• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.2
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• pp.119-126
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• 2012

State of problem: Cement-retained implant-supported prostheses are routinely used in dentistry. The use of high strength cements has become more popular with the increasing confidence in the stability of the implant-abutment screw connection and the high survival rates of osseointegrated implants. No clinical data on retention of metal copings using CAD/CAM. To evaluate retention of metal copings using CAD/CAM system bonded to short titanium abutment with four different cements and compare retentive strength of metal copings with sandblasting or without sandblasting before cementation. Forty titanium abutment blocks were fabricated and divided into 4 groups of 10 samples each. Forty metal copings with occlusal hole to allow for retention testing were fabricated using CAD/CAM technology. The four cements were Fujicem(Fuji, Japan), Maxcem Elite(Kerr, USA), Panavia F2.0(Kurarary, Japan) and Superbond C&B(Sunmedical, Japan). The copings were cemented on the titanium abutment according to manufacture's recommendation. All samples were stored for 24h at 37oC in 100% humidity and tested for retention using universal testing machine(Instron) at a crosshead speed of 1.0mm/min. Force at retentive failure was recorded in Newton. The mode of failure was also recorded. Means and standard deviations of loads at failure were analyzed using ANOVA and Paired t-test. Statistical significance was set at P<0.05. Panavia F2.0 provided significantly higher retentive strength than Fujicem, Maxcem Elite(P<0.05). Sandblasting significantly increased bond strength(P<0.05). The mode of failure was cement remaining principally on metal copings. Within the limitation of this study, Panavia F2.0 showed significantly stronger retentive strength than Fujicem, Maxcem Elite(p<0.05). The Ranking order of the cements to retain the copings was Panavia F2.0, Fujicem = Maxcem Elite. Sandblasting significantly increased bond strength(P<0.05). The retentive strength of metal copings on implant abutment were influenced by surface roughness and type of cements.

• Journal of Dental Rehabilitation and Applied Science
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• v.20 no.1
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• pp.31-41
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• 2004

The osseointegration in implant therapy is achieved following general wound healing mechanism. Platelet play a major role in wound healing process. In addition to blood clot formation, they secrete many growth factors which regulate the attachment, proliferation and differentiation of nearly all cell types. The use of these growth factors is now known to be very effective methods to improve the cellular activity. Platelet-rich plasma which is made with the newly developed technique concentrating platelets 3-folds or more is also proven to be very effective method to stimulate and accelerate the healing of bone and soft tissue. Previous study proved that platelet-rich plasma enhanced the cellular attachment by inducing fibronectin, vitronectin from osteoblast. So, this study was aimed to investigate the effect of platelet-rich plasma on the cellular proliferation and differentiation in vitro. The effect on the proliferation was evaluated by MTT assay. To evaluate autocrine and paracrine effect, conditioned medium was made and compared. By measuring alkaline phosphatase activity, the effect on the cellular differentiation was evaluated. The results were as following: The cellular proliferation of osteoblast cell line increased depending on the concentration of platelet-rich plasma and conditioned medium. The alkaline phosphatase activity increased depending on the concentration of platelet-rich plasma and conditioned medium. These findings imply that platelet-rich plasma enhance the cellular proliferation and differentiation and maximize the cellular activity by using the autocrine and paracrine effect.

• Journal of Dental Rehabilitation and Applied Science
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• v.34 no.2
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• pp.63-71
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• 2018

Prosthetic restorations through implants were popularized, and they became routine treatments. Small accessories used in the implant prosthodontic procedure are more likely to slip or fall off the dentist's hands. If the dental appliance or material passes into the upper gastrointestinal tract, there is a high possibility of excretion to the outside of the body without complications, but serious complications may occur depending on the type of foreign body. If the foreign body is passed to the airway, it is an emergency situation, and if it is not done properly, it can be fatal. The purpose of this review report is to investigate the process of foreign body ingestion or aspiration during dental treatment, and the method of prevention and treatment.

