12 - MANDIBULAR STRETCHING

Daniele Tonlorenzi - Luca Martinelli

Mandibular stretching

Publication no. 12 - 09 November 2012

 1. STRETCHING

1.1 Muscle stretching

Stretching is a method of muscle lengthening already widely known in traditional medicine. It is used largely in the post-operative rehabilitation and most people knows it for its applications in sports; muscle stretching, in fact, allows you to make movements more easily, with a greater amplitude, while, of course, prevent tearing.

Up to now the most used two kinds of stretching are: the static stretching, where it is hold a fixed position keeping the muscle stretched for a few seconds, and the dynamic stretching, where opening and closing movements of the articulation are repeatedly made in an effort to propel the muscle into the maximum possible extension range, then returning to the rest position.

1.2 Dental stretching (mandibular stretching)

In dentistry muscle stretching is named "Mandibular stretching". The mandible is in fact involved in a static or dynamic stretching exercise, but it would be better to say that the elevator muscles (masseter and temporal) are those involved to allow the opening-closing movement of the mouth.

In this specialized discipline, stretching is used for a long time indeed, while remaining mostly unknown to the vast majority of operators and patients.

The stretching can be done even without aids, but experience has taught us that you cannot get the hoped benefit, and in a short time, because it is not a practice easy to control and to be understood by the patient. Figure 1 shows the representation of a static stretching exercise done by the patient.

Fig. 1

2. MEDICAL DEVICES FOR MANDIBULAR STRETCHING

To achieve the wanted effect many devices have been invented over the years to perform assisted stretching, which is a kind of device that helps the patient to the proper execution of stretching. They can be summarized in three main types:

2.1. Bite

Perhaps the most known device in absolute, a sort of “bite” (built with a precise height in order to obtain the muscle elongation) to be kept in mouth during the day or more easily during the night for the execution of the static stretching. Generally made of resin, it is a device specially made for each patient; Fig 2 shows a kind of bite.

Fig. 2

2.2 Distracting splint

Surely less known, it is very similar to the "orthodontic device for  children". This one is used to run the dynamic mandibular stretching. 

It is made of resin and is provided with springs that allow the opening and closing of the mouth: it permits to perform a dynamic mandibular stretching. 

Even in this case we refer to devices made only and exclusively for a patient; Figure 3 shows some examples.

The selection shows the splints by Rampello-Di Paola-Roncallo and Rocabado

Fig. 3

2.3 Industrial device

The last but not the least, we have a manufactured device, which allows performing mandibular stretching exercises indistinctly to any patient. 

Originally born for post-operative rehabilitations, it is used nowadays to exploit at most all the benefits coming from mandibular stretching. 

With these devices you can perform both dynamic and static stretching even if, being able to choose, it is definitely more advantageous to perform the dynamic exercise. 

There are several types of mandibular stretching. The best known, protected by patents, are the "THERABITE" by Swedish company ATOS MEDICAL AB (Fig. 4) and the "SPRING DEVICE" by Italian QUASAR DENTAL EQUIPMENT (Fig. 5).

             Fig. 4 - "Therabite"                            Fig. 5 - "Spring Device" 

3. THE MANDIBULAR STRETCHING EFFECTS

A considerable amount of literature have been written on the effects of stretching in general, and of mandibular stretching in particular. Anyone can very easily access plenty of information on the internet: authors and different works done, from the most unknown to the most authoritative, from Bachelor's thesis, to monographs, up to texts.

At the end of this short informative text we will report, as an example but not limited to, a part of bibliographic references that are available on stretching.

It is important to underline that if you want to consult the bibliography, you must search the one about the stretching and not the one about the devices that allow its execution; benefits derive from the mandibular stretching exercise. The devices are only a mean to run it in an assisted way, that is to facilitate the execution to both the doctor and patient.

We remind that systems such as bites or distraction splints are customized medical devices on which a wide literature about construction criteria and use is available.

The industrial devices, such as the Therabite and the Spring Device, are CE marked and registered to the Ministry of the Country of their origin. For these, more than a literature search, it could be useful a functional or economic evaluation on which one is the easiest to use or which one, for example, has got a lower cost of purchasing and maintenance and therefore which is the most  accessible to the dentist and/or the patient.

