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

Objective@#This study aimed to three-dimensionally evaluate the pharyngeal airway space (PAS) of patients with anterior open bite (AOB) by using conebeam 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.

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

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.

Orthodontic intrusion treatment of mandibular anterior teeth in a periodontal patient with hyperdivergent skeletal pattern: 8-year follow-up

Patients who have extruded anterior teeth and deep bite with pathologic tooth migration, it is necessary not only periodontal treat-ment for reduce inflammation, but also orthodontic treatment for intrusion of anterior teeth. However, it is difficult to place the orthodontic brackets due to the deep bite, and there is a problem that the extrusion of the posterior teeth occurs more easily than the intrusion of the anterior teeth biomechanically. In particular, in patients with long face, relative intrusion of the anterior teeth by extrusion of the posterior teeth causes the clockwise rotation of the mandible and makes the facial profile worse. Therefore the biomechanical consideration and appliance design that can block these problems are required from the treatment plan. This is a patient who had a deep overbite with extruded anterior teeth, treated by treatment and intrusion of mandibular anterior teeth using cute brackes and miniscrews, and resulted in favorable maintenance during 8-year retention.

Temporary replacement of congenital missing incisors on mandible using temporary anchorage devices in growing patient: 2-year follow-up

Agenesis of permanent tooth in adolescent patients can be treated either by orthodontic treatment for space closure or by main-taining the space until implant restoration can be carried out in adult. However, gradual atrophy of alveolar bone width makes it dif-ficult to restore the prosthesis in the future or may cause unaesthetic results. Therefore, maintaining of not only the missing space but also the alveolar bone width should be considered. This case is a treatment whereby a temporary replacement of missing 2mandibular incisors in adolescent patient was carried out using 2 temporary anchorage devices (TADs). Two TADs were placed hori-zontally 2 - 3 mm below the top of alveolar ridge, and fixed with artificial teeth by stainless steel wires extended. During the 2 year follow-up, neither gingival inflammation nor loss of the TADs have occurred. In the radiographic evaluation, the growth of the adja-cent alveolar bone was not inhibited, and the width of the alveolar bone was maintained.

Immediate effects of mandibular posterior displacement on the pharyngeal airway space: A preliminary study / 대한치과교정학회지

OBJECTIVE@#This study aimed to evaluate the immediate effects of mandibular posterior displacement on the pharyngeal airway space (PAS) by using cephalometric evaluations and to investigate how the surrounding structures are schematically involved.@*METHODS@#In this retrospective study, 38 subjects with functional Class III malocclusion and two lateral cephalograms were selected. The first lateral cephalogram was taken with the mandible in the habitual occlusal position, and the second in anterior edge-to-edge bite. Paired t-test was used to analyze changes in the PAS, hyoid bone, tongue, and soft palate, followed by mandibular posterior displacement. Pearson's correlation analysis was used to determine the relationship between the amount of mandibular posterior displacement and other variables.@*RESULTS@#A statistically significant decrease was observed in the PAS following mandibular posterior displacement. Along with mandibular posterior displacement, the tongue decreased in length (p < 0.001) and increased in height (p < 0.05), while the soft palate increased in length, decreased in thickness, and was posteriorly displaced (p < 0.001). The hyoid bone was also posteriorly displaced (p < 0.05). There was no correlation between the amount of mandibular posterior displacement and the measured variables.@*CONCLUSIONS@#The PAS showed a statistically significant decrease following mandibular posterior displacement, which was a consequence of retraction of the surrounding structures. However, there were individual variances between the amount of mandibular posterior displacement and the measured variables.

Temporary replacement of congenital missing incisors on mandible using temporary anchorage devices in growing patient: 2-year follow-up

Agenesis of permanent tooth in adolescent patients can be treated either by orthodontic treatment for space closure or by main-taining the space until implant restoration can be carried out in adult. However, gradual atrophy of alveolar bone width makes it dif-ficult to restore the prosthesis in the future or may cause unaesthetic results. Therefore, maintaining of not only the missing space but also the alveolar bone width should be considered. This case is a treatment whereby a temporary replacement of missing 2mandibular incisors in adolescent patient was carried out using 2 temporary anchorage devices (TADs). Two TADs were placed hori-zontally 2 - 3 mm below the top of alveolar ridge, and fixed with artificial teeth by stainless steel wires extended. During the 2 year follow-up, neither gingival inflammation nor loss of the TADs have occurred. In the radiographic evaluation, the growth of the adja-cent alveolar bone was not inhibited, and the width of the alveolar bone was maintained.

