Contribution of different class 2 integron elements to fitness costs in multi-drug resistant Escherichia coli and evaluation of their adaptability in "farm-to-table" environments.

Integrons play a pivotal role in the dissemination of antimicrobial resistance, because they can capture and express exogenous antimicrobial resistance genes. This study aimed to elucidate the structure and contribution of different elements of class 2 integrons to fitness costs in their host bacteria and evaluate their adaptability to the "farm-to-table" process. We mapped 27 typical class 2 integrons of Escherichia coli isolated from aquatic foods and pork products, each harboring an inactive truncated class 2 integrase gene and the gene cassette (GC) array dfrA1-sat2-aadA1 with strong Pc2A/Pc2B promoters. Notably, the fitness costs associated with class 2 integrons depended on the Pc promoter strength and quantity and content of GCs in the array. Additionally, the costs of integrases were activity-dependent, and a balance was identified between GC capture ability and integron stability, which could explain the inactive truncated integrase identified. Although typical class 2 integrons exhibited low-cost structures in E. coli, the bacteria incurred biological costs, including decreasing growth rates and biofilm formation, in farm-to-table environments, especially under low-nutrient conditions. Nevertheless, sub-inhibitory antibiotic concentrations led to the selection of class 2 integron-carrying bacteria. This study provides important insights into how integrons may travel from preharvest to consumer goods.

Assessment of Soft Tissue, Airway Dimension and Hyoid Bone Position in Class II Patients Treated by PowerScope Class 2 Corrector.

AIM: This study aims to assess the changes in the soft tissue, pharyngeal airway dimensions, and hyoid bone position in patients treated with PowerScope Class 2 corrector to correct the skeletal Class II pattern. MATERIALS AND METHODS: This study was conducted on a sample of 20 cases diagnosed with Class II malocclusion. The lateral cephalograms were taken before (T1) and after functional appliance therapy (T2) and were traced. The outcomes were compared for the mean changes in soft tissue, airway way dimension, and hyoid bone position. The paired t-test was used for the data comparisons wherein p < 0.05 was kept for statistical significance. RESULTS: The mean values before and after treatment for H angle, mentolabial angle, lower lip E-line, upper lip S-line, lower lip S-line, and lip strain were 19.88 ± 2.77 vs 17.13 ± 1.659, 94.09 ± 12.164 vs 101.75 ± 11.28, -2.47 ± 1.213 vs -1.38 ± 0.976, 3.99 ± 0.19 vs 2.64 ± 0.32, 9.01 ± 0.247 vs 9.43 ± 0.238, 10.24 ± 0.510 vs 10.64 ± 0.52, respectively, which were statistically significant (p < 0.05). All airway spaces (except for lower pharyngeal space) and hyoid bone parameters were significantly improved posttreatment. CONCLUSION: The facial convexity, upper E-line, Z-angle, nasolabial angle, and lower pharyngeal space did not show statistically significant changes. The rest of the soft tissue parameters, oropharyngeal air spaces, and hyoid positioning measured in the study showed significant improvement after treatment with the PowerScope appliance in Class II patients. CLINICAL SIGNIFICANCE: Class II malocclusion is the most common dental anomaly with a high degree of prevalence in the population. This study will help the clinician in understanding the improvement of soft tissue, airway dimension, and hyoid bone position changes on treatment with a fixed functional appliance for the correction of Class II cases, thereby ensuring the greater success of orthodontic therapy in the future.

Isolated left ventricular assist device implantation produces variable changes to patient body mass index.

