Fully automated deep learning approach to dental development assessment in panoramic radiographs.

BACKGROUND: Dental development assessment is an important factor in dental age estimation and dental maturity evaluation. This study aimed to develop and evaluate the performance of an automated dental development staging system based on Demirjian's method using deep learning. METHODS: The study included 5133 anonymous panoramic radiographs obtained from the Department of Pediatric Dentistry database at Seoul National University Dental Hospital between 2020 and 2021. The proposed methodology involves a three-step procedure for dental staging: detection, segmentation, and classification. The panoramic data were randomly divided into training and validating sets (8:2), and YOLOv5, U-Net, and EfficientNet were trained and employed for each stage. The models' performance, along with the Grad-CAM analysis of EfficientNet, was evaluated. RESULTS: The mean average precision (mAP) was 0.995 for detection, and the segmentation achieved an accuracy of 0.978. The classification performance showed F1 scores of 69.23, 80.67, 84.97, and 90.81 for the Incisor, Canine, Premolar, and Molar models, respectively. In the Grad-CAM analysis, the classification model focused on the apical portion of the developing tooth, a crucial feature for staging according to Demirjian's method. CONCLUSIONS: These results indicate that the proposed deep learning approach for automated dental staging can serve as a supportive tool for dentists, facilitating rapid and objective dental age estimation and dental maturity evaluation.

Correlation between dental and skeletal maturity in Korean children based on dental maturity percentile: a retrospective study.

BACKGROUND: The correlation between dental maturity and skeletal maturity has been proposed, but its clinical application remains challenging. Moreover, the varying correlations observed in different studies indicate the necessity for research tailored to specific populations. AIM: To compare skeletal maturity in Korean children with advanced and delayed dental maturity using dental maturity percentile. DESIGN: Dental panoramic radiographs and cephalometric radiographs were obtained from 5133 and 395 healthy Korean children aged between 4 and 16 years old. Dental maturity was assessed with Demirjian's method, while skeletal maturity was assessed with the cervical vertebral maturation method. Standard percentile curves were developed through quantile regression. Advanced (93 boys and 110 girls) and delayed (92 boys and 100 girls) dental maturity groups were defined by the 50th percentile. RESULTS: The advanced group showed earlier skeletal maturity in multiple cervical stages (CS) in both boys (CS 1, 2, 3, 4, and 6) and girls (CS 1, 3, 4, 5, and 6). Significant differences, as determined by Mann-Whitney U tests, were observed in CS 1 for boys (p = 0.004) and in CS 4 for girls (p = 0.037). High Spearman correlation coefficients between dental maturity and cervical vertebral maturity exceeded 0.826 (p = 0.000) in all groups. CONCLUSION: A correlation between dental and skeletal maturity, as well as advanced skeletal maturity in the advanced dental maturity group, was observed. Using percentile curves to determine dental maturity may aid in assessing skeletal maturity, with potential applications in orthodontic diagnosis and treatment planning.

Criteria for early diagnosis of mandibular third molar agenesis based on the developmental stages of mandibular canine, first and second premolars, and second molar: a retrospective cohort study.

BACKGROUND: Permanent first molars with severe dental caries, developmental defects, or involved in oral pathologies are at risk of poor prognosis in children. Accordingly, using the third molar to replace the first molar can be a good treatment option when third molar agenesis is predicted early. Thus, this retrospective cohort study aimed to develop criteria for early detection of mandibular third molar (L8) agenesis based on the developmental stages of mandibular canine (L3), first premolar (L4), second premolar (L5), and second molar (L7). METHOD: Overall, 1,044 and 919 panoramic radiographs of 343 males and 317 females, respectively, taken between the ages of 6 and 12 years were included. All developmental stages of L3, L4, L5, L7, and L8 were analyzed based on the dental age, as suggested by Demirjian et al. The independent t-test was used to assess age differences between males and females. The rank correlation coefficients were examined using Kendall's tau with bootstrap analysis and Bonferroni's correction to confirm the teeth showing developmental stages most similar to those of L8s. Finally, a survival analysis was performed to determine the criteria for the early diagnosis of mandibular third molar agenesis. RESULTS: Some age differences were found in dental developmental stages between males and females. Correlation coefficients between all stages of L3, L4, L5, and L7 and L8 were high. In particular, the correlation coefficient between L7 and L8 was the highest, whereas that between L3 and L8 was the lowest. CONCLUSION: If at least two of the following criteria (F stage of L3, F stage of L4, F stage of L5, and E stage of L7) are met in the absence of L8 crypt, agenesis of L8 can be confirmed.

