JP6314064B2 - Method for evaluating adhesive strength of dental adhesive layer - Google Patents

Description

  The present invention relates to a method for evaluating the adhesive strength of a dental adhesive layer by a dry etching method.

  In the case of a tooth cavity damaged by caries or the like, if it is a relatively small cavity in the first mid-stage, restoration by a composite resin is performed from the viewpoint of aesthetics, simplicity of operation and quickness. On the other hand, for repairing a relatively large cavity, a restoration using a prosthesis made of metal, ceramics, or dental resin is performed.

  Since these dental restorations such as composite resins and prostheses do not have adhesiveness to the tooth, bonding materials and dental cement (dental adhesive) are used to adhere to the tooth. It is done. Bonding materials and dental cements (dental adhesives) are first used for etching hard teeth (especially in the case of enamel mainly composed of hydroxyapatite, which is particularly effective in improving the adhesion test force). Applying a treatment material (phosphoric acid etching material etc.), then called a primer on the soft tooth material exposed by the etching treatment (dentin mainly composed of organic components) and the tooth material exposed with enamel trabeculae, A pretreatment material as a penetration enhancer into the tooth or an adhesion test force improving agent is applied, and a treatment for improving the adhesion of the tooth to the bonding material or dental cement (dental adhesive) is performed in advance. In addition, for the purpose of reducing the complexity of such treatment, a two-step dental adhesive comprising a pretreatment material and a dental adhesive main material having an etching treatment and a pretreatment function at the same time, and an etching treatment A two-step dental adhesive consisting of the pretreatment material and the dental adhesive main material, or a one-step dental adhesive material (one-step bonding material or self-adhesive dental cement) having the function of the pretreatment material. Sometimes used. Furthermore, in recent years, a composite resin imparted with adhesiveness (adhesive composite resin) may be directly adhered and filled into the cavity.

  In both cases, considering the adhesion to dentin, in order to improve the adhesion of the dental adhesive to the dentin, the hard dentin is decalcified by etching treatment to form an exposed dentin collagen fiber layer. It is supposed that the penetration of the dental adhesive into the demineralized dentin is promoted by permeating the penetration promoting component. A layer in which the monomer of the dental adhesive penetrates into the demineralized dentin and is polymerized and cured is referred to as a resin-impregnated layer (also referred to as a hybrid layer). Is called an adhesive layer), and is considered to play an important role.

At present, the elucidation of the adhesion mechanism of the adhesive layer to the tooth is being promoted, and various dental adhesives suitable for the mechanism have been developed. The bond strength of the developed dental adhesive to the tooth is generally measured by a tensile strength test.
However, in order to carry out the tensile strength test, it is necessary to bond and laminate the adhesive layer and composite resin layer to the tooth, but if these treatments are not appropriate, the adhesive strength of the dental adhesive will be correct. There is a problem that cannot be evaluated. In other words, even when the dental adhesive itself has sufficient adhesive strength, there is a defect in the method of performing the bonding and laminating process (air drying time, etc.), or the bonding and laminating process itself (water If there is a deficiency in the adjustment of the wet state of the tooth surface by the addition of, the adhesive strength cannot be evaluated correctly.
Therefore, development of a method for correctly evaluating the adhesive strength specific to the material of the dental adhesive is required.
In addition, the tensile strength test is a destructive inspection, and the place where the strength is the weakest is the breaking point. Therefore, even when it is assumed that there is no significant difference in the strength of each individual adhesive layer, There is a problem that it is difficult to correctly evaluate the adhesive strength unique to the adhesive layer because the test results vary greatly between the case where the strength is weak and the case where the strength is not present. In addition, when a relatively correct evaluation is to be obtained by a tensile strength test, the test result has a large deviation. Therefore, it is necessary to produce a large number of test pieces and perform the test repeatedly.
Therefore, it is required to develop a method capable of correctly evaluating the strength of the entire adhesive layer, that is, the magnitude of the adhesive strength with a small number of test pieces and the number of tests.

By the way, the structure is elucidated by performing a dry etching process on a dental structure in which an adhesive layer and a composite resin layer are bonded and laminated on a tooth.
For example, this dental structure is cut, and the exposed laminated structure is subjected to argon ion etching, and after etching, the structural change of the resin-impregnated layer formed between the dentin and the adhesive layer is elucidated (non- Furthermore, after clarifying that the structure of the resin-impregnated layer subjected to the same etching treatment has a network structure, the components of the network structure are elucidated. (Non-Patent Document 2) has been performed.
However, although these attempts contribute to the elucidation of the structure of the resin-impregnated layer, they have not been studied as a method for evaluating the adhesive strength unique to the dental adhesive. In addition, it is disclosed that the resin-impregnated layer has a soft part having no etching resistance and a hard part having an etching resistance, but generally, the hardness and the adhesive strength are different physical properties and are soft. However, even under such a study, there is still no method for evaluating the adhesive strength specific to the dental adhesive.

Naoko Harada et al., “Etching rate of hybrid layer by argon ion etching”, Dental Materials and Instruments Vol.16 Special Issue 30, p29 (1997). Akimoto Naotake et al., “FE-SEM observation of network structure at resin-dentin adhesive interface by argon ion etching”, Adhesive Dentistry Vol.23 No.1, p34-44 (2005).

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, an object of the present invention is to provide a new method for evaluating the adhesive strength of a dental adhesive layer capable of evaluating the adhesive strength specific to the dental adhesive.

In order to solve the above-mentioned problems, the present inventors have conducted intensive studies, and the following knowledge was obtained. In other words, two types of samples for evaluation with high and low adhesive strengths were prepared in advance by clarifying the adhesive strength by a tensile strength test. When these samples were dry-etched, the dental adhesive layer was etched. It was found that there was a difference in shape.
Therefore, if the characteristics of each etching shape (etching depth) of the high and low adhesive strengths that constitute these differences are grasped, whichever characteristic when the adhesive layer of the dental structure is dry-etched Depending on whether or not appears, it becomes possible to evaluate the adhesive strength specific to the dental adhesive layer.

