• The Journal of the Korean dental association
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• v.48 no.8
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• pp.615-620
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• 2010

Purpose: The short dental implant is considered as possible solution in the alveolar bone height deficient cases. The aim of this study was to evaluate clinical availability of short implants by measuring the marginal bone loss of short length implants and comparing with that of conventional length implants. Materials and Methods: The groups were composed of patients who had received at least one implant. The samples of this study were selected from patients who with functional loading after prosthetic treatment for 1 year follow up period. The implants with a length of 5.7 mm and 6mm were considered short. (Bicon Dental implants, USA). The experiment group was composed of $4.5{\times}6mm$, $5{\times}6mm$, $6{\times}5.7mm$ implants (total 18 implants were placed in 14 patients, 8 on maxilla, 10 on mandible). The control group was composed of $4.5{\times}8mm$, $5{\times}8mm$, $4.5{\times}11mm$, $5{\times}11mm$. All implants were selected only by implants placed on molar area. We evaluated marginal bone loss in radiographic images at baseline (implant loading) and 3, 6, 12 months after loading. Additionally, crown-to-implant ratio was evaluated, and marginal bone loss according to crown-to-implant ratio after functional loading was analyzed. Results: The short implant group had a mean marginal bone level of $-0.52{\pm}0.69mm$; the 8mm group, $-0.22{\pm}0.82mm$; and the II mm group, $-0.10{\pm}1.09mm$ after I year of functional loading. But significant differences were not detected between three groups at every follow-up period. Crown-to-implant ratio in short implant group was $1.55{\pm}0.23$; 8mm group was $1.15{\pm}0.18$; and 11mm group was $0.92{\pm}0.15$. Additionally, significant differences between three groups were founded. (P<.0001) The greatest marginal bone loss after 1 year follow-up was founded at crown-to-implant ratio 1~1.49 range in short implant. Conclusion: The marginal bone loss of short implants was comparable to that of long implants. So, the short implants can be a clinically acceptable option.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.2
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• pp.128-134
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• 2010

Purpose: The aim of this study was to evaluate the changes in bone density and reduction of time consumed for osteogenesis by $PostPlant^{TM}$ Calcium and to find out efficacy of $PostPlant^{TM}$ Calcium by comparing the group prescribed with $PostPlant^{TM}$ Calcium with the group without $PostPlant^{TM}$ Calcium prescription. Material and methods: The experimental group of 18 patients with 25 dental implant placement and the control group of 7 patients with 9 dental implant placement were randomly selected from the patients who visited prosthetic department of Dankook University Dental Hospital since July, 2006 (IRB Number ; 20060710). The experimental group was instructed to take $PostPlant^{TM}$ Calcium for 6 months after the implant surgery while the control group was instructed not to. Both experimental and control group were assigned for measurement using $Osstell^{TM}$ Mentor and $Periotest^{(R)}$ and radiographic examination was performed using specifically manufactured Aluminum Step Wedge. The results were compared and analyzed. Results: 1. According to the $Osstell^{TM}$ Mentor measurement, both the experimental and control group showed increase in values as time elapses and the experimental group showed significantly higher rate of increase (P < .05). 2. According to the $Periotest^{(R)}$ measurement, both the experimental and control group showed decrease in values as time elapses. In addition, greater decrease can be seen in the experimental group but no statistical significance was found. 3. By examining the radiographic images, both the experimental and control group showed tendency of increase in bone density. In addition, greater increase can be seen in the experimental group but no statistical significance was found. Conclusion: Clinically, taking $PostPlant^{TM}$ Calcium medicine for a long period of time after implant placement is expected for a better prognosis.

• Journal of Dental Rehabilitation and Applied Science
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• v.35 no.4
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• pp.214-219
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• 2019

