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Case Report

clinical

Immediate Implant Placement in Deficient Bone Sites

IntroductionThe presence of a low-lying sinus floor and inadequate bone volume often precludes the successful placement of

implants. The following Case Report describes a protocol for an immediate placement of a maxillary molar im-

plant where the vertical height of bone is inadequate due to the presence of the sinus floor. The following pro-

tocol for predictable immediate molar implant placement and concurrent sinus augmentation relies on the

principles of osteogenesis upregulation through the use of growth factors and particulate osseous grafting.

This particular method consists of the following steps:

• extraction of the tooth

• immediate crestal approach sinus graft using bovine mineral and plasma rich in growth factors (PRGF)

• immediate implant placement

• particulate bone grafting in conjunction with the use of PRGF

• three to four months of healing

• attachment of the final prosthesis.

In contrast to a more traditional staged approach, this case illustrates how time and expense can be reduced using

this immediate placement protocol.

Raj ChopraBSc, DDS

A 43-year-old healthy male presentedwith an initial complaint of a frac-tured upper right tooth and sponta-neous intermittent sensitivity. Hismedical history was non-contributoryas he was taking no medications andwas not being treated for any ill-nesses. Tooth #16 was originally endodon-

tically treated due to carious pulpalexposure. Ten years later it was en-

dodontically re-treated due to the de-velopment of an acute infection. Sixmonths after the re-treatment, thecoronal portion of #16 fractured atthe level of the gingiva. At this point,radiographic examination revealed anapparent periapical periodontitis andthe tooth was deemed non-restor-able. Upon evaluation, tooth #16 wasgiven a hopeless prognosis and con-sent was obtained from the patient for

extraction with immediate implantplacement1,2,3 as well as a modified SA2sinus elevation procedure.4

Prior to extraction, two 9 mL vialsof blood were drawn from the pa-tient’s left antecubital fossa. Thesewere used to generate the plasma richin growth factors (PRGF)5 to be usedduring the surgery.

CASE REPORT

THIS ARTICLE HAS BEEN PEER-REVIEWED.

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Clinical Procedures

Figures 1 & 1a – Initial clinical andradiographic appearance of tooth #16.

Figure 2 – Tooth was sectioned andextracted using a periotome and for-ceps technique in order to maintaininterseptal and buccal bone walls.

Figure 3 – An osteotomy was createdin the mid-interseptal bone. The os-teotomy was advanced to include thefloor of the sinus.

Figure 4 – The F1 fibrin-rich bio-genic membrane derived from the pa-tient’s plasma. This membrane isobtained by centrifuging the patient’sblood and withdrawing the superiormost fraction, which is considered tobe most highly concentrated with fib-rin. This layer, which is referred to asthe F1, is then coagulated using cal-cium chloride to create a homologousmembrane.6

Figure 5 – A fibrin-poor biogenicmembrane derived from the patient’splasma with particulate bovinexenograft integrated within it. Aftercentrifugation, the fibrin-poor layer(known as the F2 layer) of the pa-tient’s plasma is used and coagulatedwith the added mineralized xenograft.

Figure 1

Figure 1a

Figure 2Figure 3

Figure 4 Figure 5

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Figure 6

Figure 6 – The F1 fibrin-richplasma membrane is placed firstinto the osteotomy and pushed api-cally to form the new sub-antral floor.It can also repair any microscopictears or perforations of the Schneider-ian membrane.

Figure 7 – The F2 or fibrin-poorplasma membrane containing themineralized xenograft is then placedinto the osteotomy and also pushedapically into the floor of thesinus. This will act as the sinus graftand form new bone around the apexof the implant. It has been shownthat bovine mineral alone will formnew bone in the maxillary antrum.7,8,9

In this technique, the addition of bi-ologic modifiers (growth factorsfound in the patient’s own plasma,from the F2 layer) should have a pos-itive influence on the predictability,quality and speed of maturation ofthe newly-formed bone.

Figure 8 – View of PRGF and graftplaced in extraction socket and intosinus floor.

Figure 9 – A 5.6 x 10.5 mm taperedLaser-Lok Biohorizons implant isdipped in the growth factor richplasma layer creating a bioactive sur-face.10 A cortico-cancellous allograftcan also be seen in the bowl soakingin this layer of the patient’s plasma,which was drawn up from the plasmaclosest to the sedimented red bloodcells after centrifugation. This graftwas used to partially fill in the bonydefects around the implant body.

Figure 10 – View of final implant po-sition in the extraction socket.

Figure 11 – Additional heterologousgraft (mineralized xenograft integratedF2) was used to fill bony deficiencies.

Figure 12 – Final view of implantsurrounded by grafting material. Afreeze-dried bone allograft soaked inthe growth factor rich plasma wasalso used to fill the defects.

Figure 7

Figure 8Figure 9

Figure 10

Figure 11

Figure 12

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Case Report

Figures 13 & 14 – The remainingfibrin-rich F1 membrane was used asan occlusive dressing on top of thesocket. A Gelfoam hemostatic spongewas placed on top and sutured inplace in order to ensure all previousgraft materials remained secure.

Figure 15 – Final post-surgical radi-ograph of implant fixture.

Figure 16 – Ten-day post-operativeview shows fibrin membrane still wellin place and initial epithelial creep.

Figure 17 – Post-operative view at 10weeks.

