BACKGROUND: Different protocols and procedures for sinus lift and implant placement are available, generally involving the use of grafts to increase the tissue volume and/or prevent the Schneiderian membrane from collapsing. Among xenografts, deproteinised bovine bone graft (DBBP) is frequently used in sinus lift procedures. Leaving an ungrafted space following membrane elevation has proven to have a bony regenerative potential as well. This study aimed to compare the clinical and histological features of sinus lift surgery performed with or without biomaterials.
METHODS: Patients with severe maxillary posterior atrophy (residual bone height 2-6 mm and residual crest thickness ≥4 mm), and in need of sinus lift surgery to allow the placement of three implants were enrolled and randomly divided into two groups. They underwent sinus lifts with DBBP (control) or with a graftless technique (test) and immediate placement of two implants (a mesial and distal one). After 6 months, a bone sample was retrieved from the area between the previously inserted fixtures, and a third, central implant was placed. The collected bone samples were analyzed morphologically and histomorphometrically. The patients were provided with prosthetic restorations after 6 months and followed up for 5-12 years.
RESULTS: Ten patients were enrolled in the test and nine in the control group. The 6-month follow-up showed in the control group an average augmentation of 10.31 mm (±2.12), while in the test group it was 8.5 mm (±1.41) and a success rate of 96.3% in the control and 86.7% in the test group (p > 0.05). The histological analysis evidenced the presence of new bone tissue surrounded by immature osteoid matrix in the test group, and a variable number of DBBP particles surrounded by an immature woven bone matrix in the control group.
CONCLUSIONS: The results of the present trial indicate that, with residual bone height of 2-6 mm and residual crest thickness ≥4 mm, sinus lift surgery with or without biomaterials followed by implant restoration, produces similar clinical and histological outcomes.

Objectives: A mucous retention cyst is a common, asymptomatic lesion that may cause complications during or after the sinus lift procedure. The goal of this study is to assess the effectiveness of the Croco Eye Technique (CET), which allows simultaneous excision of the cyst and sinus floor elevation. Methods: The technique was thoroughly described in two versions, and the group of 33 patients was analyzed. Patients who qualified for this procedure had insufficient alveolar ridge height, and their CBCT showed radiological images typical for retention cysts. Analyzed parameters included the version of CET, demographic data, anatomical parameters, intraoperative complications, recurrence of the cyst, success rate of the sinus lift and implants, and the follow-up period. Results: Out of the 33 cases, 9 were of the primary version (27.27%) and 24 of the final version (72.73%). The average height of a retention cyst was 24.05 mm, with the average alveolar ridge height of 1.86 mm. In three cases (9.09%), implants were placed immediately. The prevalence of uncontrolled Schneiderian membrane perforation was reduced from 55.56% to 4.17% between the primary and final versions. The cyst\'s recurrence rate was 3.13%. The implant survival rate was 100%. The mean follow-up period was 48.625 months (max 110 months). Conclusions: The Croco Eye Technique, despite the perforation of the Schneiderian membrane, enables successful sinus lift and implantation with a success rate of 100%. Excision of the retention cyst, which is the cause of perforation, allows for limiting the risk of the cyst\'s recurrence.

OBJECTIVE: To analyze the visibility of the maxillary sinus septa (MSS) in panoramic radiography (PR) versus cone beam computed tomography (CBCT) and to investigate whether the buccal cortical bone thickness (BT) or the septa dimensions influence their visibility.
METHODS: Corresponding PR and CBCT images of 355 patients were selected and examined for MSS visibility. The septa dimensions (width, height, depth) and the BT were measured. Results were analysed statistically.
RESULTS: Comparing the corresponding regions on CBCT and PR, 170 MSS were identified; however, only 106 of these were also visible using PR. The MSS visibility was significantly higher on CBCT versus PR images (P1: p = 0.039, P2: p = 0.015, M1: p = 0.041, M2: p = 0.017, M3: p = 0.000), except region C (p = 0.625). Regarding the measurements of MSS dimensions, only the height in region M1 (p = 0.013) and the width in region P2 (p = 0.034) were significantly more visible on CBCT. The BT in the area of the MSS was found to have a marginal influence on its visibility on the PR images only in regions M3 and M1 (M3: p = 0.043, M1: p = 0.047). In terms of MSS visibility based on the dimensions, significance was found for all three influencing variables only in region P2 (width; p = 0.041, height; p = 0.001, depth; p = 0.007). There were only isolated cases of further significance: M3 for width (p = 0.043), M2 for height (p = 0.024), and P1 for depth (p = 0.034), no further significance was noted.
CONCLUSIONS: MSS visibility appears significantly higher on CBCT versus PR images. It is concluded that the septa dimensions and BT can influence MSS visibility on PR images just in certain regions.

