Change in sinus membrane dimension following sinus floor elevation: a retrospective cohort study

Maxillary sinus floor augmentation: a review of current evidence on anatomical factors and a decision tree

Maxillary sinus floor augmentation using lateral window and crestal technique is considered as predictable methods to increase the residual bone height; however, this surgery is commonly complicated by Schneiderian membrane perforation, which is closely related to anatomical factors. This article aimed to assess anatomical factors on successful augmentation procedures. After review of the current evidence on sinus augmentation techniques, anatomical factors related to the stretching potential of Schneiderian membrane were assessed and a decision tree for the rational choice of surgical approaches was proposed. Schneiderian membrane perforation might occur when local tension exceeds its stretching potential, which is closely related to anatomical variations of the maxillary sinus. Choice of a surgical approach and clinical outcomes are influenced by the stretching potential of Schneiderian membrane. In addition to the residual bone height, clinicians should also consider the stretching potential affected by the membrane health condition, the contours of the maxillary sinus, and the presence of antral septa when evaluating the choice of surgical approaches and clinical outcomes.

Minimally invasive techniques for lateral maxillary sinus floor elevation: small lateral window and one-stage surgery-a 2-5-year retrospective study

This study aimed to introduce a minimally invasive technique for maxillary sinus floor elevation using the lateral approach (lSFE) and to determine the factors that influence the stability of the grafted area in the sinus cavity. Thirty patients (30 implants) treated with lSFE using minimally invasive techniques from 2015 to 2019 were included in the study. Five aspects of the implant (central, mesial, distal, buccal, and palatal bone heights [BHs]) were measured using cone-beam computed tomography (CBCT) before implant surgery, immediately after surgery (T0), 6 months after surgery (T1), and at the last follow-up visit (T2). Patients' characteristics were collected. A small bone window (height, (4.40 ± 0.74) mm; length, (6.26 ± 1.03) mm) was prepared. No implant failed during the follow-up period (3.67 ± 1.75) years. Three of the 30 implants exhibited perforations. Changes in BH of the five aspects of implants showed strong correlations with each other and BH decreased dramatically before second-stage surgery. Residual bone height (RBH) did not significantly influence BH changes, whereas smoking status and type of bone graft materials were the potentially influential factors. During the approximate three-year observation period, lSFE with a minimally invasive technique demonstrated high implant survival rate and limited bone reduction in grafted area. In conclusion, lSFE using minimally invasive techniques was a viable treatment option. Patients who were nonsmokers and whose sinus cavity was filled with deproteinized bovine bone mineral (DBBM) had significantly limited bone resorption in grafted area.

Effects of different grafting materials on volumetric changes in the Schneiderian membrane following lateral maxillary sinus floor elevation: a preliminary study

OBJECTIVES

To investigate the potential influence of different grafting materials on maxillary sinus membrane dimensions and ostium patency following lateral sinus floor elevation (SFE) as assessed using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

A total of 40 sinuses in 40 patients were included. Twenty sinuses were referred for SFE with deproteinized bovine bone mineral (DBBM), and the remaining 20 sinuses were grafted with calcium phosphate (CP). CBCT was performed prior to and 3 to 4 days after surgery. The dimensions of the Schneiderian membrane volume and ostium patency were evaluated, and potential relationships between volumetric changes and any associated factors were analyzed.

RESULTS

The median increase in membrane-whole cavity volume ratios was 43.97% in the DBBM group and 67.58% in the CP group, demonstrating no statistically significant difference (p = 0.17). The rates of increased obstruction after SFE were 11.1% for the DBBM group versus 44.4% for the CP group (p = 0.03). The graft volume was found to be positively correlated with the postoperative membrane-whole cavity volume ratio (r = 0.79; p < 0.01) and the membrane-whole cavity volume ratio increase (r = 0.71; p < 0.01).

CONCLUSIONS

The two grafting materials seem to have a similar effect on transient volumetric changes in the sinus mucosa. However, the choice of grafting material should still be made with caution since sinuses grafted using DBBM exhibited less swelling and less ostium obstruction.

