Effect of bismuth subgallate (a hemostatic agent) on bone repair; a histologic, radiographic and histomorphometric study in rats.

Bismuth subgallate (BS) is a hemostatic agent used for soft tissue surgery in otorhinolaryngology and dermatology. Its effect on bone repair has not been studied. The present study undertook a quantitative and qualitative evaluation of post-extraction bone healing in the presence of BS. Under intraperitoneal anesthesia, forty male Wistar rats, 80+/-5g body weight, underwent the extraction of both lower first molars. BS was placed in the right post-extraction socket (group E) and the contralateral socket served as control (group C). The animals were killed in groups immediately, 7, 14 and 30 days post-extraction. The mandibles were resected, radiographed and processed for embedding in paraffin. The mesial socket was sectioned along the bucco-lingual axis and stained with hematoxylin-eosin. Total tissue volume and trabecular bone volume of the apical third of the sockets were determined histomorphometrically. At 14 and 30 days post-extraction, group E exhibited bone tissue that resembled that of group C. Histomorphometric analyses showed no statistically significant differences between groups C and E. Bismuth subgallate did not interfere with post-extraction bone healing. Further studies will analyze the effect of this hemostatic agent on bone repair in aniticoagulated rats.

Local effect of titanium implant corrosion: an experimental study in rats.

The aim of this study was to evaluate histologically the biological effect of pitting corrosion and to contribute clinically relevant data on the permanence of titanium metal structures used in osteosynthesis in the body. Commercially pure titanium laminar implants (control) and commercially pure titanium laminar implants with pitting corrosion (experimental) were implanted in the tibiae of rats. At 14 days post-implantation the animals were killed. The tibiae were resected, fixed, radiographed and processed for embedding in methyl methacrylate. Percentage of bone-implant contact and peri-implant bone volume were evaluated. The histological study of the titanium implants submitted to pitting corrosion showed scarce bone-implant contact, it was only present in the areas with no pitting and/or surface alterations. There was a statistically significant lower percentage of bone-implant contact in the experimental group (6%+/-4) than in the control group (26%+/-6) (p<0.001). Products of corrosion in the peri-implant bed, especially around the blood vessels and areas of bone marrow in the metal-tissue interface, were observed. The microchemical analysis of corrosion products revealed the presence of titanium. The adverse local effects caused by pitting corrosion suggest that titanium plates and grids should be used with caution as permanent fixation structures.

A quantitative method to evaluate corrosion products in tissues.

The use of odontological or orthopedic metal implants requires the availability of techniques to estimate tissue response to the corrosion processes. In previous experimental studies we showed the deposition of corrosion products not only locally (Olmedo et al., Implant Dent 2003; 12: 75-80) but also systemically (Olmedo et al., J Mater Sci: Mater in Medic 2002; 13: 793-796) in organs such as liver, spleen and lung. The aim of the present study was to propose a method to quantitatively assess the tissue deposits of the corrosion products of the materials used to manufacture implants. The samples (liver and lung) were embedded in paraffin, and the histological sections were submitted to thickness standardization. The quantitative evaluation of the deposits was performed in an MPM-800 (Carl Zeiss)* microscope. The light microscopy images were digitalized and then analyzed employing the DNA-IBAS-Kontron software that allows for the identification and evaluation of cells loaded with corrosion products (objective 20x). The following end-points were assessed: total field area, number of deposits of corrosion products, partial and total area of the deposits, and the ratio between volume of the deposits and tissue volume. The method proposed serves to quantitatively evaluate, at light microscopy level, the deposition of corrosion products in tissues.

A quantitative method to evaluate corrosion products in tissues

The use of odontological or orthopedic metal implants requires the availability of techniques to estimate tissue response to the corrosion processes. In previous experimental studies we showed the deposition of corrosion products not only locally (Olmedo et al., Implant Dent 2003; 12: 75-80) but also systemically (Olmedo et al., J Mater Sci: Mater in Medic 2002; 13: 793-796) in organs such as liver, spleen and lung. The aim of the present study was to propose a method to quantitatively assess the tissue deposits of the corrosion products of the materials used to manufacture implants. The samples (liver and lung) were embedded in paraffin, and the histological sections were submitted to thickness standardization. The quantitative evaluation of the deposits was performed in an MPM-800 (Carl Zeiss)* microscope. The light microscopy images were digitalized and then analyzed employing the DNA-IBAS-Kontron software that allows for the identification and evaluation of cells loaded with corrosion products (objective 20x). The following end-points were assessed: total field area, number of deposits of corrosion products, partial and total area of the deposits, and the ratio between volume of the deposits and tissue volume. The method proposed serves to quantitatively evaluate, at light microscopy level, the deposition of corrosion products in tissues.

