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Dento Maxillo Facial Radiology Oct 2023To compare cylindrical and convex triangular field-of-views (FOVs) concerning the magnitude of artefacts from high-density materials in cone-beam CT (CBCT).
OBJECTIVE
To compare cylindrical and convex triangular field-of-views (FOVs) concerning the magnitude of artefacts from high-density materials in cone-beam CT (CBCT).
METHODS AND MATERIALS
Cylinders of amalgam, chromium-cobalt, titanium, and zirconia were individually placed in the anterior and posterior regions of a polymethylmethacrylate phantom and scanned using cylindrical and convex triangular FOVs of the Veraview X800 CBCT device. Using the Image J software, 15 square regions of interest (ROIs) were placed in the axial reconstruction around the middle level of the cylinder and at distances of 0.5, 1.0, and 1.5 cm from the centre of the cylinder. Mean grey value and standard deviation of each ROI were averaged for each distance and subtracted from the values of a control ROI to calculate the magnitude of the artefacts by the grey value mean difference (GVMD) and grey value standard deviation (GVSD). Multiway analysis of variance with Tukey test with a significance level of 5% evaluated the effect of the shape of the FOV, position inside the FOV, high-density material, and the distance of the artefact from the material.
RESULTS
The convex triangular FOV increased the GVSD for all materials in the anterior and posterior regions at 0.5 cm compared to the cylindrical FOV ( < 0.0001). The convex triangular FOV showed greater GVMD for chromium-cobalt and zirconium in the anterior region and all materials in the posterior region at all distances ( < 0.0001).
CONCLUSION
The FOV shape influences the magnitude of artefacts from high-density materials. The convex triangular FOV showed greater artefact magnitude with variability among the high-density materials, region in the FOV, and distance from the material.
Topics: Humans; Cone-Beam Computed Tomography; Artifacts; Cobalt; Chromium; Phantoms, Imaging
PubMed: 37493606
DOI: 10.1259/dmfr.20230147 -
European Journal of Radiology Sep 2023To test local grey-scale changes on dental bitewing radiographs near filling margins for image acquisition. Forty approximal preparations in caries-free amalgam filled...
To test local grey-scale changes on dental bitewing radiographs near filling margins for image acquisition. Forty approximal preparations in caries-free amalgam filled teeth and bitewing radiographs were acquired under standardized conditions applying four techniques. Film-based analog radiographs were digitized using flat-bed scanner (FDR). Phosphor-plate computed radiographs (PCR) were directly acquired by scanning VistaScan imaging plates. Image quality was tested using Preset Filter (PF) or manually applied IntraOral Fine Filter (IF) to enhance digital images. Local changes from digital imaging processing were assessed by comparing the margin-near (MN) and margin-far (MF) zone by a multivariate repeated measurements analysis. All images were acquired with 8-bit depth (256 shades). Dentine was displayed in 79 shades for FDR and 54 shades for PCR. PF or IF locally modify bitewing radiographs by darkening marginal dentine by 8 or 29 shades, respectively. The sharpest display of the margin (shades per pixel) from dentine to filling was found for IF (26.2), followed by FDR (23.2), PF (15.3) and PCR (8.3). Computed radiography with phosphor plates generate more homogeneous images compared to flatbed-digitized film-based radiographs. The filling margin was sharpest represented with the IF filter at the detriment of an artificial darkening of the dentine near the margin of the filling. Contour artifacts by filters have the potential to confound diagnosis of secondary caries. Algorithms and filters for sensor data processing, causing local changes above 2% of the dynamic range by non-continuous mathematical functions, should only be applied with caution, manually when diagnosing and reversibly.
