(Le Gall et al 2010, Le Gall et Lauret 2011, Le Gall 2013)
Note: If a double clic on the video is done, it will appear in full screen
Fig. B6a,b: Two videos showing the procedure to detect prematurity, by using the dual protocol: jig and tongue.
Fig. B7a,b,c: The jig is made in Revotek® material, from GC. The polymerisation begin by the occlusal face, and then the external surfaces. During polymerisation of the internal surfaces, the jig must be very slightly deformed between two fingers, so that later, the jig can remain in place, without falling down.
Fig. B10a : adaptive occlusion Fig. B10b : An anterior deprogramming device is worn from 1 to 4 minutes, with one median opposite contact and without any pressure. It allows to cancel adaptive engrams and tensing muscles to relax Fig. B10c : Then the patient close directly on the prematurity. The jig must be put back instantly, to avoid the reactivation of avoiding engrams.
During the occlusal analysis, conducted on the armchair to MIO test, the patient must be placed in a suitable posture to swallow food. Standing up, seated, or very slightly leaning back, carrying her head naturally, with no lateral rotation, avoiding to lie on the back (supine), where it is harder to swallow (at night, swallowing saliva in this position is often realized with no dental contacts). Nevertheless, if the patient is placed in a semi-stretched out position, with her head, non tilted back, and maintained in the axis of the body, with her tongue in contact with the palate anterior. Wearing during 1 to 5 minutes with no interdental pressure, this anterior deprogrammer with a single median antagonist contact, allows muscles to relax and to deprogram previous closure pathway from memory, by deleting others MIO contacts. At the same time, the firm positioning of the tip of the tongue against the median retro-incisive palatal region, associated with a few swallowing exercises, allows to put the mandible, the tongue muscles and the oropharynx in a swallowing situation. The optimal positioning can be obtained, step by step, by repeating the following award at the patient: “place the top of your tongue in the middle, in contact with the palate…tip on front… firmly placed against the palatal papillae, just behind the upper incisors”.
When muscles are relaxed, the tip of the tongue is held against the anterior portion of the palate, during the removal of the jig, with half-open mouth. The patient must then slowly raise her mandible, with no muscular pressure, up to the first contact and indicate his position with a a finger. Carried out a second time, the procedure must confirm the first indication. A potential malocclusion can be objectified then, by the same procedure, by placing between both lateral sectors simultaneously, strips of very thin marker paper (15-20μm).
Fig. B10d: Rules Correction for a cuspal interference on the closure path. The support points must be preserved. The correction is made on the sliding surface toward the MIO. In case of extrusion/intrusion, it must be corrected first, according to the curves of Spee and Wilson. The opposite teeth must be restored also, in accordance to the curves. Don’t forget that a subcontract can also be deflector for the mandible.
If there are multiple, simultaneous and harmonious contacts, the position is in swallowing neuromuscular balancing. The reset of the memory of closure has been done in the same occlusal position.
If at this stage, the tip of the tongue is turned over against the posterior part of the palate (Fig B4), the mandible comes back in a position CR, and during closure, there must be a symmetric sliding towards MIO.There are not interferences, but there are anti backward slopes, that delimit the posterior envelope of chewing cycles while protecting TMJ (Le Gall and Lauret, 2011).
If the sliding movement is not symmetric, retouch is ‘a priori‘ banned. These slopes are the transverse posterior limit of the guidance of cycles, on the posterior teeth.
When chewing is simulated and adjusted on the two side (generally by addition), a new backward movement test,can be done in the sagittal plane. It allow for assess whether both sides are in symmetric balance or not,and whether a correction possible, by addition of the sliding slope in under-guidance, must be performed.
When swallowing occlusion is adjusted and balanced, the use of a jig is no longer necessary, nevertheless placing the tongue in an anterior, high and centered position remains necessary, for later tests of closure.
If there is only one point of contact, the occlusal analysis of the neighboring teeth will allow to determine, whether, on this tooth, there is a excessive and/or deflector contact, or whether a lack of contacts, in is reponsible, during closure on the nearby teeth. After each test of closure, the jig must be immediately replaced on the incisors with an opposite point of contact, with the tongue touching the palate, to prevent the patient’s reprogramming in its previous closing memory.
When one or several corrections are done (addition/subtraction), closing the test should show well balanced contacts, of the same intensity and well distributed over a maximum of teeth (MIO)
When in doubt, intermaxilla relationship of deglutition must be recorded and the models mounted on a conventional articulator for a preparatory analysis and simulation of balancing, before any alteration, in the mouth.
