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Diagnosis of the vertical dimension
Diagnosis of the Vertical Dimension James L. Vaden and Lloyd E. Pearson The vertical dimension problem is complex and multifactorial, Not only must the clinician recognize a vertical discrepancy abnormality, he/she must be able to recognize its numerous components and understand their interrelationships, Many scientific investigators and orthodontic clinicians have contributed to the body of knowledge to which we have access. This article reviews some of the pertinent literature and offers some diagnostic and treatment planning suggestions to the clinical specialist who struggles with the vertical dimension enigma on a daily basis, (Semin Orthod 2002;8: 120-129,) Copyright 2002, Elsevier Science (USA). All rights reserved.
he h u m a n face has been the subject of study since man could first express himself. As civilizations have risen and subsequently faded away, one thing that has remained is art, in most cases, drawings, paintings, and so on of faces. During the Renaissance, da Vinci, Michaelangelo, and D u h r e r led o t h e r artists to study faces. Facial p r o p o r t i o n was discovered; there were standards set for balance and h a r m o n y of the lower face. In our specialty of orthodontics, Angle was vitally c o n c e r n e d about the face. In his sixth edition, 1 he states, "One of the evil effects of malocclusion is the marring or distorting of the normal facial lines. It follows that, in the application of the principles of orthodontia, our efforts should be so directed as to mold and modify these lines of i n h a r m o n y to those of h a r m o n y and facial beauty so far as lies within the range of the possibilities of art, and of the type and t e m p e r a m e n t of the individual. O u r opportunities for benefiting humanity are very great in this field, far exceeding those offered by any other branch of dental science, for patients with facial lines so distorted as sometimes to be a marked deformity and a source of constant humiliation to themselves and their friends may
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Prom the Department of Orthodontics, University of Tennessee, Memphis, TN; and a Private Practice, Edina, MN. Address cor~rspondence to James L. Vaden, DDS, M8, Department of Orthodonti~, University of Tennessee, Health Seienee Center, 875 Union Avenue, Memphis, TN 38163. Copyright 2002, Els~ier Science (USA). All rights trserved. 1073-8746/02/0803-0003535.00/0 doi:l O.1053/sodo. 2002.125431
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now be so treated as to bring about a complete transformation of the facial expression, even to the establishment of lines of beauty." Tweed revolutionized orthodontic diagnosis because of his c o n c e r n for the balance and harm o n y of the lower face. Many in our specialty have studied the face, z-6 developed diagnostic guidelines for quantifying facial balance, 7-u and proposed treatment regimens that give the orthodontic clinician a greater certainty that facial balance and h a r m o n y is an attainable goal for their patients. The underlying theme that surfaces from all artists and orthodontic investigators is the concept that there c a n n o t be good balance and h a r m o n y in the lower face unless the vertical dimension is within normal limits. The most important prerequisite for facial balance is a normal vertical dimension of the lower face. Poulton 12 c o n d u c t e d a study on cervical traction and f o u n d that large lower anterior facial heights were most often associated with a displeasing face. In their article on soft-tissue profile preference, DeSmit and DermauO 3 created three different series of nine profile photographs so that a total of more than 200 profiles could be ranked by graduate dental students. They f o u n d that differences in gender and orthodontic knowledge of the students seemed to have no significant influence on their esthetic preference. The results of their study confirmed the importance of anteroposterior deviations but suggested that unaesthetic facial profiles that were a result of anteroposterior deviations were completely overshadowed by long-face fea-
Seminars in Orthodontics, Vol 8, No 3 (September), 2002: pp 120-129
Diagnosis of the Vertical Dimension
t u r e s - - t h e long-face feature being m o r e unaesthetic. Because of the challenge of the vertical dimension, the subject of this article is of extreme i m p o r t a n c e to the orthodontic specialist. Not only must the specialist recognize the problem, the specialist must u n d e r s t a n d the diagnosis of the p r o b l e m so that all facets and components of the vertical dimension e n i g m a are understood. T h e clinician must be able to recognize the various c o m p o n e n t s of a vertical dimension abnormality and u n d e r s t a n d the interrelationship of all the elements of the problem. Before discussing the abnormal, it is p r u d e n t to understand the normal. Two of the most accepted descriptions or publications of vertical facial proportions have b e e n published by Frakas 14 and Frakas and Munro. 15 In these, they describe the ideal face as vertically divided into equal thirds by horizontal lines that approximate the hairline, the bridge of the nose, the ala of the nose, and m e n t o n (Fig 1)J 6 Figure 1 also shows that in the ideal vertically p r o p o r t i o n e d face there is a further division of the lower one
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Figure 1. The ideal facial proportions as described by Frakas 14 and Frakas and Munro. 15 The frontal view of the face is divided into equal thirds by horizontal lines that approximate the hairline, the bridge of the nose, and the ala of the nose and menton. The lower third is further divided into an upper third and a lower two third.
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third of the face into an u p p e r one third and a lower two third. These divisions of the face can be used by the clinician to help diagnose vertical dimension problems. For example, does a patient have a disproportionately long lower facial height because of vertical maxillary excess or to excessive chin height? Conversely, is a short facial height caused by vertical maxillary deficiency or a short chin height? 17 By using these accepted proportions as a guide, the patient shown in Figure 2 has an excessive lower anterior facial height, whereas the patient shown in Figure 3 has diminished lower anterior facial height. Although it is evident that both have vertical dimension abnormalities by looking at the face, measuring the facial proportions confirms this intuitive conclusion. A careful determination of the vertical proportions of the face is therefore the first step in the diagnosis of a vertical dimension problem. Role of Skeletal and Dental Relationships After examining the face and quantifying its proportions, the skeletal pattern and the teeth and their relationships to each other must be scrutinized. However, a diagnosis of the vertical dim e n s i o n is m o r e complicated because vertical discrepancy malocclusions are nmltidimensional. For example, dentoalveolar abnormalities can impact the skeletal pattern, and p o o r skeletal patterns can cause dentoalveolar compensations that are difficult for the clinician to correct. T h e following variations can be present, either alone or in combination: (1) maxilla: maxillary posterior alveolar excess and inferiorly positioned maxilla and (2) mandible: mandibular posterior alveolar excess and short mandibular rami. O t h e r abnormalities may include superiorly positioned condylar fossa, obtuse cranial base angle, and condylar resorption. Any of these conditions, with or without aberrant m a n d i b u l a r growth rotation, can be a causative factor in the vertical discrepancy malocclusion. Condylar
Growth
A c o m m o n scenario affecting the skeletal problem is m a n d i b u l a r growth a n d growth rotation, which unfavorably impacts dentoalveolar devel-
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Figure 2. An example of a patient with an excessive lower facial height. o p m e n t in both the maxilla and mandible. Bjork is-21 and Bjork and Skieller 2:~,24 have perf o r m e d n m n e r o u s studies that have shown that the most c o m m o n direction of condylar growth is vertical, with some anterior c o m p o n e n t . Patients with a p r o n o u n c e d short lower anterior facial height (Fig 4A and B) generally exhibit upward and forward condylar growth (Fig 5). These individuals generally have a d e e p vertical overbite with a d e e p mentolabial sulcus and a strong overclosed appearance. 25 In contrast, pa-
Figure 3. An example of a patient with a diminished lower facial height.
