JP4628050B2 - Dental cement composition - Google Patents

Description

  The present invention relates to a dental cement composition. More specifically, the present invention relates to a dental cement composition that can be suitably used as a temporary dental cement excellent in biological safety, particularly as a superstructure temporary cement in an oral implant.

  In the field of dentistry, an operator-removable temporary cement is used for temporary crown temporary attachment and superimposition of oral implants. The mounting method of the superstructure in the oral implant is roughly divided into screw fixing method and cement fixing method. From the viewpoint of aesthetics and ease of operation, the cement fixing method using temporary cement is used. The frequency of doing is increasing.

  As the temporary cement, carboxylate cement and eugenol cement are mainly used in clinical practice, and the main component of the powder is zinc oxide. Although zinc is an essential element, it is known as an element with high cytotoxicity and may cause metal allergy.

  On the other hand, in the field of dentistry, calcium phosphate cement has been developed that does not contain a transition metal element or a zinc group element, has high biocompatibility, and is a main inorganic component of living hard tissues such as teeth and bones. As an example thereof, a hydraulic cement that has biocompatibility and is condensed by a hydration reaction between a calcium phosphate compound and water to treat or repair a tooth defect void (see, for example, Patent Document 1). ), And a dental curable composition (for example, see Patent Document 2) obtained by mixing water and a water-soluble polymer acid into calcium phosphate and a curable liquid.

  However, all of these compositions have a long setting time as temporary crown temporary cement and temporary implant cement for oral implants, and the retention force between the abutment and the upper structure in oral implants. Is not sufficient and has not yet been used because of its high decay rate.

JP-A-5-095993 Japanese Examined Patent Publication No. 62-42625

  The present invention has been made in view of the above prior art, does not contain any transition metal element or zinc group element, is excellent in biosafety, and has an appropriate curing time and an abutment and oral structure in an oral implant. It is an object of the present invention to provide a dental cement composition having mechanical properties such as a holding power.

  The present invention relates to a dental cement composition containing (a) calcium phosphate, (b) calcium hydroxide, (c) polyalkenoic acid and (d) water.

  The dental cement composition of the present invention does not contain any transition metal element or zinc group element, is excellent in biosafety, and has an appropriate setting time and a mechanical property such as retention force between the abutment and the superstructure in the oral implant. Characteristics. Therefore, the dental cement composition of the present invention can be suitably used as a temporary wearing cement excellent in biological safety, particularly as a cement for temporarily attaching an upper structure and an abutment in an oral implant.

  The present inventors do not contain any transition metal element or zinc group element, have excellent biosafety, and have appropriate curing time and mechanical properties such as retention force between the abutment and the superstructure in the oral implant. With the object of providing a dental cement composition, a carboxylate cement using calcium phosphate as a temporary cement powder was studied.

In conventional carboxylate cements and the like, the cement is hardened by using zinc ions (Zn ²⁺ ) eluted from zinc oxide powder as a crosslinking agent for gelation of polycarboxylic acid.

On the other hand, in a cement using calcium phosphate as a powder, the calcium ion (Ca ²⁺ ) supplied from the calcium phosphate causes a cross-linking reaction with the polycarboxylic acid, so it hardens. The performance of the abutment and the superstructure in the oral implant is insufficient.

  Therefore, as a result of intensive investigations focusing on such facts, the present inventors have added an appropriate amount of calcium hydroxide to the cement, and when the pH is increased, the carboxyl group of the polycarboxylic acid is reduced. Ionized, accelerated hardening reaction and improved retention of superstructure in abutments and oral implants, suppressed excessive dissolution of calcium phosphate, reduced soluble calcium salt production, cement composition after hardening It has been found that the rate of decay of can be reduced, and the present invention has been completed.

  Since the cement composition of the present invention does not contain any transition metal element or zinc group element, it is excellent in biological safety. In addition, calcium hydroxide is used in the cement composition of the present invention, and this calcium hydroxide increases the pH and ionizes the carboxyl group of the polyalkenoic acid. As a result, since the hardening reaction of the cement composition is promoted, the compressive strength is higher than that of the commercially available zinc oxide Eugenol cement, and the excellent effect of improving the holding power against metals and ceramics is exhibited.