BACKGROUND: Body mass index (BMI) is an important consideration for transplant-eligible left ventricular assist device (LVAD) recipients. LVAD therapy's impact on BMI is unclear. We evaluated BMI changes in patients who underwent LVAD implantation. The association between these patients' BMI and the transplant was studied. METHODS: This was a retrospective cohort study of patients who underwent LVAD implantation between January 1, 2012 and December 31, 2018 at our institution. Patients were stratified by preoperative BMI (kg/m2 ) into four groups: <30, 30-34.9, 34.9-39.9, and ≥40. BMI data were collected at 12 and 6 months prior to implantation, time of implantation, and 3- and 6- months postimplantation. RESULTS: A total of 107 patients underwent LVAD implantation at our institution. Data were available for 80 patients. Baseline characteristics included a mean age of 56.0 years, 69% male, and a mean implant BMI of 29.9 ± 6.8 kg/m2 . The mean BMI (kg/m2 ) for each of the BMI (kg/m2 ) groups <30, 30-34.9, 35-39.9, and ≥40 (n = 60, 25, 12, and 10, respectively) was 25.1, 32.5, 36.8, and 43.8, respectively. There was no consistent pattern with weight change across differing implant BMIs. No patient with a BMI of <30 gained sufficient weight to impact transplant candidacy. Twenty-three percent of patients with a BMI of 30-34.9 kg/m2 , 60% of patients with a BMI of 35-39.9 kg/m2 , and 87.5% of patients with a BMI of ≥40 kg/m2 had a 6-month BMI potentially affecting transplant. CONCLUSIONS: Associated weight changes during LVAD support may significantly impact transplant candidacy. Higher BMI groups may benefit from multimodal and multidisciplinary targeted weight-loss interventions.

Paper currency harbours antibiotic-resistant coliform bacteria and integron integrase.

AIMS: This study was designed to analyse the prevalence of class 1 and class 2 integron integrase genes among antibiotic-resistant coliform bacteria isolated from paper currency circulating in Pakistan. METHODS AND RESULTS: A total of 500 individual currency notes were collected from different food vending sites at Lahore, Pakistan. Bacterial population were identified by biochemical and PCR techniques. Antimicrobial susceptibility testing was performed by disc diffusion assay. The highest bacterial population on currency was found from street vendors and butcher shops. Escherichia coli was found to be the most prevalent coliform bacteria followed by Klebsiella sp. and Enterobacter sp. PCR amplification of antimicrobial resistance gene showed the presence of ampC, blaTEM , blaNDM-1 , qnrA, tet(A) and tet(B) genes among coliform isolates. A total of 47 integron integrase bearing strains of coliform bacteria were analysed. Sequence analysis showed the presence of dfrA1-aadA1, dfrA1, dfrA5, dfrA7, aadA1, aadA4 cassette arrays in class 1 integron and dfrA1-sat2-aadA1 in class 2 integrase genes. CONCLUSION: Circulating currency was heavily contaminated with antimicrobial-resistant coliform bacteria bearing class 1 and class 2 integron integrase genes. SIGNIFICANCE AND IMPACT OF THE STUDY: This study describes a potential threat of severe bacterial infections due to improper hand hygiene and community sanitation when dealing with the currency notes.

Prevention of dry socket in mandibular 3rd molars with single preoperative oral dose of metronidazole and amoxicillin compared to conventional therapy.

OBJECTIVE: To compare the efficacy of metronidazole and amoxicillin as preoperative single dose treatment with conventional therapy in prevention of dry socket. METHODS: A double blind randomized controlled trial was conducted at the oral and maxillofacial surgery OPD at DUHS, Karachi. Patients attending and requiring surgical extraction of madibular 3rd molar during October 2018 till April 2019 were randomly divided into 3 groups. Ethical approval was taken from Institutional Review Board of DUHS, Karachi. Informed consent was also taken from patients. First group was given single preoperative oral dose of 400mg metronidazole one hour before extraction, second group was treated with single oral dose of 500mg amoxicillin an hour before tooth extraction, and both of the groups were given painkillers postoperatively. Third group was given 500mg of Amoxicillin BD, 400mg of metronidazole and painkillers postoperatively. Every group had a follow-up on fifth postoperative day. RESULTS: Dry socket was reported among patients 19(8.4 %), among them 4 were males and 15 were females. Chi-square test was used to calculate the p-value (0.066). Results of the present trial were statistically insignificant. Incidence of dry socket in amoxicillin group was 3 (5.5%), in metronidazole was 4 (7.5) and in conventional therapy group was 12(16%). CONCLUSIONS: Present trial was not effective in preventing the occurrence of dry socket by means of single preoperative oral dose of metronidazole and amoxicillin compared to conventional therapy. However, clinically percentage of occurrence of dry socket was higher in conventional group compared to amoxicillin and metronidazole group.