Figures 18 & 18a – Healing abut-ment in place at 10 weeks post-opera-tively. Healthy and robust appearanceof soft tissue cuff at three monthspost-operatively.

Figure 19 – Stock Biohorizons 3-in-1abutment placed at crown cementa-tion appointment.

Figure 13Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 18a

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Figure 20 – Cotton pellet placed inabutment screw hole to prevent thecement from obstructing access to theabutment screw.

Figure 21 – Resin cement used tolute crown to abutment. This tech-nique circumvents the need for a castUCLA abutment style screw-retainedcrown. Screw-retained implant crownscan be created by asking the labora-tory to provide an opening on the oc-clusal surface of the porcelain-fused-to-metal crown. As a result, the costof the final prosthesis is greatly re-duced. The cost to have this type ofcrown fabricated would be similar tothe cost of a cement-retained crown,while having the advantages of screwretention, such as no excess cementextrusion into the soft tissues.

Figure 22 – The crown is seated onthe abutment and excess resin cementover the screw hole is quickly re-moved using an explorer. MaxcemElite (Kerr) was used here to create anextremely strong bond between the titanium abutment and the metal ceramic crown.

Figure 23 – The patient is instructedto bite tightly on a cotton roll for fourto five minutes for complete cementsetting as per the manufacturer’s instructions.

Figure 24 – Intra-oral view of ce-mented crown.

Figure 25 – The crown (now luted tothe abutment) is removed by un-screwing the abutment screw.

Figure 26 – Intra-oral view of implant.

Figure 20

Figure 21

Figure 22

Figure 23

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Figure 26

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Figure 27 – Excess cement is removedfrom the crown-abutment assembly.

Figure 28 – Modified “screw-re-tained” crown is torqued to manufac-turer’s recommended level (30 Ncm).

Figure 29 – A cotton pellet is placedin order to prevent the final restora-tive material from bonding to thehead of the abutment screw.

Figure 30 – A composite restorationis placed to seal the screw hole, theocclusion is checked, and the restora-tion is finished/polished.

Figures 31 & 32 – Final implantcrown appearance. A three-monthpost-crown insertion follow-up re-veals good emergence profile andhealthy gingiva.

SummaryAs shown in this case, there are someadvantages to following an acceler-ated implant placement procedureand a simplified prosthetic protocolfor screw retention. From a surgicalperspective, the most important ad-vantages are:• fewer surgeries and therefore de-creased cost to the patient com-pared with the traditional approachof extraction, waiting for sockethealing, bone grafting and sinus el-evation and finally implant place-ment

• shorter total treatment time, com-pared with the traditional approach

The key benefits from the describedprosthetic approach are:• elimination of excess cement extru-sion into the soft tissues versus tradi-tional cement-retained restorations

• lower cost for the dentist of a“screw retained” restoration

Overall, this protocol has been shownto be a predictable, less expensive andquicker option when compared withthe traditional approach. It is a proto-col from which, in my view, both thepractitioner and the patient may real-ize a significant benefit.

Dr. Chopra is a 2000 graduate of the Schulich School of Medicine & Dentistry atWestern University. He is a Fellow of the International Congress of OralImplantologists and currently maintains a private practice in Mississauga, Ontario.Dr. Chopra may be reached at 905-270-0007 or at rchopra1@gmail.com.

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Figure 32Figure 29

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References

1. Lazzara, R. Immediate implant place-ment into extraction sites: surgicaland restorative advantages.International Journal of Periodonticsand Restorative Dentistry. 1989;9(5):332-43.

2. Gelb, D. Immediate implant surgery:three-year retrospective evaluation of50 consecutive cases. InternationalJournal of Oral and MaxillofacialImplants. 1993;8(4):388-99

3. Rosenquist, B., Grenthe, B. Immediateplacement of implants into extrac-tion sockets: implant survival.International Journal of Oral andMaxillofacial Implants. 1996, Feb:205-209.

4. Misch, C.E. Contemporary ImplantDentistry: 2008: 905-974.

5. Anitua, E., Sanchez, M., Oriva, G.,Andia, I. The potential impact of thepreparation rich in growth factors(PRGF) in different medical fields.Biomaterials. 2007;28:4551-60.

6. Anitua, E., Alkhraisat, M., Orive, G.Perspectives and challenges in regen-erative medicine using plasma rich ingrowth factors. Journal of ControlledRelease. 2012;157:29-38.

7. Valentini P., Abensur, D.J. Maxillarysinus grafting with anorganic bovinebone: A clinical report of long-termresults. Int J Oral Maxillofac Implants20O3;18:556-560.

8. Piatelli, M., Favero, G., Scarano, A.,Orsini, G., Piatelli, A. Bone reactionsto anorganic bovine bone (Bio-Oss)used in sinus augmentation proce-dures: A histologic long-term reportof 20 cases humans. Int J OralMaxillofac Implants 1999;14:835-840.

9. Valentini, P., Abensur, D., Densan,D., Graziani, J.N., Hammerle, C.Histological evaluation of Bio-Oss ina sinus floor elevation and implanta-tion procedure: A human case report.Clin Oral Implants Res 1998;9:59-64.

10. Anitua, E. Enhancement of osseoin-tegration by generating a dynamicimplant surface. J Oral Implant 2006;32:72-76.

Case Report