Comparative study of changes in the airway dimensions following the treatment of Class II malocclusion patients with the twin-block and Seifi appliances

BACKGROUND

Functional appliances are frequently used to stimulate mandibular growth in cases of Class II malocclusion with mandibular deficiency. Many studies have reported improved pharyngeal airway passage (PAP) dimensions following functional appliance therapy in children.

OBJECTIVES

The present study aimed to assess changes in the airway dimensions following the treatment of Class II malocclusion patients with the twin-block and Seifi appliances.

MATERIAL AND METHODS

Lateral cephalograms of 37 patients with Class II malocclusion and mandibular deficiency treated with the twin-block appliance (n = 20) or the Seifi appliance (n = 17) were assessed in this before-and-after study. The preoperative and postoperative lateral cephalograms were compared to determine changes in the airway dimensions at the level of the palatal plane (PP), the occlusal plane (OP) and the 2nd-4th cervical vertebrae (C2-C4) in the 2 groups. The results were analyzed with the t test and the one-way analysis of covariance (ANCOVA).

RESULTS

After treatment, significant changes occurred in the point A-nasion-point B (ANB) and sellanasion-point B (SNB) skeletal cephalometric indices in the twin-block appliance group, and in ANB, SNB and incisor-mandibular plane angle (IMPA) in the Seifi appliance group. The airway dimensions at the level of PP, OP and the 3rd cervical vertebra (C3) significantly increased postoperatively as compared to the baseline in the twin-block appliance group (p < 0.05). The increases in the airway dimensions at the level of PP and C3 in the twin-block appliance group were significantly greater than in the Seifi appliance group (p < 0.05).

CONCLUSIONS

The treatment of Class II Division I malocclusion with the twin-block appliance significantly increased the airway dimensions at the level of PP, OP and C3, whereas the Seifi appliance did not cause any significant changes in the airway dimensions.

Evaluation of shear bond strength and enamel remineralizing effect of experimental orthodontic composite containing nano-hydroxyapatite: An in vitro study

OBJECTIVE

The purpose of this study was to prepare an orthodontic composite containing hydroxyapatite nanoparticles to prevent demineralization and create a suitable environment for mineral deposition around orthodontic brackets, and to investigate the mechanical and remineralizing properties of the experimental adhesive composite.

METHODS

Experimental orthodontic composite were formulated using varying percentages of nano-hydroxyapatite particles. Assessments were based on four groups: a control group (3M™ Transbond™ XT) and experimental composites containing 2% (HA2), 5% (HA5) and 10% (HA10) hydroxyapatite. Vickers Microhardness test was performed to investigate the remineralizing effect in 3 stages: initial stage, after demineralization and after 4 weeks of exposure to artificial saliva. Scanning electron microscopy with energy dispersive X-ray spectroscopy analyser (SEM/EDAX) was used to evaluate hydroxyapatite precipitation and elemental composition of enamel surface. Shear Bond Strength tests were carried out using a universal testing machine and the debonding pattern was assessed using Adhesive Remnant Index (ARI).

RESULTS

All groups showed clinically acceptable SBS values. The highest SBS was achieved in the HA2 group, followed by Transbond™ XT, HA5 and HA10. There was no significant difference in the ARI scores. In terms of microhardness properties, HA5 and HA10 demonstrated a significant increase after 4 weeks. The results of SEM analysis showed the precipitation of hydroxyapatite crystals and EDAX analysis indicated the increase of calcium and phosphate ion peaks compared to the demineralized sample. The data were analysed using one-way ANOVA and Tukey's Post-hoc test.

CONCLUSIONS

Addition of hydroxyapatite nanoparticles to orthodontic composite can increase the mineral content and microhardness of the adjacent enamel. However, increasing the amount of nanoparticles reduces shear bond strength in a decreasing trend. The above-mentioned findings showed that incremental increase of nanoparticles of HA can be incorporated in composite to a certain extent and limitations are determined by mechanical properties (SBS) required for bracket bonding.

Comparison of the failure rate, bonding time and ARI score of two orthodontic bonding systems: Self-Etch Primer and Conventional Etching Primer: A systematic review and meta-analysis

OBJECTIVE

This study aimed to evaluate the failure incidence of brackets with at least six months follow-up between self-etch primer and conventional etch/primer, as well as to investigate the clinical duration of the bonding process and the amount of adhesive remnant index (ARI).

METHODS

Electronic search was conducted in databases including PubMed, Scopus, Web of Science, ProQuest, ClinicalTrials.gov, and ICTRP (International Clinical Trials Registry Platform). The electronic search targeted only randomized clinical trials and was limited from January 2000 to June 2021. Delphi list is used to evaluate the risk of bias and Stata Version14.2 software was used. This systematic review was conducted according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) and recorded on the Ethics Committee of Research Institute of Dental Sciences, SBMU (IR.SBMU.DRC.REC.1398.240).

RESULTS

Out of 2288 extracted studies, 30 of them entered the full-text evaluation process. According to the inclusion criteria, 15 studies entered this systematic review. Containing 607 participants and 10,563 brackets/teeth. All the included studies were of randomized clinical trials (RCT) design with either parallel or split-mouth design. Comparing the two groups, the risk difference effect (RD)=0.007 CI 95% (-0.004,0.018) indicated a neglectable difference in the risk of bracket failure during treatment between the two groups. The index I²=53.9% indicated moderate heterogeneity in the results. Furthermore, the P-value=0.007 indicated statistical insignificance between the two interventions in terms of failure rate. The clinical duration of bonding time analysis were equal to SMD _Cohen=-2.67 CI95% (-3.49, -1.85), which indicated a statistically significant reduction in clinical process time, using the self-etch primer. Data synthesis for adhesive remnant index could not be conducted due to heterogeneity among included studies.

CONCLUSIONS

There was no difference between the self-etch primer and conventional etch/primer in bracket debonding at a medium level of evidence, However, there was statistically significant reduction in clinical bonding time using self-etch primer.

Superstatistical two-temperature Ising model

The previous approach of the nonequilibrium Ising model was based on the local temperature in which each site or part of the system has its own specific temperature. We introduce an approach of the two-temperature Ising model as a prototype of the superstatistic critical phenomena. The model is described by two temperatures (T_{1},T_{2}) in a zero magnetic field. To predict the phase diagram and numerically estimate the exponents, we develop the Metropolis and Swendsen-Wang Monte Carlo method. We observe that there is a nontrivial critical line, separating ordered and disordered phases. We propose an analytic equation for the critical line in the phase diagram. Our numerical estimation of the critical exponents illustrates that all points on the critical line belong to the ordinary Ising universality class.

Association between Lateral Cephalometric Changes in X-Y Coordinate System and Profile Changes among Skeletal Class III Patients after Orthognathic Surgery

BACKGROUND

Since aesthetic issues are the most important causes of referring skeletal class III patients to surgeons, investigating the impact of orthognathic surgeries on improving patient profiles increases the quality of treatment and quality of life.

