GB2129307A - Placement devices for dental splints or retainers - Google Patents

Abstract

A novel placement device used for temporarily holding flexible splinting material against tooth surfaces while bonding same to the teeth during a dental splinting procedure, and novel methods for carrying out the splinting procedure using monofilaments for drawing the splinting material into the interproximal spaces. The monofilaments are also useful for bonding bridges or retainers to teeth. The splinting material can also be bonded over the tooth's biting surface. <IMAGE>

Description

SPECIFICATION Dental placement devices and methods This invention relates to improved devices for the placement of dental splints or retainers on a patient's teeth, and novel methods for dental splinting and application of bridge retainers and is useful not only for humans but also for animals.

Recently different types of dental splinting devices and materials have become popular for stabilising mobile or avulsed teeth. Some of these splinting materials include metal and plastic meshes, perforated metals, metal rods, bars and the like. Our published U.K. patent application GB 210093A describes some of these new splinting materials and the methods of applying them, the contents of which are hereby incorporated by reference.

Problems have been experienced by dental practitioners in trying to adapt, place, handle and bond these splinting materials to tooth structure.

An even greater problem arises when severe crowding of teeth exists making it difficult or impossible to place materials effectively and efficiently and excessive time is consumed in such situations as well as added discomfort for the patient and frustration to the dentist or his assistants.

A known placement device has been described, which is made of plastic provided with tabs and in which a slot is cut so that the placement material could be placed into the slot after the application of the plastic to the teeth. This device is extremely complex in terms of fabrication of the plastic and requires careful slotting of thin plastic which is costly to manufacture. Furthermore, this prior art device requires careful placement into the slot of a strip of metal mesh which when pushed through often catches and the very fine mesh wires bend preventing the metal from being pushed into the slot. This often causes irreparable damage to the strip of metal, and great time loss to the dentist and patient. A further disadvantage of this prior art device is that the metal strip once placed through the plastic holder must be applied on to the segment of tooth to be splinted.To accomplish this, the plastic tabs must be slid along the metal strip. This often causes the metal mesh wires to catch again causing bending of the wires. Once the plastic holder is properly placed and resin bonded to the teeth, it is necessary to leave the plastic tabs in place. This is a significant disadvantage. It is impossible to remove the tabs without disturbing the embedded metal and resin.

In another dental procedure, known as acidetch bridge work or resin bonded retainer a replacement toothed mounted on a retainer with bracket ears is placed by the dentist in the location where a tooth of the patient is missing, and the dentist holds the bracket ears against adjacent teeth while the bracket ears are bonded thereto. A problem is the difficulty of holding the small replacement tooth by hand or instruments while evenly applying pressure of the brackets against the tooth structure during hardening of the bonding material. Moreover, there is always concern about accidental droppina3 of the retainer and aspiration by the patient.

It is accordingly an object of the present invention to provide a novel placement device for simple placement of splinting materials to stabilise mobile teeth.

Another object of this invention is to provide novel method of aligning splinting materials to the teeth.

Still another object is to provide a method of removing the placement device after the bonding material has hardened.

A further object is improved devices and methods for facilitating the placement and bonding of splinting materials, bridges, retainers and similar prosthetic devices.

Still a further object is improved procedures to stabilise teeth individually as well as collectively.

Briefly stated, in accordance with one aspect of the invention, monofilament strips or its equivalent are used as the placement device. The strips are guided by the practitioner into the interproximal spaces of the segment of teeth to be immobilised, and are rested at the gingival portion.

The splint is now placed on the lingual or buccal segments. The monofilaments are now brought over the splint and placed interproximally into the upper spaces, the ends are brought together and can be pulled or drawn as a draw string to tighten and bring or press the splint against the lingual or buccal segments to hold temporarily the splint against the teeth and to allow the splint to be brought into the interproximal section for additional bonding strength when the bonding material is applied as described in said U.K.

application.

