Correction to: The structural changes of pharyngeal airway contributing to snoring after orthognathic surgery in skeletal class III patients / 대한악안면성형재건외과학회지

The publication of this article unfortunately contained several mistakes.

Evaluation of the Midpalatal Suture Maturation in Young Koreans Using Cone-Beam Computed Tomography

PURPOSE: The aim of this study was to evaluate the ossification and maturation of the midpalatal suture in young Koreans using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: The study sample consisted of 40 patients with ages from 8.2 to 23.6 years who visited the Department of Orthodontics, Chung-Ang University Dental Hospital. CBCT images were taken for diagnosis. From the CBCT image, morphological stages and Hounsfield units (HU) of midpalatal suture were obtained to evaluate the midpalatal suture maturation. Spearman's correlation coefficients were calculated to analyze relationships between chronological age, morphological stage, and HU. RESULT: There was a wide variation in the morphology of the midpalatal suture in each age group. It showed a modest relationship between the chronological age and the degree of morphological stages. Also there was a modest relationship between the chronological age and HU. In contrast, there was a significant relationship between morphological stages and HU of midpalatal suture (P < 0.01). CONCLUSION: CBCT images can be used for the evaluation of midpalatal suture maturation. For the estimation of the prognosis of rapid maxillary expansion, CBCT may be reliable for the assessment of the maturation of the midpalatal suture.

The structural changes of pharyngeal airway contributing to snoring after orthognathic surgery in skeletal class III patients / 대한악안면성형재건외과학회지

BACKGROUND: Two-jaw surgery including mandibular and maxillary backward movement procedures are commonly performed to correct class III malocclusion. Bimaxillary surgery can reposition the maxillofacial bone together with soft tissue, such as the soft palate and the tongue base. We analyzed changes of pharyngeal airway narrowing to ascertain clinical correlations with the prevalence of snoring after two-jaw surgery. METHODS: A prospective clinical study was designed including a survey on snoring and three-dimensional (3D) computed tomography (CT) in class III malocclusion subjects before and after bimaxillary surgery. We conducted an analysis on changes of the posterior pharyngeal space find out clinical correlations with the prevalence of snoring. RESULTS: Among 67 subjects, 12 subjects complained about snoring 5 weeks after the surgical correction, and examining the 12 subjects after 6 months, 6 patients complained about the snoring. The current findings demonstrated the attenuation of the largest transverse width (LTW), anteroposterior length (APL), and cross-sectional area (CSA) following bimaxillary surgery given to class III malocclusion patients, particularly at the retropalatal level. The average distance of maxillary posterior movements were measured to be relatively higher (horizontal distance 3.9 mm, vertical distance 2.6 mm) in case of new snorers. CONCLUSIONS: This study found that bimaxillary surgery could lead to the narrowing of upper airway at the retropalatal or retroglossal level as well as triggering snoring in subjects with class III malocclusion. Based on the current clinical findings, we also found that upper airway narrowing at retropalatal level may contribute to increasing the probability of snoring and that polysonography may need to be performed before orthognathic surgery in subjects with class III malocclusion.

Complications after dental implant surgery with iliac bone graft; Case report

Evaluation of clinical methods in the diagnosis of temporomandibular joint disorders: a comparison study with magnetic resonance imaging

PURPOSE: The diagnostic relevancies and characteristics and of clinical methods in the diagnosis of internal derangement (ID) were tested by comparing the results of them with those of magnetic resonance imaging (MRI). METHODS: 75 patients (150 temporomandibular joints; TMJs), who were suspected to have ID by clinical diagnoses, were included. Clinical diagnoses including mouth opening pathway and TMJ sound were conducted and MRI takings were done. Accuracies, sensitivities, specificities, positive predictive values, and negative predictive values of clinical diagnosis, mouth opening pathway, and TMJ sound were calculated by comparing with diagnoses with MRIs. RESULTS: Accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of clinical diagnosis were 59.3%, 83%, 49%, 81%, and 51%. They were 59%, 82%, 25%, 73%, and 35% for mouth opening pathways. Although deviation was somewhat accurate for representing disc displacement with reduction (ADDWR), other discrepancies on opening pathways were not clinically relevant. Accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of clicking sounds were 85%, 49%, 78%, 85%, and 37%. TMJs with crepitus were only three. But all TMJs with crepitus were diagnosed to have disc displacement without reduction (ADDWOR). CONCLUSION: When compared with diagnoses with MRIs, clinical diagnoses for ID were not so accurate. But they were suitable for screening tests for ID. Opening pathways and TMJ sounds were not so relevant in the diagnoses of IDs and so it was concluded that considerations for other factors must be included in the diagnoses of IDs.

Effective reduction of mandibular angle fracture with mini-implant; case report

In an open reduction of the mandibular angle fracture, it is crucial to approximate each fracture segment as closer as possible for the reduction of the healing period. In this case report, we proposed a new technique for the mandibular angle fracture. This was designed to minimize the gap between two separated segments using mini-implants and surgical wires. Mini-implants were placed around the fracture line, followed by wire ligation to minimize the fracture gap. And then internal fixation was easily employed with plates and screws. The advantages of this technique were reduced time for operation, the promotion of healing, rapid functional recovery, and few complications.

