Marcelo Suzuki

Publications of Marcelo Suzuki

• Effect of drilling dimension on implant placement torque and early osseointegration stages: an experimental study in dogs.

  Authors: Felipe E Campos, Julio B Gomes, Charles Marin, Hellen S Teixeira, Marcelo Suzuki, Lukasz Witek, Darceny Zanetta-Barbosa, Paulo G Coelho

  Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons. 01/2012; 70(1):e43-50.

  Primary stability has been regarded as a key factor to ensure uneventful osseointegration of dental implants. Such stability is often achieved by placing implants in undersized drilled bone. ThePrimary stability has been regarded as a key factor to ensure uneventful osseointegration of dental implants. Such stability is often achieved by placing implants in undersized drilled bone. The present study evaluated the effect of drilling dimensions in insertion torque and early implant osseointegration stages in a beagle dog model. Six beagle dogs were acquired and subjected to bilateral surgeries in the radii 1 and 3 weeks before death. During surgery, 3 implants, 4 mm in diameter by 10 mm in length, were placed in bone sites drilled to 3.2 mm, 3.5 mm, and 3.8 mm in diameter. The insertion torque was recorded for all samples. After death, the implants in bone were nondecalcified processed and morphologically and morphometrically (bone-to-implant contact and bone area fraction occupancy) evaluated. Statistical analyses were performed using the Kruskal-Wallis test followed by Dunn's post hoc test for multiple comparisons at the 95% level of significance. The insertion torque levels obtained were inversely proportional to the drilling dimension, with a significant difference detected between the 3.2-mm and 3.8-mm groups (P = .003). Despite a significant increase in the bone-to-implant contact over time in vivo for all groups (P = .007), no effect for the drilling dimension was observed. Additionally, no effect of the drilling dimension and time was observed for the bone area fraction occupancy parameter (P = .31). The initial healing pathways differed between implants placed in bone drilled to different dimensions. Although different degrees of torque were observed with different drilling dimensions and these resulted in different healing patterns, no differences in the histometrically evaluated parameters were observed.

• The effect of different implant macrogeometries and surface treatment in early biomechanical fixation: an experimental study in dogs.

  Authors: Paulo G Coelho, Rodrigo Granato, Charles Marin, Hellen S Teixeira, Marcelo Suzuki, Guilherme B Valverde, Malvin N Janal, Tomas Lilin, Estevam A Bonfante

  Journal of the mechanical behavior of biomedical materials. 11/2011; 4(8):1974-81.

  Implant surface characterization and biomechanical testing were made to evaluate the effect of different surface treatments along with different implant bulk configurations expressed as biomechanicalImplant surface characterization and biomechanical testing were made to evaluate the effect of different surface treatments along with different implant bulk configurations expressed as biomechanical fixation at early implantation times. Three implant surfaces, namely bioactive ceramic electrodeposition (ED), alumina-blasted/acid etched (AB/AE), and resorbable blasting media (RBM) were fabricated in three implant macrogeometries (cylindrical, small chamber, and large chamber). All combinations between surface and bulk configurations were placed in the radii of beagle dogs (n=18), which were euthanized 14 and 40 days after surgery (n=9 animals per time in vivo). The implants were subjected to torque to interface fracture. Effects of time, surface, and macrogeometry on torque to interface fracture were evaluated by a GLM at 95% level of significance. The results showed a significant increase in torque as time elapsed in vivo (p<0.001), and that the ED surface presented significantly higher values compared to AB/AE and RBM (p<0.001) at both times. The small chamber only presented a significantly higher biomechanical fixation compared to other geometries at 40 days in vivo (p=0.02). Biomechanical fixation at 14 and 40 days was affected by implant surface treatment, whereas implant design only affected results at 40 days in vivo.

• Reliability testing of indirect composites as single implant restorations.

  Authors: Marcelo Suzuki, Estevam Bonfante, Nelson Rfa Silva, Paulo G Coelho

  Journal of prosthodontics : official journal of the American College of Prosthodontists. 10/2011; 20(7):528-34.

