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At least 613 records · Page 34Linked to original sources

PubMed1998

Effect of 10% phosphoric acid conditioning on the efficacy of a dentin bonding system.

The efficacy of a commercial total-etch wet-bonding dentin bonding system and the effect of conditioning using 10% phosphoric acid both on the Ca-content in the substrate dentin and on the efficacy of the experimental contraction gap-free dentin bonding system were evaluated by measuring the wall-to-wall polymerization contraction gap width of a commercial light-activated resin composite filled into a cylindrical cavity prepared in extracted human dentin. The Ca-content in the dentin was measured with an EDS. Complete marginal adaptation was obtained only in the experimental contraction gap-free dentin bonding system group. The Ca-content in the dentin was rapidly reduced by the 10% phosphoric acid conditioning. It was concluded that the dentist should not decalcify the dentin cavity wall possibly by using a dentin conditioner such as 10% phosphoric acid because the resin composite paste is apt to separate easily from the decalcified dentin cavity wall during polymerization.

Acid Etching, Dental↗

PubMedDate not supplied

Effect of saliva contamination on the bond of dentin to resin-modified glass-ionomer cement.

This in vitro study compared the shear bond strength of a resin-modified glass-ionomer restorative material (Fuji II LC) bonded to saliva-contaminated dentin versus non-contaminated dentin. Seventy-five extracted human molar teeth were randomly divided into five groups of 15 samples each. The dentin was treated with 10% polyacrylic acid for 20 seconds, rinsed, and dried. The acid-treated dentin surfaces in Groups 1-4 were contaminated with saliva. In Group 1, the saliva was air thinned. In Groups 2-4, saliva was dried completely with compressed air. The saliva-contaminated dentin in Group 3 was rinsed and dried. The saliva-contaminated dentin in Group 4 was rinsed, dried, treated with 10% polyacrylic acid, and dried. Specimens in Group 5 received no contamination. The resin-modified glass-ionomer cement restorative material was mixed and applied to the dentin surfaces. Following placement of the restorative material and 7 days of storage, the specimens were thermo-cycled 300 times. Using the Instron Universal Testing Machine, a shear force was applied to the restorative material. Shear bond strength values were compared among the groups using a one-way ANOVA and Student-Neuman-Keuls Multiple Range Test (alpha = 0.05). The non-contaminated specimens (Group 5) were significantly stronger than the contaminated specimens (Groups 1-4). There were no significant differences in bond strength among the groups containing contaminated specimens. Salivary contamination occurring after dentin etching significantly reduced the bond strength of the resin-modified glass-ionomer restorative material to dentin. Neither rinsing nor rinsing and re-etching resulted in bond strengths as great as to non-contaminated dentin.

Analysis of Variance↗

PubMed2000

Influence of different acid conditioners on the tensile bond strength of 4-META/MMA-TBB resin to Er:YAG laser-irradiated bovine dentin.

PURPOSE: This study evaluated the effect of acid conditioners on resin bonding to dentin following irradiation with an Er:YAG laser and investigated the characteristics of resin bonding to the laser-treated dentin. MATERIALS AND METHODS: Extracted bovine teeth were cervically sectioned to expose a dentin surface. After polishing, the dentin was irradiated with an Er:YAG laser. Aqueous solutions of 10% citric acid (10-0) or 10% citric acid/3% ferric chloride (10-3) were then applied to the laser-treated surface as acid conditioners. After the acid treatment, a PMMA rod was bonded to the irradiated dentin using 4-META/MMA-TBB resin, and miniaturized dumbbell-shaped bonded specimens were prepared. These specimens were subjected to tensile testing, and fractured surfaces were observed with field-emission scanning electron microscopy (FE-SEM) to determine the mode of fracture. Additionally, the resin-dentin interfaces were observed under FE-SEM. RESULTS: The tensile bond strength of acid-conditioned bonded specimens was lower than that of specimens not subjected to acid treatment (11.1 MPa) in the laser-irradiated group. No significant difference was observed between 10-0 and 10-3 treatments. 10-3 treatment yielded the highest bond strength (24.6 MPa) in the nonirradiated group, as opposed to only 7.7 MPa in the laser-treated group. Cohesive failure in the dentin was observed in almost all specimens in the irradiated group. Furthermore, a 10- to 30-micron-thick resin-penetrated layer was observed at the interface between the dentin and resin. CONCLUSION: These results suggest that the effect of acid conditioners on resin bonding to dentin differs according to whether the dentin has been laser irradiated or not.