We could briefly summarize the effects that can be achieved with the stretching in a list that we will show here after, referring to the use of industrialized devices, because they are those we could consider the most flexible and the best suitable for random or repetitive cycles of mandibular stretching.

1 - Trismus and/or mandibular hypomobility treatment;

2 - Pain and temporomandibular disorders treatment in patients undergoing orthodontic treatment, on which you can not use bite for the presence of dental attachments;

3 - Pain and inflammation of muscles and of the temporomandibular joint, prevention of cartilage degeneration treatment;

4 - Muscular relaxation therapy to facilitate the registration of the intermaxillary relations, to promote the prosthetic treatment, bite etc..;

5 - Pre-extraction preventive treatment (dental avulsion);

6 - Therapy treatment after maxillofacial surgery;

7 - Care and treatment of bruxism;

8 - Physiological reduction of stress.

3.1 Some examples of how to use mass production muscle stretching devices

It can’t be ignored that we can’t be "impartial" in discussing the devices mass producted and in fact we will present the use opportunities of the Spring Device, however, for intellectual honesty, we must again point out that attention should focus on mandibular stretching and on the benefical effects that this has on the patient and not on the device that allows the assisted exercise; beyond all technical, functional and economic features, all devices with the same intended use may in fact be suited.

But let's see the method of use:

At first it is recommended to use the device for a few minutes (e.g. two minutes) gradually increasing the time of use.

Therapy, exercise, must be interrupted in case of pain on the patient. The exercises then can be resumed gradually after a short period of time established by the dentist.

3.2 In study

All those who live the experience of dental care with particular physiological stress can obtain a physiological reduction of this, in practice it has the same type of effect given by the stress ball to be squeezed in hand, but much more efficient, which will make the patient more tractable allowing him at the same time a greater ability to keep the mouth open.

This allows a state of well-being, of mental and physical balance, a state that, in dentistry, must always be the centre of attention.

If then the dentist is late for the patient's appointment, prior use of the device allows him to still start the session at the appointed time, with the next patient.

So the dentist earns those 10/20 minutes that allows him to reduce the delay and to avoid giving the impression of neglecting the patient in favour of another one.

3.3 Use of the device at home for a short period (7-10 days)

In this case it is recommended a cycle of stretching exercises for at least three times a day, the duration of ten minutes each, for a week prior to surgery, when it is necessary that the mouth:
- gets greater muscle elasticity, facilitating prolonged dental sessions. Guided implantology, complex or multiple dental extractions;
- increases its opening with advantage for the patient (who suffers less) and for the dentist (that works in a better way);

- increases the opening capacity to make easier and correct the detection of vertical dimensions and especially where there is the need to recover a space that in the patient has decreased over time;

- sllows more easily to the neuromuscular system to "accept" a new vertical dimension (new prosthesis) or changes to the interdental spacing (e.g. bite).

3.4 Use of the device at home for a long period also in association with a bite

Always be carried out at least three times a day for 10 minutes. The guidelines are:

- The presence of pain in the temporomandibular joint.

We recall that the guidelines of the American Academy of Orofacial Pain recommend, as already mentioned, a multidisciplinary approach to temporomandibular disorder (TMD).

The recommendation of the Academy is to combine the bite to physiotherapy; the "spring device" increases the compliance.

This combination is of particular importance in the presence of bruxism.

- Prolonged use in preventive orthodontics, especially for adults, particularly whenever a certain muscle contracture occurs. The onset of pain complicates the case, due to the impossibility of using a bite in the presence of orthodontic attachments.

- Trismus or hypomobility post Maxillofacial therapy, a patient suffering from these disorders shall be subjected to guided therapy, perhaps with periodic check-ups, to relax the muscles and increase joint mobility.

In the case of prolonged treatment over time (several months) it may be considered the possibility of reducing the frequency of the exercises.

To all this we add that this activity also plays a preventive role in the degeneration of the TMJ's cartilage.