The present invention is based on the above knowledge, and means for solving the above problems are as follows. That is,
<1> An evaluation dentistry in which an adhesive layer and a prosthetic restoration layer are laminated in this order in a state of being adhered onto a tooth, and are cut out along the laminating direction so that the laminated state is exposed. A dry etching process in which an etching gas is uniformly introduced into at least the exposed surface of the adhesive layer and dry etching is performed on the material adhesion section, and an etching depth measurement in which the etching depth of the dry etched adhesive layer is measured. A dental adhesive layer comprising: a step, and an adhesive strength evaluation step of evaluating an adhesive strength of the prosthetic restoration layer of the adhesive layer to the tooth based on the measured etching depth Evaluation method of adhesive strength.
<2> In the adhesive strength evaluation step, when the average etching depth of the adhesive layer measured is shallower than the reference etching depth, the adhesive strength of the adhesive layer is good compared to a preset reference etching depth. The method for evaluating the adhesive strength of a dental adhesive layer according to <1>, which is a step of evaluating that the adhesive strength of the adhesive layer is poor when the depth exceeds the reference etching depth.
<3> In the adhesive strength evaluation step, when the average etching depth on the tooth side is shallower than the average etching depth on the side opposite to the tooth side as viewed from the center position in the thickness direction of the adhesive layer, The dental adhesive layer according to any one of <1> to <2>, which is a step of evaluating that the adhesive strength is good and evaluating the case where the adhesive strength is equal or deep when the adhesive layer has poor adhesive strength Evaluation method of adhesive strength.

  ADVANTAGE OF THE INVENTION According to this invention, the said various problems in a prior art can be solved, and the new adhesive strength evaluation method of the dental adhesive layer which can evaluate the adhesive strength intrinsic | native to a dental adhesive layer can be provided.

It is a conceptual diagram explaining the irradiation condition of an argon ion beam. It is a figure which shows the measurement result of the etching depth with respect to the dental material adhesion | attachment slice I for evaluation (model with favorable adhesive strength). It is a figure which shows the measurement result of the etching depth with respect to the dental material adhesion | attachment slice II for evaluation (model with favorable adhesive strength). It is a figure which shows the measurement result of the etching depth with respect to the dental material adhesion section III for evaluation (model with favorable adhesive strength). It is a figure which shows the measurement result of the etching depth with respect to the dental material adhesion | attachment slice IV for evaluation (model with a bad adhesive strength).

  The method for evaluating the adhesive strength of a dental adhesive layer of the present invention includes at least a dry etching step, an etching depth measurement step, and an adhesive strength evaluation step, and includes other steps as necessary.

(Dry etching process)
The dental adhesive layer and the prosthetic restoration layer are laminated in this order in a state where they are adhered on the tooth, and the dental material for evaluation which is cut out along the laminating direction so that these laminated states are exposed. In this step, dry etching is performed by uniformly introducing an etching gas into at least the exposed surface of the adhesive layer with respect to the adhesive slice.
The adhesive layer may be directly laminated on the tooth, but when the adhesive layer is laminated on the tooth, a resin-impregnated layer (demineralized dentin) is formed between the tooth and the tooth. When the adhesive layer forming component penetrates and hardens), the adhesive layer is indirectly laminated on the tooth through the resin impregnated layer.

-Preparation of dental material adhesive sections for evaluation-
The method for producing the evaluation dental material-bonded slice will be described.
First, there is no restriction | limiting in particular as a tooth | gear used for preparation of the said dental material adhesion | attachment slice for evaluation, According to the objective, it can select suitably, For example, commercially available bovine tooth, extraction human tooth, etc. can be used.

Next, the method of forming the adhesive layer and the prosthetic restoration layer on the tooth of the tooth is not particularly limited and can be appropriately selected depending on the purpose.
Here, the adhesive layer serving as a material for evaluating the adhesive strength by dry etching is a layer formed by polymerizing and curing a composition containing at least a polymerizable monomer, and has an adhesive property by a chemical reaction such as ionic crosslinking. Any of the layers formed by curing the composition shown corresponds to a pretreatment material as a dental pretreatment material, as well as a cured layer of a bonding material as a dental adhesive. A hardened layer of dental cement, a hardened layer of dental cement, a dental coating material, a hardened layer of an adhesive composite resin, and the like.
Hereinafter, the main method of forming the adhesive layer and the prosthetic restoration layer on the tooth of the tooth will be exemplified and described according to the configuration of the adhesive layer.

As a first method, a method using a bonding material as a material for forming the adhesive layer and a composite resin as the prosthetic restoration can be used.
For example, first, the tooth is cut out by a known method performed in dental treatment or a mock test on the tooth, and then pretreated with a known pretreatment material as necessary, and then a bonding material is prepared. An example is a method in which a composite resin as a prosthetic restoration is further applied and polymerized and cured after application and polymerization and curing.
Here, the method for scraping the tooth is not particularly limited. For example, a rotating grinder set with water-resistant abrasive paper is used to prepare a smooth ground surface of the tooth (enamel or dentin). And a method of forming a simulated cavity under water injection using a dental bar and a turbine.
Moreover, there is no restriction | limiting in particular as said pretreatment material, The well-known pretreatment material which show | plays the decalcification effect | action with respect to the said tooth | gear or an adhesive effect can be used. Moreover, the well-known pre-processing material which has the osmosis | permeation effect | action with respect to dentin can be used.
Moreover, there is no restriction | limiting in particular as said bonding material, It can select from a well-known bonding material and can make this into evaluation object. As this bonding material, a material having the function of the pretreatment material can also be used. In this case, after cutting out the tooth substance, the bonding material can be directly applied and polymerized and cured.
Moreover, there is no restriction | limiting in particular as said composite resin, The well-known composite resin used for dental treatment can be used.
When the pretreatment material containing a polymerizable monomer as an adhesive component is used, the pretreatment material cured layer, the bonding material cured layer, and the composite resin cured layer are formed on the tooth. Are laminated in this order, and a laminate of the cured layer of the pretreatment material and the cured layer of the bonding material can be used as one adhesive layer for evaluation of adhesive strength. In this case, each of the cured layer of the pretreatment material and the cured layer of the bonding material can be regarded as one adhesive layer, and the adhesive strength of these layers alone can be evaluated.

