Amy Jewel

  Amy Jewel The successful practice of maxillofacial orthopedics and orthodontics demands that the doctor keeps his or her mind open to the constant advances being made in our understanding the underlying causes of a patient’s malocclusion. The following case presentation will provide the reader with the opportunity to evaluate a patient suffering from air way obstruction and improper tongue function, which in turn have caused under developed dental arches, a skeletal Class II, T.M.D., and a severely underdeveloped mid face.

We would like to point out at the outset of this presentation that the patient was post pubertal, a female 27.4 years of age. Her treatment contradicts many of the classic concepts held by the formal orthodontic community regarding skeletal remodeling that can be attained for this aged patient. We would also like to draw the reader’s attention to the treatment time of 18 months, and the major changes that occurred to the patient’s facial relationships.

The patient presented as a 27.4 year old female requesting a second opinion for her orthodontic therapy. She had been presented with a treatment plan that included a transverse maxillary osteotomy, four first bicuspid extractions, and a mandibular osteotomy to correct the skeletal Class II and open bite.

Records were made at the initial appointment that included a lateral skull radiograph, a panoramic radiograph, six trans-cranial radiographs, and impressions for orthodontic study models. A complete clinical examination was performed as well. The patient’s malocclusion was diagnosed with the following five components.

The Myofunctional Component:

The patient had an anterior tongue thrust also known as an infantile swallowing pattern. Most patients acquire this pathologic habit at birth as a result of improper body position when nursing. The infant is forced to swallow with the Facial nerve using the muscles of facial expression, as opposed to swallowing with the Trigeminal nerve using the muscles of mastication. This abnormal adaptation allows the infant to swallow prone without aspirating the milk when nursing.

Most children revert back to a normal swallowing pattern using the Trigeminal nerve once they begin to crawl and their body position becomes more upright. However some children do not make this spontaneous adjustment and continue to swallow with the Facial nerve as seen in this patient.

The anterior tongue thrust has two major negative effects on the patient’s growth. First, the lack of correct pressure of the tongue against the maxilla causes underdevelopment of the maxillary arch and the upper mid-face. This can easily be seen in the starting occlusal views of the patient and her upper study cast.

Fig 1. 

Fig 2.

The second negative effect of an anterior tongue thrust on facial growth is the creation of a skeletal Class II and open bite malocclusion. These effects can be seen in the patient’s starting profile photograph (Fig.#3 ), and in her pre treatment Bimler Elite and the Delaire cephalometric analysis (Fig.#4 ).

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Fig 4.

Part of this patient’s comprehensive therapy included retraining the swallowing pattern to recruit the Trigeminal nerve and the muscles of mastication. Failure to correct this component of the malocclusion would have resulted in severe post treatment relapse.

The Respiratory Component:

 The underdeveloped maxilla and the trapped skeletal Class II mandible reduced the nasal and oral pharyngeal airways forcing the patient to breathe through her mouth as opposed to through her nose (Fig.#5.) Proper nasal respiration is critical for a number of reasons:

  • Mouth breathing exacerbates the development of a skeletal Class II, open bite malocclusion. The constant open position of the mandible results in excess lower facial volume (The lower basic angle, Bimler), and excess posterior facial height (alveolar height, Bimler).
  • Mouth breathing reduces the oxygen saturation level in the blood stream by up to 40%. This occurs as a result of the loss of the following benefits of nasal respiration:
  • Nasal breathing allows air to pass over the turbinates which places it into a vortex as it enters the lungs. This in turn allows the lungs to extract up to 40% more oxygen from the air.
  • Nasal breathing allows the body to produce Nitrous oxide as the air passes through the nose. This is converted into Nitric acid which facilitates a more effective uptake of oxygen from the lungs, and a more effective release of oxygen into the bloodstream for the oxygen to bond onto the Hb.
  • Nasal breathing allows a low level of carbon dioxide to be retained in the lungs. We need 6.5% residual volume of CO2 in the lungs to acidify the blood pH of 7.45 to a pH of 7.35 to release O2 from the Hb. This is known as the “Bohr effect”. On the other hand mouth breathing flushes out CO2 from the lungs and in turn reduces the oxygen saturation level of the bloodstream.
  • Nasal breathing as opposed to mouth breathing brings the air temperature reaching the lungs to body temperature. This allows the lungs to extract oxygen more efficiently.
  • Mouth breathing prevents the nasal respiratory system from protecting the patient against air borne infections. This occurs for two reasons:

a.) The cilia that line the nasal passages act as filters to remove dangerous particles from the inhaled air.

