NASORESPIRATORY CONSIDERATIONS IN ORTHODONTICS

INDEX

◊ HISTORY◊ ANATOMY◊ RESPIRATORY MECHANICS◊ NASAL AIRWAY MECHANICS◊ EVOLUTION OF THE AIRWAY◊ PATHOLOGIES CAUSING CONSTRICTION◊ NASORESPIRATORY FUNCTION AND CRANIOFACIAL GROWTH◊ HEAD POSTURE AND CRANIOFACIAL MORPHOLOGY◊ ADENOIDS◊ RHINITIS◊ OBSTRUCTIVE SLEEP APNOEA◊ DIAGNOSIS◊ TREATMENT

HISTORY

• Angle, 1907, Cl II DI malocclusion is always accompanied and at least in its early stages aggravated, if not caused by mouth breathing due to some form of nasal obstructions.

• Derichsweiler (1956) argued against nasal obstruction being a primary etiologic factor in dentofacial deformity.

• Watson and Colleagues (1968) are also of similar opinion and suggested that when resistance was high mouth opening invariably resulted, but skeletal deformity did not always occur.

• Korkhaus (1960) on the other hand, suggested that maxillary arch form is a primary factor in determining nasal cavity size and hence breathing mode.

• Linder-Aronson (1970) and Tully (1966) described a special facial type “Adenoid facies” as characteristics of persons with enlarged adenoids and mouthbreathers.

• Hunter (1971) did not find a relationship between allergic rhinitis and

malocclusion, but demonstrated that frequency of mouthbreathing increases as nasal airway resistance increases

ANATOMY

• The air way consist of • The nose. • The pharynx.

• the nasopharynx. • The oropharynx.• the laryngopharynx.

• The larynx.• The trachea.• The bronchi and the bronchioles.

EXTERNAL NOSE

• The external nose has a skeletal framework that is partly bony and partly cartilaginous. The bones are the nasal bones, which form the bridge of the nose, and the frontal processes of the maxillae. The cartilages are the superior and inferior nasal cartilages, the septal cartilage, and some small cartilages.

NASAL CAVITYIt extends from the external nares (nostrils) to the posterior nasal apertures, and is subdivided into right and left halves by the nasal septum. Each half has a roof, a floor, and medial and lateral walls. Each half measures about 5 cm in height, 5 to 7 cm in length, and 1.5 cm in width near the floor. The width near the roof is only I to 2 mm. The roof is about 7 cm long and 2 mm wide. is formed by the nasal part of the frontal bone,nasal bone, and the nasal cartilages.

NASAL SEPTUM

It is median osteocartilaginous partition between the two halves of the nasal cavity. On each side it is covered by mucous membrane and forms the medial wall of both nasal cavities

PHARYNX

• The pharynx is a wide muscular tube, situated behind the nose, the mouth and the larynx.. The upper part of the pharynx transmits only air, the lower part (below the inlet of the larnyx), only food, but the middle part is a common passage for both air and food, (but only one at a time).

NASOPHARYNX

• This is the upper part of the pharynx situated behind the nose, and above the lower border of the soft palate. It resembles the nose structurally as well as functionally.

OROPHARYNX

• This is the middle part of the pharynx situated behind the oral cavity. Above, it communicates with the nasopharynx through the pharyngeal isthmus. In front, it communicates with the oral cavity through the oropharyngeal isthmus . Below, it opens into the laryngopharynx at the level of the upper border of the epiglottis. Behind, it is supported by the body of the axis vertebra and the upper part of the body of the third cervical vertebra. Its lateral wall presents the tonsil which lies in the tonsillar fossa.

RESPIRATORY MECHANICS

The lungs fill the thoracic cavity, and its outer surface (visceral pleura) is in intimate contact with the inner surface of the thoracic cavity . The 2 pleural layers are in apposition, separated only by a thin film of fluid which enables the lungs to slide freely within the cavity. Whenever the chest cage enlarges the lungs also enlarge.

At the end of expiration, when the respiratory muscles are relaxed, pressure within the lungs is atmospheric and there is no airflow. This is the resting position. Both the lungs and the chest wall contains considerable elastic tissue, and at resting position these pull with equal forces but in opposite directions, creating a balance of elastic forces.

When contraction of the diaphragm and intercostal muscles occurs during inspiration, the volume of the thoracic cage enlarges and the elastic forces of the two units change. When the diaphragm contracts, its dome moves downwards into the abdomen, thus enlarging the thoracic cavity. Simultaneously, the inspiratory muscles move the rib cage upward and outward, also increase the volume of the thoracic cavity. This enlarges the volume of air within the lungs, pressure falls below atmospheric and air is drawn into the expanding lungs.

While inspiration is an active process involving muscles, normal expiration is a passive event. As the thorax and lungs spring back to their original sizes, pulmonary air becomes temporarily compressed so that its pressure exceeds atmospheric and air flows from the lungs to the outside.

Nasal Airway Mechanics

The nose is now recognized as being the major site of inspiratory airflow resistance to normal breathing in humans. The funnel-shaped nasal vestibule leads from the external nostril to the nasal valve region which constitutes the major airflow resistance segment of the respiratory airways. The cross-sectional area of only approximately 30 mm2 is the smallest cross-section of the whole respiratory tract.

Control of nasal airflow within the valve region is complex, and is influenced by the rigidity of the aperture, the actions of dilator muscles, as well as the degree of mucosal congestion within the nasal passages. Consequently, the human nose counts for about 40-60% of the total respiratory resistance in normal subjects at rest. .

A typical feature of nasal airflow resistance is that the resistance of the two separate nasal cavities often differs markedly. There is a spontaneous reciprocating cycle of nasal congestion and decongestion that is well recognized and has been called the nasal cycle. During exercise, there is a decrease in nasal resistance at any given flow due to vasoconstriction of the nasal mucosa. The supine posture is associated with a slight increased in nasal resistance compared with the upright posture. In addition, during sleep there is an additional small rise in nasal resistance values.

The alae nasi muscles are important for stabilizing the nasal valve and vestibule region, and act to prevent inspiratory collapse of the valve region, particularly during exercise and hyperventilation. Although nasal resistance values tend to be increased in obstructive sleep apnoea (OSA) patients, the role of nasal resistance in the genesis, maintenance or severity of OSA remains unclear. Nevertheless, diseases leading to nasal obstruction may cause larger pharyngeal collapsing pressures during inspiration, thus promoting pharyngeal collapse and obstruction in OSA patients.

