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Biomedical subjects

A Piattelli

Publications and source records attributed to A Piattelli.

At least 127 records · Page 7Linked to original sources
PubMed1996

Non-Hodgkin's lymphoma of the tongue: a case report.

Oral manifestations are present in about 3-5% of cases of non-Hodgkin's lymphoma (NHL) and oral lesions are only rarely the initial manifestations of NHL. A case is presented of an 80-year-old patient with a NHL of the tongue, without visceral or lymph node involvement. The diagnosis of NHL can be made only by biopsy. The prognosis of NHL seems to be related to the tumour stage, tumour aggressiveness and response to treatment: the oral lesions appear to respond quite well to irradiation.

Aged↗
PubMed1996

Complex odontoma as a periapical and interradicular radiopacity in a primary molar.

Only rarely is a mature complex odontoma seen in a periapical location and in association with a primary tooth. Complex odontomas usually present as a radiopacity with a radiolucent rim. The differential diagnosis must include mature fibro-osseous lesions (e.g. cementoblastoma). Complex odontomas can be differentiated from fibro-osseous lesions because they usually present a nonhomogeneous radiopacity and almost always will present as solitary lesions. For complex odontomas located in the periapical region, the differential diagnosis must include idiopathic periapical osteosclerosis. In this case, the presence of the radiolucent rim and the presence of denser, sharper radiopacities produced by enamel distinguish the odontoma.

Adult↗
PubMed1996

Histological evaluation of freeze-dried dura mater (FDDMA) used in guided bone regeneration (GBR): a time course study in man.

In 26 patients freeze-dried dura mater (FDDMA) membranes were used in fenestrations and dehiscences around dental implants, in implants inserted into postextraction sockets, in vertical ridge augmentation and in sinus lifting procedures. A re-entry procedure was carried out after 6, 9 and 12 months. In all patients a small portion of the membrane was removed and examined. No inflammatory infiltrate was present in the tissues around the membranes. No cells were present inside the membranes and only in the most peripheral portions was it possible to observe a few cells positive to acid phosphatase. The FDDMA membranes appeared to resorb slowly, did not seem to elicit an inflammatory reaction, and at 12 months they still appeared to play a role in cell occlusion.

Adult↗
PubMed1996

Bone tissue reactions to demineralized freeze-dried bone in conjunction with e-PTFE barrier membranes in man.

Demineralized freeze-dried bone (DFDB) has been demonstrated to be osteoinductive in rodents, while no new bone formation has been reported at ectopic sites in goats, dogs and monkeys. In the present study, DFDB was used in connection with dental implant placement and expanded polytetrafluorethylene (e-PTFE) membranes. Histological examination showed that DFDB particles near the host bone underwent a partial remineralization, while DFDB distant from pre-existing bone was slowly resorbed and showed no remineralization, no osteoinduction, and no osteoconduction. This could be due either to the fact that the response to osteoinductive stimuli is lower in higher species, or to the fact that large quantities of DFDB are required to provide sufficient quantities of bone morphogenetic protein.

Alveolar Bone Loss↗
PubMed1996

Vertical ridge augmentation using a resorbable membrane: a case report.

The vertical dimension may be very important clinically where anatomic structures may limit the bone height available for implant insertion. Moreover, lack of bone tissue may result in exposure of implant threads, soft tissue recession, less-than-optimal implant stability, and esthetic problems in the prosthetic reconstruction. Attempts have been made to increase the bone height with the placement of autografts and allografts on top of the ridge, but long-term results have been unsatisfactory. Recently an increase of bone in a vertical direction has been obtained in rats, rabbits, and man using expanded polytetrafluoroethylene (ePTFE) membranes. The authors present a case in which an increase of the vertical dimension of the alveolar ridge was obtained using a resorbable freeze-dried dura mater membrane in association with demineralized freeze-dried bone. After a 6-month uneventful healing period the space under the membrane was filled by a tissue with the macroscopic features of bone, and the two implants were almost covered by the newly-formed tissue. An histological examination of a retrieved sample of the newly formed tissue demonstrated the presence of mature bone. It can be concluded that a localized vertical increase of the alveolar ridge may be obtained with the use of a resorbable freeze-dried dura mater membrane.

