YAP1 regulates esophageal stem cells' self-renewal and differentiation.

Esophageal epithelium is one of the most proliferative and regenerative epithelia in our body, indicating robust stem cell activity. However, the underlying mechanisms regulating the self-renewal and differentiation of esophageal stem cells need to be more elucidated. Here, we identify the role of YAP1 in esophageal stem cells. YAP1 is differentially expressed in the nuclei of esophageal basal cells. Furthermore, the treatment of verteporfin, a YAP1 inhibitor, interfered with esophageal organoid formation. Consistently, YAP1 deletion decreased esophageal organoid formation and the expression of basal genes while increasing the expression of suprabasal genes. Finally, global transcriptomic analysis revealed that YAP1 inhibition induced a significant enrichment of gene sets related to keratinization and cornification, while depleting gene sets related to DNA repair and chromosome maintenance. Our data uncover a novel regulatory mechanism for esophageal stem cells, which could provide a potential strategy for esophageal regenerative medicine.

Three-dimensional evaluation of dentopalatal changes after rapid maxillary expansion in growing children.

INTRODUCTION: In growing children with transverse malocclusion problems, various types of rapid maxillary expanders (RMEs) have been effectively used in skeletal and dental expansions. We evaluated 3-dimensional dentopalatal changes in growing children who underwent maxillary expansion using RMEs and bonded RMEs. METHODS: We investigated dentopalatal changes in 20 patients treated with bonded RMEs, 19 with RMEs, and 38 control patients. Dental plaster models before and after expansion were scanned 3-dimensionally and superimposed to evaluate transverse expansion, expansion ratio, angular expansion, and palatal expansion height ratio. RESULTS: Using bonded RMEs, similar anterior and posterior dental expansions were achieved with an efficiency of 69%-76% (expansion ratio), and palatal soft-tissue expansion occurred more apically in the posterior area (palatal expansion height ratio, 1.00) than in the anterior area (palatal expansion height ratio, 0.64). Using RMEs, a larger posterior dental expansion was achieved, with an efficiency of 106%-117% (expansion ratio), than anterior dental expansion (55%-60%), and palatal soft-tissue expansion occurred more apically in the posterior area (palatal expansion height ratio, 0.99) than anterior area (palatal expansion height ratio, 0.23). CONCLUSIONS: Dental expansions in the anterior and posterior areas were similar using bonded RMEs, whereas the posterior dental expansions were larger than those of the anterior area using RMEs. The entire palatal soft-tissue slope expanded in the posterior area, whereas the occlusal part expanded in the anterior area using RMEs and bonded RMEs.

Surgical vs nonsurgical treatments in patients with anterior open-bite have similar effects in occlusal function: A 2-year follow-up study.

INTRODUCTION: This study aimed to investigate changes in bite force (BF) and occlusal contact area after anterior open-bite (AOB) treatment and compare the changes in surgical vs nonsurgical treatment. METHODS: This retrospective study included patients with AOB compared with normal occlusion. AOB was corrected by either intrusion of the maxillary molars (intrusion group, n = 19) or orthognathic surgery (surgery group, n = 37). The control group (n = 35) had a normal overbite relationship. Records of lateral cephalograms, BF, and occlusal contact area taken before (T0), immediately after (T1), and 2 years after (T2) orthodontic treatment were compared within and among the 3 groups. RESULTS: The open-bite group, including intrusion and surgery groups, had a lower BF and less occlusal contact area than the control group at T0 and T1 (P <0.001). However, there were no significant differences among the 3 groups at T2 (P >0.05). The intrusion and surgery groups showed no significant differences throughout the observation period extending from T0 to T2 (P >0.05). Although BF and occlusal contact area decreased at T1 compared with T0, they increased during retention and showed higher values at T2 than at T0. CONCLUSIONS: Treatment of AOB improved BF and occlusal contact area 2 years posttreatment. Orthognathic surgery and molar intrusion using orthodontic miniscrews can improve occlusal function similarly. Orthodontists can select either method depending on malocclusion severity and patient demand.