b.) The nasal turbinates are lined with lysosomes which excrete antibacterial enzymes which in turn help to prevent harmful organisms from entering the respiratory system.

As a result of mouth breathing the child does not develop correctly, and we do not function well as adults. It is very difficult to find any reference to treating these important problems in the formal orthodontic literature, and they obviously play a vital role in the long term health of the patient regardless of their dental relationship.

The Under Developed Mid-Face Component:

The under developed mid-face is associated with incorrect tongue function and upper respiratory obstruction. Mid face incompetence causes not only constriction of the nasal air way, but also congestion of the Ethmoid sinuses. This congestion prevents the veins beneath the orbits from properly draining the venal blood flow causing “dark areas around the eyes”, known as venal congestion or venal pooling. This can easily be seen in the patient’s starting facial photographs (Fig. #6 & Fig.#7 ). Note the changes that have occurred as a result of developing the patient’s upper mid-face, (Fig.# 8).

Fig 6. 

Fig 7. 

Fig 8.

Upper mid-face underdevelopment also effects the shape of the skeletal orbits. This in turn causes the ocular mass to become more ovoid which results in a change of vision for the patient. Notice the dramatic remodeling that has occurred in the patient’s skeletal orbits following the development of her upper mid-face. Her vision significantly improved with the development of her upper mid-face.

The under development of the upper mid face also causes constriction of the nasal pharyngeal air way. This in turn results in reduced air flow through the nose and contributes to the patient being forced to breathe through the mouth.

The Auditory Component:

The patient reported a history of ear infections as a child, and tinnitus with conductive hearing loss as an adult. These symptoms are commonly associated with the under development of the maxilla and the trapped skeletal Class II mandible. Both of these skeletal problems reduce the ability of the Eustachian tube to drain the middle ear and placed direct pressure on the Pterygo- tympanic plate. The patient had been examined by two E.N.T. physicians and diagnosed as suffering from Meniere’s disease.

The tinnitus and the reduced hearing self corrected as the maxilla was fully developed and the mandible distracted into the skeletal Class I relationship.

The T.M.D. Component:

The function of both the left and right temporal mandibular joints was evaluated. This evaluation included six trans cranial radiographs (Fig.#9 ), and a range of motion study. The patient reported a “clicking” noise in both joints on opening. Both joints were diagnosed as being self reducing anterior displacement of the disks with no lateral displacement present. This type of internal derangement is classified as a SR Type II, and does not require a demand position healing splint. The self reducing Type II internal derangement can be treated by correctly placing the mandibular condyle on the disk and stabilizing the occlusion at this new position.

Fig 9.

The patient’s T.M.D. was caused by an underdevelopment of the maxilla which had trapped the mandible, and was exacerbated by the anterior tongue thrust. Both mandibular condyles were posteriorly displaced perforating the posterior attachment, and bearing against the Pterygo-Tympanic plate. The pressure against the plate was a contributing factor to the patient’s tinnitus, vertigo, and conductive hearing loss. The patient had sought medical attention for these symptoms, and had been miss diagnosed as suffering from Meniere’s disease.

It should be noted that the function of both Temporalmandibular joints returned to normal following therapy, and that the symptoms of the Meniere’s disease totally subsided.

The Orthodontic Component:

The patient presented with an Angles Class II dental relationship that had previously been diagnosed as maxillary arch length loss with a dental protrusion. The Bimler Elite and deLaire cephalometric analysis showed the patient to be a skeletal Class II with a retrognathic mandible, and the over jet of 10mm to be the result of a mandibular retrusion as opposed to a dental and maxillary protrusion (Fig.#10 ).

