Silvana Rizzo - Academia.edu (original) (raw)
Papers by Silvana Rizzo
Stomatologia mediterranea: SM
![Research paper thumbnail of [Osteo-conductive materials: animal experiments and instrumental analysis II]](https://attachments.academia-assets.com/41203393/thumbnails/1.jpg)
](Minerva stomatologica
In daily dental surgery practice, when it is not possible to obtain-enough autogenous bone graft ... more In daily dental surgery practice, when it is not possible to obtain-enough autogenous bone graft to fill bone defects, bone substitutes can be useful for bone regeneration. After a preliminary microscopic examination of histologic samples obtained from semithin sections of the tibias of rats showing no major differences in the results both for the single material and implant time, further studies on five different osteoconductive materials used in oral clinical practice were carried out with microradiography, SEM and X-ray microanalysis. In experimental animals (rats) bone defects 3 mm large were surgically induced in both tibias: one of the defects was filled by bone substitutes and on the other side the bone defect healed naturally. The findings obtained were studied in depth, and allowed to conclude that the materials tested are suitable for the purpose for which they are marketed. Non-demineralized bovine bone showed the best results with a high degree of osteointegration. Howev...
Minerva stomatologica
No data on the resistance to functional loads of bone regenerated by means of guided tissue regen... more No data on the resistance to functional loads of bone regenerated by means of guided tissue regeneration, can be found. In this paper the new-formed bone is analyzed, in cases that see the surgical creation of defects in testing animals. The morphological aspects of perimplant bone, regenerated by means of bone substitutes or not, were evaluated. A coronal defect was created by means of a counter-sink bur. The following step provided for osseointegrated fixtures, with a machined or blasted (TiOblast) surface, to be installed. Some bone defects were filled with Bio-Oss, and covered with resorbable membrane (Vycril), others were left unfilled. The animals were sacrificed after different periods of time (24 and 45 days). Some thick sections (200 microns) underwent then microradiography and were examined with a microscope, under transmitted and polarized light. Other sections, thin (5 microns), were coloured with toluidine blue, Gomori's Stain and Solochrome Cyanine/Congo red. Data ...
Minerva stomatologica
The clinical and histological aspects of gingival hypertrophy due to cyclosporine-A in 10 heart-t... more The clinical and histological aspects of gingival hypertrophy due to cyclosporine-A in 10 heart-transplanted patients are studied. The behaviour to avoid or to limit gingival overgrowth is suggested.
The Anatomical Record
Investigation was performed on healthy and inflamed human gingivae. In the healthy mucosa lymphat... more Investigation was performed on healthy and inflamed human gingivae. In the healthy mucosa lymphatic vessels generally appeared as flattened channels with a reduced lumen. Only in very inflamed tissue were some more evident vessels with a distended wall detectable. Ultrastructurally, most of the vessels had the characteristics of capillaries and they were delimited by a thin and irregular endothelial wall with large intercellular spaces. These observations indicate that in the gingival tissues, which are continuously exposed to inflammatory agents and need a really efficient draining system, the pathway of interstitial exudation and cell migration may include both the lymphatic vessel system and the intercellular spaces of the permeable junctional epithelium.
Minerva stomatologica
Instrumental neutron activation analysis has been used to determine quantitatively the content of... more Instrumental neutron activation analysis has been used to determine quantitatively the content of certain trace elements forming the healthy tooth in a sample of 31 teeth extracted for orthodontic or periodontal reasons.
Minerva stomatologica
Antibiotic prophylaxis in surgical implants has not a consensus in the scientific world. This is ... more Antibiotic prophylaxis in surgical implants has not a consensus in the scientific world. This is due both to reports and statistical studies with contradictory results, both to the risk of severe anaphylactic reactions and the emergence of antibiotic resistance and, finally, to the lack of published RCTs. The purpose of this study is to retrospectively analyze and assess the success of surgical therapy with endosseous implants inserted under antibiotic prophylaxis at the Department of Oral Sciences "S. Palazzi", University of Pavia. The data presented are compared to those published in international literature. The work is complemented by a statistical data analysis in order to propose a statistically valid judgement on the effectiveness of antibiotic prophylaxis in preventing postoperative infections. Retrospective observational study with an average follow-up of 4.5 months, until the abutment connection. Furthermore, after extensive review of the literature, published da...
