Biomechanical performance of three fiberglass post cementation techniques: Imaging, in vitro, and in silico analysis.

Purpose: The structural integrity of the resin cement layer, the bond strength, and the biomechanical behavior of different fiberglass post cementation techniques were evaluated.

Methods: Thirty-three bovine incisors were divided into three groups (n = 11): conventional fiberglass post (CFP), conventional fiberglass post in flared root canals (CFL), and relined fiberglass post (RFP). Six specimens from each group were submitted for high-resolution microcomputed tomography (μCT) to evaluate the integrity and presence/volume of voids at the resin cement layer.

Clinical outcomes of minimally invasive ceramic restorations executed by dentists with different levels of experience. Blind and prospective clinical study.

Purpose: To evaluate the clinical outcomes of minimally invasive ceramic restorations executed by dentists with different levels of experience.

Methods: Sixteen professionals were divided into 4 groups according to their experience levels. These included G1: up to 2 years since graduation, G2: 2-5 years, G3: 5-10 years, and G4: more than 10 years.

An alternative 2-step cementation technique to reduce polymerization shrinkage stress in root canals: a case report.

The functional rehabilitation of teeth with endodontic involvement and substantial loss of coronal structure can be a challenging scenario. The use of fiber-reinforced posts (FRPs) promotes retention and supports the restoration. The main cause of failure associated with the use of FRPs is the debonding of the post, mainly due to polymerization contraction or incorporation of voids in the thick resin cement layer during the cementation protocol.

Influence of resin cement thickness and temperature variation on mechanical behavior of dental ceramic fragment restoration.

To evaluate the stress behavior of ceramic fragment restoration, varying the thickness of the cement layer and intraoral temperature variation. A solid model of a upper lateral incisor was obtained and a defect at enamel distal/incisal edge was restored with a ceramic fragment. Based on this initial model, 4 different models (M) were built: M1 - absence of cement layer (CL) (0 μm of thickness); M2 - CL with an uniform thickness of 50 μm; M3 - CL with 50 μm at the margin of ceramics and 100 μm in the inner area far from margins; M4 - CL with 50 μm at the margin of ceramics and 200 μm in the inner area far from margins.

Minimally Invasive Ceramic Restorations: A Step-by-Step Clinical Approach.

Minimally invasive treatments are a dominant trend in dentistry. Due to the evolution of adhesive materials and ceramics, minimalistic ceramic restorations have been proposed as alternative treatment options to avoid unnecessary tooth reduction. The aim of this article is to show a clinical protocol for the correct diagnosis, treatment planning, and execution of minimally invasive ceramic veneers.

Sealing the Screw Access Channel with Polytetrafluoroethylene Tape: Advantages of the Technique.

The aim of this article is to describe the procedure for sealing the screw access channel using plastic tape, polytetrafluoroethylene, in screw- or cement-retained implant-supported prostheses. This technique is viable and easily performed, and the functional and esthetic results are satisfactory.

Effect of time and ultrasonic activation on ethylenediaminetetraacetic acid on smear layer removal of the root canal.

The aim of this study was to assess the effect of time and the ultrasonic activation of ethylenediaminetetraacetic acid (EDTA) in removing the smear layer of at root canal. A total of 60 bovine inferior incisors were transversely sectioned and instrumented; A smear layer was added in the root dentin surface. The specimen were then divided into six groups according to the following final irrigation protocols: Group (G) 1: conventional irrigation with sodium hypochlorite (NaOCl); G2: conventional irrigation with NaOCl + EDTA for 20 s; G3: conventional irrigation with NaOCl + EDTA for 60 s; G4: passive ultrasonic irrigation (PUI) with NaOCl; G5: PUI with NaOCl + PUI with EDTA for 20 s; G6: PUI + NaOCl and PUI with EDTA for 60 s.

Clinical Comparison of At-Home and In-Office Dental Bleaching Procedures: A Randomized Trial of a Split-Mouth Design.

The objective of this split-mouth clinical study was to compare a combination of in-office and at-home dental bleaching with at-home bleaching alone. Two applications of in-office bleaching were performed, with one appointment per week, using 38% hydrogen peroxide. At-home bleaching was performed with or without in-office bleaching using 10% carbamide peroxide in a custom-made tray every night for 2 weeks.

Effect of partially demineralized dentin beneath the hybrid layer on dentin-adhesive interface micromechanics.

Objective: To investigate the presence of non-infiltrated, partially demineralized dentin (PDD) beneath the hybrid layer for self-etch adhesive systems, and its effect on micromechanical behavior of dentin-adhesive interfaces (DAIs). This in-vitro laboratory and computer simulation study hypothesized that the presence of non-infiltrated PDD beneath the hybrid layer does not influence the mechanical behavior of the DAI of self-etch adhesive systems.

Methods: Fifteen sound third molars were restored with composite resin using three adhesive systems: Scotchbond Multipurpose (SBMP), Clearfil SE Bond (CSEB) and Adper Promp L-Pop (APLP).

