Compatibility of five self-etching adhesive systems with two resin luting cements.

PURPOSE: The aim of this study was to evaluate the compatibility between five self-etching bonding systems (SEBSs) and two resin luting cements (RLCs) assessed by use of an in vitro dentin shear bond test. MATERIALS AND METHODS: The selected RLCs were: Variolink II in a dual-cure mode and Multilink in a self-cure mode. The SEBSs combined with the RLCs were: two one-step SEBSs (One Up Bond F and Xeno III) and three two-step SEBSs (Clearfil SE Bond, Unifil Bond, and Xeno III primer coupled with Clearfil SE Bond bonding resin as an experimental combination). One hundred fifty human molars were divided into ten groups of fifteen samples each. The samples were tested in shear after seven days of storage at 100% RH and 37°C. After each test, the failure mode was recorded. RESULTS AND CONCLUSIONS: Significant differences in shear bond strength (SBS) were observed according to both the curing mode of the RLC and the adhesive. The one-step systems Xeno III and One Up Bond F revealed a total incompatibility when bonded with the chemical-curing RLC. Conversely, the two-step SEBSs were compatible with chemical and dual-curing RLC. Failure modes and shear values were in good agreement. A positive correlation was found between the pH of the tested adhesive solutions or resins and the SBS data

Surface treatments on quartz fiber post: influence on adhesion and flexural properties.

PURPOSE: To evaluate (1) the effect of various surface treatments to optimize post adhesion, and (2) if these surface treatments had any adverse effect on the overall mechanical and chemical properties of the posts. METHODS: Six experimental batches were set according to the nature of the surface treatments which were followed or not by post silanization. Post surface treatments were: control, chloroform (CHCl3) and sandblasting (sand) with Al2O3 50 microm. The silane (sil) used was Silane Coupling Agent Calibra. In all cases, a dual-cure bonding agent was applied Prime&Bond NT + Self Cure Activator. The Groups were: 1 (control), 2 (sil), 3 (CHCl3), 4 (CHCl3 + sil), 5 (sand), 6 (sand + sil). Following surface treatments, the posts were embedded in resin composite and the composite-post interfacial strength was investigated with a push-out test. Flexural and fatigue tests were performed to control the mechanical performances of the treated posts. Push-out data were analyzed using two-way ANOVA and Scheffé's multiple means comparisons test (alpha = 0.05). SEM observations revealed the topographical modifications induced by sandblasting and the solvent. RESULTS: Sandblasting or surface treatment with chloroform increased the bond strength (P < 0.001). The best values were obtained with the combination of sandblasting followed by post silanization. The flexural properties were not modified by the surface treatments (P = 0.072) and all the posts reached 3,000,000 cycles without breaking.

Regional odontodysplasia: expression of matrix metalloproteinases and their natural inhibitors.

Regional odontodysplasia is a localized disorder of tissues of dental origin that results in a ghost-like appearance of the affected teeth. We present a case with a study of gingival tissue around the follicle. The results show evidence of the role of the matrix metalloproteinases and their natural inhibitors by resident cells in this pathosis. An imbalance in the amounts of matrix metalloproteinases and their natural inhibitors is associated with the pathologic breakdown of the collagen.

Self-etching adhesives improve the shear bond strength of a resin-modified glass-ionomer cement to dentin.

PURPOSE: Despite the improvements of resin-modified glass-ionomer cements, the dentin bond strength of these materials remains inferior to that provided by "bonding system/composite" combinations and limits the clinical use of RMGIC. The objective of this in vitro study was to investigate the effect of new self-etching bonding systems on the adhesion to dentin of Fuji II LC. MATERIALS AND METHODS: Seven recent self-etching systems were studied (Clearfil SE Bond = CSE, Optibond Solo Plus Self-Etching Primer = OSP, One Up Bond F = OUP, Mac Bond II = MB2, Xeno III = XB3, ADPER Prompt-L-Pop = ADP, Unifil Bond = UB) and compared with Cavity Conditioner (C). After the bonding procedure, a resin-modified glass-ionomer cylinder (Fuji II LC) was bonded to the surface using a Teflon mold (diameter: 3 mm; height: 5 mm). The different specimens were tested in a shear bond mode (0.5 mm/min). Statistical analyses were performed with one-way ANOVA and Fischer PLSD test (p < 0.05). RESULTS: The one-way ANOVA revealed a significant influence of the surface treatment parameter (p < 0.0001). The lowest shear bond strength values were obtained with Cavity Conditioner. The highest values were obtained with MB2. The multiple comparisons revealed that ADP = OBP = XB3 = OUB = UB = CSE and that UB = CSE = MB2. CONCLUSION: The application of the 7 self-etching adhesives tested in this study improves the dentin shear bond strengths of Fuji II LC. This increase depended on the adhesive system and ranged from 50% for ADP up to 130% for MB2.

