Evaluation of the surface of root canal walls after utilization of endodontic rotary systems: SEM study

The objective of the present study was to determine, by scanning electron microscopy, the aspect of root canal walls after utilization of different rotary instrumentation systems for root canal preparation. Forty-two single-rooted and straight teeth were divided into six groups, whose root canals were prepared using the following rotary systems: groups 1 and 2 - Quantec; groups 3 and 4 - Pow-R; groups 5 and 6 - Profile. Irrigation was performed with 2.5% sodium hypochlorite solution in all groups, while only groups 2, 4 and 6 received a final flush with EDTA. Data were analyzed by non-parametric Kruskal-Wallis and Miller tests. Removal of the smear layer and other debris was more effective in the groups receiving EDTA as final irrigant. The Profile system showed the best cleaning, generating only a minimum smear layer, with a significant difference being observed compared to the Pow-R system (pO objetivo do presente estudo foi avaliar por meio de microscopia eletrônica de varredura, o aspecto superficial de paredes de canais radiculares apos uso de sistemas rotatórios de instrumentação endodôntica. Quarenta e dois dentes unirradiculados e com canais retilíneos foram divididos em seis grupos experimentais. Foram preparados utilizando-se os seguintes sistemas: Grupos 1 e 2 - Sistema Quantec; grupos 3 e 4 - Sistema Pow-R; grupos 5 e 6 - Sistema Profile. A irrigação foi realizada com solução de hipoclorito de sódio a 2.5% em todos os grupos durante a instrumentação. Apenas nos grupos 2, 4 e 6 foi realizada toalete final dos canais com solução de EDTA. O dados foram analisados pelos testes não paramétricos de Kruskal-Wallis e Miller. Foi observada maior remoção de smear layer e outros resíduos nos grupos onde foi realizada a toalete final com solução de EDTA. O sistema Profile mostrou melhor resultado, gerando menor quantidade de resíduos, com diferença significante quando comparado com o sistema Pow-R(

Experimental periodontal disease treatment by subgingival irrigation with tetracycline hydrochloride in rats

OBJECTIVE: The aim of this study was to compare subgingival irrigation with tetracycline hydrochloride (TTC-HCL) as adjunctive treatment to scaling and root planning (SRP) on induced periodontitis in rats. MATERIAL AND METHODS: In 60 rats, periodontal disease was ligature-induced at the mandibular left first molar. After 7 days, the ligature was removed and all animals were submitted to SRP, and divided into 2 groups according to the following treatment: C (n=30) - subgingival irrigation with 1 mL of saline; T (n=30) - subgingival irrigation with 1 mL of TTC-HCL (50 mg/mL). Ten animals in each group were euthanized at 7, 15 and 30 days posttreatment. The histometric values were statistically analyzed (

Students’ Perspectives on Use Behaviour of Learning Management Systems in Sri Lankan Universities

This research aims to explore the perceptions of students in using Learning Management System (LMS) in order to enhance the learning process of undergraduates in government universities in Sri Lanka.Many universities in Sri Lanka have implemented LMS to make their learning interactive and engaging.These institutions have made considerable amount of investments in terms of finance and other resources but the benefits enjoyed are far below expectations.Hence, it is of high recognition that a study is very much needed to understand the reason(s) for such low usage in Sri Lankan free education context. Quantitative study based on self-administered questionnaire survey was conducted.Out of the 15 government universities in Sri Lanka, 03 were selected. Results from 344 valid responses reveals that Attitude, Experience and Anxiety significantly influence the students’ use behaviour of LMS in Sri Lankan universities, while Efficacy and Collaboration do not have any impact. The research identifies what factors would influence these students’ use behaviour of LMS in state universities. Variables Students’ Attitude towards LMS, Efficacy, Experience, Anxiety and Collaboration with Lecturers and Students are considered to be the predictor variables and their influence and impact on Use Behaviour of LMS (predicted variable) is studied

Avaliação histológica e histométrica da terapia fotodinâmica no tratamento da doença periodontal experimental induzida em ratos diabéticos e não diabéticos

