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Biomedical subjects

Adriano Piattelli

Publications and source records attributed to Adriano Piattelli.

At least 109 records · Page 6Linked to original sources
PubMed2003

Bone contact around acid-etched implants: a histological and histomorphometrical evaluation of two human-retrieved implants.

The surface characteristics of dental implants play an important role in their clinical success. One of the most important surface characteristics of implants is their surface topography or roughness. Many techniques for preparing dental implant surfaces are in clinical use: turning, plasma spraying, coating, abrasive blasting, acid etching, and electropolishing. The Osseotite surface is prepared by a process of thermal dual etching with hydrochloric and sulfuric acid, which results in a clean, highly detailed surface texture devoid of entrapped foreign material and impurities. This seems to enhance fibrin attachment to the implant surface during the clotting process. The authors retrieved 2 Osseotite implants after 6 months to repair damage to the inferior alveolar nerve. Histologically, both implants appeared to be surrounded by newly formed bone. No gaps or fibrous tissues were present at the interface. The mean bone-implant contact percentage was 61.3% (+/- 3.8%).

Acid Etching, Dental↗
PubMed2003

Bacterial adhesion on titanium nitride-coated and uncoated implants: an in vivo human study.

Titanium nitride (TiN) has been used in many fields as a surgical instrument coating that makes the surgical materials more resistant to wear and corrosion. The aim of the present study was an in vivo evaluation of the bacterial adhesion to TiN-coated (test) and uncoated (control) titanium implants. Six patients aged between 21 and 25 years and in excellent systemic health participated in the study. All of the participants gave their informed consent. The participants were selected on the basis of good periodontal health and no signs of mouth breathing. In each of the 6 participants, a removable acrylic device was adapted to the molar-premolar region of each quadrant of the jaws. One 4 x 13 mm titanium implant was glued to the buccal aspect of each device. The plasma spray covered 11.5 mm of the body of the implant, whereas the neck was machined titanium. Test implants were glued to the right devices and control implants were glued to the left devices. After 24 hours, the implants were removed from each device and processed for scanning electron microscopy for evaluation of the machined portion of the implant covered by bacteria. A total of 24 implants were used in this study, 12 test and 12 control. Surface characterization of the machined portion of the neck of the implant was performed on an additional 10 implants (5 test and 5 control). On test implants the implant surface covered by bacteria was significantly lower compared with that of control implants (P = .0001). The surface roughness was similar in both groups. TiN surfaces showed a significant reduction of the presence of bacteria, and this fact could probably be important in the decrease of the inflammation of the peri-implant soft tissues.

Adult↗
PubMed2003

Regeneration of the alveolar crest using titanium micromesh with autologous bone and a resorbable membrane.

Guided bone regeneration (GBR) has been used for the regeneration of bone in conjunction with the placement of oral implants. The aim of the present study was to clinically and histologically evaluate the use of a titanium micromesh and a resorbable membrane in the GBR technique in patients with alveolar crest defects due to periodontitis, trauma, and extractions. Eighteen patients participated in this study, and 50 implants were inserted. The postoperative healing was uneventful, no dehiscences were observed, and all implants were functioning successfully at 7-year follow-up. At reentry, in all cases, the space under the titanium mesh was completely filled by bone. From a clinical point of view, in all patients, no residual bone defects were observed and a significant increase of the alveolar width or height was found. In all cases, a good esthetic result of the restorative procedures was present.

Absorbable Implants↗
PubMed2003

Analysis of osteoblast-like MG63 cells' response to a rough implant surface by means of DNA microarray.

Several features of the implant surface, such as composition, topography, roughness, and energy, play a relevant role in implant integration with bone. Little is known about the structural and chemical surface properties that may influence biological responses. Expression profiling by DNA microarray is a molecular technology that allows the analysis of gene expression in a cell system. By using DNA microarrays containing 19200 genes, we identified several genes whose expression was significantly down-regulated in osteoblast-like cell line MG63 on a new implant surface (titanium pull spray superficial [TPSS] surface, Oralplant, Cordenons, PN, Italy). The differentially expressed genes cover a broad range of functional activities: (1) signaling transduction, (2) translation, (3) cell cycle regulation, (4) structural and metabolic functions, and (5) apoptosis. It was also possible to detect some genes whose functions are unknown. The data reported can be relevant to better understand the role of the type of surface on the molecular mechanism of implant osseointegration and as a model for comparing other materials.

