STATEMENT OF PROBLEM: The aim of this study was to study the effects of various surface treatments to a titanium surface on the expression of Runx2 in vitro. MATERIAL AND METHODS: Human Osteosarcoma TE-85 cells were cultured on machined, sandblasted, or anodic oxidized cpTi discs. At various times of incubation, the cells were collected and then processed for the analysis of mRNA expression of Runx2 using reverse transcription-PCR. RESULTS: The expression pattern of Runx2 mRNA was differed according to the types of surface treatment. When the cells were cultured on the untreated control culture plates, the gene expression of Runx2 was not increased during the experiments. In the case of that the cells were cultured on the machined cpTI discs, the expression level was intermediate at the first day, but increased constitutively to day 5. In cells on sandblasted cpTi discs, the expression level was highest in the first day sample and the level was maintained to 5 days. In cells on anodized cpTi discs, the expression level increased rapidly to 3 days, but decreased slightly in the 5-th day sample. CONCLUSION: Different surface treatments may contribute to the regulation of osteoblast function by influencing the level of gene expression of key osteogenic factors.
Durapatite ; Gene Expression ; Humans ; Osteoblasts ; Osteogenesis ; Osteosarcoma ; RNA, Messenger ; Titanium

BACKGROUND: In order to restore severely attrited teeth properly, surgical intervention in the form of a crown-lengthening procedure may be required. And also, proper diagnosis and treatment sequencing is critical to obtain a successful results. Adequate diagnostic wax-up ensures good esthetics and healthy periodontal tissue. CASE DESCRIPTION: This clinical case report describes a diagnostically based protocol for restoration on mandibular anterior teeth with crown lengthening procedure and the treatment of partially edentulous mandible combined with an edentulous maxilla. In addition, the effort to prevent the combination syndrome was described. CLINICAL IMPLICATION: An interdisciplinary diagnosis and examination through visualization of the desired results ensure conservative and more predictable outcome.
Crown Lengthening ; Crowns ; Dietary Sucrose ; Esthetics ; Humans ; Mandible ; Maxilla ; Mouth ; Mouth Rehabilitation ; Tooth

BACKGROUND: Though implant dentistry is very successful and predictable in treatment of patients with destroyed dentition, there are some cases with limitations to implant therapy. In these cases, alternative treatment modality should be considered. CASE DESCRIPTION: A patient with destroyed dentition was rehabilitated with a lateral rotational path removable partial denture. According to the diagnosis, we determined to raise vertical dimension for esthetic and functional restoration. The final restoration was performed after four months of provisional period. CLINICAL IMPLICATION: The edentulous patients with compromised esthetics and functions can be successfully treated with a rotational path removable partial denture through adequate treatment planning and precise laboratory procedure.
Dentistry ; Dentition ; Denture, Partial, Removable ; Esthetics ; Humans ; Mouth ; Mouth Rehabilitation ; Tooth Attrition ; Vertical Dimension

Nowadays, digital dentistry is generally applied to prosthodontics with fabrication of inlays or any other fixed prostheses by utilizing CAD/CAM (computer-aided design/computer-aided manufacturing) technology and intraoral scanner. However, in fabricating removable prosthesis, there are some limitations for digital technology to substitute conventional casting method. Therefore, approaching removable prostheses fabrication with CAD/CAM technology would be a meaningful trial. In this case report, Kennedy class III mandibular edentulous patient who was in need of increasing the vertical dimension of occlusion was treated with removable partial denture using CAD and rapid prototyping technique. Surveying and designing the metal framework of the partial denture was performed with CAD, and sacrificial plastic pattern was fabricated with rapid prototyping technique. During the follow up period of nine months, the removable partial denture has provided satisfactory results in esthetics and function.
Computer-Aided Design* ; Dentistry ; Denture, Partial ; Denture, Partial, Removable ; Esthetics ; Follow-Up Studies ; Humans ; Inlays ; Methods ; Plastics ; Prostheses and Implants ; Prosthodontics ; Vertical Dimension

