Comprehensive orthodontic treatment of a young girl with an odontogenic keratocyst and impacted teeth in the mandible

Odontogenic keratocysts (OKCs) are one of the most aggressive cysts in the oral and maxillofacial area because of their high recurrence rate and infiltrative behavior. In growing patients with OKCs, a radical treatment approach might cause numerous complications, including the disturbance of jaw growth and loss of the involved tooth. This case report describes successful comprehensive orthodontic treatment combined with marsupialization of the cyst in a young girl who exhibited an OKC with impacted teeth. The 10-year-old girl presented with an OKC extending from the mandibular symphysis through the left mandibular body, with ectopic impaction of the mandibular left canine and first premolar, as well as congenitally missing bilateral mandibular second premolars. Interestingly, spontaneous improvement of the positions of the ectopic impacted teeth, along with a reduction in the size of the cyst, occurred during marsupialization. The sequential use of removable and fixed appliances enabled orthodontic traction of the impacted teeth. The treatment outcome was stable at 2.5 years after the end of the treatment. We speculate that comprehensive orthodontic treatment combined with marsupialization can be an effective treatment strategy for patients with OKCs, especially when they are encountered in young, growing patients with impacted teeth.ope

Resin-Based Sealant with Bioactive Glass and Zwitterionic Material for Remineralisation and Multi-Species Biofilm Inhibition

Since pits and fissures are the areas most commonly affected by caries due to their structural irregularity, bioactive resin-based sealant (RBS) may contribute to the prevention of secondary caries. This study aims to investigate the mechanical, physical, ion-release, enamel remineralisation, and antibacterial capabilities of the novel RBS with bioactive glass (BAG) and 2-methacryloyloxyethyl phosphorylcholine (MPC). For the synthesis, 12.5 wt% BAG and 3 wt% MPC were incorporated into RBS. The contact angle, flexural strength, water sorption, solubility, and viscosity were investigated. The release of multiple ions relating to enamel remineralisation was investigated. Further, the attachments of bovine serum albumin, brain heart infusion broth, and Streptococcus mutans on RBS were studied. Finally, the thickness and biomass of a human saliva-derived microsm biofilm model were analysed before aging, with static immersion aging and with thermocycling aging. In comparison to commercial RBS, BAG+MPC increased the wettability, water sorption, solubility, viscosity, and release of multiple ions, while the flexural strength did not significantly differ. Furthermore, RBS with MPC and BAG+MPC significantly reduced protein and bacteria adhesion and suppressed multi-species biofilm attachment regardless of the existence of aging and its type. The novel RBS has great potential to facilitate enamel remineralisation and suppress biofilm adhesion, which could prevent secondary dental caries.ope

Incorporation of zwitterionic materials into light-curable fluoride varnish for biofilm inhibition and caries prevention

We incorporated zwitterionic materials into light-curable fluoride varnish (LCFV) in order to inhibit biofilm accumulation and prevent dental caries, and the properties of LCFV with three different zwitterionic materials, namely, 2-methacryloyloxyethyl phosphorylcholine (MPC), carboxybetaine methacrylate (CBMA), and sulfobetaine methacrylate (SBMA) polymers (each at a weight percentage of 3%), were compared; unmodified LCFV without any zwitterionic material was used as a control. Material properties including film thickness and degree of conversion (DC) of each type of LCFV were evaluated. In addition, protein-repellent effects and inhibitory effects on Streptococcus mutans adhesion and saliva-derived biofilm accumulation of LCFV were estimated. Finally, the preventive effect of LCFV on enamel demineralization was assessed in vitro on extracted human teeth specimens stored in S. mutans-containing medium. The film thickness of LCFV significantly decreased with the incorporation of zwitterionic materials compared to the control LCFV, whereas there were no significant differences in the DC among all of the LCFV groups. Furthermore, the amount of adsorbed protein, adherent S. mutans colony-forming unit (CFU) counts, and saliva-derived biofilm thickness and biomass were all significantly lower for LCFV with incorporated zwitterionic materials compared with the control. All LCFV groups including the control showed certain preventive effects against enamel demineralization during a 14-day immersion in the medium with S. mutans and sucrose, and the depth of demineralization was significantly lower in LCFV with zwitterionic materials than in the control. Thus, the incorporation of zwitterionic materials such as MPC, CBMA, and SBMA appears to confer superior antifouling effects to LCFV.ope

