The Cleft Palate–Craniofacial Journal 53(2) pp. 253–258 March 2016 Ó Copyright 2016 American Cleft Palate–Craniofacial Association
CASE REPORT Surgical Orthodontic Treatment for Open Bite in Noonan Syndrome Patient: A Case Report Masayoshi Kawakami, D.D.S., Ph.D., Kazuhiko Yamamoto, D.D.S., Ph.D., Tadahiro Shimomura, D.D.S., Tadaaki Kirita, D.D.S., D.M.Sc. Noonan syndrome, characterized by short stature, facial anomalies, and congenital heart defects, may also be associated with hematopoietic disorders. Craniofacial anomalies in affected patients include hypertelorism and severe open bite associated with masticatory dysfunction. We treated a Noonan syndrome patient with a skeletal open bite. Surgical orthodontic treatment including two-jaw surgery established a good occlusal relationship after correction of severe anemia. Both upper and lower incisors were moved to upright positions, while clockwise rotation of the palatal plane and decreased mandibular plane angle were accomplished. Lower masticatory activity may affect posttreatment occlusion in such cases. KEY WORDS:
Noonan syndrome, open bite, orthodontic treatment, orthognathic surgery
Noonan syndrome, one of the most frequent dysmorphic syndromes seen in children occurring with a frequency of 1 in 1000 to 2500 newborns, is a multi-organ disease with a broad spectrum of clinical symptoms. The disorder is autosomal dominant, and affected patients are characterized by short stature, facial abnormalities, heart defects, and increased risk of leukemia. A single Ptpn11 mutation evokes all of the major features of Noonan syndrome (Araki et al., 2004). Facial abnormalities include wide-set eyes, broad forehead, a wide nasal base, downward-slanting palpebral fissures, and high arched palate (Sugar et al., 2004; Tartaglia and Gelb, 2005). In addition, mild mental retardation, lymphatic abnormalities, and bleeding problems are variably seen (Singer et al., 1997). A recent report demonstrated effective conservative management of severe open bite and feeding difficulties in Noonan syndrome patients (Fonteles et al., 2013), while a prior case report noted orthognathic surgery in an affected patient that was performed without preoperative or postoperative orthodontic treatment for the occlusal correction (Sugar et al., 2004). Here, we describe a novel case of Noonan syndrome in which orthodontic treatment procedures combined with orthognathic surgery were performed.
CASE REPORT Diagnosis and Etiology A 28-year-old woman with Noonan syndrome was referred to the Department of Oral and Maxillofacial Surgery of Nara Medical University Hospital for orthodontic treatment with a principal concern of masticatory discomfort. She had been diagnosed with Noonan syndrome as a child due to an atrial septal defect and other characteristic findings for which she underwent heart surgery at 8 years of age, then plastic surgery for ptosis at age 15. The patient had a symmetric smile and a Class III molar relationship, along with an anterior open bite from the frontal teeth to premolars. All teeth including the third molars were present. The maxillary midline was 2 mm to the left of the mandibular midline (Fig. 1). A cephalometric examination revealed Class I malocclusion (ANB ¼ 0.48) with a skeletal open bite (FMA ¼ 38.38, gonial angle ¼ 138.28), and both the maxillary and lower incisors showed excessive labial protrusion (Table 1; Fig. 2). A masticatory muscle examination revealed decreased activation of the anterior temporal muscle, while blood findings indicated severe anemia prior to treatment (hemoglobin [Hb] ¼ 5.6 g/dL). Our diagnosis was skeletal open bite associated with Noonan syndrome.
