Assessing changes in quality of life using the Oral Health Impact Profile (OHIP) in patients with different classifications of malocclusion during comprehensive orthodontic treatment.

BACKGROUND: The objectives of this study were to investigated changes in OHRQoL among patients with different classifications of malocclusion during comprehensive orthodontic treatment. METHODS: Clinical data were collected from 81 patients (aged 15 to 24) who had undergone comprehensive orthodontic treatment. Participants were classified 3 groups: Class I (n = 35), II (n = 32) and III (n = 14) by Angle classification. OHRQoL was assessed using the Oral Health Impact Profile (OHIP-14). All subjects were examined and interviewed at baseline (T0), after alignment and leveling (T1), after correction of molar relationship and space closure (T2), after finishing (T3). Friedman 2-way analysis of variance (ANOVA) and Wilcoxon signed rank tests were used to compare the relative changes of OHRQoL among the different time points. A Bonferroni correction with P < 0.005 was used to declare significance. RESULTS: Significant reductions were observed in all seven OHIP-14 domains of three groups except for social disability (P > 0.005) in class I and class II, Handicap in class II and class III (P > 0.005). Class I patients showed significant changes for psychological disability and psychological discomfort domain at T1, functional limitation, physical pain at T2. Class III patients showed a significant benefit in all domains except physical pain and functional limitation. Class II patients showed significant changes in the physical pain, functional disability, and physical disability domains at T1. CONCLUSIONS: The impact of comprehensive orthodontic treatment on patients' OHRQoL do not follow the same pattern among patients with different malocclusion. Class II patients benefits the most from the stage of space closure, while class I patients benefits the first stage (alignment and leveling) of treatment in psychological disability and psychological discomfort domains.

[Effect of collagen sponge on the healing process of alveolar fossa after tooth extraction in rats].

PURPOSE: To investigate the effect of collagen sponge on early bone healing process of alveolar fossa after tooth extraction in rats. METHODS: A total of 16 healthy female SD rats were selected. Animal models with tooth extraction were established. The right alveolar fossa inserted with collagen sponge was as the experimental group, and the left alveolar fossa was as the control group with treatment. The rats were sacrificed 1, 2, 4 and 8 weeks after tooth extraction, and the osteogenesis of alveolar fossa was observed. Real-time quantitative PCR (qt-PCR) was used to detect the changes of osteogenesis related gene expression. SPSS 19.0 software package was used for statistical analysis. RESULTS: After surgery, alveolar cavity healing was significantly better in the experimental group than in the control group. Osterix, Runx2 and Vegf genes were expressed in the experimental group and the control group, and the expression levels of related genes in the experimental group were significantly higher than the control group 1, 2, 4 and 8 weeks after surgery(P＜0.05). CONCLUSIONS: Collagen sponge could promote early alveolar bone healing, possibly related to the expression level of osteogenic genes regulated by collagen sponge.

[Effect of ipriflavone on reconstruction of periodontal tissues during recurrence of orthodontic teeth in rats].

PURPOSE: To investigate the effect of ipriflavone on reconstruction of periodontal tissues during recurrence of orthodontic teeth. METHODS: Twenty-four male SD rats were randomized into 2 groups, ipriflavone group(IP group) and control group, there were 12 rats in each group. The model of recurrence after movement of orthodontic teeth in rats was established. After continuous loading for 10 days, the loading devices were removed. Rats in ipriflavone group (IP group) were given ipriflavone intragastrically for 10 mg/(kg·d) after the devices were removed, while rats in the control group were given an equivalent amount of normal saline after the devices were removed. On the 0th, 1st, 3rd, 7th, and 10th day of administration, the rat maxillary impression and plaster model of two groups were prepared under local anesthesia, the distance between maxillary first molar lingual sulcus point and third molar in lingual groove point was measured to evaluate the relapse distance. After drug infusion for 10 days, the collected tissue specimens were stained with H-E to observe periodontal reconstruction, and expression of bone morphogenetic protein-2(BMP-2) was detected by immunohistochemical staining. Software Image-Pro 6.0 was used to analyze the optical density values of the stained sections. The data were analyzed with SPSS 22.0 software package. RESULTS: After removing the orthopaedic devices for 10 days , there was a significant recurrence of the movement of the orthodontic teeth in both groups. The recurrent distance of IP group was significantly smaller than that of the control group, and still significantly smaller than that of the control group at 10 d. H-E staining and immunohistochemical staining results showed that the IP group had more new bone formation and more BMP-2 expression in the periodontal tissues compared to the control group in vivo. CONCLUSIONS: In the process of recurrence of orthodontic tooth movement, ipriflavone can promote the expression of BMP-2 in periodontal tissue, improve bone remodeling of periodontal tissue, and effectively reduce the recurrent rate of orthodontic tooth movement.