  To investigate the reliability and failure modes of indirect composites as single-unit implant crowns. Thirty-eight custom-milled titanium alloy locking-taper abutments were divided into two groupsTo investigate the reliability and failure modes of indirect composites as single-unit implant crowns. Thirty-eight custom-milled titanium alloy locking-taper abutments were divided into two groups (n = 19 each), and crown build-up of a mandibular molar was accomplished using two indirect composite systems (Ceramage, Shofu, Kyoto, Japan; Diamond Crown, DRM, Branford, CT). Three crowns of each material were loaded until failure for determination of the step-stress profiles. Reliability testing started at a load 30% of the mean load to failure and used three profiles with increasing fatigue loading (step stress). Weibull curves with 300 N stress and 90% confidence intervals were calculated and plotted using a power-law relationship. Weibull modulus "Beta" and characteristic strength "Eta" were identified, and a contour plot was used (Beta vs. Eta) for examining differences between groups. Specimens were inspected in polarized light and scanning electron microscope for fracture analysis. Use level Weibull probability showed fatigue being a damage factor only for the Ceramage group (β= 3.39) but not for the Diamond Crown group (β= 0.40). Overlap in the confidence bounds resulted in no statistical difference. Irrespective of composite system, fracture initiated in the region immediately below the contact between the indenter and the cusp, with the crack propagating toward the margins of cohesive failure. No significant differences were observed in life and Weibull probability calculations for Ceramage and Diamond Crown veneered onto Ti alloy abutments. Failure modes comprised composite veneer chippings.

• Reimplantation of Dental Implants following Ligature-Induced Peri-Implantitis: A Pilot Study in Dogs.

  Authors: Liran Levin, Hadar Zigdon, Paulo G Coelho, Marcelo Suzuki, Eli E Machtei

  Clinical implant dentistry and related research. 07/2011;

  Objectives: This preliminary investigation aimed to evaluate the potential of contaminated implants to reosseointegrate into pristine sites and, in addition, to assess the potential ofObjectives: This preliminary investigation aimed to evaluate the potential of contaminated implants to reosseointegrate into pristine sites and, in addition, to assess the potential of osseointegration of new implants in peri-implantitis sockets in a canine model. Methods: All mandibular premolars were bilaterally extracted from two mongrel dogs. Following 12 weeks of healing, two dental implants were inserted on each hemiarch. Forty-five days following implant placement, a silk ligature secured with cyanoacrylate was placed around the implants' cervical region in order to induce peri-implantitis. After another 45 days from ligature placement, the implants were mechanically removed using counter rotation with a ratchet and were reimplanted without any decontamination (neither rinsing nor chemical or mechanical cleaning) in adjacent pristine zones. In sites where implants were removed, new, wider-diameter implants were placed in the infected sockets. Forty-five days following reimplantation surgery, the dogs were sacrificed; nondecalcified specimens were processed and toluidine blue stained for morphologic and morphometric (bone-to-implant contact [BIC]) assessment under an optical microscope. Results: In dog 1 all the implants (both in the pristine and in the infected sites) survived and osseointegrated while in dog 2, six out of eight implants failed to osseointegrate and exfoliated. Overall, the mean BIC of all implants was 51.08% (SD 20.54). The mean BIC for the infected implants placed into pristine sites was 51.48% ± 26.29% (SD) and the mean BIC for the new implants in peri-implantitis socket was 50.58% ± 14.27% (SD). Conclusions: Within the limitations of this preliminary investigation, especially the small number of animals, osseointegration seems to be achievable both in infected sites and around contaminated implant surfaces.

• Effect of drilling technique on the early integration of plateau root form endosteal implants: an experimental study in dogs.

  Authors: Gabriela Giro, Charles Marin, Rodrigo Granato, Estevam A Bonfante, Marcelo Suzuki, Malvin N Janal, Paulo G Coelho

  Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons. 04/2011; 69(8):2158-63.

  This study tested the hypothesis that early integration of plateau root form endosseous implants is significantly affected by surgical drilling technique. Sixty-four implants were bilaterally placedThis study tested the hypothesis that early integration of plateau root form endosseous implants is significantly affected by surgical drilling technique. Sixty-four implants were bilaterally placed in the diaphysial radius of 8 beagles and remained 2 and 4 weeks in vivo. Half the implants had an alumina-blasted/acid-etched surface and the other half a surface coated with calcium phosphate. Half the implants with the 2 surface types were drilled at 50 rpm without saline irrigation and the other half were drilled at 900 rpm under abundant irrigation. After euthanasia, the implants in bone were nondecalcified and referred for histologic analysis. Bone-to-implant contact, bone area fraction occupancy, and the distance from the tip of the plateau to pristine cortical bone were measured. Statistical analyses were performed by analysis of variance at a 95% level of significance considering implant surface, time in vivo, and drilling speed as independent variables and bone-to-implant contact, bone area fraction occupancy, and distance from the tip of the plateau to pristine cortical bone as dependent variables. The results showed that both techniques led to implant integration and intimate contact between bone and the 2 implant surfaces. A significant increase in bone-to-implant contact and bone area fraction occupancy was observed as time elapsed at 2 and 4 weeks and for the calcium phosphate-coated implant surface compared with the alumina-blasted/acid-etched surface. Because the surgical drilling technique did not affect the early integration of plateau root form implants, the hypothesis was refuted.

