• Journal of Periodontal and Implant Science
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• v.31 no.2
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• pp.371-388
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• 2001

A novel glucanhydrolase(DXAMase) from a mutant of Lipomyces starkeyi(KSM 22) has been shown effective in hydrolysis of mutan, reduction of mutan formation by Streptococcus mutans and removal pre-formed sucrose-dependentadherent microbial film and DXAMase has been strongly bound to hydroxyapatitie. These in vitro properties of Lipomyces starkeyi DXAMase are desirable for its application as a dental plaque control agent. This study was performed to determine the adjunctive oral hygiene benefits and safety of dextranase(Lipomyces starkeyi KSM 22 DXAMase)-containing mouthwash when used alongside normal tooth-brushing. This 6-month clinical trial was placebo-controlled double-blind design evaluating 1U/ml dextranase mouthwash and 0.12% chlorhexidine mouthwash. A total 39 systemically healthy subjects, who had moderate levels of plaque and gingivitis were included. At baseline, 1, 3 and 6 months, subjects were scored for plaque accumulation(Turesky modification of Quingley-Hein's plaque index), gingivitis status($L\ddot{o}e$ and Silness gingival index), and tooth stain(Area and severity index system by Lang et al). Additionally, oral mucosal examinations were performed and subjects questioned for adverse symptoms. Two weeks after pre-experiment examinations and a professional prophylaxis, the subjects provided with allocated mousewash and instructed to use 20-ml volumes for 30s twice daily after toothbrushing. All the groups showed significant increase in plaque accumulation since 1 month of experiment. During 6 months' period, the Dextranase mouthwash group showed the least increase in plaque accumulation, compared to the Chlorhexidine mouthwash and placebo groups. As for gingival inflammation, all the groups showed significant increase during 6 months of experiment. The Experimental group(Dextranase mouthwash) also showed the least increase in gingival index score, compared to the Positive control(Chlorhexidine mouthwash)as well as the Negative control(placebo)groups. Whereas the tooth stain was increased significantly in the Positive control group, compared to the baseline score and the Negative controlgroup since 3 months of mouthrinsing. It was significantly increased after 6 months in the Experimental group, still less severe than the Positive control group. As for the oral side effect, the Experimental group showed less tongue accumulation, bad taste, compared to the Positive control group. From these results, mouthrinsing with Lipomyces starkeyi KSM 22 dextranase provided adjunctive benefits to toothbrushing, comparable to 0.12% chlorhexidine mouthwash in inhibition of plaque accumulation and gingival inflammation and local side effects were if anything less frequent and less intense than chlorhexidine, with long-term use of the mouthwash. All data had provided positive evidence for Lipomyces starkeyi KSM 22 dextranase as an antiplaque agent and suggested that further development of dextranase formulations for plaque control are warranted.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.1
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• pp.66-74
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• 2019

Excessive wear causes many complications when untreated, so that accurate diagnosis, analysis and predictive treatment plan should be made, and through evaluation of vertical dimension and stepwise treatment, a stable inter-arch relationship can be set. For the long-term success of implant treatment, ideal position and angle of implant is important, and its importance increases especially in multiple implant cases. Therefore, thorough diagnosis and planning, accurate surgery and prosthodontic procedures are significant. In this case, a 68-year-old male patient with a loss of vertical dimension due to multiple tooth loss and overall tooth wear was planned with systematic analyses from the pre-treatment stage to rehabilitate vertical dimension. Full-mouth fixed rehabilitation with computer tomography guided implant surgery was performed to the newly set vertical dimension and attained satisfactory outcomes both functionally and esthetically.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.3
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• pp.280-290
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• 2021

Color stability of pulp-capping material is considered vital to the final aesthetic result since the material is placed in the coronal area. The purpose of this study was to compare the color stability of various pulp-capping materials by analyzing color change of tooth over time. A cavity was formed in the crown of the extracted premolar, and 4 types of pulp-capping materials were filled. Color assessment was performed with a spectrophotometer at different intervals: before placement; immediately after material placement; 1 day, 1 week, 2 weeks, 4 weeks, 8 weeks, 12 weeks, and 16 weeks after placement. Proroot white MTA^® and TheraCal LC^® showed a significant decrease in the L^* value and an increase in the ∆E^* value over time. In contrast, Biodentine^® and Well-Root^TM PT showed no significant change in the L^* value and maintained a steady ∆E^* value. The application of pulp-capping materials containing bismuth oxide as a radiopacifier may result in a color change of teeth. Long-term color stability of pulp-capping materials should be considered when treating teeth with thin enamel thickness or in aesthetically important area.

