Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Compositions to be polymerized by wave energy wherein said...
Reexamination Certificate
1999-05-04
2001-11-06
Seidleck, James J. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Compositions to be polymerized by wave energy wherein said...
C522S076000, C522S104000, C522S115000, C522S171000, C522S048000, C522S082000, C522S908000, C523S300000, C523S109000, C523S113000, C523S115000, C523S122000
Reexamination Certificate
active
06313189
ABSTRACT:
The invention relates to a process for the preparation of bioabsorbable polymerization products, characterized in that monomeric compounds essentially comprising compositions of the formula I
wherein
R
1
, R
2
and R
3
in each case independently of one another are —(CH
2
)—, —CH(CH
3
)—, —CH
2
—CH
2
—, —CH
2
—CH
2
—CH
2
—, —CH(CH
3
) —CH
2
—, —CH
2
—CH(CH
3
)—or 1,2-, 1,3- or 1,4-phenylene,
R
4
, R
4
′ and R
4
′ in each case independently of one another are H or CH
3
,
i, j and k in each case independently of one another are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 and
n is 0 or 1
are polymerized by means of electromagnetic radiation.
The invention also relates to a process characterized in that the compositions of the formula I are polymerized at temperatures between 0 and 80° C.
The invention also relates to a process characterized in that the polymerization of the compositions of the formula I is carried out with the addition of an initiator and/or an accelerator.
The invention also relates to a bioabsorbable polymerization product based on ethylene glycol- and/or glycero-oligoester-(meth) acrylates and obtainable by one of the processes mentioned.
Polymerizable binder systems based on (meth)acrylic acid esters on polyester oligomer chains from hydroxycarboxylic acids are known, for example, from EP 0 085 944 and EP 0 086 401.
Bone substitute materials and implantable drug depots based on acrylate polymers have been known for a long time. Polymer materials based on acrylic and/or methacrylic acid esters have proved suitable here on the basis of their biocompatibility, their outstanding strength properties, their favourable properties regarding the release of embedded pharmaceutical active compounds and, last but not least, on the basis of their processability appropriate for their use.
The invention was based on the object of providing bioabsorbable polymers which are easy to prepare, in particular those which can be used for the preparation of bone and tooth substitute materials.
The use of (meth)acrylic acid esters as monomers for use in dental materials is described, for example, in EP 0 206 074.
Prefabricated shaped articles (inserts) based on ethylenically polymerizable materials are disclosed, for example, in DE 43 39 399.
Other shaped articles having a predetermined pore structure and based on hydroxyapatite are described, for example, in DE 42 05 969.
A process for the preparation of dental fillings from photocuring plastic is described in DE 40 30 168.
Photopolymerizable compositions for dental treatment which are based on phenylene, diphenylene or bridged phenylene are disclosed in DE 21 26 419.
Other photopolymerizable compositions with additions of ketones are described in EP 0 090 493.
It has been found that the compositions of the formula I can be polymerized very readily by irradiation, and the polymer products thus obtained have very valuable properties in processing products such as dental lacquer, dental inlays or porous shaped articles, in addition to their bioabsorbability or biodegradability.
The bioabsorbable polymerization products based on ethylene glycol- and/or glycero-oligoester-(meth)acrylates according to claim
4
can be used in tooth and bone surgery.
The invention accordingly relates to a process for the preparation of bioabsorbable polymerization products, characterized in that monomeric compounds essentially comprising compositions of the formula I are polymerized by means of electromagnetic radiation. The radiation employed for the polymerization lies in the range from 800 nm (near infrared/visible light) up to to 10
4−4
nm (&ggr;-Rays or X-rays) . The range of visible and UV light in the range from 800 nm to 1 nm is particularly preferred, and the range from 800 to 50 nm is especially preferred here, while another preferred range comprises wavelengths from 1 to 10
−4
nm.