As a 2nd method, the method using the dental cement as a formation material of the said contact bonding layer and the dental prosthesis as the said prosthetic restoration is mentioned.
For example, first, the tooth is cut out with respect to the teeth by the above-described method performed in dental treatment or a simulation test. At the same time, using the dental prosthesis as the prosthetic restoration, the dental prosthesis is prepared so as to be compatible with the shaved tooth material. Next, if necessary, after pretreatment of at least one of the tooth and the dental prosthesis with a known pretreatment material, the dental cement is applied to at least one of the tooth and the dental prosthesis. There is a method in which the dental cement and the dental prosthesis are pressure-bonded through the dental cement, and the dental cement is cured.
Here, the method for preparing the dental prosthesis is not particularly limited. For example, by using a conventionally known method, an impression of a cavity of the cavity formed in the tooth is taken, and the protrusion is adapted to the recess. Examples thereof include a method for preparing the dental prosthesis, a method for preparing a smooth ground surface of the dental prosthesis using a rotary polishing machine on which water-resistant abrasive paper is set, and using this as the adherend surface.
Moreover, there is no restriction | limiting in particular as said pretreatment material, The well-known pretreatment material which show | plays the decalcification effect | action with respect to a tooth | gear, and the adhesion effect | action with respect to a tooth | gum or a dental prosthesis can be used as needed. Moreover, the well-known pretreatment material which has the osmosis | permeation effect | action with respect to dentin can be used.
Moreover, there is no restriction | limiting in particular as said dental cement, It can select from well-known dental cement and can make this into evaluation object. As this dental cement, a type having the function of the pretreatment material can also be used. In this case, the dentine and the dental prosthesis can be cured after being crimped without pretreatment. The dental cement is of a type that is polymerized and cured by photopolymerization, a type that is polymerized and cured by chemical polymerization, and a type that is cured by forming ionic crosslinks such as glass ionomer cement in addition to these polymerized and cured types. Includes everything.
Moreover, there is no restriction | limiting in particular as said dental prosthesis, The well-known prosthetic material comprised from the metal used for dental treatment, ceramics, and a dental resin can be used.
In addition, when using what contains the said polymerizable monomer as an adhesive component as said pre-processing material, the hardened layer of the said pre-processing material (for the said dentine) on the said dentine, the said dental cement A hardened layer, a hardened layer of the pretreatment material (for the dental prosthesis), and a hardened layer of the dental prosthesis are laminated in this order. The hardened layer of each pretreatment material and the dental A laminate of hardened cement cement layers can be used as one of the adhesive layers to be evaluated for adhesive strength. In this case, each of the hardened layer of each pretreatment material and the hardened layer of the dental cement can be regarded as one adhesive layer, and the adhesive strength of these layers alone can be evaluated.

As a third method, a method using a dental coating material or an adhesive composite resin as a material for forming the adhesive layer and the prosthetic restoration can be used. Each hardened layer of the dental coating material and the adhesive composite resin serves as the adhesive layer and the prosthetic restoration layer.
For example, first, the tooth is cut out with respect to the teeth by the above-described method performed in dental treatment or a simulation test. Next, if necessary, after a pretreatment with a known pretreatment material, a dental coating material is applied and polymerized and cured, and a dental coating material layer is adhered and formed on the tooth surface.
In this case, the dental coating material layer serves as the adhesive layer and the prosthetic restoration layer, but the dental coating has a thickness of 5 μm to 500 μm which is a general thickness of the formed dental coating material layer. When the material layer was formed, according to the study by the present inventors, a dental coating material layer (polymerizable single layer as an adhesive component) generally having a height of 0.1 μm to 100 μm, preferably 1 μm to 50 μm from the tooth. A cured layer of the pretreatment material containing a polymer is also considered as the adhesive layer as a layer contributing to adhesion to the tooth, and the other dental coating material layer portion Can be regarded as the prosthetic restoration layer. In some cases, the hardened layer of the pretreatment material when pretreatment is performed may be regarded as the adhesive layer, and the dental coating material layer may be regarded as the prosthetic restoration layer.
Similarly, in the case of using the adhesive composite resin, the tooth is cut out by the above-described method performed in dental treatment or a mock test for the tooth, and then a known pretreatment is performed if necessary. After the pretreatment with the material, the adhesive composite resin is applied and polymerized and cured to bond and form the adhesive composite resin layer on the tooth surface.
In this case, the adhesive composite resin layer serves as the adhesive layer and the prosthetic restoration layer, but the adhesive composite resin layer has a thickness of 100 μm to 10,000 μm, which is a general thickness of the formed adhesive composite resin layer. When the adhesive composite resin layer is formed, according to the study by the present inventors, the adhesive composite resin layer (adhesive component as an adhesive component) is approximately 0.1 μm to 100 μm, preferably 1 μm to 50 μm in height from the tooth. If the pretreatment material layer obtained by curing the pretreatment material containing a polymerizable monomer is formed, this is also considered) as a layer that contributes to adhesion to the dentine, The adhesive composite resin layer portion other than can be regarded as the prosthetic restoration layer. In some cases, the hardened layer of the pretreatment material when pretreatment is performed may be regarded as the adhesive layer, and the adhesive composite resin layer may be regarded as the prosthetic restoration layer.
There is no restriction | limiting in particular as said pre-processing material, The well-known pre-processing material which show | plays the decalcification effect | action with respect to a tooth | gear or an adhesive effect can be used as needed. Moreover, the well-known pre-processing material which has the osmosis | permeation effect | action with respect to dentin can be used.
Moreover, there is no restriction | limiting in particular as said dental coating material (a sealing material, a coating material, a hypersensitivity suppression material, etc.), It can select from a well-known dental coating material and can make this into evaluation object. As the dental coating material, a material having the function of the pretreatment material can also be used. In this case, the dental coating material can be directly applied and polymerized and cured after carving out the tooth.
Moreover, there is no restriction | limiting in particular as said adhesive composite resin, The well-known adhesive composite resin (it is also called self-adhesive composite resin) used for dental treatment can be used.