• Journal of Periodontal and Implant Science
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• v.48 no.2
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• pp.124-134
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• 2018

Purpose: Clinicians must examine tooth wear to make a proper diagnosis. However, qualitative methosds of measuring tooth wear have many disadvantages. Therefore, this study aimed to develop and evaluate quantitative parameters using the cusp area and volume of virtual dental models. Methods: The subjects of this study were the same virtual models that were used in our former study. The same age group classification and new tooth wear index (NTWI) scoring system were also reused. A virtual occlusal plane was generated with the highest cusp points and lowered vertically from 0.2 to 0.8 mm to create offset planes. The area and volume of each cusp was then measured and added together. In addition to the former analysis, the differential features of each cusp were analyzed. Results: The scores of the new parameters differentiated the age and NTWI groups better than those analyzed in the former study. The Spearman ${\rho}$ coefficients between the total area and the area of each cusp also showed higher scores at the levels of 0.6 mm (0.6A) and 0.8A. The mesiolingual cusp (MLC) showed a statistically significant difference (P<0.01) from the other cusps in the paired t-test. Additionally, the MLC exhibited the highest percentage of change at 0.6A in some age and NTWI groups. Regarding the age groups, the MLC showed the highest score in groups 1 and 2. For the NTWI groups, the MLC was not significantly different in groups 3 and 4. These results support the proposal that the lingual cusp exhibits rapid wear because it serves as a functional cusp. Conclusions: Although this study has limitations due to its cross-sectional nature, it suggests better quantitative parameters and analytical tools for the characteristics of cusp wear.

• The Journal of Advanced Prosthodontics
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• v.9 no.5
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• pp.381-386
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• 2017

PURPOSE. To integrate extra-oral facial scanning information with CAD/CAM complete dentures to immediately rehabilitate terminal dentition. MATERIALS AND METHODS. Ten patients with terminal dentition scheduled for total extraction and immediate denture placement were recruited for this study. The patients were submitted to a facial scanning procedure using the in-office PritiMirror scanner with bite registration records in-situ. Definitive stone cast models and bite records were subsequently submitted to a lab scanning procedure using the lab scanner (iSeries DWOS; Dental Wings). The scanned models were used to create a virtual teeth setup of a complete denture. Using the intra-oral bite records as a reference, the virtual setup was incorporated in the facial scan thereby facilitating a virtual clinical evaluation (teeth try-in) phase. After applying necessary adjustments, the virtual setup was submitted to a CAM procedure where a 5-axis industrial milling machine (M7 CNC; Darton AG General) was used to fabricate a full-milled PMMA immediate provisional prosthesis. RESULTS. Total extractions were performed, the dentures were immediately inserted, and subjective clinical fit was evaluated. The immediate provisional prostheses were inserted and clinical fit, occlusion/articulation, and esthetics were subjectively assessed; the results were deemed satisfactory. All provisional prostheses remained three months in function with no notable technical complications. CONCLUSION. Ten patients with terminal dentition were treated using a complete digital approach to fabricate complete dentures using CAD/CAM technology. The proposed technique has the potential to accelerate the rehabilitation procedure starting from immediate denture to final implant-supported prosthesis leading to more predictable functional and aesthetics outcomes.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.3
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• pp.277-290
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• 2012

Dental implants are universal restorative method on edentulous site in oral cavity and generally recognized by patients as well as clinicians. Rapid bone resorption of labial portion of maxillary anterior area is performed due to dental trauma, chronic periodontitis, and so on. Accordingly, Implants on maxillary anterior alveolar ridge with narrow labiopalatal width would lead to bony defects of dehiscence or fenestration. In this case, guided bone regeneration procedure is used to augment maxillary anterior alveolar ridge. It can have mechanical and biological advantages to mix tissue adhesive with bone graft materials in guided bone regeneration procedure. In these cases, when the dehiscence or fenestration defects was occurred by dental implants on maxillary anterior alveolar ridge with narrow labiopalatal width, guided bone regeneration procedures were performed with various combination of particle bone graft materials(allograft, xenograft, and alloplast) mixed with fibrin glue, excepting autogerous bone. We reported that all of 4 cases showed favorable alveolar ridge augmentations.

