Bond strength of resin cement to ceramic with simplified primers and pretreatment solutions.

Manufacturers have recently introduced surface primers and pretreatment solutions that reportedly simplify the bonding process of resin cements to ceramics through various combinations of etchant and coupling agents. This study evaluated the shear bond strength (SBS) of a resin cement to a lithium disilicate glass-ceramic material pretreated with various new surface treatment solutions and compared the results to those of a control group prepared with the traditional application of hydrofluoric acid (HF) and silane. Resin cement was bonded to pretreated glass-ceramic surfaces, and specimens were tested for SBS after 24 hours of storage in water. Traditional surface treatment of lithium disilicate glass ceramic with HF and silane resulted in a significantly greater mean SBS than did simplified primer solutions. There were no statistically significant differences among the simplified pretreatment groups. In the control group, the majority of failures were due to mixed adhesive-cohesive fracture, while in the simplified treatment groups the failure mode was usually adhesive, suggesting a weaker interface.

Thermal oxidation and hydrofluoric acid treatment on the sandblasted implant surface: A histologic histomorphometric and biomechanical study.

OBJECTIVES: This study aimed to analyze and compare the topographical, chemical, and osseointegration characteristics of a sandblasted acid-etched surface (SLA group), a sandblasted thermally oxidized surface (SO group), and a surface chemically modified by hydrofluoric (HF) acid (SOF group). MATERIALS AND METHODS: Following the preparation and characterization of the relevant surfaces, 90 implants (30 for each group) were placed on the pelvic bone of six sheep. Resonance frequency analysis (RFA), insertion (ITV), removal torque value (RTV), and histomorphometric analyses (BIC%) were performed after three and 8 weeks of healing. The results were analyzed by nonparametric tests (p < 0.05). RESULTS: The roughness value (Ra) in the SOF group was significantly lower than the SLA and the SO group (p = 0.136, p < 0.001, respectively). This resulted in a substantially inferior ITV 14.83 N/cm (SD: 4.04) than those achieved in the SLA and SO groups (19.50 (SD: 6.07) and 20.17 N/cm (SD: 8.95), respectively; p = 0.001). A statistically significant change in the RFA from the baseline (47.36 ISQ, SD: 6.93) to the 3rd week (62.56 ISQ, SD: 5.29) was observed in the SOF group only (p = 0.008). The highest postplacement RFA and RTV values were measured from the SLA group (61.11 ISQ, SD: 7.51 and 78.22 N/cm, SD: 28.73). The early-term (3rd week) BIC% was highest in the SO group (39.93%, SD: 16.14). After 8 weeks, the differences in BIC% values were statistically not significant. CONCLUSIONS: Adjunct HF acid application on the thermally oxidized surface did not provide an additional benefit compared to the sandblasted and acid-etched surface (SLA group).

Fatigue failure load of feldspathic ceramic crowns after hydrofluoric acid etching at different concentrations.

STATEMENT OF PROBLEM: Hydrofluoric acid etching modifies the cementation surface of ceramic restorations, which is the same surface where failure is initiated. Information regarding the influence of hydrofluoric acid etching on the cyclic loads to failure of ceramic crowns is lacking. PURPOSE: The purpose of this in vitro study was to evaluate the influence of different hydrofluoric acid concentrations on the fatigue failure loads of feldspathic ceramic crowns. MATERIAL AND METHODS: Eighty feldspathic ceramic crowns were cemented with resin cement to identical simplified complete crown preparations machined in a dentin-like polymer. The preparations were etched with 10% hydrofluoric acid for 60 seconds and received a primer coating. Before cementation, the intaglio of the ceramic crowns was treated with 1 of 4 surface conditionings (n=20): nonconditioned (control, CTRL), or etched for 60 seconds with different hydrofluoric acid concentrations: 1% (HF1), 5% (HF5), and 10% (HF10). A silane coupling agent was applied on this surface of all crowns, which were cemented to the preparations. Each crown was cyclically loaded in water with a G10 epoxy-glass piston positioned in the center of the occlusal surface. Fatigue failure loads of ceramic crowns were obtained by the staircase approach after 500000 cycles at 20 Hz. Mean failure loads were analyzed by 1-way ANOVA and the Tukey test (α=.05). RESULTS: Mean failure loads of groups CTRL (245.0 ±15.1 N), HF1 (242.5 ±24.7 N), and HF10 (255.7 ±53.8 N) were statistically similar (P>.05), while that of the HF5 group (216.7 ±22.5 N) was significantly lower (P<.05). CONCLUSIONS: HF5 acid had a negative effect on the fatigue loads of the tested feldspathic ceramic crowns, while HF1 and HF10 acids did not change the fatigue resistance.

