consensus conference panel report: crown-height space guidelines for implant dentistry ... ·...

Consensus Conference Panel Report:Crown-Height Space Guidelines for

Implant Dentistry—Part 1Carl E. Misch, BS, DDS, MDS,*† Charles J. Goodacre, DDS, MSD,‡ Jon M. Finley, BA, DDS,§

Craig M. Misch, DDS, MDS,�¶ Mark Marinbach, CDT,# Tom Dabrowsky, LDT, RDT,** Charles E. English, DDS,††John C. Kois, DMD, MSD,‡‡ and Robert J. Cronin, Jr., BS, DDS, MSaa

Dental implants serve as a foun-dation for support of fixedand/or removable prostheses.

As such, preimplant prosthodonticconsiderations are a vital phase oftreatment before implant surgery. Forexample, the surgical decision to aug-ment or perform osteoplasty beforeimplant surgery will affect the crownheight of the prosthesis and, subse-quently, the desired prosthetic result.Therefore, the overall prosthetic treat-ment plan should be determined be-fore surgical intervention. Virtually allconventional forms of construction,from buildings to art form, require aclear vision of the end result before theproject is started.

Implant preprosthetic failure is inthe range of 0% to 20%, and is highlyrelated to bone volume and density.1

The highest risk of implant failure af-ter the prosthesis is fabricated is dur-ing the first 18 months. Implant loss,according to a limited literature review

from 1981 to 2001, may be related toprosthesis type and arch location.1

Fixed complete arch prostheses showan average failure rate of 10% in themaxilla and 3% in the mandible (range0% to 22%). Implant overdenturesshow a 19% failure rate in the maxillaand 4% in the mandible (range 0% to30%). Partially edentulous fixed par-tial dentures average an implant fail-ure rate of 6% in either the maxilla ormandible (range 1.9% to 12.5%). Be-cause more than 1 implant is used tosupport most restorations, the numberof prostheses affected in the post-prosthetic category of implant failuremay be 2 or 3 times the number ofimplant failures, but this is not welldocumented in the literature. Singlerestorations on implants show a meanaverage of 3% loss in either arch(range 0% to 11%).1 Therefore, thehighest complication rate for early im-plant failure after placement of im-plant restorations is for overdentures,followed by complete-arch fixed par-tial dentures, then fixed partial den-tures. Single restorations on implantshave the lowest implant failure inci-dence and appear to be the most pre-dictable restoration.

As a general rule, prostheses sup-ported by teeth have survival rates at2�5 years in the range of 97% andrarely are tooth abutments lost duringthis time.2 However, failure rates in-crease substantially over time with onequarter3 to one third4 of the prosthesesfailing after 15 years. Implant pros-thetic complications develop earlierin the process than natural tooth-supported restorations. For example,the early fracture rate of porcelain ap-proximates 6%, whereas tooth sup-ported restorations have a fracture rateof approximately 2% over the sametime.1 Loss of retention on naturaltooth restorations is rare within thefirst 4 years, whereas single tooth im-plants can have loose abutmentscrews. Screw loosening with singleimplants has occurred at a relativelyhigh rate initially (range 2% to 45%).With new screw designs and torquetightening protocols, the loosening hasbeen reduced to an average of 8%(range 0% to 12%) within the sametime.1 The primary causes of compli-cations with natural tooth-supportedrestorations relate to caries, loss ofretention, need for endodontic treat-ment, and porcelain fracture. How-

*Professor and Director of Oral Implantology, TempleUniversity, School of Dentistry, Philadelphia, PA.†CEO of Misch International Implant Institute, Beverly Hills, MI.‡Dean of the Loma Linda University School of Dentistry, LomaLinda, CA.§Private Practice, Prairie Village, KS.�Clinical Associate Professor at New York University,Department of Implant Dentistry, New York, NY.¶Private Practice, Sarasota, FL.#Assistant Professor Temple University, School of Dentistry,President of Nu-Life Long Island Dental Laboratories, WestHempstead, NY.**Owner of BIT Dental Laboratory Pueblo, CO.††Assistant Clinical Professor of Restorative Dentistry of theUniversity of Tennessee, Memphis, TN, and University ofOklahoma in Oklahoma City.‡‡Affiliate Professor in the Graduate Restorative Program atthe University of Washington. Private Practice Seattle, WA.aaDirector of the Postdoctoral Prosthodontics Program andProfessor at the University of Texas Health Science Center,San Antonio, TX.

