Bonding of restorative resins to dentin by means of methacryloylchloride and methacryloyl-R-isocyanate

Abstract – The bonding of restorative resins to dentin by means of an intermediary monomer containing a carboxylic acid chloride or an isocyanate group was investigated. Such intermediary monomers are supposed to react with the organic constituent of dentin. Bond strengths were enhanced by the use of the intermediary monomers, resulting in mean bond strengths of 0.13 kg/mm2. Bond strengths of this order of size are probably too low to be of clinical interest.     

Formaldehyde as bonding agent between dentin and restorative resins

Abstract – The bonding of restorative resins to dentin by means of formaldehyde used in conjunction with an OH-containing monomer as intermediary was investigated. In this way a bonding to the organic constituent of dentin is conceivable. Mean bond strengths of 0.6 kg/mm² were obtained. Bond strengths of this order of size may be of clinical interest.     

Adhesion to dentin by means of Gluma resin

Abstract – In its present version, the Gluma system for bonding restorative resin to dentin involves the application of an enamel bonding agent prior to the composite resin. Conceivably, pretreating the dentin with solutions of amino acids, and incorporating camphorquinone and selected methacrylic monomers into the Gluma adhesive would nullify the need for the enamel bonding agent. A bond strength to dentin of 13.4 MPa was obtained in the control experiment. Using a solution of pyruvic acid and glycine as pretreatment, and an optimized adhesive mixture containing glutaraldehyde, HEMA, BIS-GMA, camphorquinone, and water, bond strengths to dentin of 14.5 MPa and to enamel of 23.3 MPa were obtained. Thus, the new Gluma bonding system gave acceptable bond strengths without the prior application of enamel bonding agents.     

Influence of endodontic materials on the bonding of glass ionomer cement to dentin

Abstract We assessed the bond strength of a glass ionomer cement to dentin that had been in contact with different materials. Flat dentin surfaces in freshly extracted human teeth were covered for 48 h with a 1 mm layer of a variety of materials that are used for temporary filling or root canal sealing. The products were mechanically removed and a glass ionomer cement cylindrical specimen bonded to the dentin surface. After 7-days immersion in 37° C water the tensile bond strength was tested. The results were compared with those on dentin surfaces not in contact with any endodontic material. The statistical analysis showed that none of the materials used interfered with the bonding of the glass ionomer to dentin.     

Adhesion to dentin mediated by Gluma: effect of pretreatment with various amino acids

Abstract – Dentin surfaces were treated with various amino acids. The treatment caused an alteration of the dentin surface that influenced the tensile bond strength to a restorative resin obtained with the Giuma system. The bond strengths varied between 5.6 and 14.2 MPa. Among the amino acids tested, N-phenylglycine produced the strongest bonds.     

Long-term retention of TiF4 and SnF2 after topical application to dentin in dogs

Abstract – As part of an evaluation of the potential of topical application of TiF₄ in the prevention or arrest of root caries, the longevity of the titanium-rich glaze and the long-term retention of titanium and fluoride in exposed dentin surfaces were examined in dogs. For comparison, the effect of fluoride in combination with another cation, tin, was studied as well. Facets of exposed dentin were prepared in two beagles and treated for 1 or 4 min with either a TiF₄ or an SnF₂ solution (1.1 M F, native pH). After 3, 7, or 21 wk, the experimental surfaces were analyzed for fluoride, titanium, tin, and calcium using an electron microprobe. Dentin surfaces treated with TiF₄ for 1 min showed fluoride concentrations ranging from less than 0.15% to 1.03%, while those treated for 4 min with SnF₂ showed values from 0.22% to 1.28%. The calcium analyses revealed partial surface demineralization in one half of the SnF₂-treated specimens, while this was a rare finding in the TiF₄ group. The findings show that a brief application of TiF₄ to exposed dentin results in approximately the same increase in fluoride content as a 4-min application of SnF₂, with, however, less surface demineralization. In addition, the presence of a surface glaze may impart an added benefit to the use of TiF₄ as a topical agent in the prevention of root caries.     

