Influence of preliminary etching on the stability of bonds created by one-step self-etch bonding systems.

We evaluated the effects of preliminary etching of dentine on the stability of the bond created by one-step self-etch adhesives under different storage conditions. Adper Easy Bond (3M ESPE) and iBond Self-Etch (iBond SE; Heraeus Kulzer) were applied with an etch-and-rinse (i.e. after preliminary phosphoric acid etching for 15 s) or a self-etch approach. Resin-dentine bonded specimens were sectioned perpendicularly to the adhesive interface according to the 'non-trimming technique'. Beams were stored in artificial saliva for 24 h, 6 months, or 1 yr at 37°C, or in 10% NaOCl for 5 h at room temperature, and then stressed until failure; the microtensile bond strengths were calculated. Interfacial nanoleakage of additional teeth was evaluated using light microscopy or transmission electron microscopy. Adper Easy Bond showed higher bond strength than iBond SE, regardless of the dentine treatment. Similar microtensile bond strength results were obtained for teeth subjected to artificial ageing in 10% NaOCl for 5 h at room temperature and for teeth stored in artificial saliva for 6 months at 37°C. The additional etching step increased the microtensile bond strength for Adper Easy Bond and iBond SE. This study supports the use of one-step adhesives on etched dentine because of the increased bond strength compared with their application onto smear-layer-covered dentine, regardless of storage conditions.

Comparing efficacy of plaque removal using professionally applied manual and power toothbrushes in 4- to 7-year-old children.

PURPOSE: The purpose of this study was to evaluate in 4- to 7-year-olds the efficacy of plaque removal of 2 toothbrushes: (1) the Philips Sonicare for Kids (SFK) power toothbrush with 2 amplitude settings (A and B); and (2) the Oral-B Stages 3 toothbrush (MTB). METHODS: Sixty-eight children participated in a single-masked, randomized, split-mouth study. Only subjects with a Quigley Hein plaque index (modified by Turesky et al.; TQHI) of more than 1.8 were enrolled. Subjects were randomized to SFK A (low amplitude, 7°), SFK B (high amplitude, 9°), or MTB by quadrant and brushed by a dental hygienist. TQHI was scored at 1- and 2-minute intervals by quadrant by a masked examiner. Multivariate analysis of variances for a split-mouth design was applied, and P-values were adjusted using Dunnett-Hsu modification. RESULTS: Mean baseline TQHI(+SD) scores were 2.89+0.06, 2.96+0.07, and 2.89+0.05 for SFK A, SFK B, and MTB, respectively. Adjusted mean postbrushing overall percent reductions for SFK A, SFK B, and MTB were 41%, 42%, and 29% at 1 minute and 67%, 65% and 49% at 2 minutes, respectively. Differences between both SFK and MTB were statistically significant. CONCLUSIONS: The Philips SFK removed significantly more plaque than the Oral-B Stages 3 toothbrush at 1- and 2-minute intervals with professional brushing assistance in 4- to 7-year-old subjects.

Fourteen years clinical evaluation of leucite-reinforced ceramic inlays luted using two different adhesion strategies.

