Age-related changes of dental pulp tissue after experimental tooth movement in rats.
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ABSTRACT:
SUBMITTER: Von Bohl M
PROVIDER: S-EPMC4741077 | biostudies-literature | 2016
REPOSITORIES: biostudies-literature
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Project description:BackgroundOrthodontic treatment may result in undesirable side effects, such as root resorption and a decrease in the size of the pulp tissue which could be associated with the duration of the orthodontic treatment. Piezocision-assisted tooth movement was introduced as a minimally invasive surgical procedure to shorten orthodontic treatment time. This prospective randomized clinical trial was aimed to compare the pulp volume changes of maxillary anterior teeth after en-masse retraction with or without piezocision-assisted orthodontics.MethodsPatients who required orthodontic treatment with bilateral maxillary first premolar extractions and en-masse retraction were recruited. Patients were randomly divided into extraction with piezocision, or only extraction, serving as controls. Pulp volume and root length changes of the maxillary six anterior teeth were measured and compared between the two groups using a 3-Dimensional analytical software. Paired and independent sample t-tests were used to compare within and between groups. Bivariate correlation was done between the mean change in pulp volume and its corresponding root length. The significance level was set at α = 0.05.ResultsA total of 23 patients were included, 12 in the piezocision, and 11 in the control group. At the end of the en-masse retraction phase, (mean = 122.74 ± 3.06 days) pulp volume was significantly decreased in all six anterior teeth in both groups (P < 0.01). The decrease in pulp volume was not statistically different between both groups, (P > 0.05). There was a statistically significant but moderate correlation only between the pulp volume change of the right canine and its root length, r = 0.44, P = 0.034.ConclusionsThe effect of piezocision-assisted orthodontic tooth movement on the pulp volume was comparable to the conventional orthodontic treatment. The degree of change in pulp volume does not appear to be related to the amount of root resorption. Trial registration NCT03180151. Registered December 25, 2016, retrospectively registered, https://clinicaltrials.gov/ct2/show/record/NCT03180151 .
| S-EPMC7805050 | biostudies-literature
Project description:Dental pulp is involved in the formation of bone-like tissue in response to external stimuli. However, the origin of osteoblast-like cells constructing this tissue and the mechanism of their induction remain unknown. We therefore evaluated pulp mineralization induced by transplantation of a green fluorescent protein (GFP)-labeled tooth into a GFP-negative hypodermis of host rats. Five days after the transplantation, the upper pulp cavity became necrotic; however, cell-rich hard tissue was observed adjacent to dentin at the root apex. At 10 days, woven bone-like tissue was formed apart from the dentin in the upper pulp. After 20 days, these hard tissues expanded and became histologically similar to bone. GFP immunoreactivity was detected in the hard tissue-forming cells within the root apex as well as in the upper pulp. Furthermore, immunohistochemical observation of α-smooth muscle actin, a marker for undifferentiated cells, showed a positive reaction in cells surrounding this bone-like tissue within the upper pulp but not in those within the root apex. Immunoreactivities of Smad4, Runx2, and Osterix were detected in the hard tissue-forming cells within both areas. These results collectively suggest that the dental pulp contains various types of osteoblast progenitors and that these cells might thus induce bone-like tissue in severely injured pulp.
| S-EPMC3524570 | biostudies-literature
Project description:Age is an important parameter to better understand wildlife populations, and is especially relevant for interpreting data for fecundity, health, and survival assessments. Estimating ages for marine mammals presents a particular challenge due to the environment they inhabit: accessibility is limited and, when temporarily restrained for assessment, the window of opportunity for data collection is relatively short. For wild dolphins, researchers have described a variety of age-determination techniques, but the gold-standard relies upon photo-identification to establish individual observational life histories from birth. However, there are few populations with such long-term data sets, therefore alternative techniques for age estimation are required for individual animals without a known birth period. While there are a variety of methods to estimate ages, each involves some combination of drawbacks, including a lack of precision across all ages, weeks-to-months of analysis time, logistical concerns for field applications, and/or novel techniques still in early development and validation. Here, we describe a non-invasive field technique to determine the age of small cetaceans using periapical dental radiography and subsequent measurement of pulp:tooth area ratios. The technique has been successfully applied for bottlenose dolphins briefly restrained during capture-release heath assessments in various locations in the Gulf of Mexico. Based on our comparisons of dental radiography data to life history ages, the pulp:tooth area ratio method can reliably provide same-day estimates for ages of dolphins up to about 10 years old.