The Anatomical Record, 1999
Investigation was performed on healthy and inflamed human gingivae. In the healthy mucosa lymphat... more Investigation was performed on healthy and inflamed human gingivae. In the healthy mucosa lymphatic vessels generally appeared as flattened channels with a reduced lumen. Only in very inflamed tissue were some more evident vessels with a distended wall detectable. Ultrastructurally, most of the vessels had the characteristics of capillaries and they were delimited by a thin and irregular endothelial wall with large intercellular spaces. These observations indicate that in the gingival tissues, which are continuously exposed to inflammatory agents and need a really efficient draining system, the pathway of interstitial exudation and cell migration may include both the lymphatic vessel system and the intercellular spaces of the permeable junctional epithelium. Anat Rec 255: 175-179, 1999. 1999 Wiley-Liss, Inc.
Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, 2011
An osteoma is a slow-growing, benign lesion comprising mature bone tissue. Osteomas rarely occur ... more An osteoma is a slow-growing, benign lesion comprising mature bone tissue. Osteomas rarely occur in maxillary bones, with the exception of the maxillary sinuses. Various possible etiologies have been proposed, including congenital anomalies, chronic inflammation, muscular activity, embryogenetic changes, and trauma. Here we present a case of an osteoma of the buccal plate of the mandible at the site where a sports-related traumatic injury occurred 15 years earlier. Both conventional and 3-dimensional x-ray examinations were used for diagnosis and preoperative evaluation of the possible involvement of the adjacent anatomic structures. The lesion was treated surgically without complications and the patient made a complete recovery. Histologic tests confirmed the preoperative diagnosis. A review of the international literature is also presented.
Journal of Periodontology, 2003
Mouthrinses are widely utilized in daily oral and dental hygiene to control plaque. However, most... more Mouthrinses are widely utilized in daily oral and dental hygiene to control plaque. However, most commercially available mouthrinses contain alcohol as an excipient. Most studies have focused on the clinical side effects related to the alcoholic fraction of mouthrinses, overlooking alcohol metabolism in the mouth. Due to this oral enzymatic process, the well-recognized toxic compound acetaldehyde is emitted in the mouth. Since gingival fibroblasts play a key role in oral connective tissue health maintenance, we investigated the effects of different doses of acetaldehyde on human gingival fibroblasts (HGFs) in order to better define the effects of alcohol-containing mouthrinses on oral tissue. Cultured HGFs were exposed to different concentrations of acetaldehyde (10(-4) M to 10(-2) M). The cell adhesion rate was measured after a 3-hour incubation period, and cell viability over a 5-day period. In order to assess the reversibility of the damage produced by acetaldehyde, treatment was interrupted at critical doses (10(-3) M and 3 x 10(-3) M), and cell viability was evaluated on the third and fifth day of incubation. The HGF cytoskeleton was studied by immunocytochemical technique, and internal cell structures were observed with transmission electron microscopy to evaluate the morphological changes due to acetaldehyde. The results showed that acetaldehyde produced a dose- and time-dependent inhibition on cell adhesion and viability, together with disruption of cytoskeletal structures and cytoplasmic organelles. Nevertheless, these quantitative and qualitative damages were reversible when the treatment was interrupted. Although more knowledge is necessary, our results suggest that these deleterious effects may also occur in vivo. Pending further investigations, clinicians should be alerted to the potentially adverse effect of alcohol-containing mouthrinses and, to promote oral health, patients should be warned about improper use of these products.
