[Deciphering the fate of granulation tissue in the human inflammatory alveolar microenvironment using single-cell RNA sequencing].

Objective: To investigate the cellular composition and heterogeneity of granulation tissue in human alveolar sockets and construct single-cell transcriptomic maps to elucidate the potential outcomes of natural resolution in the inflammatory microenvironment. Methods: Granulation tissues from 12 alveolar sockets undergoing tooth extraction due to periodontitis and scheduled for delayed site preservation or autologous tooth transplantation were collected in the Department of Oral and Maxillofacial Surgery, School of stomatology Fourth Military Medical University from September 2022 to August 2023. This study used HE staining and single-cell RNA sequencing (scRNA-seq) to observe the cellular composition and morphological changes of different types of granulation tissues. This approach enabled us to identify cellular sequence variations in the inflammatory dental alveolar granulation tissue within specific microenvironments, construct single-cell atlases for different types of human dental alveolar granulation tissues, and explore the spatiotemporal patterns of cell type distribution and key gene changes during the resolution process of inflammatory granulation tissue. Results: HE staining revealed extensive infiltration of inflammatory cells in the dental alveolar inflammatory granulation tissue. After allowing the inflammatory granulation tissue to naturally resolve for three weeks, its histological morphology was essentially consistent with that of reparative granulation tissue. ScRNA-seq captured a total of 20 448 cells from granulation tissues, and the gene expression quantification analysis revealed total gene counts of 33 835 for inflammatory granulation tissue, 36 058 for naturally resolved granulation tissue, and 34 719 for reparative granulation tissue. At the single-cell level, granulation tissue was annotated into ten cell subgroups, including vascular endothelial cells, mesenchymal stem cells, and fibroblasts. Differences were observed in the proportion of cell compositions between inflammatory and naturally resolved granulation tissues. Pseudo-temporal analysis illustrated two main outcomes in tissue resolution and healing, involving immune responses and angiogenesis. Among these, genes associated with inflammation regulation and immune response, such as Igbp5, Zfp36, and Hspa1b, as well as genes involved in extracellular matrix secretion and the formation of vessels and fibers such as Timp3, Postn, and Rgs5, showed significant differences in expression between the two types of granulation tissues. Conclusions: Inflammatory granulation tissue exhibits heterogeneity in cell composition, gene expression, and biological functions compared to naturally resolved granulation tissue. When the inflammatory granulation tissue in the alveolar socket is left undisturbed to undergo natural resolution, it displays a cellular composition similar to that of reparative granulation tissue at both the histological and single-cell levels. Moreover, it modulates the inflammatory response and the healing process through immune reactions and tissue remodeling.

[Strolling through the glorious years of Alveolar Surgery, bravely stepping onto the path of practice and innovation].

This article summarizes and organizes relevant publications in journals, along with a review of medical history, systematically summarizing the development process of dental alveolar surgery in China. The initial establishment phase (1935-1952) marked the starting point of Chinese Alveolar Surgery. Despite the impact of wars, it laid the foundation for subsequent research and practice. During the early development phase (1953-1966), the "Chinese Journal of Stomatology" was founded, which promoted the development of Alveolar Surgery. Research focused on tooth extraction methods and complications. Tooth Transplantation and Preprosthetic Surgery gradually began to take off. The stagnant phase (1967-1977) occurred due to the interruption of international exchanges, leading to an almost complete halt in the development of Alveolar Surgery. Entering the rapid catch-up phase (1978-1985), Alveolar Surgery scholars in China began striving to overcome the stagnation of the previous decade. While some progress was made, no significant innovative achievements emerged. In the scientific development phase (1986-2010), clinical research, basic experiments, and paper writing in modern Chinese Alveolar Surgery began to adhere to scientific standards with the rise of experimental medicine. The exploration and innovation stage (2011-2023) is the current development phase, during which Chinese Aveolar Surgery has reached its peak, making substantial progress in technology, clinical practices, and basic research, gradually reaching or even surpassing international advanced levels. Looking back at the development history in China, we can find the wisdom and hard work of the older generation of Alveolar Surgery scholars. However, contemporary challenges and issues, such as standardizing technology, promoting clinical practices, and talent cultivation, need to be addressed by present-day Alveolar Surgery professionals as they forge ahead.

Association between maximum mouth opening and area of bony fusion in simulated temporomandibular joint bony ankylosis.