Clinical Considerations for Dental Management of Children with Molar-Root Incisor Malformations.

Molar root-incisor malformation (MRIM) or molar-incisor malformation (MIM) is a new type of dental anomaly characterized by dysplastic roots of permanent first molars, occasionally second primary molars, and the crowns of maxillary central incisors. MRIM involving permanent first molars and second primary molars is characterized by normal crowns with short, thin, and narrow roots, whereas MRIM involving permanent maxillary central incisors exhibits constrictions of the crown in the cervical area. In the first case, we extracted the affected first permanent molars at the optimal timing to minimize space deficiencies and induce space closure. In addition, composite resin restorations were performed on the anterior central incisors. In the second case, a mandibular lingual arch was used to stabilize the affected teeth in order to mitigate discomfort by reducing rotational biting forces.

Prediction of agenesis of the maxillary second premolar based on the developmental stages of the maxillary canine, first premolar, and second molar.

OBJECTIVE: This study aimed to suggest criteria for the early diagnosis of agenesis of the maxillary second premolars (U5) based on the developmental stages of the maxillary canines (U3), first premolars (U4), and second molars (U7). DESIGN: Overall, 303 control patients and 72 patients with agenesis who met the inclusion criteria were analyzed among 5136 patients aged 5-11 years for whom panoramic radiographs were obtained at Seoul National University Dental Hospital from June 2008 to December 2009. All developmental stages of U3, U4, U5, and U7 in both groups were evaluated and categorized into the stages proposed by Demirjian et al. To confirm the delayed dental development in the agenesis group, the Wilcoxon rank sum test was used. For verifying the tooth with the most similar developmental pattern to U5, the Kendall tau Rank Correlation and Bootstrap methods were used. Moreover, survival analysis and leave-one-out-cross-validation were performed to identify the earliest developmental stages of U3, U4, and U7 at which agenesis of U5 can be confirmed. RESULTS: The developmental stage of U4 in the agenesis group was significantly delayed compared with that in the control group at ages 5-10. All of the stages of U3, U4, and U7 showed high correlation coefficients with U5. CONCLUSION: U5 agenesis can be confirmed with high prediction accuracy when at least two of the three conditions are satisfied: U3, U4, and U7 in Demirjian stages E, D, and C, respectively.

Prediction of agenesis of the mandibular second premolar using the developmental stages of the mandibular canine, first premolar, and second molar.

OBJECTIVE: The aim in this study was to suggest a standard for early diagnosis of agenesis of the mandibular second premolars (L5) by estimating the developmental stages of the mandibular canines (L3), first premolars (L4), and second molars (L7). DESIGN: Among all 5136 pediatric patients aged 5-11 years who received panoramic radiographs between June 2008 and December 2009 at Seoul National University Dental Hospital, 215 control patients and 74 agenesis patients who met inclusion criteria were analyzed. The developmental stages of all L3, L4, L5, and L7 of control and agenesis patients were estimated using the method proposed by Demirjian. To identify the tooth (L3, L4, L7) with the developmental pattern most similar to that of L5, Kendall rank correlation coefficients and Bootstrap method were used. To verify that patients with agenesis of L5 show delayed development, Wilcoxon rank sum test was used. To identify the stages in which to diagnose agenesis of L5, we performed survival analysis. RESULTS: There was a significant correlation between the developmental stages of L3, L4, L7 and L5. The developmental stages of those three teeth in the agenesis group were delayed compared with those in the control group at certain ages. If the developmental stages of at least two of those three teeth reach Demirjian stage D without the calcification of L5, agenesis of L5 can be confirmed. CONCLUSIONS: Agenesis of L5 can be confirmed when two of the three teeth (L3, L4, L7) reach Demirjian stage D.

Morphological relationship analysis of impacted maxillary canines and the adjacent teeth on 3-dimensional reconstructed CT images.

