15-Year Retrospective Study on the Success Rate of Maxillary Sinus Augmentation and Implants: Influence of Bone Substitute Type, Presurgical Bone Height, and Membrane Perforation during Sinus Lift

Abstract

Objectives: To evaluate the success rate of bone grafts and implants carried out at the Latin American Institute for Research and Dental Education (ILAPEO), considering the following: (i) the different pure bone substitutes (autogenous, xenogeneic, and alloplastic), (ii) the presurgical bone height, and (iii) how the treatment is compromised when membrane perforation occurs during sinus lift in maxillary sinus surgeries. Material and Methods. The initial sample comprised 1040 records of maxillary sinus lifting surgeries. After evaluation, the final sample retained 472 grafts performed using the lateral window technique with a total of 757 implants. The grafts were divided into 3 groups: (i) autogenous bone (n = 197), (ii) xenogenous bovine bone (n = 182), and (iii) alloplastic material (n = 93). One calibrated examiner classified the sample into two groups based on the residual bone height (<4 mm and ≥4 mm) of the area of interest measured on parasagittal sections of tomographic images. Data on membrane perforation occurrences in each group were collected; qualitative variables were described using frequency, expressed as percentages. The Chi-square test was used to analyze the success of the graft types and the survival rate of the implants as a function of the grafted material and the residual bone height. The Kaplan-Meier survival analysis was used to calculate the survival rate of bone grafts and implants according to the classifications adopted in this retrospective study.

Results: The success rate of grafts and implants was 98.3% and 97.2%, respectively. There was no statistically significant difference in the success rate among the different bone substitutes (p = 0.140). Only 8 grafts (1.7%) and 21 implants (2.8%) failed. There was a greater success rate for both grafts (96.5%) and implants (97.4%) when the bone height was ≥4 mm. The success rate in the 49 sinuses in which the membrane was perforated was 97.96% for the grafts and 96.2% for the implants. The follow-up periods after rehabilitation ranged from 3 months to 13 years.

Conclusions: Within the limitations of the data analyzed in this retrospective study, maxillary sinus lift was a viable surgical technique that enabled implant placement with a predictable long-term success rate, regardless of the type of material used. The presence of membrane perforation did not interfere with the success rate obtained for grafts and implants.

Figure 1

Representative examples showing the measurement of residual bone height in the tomographic image: (a) <4 mm and (b) ≥4 mm.

Figure 2

Flowchart summarizing the sample selection methodology applied in this retrospective study.

Figure 3

The Kaplan-Meier survival analysis. (a) Survival rate according to bone graft materials over time. (b) Relation between bone graft materials and remaining bone height: <4 mm and ≥4 mm. (c) Relation between grafted bone sites and sinus membrane perforation.

Figure 4

The Kaplan-Meier survival analysis. (a) Survival rate of the implants in grafted bone sites: autogenous, xenogenic, and alloplastic. (b) Relation between implant survival rates and remaining bone height: <4 mm and ≥4 mm. (c) Relation between implant survival rates and sinus membrane perforation.

Figure 5

The Kaplan-Meier survival analysis. (a) Survival rate of the implants and type of surgical procedure: 1-stage and 2-stage. (b) Survival rate of the implants versus implant number per grafted bone site: 1 implant and 2 implants.