Dr. Kawakami is Assistant Professor, Dr. Yamamoto is Associate Professor, Dr. Shimomura is Research Fellow, and Dr. Kirita is Professor and Chair, Department of Oral and Maxillofacial Surgery, Nara Medical University, Kashihara, Nara, Japan. Submitted June 2014; Revised September 2014; Accepted September 2014. Address correspondence to: Dr. Masayoshi Kawakami, Department of Oral and Maxillofacial Surgery, Nara Medical University, 840 Shijo-cho, Kashihara Nara, 634-8522, Japan. E-mail mkawaka@ naramed-u.ac.jp. DOI: 10.1597/14-196
Treatment Objective and Alternatives The primary objectives of our orthodontic treatment were to close the severe anterior open bite and achieve a Class I molar and canine relationship on both sides, as well as an ideal overjet and overbite. Another objective 253
254
Cleft Palate–Craniofacial Journal, March 2016, Vol. 53 No. 2
FIGURE 1 Pretreatment intraoral photographs.
was to eliminate the abnormal tongue thrust to achieve an unstrained orofacial muscular balance at both rest and during function. One of the treatment options consisted of movement to an upright position and retraction of the anterior teeth to close the open bite using fixed appliances and intermaxillary elastics. However, those alone would not be able to achieve correction of the skeletal open bite. Another plan considered was correction of the open bite and overjet by orofacial myofunctional therapy as previously reported (Fonteles et al., 2013). However, that invasive therapy has limitations for full correction of a severe open bite. Our third option included an orthodontic-surgical approach to correct the open bite, which was chosen by the patient and her parents, because they were primarily concerned about occlusal function. Treatment Plan Orthodontic appliances were used for presurgical alignment including the third molars, and movement of the upper and lower incisors to upright positions, along with extraction of the upper and lower bicuspids. Upward movement of the maxilla was accomplished with a Le Fort I osteotomy, while counterclockwise TABLE 1
rotation of the mandible was done with a sagittal split osteotomy (SSRO). Postsurgical completion of orthodontic leveling was also done. Treatment Progress A preadjusted edgewise appliance (0.018 3 0.025 inches) was placed in both arches, with a 0.016-inch NiTi wire initially used for leveling. Prior to extraction of the upper and lower bicuspids, several laboratory tests were performed, which led us to wait to perform those extractions because of severe iron deficiency anemia (Hb ¼ 5.8 g/dL). Seven months after initial presentation, canal treatment of the upper right first molar was performed for a periapical abscess. One month later, after the anemia had improved (Hb ¼ 10.9 g/dL), all bicuspids were extracted, and retraction of the maxillary and mandibular canines was started. After canine retraction, upper and lower anterior retraction was conducted by closing loops supported by a transpalatal arch between the right and left first molars. The interincisal angle gradually increased over the 2-month period after retraction. The extraction space was then closed, and preoperative treatment was completed with 0.017 3 0.022-inch stainless steel wires.
Cephalometric Analysis Variable
Initial (27 y, 10 m)
Preoperative (30 y, 11 m)
Posttreatment (32 y, 1 m)
Facial angle, deg Mandibular plane (FMA), deg SNA, deg SNB, deg ANB, deg Gonial angle, deg U1 to FH, deg L1 to mandibular plane, deg Overjet, mm Overbite, mm
89.2 38.3 82.1 81.7 0.4 138.2 122.4 98.0 4.0 9.6
88.9 39.8 83.2 82.0 1.2 138.2 115.5 80.0 2.1 5.3
87.3 40.1 85.0 80.7 4.3 134.8 113.5 78.7 4.4 2.6
Kawakami et al., SURGICAL ORTHODONTIC TREATMENT IN NOONAN SYNDROME
FIGURE 2
255
Pretreatment radiographic images. A: Panoramic radiographs. B: Lateral cephalograms. C: Frontal cephalograms.
Next, we planned to perform orthognathic surgery, though waiting was required because of reappearance of anemia (Hb ¼ 6.0 g/dL). That was improved 6 months later (Hb ¼ 12.4 g/dL), then the arches were stabilized with 0.017 3 0.022-inch steel wires with a crimp hock for intraoperative fixation (Fig. 3). After 3 years and 2 months for preoperative orthodontic treatment, orthognathic surgery was undertaken, during which we performed upward movement of the maxillary arch by 5.0 mm using a Le Fort I osteotomy and counterclockwise rotation of the mandible with an SSRO procedure. A horseshoe type osteotomy was also applied for separation of the maxillary bone. Four weeks after surgery, the stabilizing wires were removed and replaced with 0.016-inch Ni-Ti wires in both the upper and lower arches. Then, vertical elastics were worn full-time for 12 months for final positioning of the teeth. The appliances
were removed 11 months after postsurgical orthodontic treatment resumed (age, 32 years 1 month). The patient then used a wraparound type retainer for the upper arch and a spring retainer for the lower arch. Treatment Results The large open bite was closed and occlusion was established with a Class I molar relationship (Fig. 4). Cephalometric superimposition showed a clockwise rotation of the palatal plane and decrease in mandibular plane angle (Table 1; Fig. 5). Both upper and lower incisors were moved to upright positions, which corrected the overbite and overjet (Fig. 6). The patient showed no clinical symptoms of anemia, with the hemoglobin level at 10.2 g/dL.
