Effects of angiotensin II type I receptor blocker losartan on orthodontic tooth movement.

INTRODUCTION: Drugs that block the renin-angiotensin system (RAS) are widely used for treating hypertension, heart and kidney failure, and the harmful effects of diabetes. Components of the RAS have been identified in various organs, but little is known of their effects on bone remodeling. The aim of this study was to evaluate whether the blockage of the RAS influences strain-induced bone remodeling in a model of orthodontic tooth movement. METHODS: An orthodontic appliance was placed in C57BL6/J mice that were randomly divided into 2 groups: vehicle-treated mice (VH) and mice treated with losartan (an angiotensin II receptor blocker). Orthodontic tooth movement and the number of tartrate-resistant acid phosphatase-positive cells were determined by histopathologic analysis. The expression of mediators involved in bone remodeling was evaluated by quantitative real-time polymerase chain reaction. Blood pressure was measured before and during the experimental period. RESULTS: Orthodontic tooth movement and tartrate-resistant acid phosphatase-positive cells were significantly reduced in the losartan group compared with the VH group. mRNA levels of osteoclast markers (RANK, RANKL, cathepsin K, and metalloproteinase 13) were lower in the losartan mice than in the VH group, whereas the expressions of osteoblast markers and negative regulators of bone resorption (periostin, dentin matrix protein, alkaline phosphatase, collagen 1A1, semaphorin 3A3, metalloproteinase 2, and osteoprotegerin) were higher in the VH group. CONCLUSIONS: Blockage of the RAS system decreases osteoclast differentiation and activity and, consequently, results in decreased strain-induced bone remodeling in orthodontic tooth movement.

Effect of Lithothamnium sp and calcium supplements in strain- and infection-induced bone resorption.

OBJECTIVE: To investigate the effect of Lithothamnium sp (LTT) supplement, a calcium-rich alga widely used for mineral reposition, on strain-induced (orthodontic tooth movement [OTM]) and infection-induced bone resorption (periodontal disease [PD]) in mice. MATERIALS AND METHODS: Mice were divided into two bone resorption models: one with an orthodontic appliance and the other with PD induced by the oral inoculation of Aggregatibacter actinomycetencomitans (Aa). Both groups were fed a regular diet (vehicle), LTT-rich diet (LTT), or calcium-rich diet (CaCO3). Alveolar bone resorption (ABR), the number of osteoclasts, and the levels of tumor necrosis factor α (TNF-α), calcium, and vitamin D3 were evaluated. RESULTS: The number of osteoclasts was reduced in LTT and CaCO3 mice, which led to diminished OTM and infection-induced alveolar bone loss. In addition, LTT- and calcium-treated groups also presented decreased levels of TNF-α in periodontal tissues and increased levels of calcium in serum. CONCLUSIONS: These results indicate that the LTT supplement influences ABR, probably due to its calcium content, by affecting osteoclast function and local inflammatory response, thus modulating OTM and PD.

Experimental model of tooth movement in mice: a standardized protocol for studying bone remodeling under compression and tensile strains.

During orthodontic tooth movement (OTM), alveolar bone is resorbed by osteoclasts in compression sites (CS) and is deposited by osteoblasts in tension sites (TS). The aim of this study was to develop a standardized OTM protocol in mice and to investigate the expression of bone resorption and deposition markers in CS and TS. An orthodontic appliance was placed in C57BL6/J mice. To define the ideal orthodontic force, the molars of the mice were subjected to forces of 0.1N, 0.25 N, 0.35 N and 0.5 N. The expression of mediators that are involved in bone remodeling at CS and TS was analyzed using a Real-Time PCR. The data revealed that a force of 0.35 N promoted optimal OTM and osteoclast recruitment without root resorption. The levels of TNF-α, RANKL, MMP13 and OPG were all altered in CS and TS. Whereas TNF-α and Cathepsin K exhibited elevated levels in CS, RUNX2 and OCN levels were higher in TS. Our results suggest that 0.35 N is the ideal force for OTM in mice and has no side effects. Moreover, the expression of bone remodeling markers differed between the compression and the tension areas, potentially explaining the distinct cellular migration and differentiation patterns in each of these sites.

