While the use of dental implants has becomes common sufficient bone volume is required fro their placement. A range of reconstructive procedures including guided bone regeneration, onlay or inter-positional grafts, raising of the floor of the maxillary sinus, distraction osteogenesis, transposition of the alveolar nerve, and the use of shorter implants have been used where sufficient bone is not available.

The aim of this review was to compare the use of longer implants with augmentation of the alveolar ridge or shorter implants in native bone in patients with atrophic jaws.

Methods

Searches were conducted in the PubMed, Embase and the Cochrane Central Register of Controlled Trials (CENTRAL) databases supplemented with manual searches of the journals; British Journal of Oral and Maxillofacial Surgery, Clinical Implant Dentistry and Related Research, Clinical Oral Implants Research, European Journal of Oral Implantology, Implant Dentistry, Journal of Oral Implantology, Journal of Oral and Maxillofacial Surgery, Journal of Dental Research, Journal of Clinical Periodontology, Journal of Periodontology, International Journal of Prosthodontics, International Journal of Oral and Maxillofacial Surgery, International Journal of Oral and Maxillofacial Implants, and the International Journal of Periodontics and Restorative Dentistry.

Randomised controlled trials (RCTs) published in English with a minimum of 10 patients and minimum follow up of 1 year were considered. Study quality was assessed by two reviewers independently using the Cochrane Risk of bias tool with overall quality being assessed using the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE).

Results

• 6 studies involving a total of 837 implants in 335 patients were included.
• There were 167 patients (429 implants) in the augmentation group and 168 patients (408 implants) in the shorter implants group.
• Follow-up period ranged from 1-10 years.
• 5 studies were considered to be at low risk of bias and 1 at high risk.
• There were significantly more failed implants in the augmentation group than the shorter implants group, relative risk (RR) = 3.34 (95%CI; 1.41 to 7.9), p = 0.006.
• There were also significantly more complications in the augmentation group, RR= 3.03 (95%CI; 1.28 to 7.17), p = 0.01.
• Marginal bone loss was also significantly greater in the augmentation group , Mean difference = 0.07 ( 95%CI; 0.03 to 0.11), p = 0.0004.
• According to the GRADE approach, the levels of evidence were moderate (failure of implants) and high (complications).

Conclusions

The authors concluded:

Current evidence suggests that shorter implants might be a better alternative to augmentation of the alveolar ridge in atrophic jaws in which there is enough space to place shorter implants without augmentation.

Comments

This review has included 6 English language publications with the findings suggesting that short implants provide better outcomes. Three of the included studies considered implants in both the mandible and maxilla while the other three were restricted to the mandible. The authors note heterogeneity between the studies in terms of different types of grafts in different sites, different types of augmentation, varying follow-up times, and varying characteristics of short implants, which need to be considered while assessing the findings.

Last year ( Dental Elf- 22^nd May 2014) we considered the Cochrane review of sinus lift augmentation versus short implants. That review included 18 RCTs involving 650 patients and concluded:-

There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 8.5 mm) in reducing prosthesis or implant failure up to one year after loading. However, there are more complications at sites treated with sinus lift procedures.

Links

Primary paper

Yang J, Cheng Z, Shi B. Augmentation of the alveolar ridge compared with shorter implants in atrophic jaws: a meta-analysis based on randomised controlled trials. Br J Oral Maxillofac Surg. 2015 Nov 3. pii: S0266-4356(15)00640-3. doi: 10.1016/j.bjoms.2015.10.011. [Epub ahead of print] PubMed PMID: 26545348.

Other references

Original review protocol on PROSPERO database

Dental Elf- 22^nd May 2014 – Available evidence is insufficient to show if sinus lift techniques or short implants are more effective in reducing failures of dental prostheses