OBJECTIVE: This study aims to investigate and determine the prevalence, location, and morphological differences of the maxillary sinus septa using cone beam computed tomography (CBCT) images in the Madina region and to discuss its clinical implications during sinus surgery.
METHODS: This study was a retrospective cross-sectional radiographic analysis of 808 CBCT scans from patients who attended Taibah University\'s College of Dentistry between December 2018 and June 2023. Age, gender, number of septa present per side, location (anterior, middle, posterior), morphology (complete or partial), and type (primary or secondary) were among the study variables. For data statistics, correlation analysis was utilized.  Results: Eight hundred eight CBCT scans were included with a mean age of 34.7±15.08. Septal bone was absent in 60.64% of the sinuses examined. Single septa were more common than multiple septa (p=0.009). Bilateral septal presence and the left septal bone were more common than the right, but none of these distributions were statistically significant. Males showed more sinus septa compared to females, but the difference was not statistically significant (p=0.420). Single septa were more prevalent in people under the age of 25.
CONCLUSIONS: More than 60% of the Madina population had patent sinus cavities with no septal processes, but males with single septal processes predominated.

Introduction. The presence of bone septum in the maxillary sinus is one of the most common anatomical findings. So-called Underwood septa (US) are an atypical bone formation in the maxillary sinuses. Mostly they are quite easily found in CBCT studies and have major importance in sinus lift procedures in dental surgery. Furthermore, the shape, location, and size of the bony septa are important in each maxillary sinus surgery. Material and methods. A retrospective study of 120CBCT scans from the authors\' own database was conducted. Results. Approximately 37.5% of each CBCT was associated with the occurrence of US, while just 25% had a full septum, and a total of only 14 patients had a half septa. More females have US, while healthy pneumatized maxillary sinus is most commonly found (82.22%). There is no correlation between the occurrence of silent sinus syndrome (p = 0.174), mucosal thickening (p = 0.325), or retention cyst formation (p = 0.272). Most sinuses are without any opacification in CBCT evaluation (91.11%), while other syndromes are not statistically relevant. Conclusions. It seems that the occurrence of Underwood septa is not statistically related to any clinical, radiological, or pathological condition within the sinus (p > 0.05). Furthermore, a more full or partial appearance of US was found in female patients.

Maxillary sinus grafting is considered the most common surgical technique to secure a sufficient bone height for placing dental implants. It is carried out either by making a bony window in the lateral wall of the maxillary sinus (the external procedure) or through the alveolar entrance technique by using alveolar osteotomes (the internal procedure), depending on the quality and quantity of the remaining bone.
The aim of the present study was to compare radiologically the amount of bone gain (an increase in bone dimensions) and bone reduction (the loss of the graft volume) obtained by using tricalcium phosphate (TCP) and calcium sulfate (CS) grafts mixed with advanced platelet-rich fibrin (A-PRF).
Nine patients (18 maxillary sinuses) participated in this study, all of whom had bilateral edentulism involving the premolar/molar areas and a bone height of 0.5-5 mm between the sinus floor and the alveolar ridge. Two biomaterials were used in the sinus augmentation procedures. Each patient underwent a bilateral maxillary sinus lift with the use of different bone graft materials - with CS mixed with A-PRF used on one side, and TCP mixed with A-PRF on the other side. The grafting site was selected randomly. Afterward, bone gain and bone reduction were evaluated at the grafting site by using cone-beam computed tomography (CBCT).
The mean bone gain on the side treated with TCP mixed with A-PRF was 7.532 ±1.150 mm, and on the side treated with CS mixed with A-PRF side it was 7.961 ±2.781 mm. The comparison of bone gain and bone reduction between the 2 groups showed no statistically significant differences at a 6-month follow-up.
Using CS or TCP mixed with A-PRF was beneficial and safe in the two-stage maxillary sinus lifting procedure. A sufficient amount of bone was obtained for dental implantation.

The objective of the present study was to evaluate the bone quality of sinus and alveolar grafts following filling with particulate allogenous bone (DFDBA 300-500μm) and platelet concentrate (platelet-rich fibrin, PRF). A prospective interventional clinical study was carried out. A total of 40 bone cores, 2mm in diameter, were taken from 21 patients: 22 from grafted alveoli, 7 from grafted sinus sites, and 11 from native bone used as a control. Fixed, paraffin-embedded samples were subjected to histological staining with hematoxylin-eosin and Masson\'s trichrome. Bone maturity of the samples was evaluated by two independent operators using histomorphometric analysis. There existed a greater proportion of lamellar neoformed bone than woven neoformed bone as the healing time increased. Moreover, there was also an increasing proportion of newly formed bone in the grafted sockets as a function of healing time (average: 41.22% ≤ 5 months, 55.89% ˃ 5 months). Resorption of DFDBA particles also appears to be correlated with healing time in the grafted socket (average: 15.43 ≤ 5 months, 13.72% ˃ 5 months). In conclusion, performing sinus lift and alveolar socket preservation techniques using DFDBA and PRF results in high quality, mature bone tissue according to histological criteria.

