An In Vitro Study on the Effects of Post-Core Design and Ferrule on the Fracture Resistance of Endodontically Treated Maxillary Central Incisors.

BACKGROUND: Endodontically treated teeth have significantly different physical and mechanical properties compared to vital teeth and are more prone to fracture. The study aims to compare the fracture resistance of endodontically treated teeth with and without post reinforcement, custom cast post-core and prefabricated post with glass ionomer core and to evaluate the ferrule effect on endodontically treated teeth restored with custom cast post-core. MATERIALS AND METHODS: A total of 40 human maxillary central incisors with similar dimensions devoid of any root caries, restorations, previous endodontic treatment or cracks were selected from a collection of stored extracted teeth. An initial silicone index of each tooth was made. They were treated endodontically and divided into four groups of ten specimens each. Their apical seal was maintained with 4 mm of gutta-percha. Root canal preparation was done and then post core fabrication was done. The prepared specimens were subjected to load testing using a computer coordinated UTM. The fracture load results were then statistically analyzed. One-way ANOVA was followed by paired t-test. RESULTS: 1. Reinforcement of endodontically treated maxillary central incisors with post and core, improved their fracture resistance to be at par with that of endodontically treated maxillary central incisor, with natural crown. 2. The fracture resistance of endodontically treated maxillary central incisors is significantly increased when restored with custom cast post-core and 2 mm ferrule. CONCLUSION: With 2 mm ferrule, teeth restored with custom cast post-core had a significantly higher fracture resistance than teeth restored with custom cast post-core or prefabricated post and glass ionomer core without ferrule.

Agenesis of multiple primary and permanent teeth unilaterally and its possible management.

Oligodontia is the agenesis of numerous teeth (more than six teeth). Agenesis of teeth in primary and permanent dentition is a rare incidence and very few are reported in the dental literature. Although the etiology of congenital agenesis of teeth is unclear, several factors such as a tendency toward genetic predilection, metabolic disorders, trauma, infection, radiation or idiopathic reasons are found to be responsible. Available literature reports agenesis most often of third molars, maxillary lateral incisors, mandibular central and lateral incisors, and mandibular second premolars in decreasing order of frequency of occurrence. Males are more often affected than females. Maxillary primary teeth are more often found affected by agenesis than mandibular primary teeth. Available literature reports missing teeth to be found unilaterally or orbilaterally with a predisposition toward a similar phenomenon occurring in the permanent dentition. In congenital agenesis impaired growth of the alveolar process, reduced lower facial height, speech impairment, deep bite, restriction in the movement of the tongue due to ankyloglossia, asymmetry of the affected side of the face are clinical features evident. There has been no report of complete agenesis of primary and permanent teeth in a whole mandibular quadrant in conjunction with the absence of maxillary second and third molars on the affected side. Here, we report an incidence of a rare occurrence of complete agenesis of more than 10 primary and permanent teeth, unilaterally, in the right mandibular quadrant, in a child of 10 years presenting with a chief complaint of several missing primary teeth and difficulty in speech due to its complete absence. Treatment strategies included various orthodontic and restorative procedures to improve esthetics and function. The orthodontic procedures involved expansion of the narrow maxillary arch to obtain a functionally adapted occlusion and creation of space for future alignment, and uprighting and protecting maxillary right posteriors to accommodate the tongue and rectify speech. Restorative procedures involved fabrication of a removable partial denture as a temporary measure to restore missing teeth, improve esthetics, give lingual support to the lower lip, prevent further downward growth of the right maxillary ridge and to prevent supra eruption of these teeth.

Vibrational and UV spectra, first order hyperpolarizability, NBO and HOMO-LUMO analysis of 4-chloro-N-(2-methyl-2,3-dihydroindol-1-yl)-3-sulfamoyl-benzamide.

