Analysis of Removal Torque of Injection Molded Zirconia Implants; An Experimental Study on Beagles.

This study compared the removal torque between injection molded zirconia implants and titanium implants with resorbable blast media (RBM) surfaces in beagle humeri. Fifteen screw-shaped implants were classified into 3 groups; titanium implant with RBM surface (Group RT), injection molded zirconia implant (Group Zr) and injection molded zirconia implant with sand-blasted surface (Group ZrS). Implants were inserted into beagle humeri. After 12 weeks, removal torque values were measured. The Zr group has a slightly higher removal torque value than the RT and ZrS groups but there were no significant differences among groups. Zirconia implants shows a similar removal torque to RBM titanium implants. This in vivo study showed injection molded zirconia implants could be an alternative to RBM titanium implants in terms of removal torque.

Shore hardness and tensile bond strength of long-term soft denture lining materials.

STATEMENT OF PROBLEM: Reduced softness and separation from the denture base are the most significant problems of long-term soft lining materials. PURPOSE: The purpose of this study was to evaluate the durometer Shore A hardness and tensile bond strength of long-term soft denture lining materials and to investigate the correlation between these 2 properties. MATERIAL AND METHODS: A group of 7 soft lining materials, 6 silicone based (Dentusil, GC Reline Soft, GC Reline Ultrasoft, Mucopren Soft, Mucosoft, Sofreliner Tough) and 1 acrylic resin based (Durabase), were evaluated for durometer Shore A hardness and tensile bond strength to heat-polymerized denture base resin (Lucitone 199). A specially designed split mold and loading assembly with a swivel connector were used for the durometer Shore A hardness test and tensile bond strength test to improve accuracy and facilitate measurement. Three specimens of each product were stored in a 37°C water bath, and durometer Shore A hardness tests were carried out after 24 hours and 28 days. A tensile bond strength test was carried out for 10 specimens of each product, which were stored in a 37°C water bath for 24 hours before the test. Repeated-measures ANOVA, the Kruskal-Wallis and Duncan multiple range tests, and the Spearman correlation were used for statistical analyses. RESULTS: The repeated-measures ANOVA found significant durometer Shore A hardness differences for the materials (P<.001) and the interaction effect (aging×materials) (P<.001). GC Reline Ultrasoft showed the lowest mean durometer Shore A hardness (21.30 ±0.29 for 24 hours, 34.73 ±0.47 for 28 days), and GC Reline Soft showed the highest mean durometer Shore A hardness (50.13 ±0.48 for 24 hours, 57.20 ±0.28 for 28 days). The Kruskal-Wallis test found a significant difference in the mean tensile bond strength values (P<.001). GC Reline Ultrasoft (0.82 ±0.32 MPa) and Mucopren Soft (0.96 ±0.46 MPa) had a significantly lower mean tensile bond strength (P<.05). GC Reline Soft had the highest mean tensile bond strength (2.99 ±0.43 MPa) (P<.05), and acrylic resin-based Durabase showed a significantly different tensile bond strength (1.32 ±0.16 MPa), except for Mucopren Soft, among the materials (P<.05). The tensile bond strength and Shore A hardness showed a statistically insignificant moderate positive correlation (r=0.571, P=.180 for Shore A hardness 24 hours versus tensile bond strength; r=0.607, P=.148 for Shore A hardness 28 days versus tensile bond strength). CONCLUSIONS: Within the limitations of this study, significant differences were found in durometer Shore A hardness (with aging time) and tensile bond strength among the materials. Adhesive failure was moderately correlated with durometer Shore A hardness, especially after 28 days, but was not significant.

Titanium dioxide nanotube modified implants: an animal study on bone formation.

This study examined the bone response to titanium dioxide nanotube modified implants. A total of 24 implants were placed in the femur of 4 beagles. Before placement, screw-shaped implants were classified into 3 groups; machined surface (group M), titanium dioxide nanotube modification of the machined surface (group MN) and titanium dioxide nanotube modification of the RBM surface (group RN). The texture morphology was observed via scanning electron microscopy. Animals were euthanized after 4 and 12 weeks of submerged healing and the histologic and histomorphometric analyses were performed. Groups MN and RN showed a significantly higher percentage of mineralized bone than that in group M (p < 0.05). The results of this in vivo study constitute significant evidence that the presence of the titanium dioxide nanotubes enhance osseointegration of implants.

Marginal accuracy and internal fit of machine-milled and cast titanium crowns.

