Effect of CO2 Laser Irradiation and Direct Pulp Capping using Experimentally Developed High Molecular Pulp Capping Agents: the Wound Healing Mechanisms of Exposed Pulp.

将羟基磷酸钙（HAP）、磷酸二钙脱水（刷石：DCPD）、磷酸三钙β (whitrokite: β-TCP)和磷酸八钙（OCT）四种磷酸钙作为牙本质修复促进剂，与实验单体液体混合，制备直接盖髓剂和牙基质粘结剂。聚合后的磷酸钙通过扫描电镜（SEM）、电子能谱（EPMA）和ICP原子发射光谱（ICP）对其分散、形状和组成进行了分析。结果表明：1)磷酸钙粉体在聚合单体液中像分散填料一样分散在复合树脂中。在物料混合制备过程中，振动和磨粒对粉体的分散有很大影响。2) Ca与p的浓度相对较高，而Mg仅以微量存在，且仅在线分析时检测到。3)每种磷酸钙对Ca和p的洗脱量不同，洗脱量受每种磷酸钙溶解度积（Ksp）的影响。4)应用该材料作为直接盖髓剂，尤其能促进牙本质的修复性形成，提高创面愈合的可靠性，尤其能改善盖髓后第一阶段的创面愈合。5)在暴露牙髓附近发现聚合牙髓封盖剂和粘结剂中的磷酸钙。在直接接触促进钙化作用、从磷酸钙中洗脱出钙和磷的离子作用以及ph变化影响暴露牙髓表面环境变化的条件下，可有效促进修复性牙本质的形成。在一定磷酸钙用量下，共制备了12种粘结剂。用实验引物和12种粘结剂对大鼠暴露的牙髓直接封盖。直接盖髓后，分别于实验1、3、7、14、28天处死。在光学显微镜下进行免疫组织化学和组织病理学检查炎症和修复性牙髓改变。结果如下：1)第1天各组均出现轻度炎症变化，但随着时间的推移炎症变化逐渐减弱（3,7 d）。2)未使用磷酸钙的组在第14天几乎没有牙本质修复形成，但在第28天有少量牙本质修复形成。3)使用磷酸钙的组在第14天就已经发现了牙本质修复形成，并且随着时间的推移逐渐增多，直至第28.d。4)磷酸钙的种类和浓度对牙本质修复形成有明显影响。此外，引物之间也存在差异。5)在含磷酸钙组中，MB5组（β-TCP 5wt%）、MB9组（HAP 5wt%、β-TCP 5wt%）、MB1组（HAP 5wt%）、MB2组（HAP 1wt %）和MB3组（β-TCP 5wt%）修复性牙本质形成相对较多。总的来说，含有β-TCP的组修复性牙本质形成更早。6)在实验开发的引物中，MP3（含5-NMSA 2wt%的MB引物）比含有抗菌单体MDPB的引物（ABP）表现出更小的炎症变化。MB1与MP3联合使用，正畸牙本质的炎症变化最小，修复程度最高。结果表明，MB1与MP3联合应用对直接封盖后一期创面愈合最可靠。在CO_2激光照射组中，Opelaser^<【〇】R】>0 03 S II SP（吉田牙科制造公司）。炭化后直接用mb覆盖牙髓表面，结果如下：1)第1天炎症变化稍强。但随着时间的推移，它们消失了。2)即使在第14.3 d后也未见修复性牙本质形成。3)即使在第28 d后也几乎未见修复性牙本质形成。相反，在牙髓壁上观察到大量刺激性牙本质的形成。4)在牙髓炭化层下可见不规则型牙本质基质形成。5)牙本质壁辐照区可见碳化层、苏木精染色良好的坏死层和伊红染色良好的蛋白质变性层。6)激光照射引起的碳化和坏死层阻碍了牙本质的形成，延迟了牙髓的创面愈合。这两层都不能作为隔绝外界刺激的层，也不能作为牙髓的保护层。7)辐照条件分为轻度、中度（有LLLT效应）和强水平。用CO_2激光对四种含磷酸钙的直接盖髓剂和粘结剂（MB8、MB9、MB11和MB12）和引物（MP）进行了实验研究。两组间无明显差异，证实轻度照射能使牙髓愈合快，形成质量相对较好的修复牙本质。8)由于在中等辐照水平下存在掩蔽效应，CO_2激光的LLLT效应没有得到明确的证实。对于CO_2激光的辐照条件，还需要进一步的研究。少

As reparative dentin-promoting agents, four types of calcium phosphates: hydroxyl-calcium phosphate (HAP), dicalcium phosphate dehydrate (brushite : DCPD), beta-tricalcium phosphate (whitrokite : β-TCP) and octacalcium phosphate (OCT), were mixed with experimental monomer liquid to create materials for experimentally developed direct pulp capping agents and bonding agents of dental substrates. After polymerization, dispersion, shape and composition of calcium phosphates were analyzed by using SEM, EPMA and ICP Atomic Emission Spectrometry.Results obtained were as follows :1) The powder of calcium phosphates in polymerized monomer liquid scattered like dispersed fillers in composite resin. The dispersion of the powder was highly influenced by vibration and trituration during the mixing preparation of the materials.2) Ca showed a relatively high concentration in relation to P. But Mg was present only in a trace amount and was detected only when using line analysis.3) Each calcium phospha … More te showed different elutions of Ca and P. The amount of elutions was affected by the solubility product (Ksp) of each calcium phosphate.4) It was suggested that when the materials were used as direct pulp capping agents, reparative dentin formation was particularly promoted and reliability of wound healing was expected to increase, especially improvement of wound healing in the first stage after capping.5) Calcium phosphates in polymerized pulp capping and bonding agents were found in the vicinity of the exposed pulp. Reparative dentin formation was effectively promoted under the following conditions: calcification promoting effect by direct contact, ionic effect of Ca and P eluted from calcium phosphates and environmental change of the surface of the exposed pulp through the effect of the change in pH.In total twelve types of bonding agents were prepared at a fixed amount of calcium phosphates. The exposed pulp in rats were