Consensus Conference Panel Report: -Height Space Guidelines for Implant —Part 1

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

ental implants serve as a foun- The International Congress of ion was not developed for most is- dation for support of fixed Oral Implantologists sponsored a sues. However, general guidelines D and/or removable prostheses. consensus conference on the topic of emerged related to the topic. The As such, preimplant prosthodontic crown height space on June 26 and following article is part 1 of a sum- considerations are a vital phase of 27, 2004, in Las Vegas, Nevada. The mary of several guidelines that should treatment before implant surgery. For panel communicated on several oc- be of benefit to the profession at large. example, the surgical decision to aug- ment or perform osteoplasty before casions before, during, and after the (Implant Dent 2005;14:312–321) implant surgery will affect the crown meeting, both as a group and among Key Words: implant treatment plans, height of the prosthesis and, subse- individuals. A consensus of 1 opin- biomechanics, consensus reports quently, the desired prosthetic result. Therefore, the overall prosthetic treat- from 1981 to 2001, may be related to As a general rule, prostheses sup- ment plan should be determined be- prosthesis type and arch location.1 ported by teeth have survival rates at fore surgical intervention. Virtually all Fixed complete arch prostheses show 2Ϫ5 years in the range of 97% and conventional forms of construction, an average failure rate of 10% in the rarely are tooth abutments lost during from buildings to art form, require a maxilla and 3% in the mandible (range this time.2 However, failure rates in- clear vision of the end result before the 0% to 22%). Implant overdentures crease substantially over time with one project is started. show a 19% failure rate in the maxilla quarter3 to one third4 of the prostheses Implant preprosthetic failure is in and 4% in the mandible (range 0% to failing after 15 years. Implant pros- the range of 0% to 20%, and is highly 1 30%). Partially edentulous fixed par- thetic complications develop earlier related to bone volume and density. tial average an implant fail- in the process than natural tooth- The highest risk of implant failure af- ure rate of 6% in either the maxilla or supported restorations. For example, ter the prosthesis is fabricated is dur- mandible (range 1.9% to 12.5%). Be- the early fracture rate of porcelain ap- ing the first 18 months. Implant loss, cause more than 1 implant is used to proximates 6%, whereas tooth sup- according to a limited literature review support most restorations, the number ported restorations have a fracture rate of prostheses affected in the post- of approximately 2% over the same prosthetic category of implant failure time.1 Loss of retention on natural *Professor and Director of Oral Implantology, Temple University, School of Dentistry, Philadelphia, PA. may be 2 or 3 times the number of tooth restorations is rare within the †CEO of Misch International Implant Institute, Beverly Hills, MI. ‡Dean of the Loma Linda University School of Dentistry, Loma implant failures, but this is not well first 4 years, whereas single tooth im- Linda, CA. §Private Practice, Prairie Village, KS. documented in the literature. Single plants can have loose abutment ʈClinical Associate Professor at New York University, Department of Implant Dentistry, New York, NY. restorations on implants show a mean screws. Screw loosening with single ¶Private Practice, Sarasota, FL. #Assistant Professor Temple University, School of Dentistry, average of 3% loss in either arch implants has occurred at a relatively President of Nu-Life Long Island Dental Laboratories, West 1 Hempstead, NY. (range 0% to 11%). Therefore, the high rate initially (range 2% to 45%). **Owner of BIT Dental Laboratory Pueblo, CO. ††Assistant Clinical Professor of Restorative Dentistry of the highest complication rate for early im- With new screw designs and torque University of Tennessee, Memphis, TN, and University of plant failure after placement of im- tightening protocols, the loosening has Oklahoma in Oklahoma City. ‡‡Affiliate Professor in the Graduate Restorative Program at plant restorations is for overdentures, been reduced to an average of 8% the University of Washington. Private Practice Seattle, WA. aaDirector of the Postdoctoral Program and followed by complete-arch fixed par- (range 0% to 12%) within the same Professor at the University of Texas Health Science Center, 1 San Antonio, TX. tial dentures, then fixed partial den- time. The primary causes of compli- tures. Single restorations on implants cations with natural tooth-supported ISSN 1056-6163/05/01404-312 Implant Dentistry have the lowest implant failure inci- restorations relate to caries, loss of Volume 14 • Number 4 Copyright © 2005 by Lippincott Williams & Wilkins dence and appear to be the most pre- retention, need for endodontic treat- DOI: 10.1097/01.id.0000188375.76066.23 dictable restoration. ment, and porcelain fracture. How-

312 CROWN-HEIGHT SPACE GUIDELINES FOR IMPLANT DENTISTRY ever, because implants do not decay or require endodontic therapy, once the restoration is functioning for more than 2 years, the long-term survival rate of the prosthesis is higher, as compared to natural tooth restorations. After 10 years, reports of success rates higher than 90% are not unusual with dental implants.

