Abstract:
An intraoral device makes a new treatment of dental problems possible. The device includes electronic circuitry, including a proximity detector, a variable time delay, a signal generator and a power supply, to sense and record the frequency and duration of unwanted or undesirable relative positions of body parts within the oral cavity. The recorded data stored by the circuitry enables a dentist to chart the progress of a patient during treatment and diagnose whether functional problems exist which require a specific treatment plan. The undesirable position may be teeth clenched, jaw open with teeth unclenched, tongue pressed against the teeth or a retruded portion of the lower jaw. When these positions have been assumed for too long, a signal reminds the patient. This automatic signal makes it possible for the patient to unlearn bad habits or learn new habits.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to dentistry and specifically to a method, apparatus and monitoring device for the treatment of various problems related to improper use of jaw musculature and/or to monitor a patient&#39;s compliance with his or her treatment regimen. 
     BACKGROUND OF THE INVENTION 
     There are numerous dental problems that arise from improper use of jaw musculature. One of these is clenching, a condition in which a patient constantly or excessively presses his or her teeth against each other. Clenching can cause excessive wear of the teeth, headaches, and fatigue and soreness of the jaw muscles. 
     There are at least three schools of thought on the treatment of clenching. One traditional treatment involves placing a protective layer of acrylic material (called a splint) over the involved teeth. This acrylic layer serves to protect the teeth from direct contact, thus reducing wear, and to spread the load caused by clenching so that it is shared more equally among the neighboring teeth. This reduces wear of the teeth, but the acrylic protective layer does not address the problem of clenching, which frequently continues indefinitely. This forces the patient to wear the splint indefinitely. In some cases the urge to clench is worsened. 
     A second traditional treatment for clenching is occlusal adjustment. This treatment involves selective grinding of teeth so that the load on the teeth caused by clenching is carried evenly by several teeth rather than being concentrated on one or two. This technique is successful with some but not all types of clenching. 
     A third school of thought is that there is nothing that can be done about clenching. This approach may have heretofore had the advantage of candor, but it left patients with unnecessary discomfort. Muscle relaxants are often prescribed in these instances. This group of drugs may adversely effect performance, and therefore can in some instances only be used when the patient is at home. 
     A second class of dental problems relates to what are termed problems in the vertical frame of reference. Examples of these problems are: (1) Dental open bite which is characterized by contact between the posterior teeth without contact between the front teeth when the jaw is closed; (2) skeletal open bite which is characterized by a sloping mandibular plane and a long face; and (3) skeletal deep bite which is characterized by short faces and mandibular planes that are nearly horizontal or parallel with the floor. Skeletal deep bite patients also have dental deep bite which is characterized by excessive overlap of the front teeth. Treatments for problems of this type are discussed below. 
     One method of treating a dental open bite is to mount ceramic magnets on the rearmost molars with like poles facing each other so that the molars are slowly forced more deeply into the bone which supports them. A disadvantage to this method is that the magnets and their acrylic housing force the jaw open 5-6 millimeters in the rear and perhaps twice that at the front. This forces the patient to walk around with his or her mouth open, which is embarrassing and uncomfortable. Patients also have difficulty keeping their jaws in such a position that the repelling magnets are directly opposing one another. Thus, there is a tendency for the lower jaw to slide from side to side and not to stay centered. As a result, these patients are frequently asked to wear a chin strap and headgear apparatus to center the lower jaw. This method of treating open bites is prone to the problem of lack of patient cooperation. 
     Another problem associated with dental open bites is called tongue thrusting. A patient with this problem habitually presses his or her tongue forward against his or her front teeth. This problem can be addressed by placing a cage directly behind the upper or lower front teeth. This appliance restrains the tongue from coming forward where it has forced the front teeth apart. The patient is instructed to keep the tongue behind the cage without touching it and to move the tongue backward, away from the cage whenever it touches the cage. The problem with this appliance is that patients forget to remind themselves to move their tongues backward, and they rest their tongues against the cage. When the appliance comes off, the tongue frequently comes forward to rest against the front teeth again. Relapses frequently occur. 
     When dental open bites are present in patients in their teens, or later as an adult, the treatments for dental open bite are orthodontic treatment in combination with extractions of permanent teeth, or orthodontic treatment in combination with surgery, which usually includes extraction of permanent teeth. 
     Skeletal open bites are traditionally treated by orthodontists through the use of orthodontics, possibly including the extraction of teeth, and using orthopedic force in the form of headgear which imposes an intrusive force to the maxilla and maxillary teeth. Extractions help to solve the problem in a minor way and require the removal of four perfectly good teeth. The successful use of headgear is dependent upon the cooperation of the patient. The headgear includes a brace that circumscribes the head and neck, and it is cumbersome and uncomfortable. Experience has shown that cooperation in wearing the headgear is often less than complete. The use of extractions and headgear treat only the symptoms of skeletal open bites. The underlying cause of the problem which is the lack of sustained contact between the teeth is not addressed by this treatment. 
