Surface Free Energy, Interaction, and Adsorption of Calcium and Phosphate to Enamel Treated with Trimetaphosphate and Glycerophosphate.

This study aimed to evaluate the surface (γs) and interaction (ΔGiwi) free energy and calcium (Ca2+) and phosphate (PO43-) adsorption to dental enamel treated with sodium trimetaphosphate (TMP) or calcium glycerophosphate (CaGP) that had or had not been exposed to CaPO4-containing solutions. Bovine enamel blocks (n = 192; 24 blocks/group) were treated (2 mL/block; 2 min) with TMP (0%, 1%, 3%, and 9%) and CaGP (0, 0.25, 0.5, and 1%) or exposed to a CaPO4-containing solution. The adsorption of these compounds by enamel was assessed before and after treatment. γs and ΔGiwi and their apolar (γsLW and ΔGiwiLW) and polar (γsAB and ΔGiwiAB) components and acid-base interactions (γs+/γs-) were determined by the contact angles. The data were subjected to ANOVA, followed by the Student-Newman-Keuls test (p < 0.05). The adsorption of TMP was dose dependent (p < 0.001), and it reduced γs and γsAB and increased ΔGiwiAB (ΔGiwi > 0) and γs- when compared with the group without TMP (p < 0.001). The immersion in CaPO4-containing solution increased γs and γsAB and reduced ΔGiwiAB (ΔGiwi > 0) and γs- (p < 0.001). There was a correlation between the adsorption of TMP and Ca2+ (r = 0.916; p < 0.001) and PO43- (r = 0.899; p < 0.001). The adsorption of CaGP on the enamel was dose dependent (p < 0.001), reducing γs, ΔGiwiAB (ΔGiwi < 0), γsLW, and γs- when compared to the group without CaGP (p < 0.001). When exposed to the CaPO4-containing solution, there was an increase in ΔGiwiAB (ΔGiwi > 0), γsLW, and γs- and a decrease in γsAB (p < 0.001) without adsorption of Ca2+ by enamel. It may be concluded that TMP and CaGP were adsorbed onto the enamel, producing hydrophilic and hydrophobic surfaces, respectively. TMP produces electron donor sites that induce Ca2+ adsorption, while CaGP releases Ca2+ into the medium.

Evaluation of the relationship between obturation length and presence of apical periodontitis by CBCT: an observational cross-sectional study.

OBJECTIVE: The aim of this study was to evaluate the relationship between length of root canal obturation (RCO) and the presence of apical periodontitis (AP) in different dental groups using cone-beam computed tomography (CBCT) analysis. MATERIALS AND METHODS: A total of 392 roots with canal treatment performed for more than 4 years were evaluated using CBCT. Distances from the apex to the tip of filling material were measured and classified as more than 2 mm short of the apex, approximately 1-2 mm short of the apex, at the apex, and beyond the apex. Odds ratio, confidence interval, and the χ2 test were used for statistical analyses. RESULTS: The frequency of AP was significantly greater in molars than in the other tooth groups (p < 0.05). Moreover, RCO that ended 1-2 mm short of the apex was associated with a lower prevalence of AP in molars and premolars (p < 0.05) and in anterior teeth (p < 0.1) when compared with RCO at the apex, more than 2 mm short of the apex, or beyond the apex. When the RCO reached the apex, there was no difference in the presence of AP among dental groups (p > 0.05). CONCLUSION: The length of RCOs can influence the presence of AP, with molars showing a higher prevalence. RCOs ending 1-2 mm short of the apex are associated with an absence of AP. CLINICAL RELEVANCE: The length of obturation is related to the presence of apical peridontitis and consequently to the success of endodontic treatment.

