All-on-6 implant fixed prosthesis restoration with fulldigital system on edentulous patient: A case report / 대한치과보철학회지

All-on-six concept can be used as one of the treatment options to maximize the use of available residual alveolar bone for implant-supported fixed prosthesis on edentulous patients. But this process is complex and cumbersome. Digital system can be used at multiple steps, from implantation to prosthetic restoration, to overcome this shortcoming. In this case of a maxillary edentulous patient aged 76, digital system was used for restoration of 1-piece design, screw retained fixed prosthesis from diagnosis, implant surgery to fabrication of provisional and final prosthesis. For preoperative diagnosis and treatment planning stage, intra-oral information of a patient was digitalized by direct intra-oral scan. Surgical guide and immediate provisional prosthesis was designed based on this digitalized data. Patient’s inconvenience was minimized by applying immediate provisional prosthesis, which was delicately fabricated according to the location data of six implants on most suitable residual alveolar bone. Then, final prosthesis was designed and fabricated going through new interim prosthesis which was newly designed and fabricated, considering patient’s requests, stable vertical dimension and occlusion, and esthetic factors using digital system. We hereby report a case successfully applying digital system to multiple steps including implant surgery to fabricating prosthesis, to simplify existing complicated implant treatment procedure to an edentulous patient.

Radiographic evaluation of marginal bone level alteration around narrow implants placed in narrow alveolar ridge using guided flapless surgery / 대한치과보철학회지

Purpose@#The aim of this study was to compare radiographic outcomes around narrow-diameter implants placed using guided flapless surgery at longer than 6 month postplacement. @*Materials and Methods@#A total of 12 implants were assessed in 12 patients for the sites where 0.5 - 1.5 mm labial bone was covering the implants, using CBCT. @*Results@#A statistically significant preservation of crestal bone was observed in the narrow-diameter implants. @*Conclusion@#Guided flapless implant surgery may be important in preventing bone loss around the narrow-diameter implants that are placed in narrow alveolar ridges.

Effects of different surface finishing protocols for zirconia on surface roughness and bacterial biofilm formation

PURPOSE: Surface finishing of a zirconia restoration is essential after clinical adjustment. Herein, we investigated the effects of a surface finishing protocol for monolithic zirconia on final roughness and bacterial adherence. MATERIALS AND METHODS: Forty-eight disk-shaped monolithic zirconia specimens were fabricated and divided into four groups (n = 12) based on initial surface treatment, finishing, and polishing protocols: diamond bur+polishing bur (DP group), diamond bur+stone grinding bur+polishing bur (DSP group), no diamond bur+polishing bur (NP group), and no diamond bur+stone grinding bur+polishing bur (NSP group). Initial and final surface roughness was measured with a profilometer, and shown using scanning electron microscope. Bacterial adhesion was evaluated by quantifying Streptococcus mutans in the biofilm. Kruskal-Wallis and Mann-Whitney U tests were used to compare results among groups, and two-way analysis of variance was used to evaluate the effects of grinding burs on final roughness (α=.05). RESULTS: The DP group had the highest final Ra value, followed by the DSP, NP, and NSP groups. Use of the stone grinding bur as a coarse-finishing step significantly decreased final Ra values when a diamond bur was used (P < .001). Omission of the stone grinding bur increased biofilm formation on specimen surfaces. Combining a stone grinding bur with silicone polishing burs produced the smallest final biofilm values, regardless of the use of a diamond bur in initial surface treatment. CONCLUSION: Coarse finishing of monolithic zirconia with a stone grinding bur significantly decreased final Ra values and bacterial biofilm formation when surfaces had been roughened by a diamond bur.

All-on-4 implant restoration with full-digital system preserving existing occlusion: A case report / 대한치과보철학회지

In edentulous patients, implant - supported fixed prosthesis treatment has been proved to be useful, but involves complex treatment process. On the other hand, in the modern dentistry, digital technology has been developed day by day and it has expanded its range to the implant restoration of edentulous patients. In this case, a digital system was used for all stages of diagnosis, surgery, design and fabrication of provisional implants fixed prosthesis restoration in 66-year-old mandibular edentulous patients. In the preoperative diagnosis stage, a provisional restoration was designed based on the mucosal scan using the intraoral scanner and the stable occlusion of prefabricated complete denture of the patient. After flapless implant surgery using the surgical guide, the prefabricated interim restoration was connected to the implant and used as immediate provisional restoration. The final restoration was designed and fabricated by transferring the vertical dimension and the centric relation of the provisional restoration with stable occlusion using digital technology. We report a simple protocol of implant treatment in edentulous patients by using digital techniques to preserve the patient's vertical dimension and occlusion.

