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1.
Int J Oral Maxillofac Implants ; 34(1): 61­67, 2019.
Article in English | MEDLINE | ID: mdl-30521652

ABSTRACT

PURPOSE: The design and surface features of dental implants substantially affect the healing and remodeling of adjacent bones. This study aimed to investigate the impact of design and surface on bone regeneration using implants of two different pitches, each with three different surface features. MATERIALS AND METHODS: Custom-manufactured titanium implants (length, 10 mm; diameter, 3.5 mm) were divided along the major axis into two sections: one with 0.6-mm pitch and the other with 0.4-mm pitch. They were processed by turned, blasting and etching, and anodic oxidation surface treatments and implanted into rabbit tibia. The upper 4 mm of the inserted implants was exposed, and bone regeneration was induced around the exposed area using a titanium chamber (height: 4 mm) containing particulate autogenous and bovine bone. After a 12-week healing period, the quantity and quality of bone regeneration around the implants were evaluated. Thirty specimens-10 specimens each from the turned, blasting and etching, and anodic oxidation surface groups with 0.6- and 0.4-mm pitch sizes- were evaluated by histomophometric analysis. RESULTS: The vertical height and width of regenerated bone around blasting and etching and anodic oxidation surfaces were significantly greater than those around turned implants (P < .05); the vertical heights of regenerated bone around the 0.4-mm-pitch sections of blasting and etching and anodic oxidation surfaces were significantly greater than those around the 0.6-mm-pitch sections (P < .05). Both blasting and etching and anodic oxidation surfaces exhibited significantly greater bone-to-implant contact and bone volume at the implant thread than turned implants (P < .05). However, there was no significant difference between the 0.6- and 0.4-mm-pitch sections. CONCLUSION: The findings of this study indicate that blasting and etching and anodic oxidation surfaces with a 0.4-mm-pitch design result in greater vertical ingrowth of regenerated bone than those with a 0.6-mm-pitch design.


Subject(s)
Bone Regeneration/physiology , Dental Implants , Dental Prosthesis Design , Osseointegration , Titanium/chemistry , Animals , Cattle , Models, Animal , Rabbits , Surface Properties , Tibia/pathology , Tibia/surgery
2.
Int J Oral Maxillofac Implants ; 31(3): 657-64, 2016.
Article in English | MEDLINE | ID: mdl-27183075

ABSTRACT

PURPOSE: The purpose of this prospective study was to assess the change of marginal bone level around three different types of external-hex implants after 5 years using radiography. MATERIALS AND METHODS: Included in this study were 54 patients randomly put into three different groups; rough-surface implants (Brånemark), machined coronal aspect implants (Restore), and microthreaded coronal aspect implants (Hexplant). Clinical and radiographic assessments were performed contemporaneously with implant loading (baseline) and at 1, 3, and 5 years post-functional loading. A mixed-model analysis was employed to examine mean marginal bone change significance in the three treatment groups. RESULTS: In a total of 31 out of 54 patients, 81 of 135 implants remained to the end of the study. At 5 years, the microthreaded coronal aspect implants had 0.61 ± 0.32 mm mean crestal bone loss; the rough-surface implants without microthread, 0.99 ± 0.38 mm; and the machined coronal aspect implants, 1.06 ± 0.39 mm. The rough-surface implants and the machined coronal aspect implants did not exhibit statistically significantly different marginal bone loss, whereas the microthreaded coronal aspect implants exhibited significantly less marginal bone loss (P = .0015). CONCLUSION: In this research, rough-surface implants with microthreads showed positive long-term effects in preserving peri-implant bone level against functional loads when compared with implants lacking these aspects at the coronal part. Most of the bone loss was shown within 1 year of loading, and all types of implants stabilized after 1 year.


