External Validation of the Effect of the Combined Use of Object Detection for the Classification of the C-Shaped Canal Configuration of the Mandibular Second Molar in Panoramic Radiographs: A Multicenter Study.

INTRODUCTION: The purposes of this study were to evaluate the effect of the combined use of object detection for the classification of the C-shaped canal anatomy of the mandibular second molar in panoramic radiographs and to perform an external validation on a multicenter dataset. METHODS: The panoramic radiographs of 805 patients were collected from 4 institutes across two countries. The CBCT data of the same patients were used as "Ground-truth". Five datasets were generated: one for training and validation, and 4 as external validation datasets. Workflow 1 used manual cropping to prepare the image patches of mandibular second molars, and then classification was performed using EfficientNet. Workflow 2 used two combined methods with a preceding object detection (YOLOv7) performed for automated image patch formation, followed by classification using EfficientNet. Workflow 3 directly classified the root canal anatomy from the panoramic radiographs using the YOLOv7 prediction outcomes. The classification performance of the 3 workflows was evaluated and compared across 4 external validation datasets. RESULTS: For Workflows 1, 2, and 3, the area under the receiver operating characteristic curve (AUC) values were 0.863, 0.861, and 0.876, respectively, for the AGU dataset; 0.935, 0.945, and 0.863, respectively, for the ASU dataset; 0.854, 0.857, and 0.849, respectively, for the ODU dataset; and 0.821, 0.797, and 0.831, respectively, for the ODU low-resolution dataset. No significant differences existed between the AUC values of Workflows 1, 2, and 3 across the 4 datasets. CONCLUSIONS: The deep learning systems of the 3 workflows achieved significant accuracy in predicting the C-shaped canal in mandibular second molars across all test datasets.

Generative adversarial networks in dental imaging: a systematic review.

OBJECTIVES: This systematic review on generative adversarial network (GAN) architectures for dental image analysis provides a comprehensive overview to readers regarding current GAN trends in dental imagery and potential future applications. METHODS: Electronic databases (PubMed/MEDLINE, Scopus, Embase, and Cochrane Library) were searched to identify studies involving GANs for dental image analysis. Eighteen full-text articles describing the applications of GANs in dental imagery were reviewed. Risk of bias and applicability concerns were assessed using the QUADAS-2 tool. RESULTS: GANs were used for various imaging modalities, including two-dimensional and three-dimensional images. In dental imaging, GANs were utilized for tasks such as artifact reduction, denoising, and super-resolution, domain transfer, image generation for augmentation, outcome prediction, and identification. The generated images were incorporated into tasks such as landmark detection, object detection and classification. Because of heterogeneity among the studies, a meta-analysis could not be conducted. Most studies (72%) had a low risk of bias in all four domains. However, only three (17%) studies had a low risk of applicability concerns. CONCLUSIONS: This extensive analysis of GANs in dental imaging highlighted their broad application potential within the dental field. Future studies should address limitations related to the stability, repeatability, and overall interpretability of GAN architectures. By overcoming these challenges, the applicability of GANs in dentistry can be enhanced, ultimately benefiting the dental field in its use of GANs and artificial intelligence.

Evaluating the performance of generative adversarial network-synthesized periapical images in classifying C-shaped root canals.

This study evaluated the performance of generative adversarial network (GAN)-synthesized periapical images for classifying C-shaped root canals, which are challenging to diagnose because of their complex morphology. GANs have emerged as a promising technique for generating realistic images, offering a potential solution for data augmentation in scenarios with limited training datasets. Periapical images were synthesized using the StyleGAN2-ADA framework, and their quality was evaluated based on the average Frechet inception distance (FID) and the visual Turing test. The average FID was found to be 35.353 (± 4.386) for synthesized C-shaped canal images and 25.471 (± 2.779) for non C-shaped canal images. The visual Turing test conducted by two radiologists on 100 randomly selected images revealed that distinguishing between real and synthetic images was difficult. These results indicate that GAN-synthesized images exhibit satisfactory visual quality. The classification performance of the neural network, when augmented with GAN data, showed improvements compared with using real data alone, and could be advantageous in addressing data conditions with class imbalance. GAN-generated images have proven to be an effective data augmentation method, addressing the limitations of limited training data and computational resources in diagnosing dental anomalies.