Application of digital implant system on implant treatment with “all-on-4” concept / 대한치과보철학회지

Recently, digital implant systems are expanding its influence in dental area. Due to technical improvement, they jumped over their limits nowadays. We can use these newest systems to treat edentulous patient, from implant surgery to fabrication of prosthesis. In this case, The patient was a fifty years old female. She had a full edentulous ridge on mandible and wanted to reconstruct occlusion with using implants. We planned to use digital implant system with “all-on-4” concept on mandible and produced surgical guide for flapless implant surgery. After the surgery, we tried to fabricate full arch prosthesis just using a digital devices and confirmed satisfying result.

Implant prosthesis for fully edentulous patients using intra-oral scanning and abutment merging technique: A case report / 대한치과보철학회지

In this case, the impression surface of the existing denture was scanned and was inverted three-dimensionally to express the residual ridge form. Implant planning was performed on the superimposed data of the CT with the scanned image of the denture with radiopaque markers attached. At the day of surgery, customized abutments fabricated in accordance with the form of the gingival margin were linked with fixtures and temporary restorations were set. In the process of fabricating the final prosthesis after the osseointegration of implant fixture, the intraoral scan images at abutment level were merged with images of the abutments scanned and stored before implant surgery. By fabricating the final prosthesis with the abutments obtained by merging can increase the marginal fitness of the final prosthesis and simplify the clinical process.

Verification of a computer-aided replica technique for evaluating prosthesis adaptation using statistical agreement analysis

PURPOSE: The purpose of this study was to evaluate the reliability of computer-aided replica technique (CART) by calculating its agreement with the replica technique (RT), using statistical agreement analysis. MATERIALS AND METHODS: A prepared metal die and a metal crown were fabricated. The gap between the restoration and abutment was replicated using silicone indicator paste (n = 25). Gap measurements differed in the control (RT) and experimental (CART) groups. In the RT group, the silicone replica was manually sectioned, and the marginal and occlusal gaps were measured using a microscope. In the CART group, the gap was digitized using optical scanning and image superimposition, and the gaps were measured using a software program. The agreement between the measurement techniques was evaluated by using the 95% Bland-Altman limits of agreement and concordance correlation coefficients (CCC). The least acceptable CCC was 0.90. RESULTS: The RT and CART groups showed linear association, with a strong positive correlation in gap measurements, but without significant differences. The 95% limits of agreement between the paired gap measurements were 3.84% and 7.08% of the mean. The lower 95% confidence limits of CCC were 0.9676 and 0.9188 for the marginal and occlusal gap measurements, respectively, and the values were greater than the allowed limit. CONCLUSION: The CART is a reliable digital approach for evaluating the fit accuracy of fixed dental prostheses.

The effect of low-speed drilling without irrigation on heat generation: an experimental study

OBJECTIVES: In this study we evaluated heat generation during the low-speed drilling procedure without irrigation. MATERIALS AND METHODS: Ten artificial bone blocks that were similar to human D1 bone were used in this study. The baseline temperature was 37.0degrees C. We drilled into 5 artificial bone blocks 60 times at the speed of 50 rpm without irrigation. As a control group, we drilled into an additional 5 artificial bone blocks 60 times at the speed of 1,500 rpm with irrigation. The temperature changes during diameter 2 mm drilling were measured using thermocouples. RESULTS: The mean maximum temperatures during drilling were 40.9degrees C in the test group and 39.7degrees C in the control group. Even though a statistically significant difference existed between the two groups, the low-speed drilling did not produce overheating. CONCLUSION: These findings suggest that low-speed drilling without irrigation may not lead to overheating during drilling.

Accuracy assessment of implant placement using a stereolithographic surgical guide made with digital scan / 대한치과보철학회지

PURPOSE: The objective of this study was to evaluate the accuracy of a stereolithographic surgical guide that was made with information from intraoral digital impressions and cone beam CT (CBCT). MATERIALS AND METHODS: Six sets of resin maxilla and mandible models with missing teeth were used in this study. Intraoral digital impressions were made. The virtual models provided by these intraoral digital impressions and by the CBCT scan images of the resin models were used to create a surgical guide. Implant surgery was performed on the resin models using the surgical guide. After implant placement, the models were subjected to another CBCT scan to compare the planned and actual implant positions. Deviations in position, depth and axis between the planned and actual positions were measured for each implant. RESULTS: The mean deviation of the insertion point and angulation were 0.28 mm and 0.26degrees, apex point were 0.11 mm and 0.14 mm respectively. The implants were situated at a mean of 0.44 mm coronal to the planned vertical position. CONCLUSION: This study demonstrates that stereolithographic surgical guides created without the use of impressions and stone models show promising accuracy in implant placement.