But all this can perhaps be summarized into a table (Fig. 6) that as the directions shown so far is always to be considered by way of an example.

Fig. 6

4. SPRING DEVICE - INSTRUCTIONS FOR USE

4.1 Spring Device

The spring device is made of stainless steel (a-Fig. 7) at its ends there are two half-moon-shaped base plates (c - Fig 7) on which are located two bases made of silicon (d - Fig 7) upon which the teeth rest. 
The silicon base are can be disinfected and sterilized (autoclavable) and so reusable.

Fig.7

4.2 Instructions for use
Take the bases (1-fig. 8) and apply the base on the device "half-moons" (2 - Fig 8).

Fig. 8

Insert the device in the mouth (Fig. 9) and begin the exercise involving closing-opening-closing of the jaw.

Fig. 9

5. CONTRAINDICATIONS

Mandibular stretching and especially the use of mass production devices is contraindicated in cases of:

5.1 Patients with bone disease of the jaw or mandible e.g.:
1 - Fracture, even suspected of the jaw or mandible;
2- Infections, e.g. osteomyelitis;
3 - Damage caused by osteoradionecrosis.

  

5.2 Patients with dental problems:

Before using the device it is important to exclude the presence of dental problems such as:

1 - Anterior teeth broken, since the closure of the mouth on the device may cause or facilitate the final rupture, it is true that the force applied to the "bites" of the device is almost certainly greater than that exerted during normal chewing hard foods (e.g. bread or meat), anyway it is good to be cautious;

2 - Presence of fixed prostheses cemented with a temporary cement to prevent its detachment;

3 - Presence of teeth with large restorations (perhaps already damaged) as they could get broken.

5.3 Presence of periodontal disease:

In the case of mobile teeth there is a risk that they may fall.

It is a good practice then assess the stability of any ceramics fixed prosthesis.

   

6.CONCLUSIONS

Static mandibular stretching and even more the dynamic one take advantages to both the patient and the dentist.

The improved mandibular mobility, muscle deprogramming, the joint movement, are all results that give proved benefits to the patient in terms of pain relief, improved mood and improved dental treatments.

Even the dentist benefits from mandibular stretching carried out on the patient, as it is an aid during everyday practices, with a patient more treatable, and in all the therapies in which it can relieve pain, get more space and allow for a possible correction of the therapy in place.

The use of medical devices in series for mandibular stretching facilitates the application of the exercises for all patients, without distinction, these devices can be used both by dentist and patient with extreme flexibility in use, time and place of execution.

7 BLIOGRAPHY (annotated)

As mentioned by way of example, but not limited to, we list a few authors who have dealt with stretching.

Collana di Odontoiatria Pratica Progressi in odontoiatria vol. 3 Mario Molina Domenico Viscuso Gnatologia Stato dell’arte sui disturbi cranio-mandibolari UTET. Mandibular stretching in this book is discussed in detail, but there are no references to the international literature. Here are a few extracts.

The treatment of myofascial pain from trigger points, as well as in the identification and elimination of the causes, consists in stretching of the affected muscles.

Stretching can be done in the following ways:

- Self stretching, in which the patient performs exercises at home (in Figure 5 it is explained it must be applied on masseter and temporal), a)

- assisted stretching, in which the therapist performs the muscular stretching manoeuvres

- stretching and spray, in which the therapist combines to the elongation of the muscle, the surface spraying of the contracted tract with ethyl chloride;

- stretching combined with anaesthetic infiltration, in which the therapist stretches the muscle, immediately after injecting local anaesthetic in the contracted tract. Page 109

………Furthermore after studies (Palla, 2001) it was shown that it is useful to subject the patient to any physio-therapy treatment rather than leave him without assistance. b) Although well-controlled clinical trials have not yet been published, it is recognized as an effective and conservative treatment method. As already mentioned, it is useful that the patient is trained to perform himself at home the treatment modes, so that it becomes independent. This is also a great benefit from the psychological point of view. Page 117

…………Stretching exercises are useful for treating hardened and painful muscles and improve their relaxation (delayed muscle pain, splinting, contracture, trigger points). b) They also increase the radius of the movements of the joints. c)

