3D-printed bredigite scaffolds with ordered arrangement structures promote bone regeneration by inducing macrophage polarization in onlay grafts

Bone tissue engineering scaffolds may provide a potential strategy for onlay bone grafts for oral implants. For determining the fate of scaffold biomaterials and osteogenesis effects, the host immune response is crucial. In the present study, bredigite (BRT) bioceramic scaffolds with an ordered arrangement structure (BRT-O) and a random morphology (BRT-R) were fabricated. The physicochemical properties of scaffolds were first characterized by scanning electron microscopy, mechanical test and micro-Fourier transform infrared spectroscopy. In addition, their osteogenic and immunomodulatory properties in an onlay grafting model were investigated. In vitro, the BRT-O scaffolds facilitated the macrophage polarization towards a pro-regenerative M2 phenotype, which subsequently facilitated the migration and osteogenic differentiation of bone marrow-derived mesenchymal stem cells. In vivo, an onlay grafting model was successfully established in the cranium of rabbits. In addition, the BRT-O scaffolds grafted on rabbit cranium promoted bone regeneration and CD68 + CD206 + M2 macrophage polarization. In conclusion, the 3D-printed BRT-O scaffold presents as a promising scaffold biomaterial for onlay grafts by regulating the local immune microenvironment.

Vertical ridge augmentation of atrophic posterior mandible with corticocancellous onlay symphysis graft versus sandwich technique: clinical and radiographic analysis

Alveolar ridge augmentation of atrophic posterior mandibular ridge represents a challenge in oral and maxillofacial surgery to restore aesthetic and function. The aim of the study was to compare the clinical and radiographic outcomes of bone formation in atrophic posterior mandibles augmented using onlay symphysis cortico-cancellous bone block with that augmented using sandwich bone augmentation technique (Inlay). Twelve patients were selected with missing mandibular posterior teeth. CBCT were done for all patients preoperatively to assess the residual bone height, ranged between 5 and 7 mm from the inferior alveolar nerve with adequate sufficient alveolar ridge width more than 4 mm. Patients required bone augmentation procedure with autologous onlay chin graft (group I) versus those used as inlay sandwich technique (group II). Clinical and radiographic analysis were done to analyses the newly formed bone and bone height. Percent of change in bone height was also calculated and revealed that group I was higher than group II, however, statistically insignificant differences between the two groups were found regarding the percentage of newly formed bone. Vertical ridge augmentation procedures using onlay chin graft took lesser time than the interpositional grafting with fixation technique, however, both techniques are promising for vertical ridge augmentation.

Secondary correction of nasal deformities in cleft lip patients using acellular dermal matrix grafting on the nasal tip with open rhinoplasty

Secondary nasal deformities in patients with unilateral cleft lip represent surgical challenges. Open rhinoplasty involving repositioning of the lower lateral cartilage has been shown to be a suitable technique for patients with cleft lip and nose deformities. This study aimed to explore a particular method of rhinoplasty and to assess the aesthetic outcomes for secondary unilateral cleft lip and nose deformities following its use. Fifty-seven patients treated for secondary unilateral cleft lip nasal deformities from January 2012 to December 2018 were enrolled in the study. Open rhinoplasty combined with a reverse-U incision and acellular dermal matrix grafting on the nasal tip was performed in all patients by the same surgeon. In our follow-up study we evaluated the results by measuring angles on photographs and scoring the appearance before and after operation. Data were statistically analysed using the t test. Appearances were improved in all patients. Both the alar base-nasal tip-columellar base angle and the nostril axis angles were smaller postoperatively (p < 0.001). According to the outcome scores, most patients (53/57) agreed that there was an obvious improvement in the appearance of their noses following surgery, and overall they were satisfied with the results of the revision procedure. A distinct improvement in nasal appearance can be achieved with this rhinoplasty. Our surgical method is effective and reliable in patients with secondary unilateral cleft lip and nose deformities, and is worth promoting in the clinic.

Economizing the Septal Cartilage for Grafts During Rhinoplasty, 40 Years' Experience

BACKGROUND

During rhinoplasty, it is typically necessary to use cartilage to shape and support the final nasal construct to provide both form and function to the nose (Tanna et al. in Plast Reconstr Surg 141(1):137e-151e, 2018; Guyuron in Plast Reconstr Surg 105(6):2257-2259, 2000; Kim et al. in Ann Plast Surg 65(6):519-523, 2010). The septal cartilage is the ideal graft both for its ease of access and quality of cartilage. However, this graft is a limited resource, and economy of its use is important as to negate the need to harvest cartilage from the ear or rib.

THE PURPOSE

1. To share the senior author's 40 years' experience with the economy of septal cartilage. 2. To identify the areas of the septal cartilage most suitable for a particular graft. 3. To discuss the common grafts that are used in rhinoplasty. 4. To identify when other sources of cartilage are needed and where to best use those grafts. 5. To present option for preservation of the leftover septal cartilage.

CONCLUSION

Overall consideration should focus on the size, thickness, and curvature of the graft contemplating the structural and functional needs of the rhinoplasty maneuvers.

LEVEL OF EVIDENCE V

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Resorption of retromolar bone grafts after alveolar ridge augmentation-volumetric changes after 12 months assessed by CBCT analysis

In this pilot study, a volumetric analysis of retromolar onlay bone grafts over a period of 12 months was conducted, using repeated CBCT imaging combined with automated image registration.

