In vitro comparative study between complete arch conventional implant impressions and digital implant scans with scannable pick-up impression copings.

STATEMENT OF PROBLEM: Intraoral digital scan techniques have been widely used and sufficient evidence supports this technique in partially edentulous patients. However, the evidence supporting the use of intraoral scanners (IOSs) for edentulous patients is limited. PURPOSE: The purpose of this in vitro study was to measure and compare the accuracy of complete arch conventional pick-up implant impressions with open and closed trays, complete arch digital implant scans with IOSs, and 3-dimensional (3D) printed casts from complete arch digital implant scans. MATERIAL AND METHODS: Six implants were placed in a mandibular model. Scannable pick-up impression copings were inserted in the implants, scanned with a reference scanner, and exported in standard tessellation language (STL) format (Group Control). Splinted open-tray pick-up impressions (Group OT, n=5) and closed-tray pick-up impressions (Group CT, n=5) were made, and stone casts were fabricated. Digital scans (Group DS, n=5) were made with an IOS, and the STL files were exported to fabricate 3D printed casts (Group STL, n=5). Scannable pick-up impression copings were inserted in the dental implant analogs in Groups OT, CT, and STL and scanned with the reference scanner. Using a 3D inspection software program, the recording techniques were compared with the control. Root mean square (RMS) values were calculated from the control, and superimposed digitized casts from different recording techniques. Analysis of variance was used to determine differences in RMS values, and theTukey post hoc test was used to determine difference between different groups. RESULTS: Group CT had the lowest mean dimensional difference when superimposed with Group Control, followed by Groups DS, OT, and STL. Significant differences were found in RMS values between Control and digitized casts fabricated with different techniques (P<.05). The post hoc Tukey test revealed that Group DS (P<.05) was significantly different from the other groups, while no significant difference was found among Groups CT, OT, and STL (P>.05). CONCLUSIONS: Based on the findings of the present study, 3D printed casts from digital scans have the same accuracy as stone casts from conventional impressions in complete arch implant cases. Intraoral scans had the highest accuracy. Complete arch pick-up impression techniques using dual-functioning scannable pick-up impression copings are as accurate as splinted complete arch pick-up impressions.

Influence of universal adhesives and silane coupling primer on bonding performance to CAD-CAM resin-based composites: A laboratory investigation.

OBJECTIVE: Obtaining strong resin bonds to computer-aided design and computer-aided manufacturing (CAD-CAM) resin-based composites with dispersed fillers (CCRBCs) poses a challenge. Therefore, this study aimed to assess the effect of three universal adhesives and a two-component silane coupling agent on the shear bond strength to three (CCRBCs). MATERIALS AND METHODS: Eight hundred and sixty-four specimens of Brilliant Crios, Lava Ultimate, and Tetric CAD were polished or grit blasted, bonded with Adhese Universal DC, One Coat 7 Universal (OC7), and Scotchbond Universal Plus Adhesive (SBU) with or without a silane primer. Shear bond strength was measured after 24 h and 10,000 thermocycles. Linear regressions were performed (α = 0.05). RESULTS: After thermocycling, bond strengths were similar for the universal adhesives on polished Brilliant Crios and Lava Ultimate (p ≥ 0.408). Grit blasted Tetric CAD showed no significant differences (p ≥ 0.096). The silane primer had minimal impact on grit blasted Tetric CAD (p ≥ 0.384). The silane primer increased the bond strength of OC7 to Brilliant Crios (p = 0.001) but decreased the adhesion of SBU to Brilliant Crios and Lava Ultimate (p ≤ 0.018). CONCLUSIONS: Bond strength of universal adhesives varied with CCRBC type. The two-component silane coupling agent showed mixed effects on adhesive performance. CLINICAL SIGNIFICANCE: Selecting universal adhesives from the same CCRBC product line does not always guarantee superior bond strength. The efficacy of silane coupling agents differs based on the bonding substrate.

How to Bond to Current CAD/CAM Ceramics.

The clinical quality and longevity of increasingly popular resin-bonded CAD/CAM ceramic restorations depends greatly on the strength and durability of the resin-ceramic bond. With a diverse array of ceramic materials available, the choice of ceramic bonding protocol is highly influenced by the specific ceramic's type and composition. Typically, this protocol encompasses a surface pretreatment step followed by the application of a priming agent. This article provides a comprehensive update on current resin-bonding protocols for the most commonly used CAD/CAM ceramics.

From Minimally Invasive Tooth Extraction to Final Chairside Fabricated Restoration: A Microscopically and Digitally Driven Full Workflow for Single-Implant Treatment.

