Digitally designed stent-assisted soft-tissue management after jaw reconstruction: a prospective cohort study.

OBJECTIVES: A digitally designed stent was invented to assist vestibuloplasty and free gingival graft (FGG) after jaw reconstruction. This study aimed to compare the effects of conventional soft-tissue management comprising vestibuloplasty combined with FGG and modified soft-tissue management using a digitally designed stent on the vestibular sulcus depth (VD), keratinised-tissue width (KTW) and peri-implant tissue health in patients undergoing jaw reconstruction. MATERIALS AND METHODS: This prospective cohort study enrolled patients who underwent jaw reconstruction using a fibular flap, iliac flap, or onlay bone graft followed by implant-supported rehabilitation at the Peking University School and Hospital of Stomatology between May 2019 and July 2022. Patients in the stent group received digitally designed stents following vestibuloplasty combined with FGG for peri-implant soft-tissue management. Patients in the control group underwent a conventional vestibuloplasty combined with FGG. VD and KTW were evaluated immediately after implant loading (T2) and 1 year after implant loading (T3), and the atrophy rates of VD and KTW were calculated. Peri-implant clinical parameters were evaluated at T3. Comparisons between the groups were performed using the Mann-Whitney U test. The effects of age, sex, primary disease, reconstruction type, reconstructed jaw and the number and location of implants on VD and KTW were evaluated using linear regression analysis. RESULTS: There were no significant differences in the atrophy rates of VD and KTW between the stent and control groups at T2 and T3 (both P ≥ 0.05). There were no significant differences in peri-implant clinical parameters between the stent and control groups at T3 (P ≥ 0.05). Reconstruction type, location of implants and primary disease influenced VD, and reconstruction type and age influenced KTW. CONCLUSIONS: There was no significant difference in the maintenance of VD and KTW after jaw reconstruction between soft-tissue management using a digitally designed stent and the conventional method. Further, digitally designed stents do not affect peri-implant tissue health. CLINICAL RELEVANCE: Digitally designed stents can simplify clinical procedures without adverse effects on peri-implant tissue health, but they do not promote keratinized mucosa augmentation and vestibuloplasty.

Association between periodontitis and COVID-19 infection: a two-sample Mendelian randomization study.

Background and Objective: Epidemiological studies report associations between coronavirus disease 2019 (COVID-19) and periodontitis; however, causality has not been proven. The aim of this study is to assess the associations between COVID-19 susceptibility and periodontitis with two-sample Mendelian randomization (MR) analyses. Methods: A two-sample summary MR analysis was performed using data for outcome and exposure from the OpenGWAS database on people of European descent. Periodontal complex traits (PCTs) were chosen as a proxy for the periodontitis phenotype. The causal association between PCT3 (Aggregatibacter actinomycetemcomitans), PCT5 (Porphyromonas gingivalis), and gingival crevicular fluid (GCF) interleukin-1ß (IL-1ß) and COVID-19 were considered. Genome-wide association study (GWAS) data with the two largest sample sizes were selected as COVID-19 outcomes (datasets ebi-a-GCST010776 and ebi-a-GCST010777). Single-nucleotide polymorphisms (SNPs) associated with PCT3, PCT5, and GCF IL-1ß at statistical significance at genome-wide level (P < 5 × 10-8) were identified as genetic instruments. We used two-sample summary MR methods and tested the existence of a pleiotropic effect with MR-Egger. Results: Inverse-variance weighted (IVW) estimates showed that there was a positive association between COVID-19 risk and periodontitis (ebi-a-GCST010776: odds ratio [OR] = 1.02 (95% confidence interval (CI), 1.00-1.05), P = 0.0171; ebi-a-GCST010777: OR = 1.03 (95% CI, 1.00-1.05), P = 0.0397). The weighted median also showed directionally similar estimates. Exploration of the causal associations between other PCTs and COVID-19 identified a slight effect of local inflammatory response (GCF IL-1ß) on COVID-19 risk across the two datasets (ebi-a-GCST010776: IVW OR = 1.02 (95% CI, [1.01-1.03]), P < 0.001; ebi-a-GCST010777: IVW OR = 1.03 (95% CI, [1.02-1.04]), P < 0.001). The intercepts of MR-Egger yielded no proof for significant directional pleiotropy for either dataset (ebi-a-GCST010776: P = 0.7660; ebi-a-GCST010777: P = 0.6017). Conclusions: The findings suggests that periodontitis and the higher GCF IL-1ß levels is causally related to increase susceptibility of COVID-19. However, given the limitations of our study, the well-designed randomized controlled trials are needed to confirm its findings, which may represent a new non-pharmaceutical intervention for preventing COVID-19.

Superwettable and injectable GelMA-MSC microspheres promote cartilage repair in temporomandibular joints.

