OBJECTIVE: This study aimed to evaluate the feasibility of monolithic zirconia laminate veneers (MZLV) compared to lithium disilicate laminate veneers (LDLV).
METHODS: Sixty resin replicas, each prepared with depths of 0.5 mm, 0.7 mm, and 1 mm, were produced using a 3D printer from acrylic teeth. Laminate veneers of these thicknesses were milled from pre-sintered monolithic zirconia (3rd generation) and lithium disilicate blocks. The intaglio surface of MZLV was treated with air abrasion using 110 μm diameter silica-modified aluminium oxide particles and ceramic primer, while LDLV was etched with etchant gel and treated with the ceramic primer before cementation with resin cement. Vertical marginal discrepancy (VMD) was assessed using a stereomicroscope, and a load-to-failure test was conducted using a universal testing machine. Failure modes were evaluated macroscopically on fractured surfaces. Data were analysed statistically using Two-way ANOVA and Bonferroni correction (α = 0.05).
RESULTS: LDLV samples exhibited significantly larger VMD compared to MZLV samples across all thicknesses, especially in cervical, palatal, and mean data. Within the LDLV group, load-to-fracture values for 0.7 mm and 1.0 mm thicknesses were similar, whereas for 0.5 mm thickness, it was significantly lower. In the MZLV group, load-to-fracture values were lower for 0.7 mm and 1.0 mm thicknesses compared to LDLV, but higher for 0.5 mm thickness.
CONCLUSIONS: Material choice and restoration thickness significantly influence laminate veneer restorations\' success. MZLV generally exhibits superior vertical marginal fit compared to LDLV, with varying load-to-failure values across different thicknesses. Clinical management of debonding in MZLV is simpler compared to restoration fracture in LDLV.
CONCLUSIONS: Considering clinical factors, MZLV may be a preferable option to LDLV for this restoration with the thickness of 0.5 mm.

The objective of the present study was to evaluate the influence of different adhesive strategies regarding shear bond strength (SBS) of provisional resin--based materials bonded to the enamel surface as well as on the enamel surface roughness.
Bovine incisors were randomly divided into six groups (n = 10) according to the adhesive strategy used: BRControl (bis-acrylic resin); Spot-etch+BR (spot-etch + bis-acrylic resin); Spot--etchSB2+BR (spot-etch + adhesive + bis-acrylic resin); Spot-etchZ350Flow+BR (spot-etch + flowable composite resin + bis-acrylic resin); SBU+BR (universal adhesive + bis-acrylic resin); Spot-etchSBMP+Z350 (spot-etch + adhesive + composite resin). The enamel surface roughness was determined by a surface profil-ometer. An SBS test was performed in a universal testing machine, and failure modes were classified under magnification. The SBS data were analyzed by one-way analysis of variance (ANOVA). A paired t test was used for enamel surface roughness intragroup comparisons, and the Friedman one-way repeated meas-ures analysis of variance by ranks was used for differences in enamel surface roughness between groups, with the Tukey post hoc test (a = 0.05).
BRControl had the lowest SBS values (MPa), with a significant difference (P ≤ 0.001) from the other groups. Spot-etch+BR had the highest SBS values but with no significant differences from the other groups in which the spot-etch technique was also used. Adhesive failure mode was predominant for all groups. BRControl had the lowest surface roughness difference, significantly different (P = 0.001) from all the other groups.
Spot-etch and other adhesive strategies could be applied to increase the SBS values of provisional restorations to enamel compared with no surface pretreatment. However, the adhesive strategy may change the enamel surface roughness, revealing the importance of cleaning the tooth surface.

In restorative dentistry, the lack of occlusal space may lead to the mutilation of healthy tissue in order to provide sufficient space for the restorative material. Noprep dentistry can be achieved by placing high-bite restorations, followed by Simple Orthodontic Extrusion (SOE) of other teeth to close the created open bite. This rapid, partial orthodontic treatment is well accepted by patients as it can be easily performed using simple buttons, and it takes only a few weeks to reestablish occlusal contacts. The SOE technique is a further development of the Dahl concept. It has the advantages without the disadvantages. Two applications of this technique are presented in this article: the treatment of the severe wear of anterior teeth with no-prep palatal veneers made of Polymer-infiltrated Ceramic Network (PICN, \'hybrid ceramic\') material and the realization of no-prep zirconia resin-bonded bridges (RBBs) to replace missing lateral incisors. An original 3D-printed resin guide for correctly positioning RBBs and facilitating the removal of excess composite cement is also presented. This work highlights the considerable advantages of multidisciplinary collaboration in the field of minimally invasive dentistry.