METHODS

In a retrospective observational-analytical study, 25 patients older than 18 years with class III skeletal malocclusion who had gone under both orthodontic and double-jaw orthognathic treatment were enrolled. Cephalometric imaging interval was before and at least 6 months after surgery. By defining a number of points and coordinate axes (X-Y), a criterion for comparing hard and soft tissue changes was obtained. These measurements were coordinated, linear and angular. The quantitative data were compared with data obtained using the Likert Scale Questionnaire by means of electronic "Google Forms" that was completed by orthodontists (n=5) and maxillofacial surgeons (n=5) to rank improvement in post-surgical profiles for both cephalometry and photography from poor to pleasant. Spearman Correlation Analysis was conducted between the quantitative and qualitative data.

RESULTS

Vertical changes of point B and horizontal changes of point PNS showed correlation with improvement of patient profile. Changes in N-Pog line (R=-0.4), mandibular plane angle (R=-0.4) and nasolabial angle (NLA) (R=0.38) were significantly correlated with improvement of profiles.

CONCLUSION

In orthognathic double-jaw surgery on patients with skeletal Class III, forward movement of maxilla, upward positioning of mandible (decreasing anterior facial height), decreasing mandibular plane angle and increasing nasolabial angle would result in a better profile.

Innovative evaluation of local injective gel of curcumin on the orthodontic tooth movement in rats

Background

Curcumin is the most active compound in turmeric. It can suppress the nuclear factor kappa-light-chain-enhancer of activated B cells pathway and prevent the osteoclastogenesis procedure. This study aimed to be the first to evaluate the effect of curcumin on the rate of orthodontic tooth movement (OTM).

Materials and Methods

Forty rats were used as follows in each group: (1) negative control: Did not receive any appliance or injection; (2) positive control: received 0.03 cc normal saline and appliance; (3) gelatin plus curcumin (G): Received 0.03 cc hydrogel and appliance; and (4) chitosan plus curcumin (Ch): Received 0.03 cc hydrogel and appliance. They were anesthetized and closed nickel-titanium coil springs were installed between the first molars and central incisors unilaterally as the orthodontic appliance. After 21 days, the rats were decapitated, and the distance between the first and second molars was measured by a leaf gauge. Howship's lacunae, blood vessels, osteoclast-like cells, and root resorption lacunae were evaluated in the histological analysis. Data were analyzed by one-way ANOVA, Tukey's test, and t-test (P < 0.05 consider significant).

Results

No significant difference was found in OTM between groups delivered orthodontic forces. Curcumin inhibited root and bone resorption, osteoclastic recruitment, and angiogenesis significantly.

Conclusion

Curcumin had no significant inhibitory effect on OTM. While it had a significant role on decreasing bone or root resorption (P > 0.05).

Endogenous neurosteroids influence synaptic GABAA receptors during postnatal development

GABA plays a key role in both embryonic and neonatal brain development. For example, during early neonatal nervous system maturation, synaptic transmission, mediated by GABA_A receptors (GABA_A Rs), undergoes a temporally specific form of synaptic plasticity to accommodate the changing requirements of maturing neural networks. Specifically, the duration of miniature inhibitory postsynaptic currents (mIPSCs), resulting from vesicular GABA activating synaptic GABA_A Rs, is reduced, permitting neurones to appropriately influence the window for postsynaptic excitation. Conventionally, programmed expression changes to the subtype of synaptic GABA_A R are primarily implicated in this plasticity. However, it is now evident that, in developing thalamic and cortical principal- and inter-neurones, an endogenous neurosteroid tone (eg, allopregnanolone) enhances synaptic GABA_A R function. Furthermore, a cessation of steroidogenesis, as a result of a lack of substrate, or a co-factor, appears to be primarily responsible for early neonatal changes to GABAergic synaptic transmission, followed by further refinement, which results from subsequent alterations of the GABA_A R subtype. The timing of this cessation of neurosteroid influence is neurone-specific, occurring by postnatal day (P)10 in the thalamus but approximately 1 week later in the cortex. Neurosteroid levels are not static and change dynamically in a variety of physiological and pathophysiological scenarios. Given that GABA plays an important role in brain development, abnormal perturbations of neonatal GABA_A R-active neurosteroids may have not only a considerable immediate, but also a longer-term impact upon neural network activity. Here, we review recent evidence indicating that changes in neurosteroidogenesis substantially influence neonatal GABAergic synaptic transmission. We discuss the physiological relevance of these findings and how the interference of neurosteroid-GABA_A R interaction early in life may contribute to psychiatric conditions later in life.

Axenfeld-Rieger syndrome

Axenfeld-Rieger syndrome (ARS) is a clinically and genetically heterogeneous group of developmental disorders affecting primarily the anterior segment of the eye, often leading to secondary glaucoma. Patients with ARS may also present with systemic changes, including dental defects, mild craniofacial dysmorphism, and umbilical anomalies. ARS is inherited in an autosomal-dominant fashion; the underlying defect in 40% of patients is mutations in PITX2 or FOXC1. Here, an overview of the clinical spectrum of ARS is provided. As well, the known underlying genetic defects, clinical diagnostic possibilities, genetic counseling and treatments of ARS are discussed in detail.

Effect of local injection of Zolena, zoledronic acid made in Iran, on orthodontic tooth movement and root and bone resorption in rats

Background. Anchorage control is an essential part of orthodontic treatment planning, especially in adult patients who demand a more convenient treatment. Zoledronic acid (ZA) is an effective choice to address this problem. It is the most potent member of the bisphosphonates family that has an inhibitory effect on bone resorption by suppressing osteoclast function. Therefore, ZA might be a good option for orthodontic anchorage control. The current study evaluated the effect of local administration of Zolena (ZA made in Iran) on orthodontic tooth movement (OTM) and root and bone resorption. Methods. The experimental group consisted of 30 rats in 3 subgroups (n=10). Anesthesia was induced, and one closed NiTi coil spring was installed between the first molar and central incisor unilaterally, except for the negative control group. The positive control group received vestibular injection of 0.01 mL of saline next to the maxillary first molar, and 0.01 mL of the solution was injected at the same site in the ZA group. After 21 days, the rats were sacrificed and the distance between the first and second molars was measured with a leaf gauge. Histological analysis was conducted by a blind pathologist for the number of Howship's lacunae, blood vessels, osteoclast-like cells and root resorption lacunae. Data were analyzed with ANOVA, Tukey test and t-test. Results. There were no significant differences in OTM between the force-applied groups. ZA significantly inhibited bone/root resorption and angiogenesis compared to the positive control group. Conclusion. Zolena did not decrease OTM but significantly inhibited bone and root resorption. Zolena might be less potent than its foreign counterparts.