     Dental and skeletal deep bite are treated by orthodontists through the use of an orthodontic regimen which often includes propping the front teeth open with an acrylic bite plane. This leaves the posterior teeth apart and allows them to erupt into contact with each other. In the short run this treatment appears to be stable, but after about a year the deep bite may begin to return because the underlying cause of the problem (chronic clenching of teeth) was never addressed. 
     Another class of dental problems relates to what is termed problems in the horizontal frame of reference. Mandibular retrognathia is one such problem. It is characterized by the lower jaw being positioned too far behind the upper jaw in the horizontal frame of reference. This condition is conventionally treated with bulky acrylic appliances which hold the lower jaw forward and restrain the lower jaw from moving backward. These appliances have been shown to create undesirable side effects related to this restraint such as proclination of the lower anterior teeth. Other treatments have been: Orthodontics that usually includes extraction of teeth, or orthodontics that utilize orthopedic forces to push the upper jaw backward to meet the lower jaw. If the problem of mandibular retrognathia has not been treated by 12 to 14 years of age, it is often necessary to treat the problem with orthodontics in combination with surgery that is designed to bring the lower jaw forward. 
     Other classes of dental problems arise when patients fail to wear their dental splint, retainer or other corrective dental hardware. Patients, especially younger patients, routinely hinder their treatment program by failing to wear the prescribed dental hardware. When asked, most patients will not confess to the failure to wear their prescribed dental hardware. Accordingly, there is a need for an appliance which can monitor whether a patient is in compliance with his or her prescribed hardware regimen. 
     SUMMARY OF THE INVENTION 
     The present invention provides a new approach to treating and monitoring the dental problems discussed above. The present invention can remind the patient of unconscious, undesirable behavior every time it occurs and can help the patient to learn new habits. In addition, the present invention permits a patient&#39;s treating dentist or orthodontist to monitor the patient&#39;s progress through each patient&#39;s prescribed treatment regimen. This is accomplished by the use of electronic circuitry attached to, e.g., the upper teeth which senses the proximity of the lower teeth and signals the patient when the jaw is in an undesirable position. The circuitry also contains a memory and readout apparatus. The memory and readout apparatus may permit a treating dentist or orthodontist to monitor the amount of time and number of times bite forces exceed a predetermined threshold. In addition, the memory and readout apparatus may permit the monitoring of jaw positions by recording the amount of time the teeth are more than a predetermined distance apart, the amount of time the teeth are together and/or the number of times biting occurs. 
     For patients who clench, the circuitry may sense a closed jaw, and when the jaw has been held closed too long, e.g., 3 or 5 seconds, a signal (be it audible or otherwise) is generated alerting the patient to relax his or her jaw muscles by opening the jaw. Conversely, with open bite patients the circuitry may be arranged to signal and monitor the patient when the jaw has been open too long. Additionally or alternatively the present invention may signal and monitor the patient when his or her tongue is being pressed against the back sides of the front teeth. By providing a signal to the patient at the appropriate time, the patient can modify his or her behavior so that the cause of the patient&#39;s problem can be treated: Clenchers learn to relax their jaw muscles; open bite patients strengthen their jaw muscles; and tongue thrusters learn not to press against their teeth. By monitoring the above conditions the present invention permits a dentist or orthodontist to have an objective means of monitoring and diagnosing the progress (or lack thereof) a patient is making progress in their treatment regimen. 
     This invention may also be adapted to create habits that are lacking by reminding the patient when the desired habit or function is not being practiced. Examples of this application are in the treatment of skeletal open bite or mandibular retrognathia. In skeletal open bite patients there is thought to exist a lack of sustained contact between upper and lower jaws. This results in the tendency for the face to grow downward instead of forward. The result is these patients have extremely long faces. By using the present invention to sense the lack of contact between teeth, the patients can be trained to keep their teeth in contact during certain periods during the day. This stops or reverses the downward growth and at the same time trains the muscles to keep the lower jaw in more frequent contact with the upper jaw. Additionally, the above device can be configured to permit it use in training mandibular retrognathia patients to hold their jaws forward in the correct lower jaw position. 
