Effect of Radiotherapy and Taper of Root Canal Preparation on the Biomechanical Behavior of Mesial Roots of Mandibular Molars.

Introduction: This study aimed to investigate the effect of radiotherapy and taper of root canal preparation on the biomechanical behavior of mesial roots of mandibular molars.

Methods: Eighty mandibular molars with 2 canals in the mesial root were randomly allocated into 2 groups (n = 40): one group underwent irradiation (60 Gy), while the other did not. Subsequently, the mesial roots were sectioned and each group was subdivided into 5 subgroups (n = 8), according to the preparation taper: no preparation (control); 25.

Does partial adhesive preparation design and finish line depth influence trueness and precision of intraoral scanners?

Statement Of Problem: Intraoral scanners (IOSs) are widely used for partial-coverage adhesive restorations, but data on their performance in such preparations with complex geometries are sparse.

Purpose: The purpose of this in vitro study was to investigate whether the partial-coverage adhesive preparation design and finish line depth affect the trueness and precision of different IOSs.

Material And Methods: Seven partial-coverage adhesive preparation designs (4 different onlays, 2 endocrowns, and 1 occlusal veneer) were tested on copies of the same tooth placed in a typodont mounted on a mannequin.

Should finishing, polishing or glazing be performed after grinding YSZ ceramics? A systematic review and meta-analysis.

The present systematic review and meta-analysis aimed to assess the characteristics and consequences of post-processing methods after grinding procedures in YSZ ceramics on its surface roughness and flexural strength. The protocol of this review was made prospectively and is available online in the PROSPERO database (link). Literature searches on PubMed/MEDLINE, EMBASE, Lilacs, Web of Science and Scopus were conducted on December 2022 to select in vitro studies written in English, without publishing-date restrictions, that considered surface characteristics and mechanical properties of YSZ ceramics submitted to grinding and subsequent post-processing surface treatments as an attempt to revert the effect induced by grinding.

Layering of discolored substrates with high-value opaque composites for CAD-CAM monolithic ceramics.

Statement Of Problem: Severely discolored substrates have been shown to limit the use of computer-aided design and computer-aided manufacturing (CAD-CAM) ceramic blocks because they provide insufficient color masking.

Purpose: The purpose of the in vitro study was to evaluate the effect of a layer of high-value opaque composite resin over discolored substrates to determine its masking ability with CAD-CAM ceramics.

Material And Methods: Six ceramic groups (n=10) were tested.

Restorative preferences and choices of dentists and students for restoring endodontically treated teeth: A systematic review of survey studies.

Statement Of Problem: The best protocol to restore endodontically treated teeth is still unclear, with many factors to be considered, including the selection and necessity of a post, the type of coronal restoration, the amount of remaining coronal structure, and the type of luting agent.

Purpose: The purpose of this systematic review was to assess the restorative preferences for endodontically treated teeth between dentists and dental students.

Material And Methods: Survey studies, written in English, of dentists and dental students, which evaluated the use of intracanal posts and other restorative options for endodontically treated teeth, were selected.

Fatigue performance of fully-stabilized zirconia polycrystals monolithic restorations: The effects of surface treatments at the bonding surface.

This study evaluated the distinct conditioning effect of the intaglio surface of bonded fully-stabilized zirconia (FSZ) simplified restorations on the mechanical fatigue behavior of the set prior to and after aging. Ceramic disc shaped specimens (Ø= 10 mm and 1 mm thick) were randomly allocated into 14 groups considering: "surface treatments" (Ctrl: no-treatment; PM: universal primer; GLZ: low-fusing porcelain glaze; SNF: 5 nm SiO nanofilm deposition; AlOx: air-abrasion with aluminum oxide; SiC: air-abrasion with silica-coated aluminum oxide; 7%Si: air-abrasion with 7% silica-coated aluminum oxide); and "aging" (baseline: 24 h at 37 °C in water; or aged: 90 days at 37 °C in water + 12,000 thermal cycles). The discs were treated, luted with resin cement onto the dentin analog, subjected to aging or not, and then tested under a step-stress fatigue test at 20 Hz, 10,000 cycles/step, step-size of 100N starting at 200N, and proceeding until failure detection.

Accelerated loading frequency does not influence the fatigue behavior of polymer infiltrated ceramic network or lithium disilicate glass-ceramic restorations.

This study aimed to evaluate the influence of loading frequency on the fatigue mechanical behavior of adhesively cemented polymer-infiltrated ceramic-network (PICN) and lithium disilicate (LD) simplified monolithic restorations. Thirty (30) disc-shaped specimens (Ø = 10 mm; thickness = 1.0 mm) of each ceramic material (PICN - Enamic, Vita Zahnfabrik or LD - IPS e.

Fatigue performance of adhesively luted glass or polycrystalline CAD-CAM monolithic crowns.

Statement Of Problem: Data comparing the fatigue performance of adhesively luted glass or polycrystalline ceramic systems for computer-aided design and computer-aided manufacturing (CAD-CAM) are scarce.