Effect of long-term storage on nanomechanical and morphological properties of dentin-adhesive interfaces.

Introduction: To evaluate the influence of storage time on the elastic modulus, micromorphology, nanoleakage, and micromechanical behavior of the dentin-adhesive interfaces of five adhesive systems (Scotchbond Multi-Purpose, Clearfil SE Bond, One Up Bond F, Adper Easy One, and Filtek LS Adhesive) after 24h (T0) and 12 months (T1).

Methods: Fifty teeth were restored and distributed according to each adhesive system (n=10). At least four specimens were obtained from each tooth.

Zirconia-based dental crown to support a removable partial denture: a three-dimensional finite element analysis using contact elements and micro-CT data.

Veneer fracture is the most common complication in zirconia-based restorations. The aim of this study was to evaluate the mechanical behavior of a zirconia-based crown in a lower canine tooth supporting removable partial denture (RPD) prosthesis, varying the bond quality of the veneer/coping interface. Microtomography (μCT) data of an extracted left lower canine were used to build the finite element model (M) varying the core material (gold core - MAu; zirconia core - MZi) and the quality of the veneer/core interface (complete bonded - MZi; incomplete bonded - MZi-NL).

Effect of abutment screw surface treatment on reliability of implant-supported crowns.

Purpose: To evaluate and compare the reliability of implant-supported single crowns cemented onto abutments retained with coated (C) or noncoated (NC) screws and onto platform-switched abutments with coated screws.

Materials And Methods: Fifty-four implants (DT Implant 4-mm Standard Platform, Intra-Lock International) were divided into three groups (n = 18 each) as follows: matching-platform abutments secured with noncoated abutment screws (MNC); matching-platform abutments tightened with coated abutment screws (MC); and switched-platform abutments secured with coated abutment screws (SC). Screws were characterized by scanning electron microscopy and x-ray photoelectron spectroscopy (XPS).

Stress distribution on dentin-cement-post interface varying root canal and glass fiber post diameters. A three-dimensional finite element analysis based on micro-CT data.

Objective: The aim of the present study was to analyze the influence of root canal and glass fiber post diameters on the biomechanical behavior of the dentin/cement/post interface of a root-filled tooth using 3D finite element analysis.

Material And Methods: Six models were built using micro-CT imaging data and SolidWorks 2007 software, varying the root canal (C) and the glass fiber post (P) diameters: C1P1-C=1 mm and P=1 mm; C2P1-C=2 mm and P=1 mm; C2P2-C=2 mm and P=2 mm; C3P1-C=3 mm and P=1 mm; C3P2-C=3 mm and P=2 mm; and C3P3-C=3 mm and P=3 mm. The numerical analysis was conducted with ANSYS Workbench 10.

Mineral loss and color change of enamel after bleaching and staining solutions combination.

Pigments of food and beverages could affect dental bleaching efficacy. The aim of this investigation was to evaluate color change and mineral loss of tooth enamel as well as the influence of staining solutions normally used by adolescent patients undergoing home bleaching. Initial hardness and baseline color were measured on enamel blocks.

Influence of platform and abutment angulation on peri-implant bone. A three-dimensional finite element stress analysis.

The aim of this study was to evaluate stress distribution on the peri-implant bone, simulating the influence of Nobel Select implants with straight or angulated abutments on regular and switching platform in the anterior maxilla, by means of 3-dimensional finite element analysis. Four mathematical models of a central incisor supported by external hexagon implant (13 mm × 5 mm) were created varying the platform (R, regular or S, switching) and the abutments (S, straight or A, angulated 15°). The models were created by using Mimics 13 and Solid Works 2010 software programs.

Periodontal ligament influence on the stress distribution in a removable partial denture supported by implant: a finite element analysis.

Objectives: The non-homogenous aspect of periodontal ligament (PDL) has been examined using finite element analysis (FEA) to better simulate PDL behavior. The aim of this study was to assess, by 2-D FEA, the influence of non-homogenous PDL on the stress distribution when the free-end saddle removable partial denture (RPD) is partially supported by an osseointegrated implant.

Material And Methods: Six finite element (FE) models of a partially edentulous mandible were created to represent two types of PDL (non-homogenous and homogenous) and two types of RPD (conventional RPD, supported by tooth and fibromucosa; and modified RPD, supported by tooth and implant [10.

Association of fixed partial denture and gingival prosthesis as alternative approach to recover esthetics and function in anterior maxillary region.

Tooth replacement in the maxillary anterior region is especially difficult when the loss includes significant amounts of the residual ridge and the soft tissue. Several techniques are available, such as dental implants or fixed partial denture, and bone and gingival grafts or gingival prostheses, respectively. This article showed a clinical case of an elderly who was treated with a collarless metal-ceramic fixed partial denture and acrylic removable gingival prosthesis to recover the esthetics in the maxillary anterior region.