Technical advances in such fields as optical magnification (eg, loupes, microscopes), microsurgical instruments, bone and soft-tissue grafting materials, and digital dentistry have paved the way for dentists to be able to provide all the necessary specialties for a state-of-art single-tooth replacement treatment under one roof in their clinics, without having to involve a technical laboratory. This case report demonstrates a routine complete chairside digital workflow using minimally invasive and microscopic techniques in every stage of treatment, from tooth extraction and socket preservation, to implant insertion and soft-tissue management, to delivery of the final chairside digital zirconia full-anatomic supraconstruction. In addition to describing the intent of minimally invasive tooth extraction and socket preservation, this article illustrates how to perform a vestibular split rolling flap procedure and discusses its benefits. The goal of this digitally driven single-implant treatment was to achieve restoration as close as possible to the original condition.

Evaluation of marginal and internal fit of single crowns manufactured with an analog workflow and three CAD-CAM systems: A prospective clinical study.

PURPOSE: This prospective clinical study evaluated and compared the marginal and internal fit of crowns fabricated with an analog workflow and three different computer-aided design and computer-aided manufacturing (CAD-CAM) systems. MATERIALS AND METHODS: Twenty-five participants in need of a single complete-coverage molar or premolar crown were recruited in the study. Twenty-two completed the study, and three participants dropped out. Teeth were prepared according to a standardized protocol by one operator. For each participant, one final impression was made with polyether material (PP) and three intraoral scanners: CEREC Omnicam (C), Planmeca Planscan (PM), and True Definition (TR). For the PP group, crowns were fabricated with a pressable lithium disilicate ceramic, whereas for the other three groups (C, PM, and TR), crowns were designed and milled with dedicated CAD-CAM systems and materials. Marginal (vertical and horizontal) and internal discrepancies between the crowns and tooth preparation were measured at various locations with digital superimposition software. Data was analyzed for normality with Kolmogorov-Smirnov and Shapiro-Wilk tests and then compared with one-way ANOVA and Kruskal-Wallis tests. RESULTS: Mean vertical marginal gap values were 92.18 ± 141.41 µm (PP), 150.12 ± 138.06 µm (C), 129.07 ± 109.96 µm (PM), and 135.09 ± 112.03 µm (TR). PP group had statistically significantly smaller vertical marginal discrepancy (p = 0.001) than all other groups, whereas no significant difference was detected among the three CAD-CAM systems (C, PM, and TR). Horizontal marginal discrepancies were 104.93 ± 111.96 µm (PP), 89.49 ± 119.66 µm (C), 113.36 ± 128.49 µm (PM), and 136.39 ± 142.52 µm (TR). A significant difference was detected only between C and TR (p < 0.0001). Values for the internal fit were 128.40 ± 49.31µm (PP), 190.70 ± 69.79µm (C), 146.30 ± 57.70 µm (PM), and 168.20 ± 86.67 µm (TR). The PP group had a statistically significant smaller internal discrepancy than C (p < 0.0001) and TR groups (p = 0.001), whereas no significant difference was found compared to the PM group. CONCLUSION: Posterior crowns fabricated with CAD-CAM systems showed vertical margin discrepancy greater than 120 µm. Only crowns fabricated with the conventional methodology had vertical margins below 100 µm. Horizontal marginal discrepancy was different among all groups, and only CEREC CAD-CAM was below 100 µm. Internal discrepancy was less for crowns fabricated with an analog workflow.

Implant position and guided placement for in-house-produced CAD/CAM restorations with titanium (Ti)-bases.

Digital dentistry has contributed to the evolution and simplification of dental implantology over the last decade. The incorporation of intraoral scanners, CBCT, 3D implant-planning software, and CAD/CAM systems makes prosthetically driven implantology a straightforward process. Such digital resources for treatment planning and execution, following evidence-based concepts, have the ability to improve the long-term esthetics and function of implant-supported restorations as well the long-term survival of dental implants. Dental implants are frequently considered as the first treatment option for replacing failing or missing teeth. However, their use in the esthetic zone remains a challenge for many clinicians. The present article provides clinical guidelines for ideal implant positioning employing computer-guided surgery and chairside CAD/CAM-fabricated provisional and definitive restorations with titanium (Ti)-bases for successful prosthetic outcomes, optimizing gingival architecture, and decreasing overall treatment duration. (Int J Comput Dent 2023;26(1):75-0; doi: 10.3290/j.ijcd.b3818287).

Deep margin elevation-Present status and future directions.