Purpose: The aim of this study was to evaluate the correlation between inter-condylar width and inter-maxillary first molar width to present the criteria for prosthetic reconstruction of dental arch width in maxillary and mandibular fully edentulous patients. Materials and Methods: 120 Koreans (60 males and 60 females) who underwent the cone beam computerized tomography (Cone-beam CT) were selected. The Cone-beam CT images were analysed using Invivo 5.1. After reorientation of axis, inter-maxillary first molar width was measured by clicking both mesio-buccal cusp tip of maxillary first molar. And inter-condylar width was measured by clicking both middle points of condyles. The collected data were analysed with SPSS Version 20.0 and statistical significance of the correlation between inter-condylar width and inter-maxillary first molar width was verified by Pearson's correlation analysis. Results: The mean inter-condylar width of Korean was 105.9 mm, and that of male (108.3 mm) was statistically significantly wider than the female (103.4 mm). The inter-maxillary first molar width of Korean was 57.1 mm, and that of male (57.9 mm) was statistically significantly wider than the female (56.2 mm). Pearson's correlation analysis between inter-condylar width and inter-maxillary first molar width showed a Pearson correlation coefficient of 0.614 and statistically significantly positive correlation. Conclusion: Intercondylar width and inter-maxillary first molar width showed positive correlation and the average ratio of inter-condylar with and inter-maxillary first molar width was 1:0.54. Based on the results of this limited study, inter-condylar width can be used as a guide for setting up dental arch width in fully edentulous patient.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.1
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• pp.53-64
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• 2008

Statement of problem: Peri-implant marginal bone loss is an important factor that affects the success of implants in esthetics and function. Various efforts have been made to reduce this bone loss by improving implant design and surface texture. Previous studies have shown that early marginal bone loss is affected by implant neck designs. Purpose: The purpose of this study was to examine the influence of laser microtexturing of implant collar on peri-implant marginal bone loss. Materials and methods: Radiographical marginal bone loss was examined in patients treated with implant-supported fixed partial dentures. Marginal bone level was examined with 101 implant fixtures installed in 53 patients at three periods(at the time of implantation, prosthetic treatment and 6-month after loading). Four types of implants were examined. The differences of bone loss between implants(ITI standard) with enough biologic width and implants(ITI esthetic plus, Silhouette IC, Silhouette IC Laser-$Lok^{TM}$) with insufficient biologic width have been compared. Resorption angles were examined at the time of prosthetic delivery and 6-month after loading. Results and Conclusion: Within the limitation of this study, the following results were drawn. 1. The marginal bone loss of ITI standard and Silhouette IC Laser-$Lok^{TM}$ was less than that of ITI esthetic plus and Silhouette IC(P<0.05). The marginal bone loss between ITI standard and Silhouette IC Laser-$Lok^{TM}$ had no significant statistical difference(P>0.05). There was no significant statistical difference between marginal bone loss of ITI esthetic plus and Silhouette IC(P>0.05). 2. There was no significant difference in marginal bone loss between maxilla and mandible(P>0.05). 3. There was no significant difference in resorption angle among four types of implants(P>0.05). The marginal bone of implants with supracrestal collar design of less than that of biologic width had resorbed more than those with sufficient collar length. The roughness and laser microtexturing of implant neck seem to affect these results. If an implant with collar length of biologic width, exposure of fixture is a possible complication especially in the anterior regions of dentition that demand high esthetics. Short smooth neck implant are often recommended in these areas which may lack the distance between microgap and the marginal bone level. In these cases, the preservation of marginal bone must be put into consideration. From the result of this study, it may be concluded that laser microtexturing of implant neck is helpful in the preservation of marginal bone.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.1
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• pp.36-43
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• 2012

Purpose: To analyze the stress distribution of the implant and its supporting structures through 3D finite elements analysis for implants with different hexagon heights and to make the assessment of the mechanical stability and the effect of the elements. Materials and methods: Infinite elements modeling with CAD data was designed. The modeling was done as follows; an external connection type ${\phi}4.0mm{\times}11.5mm$ Osstem$^{(R)}$ USII (Osstem Co., Pusan, Korea) implant system was used, the implant was planted in the mandibular first molar region with appropriate prosthetic restoration, the hexagon (implant fixture's external connection) height of 0.0, 0.7, 1.2, and 1.5 mm were applied. ABAQUS 6.4 (ABAQUS, Inc., Providence, USA) was used to calculate the stress value. The force distribution via color distribution on each experimental group's implant fixture and titanium screw was studied based on the equivalent stress (von Mises stress). The maximum stress level of each element (crown, implant screw, implant fixture, cortical bone and cancellous bone) was compared. Results: The hexagonal height of the implant with external connection had an influence on the stress distribution of the fixture, screw and upper prosthesis and the surrounding supporting bone. As the hexagon height increased, the stress was well distributed and there was a decrease in the maximum stress value. If the height of the hexagon reached over 1.2mm, there was no significant influence on the stress distribution. Conclusion: For implants with external connections, a hexagon is vital for stress distribution. As the height of the hexagon increased, the more effective stress distribution was observed.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.4
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• pp.252-259
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• 2017