Post operative evaluation for retromandibular approach of subcondylar fractures

PURPOSE: The classic technique for open reduction of subcondylar fractures is the submandibular approach. The aim of this study was to evaluate clinical result of retromandibular approach to displaced subcondylar fractures. MATERIAL AND METHODS: During a period of 24months we perfomed a prospective study with a retromandibular approach in 23 paients with displaced subcondylar fractures. In this article we describe clinical result in 23 patients with follow ups for 3 months after surgery. Preoperatively all patients had malocclusion and radiology demonstrated displacement. RESULT: The retromandibularl approach for ORIF was good in all case. Mouth opening(M/O) was 49mm. Occlusion was good too. Permanent facial nerve palsy was not detected. CONCLUSION: Our findings indicate that the retromandibular approach is a safe technique for subcondylar fractures.

The long-term stability of the lower incisor axis in Class II division 2 malocclusions / 대한치과교정학회지

The purpose of this study was to evaluate the post-retention stability of the lower incisor axis in Class II division 2 malocclusions. The dental casts and lateral cephalograms from before (T1) and after (T2) orthodontic treatment and long-term post-retention (T3) in 62 Class II division 2 malocclusion cases were included in this study. After several linear and angular measurements at each time were taken, the significance in the amount of change of the lower incisor axis for each gender and extraction versus non-extraction was evaluated. The results showed that the lower incisors that inclined labially during treatment were unstable and relapsed to the original lingual position in Class II division 2 malocclusions (p 0.05). There was no significant difference between male and female groups for the axial change of the lower incisors (p > 0.05). As a result of multiple regression analysis, the cephalometric measurement best predicting the lower incisor position to the A-Pog line post-retention was pre-treatment L1-Apog(mm) and pre-treatment SNGoMe(degrees ). Because of the instability of labially inclined lower incisors after orthodontic treatment, the treatment goal should be the pre-treatment incisor axial position.

The effect of bracket width on frictional force between bracket and arch wire during sliding tooth movement / 대한치과교정학회지

Frictional force between the orthodontic bracket and arch wire during sliding tooth movement is related to many factors, such as the size, shape and material of both the bracket and wire, ligation method and the angle formed between the bracket and wire. There have been clear conclusions drawn in regard to most of these factors, but as to the effect of bracket width on frictional force there are only conflicting studies. This study was designed to investigate the effect of bracket width on the amount of frictional forces generated during clinically simulated tooth movement. Three different widths of brackets (0.018x0.025"standard), narrow (2.40mm), medium (3.00mm) and wide (4.25mm) were used in tandem with 0.016x0.022" stainless steel wire. Three bracket-arch wire combinations were drawn on for 4 minutes on a testing apparatus with a head speed of 0.5mm/min and tested 7 times each. To reproduce biological conditions, dentoalveolar models were designed with indirect technique using a material with similar elastic properties as periodontal ligament (PDL). In addition, to minimize the effect of ligation force, elastomer was used with added resin, which was attached to the bracket to make up for the discrepancies of bracket width. The results were as follows: 1. Maximum frictional force for each bracket-arch wire combination was: Narrow (2.40mm) : 68.09+/-4.69 gmf Medium (3.00mm) : 72.75+/-4.98 gmf Wide (4.25mm) : 72.59+/-4.54 gmf 2. Frictional force was increased with more displacement of wire through the bracket slot. 3. The ANOVA post-hoc test showed that the bracket width had no significant effect on frictional force when tested under clinically simulated conditions (P>0.05)

Relationship between maximum bite force and facial skeletal pattern / 대한치과교정학회지

The purpose of this study was to measure maximum bite force and to investigate its relationship with anteroposterior, vertical, and transverse facial skeletal measurements. From among the dental students at the College of Dentistry, forty subjects (26 male and 14 female) were selected. With two sets of strain gauge, maximum bite force at the right and left first molars and anterior teeth was measured in the morning and afternoon. After taking lateral and posteroanterior cephalograms, fifty and nineteen variables were evaluated, respectively. Paired t-tests and an independent t-test were done and correlation coefficients were obtained. 1. The maximum bite force at the first molars was 68.0+/-13.9 kg in males and 55.6+/-10.5 kg in females (p0.05). 3. Significant difference was observed between the strong bite force group and the weak bite force group in some cephalometric and other measurements (p<0.05). N-S-Ar, S-Ar-Go, FH-H1, MPA and MMO showed a significant difference in posterior maximum bite force (P). N-S-Ar and FH-H1 also showed a significant difference in anterior maximum bite force (A). 4. Several cephalometric variables showed some correlation with maximum bite force (p<0.05). N-S-Ar, S-Ar-Go, UGA, FH-H6, FH-H1, body weight and MMO were significantly correlated with posterior maximum bite force (P). Go-Me, P-1 and IMPA were significantly correlated with anterior maximum bite force (A).