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ABSTRACT: The study established an animal model of autologous tooth transplantation in dogs and aimed to explore the effects of orthodontic loading time and duration on the periodontal repair in autologous tooth transplantation.
12 Beagle dogs were selected and grouped randomly in this research. Four first premolar teeth in every dog were carried on autologous transplant operation. These teeth were exerted the orthodontic force after the operation in 2, 4, 8 and 12 weeks respectively. The loading duration was 1, 2 and 4 weeks respectively. We examined the dental and periodontal tissue samples in first premolar teeth by histological study, measured root absorption rate and analyzed reconstruction condition of periodontal tissue with statistical methods.
Root absorption rates of the experimental group which was exerted the orthodontic force were lower than those of the control group. The difference between two groups had statistical significance (P < 0.05). Root absorption rates in different levels of orthodontic loading time (X) and the duration (Y) had no statistical significance (P > 0.05), but these two factors had interaction effect (P(X x Y) < 0.05).
Orthodontic force contributes to the improvement of root absorption and reconstruction of periodontal tissue in transplant teeth. The orthodontic loading time and the duration have no obvious effect on root absorption rate of transplant teeth. When X is two weeks and Y is four weeks, it is most beneficial for the reconstruction effect of periodontal tissues in transplant teeth.
Hua xi kou qiang yi xue za zhi = Huaxi kouqiang yixue zazhi = West China journal of stomatology 06/2011; 29(3):237-41.
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ABSTRACT: The aim of this investigation was to study the osteogenesis activation following asymmetric inter-maxillary elastic on the subchondral bone of adult SD rats.
Twenty SD ten-week old rats were used in this study (eight rats loading 0.39 N elastic force, another eight rats loading 1.18 N elastic force, the other four rats without loading as control group). The extra-joint device was fixed on the right side by surgery. Tetracycline, calcein and xylenol orange were intraperitoneally injected on one day before surgery, one day before device removal and one day before sacrifice. Masson trichrome staining and in vivo fluorescence technique were used to detect the osteogenesis.
The results of bone collagen maturation and velocity of osteogenesis were different from the control group after force loading. Bone collagen showed better maturity in force-loading side and light force induced more active osteogenesis.
The results suggest that even in the adult SD individuals, the subchondral bone still shows remodeling ability to adapt the various mechanical environments. Stress increases the maturity of bone collagen while rotation inhibits maturity. Mechanic force promotes the osteogenesis, especially the light force.
Shanghai kou qiang yi xue = Shanghai journal of stomatology 10/2010; 19(5):499-502.
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ABSTRACT: The aim of this survey was to compare Chinese natives and foreign inhabitants in Chengdu, China, with respect to: (1) attitudes towards dental appearance, (2) subjective orthodontic treatment need, and (3) the main factors influencing orthodontic treatment need.
A total of 522 subjects, including 227 foreign inhabitants and 295 Chinese natives in Chengdu participated in the survey. A simple random sampling method was adopted and a face-to-face interview was conducted at some public sites using a questionnaire. Data was entered by two persons synchronously using Epidata 3.0, and SPSS 13.0 was used to analyze these data.
89.0% of foreign inhabitants were satisfied with their teeth compared to only 46.8% of Chinese natives. Females were more dissatisfied with their teeth than males. Chinese natives put improving appearance as the top priority (55.9%) for seeking orthodontic treatment; however, in foreign inhabitants, the main reason for seeking treatment was to improve masticatory function (44.1%), followed by "to be pretty" (35.2%). The importance of well-aligned teeth and self-perception of psychosocial impact of malocclusion were the same two main factors influencing subjective orthodontic treatment need (P < 0.05) in foreign inhabitants and Chinese natives. Subjective orthodontic treatment need between the two target groups was significantly different (P < 0.05).
(1) It was very common that Chinese natives were dissatisfied with their dental appearance, and their subjective orthodontic treatment needs were high. (2) There were some differences in orthodontic treatment motives between the two target groups. (3) There were differences in subjective orthodontic treatment needs between foreign inhabitants and Chinese natives. However, the prominent influential factors were almost the same. There may be benefit to understanding subjective orthodontic needs of different races.