A quantitative method to evaluate corrosion products in tissues.

The use of odontological or orthopedic metal implants requires the availability of techniques to estimate tissue response to the corrosion processes. In previous experimental studies we showed the deposition of corrosion products not only locally (Olmedo et al., Implant Dent 2003; 12: 75-80) but also systemically (Olmedo et al., J Mater Sci: Mater in Medic 2002; 13: 793-796) in organs such as liver, spleen and lung. The aim of the present study was to propose a method to quantitatively assess the tissue deposits of the corrosion products of the materials used to manufacture implants. The samples (liver and lung) were embedded in paraffin, and the histological sections were submitted to thickness standardization. The quantitative evaluation of the deposits was performed in an MPM-800 (Carl Zeiss)* microscope. The light microscopy images were digitalized and then analyzed employing the DNA-IBAS-Kontron software that allows for the identification and evaluation of cells loaded with corrosion products (objective 20x). The following end-points were assessed: total field area, number of deposits of corrosion products, partial and total area of the deposits, and the ratio between volume of the deposits and tissue volume. The method proposed serves to quantitatively evaluate, at light microscopy level, the deposition of corrosion products in tissues.

Histomorphometric study of peri-implant bone healing in the case of nerve injury: an experimental model in rats.

Causes of dental implant failure are of more than passing interest. Within the group of failures caused by iatrogenic factors, injury to the epineurium has been reported to cause the formation of peri-implant fibrous tissue (fibrointegration). The aim of this study was to perform a histomorphometric evaluation of the percentage of osseointegration of implants in contact with the epineurium. Twenty Wistar rats were used. The first lower molars were extracted under xylazine-ketamine anesthesia. A titanium screw implant (diameter, 0.75 mm; length, 2.26 mm) was placed. In the control group (n = 10), apical anchorage of the implant was performed. In the experimental group (n = 10), the apical portion of the implant was placed in contact with the epineurium of the lower mandibular nerve. All animals were killed by ether overdose 30 days after implantation. Radiographs were taken, and the samples were processed for embedding in acrylic resin. Ground sections were obtained along the vestibulo-lingual axis of the mesial alveolus that contained the implant and were stained with toluidine blue. The histologic analysis revealed the presence of bone tissue in the apical portion of the control group samples. In the experimental group, the implant was in contact with the epineurium. There were no statistically significant differences in the percentage of osseointegration between both groups (control group, 39% +/- 9%; experimental group, 38% +/- 10%). The results obtained with this experimental model show that the contact of the implant with the epineurium would not impair the process of osseointegration.

Effect of total body irradiation on peri-implant tissue reaction: an experimental study.

The aim of the present study was to evaluate the osseointegration process under total body irradiation conditions (LD 50/30). Twenty Wistar rats (mean body weight: 90 g) were used. Under ethyl urethane intraperitoneal anesthesia (1 g/kg body weight), the animals were irradiated with a single 700 cGy dose (linear accelerator 6 Mev photons). Four days post irradiation, a titanium laminar implant was placed in the left tibia of each rat. Antibiotic therapy (ceftriaxone) was administered daily post implantation, to prevent infection by radiation. Fourteen days post implantation, the animals were killed by ether overdose. The tibiae were resected, radiographed and processed for embedding in methyl methacrylate. The results showed impaired osteogenesis and absence of osseointegration in experimental tibiae. This could be due to a direct action of total body irradiation on osteogenesis precursor cells. This effect would impair bone formation involved in peri-implant osseointegration processes in this experimental model.

Growth deceleration and bone metabolism in nutritional dwarfing rats.

