Comparison of biomechanical performance of titanium and polyaryletheretherketone miniscrews at different insertion angles: A finite element analysis.

INTRODUCTION: Only miniscrews [temporary anchoring devices, (TADs)] can provide absolute anchorage during orthodontic treatment. Titanium (Ti) is a fundamental material used in the production of miniscrews, but it has many disadvantages. Polyaryletheretherketone (PEEK) may have various benefits in the production of miniscrews. Finite element analysis (FEA) is a valid and reliable method for calculating stress, strain, and loading forces on complex structures and can be more time- and cost-efficient. OBJECTIVE: To investigate the biomechanical performance of Ti and PEEK as miniscrew biomaterials employing FEA. MATERIALS AND METHODS: This study is a 3-D (3D) simulation with FEA. First, 3D miniscrew modeling is done using Ti base material and PEEK (1.4 mm × 6 mm size), as well as 3D inter-radicular space bone modeling. The simulation was performed by modeling the insertion angles (30°, 60°, and 90°) and applying a 200-gram loading force. The biomechanical performance of the miniscrew was then determined using FEA. RESULTS: As the angle of insertion increases, the tension on the bone decreases, the stress on the TADs increases, and the bone deformation decreases. Compared to TADs made of Ti and PEEK, TADs made of PEEK alone cause more bone stress than TADs made of Ti. The distortion in the maxilla is observed to be larger than in the mandibular. CONCLUSION: PEEK has greater stress on the bones than Ti and may be prospected as an alternative biomaterial for TAD fabrication, as documented in the FEA.

Effects of rapid maxillary expansion on upper airway parameters in OSA children with maxillary restriction: A CBCT study.

BACKGROUND: Rapid maxillary expansion (RME) has been proposed as an effective treatment for pediatric obstructive sleep apnea (OSA) and maxillary restriction in children. This study aimed to evaluate the effect of RME appliances on the nasomaxillary complex dimensions in children with OSA and maxillary constriction. METHODS: This prospective longitudinal study included 34 children aged 8-12 years with maxillary restriction and OSA confirmed by polysomnography who had completed RME therapy. The nasomaxillary complex is segmented into the nasal cavity, maxillary sinuses, and nasopharynx. The effect of RME on nasomaxillary complex dimensions was assessed pre and posttreatment using cone-beam computed tomography, analysis, while a second standard overnight polysomnography (PSG) was performed to assess changes in respiratory parameters. RESULTS: Significant improvements were observed, including inferior maxillary dislocation (S-S1 distance and N-ANS), increased anterior and posterior facial height, and a 5.43 events/h reduction in Apnea-Hypopnea Index (p < .001). The nasal cavity volume increased by 2439 (±584) mm3 (p < .001), nasopharynx size increased by 883 (±479) mm3 (p = .008), mid cross-sectional area increased by 31.74 (±14.50) mm2 (p < .001), and the distance between the right and left maxillary sinuses increased by 8.37 (±3.67) mm (p < .001) all exhibited positive changes, with some insignificant variations in volume change (p = .254). CONCLUSION: RME treatment was found to be effective in improving nasal cavity and nasopharyngeal dimensions, leading to improved respiratory parameters in children with OSA and maxillary constriction. While these results are promising, considerations about the potential long-term benefits of RME on future growth are important. The study provides valuable insights into the efficacy of RME as a treatment option for this pediatric population.

Effects of twin-block appliance on upper airway parameters in OSA children with class II malocclusion and mandibular retrognathia: a CBCT study.