Immediate restorations in a fully edentulous patient utilizing digital system: A case report / 대한치과보철학회지

This article describes how to use CBCT and an intraoral scanner in a fully edentulous case that enables the clinician to place implants with flapless guided surgery and to engage prefabricated, customized implant abutments at the time of implant surgery, with only 1 clinical consultation before implant surgery. The patient's existing denture is used to simulate the teeth, the soft tissue and the vertical dimension of occlusion, and jaw relationship in the fully edentulous jaw. It provides clinicians with a fast workflow and improves clinical efficiency.

The effect of guided flapless implant procedure on heat generation from implant drilling / 대한치과보철학회지

PURPOSE: The aim of this study was to evaluate the heat generation in bone in vitro during the guided flapless drilling procedure and the effect of drilling methods on the heat generation. MATERIALS AND METHODS: A model that has missing the first and second mandibular molars bilaterally was used. In group A, classical flap implant surgery was performed. In group B, flapless implant surgery using surgical guide was performed. In group C, flapless implant surgery using surgical guide without up-and-down pumping motion was performed. Temperature was measured with k-type thermocouple and a real-time digital thermometer. The thermocouples were placed at 0.5 mm away from the osteotomy area at the depths of 3 mm and 6 mm. The measured values were evaluated with independent t-test. RESULTS: The mean temperature generated was 27.2degrees C (SD +/- 2.1degrees C) and 27.5degrees C (SD +/- 2.3degrees C) for groups A and B, respectively. These differences were not statistically significant. In group C, the mean temperature was 37.0degrees C (SD +/- 3.4degrees C). There were statistically significant differences between groups B and C with respect to the mean temperature. CONCLUSION: These findings suggest that guided flapless drilling with up-and-down pumping motion may not significantly increase the bone temperature.

Evaluation of the accuracy of two different surgical guides in dental implantology: stereolithography fabricated vs. positioning device fabricated surgical guides / 대한치과보철학회지

PURPOSE: Recently implant surgical guides were used for accurate and atraumatic operation. In this study, the accuracy of two different types of surgical guides, positioning device fabricated and stereolithography fabricated surgical guides, were evaluated in four different types of tooth loss models. MATERIALS AND METHODS: Surgical guides were fabricated with stereolithography and positioning device respectively. Implants were placed on 40 models using the two different types of surgical guides. The fitness of the surgical guides was evaluated by measuring the gap between the surgical guide and the model. The accuracy of surgical guide was evaluated on a pre- and post-surgical CT image fusion. RESULTS: The gap between the surgical guide and the model was 1.4 +/- 0.3 mm and 0.4 +/- 0.3 mm for the stereolithography and positioning device surgical guide, respectively. The stereolithography showed mesiodistal angular deviation of 3.9 +/- 1.6degrees, buccolingual angular deviation of 2.7 +/- 1.5degrees and vertical deviation of 1.9 +/- 0.9 mm, whereas the positioning device showed mesiodistal angular deviation of 0.7 +/- 0.3degrees, buccolingual angular deviation of 0.3 +/- 0.2degrees and vertical deviation of 0.4 +/- 0.2 mm. The differences were statistically significant between the two groups (P<.05). CONCLUSION: The laboratory fabricated surgical guides using a positioning device allow implant placement more accurately than the stereolithography surgical guides in dental clinic.

