Effect of Schneiderian Membrane Thickening on the Maxillary Sinus Augmentation and Implantation Outcomes: A Systematic Review

Atypical and Late-Developed Sinus Graft Complications Following Maxillary Sinus Augmentation: Successful Management with Guided Bone Regeneration

Complications that occur after maxillary sinus floor augmentation (MSA) can be divided into early and late complications. Early complication is a side effect that occurs during the MSA procedure or during the initial healing period. Usually, late complication refers to a side effect that occurs after 3 weeks of MSA. However, in the longer term, there are cases that occur during the follow-up period after the prosthesis is delivered, and most of them present with peri-implantitis. In the present two cases, sinus graft complications occurred 1-2 years after prosthesis delivery but were independent of peri-implantitis and had atypical features showing asymptomatic results. Although the route of the infection source is unclear, the lesions were presumed to be caused by slow and delayed inflammation of oral bacteria infiltrating the bone graft area of the maxillary sinus. Within the limitations of present case reports, bone defects were successfully managed with a guided bone regeneration (GBR) procedure that included thorough defect degranulation, surface decontamination of exposed implant, and regrafting. Periodic monitoring of radiographic images is required for the detection of unusual sinus graft complications in sinus-augmented sites.

Maxillary sinus augmentation via the bone lid technique: A prospective, radiographic case series

BACKGROUND

Maxillary sinus augmentation is one of the most performed procedures to increase the bone quantity of the atrophic maxilla to allow implant placement. The aim of the present case series was to describe a surgical protocol to perform maxillary sinus augmentation with the "bone lid technique," and its outcomes in a cohort of patients eligible for the procedure.

METHODS

After the initial clinical evaluation, a cone-beam computed tomography (CBCT) examination was performed for preoperative assessment. Patients were then scheduled for surgical intervention. At 6-9 months follow-up, patients underwent a second CBCT scan to evaluate bone height following bone graft and to schedule implant placement.

RESULTS

A total of 11 patients were enrolled in the study with a total of 13 sinus lift procedures. Membrane perforation was registered in 4 cases (30.76%). Mean surgical time was 67.69 min (SD 6.51). Postoperative period was uneventful in all patients, in the absence of complications. The mean graft volume increase was 2.46 cm3 (SD 0.85), and the mean height increase was 14.27 mm (SD 3.18). Mean membrane thickness was 1.40 mm (SD 0.75). In all the 4 cases with sinus membrane perforation, the membrane had a thickness lower than 1 mm.

CONCLUSIONS

The present study highlights that the maxillary sinus augmentation with bone lid repositioning could provide repeatable results in terms of bone height increase. The technique appears reliable both in terms of bone gain and absence of complications.

KEY POINTS

The bone lid technique for maxillary sinus augmentation provides repeatable results in terms of bone height increase. The favorable clinical outcomes can be related to an enhancement of bone formation due to the unique osteoconductive and osteoinductive properties of autogenous bone, along with a reduction of soft tissue ingrowth. Complications were not observed in any of the patients following the surgical procedures. The risk of Schneiderian membrane perforation is inversely proportional to membrane thickness; the thinner the membrane is, the higher the risk to perforate it.

Comparison of 2D, 2.5D, and 3D segmentation networks for maxillary sinuses and lesions in CBCT images

BACKGROUND

The purpose of this study was to compare the segmentation performances of the 2D, 2.5D, and 3D networks for maxillary sinuses (MSs) and lesions inside the maxillary sinus (MSL) with variations in sizes, shapes, and locations in cone beam CT (CBCT) images under the same constraint of memory capacity.

METHODS

The 2D, 2.5D, and 3D networks were compared comprehensively for the segmentation of the MS and MSL in CBCT images under the same constraint of memory capacity. MSLs were obtained by subtracting the prediction of the air region of the maxillary sinus (MSA) from that of the MS.

RESULTS

The 2.5D network showed the highest segmentation performances for the MS and MSA compared to the 2D and 3D networks. The performances of the Jaccard coefficient, Dice similarity coefficient, precision, and recall by the 2.5D network of U-net +  + reached 0.947, 0.973, 0.974, and 0.971 for the MS, respectively, and 0.787, 0.875, 0.897, and 0.858 for the MSL, respectively.

