Effect of different surface treatments on shear bond strength of zirconia with various yttria contents.

Background: Achieving a stable bond with zirconia requires mechanical and chemical bonding methods. Information regarding the optimal treatment method for zirconia with varying yttrium content is scarce. This study evaluated the effect of different surface treatments on the shear bond strength of zirconia with various yttria contents.

Fracture strength and marginal and internal adaptation of lithium disilicate and hybrid ceramic endocrowns and non-retentive overlays for endodontically treated molar teeth.

Background: With the advances in the adhesive science, several conservative treatment options such as non-retentive overlays have been suggested for endodontically treated posterior teeth. However, information is scarce regarding the fracture strength and adaptation of non-retentive overlays compared with endocrowns, and the effect of material type in this respect. Thus, this study aimed to assess the fracture strength and internal and marginal adaptation of lithium disilicate (LDS) and hybrid ceramic endocrowns and non-retentive overlays for endodontically treated molar teeth.

Effect of different surface treatments on retention and fracture strength of zirconia crowns over Ti-base zirconia abutments.

Background: Limited evidence suggested different outcomes of surface treatment methods on zirconia abutments and crowns. Therefore, we investigated the effect of grooving, hot etching, and airborne particle abrasion (APA) methods on zirconia crowns over Ti-base zirconia abutments retention and fracture strength.

Materials And Methods: In this study, 110 zirconia crowns and abutments were divided into five groups, including APA for crown and grooved zirconia abutment (APACr-GrAb), APA for crown and hot etching zirconia abutment (APACr-HtAb), grooved modified zirconia crown and APA for zirconia abutments (GrCr-APAAb), hot etching modified zirconia crown and APA for zirconia abutments (HtCr-APAAb), and APA for both crown and zirconia abutments (control group).

Comparison of Internal and Marginal Adaptation of Endocrowns at Different Depths Fabricated by the Digital and Conventional Impression Techniques: Internal and Marginal Fit of Endocrowns.

Sufficient information is not available regarding the comparative accuracy of digital and conventional impression techniques at different depths for the fabrication of endocrown restorations. Thus, this study aimed to compare the marginal (M) and internal (I) adaptation of endocrowns at different depths fabricated by the digital and conventional impression techniques. In this in vitro study, two endodontically treated molar teeth with 2- and 4-mm cavity depths were used for the fabrication of endocrowns.

In Vitro Effect of the Length of Relocated Cervical Margin with Casting Post and Core, Prefabricated Fiber Post, and Polyethylene Fiber with a Composite Core on Fracture Resistance and Marginal Integrity.

Objective: This study aimed to assess the effect of length of the relocated cervical margin with casting post and core (CP), prefabricated fiber post and composite core (PFP), and polyethylene fiber-reinforced composite (PEFRC) on fracture resistance and marginal integrity.

Materials And Methods: In this in vitro study, 70 sound human maxillary premolars were divided into seven groups according to the type of post and core system and length of the relocated cervical margin ( = 10): control (no preparation), PFP-3, PEFRC-3, CP-3 with 3 mm of cervical margin relocation (CMR), PFP-6, PEFRC-6, and CP-6 (with 6 mm of CMR). The samples were restored with zirconia crowns (except the control group).

Comparison of marginal leakage and retentive strength of implant-supported milled zirconia and cobalt-chromium copings cemented with different temporary cements.

Background: Few studies assessed the effect of coping material (particularly milled metal copings) on the retentive strength of cements and reported contradictory results. Thus, this study aims to assess the marginal leakage and retentive strength of implant-supported milled zirconia and cobalt-chromium (Co-Cr) copings cemented with different temporary cements.

Materials And Methods: In this study, Zirconia and Co-Cr copings were fabricated on 100 straight titanium abutments.

Fracture resistance and failure mode of endodontically treated premolars reconstructed by different preparation approaches: Cervical margin relocation and crown lengthening with complete and partial ferrule with three different post and core systems.

Purpose: To assess the fracture resistance and failure mode of endodontically treated premolars reconstructed by different preparation approaches: cervical margin relocation (CMR) and crown lengthening (CL) with complete ferrule (CLF) and partial ferrule (CLPF) with three different post and core systems.

Materials And Methods: In this in vitro study, 100 maxillary premolars were assigned to the following 10 groups according to their preparation approach and type of post and core system (n = 10): (I) control (intact teeth), (II) prefabricated fiber post (PFP) and composite core with CMR (PFP-CMR), (III) polyethylene fiber-reinforced composite (PEFRC) with CMR (PEFRC-CMR), (IV) casting post (CP) and core with CMR (CP-CMR), (V) PFP-CLPF, (VI) PEFRC-CLPF, (VII) CP-CLPF, (VIII) PFP-CLF, (IX) PEFRC-CLF, and (X) CP-CLF. After thermomechanical loading, the fracture resistance and failure mode were assessed.