256
Cleft Palate–Craniofacial Journal, March 2016, Vol. 53 No. 2
FIGURE 3 Intraoral photographs obtained prior to orthognathic surgery.
DISCUSSION Individuals with Noonan syndrome are often complicated with congenital heart disease, with pulmonic stenosis resulting from dysplastic valve leaflets seen as the most frequent manifestation. The present patient had an atrial septal defect and underwent surgery for its repair, with the diagnosis of Noonan syndrome established from preoperative examination findings. Patients with Noonan syndrome have various types of bleeding disorders, though most are reported to be mild (Witt et al., 1988; Singer et al., 1997). Although our patient did not have a bleeding problem, severe anemia was present and we often referred her to the Department of Internal Medicine of our hospital for detailed examinations, which revealed a very low level of hemoglobin. The presence of anemia delayed our decision for tooth extractions and orthognathic surgery. Additionally, she manifested a dry mouth condition that could lead to accumulation of dental calculus and debris, and the reduced salivary secretion made it difficult to control oral hygiene and dental plaque.
FIGURE 4 Posttreatment intraoral photographs.
Our patient had marked mandibular prognathism with an anterior open bite, along with protruding anterior teeth and a Class III molar relationship. An electromyographic examination showed low activities in the masseter, genioglossus, and anterior part of the temporalis, which were considered to be related to the open bite. The skeletal pattern was similar to that in a case reported by Sugar et al. (1994), who used maxillary advancement with a Le Fort I osteotomy without preorthodontic or postorthodontic treatments. On the other hand, we accomplished orthodontic treatment using orthognathic surgery for our patient with Noonan syndrome. Prior to the operation, we moved the upper and lower anterior teeth to upright positions by extraction of the upper and lower bicuspids to establish the postoperative occlusion. One of the craniofacial traits of Noonan syndrome is a high-arched palate with an open bite, while there are also a few descriptions of a narrow high-arched palate in such patients. (Horowitz and Morishima, 1974; Okada et al., 2003; Emral and Akcam, 2009). A high-arched palate with an open bite can be explained by early closure of the cranial
Kawakami et al., SURGICAL ORTHODONTIC TREATMENT IN NOONAN SYNDROME
257
FIGURE 5 A: Posttreatment lateral cephalograms. B: Superimposed lateral cephalometric tracing registered with the S-N plane. Pretreatment, solid line; posttreatment, dotted line. C: Panoramic radiograph.