tients with long-face syndrome (Fig 6A and B) have a m o r e posteriorly directed growth pattern of the m a n d i b u l a r condyle (Fig 7). 26,27 These backward growth rotators have increased anterior facial height, a m o r e posterior position of the chin, and in e x t r e m e cases, an anterior o p e n bite may develop. Serial images of the patient taken to m o n i t o r the direction of condylar growth would be very useful for the diagnosis of vertical growth. At the present time, serial imaging poses certain concerns, most significantly
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Figure 4. A patient with a pronounced short lower anterior facial height. (A) The cephalometric radiograph is also shown. (B)
radiation exposure. Advances in imaging technology may, in the future, p e r m i t the clinician to use these m e t h o d s for diagnostic purposes with greater safety. An understanding of the maxillomandibular growth rotation of the patient would be most helpful in the diagnosis of vertical variations. Bjork u8 has contributed information that offers some guidelines for the clinician to assist in the determination of the growth rotation of the mandible so that the c o n c o m i t a n t vertical changes are m o r e easily understood. Bjork's
m e t h o d of prediction of condylar growth rotation from a c e p h a l o g r a m offers the clinician some guidelines. Bjork identified seven specific structural features that m i g h t develop as a result of r e m o d e l i n g during a particular type of growth rotation. Bjork's suggestions for predicting condylar rotation have, however, not b e e n widely used by the specialty because (1) some of the indicators cannot be easily seen on the average cephalogram, (2) the use of the indicators is vmT time-consuming for the clinician, and (3) there has b e e n no scientific validation of the suggested
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the backward rotator exhibits (1) a straight inclination of the condyle, (2) a relatively straight mandibular canal, (3) the symphysis slopes forward and, (4) lower anterior facial height is long. Isaacson, 29 Isaacson et al, 3° and Schudy, ~ following on Bjork's reports, studied jaw rotation caused by vertical condylar growth. A succinct summary of the findings of these investigators is that a forward mandibular rotation occurs when vertical condylar growth exceeds the sum of the vertical growth of the maxillary sutures and the maxillary and mandibular alveolar processes. If growth of the maxillary sutures and the maxillary/mandibular alveolar processes exceeds vertical condylar growth, a backward rotation occurs, and the face becomes longer. An understanding of the effect of condylar growth on mandibular position is fundamental if the clinician is to adequately and appropriately diagnose a vertical dimension abnormality.
Figure 5. An example showing upward and forward condylar growth. indicators because of difficulties e n c o u n t e r e d in study design. Some in the specialty also question whether several of the suggestions are valid indicators of a particular type of growth rotation. However, when used for their intended purpose, as guidelines only, the indicators have some useful clinical applications in the diagnosis of the patient with vertical dysplasia (Table 1). Using Bjork's guidelines, it is interesting to study Figures 4B and 6B. Figure 4B, the forward rotator, exhibits several of Bjork's indicators including observations that (1) the condylar head curves forward, (2) the mandular canal is curved, (3) the symphysis has a backward cant, (4) the interincisal angle is obtuse and, (5) lower anterior facial height is short. Figure 6B,
Anterior and Posterior Facial Height Vertical dimension skeletal abnormalities are not solely caused by condylar growth direction. They are also caused by differences in anterior facial height and posterior facial height development. These differences in height development can lead to rotational growth or to changes in mandibular position that greatly influence the position of the chin. ~° Etiologies influencing unfavorable differences in development of anterior and posterior facial height are nmltifactorial. These factors can, for simplicity, be subdivided into those caused by (1) dentoalveolar developm e n t and (2) environmental factors.
Dentoalveolar Development Issacson et al 3~ studied dentoalveolar developm e n t in three groups of subjects--those with
Table 1. Bjork's Seven Structural Guidelines 2s
Inclination of the condylar head Curvature of the m a n d i b u l a r canal Shape of the m a n d i b u l a r lower border Inclination o f the symphysis (Anterior aspect j u s t below "B" point) Interincisal angle l n t e r p r e m o l a r or intermolar angles Anterior lower face h e i g h t
Fo~t~ard Pvotator
Backward Rotator
Cupees forward a n d back Curved Curved downward Slopes backward Vertical or obtuse Vertical or obtuse Short
Straigbt or slopes u p Straight Notchcd Slopes fi)iveard Acute Acute Tall
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Figure 6. An example of a patient with long-face syndrome. short anterior facial height, those with average anterior facial height, and those with excessive anterior facial height. T h e a m o u n t of maxillary posterior alveolar d e v e l o p m e n t was t o u n d to decrease as the MP-SN angle decreased. In patients with long anterior facial height (high MP-SN angles), the m e a n distance f r o m the occlusal plane to the inferior edge of the palate was 22.50 m m . This distance decreased to 19.6 m m for the average g r o u p and 17.1 m m for the g r o u p with
short anterior facial height (low MP-SN angles). This difference of 5.1 m m of dentoalveolar dev e l o p m e n t between the high angle and low angle groups is of significance. M a n d i b u l a r p o s t e r i o r alveolar d e v e l o p m e n t similarly d e c r e a s e d with decreases in the MP-SN angle b u t m u c h less dramatically t h a n those f o u n d in the maxilla. M a n d i b u l a r h e i g h t showed a m e a n of 31.2 m m for the l o n g anterior face h e i g h t g r o u p , 28.2 for the average
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Figure 7. An example showing a posterior-directed growth pattern of the mandibular condyle.
group, a n d 28.3 for the s h o r t a n t e r i o r face h e i g h t group. The findings of the Issacson et a133 study were confirmed in a study p e r f o r m e d by J a n s o n et al. 34 These investigators f o u n d that all dentoalveolar heights were significantly greater in long anterior facial height patients than in patients with n o r m a l facial height. Also, in the short lower anterior facial height, all dentoalveolar heights were significantly shorter than in the n o r m a l lower anterior facial height group. T h e differences in dentoalveolar development, most particularly in the maxilla, have a significant impact on the anterior facial height of the orthodontic patient. Moller and Ingerval135 and T h i l a n d e r :~6 have postulated that excessive maxillary posterior dentoalveolar develo p m e n t is associated with weaker masticatory musculature in high-angle patients c o m p a r e d with the strong musculature c o m m o n l y associated with short anterior facial height patients.