Effects of different etching methods and bonding procedures on shear bond strength of orthodontic metal brackets applied to different CAD/CAM ceramic materials.

OBJECTIVE: To investigate the shear bond strength (SBS) of orthodontic metal brackets applied to different types of ceramic surfaces treated with different etching procedures and bonding agents. MATERIALS AND METHODS: Monolithic CAD/CAM ceramic specimens (N = 120; n = 40 each group) of feldspathic ceramic Vita Mark II, resin nanoceramic Lava Ultimate, and hybrid ceramic Vita Enamic were fabricated (14 × 12 × 3 mm). Ceramic specimens were separated into four subgroups (n = 10) according to type of surface treatment and bonding onto the ceramic surface. Within each group, four subgroups were prepared by phosphoric acid, hydrofluoric acid, Transbond XT primer, and Clearfill Ceramic primer. Mandibular central incisor metal brackets were bonded with light-cure composite. The SBS data were analyzed using three-way analysis of variance (ANOVA) and Tukey HSD tests. RESULTS: The highest SBS was found in the Vita Enamic group, which is a hybrid ceramic, etched with hydrofluoric acid and applied Transbond XT Adhesive primer (7.28 ± 2.49 MPa). The lowest SBS was found in the Lava Ultimate group, which is a resin nano-ceramic etched with hydrofluoric acid and applied Clearfill ceramic primer (2.20 ± 1.21 MPa). CONCLUSIONS: CAD/CAM material types and bonding procedures affected bond strength ( P < .05), but the etching procedure did not ( P > .05). The use of Transbond XT as a primer bonding agent resulted in higher SBS.

Effect of Hydrofluoric Acid Concentration and Etching Time on Bond Strength to Lithium Disilicate Glass Ceramic.

The aim of this study was to evaluate the influence of different concentrations of hydrofluoric acid (HF) associated with varied etching times on the microshear bond strength (µSBS) of a resin cement to a lithium disilicate glass ceramic. Two hundred seventy-five ceramic blocks (IPS e.max Press [EMX], Ivoclar Vivadent), measuring 8 mm × 3 mm thickness, were randomly distributed into five groups according to the HF concentrations (n=50): 1%, 2.5%, 5%, 7.5%, and 10%. Further random distribution into subgroups was performed according to the following etching times (n=10): 20, 40, 60, 120, and 20 + 20 seconds. After etching, all blocks were treated with a silane coupling agent followed by a thin layer of an unfilled resin. Three resin cement cylinders (∅=1 mm) were made on each EMX surface, which was then stored in deionized water at 37°C for 24 hours before testing. The µSBS was in a universal testing machine at a crosshead speed of 1 mm/min until failure. Data were submitted to two-way analysis of variance, and multiple comparisons were performed using the Tukey post hoc test (α=0.05). One representative EMX sample was etched according to the description of each subgroup and evaluated using scanning electron microscopy for surface characterization. The HF concentrations of 5%, 7.5%, and 10% provided significantly higher µSBS values than 1% and 2.5% (p<0.05), regardless of the etching times. For 1% and 2.5% HF, the etching times from 40 to 120 seconds increased the µSBS values compared with 20 seconds (p<0.05), but etching periods did not differ within the 5%, 7.5%, and 10% HF groups (p>0.05). The effect of re-etching was more evident for 1% and 2.5% HF (p<0.05). Different HF concentrations/etching times directly influenced the bond strength and surface morphology of EMX.

Effect of ceramic etching protocols on resin bond strength to a feldspar ceramic.

