改性4.0代聚酰胺-胺对敏感牙本质小管矿化的封闭作用

Effect of generation modified 4.0 polyamidoamine dendrimer on the mineralization of demineralized dentinal tubules in vitro

目的体外对比观察4. 0代聚酰胺-胺改性前后在不同时点对敏感牙本质小管的生物矿化作用。方法收集完整的离体第三磨牙39颗,切取釉牙骨质界处约2 mm厚牙本质片在体外建立敏感牙本质模型,随机分成三组。未改性PAMAM组使用未改性4. 0代PAMAM(聚酰胺-胺)处理;高露洁组用高露洁抗过敏牙膏处理;改性PAMAM组使用改性4. 0代PAMAM处理,之后三组样本同时浸泡于人工唾液,于第2,4,6,8周分别各随机抽取两个样本,拍摄横断面照片(×5 000),观察在不同时点下表面牙本质小管口的封闭情况,以获得牙本质表面矿化的定性效果。8周结束后,将剩余的31组样本分别进行显微硬度测试,以获得各组敏感牙本质表面矿物质沉积情况的定量结果。结果在5 000倍SEM下,三组样本在第8周牙本质小管口均基本已被完全封闭,几乎没有暴露的牙本质小管,高露洁组和改性后PAMAM组晶体沉积效果更好,均匀细密。第8周高露洁组、改性PAMAM组的显微硬度值明显要高于未改性PAMAM组(P <0. 05),高露洁组和改性PAMAM组的显微硬度值差异无统计学意义。结论改性后4. 0代聚酰胺-胺可显著提高敏感牙本质小管的生物矿化及封闭作用,提示其治疗牙本质敏感的潜在价值。

Objective To in vitro observe the effect of modified 4. 0 th generation of polyamidoamine dendrimer( PAMAM) on the biological mineralization of demineralized dentine tubules at different time points. Methods Thirty-nine extracted third molar were collected to obtain 2 mm-thick dentine slices from the cemento-enamel junction for establishing sensitive dention model in vitro. Samples were randomly divided into 3 groups. Slices were treated with unmodified generation 4. 0 polyamidoamine dendrimer in control group A,colgate of allergy toothpaste in control group B,and modified generation 4. 0 polyamidoamine dendrimer in experimental group. After immersion in artificial saliva for 2,4,6,and 8 weeks,the mineralization condition of dentine slices was observed using the scanning electron microscope( SEM). In addition,the difference of micro-hardness between the three groups was also compared at the end of 8 weeks. Results Electron microscopy results showed that dentinal tubules were almost closed in three groups at 8 week,but the crystal deposition effect in control group B and experiment group were significantly better than that of control group A. The microhardness values in control group B and experiment group was significantly higher than that of control group A( P < 0. 05),but there was no significant difference between control group B and experimental group. Conclusion The modified 4. 0 th PAMAM could promote the biological mineralization and the deposition of inorganic minerals,and it is promising in treatment of dentin hypersensitivity.