Please activate JavaScript!
Please install Adobe Flash Player, click here for download
ePaper created 2014-11-23, 21:56:20 | version 1.30.01
I research _The aim of this studywastoassesstheclinical andradiologicalperformanceofshort(6.5mm)im- plantsinsertedinthepremolarandmolarregionsof the maxillae. Eligible patients had to have a residual bone height of at least 6.5 mm and a bone width of at least 6.0 mm. Restoration was performed as sin- glecrownsorfixedlarge-spanbridgesandfollowed for up to two years after insertion. _Background The reconstruction of missing teeth in posterior regions is hampered by the limited bone availability and insufficient bone quality typically found in the posterior regions due to post-extraction bone atro- phy both apico-occlusally and bucco-palatally, a pneumatised sinus, etc. Significant functional forces in the posterior segments of the maxillae, among other factors, increase the risk of implant failure.1 Similar anatomical limitations are men- tioned in the recent review by Estafanous et al.2 Bonequality Restoration with implants in posterior regions is morecomplexif,forexample,permanentteethwere lost at young age, bone quality is poor (D3 and D4 according to Misch’s classification), or enhanced bone resorption due to mucous stimuli is present, and implant placement is complicated by the pres- ence of anatomic structures such as the sinus cav- ity or inferior alveolar nerve.3 Particularly in the maxillae, the use of short implants (i.e. the en- dosseous part is < 7 mm long) is advantageous to avoid sinus floor augmentation (sinus lift). Several bone augmentation techniques have beendevelopedwiththegoalofincreasingthebone volumebeforeimplantplacement,therebyallowing the use of longer and wider-diameter implants. The surgical problems and potential failures of such techniques have been clinically extensively docu- mented.4 Theplacementofshorterimplantshasthe potentialtoavoidtheneedforsuchtechniques.This wouldbebeneficialforpatientsbothintermsofre- duced morbidity and financially. Survivalrates Although early papers on short implants re- ported higher implant loss rates,5–8 recent system- atic literature reviews have found that initial sur- vival rates were comparable to that of longer im- plantsandthusconstituteaviablealternativetoad- ditional augmentation procedures. This correlates well with the fact that model calculations by finite element analysis indicate clearly that the distribu- tionofhorizontalandverticalloadingforcesissim- ilartothatoflongerimplants.9–12 Othercalculations have also demonstrated that bone stress should be almost independent of implant length; a more im- portantrolewasassignedtoimplantdiameter.6,13,14 Recent reports indicate that it is possible to achieve highly acceptable implant survival rates withthecurrentshortimplants.1,14 Stellingsmaetal. haveshownsurvivalratesof88–100%inatrophied mandibles.13 Asurvivalrateof96%wasreportedfor short implants in severely atrophic maxillae.15 Es- posito et al. compared the three-year post-loading outcomes of short and long (with guided bone re- Clinical and radiological performance of short implants A clinical study with two years follow up Authors_Dr Jean-Nicolas Hasson, Dr Jacques Hassid, Dr Dominique Aubazac, France & Paul Zeman PhD, Switzerland 06 I implants4_2014 [PICTURE: ©ALICE-PHOTO]