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A COMPARATIVE STUDY ON THE FIT IN PROSTHESES USING PREMADE GOLD CYLINDER AND PLASTIC CYLINDER.

Seon Hee JUNG ; Jang Seon MA ; Chae Heon CHUNG

The Journal of Korean Academy of Prosthodontics.1999;37(6):825-834.

Recently, various implant cylinders were supplied, especially received gold cylinders, cast cylinders produced from premade gold and plastic cylinders and plastic cylinders. This study measured and compared precise fit produced when using conventional gold and plastic cylinders. The comparative fit of lapped and non-lapped castings made from plastic pattern was examined. The implant/abutment interface fit was evaluated by scanning electron microscopy(SEM) for each of four cylinders. The following results were obtained: 1. The case of plastic cylinder showed 9.67+/-1.50micrometer gap Steri-Oss fixture was connected. 2. The case oflapped casting made from plastic cylinder showed 3.01+/-2.81micrometer gap when Steri-Oss fixture was connected. 3. The case of gold/plastic cylinder showed 9.80+/-1.68micrometer gap when Steri-Oss fixture was connected. 4. The case of gold cylinder showed 5.47+/-2.43micrometer gap when Steri-Oss fixture was connected. 5. In case of each cylinder which was connected with Steri-Oss fixture, the size of gap was showed less in the order of the case of gold/plastic cylinder, the case of plastic cylinder, the case of gold cylinder and the case of lapped casting made from plastic cylinder. As results of this study, the use of premade gold cylinder offers an advantage over plastic patterns in precise fit. When plastic patterns are used, polishing of implant cylinder components should provide precise fit.
Plastics* ; Prostheses and Implants*

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PALATELESS COMPLETE DENTURE FOR RESTORING GOOD TASTES : A CASE REPORT.

Eon Hee SONG ; Rae gyoung KIM ; Hyun Jeong AHN ; Sook BYUN ; Byeong Gap CHOI

The Journal of Korean Academy of Prosthodontics.1999;37(6):819-824.

The Purpose of this article is to present a clinical case report for palateless complete denture. Despite the contravacy of palatal uncoverage in upper complete denture, palateless complete denture has some merits for upper edentulous patient. Following the uncovering of the palatal portion, the patient became easy to talk and restored the lost good tastes. He is happy despite of the decrease of the retention of the upper complete denture. Palateless complete denture is a compatible alternative for upper edentulous patients in cases of gagging, large palatal torus and restoring the lost good tastes. The clinical points are as follows : 1. The remaning alveolar ridge should be ovoid and have enough width and height for the support and retention. 2. The patient must have strong wish to the palateless complete denture. 3. Palatal beading made on the palatal peripheral border give good border sealing of the palatal flange and minimaized the prominence of the denture flange. 4. The peripheral border of the palatal flange should be reduced as thin as possible for more comfort. 5. Upper artificial posterior teeth should be arranged over the alveolar ridge crest and inner incline of the buccal cusp relieved for denture stability while chewing. 6. For stability of palateless complete denture, bilateral balanced occlusion should be sttained. Palateless complete denture will restore the lost good tastes and more comfortable and physiologic to upper edentulous patients and a good alternative to full palatal coverage complete denture in the properly selected cases.
Alveolar Process ; Denture Retention ; Denture, Complete* ; Dentures ; Gagging ; Humans ; Mastication ; Tooth

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An evaluation of angles between the alveolar crest bone and the implant effect on the implant crestal area induced stresses using a finite element method.

Sung Bum CHO ; Kyu Bok LEE ; Kwang Hun JO

The Journal of Korean Academy of Prosthodontics.2007;45(2):274-282.

STATEMENT OF PROBLEM: Main consideration was given to the stresses at the site of implant entry into the cortical bone at the alveolar crest. As a suspectible factor affecting the occurrence of stress concentrations, the contact angle between the implant and the alveolar crest bone was addressed. PURPOSE: The purpose of this study is to evaluate angles between the alveolar crest bone and the implant effect on the implant crestal area induced stresses using a finite element method. MATERIAL AND METHODS: Cylindrically shaped, standard size ITI implants entering into alveolar crest with four different contact angles of 0, 15, 30, and 45 deg. with the long axis of the implant were axisymmetrically modelled. Alterations of stresses around the implants were computed and compared at the cervical cortical bone. RESULTS AND CONCLUSION: The results demonstrated that regardless of the difference of the implant/alveolar crest bone contact angles, stress concentration occurred at the cervical bone and the angle differences led to insignificant variations in stress level.
Axis, Cervical Vertebra

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Alveolar bone changes around the natural teeth opposing the posterior implants in mandible.

Won Mo JUNG ; Dae Gon KIM ; Yang Jin YI ; Chan Jin PARK ; Lee Ra CHO

The Journal of Korean Academy of Prosthodontics.2007;45(2):263-273.