Subject(s)
Alveolar Bone Loss/pathology , Dental Implantation, Endosseous/methods , Dental Implants , Dental Prosthesis Design , Adult , Aged , Alveolar Bone Loss/diagnostic imaging , Alveolar Process/pathology , Alveolar Process/surgery , Dental Implantation, Endosseous/adverse effects , Female , Follow-Up Studies , Humans , Male , Mandible/diagnostic imaging , Mandible/surgery , Middle Aged , Prospective Studies , Surface Properties
3.
J Prosthodont ; 23(7): 534-9, 2014 Oct.
Article in English | MEDLINE | ID: mdl-24750340

ABSTRACT

PURPOSE: The objective of this study was to evaluate the influence of coping design modifications on maximum first principal stress (MPS) in a mathematical zirconia ceramic crown model. MATERIALS AND METHODS: For a nonlinear, 3D finite element analysis, a simplified tooth model was built on the basis of the average dimensions of mandibular second molars. Virtual tooth reduction was performed to model an abutment with a flat occlusal surface and 16° convergence angle between facing walls. The cement layer was set to a thickness of 100 µm. Three different copings-one with 0.5-mm constant thickness; one with constant thickness and extended lingual and proximal collars; and a novel design with zirconia beam reinforcement-were designed to simulate zirconia ceramic restorations. The novel design had strategically positioned zirconia beams on the lingual and marginal ridges to protect veneer ceramics, and was divided into three subdesigns according to the width of the zirconia beam (0.5, 0.8, and 1 mm). Combinations of vertical and horizontal load were applied over the distolingual marginal ridge, and the MPSs were evaluated. RESULTS: The novel design showed the lowest MPS in veneer ceramics under most loading conditions. The only exception to this was the novel design with a 0.5-mm zirconia beam width under mesial horizontal load. CONCLUSIONS: Compared to constant thickness coping with or without extended collars, the novel coping design reduced MPS in veneer ceramics; however, narrow zirconia beams should be avoided to prevent elevations in MPS in veneer ceramic layers.


Subject(s)
Ceramics/chemistry , Crowns , Dental Materials/chemistry , Dental Prosthesis Design , Yttrium/chemistry , Zirconium/chemistry , Bite Force , Computer-Aided Design , Dental Abutments , Dental Veneers , Finite Element Analysis , Humans , Imaging, Three-Dimensional/methods , Materials Testing , Nonlinear Dynamics , Resin Cements/chemistry , Stress, Mechanical , Surface Properties , User-Computer Interface
4.
Int J Oral Maxillofac Implants ; 28(1): 57-66, 2013.
Article in English | MEDLINE | ID: mdl-23377048

ABSTRACT

PURPOSE: After placement, titanium dental implants are conditioned by blood and tissue fluid. These initial processes are affected by the hydrophilicity of the implant. The hydrophilicity of titanium dioxide (TiO2) can be increased by ultraviolet (UV)-C irradiation. Anodic oxidation is an electrochemical treatment used to form TiO2 layers that are characterized by their thickness, roughness, and porosity on the surface of titanium implants. These oxide layers increase implant durability and performance. Therefore, the aim of this study was to investigate the effect of UV-C irradiation on the anodized titanium surface and the resultant tissue response. MATERIALS AND METHODS: Twenty-five titanium disks and 56 screw-type implants were fabricated of commercially pure titanium and anodized. The samples were divided into a control group (anodized) and a test group (anodized and UV-C irradiated with a bactericidal UV sterilizer for 24 hours just prior to experimentation). The surface characteristics of the disks, including roughness, crystal phase of the oxide layer, chemical composition, and water contact angle, were then evaluated. Implants were placed into rabbit tibiae, and histomorphometric analysis was performed after healing periods of 4 and 12 weeks. The results were compared between groups. RESULTS: The surface topography and phase of the oxide layer were not significantly different between test and control groups. Carbon surface impurities were noticeably decreased after UV-C irradiation, and water contact angle measurements were significantly lower (P < .001). After a healing period of 4 weeks, test implants showed higher values for both bone-to-implant contact and the amount of bone in the thread area of the implant (P < .01). No significant differences between groups were found for either histomorphometric measurement after 12 weeks. CONCLUSIONS: UV-C irradiation of an anodized titanium implant, accomplished via a bactericidal UV sterilizer, promoted an early bone response in rabbit tibiae.


