Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 9 de 9
Filter
Add more filters










Database
Language
Publication year range
1.
Int Endod J ; 52(1): 28-43, 2019 Jan.
Article in English | MEDLINE | ID: mdl-29869795

ABSTRACT

AIM: To investigate whether static magnetic fields (SMFs) have a positive effect on the migration and dentinogenesis of dental pulp stem cells (DPSCs) to promote reparative dentine formation. METHODOLOGY: In vitro scratch assays and a traumatic pulp exposure model were performed to evaluate the effect of 0.4-Tesla (T) SMF on DPSC migration. The cytoskeletons of the DPSCs were identified by fluorescence immunostaining and compared with those of a sham-exposed group. Dentinogenic evaluation was performed by analysing the expressions of DMP-1 and DSPP marker genes using a quantitative real-time polymerase chain reaction (qRT-PCR) process. Furthermore, the formation of calcified deposits was examined by staining the dentinogenic DPSCs with Alizarin Red S dye. Finally, the role played by the p38 MAPK signalling pathway in the migration and dentinogenesis of DPSCs under 0.4-T SMF was investigated by incorporating p38 inhibitor (SB203580) into the in vitro DPSC experiments. The Student's t-test and the Kruskal-Wallis test followed by Dunn's post hoc test with a significance level of P < 0.05 were used for statistical analysis. RESULTS: The scratch assay results revealed that the application of 0.4-T SMF enhanced DPSCs migration towards the scratch wound (P < 0.05). The cytoskeletons of the SMF-treated DPSCs were found to be aligned perpendicular to the scratch wound. After 20 days of culture, the SMF-treated group had a greater number of out-grown cells than the sham-exposed group (nonmagnetized control). For the SMF-treated group, the DMP-1 (P < 0.05) and DSPP genes (P < 0.05), analysed by qRT-PCR, exhibited a higher expression. The distribution of calcified nodules was also found to be denser in the SMF-treated group when stained with Alizarin Red S dye (P < 0.05). Given the incorporation of p38 inhibitor SB203580 into the DPSCs, cell migration and dentinogenesis were suppressed. No difference was found between the SMF-treated and sham-exposed cells (P > 0.05). CONCLUSION: 0.4-T SMF enhanced DPSC migration and dentinogenesis through the activation of the p38 MAPK-related pathway.


Subject(s)
Dental Pulp/radiation effects , Dentin, Secondary/growth & development , Dentin, Secondary/radiation effects , Dentinogenesis/radiation effects , Magnetic Fields , Signal Transduction/radiation effects , Stem Cells , p38 Mitogen-Activated Protein Kinases/metabolism , Cell Differentiation/radiation effects , Cell Movement/radiation effects , Cell Proliferation/radiation effects , Cytoskeleton , Dental Pulp/cytology , Dental Pulp/growth & development , Dental Pulp/metabolism , Dentin, Secondary/cytology , Dentin, Secondary/metabolism , Extracellular Matrix Proteins/genetics , Extracellular Matrix Proteins/metabolism , Gene Expression , Humans , Phosphoproteins/genetics , Phosphoproteins/metabolism , Sialoglycoproteins/genetics , Sialoglycoproteins/metabolism
2.
Oral Dis ; 22(5): 399-405, 2016 Jul.
Article in English | MEDLINE | ID: mdl-26866618

ABSTRACT

OBJECTIVES: GaAlAs lasers induce pulp mineralization by promoting reparative dentinogenesis. This study analyzed the expression of dentin matrix protein 1 (DMP1) and osteopontin in GaAlAs laser-irradiated rat molars, to examine the hypothesis that these proteins play a role in the laser-induced reparative dentinogenic process. MATERIALS AND METHODS: The mesial surfaces of the upper first molars of 8-week-old Wistar rats were irradiated with a pulsed GaAlAs laser. After 1-14 days, mRNA expression of DMP1 and osteopontin in the coronal pulp was analyzed using real-time PCR. DMP1, osteopontin, and heat shock protein 25 (HSP25) were immunolocalized at 1-21 days. RESULTS: The pulp exhibited a degenerative zone in its mesial portion on days 1-3, and progressive formation of reparative dentin lined with HSP25-immunoreactive odontoblast-like cells, from day 7 onwards. DMP1 and osteopontin mRNA expression were significantly upregulated on days 1-7 and 3-7, respectively. From day 7 onwards, DMP1 and osteopontin immunoreactivity colocalized along the boundary between the primary and reparative dentin. CONCLUSION: GaAlAs laser irradiation of rat molars induced upregulated DMP1 and osteopontin mRNA expression in the coronal pulp, followed by the formation of reparative dentin and the colocalization of DMP1 and osteopontin immunoreactivity at the site at which this tissue first appeared.


