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1.
J Vis Exp ; (206)2024 Apr 26.
Article in English | MEDLINE | ID: mdl-38738893

ABSTRACT

The mechanical property, microhardness, is evaluated in dental enamel, dentin, and bone in oral disease models, including dental fluorosis and periodontitis. Micro-CT (µCT) provides 3D imaging information (volume and mineral density) and scanning electron microscopy (SEM) produces microstructure images (enamel prism and bone lacuna-canalicular). Complementarily to structural analysis by µCT and SEM, microhardness is one of the informative parameters to evaluate how structural changes alter mechanical properties. Despite being a useful parameter, studies on microhardness of alveolar bone in oral diseases are limited. To date, divergent microhardness measurement methods have been reported. Since microhardness values vary depending on the sample preparation (polishing and flat surface) and indentation sites, diverse protocols can cause discrepancies among studies. Standardization of the microhardness protocol is essential for consistent and accurate evaluation in oral disease models. In the present study, we demonstrate a standardized protocol for microhardness analysis in tooth and alveolar bone. Specimens used are as follows: for the dental fluorosis model, incisors were collected from mice treated with/without fluoride-containing water for 6 weeks; for ligature-induced periodontal bone resorption (L-PBR) model, alveolar bones with periodontal bone resorption were collected from mice ligated on the maxillary 2nd molar. At 2 weeks after the ligation, the maxilla was collected. Vickers hardness was analyzed in these specimens according to the standardized protocol. The protocol provides detailed materials and methods for resin embedding, serial polishing, and indentation sites for incisors and alveolar. To the best of our knowledge, this is the first standardized microhardness protocol to evaluate the mechanical properties of tooth and alveolar bone in rodent oral disease models.


Subject(s)
Alveolar Process , Disease Models, Animal , X-Ray Microtomography , Animals , Mice , Alveolar Process/diagnostic imaging , X-Ray Microtomography/methods , Fluorosis, Dental/diagnostic imaging , Fluorosis, Dental/pathology , Hardness , Incisor/diagnostic imaging , Tooth/diagnostic imaging
2.
J Endod ; 50(2): 243-251, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37918795

ABSTRACT

INTRODUCTION: A 65-year-old man had nonsurgical retreatment using an iodoform and calcium hydroxide paste in a maxillary left canine with persistent apical periodontitis. An apical mineralized barrier (AMB) was observed 3-months postoperatively. Unfortunately, the tooth was extracted due to a cementum tear. This provided an opportunity to analyze the AMB histologically, as there is a lack of previous reports on its microstructure. METHODS: After extraction and removal of the granulation tissue from the root surface, the canine was processed, and observed using micro-computed tomography (µCT) and light microscopy. Thereafter, the specimen was resin-embedded specimen was evaluated by scanning electron microscopy, micro-X-ray fluorescence spectroscopy and Raman spectroscopy to understand the mechanism and nature of the AMB formation during apical healing. RESULTS: Nonsurgical retreatment was clinically successful based on the absence of clinical symptoms of apical periodontitis and the radiographic presence of an AMB. The AMB was opaque and could be readily differentiated from dentin under a light microscope. Micro-computed tomography analysis revealed that the AMB had the same mineral density as dentin. Scanning electron microscopy revealed that the AMB had two distinct layers based on the size of the calcified particles. Elemental mapping using micro-X-ray fluorescence spectroscopy showed that the localization of calcium and phosphorus differed between AMB and other areas of biomineralization. Raman spectral mapping revealed that the surface layer of the AMB consisted of collagen, calcium carbonate, and hydroxyapatite. CONCLUSIONS: This study explored new analytical methods for elucidating the apical wound-healing process and the nature of the mineralized repair. The findings provided detailed information on the AMB highlighting a bilaminar structure with high calcium components higher on the inside and a brightness similar to cementum not dentin and the presence of hydroxyapatite.


