Marcia V M Guimaraes

Publications of Marcia V M Guimaraes

• 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.

• Early Bone Healing around Different Implant Bulk Designs and Surgical Techniques: A Study in Dogs.

  Authors: Paulo G Coelho, Marcelo Suzuki, Marcia V M Guimaraes, Charles Marin, Rodrigo Granato, Jose N Gil, Robert J Miller

  Clinical implant dentistry and related research. 05/2009;

  ABSTRACT Purpose: To evaluate the bone healing response to different implant root shape designs in a dog model. Materials and Methods: Three by eight millimeter screw-type short-pitch (SP) andABSTRACT Purpose: To evaluate the bone healing response to different implant root shape designs in a dog model. Materials and Methods: Three by eight millimeter screw-type short-pitch (SP) and large-pitch (LP) implants (Intra-Lock International, Boca Raton, FL, USA), and 4.5 x 6 mm plateau (P) implants (Bicon LLC, Boston, MA, USA) were placed along the proximal tibia of six dogs for 2 and 4 weeks. The combination of implant design and final osteotomy drilling resulted in healing chambers for the LP and P implants. The implants were nondecalcified processed to plates of approximately 30-microm thickness and were evaluated by optical microscopy for healing patterns and bone-to-implant contact (BIC). One-way analysis of variance at 95% level of significance and Tukey's test were utilized for multiple comparisons among the groups' BIC. Results: Microscopy showed a approximately 150-microm region of newly deposited bone along the whole perimeter of SP implants, near the edge of the LP implant threads, and plateau tips for P implants. Rapid woven bone formation and filling was observed in regions where surgery and implant design resulted in healing chambers. No significant differences in BIC were observed (p > .75). Conclusions: Different implant design/surgical protocol resulted in varied bone healing patterns. However, the BIC and bone morphology evolution between implant designs were comparable. Regardless of the combination between implant design and final osteotomy drilling, bone morphology evolution from 2 to 4 weeks was comparable.

• Histomorphometric evaluation of alumina-blasted/acid-etched and thin ion beam-deposited bioceramic surfaces: an experimental study in dogs.

  Authors: Marcelo Suzuki, Marcia V M Guimaraes, Charles Marin, Rodrigo Granato, José Nazareno Gil, Paulo G Coelho

  Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons. 04/2009; 67(3):602-7.

  PURPOSE: In an attempt to overcome the potential long-term limitations observed with plasma-sprayed hydroxyapatite-coated implants, nanothickness bioceramic coatings have been processed ontoPURPOSE: In an attempt to overcome the potential long-term limitations observed with plasma-sprayed hydroxyapatite-coated implants, nanothickness bioceramic coatings have been processed onto previously grit-blasted/acid-etched surfaces. Our objective was to evaluate the bone response to alumina-blasted/acid-etched and a thin ion beam-deposited bioceramic (Test) implant surfaces at 2 and 4 weeks in vivo with a dog tibia model. MATERIALS AND METHODS: Plateau root form implants (5 x 6 mm) were placed bilaterally along the proximal tibia of 6 Doberman dogs and remained for 2 and 4 weeks in vivo (n=6 per implant type and time in vivo). After euthanization, the implants were processed in a nondecalcified form and reduced to approximately 30 mum-thickness plates. Transmitted light optical microscopy at various magnifications was used to qualitatively evaluate the bone healing patterns. Bone-to-implant contact (BIC) was determined and 1-way ANOVA at 95% level of significance with Tukey's post-hoc multiple comparisons was used for statistical analysis. RESULTS: Histomorphology showed new bone formation filling the spaces between the plateaus at both in vivo time intervals through large quantities of woven bone formation. A higher degree of bone organization was observed between the plateaus of Test implants at 4 weeks in vivo than the alumina-blasted/acid-etched implants. No significant differences in BIC were observed for the different groups (P> .86). CONCLUSION: Despite nonsignificant differences between BIC for the different implant surfaces and times in vivo, higher degrees of bone organization were observed for the Test implants at 4 weeks, and biomechanical testing is suggested to verify its biomechanical fixation effectiveness.