EVOLUTION OF THE AIRWAY

The human pharynx is unique in the animal kingdom. Postmortem dissections on many types of mammals reveal that the epiglottis extends up behind the soft palate to directly join the larynx to the nasopharynx This provides a firm, uninterrupted air channel from the external nares, through the nasal cavities and nasopharynx, past the larynx, and down to the trachea and lungs. As such, no pharyngeal muscles were designed specifically to maintain upper-airway patency, since none were necessary. In addition, the tongue is located anteriorly, entirely within the oral cavity and separate from the pharynx, so it cannot impact the pharyngeal space at any time. This allows the animal to eat and breathe at the same time, preserving the sense of smell so necessary for survival.

EVOLUTION OF THE AIRWAY

Over time, however, human evolution has given rise to the separation of the epiglottis and the soft palate to create an upper airway that is longer and more flexible. This separation allows the tongue to reside partially within the pharynx to create a soft-walled oropharynx unique to modern humans, which provides a resonating chamber for refined vocalizations. Unfortunately, it also provides the opportunity for sleep-induced collapse of the upper airway. To complicate matters, continuing evolution of our species resulted in an erect posture that brought the facial skeleton to lie below the frontal region of the braincase, rather than in front of it as in most quadruped animals. This facial migration, known as klinorynchy, constricts the available subcranial space to the extent that a change in pharyngeal and laryngeal morphology is necessitated.

It is interesting to note at this point that the pharyngeal anatomy of the human newborn and very young infants closely approximates the anatomy of the upper airway of non-human mammals.Specifically, the epiglottis and soft palate overlap and the tongue is completely anterior to the airway. No oropharynx, per se, is present. This allows for the simultaneous suckling of milk and breathing. By approximately 18 months of age, however, the laryngeal complex has migrated caudally, giving rise to the oropharynx, the ability to vocalize, and the concomitant predisposition to sleep-induced upper-airway collapse.

PATHOLOGIES CAUSING CONSTRICTION

Nose

• Choanal atresia,nasal septal deviation, hypertrophy of turbinates, Polyposis, Dermoid cyst, Tumors.

Nasopharynx

• Adenoidal hypertrophy ,Stenosis,Pharyngeal flap for cleft palate,Tumors.

Mouth and oropharynx

• Hypertrophied tonsils, Macroglossia , Micrognathia, Temporomandibular joint ankylosis. Larynx

• Tracheal atresia,Intrinsic tracheal lesions,Extrinsic compression (goiter),Laryngeal and tracheal webs,Kimura disease (Okami, 2003)

NASORESPIRATORY FUNCTION AND CRANIOFACIAL GROWTH It is assumed that nasorespiratory function can exert a dramatic effect upon

the development of the dentofacial complex. Specifically, it has been stated that chronic nasal obstruction leads to mouth breathing, which causes altered tongue and mandibular positions. If this occurs during a period of active growth, the outcome is development of the "adenoid facies" .

In 1872, C.V. Tomes coined the term “Adenoid Facies” or ‘Long Face

Syndrome’ to describe the dentofacial changes associated with chronic nasal airway obstruction.Any condition that causes nasal obstruction could lead to this typical facial morphology. This syndrome is characterized by an increased LAFH,increased dentoalveolar height,gummy smile,high arched palate ,steep mandibular plane,excess incisal show,anterior marginal gingivitis and long-standing nasal obstruction may lead to "disuse atrophy" of the lower lateral cartilages , resulting in as slit-like external nose with a narrow nasal vault.

The "long face syndrome" is often associated with crossbite, tension nose, and a Class-II (mandibular retrognathic) occlusion. Another group of children develop Class-III occlusion (mandibular prognathic) occlusion which may be due to anterior displacement of the tongue due to tonsillar hypertrophy. This creates a pressure affects on the lingual aspect of the lower dental arch, causing a prognathic mandible and undererupted lower teeth.

Children who have hypertrophied adenoids, tonsils and inferior turbinates develop long face syndrome 30 percent of the time. In contrast, children with normal respiratory airways develop long face syndrome 2 percent of the time.

3 theories have been proposed regarding the effects of mouth breathing on the facial form & dentition.

A) Compression according to Norlund (1918) constriction of the maxillary arch is related to the absence of lateral pressure of the tongue against the palate. This occurs in response to nasal obstruction wherein the patient tries to breath through the mouth instead of the nose. Therefore the tongue drops down leading to increase in the buccal musculature force thereby causing constriction of the arch. This effect is further enhanced by a pressure differential across the hard palate in the absence of nasal airflow leading to a narrow & high arched palate.

B) Theory of Inactivity :- according to which there is reduced growth of the nasal cavity, due to its inactivity, as suggested by Korner (1891) and Bentzen (1903).

C) Air pressure theory :- this theory proposed by Kantorowicz (1916) & James & Hastings (1932) states that when the breathing of a person changes from nasal to mouth, it causes the normal negative pressure in the anteriorly sealed oral cavity to be lost & thereby the palate does not descend down with the growth of the maxilla.

• Linder Aronson did a 5 yr follow up study of children undergone adenoidectomies to clear obstructed nasal passages.

• Purpose of the study was to evaluate the changes seen in U/L incisal inclination , Upper arch width, Sagittal depth of nasopharynx., Anterior facial height.and Inclination of the maxilla to mandible after the shift from oral to nasal breathing .Results showed that the values became normal after five years with most of the changes occurring in the first year after surgery.

• Harvold and associates have shown that obstruction of the nares in monkeys is followed by the recruitment of muscles to lower the mandible and spread the lips to establish an oral airway.All experimental animals with their nares blocked kept their mouth open continuesly.in most animals the upper lip gradually developed a notch in the middle.Tounge became more narrow and pointed.Cephalometric finding showed increased gonial angle

• The experimens demonstrated that the recruitment of the orofacial muscles for respirationhad significant effect on muscle development.This in turn,changed the morphology of the upper lip,the tongue and the oro pharyngeal port

• Robert M. Rubin ( AJO 1980 ) conducted studies on mode of respiration and facial growth, and stated that spatial relationship of mandible to craniomaxillary complex is influenced by function of muscular elevators of mandible. One factor acting on the elevators of the mandible is the rest position of the mandible, which may be influenced by the patient’s mode of respiration. Obstruction of the nasal airway is followed by the lowering of the mandible to establish an airway.

