Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 40
Filter
1.
JAMA Health Forum ; 4(10): e233648, 2023 10 06.
Article in English | MEDLINE | ID: mdl-37889483

ABSTRACT

Importance: During the COVID-19 pandemic, a large fraction of mental health care was provided via telemedicine. The implications of this shift in care for use of mental health service and quality of care have not been characterized. Objective: To compare changes in care patterns and quality during the first year of the pandemic among Medicare beneficiaries with serious mental illness (schizophrenia or bipolar I disorder) cared for at practices with higher vs lower telemedicine use. Design, Setting, and Participants: In this cohort study, Medicare fee-for-service beneficiaries with schizophrenia or bipolar I disorder were attributed to specialty mental health practices that delivered the majority of their mental health care in 2019. Practices were categorized into 3 groups based on the proportion of telemental health visits provided during the first year of the pandemic (March 2020-February 2021): lowest use (0%-49%), middle use (50%-89%), or highest use (90%-100%). Across the 3 groups of practices, differential changes in patient outcomes were calculated from the year before the pandemic started to the year after. These changes were also compared with differential changes from a 2-year prepandemic period. Analyses were conducted in November 2022. Exposure: Practice-level use of telemedicine during the first year of the COVID-19 pandemic. Main Outcomes and Measures: The primary outcome was the total number of mental health visits (telemedicine plus in-person) per person. Secondary outcomes included the number of acute hospital and emergency department encounters, all-cause mortality, and quality outcomes, including adherence to antipsychotic and mood-stabilizing medications (as measured by the number of months of medication fills) and 7- and 30-day outpatient follow-up rates after discharge for a mental health hospitalization. Results: The pandemic cohort included 120 050 Medicare beneficiaries (mean [SD] age, 56.5 [14.5] years; 66 638 females [55.5%]) with serious mental illness. Compared with prepandemic changes and relative to patients receiving care at practices with the lowest telemedicine use: patients receiving care at practices in the middle and highest telemedicine use groups had 1.11 (95% CI, 0.45-1.76) and 1.94 (95% CI, 1.28-2.59) more mental health visits per patient per year (or 7.5% [95% CI, 3.0%-11.9%] and 13.0% [95% CI, 8.6%-17.4%] more mental health visits per year, respectively). Among patients of practices with middle and highest telemedicine use, changes in adherence to antipsychotic and mood-stabilizing medications were -0.4% (95% CI, -1.3% to 0.5%) and -0.1% (95% CI, -1.0% to 0.8%), and hospital and emergency department use for any reason changed by 2.4% (95% CI, -1.5% to 6.2%) and 2.8% (95% CI, -1.2% to 6.8%), respectively. There were no significant differential changes in postdischarge follow-up or mortality rates according to the level of telemedicine use. Conclusions and Relevance: In this cohort study of Medicare beneficiaries with serious mental illness, patients receiving care from practices that had a higher level of telemedicine use during the COVID-19 pandemic had more mental health visits per year compared with prepandemic levels, with no differential changes in other observed quality metrics over the same period.


Subject(s)
Antipsychotic Agents , COVID-19 , Mental Disorders , Telemedicine , Aged , Female , Humans , United States/epidemiology , Middle Aged , Medicare , Cohort Studies , Aftercare , Pandemics , Patient Discharge , Mental Disorders/epidemiology , Mental Disorders/therapy , COVID-19/epidemiology
2.
J Prim Care Community Health ; 14: 21501319231159311, 2023.
Article in English | MEDLINE | ID: mdl-36905315

