GP3d - Survival of Dental Implants Placed With Simultaneous Sinus Lift Procedure and Xenograft in a Central London Teaching Hospital

Abstract: Rehabilitation of the posterior maxilla with dental implants is frequently limited by insufficient alveolar bone height due to sinus pneumatization and anatomical constraints, posing a challenge for predictable osseointegration. Sinus floor elevation with simultaneous implant placement has been proposed as a single-stage solution; concerns remain regarding outcomes in cases with severely reduced residual bone height.

The aim of this retrospective study was to evaluate the long‑term survival of dental implants placed in the posterior maxilla with simultaneous sinus lift (SSL) procedure and xenograft augmentation. Specifically, the study aimed to find whether reduced residual bone height (RBH), defined as < 4 mm, adversely affects implant survival, and evaluate influential factors such as smoking status, history of radiotherapy, graft material used, and the presence of intraoperative sinus membrane perforation requiring repair.

This retrospective, single-center, observational cohort study was conducted including 55 patients who underwent the placement of 94 dental implants in the maxilla with SSL and xenograft placement. Data was taken from surgeries completed during the period of 2015 to 2024 in a tertiary oral surgery unit by single operator, Consultant Oral Surgeon, under general anesthesia.

Patient demographics, surgical variables, and implant characteristics were collected from electronic patient records and imaging, as summarized in Table 1-6. All patient data was anonymized prior to analysis.

The mean age at surgery was 30.8 ± 15.1 years. Most implants were placed for hypodontia (78%), predominantly in premolar region (83%). Implants placed were commonly Astra OsseoSpeedTM fixtures (78%), with implant diameter between 4 and 5 mm and commonly placed length 11 and 11.5 mm (68%).

Inclusion: Patients >17 years old receiving NHS funded dental implant placement with SLL procedure and xenografting in posterior maxilla were included.

Exclusion: Patients having 2-stage procedure, patients utilizing alternative grafting material, severely immunocompromised patients and patients with a history of bone modifying agents were excluded.

The overall cumulative survival rate was 97.9% for the 94 implants placed, with a mean survival time of 7.07 years (SD 3.22) and a mean follow‑up of 7.07 years (SD 3.26) (Table 7). Only 2 implant failures occurred during the study period. Survival rates were evaluated cumulatively at 5, 7, and 10 years according to residual bone height (RBH), comparing the < 4 mm and ≥ 4 mm groups (Table 8). These outcomes are consistent with previously reported high survival rates.^1,2

Statistical analysis using Fisher's exact test demonstrated no significant difference in survival outcomes between groups at any time point; 5 years (P = .49 ), 7 years (P = .62), and 10 years (P = .64). No statistically significant differences were found between smokers and non‑smokers (P = 1.00), implants placed in patients with or without prior radiotherapy (P = 1.00), graft material groups (P = 1.00), or implants placed with versus without membrane perforation (P = .346). The low failure rate limited statistical power and the ability to detect differences between subgroups.

Simultaneous sinus lift with xenograft augmentation was associated with high implant survival rates, even in sites with RBH ≤ 4 mm. These findings support this as a reliable single-stage technique that may reduce overall treatment time without compromising clinical success. Further studies with larger sample sizes are required to confirm these findings and evaluate the influence of patient and site-specific risk factors.


1. Pjetursson BE et al. 2008. Sinus floor elevation and implant survival: systematic review. J Clin Periodontol. 35(Suppl 8):216-40.

2. Sleman N, Khalil A. 2025. Simultaneous sinus augmentation with implant placement: systematic review. Open Dent J. 19.
The authors acknowledge that this research was undertaken during a two year Dental Foundation Training placement funded by NHS Workforce, Training and Education (WT&E), London Region.