Search

Objectives: The purposes of this study were to classify the described digital facebow techniques for transferring the maxillary cast into the semi‐adjustable virtual articulator based on the digital data acquisition technology used and to review the reported accuracy values of the different digital facebow methods described. Overview: Digital data acquisition technologies, including digital photographs, facial scanners, cone beam computed tomography (CBCT) imaging, and jaw tracking systems, can be used to transfer the maxillary cast into the virtual articulator. The reported techniques are reviewed, as well as the reported accuracy values of the different digital facebow methods. Conclusions: Digital photographs can be used to transfer the maxillary cast into the virtual articulator using the true horizontal reference plane, but limited studies have assessed the accuracy of this method. Facial scanning and CBCT techniques can be used to transfer the maxillary cast into the virtual articulator, in which the most frequently selected references planes are the Frankfort horizontal, axis orbital, and true horizontal planes. Studies analyzing the accuracy of the maxillary cast transfer by using facial scanning and CBCT techniques are restricted. Lastly, optical jaw trackers can be selected for transferring the maxillary cast into the virtual articulator by using the axis orbital or true horizontal planes, yet the accuracy of these systems is unknown. Clinical Implications: Digital data acquisition technologies, including digital photographs, facial scanning methods, CBCTs, and optical jaw tracking systems, can be used to transfer the maxillary cast into the virtual articulator. Studies are needed to assess the accuracy of these digital data acquisition technologies for transferring the maxillary cast into the virtual articulator. [ABSTRACT FROM AUTHOR]

Objectives: To provide an overview of the current artificial intelligence (AI) based applications for assisting digital data acquisition and implant planning procedures. Overview: A review of the main AI‐based applications integrated into digital data acquisitions technologies (facial scanners (FS), intraoral scanners (IOSs), cone beam computed tomography (CBCT) devices, and jaw trackers) and computer‐aided static implant planning programs are provided. Conclusions: The main AI‐based application integrated in some FS's programs involves the automatic alignment of facial and intraoral scans for virtual patient integration. The AI‐based applications integrated into IOSs programs include scan cleaning, assist scanning, and automatic alignment between the implant scan body with its corresponding CAD object while scanning. The more frequently AI‐based applications integrated into the programs of CBCT units involve positioning assistant, noise and artifacts reduction, structures identification and segmentation, airway analysis, and alignment of facial, intraoral, and CBCT scans. Some computer‐aided static implant planning programs include patient's digital files, identification, labeling, and segmentation of anatomical structures, mandibular nerve tracing, automatic implant placement, and surgical implant guide design. [ABSTRACT FROM AUTHOR]

ABSTRACT Objectives Overview Conclusions Clinical Implications To review the factors that impact the accuracy of intraoral scanners (IOSs) when fabricating tooth‐supported restorations.Factors can have a different impact on IOS accuracy depending on the scanning purpose. If the goal is to fabricate tooth‐supported restorations, it is essential to review the following operator‐related factors: IOS technology and system, scan extension and starting quadrant, scanning pattern, scanning distance, and rescanning methods. Additionally, it is critical to interpret the following patient‐related factors differently: edentulous spaces, presence of existing restorations on adjacent teeth, and characteristics of the tooth preparation (build‐up material, geometry, total occlusal convergence [TOC], finish line location, and surface finishing), and interdental spaces (between tooth preparations or between preparation and the adjacent tooth).For crown or short‐span fixed dental prostheses, a reduced scan extension is recommended. For complete‐arch scans, it is advisable to start the scan in the same quadrant as the preparation. If the IOS permits locking the scan, rescanning may be indicated. Restorations on tooth preparations and adjacent teeth reduce accuracy. The simpler the geometry and the larger the TOC, the higher the IOS accuracy. Intracrevicular finish lines result in lower accuracy than equigingival or supragingival positions. Air‐particle procedures showed better accuracy than coarse and fine grit and immediate dentin sealing. The greater the space between a preparation and the adjacent tooth, the better the accuracy.Dental professionals must understand and handle the factors that impact the scanning accuracy of intraoral scanners differently depending on the purpose of the scan. [ABSTRACT FROM AUTHOR]

