The Gravettian child mandible from El Castillo Cave (Puente Viesgo, Cantabria, Spain).

OBJECTIVES: This article documents an incomplete child's mandible found in H. Obermaier's excavation campaign (in 1912) in El Castillo Cave, Spain. This fossil was assigned to what was then considered a phase of the "Aurignacian-delta". MATERIALS AND METHODS: We exhaustively analyzed the original Obermaier documents, with particular attention to those corresponding to the year of the discovery. We extracted a bone sample to radiocarbon date the fossil directly. We also followed established methods to measure, describe and compare the mandible with other human remains. RESULTS: The analysis of Obermaier's documents and new data derived from modern excavations, show that the mandible was discovered in an interior area of the cave. Direct radiocarbon dating yielded a result of 24,720 ± 210 BP and 29,300 - 28,300 cal BP, a date similar to those known for the Gravettian technocomplex both in the El Castillo site and across Europe. The jaw corresponded to a child aged 4-5 years, with modern morphology, but with a certain robustness, especially in the symphyseal region. Comparisons were made with several modern children (Granada, Spitalfields, and Black series) and with immature fossils (European Aurignacian and Gravettian). The few differences between the modern and the fossil children are related to the symphysis and mandibular corpus thickness and height, and to the symphyseal morphology and larger teeth dimensions. Paleoisotopic data for Castillo C correspond with a varied diet. Numerous cutmarks were identified in the midline internal symphyseal region. DISCUSSION AND CONCLUSIONS: The results agree with those published for other fossils of similar age and chronology (e.g., the mandible of the Lagar Velho child) and show clear differences from the jaws of the young Neanderthals. The interpretation of the original data on the mandible discovery may indicate the destruction of a burial and the displacement, by percolation or by a den, at least of part of the skeleton. The perimortem manipulations in the child's mandible are the first described in the Gravettian world of Western Europe.

Multi-isotope analysis reveals that feasts in the Stonehenge environs and across Wessex drew people and animals from throughout Britain.

The great henge complexes of southern Britain are iconic monuments of the third millennium BCE, representing great feats of engineering and labor mobilization that hosted feasting events on a previously unparalleled scale. The scale of movement and the catchments that the complexes served, however, have thus far eluded understanding. Presenting the largest five-isotope system archeological dataset (87Sr/86Sr, δ34S, δ18O, δ13C, and δ15N) yet fully published, we analyze 131 pigs, the prime feasting animals, from four Late Neolithic (approximately 2800 to 2400 BCE) complexes to explore the networks that the feasts served. Because archeological evidence excludes continental contact, sources are considered only in the context of the British Isles. This analysis reveals wide-ranging origins across Britain, with few pigs raised locally. This finding demonstrates great investment of effort in transporting pigs raised elsewhere over vast distances to supply feasts and evidences the very first phase of pan-British connectivity.

970 nm low-level laser affects bone metabolism in orthodontic tooth movement.

OBJECTIVE: During orthodontic tooth movement (OTM), the speed of movement depends on the rate of bone turnover. In this study, we used a rat model to investigate the effect of 970 nm low-level laser therapy (LLLT) on OTM under different dose and frequency protocols. METHODS: We first compared the OTM rates between the OTM only control and the OTM + LLLT group (1250 J/cm2) in Experiment 1 and showed that LLLT significantly increased OTM. In Experiment 2, we employed 3 different LLLT protocols: the low-dose group and the high-dose group receiving 5 doses of 750 J/cm2 and 15,000 J/cm2 of LLLT every 3 days, respectively, and the early high-dose group which received 5 daily doses at 15,000 J/cm2 at the beginning of the experiments. The OTM-only control group received no LLLT. Tooth movement rate was measured through sequential silicone impressions. MicroCT was also performed to evaluate bone de-mineralization rate. Bone histmorphometry was used to compare the bone turnover rate between LLLT group and control group. Finally, TRAP, Osteocalcin, and VEGF expression is evaluated by immunohistochemistry (IHC) in tissue sections. RESULTS: When LLLT treatment was given every three days, both the 1250 J/cm2 and 15,000 J/cm2 groups showed significantly increased OTM compared to the control group. No significant difference was observed in the 750 J/cm2 group, or in the early irradiation group, when compared with controls, although 750 J/cm2 showed the same trend of accelerating OTM. The MicroCT result of rat maxilla demonstrated that LLLT increased bone remodeling and showed decreased bone mineral density and bone volume/total volume in the furcation areas of the maxillary first molars at the end of experiment. LLLT without OTM increased bone turnover as evidenced by fluorochrome incorporation. Immunohistochemistry analyses revealed high osteocalcin expression at later stages of OTM in the LLLT group, while VEGF expression was highly induced in the LLLT + OTM group at an early stage. CONCLUSION: Our results suggest that the 970 nm LLLT increases the rate of OTM in a dose-sensitive and frequency-dependent manner. Further animal and human studies are needed to determine the optimal timing and dosage of LLLT for OTM acceleration.