Root shortening in patients treated with two-step and en masse space closure procedures with sliding mechanics.

OBJECTIVE: To investigate the comparative amount of root shortening between two-step and en masse space closure procedures. MATERIALS AND METHODS: Fifty-two patients were selected from a pool of patients satisfying the following inclusion criteria: no evidence of resorption on the pretreatment panoramic radiographs; no dental trauma; no dilacerations of incisor roots, anodontia, or impacted canines; complete root formation at the start of treatment; intact and caries-free incisors; no endodontically treated incisors; Angle Class I or II malocclusion; extraction of four first premolars; and space closure with moderate anchorage. Patients received treatment with either a two-step or an en masse procedure to close the extraction spaces after alignment and leveling with the same preadjusted appliances. Root shortening of the maxillary and mandibular incisors was evaluated on panoramic radiographs, taken before and after space closure, and measured in millimeters. Distortion of measurements caused by panoramic radiographs was corrected by using special metal rods ligated to brackets. Statistical comparisons of root shortening between space closure procedures were investigated with the two-sample t test. RESULTS: No difference was found in the amount of root shortening between space closure procedures. The average root shortening of maxillary central and lateral incisors was 0.43 +/- 0.12 mm and 0.58 +/- 0.10 mm, respectively, and that of mandibular central and lateral incisors was 0.23 +/- 0.07 mm and 0.22 +/- 0.06 mm, respectively. CONCLUSION: No difference should be expected in root resorption between two-step and en masse space closure procedure.

The effects of binge alcohol exposure on tooth movement and associated root resorption in rats.

BACKGROUND: Considering the increasing prevalence of alcohol use and the growing number of orthodontic patients, some orthodontic patients might engage in binge drinking during treatment. Nevertheless, little is known about the effect of alcohol use on orthodontic treatment. METHODS: Male Wistar rats were divided into ethanol and control groups (n = 32). The rats received a single daily intraperitoneal injection of 20% (vol/vol) ethanol/saline solution at a dose of 3 g/kg of ethanol or saline for three consecutive days, and no injection was given during the remaining four days each week. All rats received orthodontic appliances to draw the maxillary first molar mesially. The rats were sacrificed at days 14 and 28, respectively. The amount of tooth movement was measured. Root resorption area was evaluated by scanning electron microscope. Hematoxylin and eosin (H&E) staining and tartrate-resistant acid phosphatase (TRAP) staining were conducted. Immunohistochemistry staining was performed to evaluate the expressions of nuclear factor kappa B ligand (RANKL), osteoprotegerin (OPG), and inducible nitric oxide synthase (iNOS). RESULTS: There were no significant differences in tooth movement and root resorption between ethanol and control groups. The number of TRAP-positive cells was significantly higher in the ethanol group. The expression of RANKL was statistically increased in the ethanol group. In contrast, the expression of OPG was remarkably decreased in rats injected with ethanol. Moreover, the iNOS level was significantly up-regulated in the ethanol group. CONCLUSION: The tooth movement and root resorption in rats were not affected by binge alcohol exposure.

Inhibitory effects of resveratrol on orthodontic tooth movement and associated root resorption in rats.