OBJECTIVE: To examine whether there is a relationship between maxillary canine impaction and the morphologic characteristics of the maxillary dentition, especially the root of the lateral incisor. MATERIALS AND METHODS: In this study, we selected only patients with unilateral maxillary canine impaction to compare the morphologic characteristics of the dentition on the impaction side and the clinically normal eruption side. The sample size was decided to be 40 based on the pilot study. To minimize bias depending on sex and location of the maxillary canine impaction, we selected equal numbers (20) of boys and girls, and equal cases (20) of buccal impaction and palatal impaction. Under the aforementioned conditions, the mean age was 13.5 ± 2.3 years. The multislice spiral computed tomography images of these 40 subjects were converted into three-dimensional (3D) reconstructed images using the OnDemand 3D program (Cybermed Co, Seoul, Korea). Then we measured the morphologic characteristics of the individual teeth on the obtained 3D teeth images. RESULTS: Length and volume of the maxillary lateral incisor's roots were significantly smaller on the impaction side compared with the normal eruption side (P = 0.001 and P = 0.006, respectively). The width and volume of the canine's crown were significantly greater on the impaction side compared with the normal eruption side (P = 0.020 and P < .0001, respectively). CONCLUSION: These results might help to prove the hypothesis that the smaller-sized lateral incisor roots and greater-sized canine crowns are the influential etiologic factors in maxillary canine impaction.

Dental treatment under general anesthesia in an intellectually disabled child with intellectually disabled parents.

Children with an intellectual disability often demonstrate lack of cooperation during dental treatment and require behavioral management. A child with mild intellectual disability can be managed adequately using restraints and medication. However, in cases of profound intellectual disability, dental treatment under general anesthesia is usually required. In cases where the patient is an intellectually disabled child who has intellectually disabled parents, it is difficult to evaluate the patient's preoperative condition and to obtain consent for treatment under general anesthesia. Furthermore, they are unable to respond to emergencies after treatment. Therefore, dental treatment should be performed under general anesthesia with hospitalization for children with an intellectual disability. This case presents the dental treatment of an intellectually disabled child, who has intellectually disabled parents, and who required general anesthesia and hospitalization.

Clinical Usefulness of Proseal Laryngeal Mask Airway for Anesthesia during Dental Procedures in Children.

AIM: Although the Proseal laryngeal mask airway (PLMA) has been widely used in anesthesia, little is known about its clinical effectiveness during dental procedures. We describe the clinical feasibility of the PLMA for managing airways in the field of pediatric dentistry. . STUDY DESIGN: We reviewed the medical records of children who underwent airway management with the use of the PLMA from January 2011 to December 2012 at an outpatient facility at Seoul National Dental University Hospital. RESULTS: During the study period, the airways of 19 children were managed with the PLMA for dental procedures. During its placement, blood pressure and heart rate were stably maintained. There were no interruptions of the dental procedures. None of the children experienced oxygen desaturation or ventilation difficulty. In one patient, the PLMA was dislodged for a short time, but the problem was easily solved with repositioning. After transferring to the post-anesthetic care unit, there were no incidences of oxygen desaturation or vomiting. All of the children were discharged from the hospital without complications. CONCLUSION: The PLMA can be successfully used in airway management during dental treatment in children.

Who succeeds at dental school? Factors predicting students' academic performance in a dental school in republic of Korea.

The purpose of this study was to examine what cognitive and non-cognitive factors were responsible for predicting the academic performance of dental students in a dental school in the Republic of Korea. This school is one of those in Korea that now require applicants to have a bachelor's degree. In terms of cognitive factors, students' undergraduate grade point average (GPA) and Dental Education Eligibility Test (DEET) scores were used, while surveys were conducted to evaluate four non-cognitive measures: locus of control, self-esteem, self-directed learning, and interpersonal skills. A total of 353 students matriculating at Seoul National University School of Dentistry in 2005, 2006, 2007, and 2008 consented to the collection of records and completed the surveys. The main finding was that applicants who scored higher on internal locus of control and self-efficacy were more likely to be academically successful dental students. Self-directed learning was significantly associated with students ranked in the top 50 percent in cumulative GPA. However, students' interpersonal skills were negatively related to their academic performance. In particular, students' lack of achievement could be predicted by monitoring their first-year GPA. Therefore, the identification of those factors to predict dental school performance has implications for the dental curriculum and effective pedagogy in dental education.

Initial experience with dexmedetomidine for dental sedation in children.

Sedation of uncooperative children for dental treatment is difficult since treatment is mainly carried out inside the oral cavity. Dexmedetomidine (DEX), recently introduced into clinical practice, has little influence on respiratory system even at high doses. We present cases of patients who underwent dental treatment under sedation using DEX infusion. DEX at a dose of 1 microg/kg was administered over 10 min after intravenous cannulation. DEX was infused to maintain sedation level within the range of the Observer's Assessment of Alertness and Sedation (OAA/S) scale 3- 4 throughout dental treatments. They were successfully treated under DEX sedation without any complications. Their uncooperative behaviors were successfully managed under DEX sedation.