Topics: Humans; Radiographic Image Enhancement; Radiography, Dental, Digital; Radiography, Bitewing; Artifacts; Radiography; X-Ray Intensifying Screens
PubMed: 37556885
DOI: 10.1016/j.ejrad.2023.111004 -
Brazilian Oral Research 2023A multicenter, randomized controlled clinical trial evaluated the effectiveness of two treatments for deep caries lesions in permanent molars - selective caries removal... (Randomized Controlled Trial)
Randomized Controlled Trial
A multicenter, randomized controlled clinical trial evaluated the effectiveness of two treatments for deep caries lesions in permanent molars - selective caries removal (SCR) to soft dentin with restoration in a single visit, and stepwise excavation (SW) - regarding pulp vitality for a 5-year follow-up period. The present study aimed to determine the cost-effectiveness of these treatments. Treatments were conducted in two Brazilian cities (Brasília and Porto Alegre). At baseline, 299 permanent molars (233 patients) were treated and 229 teeth (174 patients) were evaluated after 5 years. The discounted cash flow method was adopted. The total cost of each treatment was calculated, and the failure cost (endodontic treatment + restoration) was added to the final cost, according to the 5-year failure rates of each therapy (20% for SCR and 44% for SW). A public health service unit composed of three dentists in 4-hour work shifts was used to calculate the monetary value of the treatments, assuming a total of 528 treatments/month. Considering the 229 teeth evaluated after 5 years (115 SCR and 114 SW), SCR provided savings of 43% (amalgam) and 41% (resin composite) per treatment, compared to SW. The SCR technique provides benefits for public finances (direct economy) and for public health services (increase in the number of treatments performed). Considering that maximizing profit and reducing costs are powerful motivating factors for adopting a certain treatment, this study provides data to better support the decision-making process, regarding the management of deep caries lesions in permanent molars.
Topics: Humans; Cost-Benefit Analysis; Dental Caries Susceptibility; Dental Care; Molar; Brazil
PubMed: 37672417
DOI: 10.1590/1807-3107bor-2023.vol37.0083 -
Oral Radiology Oct 2023The aim of this study was to compare and evaluate diagnostic accuracy of two different CBCT scan modes and digital bitewing radiography for detection of recurrent caries...
Comparison of accuracy cone-beam computed tomography and digital bitewing radiography for detection of recurrent caries under various restorative materials: in vitro study.
OBJECTIVE
The aim of this study was to compare and evaluate diagnostic accuracy of two different CBCT scan modes and digital bitewing radiography for detection of recurrent caries under five different restorative materials, and determine the relationship between the types of restorative materials.
MATERIALS AND METHODS
In this in vitro study, 200 caries-free upper and lower premolars and molars were selected. A standard deep Class II cavities was created in the middle of the mesial surface of all teeth. In 100 teeth of the experimental and control groups, secondary caries was artificially demineralized. All teeth were filled with five types of restorative material including two types of conventional composite resins, flow composite resin, glass ionomer and amalgam. The teeth were imaged with high resolution (HIRes) and standard CBCT scan modes and digital bitewing. The AUC, sensitivity, specificity and areas under the ROC curve were calculated and verified through SPSS.
RESULTS
CBCT technique was the best option in diagnosing recurrent caries. The diagnostic accuracy and specificity of HIRes CBCT scan mode was significantly higher than standard mode (P = 0.031) and bitewing (P = 0.029) for detection of recurrent caries, especially under composite group. There were no significant differences in accuracy value of bitewing and standard CBCT scan mode.
CONCLUSION
CBCT showed higher accuracy and specificity on the detection of recurrent caries which was more accurate than bitewing radiography. The HIRes CBCT scan mode achieved the highest accuracy and performed the best in recurrent caries detection.
Topics: Sensitivity and Specificity; Radiography, Bitewing; ROC Curve; Molar; Cone-Beam Computed Tomography
PubMed: 37335388
DOI: 10.1007/s11282-023-00690-x -
BMC Oral Health Jul 2023Paediatric dentistry is a branch of dental specialty that focuses on dental care for children from infancy through adolescence. However, there is no standardised...
BACKGROUND
Paediatric dentistry is a branch of dental specialty that focuses on dental care for children from infancy through adolescence. However, there is no standardised national undergraduate paediatric dental curriculum in Malaysia. The present study aimed to identify relevant topics for undergraduate paediatric dental curricula and to determine the appropriate cognitive and psychomotor levels for each topic based on the consensus among paediatric dental experts.
