颌骨骨折后血清无机盐及碱性磷酸酶的变化及意义

目的 研究颌骨骨折后血清无机盐和碱性磷酸酶（ALP）的变化和意义。方法 对40例例颌骨骨折患者和14例健康人进行血清钠、钾、氯、钙、磷、镁以及ALP含量的测定并作配对比较。结果 颌骨骨折组钠、钾、氯、钙含量与对照组无明显差异,磷、镁、ALP含量明显高于对照组（P＜0．05）。颌骨多线粉碎性骨折组的钙、磷、镁、ALP高于颌骨单、双线型骨折组,其中钙无明显差异,磷、镁、ALP有明显差异（P＜0．05）。单纯骨折组钙、磷、镁、ALP均低于骨折合并全身损伤组（P＞0．05）。骨折后即刻钙、磷、镁、ALP均高于骨折后4周,其中钙、磷无明显差异,镁、ALP有显著差异（P＜0．05）。结论 颌骨骨折后血清无机盐和ALP含量增高,它可能颌骨骨折的愈合与成骨过程中起着重要的调节作用。     

Secondary ion mass spectrometry and X-ray microanalysis of hypomineralized enamel in human permanent first molars

A common finding in Swedish children is hypomineralization in first molars of unknown cause. Little is known about the chemical composition of the disturbed enamel. The aim here was to analyse the concentration gradients for F, Cl, Na, Mg, K and Sr in hypomineralized enamel from 17 permanent molars by means of secondary ion mass spectrometry, to complete this analysis with an examination of the main matrix elements O, P and Ca by means of X-ray microanalysis, and to compare them with normal enamel. Hypomineralized enamel had a higher content of carbon and the calcium as well as the phosphorus concentration was lower than in normal enamel. The mean Ca/P ratio in hypomineralized areas was significantly lower (1.4) than in the adjacent normal enamel (1.8). The F content was highly variable in impaired enamel and higher than in normal, but close to the surface there was most often no difference between the two. Contents of Mg and K were slightly higher in hypomineralized areas, especially towards the surface. Also Na had a somewhat higher content toward the surface in defective enamel. Cl and Sr contents had negligible or no diversity in relation to the degree of mineralization.     

Effects of a high sucrose diet and intragastric sucrose feeding on the dentinogenesis, dental caries, and mineral excretion of the young rat

Previous studies show that a high sucrose diet reduces the rate of primary dentinogenesis and increases dental caries, although their cause-effect relationship is still obscure. The purpose of this study was to explore whether the effect of sucrose load on the dentinogenesis and dental caries of young rat molars is mediated by systemic (intragastric) or by systemic and local (dietary) factors. At weaning (19 days), animals were randomized into the control, intragastric sucrose, and dietary sucrose groups for 4 weeks. The areas of dentin appositions and dentinal caries lesions were measured planimetrically. Caries was also determined with Shiffs staining and the width of predentin by histology. Urinary Ca, K, and Na levels were measured by flame photometry, urinary P levels using an UV method, and serum insulin levels using radioimmunoassay. Systemic and local sucrose load reduced dentin appositions and intragastric sucrose increased urinary Ca excretion. No differences in the width of predentin were noticed. Only dietary sucrose enhanced the occurrence and progression of caries. The present findings show that sucrose load reduces dentinogenesis by impairing the synthesis of dentin matrix, but also point out the crucial importance of the local sucrose challenge in the initiation of dental caries.     

Effects of a high sucrose diet and intragastric sucrose feeding on the dentinogenesis,dental caries,and mineral excretion of the young rat

Previous studies show that a high sucrose diet reduces the rate of primary dentinogenesis and increases dental caries, although their cause-effect relationship is still obscure. The purpose of this study was to explore whether the effect of sucrose load on the dentinogenesis and dental caries of young rat molars is mediated by systemic (intragastric) or by systemic and local (dietary) factors. At weaning (19 days), animals were randomized into the control, intragastric sucrose, and dietary sucrose groups for 4 weeks. The areas of dentin appositions and dentinal caries lesions were measured planimetrically. Caries was also determined with Shiff's staining and the width of predentin by histology. Urinary Ca, K, and Na levels were measured by flame photometry, urinary P levels using an UV method, and serum insulin levels using radioimmunoassay. Systemic and local sucrose load reduced dentin appositions and intragastric sucrose increased urinary Ca excretion. No differences in the width of predentin were noticed. Only dietary sucrose enhanced the occurrence and progression of caries. The present findings show that sucrose load reduces dentinogenesis by impairing the synthesis of dentin matrix, but also point out the crucial importance of the local sucrose challenge in the initiation of dental caries.     