CROWN HEIGHT SPACE The primary purpose of this con- sensus meeting was to provide guide- lines related to interarch space. Early in the discussions of the panel, it be- came apparent that the ideal dimen- sions of this space were difficult to ascertain for either fixed or remov- able restorations. However, the con- sequences of too much or too little crown height space (CHS) in 1 arch was considered more relevant of a problem, and guidelines for these conditions were generally agreed upon. Fig. 1. Crown height increases as the available bone resorbs in height. The CHS is measured The interarch distance is defined from the crest of the bone to the occlusal plane in the posterior and to the incisal edge of the as the vertical distance between the arch in question in the anterior region. maxillary and mandibular dentate or Fig. 2. The ideal CHS for a fixed restoration ranges from 8 to 12 mm. This dimension accounts edentate arches under specific condi- for the biologic width, abutment height for cement or screw retention, and occlusal material for strength, esthetics, and hygiene considerations. tions (e.g., the mandible is at rest or in Ն 5 Fig. 3. Removable implant overdentures often require 12 mm CHS for denture teeth, acrylic ). A dimension of only 1 resin base, attachments, and bars for strength and oral hygiene considerations. arch does not have a defined term in Fig. 4. When the direction of load is in the long axis of the implant, the crown height does not prosthetics, therefore, Misch6 pro- increase the force to the implant or bone. posed the term “crown height space.” The CHS for implant dentistry is mea- sured from the crest of the bone to the movements of the mandible extend to applied to the implant-prosthetic sys- plane of occlusion in the posterior re- this position. tem. Implant failure may occur from gion and the incisal edge of the arch in According to the consensus panel, overload, and result in prosthesis fail- question in the anterior region (Fig. 1). the ideal CHS needed for a fixed im- ure and bone loss around the failed During restoration of an anterior re- plant prosthesis should range between implants. Implant body fracture may gion of the mouth, the presence of a 8 and 12 mm. This measurement ac- result from fatigue loading of the im- vertical overbite means the CHS is counts for the biologic width, abut- plant at a higher force but occurs at larger in the maxilla than the space ment height for cement retention or less incidence than most complica- from the crest of the ridge to the op- prosthesis screw fixation, occlusal ma- tions. The higher the force, the fewer posing teeth incisal edge. In general, terial strength, esthetics, and hygiene the number of cycles before fracture, when the anterior teeth are in contact considerations around the abutment so that the incidence increases. Crestal in centric occlusion, there is a vertical crowns (Fig. 2). Removable prosthe- bone loss may also be related to ex- overbite. Therefore, the anterior man- ses often require Ն12 mm CHS for cessive forces and often occurs before dibular CHS is usually measured from denture teeth and acrylic resin base implant body fracture. The risk of the crest of the ridge to the lingual strength, attachments, bars, and oral screw loosening is increased when contacts of the maxillary anterior hygiene considerations (Fig. 3). forces are increased, and abutments teeth, which is also the incisal edge. and prosthetic screws have loosened at However, the anterior maxillary CHS BIOMECHANICS OF CHS rates of 6% and 7%, respectively.1 is measured from the maxillary crestal Mechanical complication rates for Porcelain and/or occlusal material bone to the maxillary incisal edge, not implant prostheses are often the high- fracture rates may increase as the force the occlusal contact position. The bio- est of all complications reported in the to the restoration is increased. The risk mechanical aspects of CHS continue literature.7 Mechanical complications of fracture to the opposing prosthesis to the incisal edge because eccentric are often caused by excessive stress increases with an average of 12% in

IMPLANT DENTISTRY /VOLUME 14, NUMBER 4 2005 313 implant overdentures that oppose a denture.1 With resin fixed par- tial dentures, 22% of the veneers frac- tured. Clips or attachment fractures in overdentures may average 17%.1 Frac- ture of the framework and/or substruc- ture may also occur as a result of an increase in biomechanical forces. Force magnifiers are situations or devices that increase the amount of force applied, and include a screw, pulley, inclined plane, and a lever.7 The biomechanics of CHS are related to lever mechanics. The concepts of a lever have been appreciated since the time of Archimedes, 2000 years ago. The issues of cantilevers and implants were shown with the edentulous man- dible, where the length of the posterior cantilever directly related to complica- tions and/or failure of the prosthesis. Rather than a posterior cantilever, the CHS 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 the mechanical related complications as- sociated with implant prostheses may also increase. When the direction of a force is in the long axis of the