Interrelationship between the position of impacted maxillary canines and the morphology of the maxilla.

INTRODUCTION: The aim of this study was to examine whether there is a relationship between the position of impacted maxillary canines and the morphology of the maxilla. METHODS: The palatally impacted canine group included 18 boys and 27 girls with an average age of 12 years 9 months (±2 years 1 month). The buccally impacted canine group comprised 19 boys and 26 girls with an average age of 12 years 2 months (±1 year 4 months). Arch length/intermolar width × 100 was used as the value for comparison of maxillary arch shapes, and palatal vault depth/intermolar width × 100 was used to compare the shapes of palate between the 2 groups. Each category was directly measured from the diagnostic model. RESULTS: Both the arch length/intermolar width × 100 and the palatal vault depth/intermolar width × 100 formulas showed statistically significant differences (P <0.0001), indicating differences in the shape of maxillary arch and the palatal vault between the 2 groups. CONCLUSIONS: The shape of the maxillary arch was narrower and longer in the palatally impacted canine group compared with the buccally impacted canine group, and the palatally impacted canine group had a deeper palatal vault than did the buccally impacted canine group.

The position of maxillary canine impactions and the influenced factors to adjacent root resorption in the Korean population.

The purpose of this study was to evaluate the position and aspects of maxillary canine impactions in the Korean population and investigate its comparison with the previous reports, while aiding in the establishment of diagnosis and treatment planning by revealing the influential factors of root resorption associated with such impactions. The subjects of this study consisted of 186 teeth from 148 patients, who had visited Seoul National University Dental Hospital due to impacted canines and had taken computerized tomographic images and panorama radiographic images. As a result, maxillary canine impaction in the Korean population occurred 1.5 times more often in females (F:M = 89:59) than males. Regarding the position of impaction, there were three times more buccal impactions (B:P = 140:46) than palatal impactions. The occurrence of root resorption was as high as 49.5 per cent. In evaluating the influential factors affecting adjacent root resorption, the significance of the impacted angulation was insufficient (P = 0.652). However, the buccopalatal position (P < 0.0001) and mesiodistal placement (P = 0.006, 0.037) of the impacted tooth were determined to be significant factors. Therefore, the adjacent root resorption caused by impacted maxillary canines can be stated to exhibit a greater amount of resorption as the positional proximity of the canine crown and lateral incisor root increases.

Effect of collagenase and esterase on resin-dentin interface: a comparative study between a total-etch adhesive and a self-etch adhesive.

PURPOSE: To examine the effects of collagenase and esterase activity on the microtensile bond strength and nanoleakage at the resin-dentin interfaces of two adhesive systems: a total-etch adhesive (Single Bond 2: SB) and a self-etch adhesive (Clearfil SE Bond: SE). METHODS: Resin composites were bonded to the occlusal dentin surfaces of extracted human premolars with either SB or SE. The bonded teeth were sectioned into beams and assigned to one of four storage conditions: phosphate buffer solution (24 hours), phosphate buffer solution (4 weeks), collagenase solution (4 weeks), or esterase solution (4 weeks). Microtensile bond strength was evaluated and analyzed by two-way ANOVA. Failure mode was analyzed under SEM, and nanoleakage was examined with TEM. RESULTS: The bond strength of SE was superior to that of SB after 4-week storage in three aqueous solutions. Collagenase and esterase solutions did not decrease the bond strength of SB any more than the phosphate buffer solution (P > 0.05). In regard to SE, the bond strength after 4-week storage in collagenase solution was lower than in the phosphate buffer solution (P < 0.05). TEM images revealed increasing tendency of nanoleakage in the bonded interfaces after storage in collagenase and esterase solutions.

Long-term evaluation of the remineralization of interproximal caries-like lesions adjacent to glass-ionomer restorations: a micro-CT study.

PURPOSE: To compare the remineralization of incipient artificial interproximal caries in the presence of three glass-ionomer cements (highly-filled glass-ionomer cement, compomer, resin-modified glass-ionomer cement) and a resin composite (control). METHODS: Proximal restorations were simulated by placing tooth specimens and the various glass-ionomer cements in closed containers with artificial saliva at 37 degrees C and pH 7.0 for 30 days with constant circulation. Tomographic images were obtained with a micro CT scanner at 90, 180, and 270 days, and density-measuring software was used to calculate the micro-density of artificial caries lesions in the specimens. The mean density changes were compared between groups in order to evaluate the effects of remineralization. All data were analyzed using one-way ANOVA and the post-hoc Tukey multiple comparison test at P < 0.05. RESULTS: While the density of artificial caries lesions increased for all treatments, the increases for the three glass-ionomer groups were significantly higher than that for the resin group in each 3-month period. As time increased, the amount of density also increased for the glass-ionomer groups, and significant differences were found between the remineralization effects of the glass-ionomer groups. The micro CT proved to be an effective evaluation method.