Treatment outcome comparison of Invisalign vs fixed appliance treatment in first premolar extraction patients.

INTRODUCTION: In this study, we compared the dentitional changes after Invisalign and conventional orthodontic treatment with 4 first premolar extractions. METHODS: This retrospective study included 57 patients whose orthodontic treatment involved the extraction of 4 first premolars because of bialveolar protrusion. A total of 27 patients were treated with Invisalign (mean age, 25.5 ± 5.2 years) and 30 patients with the fixed appliance (mean age, 24.4 ± 5.8 years). The angular and linear changes of the maxillary and mandibular central incisors, second premolars, first molars, and second molars were measured from the recordings on the basis of the lateral cephalograms taken before and after treatment. The angular changes of the canines and second premolars were measured using panoramic radiographs. RESULTS: The overbite and interincisal angle increased significantly in the Invisalign group compared with in the conventional fixed appliance group (P <0.05). The maxillary central incisors showed increased lingual tipping in the Invisalign group (P <0.05), whereas there was no statistically significant difference in the angular change of the mandibular incisors between groups (P >0.05). The maxillary first and second molars showed mesial tipping in the Invisalign group (P <0.05). The maxillary second premolars, first and second molars, and the mandibular second molars showed mesial movement in the Invisalign group (P <0.05). CONCLUSIONS: The Invisalign group showed more statistically significant lingual tipping of the maxillary central incisors, distal tipping of the maxillary canines, and mesial tipping of the maxillary first and second molars after maximum retraction of the anterior teeth compared with the fixed appliance group.

Association among craniofacial morphology, ethnicity, and risk of pediatric sleep-related breathing disorders: A multicenter study.

INTRODUCTION: Craniofacial morphology and ethnicity may be risk factors for sleep-related breathing disorder (SRBD) in children but have not yet been assessed in an international multicenter study. The objectives of this study were to assess the association among craniofacial features, self-reported ethnicity, and risk of SRBD in children undergoing orthodontic treatment. METHODS: Children aged 5-18 years who presented for orthodontic evaluation were enrolled in the United States, South Africa, South Korea, Saudi Arabia, and Japan. The risk of SRBD was defined as answering ≥0.33 positive responses to the Pediatric Sleep Questionnaire. Craniofacial features included measurements in sagittal and vertical dimensions to evaluate the cranial base, maxillomandibular and dental relationships, and nasopharyngeal airway dimensions. Logistic regression was performed to assess the association among craniofacial features, ethnicity, age, body mass index, and risk of SRBD. RESULTS: Data were obtained from 602 patients from 5 sites. A total of 76 patients (12.6%) had a risk of SRBD. The mean age was 12.5 years. Male gender (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.0-3.4; P = 0.041), Middle Eastern ethnicity (OR, 10.2; 95% CI, 4.1-25.4; P = 0.001), body mass index (OR, 1.1; 95% CI, 1.04-1.10; P = 0.001), gonial angle (OR, 0.91; 95% CI, 0.85-0.98; P = 0.011), and inferiorly positioned hyoid (OR, 1.1; 95% CI, 1.0-1.2; P = 0.002) were significantly associated with the risk of SRBD. CONCLUSIONS: In an ambidirectional cohort study across 5 sites, male gender, Middle Eastern ethnicity, body mass index, gonial angle, and inferiorly positioned hyoid were associated with the risk of SRBD in children undergoing orthodontic treatment.

Can medication-related osteonecrosis of the jaw be attributed to specific microorganisms through oral microbiota analyses? A preliminary study.

