[Effectiveness of body psychotherapy technique on stress and salivary cortisol level in high school girl students]

Body psychotherapy technique [BPT] is a program teaches to deal more effectively with stressors. This study was done to evaluate the effectiveness of body psychotherapy technique on the stress and salivary cortisol level in high school girl students. In this randomized clinical trials study, thirty 15-18 years old female students were randomly divided into intervention and control groups. BPT group was given to the intervention group in nine sessions during two months. Cohen stress scale was used perior and the end of study to determine the scale of stress. Perior and at the end of study, salivary samples of subjects were collected directly after getting up in the early morning, 15, 30 and 45 minutes later on to measure salivary cortisol level. The mean of stress scale scores and salivary cortisol level in the intervention group significantly reduced in comparison with the controls [P<0.05]. Body psychotherapy technique reduces stress scale scores and salivary cortisol level in high school girl students in Gorgan, northern Iran

Effect of low level laser therapy with the application of DFDBA in rabbits

Low Level Laser Therapy is used in many aspects in medicine and dentistry, such as treatment of bone lesions. The purpose of this study was to evaluate the effect of low level laser [GaAlAs] combined with the application of DFDBA in bone healing of rabbit tibia. The experimental study was done on 12 male albino rabbits with an approximate weight of 1.5 kg and about 6 months of age. In order to perform the surgery, animals were anesthetized with intravenous injection of Ketamin 10% and Xylazine 2%. An artificial lesion was created using implant drills [height of 4 mm and diameter of 2.8 mm] in tibia bone and was filled with DFDBA. Then, the lesions were irradiated using laser with distinct protocol [10 days irradiation, 14 days rest, 10 days irradiation, 14 days rest]. Type of the laser was GaAlAr with wavelength of 808 nm, energy of 6 J/cm[2] and in continuous mode. No irradiation was done in the control group. After 48 days, the animals were sacrificed and sections from tibia was made and the specimens were underwent histological assessments. Wilcoxon signed rank test was performed for evaluating the data. In histological assessment, laser group showed significantly more osteogenesis and angiogenesis [P<0.05]. The findings of the present study show that GaAlAs irradiation together with the application of DFDBA led to improved healing, more angiogenesis, and osteogenesis in bone lesions of rabbit

correlation between third molar size axial angulation, developmental stage and its relative position with possibility of mandibular second molar impaction in prospective possible impaction for lower second molars

Simultaneous formation of third molar crown with second molar eruption may possibly cause to second molar impaction due to third molar bud intervention. A tooth impaction leads to numerous clinical problems for the patient and the present study assessed the effect of third molar size, axis angulation, developmental stage and its bud position with possibility of mandibular second molar impaction in patients with doubtful impaction of lower second molars. In this descriptive-analytical study, 5420 records of 10-12 years old patients underwent orthodontic treatments in Tehran and Shahid Beheshti Dental Schools and private clinics were assessed and 38 patients [26 females and 12 males] were selected with possible impaction of lower second molars forming case group. 38 control patients with no prospective possibility for impaction of second molars were selected from the same centers and matched with the cases. The third molar axis angulation towards second molar, first molar and mandible base, mesiodistal width of wisdom teeth relative to second molar, Nolla developmental stage and third molar bud position regarding second molars were calculated and analyzed by student t, chi-square and mann-whitney U tests in both groups. The mean value of third molar angulation towards second molar, first molar and mandibular base were 24.16, 49.26 and 54.42 degrees in case group and 14.42, 39.39 and 45.0 degrees in control group respectively with significant differences [P<0.001 in three variables]. The mean mesiodistal width of third molar relative to second molar was 0.9903 in case Group and 0.9695 in control Group with no significant differences. Nolla developmental stage and marginal ridge of third molar bud towards second molar showed no definite effect on second molar impaction. The results suggest third molar angulation towards second molar, first molar and mandibular jaw base to be significantly higher in patients with possible mandibular second molar impaction than those without prospective possibility for second molar impaction. Although, no significant differences in mesiodistal width of third molar relative to second molars, developmental stage and marginal ridge of third molar bud regarding second molar were observed between the two groups

