Managing oral biofilms to avoid enamel demineralization during fixed orthodontic treatment / 대한치과교정학회지

Enamel demineralization represents the most prevalent complication arising from fixed orthodontic treatment. Its main etiology is the development of cariogenic biofilms formed around orthodontic appliances. Ordinarily, oral biofilms exist in a dynamic equilibrium with the host's defense mechanisms. However, the equilibrium can be disrupted by environmental changes, such as the introduction of a fixed orthodontic appliance, resulting in a shift in the biofilm’s microbial composition from non-pathogenic to pathogenic. This alteration leads to an increased prevalence of cariogenic bacteria, notably mutans streptococci, within the biofilm. This article examines the relationships between oral biofilms and orthodontic appliances, with a particular focus on strategies for effectively managing oral biofilms to mitigate enamel demineralization around orthodontic appliances.

Variation in adhesion of Streptococcus mutans and Porphyromonas gingivalis in saliva-derived biofilms on raw materials of orthodontic brackets / 대한치과교정학회지

Objective@#To evaluate differences in the adhesion levels of the most common oral pathogens, Streptococcus mutans and Porphyromonas gingivalis, in human saliva-derived microcosm biofilms with respect to time and raw materials of orthodontic brackets. @*Methods@#The samples were classified into three groups of bracket materials: 1) monocrystalline alumina ceramic (CR), 2) stainless steel metal (SS), and 3) polycarbonate plastic (PL), and a hydroxyapatite (HA) group was used to mimic the enamel surface. Saliva was collected from a healthy donor, and saliva-derived biofilms were grown on each sample. A realtime polymerase chain reaction was performed to quantitatively evaluate differences in the attachment levels of total bacteria, S. mutans and P. gingivalis at days 1 and 4. @*Results@#Adhesion of S. mutans and P. gingivalis to CR and HA was higher than the other bracket materials (SS = PL < CR = HA). Total bacteria demonstrated higher adhesion to HA than to bracket materials, but no significant differences in adhesion were observed among the bracket materials (CR = SS = PL < HA). From days 1 to 4, the adhesion of P. gingivalis decreased, while that of S. mutans and total bacteria increased, regardless of material type.onclusions: The higher adhesion of oral pathogens, such as S. mutans and P.gingivalis to CR suggests that the use of CR brackets possibly facilitates gingival inflammation and enamel decalcification during orthodontic treatment.

Differences in dentoskeletal and soft tissue changes due to rapid maxillary expansion using a tooth-borne expander between adolescents and adults: A retrospective observational study / 대한치과교정학회지

Objective@#The purpose of this study was to compare the differences in dentoskeletal and soft tissue changes following conventional tooth-borne rapid maxillary expansion (RME) between adolescents and adults. @*Methods@#Dentoskeletal and soft tissue variables of 17 adolescents and 17 adults were analyzed on posteroanterior and lateral cephalograms and frontal photographs at pretreatment (T1) and after conventional RME using tooth-borne expanders (T2). Changes in variables within each group between T1 and T2 were analyzed using Wilcoxon signed-rank test. Mann–Whitney U test was used to determine the differences in the pretreatment age, expansion and post-expansion durations, and dentoskeletal and soft tissue changes after RME between the groups. Spearman’s correlation between pretreatment age and transverse dentoskeletal changes in the adolescent group was calculated. @*Results@#Despite similar amounts of expansion at the crown level in both groups, the adult group underwent less skeletal expansion with less intermolar root expansion after RME than the adolescent group. The skeletal vertical dimension increased significantly in both groups without significant intergroup difference. The anteroposterior position of the maxilla was maintained in both groups, while a greater backward displacement of the mandible was evident in the adult group than that in the adolescent group after RME. The soft tissue alar width increased in both groups without a significant intergroup difference. In the adolescent group, pretreatment age was not significantly correlated with transverse dentoskeletal changes. @*Conclusions@#Conventional RME may induce similar soft tissue changes but different dentoskeletal changes between adolescents and adults.