Purpose: The purpose of this study was to compare and analyze the wear of a prosthesis for 6 months after restoration with implant-supported fixed dental prosthesis made of either zirconia or gold. Materials and Methods: This study was conducted on patients requiring implant-supported fixed dental prostheses on first or second molar from January, 2015 to January, 2016. A total of 47 prostheses and antagonists were examined. Occlusal surface was recorded by impression of each prosthesis and antagonist 1 week and 6 months after prosthesis delivery. The digital files were created by impression scan. Occlusal shapes of 1 week and 6 months were compared and wear of prostheses and antagonists was analyzed. The Mann-Whitney test was used to analyzed the result data underwent normality test using SPSS (Version 23.0, IBM Corporation) Results: Mann-Whitney test revealed that there was no statistically significant difference in the median amount of mean vertical wear for 6 months in zirconia ($50.84{\mu}m$) and gold ($42.84{\mu}m$) prostheses (P > 0.05). When the opposing teeth were natural, the median amount of mean vertical wear of zirconia and gold prostheses was $47.72{\mu}m$ and $41.97{\mu}m$, respectively, and the median amount of mean vertical wear of enamel was $47.26{\mu}m$ and $44.59{\mu}m$, respectively. Statistical analysis showed no significant difference (P > 0.05). Conclusion: Despite the short study period and the small number of experimental groups, zirconia and gold showed no significant difference in wear during the first 6 months. Opposing natural enamel also showed no significant difference in the wear.

• Journal of Oral Medicine and Pain
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• v.33 no.1
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• pp.15-26
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• 2008

Purpose : To investigate the actual conditions of diagnosis and treatment of oral medicine inpatient with systemic disease. Methods : A total of 110 subjects, inpatient due to systemic disease for diagnosis and treatment of oral disease was requested to answer the medical history and dental treatment record. Results : Systemic disease is composed of Non-insulin-dependent diabetes mellitus 26%, Cerebral infarction 25.2%, Intracerebral hemorrhage, Polyarthrosis, Coxarthrosis 4.7%, Nerve root and plexus disorders, Hypertensive heart and renal diseases, Ankylosing spondylitis 2.4%. Chief complain of oral disease is composed of toothache 28.6%, routine check 23%, tooth mobility 8.7%, hypersensitivity 7.1%, periodontal bleeding 6.4%. Oral disease is composed of Gingivitis and periodontal diseases 28.9%, Dental caries 17.1%, Diseases of pulp and periapical tissues 15.1%, Diseases of salivary glands 10.5%, Other diseases of hard tissues of teeth 8.6%, Within Normal Limit 5.3%. Treatment of oral disease is composed of periodontal treatment 17.95%, rejection of treatment 16.67%, medication for halitosis & dry mouth 13.46%, extraction 12.18%, prosthetic treatment 8.97%. Chief complain in oral medicine is composed of oral soft tissue problem 6.4%, craniomandibular disorders 5.6%, halitosis 4%, total 16%. Conclusion : These findings indicate that inpatient due to the systemic disease is significantly correlated to the oral disease. The patients of oral disease interrelationship between inpatient and outpatient of systemic disease should be validated by future research.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.4
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• pp.365-375
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• 2009