• Journal of Periodontal and Implant Science
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• v.34 no.1
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• pp.19-28
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• 2004

Tooth is the most important element in esthetic consideration on facial area. Tooth alignment which is in harmony with gingiva, lips, and face is also key element. The purpose of this study was to give a clinical discipline for restoration of gingival contour, which contains a ratio of maxillary 6 anterior teeth, research for gingival contour etc., in case of rehabilitation of maxillary anterior teeth. 300 Dankook university dental school students ,who is their twenties and free from periodontitis, participate in this study. The result was from each 70 males and females who had normal occlusion and tooth alignment. Length, width and length/width ratio of maxillary 6 anterior teeth were 0.74-0.81 in male, 0.81-0.84 in female. There was significant difference between male and female. The most deepest position of gingiva in maxillary central incisor and canine was located in distal part of teeth and maxillary lateral incisor was middle portion. In maxillary central incisors, gingival line of the most deepest point appeared significant difference between male and female (p<0.01) whereas there was no difference in lateral incisors and canines. Distance between interdental papilla apex and the most deepest portion appeared significant difference between male and female. Distance of the deepest position of gingiva is statistically significant except maxillary central incisors and lateral incisors. Standard deviation and mean of the width of labio-lingual were measured in cervical area and there was a significant difference both male and female.(p<0.01) From this result, we could get the mean of maxillary anterior gingival line and these results have great value in clinical guidance in studying maxillary anterior teeth.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.3
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• pp.252-257
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• 2014

It is important to produce a provisional restoration reflecting the patient's jaw relation, occlusal plane, lip support, shape of teeth, and occlusion type for fully edentulous patients before making a definite prosthesis. The patient introduced in this study showed bad prognosis of remained tooth after severe periodontal diseases. Therefore, remaining teeth were extracted and replaced with dental implants. Provisional restorations were fabricated and the the patient's vertical and horizontal jaw relationship, occlusal plane, amount of overjet and overbite, size of teeth, and length of anterior tooth were recorded. Provisional restorations were scanned and CAD/CAM techniques were used to fabricate a monolithic zirconia bridge, which contour is identical with the provisional restorations. The patient was satisfied with the treatment results on functional, esthetic aspects and the prosthesis retained stable during the four-month clinical observation period.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.36 no.4
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• pp.161-167
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• 2014

Purpose: The reconstruction of mandibular defects poses many difficulties due to the unique, complex shape of the mandible and the temporomandibular joints. With development of microvascular anastomosis, free tissue transplantation techniques, such as deep circumflex iliac artery (DCIA) flap and fibular free flap (FFF), were developed. The DCIA offers good quality and quantity of bone tissue for mandibular segmental defect and implant for dental rehabilitation. Virtual surgical planning (VSP) and stereolithography-guided osteotomy are currently successfully applied in three-dimensional mandibular reconstruction, but most use FFF. There are only a few articles on reconstruction with the DCIA that assess the postoperative results. Methods: Three patients admitted during a five month period (April of 2013 to August of 2013) underwent resection of mandible and DCIA musculo-osseous reconstruction using a VSP and stereolithographic modeling and assessment of outcomes included technical accuracy, esthetic contour, and functional outcomes. Results: This technique yielded iliac bone segment with excellent apposition and duplication of the preoperative plan. Flap survival was 100 percent and all patients maintained preoperative occlusion and contour. Conclusion: Based on our experience, we offer considerations and logically consistent protocols by classification of mandibular defects, and demonstrate the benefits in VSP and stereolithographic modeling of mandibular reconstructive surgery with DCIA flap.

• The korean journal of orthodontics
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• v.50 no.4
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• pp.268-277
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• 2020

This case report demonstrates two different uprighting mechanics separately applied to mesially tipped mandibular first and second molars. The biomechanical considerations for application of these mechanisms are also discussed. For repositioning of the first molar, which was severely tipped and deeply impacted, a novel cantilever mechanics was used. The molar tube was bonded in the buccolingual direction to facilitate insertion of a cantilever from the buccal side. By twisting the distal end of the cantilever, sufficient uprighting moment was generated. The mesial end of the cantilever was hooked over the miniscrew placed between the canine and first premolar, which could prevent exertion of an intrusive force to the anterior portion of the dentition as a side effect. For repositioning of the second molar, an uprighting mechanics using a compression force with two step bends incorporated into a nickel-titanium archwire was employed. This generated an uprighting moment as well as a distal force acting on the tipped second molar to regain the lost space for the first molar and bring it into its normal position. This epoch-making uprighting mechanics could also minimize the extrusion of the molar, thereby preventing occlusal interference by increasing interocclusal clearance between the inferiorly placed two step bends and the antagonist tooth. Consequently, the two step bends could help prevent occlusal interference. After 2 years and 11 months of active treatment, a desirable Class I occlusion was successfully achieved without permanent tooth extraction.