In vitro evaluation of different techniques of enamel preparation for pit and fissure sealing.

PURPOSE: To compare the penetration and the imperviousness of two pit and fissure sealants according to surface treatments involving different cleaning procedures with or without subsequent acid etching. MATERIALS AND METHODS: Two sealants were used: a resin-based sealant (Concise White Sealant) and a compomer-based material (Dyract Seal) coupled with an enamel-dentin bonding agent (Dyract Seal and Prime&Bond NT). Extracted molars (n = 120) were randomly divided into 12 groups: 4 control and 8 experimental groups that received different surface treatments. Pumice, alumina, or bicarbonate was used to clean the surfaces. Phosphoric acid or non-rinse conditioner was used as acid etching agents. After sealing, the Concise White Sealant groups were directly thermocycled for 1800 cycles, while the Dyract Seal groups were stored in water for one month before thermocycling. After apex sealing and varnish coating, the fillings were stained with silver nitrate and embedded. Three to 6 cross sections of 200 microm each were made per sample to assess both sealant penetration (% of the length of the fissure) and the imperviousness of the seal (scores method). RESULTS: Concise White Sealant achieves a better enamel sealing than Dyract Seal when the teeth are treated with air abrasion or air polishing followed by etching. Acid etching is essential for good sealing, whatever the material and cleaning technique tested. Only the combination of air abrasion and phosphoric acid etching yielded a leak-free joint. CONCLUSION: This study clearly shows that penetration and sealing are two different phenomena. Ideally, an efficient sealant must have a good sealing ability and a high rate of infiltration as well, but these two properties probably do not have the same clinical relevance. The imperviousness of the seal remains the most important requirement.

Immediate replacement of a maxillary central incisor associated with severe facial bone loss: use of Bio-Oss collagen--case report.

The loss and replacement of anterior maxillary teeth pose several challenges. Treatment must successfully address immediate tooth replacement, esthetics, patient comfort, and psychologic acceptance. The purpose of this case report is to present a prosthetic and surgical technique for immediate tooth replacement following extraction in an area of severe localized bone loss. Combined full- and partial-thickness flaps associated with the use of Bio-Oss collagen grafting material and a Bio-Gide membrane were used for alveolar ridge reconstruction. To improve the final esthetic result, a connective tissue graft was used to increase ridge volume and papillary height.

Influence of the number of sections on reliability of in vitro microleakage evaluations.

PURPOSE: To test how the number of sections affects the maximum depth of tracer penetration. MATERIALS AND METHODS: This study was simultaneously performed in three different centers. C-shaped Class V cavities were made on 60 human third molars. The cavities were located across the cementum-enamel junction. One restorative system was used: Scotchbond Multi-Purpose and Z100. After restoration, the samples were thermally cycled 3000 times, between 5 and 55 degrees C with a dwell time immersion of 10 seconds. Silver nitrate was used by two centers and basic fuchsin was used by the third. The teeth were longitudinally sectioned with a diamond saw: 5 sections per tooth provided 10 surfaces for evaluation. The penetration of the tracer was recorded on a scale from 0 to 3. The deepest leakage per restoration was identified for comparison with lesser measured values elsewhere in the tooth. The Spearman test was applied to evaluate the relationship between the reference and data from one, two and three sections (i.e. two, four and six measurements). The Kruskal-Wallis test was applied to compare the three centers. RESULTS: Whatever the study center, the Spearman correlation coefficient (r(s)) increased as a function of the number of sections (S) up to three: Center 1 (1S, 0.47; 2S, 0.68; 3S, 1.0), Center 2 (1S, 0.60; 2S, 0.99; 3S, 0.99), Center 3 (S1, 0.40; 2S, 0.73; 3S, 1.0). No statistically significant difference was found between the three study centers.

Bonding to dentin achieved by general practitioners.