The reverse impression method involves the extraoral digitalization of the interim implant‐supported prostheses and intraoral digitalization of antagonist arch and maxillomandibular relationship. This technique allows the fabrication of implant‐supported prostheses by using a complete‐digital workflow. The scan analogs make the reverse impression method feasible. However, this method may not be recommended if the interim polymethyl methacrylate prosthesis does not have passive fit. The present manuscript describes an altered reverse impression technique that involves the extraoral digitalization of a conventional verification jig, which has attached scan analogs. With this technique modification, the implant positions captured using the verification jig are used to obtain the virtual definitive implant cast and fabricate the definitive implant‐supported prosthesis. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of the present clinical study was to compare the Ricketts and Steiner cephalometric analysis obtained by two experienced orthodontists and artificial intelligence (AI)‐based software program and measure the orthodontist variability. Materials and Methods: A total of 50 lateral cephalometric radiographs from 50 patients were obtained. Two groups were created depending on the operator performing the cephalometric analysis: orthodontists (Orthod group) and an AI software program (AI group). In the Orthod group, two independent experienced orthodontists performed the measurements by performing a manual identification of the cephalometric landmarks and a software program (NemoCeph; Nemotec) to calculate the measurements. In the AI group, an AI software program (CephX; ORCA Dental AI) was selected for both the automatic landmark identification and cephalometric measurements. The Ricketts and Steiner cephalometric analyses were assessed in both groups including a total of 24 measurements. The Shapiro–Wilk test showed that the data was normally distributed. The t‐test was used to analyze the data (α = 0.05). Results: The t‐test analysis showed significant measurement discrepancies between the Orthod and AI group in seven of the 24 cephalometric parameters tested, namely the corpus length (p = 0.003), mandibular arc (p < 0.001), lower face height (p = 0.005), overjet (p = 0.019), and overbite (p = 0.022) in the Ricketts cephalometric analysis and occlusal to SN (p = 0.002) and GoGn‐SN (p < 0.001) in the Steiner cephalometric analysis. The intraclass correlation coefficient (ICC) between both orthodontists of the Orthod group for each cephalometric measurement was calculated. Conclusions: Significant discrepancies were found in seven of the 24 cephalometric measurements tested between the orthodontists and the AI‐based program assessed. The intra‐operator reliability analysis showed reproducible measurements between both orthodontists, except for the corpus length measurement. Clinical Significance: The artificial intelligence software program tested has the potential to automatically obtain cephalometric analysis using lateral cephalometric radiographs; however, additional studies are needed to further evaluate the accuracy of this AI‐based system. [ABSTRACT FROM AUTHOR]

Objectives: To describe a new classification for intraoral scans based on the scan extension and to introduce a decision guideline to choose the scan extension for fabricating tooth‐ and implant‐supported fixed dental prostheses (FDPs). Overview: Multiple operator‐ and patient‐related factors have been identified that can decrease the scanning accuracy of intraoral scanners (IOSs), including scan extension. However, the decision criteria for selecting scan extension for fabricating tooth‐ and implant‐supported restorations is unclear. Based on the extension of the intraoral digital scans, three types of scans can be defined: half‐arch (anterior or posterior), extended half‐arch, and complete‐arch scan. Variables to consider when choosing the scan extension include the number and location of units being restored, as well as the extension and location of edentulous areas. Additionally, the accuracy of the virtual definitive cast and the accuracy of the maxillomandibular relationship captured by using IOSs should be differentiated. Conclusions: A decision tree for selecting the scan extension is presented. The decision is based on the number and location of units being restored, and the extension and location of edentulous areas. Intraoral scans with reduced scan extension are indicated when fabricating tooth‐ and implant‐supported crowns or short‐span fixed prostheses, when the patient does not have more than one missing tooth in the area of the dental arch included in the scan. For the remaining clinical conditions, complete‐arch intraoral scans are recommended. Clinical Significance: Scan extension is a clinician's decision that should be based on the number and location of units being restored and the extension and location of edentulous areas. Intraoral scans with a reduced scan extension is recommended, when possible. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate accuracy, scanning time, and patient satisfaction of photogrammetry (PG) systems for recording the 3D position of dental implants. Material and Methods: A literature search was completed in five databases: PubMed/Medline, Scopus, Embase, World of Science, and Cochrane. A manual search was also conducted. Studies reporting the use of commercially available PG systems were included. Two investigators evaluated the studies independently by applying the Joanna Briggs Institute critical appraisal. A third examiner was consulted to resolve any lack of consensus. Results: A total of 14 articles were included: 3 in vivo, 6 in vitro, and 6 case report manuscripts. One clinical study evaluated trueness, another one tested precision, and the third one assessed impression time and patient and operator satisfaction. All the in vitro studies evaluated the trueness and precision of a PG system. Additionally, all the reviewed studies investigated completely edentulous conditions with multiple implants. The number of placed implants per arch among the reviewed clinical studies varied from 4 to 8 implants, while the number of implants placed on the reference casts included 4, 5, 6, or 8 implants. Not all the studies compared the accuracy of PG systems with conventional impression methods, using intraoral scanners as additional experimental groups. For the PIC system, trueness ranged from 10 to 49 μm and precision ranged from 5 to 65 μm. For the iCam4D system, trueness ranged from 24 to 77 μm and the precision value ranged from 2 to 203 μm. Conclusions: PG systems may provide a reliable alternative for acquiring the 3D position of dental implants. However, this conclusion should be interpreted carefully, as one study reported a mean precision value of one PG system higher than the clinically acceptable discrepancy. Lower scanning time and higher patient and operator satisfaction have been reported when compared with conventional techniques. Further studies are needed to increase the evidence regarding the accuracy, scanning time, and patient and operator satisfaction of the commercially available PG systems. [ABSTRACT FROM AUTHOR]

