Transitioning from injectable resin composite restorations to resin composite CAD/CAM veneers: A clinical report.

OBJECTIVE: To describe a shift from injectable resin composite technique to composite resin computer-aided design and computer-aided manufacturing (CAD/CAM) veneers in addressing esthetic concerns associated with diastemas between anterior lower teeth in a clinical case. CLINICAL CONSIDERATIONS: Among several techniques proposed for direct resin composite restoration, the "Injectable resin composite technique" has gained popularity for its time-efficiency, reduced technique sensitivity, and diminished reliance on clinician skills. However, challenges such as staining and the need for frequent polishing follow-ups may prompt the consideration of more stable alternatives such as indirect veneer restorations. While ceramic veneers offer superior mechanical and optical properties, resin ceramic veneers, especially those milled from CAD/CAM resin ceramic blocks, offer advantages such as rapid, cost-effective production, simplified intra-oral repairs, less susceptibility to fracture, superior stress absorption, and requires minimal tooth preparation, making them an appealing option for many patients. Moreover, a fully-digital approach not only streamlines the process but also saves time and labor while ensuring the delivery of high-quality restorations to patients. CONCLUSION: In addressing a patient's dissatisfaction with constant polishing of direct resin composite restorations, a shift to resin composite CAD/CAM veneers was implemented. Utilizing a fully-digital approach with CAD/CAM resin ceramic restorations successfully restored both esthetics and function. CLINICAL SIGNIFICANCE: While the injectable resin composite technique achieves immediate esthetic results, its low color stability necessitates frequent polishing sessions. The replacement of direct resin composite restorations with CAD/CAM resin composite veneers becomes a viable option for patients seeking more stable restorations that require fewer follow-ups. This transition addresses both esthetic concerns and the need for enduring solutions in restorative dentistry.

Quo vadis, esthetic dentistry? Part II: Composite resin overtreatment and social media appeal.

OBJECTIVES: This article presents case reports highlighting over-treatments with resin composites, often misconceived as minimally invasive procedures. CLINICAL CONSIDERATIONS: Tooth-colored restorative materials, such as ceramics and composites, have found widespread application to correct problems related to tooth color, shape, and alignment. When composite resin is used, these procedures can be done in a very conservative, cost-effective, and timely fashion. However, it is noteworthy that contemporary dental esthetic expectations are based on standards propagated by social media and other marketing and communications platforms. The abuse of and addiction to social media impacts can lead to unrealistic esthetic expectations and standards for both patients and dentists. CONCLUSIONS: After a critical discussion on ceramic veneers published in part I of this 2-part series, this article directs attention towards what has become a trendy fashion, i.e., the use of direct composite resins as "non-prep" veneers in clinical situations that arguably required no restorative intervention at all. We further explore how social media influences the decision-making processes of both professionals and patients.

Lipase immobilization via cross-linked enzyme aggregates: Problems and prospects - A review.

In this review we have focused on the preparation of cross-linked enzyme aggregates (CLEAs) from lipases, as these are among the most used enzyme in bioprocesses. This immobilization method is considered very attractive due to preparation simplicity, non-use of supports and the possibility of using crude enzyme extracts. CLEAs provide lipase stabilization under extreme temperature or pH conditions or in the presence of organic solvents, in addition to preventing enzyme leaching in aqueous medium. However, it presents some problems in the preparation and limitations in their use. The problems in preparation refer mainly to the crosslinking step, and may be solved using an aminated feeder. The problems in handling have been tackled designing magnetic-CLEAs or trapping the CLEAs in particles with better mechanical properties, the substrate diffusion problems has been reduced by producing more porous-CLEAs, etc. The enzyme co-immobilization using combi-CLEAs is also a new tendency. Therefore, this review explores the CLEAs methodology aimed at lipase immobilization and its applications.

3D-printed resins for provisional dental restorations: Comparison of mechanical and biological properties.