     The present invention includes an electronic circuit which may comprise a reed switch, time delay, oscillator, signal generator (e.g., a sound production or light emitting device), memory component, readout device and power supply all encapsulated in suitable plastic material (e.g., an acrylic or a watertight synthetic resin) and mounted to a molar, usually a maxillary molar. To treat clenching or open bite problems the opposing molar carries a small magnet to actuate the reed switch. The device is removably mounted to a band surrounding the tooth so that it may readily be removed for repair or when it is not desirable to have it operating. With regard to the readout device, it can be integrated into the device as mounted in the patient&#39;s mouth thereby permitting the doctor to directly monitor the patient&#39;s progress during an office visits. In another embodiment, the device can be set up to include an integrated readout device so as to permit the patient to monitor his or her own progress between office visits. 
     In one embodiment, the device can have connectors which permit a treating dentist or orthodontist to attach a readout device to display the information contained within the device&#39;s memory. In another embodiment, the device can include circuitry which can produce a series of audible beeps which are coded to represent the data contained in the device&#39;s memory. These beeps can be recorded by a device outside the patient&#39;s mouth and then translated to yield the data contained within the device&#39;s memory. 
     In another embodiment, the device can contain circuitry which generates a signal comprising a slight vibration (similar in nature to that of a pager). Such a vibrational mode is advantageous in that it is quite and does not interrupt other individuals in the immediate vicinity of the patient. In another embodiment, the device can contain a means to permit switching between an audible mode and a vibrational mode. 
     To treat tongue thrusting, a cage is mounted just behind the upper front teeth. The cage is movable and spring biased rearwardly to a position slightly spaced from the upper front teeth. When the tongue is pressed against the cage, the cage moves forward. A magnet is mounted to the cage, and when the cage moves, the magnet actuates the circuitry to alert the patient. The tongue thrusting treating device is mounted by means of a pair of polymeric splints which surround the three or four rearmost maxillary teeth on each side and in one of which the circuitry is embedded. The splints are connected by thick wires or bars which are contoured to follow the roof of the mouth. Because tongue thrusting is often accompanied by an open bite, additional circuitry which can be arranged to detect an open bite may also be embedded in one of the polymeric splints. The monitoring function of the present invention enables a treating dentist or orthodontist to monitor the number of times and/or amount of time the tongue is thrust forward. 
     The invention may also be adapted to be incorporated into a retainer or other corrective dental device. In such a situation the monitoring function of the present invention permits a treating dentist or orthodontist to monitor the amount of time the corrective hardware has spent at or above a certain temperature. This enables the treating dentist or orthodontist to ascertain whether such corrective dental appliances have been worn as prescribed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the annexed drawings: 
     FIG. 1 is a side skeletal view showing one embodiment of an intraoral appliance constructed in accordance with the present invention; 
     FIG. 2 is a view looking generally in the direction of arrows  2 — 2  of FIG. 1 but further showing the soft tissues including cheek, tongue, gums and roof of the mouth; 
     FIG. 3A is a schematic illustration of one embodiment of a circuit utilized in the present invention; 
     FIG. 3B is a schematic illustration of another embodiment of a circuit utilized in the present invention; 
     FIG. 4 is a plan view showing a tooth with a band around the tooth for securing an apparatus which forms a part of the present invention; 
     FIG. 5 is an elevation view of the tooth of FIG. 4 with band attached and further showing another component of the present invention prior to installation; 
     FIG. 6 is a view looking in the direction of arrows  6 — 6  of FIG. 5; 
     FIG. 7 is a partly cut away perspective illustration of a second embodiment of the present invention especially adapted to treat tongue thrusting; 
     FIG. 8 is a side elevation view of the apparatus shown in situ in FIG. 7; 
     FIG. 9 is a view generally looking in the direction of arrows  9 — 9  of FIG. 8; 
     FIG. 10 is a view showing another embodiment of a device for monitoring certain conditions in patients win which a readout unit is separate from a monitoring device and circuitry; and 
     FIG. 11 is a view showing one embodiment of a device for monitoring certain conditions in patients in which a readout unit with the monitoring device and circuitry is integrated into an polymeric mouth piece. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The intraoral appliance  10  illustrated in FIGS. 1 and 2 includes an electronic signaling circuit  12  embedded in an polymeric housing  14  (e.g., an acrylic or a watertight synthetic resin). The circuit  12 , which will be described in greater detail below, includes a detector for sensing the relative position of body parts within the oral cavity. In the embodiment illustrated in FIGS. 1 and 2, proximity of the first mandibular molar  22  to the first maxillary molar  24  is sensed by means of a reed switch  16  mounted within the polymeric housing  14  and a magnet  18  embedded in another polymeric housing  20  mounted to the mandibular molar  22 . The polymeric housings  14  and  20  are molded to conform to the particular patient&#39;s morphology, and the circuitry is extremely compact so that the resulting apparatus may be worn without discomfort and discreetly. 
