Radiographic identification of threaded endoseous dental implants

Transcription

1 Rdiogrphic identifiction of threded endoseous dentl implnts Indir G. Shiwl, BDS, DMD, MS, Ronld D. Woody, DDS, Byron W. Benson, DDS, MS, c nd Guillermo E. Guillen, DDS d Bylor College of Dentistry, Texs A&M University System, Dlls, Texs Sttement of prolem. The identifiction of dentl implnt odies in ptients without ville records is considerle prolem due to incresed ptient moility nd to the lrge numer of implnt systems with different designs. Purpose. The purpose of this study ws to document fetures tht would help dentists identify threded implnt odies from their rdiogrphic imges. Mteril nd methods. More thn 50 implnt mnufcturers were contcted nd sked to provide implnts with dimensions s close s possile to 3.75 mm (dimeter) 10 mm (length). Fortyfour implnts were donted, 28 of which were identified s threded. Rdiogrphs were mde of these implnts t 0, 30, 60, nd 90 horizontl rottion comined with 20, 10, 0, +10, nd +20 verticl inclintion reltive to the rdiogrphic em nd film. A totl of 20 imges per implnt were tken nd exmined to identify consistent, unique fetures tht would id in implnt identifiction. At 20 verticl inclintion, vitl fetures of implnts were distorted enough to e deemed unrecognizle. Therefore, only those oservtions mde from rdiogrphs etween 10 nd +10 verticl inclintion were used for implnt identifiction purposes. Results. All implnts could e recognized from rdiogrphs mde etween 10 nd +10 verticl inclintion. A series of tles nd flowchrts descrie the implnts ccording to their identifying fetures. Conclusion. Informtion from this study should help dentists identify threded endoseous implnts from their rdiogrphic imges. (J Prosthet Dent 2002;87: ) CLINICAL IMPLICATIONS Informtion from this study should help clinicins identify threded endoseous implnts from their rdiogrphic imges when no ptient records re ville. This cpility my increse the efficiency of restortion, id in emergency situtions, nd e useful in forensic identifiction. Vritions in rdiogrphic imges of implnt odies t different horizontl rottions nd verticl inclintions to the rdiogrphic em nd film cn e ttriuted to implnt design. 1-3 This vriility mens tht clinicin would hve to e fmilir with ll possile imges of n implnt efore he/she could use ny one rdiogrphic imge to identify it. The im of this investigtion ws to study multiple rdiogrphic imges of significnt numer of implnts nd document their identifying fetures. A flowchrt of these fetures would simplify the implnt identifiction process. Finncil support ws provided y Bylor College of Dentistry. Privte prctice, Plo Alto, Clif. Professor, Grdute Prosthodontics, Deprtment of Restortive Sciences. c Professor, Orl nd Mxillofcil Rdiology, Deprtment of Dignostic Sciences. d Associte Professor, Grdute Prosthodontics, Deprtment of Restortive Sciences. Fig. 1. Device used to conduct study. MAY 2002 THE JOURNAL OF PROSTHETIC DENTISTRY 563