implant, the stresses to the bone are not magnified in relation to the CHS (Fig. 4). How- ever, when the forces to the implant are on a cantilever or a lateral force is applied to the crown, the forces are magnified in direct relationship to the crown height. Bidez and Misch8 eval- uated the effect of a cantilever on an 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 from implant and its relation to crown 10 to 20 mm, the lingual moment force and apical moment force are increased 200%. height. When a cantilever is placed on an implant, there are 6 different potential rotation points (i.e., mo- ments) on the implant body. When the fore, not only is the potential length of anterior crowns are often longer than crown height is increased from 10 to the implant reduced in CHS condi- any other teeth in the arch, so the 20 mm, 2 of 6 of these moments are tions, the implant is positioned so that effects of crown height cause a higher increased 200% (Figs. 5 and 6). A an offset load is more likely to occur. risk of mechanical overload. cantilevered force may be in any di- An angled load to a crown will The angled force to the implant rection: facial, lingual, mesial, or dis- also magnify the force to the implant. may also occur when the patient goes tal. Forces cantilevered to the facial A 12° force to the implant will in- into protrusive or any lateral excursion and lingual are often called offset crease the force by 20%. This increase because the incisal guide angle may be loads. The bone width decrease is pri- in force is further magnified by the Ն20°. Therefore, anterior implant marily from the facial aspect of the crown height. For example, a 12° an- crowns will be loaded at a consider- edentulous ridge. As a result, implants gle with a 100-N force will result with able angle during excursions, as com- are often placed more lingually than a 315-N mm force on a crown height pared to the long-axis position of the the center of the natural tooth root. of 15 mm.9 Maxillary anterior teeth implant. As a result, an increase in the This condition often results in a resto- are usually at an angle of Ն12° to the force to maxillary anterior implants ration cantilevered to the facial. When occlusal planes. Therefore, even im- should be compensated for, in the im- the available bone height is also de- plants placed in an ideal position are plant treatment plan. Most forces ap- creased, the CHS is increased. There- usually loaded at an angle. Maxillary plied to the osteointegrated implant

314 CROWN-HEIGHT SPACE GUIDELINES FOR IMPLANT DENTISTRY available bone and small crown The retention and resistance forms heights, and fewer implants with of an abutment for a cemented pros- higher crown heights in atrophied thesis are dramatically affected by the bone (Figs. 7 and 8). height of the abutment.2 The arc of The CHS increases when crestal displacement should be lower than the bone loss occurs around the implants. abutment height because the forces Therefore, an increased CHS may in- above the arc are in compression, crease the forces to the crestal bone while below the position of the arc, the around the implants and increase the forces are shear in nature. Materials risk of crestal bone loss. In turn, this such as cement, porcelain, and bone effect may further increase the CHS react strongest to compression and and moment forces to the entire sup- weakest to shear components of force. port system, and increase screw loos- ening, crestal bone loss, implant Existing Occlusal Vertical Dimension fracture, and/or implant failure. Be- To determine the interarch space, cause an increase in the biomechanical the overall issue of occlusal vertical forces is in direct relationship to the dimension (OVD) must be addressed. increase in CHS, the treatment plan of Therefore, the issues of CHS must be the implant restoration should con- considered after the development of sider stress-reducing options when- this dimension. The patient’s existing ever the CHS is increased. Methods to OVD should be evaluated early in decrease stress include:6 implant prosthetic treatment plan be- cause any modification will signifi- 1. Shorten cantilever length. cantly modify the overall treatment. 2. Less offset loads to the buccal or Not only will a change in OVD require lingual. at least 1 full arch to be reconstructed, 3. Increase the number of implants. Fig. 7. The original treatment plan for the it affects the CHS, and, therefore, the 4. Increase the diameters of implants. Brånemark protocol used fewer implants in potential number, size, position, less available bone (with higher CHS) and 5. Increase the surface area design of and/or angulation requirements of the more implants in abundant available bone implants. implants. The OVD is defined as the (with a smaller CHS). 