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Biomedical subjects

A Piattelli

Publications and source records attributed to A Piattelli.

At least 145 records · Page 8Linked to original sources
PubMed1995

Soft palate metastasis from a small cell carcinoma of the lung.

Metastases in the oral soft tissues are rare. They usually occur in the tongue and in the gingiva. The most common primary sites for lesions metastasizing to the oral tissues are lung, kidney, stomach, liver. The lung tumors are in the majority squamous cell carcinomas or adenocarcinoma; only rarely the primary tumors are small cell carcinomas. Small cell carcinoma is a highly malignant neoplasm with often extrathoracic metastases at the time of diagnosis, and a very low 5-years survival. Metastases from an occult lung carcinoma should always be considered in the differential diagnosis of small cell carcinomas in extrapulmonary sites.

Carcinoma, Small Cell↗
PubMed1995

Microbiological evidence of Helicobacter pylori from dental plaque in dyspeptic patients.

To evaluate the possible route of transmission of Helicobacter pylori, stomach biopsies and dental plaques were cultured from patients with dyspeptic symptoms who underwent endoscopy. A total of 31 patients were examined. Twenty patients out of thirty one (64%) were H. pylori positive in gastric biopsy. Among the microorganisms isolated in dental plaque only one sample (corresponding to a patients with duodenal ulcer H. pylori positive) showed colonies morphologically and biochemically compatible with H. pylori. Proteic patterns of whole cells and restriction endonuclease analysis with Hind III and Hae III endonucleases of DNA extracted from the strain subcultured from a stomach biopsy and from dental plaque of the same patient indicated that both sites were infected with the same strain of H. pylori.

Adult↗
PubMed1995

Multiple impacted and erupted supernumerary premolars.

The authors present a case of a 22-years-old patient with five supernumerary impacted and erupted premolars in the mandible. This dental anomaly is relatively rare occurring from 0.14% to 0.64% of the general population. About 75% of supernumerary premolars seen to be erupted.

Adult↗
PubMed1995

Lymphoepithelial cyst of the parotid gland.

Cystic lesions of the parotid gland are not common and are often erroneously diagnosed as benign tumors. Lymphoepithelial cysts are only rarely diagnosed in the parotid gland. The term "lymphoepithelial cyst" is used because it is a descriptive term and takes no account of the origin and development of these cysts. An origin from sequestered lymph nodes epithelium in the parotid gland may be a feasible explanation for the origin of these cysts.

Cysts↗
PubMed1994

A light and laser scanning microscopy study of bone/hydroxyapatite-coated titanium implants interface: histochemical evidence of unmineralized material in humans.

The authors describe a light and laser scanning microscopy study of hydroxyapatite-coated titanium implants retrieved from humans. A histochemical technique, using von Kossa and basic fuchsin, allowed clear differentiation between mineralized bone and unmineralized bone matrix. The bone-hydroxyapatite (HA) interface presented variable features: in some areas the mineralized bone was directly apposed to the HA surface, while in others an unmineralized red-stained material, probably osteoid, was interposed. Laser scanning microscopy confirmed these findings showing a thin layer of fluorescent material at the interface.

Bone and Bones↗
PubMed1994

Histochemical and confocal laser scanning microscopy study of the bone-titanium interface: an experimental study in rabbits.

The aim of our study was an analysis of the presence of an unmineralized bone matrix between mineralized bone and titanium screws in rabbit tibiae. A microscopical analysis, using a histochemical technique, was performed on the titanium-bone interface of commercially pure titanium implants placed in rabbit tibiae and harvested after 2 months. Thin ground sections of the specimens were prepared by the cutting-grinding system and stained using the von Kossa method for calcium salts and basic fuchsin for osteoid. The microscopical and morphometrical evaluation showed that bone covered about 40% (+/- 7.5%) of all implants. Mineralized bone was, however, in direct contact with the titanium surface on only about 10% of the implant, while in the remaining 30% the mineralized bone was separated from the implant by an unmineralized tissue. This basophilic, probably osteoid matrix, could represent the medium that allows the biochemical exchanges between bone and cells under the influence of the implant. A small, optically translucent gap (1-5 microns), probably an artifact, was present in some areas between titanium and bone. Confocal laser scanning microscopy (CLSM) in a fluorescent mode showed the presence at the interface of a fluorescent material. Results from our study showed that light microscopy of thin ground sections allowed a good analysis of the real nature of the titanium-bone interface. Moreover, this double staining technique showed the presence of an unmineralized bone matrix at most of the bone-titanium interface.

Animals↗
PubMed1994

Clear cell odontogenic carcinoma. Report of a case with lymph node and pulmonary metastases.

