CE Approaches to Vertical Dimension - spearaesthetics.com · reduce the excessive tooth and...

2 Advanced Esthetics & Interdisciplinary Dentistry Vol. 2, No. 3, 2006

In dentistry there are areas of inter-est that provoke heated debate

among different groups of practi-tioners. Vertical dimension is one ofthose topics. There are practitionerswho vehemently defend their positionas to how vertical dimension shouldbe established, whether it can be mod-ified, and what the outcome will beif it is modified incorrectly. Otherpractitioners hold the exact oppositebeliefs with equal intensity. These dif-ferences of opinion become confusing,because most clinicians are searchingfor the right answer with regard tohow patients should be treated. As ageneral rule, any time multiple dif-ferent approaches exist for a longperiod of time in dentistry, it is proba-bly because there are several correctanswers to the same problem. Aswe will see, that is the case with verti-cal dimension.

Understanding OcclusalVertical Dimension

The Glossary of Prosthodontic Termsdefines “occlusal vertical dimension” asthe distance between any point on themaxilla and any point on the mandiblewhere the teeth are in maximum inter-cuspation. Commonly, nasion and men-ton are used for these points.

Vertical Dimension duringGrowth and Development

Three factors affect the occlusalvertical dimension during growth anddevelopment: the growth of the ramus,

the gonial angle of the mandible, andthe eruption of the teeth. As the ramusgrows, the teeth continue to erupt, main-taining the occlusion. There can be,however, significant differences in thelength of the ramus, which has a sig-nificant impact on anterior facial heightor “vertical dimension.” In what wouldbe considered normal or ideal ramusdevelopment, the midface, measuredfrom glabella to the base of the nose, isroughly equal in measurement to thelower face measured from the base ofthe nose to the bottom of the chin atthe completion of growth. As ramuslength varies, both anterior facial heightand tooth display vary. Differences inramus length are primarily influencedby genetic variations.1-11 A patient whohas a short ramus with normal posteriortooth eruption will have an increasedanterior facial height and an anterioropen bite. Often, however, the anteriorteeth in such a patient overerupt tomaintain the occlusion, creating bothexcessive tooth and gingival display.Commonly, the patient with a shortramus shows a long lower facial heightwhen compared with their midfacialheight. This patient has excessive gingi-val display and is often treated with amaxillary impaction to decrease theirvertical dimension (Figures 1 and 2).12-16

A patient who has a long ramus withnormal posterior tooth eruption willhave the opposite facial appearance tothat of the person with a short ramus.Commonly, this patient will have avery short lower face in comparison to

Approaches to Vertical Dimension

Frank M. Spear, DDS, MSDFounder and Director

Seattle Institute for AdvancedDental Education

Seattle, Washington

Affiliate Assistant ProfessorUniversity of Washington

School of DentistrySeattle, Washington

Private PracticeSeattle, Washington

Learning Objectives

After reading this article, thereader should be able to:

• explain how vertical dimensionis established during growthand development.

• discuss the five most commonconcerns of practitioners whenconsidering an alteration of vertical dimension.

• describe the different beliefsabout how vertical dimensionshould be established.

Abstract: Vertical dimension is a highly debated topic in dentistry. Differences of opinion over howvertical dimension should be established, whether it can be modified, and what the outcome ofmodification will be can become confusing for those dentists searching for the right treatment for theirpatients. The fact is that there are multiple different approaches because there are several correct waysto alter vertical dimension. This article will address the most common reasons dentists consider alteringvertical dimension, their five top areas of concern, and the methods by which vertical dimension canbe established.

CE

CE

their midface and may have inade-quate maxillary tooth display. Unlikethe long, slender face of the shortramus patient, the long ramus patientmay have a very square face (Figures 3and 4). Treatment of the vertical dimen-sion of the long-ramus patient ofteninvolves a double jaw surgery to rotatethe chin inferiorly as well as the maxil-la to increase lower facial height andincrease maxillary tooth display. Thissurgery has the impact of lengtheningthe overall face and increasing thepatient’s vertical dimension while at thesame time maintaining the length ofthe ramus or overall posterior verticaldimension.17-22 The patient’s gonialangle also has an impact on the patient’santerior vertical dimension. A patientwith an acute gonial angle has a ten-dency to mimic the facial features of apatient with a long ramus, with a squareface and short lower face compared totheir midface. These patients are com-monly referred to as having a flat man-dibular plane angle. Patients who havemore obtuse gonial angles mimic theappearance of patients with short ramusheights, with a long narrow face, exces-sive tooth and gingival display, and along lower face when compared to theirmidface. Patients with more obtusegonial angles often are referred to ashaving steep mandibular plane angles.There appears to be some evidence thatthe formation of the gonial angle maybe influenced by the strength of themasseter muscle. The stronger and moredeveloped the masseter muscle is, themore pronounced or acute the gonialangle is (Figure 5).22,23 In addition toramus length and gonial angles, tootheruption plays a critical role in thedevelopment of a patient’s verticaldimension. In normal growth anddevelopment, the maxillary and man-dibular teeth erupt to maintain occlusalcontact as the face grows. There can bevariations, however, in tooth eruptionthat can result in alterations in facialvertical dimension. After growth iscompleted, tooth eruption is necessaryto maintain the vertical dimension ifany wear occurs. If eruption occurs atthe same rate as tooth wear, the verti-cal dimension of the patient will beunchanged. If, however, the eruptiondoes not keep up with tooth wear, the

Figure 1—A patient with a short ramus exhibiting a long anterior facial height, excessive tooth andgingival display, and a significantly longer, lower face than midface. The patient shows 8 mm of toothat rest, 5 mm more than would be normal for her age.

Figure 3—A patient with a long ramus. Note the reduced anterior facial height and very square facialappearance.

Figure 2—Before and after photographs of the patient seen in Figure 1 after a maxillary impaction toreduce the excessive tooth and gingival display and reduce the vertical dimension.

Figure 4—Before and after photographs of the patient seen in Figure 3 after double-jaw surgery torotate the mandible and the maxilla inferiorly, increasing tooth display and anterior facial height.