Medication-related osteonecrosis of the jaw using periodontitis-induced rat before tooth extraction.

OBJECTIVE: This study aimed to investigate the occurrence of medication-related osteonecrosis of the jaw (MRONJ) after tooth extraction due to periodontitis in ovariectomized rats. METHODS: Twenty-four osteoporosis-induced rats were administered with zoledronic acid (ZA; ZA group) or saline (CONT group). In both groups, tooth extraction was performed after inducing periodontitis, and all animals were sacrificed 8-week after tooth extraction. RESULTS: Micro-CT of the tibia showed that the bone volume fraction, bone surface density, trabecular number, and bone mineral density were significantly higher in the ZA group than in the CONT group. Histologically, the proliferative zone on the growth plate was thicker in the ZA group than in the CONT group. Micro-CT of the extraction sites revealed that the bone volume fraction was significantly higher in the ZA group than in the CONT group. Radiologically, the ZA group showed partial healing and delayed healing. Histological analysis revealed normal bone healing status with completely healed epithelium in the extraction sites of the CONT group, whereas abnormal empty osteocytes in the necrotic bone and inflammatory infiltration were observed in the ZA group. CONCLUSION: The incidence of MRONJ increased in the rats administered with ZA.

Allergic reactions to local anesthetic mepivacaine in dental procedures: a case report.

Local anesthetics are an essential part of pain control during dental treatment. Despite its effectiveness and safety, patients should constantly be aware of potential adverse effects, including allergic reactions. Allergic reactions to amide-type local anesthetics (LAs), such as lidocaine and mepivacaine, are rare compared to those to ester-type LAs. Herein, we report the case of a patient with a history of allergy to lidocaine and mepivacaine, with symptoms of itching, diffuse erythema of the wrists and hands, dizziness, and pectoralgia. This case report emphasizes the importance of collecting medical and dental histories of patients is necessary, and how an allergy test in the allergy and clinical immunology department helps select safe LAs for patients.

Evaluation of dental status using a questionnaire before administration of general anesthesia for the prevention of dental injuries.

Background: Dental evaluation and protection are important for preventing traumatic dental injuries when patients are under general anesthesia. The objective of the present study was to develop a questionnaire based on dentition-related risk factors that could serve as a valuable tool for dental evaluation and documentation. Methods: We developed a questionnaire for dental evaluation before administration of general anesthesia, investigated the association between patient-and-dentist responses and mouthguard fabrication, and assessed response agreement between 100 patients. Results: Protective mouthguards were fabricated for 27 patients who were identified as having a high risk of dental injury. There was a strong association between dentists' responses and mouthguard fabrication, depending on the general oral health status, use of ceramic prosthesis, presence of masticatory pain related to periodontal diseases, gingival edema, and implants (P < 0.05). Response agreement between patients and dentists for items related to dental pain, loss of dental pulp vitality, root canal therapy, dental trauma, aesthetic prosthesis, tooth mobility, and implant prosthesis was high (Cohen's kappa coefficient κ ≥ 0.6). Conclusions: A high agreement was observed between patient-dentist responses and a strong association with mouthguard fabrication for items pertaining to ceramic prosthesis, masticatory pain, and dental implants. Patients with a "yes" response to these items are recommended to undergo a dental evaluation and use a dental protective device while under general anesthesia.

Efficacy of tooth brushing via a three-dimensional motion tracking system for dental plaque control in school children: a randomized controlled clinical trial.

