Browsing by Subject "Regeneration"
Now showing 1 - 10 of 39
Results Per Page
Sort Options
Item Advanced biomaterials for periodontal tissue regeneration(Wiley, 2022) Daghrery, Arwa; Bottino, Marco C.; Biomedical and Applied Sciences, School of DentistryThe periodontium is a suitable target for regenerative intervention, since it does not functionally restore itself after disease. Importantly, the limited regeneration capacity of the periodontium could be improved with the development of novel biomaterials and therapeutic strategies. Of note, the regenerative potential of the periodontium depends not only on its tissue‐specific architecture and function, but also on its ability to reconstruct distinct tissues and tissue interfaces, suggesting that the advancement of tissue engineering approaches can ultimately offer new perspectives to promote the organized reconstruction of soft and hard periodontal tissues. Here, we discuss material‐based, biologically active cues, and the application of innovative biofabrication technologies to regenerate the multiple tissues that comprise the periodontium.Item The antibacterial effect of new intracanal medicaments against established mutlispecies biofilm(2017) Troxel, Alex; Spolnik, Kenneth J.; Gregory, Richard; Ehrlich, Ygal; Bringas, Josef; Zunt, Susan L.; Yassen, GhaethWe investigated the antibacterial effect of low concentrations of double antibiotic paste (DAP) loaded into a methylcellulose system against bacterial biofilms obtained from mature and immature teeth with necrotic pulps. Standardized radicular dentin specimens were randomly divided into six experimental groups (n = 20). Group 1: 5mg/mL DAP treatment. Group 2: 1mg/mL DAP treatment. Group 3: Calcium hydroxide (Ca(OH)2) treatment. Group 4: Methylcellulose. Group 5: No treatment. Group 6: No bacteria or treatment. Clinical bacterial isolates were obtained from mature and immature teeth with necrotic pulps indicated for endodontic regeneration or routine endodontic treatment, respectively. Specimens in each group were inoculated with either bacterial isolates (n = 10) and incubated anaerobically for 3 weeks. Specimens were then treated for one week with the assigned group treatment. Treatments were rinsed with sterile saline and biofilms were detached and spiral plated using biofilm disruption assays. Wilcoxon Rank Sum tests followed by pair-wise comparisons were used for statistical analyses. Treatment of infected dentin with 1 mg/ml of DAP, 5 mg/mL of DAP, and Ca(OH)2 demonstrated significant and substantial antibiofilm effects in comparison to untreated control groups or groups treated with placebo paste. Furthermore, 1 mg/mL of DAP caused complete eradication of biofilm obtained from mature tooth with necrotic pulp. However, the same concentration was not able to completely eradicate biofilm obtained from the immature tooth with necrotic pulp. Low concentrations of DAP (1-5 mg/mL) loaded into a biocompatible methylcellulose system demonstrated significant antibacterial effects against biofilm obtained from both mature and immature teeth with necrotic pulps.Item Antimicrobial Effects of Novel Triple Antibiotic Paste-Mimic Scaffolds on Actinomyces naeslundii Biofilm(Elsevier, 2015-08) Albuquerque, Maria T.P.; Ryan, Stuart J.; Münchow, Eliseu A.; Kamocka, Maria M.; Gregory, Richard L.; Valera, Marcia C.; Bottino, Marco C.; Department of Medicine, IU School of MedicineINTRODUCTION: Actinomyces naeslundii has been recovered from traumatized permanent teeth diagnosed with necrotic pulps. In this work, a triple antibiotic paste (TAP)-mimic scaffold is proposed as a drug-delivery strategy to eliminate A. naeslundii dentin biofilm. METHODS: Metronidazole, ciprofloxacin, and minocycline were added to a polydioxanone (PDS) polymer solution and spun into fibrous scaffolds. Fiber morphology, mechanical properties, and drug release were investigated by using scanning electron microscopy, microtensile testing, and high-performance liquid chromatography, respectively. Human dentin specimens (4 × 4 × 1 mm(3), n = 4/group) were inoculated with A. naeslundii (ATCC 43146) for 7 days for biofilm formation. The infected dentin specimens were exposed to TAP-mimic scaffolds, TAP solution (positive control), and pure PDS (drug-free scaffold). Dentin infected (7-day biofilm) specimens were used for comparison (negative control). Confocal laser scanning microscopy was done to determine bacterial viability. RESULTS: Scaffolds displayed a submicron mean fiber diameter (PDS = 689 ± 312 nm and TAP-mimic = 718 ± 125 nm). Overall, TAP-mimic scaffolds showed significantly (P ≤ .040) lower mechanical properties than PDS. Within the first 24 hours, a burst release for all drugs was seen. A sustained maintenance of metronidazole and ciprofloxacin was observed over 4 weeks, but not for minocycline. Confocal laser scanning microscopy demonstrated complete elimination of all viable