The learning curve of a dynamic navigation system used in endodontic apical surgery.

Background/purpose: Quantitative research was conducted on the learning process of a dynamic navigation system. This study provides guidance for the promotion and application of dynamic navigation technology in the endodontic apical surgery field.

Materials And Methods: Standardized models were designed and 3D printed to form the approach operation of endodontic apical surgery.

Risk factors for gingival invagination: A retrospective study.

Aim: This study aimed to identify the risk factors for gingival invagination during orthodontic treatment after premolar extraction.

Materials And Methods: The medical records of 135 patients who had undergone interdental space closure after premolar extraction were collected, and cone beam computed tomography was performed to determine the presence of gingival invagination. The risk factors were examined using mixed-effects models and generalized propensity score weighting (GPSW) to develop a predictive model.

Accuracy and efficiency of dynamic navigated root-end resection in endodontic surgery: a pilot in vitro study.

Background: The operation accuracy and efficiency of dynamic navigated endodontic surgery were evaluated through in vitro experiments. This study provides a reference for future clinical application of dynamic navigation systems in endodontic surgery.

Materials And Methods: 3D-printed maxillary anterior teeth were used in the preparation of models for endodontic surgery.

Automatic extraction of facial median sagittal plane for patients with asymmetry based on the EDMA alignment algorithm.

Background: We aimed to establish a novel method for automatically constructing three-dimensional (3D) median sagittal plane (MSP) for mandibular deviation patients, which can increase the efficiency of aesthetic evaluating treatment progress. We developed a Euclidean weighted Procrustes analysis (EWPA) algorithm for extracting 3D facial MSP based on the Euclidean distance matrix analysis, automatically assigning weight to facial anatomical landmarks.

Methods: Forty patients with mandibular deviation were recruited, and the Procrustes analysis (PA) algorithm based on the original mirror alignment and EWPA algorithm developed in this study were used to construct the MSP of each facial model of the patient as experimental groups 1 and 2, respectively.

Automatic three-dimensional facial symmetry reference plane construction based on facial planar reflective symmetry net.

Objectives: Three-dimensional (3D) facial symmetry analysis is based on the 3D symmetry reference plane (SRP). Artificial intelligence (AI) is widely used in the dental and oral sciences. This study developed a novel deep learning model called the facial planar reflective symmetry net (FPRS-Net) to automatically construct an SRP and established a method for defining a 3D point-cloud region of interest (ROI) and high-dimensional feature computations suitable for this network model.

Chairside digital design and manufacturing method for children's band and loop space maintainers.

Objectives: This study proposes a chairside digital design and manufacturing method for band and loop space maintainers and preliminarily validates its clinical feasibility.

Methods: Clinical cases of 10 children requiring space maintenance caused by premature loss of primary teeth were collected. Intraoral scan data of the affected children were also collected to establish digital models of the missing teeth.

Three-Dimensional Virtual Reconstruction of External Nasal Defects Based on Facial Mesh Generation Network.

(1) Background: In digital-technology-assisted nasal defect reconstruction methods, a crucial step involves utilizing computer-aided design to virtually reconstruct the nasal defect's complete morphology. However, current digital methods for virtual nasal defect reconstruction have yet to achieve efficient, precise, and personalized outcomes. In this research paper, we propose a novel approach for reconstructing external nasal defects based on the Facial Mesh Generation Network (FMGen-Net), aiming to enhance the levels of automation and personalization in virtual reconstruction.

[Current Status and Analysis of the Clinical Application of Digital Technology in Oral Medicine].

With the increasing maturity and popularization of digital technology in oral medicine, its application has now expanded to various clinical subspecialties of oral medicine. Digitalization has become one of the important development directions of oral medicine. What is the current development status of digital technology in oral medicine? In what ways is digital technology applied across various clinical specialties of oral medicine? Dentists are particularly concerned about these issues in their clinical work and research.