Purpose: The purpose of this in vitro study was to evaluate and compare the fatigue performance of monolithic crowns manufactured from glass or polycrystalline CAD-CAM ceramic systems adhesively luted to a dentin analog.

Materials And Methods: Fifty-four pairs of standardized preparations of dentin analog (NEMA Grade G10) and simplified ceramic crowns of 1.

One-step ceramic primer as surface conditioner: Effect on the load-bearing capacity under fatigue of bonded lithium disilicate ceramic simplified restorations.

The aim of the study was to evaluate the effect of a ceramic primer and its increased passive application on the fatigue performance of adhesively cemented lithium disilicate simplified restorations. Ceramic discs (Ø = 10 mm; thickness = 1.0 mm) were submitted to an in-lab simulation of CAD/CAM milling and allocated into 8 groups (n = 15), considering 2 factors: "surface treatment"- PRIMER, only coupling agent application (Monobond N); HF5+PRIMER, 5% hydrofluoric acid and coupling agent; E&P 20s + 40s and E&P 20s+5min, ceramic etching/priming (Monobond Etch & Prime, E&P) for 20 s of active application followed by 40 s or 5 min of passive application, respectively; and "aging condition"- baseline, storage for 24 h to 5 days; aged, storage for 90 days +12,000 thermal cycles.

Effect of Root Canal Irrigants on the Mechanical Properties of Endodontically Treated Teeth: A Scoping Review.

Introduction: The aim of this study was to identify through a scoping review whether root canal irrigants influence the mechanical properties of endodontically treated teeth, and which properties could be affected. The protocol of this study, available online (https://osf.io/yc9nb/), followed the Joana Briggs Institute guidelines.

Influence of shading technique on mechanical fatigue performance and optical properties of a 4Y-TZP ceramic for monolithic restorations.

This study aimed to evaluate the effect of shading procedures on the fatigue performance and optical properties of an yttria-stabilized tetragonal zirconia polycrystal ceramic (4Y-TZP - stabilized by 4 mol% YO). Disc-shaped specimens were produced at pre-sintered stage and randomly allocated into 5 groups (n=15) considering the shading technique: Ctrl (no pigmentation); Brush 1× and Brush 3× (brushing on 1 or 3 applications, respectively); Immer 2min and Immer 4min (immersion for 2 or 4 min, respectively). Following each pigment application, the specimens were dried in accordance with the manufacturers' guidelines (15 min in a stove at 70 °C) and sintered in a specific furnace.

Comparison of endocrowns made of lithium disilicate glass-ceramic or polymer-infiltrated ceramic networks and direct composite resin restorations: fatigue performance and stress distribution.

This study compared the fatigue performance and the stress distribution of endodontically treated molars restored with endocrowns obtained with lithium disilicate glass-ceramic or a polymer-infiltrated ceramic network, both processed by CAD-CAM, and direct composite restorations. Forty-eight human mandibular molars were randomly assigned into 03 groups (n = 16) and restored with endocrowns (LD - lithium disilicate glass-ceramic or PICN - polymer-infiltrated ceramic network) or with direct composite restorations. Fatigue testing followed a step-stress approach (initial maximum load of 200 N and 5000 cycles, incremental step load of 200N and 10,000 cycles/step, being the specimens loaded until failure or to a maximum of 135,000 cycles at 2800 N).

CAD-CAM milled versus pressed lithium-disilicate monolithic crowns adhesively cemented after distinct surface treatments: Fatigue performance and ceramic surface characteristics.

To evaluate the fatigue failure load (FFL), number of cycles for failure (CFF) and survival probabilities of lithium-disilicate (LD) monolithic crowns manufactured by two processing techniques (pressing vs. CAD/CAM) adhesively cemented to a dentin-analogue material, considering two surface treatments (conventional vs. simplified).

Load-bearing capacity under fatigue and survival rates of adhesively cemented yttrium-stabilized zirconia polycrystal monolithic simplified restorations.

This study evaluated the fatigue failure load, number of cycles for failure and survival probability of 2nd and 3rd generation yttrium-stabilized zirconia (YSZ) adhesively cemented to a dentin analogue substrate. Disc-shaped specimens (n = 10; Ø = 10 mm; thickness = 1.0 mm) were produced from four 2nd generation YSZs (Lava Plus, 3M ESPE; Vita In-Ceram YZ-HT, VITA Zahnfabrik; Zirlux FC, Ivoclar Vivadent; Katana ML-HT, Kuraray) and two 3rd generation YSZs (Katana UTML and Katana STML, Kuraray).

Fatigue failure load of zirconia-reinforced lithium silicate glass ceramic cemented to a dentin analogue: Effect of etching time and hydrofluoric acid concentration.

This study aimed to evaluate the effect of etching time and hydrofluoric acid (HF) concentration on the fatigue failure load and surface characteristics of zirconia-reinforced lithium silicate glass (ZLS) ceramic cemented to a dentin-like, fiber reinforced epoxy resin. Ceramic (Suprinity, VITA) (1.0mm thick) and epoxy resin (2.