Journal of Craniofacial Surgery, 2013
Although numerous biomaterials are used for maxillary sinus-lift surgery, the ideal material for ... more Although numerous biomaterials are used for maxillary sinus-lift surgery, the ideal material for such procedures has not yet been identified. Both heterologous and alloplastic bone substitutes have a solely osteoconductive effect and lack the osteoinductive properties of the bone morphogenetic proteins typical of autologous bone. Our group assessed a new alloplastic graft material, poly(lactic-co-glycolic) acid/hydroxyapatite (PLGA/HA), implanted in a human model of maxillary sinus-lift surgery. For this prospective, random, double-blind trial, we used deproteinized bovine bone (DBB) as the comparison material. Radiographic bone vertical height and density were assessed at approximately 28 weeks after grafting using cone-beam computed tomography. The vertical dimension of the regenerated bone was equivalent between the 2 groups. The density of the bone regenerated using PLGA/HA was significantly lower than that obtained with DBB. Despite clinical assessments demonstrating that PLGA/HA has sufficient characteristics for use in sinus-lift surgery, DBB provided greater bone density and an equivalent vertical dimension of grafted bone. Further studies are needed to supplement the radiologic findings with histologic and micromorphometric examinations.
Journal of Biomedical Materials Research, 2003
Fourteen titanium dental implants (Tioblast™) were implanted singly in the proximal tibia of New ... more Fourteen titanium dental implants (Tioblast™) were implanted singly in the proximal tibia of New Zealand rabbits for 120 days. A bone defect was surgically produced and filled with Bio-Oss around six of these implants. After the animals were sacrificed and their organs harvested, bone segments were fixed and methacrylate embedded after the push-in test had been performed. Microradiography was performed on longitudinal sections of the implants, whereas scanning electron microscope analysis was performed on the remaining embedded half-implants using secondary electrons only. The results showed that the implants were apically and coronally surrounded by bone, whether Bio-Oss was used or not. Fractures were evident through the newly formed bone and between the pre-existing and newly formed bone. Some fracture lines propagated through the bone and stopped at the implant surface without continuing along the bone-titanium interface. Detachment between the implant and the bone occurred at the coronal extremity of the implants and along its cervical region. These results highlight the fact that the bone-titanium interface has a high resistance to loading. It exhibited greater resistance than the newly formed bone and seems to behave in a manner similar to the cement lines of osteons.
Clinical Drug Investigation, 2008
generally followed by acute post-operative pain that has been shown to be primarily inflammatory.... more generally followed by acute post-operative pain that has been shown to be primarily inflammatory. Thus, use of NSAIDs in this context is appropriate and has been shown to be effective. Several drugs are employed for this purpose, but no information exists on the reasons why preference is given to one rather than another. The principal objective of this study was to evaluate the pattern of administration of NSAIDs in patients undergoing surgery for impacted third molar extraction. The study also aimed to collect information on the efficacy, onset and duration of the analgesic effect of routinely prescribed NSAIDs and to assess the duration of treatment with these drugs and their tolerability. Methods: This was an observational, multicentre, prospective survey. A total of 616 patients (38% male and 62% female) from the Italian Stomatology , were eligible for the study. Patients were evaluated over the 7 days following surgical extraction. NSAIDs were prescribed according to the normal prescribing habits of the centre and physician involved. The main outcomes of interest in the survey were the efficacy, onset and duration of analgesic effect, duration of therapy, and tolerability of the NSAIDs prescribed. Results: Nimesulide was the most prescribed NSAID (68%), followed by diclofenac, ketoprofen and ibuprofen. Because of the low proportion of patients receiving other NSAIDs, these patients were considered a single treatment group for evaluation purposes. Nimesulide, especially when given before patients started
Biomaterials, 2002
The mechanical stability of the fixture in bone is one of the most important factors for the long... more The mechanical stability of the fixture in bone is one of the most important factors for the long-term reliability of dental implants. This paper focuses on an experimental procedure to evaluate the mechanical properties of the bone surrounding dental implants. The procedure is based on a surgical animal model followed by mechanical tests. The experimental mechanical testing has been used for preliminary investigations on the role played by different parameters such as the healing time and the surgical technique (standard or with regenerative material). The procedure has been evaluated in some preliminary tests on a few specimens. Microradiographic analyses have been performed on the bone surrounding the implants in order to give an interpretation of the bone properties on the basis of the bone morphology and to distinguish the newly formed bone from the pre-existing bone.
