Maxillary basal arch forms in operated adult patients with cleft lip and palate using root apices: A pilot study.

OBJECTIVES: The purpose was to identify the maxillary basal arch forms utilizing the root apices and compare the maxillary basal arch form of groups with cleft lip and palate (CLP) and normal group. MATERIALS AND METHODS: This study included 30 patients (21.8 ± 3.5 years old) with unilateral CLP (ULCP group) and 30 patients (20.9 ± 2.2 years old) with bilateral CLP (BCLP group). The normal group consisted of 30 non-cleft patients (21.2 ± 2.3 years old) with normal occlusion. Three-dimensional (3D) Cartesian coordinates of the root apices of each tooth were determined using cone-beam computed tomography. The 3D coordinates were projected onto the palatal plane to create the 2D coordinates. Thereafter, the basal arch forms were constructed by the Procrustes superimposition. Finally, For the basal arch form comparisons among groups, the inter-root widths were measured. RESULTS: Both CLP groups had a narrower inter-root width than the normal group. The BCLP group had significantly narrower premolar and molar widths than the UCLP group (P < .05). Especially, the inter-first molar width of the UCLP and BCLP groups was 3.7 ± 0.7 (P < .001) and 6.6 ± 0.8 (P < .001) mm smaller than that of the normal group, respectively. CONCLUSIONS: We used the root apices to identify the basal arch forms. The basal arch form of patients with CLP was narrower than that of the normal group. The basal arch form of patients with BCLP was narrower than that of patients with UCLP. Our findings may help clinicians better comprehend basal arch forms in patients with CLP and transverse discrepancies.

Comparison of root apex's position between unilateral and bilateral palatally impacted canines: A pilot study.

INTRODUCTION: The purpose was to determine whether the location of the root apices of unilateral palatally impacted canines differs from that of bilateral palatally impacted canines using cone-beam computed tomography. METHODS: The subjects were divided into 3 groups: a bilateral palatally impacted canine group (BPG; n = 28), a unilateral palatally impacted canine group (UPG; n = 28), and a control group (CG; n = 28) that included contralateral normally erupted canines in the UPG. After selecting the root apex in the onDemand3D program, 3-dimensional coordinates were extracted. These 3-dimensional coordinates were converted using the MATLAB program to 2-dimensional coordinates via projection on the palatal plane. Procrustes analysis was used to superimpose these 2-dimensional coordinates. The x- and y-coordinates of the root apices were used to measure the distance between the origin and root apex. RESULTS: The distance between the root apex of the canine and the origin was 17.43 ± 1.78 mm in BPG, 17.96 ± 1.87 mm in UPG, and 13.96 ± 0.95 mm in CG. There was no statistically significant difference between UPG and BPG. However, there was a statistically significant difference between the CG and impacted groups (UPG and BPG). The same results were found for the x- and y-coordinates. CONCLUSIONS: The location of the root apices of unilateral palatally impacted canines is similar to that of bilateral palatally impacted. The location of root apices of palatally impacted canines differs from that of normally erupted canines.

Melatonin Attenuates RANKL-Induced Osteoclastogenesis via Inhibition of Atp6v0d2 and DC-STAMP through MAPK and NFATc1 Signaling Pathways.

Melatonin is a hormone secreted by the pineal gland that is involved in the biorhythm of reproductive activities. The present study investigated the inhibitory effects of melatonin on osteoclastogenesis in RAW 264.7 cells according to changes in V-ATPase and the corresponding inhibition of the MAPK and NFATc1 signaling processes. METHODS: the cytotoxic effect of melatonin was investigated by MTT assay. Osteoclast differentiation and gene expression of osteoclast-related factors were confirmed via TRAP staining, pit formation assay, immunofluorescence imaging, western blot, and real-time PCR. RESULTS: melatonin was found to inactivate the p38 and JNK of MAP kinase in RAW264.7 cells treated with RANKL and treated with a combination RANKL and melatonin for 1, 3, and 5 days. The melatonin treatment group showed a reduction in osteoclastogenesis transcription factors and ATP6v0d2 gene expression. CONCLUSIONS: melatonin inhibits osteoclast differentiation and cell fusion by inhibiting the expression of Atp6v0d2 through the inactivation of MAPK and NFATc1 signaling in RANKL-stimulated RAW264.7 macrophages. The findings of the present study suggest that melatonin could be a suitable therapy for bone loss and imply a potential role of melatonin in bone health.

Anatomical relationship between the maxillary posterior teeth and the sinus floor according to an anterior overbite.