Eleven patients being treated with 16 bone grafts taken from the retromolar area were examined by CBCT scanning prior to bone augmentation (T0), immediately after bone augmentation (T1) and after a healing time of 12 months after augmentation (T2). Graft volumes were measured at each time point after automated image registration of consecutive CBCT scans.

The mean volume of the augmented site was 372.2 ± 179.4 mm³. Resorption relative to the original augmented volume was 43.7% ± 19.0% after 12 months.

Three-dimensional graft resorption could be precisely depicted by the use of automated image registration for CBCT data over a period of 12 months and demonstrated extensive volumetric changes of bone grafts taken from the ascending ramus of the mandible.

Graft resorption and continuous bony remodeling of the grafted site before and after implant insertion have to be carefully considered by the clinician.

Correction of secondary unilateral cleft lip nasal deformity in adults using lower lateral cartilage repositioning, columellar strut, and onlay cartilage graft on the nasal tip with open rhinoplasty combined with reverse-U incision

A rhinoplasty technique involving lower lateral cartilage (LLC) repositioning and grafting of ear cartilage allows for nasal lengthening and nasal tip mobility. For better esthetic outcomes in patients with cleft lip nasal deformity (CLND), we combined cosmetic nasal tip plasty with standard techniques. We performed open rhinoplasty combined with reverse-U incision and V-Y plasty in 62 patients with secondary unilateral CLND from October 2013 to June 2018. Both LLCs were isolated, repositioned, approximated medially, and advanced with a Medpor strut, followed by tip suture technique. To further project and enhance the nasal tip and columella, application of ear cartilage onlay graft was used. As adjunctive procedures, septoplasty or osteotomy was carried out for correction of septal or nasal bone deviations, respectively. Photogrammetric evaluations of patients and statistical analyses were performed. Average age at operation was 23.5 years (range: 18-42 years). Of the 62 patients, 15 underwent dorsal augmentation with silicone implant. Two-layer conchal cartilage onlay grafting was performed to manage tip height. Outcomes in 34 patients were analyzed with pre- and postoperative photography. Nasal tip projection increased, alar base width index decreased, and alar and columellar symmetry significantly improved. No Medpor implant exposure or other adverse outcomes occurred. The proposed technique is effective for correcting secondary unilateral CLND and achieving a satisfying nasal appearance in adults.

Effects of block bone substitutes loaded with Escherichia Coli-produced recombinant human bone morphogenetic protein-2 on space maintenance and bone formation in rat calvarial onlay model

We aimed to evaluate the effects of onlay-type grafted human freeze-dried corticocancellous bone block (FDBB) and deproteinized bovine bone with collagen (DBBC) loaded with Escherichia coli-produced recombinant human bone morphogenetic protein-2 (ErhBMP-2) on space maintenance and new bone formation in rat calvaria. Collagen sponge (CS), FDBB, or DBBC disks (8×4 mm) with ErhBMP-2 (2.5 μg) were implanted onto the calvaria of male Sprague-Dawley rats, whereas CS with buffer was implanted onto the calvaria as controls (n=20/carrier). Rats were killed at 2 or 8 weeks post-surgery for histologic and histomorphometric analyses; total augmented area, new bone area, and bone density were evaluated. At both time-points, all ErhBMP-2 groups showed significantly higher new bone area and bone density than the control group (p<0.05). ErhBMP-2/FDBB and ErhBMP-2/DBBC groups showed significantly higher total augmented area than ErhBMP-2/CS group (8 weeks), and ErhBMP-2/FDBB group showed significantly higher new bone area and bone density than ErhBMP-2/DBBC group (p<0.05). ErhBMP-2/CS group showed the highest bone density (p<0.05). Combining ErhBMP-2 with FDBB or DBBC could significantly improve onlay graft outcomes, by new bone formation and bone density increase. Moreover, onlay-grafted FDBB and DBBC with ErhBMP-2 could be an alternative to autogenous block onlay bone graft.

Histomorphometric evaluation of onlay freeze-dried block bone and deproteinized bovine bone with collagen in rat

The aim of this study was to evaluate the effect of human freeze-dried bone block (FDBB) and deproteinized bovine bone with collagen (DBBC) on bone formation when applied as an onlay graft in rat calvariums. Thirty male Sprague-Dawley rats received collagen sponge (control), FDBB, or DBBC onlay grafts trimmed into 8-mm disks measuring 4-mm height. Each graft was secured onto the calvarium surface using horizontal mattress sutures. Rats in each group were killed at 2 (n=5) or 8 (n=5) weeks postoperatively for histologic and histomorphometric analysis. The total augmented area (mm²), new bone area (mm²), and bone density (%) were measured. The FDBB and DBBC groups showed significantly more new bone formation and bone density than the control group at 2 and 8 weeks. The increased new bone area was significantly greater in the FDBB group than in the DBBC group (p<0.05). The total augmented area was significantly higher in the FDBB and DBBC groups at 2 and 8 weeks than in the control group (p<0.05), and at 8 weeks, the area was significantly decreased in the DBBC group compared to that in the FDBB group and the area at 2 weeks (p<0.05). Within the limitations of the present study, we concluded that onlay FDBB and DBBC grafts caused new bone formation through an osteoconductive mechanism. In addition, compared to FDBB, DBBC had less capacity to form new bone and maintain the space.