Resin bonding to enamel and dentin with one–component UDMA/HEMA adhesives

The aim of this study was to investigate the potential of UDMA/HEMA mixtures as priming and sealing components of dental adhesives. The monomers were mixed in weight ratios 100/0, 80/20, 60740, 50/50, 40/60, 20/80, 10/90, and 0/100, light activated, and dissolved in acetone at equal parts. The 60/40 UDMA/HEMA mixture served as a reference which was modified with 5, 10, 20, and 30 parts 4-MET relative to the mass of the basic monomer mixture. Shear bond strengths (24 h) of resin composite cylinders, bonded with the adhesive monomers on human enamel and dentin, were determined following a total etch technique with phosphoric acid and application of the adhesives in 2 coats on moist tooth surfaces. Average bond strength to enamel was 32 MPa with no difference between the adhesives. On dentin, significantly different bond strengths were found between UDMA (12.9 MPA) and HEMA (19.4 MPa), whereas all binary mixtures bond strengths were not significantly different (mean 16.2 MPa). Addition of 5 to 20 wt% 4-MET resulted in a significantly increased mean shear bond strength of 22.3 MPa on dentin. At 10%, a maximum mean strength of 25.4 MPa was recorded. It is concluded that mixtures of commonly used polymerizable monomers, characterized by hydrophilic moieties and dissolved in acetone, are promising candidates for effective resin bonding to enamel and dentin, provided application by the moist bonding technique.     

Adhesion of a glass ionomer cement to bleached and unbleached bovine dentin

Abstract Cylinders of Fuji Type II glass ionomer restorative cement were bonded to the superficial dentin layer of young bovine incisor teeth that had previously been subjected to 4 different treatments: 1) teeth immersed in 35% hydrogen peroxide for 60 min and etched with 37% phosphoric acid gel for 60 s; 2) teeth immersed in saline for 60 min and etched with 37% phosphoric acid for 60 s; 3) teeth etched with 37% phosphoric acid for 60 s and immersed in 35% hydrogen peroxide for 60 min; or 4) teeth etched with 37% phosphoric acid for 60 s and immersed in saline for 60 min. Specimens were stored in water at 37° for 1 and 7 days, prior to tension and shear testing. A total of 128 teeth were tested: 8 teeth in each group for each day and for each test. Statistical analysis of the results indicated that there was a highly significant reduction in bond strength of the cement when dentin was exposed to hydrogen peroxide as compared with saline. SEM examination of randomly selected fractured test specimens indicated that bond failure was cohesive in nature, suggesting that the hydrogen peroxide treatment adversely affected the setting process of the glass ionomer cement.     

改良第八代粘接剂对龋影响牙本质粘接性能的影响

目的:第八代粘接剂Single Bond Universal(SBU)是最新一代的粘接剂,表没食子儿茶素没食子酸酯(Epigallocatechin gallate,EGCG)是基质金属蛋白酶抑制剂及偶联剂,本研究探讨添加EGCG是否可以提高SBU粘接强度及降低微渗漏.方法:将人中龋离体牙去除冠部釉质,龋指示剂下制备龋...     

Silicoating: evaluation of a new method of bonding composite resin to metal

Abstract — Silicoating is a new type of pretreatment of the metal in the resin-bonded bridge technique. The size of bond strength between resin cement and silicoated metal was investigated. Different resin cements, types of metal, and grain sizes of sand used for roughening the metal surface were tested. Furthermore, the effect on the bond strength of contamination with saliva and of thermocycling was measured. There was no difference of importance between the two resin cements tested. Bond strengths obtained with Wirobond were the highest and insensible to changes in resin cement, grain size of sand, and to thermocycling. It was found that sand of the smallest grain size used brought about the highest bond strengths. Contamination with saliva did not significantly reduce the size of the bond strengths. Rinsing the metal surfaces with water or ethanol after contamination restored the bond strengths to their original magnitude. By silicoating, a greater resistance to thermocycling was obtained. Nevertheless, except for Wirobond, a fall in bond strength was measured after thermocycling. Bond strengths of the size of those between etched enamel and composite resin were measured, and the Silicoater method seems a reliable pretreatment of the metal.     

Decrease of γ1 lattice constant with time in dental silver amalgam

Abstract— As a measure of the mercury content of the γ₁ phase in dental silver amalgam, the lattice constant of this phase in different amalgams was determined at various times after trituration. The lattice constants of amalgams prepared from alloys with a high silver content have lower values and show a steeper decline with time than amalgams with a low Ag-content. Therefore, since a higher lattice constant presumably is associated with increased mercury vapor, the mercury vapor emission from amalgams with a low Ag-content probably is greater than from amalgams with a high Ag-content, especially during the first weeks after trituration.     

Improvement of erosion resistance of a silicate cement by infrared radiation

Abstract – Silicate cement specimens have been exposed to infrared radiation for the purpose of improving the erosion resistance. Exposure for periods of 3–10 min, corresponding to a surface temperature of about 60–70°C, resulted in a reduced phosphate release of about 3–5 times that of a non-exposed group. the temperature distributions on the surface, as well as in a position 5mm beneath the surface, were measured with thermocouples during irradiation. A difference in temprature of about 20°C was registered between the surface and interior positions. the technique may be clinically exploited by exposing the restoration after insertion to a small infrared radiation source, available on the commercial market.     