2 THE JOURNAL OF PROSTHETIC DENTISTRY SAHIWAL ET AL Tle I. Implnts used in this study nd their mnufcturers Implnt nme Ace Screw Astr Fixture 4.0 Astr Fixture ST 4.5 Bicon Biohorizons 4 mm D1 Brånemrk SDCA 023 Brånemrk MkII SDCA 220 Brånemrk MkIll Fritec-2 stepped screw Imtec ITI Solid Screw S LminOss Minimtic IHPSS410 O Compny 4010 Osteoimplnt Prgon Micro-Vent MTH10 Prgon Complete Screw-Vent CSVB10 (01129) Prc Strlock Str V003 Prc Strvent Str V044 Replce Restore R Srgon Spline 1980 Sterioss 2210 Sterngold Implmed Sustin i Osteotite OSS 410 3i TG 2410 Implnt mnufcturer Ace Dentl Implnt System, Brockton, Mss. Astr Tech Inc, Lexington, Mss. Astr Tech Inc Bicon Dentl Implnts, Boston, Mss. Biohorizons Implnt System Inc, Birminghm, Al. Noelphrm AB, Goteerg, Sweden Noelphrm AB Noelphrm AB Frident, Irvine, Clif. Imtec Corportion, Ardmore, Okl. Institut Strumnn AG, Wldenurg, Switzerlnd Impldent Ltd, Holliswood, N.Y. Minimtic Implnt Technology, Boc Rton, Fl. O Compny Inc, Aluquerque, N.M. Osteo-Implnt Corportion, New Cstle, P. Prgon Implnt Compny, Encino, Clif. Prgon Implnt Compny Prk Dentl Reserch Corp, New York, N.Y. Prk Dentl Reserch Corp Sterioss Dentl Implnts, Yor Lind, Clif. Lifecore Biomedicl Inc, Chsk, Minn. Srgon Dentl Implnts, Beverly Hills, Clif. Sulzer Clcitek, Crlsd, Clif. Sterioss Dentl Implnts Sterngold Implmed Dentl Implnt Systems, Attleoro, Mss. Lifecore Biomedicl Inc Implnt Innovtions Inc, Plm Bech Grdens, Fl. Implnt Innovtions MATERIAL AND METHODS Letters were sent to more thn 50 implnt mnufcturers requesting implnts with dimensions s close s possile to 3.75 mm (dimeter) 10 mm (length). Forty-four implnts were donted, 28 of which were identified s threded (Tle I). The morphologicl design chrcteristics of ll 44 implnts were descried in previous rticle. 4 A specil device (Fig. 1) ws fricted to mke stndrdized rdiogrphs of the 28 threded implnts t different horizontl rottions nd verticl inclintions. The implnts were mounted on resin cylinder 4 cm long nd 1.5 cm wide with dimple on one end to hold the implnt nd cylindricl opening in the middle of the rod t the other end. The implnt ws mounted in the dimple on the resin rod with glue gun, nd surveyor ws used to confirm tht the implnt ws perpendiculr to the se. Distinctive fetures of the implnt, such s picl holes, were plced perpendiculr to the rdiogrphic em s seline. The resin rod ws mounted in the center of circulr tle 4 cm wide, such tht the opening t the opposite end of the resin rod fit on nrrow rod (0.5 cm wide nd 1 cm long) tht extended from the center of the tle. This ws done in such mnner tht the resin rod could e rotted 360 on the tle rod. The tle ws mrked every 30. The resin rod hd verticl mrk on its side so tht its rottion reltive to the tle could e documented. This tle ws further mounted such tht the whole pprtus could e inclined through 40 ( 20 to +20 ) in the verticl plne. An iming ring from rdiogrphic film holding system (XCP; Dentsply-Rinn, Elgin, Ill.) ws mounted 5 cm from the center of the cler rod, nd the film-holding instrument ws mounted 4.5 cm from the center of the rod on se. The focl spot to oject distnce ws 25 cm, nd the focl spot to film distnce ws 29.5 cm. The film nd tue were lwys prllel to ech other, nd only the inclintion of the implnt chnged. The entire setup ws designed to mimic clinicl situtions in which the opertor is not fmilir with the inclintion of the implnt ut hs control over film nd tue position. Optiml rdiogrphic exposure fctors were determined sujectively y imging n extrcted premolr. A premolr ws chosen ecuse its size is etween tht of n incisor nd molr. The tooth ws plced on the rod, nd rdiogrphs were mde t 0.16, 0.20, 0.25, 564 VOLUME 87 NUMBER 5

