Volume 27Number 5

October 2007

Special reprint from

Copyright © 2007 by Quintessence Publ Co, Inc

6. Impressions were made, study castscreated, and a surgical guide fabri-cated on an ideal waxup.

Implant placement

1. In all cases, facial and lingual infil-tration utilizing lidocaine with epi-nephrine 1:100,000 were used toobtain local anesthesia. In patientsunable to tolerate this anesthetic,carbocaine 3% without epinephrinewas used.

2. A crestal incision was made, and alimited soft tissue flap was reflectedto expose the crest of bone.

3. With a 1.3-mm twist drill with 7-, 10-, and 14-mm laser markings (cor-responding to the size of theimplants), osteotomies were drilledat 1,500 revolutions per minute usingconstant copious irrigation (Fig 1d).In areas of dense cortical bone(mandibular anterior area), the drillwas inserted two or three times tothe desired depth to allow stress-free placement of the implants.

3. The proper mold and shade of poly-carbonate crown was selected, orlaboratory fabrication of a hollowcrown from an ideal waxup was per-formed, in advance of the clinicalprocedure.

4. The provisional restoration was fab-ricated using the polycarbonatecrown, laboratory-prefabricated hol-low crown, or a vacuum-formedshell filled with quick-curing acrylicresin (Jet, Lang Dental). The provi-sional was trimmed and polished.The screw cap was disassembled bycounterclockwise rotation with thesquare driver.

5. The provisional restoration wasplaced over the abutment and theocclusion adjusted so as to avoidcontact in centric and excursivemovements. The crown wasreassembled with the screw cap.The screw opening was temporarilyfilled with visible off-color tempo-rary acrylic resin for future access.

4. With the handpiece adapter or man-ual driver included in the surgicalkit, the implants were placed to thedesired depth at 30 revolutions perminute. A manual tactile driver wasused to achieve the final insertiondepth. This hand tapping was per-formed to maximize initial stability ofthe implant.

Fabrication of the provisional

1. The titanium indexing abutment wasplaced over the implant squarehead in contact with the 3.2-mmimplant platform. (This coping maybe placed in a buccolingual ormesiodistal direction.)

2. A nonhygroscopic acrylic resin screwcap was inserted over the implanthead, locking the index copingfirmly in place with the manualsquare driver (Fig 1e). The open endof the screw cap was plugged witha brass insert to prevent the acrylicresin from blocking its access.

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Fig 1d (left) View of the 1.3-mm twist drillpreparing the osteotomy for implant place-ment.

Fig 1e (right) The indexing abutment andnonhygroscopic screw cap attached to theabutment head.

6. The soft tissue flap was repositionedand sutured with absorbable inter-rupted 4-0 chromic gut sutures toobtain interproximal closure (Fig 1f).

All patients were placed on antibi-otic coverage (amoxicillin 2,000 mg 1hour prior to surgery, followed by 250mg four times a day for 7 days follow-ing surgery; patients unable to takeamoxicillin received clindamycin 600mg 1 hour prior to surgery, followed byclindamycin 150 mg four times a dayfor 7 days). Patients were placed on1.2% chlorhexidine rinse (Peridex, ZilaTechnical) twice a day for 3 weeks start-ing 2 days prior to surgery. Patientswere instructed to avoid hard contactwith the implant restoration for 3 to 4months following surgery. Patientswere also advised to lightly brush andgently floss the surgical area starting 3

weeks after surgery. Patients returnedevery 2 weeks for 2 months aftersurgery and once a month thereafterfor 2 to 4 months for maintenance andmonitoring of the area.

Approximately 4 months afterimplant placement in the mandibleand 6 months after placement in themaxilla, the screw-retained provision-als were replaced with a metal-ceramicor acrylic resin crown using conven-tional impression analog transfer tech-niques for models and laboratory-con-structed restorations.

Fabrication of the definitiverestoration

1. The indexed impression coping wasattached with the gray technicalscrew cap to the implant.

2. A closed-tray impression was madeof the screw-attached index copingusing elastomeric impression mate-rial (Reprosil Vinyl Polysiloxane Im-pression Material, Dentsply/Caulk);this was used for making an indexedmaster cast.

3. The transfer coping was attached tothe analog and re-inserted into theimpression with an implant analog.

4. The master cast was made with asoft tissue base for the constructionof the restoration.

5. The definitive restoration was thenfabricated using gold or plastic copings.

6. A porcelain-fused-to-metal crownwas fabricated using conventionalclinical and technical laboratory pro-cedures (Figs 1g to 1i).

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Fig 1f (left) Following placement of theacrylic resin crown, the flap is sutured with4-0 absorbable chromic gut.

Fig 1g (right) (left) Radiograph of the NDIand indexing abutment. (right) Radiographof implant and definitive restoration 5 yearsafter surgery.

