Abstract
Distraction osteogenesis (DO) has been used recently to correct maxillary hypoplasia with predictable and stable results. In patients with clefts of the secondary palate, DO can also be used to aid in vertical alveolus augmentation and rapid orthodontic tooth movement. If an osteotomized dental arch can be transported to a new position without complications, it would reduce or eliminate the need for a secondary bone graft to the cleft alveolus in cleft patients and help prevent dentoalveolar defects by approximating the native alveolar bone and gingiva. Mobilizing a segment in the dentoalveolar region also results in the creation of new bone and attached gingiva. This report shows that the application of DO for skeletal expansion and rapid movement of tooth-bone segments should receive more careful consideration in the treatment of patients with clefts of the palate.
INTRODUCTION
Cleft lip and palate are common congenital deformities in the oromaxillary area.1 This birth defect causes several functional and esthetic problems because of defects in the soft and hard tissues leading to nose deviation and formation of scar tissue after surgery.2–4 A systematic approach is thus required for cleft palate patients, which includes timing of surgery by a surgeon, caries control by a pedodontist, attention to hearing problem by an ENT specialist, speech therapy, and growth modification by an orthodontist.5
In cleft lip and palate patients, early surgical corrections are usually performed to improve esthetics and function. These early surgeries tend to result in poor skeletal and dental growth in the transverse and anteroposterior planes, especially in the maxilla. Also, the upper dentition is often collapsed because of missing teeth.6 In children, orthodontics that uses orthopedic means can be used to correct these problems.7 In adults, gingival recession, hearing problem, and relapse commonly follow arch expansion with quid-helix therapy or other types of conventional tooth movement appliances, thereby necessitating the need for surgical expansion.8–10 In a dentition with missing lateral incisors in the cleft area, an autogenous bone graft is usually required before canine eruption. This, however, may lead to the occurrence of an oronasal fistula during expansion and tooth alignment and the necessity for an autogenous bone graft.
Distraction osteogenesis (DO) was first used for correction of the craniofacial skeleton in the early 1990s.11 McCarthy et al12 reported using distraction to lengthen the mandible in patients with hemifacial microsomia. Figuero and Polley13 reported success with no significant complications when DO was used to advance the maxilla in children with cleft lip and palate. Recently, DO was used to advance the maxilla in patients with cleft palate;14,15 however, little has been reported on the use of DO for maxillary expansion and closure of the cleft alveolus. This article reports a case of dentoalveolar distraction in a repaired unilateral alveolar cleft patient using a tooth-borne–type distractor.
CASE REPORT
A 20-year-old Asian female with a unilateral cleft lip and palate presented with a complaint of an oronasal communication. The lip had been repaired at three months and the palate at two years of age. There had been no treatment after two years of age.
Facial analysis showed a slightly concave profile with no facial asymmetry (Figure 1A). Teeth 22 and 25 were missing, and there was root resorption on teeth 11 and 24. The upper arch was omega (Ω) shaped, there was a crossbite in the anterior and posterior area, and the dental midline deviated to the left side. An oronasal fistula perforation was present on the cleft side (Figure 1B).
Facial and intraoral photo, cephalogram, panorama of pretreatment record
Skeletally, the patient showed a Class III pattern with maxillary hypoplasia and a prognathic mandible. To address her complaints and to treat her skeletal and dental deformities, the following treatment plan was implemented:
DO application for maxillary mobilization, expansion, and segmental mesial transportation.
Orthognathic surgery to correct the A-P skeletal discrepancy.
DO for maxillary mobilization, expansion, and segmental mesial transportation
In this patient with an arch length deficiency, we chose to address the transverse problem present with DO to correct the omega-shaped arch in the maxilla without the bending of bone and tissue tension. An osteotomy was performed by way of an enveloped soft tissue incision under 2% lidocaine infiltrations. A horizontal osteotomy must be made two mm above the canine to the first molar apex and must penetrate to the palatal cortex. The same procedure was performed on the contralateral side. A vertical osteotomy cut was made between the central incisor and canine and between first molar and second molar on both sides (Figure 2). A hyrax-type appliance was then cemented to the first premolars and first molars (Figure 3A).
Photo of upper dentition. (A) Before distraction. (B) Upper dentition after distraction. (C) Initial alignment after a three-week retention period. (D) Increased cleft alveolus after the achieved upper arch
Photo of upper dentition. (A) Before distraction. (B) Upper dentition after distraction. (C) Initial alignment after a three-week retention period. (D) Increased cleft alveolus after the achieved upper arch
The patient tolerated the surgery well. A healing period of seven days was allowed, and on the eighth day the patient was instructed to turn the Hyrax appliance twice in the morning and twice in the evening until the next orthodontic visit, four days later. At this appointment, the patient was assessed for the periodontal condition. The patient was advised to continue turning the appliance in a similar fashion for three more days and then reduce the number of turns to twice daily for a total of 28 turns. A total of approximately seven mm of expansion was achieved (Figure 3B).
After a stabilizing period of three weeks, orthodontic brackets were bonded on the upper dentition to align the teeth. We initially used a light force with a 0.014-inch NiTi wire (Figure 3C). The period of alignment in the upper dentition was about five months (Figure 3D). During this period, the patient had no gingival recession, no arch collapse, and no alveolar crest resorption.