To obtain muscle relaxation, a proven result can be achieved by forcing the opening of the mouth against the resistance given by the fist placed under the chin. In this case it is exploited the principle of reciprocal innervation. To improve muscle strength stabilization and isometric exercises are recommended, during them an action is exerted against the fingers which push in an opposite direction........ d)
The coordination exercises are used to achieve a coordinated and rhythmic muscle function. They are good in the case of subluxation of an hypermobile TMJ. They are even effective on patients who show deviations in the execution of movements due to muscle hyperactivity ………

Many patients do not do the exercises if this increases the pain. In such cases, the physician must first obtain a relief in symptoms through other means (plates, drugs or behavioural advice). Once the patient has achieved a good result, the treatment plan should be reassessed and modified over time to maintain optimal function. In any case we do not recommend to provide the patient with a complicated exercise program and/or a program requiring too much time to be executed, because there is the risk that the patient gets tired and does not perform as specified. We think that one or two exercises are the best choice. e)

These techniques are similar to those used for muscle stretching and consist of forced movements of opening and laterality of the jaw by both the therapist that self-administered by the patient .....

Although such manoeuvres definitely increase the radius of the mouth opening, it seems that a complete anatomical reduction of the disc is not obtained (Okeson 1966). Obviously passive movements must be performed by either the operator and the patient after TMJ surgery, such as those carried out on other joints of the human body. f)

From the book by S. Palla "Mioartropatie del sistema masticatorio e dolori orofacciali” RC Libri 2001

Physiotherapy treatment page 357

The physiotherapy is widely used in the treatment of almost all rheumatic diseases. Physiotherapy measures are not to be considered secondary or supporting therapies, but are an integral part of the overall treatment plan. They are recommended by several Authors also as therapy of myo-arthropathies, which are considered, as said, rheumatic diseases. d)

1. Burgess JA, Sommers EE, Truelove EL, et a/. Short-term effect of two therapeutic methods on myofascial pain and dysfunction of the masticatory system. J Prosthet Dent 1988; 60:606-610.

2. Clark GT, Adachi NY, Dornan MR. Physical medicine procedures affect tempomandibular disorder: a review. J Am Dent Assoc 1990; 121: 151-162

3. Selby A. Physiotherapy in the management of temporomandibular disorders. Aust Dent J 1985; 30: 273-280.

4. Sturdivant J, Fricton_JR. Physical therapy for temporomandibular disorders and orofacial pain. Curr Opin Dent 1991;1:485-496.

5. Zarb GA, Carlsson GE, Rugh JD. Clinical management. In: Zarb GA. Carlsson GE, Sessle BJ, et al. (eds). Temporomandibular joint and masticatory muscle disorders. Copenhagen Munksgaar d, 1994; 529-548.

Despite the lack of scientific evidence about the therapeutic validity of physical therapy (see below), the self-treatment of the patient with exercises and physiotherapy mode is deemed, by our school, very important since the patient is involved from the outset in the treatment and becomes co-responsible for his recovery. In addition, also based on the results of a study (Feine JS, Lund JP. An assessment of the efficacy of physical therapy and physical modalities for the control of chronic muscoloskeletal pain. Pain 1997; 71: 5-23.), it is appropriate to subject the patient to any physiotherapy treatment rather than leaving him with no "attentions".

The aims of physiotherapy treatment are:

1. pain control;

2. decrease in the tone and lengthening of shortened masticatory muscles;

3. mobilization of hypomobile joints. d)

These results are achieved with:

1.thermotherapy;

2.massage;

3.stretching exercises:

4.stabilization and coordination exercises;

5. mobilization exercises.

Even stretching exercises are intended to decrease the muscle tone and are particularly effective when the musculature is previously contracted (post-isometric stretching. g)

Lewit K, Simons DG. Myofascial pain: relief by post-isometric relaxation. Arch Phys Med Rehabil 1984; 65: 452-456.

