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OBJECTIVE@#To explore the histological structure of the deciduous teeth and the tooth germs of Tibetan miniature pigs for studies of dental tissue diseases and tooth regeneration.@*METHODS@#The structure of the deciduous teeth of Tibetan miniature pigs was observed by X-ray. The ultrastructure of the enamel and dentin of deciduous teeth was characterized by scanning electron microscopy. The jaws and teeth were three-dimensionally reconstructed using Mimics software based on Micro-CT scanning of the deciduous teeth. Image J software was used to calculate the gray value and the mineralization density of the deciduous teeth. Hisotological structure of the tooth germ and the pulp tissue of Tibetan miniature pigs was observed using HE staining.@*RESULTS@#The deciduous teeth of Tibetan miniature pigs were composed of enamel, dentin and medullary pulp tissue. The permanent tooth germ were formed during the deciduous dentition. The enamel and dentin ultrastructure of deciduous teeth were consistent with that of human deciduous teeth. The enamel and dentin mineralization densities were 2.47±0.09 g/cm and 1.72±0.07 g/cm, respectively. The pathological structures of tooth germ and pulp tissue were similar to those of human teeth, and the pulp tissue of the deciduous teeth was in an undifferentiated state.@*CONCLUSIONS@#The deciduous teeth of Tibetan miniature pig have similar anatomy, ultrastructure and histopathological structure to human teeth and can serve as a good animal model for studying human dental tissue diseases and the mechanisms of tooth regeneration.
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Animals , Dental Enamel , Dental Pulp , Dentin , Swine , Swine, Miniature , Tibet , Tooth Germ , Tooth, DeciduousABSTRACT
Tooth development is a complex process that involves precise and time-dependent orchestration of multiple genetic, molecular, and cellular interactions. Ameloblastin (AMBN, also named "amelin" or "sheathlin") is the second most abundant enamel matrix protein known to have a key role in amelogenesis. Amelogenesis imperfecta (AI [MIM: 104500]) refers to a genetically and phenotypically heterogeneous group of conditions characterized by inherited developmental enamel defects. The hereditary dentin disorders comprise a variety of autosomal-dominant genetic symptoms characterized by abnormal dentin structure affecting either the primary or both the primary and secondary teeth. The vital role of Ambn in amelogenesis has been confirmed experimentally using mouse models. Only two cases have been reported of mutations of AMBN associated with non-syndromic human AI. However, no AMBN missense mutations have been reported to be associated with both human AI and dentin disorders. We recruited one kindred with autosomal-dominant amelogenesis imperfecta (ADAI) and dentinogenesis imperfecta/dysplasia characterized by generalized severe enamel and dentin defects. Whole exome sequencing of the proband identified a novel heterozygous C-T point mutation at nucleotide position 1069 of the AMBN gene, causing a Pro to Ser mutation at the conserved amino acid position 357 of the protein. Exfoliated third molar teeth from the affected family members were found to have enamel and dentin of lower mineral density than control teeth, with thinner and easily fractured enamel, short and thick roots, and pulp obliteration. This study demonstrates, for the first time, that an AMBN missense mutation causes non-syndromic human AI and dentin disorders.
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Adult , Female , Humans , Male , Middle Aged , Amelogenesis Imperfecta , Genetics , Cells, Cultured , China , Codon , Dentin , Congenital Abnormalities , Microsatellite Repeats , Microscopy, Electron, Scanning , Mutation, Missense , Pedigree , RNA , Transfection , Exome SequencingABSTRACT
Objective:To observe the clinical efficacy of CAD/CAM all-ceramic onlay in the restoration of molars with extensive defect after root canal therapy(RCT).Methods:260 molars with extensive defect were restored by all-ceramic onlay after RCT.The patients were followed up for 18 months.The restoration effects were assessed using USPHS criteria.Results:The success rate of CAD/CAM all-ceramic onlay was 98％.Restoration exfoliation was found in 3 cases,fractured in 2 cases.Conclusion:CAD/CAM all-ceramic onlay can be applied in restoring extensive postenor tooth-defection after RCT.
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In stomatology, root canal therapy is a commonly used and effective treatment for dental pulp diseases and periapical diseases. However, pain may occur during or after treatment and may severely affect patients. This article aimed to analyze the mechanism and cause of pain during root canal therapy, which may reduce or relieve pain.