OBJECTIVE: To investigate the effect of resveratrol (RSV) on orthodontic tooth movement (OTM) and orthodontic induced root resorption (OIRR) in rats. METHODS: Thirty-six male Wistar rats used in this study were randomly divided into three groups of 12 animals each. All test subjects underwent a 50 g orthodontic force each, generated from a nickel-titanium closed-coil spring. The control group were fed carboxymethylcellulose (CMC) while rats in other two groups were fed 5 mg/kg/d RSV or 10 mg/kg/d RSV (dissolved in CMC). After 14 days of OTM, all rats were sacrificed, after which each group was randomly divided into two subgroups (6 test subjects in each subgroup). One subgroup was used to measure the amount of OTM and assessed by hematoxylin and eosin (HE) staining, tartrate-resistant acid phosphatase (TRAP) staining, and immunohistochemistry staining of Receptor Activator of Nuclear Factor-κ B Ligand (RANKL), Osteoprotegerin (OPG), Runt-related transcription factor 2 (RUNX2), as well as Osteocalcin (OCN). The second subgroup was used to analyze OIRR via scanning electron microscopy. RESULTS: Compared with the control group, the RSV groups showed a significant decrease in the distance of OTM and the OIRR ratio (p＜0.05). The number of TRAP positive osteoclasts and the expression of RANKL in periodontal tissue of the RSV groups were significantly inhibited (p＜0.01) while the expression of OPG, RUNX2, and OCN were remarkably promoted (p＜0.05). The effect of 10 mg/kg/d RSV group was more obvious than that of 5 mg/kg/d RSV group (p＜0.05). CONCLUSIONS: RSV could reduce the extent of OTM and root resorption areas.

[Effect of psoralen on the stability after orthodontic tooth movement in rats].

PURPOSE: This study was designed to investigate the effect of psoralen on periodontal tissue reconstruction after orthodontic tooth movement(OTM) in rats. METHODS: Thirty-six male 6-week-old Wistar rats were randomly divided into 2 groups: the experimental group and the control group. The experimental group and the control group were all installed between the central incisor and the left maxillary first molars to pull the first molars away from the force device; after 21 days, the force was removed and the rats in 2 groups were given drug gavage. Rats in the experimental group were given a gavage of psoralen 8 mg/kg per day, while rats in the control group were given the same amount of 0.9% sodium chloride everyday. Maxillary casts were made every week during the experimental and were scanned by 3D Scanner to measure relapse distance, and histologic examination was conducted. After 28 days, the rats were sacrificed and rats' upper jaw was separated. The remaining sections were immunohistochemically stained with BMP2 and BMP4. SPSS 19.0 software package was used for statistical analysis. RESULTS：Both groups had relapse after the force device was removed. Significant decrease of relapse percentage was observed in the experimental group compared with the control group at day 7，day 14，day 21 and day 28（P<0.05）. The speed of relapse of both groups were fastest in the first week and slowed down in the second, third and fourth week gradually. The speed of relapse in the experimental group in the first week was significantly less than in the control group(P<0.05).The expression of BMP2 and BMP4 within periodontal membrane and alveolar bone was significantly higher in the experimental group than in the control group(P<0.05). CONCLUSIONS: Psoralen can accelerate the reconstruction of periodontal tissues of orthodontic tooth and reduce relapse.

[Effect of osthole on periodontal remodeling during orthodontic tooth movement in rats].

PURPOSE: To investigate the effect of osthole on periodontal remodeling during orthodontic tooth movement (OTM) in rats. METHODS: Seventy two 8-week-old male SD rats were randomly equally divided into 3 groups: two experimental groups of osthole with low (20 mg/kg) and high (40 mg/kg) concentration and the control group. Models of OTM were routinely established. Rats in the experimental groups were respectively given osthole by intragastric administration, while rats in the control group received the same volume of solvent. The rats were sacrificed on 7th, 14th, 21st and 28th day after orthodontic treatment, and the maxilla was harvested and the distance between the first and second molar was measured in each stage. Hematoxylin-eosin (H-E) staining, tartrate resistant acid phosphatase (TRACP) staining were performed. The results were analyzed with SPSS 20.0 software package for one-way analysis of variance. RESULTS: The mesio-moving distance of the three groups successively increased gradually. On the 7th day, there was no difference between the low concentration group and the control group (P>0.05); at other time point, the experimental groups exhibited significant differences from the control group(P<0.05), and the high concentration group had more obviously mesio-movement than the low concentration group(P<0.05). Histological observation showed that in the tension side, osteoblast appeared, but more apparent in the experimental groups than in the control group. In the pressure side, the number of osteoclast reached the peak at the 7th day, and much more osteoclasts were seen in the experimental groups than in the control group (P<0.05), in high concentration group than in low concentration group (P<0.05). The number of osteoclast decreased subsequently, but significant difference existed between the experimental groups and the control group (P<0.05) on the 14th day. At other time points, there was no significant difference among the three groups(P>0.05). CONCLUSIONS: Osthole could increase the number of osteoclast in periodontium and promote bone remodeling at the early stage of treatment, its effect is dose-dependence during OTM.