OBJECTIVES: Aim of the present prospective study was to clinically evaluate the long-term performance of two different luting-materials for leucite-reinforced glass-ceramic inlays/onlays after 14 years. METHODS: A total of 83 IPS-Empress-inlays/onlays were placed in 30 patients. Restorations were luted according to two different strategies: 43 restorations were fixed with a self-adhesive resin-cement (RelyXUnicem, RX), 40 restorations were inserted with VariolinkII-low (SV) after pretreatment with an etch-and-rinse multi-step adhesive. Recalls were performed after two weeks (n=83), two years (n= 82), four years (n=74) and 14 years (n=54). Two independent calibrated examiners evaluated all restorations using modified USPHS-criteria. Statistical analysis was performed using pairwise Mann-Whitney-U-test and Friedman-test (p < 0.05). RESULTS: After 14 years, 54 restorations in 22 patients were evaluated (eight patients equalling 29 inlays not available). Ten restorations had to be replaced (failure rate 12%); four (SV-group) showed bulk fractures and two (RX-group) exhibited marginal fractures at the 14-year recall. Overall, the SV-group revealed significantly better results regarding discoloration of the luting gap (p<0.05) compared to the RX-group. No statistically significant differences were computed between SV and RX for the remaining criteria at the respective recalls (p>0.05). However, statistically significant deteriorations were detected for both luting procedures over 14 years regarding "colour match", "marginal integrity" and "tooth integrity" (p<0.05). CONCLUSIONS: The self-adhesive resin-cement RelyXUnicem showed similar clinical performance to a conventional multi-step luting-procedure after 14 years for most of the test parameters with a slightly inferior performance of RelyXUnicem regarding discoloration of the luting gap. CLINICAL SIGNIFICANCE: The current study presents unique in-vivo long-term data on two adhesion-strategies for indirect ceramic single-tooth restorations. Differences in performance of the two luting methods after being challenged for 14 years in the oral environment are highlighted. However, the overarching survival rate justifies the recommendation of both methods for clinical routine.

Role of preliminary etching for one-step self-etch adhesives.

The aim of this study was to analyse the effect of preliminary phosphoric acid etching of enamel and dentine before the application of two, one-step self-etch adhesive systems. The systems were applied onto acid-etched or smear-layer-covered enamel and dentine. The treatment groups were as follows: group 1, Adper Easy Bond (3M ESPE) on etched substrate; group 2, Adper Easy Bond (control); group 3, iBond Self-Etch (Heraeus Kulzer) on etched substrate; and group 4, iBond Self-Etch (control). Enamel and dentine bond strengths were calculated using microshear and microtensile bond-strength tests. Additional specimens were prepared to evaluate nanoleakage at the dentine-adhesive interface and were investigated using light microscopy or transmission electron microscopy. Both adhesives demonstrated higher microshear bond strengths when enamel was pre-acid-etched with phosphoric acid (Adper Easy Bond 28.7 ± 4.8 MPa; iBond Self-Etch 19.7 ± 3.6 MPa) compared with controls (Adper Easy Bond 19.2 ± 3.3 MPa; iBond Self-Etch 17.5 ± 2.7 MPa) and increased microtensile bond strength when applied on acid-etched (Adper Easy Bond 35.8 ± 5.7 MPa; iBond Self-Etch 24.3 ± 7.9 MPa) vs. smear-layer-covered dentine (Adper Easy Bond 26.9 ± 6.2 MPa; iBond Self-Etch 17.6 ± 4.3 MPa). Adper Easy Bond showed lower nanoleakage than iBond Self-Etch, irrespective of preliminary etching. The results of this study support the use of phosphoric acid etching before the application of one-step self-etch adhesive systems.

IPS Empress inlays luted with a self-adhesive resin cement after 1 year.

PURPOSE: To prospectively compare the clinical performance of two different resin composites for luting IPS Empress inlays and onlays. METHODS: 83 IPS Empress restorations were placed in 30 subjects. All restorations were inserted under rubber dam. 43 inlays/onlays were luted with a self-adhesive resin cement [RelyX Unicem (RX)]. A multistep adhesive (Syntac) was used with Variolink II low viscosity (SV) and served as control (n=40). The restorations were evaluated after 2 weeks: Baseline = 1st recall (R1), after 6 months (R2) and after 1 year (R3) by two calibrated examiners using the modified USPHS criteria. RESULTS: From R1 to R3, one failure was noticed in the SV group (R2) due to marginal enamel chipping. After 1 year of clinical service, SV revealed significantly better results regarding color match and integrity inlay (Mann-Whitney U-test, P< 0.05). No statistically significant differences were observed between SV and RX for the remaining criteria (Mann-Whitney U-test, P>0.05).

Nanohybrid composite vs. fine hybrid composite in extended class II cavities: clinical and microscopic results after 2 years.