Enviornmental Role--Swallowing and Tongue Posture T h e role of tongue posture, swallowing, and breathing are still subjects of debate, argument, and study in orthodontics. Their respective impact on the vertical dimension are in n e e d of continued study and research.
Mouth breathing. T h e relationship between m o u t h breathing, altered posture, and the dev e l o p m e n t of malocclusion is not as clear cut as the theoretical o u t c o m e of shifting to oral respiration m i g h t a p p e a r at first g l a n c e Y Recent experimental studies have only partially clarified the situation. C u r r e n t e x p e r i m e n t a l data for the relationship between malocclusion and m o u t h breathing are derived f r o m studies of the nasal/ oral ratio in normal versus long-face c h i l d r e n Y T h e data from the study show that both normal and long-face children are likely to be predominantly nasal breathers u n d e r laboratory conditions. A minority of the long-face children had less than 40% nasal breathing, whereas n o n e of the normal children had such low nasal percentages. W h e n adult long-face patients are examined, the findings are similar: the n u m b e r with evidence of nasal obstruction is increased in comparison to a n o r m a l population, but the majority are not m o u t h breathers in the sense of p r e d o m i n a n t l y oral respiration. Airway problems, such as large adenoids, tonsils, or blocked ail~vays caused by septum deviations, large conchae, or allergies are frequently observed in high-angle patients and may affect m a n d i b u l a r posture, allowing m o r e f r e e d o m for posterior eruption. This hypothesis is s u p p o r t e d by Linder-Aronson 39,4° who showed closing of the m a n d i b u l a r plane angle and reduction in the anterior face height after removal of adenoids and tonsillectomy. It appears that research on respiration, up to the present time, has resulted in two opposing views: (1) total nasal obstruction is highly likely to alter the pattern of growth and lead to malocclusion in e x p e r i m e n t a l animals and humans, and individuals with a high p e r c e n t a g e of oral respiration are overrepresented in the long-face population, but (2) the majority of individuals with the long-lace pattern of deformity have no evidence of nasal obstruction and must therefore have some o t h e r etiologic factor as the principal cause. In conclusion, it appears that m o u t h breathing may contribute to the d e v e l o p m e n t of orthodontic p r o b l e m s but is difficult to indict as a frequent etiologic agent. Clinically, most orthodontists refer m o u t h breathers to an otolaryngologist tbr an evaluation. This p r o b l e m should be carefully evaluated during the diagnosis of a patient with excess vertical dimension.
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Swallowing and tongueposture. O n e viewpoint holds that t o n g u e thrust swallowing is seen in (1) y o u n g e r children with r e a s o n a b l y n o r m a l occlusion in w h o m it r e p r e s e n t s only a transitional stage in n o r m a l physiologic m a t u r a t i o n a n d (2) in individuals who have displaced incisors. In the latter, it is an a d a p t a t i o n to the space b e t w e e n the teeth. O t h e r s a r g u e that t o n g u e thrust swallowing simply has too s h o r t a d u r a t i o n to have an i m p a c t o n t o o t h position. Pressure by the t o n g u e against the teeth d u r i n g a typical swallow lasts for a p p r o x imately 1 second. A typical individual swallows a b o u t 800 times p e r day while awake b u t has only a few swallows p e r h o u r while asleep. T h e total p e r day, t h e r e f o r e , is usually u n d e r 1,000. O n e t h o u s a n d seconds of pressure, of course, totals only a few minutes, n o t nearly e n o u g h time, it is argued, to affect the equilibrium. 41 Most clinicians believe that if a patient has a forward resting posture of the tongue, the duration of this pressure, even if very light, could affect tooth position, vertically or horizontally. Tongue-tip protrusion during swallowing is sometimes associated with a forward tongue posture. During the diagnosis of the patient with a vertical dimension problem, the clinician must u n d e r s t a n d that condylar growth, sutural lowering of the maxillary complex, dentoalveolar development, dental eruption, and the patient's oral e n v i r o n m e n t / h a b i t s are interrelated. T h e r e is not generally a single causative factor that predisposes the patient to too m u c h or too little vertical d e v e l o p m e n t of lower facial height. To simplify, one might conclude as a general rule, that when vertical condylar growth exceeds tooth eruption (alveolar development), forward m a n d i b u l a r rotation occurs. T h e result is increased posterior facial height a n d an increase in the ratio of posterior facial height to anterior facial height. Conversely, if dentoalveolar growth and tooth eruption are greater than vertical condylar growth, the resultant m a n d i b u l a r change is backward rotation. T h e anterior facial h e i g h t / p o s t e r i o r facial height ratio decreases. 42 Environmental factors can play a role, but the role is, at times, difficult to assess and varies f r o m patient to patient.
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Diagnostic Considerations Steep Excess Vertical Pattern: The Backward Rotator During differential diagnosis of the high-angle patient, two questions must be asked. First, where should the teeth be positioned? For the patient with long anterior facial height, the mandibular anterior teeth are most often positioned in a m o r e retracted posture over basal bone. Lip p r o c m n b a n c y can be best resolved if the mandibular anterior teeth are upright. T h e a m o u n t of uprighting that must be achieved is a matter of (1) clinical preference and must be determ i n e d during the t r e a t m e n t p l a n n i n g phase of the t r e a t m e n t protocol or (2) the dictates of the malocclusion. If indeed the facial profile of the patient with excess vertical dimension is long, a vertical reduction genioplasty can be effective for facial esthetics. It is f u n d a m e n t a l for the clinician to be able to visualize the posttreatm e n t positions of the m a n d i b u l a r anterior teeth during t r e a t m e n t plan preparation. Secondly, will extractions be necessary? For m a n y patients with excessive lower anterior facial height, extractions may be necessary. T h e question of which teeth should be extracted can be answered only after a t h o r o u g h and accurate differential diagnosis.
The Overdosed Forward Rotator Patients with short anterior vertical facial height have a unique set of problems that require different diagnostic considerations. The following diagnostic guidelines should be considered when a patient with this skeletal pattern is treated without surgical intervention. Mandibular incisors, if well aligned before treatment, can be allowed to remain in their p r e t r e a t m e n t position. Uprighting of mandibular incisors has an adverse impact on facial esthetics of the low-angle patient. However, the m a n d i b u l a r incisors, if malaligned, should not be proclined beyond their bony support for the p u r p o s e of alignment. Some overclosed forward rotator malocclusions are characterized by a d e e p vertical overbite, maxillary incisor protrusion, a n d / o r crowding. Correction of the overbite for these patients is best accomplished by intrusion and retraction of the maxillary incisors.