ABSTRACT

BACKGROUND: In the Veterans Health Administration (VA), Primary Care-Mental Health Integration (PC-MHI) clinics offer mental health services embedded in primary care, a strategy shown to reduce overall specialty mental health clinic burden while facilitating prompt referrals when indicated. Among newly initiated patients, same-day access to PC-MHI from primary care increases subsequent specialty mental health engagement. However, the impact of virtual care on the association between same-day access to PC-MHI and subsequent mental health engagement remains unclear. OBJECTIVE: To examine the effects of same-day access to PC-MHI and virtual care use on specialty mental health engagement. METHODS: We used administrative data from 3066 veterans who initiated mental health care at a large, California VA PC-MHI clinic during 3/1/2018 to 2/28/2022 and had no previous mental health visits for at least 2 years prior to the index appointment. We conducted Poisson regression analyses to examine the effects of same-day access to PC-MHI, virtual access to PC-MHI and their combined effect on subsequent specialty mental health engagement. RESULTS: Same-day access to PC-MHI from primary care was positively associated with specialty mental health engagement (IRR = 1.19; 95% CI 1.14-1.24). Virtual access to PC-MHI was negatively associated with specialty mental health engagement (IRR = 0.83; 95% CI 0.79-0.87). The positive effect of same-day access on specialty mental health engagement was smaller among patients who initiated PC-MHI in a virtual visit (IRR = 1.07) compared to in-person visits (IRR = 1.29; 95% CI 1.22-1.36). CONCLUSIONS: Although same-day access to PC-MHI increased overall specialty mental health engagement, the magnitude of this effect varied between in-person and virtual modalities. More research is needed to understand mechanisms of the association between virtual care use, same-day access to PC-MHI, and specialty mental health engagement.


Subject(s)
Delivery of Health Care, Integrated , Veterans , United States , Humans , Mental Health , Veterans Health , United States Department of Veterans Affairs , Primary Health Care
3.
J Prim Care Community Health ; 13: 21501319221091430, 2022.
Article in English | MEDLINE | ID: mdl-35426344

ABSTRACT

INTRODUCTION: Same-day referrals from primary care to mental health increase subsequent mental health treatment engagement. VA Primary Care-Mental Health Integration (PC-MHI) clinics offer integrated mental health services embedded in primary care clinics, providing a key entry point to mental health care. Although telehealth use expanded rapidly after the onset of COVID-19, the impact of telehealth on same-day primary care access among new PC-MHI mental health patients is unknown. To address this knowledge gap, we examined associations between telehealth use and same-day primary care access in VA PC-MHI. METHODS: We examined electronic health record data to identify same-day primary care appointments among PC-MHI patients who initiated care during 3/1/2018 to 10/29/2021. We used logistic regression analyses to evaluate the effect of telehealth on same-day primary care access. Time, demographic characteristics, mental health diagnoses (PTSD and depression), and substance use disorder diagnosis were evaluated as covariates. RESULTS: New PC-MHI patients who were seen via telehealth were less likely to receive same-day primary care access than patients seen in person (OR: 0.54; 95% CI: 0.41-0.71; P < .001). CONCLUSIONS: Despite the potential advantages of using telehealth to increase access, VA patients with an initial PC-MHI visit via telehealth were less likely than patients seen in person to be referred from primary care. Telehealth may adversely affect primary care referrals to mental health services, an outcome that could ultimately reduce specialty mental health care continuity. There is an urgent need to identify strategies to facilitate PC-MHI care coordination in the telehealth context.


Subject(s)
COVID-19 , Delivery of Health Care, Integrated , Telemedicine , COVID-19/epidemiology , COVID-19/therapy , Humans , Mental Health , Primary Health Care , United States , United States Department of Veterans Affairs
4.
J Mol Graph Model ; 109: 108020, 2021 12.
Article in English | MEDLINE | ID: mdl-34592583

ABSTRACT

In the family of serine/threonine kinases, Cyclin Dependent Kinase 4 (CDK4), is an important regulator in numerous signal transduction pathways. The cell cycle is dysregulated in human breast adenocarcinoma (MCF-7). A set of various categorical QSAR models were generated and validated in the current examination. A recursive partition model, with predictive ability shown by an accuracy of greater than 0.90, was used for virtual screening of 500,000 molecules. Following a consecutive series of molecular docking procedures, followed by pharmacokinetic analysis of 49759 molecules predicted to have pIC50 greater than 7.39, 25 molecules displayed properties that could be described as drug-like. We selected the lead molecules in the MCF-7 cell line based on its ability to promote cell cycle progression.