OBJECTIVES: To characterize the mechanical and biological properties of three commercially available resins, which are currently used for provisional restorations and to compare them to an experimental resin intended for definitive fixed dental prostheses. MATERIALS AND METHODS: Three commercially available resins: Crowntec (CT, Saremco), Temporary C&B (FL, Formlabs), C&B MFH (ND, Nextdent), and the experimental resin: Permanent Bridge (PB, Saremco) were printed and subjected to biaxial flexural strength test, finite element analysis, Weibull analysis, scanning electron microscopy, cell proliferation, immunohistochemistry and cytotoxicity assays. Samples from CT, PB, and ND were provided directly from the manufacturers ensuring ideal workflow. FL was printed using the workflow as recommended by the manufacturer, using a Formlabs 2 printer and their post-processing units Form Wash and Form Cure. RESULTS: From the tested resins, PB yielded the best overall results in terms of mechanical properties. Cell proliferation and cytotoxicity did not show any significant differences among materials. PB showed higher values for probability of survival predictions (35%) when subjected to 250 MPa loads, whereas the other materials did not reach 10%. SIGNIFICANCE: Despite mechanical differences between the evaluated materials, the outcomes suggest that 3D printed provisional resins may be used in clinical settings, following the manufacturers indications. New materials intended for long-term use, such as the PB resin, yielded higher mechanical properties compared to the other materials. Alternative printing and post-processing methods have not yet been evaluated and should be avoided until further literature is available. CLINICAL SIGNIFICANCE: 3D printed resins for provisional restorations have become popular with the emergence of new technologies. In this study, we evaluated three different commercially available resins for provisional restorations and one new experimental resin. The results from this study indicate that commercially available resins could be used in clinical settings under certain conditions and limited periods of time. Following the manufacturers protocols is of paramount importance to not compromise these properties.

Comparative study of molar and incisor bite forces regarding deciduous, mixed, and definitive dentition.

Objective: To compare maximum incisor (MBFinc) and molar (MBFmol) bite forces regarding the type of dentition and sex and to establish a relationship between them.Methods: One hundred-five individuals were divided into 3 groups: G1 - 22 females/13 males (4-5 years); G2 - 15 females/20 males (11-12 years); and G3 - 16 females/19 males (17- 18 years). The maximum bite force was recorded with an extraoral measuring device. Three measurements were recorded: right and left molar level (MBFmol) and incisor level (MBFinc). The ratio %MBFinc/MBFmol was determined.Results: MBFmol and MBFinc values increased with age (p < 0.05). MBFmol showed statistically higher values than MBFinc (p < 0.05), when compared within the same group.Conclusion: MBFinc and MBFmol increased with age. For all groups, MBFmol showed higher values than MBFinc, and %MBFinc/MBFmol ratio was 1:2. No differences were found in maximum bite force between sexes.

A comparison of ceramic crown color difference between different shade selection methods: Visual, digital camera, and smartphone.

STATEMENT OF PROBLEM: The light source stability of digital cameras and smartphones is important in shade matching in restorative and prosthetic dentistry to communicate objectively with the dental laboratory. Techniques that standardize the light source of such devices are lacking, and this limitation can lead to color mismatches, difficulties in color communication, and treatment documentation. PURPOSE: The purpose of this clinical study was to compare the magnitude of color difference (ΔE) among 3 shade selection methods during the fabrication of ceramic crowns: visual shade selection with a shade guide, digital shade selection with a digital camera and cross-polarizing filter, and digital shade selection with a smartphone and a light-correcting device. MATERIAL AND METHODS: Forty-five patients in need of ceramic crowns were enrolled, and shade selection was evaluated according to different protocols: visual shade selection (A-D shade guide and IPS Natural Die Material Shade Guide, sent to the dental laboratory technician via a laboratory prescription); digital shade selection with a digital camera (D7000; Nikon Corp) with an 85-mm lens and wireless close-up flash, with and without a cross-polarizing filter (Polar eyes); and digital shade selection with a smartphone and a light-correcting device (iPhone XS attached to Smile Lite MDP, with and without its cross-polarizing filter accessory). Information from the smartphone was imported to an app (IPS e.max Shade Navigation App; Ivoclar AG) that converted the reading to a shade and level of translucency for the ceramic restoration. For all photographs, a gray reference card with known color values was positioned by the mandibular teeth and was used for white balancing of the digital photographs with a software program. All photographs were edited and sent to the dental laboratory: white-balanced with the shade guide; white-balanced with the substrate shade guide; black and white; saturated; and cross-polarized. Ceramic crowns were made with the same lithium disilicate material (IPS e.max CAD; Ivoclar AG) and cemented with the same resin cement (RelyX Ultimate Clicker, A3 shade; 3M). The ΔE values between the crown and the adjacent tooth were determined. The data were analyzed by using a 1-way analysis of variance (ANOVA) and Tukey post hoc tests (α=.05). RESULTS: The mean ΔE between a cemented ceramic crown and the adjacent tooth in the visual shade selection group was 5.32, significantly different than both digital camera (ΔE=2.75; P=.002) and smartphone (ΔE=2.34; P=.001), which were not different from each other (P=.857). CONCLUSIONS: The digital shade selection with photographs acquired with both a digital camera and a smartphone with a light-correcting device showed a threshold within the acceptable values (ΔE<3.7), whereas the visual shade selection showed an average ΔE above the threshold for acceptable values (ΔE>3.7). The use of a gray reference card helped standardize the white balance from the digital images.