Influência da deficiência de estrógeno na movimentação ortodôntica / The influence of estrogen deficiency in orthodontic tooth movement

O perfil dos pacientes que procuram tratamento ortodôntico mudou nas últimas décadas. O número de pacientes adultos e idosos do sexo feminino cresceu consideravelmente. Esta mudança na demanda trouxe desafios biológicos para o atendimento ortodôntico, por muitas vezes tratarem-se de pacientes com alterações sistêmicas ou sob uso de medicamentos controlados. Dentre estes, podese citar a deficiência de estrógeno e a osteoporose, comuns nessa faixa etária, e que podem interferir na movimentação dentária ortodôntica (MDO). Esta revisão de literatura se propõe a descrever os aspectos biológicos da movimentação ortodôntica e a identificar como a deficiência de estrógeno e a osteoporose podem interferir na remodelação óssea e, consequentemente, na MDO. Este artigo objetiva ainda alertar o ortodontista da importância de se avaliar cuidadosamente a condição sistêmica dos pacientes com possível deficiência de estrógeno/osteoporose, para um correto diagnóstico e elaboração do plano de tratamento.

An increasing number of adult patients are seeking for orthodontic treatment in the last decades, especially postmenopausal women. This represents a biological challenge for the orthodontic treatment, since these patients more often present systemic disorders or are routinely using controlling medication. Among them, estrogen deficiency and osteoporosis are commonly reported in elderly women. This review article elucidates the biological aspects of orthodontic tooth movement, emphasizing how the estrogen deficiency may interfere with this process. This literature review suggests that estrogen deficiency and the use of drugs for osteoporosis treatment may alter the bone remodeling and, consequently, the orthodontic tooth movement. The orthodontist must be aware of the patient’s systemic condition to better elaborate the correct treatment plan.

Distribuição de cirurgiões dentistas pelo território do Estado da Bahia 2007 / Distribution Of Dentists Within The State Of Bahias Jurisdiction 2007

Este estudo transversal verificou a distribuição dos cirurgiões-dentistas (CD) no estado da Bahia, a razão de habitantes barra CD nos municípios e a relação entre essa razão, renda per capita e Índice de Desenvolvimento Humano Municipal (IDH-M). A analise foi realizada confrontando duas bases diferentes de dados: Conselho Federal de Odontologia (CFO) e Cadastro Nacional de Estabelecimentos de Saúde (CNES). Foi utilizada a população residente do Instituto Brasileiro de Geografia e Estatística (IBGE) para 2007. Foi realizada analise descritiva dos dados e verificou-se a associação entre as variáveis através do teste ?Ô2. As informações do CFO e do CNES foram divergentes. De acordo com o CFO, em 164 municípios (39,5%), não existiam dentistas; para o CNES, apenas 16 municípios (3,8%) encontravam-se nesta situação. Verificou-se uma associação positiva (p<0,05) entre a renda per capita e a razão habitantes/CD. Os resultados apontam para a necessidade de uma distribuição mais uniforme dos CD pelo território baiano, garantindo acesso aos serviços de saúde bucal para toda a população. A analise da distribuição de serviços odontológicos através desta metodologia da uma noção da localização geográfica dos profissionais nas diferentes subdivisões territoriais e dos fatores que interferem na sua fixação, contudo e bastante limitada. Para orientar a (re) estruturação de sistemas/serviços de saúde são necessários estudos que dêem conta de questões como cobertura, acessibilidade, implantação e qualidade dos serviços.

The current research aims at verifying the presence of dentists within the State of Bahia's, Brazil, jurisdiction and its relation to the population, per capita income and each town apostrofo s Index of Human Development. For this purpose, two data bases were used one from theDentistry Federal Council and the other from the National Health Establishment?s Records - toobtain the amount of dentists acting in the public sector and check the accuracy of informationin the Council?s records. According to Dentistry Federal Council, 164 municipalities 39.5% hadno dentists, whereas the National Health Establishment?s Records identifies only 16 counties3,8% in this situation. Through the obtained results it is possible to observe that the proportionof habitants dentists becomes more favorable according to the per capita income increase ofthe city p 0.05. It is also emphasized the need for the Council?s more accurate verificationof professionals actuation in the countryside. Although still limited, this methodology enhancesverifying the presence of dentists within the state territory, and points out that future studies mustassess coverage, accessibility, implementation and quality of health services.