Systolic overload-induced pulmonary inflammation, fibrosis, oxidative stress and heart failure progression through interleukin-1ß.

Chronic heart failure is associated with increased interleukin-1ß (IL-1ß), leukocyte infiltration, and fibrosis in the heart and lungs. Here we further studied the role of IL-1ß in the transition from left heart failure to pulmonary hypertension and right ventricular hypertrophy in mice with existing left heart failure produced by transverse aortic constriction. We demonstrated that transverse aortic constriction-induced heart failure was associated with increased lung inflammation and cleaved IL-1ß, and inhibition of IL-1ß signaling using blocking antibodies of clone B122 effectively attenuated further decrease of left ventricular systolic function in mice with existing heart failure. We found that inhibition of IL-1ß attenuated lung inflammation, inflammasome activation, fibrosis, oxidative stress, and right ventricular hypertrophy. IL-1ß blocking antibodies of clone B122 also significantly attenuated lung T cell activation. Together, these data indicate that IL-1ß signaling exerts a causal role for heart failure progression, or the transition from left heart failure to lung remodeling and right heart hypertrophy.

Interleukin-10 Family Cytokines Immunobiology and Structure.

The Interleukin (IL)-10 cytokine family includes IL-10, IL-19, IL-20, IL-22, IL-24, and IL-26, which are considered as Class 2α-helical cytokines. IL-10 is the most important cytokine in suppressing pro-inflammatory responses in all kinds of autoimmune diseases and limiting excessive immune responses. Due to protein structure homology and shared usage of receptor complexes as well as downstream signaling pathway, other IL-10 family cytokines also show indispensable functions in immune regulation, tissue homeostasis, and host defense. In this review, we focus on immune functions and structures of different cytokines in this family and try to better understand how their molecular mechanisms connect to their biological functions. The molecular details regarding their actions also provide useful information in developing candidate immune therapy reagents for a variety of diseases.

Virulence and resistance on various pathogens mediated by mobile genetic integrons via high flux assays.

BACKGROUND: Recognized as a resistance mechanism responsible for the emergence and prevalence of antimicrobial resistance, integron is widely distributed and spread among clinical microorganisms and play a key role in the dissemination of such antimicrobial resistance, which may eventually contribute to the unleashing of "Super Bugs" In this study, detection assays based on loop-mediated isothermal amplification (LAMP) methodologies targeting on class 1 to class 3 integrase genes was developed and evaluated. METHODS: LAMP methodology was employed to develop novel detection assays on class 1, 2 and 3 integrons. Firstly, this protocol was specifically designed to detect such integrons by targeting integrase genes intI1, intI2 and intI3. Development, evaluation and optimization of such LAMP assays was studied, including the reaction temperature, volumn, time, sensitivity and specificity of both primers and targets. A total of 1082 strains, including 397 integron positive and 685 integron negative microorganisms, were included for the application verification of the established LAMP assays. RESULTS: The indispensability of each primer was confirmed, and the optimal amplification was obtained under 63 °C for 45 min, with 25 µl reaction found to be the most cost-efficient volume. As application was concerned, all of the 397 integron-positive isolates yielded positive amplicons and other 685 integron-negative bacteria were negative for the integron-LAMP assays, revealing totaling 100% detection rate and specificity. CONCLUSIONS: The established integron-LAMP assays was demonstrated to be a valid and rapid detection method for integrons screening, which may aid in both the laboratory and clinical integron screening for microorganisms.