[Preliminary evaluation of chin symmetry with three dimentional soft tissue spatial angle wireframe template].

Objective: To develop an efficient and robust method based on three dimensional facial landmarks for evaluating chin region asymmetry at the soft tissue level and to compare it with the traditional mirror-overlap analysis method in order to test its availability.

Methods: Standard symmetrical face was used for mental tubercle coordinate transformation so as to filter soft tissue three dimensional spatial angle and construct corresponding three dimensional spatial angle wireframe template. Ten patients aged 12-32 years with clinical chin region asymmetry diagnosis at the Department of Orthodontics of Peking University Hospital of Stomatology from November 2020 to November 2021 were randomly selected.

Evaluation of three-dimensional reconstructed palatal morphology in skeletal class III subjects with different vertical patterns using cone beam computed tomography.

Background: This study aims to evaluate the difference of three-dimensional (3D) reconstructed palatal morphology between subjects with skeletal Class III and skeletal Class I in different vertical patterns using cone beam computed tomography (CBCT).

Methods: In this study, 89 subjects with skeletal Class III (49 females, 40 males; 25.45 ± 3.

Three-dimensional assessment of periodontal support of lower incisors for skeletal Class II malocclusion undergoing presurgical orthodontic treatment with different vertical skeletal patterns.

Background: The aim of the present study was to compare periodontal support changes during retraction of mandibular anterior teeth for skeletal Class II malocclusion with different facial divergence and to analyze relevant factors influencing bone remodeling by applying three-dimensional (3D) cone-beam computed tomography (CBCT) reconstruction technology.

Methods: Forty-eight patients with Class II malocclusion requiring surgical orthodontic treatment enrolled in the study were divided into the hyperdivergent group (n = 16), normodivergent group (n = 16) and hypodivergent group (n = 16) according to their vertical skeletal patterns. Cone-beam computed tomography (CBCT) scans were obtained before treatment (T1) and after presurgical orthodontic treatment (T2).

Effect of storage temperature on the dimensional stability of DLP printed casts.

Statement Of Problem: Despite studies focusing on the accuracy and dimensional stability of additive manufacturing, research on the impact of storage conditions on these properties of 3-dimensional (3D) printed objects is lacking.

Purpose: The purpose of this in vitro study was to investigate the influence of storage temperature on the dimensional stability of digital light processing (DLP) printed casts and to determine how different locations in printed casts react differently.

Material And Methods: A completely dentate maxillary typodont model was digitized with a desktop laser scanner.

Clinical evaluation and quantitative occlusal change analysis of posterior implant-supported all-ceramic crowns: A 3-year randomized controlled clinical trial.

Objectives: To compare the survival and complication rates of posterior screw-retained monolithic lithium disilicate (LS )/veneered zirconia (ZrO ) single implant crowns (SICs), as well as analyze the occlusal changes observed during a 3-year follow-up period.

Materials And Methods: Thirty-three patients were included and randomly divided into two groups. The test group consisted of 17 patients who received monolithic-LS -SIC, while the control group consisted of 16 patients who received veneered-ZrO -SIC.

Slim the face or not: 3D change of facial soft and hard tissues after third molars extraction: a pilot study.

Background: Whether slim the face or not after removed third molars is the concern of some orthodontic treatment candidates. The aim of this article is to explore the volume changes of facial soft and hard tissues after third molars extraction, as well as develop a reproducible clinical protocol to precisely assess facial soft tissue volume change.

Methods: A non-randomized, non-blind, self-controlled pilot study was conducted.

Subjective evaluation of facial asymmetry with three-dimensional simulated images among the orthodontists and laypersons: a cross-sectional study.

Objectives: We used three-dimensional (3D) virtual images to undertake a subjective evaluation of how different factors affect the perception of facial asymmetry among orthodontists and laypersons with the aim of providing a quantitative reference for clinics.

