Publications by authors named "Luiz Antônio Salata"

22 Publications

  • Page 1 of 1

Immediate loading of implants in the edentulous mandible: a multicentre study.

Oral Maxillofac Surg 2016 Dec 16;20(4):385-390. Epub 2016 Sep 16.

Department of Oral & Maxillofacial Surgery and Periodontics, Faculty of Dentistry of Ribeirão Preto, University of São Paulo, São Paulo, Brazil.

Purpose: The aim of this prospective study was to investigate the two-year outcomes following immediate loading of mono-cortically engaged implants.

Materials And Methods: Thirty healthy mandible edentulous patients with an average age of 67.3 years and presenting with sufficient bony ridge at the mandible symphysis were included in the study. Four Astra Tech, Ti-Oblast implants were installed between the mental foramina using the mono-cortical anchorage technique. The primary stability of the implants was assessed by resonance frequency analysis (RFA). After uni-abutments were placed, a temporary bridge was constructed and fixed the same day. The definitive bridges were installed 6 weeks after implant surgery. Five of 120 placed implants were lost in four patients during the first 6 weeks and these patients were excluded from the follow-up. The changes in marginal bone level (n = 20) were evaluated in Brazilian and Swedish groups at baseline, 6 weeks, 6 months, 12 months and 24 months. The RFA (n = 30) was evaluated at baseline, 6 weeks, 6 months, 12 months and 24 months postoperatively.

Results: Compared with baseline measurements, the postoperative values for marginal bone level (6 weeks, 6 months, 12 months and 24 months) were significantly reduced (p < 0.05), while no differences were observed in the RFA analysis (12 months and 24 months).

Conclusions: The immediate loading of mono-cortically engaged implants in the edentulous mandible is safe and predictable and implant stability remains excellent after 2-year follow-up.
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http://dx.doi.org/10.1007/s10006-016-0577-yDOI Listing
December 2016

Early Osseointegration Events on Neoss® ProActive and Bimodal Implants: A Comparison of Different Surfaces in an Animal Model.

Clin Implant Dent Relat Res 2015 Dec 20;17(6):1060-72. Epub 2014 Feb 20.

Department of Oral and Maxillofacial Surgery and Periodontics, Faculty of Dentistry, University of São Paulo, São Paulo, Brazil.

Background: Cell interactions, adherence, and osseointegration at the bone-implant interface can be directly influenced by the surface properties of the titanium implant.

Purpose: To characterize osseointegration of Neoss® implants with conventional (control group) and hydrophilic (test group) surface treatments.

Materials And Methods: Six Labrador dogs received Neoss implants with conventional and hydrophilic surfaces. The bone-implant interfaces were evaluated 1 and 4 weeks after implantation, and osseointegration was evaluated using histological, histomorphometric, fluorescence, and resonance frequency analyses. The surfaces were also subjected to topographic and hydrophilicity analyses.

Results: The topographic analyses revealed increased surface roughness in the test group compared with the control group (surface area roughness 0.42 and 0.78 μm, respectively, for control and test group surfaces; p ≤ .05). The wettability values were higher in the test group (contact angles 67.2° and 27.2° for the control and test group surfaces, respectively; p ≤ .05). Implants in the test group also exhibited better stability, more bone-implant contact, and increased bone area compared with implants in the control group.

Conclusion: Neoss implants in the test group improved bone formation in the early stages of osseointegration compared with implants in the control group.
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http://dx.doi.org/10.1111/cid.12213DOI Listing
December 2015

Bone Ceramic® at Implants Installed Immediately into Extraction Sockets in the Molar Region: An Experimental Study in Dogs.

Clin Implant Dent Relat Res 2016 Apr 7;18(2):360-8. Epub 2015 Aug 7.

Ariminum Odontologica, ARDEC, Rimini, Italy.

Purpose: The aim of this paper was to study the healing of 1-1.4 mm wide buccal defects at implants placed immediately into extraction sockets (IPIES) filled with a mixture of synthetic hydroxyapatite (HA) 60% and beta-tricalciumphosphate (TCP) 40% or left with the clot alone and both covered with collagen membranes.

Material And Methods: Eight Labrador dogs were used and implants were placed immediately into the extraction sockets of the first molar bilaterally. A mixture of synthetic HA 60% and beta-TCP 40% at the test or the clot alone at the control sites were used to fill the defects. All surgical sites were subsequently covered by a resorbable collagen membrane and a non-submerged healing was allowed. After 4 months, the animals were euthanized, biopsies harvested and processed for histomorphometric analysis.

Results: At the time of installation, residual buccal defects occurred that were 1.1 mm and 1.4 mm wide and 3 mm and 4 mm deep at the control and test sites, respectively. After 4 months of healing, the top of the bony crest and the coronal level of osseointegration were located respectively at 0.1 ± 1.8 mm and 1.5 ± 1.8 mm at the test, and 0.6 ± 1.6 mm and 1.2 ± 0.7 mm at the control sites apically to the implant shoulder. Bone-to-implant contact at the buccal aspect was 34.9 ± 25.9% and 36.4 ± 17.3% at the test and control sites, respectively. No statistically significant differences were found between test and control sites for any of the variables analyzed at the buccal aspects.

