Biomechanical behavior of mandible with posterior marginal resection using finite element analysis

Evaluation of the effect of symphysis trauma on fracture pattern after marginal mandibular resection by finite element analysis

Mandibular fractures following marginal mandibular resection (MMR) remain an unresolved issue. The aim of this study is to determine the regions where stresses are likely to concentrate following trauma to the mandible after Marginal Mandibular Resection (MMR), and to identify the potential locations of postoperative fractures. Additionally, the study aims to establish the minimum bone height that can best resist trauma, with the goal of reducing fracture incidence. Using finite element analysis (FEA), 13 mandibular models were created. MMR was performed with constant mesiodistal diameters but increasing vertical resection heights by 5 mm increments. Seven resections were made in the symphysis and six in the body. A force of 1000 N was exerted to the symphysis. The von Mises (VM), maximum principal (Pmax), and minimum principal (Pmin) stress values were evaluated. The results showed that a residual bone height of 18 mm or less in the symphysis and 17 mm or less in the body leads to fractures under trauma. Residual bone height is a critical factor in preventing iatrogenic fracture following MMR. If insufficient bone height remains after MMR, prophylactic internal fixation should be considered to prevent fractures.

Mapping the research landscape on temporomandibular disorders and orthodontics treatment: A bibliometric analysis

BACKGROUND

Temporomandibular disorders (TMD) and orthodontic treatment are significant areas within dental and maxillofacial research. However, comprehensive bibliometric analyses highlighting global trends and collaboration networks are lacking.

OBJECTIVE(S)

This study aims to systematically map the publication landscape, identify prevailing research trends, highlight influential authors and institutions, and illuminate emerging topics in TMD and orthodontic research.

METHODS

Publications concerning TMD and orthodontic treatment from 2000 to 2024 were retrieved from the Web of Science Core Collection. A bibliometric analysis was conducted using VOSviewer, CiteSpace, and R to evaluate co-authorship networks, institutional collaborations, and keyword co-occurrence patterns.

RESULTS

A total of 871 publications were identified, with an average annual growth rate of 4.4 %. Contributions came from 47 countries and involved 3,463 authors, with the USA and Japan leading in citations. Notable institutions included Kyung Hee University and Baylor University. Key journals included the American Journal of Orthodontics and Dentofacial Orthopedics and the Journal of Oral and Maxillofacial Surgery. Frequently occurring keywords were "temporomandibular-joint," "orthognathic surgery," and "orthodontic treatment," indicating essential research foci. Emerging trends highlighted advancements in surgical techniques and technological innovations in orthodontics.

CONCLUSION

This bibliometric analysis offers valuable insights into global research trends and hotspots in TMD and orthodontic treatment, emphasizing the collaborative nature of the field and illuminating emerging areas for future investigation.

Current global research on mandibular defect: A bibliometric analysis from 2001 to 2021

Background: Mandibular defects can result from congenital deformities, trauma, tumor resection, and osteomyelitis. The shape was irregular because the lower jaw was radians. This involves teeth and jaw functions; therefore, the difficulty of bone repair is greater than that in other body parts. Several standard treatments are available, but they result in various problems, such as difficulties in skin flap transplantation and possible zone dysfunction, artificial material boneless combining ability, and a long treatment period. This study aimed to introduce the present status of research on mandibular defects to analyze the current introduction and predict future research trends through a bibliometric study. Methods: From 2001 to 2021, publications on mandibular defects were collected for bibliometric visualization using VOSviewer, CiteSpace, and Scimago Graphica software based on the Web of Science Core Collection. Results: This study analyzed 4,377 articles, including 1,080 published in the United States, 563 in China, and 359 in Germany, with an increase in the number of articles published over the past 20 years. Wikesjoe and Ulf Mai E had the most publications (p = 36) and citations (citations = 1,553). Shanghai Jiaotong University published the highest number of papers among the research institutions (p = 88). The most productive journal was Journal of Oral and Maxillofacial Surgery, and the cited literature was primarily classified as dentistry, dermatology, and surgery. Cluster Analysis of Co-occurrence Keywords revealed that highest number of core words were mandibular defects, mandibular reconstruction, and bone regeneration. The highest cited words were head and neck cancer, accuracy, and osteogenic differentiation. High-frequency terms of Cluster Analysis of References were osteosynthesis plate, tissue engineering, and rapid distraction rate. Conclusion: Over the past 20 years, the number of studies on mandibular defects has gradually increased. New surgical procedures are increasingly being used in clinical practice. Current frontier topics mainly focus on areas such as computer-aided design, 3D printing of osteotomy and reconstruction guide plates, virtual surgical planning, and bone tissue engineering.

Comparative evaluation of a patient-specific customised plate designs and screws for partial mandibular reconstruction

Mandibles with odontogenic tumors are often partially reconstructed with a metallic bone graft analogue with dental roots, crowns, along with a customized plate fixed with monocortical or bicortical screws, following resection of the tumor. In this study, two different designs of patient specific customized Ti reconstruction plates, solid and plate with holes, were considered. Fixation through both bicortical and monocortical screw types were investigated. FE models of the reconstructed mandibles were developed to analyse the influence of the plate-screw type combination on the load transfer across the mandibles under a mastication cycle. The effective homogenized orthotropic material properties of the lattice structures with 0.6 mm fibre diameter with 0.5 mm inter-fibre space were assigned to material properties for the bone graft analogue. The study shows that the combination of plate and screw types influences the state of stresses in the reconstructed mandible. Based on the results of this patient specific study, following resection of the tumor, either solid Ti plate with bicortical screws or Ti plate with holes along with monocortical screws may be used for partial mandibulectomy. It should also be noted that stresses in none of the plates or screws exceeded the yield limit for Ti under the mastication cycle indicating that the components are safe for mandibular reconstruction. However, the choice of this combination of reconstruction plates and screws is dependant on the condition and severity of the tumor in the diseased mandible.