  Therefore, the cement composition of the present invention can be suitably used as a temporary wearing cement in dental treatment, and in particular, as a temporary wearing cement for fixing an upper structure of an oral implant in an operator removable manner. It is expected to contribute greatly to dental care as a temporary cement with excellent safety.

  In the present specification, the “temporary cement” means a cement prepared assuming temporary tacking. Temporary cement is used in everyday situations by attaching a dental prosthesis in a removable manner, and is used in everyday situations, such as cement for confirming aesthetics, functional recovery, wearing feeling, and temporary crowns during technical work. It is used as a cement used for temporary fixing, a cement for attaching an upper structure of an oral implant to an operator removable type, and the like.

  In addition, “oral implant” means, for example, putting an artificial tooth root in a jaw that has lost teeth in order to restore the function of the oral cavity. The oral implant is mainly connected to the implant body for mounting an implant body (an artificial tooth root portion embedded in the jawbone and engrafted with bone) and an abutment (an artificial dental crown portion (superstructure in the oral implant)). Abutment device], and the upper structure of the oral implant (artificial crown portion to be attached to the implant).

  In the present invention, the implant body and the abutment are not particularly limited as long as they are used in the dental field. Moreover, the superstructure in the oral implant is not particularly limited as long as it is used in the dental field. Examples of the material constituting the superstructure in the oral implant include metals, ceramics, and dental composite resins. In addition, since the superstructure in the oral implant and the attachment of the abutment must be removable by the operator, a screw fixing method and a cement fixing method using temporary cement are mainly used for the attachment.

  In the present invention, calcium phosphate is used in place of zinc oxide used in conventional carboxylate cement. This calcium phosphate expresses excellent biosafety.

  Examples of calcium phosphate include α-tricalcium phosphate (α-TCP), tetracalcium phosphate (TTCP), dicalcium phosphate dihydrate (DCPD), hydroxyapatite (HAP), fluorapatite (FAP), and fluorination. Apatite, carbonate-containing apatite (CAP) dicalcium phosphate anhydrous (DCPA), β-tricalcium phosphate (β-TCP) octacalcium phosphate (OCP), amorphous calcium phosphate (ACP), anhydrous monocalcium phosphate (MCPA) ), Primary calcium phosphate monohydrate (MCPM), and the like, and these can be used alone or in admixture of two or more. Among these, tetracalcium phosphate is preferable from the viewpoint of the disintegration rate of the cement composition after hardening, the mechanical strength, and the retention strength between the abutment and the superstructure in the oral implant.

  In addition, the manufacturing method of a calcium phosphate may be what kind of method, and this invention is not limited by this manufacturing method.

  The calcium phosphate is preferably a powder. The average particle diameter of calcium phosphate is 0.1 to 100 μm, preferably 1 to 20 μm, from the viewpoint of the film thickness of the cement composition in a paste state before hardening and the mechanical strength of the cement composition after hardening. preferable.

  The shape of the calcium phosphate particles does not affect the essence of the present invention, and may be any shape such as a spherical shape, a crushed shape, a plate shape, and a needle shape.

  Calcium hydroxide increases the cure rate of the cement composition of the present invention and reduces the decay rate of the cement composition after cure, while mechanical strength and abutments and superstructures in oral implants It is a component used to improve the holding power with the body.

  The calcium hydroxide is preferably a powder. The average particle diameter of calcium hydroxide is 0.1 to 100 μm, preferably 1 to 20 μm, from the viewpoint of the film thickness of the cement composition in a paste state before hardening and the mechanical strength of the cement composition after hardening. It is desirable.

  The shape of the calcium hydroxide particles does not affect the essence of the present invention, and may be any shape such as a spherical shape, a crushed shape, a plate shape, and a needle shape.

  From the viewpoint of increasing the curing rate, the amount of calcium hydroxide is desirably 15 parts by weight or more, preferably 25 parts by weight or more with respect to 100 parts by weight of calcium phosphate, and suppresses the pH from becoming too high. For example, from the viewpoint of maintaining the holding force between the abutment and the superstructure in the oral implant, it is desirably 55 parts by weight or less, preferably 45 parts by weight or less with respect to 100 parts by weight of calcium phosphate. From these viewpoints, the amount of calcium hydroxide is 15 to 55 parts by weight, preferably 25 to 45 parts by weight, with respect to 100 parts by weight of calcium phosphate.

