Discover the Latest Innovations and Success Rates in Short Dental Implants
Recent advancements in short dental implants have revolutionized the field.
Many of the current standards for implant success are based on these early implants. The first studies evaluating implant survival in partially edentulous patients showed a greater number of failures in shorter dental implants.1,2 Implants were later adapted to different clinical situations through changes in their design. For example, innovations in the implant-abutment connection support increased prosthetic success when used for single-tooth restorations. These include anti-rotational features and the internalization of the implant connection. While the external hex interface concentrates forces on the abutment screw, thereby increasing the incidence of screw loosening, internalization better distributes occlusal forces along the implant.3
Platform-switching or platform-shifting moves the microgap of the implant abutment connection further away from the oral environment, minimizing bone loss from harbored biofilms. A meta-analysis showed significantly less bone loss in platform-switched implants, if the difference in the implant-abutment diameter was ≥ 0.4 mm.4 Furthermore, a tapered implant body increases primary stability across all bone types and allows for placement in undercuts, narrow ridges or tight interdental spaces. Threads maximize initial bone-to-implant contact with decreasing pitch by enlarging the implant’s surface area. Microthreads and added texturing further dissipate coronal forces that can reduce crestal bone loss at the implant site.5
Implant surfaces can also be prepared or roughened through additive or subtractive techniques. Historically, hydroxyapatite coating and titanium plasma spraying were added. Today, the implant topography is “subtracted” by electropolishing or mechanical polishing, blasting or acid etching with different particles, and/or anodizing. Combinations of these techniques have led to greater surface roughness and marginal bone stability on the micro- and nanometer levels, as reported in a systematic review.6 Changes to the implant body or surface, however, do not compensate for all anatomical limitations, such as sinus pneumatization and ridge atrophy. Short dental implants offer a promising alternative for patients who cannot afford to undergo site development surgery for conventional implant placement.
APPLICATIONS FOR SHORT IMPLANTS
Because most loading forces are concentrated at the alveolar crest, implant length should have lesser effects on marginal bone and tissue stability. Short and extra short implants have shown minimal differences in survival over time. A systematic review of extra short implants noted a mean survival rate of 94.1%, with a maximum bone loss of 0.53 mm after five years.7
Shorter implants are advantageous in cases of sinus pneumatization. Patients with limited finances, sinus pathology, or moderate to severe obstructive sleep apnea requiring nighttime appliances may not be candidates for sinus augmentation procedures. In comparing extra short implants placed in native bone to 11- to 15-mm implants placed after sinus augmentation in the posterior maxilla, no significant differences in patient-level implant survival rates were reported (98.1% and 100%, respectively). There were also no significant differences in marginal bone loss, probing depths, and bleeding on probing after five years post-loading.8 In the atrophic maxilla or mandible, the cost, complication rate, and lack of predictability of vertical ridge augmentation may not be justified if placing a short implant is a viable option.9
This evidence supports fixed implant solutions to patients with anatomical restrictions. A recent meta-analysis demonstrated survival rates of 90% to 100% for fixed dental prostheses supported by extra short implants in the posterior mandible and maxilla.10 A potentially overlooked application of short implants is in the assistance of complete and partial removable dental prostheses in the severely resorbed residual ridge. This prosthetic design allows occlusal forces to be distributed and shared between the load-bearing areas of the residual ridge and surrounding surfaces. This type of load distribution leads to fewer implant and prosthetic complications when compared to short implants supporting a fixed prosthesis.11
References
- Ivanoff CJ, Gröndahl K, Sennerby L, Bergström C, Lekholm U. Influence of variations in implant diameters: a 3- to 5-year retrospective clinical report. Int J Oral Maxillofac Implants. 1999;14:173–180.
- Lekholm U, Gunne J, Henry P, et al. Survival of the Brånemark implant in partially edentulous jaws: a 10-year prospective multicenter study. Int J Oral Maxillofac Implants. 1999;14:639–645.
- Shafie HR, White BA. Different Implant-Abutment Connections. In: Clinical and Laboratory Manual of Dental Implant Abutments. Shafie HR, ed. Hoboken, NJ: Wiley-Blackwell; 2014:33–46.
- Atieh MA, Ibrahim HM, Atieh AH. Platform switching for marginal bone preservation around dental implants: a systematic review and meta-analysis. J Periodontol. 2010;81:1350–1366.
- Abuhussein H, Pagni G, Rebaudi A, Wang HL. The effect of thread pattern upon implant osseointegration. Clin Oral Implants Res. 2010;21:129–136.
- Wennerberg A, Albrektsson T. Effects of titanium surface topography on bone integration: a systematic review. Clin Oral Implants Res. 2009;20(Suppl 4):172–184.
- Ravidà A, Barootchi S, Askar H, Suárez-López del Amo F, Tavelli L, Wang HL. Long-term effectiveness of extra-short (≤ 6 mm) dental implants: a systematic review. Int J Oral Maxillofac Implants. 2019;34:68–84.
- Thoma DS, Haas R, Sporniak-Tutak K, Garcia A, Taylor TD, Hämmerle CH. Randomized controlled multicentre study comparing short dental implants (6 mm) versus longer dental implants (11–15 mm) in combination with sinus floor elevation procedures: 5-year data. J Clin Periodontol.2018;45:1465–1474.
- Esposito M, Grusovin MG, Coulthard P, Worthington HV. The efficacy of various bone augmentation procedures for dental implants: a Cochrane systematic review of randomized controlled clinical trials. Int J Oral Maxillofac Implants. 2006;21:696–710.
- Papaspyridakos P, De Souza A, Vazouras K, Gholami H, Pagni S, Weber HP. Survival rates of short dental implants (≤ 6 mm) compared with implants longer than 6 mm in posterior jaw areas: a meta-analysis. Clin Oral Impl Res.2018;29(Suppl 16):8–20.
- Omura AJ, Latthe V, Marin MM, Cagna DR. Implant-assisted removable partial dentures: practical considerations. Gen Dent.2016;64:38–45.
This information originally appeared in Botto AA, Saltz AE. Clinical utility of short dental implants. Decisions in Dentistry. 2021;7(6)36-39.