Long Face Growth Patterns

Maxillary Vertical Excess with Mandibular Deformity

Jeffrey C. Posnick, DMD, MD

• Functional Aspects

• Clinical Characteristics

• Dental Findings

• Radiographic Findings

• Etiologic Considerations

• The Role of Growth Modification in the Preadolescent Patient

• The Orthodontic Camouflage Approach

• An Orthodontic Molar Intrusion Approach

• Definitive Reconstruction

• Surgical Planning Pitfalls

• Postsurgical Orthodontic Maintenance and Detailing

• Complications, Informed Consent, and Patient Education

• Malocclusion after Orthodontics and Orthognathic Surgery

• Temporomandibular Disorders: Effects of Orthodontics and Orthognathic Surgery

• Conclusions

The prevalence of a long face growth pattern at a prominent U.S. maxillofacial center was documented as representing 22% of jaw deformity evaluations as judged from the parameter of excessive anterior facial height.¹¹⁴ The lower anterior facial height was specifically long in 88% of the affected individuals.^54,74,75 The term long face is generally used to describe a maxillofacial growth pattern that typically also includes a gummy smile, an anterior open bite, and a lack of chin prominence. This combination of problems seems to be harder for the individual to live with; it results in a personal and family decision to seek treatment more frequently than most other patterns of dentofacial deformity (e.g., mandibular deficiency alone).¹¹² Halfway around the world, in South Africa, Reyneke estimated that, in his orthognathic practice, approximately 30% of those seeking treatment have a long face with complaints about a gummy smile and concerns caused by malocclusion.¹¹⁷

The basic diagnostic criteria for a long face growth pattern include an excessive anterior facial height (i.e., the elongation of the lower third) that leads to disproportion between facial height and width.26,28,69,70 Studies confirm that the excessive eruption of the posterior maxillary dentition causes the mandible to rotate downward and backward (clockwise rotation) and results in increased lower facial height.^24,34 This makes any baseline mandibular anteroposterior deficiency seem worse and any true mandibular prognathism seem better.^31,123 As the mandible rotates down and back during facial development, the lower incisors often adapt by becoming more upright, with crowding. The mandibular clockwise rotation tends to separate the upper and lower incisors vertically, thereby creating an open bite with an accentuated curve of Spee.⁷⁶ Not all long face growth patterns involve an anterior open bite. The maxillary incisors also supra-erupt.^111,139 The anterior bite may stay closed or even become deep, depending on the extent of maxillary and mandibular incisor supra-eruption.^{5,23,71,93–97,133} Whether the incisor relationship remains deep, normal, or open, lip incompetence (i.e., ≥4 mm of lip separation at rest) occurs, with mentalis strain that results from attempts to achieve lip closure.^27,99,100

Functional Aspects

• Wide lip separation occurs, with excessive effort required during attempts to achieve lip seal.

• Chronic obstructive nasal breathing as a result of increased intranasal airway resistance (e.g., septal deviation, enlarged inferior turbinates, tight nasal aperture, elevated nasal floor) is frequent (see Chapter 10).

• Classic articulation errors in speech as a result of the anterior open bite and lip incompetence are expected (see Chapter 8).

• Chewing and swallowing difficulties caused by the anterior open-bite malocclusion are expected (see Chapter 8).

• Detrimental effects on the dentition and the periodontium as a result of long-term traumatic malocclusion, the displacement of the teeth outside of the alveolar bone housing, or previous camouflage orthodontic and restorative treatments may be seen.

• The incidence of temporomandibular disorder may be higher than it is among individuals with normal jaw harmony and occlusion (see Chapter 9).

Clinical Characteristics

• Excessive anterior facial height, primarily in the lower third of the face

• Lip incompetence (i.e., resting lip separation of ≥4 mm)

• Increased exposure of the gingiva with a broad smile (i.e., a gummy smile)

• Increased frequency of anterior open bite (although one third of patients present with a normal or deep bite and only 15% have an open bit of >4 mm)

• Mandibular deficiency with Class II malocclusion is frequent (this can range from Class I to Class III)

• A mandible that is rotated downward and backward (i.e., clockwise rotation)

• An excessively full, curled lower lip when in a relaxed position

• Increased vermillion exposure of the lower lip

• A constricted or narrow alar base width, with depressed paranasal regions

• The appearance of a flat or sunken midface, without aesthetically pleasing facial curves or contours

• A negative vector relationship of the ocular globe to the lower eyelid

Dental Findings

• Anterior open bite (may be normal or deep)

• Excessive alveolar height in the anterior maxillary region (this will raise the floor of the nose and partially obstruct nasal airflow)

• Mandibular incisors that are upright, with crowding

• Accentuated curve of Spee as a result of the overeruption of the mandibular incisors

