Evaluation of stability of three different mini-implants, based on thread shape factor and numerical analysis of stress around mini-implants with different insertion angle, with relation to en-masse retraction force

ABSTRACT Objectives: Assess the stability of three different mini-implants, based on thread shape factor (TSF), and evaluate stresses at the mini-implant site and surrounding cortical bone on application of retraction force, at two different insertion angles. Methods: Mini-implants of three different diameters (M1 - Orthoimplant, 1.8mm), (M2 - Tomas, 1.6mm) and (M3 - Vector TAS, 1.4mm) and length of 8mm were used. Using scanning electronic microscopy, the mean thread depth, pitch and relationship between the two (TSF) were calculated. The mini-implants were loaded into a synthetic bone block and the pull-out strength was tested. One way ANOVA and Tukey post-hoc tests were used to compare the pull-out strength of mini-implants. P values < 0.05 were considered statistically significant. Finite element models (FEM) were constructed with insertion angulation at 90° and 60°, with retraction force of 150 g. The results were analyzed using ANSYS software. Results: Statistically significant difference was found among all the three mini-implants for thread depth and pitch (< 0.001). Statistically significant higher pull-out force value was seen for Orthoimplant. The stress distribution level in mini-implant and surrounding bone was observed to be smaller for Orthoimplant. Conclusion: Orthoimplant mini-implants have more favorable geometric characteristics among the three types, and less stress with 90°angulation.

RESUMO Objetivos: Avaliar a estabilidade de três diferentes tipos de mini-implantes, com base no fator formato da rosca (thread shape factor, TSF), e avaliar a tensão no local de inserção e no osso cortical ao redor dos mini-implantes inseridos com dois ângulos diferentes, durante a aplicação de força para retração. Métodos: Foram usados três diferentes diâmetros de mini-implantes, sendo eles 1,8 mm (M1, ORTHO Implant), 1,6 mm (M2, Tomas) e 1,4 mm (M3, Vector TAS), todos com comprimento de 8 mm. Por meio da microscopia eletrônica de varredura, foram calculados a profundidade da rosca, o passo da rosca (distância entre os filetes da rosca) e a relação entre os dois (TSF). Para realização do teste de tração (pull-out), os mini-implantes foram inseridos em um bloco de osso sintético. Os testes ANOVA de uma via e post-hoc de Tukey foram usados para comparar as forças de resistência à tração dos mini-implantes, considerando-se estatisticamente significativos valores de p< 0,05. Modelos de elementos finitos (MEF) foram gerados com ângulos de inserção dos mini-implantes a 90° e 60°, com força de retração em 150g. Os resultados foram analisados usando-se o software ANSYS. Resultados: Diferenças estatisticamente significativas foram encontradas entre os três mini-implantes quanto à profundidade da rosca e o passo da rosca (p< 0,001). O ORTHO Implant apresentou a maior força de resistência à tração, com significância estatística. O nível de distribuição das tensões no mini-implante e no osso circundante também foi menor para o ORTHO Implant. Resultados: Entre os diferentes tipos de mini-implantes analisados, o ORTHO Implant apresentou as características geométricas mais favoráveis e a menor tensão com o ângulo de inserção de 90°.

Efficacy and Tolerability of Tianeptine Versus Escitalopram in Patients with Irritable Bowel Syndrome: A Hospital based, Randomized Comparative Study

Introduction: The fallopian Tube or the oviduct has beennamed after Gabrielis Fallopius, who was the first to describethe tubes very accurately. It is one of the commonest surgicalspecimens received in the histopathological laboratory. It isthe commonest cause of infertility and inflammatory diseases.Malignancy of the fallopian tube is rarely encountered. Thepresent study was undertaken with the following objectivesto evaluate the histological patterns of the fallopian tube insurgically resected specimens and to determine its relationshipwith uterine or ovarian pathology.Material and Methods:A total number of 309 specimensof Fallopian tube were obtained from the patients whounderwent pan hysterectomy with salpingectomy andsalpingo-oophorectomies in Assam Medical College andHospital during the period from October 2016 to September2018. The clinical datas along with gross and microscopicfindings were studied. Incidence and prevalence of variouslesions were calculated.Results: In our study 10cases (3%) had been marked asunremarkable. 77.4% were diagnosed as Chronic Salpingitis,8.95% as Hydrosalpinx and 2.47% as Ectopic Pregnancy. Theother cases comprised mainly of Haematosalpinx andnormalhistologyConclusion: Fallopian tubes can present with differentpathological findings. Malignancies of the Fallopian Tube areuncommon but it has to be examined properly to exclude aprecursor Tubal Pathology