The korean journal of orthodontics (대한치과교정학회지)

The Korean Association Of Orthodontists (대한치과교정학회)
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Histologic changes of pulpal tissue after laser-aided ceramic bracket debonding

레이저를 이용한 도재 브라켓 제거 술식 후 치수의 조직학적 변화

  • Kim, Yu-Jeong (Department of Orthodontics, College of Dentistry, Chosun University) ;
  • Lim, Sung-Hoon (Department of Orthodontics, College of Dentistry, Chosun University) ;
  • Yoon, Young-Joo (Department of Orthodontics, College of Dentistry, Chosun University) ;
  • Park, Joo-Cheol (Department of Oral Histology, College of Dentistry, Chosun University) ;
  • Kim, Kwang-Won (Department of Orthodontics, College of Dentistry, Chosun University)
  • 김유정 (조선대학교 치과대학 교정학교실) ;
  • 임성훈 (조선대학교 치과대학 교정학교실) ;
  • 윤영주 (조선대학교 치과대학 교정학교실) ;
  • 박주철 (조선대학교 치과대학 구강조직학교실) ;
  • 김광원 (조선대학교 치과대학 교정학교실)
  • Published : 2004.08.01
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Abstract

Laser-aided debonding has advantages in that the heat produced is localized and controlled, the debonding tool is not heated, and it can be used for the removal of various types of ceramic brackets, regardless of their design. However, the range of safe power usage for laser-aided debonding has not vet been confirmed. The Purpose of this study was to evaluate the histologic changes of pulpal tissue in a rabbit's incisor after Nd-YAG laser-aided ceramic bracket debonding at different levels of power. The result were as follows: 1. At 3-5W Nd-YAG laser power level and 3 seconds of exposure time, the ceramic bracket debonding procedure was not easy. At 5W of power a tie-wing fracture occurred on one bracket during debonding using Weingart plier. The histologic section of pulp represented no adverse changes. 2. At 7-13 W power level and less than 5 seconds of exposure time, the debracketing procedure was done easily and bracket facture did not occur. The histologic section of pulp represented mild and reversible changes. All the results were reversible and no pulpal degeneration or necrosis occurred. Considering the results, it appears that the laser-aided debonding technique is a safe method that does not result in irreversible pulpal changes, softens bracket bonding resin within a saie range of power and exposure time, and is useful for ceramic bracket recycling by lowering the tie- wing fracture rate.

레이저를 이용한 브라켓 제거 술식은 발생하는 열이 국소적이며 조절 가능하고 레이저 조사와 동시에 브라켓 제거시 기구가 뜨거워지지 않으며 브라켓 디자인에 상관없이 여러 형태의 브라켓에 적용이 가능하다는 장점을 가지고 있다. 그러나 아직까지는 치아에 안전한 레이저 강도가 명확히 밝혀지지 못한 상태이다. 따라서 본 연구에서는 토끼의 중절치에 도재 브라켓을 부착한 후 Nd-YAG laser를 여러 가지 강도로 조사한 후 브라켓을 Weingart 겹자로 탈락시켜 5일이 경과한 때의 치수의 조직학적 변화에 대해 관찰한 결과 다음의 결과를 얻었다. 1. Nd-YAG 레이저의 조사 강도가 3-5W이고 조사시간이 3초인 그룹에서 도재 브라켓이 용이하게 제거되지 않았으며 조사 강도가 5W인 그룹에서 한 개의 브라켓에 결찰익면 파절이 나타났다. 이때 치수의 조직학적 검사상 비정상적인 소견은 관찰되지 않았다. 2. Nd-YAG 레이저의 조사 강도가 7-l3W이고 조사시간이 3초인 그룹에서 도재 브라켓을 쉽게 제거할 수 있었으며 브라켓의 파절양상은 보이지 않았다 이때 치수의 조직학적 검사상 경미하고 가역적인 염증 반응이 관찰되었다. 위의 소견은 모두 가역적인 변화이며 치수의 변성이나 괴사의 위험은 없었다 결론적으로 레이저를 이용하여 도재 브라켓을 제거하는 방법은 적절한 범위의 강도와 조사시간 내에서 시행되었을 때 치수의 변성이나 비가역적인 반응을 초래하지 않고 브라켓과 접착 수지의 결합력을 약화시켜 도재 브라켓의 제거를 용이하게 해주며 브라켓 제거 시 파절을 방지하여 도재 브라켓의 재활용 가능성을 높이는 방법이라 생각된다.

Keywords

References

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