Stomatologia mediterranea: SM
Minerva stomatologica
In daily dental surgery practice, when it is not possible to obtain-enough autogenous bone graft ... more In daily dental surgery practice, when it is not possible to obtain-enough autogenous bone graft to fill bone defects, bone substitutes can be useful for bone regeneration. After a preliminary microscopic examination of histologic samples obtained from semithin sections of the tibias of rats showing no major differences in the results both for the single material and implant time, further studies on five different osteoconductive materials used in oral clinical practice were carried out with microradiography, SEM and X-ray microanalysis. In experimental animals (rats) bone defects 3 mm large were surgically induced in both tibias: one of the defects was filled by bone substitutes and on the other side the bone defect healed naturally. The findings obtained were studied in depth, and allowed to conclude that the materials tested are suitable for the purpose for which they are marketed. Non-demineralized bovine bone showed the best results with a high degree of osteointegration. Howev...
Minerva stomatologica
No data on the resistance to functional loads of bone regenerated by means of guided tissue regen... more No data on the resistance to functional loads of bone regenerated by means of guided tissue regeneration, can be found. In this paper the new-formed bone is analyzed, in cases that see the surgical creation of defects in testing animals. The morphological aspects of perimplant bone, regenerated by means of bone substitutes or not, were evaluated. A coronal defect was created by means of a counter-sink bur. The following step provided for osseointegrated fixtures, with a machined or blasted (TiOblast) surface, to be installed. Some bone defects were filled with Bio-Oss, and covered with resorbable membrane (Vycril), others were left unfilled. The animals were sacrificed after different periods of time (24 and 45 days). Some thick sections (200 microns) underwent then microradiography and were examined with a microscope, under transmitted and polarized light. Other sections, thin (5 microns), were coloured with toluidine blue, Gomori's Stain and Solochrome Cyanine/Congo red. Data ...
Minerva stomatologica
The clinical and histological aspects of gingival hypertrophy due to cyclosporine-A in 10 heart-t... more The clinical and histological aspects of gingival hypertrophy due to cyclosporine-A in 10 heart-transplanted patients are studied. The behaviour to avoid or to limit gingival overgrowth is suggested.
The Anatomical Record
Investigation was performed on healthy and inflamed human gingivae. In the healthy mucosa lymphat... more Investigation was performed on healthy and inflamed human gingivae. In the healthy mucosa lymphatic vessels generally appeared as flattened channels with a reduced lumen. Only in very inflamed tissue were some more evident vessels with a distended wall detectable. Ultrastructurally, most of the vessels had the characteristics of capillaries and they were delimited by a thin and irregular endothelial wall with large intercellular spaces. These observations indicate that in the gingival tissues, which are continuously exposed to inflammatory agents and need a really efficient draining system, the pathway of interstitial exudation and cell migration may include both the lymphatic vessel system and the intercellular spaces of the permeable junctional epithelium.
Minerva stomatologica
Instrumental neutron activation analysis has been used to determine quantitatively the content of... more Instrumental neutron activation analysis has been used to determine quantitatively the content of certain trace elements forming the healthy tooth in a sample of 31 teeth extracted for orthodontic or periodontal reasons.
Minerva stomatologica
Antibiotic prophylaxis in surgical implants has not a consensus in the scientific world. This is ... more Antibiotic prophylaxis in surgical implants has not a consensus in the scientific world. This is due both to reports and statistical studies with contradictory results, both to the risk of severe anaphylactic reactions and the emergence of antibiotic resistance and, finally, to the lack of published RCTs. The purpose of this study is to retrospectively analyze and assess the success of surgical therapy with endosseous implants inserted under antibiotic prophylaxis at the Department of Oral Sciences "S. Palazzi", University of Pavia. The data presented are compared to those published in international literature. The work is complemented by a statistical data analysis in order to propose a statistically valid judgement on the effectiveness of antibiotic prophylaxis in preventing postoperative infections. Retrospective observational study with an average follow-up of 4.5 months, until the abutment connection. Furthermore, after extensive review of the literature, published da...