There are three types of techniques:

1. ballistic stretching;

2. static stretching;

3. contraction-relaxation stretching or contraction-relaxation-contraction of the agonist muscle; the latter technique is often called Proprioceptive Neuromuscular Facilitation (PNF) g)

  Anderson B, Burke ER. Scientific, medical, and practical aspects of stretching. Clin Sports Med 1991; 10: 63-86.

· Magnusson SP. Passive properties of human skeletal muscle during stretch maneuvers. A review. Scand J Med Sci Sports.

In the static stretching the muscle is stretched as much as possible and hold in this position for 15/30 sec. The PNF technique is based on the principle of reciprocal innervation: the muscle is stretched and at the same time contracted for 6/8 sec. to 50 - 100% of the maximum value. The contraction is followed by a new stretching phase.

Stretching exercises, i.e. lengthening of the muscles, is a practice commonly used to treat hardened and painful muscles, to improve sports performance, prevent muscle injuries, to reduce muscle soreness after exercise and to increase the width of the movement. d)

 · Lewit K, Simons DG. Myofascial pain: relief by post-isometric relaxation. Arch Phys Med Rehabil 1984; 65: 452-456.

· Magnusson SP. Passive properties of human skeletal muscle during stretch maneuvers. A review. Scand J Med Sci Sports 1998; 8: 65-67

Regardless of what mentioned above, the evidence that stretching exercises are effective on pain is rather weak, at least for the delayed or post-exercise muscle soreness.

It is found, however, that the stretching exercises increase the amplitude of the movement c); this increase was attributed to a decreased inhibition of muscular resistance to stretching, to a change in the mechanical properties of muscle tissue and to a greater tolerance of the patient to the stretching itself: the latter case seems to be the most likely. The PNF technique is the one allowing greater muscle elongation and, therefore, greater increase in the amplitude of the movement.

· Halbertsma JP, Goeken LN. Stretching exercises: effect on passive extensibility and stiffness in short hamstrings of healthy subjects (see comments). Arch Phys Med Rehabil 1994,75:976-981.

· Magnusson SP. Passive properties of human skeletal muscle during stretch maneuvers. A review. Scand J Med Sci Sports.

An extensive literature search, conducted according to scientific standards, on the effectiveness of various physiotherapy modes for the treatment of certain forms of musculoskeletal pain, including those due to myo-arthropathy, came to the following conclusions:

• All treatments assessed have not result in an improvement in symptoms of chronic musculoskeletal pain or quality of patient's life able to outlast the period of treatment: the patient then gets a short-term benefit from most of physiotherapy measures; h)

• talking about long-term, the success of physiotherapy is not higher than that of a placebo treatment;

• by increasing the number of treatment sessions more satisfactory results are obtained; i)

• patients derive greater benefit in case they are subjected to any physiotherapy treatment than otherwise. J)

Feine JS, Lund JP. An assessment of the efficacy of physical therapy and physical modalities for the control of chronic muscoloskeletal pain. Pain 1997; 71: 5-23.

From these results it can be inferred that all therapeutic modalities produce their beneficial effect through a multiple action mechanism which reduces fear, depression and anxiety:

Malone MD, Strube MJ, Scogin FR. Meta-analysis of non-medical treatments for chronic pain (published erratum appears in Pain 1989 Apr;37(I):1281(see comments). Pain 1988; 34:23]1-244.

Patients may feel less pain, engaging and focusing on other things, if fully informed and reassured about their current situation and their future. k)

Feine JS, Lund JP. An assessment of the efficacy of physical therapy and physical modalities for the control of chronic muscoloskeletal pain. Pain 1997; 71: 5-23.)

