Soares C J, Ferreira M S, Bicalho A A, de Paula Rodrigues M, Braga Ssl, Versluis A
Oper Dent. 2018 Jan/Feb;43(1):71-80. doi: 10.2341/16-325-L. Epub 2017 Oct 4.
To analyze the effect of pulp-capping materials and resin composite light activation on strain and temperature development in the pulp and on the interfacial integrity at the pulpal floor/pulp-capping materials in large molar class II cavities.
Forty extracted molars received large mesio-occlusal-distal (MOD) cavity bur preparation with 1.0 mm of dentin remaining at the pulp floor. Four pulp-capping materials (self-etching adhesive system, Clearfil SE Bond [CLE], Kuraray), two light-curing calcium hydroxide cements (BioCal [BIO], Biodinâmica, and Ultra-Blend Plus [ULT], Ultradent), and a resin-modified glass ionomer cement- (Vitrebond [VIT], 3M ESPE) were applied on the pulpal floor. The cavities were incrementally restored with resin composite (Filtek Z350 XT, 3M ESPE). Thermocouple (n=10) and strain gauge (n=10) were placed inside the pulp chamber in contact with the top of the pulpal floor to detect temperature changes and dentin strain during light curing of the pulp-capping materials and during resin composite restoration. Exotherm was calculated by subtracting postcure from polymerization temperature (n=10). Interface integrity at the pulpal floor was investigated using micro-CT (SkyScan 1272, Bruker). The degree of cure of capping materials was calculated using the Fourier transform infrared and attenuated total reflectance cell. Data were analyzed using one-way analysis of variance followed by the Tukey test (α=0.05).
Pulpal dentin strains (μs) during light curing of CLE were higher than for other pulp-capping materials ( p<0.001). During resin composite light activation, the pulpal dentin strain increased for ULT, VIT, and CLE and decreased for BIO. The pulpal dentin strain was significantly higher during pulp-capping light activation. The temperature inside the pulp chamber increased approximately 3.5°C after light curing the pulp-capping materials and approximately 2.1°C after final restoration. Pulp-capping material type had no influence temperature increase. The micro-CT showed perfect interfacial integrity after restoration for CLE and ULT; however, gaps were found between BIO and pulpal floor in all specimens. BIO had a significantly lower degree of conversion than ULT, VIT, and CLE.
Light curing of pulp-capping materials caused deformation of pulpal dentin and increased pulpal temperature in large MOD cavities. Shrinkage of the resin composite restoration caused debonding of BIO from the pulpal floor.
分析盖髓材料和树脂复合材料光固化对大磨牙Ⅱ类洞牙髓内应变和温度变化的影响，以及对髓室底/盖髓材料界面完整性的影响。
选取40颗离体磨牙，制备近中-咬合-远中（MOD）大窝洞，髓室底保留1.0 mm厚的牙本质。在髓室底分别应用四种盖髓材料（自酸蚀粘结系统，Clearfil SE Bond [CLE]，可乐丽公司）、两种光固化氢氧化钙水门汀（BioCal [BIO]，Biodinâmica公司，和Ultra-Blend Plus [ULT]，Ultradent公司）以及一种树脂改性玻璃离子水门汀（Vitrebond [VIT]，3M ESPE公司）。窝洞用树脂复合材料（Filtek Z350 XT，3M ESPE公司）逐层修复。在髓室内与髓室底顶部接触处放置热电偶（n = 10）和应变片（n = 10），以检测盖髓材料光固化过程中和树脂复合材料修复过程中的温度变化和牙本质应变。通过聚合温度减去后固化温度计算放热值（n = 10）。使用微型CT（SkyScan 1272，布鲁克公司）研究髓室底的界面完整性。使用傅里叶变换红外光谱和衰减全反射池计算盖髓材料的固化程度。数据采用单因素方差分析，然后进行Tukey检验（α = 0.05）。
CLE光固化过程中牙髓牙本质应变（μs）高于其他盖髓材料（p < 0.001）。在树脂复合材料光固化过程中，ULT、VIT和CLE的牙髓牙本质应变增加，BIO的牙髓牙本质应变降低。盖髓材料光固化过程中牙髓牙本质应变显著更高。盖髓材料光固化后髓室内温度升高约3.5°C，最终修复后升高约2.1°C。盖髓材料类型对温度升高无影响。微型CT显示CLE和ULT修复后界面完整性良好；然而，所有标本中BIO与髓室底之间均发现间隙。BIO的转化率显著低于ULT、VIT和CLE。
盖髓材料光固化导致大MOD窝洞牙髓牙本质变形并使牙髓温度升高。树脂复合材料修复体的收缩导致BIO与髓室底脱粘。
