EstheticsinanteriorfixedbridgeprosthodonticsGeorgeM.Moulton, D.D.S., Atlanta, Ga.Objcctives of crown and bridge prosthe-on the original contour of the tooth andsis are restoration of function and thewill bearesult of thatcontour ratherthanrestoration of esthetics.This paper re-of the initial attempt to establish thisviews and emphasizessome of themorelabial margin. It must be kept in mindimportant points in the achievement ofthat flat, rigid disks are being utilized toan esthetic replacement in anterior fixedproduce these cuts. If, for example, anattempt is made to establish the marginbridge prosthodontics.toward the gingiva in a self-cleansingarea, this ffat rigid disk will overextendPREPARATION OF ABUTMENTthe margin at the incisal third. This ex-The success of a restoration starts withplains why many times an unnecessaryamount of gold is displayed at the incisalthe preparation of the abutment; this isobvious when failures and successes arethird from the labial aspect.analyzed from an esthetic point of view.After the procedure has been com-pleted to the point of preparing theA few points regarding the selection ofmesial and distal resistance grooves, thethe retainer and its preparation will bepractitioner returns to the labial margin.considered.Thethree-quartercrownisWhether or not an incisal resistanceperhaps the most widely used retainer forupper anterior abutments. Although itgroove has been used, the starting pointof the mesial and distal grooves is ap-has its limitations, it satisfies to a greatextent the requirements of a retainer. Itproximately the same. These grooves arcis in its preparation, however, that theprepared parallel with the labial incisaltwo-thirds. This will provide the longestpractitioner may go amiss (Fig. 1, left)particularly in the mesial and distal slicespossible grooves and will, generally,avoidthe mesial and distal concavities. Thesewhich usually are the first steps of thispreparation.grooves will,however,be"tucked in"beInsofar as possible, the characteristichind thelabial line angles.Insofar ascontourof thetoothfrom thelabialas-possible the dentist is actually establish.pectmust bemaintained;thatis,fromaing the labial margin of the preparationlabial aspect the tooth should still retainwith the labial wall of these grooves, soits square, ovoid or tapering contours.that not only the direction of the grooveStated another way, the mesial and distalbut the eventual esthetics resulting fromslices should reduce only the height ofthis preparation may be controlled.contour and there should be no attemptwith the mesial and distal slices to estab-P:esented before the sectionon partial_prosthodontics.lish the labial margins of the preparation.ninety-fifthanDentalAssociasession,tion,Miami,Fia.,November 9,1954.The extent to which the labial margin isChairmap,crown.and,bridge prosthesis,School ofproduced with these slices depends onlyDentistry,EmoryUniversity.36
Esthetics in anterior fixed bridge prosthodontics George M . M ou lton , D .D .S ., Atlanta, Ga. Objectives of crown and bridge prosthesis are restoration of function and the restoration of esthetics. This paper reviews and emphasizes some of the more important points in the achievement of an esthetic replacement in anterior fixed bridge prosthodontics. PREPARATION OF ABUTMENT Th e success of a restoration starts with the preparation of the abutment; this is obvious when failures and successes are analyzed from an esthetic point of view. A few points regarding the selection of the retainer and its preparation w ill be considered. Th e three-quarter crown is perhaps the most widely used retainer for upper anterior abutments. Although it has its limitations, it satisfies to a great extent the requirements of a retainer. It is in its preparation, however, that the practitioner may go amiss (Fig. 1, left) particularly in the mesial and distal slices which usually are the first steps of this preparation. Insofar as possible, the characteristic contour of the tooth from the labial aspect must be maintained; that is, from a labial aspect the tooth should still retain its square, ovoid or tapering contours. Stated another way, the mesial and distal slices should reduce only the height of contour and there should be no attempt with the mesial and distal slices to establish the labial margins o f the preparation. Th e extent to which the labial margin is produced with these slices depends only on the original contour of the tooth and w ill be a result of that contour rather than of the initial attempt to establish this labial margin. It must be kept in mind that flat, rigid disks are being utilized to produce these cuts. If, for example, an attempt is made to establish the margin toward the gingiva in a self-cleansing area, this flat rigid disk w ill overextend the margin at the incisal third. This explains why many times an unnecessary amount of gold is displayed at the incisal third from the labial aspect. A fter the procedure has been completed to the point of preparing the mesial and distal resistance grooves, the practitioner returns to the labial margin. W hether or not an incisal resistance groove has been used, the starting point of the mesial and distal grooves is approximately the same. These grooves are prepared parallel with the labial incisal two-thirds. This w ill provide the longest possible grooves and will, generally, avoid the mesial and distal concavities. These grooves will, however, be “ tucked in” behind the labial line angles. Insofar as possible the dentist is actually establishing the labial margin of the preparation with the labial wall of these grooves, so that not only the direction of the groove but the eventual esthetics resulting from this preparation may be controlled. P.esented before the section on partial prosthodontics, ninety-fifth annual session, Am erican Dental A ssociation, M ia mi, Fla., Novem ber 9, 1954. Chairm an, crown and brid ge prosthesis, School of Dentistry, Emory University. 36
