Pre-operative measurement of the volume of bone graft in sinus lifts using CompuDent

Prediction of the bone volume for sinus augmentation through 3-dimensional analysis

Background/purpose

No consensus has been established regarding the exact amount of bone grafting in maxillary sinus augmentation. The aim of this study was to estimate the minimum bone volume for sinus augmentation and to investigate the factors that influence the augmentation volume (AV).

Materials and methods

This study included patients with cone-beam computed tomography scanning. Dome-shaped sinus augmentation was performed virtually at vertical heights (VH) of 3, 5, 7, and 9 mm in Group A (without implantation) and Group B (with implantation). The augmentation angle (AA) and the sinus width (SW) were measured. The AV was measured using the three-dimensional image processing program 3D Slicer. Univariable and multivariable analyses were conducted.

Results

This study included 30 patients (120 subjects). In Group A, the mean AVs were 0.062, 0.271, 0.642, and 1.287 cc at VHs of 3, 5, 7, and 9 mm, respectively, in Group B, the mean AVs were 0.037, 0.230, 0.594, and 1.230 cc. Univariable analysis indicated that factors significantly associated with the AV in both groups included SW, AA, and VH (P < 0.001). Multivariable analysis indicated that factors significantly associated with the AV in both groups included AA and VH (P < 0.01).

Conclusion

Clinicians can predict the bone volume for sinus augmentation by measuring the augmentation height and angle.

Treatment alternatives for the rehabilitation of the posterior edentulous maxilla

Rehabilitation of the edentulous maxilla with implant-supported fixed dental prostheses can represent a significant clinical challenge due to limited bone availability and surgical access, among other factors. This review addresses several treatment options to replace missing teeth in posterior maxillary segments, namely the placement of standard implants in conjunction with maxillary sinus floor augmentation, short implants, tilted implants, and distal cantilever extensions. Pertinent technical information and a concise summary of relevant evidence on the reported outcomes of these different therapeutic approaches are presented, along with a set of clinical guidelines to facilitate decision-making processes and optimize the outcomes of therapy.

CBCT for Diagnostics, Treatment Planning and Monitoring of Sinus Floor Elevation Procedures

Sinus floor elevation (SFE) is a standard surgical technique used to compensate for alveolar bone resorption in the posterior maxilla. Such a surgical procedure requires radiographic imaging pre- and postoperatively for diagnosis, treatment planning, and outcome assessment. Cone beam computed tomography (CBCT) has become a well-established imaging modality in the dentomaxillofacial region. The following narrative review is aimed to provide clinicians with an overview of the role of three-dimensional (3D) CBCT imaging for diagnostics, treatment planning, and postoperative monitoring of SFE procedures. CBCT imaging prior to SFE provides surgeons with a more detailed view of the surgical site, allows for the detection of potential pathologies three-dimensionally, and helps to virtually plan the procedure more precisely while reducing patient morbidity. In addition, it serves as a useful follow-up tool for assessing sinus and bone graft changes. Meanwhile, using CBCT imaging has to be standardized and justified based on the recognized diagnostic imaging guidelines, taking into account both the technical and clinical considerations. Future studies are recommended to incorporate artificial intelligence-based solutions for automating and standardizing the diagnostic and decision-making process in the context of SFE procedures to further improve the standards of patient care.

Evaluation of the effect of direct sinus lift surgery on maxillary sinus volume by Mimics software

Introduction

Sinus lift surgery allows sufficient volume of bone to be created in the posterior part of the maxilla. The aim of this study was to investigate the changes in maxillary sinus volume after a sinus lift and the rate of increase in ridge height at the site of the graft.

Methods

Eleven patients were chosen for sinus lift from among those who were referred to the radiology department for implant placement in the posterior region of the maxilla and whose bone height at the posterior of the maxilla was less than 4 mm on the cone-beam computed tomography (CBCT) image. The sinus volume was measured after importing the CBCT file in DICOM format into Mimics software. After determining the sinus volume, the patients underwent sinus lift surgery, and the amount of material used during the surgery was measured. After the time required to repair the area, the CBCT image was taken again. Then, the changes in the volume of the maxillary sinus and the increase in the height of the maxillary ridge at the surgical site were calculated. Then, the second stage of the surgery was performed to place the implant at the implant site.

