Osseointegrated dental implants have been available since the late 1970s, initial placement protocols recommended an initial load free healing period. Improved understanding of osseointegration has lead to the use of immediate or early loading protocols. The aim of this study was to compare the feasibility of loading four implants with a pre-existing denture converted to a fixed dental prosthesis (FDP) on the day of implant surgery compared with waiting for 3- to 4-month healing.
Patients with good oral hygiene over the age of 18 who had been edentulous for at least 3 months or at least 6 months after any bone grafting were included. A single operator carried out all surgical procedures, following manufacturers guidelines. Patients were randomised to immediate or delayed loading. Patients in the immediate group had their denture converted into an implant-supported FDP on the day of surgery. For both groups, the permanent 10- to 12-unit FDP consisting of a type-3 cast precious alloy veneered with acrylic and artificial teeth was placed 3–4 months after implant surgery. The primary outcome of interest was the crestal bone level changes at different time points, as measured on the standardized periapical radiographs. Patients were recalled at 6 months and then annually.
- 42 patients were randomised. 5 patients in the immediate group did not receive the intervention but remained in the study.
- 18 patients in the delayed and 17 patients in the immediate group were seen at the 5-year review. Only 13 of those in the immediate group received the intervention as randomised.
- 3 implants failed to osseointegrate in the immediate arm, compared with one implant in the delayed arm.
- Crestal bone level changes over 5 years were identical in the experimental and control groups, that is, 1.2 mm (SD = 0.7).
- There were no differences between the two study arms with regard to incidence of biological and technical adverse events. The most common adverse events were surface fractures of the FDPs and bleeding on probing.
The authors concluded
Same day loading of implants in the anterior mandible to retain a full-arch FDP converted from a pre-existing optimal denture compared with waiting for 3–4 months before loading seems to yield comparable outcomes after 5-year observation.
Study Funding:- Nobel Biocare Services AG, Kloten, Switzerland (Grant Number 2006-443).
This study is well reported and provides good detail regarding the clinical and technical procedures. It is also very clear about what happened to the 5 patients allocated to the immediate group who did not receive the intended treatment. The main focus of the analysis is based on a per protocol analysis rather than an intention to treat approach and this is discussed by the authors. A Cochrane review (Espositio et al) updated earlier this year has also looked at different loading time for implants and noted that:-
Overall there was no convincing evidence of a clinically important difference in prosthesis failure, implant failure, or bone loss associated with different loading times of implants.
In the discussion the Cochrane reviewer went to say
Although this review has included 26 RCTs, the low failure rate of both implants and prostheses in these trials means that there is still insufficient evidence to support definitive conclusions. However, research suggests that thousands of participants would need to be included in randomised trials in order to produce conclusive evidence
Jokstad A, Alkumru H. Immediate function on the day of surgery compared with a delayed implant loading process in the mandible: a randomized clinical trial over 5 years. Clin Oral Implants Res. 2013 Oct 23. doi: 10.1111/clr.12279. [Epub ahead of print] PubMed PMID: 24148020.
Esposito M, Grusovin MG, Maghaireh H, Worthington HV. Interventions for replacing missing teeth: different times for loading dental implants. Cochrane Database of Systematic Reviews 2013, Issue 3. Art. No.: CD003878. DOI: 10.1002/14651858.CD003878.pub5.