[Tissue reactions in the socket preservation using NanoBone[TM] following orthodontic tooth movement]

Bone substitute biomaterials can prevent severe root resorptions during orthodontic treatments by induction of new bone formation leading in more healthy periodontal status after treatment. Furthermore, NanoBone[TM] graft offers several advantages to be applied in the surgery defects due to its nanocrystalline hydroxy apatite components and nanosized biomaterial structures. The purpose of this study was to evaluate the tissue reactions in the socket preservation using NanoBone[TM] following orthodontic tooth movement. In this experimental study, 4 dogs were selected of the mixed race following defects preparations in the mesial aspect of the first premolar in each quadrant of the animals. NanoBone[TM] was applied in one side as a case region while the opposite side remained hollow as a control side. The first premolar was moved mesially using orthodontic forces and the orthodontic tooth movement was calculated at different time intervals. When the teeth reached half the way, the animals were sacrificed and the sections were subjected to histopathologic assessments. The orthodontic tooth movement values were analyzed using three-way ANOVA test. The mean overall premolar movement towards canine in the socket filled with NanoBone[TM] was 1.076mm while it was 1.203mm in the control side. No significant differences were noted regarding the graft material, the time and jaw position. Root resoprtion was evident in the pressure regions of both groups and new bone formation was noted in the defects filled using NanoBone[TM]. It was concluded that NanoBone[TM] has osteoconductive properties with the decreased root resoprtion due to the limited tooth movements. Therefore, the tooth can be moved into the NanoBone[TM] graft material and the graft can be used as a substitution for autogenous bone during orthodontic tooth movements

[Feasibility of recycling mechanical properties of used NiTi orthodontic wires by electromechanical treatment]

The desirable mechanical properties of nickel-titanium alloy wires have prompted many clinicians to recycle these wires. The purpose of this study was to investigate the changes in mechanical properties of nickel-titanium alloy wires after recycling by electromechanical treatment. In this experimental study, round 0.018 inch nickel-titanium wires [American Orthodontics trademark] were used. For purpose of determining the behavior of samples in mouth, the transformation temperatures of alloy were carried by electrical resistance test. The types of nickel-titanium wires were separated into three groups: 1- as received condition [control wires], 2- treated by low electrical current, 3- treated by high electrical current. Mechanical properties changes were observed by tensile testing. One-way analysis of variance and Tukey HSD [SPSS statistical package] was used for purpose of comparison. The results demonstrated significantly greater remained strains after recycling, but plateau stresses and elastic strain energies of the wires were decreased compared with the control wires. Super elastic property of electromechanical treated nickel-titanium wires is decreased following electromechanical treatments

[Effect of the lack of gonadal hormones on the calcium level of tibia bone in rats]

Gonadal hormones have effect on the growth through increasing the osteoblastic activity of bone. They have influence on the calcium metabolism and therefore, are influential on the calcium level of serum and the strength of the bones. The purpose of this study is to examine the effects of gonadal hormones deficiency on the percentage of bone calcium of the tibia in rats. In the present experimental study 50 thirty - day - old Wistar rats comprised the sample. 25 male rats were randomly divided into 2 groups: Experimental group, i.e. orchidectomy ORX, [n=15] and control group, sham- operation, [n=10] and also 25 female rats were divided in the same way into 2 groups: Experimental group, i.e. ovariectomy OVX, [n=15] and control group, sham- operation, [n=10]. Samples were sacrificed 6 months after the surgery i.e. orchidectomies, ovariectomies, and sham operations. Percentage of bone calcium was determined by atomic absorption spectrophotometry. Serum testosterone, progesterone and estradiol levels were measured by ELISA. Serum testosterone level significantly decreased in the ORX group as compared with the male sham- operated group. In this study estradiol level was not changed in OVX group, but despite the significant decrease in progesterone level [p<0.001], no significant differences in all variables were found between the OVX group and female sham- operated group. In the ORX group, body length and weight, were significantly smaller than in the male sham- operated group. No significant difference in bone calcium percentage was found [Student's t-test] between control and experimental groups. In conclusion, it seems that the suppression of gonadal hormones secretion in the growth phase cannot decrease calcium percentage of tibia bone in rats