Results

For an average of 1.40 cm3 of material, the rate of increase in ridge height was 10.52 mm, and the average change in sinus volume was 1.19 cm3.

Conclusions

CBCT images and Mimics software have many applications in examining and predicting parameters before and after sinus lift surgery.

Patient-specific estimation of the bone graft volume needed for maxillary sinus floor elevation: a radiographic study using cone-beam computed tomography

OBJECTIVE

To develop prediction models for estimating the bone-graft volume needed for sinus floor elevation (SFE) based on the augmentation site, elevation height, and sinus width using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

CBCT scans with a medium-to-large field-of-view with bilateral maxillary sinuses partially/entirely visible, acquired from February 2016 to October 2020, were initially screened. Ten defined regions, above the maxillary first (MM₁) and second molar (MM₂) sites, in the sinuses of the included CBCTs were semi-automatically segmented, and the volumes of the regions were automatically measured using the ITK-SNAP program. The sinus widths at the height ranging between 8 and 16 mm from the sinus floor were measured at the MM₁ to MM₂ sites, respectively. Multiple linear regression analyses were performed to establish prediction models for estimating the bone graft volume needed for SFE at the MM₁ and/or MM₂ sites with the sinus width and elevation height as predictors.

RESULTS

A total of 133 scans (224 sinuses) were included. Three developed prediction models, composed of the sinus width and elevation height, explained 89-91% of the variation in the bone graft volumes estimated for SFE at the MM₁, MM₂, and MM₁-MM₂ sites. The mean absolute deviations and absolute percentage deviations between the measured and predicted volumes ranged from 0.12 to 0.28cm³ and from 9.78 to 10.62%, respectively.

CONCLUSION

The proposed prediction models may enable more patient-specific estimation of the bone graft volume needed for SFE.

CLINICAL RELEVANCE

The proposed prediction models could facilitate the preparation of an adequate amount of bone graft material and patient-clinician communication about the cost of bone graft material.

Surgeons' Performance Determining the Amount of Graft Material for Sinus Floor Augmentation Using Tomography

This study aimed to assess the performance of surgeons in determining the amount of graft material required for maxillary sinus floor augmentation in a preoperative analysis using cone-beam computed tomography images. A convenience sample of 10 retrospective CBCT exams (i-CAT®) was selected. Scans of the posterior maxilla area with an absence of at least one tooth and residual alveolar bone with an up to 5 mm height were used. Templates (n=20) contained images of representative cross-sections in multiplanar view. Ten expert surgeons voluntarily participated as appraisers of the templates for grafting surgical planning of a 10 mm long implant. Appraisers could choose a better amount of graft material using scores: 0) when considered grafting unnecessary, 1) for 0.25 g in graft material, 2) for 0.50 g, 3) for 1.00 g and 4) for 1.50 g or more. Reliability of the response pattern was analyzed using Cronbach's a. Wilcoxon and Mann-Whitney tests were performed to compare scores. Regression analysis was performed to evaluate whether the volume of sinuses (mm3) influenced the choose of scores. In the reliability analysis, all values were low and the score distribution was independent of the volume of the maxillary sinuses (p>0.05), which did not influence choosing the amount of graft material. Surgeons were unreliable to determine the best amount of graft material for the maxillary sinus floor augmentation using only CBCT images. Surgeons require auxiliary diagnostic tools to measure the volume associated to CBCT exams in order to perform better.

Update of Surgical Techniques for Maxillary Sinus Augmentation: A Systematic Literature Review

OBJECTIVE

A wide range of surgical techniques are available for maxillary sinus augmentation. This review aimed to determine which techniques have achieved the highest success rates and so offer the greatest predictability.

MATERIALS AND METHODS

A systematic literature review was performed using the PubMed, MEDLINE, and Scopus databases, identifying clinical trials that assessed different surgical techniques for maxillary sinus augmentation, and registered the success rates of subsequent implant placement.

RESULTS

A total of 40 articles described clinical studies involving different maxillary sinus augmentation procedures with follow-up periods of at least 6 months after dental implant placement. Implant success rates varied between 94% and 100% during the follow-up periods.

CONCLUSION

A wide variety of clinical techniques are available for maxillary sinus augmentation; the choice of the technique will depend chiefly on the characteristics of the edentulous site, which will permit or prevent the placement of the implant at the moment of sinus augmentation surgery.

