September 2019 HSC Section 1 Congenital and Pediatric Problems

Dao & Goudy

crossbite and improve access during closure of the nasal floor. The degree of expansion should be limited in those with a bilateral cleft and a large palatal fistula. It normally occurs over a time period of 4 to 6 months 28 and the device should be left in place for 3 additional months after the grafting has been completed during grafting consolidation. Presurgical expansion is typically preferred, al- though postsurgical expansion also is an option, especially with bilateral clefts to allow greater ease of closure of the palatal mucosa. In these cases, grafting consolidation is allowed for 8 weeks before use of the expansion appliance. There is belief among some that postsurgical expansion places the grafting site under a dynamic load during healing, which may lead to improved bone consolidation. 29 Surgical technique Repair of the alveolar cleft involves closure of the oronasal fistula and reconstruction of the alveolus with bone graft between the nasal and oral layers. Complete coverage of the graft is critical to its overall success and is achieved by advancing a keratinized buccal mucoperiosteal flap from the lesser maxillary segment on the cleft side. The anticipated bone height is only as high as the alve- olar bone level of the patient’s adjacent teeth. Bone graft beyond this point leads to unnecessary increased tension on the closure and does not result in additional alveolar bone height. The gold standard involves using an autogenous graft usu- ally harvested from the anterior iliac crest. Autoge- nous bone offers several advantages over other options, such as osteogenic activity and osteoin- ductive capability given the presence of viable cells and growth factors while not causing an immunologic reaction. Downsides involve the donor site morbidity and increased operative time. Calvarial bone has been advocated in the past, although it has been shown to have a decreased success rate when compared with the iliac crest (80% vs 93%). 30 Alternative bone graft products There are several alternative bone graft products one may use including allogenic, alloplastic, and most recently bone morphogenetic proteins (BMP). Allogenic bone from a cadaveric source has no osteogenic properties, although results have been comparable with autogenous bone. 31 Allogenic bone may also be mixed with autogenous bone to enhance the graft volume in large clefts, which may spare the patient bilateral iliac crest har- vesting. Recombinant human BMP is an emerging alternative that is involved in maintenance of the mature skeleton. Three BMPs have the ability to

to consider the development and position of the permanent incisor, which is often fully erupted by 7 or 8 years of age and may therefore have compromised periodontal support. Vertical alve- olar bone height after grafting is determined by the alveolar bone height of this adjacent incisor, and bone height is only optimized if grafting is completed before completion of the incisor erup- tion. Preservation of alveolar bone height not only improves function and health of future teeth and implants, but also improves overall cosme- sis. 26 Timing within this age range may also be influenced by the eruption of the maxillary perma- nent first molar, which usually occurs between 6 and 7 years of age. Because many clefts require palatal expansion before repair the presence of this first molar allows an orthodontist to place the palatal expansion device. Finally, late alveolar grafting is done after 13 years of age because this is associated with a greater risk of complica- tions, such as infection, wound breakdown, and graft loss. 27 With all factors considered optimal cleft repair is usually done between the ages of 5 and 7. Patient evaluation The patient evaluation should start with a well- documented history of all prior cleft surgeries and thorough physical examination, which in- cludes taking note of all dentition adjacent to and within the cleft along with the size of the cleft and fistulae present. It is important to also appre- ciate dental arch form, degree of arch collapse, crossbite malocclusion, and position of the pre- maxilla in a bilateral cleft. Imaging is essential and typically a panoramic radiograph is satisfac- tory. A medical-grade computed tomography is not recommended in children at the optimal age for alveolar cleft repair given the higher radiation exposure, although cone beam computed tomog- raphy is becoming popular. Mobile primary teeth, exposed supernumerary teeth, and exposed per- manent lateral incisors should all be removed 6 to 8 weeks before repair because their presence may make palatal closing difficult or impossible. Palatal expansion devices that contact the palate should be removed 3 to 4 weeks before repair to allow resolution of any palatal inflammation if it is present. Expansion may be maintained with a removable device to allow proper oral hygiene and cleaning. Presurgical orthodontic preparation The goal of presurgical orthodontic preparation is palatal expansion to improve dental arch relation- ships before grafting and surgical access to the alveolar cleft itself. Expansion may also reduce

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