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Humans , Pain , Periapical Diseases , Root Canal TherapyABSTRACT
Objective Comparing with traditional teaching methods of oral histopathology, to probe whether the interactive teaching system of the digital microscope can improve the teaching effi-ciency of experiment of oral histopathology courses. Methods The subjects were the 2010 grade students (40 students) and the 2011 grade students (38 students) majoring in stomatology of South Medical University, and they were evenly divided into 2 groups at random. In the first part of the ex-periment of Grade 2010, the teaching of traditional optical microscope was used in a group of experi-mental courses, and interactive teaching with digital microscope was used in the other group. In the second part of the experiment the two groups swapped the teaching method. While in the whole exper-iment of Grade 2011, traditional optical microscopes were adopted in one group, and in contrast, the interactive teaching system of the digital microscope was adopted in the other group. The P values of the 5 indexes were less than 0.05. After the courses, the 2010 grade students received the questionnaire survey and the 2011 grade students received the quiz about the experimental course, and then the evaluation results of the two groups were compared for t inspection, using SPSS software t test. Result The questionnaire results of Grade 2010 showed that the scores of digital microscope interactive group were higher than those of traditional teaching group in satisfaction with teaching , teacher-student interaction, classroom atmosphere active degree, learning interest, and the understanding of the teach-ing content. The experiment course content test results of Grade 2011 showed that the digital interactive group students averaged 46.26, while the average score of the traditional teaching group was 42.78%. The difference between the two groups had statistical significance, P=0.001. Conclusion Compared with the traditional teaching methods, the interactive teaching system of the digital microscope can enhance the academic grades, improve the teaching efficiency of experiment of oral histopathology courses, and elevate the teaching quality.
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Objective:To evaluate the effects of periodontal flap surgery with the aid of microscope in the treatment of patients with chronic periodontitis(CP).Methods:30 patients with CP included in the study were randomly divided into 2 groups.Patients in the experiment group received periodontal flap surgery with the aid of microscope,while those in the control group received the routine flap surgery.The VAS pain scores were compared 1 ,3 and 7 days after surgery.The periodontal parameters were compared 3 and 6 months after surgery between 2 groups.Results:The VAS pain score in the experiment group was significantly lower than that in the control group 1 and 3 days (P =0.01 7 and 0.004)after surgery;the periodontal probing depth in the experiment group was significantly lower than that in the control group 3 and 6 months (P =0.01 0 and 0.047)after surgery.Conclusion:The periodontal probing depth,gin-gival recession and clinical attachment level can be improved and the pain can be reduced in the treatment of CP patients with the aid of microscope in the periodontal flap surgery.
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Objective:To investigate the effect of modified plateletrich plasma(mPRP)on the osteogenic differentiation of stemcells from human exfoliated deciduous teeth(SHED).Methods:mPRP at 1%,2%,5%,10% and FBS at 10% were added to thecultured SHED of passage 4,respectively.The influence of mPRP on alkaline phosphatase(ALP)activity was evaluated using ALPkit.RUNX2 and osteocalcin mRNA expression in the treated cells were examined by realtime PCR.Results:mPRP enhanced ALPactivity in the SHED,and the effect of mPRP was more obvious at 2%.Treatment of the cells with 2% mPRP upregulated the mRNAexpressions of RUNX2 and osteocalcin.Conclusion:mPRP can promote the osteogenic differentiation of SHED.