Laser Surgery of Soft Tissue in Orthodontics: Review of the Clinical Trials

Introduction: Recently, a wide variety of procedures have been done by laser application in orthodontics. Apart from the mentioned range of various treatments, laser has become a tool for many soft tissue surgeries as an alternative to conventional scalpel-based technique during orthodontic treatments in the management of soft tissue. Due to scarce information in the latter subject, this study was designed in order to include clinical trials that included soft tissue ablation by laser in orthodontics. Methods: Literature was searched based on PubMed and Google Scholar databases in 5 years (2010-2015) with English language restriction and clinical trial design. Studies that performed soft tissue application of laser during orthodontic treatment were extracted by the authors. Results: Only eight studies met the inclusion criteria. No significant difference was found between laser ablation and conventional scalpel technique in the matter of treatment outcome. However, few issues remained to clarify the differences in the mentioned procedures. Conclusion: Laser performance can be recommended in case of preceding less bleeding and discomfort during surgical procedure. There are still quandaries among clinical application of scalpel-based surgery in aesthetic region with bracket-bonded teeth. Precaution and knowledge regarding the characteristics of laser beam such as wavelength, frequency, power and timing is extremely needed.

Comparative effectiveness of Low Level Laser therapy and Transcutaneous Electric Nerve Stimulation on Temporomandibular Joint Disorders

Introduction: Temporomandibular joint disorders (TMDs) are the most common source of pain on the face. There are multiple etiologies, and several types of treatment have been reported. The use of non-invasive and reversible therapies in the treatment of such problems is recommended. The present study evaluated the effect of low-level laser (LLL) therapy and transcutaneous electric nerve stimulation (TENS) on TMDs. Methods: In this single-blind study, 40 patients with temporomandibular disorders were randomly divided into four groups: TENS (TENSTem dental), LLL (diode 810 nm CW), shamTENS, and sham-LLL. All subjects were examined and data on pain and tenderness in the temporomandibular joint (TMJ) and masticatory muscles (using the visual analogue scale) and mouth-opening (distance between incisal edges before feeling pain; mm) were collected before baseline (T1), after each session (T2-T5) and one month after the end of the sessions (T6)), and analyzed using repeated measure analysis of variance (ANOVA) and Bonferroni statistical tests. A P value < 0.05 was considered significant. Results: The decrease in pain (P=0.000), tenderness (P=0.000) and increase in mouth-opening ability (P=0.002) was greater in the TENS and LLL groups than in the placebo groups. At the one-month follow-up, significant decrease in pain and tenderness was recorded in the TENS and LLL groups (P=0.000). There was no significant differences between TENS and LLL and the placebo groups for maximum mouth-opening at the end of the study (P=0.692). Conclusion: Using TENS or LLL therapy can improve TMD symptoms at least for the short term. Although the effects of the placebo played a role in improving symptoms, their effects were less important.

Ultraviolet-induced surface grafting of octafluoropentyl methacrylate on polyether ether ketone for inducing antibiofilm properties

Since octafluoropentyl methacrylate is an antifouling polymer, surface modification of polyether ether ketone with octafluoropentyl methacrylate is a practical approach to obtaining anti-biofilm biocompatible devices. In the current study, the surface treatment of polyether ether ketone by the use of ultraviolet irradiation, so as to graft (octafluoropentyl methacrylate) polymer chains, was initially implemented and then investigated. The Fourier-transform infrared and nuclear magnetic resonance spectra corroborated the appearance of new signals associated with the fluoroacrylate group. Thermogravimetric curves indicated enhanced asymmetry in the polymer structure due to the introduction of the said new groups. Measuring the peak area in differential scanning calorimetry experiments also showed additional bond formation. Static water contact angle measurements indicated a change in wettability to the more hydrophobic surface. The polyether ether ketone–octafluoropentyl methacrylate surface greatly reduced the protein adsorption. This efficient method can modulate and tune the surface properties of polyether ether ketone according to specific applications.

Analysis of Transforming Growth Factor- β1 Expression in Resorptive Lacunae following Orthodontic Tooth Movement in An Animal Model

Objective

Root resorption is a complication of orthodontic treatment and till date, there is a dearth of information regarding this issue. The aim of this study was to determine whether the expression of transforming growth factor-β1 (TGF-β1, an inflammatory cytokine) is related to orthodontic force. Moreover, if associated, the expression level may be helpful in differential diagnosis, control and ultimate treatment of the disease.

Materials and Methods

In this experimental study, a total of 24 eight-week-old male Wistar rats were selected randomly. On day 0, an orthodontic appliance, which consisted of a closed coil spring, was ligated to the upper right first molar and incisor. The upper left first molar in these animals was not placed under orthodontic force, thus serving as the control group. On day 21, after anesthesia, the animals were sacrificed. The rats were then divided into two equal groups where the first group was subjected to histological evaluation and the second group to reverse transcriptase-polymerase chain reaction (RT-PCR). Orthodontic tooth movement was measured in both groups to determine the influence of the applied force.

Results

Statistical analysis of data showed a significant root resorption between the experimental group and control group (P<0.05), however, there was no significant difference in the expression level of the inflammatory cytokine, TGF-β1.

Conclusion

Based on the findings of this study, we suggest that there is a direct relationship between orthodontic force and orthodontic induced inflammatory root resorption. In addition, no relationship is likely to exist between root resorption and TGF-β1 expression in the resorptive lacunae.

The Effect of An Angiogenic Cytokine on Orthodontically Induced Inflammatory Root Resorption

Objective

Orthodontically induced inflammatory root resorption (OIIRR) is an undesirable sequel of tooth movement after sterile necrosis that takes place in periodontal ligament due to blockage of blood vessels following exertion of orthodontic force. This study sought to assess the effect of an angiogenic cytokine on OIIRR in rat model.

Materials and Methods

In this experimental animal study, 50 rats were randomly divided into 5 groups of 10 each: E10, E100 and E1000 receiving an injection of 10, 100 and 1000 ng of basic fibroblast growth factor (bFGF), respectively, positive control group (CP) receiving an orthodontic appliance and injection of phosphate buffered saline (PBS) and the negative control group (CN) receiving only the anesthetic agent. A nickel titanium coil spring was placed between the first molar and the incisor on the right side of maxilla. Twenty-one days later, the rats were sacrificed. Histopathological sections were made to assess the number and area of resorption lacunae, number of blood vessels, osteoclasts and Howship’s lacunae. Data were statistically analyzed using ANOVA and Tukey’s honest significant difference (HSD) test.

Results

Number of resorption lacunae and area of resorption lacunae in E1000 (0.97 ± 0.80 and 1. 27 ± 0.01×10^-3, respectively) were significantly lower than in CP (4.17 ± 0.90 and 2.77 ± 0.01×10-3, respectively, P=0.000). Number of blood vessels, osteoclasts and Howship’s lacunae were significantly higher in E1000 compared to CP (P<0.05).

Conclusion

Tooth movement as the outcome of bone remodeling is concomitant with the formation of sterile necrosis in the periodontal ligament following blocked blood supply. Thus, bFGF can significantly decrease the risk of root resorption by providing more oxygen and angiogenesis.