A Case Study of Facial Asymmetric Patients Using Similarity Index, a New Method for Evaluating Three-Dimensional and Geometric Morphological Symmetry of the Mandible

To evaluate the stereoscopically structural symmetry of the mandible, the landmark-based analyses that have been accustomed to two-dimensional images like lateral and posteroanterior cephalograms, even with three-dimensional (3D) cone-beam computed tomography, have definite limitations. The newly developed similarity index (SI) can make it easier to intuitively assess 3D mandibular asymmetry. An 18-year-old female with skeletal Class III and facial asymmetry underwent bimaxillary orthognathic surgery. The total treatment time was 16 months including pre-and post-surgical orthodontic treatment. SI was used to evaluate the patient’s asymmetry of the mandible before and after surgery. The feasibility of SI could be validated in diagnosing the asymmetry before surgery and evaluating the residual asymmetry after surgery.ope

Time-dependent biological effects after ultraviolet light and nonthermal atmospheric pressure plasma treatment on aged titanium surface

Dept. of Dentistry/박사Ultraviolet light (UV) or nonthermal atmospheric pressure plasma jet (NTAPPJ) treatment has been known to modify the physicochemical properties of titanium implants without altering topography and to enhance its biological activity, such as promoting blood protein and osteoblastic cell attachment, thereby increasing the formation of new bone. However, few studies have evaluated whether there are differences in time-dependent biological activity of treatment on the titanium surface between UV and NTAPPJ. Therefore, we evaluated time-dependent biological effects after UV and NTAPPJ treatment on aged titanium surface compared with that of untreated titanium surface. Grade IV machined surface titanium discs (12-mm diameter) were used immediately and stored up to 28 days after UV irradiation for 15 minutes or NTAPPJ treatment for 10 minutes. Changes of surface characteristics over time were evaluated using scanning electron microscopy, surface profiling, contact angle analysis, X-ray photoelectron spectroscopy, and surface zeta-potential. Changes in biological activity over time were as determined by analyzing bovine serum albumin adsorption, MC3T3-E1 early adhesion and morphometry, and alkaline phosphatase (ALP) activity between groups. We found no differences in the effects of treatment on titanium between UV and NTAPPJ regardless of the storage time (P > 0.05). Photocatalytic activity by UV and higher production of reactive oxygen species (ROS) such as hydroxyl radical or synergistic ROS/UV action by NTAPPJ removed the surface hydrocarbon and altered the surface from negatively charged hydrophobic (bioinert) to positively charged hydrophilic (bioactive) surfaces (P 0.05). However, ALP activity of the UV- and NTAPPJ-treated groups was significantly increased when compared with that of the untreated titanium (P < 0.05). Based on the results of this study, there was no significant difference in the biological effect of treatment on the titanium surface between UV and NTAPPJ over time. When compared to immediately after treatment, these treatment effects decreased with time. However, UV and NTAPPJ treatment can enhance the biological activity of aged titanium surface compared with that of untreated titanium regardless of the storage time. Future in vivo studies are necessary to confirm whether these results can be applied in real clinical situations in the medical and dental fields. 자외선 (UV) 또는 저온 대기압 플라즈마 (NTAPPJ) 처리는 타이타늄 임플란트 표면의 형태적인 변화없이 물리 화학적 특성을 변화시키고, 혈장 단백질 및 골모 세포의 부착을 촉진시켜 새로운 골의 형성을 증가시키는 것과 같은 타이타늄의 생물학적 활성도를 향상 시키는 것으로 알려져 왔다. 그러나, UV와 NTAPPJ 간에 처리 후 시간에 따른 타이타늄 표면의 생물학적 활성도의 차이 여부를 평가한 연구는 거의 없었다. 따라서 본 연구는 UV와 NTAPPJ 처리 후 시간에 따른 타이타늄의 생물학적 활성도의 변화를 아무런 처리하지 않은 타이타늄과 비교하여 평가하였다. 지름 12 mm의 평활면 grade IV 타이타늄 디스크에 UV를 15분간 또는 NTAPPJ를 10분간 처리한 후 즉시 또는 28일 동안 보관한 뒤 시편으로 사용하였다. 시간에 따른 타이타늄 표면의 특성 변화를 평가하기 위해서 주사 전자 현미경, 표면 조도계, 접촉각 측정기, 광전자 분광기, 제타 전위 측정기를 이용하였다. 타이타늄의 시간에 따른 생물학적 활성도의 변화를 평가하기 위해서 소 혈청 알부민 부착률, 백서 골모 유사 세포인MC3T3-E1의 초기 부착률, 세포 골격 발달 수준 및 알카라인 포스파타제 (ALP)의 활성도를 분석하였다. UV와 NTAPPJ가 타이타늄 표면에 미치는 효과는 보관 기간에 상관없이 서로 간에 유의한 차이를 보이지 않았다 (P > 0.05). UV에 의한 광촉매 현상과 NTAPPJ 에 의한 하이드록실 라디칼과 같은 활성 산소종 (ROS)의 증가 또는 ROS/UV의 상승 효과는 표면의 탄화 수소를 제거하였고, 표면을 음극의 소수성 (생체 불활성)에서 양극의 친수성 (생체 활성)으로 변화시켰다 (P 0.05). 그러나, UV와 NTAPPJ 처리한 군의 ALP 활성도는 아무런 처리하지 않은 타이타늄과 비교하였을 때 유의하게 증가하였다 (P < 0.05). 본 연구의 결과를 토대로, UV와 NTAPPJ가 타이타늄 표면에 미치는 생물학적 효과는 시간에 상관없이 서로 간에 유의한 차이를 보이지 않았다. 처리 직후와 비교하였을 때, 이들 처리 효과는 시간이 지날수록 감소하였다. 그러나 U...ope