MOULTON..VOLUME52,JANUARY1956.37the distal surfaces do not. In attemptingOne other point concerning estheticsshould be emphasized: it is not necessaryto prepare both the mesial and distalto show any gold on the incisal edge. Thesurfaces, the esthetic objective of replace-preparation of the incisal edge should bement may be defeated. Also, in instancesaccomplished on a bevel toward the lin-where teeth are slightly tipped or rotatedgual surface and this bevel should starttwo slices can be made, one on each oifrom the height of contour of the incisalthe abutments, and the line of insertioredge. Again, this should result in almostdirected without the overreduction oftotal hiding of the gold from the directone or more surfaces so that the prosthe-labial view.sis may be inserted;in other words, toWhether an incisal resistance groove ismake four parallel slices frequently leadsto unesthetic results.to be used will depend on the labiolin-There are instances where the placinggual bulk on the incisal edge. If the toothof even onc slice for a preparation im-is too thin labiolingually, the placementof a resistance groove will, of course, re-pairs rather than enhances a result:forexample, in the short, bulky teeth whichsult in discoloration about the margins ofdo not allow for adequate resistancethe crown from a labial aspect within agrooves in either the mesial or distalfew months after cementation. This bulksurfaces. In such instances, it is possibleis adcquate in a majority of cases, and itthat the retainer should be the three-pinis improper preparation of the lingualhood (Fig. 1, right). When this retainersurface toward the incisal edge after theaccomplishment of the incisal bevel whichis supplemented with trusses on the lin-gual surface to provide for the necessaryresults in inadequate bulk for the resist-rigidity of the casting, it has many val-ance groove,A good rule to follow in many prepara-uable uses in fixed prosthesis.tions is to remove a uniform amountthroughout; thereby, the original con-PROBLEMS OF SPACINGtours of the teeth can be retained in manyThere are other details in the construc-instances. If, however, this bulk is in-tion of anterior fixed bridgework whichadequate, the use of a lingual step or ofare worth emphasizing.It is necessary attrusses must be considered in order totimes to place a facing where the spaceprovide the required rigidity in castings.If a fixed prosthesis is to be furnishedsecms too small. If such a facing werethe patient, the operator cannot limitplaced within the space it would be un-esthetic because the harmonious effecthimself to the use of the three-quarterwould be lost. The dentist must keep incrown and meet the requirements of amind that an esthetic effect means har-fixed prosthesis, either esthetically or inmony in contour and color, and thatrelation to retention of the prosthesis.Other types of retainers must be selectedthere are many things which go to makewhich better answer the individual needs.up this effect.In the example shown inFigure 2, above, the space does not seemThe modified three-quarter crown is onelarge enoughfor placement of a facing.which has been found to be invaluableHowever,it ispossibleto placethis fac-(Fig. 1, center). This is the preparationing so that it overlaps slightly the adja-which utilizes one resistance groove, ancent abutments and carries out irregu-incisal pin and a lingual pin for reten-larities which are already apparent intion. There are many instances in whichthe mouth; thus harmony is achieved.its use is preferable to that of the three-The incisal opaque staining should requarter crown. In some ovoid teeth theproduce any or all white opaque, brownmesial surfaces often lend themselves toor other inperfections.an adequate resistance groove, whereas
M O U LTO N . . . VO LU M E 52, JA N U A R Y 1956 • 37 One other point concerning esthetics should be emphasized: it is not necessary to show any gold on the incisal edge. The preparation o f the incisal edge should be accomplished on a bevel toward the lingual surface and this bevel should start from the height of contour of the incisal edge. Again, this should result in almost total hiding of the gold from the direct labial view. Whether an incisal resistance groove is to be used will depend on the labiolingual bulk on the incisal edge. I f the tooth is too thin labiolingually, the placement of a resistance groove will, of course, result in discoloration about the margins of the crown from a labial aspect within a few months after cementation. This bulk is adequate in a m ajority o f cases, and it is improper preparation o f the lingual surface toward the incisal edge after the accomplishment o f the incisal bevel which results in inadequate bulk for the resistance groove. A good rule to follow in many preparations is to remove a uniform amount throughout; thereby, the original contours o f the teeth can be retained in many instances. If, however, this bulk is inadequate, the use of a lingual step or of trusses must be considered in order to provide the required rigidity in castings. I f a fixed prosthesis is to be furnished the patient, the operator cannot limit himself to the use of the three-quarter crown and meet the requirements o f a fixed prosthesis, either esthetically or in relation to retention o f the prosthesis. Other types of retainers must be selected which better answer the individual needs. T h e modified three-quarter crown is one which has been found to be invaluable (Fig. 1, center). This is the preparation which utilizes one resistance groove, an incisal pin and a lingual pin for retention. There are many instances in which its use is preferable to that o f the threequarter crown. In some ovoid teeth the mesial surfaces often lend themselves to an adequate resistance groove, whereas the distal surfaces do not. In attempting to prepare both the mesial and distal surfaces, the esthetic objective of replacement may be defeated. Also, in instances where teeth are slightly tipped or rotated, two slices can be made, one on each of the abutments, and the line of insertion directed without the overreduction of one or more surfaces so that the prosthesis may be inserted; in other words, to make four parallel slices frequently leads to unesthetic results. There are instances where the placing of even one slice for a preparation im pairs rather than enhances a result; for example, in the short, bulky teeth which do not allow for adequate resistance grooves in either the mesial or distal surfaces. In such instances, it is possible that the retainer should be the three-pin hood (Fig. 1, righ t). W hen this retainer is supplemented with trusses on the lingual surface to provide for the necessary rigidity of the casting, it has many valuable uses in fixed prosthesis. PROBLEMS OF SPACING There are other details in the construction of anterior fixed bridgework which are worth emphasizing. It is necessary at times to place a facing where the space seems too small. I f such a facing were placed within the space it would be unesthetic because the harmonious effect would be lost. T h e dentist must keep in mind that an esthetic effect means harmony in contour and color, and that there are many things which go to make up this effect. In the example shown in Figure 2, above, the space does not seem large enough for placement o f a facing. However, it is possible to place this facing so that it overlaps slightly the adjacent abutments and carries out irregularities which are already apparent in the m outh; thus harmony is achieved. T h e incisal opaque staining should reproduce any or all white opaque, brown or other inperfections