directly capped with combined use of experimental primers and twelve types of bonding agents. After direct capping of exposed pulp, the rats were sacrificed at the experimental periods of 1, 3, 7, 14 and 28 days. Inflammatory and reparative pulpal changes were examined immunohistochemically and histopathologically under an optical microscope.Results could be summarized as follows :1) After day one, mild inflammatory changes were observed in all groups but they decreased over time (3, 7 days).2) In the groups which used no calcium phosphates, almost no reparative dentin formation was observed on day 14 but a little was observed on day28.3) In the groups which used calcium phosphates, reparative dentin formation was already recognized on day 14 and increased over time up to day 28.4) Reparative dentin formation was clearly affected by the types and concentrations of calcium phosphates. In addition, differences were also observed between the primers.5) In the groups containing calcium phosphates, relatively more reparative dentin formation was observed in the following groups: MB5 (β-TCP 5wt%), MB9 (HAP 5wt%, β-TCP 5wt%), MB1 (HAP 5wt%), MB2 (HAP 1Owt%) and MB3 (β-TCP 5wt%). In general, the groups containing β-TCP showed more advanced reparative dentin formation.6) In experimentally developed primer, MP3 (MB primer containing 5-NMSA 2wt%) showed less inflammatory change than another experimental primer (ABP) containing the antibacterial monomer MDPB. The combination use of MB1 and MP3 showed the least inflammatory change and the most advanced reparative dentin in orthodentin. It was suggested that the combination use of MB1 and MP3 was the most reliable for wound healing in the first stage after direct capping.In the CO_2 laser irradiation groups, Opelaser^<【○!R】> 03 S II SP (Yoshida Dental Mfg Co) was used. After carbonization, the pulpal surface was directly capped with MB.Results could be summarized as follows:1) After day one, slightly stronger inflammatory changes were observed. But they disappeared over time.2) No reparative dentin formation was observed, even after day 14.3) Almost no reparative dentin formation was observed, even after day 28. Instead large amounts of irritative dentin formation was observed on the pulpal wall.4) An irregular type of dentin matrix formation was recognized under the layer of pulpal carbonization.5) The irradiated area of the dentin wall showed the following layers : a carbonization layer, a necrotic layer dyed well with hematoxylin, and a protein denaturation layer dyed well with eosin.6) Carbonization and necrotic layers induced by laser irradiation obstructed reparative dentin formation and delayed wound healing of the pulp. Neither layer worked as an isolation layer from outside stimulation nor as a protective layer of the pulp.7) Irradiation conditions employed were as follows: mild, moderate with an LLLT effect and strong levels. Four types of experimentally developed direct pulp capping agents and bonding agents containing calcium phosphates (MB8, MB9, MB11 and MB12) and an experimentally developed primer (MP) were examined with and without irradiation using a CO_2 laser. There were no significant differences between the groups, and it was confirmed that a mild level of irradiation showed fast would healing properties of the pulp and formed a relatively better quality of reparative dentin.8) By a masking effect at a moderate level of irradiation, an LLLT effect of the CO_2 laser was not clearly confirmed. Regarding the irradiation conditions using the CO_2 laser, more studies are required in the future. Less