Nutritional status as well as energy and protein intake are critical regulators of IGF-1 and IGFBP-3 and contribute to the modulation of bone remodeling and formation. The purpose of this study was to investigate on an experimental model with nutritional dwarfing (ND), whether the alterations on body growth velocity, energy metabolism and body composition could affect serum concentrations of IGF-1 and IGFBP-3 and bone (tibiae and mandible) histology and histomorphometry. Twenty-one male weanling Wistar rats (body weight = 38.20 +/- 0.94 g) were randomized to three groups: seven of them were killed at day = 0 (CO, n = 7); control (C, n = 7); and experimental 80 (E80, n = 7). During 4 weeks, C was fed ad libitum with a 1:1 carbohydrate to fat diet. E80 was being underfed with the same diet by 80% and the following parameters were measured: weight (Wt) for length (L) ratio z-score; oxygen consumption (VO2); body composition (BC) by EM-SCAN SA 3000. At t = 28, E80 and C were killed. Serum IGF-1 and IGFBP-3 and bone histology and histomorphometry were performed on C0, E80 and C. E80 showed Wt for L z-score between lean and adequate, a decrease in VO2 according to body proportions, a BC of a delayed puberty individual, IGF-1 and IGFBP-3 decreased by 56 and 53%, respectively. Tibiae's hematopoyetic and adipose bone marrow areas were combined, with sealing trabeculae on metaphyseal areas. This study suggests that there is a relationship among growth deceleration in ND rats and structural alterations on tibiae.

Influence of age and gender on peri-implant osteogenesis. Age and gender on peri-implant osteogenesis.

Among the local and systemic factors affecting bone repair, great interest is focused on age and gender. The aim of this work was to perform a histomorphometric evaluation of peri-implant bone healing response in male and female rats aged 1 and 3 months. Forty Wistar rats were i.p. anesthetized with xylazine and ketamine. A c.p. Ti implant (Implant Vel, Buenos Aires-Argentina) was placed in the right tibia following the method described by Cabrini et al. (Implant Dent 1993; 2:264-267). Group I: (GI, n = 10) female rats aged 1 month; Group II: (GII, n = 10) female rats aged 3 months; Group III: (GIII, n = 10) male rats aged 1 month; Group IV: (GIV, n = 10) male rats aged 3 months. All the animals were killed by ether overdose 30 days post-implantation. The tibiae were resected, radiographed and embedded in methyl-methacrylate. Ground sections perpendicular to the longer axis of the tibia were obtained and stained with toluidine blue. Percentage of osseointegration and peri-implant bone tissue volume were evaluated. No differences in peri-implant bone tissue histology were observed among groups. No statistically significant differences in peri-implant bone volume and percentage of osseointegration were observed between GII (adult females) and GIV (adult males). Peri-implant bone volume and percentage of osseointegration were markedly greater in GIV (adult males) than in GIII (young males) (14 +/- 1 mm2 and 8 +/- 2 mm2) p < 0.01 and (49 +/- 6% and 24 +/- 9%) p < 0.01 respectively. Using this experimental model, differences in peri-implant osteogenesis (bone volume and percentage of osseointegration) associated to gender were only observed in the young rats, and differences associated to age were found between the groups of males.

Influence of age and gender on peri-implant osteogenesis. Age and gender on peri-implant osteogenesis

Among the local and systemic factors affecting bone repair, great interest is focused on age and gender. The aim of this work was to perform a histomorphometric evaluation of peri-implant bone healing response in male and female rats aged 1 and 3 months. Forty Wistar rats were i.p. anesthetized with xylazine and ketamine. A c.p. Ti implant (Implant Vel, Buenos Aires-Argentina) was placed in the right tibia following the method described by Cabrini et al. (Implant Dent 1993; 2:264-267). Group I: (GI, n = 10) female rats aged 1 month; Group II: (GII, n = 10) female rats aged 3 months; Group III: (GIII, n = 10) male rats aged 1 month; Group IV: (GIV, n = 10) male rats aged 3 months. All the animals were killed by ether overdose 30 days post-implantation. The tibiae were resected, radiographed and embedded in methyl-methacrylate. Ground sections perpendicular to the longer axis of the tibia were obtained and stained with toluidine blue. Percentage of osseointegration and peri-implant bone tissue volume were evaluated. No differences in peri-implant bone tissue histology were observed among groups. No statistically significant differences in peri-implant bone volume and percentage of osseointegration were observed between GII (adult females) and GIV (adult males). Peri-implant bone volume and percentage of osseointegration were markedly greater in GIV (adult males) than in GIII (young males) (14 +/- 1 mm2 and 8 +/- 2 mm2) p < 0.01 and (49 +/- 6

) p < 0.01 respectively. Using this experimental model, differences in peri-implant osteogenesis (bone volume and percentage of osseointegration) associated to gender were only observed in the young rats, and differences associated to age were found between the groups of males.

