Since its emergence in December 2019, corona virus disease 2019 (COVID-19) has impacted several countries, affecting more than 90 thousand patients and making it a global public threat. The routes of transmission are direct contact, and droplet and possible aerosol transmissions. Due to the unique nature of dentistry, most dental procedures generate significant amounts of droplets and aerosols, posing potential risks of infection transmission. Understanding the significance of aerosol transmission and its implications in dentistry can facilitate the identification and correction of negligence in daily dental practice. In addition to the standard precautions, some special precautions that should be implemented during an outbreak have been raised in this review.
Aerosols ; Betacoronavirus ; Coronavirus Infections ; prevention & control ; transmission ; Cross Infection ; prevention & control ; Dentistry ; Hand Hygiene ; Humans ; Infection Control ; methods ; Pandemics ; prevention & control ; Personal Protective Equipment ; Pneumonia, Viral ; prevention & control ; transmission

In patients with fully edentulous jaw, treatment of complete dentures should be carried out in many stages when following the conventional methods. Therefore there were disadvantages such as multiple visits to dental clinic is inevitable. In addition, errors caused by polymerization shrinkage, which happens during the fabrication of denture, and difficulties in reproduction of damaged or lost denture were considered as disadvantages. But nowadays, computer-aided design and computer-aided manufacturing (CAD/CAM) system is widely used in dentistry and it has begun to expand its spectrum in manufacturing complete dentures. Using CAD/CAM system to fabricate complete dentures can reduce the number of patient's visit and clinical chair time, since taking impression, recording jaw relation, and selection of artificial teeth are performed at the same time during the first visit, and delivering of dentures during the second visit is possible. In addition, because 3D-Printing technology is used, errors by polymerization shrinkage can be reduced. Among the companies that fabricate complete dentures using CAD/CAM system, DENTCA CAD/CAM denture (DENTCA Inc., Los Angeles, CA, USA) is the most commercialized company. In this case, we treated patients of complete dentures using conventional complete denture method and DENTCA CAD/CAM denture system in the same patient. We would like to report this case because we have achieved good results not only in functional aspects of pronunciation, chewing, and swallowing but also in aesthetic aspects.
Computer-Aided Design ; Deglutition ; Dental Clinics ; Dentistry ; Denture, Complete ; Dentures ; Humans ; Jaw ; Jaw, Edentulous ; Mastication ; Methods ; Polymerization ; Polymers ; Reproduction ; Tooth, Artificial

PURPOSE: This study was to evaluate the wear resistance of 3D printed, milled, and conventionally cured provisional resin materials. MATERIALS AND METHODS: Four types of resin materials made with different methods were examined: Stereolithography apparatus (SLA) 3D printed resin (S3P), digital light processing (DLP) 3D printed resin (D3P), milled resin (MIL), conventionally self-cured resin (CON). In the 3D printed resin specimens, the build orientation and layer thickness were set to 0° and 100 µm, respectively. The specimens were tested in a 2-axis chewing simulator with the steatite as the antagonist under thermocycling condition (5 kg, 30,000 cycles, 0.8 Hz, 5℃/55℃). Wear losses of the specimens were calculated using CAD software and scanning electron microscope (SEM) was used to investigate wear surface of the specimens. Statistical significance was determined using One-way ANOVA and Dunnett T3 analysis (α = .05). RESULTS: Wear losses of the S3P, D3P, and MIL groups significantly smaller than those of the CON group (P < .05). There was no significant difference among S3P, D3P, and MIL group (P > .05). In the SEM observations, in the S3P and D3P groups, vertical cracks were observed in the sliding direction of the antagonist. In the MIL group, there was an overall uniform wear surface, whereas in the CON group, a distinct wear track and numerous bubbles were observed. CONCLUSION: Within the limits of this study, provisional resin materials made with 3D printing show adequate wear resistance for applications in dentistry.
Clothing ; Dentistry ; In Vitro Techniques ; Mastication ; Methods ; Printing, Three-Dimensional

PURPOSE: This clinical pilot study was performed to determine the effectiveness of dual-energy cone-beam computed tomography (DE-CBCT) in measuring bone mineral density (BMD).MATERIALS AND METHODS: The BMD values obtained using DE-CBCT were compared to those obtained using calibrated multislice computed tomography (MSCT). After BMD calibration with specially designed phantoms, both DE-CBCT and MSCT scanning were performed in 15 adult dental patients. Three-dimensional (3D) Digital Imaging and Communications in Medicine data were imported into a dental software program, and the defined regions of interest (ROIs) on the 3-dimensional surface-rendered images were identified. The automatically-measured BMD values of the ROIs (g/cm³), the differences in the measured BMD values of the matched ROIs obtained by DE-CBCT and MSCT 3D images, and the correlation between the BMD values obtained by the 2 devices were statistically analyzed.RESULTS: The mean BMD values of the ROIs for the 15 patients as assessed using DE-CBCT and MSCT were 1.09±0.07 g/cm³ and 1.13±0.08 g/cm³, respectively. The mean of the differences between the BMD values of the matched ROIs as assessed using DE-CBCT and calibrated MSCT images was 0.04±0.02 g/cm³. The Pearson correlation coefficient between the BMD values of DE-CBCT and MSCT images was 0.982 (r=0.982, P<0.001).CONCLUSION: The newly developed DE-CBCT technique could be used to measure jaw BMD in dentistry and may soon replace MSCT, which is expensive and requires special facilities.
Adult ; Bone Density ; Calibration ; Cone-Beam Computed Tomography ; Dentistry ; Humans ; Jaw ; Methods ; Miners ; Multidetector Computed Tomography ; Pilot Projects

