Long-term Short Implants Performance: Systematic Review and Meta-Analysis of the Essential Assessment Parameters

Abstract

Lack of standard criteria in the outcome assessment makes it difficult to draw conclusions on the clinical performance of short implants and, under these circumstances, determine the reasons for implant failure. This study evaluated, through a systematic review of the literature and meta-analysis, the essential parameters required to assess the long-term clinical performance of short and extra-short implants. Electronic databases (Pubmed-MEDLINE, Cochrane Library Database, Embase, and Lilacs) were searched by two independent reviewers, without language limitation, to identify eligible papers. References from the selected articles were also reviewed. The review included clinical trials involving short dental implants placed in humans, published between January 2000 and March 2014, which described the parameters applied for outcome's measurements and provided data on survival rates. Thirteen methodologically acceptable studies were selected and 24 parameters were identified. The most frequent parameters assessed were the marginal bone loss and the cumulative implant survival rate, followed by implant failure rate and biological complications such as bleeding on probing and probing pocket depths. Only cumulative implant survival rate data allows meta-analysis revealing a positive effect size (from 0.052 (fixed) to 0.042 (random)), which means that short implant appears to be a successful treatment option. Mechanical complications and crown-to-implant (C/I) ratio measurement were also commonly described, however, considering the available evidence; no strong conclusions could be drawn since different methods were used to assess each parameter. By means of this literature review, a standard evaluation scheme is proposed, being helpful to regiment further investigations and comparisons on future studies.

Is there an effect of crown‐to‐implant ratio on implant treatment outcomes? A systematic review

“…Frequently, the crown-to-implant ratio increases not only for the greater interocclusal space but also for the reduced vertical dimension of the available bone and subsequent need for a short implant. Short endosseous implants from different implant brands have been reported in several reviews with high survival rates, as well in the maxilla as in the mandible (Annibali et al, 2012;Atieh, Zadeh, Stanford, & Cooper, 2012;Esfahrood et al, 2017;Fan, Li, Deng, Wu, & Zhang, 2017;Gonçalves et al, 2015;Kotsovilis, Fourmousis, Karoussis, & Bamia, 2009;Lemos, Ferro-Alves, Okamoto, Mendonça, & Pellizzer, 2016;Mezzomo, Miller, Trichet, Alonso, & Shinkai, 2014;Monje et al, 2013;Nisand, Picard, & Rocchietta, 2015;Pommer et al, 2011;Renouard, & Nisand, 2006;Srinivasan et al, 2014;Sun, Huang, Wu, & Shi, 2011;Telleman et al, 2011;Thoma, Cha, & Jung, 2017;Thoma, Zeltner, Hüsler, Hämmerle, & Jung, 2015). In the past years, implant lengths have continuously decreased.…”

Long‐term survival analysis of standard‐length and short implants with multifunctional abutments

“…Detailed case studies and treatment plans were made for all patients based on images, articulated cast models, and diagnostic wax‐ups. Data were gathered on patient age, sex, smoking habit, medical history (diabetes, heart disease, and osteoporosis), parafunction (self‐reported bruxism), implant length and region (maxilla/mandible), installation level (above, in, and below the alveolar crest), implant prosthesis material (metal‐ceramic, zirconia, and acrylic resin), type of antagonist (natural tooth, metal‐ceramic crown, and acrylic resin prosthesis), loading protocol (immediate and conventional), implant features, and study withdrawal …”

Evaluation of Strain Developed Around Short Dental Implants Using Two Different Restorative Materials (In Vitrostudy)

“…The anatomical C/I ratio offers a more favorable biomechanical scenario, as the lever arm is shorter than in the clinical C/I ratio. However, the clinical C/I ratio offers a more realistic clinical scenario, as the connection of the implant restoration at the implant shoulder is more rigid than at the implant-bone interface due to bone viscoelasticity (14).…”