Cortical Bone Width Research Articles

Location and Size of Mandibular Canal and Cortical Bone Width in the Second Molar Region

Location and Size of Mandibular Canal and Cortical Bone Width in the Second Molar Region

Mandibular radiomorphometric assessment of bone mineral density in survivors of pediatric hematopoietic stem-cell transplantation

OBJECTIVE:Hematopoietic stem-cell transplantation (HSCT) childhood survivors of hematologic malignancies are prone to develop late osteopenia and osteoporosis. The purpose of this retrospective study was to quantitatively and qualitatively assess bone mineral density (BMD) in HSCT childhood survivors and to compare the effectiveness of both qualitative and quantitative assessment methods.METHODS:DESIGN BMD assessment using panoramic radiographs of childhood HSCT survivors aged 3.69-18.88 years using two radiomorphometric indexes. Case-control double-blinded comparison of panoramic radiographic images from childhood HSCT survivors and age- and sex-matched healthy controls. Quantitative assessment was performed by measuring the cortical bone width bilaterally at the mental foramen level. Qualitative assessment was performed using the mandibular cortical index bilaterally on all panoramic images.RESULTS:Radiographs were taken 6.59-83.95 months after bone marrow transplantation [median±SD=25.92±24.9 months]. Fifty-two panoramic radiographic images were analyzed: 21 from HSCT survivors and 31 from healthy controls aged 3.69-25.1 years [mean±SD=11.89±5.28 years]. The mandibular cortical bone width was 17% smaller in childhood HSCT survivors than in healthy controls (case group: 2.420, control group: 3.307; p=0.00617). Qualitative analysis revealed an increased frequency of severe mandibular cortical erosion in childhood HSCT survivors, although no significant difference was observed (case group: 1.540, control group: 1.490; p=0.32). The interobserver agreement was 85% (Kappa index).CONCLUSIONS:HSCT childhood survivors exhibit quantitative and qualitative mandibular bone impairments. Further studies are needed to establish an association between mandibular cortical bone impairment and osteoporosis.

Comparación de distancias interradiculares y grosor del hueso cortical en dos sectores del maxilar inferior para colocación de mini implantes

Introducción: la colocación de mini implantes interradiculares, como alternativa para el anclaje de aparatología ortodóntica, varía acorde a la clasificación esquelética del paciente Clase I o II. Es necesario realizar la correcta identificación de la ubicación radicular y grosor cortical como parte del análisis estratégico del área a intervenir. Objetivo: comparar tomográficamente las distancias interradiculares y grosor del hueso cortical en dos sectores del maxilar inferior para colocación de mini implantes. Materiales y métodos: estudio transversal que incluyó 120 tomografías computarizadas de haz cónico, pertenecientes a pacientes Clase I (60) y Clase II (60) esquelética. Se identificó tomográficamente la distancia interradicular, el ancho bucolingual y el grosor del hueso cortical bucal, a partir de la cresta alveolar entre el segundo premolar y primer molar inferior derecho y entre el canino y lateral del mismo lado. Un análisis estadístico con prueba t Student al 95% de confianza comparó la ubicación de las estructuras anatómicas para clase I y II esquelética. Resultados: en la distancia interradicular, comparativamente entre clase I y II, se encontró significancia entre canino y lateral derecho (p=< 0.054) a los 8 mm. En este mismo sector, en el ancho bucolingual, se encontró diferencia significativa a 6mm de altura (p=<.04). En el grosor del hueso cortical no se encontraron diferencias estadísticas al comparar los valores para la Clase I y II. Conclusiones: en Clase I y II, el mayor espesor para la colocación de mini implantes se registró en el espacio interradicular a 8 mm de altura y en el ancho bucolingual a 6 mm.

Anatomic assessment of the mandibular buccal shelf for miniscrew insertion in white patients.