Helicobacter pylori infection and iron deficiency in patients with coronary artery disease

The aim of this study was to investigate whether impact of the seropositivity to Helicobacter pylori (H pylori) infection on ferritin and iron levels is an independent risk factor for atherosclerosis in patients with cardiovascular disease. The anti H pylori IgG, IgA levels, serum ferritin and iron concentration of 86 patients with cardiovascular disease and 64 participants free of cardiovascular disease as control subjects were determined by ELISA assay. The results of present study showed that seropositivity to H pylori IgG and IgA levels of coronary artery disease (CAD) patients was higher than controls and CAD patients with negative anti H pylori IgG and IgA significantly. A significant negative correlation was found between seropositivity to H pylori IgG and IgA, ferritin and iron levels of CAD patients with seronegativity and seronegativity to H pylori IgG and IgA in comparison with controls. The achieved results from present study suggest that the involvement of H pylori infection in atherosclerosis process is based on the chronic inflammation which might facilitate the CAD-related pathologies. Moreover, impact of the presence of H pylori infection on reduction of the ferritin and iron levels of CAD patients as a risk factor independent of other classic factors including lipid profiles and inflammatory factors was remarkable.

Evaluation of primary stability of innovated orthodontic miniscrew system (STS): An ex-vivo study

BACKGROUND

Stability is determined as one of the requirements in use of Temporary Anchorage Devices (TAD) in orthodontics. Miniscrew has been a widely used Bone Anchor. Compared with mini-implant that necessitates osseointegration; mechanical retention is a determining factor for primary stability of miniscrew. Studies investigated various ways to increase primary stability. The aim of this study is to introduce a new configuration of miniscrew system which is believed to obtain more primary stability.

MATERIAL AND METHODS

Freshly ovine mandibles were cut in blocks. Twenty-seven miniscrews (diameter 1.6 × 8 mm; G2, Dual Top Anchor System, Jeil Medical, Seoul, Korea) were inserted in the blocks and divided in 2 experimental groups: single miniscrew and the innovated design "Seifi Twin Screw (STS)". Primary stability was evaluated by Periotest "M"® device.

RESULTS

Independent t-test showed a significant difference between 2 experimental groups in periotest evaluation (p< 0.05). STS demonstrated higher primary stability due to its mechanical configuration and design.

CONCLUSIONS

The STS provides higher primary stability and was found to be effective in increased success rate of miniscrew systems from the standpoint of primary stability.

KEY WORDS

Anchorage procedures, anchorage techniques, orthodontic anchorage procedures, miniscrews, temporary anchorage device.

The effect of Morus alba leaves extract and powder on resistin levels and liver transaminase enzymes activities in diabetes

The current study was designed to investigate the changes of the resistin, aspartate aminotransferase (AST), alanine aminotransferase (ALT) levels of diabetic rats after treatment with Morus alba leaves flavonoid extract (MLE) and Morus alba leaves powder (MLP). Thirty male wistar rats in five groups including control and diabetic groups were included. Diabetic groups consisted of diabetic control, sham and treated group with MLE and MLP. Type 2 diabetes was induced in rats by administration of streptozotocin (STZ) and - nicotinamide. The serum concentrations of resistin and insulin in the study groups were identified by ELISA. ALT and AST activities were assayed by spectrophotometer. For the first time, it was shown that the uptake of MLE and MLP by diabetic rats could significantly decrease the serum fasting blood sugar (FBS), resistin levels and enzymes activity of ALT and AST and increases the concentration of serum insulin significantly (P<0.05). in comparison with the sham group and diabetic control. The results showed that there was no significant difference between the anti-diabetic and inflammatory properties of MLE and MLP. In this study, the possible protective effect of MLE and MLP administration was evaluated against destructive effect of STZ on liver and pancreas function in diabetic rats. The results showed that these effects may play an important role in the regulating of adipokines secretion such as resistin and insulin secretion which are involved in the control of diabetes and obesity. MLE and MLP treatment could be useful agents in combination with other therapies in diabetes improvement.

Immunolocalization of AMPA receptor subunits within the enteric nervous system of the mouse colon and the effect of their activation on spontaneous colonic contractions

BACKGROUND

The appropriate expression of specific neurotransmitter receptors within the cellular networks that compose the enteric nervous system (ENS) is central to the regulation of gastrointestinal (GI) functions. While the ENS expression patterns of the neurotransmitter glutamate have been well documented, the localization of its receptors on ENS neurons remains to be fully characterized. We investigated the expression patterns of glutamate receptor AMPA subunits within ENS neurons of the mouse colon and the consequences of their pharmacological activation on spontaneous colonic contractility.

METHODS

RT-PCR was used to detect individual AMPA receptor (GluR 1-4) subunit expression at the mRNA level in mouse colon tissue. Immunohistochemistry and confocal microscopy was used to localize the expression of the GluR1 and 4 subunits in colon tissue. Brain tissue was used as a positive control. Organ bath preparations were used to determine the effect of AMPA receptors activation on the force and frequency of colonic longitudinal smooth muscle spontaneous contractions.

KEY RESULTS

GluR1, 3, 4 mRNA was detected in the mouse colon. Immunoreactivity for GluR1 and 4 subunits was detected on the somatic and dendritic surfaces of subpopulations of neurochemically defined ENS neurons. The pharmacological activation of AMPA receptors increased the force but not frequency of spontaneous colonic contractions.

CONCLUSIONS & INFERENCES

Molecularly distinct AMPA receptor subtypes are differentially expressed within the neural networks of the mouse colon and have a direct role in motility. These data provide the rationale for the development of AMPA-selective ligands for the therapeutic delivery to the GIT in motility disorders.

Human colon cancer HT-29 cell death responses to doxorubicin and Morus Alba leaves flavonoid extract

The mechanistic basis for the biological properties of Morus alba flavonoid extract (MFE) and chemotherapy drug of doxorubicin on human colon cancer HT-29 cell line death are unknown. The effect of doxorubicin and flavonoid extract on colon cancer HT-29 cell line death and identification of APC gene expression and PARP concentration of HT-29 cell line were investigated. The results showed that flavonoid extract and doxorubicin induce a dose dependent cell death in HT-29 cell line. MFE and doxorubicin exert a cytotoxic effect on human colon cancer HT-29 cell line by probably promoting or induction of apoptosis.

The Effect of Ovariectomy and Orchiectomy on Orthodontic Tooth Movement and Root Resorption in Wistar Rats

STATEMENT OF THE PROBLEM

Root resorption (RR) after orthodontic tooth movement (OTM) is known as a multifactorial complication of orthodontic treatments. Hormonal deficiencies and their effect on bone turnover are reported to have influences on the rate of tooth movement and root resorption.

PURPOSE

This study was designed to evaluate the effect of female and male steroid sex hormones on tooth movement and root resorption.

MATERIALS AND METHOD

Orthodontic appliances were placed on the right maxillary first molars of 10 ovariectomized female and 10 orchiectomized male Wistar rats as experimental groups and 10 female and 10 male healthy Wistar rats as control groups. NiTi closed-coil springs (9mm, Medium, 011"×.030", Ortho Technology(®); Tampa, Florida) were placed between the right incisors and the first right maxillary molars to induce tipping movement in the first molars with the application of a 60g force. After 21 days, the rats were sacrificed and tooth movement was measured by using a digital caliper (Guanglu, China). Orthodontic induced root resorption (OIRR) was assessed by histomorphometric analysis after hematoxylin and eosin staining of sections of the mesial root.