BACKGROUND: School children are in a developmental period in which permanent teeth replace primary dentition. It is also a period with a high incidence of gingivitis and caries, which can be improved with adequate tooth brushing. Advances in information technology have led to the development of smart health devices that assist in tooth brushing. We compared the effectiveness of computer-assisted toothbrushing using a toothbrushing instruction (TBI) method called the smart toothbrush and smart mirror (STM) system with that of conventional TBI (verbal instructions) for plaque control in school children. METHODS: This randomized controlled clinical trial analyzed and compared the reduction of the modified Quigley-Hein plaque index between the two methods in 42 school children. The participants were randomly assigned to the STM system group (n = 21) or conventional-TBI group (n = 21). The plaque indices were evaluated at baseline, immediately after TBI (day 0), and 1 week and 1 month after TBI. RESULTS: The STM system and conventional TBI led to an average reduction of 40.50% and 40.57%, respectively, in whole mouth plaque. Reductions in the plaque indices within each tested time period were observed in both groups (P < 0.001), and the mean plaque reduction did not differ between the two groups (P = 0.44). CONCLUSIONS: The present study tested a computer assisted system for TBI, more studies are needed to confirm its usefulness in different objectives. Clinical relevance The computer-assisted STM system may be an alternative of TBI for children. Trial registration ClinicalTrials.gov (NCT04627324) Registered 13/11/2020-Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04627324 .

Identifying the course of the greater palatine artery using intraoral ultrasonography: cohort study.

AIMS: The greater palatine artery (GPA) is one of the most important anatomical structure for free gingival grafts or connective-tissue grafts during soft tissue surgery for dental implants. Several studies have identified the approximate location of the GPA, but it is impossible to detect its exact location during surgery due to large variability between individuals. The authors, therefore, investigated the course of the GPA using intraoral ultrasonography to determine the feasibility of using real-time nonionizing ultrasonography for implant surgery. MATERIALS AND METHODS: This study included 40 healthy young participants. The courses of the GPA were identified using intraoral ultrasound probes from the first premolar to the second molar. The distance from the gingival margin to the GPA (GM-GPA) and the depth of the palatal gingiva from the GPA (PG-GPA) were measured by two independent examiners. Measurements were analyzed statistically, and interexaminer reliability was determined. RESULTS: The distance of the GM-GPA and the mean depth of the PG-GPA were 14.8 ± 1.6 mm and 4.10 ± 0.51 mm (mean ± SD), respectively. GM-GPA decreased when the GPA ran from the second molar to the first molar, and GM-GPA was significantly shorter in females (P < 0.05). PG-GPA increased when the GPA ran to the posterior teeth. Interexaminer measurement agreements were excellent, with intraclass correlation coefficient values of 0.983 and 0.918 for GM-GPA and PG-GPA, respectively. CONCLUSIONS: Using an intraoral ultrasound probe, real-time GPA tracking is possible, which is expected to help reduce the possibility of bleeding during surgery.

Foreign body aspiration and ingestion in dental clinic: a seven-year retrospective study.

Background: This retrospective study investigated the incidence rate of accidental foreign body aspiration and ingestion according to patient sex, age, and dental department. This study aimed to verify whether the incidence rate is higher in geriatric than in younger patients and whether it is different among dental departments. Methods: Accidental foreign body aspiration and ingestion cases were collected from electronic health records and the safety report system of Yonsei University Dental Hospital from January 2011 to December 2017. The collected data included patients' age, sex, medical conditions, treatment procedures, and foreign objects that were accidentally aspirated or ingested. The incidence rate was calculated as the number of accidental foreign body aspirations and ingestions relative to the total number of patient visits. Differences depending on the patients' sex, age, and dental department were statistically identified. Results: There were 2 aspiration and 37 ingestion cases during the 7-year analysis period. The male to female incidence ratio was 2.8:1. The incidence rate increased with age and increased rapidly among those aged 80 years or older. Seven of the 37 patients with accidental foreign body ingestion had intellectual disability, Lou Gehrig's disease, dystonia, or oral and maxillofacial cancer. The incidence rate was highest in the Predoctoral Student Clinic and the Department of Prosthodontics. The most frequently swallowed objects were fixed dental prostheses and dental implant components. Conclusion: The incidence rate of accidental foreign body aspiration and ingestion differed according to patient sex, age, and dental department. Dental practitioners must identify high-risk patients and apply various methods to prevent accidental foreign body aspiration and ingestion in dental clinics. Inexperienced practitioners should be particularly careful.