International Journal of Oral Science 09/2010; 2(3):149-57. · 1.41 Impact Factor
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ABSTRACT: The objectives of this study were to investigate the early response to mechanical stress in neonatal rat mandibular chondrocytes by proteomic analysis. To evaluate its molecular mechanism, chondrocytes were isolated and cultured in vitro, then loaded mechanical stress by four-point bending system on different patterns. Morphological observation, flow cytometric analysis, and MTT assays indicated that 4,000 microstrain loading for 60 min was an appropriate mechanical stimulus for the following proteome analysis, which produced a transient but obvious inhibitory effect on the cell cycle. Therefore, we took a proteomic approach to identify significantly differential expression proteins in chondrocytes under this mechanical stress. Using 2-DE and MALDI-TOF, we identified seven differentially expressed proteins including the MAPK pathway inhibitor RKIP, cytoskeleton proteins, actin and vimentin, and other selected proteins. Some differentially expressed proteins were validated by both Western blot analysis and fluorescent staining of cytoskeleton at different loading times. The vimentin and RKIP responsive expression were also proven in vivo in oral orthopedic treatment rats, which was in line with the result in vitro. The histological changes in cartilage also showed the inhibition effect. Furthermore, the expressional level of phosphorylated ERK was increased, which demonstrates the changes in MAPK activity. Taken together, these data indicate that mechanical stress resulted in vimentin expression changes first and then led to the subsequent changes in actin expression, MAPK pathway regulated by RKIP and heat shock protein GRP75. All those changes contributed to the cytoskeleton remolding and cell cycle inhibition, finally led to condylar remodeling.
Journal of Cellular Physiology 06/2010; 223(3):610-22. · 3.87 Impact Factor
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ABSTRACT: HX straight-wire appliance (HX-SWA) is designed and adjusted by doctors of Orthodontic Department, West China College of Stomatology, Sichuan University. It is a set of appliance that is constructed according to normal occlusion features of the Chinese people, including the prescription of tip, torque, in/out, counter-tip, counter-rotation and overcorrection in brackets and buccal tubes. Some ingredients of the appliance are different from that of the most popular Roth straight-wire appliance in the world wide. Over a period of the last 10 years, doctors in our hospital kept on summarizing treatment experience with HX-SWA, which will help more doctors promote practice and results in orthodontic clinic.
Hua xi kou qiang yi xue za zhi = Huaxi kouqiang yixue zazhi = West China journal of stomatology 06/2010; 28(3):229-33.
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ABSTRACT: A family with Angle's Class ii malocclusion was identified in West China Stomatological Hospital of Sichuan University. The proband was a 22-year-old woman with Angle's Class II Division 2 malocclusion with congenitally missing teeth. A total of 15 members of the 3 generations in the family were investigated. There were 7 members (3 males, 4 females) with Angle's Class II malocclusion in the family. The results provide the primary basis for further study to localize the virulence gene.
Hua xi kou qiang yi xue za zhi = Huaxi kouqiang yixue zazhi = West China journal of stomatology 04/2010; 28(2):219-20.
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ABSTRACT: The aim of this investigation was to study the expression of collagen type II in the cartilage of mandibular condyle following asymmetric inter-maxillary traction.
Two hundred and twenty SD rats were used in this study (one hundred and four rats loading 0.39 N elastic force, another one hundred and four rats loading 1.18 N elastic force, while twelve rats for control). The extra-joint device was fixed on the right side by surgery. Half of the experimental group was killed at 3, 7, 14, 28 days. The devices were removed at the 28th day in the rest rats, and the rats were sacrificed at 3, 7, 14, 28 days after removing the device. The type II collagen expression levels of all the joints were measured using immunohistochemical techniques.
The positive expression of the type II collagen was mainly observed in the cytoplasm of chondrocyte, especially in maturative and hypertrophic layer. The expression intensity was different in different stages and different sides. Both of the two experimental groups showed the same tendency, while the changes in the light force group were more obviously than the heavy force group. In the right side (force-loading side), the type II collagen expression decreased at the early force-loading period. After the device was removed, the expressions increased immediately but then reach the lowest level. The expression almost recovered to normal level at the end of experiment. In the left side (none force-loading side), the expression remained increasing after force-loading and reached the peak at the 14th day.
These results suggest that even in the adult individuals, the chondrocyte showed reaction to the mechanical force by altering type II collagen expression patterns and it may be the cause of the cartilage remolding after asymmetric inter-maxillary traction. A forward elastic force showed a depressant effect in matrix synthesis, and heavy force had stronger effect. But the rotation of condyle accelerated the matrix synthesis.
Hua xi kou qiang yi xue za zhi = Huaxi kouqiang yixue zazhi = West China journal of stomatology 10/2009; 27(5):548-52.