[Assessment of the correlation between lateral cephalometric and anthropometric indices among the Iranian population]

Anthropometric measurements can be correlated to cephalometric values and have a complementary role to facilitate diagnosis. This Study aimed to determine the correlation between lateral cephalometric and anthropometric indices in the Iranian population. A cross-sectional study using Anthropometric-Cephalometric indices was carried out on 26 subjects with normal occlusion and harmonious facial ratios. Fiberglass meter, wooden ruler and millimetric Anthropometer [Aesculap Inc.] was used as well as hand-made instruments to measure the palm length and angles of the hand. General measurements including height and weight were also taken. For cephalometric measurements, radiographs were taken by an oral and maxillofacial radiologist. Data were subjected to SPSS 9 software. To determine the normal distribution Kolmogorov-Smirnov test was used and P<0.05 was considered significant. Also Spearman and Pearson coefficient correlation was calculated and t-test was performed. In 12 of the 26 cases the correlation coefficient regarding the bizygomatic width [FW] with lower face height [LFH], SE, S-Gn; facial height [FH] with Pog to NB, Nasion-Menton; upper lip vermilion with SE, weight with ANB, Ar-Go; LFH with Ar-Go, forearm length with angle of facial convexity, height with Na-ANS were significant at p<0.01. There was correlation between LFH and FW and Facial Depth that infers three-dimensional proportional facial growth. The forearm length and the facial convexity angle [non-craniofacial anthropometric indices] have a negative co-efficient of correlation. This means that the longer the forearm the straighter the profile. Though there are numerous statistically significant relations between anthropometric and cephalometric indices, in this study these relations were not so clinically momentous in most of the cases

[Correlation of bone resorption induced by orthodontic tooth movement and expression of RANKL in rats]

The product of RANKL gene expression has a fundamental role in bone resorption and activates the chain of osteoclast differentiation from its predecessor cells. Reports of this gene participation and role in physiologic and pathologic bone resorption led to hypothesis that it may play a role in bone resorption induced by orthodontic tooth movement. A closed coil spring [Dentaurum Ispringen, Germany] was fixed by two pieces of ligature wires to mesial side of the maxillary right first molar and anteriorly to both incisors of fifteen 7 week old Wistar male rats to tip the first molars mesially. The maxillary left first molar of each animal used as an internal control group for the contralateral tooth. The animals were sacrificed on the 21St day of the experiment and the tissue from the mesial side of maxillary molars was used for PCR test. Wilcoxon Sign Rank test was used for densitometric analysis of RANKL mRNA on the electrophoresis gel. Statistical analysis showed a significant increase in expression of gene in the experimental group compared to the control one [P<0.002]. Genuineness of the PCR tests was verified by household gene of GAPDH. Based on the data obtained in controlled environment of the study, RANKL expression increased significantly following bone resorption induced by orthodontic tooth movement

[Effect of pamidronate on tooth movement and root resorption in rat]

The purpose of this study is to examine the effect of administration of bisphosphonate; an antiosteoclastic agent i.e. Pamidronate, on the orthodontic tooth movement and root resorption in rats. The present experimental study was conducted on 30 male 8 weeks old Wistar rat. On day zero the orthodontic appliance was installed. Control group received normal saline and for experimental groups, Pamidronate Img/kg, was injected intraperitoneally. After 21 days, rats of control group and experimental were sacrificed and the upper jaws were dissected and the distance between upper 1st and 2nd molars were measured. Under light microscope root resorptive lacunae were calculated by computer software. Student t-test was used for purpose of comparison between groups. There were significant differences between the control [0.562 +/- 0.168 mm] and the experimental group [0.346 +/- 0.197 mm] for orthodontic tooth movements [p<0.01 by paired t-test]. Looking to root resorption no significant differences were observed between the control [0.25 +/- 0.175x10[-2] square millimeter] and the experimental group [0.26 +/- 0.125x10[-2] square millimeter]. According to the present study, Pamidronate can reduce tooth movement and at the same time no increase of the root resorption is observed