PURPOSE: To date most of finite element analysis assumed the presence of 100% contact between bone and implant, which is inconsistent with clinical reality. In human retrieval study bone-implant contact (BIC) ratio ranged from 20 to 80%. The objective of this study was to explore the influence of bone-implant contact pattern on bone of the interface using nonlinear 3-dimensional finite element analysis. MATERIALS AND METHODS: A computer tomography-based finite element models with two types of implant (Mark III Branemark(R), Inplant(R)) which placed in the maxillary 2nd premolar area were constructed. Two different degrees of bone-implant contact ratio (40, 70%) each implant design were simulated. 5 finite element models were constructed each bone-implant contact ratio and implant design, and sum of models was 40. The position of bone-implant contact was determined according to random shuffle method. Elements of bone-implant contact in group W (wholly randomized osseointegration) was randomly selected in terms of total implant length including cortical and cancellous bone, while ones in group S (segmentally randomized osseointegration) was randomly selected each 0.75 mm vertically and horizontally. RESULTS: Maximum von Mises strain between group W and group S was not significantly different regardless of bone-implant contact ratio and implant design (P=.939). Peak von Mises strain of 40% BIC was significantly lower than one of 70% BIC (P=.007). There was no significant difference between Mark III Branemark(R) and Inplant(R) in 40% BIC, while average of peak von Mises strain for Inplant(R) was significantly lower (4886 +/- 1034 microm/m) compared with MK III Branemark(R) (7134 +/- 1232 microm/m) in BIC 70% (P<.0001). CONCLUSION: Assuming bone-implant contact in finite element method, whether the contact elements in bone were wholly randomly or segmentally randomly selected using random shuffle method, both methods could be effective to be no significant difference regardless of sample size.
Bicuspid ; Finite Element Analysis ; Humans ; Nitrogen Mustard Compounds ; Sample Size ; Sprains and Strains

PURPOSE: To evaluate the axial displacement of implant-abutment assembly after cyclic loading in internal tapered connection system. MATERIALS AND METHODS: External butt-joint connection implant and internal tapered connection implant were connected with three types of abutment for cement-retained prostheses, i.e. external type abutment (Ext group), internal tapered 1-piece abutment (Int-1 group), and internal tapered 2-piece abutment (Int-2 group). For each group, 7 implants and abutments were used. The implantabutments assemblies were clamped into the implant holder for vertical loads. A dynamic cyclic loading was applied for 150 +/- 10 N at a frequency of 4 Hz. The amount of axial displacement of the abutment into the implant was calculated at each cycle of 0, 5, 10, 50, 100, 1,000, 5,000, and 10,000. A repeated measures analysis of variance (ANOVA) for the overall effect of cyclic loading and the pattern analysis by linear mixed model were used for statistical analysis. Differences at P<.05 were considered statistically significant. RESULTS: The mean axial displacement after 10,000 cycles were 0.714 +/- 0.488 microm in Ext group, 5.286 +/- 1.604 microm in Int-1 group, and 11.429 +/- 1.902 microm in Int-2 group. In the pattern analysis, Int-1 and Int-2 group showed continuous axial displacement at 10,000 cycles. There was no declining pattern of axial displacement in the Ext group. CONCLUSION: The pattern of linear mixed model in Ext group showed no axial displacement. There were continuous axial displacements in abutment-implant assemblies in the Int-1 and Int-2 group at 10,000 cycles. More axial displacement was found in Int-2 group than in Int-1 group.
Dental Implant-Abutment Design ; Pilot Projects* ; Prostheses and Implants*

PURPOSE: The purpose of present study is to examine the correlation between the accuracy of abutment preparation and the marginal adaptation of metal coping. With this view, this study compared the correlations regard to the three different manufacturing methods of selective laser sintering technique, milling and casting. MATERIALS AND METHODS: Two master models were made in a different way. First model with deep chamfer margin was prepared directly by a general clinician and the second model was designed by 3-D designing software program with the same abutment preparation principle and produced by computer aided manufacturing. 12 Co-Cr alloy copings were produced respectively with three different method; SLS system, CAD/CAM milling and conventional lost wax technique from each master model. The total 72 copings fully sit on the master model were stereoscopically evaluated at 40 points along the entire circumferential margin. RESULTS: Significant differences in the absolute marginal discrepancies of Co-Cr copings from SLS system (P=.0231) and casting method (P<.0001) were shown between hand preparation model and computer designed model. However, no significant difference was found between the two model groups from milling method (P=.9962). CONCLUSION: Within the limitation of this study, the effect of the accuracy of abutment preparation on the marginal adaptation of Co-Cr coping is statistically significant in SLS system and casting group. The copings produced by SLS system exhibited the lowest marginal discrepancies among all groups, and the marginal gap of this method group was influenced by the accuracy of the abutment preparation.
Alloys* ; Computer-Aided Design ; Dental Abutments ; Hand ; Tooth Preparation* ; Tooth*