The Anatomical Record, 1999
Investigation was performed on healthy and inflamed human gingivae. In the healthy mucosa lymphat... more Investigation was performed on healthy and inflamed human gingivae. In the healthy mucosa lymphatic vessels generally appeared as flattened channels with a reduced lumen. Only in very inflamed tissue were some more evident vessels with a distended wall detectable. Ultrastructurally, most of the vessels had the characteristics of capillaries and they were delimited by a thin and irregular endothelial wall with large intercellular spaces. These observations indicate that in the gingival tissues, which are continuously exposed to inflammatory agents and need a really efficient draining system, the pathway of interstitial exudation and cell migration may include both the lymphatic vessel system and the intercellular spaces of the permeable junctional epithelium. Anat Rec 255: 175-179, 1999. 1999 Wiley-Liss, Inc.
Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, 2011
An osteoma is a slow-growing, benign lesion comprising mature bone tissue. Osteomas rarely occur ... more An osteoma is a slow-growing, benign lesion comprising mature bone tissue. Osteomas rarely occur in maxillary bones, with the exception of the maxillary sinuses. Various possible etiologies have been proposed, including congenital anomalies, chronic inflammation, muscular activity, embryogenetic changes, and trauma. Here we present a case of an osteoma of the buccal plate of the mandible at the site where a sports-related traumatic injury occurred 15 years earlier. Both conventional and 3-dimensional x-ray examinations were used for diagnosis and preoperative evaluation of the possible involvement of the adjacent anatomic structures. The lesion was treated surgically without complications and the patient made a complete recovery. Histologic tests confirmed the preoperative diagnosis. A review of the international literature is also presented.
Journal of Periodontology, 2003
Mouthrinses are widely utilized in daily oral and dental hygiene to control plaque. However, most... more Mouthrinses are widely utilized in daily oral and dental hygiene to control plaque. However, most commercially available mouthrinses contain alcohol as an excipient. Most studies have focused on the clinical side effects related to the alcoholic fraction of mouthrinses, overlooking alcohol metabolism in the mouth. Due to this oral enzymatic process, the well-recognized toxic compound acetaldehyde is emitted in the mouth. Since gingival fibroblasts play a key role in oral connective tissue health maintenance, we investigated the effects of different doses of acetaldehyde on human gingival fibroblasts (HGFs) in order to better define the effects of alcohol-containing mouthrinses on oral tissue. Cultured HGFs were exposed to different concentrations of acetaldehyde (10(-4) M to 10(-2) M). The cell adhesion rate was measured after a 3-hour incubation period, and cell viability over a 5-day period. In order to assess the reversibility of the damage produced by acetaldehyde, treatment was interrupted at critical doses (10(-3) M and 3 x 10(-3) M), and cell viability was evaluated on the third and fifth day of incubation. The HGF cytoskeleton was studied by immunocytochemical technique, and internal cell structures were observed with transmission electron microscopy to evaluate the morphological changes due to acetaldehyde. The results showed that acetaldehyde produced a dose- and time-dependent inhibition on cell adhesion and viability, together with disruption of cytoskeletal structures and cytoplasmic organelles. Nevertheless, these quantitative and qualitative damages were reversible when the treatment was interrupted. Although more knowledge is necessary, our results suggest that these deleterious effects may also occur in vivo. Pending further investigations, clinicians should be alerted to the potentially adverse effect of alcohol-containing mouthrinses and, to promote oral health, patients should be warned about improper use of these products.
