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PubMed1998

Sealing ability of two "compomers" applied with and without phosphoric acid treatment for Class V restorations in vivo.

STATEMENT OF PROBLEM: "Compomers" are being used with increasing frequency in Europe and North America. PURPOSE: This study evaluated the marginal seal of two compomers in vivo. MATERIAL AND METHODS: Periodontally involved teeth, scheduled for extraction, were selected. Four groups of a combination of materials were used (Dyract with Dyract-PSA primer, group 1; Dyract with Prime and Bond 2.0, group 2; Compoglass with SCA primer, group 3; and Compoglass with Syntac Single Component, group 4). The restorations were made in a standardized shaped cavity, across the cementoenamel junction, and the teeth were extracted after 2 to 3 months of clinical service. The specimens were kept in a solution of 2% methylene blue for 24 hours. After being embedded in epoxy resin, sections were made with a low speed saw along the longitudinal axis of the teeth. The examination of dye penetration was made with a microscope at a magnification of x20 and scoring was done at both coronal and apical sites. Kruskal-Wallis statistical analysis was performed at 5% significance level. RESULTS: Groups 2 and 4 scored significantly less than groups 1 and 3 and for groups 2 and 4, 30% of the restorations exhibited leakage. CONCLUSION: These restoration systems did not completely prevent leakage either at the incisal or the cervical margins. Therefore the use of an enamel-dentin bonding system in combination with the proprietary compomer is recommended.

Acid Etching, Dental↗
PubMed2000

Microtensile bond strengths of seven dentin adhesive systems.

OBJECTIVES: The purpose of this study was to evaluate the microtensile bond strengths of seven dentin adhesive systems (Solid Bond, EBS-Multi, PermaQuik, One Coat Bond, Gluma One Bond, Prime & Bond NT/NRC and Clearfil Liner Bond 2V) and their respective fracture modes. METHODS: Superficial occlusal dentin of extracted human molars was exposed, finished with wet 600-grit silicon carbide paper, and a block of resin composite bonded with the above adhesives according to the manufacturers' instructions. The teeth were kept in tap water for 24 h at 37 degrees C, sectioned to obtain three or four bar-shaped specimens, which were then shaped to an hour-glass form of 1.2 +/- 0.02 mm diameter. The specimens were stressed at a crosshead speed of 1 mm/min until rupture of the bond. The mean bond strengths were compared using one-way ANOVA and LSD tests. The frequency of fracture modes was compared using Kruskal-Wallis and Mann-Whitney U-tests. RESULTS: Mean microtensile bond strengths ranged from (17.8 +/- 7.0) MPa for Solid Bond to (36.0 +/- 8.1) MPa for Clearfil Liner Bond 2V. The bond strength of Clearfil Liner Bond 2V and PermaQuik (30.8 +/- 8.5 MPa) were not significantly different, and were higher than all other materials. Bond strengths of Solid Bond (17.8 +/- 7.0) MPa, EBS-Multi (18.7 +/- 5.0) MPa, One Coat Bond (21.9 +/- 5.6) MPa, and Gluma One Bond (23.4 +/- 5.2) MPa were not significantly different. SEM examination indicated that Solid Bond, EBS-Multi and One Coat Bond showed no significant difference in failure modes but were significantly different from PermaQuik, Prime & Bond NT/NRC and Clearfil Liner Bond 2V. SIGNIFICANCE: The self-etching primer system, Clearfil Liner Bond 2V, provided the simplest bonding technique, and together with PermaQuik exhibited greatest bond strength to dentin.

Analysis of Variance↗
PubMed2001

"No-bottle" vs "multi-bottle" dentin adhesives--a microtensile bond strength and morphological study.