  In this specification, polyalkenoic acid means a polymer having a carboxyl group. A polyalkenoic acid is an essential component in the composition of the present invention because a curing reaction occurs due to a chelate reaction between a carboxyl group of polyalkenoic acid and calcium ions supplied from calcium phosphate.

  Preferable examples of the polyalkenoic acid include unsaturated carboxylic acid polymers such as unsaturated monocarboxylic acid polymers and unsaturated dicarboxylic acid polymers.

  Specific examples of polyalkenoic acid include acrylic acid, methacrylic acid, 2-chloroacrylic acid, 2-cyanoacrylic acid, aconitic acid, mesaconic acid, maleic acid, itaconic acid, fumaric acid, glutaconic acid, citraconic acid, utraconic acid, etc. And a homopolymer of the unsaturated carboxylic acid, a copolymer with another monomer copolymerizable with the unsaturated carboxylic acid, and the like.

  The amount of the unsaturated carboxylic acid is preferably 50 mol% or more of the total amount of the unsaturated carboxylic acid and the other monomer copolymerizable with the unsaturated carboxylic acid.

  As the monomer copolymerizable with the unsaturated carboxylic acid, an ethylenically unsaturated polymerizable monomer is preferable. Specific examples of the ethylenically unsaturated polymerizable monomer include, for example, styrene, acrylamide, acrylonitrile, methyl methacrylate, acrylate, allyl chloride, vinyl acetate, 1,1,6-trimethylhexamethylene dimethacrylate, and the like. Can be mentioned.

  Among polyalkenoic acids, acrylic acid homopolymers are used in view of the setting time of the cement composition of the present invention, the rate of disintegration after hardening, the mechanical strength, and the retention strength between the abutment and the superstructure in the oral implant. Maleic acid homopolymers and copolymers of acrylic acid and maleic acid are preferred.

  From the viewpoint of increasing the mechanical strength and durability of the cured product of the dental cement composition of the present invention, the weight average molecular weight of the polyalkenoic acid is desirably 1000 or more, preferably 5000 or more. From the viewpoint of preventing the operability from decreasing by increasing the viscosity at the time of mixing the cement composition and improving the operability, it is preferably 50,000 or less, preferably 40,000 or less. From these viewpoints, the weight average molecular weight of the polyalkenoic acid is 1000 to 50000, preferably 5000 to 40000.

  The amount of polyalkenoic acid is desirably 2 parts by weight or more, preferably 5 parts by weight or more based on 100 parts by weight of calcium phosphate from the viewpoint of mechanical strength due to the curing reaction between polyalkenoic acid and calcium phosphate. From the viewpoint of suppressing the viscosity and pH of the product from becoming too low, it is desirable that the amount be 600 parts by weight or less, preferably 400 parts by weight or less with respect to 100 parts by weight of calcium phosphate. From these viewpoints, the amount of polyalkenoic acid is 2 to 600 parts by weight, preferably 5 to 400 parts by weight, with respect to 100 parts by weight of calcium phosphate.

  Water is an essential component as a medium for the reaction of polyalkenoic acid and calcium phosphate in the cement composition of the present invention, and is a component used to adjust the viscosity of the cement composition in a paste state. Water can be used without particular limitation as long as it does not contain impurities that adversely affect the hardening of the cement composition and the development of adhesive strength with the teeth, but distilled water and ion exchange water are preferred. .

  The amount of water is desirably 4 parts by weight or more, preferably 10 parts by weight or more based on 100 parts by weight of calcium phosphate, from the viewpoint of promoting the curing reaction between polyalkenoic acid and calcium phosphate, and the viscosity of the cement composition. From the viewpoint of suppressing the decrease in the amount of calcium phosphate, the amount is not more than 600 parts by weight, preferably not more than 400 parts by weight with respect to 100 parts by weight of calcium phosphate. From these viewpoints, the amount of water is 4 to 600 parts by weight, preferably 10 to 400 parts by weight with respect to 100 parts by weight of calcium phosphate.

