The performance tests of three-dimensional printing titanium alloy craniomaxillofacial bone plate: A preliminary preclinical study.

Background/purpose: Because of the complex anatomical structure of the maxillofacial skeleton, bending plates is necessary during surgery. The fast developing three-dimensional printing (3DP) technology has provided a new method for making personalized craniomaxillofacial bone plates. However, the properties of these bone plates remain unknown. This study evaluates the mechanical, fatigue, and morphological properties of these bone plates, which may provide data supporting future clinical applications. Materials and methods: The 3DP bone plate was fabricated by selective laser melting (SLM) and electron beam melting (EBM) technologies. Mechanical, surface, and defect analyses were performed to compare their properties with a standard machined sample. One-way analysis of variance was applied, with p < 0.05 considered significant. Results: The 3DP craniomaxillofacial bone plate had better bending strength than that of the standard machined plate (p < 0.01). Whereas the fatigue resistance of the 3DP bone plate needs to be improved in the future. Surface analysis indicated greater roughness of the 3DP bone plate (p < 0.01). However, the surface roughness could be significantly reduced by polishing the surface, which would meet the needs of clinical application after polishing. Further defect analysis revealed the internal defect inside the plate, which should be avoided to improve the mechanical strength of the printed sample in the future. Conclusion: The 3DP titanium craniomaxillofacial bone plate has good mechanical performance and surface morphology, meeting the requirements of clinical application. However, poorer fatigue resistance and a high number of internal defects should be modified in the future.

From "Empirical Surgery" to "Precision Surgery": establishment and clinical application of precision orthognathic surgery system.

Orthognathic surgery, which involve osteotomy and repositioning of the maxillomandibular complex, has recently emerged as a crucial method of correcting dentofacial deformities. The optimal placement of the maxillomandibular complex holds utmost significance during orthognathic surgery because it directly affects the surgical outcome. To accurately achieve the ideal position of the maxillomandibular complex, with the rapid advancements in digital surgery and 3D-printing technology, orthognathic surgery has entered an era of "Precision Surgery" from the pervious "Empirical Surgery." This article provides comprehensive insights into our extensive research and exploration of the treatment modality known as "precision orthognathic surgery" over the years. We also present the technical system and application in"Ortho+X" treatment modality to offer valuable references and assistance to our colleagues in the field.

Correction of narrow nostril deformity secondary to cleft lip: indications for different surgical methods and a retrospective study.

Background: Cleft lip and/or palate (CLP) can lead to severe nasolabial deformities that significantly affect the appearance of the patient. Among all types of nasolabial deformities, narrow nostril deformities are the most troublesome, causing poor and unstable surgical outcomes. The purpose of this study was to develop an algorithm for surgical method selection for revision of narrow nostril deformities secondary to CLP based on retrospective clinical data. Materials and methods: Patients with narrow nostril deformities secondary to CLP were enrolled in the study. Before surgery, patients' clinical data were collected and the width of the nasal floor and the length of the alar rim were measured. Surgical methods were determined according to the measurements. After surgery, a nostril retainer was applied for 6 months to consolidate and maintain the nostril shape. The surgical method and postsurgical changes were recorded for the final summary of the algorithm to select surgical methods for narrow nostril deformities. Results: The data from 9 patients were analyzed. According to the width of the nasal floor and the length of the alar rim, correct surgical methods were determined. Four patients received nasolabial skin flaps to widen the soft tissue of the nasal floor. Three patients received upper lip scar tissue flaps to treat the narrow nasal floor. For the short alar rim, free alar composite tissue flap or narrowing of the nostril of the noncleft side was recommended. Conclusion: The width of the nasal floor and the length of the alar rim are critical elements to consider when selecting the correct surgical method for revising narrow nostril deformities secondary to CLP. The proposed algorithm provides a reference for selecting surgical methods in future clinical practice.

A Proposal for the Classification of Temporomandibular Joint Disc Deformity in Hemifacial Microsomia.