Subject(s)
Calcium Hydroxide , Hydrocarbons, Iodinated , Periapical Periodontitis , Male , Humans , Aged , Calcium Hydroxide/therapeutic use , Calcium Hydroxide/chemistry , Calcium , X-Ray Microtomography , Hydroxyapatites
3.
Regen Ther ; 24: 377-384, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37711762

ABSTRACT

Introduction: Concentrated growth factor (CGF) is a new-generation autologous platelet concentrate that promotes tissue regeneration and has anti-inflammatory properties. This randomized multicenter trial aimed to evaluate the effects of CGF on bone healing in combination with root-end microsurgery. Methods: Healthy adult patients indicated for root-end microsurgery were randomly assigned to either the CGF or control (no CGF implantation) groups. CGF was implanted into the bone cavity after root-end filling with mineral trioxide aggregate. Clinical and periapical radiographic evaluations were conducted at 1, 3, 6, and 12 months postoperatively, with follow-up cone-beam computed tomography (CBCT) at 6 months. The lesion volume reduction rate was calculated based on data from the preoperative and follow-up CBCT images. Results: A total of 24 patients were enrolled. The treatment success rate was 91.7% and 83.3% on 12-month periapical radiography and 6-month CBCT, respectively, without a significant difference between the two groups. The lesion volume reduction rate in the CGF group (75.6%) was significantly higher than that in the control (61.0%) group. Conclusions: Autologous CGF in conjunction with root-end microsurgery accelerated lesion reduction as observed on CBCT. Administering autologous blood products to stimulate healing in addition to removing the source of infection appears to be a promising treatment option for root-end microsurgery.

4.
Case Rep Dent ; 2023: 2103999, 2023.
Article in English | MEDLINE | ID: mdl-37441169

ABSTRACT

Treatment of large external cervical resorption (ECR) lesions may be compromised, rendering the tooth unrestorable. Intentional replantation is a potential treatment option depending on the site and extent of ECR. We present a case of a large ECR successfully managed with intentional replantation with rotation of the tooth. The female patient consulted the hospital clinic, with an extensive palatal ECR on the maxillary lateral incisor. Routine planar radiographs and cone-beam computed tomography demonstrated a larger palatal than the ECR lesion (Heithersay Class III and Patel's Class 2Bp) not amenable to nonsurgical treatment. Intentional replantation after short-term extrusion was planned. The defect was restored, then a palatal ferrule was achieved by rotating the tooth by 180°. At the 18-month follow-up, the periradicular and periodontal tissues remained healthy, and no other symptoms were reported. In conclusion, this successful video-illustrated clinical case highlights the benefits of intentional replantation in saving teeth with advanced ECR.

5.
Ecotoxicol Environ Saf ; 260: 115089, 2023 Jul 15.
Article in English | MEDLINE | ID: mdl-37271104

ABSTRACT

Perfluorooctanoic acid (PFOA) is an artificial fluorinated organic compound that has generated increased public attention due to its potential health hazards. Unsafe levels of PFOA exposure can affect reproduction, growth and development. During tooth enamel development (amelogenesis), environmental factors including fluoride can cause enamel hypoplasia. However, the effects of PFOA on ameloblasts and tooth enamel formation remain largely unknown. In the present study we demonstrate several PFOA-mediated cell death pathways (necrosis/necroptosis, and apoptosis) and assess the roles of ROS-MAPK/ERK signaling in PFOA-mediated cell death in mouse ameloblast-lineage cells (ALC). ALC cells were treated with PFOA. Cell proliferation and viability were analyzed by MTT assays and colony formation assays, respectively. PFOA suppressed cell proliferation and viability in a dose dependent manner. PFOA induced both necrosis (PI-positive cells) and apoptosis (cleaved-caspase-3, γH2AX and TUNEL-positive cells). PFOA significantly increased ROS production and up-regulated phosphor-(p)-ERK. Addition of ROS inhibitor N-acetyl cysteine (NAC) suppressed p-ERK and decreased necrosis, and increased cell viability compared to PFOA alone, whereas NAC did not change apoptosis. This suggests that PFOA-mediated necrosis was induced by ROS-MAPK/ERK signaling, but apoptosis was not associated with ROS. Addition of MAPK/ERK inhibitor PD98059 suppressed necrosis and increased cell viability compared to PFOA alone. Intriguingly, PD98059 augmented PFOA-mediated apoptosis. This suggests that p-ERK promoted necrosis but suppressed apoptosis. Addition of the necroptosis inhibitor Necrostatin-1 restored cell viability compared to PFOA alone, while pan-caspase inhibitor Z-VAD did not mitigate PFOA-mediated cell death. These results suggest that 1) PFOA-mediated cell death was mainly caused by necrosis/necroptosis by ROS-MAPK/ERK signaling rather than apoptosis, 2) MAPK/ERK signaling plays the dual roles (promoting necrosis and suppressing apoptosis) under PFOA treatment. This is the initial report to indicate that PFOA could be considered as a possible causative factor for cryptogenic enamel malformation. Further studies are required to elucidate the mechanisms of PFOA-mediated adverse effects on amelogenesis.