  The weight ratio of polyalkenoic acid to water (polyalkenoic acid / water) gives an appropriate viscosity to the paste-like cement composition before curing, and from the viewpoint of adjusting the curing reaction between polyalkenoic acid and calcium phosphate. It is 90 or more, preferably 40/60 or more, and from the viewpoint of suppressing the viscosity of the cement composition from becoming too high, it is desirably 80/20 or less, preferably 60/40 or less. From these viewpoints, the weight ratio of polyalkenoic acid to water (polyalkenoic acid / water) is desirably 10/90 to 80/20, preferably 40/60 to 60/40.

  The cement composition of the present invention includes, for example, a mixture of calcium phosphate powder and calcium hydroxide powder (hereinafter referred to as a powder component) and a mixture of polyalkenoic acid and water (polyalkenoic acid aqueous solution) (hereinafter referred to as a liquid component). It is obtained by mixing immediately before use to make a paste.

  Since the ratio of the powder component to the liquid agent component varies depending on the particle diameter, particle shape, etc. of the powder component, it cannot be determined unconditionally. Usually, the amount of the powder component per 1 g of the liquid agent component is preferably 0.1 g or more, preferably 0.3 g or more from the viewpoint of the mechanical strength of the cement composition. From the viewpoint of preventing the viscosity from becoming too high, it is desirably 5 g or less, preferably 3 g or less. From these viewpoints, the amount of the powder component per 1 g of the liquid agent component is 0.1 to 5 g, preferably 0.3 to 3 g.

  Thus, the cement composition of the present invention can be obtained by mixing the powder component and the liquid component.

  Next, the present invention will be described in more detail based on examples, but the present invention is not limited to such examples.

Examples 1 to 6 and Comparative Example 1 (However, Examples 2 to 4 are reference examples.)
As calcium phosphate, tetracalcium phosphate (hereinafter referred to as TTCP) (average particle size: 8.5 μm), dicalcium phosphate (hereinafter referred to as DCPA) (average particle size: 9.5 μm), hydroxyapatite (hereinafter referred to as HAP) (average) Particle size: 8.2 μm) or octacalcium phosphate (hereinafter referred to as OCP) (average particle size: 8.9 μm) was used. Further, polyacrylic acid having a weight average molecular weight of 25000 was used as polyalkenoic acid, and distilled water was used as water.

  A cement composition was prepared by mixing a powder component composed of calcium phosphate and calcium hydroxide and a liquid component composed of polyalkenoic acid and water so as to have the composition shown in Table 1.

  As physical properties of the obtained cement composition, curing time, compressive strength and disintegration rate, and retention force between the abutment and the superstructure in the oral implant were examined according to the following methods. The results are shown in Table 1.

(1) Curing time, compressive strength and disintegration rate
The curing time, compressive strength, and disintegration rate were measured according to the methods specified in JIS T-6602 and JIS T-6606.

  The curing time is 5 to 25 minutes, preferably 5 to 20 minutes, considering the actual use situation in clinical practice. Further, the compressive strength and the holding force for the superstructure (hereinafter simply referred to as holding force) are preferably higher, and the disintegration rate is preferably lower.

(2) Holding power After mounting the cylinder (inside diameter 3.5 mm) that constitutes the superstructure in the oral implant to a stainless steel jig, cement the pure titanium abutment (outside diameter 3.3 mm) with the cylinder. A test sample was prepared by temporarily attaching at 37 ° C. for 60 minutes.

  The obtained test sample was immersed in water at 37 ° C for 24 hours, then removed from the water, and held at a cross head speed of 2 mm / min using a tensile tester (EZ Test, manufactured by Shimadzu Corporation). The force was measured.

  Gold cylinders (gold alloy cylinders, Nobel Biocare, part number: Cera One Syste) and ceramic caps (Nobel) are used to form the superstructure of oral implants. -Product name: Cera One System] manufactured by Nobel Biocare, Inc. was used.