Subject(s)
Breast Neoplasms , High-Throughput Screening Assays , Cyclin-Dependent Kinase 2 , Cyclin-Dependent Kinase 4 , Female , Humans , MCF-7 Cells , Molecular Docking Simulation
5.
Psychiatr Serv ; 72(11): 1324-1327, 2021 11 01.
Article in English | MEDLINE | ID: mdl-34030456

ABSTRACT

OBJECTIVE: The authors examined access to care among persons with serious mental illness during the pandemic and disparities in use of virtual care among this population versus among individuals with other psychiatric diagnoses. METHODS: Data from the Veterans Health Administration were used to examine whether the number of visits for serious mental illness differed for January-September 2019 versus the same period in 2020. Mixed-effects regression analyses tested whether the post-COVID-19 rate of growth in virtual care differed for people with serious mental illnesses versus those with other diagnoses. RESULTS: Fewer visits for serious mental illnesses occurred during the initial weeks of the pandemic but not subsequently. The rate of growth in video visits during 2020 was slower for serious mental illnesses than for other psychiatric diagnoses. CONCLUSIONS: Several months after the pandemic's start, the total number of visits for serious mental illnesses was similar to 2019; however, adoption of video care was slower than for other psychiatric diagnoses.


Subject(s)
COVID-19 , Mental Disorders , Veterans , Health Services Accessibility , Humans , Mental Disorders/epidemiology , Pandemics , SARS-CoV-2
6.
J Proteome Res ; 19(11): 4706-4717, 2020 11 06.
Article in English | MEDLINE | ID: mdl-32960061

ABSTRACT

Corona virus disease (COVID-19) is a dangerous disease rapidly spreading all over the world today. Currently there are no treatment options for it. Drug repurposing studies explored the potency of antimalarial drugs, chloroquine and hydroxychloroquine, against SARS-CoV-2 virus. These drugs can inhibit the viral protease, called chymotrypsin-like cysteine protease, also known as Main protease (3CLpro); hence, we studied the binding efficiencies of 4-aminoquinoline and 8-aminoquinoline analogs of chloroquine. Six compounds furnished better binding energies than chloroquine and hydroxychloroquine. The interactions with the active site residues especially with Cys145 and His41, which are involved in catalytic diad for proteolysis, make these compounds potent main protease inhibitors. A regression model correlating binding energy and the molecular descriptors for chloroquine analogs was generated with R2 = 0.9039 and Q2 = 0.8848. This model was used to screen new analogs of primaquine and molecules from the Asinex compound library. The docking and regression analysis showed these analogs to be more potent inhibitors of 3CLpro than hydroxychloroquine and primaquine. The molecular dynamic simulations of the hits were carried out to determine the binding stabilities. Finally, we propose four compounds that show drug likeness toward SARS-CoV-2 that can be further validated through in vitro and in vivo studies.


Subject(s)
Betacoronavirus , Chloroquine , Coronavirus Infections/virology , Cysteine Endopeptidases , Pneumonia, Viral/virology , Protease Inhibitors , Viral Nonstructural Proteins , Betacoronavirus/chemistry , Betacoronavirus/metabolism , COVID-19 , Catalytic Domain , Chloroquine/analogs & derivatives , Chloroquine/chemistry , Chloroquine/metabolism , Coronavirus 3C Proteases , Cysteine Endopeptidases/chemistry , Cysteine Endopeptidases/metabolism , Humans , Hydroxychloroquine/chemistry , Hydroxychloroquine/metabolism , Molecular Docking Simulation , Molecular Dynamics Simulation , Pandemics , Protease Inhibitors/chemistry , Protease Inhibitors/metabolism , Protein Binding , SARS-CoV-2 , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/metabolism
7.
J Mol Graph Model ; 82: 48-58, 2018 06.
Article in English | MEDLINE | ID: mdl-29680736

