Multi-omics analysis of oral bacterial biofilm on titanium oxide nanostructure modified implant surface: In vivo sequencing-based pilot study in beagle dogs.

Peri-implantitis, the major cause of implant failure, is an inflammatory destructive disease due to the dysbiotic polymicrobial communities at the peri-implant sites. Therefore, it is highly warranted to develop the implant materials with antimicrobial properties and investigate their effects on oral microbiota. However, most of the relevant studies were performed in vitro, and insufficient to provide the comprehensive assessment of the antimicrobial capacity of the implant materials in vivo. Herein, we introduce an innovative approach to evaluate the in vivo antibacterial properties of the most commonly used implant materials, titanium with different nanostructured surfaces, and investigate their antibacterial mechanism via the next-generation sequencing (NGS) technology. We firstly prepared the titanium implants with three different surfaces, i) mechanical polishing (MP), ii) TiO2 nanotubes (NT) and iii) nanophase calcium phosphate embedded to TiO2 nanotubes (NTN), and then characterized them using scanning electron microscopy (SEM), energy-dispersive X-ray spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), confocal laser scanning microscopy (CLSM) and surface hydrophilicity analysis. Afterwards, the implants were placed in the beagle dogs' mouths to replace the pre-extracted premolar and molar teeth for eight weeks through implant surgery. The supra- and sub-mucosal plaques were collected and subjected to 16S rRNA gene/RNA sequencing and data analysis. It was found that the nanostructured surfaces in NT and NTN groups showed significantly increased roughness and decreased water contact angles compared to the MP group, while the XPS data further confirmed the successful modifications of TiO2 nanotubes and the subsequent deposition of nanophase calcium phosphate. Notably, the nanostructured surfaces in NT and NTN groups had limited impact on the diversity and community structure of oral microbiota according to the 16S rRNA sequencing results, and the nanostructures in NTN group could down-regulate the genes associated with localization and locomotion based on Gene Ontology (GO) terms enrichment analysis. Moreover, the differentially expressed genes (DEGs) were associated with microbial metabolism, protein synthesis and bacterial invasion of epithelial cells. Taken together, this study provides a new strategy to evaluate the antibacterial properties of the biomedical materials in vivo via the high-throughput sequencing and bioinformatic approaches, revealing the differences of the composition and functional gene expressions in the supra- and sub-mucosal microbiome.

Micro-/nano-topography of selective laser melting titanium enhances adhesion and proliferation and regulates adhesion-related gene expressions of human gingival fibroblasts and human gingival epithelial cells.

BACKGROUND: Selective laser melting (SLM) titanium is an ideal option to manufacture customized implants with suitable surface modification to improve its bioactivity. The peri-implant soft tissues form a protective tissue barrier for the underlying osseointegration. Therefore, original microrough SLM surfaces should be treated for favorable attachment of surrounding soft tissues. MATERIAL AND METHODS: In this study, anodic oxidation (AO) was applied on the microrough SLM titanium substrate to form TiO2 nanotube arrays. After that, calcium phosphate (CaP) nanoparticles were embedded into the nanotubes or the interval of nanotubes by electrochemical deposition (AOC). These two samples were compared to untreated (SLM) samples and accepted mechanically polished (MP) SLM titanium samples. Scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction, surface roughness, and water contact angle measurements were used for surface characterization. The primary human gingival epithelial cells (HGECs) and human gingival fibroblasts (HGFs) were cultured for cell assays to determine adhesion, proliferation, and adhesion-related gene expressions. RESULTS: For HGECs, AOC samples showed significantly higher adhesion, proliferation, and adhesion-related gene expressions than AO and SLM samples (P<0.05) and similar exceptional ability in above aspects to MP samples. At the same time, AOC samples showed the highest adhesion, proliferation, and adhesion-related gene expressions for HGFs (P<0.05). CONCLUSION: By comparison between each sample, we could confirm that both anodic oxidation and CaP nanoparticles had improved bioactivity, and their combined utilization may likely be superior to mechanical polishing, which is most commonly used and widely accepted. Our results indicated that creating appropriate micro-/nano-topographies can be an effective method to affect cell behavior and increase the stability of the peri-implant mucosal barrier on SLM titanium surfaces, which contributes to its application in dental and other biomedical implants.

Enhanced antibacterial efficacy of selective laser melting titanium surface with nanophase calcium phosphate embedded to TiO2 nanotubes.

Selective laser melting (SLM) has promising prospects in manufacturing customized implants, however the rough surface of SLM titanium specimen can facilitate bacterial adherence and biofilm formation, which is a risk to implant success. Therefore, surface modification is required to enhance its antibacterial efficacy. Sandblasting, anodization and electrochemical deposition were applied to construct a novel composite nanostructure of nanophase calcium phosphate embedded to TiO2 nanotubes on microrough SLM titanium substrates (NTN). NTN samples were compared with TiO2 nanotubes (NT) samples, mechanical polished (MP) samples and untreated SLM titanium samples. Surface characterization were analyzed using scanning electron microscope, energy dispersive spectroscopy, x-ray photoelectron spectroscopy, x-ray diffraction, a three dimensional profilometer and a contact angle measuring device. Bacteria adhesion assay for bacteria colony counting and bacteria LIVE/DEAD staining was conducted using Streptococcus mutans and Streptococcus sanguinis. Both S. mutans and S. sanguinis adherence on SLM samples were significantly higher than on NTN, NT and MP samples. The antibacterial efficacy of NTN samples was superior compared to NT and had no significant difference with MP samples, despite the fact that NTN samples had much rougher surface than MP samples. This study elucidates an efficient method to enhance antibacterial efficacy on rough SLM surfaces, which contributes to its application in dental and other biomedical implants.

