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1.
Front Bioeng Biotechnol ; 10: 798988, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35557860

RESUMO

Background: Finite element analysis (FEA) is one of the best methods for evaluating the stress distribution of restorations, such as fixed partial dentures. The development of resin cement has transformed prosthesis bonding and retention properties. Resin-bonded fixed partial dentures (RBFPD) have been considered minimally invasive treatment options for the prosthetic rehabilitation of single missing teeth. Objectives: The aim of this study was to evaluate the stress load and distribution in four different designs of acid-etched RBFPDs using FEA. Materials and Methods: The designs included standard tooth preparation principles and additional features. The first premolar and first molar abutments replaced the missing second premolar. Designs 1, 2, 3, and 4 included (1) lingual wings and occlusal rests; (2) wings and proximal slices; (3) wings, rests, and grooves; and (4) wings, rests, grooves, and occlusal coverage. The prepared models were restored with RBFPDs. A load of 100 N was applied to the central groove of the pontic to simulate occlusal forces. The materials used in the models were considered to be isotropic, homogeneous, and linearly elastic. FEA was used to reveal stresses acting on the abutment, bone, and connector in all prosthesis designs. Results: The stresses transmitted to the abutment and bones were lowest for design 3, using wings, rests, and grooves. The stresses acting on the connector were the weakest in design 2. The stresses transmitted to the abutment and bone were highest in designs 1 and 4. The stresses transmitted to the connector were highest in design 3. Conclusion: The wings, rests, and grooves design is possibly the ideal and conservative tooth preparation design to receive a posterior RBFPD. This design transmits less stress to the abutments and less bone resorption in the FEA. It is most likely to be successful in the clinical provision and ensures the longevity of the prosthesis.

2.
BMJ Case Rep ; 15(4)2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35365468

RESUMO

A woman in her 70s with vague gastrointestinal (GI) symptoms and unintentional weight loss was referred to endoscopy clinic for investigation and consideration of GI malignancy. CT of the thorax, abdomen and pelvis showed a suspicious mass in the oesophago-gastric junction with a lytic lesion on S1-S2 sacrum. A subsequent upper GI endoscopy revealed two raised, ulcerated tumours on the lesser curvature of the stomach. By the time an MRI of the whole spine was done which revealed multiple metastases involving thoracic, lumbar and sacral skeleton, she had developed leg weakness and paraesthesias, consistent with the imaging findings. A positron emission tomography/CT scan further confirmed the above findings. The initial working diagnosis was primary GI tumour with bony metastases. However, she was later referred to the haematology team after the immunohistochemistry of the tumour showed that it was of a plasma cell origin (CD138 positive) associated with lambda light chain deposits. Serum-free light chain showed a raised lambda light chain of 272 mg/L and kappa light chain of 11.3 mg/L and involved/uninvolved light chain ratio of 24. Bone marrow biopsy confirmed a plasma cell myeloma with moderate disease burden. Monoclonal lambda chains were demonstrated on immunofixation but negative on serum protein electrophoresis and hence a diagnosis of oligosecretory myeloma with GI involvement was made. Subsequent management involved physiotherapy, pain management and chemotherapy, where this woman was commenced on Velcade (generically known as bortezomib), thalidomide and dexamethasone and she continued to experience clinical and biochemical improvement.


Assuntos
Mieloma Múltiplo , Feminino , Trato Gastrointestinal , Humanos , Cadeias Leves de Imunoglobulina , Cadeias kappa de Imunoglobulina/análise , Cadeias lambda de Imunoglobulina , Mieloma Múltiplo/complicações , Mieloma Múltiplo/diagnóstico
3.
J Popul Ther Clin Pharmacol ; 28(1): 14-23, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34476914

RESUMO

BACKGROUND: Regular visits to the health care providers can develop a relationship that can extend beyond the physical health alone as the patient is transiting towards older age, adapting to changes in physical health, emotional health, and social connections. Apart from limiting access to health care services, the attitudes, beliefs, comfort level of the treating doctors towards the geriatric patients can motivate or demotivate them to access dental care. AIM: To explore the Saudi Arabian undergraduate students perception of geriatric patients and identify potential barriers that prevent the utilization of their dental appointment. METHODS: A close-ended questionnaire with one question and eight reasons was administered to the fifth year clinical students. The students were requested to specify their agreement with each question on a 5-point Likert scale. Among the barriers presented, each reason's approval was expressed as the percentage of the total number of responses. In addition, the gender comparison of mean scores was made, and an independent sample t-test was used to analyze the statements agreed by the students. All analyses were performed using Statistical Package of Social Sciences (SPSS) version 21.0 (IBM, USA) with the probability of statistical significance at 0.05 level. RESULTS: Fifty-one students recorded their perceptions on the questionnaire administered during their clinical posting in the fifth year of the geriatric dental education program. It was concluded that students believed that geriatric patients give overwhelming importance to other problems with minor importance to oral health care. In addition, gender comparison was more evident as the percentage expressed was more in females. CONCLUSIONS: There is a need for more clinical exposure of geriatric patients during their clinical postings. Student's acquaintance with didactic and clinical settings appears to be a critical element towards positive knowledge and attitude towards the geriatric population.