• Tendency toward a narrow, V-shaped maxillary arch with posterior crossbites (this is seen in approximately 50% of patients)

• Occlusal surface enamel wear on the posterior teeth as a result of grinding (secondary occlusal trauma) or previous occlusal equilibration performed in an attempt to close the anterior open bite

Radiographic Findings

• Excessive eruption of the maxillary posterior teeth (i.e., the distance from the palatal plane to the cusps of the molars)

• Maxillary horizontal deficiency

• Clockwise rotation of the maxilla (i.e., an increased palatal plane angle)

• Increased lower anterior facial height

• Clockwise rotation of the mandible (i.e., an increased mandibular plane angle)

• Normal or short mandibular ramus height

• Mandibular posterior teeth not excessively erupted

• Excessive eruption of the maxillary and mandibular incisors: with enough anterior hypereruption, a normal or deep overbite is more likely

• Measurable excessive eruption of the maxillary incisors (i.e., the distance from the floor of the nose to the incisal edge)

• Measurable excessive eruption of the mandibular incisors (i.e., the distance from the menton to the incisal edge)

Fields and colleagues presented simplified cephalometric diagnostic criteria.⁴⁴ If a patient has all three of the following criteria, he or she can be considered to have a long face growth pattern:

1. An increased mandibular plane angle

2. An increased total anterior facial height

3. A decreased percentage of upper to lower facial height

Etiologic Considerations

Current thinking is that both environmental influences and inherited tendencies play a role in the development of a long face.53,66,67,85–87 A significant percentage of patients with long faces have been found to have an increased oral and decreased nasal breathing pattern.^{25,33,37,52,59,82,134,146,150} Interestingly, nasal obstruction is not always present with long face growth patterns, but an open-mouth posture during development is typical. Other causes of an open-mouth posture in the preadolescent patient have been shown to result in similar long face dysmorphology.^{1,2,4,51,61,78,80,140} This includes muscle weakness syndromes (e.g., Moebius syndrome, facial nerve palsy, cerebral palsy, muscular dystrophy) and the presence of a large tongue (e.g., Beckwith-Wiedemann syndrome, hemangioma, vascular malformations, neurofibromatosis, Proteus syndrome; see Chapter 4).

There is experimental animal model research to support the theory that a long face anterior open-bite malocclusion is a physiologic adaptation to an open-mouth protrusive tongue posture that is present during facial development (see Chapters 4 and 10).^62–65 It has also been clarified that, in humans, a resting open-mouth protrusive tongue posture is an etiologic factor in the development of a long face with an anterior open bite. Interestingly, the intermittent occurrence of tongue thrust during speech and swallowing is not thought to be the cause of an open bite. In fact, periodic tongue thrusting is an adaptive response to an open bite rather than the cause.⁴⁷ When the incisors overlap in an average way (i.e., with a normal overbite), the normal-sized tongue is naturally placed behind the teeth to create the necessary anterior seal for successful swallowing and the articulation of specific consonant sounds (see Chapter 8). In the presence of anterior open bite, the normal tongue must protrude past the teeth to seal against the lips. This is an expected adaptive mechanism to assist with swallowing and speech. Confirmation that the protrusive tongue position during swallowing and speech is a reversible adaptation has been routinely documented after the individual with a long face and an anterior open bite undergoes successful orthognathic surgery and orthodontic treatment.^89,142,155 When the open bite is closed with the use of sound biologic mechanics (i.e., without orthodontic dental compensation) and when lip competence is achieved through surgery (i.e., there is no longer excess lower facial height), there is a fairly reliable elimination of the tongue thrust without the need for active myofunctional physical therapy retraining. However, if a skeletal anterior open bite has been closed with the use of unsound orthodontic maneuvers (i.e., excessive eruption of the anterior teeth or buccal tipping of the molars outside of the alveolar bone housing) and if lip competence is not achieved (i.e., inadequate facial height shortening), dental relapse is to be expected. In this case, tongue thrusting should not be blamed for the recurrent malocclusion.

The Role of Growth Modification in the Preadolescent Patient

When standard growth modification maneuvers for a long face growth pattern are attempted in the preadolescent patient, the primary objective is to restrain the hypereruption of the posterior maxillary teeth. In theory, this would limit the abnormal downward and backward rotation of the mandible. Unfortunately, effective and practical methods for accomplishing this seemingly limited objective have been difficult to orchestrate. It has also been shown that the natural progression of the deformity may persist through adolescence. This means that the effective containment of the maxillary posterior dental hypereruption would need to continue throughout the teenage years. The two traditional methods that are used to impede excessive vertical growth of the posterior maxilla are 1) the use of high-pull headgear connected to a complete or partial maxillary fixed appliance and 2) the use of a functional intra-oral appliance that incorporates a bite-block device (i.e., an activator) between the teeth.

