A new 4-META/MMA-TBB adhesive resin has been studied and the effectiveness on adhesion to tooth substrates and dental alloys was reported previously. Here we are showing affection of cleaner or etchants on the adhesion between dentines and the 4-META/MMA-TBB resin. The adhesive strength becomes superior, 18 MPa, when dentines have been cleaned with a 10% citric acid-3% ferric chloride solution. On the other hand an etchant, phosphoric acid or citric acid alone, is not so effective as the mixed solution and the strength decreases to 6 MPa. Scanning electron microscopic study on pretreated dentine with several solutions is also carried out and it is found that debris on dentine should be removed but that in tubules is not necessary to be cleaned up to get good adhesion.

Acrylic Resins↗

PubMed1982

[Studies on dental self-curing resins (20) - adhesion mechanism of 4-META/MMA-TBB resin to dentine (author's transl)].

Scanning electron microscopic studies on dentine surface cleaned with a mixture of citric acid and ferric chloride, fractured surfaces parallel to the tubules of dentine and dentine with the cured adhesive and the partially demineralized fractured surfaces, tensile fractured surface of the joint on the dentine and cured adhesive resin tags impregnated in tubules were carried out to clarify the adhesion mechanism. Infiltration of monomers into dentine is more important to get good adhesion with dentine than the interlocking at dentinal tubules due to impregnated resin. Monomers with both hydrophobic and hydrophilic groups like 4-META promote the monomer infiltration. The infiltrated and cured adhesive layer in dentine is observed at the subsurface dentine zone. This zone has excellent resistance against acid demineralization.

Acrylic Resins↗

PubMed1982

[Studies on dental self-curing resins (22) - adhesion of 4-META/MMA-TBB resin to enamel (author's transl)].

Bovine enamels cleaned with citric acid and FeCl3 which had been brushed or ground were joined with PMMA rods with the 4-META/MMA-TBB cement. Their tensile adhesive strength was measured after post-treatments. Stable adhesive strength such as 6.2 MPa was obtained on an enamel which was brushed and washed with an aqueous solution of 10% citric acid-3% FeCl3 for 30 sec. even after a 60 times percolation test between 4 degrees C and 60 degrees C. It is adequate to clinics. The value increased to 16.1 MPa on ground enamel. These results suggest that phosphoric acid etching, essential nowadays, is not necessary for good adhesion to enamel. Monomers with both hydrophobic and hydrophilic groups like 4-META possess affinity with tooth substrates and promote the infiltration of cements into the enamel. The infiltrated monomers polymerized in situ and strong adhesion with the enamel took place. Comparison of the tag length formed in the enamel by cements, MMA-TBB, HNPM/MMA-TBB, Phenyl-P/MMA-TBB and 4-META/MMA-TBB supports this consideration.

Acrylic Resins↗

PubMed1982

[The effect of eugenol cement, CC, FC on the bonding strength of the adhesive resin to the tooth surface (author's transl)].

Bovine tooth surface pretreated with dental medicaments-Eugenol cement (ZOE), CC, FC was used to adhere to acrylic rod by adhesive resins-Clearfil F II and 4 META-MMA-TBB-O. The effects of the dental medicaments on the bonding strength of the adhesive resin were measured. The results were showed as follows: (1) Any pretreatment of the three medicaments reduced the bonding strength of Clearfil to both enamel and dentin surface. With 4-META-MMA-TBB-O resin system the bonding strength was reduced by ZOE and CC while it was increased by FC pretreatment. (2) On the enamel tooth surface premedicated with ZOE, FC or CC, the alcohol rinsing or mechanic grinding reduced the decrease of the bonding strength of Clearfil. With 4-META-MMA-TBB-O resin, the mechanic grinding of the premedicated enamel tooth surface increased the bonding strength. (3) On the premedicated dentin tooth surface, the mechanic grinding reduced the decrease of the bonding strength of 4-META-MMA-TBB-O. Alcohol rinsing, on the contrary, decreased the bonding strength. (4) On both fresh and premedicated dentin surface the bonding strength of Clearfil was lower than 3 MPa.

Acrylic Resins↗

PubMed1982

[Biomaterials].

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Alloys↗

PubMed1981

Determination of partition coefficients of acrylates, methacrylates, and vinyl monomers using high performance liquid chromatography (HPLC).