Acid Etching, Dental↗

PubMed2001

Influence of self-etching primer on the resin adhesion to enamel and dentin.

PURPOSE: To evaluate the shear bond strength of resin-based composite to dentin and enamel using three adhesive systems, two of them containing self-etchant primers. Wettability (contact angle measurements) of the primers of these three adhesive systems was also evaluated on superficial and deep dentin. MATERIAL AND METHODS: Contact angle measurements were performed on 30 caries-free extracted human third molars; specimens were sectioned parallel to the occlusal surface to expose superficial and deep dentin. Dentin was ground flat (600-grit SiC) under water to provide uniform surfaces. Contact angle measurements were performed to assess wettability using the Axisymmetric Drop Shape Analysis technique. In order to test the enamel bond strength, 30 extracted bovine incisors were embedded in acrylic resin and ground flat to 800-grit. The adhesives and composite resins were applied following the manufacturers' instructions. All the specimens were stored in water for 24 hrs at 37 degrees C and thermocycled (500x). Shear bond strengths were determined using a universal testing machine and the Watanabe device. For dentin bond strength testing, superficial and deep dentin was exposed in 60 third molars, by sectioning the occlusal surface immediately under the enamel-dentin junction or close to the pulp chamber. After grinding (500 grit SiC), the dentin surfaces were assigned to three groups: (1) Clearfil SE Bond (CSEB)/Clearfil AP-X resin composite. (2) Etch & Prime (E&P)/Degufill mineral resin composite. (3) Scotchbond Multi-Purpose Plus (SBMP)/Z100 resin composite. RESULTS: One-way ANOVA and Student-Newman-Keuls multiple comparisons tests showed that no differences were found between contact angles on superficial and deep dentin. CSEB and E&P, without significant differences between them, had greater mean contact angle than SBMP. On enamel, Etch & Prime resulted in the lowest bond strength, but no significant differences existed with Scotchbond Multi-Purpose were found. On dentin, Clearfil SE Bond resulted in the significantly highest bond strength; no significant differences exist between Etch & Prime and Scotchbond Multi-Purpose.

Acid Etching, Dental↗

PubMed2003

Interfacial micromorphology of three adhesive systems created in caries-affected dentin.

PURPOSE: To investigate the morphology of the resin-dentin interface of three dentin adhesive systems (One Coat Bond, Clearfil SE Bond and One-Up Bond F) bonded to caries-affected dentin, exposed using either rotary instrumentation in conjunction with a caries detector dye or a chemo-mechanical caries removal system (Carisolv). MATERIALS AND METHODS: 60 extracted human molars with occlusal caries were used. 30 teeth had carious dentin removed using slow-speed round steel burs after staining with the caries detector dye, and carious dentin from the remaining teeth was removed using Carisolv. The teeth from each caries removal technique were randomly divided into three groups, bonded with one of the three adhesive systems above according to the manufacturers' instructions, and a thin layer of resin-based composite applied. The teeth were sectioned parallel to the bonded surface to obtain a 3 mm thick bonded dentin disc. The specimens were assigned to one of two observation techniques: a fracture technique or an acid-base technique. Fracture technique: a shallow groove was prepared across the dentin surface of the specimen, fixed in 10% buffered formalin, dehydrated in an ascending ethanol series up to 100%, critical-point dried, and fractured along the prepared groove. Acid-base technique: the specimens were sectioned vertically across the bonded interface, fixed in 10% phosphate buffered formalin, polished with diamond paste down to 0.25-microm particle size, immersed in 10% orthophosphoric acid for 3-5 s and 5% sodium hypochlorite for 10 min. All specimens were gold sputter-coated and observed using FE-SEM. RESULTS: All groups showed hybrid layer formation. However, the thickness varied depending on the adhesive system and the carious dentin removal technique used. One Coat Bond (a "one-bottle" system) showed the thickest hybrid layer (approximately 2 microm) in acid/base treated specimens when bonded to caries-affected dentin, whereas One-Up Bond F (an "all-in-one" system) bonded to normal dentin exhibited the thinnest hybrid layer (approximately 0.3 microm).