Quo vadis, esthetic dentistry? Ceramic veneers and overtreatment-A cautionary tale.

The increased emphasis on orofacial esthetics, experienced both by dental professionals and the lay public, results in an environment where overtreatment can easily occur. Patients on the one hand feel pressure from esthetic norms that are often unrealistic, while dental professionals are compelled to deliver immediate results many times without considering what is best for the ill-informed patient. This article is an illustrated cautionary tale against overtreatment disguised as esthetic dentistry. Representative clinical examples illustrate how porcelain veneers are used without following sound operatory principles, as well as how these cases have been resolved.

Evaluation of trueness and precision of two intraoral scanners and a conventional impression: an in vivo clinical study.

OBJECTIVE: To evaluate, in vivo, trueness and precision of two intraoral scanners, CEREC Omnicam (OMNI) and CEREC Primescan (PRIM), compared to a conventional impression serving as a master model. METHOD AND MATERIALS: Impressions were performed for seven participants. For each participant, conventional polyvinylsiloxane impression and digital impressions using two intraoral scanners, OMNI (software 4.6; CEREC ORTHO Protocol) and PRIM (10 digital impressions per participant, per scanner), were made. Conventional impression was digitized with a laboratory scanner (INEOS X5), and used as reference model. .STL files were superimposed with software (Geomagic Control X) using the tools Initial Alignment and Best Fit Alignment, and trueness and precision were evaluated. Statistical evaluation was performed with Shapiro-Wilk and Mann-Whitney tests (P < .05). RESULTS: Total mean trueness for the OMNI system was 56.45 ± 7.80 µm, and 47.29 ± 5.47 µm for the PRIM system. Regarding precision, values from the OMNI system were 42.47 ± 6.91 µm and from the PRIM system 21.86 ± 4.40 µm. PRIM presented better results for both trueness (P = .000) and precision (P = .000) when compared to OMNI. CONCLUSIONS: PRIM provided a better combination of trueness and precision than its predecessor OMNI. However, both PRIM and OMNI performed acceptably when performing indirect restorations, according to the current acceptable thresholds, considering both trueness and precision. CLINICAL IMPLICATIONS: Full-arch impressions with Primescan presented more precision and trueness than Omnicam; however, compared to previous reported values of conventional impressions, they still presented lower accuracy.

Effect of different fabrication steps on color and translucency of a CAD-CAM feldspathic ceramic.

OBJECTIVE: To evaluate color differences (ΔE) of different fabrication steps performed on a feldspathic ceramic and relative translucency parameter (RTP) after glazing; and to evaluate their effects on the color parameters: L*, a* and b*. MATERIAL AND METHODS: Computer-aided design/computer-aided manufacturing (CAD-CAM) feldspathic maxillary right central incisor ceramic crowns (Cerec Blocs; 1.4 mm thickness) were fabricated through scanning a model preparation and milling. A total of 20 specimens were used and different parameters were compared with each other for color difference (ΔE): original block, milling, polishing, glazing and try-in cements; RTP was measured after glazing. Color parameters (L*, a*, and b*) were evaluated after each step with a spectrophotometer (Vita Easyshade V) and compared using the CIEDE2000 formula. Statistical analyses were done using one-way ANOVA and post-hoc tests. RESULTS: The highest ΔE value was observed for Original versus Milling group (4.73) and the lowest for Polishing versus Glazing (0.49). RTP after glazing presented a value of 12.01. L*, a*, and b* parameters were different among groups. Milling group was the one that presented more differences compared to the Original block regarding L*, a*, and b* parameters. CONCLUSIONS: Different fabrication steps resulted in perceptible color differences within themselves, and L*, a*, and b* parameters changed according to each step. All milling specimens presented unacceptable color differences when compared to the other steps, and milling specimens showed all color parameters (L*, a*, and b*) statistically different compared to the Original block. A high RTP value was observed, demonstrating that, at 1.4 mm thickness, the feldspathic ceramic presented high translucency, showing that opacification of substrate might be necessary. CLINICAL SIGNIFICANCE: Different fabrication steps can greatly affect the optical properties of the feldspathic ceramic restoration studied and cause a relevant impact when compared to the ceramic block itself. Crowns evaluated right after milling presented the highest color differences. In order to obtain optical properties as close as possible to the original feldspathic ceramic block, either polishing or polishing and glazing needs to be performed.