This study sought to evaluate the resin microtensile bond strength (MTBS) stability of a leucite-reinforced ceramic after different ceramic etching protocols. The microtensile test had 40 ceramic blocks (5×5×6 mm) assigned to five groups (n=8), in accordance with the following surface etching protocols: NE nonetched (control); 9HF: hydrofluoric (HF) acid etching (9%HF)+wash/dry; 4HF: 4%HF+wash/dry; 5HF: 5%HF+wash/dry; and 5HF+N: 5%HF+neutralizer+wash/dry+ultrasonic-cleaning. Etched ceramic surfaces were treated with a silane agent. Next, resin cement blocks were built on the prepared ceramic surface and stored for 24 hours in distilled water at 37°C. The specimens were then sectioned to obtain microtensile beams (32/block), which were randomly assigned to the following conditions, nonaged (immediate test) and aged (water storage for 150 days plus 12,000 thermal cycles), before the microtensile test. Bond strength data were submitted to one-way analysis of variance and Tukey test (α=0.05). Additional ceramic samples were subjected to the different ceramic etching protocols and evaluated using a scanning electron microscope (n=2) and atomic force microscopy (n=2). Aging led to a statistically significant decrease in the MTBS for all groups, except the untreated one (NE). Among the groups submitted to the same aging conditions, the untreated (NE) revealed inferior MTBS values compared to the 9HF and 4HF groups. The 5HF and 5HF+N groups had intermediate mean values, being statistically similar to the higher values presented by the 9HF and 4HF groups and to the lower value associated with the NE group. The neutralization procedure did not enhance the ceramic/resin cement bond strength. HF acid etching is a crucial step in resin/ceramic bonding.

A replica technique for studying the effect of fluoride solutions on enamel erosion.

UNLABELLED: The aim of this in vitro study was to develop a replica technique aimed at reproducing an enamel surface exposed to erosive challenge. The replica technique was then used to compare the effect of treating enamel with different fluoride (F) solutions using an in vitro erosion model. Human molar teeth were split in two (total n=34 specimens), and half of each specimen was isolated with impression material. Part I: 10 specimens were exposed to either 0.18% or 1.8% citric acid, the impression material was removed and replicas were prepared. All specimens and replica models were analysed by profilometry and SEM. Part II: 24 specimens were treated with native 0.1 mol/L F-solutions (HF, SnF2, NaF and TiF4), the impression material was removed, and the specimens were then exposed to 1.8% citric acid. Replicas were prepared and analysed by profilometry and SEM. The median height difference between the F-treated areas and the non-treated areas for each F-solution was measured. SEM micrographs were analysed qualitatively blind bytwo of the authors. RESULTS: Part I--Replicas showed good topographical reproduction of the tooth specimens. Part II--HF had a significantly greater erosion-inhibiting effect than the other fluoride solutions at 0.1 mol/L F as shown by profilometry. SEM revealed a clearly defined border between F-treated and non-treated surfaces only for specimens treated with HF- and TiF solutions. In conclusion, the present replica technique was able to differentiate between the effect of treating enamel with different fluorides against dental erosion in vitro. The technique should be tested further for possible use in situ and in vivo.

Microtensile bond strength of resin cement to a feldspathic ceramic.

OBJECTIVE: The purpose of this study was to evaluate the microtensile bond strength of resin cement to a feldspathic ceramic after treating the surface with (a) hydrofluoric (HF) acid, (b) air abrasion, (c) Er:YAG laser irradiation, (d) Nd:YAG laser irradiation, and (e) HF acid etching after either air abrasion or laser irradiation. BACKGROUND DATA: It is unknown whether the laser application or its combination with another treatment method can be used as a tool to roughen the surface of a feldspathic ceramic in order to increase the bond strength between the resin cement and ceramic surface. MATERIALS AND METHODS: Forty feldspathic ceramic blocks (Ceramco(TM)) were prepared and divided into eight equal groups (n = 5) according to the following surface treatments: no treatment; etching with 9.5% HF acid; air abrasion with 50 µm Al(2)O(3); Er:YAG laser irradiation; Nd:YAG laser irradiation; air abrasion plus acid etching; Er:YAG laser plus acid etching; and Nd:YAG laser plus acid etching. After surface treatment, a silane-coupling agent and resin cement (Panavia F(TM)) were applied to each block. After storing for 24 h at 37°C and thermocycling between 5°C and 55°C for 1000 cycles, the microtensile bond strength of each specimen was measured. RESULTS: The highest bond strength was obtained from HF acid etching. HF acid etching after each laser irradiation significantly increased the bond strength (p < 0.05). However, HF acid etching after air abrasion decreased bond strength when compared to air abrasion alone. CONCLUSIONS: HF acid etching is the most effective surface treatment method for a feldspathic ceramic. However, laser irradiation with either the Er:YAG or Nd:YAG laser is not an adequate method for improving the bond strength of Panavia F. The laser application should be combined with HF acid etching.