[Effect of sexual hormone elimination on the changes of craniofacial dimensions in rats]

It is well - known that sex hormones regulate bone metabolism. Sex steroids increase osteoblasts activities and affect growth, remodeling and bone homeostasis. The aim of this study was to examine the effects of sex hormones deficiency on craniofacial growth in rats. Fifty, thirty-day-old Wistar rats comprised the sample in this experimental study. 25 male rats were divided into 2 groups: Experimental group, ORX, [n=15] and control group, sham-operation, [n=10] and 25 female rats were divided in the same way: Experimental group, OVX, [n=15] and control group, sham-operation, [n=10]. Body length and weight were registered monthly. The rats were sacrificed 6 months after the surgery. Direct millimetric measurements of the skeletodental variables and the tibial length were obtained by using electronic caliper. Serum testosterone, progesterone and estradiol levels were measured by ELISA. One Way ANOVA, Tukey and Student t tests were used to analyze the data. Serum testosterone level significantly decreased in the ORX group as compared with the male sham-operated group. In the ORX group, body length and weight, coronoid height, mandibular length, mandibular arch length, midfacial width, midfacial length, midfacial height, calvarial width, maxillary arch width, premaxillary length, nasal bone height, facial width, basisphenoid bone length and tibia bone length were significantly smaller than in the male control group. Structures showing cartilaginous growth were influenced more than structures showing sutural growth. Estradiol level did not change in OVX group, but despite the significant decrease in progesterone level, no significant differences except weight were found between the OVX group and female control group. In conclusion, it is strongly suggested that the suppression of sex hormones secretion in the growth phase might inhibit craniofacial growth and results in poor craniofaeial development and developing malocclusion

[Effect of mixed chlorhexidine fluoride gel made in Iran on the level of Mutans Streptococci around orthodontic brackets]

Patients with fixed orthodontic appliances often experience an increase in the rate of dental caries. Appling chlorhexidine and fluoride is known to be an effective method to solve this problem since Mutans Streptococci is described as the most important bacteria related to the etiology of dental caries. The aim of this study was to evaluate clinically the application of a chlorhexidine-fluoride gel made in Iran on the level of Mutans Streptococci in plaque adjacent to bonded orthodontic brackets. In this double blind clinical trial 37 patients were selected. The patients were divided into 2 groups: those treated with chlorhexidine-fluoride gel five times with one week interval [group A] and those treated with placebo gel [group B]. The level of Mutans Streptococci in the plaque of canine and second premolar of Maxilla before and after treatment was evaluated and compared by Wilcoxon Signed Rank test. The range of changes in group A was compared with group B by Mann-whitney test. Statistical analysis showed a significant difference between baseline and final colony count results in group A [P<0.0001] but no significant difference in group B and also Mann-Whitney test showed a significant difference between the 2 groups [P<0.0001]. Chlorhexidine-fluoride significantly decreased the level of Mutans Streptococci in plaque around the orthodontic brackets

[ evaluation of the marginal integrity of porcelain fused to base metal crowns after extension of porcelain to the border of the margin]