Composite Resins↗

PubMedDate not supplied

Bond strengths of Dyract AP compomer material to dentin of permanent and primary molars: phosphoric acid versus non-rinse conditioner.

PURPOSE: The purpose of this in vitro study was to determine the shear bond strengths (SBS) of Non-Rinse Conditioner (NRC, Dentsply) combined with Prime & Bond NT (PBNT, Dentsply), a 1-bottle adhesive. The null hypothesis tested was that the use of NRC with PBNT would not result in SBS different from those obtained with conventional phosphoric acid (PA) etching and bonding application to permanent and primary dentin. METHODS: Extracted human third molars and primary molars were mounted length-wise in acrylic resin. The occlusal surfaces were ground to expose a flat dentin surface, and then polished to 600 grit silicon carbide paper to create smear layers similar to those created with high-speed burs. The teeth were randomly assigned to 4 groups (N = 10) according to the etchant/conditioner (PA vs NRC) and dentin (permanent vs primary) used: (Group I: permanent dentin, PA, PBNT; Group II: primary dentin, PA, PBNT; Group III: permanent dentin, NRC, PBNT; Group IV: primary dentin, NRC, PBNT). Specimens were then secured in a split mold, having a 5 mm diameter opening and a polyacid-modified resin composite (Dyract AP, Dentsply) were inserted and light cured incrementally onto the treated dentin surfaces. All specimens were stored in water for 24 hours prior to shear strength testing using a Franell testing machine at a crosshead speed of 0.8 mm/minute. RESULTS: The mean dentin SBS values (MPa) for the groups were: Group I (13.32 +/- 6.6); Group II (15.21 +/- 5.25); Group III (8.87 +/- 3.12); and Group IV (7.42 +/- 2.98). Analysis of variance and Duncan's multiple range tests indicated significant differences among groups at P < 0.05. CONCLUSIONS: In general, the SBS were remarkably greater in the 2 groups etched with PA in comparison with the 2 groups conditioned with NRC. However, the type of dentin tissue did not influence SBS.

Acid Etching, Dental↗

PubMedDate not supplied

Bond strength and SEM observation of CO2 laser irradiated dentin, bonded with simplified-step adhesives.

This study investigated, mechanically and morphologically, whether the dentin surface irradiated by CO2 laser could be a possible adherent when bonded with simplified-step adhesives. Buccal enamel and cementum of extracted human premolars were removed to expose a flat dentin surface. The dentin surfaces were irradiated continuously with CO2 laser at 1.0 W. Before bonding with either a single-bottle adhesive (Single Bond) or a self-etching priming system (Mega Bond), the irradiated dentin surface was treated as follows: no treatment, NaHCO3 powder abrasion and wet-grinding with 600-grit SiC paper. The treated dentin surfaces were bonded to resin composite with either of the two adhesives. Non-irradiated dentin surfaces were also used as control. Resin bonded specimens were stored in water at 37 degrees C for 24 hours and subjected to microtensile bond test. Additionally, to observe the resin/irradiated dentin interface, resin-bonded specimens were similarly prepared, sectioned into slabs, embedded in epoxy resin, polished with diamond pastes, sputter coated Au-Pd and examined with scanning electron microscopy (SEM). After SEM observation, the specimens were further polished with diamond paste to remove the Au-Pd sputter-coat, immersed in HCL and NaOCl and finally observed by SEM again. In the presence of carbonized dentin, microtensile bond strength drastically decreased but recovered to the control value by removing the carbonized dentin layer visually with SiC paper for both adhesive systems. However, the laser-affected dentin that remained on the bonded interface was easily dissolved with NaOCl and HCl.

Air Abrasion, Dental↗

PubMed2005

Bonding of resin to artificially carious dentin.

