Late development of a mandibular second premolar

Bicakci, Ali Altug,Doruk, Cenk,Babacan, Hasan The Korean Association Of Orthodontists 2012 대한치과교정학회지 Vol.42 No.2

In this report, we present the case of a girl with delayed odontogenesis of a lower second premolar for which she was followed up for 8.5 years. Congenital absence of permanent mandibular second premolars was observed at the initial radiographic examination at 8 years and 1 month. One year later, during the treatment period, an unexpected odontogenesis of a right second premolar was diagnosed on follow-up radiography. The original treatment plan was revised and a new plan was successfully implemented. This unusual case showed that the orthodontist's clinical philosophy must be flexible because unexpected situations can arise, especially when treating growing patients.

Age, extraction rate and jaw surgery rate in Korean orthodontic clinics and small dental hospitals

Jung, Min-Ho The Korean Association Of Orthodontists 2012 대한치과교정학회지 Vol.42 No.2

Objective: This study aimed to investigate the current data regarding age, sex, and Angle Classification of Korean orthodontic patients and influence of these factors on the tendency to undergo extraction and orthognathic surgery. Methods: The recent trends of Korean orthodontic patients were assessed using questionnaire survey. The questionnaires were e-mailed to orthodontists who met the study criteria; 58% of the orthodontists opened the e-mails, and 27.7% replied to the e-mails. In all, the medical records of 11,340 patients who underwent orthodontic treatment at private clinics and small dental hospitals in Korea were analyzed. Results: The percentage of female patients in the study sample was 69.6%, and the average age of the patients was 19.87 years. The percentage of patients who were older than 19 years was 50.2%. Class II and Class III malocclusions were noted in 33.6% and 23.6% of patients, respectively. Extraction and orthognathic surgery were performed in 60.4% and 6.9% of patients, respectively. Conclusions: The results showed that there were a high percentage of adult, Class II malocclusion and extraction patients in private practices and small dental hospitals during the study period. Further, a relatively high proportion of adult patients opted to undergo orthognathic surgery.

Soft-tissue thickness of South Korean adults with normal facial profiles

Cha, Kyung-Suk The Korean Association Of Orthodontists 2013 대한치과교정학회지 Vol.43 No.4

Objective: To standardize the facial soft-tissue characteristics of South Korean adults according to gender by measuring the soft-tissue thickness of young men and women with normal facial profiles by using three-dimensional (3D) reconstructed models. Methods: Computed tomographic images of 22 men aged 20 - 27 years and 18 women aged 20 - 26 years with normal facial profiles were obtained. The hard and soft tissues were three-dimensionally reconstructed by using Mimics software. The soft-tissue thickness was measured from the underlying bony surface at bilateral (frontal eminence, supraorbital, suborbital, inferior malar, lateral orbit, zygomatic arch, supraglenoid, gonion, supraM2, occlusal line, and subM2) and midline (supraglabella, glabella, nasion, rhinion, mid-philtrum, supradentale, infradentale, supramentale, mental eminence, and menton) landmarks. Results: The men showed significantly thicker soft tissue at the supraglabella, nasion, rhinion, mid-philtrum, supradentale, and supraglenoid points. In the women, the soft tissue was significantly thicker at the lateral orbit, inferior malar, and gonion points. Conclusions: The soft-tissue thickness in different facial areas varies according to gender. Orthodontists should use a different therapeutic approach for each gender.

The relationship between malocclusion and menarcheal age, and its secular trend for Korean women

Choi, Yoon-Jeong,Chung, Choo-Ryung,Kim, Kyung-Ho The Korean Association Of Orthodontists 2012 대한치과교정학회지 Vol.42 No.1

Objective: This study aimed to evaluate the mean age of menarche, its secular trend in Korean women, and the relationship between malocclusion and the rate of skeletal maturation, as defined by menarcheal age. Methods: We retrospectively collected data on menarcheal age from 931 Korean women born during 1961 - 1997. Subjects were divided by the malocclusion type and birth-year decade into 3 and 4 groups, respectively. The mean menarcheal age for each group was determined, and one-way ANOVA was performed for intergroup comparison (p = 0.05). Two-way ANOVA was also performed to compare all the 12 subgroups (p = 0.05). Results: The mean age of menarche was 12.82 years for Korean women born during 1961 - 1997. A distinct downward secular trend of menarcheal age was noticed (p < 0.05). For the birth-year decade 1961 - 1970, the Class III malocclusion group showed earlier onset of menarche than the other malocclusion groups (p < 0.05), but the other birth-year groups did not show any significant difference in the type of malocclusion (p > 0.05). Conclusions: A positive secular trend towards earlier menarche exists among Korean women. Malocclusion does not show any significant relationship with the rate of skeletal maturation, as defined by menarcheal age.