Periodontal-derived cells attach to cementum attachment protein via α5β1 integrin

A specific collagenous cementum attachment protein (CAP) has been identified in human cementum which promotes selective cell migration towards and attachment of various periodontal derived cell populations to root surfaces in vitro. The CAP is known to support attachment of periodontal-derived cell via an RGD motif, which suggests an integrin-mediated mode of attachment. The purpose of the present study was to ascertain which integrin(s) are involved in the attachment of periodontal-derived cells to CAP. The integrins examined comprised subunits of the major receptors for fibronectin (alpha 5) and collagen (alpha 2, alpha 3), as well as the common beta 1 subunit which is present in many extracellular matrix receptors. The wells of 48-well non-tissue culture treated plates were coated with CAP (2 micrograms/ml). For negative and positive controls the wells were coated with bovine serum albumin and fibronectin (5 micrograms/ml), respectively. Human gingival fibroblasts and periodontal ligament fibroblasts were labeled with [3H]-proline, incubated with anti-integrin antibodies and added to the precoated wells. Attachment was assessed after incubating the cells for 1 h at 37 degrees C in the presence of the antibodies. Antibodies to alpha 5 and beta 1 inhibited the attachment of both human gingival fibroblasts and human periodontal ligament fibroblasts to CAP, while anti alpha 2 and alpha 3 antibodies did not affect the attachment. The binding of the fibroblasts to fibronectin was also inhibited by anti-alpha 5 and beta 1 antibodies, both of which are components of the "classical" fibronectin receptor and remained unaffected by the addition of anti-alpha 2 and alpha 3 antibodies. Proteins migrating in SDS-polyacrylamide gels in positions similar to the alpha 5 and beta 1 integrin subunits were present in fractions bound to a column of CAP coupled to Sepharose CL-4B. These results indicate that the attachment to CAP of the periodontal-derived cells, human gingival fibroblasts and human periodontal ligament fibroblasts, is mediated primarily via the integrin alpha 5 beta 1.     

Predicting the experience of dentinal caries or restorative dental treatment in adolescents using D1 and D3 visual caries assessments

Standardised epidemiological caries assessments used in oral health surveys have been shown to be poor at predicting whether a tooth surface will be treated restoratively when a patient visits a dentist. However, it has been argued that oral health surveys may be more relevant in determining needs at the level of an individual or groups of individuals. The objective of this study was to determine the discriminatory power of visual caries assessments at two thresholds (D₁ & D₃) in adolescents of average age 12.1 years to predict experience of dentinal caries 3 years later or the experience of restorative treatment (not re‐treatment) during the 3‐year period. The data was derived from a prospective 3‐year longitudinal study in which the dental care provided by 41 dentists for 403 adolescents was monitored. Dental caries experience was monitored by annual standardised assessments of caries undertaken by a single trained examiner. ROC analysis showed that caries assessed visually at the D₁ threshold in 12‐year‐olds was a better predictor (P < 0.001) of experiencing some dentinal caries after 3 years (Az = 0.781) than was caries assessed visually at D₃ threshold in 12‐year‐olds (Az = 0.670). Assessing caries visually at either the D₁ or the D₃ threshold had no discriminatory power for predicting whether an individual would experience some restorative treatment during the ensuing 3‐year period (Az for D₁ = 0.507; Az for D₃ = 0.518).     

酸蚀处理对新型自粘结树脂水门汀粘结强度的影响

目的:评价酸蚀处理对新型自粘结树脂水门汀Unicem与牙本质和牙釉质之间粘结强度的影响。方法:选取新鲜拔除的无龋坏人第三磨牙36个,制备颊侧牙本质粘结面和近、远中牙釉质粘结面,随机分为3组,每组12个牙,分别选用Unicem、磷酸酸蚀配合Unicem和Panavia F(对照组)进行粘结处理,分别测试牙本质、牙釉质粘结强度,并通过扫描电镜观察粘结界面。结果:在牙本质粘结强度上,Unicem组(12.84±2.29 MPa)与Panavia F组(14.93±3.73 MPa)之间无显著性差异(P>0.05),但均显著高于磷酸酸蚀配合Unicem组(9.12±1.54 MPa)(P<0.05);牙釉质粘结强度上,磷酸酸蚀配合Unicem组(17.24±7.62 MPa)和Panavia F组(17.99±3.66 MPa)无显著性差异(P>0.05),但均显著高于Unicem组(6.47±1.54MPa)(P<0.05)。结论:酸蚀处理可以显著提高自粘结树脂水门汀Unicem牙釉质粘结强度,却降低了牙本质粘结效果。     