RESULTS

The rate of tooth movement was significantly higher in all female rats, with the root resorption being lower in the experimental group. The rate of tooth movement in experimental male rats was significantly higher than the control group (p= 0.001) and the rate of root resorption was significantly lower in the experimental group (p= 0.001).

CONCLUSION

It seems that alterations in plasma levels of estrogen, progesterone, and testosterone hormones can influence the rate of OTM and RR. The acceleration in tooth movement increased OTM and decreased RR.

Mutation analysis of the CYP21A2 gene in congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) is an inherited autosomal recessive enzymatic disorder involving the synthesis of adrenal corticosteroids. 21-Hydroxylase deficiency (21-OHD) is the most common form of the disease which is observed in more than 90% of patients with CAH. Early identification of mutations in the genes involved in this disease is critical. A marker of the disease, errors in the CYP21A2 gene, is thought to be part of the pathophysiology of CAH. Therefore, the identification of gene mutations would be very beneficial in the early detection of CAH. This research was a descriptive epidemiological study conducted on individuals elected by the inclusion criteria whom were referred to the Genetic Diagnosis Center of Tabriz during 2012 to 2013. After sampling and DNA extraction, PCR for the detection of mutations in the CYP21A2 gene was performed followed by sequencing. For data analysis, the results of sequencing were compared with the reference gene by blast, Gene Runner and MEGA-5 software. Obtained changes were compared with NCBI databases. The analysis of the sequencing determined the mutations located in Exons 6, 7, 8 and 10. The most frequent findings were Q318X (53%) and R356W (28%). Exon 6 cluster (7%), E431k (4%), V237E (2%), V281L (2%), E351K (2%), R426C (2%) were also frequent in our patients. The most frequent genotype was compound heterozygote, Q318X/R356W. Three rare mutations in our study were E431K, E351K and R426C. Observed mutation frequencies in this study were much higher than those reported in previous studies in Iranian populations. Thus, it seems that it is necessary to follow-up screening programs and use sequencing methods to better identify mutations in the development of the disease.

The Effect of Thyroid Hormone, Prostaglandin E2, and Calcium Gluconate on Orthodontic Tooth Movement and Root Resorption in Rats

STATEMENT OF THE PROBLEM

A major objective of investigators is to clarify the role of metabolites in achievement of maximum tooth movement with minimal root damage during orthodontic tooth movement (OTM).

PURPOSE

The aim of this study was to determine the effect of administration of thyroid hormone, prostaglandin E2, and calcium on orthodontic tooth movement and root resorption in rats.

MATERIALS AND METHOD

Sixty four male Wistar rats were randomly divided into 8 groups of eight rats each: 1- 20µg/kg thyroxine was injected in traperitoneally after installation of the orthodontic appliance.  2- 0.1 ml of 1 mg/ml prostaglandin E2 was injected submucosally.  3- 10% (200 mg/kg) calcium gluconate was injected.  4- Prostaglandin E2 was injected submucosally and 10% calcium was injected intraperitoneally.  5- Thyroxine was injected intraperitoneally and prostaglandin E2 was injected submucosally.  6- 20µg/kg thyroxine with calcium was injected. 7- Prostaglandin E2 was injected submucosally with calcium and thyroxine.  8- Distilled water was used in control group. The orthodontic appliances comprised of a NiTi closed coil were posteriorly connected to the right first molar and anteriorly to the upper right incisor. OTM was measured with a feeler gauge. The mid-mesial root of the first molar and the adjacent tissues were histologically evaluated. The Data were analyzed by one-way ANOVA and Student-Newman-Keuls test.

RESULTS

The highest mean OTM was observed in the thyroxine and prostaglandin E2 group (Mean±SD = 0.7375±0.1359 mm) that was significantly different (p< 0.05). A significant difference (p< 0.05) in root resorption was observed between the prostaglandin E2 (0.0192±0.0198 mm(2)) and the other groups.

CONCLUSION

It seems that the combination of thyroxine and prostaglandin E2, with a synergistic effect, would decrease the root resorption and increase the rate of orthodontic tooth movement in rats.

Effect of nanocrystalline hydroxyapatite socket preservation on orthodontically induced inflammatory root resorption

Objective

Orthodontically induced inflammatory root resorption (OIIRR) is considered to be an important sequel associated with orthodontic tooth movement (OTM). OTM after Socket preservation enhances the periodontal condition before orthodontic space closure. The purpose of this study is to investigate the histologic effects of NanoBone®, a new highly nonsintered porous nano-crystalline hydroxyapatite bone on root resorption following OTM.

Materials and Methods

This experimental study was conducted on four male dogs. In each dog, four defects were created at the mesial aspects of the maxillary and mandibular first premolars. The defects were filled with NanoBone®. We used the NiTi closed coil for mesial movement of the first premolar tooth. When the experimental teeth moved approximately halfway into the defects, after two months, the animals were sacrificed and we harvested the area of interest. The first premolar root and adjacent tissues were histologically evaluated. The three-way ANOVA statistical test was used for comparison.

Results

The mean root resorption in the synthetic bone substitute group was 22.87 ± 11.25×10^-4mm² in the maxilla and 21.41 ± 11.25×10^-4mm² in the mandible. Statistically, there was no significant difference compared to the control group (p>0.05).

Conclusion

The use of a substitution graft in the nano particle has some positive effects in accessing healthy periodontal tissue following orthodontic procedures without significant influence on root resorption (RR). Histological evaluation in the present study showed osteoblastic activity and remodeling environment of nanoparticles in NanoBone®.

Tooth movement alterations by different low level laser protocols: a literature review

Low-Level Laser Therapy (LLLT) provides several benefits for patients receiving orthodontic treatment. According to some literatures, Orthodontic Tooth Movement (OTM) can be enhanced but some investigators have reported contradictory results. This article reviews the literature regarding the different aspects of the use of LLLT on OTM and its alterations. The general data regarding the study design, sample size, wavelength (nm), power (mW), and duration were extracted and recorded independently. Electronic databases of PubMed and ScienceDirect from January 2009 to August 2014 were searched. Also Google Scholar and grey literature was searched for relevant references. Some investigators found that the amount of tooth movement in the Low-Energy Laser Irradiation (LELI) group was significantly greater than in the nonirradiation group by the end of the experimental period. Low-level laser irradiation accelerates the bone remodeling process by stimulating osteoblastic and osteoclastic cell proliferation and function during orthodontic tooth movement. But some researchers have reported that no statistical differences in the mean rate of tooth movement were noted between low energy and high energy experimental sides and their controls. Some evidence shows that low-level laser irradiation accelerates the bone remodeling process and some evidence shows that LLLT has not effect on OTM. In some investigations no statistical differences in the mean rate of tooth movement can be seen between low energy and high energy experimental sides and their controls. It has been shown by authors that laser irradiation can reduce the amount of OTM and a clinical usage for the inhibitory role of low level laser irradiation is enforcing the anchorage unit.