Subject(s)
Ameloblasts , Mice , Animals , Reactive Oxygen Species/metabolism , Ameloblasts/metabolism , Cell Death , Necrosis
6.
Pharmaceutics ; 14(10)2022 Sep 24.
Article in English | MEDLINE | ID: mdl-36297473

ABSTRACT

Gutta-percha points and root canal sealers have been used for decades in endodontics for root canal obturation. With techniques such as single cone methods, the amount of sealer is larger, making their properties more critical. However, relatively few reports have comprehensively evaluated their biological effects. To this end, we evaluated three types of sealers, zinc oxide-fatty acid-, bio-glass- and methacrylate resin-containing sealers were considered. Their biological effects were evaluated using a rat subcutaneous implantation model. Each sealer was loaded inside a Teflon tube and implanted subcutaneously in the backs of rats. Inflammatory cells were observed around all samples 7 days after implantation and reduced after 28 days. Our results revealed that all samples were in contact with the subcutaneous tissue surrounding the sealer. Additionally, Ca and P accumulation was observed in only the bio-glass-containing sealer. Furthermore, each of the three sealers exhibited unique immune and inflammatory modulatory effects. In particular, bio-glass and methacrylate resin sealers were found to induce variable gene expression in adjacent subcutaneous tissues related to angiogenesis, wound healing, muscle tissue, and surrounding subcutaneous tissue. These results may help to understand the biological impacts of root canal sealers on surrounding biological tissues, guiding future research and comparisons with new generations of materials.

7.
Oral Dis ; 28(3): 745-755, 2022 Apr.
Article in English | MEDLINE | ID: mdl-33539626

ABSTRACT

OBJECTIVE: The main aim of this study was to elucidate the effects of advanced glycation end products (AGEs) on the calcification of cultured rat dental pulp cells (RDPCs) and to investigate the crystallisation ability of glycated collagen. MATERIALS AND METHODS: AGEs were prepared via non-enzymatic glycation of a dish coated with type I collagen using dl-glyceraldehyde. To investigate the effects of AGEs on RDPCs, we performed WST-1 and lactate dehydrogenase assays; alkaline phosphatase, Alizarin Red S and immunohistochemical staining; and real-time quantitative reverse transcription PCR. In addition, we performed crystallisation experiments on glycated collagen. All microstructures were analysed using scanning electron microscopy/energy-dispersive X-ray spectroscopy and transmission electron microscopy/diffraction pattern analysis. RESULTS: AGEs did not affect the proliferation or differentiation of RDPCs, but enhanced the calcification rate and cytotoxicity. No major calcification-related genes or proteins were involved in these calcifications, and glycated collagen was found to exhibit a negative polarity and form calcium phosphate crystals. Cytotoxicity due to drastic changes in the concentration of pericellular ions led to dystrophic calcification, assumed to represent an aspect of diabetic pulp calcifications. CONCLUSION: Glycated collagen-containing AGEs provide a nurturing environment for crystallisation and have a significant effect on the early calcification of RDPCs.


Subject(s)
Dental Pulp Calcification , Diabetes Mellitus , Animals , Cell Differentiation , Cells, Cultured , Dental Pulp , Diabetes Mellitus/metabolism , Glycation End Products, Advanced/genetics , Glycation End Products, Advanced/metabolism , Glycation End Products, Advanced/pharmacology , Rats
8.
Dent Mater ; 38(2): 294-308, 2022 02.
Article in English | MEDLINE | ID: mdl-34953627