O objetivo do presente estudo foi avaliar histológica e histometricamente a influência da terapia fotodinâmica (PDT) no tratamento coadjuvante da doença periodontal (DP) experimental induzida em ratos diabéticos e não-diabéticos. Foram utilizados 180 ratos divididos em 2 grupos: Grupo A: 90 animais não-diabéticos e Grupo B: 90 animais diabéticos induzidos pela aloxana a 2% (42 mg/Kg). Nos Grupos A e B a DP foi induzida no primeiro molar inferior. Após 7 dias de evolução da DP, em todos animais de ambos os Grupos, a ligadura foi removida seguida de raspagem e alisamento radicular (RAR) e divididos conforme os tratamentos: I (RAR) - RAR e irrigação com 1 ml de soro fisiológico; II (TBO) - RAR e irrigação com 1 ml de azul de toluidina O (TBO 100 μg/ml); III (PDT) - RAR, irrigação com 1 ml de TBO e após 1 minuto irradiação com o laser em baixa intensidade. O laser (AsGaAl, 660 nm) foi aplicado na vestibular e lingual em 3 pontos eqüidistantes em cada região, com dose energética de 4 J/ponto. Dez animais de cada grupo experimental e tratamento foram sacrificados nos períodos de 7, 15 e 30 dias para a análise histológica e histométrica. Os dados histométricos foram submetidos à análise estatística (p<0,05). Os animais tratados com a PDT (Grupo A e B), apresentaram histologicamente tecido conjuntivo (TC) bem organizado e trabéculas ósseas presentes em toda a extensão da furca. Nos animais tratados com RAR nos dois grupos, o TC estava desorganizado, com intenso infiltrado inflamatório e áreas de reabsorções ósseas e cementárias. As alterações mais severas foram observadas no Grupo B. Histometricamente, no Grupo A, o tratamento com a PDT (0,33±0,05 mm2; 0,35±0,06 mm2; 0,27±0,07 mm2), promoveu menor perda óssea (p<0,05) na região de furca quando comparado com os animais tratados...The aim of this study was to evaluate histological and histometrically the influence of photodynamic therapy (PDT) as an adjuvant treatment on the experimentally induced periodontitis in diabetic and non-diabetic rats. One-hundred eighty rats were assigned to 2 groups: Group A: Ninety non-diabetic and Group B: Ninety alloxan-diabetic. In Group B, after 7 days of alloxan-diabetic induction (42 mg/Kg), the periodontal disease (PD) was induced at the first mandibular molar. Seven days after the establishment of PD, the ligatures were removed. Thereafter, all animals were submitted to scaling and root planing (SRP) and then divided according with the following protocols treatment: I (SRP) – SRP and irrigation with saline solution (1 mL); II (TBO) – SRP and irrigation with 1 mL of Toluidine Blue (TBO) (100 μg/mL); III (PDT) – SRP, irrigation with 1mL of TBO and after 1 minute, low-level laser therapy (LLLT). The LLLT GaAlAs (4 J) was performed in 3 equidistant points at the each buccal and lingual aspect of the first mandibular molar. Ten animals in each experimental group and treatment were sacrificed at 7, 15 and 30 days. Histologic and histometric analyses were performed. The histometric values were statistical analyzed ( p<0.05). The animals treated by PDT in Group A and B showed the furcation area fulfilled with a well-organized connective tissue (CT) and with bone trabeculae in all extension of furcation. In animals treated with SRP, the CT was poorly organized, showing an intense inflammatory infiltrate and areas with bone and cement resorption. The worst tissue response was found in Group B. Histometrically, in Group A, the animals treated by PDT (0.33±0.05 mm2; 0.35±0.06 mm2; 0.27±0.07 mm2) showed a lesser bone loss (p<0.05) in all experimental... (Complete abstract click electronic access below

Ação da terapia fotodinâmica no tratamento da doença periodontal induzida: estudo histológico em ratos

O presente estudo teve por objetivo avaliar histologicamente o efeito da terapia fotodinâmica (PDT) na progressão da doença periodontal induzida em ratos. Realizou-se a adaptação de uma ligadura de algodão na margem gengival do primeiro molar inferior esquerdo de cento e vinte ratos. Os animais foram divididos aleatoriamente em quatro grupos experimentais(n=30): Grupo I: nenhum tipo de tratamento realizado, somente a presença da ligadura; Grupo II (MB): tratamento com aplicação tópica de azul de metileno (100 æg/mL) dois dias após adaptação da ligadura; Grupo III (LLT): tratamento com Laser em baixa intensidade dois dias após adaptação da ligadura; e Grupo IV (PDT): tratamento com aplicação tópica de azul de metileno (100 æg/mL) seguido da aplicação do Laser em baixa intensidade dois dias após adaptação da ligadura. A superfície mesial dos dentes no Grupo III e IV foram irradiados com o Laser de diodo de GaAlAs, com 685 nm (50 mW, 120 s, 4.5 J/cm2). Todos os grupos foram subdivididos em subgrupos (n=10) e sacrificados nos períodos de 5, 15 e 30 dias pós-operatório. As peças foram processadas para análise histológica e coradas pela técnica de H&E. Através de um sistema de escores, vários parâmetros foram utilizados para avaliar o tecido conjuntivo, ligamento periodontal, superfície radicular e tecido ósseo. A análise estatística foi realizada pelo teste de Kruskal-Wallis, (p<0.05). Os resultados indicaram diferença no nível da inserção do ligamento periodontal entre o Grupo I (C) e Grupo III (LLT) (p=0,0327), Grupo II (MB) e Grupo III (LLT) (p=0,0118) e entre o Grupo III (LLT) e Grupo IV (PDT) (p=0,0076) no período de 15 dias de pó-operatório. Não ocorreu diferença estatisticamente significante...The purpose of this study was to histologically evaluate the effect of photodynamic therapy (PDT) on the progression of experimentally induced periodontal disease in rats. Cotton ligatures were placed at the gingival margin level of the lower left first molar in one hundred and twenty rats. The animals were then randomly divided evenly into 4 groups (n=30): Group I (C): no treatment; Group II (MB): treated with topical application of methylene blue (100æg/ml) 2 days after ligature placement; Group III (LLT): treated by low level laser therapy 2 days after ligature placement; and Group IV (PDT): treated with topical application of methylene blue (100æg/ml) followed by low level laser therapy 2 days after ligature placement. The mesial aspect of the teeth in Groups III and IV were irradiated using a 685nm GaAlAs laser (50mW, 120s, 4.5J/cm2). All groups were subdivided into subgroups (n=10) and euthanized at either 5, 15 or 30 days post-operative. Block sections were routinely processed for histological analysis using H&E stain. Using a scoring system, several biological parameters were used to evaluate the connective tissue, periodontal ligament, root surface and bone. The data were statistically analyzed (Kruskal-Wallis, p<0.05). The results showed significant differences in the periodontal attachment level between Group I (C) and Group III (LLT) (p=0,0327), Group II (MB) and Group III (LLT) (p=0,0118) and between Group III (LLT) and IV (PDT) (p=0.0076) at 15 days postoperative.There were no significant differences in any of the evaluated parameters...(Complete abstract click eletronic address below