Multidisciplinary clinical approach of an orthodontic treatment and complete digital rehabilitation of laminate veneers for esthetically compromised worn teeth.

AIM: The present clinical case reports on the workflow of a multidisciplinary treatment including both orthodontic and esthetic procedures for the rehabilitation of a young patient with severe wear in the anterior area of both the maxillary and mandibular arches due to malocclusion. The described workflow comprises a digital step-by-step process that involves 3D printing, intraoral scanners, and CAD/CAM milling systems. RESULTS: Accurate diagnostic and treatment planning were paramount when different specialties needed to combine and work together. For that purpose, different digital procedures helped to improve the predictability and the dynamic of the orthodontic and restorative treatments. CONCLUSION: The present multidisciplinary clinical case was executed with a digital approach that assisted to speed things up and achieve a predictable treatment option.

Workflow of digitally guided direct composite resin restorations using ?open source software and 3D printing: a clinical technique.

Objective: To describe how to perform, in a simple manner, a digital wax-up with ?open source software for a clinical application involving direct ?composit?e resin restorations. Report: The clinical technique described presents a simple and highly predictable way of performing direct restorations with the help of a digital wax-up made with ?open source software. ?It uses an open source digital tooth library? to reestablish a more harmonious smile architecture, specifically of teeth that were worn due to parafunction, and restored with direct composite resin restorations.
Conclusions: Thanks to the technology that was used in this case, fast, affordable and accurate results c?ould be obtained. In addition, digital files can be stored, saving material, time, and space, and allowing identical replication of the work either virtually or printed at any time, if needed. (Quintessence Int 2021;52:104-110; doi: 10.3290/j.qi.a45426)

Improvement preclinical and clinical skills for dental preparations using assisted training software.

INTRODUCTION: Digital workflow is currently available for different fields of dentistry. Additionally, to clinical use, digital technology is focused on the education and training of students. The objective of this study was to show the potential benefit of the use of digital CAD / CAM technology and assisted training software in the evaluation and improvement of student skills in preclinical and clinical environments. MATERIALS AND METHODS: 30 models of dental preparations were digitalised and analysed by PrepCheck software, after that was used the PrepCheck Report tool, gathering the results of the analysis in an automatically created report and containing the following parameters: analysis of the conicity, distance between a preparation and the opposing jaw, analysis of the type of preparation, quality of the margin and total occlusal convergence. RESULTS: The use of the PrepCheck Pro 2.1 software makes evident the errors made by the students during the biomechanical preparation, since they generally change the inclination, in order to have less difficulties to comply with the parameters established in the preparations. Regarding the evaluated parameters for anterior and posterior fixed prosthesis) such as: 'Conicity', 'Type of preparation' and 'Distance to the antagonist', the preparations, in their majority, were classified within the tolerance range with of 50-60%, 80-93% and 53-67%, respectively. CONCLUSION: This pilot study demonstrated the benefits of using software and CAD/CAM technology in both preclinical and clinical environments for teaching and learning. Its use on preclinical environments allows the student observe qualitatively and quantitatively a preparation flaws when compared to a master's preparation. Lastly, the ease of visualising errors associated with magnification would allow students to improve their skills.

Microcomputed tomography evaluation of cement film thickness of veneers and crowns made with conventional and 3D printed provisional materials.

