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Biomedical subjects

M Piattelli

Publications and source records attributed to M Piattelli.

89 records · Page 5Linked to original sources
PubMedDate not supplied

A histologic evaluation of eight cases of failed dental implants: is bone overheating the most probable cause?

Biomechanical overloading has been stated to be, overall, the major cause of implant failures. Very important can be, however, in the etiopathogenesis of early implant failure, the overheating of the surgical site. The authors present eight cases of implant loss most probably due to bone overheating, even if other causes cannot be excluded. The microscopical picture, in all cases, was composed by the same features: (1) presence of bone sequestra; (2) no regeneration of the peri-implant bone; (3) presence of an inflammatory infiltrate in the gap between bone and implant; (4) no organization of the peri-implant bone clot; (5) presence of a compact and mature bone around the implant; (6) presence of bacteria around the implant and the necrotic bone.

Biomechanical Phenomena↗
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Antimicrobial tetraprenylphenols from Suillus granulatus.

From fruit bodies of the basidiomycete Suillus granulatus the tetraprenylphenols 2-6 were isolated. Their structures were elucidated by means of chemical and spectroscopic methods. Compounds 4 and 5 possess antimicrobial properties.

Anti-Bacterial Agents↗
PubMedDate not supplied

Bone-hydroxyapatite interface in retrieved hydroxyapatite-coated titanium implants: a clinical and histologic report.

Two hydroxyapatite-coated implants were retrieved after 12 months of loading because of a fracture of the abutments. The specimens were treated to obtain thin ground sections, and a microprobe chemical analysis was done under a scanning electron microscope equipped with an energy-dispersive x-ray analysis and cathodoluminescence system. Under light microscopy, close contact between the bone and the hydroxyapatite coating was seen, with no gaps at the interface. In some areas of the coating a reduction of the coating thickness could be observed, along with the presence of some detached hydroxyapatite particles embedded in newly formed bone. The chemical analysis of the cathodoluminescent areas at the interface showed a reduced calcium:phosphorus ratio in this region.

Calcium↗
PubMedDate not supplied

Bone reactions to anorganic bovine bone (Bio-Oss) used in sinus augmentation procedures: a histologic long-term report of 20 cases in humans.

Many materials are used for sinus augmentation procedures. Anorganic bovine bone (Bio-Oss) has been reported to be osteoconductive, and no inflammatory responses have been observed with the use of this biomaterial. One of the main questions pertaining to Bio-Oss concerns its biodegradation and substitution by host bone. Some investigators have observed rapid replacement by host bone, while other researchers observed slow resorptive activity or no resorption at all. The aim of the present study was to conduct a long-term histologic analysis of retrieved specimens in humans where Bio-Oss was used in sinus augmentation procedures. Specimens were retrieved from 20 patients after varying periods from 6 months to 4 years and were processed to obtain thin ground sections. Bio-Oss particles were surrounded for the most part by mature, compact bone. In some Haversian canals it was possible to observe small capillaries, mesenchymal cells, and osteoblasts in conjunction with new bone. No gaps were present at the interface between the Bio-Oss particles and newly formed bone. In specimens retrieved after 18 months and 4 years, it was also possible to observe the presence of osteoclasts in the process of resorbing the Bio-Oss particles and neighboring newly formed bone. Bio-Oss appears to be highly biocompatible and osteoconductive, is slowly resorbed in humans, and can be used with success as a bone substitute in maxillary sinus augmentation procedures.

Absorbable Implants↗
PubMedDate not supplied

Surface analysis of machined versus sandblasted and acid-etched titanium implants.

Initially, implant surface analyses were performed on 10 machined implants and on 10 sandblasted and acid-etched implants. Subsequently, sandblasted and acid-etched implant cytotoxicity (using L929 mouse fibroblasts), morphologic differences between cells (osteoblast-like cells MG63) adhering to the machined implant surfaces, and cell anchorage to sandblasted and acid-etched implant surfaces were evaluated. Results indicated that acid etching with 1% hydrofluoric acid/30% nitric acid after sandblasting eliminated residual alumina particles. The average roughness (Ra) of sandblasted and acid-etched surfaces was about 2.15 microns. Cytotoxicity tests showed that sandblasted and acid-etched implants had non-cytotoxic cellular effects and appeared to be biocompatible. Scanning electron microscopic examination showed that the surface roughness produced by sandblasting and acid etching could affect cell adhesion mechanisms. Osteoblast-like cells adhering to the machined implants presented a very flat configuration, while the same cells adhering to the sandblasted and acid-etched surfaces showed an irregular morphology and many pseudopodi. These morphologic irregularities could improve initial cell anchorage, providing better osseointegration for sandblasted and acid-etched implants.