3 SAHIWAL ET AL THE JOURNAL OF PROSTHETIC DENTISTRY Tle II. Rdiogrphic fetures of the coronl prt of the implnts ( 20 to +20 ) Implnt Implnt Externl Internl Morse Wider Stright Flred Unique numer nme hex hex tper Other flnge flnge flnge feture 1 Fritec-2 stepped screw Prgon Micro-Vent MTH Replce Restore R Ace Screw Astr Fixture Astr Fixture ST Fine threds on entire flnge 8 Bicon 0-2 No flnge 9 Biohorizons 4 mm D Brånemrk SDCA Brånemrk MkII SDCA Brånemrk MkIll Imtec ITI Solid Screw S LminOss 0-2 Ellipticl flnge 16 Minimtic IHPSS O Compny Osteoimplnt Prgon Complete Screw Vent CSVB10 (01129) 20 Prc Strlock Str V Prc Strvent Str V Srgon Spline Sterioss Sterngold Implmed Sustin i Osteotite OSS i TG Apicl prt of flre grooved nd 0.32 seconds. An exposure time of 0.20 seconds, kvp of 63, nd n ma of 8 were chosen sujectively to simulte clinicl sitution. All rdiogrphs were mde t these exposures. Ultr speed rdiogrphic film (D speed; Estmn Kodk, Rochester, N.Y.) ws used in stndrd rdiogrphic unit (Prostyle; Prostyle Intr, Plnmecc USA Inc, Woodle, Ill.) nd processed in n utomted mchine (AT2000; Air Techniques Inc, Hicksville, N.Y.). Rdiogrphs for ech implnt were numered 1 through 20. All rdiogrphs were mde in the sme sequence, strting t 0 horizontl rottion nd 20 (20 towrd the cone) verticl inclintion. The verticl inclintion ws chnged to 10, 0, +10, nd +20 while the horizontl rottion remined constnt. At 0 verticl inclintion, the rdiogrphic em ws perpendiculr to oth the implnt nd the film. The horizontl rottion ws then chnged to 30, 60, nd 90 ; t ech MAY

4 THE JOURNAL OF PROSTHETIC DENTISTRY SAHIWAL ET AL Tle III. Rdiogrphic fetures of the midody of the implnts ( 20 to +20 ) Reverse Implnt Implnt Non- Non- V-shped Squre uttress Unique numer nme Tpered tpered Threded threded threds threds threds feture 1 Fritec-2 stepped screw Stepped 2 Prgon Micro-Vent MTH types of threds (v t pex) 3 Replce Very thin threds 4 Restore R Ace Screw Astr Fixture Astr Fixture ST Bicon Fish skeleton like ody 9 Biohorizons 4 mm D Brånemrk SDCA Brånemrk MkII SDCA Brånemrk MkIll Imtec ITI Solid Screw S LminOss Very wide threds 16 Minimtic IHPSS O Compny Osteoimplnt Prgon Complete Screw Vent CSVB10 (01129) 20 Prc Strlock Str V Prc Strvent Str V Srgon Expnding screw in middle 23 Spline Sterioss Very thin threds 25 Sterngold Implmed Sustin Threds on coronl hlf of ody 27 3i Osteotite OSS i TG stop, the verticl inclintion ws put into the sme series of ngles descried ove (from 20 to +20 ). Before the rdiogrphs were mde, mounting sheets were prepred for ll implnts. Ech sheet ws leled with the nme of the implnt, nd ech pocket ws numered to coincide with the numer of the film. Upon completion of series of rdiogrphs ut prior to their eing developed, the sequence of the numers ws verified. The mounting sheet ws tken into the drk room, nd films were mounted into the corresponding pocket s they cme out of the developer to eliminte the possiility of misleling or misidentifying rdiogrphs. Films were red on lighted ox with viewscope (Person Dentl Supply Compny, Sylmr, Clif.) t 2 mgnifiction; extrneous light ws locked out. 566 VOLUME 87 NUMBER 5

5 SAHIWAL ET AL THE JOURNAL OF PROSTHETIC DENTISTRY Tle IV. Rdiogrphic fetures of the picl prt of the implnts ( 20 to +20 ) Implnt Implnt V-shped Flt Curved Round Olong Apicl Unique numer nme pex pex pex hole hole chmer Grooves feture 1 Fritec-2 stepped screw Prgon Micro-Vent MTH Replce Restore R Ace Screw Astr Fixture Astr Fixture ST Bicon Biohorizons 4 mm D Brånemrk SDCA Brånemrk MkII SDCA Apicl prt hs curved indent 12 Brånemrk MkIll Apicl prt hs curved indent 13 Imtec ITI Solid Screw S LminOss Minimtic IHPSS O Compny Osteoimplnt Prgon Complete Screw Vent CSVB10 (01129) 20 Prc Strlock Str V Prc Strvent Str V Srgon Split, flred pex with expnding screw in middle 23 Spline Stright cut on one side 24 Sterioss Sterngold Implmed Sustin i Osteotite OSS Grooves crete tpered look 28 3i TG Oservtions were recorded on 4 dt collection sheets, 1 ech for coronl, midody, pex, nd screw chmer fetures. On ech form, the 20 ngle comintions were listed verticlly nd the chosen fetures horizontlly. A check mrk ws plced in the proper ox when certin feture ws present t certin ngle. The rdiogrphs were lso nlyzed with n ritrry, sujective, nonprmetric scle of 0 to 3. The seline ws 0 nd included fetures t the 0, 0 ngle (0 horizontl rottion with the em directed perpendiculr to the implnt). An imge t different ngle tht showed no chnge from the se- MAY

