Extra short dental implants supporting an overdenture in the edentulous maxilla: A proof of concept
Department of Periodontology, Faculty of Medicine, Catholic University Leuven, Leuven, Belgium. Clinical Oral Implants Research
(Impact Factor: 3.89).
07/2011; 23(5):567-76. DOI: 10.1111/j.1600-0501.2011.02235.x
This study investigates the outcome of short implants additionally placed with longer implants to support a maxillary overdenture.
Twelve patients received six implants to support a maxillary overdenture. Only one patient still had two molars in the maxilla, while the others had no remaining teeth. The status of the opposing arch was diverse. The distal implant in each quadrant was 6 mm in height (S) and the middle implants ranged between 10 and 14 mm (L). All implants were placed following a one-stage procedure and early loaded (6 weeks). Clinical and radiological parameters were assessed 6, 12 and 24 months after loading.
One short implant failed 2 weeks after surgery, probably due to early mobilization by the provisional prosthesis. The mean bone loss on the rough part of the implant was 0.7 mm (S) vs. 1.3 mm (L) during the first year and 0.3 mm (S) vs. 0.2 mm (L) during the second year after loading. The mean implant stability quotient values were 67 (S) vs. 70 (L) at placement and 75 (S) vs. 78 (L) after 1 year. At the 2-year follow- up, all prostheses were still stable and comfortable.
An overdenture on six implants, of which two have a reduced length, might represent a successful treatment option. No significant difference could be found between both implant lengths at 2 years' follow-up. However, bone loss with short implants may increase the likelihood of failure.
Available from: Istabrak Hasan
- "More recent studies, however, suggest that short implants (7 to < 10 mm) can reach similar success rates as longer ones for the support of fixed partial dental prostheses    . Even 1-year  and 7-year  follow-up studies report that short implants (8 – 9 mm long)    are not less successful compared with implants > 10 mm long in the posterior region with fixed partial dental prostheses. "
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ABSTRACT: The use of short implants has increased widely within the last years. However, the stability of these implants has not yet been comprehensively investigated, in particular the difference in geometry and dimension of short implants. The aim of the present study was to investigate experimentally the difference of the secondary stability of different commercial short implants by measuring their displacements. Eleven implant geometries were investigated in this study. A total of 22 implants were inserted in porcine rib segments, two implants for each system. Implant displacements were measured using a self-developed biomechanical hexapod measurement system (HexMeS). The highest displacement was observed with Straumann BL NC 3.3×8.0 mm (266 μm), followed by Straumann Standard 4.1×6.0 mm (156 μm), while the lowest displacement of 61 μm was shown by Dentaurum type 1 implant (4.2×5.0 mm). No obvious difference of displacements was observed between hammered and screw-shaped implants with relevant dimensions. The experimental results were in good agreement with the numerical ones (19–42%) for Dentaurum implants. However, a difference of 70–80% was obtained for the Astra implant (4.0×6.0 mm) and Bicon implant (6.0×5.7 mm). The geometry of short implants directly affects their stability within the bone.
Available from: Friedhelm Heinemann
- "More recent studies, however, suggested that short implants (7 to <10 mm) can reach similar success rates as longer ones for the support of fixed partial dental prostheses   . Even 3-year  and 7-year  followup studies reported retrospectively that short implants (8 to 9 mm long)    were not less successful compared with implants >10 mm long in the posterior region with fixed partial dental prostheses. This paper was aimed to review the works regarding the stability and survival rate of short implants under functional loads. "
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ABSTRACT: This paper was aimed to review the studies published about short dental implants. In the focus were the works that investigated the effect of biting forces of the rate of marginal bone resorption around short implants and their survival rates. Bone deformation defined by strain was obviously higher around short implants than the conventional ones. The clinical outcomes of 6 mm short implants after 2 years showed a survival rate of 94% to 95% and lower survival rate (<80%) for 7 mm short implants after 3 to 6 years for single crown restorations. The short implants used for supporting fixed partial prostheses had a survival rate of 98.9%. Short implants can be considered as a good alternative implant therapy to support single crown or partial fixed restorations.
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The purpose of this prospective study was to investigate the clinical success of a treatment protocol for the rehabilitation of edentulous posterior maxilla consisting of the positioning of short implants in combination with transcrestal sinus lifting, with the adjunct of pure (leukocyte-free) platelet-rich plasma, in order to reducing the risk of membrane perforation and other surgical complications.
Materials and methods:
A total of 25 patients (65 implants) were treated. Pure platelet-rich plasma was used in the sinus membrane lifting procedure. Implants of 8.5 mm length or shorter were splinted through the prosthetic rehabilitation with one or more implants longer than 10 mm.
After a follow-up period ranging from 12 to 19 months (mean 14.4 months) after prosthetic loading, 23 patients (60 implants) were evaluated. Overall implant success and survival rates were 100% at 1 year follow-up visit. All prosthetic rehabilitations were successful and in function. After 1 year of loading, peri-implant bone loss averaged 0.34 ± 0.21 mm for 8.5 mm or shorter implants (n = 25) and 0.36 ± 0.30 mm for longer implants (n = 35) (overall mean 0.35 ± 0.25 mm) without significant difference between the two groups (p = 0.23).
The proposed treatment protocol is a viable option for the rehabilitation of edentulous posterior atrophic maxilla.
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