A population-based survey on interarch malocclusion and background determinants

Background

Genetics, environment, and ethnic factors are major contributors to the prevalence and variations of malocclusion.

Aim

The aim of study was to determine the prevalence of interarch problems in school-aged children, 9 - 11 years, living in Tehran; and to describe the role of ethnicity, education, and economic status on them.

Methods

The present data were part of the Comprehensive Evaluation of Skeleto-Dental Anomalies (CESDA) study conducted in 2015 among children living in Tehran, Iran. Cluster random sampling was applied among 19 districts of Tehran. A total of 38 schools were selected, and out of 1585 participants, the data of 1429 children were collected (response rate = 90%). The Chi-square test and binary logistic regression analysis were used for statistical analyses.

Results

Of all participants, 758 were boys and 671 were girls. The mean age was 121 ± 8 months. The most significant background determinants associated with molar relationship were ethnicity and place of residence. Class I right molar relationship was seen in 57.9% of the children and was generally more frequent in boys. Normal overjet was observed in 47.1%; 41.5% had an increased overjet, 16.2% had an anteroposterior cross-bite, and 11.8% had a lateral cross-bite. Midline discrepancy was seen among 61.1% of the children. Ideal anteroposterior, vertical, and horizontal relationship were observed in 31%, 53%, and 34% of the children, respectively. Only 10% of the children aged 9 - 11 years old had an ideal interarch relationship. Gender and place of residence had persistently significant association with having an ideal anteroposterior, vertical, horizontal, and interarch relationships (P < 0.002) in all four binary logistic regression models.

Conclusions

The majority of the children aged 9 - 11 years old have at least one interarch problem, although it is commonly preventable.

Relevance for Patients

Early detection of children's orthodontic problems may help with effective prevention of further advanced anomalies.

Combining Circumvestibular Corticotomy with Maxillary Protraction as a Conservative Approach to Treatment in an Adolescent with Maxillary Deficiency: A Case Report with Long Term Follow-up

Maxillary protraction with a face mask is an effective treatment for class III children with maxillary hypoplasia. However, in late adolescence, orthopedic approaches are not very effective for treatment of maxillary deficiency. The aim of this study was to report a minimally invasive technique to orthopedically treat a 16-year-old female adolescent with mild to moderate maxillary deficiency, before the cessation of growth. A circumvestibular corticotomy technique was performed followed by a regimen of rapid maxillary expansion and application of heavy extra-oral forces. After termination of the orthopedic and orthodontic phases, the patient was monitored for ten years. The dental and skeletal results immediately after treatment were compared with the results ten years after termination of treatment. A noticeable anterior displacement of “A” point was observed after the orthopedic phase and this remained unchanged for ten years.

Cardioprotection using strain-guided management of potentially cardiotoxic cancer therapy: 1 year results of the SUCCOUR trial

Background

Conventional criteria for diagnosis of chemotherapy-related cardiac dysfunction (CTRCD) are dependent on the recognition of heart failure (HF) symptoms and/or changes in LVEF. However, the low sensitivity of EF for minor changes in LV function may delay initiation of cardio-protective therapy (CPT). Global longitudinal strain (GLS) is a robust and sensitive marker of LV dysfunction (LVD), but existing observational data are insufficient to justify changing the diagnostic criteria for CTRCD.

Purpose

To identify whether GLS guidance of CPT would improve cardiac function of at risk patients undergoing potentially cardiotoxic chemotherapy, compared with usual care.

Methods

In this international multicenter prospective randomized controlled trial, 331 pts from 23 international sites taking anthracyclines with another risk factor for HF were randomly allocated into 166 undergoing GLS-guided (CPT for &gt;12% relative reduction in GLS using Echopac software) and 165 EF-guided (CPT for &gt;10% absolute reduction of EF). Pts were followed over 1 year for the primary end-point (ΔEF) with 3D echo (3DE); 2D echo (2DE) was used when 3D images were unsuitable for measurement. Development of CTRCD (EF reduction of 10% to &lt;55%) was a secondary endpoint.

Results

Of 331 randomized patients, 24 withdrew before follow-up imaging was performed (2 died, and rest withdrew or were lost to follow-up). Among 307 patients (age 54±12 years, 94% women) with follow-up 1.0±0.2 years, 277 had breast cancer, 30 had lymphoma/leukemia. HF risk factors were prevalent: 89 (29%) had hypertension and 39 (13%) had diabetes mellitus. The most common chemotherapy regimen during this study was the combination of anthracycline and trastuzumab. The baseline 3D LVEF was 61±5%, and GLS was −20.8±3.2%. At 1 year follow-up, 31 (10%) met CTRCD and was reduced in the GLS-guided arm (Table 1), although new LV dysfunction (EF&lt;55%) and change of EF were not different.