Hemifacial microsomia (HFM) is the second most common congenital craniofacial disease and has a wide spectrum of symptoms. The classic diagnostic criterion for hemifacial microsomia is the OMENS system, which was later refined to the OMENS+ system to include more anomalies. We analyzed the data of 103 HFM patients with magnetic resonance imaging (MRI) for temporomandibular joint (TMJ) discs. The TMJ disc classification was defined into four types: D0 for normal disc size and shape; D1 for disc malformation with adequate length to cover the (reconstructed) condyle; D2 for disc malformation with inadequate length to cover the (reconstructed) condyle; and D3 for no obvious presence of a disc. Additionally, this disc classification was positively correlated with the mandible classification (correlation coefficient: 0.614, p < 0.01), ear classification (correlation coefficient: 0.242, p < 0.05), soft tissue classification (correlation coefficient: 0.291, p < 0.01), and facial cleft classification (correlation coefficient: 0.320, p < 0.01). In this study, an OMENS+D diagnostic criterion is proposed, confirming the conjecture that the development of the mandibular ramus, ear, soft tissue, and TMJ disc, as homologous and adjacent tissues, is affected to a similar degree in HFM patients.

Recent advances in smart stimuli-responsive biomaterials for bone therapeutics and regeneration.

Bone defects combined with tumors, infections, or other bone diseases are challenging in clinical practice. Autologous and allogeneic grafts are two main traditional remedies, but they can cause a series of complications. To address this problem, researchers have constructed various implantable biomaterials. However, the original pathological microenvironment of bone defects, such as residual tumors, severe infection, or other bone diseases, could further affect bone regeneration. Thus, the rational design of versatile biomaterials with integrated bone therapy and regeneration functions is in great demand. Many strategies have been applied to fabricate smart stimuli-responsive materials for bone therapy and regeneration, with stimuli related to external physical triggers or endogenous disease microenvironments or involving multiple integrated strategies. Typical external physical triggers include light irradiation, electric and magnetic fields, ultrasound, and mechanical stimuli. These stimuli can transform the internal atomic packing arrangements of materials and affect cell fate, thus enhancing bone tissue therapy and regeneration. In addition to the external stimuli-responsive strategy, some specific pathological microenvironments, such as excess reactive oxygen species and mild acidity in tumors, specific pH reduction and enzymes secreted by bacteria in severe infection, and electronegative potential in bone defect sites, could be used as biochemical triggers to activate bone disease therapy and bone regeneration. Herein, we summarize and discuss the rational construction of versatile biomaterials with bone therapeutic and regenerative functions. The specific mechanisms, clinical applications, and existing limitations of the newly designed biomaterials are also clarified.

Randomized Clinical Trial of the Accuracy of Patient-Specific Implants versus CAD/CAM Splints in Orthognathic Surgery.

BACKGROUND: The maxilla position is essential for the aesthetic and functional outcomes of orthognathic surgery. Previous studies demonstrated the advantages of patient-specific implants in orthognathic surgery. However, more data are needed to confirm the superiority of patient-specific implants over surgical splints created with computer-aided design/computer-aided manufacturing (CAD/CAM). This randomized controlled trial aimed to compare the accuracy of patient-specific implants and CAD/CAM splints for maxilla repositioning in orthognathic surgery. METHODS: Patients (n = 64) who required orthognathic surgery were randomly assigned to use either patient-specific implants (patient-specific implant group) or CAD/CAM surgical splints (splint group) to reposition the maxilla. The outcome evaluation was completed by comparing virtual plans with actual results. The primary outcome was the discrepancies of the centroid position of the maxilla. Other translation and orientation discrepancies of the maxilla were also assessed. RESULTS: The authors analyzed 27 patients in the patient-specific implant group and 31 in the splint group. The maxilla position discrepancy was 1.41 ± 0.58 mm in the patient-specific implant group and 2.20 ± 0.94 mm in the splint group; the between-group difference was significant (p < 0.001). For the patient-specific implant group, the largest translation discrepancy was 1.02 ± 0.66 mm in the anteroposterior direction, and the largest orientation discrepancy was 1.85 ± 1.42 degrees in pitch. For the splint group, the largest translation discrepancy was 1.23 ± 0.93 mm in the mediolateral direction, and the largest orientation discrepancy was 1.72 ± 1.56 degrees in pitch. CONCLUSION: The result showed that using patient-specific implants in orthognathic surgery resulted in a more accurate maxilla position than CAD/CAM surgical splints. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, I.