Sinus augmentation procedure via the lateral window technique-Reducing invasiveness and preventing complications: A narrative review

Sinus augmentation has become an integrated surgical phase in posterior maxillary implant prosthesis reconstruction. Since the residual alveolar bony height usually requires additional volume particularly at this anatomical region, sinus floor augmentation is advocated routinely. Over the years, Implant success rate is proved to be comparable to the one in the pristine bone, which is well documented in the literature. Anatomical aspects as well as surgeon skills are at most importance to achieve predictable outcome. In this narrative review, the different osteotomy techniques, the indications toward 1 or 2-stage approaches, the control of the Schneiderian membrane integrity as well as the management of intra- and post-operative complications are thoroughly discussed according the current data. In light of the excellent long-term implant success rate concurrent with the application of contemporary advanced techniques of the sinus augmentation via the lateral wall osteotomy approach, reduce invasiveness and less complication occurrences are well documented. A well-codified patient selection involving the rhinologist as an integral medical team would be significantly beneficial toward early diagnosis. In-depth knowledge of the anatomy, execution of a well standardized surgical technique, and understanding the complication etiology and their management are prerequisites for reducing patient morbidity to minimal discomfort and predictable successful outcome.

Gingival Biotype and Its Relationship With the Maxillary Membrane and Lateral Wall Thickness

The purpose of this study was to analyze the risk of the maxillary sinus lift technique and the correlation between the thickness of the gingiva, maxillary sinus membrane, and the maxillary sinus lateral wall. Cone-beam computerized tomograhy (CBCT) records of 32 adult dentate patients (10 male/22 female) were analyzed. The gingival thickness records of the dental units were compared with the thickness measurements of the membrane and lateral wall of the maxillary sinus. The gingival biotypes varied between 1.1 mm (thin) and 1.6 mm (thick), with a small association with sex. The thickness of the sinus membrane presented a small association between sexes (0.2 mm, female/0.3 mm, male) and gingival biotypes (Cohen d = .52). The lateral wall presented a weak association between the biotypes (1.3 mm, thin/1.1 mm, thick). There was also no correlation between the membrane and lateral wall (r = -.22). The volume dimension related to the graft area of the sinus was 4 mm3 for men and 5 mm3 for women. There was a weak correlation of gingival thickness compared with membrane thickness and lateral wall of the sinus (r = .304/r = -.31). Gingival thickness does not appear to be a reliable thickness predictor of the membrane or lateral wall of the maxillary sinus. The analysis of maxillary sinus anatomical structures through CBCT is the most reliable technique to identify the thickness of the membrane and lateral wall of the maxillary sinus before surgery. We believe that new studies are necessary to confirm our findings.

The clinical and radiographic outcomes of Schneiderian membrane perforation without repair in sinus elevation surgery

BACKGROUND

The aim of this comparative study was to evaluate the clinical outcome of nonrepair of the perforated maxillary sinus membrane compared to the nonperforated cases.

MATERIALS AND METHODS

A retrospective comparative study was performed by identifying all lateral window sinus augmentation procedures, which were done during a defined period. Demographic data, systemic diseases, and smoking habits of patients were recorded. Thickness of the Schneiderian membrane and the amount of residual bone before surgery were measured by cone-beam computed tomography (CBCT). In case of perforation, no attempt was made to repair the membrane. Alloplast was used for bone augmentation. The thickness of the Schneiderian membrane and gained bone height were recorded using CBCT at the time of prosthesis delivery.

RESULTS

Sixty-three patients with 65 sinuses were included in this retrospective study. The rate of sinus perforation was 39%. There was a significant association between the presence of sinus pathoses before surgery and the occurrence of Schneiderian membrane perforation (P = 0.03). The Schneiderian membrane was significantly thicker in patients with perforation compared to the patients without perforation (P < 0.001). There was no correlation between the size of the perforation and the thickness of the Schneiderian membrane. Most of the perforations (83%) occurred at the mesial and middle part of the lateral window. The Schneiderian membrane thickness was decreased significantly in both groups after the sinus elevation procedure (P < 0.05). The bone graft height was stable over the follow-up period in both groups (P > 0.05). There was no implant failure in any of the groups.