Relationship between rotational disc displacement of the temporomandibular joint and the dentoskeletal morphology / 대한치과교정학회지

Objective@#The purpose of this study was to evaluate the relationship between rotational disk displacement (DD) of the temporomandibular joint (TMJ) and the dentoskeletal morphology. @*Methods@#Women aged > 17 years were included in this study. Each subject had a primary complaint of malocclusion and underwent routine cephalometric examinations. They were divided into five groups according to the findings on sagittal and coronal magnetic resonance images of their TMJs: bilateral normal disk position, bilateral anterior DD with reduction (ADDR), bilateral rotational DD with reduction (RDDR), bilateral anterior DD without reduction (ADDNR), and bilateral rotational DD without reduction (RDDNR). Twenty-three cephalometric variables were analyzed, and the Kruskal–Wallis test was used to evaluate differences in the dentoskeletal morphology among the five groups. @*Results@#Patients with TMJ DD exhibited a hyperdivergent pattern with a retrognathic mandible, unlike those with a normal disk position. These specific skeletal characteristics were more severe in patients exhibiting DD without reduction than in those with reduction, regardless of the presence of rotational DD. Rotational DD significantly influenced horizontal and vertical skeletal patterns only in the stage of DD with reduction, and the mandible exhibited a more backward position and rotation in patients with RDDR than in those with ADDR. However, there were no significant dentoskeletal differences between ADDNR and RDDNR. @*Conclusions@#The results of this study suggest that rotational DD of TMJ plays an important role in the dentoskeletal morphology, particularly in patients showing DD with reduction.

Relationship between rotational disc displacement of the temporomandibular joint and the dentoskeletal morphology / 대한치과교정학회지

Objective@#The purpose of this study was to evaluate the relationship between rotational disk displacement (DD) of the temporomandibular joint (TMJ) and the dentoskeletal morphology. @*Methods@#Women aged > 17 years were included in this study. Each subject had a primary complaint of malocclusion and underwent routine cephalometric examinations. They were divided into five groups according to the findings on sagittal and coronal magnetic resonance images of their TMJs: bilateral normal disk position, bilateral anterior DD with reduction (ADDR), bilateral rotational DD with reduction (RDDR), bilateral anterior DD without reduction (ADDNR), and bilateral rotational DD without reduction (RDDNR). Twenty-three cephalometric variables were analyzed, and the Kruskal–Wallis test was used to evaluate differences in the dentoskeletal morphology among the five groups. @*Results@#Patients with TMJ DD exhibited a hyperdivergent pattern with a retrognathic mandible, unlike those with a normal disk position. These specific skeletal characteristics were more severe in patients exhibiting DD without reduction than in those with reduction, regardless of the presence of rotational DD. Rotational DD significantly influenced horizontal and vertical skeletal patterns only in the stage of DD with reduction, and the mandible exhibited a more backward position and rotation in patients with RDDR than in those with ADDR. However, there were no significant dentoskeletal differences between ADDNR and RDDNR. @*Conclusions@#The results of this study suggest that rotational DD of TMJ plays an important role in the dentoskeletal morphology, particularly in patients showing DD with reduction.

Evaluation of growth changes induced by functional appliances in children with Class II malocclusion: Superimposition of lateral cephalograms on stable structures / 대한치과교정학회지

Objective@#To compare short- and long-term dentoalveolar, skeletal, and rotational changes evaluated by Björk’s structural method of superimposition between children with Class II malocclusion treated by functional appliances and untreated matched controls. @*Methods@#Seventy-nine prepubertal or pubertal children (mean age, 11.57 ± 1.40 years) with Class II malocclusion were included. Thirty-four children were treated using an activator with a high-pull headgear (Z-activator), while 28 were treated using an activator without a headgear (E-activator). Seventeen untreated children were included as controls. Lateral cephalograms were obtained before treatment (T1), after functional appliance treatment (T2), and after retention in the postpubertal phase (T3). Changes from T1 to T2 and T1 to T3 were compared between the treated groups and control group using multiple linear regression analysis. @*Results@#Relative to the findings in the control group at T2, the sagittal jaw relationship (subspinalenasion- pogonion, p < 0.001), maxillary prognathism (sella-nasion-subspinale, p < 0.05), and condylar growth (p < 0.001) exhibited significant improvements in the Z- and E-activator groups, which also showed a significantly increased maxillary incisor retraction (p < 0.001) and decreased overjet (p < 0.001). Only the E-activator group exhibited significant backward rotation of the maxilla at T2 (p < 0.01). The improvements in the sagittal jaw relationship (p < 0.01) and dental relationship (p < 0.001) remained significant at T3. Condylar growth and jaw rotations were not significant at T3. @*Conclusions@#Functional appliance treatment in children with Class II malocclusion can significantly improve the sagittal jaw relationship and dental relationships in the long term.