Conservative orthodontic treatment for severe pathologic migration following total glossectomy: A case report.

Glossectomy combined with radiotherapy causes different levels of tongue function disorders and leads to severe malocclusion, with poor periodontal status in cancer survivors. Although affected patients require regular access to orthodontic care, special considerations are crucial for treatment planning. This case report describes the satisfactory orthodontic management for the correction of severe dental crowding in a 43-year-old female 6 years after treatment for tongue cancer with total glossectomy combined with radiotherapy, to envision the possibility of orthodontic care for oral cancer survivors. Extraction was performed to correct dental crowding and establish proper occlusion following alignment, after considering the possibility of osteoradionecrosis. Orthodontic mini-implants were used to provide skeletal anchorage required for closure of the extraction space and intrusion of the anterior teeth. The dental crowding was corrected, and Class I occlusal relationship was established after 36 months of treatment. The treatment outcome was sustained after 15 months of retention, and long-term follow-up was recommended.

Development and Validation of a Visually Explainable Deep Learning Model for Classification of C-shaped Canals of the Mandibular Second Molars in Periapical and Panoramic Dental Radiographs.

INTRODUCTION: The purpose of this study was to develop and validate a visually explainable deep learning model for the classification of C-shaped canals of the mandibular second molars in dental radiographs. METHODS: The periapical and panoramic images of 1000 mandibular second molars were collected from 372 patients. The diagnostic performance of the deep learning system using periapical and panoramic radiographs was investigated in respect to its ability to determine whether the second mandibular molar showed a C-shaped canal configuration. The assessment of the canal configuration of cone-beam computed tomographic volumes from 372 patients (740 mandibular second molars) was used as a gold standard. RESULTS: The deep convolutional neural network algorithm model showed high accuracy in predicting the C-shaped canal variation among mandibular second molars in both periapical and panoramic images. The model demonstrated best results when using image patches including only the root portion of the tooth and when using both periapical and panoramic images for training (area under the curve [AUC] = 0.99). The model's diagnostic performance using only the root portion of the tooth (AUC: periapical = 0.98 and panoramic = 0.95) was similar to a specialist (AUC: periapical = 0.95 and panoramic = 0.96) and better than a novice general clinician (AUC: periapical = 0.89 and panoramic = 0.91). Both the specialist and general clinician showed better diagnostic performance when reading panoramic radiographs compared with periapical images. CONCLUSIONS: With further optimization of the test data using a larger data set and improvements made in the model, a deep learning system may be expected to effectively diagnose C-shaped canals and aid clinicians in practice and education.

Location of the Mandibular Incisive Canal Related to the Placement of Dental Implants: A Case Report.

Cone-beam computerized tomography (CBCT) can show an uncommon mandibular incisive canal that cannot be detected by panoramic radiography, which is used preoperatively to form the initial plan of the size and length of an implant fixture for surgical placement in the mandibular interforaminal area. Determination of the position and anatomical configuration of the mandibular incisive canal is challenging. The purpose of this case report is to discuss anatomical variations in the mandibular incisive canal and the mental canal by reviewing previous studies. Furthermore, we propose that the anterior loop length of the mental canal near the mental foramen, as well as the diameter of the mandibular incisive canal, should be verified by CBCT prior to performing implant surgery in the anterior mandibular area to prevent possible nerve damage.

Foreign body removal assisted by an intraoral ultrasound probe.

Ultrasonography has recently been applied to the field of oral and maxillofacial surgery because of its noninvasiveness and ease of use. However, traditional transducers are not used in the intraoral area because of their large size. A novel intraoral transducer was introduced with size, volume, and axis modifications. This new transducer allows the surgeon to approach the intraoral region during dental procedures. This report describes a case of successful removal of a foreign body using the newly developed intraoral ultrasound probe. Precise localization and minimally invasive removal of the foreign body using the intraoral transducer were simultaneously conducted. Because of its many advantages, this intraoral ultrasound transducer has the potential to be applied in oral and maxillofacial surgery.