Conclusion

In this international multicentre trial, the incidence of CTRCD was reduced by strain-guided cardioprotection. Although the final EF and the number of pts developing EF &lt;55% was not altered by strain-guided therapy, this reduces meaningful reduction of EF to the abnormal range. The results support the use of GLS in surveillance for CTRCD.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): General Electric Medical Systems

A numerical-experimental study on thermal evaluation of orthodontic tooth movement during initial phase of treatment

The most desired target of orthodontic treatment is tooth movement as a result of application of efficient force system. In this study, effect of tooth loading is studied on temperature profile around the tooth at early stages of treatment. The basis of temperature variation is increase of cell number and activities in periodontium as a result of compression and tension of this layer. Highest cellular activities occur in the beginning of loading procedure and aim to reduce mechanical stress in the periodontium which finally ends up with orthodontic tooth movement during couple of years. To find out the correlation between temperature variation and the applied force, in vivo experiments are conducted on ten rats and temperature is measured in specific time periods. It is observed that temperature is higher in direction of the net force about 0.3℃. Next, numerical finite element analysis is carried out on the rat tooth model. Mechanical stress results show that regions with compressive stress have rather high temperature in the experiments. Mechanical stress on periodontium-bone interface is multiplied by a coefficient to simulate cellular activities on this boundary as a heat source and thermal analysis is carried out to obtain temperature profile. The thermo-mechanical coefficient is identified for each rat by imposing the experimental temperatures on numerical outputs. For assessment of a treatment efficiency and deduction of the applied force, temperatures could be measured experimentally and compared with the corresponding numerical analysis temperature result obtained by employing the thermo-mechanical coefficient found earlier for each rat.

Initial stage of atomic layer deposition of 2D-MoS2 on a SiO2 surface: a DFT study

In this study, we investigate the reactions involving Atomic Layer Deposition (ALD) of 2D-MoS2 from the heteroleptic precursor Mo(NMe2)2(NtBu)2 and H2S as the co-reagent on a SiO2(0001) surface by means of density functional theory (DFT). All dominant reaction pathways from the early stage of adsorption of each ALD reagent to the formation of bulk-like Mo and S at the surface are identified. In the metal pulse, proton transfer from terminal OH groups on the SiO2 to the physisorbed metal precursor increases the Lewis acidity of Mo and Lewis basicity of O, which gives rise to the chemical adsorption of the metal precursor. Proton transfer from the surface to the dimethylamido ligands leads to the formation and desorption of dimethylamine. In contrast, the formation and desorption of tert-butylamine is not energetically favorable. The tert-butylimido ligand can only be partially protonated in the metal pulse. In the sulphur pulse, co-adsorption and dissociation of H2S molecules give rise to the formation and desorption of tert-butylamine. Through the calculated activation energies, the cooperation between H2S molecules ('cooperative' mechanism) is shown to have a profound influence on the formation and desorption of tert-butylamine, which are crucial steps in the initial ALD deposition of 2D-MoS2 on SiO2. The cyclic ALD reactions give rise to the formation of a buffer layer which might have important consequences for the electrical and optical properties on the 2D layer formed in the subsequent homodeposition.

A novel approach for early evaluation of orthodontic process by a numerical thermomechanical analysis

The main objective of this paper is to propose a novel method that provides an opportunity to evaluate an orthodontic process at early phase of the treatment. This was accomplished by finding out a correlation between the applied orthodontic force and thermal variations in the tooth structure. To this end, geometry of the human tooth surrounded by the connective soft tissue called the periodontal ligament and the bone was constructed by employing dental CT scan images of a specific case. The periodontal ligament was modeled by finite strain viscoelastic model through a nonlinear stress-strain relation (hyperelasticity) and nonlinear stress-time relation (viscoelasticity). The tooth structure was loaded by a lateral force with 15 different quantities applied to 20 different locations, along the midedge of the tooth crown. The resultant compressive stress in the periodontal ligament was considered as the cause of elevated cell activity that was modeled by a transient heat flux in the thermal analysis. The heat flux value was estimated by conducting an experiment on a pair of rats. The numerical results showed that by applying an orthodontic force to the tooth structure, a significant temperature rise was observed. By measuring the temperature rise, the orthodontic process can be evaluated.

