Biomedical subjects

Gabriele Pecora

Publications and source records attributed to Gabriele Pecora.

9 recordsLinked to original sources

PubMed2006

Maxillary sinus augmentation with different biomaterials: a comparative histologic and histomorphometric study in man.

OBJECTIVE: Rehabilitation of the edentulous posterior maxilla with dental implants can be difficult because of insufficient bone volume caused by pneumatization of the maxillary sinus and crestal bone resorption. Different biomaterials have been used for sinus augmentation. The aim of the study was to compare different materials in maxillary sinus augmentation in man. METHODS: A total of 94 patients participated in this study. Inclusion criteria were maxillary partial (unilateral or bilateral) edentulism involving the premolar/molar areas, and the presence of 3-5-mm crestal bone between the sinus floor and alveolar ridge. A total of 362 implants were inserted. There were 9 biomaterials used in the sinus augmentation procedures. Each patient underwent 1 biopsy after 6 months. A total of 144 specimens were retrieved. RESULTS: None of the 94 patients had complications. All implants were stable, and x-ray examination showed dense bone around the implants. Mean follow-up was 4 years. There were 7 implants that failed. Histologic resultsshowed that almost all the particles of the different biomaterials (i.e., autologous bone, demineralized freeze-dried bone allograft Biocoral [Inoteb, St. Gonnery, France], Bioglass [US Biomaterials, Alachua, FL], Fisiograft [Ghimas, Bologna, Italy], PepGen P-15 [Dentsply Friadent CeraMed, Lakewood, CO], calcium sulfate, Bio-Oss [Geistlich Pharma AG, Wohlhusen, Switzerland], and hydroxyapatite) were surrounded by bone. Some biomaterials were more resorbable than others. Included are the histomorphometry clarified features of the newly formed bone around the different grafted particles. CONCLUSION: All biomaterials examined resulted in being biocompatible and seemed to improve new bone formation in maxillary sinus lift. No signs of inflammation were present. The data are very encouraging because of the high number of successfully treated patients and the good quality of bone found in the retrieved specimens.

Aged↗

PubMed2006

Histologic evaluation of 3 retrieved immediately loaded implants after a 4-month period.

OBJECTIVE: To perform a histologic and histomorphometric analysis of the peri-implant tissue reactions and bone-titanium interface in 3 immediately loaded (provisional loaded) titanium implants retrieved from a man after a loading period of 4 months. MATERIALS & METHODS: A 35-year-old patient with a maxillary partial edentulism did not want to wear a provisional removable prosthesis during the healing period. It was decided to insert 3 definitive implants and use 3 provisional implants for the transitional period. The provisional implants were loaded the same day with a resin prosthesis in occlusal contact. During the second surgical phase, after 4 months, the provisional prosthesis was removed, and the provisional implants were retrieved with a trephine bur. Before retrieval, all implants appeared to be clinically osseointegrated. The specimens were processed for observation under light microscopy. RESULTS: At low magnification, it was possible to observe that bone trabeculae were present around the implant. Areas of bone remodeling and haversian systems were present near the implant surface. Under polarized-light microscopy, it was possible to observe that in the coronal aspect of the thread, the lamellar bone showed lamellae that tended to run parallel to the implant surface, while in the inferior aspect of the thread, the bone lamellae ran perpendicular to the implant surface. CONCLUSIONS: Histologic data pertaining to these 3 immediately loaded implants, and retrieved after a 4-month loading period, show that immediate loading did not produce untoward effects on peri-implant bone healing.

Adult↗

PubMed2006

Preferred collagen fiber orientation human peri-implant bone after a short- and long-term loading period: a case report.

Immediate loading of dental implants offers treatment cost advantages to patients and avoids the functional and psychological problems caused by the wearing of provisional dentures. There is evidence that the amount of transverse collagen fiber orientation in bone is influenced by mechanical stresses and strains. Two osseointegrated dental implants in humans were used in the present study. Two implants inserted in the maxilla were analyzed: 1 short-term implant (implant A) immediately loaded and retrieved after 4 months of loading and 1 long-term implant (implant B) immediately loaded and retrieved after 12 years. We hypothesized that the bone functional strain caused by immediate loading correlated well with the collagen fiber organization occurring after both short- and long-term functional healing. Circularly polarized light (CPL) was used to assess the area fraction extension related to the transverse collagen fiber orientation in the bone matrix. After evaluating a total of 68 digitized images taken at x50 magnification, birefringence measurements were performed all around the implant surfaces by using 2 central sections from each implant. The results showed that the bone-to-implant contact (BIC) percentage for implant A was 67.9% +/- 9.5% (mean +/- SD), whereas the BIC percentage for implant B was 74.6% +/- 11.2% (mean +/- SD). The area fraction extension was 2.7% +/- 1.4 % (mean +/- SD) for implant A, whereas the area fraction extension was 4.7% +/- 1.2% (mean +/- SD) for implant B. The CPL measurements of the birefringence for transverse collagen fibers of implant A vs implant B indicated that the bone fraction area difference was not high. In the bone near both dental implants, no differences were found in the amount of transverse collagen fibers. Immediate loading seemed to determine and maintain the collagen fiber's orientation over a long period.