Morphological study and mineral analysis of the lower mandible of adult Atlantic salmon (Salmo salar) from Scotland with mandibular deformation / Estudio morfológico y análisis de minerales de la mandíbula inferior de salmones del Atlántico (Salmo salar) adultos con deformación mandibular, provenientes de Escocia

Mandibular deformity is a condition that affects the jaw bone of adult salmon and has been observed in Norway and Chile, causing weight loss, poor quality of farmed fish and increased mortality. The causes range from high temperatures of the state of eggs, to poor nutrition phosphorus or vitamin C. This work aims to analyze this deformity by histochemical and mineral analysis technique during an episode presented in centers of the Scotia Sea. Jaw and spinal segments of 21 Atlantic salmon in Scotland were used. These samples were classified into three groups: Group 1: Severely deformed. Group 2: Mildly affected. Group 3: Normal controls. Four jaws per group were fixed in 10 % formalin and embedded in Paraplast, sections of 5 microns were performed using a Microm® microtome histochemical technique Von Kossa was used for the detection of calcium deposits, which highlights the calcium osteoid black and red color. For proximate analysis, and in order to obtain and compare levels of calcium, phosphorus, zinc and magnesium in total 9 bone jaws (6 affected with DM and 3 controls) and 9 body sections the Mann-Whitney test was used to compare these values between misshapen salmon and controls. To correlate values, jaw and body segment a Spearman corrrelation was applied. Fish group 1 presented a ventral deviation of the alveolar bone body. In fish group 2 prominence of the visible joint on both sides or unilaterally was observed. Comparing the values of % Ca, % P, % Mg and Zn jaws with DM and healthy ones with Mann Witney method it was found that the values of these minerals vary between salmon and controls affected. There was a significant difference in the percentage of P, which indicates that there is less P in affected fish vertebrae. Spearman correlation noted that the percentages of the minerals studied in dental bone and vertebral segments are uncorrelated. Rather, Von Kossa distribution indicates that Ca/P is not homogeneous in the dental bone, as a result of mineral resorption from the skeleton including the operculum, articular bone and dental towards kype. This paper states that Von Kossa histochemical technique showed significant differences between deformed fish and controls and also showed differences between the various segments of the dental bone. The alveolar bone is a dynamic structure adapted to continuous histological changes may be involved in MD, phosphorus deficient diets, coupled with the initial formation of Kippe.

La deformación mandibular es una patología que afecta al hueso dentario de salmones adultos, se observó en Noruega y en Chile, ocasionando disminución de peso, baja calidad de peces cultivados y aumento de la mortalidad. Las causas varían desde temperaturas elevadas al estado de ovas, hasta alimentación deficitaria en fósforo o vitamina C. Este trabajo tiene como propósito analizar esta deformación mediante una técnica histoquímica y de análisis de minerales durante un episodio presentado en centros de mar de Escocia. Se utilizó la mandíbula y segmento vertebral de 21 salmones del Atlántico de Escocia. Estas muestras se clasificaron en tres grupos Grupo 1: Severamente deformes. Grupo 2: Levemente afectados. Grupo 3: Controles normales. Cuatro mandíbulas por grupo fueron fijadas en formalina al 10 % y se incluyeron en paraplast, se realizaron cortes de 5 µm utilizando un micrótomo Microm®. Se utilizó la técnica histoquímica de Von Kossa para la detección de depósitos de calcio la cual destaca al calcio de color negro y el osteoide de color rojo. Para el análisis químico proximal, y con el propósito de obtener y comparar niveles de calcio, fósforo, zinc y magnesio en los huesos se utilizó un total de 9 mandíbulas (6 afectadas con DM y 3 controles) y sus 9 secciones corporales. Para comparar estos valores entre salmones deformes y controles se utilizó la prueba de Mann-Whitney. Para correlacionar los valores de mandíbula y segmento corporal se hizo una correlación por jerarquías de Spearman. Los peces del grupo 1, presentaron una desviación ventral del cuerpo del hueso dentario. En los peces del grupo 2 se observó la prominencia de la articulación visible en ambos lados o unilateralmente. Al comparar los valores de % Ca, % P, % Mg y Zn de las mandíbulas con DM y sanas con el método de Mann Witney se encontró que los valores de estos minerales no varían entre salmones afectados y controles. Hubo una diferencia significativa en el porcentaje de P, lo cual indica que existe menos P en vértebras de peces afectados. La correlación de Spearman señaló que los porcentajes de los minerales estudiados en huesos dentarios y segmentos vertebrales no están correlacionados. Por el contrario, la técnica Von Kossa mostró que la distribución de Ca/ P no es homogénea en el hueso dental producto de la reabsorción mineral desde el esqueleto incluyendo el opérculo, hueso articular y dental hacia la kype. El presente trabajo establece que la técnica histoquímica de Von Kossa fue la que permitió observar diferencias importantes entre peces deformados y controles, además mostró diferencias entre los distintos segmentos del hueso dentario. El hueso dentario es una estructura dinámica adaptada a continuos cambios histológicos pudiendo estar involucrados en la DM, dietas deficientes de fósforo, sumado a la formación inicial del Kippe.