Intrusion of the extruded maxillary central incisor using skeletal anchorage system and unilateral segmental intrusion arch

Patients who have a moderate periodontitis with pathologic tooth migration of maxillary incisors, it is necessary not only periodontal treatment for reduce periodontal inflammation, but also orthodontic treatment to teeth repositioning. For orthodontic treatment, it is necessary to apply less force and careful considerations of the center of resistance of the tooth and optimal force of tooth movement. At this time, the segmental arch applied only to the target teeth, is more effective and predictable, because applied force and direction can be controlled. In addition, to design the orthodontic appliance that can prevent the unwanted tooth movement that used as an anchorage is important. In recent years, various types of skeletal anchorage system have been used for preventing loss of the anchorage. We reported the patient who had extruded maxillary central incisor due to pathologic tooth migration, treated by a successful periodontal-orthodontic multidisciplinary treatment using an orthodontic appliance designed to apply less traumatic force and reduce an anchorage loss.

Evaluation of oral health-related quality of life in orthodontic patients using the modified Oral Impact on Daily Performance (OIDP) questionnaire / 대한구강보건학회지

OBJECTIVES: This study evaluated oral health-related quality of life (OHQoL) before and after orthodontic treatment (orthodontic-tx) using the modified Oral Impact on Daily Performance (OIDP) questionnaire. METHODS: Ninety-six subjects (32 males, 64 females; 48 ranging between 12–17 years, 48 ranging between 18–29 years) who completed orthodontic-tx in two dental clinics in Busan from May to December 2013 participated in this study. The participants self-reported their OHQoL on the Korean translated version of the OIDP before and during orthodontic-tx when the brackets were removed from their teeth. The OHQoL was again measured 1 month later. The visual analogue scale (VAS) from 0 (never) to 10 (definitely yes) was used to quantify the OHQoL. The physical, psychological, and social effects of the orthodontic-tx on daily performance were analyzed according to age and gender. RESULTS: The OHQoL score was lower during the orthodontic-tx (7.49±0.19) than before (5.51±0.18), but the final OHQoL score, after orthodontic-tx (9.39±0.07), was higher than the score before treatment. The trend was the same over all sub performances. Before orthodontic-tx, the OHQoL score related to psychological performance (6.98±0.22) was the lowest compared to physical and social performance. During orthodontic-tx, the scores related to physical performance, especially in the older (0.7 times) and female (0.62 times) groups, decreased the most compared to before treatment. Psychological performance, especially in the older (1.81 times) and female (1.66 times) groups, increased the most after orthodontic-tx. CONCLUSIONS: This study confirmed that orthodontic-tx affects the OHQoL according to age and gender. Specific approaches, classified by age and gender, are needed to improve the quality of life of orthodontic dental patients.

Correction to: Hard- and soft-tissue profiles of the midface region in patients with skeletal Class III malocclusion using cone-beam computed tomography multiplanar-reconstructed image analysis / 대한치과교정학회지

In the article, the ‘Class’ of skeletal malocclusion was misprinted as ‘class’ in the main text. The publisher would like to apologize for any inconvenience caused.

Hard- and soft-tissue profiles of the midface region in patients with skeletal Class III malocclusion using cone-beam computed tomography multiplanar-reconstructed image analysis / 대한치과교정학회지

OBJECTIVE: This study examined cone-beam computed tomography (CBCT)-derived multiplanar-reconstructed (MPR) cross-sections to clarify the salient characteristics of patients with skeletal class III malocclusion with midface deficiency (MD). METHODS: The horizontal and sagittal plane intersection points were identified for middle-third facial analysis in 40 patients in the MD or normal (N) groups. MPR images acquired parallel to each horizontal plane were used for length and angular measurements. RESULTS: A comparison of the MD and N groups revealed significant differences in the zygoma prominence among female patients. The convex zygomatic area in the N group was larger than that in the MD group, and the inferior part of the midface in the N group was smaller than that in the MD group for both male and female patients. A significant difference was observed in the concave middle maxillary area among male patients. CONCLUSIONS: This study was conducted to demonstrate the difference between MD and normal face through MPR images derived from CBCT. Male patients in the MD group had a more flattened face than did those in the N group. Female patients in the MD group showed a concave-shaped lower section of the zygoma, which tended to have more severe MD. These findings indicate that orthognathic surgery to improve skeletal discrepancy requires different approaches in male and female patients.