Conclusions: The use of a mixture of synthetic HA 60% and beta-TCP 40% to fill residual buccal defects 1-1.4 mm wide at IPIES did not improve significantly the results of healing.
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http://dx.doi.org/10.1111/cid.12312DOI Listing
April 2016

Fresh-frozen allografts combined with bovine bone mineral enhance bone formation in sinus augmentation.

J Biomater Appl 2015 Feb 22;29(7):1003-13. Epub 2014 Sep 22.

Department of Oral and Maxillofacial Surgery and Periodontology. Ribeirão Preto Dental School, University of São Paulo, São Paulo, Brazil

We evaluated histologically, histomorphometrically, and tomographically the effects of the association of fresh-frozen bone allograft (FFB) with bovine bone mineral (BBM) in maxillary sinus floor augmentation. In total, 34 maxillary sinuses from 29 patients, with a mean age of 51.32 (±6.44) years, underwent sinus augmentation. Patients were divided into control and test groups (17 sinuses each). The controls were grafted with allograft bone, and the test group received a combination of FFB and BBM at a 2:1 ratio. After 6 months, bone samples were collected for histological and histomorphometric examinations. The implant survival rates were 93.02% (control group) and 100% (test group) at 6 months after functional loading. Median volumetric reductions of 28.32% (17.05-44.05) and 12.62% (5.65-16.87) were observed for the control and test groups, respectively. Statistically significant histomorphometric differences were found between the control and test groups regarding newly formed bone 12.54% (10.50-13.33) vs. 24.42% (17.62-35.92), p < 0.001, total bone 48.34% (39.03-54.42) vs. 61.32% (50.61-64.96), p = 0.007, and connective tissue 51.66% (45.57-60.97) vs. 39.30% (35.03-49.37), p = 0.007. The addition of BBM to allograft bone in maxillary sinus augmentation resulted in higher percentages of new bone formation and total bone, and permitted implant placement with a low rate of osseointegration failure at the 6-month follow-up.
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http://dx.doi.org/10.1177/0885328214552709DOI Listing
February 2015

Effects of Photodynamic Process (PDP) in Implant Osseointegration: A Histologic and Histometric Study in Dogs.

Clin Implant Dent Relat Res 2015 Oct 7;17(5):879-90. Epub 2014 Feb 7.

Department of Oral and Maxillofacial Surgery and Periodontics, Faculty of Dentistry, University of São Paulo, Ribeirão Preto, Brazil.

Background: The combination between photosensitivity substances with laser or light-emitting diode (LED) form the photodynamic therapy basis that consists of photosensitivity drug activated by low-frequency light. This mechanism is used in soft tissue healing process to improve the oxygen tension leading to a fast revascularization.

Purpose: The objective of this study was to evaluate the effects of photosensitivity drugs activated through LED on osseointegration process.

Materials And Methods: Eight mongrel dogs underwent implant therapy in four mandibular bone defects using 5.0 mm trephine drill on each side of the mandible. The defects were randomly filled up with (1) Nano emulsion, (2) liposome, (3) blood clot, and (4) autogenous bone. LED with visible and infrared light were applied after 48/72 postoperative hours on four dogs and after 96/120 postoperative hours in the other four dogs. All the animals were euthanized at 15 days after surgery. Ground sections slides were prepared from the experimental site for histomorphometry and histological analysis.

Results: No difference was detected in the following parameters: bone-implant contact, bone inside the defect and crest level on LED 48/72. Significant difference was detected inside the defect when filled with autogenous bone (p = .0238) on LED 96/120. When LED 48/72 and LED 96/120 were compared, significant higher bone formation was detected when autogenous bone on bone-implant contact (p = .0043) and bone inside the defect (p = .0008) was used.

Conclusion: The use of photosensitivity drugs activated by LED demonstrated a tendency to stimulate bone formation, similar to autogenous bone graft on later time point.
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http://dx.doi.org/10.1111/cid.12204DOI Listing
October 2015

Treatment of circumferential defects with osseoconductive xenografts of different porosities: a histological, histometric, resonance frequency analysis, and micro-CT study in dogs.

Clin Implant Dent Relat Res 2015 Jan 28;17 Suppl 1:e202-20. Epub 2013 Nov 28.

University of São Paulo, Ribeirão Preto, São Paulo, Brazil.

Background: Finding the most effective method of minimizing the gap effect in alveolar crest remodeling constitutes a clinical challenge for immediate implant technique.

Purpose: To evaluate the effectiveness of osseoconductive xenografts with different porosities in the crestal bone region, with and without guided bone regeneration, over immediate implant installation.