Subject(s)
Dentin, Secondary/metabolism , Dentin, Secondary/radiation effects , Extracellular Matrix Proteins/biosynthesis , Lasers, Semiconductor , Molar/radiation effects , Osteopontin/biosynthesis , Phosphoproteins/biosynthesis , Animals , Dental Pulp/cytology , Dental Pulp/physiology , Extracellular Matrix Proteins/radiation effects , HSP27 Heat-Shock Proteins/biosynthesis , Immunohistochemistry , Male , Molar/cytology , Molar/metabolism , Odontoblasts/metabolism , Odontoblasts/radiation effects , Osteopontin/radiation effects , Phosphoproteins/radiation effects , Rats , Rats, Wistar , Up-Regulation/radiation effects
3.
J Endod ; 39(9): 1147-50, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23953288

ABSTRACT

INTRODUCTION: In vital pulp therapy such as direct pulp capping, clinical success rates depend on achieving hemostasis in exposed pulp tissue. For hemostasis of exposed pulp tissue, gentle pressure by cotton pellets moistened with sodium hypochlorite is most commonly used. However, more rapid and reliable methods are necessary. Therefore, we focused on high-frequency radio waves (HRW). METHODS: To evaluate reparative dentin induction by HRW, we used a rat direct pulp capping model and performed hemostasis by using HRW of several strengths, covering the pulp with calcium hydroxide as a direct capping agent. After 14 or 28 days, rats were killed, and reparative dentin and pulp inflammation were investigated histologically. RESULTS: Radio wave-induced hemostasis required less time when compared with the control group. Reparative dentin with regularly arranged dentinal tubules was observed in the HRW group. CONCLUSIONS: HRW induce hemostasis and produce high-quality reparative dentin and reduced pulpal inflammation.


Subject(s)
Dental Pulp Capping/methods , Hemostatic Techniques , Radiofrequency Therapy , Animals , Calcium Hydroxide/therapeutic use , Dental Pulp Exposure/drug therapy , Dental Pulp Exposure/radiotherapy , Dentin, Secondary/drug effects , Dentin, Secondary/pathology , Dentin, Secondary/radiation effects , Hydrogen Peroxide/therapeutic use , Male , Models, Animal , Odontoblasts/drug effects , Odontoblasts/pathology , Odontoblasts/radiation effects , Pulp Capping and Pulpectomy Agents/therapeutic use , Pulpitis/classification , Pulpitis/prevention & control , Rats , Rats, Wistar , Sodium Hypochlorite/therapeutic use , Time Factors
4.
Odontology ; 99(1): 34-44, 2011 Jan.
Article in English | MEDLINE | ID: mdl-21271324

ABSTRACT

This study examined the effects of direct pulp capping treatment using super-pulsed CO2 laser preirradiation on the wound healing process of exposed rat pulp on days 1, 3, 7, 14, and 28 postoperatively. Group 1 was irradiated with a CO2 laser and directly capped with a self-etching adhesive system. The laser was operated in super-pulse mode (pulse duration, 200 µs; interval, 5800 µs; 0.003 J/pulse). The irradiation conditions were a power output of 0.5 W, an irradiation time of 3 s, and repeat mode (10 ms of irradiation at 10-ms intervals for a total beam exposure time of 1.5 s), defocused beam diameter of 0.74 mm (approximately 20 mm from the exposed pulp surface), energy density of 0.698 J/cm² per pulse, total applied energy of 0.75 J, and an activated air-cooling system. Group 2 was capped with the self-etching adhesive system. Group 3 was capped with commercially available calcium hydroxide, and the self-etching adhesive system was applied to the cavity. The following parameters were evaluated: pulp tissue disorganization, inflammatory cell infiltration, reparative dentin formation, and bacterial penetration. The results were statistically analyzed using the Kruskal-Wallis test for differences among the groups at each observation period (P < 0.05). There were no significant differences among the experimental groups in any parameters at any postoperative period (P > 0.05). CO2 laser irradiation was effective in arresting hemorrhaging but showed a tendency to delay reparative dentin formation compared with the application of calcium hydroxide.