OBJECTIVE: To evaluate, through microcomputed tomography (µCT), the cement film thickness of veneers and crowns made with different provisional materials. MATERIAL AND METHODS: A veneer and a crown preparation were performed on a central incisor and a second molar of a dental model, respectively, scanned with an intraoral scanner, and the .stl files were exported to an LCD-based SLA three-dimensional (3D)-Printer. Twenty-four preparations were 3D-printed for each veneer and crown and divided into four groups (n = 6/group): (a) Acrylic resin (Acrílico Marche); (b) Bisacrylic resin (Protemp 4); (c) PMMA computer-aided design and computer-aided manufacturing (CAD-CAM) (Vipiblock); and (d) 3D-printed resin for provisional restorations (Raydent C&B for temporary crown and bridge). Veneers and crowns restorations were performed and cemented with a flowable composite. Each specimen was scanned with a µCT apparatus, files were imported for data analysis, and cement film thickness was quantitatively measured. Data were analyzed by 2-way ANOVA and Tukey post-hoc tests (α = .05). RESULTS: Crowns presented a thicker cementation film than veneers (P < .05).The bisacrylic resin showed the smallest veneer film thickness, similar to the acrylic resin (P = .151), which was not significantly different than the PMMA CAD/CAM material (P = .153). The 3D printed provisional material showed the thicker film, different than all other materials (P < .05). The bisacrylic resin showed a cement film thickness with a high number of voids in its surface. For crowns cementation, the 3D printed provisional material showed the thicker cementation film, different than all other materials (P < .05). CONCLUSIONS: Different provisional materials present different film thicknesses. The 3D printed provisional material showed the highest veneer and crown film thicknesses. Veneers film thicknesses were smaller than crowns for all provisional materials. CLINICAL SIGNIFICANCE: The 3D printed provisional material studied can be satisfactorily used, presenting appropriate adaptation with the tooth preparation, however, it shows the highest cement film thickness for both veneers and crowns cementations when compared with other provisional materials. A better internal fit, or smaller cement film thickness is obtained by CAD/CAM materials, acrylic and bisacrylic resins. Veneer cementation showed a smaller cement film thickness compared with crown cementation for all provisional materials.

Shear bond strength evaluation of metallic brackets bonded to a CAD/CAM PMMA material compared to traditional prosthetic temporary materials: an in vitro study.

INTRODUCTION: Orthodontic treatment for adults is currently increasing, and therefore the need to bond brackets to restorations and temporary crowns. The use of CAD/CAM PMMA provisional restorations for orthodontic purposes have not yet been described, and there is currently insufficient information regarding the strength of bracket adhesion. OBJECTIVE: This study aimed at evaluating the effects of thermocycling (TC) and surface treatment on shear bond strength (SBS) of brackets to different provisional materials. METHODS: Forty specimens were made from each material [PMMA (Telio Lab), bis-acryl (Telio CS C&B), and PMMA CAD/CAM (Telio CAD)], sandpapered, and divided according to surface treatment (pumiced or sandblasted) and TC (half of the samples = 1,000 cycles, 5°C/55°C water baths) (n = 10/group). Stainless-steel brackets were bonded to the specimens (using Transbond XT), and SBS testing was performed. Data were analyzed by three-way ANOVA and LSD post-hoc tests (α = 0.05). Failure types were classified with adhesive remnant index (ARI) scores. RESULTS: SBS values ranged from 1.5 to 14.9 MPa. Sandblasted bis-acryl and sandblasted auto-curing PMMA groups presented similar values (p> 0.05), higher than the CAD/CAM material (p< 0.05), with or without TC. When thermocycled, pumiced bis-acryl showed higher SBS than pumiced acrylic (p= 0.005) and CAD/CAM materials (p= 0.000), with statistical difference (p= 0.009). TC showed negative effect (p< 0.05) for sandblasted bis-acryl and pumiced acrylic groups. ARI predominant score was mostly zero (0) for CAD/CAM, 1 and 2 for bis-acryl, and 1 for acrylic groups. CONCLUSION: In general, bis-acryl material showed the highest SBS values, followed by acrylic and CAD/CAM materials, which showed SBS values lower than an optimum strength for bonding brackets.

Shear bond strength evaluation of metallic brackets bonded to a CAD/CAM PMMA material compared to traditional prosthetic temporary materials: an in vitro study