     Where the intraoral appliance  10  is used for the treatment of clenching, the circuitry  12  is configured so that when the mandibular and maxillary molars  22  and  24  are in contact, the reed switch  16  is closed. When the teeth  22  and  24  remain in contact for more than a predetermined length of time (in one embodiment any where from about one to about twenty seconds), a signal is generated which is audible or vibratory to the patient in whose mouth the appliance is installed. By being reminded that his or her jaw is clenched, the patient can break this bad habit and thus alleviate the symptoms it causes. In addition, the intraoral appliance may also contain a clock and counter memories and readout device for monitoring and displaying the position of the upper and lower jaws and the duration that the jaws are clenched, as is discussed below. 
     The circuit  12  includes a detector for detecting the proximity of body parts. In the embodiment of the invention illustrated in FIGS. 1 and 2 the detector comprises the reed switch  16  which is closed by a magnet  18  (FIG.  3 A). When the reed switch  16  is closed, power from a battery  26  flows through a time delay circuit  28 , and after a predetermined length of time (this time being adjustable), power is then passed to an oscillator  30  and from the oscillator  30  to a piezoelectric transducer  32  to alert the patient that he or she is clenching and has been clenching for too long. 
     In addition, the circuit  12  includes clock memory  19 , which records the duration of any number of occurrences, a counter memory  21 , which records, for example, the number of times that the upper and lower jaws are clenched, and a readout  23 . If the device is only being used at night, the memories  19  and  21  can be permanently and directly connected to the readout  23 . Alternatively, the readout  23  can be detachable and is activated when brought into contact with connectors on the circuit  12  (FIG.  10 ). In another embodiment, the readout  23  can contain additional memory for storing data beyond that of memories  19  and  21 . 
     Still another alternative for the readout is that readout  23  receives signals from the piezoelectric transducer  32  and generates a series of tones based upon information stored in the memory sections of circuit  12  (e.g., the clock memory  19  and the counter memory  21 ). These tones would be emitted from circuit  12  when the circuit is prompted. For example, after having removed the intraoral appliance  10  from a patient&#39;s mouth the intraoral appliance  10  could be plugged into a receptacle and activated by another reed switch. The receptacle can in turn be connected to a computer (e.g., a standard desktop or laptop computer) through the computer&#39;s sound card. The computer, through the use of appropriate software, would interpret the sound data generated by circuit  12  of the intraoral appliance  10  and display on the computer&#39;s display the data stored in circuit  12 &#39;s memories (e.g., the duration of any number of occurrences and the number of times that the upper and lower jaws are clenched). 
     In yet another embodiment, the readout  23  can be replaced by a small speaker which contains therein the necessary circuitry to generate a series of audible beeps. When activated as described above or by an appropriate command (e.g., an audible command when a microphone and the necessary circuitry is included in the device), the speaker will generate a series of tones or beeps based upon information stored in the memory sections of circuit  12  or the memory section, if any, of the speaker portion of the device. These tones can either be communicated to a computer as described above or can be recorded using another device (e.g., a tape recorder) and interpreted by any suitable means (such as a computer program). 
     In one embodiment, the readout  23  will be a conventional LCD display with its own power supply which is placed inside the polymeric housing  14 . All of these circuit elements are conventional. It is contemplated that in practice the circuit elements  19 ,  21 ,  28  and  30  will be formed in a single integrated circuit. 
     The strength of the magnetic field surrounding the magnet  18  and its position relative to the reed switch  16  determines when the reed switch will close for treating clenching and cause a clenching incident to be recorded in the counter memory  21  and the time duration of clenching in the clock memory  19 . The magnet  18  should be positioned so that when the teeth  22  and  24  come into contact the magnetic field at the reed switch  16  is just sufficient to close the switch. This is accomplished either by proper selection of the magnet&#39;s size or field strength or by positioning the magnet  18  relative to the reed switch  16 . 
     In one embodiment, for treatments which involve teaching the patient to hold his or her jaw closed, the magnet  18  might be such as to actuate the reed switch  16  when teeth  22  and  24  are close to each other but not yet touching. For such treatments, the clock memory  19  and the counter memory  21  record the amount of time when teeth  22  and  24  are in contact with one another and/or the amount of time when teeth  22  and  24  are more than a predetermined distance apart. Again the information stored in the memories  19  and  21  can be retrieved by either of the above described readout devices. 