PURPOSE: To evaluate the bond strength of adhesive resins to artificially carious dentin specimens which were previously exposed to an acid buffer solution for various periods. MATERIALS AND METHODS: Flat dentin disks were obtained from superficial occlusal dentin of extracted human third molars and polished with wet silicon carbide paper. Dentin disks were immersed in acid buffer solution for different periods to create the demineralized dentin layer. The first group of demineralized specimens was used for the evaluation of demineralization depth under SEM and the second group was used for the bond strength measurement. Shear bond strengths mediated by three dentin adhesives (Clearfil SE Bond, OptiBond Solo Plus Total-Etch, and OptiBond Solo Plus Self-Etch) were examined. A 0.75-mm-diameter area of dentin was bonded according to the manufacturers' instructions before placing a 0.5-mm-high resin composite cylinder. The bonds were stressed in shear at a crosshead speed of 1 mm/min. All data were analyzed using ANOVA and LSD multiple comparison test. RESULTS: Depth of demineralization increased with the prolongation of demineralizing time. After dentin specimens were demineralized for up to 24 h, bond strengths of the self-etching adhesives were significantly higher than those of the total-etch adhesive. However, for longer demineralization periods, no statistical differences in bond strengths were observed. SEM photographs showed that resins cannot thoroughly infiltrate through the whole depth of the demineralized dentin layer. CONCLUSION: Bond strengths to demineralized, artificially carious dentin were affected by the depth of demineralization and adhesive resins used.

Adhesives↗

PubMed2005

Evaluating a method of artificially hypermineralizing dentin to simulate natural conditions in bonding studies.

PURPOSE: This study tested an in vitro model of dentin hypermineralization, aiming to simulate naturally hypermineralized dentin for bond strength studies. The effect on bond strength of a double-etching treatment on the artificially hypermineralized substrate was also evaluated. MATERIALS AND METHODS: Extracted human third molars were selected and 2 groups were formed: a group of 3 teeth, called N (normal dentin) and a group of 6 teeth, called H (hypermineralized dentin). Occlusal surfaces were ground flat to expose midcoronal dentin. Group H was subjected to artificial hypermineralization and subdivided into 2 subgroups: Ht and Hd. The exposed dentinal surfaces of group N and subgroup Ht were etched with 37% phosphoric acid for 15 s prior to bonding with Single Bond adhesive. Dentin of the subgroup Hd was etched twice (double etching) prior to bonding with Single Bond. A 4-mm-high Z100 composite buildup was created on each tooth and, after 24 h water storage, bond strengths were evaluated by the microtensile method. The data between group N and subgroup Ht and between subgroups Ht and Hd were compared using the Student's t test (alpha = 0.05). RESULTS: No significant difference was observed between bond strengths of group N and subgroup Ht (p = 0.108). Subgroup Hd was statistically different from Ht (p < 0.0001). CONCLUSIONS: Bond strengths of Single Bond to artificially hypermineralized dentin did not differ statistically from those to normal dentin substrate. The double etching approach significantly reduced bond strengths of artificially hypermineralized dentin.

Acid Etching, Dental↗

PubMed2006

Effect of different bonding conditions on the shear bond strength of two compomers to bovine dentin.