The aim of the study was to compare various methods used for the bone reconstruction in the anterior wall of the maxillary sinus during sinus lift surgery; in addition, we aimed to study the effect of maxillary sinus membrane perforation on the healing process.
The experiments were carried out using the North Caucasian sheep. Maxillary sinus lift surgery was performed on the animals under general anesthesia. The skin and muscle fascia were dissected layer-by-layer providing the optimal conditions for bone preparation; then, three bone windows were made on each side of the head. Two windows were sawn out with a spherical bur, the third window - with a hollow bur and part of the anterior wall was taken out. On one side, the mucous membrane of the maxillary sinus was pulled and perforated; on the other side, the sinus lift was performed with no membrane perforation. On each side, one window was left uncovered, the second was closed with a collagen membrane, and the third was closed with a bone cover. After 30 and 60 days, the sheep were taken out of the experiment in groups of three; samples were collected from the operated areas and examined using computed microtomography and histology.
According to the histological study, the bone repair process developed normally regardless of the surgery technique. The process started with the appearance of granulation tissue and connective tissue cords; in the final stages, cellular differentiation, pronounced osteoblastic activity, and inter-beam formation were seen.The most active regeneration was observed in the areas where the bone defects were closed with a collagen membrane, and especially in the windows made with no perforation of the maxillary sinus membrane. The microtomographic and histological tests proved that perforation of the mucous membrane during the sinus lift operation impaired bone tissue regeneration.
The obtained results suggest that the most promising way to close a bone defect in the anterior wall of the maxillary sinus is the use of a collagen membrane; therefore, we recommend choosing this approach for sinus lift surgery.

In the posterior maxilla, due to the presence of maxillary sinus, residual bone height lower than 3mm is a critical factor that can affect implant stability and survival. The use of guided surgery may facilitate the surgical procedures and the implant insertion in case of severely resorbed maxillae. Moreover, it may have beneficial effects on the long-term survival and success of implant-supported restorations. This study aimed to evaluate implant supported restorations on severely resorbed maxilla (<3 mm) after sinus lift with collagenated xenograft and guided surgery.
Forty-three patients with need for implant rehabilitation and residual bone height between 1 and 3 mm were recruited. Surgical and prosthetical aspects were planned following digital approach with the use of Realguide 5.0 (3diemme, Varese, Italy). Lateral window sinus lift was performed and implants were placed simultaneously to the augmentation procedure with a tooth-supported pilot drill surgical template. A pre-hydrated collagenated porcine bone matrix was adopted as regenerative material. Computer-aided-design/computer-aided-manufacturing (CAD/CAM) restorations were delivered after six months of healing. Milled titanium chamfer abutments with CAD/CAM crowns were used. Bone height at implant site level was measured using an image software analysis applied to the pre- and post-surgical radiographs and at the follow-up. Biological and technical complications were recorded during all the follow-up periods.
Fifty-four sinus were treated. After a mean follow-up time of 5.11 years (SD: 2.47), no implants were lost nor showed signs of disease. The mean pristine bone height was 2.07 mm (SD: 075). At the final evaluation the augmented sinus height was 12.83 mm (SD: 1.23). Two cases experienced minor perforation of the membrane, while five patients developed minimal post-operative complications, completely resolved with pharmacologic therapy. No mid-term biological complications were experienced by the patients. No cases experienced peri-implant mucositis and peri-implantitis during the whole follow-up period. Four patients (7.4%) faced an unscrewing of the prosthesis.
The present study showed the efficacy in the mid-term of the digital planning and the guided surgery in restoring severely resorbed posterior maxilla with dental implants.
This paper underlines the high potential of the digital approach in the mid-term to implant rehabilitation of severely resorbed maxilla simultaneously with sinus lift.

The goal of this systematic study was to compare the survival rate (SR), marginal bone loss (MBL) and clinical complications between extra-short implants (≤6 mm) and 6-mm-longer implants in randomized clinical trials. A systematic electronic and manual search was performed using the PubMed, Web of Science, Scopus and DOAJ databases. A meta-analysis was conducted to compare the SR and MBL between both groups. We have selected 17 studies out of 1016 articles for qualitative and quantitative analysis. The data from 956 patients and 1779 implants were used with an overall mean clinical follow-up of 3.88 years ranging from 1 to 8 years. Overall, the SR of extra-short implants (93.12%) was lower than the observed in 6-mm-longer implants (95.98%); however, there was no statistical significance on these findings (P > 0.10). MBL analysis showed that extra-short implants and the 6-mm-longer group presented an average of -0.71 and -0.92 mm after 1-year respectively. Three years follow-up showed MBL of -0.42 mm (≤6 mm) and -0.43 mm (>6 mm); 5 years follow-up showed an MBL of -0.69 mm (≤6 mm) and -0.46 mm (>6 mm); and after 8 years of follow-up, it was found an MBL of -1.58 mm (≤6 mm) and -2.46 mm (>6 mm). Within the limitation of this study, the results indicated that SR of extra-short implants was similar to 6-mm-longer implants. In contrast, MBL and the presence of clinical complications were observed at a lessened rate on extra-short implants.