6. Make removable restorations less re- Fig. 8. The effect of the crown height sug- distance between 2 points (i.e.,1in tentive and use soft tissue support. gests more implants should be inserted when the maxilla, and the other directly be- 7. Remove the removable restoration the CHS is high and fewer implants inserted low in the mandible) when the occlud- during sleeping hours to reduce the when the CHS is more ideal. ing members are in contact.5 This noxious effects of nocturnal para- dimension requires clinical evaluation function. of the patient and cannot be evaluated 8. Splint implants together, whether body are concentrated in the crestal solely on the diagnostic casts. they support a fixed or removable 7Ϫ9 mm of bone, regardless of im- The determination of the OVD is 10 prosthesis. plant design and bone density. There- not a precise process because a range fore, implant body height is not an A reduced CHS has biomechani- of OVD is possible without clinical effective method to counter the effect cal issues related to the strength of symptoms.11 At one time, it was be- of crown height. In other words, implant material and/or prosthetic lieved that the dimension of occlusion crown-root ratio is a prosthetic con- components, flexibility of the mate- was very specific and remained stable cept, which may guide the restoring rial, and retention requirement of the throughout a patient’s life. The OVD dentist when evaluating a natural tooth restoration. The fatigue strength of a position is not necessarily stable when abutment. However, the crown height- material is related to its diameter.8 For the teeth are present or after the teeth implant ratio is not a direct com- example, when a bar is one half as are lost. Long-term studies have parison. Crown height is a vertical thick in dimension, it is 8 times more shown that this is not a constant di- cantilever, which magnifies any lateral flexible. In fixed restorations, the mension and often is decreased over or cantilever force in either a tooth or movement of the material may time without clinical consequence, in an implant-supported restoration. increase porcelain fracture, screw either the dentate, partially edentulous, However, this condition is not im- loosening, and/or uncemented restora- or completely edentulous patient. In proved by increasing implant length. tions. Therefore, when reduced CHS fact, a completely edentulous patient The higher the CHS, the higher the exists, the material is much more often wears the same denture for more number of implants usually required likely to have complications. CHS- than 10 years, during which time the for the prosthesis, especially in the related issues are accentuated by an OVD is reduced Ն10 mm, without presence of other force factors.7 This excessive CHS that places more forces symptoms or patient awareness. is a complete paradigm shift as com- on the implant/prosthetic system, and The OVD may be altered perma- pared to the concepts advocated orig- reduced CHS makes the prosthetic nently without the symptoms of pain inally with many implants in more components weaker. and/or dysfunction. However, this is

IMPLANT DENTISTRY /VOLUME 14, NUMBER 4 2005 315 not to say altering the OVD has no creasing the OVD will often require sounds. Niswonger13 proposed the use consequence. A change in OVD af- restoration of all segments of the of the interocclusal distance (freeway fects the interarch distance between mouth, with the exception of the max- space), which assumes that the patient the arches. As such, it may affect the illary anterior teeth, if acceptable. relaxes the mandible into the same crown-to-root (implant) ratio and According to Kois and Phillips,11 constant physiologic rest position. The amount of biomechanical forces ap- there are primarily 3 times that a re- practitioner then subtracts 3 mm from plied to the support system of a pros- storing dentist should consider a mod- the measurement to determine the thesis. In addition, any change in the ification of the OVD: (1) esthetics, (2) OVD. There are 2 aspects that conflict OVD will also modify the horizontal function, and (3) structural needs of with this method as a primary factor. dimensional relationship of the max- the dentition. Esthetics is related to First, the amount of freeway space is illa to the mandible. As a result, the OVD for incisal edge positions, facial highly variable in the same patient, OVD difference will change the ante- measurements, and the occlusal plane. depending on several factors, includ- rior guidance, and the range of func- Function is related to the canine posi- ing head posture, emotional state, tion and esthetics. tions, the incisal guidance, and angle presence or absence of teeth, para- The most important effect of of load to teeth and/or implants. Struc- function, and time of recording OVD on tooth (implant) loading may tural requirements are related to di- (higher in the morning). Second, in- be the impact on the biomechanics of mensions of teeth for restoration, terocclusal distance at rest varies anterior guidance.12 The more closed while maintaining a biologic width. 