STATEMENT OF PROBLEM: Alteration of tooth function is assumed to be changed by stress/strain on the adjacent alveolar bone, producing changes in morphology similar to those described for other load-bearing bones. When teeth are removed, opposing teeth will not be functioned. When edentulous area is restored by implant prostheses, opposing teeth will be received physiologic mechanical stimuli. PURPOSE: The aim of this study was to evaluate the bone changes around the teeth opposing implant restoration installed mandibular posterior area. MATERIAL AND METHOD: Eight patients who had mandibular posterior edentulous area were treated with implants. Radiographs of the opposing teeth were taken at implant prostheses delivery(baseline), 3 months, and 6 months later. Customized film holding device was fabricated to standardize the projection geometry for serial radiographs of opposing teeth. Direct digital image was obtained. Gray values of region of interest at each digital image were measured and compared according to time lapse. Repeated measured analysis of variance and post-hoc Scheffe's test were performed at the 95% significance level. RESULTS: Alveolar bone changes around the natural teeth opposing the posterior implant in mandible showed statistically significant difference compared to control group(P<0.05). And gray values of alveolar bone around the teeth opposing implants were increased. There were no statistically significant differences of alveolar bone changes between crestal group and middle group and between mesial group and distal group according to time lapse(P>0.05). There were no statistically significant differences of alveolar bone changes among mesial-crestal group, mesial-middle group, distal-crestal group, distal-middle group, and control group(P>0.05). CONCLUSION: Alveolar bone around the natural teeth opposing the implant prosthesis showed gradual bony apposition.
Humans ; Mandible* ; Prostheses and Implants ; Tooth* ; Weight-Bearing

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Stability changes of immediately loaded and delayed loaded implants in edentulous mandible.

Hye Eun JUNG ; Dae Gon KIM ; Chan Jin PARK ; Lee Ra CHO ; Yang Jin YI

The Journal of Korean Academy of Prosthodontics.2007;45(2):250-262.

STATEMENT OF PROBLEM: It was reported high success rate of implant-supported fixed prostheses using with 5.6 implants on anterior mandible. Recently, immediate loading protocol was focused to overcome disadvantages of classic 2-stage delayed loading protocol. PURPOSE: This clinical study was to evaluate stability changes with time of immediately loaded and delayed loaded implants in edentulous mandible and to compare stability changes with time according to implantation sites. MATERIALS AND METHODS: Five or six implants were placed on anterior mandible depending on the arch shape. The immediately loading group was consisted of 8 patients received their prostheses within 24.48 hours after implantation. The delayed loading group was consisted of 8 patients received their definitive prostheses following classical prosthetic procedures after a healing period of 3 months. All patients were recalled every 6 months for check-up. The evaluations of radiographic examination, ISQ value measurement and recording of complication were done. To evaluate marginal bone level, intraoral periapical radiographs were taken with long cone paralleling technique. At every evaluation recall, all prostheses were removed and ISQ values were measured with Osstell(TM) on individual implants. RESULTS: 1. None of implants was failed. All implants showed stable marginal bone levels and ISQ values. 2. Marginal bone level changes with time showed statistically significant difference between immediately loading group and delayed loading group (P<0.001). 3. ISQ value changes with time did not show statistically significant difference between immediately loading group and delayed loading group (P=0.079). ISQ value decreased with time in both groups, however, all implants showed stable ISQ value at 30 months-recall evaluation. 4. Marginal bone level changes with time did not show statistically significant differences among implantation sites (P=0.604). 5. ISQ value changes with time showed statistically significant differences among implantation sites (P=0.047). ISQ values of most posterior implants decreased with time comparing to other implants. CONCLUSION: Although the marginal bone level of the terminal abutment didn't different with the other implants, ISQ value of the terminal abutment was lower than that of the other implants. Therefore, further clinical evaluation would be needed in this point of view.
Humans ; Mandible* ; Prostheses and Implants

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An influence of abutment materials on a screw-loosening after cyclic loading.

Tae Sik LEE ; Jung Suk HAN ; Jae Ho YANG ; Jae Bong LEE ; Sung Hun KIM

The Journal of Korean Academy of Prosthodontics.2007;45(2):240-249.

