• Restorative Dentistry and Endodontics
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• v.22 no.2
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• pp.546-559
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• 1997

The purposes of this study were to evaluate the efficiency of cavity preparation and to determine the incidence of tooth crack when root-end retrograde cavity preparation was done with ultrasonics. 91 distobuccal root-ends of extracted human maxillary first molars were cut by 3 mm perpendicularly to the long axis of tooth using a slow speed diamond saw, retrocavities were prepared using a slow-speed no. 2 round bur as controls, and stainless steel ultrasonic tips of power settings of 1 through 10 as experimentals. Time consumed and the number of strokes used for the cavity preparation were measured and evaluated, and the incidence of tooth cracks was observed under a stereomicroscope. The results were as follows : For the retrograde cavity preparation, time and number of strokes used were decreased as the ultrasonic power setting increased (p<0.001). High power setting of ultrasonics induced significantly more tooth cracks than did the slow-speed bur or low- and medium power setting of ultrasonics (p<0.05). Teeth with previous crack induced significantly more tooth cracks than those without previous one when high power setting of ultrasonics were used for the retrograde cavity preparation (p<0.001). Teeth with initial apical canal size of no. 10 induced significantly more crack than did those with size of no. 15 when low power setting of ultrasonics were used for the retrograde cavity preparation (p<0.05).

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.5
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• pp.478-483
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• 2010

Bisphosphonates are synthetic analogue and have high affinity on bone remodeling site. Since they have a long half-reduction time, they accumulate at bone and act for a long time. They are widely used in osteo-porosis derived from imflammatory bowel disease or postmenopausal osteoporosis patient for bone mineral density improvement. In addition, they neutralize hypercalcemia owing to bone metastasis of malignancy. However, a jaw bone necrosis was recently reported in some patients who have taken bisphosphonates for a long time. It is called Bisphosphonate Related Osteonecrosis of Jaws (BRONJ). It can come spontaneous-ly, but more often after oral surgery including tooth extraction. In this case, a 80-year-old woman was treated with bisphosphonate (sodium alendronate) for 2 years to improve bone mineral density. She had her left lower second molar tooth extracted at local clinic. After extraction, she had inflammatory symptoms like a pain, a cheek swelling, and a discharge of pus. She was referred to our clinic for treatment. We treated meticulously from dressing to surgery. After following up about 1.5 years, the jaw lesion was successfully healed. So we report this case.

• Journal of Periodontal and Implant Science
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• v.39 no.4
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• pp.431-435
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• 2009

Purpose: The purpose of this study is to evaluate the long term clinical and radiographic outcome and stability after transplantation of third molar with complete root formation. Methods: The subjects were 31 teeth (male 17, female 14, aged 22-55, average 39.9 yr old) of 31 patients who visited the department of periodontics and passed more than two years after autotransplantation procedure and still under regular check up. Modified success criteria of Chamberlin and Goerig was applied to determine the success of autotransplantation. Results: Three out of 31 teeth failed and resulted 90.3% of success rate. When compared according to sex, 15 out of 17 teeth had succeeded in male, 13 out of 14 succeeded in female. When compared the success rate according to cause of extraction, tooth loss due to caries and root fracture had all succeeded but 3 out of 24 had failed in tooth loss due to periodontal disease. When compared according to donor teeth, 12 out of 14 maxillary third molars and 16 out of 17 mandibular third molars had succeeded. Conclusions: In long term evaluation over two years, if appropriate surgical procedure and proper case selection is made, autotransplantation of the third molar with complete root formation can be the alternative choice that substitutes prosthetic or implant treatment and it is a functionally acceptable procedure.