The relationship between masseter muscle thickness measured by ultrasonography and facial profile in young Korean adults.

PURPOSE: The purpose of this study was to evaluate the relationship between masseter muscle thickness, facial morphology, and mandibular morphology in Korean adults using ultrasonography. MATERIALS AND METHODS: Ultrasonography was used to measure the masseter muscle thickness bilaterally of 40 adults (20 males, 20 females) and was performed in the relaxed and contracted states. Facial photos and panoramic radiography were used for morphological analyses and evaluated for correlations with masseter muscle thickness. We also evaluated the correlations of age, body weight, stature, and body constitution with masseter muscle thickness. RESULTS: In the relaxing, the masseter was 9.8±1.3 mm in females and 11.3±1.2 mm in males. In the contracted state, it was 12.4±1.4 mm in females and 14.7±1.4 mm in males. Facial photography showed that bizygomatic facial width over facial height was correlated with masseter muscle thickness in both sexes in the relaxed state, and was statistically significantly correlated with masseter muscle thickness in males in the contracted state. In panoramic radiography, correlations were found between anterior angle length and posterior angle length and masseter muscle thickness in females, and between body length and posterior angle length, between anterior angle length and body length, between ramal length and body length, and between body length and condyle length in males. CONCLUSION: Masseter muscle thickness was associated with facial and mandibular morphology in both sexes, and with age in males. Ultrasonography can be used effectively to measure masseter muscle thickness.

Long-Term Stability of Pre-Orthodontic Orthognathic Bimaxillary Surgery Using Intraoral Vertical Ramus Osteotomy Versus Conventional Surgery.

PURPOSE: The aim of the present study was to compare the long-term stability of bimaxillary surgery using an intraoral vertical ramus osteotomy (IVRO) with and without presurgical orthodontic treatment. MATERIALS AND METHODS: The present retrospective study included 31 consecutive patients with skeletal Class III malocclusions who had undergone bimaxillary surgery (Le Fort I osteotomy and bilateral IVRO). Patients were divided into 2 groups based on treatment type: pre-orthodontic orthognathic surgery (POGS; n = 17) and conventional surgery with presurgical orthodontic treatment (CS; n = 14). Lateral cephalograms were obtained before surgery, 1 day after surgery, 1 month after surgery, 1 year after surgery, and 2 years after surgery to evaluate skeletal and soft tissue changes between the 2 groups. Data were analyzed using χ2 tests, Mann-Whitney U tests, repeated-measures analyses of variance, and independent t tests. RESULTS: There was no significant difference in skeletal or soft tissue measurements-with the exception of the angle between the sella-and-nasion plane and the occlusal plane (SN-OP; P < .001)-between the CS and POGS groups at 2 years after IVRO. The SN-OP had increased in the CS group but decreased in the POGS group at 2 years after surgery. CONCLUSIONS: These findings suggest that POGS and CS have similar long-term stability in patients with skeletal Class III malocclusion.

Creating protective appliances for preventing dental injury during endotracheal intubation using intraoral scanning and 3D printing: a technical note.

Digital dentistry has influenced many dental procedures, such as three-dimensional (3D) diagnosis and treatment planning, surgical splints, and prosthetic treatments. Patient-specific protective appliances (PSPAs) prevent dental injury during endotracheal intubation. However, the required laboratory work takes time, and there is the possibility of tooth extraction while obtaining the dental impression. In this technical report, we utilized new digital technology for creating PSPAs, using direct intraoral scanners and 3D printers for dental cast fabrication.

Prevalence of proximal contact loss between implant-supported fixed prostheses and adjacent natural teeth and its associated factors: a 7-year prospective study.

