Search PubMedSearch

Biomedical subjects

C Mangano

Publications and source records attributed to C Mangano.

25 records · Page 2Linked to original sources

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

Preparation-induced stability of bioactive apatite coatings.

The stability of the bioactive surface is a major concern in the chemical and physical design of apatite ceramic coatings. In clinical studies, no sintered-hydroxyapatite bulk coating material was present in the surrounding bone tissue after loading periods up to 11 years. In in vitro studies, hydroxyapatite plasma-sprayed coatings dissolved considerably, possibly because of loss of crystallinity during the plasma-spraying procedure. A heat treatment at 600 degrees C reconstituted the crystallinity and promoted the transformation of alpha-tricalcium phosphate into the more stable beta-tricalcium phosphate. Fluorapatite coatings did not lose their crystallinity and had the added advantage of stability as a result of the fluoride ion.

Animals

Light and laser scanning microscopy analysis of hydroxyapatite used in periodontal osseous defects in man: evidence of a different resorption pattern in bone and soft tissues.

Hydroxyapatite (HA) is a highly biocompatible material that recently has been shown to undergo biodegradation. The mechanisms of this phenomenon are unclear, and humoral and cellular events have been thought to be implicated. In the present study HA particles were put into infraosseous defects on teeth that were to be extracted for prosthetic reasons and then retrieved after a 1-year period. The specimens were processed with the cutting grinding system. Results show a very sharp difference of the biodegradation processes, related to the tissues that surround the HA particles. HA in tight contact with mineralized bone showed no evidence of degradation or resorption, while on the contrary, in the areas where bone loose connective tissue was present, it was possible to observe HA crystals detached and scattered in cells cytoplasm or extracellular fluids. This dissolution and resorption phenomenon were observed also by Laser Scanning Microscope (LSM) in fluorescent mode. These differences in degrees of degradation between bone and loose connective tissue could be due to the small amount of interstitial fluid present in mineralized bone and the greater flow of fluid through connective tissue.

Biodegradation, Environmental