38THEJOURNALOFTHEAMERICANDENTALASSOCIATIONFig.I :Left: Preparation for a three-guarter crown.Center:Preparation for a modified three-quarter crown.Right: The three-pin hood (Courtesy of J. Raymond Gill, School of Dentistry,Universityof California)Another detail is the refining of theers have been prepared and temporarilyretainers justprior to takingtheimpres-seated prior to obtaining this movementsions for the working model. The excessIn the example shown, after the centralbulk of gold on the mesial, distal andincisor had been brought into contactwith the adjacent incisor, impressions forincisal surfaces after casting must be re-duced. This should not be done on thethe working model were taken, and theworking models as it is not possible tobridge acted as an absolute retainer afterget the proper perspective on thesethe orthodontic movement. The impor-models.The reduction will accomplishtance of consultation with the orthodon-many things.It will provide for themaxi-tist and use of orthodontic appliancesmum space intowhich the facing can bewhen preparing a mouth for a bettenground and will, to a great extent, ob-prosthesis cannotbe overemphasized.Ifliterate the gold margin of the retainerhowever, spaces exist generally through-and the soldered connector from theout the anterior region, it is not desirablelabial view.The importance of this reto closeany space.A type of connectorduction cannot beoveremphasizedItmust be used that will maintain the spaceshould also be stresscd that the facingor diastema. The bar type connectorselected should be slightly large, if any-shown in Figure 2,below,provides anesthetic result. Occasionally,it is possiblething, for the space. Such a facing willprovide for the necessary bulk of porce-touseabartypeofconnectortoconnecttheponticwith both retainers.Thisgiveslain for its preparation, and it can thenbe spot ground into position and shapeda normal appearance of space betweento harmonize with the abutments.teeth rather than filling in the space withIn many instances, one or more of thean unsightly solder connector.These bars,however, must be rigid enoughto standabutments have moved because of theloss of an adjacent tooth.Orthodonticthe stress to which the prosthesis will betreatment is indicated to reestablish nor-subjected; furthermore, they must bemal alignment (Fig. 2, center). Retain-just off the supporting tissue so that floss
38 • THE JO U R N A L OF THE A M E R IC A N DENTAL A S SO C IATIO N Fig. I • h eft: Preparation for a three-quarter crown. Center: Preparation for a modified threequarter crown. Right: The three-pin hood (Courtesy of J. Raymond Gill, School of Dentistry, University of California) Another detail is the refining of the retainers just prior to taking the impressions for the working model. Th e excess bulk of gold on the mesial, distal and incisal surfaces after casting must be reduced. This should not be done on the working models as it is not possible to get the proper perspective on these models. T h e reduction will accomplish many things. It will provide for the maximum space into which the facing can be ground and will, to a great extent, obliterate the gold margin of the retainer and the soldered connector from the labial view. Th e importance of this reduction cannot be overemphasized. It should also be stressed that the facing selected should be slightly large, if anything, for the space. Such a facing will provide for the necessary bulk of porcelain for its preparation, and it can then be spot ground into position and shaped to harmonize with the abutments. In many instances, one or more o f the abutments have moved because o f the loss of an adjacent tooth. Orthodontic treatment is indicated to reestablish normal alignment (Fig. 2, center). Retainers have been prepared and temporarily seated prior to obtaining this movement. In the example shown, after the central incisor had been brought into contact with the adjacent incisor, impressions for the working model were taken, and the bridge acted as an absolute retainer after the orthodontic movement. Th e im portance of consultation with the orthodontist and use of orthodontic appliances when preparing a mouth for a better prosthesis cannot be overemphasized. If, however, spaces exist generally throughout the anterior region, it is not desirable to close any space. A type of connector must be used that will maintain the space or diastema. Th e bar type connector, shown in Figure 2, below, provides an esthetic result. Occasionally, it is possible to use a bar type of connector to connect the pontic with both retainers. This gives a normal appearance of space between teeth rather than filling in the space with an unsightly solder connector. These bars, however, must be rigid enough to stand the stress to which the prosthesis w ill be subjected; furthermore, they must be just off the supporting tissue so that floss
MOULTONVOLUME52,JANUARY195639aration of this facing for its backing is,may be passed underneath the bar forof course, a requirement. A long-pin fac-proper cleansing.In any discussion of esthetics, the con-ing allows for the protection of the in-cisal edge.If the same approach is usedsideration of thetype of porcelainre-placementsutilized cannot be omitted.as in the preparation of the three-quarterThe author believes that the most es-crown, it is not necessary to show anyof gold from the labial aspectthetic facing is the long-pin porcelainamountfacing.In the past, inadequacies in por-Thesefacan be arranged in anycelain facings have been due,principally,atedfor theindividual patientto the lack of condensation of the porwill produce the artistic resultcelain.The newvacuum-fired pin facingsso much desired (Fig.3, above)nowavailablearewell condensed andAnotheanomaly is the instance inhave the desired strength.Proper prepwhich there is morethanthe normalFig.2.Above: The placement of upper right central incisor where space is inadequate andirregularities exist. Center: Simpleorthodontic treatment used to close space between lateralincisors. Below: The bar type connector used to maintain normal space between central incisors
