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PubMed1997

The effect of early weaning on dentin formation and dentinal caries in rats.

The effect of early weaning on caries progression, dentin formation, and dentin mineralization was examined in four groups of rats. Two groups received a normal diet and were weaned on day 18 or 21, and another two received a sucrose-rich diet and were weaned on day 18 or 21. At age 35 days the lower molars were sectioned sagittally, and the areas of dentin formation and of the dentinal caries were quantified. The width of the predentin zone was measured from histologically stained sections of maxillary molars. Early weaning reduced dentin formation in the group on the high-sucrose diet only the first days; later this effect was partially caught up with. A high-sucrose diet significantly increased caries frequency and extension of caries lesions compared with a normal diet in both early weaned and normally weaned groups. The effect of early weaning on caries frequency and extension in the high-sucrose group was insignificant compared with the normally weaned group on a high-sucrose diet. The predentin zone was wider in the sucrose groups than in the control groups at the end of the experiment. These results indicate that the effect of sucrose on dentin formation was dependent on the stage of physiologic dentin formation, but early weaning as such did not affect this.

Analysis of Variance↗

PubMedDate not supplied

Morphometric computerized analysis on the dentinal tubules and the collagen fibers in the dentine of human permanent teeth.

A morphometric analysis has been performed on important components of human dentine using an image computerized analyzer. The dentinal tubule diameter and their area percentage were calculated. Moreover the area percentage of the collagen fibers in the dentinal matrix was measured. These parameters have been evaluated in different areas of the coronal and the radicular dentine in permanent teeth. Measurements have been performed on undecalcified and decalcified teeth and on teeth treated with enzymatic digestion to remove the organic non collagen matrix and to evidentiate the collagen fiber network. The values obtained in different areas of the tooth and in samples submitted to different treatments were evaluated by statistical analysis. Dentinal tubule diameter and area percentage significatively decrease from the inner to the peripheral dentine both in the undecalcified teeth as in the decalcified ones and in the samples undergone to enzymatic digestion. The collagen fiber percentage in the organic matrix is significatively lower in the mantle dentine.

Adult↗

PubMedDate not supplied

An in vitro comparison of acid etched vs. nonacid etched dentin bonding agents/composite interfaces over primary dentin.

The purpose of this study was to evaluate acid etchant penetration on dentin bonding agents and its effect on the composite resin bond strength. Forty primary molars were mounted, then the buccal and lingual surfaces were prepared into dentin. The teeth were divided into four groups of 10, and four dentin bonding agents were placed on the buccal and lingual surfaces of exposed dentin, as recommended by the manufacturers. One surface of each tooth was etched randomly for 60 sec with 35% phosphoric acid. A standardized tube of composite resin was placed on each dentin surface and polymerized for 60 sec. The tubes were sheared off with an Instron Testing Machine. The specimens then were sectioned to be examined by a scanning electron microscope (SEM). Results demonstrated shear strengths (kg/cm2) of etched (e) and unetched (u) bonding agents to be: Scotchbond (3M Dental Products, St. Paul, MN) (e) 116.7 +/- 37.7, (u) 116.7 +/- 63.0; Scotchbond 2 (3M Dental Products, St. Paul, MN) (e) 112.0 +/- 40.6, (u) 127.0 +/- 38.7; Gluma (Bayer Dental, Leverkusen, Federal Republic of Germany) (e) 80.1 +/- 21.7, (u) 107.0 +/- 16.6; Bondlite (Kerr Manufacturing Co., Romulus, MI) (e) 53.4 +/- 34.7, (u) 79.1 +/- 26.3. The analysis of variance (ANOVA) demonstrated a statistical significance in variance at the P less than 0.001 level. Scheffe's Test indicated no statistically significant differences between the bond strengths of etched vs. nonetched dentin bonding agents and composite resin. SEM evaluation indicated that the acid etchant penetrated none of the dentin bonding agents.