Twin-block appliance had been advocated as a potential treatment option in paediatric obstructive sleep apnoea (OSA) due to their favourable effect in enhancing upper airway parameters and improving OSA symptoms. The aim of this study was to evaluate the effect of twin-block appliance therapy on upper airway parameters/dimensions and the apnoea-hypopnea indexes (AHIs) in OSA children with class II mandibular retrognathic skeletal malocclusion using cone-beam computed tomography. This prospective longitudinal study comprised 34 polysomnography-proven OSA growing children with class II mandibular retrognathic skeletal malocclusion between the ages of 8 and 12 years who had completed myofunctional twin-block therapy and matched corresponding controls. The upper airway was segmented into the nasopharynx, oropharynx, and hypopharynx, and the effect of twin-bock treatment on upper airway parameters/dimensions was assessed pre- and posttreatment using CBCT analysis, while a second standard overnight PSG was performed to determine changes in the AHI. At the nasopharynx level, minimal (nonsignificant) increases in all variables were observed within the twin-block group and between the groups (P > 0.05). At the level of the oropharynx, all variables increased significantly in the treatment group and between groups (P < 0.001), but these increases were nonsignificant in the control group. At the level of the hypopharynx, only the minimum cross-sectional area (MCA) increased significantly in the treatment group (P = 0.003). The change in MCA was also significant between the groups (P = 0.041). In addition, the upper airway length increased significantly in the twin-block group (P = 0.0154), and the AHI decreased by 74.8% (P < 0.001). CONCLUSION: Correction of class II mandibular retrognathic skeletal malocclusion with twin-block appliance resulted in a significant increase in upper airway volume, MCA, anteroposterior and lateral distances of the MCA at the level of the oropharynx, MCA at the level of the hypopharynx and upper airway length, and a significant decrease in AHI, but it had no effect on nasopharynx parameters. WHAT IS KNOWN: • CBCT imaging has been shown to be an effective and precise diagnostic tool for analyzing the upper airways and craniofacial structures. • Twin block appliance may be an effective treatment modality in children with OSA. WHAT IS NEW: • Minimal cross-sectional area of upper ways may be the most relevant potential parameter when explaining how the upper airway anatomy plays role of in the pathogenesis of pediatric OSA. • Twin block appliance induced favorable changes in upper airway morphology (oropharynx area mainly) and respiratory parameters in OSA children with class II malocclusion.

Role of Graphene Oxide in Bacterial Cellulose-Gelatin Hydrogels for Wound Dressing Applications.

Biopolymer-based hydrogels have several advantages, including robust mechanical tunability, high biocompatibility, and excellent optical properties. These hydrogels can be ideal wound dressing materials and advantageous to repair and regenerate skin wounds. In this work, we prepared composite hydrogels by blending gelatin and graphene oxide-functionalized bacterial cellulose (GO-f-BC) with tetraethyl orthosilicate (TEOS). The hydrogels were characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), atomic force microscope (AFM), and water contact angle analyses to explore functional groups and their interactions, surface morphology, and wetting behavior, respectively. The swelling, biodegradation, and water retention were tested to respond to the biofluid. Maximum swelling was exhibited by GBG-1 (0.01 mg GO amount) in all media (aqueous = 1902.83%, PBS = 1546.63%, and electrolyte = 1367.32%). All hydrogels were hemocompatible, as their hemolysis was less than 0.5%, and blood coagulation time decreased as the hydrogel concentration and GO amount increased under in vitro standard conditions. These hydrogels exhibited unusual antimicrobial activities against Gram-positive and Gram-negative bacterial strains. The cell viability and proliferation were increased with an increased GO amount, and maximum values were found for GBG-4 (0.04 mg GO amount) against fibroblast (3T3) cell lines. The mature and well-adhered cell morphology of 3T3 cells was found for all hydrogel samples. Based on all findings, these hydrogels would be a potential wound dressing skin material for wound healing applications.

Evaluation of the Changes of the Intercanine and Intermolar Widths Following Palatal Expansion in the Mixed Dentition Patients with Bilateral Posterior Crossbite: A Systematic Review.

This systematic review aimed to identify the intercanine and intermolar width changes following palatal expansion in bilateral posterior crossbite (PXB) in mixed dentition. This review was registered in the PROSPERO database (CRD42021275833). All randomized controlled trials (RCT) and non-RCT articles between 1980 and August 2022 on the palatal expansion of bilateral PXB in mixed dentition were searched in seven online databases (Google Scholar, Ovid, Web of Science, Scopus, EBSCOHost, Cochrane Library and PubMed). The risk of bias (RoB) of the articles included was analyzed using the Joanna Briggs Institute (JBI) critical appraisal tool. Three non-RCT studies were included and showed a low risk of bias. Meta-analysis on the changes in intercanine and intermolar widths was not performed due to study design heterogeneity. One study reported an over-correction of the bilateral PXB. There is a need for more RCT studies with standardized landmark measurements, outcome assessment methods and retention periods to investigate the interdental changes following palatal expansion.