Análise in vitro da energia livre de superfície no esmalte dentário tratado com glicerofosfato de cálcio e trimetafosfato de sódio, exposto ou não ao cálcio e fosfato / In vitro analysis of surface free energy in dental enamel treated with calcium glycerophosphate and sodium trimetaphosphate, whether exposed or not to the solution containing calcium and phosphate

Objetivo: Analisar in vitro a energia livre de superfície (Æ´s) no esmalte dentário após o tratamento com diferentes concentrações de Trimetafosfato de sódio (TMP) ou Glicerofosfato de cálcio (CaGP), exposto ou não a solução contendo cálcio (Ca) e fosfato (PO4), assim como determinar a adsorção de TMP, CaGP, Ca e PO4 ao esmalte dentário. Método: Blocos de esmalte bovino (n=192; 24 blocos/grupo) planificados e polidos foram tratados (2 mL/bloco/2 minutos) com TMP (0, 1, 3 e 9%) ou CaGP (0, 0,25, 0,5 e 1%), expostos ou não a solução contendo Ca/PO4. TMP, CaGP, Ca e PO4 foram analisados nas soluções antes e após o tratamento para calcular a adsorção ao esmalte. A Æ´s, os componentes apolar (Æ´s LW) e polar (Æ´s AB), e ácido/base (Æ´s +/Æ´s -) foram calculados pelo ângulo de contato de três líquidos sondas (água, diiodometano e etilenoglicol). Os dados foram submetidos à ANOVA seguido pelo teste Student-Newman-Keuls s (p<0,05). Resultados: A adsorção de TMP foi dose-dependente (p<0,001) e reduziu a Æ´s e Æ´s AB, e aumentou a Æ´s -, quando comparado ao grupo sem TMP (p<0,001). A solução contendo Ca/PO4 aumentou a Æ´s (p<0,050) e a Æ´s AB (p<0,001) e reduziu a Æ´s - (p<0,001). Houve correlação entre a adsorção de TMP e Ca (r = 0,916; p<0,001) e P (r = 0,899; p<0,001) ao esmalte. A adsorção de CaGP ao esmalte foi dose-dependente (p<0,001) diminuindo a Æ´s, Æ´s LW e Æ´s - quando comparado ao grupo sem CaGP (p<0,001). Quando exposto à solução de Ca/PO4, houve aumento da Æ´s LW e Æ´s -, e diminuição da Æ´s AB (p<0,001), sem adsorção de Ca ao esmalte. Conclusão: O TMP e CaGP foram adsorvidos ao esmalte reduzindo a Æ´s, devido a Æ´s AB ou Æ´s LW, respectivamente. O TMP produz sítios doadores de elétrons (Æ´s -) induzindo a adsorção de Ca enquanto o CaGP libera Ca para o meio(AU)

Objective: In vitro analysis of free surface enamel (Ƴs) in dental enamel after treatment with different concentrations of sodium trimetaphosphate (TMP) or calcium glycerophosphate (CaGP), exposed or not to the solution containing calcium (Ca) and phosphate (PO4), as well as to determine the adsorption of TMP, CaGP, Ca and PO4 to the dental enamel. Design: Bovine enamel blocks (n = 192; 24 blocks/group) planned were treated (2 mL/block; 2 minutes) with TMP (0, 1, 3 e 9%), CaGP (0, 0.25, 0.5 e 1%) exposed or not to the solution containing CaPO4 were analyzed in the solutions before and after the treatment will be determined for the calculation of the adsorption of these to the enamel. The Ƴs and their components Ƴs LW Lifshitz-van der Waals surface tension component , Ƴs AB and Lewis acid-base interaction (Ƴs +/Ƴs -) was calculated by measuring the contact angles of three liquids probes (deionized water, diiodomethane and ethylene glycol). The data were submited to ANOVA followed by Student-Newman Keuls test (p<0.05). Results: The adsorption of TMP was dose-dependent (p<0.001) reduced the Ƴs and Ƴs AB when compared to the group without TMP (p<0.001). The solution containing Ca/PO4 increased the Ƴs, Ƴs AB and reduced the Ƴs - (p<0.001). There was a correlation between adsorption of TMP and Ca (r = 0.916; p<0.001) and P (r = 0.899; p<0.001) to the enamel. The adsorption of CaGP to the enamel was dose-dependent (p<0.001) reducing the Ƴs, Ƴs LW and Ƴs - when compared to the group without CaGP (p<0.001). When exposed the de Ca/PO4 solution there was an increase of Ƴs LW and Ƴs - , reduction of Ƴs AB (p<0.001), without adsorption of calcium to the enamel. Conclusion: The TMP was adsorbed to the enamel reducing the Ƴs due the Ƴs LW or Ƴs LW, respectively. The TMP generates electrondonor inducing adsorption of Ca while CaGP releases Ca to the medium(AU)