Materials And Methods: Five bone defects (6 mm in diameter/4 mm depth) were prepared on one side of the mandibles of twelve dogs. Implants of 3.3 × 10 mm were installed on the mesial side of each defect, providing a 2.7-mm distal gap. Defects were randomly filled with autogenous bone, coagulum, a deproteinized bovine bone mineral (DBBM) block, a DBBM sponge, or DBBM granules. The same procedures were performed on the opposite side after 8 weeks. Collagen membranes were used to cover the defects on half of the sides. The animals were sacrificed after 8 weeks. The outcomes were evaluated by histology, histomorphometric analysis, resonance frequency analysis, and micro-CT analysis.

Results: The histomorphometry showed the DBBM sponge to provide similar bone formation to autogenous bone at 8 weeks without a membrane. The coagulum rendered better bone formation at 16 weeks (membrane) (p < .05). The DBBM block exhibited the poorest results between treatments (8 and 16 weeks, with or without membrane). Micro-CT analysis revealed increasing bone surface values in sites with DBBM granules, followed by the DBBM sponge (8 weeks without membrane) and autogenous bone at 8 weeks with membrane (p < .05). Porosity analysis of the biomaterials showed the highest number, volume, and surface area of closed pores in DBBM granules. The DBBM block presented the highest volume of open pores, open porosity, and total porosity.

Conclusions: The high-porosity block (DBBM block) failed to provide greater bone repair within the defect. Biomaterials with lower porosity (DBBM sponge and granules) showed similar or higher bone formation when compared with autogenous bone.
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http://dx.doi.org/10.1111/cid.12181DOI Listing
January 2015

Immunohistochemical, tomographic, and histological study on onlay bone graft remodeling. Part III: allografts.

Clin Oral Implants Res 2013 Oct 9;24(10):1164-72. Epub 2012 Jul 9.

Department of Oral and Maxillofacial Surgery, University of Sao Paulo, Ribeirao Preto, Brazil.

Objective: In the last decades aroused the interest for bone tissue bank as an alternative to autogenous grafting, avoiding donor sites morbidity, surgical time, and costs reduction. The purpose of the study was to compare allografts (ALg) with autografts (AUg) using histology, immunochemistry, and tomographic analysis.

Material And Methods: Fifty-six New Zealand White rabbits were submitted to surgical procedures. Twenty animals were donors and 36 were actually submitted to onlay grafting with ALg (experimental group) and AUg (control group) randomly placed bilaterally in the mandible. Six animals of each group were sacrificed at 3, 5, 7, 10, 20, and 60 postoperative days. Immunolabeling was accomplished with osteoprotegerin (OPG); receptor activator of nuclear factor-k ligand (RANKL); alkaline phosphatase (ALP); osteopontin (OPN); vascular endothelial growth factor (VEGF); tartrate-resistant acid phosphatase (TRAP); collagen type I (COL I); and osteocalcin (OC). Density and volume of the grafts was evaluated on tomography obtained at the surgery and sacrifice.

Results: The ALg and AUg exhibited similar patterns of density and volume throughout the experiments. The intra-group data showed statistical differences at days 7 and 60 in comparison with other time points (P = 0.001), in both groups. A slight graft expansion from fixation until day 20 (P = 0.532) was observed in the AUg group and then resorbed significantly at the day 60 (P = 0.015). ALg volume remained stable until day 7 and decreased at day 10 (P = 0.045). The light microscopy analysis showed more efficient incorporation of AUg onto the recipient bed if compared with the ALg group. The immunohistochemical labeling picked: at days 10 and 20 with OPG in the AUg group and at day 7 with TRAP in the ALg group (P = 0.001 and P = 0.002, respectively).

Conclusions: ALg and AUg were not differing in patterns of volume and density during entire experiment. Histological data exhibit more efficient AUg incorporation into recipient bed compared with the ALg group. Immunohistochemistry outcomes demonstrated similar pattern for both ALg and AUg groups, except for an increasing resorption activity in the ALg group mediated by TRAP and in the AUg group by higher OPG labeling. However, this latter observation does not seem to influence clinical outcomes.
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http://dx.doi.org/10.1111/j.1600-0501.2012.02528.xDOI Listing
October 2013

Periapical tissue response after use of intermediate restorative material, gutta-percha, reinforced zinc oxide cement, and mineral trioxide aggregate as retrograde root-end filling materials: a histologic study in dogs.

J Oral Maxillofac Surg 2012 Sep 20;70(9):2041-7. Epub 2012 Apr 20.

Maxillofacial Unit, Halmstad Hospital, Halland, Sweden.

Purpose: To investigate the periapical tissue response of 4 different retrograde root-filling materials, ie, intermediate restorative material, thermoplasticized gutta-percha, reinforced zinc oxide cement (Super-EBA), and mineral trioxide aggregate (MTA), in conjunction with an ultrasonic root-end preparation technique in an animal model.

