The influence of customization of glass fiber posts on fracture strength and failure pattern: A systematic review and meta-analysis of preclinical ex-vivo studies.

Objective: To perform a systematic review of the literature focused to evaluate in vitro function of prefabricated fiber posts with and without customization by additional auxillary fiber posts and composite resin on the fracture strength of wide or enlarged canals and the failure pattern.

Methods: Six databases were used as primary search sources (PubMed, Scopus, LILACS, SciELO, Science Direct, and Web of Science) and three databases (Open Grey, Open Thesis, and OATD) were used to partially capture the "grey literature". The research included laboratory studies that used human upper anterior teeth aiming to assess the fracture strength and failure pattern of different glass fiber post customizations by additional auxiliary fiber posts or composite resin.

The Use of Bulk-Fill Flow in the Customization of Glass Fiber Post.

Objectives:  The aim of this study is to evaluate the influence of different composite resin in the customization of glass fiber posts (GFPs) on bond strength and failure mode.

Materials And Methods:  Thirty bovine roots were selected. The wall roots were reduced so that each wall had a minimum dentin thickness of 1 mm.

How biomechanics can affect the endodontic treated teeth and their restorative procedures?

Endodontic treatment is a common dental procedure used for treating teeth which the pulp tissue has become irreversibly inflamed or necrotic as a result of the carious process or dental trauma. This procedure which involves mechanical and chemical preparation of root canal may affect several mechanical and physical properties of the tooth structure. The endodontic treatment can also influence the longevity of the rehabilitation of endodontically treated teeth and biomechanics during the oral function.

Comparative evaluation of 3 microbond strength tests using 4 adhesive systems: Mechanical, finite element, and failure analysis.

Statement Of Problem: Bond strength (BS) values from in vitro studies are useful when dentists are selecting an adhesive system, but there is no ideal measuring method.

Purpose: The purpose of this in vitro study was to investigate the influence of the evaluation method in the BS between dentin and composite resin.

Material And Methods: Molars with exposed superficial dentin (N=240) were divided into 3 groups according to the test: microtensile (μTBS), microshear (μSBS), and micropush-out (μPBS).

External Hexagon Deformation in Implants Subjected to Internal Torque.

Failures may occur in the connections of dental implants, especially in external hexagon (EH). Due to the deformations in this portion of implants, this study aimed to evaluate the levels of deformation of EH connections subjected to internal toque. Two types of implants were used: N group and S group.

Custom-Fitted EVA Mouthguards: what is the ideal thickness? a dynamic finite element impact study.

Background/aim: The aim of this study was to evaluate the tooth stresses and strains, shock absorption, and displacement during impact of custom-fitted mouthguards with different thicknesses.

Methods: Six bar-shaped specimens of the EVA were made and subjected to tensile test for elastic modulus assessment. Two-dimensional plane-strain models of a human maxillary central incisor, periodontal ligament, bone support, soft tissue, and mouthguard (MTG) were created.

Evaluation of a dentoalveolar model for testing mouthguards: stress and strain analyses.

Background/aim: Custom-fitted mouthguards are devices used to decrease the likelihood of dental trauma. The aim of this study was to develop an experimental bovine dentoalveolar model with periodontal ligament to evaluate mouthguard shock absorption, and impact strain and stress behavior.

Methods: A pendulum impact device was developed to perform the impact tests with two different impact materials (steel ball and baseball).

Modifying the biomechanical response of mouthguards with hard inserts: A finite element study.

Purpose: To investigate the influence of a high elastic modulus material insert on the stress, shock absorption and displacement of mouthguards.

Methods: Finite element models of a human maxillary central incisor with and without mouthguard were created based on cross-sectional CT-tomography. The mouthguard models had four designs: without insert, and middle, external, or palatal hard insert.

Does the moment of fiber post cutting influence on the retention to root dentin?

Despite several advantages associated with pre-fabricated glass-fiber posts, the coronal portion of these posts must be cut to allow their use in various clinical situations. However, cutting the cemented post can generate stress on the bonding interface and affect the bond strength. The aim of this study was to investigate the effect the of fiber post cutting on the bond strength of root canals.