sutures, which might influence the growth of the dental arch, resulting in a lack of palatal suture growth. A Ptpn11 (i.e., Shp2) mutation occurs in approximately half of Noonan patients, and Ptpn11 mutant mice show craniofacial abnormalities similar to those seen in the syndrome (Araki et al., 2004). The craniofacial characteristics of these mice are a result of reduced skull length and a wider and blunter snout. These characteristics were also observed in the present patient. The open bite in the present case was associated with increased vertical facial angle and the facial height (Fig. 2). For the severe skeletal open bite condition, we performed surgery using a combination of a Le Fort I procedure with a horseshoe osteotomy for the maxilla, which was effective for superior repositioning of the maxillary molar and counterclockwise rotation of the occlusal plane, and decreased the lower facial height with a high-arched palate. Postoperative changes that occur in the maxilla following a combination osteotomy are comparatively stable (Harada
et al., 2002). We confirmed the advantages of that combined surgery and found it useful for reliable superior repositioning of the maxilla, especially in the posterior portion. Furthermore, cephalometric data revealed that the orthodontic/surgical procedures effectively decreased the maxillary and mandibular lengths and the lowered the anterior facial height, while the basal relationship and upright positions of the maxillary and mandibular incisors were also improved. Even though upward movement of the maxilla was performed, there was no decrease in lower anterior face height, which was probably due to the extrusive mechanics utilized, such as up and down elastics for postoperative treatment. The results in this case suggest that low levels of soft tissue and jaw musculature functions have influence on the evolution of open bite. Changes in craniofacial function cause deviations in craniofacial development, resulting in facial skeletal discrepancies and malocclusions (Profitt, 2007). In addition, reduced labial muscle activity may allow
258
Cleft Palate–Craniofacial Journal, March 2016, Vol. 53 No. 2
Therefore, orthodontic treatment and orthognathic surgery are necessary procedures for full correction of severe open bite. Despite the great improvement in occlusion, a compromised occlusal result was achieved in the present case. Normal overbite and overjet are evident, while residual dental space remains in the lower arch. This less than ideal intercuspation may be partially explained by reduced masticatory activities. CONCLUSION Surgical orthodontic treatment with two-jaw surgery provided good results for treatment of a patient with Noonan syndrome with a severe open bite. REFERENCES
FIGURE 6 Regional superimpositions. A: Maxilla tracing registered with palatal plane at Ptm. B: Mandible tracing registered with mandibular plane at Me. Pretreatment, solid line; posttreatment, dotted line.
excessive displacement of the jaws, inducing significant vertical growth and severe protrusion of both the upper and lower incisors. A recent case report showed that myofunctional therapy for severe open bite in a Noonan syndrome patient increased muscle tonus and regained occlusion along with improvement in masticatory ability (Fonteles et al., 2013). However, this approach has intrinsic limitations.
Araki T, Mohi MG, Ismat FA, Bronson RT, Williams IR, Kutok JL, Yamg W, Pao LI, Gilliand DG, Epstein JA, et al. Mouse model of Noonan syndrome reveals cell type- and gene dosage-dependent effects of Ptpn11 mutation. Nature Medicine. 2004;10:849–857. Asokan S, Muthu MS, Rathna PV. Noonan syndrome: a case report. J Indian Soc Pedod Prev Dent. 2007;25:144–147. Emral ME, Akcam MO. Noonan syndrome: a case report. J Oral Sci. 2009;51:301–306. Fonteles CSR, Mota AC, Lima RA, Borges PC, Silveira A. Conservative management of severe open bite and feeding difficulties in patient with Noonan syndrome. Cleft Palate Craniofac J. 2013;50:242–248. Harada K, Sumida E, Enomoto S, Omura K. Post-operative stability of the maxilla treated with Le Fort I and horseshoe osteotomies in bimaxillary surgery. Eur J Orthod. 2002;24:471–476. Horowitz SL, Morishima A. Palatal abnormalities in the syndrome of gonadal dysgenesis and its variants and in Noonan’s syndrome. Oral Surg Oral Med Oral Pathol. 1974;38:839–844. Okada M, Sasaki N, Kaihara Y, Okada R, Amano H, Miura K, Kozai K. Oral findings in Noonan syndrome: report of a case. J Oral Sci. 2003;45:117–121. Profitt WR. The etiology of orthodontic problems. In: Profitt WR, Fields HW, Sarver DM, eds. Contemporary Orthodontics. 4th ed. St. Louis, MO: Mosby Elsevier; 2007:130–161. Singer ST, Hurst D, Addiego JE Jr. Bleeding disorders in Noonan syndrome: three case reports and review of the literature. J Pediatr Hematol Oncol. 1997;19:130–134. Sugar AW, Ezsias A, Bloom AL, Morcos WE. Orthognathic surgery in a patient with Noonan syndrome. J Oral Maxillofac Surg. 1994;52:421–425. Tartaglia M, Gelb BD. Noonan syndrome and related disorders: genetics and pathogenesis. Annu Rev Genomics Hum Genet. 2005;6:45–68. Witt DR, McGillivary BC, Allanson JE, Hughes HE, Hathaway WE, Zipursky A, Hall JG. Bleeding diathesis in Noonan syndrome: a common association. Am J Med Gent. 1988;31:305–317.
