4.5 and 5.5 mm Reduced-Diameter Implants with Immediate Loading in Vertical Atrophies
A Minimally Invasive Alternative to Bone Regeneration (Retrospective Study)
DOI:
https://doi.org/10.29166/od.v28i1.9247Keywords:
extra-short implant, immediate loading, severe bone atrophy, biological drilling, primary stability, oral rehabilitationAbstract
Objective: To evaluate the mid-term clinical and radiographic outcomes of 4.5 mm and 5.5 mm extra-short implants with narrow platforms and reduced diameters, placed in patients with severe vertical bone atrophy and restored through immediate loading as a minimally invasive alternative to bone regeneration. Materials and methods: A retrospective study was conducted in 8 patients treated between December 2019 and February 2021, with a total of 27 extra-short implants. Planning was performed using CBCT and specific software. Implant bed preparation followed a biologic drilling protocol adapted to bone density. All implants were restored with splinted screw-retained prostheses under immediate loading. Surgical and prosthetic complications, insertion torque, implant and prosthetic survival, and mesial and distal marginal bone loss were recorded. Statistical analysis was performed using SPSS v15.0 (p<0.05). Results: All 27 implants remained functional during a mean follow-up of 21.32 ± 6.90 months, achieving a survival rate of 100 %. Mean insertion torque was 30.74 ± 16.09 Ncm and showed a direct relationship with bone density. No complications were observed during immediate loading or definitive rehabilitation. Marginal bone loss was low: 0.36 ± 0.28 mm mesially and 0.46 ± 0.30 mm distally. Conclusions: The extra-short implants evaluated represent a predictable and minimally invasive alternative for severe vertical atrophy. The stability observed supports their use when individualized surgical and prosthetic planning is performed in anatomically compromised posterior regions where conventional implant placement may be limited or contraindicated. However, prospective studies with larger samples and longer follow-up periods are required to confirm these findings.
Downloads
References
1. Esposito M, Felice P, Worthington HV. Interventions for replacing missing teeth: augmentation procedures of the maxillary sinus. Cochrane Database Syst Rev. 2014;2014(5):CD008397.
2. Rocchietta I, Fontana F, Simion M. Clinical outcomes of vertical bone augmentation to enable dental implant placement: a systematic review. J Clin Periodontol. 2008;35(8 Suppl):203-215.
3. Urban IA, Monje A, Lozada JL, Wang HL. Long-term evaluation of guided bone regeneration for vertical bone augmentation: a 20-year prospective case series study. Int J Periodontics Restorative Dent. 2019;39(3):381-390.
4. Sanz-Sánchez I, Sanz-Martín I, Ortiz-Vigón A, Molina A, Sanz M. Complications in bone-grafting procedures: Classification and management. Periodontol 2000. 2022 Feb;88(1):86-102.
5. Pommer B, Mailath-Pokorny G, Haas R, Buseniechner D, Millesi W, Fürhauser R. Extra-short (< 7 mm) and extra-narrow diameter (< 3.5 mm) implants: a meta-analytic literature review. Eur J Oral Implantol. 2018;11 Suppl 1:S137-S146.
6. Calvo-Guirado JL, López Torres JA, Dard M, Javed F, Pérez-Albacete Martínez C, Maté Sánchez de Val JE. Evaluation of extrashort 4-mm implants in mandibular edentulous patients with reduced bone height in comparison with standard implants: a 12-month results. Clin Oral Implants Res. 2016 Jul;27(7):867-874.
7. Gonçalves TM, Bortolini S, Martinolli M, Alfenas BF, Peruzzo DC, Natali A, Berzaghi A, Garcia RC. Long-term Short Implants Performance: Systematic Review and Meta-Analysis of the Essential Assessment Parameters. Braz Dent J. 2015 Jul-Aug;26(4):325-36.
8. Kovacic I, Persic S, Kranjcic J, Lesic N, Celebic A. Rehabilitation of an Extremely Resorbed Edentulous Mandible by Short and Narrow Dental Implants. Case Rep Dent. 2018 Dec 20;2018:7597851.
9. Ruiz JL. An evidence-based concept of implant dentistry. Utilization of short and narrow platform implants. Dent Today. 2012 Sep;31(9):94, 96-9.
10. Esposito M, Grusovin MG, Achille H, Coulthard P, Worthington HV. Interventions for replacing missing teeth: different times for loading dental implants. Cochrane Database Syst Rev. 2013;2013(3):CD003878.
11. Gallucci GO, Hamilton A, Zhou W, Buser D, Chen S, Chen Z. Implant loading protocols for partially edentulous patients with fixed prostheses: a systematic review. Clin Oral Implants Res. 2014;25(4):437-452.
12. Kulkarni V, Uttamani JR, Asar NV, Nares S, Tözüm TF. Evidence-Based Clinical Outcomes of Immediate and Early Loading of Short Endosseous Dental Implants: A Meta-analysis. Int J Oral Maxillofac Implants. 2021 Jan-Feb;36(1):59-67.
13. Hong DGK, Oh JH. Recent advances in dental implants. Maxillofac Plast Reconstr Surg. 2017 Nov 5;39(1):33.
14. Amato F, Polara G, Spedicato GA. Immediate Loading of Fixed Partial Dental Prostheses on Extra-Short and Short Implants in Patients with Severe Atrophy of the Posterior Maxilla or Mandible: An Up-to-4-year Clinical Study. Int J Oral Maxillofac Implants. 2020 May/Jun;35(3):607-615.
15. Weerapong K, Sirimongkolwattana S, Sastraruji T, Khongkhunthian P. Comparative study of immediate loading on short dental implants and conventional dental implants in the posterior mandible: A randomized clinical trial. Int J Oral Maxillofac Implants. 2019 January/February;34(1):141–149.