PURPOSE: To evaluate the clinical behavior of two different resin composites in Class II cavities over a period of 2 years in a controlled prospective split-mouth study. METHODS: 30 subjects received 68 direct resin composite restorations (Grandio bonded with Solobond M: n=36, Tetric Ceram bonded with Syntac: n=32) by one dentist in a private practice. All restorations were replacement restorations, 24 cavities (35%) revealed no enamel at the bottom of the proximal box, in 33 cavities (48%) the proximal enamel width was < 0.5 mm. The restorations were examined according to modified USPHS criteria at baseline, and after 0.5, 1, and 2 years. At each recall, impressions were taken to prepare replicas. Replicas of 44 selected subjects were assessed for marginal quality under a stereo light microscope (SLM) at x130, and 22 replicas were assessed under a SEM at x200. RESULTS: Both recall rate and survival rate were 100% after 2 years of clinical service. No significant difference was found between the restorative materials (P > 0.05; Mann-Whitney U-test). A significant deterioration was found over time for marginal integrity, tooth integrity, restoration integrity and proximal contact (P < 0.05; Friedman test). SLM and SEM analysis of restoration margins only revealed differences in the amount of detectable perfect margins, in favor of Tetric Ceram (P < 0.05). Both materials performed satisfactorily over the 2-year observation period.

New Approaches in Bonding to Glass-Ceramic: Self-Etch Glass-Ceramic Primer and Universal Adhesives.

PURPOSE: To investigate the tensile bond strength of silane-containing universal adhesives and self-etch glass-ceramic primer to lithium disilicate glass ceramics (LS2). MATERIALS AND METHODS: 960 rectangular LS2 bars (7 mm x 3 mm x 9 mm, IPS e.max CAD, Ivoclar Vivadent) were manufactured and divided into 4 groups (n = 240). Group 1 was etched with ~5% hydrofluoric acid (HF) for 20 s (VITA Ceramics Etch, Vita Zahnfabrik), group 2 was etched with ~5% HF for 20 s and silanized (ESPE Sil, 3M Oral Care), group 3 was pre-treated with a self-etching glass-ceramic primer (Monobond Etch & Prime, Ivoclar Vivadent, and group 4 received no pre-treatment. Three universal adhesives (iBOND Universal, Heraeus Kulzer; Scotchbond Universal Adhesive, 3M Oral Care; Futurabond U, Voco) were applied to the differently pre-treated surfaces, with Heliobond (Ivoclar Vivadent) serving as control. The bars from each group were paired and luted perpendicularly, forming a square bonded area of 9 mm2, using Variolink II (Ivoclar Vivadent) with a constant pressure of 10 N, followed by light curing (40 s at 800 mW/cm2, Elipar Trilight, 3M Oral Care). The resulting specimens were stored for 24 h at 37°C in distilled water. Half of the specimens of each group were submitted to tensile bond strength testing, the other half were thermocycled ([TC] 5000 cycles, 5°C/55°C, 30-s dwell time) before testing. Data were analyzed using three-way ANOVA (α = 0.05). RESULTS: Group 2 (HF etched and silanized) and group 3 (self-etching glass-ceramic primer) reached significantly higher mean bond strengths than did groups 1 (only HF etched) and 4 (no pre-treatment). CONCLUSION: Additional silanization of HF-etched LS2 statistically signficantly improved the tensile bond strength of the silane-containing universal adhesive (Scotchbond Universal). The self-etching glass-ceramic primer Monobond Etch & Prime achieved mean bond strengths that did not differ significantly from HF-etched and silanized specimens.

Selective enamel etching reconsidered: better than etch-and-rinse and self-etch?