CONCLUSIONS

Nonrepair of the Schneiderian membrane perforation did not adversely affect the clinical and radiographical outcomes. There were higher intraoperative and postoperative complications in the nonrepair group.

Analysis of maxillary sinus septa by cone-beam computed tomography

Abstract Introduction Pneumatization of the maxillary sinus may make it impossible to insert implants directly in the posterior region of the maxilla, and in these cases, the solution is to submit the patient to maxillary sinus floor augmentation surgery. The most common complication of this surgery is sinus membrane perforation. Anatomical variations of the internal space of the sinus, such as the bone septa, may further hamper detachment of this membrane. Objective To evaluate the prevalence and characteristics of sinus septa in patients from the Zona da Mata Mineira (Minas Gerais, Brazil), to offer relevant information for a safer planning of surgeries involving this region. Material and method A total of 120 patients (240 sinuses) were analyzed using cone-beam computed tomography (CBCT) images, verifying the presence of sinus septa and classifying them for size and anteroposterior location. Result Of the 120 patients analyzed, 45 (37.50%) had sinus septa, 66 septa in total. Of these, 33 (50%) were present in the middle region of the maxillary sinus and the mean septum size was 7.23 mm. There was no significant difference in the septum size between the genders or between the right and left sides. Conclusion The high rates of incidence of sinus septa justify their study, which should be based mainly on accurate exams, such as CBCT, since they represent one of the most relevant anatomical variations for the cases of sinus surgeries.

Crestal Sinus Augmentation in the Presence of Severe Sinus Mucosal Thickening: A Report of 3 Cases

PURPOSE

In the presence of severe sinus mucosal thickening, the ostium can be blocked when the sinus membrane is lifted, causing drainage disturbances and sinusitis. Here, we present 3 cases in which maxillary sinus floor elevation was performed using a crestal approach in the presence of severe sinus mucosal thickening (>10 mm).

MATERIALS AND METHODS

The effects of maxillary sinus floor elevation using the crestal approach technique on sinus mucosal thickening and bone formation in the sinus were evaluated using cone beam computed tomography.

RESULTS

None of the patients exhibited an increase in sinus membrane thickness. No complications were encountered during the follow-up periods, and bone formation was observed around the implants at the sinus floor. All implants were functioning successfully.

CONCLUSIONS

Maxillary sinus floor elevation using the crestal approach technique in the presence of severe sinus mucosal thickening allows for minimally invasive sinus grafting and simultaneous implant placement and does not increase sinus membrane thickness.

Potential risk factors for maxillary sinus membrane perforation and treatment outcome analysis

BACKGROUND

Most common complication of sinus floor elevation (SFE) is sinus membrane perforation (SMP).

PURPOSE

To investigate the correlation between SMP and potential risk factors and to evaluate SMP treatment outcomes.

MATERIALS AND METHODS

This study included patients who had undergone a SFE at Division of Oral Surgery and Orthodontics, Medical University of Graz from 2013 to 2017. Analysis of patients' records and CBCT focused on patient-related risk factors (sinus contours, thickness of membrane and lateral sinus wall, interfering septa, crossing vessels, former oroantral communication) and intervention-related risk factors (surgical approach, sides, number of tooth units, and sites). The outcome of SMP treatment was analyzed in the recalls.

RESULTS

In all, 121 patients underwent 137 SFE. There were 19 cases of SMP (13.9%). Two significant factors were identified: maxillary sinus contours (P = .001) and thickness of the sinus membrane (P = .005). The sinus membrane perforation rate was highest in narrow tapered sinus contours and when the sinus membrane was thinner than 1 mm. Among 19 cases with SMP, no complications were seen upon recall.

CONCLUSIONS

Maxillary sinus contours and sinus membrane thickness seem to be relevant factors for SMP. Sinus membrane perforations were successfully treated by coverage with collagen membrane.