Effects Of Triptolide On Tooth Movement And Root Resorption In Rats.

PURPOSE: The aim of this study was to investigate the effects of triptolide on the tooth movement and root resorption in rats during orthodontic treatment. MATERIAL AND METHODS: A total of 48 male Wistar rats were divided into three groups of 16 each. The right maxillary first molars of rats were drawn mesially by closed coil nickel-titanium spring with a force of 50 g. The two experimental groups received intraperitoneal injections of triptolide for 14 days at a dose of 15 µg/kg/day and 30 µg/kg/day, respectively. The control group received vehicle injections. After 14 days, the rats were humanely killed. The amount of tooth movement was measured. Eight rats from each group were randomly chosen for analysis of the percentage of root resorption area by scanning electron microscopy. For the remaining eight rats in each group, the H&E staining, tartrate-resistant acid phosphatase (TRAP) staining and immunohistochemistry analysis were performed. RESULTS: The amount of tooth movement and the ratio of root resorption area were significantly decreased in the triptolide-treated rats. The number of TRAP-positive cells was significantly lower in triptolide-treated groups. Moreover, the expression of nuclear factor kappa B ligand (RANKL) was reduced. In contrast, the expression of osteoprotegerin was significantly up-regulated. In the tension side, the expressions of runt-related transcription factor 2 and osteocalcin were significantly enhanced by triptolide injection. CONCLUSION: Triptolide injection could arrest orthodontic tooth movement and reduce root resorption in rats via inhibition of osteoclastogenesis. In addition, triptolide may exert a positive effect on osteoblastogenesis.

Muscone Promotes The Adipogenic Differentiation Of Human Gingival Mesenchymal Stem Cells By Inhibiting The Wnt/ß-Catenin Signaling Pathway.

OBJECTIVES: This study was performed to evaluate the effects of muscone on the proliferation, migration and differentiation of human gingival mesenchymal stem cells (GMSCs) and to explore the relevant mechanisms. MATERIALS AND METHODS: We performed studies to determine the effects and mechanisms of muscone on GMSC proliferation, migration and differentiation. We conducted CCK-8, colony formation, transwell chamber, scratch wound, alkaline phosphatase (ALP) staining and activity, and alizarin red and oil red O staining assays, as well as real-time quantitative polymerase chain reaction (qRT-PCR), to ascertain the effects of muscone on GMSC proliferation, migration and differentiation in vitro. The mechanism by which muscone influences the osteogenic and adipogenic differentiation of GMSCs was elucidated by qRT-PCR and Western blotting. RESULTS: We found that muscone significantly promoted GMSC proliferation, chemotaxis, wound healing and fat droplet formation and inhibited ALP activity and mineral deposition. Notably, we observed that the Wnt/ß-catenin pathway was closely related to the ability of muscone to inhibit the osteogenic differentiation and promote the adipogenic differentiation of GMSCs. The effect of muscone on the multidirectional differentiation capacity of GMSCs was significantly reversed by the agonist lithium chloride through the Wnt/ß-catenin signaling pathway. CONCLUSION: Muscone effectively increased the proliferation and migration, promoted the adipogenic differentiation and inhibited the osteogenic differentiation of GMSCs by inhibiting the Wnt/ß-catenin signaling pathway. These results may provide a theoretical basis for the application of GMSCs and muscone in tissue engineering and regenerative medicine.

Effects of Btbd7 knockdown on the proliferation of human dental pulp cells and expression of Dspp.

BTB/POZ domain-containing protein 7 (Btbd7) is recognized as a regulatory gene that promotes epithelial tissue remodeling and branching morphogenesis. In cancer cells, it is involved in epithelial-mesenchymal transition and cell invasion. However, the role of Btbd7 in human dental pulp cells (hDPCs) is not clear. The aim of this study is to explore the function of Btbd7 in hDPCs. Expression of Btbd7 in hDPCs was examined by immunocytochemical staining. Lentiviral vectors expressing small interfering RNA (siRNA)-Btbd7 were used to knockdown expression of Btbd7 in hDPCs. Proliferation of Btbd7 knockdown hDPCs was determined using a cell counting Kit-8 assay, and expression of dentin sialophosphoprotein (Dspp) was assessed using real-time quantitative reverse transcription-PCR and Western blot. Btbd7 was mainly expressed in the cytoplasm and nucleus of hDPCs. Suppression of Btbd7 temporarily promoted hDPC proliferation and significantly inhibited expression of Dspp in hDPCs. Our results show that Btbd7 plays a role in hDPC proliferation, and possibly participates in odontoblast differentiation of hDPCs and dentin formation by regulating the expression of Dspp.

