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Adsorption dynamics study on interactions of pigments and human whole saliva.

West China Journal of Stomatology.2012;30(3):239-242.

OBJECTIVEIn situ, real timely and dynamically monitoring the processes of theaflavin (TF), curcumin (Cur) and cyanidin (Cy) binding to human whole saliva (WS) surface has been investigated by surface plasmon resonance (SPR) technique at the molecular level.

METHODSThe affinity between pigments and WS, association rate constant (k(a)), dissociation rate constant (k(d)), association equilibrium constant (K(A)) and dissociation equilibrium constant (K(D)) of pigments binding on WS surface had been determined by SPR and the Langmuir model as well as the Freundlich model. The data were analyzed by one-way ANOVA and SNK-q test.

RESULTSThere were significant differences among TF, Cur and Cy in k(a), k(d), K(A) and K(D) (P<0.05). Our results showed that the adsorption isotherm of pigments on WS surface could be better described by the Freundlich model than the Langmuir model. The pigments adsorption on WS surface was dominant by specific interactions, such as hydrogen bonding. The affinity of pigments to WS were TF> Cur>Cy (P<0.05), as evidenced by the rate constants and equilibrium constants.

CONCLUSIONCompared with Cur and Cy, TF shows much higher adsorption capacity on WS surface, suggesting the importance of the hydroxyl group in pigment/protein interactions.

Adsorption ; Anthocyanins ; Biflavonoids ; Catechin ; Curcumin ; Humans ; Saliva ; Surface Plasmon Resonance

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Indian Hedgehog signaling is involved in the stretch induced proliferation of osteoblast.

Lei HAN ; Xiaoling ZHANG ; Guohua TANG

West China Journal of Stomatology.2012;30(3):234-238.

OBJECTIVETo observe the role of the Hedgehog (Hh) genes in the proliferation of osteoblasts upon mechanical tensile strains.

METHODSPrimary osteoblasts harvested from newborn rat calvarial bone were subjected to 3% and 6% elongation of tensile stretches using Flexcell 4000 strain unit. The cultures were also treated with either recombinant N-terminals Sonic Hedgehog (N-Shh) or cyclopamine (cy), a Hh inhibitor or gadolinium (GdCl3), an inhibitor of stretch-activated channels. The proliferation of osteoblasts was quantified by cell counting, methyl thiazolyl tetrazolium (MTT) and cell cycle detection via flow cytometry. Statistical analysis was performed using SAS 8.0 software package.

RESULTSThe tensile strain, especially under 6% elongation, promoted osteoblast proliferation. Stretching force could also promote the proliferation even when the cells were treated with cy, but this effect was suppressed by GdCl3.

CONCLUSIONThe induced proliferation of osteoblasts by mechanical stretched is mediated at least in part by Indian Hedgehog (Ihh) signaling.

Animals ; Cell Proliferation ; Hedgehog Proteins ; Osteoblasts ; Rats ; Signal Transduction ; Veratrum Alkaloids

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A study of repairing mandibular defect using tissue engineering bone with bone marrow stem cells cell sheets in dog.

Chao YAO ; Lingxue BU ; Ke WANG ; Ningyi LI ; Lingling WANG ; Yueyuan YU

West China Journal of Stomatology.2012;30(3):229-242.

OBJECTIVETo reconstruct mandibular defect using tissue engineering bone with bone marrow stem cells (BMSCs) cell sheets and investigate the effect of cell sheets on osteogenesis.

METHODSBMSCs were isolated with the method of density gradient centrifugation from canine and cultured. BMSCs were induced to differentiate to osteoblasts. BMSCs induced were fabricated to BMSCs cell sheets. The poly (lactic-co-glycolic acid) (PLGA) wrapped with cell sheets were implanted into the mandibular defect in the left side (experimental side). PLGA wrapped without cell sheets were implanted into the right side (control side) of mandibles. 16 dogs were evenly divided into 4 groups, and one group of them was executed in 4, 8, 12, 16 weeks for gross investigation and histological observation.

RESULTSThe osteogenesis of experimental side was better than that of control side. 16 weeks after implantation, most areas of the mandibular defect were replaced by fresh bone tissue. Compact bone similar to normal bone tissue formed in the lingual defect of mandible and had bony union with the bone stump. The optical density of the fresh bone in the experimental side was higher than that of the control side, there was a significant difference between the two methods (P<0.05). Plenty of lamellar bones formed in experimental side and Haversian system, as well as red marrow, were observed.

CONCLUSIONTissue engineering bone with the structure of lamellar bones can be formed by the technology of BMSCs cell sheets.