ABSTRACT

Cyclin Dependent Kinase 4 is a striking target for the proposal of anti-cancer drugs since its overexpression is associated with various types of cancers. In the present study, 2D and 3D atom based QSAR study were accomplished with 6 component PLS factor for 230 pyrido[2,3-d]pyramidine correspondents along with flexible ligand docking in the extra precision mode with the application of core constraints followed by the binding energy determinations. Kernel based partial least square analysis fitting with fingerprints initially created worthy models, among which the one with molprint2D fingerprints generated a noble model with a score value of 0.8322. Atom Based 3D QSAR resulted in an effective model with Regression coefficient (R2 = 0.8372), and Q2 = 0.7381. Docking experiments exposed hydrogen bonding interactions with hinge region residues, salt bridge formation and л-л stacking interaction as the leading non-covalent interactions causative of the inhibitory activity of CDK4 inhibitors. The primary factors that induced the stability of protein-ligand complex are the van der Waals interactions, lipophilic interactions and coulombic interactions.


Subject(s)
Cyclin-Dependent Kinase 4/chemistry , Molecular Docking Simulation , Molecular Dynamics Simulation , Protein Kinase Inhibitors/chemistry , Quantitative Structure-Activity Relationship , Cyclin-Dependent Kinase 4/antagonists & inhibitors , Humans , Hydrogen Bonding , Hydrophobic and Hydrophilic Interactions , Ligands , Protein Binding , Protein Kinase Inhibitors/pharmacology
8.
Healthc (Amst) ; 6(4): 231-237, 2018 Dec.
Article in English | MEDLINE | ID: mdl-29102480

ABSTRACT

Many integrated health systems and accountable care organizations have turned to intensive primary care programs to improve quality of care and reduce costs for high-need high-cost patients. How best to implement such programs remains an active area of discussion. In 2014, the Veterans Health Administration (VHA) implemented five distinct intensive primary care programs as part of a demonstration project that targeted Veterans at the highest risk for hospitalization. We found that programs evolved over time, eventually converging on the implementation of the following elements: 1) an interdisciplinary care team, 2) chronic disease management, 3) comprehensive patient assessment and evaluation, 4) care and case management, 5) transitional care support, 6) preventive home visits, 7) pharmaceutical services, 8) chronic disease self-management, 9) caregiver support services, 10) health coaching, and 11) advanced care planning. The teams also found that including social workers and mental health providers on the interdisciplinary teams was critical to effectively address psychosocial needs of these complex patients. Having a central implementation coordinator facilitated the convergence of these program features across diverse demonstration sites. In future iterations of these programs, VHA intends to standardize staffing and key features to develop a scalable program that can be disseminated throughout the system.


Subject(s)
Primary Health Care/methods , Program Development/methods , United States Department of Veterans Affairs/trends , Case Management , Case-Control Studies , Humans , Primary Health Care/standards , Quality Improvement , Transitional Care/trends , United States , United States Department of Veterans Affairs/organization & administration , Veterans/statistics & numerical data
9.
Angew Chem Int Ed Engl ; 55(4): 1432-5, 2016 Jan 22.
Article in English | MEDLINE | ID: mdl-26662576

ABSTRACT

Michael addition reactions between biological thiols and endocyclic olefinic maleimides are extensively used for site-specific bioconjugation. The resulting thio-succinimidyl linkages, however, lack stability because of their susceptibility to thiol exchange. Reported herein is that in contrast to their endocyclic counterparts, exocyclic olefinic maleimides form highly stable thio-Michael adducts which resist thiol exchange at physiological conditions. A high-yielding approach for synthesizing a variety of exocyclic olefinic maleimides, by 4-nitrophenol-catalyzed solvent-free Wittig reactions, is reported. Mechanistic studies reveal that the catalyst facilitates the formation of the Wittig ylide intermediate through sequential proton donation and abstraction. Overall, this report details an improved thiol bioconjugation approach, a facile method for synthesizing exocyclic olefinic maleimides, and demonstrates that phenolic compounds can catalyze ylide formation.