CASE REPORT Surgical Orthodontic Treatment for Open Bite in Noonan Syndrome Patient: A Case Report Masayoshi Kawakami, D.D.S., Ph.D., Kazuhiko Yamamoto, D.D.S., Ph.D., Tadahiro Shimomura, D.D.S., Tadaaki Kirita, D.D.S., D.M.Sc. Noonan syndrome, characterized by short stature, facial anomalies, and congenital heart defects, may also be associated with hematopoietic disorders. Craniofacial anomalies in affected patients include hypertelorism and severe open bite associated with masticatory dysfunction. We treated a Noonan syndrome patient with a skeletal open bite. Surgical orthodontic treatment including two-jaw surgery established a good occlusal relationship after correction of severe anemia. Both upper and lower incisors were moved to upright positions, while clockwise rotation of the palatal plane and decreased mandibular plane angle were accomplished. Lower masticatory activity may affect posttreatment occlusion in such cases. KEY WORDS:
Noonan syndrome, open bite, orthodontic treatment, orthognathic surgery
Noonan syndrome, one of the most frequent dysmorphic syndromes seen in children occurring with a frequency of 1 in 1000 to 2500 newborns, is a multi-organ disease with a broad spectrum of clinical symptoms. The disorder is autosomal dominant, and affected patients are characterized by short stature, facial abnormalities, heart defects, and increased risk of leukemia. A single Ptpn11 mutation evokes all of the major features of Noonan syndrome (Araki et al., 2004). Facial abnormalities include wide-set eyes, broad forehead, a wide nasal base, downward-slanting palpebral fissures, and high arched palate (Sugar et al., 2004; Tartaglia and Gelb, 2005). In addition, mild mental retardation, lymphatic abnormalities, and bleeding problems are variably seen (Singer et al., 1997). A recent report demonstrated effective conservative management of severe open bite and feeding difficulties in Noonan syndrome patients (Fonteles et al., 2013), while a prior case report noted orthognathic surgery in an affected patient that was performed without preoperative or postoperative orthodontic treatment for the occlusal correction (Sugar et al., 2004). Here, we describe a novel case of Noonan syndrome in which orthodontic treatment procedures combined with orthognathic surgery were performed.
CASE REPORT Diagnosis and Etiology A 28-year-old woman with Noonan syndrome was referred to the Department of Oral and Maxillofacial Surgery of Nara Medical University Hospital for orthodontic treatment with a principal concern of masticatory discomfort. She had been diagnosed with Noonan syndrome as a child due to an atrial septal defect and other characteristic findings for which she underwent heart surgery at 8 years of age, then plastic surgery for ptosis at age 15. The patient had a symmetric smile and a Class III molar relationship, along with an anterior open bite from the frontal teeth to premolars. All teeth including the third molars were present. The maxillary midline was 2 mm to the left of the mandibular midline (Fig. 1). A cephalometric examination revealed Class I malocclusion (ANB ¼ 0.48) with a skeletal open bite (FMA ¼ 38.38, gonial angle ¼ 138.28), and both the maxillary and lower incisors showed excessive labial protrusion (Table 1; Fig. 2). A masticatory muscle examination revealed decreased activation of the anterior temporal muscle, while blood findings indicated severe anemia prior to treatment (hemoglobin [Hb] ¼ 5.6 g/dL). Our diagnosis was skeletal open bite associated with Noonan syndrome.
Dr. Kawakami is Assistant Professor, Dr. Yamamoto is Associate Professor, Dr. Shimomura is Research Fellow, and Dr. Kirita is Professor and Chair, Department of Oral and Maxillofacial Surgery, Nara Medical University, Kashihara, Nara, Japan. Submitted June 2014; Revised September 2014; Accepted September 2014. Address correspondence to: Dr. Masayoshi Kawakami, Department of Oral and Maxillofacial Surgery, Nara Medical University, 840 Shijo-cho, Kashihara Nara, 634-8522, Japan. E-mail mkawaka@ naramed-u.ac.jp. DOI: 10.1597/14-196
Treatment Objective and Alternatives The primary objectives of our orthodontic treatment were to close the severe anterior open bite and achieve a Class I molar and canine relationship on both sides, as well as an ideal overjet and overbite. Another objective 253
254
Cleft Palate–Craniofacial Journal, March 2016, Vol. 53 No. 2
FIGURE 1 Pretreatment intraoral photographs.