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ABSTRACT: There are three kinds of mechanisms regulating the growth and development of skeletal tissue: Bone growth, bone modeling and bone remodeling. However, in the current orthodontics literature, there continues to be substantial confusion regarding the usage of the term "bone remodeling". This article reviews the historical causes for this semantics problem and explains the difference between bone modeling and remodeling, as well as the detailed skeletal regulating mechanisms in the growth and development of cranial-facial bones and orthodontic treatment. At last, this article suggests Chinese orthodontists use the terms "bone modeling" and "bone remodeling" more precisely to avoid scientific confusion and barriers to scientific exchange with other biomedical disciplines.
Hua xi kou qiang yi xue za zhi = Huaxi kouqiang yixue zazhi = West China journal of stomatology 10/2009; 27(5):577-81.
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ABSTRACT: The long distance displacement of canine is a rare phenomenon in orthodontic clinic. Its related clinical epidemiology, etiology, diagnosis and treatment methods are briefly summarized, and a case of mandibular canine displaced in chin is reported.
Hua xi kou qiang yi xue za zhi = Huaxi kouqiang yixue zazhi = West China journal of stomatology 09/2008; 26(4):457-8.
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ABSTRACT: To elucidate the regulatory bio-mechanism of estrogen and local stress on the bone remodeling activities in vivo.
A Wistar rat experimental model was established to apply orthodontic activation during different stages of estrous cycle. In situ hybridization was used to detect the variation of the insulin-like growth factors (IGF) mRNA expression in the periodontal tissues. The data of each group was analyzed with SPSS 11.0 software package for Student-Newman-Keuls (S-N-K) test and one way ANOVA test.
Both IGF-I mRNA and IGF-II mRNA level expressed in the periodontal tissues were increased by orthodontic activation during various stages of the estrous cycle. But a similar pattern emerged that the IGF-I mRNA level was the lowest in the estrous stage, whereas its level was the highest in the proestrus stage (P < 0.05). No rhythm of IGF-II mRNA expression found during the estrous cycle.
It was concluded that local mechanical stimulation directly enhanced the IGF expression. In contrast to the IGF-II, IGF-I was also influenced by the sex hormone rhythm during the estrous cycle.
Hua xi kou qiang yi xue za zhi = Huaxi kouqiang yixue zazhi = West China journal of stomatology 08/2008; 26(4):439-42.
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ABSTRACT: The purpose of this article was to investigate the changes of the estrogen and insulin-like growth factors (IGF) level induced by orthodontic tooth movements in order to elucidate the bio-mechanism of orthodontic treatments during the estrous cycle.
A Wistar rat experimental model was established to apply orthodontic activation during different stages of estrous. The serum and periodontal tissue estradiol level were determined by radioimmunoassay and immunohistochemistry. In situ hybridization was also used to detect the variation of the IGF mRNA expression in the periodontal tissues. The data of each group was analyzed with SPSS 11.0 software package.
Both serum and periodontal estradiol level were increased by orthodontic activation during various stages of the estrous. IGF mRNA expression were also enhanced with the same trend. The estradiol and IGF- I level showed in a similar pattern during the estrous cycle and the rhythm was not changed by the orthodontic activation. There was no rhythm of IGF-II expression found in the estrous cycle.
It was concluded that estrogen and IGF were involved in the remodeling activities induced by the orthodontic activation. The speed of the orthodontic tooth movements was closely related to the estrous cycle.
Hua xi kou qiang yi xue za zhi = Huaxi kouqiang yixue zazhi = West China journal of stomatology 07/2008; 26(3):327-30.
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ABSTRACT: To assess the outcome of orthodontic treatment for adolescents with congenital missing teeth using the PAR (Peer Assessment Ration) index.
The PAR index was adopted to evaluate and compare the teeth arrangement, molar occlusion, overjet, overbite and centerline condition of 20 adolescents with congenital missing teeth before and after orthodontic treatments.
The initial PAR scores and weighted PAR total scores decreased significantly after Orthodontic treatments (P < 0.01), except for the centerline. The PAR total scores decreased by 14.25 +/- 7.91 (80.90% +/- 11.09%). The weighted PAR total scores decreased by 15.45 +/- 8.16 (75.34% +/- 18.41%).
PAR index can well reflect the improvement of occlusion characters by orthodontic treatment for adolescents with congenital missing teeth. But further improvement is needed for clinical application.
Sichuan da xue xue bao. Yi xue ban = Journal of Sichuan University. Medical science edition 06/2008; 39(3):478-80.
