Jung-Wei Chen DDS, MS, PhD
Cleft lip and cleft palate are among the most common birth defects in the United States. Presurgical orthopedic treatment of the cleft lip and palate has become the treatment of choice for many craniofacial teams. The purpose of this article is to address the importance of the dentist’s role on the craniofacial team, the benefits of using a presurgical nasal alveolar molding appliance (PNAM) prior to surgical lip repair, and to describe the procedure for treating patients with the PNAM appliance. The PNAM appliance not only molds the affected intraoral and extraoral structures, but also provides nasal support while molding the collapsed nostrils. The PNAM appliance is the treatment of choice for unilateral and bilateral cleft lip and palate patients. For several reasons the use of this appliance enhances the chances of a favorable outcome and, thereby, improves the patient’s quality of life.
Cleft lip/palate cases occur in one of every 700 to 1,000 newborns in the United States.1, 2 The causes of cleft lip and palate can be multifactorial: genetics, drugs, vitamin deficiency or excess, cigarette smoking. Environmental and other unknown factors may contribute. Superstitions in some cultures attribute the cause of cleft lip and palate to a jinx. For example, in the Chinese culture some believe doing hard physical labor during the mother’s pregnancy could cause cleft lip and palate. This malady has sometimes been connected, in the Mexican culture, to the use of scissors during pregnancy. Regardless of the cause, infants born with cleft lip and palate face multiple, life-long health problems that need to be resolved. This protracted treatment journey can be very difficult for patients, parents and health professionals.
In the United States, infants born with cleft lip and palate will be referred to a craniofacial team that consists of a pediatrician, plastic surgeon, feeding consultant, speech pathologist, ENT specialist, pediatric dentist, orthodontist, oral surgeon, prosthodontist, social worker, etc. Dentists play an important role in the treatment, providing presurgical soft/hard tissue molding, regular dental checkups due to high caries risk, orthodontic treatment, orthognathic surgery, and speech prostheses.
Dentist’s role in treating cleft lip and cleft palate patient
From birth into early teen years, regular dental checkups and an aggressive oral hygiene prevention plan are important for the cleft lip and palate patient. The initial appointment should be scheduled around the time of the first tooth eruption. Cleft lip/palate patients have a higher incidence of congenitally missing and supernumerary teeth, enamel hypoplasia, hypocalcification and ectopic eruption at the affected site. A cleft lip and palate patient may require follow-up dental visits at less than six-month intervals to receive sufficiently detailed instruction in oral hygiene (especially for ectopic erupted teeth), and fluoride application. In the early mixed dentition stage, orthodontic evaluation should be obtained in order to achieve optimal timing for initiating orthodontic treatment. The oral surgeon and orthodontist will determine the best timing for an alveolar bone graft and possible orthognathic surgery. Later, if the patient has speech problems or inadequate velum closure, a speech bulb or palatal lift appliance may be needed. If spaces due to congenitally missing incisors can’t be closed by orthodontic treatment, an implant or traditional fixed prosthesis may provide the best function and esthetic result.
Presurgical orthopedic or soft/hard tissue molding of the cleft lip and palate has become the treatment of choice for many craniofacial teams. This treatment modality is used to reduce the soft tissue cleft and facilitate lip repair. It precludes the need for lip adhesion with the attendant operative risks, expense, and potential tissue damage.
History of presurgical orthopedic soft/hard tissue molding
Presurgical orthopedics for the treatment of cleft lip and palate has been in use since the early 1500s, when Franco described the use of an extraoral head cap prior to surgical intervention. In the late 1700s, numerous researchers and surgeons began to experiment with bandages over the prolabium to stimulate muscle retraction with force, compressing the premaxillary region. In 1844 Hullihen used adhesive straps to prepare and close alveolar clefts prior to surgery.7 In 1950, McNeil developed an oral prosthesis, similar to an obturator, to approximate the cleft alveolar segments. He modified his appliance so that he was able to reduce the cleft by reorienting the direction of facial growth.8 Many orthopedic presurgical techniques have evolved.7, 8 Huebener and Liu3 classified the appliances as intraoral, extraoral, surgical, postsurgical, active or passive.
