Background Earlier studies have not given clear results of concentrated growth factor (CGF) on gingival thickness (GT) in periodontal accelerated osteogenic orthodontics (PAOO). This randomized controlled trial aimed to evaluate the effects of CGF on GT in patients with thin gingival phenotype undergoing PAOO. Methods Forty four patients presenting 264 anterior mandibular teeth were recruited and randomly allocated to one of the groups: test—positioning of autologous CGF after PAOO or control—positioning of a collagen membrane after PAOO. GT, gingival height (GH), buccal alveolar bone thickness (BT), and buccal alveolar bone height (BH) were evaluated depending on cross-sectional CBCT images at t0 (before surgery) and t1(6 months after surgery). Results GT were increased in both groups at t1 compared to t0. Yet, higher values were observed in the test group (from 0.94 ± 0.23 to 1.31 ± 0.33 mm) compared to the control group (from 0.94 ± 0.19 to 1.02 ± 0.16 mm) (p < 0.05). Moreover, in the intergroup comparison, GT at t1 in the test group was significantly higher compared to the control group (p < 0.01). Furthermore, the GT of central incisors, lateral incisors and canine teeth all showed significantly changes compared with baseline and the test group showed higher increase (p < 0.01). No statistically significant difference were found in GH, BT, BH and all clinical parameters between two groups at t1 (p > 0.05). Conclusions Within the limitation of this study, gingival thickness could be increased by using CGF in PAOO for the patients with thin gingival phenotype. Trial registration The study was registered in Chinese Clinical Trial Registry (http://www.chictr.org.cn/index.aspx) under the number ChiCTRINR17013346, Registered 11 November 2017.

Background Mandibular condylar osteochondroma (OC) could lead to facial morphologic and functional disturbances, such as facial asymmetry, malocclusion, and temporomandibular joint dysfunction. However, after condylar OC resection, the inaccurate reposition of the neocondyle still needs to be solved. The purpose of this study was to explore the feasibility of the condylar osteotomy and repositioning guide to reposition the neocondyle in the treatment of patients with severe deformity secondary to condylar OC. Results Three patients with severe deformity secondary to OC of the mandibular condyle were enrolled in this study. With the aid of condylar osteotomy and repositioning guide, condylar OC resection and repositioning were carried out, and the accuracy and stability of these guides were evaluated. All patients healed uneventfully, and no facial nerve injury and condylar ankylosis occurred. Compared with the computerized tomography scans in centric relation before surgery and 3 days after surgery, the results showed that the facial symmetry was greatly improved in all the patients. Also, after the superimposition of the condylar segments before surgery and 3 days after surgery, the postoperative reconstructed condyles had a high degree of similarity to the reconstruction of the virtual surgical planning. Observed from the sagittal and coronal directions, the measurements of condylar positions were very close to those of virtual surgical planning. Moreover, it also showed stable results after a 1-year follow-up. Conclusions For patients with severe deformity secondary to condylar OC, condylar osteotomy, and repositioning guide was expected to provide a new option for the improvement of facial symmetry and occlusal relationship.