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ABSTRACT: The conventional methods on making double splints in presurgery of skeletal Class III were complicated. To find an easy method for the improvement of the production of splints and simplify the making process, 17 severe skeletal Class III patients accepted bimaxillary surgery after making double splints were used. According to visual treatment objective (VTO) forecasting on the lateral cephalometric radiograph of ending presurgical orthodontics and analyzing study models, the surgical methods were designed, the mobile osteotomy bone volume was estimated and the maxillary abnormity was classified. For the patients with right midline and without adjusting their occlusion plane, use the single model method (antedisplace maxillary model twice) or double models method (antedisplace maxillary model firstly, and then retrodisplace mandibular model) to make the double splints which guided the fixtion of bimaxillary surgery through their parallel models and simple articulators. The making process of the double splints was simplified and improved, and the postsurgery effects of all patients were satisfied. Therefore, for making the double splints of skeletal Class III bimaxillary surgery, utilizing the proper method on the basis of the specific abnormal conditions of patients can simplify the production process and get twice the result with half the effort.
Hua xi kou qiang yi xue za zhi = Huaxi kouqiang yixue zazhi = West China journal of stomatology 05/2008; 26(2):219-21.
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ABSTRACT: To investigate the changes of the serum and local estrogen level during orthodontic tooth movements and attempt to elucidate the bio-mechanism of orthodontic treatment.
A Wistar rat experimental model was established to apply orthodontic activation during different stages of estrous cycle. One hundred and twenty female rats were randomly divided into sham-operated group, activation group and control group. Each group was further divided into 4 sub-groups according to the different stage of the estrous cycle. The serum and periodontal tissue estradiol level were determined by radioimmunoassay and immunocytochemistry. The data of each group was analyzed with SPSS11.0 software package for Student-Newman- Keuls(S-N-K) test, and cosinor-rhythmometry method was used for chronobiologic analysis to show the rhythmic change of the estrogen level.
Both serum and periodontal estradiol expression were increased by orthodontic activation during various stages of the estrous cycle (P<0.05). But the rhythm of the estradiol level during the estrous cycle was not changed.
It is concluded that local mechanical stimulation directly enhances the periodontal tissue estrogen expression and inferred that the stress induced by orthodontic activation is related to the serum estrogen augmentation.
Shanghai kou qiang yi xue = Shanghai journal of stomatology 12/2007; 16(6):618-22.
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ABSTRACT: To explore certain principle of how osteoprotegerin (OPG) and osteoprotegerin ligand (OPGL) take part in the periodontal tissues remodeling under the combined influence of inflammation and orthodontic force.
The positive signals of OPG and OPGL mRNA were measured with in situ hybridzation after orthodontic tooth movement in the experimental periodontitis groups and control ones.
The OPG and OPGL mRNA expression intensity in the experimental group showed difference from control. All their optical density index reached a peak in day 2, respectively.
OPG and OPGL play important roles in the periodontal reconstruction induced by inflammation irritation and orthodontic force, and complex interaction could exist between the two factors.
Hua xi kou qiang yi xue za zhi = Huaxi kouqiang yixue zazhi = West China journal of stomatology 11/2007; 25(5):497-9, 503.
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ABSTRACT: To investigate the early effects of the cyclic uniaxial compressive stress on Actin and Vimentin of the rat condylar chondrocyte.
The third-passage chondrocyte were harvested from the mandibular condyles of 2-day-old rats, and a cellular compressive stress device was used to apply stress on cells at 4 000 microstrain for 15, 30, 60, 120, 240 min. The early effects of the cyclic uniaxial compressive stress on Actin and Vimentin of the rat mandibular condylar chondrocytes were examined by laser scanning confocal microscope (LSCM), immunofluorescence technique and Western blot.
The expression of fluorescent light of cys-toskeleton protein changed obviously with 4000 microstrain compressive stress loading. The expression of Actin significantly decreased in 60 min, and the expression of Vimentin decreased in 30 min. Then the expression of these two protein recovered in 120 min.
There are time-responsiveness between the 4000 microstrain compressive stress stimulate and Actin, Vimentin. It shows the expression of Actin and Vimentin down-regulated at first under the compressive stress, then increased by feedback. It hints that there are "self-regulate" mechanisms in the cell response to mechanics stimulate.
Hua xi kou qiang yi xue za zhi = Huaxi kouqiang yixue zazhi = West China journal of stomatology 11/2007; 25(5):422-5.
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ABSTRACT: To investigate the protein profile after treatment of the cyclic uniaxial compressive stress on the rat condylar chondrocyte in vitro.