3Ϫ10 mm from one patient to another. the OVD, the steeper the anterior As a result, the distance to subtract guidance and the higher the vertical Methods to Evaluate OVD from the freeway space is unknown overlap of the anterior teeth. These All the techniques used in tradi- for a specific patient. Therefore, the conditions will increase the forces to tional prosthodontics are also used to physiologic rest position should not be the anterior teeth and decrease the risk evaluate and/or establish the OVD. the primary method to evaluate OVD. of posterior interferences during ec- These techniques most often include Silverman14 stated that approxi- centric mandibular movements or the objective method of measuring fa- mately 1 mm should exist between the function. Opening the OVD has the cial dimensions, and/or the subjective teeth when the “S” sound is made. opposite effects. In general, for the methods of esthetics, resting arch po- Pound15 further developed this con- dentate patient, it is more risky to sition, and speaking space. There is no cept for the establishment of centric close an OVD than to open this dimen- consensus on the ideal method to ob- and vertical jaw relationship records sion because the mandibular anterior tain the OVD. Therefore, this dimen- for . Although this teeth may be positioned more facial, in sion is part art form and part science. concept is acceptable, it does not cor- a closer relationship to the maxillary Yet, it is critical enough that a final relate to the original OVD of the pa- teeth in centric occlusion. However, in treatment plan should not be rendered tient. Patients with dentures often completely edentulous patients re- until a determination has been made wear the same prosthesis for more stored with fixed implant prostho- relative to this dimension. than 14 years, and during this time, dontics, a change in OVD in either The maxillary anterior horizontal lose Ն10 mm of their original OVD. direction may have biomechanical and vertical tooth position is evaluated Yet, all these patients are able to say consequences. Opening the OVD and before any other segment of the “Mississippi” with their existing pros- decreasing the incisal guidance result- arches, including the OVD. If the thesis. If speech was related to the ing in a bilateral balanced occlusion maxillary anterior teeth are signifi- original OVD, these patients would may increase forces to posterior im- cantly malpositioned, the clinician not be able to pronounce the “S” plants in any mandibular excursion. should obtain further diagnostic stud- sounds because their teeth would be Closing the OVD may increase the ies, such as a cephalometric radio- more than 12 mm apart. Therefore, forces to anterior implants during any graph, to determine the relationship of speaking space should not be used as a excursion. On occasion, a change in the maxilla to the cranial base. The primary method to evaluate OVD. the OVD may also affect the sibilant patient may have unfavorable skeletal Kois and Phillips11 have noted that sounds of an individual because it also relationships, including vertical max- the subjective “esthetic” method to es- changes the horizontal position of the illary excess or deficiency. If the tablish an OVD is the most difficult to mandible. positions of the natural maxillary an- teach inexperienced dental students so The OVD is almost never natu- terior teeth are undesirable for any that it is least likely to be initially rally too large, and, unless some man- reason, orthodontics, orthognathic addressed when teaching the concepts made interference has been created, it surgery, and/or restoration may be of determining OVD. However, expe- is within clinical guidelines or de- indicated. Once the position of the rienced clinicians often consider this creased. Therefore, the restoring den- maxillary anterior teeth is acceptable, method to be a primary factor related tist most often should determine if the the next prosthetic guidelines require to OVD. Once the position of the max- OVD needs to be increased. In other the determination of the OVD. illary incisor edge is determined, the words, the existing OVD is a place to The subjective methods to deter- OVD influences esthetics of the face start the evaluation, not a position that mine OVD include the use of resting in general. necessarily must be maintained. This interocclusal distance and speech- Facial dimensions are directly re- is not a casual decision because in- based techniques using sibilant lated to the ideal facial esthetics of an

316 CROWN-HEIGHT SPACE GUIDELINES FOR IMPLANT DENTISTRY nardo da Vinci16 contributed several compared to give a clinical impression observations and drawings on facial of the accuracy with this objective ap- proportions, which he called “Divine proach. The subjective criteria of es- Proportions.” He observed that the thetics may then be considered after distance between the chin and bottom the facial dimensions are in balance of the nose was a similar dimension with each other. as: (1) the hairline to the eyebrows, (2) Radiographic methods to deter- the height of the ear, and (3) the eye- mine an objective OVD are also brows to the bottom of the nose (Fig. widely published in the literature. A 9). Each of these dimensions equaled cephalometric radiograph and tracing one third of the face. Many profes- are suggested when gross jaw excess sionals, including plastic surgeons, or deficiency is noted. These condi- oral surgeons, artists, orthodontists, tions may be caused from vertical and morticians, use facial measure- maxillary excess, vertical maxillary ments to determine OVD.17,18 A re- deficiency, vertical mandibular excess view of the literature by Misch19 found (long chin), vertical mandibular defi- many different sources that reveal ciency (short chin), apertognathia, many correlations of features that cor- and/or class II division II (deep bite) respond to the OVD, including: situations. Orthodontic treatment plan- ning of a dentate patient often includes 1. The horizontal distance between a lateral cephalogram and may be used the pupils. to evaluate OVD (glabella-subnasale, 2. The horizontal distance from the subnasale-menton). The same mea- outer canthus of 1 eye to the inner surements may be performed on the canthus of the other eye. edentulous patient (Fig. 11). 