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Class III

This patient was referred for evaluation and/or correction of a TMJ dysfunction. She is experiencing headaches, neck pain, facial, ear and related dysfunction. She is not able to open her jaw without pain. There is a clicking noise during opening and the mandible has a sigmoid deviation ending in a right deviation movement. The range of motion is 40 to 42 mm with pain.


She has experienced this pain for a number of years, but it is not self-correcting, but is becoming worse with time. She finds that she is not able to work satisfactorily, and the pain is beginning to affect her daily and family life. The quality of her life is not satisfactory and she desires to know if there is something that can be done to improve her situations.She was informed by her regular dentist that a cause-effect might relate to her bite relationship, which was a Class III bite. The dentist referred the patient for evaluation and/or treatment as he was not comfortable treating this degree of difficulty. He had referred the patient for another opinion. That specialist’s opinion consisted of surgery to correct the malocclusion.


Three primary components must relate harmoniously for the oral structures to remain stable. This involves the joint structures, the muscles of mastication and the occlusal bite relationships. This patient suffers from a dysfunction of these three oral components. The temporomandibular joints are not functioning within the major portions of the functional envelope of motion, but are posterior- peripherally oriented. The primary and secondary muscles of mastication are found to have multiple trigger points. The occlusal relationship is not a stable class I association, but rather tends towards a class III relationship.As a result of the compromises in the relationship of these three entities, the patient is suffering from recurrent muscle and joint related pains. She has almost daily pain that is increasing in nature. She finds she is not able to enjoy her life as she had before and is desirous to ascertain if assistance can be found. A diagnostic phase of evaluation is recommended to determine the extent and magnitude the imbalance in the oral structures is related to the pain she experiences.


The patient experiences a complete remission of TMJ signs and symptoms with the intraoral diagnostic orthotic. She no longer has any of the headaches, neck pain, facial, or TMJ pain while she wears the intraoral diagnostic orthotic or splint. The muscles of mastication are able to function without pain, although chronic trigger points still remain.When the appliance is removed for any significant period of time the pain begins to return. The intraoral orthotic enables the practitioner to alter the patient’s bite relationship and then ascertain the effects this has on the patient’s TMJ signs and symptoms. Because this is a reversible diagnostic phase, it is possible for the patient to function in this relationship for some time to ensure the results will remain stable. Removal of the appliance with a return of pain, followed by reinserting the appliance and the pain goes away further documents the structural and functional relationships.

Treatments must be found that will enable the approximation of the dentition to support this postural relationship of the mandible to the maxilla. Orthognathic surgery would be able to approximate the dentition, but at the expense of management of the mandibular relationship to the maxilla. Therefore, non-surgical options are recommended and orthognathic surgery is retained as the last option if all else fails.


The patient’s functional mandibular – maxillary relationship is a full class III relationship. After this functional position is determined, the arches must be developed to enable an approximation of the dentition to support the function TMJ relationship. The maxillary arch development is initiated while the diagnostic appliance serves to maintain the mandible in a functional relationship with the maxilla. This necessitates frequent adjustments of the orthotic to allow the dental movements while maintaining the mandibular – maxillary relationship.The orthotic is converted from a disc appliance to a muscle deprogrammer in the region where the desired dental movements are to be accomplished. The orthotic is retained as a disc appliance in those regions where dental movements are not desired. In some instances, troughs are made in the occlusal acrylic disc appliance regions to allow teeth to be moved in one direction, but impeded from movement in a different direction. The ULAW system or the TAW-crozat can also be used to assist in the arch development.


A ULAW system along with hooks for a reverse face mask were made for this adult patient. Advancement of the maxilla was attempted with this combination while the orthotic maintained the mandibular-maxillary relationship. The orthotic required significant adjustments and this form of therapy proved to be only partially successful for this adult patient.


The reverse facemask could only be worn part time by the patient. A number of interrelated problems become evident. Most important was the force applied by the face mask against the mandible, resulting in a distal force on the mandibular condyles within the glenoid fossa. This proved to be somewhat painful for the patient. She was also unable to wear the appliance for more than a few hours each day due to the requirements from her work and family. This treatment also required significant adjustments to the mandibular appliance. To overcome this aspect, the ULAW was converted into a repositioning orthotic with posterior molar pads to maintain the mandibular maxillary relationship.


The maxilla did not advance a sufficient amount to enable the approximation of the teeth so support the functional mandibular – maxillary relationship. The anteriors were approximated to only an edge to edge relationship without the ability to satisfactorily complete the treatment.


These pictures demonstrate the full Class III relationship that remained after this attempted treatment. Orthognathic surgery was considered, but it was rejected due to the inability to control the mandibular – maxillary, TMJ relationships. Further corrections would require the removal of a mandibular bicuspid on each side.


Mandibular first bicuspids were extracted and the posterior molars were brought into full contact. The ULAW with the anterior acrylic was used to help maintain the physiological mandibular – maxillary relationship during these corrections and the remaining posterior teeth were approximated.A mandibular lip bumper was constructed with tubing placed over the anterior buccal wire with coiled springs to help move the mandibular cuspids distal. Power chain elastics were used to facilitate the distal movement of the mandibular cuspids, but care was taken to control the mesial movement of the mandibular posterior teeth.


Class III elastics were used to assist in the distal movement of the mandibular cuspids. Extreme care must be used with Class III elastics for patients suffering with TMJ dysfunction. Extremely light elastics were intermittently used in conjunction with the lip bumper and power chains to control the movement of the mandibular cuspids.


The mandibular cuspids were positioned in the proper relationship to provide the proper cuspid guidance with the maxillary cuspids. The mandibular anteriors were bracketed and were moved distal with power chains. The Class III elastics were used as anchorage mechanics to keep the cuspids from being moved more to the mesial. Class III elastics that are used as anchorage mechanics require only part time wear, versus full time wear if the elastics are used as the power mechanics.


A slight forced pivot mechanism is evident with the vertical elastics as the final space closure in completed. The vertical elastics cause the mandible to be slightly rotated about the posterior teeth, resulting in a slight decompression within the temporomandibular joints.


These pictures demonstrate the bite relationship evident at the debracketing appointment. No retainers were fabricated as the patient’s occlusion is in harmony with the functional joint position with minimal muscle activity. The patient is free of TMJ signs and symptoms.


These pictures demonstrate the bite relationship at the beginning of treatment on the left and the bite relationship at the end of treatment on the right. The patient has been free of TMJ signs and symptoms since the usage of the diagnostic orthotic.


Nine years later the patient is still free of TMJ signs and symptoms. The bite relationship has remained stable, the joint position is within the functional envelope of motion and there has not been any reoccurrence of the muscle pain. No further treatments have been rendered since the debanding and debracketing and there are no anticipated needs for treatments in the future.


Maximal loading is exerted on the dentition with little alterations in the condyle disc fossa relationship as the predominant forces are directed anterior and superior. The posterior bilaminar zone of the disc serves to keep the disc in the proper relationship between the condyle and eminence in normal joint movements.In normal healthy function the teeth and support structures receive the primary loading of the complex and the joint functions properly if the forces exerted by the condyle are directed anterior and superior. This is the normal joint and occlusal associations.

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