Subject(s)
Hydrophobic and Hydrophilic Interactions/radiation effects , Osseointegration , Sterilization/instrumentation , Titanium/radiation effects , Ultraviolet Rays , Wound Healing , Animals , Dental Implantation/methods , Dental Implants , Rabbits , Surface Properties/radiation effects , Tibia/pathology , Titanium/chemistry , Titanium/therapeutic use
5.
Int J Oral Maxillofac Implants ; 27(6): 1389-99, 2012.
Article in English | MEDLINE | ID: mdl-23189288

ABSTRACT

PURPOSE: This study compared the bone regeneration response of different bone graft materials inside canals within anodized titanium implants in cortical and cancellous bone. MATERIALS AND METHODS: Upper and lower transverse canals were created in anodic oxidized-surface titanium implants to serve as sites for cortical and cancellous bone regeneration, respectively. The canals were filled with bone graft materials--rabbit bone marrow--derived mesenchymal stem cells and platelet-rich plasma, xenograft, or alloplast (micromacroporous biphasic calcium phosphate)-or left empty (as a control). Eighty implants were surgically placed into the tibiae of 20 New Zealand white rabbits. After 4 and 12 weeks of healing, histomorphometric analysis was performed to measure the newly formed bone areas (NBs) inside the canals. RESULTS: Inside the upper canals, the bone graft groups provided significantly higher NBs than the control (no graft). However, there was no significant difference in NBs between the bone graft groups. Inside the lower canals, no significant difference in NBs was shown among the all groups. The NBs inside the upper canals were significantly greater than those inside the lower canals in all groups after 4 and 12 weeks, respectively. CONCLUSIONS: In the cortical bone, there was significant difference in bone regeneration between the control and the bone graft groups. However, there was no significant difference among the bone graft groups in cortical and cancellous bone regeneration. There was significant difference in bone regeneration between the cortical and cancellous bone regions in the all groups using the titanium canal model.


Subject(s)
Bone Regeneration , Ceramics/therapeutic use , Hydroxyapatites/administration & dosage , Mesenchymal Stem Cell Transplantation/methods , Platelet-Rich Plasma , Animals , Bone Marrow Cells , Bone Transplantation , Dental Pins , Rabbits , Tibia , Time Factors , Titanium , Transplantation, Heterologous , Wound Healing
6.
J Dent ; 40(10): 866-72, 2012 Oct.
Article in English | MEDLINE | ID: mdl-22819954

ABSTRACT

OBJECTIVES: The purpose of this study was to evaluate the influence of internal-gap width and cement type on the retentive force of zirconia copings. METHODS: A CAD/CAM system was used to mill 48 identical abutments on extracted human molars and fabricate 48 zirconia copings. The internal-gap width for cement was set to 40 µm or 160 µm (n=24 each). Three cement types (Panavia F, RelyX Unicem, and RelyX Luting) were used with each internal-gap width (n=8/cement type). The intaglio surfaces of the copings were airborne-particle abraded, and each coping was cemented onto the corresponding abutment using the indicated luting agent. After 10,000 cycles of thermocycling, the retentive force was evaluated by pullout tests. Kruskal-Wallis and Wilcoxon Rank Sum tests were used for data analysis (α=0.05). RESULTS: In the 40-µm gap groups, Panavia F had the highest mean retentive force compared to RelyX Unicem and RelyX Luting (P<0.000). In 160-µm gap groups, RelyX Unicem had the highest mean retentive force compared to Panavia F and RelyX Luting (P<0.000). CONCLUSIONS: With the increase in internal gap width, a resin cement with self-etching agents as a co-initiator for autopolymerization resulted in significantly decreased retentive force, whereas a resin-modified glass ionomer cement or a self-adhesive resin cement did not. Use of resin cements rather than resin-modified glass ionomer cements improved the retentive force of zirconia copings regardless of the amount of internal gap width.


Subject(s)
Crowns , Dental Cements/chemistry , Dental Marginal Adaptation , Dental Materials/chemistry , Dental Prosthesis Retention , Zirconium/chemistry , Cementation/methods , Composite Resins/chemistry , Computer-Aided Design , Dental Abutments , Dental Etching/methods , Dental Prosthesis Design , Dental Stress Analysis/instrumentation , Glass Ionomer Cements/chemistry , Humans , Materials Testing , Microscopy, Electron, Scanning , Resin Cements/chemistry , Stress, Mechanical , Surface Properties , Temperature , Time Factors , Tooth Preparation/methods
7.
Int J Oral Maxillofac Implants ; 27(2): 265-72, 2012.
Article in English | MEDLINE | ID: mdl-22442763