     In another embodiment, the reed switch  16  is connected to different parts of the circuit  12  so as to work in a manner diametrically opposed to that of the clenching configuration. That is, the circuit  12  is set up in such a way as to produce a signal (as described above) when the patient opens his or her mouth for a predetermined, adjustable amount of time (e.g., about one to about 20 seconds). In another embodiment, this circuit can also prevent the patient from developing a clenching habit, in view of the prompting to keep their mouth closed, by the inclusion of additional circuitry which is similar in nature to the clenching configuration described above. That is, in one embodiment, the device contains both circuitry to prevent “slack jaw” and to prevent clenching. In this instance the device is adjusted so that the patient can neither clench for too long a period of time or have their mouth open for too long a period of time. In still another embodiment, the clenching portion of the device can be activated only during certain time periods throughout the day (e.g., at night). 
     The time delay circuit  28  provides an adjustable time delay of between approximately zero to twenty seconds. This delay allows the patient to talk, eat, and swallow, all of which require contact between mandibular and maxillary teeth. The length of the time delay may be made variable. This can be done in a number of ways. Either a potentiometer can be used so that the resistance in an R-C circuit may be varied, or electronic components (either resistors or capacitors) could be removed or added to the circuit to achieve the same result. The same result could be obtained digitally with a clock and counter. The length of time would be varied by varying the length of the count. Again, such a circuit is conventional. 
     As discussed above, proximity of the mandibular and maxillary teeth is sensed by means of the detector including the reed switch  16  and magnet  18 . The detector could also be responsive to inductance or capacitance in which case a magnet would not be required but merely a piece of metal, stainless steel, for example. The important thing is not what type of proximity detector is used, but that it be capable of generating a signal when the body parts whose positions are to be detected come into a preselected spatial relation and of stopping the signal once the body parts move to a different position. Further, an advantage to the use of a reed switch/magnet and/or capacitance/inductance detector is that full freedom of movement of the mandible is maintained because there is no mechanical interconnection between the body parts whose position is being detected. 
     The circuit  12  is embedded in an polymeric housing  14  (FIG.  2 ). Similarly, the magnet  18  is embedded in a second polymeric housing  20 . Both of these housings are secured to their respective teeth by means of orthodontic bands  40 ,  42 . The band  40  is illustrated in FIG.  4 . It is formed of a conventional steel alloy which circumscribes the mandibular molar  22 . A U-shaped band  42  extends from the buccal surface of the band  40  and is connected to it by, for example, welding. The loop  42  and band  40  together define an opening  44  which receives a pin  46  (FIG. 5) which extends from the polymeric housing  20 . 
     The pin  46  is L-shaped and projects laterally from the polymeric housing  20  and then downward, the downward leg being proportioned to fit in the opening  44 . A U-shaped wire spring  50  is mounted to the horizontal leg of the pin  46 . The wire spring  50  is mounted horizontally so that its lowermost leg  52  (FIGS. 5 and 6) is slightly above the bottom of the downward leg of pin  46 . As the downward leg of pin  46  is inserted into the opening  44 , the leg  52  of spring  50  encounters a dimple  54  which projects laterally from the outside surface of the loop  42 . The spring  50  yields as the polymeric housing  20  is pushed downward, and ultimately the lowermost leg  52  of the spring snaps under the bottom side of the dimple  54  to hold the polymeric housing  20  firmly in place. There are times when a patient may choose not to have his intraoral appliance operative. In this case, the spring  50  may be easily manipulated to permit the downward leg of pin  46  to be withdrawn from the opening  44 . A similar band and pin arrangement may be used to secure the circuit  12  and the polymeric housing  14  to the maxillary molar  24 . 
     Alternatively, attachment means other than orthodontic bands can be used so long as the attachment means used provide secure and stable positioning of the polymeric housings. 
     The intraoral appliance  10  as illustrated in FIGS. 1-3A and  4 - 6  is configured for the treatment of clenching. Specifically, the circuitry is arranged to generate a signal when mandibular and maxillary molars have been in contact with each other for a period of time which exceeds that required for eating, talking or swallowing. By being reminded of the improper or undesirable action every time it occurs, the patient is able to break bad habits, in this case excessive clenching. 
     In addition, the above described circuitry can be placed into a night guard or splint  100  which can also contain, embedded therein or hardwired thereto, the above described readout device  23  (FIG. 11) for displaying any recorded information. Such a night guard or splint  100  can optionally include a conductive rubber transducer  102  and a bite force memory  25  (FIG. 3A) similar to the clock and counter memories  19  and  21 , respectively, as described above. The conductive rubber transducer  102  permits the treating dentist or orthodontist to monitor a patient&#39;s bite forces. The bite force memory  25  records bite forces that exceed a predetermined threshold. Whereas the clock and counter memories  19  and  21 , respectively, record the amount of time and number of times such bite forces exceed the predetermined threshold. In the case of a patient with an open bite the clock and counter memories  19  and  21 , respectively, record the amount of time and/or number of times the patient&#39;s teeth are out of contact by a predetermined distance. 
