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Purpose: To evaluate the preferences of dental practitioners for tooth-supported crowns dental ceramics by means of an online survey and to assess the influence of age, gender, years of experience, and dental specialty on those preferences. Materials and Methods: An anonymous questionnaire was delivered online through Google Surveys, targeting 796 dentists. It contained 17 dichotomous, closed questions with two sections. The first section dealt with general characteristics, including age, gender, years of experience, training in prosthodontics, and hours worked per week. The second section included questions regarding preferences of different materials for crowns, and the use of digital workflows. Analyses were carried out with Stata 14.0 software (StataCorp, TX, USA). A significance level of p=0.05 was adopted. Results: 248 surveys were answered. Practitioners in Chile preferred lithium disilicate for the anterior region (55.2%) but also for the posterior area (40.7%), regardless of their age, gender, years since graduation, hours worked per week or any training in prosthodontics. Chilean dentists over 50 years old considered zirconia almost 4 times more than those under 30 years old for anterior crowns (51.85%). 59.68% of dentists take digital impressions, and 37.10% have access to chairside CAD/CAM technology. In this group, 54.4% preferred feldspathic ceramic for anterior and 23.9% for posterior crowns. Conclusions: While there is a wide range of dental ceramic materials, these results provide a snapshot of the current trends in Chile where lithium disilicate is the most preferred ceramic material for tooth-supported crowns, and metal-ceramic is the least preferred material.

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The clinical success of indirect restorations is directly correlated with their specific anatomic shape and design as well as marginal accuracy and overall precision of fit. These factors require a precise impression of the preparation and, to the extent necessary and possible, other teeth and supporting hard and soft tissues.

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OBJECTIVE: This clinical case describes a completely digital workflow using current digital technologies for a full-mouth adhesive rehabilitation with ultra-translucent multilayer zirconia restorations. CLINICAL CONSIDERATIONS: A healthy 60-year-old man with abfractions on all upper and lower molars and severe tooth wear underwent a full-mouth rehabilitation with laminate veneers and partial adhesive restorations. A proper zirconia bonding protocol was realized to provide a durable bond between the ultra-translucent zirconia and the resin cement. Furthermore, the implementation of a digital workflow enables the clinician to have an effective communication during treatment planning and simplify the clinical and laboratory procedures, providing the patient with long-term esthetic treatment and functional results. CONCLUSION: The implementation of a completely digital workflow and the use of ultra-translucent multilayer zirconia for indirect adhesive restorations can be an alternative with simplified and predictable procedures for patients with dental wear and teeth discolorations. CLINICAL SIGNIFICANCE: The digital workflow described is intended to facilitate the planning and execution of a full-mouth adhesive rehabilitation and demonstrates to clinicians a reliable zirconia bonding concept for minimally invasive anterior and posterior restorations.

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PURPOSE: The efficacy of etch-and-rinse, selective enamel-etching, and self-etching protocols for universal adhesives in follow-ups of over 12 months was compared in a network meta-analysis. STUDY SELECTION: Randomized controlled trials (RCTs) published from 1998 to 2022 that compared marginal staining, marginal adaptation, retention and fractures, post-operative sensitivity, or recurrence of caries that took place over 12-months post-restoration were selected. A network meta-analysis determined the performance of each adhesive protocol. RESULTS: After screening 981 articles, 16 RCTs were subjected to data extraction. Of which, 674 patients with 2816 restorations, were included in the network meta-analysis. The pooled risk of marginal discoloration following self-etching was significantly higher than that following etch-and-rinse at over 12, 24, and 36 months, which was time-dependent. The pooled risks of unfavorable marginal adaptation and unfavorable retention and fractures following self-etching were also significantly higher than that following etch-and-rinse, with the rates of unfavorable retention and fractures in non-carious cervical lesions increasing in a time-dependent manner. The pooled risks of marginal discoloration, unfavorable marginal adaptation, retention and fractures were similar between etch-and-rinse and selective enamel-etching protocols. Post-operative hypersensitivity and recurrence of caries were not significantly different among etch-and-rinse, selective enamel-etching, and self-etching protocols. CONCLUSIONS: In follow-ups over 12 months, esthetic and functional outcomes of restorations completed with an etch-and-rinse adhesive protocol were superior to the ones achieved with a self-etching strategy without selective enamel-etching. Selective enamel etching is recommended for self-etching systems. Biological responses were similar for all three adhesive strategies.