| S-EPMC7678971 | biostudies-literature
Project description:The novel aspect of this study was to contextualize the co-localization of biomolecular expression in widened and narrowed periodontal ligament (PDL)-space within a mechanically activated periodontal complex. The PDL is unique as it is the only ligament with both innervation and vascularization. Maxillary molars in 6-week-old male C57BL/6 mice (N = 5) were experimentally translated for 2 weeks using an elastic spacer. Contralateral teeth were used as controls. Mechanical testing of the periodontal complex of a mouse in situ and imaging using X-ray micro-computed tomography (micro-XCT) illustrated deformations within blood vessels (BV) of the PDL. PDL-bone and PDL-cementum entheses at the widened and narrowed PDL-spaces following experimental tooth movement (ETM) illustrated osterix (OSX), bone sialoprotein (BSP), cluster of differentiation 146 (CD146), and protein gene product 9.5 (PGP9.5), indicating active remodeling at these sites. PGP9.5 positive nerve bundles (NBs) were co-localized with multinucleated cells (MCs), Howship's resorption lacunae, and CD146 positive BVs. Association between nerves and MC was complemented by visualizing the proximity of osmium tetroxide stained NBs with the ultrastructure of MCs by performing scanning transmission electron microscopy. Spatial association of NB with BV, and NB with MC, provided insights into the plausible co-activation of NBs to initiate osteoclastic activity. Resorption of mineral occurred as an attempt to restore PDL-space of the load-bearing complex, specifically at the PDL-entheses. Mapping of anatomy-specific structural elements and their association with regenerative molecules by correlating light and electron micrographs provided insights into the use of these extracellular matrix molecules as plausible targets for pharmacological interventions related to tooth movement. Within the realm of tissue regeneration, modulation of load can reverse naturally occurring mineral formation to experimentally induced resorption, and naturally occurring mineral resorption to experimentally induced formation at the enthesial sites to permit tooth translation.
| S-EPMC6465084 | biostudies-literature
Project description:Dental pulp-derived stem cells (DPSCs) have the potential to regenerate dentin and dental pulp tissue because of their differentiation capacity and angiogenic properties. However, for regenerative approaches to gain regulatory and clinical acceptance, protocols are needed to determine more feasible ways to cultivate DPSCs, namely, without the use of xenogeneic-derived components (animal sera) and exogenous growth factors.In this study, human DPSCs were isolated from third molars and expanded in standard culture conditions containing fetal bovine serum (DPSCs-FBS) or conditions containing human serum (DPSCs-HS). After cell characterization and evaluation of their angiogenic secretome, DPSCs were seeded in tooth slice/scaffolds and implanted subcutaneously into immunodeficient mice. After 30 days, tooth slices were retrieved and evaluated for dental pulp tissue regeneration. Immunohistochemistry and confocal microscopy were used to quantify blood vessel formation and evaluate predentin and dentin formation.After culture, DPSCs-HS produced concentrations of angiogenic growth factors equivalent to DPSCs-FBS. Additionally, in DPSCs-HS, several angiogenic factors were produced in at least 1-fold higher concentrations than in DPSCs-FBS. In vivo, it was determined that DPSCs-HS produced a robust angiogenic response and regeneration of dentin equivalent to DPSCs-FBS.These findings show that DPSCs can be isolated and expanded to clinical scale numbers in media devoid of animal serum or exogenous growth factors and still maintain their pulp regenerative properties. The implications of these findings are significant for further development of clinical protocols using DPSCs in cell therapies.