was to eliminate the abnormal tongue thrust to achieve an unstrained orofacial muscular balance at both rest and during function. One of the treatment options consisted of movement to an upright position and retraction of the anterior teeth to close the open bite using fixed appliances and intermaxillary elastics. However, those alone would not be able to achieve correction of the skeletal open bite. Another plan considered was correction of the open bite and overjet by orofacial myofunctional therapy as previously reported (Fonteles et al., 2013). However, that invasive therapy has limitations for full correction of a severe open bite. Our third option included an orthodontic-surgical approach to correct the open bite, which was chosen by the patient and her parents, because they were primarily concerned about occlusal function. Treatment Plan Orthodontic appliances were used for presurgical alignment including the third molars, and movement of the upper and lower incisors to upright positions, along with extraction of the upper and lower bicuspids. Upward movement of the maxilla was accomplished with a Le Fort I osteotomy, while counterclockwise TABLE 1
rotation of the mandible was done with a sagittal split osteotomy (SSRO). Postsurgical completion of orthodontic leveling was also done. Treatment Progress A preadjusted edgewise appliance (0.018 3 0.025 inches) was placed in both arches, with a 0.016-inch NiTi wire initially used for leveling. Prior to extraction of the upper and lower bicuspids, several laboratory tests were performed, which led us to wait to perform those extractions because of severe iron deficiency anemia (Hb ¼ 5.8 g/dL). Seven months after initial presentation, canal treatment of the upper right first molar was performed for a periapical abscess. One month later, after the anemia had improved (Hb ¼ 10.9 g/dL), all bicuspids were extracted, and retraction of the maxillary and mandibular canines was started. After canine retraction, upper and lower anterior retraction was conducted by closing loops supported by a transpalatal arch between the right and left first molars. The interincisal angle gradually increased over the 2-month period after retraction. The extraction space was then closed, and preoperative treatment was completed with 0.017 3 0.022-inch stainless steel wires.
Cephalometric Analysis Variable
Initial (27 y, 10 m)
Preoperative (30 y, 11 m)
Posttreatment (32 y, 1 m)
Facial angle, deg Mandibular plane (FMA), deg SNA, deg SNB, deg ANB, deg Gonial angle, deg U1 to FH, deg L1 to mandibular plane, deg Overjet, mm Overbite, mm
89.2 38.3 82.1 81.7 0.4 138.2 122.4 98.0 4.0 9.6
88.9 39.8 83.2 82.0 1.2 138.2 115.5 80.0 2.1 5.3
87.3 40.1 85.0 80.7 4.3 134.8 113.5 78.7 4.4 2.6
Kawakami et al., SURGICAL ORTHODONTIC TREATMENT IN NOONAN SYNDROME
FIGURE 2
255
Pretreatment radiographic images. A: Panoramic radiographs. B: Lateral cephalograms. C: Frontal cephalograms.
Next, we planned to perform orthognathic surgery, though waiting was required because of reappearance of anemia (Hb ¼ 6.0 g/dL). That was improved 6 months later (Hb ¼ 12.4 g/dL), then the arches were stabilized with 0.017 3 0.022-inch steel wires with a crimp hock for intraoperative fixation (Fig. 3). After 3 years and 2 months for preoperative orthodontic treatment, orthognathic surgery was undertaken, during which we performed upward movement of the maxillary arch by 5.0 mm using a Le Fort I osteotomy and counterclockwise rotation of the mandible with an SSRO procedure. A horseshoe type osteotomy was also applied for separation of the maxillary bone. Four weeks after surgery, the stabilizing wires were removed and replaced with 0.016-inch Ni-Ti wires in both the upper and lower arches. Then, vertical elastics were worn full-time for 12 months for final positioning of the teeth. The appliances
were removed 11 months after postsurgical orthodontic treatment resumed (age, 32 years 1 month). The patient then used a wraparound type retainer for the upper arch and a spring retainer for the lower arch. Treatment Results The large open bite was closed and occlusion was established with a Class I molar relationship (Fig. 4). Cephalometric superimposition showed a clockwise rotation of the palatal plane and decrease in mandibular plane angle (Table 1; Fig. 5). Both upper and lower incisors were moved to upright positions, which corrected the overbite and overjet (Fig. 6). The patient showed no clinical symptoms of anemia, with the hemoglobin level at 10.2 g/dL.