A further advantage of this aspect of the invention is that, because the monofilaments are placed interproximally, the splint is automatically customised to the patient's tooth position and condition. Also, once the bonding material hardens with a splint covered or impregnated with the resin, the special monofilaments will not adhere and will simply slip away from the hardened resin by releasing one end of the looped filaments and pulling.

In accordance with another aspect of the invention, a placement device is provided comprising plural monofilaments tied together at least at one end by a common strip. With this structure, after each of the free ends of the monofilaments have been inserted interproximally and the splint applied, the common strip can be manipulated as a unit for drawing the plural filaments to press the splint against the teeth.

In accordance with still a further aspect of the invention, especially in a situation where a posterior tooth is missing, the monofilaments can be used to tie portions of the splint to the teeth present to secure same thereto prior to application of the bonding material, and can also be used interproximally to tie together splinting material provided on both facial and lingual surfaces of the teeth to be stabilised. This method increases the teeth surface area covered and thus the holding power of the splint to the teeth, greatly simplifying application of the bonding material and enhancing its bonding strength after hardening.

In accordance with another aspect of the invention, which is applicable not only to splinting materials but also to bridges or retainers, the monofilament placement means are attached, as by tacking or threading to the splint, bridge or retainer, so that the placement means can be used to support and position the latter in addition to pressing or pulling same against the patient's teeth after properly positioned during the bonding process. This further simplifies the involved dental procedure and reduces the possibility of accidentally dropping the prosthetic or stabilising device.

In accordance with still another aspect of the invention, the splinting materials bonded over the incisal or biting surface of the tooth or teeth, and if necessary or desired subsequently adjusted to improve the shape of the biting surfaces. This offers the benefit of a relatively low cost procedure for reinforcing weak incisal tooth edges, especially for brittle anterior teeth, without significantly compromising the patient's appearance.

The invention will now be described in greater detail in connection with several exemplary embodiments, reference being made to the accompanying drawings wherein: Figure 1 is a schematic view of several teeth showing a first step in accordance with a method of the invention; Figure 2 is a view similar to Figure 1 of a further step of the method; Figure 3 is a view similar to Figure 1 showing the splint in position after bonding at the conclusion of the procedure; Figure 4 is a schematic plan view of one form of placement device in accordance with the invention; Figure 5 is a schematic view of posterior teeth illustrating an early step in a method in accordance with another aspect of the invention; Figure 6 is a view similar to Figure 5 of a later step in that method;; Figure 7 illustrates a splinting procedure using monofilaments tacked to the splinting material in accordance with another aspect of the invention; Figure 8 illustrates a later step in the procedure of Figure 7; Figure 9 shows a modification for the procedure of Figure 7 employing monofilaments pre-threaded through a mesh-type splinting material; Figure 10 shows a further modification employing monofilaments pre-threaded through a perforated band-type splint; Figures 11 and 12 show modified procedures using tacked and pre-threaded monofilaments, respectively, for placement of a bridge or retainer; and Figure 13 shows part of a procedure in accordance with another aspect of the invention herein the splinting material is bonded over the incisal edge of a tooth.

The invention is for use with many kinds of splinting materials which are of strip or rod configuration with or without perforations. The strip or thin rod should have sufficient flexibility that application of the placement device will cause the strip or rod to bend or flex and be pulled tight up against the tooth surfaces and into interproximal spaces. We prefer to use thin flexible perforated strips of metal or plastic as described in said U.K. patent application.

The bonding materials that can be employed in the invention can be chosen from amongst those currently available to dental practitioners for many uses in restorative dentistry. These are typically resin composites which are supplied by commercial dental suppliers in the form of pastes or creams, or in the form of powders when mixed with resin liquids form liquids, pastes or creams, which can be spread by the dentist over the splint and will self-harden usually by polymerisation. Our said application has several examples of hardenable resins and composites suitable for use in the present invention.