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Treatment Concerns During the diagnosis of the vertical dimension problem, the clinician must be attentive to the force systems that are p l a n n e d for treatment and understand that undesirable reactions to incorrectly applied fbrce systems are disastrous. Posterior facial height must be carefully controlled for the high-angle patient because an increase in posterior facial height will result in an increase in anterior facial height. 434~ An increase in anterior facial height of high-angle patients is calamitous. An important mechanical tooth manipulation that must be accomplished during the treatment of the patient with excess vertical dimension is prevention of extrusion of the mandibular posterior teeth, assuming that the maxillary posterior vertical dimension is controlled by intrusive forces (ie, headgear or other methods). Extrusion in the molar areas will prevent successful correction of the malocclusion with excess vertical dimension and long lower anterior t:ace height. It is important for the clinician to understand these concepts during diagnosis and treatm e n t planning so that extraoral traction can be planned to help control the vertical dimension during treatment. There should be intrusive forces to the posterior segments of both arches. Additionally, Class II elastic wear can be one of the most detrimental force applications that is applied to a patient with long lower anterior facial height. If Class II elastics are used indiscriminately on the high-angle patient, the mandible drops down and back and increases the sagittal discrepancy. Therefore, Class II elastic use, or the absence of it, must be planned for during diagnosis and treatment planning. Pearson 4~ has published his results using vertical pull chin cups and has provided evidence that their use can create some effective skeletal changes for the long-face patient. A thoughtful diagnostician nmst consider the use of whatever means is necessary to impact treatment and prevent the lengthening of lower anterior facial height during the course of treatment.
Summary The orthodontic clinician must make a careful differential diagnosis for each patient who seeks his or her care. The diagnosis must analyze all
three c o m p o n e n t s of a malocclusion facial, dental, and skeletal. Each c o m p o n e n t must be carefully studied and u n d e r s t o o d so that (1) the p r o p e r questions are asked and (2) the correct diagnostic decisions are made to lead to an effective treatment plan. Diagnosis of the vertical dimension is a con> plex problem. Yet, it can be as simple as studying a face and applying c o m m o n sense diagnostic tools to ascertain the reason that the lower face is too long or too short. The vertical dimension has been a subject of study and debate since orthodontics became a specialty. Researchers in the field of vertical dimension diagnosis, including Bjork, is Schudy, 27 Nielsen, 25 Isaacson, 29 Pearson, ~6 and others, have provided the specialty many useful guidelines and concepts that can be used by every orthodontic clinician as they diagnose a malocclusion that is complicated by a vertical dimension discrepancy. Orthodontists should continue to use the work of these researchers and clinicians for a foundation as more studies are u n d e r t a k e n that will yield more knowledge so that diagnosis of the vertical dimension becomes less art and more science.
References 1. Angle EH: Malocclusion of the T e e t h a n d Fractures of the Maxillae (ed 6). Philadelphia, PA, SS "v~qlite Co, 1900, p 15 2. Tweed el: Indications for the extraction of teeth in orthodontic procedure. Am J O r t h o d 30:405-428, 1934 3. Peck H, Peck S: A concept of facial esthetics. Angle O r t h o d 40:284-317, 1970 4. Burstone CJ: Lip posture a n d its significance in treatm e n t planning. A m J O r t h o d 53:262-284, 1967 5. Hulsey CM: An esthetic evaluation of lip-teeth relationships present in the smile. A m J O r t h o d 57:132-144, 1970 6. Peck S, Peck L: Selected aspects o f the art a n d science of facial esthetics. Semin O r t h o d 1:105-126, 1995 7. Merrifield LL: T h e profile line as an aid in critically evaluating facial esthetics. A m J O r t h o d 52:804-821, 1966 8. Czarnecki ST, N a n d a R, Currier F: Perceptions o f a balanced Facial profile. A m J Orthod, Dentnt~tcial Orthop 104:180-187, 1993 9. Ricketts RM: Divine proportions in facial esthetics. Clin Plastic Surg 9:401-422, 1982 10. Steiner CC: Cephalometrics tor you a n d me. A m J Ortfiod 39:729-755, 1953 11. Holdaway RA: A soft tissue analysis a n d its use in orthodontic t r e a t m e n t planning: Part I. Aau J O r t h o d 84:128, 1983 12. Poulton DR: T h e influence of extraoral traction. A m J O r t h o d 53:8-18, 1967 13. DeSmit A, D e r m a u t L: Soft-tissue profile preference. A m J O r t h o d 86:67-73, 1984
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14. Frakas LG: AnthropomeUT of the Head and Face in Medicine. New York, NY, Elsevier Science, 1981 15. Frakas LG, Munro JR: Anthropometric Facial Proportions in Medicine. Springfield, IL, Charles C. Thomas, 1987 16. Proffit WR: Diagnosis and Treatment Planning in ContempormT Orthodontics. St. Louis, MO: Mosby, 2000 17. SaJv'er D, Proffit W, Ackerman J: Diagnosis and treatlnent planning in orthodontics fl'om orthodontics, in Graber TM, Vanarsdall RL (eds): Current Principles and Techniques (ed 3). St. Louis, MO, Mosby, 2000 18. Bjork A: Facial growth in man, studied with the aid of metallic implants. Acta Odontol Scand 13:9-34, 1955 19. Bjork A: Variations in the growth pattern of the human mandible: longitudinal cephalometric study by the implant method..] Dent Res 400-411, 1963 20. Bjork A: Sntural growth of the upper face studied by the implant method. Acta Odoutol Scand 24:109-129, 1966 21. Bjork A: The use of metallic implants in the study of" facial growth in children, method and application. AlnJ Phys Mlthropol 29:243-254, 1968 22. Skieller V: Cephalometric analysis in the treatment of overbite. Rep Congr Eur Orthod Soc 147-I57, 1967 23. Bjork A, Skieller V: Facial development and tooth eruption, an implant study at the age of puberty. Am .] Orthod 621:339-383, 1972 24. Bjork A, Skieller V: Normal and abnormal growth of the mandible: A synthesis of longitudinal cephalometric implant studies over a period of twenty five years Eur J Orthod 5:1-46, 1983 25. Neilsen i L: Vertical malocclusions: Etiology', development, diagnosis and some aspects of treatment. Angle Orthod 61:247-260, 1991 26. Pearson LE: Vertical control iu treaUnent of patients having backward rotational growth tendencies. Angle Orthod 48:130-140, 1978 27. Schudy FF: Vertical growth vs anteroposterior growth as related to fimction and treatment. Angle Orthod 34:7593, 1964 28. B]ork A: Prediction of mandibular growth rotation. AmJ Orthod 55:585-599, 1969 29. Isaacson RJ: The geometry of~acial growth and its effects on the dental occlusion and facial form. J Charles H. Tweed Int Found 9:21-38, 1981 30. Isaacson RJ, et al: Effects of rotational jaw growth on the occlusion and profile Am J Orthod 3:276-286, 1977 31. Schudy FF: The rotation of the mandible resuhing fi'om growth: Its implication in orthodontic treatment. Angle Orthod 35:36-50, 1965 32. Proffit WM: The development of orthodontic problems, in Proffitt WM, Fields HW (eds): Contemporaly Orthodontics. St. Louis, MO, Mosby, 2000, pp 102-106