ABSTRACT

PURPOSE: Although the laser has become one of the most commonly used tools for implant dentistry, research is lacking on whether or not the laser causes any changes on the surface of titanium (Ti) implants. The present study analyzed the morphology, composition, crystal structure, and surface roughness changes of machined and anodized Ti surfaces, irradiated with erbium chromium-doped yttrium-scandium-gallium-garnet (Er,Cr:YSGG), erbium-doped yttrium-aluminum-garnet (Er:YAG), and carbon dioxide (CO2) lasers. MATERIALS AND METHODS: Seventy-two Ti disks were fabricated by machining commercially pure Ti (grade 3); 36 of them were anodized at 300 V. The disks were irradiated with Er,Cr:YSGG, Er:YAG, and CO2 lasers at five different powers (1, 2, 3, 4, and 5 W). The irradiated disks were examined with scanning electron microscopy, electron probe microanalysis, x-ray diffractometry, and optical interferometry. RESULTS: Surface changes were observed on both types of Ti surfaces irradiated with the Er,Cr:YSGG laser when more than 3 W of power were applied. Surface changes were observed on both types of Ti surfaces when irradiated with the Er:YAG laser with more than 2 W of power. No change was observed when the disks were irradiated with the CO2 laser. The proportion of oxide in the machined Ti disk increased after the application of the Er,Cr:YSGG or Er:YAG laser. In the anodized Ti disk, the anatase peak intensity decreased and the rutile peak intensity increased after laser irradiation. The irradiated Ti disks were significantly rougher than the nonirradiated Ti disks. CONCLUSIONS: The Er:YAG and Er,Cr:YSGG laser resulted in surface changes on the Ti disks according to the power output. The CO2 laser did not affect the surface of the Ti disks, irrespective of the power output.


Subject(s)
Dental Materials/radiation effects , Lasers, Gas , Lasers, Solid-State , Titanium/radiation effects , Calcium/analysis , Carbon/analysis , Crystallography , Dental Materials/chemistry , Electrochemical Techniques , Electron Probe Microanalysis , Humans , Interferometry , Light , Materials Testing , Microscopy, Electron, Scanning , Nitrogen/analysis , Oxidation-Reduction , Oxygen/analysis , Phosphorus/analysis , Radiation Dosage , Surface Properties , Time Factors , Titanium/analysis , Titanium/chemistry , X-Ray Diffraction
8.
J Adv Prosthodont ; 3(3): 119-25, 2011 Sep.
Article in English | MEDLINE | ID: mdl-22053241

ABSTRACT

PURPOSE: The aim of this study was to evaluate the influence of resin cement thickness on the microtensile bond strength between zirconium-oxide ceramic and resin cement. MATERIALS AND METHODS: Thirty-two freshly extracted molars were transversely sectioned at the deep dentin level and bonded to air-abraded zirconium oxide ceramic disks. The specimens were divided into 8 groups based on the experimental conditions (cement type: Rely X UniCem or Panavia F 2.0, cement thickness: 40 or 160 µm, storage: thermocycled or not). They were cut into microbeams and stored in 37℃ distilled water for 24 h. Microbeams of non-thermocycled specimens were submitted to a microtensile test, whereas those of thermocycled groups were thermally cycled for 18,000 times immediately before the microtensile test. Three-way ANOVA and Sheffe's post hoc tests were used for statistical analysis (α=95%). RESULTS: All failures occurred at the resin-zirconia interface. Thermocycled groups showed lower microtensile bond strength than non-thermocycled groups (P<.001). Differences in cement thickness did not influence the resin-zirconia microtensile bond strength given the same resin cement or storage conditions (P>.05). The number of adhesive failures increased after thermocycling in all experimental conditions. No cohesive failure was observed in any experimental group. CONCLUSION: When resin cements of adhesive monomers are applied over air-abraded zirconia restorations, the degree of fit does not influence the resin-zirconia microtensile bond strength.

