implants - international magazine of oral implantology

I research 10 I implants3_2012 ited space.28 Consequently, the indications for these implantswerelimitedandtheywerewithdrawnfrom the market. Morerecently,YSZhasbeenutilisedfordentalim- plants. This new generation of ceramic implants ex- hibits good mechanical properties, combined with good optical properties and high biocompatibility. In fact, YSZ has a flexural strength similar to titanium and a textural strength similar to stainless steel.29 A number of animal studies have demonstrated good osseointegration.30, 31 In further studies,32 the same authors have demonstrated osseointegration stability after a long-term loading period. Scarano33 analysed the bone–implant interface in rabbit tibia, andobservedneitherfibroustissuenorinflammation, with good bone-to-implant contact (68%). Similar results were obtained in monkeys by Kohal.34 Inanotherstudy,thesameauthorcomparedstress distribution in YSZ implants and titanium implants, and observed similar stress distribution patterns.35 Sennerby36 studied the effect of varying surface roughnessonextractiontorqueandbone-to-implant contact with YSZ implants compared with titanium implantssixweeksafterimplantinsertion.Theresults demonstrated that when surface roughness was en- hanced,thetwomaterialsexhibitedsimilarbehaviour. Other studies37, 38 have confirmed that a treated YSZ implantsurfaceprovidesgoodosseointegrationatall times and after a long-term loading period. These promising results led a still limited number of authors to test ZrO2 implants on humans. The first few clinical studies are quite recent. Among these, Blatsche and Voltz39 observed 98% osseointegration in 66 implants in 34 patients in a period of between twoandfiveyears.KohalandKlaus40 reportedthesta- bility of an YSZ implant in a fresh extraction socket with a graft material after loading. Oliva et al.41 re- portedone-yearresultsfor100YSZimplantswithtwo differentsurfaces,insomecasescombinedwithbone augmentation and sinus lift procedures. Within this observationperiod,theauthorsreporteda100%sur- vivalrateanda98%successrateintermsofabsence ofbleedingonprobing,signsofinflammation,mobil- ity and radiolucency. Similar results (93% success) were reported by Mellinghoff42 in a one-year follow- up study on 189 implants in 71 patients. These stud- ies suggest that YSZ implants exhibit a good rate of osseointegration. Improvements in zirconium surface characteris- tics will probably lead to interfacial biomechanical propertiescomparabletotreatedtitaniumsurfacesin thefuture.Comparedwithtitanium,plaqueadhesion to zirconium surfaces is very limited because no chemical or physical bonding between ZrO2 and plaqueoccurs.43 Thisisanimportantfeatureforlong- term survival. These findings, together with the good mechani- cal properties characteristic of zirconium implants, are encouraging. However, further histological and clinical studies are needed to investigate long-term success and stability. _Conclusion In conclusion, it can be stated that it is logical to use a ceramic material for the aesthetic regions. Zir- conium dioxide is particularly suitable, since it offers tissue friendliness and a resistance comparable to ti- tanium. Its increased tensile strength, superior me- chanicalproperties,unsurpassedintegrationwithtis- sue and aesthetic appearance, as well as the possibil- ity of easy fabrication of the prosthetic restoration, may well result in partially YSZ becoming the most commonlyusedmaterialinimplantdentistryforaes- thetic regions. This case report has demonstrated that YSZ im- plantsofferasuccessfulratecomparabletotitanium, with a higher aesthetic performance in the anterior region. For this reason, the authors recommend the utilisationofYSZimplantsincasesliketheoneinthis article._ Figs. 10 & 11_Periapical radiographs five years after surgery. Dr Virna Vavassori University of Milan Dental Clinic Postgraduate School of Oral Surgery Via della Commenda 10 20122 Milan Italy virna.vavassori@hotmail.it _contact implants Fig. 11Fig. 10