Influence of age and gender on peri-implant osteogenesis. Age and gender on peri-implant osteogenesis.

Among the local and systemic factors affecting bone repair, great interest is focused on age and gender. The aim of this work was to perform a histomorphometric evaluation of peri-implant bone healing response in male and female rats aged 1 and 3 months. Forty Wistar rats were i.p. anesthetized with xylazine and ketamine. A c.p. Ti implant (Implant Vel, Buenos Aires-Argentina) was placed in the right tibia following the method described by Cabrini et al. (Implant Dent 1993; 2:264-267). Group I: (GI, n = 10) female rats aged 1 month; Group II: (GII, n = 10) female rats aged 3 months; Group III: (GIII, n = 10) male rats aged 1 month; Group IV: (GIV, n = 10) male rats aged 3 months. All the animals were killed by ether overdose 30 days post-implantation. The tibiae were resected, radiographed and embedded in methyl-methacrylate. Ground sections perpendicular to the longer axis of the tibia were obtained and stained with toluidine blue. Percentage of osseointegration and peri-implant bone tissue volume were evaluated. No differences in peri-implant bone tissue histology were observed among groups. No statistically significant differences in peri-implant bone volume and percentage of osseointegration were observed between GII (adult females) and GIV (adult males). Peri-implant bone volume and percentage of osseointegration were markedly greater in GIV (adult males) than in GIII (young males) (14 +/- 1 mm2 and 8 +/- 2 mm2) p < 0.01 and (49 +/- 6

and 24 +/- 9

) p < 0.01 respectively. Using this experimental model, differences in peri-implant osteogenesis (bone volume and percentage of osseointegration) associated to gender were only observed in the young rats, and differences associated to age were found between the groups of males.

Histomorphometric study of bone healing around laminar implants in experimental diabetes.

The aim of this study was to evaluate the effects of experimental diabetes on the healing period leading to osseointegration. Wistar rats were injected with a single dose of streptozotocin (STZ); body weight and food intake were assessed every 48 hours. On days 2, 12, 26, and 42 post-STZ, glucemia, plasma hemoglobin, and urea were determined. Twelve days post-STZ, a titanium laminar implant was placed in the right tibia of each rat. Two groups of 20 rats each were killed on days 14 and 30 postimplantation, respectively. Results (ANOVA test) showed STZ-treated rats to have 1) a significant decrease in body weight; 2) an increase in food intake; 3) normal hemoglobin and plasma urea values; 4) a significant increase in glucemia; and 5) a decrease in tibiae length. Microscopic evaluation 14 days postimplantation revealed the presence of woven bone, and, at 30 days, laminar bone was in contact with the implant. Our findings show that, in this model of periimplant bone repair and under the experimental conditions stated herein, STZ-induced diabetes retards periimplant bone healing.

Bone healing under experimental anemia in rats.

The effects of anemia on different physiological parameters have been the object of permanent study. There are no studies in the literature on the effects of this disorder on the process on bone healing. The aim of the present study was to evaluate, histologically and histomorphometrically, the process of osteogenesis in the post-extraction alvcolus of the lower molar, and in the peri-implant environment of rats. Twenty male Wistar rats (body weight (b.w.): 60 +/- 7 g) were grouped into two experimental sets. The control group (n:10) was given 0.5 mL saline solution i.p. The anemic group (n:10) was injected with 6 mg/100 g of b.w. or 3 mg/100 g b.w. phenylhidrazine, a well known hemolytic agent. Under ketamine-xylazine anesthesia the rats were submitted to extraction of the first lower molars, and to implantation in the tibia in keeping with the "laminar test" procedure. Other parameters, i.e. body weight (b.w.), food intake (FI), hematocrit (Htc), and hemoglobinemia (Hb) were monitored every 48 hs. The results showed a reduction in b.w., FI, Htc and Hb in the experimental group. The histological and histomorphometrical data show that the condition of anemia affects osteogenesis quali-quantitatively in the post-extraction alveolus and peri-implant microenvironment. Both bone reparative situations showed that ostegenesis is "sensitive" to anemia and/or the associated conditions, causing a delay in bone healing.