• Evaluation of a nanometer roughness scale resorbable media-processed surface: a study in dogs.

  Authors: Charles Marin, Rodrigo Granato, Estevam A Bonfante, Marcelo Suzuki, Malvin N Janal, Paulo G Coelho

  Clinical oral implants research. 04/2011; 23(1):119-24.

  This study compared the biomechanical fixation and bone-to-implant contact (BIC) of implants with different surfaces treatment (experimental - resorbable blasting media-processed nanometer roughnessThis study compared the biomechanical fixation and bone-to-implant contact (BIC) of implants with different surfaces treatment (experimental - resorbable blasting media-processed nanometer roughness scale surface, and control - dual acid-etched) in a dog model. Surface characterization was made in six implants by means of scanning electron microscopic imaging, atomic force microscopy to evaluate roughness parameters, and X-ray photoelectron spectroscopy (XPS) for chemical assessment. The animal model comprised the bilateral placement of control (n=24) and experimental surface (n=24) implants along the proximal tibiae of six mongrel dogs, which remained in place for 2 or 4 weeks. Half of the specimens were biomechanically tested (torque), and the other half was subjected to histomorphologic/morphometric evaluation. BIC and resistance to failure measures were each evaluated as a function of time and surface treatment in a mixed model ANOVA. Surface texturing was significantly higher for the experimental compared with the control surface. The survey XPS spectra detected O, C, Al, and Ti at the control group, and Ca (∼0.2- 0.9%) and P (∼1.7- 4.1%) besides O, C, Al, and Ti at experimental surfaces. While no statistical difference in BIC was found between experimental and control surfaces or between 2 and 4 weeks in vivo, both longer time and use of experimental surface significantly increased resistance to failure. The experimental surface resulted in enhanced biomechanical fixation but comparable BIC relative to control, suggesting higher bone mechanical properties around the experimental implants.

• Histologic and Biomechanical Evaluation of Two Resorbable Blasting Media (RBM) Implant Surfaces at Early Implantation Times.

  Authors: Charles Marin, Estevam Augusto Bonfante, Ryan Jeong, Rodrigo Granato, Gabriela Giro, Marcelo Suzuki, Claiton Heitz, Paulo G Coelho

  The Journal of oral implantology. 04/2011;

  Abstract This study evaluated 3 implant surfaces in a dog model: 1) Resorbable-blasting media + acid-etched (RBMa), alumina-blasting + acid-etching (AB/AE), and AB/AE + RBMa (Hybrid). All theAbstract This study evaluated 3 implant surfaces in a dog model: 1) Resorbable-blasting media + acid-etched (RBMa), alumina-blasting + acid-etching (AB/AE), and AB/AE + RBMa (Hybrid). All the surfaces were minimally rough, and Ca and P were present for the RBMa and Hybrid surfaces. Following 2 weeks in vivo no significant differences were observed for torque, bone-to-implant contact, and bone-area fraction occupied measurements. Newly formed woven bone was observed in proximity with all surfaces.

• The effect of alterations on resorbable blasting media processed implant surfaces on early bone healing: a study in rabbits.

  Authors: Charles Marin, Estevam A Bonfante, Rodrigo Granato, Marcelo Suzuki, Jose M Granjeiro, Paulo G Coelho

  Implant dentistry. 04/2011; 20(2):167-77.