COL1A1 and FGFR2 Single-Nucleotide Polymorphisms Found in Class II and Class III Skeletal Malocclusions in Javanese Population.

OBJECTIVE: The aim of this article is to analyze and compare the presence of single-nucleotide polymorphisms (SNPs) of COL1A1 and FGFR2 in class II and class III Javanese populations. MATERIALS AND METHODS: Cephalometric radiographs from total 63 patients of class II and III were analyzed. SNP analysis was performed based on both COL1A1 and FGFR2 sequences amplified from total DNA of patients' fresh blood. Principal component analysis was done to calculate the data and find the correlation of the cephalometric indicators influenced by each mutation. t-test and Mann-Whitney analysis were performed to check the significance of differences occurred in each studied parameter (p < 0.05). RESULT: There were three COL1A1 SNPs found in class II and only two in class III, while three FGFR2 SNPs found in both classes. Class II phenotype seemed to be strongly influenced by Y-axis and mandibular plane angle, while class III by lower gonial angle and mandibular plane angle. CONCLUSION: Based on this study, we suggest that rs2249492 of COL1A1 and rs2981582 of FGFR2 play important roles in class III, while rs2277632 of COL1A1 and rs2981582 of FGFR2 play important role in class II skeletal malocclusion in Javanese population.

Dental Arch Relationships of Saudi Children with Unilateral Cleft Lip and Palate.

AIM: To determine dental arch relationships of Saudi children born with nonsyndromic complete unilateral cleft lip and palate (UCLP). MATERIAL AND METHODS: This is a retrospective cohort study that comprised dental study models of 74 UCLP Saudi children aged 8-10 years who were recruited from 14 referral cleft centers. All participants had their cleft lip and palate repaired with no history of alveolar bone graft or any orthodontic treatment. Dental arch relationships of UCLP patients were assessed using the Great Ormond Street, London, and Oslo (GOSLON) Yardstick-a clinical tool that categorizes dental relationships of UCLP children into five discrete grades from I to V. The reliability of the rating was assessed with weighted kappa (κ) statistics. RESULTS: Three children (4.1%) had excellent surgical outcomes (grade I), 18 children (24.3%) filled into grade II (good outcome), 22 subjects (29.7%) had grade III (fair outcome), 27 children (36.5%) had grade IV (poor outcome), and 4 subjects (5.4%) were ranked as having very poor outcomes (grade V). The mean GOSLON score was 3.39. Intrarater and interrater agreements were high indicating good reproducibility. CONCLUSION: Based on the dental arch relationships, the treatment outcome of UCLP Saudi children was unsatisfactory, with a mean GOSLON score of 3.39. Delayed palate repair and the use of presurgical orthopedics may be considered in the future for cleft deformity management. CLINICAL SIGNIFICANCE: To address the effect of particular cleft surgical protocol on dental arch relationships of UCLP patients. How to cite this article: Alforaidi S, Zreaqat M, Hassan R. Dental Arch Relationships of Saudi Children with Unilateral Cleft Lip and Palate. J Contemp Dent Pract 2023;24(12):987-990.

Three-dimensional analysis of upper airways in Class II malocclusion children with obstructive sleep apnea.

