A novel algorithmic approach for automatic virtual articulation to avoid dynamic interferences in dental restoration designs.

Aim: There is an ongoing debate about the benefits of the facebow and individual articulator settings in prosthodontics when compared with simpler methods. The present study aims to determine whether the implementation of novel algorithmic articulator concepts may be an alternative to avoid dynamic interference contacts during the design process of fixed posterior restorations, and to what extent the occlusal morphology of the restoration is affected.

Materials And Methods: From a chairside CAD database, a total of 50 clinical patient cases documenting 61 planned fixed restorations in the posterior tooth region were selected.

Notch Signaling Pathway in Tooth Shape Variations throughout Evolution.

Evolutionary changes in vertebrates are linked to genetic alterations that often affect tooth crown shape, which is a criterion of speciation events. The Notch pathway is highly conserved between species and controls morphogenetic processes in most developing organs, including teeth. Epithelial loss of the Notch-ligand Jagged1 in developing mouse molars affects the location, size and interconnections of their cusps that lead to minor tooth crown shape modifications convergent to those observed along Muridae evolution.

Randomized controlled pilot study assessing efficacy, efficiency, and patient-reported outcomes measures of chairside and labside single-tooth restorations.

Objectives: To test whether or not a chairside workflow (CHAIR) is similar to a labside workflow (LAB) in terms of efficacy (primary outcome) and efficiency (secondary outcome).

Material And Methods: Eighteen subjects in need of a single-tooth restoration in the posterior region of the maxilla or mandible were consecutively recruited and randomly assigned to the CHAIR or LAB workflow. Patient-reported outcome measures (PROMs; efficacy) were assessed using a questionnaire with visual analog scale.

Accuracy, trueness, and precision - a guideline for the evaluation of these basic values in digital dentistry.

An increasing number of accuracy studies on 3D digitizing systems, especially intraoral scanning devices, are being published in scientific and educational journals. The methods, measurement values, and statistical parameters of these studies vary. Certain inconsistencies exist, which lead to difficulty in terms of interpretation and sometimes even questionable conclusions being drawn.

Time Efficiency of Digitally and Conventionally Produced Single-Unit Restorations.

The purpose of this in vitro study was to compare the time efficiency of digital chairside and labside workflows with a conventional workflow for single-unit restorations. The time efficiency in this specific sense was defined as the time, which has to be spent in a dental office by a dental professional performing the relevant steps. A model with interchangeable teeth on position 36 was created.

Effects of overnight storage conditions on conventional complete removable prostheses.

Purpose: To evaluate the effects of overnight storage conditions on the dimensional stability and retention of prostheses, as well as the participant's subjective perception of these interventions.

Materials And Methods: Subjects with maxillary complete prostheses (CRPs) were randomly assigned to receive two interventions in a crossover design: storing the CRPs overnight in a dry or wet environment with a cleansing tablet. The denture intaglio surface was scanned, and outcome measures were collected before each intervention (BLN), post ntervention (PIS), and after immersion in water for 15 minutes after the intervention (WOC).

Accuracy of digital complete-arch, multi-implant scans made in the edentulous jaw with gingival movement simulation: An in vitro study.

Statement Of Problem: The use of computer-aided design and computer-aided manufacturing (CAD-CAM) technologies is widely established, with single restorations or short fixed partial dentures having similar accuracy when generated from digital scans or conventional impressions. However, research on complete-arch scanning of edentulous jaws is sparse.

Purpose: The purpose of this pilot in vitro study was to compare the accuracy of a digital scan with the conventional method in a workflow generating implant-supported complete-arch prostheses and to establish whether interference from flexible soft tissue segments affects accuracy.

Low-Profile Electromagnetic Field Sensors in the Measurement and Modelling of Three-Dimensional Jaw Kinematics and Occlusal Loading.

Dynamic occlusal loading during mastication is clinically relevant in the design and functional assessment of dental restorations and removable dentures, and in evaluating temporomandibular joint dysfunction. The aim of this study was to develop a modelling framework to evaluate subject-specific dynamic occlusal loading during chewing and biting over the entire dental arch. Measurements of jaw motion were performed on one healthy male adult using low-profile electromagnetic field sensors attached to the teeth, and occlusal anatomy quantified using an intra-oral scanner.

Measurement of normal and pathological mandibular and temporomandibular joint kinematics: A systematic review.

Motion of the mandible and temporomandibular joint (TMJ) plays a pivotal role in the function of the dentition and associated hard and soft tissue structures, and facilitates mastication, oral communication and access to respiratory and digestive systems. Quantification of TMJ kinematics is clinically relevant in cases of prosthetic rehabilitations, TMJ disorders, osteoarthritis, trauma, tumour resection and congenital abnormalities, which are known to directly influence mandibular motion and loading. The objective of this systematic review was to critically investigate published literature on historic and contemporary measurement modalities used to quantify in vivo mandibular and TMJ kinematics in six degrees of freedom.

Fracture Load of CAD/CAM Feldspathic Crowns Influenced by Abutment Material.

In vitro studies investigating the mechanical properties of dental reconstructions use various materials to replicate prepared teeth. However, no uniform recommendation exists as to which material is most suitable for standardized testing. The purpose of this study was to identify a material that resembles human dentin in fracture load tests.

Is it possible to detect a true rotation axis of the temporomandibular joint with common pantographic methods? A fundamental kinematic analysis.

The location of the terminal hinge axis of the temporomandibular joint is still a very wide-spread procedure in dentistry in order to replicate the movement in various articulator devices. Especially pantographic methods are claimed to provide accurate measurements and, additionally, are seen to be able to separate a pure rotation of the joint from a movement with an arbitrary combined shift and rotation. In the latter application, these methods were used in a lot of studies as a reference standard.