  Etching resorbable blasting media (RM) processed implants is a common engineering procedure, but the interplay between the resulting physicochemical properties and its effects on early bone healingEtching resorbable blasting media (RM) processed implants is a common engineering procedure, but the interplay between the resulting physicochemical properties and its effects on early bone healing have not been thoroughly addressed. Screw-root form implant surfaces were treated with 1 of 3 methods: grit (alumina) blasted/acid etching, RM, and RM + acid etching (RMAA). Surface topography (n = 3 each) was characterized by scanning electron microscopy and atomic force microscopy and chemical characterization by x-ray photoelectron spectroscopy analysis. The implants were placed at the distal femur of 16 rabbits, where 3 implants, 1 from each surface, were placed bilaterally remaining 4 and 8 weeks in vivo. After euthanization, one half of the specimens were torqued to interface failure at a rate of ∼0.196 radians/min and the other half were nondecalcified processed for histomorphology and bone-to-implant contact evaluation. Physicochemical characterization showed that the grit (alumina) blasted/acid-etched surface was rougher than RM and RMAA. Higher levels of calcium and phosphorous were observed for the RM surface compared with the RMAA surface. No significant differences were observed in torque and bone-to-implant contact between surfaces at 4 or 8 weeks. Histomorphologic evaluation showed woven bone formation around all surfaces at 4 weeks, and its initial replacement by lamellar bone at 8 weeks. Despite differences in texture/chemistry, all implant surfaces were biocompatible and osseoconductive, and led to comparable in vivo bone fixation and measurable histomorphometric parameters.

• Biomechanical and histologic evaluation of non-washed resorbable blasting media and alumina-blasted/acid-etched surfaces.

  Authors: Paulo G Coelho, Charles Marin, Rodrigo Granato, Gabriela Giro, Marcelo Suzuki, Estevam A Bonfante

  Clinical oral implants research. 03/2011; 23(1):132-5.

  To compare the biomechanical fixation and histomorphometric parameters between two implant surfaces: non-washed resorbable blasting media (NWRBM) and alumina-blasted/acid-etched (AB/AE), in a dogTo compare the biomechanical fixation and histomorphometric parameters between two implant surfaces: non-washed resorbable blasting media (NWRBM) and alumina-blasted/acid-etched (AB/AE), in a dog model. The surface topography was assessed by scanning electron microscopy, optical interferometry and chemistry by X-ray photoelectron spectroscopy (XPS). Six beagle dogs of ∼1.5 years of age were utilized and each animal received one implant of each surface per limb (distal radii sites). After a healing period of 3 weeks, the animals were euthanized and half of the implants were biomechanically tested (removal torque) and the other half was referred to nondecalcified histology processing. Histomorphometric analysis considered bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO). Following data normality check with the Kolmogorov-Smirnov test, statistical analysis was performed by paired t-tests at 95% level of significance. Surface roughness parameters S(a) (average surface roughness) and S(q) (mean root square of the surface) were significantly lower for the NWRBM compared with AB/AE. The XPS spectra revealed the presence of Ca and P in the NWRBM. While no significant differences were observed for both BIC and BAFO parameters (P>0.35 and P>0.11, respectively), a significantly higher level of torque was observed for the NWRBM group (P=0.01). Bone morphology was similar between groups, which presented newly formed woven bone in proximity with the implant surfaces. A significant increase in early biomechanical fixation was observed for implants presenting the NWRBM surface.

• Effect of Si addition on Ca- and P-impregnated implant surfaces with nanometer-scale roughness: an experimental study in dogs.

  Authors: Paulo G Coelho, Rodrigo Granato, Charles Marin, Ryo Jimbo, Siyan Lin, Lukasz Witek, Marcelo Suzuki, Estevam A Bonfante

  Clinical oral implants research. 03/2011; 23(3):373-378.