Dental literature has reported greater intraoral scanning accuracy when implant scan bodies (ISBs) are connected compared with non‐connected methods. Initial intraoral digital implant scans are required for the fabrication of a custom framework to connect implant scan bodies (IOSFix; IOSFix Dental). This calibrated metal framework is used to acquire definitive intraoral implant scans. However, the acquisition of initial intraoral implant scans can be challenging when ISBs are not connected. This article describes a step‐by‐step technique for connecting ISBs by using additively manufactured devices to acquire initial intraoral implant scans. This technique aims to facilitate the recording of initial intraoral implant scans, provide different device designs and sizes to connect ISBs, and reduce chairside time. [ABSTRACT FROM AUTHOR]

Purpose: To report the means to maximize the predictability and accuracy of intraoral digital implant scans through the evaluation of operator and patient‐related factors. Materials and Methods: A search of published articles related to factors that can decrease the scanning accuracy of intraoral digital implant scans was completed in four data sources:MEDLINE, EMBASE, EBSCO, and Web of Science. All studies related to variables that can influence the accuracy of intraoral digital implant scans obtained by using intraoral scanners (IOSs) were considered. These variables included ambient lighting, scanning pattern, implant scan body (ISB) design, techniques for splinting ISBs, arch location, implant position, and inter‐implant distance. Results: Among operator‐related factors, ambient lighting conditions, scanning pattern, and ISB design (material, geometry, and retention design) can impact the accuracy of intraoral digital implant scans. The optimal ISB for maximizing IOS accuracy is unclear; however, polymer ISB can wear with multiple reuse and sterilization methods. Among patient‐related factors, additional variables should be considered, namely arch (maxillary vs. mandibular arch), implant position in the arch, inter‐implant distance, implant depth, and angulation. Conclusions: Ambient lighting conditions should be established based on the IOS selected to optimize the accuracy of intraoral digital implant scans. The optimal scanning pattern may vary based on the IOS, clinical situation, and the number of implants. The optimal ISB design may vary depending on the IOS used. Metallic implant scan bodies are preferred over polymer ISB designs to minimize wear due to multiple use and sterilization distortion. Among patient‐related factors, additional variables should be considered namely the arch scanned, implant position in the arch, inter‐implant distance, implant depth, and angulation. The impact of these factors may vary depending on the IOS selected. [ABSTRACT FROM AUTHOR]

Objectives: To provide an overview about the current approaches to prevent peri‐implant diseases in edentulous patients with complete‐arch implant‐supported prostheses, and to review the clinical applications of the latest digital technologies for implant prosthodontics. Methods: A review of the guidelines to prevent peri‐implant diseases in patient's receiving complete‐arch implant‐supported prostheses including facially driven treatment planning procedures using either conventional or digital methods, computer‐aided implant planning procedures, and prosthodontic design variables including the optimal number and distribution of dental implants, implant to abutment connection type, implant or abutment level design, screw‐ or cement‐retained alternatives, prostheses contours, and material selection is provided. Furthermore, an outline of the current therapeutic management approaches to address peri‐implant diseases is reviewed. Conclusions: Clinicians should understand and know different planning and design‐related variables that can affect biological and mechanical complication rates of complete‐arch implant‐supported prostheses. Maintenance protocols are fundamental for minimizing biological and mechanical complications. [ABSTRACT FROM AUTHOR]

Objective: This article describes the use of flowable injectable composite resins to facilitate transitional treatment of a complex complete mouth rehabilitation. Clinical Considerations: Some patients require urgent and complex complete mouth rehabilitations that are time and cost intensive. Financial considerations can prevent some patients from pursuing treatment. This can result in the oral conditions worsening over time and compromising the long‐term prognosis of the teeth. Conclusions: Injectable composite resins can be used as a transitional bonding material for complex cases using an injection molding technique utilizing clear indices obtained from a diagnostic waxing. This allows for a full mouth rehabilitation to be performed in a single appointment, producing instant results. Clinical Significance: Transitioning with injectable composite as demonstrated in this case will immediately stabilize an otherwise deteriorating situation in a cost‐effective way and allows patients to address the realities of financial or time constraints when transitioning to more durable porcelain restorations over a period of years. [ABSTRACT FROM AUTHOR]