Fig 1h (left) Clinical view of the definitiveimplant-supported porcelain crown.

Fig 1i (right) Facial view of the definitivelateral incisor implant restoration.

Results

In this study, 27 patients received 48NDIs, which were loaded for periods of12 to 64 months postinsertion. To date,no implant or prosthesis has had to beremoved or replaced. Two screw-retained crowns loosened; the com-posite was removed and the screw capwas tightened without patient dis-comfort or interruption of the functionof the implant restoration. Each patienthas been recalled at 2- to 3-monthintervals for maintenance and reex-amination.

Discussion

Re-formation of the horizontal widtharound an implant requires a minimumdistance of 1.5 mm between theimplant surface and the neighboringtooth to allow maintenance of ade-quate interproximal bone. Standard-diameter implants of 4.0 mm orgreater, therefore, require a mesial-to-distal edentulous distance of at least 7mm between two teeth to place animplant and maintain the properrestorative distances. Moreover, stan-dard-diameter implants require at least2 mm of bone buccal to the implant toavoid bone resorption and gingivalshrinkage, which then requires agreater apicocoronal dimension of thecrown restoration. Restoration of theimplant in such cases requires an arti-ficially long implant crown, resulting incompromised esthetics.

Ridge augmentation proceduresare often required to create adequatebuccolingual bone to maintain a 2-mm bone thickness following implant

placement. NDIs (1.8, 2.2, and 2.4 mm)present a solution for the aforemen-tioned requirements of adequate buc-colingual bone dimensions and properimplant spacing without the need forridge augmentation. Because of theirsmaller diameters, NDIs also result ina greater thickness of remaining buc-cal bone following the osteotomies forimplant placement. They also offer theadvantage of immediate temporiza-tion; the patient thus avoids the use ofremovable provisional appliances orthe need to go edentulous until theimplant fully osseointegrates and isable to be restored. In the current ret-rospective study, implants were nonoc-clusally loaded immediately afterplacement of a provisional restorationfor a period of 4 to 6 months beforedefinitive impression and restoration.Each of the 48 NDIs has been in func-tion for 1 to 5 years.

The 100% success rate of NDIs asused and documented in the presentstudy is similar to that observed byMazor and colleagues,23 who reportedon 32 single-tooth replacements in 32patients. One implant failed as a resultof “mechanical overload.” Several dif-ferences, however, should be notedbetween the two studies. The implantsused in the Mazor et al study were all2.4 mm in diameter. All were immedi-ately loaded at the time of placement.The implants used in the present studywere 1.8, 2.2, or 2.4 mm, dependingon the volume of remaining bone. Theadditional option of using a smaller-diameter implant in the present studyallowed preservation of more bone inthe implant site, both buccally andinterdentally. The implants used in thecurrent study (ANEW, Dentatus) allow

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immediate loading and have beenused with this protocol for multipleimplants. However, in the presentstudy, for the replacement of one ormore teeth in patients who hadenough remaining teeth to provide astable, trauma-free occlusion, theauthors felt that there was little need toload these implants early and riskmacromovement with loss of osseoin-tegration. The immediate, nonocclud-ing provisional provided for estheticsand performed as a space maintainer,thus avoiding adjacent tooth migra-tion. The NDI system employed in thepresent study also has the advantageof delivering a screw-retained definitiverestoration. This provides an option

for retrievability, which is extremelyuseful should the crown requirereplacement because of porcelain frac-ture, chipping, or the desire to changeporcelain color when the color of theadjacent teeth changes. The latter mayoccur as a result of aging, professionalor home whitening procedures, orfuture additional restorations. TheseNDIs present a useful adjunct to theimplant restorative armamentarium byproviding an implant option in patientswith congenitally missing incisors,reduced interdental space followingorthodontic movement, retained pri-mary incisors that are lost, one or twomissing mandibular incisors (Figs 2ato 2c), or space collapse in the maxil-

lary anterior area following a lack ofneeded orthodontic therapy.

Although there are several NDIsystems available today, the data inthe present study with the acrylic resinscrew cap–retained system demon-strate similar high survival rates for the1.8- to 2.4-mm-diameter implants.24

The advantage of the NDI systemused in the present study is that it offersthe same ease of insertion with agreater prosthetic flexibility and retriev-ability than purely cementable sys-tems. Evaluation of these NDIs forlong-term use will require additionalmulticenter prospective longitudinalstudies.

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Fig 2a Preoperative view of the missingmandibular left central incisor tooth.

Fig 2c Implant with a screw-retainedmetal-ceramic restoration.

Fig 2b Radiograph of the NDI (2.4-mmdiameter and 10-mm length) with the index-ing abutment.