Vol. 2, No. 3, 2006 Advanced Esthetics & Interdisciplinary Dentistry 3

vertical dimension may decrease withtime. The question of whether eruptionkeeps up with tooth wear to maintainvertical dimension is one of the mostheated debates in dentistry.24-27

Clinical Alterations ofVertical Dimension

Having described how vertical di-mension is established during growthand development, it is now importantto discuss why vertical dimension mightbe changed clinically. The most com-mon reasons dentists consider alteringvertical dimension are: 1) to improveesthetics by altering facial form and/ortooth and gingival display; 2) to improveocclusal relationships, such as correctinganterior open bites; and 3) to gain spacefor the restoration of short or worn teeth.Practitioners often mention five areasof concern about altering vertical dimen-sion. Will the vertical alteration have anegative effect on the temporal mandibu-lar joint? Will muscle pain be a sideeffect of the change in vertical dimen-sion? Will the vertical dimension bestable in its new position? Will muscleactivity levels be altered, increasingbite force and potentially increasingthe failure rate of restorations? Willspeech be affected in a negative way?

Effects on the TemporalMandibular Joint

To address these concerns, it is help-ful to evaluate the literature on thealteration of vertical dimension and itsimpact in each of the five areas. Withregard to pain in the temporal mandibu-lar joint, the literature is clear that ifthe joint is comfortable at the existingvertical dimension, it is highly unlikelythat the joint will experience any discom-fort at an altered vertical dimension. Itis possible, however, in the event ofanterior disc displacement, that alter-ing vertical dimension may change therelationship of how the condyle com-presses retrodiscal tissue posterior tothe displaced disc (Figure 6). In someinstances, increasing the vertical dimen-sion may benefit the relationship ofthe condyle to the disc, whereas in oth-er circumstances it is possible that achange in vertical dimension may havea negative effect. If the patient is havingsignificant joint symptoms, it will benecessary to try out any vertical changesin an appliance to predict the impact ofthe vertical dimension on the patient’ssymptoms. It is critical that when thevertical dimension is altered, there arestable posterior occlusal contacts, be-cause a lack of posterior occlusion cansignificantly increase the load on thejoints. Alterations in vertical dimensiondo not have a negative impact on tem-poral mandibular joints unless the jointsuffers from an internal derangement.Even then there is a high likelihoodthat a vertical alteration will not nega-tively affect the joint.28-31

Muscle PainThe next area of concern in alter-

ing vertical dimension is the impact

regarding muscle pain. When evaluatingthe literature it is prudent to examinehow the research was done. There areseveral papers that have concluded thataltering vertical dimension producessymptoms such as headaches, muscleaches, and muscle fatigue.32-34 Theproblem with several of these researchprojects is that they altered verticaldimension by building up only theposterior teeth without any anteriorcontact or anterior guidance. At theend of the study, several of the patientsreported muscle symptoms and it wasconcluded that it was a result of thechange in vertical dimension. In fact,the patients were left with an occlusalscheme that would not be created clini-cally. If the articles regarding the impactof vertical dimension changes on mus-cles are limited to those that createdan ideal occlusal scheme simply at dif-ferent vertical dimensions, it is clearthat altering vertical dimension does notproduce muscle pain. In fact, less than5% of the patients had any short-termmuscle awareness, which disappeared2 weeks after the vertical alteration.35-40

Stability of Altered Vertical Dimensions

Another area of concern that gen-erates heated debate is the stability of thevertical dimension after any changes.Two basic schools of thought exist. Onebelieves that any change in verticaldimension will be followed by a returnto the previous vertical dimensionthrough tooth intrusion or tooth erup-tion. This group believes that the lengthof the masseter muscle and medialpterygoid are fixed and, therefore, anyalteration in the vertical dimension ofocclusion will revert back to the previous

Figure 6—This illustration shows how thecondyle compresses retrodiscal tissue afteranterior disc displacement.


Figure 5—The impact of ramus length and gonial angle on lower facial height and mandibular plane angle. Note the reduced lower facial height in theexample with a long ramus and flat angle, and the exaggerated lower facial height in the example with the short ramus and steep angle.

CE

vertical dimension because of the fixednature of the muscles (Figure 7). Thesecond group believes that verticaldimension is adaptable and that changesin the vertical dimension of occlusionare maintained because of an alterationin the length of the muscles. The factthat these arguments between the twogroups have gone on for decades shouldgive us some clue as to the confusionregarding stability.

It may be that both groups are cor-rect some of the time. The literaturedefinitely shows examples of a relapsetoward the original vertical dimensionoccurring after an alteration in verticaldimension. This relapse could be anincrease in vertical dimension after asignificant closing of the vertical dimen-sion, which might occur after maxil-lary impaction surgery. However, therelapse in these circumstances may beonly a small percentage of the actualchange that occurred.41-43 Conversely,certain clinical procedures may be asso-ciated with significant relapse, such asdown-fracturing the maxilla to increasetooth display and facial height in thepatient with a long ramus and squareface. Immediately after surgery, thevertical change may look excellent, butstatistically these patients experiencesignificant relapse.44-46 It is for thisreason that today these patients are treat-ed with double-jaw surgery, because theposterior portion of the mandible,including the insertion of the masseterand medial pterygoid muscle, is notaltered during the surgery. Instead, thebody of the mandible and the maxillaare rotated inferiorly to improve toothdisplay and facial height while maintain-ing the length of the muscles (Figure 8).

This surgical approach has provenvery stable.

