Examining the Impact of Acute Binge Alcohol Consumption on Trabecular Morphometry and Tensile Strength in Adolescent Sprague Dawley Rat Mandibles / Análisis del Impacto del Consumo Excesivo de Alcohol en la Morfometría Trabecular y la Resistencia a la Tracción en Mandíbulas de Ratas Adolescentes Sprague Dawley

SUMMARY: Underage drinking has become a major public concern having a negative impact on the growth and development of the skeleton. Peak bone mass is attained during adolescence hence the aim of the study was to investigate the effect of acute binge alcohol consumption on trabecular morphometry and tensile strength of the adolescent mandible in the Sprague Dawley (SD) rat. The study comprised of 24 SD rats, aged 7 weeks, placed into either the alcohol-exposed [n=12 (6 males and 6 female)] or pair-fed control group [n=12 (6 male and 6 female)]. The treatment of the groups was as follows; the alcohol exposed group and the pair-fed control were administered a single daily dose of 3 g/kg of 20 % alcohol 3 days a week (alternate days) for 7 days and a caloric equivalent dose of maltose dextrin via oral gavage, respectively. The animals were terminated on day 7 via pentobarbital injection. The mandibles were harvested and scanned using a Nikon XTH 255L 3D-microCT scanner (Nikon Metrology, Leuven, Belgium), and biomechanical tests were done using a Shimadzu universal tensile strength testing machine (China). Following scanning and reconstruction, the trabecular morphometry was assessed using Volume Graphics Studio® software. A 3-point bending test was used to evaluate the tensile strength of the bone. Findings from our study showed changes in some trabecular parameters in the female alcohol-exposed group, while the male groups remained unaffected. No changes in tensile strength were seen when comparing male pair-fed control and alcohol-exposed groups and when comparing female pair-fed control and alcohol-exposed groups. Trabecular and tensile strength differences were observed between the sexes when comparing male pair-fed control and alcohol-exposed groups to female pair-fed control and alcohol-exposed groups. These findings do suggest that acute binge alcohol consumption has detrimental effects on the bone micro-architecture in female alcohol-exposed rats and that differences are seen between the sexes.

El consumo de alcohol entre menores de edad se ha convertido en una importante preocupación pública que tiene un impacto negativo en el crecimiento y desarrollo del esqueleto. La masa ósea máxima se alcanza durante la adolescencia, por lo que el objetivo del estudio fue investigar el efecto del consumo excesivo de alcohol en forma aguda sobre la morfometría trabecular y la resistencia a la tracción de la mandíbula en ratas adolescente Sprague Dawley (SD). El estudio estuvo compuesto por 24 ratas, de 7 semanas de edad, colocadas en el grupo control expuesto al alcohol [n=12 (6 machos y 6 hembras)] y alimentado en parejas [n=12 (6 machos y 6 hembras)]. El tratamiento de los grupos fue el siguiente; al grupo expuesto al alcohol y al control alimentado en parejas se les administró una dosis única diaria de 3 g/kg de alcohol al 20 % 3 días a la semana (días alternos) durante 7 días y una dosis equivalente calórica de maltosa dextrina mediante sonda oral, respectivamente. Los animales fueron sacrificados el día 7 mediante inyección de pentobarbital. Las mandíbulas se recolectaron y se escanearon utilizando un escáner 3D-microCT Nikon XTH 255L (Nikon Metrology, Lovaina, Bélgica), y las pruebas biomecánicas se realizaron utilizando una máquina de prueba de resistencia a la tracción universal Shimadzu (China). Después del escaneo y la reconstrucción, la morfometría trabecular se evaluó utilizando el software Volume Graphics Studio®. Se utilizó una prueba de flexión de 3 puntos para evaluar la resistencia a la tracción del hueso. Los hallazgos de nuestro estudio mostraron cambios en algunos parámetros trabeculares en el grupo de hembras expuestas al alcohol, mientras que los grupos de machos no se vieron afectados. No se observaron cambios en la resistencia a la tracción al comparar los grupos control de machos alimentados en parejas y los grupos expuestos al alcohol y al comparar los grupos control de las hembras alimentadas en parejas y los grupos expuestos al alcohol. Se observaron diferencias trabeculares y de resistencia a la tracción entre los sexos al comparar los grupos control de los machos alimentados en parejas y expuestos al alcohol con los grupos de control de hembras alimentadas en parejas y expuestas al alcohol. Estos hallazgos sugieren que el consumo excesivo de alcohol tiene efectos perjudiciales sobre la microarquitectura ósea en ratas hembras expuestas al alcohol y que se observan diferencias entre los sexos.

