Effect of Milling Speed on the Properties of Zirconia Restorations

Adam J Wallum; Christopher Raimondi; Wen Lien; Wyeth L Hoopes; Kraig S Vandewalle

doi:10.4317/jced.61231

Effect of Milling Speed on the Properties of Zirconia Restorations

J Clin Exp Dent. 2024 Jan 1;16(1):e84-e89. doi: 10.4317/jced.61231. eCollection 2024 Jan.

Authors

Adam J Wallum¹, Christopher Raimondi², Wen Lien³, Wyeth L Hoopes⁴, Kraig S Vandewalle⁵

Affiliations

¹ DMD, MS. Maj, USAF, DC. Director, Restorative Dentistry Advanced Education in General Dentistry Residency. AF Postgraduate Dental School. 1615 Truemper St Joint Base San Antonio - Lackland, TX, USA 78236. Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
² DDS, MS, MS. Lt Col, USAF, DC. Co-Director of Dental Materials Research. USAF Dental Research and Consultation Service. 3650 Chambers Pass, Bldg 3610. Joint Base San Antonio - Fort Sam Houston, TX, USA 78234. Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
³ DMD, MS, MS. Col (ret), USAF, DC. Former Director of Dental Materials Research. USAF Dental Research and Consultation Service. 3650 Chambers Pass, Bldg 3610. Joint Base San Antonio - Fort Sam Houston, TX, USA, 78234. Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA.
⁴ DDS, MS. Lt Col, USAF, DC. Program Director. Advanced Education in General Dentistry Residency. 4102 Pinion Drive. US Air Force Academy, CO, USA 80840. Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
⁵ DDS, MS. Col (ret), USAF, DC. Air Force Consultant in Dental Research. Advanced Education in General Dentistry Residency. AF Postgraduate Dental School. 1615 Truemper St. Joint Base San Antonio - Lackland, TX, USA 78236. Uniformed Services University of the Health Sciences, Bethesda, MD, USA.

Abstract

Background: The purpose of this study was to evaluate the effect of milling speed on the surface roughness, marginal gap, marginal gap volume, marginal offset, and fracture load of zirconia restorations.

Material and methods: A mandibular molar #30 typodont tooth was digitally scanned and an ideal crown preparation for a zirconia restoration was digitally created. A single master model die of the crown preparation was milled out of a resin material. The master die was scanned, and a final restoration was designed using the bio-copy feature of the typodont tooth. Ten zirconia restorations were milled (CEREC Primemill, Dentsply Sirona) per each of three milling speeds (super-fast, fine, and extra-fine), sintered, and seated on the master die. Surface roughness, marginal gap, marginal gap volume, and marginal offset were measured using a non-contact profilometer. Then, all restorations were cemented to the dies and loaded to failure in a material testing device. Data were analyzed with one-way ANOVA and Tukey's post hoc tests per property (alpha=0.05).

Results: Super-fast milling speed resulted in restorations with statistically significant greater surface roughness and marginal gap volume compared to fine and extra-fine milling speeds. No significant difference in marginal gap, marginal offset, and fracture load were found based on milling speed.

Conclusions: Zirconia restorations milled at slower speeds may result in similar or slightly better properties compared to super-fast speed. Key words:Milling speed, properties, zirconia restorations.