Materials And Methods: Vital roots of the third and fourth right mandibular premolars in 6 healthy mongrel dogs were apicectomized and sealed with 1 of the materials using a standardized surgical procedure. After 120 days, the animals were sacrificed and the specimens were analyzed radiologically, histologically, and scanning electron microscopically. The Fisher exact test was performed on the 2 outcome values.

Results: Twenty-three sections were analyzed histologically. Evaluation showed better re-establishment of the periapical tissues and generally lower inflammatory infiltration in the sections from teeth treated with the intermediate restorative material and the MTA. New root cement on the resected dentin surfaces was seen on all sections regardless of the used material. New hard tissue formation, directly on the surface of the material, was seen only in the MTA sections. There was no statistical difference in outcome among the tested materials.

Conclusions: The results from this dog model favor the intermediate restorative material and MTA as retrograde fillings when evaluating the bone defect regeneration. MTA has the most favorable periapical tissue response when comparing the biocompatibility of the materials tested.
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http://dx.doi.org/10.1016/j.joms.2012.01.033DOI Listing
September 2012

Short implants (6 mm) installed immediately into extraction sockets: an experimental study in dogs.

Clin Oral Implants Res 2012 May 9;23(5):536-41. Epub 2012 Feb 9.

Faculty of Dentistry, University of Medical Science, La Habana, Cuba.

Aim: To evaluate the effect of implant length (6 mm vs.11 mm) on osseointegration (bone-to-implant contact) of implants installed into sockets immediately after tooth extraction.

Material And Methods: In six Labrador dogs, the pulp tissue of the mesial roots of (3) P(3) was removed and the root canals were filled. Flaps were elevated bilaterally, the premolars hemi-sectioned and the distal roots removed. Recipient sites were prepared in the distal alveolus and a 6 mm or an 11 mm long implant was installed at the test and control sites, respectively. Non-submerged healing was allowed. After 4 months of healing, block sections of the implant sites were obtained for histological processing and peri-implant tissue assessment.

Results: No statistically significant differences were found between test and control sites both for hard and soft tissue parameters. The bone-to-implant contact evaluated at the apical region of the implants was similar as well. Although not statistically significant, the location of the top of the bony crest at the buccal aspect was more apical in relation to the implant shoulder at the test compared with the control sites (2.0 ± 1.4 and 1.2 ± 1.1 mm, respectively).

Conclusions: Shorter implants (6 mm) present with equal osseointegration than do longer implants (11 mm).
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http://dx.doi.org/10.1111/j.1600-0501.2012.02432.xDOI Listing
May 2012

Bone healing pattern in surgically created circumferential defects around submerged implants: an experimental study in dog.

Clin Oral Implants Res 2012 Jan 28;23(1):41-8. Epub 2011 Mar 28.

UNESP - Faculty of Dentistry of Araçatuba, São Paulo State University, São Paulo, Brazil.

Objective: To describe the healing of marginal defects below or above 1 mm of dimension around submerged implants in a dog model.

Material And Methods: In 12 Labrador dogs, all mandibular premolars and first molars were extracted bilaterally. After 3 months of healing, full-thickness flaps were elevated in the edentulous region of the right side of the mandible. Two recipient sites were prepared and the marginal 5 mm were widened to such an extent to obtain, after implant installation, a marginal gap of 0.5 mm at the mesial site (small defect) and of 1.25 mm at the distal site (large defect). Titanium healing caps were affixed to the implants and the flaps were sutured allowing a fully submerged healing. The experimental procedures were subsequently performed in the left side of the mandible. The timing of the experiments and sacrifices were planned in such a way to obtain biopsies representing the healing after 5, 10, 20 and 30 days. Ground sections were prepared and histomorphometrically analyzed.

Results: The filling of the defect with newly formed bone was incomplete after 1 month of healing in all specimens. Bone formation occurred from the base and the lateral walls of the defects. A larger volume of new bone was formed in the large compared with the small defects. Most of the new bone at the large defect was formed between the 10- and the 20-day period of healing. After 1 month of healing, the outline of the newly formed bone was, however, located at a similar distance from the implant surface (about 0.4 mm) at both defect types. Only minor newly formed bone in contact with the implant, starting from the base of the defects, was seen at the large defects (about 0.8 mm) while a larger amount was detected at the small defects (about 2.2 mm).

Conclusion: Marginal defects around titanium implants appeared to regenerate in 20-30 days by means of a distance osteogenesis. The bone fill of the defects was, however, incomplete after 1 month.
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http://dx.doi.org/10.1111/j.1600-0501.2011.02170.xDOI Listing
January 2012

Tomographic, histological, and immunohistochemical evidences on the use of N-butyl-2-cyanoacrilate for onlay graft fixation in rabbits.

Clin Implant Dent Relat Res 2012 Dec 22;14(6):861-71. Epub 2010 Dec 22.