Effect of a Dose-Dependent Administration of Binge Alcohol on the Mandible in the Adolescent Sprague Dawley Rat / Efecto de una Administración Dosis-Dependiente de Alcohol en Exceso en la Mandíbula de la Rata Sprague Dawley Adolescente

SUMMARY: Binge drinking in adolescents has a negative effect on the developing skeleton and the attainment of peak bone mass. Our study aimed to examine the effect of binge drinking on the growth and functional integrity of the adolescent Sprague Dawley rat mandible and to determine if a dosage of 1.5 g/kg is sufficient to produce a binge-model of consumption. A total of eight 7-week-old adolescent (male) Sprague Dawley rats were randomly placed into 4 groups with two rats each: 1-week alcohol-exposed rats, 1-week pair- fed control rats, 4-week alcohol-exposed rats and 4-week pair-fed control rats. The alcohol exposed groups were administered a single daily dose via oral gavage of 1.5 g/kg of 20 % alcohol 3 days a week (alternate days) for 7 or 28 days. The pair-fed control groups were administered a caloric equivalent dose of maltose dextrin via oral gavage on the same days as the alcohol-exposed rats. The one-week alcohol exposed, and control rats were terminated on day 7 and the four-week alcohol exposed and control rats on day 28. The mandibles were dissected out and osteometric measurements determined using a digital vernier caliper. Bones were scanned using a 3D-microCT scanner (Nikon XTH 255L). Biomechanical tests were done using a Shimadzu universal testing machine. Differences observed were regarding mandibular osteometry, which showed a reduced height in the central portion of the alveolar bone (Al'-Me), and an increase in the height of the condylar head (Cd-Ag) in the 1-week alcohol-exposed rats when compared to the 1-week pair-fed control rats. No other differences were noted. Lack of significant changes seen between the alcohol and pair-fed control groups in both acute binge and chronic binge exposed rats is likely due to the low dose of alcohol administered to the rats in the study thus a higher dose is proposed.

El consumo excesivo de alcohol en adolescentes tiene un efecto negativo en el desarrollo del esqueleto y en la consecución de la masa ósea máxima. Nuestro estudio tuvo como objetivo examinar el efecto del consumo excesivo de alcohol sobre el crecimiento y la integridad funcional de la mandíbula de la rata adolescente Sprague Dawley y determinar si una dosis de 1,5 g/kg es suficiente para producir un modelo de consumo compulsivo. Un total de ocho ratas Sprague Dawley adolescentes (machos) de 7 semanas de edad se colocaron aleatoriamente en 4 grupos con dos ratas cada uno: ratas expuestas al alcohol durante 1 semana, ratas de control alimentadas en parejas durante 1 semana, ratas expuestas al alcohol durante 4 semanas, y ratas de control alimentadas en parejas durante 4 semanas. A los grupos expuestos al alcohol se les administró una dosis única diaria mediante sonda oral de 1,5 g/kg de alcohol al 20 % 3 días a la semana (días alternos) durante 7 o 28 días. A los grupos de control alimentados por parejas se les administró una dosis calórica equivalente de maltosa dextrina mediante sonda oral los mismos días que a las ratas expuestas al alcohol. Las ratas expuestas al alcohol durante una semana, las ratas de control al día 7, las ratas expuestas al alcohol durante cuatro semanas y las ratas de control al día 28. Se diseccionaron las mandíbulas y se determinaron las mediciones osteométricas utilizando un calibre vernier digital. Los huesos se escanearon utilizando un escáner 3D-microCT (Nikon XTH 255L). Las pruebas biomecánicas se realizaron utilizando una máquina de pruebas universal Shimadzu. Las diferencias observadas se relacionaron con la osteometría mandibular, que mostró una altura reducida en la porción central del hueso alveolar (Al'-Me) y un aumento en la altura de la cabeza condilar (Cd-Ag) en las ratas expuestas al alcohol durante una semana, en comparación con las ratas control alimentadas en parejas durante una semana. No se observaron otras diferencias. La falta de diferencias significativas entre los grupos de alcohol y de control alimentados en parejas expuestas a ebriedad aguda y ebriedad crónica, probablemente se deba a la baja dosis de alcohol administrada a las ratas en el estudio, por lo que se propone una dosis más alta.

Bisphophonate alterations of the jaw bones in individuals with multiple myeloma.