M O U LTO N . . . VO LU M E 52, JAN U A R Y 1956 • 39 may be passed underneath the bar for proper cleansing. In any discussion of esthetics, the consideration o f the type o f porcelain replacements utilized cannot be omitted. Th e author believes that the most esthetic facing is the long-pin porcelain facing. In the past, inadequacies in porcelain facings have been due, principally, to the lack o f condensation of the porcelain. T h e new vacuum-fired pin facings now available are well condensed and have the desired strength. Proper preparation of this facing fo r its backing is, of course, a requirement. A long-pin facing allows for the protection of the incisal edge. I f the same approach is used as in the preparation of the three-quarter crown, it is not necessary to show any amount of gold from the labial aspect. These facings can be arranged in any way indicated for the individual patient and they will produce the artistic result so much desired (Fig. 3, above). Another anomaly is the instance in which there is more than the normal Fig. 2 • A bove: T he placement of upper right central incisor where space is inadequate and irregularities exist. Center: Simple orthodontic treatment used to close space between lateral incisors. Below: The bar type connector used to maintain normal space between central incisors
4O·THEJOURNALOFTHEAMERICANDENTALASSOCIATIONspace for a single missing tooth, whichbe obvious, however, that if there isaprovides space for two replacements in-deep overbite with little or no overjet, thestead of for only the one which is miss-problemof replacement becomes coming.Suchananomalypresents anplex. The central incisor must certainlyexcellent chance for the dentist to usethen be considered for use as an abutingenuity. Figure 3, center and belowment.left, shows an example in which the abut-ments are the upper left central incisorESTHETICS OF THE FULL-VENEERand the upper right lateral incisor, theRETAINERupper right central incisor having beenlost.If anattemptweremadetoplaceTheproblem of theanterior replacementthe missing central incisor in this space,cannot be left without discussing theit would obviously produce an unestheticnecd for a full-veneer retainer to obtainresult, If a central and a lateral incisoran esthetic result. This need is apparentwereplaced inthis space it would lookfor mouths in which extensive restora-from the labial aspect as if there weretions involve a good deal of the labialtwo lateral incisors on the right side, andsurfaces, or for those which presentthis would create lack of symmetry. Theanomalies of form or color which muslateral incisor that is the abutment in thisbe corrected to produce a pleasing re-instance obviously occupies the positionsult. Many patients are satisfied with theof the upper right cuspid. Therefore, toporcelain jacket crown which is and al.prodluce the desired harmony, this upperways has been the most esthetic restora-right lateral incisor must be prepared ontion.Of late, however, many schools areits incisal edge to simulate a cuspid. Theomitting the construction of the por-right lateral incisor now harmonizes withcelain restoration from the training andthe left cuspid and symmetry has beenothers are content with teaching therestored to the upper anterior segment.placement of one such restoration. ThisOne of the replacements most fre-is woefully inadequate training for thequently needed in the anterior mouth isyoung dentist who may wish to prescribeprobably the lost lateral incisor (Fig. 3,a porcelain restoration.below right). It is the author's opinionIn addition, the widespread use ofthat this is the one instance in which theacrylic resins in dentistry has caused aswing bridge" can and should be utilized.severe setback in the use of porcclainObservation will show that this type ofThere must be a re-evaluation of teach-construction frequently renders the long-ing and ideas relative to the use of theseest service of all fixed prostheses. Thetwo materials. Certainly, for the unittype referred to is strictly a single bridgerestoration, if the conditions are favor-replacement and does not have any at-able, particularly the occlusion, the por-tachment or arm on the adjacent centralcelain jacket is by far the best restoration.incisor. In such instances,judgmentAt the same time, the limitations of anymust be used in the treatment planning.material must be realized. Porcelain isIf the central incisor is involved withbrittle and will not stand undue stress.caries or restorations, it might be con-Therefore, in patients who have a deepsidered for use as an abutment.Probablyoverbite and little or no overjet in themore important,however,is the studyofanterior region of the mouth, the use of athe occlusion. If there is a normal over-full porcelain crown is contraindicated.bite-overjet relationship, this type of con-In such instances, failure would result,struction will serve very well; it willwith a fracture of the porcelain acrossalso where there is more than normalthe area of the cingulum. Under suchoverjet with little or no overbite. It shouldcircumstances a more durable type of
