GP3b - Influence of Diameter on Survival Rates of Short and Ultra-Short Implants: A Systematic Review and Meta-Analysis

Presenting Author(s)

• 

  Chad Sindelar, DDS

  OMFS PGY3 resident
  Indiana University Oral and Maxillofacial Surgery
  Indianapolis, Indiana

  Handouts

Co-Author(s)

• 

  Waldemar D. Polido, DDS, MS, PhD

  Clinical Professor, Oral and Maxillofacial Surgery
  Indiana University School of Dentistry
  Indianapolis, Indiana
• LZ

  Leonardo Zanettini, DDS, MS, PhD

  Private Practice, Caxias do Sul, Brazil
  Visiting Scholar, Indiana University OMFS
  Caxias do Sul, Rio Grande do Sul, Brazil

Abstract:
Statement of the Problem: Short dental implants ( < 8 mm) are now widely used in reduced height ridges with high survival rates, especially in the posterior mandible. However, there is usually an assumption made by clinicians that shorter implants need to be wider. There are a limited number of studies that evaluate short and extra-short implants comparing implants length and width in clinical survival rates and predictability. The objective of this systematic review of the literature is to investigate the relation between implant width and length on the implant survival rate of short implants ( < 8 mm).
Material and

Methods: The reporting of this systematic review was based on the PRISMA Statement. The PICO question that needed to be answered is: Does implant diameter influences the survival rates for short dental implants? Two reviewers searched PubMed, Embase, Cochrane and Scopus were carried out, in addition to manual search and grey literature search in order to find those studies that were not published on journals indexed on the principal databases. Eligibility criteria was that the main topic reported on survival, success, failures, or complications using short implants. Both length and diameter had to be reported.
For each study included, the following information was extracted: authors, title, type of study, implant characteristics, surgical parameters, prosthetic characteristics, follow-up period, survival and failures rates. Risk of bias was performed independently by two independent authors utilizing the Newcastle-Ottawa Scale and the ROBINS-2 Tool. All of the data of the included studies were collated into tables showing the main characteristics and results of each study. To perform the meta-analysis, via a linear model of random effects, three groups were created: wide/extra-short implants; regular/extra-short implants and prosthesis type.
Results Twenty-four clinical studies from the 1962 articles initially identified met the inclusion criteria for the qualitative analysis. A total of 1.630 extra-short dental implants was included. The comparison between the relationship of diameter and length aimed to verify the failures rates in different types of short implants. The width was classified in 3 groups: Narrow (3.3–3.5 mm); Regular (3.75–4.5 mm) and Wide (4.8–6.5 mm). Each implant was correlated with each respective implant length and width group. On the narrow diameter implants group, a total of 68 implants with 6 mm length were analyzed. No failures were recorded. On the regular diameter implants group, 1.298 implants were recorded. A total of 50 failures were found. On the wide diameter implants group, 264 implants were analyzed.

Conclusions: Within the limitations of the current review, there is no evidence that a short or ultra-short implant has higher survival rates if it is of a wide diameter. In fact, with modern implant designs, the opposite may be true. Future studies with better control groups are necessary to bring stronger evidence to this concept.

References:
Griffin TJ, Cheung WS. The use of short, wide implants in posterior areas with reduced bone height: A retrospective investigation. J Prosthet Dent 2004;92:139-144.
Monje A, Jia-Hui F, Hsun-Liang C, Suarez F, Galindo-Moreno P, Catena A, Hom-Lay W. Do Implant Length and Width Matter for Short Dental Implants ( < 10 mm)? A Meta-Analysis of Prospective Studies. Periodontol 2013;84:1783-1791.
PRISMA flowchart of the screening process in the different databases Implant failures comparing length vs width