Retention times (Rt) for acrylates, methacrylates, and vinyl monomers were measured with two different columns (C18 Corasil and C8 LiChrosorb) using reverse-phase HPLC in order to obtain their partition coefficients between 1-octanol and water (log P). The log P values of test compounds were determined from the regression curves between RT and log P values of a number of standards using C8 LiChrosorb. The log P values obtained in this manner agreed closely with the log P values observed in previous studies. However, the peaks of these compounds were not sharp and some compounds were eluted for more than 10 min. Thus, the measurement of accurate Rt values is tedious. C18 Corasil was therefore used for this experiment in a mobile phase (methanol : water = 85 : 15). The Rt of some methacrylates with P values over 4 were delayed due to the hydrophobic interaction between these compounds and the C18 packing material. However, in the measurable region of the log P values (about -1 to +4), log P correlated linearly with log Rt following two different regression curves: one for aliphatic and aromatic compounds with the functional groups (r = 0.92), and the other for compounds without these groups (r = 0.99). It is concluded that log P values of methacrylates widely used in dentistry can be determined easily and accurately by HPLC.

1-Octanol↗

PubMed1981

Binding of eugenol and o-ethoxybenzoic acid to bovine serum albumin.

The binding constants (log K) of eugenol, o-ethoxy-benzoic acid, and their analogues, plus other organic compounds widely used in dentistry with bovine serum albumin, were examined with respect to the partition coefficients of these compounds in octanol-water (log P). Linear relationships between log K and log P values were obtained with high relative coefficients. Eugenol and o-ethoxybenzoic acid showed a relatively large log K value.

Alcohols↗

PubMed1981

4-META opaque resin--a new resin strongly adhesive to nickel-chromium alloy.

1) A new adhesive opaque resin containing a reactive monomer, 4-methacryloxy-ethyl trimellitate anhydride (4-META), was prepared, and its application to thermosetting acrylic resin veneer crowns was studied. 2) The 4-META opaque resin was applied to a variety of nickel-chromium dental alloy specimens which had undergone different treatment, and endurance tests were conducted to evaluate the durability of adhesion. 3) Stable adhesion against water penetration was achieved with metal surfaces first etched with HCl and then oxidized with HNO3. A bond strength of 250 kg/cm2 was maintained even after immersion in water at 37 degrees C for 30 wk or at 80 degrees C for ten wk. Furthermore, this value did not decrease even after the specimens were subjected to 500 thermal cycles. 4) The 4-META opaque resin studied can eliminate the necessity for retention devices on metal castings. 5) The smooth 4-META opaque resin should have no adverse effects on gingivae.

Acrylates↗

PubMed1981

[Some cautions in the use of composite resins].

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Composite Resins↗

PubMed1981

[Physical properties of adhesive 4-META resin cement (author's transl)].

4-Methacryloxyethyl trimellitate anhydride (4-META) had been reported to be a suitable monomer which promotes adhesiveness of PMMA rods with tooth substrates and metals. Previously an adhesive opaque resin which could eliminate mechanical retention devices from metal surface of crown and bridge metal frame was suggested. A new denture base resin, which is adhesive to metal denture plate, was also reported based on 4-META in MMA. We are going to publish a new application of 4-META to an adhesive dental cement in this paper. The physical properties of the new cement were measured: film thickness, 15 mu, tensile strength, 228 kg/cm2, compressive strength 920 kg/cm2, transvers strength , 530 kg/cm2, water sorption, 1.97 mg/cm2. Tensile adhesive strength of the cement was higher than 100 kg/cm2 between PMMA rods and dentine, enamel, dental alloys, and the stability was acceptable.

Acrylates↗

PubMed1981

[Adhesive resins and wing type bridge].

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Denture, Partial↗

PubMed1981

[Determination of hydrophobic parameters (log PHPLC) for methacrylates, initiators and miscellaneous compounds used in dentistry by high-performance liquid chromatography (HPLC) (author's transl)].

The use of partition coefficients Poct obtained from an n-octanol-water partitioning system has become a standard method for modelling biological membranes and thereby quantifying the hydrophobicity of a given compound as log Poct = log Coct--log Cwater. However, there is no convenient method available to determine the log Poct value accurately. The conventional flask-shaking method is a laborious and time consuming procedure, often complicated by instability in aqueous media, impurities and the tendency for the compound to dissociate. There have been recently attempts using HPLC to determine the hydrophobicity of organic compound. The retention behaviour of about fifty organic compounds in HPLC systems have been examined. Using methanol-water as the mobile phase, a linear relationship between the volume fraction of organic modifier and the logarithm of the capacity factor (log K') over limited range was obtained for standards. However, unfortunately, the correlation between log Kw obtained from the extrapolated K' values with pure water as eluent and log Poct values was not good (r = 0.83). Using this octadecylsilyl column with the mobile phase (methanol: water = 70:30), standards fall on the three straight lines with good correlations (r = 0.99) between the log Poct and log K' values.: one for benzenes and aliphatic compounds, the second for phenols, anilines and hydrogenacceptor benzene derivatives and the third for benzoic acids, respectively. The PHPLC values of methacrylates, initiators and miscellaneous compounds which are widely in dentistry were determined using these three regression lines.

Acrylates↗