In this work, the vibrational spectral analysis was carried out by using FT-Raman and FT-IR spectroscopy in the range 4000-100 cm(-1) and 4000-400 cm(-1), respectively, for 4-chloro-N-(2-methyl-2,3-dihydroindol-1-yl)-3-sulfamoyl-benzamide (C16H16O3N3SCl) molecule. Theoretical calculations were performed by density functional theory (DFT) method using 6-31G(d,p) and 6-311G(d,p) basis sets. The complete vibrational assignments of wavenumbers were made on the basis of potential energy distribution (PED). The results of the calculations were applied to simulated spectra of the title compound, which show excellent agreement with observed spectra. The frontier orbital energy gap and dipole moment illustrates the high reactivity of the title molecule. The first order hyperpolarizability (ß0) and related properties (µ, α, and Δα) of the molecule were also calculated. Stability of the molecule arising from hyperconjugative interactions and charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The UV-vis spectrum of the compound was recorded in the region 200-400 nm in ethanol and electronic properties such as excitation energies, oscillator strength and wavelength were calculated by TD-DFT/B3LYP method. Molecular electrostatic potential (MEP) and HOMO-LUMO energy levels are also constructed. The thermodynamic properties of the title compound were calculated at different temperatures.

Vibrational spectra, first order hyperpolarizability, NBO, Fukui function and HOMO-LUMO analysis of 2-[4-(1,3-benzodioxol-5-ylmethyl)-1-piperazinyl] pyrimidine.

In this work, the vibrational spectral analysis was carried out by using FT-Raman and FT-IR spectroscopy in the range 4000-100cm(-1) and 4000-400cm(-1) respectively, for 2-[4-(1, 3-benzodioxol-5-ylmethyl)-1-piperazinyl] pyrimidine(BDPP) molecule. Theoretical calculations were performed density functional theory (DFT) method using 6-31G(d,p) and 6-311G(d,p) basis sets. The assignments of vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the scaled quantum mechanical force field (SQMFF) methodology. The results of the calculations were applied to simulated spectra of the title compound, which show excellent agreement with observed spectra. The frontier orbital energy gap and dipole moment illustrates the high reactivity of the title molecule. The first order hyperpolarizability (ß0) and related properties (µ, α and Δα) of the title molecule were also calculated. Stability of the molecule has been analyzed by natural bond orbital (NBO) analysis. Global reactivity and local reactivity descriptors of the title molecule have been calculated. Mulliken population analyses on atomic charges of the title compound have been calculated. Finally, molecular electrostatic potential (MEP) and HOMO-LUMO energy levels have been performed.

Electronic absorption, vibrational spectra, nonlinear optical properties, NBO analysis and thermodynamic properties of N-(4-nitro-2-phenoxyphenyl) methanesulfonamide molecule by ab initio HF and density functional methods.

In this work, the vibrational spectral analysis was carried out by using FT-Raman and FT-IR spectroscopy in the range 4000-100 cm(-1) and 4000-400 cm(-1), respectively, for N-(4-nitro-2-phenoxyphenyl) methanesulfonamide molecule. Theoretical calculations were performed by ab initio RHF and density functional theory (DFT) method using 6-31G(d,p) and 6-311G(d,p) basis sets. The complete vibrational assignments of wavenumbers were made on the basis of potential energy distribution (PED). The results of the calculations were applied to simulated spectra of the title compound, which show excellent agreement with observed spectra. The frontier orbital energy gap and dipole moment illustrates the high reactivity of the title molecule. The first order hyperpolarizability (ß0) and related properties (µ, α and Δα) of the molecule were also calculated. Stability of the molecule arising from hyperconjugative interactions and charge delocalization were analyzed using natural bond orbital (NBO) analysis. The results show that electron density (ED) in the σ(*) and π(*) anti-bonding orbitals and second order delocalization energies (E2) confirm the occurrence of intramolecular charge transfer (ICT) within the molecule. UV-vis spectrum of the compound was recorded in the region 200-500 nm in ethanol and electronic properties such as excitation energies, oscillator strength and wavelength were calculated by TD-DFT/B3LYP, CIS and TD-HF methods using 6-31G(d,p) basis set. Molecular electrostatic potential (MEP) and HOMO-LUMO energy levels are also constructed. The thermodynamic properties of the title compound were calculated at different temperatures and the results reveals the heat capacity (C), and entropy (S) increases with rise in temperature.