First Molar Extractions in a Patient with Marfan Syndrome

Maxillofacial conditions associated with MFS include dolichocephalism, enophthalmos, downward-slanting palpebral fissures, maxillary constriction, maxillary retrognathism, and mandibular retrognathia.² A high-arched palate is a minor diagnostic criterion. Some 70% of patients with MFS are referred for orthodontic treatment.³ Intraorally, such patients commonly present with long, narrow teeth; a severe positive overjet; posterior crossbite; general malocclusion; and periodontal disease.²

This article describes the orthodontic treatment of a 13-year-old patient with MFS.

Diagnosis and Treatment Plan

A 13-year-old male was referred to the University of Southern California Department of Orthodontics by a general dentist to address an impacted maxillary right canine (Fig. 1A). The patient’s medical history included Marfan syndrome, cardiac surgery to repair a mitral valve, asthma, and difficulty concentrating at school.

Clinical findings included facies consistent with mouthbreathing, a convex profile, dolichocephaly with excessive lower facial height, and lip incompetence. The mandible was shifted to the left, and the maxillary midline was shifted to the right of the facial midline. The patient exhibited incisal edge and gingival margin inconsonance and insufficient incisor display in smiling.

Intraoral examination found a maxillary transverse deficiency without crossbite, due to the increased curve of Wilson. The maxillary right and left first molars were in a Brodie bite. The first molar was a half-step (3.5mm) Class II, but the canine classification could not be determined because of an ectopic maxillary left canine and an impacted maxillary right canine. The maxilla presented with a high vault and a “V” shape, with 12mm of crowding; the mandible had an 8mm arch-length shortage.

Periodontal probing revealed generalized plaque and bleeding on probing, as well as pockets as deep as 6mm at the maxillary first molars. Cone-beam computed tomography showed a palatally impacted maxillary right canine, along with root resorption and morphological anomalies in all first molars (Fig. 1B). Vitality testing of the first molars was positive.

Virtual treatment objectives were used to help determine the amount of space required and the optimum mechanics (Fig. 2). Correction of the maxillary and mandibular crowding and achievement of a Class I dental relationship required a total 20mm of space, suggesting the need for maxillary and mandibular extractions.

Three treatment plans were considered, each involving the extraction of all four first molars because of the poor prognosis of those teeth. In the first scenario, orthognathic surgery would allow skeletal and dental correction of the malocclusion, improving the patient’s airway and facial esthetics. In the second scenario, maxillary and mandibular miniscrews would be placed to hold the vertical dimension and thus allow skeletal improvement by counterclockwise mandibular rotation and dental correction of the malocclusion. The third scenario was to dentally camouflage the malocclusion by holding vertical growth with a high-pull headgear and maximum maxillary anchorage vs. minimum mandibular anchorage. The patient and family chose the third scenario.

Treatment Progress

The arches were bonded with MBT^* preadjusted appliances, except that the second molars were banded. Leveling and alignment were carried out on .016" nickel titanium archwires, followed by .016" × .022" nickel titanium. A high-pull headgear was worn for a minimum 12 hours per day to control maxillary vertical growth and to provide anteroposterior anchorage throughout treatment. Once the arches were leveled, heat-treated .016" × .022" stainless steel archwires with posts soldered distal to the lateral incisors were placed, and space closure was achieved using active tiebacks to the soldered hooks.

Space for the maxillary right canine was opened using an open-coil spring on an .016" × .022" stainless steel archwire. Once the space was opened, the canine started erupting palatally without the need of for surgical exposure. The canine was brought into the arch using an .014" nickel titanium overlay and a power chain from the .016" × .022" archwire to a bonded lingual button (Fig. 3).

The post-treatment panoramic radiograph showed root parallelism and no obvious root resorption. Assessment of cephalometric measurements demonstrated that the vertical growth was maintained, as indicated by the improvement in the profile and soft tissue (Table 1). Incisor inclinations were within the normal range.

Discussion

Because MFS patients often have cardiovascular disease, the risk of endocarditis during invasive dental treatment must be considered.⁴ Following American Heart Association guidelines, no antibiotic prophylaxis was needed prior to orthodontic treatment in the present case.⁵

Craniofacial patterns frequently associated with MFS include dolichocephaly, retrognathia, a long face, and a high and narrow palatal arch,¹ as were observed in our case. This patient also presented with a short ramal height, an obtuse gonial angle, and a steep mandibular plane. According to De Coster and colleagues, the growth of sutures in the cranial base of patients with MFS reduces their growth potential, and the anterior facial height in MFS patients is significantly greater than normal.²

Additionally, patients with MFS exhibit abnormalities in their periodontal ligaments and root morphology. Because the periodontal reaction to tooth movement is altered in MFS cases, this should be taken into account when moving teeth orthodontically.⁶

Developmental abnormalities of the teeth in MFS patients may include supernumerary teeth, enamel defects, dentinogenesis imperfecta, tooth dysplasia, and cyst formation in the jaws.³ Radicular deformations and pulp obliterations are other common findings. In the present case, radicular deformations associated with periodontal defects were found in all four first molars. Because of the crowding and poor prognosis for these teeth, we decided to extract them.

Angle described the first permanent molar (FPM) as the keystone of the dental arch. The importance of this tooth is derived from its crucial role in maintaining normal masticatory function and dentofacial harmony.⁷ Therefore, many orthodontists prefer to avoid extraction of FPMs whenever possible. If the patient exhibits a brachyfacial type, deep bite, missing permanent teeth, arch spacing, or Class III malocclusion, then FPM extraction is contraindicated.⁸ Conversely, if a patient has a Class I occlusion with crowding, no missing permanent teeth, and FPMs with a poor prognosis, the extraction of FPMs should be considered at the optimal time—generally between 9 and 11 years of age.⁹ Since our patient presented with crowding, no missing permanent teeth, and FPMs with a poor prognosis, we elected to extract the first molars.

Normando and Cavacami described the effects of bilateral FPM extractions on the skeleton: a reduction in the Gn-SNA angle, counterclockwise rotation of the occlusal plane, and a mild decrease in lower anterior facial height.¹⁰ In our case, because the patient had a long face and high-angle tendency, these side effects were considered favorable.