OBJECTIVES: To verify quantitative differences of the mandibular cortical and trabecular bone between patients with multiple myeloma (MM) under bisphosphonate (BP) therapy and a control group never exposed to BP. METHODS: Clinical and demographic characteristics were collected through medical records and interviews. Mandibular cortical thickness (MCT) and fractal dimension (FD) were measured on cone beam computed tomography (CBCT) images, on the molar region, in both groups. Additionally, FD was measured on periapical digital intraoral radiography and results were compared to CBCT measurements. RESULTS: There were 33 patients with MM under BP therapy and 28 controls, with no significant differences in gender and age between groups. Pamidronate was used by all MM patients, either associated or not to other types of BP. The median MCT was higher in MM group exposed to BP (5.20 mm) than in controls (3.50 mm, p < 0.001). There were no significant differences in the median FD between patients in the MM group and controls, on CBCT (0.95 vs 0.90, p = 0.814) and periapical digital intraoral radiography (0.98 vs 0.96, p = 0.963), respectively, even when more than one type of BP was used. CONCLUSIONS: The MCT represents an useful tool in the detection of bone dimensional changes caused by BP, in patients with MM. Additional studies are necessary to improve the knowledge on the quantitative evaluation of trabecular jaw bone, in individuals with MM, under BP therapy.

Effects of different pre-operative doses of dexamethasone on alveolar repair in rats.

Dexamethasone has been widly used in oral and maxillofacial surgery for controlling of postoperative surgical inflammation. Despite its clinical effectiveness, several studies have demonstrated the negative impact of this drug on the healing of soft and hard tissues. This study aimed to assess the effects of different pre-operative doses of dexamethasone on alveolar repair. Sixty rats were divided into four groups of 15 animals each. Single pre-operative doses of dexamethasone equivalent to human doses of 4 mg (Group 4 mg), 8 mg (Group 8 mg), and 12 mg (Group 12 mg), calculated by allometric dose extrapolation, were administered; and rats in the Control Group were injected with saline solution. The animals were anesthetized, and their left mandibular first molars (M1) were removed. After three, seven, and 40 days, 5 animals from each group were euthanized, and bone samples of M1 alveolus were collected for radipgraphic, histomorphological and histometric evaluation of the early and late phases of alveolar healing. At three days, Group 12 mg presented reduced radiographic density, percentage of collagen, and connective matrix compared with the Control Group. At 7 days, the percentage of bone was increased in the Control Group compared to Groups 8 mg and 12 mg (P < 0.05). It can be concluded that a single pre-operative dose of 12 mg of dexamethasone affected the early stages of alveolar repair in rats.

Evaluation of mandibular morphometry in the bisphosphonate users / Evaluación de la morfometría mandibular en los usuarios de bifosfonatos

This study aimed to evaluate the effects of bisphosphonates on the mandibular bone. Bisphosphonates are drugs which are commonly used in the treatment of many diseases related to bone metabolism such as osteoporosis, breast cancer capable of bone metastasis, prostate and lung cancer and bone cancer such as multiple myeloma. Our study group consisted of a total of 100 panoramic radiographs which were obtained from the examinations of 50 individuals using bisphosphonate and 50 individuals in the control group who applied for routine dental examination to the Department of Oral and Maxillofacial Radiology of Akdeniz University Dentistry Faculty between years 2015 and 2016.The calculations of the mandibular cortical thickness (MCT), mandibular cortical index (MCI), panoramic mandibular index (PMI), condylar angle (CA), gonial angle (GA), antegonial angle (AGA), antegonial depth (AGD) and antegonial index (AGI) were made for each patient. It was found that both left and the right MCT and only the left PMI were affected by age. Only the left AGA and both the left and right MCT and AGD were affected by gender. The left and right AGI measurements of the patients using bisphosphonates were statistically lower than those of the individuals in the control group. Our results suggested that bisphosphonates had various effects on the jaw bones. However, further comprehensive studies need to be made to evaluate the longterm effect of bisphosphonates on bone metabolism.

