Analysis of surface roughness and surface free energy characteristics of various orthodontic materials.

Introduction: The purpose of this study was to analyze the differences in surface characteristics of various orthodontic materials; this might provide valuable information on bacterial adhesion to orthodontic materials.

Methods: Surface roughness (SR) and surface free energy (SFE) characteristics of 5 orthodontic adhesives (2 composites resins, 2 resin-modified glass ionomer cements, and 1 compomer), 5 bracket materials (2 stainless steel, 1 monocrystalline sapphire, 1 polycrystalline alumina, and 1 plastic) and bovine incisors were investigated by using confocal laser scanning microscopy and the sessile drop method.

Results: There were significant differences in SR and SFE characteristics among orthodontic materials.

Differential diagnosis for inappropriate upper incisal display during posed smile: contribution of soft tissue and underlying hard tissue.

The amount of upper incisor display (UID) during smile and conversation is one of the most decisive components in aesthetic judgment. The purpose of this study was to find which soft tissue and underlying hard tissue factors contributed to the amount of UID during posed smile (PS) and at rest posture (RP). The subjects consisted of 76 young adults (33 men and 43 women; mean [SD] age, 24.

Maximum closing force of mentolabial muscles and type of malocclusion.

Objective: To measure the closing force of the upper and lower lips and to ascertain the relationship between the maximum closing force of the mentolabial muscles and types of malocclusion.

Materials And Methods: Of those who showed the full eruption of a second molar and no permanent tooth loss, 99 subjects were chosen who showed a positive overbite and ANB and no skeletal asymmetry. By using the Y-meter, which can measure the lip force in the vertical direction using a load cell, the closing forces of the upper and lower lips were measured separately.

Cystatins and cathepsin B during orthodontic tooth movement.

Introduction: The lysosomal cysteine protease cathepsin B is known to play an important role in the resolution of organic matrix, a final step in bone resorption. Cystatins function as an inhibitor of cathepsin B. Determining the correlation between cathepsin B and cystatin levels in gingival crevicular fluid at various times might provide a better understanding of both the dynamics and the metabolic stages of orthodontic tooth movement.

Reliability of landmark identification on monitor-displayed lateral cephalometric images.

Introduction: Our objective was to compare the reliability of landmark identification with hard-copied film images vs monitor-displayed images from digital lateral cephalograms.

Methods: We randomly selected 50 orthodontic patients. Identification and digitization of the cephalometric landmarks were performed 3 times at 2-week intervals by 2 observers.

Which hard and soft tissue factors relate with the amount of buccal corridor space during smiling?

Objective: To investigate which hard and soft tissue factors relate with the amount of buccal corridor area (BCA) during posed smiling.

Materials And Methods: The samples consisted of 92 adult patients (19 men and 73 women; 56 four first bicuspids extraction and 36 nonextraction treatment cases; mean age = 23.5 years), who were treated only with a fixed appliance and finished with Angle Class I canine and molar relationships.

Quantitative determination of adhesion patterns of cariogenic streptococci to various orthodontic brackets.

Introduction: Information about the adhesion of cariogenic streptococci to orthodontic brackets can help to determine a means for preventing enamel demineralization. The purpose of this study was to investigate the adhesion levels of 4 cariogenic streptococci strains to various orthodontic brackets with respect to bracket type, bacterial strain, incubation time, and saliva coating.

Methods: Five bracket types (monocrystalline sapphire, polycrystalline alumina, stainless steel, plastic, and titanium) were incubated with unstimulated whole saliva or phosphate-buffered saline solution for 2 hours.

En masse retraction and two-step retraction of maxillary anterior teeth in adult Class I women. A comparison of anchorage loss.

Objective: To compare the amount of anchorage loss of the maxillary posterior teeth and amount of retraction of the maxillary anterior teeth between en masse retraction and two-step retraction of the anterior teeth.

Materials And Methods: The sample consisted of 30 female adult patients with Class I malocclusion and lip protrusion who needed maximum posterior anchorage. The sample was subdivided into group 1 (n = 15, mean age = 21.

Correction of Class II deep overbite and dental and skeletal asymmetry with 2 types of palatal miniscrews.

This case report describes the orthodontic treatment of a 31-year-old woman who had a Class II molar relationship, anterior crowding, deep overbite, maxillary dental midline deviation, vertical maxillary asymmetry, and a hyperdivergent facial pattern. The maxillary right first premolar and the left second premolar were extracted asymmetrically to correct the anterior crowding and the maxillary dental midline deviation. The maxillary molars were intruded with a midpalatal miniscrew, which helped to correct the vertical molar asymmetry and close the mandibular plane.

Differential gene expression of periodontal ligament cells after loading of static compressive force.

Background: Compressive force is an important mechanical stimulus on the periodontal ligament (PDL) and is closely related to therapeutic tooth movement. In this study, early or late response genes related to the compressive stress in PDL cells were evaluated. Particularly, the expression of interleukin (IL)-6, IL-8, and alkaline phosphatase (ALP) was studied.

Quantitative determination of adhesion patterns of cariogenic streptococci to various orthodontic adhesives.

Objective: To investigate the adhesion of various cariogenic streptococci to orthodontic adhesives.

