Sinus lift for implants in maxilla – graft or not?

Treatment of the atrophic maxillary ridge can be challenging as placement of dental implants requires peri-implant bone. A range of lateral and bone augmentation procedure are carried out and, in the maxilla, and these may be combined with elevation of the maxillary sinus membrane (sinus lifts). Graftless sinus lifts reporting high implant survival have also been reported.

The aim of this review was to assess the efficacy of graftless maxillary sinus membrane elevation using the lateral window approach for implantation in the atrophic maxilla.

Methods

Searches were conducted in the Cochrane Library, Embase and Medline/PubMed databases. Randomized controlled trials (RCTs) using the lateral window approach comparing grafted and graftless sinus membrane elevation in a minimum of 5 cases with a follow-up period of at least 6 months were considered. Both staged and simultaneous implantation were included. Study selection, data abstraction and risk of bias assessment using the Cochrane domains bases tool was undertaken. Outcomes included implant survival, vertical bone height gain, bone density, implant stability quotient (ISQ) and were expressed as the weighted mean difference (WMD) with the 95% confidence interval (CI).

Results

9 RCTs involving a total of 160 patients were included.
Allografts, xenografts, alloplasts, or a combination were used in 104 sinuses compared with no grafting and use of tenting technique in 112 maxillary sinuses.
6 studies were considered to be at low risk of bias and none at high risk.
Meta-analyses showed
- No difference between grafted and graftless groups Risk ratio (RR) = 0.99 (95%CI;0.79 to 1.25) [7 studies].
- A significant difference with less vertical bone height gain in the graftless group: mean difference = 1.73 mm (95%CI; 3.04 to 0.41 mm) [6 studies].
- Bone density to be significantly higher on the grafter side with a mean difference =94.7 Hounsfield units (HU) (95%CI; 134.9 to 54.5 HU) [4 studies].
- No significant difference in implant stability with the mean ISQ between the non-grafted and grafted sides, respectively 72.56 and 74.68 (2.12, 95% CI 4.40 to 0.15) [4 studies].

Conclusions

The authors concluded: –

this review and meta-analysis showed a high implant survival rate in non-grafted maxillary sinus lifts and conventional sinus lifts using augmentation materials (97.92% and 98.73%, respectively). The graftless sinus lift group showed a significantly lower vertical gain in bone height with a mean difference of 1.73 mm (P = 0.01) and a significantly lower bone density with a mean difference of 94.7 HU (P < 0.001). There was no significant difference in the ISQ values between the test and control groups (P = 0.07). The values in the test and control groups are considered to predict high implant survival for both procedures.

Comments

We have covered an earlier review of this topic by Yang et al (Dental Elf – 17^th May 2019) which included just 5 studies (only 2 of which appear in list new review) and demonstrated no difference between grafted and graftless augmentation. The authors of this new review have searched 3 major databases and also indicated had and grey literature searches were conducted although no details are presented. Only 9 small RCTs could be included with only one study having longer than 6 months follow-up. This review focuses on the lateral window approach and excludes studies using osteotome techniques so the findings may not be relevant to other approaches. The authors also highlight heterogeneity in the included studies with 3 studies using two-stage processes. While differences between the two techniques have been demonstrated there is the question of whether these differences are clinically important. Any future studies should follow SPIRIT and CONSORT guidelines and additional information on longer term outcomes and any adverse events would be beneficial.

Links

Primary Paper

Lie SAN, Claessen RMMA, Leung CAW, Merten HA, Kessler PAWH. Non-grafted versus grafted sinus lift procedures for implantation in the atrophic maxilla: a systematic review and meta-analysis of randomized controlled trials. Int J Oral Maxillofac Surg. 2021 Apr 10:S0901-5027(21)00126-0. doi: 10.1016/j.ijom.2021.03.016. Epub ahead of print. PMID: 33849784.

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