Relationship between matrilin-1 gene polymorphisms and mandibular retrognathism.

INTRODUCTION: Mandibular retrognathism is a type of malocclusion that refers to an abnormal posterior position of the mandible as a result of a developmental abnormality. From the literature, it is evident that the mandibular growth pattern is determined by the intramembranous ossification of the mandibular body and endochondral ossification of the condyle. Matrilin-1 is a cartilage extracellular matrix protein, and matrilin-1 gene (MATN1) polymorphisms have been found to be involved in dental malocclusions of humans. In this study, we aimed to examine the association between MATN1 polymorphisms and the risk of mandibular retrognathism, in a case-control study with a South Indian population. METHODS: Eighty-one patients with mandibular retrognathism (SNB, <78°) and 71 controls having an orthognathic mandible (SNB, 80° ± 2°) were recruited. In both the patient and control groups, subjects with an orthognathic maxilla (SNA, 82° ± 2°) were included. Three single nucleotide polymorphisms of the MATN1 gene (rs1149048, rs1149042, and rs1065755) were genotyped using polymerase chain reaction-restriction fragment length polymorphism. The statistical association analysis was performed using the chi-square test. Pair-wise linkage disequilibrium was computed, and haplotypes were compared between subjects and controls. Nonparametric tests were used to compare cephalometric measurements between groups. RESULTS: No polymorphic site deviated from Hardy-Weinberg equilibrium in the controls. The rs1149042 genotypes and alleles were found to be associated with reduced risk of mandibular retrognathism. Furthermore, rs1149042 genotypes were associated with mandibular measurements (SNB and ANB). There was no strong and consistent linkage disequilibrium linkage disequilibrium across two different single nucleotide polymorphisms and haplotypes were not associated with mandibular retrognathism. CONCLUSIONS: The results of our study suggest an association between the MATN1 gene polymorphisms and mandibular retrognathism.

Role of myosin 1H gene polymorphisms in mandibular retrognathism.

INTRODUCTION: Mandibular retrognathism may be the result of a developmental abnormality or the unfavorable positional relationship of developing jaws. Several lines of evidence suggest that muscles are known to have extensive mutual effects on bones. Studies with immunohistochemical staining and gene expression have shown unique combinations of myosin heavy chain isoforms in the masseter muscles. In this study, we aimed to evaluate MYO1H gene polymorphisms and haplotypes as risk factors for mandibular retrognathism. METHODS: Twenty-five subjects with mandibular retrognathism and 25 control subjects of both sexes having an orthognathic maxilla (SNA, 82° ± 2°) between the ages of 12 and 30 years of age were selected for this study. Based on the cephalometric values, subjects with SNB angles smaller than 78° were considered to have mandibular retrognathism. Orthognathic subjects (SNB, 80°) without jaw deformations were used as the comparison group. Three polymorphisms of MYO1H gene (rs10850110, rs11611277, and rs3825393) were genotyped using polymerase chain reaction and restriction fragment length polymorphism. Associations were tested with the Pearson chi-square test and haplotype analyses. RESULTS: The single nucleotide polymorphism rs3825393 showed a statistically significant association with mandibular retrognathism. The cephalometric variables SNB and ANB angles showed significant differences among the various genotypes of rs3825393. Linkage disequilibrium was not strong and significant between the single nucleotide polymorphisms; hence, the haplotypes of the MYO1H gene are not associated with mandibular retrognathism. CONCLUSIONS: These results suggest that the rs3825393 polymorphism of the MYO1H gene is associated with an increased risk for mandibular retrognathism. The relatively small sample size used in the study resulted in modest statistical power. A parallel investigation on another population with larger samples to increase the power could further clarify the role of the MYO1H gene in causing mandibular retrognathism.

A comparative evaluation of ion release from different commercially-available orthodontic mini-implants - an in-vitro study.