It is known that, by diverting attention away from the pain, the latter decreases in intensity. k) k)

· Bushnell MC, Duncan GH, Chen JI, et al. Non-invasive brain imaging during experimental and clinical pain. In: Devor M. Rowbotham MC, Wiesenfeld-Hallin Z (eds). Proceedings of the 9th world congress on pain (Progress in pain research and management, Vol 16). Seattle: IASP Press, 2000; 485-495

· Wall PD. Pain in context: the intellectual roots of pain research and therapy. In: Devor M, Rowbotham MC, Wiesenfeld-Hallin Z (eds). Proceedings of the 9th world congress on pain (Progress in pain research and management, Vol 16). Seattle: IASP Press ,2000; 19-33

Chapter tile: "Stretching exercises and mobilization" on page 396 (bibliography below)

Stretching and mobilization exercises are indicated:

· as a therapy, in cases of mandibular hypomobility;

· as prophylaxis of patients with partially movable joint and also in patients having trouble in keeping the mouth open or who can not open it sufficiently during dental therapy.

The patient is asked to open the mouth fully, six times per day for six consecutive times, holding this position for at least ten seconds (fig. 6 adn 7 page 397). For patients who have difficulty in holding the mouth open, it can be effective to perform stretching between by inserting between the incisors a series of overlapping wooden paddles, many as they can be moved back and forth with the mouth fully open (fig. 7). The exercise is performed properly when the paddles are not bitten.

If you want to reach a larger opening of the mouth through a post-isometric stretching it is necessary:

· to bite the paddles for six seconds with light pressure;

· relax muscles;

· when the relaxation occurred, open the mouth to the maximum;

· as soon as possible introduce a new paddle.

Repeat this exercise three or four times.

Bibliography:

1. Evjenth O, Hamberg J. Muscle stretching in manual therapy. A clinical manual. Vol II. The spinal column and the temporomandibular joint. Alfta: Alfta Rehab Forlag, 1984, 88-95.

2. Feldenkrais M. Awareness through movement. New York: Harpers and Row, 1972.

3. Kaltenborn FM. Manuelle Mobilisation der Extremitaten-gelenke. 9 ed. Oslo: Olaf Norlis Bokhandel, 1992; 114-179.

4. Maitland GD. Peripheral manipulation. 3 ed. Oxford: Butterworth-Heinemann, I 991.

5. Maitland GD. Manipulation der peripheren Gelenke. 2 ed. Berlin: Springer Verlag, 1996. 538-547

6. Capurso u, Marini I, Bonetti GA. I disordini craniomandibolari. Fisioterapia speciale stomatognatica. Bologna: Edizioni Martina, 1996.

7. Gerritsen GwJ. Physiotherapie bei patienten mit Beschwerden des Kauapparates auf Grund einer myogenen Fehlfunktion. In: Steenks MH, de Wijer A (eds). Kiefergelenkfunktionen aus physiotherapeutischer und zahnmedizinischer Sicht. Diagnose und Therapie. Berlin: Quintessenz, I99l; 133-142.

8. Hansson T, Honée W, Hesse J. Funktionsstòrungen im Kausystem. Heidelberg: Dr. A. Hùthig Verlag, 1987.

9. Hansson TL, Christensen CA, Taylor DLW. Physical therapy in craniomandibular disorders. Chicago: Quintessence, 1992.

10. Klein-Vogelbach S. Therapeutische Ubungen zur funktionellen Bewegungslehre. 3 ed. Berlin: Springer Verlag, 1993; 164-167.

11. Kraus S.L. TMJ disorders. Management of the craniomandibular complex. NewYork: Churcill Livingstone, 1988; 139-173.

12. Langedoen-Sertel J. Die Bedeutung des retrodiskalen Gewebe bei temporo-mandibulàren Arthropathien. Manuelle Therapy 1998;2: 8-4.

13. Langedoen J, Múller J, Jull GA. Retrodiscal tissue of the temporomandibular joint: clinical anatomy and its role in the diagnosis and treatment of arthropathies. Manual therapy 1997; 2: 191-198

14. Langendoen- Sertel J. Physiotherapie und MRT Funktionsdiagnostik einer intraartikulàren Kiefergelenksdyfunktion. Manuelle Medizin 1997; 6: 319-321.

15. McKenzie RA. The cervical and thoracic spine. Mechanical diagnosis and therapy. Waikanae (NZ): Spinal publications, 1992.

