Orthodontic treatment using indirect bonding technique in periodontitis / 대한치주과학회지

Periodontal disease and/or loss of teeth brings pathologic tooth migration that can result in esthetic and occlusal problems. Diastema and general spacing of the teeth, particularly in the anterior segments of the dentition are frequently developed in individuals with advanced periodontal disease. Thus, the overall treatment plan for a patient with advanced periodontal disease often involves periodontal orthodontic combined therapy. Orthodontic treatment in adults with periodontal disease is restricted to tooth alignment with special caution. Indirect bonding can achieve accurate bracket placement. A 38 year old woman with adult periodontitis was treated by periodontal therapy. Subsequently, her diastema was orthodontically corrected by indirect bonding technique. It must be an appropriate case report of periodontal-orthodontic combined therapy.

The effect of a pulsed-Nd:YAG laser irradiation on microstructure of human gingiva / 대한치주과학회지

Since laser therapy has been applied to dentistry, many dental practitioners are very interested in laser therapy on various intraoral soft tissue lesions including gingival hyperplasia and aphthous ulcer. The purpose of the present study was to determine the therapeutic effect and the harmful effect of a pulsed-Nd:YAG laser irradiation on human gingival tissue. In twenty periodontal patients with gingival enlargement, the facial gingival surface of maxillary anterior teeth was randomly irradiated at various power of 1.0W(100mJ, 10Hz), 3.0W(100mJ, 30Hz) and 6.0W(150mJ, 40Hz) for 60 seconds by contact delivery of a pulsed-Nd:Y AG laser(EN.EL.EN060, Italy). Immediately after laser irradiation, the gingival tissues were surgically excised and prepared in size of 1mm3. Subsequently the specimens were processed for prefixation and postfixation, embedded with epon mixture, sectioned in 1micron thickness, stained with uranyl acetate and lead citrate, and observed under transmission electron microscope(JEM 100 CXII). Following findings were observed; 1. In the gingival specimens irradiated with 1.0W power, widening of intercelluar space and minute vesicle formation along the widened intercellular space were noted at the epithelial cells adjacent to irradiated area. 2. In the gingival specimens irradiated with 3.0W power, the disruption of cellular membrane, aggregation of cytoplasm, and loss of intercellular space were observed at the epithelial cells adjacent to irradiated area. 3. In the gingival specimens irradiated with 6.0W power, the disruption of nuclear and cellular membrane was observed at the epithelial cells adjacent to irradiated area. The ultrastructural findings of this study suggest that surgical application of a pulsed-Nd:YAG laser on human gingival tissue may lead somewhat delayed wound healing due to damage of epithelial cells adjacent to irradiated area.

Evaluation of cytotoxicity and bone affinity on the surface of a titanium phosphide / 대한치주과학회지

Dental implants have been developed for enhancement of osseointegration. Biocompatibility, bone affinity and surface characteristics of dental implants are very important factors for osseointegration. The aim of the present study was to determine the cytotoxicity and the bone affinity of titanium phosphide(Ti-P) implant material. The Ti-P surface was obtained by vacuum sintering of titanium within compacted hydroxyapatite powder. The composition and the chemical change of the surface were determined by Auger electron spectroscopy. The in vitro cytotoxicity was evaluated by the viability of the bone cells and macrophages obtained from chicken embryo and rat,s peritonium, respectively. For the comparative evaluation, 316L stainless steel, commercially pure titanium and Ti-P materials, prepared in size of 10.0mm in diameter and 5.0mm in height, were immersed separately in bone cells and macrophages for 10 days. For the evaluation of the in vivo bone affinity, 316L stainless steel, commercially pure titanium and Ti-P materials, prepared in size of 5.0mm in diameter and 10.0mm in length, were implanted after drilling in diameter 5.5mm in femurs of 2 dogs weighing 10Kg more or less. Six weeks after implantation the specimens were prepared for histopathological examination and were observed under light microscope. In comparison of in vitro bone cell viability, Ti-P and commercially pure titanium groups were not significantly different from control group(p>0.1), but 316L stainless steel group was significantly lower than control group(p0.1). In comparison of in vivo study, 316L stainless steel and commercially pure titanium showed fibrous encapsulation, but Ti-P showed remarkable new bone formation without any fibrous tissue. The results demonstrate that Ti-P has favorable biocompatibility and bone affinity, and suggest that dental implants with Ti-P surface may enhance osseointegration.