Este estudio tuvo como objetivo evaluar los efectos de los bifosfonatos en el hueso mandibular. Los bifosfonatos son medicamentos que se usan comúnmente en el tratamiento de muchas enfermedades relacionadas con el metabolismo óseo, como la osteoporosis, el cáncer de mama, metástasis óseas, cáncer de próstata y pulmón y el cáncer de hueso como el mieloma múltiple. Nuestro grupo de estudio consistió en un total de 100 radiografías panorámicas que se obtuvieron de los exámenes de 50 individuos que utilizaron bisfosfonato y 50 individuos en el grupo de control que solicitaron un examen dental de rutina al Departamento de Radiología Oral y Maxilofacial de la Facultad de Odontología de la Universidad de Akdeniz, entre los años 2015 y 2016. En cada paciente se realizaron los cálculos del grosor cortical mandibular (GCM), índice cortical mandibular (ICM), índice mandibular panorámico (IMP), ángulo condilar (AC), ángulo gonial (AG), ángulo antegonial (AAG), profundidad antegonial ( PAG) y el índice antegonial (IAG). Se encontró que tanto el GCM izquierdo como el derecho y solo el IMP izquierdo estaban afectados por la edad. Solo el AAG izquierdo y el GCM izquierdo y derecho y el AGD fueron afectados de acuerdo al sexo. Las mediciones de IAG izquierdo y derecho de los pacientes que utilizan bifosfonatos fueron estadísticamente más bajas que las de los individuos en el grupo de control. Nuestros resultados sugirieron que los bifosfonatos tienen varios efectos en los huesos de la mandíbula. Sin embargo, es necesario realizar estudios más exhaustivos para evaluar el efecto a largo plazo de los bifosfonatos en el metabolismo óseo.

Mandibular Bone Loss after Masticatory Muscles Intervention with Botulinum Toxin: An Approach from Basic Research to Clinical Findings.

The injection of botulinum toxin type A (BoNT/A) in the masticatory muscles, to cause its temporary paralysis, is a widely used intervention for clinical disorders such as oromandibular dystonia, sleep bruxism, and aesthetics (i.e., masseteric hypertrophy). Considering that muscle contraction is required for mechano-transduction to maintain bone homeostasis, it is relevant to address the bone adverse effects associated with muscle condition after this intervention. Our aim is to condense the current and relevant literature about mandibular bone loss in fully mature mammals after BoNT/A intervention in the masticatory muscles. Here, we compile evidence from animal models (mice, rats, and rabbits) to clinical studies, demonstrating that BoNT/A-induced masticatory muscle atrophy promotes mandibular bone loss. Mandibular bone-related adverse effects involve cellular and metabolic changes, microstructure degradation, and morphological alterations. While bone loss has been detected at the mandibular condyle or alveolar bone, cellular and molecular mechanisms involved in this process must still be elucidated. Further basic research could provide evidence for designing strategies to control the undesired effects on bone during the therapeutic use of BoNT/A. However, in the meantime, we consider it essential that patients treated with BoNT/A in the masticatory muscles be warned about a putative collateral mandibular bone damage.

The effect of the new hemostatic agent Ostene on bone healing: an experimental study in rabbits

Introduction: Ostene is a water-soluble wax-like alkylene oxide copolymer preparation for use as a mechanical hemostatic agent. this study aims to evaluate the effects of Ostene on bone healing. materials and methods: twenty albino rabbits were divided into four groups according to post-treatment follow-up (24 hr, 3 days, 7 days, 14 days) with five rabbits in each group. each rabbit in all groups was treated with two study materials (Ostene and Gelfoam). three holes were made in the mandibular bone of each rabbit using 5mm surgical bur; two holes were made on right side: one for testing Ostene and another for Gelfoam. a third hole, on the left side of mandible, was not treated, and was used as a control. finally, the incision was closed. the specimens were collected at different days post-treatment and examined by histopathology. result and discussion: this study showed that there is a significant difference (p-value≤ 0.05) between the Ostene group and the other groups (Gelfoam and control). at 24 hr post intervention, there is a significant difference in osteoblast cell formation (p-value=0.03), and osteoclast cell formation (p-value=0.05). new blood vessel formation, osteoblast and osteoclast cell formation for Ostene group at 3 days post-intervention were also significantly different (p-values = 0.05, 0.03, 0.04, respectively). at 7 days post-intervention p-values were 0.05 for osteoblast formation and 0.04 for osteoclast formation, respectively. after 14 days of healing p-value for osteoblast cell formation in the Ostene group was 0.05 and 0.04 for osteoclast cell formation. conclusions: the bone hemostatic agent Ostene is an effective at enhancing osteogenesis by initiating proliferation of osteoblast and osteoclast cells.

Systemic melatonin application increases bone formation in mandibular distraction osteogenesis.