• The Journal of Korean Academy of Prosthodontics
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• v.62 no.2
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• pp.146-156
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• 2024

Implant assisted removable partial denture (IARPD) has been practiced in various forms for a long time, and among them, implant surveyed crown RPD is gaining predictability as well as being considered as a treatment option for patients with anatomical and financial disadvantages. The position of implant could be divided as posterior placement or anterior placement according to the purpose of the treatment and should be planned in consider to the alveolar ridge of patient, anticipated prognosis of remaining teeth, and opposing dentition. This case report describes a treatment for mandibular Kennedy class I partial edentulous patient with two implant-supported surveyed crown and implant assisted removable partial denture. Given the difficulty of posterior placement in this patient and the prognosis of the residual teeth, the plan was to place two implants in close proximity to the residual teeth, which were placed in the planned position, angle, and depth using guided surgery. The process of fabricating the fixed prosthesis was carried out in parallel with the maxillary edentulous tooth arrangement process to increase predictability, and when fabricating the localized tooth, the implant was designed in a form that allows the patient to perform functional movements by preventing excessive loading as the last supporting tooth, and was fabricated through a secondary impression process. Each treatment procedure was proceeded as planned, with aesthetically and functionally satisfactory results for both patient and operator.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.1
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• pp.42-49
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• 2021

This study aimed to evaluate the long-term outcomes of teeth treated with reattachment technique in children and adolescents. Twenty seven permanent anterior teeth from 21 patients treated with fragment reattachment were evaluated. Clinical photos and medical records were used to assess treatment outcomes. Effect of pulp treatment and the ratio of fragment on success rate were statistically analyzed. Detachment of fragment was observed in 17 teeth, and their duration of retention was 21.41 ± 23.39 months. Repeated trauma was found to be the most frequent causes of failure. Pulp treatment before reattachment did not affect the success rate (p > 0.05). The mean ratio of fragment was 0.482 ± 0.147, and the success rate was affected by the ratio of fragment (p = 0.018). The median retention time of the teeth was 72 months if the ratio was under 0.5, and 8 months for that of the others. A significant correlation was found between the ratio of fragment and retention time (p = 0.003). Reattachment can be a predictable treatment option for crown fracture in anterior teeth in children and adolescents when a fracture involves less than 50% of the clinical crown.

• Restorative Dentistry and Endodontics
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• v.34 no.4
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• pp.324-332
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• 2009

The purpose of this study was to investigate the effect of rigidity of post core systems on stress distribution by the theoretical technique, finite element stress-analysis method. Three-dimensional finite element models simulating an endodontically treated maxillary central incisor restored with a zirconia ceramic crown were prepared and 1.5 mm ferrule height was provided. Each model contained cortical bone, trabecular bone, periodontal ligament, 4 mm apical root canal filling, and post-and-core. Six combinations of three parallel type post (zirconia ceramic, glass fiber, and stainless steel) and two core (Paracore and Tetric ceram) materials were evaluated, respectively. A 50 N static occlusal load was applied to the palatal surface of the crown with a $60^{\circ}$angle to the long axis of the tooth. The differences in stress transfer characteristics of the models were analyzed. von Mises stresses were chosen for presentation of results and maximum displacement and hydrostatic pressure were also calculated. An increase of the elastic modulus of the post material increased the stress, but shifted the maximum stress location from the dentin surface to the post material. Buccal side of cervical region (junction of core and crown) of the glass fiber post restored tooth was subjected to the highest stress concentration. Maximum von Mises stress in the remaining radicular tooth structure for low elastic modulus resin core (29.21 MPa) was slightly higher than that for high elastic modulus resin core (29.14 MPa) in case of glass fiber post. Maximum displacement of glass fiber post restored tooth was higher than that of zirconia ceramic or stainless steel post restored tooth.