     The circuitry  12  may also be arranged to generate a signal when the opposite condition obtains. For a variety of reasons, including the treatment of an open bite, a patient might need to learn to keep the jaw muscles tense. In this case, rather than using a normally open reed switch  16 , a normally closed reed switch is included in the circuit. The effect is that whenever the maxillary and mandibular teeth are out of contact for a length of time which exceeds a predetermined length of time, an audible signal is generated to alert the patient to close his mouth. To treat mandibular retrognathia, the circuitry  12  is arranged as for open bite treatment, but the magnet and reed switch are positioned so that the alarm is quiet only when the jaw is thrust forward. In such a situation the clock and counter memories  19  and  21 , respectively, will record the amount and number of times the distance between the maxillary and mandibular teeth exceeds a predetermined distance, before, during and/or after treatment. 
     In another embodiment, the normally closed reed switch can be eliminated in favor of a different portion of the circuit  12  which is designed to function like a normally closed reed switch. 
     For treatment of mandibular retrognathia, open bite, or other condition where closing the jaw would help in treatment, circuitry arrangements are possible other than that discussed in the preceding paragraph. For example, a normally open reed switch could be used together with a circuit which will actuate the oscillator  30  when the reed switch has been open more than a predetermined length of time. Regardless of which arrangement is used, the patient receives an audible signal whenever his or her jaw has been too long in an undesirable position. Additionally, regardless of which arrangement is used, the clock and counter memories  19  and  21 , respectively, record the amount and number of times the patient&#39;s maxillary and mandibular teeth are more than a predetermined distance apart. The recorded information is displayed either on a readout unit hardwired to the circuitry  12  or a detachable readout unit or an audible readout unit, as described above. 
     For treatment of open bite problems, the circuit  12  illustrated in FIG. 3A includes an additional timer circuit  56  in series with the other circuit elements. The timer circuit  56  is conventional and includes a twenty-four hour clock which is programmed to limit the number of hours or time periods that the circuit  12  operates in the course of a day. This permits the jaw muscles to relax and rest and prevents the creation of a clenching problem. For example, the timer circuit  56  may actuate the circuit  12  only between 7 p.m. and 11 p.m. and may be programmed so that during this four hour period it is on only for alternative 20 minute intervals. Later in treatment, the dentist may want to change the time range to 9 p.m. to 11 p.m., with the circuit on for alternate 15 minute intervals. Alternatively, the circuitry depicted in FIG. 3B (discussed more fully below)can be modified as described above to achieve the same results. 
     In a commercial device, it is contemplated that the timer circuit  56  is integrated into a single chip together with the other circuit elements. The timer circuit  56 , as indicated, is adjustable to control when the circuit  12  is operative. Therefore, the timer circuit  56  may be helpful in the treatment of problems in addition to open bites. 
     A further embodiment of the present invention is illustrated in FIGS. 7-9. Here the purpose is to treat tongue thrusting. Persistent tongue thrusting can result in moving teeth out of their desired alignment. In this case the relative position between the tongue and the incisors is what is being sensed. To achieve this a U-shaped cage  60  is fashioned out of a suitable metal or plastic. The cage  60  includes an upper and lower U-shaped horizontal band  62  and  64 , respectively, interconnected by three vertical braces  66 . The U-shaped members  62  and  64  merge into rods  68  and  70  which extend rearwardly from about the first or second premolar. 
     The rods  68  and  70  slide in bushings  72  (FIG. 8) which are embedded in polymeric housings  74  and  76 . A magnet  18  is mounted to the rearmost end of the rod  68  and a reed switch  16  is embedded in the housing. A spring  80  biases the cage  60  rearwardly and the magnet  18  away from the reed switch  16 . The spring  80  extends between one of the bushings  72  and the magnet  18 . The housing  74  is formed with an appropriate internal cavity  82  which accommodates the movement of the rod  68 , spring  80  and magnet  18 . 
     When the tongue presses toward the inside of the front teeth, the cage  60  is moved forward, taking with it the magnet  18 . This in turn brings the magnet into alignment with the reed switch  16  which is part of the circuit  12 . This circuitry is essentially similar to that illustrated in FIG. 3A for treating clenching in that a signal is produced when the tongue has been pressed forward too long. In addition, as described above the circuitry also includes clock and counter memories  19  and  21 , respectively, and a readout  23  for monitoring the number of times and/or length of time that the cage is within a predetermined distance from the patient&#39;s front teeth and for displaying such information to the treating dentist or orthodontist. 
