JPH03178909A - Root canal filler - Google Patents

Abstract

PURPOSE:To provide the title biocompatible filler especially excellent in sealing ability, comprising a unsaturated carboxylic acid polymer solution as curing liquid and a powdery agent composed of tricalcium alpha-phosphate powder, magnesium oxide powder and iodoform powder. CONSTITUTION:The objective filler comprising (A) a powdery agent pref. <=20mum in particle size composed of (1) 100 pts.wt. of tricalcium alpha-phosphate powder, (2) 2-12 pts.wt. of magnesium oxide powder and (3) 5-60 pts.wt. of iodoform powder and (B) a curing liquid, a 10-40wt.% solution of a unsaturated carboxylic acid polymer (pref. acrylic acid homopolymer or a copolymer of acrylic acid and a small amount of itaconic acid, maleic acid etc.) at the weight ratio A/B=1.0-2.5. The present filler is free from bioirritability and excellent in the adhesivity to gutta-percha points and in operability, being effective for root canal-filling therapies using, in particular, its combination with gutta-percha points.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a root canal filling material used in dental treatment, and particularly to a root canal filling material that is effective for root canal filling treatment when used in combination with gutta percha points. Regarding materials.

[Prior art and its problems to be solved]

In dental treatment, when treating pathological causes such as pulpitis and infected root canals, root canals that have become void due to pulp removal or the like are treated by means such as filling with root canal filling material.

Typical conventional root canal filling treatments include a method in which only root canal filling material is tightly filled into the root apex, and a method in which gutta percha points and root canal filling material are used together to fill and seal the root canal. It is something.

The typical root canal filling material used in the former method is calcium hydroxide glue, and the root canal filling material used in the latter method is zinc oxide nisinol. Cement is known as a typical example.

However, when calcium hydroxide-based glue is used, there is a problem in that it is irritating because p++ increases in the vicinity of the filling. On the other hand, when zinc oxide cosinol cement was used, there was 111 problem that it had no biocompatibility.

In addition, biocompatible α-
Example of using tricalcium phosphate powder (JP-A-62-1
No. 9508), but since this root canal filling material uses a polyacrylic acid aqueous solution as a curing liquid, this also has problems such as lowering the pH and poor operability.

In view of the current situation, the present inventors conducted intensive studies on root canal filling materials in order to solve the above-mentioned problems, and as a result, they arrived at the present invention.

[Failure to solve the problem]

That is, the present invention provides: (i) a powder [P] in which 2 to 12 parts by weight of magnesium oxide powder and 5 to 60 parts by weight of iodoform powder are blended with 100 parts by weight of α-tricalcium phosphate powder; ) a curing liquid "■7" which is a 10 to 40% by weight aqueous solution of an unsaturated carboxylic acid polymer, and the weight ratio CP of the above [P] and [L]]/
[:Relating to a root canal filling material whose Ll is 1.0 to 2.5.

The following properties are generally required for root canal filling materials:

(i) The mixture of root canal filling tNjM has appropriate kinematic viscosity,
It adapts well to the Gatsuta Percha point, and is easy to land.

(ii) When bathing outside the apical foramen, it does not irritate the surrounding tissues;
Absorption is rapid.

(iii) It has a reasonable curing time and has a working time.

(iv) Excellent sealing properties.

(v) It has X-ray contrast property.

(Vl) Good operability.

Root canal filling +A of the present invention is biocompatible and is an epoch-making product that has the above-mentioned required properties, especially sealing properties.

The present invention will be explained in detail below.

The powder [P] constituting the root canal filling material of the present invention consists of α-tricalcium phosphate powder, magnesium oxide powder, and iodoform powder.

The α-tricalcium phosphate can be produced by a known method, for example, by the following method.

That is, γ-calcium pyrophosphate and calcium carbonate are uniformly mixed in equimolar amounts, thoroughly dried, and then
It can be obtained by calcining at 0 to 1400°C, preferably around 1250°C for about 1 hour, and pulverizing the resulting product into a fine powder with a particle size of 100 μm or less. Another method is to uniformly mix calcium hydrogen phosphate trihydrate and calcium carbonate at a molar ratio of 2:1, and then im
It can also be obtained by firing and pulverizing under almost the same conditions as described above.