OBJECTIVE: To evaluate the vertical relationship between the maxillary sinus floor (MSF) and the maxillary posterior teeth (MPT) according to an anterior overbite. SETTINGS AND SAMPLE POPULATION: The patients were divided into three groups according to an anterior overbite. The open bite group (OBG) included patients with an anterior overbite of ≤0 mm, the normal overbite group (NBG) included patients with an overbite of 0-3 mm, and the deep bite group (DBG) included patients with an overbite ≥3 mm. Thirty patients were randomly matched into each group based on age and sex. MATERIALS AND METHODS: The distances and vertical relationship between the MSF and the MPT was analysed using cone-beam computer tomography. The vertical relationship between the two was classified as either favourable or unfavourable for the intrusion of the posterior teeth. RESULTS: A higher ratio of patients in the OBG had MPT positioned close to the MSF than the DBG. Intrusion of the posterior teeth was unfavourable for an average of 87.2%, 77.2% and 70.2% molars in the OBG, NBG and DBG, respectively. CONCLUSIONS: The vertical distance between the MSF and the MPT is associated with an anterior overbite. The posterior teeth were in an unfavourable position for the orthodontic intrusion in the OBG as compared to the other groups. Additional caution is needed when planning orthodontic intrusion treatment for patients with an anterior open bite. But, there were some individual variations within each group.

Comparison of maxillary basal arch forms using the root apex in adult women with different skeletal patterns: A pilot study.

INTRODUCTION: This study aimed to establish maxillary basal arch forms using the root apices and to determine the differences in the basal arch forms in adult women with different sagittal skeletal patterns. METHODS: This retrospective study included 91 adult women, with either a Class I (n = 24), Class II Division 1 (n = 22), Class II Division 2 (n = 23), or Class III (n = 22) malocclusion, who underwent cone-beam computed tomography. Three-dimensional coordinates of the root apices were determined using the multiplanar reformation mode of OnDemand3D software (Cybermed Inc, Seoul, South Korea). Two-dimensional coordinates were converted from acquired 3-dimensional coordinates via projection on the palatal plane, and the Procrustes superimposition method was used to build the basal arch form. Finally, interroot width measurements were performed for basal arch form comparisons. RESULTS: There were significant differences among the 4 groups (P <0.05) with respect to the intercanine width. The intercanine width of Class II Division 1 group was significantly narrower than that of the other groups. The Class II Division 1 and Class II Division 2 groups tended to have tapered arch forms and squared arch forms, respectively. CONCLUSIONS: We established maxillary basal arch forms using the root apices. The Class II Division 1 group had a significantly narrower intercanine distance. The use of the root apex to depict the basal arch form seems reasonable.

Preliminary Study to Determine the Reference Plane of Patients With a Unilateral Cleft Lip and Palate.

OBJECTIVE: The objective of this study was to determine the three-dimensional midsagittal reference planes for unilateral cleft lip and palate (UCLP) patients that can be easily applied in a clinical setting. DESIGN: This was a retrospective analysis. PATIENTS: There were 35 UCLP patients (25 men, 10 women; 28.1 ± 6.9 years old) in this study. METHODS: With landmark's three-dimensional coordinates obtained from cone-beam computed tomography, the symmetric midsagittal reference planes were calculated by applying the ordinary Procrustes superimposition method using the original and mirror images. Procrustes analysis was also used to find the closest landmarks to the calculated symmetric midsagittal reference plane and test its compatibility with the symmetrical midsagittal reference plane. MAIN OUTCOME MEASURE: The three nearest landmarks to the symmetric midsagittal reference plane were Opisthion, Basion, and Nasion. RESULTS: The averages of the sums of the squared Euclidean distance and squared Procrustes distance differences between the two configurations and shapes fabricated by the symmetrical and landmark-based midsagittal reference planes, respectively, were calculated as 1.836 ± 3.295 and 1.519 × 10-5 ± 2.351 × 10-5. CONCLUSION: It was confirmed that the midsagittal reference planes from these selected landmarks for UCLP patients were compatible with symmetric midsagittal reference planes from the Procrustes analysis and the asymmetric measurements.

Assessment of the root apex position of impacted maxillary canines on panoramic films.