40 • THE JO U R N A L O F THE A M E R IC A N DENTAL AS S O C IA TIO N space for a single missing tooth, which provides space for two replacements instead of for only the one which is missing. Such an anomaly presents an excellent chance for the dentist to use ingenuity. Figure 3, center and below left, shows an example in which the abutments are the upper left central incisor and the upper right lateral incisor, the upper right central incisor having been lost. I f an attempt were made to place the missing central incisor in this space, it would obviously produce an unesthetic result. I f a central and a lateral incisor were placed in this space it would look from the labial aspect as if there were two lateral incisors on the right side, and this would create lack of symmetry. T h e lateral incisor that is the abutment in this instance obviously occupies the position of the upper right cuspid. Therefore, to produce the desired harmony, this upper right lateral incisor must be prepared on its incisal edge to simulate a cuspid. The right lateral incisor now harmonizes with the left cuspid and symmetry has been restored to the upper anterior segment. One of the replacements most frequently needed in the anterior mouth is probably the lost lateral incisor (Fig. 3, below righ t). It is the author’s opinion that this is the one instance in which the “ wing bridge” can and should be utilized. Observation w ill show that this type of construction frequently renders the longest service of all fixed prostheses. Th e type referred to is strictly a single bridge replacement and does not have any attachment or arm on the adjacent central incisor. In such instances, judgment must be used in the treatment planning. I f the central incisor is involved with caries or restorations, it might be considered for use as an abutment. Probably more important, however, is the study of the occlusion. I f there is a normal overbite-overjet relationship, this type o f construction w ill serve very w ell; it will also where there is more than normal overjet with little or no overbite. It should be obvious, however, that if there is a deep overbite with little or no overjet, the problem of replacement becomes complex. T h e central incisor must certainly then be considered for use as an abutment. ESTHETICS OF TH E FULL-VENEER RETAINER Th e problem of the anterior replacement cannot be left without discussing the need for a full-veneer retainer to obtain an esthetic result. This need is apparent for mouths in which extensive restorations involve a good deal of the labial surfaces, or for those which present anomalies of form or color which must be corrected to produce a pleasing result. M any patients are satisfied with the porcelain jacket crown which is and always has been the most esthetic restoration. O f late, however, many schools are omitting the construction of the porcelain restoration from the training and others are content with teaching the placement of one such restoration. This is woefully inadequate training for the young dentist who may wish to prescribe a porcelain restoration. In addition, the widespread use of acrylic resins in dentistry has caused a severe setback in the use o f porcelain. There must be a re-evaluation of teaching and ideas relative to the use of these two materials. Certainly, for the unit restoration, if the conditions are favorable, particularly the occlusion, the porcelain jacket is by far the best restoration. A t the same time, the limitations o f any material must be realized. Porcelain is brittle and w ill not stand undue stress. Therefore, in patients who have a deep overbite and little or no over jet in the anterior region o f the mouth, the use of a full porcelain crown is contraindicated. In such instances, failure would result, with a fracture of the porcelain across the area o f the cingulum. U nder such circumstances a more durable type of
MOULTON....VOLUME52,JANUARY1956.4restoration is indicated; one which will,face portion is cut out prior to castingatthe sametime,accomplish the objec-Inadequately shown in the illustrationtivesof esthetics.Arestorationinwhicharetheundercutsonthemesial anddistalacrylic resin is used is shown in Figure 4.sidesforretentionoftheacrylicmaterialThis type of restoration provides for fullThe crown is of the open-face type; thatis, with a shoulder on the labial, mesialgold coverage of the preparation.This isand distal sides of the tooth, After theimportant in several ways.First, in procompleteblueinlaywaxup,theopen-viding for full gold coverage, cement isFig.3Above:Estheticarrangement of upperfouranterior long-pinfacings.Centerand belotleft:Theincisal edgeoftheupperright lateral incisor has been preparedas acuspid toproduceSymmetry. Below right:Wing bridge replacing upper right lateral incisor with no connectorto upperright central incisorj modified three-quarter crown usedasretainer on cuspid
M O U LTO N . . . VO LUM E 52, JA N U A R Y 1956 • 41 restoration is indicated; one which will, at the same time, accomplish the objectives of esthetics. A restoration in which acrylic resin is used is shown in Figure 4. T h e crown is of the open-face type; that is, with a shoulder on the labial, mesial and distal sides of the tooth. A fter the complete blue inlay waxup, the openface portion is cut out prior to casting. Inadequately shown in the illustration are the undercuts on the mesial and distal sides for retention of the acrylic material. This type of restoration provides for full gold coverage of the preparation. This is important in several ways. First, in providing for full gold coverage, cement is Fig. 3 • A bove: Esthetic arrangement of upper four anterior long-pin facings. Center and below left: T he incisal edge of the upper right lateral incisor has been prepared as a cuspid to produce symmetry. Below right: Wing bridge replacing upper right lateral incisor with no connector to upper right central incisor; modified three-quarter crown used as retainer on cuspid
42THE JOURNALOFTHEAMERICAN DENTALASSOCIATIONto imply that bulk is of no consequence,but the bulk depends on the properpreparation for this type of jacket orcrown.The requirements for this, how-ever, donot differ from therequirementsfor the full-porcelain veneer.Thethinnest possible cast veneer covering thestump in the open-face portion of therestoration usually will provide adequatebulk for the acrylic material.The authorhas not found masking materials of anysignificance and does not use them. ThisFig.4 .Models showing procedure from thetype of restoration is useful when the oc-blue inlay waxup stage with cutout, the cast-clusion is unfavorable to porcelain. An-ing, the white ivory waxup and the completeothertypeof open-facecrownthatgold-acrylic combination open-facecrownachieves an esthetic result, is, of course,one made of porcelain instead of acrylicresin. The porcelain restoration, however,not placed adjacent to the acrylic veneer.has been well covered in the dentalSecondly, there are no pressures appliedliterature.to the acrylic resin on