The two previous examples involvedorthognathic surgery and significantalterations to vertical dimension. Liter-ature searches on more traditional meth-ods of altering vertical dimension, suchas through the use of restorative den-tistry, do not show clear conclusionswith regard to stability. Some articlesshow very little or no relapse occur-ring, whereas others indicate a moresignificant relapse occurring. In someinstances, the patients with the high-est percentage of relapse were thosethat had the smallest actual change invertical dimension.47-52

The reason so much confusion existsregarding stability may in fact have todo with the geometry of the temporalmandibular joint, masseter muscle,medial pterygoid muscle, and anteriorteeth. Most alterations to vertical dimen-sion are measured at the anterior teeth,with a 3-mm alteration in anterior ver-tical dimension resulting in less than1 mm of change in masseter musclelength. Additionally, if the condyle isseated in the fossa of the temporalmandibular joint during treatment,for each millimeter the condyle is seatedvertically the masseter muscle length isreduced almost 1 mm. It is, therefore,possible that if the condyle is seated as theanterior vertical dimension is increased,there will be minimal, if any, change inmasseter or medial pterygoid musclelength, and there would be no expec-tation of relapse (Figure 9). However,if there was no alteration in the verticalposition of the condyle as the anteriorvertical dimension was increased, achange in muscle length would have

Figure 8—A superimposition of the before andafter cephalometric radiographs from thepatient in Figures 3 and 4. There has been nochange in molar position but a 5-mm inferiormovement of the chin has increased the anteri-or vertical dimension without changing theposterior vertical dimension.


Figure 10—Three stages in the treatment of a patient whose vertical dimension was increased. At the far left is the pretreatment vertical dimension. Themiddle shows the provisional restorations 6 months postinsertion. The far right shows 5 years after seating of the final restorations. It appears that duringthe 4.5 years between the middle photograph and the right photograph no change has taken place in terms of vertical relapse. However, it is possible hadthis patient been monitored with cephalometric radiographs for some relapse to have occurred in the distance between the maxilla and the mandible with-out the patient or the clinician realizing it, and with the occlusion remaining the same.

Figure 9—This illustration shows the geometryrelating increases in anterior vertical dimensionto decreases in posterior vertical dimensionfrom the seating of the condyle.

Figure 7—This illustration shows how the mas-seter muscle is related to anterior verticaldimension via its insertion points on the maxillaand the mandible.

occurred, and may be responsible forany relapse.

Because none of the studies47-52

assessed the change in condylar posi-tion and related it to the alteration inanterior vertical dimension, it is impos-sible to make that conclusion. The realquestion concerning stability is whatclinical impact any relapse would haveon the patient. It would appear thateven in the studies where some relapseoccurred, the patients involved werebasically unaware of the relapse andexperienced no symptoms. Unless anoperator was evaluating vertical dimen-sion using radiography, the clinicianwould not see any changes posttreat-ment (Figure 10). The conclusion con-cerning stability is that it is an unknownentity; that is, the patient may or maynot experience some relapse, but thetreatment will remain successful.

Impact on Muscle Activity LevelsThe fourth area of concern when

altering vertical dimension is the impacton muscle activity levels. There aretwo components to the activity levelsof muscles: the muscle activity levelwhen the mandible is at rest and themuscle activity level when the patient

is clenching. As the vertical dimensionis increased, resting muscle activityactually decreases. The more open thevertical dimension is, the less activityis present in the muscles in a posturalposition. This decrease in muscle activi-ty occurs until there is approximately10 mm to 12 mm of anterior verticalopening. Opening beyond 10 mm to12 mm starts to increase elevator muscleactivity. Interestingly enough, if thevertical change is maintained for 3 to4 months, the resting muscle activityreturns to a level closely matching thepretreatment resting muscle activitylevel, although the vertical dimensionhas not been decreased.53-56

The impact of increasing verticaldimension on clenching muscle activityis the opposite; as the vertical dimensionis increased, the electrical activity levelin the elevator muscles increases duringclenching beyond their pretreatmentlevel. Again, however, if the verticaldimension is maintained for 3 to 4months, this increased level of clenchingelectrical activity similarly reduces topretreatment levels.57-60 In summary,although there is an initial change bothin resting and clenching activity levels,after 3 to 4 months at the new vertical

dimension, the muscle activity is similarto pretreatment levels. This is a criticalfinding because any treatment thatattempts to modify muscle activity levelsby altering vertical dimension can onlybe successful on a short-term basisbecause of the body’s natural neuro-muscular adaptability.

Effects on SpeechThe final area of concern when

altering vertical dimension concernsphonetics, particularly the sibilant or“S” sounds. As a general rule, there is ahigh level of adaptability by mostpatients with regard to speech. After ashort period of time, usually 1 week to4 weeks, most patients will learn toreprogram their speech patterns to anyalterations that have been made den-tally. There are, however, patients inwhom this adaptation does not occur.To understand how this might be relat-ed to vertical dimension it is importantto understand the differences in howpatients make sibilant sounds. Themajority of people make “S” soundsby moving their mandible forward sothat the incisal edges of the mandibularincisors are end-to-end with the incisaledges of the maxillary incisors (Figure11). For these patients, it is the incisaledge position of the teeth that can cre-ate phonetic problems if a significantincrease in incisal ledge length occurredto either the maxillary or mandibularincisors. The teeth may now collideduring the “S” sounds, generally result-ing in a whistling or slurring any timea sibilant sound is made. This can beevaluated clinically by simply havingthe patient say “66” or “77” and watch-ing to see if the anterior teeth touchduring the sibilant sound. If they do,and the patient has been given 2 to 4weeks to adapt and has not, it will benecessary to shorten either the upper orthe lower incisor. If the upper incisorcan be shortened it is possible to cor-rect the phonetics and not alter thecentric occlusal contacts at all. However,although it is possible to shorten thelower incisor to correct speech, it isnecessary to remove the centric con-tact on the lingual of the maxillaryincisor. If the centric contact can begained by adding material to the lin-gual of the maxillary incisor, vertical

Figure 11—Patients use different methods to create sibilant sounds. On the far left is the intercuspalposition. In the middle, a patient makes sounds using the lingual of the maxillary incisors. On the farright is a patient who postures the mandible forward, making sibilant sounds between the maxillaryand mandibular incisal edges.

Figure 12—On the left is the patient seen in Figure 10, 1 month after the provisional restorations hadbeen placed, increasing the vertical dimension. On the right is this patient saying “66” and lispingduring sibilant sounds. It was necessary to reduce the mandibular incisors to correct phonetics.



dimension will not be affected. However,if it is not possible to add material on thelingual of the maxillary incisor, it willbe necessary to either close the verticaldimension to regain centric contactrestoratively or leave the patient with ananterior open bite, risking secondaryeruption and instability (Figure 12).