CONCLUSIONS

The 2.5D segmentation network demonstrated superior segmentation performance for various MSLs with an ensemble learning approach of combining the predictions from three orthogonal planes.

Change in Maxillary Sinus Mucosal Thickness in Patients with Preoperative Maxillary Sinus Mucosal Thickening as Assessed by Otolaryngologists: A Retrospective Study

Background and Objectives: Maxillary sinus pathologic conditions may increase the risk of complications during posterior maxillary sinus augmentation surgery. The purpose of this study was to evaluate the changes in participants with preoperative maxillary sinus mucosal thickening and to assess this factor as a preoperative risk indicator for sinusitis after maxillary dental implantation. Materials and Methods: We compared the preoperative and postoperative maxillary sinus mucosal thickness (MSMT), the distance between the maxillary sinus ostium and sinus floor (MOD), and the MSMT/MOD ratio. The participants were divided into three groups (sinus augmentation, bone grafting, and no grafting). Results: The mean preoperative MSMT was 4.3 ± 2.0 mm, and the mean MSMT/MOD ratio was 0.13 ± 0.05. No postoperative sinusitis was observed in these patients, including cases caused by anatomical variations. The mean postoperative MSMT was 4.5 ± 2.3 mm, and the mean postoperative MSMT/MOD ratio was 0.15 ± 0.06. There was no statistically significant difference between the groups at each time point (p > 0.05). Conclusions: The study found no significant change in MSMT at post-treatment evaluation, even when considering different subgroups. It underscores the importance of preoperative maxillary sinus radiographic assessments and collaboration between dentists and otolaryngologists for better outcomes in patients with preoperative maxillary sinus mucosal thickening.

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

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.

Predictors of peri-implant bone remodeling outcomes after the osteotome sinus floor elevation: a retrospective study

BACKGROUND

This study aimed to evaluate the radiographic outcomes of implants after osteotome sinus floor elevation (OSFE), and further identify the separate predictors for these radiographic outcomes.

METHODS

In this retrospective cohort study, a total of 187 implants were inserted into 138 patients using the OSFE technique. Seventy-four patients in the grafted group, and 64 patients in the non-grafted group completed this study. The vertical bone gain (VBG) and marginal bone loss (MBL) at 3 years following surgery were assessed as outcome variables. Based on extensive literature results, variables considered potential predictors of outcome variables included sex, age, tooth position, implant length, implant diameter, with or without grafting materials, residual bone height, sinus width, bone density, and sinus membrane thickness. Subsequently, the binary logistic regression analysis was applied with VBG and MBL as dependent variables, respectively. The receiver operating characteristic curve (ROC) with its area under the curve (AUC) was performed to further determine the predictive value of these predictors.

RESULTS

One hundred and six implants in grafted group and 81 implants in the non-grafted group were analyzed. The average VBG was 2.12 ± 1.94 mm for the grafted group and 0.44 ± 1.01 mm for the non-grafted group at 3 years (P < 0.05). The mean MBL was 1.54 ± 1.42 mm for the grafted group and 1.13 ± 1.69 mm for the non-grafted group at 3 years (P > 0.05). After the adjustment for confounders, logistic regression analysis demonstrated that implant length, grafting, residual bone height, and sinus membrane thickness were predictors of VBG. The odds ratio for VBG was 3.90, 4.04, 4.13 and 2.62, respectively. Furthermore, grafting exhibited the largest AUC at 0.80. While tooth position and implant length were predictors of MBL, the odds ratio for MBL was 3.27 and 7.85, respectively. Meanwhile, implant length exhibited the largest AUC at 0.72.

CONCLUSIONS

OSFE with or without simultaneous grafting materials both showed predictable clinical outcomes. Additionally, the present study is the first quantitative and significant verification that VBG has a significant association with sinus membrane thickness, as well as residual bone height, implant length and grafting. Whereas tooth position and implant length are markedly associated with MBL.