Materials And Methods: Five light-cure orthodontic adhesives (one fluoride-releasing composite, three non-fluoride-releasing composites, and one resin-modified glass ionomer cement) were used. The adhesive type, bacterial strain, incubation time, and saliva coating were studied.

Discrimination of internal derangement of temporomandibular joint by lateral cephalometric analysis.

Introduction: The purposes of this study were to analyze the progress of internal derangement (ID) of the temporomandibular joint (TMJ) and to find critical yardsticks that can be used during lateral cephalometric analysis to identify subjects with potential ID.

Methods: The sample consisted of 134 women whose primary complaints were malocclusions. They were divided into 5 groups based on the results of magnetic resonance imaging of bilateral TMJs: bilateral normal disc position, unilateral disc displacement with reduction (DDR) and contralateral normal disc position, bilateral DDR, unilateral DDR and contralateral disc displacement without reduction (DDNR), and bilateral DDNR.

Transverse implications of maxillary premolar extraction in Class III presurgical orthodontic treatment.

Introduction: Maxillary premolars are often extracted to resolve incisor proclination in presurgical orthodontic treatment for severe skeletal Class III patients. The aim of this article was to compare arch-width changes and orthodontic tooth movements between maxillary premolar extraction and nonextraction modalities, and to provide an additional indication for presurgical maxillary premolar extraction according to the transverse dental arch characteristics of Class III surgical-orthodontic patients.

Methods: Pretreatment and posttreatment dental casts of 55 adult Class III patients (24 nonextraction, 31 extraction) who underwent surgical-orthodontic treatment were collected.

Evaluation of internal derangement of the temporomandibular joint by panoramic radiographs compared with magnetic resonance imaging.

Introduction: Panoramic radiographs are routinely used in orthodontic diagnosis and treatment planning. It would be useful if these radiographs could also provide information about internal derangement (ID) of the temporomandibular joint (TMJ).

Methods: The sample consisted of 168 condyles in 84 women.

Relationship between temporomandibular joint internal derangement and facial asymmetry in women.

Introduction: Internal derangement (ID) of the temporomandibular joint (TMJ) can cause facial asymmetry. The purposes of this study were to analyze the relationship between facial asymmetry and TMJ ID by using posteroanterior cephalometric variables, and to compare the findings with the results of magnetic resonance imaging (MRI).

Methods: The sample consisted of women seeking orthodontic treatment at Seoul National University Dental Hospital who had routine posteroanterior cephalograms and bilateral MRIs of the TMJ.

Classification of the skeletal variation in normal occlusion.

The aims of this study were to classify normal occlusion samples into specific skeletal types and to analyze the dentoalveolar compensation in a normal occlusion in order to provide the clinically applicable differential diagnostic criteria for an individual malocclusion patient. Lateral cephalograms of 294 normal occlusion samples, who were selected from 15,836 adults through a community dental health survey, were measured. Using a principal component analysis, two factors representing the anteroposterior and vertical skeletal relationships were extracted from 18 skeletal variables.

Cephalometric keys to internal derangement of temporomandibular joint in women with Class II malocclusions.

The aim of this study was to find cephalometric keys to provide information on the progression of temporomandibular internal derangement. The sample consisted of 58 women with Class II malocclusions. They were examined with routine lateral cephalograms and magnetic resonance imaging of the temporomandibular joint (TMJ) before orthodontic treatment.

In vitro expression of matrix metalloproteinase-1, tissue inhibitor of metalloproteinase-1 and transforming growth factor-beta1 in human periodontal ligament fibroblasts.

Extracellular matrix remodelling is mediated via matrix metalloproteinases (MMPs) and their regulatory factors such as tissue inhibitors of metalloproteinases (TIMPs) and transforming growth factor-beta (TGF-beta). The regulation of MMPs is thought to be associated with cytoskeletal changes. In this study, cytoskeletal changes in human periodontal ligament fibroblasts (PDFs) were induced using cytochalasin B (CB) which reorganizes actin microfilaments reversibly, and colchicine which disrupts microtubules irreversibly.

Transforming growth factor-beta3 gene SfaN1 polymorphism in Korean nonsyndromic cleft lip and palate patients.

The nonsyndromic cleft lip and palate (NSCL/P) is a congenital deformity of multifactorial origin with a relatively high incidence in the oriental population. Various etiologic candidate genes have been reported with conflicting results, according to race and analysis methods. Recently, the ablation of the TGF-beta3 gene function induced cleft palates in experimental animals.

Adhesion of oral streptococci to experimental bracket pellicles from glandular saliva.

The aim of this study was to evaluate the functions of bracket pellicles as the binding receptors for Streptococcus mutans and Streptococcus gordonii. Four different types of orthodontic brackets were used: stainless steel, monocrystalline sapphire, polycrystalline alumina, and plastic. The bracket pellicles were formed by incubating orthodontic brackets with fresh submandibular-sublingual saliva or parotid saliva for 2 hours.

Effects of upper lip closing force on craniofacial structures.

Force generated by the perioral musculature is known to be a potent factor that can affect tooth position and malocclusion. To evaluate the influence of the force of the orbicularis oris muscle on incisor position, we determined the maximum and average strengths of the upper lip of male Class I malocclusion patients with a Y-meter, which was devised to measure the vertical closing force of the lip with a load cell. The skeletal structures and incisor angulation were recorded by lateral cephalograms.