Ogliari Fabrício Aulo, da Silva Eduardo de Oliveira, Lima Giana da Silveira, Madruga Francine Cardozo, Henn Sandrina, Bueno Márcia, Ceschi Marco Antônio, Petzhold Cesar Liberato, Piva Evandro
Operative Dentistry Department, School of Dentistry, Federal University of Pelotas, RS, Brazil.
J Dent. 2008 Mar;36(3):171-7. doi: 10.1016/j.jdent.2007.11.003.
The aim of this study was to synthesize an acidic monomer using an alternative synthetic pathway and to evaluate the influence of the acidic monomer concentration on the microtensile bond strength to dentin.
The intermediary 5-hydroxypentyl methacrylate (HPMA) was synthesized through methacrylic acid esterification with 1,5-pentanediol, catalyzed by p-toluenesulfonic acid. To displace the reaction balance, the water generated by esterification was removed by three different methods: anhydrous sodium sulfate; molecular sieves or azeotropic distillation. In the next step, a phosphorus pentoxide (4.82 mmol) slurry was formed in cold acetone and 29 mmol of HPMA was slowly added by funnel addition. After the reaction ended, solvent was evaporated and the product was characterized by 1HNMR and FTIR. The phosphate monomer was introduced in a self-etch primer at concentrations of 0, 15, 30, 50, 70 and 100 wt%. Clearfil SE Bond was used as commercial reference. Microtensile bond strength to dentin was evaluated 24h after the bonding procedures, followed by fracture analysis (n=20). Data was submitted to ANOVA and Tukey's post hoc test.
The highest yield was obtained (62%) when azeotropic distillation was used, while the reaction with molecular sieves was not feasible. The phosphoric moiety attachment to the monomer was successfully performed with a quantitative yield that reached around 100%. The acidic monomer concentration significantly affected the bond strength and the highest mean (55.1+/-12.8 MPa) was obtained when 50% of acidic monomer was used.
The synthesis pathways described in the present study appear to be a viable alternative for developing phosphate monomers.
本研究的目的是使用一种替代合成途径合成一种酸性单体，并评估酸性单体浓度对与牙本质的微拉伸粘结强度的影响。
通过对甲苯磺酸催化甲基丙烯酸与1,5 - 戊二醇进行酯化反应合成中间体甲基丙烯酸5 - 羟基戊酯（HPMA）。为了使反应平衡发生移动，通过三种不同方法除去酯化反应生成的水：无水硫酸钠；分子筛或共沸蒸馏。在下一步中，在冷丙酮中形成五氧化二磷（4.82 mmol）浆液，并通过漏斗缓慢加入29 mmol的HPMA。反应结束后，蒸发溶剂，产物通过1HNMR和FTIR进行表征。将磷酸盐单体以0、15、30、50、70和100 wt%的浓度引入自酸蚀底漆中。Clearfil SE Bond用作商业对照。在粘结程序24小时后评估与牙本质的微拉伸粘结强度，随后进行断裂分析（n = 20）。数据提交给方差分析和Tukey事后检验。
使用共沸蒸馏时获得了最高产率（62%），而与分子筛的反应不可行。磷酸部分成功地连接到单体上，定量产率达到约100%。酸性单体浓度显著影响粘结强度，当使用50%的酸性单体时获得了最高平均值（55.1±12.8 MPa）。
本研究中描述的合成途径似乎是开发磷酸盐单体的一种可行替代方法。
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