ABSTRACT

OBJECTIVE: Surface pre-reacted glass fillers (S-PRG) can release different types of ions and in our previous study, we modified these fillers with lithium chloride (S-PRG/Li-100 mM) to induce reparative dentin formation by activating the Wnt/ß-catenin signaling pathway. Here, we assessed the biological performance of S-PRG/Li-100 mM and compared it with that of mineral trioxide aggregate (MTA) and S-PRG without additives. METHODS: In vivo studies were conducted on male Wistar rats using Masson's trichrome staining in pulp-capped molars. The test materials were implanted subcutaneously to evaluate their capacity for vascularization and biocompatibility. The ability of the test materials to form apatite was tested by immersing them in simulated body fluid. Rhodamine-B staining was conducted to assess their sealing ability in bovine teeth, while their antibacterial activity was evaluated against Streptococcus mutans and Lactobacillus casei in terms of colony-forming units and by live/dead staining. RESULTS: Masson's trichrome staining and tissue-implantation tests confirmed the biocompatibility of S-PRG/Li-100 mM and it was similar to that of MTA and S-PRG; inflammation regression was observed 14 days after operation in the subcutaneous tissues. S-PRG/Li-100 mM promoted the formation of apatite on its surface. Both the S-PRG groups showed higher sealing capability and bactericidal/bacteriostatic activity against oral bacterial biofilms than MTA. SIGNIFICANCE: Lithium-containing surface pre-reacted glass cements exhibit better antibacterial and sealing capabilities than MTA, suggesting their potential as high-performance direct pulp-capping materials.


Subject(s)
Dental Pulp Capping , Lithium , Animals , Cattle , Glass , Glass Ionomer Cements/pharmacology , Male , Rats , Rats, Wistar , Silicates/pharmacology , Surface Properties
9.
Arch Oral Biol ; 128: 105172, 2021 Aug.
Article in English | MEDLINE | ID: mdl-34058725

ABSTRACT

OBJECTIVE: The position and size of the major cusps in mammalian molars are arranged in a characteristic pattern that depends on taxonomy. In humans, the cusp which locates distally within each molar is smaller than the mesially located cusp, which is referred to as "distal reduction". Although this concept has been well-recognized, it is still unclear how this reduction occurs. Current study examined whether senescence-accelerating mouse prone 8 (SAMP8) mice could be a possible animal model for studying how the mammalian molar cusp size is determined. DESIGN: SAMP8 mice were compared with parental control (SAMR1) mice. Microcomputed tomography images of young and aged mice were captured to observe molar cusp morphologies. Cusp height from cement-enamel junction and mesio-distal length of molars were measured. The statistical comparison of the measurements was performed by Mann-Whitney U test. RESULTS: SAMP8 mice showed reduced development of the disto-lingual cusp (entoconid) of lower second molar when compared with SAMR1 mice. The enamel thickness and structure was disturbed at entoconid, and aged SAMP8 mice displayed severe wear of the entoconid in lower second molar. These phenotypes were observed on both sides of the lower second molar. CONCLUSIONS: In addition to the general senescence phenotype observed in SAMP8 mice, this strain may genetically possess molar cusp phenotypes which is determined prenatally. Further, SAMP8 mice would be a potential model strain to study the genetic causes of the distal reduction of molar cusp size.


Subject(s)
Molar , Tooth , Animals , Dental Cementum , Disease Models, Animal , Mice , Molar/diagnostic imaging , X-Ray Microtomography
10.
Sci Rep ; 10(1): 15342, 2020 09 15.
Article in English | MEDLINE | ID: mdl-32929155

ABSTRACT

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

11.
Polymers (Basel) ; 12(4)2020 Apr 17.
Article in English | MEDLINE | ID: mdl-32316615

ABSTRACT

Vital pulp therapy is an important endodontic treatment. Strategies using growth factors and biological molecules are effective in developing pulp capping materials based on wound healing by the dentin-pulp complex. Our group developed biodegradable viscoelastic polymer materials for tissue-engineered medical devices. The polymer contents help overcome the poor fracture toughness of hydroxyapatite (HAp)-facilitated osteogenic differentiation of pulp cells. However, the composition of this novel polymer remained unclear. This study evaluated a novel polymer composite, P(CL-co-DLLA) and HAp, as a direct pulp capping carrier for biological molecules. The biocompatibility of the novel polymer composite was evaluated by determining the cytotoxicity and proliferation of human dental stem cells in vitro. The novel polymer composite with BMP-2, which reportedly induced tertiary dentin, was tested as a direct pulp capping material in a rat model. Cytotoxicity and proliferation assays revealed that the biocompatibility of the novel polymer composite was similar to that of the control. The novel polymer composite with BMP-2-induced tertiary dentin, similar to hydraulic calcium-silicate cement, in the direct pulp capping model. The BMP-2 composite upregulated wound healing-related gene expression compared to the novel polymer composite alone. Therefore, we suggest that novel polymer composites could be effective carriers for pulp capping.