6 THE JOURNAL OF PROSTHETIC DENTISTRY SAHIWAL ET AL Tle V. Rdiogrphic fetures of the screw chmer of the implnts ( 20 to +20 ) Implnt Implnt Non- Curved Flt V-shped Unique numer nme Stright Stepped Threded threded end end end feture 1 Fritec-2 stepped screw 0-2 Screw chmer indistinct 2 Prgon Micro-Vent MTH Replce Restore R Ace Screw Astr Fixture Astr Fixture ST Bicon No screw chmer 9 Biohorizons 4 mm D Screw chmer 3 /4 length of ody 10 Brånemrk SDCA Brånemrk MkII SDCA Brånemrk MkIll Imtec ITI Solid Screw S LminOss No screw chmer 16 Minimtic IHPSS O Compny Osteoimplnt Prgon Complete Screw- 0-2 Ends in flnge Vent CSVB10 (01129) 20 Prc Strlock Str V Prc Strvent Str V044 Ends in flnge 22 Srgon 0-3 Hs no ottom, just expnding screw 23 Spline Sterioss Ends t 2nd or 3rd thred 25 Sterngold Implmed Sustin i Osteotite OSS i TG line ws lso leled 0. An imge ws leled 1 when only slight vrition from the seline ws oserved with ll seline fetures visile ut no dditionl fetures present; 2 when lrge vrition from the seline ws oserved with ll seline fetures visile ut no dditionl fetures present; nd 3 when some seline fetures were sent or dditionl fetures were present, thus chnging the imge. This methodology mde it esy to oserve vrition t different ngles from the tle nd llowed ech implnt to ct s its own control (imge t 0,0 ). The principl investigtor mde, processed, nd mounted ll rdiogrphs nd then compiled ll dt under the guidnce of mentors. RESULTS Dt were compiled for inclintions from 20 to +20 (Tles II through V) nd for inclintions from 568 VOLUME 87 NUMBER 5

7 SAHIWAL ET AL THE JOURNAL OF PROSTHETIC DENTISTRY Tle VI. Rdiogrphic fetures of the coronl prt of the implnts ( 10 to +10 ) Implnt Implnt Externl Internl Morse Wider Stright Flred Unique numer nme hex hex tper Other flnge flnge flnge feture 1 Fritec-2 stepped screw Prgon Micro-Vent MTH Replce Restore R Ace Screw Astr Fixture Astr Fixture ST Fine threds on entire flnge 8 Bicon 0-1 No flnge 9 Biohorizons 4 mm D Brånemrk SDCA Brånemrk MkII SDCA Brånemrk MkIll Imtec ITI Solid Screw S LminOss 0-1 Ellipticl flnge 16 Minimtic IHPSS O Compny Osteoimplnt Prgon Complete Screw-Vent CSVB10 (01129) 20 Prc Strlock Str V Prc Strvent Str V Srgon Spline Sterioss Sterngold Implmed Sustin i Osteotite OSS i TG Apicl prt of flre grooved 10 to +10 (Tles VI-IX). The presence of selected fetures ws noted long with the rnge of vrition for ech feture t different ngles. The prosthetic interfce ws descried in the dt forms for completion of description. It ws not, however, included in implnt identifiction ecuse in norml clinicl conditions it is covered with either the heling cp or the utment nd thus not visile. Similrly, the shpe of the end of the screw chmer, though descried, could e used for identifiction only rrely due to the extreme sutlety of this feture. In nonthreded implnts, the spirl imge round the screw chmer lwys indictes tht it is threded. The sme cnnot e ssumed for threded implnts, s this spirl imge could e the superimposition of the threds of the ody. In this study, the screw chmer ws considered threded only when MAY