• Peter S Vig ( AJO 1981 ) studied the relationship between facial morphology and nasal respiration. Concluded that lip incompetence is not synonymous with mouth breathing. Although long-faced subjects as a group had a higher mean value of nasal resistance, the range of variation was so great as to prelude the diagnosis of nasal obstruction from an

assessment of facial morphology

• Behlfelt et al (EJO 1989) studied the dentition in children with enlarged tonsils compared to control group and concluded that children with enlarged tonsils have more retroclined lower incisors, more anteriorly positioned upper incisors, small overbite. Large overjet shorter lower dental arches, narrower upper arches and an increased frequency of lateral cross bite, obstruction of oropharynx by enlarged tonsils is responsible for functional and/or morphological disorders causing an open posture of the mouth, a lowered anterior posture of the tongue and a low position of the hyoid bone are thought to be associated with the differences in the dentition between the two groups.

• Tu lin Arun, et al ( AO 2003 ) studied on vertical growth changes after adenoidectomy and concluded that when compared with the control group, the adenoidectomy group showed a more vertically directed growth pattern.

• Tetsuro Yamada, D (AJO 1997) studied on influences of nasal respiratory obstruction on craniofacial growth in young macaca fuscata monkeys,this study was conducted to investigate the influences of artificial nasal respiratory obstruction on craniofacial growth

• . Nasopharyngeal respiratory obstruction was associated with downward and backward rotation of the mandible, upward and backward growth of the condyle, divergent gonial angle ,anterior open bite, and spaced dental arch in the lower anterior region.

• Solow, Siersbaek-Nielsen, and Greve ( AJO 1984) studied associations between airway adequacy, head posture, and craniofacial morphology, and found that obstructed nasopharyngeal airways were, on the average, seen in connection with a large craniocervical angle and with small mandibular dimensions, mandibular retrognathism, a large mandibular inclination and retroclination of the upper incisors.

• Pushker ( AJO 2001) had done study on pharyngeal airway space changes after counterclockwise rotation of the maxillomandibular complex to evaluate the effects of double-jaw surgery with counterclockwise rotation of the maxillomandibular complex on the pharyngeal airway space and velopharyngeal anatomy in patients with high occlusal plane facial morphology and concluded that the counterclockwise rotation of the maxillomandibular complex may cause a significantly greater reduction in the PAS than is observed with non counterclockwise movements when mandibular setback is performed.

 Shiva Shanker et al (Semi. Orthod. March 2004) performed a longitudinal study for a period of 4 years in growing children to determine the upper respiratory parameters & dentofacial morphology & their interrelationships.

Modified simultaneous nasal & oral Respirometric technique (SNORT) & post rhinomanometry were performed for the children.

The dentofacial variables measured were, a)     Lower face height % = LFH / TFHb)     Facial Index = Facial height / Facial widthc)      Overbited)     Palatal arch widthThey concluded in their study that – children switch

between oral & nasal respiratory mode & Respiratory mode had no relationship to Ethnicity, Gender / dentofacial morphology.

Ricketts in 1979 stated that when there is a lack of function in the nose, there can be a growth inhibition.

Another group of researchers denies a significant

relationship between facial morphology and mode of breathing. Kingsley was among the first to consider the V-shaped maxillary arch and deep palate a congenital trait not related to mouth breathing.

In a subjective evaluation of 1,033 children, Humphrey and Leighton reported an approximately equal distribution of malocclusions in nose and mouth breathers. They noted that, of those children who kept their mouths open while breathing, almost half respired nasally.

Gwynne-Evans and Ballard also subjectively evaluated the relationship between facial morphology and breathing conditions over a period of 15 years. They reported that orofacial morphology remains constant during growth, regardless of breathing patterns. They also stated that ''mouth breathing does not produce deformities of the jaws and malocclusions and does not result in the development of the adenoidal facies."

Leech examined the relationship between lip competence and mode of breathing in subjects undergoing evaluation in a research clinic for upper respiratory disease and found that fewer than one third of the lip-incompetent persons were mouth breathers. Thus, many theories have been proposed and much confusion remains regarding the relationship between nasorespiratory function and dentofacial morphology.

HEAD POSTURE AND CRANIOFACIAL MORPHOLOGY

A recent trend for research has been to focus on the possible role of extrinsic factors that are able to affect cranial posture in a manner that could be associated with aspects of specific malocclusions In this regard, extension and flexion of the head away from the natural head position has been observed to be associated with certain morphologic patterns Accordingly, adults who display habitually extended cranial positions also exhiibit, among other specific facial features, greater lower facial heights, obtuse gonial angles, and a relative manndibular retrognathism.

A functional relationship appears to exist between the temporomandibular and craniocervical regions, and head movements apparently are an integral part of natural jaw opening and closing. Functional jaw movements comprise concomitant mandibular and head-neck movements, which involve the temporomandibular, the atlantooccipital, and the cervical spine joints, caused by jointly activating the jaw and neck muscles

Although the posture of the head may be related primarily to efforts expended in resisting the force of gravity, nevertheless the physiologic requirements associated with respiration, deglutition, sight, balance, and hearing also must affect cranial deportment.

Thurow demonstrated how the hyoid bone is pulled forward by passive stretch of the suprahyoid muscles when the head is extended. In this respect the midline raphe of the musculus mylohyoideus consists largely of fibrous tissue with little scope for stretching Such cranial extension is seen commonly in mouth breathers, and this postural change could represent an important component for nasal airway inadequacy.

In this study, the induced bite opening caused a downward displacement of the mandible, thereby releasing the tension on the suprahyoid muscles. One postulation is that the hyoid bone, when deprived of the upward and anterior pull of the suprahyoid muscles, would move posteriorly and reduce the pharyngeal airvvay. The head would extend in a compensatory movement to pull the hyoid bone forward via the resultant increase in tension of the mylohyoid raphe.