INTRODUCTION: In this study, we aimed to analyze the root apex positions of impacted maxillary canines on panoramic radiographs according to their labiopalatal positions and to propose a new panoramic radiographic predictor of impacted maxillary canines. METHODS: Paired panoramic films and cone-beam computed tomography images of 104 patients with unilateral impacted maxillary canines were selected. The sector locations of the impacted canine root apices on the panoramic radiographs were compared with the labiopalatal positions of impacted maxillary canines on cone-beam computed tomography. Statistical correlations between panoramic and cone-beam computed tomography findings were examined with the chi-square test. RESULTS: A statistically significant association was observed between the sector locations of impacted canine root apices and the labiopalatal positions of the canines (P <0.001). The root apices of labially impacted canines were more frequently located in sector 2 (corresponding to the lateral incisor position), those of palatally impacted canines were more frequently located in sector 4 (corresponding to the first premolar), and those of midalveolus impacted canines were more frequently located in sector 3 (corresponding to the canine). CONCLUSIONS: On panoramic films, the root apices of palatally impacted canines tended toward the root apices of the maxillary first premolars, whereas those of labially impacted canines tended toward the root apices of the maxillary lateral incisors. Therefore, the sector locations of impacted canine root apices on panoramic radiographs could be used for the early prediction of maxillary canine impactions and determination of the labiopalatal positions of impacted canines.

How far is the root apex of a unilateral impacted canine from the root apices' arch form?

INTRODUCTION: The purpose of this study was to determine the arch form of the root apices of normally erupting teeth and then determine the differences in the location of the apex of impacted canines relative to normally erupting canines. In addition, we sought to determine whether the labiopalatal position of the impacted canines influences the position of the apices. METHODS: The study included 21 patients with unerupted canines that subsequently had a normal eruption, 21 patients with palatally impacted canines, 27 patients with labially impacted canines, and 17 patients with midalveolus impacted canines. Images were obtained using cone beam computed tomography, and the x, y, and z coordinates of the root apices were determined using Ondemand3D software (Cybermed Co., Seoul, Korea). Two-dimensional coordinates were converted from acquired 3-dimensional coordinates via projection on a palatal plane, and the Procrustes method was used to process the converted 2-dimensional coordinates and to draw the arch forms of the root apices. Finally, we measured the extent of root apex deviation from the arch forms of the root apices. RESULTS: Normally erupting canines showed that even though calcifications may be immature, their positions were aligned with a normal arch form. The root apices of the impacted canines were an average of 6.572 mm away from the root apices' arch form, whereas those of the contralateral nonimpacted canines were an average distance of 2.221 mm away, a statistically significant difference. The palatally impacted canines' root apices distribution tended toward the first premolar root apices. CONCLUSIONS: Incompletely calcified, unerupted teeth with a subsequent normal eruption showed a normal arch form of the root apices. The root apices of impacted canines were farther from the arch forms than were the nonimpacted canines. Also, the root apices of impacted canines in the palatal area showed distributions different from those of the other impacted canine groups.

Anomalous transport properties in boron and phosphorus co-doped armchair graphene nanoribbons.

Multi-element doping of graphene could potentially provide functionalities that are not available in the single-element doping approach, but it has not been actively studied so far. Carrying out first-principles calculations, we study the structural, electronic, and transport properties of B-P edge-co-doped armchair graphene nanoribbons (aGNRs). We find that the B, P-complex edge-doped aGNRs exhibit an n-type transport behavior, which is counterintuitive considering the p-type and bipolar characters of the corresponding B- and P-doped aGNRs, respectively. Moreover, we show that the n-type property of B, P co-doped aGNRs is superior to that of representative N-doped aGNRs in terms of preserving the valence band edge conductance spectrum. Analyzing the mechanisms, we demonstrate that the structural distortion rather than chemical valence induces the anomalous donor character of B, P co-doped aGNRs. We thus propose a systematic modification of GNR atomic structures via co-doping as a novel approach to control charge transport characteristics of GNRs.

Proximal Segment Changes After Bilateral Sagittal Split Ramus Osteotomy in Facial Asymmetry Patients.

PURPOSE: To investigate the 3-dimensional postoperative changes in the proximal segments in patients with facial asymmetry according to the anteroposterior skeletal patterns. MATERIALS AND METHODS: A total of 51 patients with facial asymmetry who had undergone Le Fort I osteotomy and sagittal split ramus osteotomy (SSRO) with rigid fixation were classified according to their anteroposterior skeletal patterns. Cone-beam computed tomography (CBCT) data were obtained before (T0) and 6 months (T1) after surgery. The position, angulation, and distance of the proximal segment were measured from the CBCT superimposition. RESULTS: Comparing the T0 and T1 CBCT data, almost no significant differences were found in the condylar head position in any of the groups (P > .05), except for the axial condylar head position on the deviated side in the skeletal Class I group (P < .05) and the sagittal condylar head position on the deviated side in the skeletal Class III group (P < .05). However, the changes in the coronoid process and ramus down varied (P < .05), and these movements were related to changes in the ramal plane. Comparing the deviated and nondeviated sides, significant differences were found only in the skeletal Class I group (P < .05). CONCLUSIONS: The most influential factors affecting differences between the deviated and nondeviated sides in patients with facial asymmetry after bilateral SSRO could be the direction of the surgical movement of the distal segment of the mandible rather than its extent.