Cortical bone thickness, bone width, insertion depth, and proximity to nerves are important factors when planning and placing orthodontic miniscrews. The objective of this study was to anatomically assess the mandibular buccal shelf in a white patient population as the insertion site for orthodontic miniscrews by investigating these 4 variables. Measurements were made on cone-beam computed tomography scans of 30 white patients (18 girls, 12 boys; mean age, 14.5±2years). All measurements were taken adjacent to the distobuccal cusp of the first molar, and the mesiobuccal and distobuccal cusps of the secondmolar. Additionally, bone depth was measured at 2 height levels, 4 and 8mm from the cementoenamel junction. Stereolithographic models of patients were superimposed on the cone-beam computed tomography volumes to virtually create an outline of the soft tissue on the cone-beam computed tomography image to allow identification of the purchase point height (mucogingival junction). The inferior alveolar nerve was digitally traced. Miniscrews (1.6×10mm) were virtually placed at the buccal shelf, and their insertion depths and relationships to the nerve were assessed. Analysis of variance with post hoc analysis was used for data analysis. Insertion sites and measurement levels had significant impacts on both cortical bone thickness and bone width. Cortical bone thickness was typically greatest at the distobuccal cusp of the secondmolar. Bone width was also greatest at the distobuccal cusp of the secondmolar 8mm from the cementoenamel junction. The greatest insertion depth was found again at the distobuccal cusp to the secondmolar, whereas the miniscrews had the greatest proximity to the nerve at this site also. The distobuccal cusp level of the mandibular secondmolar is the most appropriate site for miniscrew insertion at the buccal shelf in white patients.

Mandibular Inferior Cortex Erosion on Dental Panoramic Radiograph as a Sign of Low Bone Mineral Density in Postmenopausal Women.

Objective To examine the role of the panoramic mandibular radiograph in the diagnosis of low bone mineral density (BMD) in postmenopausal women. Methods A cross-sectional study including volunteer women aged over 40 years in amenorrhea due to ovarian failure for at least 12 months, who were cared for at the climacteric outpatient clinic of a university hospital in the city of Cuiabá, in the state of Mato Grosso, Brazil. The panoramic radiographs were evaluated using a specific software. Two aspects were analyzed in the mandibular panoramic radiograph: a qualitative aspect regarding the shape of the mandibular cortical bone, and a quantitative aspect regarding the width of the mandibular cortical bone. The morphology of the mandibular cortical bone in the digital panoramic radiograph was determined bilaterally by the observation of the bone structure between the mental foramen and the base of the jaw. The mandibular cortical bone was categorized into three groups. The mental index (MI) was used to evaluate the thickness of the mandibular cortical bone through a perpendicular line drawn from the base of the mandible at the height of the center of the mental foramen, with another line drawn tangent to the inferior border of the mandible, and a third line parallel to the line at the superior border of the mandible. The MI data are expressed in millimeters, with a normal value of 3.0 mm. The densities of the lumbar spine and femur, expressed in g/cm2, were categorized as normal, osteopenia or osteoporosis. Results The agreement index between the MI and the BMD of the lumbar spine was good (Kappa = 0.718), but the same index between the MI and the BMD of the femoral neck was poor (Kappa = 0.443). An excellent agreement occurred when the mandibular cortical index (MCI) was compared with the BMD of the lumbar spine (Kappa = 0.912). The agreement between MCI and the BMD in the femur was moderated (Kappa = 0.579). Conclusion The radiomorphometric indices evaluated in the mandibular panoramic radiograph are capable of identifying postmenopausal women with low mineral density in the mandible, and the results can be used to refer these women to appropriate medical investigation and/or treatment.

Risk of osteoporosis in elderly individuals attending a dental clinic

Osteoporosis has become a critical public health problem with the rapidly aging population in Japan. It is necessary for dentists to know their patients' status because it influences dental treatment. The purpose of this study was to predict the risk of osteoporosis in elderly patients visiting a dental clinic by assessing mandibular cortical morphology on panoramic radiographs. Three-hundred and thirty patients were divided into three classes based on the morphology of their mandibular cortex on panoramic radiographs. Mandibular cortical bone width at the mental foramen was also measured. Bone mineral density (BMD) was determined at the calcaneus using a quantitative ultrasound device. The mandibular cortical width decreased significantly from Class 1 (normal cortex), to Class 2 (moderately eroded cortex) and to Class 3 (severely eroded cortex). BMD was negatively correlated with age in both female and male patients. Most (108/186) female patients had a class 3 cortex with a low BMD. Among women, mandibular cortical width was significantly correlated with BMD. Thirty-three percent of the female had received a previous diagnosis of osteoporosis. In contrast, only 13.9% (20/144) of the male had a Class 3 cortex. In men, mandibular cortical width did not significantly correlate with BMD. Only a few of the men had received a previous diagnosis of osteoporosis. The number of remaining teeth did not correlate with low BMD in either sex. Our findings reveal that most elderly female patients visiting the dental clinic had a high risk of osteoporosis and a low BMD.