The second method by whichpatients make sibilant sounds is betweenthe mandibular incisal edge and thelingual contour of the maxillary inci-sors. If vertical dimension has beenincreased restoratively in these patients,any problems with phonetics will bebetween the mandibular incisal edgeand the lingual contour of the maxil-lary incisors. Again, if after 2 to 4 weeksof adaptation the patient is still havingdifficulty making “S” sounds, it willbe necessary to provide a speaking space.This can be done by shortening the low-er incisor or removing material fromthe lingual of the maxillary incisor. Ineither case, however, it is highly likelythat the centric contact will be removedand since the “S” sound is now madeon the lingual of the maxillary anteriorteeth, the only method to regain anteri-or contact is to close the vertical dimen-sion.61-65 In summary, with regard tothe five major concerns about alteringvertical dimension, it is obvious fromreviewing the literature that changes invertical dimension are well tolerated inthe majority of patients and there is noevidence that there is only one correctvertical dimension.

Determining a New Vertical Dimension

The next question that cliniciansfrequently ask is how to determine anew vertical dimension. Historically,several techniques have been used,many from denture prosthodontics.

Using Freeway SpaceThe first technique most dentists are

exposed to concerning vertical dimen-sion is the use of freeway space. Freewayspace is defined as the distance betweenthe maxillary and mandibular teethwhen the mandible is in its posturalposition. Several different techniqueshave been used to reproduce this pos-tural position, from having the patientsay “M,” to having them lick their

lips, swallow, and relax. Most schoolsadvise a 2-mm to 4-mm freeway spaceas normal, so if there is a desire toincrease the vertical dimension on adenture it is necessary that the patienthave more than 4 mm of freeway spacewith their existing dentures. The free-way space then determines how muchthe vertical dimension can be increased.This method of using freeway space todetermine vertical dimension has beenused for decades in denture prostho-dontics. It is important to note, how-ever, that freeway space is only beingused to mount the models and set theteeth for the denture try-in. At the try-in, phonetics and esthetics are used torefine final incisal edge position andvertical dimension. The challenge ofusing freeway space for patients whostill have their natural teeth is that asthe vertical dimension is changed; mul-tiple studies have found that freewayspace recreates itself within the subse-quent 4 weeks. Because of this, the useof freeway space to determine whethervertical dimension can be altered is notsupported by research for patients whostill have natural teeth.66-77

Trial AppliancesAnother method of determining ver-

tical dimension is the use of a trial splintor appliance. The patient is asked towear an acrylic appliance, typically for3 months, to evaluate if the new verticaldimension can be tolerated. The theorybehind this is that the patient will expe-rience pain if the vertical dimension isnot acceptable, but the challenge ofthis approach is that outside of a fewpatients with temporal mandibular jointproblems, altering vertical dimensiondoes not produce pain. Although theappliance may be very useful to deter-mine other elements of treatment orto aid in muscle deprogramming, itdoes not provide specific informationregarding vertical dimension.

Transcutaneous ElectricalNeural Stimulation

A third methodology that has alsobeen used for decades to determinevertical dimension is the use of tran-scutaneous electrical neural stimulation(TENS). In this approach, electrodesare applied over the coronoid notch

and a mild, cyclic electrical current isgenerated to stimulate contraction ofthe muscles of mastication by way of thecranial nerves. The surface electricalactivity of the temporalis, masseter, anddigastric muscles are recorded elec-tromyographically, and a jaw-trackingdevice evaluates the position of themandible relative to the maxilla. A base-line electromyographic reading is takenbefore any muscle relaxation. The TENSunit is then started to relax the musclesof mastication and the electrical activityof the muscles evaluated. Neuromus-cular rest is achieved when the elevatormuscles are at their lowest level of activ-ity without an increase in the electricalactivity of the digastric muscles. Thisneuromuscular rest position is thoughtto be the starting point for the buildingof the occlusion. The operator closesup from this position for the “new”amount of freeway space, effectivelyusing the combination of neuromuscu-lar rest and freeway space to determinethe new occlusal vertical dimension.The primary flaws of this approachrelate to the neuromuscular adaptabilityof patients. As discussed earlier, the rest-ing electrical activity of muscles, as wellas freeway space, relapse toward pretreat-ment levels from 1 month to 4 monthsposttreatment. Also, this approach oftenresults in a vertical dimension moreopen than the patient’s existing verticaldimension, which can lead to the needfor an extensive amount of restorativedentistry and extremely large teeth, sim-ply to accommodate the vertical dimen-sion that was dictated by the equipment.

Measurements Using theCementoenamel Junction

Another methodology that hasbeen described78,79 to determine ver-tical dimension is to measure from thecementoenamel junction (CEJ), or gin-gival margins of the maxillary centralincisors to the CEJ, or gingival mar-gins of the mandibular central inci-sors. This distance is then compared tothe 18-mm to 20-mm average distanceseen in a dentition of unworn teethand a class I occlusion. If this distance isless than 18 mm, it probably indicatesa loss of vertical dimension and is,therefore, a rationale for increasing it.The primary flaw of this approach is

CE

that the anterior teeth do not establishthe vertical dimension of occlusion; itis established by the length of the ramusand the eruption of the posterior teeth.Measuring the distance between theCEJ or gingival margins simply evaluatesthe amount of anterior tooth eruption,not the vertical dimension of occlusion.It is in fact possible to have an extremelydiminished CEJ-to-CEJ distance in theanterior and a perfectly normal verticaldimension of occlusion. This can occurcommonly in patients with severe ante-rior tooth wear and no posterior toothwear (Figure 13).80 Most cliniciansexamine the worn anterior teeth anddecide to open the bite to gain space forrestoration, when in fact by intrudingthe worn anterior teeth or crown length-ening them to correct the gingival lev-els the patient could be treated at theexisting vertical dimension (Figures 14and 15). As a general rule, if the poste-rior teeth are present, unworn, and inocclusion, it is highly unlikely that thepatient has lost vertical dimension. Ifthere is a lack of space to restore the

anterior teeth it is also likely that ortho-dontics or crown lengthening wouldallow the patient to be treated withoutthe need to treat their posterior teeth.