8 THE JOURNAL OF PROSTHETIC DENTISTRY SAHIWAL ET AL Tle VII. Rdiogrphic fetures of the midody of the implnts ( 10 to +10 ) Reverse Implnt Implnt Non- Non- V-shped Squre uttress Unique numer nme Tpered tpered Threded threded threds threds threds feture 1 Fritec-2 stepped screw Stepped 2 Prgon Micro-Vent MTH types of threds (v t pex) 3 Replce Very thin threds 4 Restore R Ace Screw Astr Fixture Astr Fixture ST Bicon Fish skeleton like ody 9 Biohorizons 4 mm D Brånemrk SDCA Brånemrk MkII SDCA Brånemrk MkIll Imtec ITI Solid Screw S LminOss Very wide threds 16 Minimtic IHPSS O Compny Osteoimplnt Prgon Complete Screw Vent CSVB10 (01129) 20 Prc Strlock Str V Prc Strvent Str V Srgon Expnding screw in middle 23 Spline Sterioss Very thin threds 25 Sterngold Implmed Sustin Threds on coronl hlf of ody 27 3i Osteotite OSS i TG the teeth of the threds were visile in the rdiogrphic imge. Results were estlished for threded, tpered implnts (Fig. 2, A) nd threded, nontpered implnts (Fig. 2, B). Becuse the numer of implnts in the threded, nontpered ctegory ws lrge, their fetures re presented seprtely in Tle X. The identifying fetures were present t ll inclintions ( 10 to +10 ); the other fetures were not pprent t ll inclintions. DISCUSSION In reference to Tle X, it is importnt to rememer tht implnts with identifying fetures would hve to e eliminted from group or sugroup efore implnts without identifying fetures could e identified. As n exmple, consider the implnts tht re threded, re nontpered, nd hve v-shped threds nd wider flnges. Of the 7 implnts in this group, 5 hve identifying fetures. If these 5 were eliminted, informtion in the other fetures column could e used to distinguish 570 VOLUME 87 NUMBER 5

9 SAHIWAL ET AL THE JOURNAL OF PROSTHETIC DENTISTRY A B Fig. 2. A, Flowchrt for identifiction of threded, tpered implnts. Numer ssigned to implnt in prentheses. B, Flowchrt for identifiction of threded, nontpered implnts. Numer ssigned to implnt in prentheses. etween the remining 2 implnts, only 1 of which hs n picl chmer. If the implnts with distinguishing fetures hd not een eliminted, more implnts in the group would hve n picl chmer, mking identifiction sed on this feture lone difficult. A few implnts in this study were identified esily y their distinctive designs. Little vriility ws evident in the rdiogrphic imges of the Bicon, LminOss, nd Srgon implnts, for exmple, regrdless of the verticl inclintion in reltion to the rdiogrphic MAY