• The korean journal of orthodontics
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• v.49 no.1
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• pp.59-69
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• 2019

In this report, we describe a case involving a 34-year-old woman who showed good treatment outcomes with long-term stability after multidisciplinary treatment for unilateral cleft lip and palate (CLP), maxillary hypoplasia, severe maxillary arch constriction, severe occlusal collapse, and gingival recession. A comprehensive treatment approach was developed with maximum consideration of strong scar constriction and gingival recession; it included minimum maxillary arch expansion, maxillary advancement by distraction osteogenesis using an internal distraction device, and mandibular setback using sagittal split ramus osteotomy. Her post-treatment records demonstrated a balanced facial profile and occlusion with improved facial symmetry. The patient's profile was dramatically improved, with reduced upper lip retrusion and lower lip protrusion as a result of the maxillary advancement and mandibular setback, respectively. Although gingival recession showed a slight increase, tooth mobility was within the normal physiological range. No tooth hyperesthesia was observed after treatment. There was negligible osseous relapse, and the occlusion remained stable after 5 years of post-treatment retention. Our findings suggest that such multidisciplinary approaches for the treatment of CLP with gingival recession and occlusal collapse help in improving occlusion and facial esthetics without the need for prostheses such as dental implants or bridges; in addition, the results show long-term post-treatment stability.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.16 no.2
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• pp.7-18
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• 2007

There is now an increased demand for harmony between the peri-implant gingiva and adjacent dentition. In the event of a pending loss of a single tooth in the aesthetic zone with healthy periodontium, expectation for optimal gingival and prosthodontic aesthetics are often very high. Unfortunately, bone resorption is common following the removal of an anterior tooth, compromising the gingival tissue levels for the eventual implant restoration. Also, improper implant placement and inadequate osseous-gingival support potentially deleterious aesthetic result. The creation of an esthetic implant restoration with gingival architecture that harmonizes with the adjacent dentitionis formidable challenge. The predictability of the peri-implant esthetic outcome may ultimately be determined by the patient's own presenting anatomy rather than the clinician's ability to manage state-of-the-art procedures. To more accurately predict the peri-implant esthetic outcome before removing a failing tooth, a considering of diagnostic keys is essential. This presentation addresses the useful diagnostic keys that affect the predictability of peri-implant gingival aesthetics and the overcoming of the risk factors in anterior single-tooth replacement; it also describes a surgical and prosthodontic technique in achieving a long term successful esthetic outcome. Proper diagnosis and understanding of the biological and periodontal variables of failing dentition and their response to surgical and prosthodontic procedures are the essence of predictability. Using a smart protocol that alters the periodontium toward less risk and more favorable assessment of the diagnostic keys before implant placement will provide the most predictable esthetic outcome. Simple diagnostic keys suggested this presentation are useful method to evaluate the overcoming of the risk factors in anterior single implant restoration.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.435-438
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• 2003

The MS card data transfer system using blue-tooth protocol ran communicate the MS card data wirelessly and does not take an extra communication expense which is a weakness point of existing wireless communication system. This Blue-tooth system, which has excellent security and no extra communication expense, can efficiently communicate data of the place ,where can be solved with small scale wireless network, such as the theme-park or gasoline-station. Existing wireless communication system compose network using wireless-LAN protocol which has extra communication expense, or with RF protocol which has poor security. But this system suitable for LAN because it has not extra communication expense and it has excellent security cause frequency-hopping of Blue-tooth protocol. The MS card data transfer system using blue-tooth protocol has low power, high performance RISC processor and large scale 16-gray graphic LCD which is suitable for portable unit. The MS card data transfer system can efficiently control depot for a long time because it has low power, excellent security and no extra communication expense.

• The Journal of Advanced Prosthodontics
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• v.7 no.6
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• pp.423-430
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• 2015

PURPOSE. To evaluate the cumulative survival rate (CSR) and mechanical complications of single-tooth $Ankylos^{(R)}$ implants. MATERIALS AND METHODS. This was a retrospective clinical study that analyzed 450 single $Ankylos^{(R)}$ implants installed in 275 patients between December 2005 and December 2012. The main outcomes were survival results CSR and implant failure) and mechanical complications (screw loosening, fracture, and cumulative fracture rate [CFR]). The main outcomes were analyzed according to age, sex, implant length or diameter, bone graft, arch, and position. RESULTS. The 8-year CSR was 96.9%. Thirteen (2.9%) implants failed because of early osseointegration failure in 3, marginal bone loss in 6, and abutment fracture in 4. Screw loosening occurred in 10 implants (2.2%), and 10 abutment fractures occurred. All abutment fractures were located in the neck, and concurrent screw fractures were observed. The CSR and rate of screw loosening did not differ significantly according to factors. The CFR was higher in middle-aged patients (5.3% vs 0.0% in younger and older patients); for teeth in a molar position (5.8% vs 0.0% for premolar or 1.1% for anterior position); and for larger-diameter implants (4.5% for 4.5 mm and 6.7% for 5.5 mm diameter vs 0.5% for 3.5 mm diameter) (all P<.05). CONCLUSION. The $Ankylos^{(R)}$ implant is suitable for single-tooth restoration in Koreans. However, relatively frequent abutment fractures (2.2%) were observed and some fractures resulted in implant failures. Middle-aged patients, the molar position, and a large implant diameter were associated with a high incidence of abutment fracture.