The aim of this study was to investigate the quantitative association between active/passive maximum mouth opening (AMMO/PMMO) and the severity of simulated temporomandibular joint (TMJ) bony ankylosis. Twenty-eight male sheep were divided randomly and equally into surgical and control groups. Surgical group animals underwent bilateral TMJ osteotomy during which left lateral pterygoid muscle function was blocked. Control animals did not undergo surgery. Body weight, AMMO/PMMO, and TMJ morphological features were evaluated preoperatively and at 12 and 24 weeks post-surgery. In the surgical group, only the right TMJ complexes with maintained lateral pterygoid muscle function developed TMJ bony ankylosis. The AMMO/PMMO and end-feel distance in the surgical group were significantly lower than those in the control group (P < 0.001, both) at 12 and 24 weeks post-surgery. Moreover, AMMO (r = -0.940 and -0.952, P < 0.001, both) and PMMO (r = -0.944 and -0.953, P < 0.001, both) were negatively correlated with the area (mm2) of bony fusion post-surgery. These findings may be useful for the clinical treatment of early mandibular condyle fracture, with the use of occlusal pads/open-mouth plates to relax the lateral pterygoid muscle and block its function. When bony ankylosis developed in the TMJ, the greater the area of bony fusion, the more limited were AMMO/PMMO.

The lateral pterygoid muscle affects reconstruction of the condyle in the sagittal fracture healing process: a histological study.

The purpose of this study was to verify the role of the lateral pterygoid muscle in the reconstruction of the condyle shape during the sagittal fracture healing process by histological methods. Twenty-four adult sheep underwent an osteotomy to create a sagittal fracture of the left condyle; the sheep were then divided randomly into two groups. The lateral pterygoid muscles of the sheep in the experimental group were maintained on the internal poles of the condyles, and their functions remained stable. The lateral pterygoid muscles of the sheep in the control group were cut, and their functions were blocked. The shape, erosion, and calcification of the condyles were observed and measured after 4, 12, and 24 weeks of healing (n=4 from each group). The condyles were then submitted to haematoxylin and eosin, Ponceau S, and Sirius red studies. The results of the histology studies showed increased bone formation in the experimental group in which the functions of the lateral pterygoid muscle remained the same. The results of this study suggest that the lateral pterygoid muscle affects the reconstruction of the condylar shape during the healing process of a sagittal fracture of the mandibular condyle, and may even be involved in the formation of ankylosis.

Use of a temporary screw for alignment and fixation of sagittal mandibular condylar fractures with lateral screws.

This study introduced and evaluated the clinical application of a temporary and lateral screw technique for open reduction and internal rigid fixation of sagittal mandibular condylar fractures. A preauricular approach was used to expose the fracture. A temporary screw was used to assist in the anatomical reduction, and a lateral lag screw in combination with a lateral position screw was used for internal rigid fixation. Six adult patients with sagittal condylar fractures and more than 5mm condylar height shortening were treated. The treatment outcomes were followed up clinically and radiographically for 8-27 months (mean 18 months) postoperatively. There were no complications associated with the operation. All patients recovered favorably with good occlusion, normal movement of the mandible, correct repositioning and rigid fixation of the fragment of the fracture and a good condyle shape on radiographs. The temporary and lateral screw technique is a simple, effective, fast, and minimally invasive surgical treatment for adult sagittal condylar fractures.

Diagnosis and surgical treatment of carotid body tumors: 25 years' experience in China.

Carotid body tumors (CBT) are rare neoplasms arising from the small chemoreceptor organ in the adventitia of the common carotid bifurcation. A retrospective survey was conducted in 33 patients, treated by curative resection of the neoplasm, from 1980 to 2005, to investigate clinical features, preoperative treatment and surgical approach, and determine the optimum management for CBT. The demographic characteristics, clinical features, surgical approach and complications were documented and analyzed. Accurate diagnosis and effective preoperative training were associated with a good surgical outcome. Carotid arteriography accurately diagnoses and evaluates the brain's collateral circulation in the circle of Willis. Ultrasonography is useful. Carotid blood flow obstruction (Matas' training) is effective. Complete excision of the carotid system without a vascular replacement is possible only after reliable Matas' training and objective observation of the establishment of circulation in the circle of Willis. Correct treatment of the internal and common carotid artery is important to reduce postoperative complications. The continuity of the common and internal carotid artery should be retained if possible, and carotid artery repair is recommended. Minor complications occurred in five (15%) patients and one patient died from a cause not related to the CBT at follow-up.