ISSN 1056-6163/05/01404-312Implant DentistryVolume 14 • Number 4Copyright © 2005 by Lippincott Williams & Wilkins

DOI: 10.1097/01.id.0000188375.76066.23

The International Congress ofOral Implantologists sponsored aconsensus conference on the topic ofcrown height space on June 26 and27, 2004, in Las Vegas, Nevada. Thepanel communicated on several oc-casions before, during, and after themeeting, both as a group and amongindividuals. A consensus of 1 opin-

ion was not developed for most is-sues. However, general guidelinesemerged related to the topic. Thefollowing article is part 1 of a sum-mary of several guidelines that shouldbe of benefit to the profession at large.(Implant Dent 2005;14:312–321)Key Words: implant treatment plans,biomechanics, consensus reports

312 CROWN-HEIGHT SPACE GUIDELINES FOR IMPLANT DENTISTRY

ever, because implants do not decay orrequire endodontic therapy, once therestoration is functioning for morethan 2 years, the long-term survivalrate of the prosthesis is higher, ascompared to natural tooth restorations.After 10 years, reports of success rateshigher than 90% are not unusual withdental implants.

CROWN HEIGHT SPACE

The primary purpose of this con-sensus meeting was to provide guide-lines related to interarch space. Earlyin the discussions of the panel, it be-came apparent that the ideal dimen-sions of this space were difficult toascertain for either fixed or remov-able restorations. However, the con-sequences of too much or too littlecrown height space (CHS) in 1 archwas considered more relevant of aproblem, and guidelines for theseconditions were generally agreedupon.

The interarch distance is definedas the vertical distance between themaxillary and mandibular dentate oredentate arches under specific condi-tions (e.g., the mandible is at rest or inocclusion).5 A dimension of only 1arch does not have a defined term inprosthetics, therefore, Misch6 pro-posed the term “crown height space.”The CHS for implant dentistry is mea-sured from the crest of the bone to theplane of occlusion in the posterior re-gion and the incisal edge of the arch inquestion in the anterior region (Fig. 1).During restoration of an anterior re-gion of the mouth, the presence of avertical overbite means the CHS islarger in the maxilla than the spacefrom the crest of the ridge to the op-posing teeth incisal edge. In general,when the anterior teeth are in contactin centric occlusion, there is a verticaloverbite. Therefore, the anterior man-dibular CHS is usually measured fromthe crest of the ridge to the lingualcontacts of the maxillary anteriorteeth, which is also the incisal edge.However, the anterior maxillary CHSis measured from the maxillary crestalbone to the maxillary incisal edge, notthe occlusal contact position. The bio-mechanical aspects of CHS continueto the incisal edge because eccentric

movements of the mandible extend tothis position.

According to the consensus panel,the ideal CHS needed for a fixed im-plant prosthesis should range between8 and 12 mm. This measurement ac-counts for the biologic width, abut-ment height for cement retention orprosthesis screw fixation, occlusal ma-terial strength, esthetics, and hygieneconsiderations around the abutmentcrowns (Fig. 2). Removable prosthe-ses often require �12 mm CHS fordenture teeth and acrylic resin basestrength, attachments, bars, and oralhygiene considerations (Fig. 3).

BIOMECHANICS OF CHSMechanical complication rates for

implant prostheses are often the high-est of all complications reported in theliterature.7 Mechanical complicationsare often caused by excessive stress

applied to the implant-prosthetic sys-tem. Implant failure may occur fromoverload, and result in prosthesis fail-ure and bone loss around the failedimplants. Implant body fracture mayresult from fatigue loading of the im-plant at a higher force but occurs atless incidence than most complica-tions. The higher the force, the fewerthe number of cycles before fracture,so that the incidence increases. Crestalbone loss may also be related to ex-cessive forces and often occurs beforeimplant body fracture. The risk ofscrew loosening is increased whenforces are increased, and abutmentsand prosthetic screws have loosened atrates of 6% and 7%, respectively.1

Porcelain and/or occlusal materialfracture rates may increase as the forceto the restoration is increased. The riskof fracture to the opposing prosthesisincreases with an average of 12% in

Fig. 1. Crown height increases as the available bone resorbs in height. The CHS is measuredfrom the crest of the bone to the occlusal plane in the posterior and to the incisal edge of thearch in question in the anterior region.Fig. 2. The ideal CHS for a fixed restoration ranges from 8 to 12 mm. This dimension accountsfor the biologic width, abutment height for cement or screw retention, and occlusal material forstrength, esthetics, and hygiene considerations.Fig. 3. Removable implant overdentures often require �12 mm CHS for denture teeth, acrylicresin base, attachments, and bars for strength and oral hygiene considerations.Fig. 4. When the direction of load is in the long axis of the implant, the crown height does notincrease the force to the implant or bone.

IMPLANT DENTISTRY / VOLUME 14, NUMBER 4 2005 313

implant overdentures that oppose adenture.1 With resin veneer fixed par-tial dentures, 22% of the veneers frac-tured. Clips or attachment fractures inoverdentures may average 17%.1 Frac-ture of the framework and/or substruc-ture may also occur as a result of anincrease in biomechanical forces.