OBJECTIVE: Deep margin elevation (DME) is a treatment approach to relocate the cervical margin of teeth with subgingival defects to a supragingival position with a direct restoration to facilitate rubber dam isolation, impression taking, and bonding of indirect restorations. This article provides an overview of the current scientific evidence on DME and future directions for research. OVERVIEW: The review included 38 studies on DME, most conducted in vitro. These studies indicate that DME has no detrimental effect on the fracture resistance of restored teeth. Evidence on the impact of DME on marginal quality is conflicting, but most in vitro studies observed no negative effect. Clinical studies, most comprising small patient cohorts, demonstrated favorable restorative outcomes and suggest that DME restorations made with scrupulous care are compatible with periodontal health. Bleeding on probing may occur more frequently at sites with DME, though evidence on this is not unequivocal. CONCLUSIONS: Current evidence, based largely on laboratory studies and limited clinical data, supports DME as a viable approach to restore teeth with localized subgingival defects. However, further clinical studies with long-term follow-ups are required to provide corroborative evidence. CLINICAL SIGNIFICANCE: Current evidence suggests that DME is a viable approach to restore teeth with localized subgingival defects as a possible alternative to surgical crown lengthening. Proper working field isolation, meticulous care in the bonding and buildup procedure, and biofilm removal through patient-performed oral hygiene and professional maintenance care are crucial. As scant clinical trial-based evidence is available today, further research is needed to evaluate the long-term performance of DME restorations and their impact on periodontal health.

Digital Smile Design and Fabrication of CAD/CAM Restorations in a Complex Esthetic Case.

Analog design protocols through the use of wax-ups are highly variable, technique sensitive, and operator dependent. Current digital smile design and treatment planning tools facilitate simplified processes based on the patient's face as well as specific esthetic and functional needs of the individual patient. The initial smile design achieved with an advanced and novel smile design software enables a straightforward treatment plan and execution, even in complex esthetic situations where various restorations are needed. This case report describes the clinical and laboratory steps to address the esthetic and functional requirements of a patient with complex restorative needs using a complete digital workflow.

Digital Implant Therapy for the Edentulous Patient.

Numerous treatment modalities describing surgical and prosthetic techniques for treating edentulous patients with dental implants have been published during the past 30 years. With the many recent advancements in software, hardware, and biomaterials, the clinical steps for full-arch guided implant placement, immediate provisionalization, and fabrication of the definitive prosthesis have changed significantly. The use of new digital implant components, intraoral scanners, and 3D printing helps clinicians and dental technicians streamline this treatment modality while reducing chairtime and clinical complications. This case report describes the implant therapy for an edentulous patient with a step-by-step clinical workflow.

Current Adhesive Protocols for Indirect Ceramic Restorations.

Indirect ceramic restorations are commonly used to restore function and esthetics of vital and nonvital teeth as well as dental implants. With advancements in digital dentistry and the massive adoption of computer-aided design/computer-aided manufacturing (CAD/CAM) systems, clinicians and dental assistants are now more involved in the manufacturing process of indirect ceramic restorations and need to understand the best clinical indication for each material and its respective adhesive protocols.

Current Protocols for Resin-Bonded Dental Ceramics.

Resin-bonded ceramic restorations are common treatment options. Clinical longevity of resin-bonded ceramic restorations depends on the quality and durability of the resin-ceramic bond. The type and composition of the specific ceramic determines the selection of the most effective bonding protocol. Such protocol typically includes a surface pretreatment step followed by application of a priming agent. Understanding of fundamental ceramic properties and chemical compositions enables the clinician to make proper material selection decisions for clinically successful and long-lasting restorations. Based on research accrued over the past decades, this article reviews and discusses current resin-bonding protocols to most commonly used dental ceramics.

Full digital workflow to resolve angled adjacent dental implants: A dental technique.

The digital acquisition, fabrication process, and delivery of computer-aided design and computer-aided manufacture (CAD-CAM) implant-supported restorations on angled adjacent implants are described. The proximal surface of a scan post was modified for correct adaptation, permitting an accurate digital scan of adjacent implants in 1 step. Definitive screw-retained splinted implant-supported restorations were designed and milled in a zirconia material and delivered with a combined extraoral and intraoral cementation protocol.

Analysis of the mesh resolution of an .STL exported from an intraoral scanner file.

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.

The Computer Aided Design/press technique: Fabrication of zirconia-reinforced lithium disilicate restorations for treatment of extensive noncarious cervical lesions.

OBJECTIVE: The aim of this case report is to present the CAD/Press technique; a workflow that combines digital design, milled, or 3D printed burnout molds, and a new pressable ceramic material for the treatment of extensive noncarious lesions with minimal invasive indirect ceramic restorations. CLINICAL CONSIDERATIONS: Clinical decisions from material selection, preparation design, manufacturing techniques to adhesive protocols will be discussed, as they are important factors for achieving long-term clinical success while preserving healthy tooth structure. CLINICAL SIGNIFICANCE: The presented workflow aims to ease clinical decisions when restoring extensive cases with indirect restorations and show clinicians a workflow combining several techniques.