BACKGROUND: Morphometric evaluation of upper airways helps in identifying potential craniofacial anatomy that may predispose to pediatric obstructive sleep apnea (OSA). This study evaluated upper airway parameters three-dimensionally in children with OSA, with Class II malocclusion and a retrognathic mandible, to identify cutoff values for cone-beam computed tomography measurements that may predict the presence and severity of pediatric OSA. METHODS: The study comprised 47 growing children with OSA with Class II malocclusion and 47 low-risk OSA-matched controls. Upper airway was segmented into nasopharynx, oropharynx, and hypopharynx using cone-beam computed tomography and MIMICS16.0 software. Parameters included volume, minimum cross-sectional area (CSAmin), anterioposterior and lateral distances of CSAmin, and upper airway length. RESULTS: The volume, cross-sectional area (CSAmin), and anteroposterior and lateral distances of CSAmin were significantly decreased at the level of the oropharynx in patients with OSA. At the level of the hypopharynx, CSAmin was significantly narrower and upper airway length was significantly increased in patients with OSA. OSA predictive cutoff values were proposed as 41.36 mm2 CSAmin at the level of oropharynx, 52.45 mm2 CSAmin at the level of hypopharynx, and 55.47 mm upper airway length. Only CSAmin at the level of the oropharynx had an independent association with OSA severity (P = 0.021). CONCLUSIONS: Significant differences were found in the upper airway parameters of children with OSA compared with corresponding controls. CSAmin may represent part of the issues that play a role in the pathogenesis of OSA and may serve as a predictive of disease severity.

Tonsil Size and Mallampati Score as Clinical Predictive Factors for Obstructive Sleep Apnea Severity in Children.

AIM AND OBJECTIVE: The aim of this study was to determine the clinical utility of body mass index (BMI), tonsil size, and Mallampati scoring in predicting both the presence of and severity of pediatric obstructive sleep apnea (OSA). MATERIALS AND METHODS: This prospective cross-sectional study comprised 78 growing children in the age range of 11-14 years with polysomnography (PSG)-proven OSA and 86 non-OSA corresponding controls. BMI, tonsil size (Friedman grading scale), and Mallampati score were determined for both groups, and related differences were assessed with a t-test, while their independent association with OSA severity was tested with a regression analysis. Statistical significance was set at p <0.05. RESULTS: Male gender, BMI, tonsil size, and Mallampati score were significantly higher in the OSA group (p < 0.05). A significant correlation was recorded between the Mallampati score and OSA severity (p < 0.01), but not with BMI or tonsil size (p > 0.05). For every 1-point increase in the Mallampati scale, the apnea-hypopnea index (AHI) increased by more than five events per hour in the bivariate analysis and by more than three events per hour in the multivariate analysis. CONCLUSION: Male gender, increased BMI, high tonsil, and Mallampati scores were clinical indicators of the presence of OSA. However, only Mallampati scale had a significant association with OSA severity. Clinical diagnostic indicators should be established and encouraged especially in community-based studies. CLINICAL SIGNIFICANCE: Clinical diagnostic indicators are very useful in examining and screening children who are at risk of developing OSA as PSG is expensive and unsuitable for universal use in the pediatric population.

A Review on Current Trends of Polymers in Orthodontics: BPA-Free and Smart Materials.

Polymeric materials have always established an edge over other classes of materials due to their potential applications in various fields of biomedical engineering. Orthodontics is an emerging field in which polymers have attracted the enormous attention of researchers. In particular, thermoplastic materials have a great future utility in orthodontics, both as aligners and as retainer appliances. In recent years, the use of polycarbonate brackets and base monomers bisphenol A glycerolate dimethacrylate (bis-GMA) has been associated with the potential release of bisphenol A (BPA) in the oral environment. BPA is a toxic compound that acts as an endocrine disruptor that can affect human health. Therefore, there is a continuous search for non-BPA materials with satisfactory mechanical properties and an esthetic appearance as an alternative to polycarbonate brackets and conventional bis-GMA compounds. This study aims to review the recent developments of BPA-free monomers in the application of resin dental composites and adhesives. The most promising polymeric smart materials are also discussed for their relevance to future orthodontic applications.

The Short-Term Effect of Active Skeletonized Sutural Distractor Appliance on Temporomandibular Joint Morphology of Class III Malocclusion Subjects.