Force magnifiers are situations ordevices that increase the amount offorce applied, and include a screw,pulley, inclined plane, and a lever.7

The biomechanics of CHS are relatedto lever mechanics. The concepts of alever have been appreciated since thetime of Archimedes, 2000 years ago.The issues of cantilevers and implantswere shown with the edentulous man-dible, where the length of the posteriorcantilever directly related to complica-tions and/or failure of the prosthesis.Rather than a posterior cantilever, theCHS is a vertical cantilever, and,therefore, it is also a force magnifier.As a result, because CHS excess in-creases the amount of force, any of themechanical related complications as-sociated with implant prostheses mayalso increase.

When the direction of a force is inthe long axis of the implant, thestresses to the bone are not magnifiedin relation to the CHS (Fig. 4). How-ever, when the forces to the implantare on a cantilever or a lateral force isapplied to the crown, the forces aremagnified in direct relationship to thecrown height. Bidez and Misch8 eval-uated the effect of a cantilever on animplant and its relation to crownheight. When a cantilever is placedon an implant, there are 6 differentpotential rotation points (i.e., mo-ments) on the implant body. When thecrown height is increased from 10 to20 mm, 2 of 6 of these moments areincreased 200% (Figs. 5 and 6). Acantilevered force may be in any di-rection: facial, lingual, mesial, or dis-tal. Forces cantilevered to the facialand lingual are often called offsetloads. The bone width decrease is pri-marily from the facial aspect of theedentulous ridge. As a result, implantsare often placed more lingually thanthe center of the natural tooth root.This condition often results in a resto-ration cantilevered to the facial. Whenthe available bone height is also de-creased, the CHS is increased. There-

fore, not only is the potential length ofthe implant reduced in CHS condi-tions, the implant is positioned so thatan offset load is more likely to occur.

An angled load to a crown willalso magnify the force to the implant.A 12° force to the implant will in-crease the force by 20%. This increasein force is further magnified by thecrown height. For example, a 12° an-gle with a 100-N force will result witha 315-N mm force on a crown heightof 15 mm.9 Maxillary anterior teethare usually at an angle of �12° to theocclusal planes. Therefore, even im-plants placed in an ideal position areusually loaded at an angle. Maxillary

anterior crowns are often longer thanany other teeth in the arch, so theeffects of crown height cause a higherrisk of mechanical overload.

The angled force to the implantmay also occur when the patient goesinto protrusive or any lateral excursionbecause the incisal guide angle may be�20°. Therefore, anterior implantcrowns will be loaded at a consider-able angle during excursions, as com-pared to the long-axis position of theimplant. As a result, an increase in theforce to maxillary anterior implantsshould be compensated for, in the im-plant treatment plan. Most forces ap-plied to the osteointegrated implant

Fig. 5. When a cantilever is added to an implant, there are 6 different moments created.Fig. 6. When a cantilever is extended from an implant and the crown height is increased from10 to 20 mm, the lingual moment force and apical moment force are increased 200%.


body are concentrated in the crestal7�9 mm of bone, regardless of im-plant design and bone density.10 There-fore, implant body height is not aneffective method to counter the effectof crown height. In other words,crown-root ratio is a prosthetic con-cept, which may guide the restoringdentist when evaluating a natural toothabutment. However, the crown height-implant ratio is not a direct com-parison. Crown height is a verticalcantilever, which magnifies any lateralor cantilever force in either a tooth oran implant-supported restoration.However, this condition is not im-proved by increasing implant length.The higher the CHS, the higher thenumber of implants usually requiredfor the prosthesis, especially in thepresence of other force factors.7 Thisis a complete paradigm shift as com-pared to the concepts advocated orig-inally with many implants in more

available bone and small crownheights, and fewer implants withhigher crown heights in atrophiedbone (Figs. 7 and 8).

The CHS increases when crestalbone loss occurs around the implants.Therefore, an increased CHS may in-crease the forces to the crestal bonearound the implants and increase therisk of crestal bone loss. In turn, thiseffect may further increase the CHSand moment forces to the entire sup-port system, and increase screw loos-ening, crestal bone loss, implantfracture, and/or implant failure. Be-cause an increase in the biomechanicalforces is in direct relationship to theincrease in CHS, the treatment plan ofthe implant restoration should con-sider stress-reducing options when-ever the CHS is increased. Methods todecrease stress include:6

1. Shorten cantilever length.2. Less offset loads to the buccal or

lingual.3. Increase the number of implants.4. Increase the diameters of implants.5. Increase the surface area design of

implants.6. Make removable restorations less re-

tentive and use soft tissue support.7. Remove the removable restoration

during sleeping hours to reduce thenoxious effects of nocturnal para-function.