Bacterial influence on consolidation of bone grafts in maxillary sinus elevation

OBJECTIVES

The aim of this study was to identify microorganisms present on the maxillary sinus floor at the moment of sinus elevation surgery and, using tomography, to investigate the repercussions these might have for regenerated bone 9 months after the procedure.

MATERIALS AND METHODS

174 patients (90 women and 84 men) with a mean age of 55.92 years underwent 227 sinus elevations (120 left sinus, 107 right sinus). As the membrane was lifted, a sample of the maxillary sinus floor was collected with a cotton swab, and placed on a blood agar and chocolate agar culture to incubate for 48 h at 37°C; the samples then underwent microbiological analysis. Orthopantomographs and computerized tomographs were made immediately after the sinus grafting and after 9 months to measure the amount of remaining and regenerated bone in vertical and transversal direction.

RESULTS

18.1% of 227 cultures were bacteria-positive. 45% of the germs were of the Streptococcus genus, most of which belonged to the S. viridans group (61.1%). Patients presenting negative cultures had 5% more regenerated bone than patients with bacteria-positive cultures, which represents an additional 2.28 mmof vertical bone (with a confidence interval between 0.83 mm and 3.73 mm).

CONCLUSIONS

Patients with bacteria-positive cultures obtained previously to the sinus grafting procedure have greater risk of bone height loss after 9 months, which indicates that bacterial contamination may influence bone graft regeneration.

Evaluation of Three-Dimensional Volumetric Changes After Sinus Floor Augmentation with Mineralized Cortical Bone Allograft

AIM

The aim of this retrospective study was to quantify three-dimensional (3D) volumetric bone changes over a two-year period in maxillary sinuses augmented with a mineralized cortical bone allograft material (MCBA) material.

PATIENTS AND METHODS

Eleven patients (6 males and 5 females) with mean of age of 51.6 (range: 46-61) years were treated to increase the vertical dimension of the alveolar crest by maxillary sinus floor augmentation procedure. Study data were collected from patient records and by analyzing preoperative radiographs and cone beam computed tomography (CBCT) scans taken within the first two weeks after maxillary sinus lift (T0), immediately before implant placement four months after grafting (T1), and after one year of implant loading (T2). All DICOM-formatted images were rendered into volumetric images using software that automatically calculated the volume of the grafted material in cubic centimeters.

RESULTS

Mean graft volume was 16.24 ± 1.54 cm(3) at T0, 14.48 ± 1.48 cm(3) at T1 and 13.06 ± 1.39 cm(3) at T2. Mean volume retraction resulted in 1.76 ± 0.34 cm(3) ΔV1 (T0-T1) and 1.42 ± 0.4 cm(3) ΔV2 (T1-T2) and was 10.83 % of the initial total volume at (T0-T1) and 9.8 % of the total volume (T1-T2).

CONCLUSION

The present retrospective investigation demonstrated a 20.63 % decrease in graft volume. Volumetric 3D assessment of CBCT scans with the selected software appeared to be a promising approach to quantifying long-term changes in the grafted area.

A new method to evaluate volumetric changes in sinus augmentation procedure

BACKGROUND

In sinus augmentation procedure, the assessment of volume changes of grafted materials is important both in the clinical practice and in dental research to evaluate the features of filling materials.

PURPOSE

In this study, we assessed the repeatability of a new method proposed to evaluate volumetric changes following sinus lift augmentation procedure.

MATERIALS AND METHODS

In 10 patients, maxillary sinus augmentation procedure with simultaneous implant placement was performed. Maxillary cone beam computer tomographies were taken 1 week after surgery (T1) and 6 months after surgery (T2). At each evaluation the gap inside the implant between the fixture and the bottom of the screw was used as reference point (Rp), and a standardized volume of interest (VOI) centered on the Rp was selected. Masks were chosen to select the graft and bone tissue within the VOI; the volume at T1, T2, and the difference of volume between T1 and T2 were computed. Expert and non-expert operators performed the analysis. Method errors were computed.

RESULTS

The error of the method was 1% for both intra-operator and inter-operator measurements. Tissue contraction at T2 was 19 ± 4% of the total initial volume.

CONCLUSIONS

The standardization of the method allows to obtain repeatable measurements.