The Method of Facial ProportionAs discussed in the introduction,

facial proportion is another method thathas been described in the literature81,82

for determining vertical dimension. Inthis approach, the theory is that thevertical dimension of occlusion shouldbe created in a way that corrects facialproportion. In an ideal face, the midfaceand the lower face are approximatelyequal in height. The method of facialproportion alters the length of the lowerface to correspond to the length of themidface by altering the length of theteeth. Although this approach may beentirely appropriate for an orthog-nathic surgeon who has the ability ofmaking significant alterations in man-dibular position, it is extremely difficultfor an orthodontist or restorative den-tist to make large variations in verticaldimension that would influence facial

proportion and still allow a correctocclusal relationship. As the verticaldimension is increased or decreased,overjet is also altered significantly; foreach 3-mm vertical change in the anteri-or teeth, there is approximately a 2-mmhorizontal change in an anteroposteriordimension. This 2-mm change is analteration in overjet. Therefore, attempt-ing to increase the vertical dimension by6 mm will result in a 4-mm increase inoverjet, making it almost impossibleto have correct anterior occlusal contactunless the patient started out with aclass III occlusion. In addition to thisfundamental flaw regarding overjet, it isalmost impossible for the orthodontistor restorative dentist to correct facialproportion if the patient’s lower face isexcessively long and the vertical dimen-sion needs to be closed. Finally, in astudy evaluating whether dentists werecapable of seeing the facial differencescaused by changes in vertical dimen-sions of 2 mm, 4 mm, 6 mm, or 8 mm,Gross83 found that until the changereached 8 mm, dentists were unable toassess the difference in facial features.This is quite logical, as the only time apatient’s vertical dimension of occlu-sion is generally evaluated is when theirteeth are together; typically in most oflife’s activities the teeth are apart andtherefore not affecting facial proportion.In fact, it is the author’s belief that it isthe change in tooth display when verti-cal dimension is opened that dramati-cally alters a patient’s esthetics, not thefacial change because of the change invertical dimension.

Choosing the Right VerticalDimension for the Patient

After reviewing many of the differenttechniques for determining verticaldimension it is easy to see the flaws inall of them, and yet they all have beenused successfully, many of them fordecades. This means that vertical dimen-sion is a highly adaptable position, andthere is no single correct vertical dimen-sion. Furthermore, using a particularvertical dimension as the rationale toreconstruct teeth which otherwise donot need treatment is not scientificallyjustified. If the patient does need an ex-tensive reconstruction, several differentvertical dimensions could be successful.

Figure 13—On the left, a 29-year-old patient with minimal or no posterior wear but severe anteriorwear. On the right is the same patient in occlusion. Measuring from the gingival margins of the ante-rior teeth makes it appear as though the patient has lost a vertical dimension but this is an illusionbecause of the overeruption of the worn anterior teeth.

Figure 14—Initial and treatment photographs of the patient seen in Figure 13. The mandibular ante-rior teeth have been built up and then orthodontically intruded, creating space for restoration.

Figure 15—Before and after photographs of the patient seen in Figures 13 and 14. The patient wastreated with orthodontics and four maxillary incisors and four mandibular incisor full crowns. Nochanges were made to the patient’s vertical dimension.


This ultimately leaves us with the ques-tion of which one to choose. In answer-ing that question, and because manydifferent vertical dimensions may besuccessful, it makes the most sense tothe author to choose the one that sat-isfies the patient’s esthetic goals andthe clinician’s functional goals. In manyways this is the simplest of all methodsfor determining vertical dimension:The first step is to mount the patient’sexisting models with the seated condyle.The second step is to establish on themaxillary model the ideal maxillarycentral incisor incisal edge position,either in wax or composite. This positionis arrived at by evaluating the patient’smaxillary central incisor display withthe upper lip at rest and in a full smile.The third step is to determine if anyalteration to the lingual contour of themaxillary incisors is necessary, and ifso, to perform that alteration in waxor composite as well. Essentially, thedesired changes to the maxillary centralincisors have now been transferred tothe model.

The fourth step is to close the artic-ulator and evaluate the anterior andposterior occlusions. In some patientsthe desired changes to the maxillaryanterior teeth may be made without asignificant alteration to the anterior orposterior occlusion. However, in otherpatients the changes performed on themaxillary anterior will result in a pos-terior open bite when the articulator isclosed. The decision that must be madeis whether the posterior open bite willbe closed by building up the posteriorteeth and therefore opening the verticaldimension, or whether the posterioropen bite will be closed by altering themandibular incisors. In many patientseither approach may be successful.Generally, evaluating which teeth needrestoration guides the clinician as towhether the lower incisors should bemodified or the posterior teeth built up.Whenever possible, using the patient’sexisting vertical dimension makes iteasier for the patient to phase treatmentover time. The fifth step, if necessary,is to modify the mandibular incisors,shortening them until the posteriorteeth touch (if that was the ultimatedecision). In many cases of severe wear,lengthening them to avoid the need

Figure 16—The initial presentation of a 65-year-old man with severe anterior tooth wear desiringesthetic improvement.

Figure 17—On the left of the full-smile photograph, the white line illustrates the desired incisal posi-tion of the maxillary anterior teeth. On the right is a lip at rest, illustrating that the existing teeth are2.5 mm under the upper lip.

Figure 18—A view of the patient’s mounted models. There is severe wear and secondary eruption ofthe anterior teeth with minimal wear of the posterior teeth.

Figure 19—On the right, the desired alterations for the maxillary incisors have been made in wax.The mandibular incisors were reduced in length until the posterior teeth were in occlusion. The pho-tograph on the left shows how much the mandibular incisors would need to be shortened to allow forthe change in the maxillary anterior teeth with no change in vertical dimension.

Figure 20—On the left, the desired changes in the maxillary incisors have been made in wax. Themandibular incisors have been waxed to a normal length and the articulator has not yet been closeddown. On the right, the articulator is now closed until anterior contact occurs. At that point the deci-sion can be made as to whether the anterior relationship is acceptable or not. If it is deemed accept-able, then the incisors have created the new occlusal vertical dimension and the posterior teeth wouldnow be built into contact.