BACKGROUND: Medication-related osteonecrosis of the jaw (MRONJ) can cause significant pain and loss of aesthetics and function if not treated properly. However, diagnosis still relies on detailed intraoral examinations and imaging. Prognosis varies even among patients with similar stages or conditions of MRONJ, emphasizing the need for a deeper understanding of its complex mechanisms. Thus, this study aimed to identify the oral microbiota of patients with MRONJ. METHODS: This single-center prospective cohort study included patients with confirmed MRONJ who visited the Department of Oral and Maxillofacial Surgery at Yonsei University Dental Hospital between 2021 and 2022. Oral swab samples were collected from the affected and unaffected sides of each patient. The composition and enumeration of the microbial communities were analyzed, and the diversity was compared to verify ecological changes in the groups using a next-generation sequencing-based 16S metagenomic analysis. A statistical analysis was performed using Wilcoxon signed-rank test with SPSS version 22, and values of P less than 0.05 were considered statistically significant. RESULTS: The final study sample included 12 patients. The mean age was 82.67 ± 5.73 (range, 72-90) years. Changes in microbial composition were observed at different taxonomic levels (phylum, genus, and species). The identified microorganisms were commonly associated with periodontitis, gingival disease, and endodontic infection, suggesting a multifactorial etiology of MRONJ. CONCLUSIONS: Although this study is based on a small number of cases, it shows that MRONJ is not caused by a specific microorganism but can rather be caused by a variety of factors. By addressing these findings in large-scale studies, the significance of oral microbiome in pathogenesis can be further elucidated and can facilitate the development of effective therapeutic interventions for patients with MRONJ.

Changes in condylar position during orthodontic treatment depending on the amount of incisor retraction: a cone-beam computed tomography study.

OBJECTIVES: Orthodontic treatment may be associated with temporomandibular disorders through changes in the condylar position. This study aimed to evaluate changes in the condylar position among different amounts of maxillary incisor retraction during orthodontic treatment using cone-beam computed tomography images. MATERIALS AND METHODS: Fifty-four participants were enrolled and divided into minimal (n = 14), moderate (n = 20), and maximal (n = 20) retraction groups based on the amount of incisor retraction (< 1, 1-6, and > 6 mm, respectively). Changes in condylar position before (T0) and after (T1) orthodontic treatment were assessed for the superior, anterior, posterior, and medial joint spaces (SJS, AJS, PJS, and MJS, respectively). Changes in joint spaces were compared between T0 and T1 in each group using paired t-tests and among the three groups using analysis of variance. RESULTS: Anterior movement of the condyle was observed in the maximal retraction group with a 0.2 mm decrease in ΔAJS and a 0.2 mm increase in ΔPJS, significantly greater than those in the minimal retraction group. The AJS and PJS showed statistically significant differences between T0 and T1 (P < 0.05) in the maximal retraction group. CONCLUSIONS: The condyle may show a statistically significant but clinically insignificant forward movement in the maximal incisor retraction group, whereas it was relatively stable in the minimal and moderate incisor retraction groups. CLINICAL RELEVANCE: More attention should be paid to the signs and symptoms of the condyle in patients with excessive incisor retraction during orthodontic treatment.

Correlation of masticatory muscle activity and occlusal function with craniofacial morphology: a prospective cohort study.

OBJECTIVES: Masticatory function, including masticatory muscle activity and occlusal function, can be affected by craniofacial morphology. This study aimed to investigate the relationship between craniofacial morphology and masticatory function in participants who had completed orthodontic treatment at least two years before and had stable occlusion. MATERIALS AND METHODS: Fourty-two healthy participants were prospectively enrolled and divided into three vertical cephalometric groups according to the mandibular plane angle. Masticatory muscle activity (MMA) in the masseter and anterior temporalis muscles was assessed using surface electromyography. The occlusal contact area (OCA) and occlusal force (OF), defined as occlusal function in this study, were evaluated using occlusal pressure mapping system. Masticatory muscle efficiency (MME) was calculated by dividing MMA by OF. The craniofacial morphology was analyzed using a lateral cephalogram. The masticatory function was compared using one-way analysis of variance. Pearson correlations were used to assess relationships between craniofacial morphology and masticatory function. RESULTS: The hypodivergent group had the lowest MMAand the highest MME in the masseter (167.32 ± 74.92 µV and 0.14 ± 0.06 µV/N, respectively) and anterior temporalis muscles (0.18 ± 0.08 µV/N, p < 0.05). MMA in the masseter showed a positive relationship with mandibular plane angle (r = 0.358), whereas OCA (r = -0.422) and OF (r = -0.383) demonstrated a negative relationship (p < 0.05). The anterior temporalis muscle activity negatively correlated with ramus height (r = -0.364, p < 0.05). CONCLUSIONS: Vertical craniofacial morphology was related to masticatory function. Hypodivergent individuals may have low MMA and high occlusal function, resulting in good masticatory muscle efficiency. CLINICAL RELEVANCE: Hypodivergent individuals require careful consideration in orthodontic diagnosis and prosthetic treatment planning.