8. Splint implants together, whetherthey support a fixed or removableprosthesis.

A reduced CHS has biomechani-cal issues related to the strength ofimplant material and/or prostheticcomponents, flexibility of the mate-rial, and retention requirement of therestoration. The fatigue strength of amaterial is related to its diameter.8 Forexample, when a bar is one half asthick in dimension, it is 8 times moreflexible. In fixed restorations, themovement of the material mayincrease porcelain fracture, screwloosening, and/or uncemented restora-tions. Therefore, when reduced CHSexists, the material is much morelikely to have complications. CHS-related issues are accentuated by anexcessive CHS that places more forceson the implant/prosthetic system, andreduced CHS makes the prostheticcomponents weaker.

The retention and resistance formsof an abutment for a cemented pros-thesis are dramatically affected by theheight of the abutment.2 The arc ofdisplacement should be lower than theabutment height because the forcesabove the arc are in compression,while below the position of the arc, theforces are shear in nature. Materialssuch as cement, porcelain, and bonereact strongest to compression andweakest to shear components of force.

Existing Occlusal Vertical Dimension

To determine the interarch space,the overall issue of occlusal verticaldimension (OVD) must be addressed.Therefore, the issues of CHS must beconsidered after the development ofthis dimension. The patient’s existingOVD should be evaluated early inimplant prosthetic treatment plan be-cause any modification will signifi-cantly modify the overall treatment.Not only will a change in OVD requireat least 1 full arch to be reconstructed,it affects the CHS, and, therefore, thepotential number, size, position,and/or angulation requirements of theimplants. The OVD is defined as thedistance between 2 points (i.e., 1 inthe maxilla, and the other directly be-low in the mandible) when the occlud-ing members are in contact.5 Thisdimension requires clinical evaluationof the patient and cannot be evaluatedsolely on the diagnostic casts.

The determination of the OVD isnot a precise process because a rangeof OVD is possible without clinicalsymptoms.11 At one time, it was be-lieved that the dimension of occlusionwas very specific and remained stablethroughout a patient’s life. The OVDposition is not necessarily stable whenthe teeth are present or after the teethare lost. Long-term studies haveshown that this is not a constant di-mension and often is decreased overtime without clinical consequence, ineither the dentate, partially edentulous,or completely edentulous patient. Infact, a completely edentulous patientoften wears the same denture for morethan 10 years, during which time theOVD is reduced �10 mm, withoutsymptoms or patient awareness.

The OVD may be altered perma-nently without the symptoms of painand/or dysfunction. However, this is

Fig. 7. The original treatment plan for theBrånemark protocol used fewer implants inless available bone (with higher CHS) andmore implants in abundant available bone(with a smaller CHS).Fig. 8. The effect of the crown height sug-gests more implants should be inserted whenthe CHS is high and fewer implants insertedwhen the CHS is more ideal.


not to say altering the OVD has noconsequence. A change in OVD af-fects the interarch distance betweenthe arches. As such, it may affect thecrown-to-root (implant) ratio andamount of biomechanical forces ap-plied to the support system of a pros-thesis. In addition, any change in theOVD will also modify the horizontaldimensional relationship of the max-illa to the mandible. As a result, theOVD difference will change the ante-rior guidance, and the range of func-tion and esthetics.

The most important effect ofOVD on tooth (implant) loading maybe the impact on the biomechanics ofanterior guidance.12 The more closedthe OVD, the steeper the anteriorguidance and the higher the verticaloverlap of the anterior teeth. Theseconditions will increase the forces tothe anterior teeth and decrease the riskof posterior interferences during ec-centric mandibular movements orfunction. Opening the OVD has theopposite effects. In general, for thedentate patient, it is more risky toclose an OVD than to open this dimen-sion because the mandibular anteriorteeth may be positioned more facial, ina closer relationship to the maxillaryteeth in centric occlusion. However, incompletely edentulous patients re-stored with fixed implant prostho-dontics, a change in OVD in eitherdirection may have biomechanicalconsequences. Opening the OVD anddecreasing the incisal guidance result-ing in a bilateral balanced occlusionmay increase forces to posterior im-plants in any mandibular excursion.Closing the OVD may increase theforces to anterior implants during anyexcursion. On occasion, a change inthe OVD may also affect the sibilantsounds of an individual because it alsochanges the horizontal position of themandible.

The OVD is almost never natu-rally too large, and, unless some man-made interference has been created, itis within clinical guidelines or de-creased. Therefore, the restoring den-tist most often should determine if theOVD needs to be increased. In otherwords, the existing OVD is a place tostart the evaluation, not a position thatnecessarily must be maintained. Thisis not a casual decision because in-

creasing the OVD will often requirerestoration of all segments of themouth, with the exception of the max-illary anterior teeth, if acceptable.