The magnesium oxide powder is obtained by calcining magnesium hydroxide or basic magnesium carbonate at 900 to 1200°C, preferably around 1000°C for about 2 hours, and finely pulverizing the resulting product to obtain a fine powder with a particle size of 100 μm or less. can be obtained by

The iodoform powder can be produced by a known method and is commercially available.

The powder [P] used in the present invention consists of the above-described tricalcylalpha phosphate, powder, magnesium oxide powder, and iodoform powder. Preferably, the mixture has a particle size of 20 μm or less.

The appropriate mixing ratio is 100 parts by weight of α-tricalcium phosphate powder, 2 to 12 parts by weight of magnesium oxide powder, and 5 to 60 parts by weight of iodoform powder. If the amount of magnesium oxide powder is less than the above ratio, the pit of the root canal filling material obtained will be as low as 5 or less, causing bioirritation, and the coagulation time will be short, less than 30 minutes, resulting in poor workability, and conversely, it will be too much. This is not preferable because the compressive strength of the resulting cured product becomes poor and the sealing properties become insufficient. In addition, if the iodoform powder is less than the above ratio, the X-ray contrast properties of the root canal filling material will be insufficient, and the adhesion to gutta-percha points and root canal walls will be poor; conversely, if it is too much, the relative α - Since the amount of tricalcium phosphate powder decreases, the curing properties of the root canal filling material deteriorate, which is undesirable.

The powder [P] used in the present invention consists of the three components mentioned above,
Furthermore, if necessary, hydroxyapatite [Ca1o(
PO4)6(DH)2], β-tricalcium phosphate [β
-Ca, (PO4) 2], tetracalcium phosphate [
:Ca4P20s: Calcium phosphate powder such as 1 is α
- It is possible to mix 50 parts by weight or less with respect to 100 parts by weight of tricalcium phosphate powder.

It is also possible to add small amounts of X-ray contrast agents such as barium sulfate, powder, basic bismuth carbonate powder, and neutralizing agents such as magnesium hydroxide powder, calcium hydroxide powder, and calcium oxide powder.

The hardening liquid constituting the root canal filling material of the present invention is an aqueous solution of a polycarboxylic acid polymer.

The polycarboxylic acid polymer is preferably a homopolymer of acrylic acid or a copolymer of acrylic acid with a small amount of itaconic acid, maleic acid, fumaric acid, etc., or in some cases, a polymer known from cement compositions for Nanka, etc. methacrylic acid,
Typical examples include unsaturated acids such as aconitic acid, citraconic acid, glutaconic acid, mesaconic acid, and tiglic acid, or lower alkyl esters thereof, or copolymers of acrylic acid with lower alkyl esters.

In addition, the concentration of the aqueous solution of the polycarboxylic acid polymer is 10 to 40
If the weight % is appropriate, and the aqueous solution concentration is less than the above range, the viscosity will be lost during kneading, resulting in poor workability.

On the other hand, if it is larger than the above range, the pH of the kneaded and cured product becomes low, resulting in biological irritation or poor operability, which is not preferable.

As explained above, the curing liquid [L] used in the present invention is composed of an aqueous solution of an unsaturated carboxylic acid polymer, but is chlorinated as necessary), or a water-soluble salt of calcium or magnesium, and It is also possible to add small amounts of thickeners, surfactants, preservatives, antibacterial agents, etc.

The root canal filling material of the present invention is composed of the powder [P] and hardening agent [L] described above, and they are mixed in a weight ratio [,P:] / [:L:] of 1. It is kneaded and used at a ratio of .0 to 2.5. CP]/C1,] ratio is 10
If it is less than 100%, the viscosity of the kneaded product will be low, a viscous kneaded product will not be obtained, and the workability of filling the root canal will be poor.

On the other hand, if it exceeds 2.5, it becomes difficult to knead, and the kneaded product has no viscosity and becomes rough.

The powder agent [P] and hardening liquid [L] of the present invention are kneaded immediately before use, and then used.

The kneading operation method for the root canal filling shrine of the present invention is not particularly limited, and any method conventionally used in the field of dental cement may be used, for example, the method specified in JIS-T-6602 can be used. .