Lidocaine concentration in mandibular bone after subperiosteal infiltration anesthesia decreases with elevation of periosteal flap and irrigation with saline.

It has been reported that the action of infiltration anesthesia on the jawbone is attenuated significantly by elevation of the periosteal flap with saline irrigation in clinical studies; however, the reason is unclear. Therefore, the lidocaine concentration in mandibular bone after subperiosteal infiltration anesthesia was measured under several surgical conditions. The subjects were 48 rabbits. Infiltration anesthesia by 0.5 mL of 2% lidocaine with 1 : 80,000 epinephrine (adrenaline) was injected into the right mandibular angle and left mandibular body, respectively. Under several surgical conditions (presence or absence of periosteal flap, and presence or absence of saline irrigation), both mandibular bone samples were removed at a fixed time after subperiosteal infiltration anesthesia. The lidocaine concentration in each mandibular bone sample was measured by high-performance liquid chromatography. As a result, elevation of the periosteal flap with saline irrigation significantly decreased the lidocaine concentration in the mandibular bone. It is suggested that the anesthetic in the bone was washed out by saline irrigation. Therefore, supplemental conduction and/or general anesthesia should be utilized for long operations that include elevation of the periosteal flap with saline irrigation.

New radiometric ages for the BH-1 hominin from Balanica (Serbia): implications for understanding the role of the Balkans in Middle Pleistocene human evolution.

Newly obtained ages, based on electron spin resonance combined with uranium series isotopic analysis, and infrared/post-infrared luminescence dating, provide a minimum age that lies between 397 and 525 ka for the hominin mandible BH-1 from Mala Balanica cave, Serbia. This confirms it as the easternmost hominin specimen in Europe dated to the Middle Pleistocene. Inferences drawn from the morphology of the mandible BH-1 place it outside currently observed variation of European Homo heidelbergensis. The lack of derived Neandertal traits in BH-1 and its contemporary specimens in Southeast Europe, such as Kocabas, Vasogliano and Ceprano, coupled with Middle Pleistocene synapomorphies, suggests different evolutionary forces acting in the east of the continent where isolation did not play such an important role during glaciations.

ESR and U-series analyses of enamel and dentine fragments of the Banyoles mandible.

The Banyoles mandible presents a puzzle. Its anatomy has been described as pre-Neandertal, but the travertine in which it was found has been dated to 45,000 +/- 4000 years. By this time, any pre-Neandertals had supposedly been absent from the European fossil record for more than 100,000 years. It was therefore proposed that the age of the travertine may represent a minimum age estimate, with the mandible possibly having been reworked from older deposits. We carried out a non-destructive ESR analysis of an enamel fragment removed from a molar and performed a series of in situ laser ablation U-series analyses on dentine fragments adjacent to the enamel piece. The analyses resulted in an apparent combined ESR-U-series age of 66,000 +/- 7000 years. The encasing travertine matrix was also analyzed for U-series isotopes and showed signs of U-mobilization. It cannot be excluded that the travertine matrix is older than the previously determined age. If the mandible was not reworked, then the combined ESR-U-series result on the tooth enamel would give its best age estimate. If, on the other hand, the mandible was reworked from another deposit, the actual ESR-U-series age will depend on the external dose rate from the previous matrix and the depth of its burial, which controls the degree of the attenuation of the cosmic dose rate over time. Considering a range of possible burial histories, the mean age of the mandible would lie somewhere between the combined ESR-U-series age and the previously determined age of the travertine matrix. Regarding the morphology of the mandible, a review of its features in the context of larger Neandertal samples indicates that the anatomy of the specimen is not incompatible with such a young age determination, although it further highlights morphological variation in the late Neandertal sample.