Enamel Demineralization Resistance and Remineralization by Various Fluoride-Releasing Dental Restorative Materials

The aim of this study is to investigate the resistance of various fluoride-releasing restorative materials against the demineralization and remineralization of enamel surfaces, including those that have been recently introduced to the market. Three different fluoride-releasing restorative materials were considered: glass ionomer (FI), resin-modified glass ionomer (RL), and an alkasite restorative material (CN). The acid neutralization ability was investigated using pH measurement, and the concentrations of released fluoride and calcium ions were measured. Finally, the demineralization resistance and remineralization effects of enamel were observed using a microhardness tester and SEM. CN showed an initial substantial increase in pH followed by a steady increase, with values higher than those of the other groups (p < 0.05). All three groups released fluoride ions, and the CN group released more calcium ions than the other groups (p < 0.05). In the acid resistance test, from the microhardness and SEM images, the CN group showed effective resistance to demineralization. In the remineralization test, the microhardness results showed that the FI and CN groups recovered the microhardness from the values of the demineralized enamel surface (p < 0.05). This was confirmed by the SEM images from remineralization tests; the CN group showed a recovered demineralized surface when immersed in artificial saliva for 7 days. In conclusion, alkasite restorative material can be an effective material when used in cariogenic environments.ope

Surface Characteristics and Microbiological Analysis of a Vat-Photopolymerization Additive-Manufacturing Dental Resin

The wide application of additive manufacturing in dentistry implies the further investigation into oral micro-organism adhesion and biofilm formation on vat-photopolymerization (VP) dental resins. The surface characteristics and microbiological analysis of a VP dental resin, printed at resolutions of 50 μm (EG-50) and 100 μm (EG-100), were evaluated against an auto-polymerizing acrylic resin (CG). Samples were evaluated using a scanning electron microscope, a scanning white-light interferometer, and analyzed for Candida albicans (CA) and Streptococcus mutans (SM) biofilm, as well as antifungal and antimicrobial activity. EG-50 and EG-100 exhibited more irregular surfaces and statistically higher mean (Ra) and root-mean-square (rms) roughness (EG-50-Ra: 2.96 ± 0.32 µm; rms: 4.05 ± 0.43 µm/EG-100-Ra: 3.76 ± 0.58 µm; rms: 4.79 ± 0.74 µm) compared to the CG (Ra: 0.52 ± 0.36 µm; rms: 0.84 ± 0.54 µm) (p < 0.05). The biomass and extracellular matrix production by CA and SM and the metabolic activity of SM were significantly decreased in EG-50 and EG-100 compared to CG (p < 0.05). CA and SM growth was inhibited by the pure unpolymerized VP resin (48 h). EG-50 and EG-100 recorded a greater irregularity, higher surface roughness, and decreased CA and SM biofilm formation over the CG.ope