Animals ; Bone Marrow Cells ; Bone and Bones ; Dogs ; Lactic Acid ; Mandible ; Osteoblasts ; Osteogenesis ; Polyesters ; Polyglycolic Acid ; Polymers ; Tissue Engineering

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Confusing anchorage.

Tianmin XU

West China Journal of Stomatology.2012;30(3):225-228.

Just like other subjects in medicine, orthodontics also uses some vague concepts to describe what are difficult to measure quantitatively. Anchorage control is one of them. With the development of evidence-based medicine, orthodontists pay more and more attention to the accuracy of the clinical evidence. The empirical description of anchorage control is showing inadequacy in modern orthodontics. This essay, based on author's recent series of studies on anchorage control, points out the inaccuracy of maximum anchorage concept, commonly neglected points in quantitative measurement of anchorage loss and the solutions. It also discusses the limitation of maximum anchorage control.
Bone Screws ; Humans ; Orthodontic Anchorage Procedures ; Orthodontics

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A gate spring which can torque an individual tooth with high efficiency.

Yu LI ; Yu GUAN ; Lanlan PAN ; Zhihe ZHAO

West China Journal of Stomatology.2012;30(2):222-223.

It is to address torquing an individual tooth using a gate spring. The gate spring is made of a rectangular stainless steal wire, in the shape of a gate, which is incorporated to the archwire by spot welding. Torque is generated by the combined effects of the gate spring and the archwire. After 2-3 months, the gate spring can obviously torque individual tooth.
Orthodontic Appliance Design ; Orthodontic Brackets ; Orthodontic Wires ; Tooth ; Tooth Movement Techniques ; Torque

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Allergy caused by sodium fluoride glycerin: a case report.

Jihong MA

West China Journal of Stomatology.2012;30(2):221-223.

In recent years, though more and more ulcerations of oral mucosa caused by allergy to drug occurred clinically, allergy to sodium fluoride glycerin is extremely rare. A case of allergy to sodium fluoride glycerin occurred in Qianfoshan Campus Hospital of Shandong University. After treatment by sodium fluoride glycerin, there was mucosal edema, a large number of red miliary granules in buccal and palatal mucosa. After 3 hours, there were swallowing difficulties, but no breathing difficulties. Next day large ulcers of oral mucosa developed. The patient was cured 7 days after treatment. Fluoride-sensitive test result was positive.
Fluorides ; Glycerol ; Humans ; Hypersensitivity ; Male ; Mouth Mucosa ; Phosphates ; Sodium Fluoride

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Mechanical properties of thermodynamic nickel-titanium archwires in a simulated oral environment in vitro.

Xusheng FAN ; Zhihua LI ; Hui SHI ; Xiang LIU

West China Journal of Stomatology.2012;30(2):217-220.

OBJECTIVEThis study was to investigate the mechanical properties of thermodynamic nickel-titanium (NiTi) archwires of different brands under controlled temperature and in artificial saliva to provide some reference for its clinical application.

METHODSUsing a modified partial dental arch bending system, four types of thermodynamic NiTi archwires were tested under controlled temperature (25, 33, 37, 60 degrees C) and in artificial saliva. An Instron Universal Testing Machine was used to apply 3 mm deflections of archwires in the lateral incisor area. The load-deflection curves were determined from the passive position to deflections of 3 mm. The following variables from unloading curves were calculated: Stiffness between 2.5 mm UDP (unloading deflection point) to 0.5 mm UDP after unloading. Any statistically significant differences in these variables for the different brands, temperature and moments levels were analyzed using one-way analysis of variance.

RESULTSUnloading values of four types thermodynamic nickel-titanium archwires increased with controlled temperature rising. The unloading stiffness of the same brand archwires were approximate at 25, 33, 37 degrees C, while their unloading stiffness increased obviously at 60 degrees C.

CONCLUSIONDifferent brands thermodynamic NiTi archwires demonstrated different mechanical behaviours, but all of them exhibited super elasticity and practical shape memory effect. The four thermodynamic NiTi archwires displayed temperature sensitivity at the four test temperatures.

Dental Alloys ; Dental Stress Analysis ; Elasticity ; Humans ; In Vitro Techniques ; Materials Testing ; Nickel ; Orthodontic Wires ; Temperature ; Titanium

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Caries status of primary and permanent teeth among 6-year-old children in Sichuan province and their correlation.

Jianzhong LIU ; Xue LI ; Deyu HU ; Ximu ZHANG ; Songlin HE

West China Journal of Stomatology.2012;30(2):214-220.

OBJECTIVETo investigate caries status of primary and permanent teeth among 6-year-old children in Sichuan Province and correlation between caries of deciduous molars and first permanent molars.