Apoptosis↗
PubMed2003

Histologic evaluation of 2 human immediately loaded and 1 titanium implants inserted in the posterior mandible and submerged retrieved after 6 months.

Immediate loading can be successfully used in implant dentistry. Many factors are thought to be of importance in obtaining mineralized tissues at the interface. One such factor is the implant surface characteristics. The authors retrieved, after a 6-month loading period, 2 immediately loaded implants and 1 submerged implant, each of which had been inserted in posterior mandibles. Histology showed that, in both immediately loaded implants, mineralized tissue was present at the interface, and the bone-implant contact percentage was about 65% to 70%. No gaps, fibrous tissue, or inflammatory infiltrates were present at the interfaces. In the submerged (control) implant, the bone-implant contact percentage was much lower (about 35%). Our results showed that immediate loading of dental implants, even in the posterior regions of the jaw bones, hadn't caused untoward effects on the formation of mineralized tissues at the interface, producing, on the contrary, a higher bone-implant contact percentage than in the control implant, and thus, immediate loading can be a possible alternative procedure in implant dentistry.

Bone Marrow↗
PubMed2003

Immediate functional and non-functional loading of dental implants: a 2- to 60-month follow-up study of 646 titanium implants.

BACKGROUND: The aim of this study was the evaluation, from a clinical point of view, of implants subjected to immediate functional loading (IFL) and to immediate non-functional loading (INFL) in various anatomical configurations. METHODS: The study included 152 patients who had given their informed consent. A total of 646 implants were inserted. The implants were placed in 39 totally edentulous mandibles, 14 edentulous maxillae, 23 edentulous posterior mandibles, 16 edentulous anterior mandibles, 16 edentulous anterior maxillae, and 15 edentulous posterior maxillae. Fifty-eight implants were used to replace single missing teeth. In 65 cases, IFL was carried out for 422 implants. INFL was carried out in 116 cases, (224 implants). RESULTS: In the IFL group 6 of 422 implants failed (1.4%); in the INFL group 2 of 224 implants failed (0.9%). All the other implants appeared, from clinical and radiographic observations, to have successfully osseointegrated and have been functioning satisfactorily since insertion. All failures were observed in the first few months after implant loading. CONCLUSION: Immediate functional and non-functional loading seems to be a technique that gives satisfactory results in selected cases.

Adolescent↗
PubMed2003

Spreading of epithelial cells on machined and sandblasted titanium surfaces: an in vitro study.

BACKGROUND: The purpose of this investigation was to determine the influence of the surface structure of dental implants on epithelial cell spreading and growth in vitro. Cell morphology on machined and sandblasted titanium surfaces was investigated. METHODS: A total of 10 machined and 10 sandblasted discs and 10 glass coverslips were used for the present study. Samples were analyzed using scanning electron microscopy (SEM) and the cell spreading area was determined using a video image analysis system. RESULTS: After 24 hours incubation, keratinocytes grown on sandblasted titanium samples displayed numerous, long, and branched or dendritic filopodia closely adapted to the surface roughness. Filopodia varied from 3 to 12 microm in length and 0.1 to 0.3 microm in width. Cells cultured on a machined surface did not present such cytoplasmic extensions and displayed a round morphology. Keratinocytes seeded on glass coverslips were flat and edged by filopodia (maximum length 7 to 8 microm) on the spreading site of the cluster. Though cell morphology is comparable with that observed on sandblasted specimens, cytoplasmic extensions suggestive of strong adhesion and spreading attitude were less pronounced. CONCLUSION: These results indicate that sandblasted surfaces are the optimal substrata for epithelial cell adhesion and spreading.

Carcinoma, Squamous Cell↗
PubMed2003

Role of the microgap between implant and abutment: a retrospective histologic evaluation in monkeys.