  From the results shown in Table 1, each of the cement compositions obtained in each of the examples was moderate in that calcium hydroxide was used as compared with the cement composition obtained in Comparative Example 1. It can be seen that it has a good curing time, has a low disintegration rate, and is excellent in both compressive strength and holding power. Among them, the cement compositions obtained in Examples 1 to 4 have a more appropriate setting time, a lower disintegration rate, and better compression strength and holding power. Recognize. Furthermore, in Example 1, since tetracalcium phosphate is used as calcium phosphate, it turns out that a disintegration rate is the lowest and it is the most excellent in both compressive strength and holding power.

Example 7
As calcium phosphate, tetracalcium phosphate (TTCP) (average particle size: 8.5 μm, manufactured by Wako Pure Chemical Industries, Ltd.) was used. Calcium phosphate and calcium hydroxide (average particle size 10.2 μm) were added to 100 parts by weight of calcium phosphate. A powder component was obtained by adjusting the amount of calcium hydroxide to 33 parts by weight.

  On the other hand, a polyalkenoic acid aqueous solution [polyacrylic acid aqueous solution: commercially available carboxylate cement solution [manufactured by CG (G-C), trade name: LIVCARBO]] was used as a liquid component.

  Next, the powder component and the liquid component were mixed so that the amount of the powder component per 1 g of the liquid component was 0.63 g to prepare a cement composition.

  The physical properties of the obtained cement composition were examined in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 2
In Example 7, a cement composition was prepared in the same manner as in Example 7 except that calcium hydroxide was not used.

  The physical properties of the obtained cement composition were examined in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 3
As a conventional cement composition, a commercially available representative temporarily worn carboxylate cement in which a polycarboxylic acid and zinc oxide undergo a chelate curing reaction [manufactured by Matsukaze Co., Ltd., trade name: High Bond Temporary Cement (Hard) (HY- BOND TEMPORARY CEMENT (HARD)] and mixed so that the amount of the powder component per 1 g of the liquid component was 1.60 g to prepare a cement composition.

  The physical properties of the obtained cement composition were examined in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 4
Typical temporary cemented zinc oxide Eugenol cement commercially available on the basis of zinc oxide and eugenol as a conventional cement composition (manufactured by GC Corporation, trade name: EUGENOL CEMENT) Was mixed so that the amount of the powder component per 1 g of the liquid component was 4.55 g, to prepare a cement composition.

  The physical properties of the obtained cement composition were examined in the same manner as in Example 1. The results are shown in Table 2.

  From the results shown in Table 2, since Comparative Example 2 does not use calcium hydroxide, it has a longer setting time than the commercially available cement compositions (Comparative Examples 3 and 4). It can be seen that the compression strength is low and the disintegration rate is high.

  On the other hand, in Example 7, since calcium hydroxide is used, compared with Comparative Example 2 in which calcium hydroxide is not used, the curing time is short, the compressive strength is high, and the collapse rate is further increased. It can be seen that is as low as 1%.

  Moreover, the retention strength between the abutment of the cement composition obtained in Example 7 and the upper structure in the oral implant is significantly higher than that in the case of using commercially available temporary cement (Comparative Examples 3 and 4). I understand.

  From the above, since the calcium hydroxide is used for the cement composition obtained in Example 7, the pH of the cement composition is increased to some extent, and the carboxyl group of polyalkenoic acid is ionized. It is considered that the curing reaction was promoted, and the retention force for the superstructure in the abutment or oral implant was increased.

  Moreover, according to Example 7, since the pH of the resulting cement composition increases at the initial stage of mixing the powder component and the liquid component, dissolution of the calcium phosphate powder is suppressed, and the amount of soluble calcium salt produced is reduced. Therefore, it is considered that the decay rate has decreased.

  In addition, since the cement composition obtained in Example 7 does not contain heavy metal elements such as zinc in the raw material as shown in Table 2, it can be seen that the cement composition is excellent in biosafety.

  The cement composition of the present invention can be suitably used as a superstructure temporary cement for an oral implant.

Claims (2)

(A) tetracalcium phosphate, (b) calcium hydroxide, dental cement composition containing (c) polyalkenes acid and (d) water. Dental cement composition according to claim 1 Symbol placement is 15 to 55 parts by weight with respect to amount of tetracalcium 100 parts by weight of phosphoric acid calcium hydroxide.