The effect of caffeine on orthodontic tooth movement in rats

Objective(s):

to determine the effect of different doses of caffeine on orthodontic tooth movement (OTM) in rats.

Materials and Methods:

Forty male 250-300 g Sprague-Dawley rats were randomly divided into four groups of ten animals each and received 0 (control), 1 g/l, 2 g/l and 3 g/l caffeine in tap water for 3 days. Orthodontic appliances were ligated between the maxillary first molars and incisors on the 4th day of the study period. All rats were sacrificed after 2 weeks of treatment after which OTM was measured. Hematoxylin/eosin-stained sections of the molars were prepared and the mesial roots were examined for resorption-lacunae depth and osteoclast number. ANOVA was used for statistical analysis (P<0.05).

Results:

A significant decrease in OTM was observed only in the 2 g/l (P=0.043) and 3 g/l (P<0.01) caffeine-receiving rats compared to the control animals. Osteoclast counts and resorption-lacunae depths demonstrated significant differences between each of the caffeine groups and control rats (P<0.05). None of the variables showed significant differences between the caffeine groups (P>0.05).

Conclusion:

According to our findings, one of the effects of caffeine consumption during orthodontic treatment in rats was decreased root resorption. Additionally, concentrations of 2 g/l and 3 g/l inhibited OTM which seems to be due to its influence on osteoclast numbers.

Genetic diversity, host range, and distribution of tomato yellow leaf curl virus in Iran

Tomato yellow leaf curl virus (TYLCV) is considered one of the most important tomato pathogens in tropical and subtropical regions including Iran. During the years 2007 to 2009, a total number of 510 symptomatic and asymptomatic vegetable, ornamental and weed samples were collected from fields and greenhouses in ten provinces of Iran. Symptoms included stunting, yellowing, leaf curl and flower senescence. PCR with specific primers showed TYLCV infection in 184 samples (36%) such as cucumber, pepper, tomato and several weeds from seven provinces. Based on the geographical origin, host range and symptoms, twenty three representative isolates were selected for phylogenetic analysis. An amplicon with a size about 608 base pair (bp) comprising partial sequence of the coat (CP) and movement protein (MP) coding regions of the viral genome was sequenced and compared with the corresponding selected sequences available in GenBank for Iran and worldwide. Phylogenetic analyses on the basis of the nucleotide sequences indicated two geographically separated clades. Isolates collected from Hormozgan, Khuzestan and Kerman provinces were grouped together with other Iranian isolates including TYLCV-Ir2, TYLCV-Kahnooj, and an isolate from Oman. It was also revealed that isolates collected from Boushehr, Fars, Tehran, and Isfahan placed close to the Iranian isolate TYLCV-Abadeh and isolates from Israel and Egypt. No correlation was found between the genetic variation and the host species, but selected Iranian isolates were grouped on the basis of the geographical origins. Results of this study indicated a high genetic diversity among Iranian TYLCV isolates.

Pantoprazole, a proton pump inhibitor, increases orthodontic tooth movement in rats

OBJECTIVES

Pantoprazole, is a proton pump inhibitor (PPI) prescribed for the treatment of upper gastrointestinal disorders, which in high doses has been suggested to decrease calcium absorption leading to hypocalcaemia and therefore osteoporosis. The aim of this study was to assess whether pantoprazol, could alter the rate of orthodontic tooth movement (OTM) in rats.

MATERIALS AND METHODS

A time course study was established using 72 rats which were divided into six groups of 12 samples each (four: vehicle; eight: pantoprazole + vehicle). Pantoprazole at a dose of 200 mg/kg suspended in carboxymethyl cellulose (0.25 percent) was administered by a gastric tube. The upper incisors and first molars were ligated by a 5 mm nickel-titanium closed-coil spring to deliver an initial force of 60 g. Animals were euthanized two weeks after orthodontic treatment followed by assessment of tooth movement and histomorphometric evaluation of the detached maxillae. Lateral skull radiographs were obtained once a week, starting from the first day to the 6(th) week of the study. OTM and bone density data were analyzed using independent sample t-test and repeated measures ANOVA.

RESULTS

No significant changes in OTM measurements and optical density were observed in vehicle-receiving animals during the study (P=0.994). OTM was significantly increased after six weeks pantoprazole therapy which continued until the 7(th) week of the experiment (P=0.007). Optical density significantly increased in the pantoprazole-treated rats after six weeks.