OBJECTIVES: The purpose of this study was to evaluate the short-term effect of active skeletonized sutural distractor (ASSD) appliance on temporomandibular joint morphology of class III malocclusion subjects. MATERIALS AND METHODS: This was a prospective interventional study. Cone-beam computerized tomography (CBCT) images of 22 patients were taken before and after treatment by using Planmeca Promax 3D CBCT machine version 2.9.2 (Planmeca OY Helsinki, Finland). The condylar width, height, length, roof of glenoid fossa thickness, and all joint spaces were measured. The condylar position was determined based on Pullinger and Hollander formula. The condylar shape was determined as per Kinzinger et al. The condylar volume was calculated by using Mimics software (Materialize, Belgium). STATISTICAL ANALYSIS: Data analysis was performed by using SPSS software version 24. Wilcoxon paired signed-rank test was used to compare the difference in temporomandibular joint morphology and condylar volume between pre- and post-treatment measurements. Chi-square test was used to compare the condylar position and shape. RESULTS: The superior (p = 0.000 on the right side, p = 0.005 on the left side) and posterior joint spaces (p = 0.000 on both sides) were decreased after the treatment, respectively. The condyles were rotated upward and backward, thereby increasing the anterior joint spaces (p = 0.000 on both sides) after the treatment. The condylar volume increases after treatment, but no significant differences were observed (p = 0.903 on the right side, p = 0.062 on the left side). CONCLUSION: The significant changes were observed in joint spaces. The condyles were more anteriorly placed before treatment. Condylar position and shape alter in response to ASSD treatment. The condylar volume did not show any significant change.

Development of Polymeric Nanocomposite (Xyloglucan-co-Methacrylic Acid/Hydroxyapatite/SiO2) Scaffold for Bone Tissue Engineering Applications-In-Vitro Antibacterial, Cytotoxicity and Cell Culture Evaluation.

Advancement and innovation in bone regeneration, specifically polymeric composite scaffolds, are of high significance for the treatment of bone defects. Xyloglucan (XG) is a polysaccharide biopolymer having a wide variety of regenerative tissue therapeutic applications due to its biocompatibility, in-vitro degradation and cytocompatibility. Current research is focused on the fabrication of polymeric bioactive scaffolds by freeze drying method for nanocomposite materials. The nanocomposite materials have been synthesized from free radical polymerization using n-SiO2 and n-HAp XG and Methacrylic acid (MAAc). Functional group analysis, crystallinity and surface morphology were investigated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) techniques, respectively. These bioactive polymeric scaffolds presented interconnected and well-organized porous morphology, controlled precisely by substantial ratios of n-SiO2. The swelling analysis was also performed in different media at varying temperatures (27, 37 and 47 °C) and the mechanical behavior of the dried scaffolds is also investigated. Antibacterial activities of these scaffolds were conducted against pathogenic gram-positive and gram-negative bacteria. Besides, the biological behavior of these scaffolds was evaluated by the Neutral Red dye assay against the MC3T3-E1 cell line. The scaffolds showed interesting properties for bone tissue engineering, including porosity with substantial mechanical strength, biodegradability, biocompatibility and cytocompatibility behavior. The reported polymeric bioactive scaffolds can be aspirant biomaterials for bone tissue engineering to regenerate defecated bone.

Prevalence of Sleep-disordered Breathing and its Association with Obesity among Saudi Schoolchildren.

AIM AND OBJECTIVE: Epidemiological studies of sleep disturbances are essential to promote awareness among families and educational officials and deliver appropriate treatment at a very early timing. The aim of this population-based study was to determine the frequency of sleep-disordered breathing (SDB) symptoms and its association with obesity among schoolchildren in West Saudi Arabia. MATERIALS AND METHODS: This cross-sectional study comprised 2,000 schoolchildren aged 6-12 years. Sleep-disordered breathing symptoms were assessed with Arabic version of Pediatric Sleep Questionnaire (PSQ). Overweight/obesity was evaluated using body mass index (BMI) and their association with SDB was tested using a regression analysis model. RESULTS: Overall, 23% of children were at high risk of SDB. Prevalence of habitual snoring was 15.9% and sleep apnea 4%. Boys were at higher risk of SDB than girls (p = 0.026), while age had no effect (p = 0.254). High-risk SDB had a strong association with sleep symptoms compared to low-risk SDB (p < 0.05). Sleep-disordered breathing increased significantly in overweight and obese children (p = 0.017 and p < 0.001, respectively). CONCLUSION: Around 23% Saudi schoolchildren are at risk of SDB. Related symptoms were strongly associated with high risk of SDB. Overweight and obesity had a strong and progressive association with SDB. CLINICAL SIGNIFICANCE: The results will help in identifying children at high risk of developing SDB and plan for early intervention to avoid the progression of SDB later in life.