Antimicrobial Effects of Ursolic Acid against Mutans Streptococci Isolated from Koreans

Ursolic acid is a triterpenoid compound present in many plants. This study examined the antimicrobial activity of ursolic acid against mutans streptococci (MS) isolated from the Korean population. The antimicrobial activity was evaluated by the minimum inhibitory concentration (MIC) and time kill curves of MS. The cytotoxicity of ursolic acid against KB cells was tested using an MTT assay. The MIC90 values of ursolic acid for Streptococcus mutans and Streptococcus sobrinus isolated from the Korean population were 2 microg/ml and 4 microg/ml, respectively. Ursolic acid had a bactericidal effect on S. mutans ATCC 25175T and S. sobrinus ATCC 33478T at > 2 x MIC (4 microg/ml) and 4 x MIC (8 microg/ml), respectively. Ursolic acid had no cytotoxic effect on KB cells at concentrations at which it exerted antimicrobial effects. The results suggest that ursolic acid can be used in the development of oral hygiene products for the prevention of dental caries.

Comparison of bony changes between panoramic radiograph and cone beam computed tomographic images in patients with temporomandibular joint disorders / 대한치과교정학회지

OBJECTIVE: This study was designed to assess the diagnostic validity of digital panoramic radiographs compared to cone beam computed tomography (CBCT) in patients with temporomandibular joint disorders. METHODS: Panoramic radiograph and CBCT were taken from a total of 212 joints from 106 subjects. The joints were examined by two dentists and divided into the following six groups: normal, flattening, osteophyte formation, erosion, sclerosis, and unclassified. The sensitivity and specificity of each observer and inter-observer reliability were statistically analyzed. RESULTS: The results showed relatively high intra-observer reliability in the diagnosis of both panoramic and CBCT images and the weighted Kappa indices of panoramic and CBCT images were 0.714 and 0.727, respectively. The sensitivities of panoramic images of observer A and B to CBCT images was 82.35% and 84.30%, respectively, while the specificity of observer A and B was 58.06% and 61.54%, respectively. However, guided diagnosis from panoramic and CBCT images were statistically different (p < 0.05). CONCLUSIONS: The present study suggests that the panoramic radiograph could be used as a primary diagnostic device to detect bony changes of temporomandibular joints in clinical orthodontics, because panoramic images showed relatively high sensitivity compared to CBCT images. However, CBCT images may be one of the best choices when a more accurate diagnosis is necessary.

Quantitative analysis of mutans streptococci adhesion to various orthodontic bracket materials in vivo / 대한치과교정학회지

OBJECTIVE: To estimate the effects of bracket material type on enamel decalcification during orthodontic treatment, this study analyzed the adhesion level of mutans streptococci (MS) to orthodontic bracket materials in vivo. METHODS: Three different types of orthodontic bracket materials were used: stainless steel, monocrystalline sapphire, and polycrystalline alumina. A balanced complete block design was used to exclude the effect of positional variation of bracket materials in the oral cavity. Three types of plastic individual trays were made and one subject placed the tray in the mouth for 12 hours. Then, the attached bacteria were isolated and incubated on a mitis salivarius media containing bacitracin for 48 hours. Finally, the number of colony forming units of MS was counted. The experiments were independently performed 5 times with each of the 3 trays, resulting in a total of 15 times. Mixed model ANOVA was used to compare the adhesion amount of MS. RESULTS: There was no difference in colony forming units among the bracket materials irrespective of jaw and tooth position. CONCLUSIONS: This study suggested that the result of quantitative analysis of MS adhesion to various orthodontic bracket materials in vivo may differ from that of the condition in vitro.