METHODS
Potential relevant undergraduate paediatric dentistry topics were initially drafted and revised according to the revised national competency statement. The final draft included 65 topics clustered under 18 domains. A fuzzy Delphi method was used and experts who fulfilled the inclusion criteria were invited to anonymously ranked the importance of relevant topics using a five-point Likert scale and proposed suitable cognitive and psychomotor levels for each topic. Fuzzy evaluation was then performed, and experts were considered to have reached a consensus if the following three conditions were achieved: (a). the difference between the average and expert rating data was ≤ 0.2; (b). the average expert consensus was ˃70%; and (c). the average fuzzy number was ≥ 0.5. Subsequently, the mean ratings were used to determine the cognitive and psychomotor levels.
RESULTS
20 experts participated in the survey. 64 out of 65 paediatric dentistry topics were deemed acceptable. The average fuzzy number ranged from 0.36 to 0.85, while the average Likert score ranged from 3.05 to 5.00. The topic "Dental amalgam" was rejected based on expert consensus since the average fuzzy number was 0.36. The most significant topic was "Pit and fissure sealant", followed by "Preventive advice", "Early childhood caries", "Dental caries in children & adolescent", "Management of dental caries in paediatric patients", and "Consent" which were equally ranked as the second most important topics. According to Bloom's and Simpson's taxonomies, most of the paediatric dentistry topics were rated adequate for undergraduate students at the cognitive level of "Apply" (C3) and a psychomotor level of "Guided response" (P3).
CONCLUSION
The current study successfully identified relevant undergraduate paediatric dentistry topics using the fuzzy Delphi method, which can facilitate future educators to improve existing Malaysian undergraduate paediatric dental curricula.
Topics: Humans; Child; Child, Preschool; Adolescent; Consensus; Dental Caries; Students; Curriculum; Education, Dental
PubMed: 37407955
DOI: 10.1186/s12903-023-03130-8 -
The Journal of Craniofacial Surgery May 2024The presence of foreign bodies in the mandible is not listed as a risk factor or absolute contraindication for implant rehabilitation. However, possible complications...
The presence of foreign bodies in the mandible is not listed as a risk factor or absolute contraindication for implant rehabilitation. However, possible complications caused by foreign bodies, such as infection and cyst formation, could lead to implant failure. The authors report a case of dental implant placed 4 months after the surgical removal of embedded amalgam in the mandibular alveolus using a trephine bur and bone grafting with mineralized freeze-dried bone allograft. Clinical and radiographic evaluations were performed at each appointment to assess factors such as pain, implant mobility, probing depth, and marginal bone loss around the implant. Within 3 years of implant placement, there were no clinical signs and symptoms and no obvious radiographic marginal bone loss. Dental implant installation appears to be safe following the elimination of foreign materials, so long as anatomic and biological factors and appropriate implant choice, are taken into consideration.
PubMed: 38709071
DOI: 10.1097/SCS.0000000000010229 -
Dental Research Journal 2023Similarity in the appearance of a monolithic restoration with the adjacent teeth is necessary. This study aims to influence the foundation material type and ceramic...
BACKGROUND
Similarity in the appearance of a monolithic restoration with the adjacent teeth is necessary. This study aims to influence the foundation material type and ceramic thickness on the final color of zirconia-reinforced lithium silicate (ZLS) ceramic.
MATERIALS AND METHODS
In this experimental study, the A2 translucent blocks of ZLS were sectioned into rectangular specimens with thicknesses 1, 1.5, and 2 mm ( = 15). Substructure materials include resin composite (B1, D2, A2, A3, and C3), nickel chrome alloy, amalgam, and white and black substrate. Substructure material of resin composite with A2 color was proposed as the control group. The value of the color difference (ΔE) is calculated by the CIEDE2000 formula. Data analysis was accomplished by two-factor repeated measures ANOVA and one-sample -test (α =0.05).