Local accuracy of actual intraoral scanning systems for single-tooth preparations in vitro.

Background: The authors evaluated the local accuracy of intraoral scanning (IOS) systems for single-tooth preparation impressions with an in vitro setup.

Methods: The authors digitized a mandibular complete-arch model with 2 full-contour crowns and 2 multisurface inlay preparations with a highly accurate reference scanner. Teeth were made from zirconia-reinforced glass ceramic material to simulate toothlike optical behavior.

Teaching dental undergraduate students restorative CAD/CAM technology: evaluation of a new concept.

Objectives: The use of computer-aided design/computer-aided manufacturing (CAD/CAM) technology in restorative dentistry has increased significantly and should consequently be taught more intensively at university dental schools. This study describes the evaluation of a new CAD/CAM teaching concept.

Methods: CAD/CAM technology was implemented into a 4th-year clinical student course according to Miller's pyramid principle.

Fracture load of three-unit full-contour fixed dental prostheses fabricated with subtractive and additive CAD/CAM technology.

Objectives: The aim of this study was to test the fracture load of ceramic and composite three-unit full-contour fixed dental prostheses (FDPs) fabricated with additive and subtractive computer-aided design (CAD)/computer-aided manufacturing (CAM) technology.

Materials And Methods: A newly developed alveolar socket replica model for a three-unit FDP replacing one molar was used in this study. Five CAD/CAM materials were used for fabrication of three-unit FDPs (each n = 12).

Accuracy of complete- and partial-arch impressions of actual intraoral scanning systems in vitro.

Objective: Intraoral scanners (IOSs) are widely used for obtaining digital dental models directly from the patient. Additionally, improvements in IOSs are made from generation to generation. The aim of this study was to evaluate the accuracy of new and actual IOS devices for complete- and partial-arch dental impressions in an in vitro setup.

CAD-CAM milled versus rapidly prototyped (3D-printed) complete dentures: An in vitro evaluation of trueness.

Statement Of Problem: Complete dentures fabricated by computer-aided design and computer-aided manufacturing (CAD-CAM) techniques have become popular. The 2 principal CAD-CAM techniques, milling and rapid prototyping (3D printing), used in the fabrication of complete dentures have been reported to yield clinically acceptable results. However, clinical trials or in vitro studies that evaluated the accuracy of the 2 manufacturing techniques are lacking.

Hinge axis determination of the temporomandibular joint and its interpretation: what do we really measure?

Terminal hinge axis (THA) determination is recommended in some clinical situations and for some diagnostic purposes. Different methods are described and are available for this task. In particular, circle fitting or iterative trace recording methods, in the conventional process known as the pantographic or Lauritzen method, have mostly been applied in clinical settings and have even been used as exact reference measures in many studies.

Fracture load of CAD/CAM-fabricated and 3D-printed composite crowns as a function of material thickness.

Objectives: Indirect CAD/CAM restorations can be fabricated using both subtractive and additive CAD/CAM technology. This study investigated the fracture load of crowns fabricated from three particle-filled composite CAD/CAM materials and one 3D-printed composite material.

Materials And Methods: Lava Ultimate, Cerasmart and Brilliant Crios were used as particle-filled composite CAD/CAM material and els-3D Harz as 3D-printed composite material.

The determination of the terminal hinge axis: a fundamental review and comparison of known and novel methods.

Different concepts are used for the analysis and transfer of mandibular movements to virtual or conventional articulating systems. Some common procedures and analyses include the determination of the terminal hinge axis. However, despite the widespread use of different methods for hinge axis determination, very little information on the applicability and quality of these methods is currently available in the literature.

Three-Dimensional Digital Evaluation of the Fit of Endocrowns Fabricated from Different CAD/CAM Materials.

Purpose: A wide variety of CAD/CAM materials are available for single-tooth restorations. CAD/CAM material characteristics are different and may influence CAM fabrication accuracy. There is no study investigating the influence of different CAD/CAM materials on the final fit of the restoration.

In vivo tooth-color measurement with a new 3D intraoral scanning system in comparison to conventional digital and visual color determination methods.

Statement Of Problem: Three-dimensional (3D) intraoral scanning systems allow for the simultaneous acquisition of 3D information about tooth surfaces and a photorealistic view of the patient's tooth colors.

Aim: The goal of this study was the in vivo comparison of a new 3D scanner with a color acquisition mode and conventional visual and digital color measurements.

Materials And Methods: The colors of 40 teeth of 20 patients were evaluated in seven ways: 1) By dentists using the Vita 3D-Master; 2) By dental technicians using the Vita 3D-Master; 3) With the 3Shape Trios device; 4) With the Vita Easyshade device; 5) With the Vita Easyshade Advance device; 6) With the SpectroShade device; and 7) With the SpectroShade Micro device.

Digital evaluation of the fit of zirconia-reinforced lithium silicate crowns with a new three-dimensional approach.

Objective: Several methods for the evaluation of fit of computer-aided design/computer-assisted manufacture (CAD/CAM)-fabricated restorations have been described. In the study, digital models were recorded with an intraoral scanning device and were measured using a new three-dimensional (3D) computer technique to evaluate restoration internal fit. The aim of the study was to evaluate the internal adaptation and fit of chairside CAD/CAM-fabricated zirconia-reinforced lithium silicate ceramic crowns fabricated with different post-milling protocols.

Influence of material thickness on fractural strength of CAD/CAM fabricated ceramic crowns.

The fracture behavior of CAD/CAM fabricated crowns was investigated as a function of material thickness for six silicate ceramic materials: Mark II, e.max CAD, Celtra Duo milled, Celtra Duo fired, Suprinity, Enamic. Crowns with thicknesses 0.