The third-passage chondrocytes were harvested from the mandibular condyles of 2-day-old rats, and a cellular compressive stress device (self-made four-point bending system) was used to apply stress on cells at 2000 microstrain and 4000 microstrain (0.5 Hz frequency) for 60 min. The early effects of cyclic uniaxial compressive stress on the protein profile of the rat mandibular condylar chondrocytes were examined by two dimensional polyacrylamide gel electrophoresis (2D-PAGE) and matrix-assisted laser-desorption ionization time of flight mass spectrometry (MALDI-TOF-MS).
The results showed that the protein profile of the condylar chondrocyte did not change statistically in 2000 microstrain group. In 4000 microstrain group, the protein profile of the condylar chondrocyte was changed. Three new proteins appeared. Five proteins disappeared. Twenty-two proteins were down-regulated and 7 proteins were up-regulated (P < 0.05). The eight different protein spots were identified by MALDI-TOF-MS. It included cytoskeleton protein (gamma-actin and vimentin), glycometabolism protein (alpha enolase and stress-70 protein) and signal transduction protein (Raf kinase inhibited protein, RKLP).
There were significant alternations of the protein profile in the rat condylar chondrocyte after the 4000 microstrain cyclic uniaxial compressive stress loading for 60 min. These different proteins might take part in the early response to the cyclic uniaxial compressive stress.
Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology 10/2007; 42(9):529-32.
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ABSTRACT: To perform qualitative and quantitative analyses of core binding factor alpha1 (cbfalpha1) in periodontal tissue during the experimental rat tooth movement process and to investigate the active mechanism of cbfalpha1 in the osteoblast differentiation.
42 male Wistar rats aged 8 weeks were divided into 7 groups (0,1,3,5,7,10 and 14 days groups) in random, 6 rats in each group. 42 rats were perfused and sacrificed at the 1st, 3rd, 5th, 7th, 10th and 14th day. All specimens were fixed, then proceeded with HE and cbfalpha1 immunohistochemical staining. The results were analyzed by SPSS11.0 software package for Dunnett test, and the histological changes of cbfalpha1 in periodontal tissue were evaluated.
In the periodontal ligament(PDL) of non orthodontic treatment group, the expression of cbfalpha1 was lower; the expression of cbfalpha1 in every experimental groups increased firstly and decreased later; the expression of cbfalpha1 in the surface of the alveolar bone was lower in the compression side than in the tension side, and the number of positive cells was less too (P<0.01).
cbfalpha1 participates in the process of bone remodeling during the process of orthodontic tooth movement, and it promotes the remodeling and stability of PDL.
Shanghai kou qiang yi xue = Shanghai journal of stomatology 10/2007; 16(5):507-11.
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ABSTRACT: Through orthodontic tooth movement in the pregnant and non-pregnant rats, to investigate the osteopontin (OPN) mRNA expression pattern in the periodontal tissues, and to probe its possible roles in orthodontic periodontal remodeling.
Fixed appliances were used to mesially move the rats' maxillary first molars. In situ hybridization method was used to detect the expression changes of OPN mRNA in periodontal tissues.
Compared to the non-pregnant rats, the expression of OPN mRNA in periodontal cells of the pregnant rats was more intensive. During the gestational period, the expression intensity had significant difference at different pregnant stages. The highest expressions occurred at the mid-pregnant stage, less at the late-stage and lest at the early-stage.
Under the pregnant state, the expression of OPN mRNA in periodontal tissues may be up-regulated by increased serum progesterone level.
Hua xi kou qiang yi xue za zhi = Huaxi kouqiang yixue zazhi = West China journal of stomatology 07/2007; 25(3):302-5.
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ABSTRACT: To investigate the changes in expression of gelatinase (MMP-2, MMP-9) in young rat condylar cartilage during functional mandibular advancement.
Sixty male 5-week old SD rats were divided into experimental and control groups. The mimic functional appliances were used in experimental group rats. The animals were sacrificed after 1, 2, 4 weeks. The immunoreactivity of gelatinase was detected by immunohistochemistry.
In normal mandibular condylar cartilage, the immunoreactivity of MMP-2 was rather strong, the immunoreactivity of MMP-9 was very weak. Following functional mandibular advancement, the expression of MMP-9 was significantly increased (P < 0.01), but immunoreactivity of MMP-2 had no significant changes.
Gelatinase plays an important role in the adaptive remondling of young rat condylar cartilage during functional mandibular advancement.
Hua xi kou qiang yi xue za zhi = Huaxi kouqiang yixue zazhi = West China journal of stomatology 07/2007; 25(3):299-301, 305.