ABSTRACT Introduction: Orthodontic treatment for adults is currently increasing, and therefore the need to bond brackets to restorations and temporary crowns. The use of CAD/CAM PMMA provisional restorations for orthodontic purposes have not yet been described, and there is currently insufficient information regarding the strength of bracket adhesion. Objective: This study aimed at evaluating the effects of thermocycling (TC) and surface treatment on shear bond strength (SBS) of brackets to different provisional materials. Methods: Forty specimens were made from each material [PMMA (Telio Lab), bis-acryl (Telio CS C&B), and PMMA CAD/CAM (Telio CAD)], sandpapered, and divided according to surface treatment (pumiced or sandblasted) and TC (half of the samples = 1,000 cycles, 5°C/55°C water baths) (n = 10/group). Stainless-steel brackets were bonded to the specimens (using Transbond XT), and SBS testing was performed. Data were analyzed by three-way ANOVA and LSD post-hoc tests (α = 0.05). Failure types were classified with adhesive remnant index (ARI) scores. Results: SBS values ranged from 1.5 to 14.9 MPa. Sandblasted bis-acryl and sandblasted auto-curing PMMA groups presented similar values (p> 0.05), higher than the CAD/CAM material (p< 0.05), with or without TC. When thermocycled, pumiced bis-acryl showed higher SBS than pumiced acrylic (p= 0.005) and CAD/CAM materials (p= 0.000), with statistical difference (p= 0.009). TC showed negative effect (p< 0.05) for sandblasted bis-acryl and pumiced acrylic groups. ARI predominant score was mostly zero (0) for CAD/CAM, 1 and 2 for bis-acryl, and 1 for acrylic groups. Conclusion: In general, bis-acryl material showed the highest SBS values, followed by acrylic and CAD/CAM materials, which showed SBS values lower than an optimum strength for bonding brackets.

RESUMO Introdução: Atualmente, a demanda por tratamento ortodôntico em adultos tem aumentado. Consequentemente, também tem aumentado a necessidade de se colar braquetes em restaurações e coroas provisórias. O uso de restaurações provisórias de PMMA CAD/CAM com finalidade ortodôntica ainda não foi descrito e, até a presente data, não há informação suficiente sobre a resistência da colagem dos braquetes a esse tipo de material. Objetivo: O presente estudo teve como objetivo avaliar os efeitos da termociclagem (TC) e do tratamento de superfície sobre a resistência da colagem ao cisalhamento (RC) de braquetes colados em diferentes materiais provisórios. Métodos: Quarenta espécimes foram confeccionados de cada material: resina acrílica PMMA (Telio Lab), resina bisacrílica (Telio CS C&B), e PMMA CAD/CAM (Telio CAD). Em seguida, foram lixados e divididos de acordo com o tratamento de superfície (polidos ou jateados) e TC (metade da amostra - 1.000 ciclos de imersão em água a 5°C e 55°C) (n = 10/grupo). Braquetes de aço inoxidável foram colados aos espécimes (utilizando Transbond XT) e realizou-se o teste de RC. As informações foram analisadas por meio dos testes ANOVA de três vias e post-hoc LSD (α?#8197;= 0,05). Os tipos de falha foram classificados de acordo com os escores do índice de adesivo remanescente (ARI). Resultados: Os valores de RC variaram de 1,5 a 14,9 MPa. Os grupos de resina bisacrílica jateada e de PMMA autopolimerizável jateado apresentaram valores semelhantes (p> 0,05), superiores ao do material CAD/CAM (p< 0,05) com ou sem TC. Quando submetido à TC, o grupo de resina bisacrílica polida apresentou resistência ao cisalhamento maior do que os grupos de resina acrílica polida (p= 0,005) e do material CAD/CAM (p= 0,000), com diferença estatística (p= 0,009). A TC apresentou efeito negativo (p< 0,05) para os grupos de resina bisacrílica jateada e de resina acrílica polida. O escore ARI = 0 foi predominante para o grupo CAD/CAM; os escores 1 e 2, para o grupo resina bisacrílica; e o escore 1, para o grupo resina acrílica. Conclusão: De forma geral, a resina bisacrílica apresentou os maiores valores de RC, seguida da resina acrílica e do material CAD/CAM, que apresentaram valores de RC inferiores à força recomendada para colagem de braquetes.

In vitro evaluation of surface roughness, color stability, and color masking of provisional restoration materials for veneers and crowns.