Clinical Outcomes of Bicortical Engagement Implants in Atrophic Posterior Maxillae: A Retrospective Study with 1 to 5 Years Follow-up.

Bicortical dental implantation technique was regarded as an alternative to internal sinus lift technique with bone grafting in dental implantation in atrophic maxillae. The purpose of this retrospective study was to evaluate the survival rates and bone stability of 6- and 10-mm implants in the posterior maxilla using bicortical dental implantation techniques after 1 to 5 years of prosthetic loading. A total of 53 patients received posterior maxillary implant treatments. Of these, 31 patients received bicortical dental implantation (group A), and 25 patients received traditional implantation (group B). Three patients received an implant with bicortical engagement and another implant without bicortical engagement. The survival rates were calculated, and the marginal bone heights were measured on radiographs at baseline and follow-up. The survival rate of group A was 100%. In contrast, the survival rate of group B was only 74.68%, with survival rates of 51.85% in the 6-mm implant subgroup and 93.33% in the 10-mm implant subgroup. In terms of variations in implant marginal bone heights, a significant difference was found only between the 6-mm subgroups in groups A and B. Significant intrasinus bone gain was found on the mesial and distal sides of the implants in group A. Application of bicortical dental implantation techniques with 6-mm implants could achieve better clinical outcomes in atrophic posterior maxillae.

Influence of Lateral-Medial Sinus Width on No-Grafting Inlay Osteotome Sinus Augmentation Outcomes.

PURPOSE: Intrasinus new bone formation (BF) has been observed after no-grafting osteotome sinus augmentation, and it is hypothesized to be influenced by the dimensions of the maxillary sinus. The aim of this clinical trial is to evaluate the influence of lateral-medial sinus width (SW) on no-grafting osteotome sinus augmentation outcomes using cone-beam computed tomography. PATIENTS AND METHODS: All patients recruited for this prospective study were treated with no-grafting osteotome sinus augmentation with simultaneous implant placement. Cone-beam computed tomography was obtained before, immediately after, and 6 months after the surgical procedure to use for measurements. Descriptive statistics were calculated and univariate, bivariate, and multivariate analysis were conducted to evaluate the influence of average SW and other relevant factors on procedure outcomes, including new BF, residual bone resorption (BR), and change of peri-implant bone height (CPBH). RESULTS: A total of 48 implants placed in 32 elevated sinuses of 29 patients were included. The average SW was 11.3 ± 1.8 mm. Intrasinus BF measured 1.7 ± 0.9 mm at 6 months after surgery. The amount of BR was 0.3 ± 0.9 mm, and CPBH was calculated as 1.3 ± 1.3 mm. Multivariate analysis showed a negative correlation between SW and BF (r = -0.469, P = .001), as well as between SW and CPBH (r = -0.562, P = .001). A positive correlation was discovered between SW and BR (r = 0.311, P = .027) in general. CONCLUSIONS: The lateral-medial SW was observed to have a negative correlation with new BF and CPBH after no-grafting osteotome sinus augmentation.

Improved performance of collagen scaffolds crosslinked by Traut's reagent and Sulfo-SMCC.

Collagen scaffolds are frequently employed for applications in regenerative medicine. In previous studies, we affirmed that Traut's reagent (2-Iminothiolane hydrochloride) and Sulfo-SMCC (4-(N-Maleimidomethyl) cyclohexane-1-carboxylic acid 3-sulpho-N-hydroxysuccinimide ester sodium salt) could covalently bind growth factors on collagen scaffolds. We also observed that crosslinking formed within the collagen scaffolds with excess dosage of Sulfo-SMCC, which improved the biological performance of collagen scaffolds together with growth factors. In order to evaluate changes in capacity caused by crosslinking, Traut's reagent and adjusted different concentrations of Sulfo-SMCC (0.263, 1.315, 2.63 and 5.26 mM) were used to construct collagen scaffolds with differing extents of crosslinking in this study. The results demonstrated that resistance of collagen scaffolds to enzymatic digestion, cellularization and vascularization in vivo were enhanced by the crosslinking procedure. The cell culture studies indicated that the crosslinking procedure did not influence biocompatibility. Moreover, there were no statistical differences in the degradation rate, cellularization or vascularization among 1.315, 2.63 and 5.26 mM crosslinked groups. These results demonstrated that crosslinking collagen scaffolds with an appropriate amount of Traut's reagent and Sulfo-SMCC was an effective and safe method to modify naturally derived collagen scaffolds with notable potential uses in tissue regeneration.

Clinical application and research progress of All-on-Four / 口腔疾病防治

@#To seek convenient and effective method for reconstruction of edentulous jaw, Maló and his colleagues developed All-on-Four implant immediate-function concept. The principle of All-on-Four is to support the full-arch prosthesis by 4 implants and to achieve immediate loading after surgery. Its advantages include avoiding additional bone grafting, evading critical anatomical structures and immediate prosthesis. In recent years, All-on-Four technique has been widely utilized in clinical practice as a viable approach for edentulous patients. With the auxiliary of guided surgery and biomechanical researches, All-on-Four has achieved predictable clinical results. In this paper, the development, investigation of biomechanics and main points of surgery and prosthesis of All-on-Four were briefly reviewed.