10 THE JOURNAL OF PROSTHETIC DENTISTRY SAHIWAL ET AL Fig. 3. () Bicon implnt, () LminOss implnt, nd (c) Srgon implnt. Fig. 4. ITI Solid Screw S t () 0, 0 ; () 30, 0 ; nd (c) 0, 10. em nd film (Fig. 3). The identifiction of most other implnts ws chllenging ecuse of similrities in their designs nd the production of different imges with chnges in rottion nd verticl inclintion. These differences cn e ttriuted to chnge in the reltionship of the picl fetures of the implnts to the rdiogrphic em nd film. The ITI solid screw , which hs no picl fetures, exhiited miniml chnge with horizontl rottion nd only slight chnge in thred morphology with vritions in verticl inclintion (Fig. 4). As such, the ITI solid screw ws redily identifile. The Sterngold Implmed is n excellent exmple of how picl fetures cn complicte implnt identifiction. This implnt hs 2 round holes, n picl chmer, nd 4 grooves in the picl re. These fetures crete vriety of imges depending on the rottion of the implnt, even when the verticl inclintion remins unchnged (Fig. 5). If the hole fces the rdiogrphic em nd is perpendiculr to it (verticl inclintion 0 ), the em psses directly through the 2 holes 180 prt. The implnt ppers cylindri- c c cl with rdiolucent circle nd reltively rdiolucent chmer elow it. At 30 horizontl rottion, 2 overlpping, reltively rdiolucent circles nd reltively rdiolucent chmer elow them cn e seen; t 60, the 2 reltive rdiolucencies in the picl re re still visile ut the chmer is not. At 90, the implnt ppers slightly tpered in the picl re with 2 reltive semicirculr rdiolucencies t the edges nd very cler imge of the chmer s reltive rdiolucency. Although the picl prt of the rdiogrphic imges oviously cnnot e used to identify the Sterngold Implmed , the implnt is nonetheless redily identifile. It elongs to sugroup of 4 implnts (Fig. 2, B), nd within this sugroup (Tle X), only 2 implnts hve flnges 1 mm long: the Sterngold Implmed nd the Osteoimplnt The ltter hs screw chmer with ul-like end. If this chmer is not present, then the implnt must e the Sterngold Implmed A tper on the Sterngold Implmed ppers when 2 grooves re prllel to the film. If this imge were the only one ville, clinicin unfmilir with the criteri used to plce implnts in certin ctegories might e tempted to plce this implnt in the tpered group. As noted in previous rticle, 4 it is criticl tht only the middle third of n implnt e used to identify it s tpered or nontpered. Implnt identifiction cn then proceed sed on Figure 2. The fetures of some dentl implnts re very sutle nd require close exmintion. The tper of the Replce 43101, for exmple, is grdul nd not s ovious s tht of the Prgon Micro-Vent MTH10 (Fig. 6). Similrly, the threds of the Minimtic IHPSS410, Sterioss 2210, nd Replce re ll clssified s reverse uttress, ut the threds of the Minimtic implnt re much corser thn those of the other two (Fig. 7). The threds of the Minimtic implnt re lso directed piclly, creting Christms tree like imge, wheres the threds of the Sterioss nd Replce implnts re directed upwrd nd therey reverse the imge. The Sterngold Implmed nd Astr Fixture 4.0 threded implnts hve flnges tht my pper wider ut re ctully stright (Fig. 8). Under mgnifiction, it ecomes ovious tht the ends of the threds nd flnge line up. Considerle distortion of the picl fetures nd thred shpes t verticl inclintions greter thn 10 ws oserved in this study. Circulr holes t the pex ppered olong, for exmple, nd determining thred shpe ecme incresingly difficult t incresed verticl inclintions. Such prolems could led to flse identifiction. Given this possiility, the clinicin should pproximte the ngle t which rdiogrph ws mde efore using it for implnt identifiction. The oservtion of predictle chnges in imges of the threds, 572 VOLUME 87 NUMBER 5

11 SAHIWAL ET AL THE JOURNAL OF PROSTHETIC DENTISTRY c d Fig. 5. Sterngold Implmed t () 0, 0 ; () 30, 0 ; (c) 60, 0 ; nd (d) 90, 0. c Fig. 7. Reverse uttress threds in () Minimtic IHPSS410, () Sterioss 2210, nd (c) Replce Fig. 6. () Tpered Replce nd () Tpered Prgon Micro-Vent MTH10. picl chmer, nd internl prosthetic interfces of the implnt enles pproximtion of the verticl inclintion of implnts reltive to the em nd film. With threded implnts, the rdiogrphic ppernce of the threds cn e used to determine the verticl inclintion of the implnt reltive to the film nd em (Fig. 4). Sewerin 5 investigted this possiility with imges of Brånemrk implnt threds nd found tht 81% of recordings estimted y clinicins differed y 2 when the clinicins were provided with set of reference rdiogrphs. The picl chmer lso cn e used to estimte the verticl inclintion of n implnt to the em nd film. When present nd not covered y nother feture, the picl chmer of n implnt usully ppers s reltive rdiolucency in the picl re t 0 verticl ngultion. Regrdless of whether the picl chmer cn e seen t 0, the circumference of the chmer ecomes incresingly visile t the pex t incresed verticl ngultions ecuse the 2 sides of the implnt do not overlp (Fig. 9). A visile circumference of the picl chmer therefore indictes tht the rdiogrphic em is not t right ngle to the xis of the implnt in tht prticulr rdiogrph. This would lso e true if the implnt were not prllel to the film. The degree Fig. 8. Stright flnge in () Sterngold Implmed nd () Astr Fixture 4.0. to which the picl chmer circumference is visile should give n stute clinicin n pproximte ide of the implnt inclintion to the film nd em. This informtion could lso help in implnt identifiction when the presence of n picl chmer is suspected, s chnging the em ngultion might help clrify the picl chmer nd thus identify the implnt. The internl hex (or ny other internl prosthetic interfce, if present nd visile) lso ecomes incresingly identifile t incresed verticl ngles (Fig. 10). Studies hve demonstrted tht the ccurcy of one height mesurements is compromised even t MAY