Objective: This article will explain and demonstrate the application of analog smile design techniques and concepts as a precursor for digital smile design implementation. The application of these techniques will be described with two case presentations that will demonstrate the incorporation of these analog methods into digital smile design programs. Clinical Considerations: Digital smile design workflows can be more efficient and require less chair time but must be based on an understanding and application of basic smile design principles to apply the digital techniques successfully. Conclusions: The application of basic smile design techniques to digital workflows resulted in excellent clinical outcomes for both a localized treatment plan and a full mouth restorative rehabilitation. Clinical Significance: Digital smile design is quickly being adopted into dental practices. However, the digital design must be created by the clinician and be based on a thorough understanding of basic esthetic and restorative principles to achieve predictable successful clinical outcomes. [ABSTRACT FROM AUTHOR]

Objective: To explore a possible morphological relationship between buccal corridor, gingival display, transpalatal molar width, palatal height, and a cephalometric measurement (PV‐A Line) as a risk indicator for sleep‐disordered breathing. Materials and Methods: Thirty subjects were enrolled. Full face maximum smile images and CBCT scans were taken. A Pearson correlation coefficient was used to identify any relationships between the variables. Results: No correlations were identified between any of the variables investigated in this study as they relate to risk factors for sleep‐disordered breathing. Conclusions: The amount of buccal corridor space in relation to a patient's smile and the amount of gingival display does not appear to be a reliable metric in identifying certain morphological risk factors for sleep‐disordered breathing. Clinical Significance: Assessing the amount of buccal corridor space in relation to a smile does not appear to be a reliable predictor of morphological risk for certain risk factors of sleep‐disordered breathing. In addition, utilizing the amount of gingival display in a patient's maximum smile does not appear to relate directly to risks in sleep‐disordered breathing. Other tests and discovery may be necessary to identify these types of patients. [ABSTRACT FROM AUTHOR]

Objective: To describe a technique for fabricating an additively manufactured maxillary occlusal device using a complete digital workflow. Clinical Considerations: The maxillary occlusal device design may include an anterior platform to guide the positioning of the mandible in a reproducible position for facilitating the delivery procedure. Conclusions: The described technique provides a more efficient and less time‐consuming method for designing and manufacturing a printed occlusal device, when compared with conventional fabrication techniques. Clinical Significance: The additively manufactured occlusal device designed with an anterior platform guides the positioning of the mandible in a reproducible position, facilitates the delivery procedures, and produces a more efficient and less time‐consuming method when compared with conventional methods. [ABSTRACT FROM AUTHOR]

Objective: This study was initiated to validate a predictable system for establishing maximum maxillary lip dynamics and highlight the clinical significance of the findings. Materials and Methods: Seventy‐five subjects, ranging in age from 25 to 71 years old were photographed with lips in maximum and minimum reveal. The images were digitally analyzed using set references. The statistical analysis was performed using Meta. Numerics version 4.1.4. A Pearson correlation coefficient (r) was carried out to identify relationships between age and maxillary lip dynamics. A p‐value less than or equal to 0.05 was considered to be significant. Results: A greater percentage of participants have posterior gingival display than anterior gingival display. There is greater movement of the maxillary lip at the cuspid than at the central incisor. Conclusion: There was a tendency for lip dynamics to increase at the right central incisor when there is an increase in lip dynamics at the right cuspid. Lip dynamics does not appear to decrease with age. Clinical Significance: Accurately recording and considering maximum lip dynamics helps avoid asymmetric, excessive or insufficient gingival architecture, insufficient or excessive tooth length and visible restorative margins. [ABSTRACT FROM AUTHOR]

Objectives: Within the development of digital technologies, dental professionals aim to integrate virtual diagnostic articulated casts obtained by using intraoral scanners (IOSs), the mandibular motion of the patient recorded by using an optical jaw tracking system, and the information provided by computerized occlusal analysis systems. This article describes the various digital technologies available for obtaining the digital occlusion of a patient and outlines its challenges and limitations. Overview: The factors that influence the accuracy of the maxillomandibular relationship of diagnostic casts obtained by using IOSs are reviewed, as well as the occurrence of occlusal collisions or mesh interpenetrations. Different jaw tracking systems with varying digital technologies including ultrasonic systems, photometric devices, and artificial intelligence algorithms are reviewed. Computerized occlusal analysis systems for detecting occlusal contacts in a time sequential manner with the pressure distribution on the occlusal surfaces are reviewed. Conclusions: Digital technologies provide powerful diagnostic and design tools for prosthodontic care. However, the accuracy of these digital technologies for acquiring and analyzing the static and dynamic occlusion need to be further analyzed. Clinical Significance: Efficiently implementing digital technologies into dental practice requires an understanding of the limitations and state of current development of the digital acquisition methods for digitizing the static and dynamic occlusion of a patient by using IOSs, digital jaw trackers, and computerized occlusal analysis devices. [ABSTRACT FROM AUTHOR]