CONCLUSION

Long term PPI therapy at high doses could lead to osteoporosis and enhanced OTM.

Assessing medical students' communication skills by the use of standardized patients: emphasizing standardized patients' quality assurance

OBJECTIVE

The objective structured examination is one of the most valid, reliable, and effective tools for assessing clinical and communication skills, often by use of standard patients (SPs). SPs can also be assessors of those skills. One of the crucial areas when utilizing SP-based assessment is the quality and consistency assurance of their portrayal of the case and their ability to fill in checklists in an adequate way. The aim of this study was to assess the validity and reliability of SPs' ability to assess students' communication skill via a Calgary-Cambridge checklist.

METHOD

This cross-sectional and correlational study was conducted at the Tehran University of Medical Science. We first analyzed validity; the criterion validity of the SPs' filling in the checklists was assessed through determining the correlation between the SPs' completed checklists and the checklists filled in by three physician raters individually and then reproducibility: it was assessed by a test-retest approach inter-rater reliability.

RESULT

The mean correlation for assessing the validity of SPs' completed checklists by individual SPs was 0.81. The inter-rater reliability was calculated by kappa coefficient, and the total correlation among the three raters was 0.85. The reliability of the test-retest approach showed no significant differences between the test and re-test results.

CONCLUSION

The increased number of medical students and different faculties' responsibilities such as doing educational, research, and health services duties assessing medical student communication skills is a complex issue. The results of our study showed that trained SPs can be used as a valid tool to assess medical students' communication skills, which is also more cost effective and reduces work load of medical faculties.

INFLUENCE OF FIBER TYPE AND COATING ON THE COMPOSITE PROPERTIES OF EPDM COMPOUNDS REINFORCED WITH SHORT ARAMID FIBERS

There is a renewed interest in the application of short aramid fibers in elastomers because of the considerable improvement in mechanical and dynamic properties of the corresponding rubber composites. Possible applications of short aramid fiber–reinforced elastomers are tires, dynamically loaded rubber seals, diaphragms, engine mounts, transmission belts, conveyer belts, and hoses. Our studies are related to the investigation of dispersion, length distribution, and the fiber–matrix interaction of two types of short aramid fibers, standard coated and resorcinol formaldehyde latex (RFL) coated, in ethylene–propylene–diene rubber (EPDM). Because the detection of the polymer fiber morphology in rubber compounds is hampered in the presence of carbon black, which is typically used in industrial elastomer compounds, fiber length, fiber length distribution, and dispersion are investigated in corresponding carbon black–free model compounds. Optical methods, scanning electron microscopy, and tensile testing are employed to explore the short aramid fiber–reinforced elastomer composites. The effects of morphology and fiber–matrix interaction on the mechanical properties of composites are discussed. Regarding fiber type, it is shown that co-poly-(paraphenylene/3,4′-oxydiphenylene terephthalamide) (PP/ODPTA) fibers end up with a higher final length than does poly(para-phenylene terephtalamide) (PPTA), which results in considerably higher mechanical properties of corresponding rubber compounds. For each fiber type, the higher final length as a result of RFL coating and the interaction with the rubber matrix are the key factors that overcome even the negative effect of poorer dispersion of RFL-coated fibers. The differences between the short aramid fibers and aramid cords regarding the RFL coating are also discussed.

Periodontal parameters following orthodontic treatment in patients with aggressive periodontitis: A before-after clinical study

BACKGROUND

The success of combined periodontal and orthodontic approach in the treatment of aggressive periodontitis patients with the pathologic extruded anterior teeth is a main concern and stability of the treatment results is an important factor to evaluate the treatment. The present study investigated the periodontal parameters at the end of the orthodontic treatment in patients with the aggressive periodontitis.

MATERIALS AND METHODS

Eight patients with an aggressive periodontal disease, extruded maxillary incisors, infrabony defects and probing depth of ≥5 mm were enrolled in this clinical trial (before, after). After periodontal therapy, orthodontic treatment was carried out for intrusion and alignment of teeth. Plaque index (PI), probing pocket depth (PPD), distance between incisal edge and interdental papilla, root length (RL), and defect dimensions (depth and width) were examined at the end of treatment and three as well as 6 months afterward. The data were subjected to repeated measure ANOVA test. P < 0.05 was considered as significant.