3. Twice the horizontal length of 1 Esthetics are influenced by OVD eye. because of its relationship to the max- 4. Twice the horizontal distance illomandibular positions. The smaller from the inner canthus of 1 eye to the OVD, the more class III the man- the inner canthus of the other eye. dibular jaw relationship becomes, and 5. The horizontal distance from the the higher the OVD, the more class II outer canthus of the eye to the ear. the mandible becomes. The maxillary 6. The horizontal distance from 1 16 anterior tooth position is first deter- Fig. 9. A drawing by Leonardo De Vinci sug- corner of the lip to the other, fol- mined and is most important for the gests the face has common measurements lowing the curvature of the mouth that are similar to the distance from the bot- esthetic criteria of the reconstruction. (cheilion to cheilion). tom of the nose to the bottom of the chin. Alteration of the OVD for esthetics 19 7. The vertical distance from the ex- Fig. 10. A review of the literature by Misch rarely includes the maxillary tooth po- ternal corner of the eye (outer found 11 measurements that were similar to sition. For example, the OVD position the OVD dimension. canthus) to the corner of the may be influenced by the need to Fig. 11. A lateral cephalogram may be used mouth. make the mandible less harsh looking to help evaluate the OVD in a dentate or 8. The vertical height of the eyebrow for a patient with a large chin button edentulous patient. to the ala of the nose. (mental protuberance). Once the OVD 9. The vertical length of the nose at satisfies the esthetic requirement of the midline (from the nasal spine individual and are able to be evaluated the prosthetic reconstruction, it may {subnasion} to the glabella point. regardless of the degree of experience still be slightly modified. For example, 10. The vertical distance from the of the clinician. Because facial dimen- the OVD may be modified to improve hairline to the eyebrow line. sions are an objective evaluation, the direction of force on the anterior 11. The vertical height of the ear. which is related to esthetics, it is usu- implants. In addition, anterior mandib- 12. The distance between the tip of ally the method of choice to evaluate ular implants on occasion are too fa- the thumb and tip of the index initially the existing OVD and/or es- cial to the incisal edge position, and finger when the hand lies flat, fin- tablish a different OVD during pros- increasing the OVD makes them much gers next to each other (Fig. 10). thetic reconstruction. The OVD based easier to restore. Therefore, because upon facial measurements may be per- All these measurements do not ex- the OVD is not an exact measurement, formed without the additional assis- actly correspond to each other but usu- the ability to alter this dimension, tance of radiography or other tests. ally do not vary by more than a few within limits, may often be beneficial. Facial measurements can be traced millimeters, with the exception of the back to antiquity, in which sculptors vertical height of the ear, when the and mathematicians followed the face has dimensional balance. By av- CONCLUSION “Golden Proportion,” later specified eraging several of these measure- Implant prostheses have a higher as a ratio of 1.618–1. Later on, Leo- ments, the existing OVD may be rate of mechanical complications than

IMPLANT DENTISTRY /VOLUME 14, NUMBER 4 2005 317 failure of an implant. A number of Disclosure Misch CE, ed. Contemporary Implant Den- factors may increase the mechanical The authors claim to have no finan- tistry. St. Louis, MO: Mosby; 1999:329- 343. load to an implant restoration, includ- cial interest in any company or any of 11. Kois JC, Phillips KM. Occlusal ver- ing an increased CHS. The CHS acts the products mentioned in this article. tical dimension: Alteration concerns. as a vertical cantilever to any angled Compend Contin Educ Dent. 1997;18: or offset load to the restoration. As a REFERENCES 1169-1174. 12. Keough B. Occlusal consider- result, excessive CHS should have 1. Goodacre CJ, Bernal G, Rung- stress reducing protocols, including ations in periodontal prosthetics. Int J Larassaerg K, et al. Clinical complications Periodontics Restorative Dent. 1992;12: shorter cantilever length, less offset with implants and implant prostheses. 359-371. loads, increased implant number, in- J Prosthet Dent. 2003;90:121-132. 13. Niswonger ME. The rest position of creased implant diameter, increased 2. Shillingburg HT, Hobo S, Whitsett LD. the mandible and centric relation. JAm In: Fundamentals of . surface area for implant designs, re- Dent Assoc. 