The relationship between head posture and craniofacial morphology was emphasized by Schwarz , who found that extension of the head in relation to the body, particularly during sleep, led to distal displacement of the mandible and the development of Class II malocclusion Bjork ('55, '60, '61) noticed that individuals with a flattened cranial base and a retrognathic facial type carried their head in an extended position, while those with a marked bend of the cranial base and a prognathic facial type carried their headin a lower position. Bench ('63) in a radiographic study of the growth of the cervical vertebrae noted a tendency for the neck to be curved in subjects with square faces, and straight with a long cervical column in subjects with long faces.

A systematic analysis of the correlations between craniofacial morphology and the positional relationship of the head to the true vertical and to the cervical column was carried out by Solow and Tallgren ('76). They found that of the postural variables, the craniocervical angulation showed the most comprehensive correlation with craniofacial morphology, i.e., the position of the head in relation to the cervical column seemed to be more closely related to craniofacial form than the position of the head to the true vertical.

The correlations indicated that, on the average, extension of the head relative to the cervical column was seen in connection with large anterior and small posterior facial heights, small anteroposterior craniofacial dimensions, large inclination of the mandible relative to the anterior cranial base and to the palatal plane, facial retrognathism, a large cranial base angle, and a small nasopharyngeal space.

The findings regarding the relationship between craniocervical angulation and craniofacial morphology were confirmed by Thompson Posnick ('78). Solow and Tallgren ('76) further observed that differences in craniofacial morphology between subjects with large and small craniocervical angulations were remarkably similar to those between subjects with large and small mandibular plane inclinations. A direct comparison showed that the average craniofacial morphology of a group of subjects who had a large craniocervical angulation resembled that of a group of subjects who had a large mandibular plane inclination .

Similarly, the craniofacial morphology of a group of subjects characterized by a small craniocervical angulation was very like that seen in a group of subjects characterized by a small mandibular plane inclination . This suggests that the factors responsible for the postural differences may also be responsible for differences in mandibular plane inclination and facial type. A similar relationship between facial type and craniocervical angulation was reported by Opdebeek and co-workers ('78).

Hypothesis of soft tissue stretching(Solow and Kreiborg `77)-An extension of the head in relation to the cervical column would entail the passive stretching of the facial soft tissue layer draping theface and neck.The effect of this would be slight backward and downward forces exerted by the soft tissue layer on the facial skeleton thereby restraining the forward and increasing the downward component of the maxillary and mandibular growth relative to the cranial base.

PROPOSED SEQUENCE OF EVENTS Based on numerous studies over the past century, a plausible

sequence of events can be pieced together as described by Principato . Long standing nasal obstruction appears to affect craniofacial morphology during periods of rapid facial growth in genetically susceptible children with narrow facial pattern. A change from nasal to oral respiration likely occurs when nasal resistance reaches two to three times normal. Since nasal resistance increases in the supine position, borderline airways may convert to oral respiration at night. During oral respiration, the mandible rotates to a more open position and the tongue assumes a lower position in the mouth and is no longer in contact with the palate. Prolonged periods of oral respiration lead to extensive eruption of the posterior molars, in response to a lack of surface contact.

These overerupted teeth exert a downward vector of force on the mandible, causing the lower jaw to rotate down and back in a "clockwise" direction. . Because of the backward mandible rotation, retrognathia and open bite deformities are common. Tongue posture changes with chronic oral respiration can also affect the teeth. With a lowered tongue position, the lateral expansile forces of the tongue on the palate are lost, and the unopposed medial forces of the buccinator and masseter muscles lead to a narrow, high arched palate in susceptible children. The incomplete lateral expansion of the maxilla often leads to a unilateral or posterior crossbite.

•

ADENOIDS

Adenoids are on the posterior nasopharyngeal wall posterior to the nasal cavity . They develop from a subepithelial infiltration of lymphocytes in the 16th week of gestation. They are a component of the Waldeyer ring of lymphoid tissue, which is a ring of lymphoid tissue in the oropharynx and nasopharynx that consists mainly of the adenoids, the palatine tonsils, and the lingual tonsils.

Adenoids are present at birth and then begin to enlarge. They, along

with the tonsils, continue to grow until individuals are aged 5-7 years. The adenoids usually become symptomatic, with snoring, nasal airway obstruction, and obstructed breathing during sleep, when children are aged approximately 18-24 months. By the time children reach school age, the adenoids normally begin to shrink, and, by the time children reach preteen or teenage years, the adenoids are usually small enough for the child to become asymptomatic.

The purpose of the tonsils and adenoids

The tonsils and adenoids are thought to assist the body in its defense against incoming bacteria and viruses by helping the body to form antibodies. However, this function may only be important during the first year of life. In fact, there is no evidence to support a significant role of the tonsils and adenoids in immunity.

Enlarged adenoids can cause nasal airway obstruction, with clinical symptoms of nasal congestion, snoring, and breathing through the mouth, by physically blocking the back of the nose. Symptoms of nasal airway obstruction may overlap with chronic sinusitis symptoms, and the physical obstruction may add to sinusitis itself by blocking normal nasal flow posteriorly, resulting in a stasis of secretions and an obstruction in the sinus outflow tract.

Often, enlarged adenoids (with the tonsils) can obstruct breathing patterns in children and can cause obstructive breathing, including apneas, at night. Obstruction is based on their size alone. However, when enlarged, the adenoids may have a chronic infection

Rhinitis

Introduction

Rhinitis means inflammation of the lining of the nose. The mucous membrane that lines the nose becomes inflamed, causing swelling and blocking the airflow. Rhinitis also causes over activity of the glands in the mucous membrane, causing excessive mucus production and a watery discharge.

Rhinitis is a symptom of the common cold and of hay fever (allergic rhinitis). Hay fever is an allergy to grass, weed and tree pollens, moulds, hair, feathers, skin scales (dander), house mites, house dust or other airborne substances. It causes sneezing, stuffiness and a watery discharge from the nose.

There are several varieties of rhinitus:

Vasomotor rhinitis happens when the nerves that control the blood vessels supplying the mucous membrane are disturbed. The membrane becomes over-sensitive to hormonal, climate or psychological changes, and causes sneezing and a watery discharge.  Vasomotor rhinitis is an intermittent condition, meaning that it can come and go.

Hypertrophic rhinitis happens when there has been repeated or long-term inflammation of the mucous membrane.  The lining of the nose thickens, causing a feeling of stuffiness that dosent go away.