Objectives: To measure the influence of arch location and scanning pattern on the accuracy, scanning time, and number of photograms of complete‐arch implant scans acquired using an intraoral scanner (IOS). Materials and Methods: A maxillary (maxillary group) and mandibular (mandibular group) model with 6 implant abutments on each cast was digitized using a desktop scanner (control scans). Six subgroups were created based on the scanning pattern used to acquire the scans using an IOS (Trios 4): occluso‐buccal‐lingual (OBL subgroup), occluso‐linguo‐buccal (OLB subgroup), bucco‐linguo‐occlusal (BLO subgroup), linguo‐buccal‐occlusal (LBO subgroup), zigzag (ZZ subgroup), and circumferential (C subgroup). The control scans were used as a reference to measure the discrepancy with the experimental scans calculating the root mean square error. Two‐way ANOVA and the pairwise comparison Tukey tests were used to analyze the data (α =.05). Results: Significant discrepancies in trueness (p <.001), precision (p <.001), scanning time (p <.001), and number of photograms (p <.001) were found. The maxillary group obtained poorer trueness and precision values, higher scanning times, and a larger number of photograms than the mandibular group. The C subgroup obtained the best trueness and precision values, but was not significantly different from the OLB, BLO, and LBO subgroups. The ZZ subgroup obtained the worst trueness and precision values (p <.05). The C subgroup obtained the lowest scanning time and number of photograms (p <.05). Conclusions: Arch location and scanning pattern influenced scanning accuracy, scanning time, and number of photograms of complete‐arch implant scans. [ABSTRACT FROM AUTHOR]

Purpose: To measure the flexural strength and Weibull characteristics of aged and nonaged printed interim dental material fabricated with different layer thickness. Material and methods: Bars (25×2×2 mm) were additively fabricated by using a polymer printer (Asiga Max) and an interim resin (Nexdent C&B MFH). Specimens were fabricated with the same printing parameters and postprocessing procedures, but with 7 different layer thickness: 50 (control or 50‐G group), 10 (10‐G group), 25 (25‐G group), 75 (75‐G group), 100 (100‐G group), 125 (125‐G group), and 150 μm (150‐G group). Two subgroups were created: nonaged and aged subgroups (n = 10). A universal testing machine was selected to measure flexural strength. Two‐parameter Weibull distribution values were computed. Two‐way ANOVA and Tukey tests were selected for statistical evaluation of the data (α = 0.05). Results: Artificial aging methods (p < 0.001) were a significant predictor of the flexural strength computed. Aged specimens acquired less flexural strength than nonaged specimens. The Weibull distribution obtained the highest shape for nonaged 50‐G and 75‐G group specimens compared with those of other nonaged groups, while the Weibull distribution showed the highest shape for aged 125‐G specimens. Conclusions: The flexural strength of the additively fabricated interim material examined was not influenced by the layer thickness at which the specimens were fabricated; however, artificial aging techniques reduced its flexural strength. Aged specimens presented lower Weibull distribution values compared with nonaged specimens, except for the 125‐G specimens. [ABSTRACT FROM AUTHOR]

Purpose: To assess the influence of the number of teeth (2, 3, or 4) and location (molars, molar and premolar, or premolars and canines) of the bilateral virtual occlusal record on the accuracy of the virtual maxillo‐mandibular relationship acquired by an intraoral scanner (IOS). Material and methods: Diagnostic casts mounted on a semi‐adjustable articulator were obtained. Four markers were adhered on the facial surfaces of the first molars and canines. The mounted casts were digitized using an extraoral scanner. Maxillary and mandibular intraoral digital scans were obtained using an intraoral scanner (TRIOS 4). The maxillary and mandibular digital scans were duplicated 105 times and divided into 7 groups based on the number of teeth (2, 3, or 4) and location (molar, molar and premolar, or premolars and canines) of the bilateral virtual occlusal records (n = 15). The alignment of the scans was automatically performed after the acquisition of the corresponding occlusal records by the IOS program. Eight linear distances between the gauge balls were computed on the reference scan and on the 105 digital scans. The distances obtained on the reference scan were used to calculate the discrepancies with the distances obtained on each experimental scan. The Shapiro‐Wilk test showed that the data was normally distributed. The trueness and precision data were analyzed using 2‐way ANOVA followed by pairwise comparison Tukey tests (α = 0.05). Results: Two‐way ANOVA showed that the number of teeth (p < 0.001) and the position of the virtual occlusal record (p < 0.001) were significant factors on the accuracy of the maxillo‐mandibular relationship. Tukey test showed significant overall mean differences between the different groups tested: the 4‐teeth group obtained the highest trueness, and the 2‐teeth group showed the lowest trueness values (p < 0.001). Tukey test showed significant trueness differences between the virtual occlusal record locations. The 2‐teeth record located more posteriorly obtained the lowest trueness. Significant differences in precision values were found among the subgroups tested (p < 0.001). The 2‐teeth group obtained significantly more precision values than the 3‐ and 4‐teeth groups. Additionally, there was a significant difference in precision values between the subgroup tested in which the first molar and second premolar location had the highest precision, while the first and second premolar's location obtained the lowest precision. Conclusions: The number of teeth and the location of the bilateral virtual occlusal record influenced the accuracy of the virtual maxillo‐mandibular relationship obtained by the intraoral scanner tested. The more teeth included in the bilateral virtual occlusal record, the higher the accuracy of the maxillo‐mandibular relationship. Additionally, the more anteriorly located the virtual bilateral occlusal record involving 2 or 3 teeth was, the higher the accuracy mean value. [ABSTRACT FROM AUTHOR]

