• Journal of Periodontal and Implant Science
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• v.49 no.3
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• pp.171-184
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• 2019

Purpose: To evaluate the effects of intra-alveolar socket grafting, subepithelial connective tissue grafts, and individualized abutments on peri-implant hard and soft tissue outcomes following immediate implant placement. Methods: This randomized experimental study employed 5 mongrel dogs, with 4 sites per dog (total of 20 sites). The mesial roots of P3 and P4 were extracted in each hemimandible and immediate dental implants were placed. Each site was randomly assigned to 1 of 4 different treatment groups: standardized healing abutment (control group), alloplastic bone substitute material (BSS) + standardized healing abutment (SA group), BSS + individualized healing abutment (IA group), and BSS + individualized healing abutment + a subepithelial connective tissue graft (IAG group). Clinical, histological, and profilometric analyses were performed. The intergroup differences were calculated using the Bonferroni test, setting statistical significance at P<0.05. Results: Clinically, the control and SA groups demonstrated a coronal shift in the buccal height of the mucosa ($0.88{\pm}0.48mm$ and $0.37{\pm}1.1mm$, respectively). The IA and IAG groups exhibited an apical shift of the mucosa ($-0.7{\pm}1.15mm$ and $-1.1{\pm}0.96mm$, respectively). Histologically, the SA and control groups demonstrated marginal mucosa heights of $4.1{\pm}0.28mm$ and $4.0{\pm}0.53mm$ relative to the implant shoulder, respectively. The IA and IAG groups, in contrast, only showed a height of 2.6mm. In addition, the height of the mucosa in relation to the most coronal buccal bone crest or bone substitute particles was not significantly different among the groups. Volumetrically, the IA group ($-0.73{\pm}0.46mm$) lost less volume on the buccal side than the control ($-0.93{\pm}0.44mm$), SA ($-0.97{\pm}0.73mm$), and IAG ($-0.88{\pm}0.45mm$) groups. Conclusions: The control group demonstrated the most favorable change of height of the margo mucosae and the largest dimensions of the peri-implant soft tissues. However, the addition of a bone substitute material and an individualized healing abutment resulted in slightly better preservation of the peri-implant soft tissue contour.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.3
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• pp.263-270
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• 2019

Current trends in restorative dentistry focus on improving the esthetics and keeping the sound dental tissues as long as possible. The aims of this case report were to describe the successful outcome of cubic-phase zirconia laminate veneers for a patient with isolated microdontia by using a digital workflow, and to describe their clinical implications. A 15-year-old female who had isolated microdontia in combination with spacing visited Ajou University Dental Hospital for esthetic treatment. In this case, 6 maxillary anterior teeth were restored with cubic-phase zirconia laminate veneers without tooth structure removal by using a digital impression, computer-aided design (CAD) software, and computer-aided manufacturing (CAM) procedures. At 6-month follow-up, no distinct mechanical and biological complications were detected and the prostheses exhibited satisfactory esthetics and functions. Due to its favorable tissue responses and enhanced translucency, cubic-phase zirconia can be a suitable strategy for a noninvasive esthetic approach.

• Journal of Periodontal and Implant Science
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• v.49 no.4
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• pp.215-227
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• 2019

Purpose: To histologically characterize periodontal healing at 8 weeks in surgically created dehiscence defects in beagle dogs that received a collagen matrix with periodontal ligament (PDL) progenitor cells. Methods: The bilateral maxillary premolars and first molars in 6 animals were used. Standardized experimental dehiscence defects were made on the buccal side of 3 premolars, and primary culturing of PDL progenitor cells was performed on the molars. Collagen matrix was used as a scaffold and a delivery system for PDL progenitor cells. The experimental sites were grafted with collagen matrix (COL), PDL progenitor cells with collagen matrix (COL/CELL), or left without any material (CTL). Histologic and histomorphometric analyses were performed after 8 weeks. Results: The defect height from the cementoenamel junction to the most apical point of cementum removal did not significantly differ across the CTL, COL, and COL/CELL groups, at $4.57{\pm}0.28$, $4.56{\pm}0.41$, and $4.64{\pm}0.27mm$ (mean ${\pm}$ standard deviation), respectively; the corresponding values for epithelial adhesion were $1.41{\pm}0.51$, $0.85{\pm}0.29$, and $0.30{\pm}0.41mm$ (P<0.05), the heights of new bone regeneration were $1.32{\pm}0.44$, $1.65{\pm}0.52$, and $1.93{\pm}0.61mm$ (P<0.05), and the cementum regeneration values were $1.15{\pm}0.42$, $1.81{\pm}0.46$, and $2.57{\pm}0.56mm$ (P<0.05). There was significantly more new bone formation in the COL/CELL group than in the CTL group, and new cementum length was also significantly higher in the COL/CELL group. However, there were no significant differences in the width of new cementum among the groups. Conclusions: PDL progenitor cells carried by a synthetic collagen matrix may enhance periodontal regeneration, including cementum and new bone formation.

