Finite element stress analysis of stainless steel crowns.

BACKGROUND: Though stainless steel crowns (SSCs) have often been stated as the best restorative modality, there are limited studies demonstrating its efficacy in restoring the functional integrity of the primary dentition. Hence has arisen, the necessity to establish the supremacy of SSCs. AIM: Evaluation of the efficacy of SSC to with stand compressive (0°), shearing (90°), and torsional (45°) stress when used as a restorative material. SETTINGS AND DESIGN: The study design employed four finite element models, each with differing amounts of tooth structure, which were exported to ANSYS software and subjected to an average simulated bite force of 245N. MATERIALS AND METHODS: Four maxillary deciduous primary molars restored with SSCs (3M ESPE) were subjected to spiral computed tomography (CT) in order to obtain three-dimensional (3D) images, which were then converted into finite element models. They were each subjected to forces along the long axis of the tooth and at 45°and 90°. RESULTS: The maximal equivalent von Mises stress was demonstrated in the SSCs of all the models with only a minimal amount observed in the underlying dentine. In all situations, the maximal equivalent von Mises stress was well below the ultimate tensile strength values of stainless steel and dentine. CONCLUSION: Even at maximal physiologic masticatory force levels, a grossly destructed tooth restored with SSC is able to resist deformation.

Comparative evaluation in vitro of caries inhibition potential and microtensile bond strength of two fluoride releasing adhesive systems.

AIM: To evaluate and compare the caries inhibition potential and tensile bond strength of two commercially available fluoride releasing adhesive systems over conventional adhesive systems. METHODS: Artificial carious lesions were produced on the buccal surfaces of human molars and treated with experimental adhesive systems: Optibond Solo Plus(®), One-Up(®) Bond F Plus and G-BOND(®) (control). The caries inhibition potential and the tensile bond strength were measured at 24 h and 3 months, respectively. RESULTS: At 24 h and 3 months, Optibond Solo Plus(®) and One-Up(®) Bond F Plus had higher caries inhibition potential over the control group, which was statistically significant. At 3 months, no statistically significant difference was noted between the fluoride releasing adhesives. One-Up Bond F Plus had higher bond strength values than other groups which was statistically significant at 24 h, whereas at the end of 3 months, Optibond Solo Plus had higher bond strength values than other groups which were statistically significant. STATISTICS: The recorded values were statistically analysed using Paired t test, ANOVA followed by Post hoc Tukey's test. CONCLUSIONS: Fluoride releasing adhesive systems were effective in caries inhibition and showed comparatively higher bond strength values than the conventional adhesive systems in vitro.

A comparative study of color stability and fluoride release from glass ionomer cements combined with chlorhexidine.

BACKGROUND: Restoring carious teeth is one of the major treatment needs of young children. Glass ionomer cement (GIC) systems had become the most important dental restorative and luting materials for use in preschoolers, children and teenagers. Several attempts in developing GIC with antibacterial effects by addition of bactericides, such as chlorhexidine, have been reported. AIM: AIM of the study was to evaluate and compare the color and fluoride ion release of conventional and resin-modified GICs in combination with 1.25 and 2.5% chlorhexidine diacetate. MATERIALS AND METHODS: The control groups consisted of conventional GIC and resin-modified GIC. The experimental groups consisted of conventional and resin-modified GIC groups, consisting of 1.25 and 2.5% chlorhexidine. A total of six groups were included with each group being allotted 20 specimens for the evaluation of color stability and 10 specimens each were allotted for the evaluation of fluoride release. Color and fluoride release were recorded using spectrophoto-meter and fluoride selective electrode respectively at 24 hours 7 days and 1 month. RESULTS: Resin-modified GIC groups showed less color stability and better fluoride release at the end of the study compared to conventional GIC groups. CONCLUSION: There was no significant change in color and fluoride release between 1.25 and 2.5% conventional GIC and also between 1.25 and 2.5% resin-modified GIC combined with chlorhexidine diacetate at the end of the study. Conventional GIC showed better color stability and less fluoride release compared to resin-modified GIC. How to cite this article: Prabhakar AR, Pattanshetti K, Sugandhan S. A Comparative Study of Color Stability and Fluoride Release from Glass Ionomer Cements Combined with Chlorhexidine. Int J Clin Pediatr Dent 2013;6(1):26-29.