AIM: To evaluate surface roughness (SR), color stability (CS), and color masking as assessed through the relative translucency parameter (RTP) of different provisional restoration materials before and after water thermocycling (TC). MATERIALS AND METHODS: Four different provisional materialas were selected: acrylic resin, bis-acryl resin, polymethyl methacrylate (PMMA) CAD/CAM blocks, and 3D-printed provisional resin. Samples of 0.6- and 1.3-mm thickness were obtained, and SR, CS, and RTP were determined before and after the samples were submitted to 6000 cycles of TC. A rugosimeter was used to assess SR. Color was determined on white and black backgrounds before and after TC, and color masking was assessed through RTP. CS was determined using a spectrophotometer with the CIEDE2000 formula, before and after TC. RESULTS: SR values before and after TC ranged from -0.01 to 0.28 for 1.3 mm, and from 0.00 to 0.38 for 0.6 mm, respectively. CS (ΔE00 values) ranged from 0.53 to 4.38 for 1.3 mm, and from 0.70 to 5.66 for 0.6 mm, respectively. The highest value was obtained for 3D-printed resin. Finally, for RTP values, the difference before and after TC ranged from -0.036 to 2.66 for 1.3 mm, and from 0.52 to 2.57 for 0.6 mm, respectively, with the PMMA CAD/CAM block being the material with the lowest values in both cases. CONCLUSION: Values of SR, CS, and RTP varied among different materials and thicknesses. The overall performance of 3D-printed resin was inferior to ?that of the other materials. The PMMA CAD/CAM block obtained the overall best values for the conditions tested.

Comparing the use of static versus dynamic images to evaluate a smile.

STATEMENT OF PROBLEM: Smile analysis, as part of the overall facial analysis, is an important component of diagnosis and treatment planning in the esthetic rehabilitation of a patient. Most studies that refer to smile analysis are based on static images. A more comprehensive evaluation can be made with dynamic video images that can be stopped at the most appropriate frame to ensure the best static images for analysis. PURPOSE: The purpose of this clinical study was to evaluate the posed and dynamic smiles of both sexes, considering the type of smile, prevalence of gingival display, dental display at rest, dentogingival display at posed and spontaneous smile, and lip mobility, through digital image acquisition (photographs and video clips) manipulated by using a software program. MATERIAL AND METHODS: Three photographs and 1 video clip were made for each of the 380 voluntary participants aged between 18 and 32 years by using an iPhone 6 iSight 8 MP camera, Moment lens, and artificial 5500 Kelvin light (IceLight). Digital files were evaluated by using a software program (Keynote), determining each point to be evaluated with posed and spontaneous smiles. RESULTS: With static images, 90% of women and 74% of men had gingival display, with only 35% of women and 21% of men having continuous gingival display. With dynamic analysis, these values increased to 100% of women and 95% of men having gingival display and 62% of men and 81% of women having a continuous gingival display (P<.05). The difference between dentogingival display during posed and spontaneous smiles was clear, with 68% of the participants having 2.25 mm more gingival display. Women tend to show slightly more dental display at rest, posed and spontaneous dentogingival display, as well as lip mobility, than men. CONCLUSIONS: The type of smile changes significantly when posed and spontaneous smiles are compared. Women generally show more gingiva and teeth in all the parameters evaluated than men. Dental treatments should be individually planned according to each patient's smile characteristics.

Volumetric polymerization shrinkage and its comparison to internal adaptation in bulk fill and conventional composites: A µCT and OCT in vitro analysis.

OBJECTIVE: To quantify the volumetric polymerization shrinkage (VPS) of different conventional and bulk fill resin composites, through micro-computed tomography (µCT), and qualitative comparison of gap formation through optical coherence tomography (OCT). METHODS: Box-shaped class I cavities were prepared in 30 third-molars and divided into 5 groups (n=6): G1- Filtek Z100 (Z100); G2- Tetric Evoceram Bulk Fill (TEC); G3- Tetric EvoFlow Bulk fill (TEF); G4- Filtek Bulk fill (FBU); and G5- Filtek Bulk fill Flowable (FBF). All groups were treated with Adper Single Bond Plus adhesive and light cured (Bluephase 20i). Each tooth was scanned three times using a µCT apparatus: after cavity preparation (empty scan); after cavity filling (uncured scan) and after light curing of the restorations (cured scan). The µCT images were imported into a three-dimensional rendering software, and volumetric polymerization shrinkage percentage was calculated (%) for each sample. In the same images, interfacial gaps in the pulpal floor were qualitatively evaluated. After µCT evaluation, the pulpal floor from each tooth was polished until a thin tooth structure was obtained and OCT images were obtained by scanning the pulpal portion. Gap formation was observed and qualitatively compared to the µCT images. RESULTS: VPS means ranged from 2.31 to 3.96% for the studied resin composites. The bulk fill materials, either high viscosity or flowable, were not statistically different from each other (p>0.05). The conventional resin composite Z100 presented statistically higher VPS than both high viscosity bulk fill materials studied (p<0.05), although it was statistically similar to the flowable bulk fill materials studied (p>0.05). Both µCT and OCT methodologies enabled gap formation visualization, and images from both technologies could be associated. Gap formation was mostly observed for G1-Z100, G4-FBU, and G5-FBF. VPS% and pulpal gap formation could not be completely associated with each other for all groups and samples. Voids were observed in most of the resin composite fillings, and most VPS were observed in the occlusal area of the samples. SIGNIFICANCE: Volumetric polymerization shrinkage was material-dependent, although bulk fill materials did not differ from each other. Both µCT and OCT enabled interfacial pulpal gap formation visualization. VPS and gap formation cannot be completely associated with one another.

