Tapered light probe with non-circular output for a dental light curing unit

[0002] 1. Field of the Invention

[0003] The invention relates generally to dental tools and, more particularly, the invention relates to tools using light to cure dental materials containing resins.

[0004] 2. Description of Related Technology

[0005] Dental restoration procedures often require various resin containing materials such as composites and adhesives to be filled into a tooth cavity or area being repaired, and subsequently cured. With certain restoration procedures, the filling and curing cycle may be repeated several times. The curing process is often performed using a curing tool, which emits light from a source, such as a bulb, and through a bundle of optic fibers, to thus result in a focused light output. The light output is directed at the resin and the resin is quickly cured by polymerization.

[0006] To facilitate the curing process, the fiber optic bundle may be provided within a probe or light guide extending from the curing tool or gun. The probe may extend linearly from the gun with an angular cant toward a distal end to enable the operator to more easily access the tooth being repaired.

[0007] Prior art light probes are typically 8-13 mm in diameter, and utilize a round tip at the distal end. Light from the dental curing gun is communicated through the light probe along the optic fiber bundle and exits the distal end in a circular pattern which is applied to a dental resin for curing. In order to quicken the curing process, some light probes have used a smaller cross-sectional area at the distal end being drawn from a larger cross-sectional area at a proximal end. In this manner, the light from the curing gun is amplified by being drawn into a smaller cross-sectional area and focused on the area being cured, resulting in faster curing cycles.

[0008] However, some areas which require curing are significantly smaller than others or are uniquely shaped. For example, when curing a plane of adhesive between the surface of a tooth and an orthodontic bracket, the area of exposure can be considerably smaller than that of typical tooth restoration, such as cavity fillings. In such cases, light being delivered from a round tip is not always efficiently projected across the interface, resulting in application over areas that do not need to be cured. This does not optimize the useful intensity of the light, thus resulting in an inefficient light probe.

[0009] According to the invention, a light probe for use with a dental curing gun includes a first end and a second end, the second end having a non-circular cross-section. The light probe further includes a straight section between the first and second ends, with an optically transparent medium extending through the straight section from the first end to the second end.

[0010] Other aspects and features of the invention may become more apparent from the following detailed description when taken in conjunction with the accompanying drawings and the appended claims.

[0011] FIG. 1 is an elevational side view of a dental curing gun employing a light probe constructed in accordance with the invention.

[0012] FIG. 2 is a perspective view of the light probe of FIG. 1 unattached from the curing gun.

[0013] FIG. 3 is an elevational side view of the light probe of FIGS. 1 and 2 with a partial cutaway revealing the fiber optic bundle.

[0014] FIG. 4 is a cross-sectional view of the fiber bundle of FIG. 3 taken at line 4—4.

[0015] FIG. 5 is a cross-sectional view of the fiber bundle of FIG. 3 taken at line 5—5.

[0016] FIG. 6 is a view of the light probe of the invention being used in conjunction with a curing gun to secure an orthodontic bracket to a tooth.

[0017] Referring now to the drawings, and with specific reference to FIG. 1, a dental curing gun according to the invention is generally depicted by reference numeral 20. As shown therein, the curing gun 20 may include a barrel 22 and a grip 24. The barrel 22 may house a light source, such as a bulb 26 (a tungsten halogen lamp, for example) adapted to emit light when an electrical circuit thereto is closed by a trigger 28. The curing gun 20 is connected to a power source (not shown), which is typically AC power, although battery power is possible. The elements of the gun 20 may vary from tool to tool, and simply serve as background environment for the invention.