Materials And Methods: A 3D virtual symmetrical facial image was acquired using FaceGen Modeller software. The left chin, mandible, lip and cheek of the virtual face were simulated in the horizontal (interior/exterior), vertical (up/down), or sagittal (forward or backward) direction in 3, 5, and 7 mm respectively with Maya software to increase asymmetry for the further subjective evaluation.

Accuracy of three-dimensional periodontal ligament models generated using cone-beam computed tomography at different resolutions for the assessment of periodontal bone loss.

Objective: To develop a method for generating three-dimensional (3D) digital models of the periodontal ligament (PDL) using 3D cone-beam computed tomography (CBCT) reconstruction and to evaluate the accuracy and agreement of the 3D PDL models in the measurement of periodontal bone loss.

Methods: CBCT data collected from four patients with skeletal Class III malocclusion prior to periodontal surgery were reconstructed at three voxel sizes (0.2 mm, 0.

Enhanced Lip-Contour During Facial Scan for 3D DSD and Implant Planning: A Blue Screen Approach.

When obtaining 3-dimensional (3D) facial images for digital smile design (DSD) and dental implant planning, inaccuracies may frequently be introduced by distortion in the region between the lips' vermilion border and the teeth. The present clinical technique aimed to reduce such deformation during face scanning, thereby facilitating 3D DSD. This is also essential to plan bone reduction with precision for implant reconstructions.

Perceptual difference of smile aesthetics between 2-dimensional photographs and 3-dimensional dentofacial images: a cross-sectional study.

Background: The aim of this study was to compare the perceptual difference of smile aesthetics between 2D photographs and 3D dentofacial images as perceived by orthodontists and graduate students.

Methods: Forty-eight subjects finished orthodontic treatment were recruited with 2D photographs of frontal, oblique and lateral views as well as 3D dentofacial images. Twelve senior orthodontists and 13 postgraduate students were asked to rate the 2D and 3D smile simulations based on visual analog scale (VAS) and to vote for smile features that affect the attractiveness of smile.

Digital versus radiographic accuracy evaluation of guided implant surgery: an in vitro study.

Background: Cone-beam computed tomography (CBCT) is the most widely used method for postsurgical evaluation of the accuracy of guided implant surgery. However, the disadvantages of CBCT include radiation exposure, artifacts caused by metal implants, and high cost. Few studies have introduced a digital registration method to replace CBCT for evaluating the accuracy of guided surgery.

3D-printed titanium surgical guides for extraction of horizontally impacted lower third molars.

Objectives: This prospective study introduced a digitally designed sectioning guide and evaluated its feasibility for the extraction of horizontally impacted lower third molars.

Materials And Methods: This study included 38 horizontally impacted lower third molars, randomly divided into experimental and control groups. The teeth were extracted using a 3D-printed titanium surgical guide in the experimental group; free-hand extractions were performed in the control group.

Three-dimensional measurement of periodontal support during surgical orthodontic treatment of high-angle skeletal Class III malocclusion: A retrospective study.

Introduction: This study aimed to quantify the periodontal health of incisors during surgical orthodontic treatment in patients with high-angle Class III malocclusion using a cone-beam computed tomography (CBCT) 3-dimensional (3D) reconstruction technique.

Methods: The sample consisted of 30 patients with high-angle Class III malocclusion (mean age, 20.53 ± 2.

[Preliminary study on the method of automatically determining facial landmarks based on three-dimensional face template].

To explore the establishment of an efficient and automatic method to determine anatomical landmarks in three-dimensional (3D) facial data, and to evaluate the effectiveness of this method in determining landmarks. A total of 30 male patients with tooth defect or dentition defect (with good facial symmetry) who visited the Department of Prosthodontics, Peking University School and Hospital of Stomatology from June to August 2021 were selected, and these participants' age was between 18-45 years. 3D facial data of patients was collected and the size normalization and overlap alignment were performed based on the Procrustes analysis algorithm.