임프란트와 인접 자연치 사이의 근심 접촉 소실에 관한 임상연구

Proximal contact loss between an adjacent natural tooth and fixed implant prosthesis can be experienced during treatment, especially in the case of posterior prostheses following implant placement. Since the implant prostheses are fixed in the jaw bone, contact loss is most likely caused by mesial migration of the anterior adjacent tooth. It could be considered that there is some reason beyond the natural mesial drift after implant prostheses delivery, since contact loss is not often observed in the natural dental arch. Food impaction caused by proximal contact loss frequently leads to patient discomfort and periodontal disease. According to Hua Wei(2008), occlusal force distribution, periodontal status, and masticatory habits affect proximal contact loss between the adjacent natural tooth and the fixed implant prosthesis. This study examined the records of patients who received implant treatment at the Department of Prosthodontics in Kangnam Severance Hospital. The ratio, period, and area of proximal contact loss were evaluated.ope

Short implant의 식립 후 1년간의 골흡수 비교연구

Based on the rapid progress made in research concerning implant fixture designs and surface treatments, modern implant treatments have progressed significantly and are now capable of overcoming anatomical limitations and ensuring a stable prognosis. But for cases where patients suffer severe alveolar bone loss in molar areas, many problems still exist. Therefore, short implants (less than 10mm in fixture length) are increasingly being accepted as an alternative option. In spite of the extensive number of studies reporting high success rates using short implants, there are still many risk factors, including 1) reduced bone-implant contact area and 2) reduced stress distribution around the implant fixture and 3) poor prognosis due to poor bone quality. The present study evaluated marginal bone changes in radiographic images of 40 single short implant cases selected from among 389 short implant cases installed in Yongdong Severance Dental Hospital from 2003. Comparisons with standard implants (more than 10mm in length) with 1-year follow up were performed. Additionally, the effects of crown-to-implant ratio in short implants were also evaluatedope

The level of buccal gingival margin around single and two adjacent implant restorations: a preliminary result

STATEMENT OF PROBLEM: Little information is available about the buccal gingival level of multiple implant restorations. PURPOSE: This study was aimed to evaluate the relationship between width and height of buccal soft tissue around single and 2 adjacent implant restorations. MATERIAL AND METHODS: Four implant restoration groups (first and second molars, single second molars, posterior single restorations between teeth, and anterior single restorations between teeth) were randomly chosen from one dental institute. Each group comprised of 6 patients. After 6 months of function, silicone impressions were taken and stone models were fabricated for each restoration group. The stone models were cut in bucco-lingual direction at the most apical point of buccal gingival margin. The height and width of buccal supra-implant soft tissue were measured. One way ANOVA and Tukey HSD post hoc tests were performed to analyze the data obtained (P < .05). RESULTS: The most unfavorable width-height ratio was noted for the group, which was comprised of the second molar in the multiple adjacent (first and second molar) implant-supported restorations. The group also resulted in the shorter height of buccal supra-implant mucosa rather than that of anterior single implant restorations between natural teeth. CONCLUSION: To achieve a favorable level of buccal gingival margin, greater thickness of buccal supra-implant mucosa is required for the implant restorations without a neighboring natural tooth compared to the implant restorations next to a natural tooth.ope

Peri-Implant Bone Level Changes of Scalloped Implant: A Retrospective Radiographic Study

Purpose: The aim of this study is to investigate changes in the marginal bone level where a scalloped implant was placed as well as to evaluate the influencing factors, such as time of placement or area of placement. Materials and Methods: The participants of this study included patients who received a scalloped implant from April 2011 to October 2012 and visited the Department of Prosthodontics, Gangnam Severance Dental Hospital after over 12 months. The survival rate and changes of mesial and distal marginal bone levels were calculated. In addition, the factors influencing the marginal bone level were evaluated according to the time of placement, area of placement and time. Subsequently, a statistic analysis was performed using an independent t-test and a linear mixed model. The significant level was 95%. Results: Thirty-five patients with 43 scalloped implants were included in this retrospective study. Changes of marginal bone level were 0.34 mm mesially and 0.29 mm distally. There were no statistically significant differences among all of the influencing factors, except for time. Conclusion: In conclusion, the present study suggests that the use of scalloped implant can be a predictable treatment option even in areas where mild dehiscence exists on the buccal plate.ope

The change of rotational freedom following different insertion torques in three implant systems with implant driver.

