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Mafrici C, Kingston M, Grice R, Abbott PV. The Effect of Water Coolant and Bur Type on Pulp Temperature When Removing Tooth Structure and Restorative Dental Materials. Oper Dent 2024; 49:91-97. [PMID: 38057997 DOI: 10.2341/23-033-l] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/01/2023] [Indexed: 12/08/2023]
Abstract
OBJECTIVE The aim was to compare intrapulp temperature (IPT) changes when flat-fissure diamond burs and pear-shaped tungsten carbide burs were used to cut tooth structure, amalgam, and composite resin with and without water coolant. METHODS Thermocouples were inserted into the pulp chamber of extracted intact mandibular molars. The thermocouples were connected to an electronic thermometer that detects temperature every second to an accuracy of 0.1°C. IPT changes were recorded while using a high-speed handpiece during MOD cavity preparations (n=40), composite resin removal (n=40), and amalgam removal (n=40). A two-way ANOVA was used for each procedure to test for the effect of bur (pear-shaped tungsten carbide vs flat-fissured diamond) and water coolant (on vs off), with significant main effects (α=0.05) further analyzed using Tukey's multiple comparison test. RESULTS During MOD cavity preparation, water coolant reduced changes in IPT (0.03±0.27°C) compared to no water coolant (1.27±0.29°C) when tungsten carbide burs were used (p<0.05) but not when diamond burs were used. During composite resin removal, tungsten carbide burs had less changes in IPT (0.55±0.18°C) compared to diamond burs (1.66±0.50°C) with no water coolant (p<0.05). Water coolant also reduced changes in IPT (0.09±0.14°C) compared to no water coolant (1.66±0.50°C) when diamond burs were used (p<0.01). Water coolant did not significantly affect IPT when tungsten carbide burs were used. During amalgam removal, tungsten carbide burs had lower changes in IPT (0.56±0.15°C) compared to diamond burs (1.88±0.43°C) with no water coolant (p<0.05). Water coolant also significantly reduced changes in IPT (0.71±0.2°C) compared to no water coolant (1.88±0.43°C) when diamond burs were used (p<0.05) but not when tungsten carbide burs were used. CONCLUSIONS Water coolant reduced IPT changes when drilling tooth structure with tungsten carbide burs, but not when removing amalgam or composite. Conversely, water coolant reduced IPT changes when drilling with flat fissure diamond burs to remove amalgam and composite, but not when removing tooth structure. When amalgam and composite were removed without water coolant, the tungsten carbide burs resulted in lower IPT changes than when flat fissure diamond burs were used in the same way.
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Affiliation(s)
- C Mafrici
- Christopher Mafrici, BSc(Hons), DMD, UWA Dental School, The University of Western Australia, Nedlands, WA, Australia
| | - M Kingston
- Morgan Kingston, BSc(Hons), DMD, UWA Dental School, The University of Western Australia, Nedlands, WA, Australia
| | - R Grice
- Ryan Grice, BMedSc, DMD, UWA Dental School, The University of Western Australia, Nedlands, WA, Australia
| | - P V Abbott
- *Paul V. Abbott, BDSc, MDS, DDSc, FRACDS(Endo), emeritus professor, UWA Dental School, The University of Western Australia, Nedlands, WA, Australia
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Li YG, Li JC, Yu XY, Hu J, Li Z, Cao JC. Quantitative assessment of aerosol contamination generated during tooth grinding with a speed-increasing handpiece. J Dent 2023; 139:104631. [PMID: 37495202 DOI: 10.1016/j.jdent.2023.104631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 06/29/2023] [Accepted: 07/21/2023] [Indexed: 07/28/2023] Open
Abstract
OBJECTIVES 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. METHODS All molar crowns were pretreated into cylinders with a uniform size. A novel computer-assisted numerical control system was used to parametrically study the bur speed: from 20,000 (20 K) to 200 K rpm at 20 K rpm intervals. 5-minute tooth grinding was performed in triplicate at each speed setting. Three online real-time particle counters (ORPC; TR-8301, TongrenCo.) were placed at 3 positions (0.5, 1, 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). RESULTS 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. 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). CONCLUSIONS 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 1üm produced at low speeds (80 K or lower) tended to settle within 1 m. CLINICAL RELEVANCE Our study suggested that the use of a speed-increasing handpiece below 80 K and 30 min of fallow time may lead to an adequate reduction in the health effects of particle contamination.