This study aimed to investigate the effects of different doses of systemic melatonin application on new bone formation during mandibular distraction osteogenesis (DO) in rats. Mandibular DO was performed on 30 adult female Sprague-Dawley rats, which were randomly divided into three groups: control group (CNT), melatonin dose 1 (MLT-D1), and melatonin dose 2 (MLT-D2). A five-day latent waiting period and a ten-day distraction phase followed the surgery. After the surgery, rats from the MLT-D1 and MLT-D2 groups received 25 and 50 mg/kg melatonin, respectively, at 7, 14, 21, 28, and 35 days. The animals were euthanised 28 days after distraction, i.e. at 43 days after surgery. Histological and histomorphometric analyses revealed that the distracted bone area was completely filled with new bone formation in all three groups. The MLT-D2 group exhibited the most new bone formation, followed by MLT-D1 and CNT. The melatonin groups had more osteoclasts than the CNT (p < 0.05). The number of osteoblasts was higher in the melatonin groups than in the CNT group, and the MLT-D2 had more osteoclasts than the MLT-D1 group (p < 0.05). Finally, the osteopontin (OPN) and vascular endothelial growth factor (VEGF) levels were higher in the melatonin groups than in the CNT group, and the MLT-D2 had higher OPN and VEGF levels than the MLT-D1 (p < 0.05). This study suggests that systemic melatonin application could increase new bone formation in DO.

Chronic Exposure to Fluoride During Gestation and Lactation Increases Mandibular Bone Volume of Suckling Rats.

We aimed to investigate the effect of maternal exposure to NaF on mandibular bone microarchitecture and phosphocalcic plasma parameters of the offspring. For this purpose, 10-, 15-, and 21-day-old pups (n = 6-8 per group) from two groups of mothers, control and NaF 50mg/L treated dams, were used. Plasma calcium (Ca) and phosphorus (P) levels and alkaline phosphatase activity (ALP) were measured. Fluoride concentration (F-) in bone and in stomach content was measured using potentiometry after isothermal distillation. Morphometric, histological, and histomorphometric analyses of the jaw bones were performed. Plasma Ca and P levels and ALP activity increased in 10-day and decreased in 21-day-old pups from NaF-treated mothers. Fluoride concentration in stomach content samples of 15- and 21-day-old nursing pups from mothers exposed to NaF in their drinking water was higher compared to that observed in control dam offspring. Mandibular F- content was higher in 21-day-old pups born to F--exposed dams compared to those observed in age-matched control pups. Mandibular area increased in 21-day-old pups born to treated mothers as compared to controls. Mandibular bone volume BV/TV (%) was higher in offspring from NaF-exposed dams than in controls at all the studied times. The increase in bone volume after exposure to F- was concomitant with the increase in trabecular thickness and the decrease in trabecular separation. Altogether, our results showed that exposure to NaF during gestation and lactation increased mandibular area and bone volume of pups, with concomitant changes in phosphocalcic parameters associated with the bone modeling process.

Evaluation of Mandibular Bone After Dental Extraction in Rats Treated With Antiresorptive Drugs.

PURPOSE: Zoledronic acid (ZOL) and denosumab (Dmab) are commonly used to treat bone pathologies. Because these drugs suppress bone metabolism, this study sought to compare their effect on bone repair after tooth extraction. MATERIALS AND METHODS: Four-week-old male Wistar rats were randomly assigned to 1 of 3 groups: ZOL 0.125 mg/kg, Dmab 0.25 mg/kg, or saline solution 10 mL/kg (control). After 1 week of treatment, the first left molar was extracted; the rats were euthanized at 28 days. The jaws were removed and photographed for macroscopic analysis of wound healing and then subjected to tomographic and histologic analyses. Immunohistochemistry was carried out against the receptor activator of nuclear factor-κB ligand (RANKL) and osteoprotegerin (OPG). RESULTS: No difference in wound healing, presence of inflammatory infiltrate and bone sequestration, or osteocyte expression of RANKL and OPG was found among groups. Tomographic analysis showed that the ZOL group had less alveolar resorption and more complete alveolar repair compared with the other groups. There was a statistically significant difference in the OPG marker in the control (P = .008) and ZOL (P = .05) groups when comparing the extracted and non-extracted sides. CONCLUSION: Systemic use of ZOL can improve alveolar bone healing; however, the potential risk for the development of osteonecrosis should be considered. Higher expression of OPG seems to be associated with the control of osteoclastogenesis during bone repair.