Acid Etching, Dental↗

PubMed1990

[Study on adhesion mechanism of MMA-TBBO resin to dentin. A model experiment using decalcified dentin].

As a model experiment to understand the mechanism of adhesion of the MMA-TBBO resin to dentin, MMA-TBBO was polymerized using a decalcified dentin sheet treated with aqueous citric acid (CA) solutions of copper fluoride (CF), ferric fluoride (FF), or ferric chloride (FC), which are usually used as treating agents in the bonding of the resin to dentin. The curing time for MMA-TBBO resin was considerably reduced on the decalcified dentin sheet treated with FC-CA, CF-CA or FF-CA at an appropriate concentration. Polymerization of MMA-TBBO resin was accelerated in the presence of a fluoride ion. Molecular weight of PMMA depended on the site of polymerization; PMMA polymerization inside the decalcified dentin sheet gave the highest and that outside gave the lowest molecular weight in the presence of an appropriate amount of ferric or cupric ion. These results suggested that ferric compounds adsorbed to decalcified dentin are involved in the polymerization of MMA and thus will influence the bond strength of the MMA-TBBO resin to dentin.

Acrylic Resins↗

PubMedDate not supplied

Enamel and dentin bond strength and bonding mechanism to dentin of Gluma CPS to primary teeth.

This study evaluated the shear bond strength to enamel and dentin and bonding mechanism to dentin of Gluma CPS bonding system to primary teeth enamel and dentin. Pekafill hybrid composite was used. Ten specimens were immersed in deionized water at 37 degrees C for twenty-four hours and ten other specimens were subjected to a thermocycling procedure (2000 cycles between 5 degrees and 55 degrees C, dwell time fifteen seconds). After water storage or thermocycling, the bonded cylinders were sheared and the bond strength calculated. After debonding, the failure sites of all samples were evaluated microscopically. The data were analyzed with an ANOVA and Student-Newman-Keuls test. In ten other primary molars, the buccal surfaces were ground flat on wet SiC papers to expose peripheral dentin. Cylindrical buttjoint cavities were prepared with a cylindrical diamond bur. The cavities were treated with Gluma CPS and filled with pekafill as described above. After fifteen-minute water storage, filling excess was removed and marginal integrity and bonding mechanism of five restorations was examined with a light microscope. Five other restorations were evaluated after storage in water at 37 degrees C for twenty-four hours. Maximal gap widths and hybrid layer thickness were determined. The results showed that thermocycling did not affect the shear bond strength to enamel or dentin. There was a statistically significant difference (p < 0.05) between the shear bond strength values obtained in enamel and dentin. The maximal gap width was not significantly different between specimens that were stored in water for fifteen minutes or twenty-four hours. The average hybrid layer thickness was 11.7 +/- 1.1 micrograms. All specimens revealed a resin cohesive failure very close to enamel or dentin surface. The etch patterns produced on the abraded enamel surface were uniform and deeper as compared to the sample that was pumiced. This was also confirmed in the epoxy replicas.

Acid Etching, Dental↗

PubMed1993

Bond strengths to superficial, intermediate and deep dentin in vivo with four dentin bonding systems.

The shear bond strength of four dentin bonding systems which remove or modify the smear layer were measured in vivo in dog canine and molar teeth as a function of dentin depth. Dentin bond strengths were higher with cuspid teeth compared to molar teeth. Most bonding systems gave higher bonds to superficial dentin and progressively lower bond strengths deeper dentin. The highest bond strengths were obtained with Clearfil Liner Bond, followed by Superbond C&B, Scotchbond 2 and Tenure. The former two bonding systems achieved shear bond strengths to cuspids that were > 10 MPa regardless of dentin depth while the latter two systems produced bond strengths < 10 MPa. In molars, the same ranking of bonding systems was noted but the value that separated the high from the low bonds was 5 MPa.

Analysis of Variance↗

PubMed2002

Dentin bonding as a function of dentin structure.