Department of Oral and Maxillofacial Surgery and Periodontics, Faculty of Dentistry of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, SP, Brazil.

Background: The bone tissue responses to Cyanoacrylate have been described in the literature, but none used N-butyl-2-cyanoacrilate (NB-Cn) for bone graft fixation.

Purpose: The aims of the study were: (a) to analyze the bone grafts volume maintenance fixed either with NB-Cn or titanium screw; (b) to assess the incorporation of onlay grafts on perforated recipient bed; and (c) the differences of expression level of tartrate-resistant acid phosphatase (TRAP) protein involved in bone resorption.

Materials And Methods: Eighteen New Zealand White rabbits were submitted to calvaria onlay grafting on both sides of the mandible. On one side, the graft was fixed with NB-Cn, while on the other hand the bone graft was secured with an osteosynthesis screw. The computed tomography (CT) was performed just after surgery and at animals sacrifice, after 1 (n = 9) and 6 weeks (n = 9), in order to estimate the bone grafts volume along the experiments. Histological sections of the grafted areas were prepared to evaluate the healing of bone grafts and to assess the expression of TRAP protein.

Results: The CT scan showed better volume maintenance of bone grafts fixed with NB-Cn (p ≤ 0.05) compared with those fixed with screws, in both experimental times (analysis of variance). The immunohistochemical evaluation showed that the TRAP expression in a 6-week period was significantly higher compared with the 1-week period, without showing significant difference between the groups (Wilcoxon and Mann-Whitney). Histological analysis revealed that the NB-Cn caused periosteum damage, but provided bone graft stabilization and incorporation similar to the control group.

Conclusion: The perforation provided by screw insertion into the graft during fixation may have triggered early revascularization and remodeling to render increased volume loss compared with the experimental group. These results indicate that the NB-Cn possesses equivalent properties to titanium screw to be used as bone fixation material in osteosynthesis.
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http://dx.doi.org/10.1111/j.1708-8208.2010.00321.xDOI Listing
December 2012

Magnesium-enriched hydroxyapatite at immediate implants: a histomorphometric study in dogs.

Clin Oral Implants Res 2011 May 9;22(5):512-7. Epub 2010 Dec 9.

UNESP - Faculty of Dentistry of Araçatuba, São Paulo State University, Brazil.

Aim: To evaluate the influence of magnesium-enriched hydroxyapatite (MHA) (SintLife(®)) on bone contour preservation and osseointegration at implants placed immediately into extraction sockets.

Material And Methods: In the mandibular pre-molar region, implants were installed immediately into extraction sockets of six Labrador dogs. MHA was placed at test sites, while the control sites did not receive augmentation materials. Implants were intended to heal in a submerged mode. After 4 months of healing, the animals were sacrificed, and ground sections were obtained for histomorphometric evaluation.

Results: After 4 months of healing, one control implant was not integrated leaving n=5 test and control implants for evaluation. Both at the test and the control sites, bone resorption occurred. While the most coronal bone-to-implant contact was similar between test and control sites, the alveolar bony crest outline was maintained to a higher degree at the buccal aspect of the test sites (loss: 0.7 mm) compared with the control sites (loss: 1.2 mm), even though this difference did not reach statistical significance.

Conclusions: The use of MHA to fill the defect around implants placed into the alveolus immediately after tooth extraction did not contribute significantly to the maintenance of the contours of the buccal alveolar bone crest.
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http://dx.doi.org/10.1111/j.1600-0501.2010.02040.xDOI Listing
May 2011

Flap vs. "flapless" surgical approach at immediate implants: a histomorphometric study in dogs.

Clin Oral Implants Res 2010 Dec;21(12):1314-9

UNESP, Faculty of Dentistry of Araçatuba (SP), São Paulo State University, São Paulo, SP, Brazil.

Aim: To compare the remodeling of the alveolar process at implants installed immediately into extraction sockets by applying a flap or a "flapless" surgical approach in a dog model.

Material And Methods: Implants were installed immediately into the distal alveoli of the second mandibular premolars of six Labrador dogs. In one side of the mandible, a full-thickness mucoperiosteal flap was elevated (control site), while contra-laterally, the mucosa was gently dislocated, but not elevated (test site) to disclose the alveolar crest. After 4 months of healing, the animals were sacrificed, ground sections were obtained and a histomorphometric analysis was performed.

Results: After 4 months of healing, all implants were integrated (n=6). Both at the test and at the control sites, bone resorption occurred with similar outcomes. The buccal bony crest resorption was 1.7 and 1.5 mm at the control and the test sites, respectively.

Conclusions: "Flapless" implant placement into extraction sockets did not result in the prevention of alveolar bone resorption and did not affect the dimensional changes of the alveolar process following tooth extraction when compared with the usual placement of implants raising mucoperiosteal flaps.
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http://dx.doi.org/10.1111/j.1600-0501.2010.01959.xDOI Listing
December 2010

Influence of lateral pressure to the implant bed on osseointegration: an experimental study in dogs.