STATEMENT OF PROBLEM: Titanium is an alternative tooth restorative material because of a its biocompatibility and mechanical properties. However, there is little information on the marginal accuracy of a complete titanium crown with different margin configurations. PURPOSE: This study examined the effect of fabrication method and margin configuration on the marginal and internal fit of complete titanium crowns. MATERIAL AND METHODS: An acrylic resin maxillary first molar was prepared with shoulder (buccal), chamfer (palatal), and knife edge (proximal) margin configurations. Forty crowns were produced and then divided into 2 groups according to the manufacturing method (casting method or CAD/CAM technique) (n=20). Each crown was luted to the original stone die with zinc phosphate cement. The margin of the crown, center point of the axial wall, and occlusal area were measured with a 3-dimensional measuring microscope. An independent t-test (internal gap) and repeated measures 2-way ANOVA (marginal gap) were used for statistical analysis (α=.05). RESULTS: The mean marginal gap of the cast group was significantly smaller than that of the CAD/CAM group (P<.001). The margin configuration affected the measured marginal discrepancy (P<.001). In both groups, the mean marginal gap of the chamfer and shoulder margin was significantly smaller than that of the knife-edge margin (P<.001). CONCLUSIONS: Castings-produced titanium crowns with a better marginal fit than the CAD/CAM technique. The knife-edge margin exhibited the greatest marginal discrepancy.

Comparison of different impression techniques for edentulous jaws using three-dimensional analysis.

PURPOSE: The purpose of this study was to compare two novel impression methods and a conventional impression method for edentulous jaws using 3-dimensional (3D) analysis software. MATERIALS AND METHODS: Five edentulous patients (four men and one woman; mean age: 62.7 years) were included. Three impression techniques were used: conventional impression method (CI; control), simple modified closed-mouth impression method with a novel tray (SI), and digital impression method using an intraoral scanner (DI). Subsequently, a gypsum model was made, scanned, and superimposed using 3D analysis software. Mean area displacement was measured using CI method to evaluate differences in the impression surfaces as compared to those values obtained using SI and DI methods. The values were confirmed at two to five areas to determine the differences. CI and SI were compared at all areas, while CI and DI were compared at the supporting areas. Kruskal-Wallis test was performed for all data. Statistical significance was considered at P value <.05. RESULTS: In the comparison of the CI and SI methods, the greatest difference was observed in the mandibular vestibule without statistical significance (P>.05); the difference was < 0.14 mm in the maxilla. The difference in the edentulous supporting areas between the CI and DI methods was not significant (P>.05). CONCLUSION: The CI, SI, and DI methods were effective in making impressions of the supporting areas in edentulous patients. The SI method showed clinically applicability.

Effect of ferrule on the fracture resistance of mandibular premolars with prefabricated posts and cores.

PURPOSE: This study evaluated fracture resistance with regard to ferrule lengths and post reinforcement on endodontically treated mandibular premolars incorporating a prefabricated post and resin core. MATERIALS AND METHODS: One hundred extracted mandibular premolars were randomly divided into 5 groups (n=20): intact teeth (NR); endodontically treated teeth (ETT) without post (NP); ETT restored with a prefabricated post with ferrule lengths of either 0 mm (F0), 1 mm (F1), or 2 mm (F2). Prepared teeth were restored with metal crowns. A thermal cycling test was performed for 1,000 cycles. Loading was applied at an angle of 135 degrees to the axis of the tooth using a universal testing machine with a crosshead speed of 2.54 mm/min. Fracture loads were analyzed by one-way ANOVA and Tukey HSD test using a statistical program (α=.05). RESULTS: There were statistical differences in fracture loads among groups (P<.001). The fracture load of F2 (237.7 ± 83.4) was significantly higher than those of NP (155.6 ± 74.3 N), F0 (98.8 ± 43.3 N), and F1 (152.8 ± 78.5 N) (P=.011, P<.001, and P=.008, respectively). CONCLUSION: Fracture resistance of ETT depends on the length of the ferrule, as shown by the significantly increased fracture resistance in the 2 mm ferrule group (F2) compared to the groups with shorter ferrule lengths (F0, F1) and without post (NP).

Analysis of the width ratio and wear rate of maxillary anterior teeth in the Korean population.