BACKGROUND: Recently, three-dimensional (3D) printing has been hailed as a disruptive technology in dentistry. Among 3D printers, a digital light processing (DLP) 3D printer has certain advantages, such as high precision and relatively low cost. Therefore, the latest trend in resin crown manufacturing is the use of DLP 3D printers. However, studies on the internal fitness of such resin crowns are insufficient. The recently introduced 3D evaluation method makes it possible to visually evaluate the error of the desired area. The purpose of this study is to evaluate the internal fitness of resin crowns fabricated a by DLP 3D printer using the 3D evaluation method.METHODS: The working model was chosen as the maxillary molar implant model. A total of 20 resin crowns were manufactured by dividing these into two groups. One group was manufactured by subtractive manufacturing system (PMMA), while the other group was manufactured by additive manufacturing system, which uses a DLP 3D printer. Resin crowns data were measured using a 3D evaluation program. Internal fitness was calculated by root mean square (RMS). The RMS was calculated using the Geomagic Verify software, and the mean and standard deviation (SD) were measured. For statistical analysis, IBM SPSS Statistics for Windows ver. 22.0 (IBM Corp., USA) was used. Then, independent t-test was performed between the two groups.RESULTS: The mean±SD of the RMS were 41.51±1.51 and 43.09±2.32 for PMMA and DLP, respectively. There was no statistically significant difference between PMMA and DLP.CONCLUSION: Evaluation of internal fitness of the resin crown made using a DLP 3D printer and subtractive manufacturing system showed no statistically significant differences, and clinically acceptable results were obtained.
Crowns ; Dentistry ; Imaging, Three-Dimensional ; Methods ; Molar ; Polymethyl Methacrylate ; Printing, Three-Dimensional

Tooth enamel is a complex mineralized tissue consisting of long and parallel apatite crystals configured into decussating enamel rods. In recent years, multiple approaches have been introduced to generate or regenerate this highly attractive biomaterial characterized by great mechanical strength paired with relative resilience and tissue compatibility. In the present review, we discuss five pathways toward enamel tissue engineering, (i) enamel synthesis using physico-chemical means, (ii) protein matrix-guided enamel crystal growth, (iii) enamel surface remineralization, (iv) cell-based enamel engineering, and (v) biological enamel regeneration based on de novo induction of tooth morphogenesis. So far, physical synthesis approaches using extreme environmental conditions such as pH, heat and pressure have resulted in the formation of enamel-like crystal assemblies. Biochemical methods relying on enamel proteins as templating matrices have aided the growth of elongated calcium phosphate crystals. To illustrate the validity of this biochemical approach we have successfully grown enamel-like apatite crystals organized into decussating enamel rods using an organic enamel protein matrix. Other studies reviewed here have employed amelogenin-derived peptides or self-assembling dendrimers to re-mineralize mineral-depleted white lesions on tooth surfaces. So far, cell-based enamel tissue engineering has been hampered by the limitations of presently existing ameloblast cell lines. Going forward, these limitations may be overcome by new cell culture technologies. Finally, whole-tooth regeneration through reactivation of the signaling pathways triggered during natural enamel development represents a biological avenue toward faithful enamel regeneration. In the present review we have summarized the state of the art in enamel tissue engineering and provided novel insights into future opportunities to regenerate this arguably most fascinating of all dental tissues.
Acid Etching, Dental ; Amelogenin ; Biomimetics ; trends ; Dental Enamel ; metabolism ; Dental Enamel Proteins ; Dentistry ; trends ; Tissue Engineering ; methods ; Tooth Remineralization

