Purpose: To compare the flexural properties and the adhesion of Lactobacillus salivarius (LS), Streptococcus mutans (SM), and Candida albicans (CA) on heat-polymerized (CV), CAD-CAM milled (CAD), or ...3D-printed (3D) Poly (methylmethacrylate) (PMMA).Methods: Ultimate Flexural Strength (UFS), Flexural Strain (FS) (%) at Flexural Strength, and Flexural Modulus (FM) of specimens (65.0×10.0×3.3 mm) from each PMMA group (n=6) were calculated by using the 3-point bending test. The surface roughness profiles (R) were measured before and after polishing with a contact profilometer. LS, SM, and CA adhesion on PMMA specimens (n=18) (10 mm in diameter, 3 mm in height) was assessed after 90 minutes and 16 hours by using scanning electron microscopy. The Kruskal-Wallis test with post hoc analysis was performed to compare the groups (alpha=0.05).Results: Mean UFS values were 80.79±7.64 MPa for CV, 110.23±5.03 MPa for CAD, and 87.34±6.39 MPa for 3D. Mean FS values were 4.37±1.04% for CV, 4.71±0.62% for CAD, and 6.19±0.13 % for 3D. Mean FM values were 2542±301 MPa for CV, 3435±346 MPa for CAD, and 2371±197 MPa for 3D. CAD had the lowest average R value (0.29±0.16 µm) before polishing, and bacterial adhesion after 90 minutes of incubation. R value and microbial adhesion were not different amongst groups after polishing and 16 hours of incubation, respectively.Conclusion: The CAD group displayed the best flexural properties, except for FS, the lowest roughness before polishing and bacterial adhesion after 90 minutes of incubation. All tested PMMAs had similar surface roughness after polishing, and microbial adhesion after 16 hours of incubation.
Compare the accuracy of intraoral digital impression in full-arch implant-supported fixed dental prosthesis acquired with eight different intraoral scanner (Ios).
A polymethyl methacrylate acrylic ...model of an edentulous mandible with six scan-abutment was used as a master model and its dimensions measured with a coordinate measuring machine. Eight different Ios were used to generate digital impression: True Definition, Trios, Cerec Omnicam, 3D progress, CS3500, CS3600, Planmeca Emelard and Dental Wings. Fifteen digital impressions were made. A software called “Scan-abut” was developed to analyse and compare the digital impression with the master model, obtaining the scanning accuracy. The three-dimensional (3D) position and distance analysis were performed.
Mean value of the 3D position analysis showed that the True Definition (31 μm ± 8 μm) and Trios (32 μm ± 5 μm) have the best performance of the group. The Cerec Omnicam (71 μm ± 55 μm), CS3600 (61 μm ± 14 μm) have an average performance. The CS3500 (107 μm ± 28 μm) and Planmeca Emelard (101 μm ± 38 μm) present a middle-low performance, while the 3D progress (344 μm ± 121 μm) and Dental Wings (148 μm ± 64 μm) show the low performance. The 3D distance analysis showed a good linear relationship between the errors and scan-abutment distance only with the True Definition and CS3600.
Not all scanners are suitable for digital impression in full-arch implant-supported fixed dental prosthesis and the weight of the output files is independent from the accuracy of the Ios.
Purpose
Reconstructing the occlusal morphology of posterior teeth in definitive dental prosthesis can be challenging. The use of the correlation technique enables replication of the information and ...occlusal anatomy of interim dental prostheses to the definitive ones. The purpose of this controlled clinical trial was to compare the static and dynamic contacts (SDC) of monolithic zirconia crowns designed with correlation and library techniques.
Material and Methods
Twenty‐four patients were included in the study for a total of 28 molars. For each abutment tooth, an interim crown was fabricated and two digital scans, with and without the interim crown in place were made. Two single crowns were designed using correlation and library techniques. Fifty‐six monolithic zirconia crowns were milled. The interim and definitive crowns were evaluated intraorally for SDC by using a 24‐μm‐thick blue articulating foil. After removing the interim and definite crowns, extraoral photographs were taken to calculate the SDC area using software (ImageJ) and analyzed by the Kruskal‐Wallis test.