Influence of citric acid on the physical and biomineralization ability of freeze/thaw poly(vinyl alcohol) hydrogel.

This work reports the modification of freeze/thaw poly(vinyl alcohol) hydrogel using citric acid as the bioactive molecule for hydroxyapatite formation in simulated body fluid. Inclusion of 1.3 mM citric acid into the poly(vinyl alcohol) hydrogel showed that the mechanical strength, crystalline phase, functional groups and swelling ability were still intact. Adding citric acid at higher concentrations (1.8 and 2.3 mM), however, resulted in physically poor hydrogels. Presence of 1.3 mM of citric acid showed the growth of porous hydroxyapatite crystals on the poly(vinyl alcohol) surface just after one day of immersion in simulated body fluid. Meanwhile, a fully covered apatite layer on the poly(vinyl alcohol) surface plus the evidence of apatite forming within the hydrogel were observed after soaking for seven days. Gel strength of the soaked poly(vinyl alcohol)/citric acid-1.3 mM hydrogel revealed that the load resistance was enhanced compared to that of the neat poly(vinyl alcohol) hydrogel. This facile method of inducing rapid growth of hydroxyapatite on the hydrogel surface as well as within the hydrogel network can be useful for guided bone regenerative materials.

Effect of low level laser and low intensity pulsed ultrasound therapy on bone remodeling during orthodontic tooth movement in rats.

BACKGROUND: Quality bone regeneration, which leads to the improvement of bone remodeling, is essential for orthodontic treatment. In order to improve bone regeneration and increase the amount of tooth movement, different techniques have been implemented. The object of this study is to compare the effects of low-level laser therapy (LLLT), low-intensity pulsed ultrasound (LIPUS), and their combination on bone remodeling during orthodontic tooth movement. METHODS: Eighty (80) male, 6-week-old Sprague Dawley rats were grouped in to four groups, the first group was irradiated with (940 nm) diode laser, second group with LIPUS, and third group with combination of both LLLT and LIPUS. A forth group used was a control group in an incomplete block split-mouth design. The LLLT and LIPUS were used to treat the area around the moving tooth once a day on days 0-7, then the experiment was ended in each experimental endpoint (1, 3, 7, 14, and 21 days). For amount of tooth movement, models were imaged and analyzed. Histological examination was performed after staining with (hematoxylin and eosin) and (alizarin red and Alcian Blue) stain. One step reverse transcription-polymerase chain reaction RT-PCR was also performed to elucidate the gene expression of RANK, RANKL, OPG, and RUNX-2. RESULTS: The amount of tooth movement, the histological bone remodeling, and the RT-PCR were significantly greater in the treatment groups than that in the control group. Among the treatment groups, the combination group was the highest and the LIPUS group was the lowest. CONCLUSION: These findings suggest that LLLT and LIPUS can enhance the velocity of tooth movement and improve the quality of bone remodeling during orthodontic tooth movement.

A CAD/CAM Zirconium Bar as a Bonded Mandibular Fixed Retainer: A Novel Approach with Two-Year Follow-Up.

Stainless steel alloys containing 8% to 12% nickel and 17% to 22% chromium are generally used in orthodontic appliances. A major concern has been the performance of alloys in the environment in which they are intended to function in the oral cavity. Biodegradation and metal release increase the risk of hypersensitivity and cytotoxicity. This case report describes for the first time a CAD/CAM zirconium bar as a bonded mandibular fixed retainer with 2-year follow-up in a patient who is subjected to long-term treatment with fixed orthodontic appliance and suspected to have metal hypersensitivity as shown by the considerable increase of nickel and chromium concentrations in a sample of patient's unstimulated saliva. The CAD/CAM design included a 1.8 mm thickness bar on the lingual surface of lower teeth from canine to canine with occlusal rests on mesial side of first premolars. For better retention, a thin layer of feldspathic ceramic was added to the inner surface of the bar and cemented with two dual-cured cement types. The patient's complaint subsided 6 weeks after cementation. Clinical evaluation appeared to give good functional value where the marginal fit of digitized CAD/CAM design and glazed surface offered an enhanced approach of fixed retention.