Atrophic rhinitis happens when the mucous membrane shrinks, usually as a result of sarcoidosis, tuberculosis or nose surgery (rhinoplasty). The symptoms are dryness, crusting and loss of the sense of smell.

Symptoms

The most common symptoms are: • sneezing, • blocked or stuffy nose, • runny nose (rhinorrhoea), and • itchy nose, throat and eyes.• Often, a person with rhinitis my also have hay fever, asthma

or eczema. Asthma and eczema may start or become much worse in the summer or when the pollen count is high.

 Causes

• Rhinitis due to the common cold is caused by cold viruses and secondary infection with bacteria.

OBSTRUCTIVE SLEEP APNOEA • OSA is a common sleep disorder charecterised by repetitive partial or

complete ceaastion of air flow , associated with oxyhemoglobin desaturation and increased effort to breath.

• Middle age obese men are at particular risk but its also seen in women and young children.

• The human pharynx is unique in the animal kingdom in that it is predisposed to collapse during sleep. In each and every one of us, the upper airway tends to diminish in size and shape to some degree from the relaxing influence of our nocturnal slumber. Most of us, fortunately, manage to breathe silently and effectively despite this ominous challenge to our well-being. This is not so for millions of others, however. Sleep-disordered breathing (snoring and obstructive sleep apnea) affects tens of millions of people worldwide.

On the most basic of levels, the human organism has but three critical needs for survival: eating, sleeping, and breathing. For those who suffering from sleep-disordered breathing (SDB), two out of three of these requirements are in jeopardy every time their head hits the pillow. As sleeping and breathing are compromised night after night for years on end, the most recent research demonstrates that they are at greater risk for hypertension, heart attack, stroke, depression, and diabetes.

it has been shown that patients with OSA are involved in traffic accidents two to three times more often than the general population and are at increased risk for injury in the workplace.

The human pharynx is intimately involved with swallowing, breathing, and speaking; hence, it is called upon to be alternately stiff or flexible depending on the task at hand. The tendency, during sleep, for the upper airway to partially collapse (as in the case of snoring) or to completely obstruct (as with OSA) is multifactorial. Upper-airway patency is a delicate balancing act pitting pharyngeal anatomy and baseline muscle tone against the negative pressures created upon inhalation. During waking hours, patency is easily maintained.

However, with the relaxing influence of sleep and the gravitational effects of the supine position, maintaining a clear airway becomes a titanic struggle for many people. Multiple stresses arise from intermittent airway occlusion, which include repetitive oxygen desaturation, carbon dioxide retention, and disrupted sleep from the arousals secondary to these blood gas discrepancies. As such, there are strong associations between OSA and the risk for cardiovascular disease and metabolic dysfunction.

CLINICAL SYMPTOMS

during sleep• Snoring.• Abnormal motor activity during sleep.• Nocturnal sleep disruption.• Chocking during sleep.• Esophageal reflex.• Nocturia and nocturnal enuresis.• Heavy sweaeing at night.

Daytime symptoms• Excessive daytime sleepiness EDS.• By product of EDS. • Hypnagogic hallucinations.• Changes in personality.• Sexual problems.• Headaches.• Loss of hearing.

Treatment modalities for OSA and snoring at the present time most typically include nasal continuous positive airway pressure (CPAP), oral appliances, and adjunctive measures such as weight loss, medication, avoidance of sedating medication, and body positioning. Surgery options include soft palate surgery such as uvulopalatopharyngoplasty (UPPP) or laser-assisted uvulopalatoplasty (LAUP), radiofrequency (RF) tissue ablation, nasal surgery, genioglossus tongue advancement, and mandibular advancement surgery. .Oral appliance treatment includes, in order of decreasing usage, adjustable and nonadjustable mandibular posturing devices, anterior tongue repositioners, and soft palate or uvulalifting devices. An appliance that advances the tongue, or tongue and mandible together with adjacent soft tissue, increases the posterior airway space, increases the activity of the genioglossal and lateral pterygoid muscles and effects a stretch induction of the pharyngeal motor system.

Mandibular advancement devices also alter position of the hyoid and modify the hypopharyngeal airway space. Soft palate or uvula lifters reduce soft tissue vibrations that result in snoring. With respect to the many variations of appliance designs, it is not possible to predict what device will be most effective for a particular patient. In 1934, Pierre Robin first described the concept of advancing the mandible with a monoblock functional appliance to treat airway obstruction in infants with micrognathia. 1985 that Meier-Ewert and coworkersl described an intraoral protraction device for the treatment of sleep apnea.

CPAP therapy is based on counteracting the negative airway pressure during inspiration, and hypoglossal nerve stimulation was suggested to enhance pharyngeal dilator muscle contraction. Other procedures such as uvulopalatopharyngoplasty (UPPP), and mandibular advancement (either surgical or with a mandibular advancement oral appliance) are based on the principle of pharyngeal enlargement to reduce the degree.of negative intrapharyngeal pressure during inspiration. The translation of these basic concepts into realized therapeutic benefits does not occur consistently, especially in the arena of surgical management.

Orthodontic Diagnosis (JCO 2005)

Although the physician is the health professional responsible for the diagnosis of nasopharyngeal obstruction, the orthodontist can contribute through the use of lateral cephalograms and panoramic x-rays. Regular contact with the patient also allows constant evaluation of the patient's treatment needs and facial growth.

The cephalogram can reveal many obstructive processes in the nasopharynx, including hypertrophy of the nasal or inferior turbinates, maxillary sinus radiopacity or cystic lesions, hypertrophy of the adenoids or tonsils, and the status of the nasopharyngeal airway orthodontist can associate the information obtained from the cephalogram with a good clinical questionnaire. And clinically can evaluate the color, volume, and texture of the mucosa in the front of the nasal cavity, he or she can suggest an initial diagnosis of allergic rhinitis or chronic hypertrophic rhinitis with associated hypertrophy of the nasal turbinates. The diagnosis can then be confirmed or overruled by the otorhinolaryngologist.