The ethylene glycol- or glycero-oligoester-(meth)acrylates are preferably formed from 1 mol of ethylene or glycerol, 2 to 10, in particular 2 to 6 mol of monohydroxy-monocarboxylic acid and 2 to 3, preferably 2 mol of methacrylic acid.
Preferred monohydroxy-monocarboxylic acids are glycolic acid, hydroxypropionic acid, hydroxybutyric acid and/or hydroxybenzoic acid, and lactic acid is especially preferred. Preferred compositions of the formula I are consequently the ethylene glycol- and/or glycero-oligolactide-bismethacrylates.
The polymerization is carried out at temperatures of 0 to 80° C., preferably between 10 and 60° C., especially preferably between 20 and 40° C.
Initiators can also be added. Possible suitable initiators are, for example, boron compounds, as described in EP 0 085 944.
The invention furthermore relates to a dental lacquer based on bioabsorbable polymerization products described herein obtainable
a) by mixing the monomeric composition with 0.05 to 4% by weight of camphorquinone,
b) applying the mixture to the tissue to be lacquered or the tooth and
c) polymerizing by means of electromagnetic radiation in the range from 50 to 800 nm.
Because of its chemical build-up, the dental lacquer according to the invention is absorbable. For this reason, it is particularly suitable for treatment of periodontitis, which is characterized by gingival pockets, the formation of colonized plaque, and finally with increasing loss of the periodontal ligament, which represents the connection between the root cement and alveolar socket. As a result of the loss of this tooth-holding apparatus, loosening and loss of the tooth finally occur. The current state of dental treatment comprises debridement of the intermediate space formed between the alveolar socket and tooth root, smoothing of the root surface and sewing-in of a film or membrane (for example Gore membrane) for the purpose of preventing connective tissue growing in from the gingiva in the context of controlled tissue regeneration.
The introduction of the film or membrane and fixing thereof make high demands on the operator. The dental lacquer according to the invention serves to anchor the film or membrane occlusively in the alveolar socket, or the lacquer is introduced into the defect in the context of a spacer for controlled tissue regeneration. To accelerate the regeneration of the tooth-holding apparatus, a rapidly absorbable material, such as, for example, bone sealant, can initially be introduced into the alveolar socket, and the dental lacquer can then be applied to this and polymerized. Calcium salts, antibiotics against bacterial colonization or disinfectants can be mixed into the dental lacquer to improve the formation of root cement by the odontoblasts. Another possibility is to mix in elastase inhibitors. In paradontal diseases, high elastase concentrations originating from polymorphonuclear granulocytes are found in the sulcus fluid. These high elastase concentrations are additionally responsible for the fact that the peridontal attachment apparatus is broken down and the attachment loss continues. Sodium monofluorophosphate, amine fluorides and/or other fluorine donors can furthermore be admixed.
For treatment of exposed necks of teeth, for example, dental lacquer comprising amine fluoride or local anaesthetics is currently applied in order to render the necks of the teeth less sensitive or to harden the necks of the teeth by the release of amine fluorides or other fluorides. However, these dental lacquers have only a short stability on the tooth surface, generally of just a few hours.
The dental lacquer is made to cure faster by mixing in camphorquinone. The amounts to be admixed are preferably between 0.05 and 4% by weight of camphorquinone, in particular between 0.1 and 0.5% by weight.
The polymerization is carried out, for example, by irradiation with visible or UV radiation at wavelengths of 800 to 50 nm, preferably between 500 and 300 nm.
Dental lacquers having different viscosities are obtainable by admixing, for example, glycero-oligoesters and/or glycero-oligoester-(meth)acrylates to ethylene glycol- and/or glycero-oligoester-(meth)acrylates to which camphorquinone has
Nies Berthold
Wenz Robert
McClendon Sanza L.
Merck Patent Gesellschaft mit beschrankter Haftung
Millen White Zelano & Branigan P.C.
Seidleck James J.
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