PURPOSE: To compare the adhesive capability of the new adhesive Prompt L-Pop (ESPE) with that of two total-etch adhesive systems-EBS Multi (ESPE) and Prime&Bond NT (Dentsply). METHODS: Extracted human molars were bonded and prepared for microtensile dentin bond strength (microTBS) testing using Prompt L-Pop, EBS Multi, and Prime&Bond NT combined with Pertac II (composite) or Hytac Aplitip (compomer). Prompt L-Pop was applied using five different protocols: (1) as an "all-in-one" self-conditioning adhesive, as per manufacturer's instructions (LP); (2) as a self-etching primer combined with a separate bonding resin (LP/self-etch 2-step); (3) as a classical primer used upon etching dentin with phosphoric acid, followed by a bonding resin (LP/total-etch 3-step); (4) as a multi-application "all-in-one" self-conditioning adhesive (LP/multi-coat) to leave a visibly glossy dentin surface; and (5) as a filled adhesive, upon adding quartz fillers to its composition (LP/filled). After 24h of storage in water at 37 degrees C the microTBS were measured in an Instron machine. Corresponding interfaces of the same specimens were micromorphologically analyzed using SEM and TEM. RESULTS: When used with a composite resin, LP/filled and LP/multi-coat resulted in significantly higher microTBS than LP. The addition of an extra adhesive bonding resin (LP/self-etch 2-step) had no effect on bond strength. The use of Prompt L-Pop as a primer of a fourth-generation adhesive (LP/total-etch 3-step) replacing the EBS Multi primer, resulted in lower bond strengths than those of the original EBS Multi. LP/multi-coat showed similar microTBS to Prime&Bond NT (P&BNT). When used with a compomer, LP exhibited higher bond strengths than when used with the resin composite and was as effective as the experimental groups LP/filled and LP/multi-coat and the control group P&BNT. The SEM evaluation showed an inconsistent hybrid layer for the LP specimens, whereas in both the LP/filled and LP/multi-coat specimens a hybrid layer was clearly evident. Under the TEM all groups displayed dentin hybridization with dissolved smear plugs in the specimens that had been conditioned with Prompt L-Pop without a separate etching step. In many tubules of specimens conditioned with LP (as per manufacturer's instructions), fillers of the resin composite were present within the dentinal tubules. CONCLUSIONS: When combined with a resin composite, Prompt L-Pop resulted in statistically lower bond strengths when applied in one layer than when applied in multiple layers. Prompt L-Pop also resulted in higher bond strengths when used with a polyacid-modified composite resin than with a composite resin. When applied in multiple coats, Prompt L-Pop results in bond strengths that are not statistically different from those of Prime&Bond NT, a total-etch adhesive.

Acid Etching, Dental↗
PubMed2001

Aggressiveness of contemporary self-etching adhesives. Part II: etching effects on unground enamel.

OBJECTIVES: The aggressiveness of three self-etching adhesives on unground enamel was investigated. Ultrastructural features and microtensile bond strength were examined, first using these adhesives as both the etching and resin-infiltration components, and then examining their etching efficacy alone through substitution of the proprietary resins with the same control resins. METHODS: For SEM examination, buccal, mid-coronal, unground enamel from human extracted bicuspids were etched with either Clearfil Mega Bond (Kuraray), Non-Rinse Conditioner (NRC; Dentsply DeTrey) or Prompt L-Pop (ESPE). Those in the control group were etched with 32% phosphoric acid (Bisco) for 15s. They were all rinsed off prior to examination of the etching efficacy. For TEM examination, the self-etching adhesives were used as recommended. Unground enamel treated with NRC were further bonded using Prime&Bond NT (Dentsply), while those in the etched, control group were bonded using All-Bond 2 (Bisco). Completely demineralized, resin replicas were embedded in epoxy resin for examination of the extent of resin infiltration. For microtensile bond strength evaluation, specimens were first etched and bonded using the self-etching adhesives. A second group of specimens were etched with the self-etching adhesives, rinsed but bonded using a control adhesive. Following restoration with Z100 (3M Dental Products), they were sectioned into beams of uniform cross-sectional areas and stressed to failure. RESULTS: Etching patterns of aprismatic enamel, as revealed by SEM, and the subsurface hybrid layer morphology, as revealed by TEM, varied according to the aggressiveness of the self-etching adhesives. Clearfil Mega Bond exhibited the mildest etching patterns, while Prompt L-Pop produced an etching effect that approached that of the total-etch control group. Microtensile bond strength of the three experimental groups were all significantly lower than the control group, but not different from one another. When the self-etching adhesives were replaced with the control adhesive after etching, bond strengths of NRC/Prime&Bond NT and Prompt L-Pop were not significantly different from that of the control group, but were significantly higher than that of Clearfil Mega Bond. SIGNIFICANCE: Both etching efficacy and strength of the resins are important contributing factors in bonding of self-etching adhesives to unground enamel.