Thickness of the Schneiderian membrane and its correlation with anatomical structures and demographic parameters using CBCT tomography: a retrospective study

Background

The aims of the present study were to determine the thickness of the Schneiderian membrane and identify the width of the maxillary sinus, which is indicated by the buccal and lingual walls of the sinus angle between. Furthermore, to investigate the possibility of a correlation between the aforementioned structures and also other anatomical and demographic parameters using CBCTs for dental implant surgical planning.

Methods

The study included CBCT images of 76 consecutive patients with field-of-view 15 × 12 or 12 × 8cm. Reformatted cross-sectional CBCT slices were analyzed with regard to the thickness of the Schneiderian membrane designated by the medial and the lateral walls of the sinus, in three different standardized points of reference. Age, gender, and position of the measurement were evaluated as factors that could influence the dimensions of the anatomical structures, using univariate and multivariate random effects regression model.

Results

The mean thickness of the Schneiderian membrane was 1.60 ± 1.20 mm. The average thickness revealed now differentiation by age (p = 0.878), whereas gender seemed to influence the mean thickness (p = 0.010). Also, the thickness of the Schneiderian membrane increased from medial to distal (p = 0.060). The mean value of the angle designated by buccal and lingual walls of the sinus was 73.41 ± 6.89 °. The angle measurements revealed no correlation with age, but a tendency towards lower mean angles in females (2.5 ° on average, p = 0.097). According to the anatomical position of the measurement, a differentiation was also detected. No correlation between thickness of the Schneiderian membrane and the angle of the walls of the sinus was concluded (p = 0.662).

Conclusions

This study demonstrated that the thickness of the Schneiderian membrane and the width of the maxillary sinus can only be affected by gender and anatomical position, but not by the age of the patient.

Volumetric changes of grafted volumes and the Schneiderian membrane after transcrestal and lateral sinus floor elevation procedures: A clinical, pilot study

AIM

To investigate the influence of various surgical techniques for sinus augmentation on the volumetric changes of graft, membrane and the post-operative discomfort.

MATERIALS AND METHODS

Eighteen patients in need of bilateral sinus floor elevation (SFE) were assigned to lateral SFE, transcrestal SFE and intralift procedures. CBCT images taken at baseline, 1 week and 6 weeks were analysed for volumetric changes in graft and Schneiderian membrane. Questionnaires were used to analyse post-op discomfort.

RESULTS

The overall average graft volume obtained after 1 week was 1.87 cm³ (range 0.12-4.72 cm³ ). Volumes decreased after 6 weeks to an overall mean volume of 1.33 cm³ (range 0.10-4.29 cm³ - average decrease of 27.6%). After 6 weeks, the amount of graft volume decreased in every treatment option, ranging from -23.13% for the tSFE, over -24.55% for the lSFE, to -33.71% for the IL. Although all treatment options correspond in an increase in Schneiderian membrane volume, no statistically significant correlation between this increase and loss of graft volume could be obtained for all treatments (p = 0.97).

CONCLUSION

All SFE techniques provided sufficient graft volume for implant treatment. All techniques provoke a partially transient swelling of the Schneiderian membrane. All techniques resulted in a decrease in graft volume after 6 weeks; however, no significant differences were obtained between treatments. Furthermore, no statistical significant correlation between the post-operative swelling of the Schneiderian membrane and reduction in graft volume at 6 weeks could be obtained.

Schneiderian Membrane Thickness and Clinical Implications for Sinus Augmentation: A Systematic Review and Meta-Regression Analyses

BACKGROUND

Schneiderian membrane thickness (SMT) has been regarded as a key factor for influencing membrane perforation, which may jeopardize the final clinical outcome of sinus augmentation. Hence, this systematic review aims at studying the mean SMT and further investigating patient-related factors that may affect SMT. As a secondary goal, the association between SMT and membrane perforation rate was studied.

METHODS

Three independent reviewers in several databases, including MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Oral Health Group Trials Register databases, conducted electronic and manual literature searches. This review was written and conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and MECIR (Methodological Expectations of Cochrane Intervention Reviews) guidelines. Quantitative assessment was performed for articles that met the inclusion criteria to investigate the mean SMT, its contributing factors, and the influence on membrane damage and surgical complications.