Differences Among Deviations, Genders, and Observers in the Perception of Eye and Nose Asymmetry.

PURPOSE: This study investigated the degree and range of recognition of canting of the interpupillary line and deviation of the nose, which were regarded as "normal," "acceptable," and "needing surgical correction," according to different observer groups. MATERIALS AND METHODS: Four different groups (40 each for laypeople, dental students, general dentists, and orthodontists) rated 11 simulated asymmetric images with canted eyes and a deviated nose separately. The raters categorized each image as normal, socially "acceptable" and not requiring correction, or abnormal and would benefit from correction. Survival analysis was used to evaluate the scope of perception. RESULTS: The degree of recognition for eye-canting and nose deviation was 2.31 and 2.92, respectively. Eye-canting and nose deviation had lower degrees of recognition in the clockwise direction (2.13°) and on the left side (2.65°), respectively. Women showed a lower degree of the "upper limit of the acceptable range" for canted eyes, and men showed a lower "degree of recognition" and "upper limit of the acceptable range" for a deviated nose. Orthodontists showed a larger upper limit of the acceptable range for eye-canting (P < .001). CONCLUSIONS: The perceptions of asymmetry of canted eyes and deviated nose were affected by gender, direction of asymmetry, and observer groups.

Motor imagery training improves upper extremity performance in stroke patients.

[Purpose] The purpose of this study was to investigate whether motor imagery training has a positive influence on upper extremity performance in stroke patients. [Subjects and Methods] Twenty-four patients were randomly assigned to one of the following two groups: motor imagery (n = 12) or control (n = 12). Over the course of 4 weeks, the motor imagery group participated in 30 minutes of motor imagery training on each of the 18 tasks (9 hours total) related to their daily living activities. After the 4-week intervention period, the Fugl-Meyer Assessment-Upper Extremity outcomes and Wolf Motor Function Test outcomes were compared. [Results] The post-test score of the motor imagery group on the Fugl-Meyer Assessment-Upper Extremity outcomes was significantly higher than that of the control group. In particular, the shoulder and wrist sub-items demonstrated improvement in the motor imagery group. [Conclusion] Motor imagery training has a positive influence on upper extremity performance by improving functional mobility during stroke rehabilitation. These results suggest that motor imagery training is feasible and beneficial for improving upper extremity function in stroke patients.

Measuring cerebral hemodynamic changes during action observation with functional transcranial doppler.

[Purpose] The purpose of this study was to investigate the effects of action observation training (AOT) on cerebral hemodynamic changes including cerebral blood flow velocity (CBFV) and cerebral blood flow volume (CBFvol) in healthy subjects. [Subjects] Fifteen healthy subjects participated in this study. [Methods] All subjects were educated regarding AOT, and systolic peak velocity (Vs) as well as mean flow velocity (Vm) in the middle cerebral artery (MCA), anterior cerebral artery (ACA), and posterior cerebral artery (PCA) were evaluated using functional transcranial doppler with a 2-MHz probe, before and after performing AOT. [Results] Healthy subjects showed significant differences in Vs and Vm in the MCA, ACA, and PCA after AOT compared with those before AOT. [Conclusion] Our findings indicate that AOT has a positive effect in terms of an increase in CBFV and CBFvol in healthy subjects, since the brain requires more blood to meet the metabolic demand during AOT.

Effects of Action Observational Training on Cerebral Hemodynamic Changes of Stroke Survivors: A fTCD Study.

