21: Orthodontics and Craniofacial Deformities

CHAPTER 21

Orthodontics and Craniofacial Deformities

Kirt E. Simmons

The treatment of patients affected by clefting and craniofacial anomalies can be both extremely rewarding and incredibly frustrating, owing to the myriad difficulties involved and the often long duration of treatment required. Care of these patients calls upon all the orthodontist’s skills and knowledge necessary to treat everyday children and adults, as well as additional skills and knowledge related to the unique challenges these patients often present. These challenges can include differences in psychological states of the patients and their parents, abnormalities of dental number, size, morphology, position, eruptive potential, etc., as well as similar abnormalities of the facial and jaw components. Concomitant medical conditions can also affect the treatment options, provision of care, and potential outcomes. The following chapter is dedicated to the practitioners willing to commit to the persistence, patience, and unique demands required by these patients.

1 What is the most common craniofacial deformity?

The most common craniofacial deformity is orofacial clefting, which affects all populations. Approximately 1 in 500–700 births will have some form of orofacial clefting: cleft of the lip, palate, or some combination of both.< ?xml:namespace prefix = "mbp" />1 These clefts may be complete or incomplete, involve one or both sides, be isolated (i.e., non-syndromic), or be part of a more general syndrome (in about 20% of cases); they are variable in their distortions of the affected tissues and subsequent clinical presentations.

2 What are the common types of facial clefts?

Cleft lip only, which may be unilateral or bilateral and may or may not involve the maxillary alveolus.
Cleft palate only, which can vary from a submucous cleft of the palate (overtly it appears intact but the muscle and/or bone of the palate are deficient) to a complete cleft of the palate, even involving the alveolus.

    Unilateral cleft lip and palate
    Bilateral cleft lip and palate
    Each of these can be further subdivided into complete (in which the cleft extends completely through the lip and/or palate) or incomplete (in which some portion of the structure is not cleft) clefts.

3 When might cleft-affected patients be treated orthodontically/orthopedically?

Effective treatment of this type requires a specialized knowledge of these patients’ unique features and typically involves several periods of time at various ages. Because of the intensive nature of orthodontic therapy, performing it in stages is preferable to long-term continuous treatment. The potential treatment stages to be considered are based on four developmental stages: infancy, primary dentition, mixed dentition, and permanent dentition. Orthodontic treatment will often be provided at several of these developmental stages.

4 What is “presurgical orthopedics”?

Orthopedic treatment of cleft-affected infants provided prior to any surgical lip or palate procedures, or presurgical orthopedics, was once routinely accepted as a necessary practice because of the dramatically distorted appearance of the maxilla at birth (Fig. 21-1). Orthopedic alignment of maxillary segments, followed by bone grafting at the time of lip and/or palate closure, was proposed to allow normal function, growth, and development.2 However, this early surgery was ultimately shown to affect future growth and development negatively,3,4 as compared with the relatively normal development observed in untreated adults.5

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FIG 21-1 A and B, Unrepaired complete clefts of the lip and palate. Bilateral; note the posterior arch collapse, the protrusive premaxilla, short columella, and separation of the lip segments. C, Unilateral; note the distorted alveolar segments.

Although still controversial, presurgical orthopedic treatment with appliances addresses excessive maxillary distortion, especially in cases of bilateral cleft. Pin- or screw-retained “jackscrew” type or spring-loaded appliances (Fig. 21-2, A and B) can be used to expand posterior segments. Retraction of the premaxillary segments can be achieved with an additional screw component, with elastic bands between the premaxillary segment and the posterior portion, or by extraoral elastic traction across the premaxilla (Fig. 21-2, C), either alone or in conjunction with an active posterior expansion appliance or passive posterior “molding” appliance. At some craniofacial centers, preliminary surgical procedures are performed following expansion, including lip adhesion, wherein elastic force of the healing lip retracts the premaxilla.

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FIG 21-2 A, An infant orthopedic expansion appliance using a midpalatal screw (jackscrew) and posterior hinge to expand the anterior portion of the lateral palatal shelves to allow retraction of the premaxilla. B, Palatal side of appliance. Note the stainless-steel “staples” that are driven into the palate to maintain the appliance. C, An extraoral elastic traction band placed across the premaxilla to provide retraction following expansion of the posterior segments.

Today, at some centers advocating early orthopedic treatment, primary alveolar bone grafting or periosteoplasty is performed at the same time as lip closure, to provide a better arch form, fewer fistulae, and decreased need for secondary bone grafting. Treatment choice must be determined by balancing the potential iatrogenic risks of presurgical expansion (e.g., damage to tooth buds, aspiration of materials, anesthetic and surgical procedural risks) with the positive benefits of treatment outcomes.58 The most recent addition to presurgical orthopedics is a modification of these earlier techniques to include a nasal stent and taping to mold the cleft nose and columella.9 Immediate surgical results are quite positive, but the long-term effects are unknown at this time.