Changes in masticatory performance during the retention period following 4-premolar extraction and non-extraction orthodontic treatment.

OBJECTIVES: To evaluate changes in masticatory performance (MP) during the retention period after extraction and non-extraction treatment and compare it with MP in individuals with normal occlusion. MATERIALS AND METHODS: Adult patients who had completed orthodontic fixed appliance treatment comprised the extraction and non-extraction treatment groups, and those with normal occlusion comprised the control group. Their mixing ability (MA), maximum bite force (MBF), and occlusal contact area (OCA) were recorded immediately after the fixed appliance was removed and at 1 month, 6 months, and 1 year post-treatment. The MA was measured via the two-color chewing gum MA test using ViewGum software, and the MBF and OCA were measured using Dental Prescale II system. RESULTS: MA immediately after orthodontic treatment was lower than that in the normal group but showed a time-dependent gradual increase during a 1-year retention period (P < 0.01). The MA at 1 month post-treatment was not significantly different between the three groups (P > 0.05). The MA revealed a significant correlation with the MBF and OCA (P < 0.01). CONCLUSIONS: The MP immediately after orthodontic treatment was lower than that in the normal group but increased gradually, with levels comparable to those of the normal occlusion group at 1 month post-treatment. Further, extraction did not affect the recovery of the MP after orthodontic treatment. CLINICAL RELEVANCE: No other study has evaluated the changes in MP during the retention period after orthodontic treatment. The findings show that compared with MBF and OCA, the patients' MP improved faster to levels found in normal occlusion.

Evaluation of the dimensional alternation of the alveolar bone in patients with a congenitally missing mandibular lateral incisor using cone-beam computed tomography.

INTRODUCTION: The alveolar bone is an essential consideration when planning treatment for patients with tooth agenesis. This study evaluated the changes in the alveolar bone and adjacent teeth in patients with a congenitally missing mandibular lateral incisor using cone-beam computed tomography. METHODS: Twenty-three nonorthodontically treated adults with a unilateral congenitally missing mandibular lateral incisor were the missing group (M group). The control group (C group) consisted of 23 nonorthodontically treated adults with normal occlusion and no missing teeth. First, the difference in the arch perimeter between the groups was compared at the cementoenamel junction (CEJ) level and the root apex (RA) level. Next, the root divergence of the anterior teeth in the M group was observed. Finally, the alveolar bone thickness ratio was compared between the M and C groups at different vertical levels. RESULTS: The arch perimeter was significantly decreased in the M group at the CEJ and RA levels (P <0.05). Root divergence was observed adjacent to the missing site (P <0.0001). There were a reduction in total and cancellous cortical alveolar bone thickness (ABT) ratios at the 3-, 6-, and 9-mm positions (P <0.05). The buccal cortical ABT ratios decreased at the 3-and 6-mm positions. The lingual ABT ratio increased at the 9-mm position (P <0.05). CONCLUSIONS: The congenitally missing mandibular lateral incisor caused a reduction in the arch perimeter in the CEJ area and the RA area. The root divergences were observed in the teeth adjacent to the missing areas. A significant decrease in the buccal cortical bone and cancellous bone was observed in the missing area.