CE


for crown lengthening will now estab-lish the new vertical dimension to whichthe posterior teeth will be built. Thechosen vertical dimension should be acombination of the esthetics of the max-illary and mandibular incisor incisal edgeposition, the restorative needs of theanterior and posterior teeth, and thedesired functional needs of overbite andoverjet. It is arrived at on the articulatorthrough trial and error, while balancingall the previous factors as well as attempt-ing to do what is in the best interest ofthe patient. It is the adaptability ofpatients to alterations in vertical dimen-sion that allows us to take this approachto treatment rather than to believe thatonly one vertical dimension can beacceptable (Figures 16 through 22).

ConclusionThere are multiple acceptable ver-

tical dimensions at which patients canbe treated, therefore, using verticaldimension as a sole justification fortreatment is not supported. In addition,if the patient’s posterior teeth areunworn and in occlusion, virtually allpatients can be treated at their existingvertical dimension if they are willingto consider orthodontic movement oftheir anterior teeth or crown length-ening and restoration of their anteriorteeth. At the same time, if a patient

does need all of their dentition rehabil-itated, increasing vertical dimension isa perfectly acceptable way of achievingthe esthetics and functional results thatare desired.

References1. The Enigma of the Vertical Dimension.

Published in 2000 by the Center of HumanGrowth and Development, The Universityof Michigan.

2. Bjork A, Skieller V. Facial development andtooth eruption. Am J Orthod. 1972;62:339-383.

3. Bjork A. Skieller V. Normal and abnormalgrowth of the mandible: a synthesis of lon-gitudinal cephalometric implant studiesover a period of 25 years. Eur J Orthod.1983;5:1-46.

4. Sassouni V. A classification of skeletal facialtypes. Am J Orthod. 1969;55:109-123.

5. Beckmann SH, Kuitert RB, Prahl-AndersonB, et al. Alveolar and skeletal dimensionsassociated with overbite. Am J OrthodDentofacial Orthop. 1998;113:443-452.

6. Beckmann SH, Kuitert RB, Prahl-Anderson B,et al. Alveolar and skeletal dimensions asso-ciated with lower face height. Am J OrthodDentofacial Orthop. 1998;113:498-506.

7. Nanda SK. Growth patterns in subjects withlong and short faces. Am J Orthod Dento-facial Orthop. 1990;98:247-258.

8. Nanda SK. Patterns of vertical growth inthe face. Am J Orthod Dentofacial Orthop.1998;93:103-116.

9. Richardson A. Skeletal factors in anterioropen and deep bite. Am J Orthod. 1969;56:114-127

10. Brodie AG. On the growth pattern of thehuman head from the third month to theeighth year of life. Am J Anat. 1941;68:209-262.

11. Janson GR, Metaxas A, Woodside DG.Variation in maxillary and mandibular molarand incisor vertical dimension in 12-year-old subjects with excess normal and shorterlower anterior face height. Am J OrthodDentofacial Orthop. 1994;106:409-418.

12. Proffit WR, Field HW, Nixon WL, et al. Facialpattern differences in long-faced childrenand adults. Am J Orthod. 1984;85:217-223.

13. Proffit WR, Field HW, Nixon WL. Occlusalforces in normal and long-faced children. JDent Res. 1983;62:571-574.

14. Fish LC, Wolford LM, Epker B. Surgicalorthodontic correction of vertical maxillaryexcess. Am J Orthod. 1978;73:241-257.

15. Cangialosi T. Skeletal morphologic featuresof anterior open-bite. Am J Orthod. 1984;85:28-56.

16. Van Spronsen PH, Weijs WA, Valk J, et al. Acomparison of jaw muscle orientation andmoment arms of long-face and normaladults. J Dent Res. 1996;75:1372-1380.

17. Bell WH. Correction of the short-face syndrome/vertical maxillary deficiency; a preliminaryreport. J Oral Surg. 1997;35:110-120.

18. Opdebeec H, Bell WH. The short face syn-drome. Am J Orthod. 1987;73:499-511.

19. Linder-Anderson S, Woodside DG. Somecraniofacial variables related to small ordiminishing lower anterior face height.Swed Dent J. 1982;15(Suppl):131-146.

20. Wessberg GA, Fish LC, Epker BN. The short-face patient: Surgical-orthodontic treatmentoptions. J Clin Orthod. 1982;16:668-685.

21. Wessberg GA, Epker BN. Surgical inferiorrepositioning of the maxilla: treatment con-siderations and comprehensive manage-ment. Oral Surg Oral Med Oral Path. 1981;52:349-356.

22. Brodie AG. On the growth pattern of thehuman head from the third month to theeighth year of life. Am J Anat. 1941;68:209-262.

23. Ingervall B, Thilander B. Relation betweenfacial morphology and activity of the masti-catory muscles: An electromyographic andradiographic cephalometric investigation.J Oral Rehab. 1974;1:131-147.

24. Thompson IL, Kendrick GS. Changes in thevertical dimension of the human male skullduring third and fourth decades of life. AnatRec. 1964;150:209-214.

25. Tallgren A. Changes in adult face heightdue to aging, wear and loss of teeth andprosthetic treatment. Acta Odontol Scand.1957;15(Suppl 24):1-12.

26. Proffitt WK, Vig KW. Primary failure of erup-tion; a possible cause of posterior open-bite.Am J Orthod. 1981;80:173-190.

27. Gierie WV, Paterson RL, Proffit WR. Responseof eruption human premolars to force appli-cation. Arch Oral Biol. 1999;44:423-428.

28. Kahn J, Tallents RH, Katzberg RW, et al.Association between dental occlusal vari-able and intraarticular temporomandibularjoint disorders; horizontal and vertical over-lap. J Prosthet Dent. 1998;79:658-662.

29. Rivera-Morales WC, Mohl ND. Relationshipof occlusal vertical dimension to the healthof the masticatory system. J Prosth Dent.1991;65:547-553.

Figure 21—These before and after photographs appear to show a significant increase in verticaldimension; however, the maxillary anterior teeth have had 4 mm to 5 mm of periodontal crownlengthening. Although this patient’s entire mouth was reconstructed at once, the vertical dimensionwas increased only 1.5 mm because the patient already had excessive overjet.