References

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2. Adell R, Eriksson B, Lekholm U, BrånemarkPI, Jemt T. A long-term follow-up study ofosseointegrated implants in the treatmentof totally edentulous jaws. Int J OralMaxillofac Implants 1990;5:347–359.

3. Jemt T, Lekholm U. Oral implant treatmentin posterior partially edentulous jaws: A 5-year follow-up report. Int J Oral MaxillofacImplants 1993;8:635–640.

4. Buser D, Mericske-Stern R, Bernard JP, etal. Long-term evaluation of non-sub-merged ITI implants. Part 1: 8-year lifetable analysis of a prospective multi-cen-ter study with 2359 implants. Clin OralImplants Res 1997;8:161–172.

5. Buser D, Mericske-Stern R, Dula K, LangNP. Clinical experience with one-stage,non-submerged dental implants. Adv DentRes 1999;13:153–161.

6. Andersson B, Odman P, Lindvall AM,Lithner B. Single-tooth restorations sup-ported by osseointegrated implants:Results and experiences from a prospec-tive study after 2 to 3 years. Int J OralMaxillofac Implants 1995;10:702–711.

7. Cooper L, Felton DA, Kugelberg CF, et al.A multicenter 12-month evaluation of sin-gle-tooth implants restored 3 weeks after1-stage surgery. Int J Oral MaxillofacImplants 2001;16:182–192.

8. Ekfeldt A, Carlsson G, Borjesson G. Clinicalevaluation of single tooth restorations sup-ported by osseointegrated implants: A ret-rospective study. Int J Oral MaxillofacImplants 1994;9:179–183.

17. Grunder U. Stability of the mucosal topog-raphy around single-tooth implants andadjacent teeth: 1-year results. Int JPeriodontics Restorative Dent 2000;20:11–17.

18. Tarnow DP, Cho SC, Wallace SS. The effectof inter-implant distance on the height ofthe inter-implant bone crest. J Periodontol2000;71:546–549.

19. Esposito M, Ekestubbe A, Grondahl K.Radiological evaluation of marginal boneloss at tooth surfaces facing singleBrånemark implants. Clin Oral ImplantsRes 1993;4:151–157.

20. Froum SJ, Emtiaz S, Bloom M, Scolnick J,Tarnow D. The use of transitional implantsfor immediate fixed temporary prosthe-ses in cases of implant restorations. PractPeriodontics Aesthet Dent 1998;10:737–746.

21. Petrungaro P. Fixed temporization andbone augmented ridge stabilization withtransitional implants. Prac PeriodonticsAesthet Dent 1997;9:1071–1078.

22. Froum SJ, Simon HH, Cho SC, Elian N,Rohrer M, Tarnow DP. Histological evalua-tion of bone-implant-contact of transitionalimplants loaded for various time periods.Int J Oral Maxillofac Implants 2005;20:54–60.

23. Mazor Z, Steigmann M, Leshem R, PelegM. Mini-implants to reconstruct missingteeth in severe ridge deficiency and smallinterdental space: A 5-year case series.Implant Dent 2004;13:336–341.

24. Blaard A, Vanvr JB. Multi-clinic evaluationusing mini-dental implants for long-termdental stabilization: A preliminary biomet-ric evaluation. Compend Contin EducDent 2005;26:12:892–897.

9. Henry PJ, Laney WR, Jemt T, et al.Osseointegrated implants for single-toothreplacement: A prospective 5-year multi-center study. Int J Oral Maxillofac Implants1996;11:450–455.

10. Levine RA, Clem D, Beagle J, et al.Multicenter retrospective analysis of thesolid-screw ITI implant for posterior sin-gle-tooth replacements. Int J OralMaxillofac Implants 2002;17:550–556.

11. Lekovic V, Kenney EB, Weinlaender M, etal. A bone regenerative approach to alve-olar ridge maintenance following toothextraction: Report of 10 cases. JPeriodontol 1997;68:563–570.

12. Lekovic V, Camargo P, Klokkevold P,Weinlaender M. Preservation of alveolarbone in extraction sockets using bioab-sorbable membranes. J Periodontol1998;69:1044–1049.

13. Schropp L, Kostopoulos L, Wenzel A. Bonehealing following immediate versusdelayed placement of titanium implantsinto extraction sockets: A prospective clin-ical study. Int J Oral Maxillofac Implants2003;18:189–199.

14. Pietrokovski J, Massler M. Alveolar ridgeresorption following tooth extraction. JProsthet Dent 1967;17:21–27.

15. Nevins M, Mellonig JT, Clem DR III, ReiserGM, Buser DA. Implants in regeneratedbone: Long-term survival. Int JPeriodontics Restorative Dent 1998;18:35–45.

16. Fugazzotto PA. Success and failure rates ofosseointegrated implants in function inregenerated bone for 6 to 51 months: Apreliminary report. Int J Oral MaxillofacImplants 1997;12:17–24.

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