OBJECTIVE: To evaluate the fabrication trueness of additively manufactured maxillary definitive casts with various tooth preparations fabricated with different 3-dimensional (3D) printers and print orientations.
METHODS: A maxillary typodont with tooth preparations for a posterior 3-unit fixed partial denture, lateral incisor crown, central incisor and canine veneers, first premolar and second molar inlays, and a first molar crown was digitized with an industrial scanner. This scan file was used to fabricate definitive casts with a digital light processing (DLP) or stereolithography (SLA) 3D printer in different orientations (0-degree, 30-degree, 45-degree, and 90-degree) (n = 7). All casts were digitized with the same scanner, and the deviations within each preparation site were evaluated. Generalized linear model analysis was used for statistical analysis (α = 0.05).
RESULTS: The interaction between the 3D printer and the print orientation affected measured deviations within all preparations (P ≤ 0.001) except for the lateral incisor crown and canine veneer (P ≥ 0.094), which were affected only by the main factors (P < 0.001). DLP-90 mostly led to the highest and DLP-0 mostly resulted in the lowest deviations within posterior tooth preparations (P ≤ 0.014). DLP-30 led to the lowest deviations within the first premolar inlay and DLP-45 led to the lowest deviations within the central incisor veneer preparation (P ≤ 0.045).
CONCLUSIONS: Posterior preparations of tested casts had the highest trueness with DLP-0 or DLP-30, while central incisor veneer preparations had the highest trueness with DLP-45. DLP-90 led to the lowest trueness for most of the tooth preparations.
CONCLUSIONS: Definitive casts with tooth preparations fabricated with the tested DLP 3D printer and the print orientation adjusted on tooth preparation may enable well-fitting restorations. However, 90-degree print orientation should be avoided with this 3D printer, as it led to the lowest fabrication trueness.

OBJECTIVE: To analyse the types of chairside CAD/CAM all-ceramic restorations and the color range of all-ceramic materials used so as to provide reference for the application of clinical chairside all-ceramic restoration and the color selection of all-ceramic materials.
METHODS: IPS e.max CAD prostheses and related data were collected from January 2021 to December 2021 from the Department of Prosthodontics, Shanghai Ninth People\'s Hospital, Shanghai Jiao Tong University School of Medicine. The number and type of restorations and the color of materials were investigated and analyzed by descriptive statistics.
RESULTS: A total of 1 374 restorations were included, of which 624 were crown restorations, accounting for 45.41% of the total restorations. 516 cases were veneer, accounting for 37.55%; 219 were inlays, accounting for 15.94%; fixed bridges were all adhesive bridges, with the least number with only 15 cases, accounting for 1.09%. In terms of the selection of restoration materials, the use rate of low-transparent(LT) ceramic blocks was significantly higher than that of other transparent ceramic blocks. A was the most frequently used ceramic color. The most frequently used porcelain blocks for veneers were LTA2 and LTA1; for inlay were LTA3; for crowns were LTA2 and LTA3. The blocks used in the fixed bridges were all LT, and A3 color was the majority.
CONCLUSIONS: Chairside CAD/CAM all-ceramic prostheses made of IPS e.max CAD materials have been widely used in clinical practice. The types of prostheses include veneer, inset, crown and fixed bridge. The most commonly used IPS e.max CAD blocks are LTA2, LTA3 and LTA1. These findings have certain guiding significance for the clinical restoration decision and the reserve of porcelain blocks in primary hospitals.