Cortical bone deficit and fat infiltration of bone marrow and skeletal muscle in ambulatory children with mild spastic cerebral palsy

IntroductionNonambulatory children with severe cerebral palsy (CP) have underdeveloped bone architecture, low bone strength and a high degree of fat infiltration in the lower extremity musculature. The present study aims to determine if such a profile exists in ambulatory children with mild CP and if excess fat infiltration extends into the bone marrow. Materials and methodsAmbulatory children with mild spastic CP and typically developing children (4 to 11years; 12/group) were compared. Magnetic resonance imaging was used to estimate cortical bone, bone marrow and total bone volume and width, bone strength [i.e., section modulus (Z) and polar moment of inertia (J)], and bone marrow fat concentration in the midtibia, and muscle volume, intermuscular, subfascial, and subcutaneous adipose tissue (AT) volume and intramuscular fat concentration in the midleg. Accelerometer-based activity monitors worn on the ankle were used to assess physical activity. ResultsThere were no group differences in age, height, body mass, body mass percentile, BMI, BMI percentile or tibia length, but children with CP had lower height percentile (19th vs. 50th percentile) and total physical activity counts (44%) than controls (both p<0.05). Children with CP also had lower cortical bone volume (30%), cortical bone width in the posterior (16%) and medial (32%) portions of the shaft, total bone width in the medial-lateral direction (15%), Z in the medial-lateral direction (34%), J (39%) and muscle volume (39%), and higher bone marrow fat concentration (82.1±1.8% vs. 80.5±1.9%), subfascial AT volume (3.3 fold) and intramuscular fat concentration (25.0±8.0% vs. 16.1±3.3%) than controls (all p<0.05). When tibia length was statistically controlled, all group differences in bone architecture, bone strength, muscle volume and fat infiltration estimates, except posterior cortical bone width, were still present (all p<0.05). Furthermore, a higher intermuscular AT volume in children with CP compared to controls emerged (p<0.05). ConclusionsAmbulatory children with mild spastic CP exhibit an underdeveloped bone architecture and low bone strength in the midtibia and a greater infiltration of fat in the bone marrow and surrounding musculature compared to typically developing children. Whether the deficit in the musculoskeletal system of children with CP is associated with higher chronic disease risk and whether the deficit can be mitigated requires further investigation.

Metacarpal Cortical Bone Area Predicts Tooth Loss in Men.

The relationship between bone mineral density and tooth loss in men is unclear. The aim of this retrospective cohort study was to determine if relative metacarpal bone area (MCA) predicts tooth loss in a cohort of 273 male participants in the Dental Longitudinal Study and Normative Aging Study of the Department of Veterans Affairs. Outer and inner cortical bone widths of the middle metacarpal of the nondominant hand were measured on anteroposterior hand radiographs approximately 11 y apart. Baseline MCA was computed and categorized into quartiles. The men were followed from 1971 to 2015. Incident tooth loss during 2 intervals was examined: concurrent with the MCA measurements and long term over the total follow-up (17 ± 7 y). Radiographic alveolar bone loss (ABL) was measured on periapical radiographs as a percentage of the distance from the cementoenamel junction to root apex, and the number of teeth with ABL >40% was computed. Negative binomial generalized linear regression models estimated the mean number of teeth with ABL >40% and the number lost (concurrent and total), controlling for age, smoking, number of teeth at baseline, percentage teeth with ≥1 decayed/filled surface, and years of follow-up. At baseline, MCA was inversely related to number of teeth with >40% ABL. Men in the lowest MCA quartile (Q1) lost the most teeth, both concurrent with MCA measurements and long term, but the association differed by caries level (≤55% or >55% decayed/filled teeth). At the low caries level, the numbers lost in Q1 were 29% greater than in the highest MCA quartile (Q4). At the high caries level, the numbers lost in Q1 were more than twice those in Q4. Associations were attenuated when further controlled for number of teeth with ABL>40%. These findings suggest that systemic bone status plays a role in tooth loss and that the association may be mediated by alveolar bone loss. Knowledge Transfer Statement: Low relative metacarpal bone area was related to loss of alveolar bone and incident tooth loss in men. This information extends previous research, primarily studies of women, showing that osteoporosis adversely affects oral health. Knowledge of a patient's systemic bone status may be important for managing his or her periodontal disease. Tooth loss in the absence of periodontal inflammation may signify systemic bone loss. Interprofessional communication is central to maintaining optimal oral and bone health.