  The bonding material, pretreatment material, dental cement, dental coating material, adhesive composite resin, and the like as the adhesive layer forming material are made of various conventionally known materials that form a solid or gel adhesive layer after curing. Contains various ingredients. These components generally include organic fillers such as polymethyl methacrylate and crosslinked polymethyl methacrylate, various polymers dissolved in the forming material, silica, silica zirconia, zirconium oxide, alumina, barium glass, fluoroaluminosilicate. Examples thereof include inorganic fillers such as glass and conventionally known polymerizable monomers that form an adhesive layer after polymerization and curing. In addition, the forming material may be a conventionally known chemical polymerization initiator, photopolymerization initiator, polymerization initiation assistant, polymerization inhibitor, pigment, dye, fragrance, organic acid, inorganic acid, water, alcohol or other organic material as necessary. Inorganic salts such as solvents, surfactants and sodium fluoride are included.

Here, in the case where the adhesive layer contains approximately 90 wt% or more of the inorganic fillers, if the inorganic fillers are difficult to be dry etched, the inorganic fillers physically hinder the dry etching action in the depth direction. Therefore, the etching depth becomes relatively small, and it may be difficult to detect a difference in etching depth between a plurality of forming materials.
From such a viewpoint, the content of the inorganic filler contained in the adhesive layer is preferably 85 wt% or less, more preferably 70 wt% or less, and particularly preferably 60 wt% or less. For example, when the above-mentioned bonding material, pretreatment material or dental coating material contains the polymerizable monomer, the adhesive layer may be air blown with a solvent or water as required according to the recommended technique of the forming material. The inorganic fillers are usually contained in an amount of 60 wt% or less, which is preferable as a forming material used in the adhesive strength evaluation method of the present invention. On the other hand, as an adhesive layer prepared from the aforementioned dental cement (excluding its pretreatment agent) or an adhesive composite resin, it usually contains 60 wt% or more and less than 85 wt% of the above inorganic fillers. It can be said that the pretreatment material or the dental coating material is a more preferable application mode in comparison.
As the content of the inorganic fillers in these adhesive layers, referring to the composition of the forming material, if necessary, from the amount of the inorganic fillers in the residue after subtracting the reduced amount of the organic solvent and water by air blow Can be calculated. Alternatively, the inorganic fillers are isolated from the forming material by filtration, centrifugation, etc., and weighed, and if necessary, calculated as the inorganic filler content in the residue after subtracting the reduced amount of organic solvent and water by air blow You can also. For example, a cured product prepared by air blowing the forming material as a forming material to reduce the amount of solvent and water and then polymerizing and curing is generally 0 to 40 wt% of the inorganic fillers and 40 wt% to 99 wt%. In general, the polymerizable monomer contains 5 wt% or less of a polymerization initiator, a polymerization co-catalyst, other additives, a residual solvent, and residual water (however, the total content thereof is adjusted to 100 wt%). )

The evaluation dental material adhesive section is used by cutting out along the stacking direction from the state where the adhesive layer and the prosthetic restoration layer are stacked so that the stacked state is exposed.
If it is possible to cut out in such a state, the cutting method is not particularly limited, and a known cutting device such as a cutting machine such as a diamond cutter or a grinding machine such as a dental bar or a dental CAM should be used. Can do.
Further, the notch may be performed so that the entire laminated state of the adhesive layer and the prosthetic restoration layer is exposed, or may be performed so that only the adhesive layer is exposed.
The exposed surface exposed after the notch is preferably mirror-like polished with a known abrasive from the viewpoint of accurately evaluating the etching depth.

-Dry etching-
There is no restriction | limiting in particular as the implementation method of the said dry etching, According to the objective, it can select suitably, It can implement by the well-known plasma etching method and the well-known ion etching method. Examples of the etching gas used for the dry etching include inert gas, oxygen gas, halogen compound gas, hydrocarbon gas, hydrogen gas, or ions or radicals using these gases as source gases.
Among these, ion etching using argon ions is preferable.
A method for uniformly introducing the etching gas into the exposed surface is not particularly limited, and a method for introducing the etching gas with a uniform output from a direction orthogonal to the exposed surface, or a direction of introducing the etching gas. In the case where the exposed surface is tilted from the orthogonal direction, a method of introducing the etching gas while rotating the center of the exposed surface about the introduction direction of the etching gas as an axis can be cited.
In addition, since the dry etching evaluates the adhesive strength of the adhesive layer based on the etched shape of the exposed surface etched, a part of the dry etching without etching the entire laminated structure including the adhesive layer is performed. It is preferable to carry out the etching under conditions (for example, the surface of the exposed surface).

(Etching depth measurement process)
The etching depth measuring step is a step of measuring the etching depth of the dry-etched adhesive layer.
The method for evaluating the adhesive strength of the dental adhesive layer of the present invention utilizes the fact that the etching shape is different between the adhesive layer having a high adhesive strength and the adhesive layer having a low adhesive strength. The etching shape is performed by measuring the etching depth.

There is no restriction | limiting in particular as a measuring apparatus which measures the said etching depth, For example, a well-known laser microscope can be used.
Further, the measurement target of the etching depth is not limited to the entire exposed surface of the dry-etched adhesive layer, but may be a part thereof. For example, the exposed surface may be scanned linearly along the stacking direction, and measurement at the scanned portion may be performed.

(Adhesive strength evaluation process)
The adhesive strength evaluation step is a step of evaluating the adhesive strength of the prosthetic restoration layer of the adhesive layer to the tooth based on the measured etching depth.
The method for evaluating the adhesive strength of the dental adhesive of the present invention utilizes the fact that the etching shape is different between the adhesive layer having a high adhesive strength and the adhesive layer having a low adhesive strength.
The etching shape (the etching depth) used for the evaluation is not particularly limited as long as it is a shape that makes a difference between the adhesive layer having a high adhesive strength and the adhesive layer having a low adhesive strength. Here, the first evaluation method and the second evaluation method will be described as examples of the adhesive strength evaluation method.