Though the monofilament can be constituted of a thin malleable wire, the monofilament preferably is constituted of a plastic resin such as nylon.

Being non-stranded and non-mesh avoids the problems of strand or mesh ends catching on the tooth or splint during interproximal insertion.

Another advantage of a nylon monofilament is that it will not adhere to the hardened bonding material and thus can be removed after use.

However, metal monofilaments, or filaments of another composition can be substituted if desired.

If the filament material does bond to the hardened bonding material, it can be left in place after snipping of the unbonded parts. Alternatively a non-stick layer, such as Vaseline, can be applied to the filament to prevent adhesion.

Referring now to the drawings, Figure 1 shows schematically a lingual view of a teeth segment to be splinted comprising four teeth of which, say, the two end teeth 10, 11 are immobile but the adjacent middle teeth 12, 13 are mobile and are to be stabilised by the application of a splint. As depicted in Figure 1, three monofilaments 1 5 are inserted in the interproximal spaces 14 and rested on the gingival tissues. Next, as depicted in Figure 2, a flexible splinting mesh 17 is manually placed on the lingual surfaces across the teeth segment to be stabilised. Each of the filaments 1 5 are next reinserted interproximally, as shown at 1 5', so as to loop over the mesh 17. The dentist or his assistant next collects the free ends of the filaments, designated 18, which protrude from the facial surfaces and pulls them taut, as plural draw strings can be drawn taut. This action temporarily presses the splinting mesh 1 7 against the teeth surfaces 14 as depicted in Figure 2. Next, while still holding the filaments taut composite bonding material (not shown) is spread over the mesh surface so as to fill the mesh interstices and to extend a thin layer over the mesh edges and into the interproximal spaces 14 through the mesh interstices and around the mesh edges. This is described in our U.K. application and is not shown to avoid cluttering up the drawing. Then the composite is allowed to harden while still holding the filaments taut. Typically, this takes about five minutes.After hardening, if the filaments 1 5 have not adhered to the hardened composite, one end of each is released and the held end used to pull the filaments 1 5 out of the interproximal spaces 14. The final structure is the composite-stiffened mesh resin-bonded to and across the teeth and acting as a splint anchored on the immobile teeth 10, 11 to stabilise the mobile teeth 12, 13. This is illustrated in Figure 3, with again the resin omitted for clarity. This completes the procedure, except for any trimming of excess portions of the splint or hardened composite as deemed necessary.

As will be evident from the preceding description, the method of the invention is simple to practise, consumes little time, and is less subject to the annoyances and frustrations of the known procedures. Increased bonding strength can be achieved, since the splinting mesh contacts more tooth surface and is reinforced by the splint portions, shown schematically at 1 8 in Figure 3, extending into and bonded into the interproximal spaces 14. Moreover, the placement device, in this case the monofilaments, used to temporarily hold the splint against the teeth during bonding is inexpensive and readily available, and can be disposed after use.

Figure 4 illustrates one form of novel placement device wherein plural filaments are united by a common strip portion to simplify manipulation of the placement device during the splinting procedure. As shown, the device, indicated generally by 21, comprises six monofilaments 22 joined or united at one front end by a first common strip 23, preferably, but not necessarily, of the same material as the monofilaments 22, and also united at the opposite ends by a second common strip 24. In the form illustrated, which is exemplary only, the strips 23, 24 are of thin plastic sheet material provided with holes 25, and the filaments 22 are each passed through the holes 25 as shown and knots 26 formed at their free ends to prevent the filaments from slipping back out of the holes. Alternatively, the filament ends could be bonded or otherwise secured to the strips.While only one common strip 23 or 24 can be used, we prefer to use common strips at both ends to simplify handling. While it is also possible for all filament ends at one side to come to a common point or juncture, we prefer that the ends of the monofilaments, which are typically 0.1-1.0 mm wide, where joined, are spaced apart by a distance, indicated at 27, approximating the interproximal spacing of, for example, 3-8 mm.