The objectives of this study were (1) to investigate the effect of operator variability on the shear bond strength of adhesives to dentin and (2) to determine the effectiveness of education on bonding performance for different types of adhesives. Thirty general practitioners were recruited for a CE course by a regional mailing. They used bovine dentin as a substrate for bonding the adhesive system they routinely used in practice and two other materials (no previous experience). Each adhesive OptiBond FL, ScotchBond Multipurpose Plus, ScotchBond 1 and Clearfil SE was applied according to manufacturer's instructions and immediately tested using a shear bond strength test. Shear bond strengths between adhesives and dentin were compared before and after a 90 min lecture on bonding principles and materials. For dentists with and without previous experience with a material, there were no statistically significant differences seen before and after the lecture (paired t-tests, p < or = 0.05). However, in every case, the bond strengths after the lecture were higher than those before (range of improvement from 15 to 150%). For dentists with routine experience with a particular material, all materials were statistically equivalent after the lecture, although the OptiBond FL was the highest. For dentists who had no previous experience with a material, the ScotchBond 1 had lower bond strengths than the other materials after the lecture. There was a large range in the ability of dentists to manipulate adhesive systems correctly. However, if a dentist has sufficient experience and receives sufficient education, any of these materials can give reasonable results.

Shear bond strengths of self-adhesive luting resins fixing dentine to different restorative materials.

The purpose of this study was to assess the bond strengths of three self-adhesive resin cements (Rely X Unicem, Maxcem and Multilink Sprint) fixing dentine to four different restorative substrates (Ni-Cr alloy, E-Max glass-ceramic, Y-TZP Zirconia and Adoro micro-filled composite) and to compare their performances with those of two conventional dual-cured luting cements (Variolink II + Total-etch Excite DSC and Multilink Automix + Self-etching Primer A + B). Cylindric specimens (5 x 5 mm) were prepared with the four restorative materials for bonding to human dentine. Three surface treatments were performed depending on the restorative material: (i) Al2O3 50 microm sandblasting (Ni-Cr, Adoro), (ii) #800 SiC polishing (Zirconia, E-Max), (iii) hydrofluoric acid (HF)-etching (E-Max). Twenty-five groups (n = 10) were designed according to luting cements, restorative materials and surface pre-treatments. In some experimental groups, Variolink II and Multilink Automix were coupled with, respectively, a silane primer (Monobond S) and an alloy/zirconia primer (Multilink A/Z primer). Specimens were stored in distilled water at 37 degrees C for 24 h and then loaded in shear until failure. Variolink II and Multilink Automix showed the highest bond strengths, regardless of the restorative substrate, when used with dentine bonding systems and primers, while the weakest bonds were with Maxcem. The bond strength recorded with the two other self-adhesive cements depended on the nature of the restorative substrate. Increasing retention at the interfaces (i.e., HF ceramic etching) and using specific primers significantly improves the bond strength of luted restorative materials to dentine.

Demineralized dentin 3D porosity and pore size distribution using mercury porosimetry.

OBJECTIVES: The objectives of this study were to assess demineralized dentin porosity and quantify the different porous features distribution within the material using mercury intrusion porosimetry (MIP) technique. We compared hexamethyldisilazane (HMDS) drying and lyophilization (LYO) (freeze-drying) in sample preparation. METHODS: Fifty-six dentin discs were assigned into three groups. The control (CTR) group discs were superficially acid-etched (15s 37% H(3)PO(4)) to remove the smear layer and then freeze-dried whereas LYO and HMDS groups samples were first totally demineralized using EDTA 0.5M and then freeze-dried and HMDS-dried respectively. MIP was used to determine open porosity and pore size distribution of each pair of samples. Field emission scanning electron microscopy (FESEM) was used to illustrate the results. RESULTS: The results showed two types of pores corresponding either to tubules and micro-branches or to inter-fibrillar spaces created by demineralization. Global porosity varied from 59% (HMDS-dried samples) to 70% (freeze-dried samples). Lyophilization drying technique seems to lead to less shrinkage than HMDS drying. FESEM revealed that collagen fibers of demineralized lyophilized samples are less melted together than in the HMDS-dried samples. SIGNIFICANCE: Demineralized dentin porosity is a key parameter in dentin bonding that will influence the hybrid layer quality. Its characterization could be helpful to improve the monomers infiltration.

Adhesion of a quartz fibre post to a composite resin core: influence of bonding agents and their curing mode.