RESULTS

There was statistically significant decrease in PPD, PI, and depth of the defects during T0, T3 and T6 (P < 0.05). No significant differences were observed in the RL and distance between incisal edge and interdental papilla (P = 0.95). Furthermore, width of the defects demonstrated significant decrease up to T3 (P = 0.042) while no significant changes from 3 months to 6 months were noted (P = 0.59).

CONCLUSION

The results showed that combined periodontal and orthodontic approach would be a successful treatment with acceptable stability in the case of regular follow-up visits and controlled oral hygiene habits.

Spectral analysis of word-initial alveolar and velar plosives produced by Iranian children with cleft lip and palate

Spectral moment analysis (SMA) was used to describe voiceless alveolar and velar stop-plosive production in Persian-speaking children with repaired cleft lip and palate (CLP). Participants included 11 children with bilateral CLP who were undergoing maxillary expansion and 20 children without any type of orofacial clefts. Four of the children with CLP also exhibited backed (palatal) placement for alveolar stops. All children produced consonant-vowel-consonant nonsense words that targeted the plosives /t/ and /k/. SMA revealed that children with CLP had significantly reduced first spectral moment of /t/ and /t/-/k/ difference. Children with CLP who produced palatal stops for alveolar targets also had lower but non-significant first spectral moments for /t/ as compared with children with CLP who did not produce palatal stops. The results are consistent with previously reported findings for English-speaking children with repaired CLP and further suggest that maxillary arch constriction may be a contributing factor for (a) reduced spectral distinction of alveolar targets and/or (b) palatal substitutions for alveolar targets.

Association of hypertriglyceridaemia with pre-eclampsia, preterm birth, gestational diabetes and uterine artery pulsatility index

BACKGROUND

We aimed to determine whether high plasma triglyceride levels in the second trimester of pregnancy are associated with adverse pregnancy outcomes including preterm birth, gestational diabetes mellitus, pre-eclampsia and high uterine artery pulsatility index.

METHODS

This prospective cohort study was done between 2008 and 2010. Plasma levels of low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglyceride were measured after 8 hours of overnight fasting. We compared the outcomes of 45 pregnant women who had high triglyceride levels (>195 mg/dl) with 135 pregnant women with triglyceride levels <195 mg/dl. The main outcome measures were the incidence of preterm birth, gestational diabetes, pre-eclampsia and uterine artery pulsatility index.

RESULTS

Eight women with high triglyceride levels had preeclampsia (17.8% v. 3.7% in the control group, p<0.004), preterm birth occurred in 24.4% and 5.9% in the high triglyceride group and the control group, respectively (OR 5.1,95% CI 1.9-13.8, p<0.0001). The incidence of gestational diabetes in the high triglyceride group was significantly higher than that in the control group. There was no difference in uterine artery Doppler ultrasound between the two groups.

CONCLUSION

There is a positive relation between hypertriglyceridaemia and pre-eclampsia, preterm birth and gestational diabetes.

Copy number changes on the X chromosome in women with and without highly skewed X-chromosome inactivation

AIM

To test the hypothesis that microdeletions or microduplications below the resolution of a standard karyotype may be a significant cause of highly skewed X-inactivation (HSXI) in women without a cytogenetically detected X-chromosome anomaly.

METHODS

Cases were women with HSXI, defined as ≥85% of cells in a blood sample with the same active allele at the HUMARA locus. The skewing in controls ranged from 50 to <75%. We performed an SNP microarray analysis using the Affymetrix 6.0 platform for 45 cases and 45 controls.

RESULTS

Cases and controls did not differ in the frequency of X-chromosome copy number changes ≥100 kb or in the frequency of copy number changes that contained genes. However, one woman with HSXI >90% in blood and left and right buccal smears had a 5.5-Mb deletion in Xp22.2p22.1. This deletion could affect the viability of male conceptions and may have led to the dysmorphology found in female carriers.

CONCLUSION

HSXI in a blood sample is rarely due to X-chromosome copy number changes detectable by microarray.

Comparison of oral-health-related quality of life during treatment with headgear and functional appliances

BACKGROUND

Functional and headgear are two well-known approaches in the treatment of skeletal class II malocclusion in preadolescent children. Assessment of psycho-social impacts of wearing devices during the treatment period is central to enhancing the quality of healthcare services.

AIM

This study aimed to compare oral-health-related quality of life in two groups consisting of children wearing headgear or functional appliances. We also compared these groups with a non-malocclusion group.

DESIGN

The study population consisted of 187, 11- to 14-year-old children in three groups of functional (n = 67), headgear (n = 67) and non-malocclusion (n = 53). Children were asked to complete the translated version of the short form of the Child Perceptions Questionnaire. Total scores and subscale scores of the three clinical groups were compared through ANOVA.