Note 1: If an imbalance of the body posture is suspected, It’s suggested to check first the closure path, with the patient seated or in a slightly reclined position, with the general postural component ineffective, and secondly standing up with a reactivated postural component. If the occlusal contacts are different, there is probably a general postural imbalance, which interferes with the posture of the mandible. In this case, after balancing the patient in a semi-stretched position or seated one , he must adressed to a posturologist and after treatment of the postural problem, the closure path must be checked again immediately.
Note 2: This protocol can be applied to additional uses: to record the intermaxillae relationship for occlusal analysis on articulator and for prosthetic realizations
If vertical dimension is lost, the protocol jig+ tongue position, with several deglutitions and associated to phonetic tests (similar to those of complete dentures), allow to find again the vertical dimension and to record it.
Vertical dimension is a variable located in a custom normality range. Changes in vertical dimension of less than 5 mm are generally well supported by the neuro-muscular tract (Moreno and Okeson 2013). Personally, in toothed subjects, we limit the change of VD to a slightly lower value at the height of the free space of rest, so as not to disrupt the neuromuscular equilibrium. If the increase of VD is insufficient, a second increase is realized a few weeks later, when a new free space of rest will be recreated.
Summary: Protocol of use of the modified jig and tongue positioning,
- wear 1 to 5 minutes, in average 3 minutes
- one single non deflectory, median, anterior and antagonist contact
- wear with no pressure,
- tip of the tongue held against the anterior portion of the palate,
- a few swallowing,
- then jig is removed with half-open mouth and the patient slowly raises her mandible until the first contact. He:she indicates the position with a finger. Performed a second time, procedure must produce the same result. Marker paper can then be placed to mark first contact.
-a- -b- -c- -d-
Fig. B10e: (a) Clinical case showing the correction of a cycle-in underguiding, upon insertion of the restoration of the right maxillary first molar. After correction, the molar cycle-in guides, are balanced with that of the mesial palatal side of the first bicuspid. (B) Other cases. The 2 cycle-in guides of the first premolar are the only assets. Those of the second bicuspid and molar are under-guiding and must be restored by addition. The cycles-outs, are balanced. (c) General figure of these clinical situations. Read below. (d) Checking of the closure path, using an anterior jig and tongue. The posterior deflector contact must be deleted by subtraction preserving MIO support, before the adjustment of mastication.
Note 3 : Checking chewing functional surfaces simultaneously with the analysis of the closure path is often necessary. The mesio-palatal side of the first upper bicuspids often appear a early contact,considered a prematurity on the closure path. Before any alteration, check that it’s not a cycle-in guide, on the same side, balanced or not, with posterior teeth cycle-in guides. Or in the case of cycles, in frontal orientation, as in Class II division 2 Angle, that it is not a cycle-in guide, balanced with contralateral side. These guides are physiological. They participate in the protection of the TM joint structures, with other cycle-in guides and they maintain the functional interplay, posterior to MIO, necessary to do cycle-in on the same side. When checking the posterior functional play in the sagittal plane, with the tip of the tongue turned, toward the back of the palate, it may appear an asymmetry when sliding forward after. Before subtracting on the side that appear over-guiding, be sure that the other side is not under-guiding and requires an adjunction.
- Le Gall M. G. Physiologic balancing of Occlusion Part one.: How can swallowing occlusion be adjusted? Rev. Odont. Stomat. Sept. 2013; 42:198-210 (English and French published article)
- Le Gall M. G. Physiologic balancing of Occlusion Part two : How to adjust posterior occlusal faces?. Rev. Odont. Stomat. Nov. 2013; 42: 243-257 (English and French published article)
- Le Gall M. G., Lauret J. F. (†). Book : 3rd edition enriched, 2011 “The occlusal function: clinical implications“ (French edition only) Editions CDP.2011 Paris www.editionscdp.fr/
- Le Gall M.G., Joerger R, Bonnet B. Où et comment situer l’occlusion des patients ? Relation centrée ou position de déglutition guidée par la langue ? Cah. Prothèse 2010; juin 150: 33-46
- Le Guern J.Y. Etude expérimentale de la répétitivité des contacts occlusaux sur le chemin de fermeture lors de l’élévation mandibulaire. Intérêt clinique Thèse Sc. Odontol. 3° Cycle, Nantes, 1987. Cat 1
- Moreno I., Okeson JP Dysfonctionnement de l’Appareil Manducateur et Dimension Verticale d’Occlusion : revue de littérature Réalités Cliniques 2013 vol 24 N°2 p 93-98 (TMJ and Vertical Dimension of Occlusion, literature review)