Clin Oral Implants Res 2010 Nov;21(11):1264-70

Faculty of Dentistry of Araçatuba, UNESP - São Paulo State University, São Paulo, Brazil.

Aim: To study osseointegration and bone-level changes at implants installed using either a standard or a reduced diameter bur for implant bed preparation.

Material And Methods: In six Labrador dogs, the first and second premolars were extracted bilaterally. Subsequently, mesial roots of the first molars were endodontically treated and distal roots, including the corresponding part of the crown, were extracted. After 3 months of healing, flaps were elevated and recipient sites were prepared in all experimental sites. The control site was prepared using a standard procedure, while the test site was prepared using a drill with a 0.2 mm reduced diameter than the standard one used in the contra-lateral side. After 4 months of healing, the animals were euthanized and biopsies were obtained for histological processing and evaluation.

Results: With the exception of one implant that was lost, all implants were integrated in mineralized bone. The alveolar crest underwent resorption at control as well as at test sites (buccal aspect ∼1 mm). The most coronal contact of bone-to-implant was located between 1.2 and 1.6 mm at the test and between 1.3 and 1.7 mm at the control sites. Bone-to-implant contact percentage was between 49% and 67%. No statistically significant differences were found for any of the outcome variables.

Conclusions: After 4 months of healing, lateral pressure to the implant bed as reflected by higher insertion torques (36 vs. 15 Ncm in the premolar and 19 vs. 7 Ncm in the molar regions) did not affect the bone-to-implant contact.
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http://dx.doi.org/10.1111/j.1600-0501.2010.01941.xDOI Listing
November 2010

Collagen membranes at immediate implants: a histomorphometric study in dogs.

Clin Oral Implants Res 2010 Sep 24;21(9):891-7. Epub 2010 May 24.

UNESP - Faculty of Dentistry of Araçatuba, São Paulo State University, SP, Brazil.

Aim: To evaluate the influence of resorbable membranes on hard tissue alterations and osseointegration at implants placed into extraction sockets in a dog model.

Material And Methods: In the mandibular premolar region, implants were installed immediately into the extraction sockets of six Labrador dogs. Collagen-resorbable membranes were placed at the test sites, while the control sites were left uncovered. Implants were intended to heal in a submerged mode. After 4 months of healing, the animals were sacrificed, and ground sections were obtained for histomorphometric evaluation.

Results: After 4 months of healing, a control implant was not integrated (n=5). Both at the test and at the control sites, bone resorption occurred. While the most coronal bone-to-implant contact was similar between the test and the control sites, the alveolar bone crest outline was maintained to a higher degree at the buccal aspect of the test sites (loss: 1.7 mm) compared with the control sites (loss: 2.2 mm).

Conclusions: The use of collagen-resorbable membranes at implants immediately placed into extraction sockets contributed to a partial (23%) preservation of the buccal outline of the alveolar process.
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http://dx.doi.org/10.1111/j.1600-0501.2010.01946.xDOI Listing
September 2010

Hard tissue formation adjacent to implants of various size and configuration immediately placed into extraction sockets: an experimental study in dogs.

Clin Oral Implants Res 2010 Sep 9;21(9):885-90. Epub 2010 May 9.

UNESP - Faculty of Dentistry of Araçatuba, São Paulo State University, Sao Paulo, Brazil.

Objectives: To evaluate the influence of implant size and configuration on osseointegration in implants immediately placed into extraction sockets.

Material And Methods: Implants were installed immediately into extraction sockets in the mandibles of six Labrador dogs. In the control sites, cylindrical transmucosal implants (3.3 mm diameter) were installed, while in the test sites, larger and conical (root formed, 5 mm diameter) implants were installed. After 4 months of healing, the resorptive patterns of the alveolar crest were evaluated histomorphometrically.

Results: With one exception, all implants were integrated in mineralized bone, mainly composed of mature lamellar bone. The alveolar crest underwent resorption at the control as well as at the test implants. This resorption was more pronounced at the buccal aspects and significantly greater at the test (2.7+/-0.4 mm) than at the control implants (1.5+/-0.6 mm). However, the control implants were associated with residual defects that were deeper at the lingual than at the buccal aspects, while these defects were virtually absent at test implants.

Conclusions: The installment of root formed wide implants immediately into extraction sockets will not prevent the resorption of the alveolar crest. In contrast, this resorption is more marked both at the buccal and lingual aspects of root formed wide than at standard cylindrical implants.
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http://dx.doi.org/10.1111/j.1600-0501.2010.01931.xDOI Listing
September 2010

Influence of implant positioning in extraction sockets on osseointegration: histomorphometric analyses in dogs.

Clin Oral Implants Res 2010 Jan;21(1):43-9

Faculty of Dentistry of Araçatuba (SP), University of the State of São Paulo, Brazil.

Aim: To evaluate the influence of implant positioning into extraction sockets on osseointegration.