The effect of fluoridation and its discontinuation on fluoride profiles in the alveolar bone of rat.

We investigated the effect of fluoridation and its discontinuation on fluoride content in the alveolar portion of the mandible in rats. Drinking water with three different fluoride contents (0, 50, 100 ppmF) was given to rats for three different periods (4, 13 and 25 weeks). Fluoride concentrations were measured in the crest, the middle, and the apical parts of the alveolar bone and in the body of the mandible. Furthermore, after fluoridated drinking water was given to rats for 4 or 13 weeks, distilled water was given to them for 21 or 12 weeks respectively; and the effect of the discontinuation on fluoride profiles was investigated. Layer samples were analyzed by abrasive microsampling. Fluoride and phosphorus concentrations were determined by ion-specific electrode and colorimetric procedures, respectively. There was an increase in fluoride concentrations in the mandible in proportion to the fluoride content in the drinking water and the duration of fluoridation. After fluoridation was discontinued, fluoride concentrations in the surface layers of the mandible presented a decrease. Among the four different parts of the mandible, the upper part of the alveolar bone and the alveolar crest part presented the highest rates of reduction. The relative reduction rate of fluoride concentration was closely related to the duration of discontinuation. The alveolar crest was affected most by the discontinuation of fluoridation, presenting the greatest reduction.

Effects of erbium,chromium:YSGG laser irradiation on canine mandibular bone.

BACKGROUND: Only relatively few reports have described the morphological effects on bone produced by erbium,chromium: yttrium,scandium,gallium,garnet (Er,Cr:YSGG) laser irradiation, and none has investigated the atomic changes or estimated the temperature increases involved. The objectives of this study were to investigate the morphological, atomic, and temperature changes in irradiated areas during and after laser irradiation, and to evaluate the cutting effect on canine mandibular bone in vitro. METHODS: Two canine mandibular bones were cut into 3 to 5 cm pieces and irradiated by an Er,Cr:YSGG laser utilizing a water-air spray at 5 W and 8 Hz for 10 or 30 seconds. During and after laser irradiation, temperature increases in the irradiated areas were measured by thermography. The samples were then observed by stereoscopy and scanning electron microscopy to determine morphological changes and by energy dispersive x-ray spectroscopy to evaluate atomic alterations. RESULTS: Regular holes or grooves having sharp edges and smooth walls were produced, but no melting or carbonization was observed. The maximum temperature increase was an average 12.6 degrees C for 30-second irradiation. The continuous time of a temperature increase of more than 10 degrees C was consistently less than 10 seconds. An atomic analytical examination revealed that the calcium:phosphorus ratio was not significantly changed between the lased and unlased areas (P>0.0 1). CONCLUSION: These results showed that the Er,Cr:YSGG laser cuts canine mandibular bone effectively without burning, melting, or altering the calcium:phosphorus ratio of the irradiated bone.

[Ultrastructural and Ca/P changes of the regenerated bone after mandibular distraction in goats].

OBJECTIVE: The aim of this study was to examine the ultra structural and the changes of Ca/P elements of the new bone resulting from mandibular distraction osteogenesis. METHODS: Bilateral mandibular osteotomies were performed in six goats. The mandibles in all animals were lengthened 10 mm using a custom made distracter. Each 2 goats were sacrificed respectively at 2, 4 and 8 weeks after completion of distraction. The distracted callus were harvested and processed for SEM evaluation and Ca/P ratio analysis. RESULTS: The newly generated bone in distraction gap was confirmed by SEM examination, and the contents of Ca, P were found to be elevated with the maturity of distracted callus. CONCLUSION: This study suggested that newly formed bone by mandibular distraction osteogenesis in goats could be remodeled to normal bone.

[Bone loss and oral health status in patients on home parenteral nutrition]. / Knogletab og oral status hos patienter i parenteral ernaering i hjemmet.