STATEMENT OF PROBLEM: In the partially edentulous patients, removable partial dentures have been working as a important treatment modality. Clasps, a kind of direct retainers, received some amount of stresses during the insertion and removal of partial denture on the abutment tooth. PURPOSE: The study is to investigate stresses of the different clasps. MATERIAL AND METHODS: In order to investigate the degree of stresses, maxillary partial edentulism (Kennedy Class II, modification 1) was assumed and removable partial dentures were designed on it with three kinds of metallic materials; cobalt-chromium alloy, type IV gold alloy and commercially pure (c.p.) titanium. Aker's clasp was applied on the left second molar, RPA (mesial rest-proximal plate-Aker's) clasp was on the left first premolar and wrought wire clasp was on the right first premolar. Three dimensional, non-linear, dynamic finite element analysis method was run to solve this process. RESULTS: 1. Cobalt-chromium alloy had the highest von Mises stress value and c.p. titanium had the lowest one irrespective of the types of clasps. 2. In the Aker's clasps, stress on the retentive tips was shown shortly after the appearance of stresses of the middle and minor connector areas. These time lag was much shorter in the RPA clasps than in the Aker's clasp. 3. In general, retentive tips of wrought wire clasps had much less amount of stress than other clasps. CONCLUSION: The amount of stress was the highest in the RPA clasp and the lowest in the wrought wire clasp, in general.
Alloys ; Bicuspid ; Denture, Partial ; Denture, Partial, Removable* ; Finite Element Analysis ; Humans ; Molar ; Titanium ; Tooth

STATEMENT OF PROBLEM: Unreasonable distal cantilevered implant-supported prosthesis can mask functional problems of reconstruction temporarily, but it can cause serious strain and stress around its supported implant and surrounding alveolar bone. PURPOSE: The purpose of this study was to evaluate strain of implants supporting distal cantilevered fixed prosthesis with two different cantilevered length under distal cantilevered static load. MATERIAL AND METHODS: A partially edentulous mandibular test model was fabricated with auto-polymerizing resin (POLYUROCK; Metalor technologies, Stuttgart, Swiss) and artificial denture teeth (Endura; Shofu inc., Kyoto, Japan). Two implants-supported 5-unit screwretained cantilevered fixed prosthesis was made using standard methods with Type III gold alloy (Harmony C & B55; Ivoclar-vivadent, Liechtenstein, Germany) for superstructure and reinforced hard resin (Tescera; Ivoclar-vivadent, Liechtenstein, Germany) for occlusal material. Two strain gauges (KFG-1-120-C1-11L1M2R; KYOWA electronic instruments, Tokyo, Japan) were then attached to the mesial and the distal surface of each standard abutment with adhesive (M-bond 200; Tokuyama, Tokyo, Japan). Total four strain gauges were attached to test model and connected to dynamic signal conditioning strain amplifier (CTA1000; Curiotech inc., Paju, Korea). The stepped 20-100 N in 25 N increments, cantilevered static load 8mm apart (Group I) or 16mm apart (Group II), were applied using digital push-pull gauge (Push-Pull Scale & Digital Force Gauge, Axis inc., Seoul, Korea). Each step was performed ten times and every strain signal was monitored and recorded. RESULTS: In case of Group I, the strain values were surveyed by 80.7 ~ 353.8 micrometer/m in Ch1, 7.5 ~ 47.9 micrometer/m in Ch2, 45.7 ~ 278.6 micrometer/m in Ch3 and -212.2 ~ -718.7 micrometer/m in Ch4 depending on increasing cantilevered static load. On the other hand, the strain values of Group II were surveyed by 149.9 ~ 612.8 micrometer/m in Ch1, 26.0 ~ 168.5 micrometer/m in Ch2, 114.3 ~ 632.3 micrometer/m in Ch3, and -323.2 ~ -894.7 micrometer/m in Ch4. CONCLUSION: A comparative statistical analysis using paired sample t-test about Group I Vs Group II under distal cantilevered load shows that there are statistical significant differences for all 4 channels (P<0.05).
Adhesives ; Alloys ; Axis, Cervical Vertebra ; Dentures ; Hand ; Liechtenstein ; Masks ; Prostheses and Implants* ; Seoul ; Tooth

PURPOSE: This study investigated the influence of bone quality and surgical technique on the implant stability quotient (ISQ) value. In addition, the influence of interfacial bone quality, directly surrounding the implant fixture, on the resonance frequency of the structure was also evaluated by the finite element analysis. MATERIALS AND METHODS: Two different types of bone (type 1 and type 2) were extracted and trimmed from pig rib bone. In each type of bone, the same implants were installed in three different ways: (1) Compaction, (2) Self-tapping, and (3) Tapping. The ISQ value was measured and analyzed to evaluate the influence of bone quality and surgical technique on the implant primary stability. For finite element analysis, a three dimensional implant fixture-bone structure was designed and the fundamental resonance frequency of the structure was measured with three different density of interfacial bone surrounding the implant fixture. RESULTS: In each group, the ISQ values were higher in type 1 bone than those in type 2 bone. Among three different insertion methods, the Tapping group showed the lowest ISQ value in both type 1 and type 2 bones. In both bone types, the Compaction groups showed slightly higher mean ISQ values than the Self-tapping groups, but the differences were not statistically significant. Increased interfacial bone density raised the resonance frequency value in the finite element analysis. CONCLUSION: Both bone quality and surgical technique have influence on the implant primary stability, and resonance frequency has a positive relation with the density of implant fixture-surrounding bone.
Bone Density ; Finite Element Analysis ; Ribs