• The Journal of the Korean dental association
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• v.43 no.3 s.430
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• pp.218-224
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• 2005

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.1
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• pp.144-155
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• 1995

It is well known that implants showing no clinical mobility are successfully osseointegrated and have good prognosis. When implants are under load, their mobility begins to increase. It is of necessity to substantiate whether excessive load is on or premature occlusal force is acting prior to desirable osseointegration. Using Periotest unit, we could measure the pattern of mobility change. Consequently, osseointegrated treatment has come to success by intercepting progressive mobility and doing perceptive treatment according to the result of Periotest Value(PTV). In this study, we took records of intangible mobility of 70 osseointegrated implants. And we also measured the mobility of periodontally sound natural teeth as a standard from 30 dental personnel. Conclusions were summarized as followings ; 1. Lower lateral incisor has the highest PTV, whereas lower canine, upper canine, lower premolars and lower 1st molar have the lowest PTV in natural dentition. 2. There are little significant statistical difference of PTV between men and women in both(natural and implant) dentition. 3. In general, lower natural teeth show lower PTV than upper counterpart. 4. Mandibular implants have lower PTV than those of maxillary implants. 5. All of the successfully osseointegrated implants have lower PTV than those of periodontally healthy teeth.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.2
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• pp.203-244
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• 1998

The human mandible is always under the condition of loading by the various forces extorted by the attached muscles. The loading is an important condition of the stomatognathic system. This condition is composed of the direction and amount of forces of the masticatory muscles, which are controlled by the neuromuscular system, and always influenced by the movement of both opening and closing. Mandible is a strong foundation for the teeth or various prostheses, nevetheless it is a elastic body which accompanies deformation by the external forces on it. The elastic properties of the mandible is influenced by the various procedures such as conventional restorative treatments, osseointegrated implant treatments, reconstructive surgical procedures and so forth. Among the treatments the osseointegrated implant has no periodontal ligaments, which exist around the natural teeth to allow physiologic mobility in the alveolar socket. And so around the osseointegrated implant, there is almost no damping effect during the transmission of occlusal stress and displacements. If the osseointegrated implants are connected by the superstructure for the stabilization and effective distribution of occlusal stresses, the elastic properties of mandible is restricted according to the extent of 'splinting' by the superstructure and implants. To investigate the change of elastic behaviour of the mandible which has osseointegrated implant prosthesis of various numbers of implant installment and span of superstructre, a three dimensional finite element model was developed and analyzed with conditions mentioned above. The conclusions are as follows : 1. The displacements are primarily developed at the area of muscle attachment and distributed all around the mandible according to the various properties of bone. 2. The segmentation in the superstructure has few influence on the distribution of stress and displacement. 3. In the load case of ICP, the concentration of tensional stress was observed at the anterior portion of the ramus($9.22E+6N/m^2$) and at the lingual portion of the symphysis menti($8.36E+6N/m^2$). 4. In the load case of INC, the concentration of tensional stress was observed at the anterior portion of the ramus($9.90E+6N/m^2$) and the concentration of tensional stress was observed at the lingual portion of the symphysis menti($2.38E+6N/m^2$)). 5. In the load case of UTCP, the relatively high concentration of tensional stress($3.66E+7N/m^2$) was observed at the internal surface of the condylar neck.

• The Journal of the Korean dental association
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• v.54 no.4
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• pp.258-273
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• 2016

In spite of appropriate treatment of peri-implantitis, the peri-implant bone loss was keep going, the clinician should remove the osseointegrated implant. the conventional methods are like a extraction of natural teeth, and use of trephine drills. In these days, many exclusive instruments are invented by implant companies. these instruments can make easy, least invasive, less traumatic removal of osseointegrated implants. In generally peri-implant bone loss progress steadily less sign and symptoms that the patient do not want to remove their implants. However, the failure of dental implant is big burden to clinicians and also patients. In the dental implant treatment, there is no 'failure' but only is 'replacement' or 'change'.

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.2
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• pp.147-160
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• 1991

The purpose of this study was to examine, by the method of finite element analysis, how implant geometry with or without connection between natural tooth and osseointegrated abutments affected the stress distribution in surrounding bone and osseointegrated prosthesis. The mandibular first and second molars were removed and the two osseointegrated implants were placed in the first and second molar sites. Stress analysis induced by prostheses with connection(Model A)or without connection(Model B) between natural tooth(second bicuspid) and two osseointegrated abutments(first molar and second molar) was performed under vertical point load(Load P1) or distributed point load(Load P2). The results were as follows; 1. Under vertical point load, mesial tilting was shown in both Model A and Model B and inferior displacement of Model A was greater than that of Model B in the second bicuspid. 2. Under vortical point load, the first and second molars showed mesial tilting in both Model A and Model B, and inferior displacement of them was similar in Model A and Model B and was less than that of the second bicuspid. 3. Under distributed point load, mesial displacement was shown in Model A and Model B and inferior displacement of Model A was less than that of Model B in the second bicuspid. 4. Under distributed point load, mesial tilting was shown and inferior displacement of Model A was similar to that of Model B in the first and second molars. 5. In Model A under vertical point load, high stress was concentrated in the corneal portion of first molar and distributed throughout the second molar and the second bicuspid, and the stress distribution of the second molar was greater than that of the second bicuspid. 6. In Model B under vertical point load, high stress was concentrated in the coronal and mesio-cervical portion of the first molar. 7. In Model A under distributed point load, high stress was concentrated in the mesio-cervical portion of the first molar and evenly distributed throughout the second molar and the second bicuspid. 8. In Model B under distributed point load, high stress was concentrated in the disto-cervical portion of the second bicuspid and evenly distributed throughout the first and second molars.

