Details

Autor(en) / Beteiligte

• Li, Yu-Gang
• Li, Jia-Chun
• Yu, Xiao-Yan
• Hu, Jie
• Li, Zhe
• Cao, Ji-Chao

Titel

Quantitative assessment of aerosol contamination generated during tooth grinding with a speed-increasing handpiece

Ist Teil von

• Journal of dentistry, 2023-12, Vol.139, p.104631-104631, Article 104631

Ort / Verlag

England: Elsevier Ltd

Erscheinungsjahr

2023

Quelle

MEDLINE

Beschreibungen/Notizen

• Tooth grinding produces a significant amount of aerosol particles. The aim of this study was to quantitatively assess particle contamination produced from tooth grinding with a speed-increasing handpiece across a real-world clinical setting. The crowns of all molars were pretreated into cylinders with a uniform cross-section diameter of 10 mm and a height of 5 mm. A novel computer-assisted numerical control system was used to fix the feed rate at 10 mm/min and the grinding depth at 30 μm, and to parametrically study the bur speed: from 20,000 (20 K) to 200,000 (200 K) revolutions per minute (rpm) at 20 K rpm intervals. 5-minute tooth grinding was performed in triplicate at each speed setting in a real dental operation room with the air conditioning off, and the window closed. Three online real-time particle counters (ORPC; TR-8301, TongrenCo.) with six particle-size channels (0.3, 0.5, 1.0, 2.5, 5.0, and 10.0 µm) were placed at 3 positions (0.5 m, 1.0 m, and 1.5 m) to evaluate particle production. All experimental instruments were controlled remotely. The data obtained were statistically analyzed using descriptive statistics and non-parametric tests (Scheirer-Ray-Hare and Kruskal-Wallis/ Dunn-Bonferroni tests, p < 0.05). The concentration level of aerosol particles production during the grinding experiment was elevated above the control group for all conditions, and increased with bur speed at any location (the maximum peak, reaching 5.59 × 107 particles/m3, at 200 K and 1 m), with differences between conditions. We noted that the effect of speed on the increment of particles across different channels compared to the control group was statistically significant among locations (p < 0.001). The simple main effect of location was not significant for the distribution difference of increment in 0.3 µm particles at 120 K (H = 4.314, p = 0.116), 0.5 µm at 180 K (H = 1.855, p = 0.396), and 5 µm at 40 K (H = 1.259, p = 0.533), while increments in other sizes particles at any speed setting showed significant differences (p < 0.05). Out of 171 post hoc pairwise comparisons of location, 130 showed significant differences (p < 0.05), with 50 between 0.5 m and 1.5 m (0.5 m - 1.5 m), and 40 in both the 1.5 m - 1 m and 0.5 m - 1 m. The simple main effect of speed was significant for the distribution difference of particle increment across all channels at any sampling location. In the post hoc pairwise comparisons of speed, there were 810 comparison groups, and those with speed differences below 80 K tended to show non-significant differences (p > 0.05), but all groups with a speed difference above 140 K showed significant differences (p < 0.05). Statistically significant particle contamination was produced using a speed-increasing handpiece, but the contamination level for each experimental condition was reduced to baseline within 30 min, and most particles with a diameter greater than 1 μm produced at low speeds (80 K or lower) tended to settle within 1 m. Our study suggested that the use of a speed-increasing handpiece below 80 K and 30 minutes of fallow time may lead to an adequate reduction in the health effects of particle contamination.