9.
J Prosthet Dent ; 105(6): 367-73, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21640237

ABSTRACT

STATEMENT OF PROBLEM: Implant impressions without impression copings can be used for cement-retained implant restorations. A comparison of the accuracy of implant impressions with and without impression copings is needed. PURPOSE: The purpose of this study was to evaluate and compare the dimensional accuracy of implant definitive casts that are fabricated by implant impressions with and without impression copings. MATERIAL AND METHODS: An acrylic resin maxillary model was fabricated, and 3 implant replicas were secured in the right second premolar, first, and second molars. Two impression techniques were used to fabricate definitive casts (n=10). For the coping group (Group C), open tray impression copings were used for the final impressions. For the no-coping group (Group NC), cementable abutments were connected to the implant replicas, and final impressions were made assuming the abutments were prepared teeth. Computerized calculation of the centroids and long axes of the implant or stone abutment replicas was performed. The Mann-Whitney U test analyzed the amount of linear and rotational distortion between groups (α =.05). RESULTS: At the first molar site, Group NC showed significantly greater linear distortion along the Y-axis, with a small difference between the groups (Group C, 7.8 ± 7.4 µm; Group NC, 19.5 ± 12.2). At the second molar site, increased distortion was noted in Group NC for every linear and rotational variable, except for linear distortion along the Z-axis. CONCLUSIONS: Implant impression with open tray impression copings produced more accurate definitive casts than those fabricated without impression copings, especially those with greater inter-abutment distance.


Subject(s)
Dental Impression Technique/instrumentation , Dental Prosthesis, Implant-Supported , Cementation , Dental Prosthesis Retention/methods , Imaging, Three-Dimensional , Maxilla , Models, Dental
10.
J Oral Implantol ; 36(5): 357-62, 2010.
Article in English | MEDLINE | ID: mdl-20545528

ABSTRACT

This study was undertaken to evaluate the effect of microthread geometry of scalloped design implant on marginal bone resorption. Four types of scalloped design titanium implant specimens were prepared. The type 1 implant had a machined scalloped collar, type 2 had a sandblasted and acid-etched scalloped collar, type 3 had horizontal microthreads, and type 4 had parabolic microthreads, which are parallel with the scalloped conical margin. Two implants of a type were randomly installed immediately after extraction in the mandible of a beagle dog. Definitive prostheses were delivered immediately after surgery. After 12 weeks of healing, the dog was sacrificed and microtomography was performed. Type 4 specimens showed a marginal bone loss pattern definitively analogous to the scalloped margin. In this preliminary study, microthread geometry affected the marginal bone resorption pattern of scalloped design implants. However, additional specimens and more controlled conditions should be applied in future studies to confirm these results.


Subject(s)
Alveolar Bone Loss/diagnostic imaging , Alveolar Bone Loss/etiology , Dental Implants/adverse effects , Dental Prosthesis Design/adverse effects , Immediate Dental Implant Loading , Animals , Dogs , Pilot Projects , Random Allocation , Surface Properties , X-Ray Microtomography
11.
Int J Oral Maxillofac Implants ; 25(2): 309-14, 2010.
Article in English | MEDLINE | ID: mdl-20369089

ABSTRACT

PURPOSE: The purpose of this study was to investigate the early tissue response around three one-piece implant systems with different transmucosal designs. MATERIALS AND METHODS: Three one-piece dental implant systems with different profiles and surface roughnesses on the transmucosal portion were examined in the current study. The transmucosal portions were flared and machined (FM), concave and machined with microgrooves (CMG), or straight and anodic oxidized (SA). A total of 30 implants (10 of each type) were placed in computer-generated randomized order in the mandibular residual ridges of five beagle dogs. Six months later, all animals were sacrificed and histologic sections were prepared to measure epithelial tissue height, connective tissue contact, and the amount of bone resorption. One-way analysis of variance and the Bonferroni post hoc test were used for statistical evaluation (alpha = 95%). RESULTS: After a 6-month nonfunctional loading period, all 30 implants were clinically immobile. Slight swelling and redness of the peri-implant soft tissue were noticed around most of the implant abutments. Histometric analysis showed that the FM implants had a longer epithelial tissue height than the CMG implants. The CMG implants showed the greatest amount of connective tissue attachment among the three groups and the least amount of marginal bone resorption. The CMG and SA implants showed bone growth above the initial reference point at 10 and 7 measurement sites, respectively, whereas no bone overgrowth was noted around the FM implants. CONCLUSION: Based on this study conducted in five beagle dogs, a concave transmucosal profile with a microgrooved surface was associated with longer connective tissue attachments and less bone resorption versus implants that were flared with a machined surface or straight with an anodic oxidized surface in the early healing phase. Int J Oral Maxillofac Implants 2010;25:309-314.