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33. IsaacsonJR, lsaacson RJ, Speidel TM, et al: Extreme variation in vertical facial growth and associated variation in skeletal and dental relationships. Angle Orthod 41:219228, 1971 34. Janson G, Metaxas A, Woodside D: Variation in maxillaty and mandibular molar and incisor vertical dimension in 12 year old subjects with excess, normal, and short lower anterior face height. Am J Orthod Dentofacial Orthop 106:409-418, 1994 35. Moiler E: The chewing apparatus. Acta Physiol 69:571574, 1966 36. lngervall B, Thilander B: Relationship between f~tcial morphology and activily of the mastecato D' muscles. J Oral Rehap 1:131-147, 1974 37. Vig KWL: Nasal obstruction and thcial growth: the strength of evidence for clinical assumptions. Am J Orthod Dentofacial Orthop 113:603-611, 1998 38. Fields HW, Warren DW, Black K, et al: Relationship between vertical dentofacial morphology and respiration in adolescents. Am J Ortho Dentofacial Orthop 99:147-154, 1991 39. Linder-Aronson S: Effects ofadenoidectomy on the dentition and facial skeleton over a period of five years, in Cook JT (ed): Transactions of the Third International Orthodontic Congress. St Louis, MO, Mosby, 1975 40. Woodside DG, Linde~Aronson S, Lundstrom A, et al: Mandibular and maxillmN growth after changed mode of breathing. AmJ Orthod Dento~acial Orthop 100:1-18, 1991 41. Proffitt WR: The etiology of orthodontic problems. Contemporary Orthodontics (ed 3). St. Louis, MO: Mosby, p 136 42. Schudy FF: The rotation of the mandible resulting from growth--Its implications in orthodontic treatment. The Vertical Dimension of the Human Face. Houston, TX: D Armstrong & Co, 1992, pp 151-179 43. Pearson LE, Pearson BL: Rapid maxillary expansion with incisor intrusion: a study of vertical control. Am J Orthod Dentofacial Orthop 115:576-582, 1999 44. Klontz HA: Facial balance and harmony: an attainable objective tbr the patient with a high mandibnlar plane angle. Am J Orthod Dentotacial Orthop 114:176-188, 1998 45. Vaden JL: Alternative uonsurgical strategies to treat complex orthodontic problems. Semin Orthod 2:90-113, 1996 46. Pearson LE: The management of vertical dimension problems in growing patients, from the enigma of the vertical dimension. In McNamara J A J r (ed): Craniofacial Growth Series 36, Center for Human Growth and Development. Ann Arbor, MI, The Universi~ of Michigan, 2000
he h u m a n face has been the subject of study since man could first express himself. As civilizations have risen and subsequently faded away, one thing that has remained is art, in most cases, drawings, paintings, and so on of faces. During the Renaissance, da Vinci, Michaelangelo, and D u h r e r led o t h e r artists to study faces. Facial p r o p o r t i o n was discovered; there were standards set for balance and h a r m o n y of the lower face. In our specialty of orthodontics, Angle was vitally c o n c e r n e d about the face. In his sixth edition, 1 he states, "One of the evil effects of malocclusion is the marring or distorting of the normal facial lines. It follows that, in the application of the principles of orthodontia, our efforts should be so directed as to mold and modify these lines of i n h a r m o n y to those of h a r m o n y and facial beauty so far as lies within the range of the possibilities of art, and of the type and t e m p e r a m e n t of the individual. O u r opportunities for benefiting humanity are very great in this field, far exceeding those offered by any other branch of dental science, for patients with facial lines so distorted as sometimes to be a marked deformity and a source of constant humiliation to themselves and their friends may
T
Prom the Department of Orthodontics, University of Tennessee, Memphis, TN; and a Private Practice, Edina, MN. Address cor~rspondence to James L. Vaden, DDS, M8, Department of Orthodonti~, University of Tennessee, Health Seienee Center, 875 Union Avenue, Memphis, TN 38163. Copyright 2002, Els~ier Science (USA). All rights trserved. 1073-8746/02/0803-0003535.00/0 doi:l O.1053/sodo. 2002.125431
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now be so treated as to bring about a complete transformation of the facial expression, even to the establishment of lines of beauty." Tweed revolutionized orthodontic diagnosis because of his c o n c e r n for the balance and harm o n y of the lower face. Many in our specialty have studied the face, z-6 developed diagnostic guidelines for quantifying facial balance, 7-u and proposed treatment regimens that give the orthodontic clinician a greater certainty that facial balance and h a r m o n y is an attainable goal for their patients. The underlying theme that surfaces from all artists and orthodontic investigators is the concept that there c a n n o t be good balance and h a r m o n y in the lower face unless the vertical dimension is within normal limits. The most important prerequisite for facial balance is a normal vertical dimension of the lower face. Poulton 12 c o n d u c t e d a study on cervical traction and f o u n d that large lower anterior facial heights were most often associated with a displeasing face. In their article on soft-tissue profile preference, DeSmit and DermauO 3 created three different series of nine profile photographs so that a total of more than 200 profiles could be ranked by graduate dental students. They f o u n d that differences in gender and orthodontic knowledge of the students seemed to have no significant influence on their esthetic preference. The results of their study confirmed the importance of anteroposterior deviations but suggested that unaesthetic facial profiles that were a result of anteroposterior deviations were completely overshadowed by long-face fea-
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Diagnosis of the Vertical Dimension
t u r e s - - t h e long-face feature being m o r e unaesthetic. Because of the challenge of the vertical dimension, the subject of this article is of extreme i m p o r t a n c e to the orthodontic specialist. Not only must the specialist recognize the problem, the specialist must u n d e r s t a n d the diagnosis of the p r o b l e m so that all facets and components of the vertical dimension e n i g m a are understood. T h e clinician must be able to recognize the various c o m p o n e n t s of a vertical dimension abnormality and u n d e r s t a n d the interrelationship of all the elements of the problem. Before discussing the abnormal, it is p r u d e n t to understand the normal. Two of the most accepted descriptions or publications of vertical facial proportions have b e e n published by Frakas 14 and Frakas and Munro. 15 In these, they describe the ideal face as vertically divided into equal thirds by horizontal lines that approximate the hairline, the bridge of the nose, the ala of the nose, and m e n t o n (Fig 1)J 6 Figure 1 also shows that in the ideal vertically p r o p o r t i o n e d face there is a further division of the lower one
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Figure 1. The ideal facial proportions as described by Frakas 14 and Frakas and Munro. 15 The frontal view of the face is divided into equal thirds by horizontal lines that approximate the hairline, the bridge of the nose, and the ala of the nose and menton. The lower third is further divided into an upper third and a lower two third.