[Effects of the Invention] The root canal filling material of the present invention has α-
It is biocompatible because tricalcium phosphate is used, and there is no biostimulation effect due to the neutralization effect of magnesium oxide.Furthermore, it is produced by a chelate reaction between magnesium ions eluted from magnesium oxide and unsaturated carboxylic acid polymer. Produces a rubber-like substance, which improves waterproofing and sealing properties. In addition, it is suitable as a root canal filling shrine because it has excellent adhesion to gutta-percha points and operability.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Examples 1 to 4 and Comparative Examples 1 to 3 T-calcium pyrophosphate and calcium carbonate were mixed in equimolar amounts by a known method, calcined to combine α-tricalcium phosphate, and pulverized to pass through a 400-mesh sieve. was passed through to obtain α-tricalcium phosphate powder with a predetermined particle size.

The thus obtained α-tricalcium phosphate powder (referred to as α-TCP) was mixed with other powder components shown in Table 1, and the mixture was prepared according to the method of JIS-T-6602. (The numbers in the table indicate parts by weight).

The thus prepared kneaded product was examined for its operability, adhesion to gutta-percha points, X-ray contrast properties, sealing properties, and curing time, and the results are shown in the lower column of Table 1.

Separately, the powder and the curing liquid were kneaded uniformly for 1 minute, the kneaded product was put into a container, the surface was flattened and a filter paper was placed on it, and 150 seconds after the start of kneading, water was added dropwise and the filter paper After moistening and leaving it sealed for 48 hours, use a flat type pH electrode (flat type composite electrode GST-5313F manufactured by Toa Denpa Kogyo ■).
) was brought into contact with a filter paper and the surface pH of the kneaded product was measured.

As is clear from the test results in Table 1, the root canal filling material of the present invention has a neutral r+H ratio, has extremely low bioirritation, and has excellent operability.
It had good adhesion, X-ray contrast properties, and sealing properties, and was suitable as a root canal filling material.

On the other hand, in Comparative Example 1 in which magnesium oxide was not blended, the sealing property was insufficient and the curing time was too short.

On the contrary, in Comparative Example 2 in which magnesium oxide was added in excess, the sealing properties were poor and the kneaded product did not harden. In addition, Comparative Example 3 (50% by weight), in which the aqueous solution concentration was too high as a curing liquid, was irritating to living organisms, had high viscosity during kneading, had poor operability, and had an excessively long curing time.

Note 1) Hydroxyapatite powder produced by dry synthesis using monocalcium phosphate and calcium carbonate as raw materials.

Note 2) Manufactured by firing magnesium hydroxide at 1000°C for 2 hours.

Note 3) Copolymer with a molecular weight of approximately 60,000, consisting of 65% by weight of acrylic acid and 35% by weight of itaconic acid 4) Molecular placement pieces 5,5
5) Maneuverability of kneaded product (JIS T 6602 during kneading)
At the time of comprehensive evaluation, it was determined whether the product had the kinematic viscosity of standard consistency and whether the filling workability was good. ) Note 6) The powder and hardening liquid were uniformly kneaded for 1 minute, and the adhesion to gutta percha points was examined 5 minutes after the start of kneading.

Note 7: A cured product with a thickness of >2 mm was irradiated with X-rays at 80 kV and a distance of 200 m for 0.02 seconds, and the X-ray film was exposed and examined.

Note 8) A glass tube with an inner diameter of 1 mm and a length of 15 mm was filled with materials kneaded at room temperature at a standard powder-liquid ratio, and immediately immersed in a 0.6% leadamine aqueous solution in a constant temperature bath at 37°C. After one day had passed, the glass tube was removed from the dye solution, and the longest distance of the dye penetrating into the glass tube from the tip was measured. The distance is 1. , Omm or less: ○, 1
．． Those between 0 mm and 2.0 mm are marked as △, 2, and 0.
Those larger than mm are indicated by x.

Note 9) Conducted according to JIS T 6602 coagulation test.

4

Claims (1)

[Scope of Claims] (i) A powder [P] in which 2 to 12 parts by weight of magnesium oxide powder and 5 to 60 parts by weight of iodoform powder are blended with 100 parts by weight of α-tricalcium phosphate powder; (ii ) a curing liquid [L] which is a 10 to 40% by weight aqueous solution of an unsaturated carboxylic acid polymer, and the weight ratio of the above [P] and [L] [P]/[
A root canal filling material in which L] is 1.0 to 2.5.