Dentistry – Apparatus – Having intra-oral dispensing means
Reexamination Certificate
1999-03-09
2001-02-06
Lucchosi, Nicholas D. (Department: 3732)
Dentistry
Apparatus
Having intra-oral dispensing means
C433S224000
Reexamination Certificate
active
06183253
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to an insert for filling the dental canal comprising means for anatomically and physiologically filling up the root canal.
STATE OF THE TECHNIQUE
In dentistry, and in particular in endodonty, the root canals must be hermetically obturated. In the prior art, certain specific materials are generally used, such as gutta-percha, or zinc/eugenol oxide pastes, or for example Bakelite resins in the form of bi-component preparations, which are inserted in the canal by mechanical means.
These known materials have to be partially removed when the coronal part of the tooth has to be reconstituted. A pivot is generally inserted and sealed in the root canal after shaping to act as anchoring part for a coronal reconstitution. The coronal reconstitution phase is carried out in a different session from that of the canal obturation.
According to the document CH-A-562,605, the pivots can be made of metallic material and are each provided with a thread designed for screwing the base of the pivot into the root canal.
Pivots made of pre-fabricated composite material, which may be reinforced by fibres, are described in the documents U.S. Pat. No. 4,936,776, DE-A-3,825,601 and EP-A-0,432,001. Each pivot presents a straight finished shape and a rigid structure before insertion in the canal. Should a root be curved, the pivot can therefore in no case follow this curving, and the practician then has to enlarge the canal to enable the pivot to be fitted. The work of enlarging the canal is liable to reduce the solidity of the root, with non-negligible risks of perforation.
In all these known techniques, the anchoring pivot is generally made of a different material from that of the canal filling, and the joining interface between the pivot and the canal filling material forms a fragilised zone subjected to large mechanical stresses in the course of chewing.
OBJECT OF THE INVENTION
A first object of the invention is to achieve a canal filling insert of high mechanical strength, and able to be easily inserted in the root canal.
A second object of the invention relates to a process enabling canal filling and construction of an anatomical and physiological root anchoring to be carried out in a single operation.
The endodontic insert according to the invention is characterized in that the filling means comprise a ductile or malleable core made of a composite material in polymerised state, sheathed in one or more sleeves made of a composite material pre-impregnated with resin, and being in a first pasty state prior to polymerisation so as to make the insert material ductile and malleable before and during introduction of the insert into the root canal, said material then being able to be polymerised as required by cross-linking means to change to a second polymerised state after the insert has been inserted in said canal.
According to a preferred embodiment, the core of composite material comprises an organic matrix reinforced by fibres and/or organic or mineral particles, or both. The organisation of the core reinforcing fibres may be unidirectional, pluridirectional, or random.
According to one feature of the invention, the core is hollow and comprises an internal duct for injection of a glue-based sealing agent into the canal. The wall of the core is advantageously porous to allow passage of the glue, introduced under controlled pressure via the duct.
According to another feature of the invention, the paste constituting the sleeve or sleeves comprises an organic matrix reinforced by fibres or organic or mineral particles, of the same nature and structure as those of the core.
The external sleeve is formed by a sheath made of composite material of the same type as the internal sleeve or sleeves, said sheath being malleable and acting as container for all the materials of the core and of the sleeves.
The structure of the fibres of the external sheath is arranged to allow the excess resin to pass by extrusion as insertion of the insert in the canal takes place. The excess resin mixes with the sealing agent glue to seal the small dentinary canals of the root.
The upper part of the insert which emerges from the root canal can advantageously act as prop or pivot for a coronal reconstitution. The same material is thus used for filling the root canal and for reinforcing the residual structures of the tooth. The canal obturator and the anchoring pivot are made of one and the same material.
The insert is presented in the form of a manufactured product stored away from electromagnetic radiation in a sealed sachet at a temperature of less than 37° C.
After the insert has been fitted in the canal, polymerisation by the action of the cross-linking means can be performed, by electromagnetic radiation, and/or light rays, and/or by thermal effect. Mass polymerisation of the insert and of the sealing agent glue is performed at the same time which enhances the mechanical strength of the assembly.
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patent: 4936776 (1990-06-01), Kwiatkowski
patent: 4952150 (1990-08-01), Schiwiora et al.
patent: 5074792 (1991-12-01), Bernadat
patent: 5797748 (1998-08-01), Reynaud et al.
patent: 5816816 (1998-10-01), Scharf
patent: 5890904 (1999-04-01), Reynaud et al.
patent: 5915970 (1999-06-01), Sicurelli, Jr. et al.
patent: 562 605 (1975-06-01), None
patent: 38 25 601 A1 (1989-03-01), None
patent: 0 432 001 A1 (1991-06-01), None
patent: WO 96/15731 (1996-05-01), None
Billet Gilles
Clunet-Coste Bruno
Collombin Andre
Maneuf Bernard
Nordvall Leif Siguard
Lucchosi Nicholas D.
Ollif & Berridge, PLC
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