Acid Etching, Dental↗
PubMed2002

Comparison of pulse activation vs conventional light-curing on marginal adaptation of a compomer conditioned using a total-etch or a self-etch technique.

OBJECTIVES: This study investigated the effect of two factors: conditioning methods and light-curing techniques on the marginal adaptation of Dyract AP (Dentsply DeTrey, Germany). The 'pulse activation' curing technique was compared with a conventional light-curing technique for their effectiveness in reducing marginal gaps in restorations that were conditioned with three different protocols. MATERIALS AND METHODS: Cylindrical cavities, 3mm in diameter, were prepared in extracted human molar teeth. They were restored with Dyract AP using Prime&Bond NT (PBNT; Dentsply DeTrey) as the adhesive. Cavities were etched with: Conditioner36/PBNT (group 1), Non-Rinse Conditioner (NRC)/PBNT (group 2), and PBNT only (group 3). Either conventional or the 'pulse activation' technique was used for light-curing of the material. Epoxy resin replicas were obtained from longitudinal sections of the specimens, and the restoration-tooth interfaces were examined using scanning electron microscopy. Marginal qualities along the resin-dentin interfaces were further measured using image analysis and analyzed using nonparametric statistical methods. RESULTS: With the conventional curing technique, enamel margin fractures were frequently observed. Marginal gaps were found along the compomer-dentin interfaces irrespective of the conditioning protocol. A significantly lower percentage of gap-containing margins were found in cavities that were conditioned with 36% phosphoric acid. With the 'pulse activation' technique, no marginal gap was found along compomer-dentin interfaces that were etched with either Conditioner36 or NRC. More than 90% of the total margin length were excellent. No cohesive failure of enamel could be observed along cavosurface margins. SIGNIFICANCE: The 'pulse activation' curing technique significantly improves the marginal integrity of Dyract AP when Conditioner36/Prime&Bond NT and NRC/Prime&Bond NT are used as conditioning/bonding systems. The use of Prime&Bond NT without etching is not recommended, as marginal gaps are present irrespective of the curing techniques employed.

Acid Etching, Dental↗
PubMed2002

The effect of thermocycling regimens on the nanoleakage of dentin bonding systems.

OBJECTIVES: The purpose of this study was to compare nanoleakage associated with polished and fractured specimens, and evaluate the effects of thermocycling on nanoleakage. METHODS: The dentin bonding systems used in this study were PermaQuik and Prime and Bond NT (PBNT). Flat occlusal dentin surfaces and class V cavities from extracted human molars were bonded with one of the dentin bonding systems. With or without thermocycling, samples were immersed in a 50% w/v solution of silver nitrate for 24h, and exposed to photodeveloping solution for 8h. The specimens were cut or fractured, and mounted on stubs, carbon coated and observed in a Field Emission-SEM using backscattered electron mode. RESULTS: Polished and fractured specimens showed similar nanoleakage patterns for both dentin-bonding systems. Thermocycling with regimens of different temperatures and number of cycles did not result in different nanoleakage patterns and leakage lengths in controls and thermocycled groups. PBNT combined with non-rinse conditioner (NRC) produced no significant difference in nanoleakage length, but a somewhat different nanoleakage pattern, compared with PBNT and 34% phosphoric acid. SIGNIFICANCE: Thermocycling does not have an effect on nanoleakage of dentin bonding systems. The smearing effect from sectioning and polishing procedures does not affect the nanoleakage result.

Acid Etching, Dental↗
PubMed2000

Marginal adaptation of a new compomer under different conditioning methods.

