Many morphometric features that put adults at risk for OSA/SDB are present during childhood and it is important for sleep specialists to recognize these features and treat them early.

Most lactation (breast-feeding) specialists know very little about obstructive sleep apnea (OSA)/sleep-disordered breathing (SDB), and most sleep specialists know very little about the importance of breast-feeding. It is in the hopes that the second part of this article will help educate both sides to the fact that there is a strong relationship between the specialties, and that both specialties will start working together to help study and prevent the very serious medical condition called OSA/SDB.

There are no ideal treatments for OSA/SDB—all have potential side effects. A tracheostomy, although usually 100% successful, is not a choice most people would prefer. Patients who use continuous positive airway pressure (CPAP) often have problems with compliance. Surgeries do not always solve the challenges of OSA/SDB, and may even make the condition worse. Oral appliances can move teeth and cause malocclusions or create temporomandibular jaw (TMJ) problems.

Christian Guilleminault, MD, cofounder of the Stanford University Sleep Disorders Center, Stanford, Calif, stated at the 2002 American Dental Sleep Medicine Conference in Seattle that prevention is the best form of treatment for OSA/SDB. This author also believes prevention is the key. In order to prevent OSA/SDB, however, one needs to understand some of the factors that affect it. It is important to note that OSA/SDB is not just limited to obese people and there is more to OSA/SDB than the results from a sleep study.

Guilleminault has coauthored articles^1-2 that describe the risk factors of OSA. These factors include a high palate, narrow dental arches, overjet, high body mass index (BMI), and a large neck. If an individual does not have a high BMI or large neck size, then the predictive factors for OSA are a high palate, narrow dental arches, and overjet.

In another article by Guilleminault,³ he states that inherited craniofacial features can be a strong indicator of risk for developing OSA. Genes are factors in facial form; however, many facial forms are influenced by habits.

Kushida et al⁴ stated that abnormal tongue activity is also a predisposing factor for OSA. Some abnormal tongue activity is genetically linked, but is mainly the result of bottle-feeding and excessive noxious habits such as pacifier use, digit sucking, lip sucking, arm sucking, and blanket sucking.⁵

Morphometric features
Anything that contributes to the blockage or collapse of the oral cavity and/or airway space can contribute to OSA/SDB. Factors that can contribute to blockage or collapse include:

• grossly enlarged tonsils and adenoids
• macroglossia
• elongated soft palates and enlarged uvulas
• polyps, tumors, and other abnormal growths
• facial-skeletal growth abnormalities
• central nervous system dysfunction affecting facial muscles
• ankyloglossia (tongue-tie)⁶
• large tori
• improper feeding of infants (using artificial bottles and nipples)
• noxious habits that include pacifier use, arm sucking, lip sucking, blanket sucking, and excessive digit sucking
• drugs or diet⁷

Breast-feeding
Breast-feeding is important for the proper development of the swallowing action of the tongue, shaping of dental arches, and proper alignment of the teeth.^8,9

The tongue contributes to the developmental shaping of the palate9 during its motion across the palate during a swallow. Insert a bottle or pacifier between the tongue and the palate and the tongue cannot reach the palate. The physical contact of the bottle-nipple/pacifier can actually elevate the height of the palate. A vacuum created by strong sucking actions during excessive noxious habits can also increase the height of the palate.9

Figure 1. Adult swallowing pattern.

From a dental or oral cavity developmental perspective, the importance of breast-feeding is for a proper swallowing pattern to be developed. The swallowing pattern developed during infancy extends into adulthood. A proper adult swallowing pattern (Figure 1) is initiated with the tip of the tongue on the maxillary anterior papilla area just behind the maxillary front teeth. The tongue then continues across the hard palate in a peristaltic-like motion pushing either a bolus of food or saliva ahead of the motion. Near the end of the swallow, the tensor palatini muscles fire and open the eustachian tubes. The levator palatini muscles and the tensor palatini muscles elevate and tense the soft palate so that food and water will not escape through the nose. During a normal correct swallow, the tongue should not exert any pressure on any teeth. The tongue should then rest against the anterior portion of the hard palate until the next swallow.

During bottle feeding, a proper swallowing action may not develop and a tongue-thrust may develop instead. Not much muscle coordination is needed during most bottle-feeding, so perioral, facial, and TMJ musculature may not develop properly. Some of the time during bottle-feeding, the infant only needs to squeeze on the nipple to express formula from the bottle. At other times, the infant may have to suck excessively to remove formula from the bottle. Since the hole at the tip of the nipple is not regulated to a standard size, the size of the hole can be quite variable. A nipple with a large hole may gush out an excessive amount of formula that could possibly choke the infant. The infant has to place the tongue at the back of the throat in a protective posture so that too much formula does not go down the throat. If the hole is too small, the infant may have to suck on the nipple excessively to express the formula. As formula is removed, a vacuum can be created inside the bottle. More suction is then needed to remove the formula. The greater the sucking action needed within the mouth, the greater the potential for collapse of the oral cavity.

Figure 2. Adult tongue-thrust.

During bottle-feeding, the position and action of the tongue are different than during breast-feeding. Since most bottle-nipples are firmer than the breast, the tongue gets drawn inside the mouth to protect the bottom side of the tongue from being traumatized by the gum pad.¹⁰ A tongue-thrust (Figure 2, page 55) is most likely to develop when this occurs. The excessive vacuum that may be needed during bottle-feeding and the development of a tongue-thrust are the main contributing factors to the malocclusions that put an individual at risk for OSA/SDB. The above is also true for excessive use of pacifiers, digit sucking, blanket sucking, and arm sucking.5

Related articles
Paunio et al¹¹ found that dummy and digit sucking was strongly associated with malocclusion and found that 35% of 3-year-olds had a malocclusion. Melsen et al¹² found that digit and dummy sucking resulted in increased tendency to tongue-thrust, and tongue-thrusts were related to open bites, cross bites, overjet, and Class II malocclusion. It was concluded that sucking habits influence the etiology of malocclusion. Davis and Bell¹³ demonstrated that there was a strong association (P=>.0006) between exclusive bottle-feeding and malocclusion, and that the relationship did not diminish as the child grew from the primary to permanent dentition.