The authors present a case of a rare type of odontogenic tumour, recently described as "clear cell odontogenic tumour". The patient died 5 years after the initial diagnosis with lymph node and diffuse pulmonary metastases. This fact can support the view that this tumour, histologically characterised by the presence of cells with a clear cytoplasm, can behave in an aggressive way and has true metastatic potential, despite the absence of malignant cellular features.

Adenocarcinoma, Clear Cell↗
PubMed1994

Freeze-dried dura mater for guided tissue regeneration in post-extraction dental implants: a clinical and histologic study.

Soft membranes were used in 69 patients for bone regeneration around implants (blades and screws, submerged and non-submerged) placed into extraction sockets. In about 10% of the patients a prosthetic restoration was completed immediately, while in the remaining patients the prostheses were connected after a healing period of 3 to 6 months; follow-up ranged from 6 to 30 months. In 22 patients a re-entry procedure was done to evaluate the membrane and in 4 patients a bone biopsy was taken from 3 to 6 months after the placement of the membrane. In all cases the peri-implant tissues appeared clinically healthy and it was possible to see radiographically that the newly formed bone closely adapted to the implants. In most cases it was possible at 6 months re-entry to see the membrane and detach it from the underlying tissues. There was a partial dehiscence of the membrane in only 4% of the cases. After 3 months the tissue under the membrane presented macroscopical features similar to mature bone, and bone biopsies in all cases showed a spongious lamellar bone with a high level of activity and a wide band of osteoid tissue.

Adult↗
PubMed1994

A preliminary report on a method for studying the permeability of expanded polytetrafluoroethylene membrane to bacteria in vitro: a scanning electron microscopic and histological study.

The technique of guided tissue regeneration using expanded polytetrafluoroethylene (ePTFE) membranes has been shown to be effective in implant dentistry (bony defects, extremely thin alveolar ridges, and implants placed in fresh extraction sockets). One of the drawbacks associated with the use of membranes is their premature exposure with consequent bacterial contamination. The aim of this study was to examine the possibility that oral bacteria migrate through the occlusive portion of ePTFE membranes and to determine the time needed for microorganisms to pass from the outer surface to the inner surface of the membranes. A removable acrylic device was adapted to the molar-premolar region of one quadrant of the jaws in each of three volunteers. Five cylindrical teflon chambers were glued to the buccal aspect of each device. The chambers were divided into two rooms separated by the inner portion of a ePTFE membrane. The outer room was open to the oral cavity allowing plaque accumulation; the inner room was isolated from the oral cavity by the ePTFE membrane. One of the 5 chambers was completely closed and used as control. The test period lasted for 4 weeks. Every week, one chamber was removed from each device and processed for scanning electron microscopic and histologic examinations. Our study showed the possibility that oral bacteria may contaminate ePTFE membranes exposed to the oral cavity. One specimen showed partial bacterial penetration after 2 and 3 weeks, but after 4 weeks, all membrane specimens demonstrated bacterial contamination.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Composite resin-amalgam compound restorations.

Extensive silver amalgam restorations in premolars and molars occasionally require sacrifice of healthy unsupported enamel walls or cusps. A posterior composite resin-amalgam compound technique has been proposed to conserve these structures. Microleakage was high at the enamel-amalgam interface, moderate at the composite resin-silver amalgam and dentin-composite resin interfaces, and minimal between the inner enamel and the composite resin. Light microscopy and scanning electron microscopy demonstrated that marginal adaptation of the silver amalgam to the composite resin of the cusps was acceptable and that penetration of the inner etched enamel to the composite resin was complete.

Bicuspid↗
PubMed1994

Vertical ridge augmentation using a membrane technique associated with osseointegrated implants.

The purpose of this study was to evaluate: (1) the surgical protocol, effectiveness, and reliability for vertical ridge augmentation using a new titanium-reinforced membrane and osseointegrated implants; and (2) the histologic characteristics of the interface between a pure titanium implant and newly regenerated human bone. Five patients received 15 conical Brånemark-type implants in six different surgical sites requiring vertical augmentation. The implants protruded 4 to 7 mm from the bone crest. Pure titanium miniscrews (1.3 x 10 mm) were positioned distally to the implants, protruding 3 to 4 mm from the bone level. The implants and the miniscrews were covered with a titanium-reinforced membrane, and the flaps were sutured. Membranes were removed at the stage 2 surgery after 9 months of healing. Measurements of biopsy specimens showed a gain in bone height from 3 to 4 mm. Histologic examination showed that all retrieved miniscrews were in direct contact with bone. Histomorphometric analysis of bone contact gave a mean value of 42.5 +/- 3.6% for five of the six examined miniscrews. The results suggest that the placement of implants protruding 3 to 4 mm from the top of resorbed bone surfaces may result in vertical bone regeneration to the top of the implant cylinder and that the regenerated bone is able to osseointegrate pure titanium implants.