RESULTS

There was no significant difference in mean total scale score and subscale scores between functional and headgear groups (P > 0.05). Significant differences were found in both mean total and subscale scores between the malocclusion and non-malocclusion groups (P < 0.001) except oral symptoms subscale (P > 0.05).

CONCLUSIONS

The results of this study reveal that functional and headgear appliances do not differ in terms of impact on daily life during the treatment. Moreover, both groups have poorer OHQoL compared to malocclusion group.

FACTORS INFLUENCING REINFORCEMENT OF NR AND EPDM RUBBERS WITH SHORT ARAMID FIBERS

Among short fiber reinforced composites, those with rubbery matrices have gained great importance due to the advantages they have in processing and low cost, coupled with high strength. These composites combine the elastic behavior of rubbers with strength and stiffness of fibers. Aramid fibers have been chosen because of their significantly higher modulus and strength, compared to other commercial fibers. Compounds based on NR and EPDM are prepared. Short aramid fibers with different kinds of surface treatments, standard finish, and resorcinol formaldehyde latex (RFL)-coating result in different rubber–fiber interfaces. The reinforcing effect of these short aramid fibers is characterized by mechanical and viscoelastic experiments, and by studying the fracture surfaces with electron microscopy techniques. Related to the fiber coating and rubber curing system, sulfur- or peroxide-based, different reinforcement mechanisms are observed, where the combination of peroxide-cured EPDM with RFL-treated fibers is the only case showing clear signs of chemical adhesion. In all other combinations there are only indications of mechanical interactions of the fibers with the rubber matrices, due to bending/buckling of fibers, dog-bone shaped fiber ends, and surface roughness due to the RFL-coating.

Foley catheter entrapment resulting from the formation of a true knot in a female infant: sonographic findings

One of the rarest complications of bladder Foley catheter insertion is knotting of the catheter. We present a case of Foley entrapment secondary to formation of a true knot at the proximal end of the catheter in a 6-month-old female infant who was referred to our center for voiding cystourethrograthy. Sonography of the bladder revealed the knotted catheter in the urinary bladder.

Effect of intralesional verapamil for treatment of Peyronie's disease: a randomized single-blind, placebo-controlled study

PURPOSE

We aimed to assess the effect of intralesional verapamil on the treatment of Peyronie's disease.

MATERIALS AND METHODS

This randomized study involved 80 patients. First, they were divided into two groups. The first group (case: 40 patients) received intralesional verapamil and the second group (control: 40 patients) local saline injection. They were followed about 24 weeks and evaluated for the size of plaques, plaque softening, reduction of pain and amelioration of penile deformity and erectile dysfunction (estimated by the International Index of Erectile Function) before and after treatment.

RESULTS

Reduction of plaque size was seen in 17.5% of the case group and 12.8% of the control group (P: 0.755). Pain was reduced in 30% of the case group and 28.2% of the control group (P: 0.99). Curvature was decreased in 17.5% of the case group and 23.1% the control group (P: 0.586). Plaque softening was seen in 30% of the case group compared with 25.6% improvement in the control group (P: 0.803). Also we found 5% and 2.6% improvement in sexual dysfunction in the case and control groups, respectively. (P: 0.985).

CONCLUSION

Although in some studies verapamil has been found to be effective in the treatment of Peyronie's disease, we did not find any improvement in comparison with the control group. Furthermore, larger scale studies are warranted to assess the effect of this drug on the treatment of Peyronie's disease.

Effects on readiness to change of an educational intervention on depressive disorders for general physicians in primary care based on a modified Prochaska model--a randomized controlled study

BACKGROUND

The Prochaska model of readiness to change has been proposed to be used in educational interventions to improve medical care.

OBJECTIVE

To evaluate the impact on readiness to change of an educational intervention on management of depressive disorders based on a modified version of the Prochaska model in comparison with a standard programme of continuing medical education (CME).

METHODS

This is a randomized controlled trial within primary care practices in southern Tehran, Iran. The participants included 192 general physicians working in primary care (GPs) were recruited after random selection and randomized to intervention (96) and control (96). Intervention consisted of interactive, learner-centred educational methods in large and small group settings depending on the GPs' stages of readiness to change. Change in stage of readiness to change measured by the modified version of the Prochaska questionnaire was the

RESULTS

The final number of participants was 78 (81%) in the intervention arm and 81 (84%) in the control arm. Significantly (P < 0.01), more GPs (57/96 = 59% versus 12/96 = 12%) in the intervention group changed to higher stages of readiness to change. The intervention effect was 46% points (P < 0.001) and 50% points (P < 0.001) in the large and small group setting, respectively.