12.
J Clin Med ; 8(9)2019 Sep 11.
Article in English | MEDLINE | ID: mdl-31514356

ABSTRACT

The induction of tissue mineralization and the mechanism by which surface pre-reacted glass-ionomer (S-PRG) cement influences pulpal healing remain unclear. We evaluated S-PRG cement-induced tertiary dentin formation in vivo, and its effect on the pulp cell healing process in vitro. Induced tertiary dentin formation was evaluated with micro-computed tomography (µCT) and scanning electron microscopy (SEM). The distribution of elements from the S-PRG cement in pulpal tissue was confirmed by micro-X-ray fluorescence (µXRF). The effects of S-PRG cement on cytotoxicity, proliferation, formation of mineralized nodules, and gene expression in human dental pulp stem cells (hDPSCs) were assessed in vitro. µCT and SEM revealed that S-PRG induced tertiary dentin formation with similar characteristics to that induced by hydraulic calcium-silicate cement (ProRoot mineral trioxide aggregate (MTA)). µXRF showed Sr and Si ion transfer into pulpal tissue from S-PRG cement. Notably, S-PRG cement and MTA showed similar biocompatibility. A co-culture of hDPSCs and S-PRG discs promoted mineralized nodule formation on surrounding cells. Additionally, S-PRG cement regulated the expression of genes related to osteo/dentinogenic differentiation. MTA and S-PRG regulated gene expression in hDPSCs, but the patterns of regulation differed. S-PRG cement upregulated CXCL-12 and TGF-ß1 gene expression. These findings showed that S-PRG and MTA exhibit similar effects on dental pulp through different mechanisms.

13.
Cells ; 8(9)2019 08 29.
Article in English | MEDLINE | ID: mdl-31470634

ABSTRACT

Dentin consists of inorganic hard tissue and organic dentin matrix components (DMCs). Various kinds of bioactive molecules are included in DMCs and some of them can be released after digestion by endogenous matrix metalloproteinases (MMPs) in the caries region. Digested DMCs induced by MMP20 have been reported to promote pulpal wound healing processes, but the released critical molecules responsible for this phenomenon are unclear. Here, we identified protein S100-A7 as a critical molecule for pulpal healing in digested DMCs by comprehensive proteomic approaches and following pulp capping experiments in rat molars. In addition, immunohistochemical results indicated the specific distribution of S100-A7 and receptor for advanced glycation end-products (RAGE) as receptor for S100-A7 in the early stage of the pulpal healing process, and following accumulation of CD146-positive stem cells in wounded pulp. Our findings indicate that protein S100-A7 released from dentin by MMP20 might play a key role in dentin pulp regeneration.


Subject(s)
Dental Pulp Capping/methods , Dental Pulp Exposure/therapy , Dentinogenesis , S100 Calcium Binding Protein A7/therapeutic use , Wound Healing , Animals , Dental Pulp/metabolism , Dentin/metabolism , Humans , Male , Rats , Rats, Wistar
14.
Acta Biomater ; 96: 594-604, 2019 09 15.
Article in English | MEDLINE | ID: mdl-31212112