酸蚀处理对新型自粘接树脂水门汀Clearfil SA Luting粘接性能影响的研究

目的：评价酸蚀处理对自粘结树脂水门汀Clearfil SA Luting与牙釉质和牙本质粘结强度的影响。方法：选取新鲜拔除的无龋坏人第三磨牙36个,制备近、远中牙釉质粘结面和颊侧牙本质粘结面,随机分为3组（n=12）,分别选用Clearfil SA Luting（SAC）、磷酸酸蚀配合Clearfil SA Luting进行粘结,测试两种处理方式对SAC与牙釉质、牙本质粘结强度的影响,同时与对照组Panavia F（PF）的粘接结果进行对照,并通过扫描电镜观察粘结界面。结果：牙釉质粘结强度测试结果显示,磷酸酸蚀配合SAC组（39.64±6.24）MPa显著高于未酸蚀组SAC（27.25±7.03）MPa组与对照组PF（22.92±7.13）MPa（P〈0.05）,但SAC未酸蚀组（27.25±7.03）MPa与对照组PF（22.92±7.13）MPa间无统计学差异（P〉0.05）。牙本质粘结强度测试结果显示,SAC未酸蚀组（10.09±3.26）MPa与PF对照组（14.23±6.39）MPa之间无显著性差异（P〉0.05）,但均显著高于SAC配合磷酸酸蚀组（1.13±1.12）MPa（P〈0.05）。结论：酸蚀处理可以显著提高自粘结树脂水门汀SAC与牙釉质粘结强度,但却降低了其与牙本质粘结效果。     

Demonstration of a K+ -stimulated and ouabain-sensitive p-nitrophenyl phosphatase activity in enamel- and dentin-forming tissues in the rat

abstract — Nitrophenyl phosphate hydrolysis was studied at neutral pH with tissue preparations of the rat secretory and maturation enamel organs and denial pulp. By introduction of inhibitors to nonspecific alkaline phosphatase activity and stimulants to the K⁺stiinulated and ouabain-sensitive p -nitrophenyl phosphatase activity, the latter-enzyme activity could be demonstrated. This enzyme activity is generally held to be representative of the enzyme sodium- and potassium-stimulated adenosine triphosphatase. The K⁺-stimulated activity was magnesium dependent and highly sensitive to fluoride. It was inhibited completely by 3 mM fluoride in the incubation medium and about 1 mM produced hall the maximum inhibition. The K⁺-independent enzyme activity was inhibited 50–60% by fluoride in concentrations between 3 and 15 mM. The high fluoride sensitivity of the K⁺-stimulated activity may perhaps help to explain the vulnerability of dental tissues to fluoride.     

In vitro study of the giant tubule collagen formation in bovine dentin by [3H]- proline incorporation

Abstract – Unerupted permanent bovine incisors studied by routine autoradiography using radioactive proline incorporation revealed collagen formation within the giant tubules situated in the incisal dentin. A high [³H]-proline labeling was seen within the pulpal vascularized portion of the giant tubules, as well as in association with groups of cells immediately incisal to the blood vessel loops. The incisal portion of the giant tubules showed no or insignificant [³H] -proline labeling.     

Towards a better understanding of the adhesion mechanism of resin-modified glass-ionomers by bonding to differently prepared dentin

Objectives

The purpose of this study was to evaluate the bonding effectiveness of a resin-modified glass-ionomer (RMGI) to differently prepared dentin and how this restorative material interacts with these distinct substrates. Also the potential adhesion-promoting role of a polyalkenoic-acid conditioner was assessed.

Methods

Forty-eight dentin surfaces were prepared from sound human molars and randomly distributed among 6 experimental groups. Fuji II LC (GC) was applied on bur-cut (100 μm diamond), fractured and Er:YAG laser-irradiated (200 mJ, 10 Hz, 31.4 J/cm²) dentin with or without the beforehand application of the aqueous polyalkenoic-acid conditioner, Cavity Conditioner (GC). After 7 days of storage in water at 37 °C, specimens were prepared for microtensile bond strength testing (μTBS), as well as for TEM characterization of the resultant RMGI-dentin interface. Statistical analysis of the μTBS results was performed using ANOVA and Tukey's test (p < 0.05).

Results

The use of conditioner resulted in a significantly higher bond strength only when dentin was prepared by diamond bur (p < 0.05). Laser irradiation induced micro-cracks on the dentin surface and led to the lowest bond strength, irrespective of the use of conditioner (p < 0.05). Fuji II LC was able to partially demineralise (up to 2.0 μm) and infiltrate bur-cut and fractured dentin, but no evident interaction was observed at the interface between the RMGI and laser-irradiated dentin.

Conclusions

Laser-induced surface modifications impaired the interaction of the RMGI with dentin, thereby negatively influencing its bonding effectiveness. The use of a polyalkenoic-acid conditioner remains crucial for the RMGI to bond effectively to bur-cut dentin.