The mandible and forearm bone mineral content and dental and periodental state were studied in 15 patients, aged 26 to 65 years, on home parenteral nutrition due to short bowel syndrome and compared to the findings in a normal population. The bone mineral content was measured by dual-photon absorptiometry. All patients were on free oral intake as a supplement to the parenteral nutrition. Forty-seven percent of the patients showed mandibular osteoporosis. Thirty-three percent had osteoporosis in the forearm and also radiographic signs of osteoporotic fractures of the columna. The dental and periodental state did not differ from that of the normal Danish population of the same age. Thus, patients on home parenteral nutrition due to short bowel syndrome seem to have a high risk of developing systemic osteoporosis, including the jaws, but apparently do not have a higher risk for deterioration of the dental or periodental state.

Chemical and X-ray analysis of fluoride, phosphorus, and calcium in human foetal blood and hard tissues.

To evaluate the beneficial effect of prenatal fluoride supplementation, the presence of fluoride in hard tissues in two populations of human foetuses coming from fluoridated (> or = 0.7 parts/10(6) F in drinking water) and non-fluoridated areas (< or = 0.1 parts/10(6) F in drinking water) were compared by chemical analysis and X-ray microanalysis. The fluoride concentrations measured in maternal and venous cord blood confirmed that placental transfer of fluoride was passive when fluoride intake was low. Total fluoride contents of tooth germs and mandibular bone appeared to increase with fluoride level in drinking water. However, these concentrations were too low to be detected by X-ray microanalysis. Phosphorus and calcium total contents were identical in mandibular and femoral bone of both populations. In incisor germs, phosphorus and calcium concentrations in enamel and dentine close to the amelodentinal junction did not differ significantly between the two populations. It is suggested that the low fluoride concentrations in enamel and dentine formed in utero would not have a significant effect on acid solubility.

Combined effects of caffeine and alcohol during pregnancy on bones in newborn rats.

The combined effects of caffeine and alcohol on mineral contents of fetal mandibles and femurs were studied. Pregnant rats were divided into four groups: group 1, control; group 2, caffeine; group 3, alcohol; and group 4, caffeine-plus-alcohol. Alcohol (1.0 g ethanol/kg body weight) was intubated twice daily, beginning at day 9 of gestation. Caffeine (2 mg/100 g body weight) was given as a dietary supplement. Groups 1 and 2 were intubated with isocaloric sucrose solution. At birth, randomly selected pups were killed and the mandible and femur were removed and dried. Ca, P, Mg, Zn and hydroxyproline in these bones were measured. Notwithstanding the dams' intake of caffeine and alcohol administered separately, the present results suggest that the combination of caffeine and alcohol exhibited the most detrimental effects.

Evaluation of distraction osteogenesis by scanning electron microscopy.

A model of bifocal distraction osteogenesis in the canine model was used to assess and quantitate the mineral content of the newly forming bone within the canine mandible. A 2-cm defect was created in the body of the mandible, and after a posterior osteotomy, the transport disk was advanced at 0.25 mm per 8 hours for 21 days and then held in rigid fixation for an additional week. As a control for this study, three additional dogs underwent the same procedure with the exception that the transport disk was not advanced. Electron dispersive spectroscopy analysis was performed on the newly formed regenerate bone and compared with areas of existing cortical bone of both the transport disk and the mandible. In the control model, special note was made of the pericortical callus at the osteotomy site as well as of the regenerative bone that filled the 2-cm defect in the body of the mandible. Calcium/phosphorous ratios were used to assess the composition of the mineralized regions of the mandible. The regenerate bone that filled the defect and the mineralized callus surrounding the site of osteoclasis in the control mandible were significantly different in composition when compared with the regenerate bone that formed during distraction osteogenesis. This suggests that distraction osteogenesis may effect an initial matrix production that is more similar in composition to the mature cortical bone from which it was derived than does periosteal regeneration and filling of an osseous defect.

Microscopic and chemical analysis of bone-hydroxyapatite interface in a human retrieved implant. A case report.

The aim of the present study was a histological and chemical analysis of the bone-hydroxyapatite interface in a retrieved human implant. The implant was cut in two: one half was processed for light microscopy with the cutting grinding system, and the other for SEM analysis with EDX and a cathodoluminescence system. Bone maintained an intimate contact with the hydroxyapatite and the bonding of the hydroxyapatite with the metal was very strong. An analysis of the interface from a double staining (basic fuchsin and von Kossa) showed a non-mineralized matrix, interposed between hydroxyapatite and bone in many areas. It is possible that different microscopic features are present in different areas of the interface, however, intimate contact was observed 6 months after insertion of the implant.