First, in the first evaluation method, when the average etching depth of the adhesive layer measured is shallower than the reference etching depth, the adhesive strength of the adhesive layer is lower than the preset reference etching depth. In this method, the adhesive layer is evaluated as being good, and when the depth exceeds the reference etching depth, the adhesive strength of the adhesive layer is evaluated as poor.
That is, there is a difference in the etching depth between the adhesive layer having a high adhesive strength and the adhesive layer having a low adhesive strength, and the adhesive layer having a lower adhesive strength is formed in the adhesive layer having a higher adhesive strength. The etching depth tends to be shallower than the layer.
Accordingly, if the etching depth of the adhesive layer having a structure with high adhesive strength is set in advance as the reference etching depth, the adhesive strength is high when the etching depth is shallower than the reference etching depth. On the contrary, when it is deep, it can be evaluated that the adhesive strength is low.
Thus, it was a surprising discovery for the present inventors that the etching depth correlates with the adhesive strength. As the reason for this, the present inventors consider as follows. In other words, the destructive inspection in the adhesive strength measurement test is a test that breaks the chemical interaction between atoms and molecules such as polymer chain entanglement, ionic bond, covalent bond, hydrogen bond, etc. by physical load when viewed at the molecular level. is there. The dry etching process chemically causes such a destructive action, and therefore, the etching depth and the adhesive strength are well correlated.

Next, the second evaluation method is a case where the average etching depth on the tooth side is shallower than the average etching depth on the opposite side to the tooth side when viewed from the center position in the thickness direction of the adhesive layer. In this method, the adhesive strength of the adhesive layer is evaluated as good, and the case where the adhesive layer is deep is evaluated as poor in the adhesive strength.
That is, in the adhesive layer having a structure with high adhesive strength, the average etching depth on the tooth side is shallower than the average etching depth on the opposite side to the tooth side when viewed from the center position in the thickness direction of the adhesive layer. On the contrary, in the adhesive layer having a structure with low adhesive strength, the average etching depth on the tooth side as viewed from the center position in the thickness direction of the adhesive layer is the average on the side opposite to the tooth side. There is a tendency to be equal to or deeper than the etching depth.
Therefore, when the average etching depth on the tooth side as viewed from the center position in the thickness direction of the adhesive layer is shallower than the average etching depth on the side opposite to the tooth side, the adhesive strength of the adhesive layer is good. It can be evaluated that there is, and conversely, it can be evaluated that the adhesive strength of the adhesive layer is poor when it is equal or deep.
In this case, the adhesive layer having a structure with high adhesive strength also tends to gradually decrease the etching depth of the adhesive layer from the side opposite to the dentin side toward the dentin side. In addition, such a tendency is not confirmed in the adhesive layer having a structure with low adhesive strength.
Therefore, when the etching depth of the adhesive layer gradually decreases from the side opposite to the tooth side toward the tooth side, it is evaluated that the adhesive strength of the adhesive layer is good, and conversely, it does not become shallow. In some cases, it can be evaluated that the adhesive strength of the adhesive layer is poor. Specifically, the exposed surface of the adhesive layer is scanned linearly along the laminating direction, and the measurement result of the obtained etching depth is determined as the position of the adhesive layer in the laminating direction and the position. The slope of the approximate straight line (or the shape of the approximate curve) obtained by plotting the etching depth on the XY plane with the X-axis and the Y-axis as the X-axis and the Y-axis is directed from the opposite side to the tooth side. Thus, the adhesive strength of the adhesive layer can be evaluated based on whether or not the etching depth of the adhesive layer tends to become gradually shallower.
Thus, it was a surprising discovery for the present inventors that the inclination of the approximate straight line of the etching depth (or the shape of the approximate curve) correlates with the adhesive strength. As the reason for this, the present inventors consider as follows. That is, when the etching depth of the adhesive layer becomes shallower from the side opposite to the tooth side toward the tooth side, the physical / chemical relationship with the component derived from the tooth in the adhesive layer. Due to the interaction, the quality of the adhesive layer is improved toward the tooth side, and the etching resistance is acquired and the adhesive strength is improved. This is because, for example, the number of chemical bonds increases due to the interaction between ionic species (calcium, etc.) generated by decalcification of the tooth and components in the dental adhesive (ionic compounds such as acidic monomers). The adhesion layer improves the quality, acquires etching resistance and improves the adhesive strength, strengthens the hydrogen bond and ionic bond due to the increase of water from the tooth, and the initiator activity ability by water and ionic species This is due to the improvement of the entanglement, the entanglement with the collagen fibers of the tooth, and the like.

  In addition, although the said 1st evaluation method and the said 2nd evaluation method can also each be employ | adopted as an independent evaluation method, they can also be employ | adopted as a 3rd evaluation method which used these together. For example, even if it is evaluated as good by the first evaluation method, if it is evaluated as defective by the second evaluation method, one of them is evaluated as defective and evaluated as defective. You can also. On the contrary, even in the above-described case, it can be evaluated that one of them is good.

(Other processes)
The other steps are not particularly limited as long as the effects of the present invention are not hindered, and various steps can be performed by appropriately selecting according to the purpose.
Below, in order to demonstrate this invention concretely, an Example and a comparative example are given and demonstrated, However, The technical idea of this invention is not restrict | limited at all by these.

(Preparation of dental material adhesive section for evaluation)
<Evaluation Dental Material Adhesive Section I>
First, the front teeth of the cow were removed within 24 hours after slaughtering, and the dentin plane was cut out with a # 600 emery paper so as to be parallel to the labial surface under the water. Here, the cutting is performed until reaching the deep dentin from the enamel of the surface layer, and when the dental adhesive composition described later is applied, the resin impregnated layer is formed by penetrating into the dentin. I made it.
The surface that had been shaved was washed with water, dried by blowing compressed air on the dentin plane for about 10 seconds, applied with a 39 wt% phosphoric acid aqueous solution, and washed again with water to deash the surface.
Next, after the compressed air is blown onto the dentin plane for about 10 seconds and dried, a double-sided tape with a 3 mm diameter circular hole is fixed, and then a paraffin wax with a 0.5 mm thick and 8 mm diameter circular hole is opened. A simulated cavity was formed by fixing the double-sided tape to the same center on the circular hole.
In this simulated cavity, a dental adhesive composition (Tokuyama Dental Co., Ltd., Tokuyama Bond Force II) that etches the dentin and forms an adhesive layer by photopolymerization is applied and left for 20 seconds. The spray was dried for about 10 seconds and dried, and irradiated with light for 10 seconds using a dental visible light irradiator (Tokuso Power Light, manufactured by Tokuyama Corporation).
Further, a dental composite resin (Esterite Flow Quick, manufactured by Tokuyama Dental Co., Ltd.) that forms a composite resin layer by photopolymerization was filled thereon, and irradiated with light by a dental visible light irradiator for 30 seconds.
Thereby, the adhesive layer and the composite resin layer were bonded in this order on the tooth and laminated. At this time, a resin-impregnated layer is formed between the tooth and the adhesive layer.
Next, notches are formed along the laminating direction so as to expose these laminated states, and the exposed surface is polished like a mirror surface using diamond slurry (manufactured by Engis Co., Ltd., high press diamond slurry, 0.25 μm) (dry etching). Process pretreatment).
As described above, an evaluation dental material adhesive slice I was prepared.