Detection of immunoglobulin IGH gene rearrangements on formalin-fixed, paraffin embedded tissue in lymphoid malignancies

Human lymphomas are aggressive malignant diseases, which can be categorized based on their B and T cell lineage. B-cell lymphomas form around 90% of the total lymphoma cases, the remnants of malignancies arise from the T cell branch. Lymphomas are mostly characterized as clonal proliferations of specific tumor cells. The detection of malignant lymphomas are extensively investigated by their morphological features, immunohistochemistry and flowcytometric immunophenotyping, but in some of cases remained unknown. The BIOMED-2 protocols were used to determine the clonality of IGH gene rearrangements in patients with lymphoma. PCR amplification was performed on FFPE of 50 patients with B-cell lymphoma, which consisted of 11 cases with HLs, 25 cases of B-NHLs and 14 cases of B-LPD (lymphoproliferative disorders) that diagnosed as unclassifiable lymphoma. The rate of positive clonality was detected in 96% (24/25) of B-NHLs, whereas in 4% (1/25) of cases clonality was showed in a polyclonal pattern. In B-HLs, 82% (9/11) of cases showed clonality and 18% (2/11) of the cases showed polyclonality. The rate of positive clonality observed in 64.3% (9/14) of cases with B-LPD and 35.7% (5/14) of cases clonality was not detected in any of immunoglobulin gene family (FR1, FR2, FR3). In groups with DLBCL, clonality was detected in 95% (19/20) of the cases. In patients diagnosed with FL and MALTs 100% cases showed clonality for complete IGH. Our study revealed that EuroClonality BIOMED-2 protocols could be considered as a valuable and reliable method for clonality detection, especially in IGH analysis.

MYCN gene amplification in patients with neuroblastic tumors

Although neuroblastic tumors are the most prevalent solid tumors, little is known about the genetic basis underlying their progression. The prognostic role for the MYCN gene in neuroblastic tumors is irrefutable. The aim of this study is to identify the frequency of MYCN gene amplification and its relationship with clinicopathological and prognostic factors in 40 patients with neuroblastic tumors by using real-time quantitative PCR. There was significant association between the age of older than 18 months and the high number of metastasis. 83.3% of metastatic neuroblastic tumors in patients aged more than 18 months were in stage 4, while it was about 12.5% in patients aged less than 18 months. We found an amplification of MYCN in 19 out of 40 patients. Also, we found MYCN gene amplification in 64% of neuroblastoma (NB) and 8% of gangelioneuroblastoma (GNB) cases. There was a significant association between the histological type of samples with MYCN gene amplification. Neuroblastic tumors have a varied range of MYCN gene amplification depend on histopathology types. No significant associations have been found between MYCN gene amplification and tumor evaluation, CNS involvement, metastasis, stage of disease and patients outcome.

Is C771G polymorphism of MLX interacting protein-like (MLXIPL) gene a novel genetic risk factor for non-alcoholic fatty liver disease?

In a recent study, a genome-wide scan has identified C771G (His241Gln) polymorphism of MLX interacting protein like (MLXIPL) gene that is associated with the level of plasma triglycerides. Since, no study has been reported on the association between MLXIPL gene and non-alcoholic fatty liver disease (NAFLD), we aimed to identify a connection between this genetic variation and NAFLD. Two hundred and thirteen patients with NAFLD and 252 healthy controls were entered into this study. MLXIPL genotypes were determined by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). Our study showed that the single nucleotide polymorphism (SNP) of MLXIPL is significantly associated with NAFLD. Significant differences between cases and controls were observed for MLXIPL genotype frequencies (p<0.002). The frequency of C allele of MLXIPL in patient group was higher than the control group (68.30% vs. 51.59%, respectively; p<0.05). C771G polymorphism in the MLXIPL gene potentially plays a significant role in pathophysiology of non-alcoholic fatty liver disease. Further research is needed to confirm this finding.

Effects of low-level laser therapy on orthodontic tooth movement and root resorption after artificial socket preservation

BACKGROUND

Low- level laser therapy has been used to stimulate the orthodontic tooth movements (OTM) previously. Furthermore, in the orthodontic treatments accompanying tooth extractions, the adjacent teeth move towards the extraction sites and close the space in some cases. Then, the adjacent tooth movements must be prevented in the treatments requiring space. Laser stimulates and at some doses decelerates tooth movement; it also improves healing process and enhances osteogenesis. Hence, it can prevent movement by osteogenesis adjacent to the tooth. The present study investigated the effects of low-level laser therapy on the OTM and root resorption following artificial socket preservation.

MATERIALS AND METHODS

In this experimental animal trial, 16 male albino rabbits were selected with similar characteristics and randomly divided in two groups. Under general anesthesia, an artificial socket, 8 mm in height, was created in the mesial aspect of the first premolars of the rabbits and filled with demineralized freeze dried bone allograft (DFDBA). The first premolars were connected to the incisors using nickel titanium coil springs. In experimental group, gallium-aluminum-arsenide (GaAlAs) laser was irritated mesial to first premolar where artificial socket was created continuously (808 nm). The cycle was 10 days irritation, 14 days rest, 10 days irritation, 14 days rest (Biostimulation mode). Control group was not laser irradiated. All animals were sacrificed after 48 days and the distance between the distal aspect of the first premolars, and the mesial surface of the second premolars was measured with leaf gauge. The specimens underwent histological assessments. Integrity of root and its resorption was observed under microscope calibration. The size of resorption lacunae was calculated in mm(2). Normality of data was proved according to Kolmogorov-Smirnov analysis, and Student's t-test was done. P value less than 0.05 was considered as significant.

RESULTS

The mean OTM were 5.68 ± 1.21 mm in the control group and 6.0 ± 0.99 mm in the laser irradiated teeth with no statistically significant differences(P > 0.75). The mean root resorption was 1.61 ± 0.43 mm(2) and 0.18 ± 0.07 mm(2) in the control and experimental groups respectively being significantly lower in the laser irradiated teeth (P < 0.0001).

CONCLUSION

The findings of the present study show that GaAlAs irradiation together with the application of DFDBA led to limited amount of the stimulated OTM. The laser beam irradiation in combination with alloplastic materials used for socket preservation could reduce the degree of root resorption significantly.

The 808 nm Laser-Assisted Surgery as an Adjunct to Orthodontic Treatment of Delayed Tooth Eruption

INTRODUCTION

Failure of teeth to erupt from gingival tissues at usual developmental time is called delayed tooth eruption (DTE). Delayed tooth eruption lead to prolonged fixed orthodontic treatment and its eventual complications. The purpose of the present study was to evaluate the effect of laser-assisted (808 nm) surgical uncovering, on the tooth emergence and orthodontic treatment of DTE.

METHODS

A total of 16 orthodontic patients were included in this study and were equally assigned to an experimental and a control group. Subjects for experiment consisted of eight patients (6 girls and 2 boys) with a mean age of 14±0.9 years. All patients exhibited delayed second premolar eruption. The laser wavelength was 810 nm and it was set in a continuous wave mode at a power output of 1.6 watt with a 0.3-mm diameter fiber tip. When the target tissue was sufficiently anesthetized, the tip was directed at an angle of 10 to 20 degrees to the tissue (light contact mode); and was applied continuously for approximately 12 Seconds until an acceptable tooth exposure area was visible. The facial axis of the clinical crown (FACC) line represents the most prominent portion of the facial central lobe for premolars. All orthodontic brackets are aligned along this reference and are located on FA (Facial Axis) point. The standard for adequate tooth eruption was the accessibility of facial axis of the clinical crown (FACC) for bonding the brackets. Data gathered from the patients were statistically surveyed and compared by means of Tukey's Test and Analysis of Variance (ANOVA).