PURPOSE: The purpose of this study was to compare the width ratio of maxillary anterior teeth according to age in the Korean population and to evaluate the maxillary central incisor width-to-length (W/L) ratio, given differences in age and gender. MATERIALS AND METHODS: Ninety-three Korean adults were divided into 3 groups (n = 31) by age. Group I was 20 - 39 years old, Group II was 40 - 59 years old, and Group III was over 60 years of age. After taking an impression and a cast model of the maxillary arch, the anterior teeth width ratio and central incisor W/L ratio were calculated from standard digital images of the cast models using a graph paper with a digital single lens reflex (DSLR) camera. The calculated ratios were compared among all groups and central incisor W/L ratio were analyzed according to age and gender. All comparative data were statistically analyzed with one-sample t-tests, one-way ANOVAs with Tukey tests, and independent t-tests. RESULTS: No significant differences in maxillary anterior teeth ratios were found among the age groups. The maxillary central incisor W/L ratios in Group III were the greatest and were significantly higher than those in the other groups. The central incisor W/L ratio of men was higher than that of women in Group II. CONCLUSION: Maxillary anterior teeth width ratios were similar in all age groups in the Korean population. The maxillary central incisor was observed as worn teeth in the group over 60 years of age, and a significant difference between genders was found in 40 to 50 year olds.

A New Fast and Simple Border Molding Process for Complete Dentures Using a Compound Stick Gun.

This article describes the use of a newly invented compound stick gun to take impressions for complete denture. The border molding process involves loading the modeling compound in an electric heating device and applying an even thickness of compound on the flange of a custom tray at a proper temperature without hot water tempering. This method provides a quicker and easier border molding process alternative to conventional techniques.

Influence of preparation depths on the fracture load of customized zirconia abutments with titanium insert.

PURPOSE: This study evaluated the fracture load of customized zirconia abutments with titanium insert according to preparation depths, with or without 5-year artificial aging. MATERIALS AND METHODS: Thirty-six identical lithium disilicate crowns (IPS e.max press) were fabricated to replace a maxillary right central incisor and cemented to the customized zirconia abutment with titanium insert on a 4.5×10 mm titanium fixture. Abutments were fabricated with 3 preparation depths (0.5 mm, 0.7 mm, and 0.9 mm). Half of the samples were then processed using thermocycling (temperature: 5-55℃, dwelling time: 120s) and chewing simulation (1,200,000 cycles, 49 N load). All specimens were classified into 6 groups depending on the preparation depth and artificial aging (non-artificial aging groups: N5, N7, N9; artificial aging groups: A5, A7, A9). Static load was applied at 135 degrees to the implant axis in a universal testing machine. Statistical analyses of the results were performed using 1-way ANOVA, 2-way ANOVA, independent t-test and multiple linear regression. RESULTS: The fracture loads were 539.28 ± 63.11 N (N5), 406.56 ± 28.94 N (N7), 366.66 ± 30.19 N (N9), 392.61 ± 50.57 N (A5), 317.94 ± 30.05 N (A7), and 292.74 ± 37.15 N (A9). The fracture load of group N5 was significantly higher than those of group N7 and N9 (P<.017). Consequently, the fracture load of group A5 was also significantly higher than those of group A7 and A9 (P<.05). After artificial aging, the fracture load was significantly decreased in all groups with various preparation depths (P<.05). CONCLUSION: The fracture load of a single anterior implant restored with lithium disilicate crown on zirconia abutment with titanium insert differed depending on the preparation depths. After 5-year artificial aging, the fracture loads of all preparation groups decreased significantly.

Cytotoxicity of soft denture lining materials depending on their component types.

PURPOSE: To evaluate the difference in cytotoxicity of soft denture lining materials depending on their component types. MATERIALS AND METHODS: Ten commercially available soft denture lining materials (SDLM) consisting of five silicone-based materials and five acrylic-based materials were evaluated. For the MTT test, cured SDLM samples were extracted in a culture medium for 24 hours, and L-929 cells were incubated in the extracted medium for 24 hours. Cell viability was determined using a microplate reader and compared with those of the negative control, which were cultured in a culture medium without test material. Agar overlay test was performed for the cured SDLM samples according to International Organization for Standardization (ISO) 7405. RESULTS: Among silicone-based lining materials, GC Reline Soft, Mollosil plus, and Dentusil showed a cell viability of 107.2% ± 4.5%, 102.3% ± 2.84%, and 93.0% ± 8.0%, respectively, compared with the control. Mucopren and Sofreliner Tough displayed significantly lower cell viability (86.4% ± 10.3% and 81.5% ± 4.3%,respectively) compared with the control (P < .05). Among acrylic-based materials, Kooliner, Visco-gel, Soft liner, Dura Base, and Coe-Soft displayed cell viability of 99.2% ± 14.6%, 93.1% ± 9.5%, 89.1% ± 9.8%, 87.6% ± 7.9%, and 75.9% ± 15.7%, respectively, compared with the control. Dura Base and Coe-Soft displayed significantly lower cell viability compared to the control. However, for all tested materials, cell viability exceeded the requirement limit of 70% specified in ISO 10993-5. In the agar overlay test, all five silicone-based materials and acrylic-based Kooliner were ranked as "noncytotoxic." However, Visco-gel was ranked as "mildly cytotoxic," and Soft liner, Coe-Soft, and Dura Base were ranked as "moderately cytotoxic." CONCLUSION: When an acrylic-based soft denture lining material is used, the possibility of a cytotoxic effect should be considered.