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third of the face into an u p p e r one third and a lower two third. These divisions of the face can be used by the clinician to help diagnose vertical dimension problems. For example, does a patient have a disproportionately long lower facial height because of vertical maxillary excess or to excessive chin height? Conversely, is a short facial height caused by vertical maxillary deficiency or a short chin height? 17 By using these accepted proportions as a guide, the patient shown in Figure 2 has an excessive lower anterior facial height, whereas the patient shown in Figure 3 has diminished lower anterior facial height. Although it is evident that both have vertical dimension abnormalities by looking at the face, measuring the facial proportions confirms this intuitive conclusion. A careful determination of the vertical proportions of the face is therefore the first step in the diagnosis of a vertical dimension problem. Role of Skeletal and Dental Relationships After examining the face and quantifying its proportions, the skeletal pattern and the teeth and their relationships to each other must be scrutinized. However, a diagnosis of the vertical dim e n s i o n is m o r e complicated because vertical discrepancy malocclusions are nmltidimensional. For example, dentoalveolar abnormalities can impact the skeletal pattern, and p o o r skeletal patterns can cause dentoalveolar compensations that are difficult for the clinician to correct. T h e following variations can be present, either alone or in combination: (1) maxilla: maxillary posterior alveolar excess and inferiorly positioned maxilla and (2) mandible: mandibular posterior alveolar excess and short mandibular rami. O t h e r abnormalities may include superiorly positioned condylar fossa, obtuse cranial base angle, and condylar resorption. Any of these conditions, with or without aberrant m a n d i b u l a r growth rotation, can be a causative factor in the vertical discrepancy malocclusion. Condylar
Growth
A c o m m o n scenario affecting the skeletal problem is m a n d i b u l a r growth a n d growth rotation, which unfavorably impacts dentoalveolar devel-
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Figure 2. An example of a patient with an excessive lower facial height. o p m e n t in both the maxilla and mandible. Bjork is-21 and Bjork and Skieller 2:~,24 have perf o r m e d n m n e r o u s studies that have shown that the most c o m m o n direction of condylar growth is vertical, with some anterior c o m p o n e n t . Patients with a p r o n o u n c e d short lower anterior facial height (Fig 4A and B) generally exhibit upward and forward condylar growth (Fig 5). These individuals generally have a d e e p vertical overbite with a d e e p mentolabial sulcus and a strong overclosed appearance. 25 In contrast, pa-
Figure 3. An example of a patient with a diminished lower facial height.
tients with long-face syndrome (Fig 6A and B) have a m o r e posteriorly directed growth pattern of the m a n d i b u l a r condyle (Fig 7). 26,27 These backward growth rotators have increased anterior facial height, a m o r e posterior position of the chin, and in e x t r e m e cases, an anterior o p e n bite may develop. Serial images of the patient taken to m o n i t o r the direction of condylar growth would be very useful for the diagnosis of vertical growth. At the present time, serial imaging poses certain concerns, most significantly
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Figure 4. A patient with a pronounced short lower anterior facial height. (A) The cephalometric radiograph is also shown. (B)
radiation exposure. Advances in imaging technology may, in the future, p e r m i t the clinician to use these m e t h o d s for diagnostic purposes with greater safety. An understanding of the maxillomandibular growth rotation of the patient would be most helpful in the diagnosis of vertical variations. Bjork u8 has contributed information that offers some guidelines for the clinician to assist in the determination of the growth rotation of the mandible so that the c o n c o m i t a n t vertical changes are m o r e easily understood. Bjork's
m e t h o d of prediction of condylar growth rotation from a c e p h a l o g r a m offers the clinician some guidelines. Bjork identified seven specific structural features that m i g h t develop as a result of r e m o d e l i n g during a particular type of growth rotation. Bjork's suggestions for predicting condylar rotation have, however, not b e e n widely used by the specialty because (1) some of the indicators cannot be easily seen on the average cephalogram, (2) the use of the indicators is vmT time-consuming for the clinician, and (3) there has b e e n no scientific validation of the suggested
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the backward rotator exhibits (1) a straight inclination of the condyle, (2) a relatively straight mandibular canal, (3) the symphysis slopes forward and, (4) lower anterior facial height is long. Isaacson, 29 Isaacson et al, 3° and Schudy, ~ following on Bjork's reports, studied jaw rotation caused by vertical condylar growth. A succinct summary of the findings of these investigators is that a forward mandibular rotation occurs when vertical condylar growth exceeds the sum of the vertical growth of the maxillary sutures and the maxillary and mandibular alveolar processes. If growth of the maxillary sutures and the maxillary/mandibular alveolar processes exceeds vertical condylar growth, a backward rotation occurs, and the face becomes longer. An understanding of the effect of condylar growth on mandibular position is fundamental if the clinician is to adequately and appropriately diagnose a vertical dimension abnormality.
Figure 5. An example showing upward and forward condylar growth. indicators because of difficulties e n c o u n t e r e d in study design. Some in the specialty also question whether several of the suggestions are valid indicators of a particular type of growth rotation. However, when used for their intended purpose, as guidelines only, the indicators have some useful clinical applications in the diagnosis of the patient with vertical dysplasia (Table 1). Using Bjork's guidelines, it is interesting to study Figures 4B and 6B. Figure 4B, the forward rotator, exhibits several of Bjork's indicators including observations that (1) the condylar head curves forward, (2) the mandular canal is curved, (3) the symphysis has a backward cant, (4) the interincisal angle is obtuse and, (5) lower anterior facial height is short. Figure 6B,
Anterior and Posterior Facial Height Vertical dimension skeletal abnormalities are not solely caused by condylar growth direction. They are also caused by differences in anterior facial height and posterior facial height development. These differences in height development can lead to rotational growth or to changes in mandibular position that greatly influence the position of the chin. ~° Etiologies influencing unfavorable differences in development of anterior and posterior facial height are nmltifactorial. These factors can, for simplicity, be subdivided into those caused by (1) dentoalveolar developm e n t and (2) environmental factors.