BACKGROUND: It has been hypothesized that a certain width of the peri-implant mucosa is required to enable a proper epithelial-connective tissue attachment and, if this soft tissue dimension is not adequate, bone resorption will occur to ensure the establishment of attachment with an appropriate biological width. The reason for the accelerated bone loss around submerged 2-piece implants in the first year after the restoration is not known, but one possibility is that the gap between components plays a role in this process. Recent studies have shown that for all 2-part implants, the bone crest level changes appeared dependent on the location of the microgap. METHODS: The aim of the present study was a retrospective histologic evaluation in monkeys of the bone response to implants inserted 1 to 2 mm above the alveolar crest (group 1, 15 implants), at the level of the alveolar crest (group 2, 12 implants), or 1 to 1.5 mm below the alveolar crest (group 3, 13 implants). These implants had been early loaded, immediately loaded, and inserted immediately postextraction. RESULTS: In group 1, a 0.13 +/- 0.12 mm bone increase in a coronal direction was seen. In group 2, a 2.1 +/- 0.29 mm vertical bone loss was present. In group 3, a mean 3.6 +/- 0.46 mm vertical bone loss extending in an apical direction was observed. Statistically significant differences were observed between all 3 groups. CONCLUSIONS: Our results confirm data published previously that if the microgap was moved coronally away from the alveolar crest, less bone loss would occur and if the microgap was moved apical to the alveolar crest, greater amounts of bone resorption were present. This remodeling is not dependent on early and immediate loading of the implants or on immediate postextraction insertion.

Alveolar Bone Loss↗
PubMed2003

Clinical and histologic aspects of dental implants removed due to mobility.

BACKGROUND: Implant failures are rare but do occur. Mechanical factors are certainly important in implant failures; so are biologic, iatrogenic, and functional factors. Mobility is the cardinal sign of implant failure. Three major etiologic factors have been suggested for implant failures: infection, impaired healing, and overload. The aim of the present study was to histologically and histochemically evaluate the fibrous connective tissue found around failed dental implants removed due to mobility. METHODS: In a 5-year period, 51 root-form implants were retrieved because of mobility and underwent histological examination. Thin ground sections were obtained from each implant. RESULTS: Almost all implants had been inserted in posterior (premolar-molar) regions of both jaws. In all specimens, there was the presence of a 600 to 1,100 microm thick connective tissue between implants and surrounding bone. In every case, the surrounding bone was compact and highly mineralized, with well-structured Haversian canals and few areas of remodeling. No bacteria were found in the most coronal portion of the implants. A scarce inflammatory cell infiltrate was present in the connective tissue of some specimens. In about 10% of specimens, the epithelium tended to surround the perimeter of the implant. CONCLUSION: Our histological results are consistent with the hypothesis that late failures of osseointegrated implants can be caused by a combination of poor bone quality, mechanical trauma to bone, and overloading forces.

Alveolar Process↗
PubMed2003

Transforming growth factor-beta 1 expression in the peri-implant soft tissues of healthy and failing dental implants.

BACKGROUND: Transforming growth factor-beta (TGF-beta) is composed of a family of multifunctional polypeptide growth factors involved in embryogenesis, inflammation, regulation of immune response, angiogenesis, wound healing, and extracellular matrix formation. TGF-beta1 is the most common isoform found in human tissues. A role of TGF-beta in the pathogenesis of periodontal disease has been suggested. The aim of the present study was a comparative immunohistochemical evaluation of TGF-beta1 in normal keratinized gingiva and in the peri-implant soft tissues surrounding failing non-submerged implants. METHODS: Twenty patients participated in this study. Ten biopsies from healthy keratinized mucosa and 10 biopsies from peri-implant soft tissues surrounding failing implants were obtained (one biopsy per patient). The biopsies were obtained from different patients. RESULTS: In 5 cases of healthy mucosa, the stromal cells were positive between 1 to 5. In 7 cases, the epithelial layers were positive, between 1 and 18 cells. The superficial epithelial layer was negative in all cases. In 9 cases, there was a positivity of the vascular component, between 2 and 16 vessels. In failing implants, the stromal cells were positive in 6 cases, between 1 and 4. In all cases, cells of the epithelial layers were positive, between 15 and 40. The vascular component was positive in all cases, between 12 and 30 vessels. The differences between TGF-beta1 expression in the epithelium around healthy and failing implants were statistically significant (P < 0.0001). The differences between TGF-beta1 expression in the blood vessels in the soft tissues around healthy and failing implants were also statistically significant (P < 0.0001). No statistically significant difference was observed between the 2 groups in the TGF-beta1 expression in the stromal cells (P = 0.88). CONCLUSION: TGF-beta1 may be one of the most important factors in the regulation of the infiltrate, and in the production of tissue repair with a stimulation of fibroblasts and endothelial cells.

