitro evaluation of class V restorations

To gain more insight into the consequences of curing contraction within the tooth cavity, we assessed the margin behavior of 12 contemporary restorative systems in class V restorations with margins located on enamel and dentin after mechanical loading and water storage. Mixed class V cavities were prepared on extracted human molars and restored using five etch and rinse and seven self-etch adhesive systems with their corresponding composites. Marginal adaptation was evaluated by using a computer-assisted quantitative marginal analysis in a scanning electron microscope (SEM) on epoxy replicas before, after thermal and mechanical stressing and after 1year of water storage. The interactions of "testing conditions”, "adhesive-composite combination” and "tooth substrate” with "marginal adaptation” were evaluated by two-way ANOVA. Fatigue, stress and storage conditions had significant effects on the marginal adaptation. Only two groups (Optibond FL and G Bond) presented equal percentages of marginal adaptation on enamel and dentin; in the other groups, the rate of degradation was product dependent. All materials tested showed a distinct behavior on enamel and dentin. In addition to mechanical resistance and long-term stability, differences within materials also exist in their ability to simultaneously bond to enamel and denti

Morphology of the smear layer after the application of simplified self-etch adhesives on enamel and dentin surfaces created with different preparation methods

Mild self-etching adhesive systems modify and/or incorporate the smear layer into the resin-infiltrated demineralised dentin. Some factors such as type of bur and use of water spray might affect the thickness of the smear layer on substrates, enamel and dentin. Because of this, the present study evaluated the thickness of smear layers created by different finishing procedures, after the application of three simplified self-etching primers (Adper Prompt L-Pop and two experimental formulations) on enamel and dentin. After the application and removal of the primers' resinous component, the specimens were prepared for examination under a scanning electron microscope. Smear layers were thicker on enamel than on dentin, irrespective of the finishing methods used. Therefore, different thicknesses of smear layer on enamel/dentin might be an important factor to consider when evaluating the bonding efficacy of self-etching adhesives to both tooth substrate

Bulk filling of Class II cavities with a dual-cure composite: effect of curing mode and enamel etching on marginal adaptation

Objectives: This study attempted to find a simple adhesive restorative technique for class I and II cavities on posterior teeth. Study Design: The tested materials were a self-etching adhesive (Parabond, Coltène/Whaledent) and a dual-cure composite (Paracore, Coltène/Whaledent) used in bulk to restore the cavities. Class II MO cavities were performed and assigned to 4 groups depending on the orthophosphoric acid (H 3 PO 4 ) conditioning of enamel and polymerization method used (chemical or dual). Specimens were subjected to quantitative marginal analysis before and after thermo-mechanical loading. Results: Higher percentages of marginal adaptation at the total margin length, both before and after thermo-mechanical loading, were found in groups in which enamel was etched with phosphoric acid, without significant differences between the chemically and dual-cured modes. The restorations performance was similar on enamel and dentin, obtaining low results of adaptation on occlusal enamel in the groups without enamel etching, the lowest scores were on cervical dentin in the group with no ortophosphoric acid and self-cured. Conclusions: A dual-cure composite applied in bulk on acid etched enamel obtained acceptable marginal adaptation results, and may be an alternative technique for the restoration of class II cavities

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

In Vitro Assessment of Single-Retainer Tooth-Colored Adhesively Fixed Partial Dentures for Posterior Teeth

The purpose of this paper was to investigate, by means of marginal adaptation and fracture strength, three different types of single retainer posterior fixed partial dentures (FPDs) for the replacement of a missing premolar. Two-unit cantilever FPDs were fabricated from composite resin, feldspathic porcelain, and fiber-reinforced composite resin. After luting procedures and margin polishing, all specimens were subjected to a Scanning Electron Microscopic marginal evaluation both prior to and after thermomechanical loading with a custom made chewing simulator comprising both thermal and mechanical loads. The results indicated that the highest score of marginal adaptation, that is, the closest score to 100% of continuous margins, at the tooth-composite resin interface was attained by the feldspathic porcelain group (88.1% median), followed by the fiber-reinforced composite resin group (78.9% median). The worse results were observed in the composite resin group (58.05% median). Fracture strength was higher in feldspathic porcelain (196N median) when compared to resin composite (114.9 N median). All the fixed prostheses made of fiber-reinforced composite resin detached from the abutment teeth before fracturing, suggesting that the adhesive surface's retainer should be increased