BACKGROUND: Titanium alloy mini-implants have become popular in recent times and have been extensively used and studied. Although corrosion resistance of orthodontic materials has always been of concern, this property has been the least explored. The present study aimed to assess the composition, surface characterisation and corrosion resistance of five commercially available mini-implants by assaying ion release in artificial saliva. METHODS: Ten mini-implants each from five companies were obtained: Group 1 - AbsoAnchor (Dentos Inc, South Korea); Group 2 - Microimplant Anchorage System (MIA, Biomaterials Korea); Group 3 - The Orthodontic Mini Anchorage System (TOMAS, Dentaurum, Germany); Group 4 - mini-implants (Denticon, Maharashtra, India); Group 5 - orthodontic mini-implants (lJ.Orthodontics, Kerala, India). One mini-implant from each group was subjected to characterisation and surface microstructure analysis using Energy Dispersive Atomic Spectrometry (EDAX) and Scanning Electron Microscope (SEM), respectively. Ten mini- implants were immersed for 30 days in Fusayama-Meyer artificial saliva solution and the release of titanium, aluminium and vanadium ions was detected with Inductively Coupled Plasma - Optical Emission Spectrometry (ICP-OES). The Kruskal-Wallis test was used for multi-variate analysis. In order to determine the significant differences between the groups on independent samples, the Mann-Whitney U test (bi-variate analysis) was applied. RESULTS AND CONCLUSION: All groups showed machining defects but surface pitting after immersion was mostly evident in Group 4. Although the composition of all the implants was comparable, there was a statistically significant difference in the Ti, Al and V release between Group 4 - the group with maximum release - and Group 2, the group with least release.

Bisphenol A release from orthodontic adhesives and its correlation with the degree of conversion.

INTRODUCTION: Our objective was to quantitatively assess and compare the bisphenol A (BPA) released from an orthodontic adhesive using a light-emitting diode device (LED) or a halogen light-curing unit (HLC) at 3 tip-to-bracket distances (0, 5, and 10 mm) and varying curing times using high-performance liquid chromatography. BPA release with self-etching and moisture-insensitive primers with light-cured and chemically cured composites was also evaluated. BPA release was correlated to the corresponding degree of conversion. METHODS: Our sample consisted of 598 stainless steel first premolar brackets. Of these, 520 were used for assessing BPA release and divided into 13 groups of 40 each. In groups I, II, and III, the composite was cured with the LED for 20 seconds at distances of 0, 5, and 10 mm, respectively. Groups IV, V, and VI were cured with the HLC for 40 seconds at the same 3 distances. Groups VII and VIII were cured for 5 and 10 seconds with the LED, and groups IX and X were cured for 10 and 20 seconds with the HLC at 0-mm distance. Groups XI, XII, and XIII consisted of brackets bonded with a self-etching primer and Transbond (3M Unitek, Monrovia, Calif), with a moisture-insensitive primer and Transbond, and with a chemically cured composite. The remaining 78 brackets were also divided into 13 groups and used for assessing the degree of conversion. RESULTS: The LED devices demonstrated significantly less BPA release and greater degrees of conversion (P <0.05). For both units, BPA release increased and the degree of conversion decreased as the tip distance increased and curing time decreased. The chemically cured group showed significantly less BPA release (P <0.05). Among the light-cured composites, those cured according to the manufacturers' recommendations (40 seconds and 0-mm distance for the HLC unit) released less BPA than did the self-etching primer and the moisture-insensitive primer. The degree of conversion was greatest for the chemically cured composite, whereas it was similar for the conventional, self-etching primer, and moisture-insensitive primer groups. However, correlations ranged from strongly negative to weakly positive between BPA release and degree of conversion. CONCLUSIONS: Clinicians should consider using LEDs in clinical practice and should keep the light-cure tip as close to the bracket as clinically possible. Curing time should be according to the manufacturer's recommendations. These steps will ensure less BPA release and a greater degree of conversion. Since chemically cured composites had less BPA release and a greater degree of conversion, they can be considered superior to light-cured composites in this aspect.

Management of post midface distraction occlusal discrepancy using temporary anchorage devices in a cleft patient.

Open bite deformity following a successful midface advancement by distraction osteogenesis is a common complication. Temporary anchorage devices can be deployed during the distraction and post-distraction settling phases for restoring the occlusion even in severe cases. The following report describes the management of severe anterior open bite following maxillary distraction.

Systemic consumption of probiotic curd and use of probiotic toothpaste to reduce Streptococcus mutans in plaque around orthodontic brackets.

