Long-Term Efficacy of Variable-Thread Tapered Implants—A Retrospective, Clinical and Radiological Evaluation

Abstract

Background and Objective: There is multifaceted evidence that variable-thread tapered implants (VTTIs) offer high primary stability but few regarding the long-term success. This retrospective clinical and radiological cohort study assessed the long-term outcome of VTTIs. Material and Methods: All patients treated in an OMFS practice with NobelActive Internal® VTTI between October 2007 and September 2011 were invited for clinical examination. The outcome variables were (i) survival rate, (ii) implant success according to the “Health Scale for Dental Implants” and (iii) prevalence of peri-implantitis. Furthermore, the effect of local and systemic risk factors was investigated. Results: In 81 subjects (46 females and 35 males, mean age 65.6 years) 270 implants (157 VTTIs and 113 others as a control group) were analyzed. In 7 out of 81 patients (8.6%), 8 out of 157 VTTIs (5.1%) and 5 out of 113 other implants (4.4%) were lost. Peri-implantitis, defined as (i) presence of bleeding on gentle probing (0.25 N) or exudation and (ii) radiographic bone loss exceeding 0.5 mm since implant insertion to last follow-up, was the most common reason for implant loss (11 out of 13, 84.6%). Sixty-six out of 87 VTTIs (75.9%) were successful. Seventeen out of 42 patients (40.5%) developed peri-implantitis on 29 out of 79 VTTI sites (36.7%). Plaque and missing keratinized peri-implant mucosa were identified as potential risk factors for the development of peri-implantitis. Conclusion: Variable-thread tapered implants showed good long-term results, even in low bone quality. Peri-implantitis was the most common reason for implant failure and may be connected to certain risk factors.

Risk factors associated with loss of variable‐thread tapered implants: A retrospective observational study of 1–5 years

“…The VTTIs have been broadly applied in clinical practice, particularly in anterior aesthetic areas, edentulous jaws, and poor bone quality regions. Some retrospective studies have confirmed its great clinical performance (Blume et al, 2020;Ho et al, 2013;Kielbassa et al, 2009), but the research for survival rates based on large population is infrequent. To the best of our knowledge, this is also the first study to report risk factors related to implant loss of VTTIs in such a sample.…”

“…Also, Takamoli et al (2021) found that over 80% of implant losses occurred after the connection of restorations through an 8.2-year retrospective study with 710 implants. Few studies evaluated the early and late survival rate of this VTTI system, and only two follow-up surveys found slightly high ratios in early implant loss (Blume et al, 2020;Saridakis et al, 2018). The sample was small in the above studies, thus, the proportional relationship TA B L E 2 Life table analysis of VTTIs at the implant and patient levels.…”

“…The variable‐thread tapered implants (VTTIs) could extend the indication of implant treatment due to their unique thread structure, particularly in cases of reduced bone quality (Blume et al, 2020; Ho et al, 2013; Irinakis & Wiebe, 2009). This implant system is designed with a tapered body and variable threads (deeper at the apical area) to increase self‐drilling ability and primary stability through condensing peri‐implant bone tissue during the insertion.…”

“…This implant system is designed with a tapered body and variable threads (deeper at the apical area) to increase self-drilling ability and primary stability through condensing peri-implant bone tissue during the insertion. Most studies exhibited the acceptable outcome of this implant system based on short-term follow-up (Babbush et al, 2013;Boon et al, 2020), and the implant survival rates could reach over 95% (Blume et al, 2020;Kielbassa et al, 2009;Kolinski et al, 2014). However, the sample size was relatively small in these studies (66-199 implants) and some literature revealed that the efficacy of the VTTI system after functional loading was not clear (Blume et al, 2020;Cristalli et al, 2015).…”

Surface attrition of zirconia and hybrid composite resin superstructure during implant therapy

“…Oral implants are widely used as a highly predictable prosthetic treatment for partially and fully edentulous patients, and in most cases successful long-term functional and esthetic outcomes can be expected [1][2][3][4][5]. Two types of complication can occur after implant treatment: biological and mechanical [6][7][8][9][10].…”