Interferons type II and their receptors R1 and R2 in fish species: Evolution, structure, and function.

Interferon gamma (IFN-γ) is one of the key players in the immune system of vertebrates. The evolution and properties of IFN-γ and its receptors in fish species are of special interest as they point to the origin of innate immunity in vertebrates. We studied the phylogeny, biophysical and structural properties of IFN-γ and its receptors. Our phylogeny analysis suggests the existence of two groups of IFN-γ related proteins, one specific for Acanthomorpha, the other for Cypriniformes, Characiformes and Siluriformes. The analysis further shows an ancient duplication of the gene for IFN-γ receptor 1 (IFN- γR1) and the parallel existence of the duplicated genes in all current teleost fish species. In contrast, only one gene can be found for receptor 2, IFN- γR2. The specificity of the interaction between IFN- γ and both types of IFN- γR1 was determined by microscale thermophoresis measurements of the equilibrium dissociation constants for the proteins from three fish species. The measured preference of IFN- γ for one of the two forms of receptor 1agrees with the bioinformatic analysis of the coevolution between IFN- γ and receptor 1. To elucidate structural relationships between IFN-γ of fish and other vertebrate species, we determined the crystal structure of IFN-γ from olive flounder (Paralichthys olivaceus, PoliIFN-γ) at crystallographic resolution of 2.3 Šand the low-resolution structures of Takifugu rubripes, Oreochromis niloticus, and Larimichthys crocea IFN-γ by small angle X-ray diffraction. The overall PoliIFN-γ fold is the same as the fold of the other known IFN- γ structures but there are some significant structural differences, namely the additional C-terminal helix G and a different angle between helices C and D in PoliIFN-γ.

Crown Reduction and Vital Pulp Therapy in a Dog With Malocclusion.

Crown reduction and vital pulp therapy is an accepted treatment for abnormal occlusion resulting in palatal trauma caused by malpositioned mandibular canine teeth in dogs and cats. This article describes use of mineral trioxide aggregate for vital pulp therapy after crown reduction. A list of materials and commonly used equipment is provided.

Treatment of a class 2 skeletal malocclusion with degenerative arthritis of the condyles using custom-made temporomandibular joint replacements and genioplasty.

This case report presents the use of custom-made temporomandibular joint prostheses in the treatment of a class 2 malocclusion secondary to juvenile idiopathic arthritis. The patient had degeneration of the mandibular condyles with associated arthropathy and dentofacial deformity. Conventional orthognathic treatment was considered, but would not address the arthropathy. The orthognathic movements were accounted for in the design of the prosthesis and the patient's arthralgia, functional limitations and aesthetics were addressed.

Maxillary Canine Tooth Extraction for Class 2 Malocclusion in a Dog.

Malocclusion in dogs is commonly diagnosed in puppies when the primary dentition is present. Interceptive orthodontic treatment may be elected to temporarily resolve painful contact points with the primary dentition. However, the adult dentition must be monitored closely and treated to achieve a lifelong, pain-free occlusion. This case report illustrates interceptive orthodontic treatment of deciduous and permanent dentition to treat a class 2 malocclusion in a dog. Extraction of the permanent maxillary canine tooth was elected to resolve abnormal contact from the mandibular canine in a single anesthetic episode. This treatment option allowed the patient to salvage the structure and function of the mandibular canine, avoid complications associated with mandibular canine extraction, and negate the need for lifelong follow-up of endodontic therapy.

Evaluation of airway dimensions and changes in hyoid bone position following class II functional therapy with activator.