STATEMENT OF PROBLEM: A phenomenon of screw-loosening in implant abutment is frequently occurred in a single and multiple implant restoration. PURPOSE: This study was performed to evaluate an effect of abutment material on screw-loosening before and after a cyclic loading. In a single-tooth implant , different materials of abutment, Type III Gold alloy and Zirconium composite(ZrO2/Al2O3) were used. MATERIAL AND METHOD: The Gold alloy(Type III) and Zirconium composite(ZrO2/Al2O3) were used to make a superstructure of implant, the one of types of UCLA, Each group was constituted of 5 sample with a 30-degree offset angulated loading platform. The external hexagonal fixture was rigidly hel d in a special holding zig to ensure solid fixation without rotation during the tightening and a cyclic loading. A Titanium-alloy screw was used to connect and controlled to be tighten in 20Ncm torque by a digital torque gauge. A 20 times of consecutive closing/opening cycle were performed to evaluate the immediate torque loss. In 5 sample of each material group, an initial opening torque was recorded during 3 closing/opening cycle, then 2Hz, 200N, 1,000,000 cyclic loadings were performed, then a opening torque was evaluated. RESULT & CONCLUSION: 1. In this limited study, titanium alloy screw tightened in 20Ncm, a cold-welding phenomen on was not observed during the 20 times of closing/opening cycle(p=0.11, p=0.18). 2. In titanium alloy abutment screw, repeated opening and closing of the screw caused to progressive decrease of opening torque(p=0.014). 3. The difference in preload of screw between gold alloy abutment and ceramic(ZrO2/Al2O3) abutment was not significant(p=0.78). 4. The difference in torque loss of screw between gold alloy abutment and ceramic(ZrO2/Al2O3) abutment was not significant after 2Hz,200N, 1,000,000 cyclic loading(p=0.92). 5. In titanium alloy abutment screw tightened by 20Ncm, the screw loosening was not significant on each group after 2Hz, 200Ncm, 1,000,000 cyclic loading(p=0.59).
Alloys ; Dental Implants, Single-Tooth ; Titanium ; Torque ; Zirconium

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Morphometrics of alveolar process and anatomical structures around inferior maxillary sinus for maxillary implantation.

Ju Jin PARK ; Young Soo LEE ; Doo Jin PAIK ; Won Hee PARK ; Dong Yeob YOO

The Journal of Korean Academy of Prosthodontics.2007;45(2):228-239.

STATEMENT OF PROBLEM: Following tooth loss, the edentulous alveolar process of maxilla is affected by irreversible reabsorption process, with progressive sinus pneumatization leads to leaving inadquate bone height for placement of endosseous implants. Grafting the floor of maxillary sinus by sinus lifting surgery and augmentation of autologous bone or alternative bone material is a method of attaining sufficient bone height for maxillary implants placement and has proven to be a highty successful. PURPOSE: This study was undertaken to clarify the morphometric characteristics of inferior maxillary sinus and alveolar process for installation of implants. MATERIAL AND METHOD: Nineteen skulls (37 sinuses, 10M / 9F) obtained from the collection of the department of anatomy and cell biology of Hanyang medical school were studied. The mean age of the deceased was 69.9 years (range 44 to 88 years). The distance between alveolar border and inferior sinus margin at each tooth, the height of alveolar process and the thickness of cortical bone of the outer and inner table of alveolar process and the inferior wall of maxillary sinus were measured. RESULTS AND CONCLUSION: 1. The septum of inferior maxillary sinus were observe 28 sides (76.%) and located at the third molar (52.6%) and the second molar (26.3%). The deepest points of inferior border of maxillary sinus were located the first or second molar. The distance between alveolar margin and the deepest point of inferior maxillary sinus is 9.7 +/- 4.9 mm. 2. The length of the outer table of alveolar process were 4.9-28.2 mm and the shortest point was between the first and the second molors. The thickness of them were 0.9-3.2 mm. The length of the inner table of alveolar process were 7.4-25.8 mm and the shortest point was between the first and the second molars. The thickness of the were 0.9-4.6 mm. The results of this study are useful anatomical data for installing of maxillary implants.
Alveolar Process* ; Lifting ; Maxilla ; Maxillary Sinus* ; Molar ; Molar, Third ; Schools, Medical ; Skull ; Tooth ; Tooth Loss ; Transplants

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A 10-year retrospective clinical study of Branemark implants.

Jung Yoon BAE ; Sang Wan SHIN ; Hyun Jung CHO ; Young Soo KIM

The Journal of Korean Academy of Prosthodontics.2007;45(1):48-59.

STATEMENT OF PROBLEMS: There are few studies which reported the survival rates of the specific dental implant systems in the Korean population with the follow-up periods longer than 5 years. PURPOSE: This retrospective clinical study was aimed to evaluate cumulative survival rate (CSR) of Branemark implants followed for 10 years and to determine risk factors for implant failure. MATERIAL AND METHODS: A total of 271 Bra.nemark implants in 83 patients were investigated with several identified risk factors. Life table analysis was undertaken to examine the CSR. Cox regression method was conducted to assess the association between potential risk factors and overall CSR. RESULTS: Thirty implants failed. The 10-year implant CSR was 82.5%. Cox regression analysis demonstrated a significant predictive association between overall CSR and implant length (P<.05). CONCLUSION: An acceptable long-term result of Branemark implant was achieved and implant length showed a significant association with the CSR.
Dental Implants ; Follow-Up Studies ; Humans ; Life Tables ; Retrospective Studies* ; Risk Factors ; Survival Rate ; Treatment Outcome

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Novel treatment modality of implant-retained overdenture for immediate function in completely edentulous patients.