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PURPOSE: This in vitro study evaluated the dimensional accuracy of three 3D printers and one milling machine with their respective polymeric materials using a simplified geometrical model. MATERIALS AND METHODS: A simplified computer-aided design (CAD) model was created. The test samples were fabricated with three 3D printers: a dental desktop stereolithography (SLA) printer, an industrial SLA printer, and an industrial fused deposition modeling (FDM) printer, as well as a 5-axis milling machine. One polymer material was used per industrial printer and milling machine while two materials were used with the dental printer for a total of five study groups. Test specimens were then digitized using a laboratory scanner. The virtual outer caliper method was used to measure the linear dimensions of the digitized 3D printed and milled specimens in x-, y-, and z-axes, and compare them to the known values of the CAD model. Data were analyzed with Kruskal-Wallis one-way ANOVA on Ranks followed by the Tukey's test. RESULTS: Milled specimens were not significantly different from the CAD model in any dimension (p > 0.05). All 3D printed specimens were significantly different from the CAD model in all dimensions (p = 0.01), except the dental SLA 3D printer with one of the polymers tested (Bis-GMA) which was not significantly different in two (x and z) dimensions (p = 0.4 and p = 0.12). CONCLUSIONS: The milling technology tested provided greater dimensional accuracy than the selected 3D printing. Printer, printing technology, and material selection affected the accuracy of the printed model.

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OBJECTIVES: This study aimed to provide information on the accuracy of exported digital files with the different resolutions available in the CEREC 4.6.2 software obtained by means of an intraoral scanner (IOS), in addition to establishing differences between materialized models with different exported resolutions, and how these different exported files can influence finite element analysis (FEA) simulations. MATERIALS AND METHODS: The upper complete arch of 10 patients was scanned through an IOS (CEREC Omnicam 1.0/Dentsply Sirona). Files of three resolution meshes digitalized by a CAD software (Cerec SW, 4.6.2) high, medium and low (IOSH, IOSM, and IOSL) were exported. Each file was evaluated by a software (NETFABB) about the number of triangles obtained and compared with the number announced by the manufacturer. Also, with a superimposition with a specialized software (GEOMAGIC X), the digital models were compared. The files of each resolution were printed (Sprintray 3D Printer), and the printed models were scanned with IOS (Omnicam 1.0) and compared with the control group (intraoral scanned high-resolution file, IOSH). FEA simulations were imported into COMSOL and analyzed under different loading conditions. RESULTS: The number of exported triangles coincided with that reported by the manufacturer. The digital models from files of different resolution did not show significant differences (less than 1.5 um) between each other. Models printed (H, M, L) from files of the same resolution mesh (H, M, L) did not show significant differences between them either in partial measures of the arch and neither in the complete arch. FEA showed significant differences in stress concentration between different exported models. CLINICAL SIGNIFICANCE: Digital models can be exported and printed in three resolutions of the mesh, without differences clinically significative. On the other hand, for future FEA applications further research should be performed in order to determine the optimal number of triangles.

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This technique article describes the duplication of a definitive implant-supported computer-aided design and computer-aided manufacture (CAD-CAM) crown with soft-tissue modification on a misplaced implant. Gingival contours were ideally shaped in the stone die, and a custom healing abutment was designed. After scanning the modified surface, images were correlated with the initial intraoral digital scan, and the definitive restoration was designed, milled, and delivered with an ideal soft-tissue emergence profile.

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This study evaluates the shear bond strength (SBS) of various resin cements to different ceramics. Composite resin cylinders of Z100 were fabricated and cemented to disks of feldspathic ceramic (Creation), leucite-reinforced feldspathic ceramic (Empress I), and densely sintered aluminum oxide ceramic (Procera AllCeram) using five resin cements: Panavia F (PAN), RelyX ARC (ARC), RelyX Unicem (RXU), RelyX Veneer, and Variolink II. SBS was measured after three days of water storage (baseline) and after artificial aging (180 days of water storage along with 12,000 thermal cycles). Failure mode of fractured specimens also was evaluated. Data were analyzed with Kruskal-Wallis and Mann-Whitney tests (α=0.05). RXU showed 1) the lowest baseline median SBS to feldspathic ceramic, which was not statistically different from PAN; 2) the lowest median baseline SBS to leucite-reinforced feldspathic and densely sintered aluminum-oxide ceramics. All cements performed similarly after aging, except for ARC (median 0.0 MPa) and PAN (median 16.2 MPa) in the densely sintered aluminum-oxide ceramic group. Resin cements perform differently when bonded to different ceramic substrates. While all test resin cements worked similarly in the long-term to feldspathic and leucite-reinforced feldspathic ceramics, only the MDP-containing resin cement provided durable bonds to densely sintered aluminum-oxide ceramic.