Journal of Craniofacial Surgery, 2013
Although numerous biomaterials are used for maxillary sinus-lift surgery, the ideal material for ... more Although numerous biomaterials are used for maxillary sinus-lift surgery, the ideal material for such procedures has not yet been identified. Both heterologous and alloplastic bone substitutes have a solely osteoconductive effect and lack the osteoinductive properties of the bone morphogenetic proteins typical of autologous bone. Our group assessed a new alloplastic graft material, poly(lactic-co-glycolic) acid/hydroxyapatite (PLGA/HA), implanted in a human model of maxillary sinus-lift surgery. For this prospective, random, double-blind trial, we used deproteinized bovine bone (DBB) as the comparison material. Radiographic bone vertical height and density were assessed at approximately 28 weeks after grafting using cone-beam computed tomography. The vertical dimension of the regenerated bone was equivalent between the 2 groups. The density of the bone regenerated using PLGA/HA was significantly lower than that obtained with DBB. Despite clinical assessments demonstrating that PLGA/HA has sufficient characteristics for use in sinus-lift surgery, DBB provided greater bone density and an equivalent vertical dimension of grafted bone. Further studies are needed to supplement the radiologic findings with histologic and micromorphometric examinations.
Journal of Biomedical Materials Research, 2003
Fourteen titanium dental implants (Tioblast™) were implanted singly in the proximal tibia of New ... more Fourteen titanium dental implants (Tioblast™) were implanted singly in the proximal tibia of New Zealand rabbits for 120 days. A bone defect was surgically produced and filled with Bio-Oss around six of these implants. After the animals were sacrificed and their organs harvested, bone segments were fixed and methacrylate embedded after the push-in test had been performed. Microradiography was performed on longitudinal sections of the implants, whereas scanning electron microscope analysis was performed on the remaining embedded half-implants using secondary electrons only. The results showed that the implants were apically and coronally surrounded by bone, whether Bio-Oss was used or not. Fractures were evident through the newly formed bone and between the pre-existing and newly formed bone. Some fracture lines propagated through the bone and stopped at the implant surface without continuing along the bone-titanium interface. Detachment between the implant and the bone occurred at the coronal extremity of the implants and along its cervical region. These results highlight the fact that the bone-titanium interface has a high resistance to loading. It exhibited greater resistance than the newly formed bone and seems to behave in a manner similar to the cement lines of osteons.
Clinical Drug Investigation, 2008
generally followed by acute post-operative pain that has been shown to be primarily inflammatory.... more generally followed by acute post-operative pain that has been shown to be primarily inflammatory. Thus, use of NSAIDs in this context is appropriate and has been shown to be effective. Several drugs are employed for this purpose, but no information exists on the reasons why preference is given to one rather than another. The principal objective of this study was to evaluate the pattern of administration of NSAIDs in patients undergoing surgery for impacted third molar extraction. The study also aimed to collect information on the efficacy, onset and duration of the analgesic effect of routinely prescribed NSAIDs and to assess the duration of treatment with these drugs and their tolerability. Methods: This was an observational, multicentre, prospective survey. A total of 616 patients (38% male and 62% female) from the Italian Stomatology , were eligible for the study. Patients were evaluated over the 7 days following surgical extraction. NSAIDs were prescribed according to the normal prescribing habits of the centre and physician involved. The main outcomes of interest in the survey were the efficacy, onset and duration of analgesic effect, duration of therapy, and tolerability of the NSAIDs prescribed. Results: Nimesulide was the most prescribed NSAID (68%), followed by diclofenac, ketoprofen and ibuprofen. Because of the low proportion of patients receiving other NSAIDs, these patients were considered a single treatment group for evaluation purposes. Nimesulide, especially when given before patients started
Biomaterials, 2002
The mechanical stability of the fixture in bone is one of the most important factors for the long... more The mechanical stability of the fixture in bone is one of the most important factors for the long-term reliability of dental implants. This paper focuses on an experimental procedure to evaluate the mechanical properties of the bone surrounding dental implants. The procedure is based on a surgical animal model followed by mechanical tests. The experimental mechanical testing has been used for preliminary investigations on the role played by different parameters such as the healing time and the surgical technique (standard or with regenerative material). The procedure has been evaluated in some preliminary tests on a few specimens. Microradiographic analyses have been performed on the bone surrounding the implants in order to give an interpretation of the bone properties on the basis of the bone morphology and to distinguish the newly formed bone from the pre-existing bone.