[Purpose] The purpose of this study was to investigate the effect of Action Observational Training (AOT) on cerebral hemodynamic changes, including cerebral blood flow velocity (CBFV) and cerebral blood flow volume (CBFvol) in healthy subjects and stroke survivors. [Subjects] This study had a cross-sectional design. Seven healthy subjects and six patients with a first-time stroke participated in this study. [Methods] All subjects were educated about AOT, and we measured their systolic peak velocity (Vs), mean flow velocity (Vm), pulsatility index (PI), and resistance index (RI) in the middle cerebral artery (MCA), the anterior cerebral artery (ACA), and the posterior cerebral artery (PCA), before and after performance of AOT, using Functional Transcranial Doppler (fTCD) with a 2-MHz probe. [Results] Both healthy subjects and stroke survivors showed significant improvements of Vs and Vm in MCA, ACA and PCA after AOT. [Conclusion] Our findings indicate that AOT increases CBFV in healthy subjects and stroke survivors, because the brain requires more blood in order to meet the metabolic demand of the brain during AOT.

The Effects of VR-based Wii Fit Yoga on Physical Function in Middle-aged Female LBP Patients.

[Purpose] The purpose of this research was to determine the effects of a virtual reality-based yoga program on middle-aged female low back pain patients. [Subjects and Methods] Thirty middle-aged female patients who suffered from low back pain were assigned to either a physical therapy program or a virtual reality-based yoga program for a period of four weeks. Participants could check their posture and weight bearing on a monitor as they shifted their weight or changed their postures on a Wii balance board. There were a total of seven exercise programs. A 30-minute, three times per week, virtual reality-based Wii Fit yoga program or trunk stabilizing exercise was performed, respectively. [Results] Repeated-measures analysis of covariance revealed significant differences in between pre- and post-training VAS, algometer, Oswestry low-back pain disability index (ODI), Roland Morris disability questionnaire (RMDQ), and fear avoidance beliefs questionnaire (FBQ) scores. The VAS, algometer, ODI, RMDQ, and FBQ scores showed significant differences in groups. Regarding the effect of time-by-group interaction, there were significant differences in VAS, ODI, ODI, and FBQ scores. [Conclusion] In conclusion, for middle-aged female patients who have low back pain, a virtual reality-based yoga program was shown to have positive effects on physical improvements, and this program can be employed as a therapeutic medium for prevention and cure of low back pain.

Effects of vertical positions of anterior teeth on smile esthetics in Japanese and korean orthodontists and orthodontic patients.

STATEMENT OF PROBLEM: The perception of a pleasing smile may differ between the countries in Asia or may be converging on a more internationally pleasing one. PURPOSE: The aim of this study was to evaluate the influence of vertical positions of anterior teeth on smile esthetics as assessed by Japanese and Korean orthodontists as well as by orthodontic patients. MATERIALS AND METHODS: A standard composite smile was constructed from different females' intraoral and extraoral photographs. Vertical positions of anterior teeth were modified digitally in 1-mm increments, from 5 mm upper lip coverage of the incisors to 5 mm gingival exposure. Using a visual analog scale, 41 Japanese orthodontists and 96 Japanese orthodontic patients, 25 Korean orthodontists, and 72 Korean orthodontic patients rated the attractiveness of 11 smiles with altered gingival displays. RESULTS: Overall, the Japanese and Korean raters assigned similar esthetic scores between the corresponding groups. The male orthodontic patients assigned higher scores to the smiles with upper lip coverage of the teeth than the corresponding females did in both countries. The female patients assigned clinically significant higher scores to the smiles from 2 mm upper lip coverage of the teeth to 0 mm gingival exposure in both countries. CONCLUSIONS: In both countries, the orthodontists and the female patients shared the similar preference in the smile evaluation of vertical positions of anterior teeth, whereas the male orthodontic patients were more tolerant of upper lip coverage of the anterior teeth than the orthodontists and the female patients. CLINICAL SIGNIFICANCE: This study proposes 0 mm to 2 mm of upper lip coverage of the teeth as a threshold of acceptability for esthetic smile evaluations in female orthodontic patients. For male orthodontic patients, the paper proposes negative gingival display as a threshold of acceptability for esthetic smile evaluations.

Three-dimensional evaluation of mandibular width after mandibular asymmetric setback surgery using sagittal split ramus osteotomy.

Objective: The study aimed to evaluate the changes in mandibular width after sagittal split ramus osteotomy (SSRO) in patients with mandibular asymmetric prognathism using cone-beam computed tomography (CBCT). Methods: Seventy patients who underwent SSRO for mandibular setback surgery were included in two groups, symmetric (n = 35) and asymmetric (n = 35), which were divided according to the differences in their right and left setback amounts. The mandibular width was evaluated three-dimensionally using CBCT images taken immediately before surgery (T1), 3 days after surgery (T2), and 6 months after surgery (T3). Repeated measures analysis of variance was applied to verify the differences in mandibular width statistically. Results: Both groups showed a significant increase in the mandibular width at T2, followed by a significant decrease at T3. No significant difference was observed between T1 and T3 in any of the measurements. No significant differences were found between the two groups (p > 0.05). Conclusions: After mandibular asymmetric setback surgery using SSRO, the mandibular width increased immediately but returned to its original width 6 months after surgery.