Adult↗
PubMed2002

Intraduct papilloma of the palate. Report of a case.

Salivary gland papillomas are rare tumours arising from ductal epithelium. Intraduct papillomas are the most rare of all duct papillomas. Only four intraduct papillomas have been described in a review of nearly 3100 epithelial salivary tumours. Intraduct papillomas are located almost exclusively in the excretory ducts of the minor salivary glands. However, also the major salivary glands may be affected. Microscopically, the tumour consists of fibrovascular papillae covered by a columnar or cuboidal epithelium. The authors describe an intraduct papilloma of the palate in a 74-year-old woman. The excision of the lesion was curative.

Aged↗
PubMed2002

Peripheral calcifying odontogenic cyst.

BACKGROUND: Calcifying odontogenic cyst (COC) is a rare lesion representing about 1% of jaw cysts. It may occur in a central (intraosseous) or peripheral (extraosseous) location. METHOD: A case of peripheral COC located on the gingiva, appearing as a painless, circumscribed, pink nodule has been reported. RESULTS: Peripheral, in contrast to central, COC tends to affect older patients. Peripheral COC is a less aggressive lesion than the central counterpart, and a simple excision biopsy is curative. CONCLUSION: The histological finding of a keratinized epithelium rich in ghost cells has helped in making the diagnosis.

Adult↗
PubMed2002

Primary gingival leiomyosarcoma. A clinicopathological study of 1 case with prolonged survival.

BACKGROUND: Leiomyosarcoma is a relatively uncommon mesenchymal tumor that exhibits smooth-muscle differentiation. Only 3 to 10% of leiomyosarcomas arise in the head and neck, the nose and paranasal sinuses, skin and subcutaneous tissue and cervical esophagus being the most common localizations. Most leiomyosarcomas involving the oral tissues primarily affect the maxillary sinus, the maxillary or mandibular bone. A review of the English-language literature since 1908 revealed 30 reported cases of primary leiomyosarcoma of the oral mucosa and soft tissues. MATERIAL AND METHODS: We report on a case of gingival leiomyosarcoma, arising in a 31-year-old female and involving the upper alveolar mucosa. Following the diagnosis of malignant neoplasm on frozen sections and an en-block resection, the tumour was formalin-fixed and paraffin embedded for histological and immunohistochemical examination. RESULTS: Microscopically, the tumor was composed of interlacing fascicles of spindle-shaped cells with elongated, blunt-ended nuclei and eosinophilic cytoplasm, containing PAS-positive granules. Mitoses, both typical and atypical, and scattered necrotic foci were present. Consistent desmin, muscle specific and alpha-smooth muscle-specific, and vimentin immunoreactivity was demonstrated in the tumor cells. The patient is alive and free of disease at a 7-year follow-up. CONCLUSIONS: Intra-oral leiomyosarcomas are exceptionally rare. Accurate diagnosis and treatment is largely based on the careful search of clinical signs indicative of malignancy (e.g., neoplastic bone destruction, wide invasion of adjacent tissues) and intra-operative (frozen sections) examination of the lesion. Though the case reported herein showed an attenuated clinical behavior, prolonged follow-up is mandatory in view of possible tumor relapse.

Actins↗
PubMed2002

Prevalence of p53, bcl-2, and Ki-67 immunoreactivity and of apoptosis in normal oral epithelium and in premalignant and malignant lesions of the oral cavity.