Effect of loading time on marginal bone loss around hydroxyapatite-coated implants.

OBJECTIVES: The objective of this study is compare the rate of marginal bone resorption around hydroxyapatite-coated implants given different loading times in order to evaluate their stability. MATERIALS AND METHODS: The study was conducted retrospectively for one year, targeting 41 patients whose treatment areas were the posterior maxilla and the mandible. Osstem TS III HA (Osstem Implant Co., Busan, Korea) and Zimmer TSV-HA (Zimmer Dental, Carlsbad, CA, USA), which employ the new hydroxyapatite coating technique, were used. The patients were divided into two groups - immediate and delayed loading - and the bone level at the time of loading commencement and after one year of loading was measured using periapical radiography. Differences between the groups were evaluated using Mann-Whitney (α=0.05). RESULTS: For all patients as a single group, the survival rate of the implants was 100%, and the mean marginal bone loss was 0.26±0.59 mm. In comparison of the differences by loading, mean marginal bone loss of 0.32±0.69 mm was recorded for the immediate loading group whereas the delayed loading group had mean marginal bone loss of 0.16±0.42 mm. However, the difference was not significant (P>0.05). CONCLUSION: Within the limited observation period of one year, predictable survival rates can be expected when using immediately loaded hydroxyapatite-coated implants.

A morphometric analysis of maxillary central incisor on the basis of facial appearance in Korea.

PURPOSE: We aimed to identify a more esthetic width-to-length ratio by analyzing maxillary central incisor of Korean adult population. Information regarding tooth ratio in the Korean population may be useful to clinicians when restoring anterior teeth. MATERIALS AND METHODS: A total of 40 men and 40 women were included in this study. The NON-MEDIA group included 40 non-celebrities, who were healthy and 25 to 39 years old, with normal dentofacial appearance. The MEDIA group consisted of 40 celebrities selected only on the basis of their soft-tissue facial appearance. The facial photographs of 40 celebrities were collected from the Internet websites. The width and length of the maxillary central incisor were measured using Adobe Photoshop® 7.0, a software for analysis, measurement and edition of photographs. Data were analyzed statistically using the Independent t-test at 5% statistical significance level. RESULTS: The mean ratio for the MEDIA group was 0.77, whereas that of the NON-MEDIA group was 0.88. The difference between the two groups was statistically significant. No significant gender differences were found in the width-to-length ratio in MEDIA group. In NON-MEDIA group, however, there were significant differences between female and male. CONCLUSION: After analyzing maxillary anterior teeth of Korean adults, our results were in accordance with the general Western standards of esthetics. A dentist restoring the natural look and beauty of teeth will have to consider those standards.

Shear bond strength and failure types of polymethyl methacrylate denture base resin and titanium treated with surface conditioner.

This study compared the shear bond strength and failure types of a polymethyl methacrylate (PMMA) denture base resin to commercially pure (CP) titanium, Ti-6Al-4V alloy, and cobalt-chromium alloy using a metal surface conditioner. The PMMA denture base resin (5 x 5 x 5 mm(3)) was cured onto disks, 10 mm in diameter and 2.5-mm thick. The shear bond strength of the PMMA resin with the surface conditioner was significantly higher than that without (P < .05). There was no significant difference between the types of metal. The conditioned specimens showed mixed failures, whereas the nonconditioned specimens exhibited only adhesive failure at the metal-resin interface.

Fracture load of implant-supported zirconia all-ceramic crowns luted with various cements.