Comparison of Antibacterial Efficacy of Calcium Hydroxide Paste, 2% Chlorhexidine Gel and Turmeric Extract as an Intracanal Medicament and their Effect on Microhardness of Root Dentin: An in vitro Study.

AIM: To evaluate and compare the antibacterial efficacy of turmeric extract as an intracanal medicament against E. faecalis and its effect on the microhardness of root dentin in comparison with calcium hydroxide and 2% chlorhexidine gel. MATERIALS AND METHODS: One hundred and fourty dentin blocks were prepared from 70 extracted human single-rooted teeth and standardized. For antibacterial assessment, 120 blocks were infected for 21 days with E. faecalis (n = 24/group). Dentin blocks were treated with group I (Ca(OH)2), group II (2% chlorhexidine gel), group III (turmeric extract), group IV (saline) and group V (negative control). Dentin shavings were obtained in TSB at depth of 400 µm and plated to count CFUs at 24 hours, 3 and 7 days (n = 8/day). For microhardness assessment, eight samples of 2 mm thickness were prepared form four dentin blocks (n = 8/group). Following treatment with medicaments, microhardness test was performed at 24 hours, 3 and 7 days using Vickers hardness indentation machine at 400 µm from canal lumen. RESULTS: Complete inhibition of E. faecalis was observed with group II, followed by 64% with group I and 54% with group III which was statistically highly significant (p < 0.001). Highest effect on microhardness of root dentin was shown by group I, followed by group II and no effect was seen with group III which was statistically highly significant (p < 0.001). CONCLUSION: Turmeric extract has substantial antibacterial activity with no effect on microhardness of root dentine and hence has a potential to be used as intracanal medicament if its antibacterial activity could be enhanced. How to cite this article: Prabhakar AR, Swapnil T, Savita H, Sugandhan S. Comparison of Antibacterial Efficacy of Calcium Hydroxide Paste, 2% Chlorhexidine Gel and Turmeric Extract as an Intracanal Medicament and their Effect on Microhardness of Root Dentin: An in vitro Study. Int J Clin Pediatr Dent 2013;6(2):171-177.

Comparative evaluation of the remineralising effects and surface microhardness of glass ionomer cement containing grape seed extract and casein phosphopeptide - amorphous calcium phosphate: an in vitro study.

AIM: To evaluate and compare in vitro the remineralising effects and surface microhardness of glass ionomer cement (GIC), GIC containing grape seed extract and GIC containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP). METHODS: An in vitro study with 45 mandibular premolars with standardised class V cavities prepared on the buccal and lingual surfaces. Artificial caries-like lesions were created and teeth were randomly divided into 3 groups of 15 teeth each. Each tooth was sectioned longitudinally into buccal and lingual halves; lingual half was used as control and the other as the test specimen. Axial longitudinal sections of the control specimens were analysed under polarised light microscopy. The experimental halves were restored with 3 materials. Group I: glass ionomer cement (GIC), Group II: 10% (w/w) grape seed extract and GIC (GSGIC), Group III: 10% (w/w) casein phosphopeptide-amorphous calcium phosphate (Recaldent) and GIC (CPPGIC). The restored tooth specimens were exposed to pH cycling for 28 days and analysed again for remineralisation under polarised microscopy. For the second part of the study, 60 cylindrical specimens (20 each) were made using standardised brass moulds and the three experimental materials. The specimens were immersed individually in de-ionised water. After 7 days of immersion, 10 specimens from each group were subjected to microhardness measurements and repeated on the remaining specimens at the end of 30 days. STATISTICS: One way ANOVA and post-hoc Tukey's test were used for statistical analysis. RESULTS: CPPGIC showed the greatest remineralisation followed by GSGIC and least for GIC. Comparisons of microhardness between the three groups were not statistically significant. CONCLUSION: Grape seed extract and CPPACP can be used for remineralisation of damaged dentine and their incorporation into GIC does not compromise the microhardness properties significantly.