256
Cleft Palate–Craniofacial Journal, March 2016, Vol. 53 No. 2
FIGURE 3 Intraoral photographs obtained prior to orthognathic surgery.
DISCUSSION Individuals with Noonan syndrome are often complicated with congenital heart disease, with pulmonic stenosis resulting from dysplastic valve leaflets seen as the most frequent manifestation. The present patient had an atrial septal defect and underwent surgery for its repair, with the diagnosis of Noonan syndrome established from preoperative examination findings. Patients with Noonan syndrome have various types of bleeding disorders, though most are reported to be mild (Witt et al., 1988; Singer et al., 1997). Although our patient did not have a bleeding problem, severe anemia was present and we often referred her to the Department of Internal Medicine of our hospital for detailed examinations, which revealed a very low level of hemoglobin. The presence of anemia delayed our decision for tooth extractions and orthognathic surgery. Additionally, she manifested a dry mouth condition that could lead to accumulation of dental calculus and debris, and the reduced salivary secretion made it difficult to control oral hygiene and dental plaque.
FIGURE 4 Posttreatment intraoral photographs.
Our patient had marked mandibular prognathism with an anterior open bite, along with protruding anterior teeth and a Class III molar relationship. An electromyographic examination showed low activities in the masseter, genioglossus, and anterior part of the temporalis, which were considered to be related to the open bite. The skeletal pattern was similar to that in a case reported by Sugar et al. (1994), who used maxillary advancement with a Le Fort I osteotomy without preorthodontic or postorthodontic treatments. On the other hand, we accomplished orthodontic treatment using orthognathic surgery for our patient with Noonan syndrome. Prior to the operation, we moved the upper and lower anterior teeth to upright positions by extraction of the upper and lower bicuspids to establish the postoperative occlusion. One of the craniofacial traits of Noonan syndrome is a high-arched palate with an open bite, while there are also a few descriptions of a narrow high-arched palate in such patients. (Horowitz and Morishima, 1974; Okada et al., 2003; Emral and Akcam, 2009). A high-arched palate with an open bite can be explained by early closure of the cranial
Kawakami et al., SURGICAL ORTHODONTIC TREATMENT IN NOONAN SYNDROME
257
FIGURE 5 A: Posttreatment lateral cephalograms. B: Superimposed lateral cephalometric tracing registered with the S-N plane. Pretreatment, solid line; posttreatment, dotted line. C: Panoramic radiograph.