16. Anitua E. Immediate Loading of Short Implants in Posterior Maxillae: Case Series. Acta Stomatol Croat. 2017 Jun;51(2):157-162.
17. Hadilou M, Ebrahimi P, Karimzadeh B, Ghaffary A, Gholami L, Fathifar Z. Immediate loading of short implants: A systematic review. J Adv Periodontol Implant Dent. 2021 Mar 6;13(1):15-21.
18. Galletti F, Galletti C, Gonzalez Terrats R, D'Amico C, De Angelis F, Cervino G, Fiorillo L. Immediate versus conventional loading in short and ultra-short implants: a protocol design. Minerva Dent Oral Sci. 2025 Feb;74(1):49-65.
19. Poulopoulos G, Mirzakhanian C, Heydecke G, Esken J, Reissmann DR. Primary and Secondary Stability of Short (4 mm) Versus Standard (≥ 10 mm) Implants Placed in the Same Mandible: A Prospective Clinical Study. Int J Oral Maxillofac Implants. 2023 Jul-Aug;38(4):733-738.
20. Norton MR. The Influence of Low Insertion Torque on Primary Stability, Implant Survival, and Maintenance of Marginal Bone Levels: A Closed-Cohort Prospective Study. Int J Oral Maxillofac Implants. 2017 Jul/Aug;32(4):849-857.
21. Anitua E, Alkhraisat MH, Piñas L, Orive G. Efficacy of biologically guided implant site preparation to obtain adequate primary implant stability. Ann Anat. 2015 May;199:9-15.
22. Anitua E, Escuer V, Alkhraisat MH. Short Narrow Dental Implants versus Long Narrow Dental Implants in Fixed Prostheses: A Prospective Clinical Study. Dent J (Basel). 2022 Mar 4;10(3):39.
23. Anitua E, Eguia A, Alkhraisat MH. Extra-short implants (≤ 6.5 mm in length) in atrophic and non-atrophic sites to support screw-retained full-arch restoration: a retrospective clinical study. Int J Implant Dent. 2023 Sep 13;9(1):29.
24. Anitua E, Eguia A, Alkhraisat MH. Clinical Performance of Splinted 4.5-mm Extra-Short Implants: A Controlled Retrospective Cohort Study. Int J Periodontics Restorative Dent. 2024;44(5):544-555.
25. Anitua E. Implante de 5,5 mm. Una solución para atrofias severas sin renunciar a la predictibilidad [5.5 mm implant. A solution for severe atrophies without sacrificing predictability]. Rev Cient Odontol (Lima). 2023 Dec 26;10(4):e137.
26. Anitua E, Carda C, Andia I. A novel drilling procedure and subsequent bone autograft preparation: a technical note. Int J Oral Maxillofac Implants. 2007 Jan-Feb;22(1):138-45.
27. Misch CE, Perel ML, Wang HL, et al. Implant success, survival, and failure: The International Congress of Oral Implantologists (ICOI) Pisa Consensus Conference. Implant Dent. 2008;17(1):5–15. doi:10.1097/ID.0b013e3181676059
28. Albrektsson T, Zarb G, Worthington P, Eriksson AR. The long-term efficacy of currently used dental implants: A review and proposed criteria of success. Int J Oral Maxillofac Implants. 1986;1(1):11–25.
29. Papaspyridakos P, Chen CJ, Chuang SK, Weber HP, Gallucci GO. A systematic review of biologic and technical complications with fixed implant rehabilitations for edentulous patients. Int J Oral Maxillofac Implants. 2012;27(1):102–110.
30. McGrath C, Lam O, Lang N. An evidence-based review of patient-reported outcome measures in dental implant research among dentate subjects. J Clin Periodontol. 2012 Feb;39 Suppl 12:193-201.
31. Gurgel BC, Pascoal AL, Souza BL, Dantas PM, Montenegro SC, Oliveira AG, Calderon Pdos S. Patient satisfaction concerning implant-supported prostheses: an observational study. Braz Oral Res. 2015;29:S1806-83242015000100235.
32. Maló PS, de Araújo Nobre MA, Lopes AV, Ferro AS. Retrospective cohort clinical investigation of a dental implant with a narrow diameter and short length for the partial rehabilitation of extremely atrophic jaws. J Oral Sci. 2017;59(3):357-363.
33. Annibali S, Cristalli MP, Dell'Aquila D, Bignozzi I, La Monaca G, Pilloni A.
Short dental implants: a systematic review. J Dent Res. 2012;91:25-32.
34. 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 Implants Res. 2018;29 Suppl 16:8-20.
35. Fernandes G, Costa B, Trindade HF, Castilho RM, Fernandes J. Comparative analysis between extra-short implants (≤6 mm) and 6 mm-longer implants: a meta-analysis of randomized controlled trial. Aust Dent J. 2022 Sep;67(3):194-211
36. Zhang Q, Gong J, Yu J, Zhao R, Gou P, Yu Z. Clinical efficacy of extra-short implant (4 mm) placed in posterior areas: a Meta-analysis. Hua Xi Kou Qiang Yi Xue Za Zhi. 2023 Feb 1;41(1):80-87.
37. Anitua E, Montalvillo A, Eguia A, Alkhraisat MH. Clinical performance of extra-short (≤5.5 mm) compared to longer implants splinted under the same prosthesis: a randomized clinical trial. Dent J (Basel). 2024;12(9):292.
Published
How to Cite
Issue
Section
License
Copyright (c) 2026 Eduardo Anitua
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
