Influence of implant protrusion length on non-grafting osteotome sinus floor elevation with simultaneous implant: a 3- to 9-year retrospective study

Abstract

Background This study analyzed the influence of implant protrusion length (IPL) on the possible factors that affect the long-term outcomes utilizing non-grafting osteotome sinus floor elevation (OSFE) with simultaneous implant placement, and to explore the optimal range of IPL. Materials and methods A retrospective study design was adopted. The clinical and radiographic data of 105 implants in 65 patients were collected after 3–9 (mean 5.04) years follow-up. IPL was divided into three groups (group1, IPL<2mm; group2, 2mm≤IPL<4mm; group3, IPL≥4mm). Endo-sinus bone gain (ESBG), peri-implant marginal bone loss (MBL), bone to implant contact length (BICL), and percentage of ESBG (%ESBG) were used to evaluate non-grafting OSFE. A Kaplan-Meier analysis was performed to assess the cumulative survival rate. Multiple linear regression model was used to explore the relationship between the possible influence factors and ESBG. Analysis of variance (ANOVA) was applied to explore the correlation of IPL with ESBG, MBL, BICL, and %ESBG. Results A total of 102 implants in 62 patients fulfilled the survival criteria, giving the cumulative survival rates of 96.4% and 94.1% for implant-based analysis and patient-based analysis, respectively. The mean ESBG, MBL, and BICL at the latest follow-up were 1.95±0.88 mm, 0.58±0.68 mm, and 5.51±1.47 mm. ESBG was found to be positively correlated to IPL. A significant decreased bone formation efficiency was found when IPL was over 4 mm (P=0.02). Conclusions An optimal range of IPL within 4 mm was recommended for better long-term outcomes when applying non-grafting OSFE with simultaneous implant placement.

Maxillary sinus floor augmentation comparing removing versus retaining antral pseudocyst: A retrospective cohort study

“…tween the LC group and the RC group. The correlation between implant protrusion length and bone formation and the correlation between residual bone conditions and marginal bone loss were both illustrated in previous studies(Galindo-Moreno et al, 2015;Klijn et al, 2012;Park et al, 2019;Yu et al, 2021). Therefore, we measured these parameters during the immediate postoperative period.…”

Cushioned grind‐out technique transcrestal sinus floor elevation for simultaneous implantation in severe atrophic maxilla: A retrospective study with up to 7 years of follow‐up

“…ESBG is a repeated measured variable (Table S4), the baseline was immediately after surgery (T1), and the follow‐up time point was pre‐prosthetic restoration (T2). Of the 23 confounding variables (Yu et al, 2021), five variables had poor standardized difference scores. After PSM, there were 51 patients with 61 implants in the RBH ≤ 4 mm group and 73 patients with 112 implants in the RBH > 4 mm group, which declined from a median of 5.97 to 5.05 mm, from a median 3.40 to 2.69 mm, respectively (Table 4).…”

Endo-sinus bone gain following osteotome-mediated sinus floor elevation with Bio-Oss Collagen compared with no grafting material: a one-year single-blind randomized controlled trial

“…19,[28][29][30] However, the increased implant protrusion length seems not to be proportional to the amount of ESBG. 12,13 A previous study revealed a decrease in ESBG when the implant protrusion length exceeded 4 mm. 12 Moreover, an increased implant protrusion length in conjunction with OMSFE without a grafting material creates a larger cavity underneath the elevated membrane, which causes a greater pressure on the membrane during the early healing period, with the risk of the coagulum dissolving and compromised bone regeneration.…”

“…12,13 A previous study revealed a decrease in ESBG when the implant protrusion length exceeded 4 mm. 12 Moreover, an increased implant protrusion length in conjunction with OMSFE without a grafting material creates a larger cavity underneath the elevated membrane, which causes a greater pressure on the membrane during the early healing period, with the risk of the coagulum dissolving and compromised bone regeneration. 13 Consequently, it is recommended that the exposed implant surface within the maxillary sinus does not exceed 5 mm following OMSFE with or without a grafting material.…”

“…11 Hence, opposing conclusions have been reported regarding the amount of ESBG following OMSFE with or without a grafting material, indicating that bone regeneration could be influenced by other aspects such as the grafting material used, implant protrusion length within the maxillary sinus, residual bone height, radiographic assessment method, or length of the observation period. 12,13 ESBG following OMSFE with or without a grafting material is frequently assessed using two-dimensional (2D) linear measurements on radiographs or cone beam computed tomography (CBCT) scans. 7,[14][15][16] However, the grafting material applied within the maxillary sinus is an inhomogeneous and three-dimensional (3D) anisotropic structure, which necessitates the use of 3D radiographic modalities for accurate assessment of ESBG and volumetric changes of the grafting material over time.…”