Dentoalveolar Development Issacson et al 3~ studied dentoalveolar developm e n t in three groups of subjects--those with
Table 1. Bjork's Seven Structural Guidelines 2s
Inclination of the condylar head Curvature of the m a n d i b u l a r canal Shape of the m a n d i b u l a r lower border Inclination o f the symphysis (Anterior aspect j u s t below "B" point) Interincisal angle l n t e r p r e m o l a r or intermolar angles Anterior lower face h e i g h t
Fo~t~ard Pvotator
Backward Rotator
Cupees forward a n d back Curved Curved downward Slopes backward Vertical or obtuse Vertical or obtuse Short
Straigbt or slopes u p Straight Notchcd Slopes fi)iveard Acute Acute Tall
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Figure 6. An example of a patient with long-face syndrome. short anterior facial height, those with average anterior facial height, and those with excessive anterior facial height. T h e a m o u n t of maxillary posterior alveolar d e v e l o p m e n t was t o u n d to decrease as the MP-SN angle decreased. In patients with long anterior facial height (high MP-SN angles), the m e a n distance f r o m the occlusal plane to the inferior edge of the palate was 22.50 m m . This distance decreased to 19.6 m m for the average g r o u p and 17.1 m m for the g r o u p with
short anterior facial height (low MP-SN angles). This difference of 5.1 m m of dentoalveolar dev e l o p m e n t between the high angle and low angle groups is of significance. M a n d i b u l a r p o s t e r i o r alveolar d e v e l o p m e n t similarly d e c r e a s e d with decreases in the MP-SN angle b u t m u c h less dramatically t h a n those f o u n d in the maxilla. M a n d i b u l a r h e i g h t showed a m e a n of 31.2 m m for the l o n g anterior face h e i g h t g r o u p , 28.2 for the average
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Figure 7. An example showing a posterior-directed growth pattern of the mandibular condyle.
group, a n d 28.3 for the s h o r t a n t e r i o r face h e i g h t group. The findings of the Issacson et a133 study were confirmed in a study p e r f o r m e d by J a n s o n et al. 34 These investigators f o u n d that all dentoalveolar heights were significantly greater in long anterior facial height patients than in patients with n o r m a l facial height. Also, in the short lower anterior facial height, all dentoalveolar heights were significantly shorter than in the n o r m a l lower anterior facial height group. T h e differences in dentoalveolar development, most particularly in the maxilla, have a significant impact on the anterior facial height of the orthodontic patient. Moller and Ingerval135 and T h i l a n d e r :~6 have postulated that excessive maxillary posterior dentoalveolar develo p m e n t is associated with weaker masticatory musculature in high-angle patients c o m p a r e d with the strong musculature c o m m o n l y associated with short anterior facial height patients.
Enviornmental Role--Swallowing and Tongue Posture T h e role of tongue posture, swallowing, and breathing are still subjects of debate, argument, and study in orthodontics. Their respective impact on the vertical dimension are in n e e d of continued study and research.
Mouth breathing. T h e relationship between m o u t h breathing, altered posture, and the dev e l o p m e n t of malocclusion is not as clear cut as the theoretical o u t c o m e of shifting to oral respiration m i g h t a p p e a r at first g l a n c e Y Recent experimental studies have only partially clarified the situation. C u r r e n t e x p e r i m e n t a l data for the relationship between malocclusion and m o u t h breathing are derived f r o m studies of the nasal/ oral ratio in normal versus long-face c h i l d r e n Y T h e data from the study show that both normal and long-face children are likely to be predominantly nasal breathers u n d e r laboratory conditions. A minority of the long-face children had less than 40% nasal breathing, whereas n o n e of the normal children had such low nasal percentages. W h e n adult long-face patients are examined, the findings are similar: the n u m b e r with evidence of nasal obstruction is increased in comparison to a n o r m a l population, but the majority are not m o u t h breathers in the sense of p r e d o m i n a n t l y oral respiration. Airway problems, such as large adenoids, tonsils, or blocked ail~vays caused by septum deviations, large conchae, or allergies are frequently observed in high-angle patients and may affect m a n d i b u l a r posture, allowing m o r e f r e e d o m for posterior eruption. This hypothesis is s u p p o r t e d by Linder-Aronson 39,4° who showed closing of the m a n d i b u l a r plane angle and reduction in the anterior face height after removal of adenoids and tonsillectomy. It appears that research on respiration, up to the present time, has resulted in two opposing views: (1) total nasal obstruction is highly likely to alter the pattern of growth and lead to malocclusion in e x p e r i m e n t a l animals and humans, and individuals with a high p e r c e n t a g e of oral respiration are overrepresented in the long-face population, but (2) the majority of individuals with the long-lace pattern of deformity have no evidence of nasal obstruction and must therefore have some o t h e r etiologic factor as the principal cause. In conclusion, it appears that m o u t h breathing may contribute to the d e v e l o p m e n t of orthodontic p r o b l e m s but is difficult to indict as a frequent etiologic agent. Clinically, most orthodontists refer m o u t h breathers to an otolaryngologist tbr an evaluation. This p r o b l e m should be carefully evaluated during the diagnosis of a patient with excess vertical dimension.
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Swallowing and tongueposture. O n e viewpoint holds that t o n g u e thrust swallowing is seen in (1) y o u n g e r children with r e a s o n a b l y n o r m a l occlusion in w h o m it r e p r e s e n t s only a transitional stage in n o r m a l physiologic m a t u r a t i o n a n d (2) in individuals who have displaced incisors. In the latter, it is an a d a p t a t i o n to the space b e t w e e n the teeth. O t h e r s a r g u e that t o n g u e thrust swallowing simply has too s h o r t a d u r a t i o n to have an i m p a c t o n t o o t h position. Pressure by the t o n g u e against the teeth d u r i n g a typical swallow lasts for a p p r o x imately 1 second. A typical individual swallows a b o u t 800 times p e r day while awake b u t has only a few swallows p e r h o u r while asleep. T h e total p e r day, t h e r e f o r e , is usually u n d e r 1,000. O n e t h o u s a n d seconds of pressure, of course, totals only a few minutes, n o t nearly e n o u g h time, it is argued, to affect the equilibrium. 41 Most clinicians believe that if a patient has a forward resting posture of the tongue, the duration of this pressure, even if very light, could affect tooth position, vertically or horizontally. Tongue-tip protrusion during swallowing is sometimes associated with a forward tongue posture. During the diagnosis of the patient with a vertical dimension problem, the clinician must u n d e r s t a n d that condylar growth, sutural lowering of the maxillary complex, dentoalveolar development, dental eruption, and the patient's oral e n v i r o n m e n t / h a b i t s are interrelated. T h e r e is not generally a single causative factor that predisposes the patient to too m u c h or too little vertical d e v e l o p m e n t of lower facial height. To simplify, one might conclude as a general rule, that when vertical condylar growth exceeds tooth eruption (alveolar development), forward m a n d i b u l a r rotation occurs. T h e result is increased posterior facial height a n d an increase in the ratio of posterior facial height to anterior facial height. Conversely, if dentoalveolar growth and tooth eruption are greater than vertical condylar growth, the resultant m a n d i b u l a r change is backward rotation. T h e anterior facial h e i g h t / p o s t e r i o r facial height ratio decreases. 42 Environmental factors can play a role, but the role is, at times, difficult to assess and varies f r o m patient to patient.