Special attention must be paid to the caudal portion of the inferior turbinate, because hypertrophy of this turbinate can obstruct the posterior nasal cavity and impede normal nasal breathing. The lateral cephalogram can also be useful in an analysis of the paranasal sinuses, especially the maxillary sinuses. Sinusitis is suggested when radiopacity is observed. A valid diagnostic agreement between endoscopic and radiographic findings has been found in observing the severity of adenoid hypertrophy and, in particular, the patency of the nasopharyngeal space. The panoramic x-ray can indicate an initial diagnosis of, for example, an anterior septal deviation This may be corroborated in clinical examination simply by lifting the tip of the nose with the fingers A more accurate evaluation can then be made by the otorhinolaryngologist with anterior rhinoscopy.

The panoramic x-ray can also reveal the severity of hypertrophy of the inferior and middle nasal turbinates in the frontal region . Such hypertrophy can be a consequence of chronic hypertrophic rhinitis, medicational rhinitis, or a compensatory hypertrophy, as with a deviated septum. The otorhinolaryngologist can perform a nasopharyngeal video endoscopy to validate the initial diagnosis suggested by the orthodontist.

DIAGNOSIS

• Proper diagnosis of airway could be made with the help of,• Thorough clinical examination,• Investigations

– Radiographs,– Fiberoptic Rhinoscopy,– Rhinostereoscopy– CT & MRI– Polysomnography

• Clinical examination:• A complete examination of the head and neck is performed.• Resting mouth position is noted.• "Adenoid facies" is characterized by an open mouth, dull facial

appearance, and short upper lip. • Other craniofacial anomalies may be associated with these symptoms

including cleft palate, Down syndrome, etc. • Tonsillar hypertrophy, macroglossia and oropharyngeal masses should

be evaluated • The nasal cavity should be inspected for the presence of secretions,

edema and erythema of the nasal mucosa .

• The ears should be evaluated as otitis media certainly is associated with nasal obstruction problems.

• Bony nasal anomalies, external masses, pits, etc. should be evaluated.

• Evaluation of the voice quality includes as assessment of nasality and clarity.

Radiographs:

• Panoromic radiographs – to depict the nasal septum & the nasal cavities.

• Lateral Cephalograms - to eavluate the airway.

• Analysis used are,– Cephalometric Analysis by Brian preston et al (Semi orthod March 2004)– Airway Analysis by McNamara.

• Cephalometric Analysis by Brian• Anatomically the skeletal limits of Nasopharynx

• Anteriorly :- by the bony structures constituting the choanal openings which are the dorsal borders or the choanal crest of the vomer.

• Superoposteriorly :- the pharyngeal surface of the body of the sphenoid bone & of the basilar part of the occipital bone.

• Posteriorly :- the cranial half of the anterior surface of the anterior arch of the atlas.

• Caudally :- the nasopharynx is defined osteologically by a straight line that joins the posterior nasal spine to the most anterior point AA on the anterior arch of the atlas.

DISADVANTAGES:

1.There is the geometric limitation that a cephalogram produces only a two-dimensional representation of the space involved.

2.The nasal airway is a convoluted and anatomically irregular structure and by superimposition and lack of soft-tissue detail this is obscured on traditional lateral or frontal cephalograms.

Airway Analysis by McNamara:

• McNamara has divided the airway analysis into two, Upper & Lower Airway analysis.

• Upper airway measurement:

• Upper pharyngeal width is measured form a point form the posterior outline of the soft palate to a closest point on the pharyngeal wall. The average width is 15-20 mm.

• If the width is 2mm or less than the normal, it may indicate airway impairement

Lower airway measurement:

• Lower pharyngeal width is measured from the point of intersection of posterior border of the tongue & the inferior border of the mandible to the closest point on the posterior pharyngeal wall.

• The average width is 11-14 mm independent of age. If the width is greater than the average, it’s suggestive of a possible anterior positioning of the tongue which may be due to a Habitual posture / due to tonsillar enlargement.

Fiberoptic rhinoscopy It is the insertion of a flexible telescope into the nasal cavity

which allows the detailed visualization of the posterior two thirds of the nose which may not be visible with a nasal speculum inserted into the anterior nares.

Disadvantages:Structural / mucosal displacement of medial / lateral wall of

the nasal valve may not be detected by this method.

Rhinostereoscopy : uses a precise surgical microscope to make direct and noninvasive topographic measurements of the nasal mucosa.

Video nasopharyngeal endoscopy: allows direct visualization and dynamic evaluation of the nasopharynx, including details such as color, texture, and volume.

These images can also be recorded on videotape or in a digital format.Daniel (AJO 2001), evaluated the degree of diagnostic reproducibility

between lateral cephalometric radiography and nasopharyngeal videoendoscopy. He found that lateral cephalometric radiography appears to be sufficiently reproducible for diagnosing hypertrophy of the middle and inferior turbinates and of the region caudal to the inferior turbinate.

Nasopharyngeal videoendoscopy is sufficiently reproducible for diagnosing anterior and posterior septal deviation and hypertrophy of the inferior and middle turbinates & most suitable for diagnosing diverse obstructions of nasopharyngeal origin, but its ability to diagnose rhinitis is limited.

ASSESSMENT OF NASAL AIR FLOW AND RESISTANCE

Measurements include,

Nasal Peak Flow:

less expensive, easy to perform. The flow measurements correlate well with measurements of resistance & are useful for detecting large changes in the nasal patency of each subject.

This technique involves measuring the peak inspiratory nasal airflow with a modified peak flow device (eg nasal inspiratory flowmeter;pneumotachograph).

As the air flows across the flowmeter the pressure drops and is recorded by the tranducer.

Rhinomanometry

Rhinomanometry is well established as a useful clinical method for objective assessment of nasal patency. Nasal resistance to airflow is calculated from measurements of nasal airflow and transnasal pressure. In 1983, standardisation of rhinomanometry was established and accepted worldwide The nasal resistance is calculated from the measurement of the nasal airflow at a fixed transnasal pressure point.

Three types of rhinomanometry can be used: active anterior

rhinomanometry (AAR), active posterior rhinomanometry (APR), and passive anterior rhinomanometry (PAR).

AAR uses a face-mask and one nostril is sealed off with adhesive tape. A hard plastic tube is passed through this tape to measure the nasopharyngeal pressure. It is a dynamic test that studies nasal ventilation, showing the nature of the air stream and a difference in the shape of the inspiratory and expiratory limbs of the individual nasal cavity. This method is well standardised and it is the most common and accurate method for clinical use. The major disadvantage of this method is that it cannot be performed in the presence of a septal perforation or a complete unilateral nasal blockage.

