Review for the two implant - Open.Michigan · dental surveyor positioned over the proposed implant site. Our next step is the fabrication of a record base to house our radiographic

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Review for the two implantretained overdenture

Now that you have all hadmore experience in clinic, youshould be able to both retainmany of the relevant points

better and place them incontext better as well.

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A Review Complete Denture Two ImplantSupported Overdenture Treatment

Source: Jeff Shotwell, University of Michigan, 2008

Getting FromHere

To Here


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This is a cut away denture forclarity. Measure the existingdenture the patient is wearing.We want to know what thedistance is from the crest ofthe ridge in the anterior areato the height of the occlusalplane.

Having had the patient wear aprovisional denture for sometime helps us in this area agreat deal.


In addition to taking the measurement mentioned inthe previous image,we obtain a study model and makea radiographic template with markers in the proposedposition of the implants

To Construct TheTemplate, We PositionTwo Stainless SteelMarkers 10mm inLength In A Triad®Record Base


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Using our study cast, we mark the midline and thenmeasure laterally 7-8mm each way from the midline forthe proposed location of our implants. Why pick thisdistance and in this location?


With this configuration, should the patient everdecide to have more implants placed, the position isideal for 5 lower implants which could support a fixedlower appliance.

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If the location of the implants is in the area previouslyoccupied by the cuspid teeth, we may not have spacefor three implants between them. We may also nothave any room distal to the implants withoutinterference from the location of the mental foramen.

In addition to the mesial-lateral position of theimplants, we are also concerned with the angulation ofthe implants. As shown in the images above, we arealso concerned with the width of the alveolar ridge inthe proposed implant location.

At this angulationthe implant would bewell positioned inthe mandible. Whatabout width of ridgecrest?

The angulationshown here is wellpositioned in themandible. Whatabout width of ridgecrest?

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Lower cast mounted in thetable of a dental surveyor.The orientation and locationof the proposed implantlocation has beendetermined. Here we havea 2.0mm drill blank in thedental surveyor positionedover the proposed implantsite. Our next step is thefabrication of a recordbase to house ourradiographic markers.


Triad® material is used to make a record base and wethen cut out an area in the area of the proposedimplant placement. We will use Triad Gel® material torefine this area of our radiographic guide.


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The model is repositioned on the surveyor tableand the drill blank positioned as is was before inthe area of the proposed implant location.


The sequence above shows placement of Triad Gel®material in the cut out spaces in the record base onthe left image. The center image shows theplacement of the drill blank in the uncured gel and theimage on the right shows the curing of the gel aroundthe drill blank. Remember: location, location location


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We loosen the knurled nut holding the drill blank inthe surveyor, lift the surveyor vertical spindle andthen take pliers and remove the drill blank from thecured Triad Gel®


We follow the same procedure for the secondimplant location.


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Two blanks that are2mm in diameter by10mm in length

The two mm in diameter drill blank used to createthe hollow area in the record base.

Having made the two hollow areas in the record base,we will remove the drill blank from the secondproposed implant location and insert two dowels thatare 2mm in diameter by 10mm long. These will serveas markers for our pre operative radiographicassessment.


This radiographic guide now has two markers of a knownlength in the position and the orientation of ourproposed implant location. Let’s take a radiographic andsee how it all lines up prior to making surgical guides.


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In this case we were working with mounted modelsand could create a template that the patient couldbite on to stabilize. Movement of the templateduring the taking of the radiograph is a problem.


Mental Foramina

Orientation of the guide pinsparallel to one another and in a goodlocation relative to the midline andthe mental foramina.

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For the lower overdentures, we take a lateralcephalogram as well as a panorex film to verify thelocation and orientation of the proposed implantplacement. Once this has been verified to line up well,we can proceed with the fabrication of the surgicalguides.

Surgical guides are made in the same manner that theradiographic guide was made. The 2.2mm diameterdrill blank and the 2.8mm diameter drill blank fit inthe surveyor just like any tool you would use in thesurveyor.


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In the case of the drill guides, we do not cover thelabial aspect of the drill blank. We cure thematerial and use an acrylic bur to open the guide tothe buccal for access during the surgical procedure.


Once our drill blanks go above 3.0mmin diameter, they will no longer fit inthe dental surveyor. We need to usean alternate means of stabilizing andholding the drill blank.


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By removing the knurled nut and holdingdevice, we may position larger drillblanks along the slot in the verticalspindle of the dental surveyor. Now weneed to hold and stabilize the drillblank in this position.


The desk has modified spring clampsto hold the drill blanks larger than3mm in diameter firmly against theslot in the surveyor spindle.


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Open to the labial which allows thesurgical drill easy access.

There is still a small constriction whichneeds to be removed on this side.


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When the guides are completed, theyare placed on the model to confirmthat the position of the guide iscentered on the proposed implant site.