The intraoral functional appliance is usually designed to exert force on the posterior teeth when the masticatory muscles contract. The occlusal force is then transferred through the biting surfaces of the upper and lower posterior teeth to the periodontal ligaments to limit molar eruption. To be effective, most clinicians recommend that the functional appliance be worn for 14 to 16 hours per day. When headgear is used, it is designed to apply direct external force to the teeth through a fixed maxillary appliance. Unfortunately, true vertical pull is almost impossible to achieve, and this results in a degree of added backward pressure. Because the majority of patients with long faces do not have protrusion of the maxilla, this unavoidable posterior force is counterproductive and results in further horizontal maxillary deficiency. The combination of vertical intrusion vectored headgear and an intra-oral functional appliance to affect the posterior dentition—when initiated during childhood and sustained through the teenage years in a compliant child—is thought to have the potential to produce improvement in the patient with a long face growth pattern. In all but borderline long faces, which are recognized during childhood, growth modification is not likely the preferred approach.

The Orthodontic Camouflage Approach

The patient with a long face often perceives a visual prominence of his or her upper incisors. For this reason, it is apparently tempting for the orthodontist to proceed with a camouflage treatment plan to neutralize the occlusion via the retraction of the upper incisors. This approach seems to be especially difficult for the orthodontist to avoid when viewing the problem primarily as a Class II malocclusion without fully considering the vertical and horizontal skeletal disharmony, the lip incompetence, the upper airway dysfunction, and the overall facial aesthetics. The extraction of the maxillary first premolars followed by the retraction of the anterior teeth will improve and may even neutralize the occlusion, but it does nothing to relieve the vertical facial problem, and it will further accentuate the horizontal facial deficiency. As the incisors are orthodontically retracted, they are also elongated (i.e., extruded), and the nasolabial angle opens, which results in unattractive effects on the lips and the nose.

Before embarking on an orthodontic camouflage approach, the clinician should confirm that the patient and his or her family understand the aesthetic limitations of closing the anterior open bite by extruding the incisors (i.e., residual or worsening gummy smile, residual lip incompetence with mentalis strain, lack of facial aesthetic improvement). The patient’s long-term dental stability and periodontal health must also be considered. In addition, the maxilla, the mandible, and the chin will remain horizontally deficient and vertically long, thereby further accentuating lip incompetence and the long, flat, retrusive appearance of the profile.

An Orthodontic Molar Intrusion Approach

Sato and colleagues believe high-angle Class II malocclusions can be corrected with the use of “multiloop edgewise arch wires.”¹²⁴ With the use of tip-back mechanics and vertical elastics, the researchers believe that the occlusal plane inclination can be altered by intruding the molars via the autorotation of the mandible and the closure of the open bite. Unfortunately, scientific evidence in support of this method of treatment for a patient with a long face and an anterior open bite has not been forthcoming.

With the use of skeletal temporary anchorage devices, the intrusion of the molars has been recommended by some to close an open bite.105,157,158 Man-Suk and colleagues completed a study to examine the long-term stability of anterior open-bite correction via the intrusion of the maxillary posterior teeth in adults.⁸⁸ In the first group (n = 5 adults), mini-screw implants were placed on the buccal and palatal sides, between the roots of the maxillary second premolars and first molars and between the roots of the maxillary first and second molars. Intrusion forces were directly applied to the molars with elastomeric chains. In the second group (n = 4 adults), mini-screw implants were placed on the buccal side only between the roots of the maxillary second premolars and first molars and between the roots of the maxillary first and second molars. A rigid transpalatal arch was placed before applying the intrusive forces to prevent the buccal tipping of the teeth. Lateral cephalograms were taken at the initial evaluation and again at 1 and 3 years after treatment. The cephalograms were traced and analyzed. The study documented that the maxillary first molars were intruded on an average of 2.39 mm during treatment, with relapse of 0.45 mm at the 3-year follow up (i.e., 22.9% relapse). A majority of the relapse occurred during the initial posttreatment year. The molar relapse had a significant effect on the eventual incisal overbite. There was no significant difference in molar relapse or the maintenance of overbite between the two different methods of skeletal anchorage used. It would appear as though there is currently no known way to fully retain an orthodontically intruded molar.

For patients with borderline long face growth patterns in whom the open bite has been successfully closed with the use of orthodontic mechanics and in whom the remaining gummy smile and lip incompetence is only mild, a vertical reduction with horizontal advancement genioplasty may improve the profile aesthetics and lip competence enough to be a satisfactory compromise for the patient (see Chapter 37 and 40).