Temporomandibular disorders (TMD) can be treated by promoting cartilage regeneration with biomaterials. However, there are deficiencies in the infiltration function of bone filler biological materials. In this study, stems cells were loaded onto gelatin methacryloyl (GelMA) hydrogel microspheres endowed with superwettable properties and TGF-ß sustained-release function, which can quickly infiltrate the irregular surface of the temporomandibular joint (TMJ) bone defect area and accelerate cartilage healing. First, to improve cell adhesion and spreading function, the BMSCs-coated GelMA microspheres were endowed with superwetting property. At the same time, the swelling adsorption characteristics of gelatin microspheres could be used to load recombinant TGF-ß within the microspheres, which could in turn promote the chondrogenic differentiation of multi-potent bone marrow mesenchymal stem cells. The SEM imaging demonstrated that BMSCs-coated GelMA microsphere has superwettable and superhydrophilic property, which enabled rapid adaptation to the bone defect surface morphology, which is conducive to tissue repair. Furthermore, the cartilage defect model showed that rBMSCs-coated GelMA microspheres promote temporomandibular joint arthritis repair. In conclusion, our study established that BMSC-coated GelMA microspheres endowed with superwetting properties, can colonize the bone defect repair site better with sustained release of growth factors, thus providing an innovative strategy for promoting cartilage regeneration.

Accuracy of additive manufacturing in stomatology.

With the rapid development of the three-dimensional (3D) printing technology in recent decades, precise and personalized manufacturing has been achieved gradually, bringing benefit to biomedical application, especially stomatology clinical practice. So far, 3D printing has been widely applied to prosthodontics, orthodontics, and maxillofacial surgery procedures, realizing accurate, efficient operation processes and promising treatment outcomes. Although the printing accuracy has improved, further exploration is still needed. Herein, we summarized the various additive manufacturing techniques and their applications in dentistry while highlighting the importance of accuracy (precision and trueness).

Accurate Reconstruction of Mandibular Defects With Vascularized Bone Flaps Through Utilization of Mandible Space-Retention Guides.

PURPOSE: Comprehensive evaluation of the effects of using computer-aided design and space retention guide technology to reconstruct mandibular defects using vascularized autogenous bone flaps. METHOD: This study included 8 patients who received autogenous bone flaps (2 cases of vascularized fibula flaps and 6 cases of vascularized iliac flaps) for mandibular defect reconstruction at Peking University School and Hospital of Stomatology, from July 2018 to May 2021. All patients received digital surgery planning, computer aided design/computer aided manufacture, surgical guide technique for the removal of diseased bone segments, as well as vascularized fibular flap/iliac flap reconstruction. Three-dimensional deviations were analyzed after the operation. RESULT: The mandibular defects of all 8 patients were successfully reconstructed using the vascularized fibular flap/iliac bone flap. There were no serious complications at either the donor site or recipient site during our follow-up. The average three-dimensional deviation of all 8 patients was 1.92 mm, based on comparisons of preoperative design and actual postoperative computed tomography. CONCLUSION: Utilizing computer aided design/computer aided manufacture, we designed a new mandibular space-retention guide, which can accurately translate the preoperative digital design plan to real-time surgery with satisfactory accuracy and efficacy.

Soft Tissue Management: A Critical Part of Implant Rehabilitation After Vascularized Free-Flap Reconstruction.

PURPOSE: Implant rehabilitation after jaw reconstruction is challenging, and postoperative peri-implantitis is common. Our aim was to present our management protocol for implant rehabilitation after vascularized free-flap reconstruction and report the outcomes of soft tissue management. METHODS: This retrospective cohort study included patients who received vascularized free-flap reconstruction, implant rehabilitation, apical reposition flaps (ARFs), and free gingival grafts (FGGs) at Peking University School and Hospital of Stomatology from January 1, 2009 to January 1, 2020. We assessed the association of age, gender, primary disease, flap choice, number and position of implants, timing of ARFs and FGGs, fixation stent use, and restoration type with the occurrence of peri-implantitis. Probing pocket depth, bleeding on probing, and marginal bone loss of the implants were measured as well. The data were analyzed by descriptive statistics, Kaplan-Meier statistics, and Cox regression analysis. RESULTS: In total, 19 patients with 65 implants were included. The implants were placed immediately or 7 to 44 months after reconstruction of the jaw with fibular (n = 17) or iliac flaps (n = 2). ARFs and FGGs were performed 0 to 11 months later. No implants were lost. The mean probing pocket depth, bleeding on probing, and marginal bone loss at 26.6 ± 16.8 months were 3.5 ± 0.9 mm, 70.4 ± 35.1%, and 0.6 ± 0.4 mm, respectively. The incidence of peri-implantitis was 32.3%, showing no significant associations with the gender, age, primary disease, flap choice, number and position of implants, timing of ARFs and FGGs, use of a fixation stent, and type of restoration based on the adjusted multivariate model (P > .05). CONCLUSIONS: Soft tissue management helps generate firmly attached keratinized mucosa around the implants, leads to a more precise impression, and reduces peri-implant bone loss. It should be considered as a critical part of implant rehabilitation after vascularized free-flap reconstruction.