AIM: The aim of this study was to evaluate the long-term effects of Class 2 functional treatment on airway dimensions and positional changes in hyoid bone and compare it with that of an untreated Class 2 control group. METHODS: Lateral cephalograms of 16 patients (eight girls, eight boys, mean chronological age = 11.36 ± 0.77 years) who were treated with activator and 19 patients (11 girls, eight boys, mean chronological age = 12.14 ± 0.65 years) who served as control were used for linear, angular and area measurements regarding airway track and hyoid bone. Statistics. Intra-group comparisons were performed by paired t-test and Wilcoxon test, whereas independent t-test and Mann Whitney-U were used for inter-group comparisons. RESULTS: During treatment (T2-T1), nasopharyngeal height and nasopharyngeal area increased (p < 0.05) and hyoid bone moved downward (H-SN; p < 0.001) and forward (H-C3; p < 0.01). During retention period (T3-T2); nasopharyngeal (p < 0.01) and oropharyngeal area increased (p < 0.05). H-SN (p < 0.01) and C3-H distances (p < 0.05) increased. Hyoid bone position exhibited significant changes (H-SN, p < 0.001; C3-H, p < 0.01). The increases in C3-H in long-term was more in the activator group than control (p < 0.05). CONCLUSIONS: In growing Class 2 patients with mandibular deficiency and airway track without obstructions, functional appliance treatment provided favorable effects on nasopharyngeal and oropharyngeal area throughout the retention period.

Knowledge, Attitude and Perception Regarding Myofunctional Appliance among Children-Prospective Study of Parents' View.

Aim: The current purpose of the survey is to completely evaluate parents' attitudes, knowledge, and perceptions of myofunctional appliances. Materials and Methods: Parents in Chennai participated in this cross-sectional web-based questionnaire survey. Pilot study was carried out to determine the sample size, and 500 individuals were the final sample size. The 10 organized, predesigned, and validated questions are on awareness of myofunctional appliance. Results: The result of the survey showed that in 500 subjects, 79.8% were aware of skeletal problems. The proportion of parents willing to recommend the use of such treatments is about 70%, while 69% believe that myofunctional appliances are important in correcting skeletal problems. Conclusion: The present study has established that most parents know about the functional appliance and have an understanding of how to distinguish between skeletal problems. In order to diagnose skeletal issues in an appropriate age range for the individual, more awareness about appliances is necessary and needs to be developed.

The Impact of Testosterone on Alzheimer's Disease Are Mediated by Lipid Metabolism and Obesity: A Mendelian Randomization Study.

BACKGROUND: To investigate the causal relationship between testosterone (BT) levels and Alzheimer's disease (AD) risk and to quantify the role of obesity and lipid metabolism as potential mediators. METHODS: We used a two-sample, two-step MR to determine:1) the causal effect of BT levels on AD; 2) the causal effect of two lipid metabolites, obesity and LDLc on AD; and 3) the mediating effects of these metabolites. Pooled data for BT levels and lipid metabolism were obtained from the UK Biobank. AD data were obtained from the Alzheimer's Disease Project International Genomics Consortium, FinnGen Consortium, and UK Biobank study. Effect estimates from external genome-wide association study (GWAS) pooled statistics were obtained using inverse variance-weighted (IVW) MR analysis. RESULTS: Higher levels of BT were associated with a reduced risk of AD (odds ratio [OR] 0.9992, 95% CI 0.9985-0.9998, P = 0.019), and there was a negative correlation with LDLc (OR 0.9208, 95% CI 0.8569-0.9895, P = 0.024) and obesity class 2 (OC2) (OR 0.7445, 95% CI 0.5873-0.9437, P = 0.014). Conversely, there was a positive correlation between LDLc (OR 1.0014, 95% CI 1.0000-1.0029, P = 0.043) and OC2 (OR 1.0005, 95% CI 1.0001-1.0009, P = 0.003) and AD. Mediation analysis showed that the indirect effect of BT levels on AD was achieved through LDLc and OC2, which accounted for 17% and 17% of the total effect, respectively. CONCLUSION: Our study identified a causal role of BT levels in LDLc and OC2. BT levels may affect AD through LDLc and OC2 metabolic processes.