  Objectives: To investigate the effect of Si addition on a nanometer-scale roughness Ca and P implant surfaces in a canine tibia model by biomechanical and histomorphometric evaluations. Material andObjectives: To investigate the effect of Si addition on a nanometer-scale roughness Ca and P implant surfaces in a canine tibia model by biomechanical and histomorphometric evaluations. Material and methods: The implant surfaces comprised a resorbable media CaP microblasted (control) and a CaP resorbable media+silica-boost microblasted (experimental) surfaces. Surfaces were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and optical interferometry (IFM) down to the nanometric level. The animal model involved the bilateral placement of control (n=24) and experimental surface (n=24) implants along the proximal tibiae of six dogs, remaining in vivo for 2 or 4 weeks. After euthanization, half of the specimens were torqued-to-interface failure, and the other half was subjected to histomorphologic and bone-to-implant contact (BIC) evaluation. Torque and BIC statistical evaluation was performed by the Friedman test at 95% level of significance, and comparisons between groups was performed by the Dunn test. Results: IFM and SEM observations depicted comparable roughness parameters for both implant surfaces on the micrometer and nanometer scales. XPS analysis revealed similar chemical composition, except for the addition of Si on the experimental group. Torque-to-interface failure and BIC mean values showed no significant differences (P=0.25 and 0.51, respectively) at both 2- and 4-week evaluation points for experimental and control groups. Early bone healing histomorphologic events were similar between groups. Conclusions: The experimental surface resulted in not significantly different biomechanical fixation and BIC relative to control. Both surfaces were biocompatible and osseoconductive. To cite this article: Coelho PG, Granato R, Marin C, Jimbo R, Lin S, Witek L, Suzuki M, Bonfante EA. Effect of Si addition on Ca- and P-impregnated implant surfaces with nanometer-scale roughness: an experimental study in dogs. Clin. Oral Impl. Res. 23, 2012; 373-378. doi: 10.1111/j.1600-0501.2010.02150.x.

• Sealing Capability and SEM Observation of the Implant-Abutment Interface.

  Authors: Fabio C Lorenzoni, Paulo G Coelho, Gerson Bonfante, Ricardo M Carvalho, Nelson R F A Silva, Marcelo Suzuki, Thelma Lopes Silva, Estevam A Bonfante

  International journal of dentistry. 01/2011; 2011:864183.

  To evaluate the sealing capability of external hexagon implant systems and assess the marginal fit, two groups (n = 10 each) were employed: SIN (Sistema de Implantes Nacional, Brazil) and Osseotite,To evaluate the sealing capability of external hexagon implant systems and assess the marginal fit, two groups (n = 10 each) were employed: SIN (Sistema de Implantes Nacional, Brazil) and Osseotite, (Biomet 3i, USA). Sealing capability was determined by placing 0.7 μL of 1% acid-red solution in the implant wells before the torque of their respective abutments. Specimens were then placed into 2.5 mL vials filled with 1.3 mL of distilled water with the implant-abutment interface submerged. Three samples of 100 μL water were collected at previously determinate times. The absorbance was measured with a spectrophotometer, and the data were analyzed by Two-way ANOVA (P < .05) and Tukey's test. Marginal fit was determined using SEM. Leakage was observed for both groups at all times and was significantly higher at 144 hrs. SEM analysis depicted gaps in the implant-abutment interface of both groups. Gaps in the implant-abutment interface were observed along with leakage increased at the 144 hrs evaluation period.

• Characterization of five different implant surfaces and their effect on osseointegration: a study in dogs.

  Authors: Paulo G Coelho, Estevam A Bonfante, Roberto S Pessoa, Charles Marin, Rodrigo Granato, Gabriela Giro, Lukasz Witek, Marcelo Suzuki

  Journal of periodontology. 11/2010; 82(5):742-50.

  Chemical modification of implant surface is typically associated with surface topographic alterations that may affect early osseointegration. This study investigates the effects of controlled surfaceChemical modification of implant surface is typically associated with surface topographic alterations that may affect early osseointegration. This study investigates the effects of controlled surface alterations in early osseointegration in an animal model. Five implant surfaces were evaluated: 1) alumina-blasting, 2) biologic blasting, 3) plasma, 4) microblasted resorbable blasting media (microblasted RBM), and 5) alumina-blasting/acid-etched (AB/AE). Surface topography was characterized by scanning electron microscopy and optical interferometry, and chemical assessment by x-ray photoelectron spectroscopy. The implants were placed in the radius of six dogs, remaining 2 and 4 weeks in vivo. After euthanization, specimens were torqued-to-interface failure and non-decalcified-processed for histomorphologic bone-implant contact, and bone area fraction-occupied evaluation. Statistical evaluation was performed by one-way analysis of variance (P <0.05) and post hoc testing by the Tukey test. The alumina-blasting surface presented the highest average surface roughness and mean root square of the surface values, the biologic blasting the lowest, and AB/AE an intermediate value. The remaining surfaces presented intermediate values between the biologic blasting and AB/AE. The x-ray photoelectron spectroscopy spectra revealed calcium and phosphorus for the biologic blasting and microblasted RBM surfaces, and the highest oxygen levels for the plasma, microblasted RBM, and AB/AE surfaces. Significantly higher torque was observed at 2 weeks for the microblasted RBM surface (P <0.04), but no differences existed between surfaces at 4 weeks (P >0.74). No significant differences in bone-implant contact and bone area fraction-occupied values were observed at 2 and 4 weeks. The five surfaces were osteoconductive and resulted in high degrees of osseointegration and biomechanical fixation.