Jang Wook KIM ; Hyeong Seob KIM ; Jin BAIK ; Kung Rock KWON

The Journal of Korean Academy of Prosthodontics.2007;45(1):34-47.

STATEMENT OF PROBLEM: Conventional mandibular complete denture lacks in support and stability for edentulous patients to use. PURPOSE: To enhance support and stability of mandibular complete denture, 2 implants were inserted on the inter-mental foramina space of edentulous patients. With 2 magnetic attachments on the inner side of the overdenture, we gave immediate loads and evaluated the stability of the implants, the responses of the supporting tissues, and the satisfaction of the patients. MATERIAL & METHODS: 6 edentulous patients (5 male, 1 female) each recieved 2 SLA implants in the inter-mental foramina region and implants were immediately loaded with overdenture with magnet attachments. To evaluate the implants stability and the peri-implant tissues, clinical exams, RFA tests and radiographic exams were preformed at the 1 week, 2wks, 6wks, 12wks, and 24wks. post-surgery. RESULTS: The mean surgery time was 45.7 +/- 7.7 mins., while the denture delivery time was 45.5 +/- 12.6 mins. Only 2 of 14 implants were failed. Survived implants that remained were clincally and radiographically stable. Mean ISQ values were relatively stable, showing 69.71+/-5.55, 69.00+/-9.48, 67.92+/-7.86, 67.92+/-9.58, 70.08+/-7.61, 71.92+/-6.43 at the 1 wk, 2 wks, 6 wks, 12 wks, 24 wks. follow up check. Crestal bone changes were -1.18mm+/-0.68mm, -1.35+/-0.69mm, -1.47+/-0.68 mm at the 6wks, 12wks, 24wks. follow up check. Bleeding on probing(BOP index) was not significant. CONCLUSION: Mandibular ovedentures with 2 magnetic attachments over two interforaminal implants on edentulous patients for immediate function is a recommendable novel treatment for edentulous patients which shows stability on the implants and supporting tissue.
Denture, Complete ; Denture, Overlay* ; Dentures ; Follow-Up Studies ; Hemorrhage ; Humans ; Male

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Comparison of mechanical properties in 4 indirect composite resin.

Kil Soo KIM ; Tae Ho YOON ; Kwang Yeob SONG ; Seung Geun AHN

The Journal of Korean Academy of Prosthodontics.2007;45(1):21-33.

STATEMENT OF PROBLEM: The esthetic component of dental care has become increasingly more important, while new tooth-colored materials are continually marketed. Various new indirect composite materials have been developed with required advantages. The most recent development in the indirect composites has been the introduction of the second-generation laboratory composite or poly-glass materials. They are processed by different laboratory techniques based on combinations of heat, pressure, vacuum and light polymerization. Although, second generation products became available in 1995, their characteristics and clinical performance have not been adequately investigated. PURPOSE: The aim of this study was to measure the mechanical properties of the second generation indirect resin system and compare these with an existing universal direct composite resin. MATERIAL AND METHOD: In this study four indirect composite material (Adoro LC, BelleGlass HP, Tescera, Synfony) were tested for flexural strength, wear resistance, hardness and their degree of conversion against Z250, a light cure direct composite. RESULTS: Within the limitations of this study, the following conclusions were drawn: 1. From the abrasion wear result, Adoro showed the least volume loss while Synfony showed the greatest volume loss. Z250 and BelleGlass HP didn't show significant difference (p>0.05), but they showed significant difference with other groups (p<0.05). From the attrition wear, BelleGlass HP showed the least volume loss and it didn't show significant difference with Tescera (p>0.05). While Synfony showed the greatest volume loss that it showed significant difference with other groups (p>0.05). 2. Mean values of flexural strength by means of three point bending test was in the order of Z250, Adoro, Belleglass HP, Tescera and Synfony. Mean elastic modulus was in the order of Z250, BelleGlass HP, Tescera, Adoro and Synfony. 3. The result of Vicker's microhardness value showed that significantly higher value in Z250 (p<0.05), and is in the order of BelleGlass HP, Tescera, Adoro and Synfony. 4. The degree of conversion measured by FT-IR showed significantly higher value in BelleGlass HP (p<0.05), and is in the order of Adoro, Synfony, Tescera and Z250. CONCLUSION: Significant differences were found in the flexural strength, wear resistance, hardness and their degree of conversion.
Dental Care ; Elastic Modulus ; Hardness ; Hot Temperature ; Polymerization ; Polymers ; Vacuum

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