Unilateral Cleft Lip and Palate: Timing of Alveolar Bone Graft and Maxillary Growth
A boy aged 8 years 6 months with a repaired left unilateral cleft lip and palate attends for orthodontic assessment. He has a mixed dentition with a Class III tendency, an anterior crossbite of the upper left central incisor, and a 4 mm alveolar defect on the left. The upper left permanent lateral incisor is absent and the upper left permanent canine is unerupted and palpable in the alveolus. The cleft team is considering alveolar bone grafting. The parents ask whether the graft should be done now, whether orthodontics should come before or after the graft, and whether the crossbite can be corrected.
1. Discuss the timing of alveolar bone grafting in this patient and the relationship between orthodontic preparation and the graft.
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Alveolar bone grafting in cleft patients is most commonly performed in the mixed dentition, typically between about 8 and 11 years of age, before the eruption of the permanent canine in the region of the defect. The rationale is that the graft provides bone support for the erupting canine and for the teeth adjacent to the cleft, closes any oronasal fistula, and provides a bony base for the nasal alar support. Grafting after the canine has erupted is less predictable because the tooth may erupt through the defect without bony support, and grafting too early, before the permanent incisors and canine are sufficiently developed, risks resorption of the graft and interference with maxillary growth.
In this patient, the canine is unerupted and palpable, so the window for grafting is open. The decision should be made with the cleft team and should include assessment of the canine's root development, the size of the defect, and the state of the erupted dentition. The crossbite of the upper left central incisor should be corrected before or around the time of grafting, because the tooth needs to be positioned over the graft site to allow the graft to be placed and to allow the tooth to erupt into a stable position. Orthodontic preparation, including expansion of the maxilla if needed and alignment of the incisors, is usually done before grafting, and the graft is then protected during the healing period.
The parents should be told that the graft is a staged procedure and that further orthodontic treatment and possibly orthognathic surgery will be needed later. The absent lateral incisor raises the question of space management: the canine may be substituted for the lateral incisor, or the space may be closed or opened for an implant later. That decision should be deferred until the canine has erupted and the graft has consolidated.
2. The parents ask whether the Class III tendency will correct itself after the graft. How do you explain the growth implications and the long-term plan?
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The Class III tendency will not correct itself after the graft. Alveolar bone grafting addresses the bony defect and supports the teeth adjacent to the cleft, but it does not change the underlying maxillary growth deficiency that produces the Class III pattern in many cleft patients. In fact, maxillary growth in cleft patients is often reduced, and the Class III tendency may become more apparent during the pubertal growth spurt. The graft is therefore a local reconstructive procedure, not a growth-modifying one.
The long-term plan should include: continued growth monitoring with serial cephalometric and dental casts; orthodontic treatment to align the teeth and manage the space of the absent lateral incisor; and, in a significant proportion of cleft patients, orthognathic surgery after growth is complete to correct the skeletal Class III relationship. The parents should be told that the timing of surgery, if needed, is usually in the late teens or early twenties, after growth has ceased, and that the graft may need to be reassessed at that time.
The parents should also be told that the crossbite correction and the graft are not the end of treatment. The patient will need long-term follow-up by the cleft team, including speech and language review, hearing assessment, and psychological support. The absent lateral incisor should be discussed in terms of the eventual plan: canine substitution may be possible, but the canine's size and colour may differ from the lateral incisor, and an implant may be preferred later. The decision should be made with the patient as he matures, and the parents should be reassured that the team will guide them through each stage.