Subject(s)
Alkenes/chemistry , Maleimides/chemical synthesis , Sulfhydryl Compounds/chemistry , Cyclization , Electrophoresis, Polyacrylamide Gel , Kinetics , Maleimides/chemistry , Proton Magnetic Resonance Spectroscopy
10.
J Clin Diagn Res ; 9(1): FF04-7, 2015 Jan.
Article in English | MEDLINE | ID: mdl-25738004

ABSTRACT

OBJECTIVE: To evaluate the effect of Edrophonium on blood glucose levels in euglycemic albino rats through OGTT. MATERIALS AND METHODS: Twelve Swiss albino rats weighing around 150-200 gms of either sex were randomly selected from the central animal facility, JSSMC, Mysore and divided into two groups. The control group received distilled water (25ml/kg body wt.) per orally, test groups received Edrophonium (6.3mg/kg/day) intravenously for five days. On the fifth day, following overnight fasting, half an hour after drug administration in all the groups of rats Oral Glucose Tolerance Test was performed, by administering oral glucose in dose of 0.6gm/kg body weight. The capillary blood glucose levels were measured at 0, 60 and 150 min, by rat tail snipping method using (ACCUCHEK) glucometer. RESULTS: The Capillary Blood Glucose levels of Edrophonium group was less when compared to control group at all-time intervals. CONCLUSION: Edrophonium showed the hypoglycemic activity when given for five days intravenously in euglycemic albino rats through Oral Glucose Tolerance Test.

11.
Am J Med Qual ; 30(3): 255-62, 2015 May.
Article in English | MEDLINE | ID: mdl-24714824

ABSTRACT

Operational waste, or workflow processes that do not add value, is a frustrating but nonetheless largely tolerated barrier to efficiency and morale for medical trainees. In this article, the authors tested a novel reporting system using several submission formats (text messaging, e-mail, Web form, mobile application) to allow residents to report various types of operational waste in real time. This system informally promoted "lean" principles of waste identification and continuous improvement. In all, 154 issues were submitted between March 30, 2011, and June 30, 2012, and categorized as closely as possible into lean categories of operational waste; 131 issues were completely addressed with the requested outcome partially or fully implemented or with successful clarification of existing policies. A real-time, voluntary reporting system can effectively capture trainee observations of waste in health care and training processes, give trainees a voice in a hierarchical system, and lead to meaningful operations improvement.


Subject(s)
Documentation , Efficiency, Organizational , Internship and Residency/organization & administration , Humans , Internship and Residency/standards , Time Factors , Workflow
12.
Angle Orthod ; 85(2): 196-205, 2015 Mar.
Article in English | MEDLINE | ID: mdl-24901066

ABSTRACT

OBJECTIVE: To evaluate the stress patterns in temporomandibular joint (TMJ) during mandibular protraction at different horizontal advancements with constant vertical height in a construction bite using a three-dimensional finite element method. MATERIALS AND METHODS: A three-dimensional computer-aided model was developed from the magnetic resonance imaging (MRI) of a growing boy (age 12 years) using MIMICS software (version 7.0, Materialise, Leuven, Belgium). Stresses with constant vertical opening of 5 mm changing the sagittal advancements from 0 mm to 5 mm and 7.5 mm were recorded. Differences in magnitude and pattern of stresses were compared. RESULTS: The tensile stresses in the posterosuperior aspect of the condylar head and on the posterior aspect of the glenoid fossa migrated posteriorly with increased bite advancements. The location of tensile stresses changed in the condylar head and fossa on mandibular protraction of 5 mm to 7 mm. CONCLUSION: This study indicates that larger horizontal advancements of construction bites may not be favorable for tissues of TMJ. Clinical application necessitates study on an animal model.


Subject(s)
Finite Element Analysis , Imaging, Three-Dimensional/methods , Mandibular Advancement/methods , Temporomandibular Joint/physiology , Biomechanical Phenomena , Child , Computer Simulation , Computer-Aided Design , Humans , Image Processing, Computer-Assisted/methods , Magnetic Resonance Imaging/methods , Male , Malocclusion, Angle Class II/therapy , Mandibular Condyle/anatomy & histology , Mandibular Condyle/physiology , Models, Biological , Orthodontic Appliances, Functional , Retrognathia/therapy , Stress, Mechanical , Temporal Bone/anatomy & histology , Temporal Bone/physiology , Temporomandibular Joint Disc/anatomy & histology , Temporomandibular Joint Disc/physiology , Vertical Dimension
13.
Org Biomol Chem ; 11(38): 6477-82, 2013 Oct 14.
Article in English | MEDLINE | ID: mdl-23969565

ABSTRACT

An N-heterocyclic carbene (NHC)-catalyzed reaction of alkenes with aromatic aldehydes providing for a high yield synthesis of α-acyloxy ketones and esters has been described. This unprecedented regioselective oxidative process employs NBS and Et3N in stoichiometric amounts and O2 (1 atm) as an oxidant under ambient conditions in DMSO as a solvent.


