Loss Of Dental Structure Research Articles

The Influence of Cavity Design and Glass Fiber Posts on Biomechanical Behavior of Endodontically Treated Premolars

The aim of this study was to evaluate the effect of cavity design and glass fiber posts on stress distributions and fracture resistance of endodontically treated premolars. Fifty extracted intact mandibular premolars were divided into 5 groups ( n = 10): ST, sound teeth (control); MOD, mesio-occlusal-distal preparation + endodontic treatment (ET) + composite resin restoration (CR); MODP, mesio-occlusal-distal + ET + glass fiber post + CR; MOD2/3, mesio-occlusal-distal + two thirds occlusal-cervical cusp loss + ET + CR; and MODP2/3, mesio-occlusal-distal + two thirds cusp loss + ET + glass fiber post + CR. The specimens were loaded on a cusp slope until fracture. Fracture patterns were classified according to four failure types. Stress distributions were evaluated for each group in a two-dimensional finite element analysis. The fracture resistance of the MODP, MOD2/3, and MODP2/3 groups was significantly lower than the ST and MOD groups (p < 0.05). The loss of dental structure and the presence of fiber post restoration reduced fracture resistance and created higher stress concentrations in the tooth-restoration complex. However, when there was a large loss of dental structure (MODP2/3), the post reduced the incidence of catastrophic fracture types.

In vitro evaluation of the effect of natural orange juices on dentin morphology

The patient's diet has been considered an important etiological factor of dentin hypersensitivity. The frequent ingestion of acidic substances can promote the loss of dental structure or remove the smear layer. The purpose of this study was to evaluate the degree of smear layer removal and dentinal tubules exposure by different natural orange juices. Extracted human teeth were submitted to manual scaling in order to develop the smear layer. Seventy dentin samples were obtained and distributed into the following groups: Control, lime orange, lime, valência orange, navel orange, mandarin, and tangerine. Each group included 2 methods of application: Topical and topical + friction. After preparation for SEM analysis, photomicrographs were assessed by a blind calibrated examiner using an index system. The Kruskal-Wallis test indicated a significant influence of the orange juices on smear layer removal. Significant difference was observed between navel orange, valência orange, mandarin and the control group (p < 0.05). These orange juices resulted in greater removal of the smear layer and greater opening of dentinal tubules. The comparison between the application methods for each group using the Mann-Whitney test showed that friction increased smear layer removal significantly only for lime orange and lime. The data suggest that certain natural orange juices are more effective in terms of smear layer removal and dentinal tubules exposure than others.

Tetralogia de Fallot e sua repercussão na saúde bucal

OBJETIVO: Relatar o caso de um paciente com tetralogia de Fallot e sua condição bucal. DESCRIÇÃO DO CASO: Paciente do gênero masculino atendido no Curso de Especialização em Odontopediatria da Escola de Aperfeiçoamento Profissional da Associação Brasileira de Odontologia da seção Paraná dos cinco aos sete anos de idade. O exame clínico intrabucal inicial revelou quadro de cárie severa da infância. Durante o acompanhamento, verificou-se a erupção dos primeiros molares permanentes com a presença de defeitos de desenvolvimento de esmalte e perda de estrutura dental. À anamnese, a mãe relatou que o paciente foi portador de tetralogia de Fallot e que a cirurgia corretora foi realizada com um ano e 11 meses de idade. COMENTÁRIOS: A formação do esmalte dental dos primeiros molares permanentes ocorre a partir do primeiro mês de vida e é finalizada entre dois e quatro anos de idade. Neste caso, tal etapa coincidiu com o período anterior à cirurgia para correção da tetralogia de Fallot, fato que pode ter interferido negativamente no processo de mineralização dos primeiros molares permanentes. Os defeitos de desenvolvimento do esmalte podem levar a perda de estrutura dental, favorecendo o aparecimento da cárie dentária. Dessa forma, o odontopediatra deve realizar um diagnóstico precoce dessas alterações e intervir preventivamente para evitar a perda de tais dentes. Uma anamnese bem detalhada e a maior interação entre pediatras e odontopediatras podem proporcionar melhor acompanhamento de crianças com fatores de risco para apresentar defeitos de desenvolvimento do esmalte dentário.

Effect of an iron mouthrinse on enamel and dentine erosion subjected or not to abrasion: An in situ/ ex vivo study

Objectives This in situ/ ex vivo study evaluated whether a rinse with an iron solution could reduce wear and the percentage of microhardness change of human enamel and dentine submitted to erosion followed by brushing after 1 or 30 min. Design During 2 experimental 5-day crossover phases (wash-out period of 10 days), 10 volunteers wore intraoral palatal devices, with 12 specimens (6 of enamel and 6 of dentine) arranged in 3 horizontal rows (4 specimens each). In one phase, the volunteers immersed the device for 5 min in 150 mL of cola drink, 4 times a day. Immediately after immersion, no treatment was performed in one row. The other row was brushed after 1 min using a fluoride dentifrice and the device was replaced into mouth. After 30 min, the remaining row was brushed. In the other phase, the procedures were repeated, but after immersion the volunteers rinsed for 1 min with 10 mL of a 10 mM ferrous sulphate solution. Changes in surface microhardness (%SMH) and wear (profilometry) of enamel and dentine were measured. Data were tested using ANOVA and Tukey's tests ( p < 0.05). Results The enamel presented more wear than dentine, under all experimental conditions. The iron solution caused a significant reduction on the %SMH in enamel, and a significant reduction on the wear in dentine, regardless the other conditions. Conclusions Rinsing with an iron solution after an erosive attack, followed or not by an abrasive episode, may be a viable alternative to reduce the loss of dental structure.