 

B) Acoustic rhinometry

In contrast, acoustic rhinometry does not measure airflow parameters but explores the geometry of the nasal cavity. The principle of acoustic rhinometry is that an audible sound (150 - 10,000 Hz), propagated in a tube, is reflected by local changes in acoustic impedance This method provides estimates of cross-sectional endonasal areas and the endonasal volume. It helps to define objectively the structural and mucosal components of the nasal passage. Since its introduction, there has been an explosion of research using this tool. Due to the rapid acquisition of data that can be completed in a minute, it has become a valuable clinical and research tool. Patient tolerance is excellent, even in children.

Advantages:

It is generally easy to perform, is noninvasive, and does not require patient cooperation like many of the other evaluation procedures.

It produces an image that reflects variations in the cross-sectional

dimensions of the nasal cavity and closely approximates nasal cavity volume and minimal cross-sectional area.

CT

CT scanning produces excellent resolution of images to evaluate both the soft tissue and the osseous structures of the pharynx-larynx complex. It has the advantage of producing axial and coronal cuts. .

The advantages of CT scanning are its wide availability and the quickness with which newer scanners can perform studies. Volumetric and 3-dimensional reconstructions of the airway and other peripharyngeal structures are possible. The study is performed in the supine position.

Disadvantages of the study are that radiation is involved, limiting the number of studies that can be performed. CT scanning is also relatively expensive.

Magnetic resonance imaging

MRI provides a detailed view of the fat and soft tissue of the pharyngeal walls and its relation with the airway. Obtaining sagittal, coronal, and axial images, as well as 3-dimensional reconstructions, is also possible. Measurements of the different structures and their volume are possible. It has the advantage of being radiation free, thus making performance of several studies possible.

Although the noise and the cumbersome design of the machine makes sleeping in it difficult, MRI has been used during sleep to study the effects of continuous positive airway pressure (CPAP) therapy. In addition, performing dynamic studies is possible because of faster equipment.

MRI is beginning to have a role in the evaluation of patients before and

after surgeries such as uvulopalatopharyngoplasty, resection of tongue base, or geniohyoid muscle surgery. MRI is an expensive study, especially with the newer technologies, making its price the real limit to the number of studies that can be performed.

TREATMENT

Suggested remedies include surgical removal of adenoids, turbinectomy, and correction of septal deviation. More conservative approaches include rapid maxillary expansion, medications, and special dietary regimens.

TONSILLECTOMY AND ADENOIDECTOMY

Over 75% of tonsil/adenoid operations are performed on children less than 15 years of age, and 60% on children under 6 years of age. The usual age of children undergoing of this surgery is five years.

INDICATIONS FOR SURGERY

• Tonsillectomy and adenoidectomy, either in combination or separately, are most frequently performed to correct.

• Recurrent or chronic throat infection.

• Hypertrophy.

• Recurrent attacks of otitis media or chronic otitis media with effusion.

TONSILLECTOMY INDICATIONS

• Recurrent tonsillitis defined by a history of at least 7 episodes in the preceding year, or 5 episodes in each of the last 2 years, or 3 episodes in each of the last 3 years.

• Chronic tonsillitis persisting for at least 6 months despite intensive antibiotic therapy.

ADENOIDECTOMY

• Persistent obstruction – due to enlarged adenoids.

• Recurrent otitis medial with effusion.

• Contraindications: No absolute contraindications exist, except for conditions in which general anesthesia cannot be performed.

• Relative contraindications for total adenoidectomy. • A severe bleeding disorder, which could be overcome by preoperative,

intraoperative, and postoperative coagulation medicines and techniques, is a relative contraindication to adenoidectomy.

• ROLE OF ADENOIDECTOMY AND TONSILECTOMY

• Adenoidectomy with or without tonsillectomy is by far the most common treatment for nasal obstruction in children. Early intervention to correct nasal obstruction may lead to reversal of the associated craniofacial changes. Normalization of face form following adenoidectomy in a child can take five years. The deleterious effects of nasal obstruction are virtually complete by puberty so the window of opportunity is relatively brief. Delay in intervention may result in unsuccessful orthodontic treatment which may require orhthagnathic surgery at an older age

RHINITIS

There is no specific treatment for cold rhinitis, but it seldom lasts for longer than about a week.

Allergic rhinitis is treated with antihistamine drugs or local steroid sprays. Various drugs can be used to dry up excessive watery nasal secretions, and decongestants can sometimes be helpful.

Atrophic rhinitis is very difficult to treat. Sometimes a syringe, antibiotics or moistening sprays may be used to remove the crust blocking the airways.

Antihistamine drugs, taken by mouth, are convenient and relieve eye symptoms, running nose, sneezing and nasal irritation, but not nasal congestion. All are equally effective, but different people may find different methods more or less effective.

ORTHODONTIC TREATMENT

Orthodontic treatment is directed towards the prevention and correction of the malocclusion or to an adaptation of the dentition to the existing skeletal pattern or its predicted future growth which are obtained through the use of extractions,headgear therapy and classII elastics.

PREVENTION – MYOFUNCTIONAL APPLIANCES

Oral myofunctional therapy has been shown to be effective in correcting oral myofunctional disorders such as tongue thrust swallow, improper tongue and mouth resting posture, improper use of muscles of the mouth, tongue, and lips for chewing and swallowing, and late thumb/finger sucking habits.

Oral myofunctional therapy has two main goals:

Establishing an oral/facial resting posture with the tongue away from the teeth, against the palate, and lips together.

Establishing oral, lingual, and facial muscle patterns which

promote correct function of these structures during drinking, and chewing, collecting and swallowing of food.

These goals are accomplished by a series of exercises which focus first on retraining the oral, lingual and facial muscles so that the correct rest postures may be achieved; and then utilizing these new muscle patterns for habituating the correct labial/lingual rest postures and correct chewing and swallowing.

Children as young as four years of age may benefit.Habits such as mouth breathing, reverse swallowing and thumb sucking are corrected along with the alignment of the developing teeth. This will help future orthodontic treatment by making it less complex and decreasing the need for extractions.