Subject(s)
Dental Pulp Capping/methods , Dental Pulp Exposure/therapy , Dental Pulp/radiation effects , Dentin, Secondary/metabolism , Wound Healing/radiation effects , Animals , Calcium Hydroxide/therapeutic use , Carbon Dioxide , Dental Leakage/prevention & control , Dental Pulp/metabolism , Dentin, Secondary/radiation effects , Extracellular Matrix Proteins/biosynthesis , HSP47 Heat-Shock Proteins/biosynthesis , Hemostatic Techniques , Lasers, Gas , Male , Phosphoproteins/biosynthesis , Rats , Rats, Sprague-Dawley , Resin Cements/therapeutic use , Root Canal Filling Materials/therapeutic use , Transforming Growth Factor beta1/metabolism
5.
Article in English | MEDLINE | ID: mdl-11174601

ABSTRACT

OBJECTIVE: The purpose of this study was to evaluate the pulpal response to the Er:YAG laser after accidental exposure of the pulp. STUDY DESIGN: Cavities were prepared, and pulps were exposed by either Er:YAG laser or mechanically by a slow-speed conventional handpiece (control group) in 76 maxillary first molars of male Wistar rats. Rats were killed immediately, at 3 days, 1 week, and 2 weeks. Histopathologic examinations of the pulp at the exposure site were performed and evaluated with the Mann-Whitney U test (P <.05). RESULTS: The Er:YAG laser group showed no bleeding and no dentin chips at the exposure site immediately after pulp exposure. However, they displayed an area of blood extravasation near the exposure site. Subsequently, the Er:YAG laser group formed dentin bridges at the exposure site more frequently than the control group. The Er:YAG laser group demonstrated more reparative dentin formation near the exposure site than the control group, especially at 2 weeks, which was highly significant (P <.01). CONCLUSION: According to the results of this study, Er:YAG laser-exposed pulp tissue demonstrated good healing capacity with the formation of a dentin bridge and reparative dentin. However, further investigations are suggested to study the effect of the blood extravasation, which appeared near the laser exposure sites.


Subject(s)
Dental Pulp/radiation effects , Lasers , Aluminum Silicates , Animals , Calcium Hydroxide/therapeutic use , Dental Cavity Preparation/adverse effects , Dental Cavity Preparation/instrumentation , Dental Pulp/pathology , Dental Pulp Capping , Dental Pulp Exposure/physiopathology , Dentin/pathology , Dentin/radiation effects , Dentin, Secondary/pathology , Dentin, Secondary/radiation effects , Erbium , Follow-Up Studies , Hemorrhage/pathology , Hemorrhage/prevention & control , Male , Minerals/therapeutic use , Molar , Rats , Rats, Wistar , Statistics, Nonparametric , Wound Healing/radiation effects , Yttrium
6.
J Endod ; 26(2): 95-9, 2000 Feb.
Article in English | MEDLINE | ID: mdl-11194381

ABSTRACT

The purpose of this study was to investigate histopathological changes in the dental pulp after Er:YAG laser irradiation compared with those after high-speed drill preparation. For evaluation, repair of nerve fibers was observed using an immunohistochemical technique. There was no significant difference between the remaining dentin thickness in either cases. (Mann-Whitney U test). In the Er:YAG laser group a marked fibroblast proliferation and the formation of reparative dentin were observed relative to the high-speed drill group. The time course of the increase and decrease in calcitonin gene-related peptide-immunoreactive fibers in the high-speed drill group was similar to that of previous reports. In the Er:YAG laser group an increase in calcitonin gene-related peptide-immunoreactive fibers was seen earlier than in the high-speed drill group, and 7 days after operation these fibers decreased to control level. The results suggested that the Er:YAG laser leads to pulpal repair earlier than the high-speed drill.


Subject(s)
Dental Cavity Preparation/methods , Dental Pulp/radiation effects , Laser Therapy , Nerve Fibers/radiation effects , Aluminum Silicates , Analysis of Variance , Animals , Calcitonin Gene-Related Peptide/analysis , Cell Division/radiation effects , Dental Cavity Preparation/classification , Dental Cavity Preparation/instrumentation , Dental High-Speed Equipment , Dental Pulp/innervation , Dentin/innervation , Dentin/pathology , Dentin/radiation effects , Dentin, Secondary/pathology , Dentin, Secondary/radiation effects , Erbium , Fibroblasts/pathology , Fibroblasts/radiation effects , Immunohistochemistry , Male , Nerve Fibers/ultrastructure , Neurogenic Inflammation/pathology , Rats , Rats, Sprague-Dawley , Statistics, Nonparametric , Time Factors , Wound Healing , Yttrium
7.
J Clin Laser Med Surg ; 14(1): 37-42, 1996 Feb.
Article in English | MEDLINE | ID: mdl-9484099

