Dentistry – Apparatus – Having intra-oral dispensing means
Reexamination Certificate
2000-10-11
2001-10-23
Lewis, Ralph A. (Department: 3732)
Dentistry
Apparatus
Having intra-oral dispensing means
C433S088000
Reexamination Certificate
active
06305934
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to an apparatus for use in repairing teeth. In particular, the invention relates to a hand-held multifunction syringe for repairing teeth having multiple reservoirs for containing viscous material (e.g., resin and etchant), conduits for delivering etchant, water, air, and resin to an affected area, wherein the syringe is capable of delivering etchant, water, air, and resin to the affected area, and further characterized by a light emitting source capable of curing the resin extruded onto the affected area.
BACKGROUND OF THE INVENTION
The principles of adhesion, wherein the molecules of one substance bind or are attracted to molecules of another substance necessarily play a significant role in dentistry. For example, the adhesion process directly affects the dental restoration of teeth. In brief, adhesion is a surface attachment process wherein the attachment of one substance (e.g., resin or resin composite material) to another (e.g., enamel or dentin on a tooth structure) can be accomplished by mechanical bonding. As applied to dentistry, mechanical bonding involves the penetration of an adhesive or resin into crevices on the surface of the tooth structure.
Current examples of mechanical bonding used in dentistry includes the use of resin restorative materials. Nevertheless, these resins are not capable of truly adhering to a tooth structure. In a method known to those skilled in the art, a fluid or semi-viscous resin is used to create a mechanical bond between the resin and the tooth structure because the flowing resin readily penetrates into the surface defects (i.e., crevices) of the tooth structure. Subsequently, once the fluid resin hardens, the plurality of resin projections embedded in the tooth surface provides a base for mechanical attachment. The procedure for using a fluid or semi-viscous liquid (e.g., resin or adhesive) is referred to as wetting. If the fluid does not wet the entire surface of the affected area of the tooth, adhesion between, for example, resin and the tooth structure will be negligible or non-existent. Poor adhesion or non-adhesion between the tooth structure and a restorative material often results in leakage adjacent to the restored area. This leakage typically leads to staining, secondary tooth decay, and irritation to the pulp of the tooth structure. As discussed below, a number of factors such as the cleanliness of the surface influence the ability of an adhesive or resin to wet the surface of the tooth surface.
A popular technique for applying resin restorative materials includes treating the enamel of the tooth structure with phosphoric acid prior to applying the resin. This technique is commonly referred to as the acid-etching technique. The acid creates microscopic pores in the enamel surface of the tooth structure into which the resin subsequently flows when delivered into the etched area. As referenced above, the resin projections jutting into the pores in the enamel surface of the tooth enhance the mechanical retention of the restoration upon hardening, thereby reducing the possibility of interfacial marginal leakage.
The most significant problem associated with bonding resins to the tooth structure during restorative procedures is contamination by water or a patient's saliva. During routine dental restorative procedures, a dentist must constantly attempt to keep the affected area of a tooth dry. Although tools such as dental dams, air jets, and suction devices are used to prevent saliva from encroaching upon the affected area, some saliva inevitably reaches portions of the affected area during the restorative procedure. This situation is especially true during dental restorations whereby the dentist must restore the tooth in a stepwise fashion involving multiple dental instruments. During a routine repair of a decayed area on the tooth surface, the dentist must first retrieve an acid application tool (e.g., syringe) from a storage rack, etch the decayed area for approximately fifteen seconds, and then replace the acid applicator on the storage rack. Upon etching the tooth, the dentist retrieves an air and water syringe from the storage rack, and rinses the acid etchant off the enamel with a stream of water for approximately ten to twenty seconds. Next, the dentist applies air to the affected area in order to dry the same while attempting to exclude all moisture. Upon returning the air and water syringe to the rack, the dentist must quickly retrieve a resin applicator from the storage rack and apply resins to the prepared area before the patient's saliva reaches the prepared area. The etched surface must be kept clean and dry until the dentist applies the resin in order to form a sufficient bond. Upon returning the resin applicator to the storage rack, the dentist retrieves a light source and exposes the affected area in order to cure the resin. Inevitably, some moisture will reach the affected area during the lengthy process described above as a result of the patient moving his tongue over the affected area, attempting to swallow, or partially closing the mouth.
Adding to the difficulty of keeping the prepared area dry is the fact that the inorganic bonds of the tooth structure have a strong affinity for water. As result, the presence of at least a small layer of water on the surface of the prepared cavity must be accepted. This water layer reduces the surface energy and thus may reduce the wetting of the restorative material.
As referenced above, the most effective procedure for enhancing mechanical bonding commonly used by dentists is the acid-etch technique. The acid-etch technique has promoted the use of resin-based restorative materials because it provides a strong mechanical bond between resin and enamel/dentin (e.g., resin bonded metal retainers, porcelain inlaid veneers, and orthodontic braces). Accordingly, dentists typically use thermoplastic resins to restore and replace missing teeth. Most resin systems used in dentistry are based on methacrylates, and methyl methacrylate in particular.
Specifically, the process for bonding enamel and resin-based restorative materials involves the etching of the enamel to promote selective disintegration of the tooth enamel resulting in a microporous surface. Etched enamel (as opposed to normal enamel) is characterized by a high surface energy, and allows a resin to readily wet the surface and penetrate into the microporosity. Upon penetrating the microporosity of the etched enamel the resin can be polymerized to form a mechanical bond to the enamel. Polymerization occurs through a series of chemical reactions by which a macromolecule (i.e., polymer) is formed from large numbers of molecules known as monomers. Polymerization can occur either by series of localized reactions, commonly referred to as step growth polymerization, or by simple addition reactions, commonly referred to as addition polymerization. Most dental resins are polymerized by addition polymerization.
The resin projections (commonly referred to as “tags”) may penetrate ten to twenty microns (&mgr;) into the pores of the enamel, but their links are dependent on the enamel etching time. The standard acid used to produce the porous enamel is phosphoric acid at concentrations between thirty to fifty percent. Typically, dentists prefer an etchant in a gel form because the gel provides control over the exact placement of the etchant on the affected area. The application time of the etchant may vary depending on the degree of decay of the tooth. For example, a tooth having a high fluoride content resulting from fluoride treatment (i.e., treated water supply) may require a longer etching time as compared to a non-treated tooth. A common procedure includes applying the etchant for fifteen seconds.
Accordingly, upon etching the tooth, the dentist rinses the acid etchant off the enamel with a stream of water for approximately twenty seconds, then directs a jet of air across the affected area until the enamel and dentin is sufficiently dry. As discussed above, in order to form a
Lewis Ralph A.
Summa & Allan P.A.
LandOfFree
Multifunction syringe for repairing teeth does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Multifunction syringe for repairing teeth, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multifunction syringe for repairing teeth will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2575012