• The Journal of Advanced Prosthodontics
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• v.9 no.3
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• pp.224-231
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• 2017

PURPOSE. This study was designed to evaluate the teeth and dental implants during dental maintenance therapy over 3 years in different conditions after periodontal and dental prosthetic treatment. MATERIALS AND METHODS. 166 patients received maintenance therapy. 59 patients were treated with 2% minocycline-HCl ointment as local drug delivery (LDD) (L group) and 107 patients were treated without LDD (NL group). Clinical data was collected in maintenance period for evaluation. Patients were classified into groups depending on the application of LDD with maintenance therapy, the type of dental treatment before maintenance period (Pre-Tx), the frequency (F-MT), and regularity (R-MT) of maintenance therapy. RESULTS. The numbers of lost teeth (N-teeth, P=.003) and newly placed dental implants (N-implants, P=.022) are significantly different according to Pre-Tx. F-MT among patients who received surgical dental treatment before maintenance period showed statistical differences in N-teeth (P=.041), but not in N-implants (P=.564). All of the patients in L group showed high F-MT (F-MT1). In NL group, there were no statistical differences in N-teeth or N-implants according to F-MT or R-MT. In F-MT1 group, application of LDD made N-teeth significantly different from both Pre-Tx groups while no significant difference could be found in N-implant. Independent t-test and one-way ANOVA were selected for statistical analysis. CONCLUSION. The regular maintenance therapy and LDD can be effective for teeth during maintenance period. It is not only pharmacological efficacy in decreasing bacterial species that makes LDD a useful adjunct. Application of LDD also motivates patients to take adequate check-ups in the aspects of both frequency and regularity.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.3
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• pp.215-221
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• 2015

Treating patients with severely worn dentition often requires comprehensive prosthetic treatments. Oral rehabilitation and long-term stability could be achieved by analyzing the cause of the wear and changing vertical dimension. The temporary restoration procedure is executed and patient's adaptation is evaluated by long-term observation when treatment is accompanied with increasing vertical dimension. In this case, 54 year-old male presented with worn dentition and esthetic dissatisfaction. In oral manifestations, severely worn dentition with attrition and erosion is diagnosed. To evaluate change of vertical dimension, interocclusal rest space, facial appearance, pronunciation, clinical crown length, distance from incisor edge to labial vestibule are evaluated. Consequently, 2.5 mm increase of vertical dimension that based on articulator incisal pin is determined. After 8 weeks stabilization period with temporary prostheses, definitive prostheses are fabricated. After 6 months follow up period, satisfactory outcomes were achieved both in functional and esthetic aspects through this procedure.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.14 no.4
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• pp.327-339
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• 1992

This study was undertaken to investigate the effect of orthognathic surgery on occlusal force. The maximum bite force was measured in 26 dentofacial deformity patients, aged 14-26(mean age 20.3) years, before surgery and at IMF removal, 3, 6, and 12months postsurgery. To grope the correlation of bite force and skeletal change after orthognathic surgery, the cephalometric headplates were measured, tabulated and statistically analyzed. The results were as follows. 1. The presurgical maximum bite force was 13.7kg in upper first molar(rt. Side 12.7kg, it. Side 14.6kg). There was remarkable difference with that of normal occlusion. 2. The recovery of bite force was very significant in according to the operation method and the duration of IMF that was 7.6kg at IMF removal, 14.2kg at 3 months, 19.7kg at 6 months. 26.1kg at 12 months postsurgery. 3. To fasten the recovery and to increase the bite force after orthognathic surgery, the long IMF time and the injury to the masticatory muscle should be avoided by the internal rigid fixation and early physical exercise. 4. The bite force was positively correlated to the changes of mandibular plane angle, the angle between platatal plane and mandibular plan, the angle between occlusal plane and mandibular plane, and negatively correlated to the changes of mandibular body length in craniofacial structure. 5. There was no correlationship between bit force and mesial inclination of tooth long axis of first molar in this subject. 6. There was no correlation between the changes of bite force and the changes of mechanical advantage of the temporal and masseter muscle.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.1
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• pp.46-52
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• 2017

Provisional restoration plays an important role in the process of restoration with fixed partial denture by providing protection and restoring function and esthetics of abutment tooth. This is especially true in patients requiring use of provisional prosthesis for a long term. However, such situations may lead to higher possibility of provisional prosthesis fracture, and if expected so, reinforcement of provisional prosthesis should be considered. In this article, a patient requiring prosthetic treatment with increase of vertical dimension of occlusion was introduced. Due to increased vertical dimension of occlusion, the provisional restoration was expected to withstand relatively larger amount of load during a relatively long observation period. In order to minimize possible occurrence of fracture, reinforcement of the provisional restoration was sought by insertion of cast-metal framework and by using bis-acryl resin. The reinforced provisional restoration showed satisfactory results during the observation period of 4 months.