Assuntos
Atitude do Pessoal de Saúde , Estudantes de Odontologia , Idoso , Estudos Transversais , Feminino , Humanos , Percepção , Arábia Saudita , Inquéritos e Questionários
4.
J Pharm Bioallied Sci ; 13(Suppl 1): S660-S663, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34447175

RESUMO

PURPOSE: The purpose of the study was to assess the effectiveness of erbium:yttrium-aluminum-garnet (Er:YAG) laser surface pretreatment at various pulse durations of exposure on increasing the tensile bonding strength of permanent soft relining material and acrylic resin. MATERIALS AND METHODS: Polymethyl methacrylate resin samples were fabricated and grouped as comparison group (no laser surface pretreatment) and three test groups (received Er:YAG laser surface pretreatment at various pulse durations of 10 s, 20 s, and 30 s) for bonding with the permanent soft relining material, Molloplast B. Following the surface pretreatment, the samples were tested for tensile stress using a universal testing machine. Loads at the point of failure were noted and the tensile bond strength values were obtained. Parametric tests of one-way-ANOVA and Tukey's post hoc tests were done. RESULTS: The highest tensile bonding strength was recorded in Group C, and the control group recorded the lowest bonding strength. CONCLUSION: Er:YAG laser surface pretreatment at 10 Hz, 3 W, and 300 mJ for 30 s improved the bonding strength of the permanent soft relining material to heat-processed acrylic resin material.

5.
Langmuir ; 35(13): 4672-4681, 2019 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-30832479

RESUMO

Incorporation of multifunctional inorganic additives into the commercial polymers still stands as the most captivating and effective way to realize new-generation electronic components. Here, we introduce a simple, cost-effective, and environmentally benign method to covalently functionalize graphene oxide (GO) with vinyl- and aminopropyl-functionalized hybrid silica spheres with a polyhedral oligomeric silsesquioxane (POSS)-siloxane composition. The reaction has been carried out in a mixture of ethanol and water (used as a medium) at ambient conditions with silane precursors. Later, the synthesized hybrid material has been tested for its dielectric properties after blending with syndiotactic polystyrene, a commercially available insulating semicrystalline polymer. It was observed that the dielectric constant decreases with the addition of GOPOSS up to 1.85 with a dielectric loss of 0.02 at 5 GHz. Significant improvements in the thermal properties of the composites were verified with minimal filler loading.

6.
Contemp Clin Dent ; 10(4): 658-663, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-32792826

RESUMO

Purpose: The aim of the study was to evaluate the effect of incorporation of organically modified nanoclay in 1%, 3%, and 5% by weight on the flexural strength, surface hardness, and linear polymerization shrinkage of heat cure denture base material. Materials and Methods: One hundred and twenty specimens of heat-polymerized acrylic resin were fabricated. The specimens were divided into four groups (n = 10) coded I to IV. Group I was the control group (unmodified acrylic resin specimens). The specimens of the remaining three groups were reinforced with nanoclay (organically modified montmorillonite) nanoparticles to achieve loadings of 1%, 3%, and 5% by weight. The resulting nanocomposites were subjected to mechanical testing and were characterized using X-ray diffraction, scanning electron microscope, and transmission electron microscope. Results: The statistical analysis showed that there was no significant increase in flexural strength within and between the groups. The most significant increase in surface hardness was observed between Group I (control) and Group II (1% nanoclay). Linear polymerization shrinkage of the specimens showed a significant decrease in the control and all the experimental groups. Conclusion: Addition of 1 wt% nanoclay to polymethyl methacrylate heat cure denture base material could enhance the surface hardness and reduce the linear polymerization shrinkage of the resin. However, there was no significant increase in flexural strength of the resulting nanocomposite.