Content Validity of Temporal Bone Models Printed Via Inexpensive Methods and Materials.

Computed tomographic (CT) scans of the 3-D printed temporal bone models will be within 15% accuracy of the CT scans of the cadaveric temporal bones. Previous studies have evaluated the face validity of 3-D-printed temporal bone models designed to train otolaryngology residents. The purpose of the study was to determine the content validity of temporal bone models printed using inexpensive printers and materials. Four cadaveric temporal bones were randomly selected and clinical temporal bone CT scans were obtained. Models were generated using previously described methods in acrylonitrile butadiene styrene (ABS) plastic using the Makerbot Replicator 2× and Hyrel printers. Models were radiographically scanned using the same protocol as the cadaveric bones. Four images from each cadaveric CT series and four corresponding images from the model CT series were selected, and voxel values were normalized to black or white. Scan slices were compared using PixelDiff software. Gross anatomic structures were evaluated in the model scans by four board certified otolaryngologists on a 4-point scale. Mean pixel difference between the cadaver and model scans was 14.25 ± 2.30% at the four selected CT slices. Mean cortical bone width difference and mean external auditory canal width difference were 0.58 ± 0.66 mm and 0.55 ± 0.46 mm, respectively. Expert raters felt the mastoid air cells were well represented (2.5 ± 0.5), while middle ear and otic capsule structures were not accurately rendered (all averaged <1.8). These results suggest that these models would be sufficient adjuncts to cadaver temporal bones for training residents in cortical mastoidectomies, but less effective for middle ear procedures.

Magnetization transfer imaging of cortical bone in vivo using a zero echo time sequence in mice at 4.7T: a feasibility study.

To investigate the feasibility of magnetization transfer (MT) imaging in mice in vivo for the assessment of cortical bone. MT-zero echo time data were acquired at 4.7T in six mice using MT preparation pulses with two different flip angles (FAs) and a series of ten different off-resonance frequencies (500-15000Hz). Regions of interest were drawn at multiple levels of the femoral cortical bone. The MT ratio (MTR) was computed for each combination of FAs and off-resonance frequencies. T1 measurements were used to estimate the direct saturation (DS) using a Bloch equation simulation. Estimation of the absorption line width of cortical bone from T2* measurements was also performed. MTR values were higher using 3000° FA than 1000° FA. MTR values decreased toward higher off-resonance frequencies. Maximum mean MTR±standard deviation (SD) of 58.57±5.22 (range 50.44-70.61) was measured with a preparation pulse of 3000° and off-resonance frequency of 500Hz. Maximum "true" MT effect was estimated at around 2-3 and 5kHz, respectively, for 1000° and 3000° FA. Mean full width at half maximum ± SD of 577±91Hz was calculated for the absorption spectral line of the cortical bone. MT imaging can be used for the assessment of cortical bone in mice in vivo. DS effects are negligible using preparation pulses with off-resonance frequencies greater than 3kHz.

Computed tomographic assessment of early changes of the mandible in bisphosphonate-treated patients

To compare the computed tomography (CT) features of mandibular cancellous and cortical bones between patients with bisphosphonate (BP) administration and those without and to assess the early changes of the mandible in BP-treated patients. Twenty-four BP-treated patients suffering from medication-related osteonecrosis of the jaw (MRONJ) were enrolled in this study. For comparison, 20 patients suffering from osteomyelitis and 20 patients without pathology in the jaw were also enrolled, all of whom did not receive BP treatment. The CT values of the cancellous and cortical bone and the cortical bone widths were measured. In the MRONJ and osteomyelitis groups, there were significant differences in the CT values of cancellous and cortical bones between the affected and unaffected areas. In patients with stage 0 MRONJ, a significant difference was noted in the cancellous bone CT values between these areas. The cancellous bone CT values at the affected and unaffected areas in the BP-treated group were significantly higher than in the control groups. In patients with stage 0 MRONJ, the cancellous bone CT values at the affected area were also significantly higher than in the healthy patients. The cortical bone widths in the unaffected areas in the BP-treated patients were significantly larger than in healthy patients. The cancellous bone CT values were higher in the BP-treated group, including in patients with stage 0 MRONJ, and CT may provide useful quantitative information.