STATEMENT OF PROBLEM: Implant drivers are getting popular in clinical dentistry. Unlike to implant systems with external hex connection, implant drivers directly engage the implant/abutment interface. The deformation of the implant/abutment interface can be introduced while placing an implant with its implant driver in clinical situations. PURPOSE: This study evaluated the change of rotational freedom between an implant and its abutment after application of different insertion torques. MATERIAL AND METHODS: Three kinds of internal connection implants were utilized for the current study (4.5 × 12 mm Xive, 4.3 × 11.5 mm Inplant Magicgrip, 4.3 × 12 mm Implantium MF). An EstheticBase, a 2-piece top, a Dual abutment was used for its corresponding implant system. The rotational freedom between an implant and its abutment were measured before and after applying 45, 100 Ncm insertion torque. Repeated measures ANOVA was used for statistical analysis. RESULTS: Under 45 Ncm insertion torque, the rotational freedom between an implant and its abutment was significantly increased in Xive (P = .003). However, no significant change was noted in Inplant Magicgrip and Implantium MF. Under 100 Ncm torque, both in Xive (P = .0005) and Implatium MF (P = .03) resulted in significantly increased rotational freedom between the implant and its abutment. DISCUSSION: The design of the implant/implant driver interface effectively prevented the deformation of implant/abutment interface. Little change was noted in the rotational freedom between an implant and its abutment, even though the insertion torque was far beyond clinical application. CONCLUSIONS: The implant/abutment joint of internally connecting implants were quite stable under insertion torque in clinical situation.ope

1-Piece Implant

Prosthodontic treatment using implants has many advantages in comparison with conventional treatment. However, it is reported that there are several complications associated with implants. They are divided into mechanical, biological, and esthetic aspects in prosthodontics. To overcome them, there have been numerous attempts such as a connection type of abutment-fixture, microthread, crestal module design, and abutment profile. Recently, one of the methods involves the development of a 1-piece implant. A 1-piece implant has many advantages in comparison with previous 2-piece implant. It is free of mechanical complications such as screw looseness, screw fracture, and fixture fracture. Also, in a biological aspect, absence of microgap, micromovement, and dis/reconnection of abutment leads to the stable maintenance of soft and hard tissue. However, 1-piece implants have limited indications. Selection of abutment is very strict and correction of the path is difficult after the installation of the fixture. Also, bone quality and primary stability are very important factors in 1-piece implants because it is based on immediate provisionalization. Although there are not many kinds of available 1-piece implants, one of the most well-known 1-piece implants is NobelDirect® (Nobel Biocare). However, clinical results of NobelDirect® are controversial and improvement is necessary. In most studies, it is reported that long term studies and improvements of implant design are required. Therefore, this research focuses on the advantages, design, clinical application and practical result of 1-piece implants.ope

Impact of immediate and non-immediate provisionalization on the soft tissue esthetics of final restorations on immediately placed implants

STATEMENT OF PROBLEM: Interpoximal papilla could be re-established without immeidate support with a provisional resotration following an immdiate implant placement. PURPOSE: Successful esthetic outcomes were reported utilizing immediate provisionalization following immediate implant placements. The aim of this study was to evaluate the soft tissue esthetics around immediately placed single tooth implant restorations with or without immediate provisional restorations. METHODS: A total of ten patients, who had a hopeless maxillary anterior tooth, were enrolled in this study. Screw retained provisional restorations were delivered to the randomly chosen 5 patients (immediate provisionalization group) on the day of immediate implant placement and maintained for about 5 months. For the remaining five patients (non-immediate provisionalization group), healing abutments were delivered on the day of surgery, replaced with screw retained provisional restorations approximately 3 months afterwards, and the provisional restorations were maintained for about 3 months. Digital photographs were taken at the delivery of final restorations in order to assess following variables; mesial papilla, distal papilla, soft tissue level, soft tissue contour and facial soft tissue prominence. The variables were compared to those of the contralateral natural tooth and scored by prosthodontists, periodontists, orthodontists and dental students. RESULTS: The immediate provisionalization group marked significantly higher scores on the following variables; soft tissue level and facial soft tissue prominence. In evaluating each variable, there were no notable differences in opinion between four dentist groups. CONCLUSION: Immediate provisionalization can be a treatment option to achieve superior soft tissue esthetics around immediately placed single implant restorations rather than non-immediate provisionalization approachesope

(A) study on shear bond strength of interface between bone and titanium plasma sprayed IMZ implant in rabbits