1934;21:1572-1582. 2nd ed. Chicago, IL: Quintessence; 1981: 14. Silverman MM. Accurate measure- movable verses fixed restoration, 82-85. which are removed during sleep, and ment of vertical dimension by phonetics 3. Scurria M, Bader JD, Shugars DA. and the speaking centric space. Part I. splinting implants together. A reduced Meta-analysis of fixed partial denture Dent Dig. 1951;57:261-265. CHS also has mechanical conse- survival: Prostheses and abutments. 15. Pound E. Let/s/be your guide. quences to the restoration, including J Prosthet Dent. 1998;79:459-452. J Prosthet Dent. 1977;38:482-489. 4. Cruegers NHJ, Kayser DF, Van’t Hof 16. Leonardo da Vinci 1452–1519, An- reduced retention of the abutments MA. A meta-analysis of durability data on and an increased risk related to the atomical Studies. The anatomy of man conventional fixed bridges. Community from Queen Elizabeth II private collection; bending fracture resistance of the Dent Oral Epidermiol. 1994;22:448-452. Windsor Castle, UK, circa 1488. prosthesis. 5. Glossary of prosthodontic terms. 17. McGee GF. Use of facial measure- The CHS is affected by the OVD. J Prosthet Dent. 1999;81:39-110. ments in determining vertical dimension. Determination of the OVD is not a 6. Misch CE. Dental evaluation of the J Am Dent Assoc. 1947;35:342-350. implant candidate. In: Misch CE, ed. Den- 18. Mach MR. Facially generated oc- precise process, and a clinical range is tal Implant Prosthetics. Chicago, IL: possible without clinical symptoms. clusal vertical dimension. Compendium. Mosby; 2004. 1997;18:1183-1194. The existing OVD of a patient is rarely 7. Bidez MW, Misch CE. Force transfer 19. Misch CE. Objectives subjective naturally too large. A decrease in in implant dentistry: Basic concepts and methods for determine vertical dimensions OVD is more common in the complete principles. J Oral Implantol. 1992;18:264- of occlusion. Quintessence Int. 2000;31: 274. 280-281. edentulous patient. A modification of 8. Bidez MW, Misch CE. Clinical bio- the OVD may be made by the dentist mechanics in implant dentistry. In: Misch for esthetics, function, and/or struc- CE, ed. Contemporary Implant Dentistry. Reprint requests and correspondence to: tural needs of the dentition. The OVD St. Louis, MO: Mosby; 1993. Carl E. Misch, BS, DDS, MDS may be determined by objective or 9. Misch CE, Bidez MW. Implant pro- Suite 250 subjective methods. tected occlusion. In: Misch CE, ed. Con- 16231 Fourteen Mile Road temporary Implant Dentistry. St. Louis, Beverly Hills, MI 48025 These guidelines will appear as MO: Mosby; 1993. Phone: (248) 642-3199 Part 2 in the next issue of Implant 10. Misch CE, Bidez MW. A scientific Fax: (248) 642-3794 Dentistry. rationale for design. In: E-mail: [email protected]

318 CROWN-HEIGHT SPACE GUIDELINES FOR IMPLANT DENTISTRY Abstract Translations [German, Spanish, Portugese, Japanese]

AUTOR(EN): Carl E Misch, BS, DDS, Bericht der Podiumsdiskussion innerhalb der Konferenz zur Erzielung eines Konsens MDS*, Charles J. Goddaere, DDS, MSD**, in Bezug auf die Richtlinien der Abstandsho¨henbildung bei U¨ berkronungen fu¨r die Jon M. Finley, BA, DDS***, Craig M. Misch, Implantierungszahnheilkunde: Teil 1 DDS, MDS#, Mark Marinbach, CDT##, Tom Dabrowski, LDT, RDT###, Charles E. En- ZUSAMMENFASSUNG: Der internationale Kongress der Oralimplantologen (Interna- glish, DDSϩ, John C. Kois, DMD, MSDϩϩ, tional Congress of Oral Implantologists–ICOI) initiierte im Zeitraum vom 26. bis 27. Juni sowie Robert J. Cronin Jr., BS, DDS, 2004 in Las Vegas eine Konferenz zur Erzielung eines Konsens u¨ber die Abstandsho¨- MSϩϩϩ. *Professor und Direktor der oralen henbildung bei U¨ berkronungen. Das Gremium erhielt Gelegenheit, sich bereits im Vorfeld Implantologie, Temple Universita¨t, zahn- der Konferenz verschiedentlich sowie wa¨hrend und nach der Besprechung als Gruppe und medizinische Fakulta¨t, Philadelphia, PA, USA, unter den einzelnen Teilnehmern auszutauschen. Fu¨r die meisten Themenbereiche konnte CEO des Misch Internationalen Implan- keine u¨bereinstimmende Ansicht erzielt werden. Allerdings gelang es, allgemeine Rich- tierungsinstituts, Beverly Hills, MI, USA. tlinien in Bezug auf diesen Themenkomplex aufzustellen. Das nachfolgende Dokument **Dekan der zahnmedizinischen Fakulta¨t der stellt Teil 1 einer Zusammenfassung verschiedener dieser Richtlinien dar, die fu¨r die Loma Linda Universita¨t, Loma Linda, CA, Gesamtheit der Zahnheilkundigen von Vorteil sein ko¨nnen. USA.