Bone healing under experimental anemia in rats

The effects of anemia on different physiological parameters have been the object of permanent study. There are no studies in the literature on the effects of this disorder on the process on bone healing. The aim of the present study was to evaluate, histologically and histomorphometrically, the process of osteogenesis in the post-extraction alvcolus of the lower molar, and in the peri-implant environment of rats. Twenty male Wistar rats (body weight (b.w.): 60 +/- 7 g) were grouped into two experimental sets. The control group (n:10) was given 0.5 mL saline solution i.p. The anemic group (n:10) was injected with 6 mg/100 g of b.w. or 3 mg/100 g b.w. phenylhidrazine, a well known hemolytic agent. Under ketamine-xylazine anesthesia the rats were submitted to extraction of the first lower molars, and to implantation in the tibia in keeping with the [quot ]laminar test[quot ] procedure. Other parameters, i.e. body weight (b.w.), food intake (FI), hematocrit (Htc), and hemoglobinemia (Hb) were monitored every 48 hs. The results showed a reduction in b.w., FI, Htc and Hb in the experimental group. The histological and histomorphometrical data show that the condition of anemia affects osteogenesis quali-quantitatively in the post-extraction alveolus and peri-implant microenvironment. Both bone reparative situations showed that ostegenesis is [quot ]sensitive[quot ] to anemia and/or the associated conditions, causing a delay in bone healing.

Bone healing under experimental anemia in rats.

The effects of anemia on different physiological parameters have been the object of permanent study. There are no studies in the literature on the effects of this disorder on the process on bone healing. The aim of the present study was to evaluate, histologically and histomorphometrically, the process of osteogenesis in the post-extraction alvcolus of the lower molar, and in the peri-implant environment of rats. Twenty male Wistar rats (body weight (b.w.): 60 +/- 7 g) were grouped into two experimental sets. The control group (n:10) was given 0.5 mL saline solution i.p. The anemic group (n:10) was injected with 6 mg/100 g of b.w. or 3 mg/100 g b.w. phenylhidrazine, a well known hemolytic agent. Under ketamine-xylazine anesthesia the rats were submitted to extraction of the first lower molars, and to implantation in the tibia in keeping with the [quot ]laminar test[quot ] procedure. Other parameters, i.e. body weight (b.w.), food intake (FI), hematocrit (Htc), and hemoglobinemia (Hb) were monitored every 48 hs. The results showed a reduction in b.w., FI, Htc and Hb in the experimental group. The histological and histomorphometrical data show that the condition of anemia affects osteogenesis quali-quantitatively in the post-extraction alveolus and peri-implant microenvironment. Both bone reparative situations showed that ostegenesis is [quot ]sensitive[quot ] to anemia and/or the associated conditions, causing a delay in bone healing.

A histomorphometric study of tissue interface by laminar implant test in rats.

Study of the implant-tissue interface is one of the fundamental issues in implantology, both odontologic and orthopedic. The characteristics of this interface will influence the success or failure of an implant. The aim of the present study was to evaluate histomorphometrically the capacity of different metals to osseointegrate employing laminar implants of zirconium, titanium, aluminum, and zirconium coated with diamond-like carbon. The experimental model herein allowed for the quantitative evaluation of the tissue-implant interface for different metals. The implants were placed in the tibiae of Wistar rats under anesthesia and allowed to remain in situ for a 30-day period. The interfaces of the zirconium and diamond-like coated zirconium implants exhibited better responses than the interface of titanium implants. Aluminum produced a local toxic effect, evidenced by osteoid formation.

Evaluation of bone tissue on metallic implants by energy-dispersive x-ray analysis: an experimental study.