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<p><b>OBJECTIVE</b>To examine the role of lactoferrin (LF) on Toll like receptor 4 (TLR4) stimulated by lipopolysaccharide (LPS) in human periodontal ligament cells (hPDLCs).</p><p><b>METHODS</b>Primary hPDLCs were cultured by tissue block enzymolytic method. Cells obtained from four passages were identified and used in this experiment. Cells without stimulation served as the controls and cells treated with LPS (0.1 microg x mL(-1)) comprised the LPS group. The LPS + LF group was pretreated with LPS (0.1 microg x mL(-1)) for 2 h, and then treated with LF (10 microg x mL(-1)). Four hours after LF stimulation, the mRNA expression levels of TLR4 were examined by real-time quantitative polymerase chain reaction (RT-PCR). The protein expression of TLR4 was observed by cell immunofluorescence staining after LF stimulation of 24 hours.</p><p><b>RESULTS</b>TLR4 mRNA expression in the LPS + LF group was significantly more decreased than that in the LPS group (P < 0.05), but exhibited no difference with that in the control group (P > 0.05). Cell immunofluorescence staining showed that the protein expression of TLR4 in the LPS + LF group was significantly more decreased than that in the LPS group (P < 0.05), but exhibited no difference with that in the control group (P > 0.05).</p><p><b>CONCLUSION</b>LF can decrease the expression of TLR4 stimulated by LPS in hPDLCs, thus presenting potential application for controlling the TLR4 immune pathway of periodontitis.</p>
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Humans , Down-Regulation , Lactoferrin , Lipopolysaccharides , Periodontal Ligament , Periodontitis , Toll-Like Receptor 4ABSTRACT
Objective To compare the effect of different nickel-titanium rotary files on fracture resistance of teeth by observing status of dentinal microcracks after root canal preparation with.Methods 6 5 mandibular anterior teeth with single oval canal were randomly divided into three experimental groups (n=20)and a control group (n=5),SAF、ProTaper Universal and ProTaper Next system were used to prepare root canal in experimental groups,while the control group were left unprepared.Roots were sectioned from 3,6,9 mm to the apex,its status of dentinal microcracks was evaluated under a stereomicroscope.Results Root fracture inci-dence rate of group ProTaper Universal was significantly higher than that of group SAF and group ProTaper Next (P0.05).Conclusion Roots with oval shaped canal prepared with SAF and ProTaper Next produce less dentinal microc-racks,which decrease risk of vertical root fracture.
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BACKGROUND:Previous experiments have shown that modified platelet-rich plasma activated by liquid nitrogen freezing and thawing can promote the proliferation of human bone marrow mesenchymal stem cells and dental pulp stem cells in a concentration-dependent manner. OBJECTIVE:To investigate the effect of modified platelet-rich plasma at different concentrations on the proliferation of dental pulp stem cells from human exfoliated deciduous teeth. METHODS:Platelets were selected and harvested by automatic blood cellanalyzer, and then activated by liquid nitrogen freezing and thawing.α-MEM served as basal medium. Different concentrations of modified platelet-rich plasma (2%, 5%, 10%, 20%) or 10%fetal bovine serum were added, respectively. The difference in cellproliferation was observed. RESULTS AND CONCLUSION:Modified platelet-rich plasma at different concentrations could promote the proliferation of dental pulp stem cells from deciduous teeth. The effects of 2%modified platelet-rich plasma and 10%fetal bovine serum on promoting the proliferation of dental pulp stem cells from deciduous teeth were similar. These results indicated that 2%modified platelet-rich plasma could promote the proliferation of dental pulp stem cells from deciduous teeth, and substitute for fetal bovine serum in the amplification of dental pulp stem cells from deciduous teeth in vitro.