치의학과/박사[한글] 본 실험은 원주형의 titanium Plasma spray 처리 된 치과용 titanium 임프란트(IMZ)를 IMZ회사에서 추천하는 이식방법을 대조군으로, 임프란트보다 큰 골결손 부위 형성 후 이식방법을 실험 Ⅰ군으로, 임프란트 이식 후 골결손 부위에 다공성 hydroxyapatite 입자(I nterpore 200** )를 동시에 이식하는 방법을 실험 Ⅱ군등 세군으로 나누어 가토의 대퇴골에 이식하여 8주 후 동물을 회생시켜 임프란트와 임프란트주위 조직사이의 전단강도를 pushout test로 측정 비교하였고, 또한 각군을 조직학적으로 관찰하여 다음과 같은 결과를 얻었다. 1. Titanium 임프란트와 주위조직 간의 전단강도는 대조군에서는 2.614±0.680 MPa, 실험 Ⅰ군에서는 0.664±0.322 MPa, 실험 Ⅱ군 2.281±0.606 MPa이었으며, 대조군과 실험 Ⅰ군, 실험 Ⅰ군과 실험 Ⅱ군은 통계학적 유의한 차이가 있었으며, 대조군과 실험 Ⅱ군은 유의한 차이가 없었다. 2. 3개군의 titanium 임프란트 주위의 골형성은 수질골보다 피질골에서 더 진행되었다. 3. 대조군과 실험 Ⅱ군의 비탈희 표본의 조직학적 소견은 계면의 50% 이상에서 골과 유골 형성이 관찰되었다. 4. 실험 Ⅰ군 비탈희 표본의 조직학적 소견은 계면의 50% 이하에서 골과 유골 형성이 관찰되었으며, 상부에서 부분적인 골결손이 관찰되었다. 5. 실험 Ⅱ군에서 다공성 HA입자 주위에 직접적인 골접촉 양상을 보였고, 부분적으로 거대 세포침윤이 관찰되었다. 6. Titanium 임프란트 및 다공성 HA입자 주위에서 염증세포는 관찰되지 않았다. Titanium 임프란트 주위에 골결손부를 임의로 형성하여 다공성 HA입자를 이식한 경우 임프란트만 이식한 경우에 비하여 골형성이 보다 많았으며, 임프란트와 골의 결합력이 컸다. A STUDY ON SHEAR BOND STRENGTH OF INTERFACE BETWEEN BONE AND TITANIUM PLASMA SPRAYED IMZ IMPLANT IN RABBITS Chong - Hyun Han Dept. of Dental Science, Graduate School, Yonsei University (Directed by Dong-Hoo Han, D.D.S., M.S.D., Ph.D.) In recent years immediate implantation has been tried by a few clinicians. This study placed IMZ implants in the rabbit femur with and without bony defects around the implant for simulating fresh extraction site. And one group with bony defects used porous hydroxyapatite granules(HA) to fill in, and the other group left the bony defects around the implant. The purpose of this study was to compare the shear bond strength and the bony contact and formation around the implant. Fifteen rabbits were divided into three groups and placed 10 IMZ implants to each group. Implant sites were surgically prepared with IMZ drills kit and implants were placed(Control), artificial bony defect was created with Apaceram drills kit around the implant sites and implants were placed(Experimental Ⅰ), bony defect was filled with porous hydroxyapatite granules(Experimental Ⅱ). Thereafter, rabbits were sacrificed at 8th week and specimens were prepared and pushout tested for shear band strength of bone - implant interface immediately. Undecalcified and decalcified specimens were prepared with Vilanueva and hematoxylin - eosin stain for light microscopic finding. The results of this study were as follows. 1. In the control group, mean shear strength of bone - implant interface was 2.614±0.680 MPa, experimental Ⅰ was 0.664±0.322 MPa, and experimental Ⅱ was 2.281±0.606 MPa. There was significant difference between control and experimental Ⅰ, between experimental Ⅰ and experimental Ⅱ, but did not show significant difference between control and experimental Ⅱ statistically. 2. In the bony formation surrounding IMZ implant of the three groups, that of cortical bone is more advanced than cancellous bone area 3. In the histological findings of undecalcifed specimens, control and experimental Ⅱ showed more than 50% of bony or osteoid formation at the bony - implant interface. 4. In the histological findings of undecalcified specimens, experimental Ⅰ showed less than 50% of bony or osteoid formation at the interface, and observed partial bony defect in the coronal zone. 5. In the experimental Ⅱ group, were observed direct bony contact to hydroxyapatite granules, and infiltration of a few giant cells. 6. No imflammatory responses were seen around the titanium implants and the hydroxyapatite granules. [영문] In recent years immediate implantation has been tried by a few clinicians. This study placed IMZ implants in the rabbit femur with and without bony defects around the implant for simulating fresh extraction site. And one group with bony defects used porous hydroxyapatite granules(HA) to fill in, and the other group left the bony defects around the implant. The purpose of this study was to compare the shear bond strength and the bony contact and formation around the implant. Fifteen rabbits were divided into three groups and placed 10 IMZ implants to each group. Implant sites were surgically prepared with IMZ drills kit and implants were placed(Control), artificial bony defect was created with Apaceram drills kit around the implant sites and implants were placed(Experimental Ⅰ), bony defect was filled with porous hydroxyapatite granules(Experimental Ⅱ). Thereafter, rabbits were sacrificed at 8th week and specimens were prepared and pushout tested for shear band strength of bone - implant interface immediately. Undecalcified and decalcified specimens were prepared with Vilanueva and hematoxylin - eosin stain for light microscopic finding. The results of this study were as follows. 1. In the control group, mean shear strength of bone - implant interface was 2.614±0.680 MPa, experimental Ⅰ was 0.664±0.322 MPa, and experimental Ⅱ was 2.281±0.606 MPa. There was significant difference between control and experimental Ⅰ, between experimental Ⅰ and experimental Ⅱ, but did not show significant difference between control and experimental Ⅱ statistically. 2. In the bony formation surrounding IMZ implant of the three groups, that of cortical bone is more advanced than cancellous bone area 3. In the histological findings of undecalcifed specimens, control and experimental Ⅱ showed more than 50% of bony or osteoid formation at the bony - implant interface. 4. In the histological findings of undecalcified specimens, experimental Ⅰ showed less than 50% of bony or osteoid formation at the interface, and observed partial bony defect in the coronal zone. 5. In the experimental Ⅱ group, were observed direct bony contact to hydroxyapatite granules, and infiltration of a few giant cells. 6. No imflammatory responses were seen around the titanium implants and the hydroxyapatite granules.restrictio