PURPOSE: This study evaluated the marginal quality of differently bonded direct resin composite restorations in enamel and dentin, before and after thermomechanical loading (TML). Special attention was focussed on the performance of selective enamel etching, etch-and-rinse, and self-etching adhesives. MATERIALS AND METHODS: Eighty MO cavities with proximal margins beneath the cementoenamel junction were prepared in extracted human third molars. Direct resin composite restorations (Tetric EvoCeram, n=8) were placed with 4-step selective enamel etching (Syntac SE), 4-step etch-and-rinse (Syntac ER), 2-step etch-and-rinse (XP Bond, Scotchbond 1 XT/Single Bond Plus), 2-step self-etching (AdheSE, Clearfil SE Bond), 2-step self-etching with selective enamel etching (AdheSE SE, Clearfil SE Bond SE), and 2-step self-etching with etch-and-rinse (AdheSE TE, Clearfil SE Bond TE). Marginal gaps were analyzed using epoxy resin replicas under a scanning electron microscope at 200X magnification. RESULTS: Initially, high percentages of gap-free margins were identified for all adhesives. After TML, the results were as follows: (A) Enamel margins: When phosphoric acid was used on enamel, results were constantly higher (approximately 90%) compared with two-step self-etchin adhesives (approximately 70%; p < 0.05). (B) Dentin margins: No statistical differences were found when etch-and-rinse and selective etch approaches were compared (59% to 64%; p > 0.05). When self-etching adhesives were used as per manufacturers' directions, dentin margins exhibited the best marginal quality (74% to 82%; p < 0.05). When self-etching adhesives were used under etch-and-rinse conditions, marginal quality in dentin was significantly reduced to 35% to 42% (p < 0.05). CONCLUSION: Enamel bonding was generally more effective with phosphoric-acid etching. Enamel bonding performance of 2-step self-etching adhesives was improved when phosphoric acid was applied on enamel selectively.

Leucite-reinforced glass ceramic inlays and onlays after 12 years.

PURPOSE: This controlled clinical trial aimed to evaluate IPS Empress inlays and onlays over 12 years. The null hypothesis was that different luting resins would have no influence on clinical outcome. MATERIALS AND METHODS: In the course of a prospective clinical long-term trial, 96 ceramic inlays and onlays were placed in 34 patients using one adhesive (Syntac) and four different luting composites (Tetric, Variolink Low, Variolink Ultra, Dual Cement). Recalls were carried out by two calibrated investigators using modified USPHS codes and criteria at baseline, 1, 2, 4, 6, 8, and 12 years. RESULTS: Fifteen of the 96 restorations had to be replaced (failure rate 16%; Kaplan-Meier); 12 of them suffered bulk fractures. After twelve years of clinical service, significantly more bulk fractures were found when light-curing composite was used for luting (p < 0.05). Fractures were noticed between 3 and 4 years of clinical service and later after 11 to 12 years; aside from those times, no single fracture occurred. Secondary caries was not observed. CONCLUSION: IPS Empress inlays and onlays exhibited satisfactory clinical outcomes over a 12-year clinical period. Restorations luted with dual-cured resin composites revealed significantly fewer bulk fractures.

Totally bonded ceramic inlays and onlays after eight years.

PURPOSE: The aim of the present study was to clinically evaluate the effect of two different adhesive/resin composite combinations for luting IPS Empress inlays with a special focus on luting gap wear and marginal adaptation. MATERIALS AND METHODS: In the course of a controlled prospective clinical split-mouth study, 94 IPS Empress restorations were placed in 31 patients. The inlays were luted with EBS Multi + Compolute (EC; 3M ESPE) or with Syntac + Variolink II low (SV; Ivoclar Vivadent). At baseline and after 0.5, 1, 2, 4, and 8 years, the ceramic restorations were examined according to modified USPHS codes and criteria. Thirty-five selected samples were investigated under an SEM regarding morphological changes; marginal quality analysis was carried out using a stereo light microscope, and luting composite wear was scanned with a profilometer. RESULTS: Eight patients (including 25 restorations) missed the recalls; the recall rate at the last investigation was 72%. After 96 months of clinical service, seven restorations in five patients (six EC, one SV) had to be replaced due to hypersensitivities (n = 5) or inlay fractures (n = 2) resulting in a survival rate of 90%. Over the 8-year period, the restorations revealed no statistically significant differences in terms of surface roughness, color matching, proximal contact, sensitivity, or complaints (p > 0.05, Friedman test). Significant deteriorations were found for marginal integrity (p < 0.05). No significant differences were observed for the different luting systems (p = 0.096, Log rank test/ Mantel Cox). Marginal analysis revealed no statistical difference among the materials (p > 0.05; Mann-Whitney U-test), however, the scans of the luting gap showed that Compolute was more prone to wear (p < 0.05). CONCLUSION: For luting of ceramic inlays, no difference between the two luting systems was detectable. The overall failure rate after 8 years was 10%.