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To investigate the ultrastructural changes of dentin irradiated with 980-nm diode laser under different parameters and to observe the morphological alterations of odontoblasts and pulp tissue to determine the safety parameters of 980-nm diode laser in the treatment of dentin hypersensitivity [DH]. Twenty extracted human third molars were selected to prepare dentin discs. Each dentin disc was divided into four areas and was irradiated by 980-nm diode laser under different parameters: Group A: control group, 0 J/cm[2]; Group B: 2 W/CW [continuous mode], 166 J/cm[2]; Group C: 3W/CW, 250 J/cm[2]; and Group D: 4W/CW, 333 J/cm[2]. Ten additional extracted human third molars were selected to prepare dentin discs. Each dentin disc was divided into two areas and was irradiated by 980-nm diode laser: Group E: control group, 0 J/cm[2]; and Group F: 2.0 W/CW, 166 J/cm[2]. The morphological alterations of the dentin surfaces and odontoblasts were examined with scanning electron microscopy [SEM], and the morphological alterations of the dental pulp tissue irradiated by laser were observed with an upright microscope. The study demonstrated that dentinal tubules can be entirely blocked after irradiation by 980-nm diode laser, regardless of the parameter setting. Diode laser with settings of 2.0 W and 980-nm sealed exposed dentin tubules effectively, and no significant morphological alterations of the pulp and odontoblasts were observed after irradiation. Irradiation with 980-nm diode laser could be effective for routine clinical treatment of DH, and 2.0W/CW [166 J/cm[2]] was a suitable energy parameter due to its rapid sealing of the exposed dentin tubules and its safety to the odontoblasts and pulp tissue
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Humans , Lasers, Semiconductor , Odontoblasts , Microscopy, Electron, Scanning , Dental Pulp , LasersABSTRACT
<p><b>OBJECTIVE</b>To evaluate the effects of sandblasting and different orthodontic adhesives on shear bond strength between zirconia and enamel.</p><p><b>METHODS</b>Zirconia ceramic samples were designed and manufactured for 40 extracted human maxillary first premolars with CAD/CAM system. The samples were randomized into 4 groups for surface treatment with sandblasting and non-treated with adhesives of 3M Transbond XT or Jingjin dental enamel bonding resin. After 24 h of bonded fixation, the shear bond strengths were measured by universal mechanical testing machine and analyzed with factorial variance analysis.</p><p><b>RESULTS</b>The shear bond strength was significantly higher in sandblasting group than in untreated group (P<0.05) and comparable between the two groups with the adhesives of Transbond XT and dental enamel bonding resin (P>0.05).</p><p><b>CONCLUSION</b>The shear bond strength between zirconia and enamel is sufficient after sandblasting regardless of the application of either adhesive.</p>
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Adolescent , Adult , Humans , Young Adult , Adhesives , Computer-Aided Design , Dental Enamel , In Vitro Techniques , Molar , Resins, Synthetic , Shear Strength , Surface Properties , ZirconiumABSTRACT
BACKGROUND:Previous studies have confirmed the presence of bis-(3'-5')-cyclic dimeric guanosine monophosphate signaling pathway in Streptococcus mutans, which construct the streptococcus mutans gcp gene knockout strains. OBJECTIVE:To compare the gene expression differences between Streptococcus mutans wild strains and gcp mutant strains, and to screen the biofilm-related genes from them for the fol ow-up study. METHODS:The total RNA of two kinds of strains were extracted and stained with cy3 and cy5 respectively after reverse transcription. The gene chip was scanned after hybridization and the differential gene were obtained through the data analysis. The different expression genes were verified by real-time PCR. RESULTS AND CONCLUSION:Differential genes were mainly relative about glucose metabolism and biofilm formation. We selected two genes for real-time PCR verification. The PCR results were consistent with the microarray results. After Streptococcus mutans gcp gene knockout, the gene expressions of gcp mutant strains were upregulated and the gene expressions of phosphotransferase system were downregulated, this result suggested that two different genes were related with the c-di-GMP signal pathway downstream.
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<p><b>OBJECTIVE</b>To investigate the effect of exogenous c-di-GMP in preventing dental caries formation in SD rats.</p><p><b>METHODS</b>Twenty-day-old SD rats with dental caries induced by S. Mutans infection were randomly divided into 3 groups for treatment with dental application of exogenous c-di-GMP, NaF solution or 0.9% NaCl, and changes in the bacterial number and scores of dental caries following the treatments were recorded.</p><p><b>RESULTS</b>Compared with 0.9% NaCl treatment, exogenous c-di-GMP treatment significantly lowered the scores of dental caries on the occlusal surface and smooth surface (P<0.05) but produced no obvious effect on the number of bacterial plagues (P>0.05).</p><p><b>CONCLUSION</b>Exogenous c-di-GMP can be a novel agent for prevention and treatment of tooth decay.</p>
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Animals , Female , Rats , Cyclic GMP , Therapeutic Uses , Dental Caries , Microbiology , Disease Models, Animal , Streptococcus mutansABSTRACT
ObjectiveTo survey and analyze the changes of dental medical students' concerns before and after their internship in order to provide practical evidences for intern orientation and junior students education.MethodsAnonymous questionnaires were designed with single choice and multiple-choices and were accomplished by 175 dental medical students of different grades to investigate their' concerns before and after the clinical internship and choices for future employment.Results 47％ freshmen,43％ junior,45％ graduates were willing to work in dental restoration field,30％sophomore and 39％ senior were willing to work in orthodontics field.Before the internship,the most concem of 97％ students was the teaching quality of the practice hospital; 67％ students worried that patients may unsatisfy with the treatment.After the internship,the quality of the practice hospital was considered most important by 79％ students; 51％ students worried that internship may influence the postgraduate entrance exam.ConclusionTeachers should strengthen their self-cultivation and cope with the key concerns before the practice based on the investigation and survey after the practice.Meanwhile teacher should provide employment guidance for students based on students' interests and practice skill ability,encourage them to broaden their horizon and pay attention to the long-term interests in an aim to pave the way for future employment.