OBJECTIVES: This in vitro study evaluated the marginal adaptation of compomer restorations placed using three different conditioning protocols. MATERIALS AND METHODS: Thirty extracted caries-free molars with 3mm diameter cylindrical cavity preparations were divided randomly into three groups based upon the conditioning treatment used: (I) 36% phosphoric acid; (II) non-rinse conditioner (NRC, Dentsply DeTrey); and (III) no conditioning. Cavities were restored with Dyract AP using Prime&Bond NT (Dentsply DeTrey) as an adhesive. Silicone impressions of the briefly etched enamel surfaces were taken after finishing the restorations. Each sample was then longitudinally sectioned and impressions were taken. Epoxy resin replicas were prepared for SEM analysis. Qualitative and quantitative assessment were performed separately for the enamel- and dentine-restorative interface. RESULTS: Enamel fractures and open margins along the enamel-restorative margin were observed in some specimens in each group. No statistically significant difference was found in the percentage of gaps/cohesive failures between specimens prepared using different conditioning methods. For the dentine-restorative interface, uniform hybrid layers and long resin tags were often observed in Groups I and II. The hybrid layer in Group III was irregular and discontinuous along the interface. A significant difference (p<0.01) in the proportion of marginal gap was found between Group I (2%) and Group III (30%). CONCLUSIONS: Pre-treating the cavity with 36% phosphoric acid significantly improved the adaptation of the compomer and adhesive to dentine compared with no etching. The marginal quality at the enamel-compomer interface was not affected by the conditioning method used.

Acid Etching, Dental↗
PubMed1999

Shear bond strength of composite, glass ionomer, and acidic primer adhesive systems.

The purpose of this study was to determine the shear bond strengths of orthodontic brackets bonded with one of three methods: (1) a glass ionomer adhesive with a 20% polyacrylic acid enamel conditioner; (2) a composite resin adhesive used with 37% phosphoric acid etchant and a conventional primer; or (3) the same composite resin used with an acidic primer that combines the etchant with the primer in one application. The brackets were bonded to the teeth according to one of three protocols. Group I teeth were etched with 37% phosphoric acid and bonded with Transbond XT (3M Unitek, Monrovia, Calif) following the manufacturer's instructions. Group I acted as the control group. Group II teeth were etched with an acidic primer (Clearfil Liner Bond 2. J.C. Moritta Kuraway, Japan) that contains both the acid (Phenyl-P) and the primer (HEMA and dimethacrylate) and was placed on the enamel for 30 seconds; the adhesive used to bond the brackets was Transbond XT as in Group I. Group III teeth were etched with 20% polyacrylic acid and the brackets were bonded with Fuji Bond LC (G.C. America, Chicago, Ill). A steel rod with one flattened end was attached to the crosshead of a Zwick test machine (Zwick GmbH & Co, Ulm, Germany). An occlusogingival load was applied to the bracket, producing a shear force at the bracket-tooth interface. The results indicated that the resin/phosphoric acid adhesive system (control group) provided the strongest shear bond strength x = 10.4 +/- 2.8 MPa). The glass ionomer adhesive system provided a significantly lower bond strength (x = 6.5 +/- 1.9 MPa). The least shear bond strength was present when the acidic primer was used with an orthodontic adhesive (x = 2.8 +/- 1.9 MPa). In the present study, the use of either a fluoride-releasing glass ionomer or an acidic primer in combination with an available orthodontic composite adhesive resulted in a significantly reduced shear bond strength when compared with that of the conventional composite resin adhesive system. At the present time, the orthodontist and the patient are better served by using phosphoric acid/composite resin adhesive system or other equivalent systems that provide a clinically reliable bond strength between the bracket, the adhesive, and the enamel surface.

Acid Etching, Dental↗
PubMed2004

A molecularly imprinted polymer-based synthetic transaminase.