Restaurations proximales type "slot" en composite direct et inlays CAO/FAO fabriqués au fauteuil : adaptation marginale

But: Quantifier l'adaptation marginale, dans l'émail non biseauté, des obturations de Classe II, type "slot", en composite directe, des inlays en céramique et en composite fabriqués à l'aide de la technologie CAO/FAO au fauteuil. Observer si les différentes techniques d'obturation ainsi que la procédure de mordançage de l'émail, à l'aide de l'acide phosphorique, avant l'application d'un système adhésif auto-mordançant, ont une influence sur l'adaptation marginale avant et après un test de fatigue thermo-mécanique. Matériel et méthode: Comparaison entre deux groupes (n=6) de composites directs, deux groupes d'inlays en céramique et deux groupes d'inlays en composite, avec et sans mordançage acide (acide phosphorique) de l'émail, au moment de l'application d'un système adhésif auto mordançant en deux étapes (self-etch). L'adaptation marginale de ces obturations a été évaluée avant et après contraintes thermique et mécanique. Les tests statistiques "Kruskal Wallis et Mann Whitney U" pour les comparaisons entre les groupes et "Wilcoxon Signed Rank Test" pour la détection de différences entre les valeurs initiales et terminales dans le même groupe, ont été utilisés. Résultats: Différences significatives (p<0.05) entre les groupes concernant l'adaptation marginale. Après contrainte, différences significatives entre les groupes sans et avec le mordançage acide (acide phosphorique) de l'émail. Conclusion: La contraction de polymérisation demeure une propriété critique des matériaux de restaurations en composite. L'adaptation marginale des restaurations indirectes Classe II (type "slot", sans biseau) fabriquées soit en composite, soit en céramique, était meilleure que celle des obturations en composite directe. L'application de l'acide phosphorique sur l'émail avant l'utilisation d'un système adhésif auto-mordançant n'a pas amélioré l'adaptation marginale

Quadrantenversogung mit glaskeramischen CAD/CAM-Inlays

Das Aufkommen von Systemen zur Schmeld- und Dentinadhäsion hat in den Letzten Jarhehnten die Zahnärztliche Tätigkeit stark verändert. Infolgedessen sind makromechanisch verankerte metallische Restaurationene in der modernen konservierenden Zahnheilkunde von geringerer Beeutung und weniger attraktiv für die Patienten, die sich unauffällig versorgte Zähne wünschen

Marginal adaptation of direct and CAD/CAM proximal slot restorations using a self-etching adhesive system

To compare the marginal adaptation of proximal slot restorations using direct composite, ceramic and composite CAD/CAM inlays as restorative procedure and a self-etching adhesive syste

Marginal integrity of resin composite restorations restored with PPD initiatorcontaining resin composite cured by QTH, monowave and polywave LED units

This study evaluated the infl uence of curing devices on marginal adaptation of cavities restored with self-etching adhesive containing CQ and PPD initiators and hybrid composite. Twenty-four class V (3 groups, n=8) with margins located on enamel and dentin were restored with Clearfi l S3 Bond and Clearfi l APX PLT, light-cured with a monowave LED, multiwave LED and halogen light-curing unit (LCU). Marginal adaptation was evaluated with SEM before/after thermo-mechanical loading (TML). On enamel, signifi cantly lower % continuous margins (74.5±12.6) were found in group cured by multiwave LED when compared to monowave LED (87.6±9.5) and halogen LCU (94.4±9.1). The presence of enamel and composite fractures was signifi cantly higher in the group light-cured with multiwave LED, probably due to an increased materials' friability resulted from an improved degree of cure. The clinician should aware that due to a distinct activation of both initiators, marginal quality may be infl uenced on the long-term