Acid Etching, Dental↗
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[A histological study of hard dental tissues in nondecalcified sections using the cutting-grinding technic].

With the cutting-grinding technique (Exakt System) it is possible to obtain sections with a width of less than 10 microns of specimens such as teeth, crowns, bridges, implants, mineralized structures, which cannot be cut with routine histological techniques. In the present paper the authors study the efficacy of this technique in hard dental tissues.

Dental Cementum↗
PubMedDate not supplied

[Apicoectomy].

Explore the source record for details and available documents.

Apicoectomy↗
PubMedDate not supplied

Calcifying odontogenic cyst associated with compound odontoma: a study on undemineralized material.

In a minority of cases of calcifying odontogenic cyst (COC) it is possible to observe the formation of dental hard tissues in the cyst wall. The use of undemineralized sections has allowed an evaluation of the mineralized tissues normally lost with the use of demineralizing agents. All the dental hard tissues presented a high degree of morpho- and histodifferentiation. The histochemical staining for calcium salts (von Kossa) showed the presence of areas of low mineralization in the portion of the lesion, where the tissue maturation was not complete. In conclusion the appearance of the dental hard tissues in this case of compound odontoma arising in the cyst wall of a COC is similar to that already described in compound odontoma not associated with COC.

Adult↗
PubMedDate not supplied

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

An experimental study was done in rabbits to characterize the bone-hydroxyapatite (HA) interface by the use of histochemical staining for mineralized tissue and laser scanning microscopy (LSM) on undemineralized sections. Twenty HA-coated Sustain implants were placed in rabbit femurs and retrieved after 6 months. The specimens were then processed to obtain thin ground sections. In all specimens, there was intimate contact between bone and HA. In some portions, mineralized bone was in tight, direct contact with the HA, while in other portions, a basophilic unmineralized material was present between bone and HA. This material was thicker in areas with active bone formation upon the HA surface and had staining characteristics similar to the material present around the osteocyte lacunae. LSM showed a fluorescence present in many areas of the interface, in osteocyte lacunae, and inside the coating. An organic bonding between bone and HA can probably be hypothesized.

Animals↗
PubMedDate not supplied

Light and scanning electron microscopic report of four fractured implants.

Although they are fortunately rare, implant fractures can cause significant problems for both clinicians and patients. The authors present a light and scanning electron microscopic study of four fractured implants in two patients. Both patients had parafunctional habits (bruxism), hypertrophic masticatory muscles, and wear of occlusal surfaces. The scanning electron microscopic study of the fractured surfaces of all four implants showed the presence of fatigue striations. Bending overload was probably created by a combination of parafunctional forces, bone resorption, posterior location of the implants, and implant diameter.

Aged↗
PubMedDate not supplied

Histologic and histomorphometric analysis of the bone response to machined and sandblasted titanium implants: an experimental study in rabbits.

The aim of this study was to make a comparative analysis between the bone response to machined and sandblasted implants. The sandblasting was done with 150-microns aluminum oxide particles. Under scanning electron microscopic examination, the machined implants presented typical machining grooves, while a very rough, highly irregular surface with depressions and indentations was present on the sandblasted implants. Light microscopy showed a different bone growth pattern on machined (implantopetal growth) and sandblasted (implantofugal growth) implants. No negative effects on the rate of bone growth were observed in spite of the presence of aluminum ions. The histomorphometric analysis showed that sandblasted implants presented, from the third week onwards, a significantly higher contact percentage (P < .0001). These values could point to higher osteoconductivity as a result of the higher surface roughness of sandblasted surfaces.

Aluminum↗