In use, the monofilaments are inserted, one at a time, interproximally, in the same manner as dental floss while the dentist holds the filaments taut by pulling on the end strips 23, 24, generally as depicted in Figure 1, next the splint is applied; then one common strip, say 23, is used to loop the plural filaments 22 over the splint and back into the interproximal spaces, as depicted in Figure 2.

Then the common handling strips 23, 24 are pulled and held and the procedure continued as above described. To remove the filaments after bonding, one common strip is snipped off and the other strip is used to pull the filaments out.

Single monofilaments can be employed in still another beneficial manner in accordance with another aspect of the invention. A condition occasionally encountered is when a posterior tooth is missing. The lack of lateral support for adjacent teeth can, in time, result in the loss of stability. A useful procedure is to splint across the gap to stabilise adjacent teeth as a permanent solution, or, as is more common, as a temporary expedient while a replacement tooth is being fabricated for mounting in the empty space. For permanent splinting, horizontal grooves are often ground along the facial or lingual surfaces for receiving a rigid splint bar which after bonding permanently stabilises the situation. However, this is not very useful as a temporary measure since, when the rigid splint bar is removed, the grooves remain as permanent tooth damage.

In accordance with this aspect of the invention, a flexible splinting material of the type above described can be employed as a temporary splint.

The problem is how to anchor adequately the flexible splint to the adjacent posterior teeth without physically damaging them and in a manner which will allow removal of the splint when the permanent tooth is to be mounted. One suitable method is depicted in Figure 5, which shows an isolated posterior tooth 30 separated by a space 31 from a row of adjacent teeth 32, 33, 34. Monofilaments 35, 36, 37 are inserted as shown and rest on the gingival tissue. Next, a long thin flexible splinting material 38 formed as a ribbon or band is wrapped as shown with its medial portion 39 carried around the distal of the distal tooth 30 of the segment to be splinted, and with the buccal and lingual ribbon ends extending along the corresponding teeth surfaces.Now the first filament 35 is ligated 40 (tied) around the buccal and lingual, overlying, ribbon portions, along the mesial surface of the isolated tooth 30, and the remaining filaments 36, 37 are ligated 41 over both adjacent ribbon portions, and the free ends snipped off, as depicted in Figure 6. This secures the ribbon splint to the teeth and in each interproximal space and presses the ribbon up against the teeth surfaces as in the previous embodiments. The free ends of the splint ribbon can be finished off into an interproximal space.

Next, which is not illustrated, the composite is spread over adjacent tooth surfaces as before, and allowed to harden, stiffening the ribbon and bonding same to abutting teeth. This will adequately stabilise the teeth as a temporary measure pending replacement of the missing tooth. An important advantage of this procedure is that the temporary splint is easily removed by grinding or the like, leaving the basic teeth structure is an undamaged condition.

In the previous embodiments described, the monofilament placement device was separated from the splint. Figures 7-10 illustrate modifications in which the monofilaments are attached to the splint and can perform not only the function of pressing the splint against the teeth during bonding, but also the function of supporting the splint during processing within the patient's mouth or external thereto. This offers the benefits of facilitating handling of the splint, especially if it contains a layer of tacky bonding material, and also reduces the possibility that the loose splint or loose monofilaments may be accidentally dropped while working in the patient's mouth and thus accidentally aspirated by the patient.

