Cuylear Darnell L, Fu Moyu L, Chau Justin C, Kharbikar Bhushan, Kazakia Galateia J, Jheon Andrew, Habelitz Stefan, Kapila Sunil D, Desai Tejal A
Graduate Program in Oral and Craniofacial Sciences, School of Dentistry, University of California, San Francisco (UCSF), San Francisco, CA, United States.
Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco (UCSF), San Francisco, CA, United States.
bioRxiv. 2024 Jul 30:2024.07.29.605671. doi: 10.1101/2024.07.29.605671.
Orthodontic relapse is one of the most prevalent concerns of orthodontic therapy. Relapse results in patients' teeth reverting towards their pretreatment positions, which increases the susceptibility to functional problems, dental disease, and substantially increases the financial burden for retreatment. This phenomenon is thought to be induced by rapid remodeling of the periodontal ligament (PDL) in the early stages and poor bone quality in the later stages. Current therapies, including fixed or removable retainers and fiberotomies, have limitations with patient compliance and invasiveness. Approaches using biocompatible biomaterials, such as calcium phosphate polymer-induced liquid precursors (PILP), is an ideal translational approach for minimizing orthodontic relapse. Here, post-orthodontic relapse is reduced after a single injection of high concentration PILP (HC-PILP) nanoclusters by altering PDL remodeling in the early stage of relapse and improving trabecular bone quality in the later phase. HC-PILP nanoclusters are achieved by using high molecular weight poly aspartic acid (PASP, 14 kDa) and poly acrylic acid (PAA, 450 kDa), which resulted in a stable solution of high calcium and phosphate concentrations without premature precipitation. results show that HC-PILP nanoclusters prevented collagen type-I mineralization, which is essential for the tooth-periodontal ligament (PDL)-bone interphase. experiments show that the PILP nanoclusters minimize relapse and improve the trabecular bone quality in the late stages of relapse. Interestingly, PILP nanoclusters also altered the remodeling of the PDL collagen during the early stages of relapse. Further experiments showed that PILP nanoclusters alter the fibrillogenesis of collagen type-I by impacting the protein secondary structure. These findings propose a novel approach for treating orthodontic relapse and provide additional insight into the PILP nanocluster's structure and properties on collagenous structure repair.
正畸复发是正畸治疗中最普遍关注的问题之一。复发会导致患者牙齿恢复到治疗前的位置，这增加了出现功能问题、牙齿疾病的易感性，并大幅增加了再次治疗的经济负担。这种现象被认为是由早期牙周膜（PDL）的快速重塑以及后期骨质量不佳所诱发的。当前的治疗方法，包括固定或可摘保持器以及纤维切断术，在患者依从性和侵入性方面存在局限性。使用生物相容性生物材料的方法，如磷酸钙聚合物诱导液体前驱体（PILP），是一种将正畸复发降至最低的理想转化方法。在此，通过在复发早期改变牙周膜重塑并在后期改善小梁骨质量，单次注射高浓度PILP（HC - PILP）纳米团簇后正畸后复发得以减少。HC - PILP纳米团簇是通过使用高分子量聚天冬氨酸（PASP，14 kDa）和聚丙烯酸（PAA，450 kDa）实现的，这导致了高钙和高磷浓度的稳定溶液且无过早沉淀。结果表明，HC - PILP纳米团簇阻止了I型胶原矿化，而I型胶原矿化对于牙齿 - 牙周膜（PDL） - 骨界面至关重要。实验表明，PILP纳米团簇在复发后期将复发降至最低并改善了小梁骨质量。有趣的是，PILP纳米团簇在复发早期也改变了牙周膜胶原的重塑。进一步的实验表明，PILP纳米团簇通过影响蛋白质二级结构改变了I型胶原的原纤维形成。这些发现提出了一种治疗正畸复发的新方法，并为PILP纳米团簇在胶原结构修复方面的结构和特性提供了更多见解。