Objectives: To describe the factors related to patient intraoral conditions that impact the scanning accuracy of intraoral scanners (IOSs). A new classification for these influencing factors is proposed to facilitate dental professionals' decision‐making and maximize the accuracy and reliability of intraoral digital scans. Overview: Variables related to intraoral conditions of the patient that can influence the scanning accuracy of IOSs include tooth type, presence of interdental spaces, arch width variations, palate characteristics, wetness, existing restorations, characteristics of the surface being digitized, edentulous areas, interimplant distance, position, angulation, and depth of existing implants, and implant scan body selection. Conclusions: The knowledge and understanding of the patient's intraoral conditions that can impact the scanning accuracy of IOSs is a fundamental element for maximizing the accuracy of IOSs. Clinical Significance: The patient's intraoral conditions, or patient factors, can significantly impact intraoral scanning accuracy. Dental professionals must know and understand these influencing patient factors to maximize the accuracy of IOSs. [ABSTRACT FROM AUTHOR]

Objectives: To describe the factors related to the operator skills and decisions that influence the scanning accuracy of intraoral scanners (IOSs). A new classification for these factors is proposed to facilitate dental professionals' decision making when using IOSs and maximize the accuracy and reliability of intraoral digital scans. Overview: Each IOS system is limited by the hardware and software characteristics of the selected device. The operator decisions that can influence the accuracy of IOSs include the scanning technology and system selection, scanning head size, calibration, scanning distance, exposure of the IOS to ambient temperature changes, ambient humidity, ambient lighting conditions, operator experience, scanning pattern, extension of the scan, cutting off, rescanning, and overlapping procedures. Conclusions: The knowledge and understanding of the operator factors that impact scanning accuracy of IOSs is a fundamental element for maximizing the accuracy of IOSs and for successfully integrating IOSs in daily practices. Clinical Significance: Operator skills and clinical decisions significantly impact intraoral scanning accuracy. Dental professionals must know and understand these influencing operator factors for maximizing the accuracy of IOSs. [ABSTRACT FROM AUTHOR]

A step‐by‐step technique is described for tracking and recording, in real time, the lip dynamics of a patient and integrating them into a 3D virtual patient representation using facial trackers and motion engine software programs. The main advantage of this technique is that it enables capturing of the lip movements of the patient in real time; therefore, the lip movements are not simulated from a previously recorded video of the patient using animation software programs. [ABSTRACT FROM AUTHOR]

A review of the main additive manufacturing technologies including vat‐polymerization, material extrusion, material jetting, binder jetting, powder‐based fusion, sheet lamination, and direct energy deposition is provided. Additionally, the dental applications of polymer, metal, and ceramic printing technologies are discussed. [ABSTRACT FROM AUTHOR]

Although the evolution of digital technology continues to improve patient data acquisition, the ability to both standardize the recording of the maxillary occlusal plane and capture the necessary dynamic data for dento‐facial analysis remains elusive. This article describes step‐by‐step techniques to position the maxilla on an articulator using the natural head position and a facial reference system (Kois Facial Reference Glasses) for both analog and digital workflows. A photographic technique will be presented that captures the natural head position and allows the clinician to align a 2D reference photograph with the maxillary intraoral digital scan and the virtual articulator. Using this reference photograph, the clinician can record and communicate to the technician the maxillary arch position in relationship with the facial references, as well as transfer the additively manufactured casts in the same facial orientation for mounting and analysis either virtually or on an analog articulator. [ABSTRACT FROM AUTHOR]