***Privat praktizierender Arzt, Prairie Village, KS, USA. #Klinischer A.O. Professor an der New Yorker Universita¨t, Abteilung fu¨r Implantatgestu¨tzte Zahnheilkunde, New York, NY, USA; privat praktizierender Arzt, Sara- sota, FL, USA. ##Assistenzprofessor der Tem- ple Universita¨t, zahnmedizinische Fakulta¨t, Pra¨sident der Nu-Life Long Island Zahnlabo- ratorien, West Hempstead, NY 15522. ###In- haber des BIT zahntechnischen Labors Pueblo, CO, USA. ϩKlinischer Assistenzpro- fessor der wiederherstellenden Zahnheilkunde der Universita¨t von Tennessee, Memphis, TN, USA und der Universita¨t von Oklahoma in Oklahoma City. ϩϩProfessor im Verbund des Graduiertenprogramms zur Wiederherstel- lungsforschung an der Universita¨t von Wash- ington, private praktizierender Arzt, Seattle, WA, USA. ϩϩϩLeiter des Programms fu¨r Zahnersatzkunde fu¨r Doktoranden und Profes- sor an der Universita¨t des Zentrums fu¨r Ge- sundheitsforschung in Texas, San Antonio, TX, USA. Schriftverkehr: Carl E. Misch, DDS, 16231 Fourteen Mile Road, Suite 250, Beverly Hills, MI 48025. Telefon: 248-642-3199, Fax: 248-642-3794 AUTOR(ES): Carl E. Misch, BS, DDS, 4 Informe del panel de una conferencia de consenso: Pautas para el espacio de la altura MDS*, Charles J. Goodacre, DDS, MSD**, de la corona para la odontologı´a de implantes: parte I Jon M. Finley, BA, DDS***, Craig M. Misch, DDS, MDS#, Mark Marinbach, CDT##, Tom ABSTRACTO: El Congreso International de Implanto´logos Orales (ICOI por sus siglas en Dabrowsky, LDT, RDT###, Charles E. En- ingle´s) patrocino´ una conferencia de consenso sobre el tema espacio de la altura de la glish, DDSϩ, John C. Kois, DMD, MSDϩϩ, corona entre el 26 y el 27 de junio del 2004 en Las Vegas, Nevada. El panel se comunico´ y Robert J. Cronin, Jr., BS, DDS, MSϩϩϩ. en varias ocasiones antes, durante y despue´s de la reunio´n, como grupo y como individuos. *Profesor y Director de Implantologı´a Oral, El consenso de una sola opinio´n no se logro´ en la mayorı´a de las cuestiones. Sin embargo, Temple University, Facultad de Odontologı´a, surgieron pautas generales relacionadas con el tema. El siguiente trabajo es la Parte I de Filadelfia, PA, EE.UU., Jefe Ejecutivo del un resumen de varias de las pautas que deberı´an ser de utilidad para la profesio´n en Misch International Implant Institute, Beverly general. Hills, MI, EE.UU. **Decano de la Facultad de Odontologı´a de Loma Linda University, Loma Linda, CA EE.UU. ***Pra´ctica Pri- vada, Prairie Village, KS, EE.UU. #Profesor Clı´nico Asociado de New York University, De- partamento de Odontologı´a de Implantes, Nueva York, NY, EE.UU., Pra´ctica Privada, Sarasota, FL, EE.UU. ##Profesor Asistente,

IMPLANT DENTISTRY /VOLUME 14, NUMBER 4 2005 319 Temple University, Facultad de Odontologı´a, Presidente de Nu-Life Long Island Dental Laboratories, West Hempstead, NY 15522. ###Duen˜o de BIT Dental Laboratory, Pueblo, CO, EE.UU. ϩProfesor Asistente Clı´nico de Odontologı´a de Restauracio´n de la Univer- sidad de Tennessee, Memphis, TN y University of Oklahoma en Oklahoma City. ϩϩProfesor Afiliado en el Programa de Restauracio´n para Graduados de la Universidad de Washington. Pra´ctica Privada, Seattle, WA, EE.UU. ϩϩϩDirector del Programa de Prostodo´n- tica Postdoctoral y Profesor del Centro de Ciencias de la Salud de la Universidad de Texas, San Antonio, TX, EE.UU. Correspon- dencia a: Carl E. Misch, DDS, 16231 Four- teen Mile Road, Suite 250, Beverly Hills, MI 48025. Tele´fono: 248-642-3199, Fax: 248- 642-3794.

AUTOR(ES): Carl E. Misch, Bacharel em Relato´rio do Painel da Confereˆncia de Consenso: Diretrizes de Espac¸o de Altura da Cieˆncia, Cirurgia˜o-Dentista, Me´dico*, Charles Coroa para Odontologia de Implante: Parte I J. Goodacre, Cirurgia˜o-Dentista, Me´dico**, Jon M. Finley, Bacharel em Letras, Cirurgia˜o- RESUMO: O Congresso Internacional de Implantologista Oral (ICOI) patrocinou uma Dentista***, Craig M. Misch, Cirurgia˜o- confereˆncia de consenso sobre o to´pico de Espac¸o de Altura da Coroa em 26-27 de junho Dentista, Me´dico#, Mark Marinbach, Te´cnico de 2004, em Las Vegas, Nevada. O painel comunicou em va´rias ocasio˜es antes, durante Denta´rio##, Tom Dabrowsky, Te´cnico Den- e apo´s da reunia˜o, tanto como grupo quanto entre indivı´duos. Um consenso de uma ta´rio###, Charles E. English, Cirurgia˜o- opinia˜o na˜o foi desenvolvido para a maioria das questo˜es. Contudo, diretrizes gerais Dentistaϩ, John C. Kois, Me´dico, Mestre em emergiram, relacionadas ao to´pico. O seguinte artigo e´ a Parte I de um resumo de va´rias Cieˆnciaϩϩ e Robert J. Cronin, Jr. Bacharel das diretrizes que deveriam ser de benefı´cio para a profissa˜o em geral. em Cieˆncia, Cirurgia˜o-Dentista, Mestre em Cieˆnciaϩϩϩ. *Professor e Diretor de Im- plantologia Oral, Temple University, Facul- dade de Odontologia, Filade´lfia, 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. ***Clı´nica Particular, Prairie Village, KS, EUA. #Profes- sor Clı´nico Associado na Universidade de Nova York, Departamento de Odontologia de Implante, Nova York, NY, EUA, Clı´nica Par- ticular, Sarasota, FL, EUA. ##Professor As- sistente da Temple University, Faculdade de Odontologia, Presidente dos Laborato´rios Denta´rios Nu-Life, de Long Island, West Hempstead, NY 15522. ###Proprieta´rio do Laborato´rio Denta´rio BIT, Pueblo, CO, EUA. ϩProfessor Assistente Clı´nico de Odontologia Restauradora da Universidade do Tennessee, Memphis, TN, EUA e Universidade de Okla- homa em Oklahoma City. ϩϩProfessor Afili- ado no Programa Graduado Restaurador na Universidade de Washington, Clı´nica Partic- ular, Seattle, WA, EUA. ϩϩϩDiretor do Programa de Prostodoˆntica em Nı´vel de Po´s- Doutorado e Professor do Centro de Cieˆncias da Sau´de da Universidade do Texas, San An- tonio, TX, EUA. Correspondeˆncia para: Carl E. Misch, Cirurgia˜o-Dentista, 16231 Fourteen Mile Road, Suite 250, Beverly Hills, MI 48025. Telefone: 248-642-3199, Fax: 248-642-3794.

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