Osseointegration capacity of the different metallic implants depends on several variables. Osseointegration can be evaluated by using different methodologies, such as light microscopy and scanning or transmission electron microscopy. The aim of this study was to develop a qualitative and quantitative method to evaluate the presence of bone tissue on large metallic surfaces. A laminar implant was placed in each tibia of 10 Wistar rats. The animals were killed 30 days after surgery. Tibiae were resected, one for embedding in methyl methacrylate and the other for evaluation by energy-dispersive x-ray analysis. Light microscopy revealed osseointegration. Observation of the implant surface by scanning electron microscopy revealed the presence of a coating on the metallic surface that was rough in some areas and smooth in others. Analysis of the coating by energy-dispersive x-ray analysis showed the presence of Ca and P. Eighty percent (+/- 10%) of the metallic implant surface exhibited bone tissue. After confirmation of the occurrence of osseointegration capacity using light microscopy, the method described here allows qualitative and quantitative evaluation of the bone tissue found on large metallic surfaces.

An experimental model to study implant corrosion.

Corrosion phenomena would appear to play a decisive role in metallic implant long term behaviour. This study presents a method to correlate results obtained in "in vivo" and "in vitro" studies on materials used for metallic implants. Samples of titanium and copper immersed in saline solution (pH 7.4 and 5.2) were used for the "in vitro" study. Implants of these same materials were placed in rat tibiae following the method previously described by Cabrini et al. The animals were killed 14 days post-implantation, the tibiae were resected, radiographed and embedded in acrylic resin. Polarization curves revealed high corrosion in copper implants and low corrosion in titanium implants. It is important to point out that the titanium samples suffered slightly higher corrosion when immersed in a lower pH medium (pH 5.2), as in chronic inflammatory processes. A passive film was found on titanium samples as opposed to the strong corrosion observed in the copper implants. Microscopy revealed osseointegration around titanium implants and a severe inflammatory reaction with abscesses surrounding the copper implants. The method presented herein would allow to correlate "in vivo" and "in vitro" studies on corrosion in different implant materials and establish their relation with cell response.

An experimental model to study implant corrosion

Corrosion phenomena would appear to play a decisive role in metallic implant long term behaviour. This study presents a method to correlate results obtained in [quot ]in vivo[quot ] and [quot ]in vitro[quot ] studies on materials used for metallic implants. Samples of titanium and copper immersed in saline solution (pH 7.4 and 5.2) were used for the [quot ]in vitro[quot ] study. Implants of these same materials were placed in rat tibiae following the method previously described by Cabrini et al. The animals were killed 14 days post-implantation, the tibiae were resected, radiographed and embedded in acrylic resin. Polarization curves revealed high corrosion in copper implants and low corrosion in titanium implants. It is important to point out that the titanium samples suffered slightly higher corrosion when immersed in a lower pH medium (pH 5.2), as in chronic inflammatory processes. A passive film was found on titanium samples as opposed to the strong corrosion observed in the copper implants. Microscopy revealed osseointegration around titanium implants and a severe inflammatory reaction with abscesses surrounding the copper implants. The method presented herein would allow to correlate [quot ]in vivo[quot ] and [quot ]in vitro[quot ] studies on corrosion in different implant materials and establish their relation with cell response.

An experimental model to study implant corrosion.

Corrosion phenomena would appear to play a decisive role in metallic implant long term behaviour. This study presents a method to correlate results obtained in [quot ]in vivo[quot ] and [quot ]in vitro[quot ] studies on materials used for metallic implants. Samples of titanium and copper immersed in saline solution (pH 7.4 and 5.2) were used for the [quot ]in vitro[quot ] study. Implants of these same materials were placed in rat tibiae following the method previously described by Cabrini et al. The animals were killed 14 days post-implantation, the tibiae were resected, radiographed and embedded in acrylic resin. Polarization curves revealed high corrosion in copper implants and low corrosion in titanium implants. It is important to point out that the titanium samples suffered slightly higher corrosion when immersed in a lower pH medium (pH 5.2), as in chronic inflammatory processes. A passive film was found on titanium samples as opposed to the strong corrosion observed in the copper implants. Microscopy revealed osseointegration around titanium implants and a severe inflammatory reaction with abscesses surrounding the copper implants. The method presented herein would allow to correlate [quot ]in vivo[quot ] and [quot ]in vitro[quot ] studies on corrosion in different implant materials and establish their relation with cell response.