Adult↗

PubMed2006

Maxillary sinus augmentation using granular calcium sulfate (surgiplaster sinus): radiographic and histologic study at 2 years.

The main goal of sinus augmentation is the formation of vital bone to allow tissue integration of endosseous implants to support prosthetic rehabilitation. The aim of the present investigation was to evaluate the radiographic and histologic results when granular medical-grade calcium sulfate hemihydrate was used as a grafting material in sinuses. Forty implants plus grafting material were placed in 10 patients, representing 15 sinuses, using a one-stage technique. Radiographs were taken prior to sinus augmentation, monthly until 6 months postoperatively, 9 and 12 months after implant placement, and annually thereafter. Bone biopsies were harvested from all patients for histologic and histomorphometric evaluation.

Alveolar Process↗

PubMed2004

Bone-defect healing with calcium-sulfate particles and cement: an experimental study in rabbit.

Calcium sulfate (CaS) has been shown to be a reasonable alternative to autogenous bone graft for treating bone lesions in dentistry. The aim of this work was an histological study of the bone healing of defects treated with calcium sulfate in the form of cement or beads, in animal. Eight New Zealand rabbits, weighing about 2.5 Kg were used in this study. In each rabbit, four 6 mm bone defects were created in the tibial metaphysis. The 2 defects in the right tibia were filled with calcium sulfate as cement, while the 2 defects in the left one were filled with calcium sulfate as beads. Four rabbits were killed after respectively 2 and 4 weeks, with an intravenous injection of Tanax, and the block sections, containing the bone defects, were retrieved. A total of 16 defects filled by cement and a total of 16 defects filled by beads were retrieved. The specimens were processed to obtain thin ground sections with the Precise 1 Automated System. In the first phases of healing it was possible to observe an intense osteoblastic activity, and in some areas osteoid matrix was present. After two weeks the calcium sulfate (both cement and beads) was still present, and biological fluids and cells were present inside the material. Newly formed bone surrounded the calcium sulfate and filled about 10% of the defect. After four weeks the calcium sulfate was almost completely resorbed and substituted by new bone. Approximately 34% of the defects were filled by newly formed bone. BEI and XRM evaluations showed the structural components of the filled defects. In none of the specimens were inflammatory cells present. No significant differences were found using both calcium sulfate as cement and beads, and they both have shown a high biocompatibility, appearing to promote newly bone formation in the rabbit model, and they did not induce any untoward effect on the bone regeneration processes.

Absorptiometry, Photon↗

PubMed2004

Medical grade calcium sulfate hemihydrate in healing of human extraction sockets: clinical and histological observations at 3 months.

BACKGROUND: Following tooth extraction, remodeling and resorption of the alveolar bone at the extraction site characterize wound healing. This produces a reduction in ridge volume and difficulties in delayed placement of implants in an ideal position. Medical grade calcium sulfate hemihydrate (MGCSH) has been proposed as a graft material in extraction sockets to minimize the reduction in ridge volume. The aim of the present study was to investigate the influence of MGCSH on the histopathologic pattern of intrasocket regenerated bone and to evaluate histologically the healed MGCSH grafted extraction socket site 3 months postextraction METHODS: MGCSH was grafted in 10 fresh human extraction sockets in 10 patients. Five post-extraction sockets were used as controls. At 3 months a cylindrical tissue specimen, 2.5 mm in diameter, was trephined from the previously grafted site followed by implant placement. Non-decalcified specimens were sectioned at a cross-horizontal plane and stained with fast green, toluidine blue, and Van Kossa stains for histological and histomorphometrical examination. RESULTS: Histologically, MGCSH was not observed in most of the specimens. Newly formed bone with lamellar arrangements was identified in all the horizontal sections with no difference between apical, medium, and coronal areas. The mean trabecular area in the coronal sections was 58.6% +/- 9.2%; in the medium sections, 58.1% +/- 6.2%; and in the apical sections, 58.3% +/- 7.8%. The differences were not statistically significant. CONCLUSION: MGCSH seems to be an ideal graft material in extraction socket bone regeneration because it is almost completely resorbable, and it allows a new trabecular bone arrangement at 3 months.

Adult↗

PubMed2004

Osseointegration in a sinus augmented with bovine porous bone mineral: histological results in an implant retrieved 4 years after insertion. A case report.