Subject(s)
Alveolar Process/anatomy & histology , Dental Implants , Dental Prosthesis Design , Gingiva/anatomy & histology , Alveolar Bone Loss/pathology , Animals , Connective Tissue/anatomy & histology , Dental Abutments , Dogs , Epithelial Attachment/anatomy & histology , Gingivitis/pathology , Mandible/surgery , Materials Testing , Osseointegration/physiology , Osteogenesis/physiology , Oxidation-Reduction , Random Allocation , Surface Properties
12.
Int J Oral Maxillofac Implants ; 24(4): 655-62, 2009.
Article in English | MEDLINE | ID: mdl-19885405

ABSTRACT

PURPOSE: The purpose of this study was to evaluate differences in the healing of cortical and cancellous bone around titanium implants with two different surfaces (machined or anodized) in rabbit tibiae. MATERIALS AND METHODS: Screw-shaped commercially pure titanium implants of two different surface types were fabricated: machined implants (control) and anodized implants; each had two transverse canals that served as sites for bone ingrowth. In the tibiae of six New Zealand white rabbits, a total of 24 implants (12 implants of each surface) were surgically placed in a randomized arrangement. The upper transverse canal was positioned in the cortical bone region, and the lower transverse canal was positioned in the cancellous bone region. After a 1-month healing period, undecalcified ground sections were subjected to histologic and histomorphometric analyses. A mixed-model analysis of variance was used to compare the two types of implants and to control for the random effect of animals. RESULTS: The percentage of bone-to-implant contact (BIC) inside the upper canals was 16.45% +/- 4.05% for controls (machined surface) and 24.85% +/- 4.86% for anodized implants. BIC inside the lower canals was 7.01% +/- 2.34% for controls and 11.35% +/- 2.67% for anodized implants. The percentage of bone area inside the upper canals was 10.94% +/- 4.06% for controls and 27.95% +/- 12.38% for anodized implants. The percentage of bone area inside the lower canals was 3.16% +/- 1.08% for controls and 4.66% +/- 1.53% for anodized implants. For all measures, the anodized implants had higher values than the controls (P < .0001). CONCLUSION: The results suggest that anodized surface modification of titanium implants is beneficial to both cortical and cancellous bone healing.


Subject(s)
Dental Implants , Dental Materials/chemistry , Tibia/pathology , Titanium/chemistry , Animals , Dental Prosthesis Design , Electrochemical Techniques , Osseointegration/physiology , Osteogenesis/physiology , Rabbits , Random Allocation , Surface Properties , Time Factors , Wound Healing/physiology
13.
J Adv Prosthodont ; 1(1): 37-40, 2009 Mar.
Article in English | MEDLINE | ID: mdl-21165253

ABSTRACT

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.

14.
J Adv Prosthodont ; 1(3): 140-4, 2009 Nov.
Article in English | MEDLINE | ID: mdl-21165270

ABSTRACT

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.

15.
Int J Oral Maxillofac Implants ; 21(6): 859-66, 2006.
Article in English | MEDLINE | ID: mdl-17190295

ABSTRACT

PURPOSE: The synergistic effect of fibroblast growth factor (FGF) and human fibronectin fragment (hFNIII9-10) on osteoblast cell adhesion has been demonstrated in vitro. The purpose of this study was to evaluate the bone response around anodized titanium implants treated with FGF-FN fusion protein using the histomorphometric analysis and the removal torque test. MATERIALS AND METHODS: Threaded implants were manufactured by machining a commercially pure titanium (grade 4). Two different groups of samples were prepared: Group 1 samples were anodized under a constant voltage of 300 V, and group 2 samples were anodized under a constant voltage of 300 V and then soaked in a solution containing fusion protein (65 microg/mL) for 24 hours. Ten implants from each group were placed in rabbit tibiae (1 implant per group per rabbit; each rabbit served as its own control). After a 3-month healing period, the animals were sacrificed. Removal torque testing and histomorphometric analysis was then carried out. RESULTS: The mean removal torque value of group 2 (44.8 Ncm) was greater than that of group 1 (37.6 Ncm). The percentages of bone-implant contact of the best 3 consecutive threads were 76.37% for group 1 and 88.02% for group 2. The percentage of bone-implant contact for the total length of the implant was higher for group 2 (36.91%) than for group 1 (29.47%). However, the percentage of the area inside the threads that consisted of bone did not differ significantly for the 2 groups. DISCUSSION AND CONCLUSION: This study demonstrated that the FGF-FN fusion protein coating on anodized implants may enhance osseointegration. However, the influence of fibronectin- and FGF-treated rough surfaces on long-term prognosis and the propagation of inflammation are subjects for further study.