AIM: Despite the improvements to compomer materials, the bond strength of these materials remains inferior to "composite/resin bonding" systems and limits their clinical use. The purpose of this study was to evaluate the effect of acidic conditioning with phosphoric acid and Prompt L-Pop (PLP) on the shear bond strength of two compomers Dyract AP (DAP) and Composan Glass (CG) to dentin. METHODS AND MATERIALS: Sixty extracted bovine teeth were used to test the shear bond strength of two compomers to flat dentin labial surfaces. The dentin specimens were randomly assigned to six groups of ten specimens each: Group 1: DAP and Prime & Bond NT (PBNT); Group 2: DAP/PBNT with a 15 second dentin etch prior to bonding; Group 3: DAP placed with PLP adhesive; Group 4: CG and Compobond NE (CBNE); Group 5: CG/CBNE with a 15 second dentin etch; and Group 6: CG placed with PLP adhesive. The specimens were stored at 37 masculineC with 100% humidity for 24 hours then mounted and sheared using an Instron Universal Testing Machine at a cross head speed of 0.5 mm/min. The results were recorded in Mega Pascals (MPa). The sheared specimens were examined under a light microscope, and the type of failure (adhesive, cohesive, or mixed) was recorded. RESULTS: The mean dentin shear bond strength value (MPa) for the groups was: Group 1 (11.6+/-3.9); Group 2 (13.2+/-3.3); Group 3 (12.4+/-2.0); Group 4 (13.0+/-4.3); Group 5 (19.3+/-3.7); and Group 6 (13.1+/-3.0). One way analysis of variance (ANOVA) and Tukey HSD post-hoc tests detected a significantly higher bond strength (P = 0.003) for group 5. For groups 1, 3, 4, and 6, the mode of failure was mostly adhesive. When acid etching of dentin was performed (groups 2 and 5), cohesive fracture within dentin was the predominant mode of failure. Acid etching and the use of PLP significantly reduced the number of adhesive fractures and reduced variability in the shear bond strength results. CONCLUSIONS: Acid etching significantly increased the shear bond strength of CG to dentin but did not affect DAP. The application of PLP resulted in a shear bond strength not statistically different from PBNT or CPNE. CG bond to dentin is improved with acid etching using phosphoric acid. However, PLP provided no significant improvement in the shear bond strength of DAP and CG.

Acid Etching, Dental↗

PubMed1990

[Gypsum temporary filling material containing HY-agent. The effects of the HY-agent on the dentin].

The effects of the Tannin-Fluoride preparation, called the HY-agent, on dentin substrate were examined by immersion of the dentin previously treated with HY-agent into the calcifying fluid at 37 degrees C. The changes in the nature of the dentin surface and penetration of elements in the dentin were observed. CaF2 was formed on the dentin as a result of a reaction between F, an element of the HY-agent, and Ca which precipitated from the calcifying fluid. This observation was confirmed by means of the X-ray diffraction method. Penetration of F, Zn, Sr and Ca into dentin was confirmed by the use of an electron probe X-ray microanalyser (EPMA). Application of the HY-agent to the dentin for sevendays increased the hardness of the dentin about 10%. Application of the HY-agent to the dentin for sevendays increased the contact angle about 3%. These results suggested that the organic and inorganic matter in dentin can be stabilized effectively both chemically and physically by treatment with an HY-agent.

Calcium Sulfate↗

PubMedDate not supplied

[Microbial permeability of dentin].

This is a review of the literature about the contemporary aspects of microbial permeability of dentin. They are discussed the factors that are responsible for this question and analytically: the structure of dentin, the composition of dentin in organic and inorganic ingredients, the response mechanisms of dentin, that is the irritation dentin and sclerotic dentin, the hypermineralized zone under carious lesions, the role of saliva and dentinal fluid, the role of pulp and its microcirculation against the invasion of microbes and, the role of smear layer. Also this article refers to the immunological reaction of the pulp and finally to the role of dentist in the permeability of dentin, because the more conservative is a tooth preparation the less is the permeability of dentin. In conclusion, the microbial permeability of dentin is a very complicated biological phenomenon that needs more study and further investigations.

Dental Pulp↗

PubMed1995

Effect of dentin moisture and storage time on resin bonding.

PURPOSE: To evaluate the effects of dentin moisture and two different storage times on the shear bond strength of resin composite bonded to dentin with Scotchbond Multi-Purpose Adhesive. MATERIALS AND METHODS: The occlusal surfaces of 60 extracted human molars were reduced to provide flat dentin surfaces. After being hand-finished using wet 400- and 600-grit SiC papers, the teeth were randomly divided into four groups of 15 specimens each. The teeth were etched, rinsed, and then either blotted with gauze which left a visibly moist surface or dried with compressed air. The primer and adhesive were applied according to the manufacturer's instructions and resin composite cylinders were bonded to the teeth. Two of the groups (one moist, one dry) were stored for 24 hours in 37 degrees C distilled water while the other two groups were stored for 90 days in 37 degrees C distilled water. At the end of their storage times, the specimens were loaded to failure in shear at 0.5 mm/minute. RESULTS: Mean bond strength values and standard deviations in MPa were: Dry dentin at 24 hrs, 13.30 +/- 5.1; Dry dentin at 90 days, 13.07 +/- 3.8; Moist dentin at 24 hours, 13.64 +/- 4.9; Moist dentin at 90 days, 15.58 +/- 5.3. No statistically significant differences were found for bond strengths to dry and to moist dentin for either storage time. Time had no significant effect for either the dry dentin group or the moist dentin group.