RESULTS
The mean value of maximum ΔE with a black substrate (12.13 ± 0.17) at 1 mm ceramic thickness and the mean value of minimum ΔE with B1 resin composite foundation material (0.02 ± 0.17) at 2 mm ceramic thickness are visible. The significant effect of the foundation restoration type, thickness, and interaction between them is visible on ΔE ( < 0.001).
CONCLUSION
Different thickness is required to meet ideal esthetic outcomes with different substrates. Under the conditions of this investigation, zirconia-reinforced lithium silicate over black, white, nickel-chromium, and amalgam did not meet acceptable outcomes.
PubMed: 38020248
DOI: No ID Found -
Operative Dentistry Jan 2024The 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,...
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.
Topics: Temperature; Water; Dental High-Speed Equipment; Composite Resins; Tungsten Compounds; Diamond; Surface Properties
PubMed: 38057997
DOI: 10.2341/23-033-L -
Human & Experimental Toxicology 2024This study examined the impact of mercury (Hg) vapor exposure from amalgams among all American pregnant women. Amalgam-Hg vapor exposure among 1,665,890...
This study examined the impact of mercury (Hg) vapor exposure from amalgams among all American pregnant women. Amalgam-Hg vapor exposure among 1,665,890 weighted-pregnant women ( = 37) was examined in the 2015-2020 National Health and Nutrition Examination Survey (NHANES). Correlation coefficients between amalgam surfaces and daily micrograms (µg) of urinary Hg excretion and daily µg of Hg vapor exposure from amalgams per kilogram (Kg) bodyweight were calculated. Daily Hg vapor exposure from amalgams was compared to Hg vapor safety limits. About 600,000 pregnant women (∼36%) had at least one amalgam surface. Median daily urinary Hg excretion was ∼2.5-fold higher among pregnant women with amalgams as compared to pregnant women without amalgams. A significant correlation was observed between the number of amalgam surfaces and daily urinary Hg excretion. Among pregnant women with amalgams, it was estimated that the median daily Hg vapor dose from amalgams was 7.66 µg of Hg and 0.073 µg of Hg/Kg bodyweight. Among all pregnant women, ∼28% received daily Hg vapor doses from amalgams above the least restrictive United States (US) Environmental Protection Agency (EPA) safety limit and ∼36% received above the most restrictive California (CA) EPA safety limit. Given the potential for fetal toxicological effects from prenatal Hg vapor exposure, special emphasis needs to be placed on reducing/eliminating amalgams in pregnancy/women of reproductive age and future studies should evaluate adverse pregnancy outcomes.
Topics: Humans; Female; Pregnancy; Pregnant Women; Nutrition Surveys; Mercury; Dental Amalgam
PubMed: 38316638
DOI: 10.1177/09603271241231945 -
Materials (Basel, Switzerland) Apr 2024Dental amalgams have been used by dentists for the restoration of posterior human teeth. However, there have been concerns about the release of mercury from amalgams...
Dental amalgams have been used by dentists for the restoration of posterior human teeth. However, there have been concerns about the release of mercury from amalgams into the oral cavity. The objective of the present research is to study the effect of titanium (Ti) nanoparticles on the microstructural mechanism of the release of mercury vapor in two commonly used brands of dental amalgam (the Dispersalloy: 11.8% Cu; the Sybralloy: 33% Cu). Ti powder was added to both the Dispersalloy and the Sybralloy in increments of 10 mg up to 80 mg. The addition of Ti powder to both brands of dental amalgam has been found to result in a considerable decrease in Hg vapor release. The decrease in the Hg vapor release due to Ti addition has been explained by the formation of strong Hg-Ti covalent bonds, which reduce the availability of Hg atoms for evaporation. The Ti atoms in excess of the solubility limit of Ti in Hg reside in the grain boundaries, which also reduces the evaporation of Hg from the amalgam. The binding of Hg with Ti via a strong covalent bond also results in a significant improvement in mechanical properties such as Vickers hardness.
PubMed: 38612175
DOI: 10.3390/ma17071662