The traditional principles of operative dentistry have been challenged since Dr. Buonocore introduced the aid-etch technique in 1955. In spite of the numerous changes in clinical protocols and adhesive techniques, adhesion to dentin remains difficult. The importance of micromechanical bonding to dentin has been recognized over the last decade. Researchers now believe that dentin adhesion relies primarily on the penetration of adhesive monomers into the filigree of collagen fibers left exposed by acid etching. Two main strategies are currently in use for bonding to enamel and dentin: the self-etch technique and the total-etch technique. The efficiency of either bonding strategy depends very much on the dentin substrate used for bonding. Laboratory tests use ideal dentin from extracted teeth, which does not reflect the clinical reality. Clinical studies are the ultimate test for any dental adhesive material.

Clinical Trials as Topic↗

PubMed2003

Dentin permeability: self-etching and one-bottle dentin bonding systems.

STATEMENT OF PROBLEM: There are many bonding systems available, with or without a prior acid etch. The mechanisms differ from system to system. Therefore it is important that the clinician know which are the most effective and which provide the best seal. PURPOSE: This study measured the infiltration of physiological saline solution across dentin after application of self-etching or 1-bottle dentin bonding systems. MATERIALS AND METHODS: Thirty-six extracted noncarious human third molars from patients 18 to 25 years old were used for this study. Dentin disks were cut from crown segments parallel to the occlusal surface at the incisal portion of the pulp cavity. The 36 disks, each 1 mm thick, were divided into 6 groups (n=6 per group), each of which received one of the following dentin bonding systems: Optibond Solo Plus and Excite, which have ethanol as the solvent; Prime & Bond NT, which has acetone as the solvent; Single Bond, which has a mixed solvent; and Clearfil SE Bond or Prompt L-Pop, both self-etching systems The hydraulic conductance, the volume of fluid transported across a known area of surface (0.28 cm(2)) per unit time under a unit pressure gradient (200 cm H(2)O), was analyzed for the self-etching and 1-bottle dentin bonding systems with the Flodec apparatus. Both sides of each specimen were etched with 36% phosphoric acid for 30 seconds. Measurements were made every 30 seconds for 15 minutes. The initial measurement served as the reference value for each specimen. The measurements were repeated when a smear layer had been formed and, finally, after one of the 6 bonding systems had been applied. The data were analyzed by use of analysis of variance and a posteriori tests (Fischer's PLSD, Duncan's new multiple range) with alpha=.05. RESULTS: The greatest mean reduction (40%, P<.05) in penetration was observed with the 4 products with conventional etching: Optibond Solo Plus, Single Bond, Excite, and Prime & Bond NT. The self-etching products were associated with reductions of 36% (Clearfil SE Bond) and 16% (Prompt L Pop). Standard deviations were high, 50% of the mean value, except for the Single Bond group (-42 +/- 13) and Prime & Bond NT (-41 +/- 14). CONCLUSION: Within the limitations of this study, the 4 bonding systems tested with a phosphoric acid before etching provided a greater decrease in dentin permeability than the 2 self-etching systems. The difference in permeability decrease was significant for Prompt L-Pop but not for Clearfil SE Bond.

Acetone↗

PubMed1999

The influence of dentine bonding systems and their handling characteristics on the morphology and micropermeability of the dentine adhesive interface.