Comparison of a non-destructive technique using three-dimensional imaging and histoanatomical chemical dissolution for dental morphology analysis.

AIM: The present work aims to compare a digital dental histoanatomical analysis method with chemical enamel dissolution for the study of dental morphology. MATERIAL AND METHODS: Extracted maxillary anterior teeth were scanned under microcomputed tomography (µCT) (µCT 40; Scanco Medical), segmented, and reconstructed three-dimensionally (Amira, version 5.5.2; VSG). Following the digital acquisition of dental morphology, all specimens were acid treated with 5% formic acid for careful dissolution of the enamel layer. Six measurements (three buccopalatal and three mesiodistal) per specimen were performed, both digitally following the µCT scan and physically both before and after enamel dissolution. The obtained measurements were subjected to statistical analysis through concordance coefficient measurements and linear regression. RESULTS: A straight line correlation behavior with no statistically significant difference was found between both methods, with a concordance correlation coefficient of 97%. CONCLUSION: The digital, nondestructive, µCT-layered, three-dimensional reconstruction method presented comparable results to acid-etched enamel dissolution, confirming that both options are reliable for the histoanatomical analysis of enamel and dentin morphologies.

Variability of color matching with different digital photography techniques and a gray reference card.

STATEMENT OF PROBLEM: Color matching in restorative and prosthetic dentistry is important for the success of dental treatments, although communication with the dental laboratory remains subjective, and studies of the performance of objective communication methods are lacking. PURPOSE: The purpose of this study was to evaluate color differences (ΔE) and compare color luminosity (L*) values among different types of digital photography equipment used to document tooth color, with and without a gray reference card, and to determine whether the gray card could be used to standardize color assessment in dental photography. MATERIAL AND METHODS: Sixty photographs were made (n=10) using different equipment: a D7000 digital camera (Nikon Corp) with an 85-mm lens and wireless close-up flash (DC+WCF); close-up flash surrounded by 80 grams per square meter (gsm; specification of paper thickness) white printing paper (DC+WPP); ring flash (DC+RF); close-up flash attached to a dual-point rigid flash bracket (DC+DPRF); cross-polarizing filter attached to a close-up flash (DC+CPF); and iPhone 7 (I7). For all photographs, a gray reference card with known color values was positioned at the patients' mandibular teeth, acting as a parameter for the analysis of white-balanced digital photographs. Each photograph underwent white balance with the reference card and software. ΔE were obtained from each piece of equipment by comparing images with and without white balance (original photo) with software and the smallest ΔE achieved was used as the gold standard for comparisons of luminosity. Values of luminosity were subsequently obtained for the different equipment with and without white balancing the photographs; these values were compared using a general estimating equation with Huber-White standard error (α=.05). RESULTS: The use of a cross-polarizing filter was used as the gold standard for luminosity evaluation, as the smallest ΔE (3.4) among photographs were observed when those with and without white balance were compared. Luminosity results from the cross-polarizing filter method (DC+CPF) were not significantly different from those of the DC+DPRF (P=.73), DC+WPP (P=.106), and DC+WCF (P=.551) groups but were statistically different from DC+RF (P=.028) and I7 groups (P<.001). Use of a gray card was significant when a ring flash (P=.008) or the iPhone (P=.023) were used but not statistically significant for the other groups (P>.05). CONCLUSIONS: The use of a cross-polarizing filter results in more color-standardized photographs, while the ring flash system and the iPhone 7 result in less standardized photographs. The gray reference card had a significant effect when a ring flash system or iPhone 7 was used.