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Affiliation(s)
- Yu-Gang Li
- School of Mechanical Engineering, Guizhou University, Guiyang, China; Guizhou Equipment Manufacturing Polytechnic, Guiyang, China
| | - Jia-Chun Li
- School of Mechanical Engineering, Guizhou University, Guiyang, China.
| | - Xiao-Yan Yu
- Guiyang Hospital of Stomatology, Guiyang, China
| | - Jie Hu
- School of Mechanical Engineering, Guizhou University, Guiyang, China
| | - Zhe Li
- School of Life Sciences, Guizhou Normal University, Guiyang, China
| | - Ji-Chao Cao
- College of Mechanical and Vehicle Engineering, Hunan University, Changsha, China
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Kincses D, Jordáki D, Szebeni D, Kunsági-Máté S, Szalma J, Lempel E. Effect of Ceramic and Dentin Thicknesses and Type of Resin-Based Luting Agents on Intrapulpal Temperature Changes during Luting of Ceramic Inlays. Int J Mol Sci 2023; 24:ijms24065466. [PMID: 36982546 PMCID: PMC10057599 DOI: 10.3390/ijms24065466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/06/2023] [Accepted: 03/10/2023] [Indexed: 03/16/2023] Open
Abstract
The adhesive cementation of ceramic inlays may increase pulpal temperature (PT) and induce pulpal damage due to heat generated by the curing unit and the exothermic reaction of the luting agent (LA). The aim was to measure the PT rise during ceramic inlay cementation by testing different combinations of dentin and ceramic thicknesses and LAs. The PT changes were detected using a thermocouple sensor positioned in the pulp chamber of a mandibular molar. Gradual occlusal reduction obtained dentin thicknesses of 2.5, 2.0, 1.5, and 1.0 mm. Light-cured (LC) and dual-cured (DC) adhesive cements and preheated restorative resin-based composite (RBC) were applied to luting of 2.0, 2.5, 3.0, and 3.5 mm lithium disilicate ceramic blocks. Differential scanning calorimetry was used to compare the thermal conductivity of dentin and ceramic slices. Although ceramic reduced heat delivered by the curing unit, the exothermic reaction of the LAs significantly increased it in each investigated combination (5.4–7.9 °C). Temperature changes were predominantly influenced by dentin thickness followed by LA and ceramic thickness. Thermal conductivity of dentin was 24% lower than that of ceramic, and its thermal capacity was 86% higher. Regardless of the ceramic thickness, adhesive inlay cementation can significantly increase the PT, especially when the remaining dentin thickness is <2 mm.
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Affiliation(s)
- Dóra Kincses
- Department of Restorative Dentistry and Periodontology, Faculty of Dentistry, University of Pécs Medical School, PTüzér Street 1, 7623 Pécs, Hungary
| | - Dóra Jordáki
- Department of Restorative Dentistry and Periodontology, Faculty of Dentistry, University of Pécs Medical School, PTüzér Street 1, 7623 Pécs, Hungary
| | - Donát Szebeni
- Department of Restorative Dentistry and Periodontology, Faculty of Dentistry, University of Pécs Medical School, PTüzér Street 1, 7623 Pécs, Hungary
| | - Sándor Kunsági-Máté
- Department of Organic and Medicinal Chemistry, Faculty of Pharmacy, University of Pécs, Honvéd Street 1, 7624 Pécs, Hungary
- János Szentágothai Research Center, Ifjúság Street 20, 7624 Pécs, Hungary
| | - József Szalma
- Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, University of Pécs Medical School, Tüzér Street 1, 7623 Pécs, Hungary
| | - Edina Lempel
- Department of Restorative Dentistry and Periodontology, Faculty of Dentistry, University of Pécs Medical School, PTüzér Street 1, 7623 Pécs, Hungary
- Correspondence: ; Tel.: +36-(72)-536402
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Vernon JJ, Lancaster PE, Black EVI, Devine DA, Fletcher L, Wood DJ, Nattress BR. Increased Handpiece Speeds without Air Coolant: Aerosols and Thermal Impact. J Dent Res 2023; 102:53-60. [PMID: 36203309 PMCID: PMC9780751 DOI: 10.1177/00220345221123253] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