According to Kois and Phillips,11

there are primarily 3 times that a re-storing dentist should consider a mod-ification of the OVD: (1) esthetics, (2)function, and (3) structural needs ofthe dentition. Esthetics is related toOVD for incisal edge positions, facialmeasurements, and the occlusal plane.Function is related to the canine posi-tions, the incisal guidance, and angleof load to teeth and/or implants. Struc-tural requirements are related to di-mensions of teeth for restoration,while maintaining a biologic width.

Methods to Evaluate OVD

All the techniques used in tradi-tional prosthodontics are also used toevaluate and/or establish the OVD.These techniques most often includethe objective method of measuring fa-cial dimensions, and/or the subjectivemethods of esthetics, resting arch po-sition, and speaking space. There is noconsensus on the ideal method to ob-tain the OVD. Therefore, this dimen-sion is part art form and part science.Yet, it is critical enough that a finaltreatment plan should not be rendereduntil a determination has been maderelative to this dimension.

The maxillary anterior horizontaland vertical tooth position is evaluatedbefore any other segment of thearches, including the OVD. If themaxillary anterior teeth are signifi-cantly malpositioned, the clinicianshould obtain further diagnostic stud-ies, such as a cephalometric radio-graph, to determine the relationship ofthe maxilla to the cranial base. Thepatient may have unfavorable skeletalrelationships, including vertical max-illary excess or deficiency. If thepositions of the natural maxillary an-terior teeth are undesirable for anyreason, orthodontics, orthognathicsurgery, and/or restoration may beindicated. Once the position of themaxillary anterior teeth is acceptable,the next prosthetic guidelines requirethe determination of the OVD.

The subjective methods to deter-mine OVD include the use of restinginterocclusal distance and speech-based techniques using sibilant

sounds. Niswonger13 proposed the useof the interocclusal distance (freewayspace), which assumes that the patientrelaxes the mandible into the sameconstant physiologic rest position. Thepractitioner then subtracts 3 mm fromthe measurement to determine theOVD. There are 2 aspects that conflictwith this method as a primary factor.First, the amount of freeway space ishighly variable in the same patient,depending on several factors, includ-ing head posture, emotional state,presence or absence of teeth, para-function, and time of recording(higher in the morning). Second, in-terocclusal distance at rest varies3�10 mm from one patient to another.As a result, the distance to subtractfrom the freeway space is unknownfor a specific patient. Therefore, thephysiologic rest position should not bethe primary method to evaluate OVD.

Silverman14 stated that approxi-mately 1 mm should exist between theteeth when the “S” sound is made.Pound15 further developed this con-cept for the establishment of centricand vertical jaw relationship recordsfor complete dentures. Although thisconcept is acceptable, it does not cor-relate to the original OVD of the pa-tient. Patients with dentures oftenwear the same prosthesis for morethan 14 years, and during this time,lose �10 mm of their original OVD.Yet, all these patients are able to say“Mississippi” with their existing pros-thesis. If speech was related to theoriginal OVD, these patients wouldnot be able to pronounce the “S”sounds because their teeth would bemore than 12 mm apart. Therefore,speaking space should not be used as aprimary method to evaluate OVD.

Kois and Phillips11 have noted thatthe subjective “esthetic” method to es-tablish an OVD is the most difficult toteach inexperienced dental students sothat it is least likely to be initiallyaddressed when teaching the conceptsof determining OVD. However, expe-rienced clinicians often consider thismethod to be a primary factor relatedto OVD. Once the position of the max-illary incisor edge is determined, theOVD influences esthetics of the facein general.

Facial dimensions are directly re-lated to the ideal facial esthetics of an


individual and are able to be evaluatedregardless of the degree of experienceof the clinician. Because facial dimen-sions are an objective evaluation,which is related to esthetics, it is usu-ally the method of choice to evaluateinitially the existing OVD and/or es-tablish a different OVD during pros-thetic reconstruction. The OVD basedupon facial measurements may be per-formed without the additional assis-tance of radiography or other tests.Facial measurements can be tracedback to antiquity, in which sculptorsand mathematicians followed the“Golden Proportion,” later specifiedas a ratio of 1.618–1. Later on, Leo-

nardo da Vinci16 contributed severalobservations and drawings on facialproportions, which he called “DivineProportions.” He observed that thedistance between the chin and bottomof the nose was a similar dimensionas: (1) the hairline to the eyebrows, (2)the height of the ear, and (3) the eye-brows to the bottom of the nose (Fig.9). Each of these dimensions equaledone third of the face. Many profes-sionals, including plastic surgeons,oral surgeons, artists, orthodontists,and morticians, use facial measure-ments to determine OVD.17,18 A re-view of the literature by Misch19 foundmany different sources that revealmany correlations of features that cor-respond to the OVD, including:

1. The horizontal distance betweenthe pupils.

2. The horizontal distance from theouter canthus of 1 eye to the innercanthus of the other eye.

3. Twice the horizontal length of 1eye.

4. Twice the horizontal distancefrom the inner canthus of 1 eye tothe inner canthus of the other eye.

5. The horizontal distance from theouter canthus of the eye to the ear.

6. The horizontal distance from 1corner of the lip to the other, fol-lowing the curvature of the mouth(cheilion to cheilion).