Effect of acidic fluoride treatments on early enamel erosion lesions--a comparison of calcium and profilometric analyses.

OBJECTIVE: The protective effect of fluoride solutions against acidic challenge on enamel was tested in vitro using calcium- and profilometer analyses. METHODS: HF-, SnF(2)-, TiF(4)- and NaF solutions (0.1M F(-), with a pH of 2.0, 2.9, 1.5, 7.3, respectively) and H(2)O were tested on a total of 60 enamel specimens divided into 10 groups. Prior to and after F-treatment five groups were exposed for 1 min to 0.01 M citric acid, and the other five groups for 10 min to 0.1M citric acid. Enamel specimens were measured by profilometry at baseline and before and after each acidic challenge. [Ca] in the collected citric acid samples was measured by atom absorption spectroscopy (AAS). DeltaCa and Delta surface height were calculated for each specimen and the data were analysed using one-way ANOVA, Tukeys test and Pearson r correlation. RESULTS: AAS showed that the acidic F-treatments significantly reduced enamel dissolution for both the 1 min and 10 min acidic challenge. Profilometry showed no significant differences between the F-solutions for the 1 min groups. Significant differences could be seen between the fluorides for the 10 min groups and there was a large correlation between the profilometric and AAS results. In conclusion, all fluoride solutions reduced enamel dissolution when specimens were exposed to citric acid. CONCLUSIONS: The profilometer was not sensitive enough to measure the effects of the different fluorides against a low acidic challenge. AAS was able to show these differences and for the 10 min acidic challenge there was a good correlation between the results from the two methods.

Effect of stannous fluoride and dilute hydrofluoric acid on early enamel erosion over time in vivo.

Recent experimental in vivo studies have shown that aqueous solutions of stannous fluoride (SnF(2)) and hydrofluoric acid (HF) can reduce enamel solubility after 5 min. The aim of this study was to evaluate the longer-term protective effect of SnF(2) (0.78%, pH 2.9) and HF (0.2%, pH 2.0) (both approximately 0.1 mol/l F) using the same experimental model. Labial surfaces of healthy anterior teeth (all four surfaces when possible, otherwise a pair of surfaces) in 103 subjects (n = 399 teeth) were exposed to citric acid (0.01 mol/l, pH 2.7). The acid was applied using a peristaltic pump (5 ml, 6 ml/min) and was collected in coded test tubes (etch I). The test solutions were then applied to the same surfaces of the teeth (1 min, 6 ml/min). After either 1, 7, 14 or 28 days, citric acid was again applied to the same surfaces and subsequently collected (etch II). Enamel solubility was examined by assessment of calcium concentration in etch I and etch II solutions using atom absorption spectroscopy. Median values were calculated for all time periods and statistical analysis was carried out using the Wilcoxon signed-ranks test. Results showed that HF reduced enamel solubility by 54 and 36% after 1 and 7 days, respectively. After 14 and 28 days, there was no longer any effect. SnF(2) showed no protective effect after the first day. Given these results, repeated application of HF and especially SnF(2) may be necessary to improve the protective effect of these fluorides, and this requires further testing.

The effects of acidic fluoride solutions on early enamel erosion in vivo.