CONCLUSIONS

Educational formats that suit different stages of learning can support primary care doctors to reach higher stages of behavioural change in the topic of depressive disorders. Our findings have practical implications for conducting CME programmes in Iran and are possibly also applicable in other parts of the world.

Densitometric evaluation of skull and jaw bones after administration of thyroid hormones in rats

OBJECTIVES

An investigation was performed by use of optical densitometry to observe the effects of different doses of thyroid hormone on bone density of skull and jaw bones and to evaluate the relationship between T3, T4, thyroid stimulating hormone (TSH) serum levels and bone density.

METHODS

40 Sprague-Dawley rats were randomly divided into four groups with 10 rats in each (a control group that received 10 ml kg(-1) i.p. per day normal saline and three levothyroxine groups that received 5, 10, or 20 microg kg(-1) i.p. per day levothyroxine, respectively). Radiographs were taken of their skulls on days 3 and 16. At the end of the experimental period blood was drawn by intracardiac puncture and serum was analysed for thyroid hormones (T3 and T4) and TSH level. After that, optical density measurements were made on the radiographs of four selected points on the skull and jaw with a digital densitometer. Density measurements were analysed using the student's t-test, one way analysis of variance, Spearman correlation analysis and regression analysis.

RESULTS

Levothyroxine administration reduced bone density (P < or = 0.05) and increasing the dose of thyroid hormone produced a significant decrease of bone density (P < or = 0.05). The mandible was more susceptible to density changes compared with hard palate, skull and alveolar bone (P < or = 0.05).

CONCLUSIONS

Radiographs of the mandible can be utilized to characterize loss of bone density elsewhere. In addition this investigation indicated that optical densitometry is an inexpensive and low risk method for studying bone density.

The role of opioid systems on orthodontic tooth movement in cholestatic rats

Endogenous opioids have been reported to accumulate in the plasma of cholestatic subjects. Another report showed that human osteoblast-like cells, MG-63, express 3 types of opioid receptors. In our laboratory we noticed that orthodontic tooth movement (OTM) is enhanced in cholestatic rats. Therefore, we suggest a possible role of opioid systems in bone remodeling and raising the rate of OTM in cholestatic conditions. To investigate this hypothesis, rat models were established and divided into 5 study groups. An orthodontic appliance, consisting of a 5 mm nickel-titanium closed coil spring, was ligated between the maxillary right incisor and first molar of each rat to deliver an initial force of 60 g. The bile duct ligated (BDL) group underwent a bile duct ligation operation and received orthodontic appliance 7 days after surgery. Another group underwent a sham operation and orthodontic appliances were inserted just as in the BDL group protocol. Surgery was performed the BDL + naltrexone group and orthodontic appliances were inserted 7 days after surgery. This group received daily subcutaneous injections of naltrexone HCI (an opioid antagonist) at 20 mg/kg at 24-hour intervals from the day of force application until the end of the study period. Another group, the naltrexone group, received naltrexone injections like the BDL + naltrexone group. A fifth control group neither underwent surgery nor received injections. Orthodontic tooth movement was measured 14 days after appliance insertion. The bile duct ligated group showed significantly increased OTM compared to all other study groups (P < .001). The difference between the OTM in the BDL + naltrexone and control groups was insignificant. This study suggests a role for opioid systems in OTM in cholestasis conditions.