Adult↗
PubMed1996

Juvenile hyaline fibromatosis of gingiva: a case report.

Juvenile hyaline fibromatosis is an extremely rare inherited condition, probably resulting from an inborn error of metabolism. It is characterized by cutaneous nodules, gingival hypertrophy and joint contractions. It affects children but usually it is not present at birth, and is microscopically characterized by a conspicuous hyalinization of the connective tissue.

Child↗
PubMed1996

Cellular colonization and bone formation into expanded polytetrafluoroethylene membranes: a light microscopical and histochemical time course study in the rabbit.

We report on a time course study of cellular colonization of expanded polytetrafluoroethylene (ePTFE) membranes in rabbits. Bone defects (8 mm) were prepared with low speed burs in rabbit tibial metaphyses and covered with ePTFE membranes. The membranes were retrieved after 3, 6, 9, and 12 weeks. At 3 weeks, all membranes were filled by cells and osteoid tissue: no mineralized tissue was found. Osteoblasts positive for alkaline phosphatase (ALP) were observed on the outer surface and inside the material interstices of the membrane. At 6 weeks, it was possible to observe an increase of the quantity of the osteoid material inside the membranes. At 9 weeks, bone tissue was present and it usually originated from the most external part of the membrane, and spread to the central part of the membrane. Only the central portion of this bone appeared to be completely mineralized. A sharp decrease in the number of ALP-positive osteoblasts was observed. At 12 weeks, the quantity of bone present appeared to be substantially increased. Only a small percentage of the bone inside the membrane appeared to be completely mineralized. No cells positive to acid phosphatase were observed. These histological results confirm the high biocompatibility of ePTFE membranes and the bone formation inside the ePTFE interconnected nodes could, probably, help in achieving a good biomaterial-tissue integration with predictable results in bone regeneration.

Alkaline Phosphatase↗
PubMed1996

Microscopical observations of the osseous responses in early loaded human titanium implants: a report of two cases.

The authors present the histological picture of the surrounding tissues of two screw-shaped titanium plasma-sprayed implants retrieved for a fracture of the abutment after 18 and 42 months, respectively. These two implants were loaded after two months. The microscopical examination showed that both implants were covered in a large part of the implant surface by compact, mature lamellar bone with the presence of many Haversian systems and osteons. With von Kossa staining it was possible to see that the bone at the interface with the implant was highly mineralised. No connective tissue or inflammatory cells were present at the interface.

Adolescent↗
PubMed1996

A histologic study of nonsubmerged titanium plasma-sprayed screw implants retrieved from a patient: a case report.

The authors report on the microscopic findings in two plasma-sprayed nonsubmerged implants retrieved from a patient 6 months after placement. One of the implants had been loaded for 3 months, while the other was left unloaded. Clinically, the peri-implant gingival tissues were in good health. The implants were sectioned according to the cutting-grinding system. Bone lined the titanium surface almost completely with 77.3% +/- 5.1% of contact in the unloaded implant and 86.5% +/- 3.3% of contact in the loaded implant. Signs of bone resorption with many macrophages and osteoclasts were present in the loaded implant, while in the unloaded implant only osteoclast resorption activity was demonstrable.

Alveolar Bone Loss↗
PubMed1996

GBR with an e-PTFE membrane associated with DFDBA: histologic and histochemical analysis in a human implant retrieved after 4 years of loading.