| S-EPMC5797986 | biostudies-literature
Project description:Dental pulp stem/stromal cells (DPSCs) are categorized as adult stem cells (ASCs) that retain multipotent differentiation capabilities. DPSCs can be isolated from individuals at any age and are considered to be true personal stem cells, making DPSCs one of the potential options for stem cell therapy. However, the properties of DPSCs from individuals with an inherited genetic disorder, such as Huntington's disease (HD), have not been fully investigated.To examine if mutant huntingtin (htt) protein impacts DPSC properties, we have established DPSCs from tooth germ of transgenic monkeys that expressed both mutant htt and green fluorescent protein (GFP) genes (rHD/G-DPSCs), and from a monkey that expressed only the GFP gene (rG-DPSCs), which served as a control. Although mutant htt and oligomeric htt aggregates were overtly present in rHD/G-DPSCs, all rHD/G-DPSCs and rG-DPSCs shared similar characteristics, including self-renewal, multipotent differentiation capabilities, expression of stemness and differentiation markers, and cell surface antigen profile.Our results suggest that DPSCs from Huntington monkeys retain ASC properties. Thus DPSCs derived from individuals with genetic disorders such as HD could be a potential source of personal stem cells for therapeutic purposes.
| S-EPMC3189880 | biostudies-other
Project description:The NLRP3/caspase-1 inflammasome pathway plays an important role in cellular immune defence against bacterial infection; however, its function in human dental pulp tissue and human dental pulp fibroblasts remains poorly understood. We demonstrate that NLRP3 protein expression occurs to a greater extent in pulp tissue with irreversible pulpitis than in normal pulp tissue and in tissue with reversible pulpitis. Caspase-1 is present in its active (cleaved) form only in pulp tissue with irreversible pulpitis. NLRP3 and caspase-1 are expressed in the odontoblast layers in normal human dental pulp tissue, whereas in inflamed pulp tissue, the odontoblast layers are disrupted and dental pulp cells are positive for NLRP3 and caspase-1. Additionally, we investigate the role of the NLRP3/caspase-1 inflammasome pathway in human dental pulp fibroblasts and show that ATP activates the P2X7 receptor on the cell membrane triggering K(+) efflux and inducing the gradual recruitment of the membrane pore pannexin-1. Extracellular lipopolysaccharide is able to penetrate the cytosol and activate NLRP3. Furthermore, the low intracellular K(+) concentration in the cytosol triggers reactive oxygen species generation, which also induces the NLRP3 inflammasome. Thus, the NLRP3/caspase-1 pathway has a biological role in the innate immune response mounted by human dental pulp fibroblasts.
| S-EPMC4529451 | biostudies-literature
Project description:BACKGROUND:Accelerated tooth movement has been a topic of interest for orthodontic research recently. Surgically facilitated orthodontic treatment has been shown to be an effective approach to accelerate tooth movement; however, it remains invasive, requires additional surgery, and may increase post-operative complications. In this study, we evaluate the effects of extracorporeal shockwave treatment (ESWT), a non-invasive approach to regenerate alveolar bone, on orthodontic tooth movement in rats. MATERIALS AND METHODS:Seventy-two male rats, aged 10 weeks old, were subjected to 10-cN closed-coil nickel-titanium springs for unilateral maxillary first molar tooth movement. One group of rats received a single treatment of extracorporeal shockwave treatment at 500 impulses at energy flux density 0.1 mJ/mm2, with a pulse rate of 5 pulses per second immediately after spring installation while the non-ESWT-treated group served as a control group. The rats were sacrificed at day 3, 7, 14, 21 and 28 for tooth movement evaluation and sample analyses. Faxitron radiography, histological, double bone labeling and gene expression analyses were performed. Serum biochemistry was evaluated at day 3, 7 and 28 of the study. Kruskal-Wallis analysis of variance was used to determine the mean difference among groups, and multiple comparisons were analyzed by Mann-Whitney-U tests with a significance level?=?0.05. RESULTS:The results demonstrated that tooth movement in the ESWT-treated rats (0.11 ± 0.07 mm) was impeded compared to the tooth movement in the non-ESWT-treated rats (0.44 ± 0.09 mm). ESWT up-regulated several osteoblastic and osteoclastic gene markers and cytokines; however, the effects on osteoclasts were only transient. Double-fluorescence bone labeling demonstrated that osteoblastic activity increased after ESWT treatment. There was no difference in systemic RANKL/OPG ratio between groups. CONCLUSIONS:ESWT at 500 impulse at energy flux density 0.1 mJ/mm2 increased osteoblast and osteoclast activities and imbalanced bone remodeling resulting in impeded tooth movement in rats.