暂无摘要。

OBJECTIVE: To evaluate the effect of different adhesives and veneering resins on the shear bond strength (SBS) of polyetheretherketone (PEEK).
METHODS: A total of 138 PEEK specimens were randomly divided into 6 groups according to adhesive material application: Control (C, no application), Adhese Universal (A) (Ivoclar Vivadent, Schaan, Liechtenstein), Gluma Bond Universal (G) (Heraeus Kulzer, South Bend, IN, USA), G-PremioBOND (P) (GC Corporation, Tokyo, Japan), Single Bond Universal (S) (3M, Saint Paul, MN, USA) and visio.link (V) (Bredent, Senden, Germany). Each adhesive group was divided into two subgroups according to the type of veneering material: Estenia direct composite (D) and Gradia Plus indirect composite (IN) (both GC Corporation). After the veneering process, the specimens were aged by thermal cycling. Kruskal-Wallis and Mann-Whitney U tests were used for SBS analysis (P < 0.05).
RESULTS: The highest SBS results were obtained in the VIN group, followed by the VD, PD, GIN, AIN, AD, SIN, SD, PIN, GD, CIN and CD groups, respectively (P = 0.001). There were no significant differences in terms of the type of veneering composite when the same adhesive was applied (P > 0.05), except for Gluma Bond Universal (P = 0.009). All the adhesives tested showed clinically acceptable SBS results.
CONCLUSIONS: Visio.link offered the highest adhesion to PEEK, whereas the tested universal adhesives may be used as an alternative to visio.link in clinical settings. It was determined that changing the veneer type has no statistical difference when the same adhesive material is used.

OBJECTIVE: The aim of this study was to compare the marginal fit of prefabricated occlusal veneers with computer-aided design/computer-aided manufacturing (CAD-CAM)-milled zirconia occlusal veneers in the posterior teeth.
METHODS: Forty extracted human maxillary premolars were divided into two groups of 20 each. Group 1 was prepared to receive prefabricated occlusal veneers, and Group 2 was prepared to receive CAD-CAM-milled zirconia occlusal veneers.
METHODS: Prefabricated samples (Edelweiss) were selected for Group 1, whereas for Group 2, the tooth preparations were scanned, and occlusal veneers were fabricated using Exocad designing software and milling machine. After luting, both the groups were submerged in dye, sectioned, and evaluated for marginal fit and microleakage under a stereomicroscope using the microscope imaging software and its measurement tool.
METHODS: Data collected were subjected to statistical analysis using SPSS 27.0. Intragroup and intergroup comparison was done using the Mann-Whitney U test. The Chi-square test was applied to check the depth of penetration of dye based on percentages.
RESULTS: The marginal gap of zirconia occlusal veneers fabricated with CAD-CAM is higher compared to that of prefabricated occlusal veneers. Similarly, the depth of penetration of dye is higher in CAD-CAM-milled zirconia occlusal veneers than prefabricated occlusal veneers.
CONCLUSIONS: The marginal fit of prefabricated occlusal veneer is better than the marginal fit of zirconia occlusal veneers fabricated with CAD-CAM. Similarly, it can also be concluded that the microleakage of prefabricated occlusal veneer is less compared to the CAD-CAM-milled zirconia occlusal veneers.