OBJECTIVES: Development of an adequate interfacial seal is fundamental to achieving a good dentine bond. This study investigates the influence of the properties and application of primers and resin adhesives on dentine interfacial morphology and micropermeability, using a fluorescence confocal microscopy technique. METHODS: Three commercially available (Optibond, Clearfil Liner Bond 2, Pertac Universal Bond) and four experimental dentine bonding systems based on the total each technique were used in the study. Approximal cavities were prepared in third molar teeth and restored using the dentine bonding system (DBS) and resin composite. In the interfacial morphology study the primer and adhesive bonding system were labelled with fluorescent dyes, while in the micropermeability study the pulp chambers were filled with fluorescent labelled saline for 3 h. Ten teeth were prepared in each study for each dentine bonding system. Teeth were sectioned longitudinally and viewed with a tandem or laser scanning confocal microscope. Interfacial micropermeability from the pulpal wall was measured using image analysis techniques. RESULTS: All primers and adhesives showed good penetration of the prepared dentine, except Pertac Universal Bond which manifested 100% micropermeability. The lowest micropermeability results were obtained with Clearfil Liner Bond 2, Optibond and a total etch experimental system where the primer was applied with agitation and contained no photo-initiators and the adhesive resin was unfilled. The latter, when used with a photosensitive version of the same primer, demonstrated a detrimental effect on micropermeability. Light activation of primers in the experimental systems coincided with very variable patterns of leakage. CONCLUSIONS: This high resolution confocal fluorescence technique enabled both the degree and site of micropermeability within the interfaces to be recorded. Matching of primers and adhesives in DBS is important to minimize micropermeability. The non-polymerized primer system probably retained some elasticity in the hybrid zone and so gave less leakage than experimental primers with photo-initiators.

Dentin↗

PubMed2002

Effects of a potassium nitrate mouthwash on dentinal tubules--a SEM analysis using the dentine disc model.

The concept of tubular occlusion as a method of dentine desensitisation is a logical conclusion from the hydrodynamic hypothesis put forth by Brannström. The aim of this study was therefore to investigate qualitatively by SEM whether a 3% potassium nitrate/0.2% sodium fluoride mouthwash occluded tubule orifices, and by x-ray microanalysis, to characterise the nature of the deposits if any, following application. Following the 'dentine disc model' methodology 1mm thick tooth sections from unerupted molars were obtained. These were treated with the test and control mouthwashes and subjected to scanning electron microscopy. If any deposits were seen, they were to be subjected to elemental analysis using the energy dispersive x-ray analyser. Examination of all the dentine disc surfaces, treated by water (control), active and control mouthwashes demonstrated that none of the treatments, at any of the time intervals, had any visible effect on the dentinal tubule orifices i.e. there was no dentinal tubular occlusion seen. The results suggest that potassium nitrate does not reduce dentinal hypersensitivity, at least by tubule occlusion. This could mean that there is a different mechanism of action, which could not be detected by this in vitro model.

Dentin↗

PubMed1988

Increase of dentin phosphophoryn with dentin formation.

Dentin phosphophoryn was quantified on bovine and rabbit dentin at three developmental stages. Phosphophoryn was extracted from teeth with 0.6M HCl, and quantified as optical density on DEAE-cellulose chromatogram or as phosphoserine content. Bovine phosphophoryn showed progressive increase with formation of dentin. Matrix-associated phosphophoryn was also quantified as phosphoserine content in insoluble dentin residue which was extracted with 6 M urea after decalcification. This fraction increased with formation of dentin both in bovine and rabbit dentin. Phosphophoryn is thought to be related to the later stage of dentin formation.

Animals↗

PubMed1985

Scanning electron microscopic observations of casts of human dentinal tubules along the interface between primary and secondary dentine.

A scanning electron microscope cast technique was used to examine the interface between primary and secondary dentine in young and old human teeth. In addition, more traditional methods were used to examine this interface with light microscopy, identical regions being viewed before and after demineralization. No continuity was seen between the tubules in primary dentine and those in irregular secondary dentine in the scanning electron microscope preparations. These preparations did show the tubules to be continuous between primary dentine and regular secondary dentine in young and old teeth. Both the scanning electron microscopic and light microscopic observations suggested that regular secondary dentine becomes highly sclerosed in old teeth.

Adult↗

PubMed1994

Morphologic aspects of the resin-dentin interdiffusion zone with five different dentin adhesive systems tested in vivo.