In PFM restorations, marginal coverage of the metal framework with porcelain, without producing an overcontoured margin is necessary to enhance esthetics. The aim of this study was to evaluate the marginal integrity of a porcelain fused to base metal crown after extension of porcelain to the border of the margin. Thirty brass standard dies were prepared and divided into 3 groups of 10, based on different finishing lines: 90° shoulder, 1.2-mm-wide; 135° slopping shoulder, 1.2-mm-wide; and shoulder, 0.7-mm-wide with a 45° bevel, 0.5 mm-long. For each die a brass cap was fabricated according to the specific finishing line to accommodate a 0.5 mm thickness. Two metal copings were made on each die which were used as test and control samples. The marginal gap of each coping was measured at 4 points under a reflective microscope after casting and oxidation. Porcelain was applied and extended to the border of the margins in the test group and 0.5 mm short of the borders in the control group. Marginal gaps were measured once more at the same points after porcelain firing. Statistical analysis was performed using t-test. The marginal gaps of all copings increased after porcelain firing. Extension of porcelain to the border of the margins did not significantly increase the marginal gaps. These results indicated that porcelain can be extended to the border of the crown's margin without producing a significant increase in the marginal gap

effect of zinc and iron supplementation on the status of iron and zinc in the primary schoolchildren

The micronutrient deficiency is an important health problem around the world. Among the micronutrients, iron and zinc deficiencies are the most common. The aim of this study was to find the effects of iron and zinc supplementation, alone or combined, on iron and zinc status of the primary school children. The study was a randomized double-blind clinical trial in which 81 primary schoolchildren of 11 years old were divided into 3 groups. Group 1 were supplemented with iron [20 mg/d], group 2 with zinc [20 mg/d] and group 3 with iron plus zinc [20 mg/d of each] for 4 months. At the beginning and at the end of this intervention, using cell counter, radioimmunoassay, and atomic absorption, hemoglobin plasma ferritin and serum zinc, the children, were measured. Data was analyzed using ANOVA, paired t test, Wilcoxon and Kruskal-Wallis tests. Our results showed that using either iron or zinc alone and using both of them together significantly increased the serum zinc level to 4.5 +/- 2.1, 4.5 +/- 2.7 and 3.6 +/- micromole per liter, respectively. Among the 3 groups studied, zinc supplementation had the most benefit for the children who suffered from zinc deficiency [p<0.01]. Using iron complementation alone, resulted in an increase in serum ferritin, while using zinc alone, led to a decrease in plasma ferritin [p<0.01]. Both iron and zinc supplementation and the combination of them had no significant impact on blood hemoglobin. Supplementation with either iron or zinc, would improve serum zinc and plasma ferritin

Prevalence of tooth size discrepancies [Bolton analysis] in sagittal malocclusions

To evaluate the prevalence of tooth-size discrepancies among orthodontic patients with sagittal malocclusions by performing Bolton analysis. Two hundred pairs of study models of skeletal Cl I, II, III and crowding were selected. All permanent teeth were present except second and third molars, without any attrition, caries or restorations on their interproximal surfaces. The greatest mesiodistal diameter was measured to the nearest 0.01 mm by means of digimatic calipers. The Bolton's anterior and overall ratios were perfomed on these models to find tooth-size discrepancies. The mean, SD, range, CV and SE were assessed. The four groups were compared by variance analysis. The amount of obtained ratios were compared with Bolton's ratios by T - test, and the difference over 2SD was considered significant. The tooth size discrepancy was more prevalent in crowding group [%14] regarding the overall ratio, and more in cl III group [%28] regarding anterior ratio. The means of Anterior and Overall ratios in the present study [78.21 +/- 2.69, 92.01 +/- 2.45] were larger than Bolton's measurements [77.2 +/- 1.65, 91.3 +/- 1.91] [P<0.0001]. Even though the means of the tooth size ratios of the current study were significanthy different from Bolton's results, the amount of differences were not more than 1.5 mm, hence we can apply the Bolton's ratios for Iranian people. When the Bolton's results were applied to our study, for the Anterior ratio 23% and for the Overall ratio 9% of patients fell outside of 2SD and tooth-size discrepancies. Regarding tooth- size discrepancies specially in crowding and crossbite cases, which are not detectable by inspection alone, it is suggested that Bolton's tooth size analysis be performed before starting the orthodontic treatment