Effect of acidulated phosphate fluoride (APF) gel on the adherence of cariogenic bacteria to resin composites.

PURPOSE: To evaluate the effect of 1.23% acidulated phosphate fluoride (APF) and the subsequent polishing on the in vitro adherence of mutans streptococci to resin composites in a model that simulated the oral cavity conditions. METHODS: Samples of light-curing resin-based composites (Z100 and Z250) were treated with 1.23% APF gel (Sultan) for 1 minute and polished subsequently with Sof-Lex disks. The bacterial adherence of Streptococcus mutans and Streptococcus sobrinus to the APF gel treated resin samples and the subsequent polished samples were analyzed and compared with the adherence to the non-treated controls. RESULTS: The 1.23% APF gel caused a significant increase in the adherence of Streptococcus mutans and Streptococcus sobrinus. The increasing rate of the bacterial adherence to resin composites after APF treatment ranged from 73.5% to 167% and differed according to the bacterial strains. A decrease in the adherence of the bacteria was found after subsequent polishing with Sof-Lex disks.

Mutational hot spot in the DSPP gene causing dentinogenesis imperfecta type II.

The current system for the classification of hereditary defects of tooth dentin is based upon clinical and radiographic findings and consists of two types of dentin dysplasia (DD) and three types of dentinogenesis imperfecta (DGI). However, whether DGI type III should be considered a distinct phenotype or a variation of DGI type II is debatable. In the 30 years since the classification system was first proposed, significant advances have been made regarding the genetic etiologies of inherited dentin defects. DGI type II is recognized as an autosomal dominant disorder with almost complete penetrance and a low frequency of de novo mutations. We have identified a mutation (c.52G-->T, p.V18F) at the first nucleotide of exon 3 of the DSPP (dentin sialophosphoprotein) gene in a Korean family (de novo) and a Caucasian family. This mutation has previously been reported as causing DGI type II in a Chinese family. These findings suggest that this mutation site represents a mutational "hot spot" in the DSPP gene. The clinical and radiographic features of these two families include the classic phenotypes associated with both DGI type II and type III. Finding that a single mutation causes both phenotypic patterns strongly supports the conclusion that DGI type II and DGI type III are not separate diseases but rather the phenotypic variation of a single disease. We propose a modification of the current classification system such that the designation "hereditary opalescent dentin" or "DGI type II" should be used to describe both the DGI type II and type III phenotypes.

Effect of ultrasonic vibration on dentin bond strength and resin infiltration.

PURPOSE: To apply a vibration technique to compare the bond strength and resin penetration depth into the dentin tubules with those gained using conventional techniques. METHODS: Eighty-eight noncarious extracted human permanent molar teeth were sectioned to remove the coronal enamel. They were embedded in a 1-inch PVC pipe with an acrylic resin. The occlusal surfaces were placed so that the tooth and the embedding medium were at the same level to form a single flat surface. The samples were subsequently polished with silicon carbide abrasive papers, and randomly assigned to four groups (n=22). In Groups 1 and 2, Single Bond was used, and in Groups 3 and 4, One-Step was used. Each adhesive system was applied according to its manufacturer's instructions. For Groups 2 and 4, vibration was applied with an ultrasonic scaler for 10 seconds, and the adhesive was light-cured for 10 seconds. The resin composite was condensed onto the prepared surface in two increments using a Teflon mold and each increment was light-cured for 40 seconds. After 24 hours soaking in tap water at room temperature, the specimens were thermocycled, and the shear bond strengths were measured using a universal testing machine. One-way ANOVA test followed by Student-Newman-Keuls test (P < 0.05) were used to analyze the results. To investigate the infiltration patterns of the adhesive materials, the surface of the specimens was examined with electron microscopy. RESULTS: The shear bond strengths of the vibration groups (Groups 2, 4) were significantly higher than those of the non-vibration groups (Groups 1, 3). The shear bond strengths of Single Bond and One-Step were not significantly different. The vibration groups showed greater numbers of resin tags in the tubules and lateral branches under SEM than the non-vibration groups.