The new generation of enamel dentin adhesive materials provides removal of the smear layer, inducing structural changes in the dentinal surface and creating a retentive interdiffusion zone or hybrid layer between the two substrates. Some studies have demonstrated hybrid layer formation in in vitro samples, but few articles have described it in in vivo specimens. The hybrid layer forms in peritubular and intertubular treated dentin and improves adhesion between tooth surface and adhesive resins. This in vivo study investigated the formation of a hybrid layer by use of five different enamel dentin adhesive systems. The dentin adhesives systems were tested on flat dentin preparations made on vestibular surfaces of periodontally compromised teeth. The sample teeth were extracted immediately after the resin was cured. Half of the samples were used to visualize the hybrid layer and the other half to observe the morphology of the resin tags by use of scanning electron microscopy. All the tested products formed a hybrid layer. In many areas of samples of Gluma 2000, Scotchbond Multipurpose, All Bond 2, and Super Bond D Liner systems, characteristic reverse cone-shaped tags were visible. Resin tags produced by Clearfil Liner Bond adhesive were narrower at the apertures of tubules than those of the other four adhesive materials. Morphology of the hybrid layer and of the resin tags of these samples were similar to in vitro samples observed in other studies.

Composite Resins↗

PubMedDate not supplied

Evaluation of the interface between one-bottle bonding agents and dentin by cryopreparation and low-temperature scanning electron microscopy (LTSEM). A pilot study on perfused dentinal samples.

OBJECTIVES: Dentin bonding samples are generally observed in the high vacuum chamber of an electron microscope only after completion of the bonding procedure fixation, dehydration and drying of the specimens. The purpose of this study was to observe the effect of each step in the application of various one-bottle dentin bonding agents (DBA) using cryopreparation followed by low-temperature scanning electron microscopy (LTSEM). METHODS: Prime&Bond 2.1 (P&B 2.1), Coltène Experimental (Exp.) and Syntac Single Component (Syntac SC) were applied onto perfused dentin of extracted, human third permanent molar teeth. After acid-etching, rinsing and drying, and following the application of the respective resins, the teeth were fractured at random and plunge-frozen in liquid nitrogen before examination under LTSEM. As this method preserves the state of the treated surface at the moment when it is frozen, each step of the application of the DBA can be observed as if it were a 'real-time' procedure. RESULTS: Acid-etching the dentin resulted in the removal of the smear layer for all materials tested. Those one-bottle DBAs which recommend the application of two consecutive resin layers (P&B 2.1 and Syntac SC) showed incomplete saturation of the dentinal surface after application of the first layer. With Syntac SC the incomplete saturation was more pronounced than with P&B 2.1. The use of Exp. resulted in a much more homogeneous coverage of the dentin despite only one layer of resin having been applied. CONCLUSION: It is concluded that cryo-preparation followed by LTSEM appears to be a method which allows each stage of the application of DBA to be evaluated.

Acid Etching, Dental↗

PubMed1997

Effect of cleaning dentine with soap and pumice on shear bond strength of dentine-bonding agents.

This in vitro study reports on the cleaning effect of different soaps on the shear bond strength of various dentine-bonding agents. Human teeth were coated with provisional cements for 24 h or for 14 days. After removing the provisional cements with a scaler, the dentinal surface was cleaned with a cotton pellet and non-fluoridated flour of pumice and soap for 10 sec. Different dentine-bonding agents and a luting resin were bonded to the dentinal surface according to manufacturers' instructions with the bonding agent and the composite material being light-cured at the same time. The bonding agents were tested under intrapulpal pressure and with thermal cycling to imitate physiological conditions. Compared with cleaning the dentine with water and pumice, all soaps investigated in this study decreased the shear bond strength values of the tested dentine-bonding agents considerably.

Dental Bonding↗

PubMed2001

Shear bond strength of an autopolymerizing core buildup composite bonded to dentin with 9 dentin adhesive systems.