Natural medicaments in endodontics: a comparative study of the anti-inflammatory action

The objective of this study was to evaluate the irritant potential of propolis, Casearia sylvestris, Otosporin and saline solution (control). Twenty-eight male Wistar rats were selected, anesthetized and four experimental sites were designed on their backs. Injections of 2% Evans blue were intravenously administered in the lateral caudal vein and 0.1 ml of the tested solutions was injected intradermally into the experimental sites. The animals were killed 1/2, 1, 3 and 6 hours after the injection of the solutions. Each piece of skin containing the lesion was immersed in formamide and incubated at 45ºC for 72 h. After filtration, optical density was measured in a spectrophotometer. Data were statistically analyzed by a 2-way non-parametric test. The highest values of extracted dye were observed at 3 hours characterizing a peak in the inflammatory process. Propolis was the least irritant solution. The natural medicaments tested in this study may be a valuable alternative for endodontic treatment

Influence of ovariectomy on healing of autogenous bone block grafts in the mandible: A histomorphometric study in an aged rat model

Purpose: The aim of this study was to evaluate quantitatively and qualitatively the influence of estrogen deficiency on autogenous bone block grafts in aged variectomized rats. Materials and Methods: Fifty 12-month-old female Wistar rats were used in the study. They were divided into 2 groups, an ovariectomized group and a sham-operated group. After 30 days the animals received autogenous block bone grafts on the angle of the mandible, harvested from the calvaria. The animals were euthanized at 7, 14, or 28 days postoperatively. Results: Histologic analysis showed that at 7 days postsurgery, the interface between graft and recipient site in the sham-operated group appeared filled by a granulation tissue with angiogenic activity, whereas the ovariectomized group still exhibited a blood clot and a granulation tissue in organization. on the 14th postoperative day, the interface in the shamoperated group was partially filled by newly formed bone establishing a union between the graft and the recipient site. The interface in the ovariectomized group was typically filled by granulation tissue with discrete osteogenic activity in most specimens. on the 28th postoperative day, the graft in the sham-operated group appeared histologically integrated to the mandible. However, the interface in the ovariectomized group appeared partially filled by newly formed bone, with areas of interposed connective tissue. The statistical analysis revealed that bone neoformation was significantly greater in the sham-operated group (57.41% at 14 days and 68.35 at 28 days) in comparison with the ovariectomized group (40.82% at 14 days and 53.09 at 28 days) at the 5% level. Conclusion: The estrogen depletion caused by the ovariectomy hindered the healing process of autogenous block bone grafts placed in the mandibles of aged rats

Vertical Limit Displacements of Masonry Structures

The safety level of masonry arches (and domes) is severely affected by displacements and/or rotations that may occur on its supports. When subjected to movements, the initial geometry of the masonry arch changes and hinges appear between voussoirs, following a ductile behavior and adapting to the new boundary conditions. Displacements may be either outwards or inwards, upwards or downwards, or even combined. This can result in an increase or decrease of the horizontal force. The structural safety of masonry arches (or vaults) decreases very much with displacements and/or rotations that may produce at the abutments. In some cases leading them to collapse if such movements are larger than certain thresholds, even if loads remain constant. This dissertation focuses on understanding how masonry arches are affected by vertical displacements on one of their supports, how their geometry changes and how their inner stresses evolve; in short, on how the stability and thus the safety level is affected. In particular, the effect of the geometry variation of an arch due to a change in the boundary conditions for different initial configurations. The study has focused on finding the line of thrust, a concept associated to the plasticity limit theorems, which allows to find a stable and safe configuration for each deformed geometry of the arch. To conclude, results are validated through lab tests in other institutions or specifically developed for this dissertation