Comparative evaluation of the length of resin tags, viscosity and microleakage of pit and fissure sealants - an in vitro scanning electron microscope study.

INTRODUCTION: In this era of preventive dentistry, many techniques are available for prevention of caries, such as plaque control, use of systemic and local fluorides and pit and fissure sealants. The rationale of pit and fissure sealants is that, when they are applied into the caries prone fissures, they penetrate and seal them from the oral environment. This study aims to correlate the relationship between the viscosity of the sealant, resin tag length and microleakage. MATERIALS AND METHODS: 30 third molars were selected for study. The teeth were randomly divided into 3 groups. Group E: Embrace wetbond, H: Helioseal, G: Guardian seal. Teeth were cleaned with pumice prophylaxis and pretreated with acid etching and bonding agent. The respective pit and fissure sealants were applied. Teeth were placed in 1% methylene blue dye and sectioned mesio-distally into two halves. These were used to assess the microleakage using stereomicroscope and resin tag length using SEM. Viscosity was assessed using Brooke's field viscometer. RESULTS: Viscosity was lowest for Embrace wetbond and highest for Guardian seal. Microleakage scores were highest with Guardian seal and lowest with Embrace wetbond. Resin tag lengths were longer with Embrace wetbond as compared to other groups. There is a definite negative correlation between viscosity, resin tag length and microleakage. Lower the viscosity, the longer were the resin tags and the microleakage decreased. Embrace wetbond pit and fissure sealant had lowest viscosity, longest resin tag length and lowest microleakage scores. CONCLUSION: Embrace wetbond appears to be compatible with residual moisture and ideal for use in children, where isolation is a problem.

Subcutaneous zygomycosis: report of 10 cases from two institutions in North India.

BACKGROUND: Subcutaneous zygomycosis is an uncommon condition observed in tropics. Few series have been published, particularly from the northern regions of India. OBJECTIVES: The aim of this study was to describe clinical, investigative and therapeutic details in subcutaneous zygomycosis observed in two teaching hospitals in Delhi. PATIENTS AND METHODS: Ten patients seen over a period of 10 years (1999-2009) form the material for this report. RESULTS: There were four children and six adults. In four children, the presentation was a subcutaneous localized mass or gradually spreading plaque. In the others, it was observed over nasal region of face, spreading inward into mucosal sites and paranasal sinuses, and outward to the contiguous areas. Regional lymphadenopathy was present in two with facial lesions. Majority showed a granulomatous infiltrate with admixture of other cells, mainly eosinophils. Aseptate or poorly septate hyphae were observed in seven. In one patient in whom no hyphae were observed, there was dense perivascular inflammation. Organisms were cultured from four patients, Basidiobolus ranarum in two and Syncephalastrum racemosum in two. The main therapy used was a saturated solution of potassium iodide (KI). Four received only KI of which two attained cure after 3 months and 9 months respectively, and the other two showed signs of regression. In one boy subsidence was associated with reduced circumference of thigh. Ketoconazole or itraconazole was given with KI to hasten regression when response was slow or there were side-effects to KI. CONCLUSION: Awareness and early recognition will prevent disfigurement produced by advanced disease, misdiagnosis and unnecessary surgical intervention.

Diagnostic applications of saliva in dentistry.

BACKGROUND: The use of saliva to identify individuals with disease and to follow the progress of the affected individual has attracted the attention of numerous investigators. Its noninvasive method of collection, simplicity, and cost effectiveness make it a useful tool not only to the general practitioner but also to the pediatric dentist. AIM: The aim of this paper is to provide the clinician with a comprehensive review of the diagnostic uses of saliva in dentistry.

A comparison of bitewing radiography and fibreoptic illumination as adjuncts to the clinical identification of approximal caries in primary and permanent molars.

A clinical study was conducted on 150 approximal surfaces which were positive for caries by fibreoptic transillumination (FOTI), and these approximal surfaces were examined with bitewing radiography. Of these 54.7% and 41.3% were diagnosable through bitewing radiography and clinical examination respectively. And it was clearly understood that FOTI was a reliable method in detecting approximal carious lesions.