STATEMENT OF PROBLEM: Clinicians have reported unexpected debonding of autopolymerizing composite core buildups. It has been postulated that dentin adhesive systems that incorporate a combined primer-adhesive may be incompatible with autopolymerizing composites. If so, large numbers of existing restorations may be predestined for early failure. PURPOSE: This in vitro investigation examined the shear bond strength values of an autopolymerizing core buildup composite bonded to dentin with 9 dentin adhesive systems. MATERIAL AND METHODS: Cylinders of the core buildup composite (2.38-mm diameter) were bonded to moist dentin according to the manufacturers' instructions. Specimens were stored in 37 degrees C water for 1 week, thermocycled (5 degrees C to 55 degrees C, 30-second intervals, 1000 cycles), and returned to water storage overnight. Specimens then were debonded with a universal testing machine at 1.0 mm/min, with results recorded in megapascals. Data were statistically analyzed with a Kruskal-Wallis test, with pairwise Wilcoxon rank sum (Mann-Whitney) tests used to determine significant (P<.05) differences between groups. RESULTS: The dentin adhesive systems in order of decreasing median bond strength were Optibond FL > One Step, All-Bond 2, Clearfil SE, Amalgambond Plus > Single Bond, Optibond Solo Plus, Tenure > Scotchbond MP. CONCLUSION: No predictable relationship was found between the general formulation of the dentin adhesive agents and shear bond strength values. Material incompatibilities were judged to be dependent on formulation.

Bisphenol A-Glycidyl Methacrylate↗

PubMed1988

Dentine hypersensitivity. I. Effects produced by the uptake in vitro of metal ions, fluoride and formaldehyde onto dentine.

Dentine has been shown to possess affinity for a large number of varied compounds, many of which have been shown effective in clinical trials, for the treatment of dentine hypersensitivity. The mode of action of these compounds is unclear. The aim of this study was to investigate the uptake of metal ions, fluoride and formaldehyde in solution onto dentine in vitro and determine whether therapeutic effects could be mediated through occlusion of dentinal tubules. Etched dentine sections were exposed for 1 h to 1000 ppm solutions of fluoride and metal salts. Levels of fluoride and respective metals could be extracted and measured from the specimens. Saliva pretreatment had a variable but small effect on uptake of each ion, but post treatment washings reduced all levels of retained fluoride and metals. X-ray microanalysis indicated surface or immediate subsurface deposits of metals. However, surface changes were only consistently produced by zinc and more particularly tin salts. Both zinc and tin salts produced covering or obturation of tubules. The surface effects of zinc could largely be reversed by washing, but not those of tin. Formaldehyde alone or in the presence of saliva produced no effects. A 4-week study involving twice daily exposure of specimens to saliva and fluoride, metals or formaldehyde yielded essentially the same results. It is unlikely that, except for tin, the compounds tested achieve their apparent clinical effects mediated by direct occlusion of dentinal tubules.

Calcium↗

PubMed2002

Comparison of resin-dentine interface in primary and permanent teeth for three different durations of dentine etching.

Hybridization of dentine is identified as a basic bonding mechanism between resin and dentine, hence studying the micro morphology of hybrid layer may explain lower bond strength that has been observed in primary teeth. The aim of the present study was to compare the thickness and micromorphology of Hybrid layer formed in primary and permanent teeth for 3 different durations of dentine etching time (5, 10 and 15 sec) with 10% phosphoric acid as etchant. Thickness and micromorphology of hybrid layer was observed on SEM photographs obtained at 750X. Results indicated that primary teeth presented with a significantly thicker hybrid layer compared to permanent teeth at 10 sec (P<0.05) and 15 sec (P<0.01) of dentine etching. It was concluded that owing to the high reactivity of primary teeth to etchants, the etchants be applied for shorter period on primary dentine compared to permanent dentine for better performance of composite restoration in primary dentition.

Acid Etching, Dental↗