Fibre-reinforced composite posts are currently used to restore endodontically-treated teeth. Push-out tests were carried out to evaluate the performance of several bonding agents on the retention of an endodontic quartz fibre post to a composite resin core. Five bonding agents were investigated in both self-cure and light-cure modes. Ten experimental groups of 10 posts each were constituted as a function of curing mode and bonding agent. Specimens were mounted in a dedicated Teflon mould. This experimental set-up allowed the determination of true shear strength. One-way ANOVA and Student-Newman-Keuls tests were used for statistical analysis. The bonding strengths ranged from 23.4 MPa to 35.3 MPa. The best results were obtained with a light-cure self-etch bonding agent; in all cases photo-polymerisation led to statistically higher bonding strengths compared to chemical auto-polymerisation. Shear bond strength at the post-adhesive interface was also found to be significantly dependent on the nature of the bonding agent. AdheSe self-etch bonding agent was more effective than etch-and-rinse single-component bonding agents.

Influence of self-etching primer preapplication on the dentin-titanium shear bond strength mediated by a resin-modified glass-lonomer cement.

PURPOSE: The aims of this study were to evaluate the in vitro shear bond strength of the dentin-titanium interface mediated by Fuji Plus, a resin-modified glass-ionomer cement, applied in combination with several self-etching bonding systems, and to compare the values obtained with those of SuperBond, chosen as a reference luting agent. MATERIALS AND METHODS: The self-etching bonding systems used in combination with Fuji Plus were AdheSE, Xeno III, Clearfil SEBond, Unifil Bond, and an experimental self-etching bonding system comprising the sequential application of Xeno III and the bonding component of SE Bond. Two control groups were also tested: a negative control with Fuji Plus along with its conditioner (10% ferric chloride, 2% citric acid solution); and a positive control with the resin cement SuperBond. One hundred five human molars were used to prepare seven groups of fifteen samples each. The samples were tested in shear after 7-day storage at 100% relative humidity and 37 degrees C. RESULTS AND CONCLUSION: Three of the tested combinations of self-etching bonding systems with Fuji Plus significantly improved in comparison with the negative control group, from 9% to 44%. The self-etching bonding systems obtained using Fuji Plus in combination with Clearfil SEBond, Unifil Bond, and the experimental system were not different from those obtained with SuperBond.

[The various families of composite adhesives: presentation and experimentation]. / Les différentes familles de colles composites: présentation et expérimentation.

Today, manufacturers provide the orthodontist with a range of adhesive systems which is so wide that is often difficult for the orthodontist to make his choice between them. The adhesive systems fall into four categories: traditional hydrophobic bonding systems, hydrophilic bonding systems, self-etching bonding systems, resin-modified glass ionomer-cements. This article will attempt to examine the first three categories which correspond to those of the composite bonding systems. Following a presentation of bonding assembling and of the required specification of the bonding systems used in orthodontic practice, the three composite bonding systems will be examined along with their advantages/disadvantages before a closing description of the corresponding clinical protocol to be followed. Whenever one of our laboratory experiments enables us to provide experimental evidence, a presentation is made within the related chapters.

In vitro push-out strength of seven luting agents to dentin.

PURPOSE: New luting agents, described as resin-modified glass-ionomer cements and compomers, have been developed during the last decade to improve the retention of cemented restorations. The aims of this study were to (1) compare the push-out strength of these new luting materials against both conventional cements and bonding luting agents, and (2) evaluate the influence of dentin surface treatment on both glass-ionomer cement and 4-META adhesive resin push-out strength. MATERIALS AND METHODS: Conical standardized cavities were drilled in the center of coronal dentin disks. Ninety sandblasted Ni-Cr inlays, divided into nine batches, were luted into the cavities according to the surface treatment and the nature of the following luting agents: zinc phosphate cement, zinc polycarboxylate cement, type 1 glass-ionomer +/- polyacrylic acid, resin-modified glass-ionomer, polyacid-modified composite resin, filled bis-GMA phosphate ester resin, and 4-META adhesive resin +/- application of activated monomer. Each specimen was placed in a holding device, and a steel rod was used to apply a force on the inlay until rupture occurred. The push-out strength was calculated, and the failure mode was controlled. RESULTS: There were significant differences between some of the groups. The highest push-out strength was achieved by the 4-META adhesive resin after application of activated monomer. The lowest value was attained with zinc phosphate and polycarboxylate cements. CONCLUSION: Both resin-modified glass-ionomer and polyacid-modified composite resin luting materials exhibited a push-out strength similar to resin-based materials. Specific dentin surface treatments significantly enhanced the push-out strengths of glass-ionomer cement and 4-META adhesive resin.