Results
The average and ± standard deviation (SD) of area of the occlusal marks on interim crowns was 32.27 ± 3.45 mm2. Definitive crowns designed by using the correlation technique had an area of 31.01 ± 3.73 mm2; the area in the library technique was 36.85 ± 5.78 mm2. No statistically significant difference was found (p = 0.091) between the occlusal mark areas of the interim and definitive crowns designed by using the correlation technique. Whereas, there were significant differences between the areas of occlusal marks of the interim and definitive crowns designed by using the library technique, and between the areas of occlusal marks of definitive crowns designed by using the correlation and library techniques (p < 0.001).
Conclusion
The average area of the SDC of monolithic zirconia crowns designed by using the correlation technique was similar to that of interim crowns. The library technique was less effective when replicating the SDC compared to the correlation technique.
Implant site preparation through drilling procedures may cause bone thermonecrosis. The aim of this in vitro study was to evaluate, using a thermal probe, overheating at implant sites during ...osteotomies through 2 different drilling methods (continuous drilling technique versus intermittent drilling technique) using irrigation at different temperatures. Five implant sites 13 mm in length were performed on 16 blocks (fresh bovine ribs), for a total of 80 implant sites. The PT-100 thermal probe was positioned 5 mm from each site. Two physiological refrigerant solutions were used: one at 23.7°C and one at 6.0°C. Four experimental groups were considered: group A (continuous drilling with physiological solution at 23.7°C), group B (intermittent drilling with physiological solution at 23.7°C), group C (continuous drilling with physiological solution at 6.0°C), and group D (intermittent drilling with physiological solution at 6.0°C). The Wilcoxon rank-sum test (2-tailed) was used to compare groups. While there was no difference between group A and group B (W = 86; P = .45), statistically significant differences were observed between experimental groups A and C (W = 0; P =.0001), B and D (W = 45; P =.0005), and C and D (W = 41; P = .003). Implant site preparation did not affect the overheating of the bone. Statistically significant differences were found with the refrigerant solutions. Using both irrigating solutions, bone temperature did not exceed 47°C.
To evaluate patient perception and operating time of digital (DW) and conventional (CW) workflows for the rehabilitation of a screw-retained, single-implant crown.
A convenience sample of 10 patients ...with single implants in posterior sites was recruited for treatment with screw-retained single crowns, fabricated with either a DW or a CW protocol. Operating time and clinical adjusting time were recorded with a stopwatch, and patient preference and self-perception of the esthetic outcome were evaluated with a visual analog scale.
The mean operating time for the DW crowns was 16:21 minutes and for the CW crowns was 28:28 minutes. The mean total adjustment times were 118.1 seconds for the DW protocol and 181.5 seconds for the CW protocol. The mean score regarding self-perception of the esthetic outcome was 73 for DW crowns and 69 for CW crowns; for discomfort, the mean score was 15.5 for DW and 62 for CW.
The DW approach resulted in a time reduction for both the impression phase and operative time.
Background
Dental calculus is the result of dental plaque mineralization, originating from the tooth‐associated bacterial biofilm. Recent evidence revealed that the dental calculus microbiome has a ...more complex composition than previously considered, including an unstructured mix of both aerobes and anaerobes bacteria. Actually, we lack information about the influence of host lifestyle factors, such as diet and health on this highly biodiverse ecosystem. Here, we provide a pilot study investigating dental calculus microbial biodiversity and its relation with the host diet.
Methods
We collected 40 dental calculus samples during routine dental inspection; deoxyribonucleic acid was extracted and analyzed through 16S amplicon sequencing, while dietary information was retrieved through a questionnaire. Associations between diet and oral bacteria taxonomy and functional pathways were statistically tested.
Results
Overall, microbiome composition was dominated by 10 phyla and 39 bacterial genera, which were differently distributed among samples. Cluster analysis revealed four main groups based on the taxonomic profile and two groups based on functional pathways. Each taxonomic cluster was dominated by different microbial biomarkers: Streptococcus, Rothia, Tannerella, Lautropia, and Fusobacterium. Bacteria genera and pathways were also associated with specific dietary elements, especially vegetable and fruit intake suggesting an overall effect of diet on dental calculus microbiome.
Conclusions
The present study demonstrates that there exists an inter‐variability in the microbial composition of dental calculus among individuals of a rather homogeneous population. Furthermore, the observed biodiversity and microbial functions can find an association with specific dietary habits, such as a high‐fiber diet or a protein‐rich diet.