Subject(s)
Aldehydes/chemistry , Alkenes/chemistry , Esters/chemical synthesis , Heterocyclic Compounds/chemistry , Ketones/chemical synthesis , Methane/analogs & derivatives , Catalysis , Esters/chemistry , Ketones/chemistry , Methane/chemistry , Molecular Structure , Oxygen/chemistry , Stereoisomerism
14.
J Alzheimers Dis ; 35(1): 147-57, 2013.
Article in English | MEDLINE | ID: mdl-23380994

ABSTRACT

The relationship of cerebrovascular risk and Alzheimer's disease (AD) pathology to cognition in pre-dementia has been extensively investigated and is well-established. Cerebrovascular risk can be measured using a Framingham Stroke Risk Profile (FSRP) score, while positron emission tomography (PET) scans with 2-(1-{6-[(2-[F-18]fluoroethyl)(methyl)amino]-2-naphthyl}ethylidene)malononitrile (FDDNP) measure AD neuropathology (i.e., amyloid-ß plaques and tau tangles). Here we report results of 75 healthy non-demented subjects (mean age, 63 years) who underwent neuropsychological testing, physical assessments, and FDDNP-PET scans. Controlling for AD family history, education, and APOE4 status in a general linear model, higher FSRP risk and global FDDNP-PET binding were each associated with poorer cognitive functioning. The interaction of FSRP and global FDDNP-PET binding was not significant in the model, indicating that stroke risk and plaque and tangle burden each contributed to worse cognitive performance. Within our healthy volunteers, age, blood pressure, and antihypertensive medication use were vascular risks that contributed significantly to the above findings. These findings suggest that even mild cerebrovascular risk may influence the extent of cognitive dysfunction in pre-dementia, along with amyloid-ß and tau burden.


Subject(s)
Cerebrovascular Disorders/diagnostic imaging , Cerebrovascular Disorders/psychology , Cognition Disorders/diagnostic imaging , Cognition Disorders/psychology , Positron-Emission Tomography/methods , Radiopharmaceuticals , Adult , Aged , Aged, 80 and over , Cerebrovascular Disorders/metabolism , Cognition Disorders/metabolism , Female , Humans , Male , Middle Aged , Neuropsychological Tests , Protein Binding/physiology , Radiopharmaceuticals/metabolism , Risk Factors
15.
J Orthod ; 39(4): 249-55, 2012 Dec.
Article in English | MEDLINE | ID: mdl-23269688

ABSTRACT

OBJECTIVE: The purpose of this investigation was to quantitatively evaluate mini-screw deflection and stress distribution associated with two different cortical bone thicknesses (CBTs) under loading with two applied forces at four different angles. MATERIAL AND METHODS: Four finite element models (ANSYS 11) of bone with mini-screws (Dentos) inserted at 90° angulation to the cortical surface were made as follows: model A: CBT 1·5 mm, load 200 g; model B: CBT 2 mm, load 200 g; model C: CBT 1·5 mm, load 300 g; model D: CBT 2 mm, load 300 g. In each model, the loading force was applied at angulations of 70, 90, 110 and 130° to the long axis of the mini-screw. The elastic modulus of the cortical bone, cancellous bone and mini-screw were kept at 15, 1·5 and 114 GPa, respectively. The maximum equivalent stress (MES) distribution and maximum deflection (MD) at the mini-screw to bone interface was evaluated in the four models at each angulation. RESULTS: In each model, MES and MD of the mini-screw decreased when the angulation of loading increased from 70 (MES = 2·81 MPa) to 130° (MES = 1·92 MPa). Mean MES with model A = 2·21 MPa, model B = 1·83 MPa, model C = 3·06 MPa and model D = 2·67 MPa. CONCLUSIONS: The MES and MD both decrease as the angulation of mini-screw loading increases, with increasing load differences occur in MD but the MES remains similar, whilst differences were observed in both MES and MD as CBT increased.