OBJECTIVE: The aim of the study is measuring the magnitude and determining the method of finger pressure exerted by doctors on ceramic veneers during their fixation.
METHODS: A simulation model was designed in order to measure the volume of finger pressure. Veneers were produced for 2 central incisors. Doctors alternately placed veneers on the model and applied pressure on them for 20 seconds simulating the clinical stage of cementing. The operator recorded the maximum readings of the scales and entered the result on the research protocol. In addition, it was recorded which finger the doctor exerts on the veneer during its cementing to ensure a tight fit: thumb or index finger.
RESULTS: The values obtained during cementation of 54% doctors ranged up to 1 kg, 27% of doctors from 1 to 2 kg and only 19% more than 2 kg. 80% of doctors applied the main pressure on the veneer using their thumb, while the pressure force was 1.4 kg. For those doctors who pressed the veneer to the tooth with their index finger, the impact value was 0.8 kg.
CONCLUSIONS: The finger pressure on the veneer during cementation applied by dentists varies, the average pressure on the veneers was about 1.5 kg. The amount of pressure on cement during laboratory tests of cements for fixing veneers differs from clinical values many times. The development of a veneers fixation protocol, taking into account the conducted research, will ensure a reliable and accurate fit of the veneer at the stage of its cementing.
UNASSIGNED: Измерение величины и определение способа пальцевого давления, оказываемого врачами на керамические виниры во время их фиксации.
UNASSIGNED: Для измерения величины пальцевого давления была спроектирована симуляционная модель. На 2 центральных резца были изготовлены виниры. Врачи поочередно устанавливали виниры на модель и в течение 20 с на них оказывали давление, имитируя клинический этап цементирования. Оператор регистрировал максимальные показания весов и заносил полученный результат в протокол исследования. Кроме того, фиксировали, каким именно пальцем врач оказывает воздействие на винир во время его цементирования для обеспечения плотной посадки: большим или указательным.
UNASSIGNED: Установлено, что 54% врачей во время цементирования оказывают давление на винир до 1 кг, 27% врачей — от 1 до 2 кг, и только 19% врачей — более 2 кг; 80% врачей оказывали основное давление на винир, используя большой палец, при этом сила прижимного давления составила 1,4 кг. У врачей, которые прижимали винир к зубу указательным пальцем, величина воздействия была 0,8 кг.
UNASSIGNED: Пальцевое давление на винир во время его цементирования у разных врачей имеет существенные различия, в среднем давление на виниры составило около 1,5 кг. Давление на цемент во время лабораторных испытаний цементов для фиксации виниров отличается от клинических величин многократно. Разработка протокола фиксации виниров с учетом поведенных исследований обеспечит надежную и точную посадку винира на этапе его цементирования.

BACKGROUND: Commercially available resin cements consist of various filler sizes, filler content and monomers, and it is unclear which of these factors have the greatest effect on the color stability of laminate veneers.
OBJECTIVE: To evaluate the color stability of lithium disilicate-reinforced laminate veneers inserted with three commercial resin cements with various filler sizes/contents and monomers upon accelerated aging.
METHODS: Veneers were fabricated and cemented on resin abutments using three commercially available resin cements comprised of two different monomers and varying filler sizes/contents: 1) triethylene glycol dimethacrylate, TEGDMA (RelyX™ Veneer = 0.6 µm/66 %, Calibra® Esthetic Light Cure =1.2 µm/65 %); and 2) urethane dimethacrylate, UDMA (Variolink Esthetic LC = 0.1 µm/38 %). A total of 60 specimens were fabricated (n = 20 for each cement). The relative number of particles (N) and relative surface area (A) were calculated for each filler size/content. Color coordinates (L*, a*, b*) were measured, and color change (ΔE00) was calculated after cementation and following aging at 150, 300, 450, and 600 h using xenon light. Differences in color coordinates and color change were determined using repeated measures ANOVA followed by Tukey\'s post hoc test (α = .05). A post-hoc power analysis was performed to confirm reliability of the results.
RESULTS: Based on a post-hoc power analysis of a repeated measures ANOVA with two between-factors and 1 within-factor, we had 89 % power to detect a difference of effect by cement type, 10 % power to detect a difference by shade, and 100 % power to detect a difference of effect by aging. The UDMA-based cement (0.1 µm/38 %) was least affected by aging, despite having the largest number of particles (N = 1010) and largest particle surface area (A = 7.02). The TEGDMA-based cements exhibited a significant color change, with 0.6 µm/66 % (A = 2.03, N = 8.12) producing a larger ΔE00 than 1.2 µm/65 % (A = 1.00, N = 1.00).
CONCLUSIONS: Among the commercial cements tested, UDMA-based resin (0.1 µm/38 %) provided better color stability than TEGDMA-based resin cements. The color change after aging was affected by the relative surface area and relative number of particles for the TEGDMA-based resin cement (0.6 µm/66 % and 1.2 µm/65 %), with a larger surface area and a higher relative number of particles, accelerated color change with aging. The present study demonstrates a novel approach to determine color stability for any resin cement with particulate filler.
CONCLUSIONS: The dental practitioner should be selective in choosing a commercial light cure cementation product for laminate veneers, as UDMA containing resin cement is more resistant to color changes over time than TEGDMA, regardless of the filler size/content.