• 대한치과보철학회:학술대회논문집
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• 1999.11a
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• pp.138-138
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• 1999

• The Journal of Korean Academy of Prosthodontics
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• v.34 no.1
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• pp.70-84
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• 1996

This paper reports marginal bone loss around osseointegrated implants after loading in partially edentulous patients in dental hospital, Yonsei University. Two types of implants($Br{\aa}nemark^{TM},\;IMZ^{TM}$) were used. Through the digital measurement on periapical radiograph around 37 implants in human subjects, marginal bone loss was observed for 24 months after delivery of prostheses. The results were as follows; 1. According to experimental periods marginal bone loss in total implants was 1.775 mm at 12 months, 1.921 mm at 24 months after delivery of prostheses(p<0.05). 2. Marginal bone loss in the $Br{\aa}nemark$ implants was 1.831 mm at 12 months, 1.833 mm at 24 months after delivery of prostheses(p<0.05). 3. Marginal bone loss in the IMZ implants was 1.578 mm at 12 months, 2.907 mm at 23 months after delivery of prostheses(p<0.05). 4. During the first year after loading, the IMZ implants showed less marginal bone loss than the $Br{\aa}nemark$ implants but, during the next the $Br{\aa}nemark$ implants showed less than the IMZ implants(p>0.05). These results indicate that marginal bone loss around osseointegrated implants occurs within the first 12 months after delivery of prostheses and stabilizes thereafter, so it is necessary to be careful of using dental implants for the first year after delivery of prostheses.

• The Journal of Korean Academy of Prosthodontics
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• v.31 no.3
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• pp.411-422
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• 1993

Osseointegrated dental implants are now an accepted part of the prosthetic treatment of fully and partially edentulous patients. Clinical studies have shown that osseointegrated dental implants may successfully be used as abutments for prosthetic rehabilitations, and that the supporting tissue can be kept in a stable and healthy clinical state for prolonged periods of time. The purpose of this study was to look for differences in the distribution in the bacterial morphotypes around natural teeth and osseointegrated dental implants. The subgingival plaque around natural teeth and implants was analysed by means of differential phase-contrast microscopy. In addition, clinical indices used to analyse natural teeth condition were used to compare the condition of natural teeth and implants. The results were as follows : 1. In implants of partially edentulous patients, the plaque index, sulcus bleeding index(P<0.05), pocket depth(P<0.01) were greater than natural teeth. 2. Gingival crevicular fluid volume was not significantly different between natural teeth and implants. 3. In implants of fully edentulous patients, the plaque index was greater than natural teeth(P<0.01) and implants of partially edentulous patients(P<0.05), but sulcus bleeding index was not significantly different. 4. In partially edentulous patient, coccoid cell proportion was greater in implants than natural teeth (P<0.05). 5. In implants of fully edentulous patients, coccid cell proportion was even greater than implants of partially edentulous patients(P<0.05) and natural teeth(P<0.01). 6. Among three groups, the proportions of non-motile rods, motile rods, spirochetes and others were not significantly different. 7. The proportion of motile bacteria was not significantly different among three group.

• The Journal of Korean Academy of Prosthodontics
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• v.31 no.1
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• pp.151-162
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• 1993

The author installed $3.75mm\times10mm$ $Br{\aa}nrmark$ osseointegrated implants and $3.5mm\times8mm$ I.T.I. hollow screw implants(Benefit) as a free standing abutment to replace lower left and right molars of 44-year-old female patient. Form the foregoing procedure, the author obtained the following results. 1. Free-standing $Br{\aa}nrmark$ and I.T.I. Hollow screw implants(Benefit) could be used to replace molars effectively without reduction of adjacent natural teeth, 2. Rotation of occlusal gold screw of $Br{\aa}nrmark$ implants was observed under occlusal force. 3. Adjustment of height of I.T.I. abutments was necessary in the mandibular second molar because of the limited occlusal clearance. 4. Form the oral examination, patient comments, panoramic and periapical radiographs, there were no pain, gingival imflammation and mobility, but slight reduction of alveolar bone level was shown around both implant systems. 5. Patient comments were comfortable on both systems. but the patient complained about economic problem of $Br{\aa}nrmark$ system and long treatment treatment time of both systems.

• The Journal of Korean Academy of Prosthodontics
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• v.35 no.1
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• pp.95-102
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• 1997

Ameloblastoma is the most agrressive ofht odontogenic tumors and it arises from the dental lamina or the derivatives of lamina. Ameloblastoma is a benign but locally invasive neoplasm consisting of proliferating odontogenic epithelium lying in a fibrous stroma. Usually the ameloblastomas are diagnosed in the forth and fifth decardes. Over 80% of them occur in the mandible, the remainder in the maxilla. The preferred treatment for ameloblastoma is radical excision, conserving(when possible. the inferior border of the mandible. The functional and esthetic rehabilitation of the partially edentulous patient may prevent the remaining structures from supporting conventional prosthetic treatment. Patients with long edentulous spans, malpositioned teeth, residual ridges defects and high muscle attachments may be offered an osseointegrated fixed prosthesis. Osseointegrated dental implants provide a viable alternative of tooth replacement. This is a case report of 16 year old female with ameloblastoma. We treated patient with radical excision, conserving the inferior border of the mandible and allogenous bone graft. The defected residual ridge area was reconstructed implants(Steri-Oss Implant System). the result was satisfactory.