<Section I for Adhesive Strength Test>
In preparation of the dental material adhesive slice I for evaluation, decalcification with an aqueous phosphoric acid solution was not performed, and after bonding and laminating an adhesive layer and a composite resin layer on the tooth in this order, for the dry etching step An adhesive strength test section I was prepared in the same manner as the preparation of the evaluation dental material adhesive section I except that the pretreatment was not performed.

Dental material adhesion section I for evaluation is a dental adhesive composition with excellent adhesive strength (Tokuyama Dental Co., Ltd., Tokuyama Bond Force II, SR monomer as an adhesive monomer, as a model with good adhesive strength of the adhesive layer. Contained). The SR monomer is an adhesive monomer described in technical documents of Tokuyama Dental Co., Ltd., which is composed of a substance called key material and a plurality of phosphate ester monomer molecules to form a polyfunctional monomer-like structure. It is.
Actually, in section I for adhesion strength test created using this composition, it was pulled at a crosshead speed of 2 mm / min using a tensile tester (Autograph, manufactured by Shimadzu Corp.), and the tension of the tooth and the composite resin was pulled. The test for measuring the adhesive strength was carried out on four pieces of adhesive strength test sections I per test, and the average value thereof was calculated. As a result, the tensile adhesive strength was 19 MPa, and the adhesive strength was excellent.

<Dental material adhesive section II for evaluation>
Preparation of evaluation dental material adhesive section I, except that the dental adhesive composition used was changed from Tokuyama Bond Force II to Tokuyama Dental Co., Ltd., Tokuyama Bond Force in preparation of evaluation dental material adhesive section I Similarly, a dental material adhesion section II for evaluation was prepared.

<Section II for adhesive strength test>
In the preparation of the adhesive strength test section I, the dental adhesive composition used was the same as the preparation of the evaluation dental material adhesive section I except that the dental adhesive composition used was changed from Tokuyama Bond Force II to Tokuyama Dental Co., Ltd., Tokuyama Bond Force. Thus, a section II for adhesive strength test was prepared.

The dental material adhesive section II for evaluation is a dental adhesive composition with excellent adhesive strength (Tokuyama Dental Force, Tokuyama Bond Force, Tokuyama Bond Force as an adhesive monomer, as a model with good adhesive strength of the adhesive layer. Containing SR monomer different from II).
Actually, in the section II for adhesive strength test created using this composition, the tensile tester (Autograph, manufactured by Shimadzu Corporation) was used to pull at a crosshead speed of 2 mm / min, and the tooth and composite resin were pulled. The test for measuring the adhesive strength was carried out on four adhesive strength test sections II per test, and when the average value was calculated, the tensile adhesive strength was 19 MPa, indicating excellent adhesive strength.

<Evaluation Dental Material Adhesive Section III>
In the preparation of the dental material adhesive section I for evaluation, the dental adhesive composition I of the evaluation dental material adhesive section I was used except that the dental adhesive composition used was changed from Tokuyama Bond Force II to Scotch Bond Universal Adhesive. Dental material adhesion section III for evaluation was produced in the same manner as the production.

<Section III for adhesive strength test>
Preparation of the adhesive material test section I for evaluation except that the dental adhesive composition used was changed from Tokuyama Bond Force II to Scotch Bond Universal Adhesive in the preparation of the adhesive strength test section I. In the same manner as above, a section III for adhesion strength test was prepared.

The dental material adhesive section III for evaluation is a dental adhesive composition having excellent adhesive strength (model 3M, Scotchbond Universal Adhesive, 10- Methacryloyloxydecyl dihydrogen phosphate).
Actually, in the section III for bond strength test prepared using this composition, the tensile tester (Autograph, manufactured by Shimadzu Corp.) was used to pull at a crosshead speed of 2 mm / min, and the tooth and composite resin were pulled. The test for measuring the adhesive strength was carried out on four pieces of adhesive strength test sections III per test, and the average value thereof was calculated. As a result, the tensile adhesive strength was 16 MPa, which showed excellent adhesive strength.

<Evaluation Dental Material Adhesive Section IV>
In preparation of the dental material adhesive slice I for evaluation, the dental adhesive composition used was from Tokuyama Bond Force II except that a phosphate ester monomer was blended instead of the SR monomer as an adhesive monomer. An evaluation dental material adhesive section IV was prepared in the same manner as the preparation of the evaluation dental material adhesive section I except that the composition was prepared in the same manner as described above.

<Section IV for adhesive strength test>
In the preparation of the adhesive strength test section I, the dental adhesive composition used was from Tokuyama Bond Force II except that a phosphate ester monomer was blended instead of the SR monomer as an adhesive monomer. An adhesive strength test section IV was prepared in the same manner as the preparation of the evaluation dental material adhesive section I except that the composition was similarly prepared.

The dental material adhesion section IV for evaluation is a model in which the adhesive strength of the adhesive layer is poor, the adhesive strength is inferior to Tokuyama Bond Force II, except that the phosphate monomer is blended instead of the SR monomer as the adhesive monomer Is formed using a composition prepared in the same manner as Tokuyama Bond Force II.
Actually, in the section IV for the adhesive strength test prepared using this composition, the tensile tester (Autograph, manufactured by Shimadzu Corporation) was used to pull at a crosshead speed of 2 mm / min, and the tooth and composite resin were pulled. The test for measuring the adhesive strength was carried out on four pieces of adhesive strength test sections IV per test, and the average value was calculated. The tensile adhesive strength was 12 MPa, and the adhesive strength test section IV was The adhesive strength was lower than the adhesive strength test sections I, II, and III as a model in which the adhesive strength of the adhesive layer was good.