The effects of tissue punch diameter on healing around implants in flapless implant surgery / 대한치과보철학회지

STATEMENT OF PROBLEM: Flapless implant surgery using a soft tissue punch device requires a circumferential excision of the mucosa at the implant site. To date, Although there have been several reports on clinical outcomes of flapless implant surgeries, there are no published reports that address the appropriate size of the soft tissue punch for peri-implant tissue healing. PURPOSE: In an attempt to help produce guidelines for the use of soft tissue punches, this animal study was undertaken to examine the effect of soft tissue punch size on the healing of peri-implant tissue in a canine mandible model. MATERIAL AND METHODS: Bilateral, edentulated, flat alveolar ridges were created in the mandibles of six mongrel dogs. After a three month healing period, three fixtures (diameter, 4.0 mm) were placed on each side of the mandible using 3 mm, 4 mm, or 5 mm soft tissue punches. During subsequent healing periods, the peri-implant mucosa was evaluated using clinical, radiological, and histometric parameters, which included Gingival Index, bleeding on probing, probing pocket depth, marginal bone loss, and vertical dimension measurements of the peri-implant tissues. RESULTS: The results showed significant differences (P or = 4 mm. CONCLUSION: Within the limit of this study, the size of the soft tissue punch plays an important role in achieving optimal healing. Our findings support the use of tissue punch that 1 mm smaller than implant itself to obtain better peri-implant tissue healing around flapless implants.

A systematic implant treatment planning and concepts for clinical success / 대한치과보철학회지

STATEMENT OF PROBLEM: It is important to have a correct presurgical treatment plan before any implant surgery. It must contain substantial information about the patient concerned. However, the standard classification only notifies the dentist about various structural, pathological and physiological dimensions. Due to diverse structure of the jaw bone, current standard classification does not tell spatial dimensions of the available bone for implant insertion sites. PURPOSE OF STUDY: The purpose of this study is to report the establishment of the systematic implant treatment plan and its clinical treatment using Implan(R) program which is based on ASCIi-classification that is available for future diagnosis and scale of treatment and for systematic implant insertion. RESULTS: By assisting the systemic measurement of the available alveolus dimension during implant surgery, it was easy to set initial implant treatment plan. CONCLUSION: Using Implan(R) program which is based on ASCIi-classification system that allows the establishment of systemic implant treatment plan and successful clinical performance, it was possible to establish the founding of initial implant treatment plan, the acquisition of information, and the systematization of documentation.

Dimensional stability of impression body using silicone index tooth tray impression system / 대한치과보철학회지

STATEMENT OF PROBLEM: Silicone Index Tooth Tray impression system which does not use gingicord has a shortcoming. It takes time to remove internal wall of Silicone Index Tooth Tray for space of wash impression material. PURPOSE: This study was to evaluate whether providing certain space to impression body can prevent from doing complicated laboratory work. MATERIAL AND METHODS: After mounting metal dies with shoulder and chamfer margins arbiturarily, SITT was produced using Blu-mousse(R). In one experimental group, wash impression was taken using Fit-tester(R) without removing interior surface of SITT and in the other group, wash impression was taken using Fit-tester(R) providing 0.5mm space in the SITT and then compared the differences in two groups. RESULTS: 1. There was no significant difference between a group which did not allow space and a group which granted equal 0.5mm space. 2. There was no significant difference between gingival diameter, occlusal diameter of metal die that has shoulder margin and gingival diameter, occlusal diameter of metal die that has chamfer margin. 3. There was no significant difference between a group which did not take pick-up impression and a group which took pick-up impression through relining method using SITT. 4. There was no significant difference between a group that poured immediately after taking primary impression and a group that poured after removing poured stone die. CONCLUSIONS: When taking an impression of an abutment using SITT impression system, it is considered to obtain clinically identical results between a group that did not grant a 0.5mm space within SITT for wash impression and a group which invest a space. Furthermore, it is considered possible to produce an individual die through secondary pouring.

Finite element stress analysis of implant prosthesis according to platform width of fixture / 대한치과보철학회지

STATEMENT OF PROBLEM: With increasing demand of the implant-supported prosthesis, it is advantageous to use the different platform width of the fixture according to bone quantity and quality of the patients. PURPOSE: The purpose of this study was to assess the loading distributing characteristics of two implant designs according to each platform width of fixture, under vertical and inclined loading using finite element analysis. Material and method : The two kinds of finite element models were designed according to each platform width of fixture (4.1mm restorative component x 11.5mm length, 5.0mm wide-diameter restorative component x 11.5mm length). The crown for mandibular first molar was made using UCLA abutment. Each three-dimensional finite element model was created with the physical properties of the implant and surrounding bone. This study simulated loads of 200N at the central fossa in a vertical direction, 200N at the outside point of the central fossa with resin filling into screw hole in a vertical direction and 200N at the buccal cusp in a 300 transverse direction individually. Von Mises stresses were recorded and compared in the supporting bone, fixture, and abutment screw. RESULTS: The stresses were concentrated mainly at the cortex in both vertical and oblique loading but the stresses in the cancellous bone were low in both vertical and oblique loading. Bending moments resulting from non-axial loading of dental implants caused stress concentrations on cortical bone. The magnitude of the stress was greater with the oblique loading. Increasing the platform width of the implant fixture decreased the stress in the supporting bone, fixture and abutment screw. Increased the platform width of fixture decreased the stress in the crown and platform. CONCLUSION: Conclusively, this investigation provides evidence that the platform width of the implant fixture directly affects periimplant stress. By increasing the platform width of the implant fixture, it showed tendency to decreased the supporting bone, fixture and screw. But, further clinical studies are necessary to determine the ideal protocol for the successful placement of wide platform implants.