7. The vertical distance from the ex-ternal corner of the eye (outercanthus) to the corner of themouth.

8. The vertical height of the eyebrowto the ala of the nose.

9. The vertical length of the nose atthe midline (from the nasal spine{subnasion} to the glabella point.

10. The vertical distance from thehairline to the eyebrow line.

11. The vertical height of the ear.12. The distance between the tip of

the thumb and tip of the indexfinger when the hand lies flat, fin-gers next to each other (Fig. 10).

All these measurements do not ex-actly correspond to each other but usu-ally do not vary by more than a fewmillimeters, with the exception of thevertical height of the ear, when theface has dimensional balance. By av-eraging several of these measure-ments, the existing OVD may be

compared to give a clinical impressionof the accuracy with this objective ap-proach. The subjective criteria of es-thetics may then be considered afterthe facial dimensions are in balancewith each other.

Radiographic methods to deter-mine an objective OVD are alsowidely published in the literature. Acephalometric radiograph and tracingare suggested when gross jaw excessor deficiency is noted. These condi-tions may be caused from verticalmaxillary excess, vertical maxillarydeficiency, vertical mandibular excess(long chin), vertical mandibular defi-ciency (short chin), apertognathia,and/or class II division II (deep bite)situations. Orthodontic treatment plan-ning of a dentate patient often includesa lateral cephalogram and may be usedto evaluate OVD (glabella-subnasale,subnasale-menton). The same mea-surements may be performed on theedentulous patient (Fig. 11).

Esthetics are influenced by OVDbecause of its relationship to the max-illomandibular positions. The smallerthe OVD, the more class III the man-dibular jaw relationship becomes, andthe higher the OVD, the more class IIthe mandible becomes. The maxillaryanterior tooth position is first deter-mined and is most important for theesthetic criteria of the reconstruction.Alteration of the OVD for estheticsrarely includes the maxillary tooth po-sition. For example, the OVD positionmay be influenced by the need tomake the mandible less harsh lookingfor a patient with a large chin button(mental protuberance). Once the OVDsatisfies the esthetic requirement ofthe prosthetic reconstruction, it maystill be slightly modified. For example,the OVD may be modified to improvethe direction of force on the anteriorimplants. In addition, anterior mandib-ular implants on occasion are too fa-cial to the incisal edge position, andincreasing the OVD makes them mucheasier to restore. Therefore, becausethe OVD is not an exact measurement,the ability to alter this dimension,within limits, may often be beneficial.

CONCLUSION

Implant prostheses have a higherrate of mechanical complications than

Fig. 9. A drawing by Leonardo De Vinci16 sug-gests the face has common measurementsthat are similar to the distance from the bot-tom of the nose to the bottom of the chin.Fig. 10. A review of the literature by Misch19

found 11 measurements that were similar tothe OVD dimension.Fig. 11. A lateral cephalogram may be usedto help evaluate the OVD in a dentate oredentulous patient.


failure of an implant. A number offactors may increase the mechanicalload to an implant restoration, includ-ing an increased CHS. The CHS actsas a vertical cantilever to any angledor offset load to the restoration. As aresult, excessive CHS should havestress reducing protocols, includingshorter cantilever length, less offsetloads, increased implant number, in-creased implant diameter, increasedsurface area for implant designs, re-movable verses fixed restoration,which are removed during sleep, andsplinting implants together. A reducedCHS also has mechanical conse-quences to the restoration, includingreduced retention of the abutmentsand an increased risk related to thebending fracture resistance of theprosthesis.

The CHS is affected by the OVD.Determination of the OVD is not aprecise process, and a clinical range ispossible without clinical symptoms.The existing OVD of a patient is rarelynaturally too large. A decrease inOVD is more common in the completeedentulous patient. A modification ofthe OVD may be made by the dentistfor esthetics, function, and/or struc-tural needs of the dentition. The OVDmay be determined by objective orsubjective methods.

These guidelines will appear asPart 2 in the next issue of ImplantDentistry.

Disclosure

The authors claim to have no finan-cial interest in any company or any ofthe products mentioned in this article.

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14. Silverman MM. Accurate measure-ment of vertical dimension by phoneticsand the speaking centric space. Part I.Dent Dig. 1951;57:261-265.

15. Pound E. Let/s/be your guide.J Prosthet Dent. 1977;38:482-489.

16. Leonardo da Vinci 1452–1519, An-atomical Studies. The anatomy of manfrom Queen Elizabeth II private collection;Windsor Castle, UK, circa 1488.