Absorption↗

PubMed1996

The quantification of tertiary dentine formation in response to materials commonly placed in deep cavities in general practice in the UK.

PURPOSE OF STUDY: To determine the rate of formation of tertiary dentine in dogs' teeth, in response to five commonly used lining materials. Also, to record the resulting differences in quality of the formed dentine. MATERIALS AND METHODS: Representatives of five types of materials commonly used in general practice in the UK were placed in deep standardised cavities with a remaining dentine thickness of 400-500 microns, and sealed to the cavo-surface with zinc oxide-eugenol. The daily rate of tertiary dentine formed in response to each material was measured over a period of 119 days using a tetracycline staining method. A concomitant study to show the quality of the formed dentine was undertaken using the same materials and experimental conditions. RESULTS: There was a significant difference between the rates of tertiary dentine formation for all materials except zinc oxide-eugenol and Ledermix paste. For each material there was a increased rate of tertiary dentine formation in the second period (29-49 days) compared to the first period (0-28 days). This is considered to be due, in part, to a lag period when damaged odontoblasts are differentiating from mesenchymal elements. The rate of tertiary dentine formation in response to all the test materials was always greater than that of normal physiological dentine formation in unprepared teeth. Qualitatively, there was difference in the formed tertiary dentine beneath each material. All the materials caused odontoblast destruction, altered ground substance production and alterations in the calcification process. CONCLUSION: None of the materials routinely used at present can be considered to be 'ideal' as odontoblast destruction, altered ground substance production and altered calcification occur beneath zinc oxide-eugenol preparations, calcium hydroxide preparations as well as in response to corticosteroid-containing materials such as Ledermix paste and cement.

Analysis of Variance↗

PubMed1997

Resin bond strength with different methods to remove excess water from the dentin.

PURPOSE: To compare the resin bond strength using different methods to remove the excess water from the dentin while maintaining it moist. MATERIALS AND METHODS: 60 human molars were randomly divided into four treatment groups of 15 teeth each as follows: Group 1: A wet bonding technique was used as recommended by the manufacturer and was used as a control group. The exposed occlusal dentin surfaces were conditioned with 32% phosphoric acid (Uni-Etch) for 15 seconds and rinsed for 15 seconds. 40 microL of distilled water was added to standardize the content of the water on dentin surface. The conditioned dentin surfaces were gently blow-dried for 3 seconds with oil-free compressed air. The tip of the syringe was placed at 2 cm from the dentin surface. One coat of the One-Step primer/adhesive was applied to the dentin surface using a fully saturated brush tip, allowed to remain on the surface undisturbed for 3 seconds, and then gently air-dried for 3 seconds from a distance of 1 cm to remove excess solvent and water. A second coat of the primer/adhesive was applied and gently air-dried from a distance of 1 cm. The primer/adhesive was light-cured for 10 seconds. Resin composite (Z100, shade A3) was then polymerized for 40 seconds. Group 2: The dentin surface was blot-dried by applying tissue paper (Kimwipes EX-L) adjacent to the exposed area; Group 3: The excess water on the dentin surface was removed using an applicator brush (Bend-a-Brush) for 5 seconds; Group 4: A small dry hydrophilic cotton pellet was gently applied over the dentin surface to remove the excess water. The sequential steps for these three groups were similar to those of Group 1. The dentin surface remained visibly moist in all procedures. After light-curing, the specimens were thermocycled (5 degrees and 55 degrees C, 500 cycles, 30-second dwell time). The specimens were sheared and the data were analyzed using ANOVA and Tukey's test methods. The site of failure was analyzed using a stereomicroscope and a scanning electron microscope. RESULTS: ANOVA revealed that there was a statistically significant difference between the groups (P < 0.05). Turkey's test revealed that Group 1 was significantly lower than Groups 2, 3 and 4 with no difference between the last three groups (P < 0.05). All samples showed resin cohesive failures.