ABSTRACT

Surface pre-reacted glass (S-PRG) fillers are new bioactive molecules used in dental clinic work to fill tooth defects. These fillers release various types of ions (Al+3, BO-3, Na+, SiO3-2, Sr+2 and F-) and exhibit high biocompatibility, antibacterial capability, reduced plaque accumulation, and enhanced osteoblast differentiation. We previously showed that cement of S-PRG fillers could induce tertiary dentin formation in rat models. Previous work also showed that lithium ions can activate the Wnt/ß-catenin signaling pathway in vitro and induce dentin formation in pulpotomized teeth in vivo. In the current study, we sought to enhance the effect of S-PRG cement by incorporating LiCl. We show that treatment of human dental pulp stem cells with eluates from S-PRG/LiCl combination cements leads to an upregulation in cell migration, differentiation, and mineralization in vitro. In pulp-capping animal trials, we found that S-PRG/LiCl cements could induce tertiary dentin formation 28-days post-capping. At 7 days post-capping, we identified both ß-catenin and Axin2 expression using immunofluorescence, indicative of Wnt/ß-catenin signaling activity. In conclusion, S-PRG/LiCl cement is highly effective in promoting human dental pulp stem cells profiles and in enhancing reparative dentin formation in rat teeth through activation of the Wnt/ß-catenin canonical signaling pathway. STATEMENT OF SIGNIFICANCE: This is the first study to assess the behavior of S-PRG fillers containing lithium ions on human dental pulp stem cells. We show that this new combination cement promotes positive cell responses by activating the endogenous Wnt/ß-catenin signaling pathway in the pulp. The Wnt/ß-catenin canonical signaling pathway is involved in many developmental and wound healing processes. The released lithium ions from the S-PRG cement were systematically detected <0.01 mmol/L in our rat model. But it was efficient to induce tertiary dentin formation at the defect site. Since this novel bioactive cement is potentially a promising material for clinical pulp regenerative therapy, future human clinical trials will be needed.


Subject(s)
Dental Pulp Capping , Dentin/metabolism , Glass/chemistry , Lithium/chemistry , Models, Biological , Stem Cells/metabolism , Wnt Signaling Pathway , Animals , Humans , Male , Rats , Rats, Wistar
15.
Dent Mater J ; 38(5): 743-749, 2019 Oct 02.
Article in English | MEDLINE | ID: mdl-31231104

ABSTRACT

Dual-cured resin-based composites are gaining popularity as core build-up materials. Physical and elastoplastic characteristics of new experimental core build-up materials with variable filler contents (+2.5 and +5 wt%) were investigated using classic macroexperiments and nanoindentation. Flexural fracture strength increased from 91.7±11.8 to 114.1±9.1 and 116.6±14.7 MPa in the +2.5 and +5 wt% groups, respectively; similarly, elastic moduli increased from 12.6±0.9 to 15.4±1.2 and 15.3±2.0 MPa, respectively. Fracture toughness increased from 1.82±0.60 to 2.28±0.53 and 2.67±0.88 MPa•m1/2 for the +2.5 and +5 wt% groups, respectively; indentation hardness increased significantly from 0.45±0.03 to 0.55±0.04 and 0.60±0.10 GPa, respectively. The addition of +5 wt% filler content led to a mechanically superior material; the addition of +2.5 wt% filler led to better reliability.


Subject(s)
Composite Resins , Dental Materials , Hardness , Materials Testing , Pliability , Reproducibility of Results
16.
Clin Oral Investig ; 23(4): 1723-1731, 2019 Apr.
Article in English | MEDLINE | ID: mdl-30159805

ABSTRACT

OBJECTIVES: To evaluate new pulp capping cements containing surface pre-reacted glass ionomer (S-PRG) filler and to investigate ion release kinetics and pH shift of eluates from the cement. MATERIALS AND METHODS: Molars of Wistar rats were directly pulp capped using three kinds of cement containing S-PRG filler and mineral tri-oxide aggregate (MTA) was used as a control. After 1, 2, or 4 weeks, histological evaluation was performed and differences of tertiary dentin formation were analyzed. Release of Sr2+, BO33-, SiO32-, Na+, and Al3+ ions was determined by inductively coupled plasma-atomic emission spectrometry, and F- ion release was measured using a fluoride ion selective electrode. The pH of the eluate from each cement after mixing was measured with a pH electrode. RESULTS: One of S-PRG cements promoted tertiary dentin formation to the same extent as the control (p > 0.05) and it showed a tendency of less inflammatory response. This cement released more BO33- and SiO32-, but less Sr2+, Na+, and F- than other S-PRG specimens. Each cement recovered nearly neutral compared with glass ionomer cement. CONCLUSIONS: S-PRG cement induced tertiary dentin formation based on multiple ion releases, suggesting that it is suitable as a pulp capping material. CLINICAL RELEVANCE: This new material can be an alternative pulp capping agent to MTA.