A Comparative Analysis of Arch Widths in Class I and Class II Malocclusion: Extraction vs. Non-extraction Treatment.

INTRODUCTION: This study aimed to assess and compare dental arch widths in the anterior and posterior regions among patients undergoing extraction and non-extraction treatments for Class I and Class II malocclusions. MATERIALS AND METHODOLOGY: A total of 40 patients were selected, with 10 in each of the categorized groups based on malocclusion type and treatment status. Dental arch widths were meticulously measured using a digital Vernier caliper at the canine and molar regions to ensure precise data collection. RESULTS: Statistically significant differences were noted when comparing mean inter-canine and molar widths between pre- and post-treatment periods among extraction cases in Class I malocclusion (p < 0.001). Conversely, there were no significant changes observed in arch widths among non-extraction cases in Class I malocclusion. Similarly, significant changes were observed in both extraction and non-extraction cases of Class II malocclusion when comparing mean inter-canine and molar widths between pre- and post-treatment periods (p < 0.05). CONCLUSION: After treatment, both Class I and Class II extraction cases showed an increase in inter-canine arch width, while intermolar arch width remained unchanged, suggesting that the treatment did not significantly alter the buccal corridor. Additionally, there were no notable changes in inter-canine arch widths between pre- and post-treatment in Class I non-extraction cases. However, the Class II non-extraction group exhibited increased upper and lower inter-canine arch widths after treatment.

Comparing the Efficiency of Infrazygomatic Crest (IZC) Screws and Conventional Method for Anterior Retraction in Patients Undergoing Fixed Orthodontic Treatment for Class 2 Malocclusion: A Prospective Clinical Study.

Introduction In orthodontic treatment for class 2 malocclusion, conventional approaches involve extracting the upper first premolars and using methods like en masse retraction and extra-oral or intra-oral distalization. However, these often result in unintended forces and adverse effects. Contemporary techniques, such as maxillary arch distalization with mini-implants like infrazygomatic crest (IZC) implants, offer superior outcomes. IZC implants provide a safe, flexible, and effective site for implant placement, achieving a remarkable 93.7% success rate. Power arms enable precise control, allowing orthodontists to apply controlled forces for optimal tooth movement. This study aims to compare cephalometric parameters pre and post treatment using IZC/buccal shelf (BS) screws and conventional retraction, assessing the efficiency of IZC screws in maintaining arch length during teeth retraction. Methods In a split-mouth study at Yenepoya Dental College, 40 orthodontic patients aged 18-35 were divided into control (premolar extraction, anterior retraction) and study (third molar removal, IZC screw distalization) groups. The control group used a nitinol spring/E chain for retraction, while the study group employed IZC screw-assisted en masse distalization. Regular reviews and adjustments occurred, with radiographs and study models assessed after six months for cephalometric parameters and arch length. Results A significant difference was found in U1-SN (degree), L1-Apog (in mm), L1-NB (degree), and L1-NB (in mm) of pretreatment records, whereas all other measurements showed statistically similar values between conventional and IZC groups. Improvement was higher with the conventional group when compared with IZC groups in these measurements due to the extraction of the first premolars rather than third molar extraction and distalization. However, the IZC group also showed statistically significant improvement in cephalometric parameters such as U1-SN (degree), L1-Apog (in mm), L1-NB (degree), and L1-NB (in mm). Conclusion  The statistical analysis of radiographic and cast measurements in both the maxilla and mandible demonstrated a significant efficiency of IZC screws in teeth retraction while preserving arch length compared to conventional methods. Nevertheless, to strengthen the findings of our study, additional clinical investigations on IZC screws are warranted.

Molecular characterization of nineteen cytokine receptor family B (CRFB) members, CRFB1, CRFB2, CRFB4-17, with three CRFB9 and two CRFB14 in a cyprinid fish, the blunt snout bream Megalobrama amblycephala.