Influence of ferrule, post system, and length on stress distribution of weakened root-filled teeth.

Introduction: The aim of this study was to evaluate the influence of a ferrule, post system, and length on the stress distribution of weakened root-filled teeth.

Methods: The investigation was conducted by using 3-dimensional (3D) finite element analysis. A sound tooth and 8 3D models of a weakened root-filled central incisor were generated using computer-aided design/computer-aided manufacturing software.

Influence of ferrule, post system, and length on biomechanical behavior of endodontically treated anterior teeth.

Introduction: The aim of this study was to evaluate the influence of post system, length, and ferrule on biomechanical behavior of endodontically treated anterior teeth.

Methods: The investigation was conducted by using laboratory tests and 3-dimensional finite element analysis. Eighty bovine incisors were selected and divided into 8 treatment groups (n = 10) with absence of ferrule and 2.

Effect of the crown, post, and remaining coronal dentin on the biomechanical behavior of endodontically treated maxillary central incisors.

Statement Of Problem: It is unclear how the amount of remaining coronal dentin and the type of post and core rehabilitation affect the strain, stress distribution, and fracture resistance of endodontically treated teeth.

Purpose: The purpose of this study was to evaluate the effects of the type of post, type of crown, and the amount of remaining coronal dentin on the biomechanical behavior of endodontically treated teeth.

Material And Methods: The investigation was conducted by using 3-dimensional finite element analysis and laboratory tests.

Can the cure time of endodontic sealers affect bond strength to root dentin?

The cure time of endodontic sealers may influence the bond strength of fiber posts to root dentin. Forty teeth were selected and endodontically filled using calcium hydroxide cement and then divided into 2 groups according to the time elapsed between endodontic filling and post luting (n = 20): Immediately - glass fiber post luting immediately after endodontic filling; and Delayed - post luting performed 7 days after endodontic filling. The roots were also subdivided according to resin cement used for post luting (RelyX ARC and RelyX Unicem).

Effects of threaded post placement on strain and stress distribution of endodontically treated teeth.

The aim of this study was to evaluate the effect of parallel and tapered threaded post placement on the strain and stress distribution of endodontically treated teeth. Fifteen bovine incisors were sectioned 15 mm from their apices, endodontically treated, and divided into three groups (n=5) according to three different threaded posts: parallel threaded post (Radix-Anker, RA); tapered threaded post (Euro-Post, EP) and tapered threaded post (Reforpost II, RII). A strain-gauge was fixed on the proximal surface perpendicular to the long root axis, 2 mm from the cervical limit.

Does bonding to dentin reduce microleakage of composite restorations?

This study evaluated the effect of adhesive application only to enamel on the marginal microleakage of composite resin restorations performed with different adhesive systems. Standardized cylinder-shaped cavities were prepared on the buccal surface of eighty bovine incisors. Two etch-and-rinse (Adper Scotchbond Multi-purpose [3M ESPE, St.

In vitro study of fracture load and fracture pattern of ceramic crowns: a finite element and fractography analysis.

Purpose: This in vitro study investigated the null hypothesis that metal-free crowns induce fracture loads and mechanical behavior similar to metal ceramic systems and to study the fracture pattern of ceramic crowns under compressive loads using finite element and fractography analyses.

Materials And Methods: Six groups (n = 8) with crowns from different systems were compared: conventional metal ceramic (Noritake) (CMC); modified metal ceramic (Noritake) (MMC); lithium disilicate-reinforced ceramic (IPS Empress II) (EMP); leucite-reinforced ceramic (Cergogold) (CERG); leucite fluoride-apatite reinforced ceramic (IPS d.Sign) (SIGN); and polymer crowns (Targis) (TARG).

Effect of periodontal therapies on indirect restoration: a scanning electron microscopic analysis.

The aim of this study was to evaluate the influence of different periodontal therapies on the integrity of indirect restorations by scanning electron microscopy (SEM). Sixty single-rooted bovine teeth were selected and randomly assigned to 12 groups. Inlay cavities were prepared in the cervical region on the center of the cementoenamel junction, and were restored with laboratory processed resin and luted with a resin cement.

