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ePaper created 2015-03-04, 10:43:31 | version 1.33.01
through mechanical debridement and copious irriga- tionwithBetadine®.Amaxillarycompleteoverdenture was fabricated and placed on the same day of the ex- tractions. Afterahealingperiodof4months,Dentascanswere obtained to evaluate the bone heights. The scans showedsignificantboneresorptionintheposteriorsec- tors of the maxilla (Figs. 2a–c): SA-4 according to the Misch classification, since classification was a residual ridgeheightlessthan5mm.Sinusgraftingwasneces- sary and implant placement had to be delayed by 5-6months,untilcompletehealingandgoodinitialsta- bility were achieved. Bilateral sinus lift was performed under local anaesthesia from a lateral approach using thetechniquedescribedbyTatum.TheSchneidermem- brane was gently lifted. As there were no perforations, PRFwasusedforcoverageofthesinusfloor.Maxgraft® allografts were placed to elevate the maxillary sinus floor,andthencoatedwithaBio-Gide®collagenmem- brane and PRF. After a healing period of 5 months, the patient underwent CT scan, wearing the scan prosthe- sis that consisted in acrylic resin and commercially availableteethforvisibilityofthedesiredtoothlocation in CT images (Fig. 3). CT examination showed an ade- quatebonevolumeinthegraftedposteriorregions,and an even sinus floor with homogeneous allografted ar- eas.Thedome-likeshapeofthevestibulo-lingualcross- sectionswasindicativeoftheabsenceofmaterialleak- ageintothemaxillarysinuses(Fig.5a). _Osteogenic activation I performed an osteogenic activation of the processed Maxgraft® bone used for sinus lift elevation usingthetechniquedescribedbyScortecci.Atranspari- etal approach was used for insertion of the matrix os- teotensorsfollowingaminimally-invasiveflaplesspro- tocol(Fig.4).Endostealstimulationresultsinosteogenic activationandallowstheevaluationofthemechanical strengthofthegraftedareastoprobing.Thankstothis simple and minimally-invasive technique, the initial quality of the future recipient bone site is easily as- sessed.Thesetechniqueshavebeensuccessfullyusedin orthopaedics for ten years. In view of the excellent re- sponsetoosteogenicactivation,itwasdecidedthatim- plantswouldbeplaced45dayslater. _Treatment planning The case was planned in the SIMPLANT® treatment planningsoftware.Thescanprosthesisiscriticalforde- terminationofthecorrectpositionandaxialalignment of the implants, visualisation of the emergence profile, anddeterminationofthesize,positionandaxialalign- ment of the abutments. Furthermore, it allows making themostuseoftheavailableboneheight.Atthisstage, special attention should be paid to 3-D positioning of theimplantsandmorepar- ticularly to the emergence profile in order to facilitate thefabricationprocessofthefinalrestoration.Straight or angled conical abutments are now clearly visible on thevestibulo-lingualcross-sections.TenAnthogyrAX- IOM® PX implants were planned for a maxillary screw- retainedbridgerestoration(Figs.5a–c). _Implant placement Implant placement was performed under local anaesthesia using the case-specific surgical guide. For thispatient,Iusedaspecificimplantdesign(Axiom®PX) withsymmetricaldouble-leadthreads(self-drillingand self-tapping) and a reverse conical neck (Fig. 6). Its uniquedesigncombinedwithaspecialdrillingprotocol promotes bone condensation even in soft bone, which ensuresexcellentinitialfixation.TheBCP(biphasiccal- cium phosphate) sandblasting technique provides an implantsurfacewithsuperiorosteoconductiveproper- ties which positively influence the development of os- teoblastic cells in the early stage of osseointegration. A flapless technique was used for implant placement. The flapless technique has clear-cut advantages: preservationofthesubperiostealbloodvessels. _Temporary bridge and immediate loading It was agreed with the patient that the implants wouldbeimmediatelyloadedprovidedthatgoodinitial stabilitywasobtained.Thisway,thetemporaryremov- ableprosthesiswouldbewornforalimitedtime.Fortu- nately,adequatestabilitywasachieved,allowingforim- mediateloading.Eachimplant(exceptnumber27)was torquedto≥35Ncmormore.Thesameday,animpres- sionwasmadeusingthepick-uptechnique,withapre- viouslypreparedimpressiontray.First,thefinalstraight conical abutments were hand-tightened into the im- industry report I Figs. 2a–2c_Scan images. I 23implants1_2015 Fig. 2a Fig. 2b Fig. 2c