[Application of 3D printing modified tooth-supported cyst plug in decompression of mandibular cystic lesions].

PURPOSE: To evaluate the application value of 3D printing modified dental support cyst plug in fenestration of large jaw cystic lesions. METHODS: Forty patients with mandibular cystic disease in Xuzhou Central Hospital from October 2019 to April 2021 were selected. They were randomly divided into experimental group(3D printing group) and control group (traditional plug group), with 20 cases in each group. All enrolled patients underwent preoperative digital modeling of cystic lesions of the jaw, obtained the cystic cavity volume data of preoperative lesions, designed the windowing site according to the plan and performed decompression for jaw cysts. Three days after surgery, the patient's postoperative CBCT and Oral-scan data in the experimental group was obtained, and a digitally modified tooth-supported cyst plug with porous column channel was designed, and titanium alloy material for 3D printing was selected. In the control group, the plug was manually molded by experienced physicians. The visual analogue scale(VAS) score of pain, retention, mechanical properties of the plug and its effect on the adjacent teeth were compared between the two groups during the process of model preparation, and the changes of the cyst volume 1, 3 and 6 months after operation were compared between the two groups. SPSS 25.0 software package was used for data analysis. RESULTS: Compared with the control group, the patients in the experimental group who made titanium alloy as printing material by digital impression complained more comfortable, and the mechanical strength and stability of the cyst plug were better than those in the control group(P＜0.05). There was no significant difference in retention between the two groups(P＞0.05). The reduction rate of cyst volume in the experimental group was significantly higher than that in the traditional plug group 3 and 6 months after operation(P＜0.05). CONCLUSIONS: The modified tooth-supported titanium alloy cyst plug with digital 3D printing has good mechanical properties and stability. It has little damage to the abutment and no lateral force, and has the advantages of precision, individualization and comfort. The improved irrigation and injection channel can fully flush the cavity and speed up the narrowing of the cyst and reduce the waiting time before the second operation, which is worth promoting in clinical practice.

[Effect of root canal wall moisture and filling techniques on the sealability of iRoot sp].

PURPOSE: To study the effect of root canal wall moisture and filling techniques on the sealability of iRoot sp. METHODS: Sixty-two undamaged extracted human single-rooted teeth with fully developed apex were selected and prepared by crown-down technique. Two teeth were selected randomly to observe dentin tubules, opening, the residual teeth were randomly assigned to 3 groups: group A (wet), group B (slightly moist),group C(dry).The roots were further divided into 4 subgroups, group a: iRoot sp sealer without a core material (bulk-fill); group b: iRoot sp sealer with single cone obturation techniques; group c: iRoot sp sealer with heated gutta-purcha vertical pressure; group d: iRoot sp sealer with cold gutta-percha lateral compression technique. Glucose microleakage were measured in each group by glucose oxidase method. The differences in distribution of each group were analyzed with SPSS 19.0 software package. RESULTS: Group A and group B always showed the maximum and minimum amount of glucose penetration in the whole experimental process, and the difference was statistically significant at 28d (P<0.05). Under the same degree of moisture of root canal wall, glucose leakage of subgroup Aa was significantly higher than that of subgroup Ab and Ac at 15 d; and significantly higher than Ab, Ac, Ad at 21 d and 28 d(P<0.05). In group B and C, the subgroups a, b, c, d had no significant difference from each other during the experimental process(P>0.05). CONCLUSIONS: iRoot sp sealer has the best sealing effect when root canals were slightly moist. When the root canal wall is completely dry or slightly moist, the sealability of iRoot sp bulk-fill is similar to that of iRoot sp sealer with gutta-percha filling technique.

Predicting biomaterial property-dendritic cell phenotype relationships from the multivariate analysis of responses to polymethacrylates.

Dendritic cells (DCs) play a critical role in orchestrating the host responses to a wide variety of foreign antigens and are essential in maintaining immune tolerance. Distinct biomaterials have been shown to differentially affect the phenotype of DCs, which suggested that biomaterials may be used to modulate immune response toward the biologic component in combination products. The elucidation of biomaterial property-DC phenotype relationships is expected to inform rational design of immuno-modulatory biomaterials. In this study, DC response to a set of 12 polymethacrylates (pMAs) was assessed in terms of surface marker expression and cytokine profile. Principal component analysis (PCA) determined that surface carbon correlated with enhanced DC maturation, while surface oxygen was associated with an immature DC phenotype. Partial square linear regression, a multivariate modeling approach, was implemented and successfully predicted biomaterial-induced DC phenotype in terms of surface marker expression from biomaterial properties with R(prediction)(2) = 0.76. Furthermore, prediction of DC phenotype was effective based on only theoretical chemical composition of the bulk polymers with R(prediction)(2) = 0.80. These results demonstrated that immune cell response can be predicted from biomaterial properties, and computational models will expedite future biomaterial design and selection.

Macrophage and dendritic cell phenotypic diversity in the context of biomaterials.

Macrophages (Mϕ) and dendritic cells (DCs) are critical antigen presenting cells that play pivotal roles in host responses to biomaterial implants. Although Mϕs have been widely studied for their roles in the inflammatory responses against biomaterials, the roles that DCs play in the host responses toward implanted materials have only recently been explored. DCs are of significant research interest because of the emergence of a large number of combination products that cross-traditional medical device boundaries. These products combine biomaterials with biologics, including cells, nucleic acids, and/or proteins. The biomaterial component may evoke an inflammatory response, primarily mediated by neutrophils and Mϕs, whereas the biologic component may elicit an immunogenic immune response, initiated by DCs involving lymphocyte activation. Control of Mϕ phenotypic balance from proinflammatory M1 to reparative M2 is a goal of investigators to optimize the host response to biomaterials. Similarly, control of DC phenotype from proinflammatory to toleragenic is of interest in vaccine delivery and tissue engineering/transplantation situations, respectively. This review discusses the interconnection between innate and adaptive immunity, the comparative and contrasting phenotypes and roles of Mϕs and DCs in immunity, their responses to biomaterials and the strategies to modulate their phenotype for applications in tissue engineering and vaccine delivery. Furthermore, the collaboration between and unique roles of DCs and Mϕs needs to be addressed in future studies to gain a more complete picture of host responses toward combination products.

Validation of a high-throughput methodology to assess the effects of biomaterials on dendritic cell phenotype.

A variety of combination products composed of biomaterials and biologics have been developed for tissue regeneration or vaccine delivery. The host immune response to the immunogenic biological components in such products may be modulated by the biomaterial component. Distinct biomaterials have been shown to differentially affect the maturation of dendritic cells (DCs). DCs are professional antigen-presenting cells (APCs) that bridge innate and adaptive immunity and play a central role in inducing immunity or initiating immune tolerance. However, the biomaterials systems used to study DC response thus far have been insufficient to draw a clear conclusion as to which biomaterial properties are the key to controlling DC phenotype. In this study, we developed a 96-well filter plate-based high-throughput (HTP) methodology to assess DC maturation upon biomaterial treatment. Equivalent biomaterial effects on DC phenotype were measured using the conventional flow cytometric and filter-plate method, which validated the HTP methodology. This methodology will be used to screen a large number of biomaterials simultaneously and to draw correlations between material properties and DC phenotype, thereby providing biomaterial design criteria and immunomodulatory strategies for both tissue engineering and vaccine delivery applications.