Comparison of mechanical properties, surface roughness, and color stability of 3D-printed and conventional heat-polymerizing denture base materials.

Statement Of Problem: Studies on the mechanical, optical, and surface properties of 3-dimensionally (3D) printed denture base materials are scarce, and those available have reported conflicting results.

Purpose: The purpose of this in vitro study was to compare the mechanical properties, surface roughness, and color stability of 3D-printed and conventional heat-polymerizing denture base materials.

Material And Methods: A total of 34 rectangular specimens (64×10×3.

Effect of orthodontic bonding with different surface treatments on color stability and translucency of full cubic stabilized zirconia after coffee thermocycling.

Objective: To assess the color stability and translucency of full cubic stabilized zirconia (FSZ) following orthodontic bonding with different surface treatments and coffee thermocycling (CTC).

Methods: This study was conducted on 120 disc-shaped specimens of FSZ. Thirty specimens were selected as the control group and remained intact.

Shear bond strength of different luting agents to polyether ether ketone.

Background: Polyether ether ketone (PEEK) was recently introduced to dentistry. However, difficulty in provision of a strong durable bond is its main drawback. Thus, precise surface treatment and use of a suitable luting agent are imperative for bonding of PEEK restorations.

Marginal and internal fit and fracture resistance of three-unit provisional restorations fabricated by additive, subtractive, and conventional methods.

Objectives: To compare the marginal and internal fit and fracture resistance of three-unit provisional fixed dental prostheses (FDPs) fabricated by additive, subtractive, and conventional methods.

Material And Methods: Eighty 3-unit FDPs were fabricated on metal dies of the maxillary right second premolar and second molar by four different techniques (n = 20): The direct method by using autopolymerizing polymethyl methacrylate (PMMA), indirect method by the compression molding technique, subtractive manufacturing by using PMMA blocks, and additive manufacturing by using digital light processing technology. The adaptation of restorations at the marginal, axial, cuspal, and fossa areas was assessed by using the silicone replica technique.

Effect of Different Surface Treatments and Orthodontic Bracket Type on Shear Bond Strength of High-Translucent Zirconia: An In Vitro Study.

Objective: Considering the increasing number of adults seeking orthodontic treatment, and the possible need for bracket bonding to monolithic zirconia restorations, knowledge about the preferred type of bracket (metal/ceramic) and the most efficient surface treatment is imperative to achieve acceptable shear bond strength (SBS). This study aimed to assess the effect of different surface treatments and orthodontic bracket types on SBS of high-translucent zirconia.

Materials And Methods: Totally, 248 disc-shaped zirconia specimens were assigned to two groups for bonding to metal and ceramic brackets.

Three-dimensional accuracy of innovative implant-level impression techniques with plastic snap-on impression copings.

Background: Several studies have assessed the accuracy of the indirect snap-on impression technique. However, some impression techniques that utilize plastic snap-on impression copings have not yet been investigated.

Objectives: This study aimed to assess the three-dimensional (3D) accuracy of innovative implant-level impression techniques with plastic impression copings and the splinted open-tray technique with metal impression copings.

Effect of different surface treatments on surface roughness and flexural strength of repaired 3D-printed denture base: An in vitro study.

Statement Of Problem: Information regarding three-dimensional-printed (3D-printed) dentures, especially when using the additive manufacturing technique, and the repair strength of this type of denture is sparse.

Purpose: The purpose of this in vitro study was to assess the effect of different surface treatments on the surface roughness and flexural strength of repaired 3D-printed denture base.

Material And Methods: One hundred and twenty 3D-printed bar-shaped specimens were fabricated from acrylic resin and divided into 6 groups (n=20).

Marginal gap of monolithic zirconia endocrowns fabricated by using digital scanning and conventional impressions.

Statement Of Problem: The digital scanning technique has been introduced as an alternative to the conventional impression technique for the fabrication of fixed restorations. However, adequate information is not available on the efficacy of digital scanning for the fabrication of endocrowns regarding their marginal accuracy.

Purpose: The purpose of this in vitro study was to compare the marginal gap of endocrowns fabricated by computer-aided design and computer-aided manufacturing (CAD-CAM) technology and digital scanning and conventional impression techniques.

Marginal adaptation of zirconia-reinforced lithium silicate overlays with different preparation designs.

Objective: Following the advent of strong adhesive bonding, the conservative tooth preparation designs without a retentive form gained increasing popularity. This study aimed to evaluate the marginal adaptation of zirconia-reinforced lithium silicate (ZLS) overlays with different preparation designs.