• Journal of Periodontal and Implant Science
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• v.48 no.6
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• pp.347-359
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• 2018

Purpose: Periodontitis and rheumatoid arthritis (RA) share a similar inflammatory pathogenesis. Porphyromonas gingivalis (Pg) can induce anticyclic-citrullinated peptide autoantibodies (anti-CCP antibodies), a key factor in the development of RA. This study aimed at evaluating the relationships between the 2 diseases and identifying the clinical implications thereof, with a focus on periodontal pathogens in Korean adults. Methods: A total of 260 RA patients and 86 age- and sex-matched control patients without arthritis were enrolled in this prospective cross-sectional study. Periodontal indices and the prevalence and amount of periodontal pathogens were compared between the groups. Correlations between periodontal and RA indices were examined, as were correlations between 9 periodontal pathogens and RA indices. Results: The RA group had significantly higher values than the control group for all investigated periodontal indices (P<0.05) except the number of teeth. The gingival index (GI) was correlated with the disease activity score 28 (DAS28) (r=0.125, P=0.049), RA disease duration (r=0.253, P<0.001), erythrocyte sedimentation rate (ESR) (r=0.162, P=0.010), and anti-CCP antibody titer (r=0.205, P=0.004). Probing pocket depth (PPD) was correlated with ESR (r=0.139, P=0.027) and anti-Pg antibody titer (r=0.203, P=0.001). Bleeding on probing (BOP) was correlated with DAS28 (r=0.137, P=0.030), RA disease duration (r=0.202, P=0.001), ESR (r=0.136, P=0.030), anti-Pg antibody titer (r=0.177, P=0.005), and anti-CCP antibody titer (r=0.188, P=0.007). Clinical attachment level (CAL) and periodontitis severity were correlated with anti-Pg antibody titer (the former r=0.201, P=0.002; the latter r=0.175, P=0.006). The quantity of Pg was positively correlated with the serum anti-Pg antibody titer (r=0.148, P=0.020). Conclusions: The GI, BOP, and PPD showed positive relationships with several RA indices. The anti-Pg antibody titer had positive relationships with PPD, BOP, CAL, and periodontitis severity. Thus, increasing values of periodontal indices could be used as a risk indicator of disease development in RA patients, and an increasing anti-Pg antibody titer could be considered as a warning sign in RA patients suffering with periodontitis.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.1
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• pp.81-87
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• 2019

Patients with Down's syndrome have several dental complications such as small teeth caused by underdevelopment of dentin and enamel, periodontitis, agenesis of teeth, prolonged retention of primary teeth and malocclusion due to narrow palate. Removable denture with maxillary double crowns would be a good treatment option to solve the problems of the patient with Down's syndrome. Double crowns compensate the insufficient support and retention of denture and easily solve the cross bite problem. Double crowns also allow easy repair of denture in case of abutment teeth extraction. In this case, 26-year-old female patient with Down's syndrome and dental phobia had small number of teeth with enamel hypoplasia, prolonged retention of primary teeth and dental cross bite. Prosthetic treatment was done using removable denture with double crowns in the maxilla. In the mandible, teeth preparation was done on enamel margin without anesthesia. Anterior laminate and posterior complete zirconia crown restorations were performed. As a result, the cross bite was effectively corrected by denture with double crowns. Pronunciation and appearance were also improved without extraction of teeth and dental anesthesia.

• Journal of Periodontal and Implant Science
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• v.48 no.6
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• pp.360-372
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• 2018

Purpose: It has been suggested that resonance frequency analysis (RFA) can measure changes in the stability of dental implants during osseointegration. This retrospective study aimed to evaluate dental implant stability at the time of surgery (primary stability; PS) and secondary stability (SS) after ossseointegration using RFA, and to investigate the relationship between implant stability and cortical bone thickness. Methods: In total, 113 patients who attended the Tohoku University Hospital Dental Implant Center were included in this study. A total of 229 implants were placed in either the mandibular region (n=118) or the maxilla region (n=111), with bone augmentation procedures used in some cases. RFA was performed in 3 directions, and the lowest value was recorded. The preoperative thickness of cortical bone at the site of implant insertion was measured digitally using computed tomography, excluding cases of bone grafts and immediate implant placements. Results: The mean implant stability quotient (ISQ) was $69.34{\pm}9.43$ for PS and $75.99{\pm}6.23$ for SS. The mandibular group had significantly higher mean ISQ values than the maxillary group for both PS and SS (P<0.01). A significant difference was found in the mean ISQ values for PS between 1-stage and 2-stage surgery (P<0.5). The mean ISQ values in the non-augmentation group were higher than in the augmentation group for both PS and SS (P<0.01). A weak positive correlation was observed between cortical bone thickness and implant stability for both PS and SS in all cases (P<0.01). Conclusions: Based on the present study, the ISQ may be affected by implant position site, the use of a bone graft, and cortical bone thickness before implant therapy.