• Histologic and Biomechanical Evaluation of Alumina-Blasted/Acid-Etched and Resorbable Blasting Media Surfaces.

  Authors: Estevam Bonfante, Charles Marin, Rodrigo Granato, Marcelo Suzuki, Jenni Hjerppe, Lukasz Witek, Paulo Coelho

  The Journal of oral implantology. 10/2010;

  Abstract This study evaluated the early biomechanical fixation and bone-to-implant contact (BIC) of an alumina-blasted/acid-etched (AB/AE) compared to an experimental resorbable blasting media (RBM)Abstract This study evaluated the early biomechanical fixation and bone-to-implant contact (BIC) of an alumina-blasted/acid-etched (AB/AE) compared to an experimental resorbable blasting media (RBM) surface in a canine model. Higher texturization was observed for the RBM compared to the AB/AE surface and the presence of Ca and P was only observed for the RBM surface. Time in vivo and implant surface did not influence torque. BIC significantly increased from 2 to 4 weeks for both surfaces.

• Histomorphologic and bone-to-implant contact evaluation of dual acid-etched and bioceramic grit-blasted implant surfaces: an experimental study in dogs.

  Authors: Marcelo Suzuki, Marcia V M Guimaraes, Charles Marin, Rodrigo Granato, Carlos A O Fernandes, Jose N Gil, Paulo G Coelho

  Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons. 08/2010; 68(8):1877-83.

  The objective of this study was to histologically evaluate a bioceramic grit-blasted and acid-etched surface (presenting calcium and phosphorous incorporation within the surface and its oxide) versusThe objective of this study was to histologically evaluate a bioceramic grit-blasted and acid-etched surface (presenting calcium and phosphorous incorporation within the surface and its oxide) versus a dual acid-etched (no calcium and phosphorous, control) moderately rough implant surface in a dog tibia model. Implants 3 x 10 mm were placed bilaterally along the proximal tibia of 6 Doberman dogs and remained for 2 and 4 weeks in vivo. After the dogs were euthanized, the implants were nondecalcified processed to approximately 30-microm-thick plates. Transmitted light optical microscopy was used to evaluate healing patterns and bone-to-implant contact. Statistical analysis was performed by 1-way analysis of variance at the 95% level of significance and by Tukey post hoc tests. At 2 weeks, histologic evaluation showed woven bone formation throughout the perimeter of both implant surfaces. However, replacement of woven bone by lamellar bone was only observed around the test surface at 4 weeks in vivo. No significant differences in bone-to-implant contact were observed for the different groups (P > .27). Despite nonsignificant differences between bone-to-implant contact for the different surfaces and times in vivo, higher degrees of bone organization were observed for the test implants. Biomechanical testing is warranted to verify potential differences in biomechanical fixation effectiveness between surfaces.

• Effect of surface modifications on early bone healing around plateau root form implants: an experimental study in rabbits.

  Authors: Marcelo Suzuki, Monica D Calasans-Maia, Charles Marin, Rodrigo Granato, Jose N Gil, Jose M Granjeiro, Paulo G Coelho

  Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons. 07/2010; 68(7):1631-8.

  The objective of the present study was to evaluate the biomechanical fixation and bone-to-implant contact (BIC) of plateau root form implants of varied surfaces. Plateau root form implants, 3.5 mm inThe objective of the present study was to evaluate the biomechanical fixation and bone-to-implant contact (BIC) of plateau root form implants of varied surfaces. Plateau root form implants, 3.5 mm in diameter, 8 mm in length, with 4 surfaces (n = 16 each)--machined, alumina-blasted/acid-etched, alumina-blasted/acid-etched plus nanothickness bioceramic coating, and plasma-sprayed calcium-phosphate--were used. They were bilaterally placed at the distal femur of 16 New Zealand rabbits and remained in place for 2 and 4 weeks in vivo. After euthanizing the rabbits, the implants were subjected to torque to interface fracture and were subsequently processed as nondecalcified approximately 30-microm-thickness slides for histomorphologic analysis and BIC determination. Statistical analysis was performed using analysis of variance at the 95% level of significance, considering implantation time and implant surface as independent variables and the torque-to-interface fracture and BIC as dependent variables. The torque-to-interface fracture was significantly affected by the implant surface (P < .001) but was not affected by the implantation time (P > .20). The implantation time and implant surface had significant effects on the BIC (P < .04 and P < .001, respectively). The greatest torque-to-interface fracture and BIC was observed for the plasma-sprayed calcium-phosphate. The implant surface significantly influenced early bone healing around plateau root form implants.