cementation thatmight tend to break the acrylic resinOPEN-FACEACRYLIC CROWNloosefrom its undercuts and cause leak-The open-face acrylic crown can be usedage between the acrylic resin and its goldboth as a unit restoration and as a re-retainer. The net result is adequate reten-tion for the acrylic resin and stability oftainer in fixed prosthesis. There shouldcolor. After casting,all margins andbe no hesitation in using this type of re-shoulders should be polished, but not thetainer adjacent to a porcelain pin facing,open-face portion of the crown.as the same harmonious effect can beWhite ivory wax is then used to waxproduced whether the adjacent teeth areup the open-face portion. This must benatural or have porcelain facings. Anexample of this is shown in Figure5, firstdone in the mouth. No model is adequatefor this procedure.Many excellentrow.The amount of the protection of thearticles have discussed color in anteriorincisal edge should be determined, ofrestorations.Beforesuccesscanbecourse, in each individual instance. Ifachieved with this type of restoration,there is an end-to-end occlusion, the goldthe operator must be aware that colorshould fully cover the incisal edge. Toinvolves many things.He must becomeachieve an esthetic result in the unitextremely conscious of contour and allrestoration, the adjacent teeth again mustlabial markings that produce contour.be considered. If the adjacent teeth haveThe highlights are what differentiate oneinterproximal foils or three-quartertype of contour from another; that is, therestorations with gold showingcrowntapering ovoid and square.from the labial aspect, the restorationThereforethe contour and all labial markings of theshouldbeconstructed to harmonize.adjacent teeth must be reproduced toThismeansthatitisnecessary sometimesattain aharmonious effectin therestorato provide for the imitation of gold foilstion. Only if there is exactness in theor three-quarter crowns when cutting outreproduction will the restorationblendfor the acrylic veneer.Esthetic resultsin with the adjacent teeth and achieveare in direct proportion to attention todetails.good matching color.This does not mean
« • THE JO U R N A L OF THE A M E R IC A N DENTAL AS SO C IATIO N Fig. 4 • M odels showing procedure from the blue inlay waxup stage with cutout, the casting, the white ivory waxup and the complete gold-acrylic combination open-face crown not placed adjacent to the acrylic veneer. Secondly, there are no pressures applied to the acrylic resin on cementation that might tend to break the acrylic resin loose from its undercuts and cause leakage between the acrylic resin and its gold retainer. Th e net result is adequate retention for the acrylic resin and stability of color. A fter casting, all margins and shoulders should be polished, but not the open-face portion o f the crown. W hite ivory wax is then used to wax up the open-face portion. This must be done in the mouth. N o model is adequate for this procedure. M any excellent articles have discussed color in anterior restorations. Before success can be achieved with this type of restoration, the operator must be aware that color involves many things. H e must become extremely conscious of contour and all labial markings that produce contour. Th e highlights are what differentiate one type of contour from another; that is, the tapering ovoid and square. Therefore, the contour and all labial markings of the adjacent teeth must be reproduced to attain a harmonious effect in the restoration. Only if there is exactness in the reproduction w ill the restoration blend in with the adjacent teeth and achieve good matching color. This does not mean to imply that bulk is of no consequence, but the bulk depends on the proper preparation for this type of jacket or crown. The requirements for this, however, do not differ from the requirements for the full-porcelain veneer. Th e thinnest possible cast veneer covering the stump in the open-face portion of the restoration usually will provide adequate bulk for the acrylic material. Th e author has not found masking materials of any significance and does not use them. This type of restoration is useful when the occlusion is unfavorable to porcelain. A n other type of open-face crown that achieves an esthetic result, is, of course, one made o f porcelain instead o f acrylic resin. The porcelain restoration, however, has been well covered in the dental literature. OPEN-FACE ACRYLIC CROWN Th e open-face acrylic crown can be used both as a unit restoration and as a retainer in fixed prosthesis. There should be no hesitation in using this type of retainer adjacent to a porcelain pin facing, as the same harmonious effect can be produced whether the adjacent teeth are natural or have porcelain facings. An example of this is shown in Figure 5, first row. The amount of the protection of the incisal edge should be determined, of course, in each individual instance. If there is an end-to-end occlusion, the gold should fully cover the incisal edge. T o achieve an esthetic result in the unit restoration, the adjacent teeth again must be considered. I f the adjacent teeth have interproximal foils or three-quarter crown restorations with gold showing from the labial aspect, the restoration should be constructed to harmonize. This means that it is necessary sometimes to provide for the imitation o f gold foils or three-quarter crowns when cutting out for the acrylic veneer. Esthetic results are in direct proportion to attention to details
MOULTON.*VOLUME52,JANUARY1956.43Fig.5.First row:Before and after treatment, utilizing acrylic open-face crown andSecond row:Utilization of three-pin hoods for replacinglong-pinporcelainfacing.lower anierior tooth. Third and fourth rows: Before and -after treatment eused incaseoftraumaticinjury
M O U LTO N . . . VO LUM E 52, JAN U A R Y 1956 • Fig. 5 • First row: Before and after treatment, utilizing acrylic open-face crown and long-pin porcelain facing. Second row: Utilization of three-pin hoods for replacing lower anterior tooth. Third and fourth rows: Before and after treatment used in case of traumatic injury