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Reprint requests and correspondence to:Carl E. Misch, BS, DDS, MDSSuite 25016231 Fourteen Mile RoadBeverly Hills, MI 48025Phone: (248) 642-3199Fax: (248) 642-3794E-mail: [email protected]


Abstract Translations [German, Spanish, Portugese, Japanese]

AUTOR(EN): Carl E Misch, BS, DDS,MDS*, Charles J. Goddaere, DDS, MSD**,Jon M. Finley, BA, DDS***, Craig M. Misch,DDS, MDS#, Mark Marinbach, CDT##, TomDabrowski, LDT, RDT###, Charles E. En-glish, DDS�, John C. Kois, DMD, MSD��,sowie Robert J. Cronin Jr., BS, DDS,MS��. *Professor und Direktor der oralenImplantologie, Temple Universitat, zahn-medizinische Fakultat, Philadelphia, PA, USA,CEO des Misch Internationalen Implan-tierungsinstituts, Beverly Hills, MI, USA.**Dekan der zahnmedizinischen Fakultat derLoma Linda Universitat, Loma Linda, CA,USA.***Privat praktizierender Arzt, PrairieVillage, KS, USA. #Klinischer A.O. Professoran der New Yorker Universitat, Abteilung furImplantatgestutzte Zahnheilkunde, New York,NY, USA; privat praktizierender Arzt, Sara-sota, FL, USA. ##Assistenzprofessor der Tem-ple Universitat, zahnmedizinische Fakultat,Prasident der Nu-Life Long Island Zahnlabo-ratorien, West Hempstead, NY 15522. ###In-haber des BIT zahntechnischen LaborsPueblo, CO, USA. �Klinischer Assistenzpro-fessor der wiederherstellenden Zahnheilkundeder Universitat von Tennessee, Memphis, TN,USA und der Universitat von Oklahoma inOklahoma City. ��Professor im Verbund desGraduiertenprogramms zur Wiederherstel-lungsforschung an der Universitat von Wash-ington, private praktizierender Arzt, Seattle,WA, USA. ��Leiter des Programms furZahnersatzkunde fur Doktoranden und Profes-sor an der Universitat des Zentrums fur Ge-sundheitsforschung in Texas, San Antonio, TX,USA. Schriftverkehr: Carl E. Misch, DDS,16231 Fourteen Mile Road, Suite 250, BeverlyHills, MI 48025. Telefon: 248-642-3199, Fax:248-642-3794

Bericht der Podiumsdiskussion innerhalb der Konferenz zur Erzielung eines Konsensin Bezug auf die Richtlinien der Abstandshohenbildung bei Uberkronungen fur dieImplantierungszahnheilkunde: Teil 1

ZUSAMMENFASSUNG: Der internationale Kongress der Oralimplantologen (Interna-tional Congress of Oral Implantologists–ICOI) initiierte im Zeitraum vom 26. bis 27. Juni2004 in Las Vegas eine Konferenz zur Erzielung eines Konsens uber die Abstandsho-henbildung bei Uberkronungen. Das Gremium erhielt Gelegenheit, sich bereits im Vorfeldder Konferenz verschiedentlich sowie wahrend und nach der Besprechung als Gruppe undunter den einzelnen Teilnehmern auszutauschen. Fur die meisten Themenbereiche konntekeine ubereinstimmende Ansicht erzielt werden. Allerdings gelang es, allgemeine Rich-tlinien in Bezug auf diesen Themenkomplex aufzustellen. Das nachfolgende Dokumentstellt Teil 1 einer Zusammenfassung verschiedener dieser Richtlinien dar, die fur dieGesamtheit der Zahnheilkundigen von Vorteil sein konnen.

AUTOR(ES): Carl E. Misch, BS, DDS,MDS*, Charles J. Goodacre, DDS, MSD**,Jon M. Finley, BA, DDS***, Craig M. Misch,DDS, MDS#, Mark Marinbach, CDT##, TomDabrowsky, LDT, RDT###, Charles E. En-glish, DDS�, John C. Kois, DMD, MSD��,y Robert J. Cronin, Jr., BS, DDS, MS��.*Profesor y Director de Implantologıa Oral,Temple University, Facultad de Odontologıa,Filadelfia, PA, EE.UU., Jefe Ejecutivo delMisch International Implant Institute, BeverlyHills, MI, EE.UU. **Decano de la Facultadde Odontologıa de Loma Linda University,Loma Linda, CA EE.UU. ***Practica Pri-vada, Prairie Village, KS, EE.UU. #ProfesorClınico Asociado de New York University, De-partamento de Odontologıa de Implantes,Nueva York, NY, EE.UU., Practica Privada,Sarasota, FL, EE.UU. ##Profesor Asistente,