• Biomechanical and histomorphometric analysis of etched and non-etched resorbable blasting media processed implant surfaces: an experimental study in dogs.

  Authors: Charles Marin, Rodrigo Granato, Marcelo Suzuki, Malvin N Janal, Jose N Gil, Carlos Nemcovsky, Estevam A Bonfante, Paulo G Coelho

  Journal of the mechanical behavior of biomedical materials. 07/2010; 3(5):382-91.

  This study characterized the interplay between topography/chemistry and early bone response of etched and no-etched resorbable blasted media (RBM) processed surfaces. Screw-root form Ti-6Al-4VThis study characterized the interplay between topography/chemistry and early bone response of etched and no-etched resorbable blasted media (RBM) processed surfaces. Screw-root form Ti-6Al-4V implants treated with alumina blasting/acid-etching (AB/AE), RBM alone (RBM), and RBM + acid-etching (RBMa) were evaluated. The surface was characterized by scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. Implants placed in the tibia of dogs remained 3 and 5 weeks in vivo. Following euthanasia, half of the specimens were torqued to interface failure and the remaining subjected to bone-to-implant contact (BIC) and bone area fraction occupied (BAFO) between threads evaluation. The AB/AE surface was rougher than the RBM and RBMa. Higher levels of calcium and phosphorous were observed for the RBM surface compared to the RBMa. No significant differences were observed in torque, BIC, and BAFO between surfaces. Woven bone formation at 3 weeks and its initial replacement by lamellar bone at 5 weeks were observed around all implants' surfaces.

• Biomechanical evaluation of endosseous implants at early implantation times: a study in dogs.

  Authors: Paulo G Coelho, Rodrigo Granato, Charles Marin, Estevam A Bonfante, Jose N O Freire, Malvin N Janal, Jose N Gil, Marcelo Suzuki

  Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons. 07/2010; 68(7):1667-75.

  This study tested the null hypothesis that differences in surgical instrumentation, macrogeometry, and surface treatment imposed by different implant systems do not affect early biomechanicalThis study tested the null hypothesis that differences in surgical instrumentation, macrogeometry, and surface treatment imposed by different implant systems do not affect early biomechanical fixation in a canine mandible model. The lower premolars of 6 beagle dogs were extracted and the ridges allowed to heal for 8 weeks. Thirty-six (n = 12 each group) implants were bilaterally placed, remaining for 1 and 3 weeks in vivo. The implant groups were as follows: group 1, Ti-6Al-4V with a dual acid-etched surface with nanometer scale discrete crystalline deposition (Nanotite; Certain Biomet-3i, West Palm Springs, FL); group 2, Ti-6Al-4V with a titanium oxide-blasted fluoride-modified surface chemistry (Osseospeed 4.0 S; Astra Tech, Mölndal, Sweden); group 3: Ti-6Al-4V with a bioceramic microblasted surface (Ossean; Intra-Lock International, Boca Raton, FL). Following euthanasia, implants were torqued to interface failure and histologically evaluated. General linear modeling (ANOVA) at 95% level of significance was performed. Histology showed that interfacial bone remodeling and initial woven bone formation were observed around all implant groups at 1 and 3 weeks. Torque values were significantly affected by time in vivo, implant group, and their interaction (P = .016, P < .001, and P = .001, respectively). Regarding torque values, group 3, group 2, and group 1 ranked highest, intermediate, and lowest, respectively. Early biomechanical fixation at 1 and 3 weeks was affected by surgical instrumentation, macrogeometry, and surface treatment present for one of the implant systems tested. The null hypothesis was rejected.

• Histomorphologic and histomorphometric evaluation of various endosseous implant healing chamber configurations at early implantation times: a study in dogs.