ABSTRACT Clinical Considerations Objective Conclusions Conventional facebow records are used to transfer the maxillary cast into the analog articulator. Different reference planes have been described, including the true horizontal or gravity reference plane. A conventional facebow (Kois Dentofacial Analyzer; Panadent) allows the recording of the gravity plane for transferring the maxillary cast into the analog semi‐adjustable articulator. Clinical procedures should also allow the maxillary scan transfer into the virtual articulator by using the true horizontal reference plane.The present manuscript describes the step‐by‐step protocol to record the gravity plane and to transfer the maxillary scan into the virtual articulator by using an extraoral scan body system.The extroral scan body device enables the substitution of the conventional facebow procedure. Additionally, this extraoral scan body is fabricated by using additive manufacturing technologies and eases the complete digital workflow for transferring the maxillary scan into the virtual articulator. [ABSTRACT FROM AUTHOR]

Problem Although there is a high prevalence of noncarious cervical lesions ( NCCLs), the etiology of these lesions remains contentious. Purpose To evaluate the combined effects of cyclic fatigue stress and biocorrosion activity on NCCLs. Materials and Methods Extracted premolar teeth were allocated into four groups ( N = 10). Two groups were cyclically fatigue loaded (100 N; 72 cycles per minute; 9,200 cycles) and placed in either hydrochloric acid gel ( pH = 0.1) or orange juice ( pH = 4). The other two groups were stored in identical chemical solutions without fatigue load. The buccal-lingual width of each tooth was measured before and after testing. The depth of biocorrosion, normalized by the percentage change in buccolingual width, normalized by time (hour) was calculated. The data were analyzed using a two-way analysis of variance and Tukey's HSD multiple comparison test (α = 0.05). Results Mean ( SD) of the depth of biocorrosion values were as follows: teeth receiving fatigue loading with hydrochloric acid gel exposure (1.003%/hour [0.063]) revealed a significantly higher depth of biocorrosion than the fatigue-loaded group with orange juice exposure (0.511%/hour [0.281]) ( p < 0.01). For the groups without fatigue loading, those with hydrochloric acid gel (0.022%/hour [0.006]) had a significantly higher depth of biocorrosion than the group with orange juice (0.009%/hour [0.004]) ( p < 0.01). The cyclically fatigue-loaded teeth with hydrochloric acid gel had a significantly greater depth of biocorrosion than either group without fatigue loading ( p < 0.001). Conclusions Cyclic fatigue stress-acidic biocorrosion had a significant effect on the depth of the NCCLs. Clinical Significance In order to manage the destructive NCCLs lesions properly, it is essential to understand the etiology of these lesions. The present study indicated that the combined mechanisms of cyclic fatigue stress and biocorrosion could contribute to the formation of NCCLs. [ABSTRACT FROM AUTHOR]

Statement of Problem Interest in posterior partial coverage restorations has increased because these restorations provide a more conservative treatment option than traditional cohesively based restorations; however, material selection has been a controversial topic in the current literature. Purpose To evaluate the fracture resistance of posterior partial coverage restorations restored with different materials, examine their stress distribution, and calculate failure risks using three-dimensional (3 D) finite element analysis. Methods Sixty extracted third molar teeth received 2-mm occlusal reduction maintaining cusp steepness of 45 degrees relative to occlusal surface. Teeth were allocated into four groups ( N = 15) and restored with different materials: feldspathic ceramic, leucite-reinforced ceramic, lithium disilicate-reinforced ceramic ( EMX), or indirect resin-based composite ( COM). Restorations were luted with resin cement and submitted to compressive loads ( Instron Corp, Norwood, MA, USA). The data were analyzed with one-way analysis of variance, followed by Tukey's HSD tests. A 3 D finite element model of posterior partial coverage restorations was developed and validated. The model was used to approximate the maximum principal stress in each of the materials under a 100- N static vertical compression at the occlusal surface of the tooth. The risk of restoration failure was quantified and compared among the four different materials. Results Group EMX had fracture resistance significantly higher than other testing groups. Group COM presented the most extensive fractures involving tooth and root structures. When compared with the other materials, group EMX exhibited higher stress concentration; however, the failure risk of the restoration was lower. Conclusions Fracture resistance and failure risks of posterior partial coverage restorations are significantly influenced by material selection. Clinical Significance Many restorative materials have been advocated for partial coverage restorations. It is essential to ensure that restorative materials have sufficient strength to support occlusal forces and, in case of fracture, the remaining tooth structure is not compromised or placed at risk. This study revealed that all-ceramic materials had high incidences of fractures involving the materials themselves, whereas the predominant failure of resin-based composite involved the tooth structure in a catastrophic manner. [ABSTRACT FROM AUTHOR]