Comparison of masticatory efficiency according to Angle's classification of malocclusion / 대한치과교정학회지

OBJECTIVE: The objective of this study was to investigate the differences in masticatory efficiency among patients with different Angle's classes of malocclusion and to assess the correlation between masticatory efficiency and the occlusal contact area. METHODS: The mixing ability index (MAI) was calculated for measuring masticatory efficiency of 61 adult patients according to Angle's classifications of malocclusion. The study included 25, 15, and 21 patients with Angle's Class I, II, and III malocclusions, respectively. Silicone interocclusal recording material was used to measure the occlusal contact area. RESULTS: Both the MAI and occlusal contact area showed the highest average values in the Class I malocclusion group, followed by the Class II and Class III malocclusion groups. No significant difference was observed in the MAI values between the Class I and Class II malocclusion groups (p > 0.05), whereas a significant difference was observed between the Class I and Class III malocclusion groups (p < 0.01) and between the Class II and Class III malocclusion groups (p < 0.05). A weak positive correlation was also observed between the MAI and occlusal contact area (p < 0.01, r² = 0.13). CONCLUSIONS: The results of this study indicated that masticatory efficiency was the highest in patients with Angle's Class I malocclusion, followed by those with Angle's Class II and Angle's Class III malocclusions. Moreover, a weak positive correlation was observed between masticatory efficiency and the occlusal contact area.

Managements of ankylosed incisor occurred during adolescence using alveolar bone distraction osteogenesis and decoronation: case report

One of the common complications of dental injury is tooth ankylosis. Unlike adults, when tooth ankylosis occurs in the adolescents, ankylosis interfered the growth of the adjacent alveolar bone, resulting in the developmental failure of the alveolar bone and subsequent open bite. The most common treatment option for ankylosed tooth is extraction. However, when prognosis of ankylosed tooth after extraction is expected to be poor due to severity of infrapositioning or prosthetic replacement cannot be performed immediately, various treatment options should be considered. This report suggests multidisciplinary treatment that might bring functionally and esthetically favorable result included alveolar bone distraction osteogenesis and decoronation of ankylosed maxillary anterior tooth with orthodontic and prosthetic treatments.

Comparison of postoperative changes in the distal and proximal segments between conventional and sliding mini-plate fixation following mandibular setback / 대한치과교정학회지

OBJECTIVE: The purpose of the present study was to evaluate the postoperative three-dimensional (3D) changes in the proximal segments after mandibular setback sagittal split ramus osteotomy and to compare the changes between the conventional mini-plate fixation and semi-rigid sliding plate fixation. METHODS: Cone-beam computed tomography (CBCT) images were used to evaluate the postoperative 3D changes in the proximal segments during the healing process. CBCT images were superimposed using the symphysis and the lower anterior mandible as references. RESULTS: There were no statistically significant differences between the conventional mini-plate and semi-rigid sliding plate groups (p > 0.05). With respect to the distribution of changes greater than 2 mm in the landmarks, the right condylion, right coronoid process, and left condylion showed ratios of 55.6%, 50.0%, and 44.4%, respectively, in the semi-rigid sliding plate group; however, none of the landmarks showed ratios greater than 30% in the conventional mini-plate group. CONCLUSIONS: There were no statistically significant differences in postoperative changes in the segments between the conventional mini-plate and semi-rigid sliding plate groups. Nevertheless, while selecting the type of fixation technique, clinicians should consider that landmarks with greater than 2 mm changes were higher in the semi-rigid sliding plate group than in the conventional mini-plate group.

Quantitative evaluation of midpalatal suture maturation via fractal analysis / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to determine whether the results of fractal analysis can be used as criteria for midpalatal suture maturation evaluation. METHODS: The study included 131 subjects aged over 18 years of age (range 18.1–53.4 years) who underwent cone-beam computed tomography. Skeletonized images of the midpalatal suture were obtained via image processing software and used to calculate fractal dimensions. Correlations between maturation stage and fractal dimensions were calculated using Spearman's correlation coefficient. Optimal fractal dimension cut-off values were determined using a receiver operating characteristic curve. RESULTS: The distribution of maturation stages of the midpalatal suture according to the cervical vertebrae maturation index was highly variable, and there was a strong negative correlation between maturation stage and fractal dimension (−0.623, p < 0.001). Fractal dimension was a statistically significant indicator of dichotomous results with regard to maturation stage (area under curve = 0.794, p < 0.001). A test in which fractal dimension was used to predict the resulting variable that splits maturation stages into ABC and D or E yielded an optimal fractal dimension cut-off value of 1.0235. CONCLUSIONS: There was a strong negative correlation between fractal dimension and midpalatal suture maturation. Fractal analysis is an objective quantitative method, and therefore we suggest that it may be useful for the evaluation of midpalatal suture maturation.