• Murat Ozbek.( AO 1998) This study evaluated the use of functional –orthopedic devices in increasing oropharyngeal airway dimensions in children with class II skeletal pattern and clinically deficient mandibles . Comparisons were made between twenty six treated patients and fifteen controls. Of the twenty six treated cases, fourteen were treated using Harvold type activator and twelve were treated with Harvold type activator in conjunction with occipital high-pull head gear. Records were taken after class I relationship had been obtained. Compared with controls, oropharygeal airway dimensions increase significantly in treated patients especially those with sagittally smaller and more retrognathic maxillomandibular complexes and smaller oropharyngeal airway dimensions.

RAPID MAXILLARY EXPANSION

Rapid maxillary expansion (RME) has been recommended for the correction of transverse maxillary deficiencies with the additional benefits of increasing nasal airflow. The technique of RME was originated by Angel in 1860. In 1886 Eysell, an otorhinolaryngologist, proposed that the lateral expansion may relieve nasal obstruction. Since this time, there has been a long-standing controversy over the efficacy of RME in improving nasal respiration. During the course of RME, the maxillary and palatine bones are disarticulated along the mid-palatal suture and move laterally. These movements are rotatory the axis being beneath the cranial base with the most anterior and inferior partsmoving furthest. The expansion carries the lateral walls of the nasal air passages outwards increasing the trans-alar width.

The nasal valve in the normal nose presents the smallest nasal cross-sectional area and provides the most significant airflow resistance during breathing. The valve is in the region between the upper and lower lateral cartilages and the pyriform aperture, just beyond the anterior ends of the inferior turbinates. Aerodynamic studies and cadaver dissections have found the cross-sectional area of the nasal valve to be between 0.3 and 0.4 cm2 in each nostril.

.

Warren studied the effects of RME and surgical expansion on nasal

crosssectional area. Patients treated with RME resulted in an increase in nasal cross-sectional area of 45 per cent. Similarly, those patients treated with a total maxillary segmental osteotomy increased the cross-sectional area by approximately 55 per cent post-operatively. Despite a general increase in airway patency approximately one third of the subjects in both groups did not achieve enough improvement to eliminate the probability of obligate mouth breathing.

Nasal airway resistance (NAR) using posterior rhinomanometry in 26 patients receiving RME was studied by Timms. Reductions in nasal airway resistance were recorded in all cases with an average of 36.2 per cent.

Hartgerink, Vig and Abbot, have shown that despite a reduction in NAR following RME, this did not change the respiratory mode of the patient. The difficulty in treatment therefore lies with the inadequacy of determining which patients will respond to therapy

• Niall J McGuinness and James P. McDonald (EJO 2006) studied the relationship between RME and the change in natural head position resulting from the consequent change in airway resistance. A sample of 43 adolescent patients with uni or bilateral crossbite in the permanent dentition underwent RME as part of normal orthodontic treatment. Cephalograms in NHP were taken before, immediately after expansion and one year post expansion. No significant changes in the craniofacial angles were observed immediately after expansion. One year after expansion a statically significant reduction is seen with improved nasal respiration.

Anatomically, there is an increase in the width of the nasal cavity immediately following expansion, particularly at the floor of the nose adjacent to the midpalatal suture. As the maxillae separate, the outer walls of the nasal cavity move laterally. The total effect is an increase in the intranasal capacity. The nasal cavity width gain averages 1.9 mm, but can widen as much as 8 to 10 mm at the level of the inferior turbinates, while the more superior areas might move medially. AJO 1987 Bishara and Staley.

A number of rhinologists, including Gray, Braun, and Kressner, indicate that RME, in addition to its widening procedure, results in correction of septal deformity as a result of the lowering of the floor of the nasal cavity.

Hershey, Stewart, and Warren, and Turbyfill reported a reduction of nasal airway resistance by an average of 45% to 53% with RME. Wertz concluded that opening the midpalatal suture for the purpose of increasing nasal permeability cannot be justified unless the obstruction is shown to be in the lower anterior portion of the nasal cavity and accompanied by a relative maxillary arch width deficiency.

Therefore, it can be concluded that the effect of RME on the nasal airway will to a great extent depend on the cause, location, and the severity of the nasal obstruction.

Mean cross-sectional nasal cavity enlargements of between

1.4 mm and 4 mm for rapid expansion, 0.8 mm for a quad helix, and 0.5 mm for a removable appliance have been reported.

Rapid expansion exerts its effect by dilating the anterior nares, through the preferential expansion of the anteroinferior aspect of the nasal cavity. If, for example, the obstruction is posterior, rapid expansion will have little effect. Therefore expansion remains an unpredictable way of improving the nasal airway.

ORTHOGNATHIC SURGERY

Surgical superior impaction of the maxilla has become an accepted treatment for the correction of vertical maxillary excess and it does reduce nasal resistance, but it does not increase the percentage of nasal airflow. The nearer the patient is to completion of growth, the less likely it is that the long-term outcome will be affected by continuing growth.

A mean decrease in nasal resistance has been demonstrated after surgical maxillary impaction. It has been speculated that this change may be associated with the common postoperative increase in interalar width and widening of the external nares, which result in an opening of the liminal valve.

Even indirect evidence of forward movement of the base of the tongue, as a consequence of mandibular advancement with either protrusive appliances or orthognathic surgery,can still be inconclusive as the hyoid bone seems to move anteriorly with surgical advancement, but it subsequently moves back toward its preoperative position, yet remarkably its relationship with the cervical spine remains constant. The reason for this seems to involve an alteration of head posture, and cervical column angulation, which probably occurs as a physiologic adaptation to maintain the airway.Similarly, even though the tongue elongates anteriorly, and thickens posteriorly subsequent to surgical mandibular advancement, in the long term it also returns towards its preoperative shape.

• CONCLUSION

• Evaluation of children with nasal obstruction and dental abnormalities requires a multidisciplinary approach. The medical and dental literature concerning the issue is vast and many question remain unanswered so clear cooperation between the pediatricians, orthodontists and otolaryngologists is important

• The orthodontists must be familiar with the dental literature regarding dentofacial development and basic concepts of orthodontic intervention so as to provide optimal care for pediatric patients as they have an opportunity to examine and institute treatment to the patients at a very early age