METHODSReferenced to the sampling programme of the third national epidemiological survey of oral health status, a total of 714 children aged 6 were randomly sampled in clusters including 3 urban sampling spots and 3 rural sampling spots, the correlation between caries of deciduous molars and first permanent molars was explored.

RESULTSThe prevalence rate of deciduous tooth caries of 6-year-old children in Sichuan province was 74.37%, the mean number of dmft of 6-year-old was 3.94 +/- 3.93, the filling rate was only 4.96%. The prevalence rate and mean dmft of deciduous tooth caries showed no significant difference between different area and gender (P>0.05), however, the children came from city showed significant higher filling rate than those from countryside (P<0.05). The first permanent molars erupted have 2.98% in caries, the filling rate was 7.69%. Caries of deciduous molars was the first permanent molars caries risk factors among 6-year-old children in Sichuan province [P=0.001, r=0.175, OR=5.756, 95%CI (1.733, 19.121)]. There was weak correlation between caries of deciduous molars and first permanent molars (P<0.001, r=0.194).

CONCLUSIONCaries status of primary among 6-year-old children in Sichuan Province are serious. Caries experience of deciduous molars may play an important role in predicting the first permanent molars caries in clinic and prevention.

Child ; DMF Index ; Dental Caries ; Female ; Humans ; Male ; Molar ; Prevalence ; Risk Factors ; Tooth, Deciduous

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Biocompatibility of porous calcium phosphate ceramic nanocomposite.

Kefu ZHANG ; Shu ZHANG ; Zhiqiang LUO ; Jing WANG ; Tao WANG ; Guomin OU ; Hu WANG

West China Journal of Stomatology.2012;30(2):209-213.

OBJECTIVETo study the biocompatibility of porous calcium phosphate ceramics nanocomposite.

METHODSThe biocompatibility was evaluated via experiments including the hemolysis test, hemopexis test, acute systemic toxicity test, pyrogen test, and intramuscular implant test, in which biphasic calcium phosphate nanocomposite (NanoBCP) presented as leaching solution, suspension or blocks of 5 mmx5 mmxl mm. Animals including New Zealand Rabbits, Kunming mice, SD rats were selected as the host.

RESULTSThe hemolysis of NanoBCP was 1.1% (<5%). Four coagulation index levels were within the normal range. In pyrogen test, the temperature of each experimental rat increased by 0.35, 0.40, 0.28 degrees C (<0.60 degrees C, in accordance with the pyrogen-free criterion for biomedical materials). No consequent death, dyspnoea, organ dysfunction, severe peritoneal irritation or ptosis was observed in acute systemic toxic test. Newly-formed fibrous tissue could be found after the implantation.

CONCLUSIONThe material possesses outstanding biocompatibility and degradability with no toxicity or irritation, contains no pyrogen, as well as better degradation properties than biphasic calcium phosphate.

Animals ; Biocompatible Materials ; Calcium Phosphates ; Ceramics ; Hydroxyapatites ; Mice ; Nanocomposites ; Prostheses and Implants ; Rabbits ; Rats ; Rats, Sprague-Dawley

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The observation of surface morphology of enamal and temperature of dental pulp cavity in vitro after irradiated by Er:YAG laser.

Lijun YE ; Luchuan LIU ; Manjing DENG ; Na LIU ; Xi WU ; Zhengmou DONG

West China Journal of Stomatology.2012;30(2):206-208.

OBJECTIVETo observe the changes of surface morphology and temperature of dental pulp cavity in vitro after irradiated by Er:YAG laser with different energy and irradiation time.

METHODSAll of the 96 samples from 24 teeth in vitro were collected from dental clinical departments then divided into two groups (group A and group B) randomly. We chose the energy of 20 Hz, and 1, 2, 3, 4, 5, 6 W to treat the samples in group A and group B and the irradiation time was 10s or 20s. We recorded the temperature changes of dental pulp cavity by digital thermometer and observe the morphology of tooth enamel by scanning electron microscope (SEM).

RESULTSWith the extension of irradiation time and increasing of energy, the temperatures of dental pulp cavity were significantly increased after the treatment of Er: YAG laser. The two groups of tooth enamel surface morphology were changed after irradiated by Er: YAG laser with different energy and irradiation time. However, there was no melting and carbonation on the surface of tooth enamel after the treatment of Er:YAG laser in two groups.

CONCLUSIONThe temperatures of dental pulp cavity were increased after irradiated by increasing laser energy density fom 1 W to 6 W. No melting or carbonized phenomenon was found in enamel within the energy of 1 W to 6 W. All the data would provide evidences for clinical treatment of cavity.

Dental Caries ; Dental Enamel ; Dental Pulp Cavity ; Humans ; In Vitro Techniques ; Lasers ; Lasers, Solid-State ; Microscopy, Electron, Scanning ; Temperature

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