CORTICAL BONE SEGMENTATION USING WATERSHED AND REGION MERGING BASED ON STATISTICAL FEATURES

Research on biomedical image is a subject that attracted many researchers’ interest. This is because the biomedical image could contain important information to help analyze a disease. One of the existing researches in his field uses dental panoramic radiographs image to detect osteoporosis. The analyzed area is the width of cortical bone. To analyze that area, however, we need to determine the width of the cortical bone. This requires proper segmentation on the dental panoramic radiographs image. This study proposed the integration of watershed and region merging method based on statistical features for cortical bone segmentation on dental panoramic radiographs. Watershed segmentation process was performed using gradient magnitude value from the input image. The watershed image that still has excess segmentation could be solved by region merging based on statistical features. Statistical features used in this study are mean, standard deviation, and variance. The similarity of adjacent regions is measured using weighted Euclidean distance from the statistical feature of the regions. Merging process was executed by incorporating the background regions as many as possible, while keeping the object regions from being merged. The segmentation result has succeeded in forming the contours of the cortical bone. The average value of accuracy is 93.211%, while the average value of sensitivity and specificity is 93.858% and respectively.

Cardiovascular and bone health of former elite infantry soldiers at middle life.

BackgroundThe long term implications of elite infantry service on cardiovascular health and cortical bone width at middle age has not been studied. The purpose of this study was to compare the cardiovascular health and cortical bone thickness of former elite infantry soldiers at middle life with a sedentary population of religious scholars using seven factors associated with cardiovascular risk and QCT tibial cross sections 8 cm above the ankle joint.ResultsTorah scholars had a higher 5 year risk for a fatal or non fatal cardiovascular event (p = 0.008) than former elite infantry soldiers. The former elite infantry soldiers had wider tibia cortices than Torah scholar (p = 0.003).ConclusionsThis study shows that former elite infantry soldiers who performed strenuous physical activity during their military service and continued physical activity in their subsequent life, had stronger tibias based on increased cortical width and a modest decrease in cardiovascular risk at middle life compared to sedentary Torah scholars.

Retracted: New bone formation in bone defects after melatonin and porcine bone grafts: experimental study in rabbits

The aim of this study was to evaluate the effect of the topical application of melatonin compared with collagenized porcine bone grafts to accelerate bone formation 2 months after their insertion in tibiae rabbits. Twenty New Zealand rabbits weighing 3,900-4,500 g were used. Twenty collagenized porcine bone (MP3) grafts, twenty melatonin-impregnated bone grafts, and twenty control areas were placed in the proximal metaphyseal area of both rear tibias. Four groups were formed according to the moment in which animal killing was carried out: Group I (15 days), Group II (30 days), Group III (45 days) and Group IV (60 days). Cortical width and cortical length of bone formation was measured. Following implantation, an anteroposterior and lateral radiological study was carried out. Samples were sectioned at 5 μm and stained using hematoxylin-Eeosin, Masson's trichromic, and Gordon-Switt reticulin stains. After 60 days of treatment period, melatonin increased the length of cortical bone formation 99.03 ± 0.61% like control 98.90 ± 3.82% compared with porcine bone 92.73 ± 1.08%. Related to perimeter of cortical bone of the tibiae melatonin new bone was 98.35 ± 1.14% like control 98.0 ± 1.43% more than porcine bone 92.05 ± 1.03%. Histomorphometric values related to porcine bone were connective tissue 49.16 ± 2.4%, graft material (MP3) 23.52 ± 2.3%, and new bone formation 27.32 ± 1.4% compared with test group with melatonin 24.5 ± 1.2%, connective tissue 45.1 ± 1.2%, and new bone formation of 30.4 ± 1.0%. Melatonin has proven to regenerate the width and length of cortical bone in tibiae rabbits more quickly than collagenized porcine bone. Melatonin acts as a bone stimulator compared with porcine bone and control sites.