The design, synthesis, and evaluation of a molecularly imprinted polymer transaminase mimic is described. Methacrylic acid-ethylene glycol dimethacrylate copolymers were synthesized using, as a template, a transition state analogue (TSA) for the reaction of phenylpyruvic acid and pyridoxamine to yield phenylalanine and pyridoxal. Polymer suitability was established on the basis of (1)H NMR studies of template-functional monomer interactions. Polymer recognition characteristics were examined in a series of HPLC studies using the polymers as chromatographic stationary phases. Selectivity for the TSA, relative to substrates and products, was observed in both aqueous and nonpolar media. In the latter case (chloroform/AcOH, 96:4), an enantioseparation factor (alpha) of 2.1 was obtained, and frontal chromatographic studies revealed the presence of 11.9 +/- 0.2 micromol g(-1) (dry weight) of enantioselective sites. Polymers imprinted with the l-form of the oxazine-based TSA induced a 15-fold enhancement of the apparent reaction rate (app. V(max) 2.5 x 10(-7) mol s(-1); app. K(m) 8.2 x 10(-3) M) and enantioselective production of phenylalanine (32 +/- 4% ee) for reactions conducted in an aqueous buffer system. Substrate selectivity was evident, and a turnover number (k(cat)) of 0.1 s(-)(1) was determined. This is the first example of the catalysis of sigmatropic shifts in aqueous media by molecularly imprinted polymers.

Biomimetic Materials↗
PubMed2002

Effect of using self-etching primer for bonding orthodontic brackets.

Questions over the use of self-etching primers with composite resin adhesives in the bonding of orthodontic brackets remain unsolved. In addition, there are no previous reports on the efficacy of self-etching primers with resin-modified glass ionomer cements for bonding orthodontic brackets in orthodontic dentistry. The purpose of this study was to determine the shear bond strengths of orthodontic brackets bonded with one of four protocols: (1) a composite resin adhesive used with 40% phosphoric acid, (2) the same composite resin used with Megabond self-etching primer, (3) a resin-modified glass ionomer cement adhesive used with 10% polyacrylic acid enamel conditioner, and (4) the same resin-modified glass ionomer cement used with Megabond self-etching primer. The appearance of the tooth surfaces after acid etching or priming was observed with a field-emission scanning electron microscope (FE-SEM). When used with resin-modified glass ionomer cement, Megabond self-etching primer gave no significantly different shear bond strength compared with polyacrylic acid etching. But when used with composite resin adhesive, Megabond self-etching primer gave significantly lower shear bond strength than phosphoric acid etching. However, the shear bond strength of orthodontic brackets bonded with composite resin adhesive after Megabond priming was almost the same as that of brackets bonded with resin-modified glass ionomer cement after polyacrylic acid etching. FE-SEM observation revealed that Megabond self-etching primer produced less dissolution of enamel surface than did phosphoric acid and polyacrylic acid etching. Megabond self-etching primer may be a candidate for bonding orthodontic brackets using the resin-modified glass ionomer cement for minimizing the amount of enamel loss.

Acid Etching, Dental↗
PubMed2005

Bonding durability of using self-etching primer with 4-META/ MMA-TBB resin cement to bond orthodontic brackets.

This study determines the bonding durability when a self-etching primer is used with Superbond C&B (a 4-methacryloxyethyl trimellitate anhydride/methyl methacrylate-tri-n-butyl borane resin) to bond orthodontic brackets to enamel. Thermocycling test was used to assess bonding durability. Metal brackets were bonded to the phosphoric acid-etched or Megabond self-etching primer-treated enamel surface of human premolars using Superbond C&B. The shear bond strengths were measured after immersion in water at 37 degrees C for 24 hours or after 2000 or 5000 cycles of thermocycling between 5 degrees C and 55 degrees C. Data were analyzed using 2-way analysis of variance and Fisher's protected least significant difference test for multiple comparisons. There was no significant difference in shear bond strength between phosphoric acid and Megabond self-etching primer treatment before the thermocycling test. After 2000 and 5000 thermal cycles, significant decreases in shear bond strength were observed with phosphoric acid etching. On the contrary, no significant differences in shear bond strength were observed after 2000 and 5000 thermal cycles with Megabond self-etching primer. The adhesive remnant indices were not significantly different between phosphoric acid etching and Megabond self-etching primer treatment either before or after thermal cycles. This study suggested that when used with Superbond C&B in bonding orthodontic brackets, Megabond self-etching primer is superior to phosphoric acid as an enamel preparation agent in providing durable bond strength.