Effect of NaF iontophoresis and Nd:YAG laser irradiation on the abrasion-resistance of root surface / 대한치주과학회지

The purpose of this study was to evaluate the abrasion-resistance of root surface after NaF iontophoresis, Nd:YAG laser irradiation and combined treatment 50 anterior teeth with flat interproximal root surface that had been extracted due to periodontal destruction were selected. All teeth were treated by the same procedure as conventional periodontal root treatment, such as scaling and root planing, root conditioning with tetracycline HCl(100mg/ml, 5min). The pre-treatment weight of each tooth was measured by a dial scale(SHIMADEU Co., LIBROR EB-220HU, capacity 220.000 g, Japan). All teeth were divided into 5 groups as follows; Nd:YAG laser irradiation(group 1, 1 W, 100 mJ, 10Hz, fiberoptic-root surface distance=5mm, 10 sec.x6times, EL.EN.EN060, Italy); NaF iontophoresis(group 2, 150micronA, 4 min.); Nd:YAG laser irradiation following NaF iontophoresis(group 3); NaF iontophoresis following Nd:YAG laser irradiation(group 4); No treatment(control group). Electric toothbrushing (Oral-B, Brown Co., Germany) was conducted during 1 hour(10 min.x6 times). Subsequently post-treatment weight was remeasured by the same method as pre-treatment weight measurement. The difference of abrasion rate among all groups was statistically analyzed by ANOVA(SAS program). Following results were obtained; 1. The abrasion rate was significantly lower in Nd:YAG laser irradiation group than NaF iontophoresis group(p 0.05). 4. The abrasion rate was significantly lower in all experimental groups than control group(p < 0.001). The results suggest that combined treatment of Nd:YAG laser irradiation and NaF iontophoresis on exposed root surface after periodontal therapy can enhance the abrasion-resistance of root surface and may inhibit the root caries development.

A Scanning electron microscopic study of the dentinal tubule obliteration effect by the different irradiations of a pulsed Nd:YAG laser / 대한치주과학회지

Dentin hypersensitivity must be one of the most frequent postoperative complaints in periodontal patients. Obliterating the open dentinal tubules or decreasing the diameter of their orifices would, therefore, be an objective of treatment for hypersensitive teeth. The purpose of this study was to evaluate the effect of a pulsed Nd:YAG laser irradiation on obliteration of dentinal tubules and to determine any difference according to irradiation methods. The 45 posterior teeth that had been extracted due to periodontal disease were initially treated with tetracycline HCl(100 mg/ml, 4 min.) to remove the smear layer after root planing. The root surfaces were then irradiated by a pulsed Nd:YAG laser(EL.EN.EN060, Italy) by different laser beam spot size and different exposure condition; group 1: irradiated group by small spot(beam diameter=1mm, 1W, 2 sec) group 2: irradiated group by large spot(beam diameter=10mm, 1W, 200 sec) group 3: irradiated group by gradual increase of watt(from 0.3W to 1.0W), beam diameter=4mm group 4: irradiated group by fixed watt(1.0 W), beam diameter= 4mm control group: no irradiation but root planing and tetracycline HCl conditioning only. Additionally, the specimens were retreated with tetracycline HCl(100mg/ml, 4min.) to evaluate the stability of obliteration effect by Nd:YAG laser. Specimens were examined under the scanning electron microscope(JEOL, JSM-840A, Japan). Photomicrographs were taken at x4,000 magnification and were analyzed statistically. The results were as follows; 1. Scanning electron micrographs of root surface treated by tetracycline HCl alone(control group) showed widened, funnel-shaped dentinal tubules, while those of the root surface irradiated by various methods showed partially or completely obliterated dentinal tubules and various surface alterations, eg, flat, multiple pitted, melted and resolidified surface at the same energy density. 2. There was no significant difference in the obliteration effect of dentinal tubules between group 1 and group 2, and between group 3 and group 4(p>0.05). 3. The obliteration effect of dentinal tubules by a Nd:YAG laser irradiation was relatively stable to tetracycline HCl. The results demonstrate that a pulsed Nd:YAG laser irradiation within 1.0W, regardless of irradiation methods, can obliterate dentinal tubules effectively.