Example 1
<Dry etching process>
Using an ion etching apparatus (manufactured by Hitachi High-Technologies Corporation, IM4000), dry etching was performed by uniformly introducing an etching gas onto the exposed surface of the evaluation dental material adhesion section I on the evaluation dental material adhesion section I. . Here, argon ions are used as the etching gas.
Specifically, the dental material adhesion section I for evaluation was placed in the reaction vessel of the ion etching apparatus, and argon ion etching was performed under the irradiation condition of the argon ion beam shown in FIG. As other irradiation conditions, the acceleration voltage was 2.0 kV, the ion current was 0.12 mA, and the irradiation time was 20 minutes. FIG. 1 is a conceptual diagram for explaining an irradiation state of an argon ion beam. Reference numeral 1 indicates an evaluation dental material adhesion section irradiated with an argon ion beam, and reference numeral 2 indicates an exposed surface. .

<Etching depth measurement process>
Next, the etching depth in the exposed surface of the dental material adhesive slice for evaluation I that was dry-etched was measured using a laser microscope (VK-8700 / 8710 manufactured by Keyence Corporation).
Specifically, the etching depth was measured by measuring the etching depth in a direction orthogonal to the exposed surface with reference to the position of the exposed surface before etching measured in advance.
Further, in order to derive each etching depth in each layer constituting the evaluation dental material bonding section I, the measurement of the etching depth is performed along the stacking direction over the respective layers on the exposed surface before and after dry etching. The laser was scanned linearly.
FIG. 2 shows the measurement results of the etching depth with respect to the evaluation dental material adhesion section I (model having good adhesion strength). In FIG. 2, “D” represents a dentin layer, “Hy” represents a resin-impregnated layer, “BD” represents an adhesive layer, and “CR” represents a composite resin layer.
Here, regarding the adhesive layer (BD) to be evaluated for adhesive strength, as shown in FIG. 2, the etching depth is the resin-impregnated layer (Hy) on the exposed surface after the dry etching step is performed. The position immediately before becoming deeper and deeper toward the boundary is defined as the boundary with the resin impregnated layer (Hy), and the position immediately before the etching depth becomes shallower toward the composite resin layer (CR) is defined as the composite resin layer ( CR).

(Example 2)
In Example 1, except that evaluation dental material adhesive section I (model with good adhesive strength) was replaced with evaluation dental material adhesive section II (model with different dental adhesive composition but good adhesive strength). In the same manner as in Example 1, the etching step and the etching depth measurement step were performed.
FIG. 3 shows the measurement results of the etching depth for the dental material adhesion section II for evaluation (a model in which the dental adhesive composition is different but the adhesive strength is good). In FIG. 3, “D” indicates a dentin layer, “Hy” indicates a resin-impregnated layer, “BD” indicates an adhesive layer, and “CR” indicates a composite resin layer.
Here, regarding the adhesive layer (BD) to be evaluated for adhesive strength, as shown in FIG. 3, the etching depth on the exposed surface after the dry etching step is the resin-impregnated layer (Hy). The position immediately before becoming deeper and deeper toward the boundary is defined as the boundary with the resin impregnated layer (Hy), and the position immediately before the etching depth becomes shallower toward the composite resin layer (CR) is defined as the composite resin layer ( CR).

(Example 3)
In Example 1, except that the evaluation dental material adhesive section I (model with good adhesive strength) was replaced with the evaluation dental material adhesive section III (model with different dental adhesive composition but good adhesive strength). In the same manner as in Example 1, the etching step and the etching depth measurement step were performed.
FIG. 4 shows the measurement results of the etching depth for the dental material adhesion section III for evaluation (a model in which the dental adhesive composition is different but the adhesive strength is good). In FIG. 4, “D” represents a dentin layer, “Hy” represents a resin-impregnated layer, “BD” represents an adhesive layer, and “CR” represents a composite resin layer.
Here, regarding the adhesive layer (BD) to be evaluated for adhesive strength, the etching depth on the exposed surface after the dry etching step is as shown in FIG. 4 with the resin-impregnated layer (Hy). The position immediately before becoming deeper and deeper toward the boundary is defined as the boundary with the resin impregnated layer (Hy), and the position immediately before the etching depth becomes shallower toward the composite resin layer (CR) is defined as the composite resin layer ( CR).

Example 4
In Example 1, the same procedure as in Example 1 was performed except that the evaluation dental material adhesive section I (model with good adhesive strength) was replaced with the evaluation dental material adhesive section IV (model with poor adhesive strength). The etching step and the etching depth measurement step were performed.
The measurement result of the etching depth with respect to the dental material adhesion section IV for evaluation (a model with poor adhesion strength) is shown in FIG. In FIG. 5, “D” indicates a dentin layer, “Hy” indicates a resin-impregnated layer, “BD” indicates an adhesive layer, and “CR” indicates a composite resin layer.
Here, regarding the adhesive layer (BD) to be evaluated for adhesive strength, the etching depth on the exposed surface after the dry etching step is as shown in FIG. 5 with the resin-impregnated layer (Hy). The position immediately before becoming deeper and deeper toward the boundary is defined as the boundary with the resin impregnated layer (Hy), and the position immediately before the etching depth becomes shallower toward the composite resin layer (CR) is defined as the composite resin layer ( CR).

<Adhesive strength evaluation process>
Next, the adhesive strength of the adhesive layer to the tooth through the resin-impregnated layer is evaluated based on the measured etching depth. Here, first, an evaluation method of the adhesive strength is examined based on the measurement results of FIGS. 2, 3, 4, and 5.