RESULTS

All patients showed good gingival status, no significant bleeding during or immediately after the surgery, and acceptable level of healing after laser surgery. The biologic width of the teeth was preserved and no violation of this important periodontal parameter was observed. The average time for accessing the FA point in experimental group was 11±1.1 weeks and the mentioned period was increased to 25±1.8 weeks in control group. The data analysis showed that in patients with DTE, laser intervention significantly accelerated tooth eruption (P < 0.05).

CONCLUSION

Laser-assisted surgical removal of the fibrous tissue over erupting premolars (DTE) with appropriate irradiation parameters appears to be a promising adjunct to orthodontic treatment for bringing the premolar to the aligned and leveled dental arch.

Effect of basic fibroblast growth factor on orthodontic tooth movement in rats

OBJECTIVE

Basic fibroblast growth factor (bFGF) is a cytokine involved in angiogenesis, tissue remodeling and stimulation of osteoblasts and osteoclasts. The present study assesses the effects of a local injection of bFGF on the rate of orthodontic tooth movement.

MATERIALS AND METHODS

: In this laboratory animal study, we randomly divided 50 rats into 5 groups of 10 rats each. Rats received 0.02 cc injections of the following doses of bFGF: group A (10 ng), group B (100 ng) and group C (1000 ng). Group D (positive control) received an orthodontic force and injection of 0.02 cc phosphate buffered saline whereas group E (negative control) received only the anesthetic drug. A nickel titanium spring was bonded to the right maxillary first molar and incisor. After 21 days, the rats were sacrificed and the distance between the first and second right molars was measured by a leaf gauge with 0.05 mm accuracy. ANOVA and Tukey's HSD statistical tests were used for data analysis.

RESULTS

The greatest mean value of orthodontic tooth movement was 0.7700 mm observed in group C followed by 0.6633 mm in group B, 0.5333 mm in group A, 0.2550 mm in group D and 0.0217 mm in group E. There was a significantly higher rate of tooth movement in the test groups compared to the control groups (p<0.05). Among the test groups, the rate of tooth movement in group C was significantly higher than group A (p<0.05). Weight changes after the intervention were not significant when compared to the baseline values, with the exception of group E (p>0.05).

CONCLUSION

The effect of bFGF on the rate of tooth movement was dose-dependent. Injection of 1000 ng bFGF in rats showed the most efficacy.

Determination of orthodontic tooth movement and tissue reaction following demineralized freeze-dried bone allograft grafting intervention

BACKGROUND

Socket preservation after tooth extraction is one of the indications of bone grafting to enhance preorthodontic condition. The aim of this study is to determine the effects of socket preservation on the immediate tooth movement, alveolar ridge height preservation and orthodontic root resorption.

MATERIALS AND METHODS

In a split-mouth technique, twelve sites in three dogs were investigated as an experimental study. Crushed demineralized freeze-dried bone allograft (DFDBA) (CenoBone(®)) was used as the graft material. The defects were made by the extraction of 3(rd) premolar. On one side of each jaw, the defects were preserved by DFDBA and defects of the other side left opened as the control group. Simultaneously the teeth adjacent to the defects were pulled together by a NiTi coil spring. After eight weeks, the amount of (OTM), alveolar height, and root resorption were measured. Analysis of variance was used for purpose of comparison.

RESULTS

There was a slight increase in OTM at grafted sites as they were compared to the control sites (P<0.05). Also a significant bone resorption in control site and successful socket preservation in experimental site were observed. Reduction of root resorption at the augmented site was significant compared to the normal healing site (P<0.05).

CONCLUSION

Using socket preservation, tooth movement can be immediately started without waiting for the healing of the recipient site. This can provide some advantages like enhanced rate of OTM, its approved effects on ridge preservation that reduces the chance of dehiscence and the reduction of root resorption.

Comparative assessment of the sealing ability of Nd:YAG laser versus a new desensitizing agent in human dentinal tubules: a pilot study

Dentinal hypersensitivity is a painful condition that occurs following periodontal treatment. Many treatment alternatives have been considered for this problem, including treatments with laser and dentinal adhesives. This study compared the sealing ability of Nd:YAG laser versus a new resin in scanning electron microscopy (SEM) micrographs. Ten human premolars were sectioned yielding 30 specimens of each premolar, which were randomly divided into three groups. The laser group was irradiated by Nd:YAG laser (1 W, 10 Hz, 60 s), the resin group was treated with the new Seal & Protect resin according to the manufacturer's instructions, and the third group served as the control group and did not receive any interventions. After preparation and gold coating of the samples, they were photographed by SEM at two magnifications (1500× and 4000×). The number and diameter (μm) of the dentinal tubules were recorded in selected fields, and analysis of variance (ANOVA) and Tukey tests were used to determine significant differences between groups. The ANOVA results revealed significant differences in both the mean number (P < 0.001) and diameter (P < 0.05) among the three groups. Further statistical analysis showed a significant difference between the laser group and the resin group in both outcome measures (P < 0.05). Thus, both Nd:YAG laser and the new resin reduced the number and diameter of open dentinal tubules, a result that also explains the desensitization mechanism of these interventions. We further conclude that application of the new resin is more effective than Nd:YAG laser in minimizing the number and diameter of exposed dentinal tubules.

Strength of attachment between band and glass ionomer cement

AIM

To determine the strength of attachment between plain stainless steel band material and glass ionomer cement.

METHODS

Seventy-five extracted upper premolars, free of visible structural defects, were used. The teeth were divided randomly into three groups and embedded in acrylic resin blocks. A short length of plain, stainless steel band material with a welded stainless steel standard edgewise 0.022 inch bracket was adapted to the buccal surface of each tooth. The bracket-stainless steel pads were then cemented to the teeth with either Bandtite (Group 1), Granitec (Group 2) or Ariadent (Group 3) glass ionomer cement and stored in an incubator at 37 degrees C for 30 days. The shear bond strengths of the specimens were measured and compared.

RESULTS

The mean shear bond strengths (SBS) were significantly different: Bandtite 0.7331 +/- 0.056 Mpa; Granitec 0.3869 +/- 0.047 Mpa; Ariadent 0.2931 +/- 0.033 Mpa (ANOVA, p < 0.001). Tukey HSD post-hoc tests also showed significant differences between Bandtite and Granitec, Bandtite and Ariadent, and Granitec and Ariadent (p < 0.001). All specimens failed at the band-cement interface.

CONCLUSION

The highest and lowest SBS were related to Bandtite and Ariadent cements, respectively. All cements had bond strengths less than the range of bond strengths considered to be clinically acceptable for bonded orthodontic attachments. Mechanical factors are important for band retention.