Acid Etching, Dental↗
PubMed2002

Micro-tensile bond strengths of bonding agents to pulpal floor dentine.

AIM: The purpose of this study was to characterize the dentine surface of the pulpal floor and to determine the micro-tensile bond strengths of two dentine adhesive systems used in conjunction with a resin composite core material to pulpal floor dentine. METHODOLOGY: Thirty-six extracted human molars were cut horizontally with a slow-speed diamond saw to expose the pulp chamber and the pulp tissue was removed. Eight teeth were used to investigate characteristics of untreated and etched dentine surfaces of the pulpal floor using SEM. Twenty-eight teeth were randomly allocated to two groups, each of 14 teeth. In group 1, a 'one-bottle' system (Prime & Bond NT) was used as dentine bonding agent and in group 2, a self-etching-priming system (Clearfil SE Bond) was applied. Pulp chambers of both groups were then filled with resin composite core buildup (FluoroCore) and kept moist in tap water at 37 degrees C for 24 h. Samples were prepared for micro-tensile bond testing by sectioning each tooth vertically in the mid-pulpal floor region and shaped to an hour-glass form of 1 +/- 0.2 mm(2) area at the bonded interface. Micro-tensile bond strengths were determined using a universal testing machine at a crosshead speed of 1 mm min-1. Fractured surfaces were examined by SEM. RESULTS: The intact pulpal floor showed numerous calcospherites with variable tubule density and few accessory canals. Etching the pulpal floor with 34% phosphoric acid gel resulted in an irregular surface with patent dentinal tubules and the dome-shaped calcospherites mostly lost. With self-etching primer, the superficial dentine surface was less demineralized and little peritubular dentine matrix was removed. Mean bond strength for the self-etching-priming (Clearfil SE Bond) specimens was significantly greater than for 'one-bottle' (Prime & Bond NT) specimens (P< 0.05, Student's t-test). The fracture mode of Clearfil SE Bond specimens was mostly partial cohesive failure within dentine, whilst Prime & Bond NT specimens mostly showed partial cohesive failure in bonding resin/composite. CONCLUSIONS: Despite an irregular surface morphology and absence of a smear layer, bonding to pulpal floor dentine was weaker than previously reported for cut coronal dentine. The self-etching-priming system bonded more strongly than the 'one-bottle' system.

Acid Etching, Dental↗
PubMed1999

Five year evaluation of class III composite resin restorations in cavities pre-treated with an oxalic- or a phosphoric acid conditioner.

An oxalic acid solution has been proposed as a conditioning agent for resin composite restorations in two commercial adhesive systems. The durability of 163 class III restorations, including 12 class IV restorations, in cavities pre-treated with an oxalic acid total etch technique or an enamel etch with phosphoric acid was studied. Each of 52 patients received at least one of each of three experimental restorations. The restorations were evaluated yearly with slightly modified United States Public Health Service (USPHS) criteria. After 5 years 95% of the restorations were evaluated as acceptable. Reasons for failure were the fracture of four fillings, including three class IV, secondary caries contiguous to two fillings and a non-acceptable colour match for one restoration. For eight class III restorations a fracture of the incisal tooth structure was registered. No differences were seen between the three experimental restorations.

Acid Etching, Dental↗
PubMed2002

Effect of irrigation solutions on dentin bonding agents and restorative shear bond strength.

