In dental clinics, composite resin restoration in which a caries caused in a tooth is removed to form a cavity to be thereafter filled with a resin-based filling/restoring material is widely used. The composite resin restoration is characterized by reproducing an aesthetic state similar to that of the natural teeth and allowing a treatment to be completed with only one dental visit to reduce a burden on the patient. In order to achieve aesthetic restoration, it is important to match the color tone and the transparency of the resin-based filling/restoring material with those of teeth. The teeth have a high transparency and a light color tone at incisal ends, but have a low transparency and a dark color tone at neck portions and root portions. In order to aesthetically restore, using the resin-based filling/restoring material, various portions of the teeth with different transparencies and color tones as mentioned above, it is necessary to appropriately control the color tone and the transparency of the resin-based filling/restoring material. In general, the color tone and the transparency of the resin-based filling/restoring material are controlled by adjusting the amount of an additive such as a pigment contained in the resin-based filling/restoring material. For example, Patent Document 1 proposes an adjustment method in which a composite resin is caused to express translucency using an opalescent filler.
The resin-based filling/restoring material itself is not adhesive to teeth. Therefore, restoration with the material inevitably requires application of a dental adhesion system. The dental adhesion system acts on the enamel and the dentin of the teeth to be interposed between the resin-based filling/restoring material and the teeth to stably bond the material and the teeth to each other. Two types of dental adhesion systems are currently available in the market: one (a total-etching dental adhesion system) involves an etching process in which a phosphoric acid is used as a pre-treatment for the teeth, and the other (a self-etching dental adhesion system) involves a self-etching process for the teeth in which a tooth substance primer containing a polymerizable monomer having an acidic group is used and no water washing is required.
In order to make the resin-based filling/restoration further more convenient, there are proposed various related technologies in which the operative method of the dental adhesion system is further simplified. Patent Document 2 discloses a technology (an all-in-one, self-etching dental adhesion system) in which the tooth substance can be treated with a one-step operation using an adhesive in a single package without the need for a pre-treatment performed using a pre-treatment agent such as an etching agent, a conditioner, and a primer. Further, Patent Documents 3 to 5 propose technologies in which the cavity is filled with the resin-based filling/restoring material and the resin-based filling/restoring material is cured by one step of visible light irradiation in total with no substantial visible light irradiation performed after an adhesive is applied to the surface of the cavity. However, the resin-based filling/restoring material itself is not adhesive, and a dental adhesion system is required to bond the resin-based filling/restoring material to the cavity.
Meanwhile, dental treatments in which a glass ionomer cement that is adhesive to the tooth substance is used for filling/restoration or to seal pits and fissures are also widely performed. For the glass ionomer cement, basic glass which is a powder material is eroded by a liquid material which is an aqueous solution of an acid, and calcium ions and aluminum ions which are eluted during the erosion and carboxyl groups which are lateral groups of a polycarboxylic acid contained in the liquid material are subjected to chelate bonding and cured. Further, such ions are also subjected to chelate bonding with the tooth substance. Thus, the glass ionomer cement adheres to the tooth substance. The glass ionomer cement slightly stimulates the dental pulp, and thus can be said to be a highly biocompatible material. In addition, the material is self-adhesive to the tooth substance, and thus is widely used as a filling/restoring material (a glass ionomer-based filling/restoring material) as well as an adhesive material. The glass ionomer cement is advantageously characterized by persistently gradually releasing a minute amount of fluorine ions, and also used as a preventive material because it has a preventive effect, for example, suppressing or preventing a secondary caries and strengthening the tooth substance. In recent years, as described in Patent Document 6, there has been developed a material that has the respective characteristics of the resin-based filling/restoring material and the glass ionomer cement. Such material, however, still has the following defects: the material is low in physical properties and aesthetics compared to the resin-based filling/restoring material, and disadvantageously complicated in terms of the operative method because the material requires the concurrent use of the dental adhesion system and the pre-treatment agent.