Subject(s)
Coated Materials, Biocompatible/chemistry , Dental Implants , Dental Materials/chemistry , Fibroblast Growth Factors/chemistry , Fibronectins/chemistry , Osseointegration/physiology , Tibia/ultrastructure , Titanium/chemistry , Animals , Dental Prosthesis Design , Humans , Rabbits , Recombinant Fusion Proteins/chemistry , Stress, Mechanical , Surface Properties , Tibia/physiology , Torque , Wound Healing/physiology
16.
Int J Oral Maxillofac Implants ; 21(5): 747-55, 2006.
Article in English | MEDLINE | ID: mdl-17066636

ABSTRACT

PURPOSE: Four possible displacements of implant components from a patient model to a definitive cast were assessed to suggest a standard method of comparing the accuracies of implant impression techniques. MATERIALS AND METHODS: Two techniques for impression making were assessed: a nonsplinted open-tray technique and a light-curing resin splinted open-tray technique. A mandibular model with 5 parallel implants was fabricated. Five definitive casts were fabricated per technique. Using a computerized coordinate measuring machine, 5 part coordinate systems were established, and 7 sets of data were obtained for each sample. From the data, the amount of displacement while connecting components and the linear and angular displacement of components during impression making and cast fabrication were calculated. The Mann-Whitney test was used to determine significant differences between the impression techniques (P < .05). RESULTS: The average displacements while connecting impression copings and abutment replicas were 31.3 and 30.4 microm, respectively. Less displacement occurred in the nonsplinted group compared to the splinted group during impression making (P = .001) but greater displacement occurred in that group during definitive cast fabrication (P = .015). DISCUSSION: In contrast to previous studies, the current study excluded displacement resulting from component connection, because displacement from that source has no relation to impression technique and cannot be controlled. CONCLUSIONS: Connecting a component produced as great a displacement as that resulting solely from a impression or cast fabrication. The nonsplinted group was more accurate during impression making but less accurate during cast fabrication.


Subject(s)
Dental Abutments , Dental Implants , Dental Impression Technique/instrumentation , Dental Prosthesis Design , Models, Dental , Acrylic Resins , Dental Implantation, Endosseous , Humans , Mandible , Splints , Statistics, Nonparametric
17.
Int J Oral Maxillofac Implants ; 21(5): 789-94, 2006.
Article in English | MEDLINE | ID: mdl-17066642

ABSTRACT

PURPOSE: To evaluate the influence of macro- and microstructure of the implant surface at the marginal bone level after functional loading. MATERIALS AND METHODS: Sixty-eight patients were randomly assigned to 1 of 3 groups. The first group received 35 implants with a machined neck (Ankylos); the second group, 34 implants with a rough-surfaced neck (Stage 1); and the third, 38 implants with a rough-surfaced neck with microthreads (Oneplant). Clinical and radiographic examinations were conducted at baseline (implant loading) and 3, 6, and 12 months postloading. Two-way repeated analysis of variance (ANOVA) was used to test the significance of marginal bone change of each tested group at baseline, 3, 6, and 12 month follow-ups and 1-way ANOVA was also used to compare the bone loss of each time interval within the same implant group (P < .05). RESULTS: At 12 months, significant differences were noted in the amount of alveolar bone loss recorded for the 3 groups (P < .05). The group with the rough-surfaced microthreaded neck had a mean crestal bone loss of 0.18 +/- 0.16 mm; the group with the rough-surfaced neck, 0.76 +/- 0.21 mm; and the group with the machined neck, 1.32 +/- 0.27 mm. In the rough-surfaced group and the rough-surfaced microthreaded group, no statistically significant changes were observed after 3 months, whereas the machined-surface group showed significant bone loss for every interval (P < .05). DISCUSSION: To minimize marginal bone loss, in addition to the use of a rough surface at the marginal bone level, a macroscopic modification such as the addition of microthreads could be recommended. A rough surface and microthreads at the implant neck not only reduce crestal bone loss but also help with early biomechanical adaptation against loading in comparison to the machined neck design. CONCLUSION: A rough surface with microthreads at the implant neck was the most effective design to maintain the marginal bone level against functional loading.