INTRODUCTION: The objectives of the study were to evaluate and compare the effects of the systemic consumption of probiotic curd and the topical application of probiotic toothpaste on the Streptococcus mutans levels in the plaque of orthodontic patients. METHODS: The study consisted of 60 orthodontic patients divided into 3 groups of 20 each. Group 1 was the control group. The patients in group 2 were given probiotic curd, and those in group 3 were asked to brush twice daily with probiotic toothpaste (GD toothpaste; Dental Asia Manufacturing, Shah Alam, Selangor, Malaysia). Samples were collected at 2 times: before the study began and after 30 days. Plaque specimens were collected from the labial surfaces immediately surrounding the orthodontic brackets of the maxillary lateral incisors using a 4-pass technique. The presence of S mutans was evaluated using real-time polymerase chain reaction. Statistical analysis was performed, and comparisons were made using a 2-tailed chi-square test for categorical data (P <0.05). RESULTS: At the end of the study, there were reductions in S mutans concentration in groups 2 and 3 that were statistically significant compared with group 1, but there was no statistically significant difference between groups 2 and 3. CONCLUSIONS: The consumption of probiotic curd and the use of probiotic toothpaste cause a significant decrease in the S mutans levels in the plaque around brackets in orthodontic patients. Although the probiotic toothpaste was more effective than systemic consumption, this was not statistically significant.

Comparison of Streptococcus mutans Adhesion on New and Recycled Metal Brackets: An In Vitro Study.

BACKGROUND: Evaluation of adhesion of Streptococcus mutans on recycled orthodontic brackets is significant, as Streptococcus mutans is the main causative factor in enamel demineralization and many clinicians, in their practice, resort to reconditioning of brackets, as it is cost-effective. Thus, this study aimed to evaluate and compare the adhesion of Streptococcus mutans on new brackets of three different companies (Group I, Group II, and Group III) and brackets recycled by three different recycling methods (RC I: flame heating followed by acid bath; RC II: flame heating followed by ultrasonic cleaning and electropolishing; RC III: flame heating followed by sandblasting and electropolishing). Materials and methods: A total of 10 brackets from each group were incubated with 108 colony-forming units (CFUs) of Streptococcus mutans in trypticase soy broth overnight. The brackets were then washed with phosphate-buffered saline and treated with 0.25% trypsin for 20 minutes followed by vertexing the solution to remove the adhered bacteria and then the solution was plated on the blood agar and incubated overnight. The total viable count of bacteria was quantified. RESULTS: Comparing all the three groups and recycling methods, Group II brackets showed significantly more adhesion, Group I brackets showed lesser adhesion, and Group III brackets showed intermediate adhesion. When comparing recycling methods, all the three methods of recycling with all the three groups showed more bacterial adhesion than the control brackets, which was statistically insignificant (P > 0.05). CONCLUSION: Recycled brackets showed more bacterial adhesion and electropolishing resulted in reduced bacterial adhesion.

In-vivo evaluation of salivary nickel and chromium levels in conventional and self-ligating brackets.

INTRODUCTION: Our objective was to evaluate and compare the salivary levels of nickel and chromium before and 1, 7, and 30 days after placement of conventional and self-ligating appliance systems. METHODS: Twenty women were randomly divided into 2 groups. Patients in group 1 had conventional brackets bonded to their teeth; in group 2, self-ligating brackets were bonded. Four samples of unstimulated saliva were collected from each patient 1 hour before placement of the fixed appliance, and 1, 7, and 30 days after placement of the appliance. The chemical analyses for nickel and chromium levels were performed with an atomic absorption spectrometer (PerkinElmer, Shelton, Conn). Two-way repeated measures analysis of variance by ranks (Friedman test) were used to test the statistical significance of differences in the concentrations of nickel and chromium before and after placement of the appliances. Post-hoc pair-wise comparisons among groups of the same element were calculated by using the Wilcoxon signed rank test. A value of P ≤0.05 was considered significant. RESULTS: Nickel and chromium released into saliva from conventional and self-ligating brackets progressively increased from days 1 to 7 and then decreased at day 30. Nickel release was less, and chromium release was greater in the conventional bracket group. CONCLUSIONS: Both the conventional and the self-ligating brackets did not seem to affect significantly the nickel and chromium concentrations in saliva during the first month of treatment.