This study compared the fracture load and failure types of implant-supported zirconia all-ceramic crowns cemented with various luting agents. The ceramic frameworks were fabricated from a presintered yttria-stabilized zirconium dioxide block using computer-aided design/computer-assisted manufacturing technology, and were then veneered with feldspathic porcelain. Three luting agents were used. Composite resin cement (1,560.78 +/- 39.43 N) showed the highest mean fracture load, followed by acrylic/urethane cement (1,116.20 +/- 77.32 N) and zinc oxide eugenol cement (741.21 +/- 41.95 N) (P < .05). The types of failure varied between groups.

Oral rehabilitation for a patient with oligodontia and maxillary hypoplasia.

An 18 year old female with oligodontia and maxillary hypoplasia was treated using an interdisciplinary team approach involving orthodontists, maxillofacial surgeons and prosthodontists. Full mouth one-piece fixed partial dentures were the final restoration. The fixed partial dentures fabricated for the maxilla and mandible using the concept of a shortened dental arch resulted in improved esthetics and the masticatory function. This paper describes the treatment procedures for an oligodontia patient with alveolar bone hypoplasia.

Effect of adhesive primers on bonding strength of heat cure denture base resin to cast titanium and cobalt-chromium alloy.

STATEMENT OF PROBLEM: The poor chemical bonding of a denture base resin to cast titanium framework often introduces adhesive failure and increases microleakage. PURPOSE: This study evaluated the shear bond strengths of a heat cure denture base resin to commercially pure titanium, Ti-6Al-4V alloy and a cobalt-chromium alloy using two adhesive primers. MATERIAL AND METHODS: Disks of commercially pure titanium, Ti-6Al-4V alloy and a cobalt-chromium alloy were cast. Specimens without the primer were also prepared and used as the controls. The shear bond strengths were measured on a screw-driven universal testing machine. RESULTS: The primers significantly (P < .05) improved the shear bond strengths of the heat cure resin to all metals. However, the specimens primed with the Alloy primer® (MDP monomer) showed higher bond strength than those primed with the MR bond® (MAC-10 monomer) on titanium. Only adhesive failure was observed at the metal-resin interface in the non-primed specimens, while the primed specimens showed mixed failure of adhesive and cohesive failure. CONCLUSIONS: The use of appropriate adhesive metal primers makes it possible not only to eliminate the need for surface preparation of the metal framework before applying the heat cure resins, but also reduce the need for retentive devices on the metal substructure. In particular, the Alloy primer®, which contains the phosphoric acid monomer, MDP, might be clinically more acceptable for bonding a heat cure resin to titanium than a MR bond®, which contains the carboxylic acid monomer, MAC-10.

Comparion of stability in titanium implants with different surface topographies in dogs.

STATEMENT OF PROBLEM: A few of studies which compared and continuously measured the stability of various surface treated implants in the same individual had been performed. PURPOSE: We aim to find the clinical significance of surface treatments by observing the differences in the stabilization stages of implant stability. MATERIAL AND METHODS: Eight different surface topographies of dental implants were especially designed for the present study. Machined surface implants were used as a control group. 4 nano-treated surface implants (20 nm TiO(2) coating surface, heat-treated 80 nm TiO(2) coating surface, CaP coating surface, heat treated CaP coating surface) and 3 micro-treated surface implants [resorbable blast media (RBM) surface, sandblast and acid-etched (SAE) surface, anodized RBM surface] were used as experiment groups. All 24 implants were placed in 3 adult dogs. Periotest® & ISQ values measured for 8 weeks and all animals were sacrificed at 8 weeks after surgery. Then the histological analyses were done. RESULTS: In PTV, all implants were stabilized except 1 failed implants. In ISQ values, The lowest stability was observed at different times for each individual. The ISQ values were showed increased tendency after 5 weeks in every groups. After 4 to 5 weeks, the values were stabilized. There was no statistical correlation between the ISQ values and PTV. In the histological findings, the bone formation was observed to be adequate in general and no differences among the 8 surface treated implants. CONCLUSIONS: In this study, the difference in the stability of the implants was determined not by the differences in the surface treatment but by the individual specificity.

Cell response to a newly developed Ti-10Ta-10Nb alloy and its sputtered nanoscale coating.