Figure 22—Before and after photographs illustrate a significant change in appearance, primarilybecause of a significant change in tooth display with minimal alteration in vertical dimension.


30. Kovaleski WC, DeBoever J. Influence of occlusalsplints on jaw positions and musculature inpatients with temporomandibular joint dys-function. J Prosthet Dent. 1975;33:321-327.

31. Manns A, Miralles R, Santander H, ValdiviaJ. Influences of the vertical dimension inthe treatment of myofacial pain-dysfunc-tion syndrome. J Prosthet Dent. 1983;50:700-709.

32. Christensen J. Effect of occlusion-raisingprocedure on the chewing system. DenPract Dent Rec. 1970;20:233-238.

33. Carlsson GE, Ingervall B, Kocak G. Effect ofincreasing vertical dimension on the masti-catory system in subjects with natural teeth.J Prosth Dent. 1979;41:284-289.

34. Kohno S, Bando E. Functional adaptation ofmasticatory muscles as a result of largeincreases in the vertical dimension. DeschZahnarzt.

35. Rugh JD, Johnson RW. Vertical dimension dis-crepancies and masticatory pain/disfunction.In: Abnormal Jaw Mechanics. Solberg WKC,ed. Chicago: Quintessence. 1984:117-133.

36. Sions DG, Mense S. Understanding andmeasurement of muscle tone as related toclinical muscle pain. Pain. 1998;75:1-17.

37. Tryde G, Stoltze K, Morimoto T, Salk D.Long term changes in the perception ofcomfortable mandibular occlusal positions.J Oral Rehabil. 1977;4:9-15.

38. De Boever JA, Adriaens PA, Seynhaeve TM.Raising the vertical dimension of occlusionwith fixed bridges (abstract). J Dent Res.1989;68:902.

39. Hellsing G. Functional adaptation tochanges in vertical dimension. J ProsthetDent. 1984;52:867-870.

40. Maxwell LC, Carlson DS, McNamara JA,Faulkner JA. Adaptation of the masseter andtemporalis muscles following alteration inlength with or without surgical detach-ment. Anat Rec. 1981;200:127-137.

41. Wessberg GA, O’Ryan FS, Washburn MC,Epker BN. Neuromuscular adaptation tosurgical superior repositioning of the maxilla.J Maxillo Surg. 1981;9:117-122.

42. Hoppenreijs RJM, Freihofer HPM, StoelingaPJW, et al. Skeletal and dento-alveolar stabilityof Le Fort I: intrusion osteotomies and bimax-illary osteotomies in an anterior open bitedeformities: a retrospective tree-centre study.Int J Oral Maxillofac Surg. 1997;26:161-175.

43. Bailey LJ, Phillips C, Proffit WR, Turvey TA.Stability following superior repositioning ofthe maxilla by LeFort I osteotomy: five yearfollow-up. Int J Adult Orthod OrthodnathSurg. 1994;9:163-174.

44. Bell WH, Scheidman GB. Correction of verti-cal maxillary deficiency; stability and soft tis-sue changes. J Oral Surg. 1981;39:666-670.

45. Quejada JG, Bell WH, Kawamura H, ZhangX. Skeletal stability after inferior maxillaryrepositioning. Int J Adult Orthodon OrthognathSurg. 1987;2:67-74.

46. Ellis E III, Carlson DS, Frydenlund S. Stabilityand midface augmentation; an experimen-tal study of musculoskeletal interaction andfixation methods. J Oral Maxillofac Surg.1989;47:1062-1068.

47. Dahl BL, Krogstead O. Long term observa-tions of an increase occlusal face height

obtained by a combined orthodontic/prosthetic approach. J Oral Rehabil. 1985;12:173-176.

48. Ismail YH, George WA, Sassouni V, Scott RH.Cephalometric study of the changes occur-ring in the face height following prosthetictreatment. I. Gradual reduction of bothocclusal and rest face heights. J ProsthetDent. 1968;19:321-330.

49. Ismail YH, Sassoun I V. Cephalometric studyof the changes occurring in the face heightfollowing prosthetic treatment. II. Variabilityin the rate of face height reduction. J ProsthetDent. 1968;19:331-337.

50. Tallgren A. The continuing reduction of theresidual alveolar ridges in complete denturewearers: a mixed-longitudinal study covering25 years. J Prosthet Dent. 1972;27:120-132.

51. Forsberg CM, Eliasson S, Westergren H.Face height and tooth eruption in adults-a20-year follow-up investigation. Eur J Orthod.1991;13:249-254.

52. Dahl BL, Krogstad O. The effect of a partialbite raising splint on the occlusal face height:An x-ray cephalometric study in humanadults. Acta Odontol Scand. 1982; 40:17-24.

53. Manns A, Miralles R, Guerrero F. The changesin electrical activity of the postural musclesof the mandible upon varying the verticaldimension. J Prosthet Dent. 1981;45:438-445.

54. Michekatti A, Farella M, Vollaro S, MartinaR. Mandibular rest positions and electricalactivity of the masticatory muscles. J ProsthetDent. 1997;78:48-53.

55. Miles TS, Poliakov AV, Nordstrom MA.Responses of human masseter motor unitsto stretch. J Physiol. 1995;483:251-264.

56. Carr AB, Christensen LV, Donegan SJ, ZiebertGJ. Postural contractile activities of humanjaw muscles following use of an occlusalsplint. J Oral Rehabil. 1991;18:185-191.

57. Manns A, Miralles R, Palazzi C. EMG, biteforce, and elongation of the masseter mus-cle under isometric voluntary contractionsand variations of vertical dimension. JProsthet Dent. 1979;42:674-682.

58. Morimoto T, Abekura H, Tokeyama H,Hamada T. Alteration in the bite force andEMG activity with changes in the verticaldimension of edentulous subjects. J OralRehabil. 1996;23:336-341.

59. Lindauer SJ, Gay T, Rendell J. Effect of jawopening on masticatory muscle EMG-forcecharacteristics. J Dent Res. 1993;72:51-55.