Extraction and purification of crocin from saffron stigmas employing a simple and efficient crystallization method

In this study, total crocin was extracted from saffron stigmas using crystallization method. Ethanol 80% was selected as the best extraction solvent. Crystallization process was carried out in one and two steps at different temperatures. Ethanol 80% was used as crystallization medium. Crocin crystals obtained from the first crystallization had low purity and thus were subjected to the second crystallization. The higher purity crystals were yielded in the second crystallization at -5 degrees C. The purity of crocin crystals was studied using UV-visible spectrophotometery and HPLC in comparison with Fluka product and methanolic extract of saffron stigmas. The results indicated that its purity was extremely higher, about 13 times, more than Fluka product. In spite of our expectation, the Fluka product was not a pure alpha-crocin sample; five other types of crocins in addition to an unknown impurity were seen in its chromatogram. The purity of crystallized total crocin in this work was more than 97%.

The effect of Er, Cr:YSGG laser irradiation on the apical leakage of retrograde cavity

INTRODUCTION

Controversial results have been reported when organic acids, ultrasonic instruments and laser techniques were used to remove smear layer in endodontic treatments. The aim of this study was to evaluate the effect of removing debris and smear layer by Er,Cr:YSGG laser irradiation on the apical leakage of retrograde cavities.

MATERIALS AND METHODS

In this ex vivo study, 24 extracted mandibular single-rooted teeth were selected and instrumented up to K-file size #35. Approximately 3 mm of root apices were dissected perpendicular to the root's long axis. Retrograde cavities with 3 mm depth were prepared and the teeth were randomly assigned to two groups. In one group, the retrograde cavities were filled with amalgam and in the other group, the dentinal surface of the retrograde cavities were lased with Er,Cr:YSGG laser (2W, 15 seconds, G4 tip). The cavities were filled with amalgam; all tooth surfaces except for dissected outsides were covered with blue wax. Then the teeth were immersed in 2% methylene blue dye for 48 hours. The amount of dye penetration into sagittal sections was measured by stereomicroscope at ×20 magnification by two independent observers who were blinded to the experiment. Data were statistically analyzed using student t-test.

RESULTS

This study demonstrated that dye penetration was 0.8 mm (±0.53) in the lased and 0.97 mm (±0.54) in the non-lased group. It showed that, Er,Cr:YSGG laser can remove the debris and smear layer and consequently reduces the amount of dye penetration, although, the difference between the two groups was not statistically significant.

CONCLUSION

This study showed that dye penetration was less in lased group because of the better seal of the dissected surface due to the better removal of the debris and smear layer by laser; further investigations are recommended in this field. [Iranian Endodontic Journal 2009;4(4):144-8].

The role of MSX1 in tooth agenesis in Iranians

INTRODUCTION

MSX1 gene has a critical role in craniofacial development, the aim of this case-control study is to test the hypothesis that MSX1 mutation contributes to congenital tooth agenesis in Iranians.

MATERIALS AND METHODS

The study group consisted of 20 affected individuals with tooth agenesis of lower second premolars or upper lateral incisors with mean age of 24.6. The control group consisted of 20 unaffected individuals. DNA was extracted from all 40 individuals; the polymerase chain reaction (PCR) for MSX1 was carried out with Phenol: Chloroform: Isoamylalchol (PCI) extraction method. Ban II restriction digest and agarose gel electrophoresis of the 20 affected individuals verified the presence of mutation in all 20 affected individuals. The unaffected controls did not show any mutation. Statistical analysis performed by the chi-squared method.

RESULTS

Ban II did not digest PCR product (DNA) in the control group (195 bp band on electrophoresis gel) but digested the affected allele (106 bp and 89 bp bands). There is a statistically significant correlation between tooth agenesis and MSX1 mutation (P < 0.001).

CONCLUSION

The results indicated that MSX1 gene mutation contributes to tooth agenesis in Iranian individuals. As the timing of tooth calcification can vary, radiographic finding of congenital tooth agenesis can be confirmed by this molecular method during different dental ages to achieve certainty.

Effects of two types of low-level laser wave lengths (850 and 630 nm) on the orthodontic tooth movements in rabbits

The effects of low-level lasers on bone cellular activity, bone structures, bone healing, fibroblasts activity and inflammation process have already been investigated. Considering orthodontic tooth movement, which is a complicated inflammatory process involving simultaneous bone apposition and resorption, the aim of this controlled study is to investigate the quantitative effects of a pulsed 850 nm laser (Optodan) and a continuous 630 nm laser (KLO3) on the orthodontic tooth movement in rabbits. This experimental study was conducted on 18 male albino rabbits divided into three equal groups of control, Optodan and KLO3. In all the groups, NiTi-closed coil springs were used on the first mandibular molars with 4-oz tension. The control group was not irradiated by laser, but the teeth in the laser groups were irradiated 9 days according to the periodontal therapeutic protocols. After 16 days, samples were sacrificed. The distance between the distal surface of the first molar and the mesial surface of the second molar was measured with 0.05-mm accuracy. The data were subjected to the statistical tests of Kolmogrov Smirnov and variance analysis. The mean orthodontic tooth movements of the first mandibular molars were 1.7 +/- 0.16 mm in control group, 0.69 +/- 0.16 mm in Optodan group and 0.86 +/- 0.13 mm in KLO3 group. There were statistically significant difference between the control and the two other laser-irradiated groups (P < 0.001). The findings of the present study imply that the amounts of orthodontic tooth movement, after low-level laser therapy, are diminished. It could not be concluded that any low-level laser will reduce the speed of teeth movement in orthodontic treatments, and further studies with less or more energies may show different results.

The effect of prostaglandin E2 and calcium gluconate on orthodontic tooth movement and root resorption in rats

Possible modifications in orthodontic tooth movement (OTM) and root resorption as a result of local injections of prostaglandin E2 (PGE2) alone and with calcium gluconate (Ca) formed the aim of the present study. Twenty-four 8-week-old male Wistar rats were selected and randomly divided into three groups of eight. Both quadrants of the upper jaws of the first group of animals were used; therefore this group comprised two groups: control and normal. The upper left first molars of these eight animals were not placed under orthodontic force and received no injection, to serve as the normal group, considered for root resorption comparison only. The control group had localized submucosal injections of normal saline on the buccal side of the upper right first molar. In the third group, 0.1 ml of 1 mg/ml PGE2 was injected at the same site and the fourth group received an intraperitoneal injection of 200 mg/kg Ca (10%) in addition to the PGE2. All the injections were performed on days 0 and 7. The orthodontic appliance consisted of a closed coil spring ligated to the upper right first molar and incisor, exerting a force of 60 g during the 21-day experimental period, after which the animals were sacrificed. Palatal halves were removed for histological examination and for calculation of the amount of root resorption. Statistical analysis of data showed a significant (P < 0.05) acceleration in OTM after PGE2 injection compared with the control group. The addition of Ca reduced OTM but a significant increase (P< 0.05) was still recorded. A significant difference (P < 0.05) in root resorption was only observed between the PGE2 and normal groups. The findings show the importance of calcium ions working in association with PGE2 in stabilizing root resorption while significantly increasing OTM.