Systemic melatonin application increases bone formation in mandibular distraction osteogenesis

Abstract This study aimed to investigate the effects of different doses of systemic melatonin application on new bone formation during mandibular distraction osteogenesis (DO) in rats. Mandibular DO was performed on 30 adult female Sprague-Dawley rats, which were randomly divided into three groups: control group (CNT), melatonin dose 1 (MLT-D1), and melatonin dose 2 (MLT-D2). A five-day latent waiting period and a ten-day distraction phase followed the surgery. After the surgery, rats from the MLT-D1 and MLT-D2 groups received 25 and 50 mg/kg melatonin, respectively, at 7, 14, 21, 28, and 35 days. The animals were euthanised 28 days after distraction, i.e. at 43 days after surgery. Histological and histomorphometric analyses revealed that the distracted bone area was completely filled with new bone formation in all three groups. The MLT-D2 group exhibited the most new bone formation, followed by MLT-D1 and CNT. The melatonin groups had more osteoclasts than the CNT (p < 0.05). The number of osteoblasts was higher in the melatonin groups than in the CNT group, and the MLT-D2 had more osteoclasts than the MLT-D1 group (p < 0.05). Finally, the osteopontin (OPN) and vascular endothelial growth factor (VEGF) levels were higher in the melatonin groups than in the CNT group, and the MLT-D2 had higher OPN and VEGF levels than the MLT-D1 (p < 0.05). This study suggests that systemic melatonin application could increase new bone formation in DO.

Effect of organic silicon, methylsulfonylmethane, and glucosamine sulfate in mandibular bone defects in rats.

Organic silicon (OS), glucosamine sulfate (GS), and methylsulfonylmethane (MSM) have been related to bone and connective tissue health and have been considered as basic therapy for osteoarthrosis disorders. Therefore, the aim was to analyze the effect of the association of these three components in mandibular bone defects in rats. Nine rats were used for histocompatibility test. In each animal was implanted the composition (70% OS, 15% GS, 15% MSM) and gutta percha (control) under the dorsal subcutaneous tissue. The samples were collected at 7, 14, and 21 days post-surgery and inflammatory events analyzed. In sequence, the composition was engrafted in mandibular bone defects of nine rats; bone defects without treatment were the control group. Analyses were performed at 7, 14, and 28 days post-surgery and samples were evaluated by scanning electron microscopy (SEM). For the histocompatibility test, both groups had a moderate inflammatory process at 7 days post-surgery and mild inflammatory process at 14 and 21 days. But in SEM analysis, the composition promotes an extensive reabsorption in cortical and crest alveolar bone, and great tooth root reabsorption. In conclusion, although the composition had positive result in the histocompatibility test, its direct application in mandibular bone defects caused intense resorption.

Curcumin photodynamic effect in the treatment of the induced periodontitis in rats.

This study assessed the effect of curcumin as a photosensitizer in antimicrobial photodynamic therapy (aPDT) for the treatment of induced periodontitis in rats. Periodontitis was induced via a ligature around the mandibular first molar on the left side of 96 rats. The ligature was removed 7 days later, and the animals were randomized into four groups: NT, no local treatment; CUR, irrigation with curcumin solution (40 µM); LED, irradiation with a light-emitting diode (LED, InGaN, 465-485 nm, 200 mW/cm2, 60 s); and aPDT, irrigation with curcumin solution (40 µM) followed by irradiation with LED. Eight animals from each group were euthanized at 7, 15, and 30 days post-treatment. Treatments were assessed using alveolar bone loss (ABL) in the furcation region using histological, histometric, and immunohistochemical analyses. Rats treated with aPDT exhibited less ABL at 7 days compared to the NT group, moderate pattern immunolabeling for osteoprotegerin at 30 days, and a pattern of immunolabeling for RANKL from moderate to low. Treatments resulted in smaller numbers of TRAP-positive cells compared to the NT group. aPDT as monotherapy using curcumin as a photosensitizer and LED as the light source was effective in the treatment of induced periodontitis in rats.

Meloxicam as a Radiation-Protective Agent on Mandibles of Irradiated Rats.

This study evaluated the action of ionizing radiation and the possible radioprotective effect of the non-steroidal anti-inflammatory drug meloxicam on the bone physiology of rat mandibles by assessing the alveolar socket healing and bone strength. Forty male Wistar rats were divided in 4 groups (n=10): control (CG), irradiated (IG), meloxicam (MG), meloxicam irradiated (MIG). A dose of 0.2 mg/kg meloxicam was administered to MG and MIG. After this, IG and MIG were irradiated with 15 Gy radiation dose in the mandible. Forty days after the above procedures, the mandibular first molars were extracted and the animals were killed after 15 or 30 days (n=5). Micro-computed tomography and bending test were used to evaluate alveolar socket healing and bone strength, respectively. At 15 days, bone volume, bone volume fraction and trabecular thickness were higher in the CG and MG than in the IG and MIG; and trabecular separation was higher in the IG compared with the others. At 30 days, there was a difference only in trabecular separation, which was higher in IG than in CG and MG, and MIG did not differ from the others. Bone strength was lower in IG compared with CG and MG, and MIG did not differ from the others. In conclusion, the ionizing radiation affected the bone physiology of rat mandibles, delaying the alveolar socket healing and reducing the bone strength. Moreover, the meloxicam had a positive effect on the trabecular separation in alveolar socket healing and on the bone strength.