STATEMENT OF PROBLEM: The success of titanium implants is due to osseointegration or the direct contact of the implant surface and bone without a fibrous connective tissue interface. PURPOSE: The purpose of this study was to evaluate the osteoblast precursor response to titanium - 10 tantalum - 10 niobium (Ti-Ta-Nb) alloy and its sputtered coating. MATERIAL AND METHODS: Ti-Ta-Nb coatings were sputtered onto the Ti-Ta-Nb disks. Ti6-Al-4V alloy disks were used as controls. An osteoblast precursor cell line, were used to evaluate the cell responses to the 3 groups. Cell attachment was measured using coulter counter and the cell morphology during attachment period was observed using fluorescent microscopy. Cell culture was performed at 4, 8, 12 and 16 days. RESULTS: The sputtered Ti-Ta-Nb coatings consisted of dense nanoscale grains in the range of 30 to 100 nm with alpha-Ti crystal structure. The Ti-Ta-Nb disks and its sputtered nanoscale coatings exhibited greater hydrophilicity and rougher surfaces compared to the Ti-6Al-4V disks. The sputtered nanoscale Ti-Ta-Nb coatings exhibited significantly greater cell attachment compared to Ti-6Al-4V and Ti-Ta-Nb disks. Nanoscale Ti-Ta-Nb coatings exhibited significantly greater ALP specific activity and total protein production compared to the other 2 groups. CONCLUSIONS: It was concluded that nanoscale Ti-Ta-Nb coatings enhance cell adhesion. In addition, Ti-Ta-Nb alloy and its nanoscale coatings enhanced osteoblast differentiation, but did not support osteoblast precursor proliferation compared to Ti-6Al-4V. These results indicate that the new developed Ti-Ta-Nb alloy and its nanoscale Ti-Ta-Nb coatings may be useful as an implant material.

Shear bond strength of composite resin to titanium according to various surface treatments.

STATEMENT OF PROBLEM: When veneering composite resin-metal restoration is prepared, the fact that bond strength between Ti and composite resin is relatively weak should be considered. PURPOSE: The purpose of this study is to evaluate the shear bond strength between the veneering composite resin and commercial pure (CP) Ti / Ti-6Al-4V alloy according to the method of surface treatment. MATERIAL AND METHODS: The disks were cast by two types of metal. Their surfaces were treated by sandblasting, metal conditioner, TiN coating and silicoating respectively. After surface treatment, the disks were veneered by composite resin (Tescera™, Bisco, USA) which is 5 mm in diameter and 3 mm in thickness. The specimens were stored in water at 25℃ for 24 hours, and then evaluated for their shear bond strength by universal testing machine (STM-5®, United Calibration, USA). These values were statistically analyzed. RESULTS: 1. All methods of surface treatment were used in this study satisfied the requirements of ISO 10477 which is the standard of polymer-based crown and bridge materials. 2. The metal conditioner treated group showed the highest value in shear bond strength of CP Ti, silicoated group, TiN coated group, sandblasted group, in following order. 3. The silicoated group showed the highest value in shear bond strength of Ti-6Al-4V alloy, metal conditioner treated group, sandblasted group, TiN coated group, in following order. CONCLUSION: Within the limitations of this study, all methods of surface treatment used in this study are clinically available.

Histologic evaluation and removal torque analysis of nano- and microtreated titanium implants in the dogs.

STATEMENT OF PROBLEM: A number of studies about the nano-treated surfaces of implants have been conducting along with micro-treated surfaces of implants. PURPOSE: The purpose of this study was to get information for the clinical use of nano-treated surfaces compared with micro-treated surfaces by measuring removal torque and analyzing histological characteristics after the placement of various surface-treated implants on femurs of dogs. MATERIAL AND METHODS: Machined surface implants were used as a control group. 4 nano-treated surface implants and 3 micro-treated surface implants [resorbable blast media surface (RBM), sandblast and acid-etched surface (SAE), anodized RBM surface] were used as experimental groups. Removal torque values of implants were measured respectively and the histological analyses were conducted on both 4weeks and 8weeks after implant surgery. The surfaces of removed implants after measuring removal torque values were observed by scanning electron microscopy (SEM) at 8 weeks. RESULTS: 1. Removal torque values of the nano-treated groups were lower than those of micro-treated groups. 2. Removal torque values were similar in the anodized RBM surface groups. 3. On the histological views, there was much of bone formation at 8 weeks, but there was no difference between 4 and 8 weeks, and between the types of implant surfaces as well. CONCLUSION: It is suggested that implant topography is more effective in removal torque test than surface chemistry. To get better clinical result, further studies should be fulfilled on the combined effect of surface topography and chemistry for the implant surface treatments.