PURPOSE: Loss of normal p53 is correlated to the progression of several preneoplastic lesions to neoplasms, and overexpression of bcl-2 determines an alteration of programmed cell death. There is an increased awareness of the importance of apoptosis in cancerogenesis, and a strong correlation of Ki-67 with high tumor grade has been reported. MATERIALS AND METHODS: The aim of our study was to investigate immunohistochemically the expression and relationship of p53, bcl-2, MIB-1, and the apoptotic index (AI) in normal oral epithelium, leukoplakia, dysplasia, and oral squamous cell carcinoma. RESULTS: A strong correlation was found between p53 overexpression and cell proliferation (MIB-1) and the AI. An inverse relationship was found between bcl-2 expression and MIB-1 and AI. A significant inverse relationship was found between p53 and bcl-2. A good positive correlation was present between AI and MIB-1 expression. CONCLUSIONS: Apoptosis could be important to help to understand oral carcinogenesis.

Apoptosis↗
PubMed2002

Vascular endothelial growth factor (VEGF) expression in healthy and inflamed human dental pulps.

Vascular endothelial growth factor (VEGF) is a glycoprotein that has the capability to increase vascular proliferation and permeability. VEGF has been found to be expressed in several different types of tumors, and it may contribute to the progression of malignant tumors. Immunostaining for VEGF and factor VIII was performed in normal healthy pulps and in irreversible pulpitis. In both cases the vessels were always positive for VEGF. Our immunohistochemical data show that the expression of VEGF was strongly positive in the inflammatory infiltrate in irreversible pulpitis. VEGF expression in the stromal cells in healthy pulps ranged from 20 to 100% (with a mean of 68.82), and in irreversible pulpitis ranged from 0 to 100% (with a mean of 62.35%); this difference was statistically significant (p = 0.05). This down-regulation in the stromal cells in irreversible pulpitis could be due to the presence, in a low compliance system such as the dental pulp, of inflammatory infiltrate. VEGF is probably a factor implicated in the etiology and progression of pulpitis. The microvessel density in healthy pulps was 90.00 +/- 27.5, while, in irreversible pulpitis, it was 56.68 +/- 21.15. This difference was statistically significant (p = 0.001). The decrease in microvessel density in irreversible pulpitis could be related to failing vascular function and blood flow decrease.

Adolescent↗
PubMed2002

Ki-67 expression in dentigerous cysts, unicystic ameloblastomas, and ameloblastomas arising from dental cysts.

This study investigated whether or not an ameloblastoma developing in the wall of a dentigerous cyst is a distinct lesion from the unicystic ameloblastoma. An immunohistochemical evaluation of Ki-67 in dentigerous cysts, unicystic ameloblastomas, and ameloblastomas arising in dentigerous cysts was done. The values of Ki-67 positivity were 3.14 for the dentigerous cyst, between 5.32 and 16.56 for unicystic ameloblastoma, and 11.77 for ameloblastoma arising in a dentigerous cyst. Statistically significant differences were found between the dentigerous cyst and the unicystic ameloblastoma and between the dentigerous cyst and the ameloblastoma arising from a dentigerous cyst. No statistically significant difference was present between unicystic ameloblastoma and ameloblastoma arising from dentigerous cyst. These immunohistochemical data confirm the hypothesis that an ameloblastoma arising from a dentigerous cyst has a similar biological behavior to the unicystic ameloblastoma and should be considered as merely a histologic variant.

Adult↗
PubMed2002

CD1a-positive cells in odontogenic cysts.

Langerhans cells (LC) are bone marrow-derived cells that have a CD1a-positive immunophenotype and are an important portion of the cell-mediated immune response. The aim of this study was an immunohistochemical evaluation of CD1a positive cells in different types of oral cysts. Fifty-five cysts were studied: 18 odontogenic keratocysts (OKC), of which five were orthokeratotic and 13 parakeratotic; 19 radicular cysts; and 18 dentigerous cysts. Positive LC was 80% for orthokeratotic OKC, 33% for parakeratotic OKC, approximately 35% for radicular cysts, and approximately 20% for dentigerous cysts. The results show that OKC with well-differentiated epithelial linings presented a greater number of LC than the other cysts. However, when the cyst wall was inflamed there were no differences in LC expression in the different types of cysts. The data confirm that LC distribution seems to be associated with the degree of differentiation of the epithelia.

Adult↗