After the surgically-assisted expansion and alignment of the upper arch, we noticed an increase in the size of the alveolar cleft, possibly due to the expansion. We decided to close the cleft by a forward transport of bone using a segment from teeth 23 to 24. To achieve this, a surgical incision was made at the upper left side from the medial side of the canine to the distal side of the first premolar. A screw was implanted for verification of movement of the bony segment.
A tooth-borne distraction device was constructed consisting of an orthodontic screw (Dentarum Co), an .018″ × .025″ tube, and an .016″ × .022″ stainless steel (SS) wire (Figure 4A). The construction of this appliance was simple in that the tube was welded to an orthodontic screw, and a properly bent SS wire was inserted into the tube. This appliance was placed on teeth 24 and 26 (Figure 4B). Following the same procedure of DO for transportation as was followed for maxillary expansion, the bone segment was moved mesially and the size of the cleft alveolus was decreased. The canine tipped forward, and tooth 24 showed a mesial-in rotation. Consequently, we stopped the mesial transportation of the bone segment and looked forward to some rotational relapse in the transported area (Figure 4C). After a consolidation period of two weeks, the first molar was moved into the newly created bone-regenerated area.
Closure mechanism of cleft alveolus with transport bone segment. (A) Used distractor. (B) Delivery tooth-borne distractor after corticotomy. (C) Tipping movement occurred after distraction for 14 days, and in X-ray view, it was verified that the bone segment was tipped forward.
Closure mechanism of cleft alveolus with transport bone segment. (A) Used distractor. (B) Delivery tooth-borne distractor after corticotomy. (C) Tipping movement occurred after distraction for 14 days, and in X-ray view, it was verified that the bone segment was tipped forward.
Orthognathic surgery to correct the A-P skeletal discrepancy
After correction of the transverse discrepancy and reduction of the size of the cleft in the alveolus, an autogenous bone graft was performed in the residual cleft area and a mandibular setback was carried out under general anesthesia. In this case, we did not do a maxillary advancement with DO because the patient needed a mandibular setback.
Postsurgical orthodontic treatment achieved a good occlusion, but the patient was not satisfied with the shape of her nose. After orthodontic treatment was performed, prosthodontic treatment was planned for the cleft alveolar area (Figure 5).
Facial and intraoral photo, cephalogram, panorama of posttreatment record
DISCUSSION
DO is a process of growing new bone by intentionally stretching preexisting bone tissue. In routine DO, the bone is mechanically increased using a distractor across the osteotomy site. In the osteotomy site, new bone is created during distraction.16 Many authors have reported successful results with corrective osteotomies followed by gradual bone distraction for mandibular lengthening17 and widening,18 alveolar ridge augmentation,11 and forward movement of maxilla.19
DO can also be applied to patients with cleft lip and palate. A well-known modality is surgically assisted maxillary expansion in adults that transversely distracts the hard palate through the midpalatal suture.20,21 This technique reduces the complications of rapid maxillary expansion, which relies on tooth abutments alone without surgical assistance and can result in gingival recession, ankylosis, and root resorption.22–24 The technique reported in this study can be used for corrections in collapsed arches in cleft palate patients.
After maxillary expansion was completed, the patient did not suffer any root resorption, tooth tipping, gingival recession, or bone gap after osteotomy. We have also done rapid tooth movement into newly created bone areas without complications. However, the size of the cleft was increased after finishing tooth alignment.
Concerning alveolar grafting into the cleft alveolar or oronasal fistula area, successes have been reported in cleft patients,25 but stabilizing the alveolar ridge and closing persistent oronasal fistulae after bone grafting are necessary. With larger clefts of the alveolus, more failure is likely because of the limited available attached gingiva.26 It is necessary to reduce the size of the cleft for alveolar bone grafting success.
Recently, Liou et al27 reported on the reduction of alveolar cleft size with DO and rapid tooth movement into newly generated bone areas. In our case, we used a tooth-borne appliance to approximate the bony surfaces across a wide gap, with regeneration of attached gingiva. During mesial movement of the distal segment, the segment was rotated and tipped into the gap. It is probable that we did not use a force application at the center of resistance of the segment, and this is one of the limitations of tooth-borne appliances.28,29 As a result, we recommend the use of tooth- and bone-borne appliances for accurate force application based on an accurate determination of the center of resistance for DO. In recent years, DO has been applied successfully to correct maxillary hypoplasia in cleft lip and palate patients with predictable and stable results. Subsequent research has reported on the mechanical considerations, phonetic changes, and profile changes after DO in cleft lip and palate patients.30,31 For successful results using this procedure, it is important to have an accurate prediction of the desired location and direction of action of the distractor.
CONCLUSIONS
For DO treatment of patients with cleft lip and palate, it is important to have a proper treatment plan based on biologic knowledge and mechanical consideration of the device to be used. If an orthodontist uses DO for cleft lip and palate patients with an appropriate device, it will open the way to supplement conventional treatment.
Acknowledgments
This article was supported by 2002 grants from University of Wonkwang.
REFERENCES
Author notes
bAssistant Professor, Dept. of Orthodontics and Pedodontics, University of Michigan, Ann Arbor, MI
cAssistant Professor, Dept. of Oromaxillofacial Surgery, University of Wonkwang, Ik San, Korea
Corresponding author: Ki Chul Tae, Department of Orthodontics, University of Wonkwang, Dental Institute, Ik San, Korea. ([email protected])