In the early 1980s Latham developed the pin-retained orthopedic appliance to exert a forward force on the posterior segment of unilaterally cleft maxillae. For bilateral clefts he designed a slightly modified appliance to control the posterior width of the maxilla, while retracting the premaxilla with a light constant force by means of a staple and power chain.9
Twenty years ago, Grayson and Cutting introduced the presurgical nasal alveolar molding (PNAM) appliance. This allows surgeons to repair the lip, nose, and gingiva with one surgical procedure. This appliance not only molds the affected intraoral and extraoral structures, but also provides nasal support to mold collapsed nostrils. It improves the position and symmetry of nasal deformities (Figures 1, 2, 3), and has shown significant reduction in the size of the cleft intraorally.
The PNAM appliance was developed as an improvement over the Latham appliance.7, 10 This newer appliance takes advantage of the plasticity—and lack of elasticity—of the neonatal cartilage during an infant’s first two or three months.7, 11, 12
Objectives of Presurgical Nasal Alveolar Molding (PNAM) appliance
The objectives of PNAM therapy for unilateral and bilateral cleft patients are, 1) approximate and align the alveolar segments, 2) correct the alar base and cartilage of the affected nostril, 3) reposition the philtrum, nasal septum, and columella along the midsagittal plane, and, 4) lessen closure tension after lip repair.7, 8, 11, 13 It also improves certain functions, such as swallowing and breathing, through the elevation of the collapsed nostril.
Clinical procedure of PNAM appliance
The PNAM is fabricated from an intraoral impression of the maxilla, which needs to be handled with caution. If the impression is taken in a clinical environment, a small-tip suction device and oxygen mask should be ready. The impression material should have enough tensile strength to prevent impression material breakage and potential swallowing by the infant. A constant neck support should be used during the impression. The base of the molding appliance, made from acrylic resin, is polished and fitted for insertion. Two stabilizing buttons, added to the base of the appliance with a wire core, allow the direction of the buttons to be adjusted. Extraoral tape and denture adhesive paste can be used to increase retention of the appliance. This molding appliance is frequently adjusted by selectively grinding the area into which the alveolar bone segments are supposed to move. These gradual changes result in a more symmetrical maxillary arch.6, 7, 11, 12, 14
The success of the molding appliance is improved by taping together the lip segments across the cleft. The tape produces a controlled movement of the alveolar segments, improves the deviated columella, and moves the affected nostril into a balanced, upright position. The PNAM appliance assists practitioners in meeting the goal of presurgical orthopedics, which is to normalize mid-facial anatomy by reducing some of the forces that frequently cause collapse of the maxillary arch.
Parents are instructed to remove the appliance daily in order to clean any food debris and/or secretions from the appliance. The appliance is coated with fresh denture adhesive and reinserted.
Once the alveolar segment is reduced, one or more nasal stents are added. Each stent consists of a .025 mm stainless steel wire with a coil attached using a retention loop in hard acrylic connected to the labial flange of the molding plate.The extraoral portion of the wire ends in a bulb made from a hard acrylic core covered outside with soft acrylic15 for contact with the affected nasal dome and alar cartilages (Figure 3). The nasal stents provide support and mold the affected nostrils into a more symmetrical shape. The nasal stent is designed to apply selective pressure gradually to either stretch or pull the affected tissues of the nose.
External PNAM appliances increase columellar width, decrease columellar deviation, and increase the height of the affected nostrils, resulting in a more symetrical appearance. Internally they achieve reduced alveolar clefts as well as aligning and approximating the alveolar segments (Figures 5, 6).3, 7, 10, 11, 13
The Advantages and Disadvantages of PNAM appliance
The PNAM appliance offers several unique advantages. One is producing increased symmetry of both the soft and hard tissues. This in turn decreases the number of primary labial and nasal surgeries, which minimizes the extent of scar tissue formation. The molding appliance also serves as an obturator that facilitates the creation of negative pressure during the swallowing process. This increases the amount of formula ingested and shortens the feeding time, resulting in greater feeding efficiency. In addition the tongue can be trained to occupy a better position during both the swallowing phase and resting position. The ability of the PNAM appliance to treat both unilateral (Case 1, Figures 5-15) and bilateral (Case 2, Figures 16-23 below) cleft lip and palate patients clearly demonstrates its advantages (page 35).