Subject(s)
Dental Pulp Capping , Glass Ionomer Cements , Pulp Capping and Pulpectomy Agents , Acrylic Resins , Aluminum Compounds , Animals , Calcium Compounds , Dentin , Drug Combinations , Molar , Oxides , Rats , Rats, Wistar , Silicates , Silicon Dioxide
17.
Sci Rep ; 8(1): 10690, 2018 Jul 16.
Article in English | MEDLINE | ID: mdl-30013085

ABSTRACT

Dentin is primarily composed of hydroxyapatite crystals within a rich organic matrix. The organic matrix comprises collagenous structural components, within which a variety of bioactive molecules are sequestered. During caries progression, dentin is degraded by acids and enzymes derived from various sources, which can release bioactive molecules with potential reparative activity towards the dentin-pulp complex. While these molecules' repair activities in other tissues are already known, their biological effects are unclear in relation to degradation events during disease in the dentin-pulp complex. This study was undertaken to investigate the effects of dentin matrix components (DMCs) that are partially digested by matrix metalloproteinases (MMPs) in vitro and in vivo during wound healing of the dentin-pulp complex. DMCs were initially isolated from healthy dentin and treated with recombinant MMPs. Subsequently, their effects on the behaviour of primary pulp cells were investigated in vitro and in vivo. Digested DMCs modulated a range of pulp cell functions in vitro. In addition, DMCs partially digested with MMP-20 stimulated tertiary dentin formation in vivo, which exhibited a more regular tubular structure than that induced by treatment with other MMPs. Our results indicate that MMP-20 may be especially effective in stimulating wound healing of the dentin-pulp complex.


Subject(s)
Dental Caries/therapy , Dental Pulp Capping/methods , Dentin/metabolism , Dentinogenesis , Matrix Metalloproteinase 20/metabolism , Adolescent , Adult , Animals , Cells, Cultured , Dental Caries/pathology , Dental Pulp/cytology , Dental Pulp/pathology , Dental Pulp/physiology , Dentin/chemistry , Dentin/cytology , Dentin/pathology , Disease Models, Animal , Female , Humans , Male , Primary Cell Culture , Pulp Capping and Pulpectomy Agents/metabolism , Rats , Rats, Wistar , Wound Healing/physiology , Young Adult
18.
Clin Oral Investig ; 22(8): 2879-2887, 2018 Nov.
Article in English | MEDLINE | ID: mdl-29435662

ABSTRACT

OBJECTIVES: We evaluated a novel micro-computed tomography (micro-CT) assessment for quality and quantity of dentin repair, which is difficult to visualize by histological analysis, after direct pulp capping under standardized cavity preparation. MATERIALS AND METHODS: Standardized cavities were prepared on Wistar rats and direct pulp capping was performed using two commercial bioceramics, ProRoot MTA, and iRoot BP Plus. After 2 or 4 weeks, quality and quantity of tertiary dentin formation were evaluated using high-resolution micro-CT analyses including dentin mineral density, dentin mineral contents, compactness and integrity of tertiary dentin, and dentin volume with/without void space. Reproducibility of micro-CT analyses was confirmed by histological evaluation of the same specimen. RESULTS: The exposed pulp area sizes were similar between iRoot BP Plus and ProRoot MTA. Micro-CT analysis of 2-week samples showing compactness of tertiary dentin was significantly higher in iRoot BP Plus than ProRoot MTA (p < 0.05). Tertiary dentin volume without void space, dentin mineral contents, and density were not significantly different between the groups. In 4-week samples, a significant increase was observed in dentin mineral density, compactness, and dentin volume with/without void space induced by iRoot BP Plus (p < 0.05). Micro-CT analysis of tertiary dentin integrity demonstrated that some ProRoot MTA specimens had small defects and lacked continuity (6/512 images). No defects were observed with iRoot BP Plus. CONCLUSIONS: Micro-CT analysis was confirmed as an accurate, objective, and inclusive approach for evaluating quality and quantity of dentin repair. CLINICAL RELEVANCE: These multifaceted approaches to evaluate pulp capping materials may accelerate review processes, ultimately improving vital pulp therapy.


Subject(s)
Dental Pulp Capping/methods , Dentin/diagnostic imaging , Pulp Capping and Pulpectomy Agents/pharmacology , X-Ray Microtomography/methods , Animals , Dentin/chemistry , Rats , Rats, Wistar , Reproducibility of Results , Root Canal Filling Materials , Silicates
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