Three-dimensional evaluation of the pharyngeal airway space in patients with anterior open bite.

Objective: : This study aimed to three-dimensionally evaluate the pharyngeal airway space (PAS) of patients with anterior open bite (AOB) by using cone-beam computed tomography (CBCT) and compare the findings with those obtained in individuals with normal occlusion. Methods: : The open bite group (OBG, n = 25) consisted of patients with an anterior overbite of -3 mm or less, while the control group (n = 25) consisted of age- and sex-matched individuals with an anterior overbite of 1-3 mm, Angle Class I malocclusion (1° ≤ point A-nasion-point B angle ≤ 4°), and a normodivergent profile (22° ≤ Frankfort mandibular plane angle ≤ 28°). After the CBCT data were reconstructed into a three-dimensional image, the PAS was segmented into four parts, and the volume of each part was measured. Pharyngeal airway length (PAL) and the area and transverse width of the part showing minimal constriction were also measured. Pearson's correlation analysis was used to evaluate the correlation between changes in the PAS and the amount of anterior overbite. Results: : The OBG showed a significantly narrower airway space in the nasopharyngeal, hypopharyngeal, and total airway volumes. The OBG also showed a significantly smaller area and transverse width of the part with minimal constriction. The OBG showed a significantly longer PAL, but there was no correlation between the amount of anterior overbite and the changes in PAS. Conclusions: : The PAS was associated with AOB. Patients with AOB had a narrower PAS and a smaller part showing minimal constriction.

Effects of different distalization directions and methods on maxillary total distalization with clear aligners: a finite element study.

OBJECTIVES: To analyze the effects of maxillary tooth distalization by clear aligner (CA) treatment with variations in the angular direction of the distalization force, presence of attachments, and force-application method used. MATERIALS AND METHODS: A finite element model containing alveolar bone, dentition, and periodontal ligament was constructed. Analytical model groups were as follows: (1) distalization with buttons (without attachments), (2) buttons on canines (with attachments), (3) precision cuts on the canines (without attachments), and (4) precision cuts on the canines (with attachments). A distalization force of 1.5 N was applied to the button or precision cut at -30°, -20°, -10°, 0°, 10°, 20°, and 30° to the occlusal plane. RESULTS: As the direction of force approached +30°, the dentition inclined posteriorly. The posterior movement pattern was significantly influenced by the presence of an attachment and the direction of force, rather than the area where the force was applied. Distal inclination was dramatically reduced with attachments. A disengagement or deformation of the CA may reduce the distalization efficiency of the dentition or move the dentition in an inappropriate direction. CONCLUSIONS: Attachments for efficient distalization by the CA are necessary. The use of miniscrews in the direction of force parallel to the occlusal plane is more advantageous than the use of Class II elastics. Due to CA deformation, distalization with the button on the canines can be more effective for distal movement of the maxillary dentition.

Effects of buccal corridors on smile esthetics in Japanese and Korean orthodontists and orthodontic patients.

INTRODUCTION: The purpose of this study was to evaluate the influence of the size of buccal corridors on the assessment of attractive smile esthetics by Japanese and Korean orthodontists and orthodontic patients. METHODS: Buccal corridors were modified digitally from 0% to 25% compared with the inner intercommissural width. Using a visual analog scale, 41 Japanese and 25 Korean orthodontists, and 96 Japanese and 72 Korean orthodontic patients (15-29 years old) rated the attractiveness of 6 smiles with altered buccal corridors. The influence of the size of the buccal corridor on smile esthetics was assessed. RESULTS: Although there was no significant sex difference in judging the effects of buccal corridors for the Korean and Japanese orthodontists, significant sex differences were shown for the Japanese orthodontic patients. There were significant differences in the 6 levels of median esthetic scores for all groups: 0%, 5%, and 10% buccal corridors in the smiles tended to be preferred to the other smiles, to become clinically significant for all groups. The median esthetic score decreased to become clinically significant from 10% to 15% buccal corridors for all groups. CONCLUSIONS: Japanese and Korean orthodontists and orthodontic patients prefer narrow or medium buccal corridors to broad buccal corridors.