Analysis of Variance↗

PubMed2005

Effect of desensitizing agents on the hydraulic conductance of human dentin subjected to different surface pre-treatments--an in vitro study.

OBJECTIVES: The aim of this study was to evaluate the variation of fluid filtration across dentin treated with different formulations of potassium oxalate gels and one gel of acidified sodium fluorophosphate, under five different pre-conditioned dentin surfaces. METHODS: The methodology used for the measurement of hydraulic conductance of dentin in the present study was based on the model suggested by Pashley, Stewart and Galloway [Arch Oral Biol 29 (1984)379]. Two hundred dentin discs 1 mm in thickness, obtained from human extracted third molars, were divided into 20 groups of ten specimens each. The groups corresponded to the following experimental materials: 3% potassium oxalate gel-pH 4; 6% potassium oxalate gel-pH 4; 3% potassium oxalate gel-pH 2.5 and 1.23% fluoride gel (APF gel)-pH 3.6-3.9, applied to dentin under the following surface conditions: air-dried, blot-dried, wet, EDTA air-dried; EDTA blot-dried. General MANOVA and post-hoc Duncan tests were performed on the data. RESULTS: Regardless of surface pre-treatment the 3% potassium oxalate gel-pH 2.5 produced the greatest reduction in dentinal filtration (p<0.05) even after citric acid challenge. In general, air-drying the dentin was the best surface pre-treatment (p<0.05). The interaction between the material and surface pre-treatment showed values of hydraulic conductance similar for most of the combinations, but the 3% potassium oxalate gel-pH 2.5 under wet conditions produced the largest reduction in hydraulic conductance. The APF gel produced the smallest reduction in hydraulic conductance when compared with the other materials, regardless of surface pre-treatment. SIGNIFICANCE: the potassium oxalate gels studied in this investigation have a great potential for tubule occlusion and, consequently, should be effective treatments of dentinal hypersensitivity, regardless of dentin wetness.

Acidulated Phosphate Fluoride↗

PubMed1998

Effects of desensitizing agents on human dentin permeability.

PURPOSE: To compare the in vitro effects of three desensitizing agents on hydraulic conductance of human dentin: Protect (n = 10), Gluma Desensitizer (n = 10), MS Coat (n = 10) (Pain-Free in the USA). MATERIALS AND METHODS: Dentin discs were prepared from 40 freshly extracted normal human third molars. The pulpal side of the dentin discs was etched with 37% phosphoric acid for 15 s and then rinsed under tap water. The coronal side was sequentially ground and the dentin discs were sonicated for 30 min. The hydraulic conductance was measured filtering 20% serum in phosphate buffered saline under a pressure of 15 cm H2O. The hydraulic conductance of each dentin specimen was measured before using the desensitizing agent and this value was designated as 100%. Thirty dentin discs were treated, the hydraulic conductance was remeasured and expressed as a percentage of the hydraulic conductance of that specimen before treatment. The teeth were stored for 1 month at 37 degrees C in deionized water and the hydraulic conductance of the 40 dentin discs was recorded again. Ten dentin discs were left untreated to serve as a control. RESULTS: No statistical difference was found between the immediate hydraulic conductance of the three groups after treatment. After 1-month storage, the control group showed a statistically higher hydraulic conductance than the three treated groups. There was no statistical difference between the three dentin desensitizing agents evaluated.

Acid Etching, Dental↗

PubMed1988

Difference in noncollagenous matrix composition between crown and root dentin of bovine incisor.

A comparative study of the organic matrix in crown dentin and root dentin of the bovine incisor has been performed utilizing biochemical analyses and histochemical stainings. Root dentin contained only half the amount of dentin phosphophoryn present in crown dentin. Composition of noncollagenous matrix other than phosphophoryn was also suggested to be different between crown and root dentin. These data indicate that odontoblasts forming root dentin may secrete a noncollagenous matrix having a composition different from that of crown dentin, and that crown and root dentin may be separate in nature. The distinct compositions of noncollagenous matrix may reflect the difference in the mineralization process between crown and root dentin.

Animals↗