Acidic fluoride solutions may reduce dental erosion. The aim of this study was to compare the effect of different acidic fluoride solutions on enamel dissolution using an established in vivo model. When possible 4 anterior teeth (255 teeth in a total of 67 subjects) were isolated and exposed to 0.01 M citric acid. The acid was collected in test tubes before (etch I) and 5 min after (etch II) application of test fluoride preparations. Acidic fluoride solutions (pH range 1.5-2.9), i.e. SnF(2), TiF(4) and hydrogen fluoride (HF) (all approx. 0.1 M F), HF (0.027, 0.055, 0.082 M F) and neutral NaF solution (0.1 M F) as control were applied to the labial surfaces of the teeth for 1 min (6 ml/min). Enamel dissolution was examined by chemical analysis of calcium content in the citric acid etch solutions using atom absorption spectrometry. The change in calcium concentration (DeltaCa) and the percentage of mean calcium reduction were calculated from the difference in calcium loss between etch I and etch II. Statistical analysis was carried out using the Wilcoxon signed rank test and Kruskal-Wallis tests with Dunn's multiple comparison. Results showed a mean DeltaCa of 0.671 mg/l (SD 0.625) for SnF(2), and ranged from 0.233 mg/l (SD 0.248) for the weakest HF solution to 0.373 mg/l (SD 0.310) for the strongest HF solution. This represented a 67% reduction in enamel dissolution for SnF(2) and a 40-76% reduction for the HF solutions. No reduction was observed for TiF(4) or NaF. The types of metal, pH and fluoride concentration are all important for the in vivo effect.

Preparing porcelain surfaces for optimal bonding.

When placing an indirect restoration such as a porcelain veneer, inlay, or onlay, the intaglio surface is typically treated in some fashion to ensure optimal bonding to the resin-based adhesives and luting cements required to affix it to the tooth tissues. A variety of surface preparation techniques have been advocated, including the use of acids, particle abrasion, various adhesives, and chemical couplers such as silane. There is often equivocation in the literature regarding the effectiveness of these materials and surface preparation techniques. This article will attempt to make some sense of the various methodologies currently advocated for the treatment of porcelain surfaces before placement.

Bonding to enamel/dentin etched with phosphoric and hydrofluoric acids.

Repairing porcelain intraorally allows clinicians to provide their patients with a conservative means of treating fractured or debonded restorations. This requires, however, the etching of both porcelain and tooth structure with etching solutions. It is thus relevant to understand the effect that different etching procedures have on shear bond strengths of composite resins to both dentin and enamel structures. Based on the results of this investigation, the authors recommend isolation of tooth structures and the etching of porcelain with hydrofluoric acid.

Análise da proliferaçäo endosteal após a colocaçäo de "discos" de titânio c.p. em coelhos, tratados por diferentes formas / Analysis of the endosseus proliferation after the titanium c.p. \"discs\" implantation in rabbits, by different treatments

Recentemente, tem tornado aparente que o sucesso do implante endosteal é largamente, se näo totalmente, determinado pela biocompatibilidade do material usado. Esta biocompatibilidade parece estar determinada näo somente pela natureza química do material, mas também pela propriedade micromorfológica da superfície do implante. Os resultados apresentam uma avaliaçäo histológica da cicatrizaçäo inicial da implantaçäo de discos de titânio c.p. com superfície porosa fixados endostealmente. Para testar esta avaliaçäo foram utilizados 12 coelhos machos com peso médio de 3,2 Kg., sendo que cada animal recebeu 2 discos de titânio c.p.. Em todos os animais, os discos de titânio foram utilizados para avaliaçäo histológica de crescimento ósseo...

Effects of glass ionomer cement, resin-based pit and fissure sealant and HF applications on occlusal caries in a developing country field trial.

The aim of this community-oriented study was to evaluate different methods to prevent fissure caries. The following products and measures were tested: 1) glass ionomer cement (GIC) applied by dentist; 2) same material applied by short term (3 days) trained personnel (teachers); 3) application of a 0.5% HF solution three times; 4) an established autopolymerized resin based sealant (Delton). The study was performed in Bangkok, Thailand, a city in a developing country experiencing increasing caries prevalence. Children with at least three sound permanent molars from two age groups, 7-8 and 12-13-yr-olds respectively were chosen from very low to medium socioeconomic level families. 1264 children were systematically assigned to experiment or control groups based on school and DMFT. For the younger age group, the 2 yr mean DFS occlusal increment in the Control group was 0.66 surfaces. Significantly lower increments were observed in the GIC experimental group: 0.17 surfaces applied by the teachers and 0.32 applied by dentist, corresponding to 74% and 52% reductions, respectively. The mean increment in the HF group was 0.44 surfaces, a 33% reduction in relation to the Control group. For the 12-13-yr-olds, the mean occlusal surface DF increment was 0.70 surfaces in the Control group. Almost no occlusal increment was found in the Delton group, 0.05 DFS, a 93% reduction. In the GIC Dentist group, the DFS increment was 0.48 and in the Teacher group 0.56, corresponding to 31% and 20% reduction, respectively. A slight and nonsignificant increase of caries in relation to the Control group was observed in the HF group.(ABSTRACT TRUNCATED AT 250 WORDS)

Mutans streptococci in a Thai population: relation to caries and changes in prevalence after application of fissure sealants.