Effect of different cements on the biomechanical behavior of teeth restored with cast dowel-and-cores-in vitro and FEA analysis.

Purpose: To test the hypothesis that the type of cement used for fixation of cast dowel-and-cores might influence fracture resistance, fracture mode, and stress distribution of single-rooted teeth restored with this class of metallic dowels.

Materials And Methods: The coronal portion was removed from 40 bovine incisors, leaving a 15 mm root. After endodontic treatment and standardized root canal relief at 10 mm, specimens were embedded in polystyrene resin, and the periodontal ligament was simulated with polyether impression material.

Bond Strength of One-Step Adhesives under Different Substrate Moisture Conditions.

Objectives: The aim of this study was to evaluate the bond strength of one-step adhesive systems to dry or moist dental substrate.

Methods: Thirty human third molars were sectioned into two halves, in the mesio-distal direction, parallel to the long axis of the tooth. Each half was embedded in a polystyrene resin cylinder so that the buccal/lingual surface remained exposed.

Influence of different post design and composition on stress distribution in maxillary central incisor: Finite element analysis.

Background: Post design and material has very important effects on dentinal stress distribution since the post placement can create stresses that lead to root fracture.

Materials And Methods: In this study we use finite element analysis (FEA) to evaluate stress distribution on endodontically treated maxillary central incisors that have been restored with different prefabricated posts. Six models were generated from the image of anatomical plate: Four metallic posts (ParaPost XH, ParaPost XT, ParaPost XP, and Flexi-Flange) and one fiberglass post (ParaPost Fiber Lux).

Two-dimensional FEA of dowels of different compositions and external surface configurations.

Purpose: The degree of stress generated in the endodontically treated and restored tooth can be influenced by the composition and configuration of the dowels used for the restoration. Using two-dimensional (2D) finite element analysis (FEA), this study tested the hypothesis that the characterization of the stress distribution can be influenced by which evaluation method is employed: protrusion loading and 4-point flexural strength test or varying the type of material (carbon and glass fiber) or the external configuration of the dowel (smooth and serrated).

Materials And Methods: For simulation of the protrusion load test, models were generated with Mechanical-AutoCAD V6 software from an image of an anatomical plate, one maxillary central incisor, and two dowels and exported to Ansys 9.

Finite element analysis and bond strength of a glass post to intraradicular dentin: comparison between microtensile and push-out tests.

Objective: This study tested the hypothesis that the stress distribution and bond strength of glass posts to intraradicular dentin is influenced by the mechanical testing methodology.

Methods: Thirty single rooted endodontically treated teeth were prepared for luting of tapered fiber-glass posts (Reforpost, Angelus, Londrina, PR, Brazil) with a conventional adhesive system and resin luting cement (Adper Scotchbond Multi-purpose, Rely X ARC, 3M ESPE, St. Paul, MN, USA).

Influence of restorative technique on the biomechanical behavior of endodontically treated maxillary premolars. Part II: strain measurement and stress distribution.

Statement Of Problem: Unresolved controversy exists concerning the preferred cavity design and restorative technique used to restore endodontically treated maxillary premolars to minimize strain and improve stress distribution under occlusal load.

Purpose: The purpose of this study was to analyze the influence of cavity design and restorative material on strain measurement and stress distribution in maxillary premolars under occlusal loading conditions, and correlate these influences with the failure modes analyzed in Part I.

Material And Methods: For the strain gauge test, 21 additional specimens were prepared as described in Part 1 of this study (n=3).

Influence of restorative technique on the biomechanical behavior of endodontically treated maxillary premolars. Part I: fracture resistance and fracture mode.

Statement Of Problem: Unresolved controversy exists concerning the preferred cavity design and restorative technique used to restore endodontically treated maxillary premolars to improve their resistance to fracture under occlusal load.

Purpose: The purpose of this study was to evaluate the fracture resistance, stress distribution, and cusp deformation of endodontically treated human maxillary premolars restored with different materials. The study is divided into 2 parts.