ABSTRACT
The hard tissue erbium lasers have the capability to prepare enamel, dentin, caries, cementum and bone in addition to cutting soft tissue.The present study is aimed at evaluating the tensile bond strength a self etching restorative system, on superficial and deep dentin, after cutting the tooth with bur or Er:YAG laser. Methods: Sixty sound extracted human premolars were used in the study. These teeth were then randomly divided into two groups of thirty teeth each. Group 1- Bur cut, cut using diamond cutting disc and Group 2- Laser cut, cut using Er:YAG laser calibrated with 200mJ/10HZ/2.0W under 4ml/min water spray. These were then divided into two more subgroups of fifteen teeth as superficial and deep dentin sub groups. Specimens were coated with bonding agent followed by a microhybrid resin composite (SUREFILL,DENTSPLY). The specimens were then debonded in tension by mounting it on a universal testing machine (Instron Type 4204 Co.USA) and specimen SEM analysis of surfaces was done. Results: Bur cut superficial dentin showed maximum tensile bond strength (22.86 MPa) while bur cut deep dentin showed the least tensile bond strength (15.8MPa),Laser cut superficial dentin and deep dentin showed almost similar bond strength -19.18 MPa and 19.94MPa respectively. Conclusion: The superficial dentin produced better bond strength and results than deep dentin. Surface treatment by Er:YAG laser hampered the adhesion of self etching adhesive systems in both superficial and deep dentin.
ABSTRACT
The objective of the research was to formulate and evaluate selegiline hydrochloride loaded chitosan nanoparticles for the Parkinson's therapy in order to improve its therapeutic effect and reducing dosing frequency. Taguchi method of design of experiments (L9 orthogonal array) was used to get optimized formulation. The selegiline hydrochloride loaded chitosan nanoparticles (SHPs) were prepared by ionic gelation of chitosan with tripolyphosphate anions (TPP) and tween 80 as surfactant. The SHPs had a mean size of (303.39 ± 2.01) nm, a zeta potential of +32.50mV, and entrapment efficiency of SHPs was 86.200 ± 1.38%. The in vitro drug release of SHPs was evaluated in phosphate buffer saline (pH 5.5) using goat nasal mucosa and found to be 82.529% ± 1.308 up to 28 h. Release kinetics studies showed that the release of drug from nanoparticles was anomalous (non-fickian) diffusion indicating the drug release is controlled by more than one process i.e. superposition of both phenomenon, the diffusion controlled as well as swelling controlled release. SHPs showed good stability results as found during stability studies at different temperatures as mentioned in ICH guidelines. The results revealed that selegiline hydrochloride loaded chitosan nanoparticles are most suitable mode of delivery of drug for promising therapeutic action.
O objetivo da pesquisa foi formular e avaliar nanopartículas de quitosana contendo cloridrato de selegilina para terapia do Parkinson, a fim de melhorar o seu efeito terapêutico e reduzir a frequência de dosagem. Método de Taguchi, de planejamento experimental, (L9 matriz ortogonal) foi usado para obter a formulação otimizada. As nanopartículas de quitosana contendo cloridrato de selegilina (PCHs) foram preparadas por gelificação iônica de quitosana com ânions tripolifosfato (TPP) e Tween 80 como tensoativo. As PCHs apresentaram tamanho médio de (303.39 ± 2,01) nm, potencial zeta de +32.50 mV e eficiência de encapsulação de 86.200±1,38%. A liberação do fármaco in vitro foi avaliada em solução salina de tampão fosfato (pH 5,5), usando a mucosa nasal de cabra e o resultado encontrado foi de 82.529% ± 1.308, acima de 28 h. Estudos de cinética de liberação mostraram que a liberação do fármaco das nanopartículas foi por difusão anômala (não fickiana), indicando que é controlada por mais de um processo, ou seja, a superposição dos fenômenos de difusão controlada e intumescimento. As PCHs mostraram resultados de boa estabilidade, encontrada durante os estudos de estabilidade em temperaturas diferentes, como mencionado em diretrizes do ICH. Os resultados revelaram que o sistema de nanopartículas de quitosana contendo cloridrato de selegilina é o mais adequado sistema de liberação de fármacos de ação terapêutica promissora.