[Effect of akebiasaponin D with different concentrations on orthodontic tooth movement in rats].

PURPOSE: This study investigated the effect of local injection of akebiasaponin D (ASD) with different concentrations on the rate of orthodontic tooth movement in rats. METHODS: Forty 6-week-old female Wistar rats were randomly divided into 4 groups with 10 rats in each group. Animal model for orthodontic tooth movement was established. The upper first molars of the rats were moved mesially by coil springs（force=40 g）. ASD solution at the concentration of 5 mg/kg was locally injected in ASD1 group, and ASD solution at the concentration of 10 mg/kg was locally injected in ASD2 group. The rats of group PGE2 were injected PGE2 solution at the concentration of 25 µg/kg. The same amount of normal saline was injected in the control group. The rats were sacrificed in batch on the 3rd, 7th, 14th, 21st and 28th days after orthodontic treatment. The distance between upper first molar and second molar was measured. H-E straining was performed to observe the changes of periodontal tissue and the amount of osteoclast. SPSS13.0 software package was used for statistical analysis. RESULTS: The distance between the first and second molar was successively increased compared with the control group. On day 3, there was significant difference between PGE2 group and the control group (P＜0.05). On day 7, the distance between the first and second molar in PGE2 group and ASD2 group was significantly increased compared with the control group (P＜0.05). The amount of tooth movement was significantly increased (P＜0.05) in ASD1 group, ASD2 group and PGE2 group, compared with the control group on the 14th, 21st and 28th day. However, there was no significant difference (P＞0.05) between ASD2 group and PGE2 group. Under microscope, the number of osteoclast was increased on the tension side, reaching a peak on day 21st, and decreased later. CONCLUSIONS: Local injection of ASD solution may accelerate orthodontic tooth movement. ASD solution at the dose of 10 mg/kg can accelerate orthodontic tooth movement efficiently similar to PGE2 solution, while ASD solution at the dose of 5 mg/kg is not as effectual as PGE2 solution.

[Influence of fixed orthodontic treatment on oral health-related quality of life in adolescent and adult: a comparative study].

PROPOSE: To compare the changes in oral health-related quality of life(OHRQoL) among adolescent patients and adult patients during orthodontic treatment. METHODS: The clinical data were collected from 81 patients (aged 15 to 25 years old) who underwent comprehensive orthodontic treatment. The participants were divided into 2 groups: adolescent patients (n=43) and adult patients (n=38) by age. OHRQoL was assessed using the Oral Health Impact Profile (OHIP-14). All subjects were examined and interviewed at baseline and the end of 3 stages during orthodontics treatment. Friedman 2-way analysis of variance (ANOVA) and Wilcoxon signed rank tests were used to compare the relative changes of OHRQoL among different time points with SPSS 20.0 software package. RESULTS: The scores of OHIP-14 and all domains except communication disorder and social disability domain in adolescent and adult patients showed significant changes as well as a decrease trend. Only adults showed significant changes in communication disorder.Both groups had no significant difference. CONCLUSIONS: The impact of comprehensive orthodontic treatment on patients' OHRQoL is quite different. Orthodontists should pay attention to the differences and guide the patients accordingly.

Upper airway asymmetry in skeletal Class III malocclusions with mandibular deviation.

The purpose of this study was to investigate the relationship between bilateral differences of upper airway and mandibular morphologic patterns in subjects with skeletal Class III mandibular deviation. 47 skeletal Class III (ANB < 0°) adult patients with and without mandibular deviation were divided into 2 groups. Bilateral differences of minimum cross-sectional area, mean cross-sectional area, volume of subdivisions (nasopharynx, palatopharynx, glossopharynx, hypopharynx) were assessed paired t test. Stepwise linear regression analysis and Pearson correlation coefficients were computed between a significant pair of upper airway variables and a pair of mandibular deviation variables to examine the quantitative relationship between the upper airway asymmetry and mandibular deviation. The mean cross-sectional area and the volume of palatopharynx on the deviated side in mandibular deviated group was significantly smaller than non-deviated side. The asymmetry index of the palatopharyngeal volume showed significant correlations with CRA asymmetry (r = 0.49) and Ramus asymmetry (r = 0.54). However, in the glossopharyngeal and hypopharyngeal segment, the mandibular deviated group showed significant asymmetry, characterized by larger mean cross-sectional area and volume in deviated side. The asymmetry index of the glossopharyngeal volume and hypopharyngeal volume showed significant correlations with CRA asymmetry (r = 0.42), Me-s (r = 0.72) and Me-s (r = 0.67) respectively.