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PURPOSE: To evaluate the survival rate in restored teeth with three different types of retainers prior to the fixing of crowns with zirconia through this retrospective clinical study. It is unclear how the type of post and core rehabilitation, and type of resin cement affect the longevity of teeth restored with crowns. METHODS: In a private clinic, a total of 101 retainers installed by the same professional between June 2008 and January 2018, with an average time of 58.2 months (4.8 years), were analyzed regarding the following factors: survival, cement and failure type. Three types of retainers were used according to the indications found in the literature: filling with Z250 light-cured composite resin, 22 elements; fiberglass post with Z250 light-cured composite resin, 45 elements; and cast metallic core in silver-tin alloy, 34 elements. The retainers were cemented with chemically cured cement, U100, U200, or Panavia F. RESULTS: Data were subjected to Kaplan-Meier analysis (p=0.495). Although the study presented several limitations, no significant differences were observed in the success rates between the types of intra-radicular retainers and the type of cement. The success rates were as follows: metal core, 97.1%; fiberglass post, 95.6%; and filling, 100%. On average, failures occurred at 48.4 months. CONCLUSION: In view of the results, it is possible to conclude that the different retainers evaluated have similar survival rates.

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Abstract This study evaluates the shear bond strength (SBS) of various resin cements to different ceramics. Composite resin cylinders of Z100 were fabricated and cemented to disks of feldspathic ceramic (Creation), leucite-reinforced feldspathic ceramic (Empress I), and densely sintered aluminum oxide ceramic (Procera AllCeram) using five resin cements: Panavia F (PAN), RelyX ARC (ARC), RelyX Unicem (RXU), RelyX Veneer, and Variolink II. SBS was measured after three days of water storage (baseline) and after artificial aging (180 days of water storage along with 12,000 thermal cycles). Failure mode of fractured specimens also was evaluated. Data were analyzed with Kruskal-Wallis and Mann-Whitney tests (α=0.05). RXU showed 1) the lowest baseline median SBS to feldspathic ceramic, which was not statistically different from PAN; 2) the lowest median baseline SBS to leucite-reinforced feldspathic and densely sintered aluminum-oxide ceramics. All cements performed similarly after aging, except for ARC (median 0.0 MPa) and PAN (median 16.2 MPa) in the densely sintered aluminum-oxide ceramic group. Resin cements perform differently when bonded to different ceramic substrates. While all test resin cements worked similarly in the long-term to feldspathic and leucite-reinforced feldspathic ceramics, only the MDP-containing resin cement provided durable bonds to densely sintered aluminum-oxide ceramic.

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STATEMENT OF PROBLEM: A recommended minimum thickness for monolithic zirconia restorations has not been reported. Assessing a proper thickness that has the necessary load-bearing capacity but also conserves dental hard tissues is essential. PURPOSE: The purpose of this in vitro study was to evaluate the effect of thickness and surface modifications on monolithic zirconia after simulated masticatory stresses. MATERIAL AND METHODS: Monolithic zirconia disks (10 mm in diameter) were fabricated with 1.3 mm and 0.8 mm thicknesses. For each thickness, 21 disks were fabricated. The specimens of each group were further divided into 3 subgroups (n=7) according to the surface treatments applied: untreated (control), airborne-particle abrasion with 50-µm Al2O3 particles at a pressure of 400 kPa at 10 mm, and grinding with a diamond rotary instrument followed by polishing. The biaxial flexure strength was determined by using a piston-on-3-balls technique in a universal testing machine. Flexural loading was applied with a 1.4-mm diameter steel cylinder, centered on the disk, at a crosshead speed of 0.5 mm/min until fracture occurred. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses were performed. The data were statistically analyzed with 2-way ANOVA, Tamhane T2, 1-way ANOVA, and Student t tests (α=.05). RESULTS: The 1.3-mm specimens had significantly higher flexural strength than the 0.8-mm specimens (P<.05). Airborne-particle abrasion significantly increased the flexural strength (P<.05). Grinding and polishing did not affect the flexural strength of the specimens (P>.05). CONCLUSIONS: The mean flexural strength of 0.8-mm and 1.3-mm thick monolithic zirconia was greater than reported masticatory forces. Airborne-particle abrasion increased the flexural strength of monolithic zirconia. Grinding did not affect flexural strength if subsequently polished.

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