The aims of this study were to evaluate the level of mutans streptococci in two groups of Thai (Bangkok) children; to relate the findings to caries prevalence and to the caries increment over 2 years, and to study whether different sealant and fluoride programmes affected levels of mutans streptococci over a 2-year period. The baseline survey comprised 1,114 children aged 12 years. For the sealant project, a minimum of three caries-free permanent molars was required; 752 children aged 12-13 and 512 children aged 7-8 years were distributed into five groups: control group, Delton fissure sealant group, glass ionomer fissure sealant applied by dentist (GIC-dentist group) or by school teachers given a 3-day course (GIC-teacher group), and an HF group (0.5% HF solution applied 3 times). The WHO standard criteria were used to record caries. Prevalence of mutans streptococci was estimated using the Strip mutans test. Mean DMFT (n = 1,114) of 12-years-olds was 2.96; 17% had Strip mutans class 0 (low level), 32% class 1, 33% class 2 and 18% class 3 (the corresponding mean DFT +/- SD for each mutans streptococci class was 1.84 +/- 2.33, 2.23 +/- 2.14, 3.18 +/- 2.75, and 3.59 +/- 3.01 respectively). For the 7- to 8-year-olds (n = 512), mean df teeth at baseline was 5.36 (d = 5.19; f = 0.17); 5% had Strip mutans class 0, 17% class 1, 33% class 2 and 45% class 3 (the corresponding mean df teeth was 3.19 +/- 2.5, 4.13 +/- 2.84, 4.89 +/- 2.94 and 6.39 +/- 3.16 respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of a fluoride solution on dentinal hypersensitivity.

This two-phase experiment assessed the effects over time of a solution containing 1.09% sodium fluoride, .40% stannous fluoride, and .14% hydrogen fluoride (.717% fluoride solution, DentinBloc) on pain associated with dentinal hypersensitivity. During phase I, 30 subjects demonstrating dentinal hypersensitivity to a blast of cool air were divided into three double blind experimental groups. After baseline data were collected for all subjects, one group was instructed to apply the .717% fluoride solution twice a day. A second group was instructed to apply a gel containing .04% stannous fluoride (Gel-Kam) twice a day. A third group was instructed to apply distilled water. Each subject was assessed at 2, 4, 8, and 16 weeks utilizing the "method of limits" with a standardized, repeatable cold thermal stimulus. The results of a two factor repeated ANOVA indicated that those subjects who applied the .717% fluoride solution reported significantly less sensitivity at the 2-week period than the other groups (P < .05). In addition, those subjects whose solution contained the 0.4% stannous fluoride reported significantly less sensitivity at the 4- to 8-week periods (P < .05). Phase II of the study assessed the .717% fluoride solution on a more precise time course. These included: immediately, 15 minute, 1 day, 1 week and 2 weeks. A one factor repeated ANOVA revealed that this effect presented 15-minute post application (P < .05) and continued throughout the testing periods. It was concluded that the fully active 0.717% fluoride solution was an effective agent in the control of dentinal hypersensitivity after two 1-minute applications.

[Blood pharmacokinetics of fluorine in man after the oral administration of nicomethanol hydrofluoride]. / Pharmacocinétique sanguine du fluor après administration orale chez l'homme du fluorhydrate de nicométhanol.

The pharmacokinetic parameters of fluoride have been studied, after a single oral administration to human volunteers of two fluoridated compounds: sodium fluoride, and a new organic fluoride salt, nicomethanol hydrofluoride. The results obtained with these two compounds were very similar, suggesting that no abnormal accumulation of fluoride in the body occurs after using nicomethanol hydrofluoride.