Steroid-induced mandibular bone loss in relation to marginal periodontal changes.

Long-term high-dose glucocorticosteroid treatment may be suspected as causing profound marginal periodontal bone loss due to the immunosuppressive/antiinflammatory effects and due to the osteoporotic side-effects. This study comprised an analysis of the loss of the mandibular and forearm bone mineral content (BMC), measured in vivo by dual-photon scanner, in relation to the concomitant changes of the periodontal indices (visible plaque, gingival bleeding, loss of attachment) in 17 acute nephrotic dentate patients undergoing intensive steroid treatment for 12 months. The measurements were performed at start of treatment, when all patients were considered healthy as regards the skeleton, and at the 6-month and 12-month follow-up. The mean BMC loss at the standard sites of the mandible and the forearm bones was 5.6%/year at both sites. No significant changes could be demonstrated in the periodontal indices (P greater than 0.10), and no relation was found between the mandibular BMC loss and the periodontal condition (R = 0.06, P greater than 0.10). In conclusion, profound marginal periodontal bone loss does not seem to be a prominent side-effect of long-term glucocorticosteroid treatment, although the degree of induced osteopenia in the mandible corresponds to that in other cortical bones of the skeleton.

The occurrence of interglobular dentin in incisors of hypophosphatemic mice fed a high-calcium and high-phosphate diet.

The incisor dentin of hypophosphatemic (Hyp) mice was examined histopathologically to determine whether the multiple occurrences of interglobular dentin would be influenced by the serum phosphate level. Both normal and Hyp mice (12 weeks of age) were divided into two groups. The mice in one group were given a control diet (1.42% Ca, 1.16% P) and the other a high-calcium and high-phosphate diet (2.00% Ca, 3.00% P) for 30 days. Blood was collected from the mice every fifth day for measurement of the calcium and phosphate concentrations in serum. Both ground and decalcified cross-sections were prepared from incisors from the mandible and maxilla for microscopic examination. The levels of serum Ca and P were almost constant in normal mice, regardless of diet. On the other hand, serum P levels in Hyp mice fed the control diet were significantly lower than those in normal mice. The ten days' feeding of the high-Ca/-P diet significantly elevated the serum P level in Hyp mice, and it reached a level similar to that of the normal mice. However, histopathological examination showed no significant changes in incisor dentin of Hyp mice fed the high-Ca/-P diet, and interglobular dentin still occurred. These results suggest that the multiple formations of interglobular dentin, which is the most outstanding feature of X-linked hypophosphatemic vitamin-D-resistant rickets, are not influenced in Hyp mice by the short-time normalization of the serum phosphate level.

Comparison of chemical, histomorphometric, and absorptiometric analyses of bones of growing rats subjected to dietary calcium stress.

Absorptiometric, histomorphometric, and chemical analyses of bones from growing rats fed diets with low (0.2%, w/w), marginal (0.4%, w/w), or adequate (0.8%, w/w) calcium (Ca) content with or without phytate were compared. Phytate was added to each diet in a molar ratio of 19:1 to calcium. Male weanling Sprague-Dawley rats were fed one of the six diets for 8 weeks. At the end of 8 weeks, rats were killed, and mandibles, femurs, and tibias were removed. Bone density profiles were determined on the mandibles and femurs using single photon absorptiometry. Femurs were also used for calcium and phosphorus analyses. Tibias were used for histomorphometric analyses. Bone density of the femurs and mandibles increased as dietary Ca increased. The only effect of phytate addition measured was in the 0.8% calcium diet, where density was lower in rats fed the phytate-containing 0.8% calcium diet. Femur calcium concentration also increased as dietary Ca increased and was unaffected by addition of phytate. Femur phosphorus concentration was unaffected by dietary Ca levels but was increased by 10% when phytate was added to the diet. Bone density values were highly correlated with bone calcium and phosphorus levels (r = 0.94). Rats fed the 0.2% calcium diets had 20% lower mineralized bone area and 20% larger medullary cavity area than rats fed the other diets. Bone densitometry appears to be useful for determining changes in bone occurring in growing rats fed low, marginal, and adequate levels of dietary Ca. Bone density values also correlated well with chemically determined calcium and phosphorus concentrations and with histomorphometric data.