Subject(s)
Bone and Bones/physiology , Dental Implants , Finite Element Analysis , Orthodontic Anchorage Procedures/instrumentation , Orthodontic Appliance Design , Biomechanical Phenomena , Computer Simulation , Elastic Modulus , Humans , Imaging, Three-Dimensional/methods , Materials Testing , Miniaturization , Models, Biological , Osseointegration/physiology , Stress, Mechanical
17.
Angle Orthod ; 82(5): 799-805, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22309123

ABSTRACT

OBJECTIVE: To investigate stress distribution in the roots of maxillary central incisors bearing various types of root morphologies with regard to application of different types of orthodontic forces using the finite element model (FEM). MATERIALS AND METHODS: FEMs of maxillary central incisors with different root morphologies (normal, short, blunt, dilacerated, and pipette) were constructed, and orthodontic forces in various directions (intrusion, extrusion, tipping, and rotational) were applied to the tooth axis at the bracket level. RESULT: On application of various forces, significantly increased stress was seen at the apex of the root with dilacerated morphology and at the cervical one-third region of the tooth with the short root. Increased stress was observed at the middle one-third region in the tooth with the pipette-shaped root during intrusion and extrusion. CONCLUSIONS: In the present study, the stress distribution pattern indicates that the maxillary central incisors with deviated root morphology are at higher risk of root resorption.


Subject(s)
Incisor/anatomy & histology , Maxilla/anatomy & histology , Orthodontic Appliances , Root Resorption/etiology , Tooth Movement Techniques/adverse effects , Tooth Root/anatomy & histology , Computer Simulation , Dental Stress Analysis , Finite Element Analysis , Humans , Incisor/physiology , Maxilla/physiology , Models, Dental , Tooth Root/physiology
18.
Int J Clin Pediatr Dent ; 5(2): 163-6, 2012 May.
Article in English | MEDLINE | ID: mdl-25206161

ABSTRACT

UNLABELLED: Crowding and irregularity remain a consistent problem for children. Management of space problems continues to play an important role in a dental practice. It also represents an area of major interaction between the primary provider and the specialists. Proximal stripping is routinely carried out to avoid extraction in borderline cases where space discrepancy is less and in cases where there is a discrepancy between the mesio- distal width of maxillary and mandibular teeth to satisfy Bolton ratio. Proximal stripping is carried out using of metallic abrasive strip, safe sided carborundum disk, or with long thin tapered fissure burs with air rotor. The use of rotary cutting instrument can harm the pulp by exposure of mechanical vibration and heat generation (in some cases). Whereas, the large diameter of the disk obstructs vision of the working area. Also fracturing away a portion is a common problem with disk. Tapered fissure burs cut the tooth structure as the width of bur or overcutting may occur of the tooth structure due to high speed. The use of metallic abrasive strip is the safest procedure amongst the above. The strip can be placed in the anterior region without any difficulty but using it in the posterior region is difficult as, it is difficult to hold it with fingers while stripping the posterior teeth. To avoid this inconvenience here with a simple and economical way of fabricating strip holder from routine lab material is presented. CLINICAL IMPLICATIONS: Proper management of space in the primary and mixed dentitions can prevent unnecessary loss in arch length. Diagnosing and treating space problems requires an understanding of the etiology of crowding and the development of the dentition to render treatment for the mild, moderate and severe crowding cases. Most crowding problems with less than 4.5 mm can be resolved through preservation of the leeway space, regaining space or limited expansion in the late mixed dentition. In cases with 5 to 9 mm of crowding, some can be approached with expansion after thorough diagnosis and treatment planning. Most of these cases will require extraction of permanent teeth to preserve facial esthetics and the integrity of the supporting soft tissue. Sequential proximal stripping is routinely carried out to avoid extraction in borderline cases where space discrepancy is less and reserved for treatment of mild tooth-size/arch-size discrepancies. How to cite this article: Sharma NS, Shrivastav SS, Hazarey PV. Mastering Interproximal Stripping: With Innovations in Slenderization. Int J Clin Pediatr Dent 2012;5(2):163-166.