Membrane association and remodeling by intraflagellar transport protein IFT172.

The cilium is an organelle used for motility and cellular signaling. Intraflagellar transport (IFT) is a process to move ciliary building blocks and signaling components into the cilium. How IFT controls the movement of ciliary components is currently poorly understood. IFT172 is the largest IFT subunit essential for ciliogenesis. Due to its large size, the characterization of IFT172 has been challenging. Using giant unilamellar vesicles (GUVs), we show that IFT172 is a membrane-interacting protein with the ability to remodel large membranes into small vesicles. Purified IFT172 has an architecture of two globular domains with a long rod-like protrusion, resembling the domain organization of coatomer proteins such as COPI-II or clathrin. IFT172 adopts two different conformations that can be manipulated by lipids or detergents: 1) an extended elongated conformation and 2) a globular closed architecture. Interestingly, the association of IFT172 with membranes is mutually exclusive with IFT57, implicating multiple functions for IFT172 within IFT.

Adhesive luting revisited: influence of adhesive, temporary cement, cavity cleaning, and curing mode on internal dentin bond strength.

PURPOSE: To evaluate microtensile bond strength to Class I cavity floor dentin beneath adhesive inlays that were luted with different adhesives, temporary cements, cleaning methods, and curing modes. MATERIALS AND METHODS: Occlusal cavities (4 x 4 mm, depth 3 mm) were prepared in 96 extracted human third molars. One part of the cavities was temporized with different temporary cements, which were removed after one week using three techniques (scaler or air polishing with Prophypearls or ClinPro powder). Direct resin composite inlays (Clearfil AP-X) were then placed with the luting composite Calibra using three adhesives (XP BOND/SCA, Syntac, OptiBond FL). Teeth were cut into beams and after 24 h of water storage at 37 degrees C, the sticks were subjected to microtensile bond strength evaluation. Samples were subjected to SEM fractographic analysis of failed interfaces. RESULTS: Contamination with temporary cement reduced dentin bond strengths (p < 0.05). Removing remnants of cements with Prophypearls air polishing resulted in the lowest bond strengths (p < 0.05). Separate light curing of the adhesives did not produce higher dentin bond strengths (p > 0.05). Syntac still worked when Heliobond was omitted (p > 0.05). Immediate dentin sealing prior to temporizing increased internal bond strength (p < 0.05). CONCLUSION: The dual-cured adhesive provided higher internal bond strengths between adhesive inlays and dentin. Contamination of dentin with temporary cements is a hazard for excellent dentin adhesion of adhesive inlays. Therefore, immediate dentin sealing and resin coating is promising.

The effect of different air-polishing powders on dentin bonding.

PURPOSE: Air-polishing is routinely used for professional tooth cleaning. Therefore, the aim of this in vitro study was to evaluate the influence of different air-polishing powders on dentin bonding. MATERIALS AND METHODS: Dentin bond strengths of a resin composite (Clearfil AP-X) bonded with different classes of adhesives (4-step etch-and-rinse: Syntac; 3-step etch-and-rinse: OptiBond FL; 2-step etch-and-rinse: Single Bond Plus; 2-step self-etching: AdheSE, Clearfil SE Bond, Clearfil Protect Bond, One Coat Self-Etch Bond; all-in-one/mix: Xeno III; all-in-one/no mix: Clearfil S3 Bond, G-Bond) were measured on flattened dentin surfaces. In test groups, specimens were air polished with Prophypearls (calcium carbonate) or ClinPro Prophypowder (glycine) prior to bonding. Microtensile bond strengths were evaluated after 24 h of storage at 37 degrees C in water. Surfaces and resin-dentin interfaces were observed by SEM, TEM, and CLSM. RESULTS: Mean bond strengths varied from 18 to 73 MPa in control groups. Calcium carbonate air polishing generally caused significantly reduced dentin bond strengths (p < 0.05). TEM exhibited severe nanoleakage after calcium carbonate air polishing. Glycine did not affect dentin bonding performance of the adhesives under investigation. CONCLUSION: Calcium carbonate air polishing should be avoided when dentin-bonded restorations are applied. Glycine powder is an alternative.