A simple evaluation method for early detection of bisphosphonate-related osteonecrosis of the mandible using computed tomography

ObjectivesThe aim of this study was to establish a simple method for the early detection of bisphosphonate-related osteonecrosis of the jaw (BRONJ) using computed tomography (CT). Materials and methodsCT images of the mandible were obtained from a total of 20 patients with BRONJ and 20 control subjects. BRONJ was classified into 2 groups, with bone exposure (Stage 1–3 BRONJ) or without (Stage 0 BRONJ). In each patient, 15 transaxial CT images were selected and 30 configured regions of interest (ROI) were identified. The ANOVA test was applied to test the relationship between the severity of systemic risk factors. ResultsRegarding the local status of the mandible, significant differences were observed among the Stage 0 BRONJ, Stage 1–3 BRONJ, non-BRONJ and control groups in the cancellous bone CT radiodensity values, but there were no significant differences between the Stage 0 and Stage 1–3 BRONJ groups. In the cortical bone widths, significant differences were observed only between BRONJ and the controls. ConclusionsMeasuring cancellous bone CT radiodensity value has the potential to be a simple and quantitative method to detect the early stages of BRONJ.

Fractal dimension and mandibular cortical width in normal and osteoporotic men and women

ObjectiveTo verify whether fractal dimensions (FD) on the mandibular trabecular and cortical bone and mandibular cortical width (MCW) differ between patients with normal bone mineral density (BMD) and osteoporosis. Study designIn this retrospective study, 133 dental panoramic radiographs from men aged >60 years and postmenopausal women with a bone densitometry report of the lumbar spine and hip classified as either normal or osteoporotic were selected. Fractal dimensions of five standardized trabecular and cortical mandibular regions of interest and mandibular cortical width were measured on the panoramic radiographs by an experienced oral radiologist, blinded to the densitometric diagnosis. The following statistical analyses were performed: ANOVA and a forward logistic stepwise regression to verify associations between dental panoramic measurements and the densitometric diagnosis. P values less than .05 indicated statistical significance. Main outcome measuresFractal dimension and mandibular cortical width. ResultsDifferences were found in the FD values on mandibular cortical bone and MCW between patients with normal BMD and with osteoporosis, but not in the FD values of trabecular bone. The odds of having lower mean values of MCW and FD on cortical bone were 2.16, 3125 and 1005 times in osteoporotic patients, respectively, compared with patients with normal BMD. ConclusionThe values of FD analysis on mandibular cortical bone and MCW were lower in women with osteoporosis. A well-adjusted logistic regression model showed that cortical bone measurements might be considered as auxiliary tools to referring patients for DXA exam.

Effects of different doses of soy isoflavones on bone tissue of ovariectomized rats

Aim Studies report that hormone replacement prevents osteoporosis, but there are doubts whether isoflavones are really efficient in this process. The aim of this study was to evaluate the effects of different doses of soy isoflavones on bone tissue of ovariectomized rats.Methods Forty female rats at the age of 6 months were ovariectomized and, after 3 months, the animals were divided into four groups: GI – Control (treated with drug vehicle); GII – treated with isoflavones (80 mg/kg per day); GIII – treated with isoflavones (200 mg/kg per day) and GIV – treated with isoflavones (350 mg/kg per day). Soy isoflavones were administered by gavage for 90 consecutive days. After treatment, the rats were euthanized and their distal femurs were removed for histological routine, histochemistry and biochemical study. Histological sections were stained with hematoxylin–eosin or subjected to picrosirius red and alcian blue methods. Shafts of femurs were submitted to biochemical assay and tibias were subjected to biophysical and biomechanical tests.Results In distal femurs, the trabecular bone volume was higher in the groups treated with isoflavones, being higher in GIV, while the cortical bone width and the presence of mature type I collagen fibers were higher in GII. At the trabecular bone region, the percentage of total glycosaminoglycans (GAGs) was higher in GII and the percentage of only sulfated GAGs was higher in GIII, while the higher content of chondroitin sulfate in shafts of femurs was seen in GIV. Biophysical and biomechanical tests in tibias did not differ among the groups.Conclusion Our data indicate that soy isoflavones improve bone quality in femurs of rats by increasing histomorphometric parameters, the content of GAGs and mature type I collagen fibers. These positive effects are dose-dependent and it was different in cortical and trabecular bone.