• Restorative Dentistry and Endodontics
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• v.43 no.4
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• pp.48.1-48.13
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• 2018

Objectives: To analyze the influence of thickness and incisal extension of indirect veneers on the stress and strain generated in maxillary canine teeth. Materials and Methods: A 3-dimensional maxillary canine model was validated with an in vitro strain gauge and exported to computer-assisted engineering software. Materials were considered homogeneous, isotropic, and elastic. Each canine tooth was then subjected to a 0.3 and 0.8 mm reduction on the facial surface, in preparations with and without incisal covering, and restored with a lithium disilicate veneer. A 50 N load was applied at $45^{\circ}$ to the long axis of the tooth, on the incisal third of the palatal surface of the crown. Results: The results showed a mean of $218.16{\mu}strain$ of stress in the in vitro experiment, and $210.63{\mu}strain$ in finite element analysis (FEA). The stress concentration on prepared teeth was higher at the palatal root surface, with a mean value of 11.02 MPa and varying less than 3% between the preparation designs. The veneers concentrated higher stresses at the incisal third of the facial surface, with a mean of 3.88 MPa and a 40% increase in less-thick veneers. The incisal cover generated a new stress concentration area, with values over 48.18 MPa. Conclusions: The mathematical model for a maxillary canine tooth was validated using FEA. The thickness (0.3 or 0.8 mm) and the incisal covering showed no difference for the tooth structure. However, the incisal covering was harmful for the veneer, of which the greatest thickness was beneficial.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.50 no.3
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• pp.140-145
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• 2024

Objectives: The necessity of retrograde filling after apicoectomy is controversial in cases of non-inflammatory cysts as opposed to bacteria-related periapical abscesses. This study aims to investigate whether the presence or absence of retrograde filling during apicoectomy has differential long-term prognostic implications between inflammatory and non-inflammatory cysts. Materials and Methods: This retrospective study included patients who underwent tooth apicoectomy during jaw cyst enucleation between 2013 and 2022, and who underwent follow-up cone-beam computed tomography for at least 6 months. The prognosis of the tooth was evaluated during the follow-up period according to the cyst type, the presence or absence of retrograde filling, mandible or maxilla, and location. Results: A total of 147 teeth was included in this study. All the operated teeth underwent preoperative root canal treatment by an endodontic specialist. Apicoectomy was performed for 119 inflammatory cysts and 28 non-inflammatory cysts. Retrograde filling was performed on 22 teeth with inflammatory cysts and 3 teeth with non-inflammatory cysts. All teeth survived the 3.5-year follow-up (range, 1.0-9.1 years). However, 1 tooth with an inflammatory cyst developed complications 1 year after surgery that required re-endodontic treatment. Conclusion: The prognosis of a tooth treated by apicoectomy without retrograde filling during cyst enucleation is favorable, regardless of the cyst type.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.4
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• pp.397-403
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• 2012

The vitality of immature tooth could be lost by dental caries, trauma and fracture of malformed tooth. The vitality loss might lead to halt of the development of the root. The recommended endodontic treatment for a non-vital immature permanent tooth is apexification. Apexification is a method of inducing apical closure through the formation of mineralized tissue in the apical pulp region. Calcium hydroxide is the material of choice for apexification. Long-term exposure to calcium hydroxide may form the apical hard tissue, but weaken the dentin due to its alkaline nature and thus make the roots more susceptible to fracture. It is important to preserve any weakened tooth, so a permanent restoration is needed to reinforce teeth that are prone to fracture. The purpose of this case report was to describe the treatment for reinforcing immature teeth treated with long-term calcium hydroxide. In these cases, the apexes of teeth were sealed with MTA plugs and the root canals were restored with composite resin and fiber post.