Transcriptome analysis of human peri-implant soft tissue and periodontal gingiva: a paired design study.

OBJECTIVES: Limited information is available about the biological characterization of peri-implant soft tissue at the transcriptional level. The aim of this study was to investigate the effect of dental implant on the soft tissue in vivo by using paired samples and compare the differences between peri-implant soft tissue and periodontal gingiva at the transcriptional level. METHODS: Paired peri-implant soft tissue and periodontal gingiva tissue from 6 patients were obtained, and the pooled RNAs were analyzed by deep sequencing. Venn diagram was used to further screen out differentially expressed genes in every pair of samples. Annotation and enrichment analysis was performed. Further verification was done by quantitative real-time PCR. RESULTS: Totally 3549 differentially expressed genes (DEGs) were found between peri-implant and periodontal groups. The Venn diagram further identified 185 DEGs in every pair of samples, of which the enrichment analysis identified significant enrichment for cellular component was associated with external side of plasma membrane, for molecular function was protein binding, for biological process was immune system process, and for KEGG pathway was cytokine-cytokine receptor interaction. Among the DEGs, CST1, SPP1, AQP9, and SFRP2 were verified to be upregulated in peri-implant soft tissue. CONCLUSIONS: Peri-implant soft tissue showed altered expressions of several genes related to the cell-ECM interaction compared to periodontal gingiva. CLINICAL RELEVANCE: Compared to periodontal gingiva, altered cell-ECM interactions in peri-implant may contribute to the susceptibility of peri-implant diseases. At the transcriptional level, periodontal gingiva is generally considered the appropriate control for peri-implantitis, except regarding the cell-ECM interactions.

Memory B Cell as an Indicator of Peri-implantitis Status: A Pilot Study.

PURPOSE: Gingiva-resident memory B cells found recently in healthy periodontal tissue may play important roles in maintaining homeostasis against bacterial plaque. Whether resident memory B cells exist in healthy peri-implant tissue and how they respond in peri-implantitis lesions are of interest. The aim of this study was to preliminarily investigate whether memory B cell activities are related to inflamed or healthy peri-implant status. MATERIALS AND METHODS: Patients with peri-implantitis or healed implants were recruited. The gingiva samples were collected and divided into inflamed (n = 4), treated (n = 4), and healed (n = 3) groups, followed by a flow cytometry analysis staining with CD3, CD19, CD27, CD38, and RANKL. The biopsy samples were also cryo-embedded for immunofluorescent double staining of CD19 and CD27. RESULTS: CD27+ CD38+ ASC comprised 83.3% ± 3.3% of the total B cells in the inflamed group, and this proportion in the treated group was reduced to 44.5% ± 13.4%. The proportion of CD27+ CD3+ T cells was found to be unchanged between the inflamed and treated groups. Immunofluorescent staining indicated that CD19+ CD27+ population infiltrated peri-implant connective tissue. RANKL was expressed by almost all B cells and a portion of T cells in the inflamed group, while the proportions of RANKL+ B and T cells were significantly reduced in the treated group. Barely any memory B cells were detected in the healed group. CONCLUSION: Memory B cells were markedly activated in peri-implantitis and responded to the suprastructure removal treatment. The lack of gingiva-resident memory B cells in the clinically healed implants serves as a hint for the weakness of peri-implant tissue against bacterial plaque.

Tuning the immune reaction to manipulate the cell-mediated degradation of a collagen barrier membrane.

In order to elicit a desired barrier function in guided bone regeneration (GBR) or guided tissue regeneration (GTR), a barrier membrane has to maintain its integrity for a certain period of time to guarantee the regeneration of target tissue. Due to the complexity and variety of clinical conditions, the healing time required for tissue regeneration varies from one case to another, which implies the need for tailoring the barrier membranes to diverse conditions via manipulating their degradation property. As a "non-self" biomaterial, a barrier membrane will inevitably trigger host-membrane immune response after implantation, which entails the activation of phagocytic cells. In the degradation process of a barrier membrane, the cell-mediated degradation may play a more vital role than enzymatic and physicochemical dissolution; however, limited studies have been carried out on this topic. In this context, we investigated the cell-mediated degradation and illustrated the possible key cells and mediators for immunomodulation via in vivo and in vitro studies. We discovered that IL-13, a key cytokine mainly released by T helper 2 cells (Th2), induced the formation of foreign body giant cells (FBGCs), thus resulting in membrane degradation. Neutralizing IL-13 could suppress membrane degradation and formation of FBGC. The contributions of this study are (1) unveiling the immune mechanisms underlying the cell-mediated collagen membrane degradation; (2) allowing the formation of an "immunodegradation" strategy to develop an "immune-smart" barrier membrane to manipulate its degradation; (3) providing the key regulatory immune cells and cytokines for the immunomodulation target in collagen membrane degradation. STATEMENT OF SIGNIFICANCE: The significance of this research includes.

