A STUDY ON THE MECHANISUM OF TOOTH FRACTURE DUE TO MASTICATORY PRESSURE

咀嚼压力导致牙齿折断机制的研究

• 批准号: 12671859
• 负责人: TAKATSU Toshio
• 金额: $ 2.11万
• 依托单位: OHU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12671859/
• 关键词: tooth fracture; fractured tooth; fatigue test; fatigue fracture

This study was performed on the following two parts.1. Experimental fatigue fracture test using the compressive stress cycling apparatusOcclusal cavities were mesio-dostally or bucco-lingually prepared in the human extracted upper premolars. Strain gauges were attached to the tooth 1mm below the cavity. Then, increasing compressive load was repeatedly applied to the cavity until the tooth fractured, using the fatigue test apparatus originally designed in our department. Measurements were performed on strained amount of the tooth, stress repeated number and final load value on fracture. Consequently, two types of the cavity were found remarkably differed in fracture resistance to the repeated stress, namely up to approximately 14.0×10^4 cycles for mesio-distal cavity and approximately 1.1×10^3 cycles for the bucco-lingual cavity. SEM observation of the experimentally fractured surface indicated the seemingly brittle and rapid fracture patterns.2. Observation of the fractured tooth fragments in vivoSixteen subjects in total were used. Most of them had been endodonticly treated and restored. They were subjected to the optical microscopy, obtaining the finding that most of them fractured in rapid producing the gross and brittle fracture patterns.

本研究主要从以下两个部分展开。用压应力循环装置进行实验性疲劳断裂试验在人拔除的上颌前磨牙上，近牙合或颊舌向形成咬合空洞。在洞下1 mm处的牙齿上安装应变片。然后，使用我科自行设计的疲劳试验机，对牙洞反复施加不断增加的压缩载荷，直至牙齿折断。测量牙齿的应变量、应力重复次数和断裂时的最终载荷值。结果发现，两种类型的窝洞对重复应力的抗力有显著差异，即近远中窝洞高达14.0×10~(-4)周次，颊舌窝洞约1.1×10~(-3)周次。对实验断口的扫描电子显微镜观察表明，断口具有明显的脆性和快速断口特征。活体断牙观察共16例受试者。其中大部分已接受根管治疗和修复。对它们进行了光学显微镜观察，发现它们大多是快速断裂的，产生了粗大而脆性的断口图案。

项目成果

Toshio Takatsu, Nobuo Kouroku, Katsuaki Iwami, Tsunekazu Shono and Masaaki Satoh: "A fractographical Study of fractured tooth -- Effect of a pair of removed fragments before and after ultrasonic cleansing"Japanese Journal of Conservative Dentistry. Vol.41

Toshio Takatsu、Nobuo Kouroku、Katsuaki Iwami、Tsunekazu Shono 和 Masaaki Satoh：“折断牙齿的断口研究——超声波清洁前后一对去除碎片的影响”日本保守牙科杂志。

Toshio Takatsu and Nobuo Kouroku: "A study on saving a vertically fractured molar tooth -- Effect of a simple method to manage a vertical root fracture of a molar"Japaneses Journal of Conservative Dentistry. Vol.39-No.6. 1316-1323 (1996)

Toshio Takatsu 和 Nobuo Kouroku：“挽救垂直断裂的磨牙的研究——处理磨牙垂直根部断裂的简单方法的效果”日本保守牙科杂志。

Toshio Takatsu, Toshimoto Yamada, Shigehisa Inokoshi, Morioki Fujitani and Masaaki Sato: "A study for saving a fractured Tooth -- Diagnosis and treatment of a vital molar exhibiting a vertical root fracture"Jaopanese Journal of Conservative Dentistry. Vol

Toshio Takatsu、Toshimoto Yamada、Shigehisa Inokoshi、Morioki Fujitani 和 Masaaki Sato：“拯救断裂牙齿的研究——显示垂直牙根断裂的重要磨牙的诊断和治疗”日本保守牙科杂志。

菊井 徹哉, 高録 伸郎, 佐藤 暢昭, 高津 寿夫: "歯の咬合性破壊に関する研究-試作疲労試験システムを用いた窩洞形成歯の疲労破折耐久性"日本歯科保存学雑誌. 46. 408-417 (2003)

Tetsuya Kikui、Nobuo Takanori、Nobuaki Sato、Hisao Takatsu：“使用原型疲劳测试系统研究牙齿咬合断裂 - 空腔预备牙齿的疲劳断裂耐久性”日本保守牙科杂志 46. 408-417 (2003)。