OBJECTIVES: The aim was to analyze the prevalence rate of proximal contact loss (PCL) between implant-fixed prostheses (IFPs) and adjacent teeth and investigate the associated factors. MATERIAL AND METHODS: One hundred fifty participants were recruited for this prospective study from January 2009 to December 2014. Two hundred thirty-four IFPs supported by 384 implants for the posterior region were followed up until June 2016. The contact tightness had been recorded using aluminum strips of different thicknesses with a regular interval after delivery. Proximal contact was considered as lost if the contact tightness was over 50 µm, and statistical analyses were performed to estimate the prevalence rate of PCL and its influential factors. RESULTS: Among the total 299 proximal contacts of 234 IFPs, 179 were observed as a PCL (59.9%). Bone level and root configuration of the adjacent teeth, the proximal contact position and jaw position of the implant prostheses were statistically significant factors, when analyzed by the cumulative PCL rate using the log-rank test of the Kaplan-Meier method (P < 0.05) According to the Cox proportional hazard regression analysis, the proximal contact position, bone level of adjacent teeth and jaw position were revealed to be statistically significant (P < 0.05). CONCLUSION: PCL should be considered an implant prosthesis complication to which various associated factors could be related. This study revealed that the lower alveolar bone support level of the adjacent teeth, maxillary position of IFPs and mesial site of IFPs were significantly associated with a higher incidence of PCL.

Parathyroid Hormone (1-34) Might Not Improve Early Bone Healing after Sinus Augmentation in Healthy Rabbits.

Purpose. This study evaluated the effect of administering intermittent parathyroid hormone [PTH (1-34), henceforth PTH] on the early-stage bone healing of maxillary sinus augmentation in healthy rabbits. Materials and Methods. Bovine bone mineral was grafted on the sinuses of 20 female New Zealand white rabbits. The animals were randomly divided into two groups, PTH (n = 10) or saline (n = 10), in which either PTH or saline was injected subcutaneously 5 days a week for 2 weeks. Half of the animals in each group were killed at 2 weeks postoperatively and the other half were killed at 4 weeks postoperatively. The dosage of PTH was 10 µg/kg/day. Radiographic and histomorphometric analyses were performed. Result. The new bone area (NBA) did not differ significantly between the PTH and saline groups. The NBA in the PTH group in the total augmented area and in the demarcated window, center, and Schneiderian membrane regions increased significantly from 2 to 4 weeks. The number of osteoclasts decreased significantly from 2 to 4 weeks in both groups, with no difference between the two groups. Conclusion. Intermittent PTH might not stimulate new bone formation in healthy rabbits during the first 4 weeks of healing.

Changes in the craniofacial complex and alveolar bone height of young adults: Applications to dental medicine.

The few studies on craniofacial complex changes in adults have reported contradictory findings. The aim of this study was to radiographically evaluate changes in the craniofacial complex and alveolar bone height of young adults over a 4-year period. This prospective study included 82 young adults (62 men; mean age, 19.0 ± 0.8 years; 20 women; mean age, 18.8 ± 0.9 years). Three radiographic examinations were performed longitudinally: the first (T0) was conducted at the start of the study, the second (T1) was conducted 2 years later, and the third (T2) was conducted at the end of the study period. As part of these examinations, lateral cephalograms, maxillary and mandibular anterior periapical radiographs, and bilateral posterior bitewing radiographs were obtained. During the 4-year follow-up period, all linear cephalometric measurements were significantly greater in men than in women. The amount of increase in the anterior facial height between T1 and T2 was lower in women than in men (P = 0.029). The rate of uprighting of the upper incisors was lower in men than in women over time (P = 0.020). The apex of the nose moved inferiorly between T0 and T2 (P = 0.006). The average overall change in the alveolar bone height was 0.27 mm and the yearly change was 0.07 mm over the 4-year period (P< 0.001). Significant changes in the skeletal, dental, and soft tissue, as well as, natural changes in alveolar bone, occur in young adults over time. Clin. Anat. 29:1011-1017, 2016. © 2016 Wiley Periodicals, Inc.