The validity of transcranial radiography in diagnosis of internal derangement / 대한치과교정학회지

The purpose of this study was to determine whether association exists between temporomandibular joint (TMJ) characteristics in transcranial radiographs and TMJ internal derangement and to evaluate the validity of transcranial radiographs in diagnosis of internal derangement. Transcranial radiographs and magnetic resonance imaging (MRI) of 113 TMJs from 76 subjects were used for this study and all TMJs were classified into 3 groups according to the results of MRI: normal disk position, disk displacement with reduction, and disk displacement without reduction. Transcranial analysis included linear measurement of joint spaces and condylar head angle measurement. To determine any relationship between transcranial measurements according to disk displacement, one-way ANOVA was used. The results showed that condyle-fossa relationship in standard transcranial radiographs had no relationships with disk displacement. And, as disk displacement progressed, condylar angle between head and neck increased significantly. This result can be interpreted that condylar head angle reflects structural hard tissue change according to internal derangement progress. But this is insufficient in the determination of internal derangement. Therefore, although still clinically helpful, the validity of standard transcranial radiographs to diagnose TMJ internal derangement was questioned.

Surface roughness and surface free energy components of various orthodontic adhesives / 대한치과교정학회지

OBJECTIVE: Surface characteristics of dental materials play an important role in bacterial adhesion. The purpose of this study was to investigate surface characteristics of 5 different light-cured orthodontic adhesives (1 fluoride-releasing composite, 3 non-fluoride-releasing composites, and 1 resin-modified glass ionomer). METHODS: Surface roughness was measured using a confocal laser scanning microscope. Contact angle and surface free energy components were analyzed using the sessile drop method. RESULTS: Surface roughness was significantly different between adhesives despite a relatively small variation (less than 0.05 micrometer). Lightbond and Monolok2 were rougher than Enlight and Transbond XT. There were also significant differences in contact angles and surface free energy components between adhesives. In particular, considerable differences in contact angles and surface free energy components were found between resin modified glass ionomer and the composites. Resin modified glass ionomer showed significantly smaller contact angles in 3 different probe liquids and had higher total surface free energy and stronger polarity, with notably stronger basic property than the composites. CONCLUSION: Resin modified glass ionomer may provide a more favourable environment for bacterial adhesion than composite adhesives.

New evaluation chart of stature and weight for Koreans / 대한치과교정학회지

For orthodontic treatment of growing patients and those which involve long treatment times, knowledge of growth and development are essential. Data from the general growth observation chart being used at present does not reflect the growth transition of modern times. This is because these data are out of date. The present study, therefore, aims to introduce the process of producing a growth curve and growth rate curve based on data which represents a more accurate description of the present situation. The data used were from the 5th nationwide survey, SIZE KOREA 2004 study, carried out by the Technology and Standards Policy Division, Department of Technology and Standards Planning, Ministry of Commerce. Processing and rearranging produced data with variations divided into the three quartiles and the 1st, 5th, 95th and 99th percentiles were included to produce a growth observation chart according to sex, height and weight differences. In the same way, a growth rate curve based on the geometric mean value was produced. The resulting growth charts can be used as an index for growth and development, and used for better communication between the orthodontist, patients and parents.

Clinical crown angulation and inclination of normal occlusion in a large Korean sample / 대한치과교정학회지

Angulation and inclination of clinical crown is important for diagnosing, treatment planning and developing convenient orthodontic attachments. The aim of the study was to establish normative data with higher reliability on the angulation and inclination of clinical crown of Koreans with normal occlusion. This study employed the dental casts of 307 (male, 187; female, 120) adult normal occlusion samples. The angulation and inclination of clinical crown were measured by set-up model checker. In order to ensure reliability, intra- and inter-rater error were evaluated 3 times. The resultant data obtained had excellent reliability, however, when compared with the previous data as well as with gender difference, clinically significant interpretation was impossible because the whithin-dataset normal variation was high, which was common pattern of angulation and inclination measuring data of previous research. The result of this biometric study seemed to suggest more substantive design of the multivariate, high-dimensional interpretation methodology of these normal variation is required if more compatible orthodontic appliance could be developed.