This study assessed the impact of increased speed of high-speed contra-angle handpieces (HSCAHs) on the aerosolization of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) surrogate virus and any concomitant thermal impact on dental pulp. A bacteriophage phantom-head model was used for bioaerosol detection. Crown preparations were performed with an NSK Z95L Contra-Angle 1:5 (HSCAH-A) and a Bien Air Contra-Angle 1:5 Nova Micro Series (HSCAH-B) at speeds of 60,000, 100,000, and 200,000 revolutions per minute (rpm), with no air coolant. Bioaerosol dispersal was measured with Φ6-bacteriophage settle plates, air sampling, and particle counters. Heating of the internal walls of the pulp chambers during crown preparation was assessed with an infrared camera with HSCAH-A and HSCAH-B at 200,000 rpm (water flows ≈15 mL min-1 and ≈30 mL min-1) and an air-turbine control (≈23.5 mL min-1) and correlated with remaining tissue thickness measurements. Minimal bacteriophage was detected on settle or air samples with no notable differences observed between handpieces or speeds (P > 0.05). At all speeds, maximum settled aerosol and average air detection was 1.00 plaque-forming units (pfu) and 0.08 pfu/m3, respectively. Irrespective of water flow rate or handpiece, both maximum temperature (41.5°C) and temperature difference (5.5°C) thresholds for pulpal health were exceeded more frequently with reduced tissue thickness. Moderate and strong negative correlations were observed based on Pearson's correlation coefficient, between remaining dentine thickness and either differential (r = -0.588) or maximum temperature (r = -0.629) measurements, respectively. Overall, HSCAH-B generated more thermal energy and exceeded more temperature thresholds compared to HSCAH-A. HSCAHs without air coolant operating at speeds of 200,000 rpm did not increase bioaerosolization in the dental surgery. Thermal risk is variable, dependent on handpiece design and remaining dentine thickness.
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Affiliation(s)
- J J Vernon
- Division of Oral Biology, School of Dentistry, University of Leeds, Leeds, UK
| | - P E Lancaster
- Division of Restorative Dentistry, School of Dentistry, University of Leeds, Leeds, UK
| | - E V I Black
- Division of Oral Biology, School of Dentistry, University of Leeds, Leeds, UK
| | - D A Devine
- Division of Oral Biology, School of Dentistry, University of Leeds, Leeds, UK
| | - L Fletcher
- School of Civil Engineering, University of Leeds, Leeds, UK
| | - D J Wood
- Division of Oral Biology, School of Dentistry, University of Leeds, Leeds, UK
| | - B R Nattress
- Division of Restorative Dentistry, School of Dentistry, University of Leeds, Leeds, UK
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Dental high-speed handpiece and ultrasonic scaler aerosol generation levels and the effect of suction and air supply. Infect Control Hosp Epidemiol 2022:1-8. [DOI: 10.1017/ice.2022.196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Abstract
Objective:
Exposure to aerosol spray generated by high-speed handpieces (HSHs) and ultrasonic scalers poses a significant health risk to oral health practitioners from airborne pathogens. Aerosol generation varies with different HSH designs, but to date, no study has measured this.
Materials and methods:
We measured and compared aerosol generation by (1) dental HSHs with 3 different coolant port designs and (2) ultrasonic scalers with no suction, low-volume evacuation (LVE) or high-volume evacuation (HVE). Measurements used a particle counter placed near the operator’s face in a single-chair, mechanically ventilated dental surgery. Volume concentrations of aerosol, totaled across a 0.3–25-µm size range, were compared for each test condition.
Results:
HSH drilling and scaling produced significantly high aerosol levels (P < .001) with total volume concentrations 4.73×108µm3/m3 and 4.18×107µm3/m3, respectively. For scaling, mean volume of aerosol was highest with no suction followed by LVE and HVE (P < .001). We detected a negative correlation with both LVE and HVE, indicating that scaling with suction improved operator safety. For drilling, simulated cavity preparation with a 1-port HSH generated the most aerosol (P < .01), followed by a 4-port HSH. Independent of the number of cooling ports, lack of suction caused higher aerosol volume (1.98×107 µm3/m3) whereas HVE significantly reduced volume to −4.47×105 µm3/m3.
Conclusions:
High concentrations of dental aerosol found during HSH cavity preparation or ultrasonic scaling present a risk of infection, confirming the advice to use respiratory PPE. HVE and LVE both effectively reduced aerosol generation during scaling, whereas the new aerosol-reducing ‘no air’ function was highly effective and can be recommended for HSH drilling.
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