RESULTS

Thirty-one studies that reported maxillary SMT were considered for qualitative analysis. Nineteen were further meta-analyzed. Overall mean ± SE SMT was 1.17 ± 0.1 mm (95% confidence interval [CI] = 0.89 to 1.44). Although mean SMT for the three-dimensional radiography (3DR) group was 1.33 mm (95% CI = 1.06 to 1.60), for the histology group, it was 0.48 mm (95% CI = 0.12 to 1.1). Random-effects model showed that, although there is a trend for thicker SMT as determined using 3DR compared with histologic analysis, such difference did not reach statistical significance (P = 0.15). Also, regression analyses demonstrated that the variables periodontitis (P = 0.13) and smoking (P = 0.11) showed thicker SMT. Inconclusive data were obtained when correlating SMT and perforation rate, although it seems that thicker SMT might be more prone to perforation (P = 0.14).

CONCLUSIONS

SMT is, on average, 1 mm in patients seeking sinus augmentation. Three-dimensional technologies overestimate approximately 2.5 times SMT when compared with histologic analysis. Periodontitis and smoking may result in thickening of the sinus membrane. However, current data were inconclusive to link SMT to the rate of membrane damage.

Accuracy of Schneiderian membrane thickness: a cone-beam computed tomography analysis with histological validation

OBJECTIVES

Cone-beam computed tomography (CBCT) has been used in the literature to evaluate Schneiderian membrane thickness (SMT), but its accuracy has never been validated. The primary aim of this study was to compare the SMT measured by CBCT to the gold standard histological assessment. The correlations between SMT and anatomical structures of the maxillary sinus and alveolar bone were also tested.

MATERIALS AND METHODS

Fourteen fresh cadaver heads were used for the study, and 28 sinus lift augmentation procedures were performed to obtain the membrane samples. Samples were fixed in formalin and stained with hematoxylin-eosine and Masson trichrome. Specimens were measured by optic microscope at three points, and a mean was obtained. Anatomical landmarks were used to accurately position the CBCT slice, so the SMT could be measured in predetermined locations. Wilcoxon signed-rank test was used to compare values of histological and CBCT measurements, and Spearman's correlation coefficient was calculated to examine the relationship between thickness and anatomical parameters.

RESULTS

A total of 597 histological measurements were performed, and the mean SMT thickness was 0.30 ± 0.17 mm. The mean CBCT membrane thickness was 0.79 ± 0.52 mm. A statistically significant difference from histological and radiological readings was observed (P = 0.000). Interestingly, 87.77% histological measurements had membrane less than 0.5 mm in thickness compared to 26.66% in CBCT assessment.

CONCLUSIONS

Within the limitation of this study, the median histological Schneiderian membrane thickness was 0.30 mm. Cone-beam computed tomography assessment was 2.6 times higher than the histological examination.

Longitudinal response of membrane thickness and ostium patency following sinus floor elevation: a prospective cohort study

OBJECTIVES

To investigate the influence of sinus floor elevation (SFE) on sinus physiology, including Schneiderian membrane thickness (MT) and ostium patency, using cone beam computed tomography (CBCT).

MATERIALS AND METHODS

Based on pre-established selection criteria, 53 patients in combination with 53 sinuses were referred for SFE with a lateral approach using deproteinized bone mineral. CBCT was performed prior to, immediately after surgery and before staged implant placement. The Schneiderian MT of the elevated region, ostium patency, and other clinical data was evaluated.

RESULTS

The two-stage sinus augmentation technique was applied in 33 males and 20 females. Four membrane perforations were observed during the surgical procedure. The Schneiderian membrane exhibited significant swelling immediately after augmentation (P < 0.0001), but this difference disappeared after a mean healing period of 7.51 months. The corresponding changes were also observed for ostium patency with a tendency of transient obstruction after surgery. Sinuses with flat mucosal thickening or pseudocysts did not present a liability of perforation compared to the normal cases, and the augmentation procedure was not likely to deteriorate the pathology of mucosal thickening or pseudocysts.

