Polizzi Giovanni
Published: 2017
Total Pages:
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BackgroundVariable-thread tapered implants are designed to achieve high primary stability in demanding situations, such as fresh extraction sitesor regions of low bone quality. In addition to their specialized thread design, these implants can be placed at torques up to 70 Ncm.Continued investigation of these implants placed in challenging situations is necessary to evaluate their long-term survival and clinicalperformance.Aim/HypothesisThe main objective of this retrospective analysis was to evaluate the bone remodeling as a measure of safety and efficacy in patientindications with single crowns or partial bridges restored on variable-thread tapered implants after up to 6.7 years of function.Materials and MethodsPatients with single or partial tooth restorations, who received at least one variable-thread tapered implant (NobelActive, NobelBiocare) between January 2008 and July 2009 were retrospectively evaluated. Bone quality was assessed (Lekholm and Zarb (1985))at time of surgery. Marginal bone levels (MBL) were measured from radiographs at baseline (implant insertion), at 1-year follow-up,and at last follow-up (mean 6.0 years, range 4.7 - 6.7 years). Marginal bone remodelling (MBR) was calculated for paired radiographsfrom baseline to 1-year follow-up, baseline to 6-year follow-up, and from 1-year to 6-year follow-up. Secondary measures reportedinclude presence of plaque, Jemtu2019s papilla index, and implant stability. Statistical analysis was performed with the software SPSSStatistics 24 (IBM, Armonk, NY, USA).ResultsTwenty-four patients (14 female, 10 male; mean age 58 u00b19.9 years) received 35 implants. 94% of implants were placed in the maxilla(n=33). 20 implants were placed in extraction sockets and 15 in healed sites. 32 implants were tightened to torques >35 Ncm (mean59.6 u00b113.2 Ncm). Bone quality was reported as 2 (n=9), 3 (n=18), and 4 (n=8). Graft material was used at time of implant insertion for9 of the 20 extraction sites. Sinus lift was performed in 3 implant sites. All patients received an acrylic provisional prosthetic and 23received final prosthetics at a mean of 1.5 years after implant insertion. Mean MBL were -0.54 u00b10.62 mm, -1.04 mm u00b10.68 mm, and-1.04 u00b10.98 mm at baseline, 1-year follow-up, and 6-year follow-up, respectively. Mean MBR was -0.47 u00b10.64 mm, -0.38 u00b11.22 mm,and -0.11 u00b11.01 mm from baseline to 1-year, baseline to 6-years and 1-year to 6-years, respectively. No adverse events werereported and all implants were stable at final follow-up.Conclusions and Clinical implicationsThis 6-year retrospective analysis showed that variable-thread tapered implants show good long-term outcomes, in terms of survival,stability and MBR, when placed in demanding situations such as extraction sockets or low density bone sites (i.e. in the maxillaryposterior area). Additionally, high insertion torques (>35 Ncm) could be achieved with this protocol with only minor MBR from baselineto 1-year follow-up and stable bone levels from 1-year to up to 6 years of function.