Fig 10.

The severe upper dental crowding was caused by the underdeveloped maxilla and not by maxillary arch length loss as previously diagnosed. Note the attrition on the upper and lower first and second molars. This was the result of parafunction caused by the T.M.D. component of the malocclusion (Fig.#11).

Fig 11.

Notice the parafunction and attrition were greater on the patient’s right side. The long term response to parafunction is exostosis at the insertion of the muscle involved. This can be seen in the size of the lingual tori and the gonial notching both being greater on the patient’s right side (Fig.#12 & Fig.#13). This is the reason many TMD patients also suffer from Coronoid hyperplasia, Eagles Syndrome, and Earnest Syndrome.

 

Fig 12. 

Fig 13.

The Treatment plan: The first phase of the treatment was to develop the maxilla with an Advanced Light wire Functional appliance (A.L.F.), in conjunction with standard orthodontic therapy to level, align, and torque the maxillary dentition using multi gradient force martinsitic arch wires (Fig.#14). The patient wore a flat plane “suck down” splint on the lower arch which she ate in and removed only for hygiene (Fig.#15 & Fig.#16). She also began her myofunctional training program to learn how to swallow with the Trigeminal nerve as opposed to the Facial nerve. The midline omega loop of the maxillary A.L.F. appliance was initially activated with a 3mm transverse load, and this load was maintained throughout the treatment. The omega loops mesial to the maxillary first molars were not activated allowing them to function as “shock absorbers”. This in turn allows the A.L.F. appliance to produce a bio-compatible force that will correspond with the natural cranial rhythm of the patient.

Fig. 14 

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Fig 16.

The maxillary sutures were released at each four week adjustment appointment in accordance with the Nordstrom protocol for cranial movement (Fig.#17, Fig.#18 & Fig.#19#. Notice the amount of skeletal development that was obtained within the maxilla and the alveolar process in the first 12 months of treatment (Fig.#20 ). Also notice the dental alignment on the Roman arch form with no dental “tipping”. The second phase of treatment involved full fixed orthodontic appliances being placed on the lower arch. Vertical elastics, 1/8”, 4 1/2oz, were employed from the upper cuspid to the lower cuspid. These elastics had two effects (Fig.#21).

 

Fig 17.

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Fig 20.

 

Fig 21.

• They begin to close the anterior open bite by erupting the anterior dental segments.

• They begin to pivot the mandibular condyles back in to their correct relationship on the articular disks.

Once the posterior mandibular teeth were leveled, aligned, and torqued, a vinyl bite closing splint was placed on the lower arch (Fig.#22 ). The patient ate in this splint and continued the vertical elastics until both articular disks were fully reduced, and the anterior open bite closed. Retention was obtained using standard upper and lower Hawley retainers during the day, and a night Garcia retainer to protect the Temporalmandibular joints when the patient was sleeping (Fig.#23). The total active treatment time was 18 months.

 Fig 22.

 

Fig 23

The Results of Treatment:

The patient was able to attain both a dental and a skeletal Class I balanced occlusion (Fig.#24, Fig.#25). This was confirmed by both the Bimler Elite and the Delaire cephalometric analysis. The patient was able to retrain her swallowing pattern to correctly use the Trigeminal nerve. The patient was able to properly breathe through her nose, and all of her related respiratory dysfunctions returned to normal. All of the associated symptoms of the patient’s T.M.D. were eliminated including those of Meniere’s disease. The changes in the patient’s facial esthetics are self evident, (Fig.#26 ).

 Fig 24.

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Fig 26

Conclusions:

This case is a classic example as to how we as dental professionals are educated to view our patients and their malocclusions. The critical issues involved are not a particular appliance technique nor a treatment philosophy, but rather our ability to fully understand all of the ramifications of a complex malocclusion. We as health providers have a choice of being dental physicians, or simply being dental mechanics when we treat our patients. It is our hope that this case study has provided the reader with the ability to help better understand the options that are available when treating an orthodontic patient.

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