OBJECTIVES: This study aimed to measure the efficacy of different tooth-brushing methods for removing plaque in Korea. METHODS: This study was conducted with the approval of the Institutional Review Board (IRB) of the Seoul National University School of Dentistry (S-D20180021). Thirty participants aged between 19 and 30 years, who did not have periodontal disease, were enrolled in this observational study. Participants were given the same type of toothbrush and toothpaste and asked to brush their teeth as they usually would. During brushing, participants were recorded with a camcorder that was attached to a mirror. Participants were aware they were being recorded. After they had finished brushing their teeth, a dental plaque staining and oral plaque index (PI) examination was performed. The PI score was measured using the Turesky modified Quigley Hein Index. Brushing methods were classified as rolling, horizontal, vertical, circling, and oblique. Skipped surfaces were recorded separately. Following this, statistical analysis was performed using SPSS software. RESULTS: Most surfaces of the mouth were skipped. The most commonly used brushing method was the circling method, followed by the vertical, horizontal, rolling, and oblique methods. The most frequently used method on the vestibular surface was circling, with 52.92% of the oral surface skipped. The oblique brushing method had the lowest mean PI score with a mean±SD of 1.73±0.82. The mean PI score of the skipped surfaces was the highest with a mean±SD of 2.52±0.81. We also analyzed the linear mixed model considering the different lengths of time spent brushing. Both the brushing method used and the time spent brushing had a significant effect on the PI score, but no interactions between these were observed. In areas where a horizontal brushing method had been used, the PI score was significantly decreased. CONCLUSIONS: This study suggests that the horizontal brushing method is an efficient tooth-brushing method compared to the other methods. Additionally, tooth-brushing for more than 10 seconds on 3 to 4 teeth area was effective in removing dental biofilm.
Biofilms ; Dental Plaque Index ; Dental Plaque ; Dentistry ; Ethics Committees, Research ; Humans ; Korea ; Methods ; Mouth ; Observational Study ; Oral Hygiene ; Periodontal Diseases ; Seoul ; Tooth ; Toothpastes ; Video Recording

With development of digital dentistry, the 3-dimensional (3D) manufacturing industry using computer-aided design and computer-aided manufacturing (CAD/CAM) has grown dramatically in recent years. Denture fabrication using digital method is also increasing due to the recent development of digital technology in dentistry. The 3D manufacturing process can be categorized into 2 types: subtractive manufacturing (SM) and additive manufacturing (AM). SM, such as milling is based on cutting away from a solid block of materal. AM, such as 3D printing, is based on adding the material layer by layer. AM enables the fabrication of complex structures that are difficult to mill. In this case, additive manufacturing method was applied to the fabrication of the resin-based complete denture to a 80 year-old patient. During the follow-up periods, the denture using digital method has provided satisfactory results esthetically and functionally.
Computer-Aided Design ; Dentistry ; Denture, Complete ; Dentures ; Follow-Up Studies ; Humans ; Methods ; Printing, Three-Dimensional

BACKGROUND: An inability to cope with threatening dental stimuli, i.e., sight, sound, and sensation of airotor, manifests as anxiety and behavioral management problems. Behavior modification techniques involving pre-exposure to dental equipment will give children a first-hand experience of their use, sounds, and clinical effects. The aim of this study was to compare the techniques of Tell-Show-Play-doh, a smartphone dentist game, and a conventional Tell-Show-Do method in the behavior modification of anxious children in the dental operatory. METHODS: Sixty children in the age group of 4-8 years, with Frankl's behavior rating score of 2 or 3, requiring Class I and II cavity restorations were divided into three groups. The groups were Group 1: Tell-Show-Play-doh; Group 2: smartphone dentist game; and Group 3: Tell-Show-Do technique and each group comprised of 20 children. Pulse rate, Facial Image Scale (FIS), Frankl's behavior rating scale, and FLACC (Face, Leg, Activity, Cry, Consolability) behavior scales were used to quantify anxious behavior. Operator compliance was recorded through a validated questionnaire. RESULTS: The results showed lower mean pulse rates, lower FIS and FLACC scores, higher percentage of children with Frankl's behavior rating score of 4, and better operator compliance in both the Tell-Show-Play-doh and smartphone dentist game groups than in the conventional Tell-Show-Do group. CONCLUSION: The Tell-Show-Play-doh and smartphone dentist game techniques are effective tools to reduce dental anxiety in pediatric patients.
Anxiety ; Behavior Rating Scale ; Behavior Therapy ; Child ; Compliance ; Dental Anxiety ; Dental Equipment ; Dentists ; Heart Rate ; Humans ; Leg ; Methods ; Pediatric Dentistry ; Sensation ; Smartphone ; Weights and Measures

PURPOSE: It has been proposed that using new prediction methods, such as neural networks based on dental data, could improve age estimation. This study aimed to assess the possibility of exploiting neural networks for estimating age by means of the pulp-to-tooth ratio in canines as a non-destructive, non-expensive, and accurate method. In addition, the predictive performance of neural networks was compared with that of a linear regression model. MATERIALS AND METHODS: Three hundred subjects whose age ranged from 14 to 60 years and were well distributed among various age groups were included in the study. Two statistical software programs, SPSS 21 (IBM Corp., Armonk, NY, USA) and R, were used for statistical analyses. RESULTS: The results indicated that the neural network model generally performed better than the regression model for estimation of age with pulp-to-tooth ratio data. The prediction errors of the developed neural network model were acceptable, with a root mean square error (RMSE) of 4.40 years and a mean absolute error (MAE) of 4.12 years for the unseen dataset. The prediction errors of the regression model were higher than those of the neural network, with an RMSE of 10.26 years and a MAE of 8.17 years for the test dataset. CONCLUSION: The neural network method showed relatively acceptable performance, with an MAE of 4.12 years. The application of neural networks creates new opportunities to obtain more accurate estimations of age in forensic research.
Cone-Beam Computed Tomography ; Dataset ; Forensic Dentistry ; Humans ; Linear Models ; Methods ; Neural Networks (Computer)