12 THE JOURNAL OF PROSTHETIC DENTISTRY SAHIWAL ET AL Tle VIII. Rdiogrphic fetures of the picl prt of the implnts ( 10 to +10 ) Implnt Implnt V-shped Flt Curved Round Olong Apicl Unique numer nme pex pex pex hole hole chmer Grooves feture 1 Fritec-2 stepped screw Prgon Micro-Vent MTH Replce Restore R Ace Screw Astr Fixture Astr Fixture ST Bicon Biohorizons 4 mm D Brånemrk SDCA Brånemrk MkII SDCA Apicl prt hs curved indent 12 Brånemrk MkIll Apicl prt hs curved indent 13 Imtec ITI Solid Screw S LminOss Minimtic IHPSS O Compny Osteoimplnt Prgon Complete Screw Vent CSVB10 (01129) 20 Prc Strlock Str V Prc Strvent Str V Srgon Split, flred pex with expnding screw in middle 23 Spline Stright cut on one side 24 Sterioss Sterngold Implmed Sustin i Osteotite OSS Grooves crete tpered look 28 3i TG very smll devitions from prllelism etween the implnt ody xis nd film plne. 6,7 This discrepncy is further incresed with greter width of the lveolr process. Bsed on theoreticl nd experimentl model, it ws reported tht distortion etween one mrgins vried etween 0.1 mm t 1 verticl ngultion nd 4.8 mm t 20 verticl ngultion depending on the width of the lveolr ridge nd uccolingul position of the implnt ody. It ws lso reported tht ignoring differences in projection ngles my led to 574 VOLUME 87 NUMBER 5

13 SAHIWAL ET AL THE JOURNAL OF PROSTHETIC DENTISTRY Tle IX. Rdiogrphic fetures of the screw chmer of the implnts ( 10 to +10 ) Implnt Implnt Non- Curved Flt V-shped Unique numer nme Stright Stepped Threded threded end end end feture 1 Fritec-2 stepped screw 0-1 Screw chmer indistinct 2 Prgon Micro-Vent MTH Replce Restore R Ace Screw Astr Fixture Astr Fixture ST Bicon No screw chmer 9 Biohorizons 4 mm D Screw chmer 3 /4 length of ody 10 Brånemrk SDCA Brånemrk MkII SDCA Brånemrk MkIll Imtec ITI Solid Screw S Lminoss No screw chmer 16 Minimtic IHPSS O Compny Osteoimplnt Prgon Complete Screw-Vent 0-1 Ends in flnge CSVB10 (01129) 20 Prc Strlock Str V Prc Strvent Str V044 Ends in flnge 22 Srgon 0-3 Hs no ottom, just expnding screw 23 Spline Sterioss Ends t 2nd or 3rd thred 25 Sterngold Implmed Sustin i Osteotite OSS i TG flse impression of one growth or to n underestimtion of one loss round implnts. If n implnt is depicted from n olique view, the one djcent to the fixture will pper more condensed thn it would if the projection ngle were 90. The fct tht chnging the ngle of the rdiogrphic em cn result in different imges of the sme clinicl sitution underscores the importnce of eing le to estimte ngultion sed on the visiility of certin implnt fetures. Another importnt clinicl ppliction of this skill is confirmtion of implnt-utment nd utmentprosthesis seting. Ormeche et l 8 reported tht 5 verticl ngle of the x-ry tue to the implnt xis did not significntly ffect the identifiction of openings 50 µm. A 15 verticl ngultion of the x-ry tue, MAY

