IntroductionMaxillary sinus augmentation is a widely used surgical procedure to increase the bone volume before implant placement. In order to predict the stability of the implant, analysis of the change in bone volume and quality after a sinus graft procedure is necessary. The purpose of this study was to analyze the change in volume and quality of bone graft material after maxillary sinus augmentation using cone beam computed tomography (CBCT).Methods and MaterialsMaxillary sinus lift procedures using bovine bone materials (Bio‐Oss, Geistrich, Swiss) without immediate implantation were performed at the Pusan National University Dental Hospital in 22 patients, from 2014 to 2017. CBCT images were captured before surgery (T1), a day after surgery (T2), and after 4 to 7 months at follow‐up (T3). The T2 and T3 images were registered to the T1 image using histogram matching and intensity‐based registration. A total of 30 sinuses were analyzed three‐dimensionally (3‐D), using self‐made software MATLAB 2018a (MathWorks, Natick, Massachusetts). The volume and structural indices of the bone graft material were measured and analyzed.ResultsThe average volume of graft material showed a decrease, while the average gray value showed an increase during the follow‐up period, but these changes were not statistically significant. The structural indices of the graft material after histogram matching showed a significant difference in homogeneity, connectivity, thickness, and roughness at the postoperative follow‐up.ConclusionsThe volume and gray value showed no statistically significant changes after the maxillary sinus lift procedures. The results of this study show that structural analysis using histogram matching can be used as a promising tool to analyze the quality of graft materials.

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Schneiderian membrane perforation (SMP) is the most common complication encountered during sinus lift procedures. SMPs should be managed to prevent loss of the valuable bone graft and bone substitute materials. A fast-resorbing collagen membrane (CM) is a soft, white, pliable, and nonfriable sponge used in dental surgery. The purpose of this study was to evaluate the clinical outcomes of SMP repair using CMs when an SMP had occurred during a sinus lifting procedure. The patients were divided into three groups according to the size of the SMPs during the sinus lift procedure. (A) Group 1: there was no perforation of the Schneiderian membrane but the membrane was weakened (or thinned) and repaired using CMs. (B) Group 2: the SMP was small to medium in size (< 10 mm) and repaired using CMs and fibrin adhesive (FA). (C) Group 3: the SMP was large in size (> 10 mm) and repaired using a collagen plug. The negative control group consisted of patients who did not have any SMP (Control) and these patients were randomly selected. Orthopantomographic X-rays taken before surgery, 2–3 days following surgery, and over 6 months after surgery (follow-up) were used to evaluate the acquired bone height according to groups. Bone heights were measured from the crestal bone at the planned implant placement sites. Clinical outcomes, including implant success and complications according to repair method, were also investigated. There was no significant difference in bone heights between the groups with the exception of group 3. The overall implant survival rate was 100% for implants placed in sinuses with frank SMPs or weakened sinus membranes. The CM is applicable for small-to-moderate perforations or sinus membranes which have been weakened or thinned during sinus lift procedures.

Objective: The purpose of this study was to evaluate delayed soft tissue changes of the maxilla-mandibular complex MMC using three-dimensional (3D) cone-beam computed tomography after clockwise repositioning orthognathic surgery. Methods: This study included 21 patients that underwent maxilla-mandibular complex clockwise rotational orthognathic surgery by 1 doctor from January 2015 to June 2019. Radiographic images (panorama, lateral cephalogram, posteroanterior view, and conebeam computed tomography) were taken and 3D analysis was performed using the Invivo 5 (Anatomage Inc, Santa Clara, CA) to acquire 3D images before surgery, immediately after surgery, at 6 months after surgery and 21 months after surgery. The 9 soft tissue landmarks were measured and compared in terms of postoperative changes in transverse, vertical, and anteroposterior directions. The points were at the outer commissure of the eye fissure (Exocathion; Exc_r, Exc_l), at the midline of both the nasal root and the nasofrontal suture, analogous to bony N (soft tissue nasion; N), the most prominent point on the nasal tip (Pronasale; Prn), the most lateral point in the curved baseline of each ala, indicating the facial insertion of the nasal wing base (Alare curvature; Ac_r, Ac_l), the most lateral point on the soft tissue contour of each mandibular angle (Soft tissue Gonion; Go_r, Go_l), and the most inferior midpoint on the soft tissue contour of the chin (soft tissue menton; Me). Results: The most prominent point of the nasal tip (Prn) moved 1.36 mm upward and 1.55 mm forward in the vertical and anteroposterior planes immediately after surgery. However, there were no significant changes in Ac_r and Ac_l even immediately after surgery. Both soft tissue gonions shifted downward and forward between immediately after surgery and 6 months after surgery. However, no significant change was observed in the value of any of the 9 soft tissue points between 6 months and 21 months after surgery (P value < 0.05). Conclusions: No significant changes were observed between 6 and 21 months after surgery, which suggests no delayed soft tissue changes occur in surgically treated patients after the resolution of surgically-related facial edema and swelling and postsurgical remodeling of hard tissue in overlying soft tissue.

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