Three-dimensional Stress Analysis of Implant Systems with Micro Threads in the Maxillary Bone

A comparative study of stress distributions in the maxillary bone with three different types of abutment was conducted. Finite element analysis was adopted to determine stress generated in the bone with the different implant systems with micro threads (Onebody type implant, Internal type implant, and External type implant). It was found that the types of abutments and the number of micro threads have significant influence on the stress distribution in the maxillary bone. They were due to the difference in the load transfer mechanism and the size of contact area between abutment and fixture. Also the maximum effective stress in the maxillary bone was increased with increasing inclination angle of load. It was concluded that the maximum effective stress in the bone was the lowest by the internal implant among the maximum effective stresses by other two types of implants and by appropriate number of micro threads, and that the specific number of micro thread was existed to decrease the maximum effective stress in the maxillary bone due to different implant systems and loading conditions.ope

A Study on Shear-Bond Strength of the Interface Between Bone and Titanium Plasma-Sprayed IMZ Implants in Rabbits

In this study, cylindrical titanium plasma-sprayed dell implants were divided into three groups and implanted in rabbit femurs as: (1) control, a conventional method recommended by IMZ, (2) experimental I, artificial bone defects were formed prior to implantation, and (3) experimental II, porous hydroxyapatite (HA) granules were grafted into bone defects after implantation. The rabbits were sacrificed after 8 weeks and specimens were prepared and immediately pushout-tested for shear-bond strength of the bone-implant interface. Each group was examined histologically. The results showed that mean shear strength of the bone-implant interface in the control group was 2.61 ± 0.68 MPa, in experimental I was 0.66 ± 0.32 MPa, and in experimental II was 2.28 ± 0.60 MPa. There was a significant difference between the control and experimental I and between experimental I and experimental II, but no statistically significant difference between the control and experimental II. Cortical bone formation was more advanced than cancellous bone around the implants. In the histologic study of nondecalcified specimens, control and experimental II groups showed about 55% bone or osteoid tissue in contact with titanium at the bone-implant interface. In the histologic review of undecalcified specimens, the experimental I group demonstrated about 45% bone or osteoid tissue in contact with titanium at the interface, and partial bony defects were seen in the coronal zone. In the experimental II group, direct bony contact to HA granules and infiltration of a few giant cells were seen. When porous HA granules were grafted in the randomly made bone defects around the titanium implants, bone growth was more active and implant-bone bond strength was greater than when only the implants were placed.restrictio