sutures, which might influence the growth of the dental arch, resulting in a lack of palatal suture growth. A Ptpn11 (i.e., Shp2) mutation occurs in approximately half of Noonan patients, and Ptpn11 mutant mice show craniofacial abnormalities similar to those seen in the syndrome (Araki et al., 2004). The craniofacial characteristics of these mice are a result of reduced skull length and a wider and blunter snout. These characteristics were also observed in the present patient. The open bite in the present case was associated with increased vertical facial angle and the facial height (Fig. 2). For the severe skeletal open bite condition, we performed surgery using a combination of a Le Fort I procedure with a horseshoe osteotomy for the maxilla, which was effective for superior repositioning of the maxillary molar and counterclockwise rotation of the occlusal plane, and decreased the lower facial height with a high-arched palate. Postoperative changes that occur in the maxilla following a combination osteotomy are comparatively stable (Harada
et al., 2002). We confirmed the advantages of that combined surgery and found it useful for reliable superior repositioning of the maxilla, especially in the posterior portion. Furthermore, cephalometric data revealed that the orthodontic/surgical procedures effectively decreased the maxillary and mandibular lengths and the lowered the anterior facial height, while the basal relationship and upright positions of the maxillary and mandibular incisors were also improved. Even though upward movement of the maxilla was performed, there was no decrease in lower anterior face height, which was probably due to the extrusive mechanics utilized, such as up and down elastics for postoperative treatment. The results in this case suggest that low levels of soft tissue and jaw musculature functions have influence on the evolution of open bite. Changes in craniofacial function cause deviations in craniofacial development, resulting in facial skeletal discrepancies and malocclusions (Profitt, 2007). In addition, reduced labial muscle activity may allow
258
Cleft Palate–Craniofacial Journal, March 2016, Vol. 53 No. 2
Therefore, orthodontic treatment and orthognathic surgery are necessary procedures for full correction of severe open bite. Despite the great improvement in occlusion, a compromised occlusal result was achieved in the present case. Normal overbite and overjet are evident, while residual dental space remains in the lower arch. This less than ideal intercuspation may be partially explained by reduced masticatory activities. CONCLUSION Surgical orthodontic treatment with two-jaw surgery provided good results for treatment of a patient with Noonan syndrome with a severe open bite. REFERENCES
FIGURE 6 Regional superimpositions. A: Maxilla tracing registered with palatal plane at Ptm. B: Mandible tracing registered with mandibular plane at Me. Pretreatment, solid line; posttreatment, dotted line.
excessive displacement of the jaws, inducing significant vertical growth and severe protrusion of both the upper and lower incisors. A recent case report showed that myofunctional therapy for severe open bite in a Noonan syndrome patient increased muscle tonus and regained occlusion along with improvement in masticatory ability (Fonteles et al., 2013). However, this approach has intrinsic limitations.
Araki T, Mohi MG, Ismat FA, Bronson RT, Williams IR, Kutok JL, Yamg W, Pao LI, Gilliand DG, Epstein JA, et al. Mouse model of Noonan syndrome reveals cell type- and gene dosage-dependent effects of Ptpn11 mutation. Nature Medicine. 2004;10:849–857. Asokan S, Muthu MS, Rathna PV. Noonan syndrome: a case report. J Indian Soc Pedod Prev Dent. 2007;25:144–147. Emral ME, Akcam MO. Noonan syndrome: a case report. J Oral Sci. 2009;51:301–306. Fonteles CSR, Mota AC, Lima RA, Borges PC, Silveira A. Conservative management of severe open bite and feeding difficulties in patient with Noonan syndrome. Cleft Palate Craniofac J. 2013;50:242–248. Harada K, Sumida E, Enomoto S, Omura K. Post-operative stability of the maxilla treated with Le Fort I and horseshoe osteotomies in bimaxillary surgery. Eur J Orthod. 2002;24:471–476. Horowitz SL, Morishima A. Palatal abnormalities in the syndrome of gonadal dysgenesis and its variants and in Noonan’s syndrome. Oral Surg Oral Med Oral Pathol. 1974;38:839–844. Okada M, Sasaki N, Kaihara Y, Okada R, Amano H, Miura K, Kozai K. Oral findings in Noonan syndrome: report of a case. J Oral Sci. 2003;45:117–121. Profitt WR. The etiology of orthodontic problems. In: Profitt WR, Fields HW, Sarver DM, eds. Contemporary Orthodontics. 4th ed. St. Louis, MO: Mosby Elsevier; 2007:130–161. Singer ST, Hurst D, Addiego JE Jr. Bleeding disorders in Noonan syndrome: three case reports and review of the literature. J Pediatr Hematol Oncol. 1997;19:130–134. Sugar AW, Ezsias A, Bloom AL, Morcos WE. Orthognathic surgery in a patient with Noonan syndrome. J Oral Maxillofac Surg. 1994;52:421–425. Tartaglia M, Gelb BD. Noonan syndrome and related disorders: genetics and pathogenesis. Annu Rev Genomics Hum Genet. 2005;6:45–68. Witt DR, McGillivary BC, Allanson JE, Hughes HE, Hathaway WE, Zipursky A, Hall JG. Bleeding diathesis in Noonan syndrome: a common association. Am J Med Gent. 1988;31:305–317.