Evaluation of the fracture resistance of all-ceramic zirconia posts by 3 different methods / 대한치과보철학회지

STATEMENT OF THE PROBLEM: All-ceramic post-and-core restorations offer a number of advantages compared with systems that use metal build-ups. In certain clinical cases, however, fractures at the joint between the post and core build-up have been reported. PURPOSE: The objective, therefore, is to improve the joint between the post and the core build-up. MATERIAL AND METHODS: Three different methods were used to prepare all-ceramic post-andcore restorations; pressing IPS Empress core build-ups to CosmoPost zirconia posts, cementing IPS Empress core build-ups to CosmoPost zirconia posts and Celay-milling of zirconia blanks. A series of ten restorations was prepared for each of the three methods. The post-and-core complexes were tested to failure with the load applied perpendicular to the post axis. The load and deflection at fracture were recorded. RESULTS: The highest breaking load and highest deflection were recorded for the cementing technique with values of 25.3 N and 394 micrometer, respectively. The corresponding values for the pressed core build-ups and the milled zirconia core build-ups were 22 N and 301 micrometer, and 13 N and 160 micrometer, respectively. All the differences are statistically significant (p=0.05). Regarding the load-dependence of the deflection, the cemented core build-ups again demonstrated the highest value with 15.5 micrometer/N. The difference in the values of 13.6 micrometer/N and 13 micrometer/N recorded for the pressed-on and milled core build-ups, respectively, were statistically insignificant. CONCLUSION: In regard to the high fracture resistance of zirconia post, adhesive cementing the core build-up to the post offers a viable alternative to the conventional pressing technique. The elastic bond between the rigid high-strength zirconia post and the core build-up presents an additional advantage.

Clinical application of a new systematic implant planning concept (A Clinical Report) / 대한치과보철학회지

STATEMENT OF PROBLEM: Commonly used classification systems do not inform fo dentists the dimension of the available bone at a potential implant site although regarding a variety of morphologic and pathophysiologic aspects using schematic graphs. However, for the implantologist the availability of bone substance is most important independent whether it concerns the jaw basis or the alveolus. PURPOSE OF STUDY: The present article refers to a new evaluation form, to analyze the available bone with regard to optional immediate loading site by site. According to a new systematic implant planning concept will be presented in two case reports. RESULTS: The feasibility of the classification for planning and documentation of immediately loaded implants is presented in two case reports. CONCLUSION: The factor of bone support for immediate functional stability is important in dental implantology. The new systematic implant planning helps to systematically estimate the dimension (ASCIi classification) of the alveolus site by site to evaluate the possibility of immediate loading. The G ttingen classification thus aids to determine the degree of stability that can be expected for the planned solution.

Anatomical Site Classification for Implant Insertion: ASCII / 대한치과보철학회지

STATEMENT of PROBLEM: As a standard means of diagnostics, an orthopantomogram(OPT) permits to measure the vertical and mesiodistal dimension of available bone at the desired implant site with the help of suitable radioopaque references. Based on the clinical investigation of the dentition and the edentulous sites, information upon the width of the implant site can be obtained and documented in the dental scheme. Both findings permit together systematic primary planning for endosteal implants. PURPOSE of STUDY: Contents of the present article are the representation of a semiquantitative classification of available bone with the aim to simplify the primary phase of a systematic implant planning. RESULTS: Thus the ASCII-system permits a clear protocol of bone findings for the implant case with all information available during the primary appointment for treatment planning as a basis of further diagnostic and therapeutic measures. CONCLUSION: With the ASCII system, important parameters such as alveolar height and subcrestal alveolar width can be documented systematically, easily and time saving in the dental scheme as a basis for exact treatment planning.