Bisphenol A release from an orthodontic adhesive and its correlation with the degree of conversion on varying light-curing tip distances.

INTRODUCTION: The aims of this research were to use high-performance liquid chromatography to assess the bisphenol A (BPA) released from an orthodontic adhesive (Transbond XT; 3M Unitek, Monrovia, Calif) with various light-curing tip distances and to correlate the release to the degree of conversion. METHODS: One hundred thirty-eight premolar brackets were divided into 3 groups of 40 each for the high-performance liquid chromatography analysis and 3 groups of 6 each for assessing the degree of conversion. Fourier transform infrared spectroscopy was used for this purpose. Each group was studied at light-curing tip distances of 0, 5, and 10 mm. Statistical analyses were performed by using 2-way analysis of variance (ANOVA), post-hoc multiple comparisons Tukey HSD tests, and paired t tests. Pearson correlation was used to assess the correlation between the degree of conversion and BPA release. RESULTS: BPA release was greater in specimens cured with a greater light-curing tip distance. The degree of conversion decreased with increased light-curing tip distances. A negative correlation was found between BPA release and degree of conversion. CONCLUSIONS: Clinicians should ensure that the adhesive is completely cured by keeping the light-curing tip as close to the adhesive as clinically possible.

Presence of cariogenic streptococci on various bracket materials detected by polymerase chain reaction.

OBJECTIVE: To determine the in vivo presence of Streptococcus mutans and Streptococcus sobrinus on different bracket materials and to correlate the prevalence with the Visible Plaque Index (VPI) and the Gingival Bleeding Index (GBI). METHODS: Orthodontic brackets made of different materials (stainless steel, gold, ceramic, plastic) were bonded to the upper and lower second premolars in 40 subjects receiving fixed orthodontic appliances. After 30 days, the brackets were debonded and the presence of S. mutans and S. sobrinus on the brackets was determined using the polymerase chain reaction (PCR) technique. The VPI and GBI were recorded and the relationship between the prevalence of the streptococci and the level of oral hygiene was calculated. RESULTS: There were fewer S. mutans and S. Sobrinus over the surface of gold and stainless steel brackets compared with the plastic and ceramic brackets. A statistically significant difference was observed in S. mutans and S. sobrinus prevalence between the metal brackets and the aesthetic brackets. However, there were no statistically significant differences in S. mutons and S. Sobrinus prevalence when the gold and stainless steel brackets were compared. Comparison between the plastic and ceramic brackets revealed a similar finding. Furthermore, a significant correlation was found between the in vivo prevalence of S. mutans and S.sobrinus and the oral hygiene indices (p < 0.05), suggesting that the oral hygiene indices could be a good indicator of S. mutans and S. sobrinus prevalence. CONCLUSIONS: Since microbial adhesion is greater on aesthetic brackets, good oral hygiene during treatment should be emphasised.

Physical, mechanical, and flexural properties of 3 orthodontic wires: an in-vitro study.

INTRODUCTION: Understanding the biologic requirements of orthodontic patients requires proper characterization studies of new archwire alloys. The aims of this study were to evaluate properties of wires made of 2 new materials and to compare their properties with those of stainless steel. METHODS: The sample consisted of 30 straight lengths of 3 types of wires: stainless steel, titanium-molybdenum alloy, and beta-titanium alloy. Eight properties were evaluated: wire dimension, edge bevel, composition, surface characteristics, frictional characteristics, ultimate tensile strength (UTS), modulus of elasticity (E), yield strength (YS), and load deflection characteristics. A toolmaker's microscope was used to measure the edge bevel, and x-ray fluorescence was used for composition analysis. Surface profilometry and scanning electron microscopy were used for surface evaluation. A universal testing machine was used to evaluate frictional characteristics, tensile strength, and 3-point bending. RESULTS: Stainless steel was the smoothest wire; it had the lowest friction and spring-back values and high values for stiffness, E, YS, and UTS. The titanium-molybdenum alloy was the roughest wire; it had high friction and intermediate spring-back, stiffness, and UTS values. The beta-titanium alloy was intermediate for smoothness, friction, and UTS but had the highest spring-back. CONCLUSIONS: The beta-titanium alloy with increased UTS and YS had a low E value, suggesting that it would have greater resistance to fracture, thereby overcoming a major disadvantage of titanium-molybdenum alloy wires. The beta-titanium alloy wire would also deliver gentler forces.