16. McKenzie RA. Treat your own neck. 3 ed.Waikanae (NZ): Spinal Publications, 1996.

17. Simons DG, Travell JG, Simons LS. Myofascial pain and dysfunction. The trigger point manual. Volume 1. Upper half of body. 2 ed. Baltimore: Williams & Williams, 1999; 237 -415 .

Considerations regarding the manual stretching technique

a) All authors recommending the stretching do meant it limited to the practice in the dental office, but recommend it also at the patient's home, so that he is trained to become independent in pain control. This is also a great benefit from the psychological point of view. It is therefore an harmless practice, in all the bibliography cited above any case of unfavourable, neither serious nor mild event is cited.

b) Although not playing a fundamental role in pain therapy it is a valuable therapeutic aid when integrated in the dental treatment of temporomandibular joint pain.

c) It increases considerably the radius of the movements of the joints (stretching) increasing the opening of the mouth. It controls the pain. This is an undoubted benefit because it allows the dentist to work more efficiently in any situation (conservative, endodontics, surgery, implants, etc.). At the same time it reduces the fatigue of the patient and the risk that holding the mouth open for a long time could induce the appearance or worsening of muscle pain. In the case of dental extractions consider that in addition to being a long time with his mouth open, also a strong asymmetric force is exerted in the patient's mouth, and all result in the onset of pain in the muscles of the masticatory system. The indication for guided implantology requires a larger opening of the oral cavity, to be maintained for a long time.

d) The exercises currently described take place forcing the mouth against an opposing resistance given by the fist placed under the chin, or stabilization and isometric exercises are recommended, during them an action is exerted against the fingers that push in the opposite direction . The use of a simple compressed spring facilitates the execution of stretching acting in the same manner, contraction opposite to force. Physiotherapy is widely used in the treatment of most rheumatic diseases, including myo-arthropathies. Physiotherapy measures are an integral part of the overall treatment plan. In the presence of contraction of the muscles of the temporomandibular joint system and detection of the relationship between the dental arches (bite mio-centric, skull mandibular relationship, etc.) allows the possibility to relax the muscles. This allows a better assessment of the masticatory system (including the possibility of increasing the spaces between the arches) and an easier detection of the intermaxillary relationship, regardless of the technique chosen. Relax muscles and increase the opening of the mouth allow to apply with greater ease the technique chosen, classical gnathology, Planas technique, Alonso, Jankelson, etc..

e) The scientific literature does not recommended to provide the patient with an exercise program complicated and/or requiring too much time to be performed, because there is the risk that the patient gets tired and does not perform as specified. One or two exercise are referred to as the optimal choice. The course of physiotherapy with the "oral dynamic stretching" allows to simplify the execution of physiotherapy exercises.

f) It useful in surgery of the temporomandibular joint.

g) The stretching movements are particularly effective when the muscle is previously contracted (post-isometric stretching). Contraction-relaxation stretching or contraction-relaxation-contraction of the agonist muscle called Proprioceptive Neuromuscular Facilitation (PNF) is more effective than other types of stretching (e.g. static). The muscle is stretched and, at the same time, is contracted for 6/8 sec. to 50 - 100% of the maximum value. The contraction is followed by a new stretching phase. This method is easily applicable with the device called "dynamic oral stretching."

h) All therapies assessed have result in an improvement in symptoms of chronic musculoskeletal pain or quality of patient's life for the duration of the treatment period: the patient, then, gets a benefit by most physiotherapy measures; i)

i) increasing the number of therapy sessions more satisfactory results are obtained;

j) patients derive greater benefit if subject to any physiotherapy treatment than otherwise.

k) All therapeutic modalities produce their beneficial effect through a multiple action mechanism which reduces fear, depression and anxiety By diverting attention away from the pain, the latter decreases in intensity. Having to use a stretching spring "distracts" the patient, helping to reduce the intensity of pain.