CONCLUSIONS

The results show that SFE with a lateral approach has no significant influence on MT and ostium patency after the healing period except for postoperative transient swelling and obstruction. Thickened membranes and antral pseudocysts in a small size might not be contraindications to SFE from the standpoint of the surgical impact on the Schneiderian membrane.

The influence of sinus membrane thickness upon membrane perforation during lateral window sinus augmentation

OBJECTIVES

To investigate: (1) sinus membrane thickness in patients receiving lateral window sinus augmentation via cone-beam computed tomography (CBCT) and (2) the influence of Schneiderian membrane thickness upon membrane perforation during lateral window approach.

MATERIAL AND METHODS

A total of 73 subjects with 81 sinus lift procedures between years 2010 and 2013 were recruited consequently. Each patient selected had CBCT images in initial and immediately after surgery. The values and correlation between variables of membrane thickness, perforation rate, membrane morphology, residual bone height, and elevated bone height were evaluated.

RESULTS

The mean thickness of the Schneiderian membrane was 1.32 ± 0.87 mm. Perforation rate was lowest (7.14%) when membrane thickness was 1-1.5 mm. As membrane became thicker (≥2 mm) or thinner (<1 mm), the perforation rate increased abruptly. When examined the membrane thickness category, Class B (between ≥1 mm and <2 mm) had the lowest perforation rate. Statistically significant correlation was found between the perforation and the membrane thickness. The amount of the remaining bone height did not significantly correlate to the membrane thickness nor influence the membrane perforation.

CONCLUSIONS

This study demonstrated that membrane thickness was related to the sinus perforation during lateral window sinus augmentation. The perforation rate was lowest when the membrane thickness was 1-1.5 mm.

Evaluation of anatomical considerations in the posterior maxillae for sinus augmentation

The edentulous posterior maxilla is considered a clinical challenge during dental implant treatment for many dental practitioners. This is because its insufficient bone quality, deficient alveolar ridge, spiny ridges, undercuts, and sinus pneumatization are often encountered after tooth loss. To overcome these problems, several approaches have been developed and are currently used, including sinus augmentation and bone augmentation. Today, two main procedures of sinus floor elevation for dental implant placement are in use: a two-stage technique using the lateral window approach, and a one-stage technique using a lateral or a crestal approach. In this study, we deal with the anatomic relations of the structures of the maxillary sinus during sinus augmentation. These anatomical findings can help in complications and potential injuries of the maxillary sinus procedures. It can be suggested that pre-operative evaluation is helpful for diagnosis and treatment planning and minimizing complication during the surgery.

The influence of sinus membrane thickness upon membrane perforation during transcrestal sinus lift procedure

OBJECTIVES

Schneiderian membrane perforation is one of the main complications during sinus augmentation. The reasons may be associated with surgical technique, septum, inadequate ridge height, and membrane thickness. However, reports that used cone-beam computed tomography (CBCT) to quantify the thickness of sinus membrane were limited. The aims of this retrospective study were: to study the correlation between membrane thickness and perforation rate during transcrestal sinus lift and to propose a classification system of sinus membrane thickness based upon CBCT data.

MATERIAL AND METHODS

One hundred and twenty-two subjects who received dental implant restorations over posterior maxilla with a total of 185 transcrestal sinus lift procedures between years 2010 to 2013 were selected consequently. Each patient selected had to have taken CBCT in the initial examination and immediately after surgery. The membrane thickness, perforation rate, residual bone height, and elevated bone height were recorded and processed for statistical analysis.

RESULTS

The mean thickness of the Schneiderian membrane was 1.78 ± 1.99 mm. There was a significant correlation between membrane thickness and perforation rate (P < 0.05), and the perforation rate was higher in thicker (≥3 mm) and thinner membrane (≤0.5 mm). Among the thickness group, Class B (between ≥1 and <2 mm) had the lowest perforation rate. No significant difference was between the perforation and the membrane morphology. A negative relationship between residual bone height and membrane thickness was found. Trend showed that in the thicker and the thinner residual bone height, the higher the perforation rate would be.

CONCLUSIONS

There was a significant correlation between membrane thickness and perforation rate. The perforation rate was lowest when the thickness was 1.5-2 mm.