In the Figure 7 embodiment, the plural monofilaments 50 have been tacked at medial locations 51 to a mesh-type malleable splint strip 52. By tacking is meant spot bonding using a drop of adhesive between the filament and splint regions tacked together. The splint 52 is now easily manageable by means of the loose filament ends 53. Figure 7 illustrates one or more of the loose ends being handled by the practitioner 54. In one preferred procedure for use with a study model, the splint would first be fitted to the model of the patient's teeth, for example, to trim to the desired length and width and to locate and make any desired V-notches, as described in our U.K.

application, over the interproximai areas. Next, the monofilaments are tacked on using, for example, a cyanoacrylate adhesive at the locations of the interproximal areas of the model. Then, the adjusted splint 52 would be carried to the patient's mouth by means of the attached filaments, and, after a layer of bonding material, liquid adhesive, or creamy composite, were spread over the teeth or on the side of the splint, or on both, is positioned over the teeth segment 56 to be splinted, as illustrated in Figure 8, the monofilaments inserted in the teeth interproximal areas, and then, as described above in connection with Figures 1-3, the filaments used to pull the splint 52 up against the teeth surfaces and into the interproximal areas and held up in that position while the bonding material hardens.

Additional bonding material can be applied to ensure that the mesh interstices are filled, and if necessary excess bonding material removed or spread evenly over the mesh and adjacent tooth surfaces to provide a smooth surface that would be less objectionable to the patient. The mesh impregnated with the hardened bonding material forms the rigid splint desired.

Figure 9 illustrates a modification in which the monofilaments 50 are attached at the approximate interproximal areas by threading each of them through the mesh interstices as illustrated at 57. Figure 10 shows a further modification in which the splint 58 is a perforated malleable strip of thin plastic or metal, and the monofilaments 50 are threaded through the perforations as shown at 59. After the splinting procedure is completed, excess filamentary material is removed by pulling (if the filament does not bond) or by snipping off the loose ends (if they do bond). The filament ends can be loose as depicted, or connected together at one or both ends by a tie strip similarly to that depicted in Figure 4.

Figures 11 and 12 illustrate the inventive principle applied to a bridge or retainer of the "Maryland Bridge" type. The latter is constituted by a retainer of stiff brackets having outwardly extending ears 60 on to which a replacement tooth 61 is mounted. In the procedure, the bridge is lowered into place so that the replacement tooth fills the space 62 of a missing tooth, a while so held the bracket ears 60 are secured as by bonding to the adjacent teeth 63. In the invention, monofilaments 64 are tacked to the bracket ears 60 and the monofilaments used to place the bridge in the correct position and to pull the bracket ears 60 against the adjacent teeth surfaces 63 while the bonding material hardens.In the Figure 1 2 modification, the bracket ears 65 are perforated and the monofilaments 64 are threaded through the perforations as the means of attachment.

Figure 1 3 illustrates another feature of the invention. In the splinting embodiments described herein and in our prior U.K. application, the flexible splint strip is preferably bonded along the inner dental arch. The bonded strip, being thin with a smooth outer surface, is less visible in that position and causes less discomfort to the patient.

However, for posterior teeth, where the splint would be less visible, it can be bonded directly on to the bite surfaces or incisal edge of one or more teeth by means of the liquid adhesive or creamy composite. This is advantageous especially for restorative perio-splinting of weakened or brittle anterior teeth. This brittleness is critical for the incisal edge area of the tooth, which is thinnest and weakest, and thus this edge area is more easily broken while biting. The inventive approach, which is very inexpensive, is to use the flexible or malleable elongated splint in its metal mesh form, and then bend or mould to a kind of slightly angled L-shape for one edge, or a generally U-shape for both edges, and then bond with the bonding material directly over the biting surface of the tooth, or across a row of plural adjacent teeth. This is illustrated in Figure 13 which shows the bent moulded strip 71 bonded over both biting edges 72 of one tooth 73. The impregnated bonded mesh material strengthens or reinforces the incisal edges 72 and reduces the possibility of breakage.

Following bonding, the excess mesh portions are trimmed off and the composite bonded mesh, now stiffened can be shaped by grinding or the like to improve cutting or biting efficiency of the tooth.

Also, it may be necessary to grind down the matching teeth to attain a proper bite. But this technique, inexpensively, will protect the tooth and perhaps save it. Such low-cost restoration procedures as this and the others described above means that proper dental care would be available to lower-income patients who cannot afford the more expensive conventional restorations.