[Effect of icraiin on turnover of alveolar bone during orthodontic tooth movement in rats].

PURPOSE: To observe the effect of icariin on turnover of paradentium as well as the mechanism of effects on osteoclast during orthodontic tooth movement in rats. METHODS: Forty-right SD rats were used to establish animal models of OTM and divided into two groups randomly: the control group and the experimental group. Rats in the experimental group were given 20 mg/（kg.d） icariin by intragastric administration, while rats in the control group received solvent with the same volume. The rats were sacrificed in batch on the 7th, 14th, 21st and 28th day after orthodontic treatment. The amount of tooth movement was measured, and histomorphometric analysis based on slices from periodontium adjacent to the maxillary first molars was used to observe new bone formation, bone resorption and quantify osteoclasts. Statistical analysis was performed by using SPSS 16.0 software package. RESULTS: The movement distance of the first molar was significantly larger in the icariin group than that in the control group (P<0.05). In the icariin group, the number of osteoclasts was significantly higher than the control group at the 7th day and then demonstrated a steady decrease. CONCLUSIONS: Icariin could accelerate OTM in rats through promoting bone turnover of alveolar bone.

[Effects of strontium ranelate on the expression of BMP-2 in the mid-palatal suture of rats during rapid maxillary expansion].

PURPOSE: To investigate the effects of strontium ranelate on the expression of BMP-2 during rapid maxillary expansion. METHODS: Thirty-six male 6-week- old male Wistar rats were selected. They were randomly divided into 3 groups. Group A was designed as a control group. An expanded application producing 100 g force was fixed between the first and the second molar on both sides of the rats in group B and group C. 600 mg/kg strontium ranelate was given to the rats in group C daily via an orogastric route, while the equal normal saline was given to the rats in group B. Then the rats were sacrificed on day 4, 7 and 10. The expression of BMP-2 which is a sign of bone formation was detected with immunohistochemical staining and analyzed with Image-pro plus 5.0. SPSS19.0 software package was used for statistical analysis. RESULTS: The expression of BMP-2 in the midpalatal suture was significantly greater in group B than that in group A on day 4 (P<0.05); however, there was no significant difference between group A and group B on day 7 and 10 (P>0.05). The expression of BMP-2 in the midpalatal suture in group C was significantly greater than that in the other two groups at each time point (P<0.05). CONCLUSIONS: Strontium ranelate promotes the expression time and quantity of BMP-2 in the mid-palatal suture of rats during rapid maxillary expansion and may accelerate bone formation during rapid maxillary expansion.

Effects of icariin on orthodontic tooth movement in rats.

PURPOSE: Orthodontic tooth movement (OTM) is achieved through bone remodeling of the alveolar bone. Icariin, the active ingredient isolated from Herba Epimedii which is a traditional Chinese medicine (TCM) commonly used for osteoporosis treatment in China. The purpose of the study is to explore the effect of icariin on OTM in rats, and analyze the possible mechanism involved. METHODS: 48 rats were selected and divided into 2 groups: the control group and the experimental group. Rats in the experimental group were given 20 mg/kg/day icariin by intragastric administration, while the control group received the same volume solvent. All rats were placed a closed coil spring between their upper first molar and incisor, exerting a force of about 40 g to establish animal models of OTM. As the first molar moved mesially, a space between the first and second molar was created. The rats were sacrificed in batch on the 7th, 14th, 21st and 28th days after orthodontic treatment. The amount of tooth movement was measured, and histomorphometric analysis based on slices from periodontium adjacent to the maxillary first molars were used to observe new bone formation, bone resorption and quantify osteoclasts. KEY RESULTS: Icariin increased OTM (P<0.05) by 65.2%, 35.3%, 11.7% and 16.7% on day 7, 14, 21, 28 respectively compared with the control group. The number of osteoclasts in the icariin group showed a transient but sudden increase and then a persistent decrease. CONCLUSIONS: Icariin could accelerate OTM in rats through promoting bone remodeling of alveolar bone.

