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Traditional implant mainte-nance has in the past includ-ed clinical assessment of

plaque control and radiographicevaluation of the crestal bone levels.

Additionally, it was important todetermine the integrity of the con-nection of the prosthesis to the abut-ment and the abutment to theimplant body.

Spring

The Realities of DentalImplant Maintenance

From Our Officeto Yours...

Implant dentistry can effectivelymeet the restorative needs of fullyand partially edentulous patients.However, both the implants and therestorations they support can fail inresponse to local and systemic etio-logic factors.

The ability to assess the reac-tion of the peri-implant tissues andmaintain their health is affected byimprovements in the biology andmechanics that affect implant den-tistry.

Implants are being fabricatedfrom a variety of materials and theirsurfaces modified to enhance integra-tion. The restorative components arebeing revised to facilitate clinical pro-cedures and improve esthetics.

In th is cur ren t i ssue o fThe PerioDontaLetter, we focus onthe assessment essential to preclud-ing the onset of disease in the peri-implant tissues and protecting therestorative componentry.

As always we welcome yourcomments and suggestions.

The advent of single tooth andcemented restorations, early andimmediate loading, the variety ofabutment designs, and a shift in focusto more cosmetically-acceptablerestorations has necessitated thedevelopment of changes in the con-cepts in implant maintenance.

To ensure the continued mainte-nance of optimum intraoral health,

Figure 1. Who sayscalculus can’tform onimplants?

I. Stephen Brown, D.D.S. 220 South 16th Street, Suite 300, Philadelphia, PA 19102 (215) 735-3660

The Brown

I. Stephen Brown, D.D.S., Periodontics & Implant Dentistry

progress more laterally, frequentlyextending directly into the bone marrow.

Evaluation of the peri-implantmucosa begins by determining whetherthe tissue is keratinized or non-kera-tinized. In some cases the lack of kera-tinized tissue around an implant canlimit the patient’s plaque control habitsdue to increased discomfort. Digitalpalpation of the tissue in the vicinity ofthe margin can reveal the presence ofbleeding or suppuration.

The contours of the restoration andthe emergence of the implant head attimes may limit access or interfere withlong axis placement of the probe.Thread design, the implant contours andthe texture of the implant surface canrestrict the path of the probe tip.

Implants are often placed deeperthan would be the location of the CEJ ofa tooth, especially in the esthetic zone,to permit development of an optimalemergence profile and contours of therestoration. If the proximal crestal bonelevels of the adjacent teeth are morecoronal than the implant platform, non-

the dental team must understand how toassess the health of the peri-implant tis-sues, the alveolar bone housing and thecommon restorative components asso-ciated with dental implants.

Following are some importantissues to be considered at every dentalimplant maintenance appointment.

Peri-Implant Anatomyand Probing

Probing around implants is contro-versial. If probing is performed, the clin-ician should use light probing forces tak-ing care not to detach the junctionalepithelium or the connective tissue fibers.

Clinically and histologically, thesoft tissue around teeth and implantsresemble each other. Both are coveredby epithelium and form a crevice whichterminates apically at the junctionalepithelium which is attached to thetooth and implant respectively. Theepithelium is attached by a hemidesmo-somal attachment similar to the junc-

tional epithelial attachment on the sur-face of a natural tooth.

However, the connective tissuebetween the junctional epithelium andthe crest of the bone differs in severalrespects as a result of the absence of aperiodontal ligament and cementumaround an implant.

The peri-implant connective tissuecontains more collagen and fewerfibroblasts and blood vessels as com-pared to the gingival tissue surroundinga tooth. The connective tissue aroundthe implant is adherent and the collagenfibers run parallel to its surface. In con-trast, the fibers within the connectivetissue around teeth insert into thecementum of the root as Sharpey’sfibers which creates a much strongerconnective tissue attachment.

This structural dichotomy in theconnective tissue relationships helps toexplain the differences in response tothe presence of inflammation. Theinflammatory lesion around implantscompared to that around teeth has beenshown to be larger in size and to

Figures 2 and 3. The extreme subgingival placement of this implant and the proximity of the microgapto the bone at the abutment implant interface contributed to this osseous defect.

PerioDontaLetter, Spring

pathologic interproximal “pockets”may be as deep as 6-7mm withoutnecessitating corrective treatment. Werecommend that supportive periodontal-implant maintenance visits be sharedwith the periodontist to ensure that nec-essary intervention is never delayed.

Bacteria

In treating partially-dentate patients itis especially important that they be in opti-mum periodontal health and periodontaldisease is under control before dentalimplants are placed. We recommend aconsultation between the primary care den-tist and the periodontist, including analysisof pertinent diagnostic records, prior to thedevelopment of the treatment plan.

Crucial to the success of an implantrestoration is the patient’s plaque con-trol and debridement by the hygienist.Various studies clearly show that lack ofeffective plaque control results in peri-implantitis and adversely affects thesuccess rate of the implant and implant-supported restorations.

A healthy implant crevice will havea microbial flora consisting predomi-nately of gram-positive cocci and non-motile rods. Diseased implant crevicesexhibit populations of gram-negativeanaerobic rods and spirochetes, similarto the periodontal pathogens found inpockets associated with periodontitisaround natural teeth.