ABSTRACT

This study evaluated the clinical, radiographic, and histologic effects of the HGM PC Oralase argon laser on vital pulps of swine teeth. Pulpotomies were performed in vivo on 42 primary teeth from three young pigs and observed for 7 or 60 days. For each time period nine experimental teeth received an argon laser dose of 1 W, 2 sec (24.88 J/cm2), and nine experimental teeth received a dose of 2 W, 2 sec (49.74 J/cm2). Controls consisted of three teeth for each time period and did not receive exposure from the argon laser. There were no significant differences noted between the two energy densities with respect to clinical, radiographic, or histological parameters for either time period. All soft tissues remained normal and all teeth exhibited normal mobility at weekly assessments. Other than physiologic root resorption, there were no differences in pre- and postoperative radiographs in the 7 day sample; calcifications coinciding to dentinal bridges were visible radiographically in 8 of the 60-day samples. Reparative dentin formation was noted histologically in a total of 9 roots in the 7-day group and in 13 roots in the 60-day group. With the exception of teeth which had early restoration loss with resultant bacterial contamination, all other pulps appeared to retain their vitality and capability of normal pulpal healing. Use of the argon laser at the parameters described in this study did not appear to be detrimental to pulpal tissues.


Subject(s)
Laser Therapy , Pulpotomy/methods , Tooth, Deciduous/radiation effects , Animals , Argon , Dental Pulp/radiation effects , Dental Pulp Necrosis/etiology , Dentin, Secondary/radiation effects , Evaluation Studies as Topic , Lasers/adverse effects , Pulpitis/etiology , Statistics, Nonparametric , Swine
8.
J Dent ; 20(2): 100-7, 1992 Apr.
Article in English | MEDLINE | ID: mdl-1564179

ABSTRACT

The reaction of enamel, dentine and pulpal tissues to exposure from a laser beam has been shown to depend on the type of laser medium used. The objective of this study was to examine the pulpal response in rat molars after external enamel surface treatment with either an Ar:F excimer laser or acid-gel application. Maxillary right molar occlusal surfaces in 22 animals were irradiated (energy density = 45.0 J/cm2). Maxillary left molar occlusal surfaces were treated with 37 per cent phosphoric acid for 30 s. Untreated mandibular right molars served as controls. At two postoperative time periods (1 and 6 weeks), molars were removed, sectioned, stained (H&E) and scored. Data analysis indicated no significant difference between Ar:F irradiation and controls at 1 week. Treatment with laser or acid-etching left a similar degree of pathosis at 1 and 6 weeks. Although the Ar:F excimer laser produced a more exaggerated pulp response than controls at 6 weeks, tissue vitality was maintained. The Ar:F excimer laser may be useful for ablating vital tooth structure since pulpal tissue in rat molars exhibited no damage in response to low-power irradiation.


Subject(s)
Acid Etching, Dental , Dental Enamel/pathology , Dental Pulp/pathology , Light Coagulation , Odontoblasts/pathology , Phosphoric Acids/pharmacology , Animals , Dental Enamel/drug effects , Dental Enamel/radiation effects , Dental Pulp/drug effects , Dental Pulp/radiation effects , Dental Pulp Necrosis/pathology , Dentin/drug effects , Dentin/pathology , Dentin/radiation effects , Dentin, Secondary/drug effects , Dentin, Secondary/pathology , Dentin, Secondary/radiation effects , Light Coagulation/methods , Male , Microscopy, Electron, Scanning , Odontoblasts/drug effects , Odontoblasts/radiation effects , Rats , Rats, Inbred Strains , Time Factors
9.
J Oral Pathol ; 17(1): 26-9, 1988 Jan.
Article in English | MEDLINE | ID: mdl-3131506

ABSTRACT

The effect of the radioprotector 2-mercaptopropionylglycine (MPG) in preventing the synthesis of radiation-induced osteodentin was examined. Fifty rats were exposed to single x-ray doses of between 3 and 19 Gy localized to the maxillary incisor growth centers. Half of the animals received an injection of MPG before irradiation while saline was administered to the other rats. MPG produced statistically significant reductions in the severity of osteodentin generation, but not its frequency, at some radiation levels. The nature of osteodentin and possible mechanisms of chemical radioprotection by MPG are discussed.


Subject(s)
Amino Acids, Sulfur/therapeutic use , Dental Pulp/radiation effects , Dentin, Secondary/radiation effects , Radiation-Protective Agents/therapeutic use , Radiography, Dental/adverse effects , Tiopronin/therapeutic use , Animals , Cell Differentiation/radiation effects , Dental Pulp/pathology , Dentin, Secondary/pathology , Incisor/radiation effects , Rats
SELECTION OF CITATIONS
SEARCH DETAIL
...