STATEMENT OF PROBLEM: The presence of irrigation solution prior to the application of dentin bonding agents may be one source of contamination and may adversely affect bond strength. PURPOSE: The purpose of this in vitro investigation was to evaluate the effect of irrigation solutions of different purity levels on the shear bond strength of a hybrid composite to dentin. MATERIAL AND METHODS: Forty extracted, intact human molars were hand-scaled. All soft tissue was removed, and the teeth were stored in room-temperature tap water for 1 week. Subsequently, each tooth was embedded in autopolymerizing acrylic resin with the coronal portion exposed. After complete polymerization of the resin, the dentin surfaces were exposed, and the crown was cut longitudinally on all 4 sides to produce flat dentin surfaces for bonding. The prepared specimens were assigned to 4 groups of irrigation solutions: tap water (control), sterile water, 0.9% NaCl irrigation solution, and filtered water. Within each irrigation group were 4 dentin bonding agent subgroups: Prime & Bond NT, One-Step, Single Bond Adhesive, and OptiBond Solo. The dentin surfaces (n = 10 per irrigation/bonding agent pair) were etched with 37% phosphoric acid, rinsed with the assigned irrigation solution for 15 seconds, and then dried. Plastic cylinders (3 mm long x 3 mm inner diameter) were filled with a hybrid composite (Herculite XRV) and bonded to the dentin. Specimens were loaded in a universal testing machine, and shear force was applied to the base of the composite cylinders, parallel to the dentin surfaces, at a crosshead speed of 0.05 in/min until fracture. Failure loads were recorded. Bond strength data were compared with analysis of variance (P<.05). Post-hoc comparisons of means were performed with t tests and P values adjusted for multiple comparisons (Bonferroni method). RESULTS: Tap water irrigation (control) produced no significant difference in bond strengths for all dentin bonding agents tested. When other irrigation solutions were used, One-Step consistently produced significantly lower bond strengths than other dentin bonding agents (P<.05). No preferential choice of irrigation solution could be made for Prime & Bond or Single Bond Adhesive. However, when One-Step or Solo was used, irrigation with normal saline significantly reduced bond strengths (P<.05). CONCLUSION: Within the limitations of this study, the bond strength to dentin of a hybrid composite irrigated with different solutions was dependent on the dentin bonding agent used.

Acid Etching, Dental↗
PubMed2003

Comparison of microleakage on one composite etched with phosphoric acid or a combination of phosphoric and hydrofluoric acids and bonded with several different systems.

STATEMENT OF PROBLEM: There are no data available on whether or to what extent hydrofluoric acid affects the marginal integrity of dentin-bonded composite restorations when it is used instead of phosphoric acid in the total-etch technique. PURPOSE: This in vitro study examined the etching effects of phosphoric acid versus a combination of phosphoric and hydrofluoric acid by evaluation of microleakage in a composite restoration bonded with different dentin adhesive systems. MATERIAL AND METHODS: Extracted teeth (n = 90) containing 2 class II preparations, mesial occlusal (MO) and distal occlusal (DO) standarized (cervical margins in dentin) were perfused with Ringer solution and etched in 1 of 2 ways: with phosphoric acid only or with phosphoric combined with hydrofluoric acid. Different dentin bonding agents were then applied (Etch & Prime 3.0, Optibond Solo, Prime & Bond NT, Scotchbond 1, Syntac Single Component, or Syntac Sprint; (n = 15 for each etching material)). The preparations were restored with a hybrid composite (Herculite XRV) and submitted to 5000 thermocycles (5 degrees C to 55 degrees C) to simulate the in vivo situation. Microleakage was assessed with 2% methylene blue diffusion for 24 hours. Dye penetration was calculated as a percentage of the total length of the gingival margins of the preparation with light microscopy at original magnification x 32. The results were analyzed with the Kruskal-Wallis multiple comparison z-value assay (alpha = .05). RESULTS: Differences in dye penetration were significant, both as a function of the dentin adhesive and the conditioning mode applied. In the specimen groups conditioned with phosphoric acid, Optibond Solo (54% +/- 44%) and Syntac Sprint (74% +/- 39%) demonstrated the lowest penetration values. Higher values were obtained for Prime & Bond NT (81% +/- 34%), Scotchbond 1 (83% +/- 31%), Etch & Prime 3.0 (85% +/- 33%), and Syntac Single Component (95% +/- 16%), with no significant differences (alpha=.05) between specimen groups. The best results were obtained for Syntac Sprint (24% +/- 26% dye penetration) after conditioning with a mixture of phosphoric and hydrofluoric acid. The least favorable result was obtained for Optibond Solo (65% +/- 31%). It was significantly different from Prime & Bond NT (76% +/- 37%), Scotchbond 1 (85% +/- 29%), and Etch & Prime 3.0 (88% +/- 24%). Syntac Single Component (75% +/- 32%) was significantly different from Syntac Sprint. Syntac Single Component and Syntac Sprint exhibited significantly better results when conditioned with a combination of phosphoric acid and hydrofluoric acid than with phosphoric acid only. CONCLUSION: Within the limitations of this in vitro study, total-etching water-based (Syntac Single Component) and acetone-based (Syntac Sprint) bonding agents with a combination of phosphoric acid and hydrofluoric acid led to significant reductions (alpha=.05) in dye penetration compared to phosphoric acid conditioning only. Ethanol-based dentin bonding agents (Etch & Prime 3.0, Optibond Solo, and Scotchbond 1) were not significantly influenced by the type of conditioner used.