bacteria exposed to the TAP solution. Meanwhile, TAP-mimic scaffolds led to a significant (P < .05) reduction in the percentage of viable bacteria compared with the negative control and PDS. CONCLUSIONS: Our findings suggest that TAP-mimic scaffolds hold significant potential in the eradication/elimination of bacterial biofilm, a critical step in regenerative endodontics.Item The antimicrobial efficacy of innovative 3D triple antibiotic paste-mimic tubular scaffold against actinomyces naeslundii(2015) Azabi, Asma Abulqasem; Bottino, Marco C.; Gregory, Richard L.; Spolnik, Kenneth J.; Cook, Norman Blaine, 1954-; Chu, Tien-Min GabrielBackground: Root canal disinfection is an essential requirement for the success of regenerative endodontics. Currently, the so-called triple antibiotic paste (TAP) is considered the standard of care. Notwithstanding the good antimicrobial capacity, the high concentration of TAP has shown significant toxicity to human cells, especially dental pulp stem cells. A novel drug release system, i.e., a triple antibiotic paste-mimic electrospun scaffold containing low concentrations of the antibiotics present in the TAP, has emerged as an effective and reliable alternative to fight root canal infections without potential toxic effects on dental stem cells, which are an integral part of the regenerative treatment. Objectives: The aim of this study was to determine the antimicrobial efficacy of an innovative three-dimensional (3D) triple antibiotic paste-mimic tubular scaffold against Actinomyces naeslundii biofilm formed inside human root canal dentinal tubules. Materials and methods: Pure polydioxanone (PDS) polymer solution and PDS loaded with metronidazole, ciprofloxacin and minocycline (35 wt.% of each antibiotic, 3D-TAP-mimic scaffold) were spun into 3D fibrous scaffolds. A. naeslundii (ATCC 43146) was centrifuged to induce biofilm formation inside human root canal dentinal tubules using a dentin slice model (1 mm thickness and 2.5 mm canal diameter). The infected dentin slices were exposed to the 3D-TAP-mimic scaffold, TAP solution (50 mg/mL of each antibiotic), and antibiotic-free PDS. Biofilm elimination was quantitatively and qualitatively analyzed by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM), respectively. Results: A dense penetration of A. naeslundii biofilm was observed by CLSM throughout the dentinal tubules. 3D-TAP-mimic scaffold significantly reduced the percentage of viable bacteria compared with PDS (p <.05). TAP solution completely eliminated viable bacteria without differing from 3D-TAP-mimic scaffolds. SEM images showed results similar to CLSM. Conclusion: Collectively, the proposed tubular 3D-TAP-mimic scaffold holds significant clinical potential for root canal disinfection strategy prior to regenerative endodontics.Item Antimicrobial Efficacy of Triple Antibiotic-Eluting Polymer Nanofibers against Multispecies Biofilm(Elsevier, 2017-09) Albuquerque, Maria T.P.; Nagata, Juliana; Bottino, Marco C.; Biomedical Sciences and Comprehensive Care, School of DentistryThe elimination of microbial flora in cases of immature permanent teeth with necrotic pulp is both key and a challenging goal for the long-term success of regenerative therapy. Recent research has focused on the development of cell-friendly intracanal drug delivery systems. This in vitro study aimed to investigate the antimicrobial action of 3-dimensional (3D) tubular-shaped triple antibiotic-eluting nanofibrous constructs against a multispecies biofilm on human dentin. Polydioxanone polymer solutions, antibiotic-free or incorporated with metronidazole, ciprofloxacin, and minocycline, were electrospun into 3D tubular-shaped constructs. A multispecies biofilm consisting of Actinomyces naeslundii, Streptococcus sanguinis, and Enterococcus faecalis was forced inside the dentinal tubules via centrifugation in a dentin slice in vitro model. The infected specimens were exposed to 2 experimental groups (ie, 3D tubular-shaped triple antibiotic-eluting constructs and triple antibiotic paste [TAP]) and 2 control groups (7-day biofilm untreated and antibiotic-free 3D tubular-shaped constructs). Biofilm elimination was quantitatively analyzed with confocal laser scanning microscopy. Confocal laser scanning microscopic (CLSM) analysis showed a dense population of viable (green) bacteria adhered to dentin and penetrated into the dentinal tubules. Upon 3D tubular-shaped triple antibiotic-eluting nanofibrous construct exposure, nearly complete elimination of viable bacteria on the dentin surface and inside the dentinal tubules was shown in the CLSM images, which was similar (P < .05) to the bacterial death promoted by the TAP group but significantly greater when compared with both the antibiotic-free 3D tubular-shaped constructs and the control (saline). The proposed 3D tubular-shaped antibiotic-eluting construct showed pronounced antimicrobial effects against