     The polymeric housing  74  forms a splint covering the rearmost three or four upper teeth. The bushings  72 , spring  80 , magnet  18 , and reed switch  16  are mounted in its lingual side. The circuitry  12 , except for the reed switch  16 , is carried in the buccal side of the splint  74 . The splints  74  and  76  may be interconnected by a plastic arch which conforms to the shape of the palate, or as shown in the drawings, by a pair of wires  84 ,  86  and interconnecting ring  88 . 
     The splint arrangement shown in FIG. 7 may be also used with the type of circuitry intended to treat clenching or in the alternative an open bite. In this case the upper band  42  (FIG. 2) would be eliminated while the lower band  40  would be retained to mount the magnet  18 . Whether the splints  74  and  76  (FIG. 7) are used to secure the circuitry or an orthodontic band (e.g.,  42 , FIG. 2) depends on individual morphology and/or conditions present in the particular patient. 
     In some circumstances it might be useful to have a signal generated both when the tongue is thrust forward and when the jaw is slackened. In this case the polymeric splint  76  could contain circuitry like that discussed in connection with FIGS. 1-3A and an additional magnet would be attached to a mandibular tooth to actuate the circuitry. Such an arrangement could provide one signal when the tongue was thrust forward and a different and independent signal when the jaw has been excessively open. Again as described above, the circuitry  12  contains the necessary memory blocks in order to record the appropriate information for later retrieval by the treating dentist or orthodontist. 
     Once the patient has learned to keep his or her jaw tight and tongue relaxed, conventional orthodontia may be used to pull the teeth into proper alignment with the confidence that bad muscle habits will not undo what the orthodontia can achieve. As a further and optional feature, the circuit  12  (FIGS. 3A and 7) may include a memory and readout device  90 . This device would record the patient&#39;s progress by measuring the number of times the tone generator  32  was actuated and for how long. The circuit  12  also includes means for permitting the dentist to read the stored information and displaying it, for example, on a computer screen or a computer controlled printer. 
     The connection between the memory and readout device  90  and the dentist&#39;s computer could be a direct electrical connection through a jack in the device  90  (shown schematically at  91 ) or it could be an inductive or capacitive connection. Such memories and readout devices are well known in the medical electronics field and are used extensively in cardiac pacemakers. If the circuit  12  is made with the memory and readout device  90 , it is contemplated that it be integrated with the other circuit elements into a single integrated circuit. 
     In addition, the memories contained within the circuitry of the present invention can record a wide variety of data. For example, instead of the counter memory recording the number of times a specified condition occurs, the clock and counter memories  19  and  21 , respectively, can be converted into memory for recording and tracking the temperature of the dental appliance above a predetermined threshold over any given time interval. This permits a treating dentist or orthodontist to determine if the patient is wearing his/her dental appliance as prescribed. 
     Another embodiment of circuitry for use in the present invention is shown in FIG.  3 B. The circuit shown in FIG. 3B can, with any of the above described modifications, be used in any or all of the embodiments described above. 
     As seen in FIG. 3B, circuit  200  contains a battery  26  which is connected to a conductive rubber transducer  102  which acts as a force transducer and permits the measurement of a patient&#39;s bite forces. The rubber transducer  102  is connected to an amplifier  112  which has a feed back loop  114 . The amplifier  112  is also connected to a reed switch  16  which is closed by a magnet  18 . In one embodiment, circuit  200  only measures a patient&#39;s bite forces when the reed switch  16  is closed. 
     However, the circuit  200  may be configured in order to constantly monitor a patient&#39;s bite forces by deletion of the reed switch  16  and the magnet  18 . 
     The amount of voltage generated by the circuit  200  is directly proportional to the amount of bite force exerted on the rubber transducer  102 . The feed back loop  114  acts to prevent a voltage spike from damaging the circuit  200 . The reed switch  18  is connected to a voltage detector  116  which measures the amount transmitted by the battery  26  and the amplifier  112  when the reed switch  16  is closed due to the proximity of the magnet  18 . 
     Voltage detector  116  is further connected to a time delay circuit  28 , and after a predetermined length of time, power is then passed to an oscillator  30  and from the oscillator  30  to a one shot  126  and then to a signal generator  128 . Voltage is then passed from the signal generator  128  to a piezoelectric transducer  32  to alert the patient that his or her bite forces exceed a predetermined amount. In the case where the reed switch  16  and the magnet  18  are present the circuit  200  can also monitor whether or not and for how long a patient is clenching in the manner described above with regard to circuit  12 . 