Acid Etching, Dental↗
PubMed2000

In situ gel formulations for gene delivery: release and myotoxicity studies.

The in vitro release of plasmid DNA and salmon sperm DNA from in situ gel formulations was investigated. Two in situ gel systems were studied: (a) an interpolymeric complex (IPC) of water-soluble polymers polymethacrylic acid (PMA) and polyethylene glycol (PEG) and (b) a hydroxypropylmethylcellulose-carbopol system (H:C). Two-way analysis of variance with replication demonstrated that both gel composition and medium pH influenced significantly the release of plasmid DNA from in situ gel formulations. When the release of both types of DNA was compared, higher release was observed for plasmid DNA compared to genomic salmon sperm DNA. Conformational analysis of the released plasmid DNA showed that DNA was released without degradation, but with remarkable conversion from supercoiled (SC) to open circular (OC). In addition, the tested in situ gel systems demonstrated protection from DNAse I degradation. The myotoxicity of the injectable gelling solutions was assessed by the cumulative release of creatine kinase (CK) over 120 min from the isolated rodent extensor digitorum longus (EDL) muscle. A higher level of cumulative CK was observed for IPC when compared to H:C (2:1). These results demonstrate that the in situ gelling systems can be considered as a valuable injectable controlled-delivery system for pDNA in their role to provide protection from DNAse degradation.

Animals↗
PubMed2001

Bacterial penetration and proliferation in root canal dentinal tubules after applying dentin adhesives in vitro.

Endodontic treatment is aimed at eliminating infection and preventing bacterial regrowth in the root canal and dentinal tubules. In the present study the ability of two dentin adhesives to prevent bacterial penetration and subsequent proliferation in dentinal tubules was evaluated. Cylindrical root specimens prepared from freshly extracted bovine teeth were used in an in vitro model of dentinal tubule infection. After removal of the smear layer the intracanal dentinal tubules of the specimens were acid-etched and treated with either Gluma or EBS. Untreated specimens served as controls. Specimens were infected with Enterococcus faecalis and incubated in Brain Heart Infusion for 21 days. Powder dentin samples obtained from within the canal lumina, using ISO 025 to 033 burs, were examined for the presence of vital bacteria by inoculating on agar plates and counting colony-forming units. A significant difference was found between the experimental groups and the untreated group. After application with Gluma specimens showed the least viable bacteria in dentinal tubules. Data suggested that dentin adhesives reduced bacterial invasion into dentin and therefore have a potential role in endodontic treatment.

Acid Etching, Dental↗
PubMed1979

Studies on the mechanism of haemopoietic stem cell (CFUs) mobilization. A role of the complement system.

A variety of substances can mobilize haemopoietic stem cells (CFUs) into the peripheral blood. In this study the involvement of the complement system in the mobilization process was investigated. Pretreatment of mice with the complement-activating factor of cobra venom (CoF), which lowered the serum C3 levels to 10-25% of the normal value, could completely prevent CFUs mobilization induced by high doses of CoF, endotoxin (ET) from Salmonella typhosa, inulin, zymosan and the proteolytic enzymes proteinase and trypsin. On the other hand, mobilization induced by the polyanions dextran sulphate and the copolymer of polymethacrylic acid and styrene could not be prevented, or at least affected only slightly. There appears to be a relationship between the extent of decomplementation by CoF and the extent of CFUs mobilization induced by ET. The results indicate that certain agents mobilize CFUs via the complement system, whereas other agents induce CFUs mobilization independent of the availability of complement components.

Animals↗