Mechanical mandible competence in rats with nutritional growth retardation.

OBJECTIVE: In order to provide a better understanding of the sympathetic nervous system as a negative regulator of bone status, the aim of the study was to establish the biomechanical mandible response to different doses of a ß-adrenergic antagonist such as propranolol (P) in a stress-induced food restriction model of growth retardation. METHODS: Rats were assigned to eight groups: Control (C), C+P3.5 (CP3.5), C+P7 (CP7), C+P14 (CP14), NGR, NGR+P3.5 (NGRP3.5), NGR+P7 (NGRP7) and NGR+P14 (NGRP14). C, CP3.5, CP7 and CP14 rats were freely fed with the standard diet. NGR, NGRP3.5, NGRP7 and NGRP14 rats received, for 4 weeks (W4), 80% of the amount of controls food consumed. Propranolol 3.5, 7 and 14mg/kg/day was injected ip 5days per week in CP3.5 and NGRP3.5, CP7 and NGRP7, CP14 and NGRP14, respectively. At W4, zoometry, mandible morphometry, static histomorphometric and biomechanical competence were performed. RESULTS: A dose of Propranolol 7mg/kg/day induced interradicular bone volume accretion reaching a mandible stiffness according to chronological age. CONCLUSION: These findings evidenced that sympathetic nervous system activity is a negative regulator of mandible mechanical competence in the nutritional growth retardation model. Propranolol 7mg/kg/day, under the regimen usage, seems to be appropriate to blockade SNS activity on mandible mechanical performance in NGR rats, probably associated to an effect on bone mechanostat system ability to detect disuse mode as an error.

Meloxicam as a Radiation-Protective Agent on Mandibles of Irradiated Rats

Abstract This study evaluated the action of ionizing radiation and the possible radioprotective effect of the non-steroidal anti-inflammatory drug meloxicam on the bone physiology of rat mandibles by assessing the alveolar socket healing and bone strength. Forty male Wistar rats were divided in 4 groups (n=10): control (CG), irradiated (IG), meloxicam (MG), meloxicam irradiated (MIG). A dose of 0.2 mg/kg meloxicam was administered to MG and MIG. After this, IG and MIG were irradiated with 15 Gy radiation dose in the mandible. Forty days after the above procedures, the mandibular first molars were extracted and the animals were killed after 15 or 30 days (n=5). Micro-computed tomography and bending test were used to evaluate alveolar socket healing and bone strength, respectively. At 15 days, bone volume, bone volume fraction and trabecular thickness were higher in the CG and MG than in the IG and MIG; and trabecular separation was higher in the IG compared with the others. At 30 days, there was a difference only in trabecular separation, which was higher in IG than in CG and MG, and MIG did not differ from the others. Bone strength was lower in IG compared with CG and MG, and MIG did not differ from the others. In conclusion, the ionizing radiation affected the bone physiology of rat mandibles, delaying the alveolar socket healing and reducing the bone strength. Moreover, the meloxicam had a positive effect on the trabecular separation in alveolar socket healing and on the bone strength.

Resumo Este estudo avaliou a ação da radiação ionizante e o possível efeito radioprotetor do anti-inflamatório não esteroide meloxicam na fisiologia óssea de mandíbulas de rato por meio da análise da reparação alveolar e da resistência óssea. Quarenta ratos Wistar machos foram divididos em 4 grupos (n=10): controle (GC), irradiado (GI), meloxicam (GM), meloxicam irradiado (GMI). Administrou-se uma dose única de 0,2 mg/kg de meloxicam no GM e GMI. Posteriormente, o GI e GMI foram irradiados com dose de 15 Gy na região de mandíbula. Decorridos 40 dias dos procedimentos acima, extraiu-se os primeiros molares inferiores dos animais, que foram mortos após 15 e 30 dias (n=5). Utilizou-se a microtomografia computadorizada e o teste de flexão para avaliação da reparação alveolar e da resistência óssea, respectivamente. Aos 15 dias, o volume ósseo, a fração de volume ósseo e a espessura trabecular foram maiores no GC e GM comparados ao GI e GMI; já a separação trabecular foi maior no GI em relação aos demais. Aos 30 dias, houve diferença apenas na separação trabecular, que foi maior no GI em comparação ao GC e GM, não tendo o GMI diferido dos demais. A resistência óssea no GI foi menor em relação ao GC e GM, não tendo o GMI diferido dos demais. Concluiu-se que a radiação ionizante afetou a fisiologia óssea das mandíbulas de rato, promovendo atraso na reparação alveolar e redução da resistência óssea; além disso, o meloxicam, apresentou efeito positivo na separação trabecular da reparação alveolar e na resistência óssea.