There are also significant micro-bial differences between the fully andpartially dentate patient. The teethmay harbor putative periodontalpathogens and serve as a bacterialreservoir which ultimately contributeto colonization around the implants. Arecent paper documents a more specif-ic trend in which such organisms aretransmitted from teeth to implants inthe same arch.

Restoration Stability

The integrity and stability of therestoration must be checked periodical-ly to determine cement wash out, screwloosening or fracture, damage to the

integrity of the prosthesis and, occa-sionally, fractures of the implant body.

Any lateral or apical-coronalmobility of an implant is generallysynonymous with the loss of integra-tion. Evaluating mobility is particu-larly important if one encounters anyof the well-known clinical signs ofperi-implant inflammation. Radio-graphic changes suggesting loss ofalveolar height or bone alongside thesurface of the implant body alsodemand further examination. Radio-graphs are also reliable indicators ofalterations in the integrity of compo-nent connections.

Perhaps the most significant find-ing is ANY DISCOMFORT reported bythe patient or elicited when “stressing”the implant, by pushing, torquing, orwhile in function.

Some of the most important aspectsof the restoration to evaluate are:

• Status of surface material (frac-tures/chipping of porcelain/composite)

• Integrity of solder joints• Loss of cement seal

Figure 4. Peri-implantitis has caused significantinflammation of the gingival tissues with markedplaque deposition and recession characterized byunderlying bone loss resulting in substantialexposure of the implant body.

Figure 5. Mesial bone loss and subgingivalinfection will likely lead to the loss of thisimplant.

• Loose screws or fractures• A tight seal on screw access holes• Occlusal relationships (guidance,

interferences, etc.)• Excessive wear patterns on the

restoration or opposing occlusionOne of the most destructive and

potentially devastating findings is thatof subgingival cement. Due to theextremely close fit of a cast restorationto a milled implant abutment, specialcare and excellent technique is essentialduring and immediately after cementa-tion. This can be most challenging insituations where implants are intention-ally placed deep for cosmetic purposes.

Movement of an implant-supportedrestoration may signal:

• Inaccurate fit of the superstructureleading to potential damage or fractureof the restoration

• Loose screws subject to deforma-tion and fracture

• Persistent irritation of the sur-rounding soft tissues, leading to failureof the junctional epithelial attachment

• Parafunctional habit patterns

The Possible Significanceof the “Micro-Gap”

Many longitudinal studies havesuggested that marginal recession andcrestal bone loss may occur over time,even in a well-integrated implant. It hasbeen suggested that this may be relatedto peri-implant inflammatory changes,which may be associated with themicro-gap and the formation of a bio-logic width among other possibilities.

The term micro-gap usually refersto the junction of the interface betweenthe abutment and the implant platformor the marginal adaptation of therestoration to the abutment. The “gap”is often located subgingivally and itmay provide a locus for plaque reten-tion and colonization of pathogenic bac-teria. We must be eternally vigilantbecause the presence of subgingivalbacteria can be destructive to implantsas it is to natural teeth.

Radiographs

We have found vertical bitewingsand parallel periapical films are essen-tial to evaluate crestal bone levelsaround implants. These may be as use-ful as probing to determine interproxi-mal health or disease around implants.

Our suggested protocol is to obtaina baseline film at the time of insertion ofthe final prosthesis, retaken six monthsand one year thereafter, and then everytwo years hence. This frequency shouldbe altered to fit the individual needs ofeach patient and especially in the face of

systemic and/or clinically observedchanges.

Crestal bone changes within thefirst year the implant restoration isloaded should be no greater than2.0mm, depending upon the implantsystem. Subsequent changes in crestalbone levels should be limited to0.1mm/year. Since accurate and repro-ducible measurements of this magni-tude (less than 1mm) are difficult toassess clinically, any observable radi-ographic changes should be treatedpromptly and aggressively, with anemphasis on the specific etiology of theattachment loss.

Systemic Influences

Certain systemic influences mayinterfere with osseointegration andadversely affect implant prognosis. Asa patient’s systemic condition changesfor the worse, negative influences onlocal etiology and the physiologicresponse of the surrounding soft tissuesand bone are not unusual. Smoking andmany medications also affect oral flora,soft tissue and bone metabolism.

Common systemic diseases such asdiabetes and osteoporosis have beendemonstrated to affect the bone-to-implant contact. It is well known thatmedications such as calcium channelblockers and immunosuppressants mayhave a profound effect on the inflam-matory response of the peri-implantenvironment. Bisphosphonate drugsused to treat a variety of bone metabo-lism disorders can also lead to bisphos-phonate-related osteochemonecrosis(BROCN) of the jaws, following toothextraction.

As with any patient, a regular,updated medical history is of criticalimportance.

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Figure 6. Radiographic evidenceof a fractured implant. Bone losscan be seen to have progressedapically to the fracture.

ImplantFracture

I. Stephen Brown, D.D.S. 220 South 16th Street, Suite 300, Philadelphia, PA 19102 (215) 735-3660