Prediction of Fishman's skeletal maturity indicators using artificial intelligence

The present study aimed to evaluate the performance of automated skeletal maturation assessment system for Fishman's skeletal maturity indicators (SMI) for the use in dental fields. Skeletal maturity is particularly important in orthodontics for the determination of treatment timing and method. SMI is widely used for this purpose, as it is less time-consuming and practical in clinical use compared to other methods. Thus, the existing automated skeletal age assessment system based on Greulich and Pyle and Tanner-Whitehouse3 methods was further developed to include SMI using artificial intelligence. This hybrid SMI-modified system consists of three major steps: (1) automated detection of region of interest; (2) automated evaluation of skeletal maturity of each region; and (3) SMI stage mapping. The primary validation was carried out using a dataset of 2593 hand-wrist radiographs, and the SMI mapping algorithm was adjusted accordingly. The performance of the final system was evaluated on a test dataset of 711 hand-wrist radiographs from a different institution. The system achieved a prediction accuracy of 0.772 and mean absolute error and root mean square error of 0.27 and 0.604, respectively, indicating a clinically reliable performance. Thus, it can be used to improve clinical efficiency and reproducibility of SMI prediction. © 2023. The Author(s).ope

Development of 1-Frame 3-D PTV and its Application to Measurement of a Backward-Facing Step Flow

In this paper, a new three-dimensional PTV(Particle Tracking Velocimetry) technique using the concept of match probability between two-field (1-Frame) images has been developed to obtain an instantaneous three-dimensional velocity field of high speed flows. The measuring system consists of three CCD (Charge Coupled Device) cameras, an optical instrument called AOM (Acousto-Optical Modulator), a digital image grabber, and a host computer. For verification of the developed technique, moving particles which are spatially installed on a rotating plate are tracked by the developed technique and are compared with those of actual rotating speed. The developed 1-Frame 3-D PTV system is applied to the measurement of turbulent backward-facing step flow and the results are compared with those of a Panoramic-PIV system which has been developed in this study. The performance of the developed algorithm is verified by a benchmark test using the three-dimensional velocity vectors obtained by the experiment on the backward-facing step flow. An uncertainty analysis associated with the present 1-Frame 3-D PTV technique is quantitatively evaluated. The capability of the developed technique is validated by probing three-dimensional velocity fluctuation components (u', v', w') of a relatively high speed backward-facing step flow

Influence of Orthodontic Anchor Screw Anchorage Method on the Stability of Artificial Bone: An In Vitro Study

This study aims to compare the torque values for various lengths of the titanium-based orthodontic anchor screw (OAS), different anchorage methods and varying artificial bone densities after predrilling. Furthermore, the effects of these parameters on bone stability are evaluated. A total of 144 OASs were prepared with a diameter of 1.6 mm and heights of 6, 8 and 10 mm. Artificial bones were selected according to their density, corresponding to Grades 50, 40 and 30. Torque values for the automatic device and manual anchorage methods exhibited a statistically significant difference for the same-sized OAS, according to the bone density of the artificial bones (p 0.05). When the torque values of both anchorage methods were statistically compared with the mean difference for each group, the results of the manual anchorage method were significantly higher than those of the automatic device anchorage method (p < 0.05). A statistically significant difference was observed in the bone stability resulting from different OAS anchorage methods and artificial bone lengths. These findings suggest that the automatic anchorage method should be used when fixing the OAS.ope