Hydroxyl and calcium ions diffusion from endodontic materials through roots of primary teeth - in vitro study

Abstract

) and hydroxyl (OH -) ions from materials with a calcium hydroxide base -Ca(OH) 2 through the intact roots of deciduous teeth. This diffusion of ions is important for periapical healing. Forty-six deciduous teeth were selected and instrumented to their working length with #40 files. The teeth were washed during cleaning and shaping with a 1% sodium hypochlorite (NaOCl) solution. The canals were dried with paper points. The teeth were divided into 4 groups based on the sealer type, with 10 specimens in each group. A fifth group of 6 teeth without sealer constituted the control group. The materials used as sealers were: Ca(OH) 2 paste associated to propylene glycol (CaPE) thickened at the proportion of 2:1 w/v; UFSC (Federal University of Santa Catarina) paste -a mixture of 0.3g of zinc oxide with 0.3g of Ca(OH) 2 with 0.2ml of olive oil 1:1 w/w; Vitapex ® and Sealapex ® . The coronal access was sealed with a glass ionomer after the root had been filled with each sealer. A one-third apical surface and foramen was hardpressed with Araldite ® . The teeth were stored individually in flasks containing saline solution at 37 o C and 100% humidity. The OH -and Ca +2ions diffusion levels were determined using a pH meter and an atomic absorption spectrometer. Data were collected at 48 hours and at intervals of 7, 30, 45 and 60 days. Statistical analysis was performed using ANOVA to compare groups. In the pH evaluation, the CaPE group presented the largest OH-ions diffusion, which peaked at sixty days (p=0.0309), when compared to the other groups (p<0.0001). In relation to amount of Ca +2 ions released, the CaPE paste showed the best results, followed by the UFSC's paste. These results suggest that the CaPE paste was the material that allowed the highest diffusion of OH -and Ca +2 ions. Uniterms: Calcium hydroxide; Atomic absorption spectrophotometer; Ion exchange; Root canal filling materials; Primary teeth. objetivo desta pesquisa foi avaliar a difusão de íons Ca +2 e OH -de materiais endodônticos a base hidróxido de cálcio -Ca(OH) 2 , através da raiz intacta de dentes decíduos. 46 dentes decíduos foram selecionados e instrumentados em seu comprimento de trabalho até a lima # 40, e irrigados durante o preparo com solução de hipoclorito de sódio 1%, e secos com cones de papel absorvente. Os dentes foram separados em 4 grupos de 10 dentes cada conforme o material obturador, e um grupo controle com 6 dentes permaneceu vazio. Os materiais utilizados como obturadores foram: pasta de Ca(OH) 2 associada ao propilenoglicol espessada (CaPE) na proporção de 0,4g de pó para 0,2ml de líquido; pasta UFSC, mistura de 0,3g de pó de óxido de zinco com 0,3g de pó de Ca(OH) 2 associado a 0,2ml de óleo de oliva; Vitapex® e Sealapex®. Após a obturação, todos os dentes tiveram o forame e terço apical selado com Araldite® e o acesso coronal selado com ionômero de vidro, permanecendo em frascos individuais com a raiz submersa em solução fisiológica, em estufa a 37

Application of 17% EDTA Enhances Diffusion of ⁴⁵Ca-labeled OH^&minus; and Ca²⁺ in Primary Tooth Root Canal

“…The cervical and apical portions of the specimens were sealed, so the only means of passage were the dentinal tubules and cementum, proving that OH − and Ca 2+ were released through the root, which is similar to findings reported in previous studies with primary 3,14) and permanent teeth 20,24) . To assess diffusion of OH − and Ca 2+ , the roots were immersed in saline solution (pH=6.00).…”

“…This is in agreement with findings reported by other authors, who, despite observing peak diffusion at 7 days, found a high degree of diffusion on the first day of analysis 3,18) . However, in disagreement with these results, Nunes and Rocha 14) , using an atomic absorption spectrophotometer unit, found greater diffusion of Ca 2+ after 7 days, with maximal values reached at day 30. This disparity may be related to differences in the methodologies employed in these studies.…”

“…The length of immersion was established in reference to clinical reports on periradicular lesions 17,24) . Unlike in other studies 14,21) , however, here the saline solution into which the root was immersed was replaced after each evaluation to allow maximal diffusion of ions without saturation of the medium 8) .…”

“…This can be seen in the higher rates of Ca 2+ release. The time needed for calcium hydroxide to optimally disinfect the root canal is still unknown and might be related to the type of microorganism involved, location of the microorganism in the root canal system, presence or absence of smear layer, and presence or absence of root canal exudation 14,15) . Despite not achieving statistical significance in the intra-group analysis, peak release of Ca 2+ occurred on day 3 in GIII.…”

“…Cleaning and disinfection of the root canal are key to the success of a pulpectomy. The proper combination of dental instruments, irrigation with effective solutions, temporary dressing, and correct filling of the root canal increase the odds of success 14) . The chelating agent ethylenediaminetetraacetic acid (EDTA) can be used to remove the smear layer formed during the chemicalmechanical preparation of the canal 15,19) .…”