the multispecies biofilm tested and therefore holds significant clinical potential as a disinfection strategy before regenerative endodontics.Item The Axolotl Fibula as a Model for the Induction of Regeneration across Large Segment Defects in Long Bones of the Extremities(Public Library of Science, 2015) Chen, Xiaoping; Song, Fengyu; Jhamb, Deepali; Li, Jiliang; Bottino, Marco C.; Palakal, Mathew J.; Stocum, David L.; Department of Biology, School of ScienceWe tested the ability of the axolotl (Ambystoma mexicanum) fibula to regenerate across segment defects of different size in the absence of intervention or after implant of a unique 8-braid pig small intestine submucosa (SIS) scaffold, with or without incorporated growth factor combinations or tissue protein extract. Fractures and defects of 10% and 20% of the total limb length regenerated well without any intervention, but 40% and 50% defects failed to regenerate after either simple removal of bone or implanting SIS scaffold alone. By contrast, scaffold soaked in the growth factor combination BMP-4/HGF or in protein extract of intact limb tissue promoted partial or extensive induction of cartilage and bone across 50% segment defects in 30%-33% of cases. These results show that BMP-4/HGF and intact tissue protein extract can promote the events required to induce cartilage and bone formation across a segment defect larger than critical size and that the long bones of axolotl limbs are an inexpensive model to screen soluble factors and natural and synthetic scaffolds for their efficacy in stimulating this process.Item Axolotl Xenografts Improve Regeneration of Xenopus Hind Limbs(Office of the Vice Chancellor for Research, 2013-04-05) Chen, Xiaoping; Stocum, David L.Axolotls regenerate perfect copies of amputated limbs, whereas Xenopus froglet limbs regenerate only a spike of cartilage. We asked whether axolotl muscle and cartilage xenografted from normal or GFP-labeled limbs to amputated froglet limbs, with or without treatment with cyclosporin A (CSA) and/or retinoic acid (RA), would improve Xenopus limb regeneration via the release of regeneration-promoting factors into the host limb tissue. The grafted froglet limbs were allowed to regenerate for three months to two years. We detected initial symptoms of graft vs. host disease with or without CSA treatment that subsequently disappeared. The grafted limbs first formed a spike that subsequently grew wider at the tip and after three months began to separate into 2-5 digit-like structures that continued to grow. CSA and low-dose RA treatment decreased the time at which digit formation could be detected but were not necessary for digit formation. The digit pattern was not asymmetric, thus individual digits were not identifiable. Immature muscle was detected in the regenerated limbs by trichrome and MF-20 antibody staining, and nerve fibers were detected by Luxol Fast Blue staining. In one limb with a GFP graft, a few axolotl cells were detected around the base of the digits that may have stimulated digit separation. Although the mechanism of digit formation remains obscure, we conclude that factors released by degraded axolotl tissue or surviving axolotl cells can stimulate complex tissue regeneration and initiate the first step of digital anterior-posterior pattern formation in regenerating Xenopus hind limbs. These results have significance for the possibility of stimulating the regeneration of complex mammalian structures that have been injured by trauma or disease.Item Bioactive nanofibrous scaffolds for regenerative endodontics(SAGE, 2013-11) Bottino, M.C.; Kamocki, K.; Yassen, G.H.; Platt, J.A.; Vail, M.M.; Ehrlich, Y.; Spolnik, K.J.; Gregory, R.L.; Endodontics, School of DentistryHere we report the synthesis, materials characterization, antimicrobial capacity, and cytocompatibility of novel antibiotic-containing scaffolds. Metronidazole (MET) or Ciprofloxacin/(CIP) was mixed with a polydioxanone (PDS)polymer solution at 5 and 25 wt% and processed into fibers. PDS fibers served as a control. Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), tensile testing, and high-performance liquid chromatography (HPLC) were used to assess fiber morphology, chemical structure, mechanical properties, and drug release, respectively. Antimicrobial properties were evaluated against those of Porphyromonas gingivalis/Pg and Enterococcus faecalis/Ef. Cytotoxicity was assessed in human dental pulp stem cells (hDPSCs). Statistics were performed, and significance was set at the 5% level. SEM imaging revealed a submicron fiber diameter. FTIR confirmed antibiotic incorporation. The tensile values of hydrated 25 wt% CIP scaffold were significantly lower than those of all other groups. Analysis of HPLC data confirmed gradual, sustained drug release from the scaffolds over 48 hrs. CIP-containing scaffolds significantly (p < .00001) inhibited biofilm growth of both