As a result of a fracture to the cemented post and core, a pure titanium implant was extracted from a 54-year-old patient after 4 years of clinical loading. At implantation, the implant was positioned into an extraction socket and the defect was treated with an e-PTFE membrane associated with a DFDBA graft. At retrieval the implant underwent histologic and histochemical examination to assess the characteristics of the regenerated bone after 4 years of prosthetic loading. The implant showed an angular bony defect at the smooth collar, but the bone-implant direct contact rate seemed to be elevated in the remaining implant surface. Normal transmitted and polarized light examinations demonstrated that most of the DFDBA particles were resorbed and substituted by vital newly formed bone. The regenerated bone appeared compact with secondary osteons and large haversian canals; however, some partially mineralized remnants residuated in the spaces, between the osteons. Within the limits of this study, the authors concluded that DFDBA can be substituted by the host bone, but the rate of substitution is very slow and not complete after 4 years. From a clinical point of view, however, the load-bearing capacity of the bone regenerated with the membrane technique associated with DFDBA appeared to be similar to that of normal bone.

Alveolar Bone Loss↗
PubMed1995

Detection of alkaline and acid phosphatases around titanium implants: a light microscopical and histochemical study in rabbits.

Alkaline phosphatase (ALP) may play a very important role in the mineralization process of bone, while acid phosphatase (ACP) is implicated in bone resorption. The aim of the present study was a histochemical characterization of ALP and ACP at the bone-implant interface after the insertion of smooth screw-shaped threaded titanium implants in rabbit tibia. In the first 3 weeks it was possible to observe a very strong positivity in the cytoplasm of osteoblasts near the implant surface. These osteoblasts surrounded islands of soft tissue or trabeculated woven bone. In the first 4 weeks a large quantity of newly formed bone originating from the periosteal and endosteal surfaces was observed; a remodeling of the cortical bone was also present. A sharp decrease of the ALP activity was observed from the third week onwards, and at 2 months it was possible to observe that the ALP and ACP activities were similar, possibly in relation to the remodelling of bone. From 2 to 6 months there were no morphological differences in the microscopical appearance of the bone around the implants. The bone was mature, compact and the new bone had staining features similar to pre-existing bone.

Acid Phosphatase↗
PubMed1995

Localized chronic suppurative bone infection as a sequel of peri-implantitis in a hydroxyapatite-coated dental implant.

Plaque-induced lesions can produce peri-implant bone loss with ultimate implant loss. Although the peri-implant tissues seem to be more resistant than the periodontal ones to plaque and calculus, they can produce a more extensive spread of the infection to the deeper tissues around implants. The case of a 45-year-old female patient is presented in which, over a three year period, there was a progressive loss of peri-implant bone and the formation of a periapical radiolucency with an external fistula. The implant was removed and examined with the cutting-grinding system. Microscopy examination showed that most of the hydroxyapatite (HA) was still adherent to the metal. There was a detachment in the area of the HA-titanium interface. The implant surface was almost completely covered by bacteria. Bacteria were also present in the bone medullary spaces surrounding the implant. The infection of the periodontal tissues had progressed into the alveolar bone, thus producing a localized bone infection. The cause of the implant failure is probably related to a defective connection of the abutment or to overloading of the implant due to the presence of interlocks in the prosthetic restoration.

Bone Resorption↗
PubMed1995

Head and neck non-Hodgkin's lymphomas.

74 patients with non-Hodgkin's lymphoma (NHL) in the head and neck were studied and 21 out of 74 (28.4%) had a primary extranodal location. The most commonly affected lymph nodes were the lateral cervical (48%); the extranodal NHL occurred most frequently in Waldeyer's ring (19%) and orbit (5.4%). Overall 10-year survival was 55.2% with a median survival of 42 months, and survival was higher in extranodal (67.3%) than in nodal locations (51.9%). No statistically significant difference between the survival of high-grade and low-grade tumours was observed. There was, on the contrary, a correlation between stage of the disease and survival of the patients. Most cases were B-cell lymphomas (91.8%). Nodal NHL presented at diagnosis in an advanced stage in a higher percentage (71.2%) than extranodal (48%). High-grade tumours seemed to affect mainly young people.