44THEJOURNALOFTHEAMERICAN DENTALASSOCIATIONtraindicated for several reasons, the mainLOWERANTERIORREPLACEMENTSonebeing discomfort.ThepatientThc lower anterior replacement is one ofstrenuously objected to even finger pres-the more difficult procedures. This issure on the ridge area.particularly true for the operator in theThe fixed replacement was the choiceearly years after graduation from dentalbut certain things had to be kept in mnind;school. The difficulties are partly respon-the construction of the pontics had to besible for the fact that many dentists avoidsuch that it would discourage what couldthe fixed prosthesis and fall back on thebe a disastrous tongue habit. The ponticshad to be lengthened so that the root tipsremovable replacement thatrequires nooperation on the natural dentition.rested on the ridge in normal anatomicIn a discussion of the lower anteriorrelationship. This would prevent thereplacement, it should be emphasizedtongue habit from loosening one or botheven more that the three-quarter crown isoftheretainers,orfrom creating excessiveseldom the retainer of choice. Heretrauma on the abutment teeth. Theagain, the contours of the teeth and thelength of the porcelain in such a casealignment of one abutment to anotherrequired adequate backing by gold castlend themselvesbettertothepreparationings on the lingual aspect to strengthenof other types of retainers. The three-pinthe porcelain facings. Thus a desirablehood can and should be used extensivelyrestoration was produced and a goodfor this replacement. The modified three-esthetic appearance created with the lipquarter crown is also valuable. And, ofin normal position.course, a type of full restoration, citherthe open-face type crown or the fullSUMMARY AND CONCLUSIONjacket, is needed to obtain an esthetic re-sult in those instances in which the teethTo meet the requirements of retentionhavebeen extensivelyrestored.Thereareand esthetics in an anterior fixed pros-manymodifications suitablefor use in thethesis, one must start with the selectionlower anterior replacements, so let it beof the retainer and preparation of theunderstood that when the three-quarterabutment. The three-quarter crown iscrown is termed inadequate, reference isthe retainer that answers perhaps themade to the standard type. Figure 5, sec-greatest need; because of variables inond row, shows a replacement that hasform, bulk and alignment, however, thebeen accomplished by the use of three-dentist must be able to modify thispin hood retainers. As shown here, thesepreparation. He therefore rnust learn toteeth lend themselves very well to theuse as basic preparations the modifiedthree-pin hood; also, there is adequatethree-quarter crown and the three-pinbulk for the pin type of retention.hood. It is in the preparation for theseMany times a dentist is called on toretainers that the dentist many timesconstruct a fixed prosthesis because of agoes amiss, and the result is actual over-traumatic injury. Traumatic injuries willreduction in one or more of the steps ofoften present unusual problems. An ex-the preparation which results in an un-ample is given in Figure 5, third andnecessary display of gold.fourth rows, which shows an instanceThe selection of the porcelain replace-where the lower four anterior teeth werement is of equal importance. It must filllost as the result of a gunshot woundthe space adeguately and harmonize induring the fighting in Korea. The man-size, contour and color. Many timesdible was fractured and, after healing,staining is necessary to produce this har-posed the problem of replacement. Themony of color.A type of full veneerremovable types of appliances were con-crown must be used in those instances
44 • THE JO U R N A L O F THE A M E R IC A N DENTAL AS S O C IA TIO N LOW ER ANTERIOR REPLACEMENTS T h e lower anterior replacement is one of the more difficult procedures. This is particularly true for the operator in the early years after graduation from dental school. T h e difficulties are partly responsible for the fact that many dentists avoid the fixed prosthesis and fall back on the removable replacement that requires no operation on the natural dentition. In a discussion of the lower anterior replacement, it should be emphasized even more that the three-quarter crown is seldom the retainer o f choice. Here again, the contours of the teeth and the alignment of one abutment to another lend themselves better to the preparation o f other types of retainers. T h e three-pin hood can and should be used extensively for this replacement. Th e modified threequarter crown is also valuable. And, of course, a type of full restoration, either the open-face type crown or the full jacket, is needed to obtain an esthetic result in those instances in which the teeth have been extensively restored. There are many modifications suitable for use in the lower anterior replacements, so let it be understood that when the three-quarter crown is termed inadequate, reference is made to the standard type. Figure 5, second row, shows a replacement that has been accomplished by the use of threepin hood retainers. As shown here, these teeth lend themselves very well to the three-pin hood; also, there is adequate bulk for the pin type o f retention. M any times a dentist is called on to construct a fixed prosthesis because o f a traumatic injury. Traum atic injuries w ill often present unusual problems. A n example is given in Figure 5, third and fourth rows, which shows an instance where the lower four anterior teeth were lost as the result of a gunshot wound during the fighting in Korea. T h e mandible was fractured and, after healing, posed the problem of replacement. Th e removable types o f appliances were contraindicated for several reasons, the main one being discomfort. T h e patient strenuously objected to even finger pressure on the ridge area. T h e fixed replacement was the choice, but certain things had to be kept in m ind; the construction o f the pontics had to be such that it would discourage what could be a disastrous tongue habit. T h e pontics had to be lengthened so that the root tips rested on the ridge in normal anatomic relationship. This would prevent the tongue habit from loosening one or both of the retainers, or from creating excessive trauma on the abutment teeth. The length o f the porcelain in such a case required adequate backing by gold castings on the lingual aspect- to strengthen the porcelain facings. Thus a desirable restoration was produced and a good esthetic appearance created with the lip in normal position. SUM M ARY AND CONCLUSION T o meet the requirements o f retention and esthetics in an anterior fixed prosthesis, one must start with the selection o f the retainer and preparation of the abutment. T h e three-quarter crown is the retainer that answers perhaps the greatest need; because o f variables in form, bulk and alignment, however, the dentist must be able to m odify this preparation. H e therefore must learn to use as basic preparations the modified three-quarter crown and the three-pin hood. It is in the preparation for these retainers that the dentist many times goes amiss, and the result is actual overreduction in one or more of the steps of the preparation which results in an unnecessary display of gold. T h e selection o f the porcelain replacement is o f equal importance. It must fill the space adequately and harmonize in size, contour and color. M any times staining is necessary to produce this harmony o f color. A type of full veneer crown must be used in those instances