Multiplex amplification refractory mutation system (MARMS) for the detection of ß-globin gene mutations among the transfusion-dependent ß-thalassemia Malay patients in Kelantan, Northeast of Peninsular Malaysia.

The aim of this study was to adapt MARMS with some modifications to detect beta mutation in our cohort of thalassemia patients. We focused only on transfusion-dependent thalassemia Malay patients, the predominant ethnic group (95%) in the Kelantanese population. Eight mutations were identified in 46 out of 48 (95.83%) beta thalassemia alleles. Most of the patients (54.2%) were compound heterozygous with co-inheritance Cd 26 (G>A). The frequencies of spectrum beta chain mutation among these patients are presented in Table 2. Among the transfusion dependent beta thalassemia Malay patients studied, 26 patients were found to be compound heterozygous and the main alleles were Cd 26 (G>A). Compound heterozygous mutation of Cd 26 (G>A) and IVS 1-5 (G>C) were 12 (46.2%), Cd 26 (G>A) and Cd 41/42 (TTCT) were 9 (34.6%), Cd 26 (G>A) and IVS 1-1 (G>C) were 2 (7.7%) respectively. Meanwhile the minority were made of a single compound heterozygous of Cd 26 (G>A) and Cd 71/72, Cd 26 (>A) and Cd 17 (A>T), Cd 26 (G>A) and -28 (G>A) respectively. Twenty out of forty six patients were shown to have homozygous of IVS 1-5 (G>C) were 2 (10.0%), Cd 26 (G>A) were 15 (75.0%), Cd 19 (A>G) were 1 (5.0%), and IVS 1-1 (G>T) were 2 (10.0%). The beta chain mutations among the Kelantanese Malays followed closely the distribution of beta chain mutations among the Thais and the Malays of the Southern Thailand. The G-C transition at position 5 of the IVS 1-5 mutation was predominant among the Malay patients. In conclusion, this method has successfully identified the mutation spectrum in our cohort of transfusion-dependent beta thalassemia patients, and this method is equally effective in screening for mutation among thalassemia patients.

Overview of non-invasive factors (low level laser and low intensity pulsed ultrasound) accelerating tooth movement during orthodontic treatment.

The need for orthodontic treatment is increasing all the time. As the treatment is time consuming ranging from a year to several years, any method of reducing the period of treatment and increasing the quality of the tissue will be beneficial to patients. The use of non-invasive techniques such as low level laser therapy and low intensity pulsed ultasound in accelerating orthodontic tooth movement are promising. Thus, this overview study will help to generate more understanding about the background information and the possible applications of them in daily orthodontics, depending on previous literature searching for reviews and original research articles.

Effect of 940 nm low-level laser therapy on osteogenesis in vitro.

Bone regeneration is essential in medical treatment, such as in surgical bone healing and orthodontics. The aim of this study is to examine the effect of different powers of 940 nm diode low-level laser treatment (LLLT) on osteoblast cells during their proliferation and differentiation stages. A human fetal osteoblast cell line was cultured and treated with LLLT. The cells were divided into experimental groups according to the power delivered and periods of exposure per day for each laser power. The (3-(4,5-dimethylthiazol-2yl)-2,5 diphenyl tetrazolium bromide) (MTT) assay was used to determine cell proliferation. Both alkaline phosphatase and osteocalcin activity assays were assessed for cell differentiation. All treatment groups showed a significant increase in cell proliferation and differentiation compared to the control group. Regarding the exposure time, the subgroups treated with the LLLT for 6 min showed higher proliferation and differentiation rates for the powers delivered, the 300-mW LLLT group significantly increased the amount of cell proliferation. By contrast, the 100 and 200 mW groups showed significantly greater amounts of cell differentiation. These results suggest that the use of LLLT may play an important role in stimulating osteoblast cells for improved bone formation.