Comparison of effects of zoledronic acid and clodronate on the bone structure: imaginological and histomorphometrical study in vivo.

OBJECTIVES: To compare histologically and imaginologically the bone structure of rats' mandibles treated with bisphosphonates (BPs) and rats that did not receive BPs. METHODS: Thirty-four rat specimens (Rattus novergicus, Wistar strain) were divided into three groups: (i) 12 rats treated with zoledronic acid; (ii) 12 rats treated with clodronate; and (iii) the control group, containing 10 rats that received saline solution. All individuals were exposed to cone beam computed tomography (CBCT). The images were processed and analyzed to obtain the Hounsfield scores, using the software OsiriX 7.0. Sixty-eight histological slides were obtained from the specimens and stained with hematoxylin and eosin (HE). Using the software Adobe Photoshop CS6, the histological areas containing non-vital bone were identified and quantified. RESULTS: Non-vital bone presented positive association with the zoledronic acid and clodronate groups. Statistically, no significant difference in bone density was observed among the groups. CONCLUSIONS: Based on the results, the BP therapy alone was sufficient to induce osteonecrosis. In addition, the CBCT was not a sensible method for detection of the early signs of bone modification in individuals under BP therapy.

Micro-CT evaluation of the radioprotective effect of resveratrol on the mandibular incisors of irradiated rats.

The purpose of this study was to perform a microcomputed tomographic evaluation of the radioprotective effect of resveratrol on the volume of mandibular incisors of irradiated rats. A second aim was to make a quantitative assessment of the effect of x-ray exposure on these dental tissues. Twenty adult male rats were divided into four groups: control, irradiated control, resveratrol, and irradiated resveratrol. The resveratrol groups received 100 mg/kg of resveratrol, whereas the irradiated groups were exposed to 15 Gy of irradiation. The animals were sacrificed 30 days after the irradiation procedure, and their mandibles were removed and scanned in a microcomputed tomography unit. The images were loaded into Mimics software to allow segmentation of the mandibular incisor and assessment of its volume. The results were compared by One-way ANOVA and Tukey's post hoc test, considering a 5% significance level. The irradiated groups showed significantly diminished volumes of the evaluated teeth, as compared with the control group (p < 0.05). The resveratrol group presented higher values than those of the irradiated groups, and volumes similar to those of the control group. High radiation doses significantly affected tooth formation, resulting in alterations in the dental structure, and thus lower volumes. Moreover, resveratrol showed no effective radioprotective impact on dental tissues. Future studies are needed to evaluate different concentrations of this substance, in an endeavor to verify its potential as a radioprotector for these dental tissues.

Dental panoramic indices and fractal dimension measurements in osteogenesis imperfecta children under pamidronate treatment.

OBJECTIVES: To verify radiomorphometric indices and fractal dimension (FD) in dental panoramic radiographs (DPRs) of children with different types of osteogenesis imperfecta (OI) and also to verify the effect of pamidronate (PAM) treatment in such panoramic analyses. METHODS: In this retrospective study, 197 DPRs of 62 children with OI Types I, III and IV who were in treatment with a comparable dosage of intravenous PAM were selected. The mandibular cortical width (MCW), mandibular cortical index, visual estimation of the cortical width and FD of three standardized trabecular and cortical mandibular regions of interest were obtained from the radiographs. Factorial analysis of variance and Fisher test were used to compare FD and MCW measurements in children with different types of OI for different PAM cycles. RESULTS: Children with all types of OI have thinner and more porous mandibular cortices at the beginning of treatment. There were significant differences between MCW and FD of the cortical bone, regarding different types of OI and number of PAM cycles (p = 0.037 and p = 0.044, respectively). FD measurements of the trabecular bone were not statistically different among OI types nor were PAM cycles (p > 0.05). CONCLUSIONS: Children with OI presented cortical bone alterations after PAM treatment. Both MCW and the FD of the cortical bone were higher in children with OI after PAM treatment. It is argued that cortical bone should be considered for analyzing patients with OI, as well as to monitor the progress of PAM treatment.