Subject(s)
Alveolar Bone Loss/etiology , Dental Implants/adverse effects , Dental Prosthesis Design/adverse effects , Adult , Analysis of Variance , Dental Implantation, Endosseous/methods , Dental Prosthesis, Implant-Supported , Dental Stress Analysis , Female , Follow-Up Studies , Humans , Male , Surface Properties
18.
Int J Oral Maxillofac Implants ; 21(2): 195-202, 2006.
Article in English | MEDLINE | ID: mdl-16634489

ABSTRACT

PURPOSE: The purpose of this study was to investigate the effect of 3 different abutment types on the stress distribution in bone with inclined loads using finite element analysis. MATERIALS AND METHODS: The 1-body, internal-hex, and external-hex implant systems were modeled to study the effect of abutment type on stress distribution in bone. The bone model used in this study comprised compact and spongious bone assumed to be homogeneous, isotropic, and linearly elastic. RESULTS: In the case of the 1-piece implant, the load was transferred evenly not only in the implant system but also in bone. However, the maximum Von Mises stress generated in bone with the 1-piece implant was always higher than that generated with the internal-hex implant, regardless of load angle inclination. In the case of the internal-hex implant, the contact condition with friction between abutment and implant in the tapered joints and at abutment neck reduced the effect of bending caused by horizontal component of inclined load. The maximum Von Mises stress in bone was the highest for the external-hex implant. DISCUSSION: It was found that the internal-hex implant system generated the lowest maximum Von Mises stresses for all loading conditions because of reduction of the bending effect by sliding in the tapered joints between the implant and abutment. CONCLUSIONS: It was concluded that abutment type has significant influence on the stress distribution in bone because of different load transfer mechanisms and the differences in size of the contact area between the abutment and implant.


Subject(s)
Alveolar Process/physiology , Dental Abutments , Dental Implants , Dental Stress Analysis/methods , Dental Implantation, Endosseous , Dental Prosthesis Design , Elasticity , Finite Element Analysis , Humans , Models, Biological , Stress, Mechanical
19.
Article in English | MEDLINE | ID: mdl-15747671

ABSTRACT

PURPOSE: This study was undertaken to evaluate ion beam-assisted deposition (IBAD) of hydroxyapatite (HA) on the grit-blasted surface of endosseous dental implants 6 weeks postplacement. MATERIALS AND METHODS: A total of 40 implants was placed in the tibiae of 10 New Zealand white rabbits. Twenty implants were grit-blasted only and the other 20 were grit-blasted and coated with HA by the IBAD method. After 6 weeks of healing, the rabbits were sacrificed and removal torque tests, histomorphometry, and morphometric analysis of microtomographic images were performed. RESULTS: The HA-coated group showed significantly higher removal torque, bone-to-implant contact, and bone volume than the other group. DISCUSSION AND CONCLUSION: In a previous study, the authors suggested that HA coating deposited on a machined surface by the IBAD method showed results comparable to or more favorable than the results obtained with a blasted surface. This study indicated that the HA coating produced by the IBAD method was also very effective on the aluminum oxide-blasted surface, as demonstrated by the early formation of osseointegration. Morphometric analysis by microtomography showed some promise in measuring the osseointegration rate. (More than 50 references.)


Subject(s)
Coated Materials, Biocompatible , Dental Implants , Durapatite , Implants, Experimental , Osseointegration , Animals , Bone Density , Dental Etching , Dental Implantation, Endosseous , Device Removal , Durapatite/pharmacology , Female , Ions , Microradiography , Osseointegration/drug effects , Rabbits , Surface Properties , Tibia , Titanium , Torque
20.
Article in English | MEDLINE | ID: mdl-15472663

ABSTRACT

OBJECTIVE: We developed a new program for digital subtraction radiography (DSR) having useful functions to get the DSR image more accurately and efficiently. The purpose of this study was to evaluate the accuracy of the DSR image acquired using the new program as compared with the ready-made program. STUDY DESIGN: Four observers performed the DSR process using our program and the ready-made program for digital intraoral radiographs taken from incisor, premolar, and molar regions. The statistical difference was evaluated between the programs, between the observers, and between the regions. RESULTS: The DSR image using our program was superior to that with the ready-made program in all the observers and all the radiographed regions. Also, there was the statistical difference among the observers, especially in our program. CONCLUSION: The DSR image using the new program was very accurate compared with ready-made program, so the program was useful to get an accurate DSR image.


Subject(s)
Radiography, Dental, Digital/methods , Software/standards , Subtraction Technique , Humans , Observer Variation , Radiographic Image Enhancement/methods
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