Adult↗
PubMed1994

Qualitative and quantitative comparative study on different filling materials used in bone tissue regeneration: a controlled clinical study.

This study compared, in a human model, the ability of (1) expanded polytetrafluorethylene (e-PTFE) membranes plus bone-chip autografts, (2) e-PTFE membranes plus demineralized freeze-dried bone, (3) e-PTFE membranes plus a new form of demineralized allograft bone tissue, and (4) e-PTFE membranes alone to enhance bone regeneration around dental implants placed into recent extraction sockets. The histologic results demonstrated that, in humans, guided tissue regeneration techniques are capable of producing new bone osseointegrated with titanium dental implants. Among the graft materials, autogenous bone provided the densest and the greatest amount of bone formation, but use of demineralized freeze-dried bone and a new form of de-mineralized allogenic bone matrix also improved bone regeneration compared to membranes alone after 6 months of healing.

Alveolar Bone Loss↗
PubMed1993

Bone ingrowth into hydroxyapatite coating: a light microscopy and laser scanning microscopy study.

The authors present a description of the presence of organic material inside the hydroxyapatite (HA) coating of Calcitek implants inserted in rabbit tibia. Light microscopy showed that in all specimens a granular basophilic material which was not mineralized was present inside the thickness of the coatings. In two specimens out of 40, a bone-like substance was observed in some areas of the coating, at a distance from the interface. Laser scanning microscopy showed in all specimens an autofluorescence of osteocytes, osteoblasts, of the interface, and inside the coating. The presence of bone could either show an ability of the coating to serve as a scaffold for the newly forming osseous tissue or be a sign of an initial degradation of the HA.

Animals↗
PubMed1993

Pulp obliteration: a histological study.

Pulp obliteration is a very rare occurrence that is most frequently caused by trauma. A 58-yr-old female patient had a generalized pulp obliteration that involved all maxillary and mandibular teeth. One tooth was extracted due to an extensive carious lesion and it was processed by a cutting-grinding technique. It was possible to observe the complete obliteration of the pulp chamber, which was filled in part by reparative dentin and in part by a calcified tissue with a concentric layers structure with no tubular pattern. The root canals were almost completely obliterated by an amorphous calcified material.

Dental Pulp Calcification↗
PubMed1993

A light microscopy, scanning electron microscopy, and laser scanning microscopy analysis of retrieved blade implants after 7 to 20 years of clinical function. A report of 3 cases.

The aim of the present study was to evaluate by means of light microscopy, scanning electron microscopy, and laser scanning microscopy the thin ground sections of blade implants retrieved after 7 to 20 years of clinical function. Microscopic examination revealed that most of the implant surface had an intimate contact with compact lamellar bone tissue. Higher magnifications revealed the presence of a gap (1 to 5 mu) interposed between bone and implant. Many osteocytes were near the implant surface and, in many instances, osteocyte canaliculi, running from the lacunae towards the implant surface, were seen. Structures similar to bone reversal lines were observed at the edge of the bone side of the interface. The bone-titanium region is probably an area of dynamic biological activity.

Aged↗
PubMed1993

Microscopic and chemical analysis of bone-hydroxyapatite interface in a human retrieved implant. A case report.

The aim of the present study was a histological and chemical analysis of the bone-hydroxyapatite interface in a retrieved human implant. The implant was cut in two: one half was processed for light microscopy with the cutting grinding system, and the other for SEM analysis with EDX and a cathodoluminescence system. Bone maintained an intimate contact with the hydroxyapatite and the bonding of the hydroxyapatite with the metal was very strong. An analysis of the interface from a double staining (basic fuchsin and von Kossa) showed a non-mineralized matrix, interposed between hydroxyapatite and bone in many areas. It is possible that different microscopic features are present in different areas of the interface, however, intimate contact was observed 6 months after insertion of the implant.

Calcium↗
PubMed1993

Histologic analysis of a screw implant retrieved from man: influence of early loading and primary stability.

This paper presents a histologic analysis of a one-piece screw implant put into immediate function and retrieved from man after 7 years of clinical function. Compact lamellar bone with many Haversian canals and osteons was found very near the metal surface, and the morphometric analysis of the perimeter of the implant showed a percentage of bone contact of 86.69% (SD = 5.43). The compact bone was particularly thickened around the top of the spires. At high-power magnification, it was possible to observe optically a small empty gap between bone and titanium, and the use of a histochemical stain (von Kossa) showed that mineralized bone was separated from the metal surface by a very thin layer of unmineralized red-stained material; this layer had the same staining features as the osteoid and the osteocyte lamina limitans.

Aged↗