Bulk-fill resin composites: polymerization properties and extended light curing.

OBJECTIVES: The aim was to evaluate the polymerization properties of bulk-fill resin composites using two different light-curing protocols, in terms of degree of conversion (%DC), Vickers hardness (HV), polymerization volume shrinkage (PVS) and polymerization shrinkage stress (PSS) and compare them to conventional condensable and flowable resin composites. MATERIALS AND METHODS: Filtek BulkFill (FBF, 3MESPE, Germany), SDR (Dentsply, Germany), TetricEvoCeram BulkFill (TBF, Ivoclar-Vivadent, Liechtenstein), Venus BulkFill (VBF, Heraeus, Germany), X-traBase (XTB, Voco, Germany), FiltekZ250 (3MESPE) and Filtek Supreme XTE Flowable (FSF, 3MESPE) were investigated. Light-curing was performed for 30 s or according to manufacturers' instructions (1200 mW/cm2, Bluephase20i, Ivoclar-Vivadent). For %DC and HV, discs (n=5) of 2 or 4 mm in thickness were prepared and stored for 24h in distilled water at 37°C. %DC was determined by FTIR-ATR-spectroscopy. %DC and HV were measured at the top and bottom of the specimens. PVS was measured using Archimedes method (n=6). PSS measurements (n=10) were carried out using 5 mm diameter PMMA rods as bonding substrates with a specimen height of 1 mm in a universal testing machine. Data were analyzed using one- and two-way ANOVA (α=0.05). RESULTS: Except Z250 in the manufacturers' light-curing mode, all materials showed no significant inferior %DC at 4 mm thickness. When light cured for 30 s Z250 had no significant differences in %DC at 2 or 4 mm when compared to top. FBF, TBF, FSF and Z250 displayed significant reduced HV at 4 mm in both curing modes. Z250 and TBF showed the lowest PVS and FSF the highest PSS in both curing modes. SIGNIFICANCE: All investigated bulk-fill composites obtained sufficient polymerization properties at 4 mm depth. Enhanced curing time improved the investigated polymerization properties of bulk-fills and Z250.

Leucite-reinforced glass ceramic inlays luted with self-adhesive resin cement: a 2-year in vivo study.

OBJECTIVES: Aim of the present prospective controlled clinical study was to compare the clinical performances of two different cementation procedures to lute IPS Empress inlays and onlays. METHODS: Eighty-three IPS Empress restorations (70 class-II inlays, 13 onlays/47 premolars, 36 molars) were placed in 30 patients (19 females/11 males, mean age=39 years). Two cementation procedures were tested: group 1: forty-three restorations were luted with a self-adhesive resin cement (RelyX Unicem, RX, 3M ESPE); group 2: forty restorations were luted with an etch-and-rinse multistep adhesive (Syntac Classic, Ivoclar-Vivadent) and Variolink II low (SV, Ivoclar-Vivadent). All restorations were evaluated after 2 weeks (baseline=1st recall=R1, n=83), 6 months (R2, n=83), 1 year (R3, n=82), and 2 years (R4, n=82) by two independent blinded calibrated examiners using modified USPHS criteria. RESULTS: From R1 to R4, one failure occurred in the SV group (at R2) due to marginal enamel chipping. After 2 years of clinical service (R4), better marginal and tooth integrity (p<0.05) was found in group 2 (SV) compared to the use of the self-adhesive cement (RX, group 1), while no differences were found for all remaining investigated criteria (p>0.05). The absence of enamel in proximal boxes (10% with no enamel and 51% of the restorations with less than 0.5mm enamel width at the bottom of the proximal box) did not affect marginal performance (p>0.05). SIGNIFICANCE: The self-adhesive resin cement RelyX Unicem showed clinical outcomes similar to a conventional multi-step cementation procedure after 2 years of clinical service for most of the tested criteria.