The role of nitric oxide in orthodontic tooth movement in rats

Nitric oxide (NO) is involved in second messenger formation, osteoblast and osteoclast function, and pulpal blood flow. This raises the question of whether or not altered NO production interferes with orthodontic tooth movement (OTM) by influencing the bone remodeling cycle. To investigate the role of NO in OTM, a rat model was established and 48 rats were divided into four study groups of 12 rats each. A 5 mm nickel-titanium closed-coil spring was ligated between the right maxillary incisor and first molar of each rat to deliver an initial force of 60 g. A saline group received subperiosteal injections of normal saline (50 microL/kg), an L-arginine (L-arg) group received L-arginine (NO precursor) injections (200 mg/kg), and a, L-NAME group received N(G)-nitro-L-arginine methyl ester (nitric oxide synthase inhibitor)(10 mg/kg) injections. All injections were given in the upper right first molar mucosa from the first through the 11th day of force application at 48-hour intervals. A control group received no injections. Tooth movement measurements were done at the time of injections. Animals were sacrificed 13 days after appliance insertion and final OTMs were measured at the time of sacrifice. From the third day till the end of the experiment, the L-arg group showed a significant increase in tooth movements, whereas the L-NAME group showed a significant decrease in tooth movements compared to the control and saline group (P < .001). Histopathologic studies revealed that the number of osteoclasts was significantly higher in the L-arg group smears, while the number of osteoclasts in the L-NAME group was significantly lower as compared to the control group (P < .001). Scanning electron microscope analysis showed that the force-induced root resorption in the L-arg group was less than the control group. This study suggests a role for NO in the bone remodeling cycle.

The effect of chronic renal insufficiency on orthodontic tooth movement in rats

The purpose of this study was to determine the effects of impaired renal function on the amount of orthodontic tooth movement (OTM) in a rat model of renal insufficiency (RI). The animals were divided into three groups: a control unoperated group in which only OTM was done, a sham-operated group, and an RI group. OTM was done two weeks after performance of the sham operation or the surgery to induce RI. Renal failure was induced by electrocoagulation of one kidney cortex followed by contralateral nephrectomy. A fixed orthodontic appliance consisting of a 5 mm length of nickel-titanium closed-coil spring was ligated between the maxillary right incisor and first molar to deliver an initial mesial force of 60 g. Four weeks after RI induction, the amount of tooth movement was estimated by measuring the space created between the first and second molars on a stone cast. Bone density was measured by optical densitometry on radiographs and serum parathyroid hormone (PTH) was measured with a radioimmunoassay method. The results showed that induction of RI significantly increased both OTM (P < .05) and PTH levels (P < .01), although there was no significant difference in bone density by optical densitometry between the unoperated, sham-operated, and RI groups four weeks after RI induction. The results suggest that an increase of bone-remodeling activities, as evident from a significantly higher level of PTH, may be responsible for increase in tooth movement.

Testosterone receptor blockade restores cellular immunity in male mice after burn injury

Males are known to have increased risk for septic complications after traumatic injury, which appears to be mediated by the inhibitory effects of testosterone on immune function. The role of testosterone in immunity after burn injury, however, remains unclear. Herein, we examined the effects of a testosterone receptor antagonist, flutamide, on delayed type hypersensitivity response (DTH), splenocyte proliferation, interleukin (IL)-2 secretion, and IL-2 receptor (IL-2R) expression in male BALB/c mice subjected to a 15% total body surface area burn or sham injury. Burn- or sham-injured mice were given flutamide s.c. at 30 min and 24 h after injury. At 48 h, burn injury caused a 48% (P<0.001) decrease in DTH response; however, mice that received flutamide treatment did not demonstrate significant suppression of DTH. Likewise, splenocyte proliferation and IL-2 production were depressed in burned animals in comparison with sham-injured controls, and flutamide treatment resulted in a partial restoration of these responses. In vitro studies indicated that splenocytes from sham- and burn-injured mice were equally sensitive to the suppressive effects of 5alpha-dihydrotestosterone in regard to proliferation and IL-2 production. Further evaluation revealed a decrease in IL-2R expression on splenocytes from burned mice and a partial restoration of this expression with flutamide treatment. Thus blocking testosterone receptor activation improves the cellular immunity in thermally injured mice, possibly through restoration of IL-2 production and IL-2R expression. It remains to be determined whether the effects of testosterone in this injury model are direct or indirect.

The effect of thyroid hormone on orthodontic tooth movement in rats

The major goals of this study were to determine the effects of different doses of thyroxin on the rate of orthodontic tooth movement and the force-induced root resorption. In this study fifty male Sprague--Dawley rats were divided into five groups: a normal group with no intervention; a control group in which appliances were placed and 10 ml/kg i.p./day normal saline was injected; and three thyroxin groups in which appliances were placed and 5, 10 and 20/microgram/kg i.p./day L-thyroxin were administered, respectively. A fixed orthodontic appliance consisting of a 5 mm closed-coil spring was ligated between the maxillary incisor and maxillary first molar to deliver an initial force of 60 gm. The results showed that administration of 20/microgram/kg i.p./day L-thyroxin significantly increased the amount of orthodontic tooth movement (p < 0.001). The extent of root resorption as seen from scanning electron micrographs decreased with thyroxin administration.