Associations between normative and self-perceived orthodontic treatment needs in young-adult dental patients

Oshagh, Morteza,Salehi, Parisa,Pakshir, Hamidreza,Bazyar, Leyla,Rakhshan, Vahid The Korean Association Of Orthodontists 2011 대한치과교정학회지 Vol.41 No.6

Objective: Our aim was to determine the correlation between dental treatment need as assessed by the components of the index of orthodontic treatment need (IOTN) and a self-evaluation questionnaire in a population selected from the dental clinics of Shiraz, Iran. Methods: The dental treatment needs of 240 participants (120 men and 120 women) were measured on the basis of the IOTN dental health component (IOTN-DHC), IOTN aesthetic component (IOTN-AC), IOTN AC determined by the examiner (IOTN-ACE), and a self-evaluation questionnaire (SEQ). The correlations between the treatment needs assessed by all the methods as well as the correlations of the treatment needs with age and gender were assessed using a Spearman's correlation coefficient (${\alpha}$ = 0.01). Results: All methods were significantly correlated ($p{\leq}0.001$). The associations of IOTN-ACE with IOTN-DHC and SEQ were moderately significant (rho = 0.49 and 0.41, respectively). The associations of IOTN-AC with IOTN-DHC and SEQ were weakly significant (rho = 0.24 and 0.35, respectively). The IOTN-DHC was moderately associated with SEQ (rho = 0.53). Gender and age were not associated with treatment needs estimated by any of the methods used ($p$ > 0.06). Conclusions: The correlations between the self-evaluation and the IOTN components in young adults were close to those reported in children, and IOTN-ACE was more reliable than IOTN-AC.

Evaluation of alveolar bone loss following rapid maxillary expansion using cone-beam computed tomography

Baysal, Asli,Uysal, Tancan,Veli, Ilknur,Ozer, Torun,Karadede, Irfan,Hekimoglu, Seyit The Korean Association Of Orthodontists 2013 대한치과교정학회지 Vol.43 No.2

Objective: To evaluate the changes in cortical bone thickness, alveolar bone height, and the incidence of dehiscence and fenestration in the surrounding alveolar bone of posterior teeth after rapid maxillary expansion (RME) treatment using cone-beam computed tomography (CBCT). Methods: The CBCT records of 20 subjects (9 boys, mean age: $13.97{\pm}1.17$ years; 11 girls, mean age: $13.53{\pm}2.12$ year) that underwent RME were selected from the archives. CBCT scans had been taken before (T1) and after (T2) the RME. Moreover, 10 of the subjects had 6-month retention (T3) records. We used the CBCT data to evaluate the buccal and palatal aspects of the canines, first and second premolars, and the first molars at 3 vertical levels. The cortical bone thickness and alveolar bone height at T1 and T2 were evaluated with the paired-samples t-test or the Wilcoxon signed-rank test. Repeated measure ANOVA or the Friedman test was used to evaluate the statistical significance at T1, T2, and T3. Statistical significance was set at p < 0.05. Results: The buccal cortical bone thickness decreased gradually from baseline to the end of the retention period. After expansion, the buccal alveolar bone height was reduced significantly; however, this change was not statistically significant after the 6-month retention period. During the course of the treatment, the incidence of dehiscence and fenestration increased and decreased, respectively. Conclusions: RME may have detrimental effects on the supporting alveolar bone, since the thickness and height of the buccal alveolar bone decreased during the retention period.

Three-dimensional evaluation of midfacial asymmetry in patients with nonsyndromic unilateral cleft lip and palate by cone-beam computed tomography

Choi, Youn-Kyung,Park, Soo-Byung,Kim, Yong-Il,Son, Woo-Sung The Korean Association Of Orthodontists 2013 대한치과교정학회지 Vol.43 No.3

Objective: To compare three-dimensionally the midfacial hard- and soft-tissue asymmetries between the affected and the unaffected sides and determine the relationship between the hard tissue and the overlying soft tissue in patients with nonsyndromic complete unilateral cleft lip and palate (UCLP) by cone-beam computed tomography (CBCT) analysis. Methods: The maxillofacial regions of 26 adults (18 men, 8 women) with nonsyndromic UCLP were scanned by CBCT and reconstructed by three-dimensional dental imaging. The frontal-view midfacial analysis was based on a $3{\times}3$ grid of vertical and horizontal lines and their intersecting points. Two additional points were used for assessing the dentoalveolar area. Linear and surface measurements from three reference planes (Basion-perpendicular, midsagittal reference, and Frankfurt horizontal planes) to the intersecting points were used to evaluate the anteroposterior, transverse, and vertical asymmetries as well as convexity or concavity. Results: Anteroposteriorly, the soft tissue in the nasolabial and dentoalveolar regions was significantly thicker and positioned more anteriorly on the affected side than on the unaffected side (p < 0.05). The hard tissue in the dentoalveolar region was significantly retruded on the affected side compared with the unaffected side (p < 0.05). The other midfacial regions showed no significant differences. Conclusions: With the exception of the nasolabial and dentoalveolar regions, no distinctive midfacial hard- and soft-tissue asymmetries exist between the affected and the unaffected sides in patients with nonsyndromic UCLP.