Influence of microthreads and platform switching on stress distribution in bone using angled abutments.

Purpose: To evaluate the stress distribution in peri-implant bone by simulating the effect of an implant with microthreads and platform switching on angled abutments through tridimensional finite element analysis. The postulated hypothesis was that the presence of microthreads and platform switching would reduce the stress concentration in the cortical bone.

Methods: Four mathematical models of a central incisor supported by an implant (5.

Short implant to support maxillary restorations: bone stress analysis using regular and switching platform.

Purpose: The aim of this study was to evaluate stress distribution on peri-implant bone simulating the influence of implants with different lengths on regular and switching platforms in the anterior maxilla by means of three-dimensional finite element analysis.

Materials And Methods: Four mathematical models of a central incisor supported by an external hexagon implant (diameter, 5.0 mm) were created, varying the length (15.

Straight and angulated abutments in platform switching: influence of loading on bone stress by three-dimensional finite element analysis.

Purpose: In view of reports in the literature on the benefits achieved with the use of platform switching, described as the use of an implant with a larger diameter than the abutment diameter, the goal being to prevent the (previously) normal bone loss down to the first thread that occurs around most implants, thus enhancing soft tissue aesthetics and stability and the need for implant inclination due to bone anatomy in some cases, the aim of this study was to evaluate bone stress distribution on peri-implant bone, by using three-dimensional finite element analysis to simulate the influence of implants with different abutment angulations (0 and 15 degrees) in platform switching.

Methods: Four mathematical models of an implant-supported central incisor were created with varying abutment angulations: straight abutment (S1 and S2) and angulated abutment at 15 degrees (A1 and A2), submitted to 2 loading conditions (100 N): S1 and A1-oblique loading (45 degrees) and S2 and A2-axial loading, parallel to the long axis of the implant. Maximum (σmax) and minimum (σmin) principal stress values were obtained for cortical and trabecular bone.

Influence of crown ferrule heights and dowel material selection on the mechanical behavior of root-filled teeth: a finite element analysis.

Purpose: This study used the 3D finite element (FE) method to evaluate the mechanical behavior of a maxillary central incisor with three types of dowels with variable heights of the remaining crown structure, namely 0, 1, and 2 mm.

Materials And Methods: Based on computed microtomography, nine models of a maxillary central incisor restored with complete ceramic crowns were obtained, with three ferrule heights (0, 1, and 2 mm) and three types of dowels (glass fiber = GFD; nickel-chromium = NiCr; gold alloy = Au), as follows: GFD0--restored with GFD with absence (0 mm) of ferrule; GFD1--similar, with 1 mm ferrule; GFD2--glass fiber with 2 mm ferrule; NiCr0--restored with NiCr alloy dowel with absence (0 mm) of ferrule; NiCr1--similar, with 1 mm ferrule; NiCr2--similar, with 2 mm ferrule; Au0--restored with Au alloy dowel with absence (0 mm) of ferrule; Au1--similar, with 1 mm ferrule; Au2--similar, with 2 mm ferrule. A 180 N distributed load was applied to the lingual aspect of the tooth, at 45° to the tooth long axis.

Regular and platform switching: bone stress analysis varying implant type.

Purpose: This study aimed to evaluate stress distribution on peri-implant bone simulating the influence of platform switching in external and internal hexagon implants using three-dimensional finite element analysis.

Materials And Methods: Four mathematical models of a central incisor supported by an implant were created: External Regular model (ER) with 5.0 mm × 11.

Prosthetic platforms in implant dentistry.

The use of implant-supported prosthesis to replace missing teeth became a predictable treatment. Although high success rate has been reported, implant treatment is suitable to complications, failures, and limitations such as peri-implant bone loss after implant loading. Stress evaluation on the bone-abutment-implant interface has been carried out to develop new designs of prosthetic platform and to understand the stress distribution in this interface.

Bonding all-ceramic restorations with two resins cement techniques: a clinical report of three-year follow-up.

Ceramics have been widely used for esthetic and functional improvements. The resin cement is the material of choice for bonding ceramics to dental substrate and it can also dictate the final esthetic appearance and strength of the restoration. The correct use of the wide spectrum of resin luting agents available depends on the dental tooth substrate.

Influence of buccal cusp reduction when using porcelain laminate veneers in premolars. A comparative study using 3-D finite element analysis.

Objectives: Based on a maxillary premolar restored with laminate veneer and using the 3-D finite element analysis (FEA) and μCT data, the aim of this study was to evaluate the influence of different types of buccal cusp reduction on the stress distribution in the porcelain laminate veneer and in the resin luting cement layer.

Methods: Two 3-D FEA models (M) of a maxillary premolar were built from μCT data. The buccal cusp reduction followed two configurations: Mt - buccal cusp completely covered by porcelain laminate veneer; and Mp - buccal cusp partially covered by porcelain laminate veneer.