60. Nakamura T, Inoue T, Ishigaki S, MaruyamaT. The effect of vertical dimension changeon mandibular movements and muscleactivity. Int J Prosthodont. 1988;1:297-301.

61. Hammond RJ, Beder OF. Increased verticaldimension and speech articulation errors. JProsthet Dent. 1984;52:401-406.

62. Howell PG. Incisal relationship during speech.J Prosthet Dent. 1986;56:93-99.

63. Howell PG. The variation in the size andshape of the human speech pattern withincisor tooth relation. Arch Oral Biol. 1987;32:587-592.

64. Stoller D. Mass examinations of the smallestvertical dimension during speech in 2000persons. Scweiz Mschr Zahnbeilk. 1969;79:735-751.

65. Benediktsson E. Variation in tongue and jawposition in “S” sound production in relationto front teeth occlusion. Acta Odontol Scand.1958;15:275-303.

66. Atwood DA. A critique of research of therest position of the mandible. J Prosth Dent.966;16:848-854.

67. Babu CL, Singh S, Rao SN. Determination ofvertical dimension of rest. A comparativestudy. J Prosthet Dent. 1987;58:238-245.

68. Garnick J, Ramfjord SP. Rest position-anelectromyographic and clinical investiga-tion. J Prosth Dent. 1962;12:895-911.

69. Feldman S. Rest vertical dimension deter-mined by electromyography with biofeed-back as compared to conventional methods.J Prosth Dent. 1978;84:216-219.

70. Atwood DA. A cephalometric study of therest position of the mandible. Part I. J ProsthDent. 1956;6:504-519.

71. Rugh JD, Drago CJ. Vertical dimension; Astudy of clinical rest position and jaw mus-cle activity. J Prosth Dent. 1981;45:670-675.

72. Thompson JR. The rest position of themandible and its application to analysis andcorrection of malocclusion. Angle Orthod.1949;19:162-187.

73. Thompson JR. The rest position of themandible and its significance to dental sci-ence. J Am Dent Assoc. 1946;33:151-180.

74. Fish F. The functional anatomy of the restposition of the mandible. Dent Pract DentRec. 1961;11:178-188.

75. Gross MD, Ormianer Z. A preliminary studyon the effect of occlusal vertical dimensionincrease on mandibular postural rest posi-tion. Dent Pract Dent Rec. 1961;11:178-188.

76. Ormianer Z, Gross M. A 2-year follow-up ofmandibular posture following an increase inocclusal vertical dimension beyond the clin-ical rest position with fixed restorations. JOral Rehabil. 1998;25:877-883.

77. Lund P, Nishiyama T, Moller E. Posturalactivity in the muscles of mastication withthe subject upright, inclined, and supine. Scand J Dent Res. 1970;78:417-424.

78. Lee RL. Esthetics and its relationship to func-tion. In: Fundamentals of Esthetics. RefenauctCR, ed. Quintessence.

79. Dumont TD. The Ideal Biologic Dental Model.OBI Foundation for Bioesthetic Dentistry.Rev. 2004.

80. Murphy T. Compensatory mechanisms infacial height adjustments to functional toothattrition. Aust Dent J. 1959;4:312-323.

81. Rifkin R. Facial analysis: A comprehensiveapproach to treatment planning in aesthet-ic dentistry. Pract Periodontics Aesthet Dent.2000;12:865-871.

82. McLaren EA, Rifkin R. Macroesthetics: facialand dentofacial analysis. J Calif Dent Assoc.2002;30:839-846.

83. Gross MD, Nissan J, Ormianer Z, et al. Theeffect of increasing occlusal vertical dimen-sion on face height. Int J Prosthodont. 2002;15:353-357.

1. Which of the following factors does not affectocclusal vertical dimension during growth anddevelopment?a. growth of the ramusb. gonial angle of the maxillac. gonial angle of the mandibled. eruption of the teeth

2. Treatment of vertical dimension in patientswith a long ramus often involves which of the following?a. double jaw surgeryb. single jaw surgeryc. orthodontic treatmentd. none of the above

3. Dentists commonly alter vertical dimension in order to:a. improve estheticsb. improve occlusal relationshipsc. gain space for the restoration of short or

worn teethd. all of the above

4. When vertical dimension is increased, restingmuscle activity level does which of the following?a. increases until there is approximately

10 mm to 12 mm of anterior vertical opening b. decreases until there is approximately

10 mm to 12 mm of anterior vertical openingc. decreases until there is approximately

7 mm to 9 mm of anterior vertical openingd. there is no change

5. Resting muscle activity level returns to levelsclose to pretreatment levels when verticalchange has been maintained for how long?a. 1 month to 2 monthsb. 3 to 4 monthsc. 6 to 8 monthsd. 10 to 12 months

6. Practitioners are sometimes concerned withhow a change in vertical dimension will affectthe patient’s speech, particularly sounds usingwhich letter?a. Lb. Pc. Sd. T

7. Problems with speech after a change in verticaldimension are often corrected after an adapta-tion period of how long?a. 1 weekb. 10 daysc. 2 to 4 weeksd. 6 to 8 weeks

8. Most dental schools advise how much of freeway space as normal?a. 1 mm to 2 mmb. 2 mm to 4 mmc. 4 mm to 6 mmd. 6 mm to 8 mm

9. Which of the following is not a method ofdetermining vertical dimension?a. use of freeway spaceb. use of trial appliancesc. TENSd. method of tooth proportion

10. In a study evaluating whether dentists werecapable of seeing the facial differences caused bychanges in vertical dimension, the differenceswere not seen until the change had reachedwhich of the following measurements? a. 2 mmb. 4 mmc. 6 mmd. 8 mm

Continuing Education QuizLoma Linda University School of Dentistry provides 1 hour of Continuing Education credit for this article for thosewho wish to document their continuing education efforts. To participate in this CE lesson, please log on towww.aegisce.net/aeid, where you may further review this lesson and test online for a fee of $14.00. To obtainmailing instructions or for more information, please call 877-4-AEGIS-1.


CE Approaches to Vertical Dimension - spearaesthetics.com · reduce the excessive tooth and...

Documents

Transcript of CE Approaches to Vertical Dimension - spearaesthetics.com · reduce the excessive tooth and...