     The one shot  126  is, in one embodiment, a twenty (20) second one shot. Once the frequency generated by the oscillator  30  exceeds, for example, a predetermined level the one shot  126  is activated and moves into a second state which in turn activates the signal generator  128  so as to signal the patient that he or she is either clenching, exceeding a predetermined bite force, or both depending upon the signal generated by the signal generator  128 . Once the one shot returns to its initial state, it ceases to signal to the patient. In this connection, the patient signaling device, being piezo electric, may generate an audible signal or merely a vibration that the patient can feel. Alternatively, any device which generates a recognizable sensation may be used, including a mild electric shock or a slight temperature change. 
     The one shot  126  stays in this second state for 20 seconds (i.e., a twenty second one shot) irrespective of the input from the oscillator. After the 20 seconds has elapsed the one shot will return to its initial state so long as the frequency from the oscillator does not meet the criteria set for switching the one shot into its second state. 
     Furthermore, as can be seen in FIG. 3B, the voltage detector  116  is also connected to a memory readout controller  118 . The memory readout controller  118  is further connected to memories  120  and  122 . The memories  120  and  122 , in conjunction with the memory readout controller  118 , record the bite force levels and the number of clenching events, respectively. Alternatively, the memories  120  and  122  can record other events or data such as temperature, position data, tongue thrusting events, etc. as described above with regard to clock and counter memories  19  and  21 . 
     In addition, the circuit  200  includes a readout  124 . If the device is only being used at night, the memories  120  and  122  can be permanently and directly connected to a readout  124 . Alternatively, the readout  124  can be detachable and is activated when brought into contact with connectors on the circuit  200  (FIG.  10 ). In one embodiment, the readout  124  will be a conventional LCD display with its own power supply. All of these circuit elements are conventional. It is contemplated that in practice the circuit elements  28 ,  30 ,  112 ,  114 ,  116 ,  118 ,  120  and  122  will be formed in a single integrated circuit. 
     Alternatively, readout  124  can be similar in nature to readout  23  as described above. 
     The strength of the magnetic field surrounding the magnet  18  and its position relative to the reed switch  16  determines when the reed switch will close for treating clenching and cause a clenching incident to be recorded in the memory  122 . The magnet  18  should be positioned so that when the teeth  22  and  24  come into contact the magnetic field at the reed switch  16  is just sufficient to close the switch. This is accomplished either by proper selection of the magnet&#39;s size or field strength or by positioning the magnet  18  relative to the reed switch  16 . 
     For treatments which involve teaching the patient to hold his or her jaw closed, the magnet  18  might be such as to actuate the reed switch when teeth  22  and  24  are close to each other but not yet touching. For such treatments, the memory  122  can be configured to record the amount of time when teeth  22  and  24  are in contact with one another and/or the amount of time when teeth  22  and  24  are more than a predetermined distance apart. Again the information stored in memories  122  can be retrieved by either of the above described readout devices. 
     In another embodiment, the normally closed reed switch can be eliminated in favor of a different portion of the circuit  200  which is designed to function like a normally closed reed switch. 
     The time delay circuit  28  provides an adjustable time delay of between zero and about twenty seconds. This delay allows the patient to talk, eat, and swallow, all of which require contact between mandibular and maxillary teeth. The length of the time delay may be made variable. This can be done in a number of ways. Either a potentiometer can be used so that the resistance in an R-C circuit may be varied, or electronic components (either resistors or capacitors) could be removed or added to the circuit to achieve the same result. The same result could be obtained digitally with a clock and counter. The length of time would be varied by varying the length of the count. Again, such a circuit is conventional. 
     As discussed above, circuit  200  can be modified in the same manner as circuit  12  in order to allow for its use in determining any of the occurrences or conditions discussed above in connection with circuit  12 . 
     Thus, it is clear that the present invention provides a new approach to treating both clenching, open bite/tongue thrusting and retrognathia problems. The electronic circuitry  12  or  200  may be attached to the upper teeth as in FIGS. 2 and 7 to sense the proximity of the lower teeth and to signal the patient when the jaw or tongue are in an undesirable position. For patients who clench, the circuitry  12  or  200  senses a closed jaw, and when the jaw has been held closed too long, a signal sounds alerting the patient to relax his or her jaw muscles. With open bite patients the circuitry  12  is arranged to signal the patient when the jaw has been open too long, and in the embodiment of FIGS. 7-9 the patient is signaled when his or her tongue is being pressed against the back sides of the front teeth. By providing a signal to the patient at the appropriate time, the patient can modify his or her behavior so that the cause of the patient&#39;s problem can be treated rather than merely the dental symptoms. Additionally, by providing data concerning the occurrence and duration of certain conditions in the mouth, the treating dentist or orthodontist is better able to determine what if any progress has been made and therefore recommend what further treatment, if any, is necessary. Also this information can be used to gather objective diagnostic data in order to determine a course of treatment.