bacteria. Conversely, MET-containing scaffolds inhibited only Pg growth. Agar diffusion confirmed the antimicrobial properties against specific bacteria for the antibiotic-containing scaffolds. Only the 25 wt% CIP-containing scaffolds were cytotoxic. Collectively, this study suggests that polymer-based antibiotic-containing electrospun scaffolds could function as a biologically safe antimicrobial drug delivery system for regenerative endodontics.Item Bioactivity of Dental Restorative Materials: FDI Policy Statement(Elsevier, 2023) Schmalz, Gottfried; Hickel, Reinhard; Price, Richard Bengt; Platt, Jeffrey A.; Biomedical Sciences and Comprehensive Care, School of DentistryThe term bioactivity is being increasingly used in medicine and dentistry. Due to its positive connotation, it is frequently utilised for advertising dental restorative materials. However, there is confusion about what the term means, and concerns have been raised about its potential overuse. Therefore, FDI decided to publish a Policy Statement about the bioactivity of dental restorative materials to clarify the term and provide some caveats for its use in advertising. Background information for this Policy Statement was taken from the current literature, mainly from the PubMed database and the internet. Bioactive restorative materials should have beneficial/desired effects. These effects should be local, intended, and nontoxic and should not interfere with a material's principal purpose, namely dental tissue replacement. Three mechanisms for the bioactivity of such materials have been identified: purely biological, mixed biological/chemical, or strictly chemical. Therefore, when the term bioactivity is used in an advertisement or in a description of a dental restorative material, scientific evidence (in vitro or in situ, and preferably in clinical studies) should be provided describing the mechanism of action, the duration of the effect (especially for materials releasing antibacterial substances), and the lack of significant adverse biological side effects (including the development and spread of antimicrobial resistance). Finally, it should be documented that the prime purpose, for instance, to be used to rebuild the form and function of lost tooth substance or lost teeth, is not impaired, as demonstrated by data from in vitro and clinical studies. The use of the term bioactive dental restorative material in material advertisement/information should be restricted to materials that fulfil all the requirements as described in the FDI Policy Statement.Item Cardiac Troponin I-interacting Kinase impacts cardiomyocyte S-phase activity but not cardiomyocyte proliferation(American Heart Association, 2023) Reuter, Sean P.; Soonpaa, Mark H.; Field, Dorothy; Simpson, Ed; Rubart-von der Lohe, Michael; Lee, Han Kyu; Sridhar, Arthi; Ware, Stephanie M.; Green, Nick; Li, Xiaochun; Ofner, Susan; Marchuk, Douglas A.; Wollert, Kai C.; Field, Loren J.; Pediatrics, School of MedicineBackground: Identifying genetic variants that affect the level of cell cycle reentry and establishing the degree of cell cycle progression in those variants could help guide development of therapeutic interventions aimed at effecting cardiac regeneration. We observed that C57Bl6/NCR (B6N) mice have a marked increase in cardiomyocyte S-phase activity after permanent coronary artery ligation compared with infarcted DBA/2J (D2J) mice. Methods: Cardiomyocyte cell cycle activity after infarction was monitored in D2J, (D2J×B6N)-F1, and (D2J×B6N)-F1×D2J backcross mice by means of bromodeoxyuridine or 5-ethynyl-2'-deoxyuridine incorporation using a nuclear-localized transgenic reporter to identify cardiomyocyte nuclei. Genome-wide quantitative trait locus analysis, fine scale genetic mapping, whole exome sequencing, and RNA sequencing analyses of the backcross mice were performed to identify the gene responsible for the elevated cardiomyocyte S-phase phenotype. Results: (D2J×B6N)-F1 mice exhibited a 14-fold increase in cardiomyocyte S-phase activity in ventricular regions remote from infarct scar compared with D2J mice (0.798±0.09% versus 0.056±0.004%; P<0.001). Quantitative trait locus analysis of (D2J×B6N)-F1×D2J backcross mice revealed that the gene responsible for differential S-phase activity was located on the distal arm of chromosome 3 (logarithm of the odds score=6.38; P<0.001). Additional genetic and molecular analyses identified 3 potential candidates. Of these, Tnni3k (troponin I-interacting kinase) is expressed in B6N hearts but not in D2J hearts. Transgenic expression of TNNI3K in a D2J genetic background results in elevated cardiomyocyte S-phase activity after injury. Cardiomyocyte S-phase activity in both Tnni3k-expressing and Tnni3k-nonexpressing mice results in the formation of polyploid nuclei. Conclusions: These data indicate that Tnni3k expression increases the level of cardiomyocyte S-phase activity after injury.