[Correlation analysis between psychosomatic symptoms of adult and cooperation behaviors].

PURPOSE: To investigate whether the psychosomatic symptoms of patients are related to the degree of cooperation. METHODS: Ninety-one malocclusion adults (31 males, 60 females, aged from 20 to 45 years) were selected and determined with Symptom Checklist-90 (SCL-90) to evaluate their psychosomatic symptoms. The inspected and filed noncooperation behaviors were examined and recorded 6 months after orthodontic treatment started. The data was analyzed by one-sample t test, independent-sample t test and Spearman rank correlation coefficient with SPSS 20.0 software package. RESULTS: Adult malocclusion patients scored significantly higher than the nation norm on the factors of interpersonal sensitivity, anxiety, schizophrenia and compulsion (P<0.05). The score of noncooperation behaviors showed a scale of 0 to 19, with an average of 7.2 ± 1.4 points. There was positive correlation between psychological problems and noncooperation behaviors of adult patients (r=0.35). CONCLUSIONS: The study confirms that the psychosomatic symptoms of adult malocclusion patients are associated with the degree of cooperation. Having known well about the psychology of adult malocclusion patient before orthodontic treatment is initiated, and orthodontists can relieve psychological disorders in patients to improve their cooperating quality.

[Three-dimensional finite element analysis of different reactive force direction of maxillary protraction on temporomandibular joint].

OBJECTIVE: To analyze the influence of different reactive force direction of protractions on temporomandibular joint (TMJ) by establishing a three-dimensional finite element model (FEM) of craniomaxillofacial complex. METHODS: The CT image of the head of a healthy young male volunteer was obtained.With the help of Mimics software, we established a three-dimensional finite element model of craniomaxillofacial complex which included TMJ. The force pattern of maxillary protraction appliance was imitated. The force (5 N) was applied on the chin and the direction of force was from 22° to 49° relative to the occlusal plane. The displacement and stress distribution of TMJ were analyzed. RESULTS: The contact stress on the maxilla decreased with the angle of the force direction increased from 22° to 40°, and increased with the angle increased from 40° to 49°. The stress on the condyle decreased with the angle of the force direction increased. The stress on the condylar neck decreased initially and then increased with the angle of the force direction increased. Comprehensively, the stress was the smallest when the angle of the force direction was 40°. The clockwise rotation of the mandible was found when the angle of the force direction was smaller than 40°. The displacement value was relatively small when the angle was 40°. CONCLUSIONS: Stress and displacement were relatively small when the angle of the force direction was 40° relative to the occlusal plane.

[Effect of pamidronate and ibandronate on orthodontic root resorption in rats].

OBJECTIVE: To compare the effects of pamidronate and ibandronate on orthodontic root resorption. METHODS: Seventy-two 6-week-old female specific pathogen free (SPF) Wistar rats were selected to establish models for orthodontic tooth movement. The rats were randomly divided into three groups: the control group (C group), pamidronate group (Pm group) and ibandronate group (Ib group). 0.9% normal saline,0.5 mmol/L pamidronate and 0.5 mmol/L ibandronate were injected every 3 days. The rats were executed in batch on the 3rd, 7th and 14th day to make tissue sections. All statistical analysis was performed using the PASW Statistics 18 software package. RESULTS: On the 7th and 14th day, the amount of cementoclast, the expression of osteoclast differentiation factor (ODF) and root resorption index were significantly lower in Pm group [the 7th day: (2.675 ± 0.002), (0.1683 ± 0.0007), (0.103 ± 0.003); the 14th day: (3.886 ± 0.048), (0.1873 ± 0.0014), (0.283 ± 0.001)] and Ib groups[the 7th day: (2.601 ± 0.001), (0.1634 ± 0.0010), (0.099 ± 0.002); the 14th day: (3.754 ± 0.019), (0.1818 ± 0.0016), (0.281 ± 0.001)] than in C group[the 7th day: (2.810 ± 0.001), (0.1792 ± 0.0008), (0.120 ± 0.001); the 14th day: (4.800 ± 0.001), (0.2060 ± 0.0007), (0.401 ± 0.001)] (P < 0.05). However, no significant difference was found between Pm and Ib groups on the 3rd, 7th and 14th day (P > 0.05). CONCLUSIONS: Both pamidronate and ibandronate could inhibit orthodontic root resorption.