Adolescent↗
PubMed1995

Bacterial penetration in vitro through GTAM membrane with and without topical chlorhexidine application. A light and scanning electron microscopic study.

Premature exposure of membrane in the oral cavity is considered the most common complication as well as a reason for failure or incomplete success of guided tissue regeneration, as the exposed membrane undergoes plaque accumulation. A method to control, or at least to reduce the bacterial invasion of the membrane allowing a delay in the membrane removal, could be of clinical interest. The purpose of the present study was to evaluate the possibility of treating, with topical chlorhexidine application, the bacterial colonization of exposed membranes. A special device was developed in order to evaluate, under an experimental environment, the bacterial colonization. This device was made from a removable acrylic denture base to which 5 gold cups were attached. The cups consisted of an internal compartment, isolated from the oral cavity by a GTAM membrane, and an external compartment exposed to the oral environment. 3 healthy subjects had this device fitted, bilaterally, in the molar-premolar region of the upper jaw. The cups of one side of each subject had 0.2% chlorhexidine gluconate gel applied 2x a day for 1 min, whereas those of the other side served as controls. 12 cups were removed after 2 weeks and the remainder removed after 1 month. The non-treated control specimens were characterized by greater amounts of plaque accumulation. In all the test sites, plaque deposits increased in thickness and quantity during the 4 weeks of the experiment. Complete invasion of the membrane and initial colonization of its internal surface were observed only in 4-week specimens. A relatively simple flora consisting mainly of cocci and short rods, was found in bacterial deposits forming under the influence of chlorhexidine, whereas in non-treated specimens, it was possible to observe a more mature and complex plaque, composed mostly of filamentous bacteria. In conclusion, topical application of chlorhexidine gel is an effective method of reducing plaque and calculus formation on the surface of GTAM membranes exposed to the oral cavity for up to 4 weeks. This study has, however, failed to demonstrate the capacity of chlorhexidine to prevent or to retard bacterial penetration through the thickness of the inner portion of the membranes.

Acrylic Resins↗
PubMed1995

Abscess formation around the apex of a maxillary root form implant: clinical and microscopical aspects. A case report.

This case report describes the occurrence of an abscess in the periapical area of a root form maxillary titanium implant, with a radiolucent appearance and purulent discharge. The removal of the infected periapical tissues was carried out but the clinical symptoms of infection persisted, an attempt at guided tissue regeneration with a freeze-dried dura mater membrane notwithstanding, and it was necessary to remove the implant. The microscopical examination showed that it was possible to observe nonviable bone tissue, with absence of bone cells and areas of bone resorption in the apical portion of the implant. These microscopical features were compatible with an acute localized suppurative osteomyelitis.

Adult↗
PubMed1995

Eosinophilic granuloma of the mandible involving the periodontal tissues. A case report.

This case reports on a 14-year-old boy with multiple radiolucent lesions widely distributed in the mandible, particularly in the right side (body-angle-ascending ramus). The lesion was first diagnosed as early-onset periodontitis and treated accordingly. It continued to grow very quickly, however, over a 6-month period, resulting in involvement of the entire mandible, with complete destruction of the lingual cortical bone, erosion of the external cortex with expansion in the neighboring soft tissues, and with a periosteal reaction in some areas. This case may serve to illustrate the rapid progress of eosinophilic granuloma, the importance and the difficulties of an early diagnosis, and the consequences of late diagnosis and treatment.

Adolescent↗
PubMed1995

Osteoma of the mandible. A case report.

The authors present a case of osteoma of the mandible. Osteomas are solitary lesions occurring predominantly in the skull and many authors believe that most osteomas in the maxillofacial areas are reactive bone hyperplasia or advanced ossifications. In some countries the prevalence of the osteoma is about 1% of all patients in the ENT clinics. Malignant transformation has not been described and surgery of the lesion should be conservative and consist essentially of enucleation.

Adult↗