Material And Methods: Implants were installed immediately into extraction sockets in the mandibles of six Labrador dogs. In the control sites, the implants were positioned in the center of the alveolus, while in the test sites, the implants were positioned 0.8 mm deeper and more lingually. After 4 months of healing, the resorptive patterns of the alveolar crest were evaluated histomorphometrically.

Results: All implants were integrated in mineralized bone, mainly composed of mature lamellar bone. The alveolar crest underwent resorption at the control as well as at the test sites. After 4 months of healing, at the buccal aspects of the control and test sites, the location of the implant rough/smooth limit to the alveolar crest was 2 + or - 0.9 mm and 0.6 + or - 0.9 mm, respectively (P<0.05). At the lingual aspect, the bony crest was located 0.4 mm apically and 0.2 mm coronally to the implant rough/smooth limit at the control and test sites, respectively (NS).

Conclusions: From a clinical point of view, implants installed into extraction sockets should be positioned approximately 1 mm deeper than the level of the buccal alveolar crest and in a lingual position in relation to the center of the alveolus in order to reduce or eliminate the exposure above the alveolar crest of the endosseous (rough) portion of the implant.
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http://dx.doi.org/10.1111/j.1600-0501.2009.01842.xDOI Listing
January 2010

Implant osseointegration in circumferential bone defects treated with latex-derived proteins or autogenous bone in dog's mandible.

Clin Implant Dent Relat Res 2012 Mar 29;14(1):135-43. Epub 2009 Sep 29.

Department of Oral and Maxillofacial Surgery and Periodontics, Faculty of Dentistry of Ribeirao Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.

Background: In sites with diminished bone volume, the osseointegration of dental implants can be compromised. Innovative biomaterials have been developed to aid successful osseointegration outcomes.

Purpose: The aim of this study was to evaluate the osteogenic potential of angiogenic latex proteins for improved bone formation and osseointegration of dental implants.

Materials And Methods: Ten dogs were submitted to bilateral circumferential defects (5.0 × 6.3 mm) in the mandible. Dental implant (3.3 × 10.0 mm, TiUnite MK3™, Nobel Biocare AB, Göteborg, Sweden) was installed in the center of the defects. The gap was filled either with coagulum (Cg), autogenous bone graft (BG), or latex angiogenic proteins pool (LPP). Five animals were sacrificed after 4 weeks and 12 weeks, respectively. Implant stability was evaluated using resonance frequency analysis (Osstell Mentor, Osstell AB, Göteborg, Sweden), and bone formation was analyzed by histological and histometric analysis.

Results: LPP showed bone regeneration similar to BG and Cg at 4 weeks and 12 weeks, respectively (p ≥ .05). Bone formation, osseointegration, and implant stability improved significantly from 4 to 12 weeks (p ≤ .05).

Conclusion: Based on methodological limitations of this study, Cg alone delivers higher bone formation in the defect as compared with BG at 12 weeks; compared with Cg and BG, the treatment with LPP exhibits no advantage in terms of osteogenic potential in this experimental model, although overall osseointegration was not affected by the treatments employed in this study.
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http://dx.doi.org/10.1111/j.1708-8208.2009.00238.xDOI Listing
March 2012

Immunohistochemical, tomographic and histological study on onlay bone graft remodeling. Part II: calvarial bone.

Clin Oral Implants Res 2009 Nov 15;20(11):1254-64. Epub 2009 Jun 15.

Department of Oral and Maxillofacial Surgery and Periodontics, Faculty of Dentistry of Ribeirão Preto, University of São Paulo at Ribeirão Preto, SP, Brazil.

Objectives: Little information is available on the molecular events that occur during graft incorporation over time. The calvarial bone (Cb) grafts have been reported to produce greater responses compared with other donor regions in maxillofacial reconstructions, but the scientific evidences for this are still lacking. The objectives of this study are (1) to study the morphological pattern of Cb onlay bone grafts and compare them with the biological events through immunohistochemical responses and (2) to establish the effects of perforations in maintaining the volume and bone density of the receptor bed.

Material And Methods: Sixty New Zealand White rabbits were submitted to Cb onlay bone grafts on the mandible. In 30 rabbits, the receptor bed was perforated (perforated group), while for the remaining animals the bed was kept intact (non-perforated group). Six animals from each group were sacrificed at 5, 7, 10, 20 and 60 days after surgery. Histological sections from the grafted area were prepared for immunohistochemical and histological analyses. Immuno-labeling was found for proteins Osteoprotegerin (OPG), receptor activator of nuclear factor-kappabeta ligand (RANKL), alkaline phosphatase (ALP), osteopontin (OPN), vascular endothelial growth factor (VEGF), tartrate-resistant acid phosphatase (TRAP), Type I collagen (COL I) and osteocalcin (OC). The tomography examination [computerized tomography (CT) scan] was conducted just after surgery and at the sacrifice.