BACKGROUND: A subject of controversy in implant dentistry is what is the most appropriate material for sinus augmentation. Little is known about the healing pattern and the osseointegration processes at the interface of implants placed in different grafting materials in man. Bovine porous bone mineral (BPBM) is a xenogenic material similar to human cancellous bone with a high biocompatibility and osteoconductivity. METHODS: A 50-year-old patient presented a posterior left maxilla with an insufficient bone height for implant insertion. In January 1999, a sinus lifting procedure was performed and the left sinus was augmented with BPBM; in November 1999, three implants were inserted, and in July 2000 a fixed prosthetic restoration was positioned. In June 2003 the connecting screw of the middle implant fractured and it was decided to remove the implant using a 5 mm trephine bur. RESULTS: All BPBM particles were surrounded by newly formed bone. No BPBM particle was in direct contact with the implant surface, and between the implant surface and the particles there was newly-formed bone. BPBM seemed to undergo a very slow resorption; the particles constituted 36% +/- 3% of the peri-implant tissues. The bone-implant contact percentage was 72% +/- 4%. CONCLUSIONS: In our specimens, we found an intimate, direct contact between bone and implant without an interposition of the graft material particles. A very high bone-to-implant contact percentage was present. Our results show that the slow resorption of the graft particles did not jeopardize the osseointegration of the implant.

Animals↗

PubMed2002

Bone regeneration with calcium sulfate: evidence for increased angiogenesis in rabbits.

Autologous bone is the preferred bone graft material because it carries proteins as bone-enhancing substrates, minerals, and vital bone cells. Calcium sulfate (CS) is a well-tolerated, biodegradable, osteoconductive bone graft substitute and is a reasonable alternative to autogenous bone graft. Blood vessels are an important component of bone formation and maintenance. The process of vascular induction is called angiogenesis, and it plays a key role in all regenerative processes. Bone tissue differentiation is related to the local presence of blood vessels. One method to evaluate the presence of blood vessels in a tissue is to count the microvessels to evaluate microvessel density (MVD). The aim of the present study was to conduct a comparative evaluation of microvessel density in sites treated with CS and autologous bone in rabbits, with or without e-PTFE nonresorbable membranes (Gore-Tex, Flagstaff, Ariz). Nine New Zealand rabbits, each weighing about 2.5 kg, were used in this experiment. Three 6-mm wide defects were created in each tibial metaphysis. The defects were filled in a random way. The defects of group 1 (3 rabbits) were filled with CS granules (Surgiplaster, Classimplant, Rome, Italy) and covered with e-PTFE membranes. The defects in group 2 (3 rabbits) were filled with CS granules (Surgiplaster). The defects in group 3 (3 rabbits) were filled with autologous bone. A total of 54 defects were filled (18 with CS and e-PTFE membranes, 18 with CS alone, and 18 with autologous bone). No postoperative deaths or complications occurred. All nine animals were sacrificed at 4 weeks. MVD results were as follows: in the first group, 9.88 +/- 4.613; in the second group, 7.92 +/- 1.998; and in the third group, 5.56 +/- 1.895. P = .000 was highly significant. Statistically significant differences were found between groups 1 and 3, 1 and 2, and 2 and 3. The presence of more blood vessels in the sites treated with CS could help to explain the good results reported in the literature with the use of CS.

Analysis of Variance↗

PubMedDate not supplied

Medial-grade calcium sulfate hemihydrate (surgiplaster) in healing of a human extraction socket--histologic observation at 3 months: a case report.

PURPOSE: Following tooth extraction, wound healing is characterized by remodeling and resorption of the alveolar bone at the extraction site. This produces reduction in ridge volume. Medical-grade calcium sulfate hemihydrate (MGCSH) has been proposed as a graft material for extraction sockets to minimize the reduction in ridge volume. The aim of this study was to investigate the influence of MGCSH on the histopathologic pattern of intrasocket regenerated bone and to evaluate histologically the healed MGCSH-grafted extraction socket site at 3 months postextraction. MATERIALS AND METHODS: MGCSH was grafted in a fresh human extraction socket, and at 3 months a cylindric tissue specimen, 2.5 mm in diameter, was trephined from the previously grafted site and an implant was placed. Non-decalcified specimens were sectioned at a horizontal plane and stained for histologic and histomorphometric evaluation. RESULTS: The mean trabecular area was 58.6% +/- 9.2% in the coronal sections, 58.1% +/- 6.2% in the middle sections, and 58.3% +/- 7.8% in the apical sections. The differences in mean trabecular area between sections were not statistically significant. DISCUSSION: It is significant that the MGCSH underwent complete resorption and replacement by newly formed bone because the most important negative attribute of other graft materials is the resorption time. Moreover, calcium sulfate shows great potential for guided bone regeneration in surgical sites. CONCLUSION: MGCSH seems to be an acceptable graft material for extraction socket bone regeneration because it is completely resorbable and allows new trabecular bone arrangement in a limited 3-month period.

Alveolar Bone Loss↗