[0018] When the trigger 28 is actuated, light (designated 30) is emitted by the bulb 26 and directed through the probe 32. The probe 32 typically includes a plurality of fiber optic fibers 34 wrapped in a protective sheath or conduit 36 as shown in FIGS. 4 and 5. Alternatively, a solid, optically transparent material, such as glass or plastic, may be utilized in lieu of individual fibers. The conduit 36 maybe manufactured from any suitable material, including fused glass. As shown, the conduit 36 may include a connection end 38 and a discharge end 40. The connection end 38 is typically provided with an attachment mechanism 42 to allow the probe 32 to be readily attached and detached from the gun 20, for purposes such as replacement or sterilization. A straight section 44 extends from the connection end 38 and merges into a canted section 46 proximate the discharge end 40. A nexus 48 (illustratively bent) defines the merger between the straight section 44 and the canted section 46. A protective rim 50 may be provided at the discharge end 40 to protect the end faces of the optic fibers 34. The rim 50 may be adhered to the probe 32 with a suitable adhesive, such as an epoxy adhesive.

[0019] As seen best in FIG. 2, the conduit 36 tapers along its length from a relatively large, preferably circular, input area at its connection end 38 to a relatively thin non-circular ribbon at the discharge end 40. The overall size and area of the output may vary, but may be provided at, for example, a ratio of 3:1 (input area to output area), with a overall probe length of 15 mm. Such a probe increases light intensity, defined as light flux per unit area, by a factor of three. Preferably, the size of the output is comparable in size to the dental area being worked. For example, a thin ribbon-type output may be the most efficient way of applying light to adhesive at a tooth/bracket interface, but other output shapes including, but not limited to, triangles, tetragons, polygons, and the like are possible.

[0020] Since a fixed number of optic fibers 34 are positioned within the conduit 36, each optic fiber 34 is specifically oriented within the conduit and aggregately reduced in diameter along a longitudinal axis of the conduit 36 in order to output light in an intensified, non-circular or substantially linear pattern. As can be seen in FIGS. 3-5, the fibers 34 are arranged at the connection end 38 in a cylindrical bundle 52 having a substantially round cross-sectional input area. As the fibers 34 traverse the length of the conduit 36, the fiber optics form an aggregate bundle 54 having a non-circular or substantially linear cross-sectional output. Thus, at the discharge end 40, the cross-section will be non-circular or substantially linear. The optic fibers 34 are reduced in diameter by tapering along their length, in correspondence with the tapering of the conduit 36. The fibers 34 may be tapered by heating and stretching techniques, so that each fiber 34 has a larger diameter at the connection end 38 than at the discharge end 40. The fiber bundle thus has a larger cross-sectional area at the connection end 38 (see FIG. 4), and a significantly smaller cross-sectional area at the discharge end 40 (see FIG. 5).

[0021] Referring to FIGS. 1 and 2, light 30 from the curing gun 20 is coupled into the fiber optic bundle input at the connection end 38. As the light 30 is communicated along the conduit 36, the light intensity is significantly amplified as the cross-sectional area of the fiber bundle gets smaller, because the light 30 is being drawn into a smaller area. Upon output at the discharge end 40, the light 30 is arranged in a non-circular or substantially linear pattern.

[0022] As shown in FIG. 6, when the light pattern is applied to the area of exposure of an adhesive 56, the light 30 is efficiently arranged along a line projected across a plane of the adhesive 56 between a surface of a tooth 58 and an orthodontic bracket 60. The light 30 is only applied where it is needed, thereby optimizing the useful intensity of the light 30.

[0023] Preferably, the edge of the discharge end 40 is placed along the edge of the tooth 58. The light 30 exits parallel to the surface of the tooth 58 so as to project the light 30 across the plane of the adhesive 56.

[0024] The intensity of the light 30 in the smaller, non-circular or linear area of the discharge end 40 is comparable to that of a plasma arc lamp or laser, resulting in quick and efficient curing cycles. The light probe 32, as described above, combined with a curing gun 20 provides light intensity and curing speeds for orthodontic bracket attachment that are comparable to plasma arc lamps or lasers, but at substantially less cost.

[0025] While the present invention has been described with reference to specific examples, which are intended to be illustrative only, and not to be limiting of the invention, it will be apparent to those of ordinary skill in the art that changes, additions or deletions may be made to the disclosed embodiments without departing from the spirit and scope of the invention.