Don’t forget that a significantpart of the process is knowingwhere the plane of occlusion willbe in your lower denture. Don’tlose sight of the need for thisinformation.


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The two surgical guides on the left were made by inserting the drill blanks inthe surveyor as any surveyor tool would be placed. The guide on the right usedthe clamp to hold the 3.5mm drill blank.

The guides are delivered to the surgeon who places the implants. Three monthslater having followed the patient and placed soft liner in the lower denture overand around the implant healing caps we are ready for the next phase of ourtreatment with the patient


Using the surgical guides gives us two implants placed inthe area of the lateral incisors. The implants areproperly spaced and oriented parallel with one another.


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The cover screws placed at the time of surgery areremoved with a screwdriver designed specifically forthe purpose. This procedure is performed threemonths following the placement of the implants.


The driver for the retentiveanchor is triangular at theend. This driver fits into thetop of the retentive anchorcircled in the image at theleft.


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The driver is placed in a torque wrench to place theretentive anchor in the implant at a specified torquesetting specifiec by the manufacturer. The specifiedtorque is such that the anchor will not come loose infunction.

The torque is specified by the deflectionof this flexible shaft and read byalignment with marks on the short arm offthe main body of the driver.


Torque driver components

Abutment being tightened to35Ncm


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The deflection of the flexibleshaft is seen close up. We must“flex” the torque indicator to thethird mark indicating 35Ncm oftorque applied to the abutment.


The retentive anchorsonce placed will be used toretain the denture. Thelower image is an occlusalview showing thealignment of the retentiveanchors and the implants.


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The silver colored cap is theretainer housing for polymerinserts which provide retentionfor the denture. The stainlesssteel cap is secured in thedenture using self cure acrylic.


The inner aspect of the lower denture is relieved toallow a passive fit over the retentive anchors. Thedenture is tried in the patient’s mouth to ensure apassive fit. The retentive caps will then be “picked up”in the mouth using self cure acrylic.


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When the self cure acrylic is placed in therecesses in the denture, allow it to get a little“stiff” (it looses it’s gloss) and then place it in themouth and have the patient close in MIP holdingfor approximately 5 minutes.


The black colored insert is used to position thestainless steel cap on the retentive anchors for thepurpose of “pick up” in the denture. The image at theright shows the retentive anchors in place in thedenture. The other inserts shown at the left providediffering amounts of retention. The white neoprenegasket shown at the left protects from having theself cure acrylic “lock on” the implant / abutment inthe mouth.


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The patient withthe retentiveanchors placed inthe denture.


Patient #2

Upper Partial Denture

Lower Arch Down To Last ToothWhich Needs To Be Extracted

Choices?

Conventional Denture

Implant Retained Overdenture


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The images at the right showthe clinical appearance of theridge with the last remainingtooth.

The next two images show acast of the lower arch withthe tooth removed and drillguides placed in the proposedplacement sites of the twoimplants. Note that theguides are parallel to oneanother and perpendicular tothe plane of occlusion.


A surgical guide is fabricatedfrom self curing acrylic orTriad® material. The drillguide surrounds the lingualhalf of the drill. This allowsthe surgeon easy access duringsurgery for visibility as well asirrigation. The images shownhere do not yet have thematerial adapted to the lingualhalf of the drill guides.


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The surgical images seen at theright show the implant sitesfirst with the depth guides inplace at the top image.

The center image shows theimplants in place with theirhealing screws in place.

The bottom image shows thesurgical site just prior toclosure with bone graft materialin place around the defect atthe labial of the implant in thearea of #27.


The ridge after closure and after a week to 10 days ofhealing. The lower temporary denture was relined withtru-soft temporary liner at that time.


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The image above shows thepatient after two weeks ofhealling. The images at theright show the patient’s ridgeafter three months of healing.The retentive anchors will nowbe placed in the implants.


The image at the right shows a temporary denturerelined with fresh tru-soft around the implantretentive anchors. The denture at the right isn’t fromthe same patient as the image at the left, but thetreatment was the same.


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The completed denture along with the temporarydenture are shown in the left image. The new denturein place shows the posterior teeth set in cross-bite.


Close up image of the retentive caps in the completeddenture. Note the polymer rings in place around the goldretentive cylinders. The image at the right showsadjusting tools for the retentive clips.


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The initial height ofthe implants createda situation in whichthere was minimalacrylic covering theretentive caps in thefinished denture.

At the time of implant placement, if more of theresidual ridge had been reduced we would not have thesituation seen above. This minimal acrylic coverage ofthe retentive anchors causes maintenance issues.

You can see that we have little acrylic over theretentive anchor caps especially on the patient’sright side.

Source: Jeff Shotwell,

University of Michigan, 2008

A brief review of the steps taken to treat the patient.


Documents

Review for the two implant - Open.Michigan · dental surveyor positioned over the proposed implant site. Our next step is the fabrication of a record base to house our radiographic