Background: Attempts have teen made to evaluate the biologic dimension of osseointegrated implants; however, most are histologic studies in animals, and the effect of soft tissue support from adjacent teeth on the interproximal dimension of the peri-implant mucosa for anterior single implants has not been addressed. This study clinically evaluated the dimensions of the peri-implant mucosa around 2-stage maxillary anterior single implants in humans after 1 year of function. The influence of the peri-implant biotype was also examined. Methods: Forty-five patients (20 males and 25 females) with a mean age of 47.3 years were included in this study. A total of 45 maxillary anterior single implant crowns with a mean functional time of 32.5 months (range, 12 to 78) were evaluated. The dimensions of peri-implant mucosa were measured by bone sounding using a periodontal probe at the mesial (MI), mid-facial (F), and distal (DI) aspects of the implant restoration and the proximal aspects (MT, DT) of adjacent natural teeth. In addition, the peri-implant biotype was evaluated and categorized as thick or thin. Statistical analysis was performed using an independent t test (P <0.05). Results: The means and standard deviations of the dimensions of peri-implant mucosa at MT, MI, F, DI, and DT were 4.20 ± 0.77 mm. 6.17 ± 1.27 mm, 3.63 ± 0.91 mm, 5.93 ± 1.21 mm, and 4.20 ± 0.64 mm, respectively. The dimensions of peri-implant mucosa in the thick, biotype were significantly greater than the thin biotype at MT, MI, and DT (P <0.05). Conclusions: The mean facial dimension of peri-implant mucosa of 2-stage implants is slightly greater than the average dimension of the dentogingival complex. The level of the interproximal papilla of the implant is independent of the proximal bone level next to the implant, but is related lo the interproximal bone level next to the adjacent teeth. Greater peri-implant mucosal dimensions were noted in the presence of a thick peri-implant biotype as compared to a thin biotype. [ABSTRACT FROM AUTHOR]

Achieving periodontal harmony commensurate with the requirements of restorative dentistry and esthetics at times seems diametrically opposed. Blending in the gingival esthetic components of symmetrical levels, form/a degree of scallop, and the amount of gingival display (see Part 11) with the restorative mechanical prerequisites of incisaVocclusa1 reduction, preparation length, and adequate sound tooth structure (see Part 111) provides key guidelines for therapy. However, in order to provide predictable esthetic results, two essential biologic issues must be fully understood. [ABSTRACT FROM AUTHOR]

ABSTRACT Objectives Overview Conclusions Clinical Significance To classify the complete‐arch implant scanning techniques recorded by using intraoral scanners (IOSs).Different implant scanning techniques have been described for recording complete‐arch implant scans by using IOSs. However, dental literature lacks on a classification of these implant scanning techniques. Implant scanning techniques aim is to record the 3‐dimensional position of the implants being scanned, while implant scanning workflows require additional scans to record all the information needed for designing an implant prosthesis. This additional information includes soft tissue information, tooth position, antagonist arch, and maxillomandibular relationship.There are five complete‐arch implant scanning techniques captured by using IOSs: non‐splinting, non‐calibrated splinting, calibrated implant scan bodies, calibrated frameworks, and reverse impression methods. The digital workflow varies depending on the implant scanning technique selected.The understanding of the varying implant scanning techniques and the main differences among them may ease the decision criteria for recording digital implant scans by using intraoral scanners. [ABSTRACT FROM AUTHOR]

The article presents the authors views on a study on the emergence angles of the cementoenamel junction in natural anterior teeth. The author states that the study created an innovative protocol for studying the emergence angles of natural teeth. According to the author, the clinical importance of the study may provide the technician with data when fabricating contour parameters.

Objectives: The different scanning errors that can be caused by the operator handling an intraoral scanner (IOS) or the intraoral conditions of the patient being scanned have not been described. The purpose of this review was to describe and classify the scanning errors that can be identified in digital scans recorded by using IOSs., Overview: The identification of scanning errors in an intraoral scan and understanding the cause of these scanning errors are fundamental procedures for successfully handling an IOS and integrating these digital data acquisition technologies in dental practices. There are two main types of scanning errors: the ones created by the operator and the ones caused by the intraoral conditions of the patient. There are seven operator-related scanning errors: mesh hole, stitching, tissue, reliability, umbrella, implant scan body geometry, and scanning noise errors. Additionally, there are four patient-related scanning errors: humidity, bridge, fuzzy finish line, and scanability noise errors., Conclusions: The identification of scanning errors is fundamental for assessing the quality of an intraoral digital scan. The comprehensive reading of these scanning errors allows the dental professional to understand if the scanning error can be corrected or if it is related to hardware/software limitations of IOSs., (© 2025 Wiley Periodicals LLC.)