Histomorphometric analysis of bone deposition at Ti implant surface dip-coated with hydroxyapatite (In vivo study)

Background: Synthetic hydroxyapatite,(Ca10(PO4)6(OH2) can directly bond to bones without infection and fibrous encapsulation, thus is regarded as bioactive and biocompatible. The aim of the study was the estimation of microarchitecture bone parameters include bone mass (gm/cm2) cortical bone width (mm), thread width (mm), marrow space star volume analysis (V*m) and osteoblast, osteocyte cell number. Materials and methods: Ninety-six (96) commercially pure titanium CpTi) used in this study, (48) implants were coated with HA by dipping coating and (48) implants were used as control. They were inserted in (32) Newzland white rabbits and followed for 2 & 6 weeks. Mechanical torque removal test and histomorphometric analysis of bone microarchiteture were performed for evaluation of osseointegration. Results: Results revealed, Torque values were increased with advancing time for coated and uncoated groups. And specifically dip coated implant showed high value in comparison to control. Histomorphometric analysis for bone parameters showed highly significant difference in overall contrasted groups of implant in 2nd and 6th week interval. Conclusion: Dip coating method is an alternative coating technique for dental implant to enhance better bone implant contact and improve osseointegration.

Effects of soy isoflavones and mechanical vibration on rat bone tissue

Objective To investigate the effects of soy isoflavones (Iso) and mechanical vibration treatments alone or combined on bone extracellular matrix constituents of ovariectomized rats.Methods Forty female Wistar rats at the age of 6 months were ovariectomized (Ovx) and ten were sham-operated (sham). After 3 months, the animals were divided into five groups: GI (sham); GII (Ovx); GIII, ovariectomized and orally treated with isoflavones (200 mg/kg) for 90 consecutive days; GIV, ovariectomized and submitted to vibration for 90 days (5 days/week); GV, ovariectomized and treated with isoflavones plus vibration. After treatments, the rats were euthanized, and their femurs were removed for histological routine and biochemical study. Histological sections were stained with hematoxylin–eosin, picrosirius red and alcian blue. Shaft of femurs were submitted to biochemical assay and tibias were subjected to biophysical and biomechanical tests.Results Treatments did not have significant effects on the trabecular bone volume, but the combined treatments showed trophic effects on the cortical bone width and area. Bone density and the content of organic material of the tibias were higher in the GIV and GV groups. The GV group showed the highest presence of mature collagen fibers and content of total glycosaminoglycans, while the highest contents of chondroitin sulfate and other sulfated glycosaminoglycans were seen in the GIV group.Conclusion The mechanical vibration treatment is more efficient than soy isoflavones in improving bone quality by increasing the bone density, the content of sulfated glycosaminoglycans and the presence of mature collagen fibers. In addition, the combined interventions have partial trophic and synergistic effects that are bone site-specific in ovariectomized rats.

Correlation of mandibular impacted tooth and bone morphology determined by cone beam computed topography on a premise of third molar operation

To determine the width and morphology of the mandible in the impacted third molar region, and to identify the location of the mandibular canal prior to planning impacted third molar operations. Cone beam computed tomography (CBCT) data of 87 mandibular third molars from 62 Japanese patients were analyzed in this study. The width of the lingual cortical bone and apex-canal distance were measured from cross-sectional images in which the cortical bone was thinnest at the lingual side in the third molar region. Images were used for measuring the space (distance between the inner border of the lingual cortical bone and outer surface of the third molar root), apex-canal distance (distance from the root of the third molar tooth to the superior border of the inferior alveolar canal) and the cortical bone (width between the inner and outer borders of the lingual cortical bone). The means of the space, apex-canal distance and lingual cortical width were 0.31, 1.99, and 0.68mm, respectively. Impacted third molar teeth (types A-C) were observed at the following frequencies: type A (angular) 37%; type B (horizontal), 42%; type C (vertical), 21%. The morphology of the mandible at the third molar region (types D-F) was observed as: type D (round), 49%; type E (lingual extended), 18%; and type F (lingual concave), 32%. The width and morphology of the mandible with impacted teeth and the location of the mandibular canal at the third molar region could be clearly determined using cross-sectional CBCT images.