Orthognathic surgery on Skeletal Class III patiens with collapsed vertical dimension: case report

Patients who lost posterior teeth due to periodontitis or dental caries have collapsed vertical dimension, unstable occlusion and change of the mandibular position. In particular, patients in orthognathic surgery, clinician should re-establish the pre-operative stable position of mandibular condyle in articular fossa and favorable vertical dimension for high post-operative stability of mandible. Therefore, interdisciplinary approach and co-operation, including prosthetics, orthodontics, oral and maxillofacial surgeon, from diagnosis and treatment plan is important to get a good outcome. This case report was patients who had collapsed occlusal plane due to severe dental caries on maxillary molars with skeletal Class III malocclusion. Before orthognathic surgery, resetting of maxillary occlusal plane with temporary removable denture was performed. Then successful multidisciplinary approach was done and lead to acceptable clinical outcome.

Correlation between skeletal and dental changes after mandibular setback surgery-first orthodontic treatment: Cone-beam computed tomography-generated half-cephalograms / 대한치과교정학회지

OBJECTIVE: To investigate skeletal and dental changes after application of a mandibular setback surgery-first orthodontic treatment approach in cases of skeletal Class III malocclusion. METHODS: A retrospective study of 34 patients (23 men, 11 women; mean age, 26.2 +/- 6.6 years) with skeletal Class III deformities, who underwent surgery-first orthodontic treatment, was conducted. Skeletal landmarks in the maxilla and mandible at three time points, pre-treatment (T0), immediate-postoperative (T1), and post-treatment (T2), were analyzed using cone-beam computed tomography (CBCT)-generated half-cephalograms. RESULTS: The significant T0 to T1 mandibular changes occurred -9.24 +/- 3.97 mm horizontally. From T1 to T2, the mandible tended to move forward 1.22 +/- 2.02 mm, while the condylar position (Cd to Po-perpendicular plane) shifted backward, and the coronoid process (Cp to FH plane) moved vertically. Between T1 and T2, the vertical dimension changed significantly (p < 0.05). Changes in the vertical dimension were significantly correlated to T1 to T2 changes in the Cd to Po-perpendicular plane (r = -0.671, p = 0.034), and in the Cp to FH plane (r = 0.733, p = 0.016), as well as to T0 to T1 changes in the Cp to Po-perpendicular plane (r = 0.758, p = 0.011). CONCLUSIONS: Greater alterations in the vertical dimension caused larger post-treatment (T2) stage skeletal changes. Studying the mandibular position in relation to the post-surgical vertical dimension emphasized the integral importance of vertical dimension control and proximal segment management to the success of surgery-first orthodontic treatment.

Correlation between skeletal and dental changes after mandibular setback surgery-first orthodontic treatment: Cone-beam computed tomography-generated half-cephalograms / 대한치과교정학회지

OBJECTIVE: To investigate skeletal and dental changes after application of a mandibular setback surgery-first orthodontic treatment approach in cases of skeletal Class III malocclusion. METHODS: A retrospective study of 34 patients (23 men, 11 women; mean age, 26.2 +/- 6.6 years) with skeletal Class III deformities, who underwent surgery-first orthodontic treatment, was conducted. Skeletal landmarks in the maxilla and mandible at three time points, pre-treatment (T0), immediate-postoperative (T1), and post-treatment (T2), were analyzed using cone-beam computed tomography (CBCT)-generated half-cephalograms. RESULTS: The significant T0 to T1 mandibular changes occurred -9.24 +/- 3.97 mm horizontally. From T1 to T2, the mandible tended to move forward 1.22 +/- 2.02 mm, while the condylar position (Cd to Po-perpendicular plane) shifted backward, and the coronoid process (Cp to FH plane) moved vertically. Between T1 and T2, the vertical dimension changed significantly (p < 0.05). Changes in the vertical dimension were significantly correlated to T1 to T2 changes in the Cd to Po-perpendicular plane (r = -0.671, p = 0.034), and in the Cp to FH plane (r = 0.733, p = 0.016), as well as to T0 to T1 changes in the Cp to Po-perpendicular plane (r = 0.758, p = 0.011). CONCLUSIONS: Greater alterations in the vertical dimension caused larger post-treatment (T2) stage skeletal changes. Studying the mandibular position in relation to the post-surgical vertical dimension emphasized the integral importance of vertical dimension control and proximal segment management to the success of surgery-first orthodontic treatment.