Does Nasal Cavity Enlargement Associated With Respiratory Function Improvement After Surgically Assisted Rapid Maxillary Expansion?

PURPOSE: To systematically evaluate the effects of surgically assisted rapid maxillary expansion (SARME) on nasal cavity and its associated respiratory function changes. MATERIAL AND METHODS: Multiple electronic databases were searched, authors were contacted as required, and reference lists of potentially relevant studies were screened. Articles that included patients older than 16 who had received SARME were considered. Data extraction and quality assessment were performed independently and in duplicate. RESULTS: Eight articles, including 161 patients, were finally selected and analyzed. Nasal cavity significantly augmentation after SARME has been recognized by 7 studies with moderate-quality evidence. Among them, the nasal cavity volume increased <20% in 4 studies, 20% to 40% in 1 study, and >40% in 2 studies. Totally, the range of increasing in nasal cavity volume was 7.6% to 99%. One study had recorded the nasal expiratory and inspiratory flow significantly increased 18.5% and 21.7%, respectively. CONCLUSION: SARME was found to produce meaningful volume augmentation in nasal cavity with adult patients. However, the improvement of nasal respiratory function has not been well elucidated; thus, SARME is not yet recommended for the purpose of improving nasal respiratory.

Surgery-first/early-orthognathic approach may yield poorer postoperative stability than conventional orthodontics-first approach: a systematic review and meta-analysis.

OBJECTIVE: There are conflicting views on the postoperative stability of surgery-first and surgery-early approaches in orthognathic surgery. We systematically reviewed the literature to compare the difference in postoperative stability between a surgery-first/early orthognathic approach (SFEA) and a conventional orthodontics-first approach (COA). STUDY DESIGN: PubMed, Embase, and Cochrane Library were searched for studies related to the postoperative stability of SFEA. The primary outcome was the horizontal relapse at the pogonion. Weighted mean differences with 95% confidence intervals were pooled using a random-effects model. RESULTS: We analyzed 12 studies (total of 498 participants). The pooled estimate suggested that the SFEA group manifested less postoperative stability than COA group (weighted mean difference, 1.50; P < .00001), with moderate heterogeneity (I2 = 53%). The result of subgroup analysis yielded no subgroup difference. Sensitivity analysis conducted by omitting one study at a time further validated the robustness of the result. CONCLUSIONS: Based on the meta-analysis, the mandible tends to rotate counterclockwise more in the SFEA group, which indicate a poorer postoperative stability than in the COA group. Patient screening and treatment plans should be reviewed carefully to compensate for possible postoperative relapse when adopting SFEA.

Application of A Novel Three-dimensional Printing Genioplasty Template System and Its Clinical Validation: A Control Study.

The purpose of this control study was to assess the accuracy and clinical validation of a novel genioplasty template system. Eighty-eight patients were enrolled and divided into 2 groups: experimental group (using genioplasty templates) and control group (without genioplasty templates). For the experimental group, the templates were designed based on computerized surgical plan and manufactured using three-dimensional printing technique. The template system included a cutting guide and a pair of repositioning guides. For the control group, traditional intraoperative measurements were used without genioplasty templates. The outcome evaluation was completed by comparing planned outcomes with postoperative outcomes. Linear and angular differences for the chin was measured and reported using root mean square deviation (RMSD) and the Bland-Altman method. All surgeries were successfully completed. There was no difficulty to use genioplasty templates. For the experimental group, the largest RMSDs were 1.1 mm in anteroposterior direction and 2.6° in pitch orientation. For the control group without templates, the largest RMSDs were 2.63 mm in superoinferior direction and 7.21° in pitch orientation. Our findings suggest that this genioplasty template system provides greater accuracy in repositioning the chin than traditional intraoperative measurements, and the computerized plan can be transferred accurately to the patient for genioplasty.