4 Informe del panel de una conferencia de consenso: Pautas para el espacio de la alturade la corona para la odontologıa de implantes: parte I

ABSTRACTO: El Congreso International de Implantologos Orales (ICOI por sus siglas eningles) patrocino una conferencia de consenso sobre el tema espacio de la altura de lacorona entre el 26 y el 27 de junio del 2004 en Las Vegas, Nevada. El panel se comunicoen varias ocasiones antes, durante y despues de la reunion, como grupo y como individuos.El consenso de una sola opinion no se logro en la mayorıa de las cuestiones. Sin embargo,surgieron pautas generales relacionadas con el tema. El siguiente trabajo es la Parte I deun resumen de varias de las pautas que deberıan ser de utilidad para la profesion engeneral.


Temple University, Facultad de Odontologıa,Presidente de Nu-Life Long Island DentalLaboratories, West Hempstead, NY 15522.###Dueno de BIT Dental Laboratory, Pueblo,CO, EE.UU. �Profesor Asistente Clınico deOdontologıa de Restauracion de la Univer-sidad de Tennessee, Memphis, TN y Universityof Oklahoma en Oklahoma City. ��ProfesorAfiliado en el Programa de Restauracion paraGraduados de la Universidad de Washington.Practica Privada, Seattle, WA, EE.UU.��Director del Programa de Prostodon-tica Postdoctoral y Profesor del Centro deCiencias de la Salud de la Universidad deTexas, San Antonio, TX, EE.UU. Correspon-dencia a: Carl E. Misch, DDS, 16231 Four-teen Mile Road, Suite 250, Beverly Hills, MI48025. Telefono: 248-642-3199, Fax: 248-642-3794.

AUTOR(ES): Carl E. Misch, Bacharel emCiencia, Cirurgiao-Dentista, Medico*, CharlesJ. Goodacre, Cirurgiao-Dentista, Medico**,Jon M. Finley, Bacharel em Letras, Cirurgiao-Dentista***, Craig M. Misch, Cirurgiao-Dentista, Medico#, Mark Marinbach, TecnicoDentario##, Tom Dabrowsky, Tecnico Den-tario###, Charles E. English, Cirurgiao-Dentista�, John C. Kois, Medico, Mestre emCiencia�� e Robert J. Cronin, Jr. Bacharelem Ciencia, Cirurgiao-Dentista, Mestre emCiencia��. *Professor e Diretor de Im-plantologia Oral, Temple University, Facul-dade de Odontologia, Filadelfia, PA, EUA,CEO do Misch International Implant Institute,Beverly Hills, MI, EUA. **Decano da Facul-dade de Odontologia da Loma Linda Univer-sity, Loma Linda, CA, EUA. ***ClınicaParticular, Prairie Village, KS, EUA. #Profes-sor Clınico Associado na Universidade deNova York, Departamento de Odontologia deImplante, Nova York, NY, EUA, Clınica Par-ticular, Sarasota, FL, EUA. ##Professor As-sistente da Temple University, Faculdade deOdontologia, Presidente dos LaboratoriosDentarios Nu-Life, de Long Island, WestHempstead, NY 15522. ###Proprietario doLaboratorio Dentario BIT, Pueblo, CO, EUA.�Professor Assistente Clınico de OdontologiaRestauradora da Universidade do Tennessee,Memphis, TN, EUA e Universidade de Okla-homa em Oklahoma City. ��Professor Afili-ado no Programa Graduado Restaurador naUniversidade de Washington, Clınica Partic-ular, Seattle, WA, EUA. ��Diretor doPrograma de Prostodontica em Nıvel de Pos-Doutorado e Professor do Centro de Cienciasda Saude da Universidade do Texas, San An-tonio, TX, EUA. Correspondencia para: CarlE. Misch, Cirurgiao-Dentista, 16231 FourteenMile Road, Suite 250, Beverly Hills, MI 48025.Telefone: 248-642-3199, Fax: 248-642-3794.

Relatorio do Painel da Conferencia de Consenso: Diretrizes de Espaco de Altura daCoroa para Odontologia de Implante: Parte I

RESUMO: O Congresso Internacional de Implantologista Oral (ICOI) patrocinou umaconferencia de consenso sobre o topico de Espaco de Altura da Coroa em 26-27 de junhode 2004, em Las Vegas, Nevada. O painel comunicou em varias ocasioes antes, durantee apos da reuniao, tanto como grupo quanto entre indivıduos. Um consenso de umaopiniao nao foi desenvolvido para a maioria das questoes. Contudo, diretrizes geraisemergiram, relacionadas ao topico. O seguinte artigo e a Parte I de um resumo de variasdas diretrizes que deveriam ser de benefıcio para a profissao em geral.


consensus conference panel report: crown-height space guidelines for implant dentistry ... ·...

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