| S-EPMC6233511 | biostudies-literature
Project description:The aim of this study was to extensively characterise natal dental pulp stem cells (nDPSC) and assess their efficiency to generate human induced pluripotent stem cells (hiPSC). A number of distinguishing features prompted us to choose nDPSC over normal adult DPSC, in that they differed in cell surface marker expression and initial doubling time. In addition, nDPSC expressed 17 out of 52 pluripotency genes we analysed, and the level of expression was comparable to human embryonic stem cells (hESC). Ours is the first group to report comprehensive characterization of nDPSC followed by directed reprogramming to a pluripotent stem cell state. nDPSC yielded hiPSC colonies upon transduction with Sendai virus expressing the pluripotency transcription factors POU5F1, SOX2, c-MYC and KLF4. nDPSC had higher reprogramming efficiency compared to human fibroblasts. nDPSC derived hiPSCs closely resembled hESC in terms of their morphology, expression of pluripotency markers and gene expression profiles. Furthermore, nDPSC derived hiPSCs differentiated into the three germ layers when cultured as embryoid bodies (EB) and by directed differentiation. Based on our findings, nDPSC present a unique marker expression profile compared with adult DPSC and possess higher reprogramming efficiency as compared with dermal fibroblasts thus proving to be more amenable for reprogramming.
| S-EPMC5906561 | biostudies-literature
Project description:BACKGROUND This study was performed to investigate the effect of local injection of asperosaponin VI (ASA VI) on the orthodontic tooth movement in rats. MATERIAL AND METHODS A total of 64 healthy female Sprague-Dawley rats were selected and divided into 2 groups randomly: the ASA VI group and the control group. For the ASA VI group, 10 mg/kg ASA VI solution was injected into buccal submucoperiosteal of bilaterally first maxillary molars, and the same volume of normal saline was given to the control group. The orthodontic force was applied to the maxillary first molars. All rats were sacrificed on days 3, 7, or 14. Tooth movement effects on the periodontium were analyzed through hematoxylin and eosin (H&E) staining, tartrate-resistant acid phosphatase (TRAP) staining and immunohistochemistry analysis. Tooth movement measurements and alveolar bone volumetric changes were analyzed using a micro-computed tomography (CT) scan. Molecular changes were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. RESULTS The ASA VI group presented with a significant increase of tooth movement, osteoclast number, and the expression of osteoclast differentiation factor (ODF) compared with the control group. ASA VI also induced a significant decrease in bone volume and density and an increase in trabecular spacing and RANKL (receptor activator of nuclear factor kappa-B ligand) expression at the compression side. Furthermore, ASA VI stimulated bone formation on the tension side by enhancing OCN (osteocalcin) expression and RUNX2 (runt-related transcription factor 2) expression, increasing bone volume and density and decreasing in trabecular spacing. CONCLUSIONS Injection of ASA VI may accelerate tooth movement via increasing the activity of osteoclasts, stimulating bone resorption at the compression side. Furthermore, ASA VI has a positive effect on bone formation at the tension side.
| S-EPMC7193222 | biostudies-literature