Materials And Methods: Forty sound human maxillary first molars were collected and divided into four groups (n = 10) according to their preparation design for the fabrication of ZLS overlays: (O) anatomical occlusal reduction, (OS) anatomical occlusal reduction with rounded shoulder, (OG) anatomical occlusal reduction with a central groove, and (OSG) anatomical occlusal reduction with rounded shoulder and central groove.

Effect of Tooth Preparation Design on Fracture Resistance of Zirconia-Reinforced Lithium Silicate Overlays.

Purpose: To assess the effect of tooth preparation design on fracture resistance of zirconia-reinforced lithium silicate overlays.

Materials And Methods: This study evaluated 50 human maxillary first molars with no caries, restorations or anatomical defects. The teeth were randomly divided into five groups (n = 10/group) based on preparation design for the fabrication of overlay restorations: (O) anatomical occlusal reduction, (OS) anatomical occlusal reduction with round shoulder preparation, (OG) anatomical occlusal reduction with a central groove, (OSG) anatomical occlusal reduction with round shoulder preparation and central groove, and (C) no preparation of tooth (control group).

Comparison of Success Rates of Cone Beam Computed Tomography in the Retrieval of Metal-Ceramic vs All-Ceramic Implant-Supported Restorations: An In Vitro Study.

Purpose: To assess the success rates of cone beam computed tomography (CBCT) in identifying the locations and directions of abutment screw access holes (ASAHs) in metal-ceramic and all-ceramic implant restorations.

Materials And Methods: Thirty-two implants were inserted into four clear acrylic casts. Metal-ceramic and all-ceramic crowns were placed on the inserted implants in two successive tasks.

Comparison of Salivary Calcium Level in Dentulous and Edentulous Patients.

Objectives: Calcium is an inorganic component of the saliva, which is especially important in oral and dental health. This study sought to compare unstimulated salivary calcium level of dentulous and edentulous patients.

Materials And Methods: This case-control study was conducted on 72 participants, including 36 dentulous and 36 edentulous patients.

Coronal Microleakage of Teeth Restored with Cast Posts and Cores Cemented with Four Different Luting Agents after Thermocycling.

Purpose: The apical seal provided by a root canal filling may be breached via coronal leakage. This study aimed to compare the teeth restored with custom-made cast metal posts and cores cemented with different luting agents in terms of coronal microleakage after thermocycling.

Materials And Methods: This in vitro study was conducted on 32 extracted single-canal teeth.

Evaluation of the success rate of cone beam computed tomography in determining the location and direction of screw access holes in cement-retained implant-supported prostheses: An in vitro study.

Statement Of Problem: Cement-retained implant-supported restorations have advantages over screw-retained restorations but are difficult to retrieve. Identifying the approximate location of the screw access hole (SAH) may reduce damage to the prosthesis.

Purpose: The purpose of this in vitro study was to evaluate the ability of cone beam computed tomography (CBCT) imaging to determine the location and direction of SAHs in cement-retained implant prostheses.

Frequency of different maxillary sinus septal patterns found on cone-beam computed tomography and predicting the associated risk of sinus membrane perforation during sinus lifting.

Purpose: Analyzing different patterns of maxillary sinus septa in cone-beam computed tomography (CBCT) images and predicting maxillary sinus membrane perforations.

Materials And Methods: In this cross-sectional study, CBCT images of 222 patients ranging from 20 to 81 years old were evaluated. One hundred fifty-two patients (93 females and 59 males) who had maxillary sinus septa in axial views were included in this study.

The Accuracy of Four Impression-making Techniques in Angulated Implants Based on Vertical Gap.

Statement Of The Problem: Precision of the impression taken from implant positions significantly determines accurate fit of implant-supported prostheses. An imprecise impression may produce prosthesis misfit.

Purpose: This study aimed to evaluate the accuracy of four impression-making techniques for angulated implants by stereomicroscope through measuring the vertical marginal gaps between the cemented metal framework and the implant analog.

effect of chlorhexidine gel on torque and detorque values of implant abutment screw.

Purpose: Use of chlorhexidine (CHX) gel to eliminate the malodor of implant cavity may decrease the friction coefficient and effective preload and result in abutment screw loosening. This study aimed to assess the effect of CHX gel on the preload, torque, and detorque values.

Materials And Methods: This in vitro experimental study was conducted on three groups of five implants.

The effect of repeated torque in small diameter implants with machined and premachined abutments.

Background: Detorquing value is an important factor in the amount of preload stresses during abutment screw fastening. This study evaluated the percentage of detorque values in two-piece machined titanium and premachined cast abutments in small diameter implants.

Materials And Methods: Three groups of five samples were evaluated.