Effects of haemostatic agents on bond strength - An In Vitro study.

AIM: To evaluate and compare the effect of contamination with haemostatic agents like Tranexamic Acid (TA) and Ethamsylate, on the shear bond strength. MATERIALS AND METHODS: There are about 100 extracted human premolars randomly segregated into four groups each consisting of 25 samples. Group I was bonded with Transbond, Group II was bonded with Transbond after blood contamination, while groups III and IV were bonded with Transbond after contamination with Tranexamic acid and the shear bond strength was measured. The data were compared by One- way ANOVA and Tukey (HSD) tests. RESULTS: Group I had the highest shear bond strength (SBS) while Group II, where the teeth were contaminated with blood showed the least SBS values ANOVA indicated significant differences between the four groups (P < .05). Tukey HSD revealed that contamination with TA (Group III) had a statistically higher SBS that contamination with Ethamsylate (Group IV) (P < .05). CONCLUSION: Since tranexamic acid and ethamsylate reduces the bleeding when used during surgery, these haemostatic agents may be considered in bonding situations where blood contamination is anticipated.

Prevalence of Body Dysmorphic Disorder among patients seeking orthodontic treatment.

BACKGROUND: Body Dysmorphic Disorder (BDD) is a psychiatric disorder with delusions about defects in appearance for which patients seek various treatments. Patients with BDD often seek cosmetic procedures, and orthodontic treatment is one among them. This is the first Indian study to determine the prevalence of BDD in an orthodontic outpatient department. MATERIALS AND METHOD: A total of 1184 patients with varying degrees of malocclusion completed the BDD-YBOCS questionnaire, while an experienced orthodontist assessed the severity of malocclusion with a rating scale. RESULTS: Sixty-two patients (5.2%) were screened positive for BDD. Most of the BDD-positive patients were single (p value of 0.02) and had multiple previous consultations for orthodontic treatment (p value of < 0.00**) with a gender predilection toward males (p value of 0.00**), and age was not statistically significant with a p value of 0.3. CONCLUSION: From our study, the prevalence of BDD among orthodontic patients was 5.2%. The orthodontist should be aware of the high prevalence of BDD among orthodontic patients and identify the expectations of the patient at the time of history taking and refer the patient to a psychiatrist for diagnosis and appropriate management.

Cytotoxicity and degree of conversion of orthodontic adhesives.

OBJECTIVES: To test the hypothesis that there is no difference in the cytotoxicity related to the modes of polymerization of five commercially available orthodontic bonding resins, with and without an oxygen-inhibited layer (OIL), and to evaluate the degree of conversion (DC) of these resins and correlate this to cytotoxicity. MATERIALS AND METHODS: Five commercially available orthodontic bonding resins were tested for cytotoxicity and DC. Thirty-six disks of standardized dimensions, for each resin, were used for cytotoxicity assessment. Half of them were washed with 99% acetone to remove the OIL (washed resins), and the remaining disks were left intact (intact resins). Glass disks were used as a control. Vero cells were exposed to intact and washed resins on day 1. Cell viability was determined by tetrazolium bromide reduction assay 1, 3, and 6 days after exposure. The DC of the adhesive specimens of each resin, prepared with a procedure identical to the clinical bonding process, was assessed by Fourier transform infrared spectroscopy. RESULTS: Single-cured systems were comparatively less cytotoxic than dual-cured systems. With removal of the OIL, increased cell viability was noted only with two resins on all three days. Resins tested showed differences in DC. A positive correlation was demonstrated by two resins. CONCLUSION: The hypothesis is rejected. Single-cured systems are superior to dual-cured systems in exhibiting comparatively less toxicity and higher DC. A significant positive correlation was not established between cytotoxicity and DC.

Constancy of cervical vertebral maturation indicator in adults: A cross-sectional study.