  Authors: Charles Marin, Rodrigo Granato, Marcelo Suzuki, Jose N Gil, Malvin N Janal, Paulo G Coelho

  Clinical oral implants research. 06/2010; 21(6):577-83.

  The objective of this study was to evaluate the early healing of endosseous implants presenting various healing chamber configurations in a beagle dog mandible model. The four premolars of 12 beagleThe objective of this study was to evaluate the early healing of endosseous implants presenting various healing chamber configurations in a beagle dog mandible model. The four premolars of 12 beagle dogs were extracted and allowed to heal for a period of 8 weeks. Implants allowing six different healing chamber configurations were placed in each dog (three per side, six configurations per dog). The animals were sacrificed after 3 and 5 weeks in vivo (n=6 per time in vivo), and the implants were non-decalcified processed to slides of approximately 30 microm thickness. Bone-to-implant contact (BIC) and bone area fraction occupied (BAFO) within the healing chamber were quantified. Statistical analysis was performed by a GLM ANOVA model at 5% significance level. Osseointegration and healing with woven bone filling throughout all healing chambers was observed. Replacement of woven bone by lamellar bone showing primary osteonic structures was observed at 5 weeks. BIC was significantly affected by healing chamber configuration (P<0.001) and was not affected by time in vivo (P>0.42) at 3 and 5 weeks in vivo. BAFO was not affected by healing chamber configuration (P>0.14) however significantly increased over implantation time (P<0.001). Regardless of healing chamber design and dimensions considered, healing allowed the devices osseointegration. However, healing chamber configuration significantly affected osseointegration measurable parameters such as BIC.

• Biomechanical and bone histomorphologic evaluation of four surfaces on plateau root form implants: an experimental study in dogs.

  Authors: Paulo G Coelho, Rodrigo Granato, Charles Marin, Estevam A Bonfante, Malvin N Janal, Marcelo Suzuki

  Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics. 05/2010; 109(5):e39-45.

  To evaluate the early bone response to plateau root form dental implants with 4 different surface treatments. Surface treatments comprised (n = 12 each): as-machined (M), alumina-blasted/acid-etchedTo evaluate the early bone response to plateau root form dental implants with 4 different surface treatments. Surface treatments comprised (n = 12 each): as-machined (M), alumina-blasted/acid-etched (AB/AE), alumina-blasted/acid-etched + nanothickness bioceramic coating (Nano), and plasma-sprayed calcium phosphate (PSCaP). Implants were placed in the radius diaphyses of 12 beagle dogs, remaining in vivo for 3 and 5 weeks. After euthanasia, the implants were subjected to torque to interface fracture and subsequently nondecalcified for histomorphology. Statistical analysis was performed by a GLM analysis of variance model at 5% significance level. Torque to interface fracture was significantly greater for the PSCaP group than for other groups (P < .001). Histomorphologic analysis showed woven bone formation around all implant surfaces at 3 weeks, and its replacement by lamellar bone at 5 weeks. Time in vivo did not affect torque measures. The PSCaP surface increased the early bone biomechanical fixation of plateau root form implants.

• Surface treatment at the cervical region and its effect on bone maintenance after immediate implantation: an experimental study in dogs.

  Authors: Paulo G Coelho, Charles Marin, Rodrigo Granato, Estevam A Bonfante, Cirilo P Lima, Marcelo Suzuki

  Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics. 04/2010; 110(2):182-7.

  The aim of this study was to evaluate the effect of surface treatment at the cervical region of endosseous dental implants on the alveolar bone remodeling after implantation immediately after toothThe aim of this study was to evaluate the effect of surface treatment at the cervical region of endosseous dental implants on the alveolar bone remodeling after implantation immediately after tooth extraction in a dog model. The third and fourth premolars of 6 dogs were bilaterally extracted with a full-thickness flap, and threaded implants presenting a textured or a polished surface at the cervical regions were placed on the distal root extraction sockets. Submerged healing was allowed for 4 weeks, and bone-to-implant contact (BIC) and buccal and lingual bone loss were morphometrically measured. The BIC and lingual bone loss were not significantly different between textured and polished groups. Significantly lower buccal bone loss (P < .01) was observed for the textured surface at 4 weeks in vivo. Textured surface implants placed immediately after tooth extraction resulted in less bone loss only at the buccal cervical region compared with smooth surface implants.