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.

Digital Implant Planning and Surgical Guides: Tools for Clinical Success.

Digital technologies have fundamentally changed treatment planning, surgical placement, and restoration of dental implants, improving clinical success while saving valuable chairtime. Intraoral scanners (IOS), cone-beam computed tomography (CBCT), 3D implant planning software, and CAD/CAM systems that fabricate surgical guides and provisional and definitive restorations have become standard tools for precise implant placement and ideal restoration design, which are essential for optimal and long-term esthetic and functional success. This article summarizes clinical guidelines for integration of digital technologies in implant dentistry.

The Digital Clone: Intraoral Scanning, Face Scans and Cone Beam Computed Tomography Integration for Diagnosis and Treatment Planning.

The purpose of this article is to synthesize different technologies that are available for the creation of a virtual patient, "the digital clone" because the data can be used for diagnosis as well as treatment planning. The role of facial scans, 3-dimensional intraoral scans as well as the cone beam computed tomography in the creation of a digital clone is discussed in detail. A step-by-step guide is created for the reader for integration of the intraoral scan data with the cone beam computed tomography Dicom data to create a digital clone.

Esthetic Restoration of Severely Discolored and Periodontically Compromised Teeth With Novel Digital Workflow.

The objective of this article is to describe to clinicians and dental technicians a novel approach regarding a digital workflow that combines the use of different CAD/CAM software programs to successfully address the challenge of achieving esthetic success in difficult cases. The "ReShape" concept for morphological and esthetic enhancement of monolithic ceramic restorations presents a unique digital workflow that facilitates production of restorations with natural morphology and surface texture, less need for post-milling characterizations, and excellent esthetic results. This approach is aimed at improving the quality of monolithic ceramic restorations fabricated via CAD/CAM technology by combining the acquisition software of an intraoral scanner with a design software.

Esthetic Restoration of Severely Discolored and Periodontically Compromised Teeth With Novel Digital Workflow.

The implementation of digital technologies for interdisciplinary treatment planning and fabrication of monolithic ceramic restorations is a standard protocol in modern dentistry. Teeth with severe discoloration, soft-tissue defects, and multiple diastemas are common challenges clinicians face when performing restorative dentistry. The objective of this article is to describe to clinicians and dental technicians a novel approach regarding a digital workflow that combines the use of different CAD/CAM software programs to successfully address the challenge of achieving esthetic success in difficult cases. The "ReShape" concept for morphological and esthetic enhancement of monolithic ceramic restorations presents a unique digital workflow that facilitates production of restorations with natural morphology and surface texture, less need for post-milling characterizations, and excellent esthetic results. This approach is aimed at improving the quality of monolithic ceramic restorations fabricated via CAD/CAM technology by combining the acquisition software of an intraoral scanner with a design software.

Effect of surface treatment and cleaning on the bond strength to polymer-infiltrated ceramic network CAD-CAM material.

STATEMENT OF PROBLEM: Optimal composite resin bonds to polymer-infiltrated ceramic network (PICN) computer-aided design and computer-aided manufacturing (CAD-CAM) materials are essential for clinical success. However, comparative bond strength studies on the influence of different etching and cleaning methods on these materials are lacking. PURPOSE: The purpose of this in vitro study was to measure and compare the microshear bond strength (µSBS) of a composite resin cement with that of a PICN material after different surface treatment and cleaning methods. MATERIAL AND METHODS: Seventy specimens of a CAD-CAM PICN were divided into 7 groups (n=10): no treatment (control), hydrofluoric acid etching for 20 seconds (HF20), 60 seconds (HF60), 120 seconds (HF120), HF20 + phosphoric acid for 60 seconds and ultrasonic bath for 5 minutes, HF60 + PH, and HF120 + PH. After surface treatment, a silane coupling agent and composite resin cement were applied. Microshear bond strength was determined, and data were analyzed with 1-way ANOVA and Tukey post hoc multiple comparison tests (α=.05). RESULTS: All HF acid treatments resulted in a significant increase in bond strength to the polymer-infiltrated ceramic network material (P=.02). Bond strength values for HF etching for 20 seconds were significantly lower than those for 60 seconds and 120 seconds (P=.034). No difference was found between 60 seconds and 120 seconds of HF etching time (P=.986). Additional surface treatment with phosphoric acid 60 seconds and ultrasonic bath 5 minutes did not improve the bond strength beyond values obtained by hydrofluoric acid treatment only (P=.834). Most failures were cohesive. CONCLUSIONS: Acid etching and surface treatment have significant effects on composite resin bond strength to a PICN CAD-CAM material. HF etching for 60 seconds or 120 seconds provides the highest bond strengths. Cleaning methods after etching did not have any significant effect on bond strength.