Claims (18)

1. A placement device for use for temporarily holding splinting material against teeth during a splinting procedure characterised in that said device comprises a plurality of monofilaments.

2. A device as claimed in claim 1 characterised in that it includes at least one common strip joining the ends of the monofilaments.

3. A device as claimed in claim 2 wherein the ends are joined so as to be spaced apart by distances approximating the interproximal spacing.

4. A device as claimed in claim 1 wherein the monofilaments are of plastic and have a diameter of about 0.1-1.0 mm.

5. A device as claimed in claim 2 wherein a second common joining strip joins the opposite ends of the filaments.

6. In combination with a dental splinting material for stabilising a patient's mobile tooth or a dental retainer for replacing a missing tooth, multiple spaced monofilaments each attached to spaced regions of the splint or retainer to facilitate placement and bonding of the splint or retainer to the patient's tooth structure.

7. The combination of claim 6 using an elongated malleable splint strip, wherein the attachment points for the monofilaments are spaced apart by distances approximating the interproximal areas.

8. The combination of claim 7 wherein the monofilaments are tacked at a medial region to the splint or retainer.

9. The combination of claim 7 wherein the splint or retainer has perforations, and the monofilaments are threaded through the perforations.

10. A method of stabilising teeth in a teeth segment comprising: a) inserting monofilaments interproximally of the teeth in the segment, b) placing flexible splinting material across the teeth and the said interproximal spaces, c) looping the monofilaments over the splinting material and back into the said interproximal spaces and pulling same so as to draw the splinting material into the said interproximal spaces, and d) applying a hardenable bonding material so as to bond the splinting material to the teeth while temporarily held by the monofilaments, and allowing the material to harden.

11. A method as claimed in claim 10 wherein the monofilaments have a surface that does not adhere to the bonding material and are removed after the bonding material has hardened

12. A method as claimed in claim 10 wherein the monofilaments are joined at opposite ends by common joining strips.

1 3. A method of stabilising teeth comprising: a) inserting monofilaments interproximally of the teeth, b) placing medial portions of a flexible splinting ribbon around one of the teeth and across the facial and lingual teeth surfaces and pulling same so as to draw the splinting material into the said interproximal spaces, c) drawing the monofilaments over the splinting material and pulling same so as to draw the splinting material into the said interproximal spaces, and d) applying a hardenable bonding material so as to bond the splinting material to the teeth while temporarily held by the filaments and allowing the bonding material to harden.

14. A method as claimed in claim 1 3 wherein the monofilaments are ligated around adjacent ribbon portions before applying the hardenable bonding material.

1 5. A novel dental procedure for splinting a patient's teeth of for providing a bridge to replace a missing tooth, comprising the steps: a) attaching multiple monofilaments each to spaced regions of the splint or bridge, b) supporting the splint or bridge by the ends of the monofilaments while positioning the former on the patient's tooth structure, c) using the monofilaments to pull the splint or bridge regions against the patient's teeth while bonding the splint or bridge regions thereto.

1 6. A dental procedure as claimed in claim 15 wherein the monofilaments are tacked or threaded through the splint or bridge, and the splint or bridge is bonded using a liquid or cream bonding material, the excess monofilaments being removed following the bonding step.

17. A novel dental procedure for reinforcing a patient's tooth, comprising the steps: a) bonding a malleable mesh-type elongated strip on to and over the occlusial surface of the tooth, b) trimming off excess strip sections extending beyond the occlusial surfaces, c) adjusting the exposed bonded strip to enhance its biting function.

18. A dental procedure as claimed in claim 1 7 wherein the bonding step is carried out using a liquid or cream bonding material so as to cause the latter to spread through the mesh interstices, and smoothing the bonding material over the strip section overlying the occlusial surface.

1 9. A placement device substantially as herein described with reference to and as shown in the accompanying drawings.