OBJECTIVES: The aim of this study was to assess and compare the cervical vertebral maturation stages in adults with different skeletal bases. MATERIALS AND METHODS: A total of 133 lateral cephalograms were selected and allotted in to three groups A (50), B (43) and C (40) having Class I, Class II and Class III skeletal base respectively. Cervical vertebral maturation (CVM) using was assessed using Hassel and Farman method. The morphology of the vertebrae was evaluated by calculating the amount of concavities in the inferior borders of C2, C3 and C4 and the base to anterior height ratio (BAR) and posterior to anterior height ratio (PAR) for C3 and C4. RESULTS: The overall distribution of CVMI 6 was the least followed by stages 5 and 4. The amount of concavities in C2, 3 and 4 were statistically significant (P<0.05) and was highest in Group C. The distribution of C3 and C4 BAR<0.96 was the least. The distribution of CVM 4 and C4 BAR>1.045 was greater in Group B compared to other groups. CONCLUSION: Increased prevalence of lower levels of cervical vertebral maturation was observed in adult lateral cephalograms and in Class II skeletal base in particular.

Lip response to incisor movement in operated cleft lip and palate patients.

BACKGROUND: Although the literature has shown that the lip response to maxillary incisor retraction varies, these studies have been done on a noncleft lip/palate sample. AIM: The aim of this study is to evaluate response of operated cleft lip to orthodontic tooth movement and to determine if there are any differences in the response between the operated cleft lip and the noncleft lip. SETTINGS AND DESIGN: This was a hospital-based retrospective study using radiographs. MATERIALS AND METHODS: Lip changes were evaluated using pre- and post-operative lateral cephalometric radiographs. The experimental group consisted of 12 patients with operated cleft lip while the control group consisted of 12 noncleft patients with dental and skeletal Class I malocclusion. STATISTICAL ANALYSIS: ANOVA was used for statistical analysis. RESULTS: The operated lip responded less to incisor movement than the noncleft group (P < 0.05). While the cleft group demonstrated an increase in upper lip thickness measurements at Point A and vermilion following incisor retraction, the control group showed a decrease in thickness of the upper lip at Point A and an increase at vermilion. CONCLUSION: The cleft team should be aware that the operated lip responds differently to incisor movement. This will enable them to better plan comprehensive treatment for the cleft lip and palate patient.

A modified presurgical orthopedic (nasoalveolar molding) device in the treatment of unilateral cleft lip and palate.

Nasoalveolar molding (NAM) can be done effectively to reshape the nasal cartilage and mold the maxillary dentoalveolar arch before surgical cleft lip repair and primary rhinoplasty. Presurgical NAM helps as an adjunct procedure to enhance the esthetic and functional outcome of the surgical procedures. We have developed a modified NAM device to suit to the needs of the patients coming from distant places for the treatment. This device helps in reducing the number of frequent visits the patient needs to take to the craniofacial center. The purpose of this presentation is to report this treatment technique and discuss its application.

An in Vitro Evaluation of Remineralization Potential of Novamin(®) on Artificial Enamel Sub-Surface Lesions Around Orthodontic Brackets Using Energy Dispersive X-Ray Analysis (EDX).

OBJECTIVE: To evaluate and compare the Ca/P ratio of enamel samples around the orthodontic brackets for time periods of 0, 2 and 10 days in two groups (control group and study group). MATERIALS AND METHODS: Forty extracted teeth were randomly divided into control group and study group. All samples were demineralized and incubated in artificial saliva at 37°C for a period of 10 days after demineralization. During this phase the enamel samples in the study group were treated with remineralizing paste (NuproNusolution containing Novamin®-Dentsply) for 10 days. At the end of the incubation period, Ca/P ratios were analyzed for both the groupsby EDX analysis. Data obtained was subjected to statistical analysis using student t-test for paired samples and Student t- test for individual samples (p ≤ 0.05). RESULTS: It was found that the mean Ca/P ratio was significantly lower for the control group as compared to the study group (p-value < 0.05) after 10 d of incubation. CONCLUSION: Novamin(®) containing remineralization toothpaste showed significant remineralizing potential in inhibition of artificial enamel sub-surface lesion around bracket after 10 days of remineralization phase. EDX element analysis was found to be an efficient method to quantify the changes in mineral content of a sample during in vitro caries studies.