3D-Printed Artificial Teeth: Accuracy and Application in Root Canal Therapy.

This study examined the compatibility of 3D-printed artificial teeth and extracted teeth by combining oral cone-beam computed tomography (CBCT) and multi-jet printing technology to print the extracted teeth in vitro. The 3D-printed artificial teeth were then used to choose a master gutta-percha with an appropriate working length and taper to fill root canals. The quality of root canal-filling was evaluated via X-ray. Twenty orthodontically extracted premolars with a single root canal were collected and CBCT-scanned, and the scan data were extracted and converted to 3D models using MIMICS software, which in turn were used to 3D-print artificial teeth using multi-jet printing technology. The artificial teeth were re-scanned by CBCT to acquire 3D scan data, and the 3D deviation between the 3D-printed artificial teeth and extracted teeth was analyzed using Geomagic Studio software, in which the root canal cross-sections at 3 mm, 6 mm and 9 mm from the apex were measured and statistically analyzed. Clinically, three cases of adult anterior teeth with root canals were treated, and artificial teeth for root canal preparation were 3D-printed using multi-jet printing technology. A master gutta-percha with an appropriate working length and taper was matched and chosen to fill the root canal based on the root canal of the 3D-printed artificial tooth, and the quality of filling was evaluated by X-ray. An analysis of the 3D deviation between the 3D-printed artificial teeth prepared by combining oral CBCT and multi-jet printing technology and the original extracted teeth showed that the teeth were well-matched. There were no significant differences between the teeth regarding root canal cross-sections at 3 mm, 6 mm and 9 mm from the apex (P > 0.05). In the three clinical cases, postoperative X-ray examination showed that the root canal filling with the master gutta-percha prepared by in vitro matching based on the 3D-printed artificial teeth was good quality. The combination of CBCT and multi-jet printing technology generated accurate 3D-printed artificial teeth, which provided a master gutta-percha with a matching working length and taper for the in vivo root canal, thus providing a new approach to improve the rate of correct fill-ins in root canal fillings.

A micro-computed tomographic evaluation of dentinal microcrack alterations during root canal preparation using single-file Ni-Ti systems.

The aim of the present study was to evaluate the length of dentinal microcracks observed prior to and following root canal preparation with different single-file nickel-titanium (Ni-Ti) systems using micro-computed tomography (micro-CT) analysis. A total of 80 mesial roots of mandibular first molars presenting with type II Vertucci canal configurations were scanned at an isotropic resolution of 7.4 µm. The samples were randomly assigned into four groups (n=20 per group) according to the system used for root canal preparation, including the WaveOne (WO), OneShape (OS), Reciproc (RE) and control groups. A second micro-CT scan was conducted after the root canals were prepared with size 25 instruments. Pre- and postoperative cross-section images of the roots (n=237,760) were then screened to identify the lengths of the microcracks. The results indicated that the microcrack lengths were notably increased following root canal preparation (P<0.05). The alterations in microcrack length in the OS group were more significant compared with those in the WO, RE and control groups (P<0.05). In conclusion, the formation and development of dentinal microcracks may be associated with the movement caused by preparation rather than the taper of the files. Among the single-file Ni-Ti systems, WO and RE were not observed to cause notable microcracks, while the OS system resulted in evident microcracks.

Comparison of Hero 642 and K3 rotary nickel-titanium files in curved canals of molars and a systematic review of the literature.

The aim of the present study was to compare the root canal preparation ability of rotary nickel-titanium (NiTi) Hero 642 and K3 files in curved mandibular or maxillary molars. A total of 40 extracted mandibular molars with two separate mesial canals, an apical width of approximately size ≤15 and a root canal curvature of 15-30° were randomly divided into two groups and instrumented using Hero 642 (n=20) or K3 files (n=20). Canal straightening, working length, transportation, cross-sectional area, minimum dentin thickness and the canal angle curvature degree were examined, and a systematic review of the literature was conducted. No statistically significant differences were observed between the two groups with regard to the mean degree of straightening, mean change in working length, mean transportation, amount of dentin removed or remaining minimum dentin thickness (P>0.05). The canal angle curvature decreased in the two groups postoperatively. The systematic review identified six studies, and overall the two files performed similarly in the majority of categories examined. Therefore, the rotary NiTi Hero 642 and K3 files demonstrated comparable shaping abilities and maintenance of working length.