8.
J Indian Prosthodont Soc ; 17(1): 74-79, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28216849

RESUMO

To assess the implant stability during different stages of healing in an immediate loaded implant soon after extraction. A 73-year-old female came with a chief complaint of bad smell and irritation in her lower front gum region. On examination, she was found to be completely edentulous in the maxillary arch and partially edentulous in the mandibular arch with only the canines present bilaterally. The posterior mandibular ridge was severely resorbed and hence could not be treated with a conventional mandibular complete denture. Considering the age of the patient and the preference of only a single surgical visit, we decided to plan for a conventional maxillary denture against an implant supported mandibular overdenture with two implants placed immediately after extraction of canines. The stability of these implants was assessed during the early phases of healing with the help of a resonance frequency analysis method (RFA) using Osstell ISQ™. During the healing phase, implant stability quotient (ISQ) values decrease by 4-5 values after installation with the lowest values at the 1st week postplacement. Following this, the ISQ values increased steadily for all implants up to 16 weeks. No significant differences were noted over time. At placement, the mean ISQ values at 33 and 43 regions were 74 and 75.2, respectively. The mean lowest ISQ values recorded at the 1st week were 58.8 and 65.4, respectively. At 16 weeks, the mean ISQ values were 70.5 and 67.9, respectively. The survival of such immediately placed implants, which are later used as overdenture supported implants, are highly predictable when the surgical and prosthetic part is done meticulously. However, there needs future studies oriented to understand better the healing pattern of immediately placed implants in extraction sockets, which would guide the clinician with the optimal loading time.

9.
Clin Case Rep ; 4(12): 1082-1087, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27980737

RESUMO

Complete dentures are poorly tolerated in patients with xerostomia. A salivary reservoir can be incorporated into a denture that provides slow, sustained, and continuous release of salivary substitute. This article describes a simple, cost-effective, and innovative technique of fabrication and designing of functional maxillary salivary reservoir complete denture.

10.
Indian J Dent Res ; 27(6): 672-676, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28169270

RESUMO

To tackle a large midline diastema and generalized spacing existing before extraction often poses a challenge to the treating prosthodontist. The situation becomes even more complicated if the patient is a teenager, with multiple missing teeth, associated deep bite and where the jaw bone growth has not yet been completed. Possible treatment options would include a removable prosthesis, a fixed partial denture or an implant supported prosthesis. Treating such cases with a simple removable prosthesis cannot be justified if a deep bite existed which would result in posterior disocclusion. Also a conventional fixed partial denture or closure of the diastema with light cure composite (LCC), would result in a seemingly large tooth, which would be unaesthetic in appearance. Implant supported prosthesis is a possibility, if the patient's jaw bone growth has been completed. Another simple non-invasive solution to this problem would be to fabricate a non-rigid connector using loops. This presentation describes the procedure for fabrication of an interim loop connector for a 16 year old female patient who had lost one of her maxillary central incisors as a result of trauma. Patient also had multiple spacing in the maxillary anterior teeth and an associated deep bite. Her cephalogram revealed that she had a Class III skeletal pattern. A permanent treatment at this stage was not possible due to ontoward mandibular growth pattern as revealed on the cephalogram. Hence to dodge all these problems, a simple and non-invasive treatment using loop connectors was chosen till the growth period was completed.


Assuntos
Planejamento de Dentadura , Prótese Parcial Fixa , Prótese Parcial Removível , Diastema/terapia , Adolescente , Cefalometria , Retenção de Dentadura , Feminino , Humanos , Incisivo , Sobremordida , Fotografia Dentária , Extração Dentária
11.
ACS Omega ; 1(6): 1220-1228, 2016 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-31457190

RESUMO

Two-dimensional materials play a vital role in the current electronic industry in the fabrication of devices. In the present work, we have exfoliated and stabilized the insulating hexagonal boron nitride (hBN) by means of a polymer-assisted liquid-phase technique. Further, the highly viscous ink of hBN was prepared, and its printability on various commercially available substrates was studied. The morphology of the printed patterns reveals the layered arrangement of hBN. The various electrical and dielectric characterizations, carried out on a metal-insulator-metal capacitor, testified its potential applications in various fields of printed electronics.

12.
ACS Appl Mater Interfaces ; 7(34): 19474-83, 2015 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-26287385

RESUMO

Homogeneously dispersed hybrid silica/syndiotactic polystyrene composites were investigated for low-κ dielectric applications. The composites were prepared by a solution blending method, and their microstructures were analyzed by SEM, TEM, and AFM. Crystallization and phase transformation behavior of sPS were investigated using differential scanning calorimetry and wide-angle X-ray diffraction. These composites exhibited improved thermal stability and reduced thermal expansion coefficients. Promising dielectric properties were observed for the composites in the microwave frequency region with a dielectric constant (κ = 1.95) and loss (tan δ = 10(-4)) at 5 GHz.

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