19.
Biotechnol Prog ; 26(5): 1424-30, 2010.
Article in English | MEDLINE | ID: mdl-20549681

ABSTRACT

A dermal tissue construct composed of human dermal fibroblasts and a chitosan sponge has been developed, targeted towards the treatment of diabetic nonhealing ulcers. The construct has been designed in a way that the dermal fibroblasts are arranged as a three-dimensional sheet adhered entirely on one side of the chitosan sponge. This design would allow maximal diffusion of growth factors from the cells to the wound bed when the construct is applied on the wound with the cellular sheet side making contact with the wound bed. The diffusion of secreted growth factors would take place directly from cells to the wound bed without being impeded by a matrix. The cells are present at a high density in the dermal construct, which would aid in accelerated wound healing. The construct has a porous chitosan sponge base, which would allow gas exchange, and renders the dermal construct very flexible so that it would take the shape of the wound contours well, while having mechanical integrity. The viability of cells in the construct is greater than 90%. The dermal construct produces a high amount of vascular endothelial growth factor, from 42 ng to 31 ng in 24 h. The construct also produces high amounts of Interleukin-8 (IL-8), from 375 ng to 1065 ng in the first 24 h. Both VEGF and IL-8 have important roles in the healing of chronic diabetic ulcers.


Subject(s)
Fibroblasts/cytology , Skin Ulcer/therapy , Skin/cytology , Cell Survival/physiology , Cells, Cultured , Chitosan/chemistry , Diabetic Foot/therapy , Fibroblasts/metabolism , Humans , Interleukin-8/metabolism , Skin/metabolism , Skin/pathology , Tissue Engineering/methods , Vascular Endothelial Growth Factor A/metabolism , Wound Healing/physiology
20.
Am J Orthod Dentofacial Orthop ; 135(6): 737-48, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19524833

ABSTRACT

INTRODUCTION: This study was designed to evaluate patterns of stress generation in the temporomandibular joint after mandibular protraction, by using a 3-dimensional finite element method. The results of the initial investigation are reported here in Part 1. The effects of varying the construction bite are reported in Part 2. METHODS: A 3-dimensional computer-aided design model was developed from the magnetic resonance images of a growing boy (age, 12 years), by using I-DEAS NX (version 11.0, Siemens PLM Software, Plano, Tex). The model simulated mandibular protraction, with 5 mm of sagittal advancement and 4 mm of vertical opening. Stress distributions on the condylar neck, the glenoid fossa, and the articular disc in the anteroposterior and mediolateral directions were assessed. RESULTS: Tensile stresses were located on the posterosuperior aspects and compressive stresses on the anterior and anterosuperior aspects of the condylar head. Tensile stresses were found in the posterior region of the glenoid fossa near the attachment of the posterior connective tissues. CONCLUSIONS: These results suggest that, on mandibular protraction, the mandibular condyle experiences tensile stresses in the posterosuperior aspect that might help explain condylar growth in this direction. Similarly, on the glenoid fossa, tensile stresses are created in the region of posterior connective tissues; this might be correlated with the increased cellular activity in this region. Further study with variable vertical heights of the construction bites is needed.


Subject(s)
Finite Element Analysis , Imaging, Three-Dimensional/methods , Mandible/physiopathology , Mandibular Advancement/methods , Temporomandibular Joint/physiopathology , Cartilage, Articular/physiopathology , Child , Computer Simulation , Computer-Aided Design , Connective Tissue/physiopathology , Dental Occlusion, Centric , Humans , Magnetic Resonance Imaging , Male , Malocclusion, Angle Class II/therapy , Mandibular Condyle/physiopathology , Models, Biological , Retrognathia/therapy , Stress, Mechanical , Temporal Bone/physiopathology , Temporomandibular Joint Disc/physiopathology , Vertical Dimension
SELECTION OF CITATIONS
SEARCH DETAIL
...