As shown in FIG. 2, in the evaluation dental material adhesion section I (model with good adhesion strength), the average etching depth of the adhesive layer was 2.0 μm.
Moreover, in the dental material adhesion section II for evaluation (model with good adhesive strength), as shown in FIG. 3, the average etching depth of the adhesive layer was 1.9 μm.
Moreover, in the dental material adhesion section III for evaluation (a model with good adhesive strength), as shown in FIG. 4, the average etching depth of the adhesive layer was 2.0 μm.
On the other hand, as shown in FIG. 5, in the evaluation dental material adhesion section IV (model with poor adhesion strength), the average etching depth of the adhesive layer was 2.5 μm.
Thus, there is a difference in the etching depth by dry etching between the model with good adhesive strength and the model with poor adhesive strength, and the model with good adhesive strength has a higher etching depth than the model with poor adhesive strength. Was confirmed to be shallow.
Therefore, as a result of performing the dry etching process on the arbitrarily prepared evaluation dental material adhesive slice, the average etching depth of the adhesive layer is, for example, the evaluation dental material adhesive slice I (model with good adhesive strength). If the average etching depth is 2.0 μm or less, it can be evaluated that the adhesive strength is good even in the evaluation dental material adhesive section, and on the other hand, if it exceeds 2.0 μm, It can be evaluated that the adhesive strength is poor.

From the above examination, as a first evaluation method, the adhesive strength evaluation step is performed when the measured average etching depth of the adhesive layer is shallower than the reference etching depth compared to the preset reference etching depth. Is evaluated that the adhesive strength of the adhesive layer is good, and when the depth exceeds the reference etching depth, the adhesive strength of the adhesive layer is evaluated as poor.
The specific reference etching depth can be appropriately set according to the output of the dry etching apparatus to be used. However, in the irradiation conditions of the argon ion beam in Examples 1 to 4 using the ion etching apparatus. For example, the average etching depth of the adhesive layer in the evaluation dental material adhesive sections I and III can be set to 2.0 μm.

In the evaluation dental material adhesion section I (model with good adhesion strength), as shown in FIG. 2, the average etching on the tooth side as seen from the center position in the thickness direction of the adhesive layer (horizontal axis direction in the figure). While the depth is 1.6 μm, the average etching depth on the side opposite to the tooth side is 2.4 μm, and the adhesive layer is approximately from the side opposite to the tooth side toward the tooth side. The etching depth of the film showed a tendency to become shallow.
Moreover, in the dental material adhesion section II for evaluation (a model with good adhesive strength), as shown in FIG. 3, as viewed from the center position in the thickness direction (horizontal axis direction in the figure) of the adhesive layer, While the average etching depth is 1.6 μm, the average etching depth on the side opposite to the tooth side is 2.1 μm, and approximately from the side opposite to the tooth side toward the tooth side, The etching depth of the adhesive layer tended to be shallow.
Moreover, in the dental material adhesion section III for evaluation (a model with good adhesive strength), as shown in FIG. 4, as viewed from the center position in the thickness direction (horizontal axis direction in the figure) of the adhesive layer, While the average etching depth is 1.9 μm, the average etching depth on the side opposite to the tooth side is 2.0 μm, and approximately from the side opposite to the tooth side toward the tooth side, The etching depth of the adhesive layer tended to be shallow.
On the other hand, in the dental material adhesion section IV for evaluation (model with poor adhesion strength), as shown in FIG. 5, the tooth quality is seen from the center position in the thickness direction of the adhesive layer (horizontal axis direction in the figure). The average etching depth on the side is 2.6 μm, while the average etching depth on the side opposite to the dentine side is 2.5 μm, as shown in FIGS. From the above, the tendency of the etching depth of the adhesive layer to decrease toward the tooth was not confirmed.
In addition, the center position in the thickness direction of the adhesive layer (stacking direction of the adhesive layer) is the adhesive layer and other layers (the resin-impregnated layer and the composite resin layer) on the exposed surface after the dry etching step is performed. The thickness of the adhesive layer was specified based on the boundary between the thickness and the thickness of the adhesive layer, and the thickness was determined to be half.

From the above examination, as a second evaluation method, the average etching depth on the tooth side as viewed from the center position in the thickness direction of the adhesive layer is shallower than the average etching depth on the opposite side to the tooth side. Examples include a method in which the adhesive strength of the adhesive layer is evaluated as good, and a case where the adhesive strength is equal or deep is evaluated as poor.
That is, as a result of carrying out the dry etching process on the arbitrarily prepared dental material adhesive section for evaluation, the average etching depth on the tooth side as viewed from the center position in the thickness direction of the adhesive layer is It can be evaluated that the adhesive strength of the adhesive layer is good if it is shallow compared to the average etching depth on the opposite side, and the adhesive strength of the adhesive layer is poor if it is equivalent or deep. Can be evaluated.
Further, as shown in FIGS. 2, 3, and 4, the etching depth of the adhesive layer gradually decreases from the side opposite to the tooth side toward the tooth side (shown in the figure, If the tendency that the line indicating the etching depth characteristics of the adhesive layer generally rises to the left) is confirmed, it can be more reliably evaluated that the adhesive strength of the adhesive layer is good. If the tendency is not confirmed, it can be more reliably evaluated that the adhesive strength of the adhesive layer is poor.

1 Dental material adhesive slice for evaluation 2 Exposed surface

Claims (3)

The adhesive layer and the prosthetic restoration layer are laminated in this order in a state of being adhered on the tooth, and the evaluation dental material adhesive section cut out along the laminating direction so that the laminated state is exposed. On the other hand, at least a dry etching step of performing dry etching by uniformly introducing an etching gas onto the exposed surface of the adhesive layer;
An etching depth measuring step for measuring an etching depth of the adhesive layer that has been dry-etched;
Based on the measured etching depth, an adhesive strength evaluation step for evaluating the adhesive strength of the prosthetic restoration layer of the adhesive layer with respect to the tooth,
A method for evaluating the adhesive strength of a dental adhesive layer, comprising:   The adhesion strength evaluation step evaluates that the adhesion strength of the adhesive layer is good when the measured average etching depth of the adhesive layer is shallower than the reference etching depth, compared to a preset reference etching depth. The method for evaluating the adhesive strength of a dental adhesive layer according to claim 1, which is a step of evaluating that the adhesive strength of the adhesive layer is poor when the depth exceeds the reference etching depth.   In the adhesive strength evaluation step, when the average etching depth on the tooth side as viewed from the center position in the thickness direction of the adhesive layer is shallower than the average etching depth on the opposite side to the tooth side, the adhesive strength of the adhesive layer is The method for evaluating the adhesive strength of a dental adhesive layer according to any one of claims 1 to 2, which is a step of evaluating that the adhesive strength of the adhesive layer is poor when it is evaluated as being good and being equal or deep.