Miniscrews versus surgical archwires for intermaxillary fixation in adults after orthognathic surgery / 대한치과교정학회지

OBJECTIVE: We compared the skeletal and dental changes that resulted from the use of two methods of intermaxillary fixation (IMF)-miniscrews and surgical archwire-in 74 adult patients who had Class III malocclusion and were treated with the same orthognathic surgical procedure at a hospital in Korea. METHODS: All the patients underwent Le Fort I osteotomy and bilateral sagittal split ramus osteotomy with rigid fixation. They were divided into two groups according to the type of IMF used-group 1 underwent surgical archwire fixation and group 2 underwent orthodontic miniscrew fixation. In a series of cephalograms for each patient, we compared vertical and horizontal tooth-position measurements: (a) immediately after surgery (T0), (b) 3 months after surgery (T1), and (c) 6 months after surgery (T2). Cephalometric changes within each group were examined using one-way analysis of variance (ANOVA) while the independent samples t-test procedure was used to compare the two groups. RESULTS: After surgery, the maxillary incisors tended to be proclined in both groups although there were no significant differences. Incisor overbite increased significantly in both groups from T0 to T1, and the miniscrew group (group 2) showed slightly greater overbite than the archwire group (group 1). CONCLUSIONS: This study suggest that the use of orthodontic miniscrews and orthodontic surgical archwire for IMF in adult patients results in similar skeletal and dental changes.

Cone-beam computed tomographic evaluation of the condylar remodeling occurring after mandibular set-back by bilateral sagittal split ramus osteotomy and rigid fixation / 대한치과교정학회지

OBJECTIVE: To evaluate condylar head remodeling after mandibular set-back sagittal split ramus osteotomy (SSRO) with rigid fixation in skeletal class III deformities. The correlation between condylar head remodeling and condylar axis changes was determined using cone-beam computed tomography (CBCT) superimposition. METHODS: The CBCT data of 22 subjects (9 men and 13 women) who had undergone mandibular set-back SSRO with rigid fixation were analyzed. Changes in the condylar head measurements and the distribution of the signs of condylar head remodeling were evaluated by CBCT superimposition. RESULTS: The subjects showed inward rotation of the axial condylar angle; reduced condylar heights on the sagittal and coronal planes; and resorptive remodeling in the anterior and superior areas on the sagittal plane, superior and lateral areas on the coronal plane, and anterior-middle and anterior-lateral areas on the axial plane (p < 0.05). CONCLUSIONS: The CBCT superimposition method showed condylar head remodeling after mandibular set-back SSRO with rigid fixation. In skeletal class III patients, SSRO with rigid fixation resulted in rotation, diminution, and remodeling of the condylar head. However, these changes did not produce clinical signs or symptoms of temporomandibular disorders.

Relationship between chin deviation and the position and morphology of the mandible in individuals with a unilateral cleft lip and palate / 대한치과교정학회지

OBJECTIVE: In this study, we aimed to examine the relationship between chin deviation and the positional and morphological features of the mandible and to determine the factors that contributed to chin deviation in individuals with a unilateral cleft lip and palate (UCLP). METHODS: Cone-beam computed tomography (CBCT) images of 28 adults with UCLP were analyzed in this study. Segmented three-dimensional temporomandibular fossa and mandible images were reconstructed, and angular, linear, and volumetric parameters were measured. RESULTS: For all 28 individuals, the chin was found to deviate to the cleft side by 1.59 mm. Moreover, among these 28 individuals, only 7 showed distinct (more than 4 mm) chin deviation, which was toward the cleft side. Compared to the non-cleft side, the mandibular body length, frontal ramal inclination, and vertical position of the condyle were lower and inclination of the temporomandibular fossa was steeper on the cleft side. Furthermore, the differences in inclination of the temporomandibular fossa, mandibular body length, ramus length, and condylar volume ratio (non-deviated/deviated) were positively correlated with chin deviation. CONCLUSIONS: UCLP individuals show mild chin deviation to the cleft side. Statistical differences were noted in the parameters that represented positional and morphological asymmetries of the mandible and temporomandibular fossa; however, these differences were too small to indicate clinical significance.