SUMNICHT...VOLUME52,JANUARY195645where the esthetics of the individual toothby the reflection of light take on certaincharacteristics of form and color.has been lost because of fracture or ex-Various types of connectors are essen-tensive caries or restorations.tial to carry out the symmetry of theThe porcelain jacket is the restorationof choicewhenindicated.Occlusionwillmouth. To achieve ideal esthetic results,at times, contraindicate the use of athesoldered connector mustbe obscuredbrittle material such as porcelain. Atfrom the labial view, and proper refine-such times it is the open-face type ofment of the retainers prior to the takingcrown of either acrylic resin or porcelainof impressions for working models shouldthat should be utilized.accomplish this. Other than solderedThe success of the gold-acrylic resinconnectorsmustbeplanned for reproduccombination type retainer depends ontion of a diastema which is normal forthe attention given to many details havingan individual instance. It is apparent thatto do with color. In the main, these de-no one point is more important than an-tails concern the reproduction of contourother in the construction of the fixedand all minute labial markings whichbridge.produce highlights. Highlights produced323RobinhoodPlaceThe dentist's capabilities in the managementofmasscasualtiesRussell W.Sumnicht,D.D.S.,Washington,D.CMore than nine years has elapsed sincefense headed by Carl Sebelius of Nashthe first atomic bomb was dropped overville, Tenn., and other individuals andthe Japanese city of Hiroshima, yet thegroups of individuals in dentistry havemajority of experts still talk about whatmore than met their responsibilities inshould be done to meet atomic disaster,this regard, but for the most part, thebut say very little about what has beenroleof dentistryinatomicwarfaremustdone or what is being done at the presentbe discussed in the light of what shouldtime. Those who are charged with thebe done rather than what has been doneplanning have done an outstanding job.Before the dentist's capabilities in theWith a few exceptions,however, notmanagement of mass casualties can beenough individuals have been reachedevaluated,itisnecessarytoknowjustand persuaded to put an effective planwhat the need for the dentist will be. Ainto operation. Russell W. Bunting ofAnn Arbor, Mich., dental consultant toLieutenant,colonel,Dental,Corps,,Army Medicalthe Federal Civil Defense Administra-ServiceGraduateSchool,WalterReed ArmyMedication, members of the American DentalCenter.MemberAmericaDentalAssorlatiorCivil Defense of the Council on FederalAssociation Subcommittee on Civil De-DentalServices
S U M N IC H T . . . VO LU M E 52, JA N U A R Y 1956 • 45 where the esthetics of the individual tooth has been lost because o f fracture or extensive caries or restorations. Th e porcelain jacket is the restoration o f choice when indicated. Occlusion will, at times, contraindicate the use o f a brittle material such as porcelain. A t such times it is the open-face type of crown of either acrylic resin or porcelain that should be utilized. Th e success of the gold-acrylic resin combination type retainer depends on the attention given to many details having to do with color. In the main, these details concern the reproduction o f contour and all minute labial markings which produce highlights. Highlights produced by the reflection of light take on certain characteristics o f form and color. Various types o f connectors are essential to carry out the symmetry of the mouth. T o achieve ideal esthetic results, the soldered connector must be obscured from the labial view, and proper refinement o f the retainers prior to the taking of impressions for working models should accomplish this. O ther than soldered connectors must be planned fo r reproduction of a diastema which is normal for an individual instance. It is apparent that no one point is more important than another in the construction o f the fixed bridge. 323 R obinhood Place The dentist’s capabilities in the management of mass casualties Russell W . Sumnicht, D .D .S ., W ashington, D .C . M ore than nine years has elapsed since the first atomic bomb was dropped over the Japanese city of Hiroshima, yet the m ajority of experts still talk about what should be done to meet atomic disaster, but say very little about what has been done or what is being done at the present time. Those who are charged with the planning have done an outstanding job. W ith a few exceptions, however, not enough individuals have been reached and persuaded to put an effective plan into operation. Russell W . Bunting of Ann Arbor, M ich., dental consultant to the Federal Civil Defense Administration, members of the Am erican Dental Association Subcommittee on C ivil D efense headed by Carl Sebelius of Nashville, Tenn., and other individuals and groups o f individuals in dentistry have more than met their responsibilities in this regard, but fo r the most part, the role o f dentistry in atomic warfare must be discussed in the light of what should be done rather than what has been done. Before the dentist’s capabilities in the management o f mass casualties can be evaluated, it is necessary to know just what the need for the dentist will be. A Lieutenant colonel. Dental Corps, Arm y M edical Service G raduate School, W alter Reed Arm y M edical Center. M em ber, Am erican Dental Association Su b com mittee on C ivil Defense of the Council on Federal Dental Services