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ePaper created 2015-03-04, 10:43:31 | version 1.33.01
I research 20 I implants1_2015 astrongsofttissuecollar.Theinternalconnectioncon- sists of a machine taper (11°) and a hexagonal index. The implant shows a fairly homogenous roughness over the entire surface with a Sa-value ranging from 2.0to2.3µm.ThecorrespondingRa-valuesvaryfrom 1.3 to 2.5 µm. This means that this implant falls just within the category of moderately rough implants. A total of 393 GC Aadva implants were placed. Their intra-oral distribution is summarised in table 1. The implants were primarily placed in the upper jaw (248implants,63.1%)andofteninthepremolararea (120 implants, 30.5%) or the molar area (157 im- plants, 39.9%). The diameter of most implants was 4mm(n=284),butnarrow(n=69)andwideimplants (n=40) were used as well. Several implant lengths wereused:8mm(57),10mm(144),12mm(160)and 14mm(32).Mostimplantswereplacedinbonequal- ity type 2 (79.9%), while 10.4% were placed in type 1 bone and 9.7% were placed in type 3 bone.23 Severalpatientspresentedriskfactors:10%ofthe patients were smokers; bone dehiscence occurred in 12.9% and pre-operative guided bone regeneration was necessary at 6% of the sites. A sinus floor eleva- tion was required in 11% of the cases, and 11.5% of the implants had only limited primary stability at the time of placement. A total of 5 implants were lost. These losses were probably due to an excess of clini- cal indications in order to push the capabilities of the implant Aadva. A Kaplan-Meier analysis (Tab. 2) showed a 98.5% cumulative success rate for the im- plants after 42 months. For 334 implants (118 pa- tients) the marginal bone loss could be followed lon- gitudinally (Tab. 3). The cross-sectional data (not al- ways with the same implants at any given time) re- vealed a 0.2 mm bone loss between placement and loading, 0.2 and 0.4 mm during the first and second years, and no further loss afterwards. The longitudi- nal analyses (with the same implant observed at sev- eralpointsintime)showeda0.3mmrelativeboneloss during the first and second year of loading, with an unchanged situation afterwards (Fig. 2). The number ofimplantswithmorethan1mmbonelosswas5.5% during the first year and 8.8% during the first two years. _Discussion Initial bone remodelling after implant placement and loading is presently a focus of industrial compe- tition. Some companies advertise their implant as having minimal bone loss during this period of re- modelling. With some implant designs, connections andtopographies,bonelevelwassometimesreported tobeaslowasthefirstorsecondmacro-threadinthe first months after loading. The data of this study showed a 0.4 mm average bonelossduringthehealingperiod,whichissimilar to the best performing implants currently on the market.Theseobservationscontrastwithstudieson otherimplantdesignsthatreportmuchhigherbone losses during this period.24,25 Bone level appears to subsequently remain relatively stable with an aver- age loss of 0.3 mm during the first and second year. Afterwards it was found that this bone resorption could be further reduced. It should nevertheless be pointed out that this paper reports on a field study,farawayfromtheacademicenvironmentbut Fig. 3i_Contained tooth gap treated with 2 Aadva implants; 2 years follow-up. Fig. 3j_Posterior tooth gap treated with 3 Aadva implants; 3 years follow-up. Fig. 3k_Posterior tooth gap treated with 3 Aadva implants; 4 years follow-up. Fig. 3l_Posterior tooth gap treated with 3 Aadva implants; 5 years follow-up. Fig. 3i Fig. 3j Fig. 3k Fig. 3l