The "TheraBite" a similar device with the same indications

The web-site http://www.atosmedical.com/Corporate/Focus_areas/Mouth_and_Jaw/The_TheraBite_System.aspx says:

The TheraBite ® Jaw Motion Rehabilitation System™ is a portable system specifically designed to treat Trismus and mandibular hypomobility. The system uses a repetitive passive motion and stretching for an effective jaw rehabilitation therapy useful to:

Restore the mobility and flexibility of the muscles of the jaw, joints, and connective tissues, thereby increasing the opening of the jaw, this mobilization is crucial in reducing inflammation and pain. The mouth opening may be limited by internal factors, for example, bony ankylosis, arthritis, infection, trauma; a scar in the fibrous tissue can cause stiffening of joints and muscles and requires stretching for re-lengthening the collagen fibres. Probably also a micro-trauma may involve bruxism..

· It relieves muscle pain (myofascial), usually caused by abnormal inflammation that exerts pressure on nerves, muscles and bones. This inflammatory process can be corrected througha range of passive movement exercises.

· Mandibular Trismus; is a debilitating condition that can affect people of all ages. If not properly and promptly treated, the condition can worsen and have a negative impact on quality of life.

· After surgery and maxillary radiation; the joints that have been immobilized may undergo degenerative changes within a few days.

· Disorders of the temporomandibular joint (TMJ);

· TMJ trauma.

· helps to increase mass and strength in hypotonic muscles;

·reduce anxiety in patients, allowing them to control muscle function.

· strengthen the weakened muscles of the jaw.

Within the site the mechanisms that lead to trismus are deepened and several related physiopathogenetic mechanism are discussed.

The trismus can result from muscle, articular damage, rapid growth of connective tissue (scars), or a combination of these factors.
alterations of the central nervous system, trigeminal injury, drug and medication toxicity may also limit the opening of the mouth.
The mandibular trismus may occur as a result of:

· Third molar extraction

· hyperextension

· hematoma resulting from injection of the dentist,

· as delayed effect of fixation after mandibular fracture or other trauma.

· Radiation therapy to the head and neck.

· Surgery of the head and neck

· TMJ Disorders

· Infections

· Systemic diseases, such as rheumatoid arthritis or scleroderma

· direct trauma to the head and neck;

· Indirect trauma, for example, whiplash

· Burns of the face

· Stress due to disorders, for example, bruxism.

· Congenital (at birth)

· because of hereditary diseases

· because of ageing

Regardless of the immediate cause, Trismus (mandibular hypomobility) will ultimately result in degeneration of the muscles and joints. Studies have shown that muscles that are not able to pass through their range of motion for no longer than 3 days begins to show signs of atrophy.

Similarly, the joints that are immobilized quickly begin to show degenerative changes, such as thickening of the synovial fluid and the thinning of the cartilage.

When patients receive radiation treatment in the head and neck, Trismus may also progress slowly and unnoticed for months, causing minor changes in muscles and joints.

Therefore, the treatment, consisting in a gentle passive movement, should begin as soon as possible.

In the Instruction Manual attached the following indications are described:

The TheraBite system helps to achieve:

1.Correct opening of the jaw: by stretching the connective tissue mobilizing the joints stretching the muscles completely.

2.Relieve of pain and inflammation.

3.passive mobilization of join. Researches have highlighted the beneficial effects of mobilization in the management of joint disorders. The movement is necessary to prevent the degeneration of the cartilage, the tissue layer that covers most of the articular surfaces.

4. In many cases it can stimulate healing of the joint and reduce pain and swelling.

5. Stretching and relaxing muscles, gradual mobilization exercises can help patients suffering from muscle pain to improve movement.

6.Passive movement may also offer therapeutic advantages, especially in the post-operative period.

This rehabilitation exercise of the jaw is effective when carried out every day. It allows to be used wherever the patient is.

The TheraBite system has been used successfully by thousands of individuals suffering from Trismus.

In countries like the United States (Medicare) and Germany, the TheraBite system is approved for reimbursement by the insurance company. This rule varies from state to state and from country to country.

A disposable scale used to measure the range of motion in scale allows patients and their doctors to measure the exact mandibular opening, monitoring progress.

A graph allows to assess the measurement of the patient's progress and allows users and their doctors to monitor progress through a visual feedback ....

The aid assists the patient to maintain constant the static opening and the force applied during stretching.

It is preferable that the therapy with TheraBite is monitored by health care professionals.

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