A study by Farsi et al¹⁴ demonstrated that digit and dummy sucking was the lowest among children who had a good opportunity for breast-feeding and that there was a significant relationship between sucking habits and malocclusion such as Class II malocclusion, increased overjet, and anterior open bites. The principal finding in the study by Labbok and Hendershot¹⁵ was that the longer the duration of breast-feeding, the lower the incidence of malocclusion. The study also found that bottle-feeding leads to a habit of tongue-thrusting, and there was a significant decrease in tongue-thrusting with an increased duration of breast-feeding.

A tongue-thrust is probably the biggest contributor to the development of a malocclusion and to the relapse (failure) of most orthodontic cases. To observe a tongue-thrust, one just has to have a person with a malocclusion close the mouth, then slightly separate the lips, and then have the individual swallow. If the individual has a malocclusion with spaces anywhere in the mouth, one will be able to see the tongue extend into the space(s) during the swallow. Saliva may also ooze between the teeth. During a correct swallow, the tongue should be on the roof of the mouth and the saliva should be forced distally into the throat, not forward between the teeth.

Adults do not form the morphometric characteristics that put them at risk for OSA/SDB overnight. They had those characteristics when they were young, but nobody understood or appreciated the consequences of those characteristics.

In 1996, the American Academy of Pediatric Dentistry (AAPD)¹⁶ stated that 89% of youth, ages 12 to 17, had some occlusal disharmony, and that 16% of youth had such severe handicapping malocclusion that treatment was mandatory. In 1997, Victora et al¹⁷ conducted an epidemiological study, which showed that pacifiers were commonly used by 85% of infants in her study by 1 month of age. She also found that children weaned from breast-feeding early use a pacifier more often than those who were breast-fed longer. The Victora and AAPD findings should be alarming. Is it just by chance that these percentages are so similar? This is extremely significant once one realizes that in prehistoric times, and in nonindustrialized cultures as recently as the 1930s,7 people had minimal malocclusions.

Shepard et al¹⁸ stated that the largest increment of craniofacial development occurs within the first 4 years of life and that 90% of craniofacial development is complete by the age of 12. Since 90% of craniofacial development has occurred by that age, then it is very likely that the morphometric features that put adults at risk for OSA/SDB were probably present at age 12. Addressing and correcting these features early may significantly reduce the medical problems that many children have as a result of undiagnosed OSA or upper airway resistance syndrome. The most important thing in life is one’s ability to breathe. A person’s health is directly related to their ability to breathe oxygen. If a child or an adult cannot breathe well, then their health will be affected in some way.

Most children are not screened or tested for OSA/SDB and therefore are not diagnosed with the condition. The reason for this is that many physicians, especially pediatricians, are still unaware of the relatively new field of OSA/SDB. Conditions such as bed wetting,^19,20 behavioral problems,²¹ and attention deficit hyperactivity disorder²² could possibly be prevented if infant sleep problems were addressed early.

Figure 3. Massive tongue.

Figure 4. Adult tori.

Oral Characteristics of Sleep Apnea
Anything that decreases the normal volume of the oral or nasal cavity can contribute to OSA/SDB. Some factors that can contribute to decreased size include tumors, large tongues, and tori. Large tongues are due to genetics, while tori are due to clenching and bruxing (Figures 3 and 4, page 56). Tongue-based obstructions can be checked by pulling the tongue forward out of the mouth with gauze and then having the person breathe while the tongue is advanced. Those with obstructions at the tongue base can many times immediately note better airflow. Obstructions to nasal airflow can be checked by visual inspection using a nasal spectrum or by blocking one side of the nose while having the patient breathe through the other side. One should also note the shape and collapsibility of the nose.²³

Individuals with long face syndrome (LFS)²⁴ are also at high risk for having OSA/SDB. Although some individuals with LFS have a genetic predisposition for it, many have the disorder because of large tonsils or an obstruction in the airway that forced them to become mouth breathers when they were youngsters. The chronic mouth breathing can then lead to a narrowing or collapse of the face.²⁵

Conclusion
We are seeing just the tip of the iceberg when it comes to the medical expenses associated with OSA/SDB. Most of the morphometric features that put an adult at risk for OSA/SDB are present during early childhood. It is up to health care providers to recognize these features and treat them early. Many of our children are suffering disorders related to airway resistance and poor quality of sleep. By treating early, we, as a society, can have healthier children as well as lowered health care costs. Treatments can be as simple as rapid palatal expansion before the fusion of the midpalatal suture line, removal of massive tonsils, or correction of a Class II malocclusion at the proper growth period. Prevention is the best and cheapest way to treat OSA/SDB. The best prevention is breast-feeding and keeping pacifiers out of the mouths of our children. Breast-feeding is the best form of health care we can give children. It is free to all children. Not only are there nutritional, immunological, and psychological benefits of breast-feeding, there are also the benefits of a better occlusion and a reduced risk of OSA/SDB. All health care providers need to understand the benefits of breast-feeding and need to encourage it as much as possible.

Brian G. Palmer, DDS, is a full-time general dentist in Kansas City, Mo, who has a special interest in the cause, prevention, and treatment of obstructive sleep apnea.

References
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