5 What orthodontic treatment may be indicated for cleft-affected patients in the primary dentition?

Depending upon developmental milestones, surgical closure of the palate is performed between 9 and 18 months of age, leaving a cleft of the maxillary alveolus and buccal and/or lingual fistulae. Orthodontic treatment during this phase is relatively rare, involving treatment of deleterious habits, functional shifts, or space loss after premature tooth loss. Fixed or removable habit appliances can be used to address digit habits and to correct crossbites (Fig. 21-3).

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FIG 21-3 A digit-sucking appliance in a cleft-affected patient.

Crossbite interference should be eliminated to prevent consequent unfavorable jaw growth, particularly if the patient has a functional shift of the mandible for intercuspation. Usually, selective reduction of the interfering teeth suffices, but some cases require orthodontic expansion, which may involve anterior and/or posterior expansion as well as long-term retention. However, if the maxilla has no bony continuity across the palate or alveolus, the corrected crossbite should be retained until secondary bone grafting provides that continuity.

Patients should be monitored for dental and overall development during this phase. In short-statured patients especially, delayed dental development may be due to growth hormone deficiency, because clefting is often associated with other midline defects, including pituitary and cardiovascular anomalies.

6 What orthodontic treatment may be indicated for cleft-affected patients in the mixed dentition?

EVALUATION OF NEEDS/TREATMENT PLANNING

Orthodontic evaluation and the development of long-term treatment objectives are needed at the start of this phase because of relatively rapid changes, as well as the developing social and self-awareness of the patient.10 Assessment will involve standard orthodontic records, as well as selected periapical and/or occlusal radiographs to assess missing or supernumerary teeth and/or bone quantity and anatomy in the cleft site.

Most patients with cleft alveoli have a posterior crossbite and malaligned maxillary incisors at this stage. The collapse of the maxillary segments, especially in bilateral cases, can be severe (Fig. 21-4). These patients will need expansion of the collapsed maxillary segment(s) and/or elimination of traumatic occlusion in preparation for alveolar bone grafting. Bone grafting is ideally performed when root formation of the erupting adjacent lateral incisor or canine is one half to two thirds complete11,12 so that complete eruption of the adjacent tooth, with its accompanying periodontal attachment, will inhibit further bone resorption of the graft.11,13 Although these teeth generally erupt spontaneously, it is occasionally necessary to uncover them surgically and induce eruption via orthodontic traction.11

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FIG 21-4 Patient with repaired bilateral cleft lip and palate exhibiting severe arch collapse of the posterior segments.

ELIMINATION OF TRAUMATIC OCCLUSION

A stable maxilla is necessary for bone graft healing. Thus, traumatic occlusion of teeth in the cleft region should be eliminated, when possible, through alignment of the offending (usually maxillary incisor) teeth. Great care must be used to prevent moving the roots into the cleft site, and adequate retention is recommended to allow reformation of the cortical bone along the root prior to surgical exposure. It is often best to delay orthodontic alignment until after the graft because commonly there is only a thin layer of bone along the cleft side of the roots of adjacent teeth (Fig. 21-5, A). Denudation of roots during grafting can result in periodontal defects, ankylosis, root resorption, and/or decreased alveolar bone mass upon healing. If traumatic occlusion cannot be eliminated prior to graft placement, a full-time bite splint can prevent traumatic occlusion while the graft heals.

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FIG 21-5 Examples of expansion appliances in cleft-affected patients. A, Radiograph of a “W”-arch; note the thin layer of bone on the lateral aspect of the central incisor in the cleft edge. B, Removable maxillary expansion appliance; note the lingual shelf of acrylic on the side of the greater segment to utilize the lower arch to reinforce anchorage and provide greater expansion of the lesser segment. Inverted “W” stainless-steel wire spring provides for expansion anteriorly. C, Bonded “fan” appliance in a patient with bilateral cleft lip and palate. The appliance uses posterior occlusal coverage to prevent traumatic occlusion of the incisors, since the premaxilla is flared by the lingual wires. Note that this appliance preferentially expands the anterior portion of the collapsed palatal shelves.

PRE-GRAFT EXPANSION

The amount and timing of pre-graft expansion should be planned in consultation with the surgeon. Whereas expansion is valuable before bone grafting to optimize surgical access, segments must not be expanded beyond the limits of surgical closure. The ideal expansion would provide coordinated maxillary and mandibular arch forms. If this interferes with the graft prognosis, three options are posed: delay the graft until adolescence and unite the segments with orthognathic or distraction surgery; perform the graft with little or no expansion and attempt expansion later (which may require surgical assistance); or accept the crossbite. If the patient is expected to need orthognathic maxillary advancement later, less expansion is indicated. Delaying the graft until adolescence may negatively affect the eruption or orthodontic movement of adjacent teeth, which could cause periodontal defects, caries, and social stigmata. In unilateral cleft-affected patients, further expansion is fairly predictable after alveolar bone grafting, although arch form may be compromised. However, post-graft expansion is less predictable in the bilateral situation, with the increased scarring and lack of a functional maxillary midline suture.