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Diagnostic Considerations Steep Excess Vertical Pattern: The Backward Rotator During differential diagnosis of the high-angle patient, two questions must be asked. First, where should the teeth be positioned? For the patient with long anterior facial height, the mandibular anterior teeth are most often positioned in a m o r e retracted posture over basal bone. Lip p r o c m n b a n c y can be best resolved if the mandibular anterior teeth are upright. T h e a m o u n t of uprighting that must be achieved is a matter of (1) clinical preference and must be determ i n e d during the t r e a t m e n t p l a n n i n g phase of the t r e a t m e n t protocol or (2) the dictates of the malocclusion. If indeed the facial profile of the patient with excess vertical dimension is long, a vertical reduction genioplasty can be effective for facial esthetics. It is f u n d a m e n t a l for the clinician to be able to visualize the posttreatm e n t positions of the m a n d i b u l a r anterior teeth during t r e a t m e n t plan preparation. Secondly, will extractions be necessary? For m a n y patients with excessive lower anterior facial height, extractions may be necessary. T h e question of which teeth should be extracted can be answered only after a t h o r o u g h and accurate differential diagnosis.
The Overdosed Forward Rotator Patients with short anterior vertical facial height have a unique set of problems that require different diagnostic considerations. The following diagnostic guidelines should be considered when a patient with this skeletal pattern is treated without surgical intervention. Mandibular incisors, if well aligned before treatment, can be allowed to remain in their p r e t r e a t m e n t position. Uprighting of mandibular incisors has an adverse impact on facial esthetics of the low-angle patient. However, the m a n d i b u l a r incisors, if malaligned, should not be proclined beyond their bony support for the p u r p o s e of alignment. Some overclosed forward rotator malocclusions are characterized by a d e e p vertical overbite, maxillary incisor protrusion, a n d / o r crowding. Correction of the overbite for these patients is best accomplished by intrusion and retraction of the maxillary incisors.
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Treatment Concerns During the diagnosis of the vertical dimension problem, the clinician must be attentive to the force systems that are p l a n n e d for treatment and understand that undesirable reactions to incorrectly applied fbrce systems are disastrous. Posterior facial height must be carefully controlled for the high-angle patient because an increase in posterior facial height will result in an increase in anterior facial height. 434~ An increase in anterior facial height of high-angle patients is calamitous. An important mechanical tooth manipulation that must be accomplished during the treatment of the patient with excess vertical dimension is prevention of extrusion of the mandibular posterior teeth, assuming that the maxillary posterior vertical dimension is controlled by intrusive forces (ie, headgear or other methods). Extrusion in the molar areas will prevent successful correction of the malocclusion with excess vertical dimension and long lower anterior t:ace height. It is important for the clinician to understand these concepts during diagnosis and treatm e n t planning so that extraoral traction can be planned to help control the vertical dimension during treatment. There should be intrusive forces to the posterior segments of both arches. Additionally, Class II elastic wear can be one of the most detrimental force applications that is applied to a patient with long lower anterior facial height. If Class II elastics are used indiscriminately on the high-angle patient, the mandible drops down and back and increases the sagittal discrepancy. Therefore, Class II elastic use, or the absence of it, must be planned for during diagnosis and treatment planning. Pearson 4~ has published his results using vertical pull chin cups and has provided evidence that their use can create some effective skeletal changes for the long-face patient. A thoughtful diagnostician nmst consider the use of whatever means is necessary to impact treatment and prevent the lengthening of lower anterior facial height during the course of treatment.
Summary The orthodontic clinician must make a careful differential diagnosis for each patient who seeks his or her care. The diagnosis must analyze all
three c o m p o n e n t s of a malocclusion facial, dental, and skeletal. Each c o m p o n e n t must be carefully studied and u n d e r s t o o d so that (1) the p r o p e r questions are asked and (2) the correct diagnostic decisions are made to lead to an effective treatment plan. Diagnosis of the vertical dimension is a con> plex problem. Yet, it can be as simple as studying a face and applying c o m m o n sense diagnostic tools to ascertain the reason that the lower face is too long or too short. The vertical dimension has been a subject of study and debate since orthodontics became a specialty. Researchers in the field of vertical dimension diagnosis, including Bjork, is Schudy, 27 Nielsen, 25 Isaacson, 29 Pearson, ~6 and others, have provided the specialty many useful guidelines and concepts that can be used by every orthodontic clinician as they diagnose a malocclusion that is complicated by a vertical dimension discrepancy. Orthodontists should continue to use the work of these researchers and clinicians for a foundation as more studies are u n d e r t a k e n that will yield more knowledge so that diagnosis of the vertical dimension becomes less art and more science.
References 1. Angle EH: Malocclusion of the T e e t h a n d Fractures of the Maxillae (ed 6). Philadelphia, PA, SS "v~qlite Co, 1900, p 15 2. Tweed el: Indications for the extraction of teeth in orthodontic procedure. Am J O r t h o d 30:405-428, 1934 3. Peck H, Peck S: A concept of facial esthetics. Angle O r t h o d 40:284-317, 1970 4. Burstone CJ: Lip posture a n d its significance in treatm e n t planning. A m J O r t h o d 53:262-284, 1967 5. Hulsey CM: An esthetic evaluation of lip-teeth relationships present in the smile. A m J O r t h o d 57:132-144, 1970 6. Peck S, Peck L: Selected aspects o f the art a n d science of facial esthetics. Semin O r t h o d 1:105-126, 1995 7. Merrifield LL: T h e profile line as an aid in critically evaluating facial esthetics. A m J O r t h o d 52:804-821, 1966 8. Czarnecki ST, N a n d a R, Currier F: Perceptions o f a balanced Facial profile. A m J Orthod, Dentnt~tcial Orthop 104:180-187, 1993 9. Ricketts RM: Divine proportions in facial esthetics. Clin Plastic Surg 9:401-422, 1982 10. Steiner CC: Cephalometrics tor you a n d me. A m J Ortfiod 39:729-755, 1953 11. Holdaway RA: A soft tissue analysis a n d its use in orthodontic t r e a t m e n t planning: Part I. Aau J O r t h o d 84:128, 1983 12. Poulton DR: T h e influence of extraoral traction. A m J O r t h o d 53:8-18, 1967 13. DeSmit A, D e r m a u t L: Soft-tissue profile preference. A m J O r t h o d 86:67-73, 1984
Diagnosis of the Vertical Dimension
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