• The Journal of the Convergence on Culture Technology
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• v.5 no.2
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• pp.123-138
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• 2019

The clinical institution of some dental hygiene students and the degree of practice and performance according to the practice contents are identified, so as to develop clinical practice guidelines and to improve the education of universities and practical institutions. From November 2016 to March 2017, the questionnaire was prepared by self-inclusion after explaining the purpose of research and how to prepare questionnaire to some dental hygiene students. This material has been analyzed using PASW Statistics 18.0. As for the clinical practice content items of basic care and infection control, the frequency of "execution" among practice methods was high, and the distribution rate was high in oral evil face radiation, preventive dentistry, prosthesis, periodontology, orthodontics, and oral internal medicine. The conservation department has conducted various practical methods such as "executing," "observing" and "preparing." Oral surgery showed similar distribution rates, such as "observation," "preparation," and "execution" in the "preparation and cooperation of the feet." In pediatric dentistry, "observation" was the most common practice, and among them, "observation," "preparation," and "execution" were performed in "preparation and cooperation for infantile development." In addition, students with more experience in clinical practice showed statistically significant differences in basic care, oral hygiene, preventative dentistry, conservation, dental dentistry, oral surgery, orthodontics, and oral internal medicine(p<0.05). Most clinical practice shows that it is more observable than performed.It is expected that the goal of clear clinical practice content should be set by grade or number of clinical practice experiences, as well as the practice method that can be performed by the trainees.

• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.1
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• pp.29-37
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• 2019

The purpose of this study was to investigate the characteristics of intrusion in primary dentition and to evaluate factors influencing complications of primary and permanent dentition during long-term follow-up period. 61 patients (84 teeth) were selected in this study. Medical records of 61 patients were reviewed and age, gender, cause of injury, site of injury, severity of traumatic injury, other injuries associated with trauma, treatment method, and complications of primary and permanent dentition were examined. Collected data were statistically evaluated using Chi-square test and Fisher's exact test. Intrusion in primary anterior teeth was predominant in boys over girls and fall was the most common cause of trauma. It was most common at home and occurred most in the primary maxillary central incisors. Severity had an effect on the incidence of sequelae in permanent successors (p = 0.014). The incidence of complications was significantly lower in patients with soft tissue injuries than in patients with other periodontal injuries (p = 0.000).

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.2
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• pp.150-159
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• 2019

Nowadays, dental implant is one of the widely used treatment options for edentulous patients. Recently, a method of improving the accuracy of implant surgery using an implant surgical guide has been introduced and widely used in order to accurately place the implant in a proper position. Full-guided and half-guided implant surgery can be distinguished according to the level of surgical guide application during the implant surgery. It is true that full-guided implant surgery exhibits higher accuracy, but half- guided implant surgery is often performed in a clinical situation due to the factors such as the circumstances of the operation. A partially edentulous patient who lost teeth due to tooth fracture and periodontal disease was treated using implant and fixed prosthesis. Half-guided implant surgery was performed using an implant surgical guide during implant surgery, the accuracy of implant placement was analyzed.

• Journal of Periodontal and Implant Science
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• v.49 no.1
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• pp.2-13
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• 2019

Purpose: The aim of this study was to conduct a histologic evaluation of irradiated calvarial defects in rats 4 weeks after applying fibroblast growth factor-2 (FGF-2) with hyaluronan or biphasic calcium phosphate (BCP) block in the presence or absence of adjunctive hyperbaric oxygen (HBO) therapy. Methods: Twenty rats were divided into HBO and non-HBO (NHBO) groups, each of which was divided into FGF-2 and BCP-block subgroups according to the grafted material. Localized radiation with a single 12-Gy dose was applied to the calvaria of rats to simulate radiotherapy. Four weeks after applying this radiation, 2 symmetrical circular defects with a diameter of 6 mm were created in the parietal bones of each animal. The right-side defect was filled with the materials mentioned above and the left-side defect was not filled (as a control). All defects were covered with a resorbable barrier membrane. During 4 weeks of healing, 1 hour of HBO therapy was applied to the rats in the HBO groups 5 times a week. The rats were then killed, and the calvarial specimens were harvested for radiographic and histologic analyses. Results: New bone formation was greatest in the FGF-2 subgroup, and improvement was not found in the BCP subgroup. HBO seemed to have a minimal effect on new bone formation. There was tendency for more angiogenesis in the HBO groups than the NHBO groups, but the group with HBO and FGF-2 did not show significantly better outcomes than the HBO-only group or the NHBO group with FGF-2. Conclusions: HBO exerted beneficial effects on angiogenesis in calvarial defects of irradiated rats over a 4-week healing period, but it appeared to have minimal effects on bone regeneration. FGF-2 seemed to enhance new bone formation and angiogenesis, but its efficacy appeared to be reduced when HBO was applied.