Saliva cured one component dental formulations

Details Saliva cured one component dental formulations Saliva cured one component dental formulations

1999-09-29

2001-09-04

Koslow, C. Melissa (Department: 1755)

Compositions: coating or plastic

Coating or plastic compositions

Dental

C433S228100, C523S116000

Reexamination Certificate

active

06284030

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates to a novel dental temporary filling material/cement comprising an inert viscous hydrophobic matrix in which fine solid particles are dispersed such that, upon reaction with water and/or certain organic polyacids, the physical form of such blend is transformed from that of a moldable paste to a solid. The high concentration of hydrophilic solid particles ensures water conductivity through the mass of the material. Such moisture penetration is critical to achieve a satisfactory depth of cure, as measured as a distance from the saliva/restoration borders.
In this invention, the role of the dispersed solid particles is, therefore, of dual nature:
As components responsible for the cure of the cement and its final mechanical properties, and
As moisture conductors through the mass of the restoration.
The curing of the materials of this invention occurs as a result of two types of chemical processes occurring simultaneously:
Reaction of salts and/or oxides with water or formation, of adducts of salts and waters, and
Reaction of alkaline glass sites with polyacids, or the reaction of such polyacids with metal oxides, hydroxides, or salts of such materials, with weak organic acids.
The chemical composition of the formulations of this invention resulted in cements featuring highly desirable characteristics. These materials were found particularly suitable for use as temporary restoratives and cements where the ease and speed of application, fast cure, resistance to the oral environment, biological mildness, and ease of removal are of primary concern. Astonishingly, it was further realized that the formulations of this invention, contrary to those of the prior art, show no or minimal volumetric expansion during cure—a feature of critical importance for dental restoratives and cements. An additional advantage is that sustained fluoride release can easily be implemented without negatively affecting the characteristics or the integrity of the restorative.
DESCRIPTION OF PRIOR ART
Known dental restoratives an cements may be separated by their method of cure into three groups:
Self cured materials, usually representing a two part system in which the curing process is initiated by mixing the two components;
Light cured materials, usually a one part system in which the curing process is initiated by irradiation with high intensity light; and
Saliva cured materials, in which curing occurs as a result of hydration of inorganic components of the formulations.
While the first two types are primarily used for permanent dental restorations, the third is limited to temporary applications where short service time, typically of less than seven days, is reasonably expected.
Important features of materials for temporary applications, as dictated by both clinical and economical considerations include easy and fast application, short curing time, low cost, long shelf life, adequate depth of cure, biocompatibility, resistance to oral fluids, adequate mechanical strength, ease of removal, and compatibility with permanent restoratives and cements.
Prior art saliva cured-type temporary restoratives/cements were generally inadequate in many respects. The curing time was slow, making the material vulnerable to premature deterioration, especially during the hours immediately after application. The curing of the material progressed very slowly, and was frequently limited to a layer within a few millimeters of the material/saliva borders. Poor resistance to mastication forces, wear, and oral fluids resulted in excessive premature deterioration of the restorations or structural failures.
The present invention addresses the shortcomings of such prior art materials. The addition of a secondary curing mechanism of polyacid salt formation to the hydrate formation mechanism of the prior art allows for faster curing and greatly increased strength. The presence in this invention of initially hydrophilic but reactive components such as anhydrous polyacids facilitates penetration of moisture through them mass of uncured material, thus enhancing the depth and speed of cure.
The material of this invention features greatly increased depth of cure, improved resistance to oral fluids, and superior mechanical strength. These desirable characteristics were achieved while meeting other pertinent requirements, including biocompatibility, ease of application, long shelf life, ease of removal and compatibility of residues with all known dental restoratives and cements.
DETAILED DESCRIPTION OF THE INVENTION
The dental formulation embodying the present invention which cures upon contact with saliva includes a hydrophobic matrix component, an inorganic particles component and an anhydrous acid component.
The preferred hydrophobic organic matrix for the dental cement formulations of this invention comprise an organic material of viscous liquid or semi-solid consistency such as fatty acids or their esters, polyalkalenes, mineral oils, paraffins, synthetic or natural waxes, and silicone oils. Polyalkalenes and paraffins were found to be the most suitable matrices.
The reactive inorganic solid particles which contribute, in part, to the hardening of the cement formulation may include calcium sulfate, calcium sulfate hemihydrate, calcium silicate, calcium oxide, magnesium oxide, magnesium chloride, phosphate salts, colloidal silicic acid and certain organosilicone components such as alkoxysilicones. Solid inorganic particles which further contribute to the hardening of the cement, and the substantial improvement in characteristics of the cured material, include, in addition to those mentioned above which contribute to hardening by reaction with water, alkaline glasses, zinc oxide, calcium silicate, calcium hydroxide, and magnesium silicate. Alkaline glasses and zinc oxide are the most preferred of such additional additives.
The inorganic particles which contribute to the hardening of cement, namely calcium sulfate (CaSO
4
) or calcium sulfate hemihydrate (CaSO
4
.½H
2
O) are present in concentrations of from about 10 to 55% by weight of the formulation.
The inorganic particles component may also include from 2 to about 15% by weight of the formulation calcium phosphate salts such as CaHPO
4
, Ca
8
H
2
(PO
4
)
6
, Ca
3
(PO
4
)
2
and/or hydrates thereof.
Additionally inorganic particles reactive with organic particles such as zinc oxide, calcium oxide, calcium hydroxide, magnesium oxide, barium oxide, strontium oxide, calcium carbonate, calcium silicate, magnesium silicate and/or zinc carbonate are suitable for the invention.
The anhydrous acid, polyacid or acid anhydride is preferably a polyacrylic acid, and has on average molecular weight ranging from 2,000-250,000.
The formulation may also include, if desired, additives which affect the appearance of the material. The additives are preferably dyes or pigments which are used to enhance the aesthetics and to facilitate distinction of the cement from tooth structure. Preferred dyes or pigments are iron oxides or titanium dioxide.
It is also envisioned to add, if desired, fluoride releasing salts to the formulation. Salts such as sodium fluoride, stannous fluoride, potassium fluorosilicate, sodium fluorosilicate, zinc hexafluorosilicate or sodium monofluoro phosphate are preferred.
The organic acid is selected from polyacrylic, itaconic, tartaric, citric, maleic, oxalic or lactic acids or their copolymers. Such acids are present in anhydrous form in the formulations of this invention, preferably at concentrations of 1-20% of by weight in the cement. Their reaction with alkaline particles is triggered by the presence of water.


REFERENCES:
patent: 3837865 (1974-09-01), Pellico
patent: 4518430 (1985-05-01), Brown et al.
patent: 4612053 (1986-09-01), Brown et al.
patent: 5051130 (1991-09-01), Futami et al.
patent: 5108506 (1992-04-01), Yuhda et al.
patent: 5154613 (1992-10-01), Cohen
patent: 5569308 (1996-10-01), Sottosanti
patent: 6028125 (2000-02-01), Combe et al.

Affiliated with

Also associated with

Rating

Saliva cured one component dental formulations does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Saliva cured one component dental formulations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Saliva cured one component dental formulations will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2504651