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

CO2 激光照射和使用实验开发的高分子盖髓剂直接盖髓的效果：暴露牙髓的伤口愈合机制。

基本信息

批准号：
15390578
负责人：
KATOH Yoshiroh
金额：
$ 8万
依托单位：
The Nippon Dental University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2006
项目状态：
已结题

项目摘要

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

作为修复性牙本质促进剂，四种类型的磷酸钙：羟基磷酸钙（HAP）、磷酸氢钙钙（透钙磷石：DCPD）、β-磷酸三钙（whitrokite：β-TCP）和磷酸八钙（OCT）与实验单体液体混合，以创建用于实验开发的直接盖髓剂和牙科基质粘结剂的材料。采用扫描电镜、电子探针和电感耦合等离子体原子发射光谱仪对聚合后磷酸钙的分散性、形貌和组成进行了分析，结果表明：1）磷酸钙粉末在聚合单体液中呈分散填料状分散在复合树脂中;在混合制备过程中，振动和研磨对粉末的分散有很大的影响。2）Ca相对于P显示出相对较高的浓度，但Mg仅以痕量存在，并且仅在使用线性分析时才被检测到。3）每个磷酸钙都具有较高的浓度。 ...更多信息结果表明，不同磷酸钙的溶度积（Ksp）对钙、磷的溶出量有不同的影响。4）当材料用作直接盖髓剂时，特别能促进修复性牙本质的形成，并有望提高伤口愈合的可靠性。特别是在盖髓后的第一阶段促进伤口愈合。5）在暴露的牙髓附近发现聚合盖髓和粘合剂中的磷酸钙。在以下条件下，有效地促进修复性牙本质的形成：直接接触的钙化促进作用，从磷酸钙洗脱的Ca和P的离子效应和暴露的牙髓表面的环境变化，通过pH值的变化的影响。采用实验引物和12种粘接剂联合应用，直接盖髓。直接盖髓后，分别于实验第1、3、7、14和28天处死大鼠。在光学显微镜下观察牙髓炎性和修复性改变的化学和组织病理学变化。1）第一天后，在所有组中观察到轻度炎症变化，但它们随着时间的推移而减少。（3、7天）2）不使用磷酸钙组在第14天几乎无修复性牙本质形成，而在第28天有少量修复性牙本质形成。3）使用磷酸钙组，修复性牙本质形成在第14天已经被识别，并且随着时间的推移而增加，直到第28天。磷酸钙的种类和浓度明显影响修复性牙本质的形成。5）在含磷酸钙组中，MB 5（β-TCP 5wt%）、MB 9（HAP 5wt%、β-TCP 5wt%）、MB 1（HAP 5wt%）、MB 2（HAP 1Owt%）和MB 3（β-TCP 5wt%）的修复性牙本质形成相对较多。6）在实验开发的引物中，MP3（含2wt% 5-NMSA的MB引物）比另一种含抗菌单体MDPB的实验引物（ABP）显示出更少的炎症变化。MB 1和MP3联合使用时，在正牙本质中的炎性变化最小，修复性牙本质最先进。结果表明，在直接盖帽后的第一阶段，MB 1和MP 3联合应用对创面愈合最为可靠。使用R]> 03 S II SP（Yoshida Dental Mfg Co）。实验结果如下：1）第1天，牙髓组织出现较强的炎症反应。但随着时间的推移，它们消失了。2）没有观察到修复性牙本质形成，即使在14天后。3）几乎没有观察到修复性牙本质形成，即使在28天后。4）牙髓碳化层下可见不规则的牙本质基质形成。5）照射区牙本质壁有以下几层：炭化层、苏木素染色良好的坏死层、6）激光照射引起的碳化和坏死层阻碍修复性牙本质的形成，延迟牙髓创伤愈合。这两层都不能作为与外部刺激的隔离层，也不能作为牙髓的保护层。7）所用的辐照条件如下：轻度、中度，具有LLLT效应和强水平。本文用CO_2激光对四种实验室研制的含磷酸钙的直接盖髓剂和粘结剂（MB 8、MB 9、MB 11和MB 12）以及实验室研制的底涂剂（MP）进行了辐照和非辐照的对比研究。实验结果表明，轻度照射能使牙髓快速愈合，形成质量相对较好的修复性牙本质。（8）通过中度照射的掩蔽效应，CO_2激光的LLLT效应未得到明确证实。关于CO_2激光的辐照条件，还需要进一步的研究。少