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Objectives:To study the preparation techniques of gelatin microspheres encapsulated with sodium fluoride and evaluate the anticaries functions in dental plaque model in vitro. Methods:Fluoride gelatin microspheres were prepared by emulsion polymerisation method. The encapsulation rate and drug contents were tested by ISE. In vitro inhibition of demineralization were also examined. Results:The mean size of fluoride GMS was (16.81?8.77)?m.The encapsulation rate was 76.73%.The drug content was 5.61%.The release profile in vitro showed sustained effects. Fluoride GMS can prevent demineralization more efficiently. Conclusions:Fluoride gelatin microspheres may be an promising topical fluoride release system.
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Objective:To establish a model for the study of tooth initiation and early development by in vitro culture of mouse mandibular arch . Methods:42 mandibular arches of 11dpc fatal mouse were dissected and cultured in Trowell organ culture system for 11 days.Regular histologic observation was performed to observe the initiation and development of tooth.Results: Mandibular arches grew well in Trowell culture system.The initiation and early development of tooth was found.The explants maintained to cap stage.On day 11,necrosis of the cultured mandibular arches was observed and the culture was ended. Conclusion:In vitro cultured mandibular arch can be used as a model for the study of tooth initiation and early development.
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砄bjective: To investigate the effect of calcitonin gene related peptide(CGRP) on calcification function of human dental pulp cells(HDPCs) in vitro . Methods: HDPCs cells were exposed to calcitonin gene related peptide at the dosages(mol/L) of 10 -12 , 10 -10 and 10 -8 for 3,6,9, 12 and 15 days respectively. Cell growth was studied by cell counting , alkaline phosphatase(AL) by a AL kit, osteocalin by immunoradiological tecnique and type I collagen mRNA expression by RT PCR. Results: CGRP did not show any effect on the growth of HDPCs, but it increased the expression of AL, osteocalin and type I collagen mRNA in HDPCs in a dose dependent and not time dependent manner. Conclusion: CGRP plays an important role in promoting differentiation and calcification function of HDPCs
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Objective:To investigate the expression of dental matrix protein 1(DMP1)in carious human permanent teeth and its possible role during the reparative process after pulp injury.Methods:10 of noncarious third molars (NC),10 of shallow carious (SC),10 of intermediate carious (IC) and 10 of deep carious (DC) were prepared for the detection of DMP1 in odontoblasts by immunohistochemical staining. DMP1 expression in odontoblasts was analyzed by image analysis system and expressed as integral optical density (IOD).Results:DMP1 was majorly detected in cytoplasms and processes of odontoblasts and odontoblast-like cells.The IOD values in the groups of NC,SC,IC and DC were 0.265?0.018,0.309?0.021,0.678?0.031 * and 0.691? 0.033 * respectively;that in the reparative dentin in DC group was 0.856?0.045 ** ( *vs NC P
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Objective: To observe the clinical disinfection effect of root canal with non-filling medication. Methods: 36 patients who required root canal therapy(RCT) for apical periodontitis (acute or chronic) or pulp necrosis were involved in the study.RCT was completed after two visits in both groups. Non-filling medication was used as disinfection in 18 teeth of 18 patients (experimental group) while FC in another 18 teeth of 18 patients (control group) randomly at first visit.One week later,root canal was regularly filled to complete RCT.From each case, bacteria specimens were collected and identified before sealing and filling. Results: Bacteria were detected in every specimen in both groups before sealing,which were mixture of aerobes and anaerobes.One week later,only one strain was detected in one specimen of each group. Conclusion: Non-filling medication can be used as an effective disinfection to sterilize root canal.