Statement of problems: Stress analysis on implant components of the combined screw- and cement-retained implant prosthesis has not investigated yet. Purpose: The purpose of this study was to assess the load distribution characteristics of implant prostheses with the different prosthodontic retention types, such as cement-type, screw-type and combined type by using 3-dimensional finite element analysis. Material and methods: A 3-dimensional finite element model was created in which two SS II implants (Osstem Co. Ltd.) were placed in the areas of the first premolar and the first molar in the mandible, and three-unit fixed partial dentures with four different retention types were fabricated on the two SS II implants. Model 1 was a cement-retained implant restoration made on two cement-retained type abutments (Comocta abutment; Osstem Co. Ltd.), and Model 2 was a screw-retained implant restoration made on the screw-retained type abutments (Octa abutment; Osstem Co. Ltd.). Model 3 was a combined type implant restoration made on the cement-retained type abutment (Comocta abutment) for the first molar and the screw-retained type abutment (Octa abutment) for the first premolar. Lastly, Model 4 was a combined type implant restoration made on the screw-retained type abutment (Octa abutment) for the first molar and the cement-retained type abutment (Comocta abutment) for the first premolar. Average masticatory force was applied on the central fossa in a vertical direction, and on the buccal cusp in a vertical and oblique direction for each model. Von-Mises stress patterns on alveolar bone, implant body, abutment, abutment screw, and prosthetic screw around implant prostheses were evaluated through 3-dimensional finite element analysis. Results: Model 2 showed the lowest von Mises stress. In all models, the von Mises stress distribution of cortical bone, cancellous bone and implant body showed the similar pattern. Regardless of loading conditions and type of abutment system, the stress of bone was concentrated on the cortical bone. The von-Mises stress on abutment, abutment screw, and prosthetic screw showed the lower values for the screw-retained type abutment than for the cement-retained type abutment regardless of the model type. There was little reciprocal effect of the abutment system between the molar and the premolar position. For all models, buccal cusp oblique loading caused the largest stress, followed by buccal cusp vertical loading and center vertical loading. Conclusion: Within the limitation of the FEA study, the combined type implant prosthesis did not demonstrate more stress around implant components than the cement type implant prosthesis. Under the assumption of ideal passive fit, the screw-type implant prosthesis showed the east stress around implant components.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.1
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• pp.57-65
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• 2008

Purpose: Misfit of implant components was very important in terms of prosthodontics. they has been linked to prosthetic complications such as screw loosening and fracture. Although there are many results about rotational freedom or machining tolerance between fixture and abutments, the data about domestic implant systems are lacking. The aim of this in vitro study was to evaluate the rotational freedom of domestic external and internal connection implant systems between their fixtures/anlaogs and abutments comparing imported systems. Materials and Methods: Rotational freedom between abutments and fixtures/analogs was investigated by using digitalized rotational angle measuring device. (1) 1 domestic external connection system(Neobiotec) and 2 imported external connection systems(Nobel Biocare, Anthorgyr), (2) 1 domestic internal connection system(Dentium) and 4 imported external connection systems(Nobel Biocare, Anthorgyr, Straumann, Frident Dentsply), and (3) 1 domestic zirconia external connection abutment(ZirAce) were evaluated. Each group has 3 samples. Mean values for each group were analyzed. Results: The differences relative to rotational freedom between domestic and imported implant systems were observed but domestic external connection implant system showed about 2.67 degrees(in case of fixture) and internal connection system showed about 4.3 degrees(in case of fixture). Domestic zirconia abutment showed less than 3 degrees of rotational freedom in a situation where the abutment was connected to an implant fixture egardless of domestic or imported systems. Conclusion: Newly developed digitalized rotational angle measuring device has high measuring resolution. The rotational freedom of domestic implant systems were similar to imported implant systems.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.5
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• pp.428-433
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• 2004

Sinus floor augmentation has been proven an effective treatment procedure to increase bone volume in the posterior edentulous maxilla. Autogenous bone considered to be the best material for reconstructive bone surgery and has been successfully used as a graft material to augment posterior maxilla. However, the collection of autogenous bone required extra risks for morbidity and complaints. So, various bone graft materials included ${\beta}$-tricalcium phosphate(${\beta}$-TCP) has been introduced for replacing the autogenous bone. The objective of this clinical study was to determine the predictability of endosseous implant placed in a maxillary sinus with ${\beta}$-TCP grafting. We performed sinus elevation with ${\beta}$-TCP to install the implant in the 10 maxillary cases. The prosthetic procedure was performed 6-9 months after. The implant-prosthetics was checked about 1 year. We checked the implant and measured the maximum bite force to evaluate the function of the implant. There was not observed the specific problem and complication in dental implant and maxillary sinus in the grafted materials. The maximum bite force was 558N in case of natural tooth, 365N in implant without grafting, 318N in implant with ${\beta}$-TCP grafting. There was no significant difference between with and without sinus grafting on maximum bite force(p>0.05). As though the long term check-up is needed, the grafting of ${\beta}$-TCP as a osteoconductive materials can expand the volume and induce dense new bone formation in maxillary sinus. So, this short-term results support that ${\beta}$-TCP can be a suitable material for sinus augmentation.