The class II cytokine receptor family members are receptors of class 2 helical cytokines in mammals, and are named cytokine receptor family B (CRFB) in fish. In zebrafish, sixteen members, including CRFB1, CRFB2 and CRFB4-17 were reported. With the availability of genome sequence, a total of nineteen CRFBs was identified in the blunt snout bream (Megalobrama amblycephala), including CRFB1, CRFB2, CRFB4-17 with the presence of three CRFB9 isoforms, and two CRFB14 isoforms. These CRFB molecules contain well conserved features, such as fibronectin type III (FNIII) domain, transmembrane and intracellular domains as other class II cytokine receptors, and are phylogenetically grouped into thirteen clades with their homologues from other species of fish. The CRFB genes were constitutively expressed in organs/tissues examined in the fish. The finding of more CRFB members in the bream may provide clues to understand possible receptor-ligand interaction and their diversity from an evolutionary point of view.

CD4 T cell-activating neoantigens enhance personalized cancer vaccine efficacy.

Personalized cancer vaccines aim to activate and expand cytotoxic antitumor CD8+ T cells to recognize and kill tumor cells. However, the role of CD4+ T cell activation in the clinical benefit of these vaccines is not well defined. We previously established a personalized neoantigen vaccine (PancVAX) for the pancreatic cancer cell line Panc02, which activates tumor-specific CD8+ T cells but required combinatorial checkpoint modulators to achieve therapeutic efficacy. To determine the effects of neoantigen-specific CD4+ T cell activation, we generated a vaccine (PancVAX2) targeting both major histocompatibility complex class I- (MHCI-) and MHCII-specific neoantigens. Tumor-bearing mice vaccinated with PancVAX2 had significantly improved control of tumor growth and long-term survival benefit without concurrent administration of checkpoint inhibitors. PancVAX2 significantly enhanced priming and recruitment of neoantigen-specific CD8+ T cells into the tumor with lower PD-1 expression after reactivation compared with the CD8+ vaccine alone. Vaccine-induced neoantigen-specific Th1 CD4+ T cells in the tumor were associated with decreased Tregs. Consistent with this, PancVAX2 was associated with more proimmune myeloid-derived suppressor cells and M1-like macrophages in the tumor, demonstrating a less immunosuppressive tumor microenvironment. This study demonstrates the biological importance of prioritizing and including CD4+ T cell-specific neoantigens for personalized cancer vaccine modalities.

Evaluation of changes in tongue pressure with twin-block appliance therapy in growing Class II Div 1 malocclusion. An in vivo study.

INTRODUCTION: Twin-block appliance therapy in patients with Class II Div 1 malocclusion positions the mandible anteroinferior leading to possible alterations in tongue pressure, tongue length, and the oropharynx. OBJECTIVES: To evaluate the changes in tongue pressure, tongue length and dimension of the pharyngeal airway in Class II Division 1 subjects before and after twin-block therapy. MATERIALS AND METHODS: Twenty-four subjects were selected, in the range of 10-14 years (mean-12 years). The tongue pressure was recorded at three regions with sensors placed at the incisive papilla and bilaterally at the molar region of the palate for four minutes. The root mean square (RMS) values were recorded and used for further analysis. Evaluation of tongue length and pharyngeal airway dimension was done using a lateral cephalogram. All the measurements were done before and after twin-block appliance therapy. The paired t-test was performed to compare the changes. RESULTS: Resting tongue pressures decreased from pre-treatment levels to post-treatment at all three regions. Change in ANB angle was found to have a significant negative correlation with tongue length, and pharyngeal airway dimension, a significant positive correlation with pressure at incisive papilla and left molar region and no correlation at right molar region. CONCLUSION: There was a decrease in resting tongue pressure as the malocclusion was corrected from Class II to Class I. Hence, this decrease in pressure could be a contributory factor in the maintenance of the dental equilibrium as lighter forces exist in the oral cavity.