14 THE JOURNAL OF PROSTHETIC DENTISTRY SAHIWAL ET AL Tle X. Fetures of implnts ctegorized in Figure 2, B Implnt nme Identifying fetures Other fetures V-shped threds, wider flnge Brnemrk Apicl chmer, round hole Brånemrk MkII Semicirculr cut lterlly t picl end Brånemrk Mk III Semicirculr cut lterlly t picl end Imtec Flnge 2 mm Olong hole Prgon Screw-Vent Long flnge, stright nd then wider Olong hole Spline Stright cut lterlly t picl end 3i Osteotite No picl chmer, round hole V-shped threds, flred flnge, flt end to screw chmer Astr 4.5 Fine threds on entire flnge Flnge lmost 1 2 ody length V-shped threds, flred flnge, curved end to screw chmer 3i TG Grooves on picl hlf of flnge only V-shped threds, stright flnge, flt pex Ace No Morse tper, flnge 2 mm Olong hole, picl chmer Astr Morse tper, flnge 2 mm No hole or picl chmer Sterngold Implmed Flnge 1 mm Round hole, picl chmer Osteoimplnt Screw chmer ul-like end, flnge 1 mm Round hole, picl chmer V-shped threds, stright flnge, curved pex O Compny Squre threds Biohorizons Sustin Flnge 2 mm Screw chmer 3 4 ody length nd stepped Threds in only coronl prt of implnt Reverse uttress threds, flred flnge ITI Solid Screw Morse tper Screw chmer extends into ody Prc Strvent Screw chmer in flnge No Morse tper Reverse uttress threds, wider flnge, flt pex Minimtic Screw chmer 1 2 ody length, corse threds, Apicl chmer flnge 1 mm Sterioss Screw chmer 1 3 ody length, very fine threds, flnge 2 mm Reverse uttress threds, wider flnge, curved pex Prc Strlock Stepped screw chmer however, significntly ffected the identifiction of 100 to 150 µm openings. Fmilirity with imges of the picl chmer nd threds t vrious degrees of ngultion could help the clinicin recognize rdiogrphs with >10 ngultion nd so void misestimting utment or prosthesis seting. The only implnts tht could not e distinguished from ech other were the Brånemrk MkII nd MkIII. This is not n issue ecuse the restortive components of these 2 implnts re common. Appliction of the in vitro dt gthered in this study my e limited y possile vritions in film density, film processing, projection ngultions, nd implnt rottions in the clinicl setting. Due to resource, spce, nd time limittions, ll implnt systems on the mrket could not e included in this study. The inclusion or exclusion of ny prticulr system is not ment to infer its superiority or inferiority. CONCLUSIONS The dt gthered in this study should mke the identifiction of unknown threded implnts esier for the clinicin. The ility to estimte rdiogrph ngultion my improve clinicl judgment out the comprility of rdiogrphs t recll nd help confirm utment nd/or prosthesis seting. The dontion of ll implnts y their respective mnufcturers is cknowledged nd pprecited. REFERENCES 1. Sewerin I. Identifiction of dentl implnts on rdiogrphs. Quintessence Int 1992;23: VOLUME 87 NUMBER 5

15 SAHIWAL ET AL THE JOURNAL OF PROSTHETIC DENTISTRY Fig. 9. Apicl chmer in Restore R t () 0, 0 nd () 0, Sewerin I. Rdiogrphic imge chrcteristics of Brånemrk titnium fixtures. Swed Dent J 1992;16: Sewerin IP. Comprison of rdiogrphic imge chrcteristics of Brånemrk nd IMZ implnts. Clin Orl Implnts Res 1991;2: Shiwl IG, Woody RD, Benson BW, Guillen GE. Mcro design morphology of endoseous dentl implnts. J Prosthet Dent 2002;87: Sewerin IP. Estimtion of ngultion of Brånemrk titnium fixtures from rdiogrphic thred imges. Clin Orl Implnts Res 1991;2: Sewerin IP. Errors in rdiogrphic ssessment of mrginl one height round osseointegrted implnts. Scnd J Dent Res 1990;98: Hollender L, Rockler B. Rdiogrphic evlution of osseointegrted implnts of the jws. Experimentl study of the influence of rdiogrphic techniques on the mesurement of the reltion etween the implnt nd one. Dentomxillofc Rdiol 1980;9: Begon Ormeche M, Millstein P, Hirym H. Tue ngultion effect on rdiogrphic nlysis of the implnt-utment interfce. Int J Orl Mxillofc Implnts 1999;14: Fig. 10. Internl hex in Prgon Micro-Vent MTH10 t () 90, 0 nd () 90, 10. Reprint requests to: DR INDIRA G. SAHIWAL 15, CRYSTAL SPRINGS TERRACE HILLSBOROUGH, CA FAX: (650) ishiwl@yhoo.com Copyright 2002 y The Editoril Council of The Journl of Prosthetic Dentistry /2002/$ /1/ doi: /mpr MAY