Direct detection of cariogenic streptococci in metal brackets in vivo using polymerase chain reaction / 대한치과교정학회지

Streptococcus mutans and Streptococcus sobrinus are major etiological agents in enamel demineralization around orthodontic appliances. This study was designed to examine the prevalence of these streptococci on orthodontic brackets in vivo using polymerase chain reaction. Four incisor brackets in the upper and lower arches were removed and collected from 80 patients at the time of debonding. The genomic DNA of adhered bacteria was extracted and each dextranase gene of S. mutans and S. sobrinus was amplified using the specific oligonucleotide primers. The results showed that the maxillary incisor brackets were colonized by both cariogenic streptococci to a somewhat higher degree than that taken from the mandible. The prevalence of S. mutans was 50.0% on the maxillary incisor brackets and 33.8% on the mandibular incisor brackets, and that of S. sobrinus was 17.5% and 15.0%, respectively. Both species were detected on the maxillary incisor brackets of 7 patients (8.8%) and the mandibular incisor brackets of 5 patients (6.3%). These results suggest that cariogenic streptococci can adhere to the incisor brackets and may be resident species on the incisor brackets.

Effects of chewable tablet containing sodium fluoride and xylitol on the oral hygiene state in the orthodontic patients / 대한치과교정학회지

The aim of this study was to evaluate the effect a chewable tablet containing sodium fluoride and xylitol (DenPo, Hamizzle, Bucheon, Kyungki) on the oral hygiene state in the orthodontic patients. The subjects consisted of 30 adult orthodontic patients, who have worn the fixed orthodontic appliance at least 6 months. They were instructed to use the tablet forth a day. Gingival index (GI), plaque index (PI), and sulcus bleeding index (SBI) of upper and lower anterior and posterior regions were measured before using the tablet (T0), 2 weeks after using the tablet (T1), and 4 weeks after using the tablet (T2). The data were analyzed with Wilcoxon signed ranks tests. The results were as follows ; 1. PI was decreased significantly in the T1 and T2 stage compared with T0 stage in the both anterior and posterior regions (p 0.05). 2. GI and SBI showed similar results compared with PI. In the T1 and T2 stage, there was statistically significant decrease in the GI and SBI (p < 0.05). This study showed that the DenPo tablet could be used as an adjunct to improve oral hygiene in the orthodontic patients. The decrease of the indices may suggest that DenPo tablet could be effective in the plaque removal and prevention of gingival inflammation in the orthodontic patients.

Locus of control of surgical-orthodontic patient / 대한치과교정학회지

Surgical-orthodontic treatment is an increasingly more common dental procedure whose unique psycho-social or psychological feature has not been fairly quantified objectively. Since the treatment of a surgical-orthodontic (or orthodontic) patient is part science and part art, a subjective recognition of a patient about his or her own treatment may be more important than technical success during and after treatment. Therefore, the knowledge of the patient's underlying psychological status could be useful in the prediction of patient's response to surgical-orthodontic (or orthodontic) treatment. The purpose of this study was to investigate and evaluate the psychological difference between conventional orthodontic patient and surgical-orthodontic patient by using locus of control (LOC) examination. Locus of control scale has been proven to be extremely useful in the prediction of a variety of human behaviors. Two types of locus of control data (I-score, Internal locus of control score; E-score, External locus of control score) were obtained for 42 surgical-orthodontic patients and randomly selected 42 conventional orthodontic patients (as a control group) matched for age and gender. No statistically significant difference was observed in the scale of internal and external locus of control between the groups of surgical-orthodontic patients and conventional orthodontic patients. However, in the group of surgical-orthodontic patients, males showed lower E-score (external locus of control score, higher internal locus of control tendency) than females. The results of this study suggested that the psychological background of surgical-orthodontic patients, in contrast with that of cosmetic surgery patients, has a similar disposition with that of orthodontic patients.

