DOI QR코드

DOI QR Code

Effect of milling tool wear on the internal fit of PMMA implant interim prosthesis

밀링 공구의 마모가 PMMA 임플란트 임시보철물 변연 및 내면적합도에 미치는 영향

Shin, Mi-sun
신미선

  • Received : 2019.04.19
  • Accepted : 2019.06.12
  • Published : 2019.06.30

Abstract

Purpose: The purpose of this study is to evaluate the effect of CAD/CAM system milling tool wear on the marginal and internal fit of PMMA implant interim prosthesis three-dimensional manner. Methods: A total of 20 crowns were fabricated with CAD/CAM method. Their designs were unified to first molar of the left maxilla. The Customized abutments were prepared and scanned with on optical model scanner. Five crowns were milled by the newly replaced tool (1st milling), and 15 crowns were milled by 2nd, 3rd, 4th milling tool. The marginal and internal fit of 20 interim crowns were measured using the triple-scan protocol. Results: Statistically significant difference was found between the $1^{st}$ milling group ($51.8{\pm}14.6{\mu}m$) and the $3^{rd}$, $4^{th}$ milling group ($128.6{\pm}43.8{\mu}m$, $146.2{\pm}38.1{\mu}m$, respectively) at the distal margins. In the mesial margins, There was a statistically significant difference between the $1^{st}$ milling group ($63.6{\pm}25.9{\mu}m$) and the $3^{rd}$, $4^{th}$ milling group ($137.2{\pm}25.9{\mu}m$, $186.8{\pm}70.6{\mu}m$, respectively). In the distal line angle, significant difference was found between the $1^{st}$, $2^{nd}$, $3^{rd}$ milling groups and the $4^{th}$ milling group. In the mesial axial wall, significant difference was found between the $1^{st}$ milling group ($52.2{\pm}20.3{\mu}m$) and the $3^{rd}$, $4^{th}$ milling groups ($22.8{\pm}8.8{\mu}m$, $7.8{\pm}5.7{\mu}m$). Conclusion: As a result of the experiment, decrease of the marginal and internal fit was statistically significant as the number of machining cycles increased. In order to produce clinically excellent restorations, it is recommandable to consider the condition of the milling tool wear, when designing the restoration with CAD program.

Keywords

CAD/CAM;triple-scan protocol;milling tool;PMMA implant interim prosthesis

References

  1. Al-Omari WM, Shadid R, Abu-Naba'a L, El Masoud B. Porcelain fracture resistance of screw-retained, cement-retained, and screw-cement-retained implantsupported metal ceramic posterior crowns. J Prosthodont 19, 263-273, 2010. https://doi.org/10.1111/j.1532-849X.2009.00560.x
  2. Bayramoglu E, Ozkan YK, Yildiz C. Comparison of marginal and internal fit of press-onmetal and conventional ceramic systems for three-and four-unit implant-supported partial fixed dental prostheses: an in vitro study. J Prosthet Dent 114, 52-58, 2015. https://doi.org/10.1016/j.prosdent.2015.01.002
  3. Burns DR, Beck DA, Nelson SK. Committee on Research in Fixed Prosthodontics of the Academy of Fixed Prosthodontics. A review of selected dental literature on contemporary provisional fixed prosthodontic treatment: report of the Committee on Research in Fixed Prosthodontics of the Academy of Fixed Prosthodontics. J Prosthet Dent, 90(5), 474-497, 2003. https://doi.org/10.1016/S0022-3913(03)00259-2
  4. Cho BM, Lee DJ. A study on cutting characteristics according to cutting direction in ball-end milling. Trans. of KSMTE, 16, 191-197, 2007.
  5. Cho BM, Yoo IS, Lee DJ. A study on the geometric characteristics according to semi-cylindrical tool path in ball-end milling. Trans. Of KSMTE, 5, 362-367, 2009.
  6. Gaugel S, Sripathy P, Haeger A, Meinhard D, Bernthaler T, Lissek F, Kaufeld M, Knoblauch V, Schneider G. A comparative study on tool wear and laminate damage in drilling of carbon-fiber reinforced polymers(CFRP). Composite Structures, 155, 173-183, 2016.
  7. Holmes JR, Bayne SC, Holland GA, Sulik WD. Considerations in measurement of marginal fit. J Prosthet Dent, 62, 405-8, 1989. https://doi.org/10.1016/0022-3913(89)90170-4
  8. Holst S, Karl M, Wichmann M, Matta RE. A new triple-scan protocol for 3D fit assessment of dental restorations. Quintessence Int, 42, 651-657, 2011.
  9. Karaokutan I, Sayin G, Kara O. In vitro study of fracture strength of provisional crown materials. J Adv Prosthodont, 7(1), 27-31, 2015. https://doi.org/10.4047/jap.2015.7.1.27
  10. Lebon, N, Tapie L, Duret F, Attal JP. Understanding dental CAD/CAM for restorations-dental milling machines from a mechanical engineering viewpoint. Part B: labside milling machines. Int J Comput Dent, 19(2), 115-134, 2016.
  11. Matta RE, Schmitt J, Wichmann M. and Holst S. Circumferential fit assessment of CAD/CAM single crowns-a pilot investigation on a new virtual analytical protocol. Quintessence Int, 43, 801-809, 2012.
  12. Nejatidanesh F, Lotfi HR, Savabi O. Marginal accuracy of interim restorations fabricated from four interim autopolymerizing resins. J Prosthet Dent, 95(5), 364-367, 2006. https://doi.org/10.1016/j.prosdent.2006.02.030
  13. Schaefer O, Watts DC, Sigusch BW, Kuepper H, Guentsch A. Marginal and internal fit of pressed lithium disilicate partial crowns in vitro: a three-dimensional analysis of accuracy and reproducibility. Dent Mater, 28(3), 320-326, 2012.
  14. Shin MS, and Lee JH. Marginal and internal fit of all ceramic crown using the replica technique and the triple-scan protocol. J Korean Acad Prosthodont, 55(4), 372-380, 2017. https://doi.org/10.4047/jkap.2017.55.4.372
  15. Song DB. Change in internal fit of dental CADCAM prothesis after continuous milling. D.K.U thesis, 2015.
  16. Thilander B, Odman J, Grondahl K, Friberg B. Osseointegrated implants in adolescents. An alternative in replacing missing teeth? Eur J Orthod, 16, 84-95, 1994. https://doi.org/10.1093/ejo/16.2.84
  17. Won SJ, Li C P, Park K M and Ko TJ. The Exit Hole Burr Generation of CFRP with Ultrasonic Vibration. Journal of the Korean Society of Manufacturing Process Engineers, 16(1), 134-140, 2017.
  18. Yao J, Li J, Wang Y, Huang H. Comparison of the flexural strength and marginal accuracy of traditional and CAD/CAM interim materials before and after thermal cycling. J Prosthet Dent, 112(3), 649-57, 2014. https://doi.org/10.1016/j.prosdent.2014.01.012