Results: The histological findings revealed that the perforations contributed to higher bone deposition during the initial stages at the graft-receptor bed interface, accelerating the graft incorporation process. The results of the CT scan showed lower resorption for the perforated group (P
Conclusions: These findings indicate that the bone volume of calvarial grafts is better maintained when the receptor bed is perforated, probably resulting from more effective graft revascularization and greater bone deposition. The process of bone resorption peaked between 20 and 60 days post-operatively in both groups although significantly less in the perforated group.
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http://dx.doi.org/10.1111/j.1600-0501.2009.01747.xDOI Listing
November 2009

Bone formation following implantation of titanium sponge rods into humeral osteotomies in dogs: a histological and histometrical study.

Clin Implant Dent Relat Res 2010 Mar 3;12(1):72-9. Epub 2008 Dec 3.

Department of Oral & Maxillofacial Surgery, Faculty of Dentistry of Araçatuba, University of São Paulo, Campus USP 14040-904 Ribeirão Preto, São Paulo, Brazil.

Background: Titanium (Ti) is widely proven to enhance bone contact and growth on its surface. It is expected that bone defects could benefit from Ti to promote healing and to increase strength of the implanted area.

Purpose: The present study aimed at comparing the potential of porous Ti sponge rods with synthetic hydroxyapatite (HA) for the healing of bone defects in a canine model.

Material And Methods: Six mongrel dogs were submitted to three trephined osteotomies of 6.0 x 4.0 mm in one humerus and after 2 months another three osteotomies were performed in the contralateral humerus. A total of 36 defects were randomly filled either with Ti foam, particulate HA, or coagulum (control). The six animals were killed 4 months after the first surgery for histological and histometrical analysis.

Results: The Ti-foam surface was frequently found in intimate contact with new bone especially at the defect walls. Control sites showed higher amounts of newly formed bone at 2 months - Ti (p = 0.000) and HA (p = 0.009) - and 4 months when compared with Ti (p = 0.001). Differently from HA, the Ti foam was densely distributed across the defect area which rendered less space for bone growth in the latter's sites. The use of Ti foams or HA resulted in similar amounts of bone formation in both time intervals. Nevertheless, the presence of a Ti-foam rod preserved defect's marginal bone height as compared with control groups. Also, the Ti-foam group showed a more mature bone pattern at 4 months than HA sites.

Conclusion: The Ti foam exhibited good biocompatibility, and its application resulted in improved maintenance of bone height compared with control sites. The Ti foam in a rod design exhibited bone ingrowth properties suitable for further exploration in other experimental situations.
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http://dx.doi.org/10.1111/j.1708-8208.2008.00132.xDOI Listing
March 2010

Intraosseous schwannoma of mandibular symphysis: case report.

Braz Dent J 2006 ;17(3):255-8

Department of Morphology, Stomatology and Physiology, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.

Schwannoma (neurilemmoma) is a benign neoplasm originated from the neural sheath and occurring most frequently in the head and neck. Intraosseous schwannomas are rare. The mandible is the most common site of occurrence for these lesions. This article reports the case of an intraosseous schwannoma located in the mandibular symphysis of an 11-year-old boy. The lesion was surgically removed and no radiographic evidence of recurrence was observed after 5 years.
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http://dx.doi.org/10.1590/s0103-64402006000300015DOI Listing
March 2007

Histomorphometric analysis of rat alveolar wound healing with hydroxyapatite alone or associated to BMPs.

Braz Dent J 2002 ;13(3):147-54

Department of Bucco-Maxillo-Facial Surgery and Traumatology and Periodontology, Faculty of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.

Several materials and techniques have been proposed to improve alveolar wound healing and decrease loss of bone height and thickness that normally follow dental extraction. The objective of this research was the histologic analysis of bone morphogenetic proteins implanted into dental alveoli of rats after extraction. A total of 45 adult male Wistar rats were divided into three groups of 15 animals each: control (no treatment), implanted with pure hydroxyapatite (HA, 3 mg) and implanted with hydroxyapatite plus bone morphogenetic proteins (HA/BMPs, 3 mg). Five animals from each group were sacrificed at 7, 21 and 42 days after extraction for the histometric analyses of the osteoconductive potential of hydroxyapatite associated or not with BMPs. After dissection, fixation, decalcification and serial microtomy of 6-micron thick sections, the samples were stained with hematoxylin-eosin for histologic and histometric analyses. Both HA and HA/BMPs caused a delay in wound healing compared to control animals, evaluated by the percentage of bone tissue in the alveoli. The treatment with HA/BMPs had the greatest delay at 21 days, even though it produced values similar to the control group at 42 days. The materials did not improve alveolar repair in the normal period of wound healing and the association of HA/BMPs did not have osteoconductive properties with granulated hydroxyapatite as the vehicle.
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http://dx.doi.org/10.1590/s0103-64402002000300001DOI Listing
February 2003