Effects of contamination by either blood or a hemostatic agent on the shear bond strength of orthodontic buttons

Gungor, Ahmet Yalcin,Alkis, Huseyin,Turkkahraman, Hakan The Korean Association Of Orthodontists 2013 대한치과교정학회지 Vol.43 No.2

Objective: To evaluate the effects of contamination by either blood or a hemostatic agent on the shear bond strength (SBS) of orthodontic buttons. Methods: We used 45 freshly extracted, non-carious, impacted third molars that were divided into 3 groups of 15. Each tooth was etched with 37% phosphoric acid gel for 30 s. Human blood or the blood stopper agent was applied to the tooth surface in groups I and II, respectively. Group III teeth were untreated (controls). Orthodontic buttons were bonded to the teeth using light-curing composite resin. After bonding, the SBS of the button was determined using a Universal testing machine. Any adhesive remaining after debonding was assessed and scored according to the modified adhesive remnant index (ARI). ANOVA with post-hoc Tukey's test was used to determine significant differences in SBS and Fisher's exact test, to determine significant differences in ARI scores among groups. Results: ANOVA indicated a significant difference between groups (p < 0.001). The highest SBS values were measured in group III ($10.73{\pm}0.96$ MPa). The SBS values for teeth in groups I and II were significantly lower than that of group III (p < 0.001). The lowest SBS values were observed in group I teeth ($4.17{\pm}1.11$ MPa) (p < 0.001). Conclusions: Contamination of tooth surfaces with either blood or hemostatic agent significantly decreased the SBS of orthodontic buttons. When the contamination risk is high, it is recommended to use the blood stopper agent when bonding orthodontic buttons on impacted teeth.

Biologic stability of plasma ion-implanted miniscrews

Cho, Young-Chae,Cha, Jung-Yul,Hwang, Chung-Ju,Park, Young-Chel,Jung, Han-Sung,Yu, Hyung-Seog The Korean Association Of Orthodontists 2013 대한치과교정학회지 Vol.43 No.3

Objective: To gain basic information regarding the biologic stability of plasma ion-implanted miniscrews and their potential clinical applications. Methods: Sixteen plasma ion-implanted and 16 sandblasted and acid-etched (SLA) miniscrews were bilaterally inserted in the mandibles of 4 beagles (2 miniscrews of each type per quadrant). Then, 250 - 300 gm of force from Ni-Ti coil springs was applied for 2 different periods: 12 weeks on one side and 3 weeks contralaterally. Thereafter, the animals were sacrificed and mandibular specimens including the miniscrews were collected. The insertion torque and mobility were compared between the groups. The bone-implant contact and bone volume ratio were calculated within 800 mm of the miniscrews and compared between the loading periods. The number of osteoblasts was also quantified. The measurements were expressed as percentages and analyzed by independent t-tests (p < 0.05). Results: No significant differences in any of the analyzed parameters were noted between the groups. Conclusions: The preliminary findings indicate that plasma ion-implanted miniscrews have similar biologic characteristics to SLA miniscrews in terms of insertion torque, mobility, bone-implant contact rate, and bone volume rate.

Alveolar bone thickness and lower incisor position in skeletal Class I and Class II malocclusions assessed with cone-beam computed tomography

Baysal, Asli,Ucar, Faruk Izzet,Buyuk, Suleyman Kutalmis,Ozer, Torun,Uysal, Tancan The Korean Association Of Orthodontists 2013 대한치과교정학회지 Vol.43 No.3

Objective: To evaluate lower incisor position and bony support between patients with Class II average- and high-angle malocclusions and compare with the patients presenting Class I malocclusions. Methods: CBCT records of 79 patients were divided into 2 groups according to sagittal jaw relationships: Class I and II. Each group was further divided into average- and high-angle subgroups. Six angular and 6 linear measurements were performed. Independent samples t-test, Kruskal-Wallis, and Dunn post-hoc tests were performed for statistical comparisons. Results: Labial alveolar bone thickness was significantly higher in Class I group compared to Class II group (p = 0.003). Lingual alveolar bone angle (p = 0.004), lower incisor protrusion (p = 0.007) and proclination (p = 0.046) were greatest in Class II average-angle patients. Spongious bone was thinner (p = 0.016) and root apex was closer to the labial cortex in high-angle subgroups when compared to the Class II average-angle subgroup (p = 0.004). Conclusions: Mandibular anterior bony support and lower incisor position were different between average- and high-angle Class II patients. Clinicians should be aware that the range of lower incisor movement in high-angle Class II patients is limited compared to average- angle Class II patients.