There are several appliance designs that can be used for expansion: fixed-spring appliances (e.g., quad-helix, W-arch or combinations; see Fig. 21-5, A); removable appliances with jackscrew devices or wire springs (Fig. 21-5, B); or fixed jackscrew devices (e.g., “fan” appliance; Fig. 21-5, C). Bilateral clefts with a posteriorly displaced premaxilla may require a separate appliance first to buccalize the premaxilla (Fig. 21-6), followed by the expander (see Fig 21-5, C). The selection of appliances is based on several variables: the direction and extent of expansion needed, the teeth present, the expected resistance, access to the cleft area needed by the surgeon, and the compliance anticipated by the patient. Removable appliances are preferred for optimal hygiene but lend themselves to compliance problems and loss. Fixed appliances cause fewer such problems, but they cause greater hygiene problems that may lead to decalcification and caries. Spring appliances apply lighter forces, under the control of the orthodontist, and the quad-helix provides lighter forces over a greater range than the W-arch. They can also be activated to expand segments differentially, which is quite useful because the lesser segment (or posterior segments in a bilateral cleft) is generally collapsed more anteriorly than posteriorly. However, repeated reactivation of spring-loaded appliances may be necessary to achieve the desired expansion. Jackscrew appliances are very rigid and generate high forces, resulting in rapid movement, but they require activation by the patient or a parent. They provide a specific amount and direction of expansion. Any fistulae present (including those unknown to the patient and/or clinician) will tend to be enlarged during the expansion. Such fistulae are generally closed at the time of the alveolar bone graft. Ideally the appliance should allow unimpeded surgical access. If it is in a position to interfere with surgery, the appliance can be modified beforehand or removed and replaced in the operating room. The appliance should be conducive to good oral hygiene in order to prevent bone graft failure.14 For proper graft healing, expansion should be maintained for 4 to 6 months after surgery, either by retaining the passive expansion appliance or by replacing it with a removable acrylic retainer or fixed lingual arch (Fig. 21-7). With complete bilateral clefting, it is important to stabilize a mobile premaxilla through the time that the graft is incorporated into the host bone.14 This will require 6 weeks to 6 months, depending on graft size, tissue stretch and/or scarring, occlusal stability, and individual bone and soft-tissue healing capacity. A full-time maxillary splint or heavy labial or lingual fixed appliance can provide this stability.

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FIG 21-6 A “trombone”-style appliance uses elastic chain to advance the premaxilla out of crossbite. A separate expansion appliance is then used posteriorly followed by alveolar ridge bone grafting.

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FIG 21-7 A, A fixed lingual arch maintains expansion after placing an alveolar bone graft and incorporating two finger springs to flare the central incisors. B, A modified “W” or lingual arch maintains the expansion obtained, while allowing surgical access for the alveolar bone graft.

An alternative approach advocates alveolar bone grafting at a younger age (5–7 years) followed by orthodontic stimulation of the graft by rapid expansion with a fixed-expansion (e.g., jackscrew type) appliance (see Fig. 21-5, C).15 Proponents of this method claim shorter orthodontic treatment time and prevention of maxillary horizontal hypoplasia. In theory, rapid expansion could elicit an effect similar to distraction osteogenesis at the cleft site. Initial maxillary incisor alignment can be done with fixed orthodontic appliances immediately after the graft. Generally, the patient then takes a break from active treatment and is placed in retention. If necessary, missing or unerupted teeth may be masked with a removable acrylic retainer with plastic pontics, and a temporary bonded lingual retainer (0.0175-inch multi-strand archwire) can be used to retain spaced incisors until comprehensive orthodontic treatment is begun.

MAXILLARY PROTRACTION

Following graft stabilization and initial incisor alignment, an orthodontic assessment is indicated to evaluate the patient’s pattern of maxillary and mandibular growth. Discordant monozygotic twin studies have revealed differences based on the type and severity of the cleft.16 Growth is essentially unaffected in patients with clefts of only the lip and alveolus. Cleft palate can result only in a shorter posterior face height, a steeper mandibular plane angle, and retrognathia. Complete unilateral cleft lip and palate can lead to failure of anterior maxillary growth, resulting in posterior and inferior displacement. Patients with very flat profiles, increased face heights, and/or Class III skeletal relationships will generally exhibit a worsening of their condition with further growth. Significant skeletal deformities are often best treated with combined orthodontics and surgery, possibly in multiple stages. Young (∼8 years1719) patients with mild maxillary deficient clefts may benefit from orthopedic forces for maxillary protraction via bonded full occlusal coverage acrylic splints19 or fixed banded1718 intraoral appliances, with extraoral protraction force applied via elastic force to a facial mask. These masks differ in their various pads, bands, and frame styles, and even include an American football-style helmet.1720 This treatment can effectively correct anterior crossbites and improve the prognathic profile through a limited maxillary skeletal advancement (1–3 mm), maxillary denta/>

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Jan 1, 2015 | Posted by in Orthodontics | Comments Off on 21: Orthodontics and Craniofacial Deformities
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