Adherence of salivary proteins to various orthodontic brackets / 대한치과교정학회지

The principal aims of this study were to identify the composition of salivary pellicles formed on various orthodontic brackets and to obtain a detailed information about the protein adsorption profiles from whole whole saliva and two major glandular salivas. Four different types of orthodontic brackets were used. All were upper bicuspid brackets with a 022 x 028 slot Roth prescription; stainless steel metal, monocrystalline sapphire, polycrystalline alumina, and plastic brackets. Bracket pellicles were formed by the incubation of orthodontic brackets with whole saliva, submandibular-sublingual saliva, and parotid saliva for 2 hours. The bracket pellicles were extracted and confirmed by employing sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western transfer methods, and immunodetection. The results showed that low-molecular weight salivary mucin, alpha-amylase, secretory IgA (sIgA), acidic proline-rich proteins, and cystatins were attached to all of these brackets regardless of the bracket types. High-molecular weight mucin, which promotes the adhesion of Streptococcus mutans, did not adhere to any orthodontic brackets. Though the same components were detected in all bracket pellicles, however, the gel profiles showed qualitatively and quantitatively different pellicles, according to the origins of saliva and the bracket types. In particular, the binding of sIgA was more prominent in the pellicles from parotid saliva and the binding of cystatins was prominent in the pellicles from the form plastic brackets. This study indicates that numerous salivary proteins adhere to the orthodontic brackets and these salivary proteins adhere selectively according to bracket types and the types of the saliva.

An evaluation of treatment effects of modified teuscher appliance in Class II division 1 malocclusion / 대한치과교정학회지

The purpose of this study was to evaluate treatment effects of the modified Teuscher appliance (MTA) in early Class II division 1 malocclusion. For this purpose, treatment effects of the bionator were compared with those of the MTA. The twenty subjects who were treated excellently with bionator and MTA were selected in each group. In pre- and post-treatment lateral cephalograms, 50 variables were measured, and then the differences between pretreatment and posttreatment data of the bionator and the MTA were statistically evaluated by t-test. The results were as follows : 1. The linear measurements that showed large difference between the bionator group and the MTA group are U1 to FH, U1 to PP, U6 to FH, U6 to PP, Ar-Pog, ramus height, L1 to A-Pog, L1 to facial plane (p0.05). These results suggest that the bionator influence the mandiblar growth and lower dentoalveolar structures more than the MTA, and the MTA influence upper jaw and upper dentoalveolar structures more than the bionator comparatively in early Class II division I malocclusion.

An evaluation on the indications of bionator in Class II division 1 malocclusion / 대한치과교정학회지

The purpose of this study was to evaluate the indications of bionator in Class II division 1 malocclusion. The 48 subjects were classified into good result group(groupl) and poor result group(group2) in reference to posttreatment molar relation, posttreatment overbite and overjet, posttreatment profile, and relapse. Pretreatment lateral cephalograms were calculated and evaluated by t-test and stepwise discrminant analysis. The results were as follows; 1. In jaw bone relationship, ANB, facial convexity angle, AB to facial plane angle were significantly different between two treatment groups. In denture pattern, Ll to facial plane, Ll to A-Pog, FMIA, and Ul to facial plane were significantly different and in soft tissue profile, protuberance of lower lip and upper lip were significantly different between two treatment groups. 2. The results in according to discriminant analysis stated that Ll to facial plane, ANB, FMIA and protuberance of lower lip help prediction of treatment result of bionator. 3. 3 major influential variables were obtained by stepwise discriminant analysis - Ll to facial plane, articular angle and ANB difference. And Fisher discriminant function was made by these three major variables.

An evaluation of treatment effects of bionator in Class II division 1 malocclusion by finite element method / 대한치과교정학회지

The purpose of this study was to evaluate treatment effects of bionator in Class II division 1 malocclusion by FEM(Finite Element Method). The 73 subjects were classified into good result group and poor result group in reference to posttreatment molar relation, posttreatment overbite and overjet, posttreatment profile, and relapse. Pretreatment and posttreatment lateral cephalograms were taken and FEM was performed. The results were as follow; 1. There was no statistical significance in treatment changes between the sexes, and between the treatment result groups. 2. Treatment changes were not significantly different among the age groups. 3. The effect of treatment period groups on skeletal and dentoalveolar changes were analyzed using ANOVA. Body of maxilla, upper incisor, anterior face, ramus, upper anterior face, lower anterior face and treatment effect were correlated with the treatment period, but correlation coefficients were low. 4. The results of present investigation confirm that Class II bionator can assist in the correction of Class II division 1 malocclusion, mainly due to dentoalveolar changes. 5. There is significant difference in skeletal and dentoalveolar pattern between good result group and poor result group. In poor result group, maxilla was relatively downward and backward rotated, mandible was relatively backward rotated, upper incisor was in relatively lingual position, lower incisor was in relatively labial position.