Oral health is fundamental to our well-being, especially in adolescence. The aim of this study is to investigate oral hygiene knowledge through a questionnaire in a sample of adolescents, paying ...particular attention to those wearing orthodontic braces. The study was designed as a descriptive report of a local survey. An anonymous questionnaire was distributed to individuals born between 2000 and 2005, both on paper and online. Among 213 adolescents answering the questionnaire, 206 went to the dentist at least once (most of them between 5 and 9 years old), and 144 experienced at least one session of professional oral hygiene. Approximately 83% of the sample brushed their teeth at least twice a day, while only 7% used dental floss daily. Only 54% of respondents wearing orthodontic braces were advised to undergo professional oral hygiene during their orthodontic treatment. Education on oral hygiene at home came only from their parents for 61% of the whole sample. Most respondents had their first visit to the dentist apparently too late. Flossing was rare, whether the adolescents wore orthodontic braces or not. In many cases, professional oral hygiene was not common during orthodontic treatment. Adolescents did not learn about oral hygiene from a dental specialist.
Accuracy of 3D digital modeling of dental arches Favero, Riccardo; Volpato, Andrea; Francesco, Maurizio De ...
Dental Press Journal of Orthodontics,
01/2019, Volume:
24, Issue:
1
Journal Article
Peer reviewed
Open access
The aim of the study was to verify and compare the accuracy of full-arch digital impressions obtained using two intraoral scanners and three scanning methodologies.
A resin model created with dental ...3-D printing was scanned by a reference scanner (Zfx Evolution - Zimmer Biomet, Palm Beach Gardens, FL) in order to obtain a 3D reference; the same resin model was then scanned with two different intraoral scanners (Zfx IntraScan and Carestream 3600 - CS 3600®, Carestream, Rochester, NY, USA) using: Technique A (from tooth #27 up to tooth #17); Technique B (from tooth #11 up to tooth #17 and then from tooth #21 up to tooth #27) and Technique C (from tooth #22 up to tooth #17, and then from tooth #12 up to tooth #27 - the MeshLab software v. 1.3.3 was then used to match the two scans). The scans obtained were superimposed over the reference scan by means of a software, and the volumetric discrepancies were calculated.
The mean results for the Zfx Intrascan scanner were: Technique A = 302.47 ± 37.42 µm; Technique B = 180.45 ± 29.86 µm; Technique C = 147.34 ± 28.23 µm. The mean results for the Carestream 3600 scanner were: Technique A = 303.59 ± 40.20 µm; Technique B = 181.53 ± 29.61 µm; Technique C = 142.28 ± 35.33 µm. Technique C, used by both scanners, produced less volumetric discrepancies compared to the other techniques.
The scanning technique had a statistically significant effect on the quality of the scan (p< 0.0001), whereas the scanner did not present any significant influence (p= 0.91).
Purpose The aim of the present study was to compare piezoelectric surgery and conventional rotatory osteotomy for mandibular third molar germ extraction to determine the 2 methods' suitability and ...the postoperative outcomes. Patients and Methods Mandibular third molar germectomy was performed bilaterally, randomly choosing 1 side for rotatory osteotomy (rotatory group) and the other for piezoelectric surgery (piezo group). The predictor variable was the duration of the surgical procedure. The outcome variables were the suitability of the method used, bleeding, and the postoperative parameters (ie, mouth opening range, clinical appearance of soft tissues, exudate, abscess, wound dehiscence, locoregional lymphadenopathy, pain on palpation at the extraction site, persistent edema) at 7 and 30 days postoperatively. The patients recorded their subjective postoperative pain daily for 7 days using a visual analog scale. The Wilcoxon rank-sum test and stepwise logistic regression model with binary variables were used for statistical analysis. Results A total of 26 patients (mean age 15.4 ± 1.29 years) were enrolled in the present study. The time needed to complete the osteotomy and extraction was significantly greater for the piezo group (15.77 ± 6.56 minutes) than for the rotatory group (11.77 ± 6.24 minutes; P = .028). No statistically significant differences emerged between the 2 methods for the other outcome variables considered. Conclusions Piezoelectric osteotomy proved comparable to the rotatory method in terms of the surgeon's perception of the suitability of the 2 methods and the related postoperative sequelae. However, piezoelectric osteotomy took longer to complete than the rotatory method.
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