Dissolution and precipitation reactions in human tooth enamel under weak acid conditions

Slices of enamel were demineralized in weak acid solutions at pH 5. The solutions were analysed for Ca, P, Na and Mg. A substantial increase of the Ca/P ratio in the solution after about 6 h of demineralization was ascribed to brushite formation. The ratios of liberated Ca/Na, P/Na, Ca/Mg and P/Mg were always lower than the correspondent ratios in sound enamel. It was concluded that precipitation of brushite, and a preferential dissolution of Na and Mg compounds from the enamel both play a role in the dissolution-precipitation reactions in dental enamel during acid attack.     

Immunohistochemical study of chondroitin sulfate and dermatan sulfate proteoglycan in dental pulp and dentin

We investigated the localization of chondroitin sulfate and dermatan sulfate proteoglycans in the dental pulp and dentin of rats, using a combination of an immunohistochemical technique coupled with specific enzymatic digestion. Chondroitin 4-sulfate and dermatan sulfate were found to be widespread in pulpal connective tissue, predentin and dentinal tubules. The response to predentin was found to be particularly strong. Chondroitin 6-sulfate was stretched in pulpal connective tissue and predentin, but showed only a weak response.     

钙结合蛋白Calbindin-D28K在人健康和龋坏牙齿中免疫定位

目的：探讨Ｃａｌｂｉｎｄｉｎ－Ｄ２８Ｋ（ＣａＢ）在牙髓损伤修复过程中的作用。方法：用免疫组化ＡＢＣ法观察ＣａＢ在健康和龋坏人恒牙牙髓中的表达,并用图像分析系统进行半定量分析。结果：ＣａＢ在正常和龋病牙髓中成牙本质细胞、前期牙本质、血管内皮细胞及神经纤维中均有表达。在中龋和龋组部分牙髓细胞ＣａＢ弱阳性表达。中龋组成牙本质细胞数目增多,胞浆、胞突及部分胞核强阳性。龋组前期牙本质层变薄,成牙本质细胞空泡     

The role of sensory neuropeptides and nitric oxide on pulpal blood flow and tissue pressure in the ferret.

A study was designed to investigate the effects of close intra-arterial infusion of antagonists to the sensory neuropeptides calcitonin gene-related peptide and substance P, as well as the effect of the nitric oxide synthesis inhibitor L-NAME on pulpal blood flow and interstitial fluid pressure during resting conditions and after electrical tooth stimulation. The micropuncture technique was used to measure tissue pressure and laser-Doppler flowmetry for blood flow recordings in ferret canine teeth. Close intra-arterial infusion of antagonists to calcitonin gene-related peptide and substance P significantly reduced resting blood flow (p < 0.05) and interstitial fluid pressure (p < 0.005) by unchanged systemic arterial pressure, while L-NAME administration caused a significant rise in interstitial fluid pressure (p < 0.05) and systemic arterial pressure (p < 0.005), with a concomitant fall in resting blood flow (p < 0.005). Tooth stimulation after calcitonin gene-related peptide antagonist infusion gave no significant change in blood flow or interstitial fluid pressure, whereas substance P antagonist infusion only partly eliminated the vasodilator response. L-NAME had no effect on the vasodilation induced by tooth stimulation. It is concluded that a resting vasodilator tone due to release of calcitonin gene-related peptide, substance P, and nitric oxide exists in the ferret dental pulp. The sensory neuropeptides exert their effect predominantly on pre-capillary vessels, and nitric oxide predominantly on post-capillary vessels. The sensory neuropeptide calcitonin gene-related peptide seems to be mainly responsible for the increase in blood flow and interstitial fluid pressure during tooth stimulation, whereas there was no evidence that nitric oxide participates in the vasodilation induced by tooth stimulation.     

牙源性颌骨囊肿患者血清钙、磷、镁及ALP变化的临床意义

目的 :研究血清钙、磷、镁及ALP在牙源性颌骨囊肿患者中的变化及其作用。方法 :对 138例颌骨囊肿患者进行血清钙、磷、镁及ALP含量的测定与分析。结果 :颌骨囊肿组的钠、钾、氯、钙含量与正常对照组无明显差异 (p >0.05 )。磷、镁、ALP含量明显高于对照组 (p <0.05)。发育性与炎症性颌骨囊肿患者的磷、镁、ALP无明显差异 (p >0.05)。直径大于 5cm的颌骨囊肿或手术后颌骨囊肿患者的磷、镁、ALP明显高于小于 5cm或手术前颌骨囊肿患者的含量 (p <0.05)。结论 :牙源性颌骨囊肿患者的磷、镁、ALP含量是相对增高的 ,它受囊肿的大小、手术的刺激而变化 ,它们在颌骨囊肿破骨与成骨之间起主要的调节作用。     

Scanning electron microscope observations on collagen fibers in human dentin and pulp.

Human permanent teeth were examined in the scanning electron microscope after demineralization and exposure to preparative procedures based on hydrogen peroxide, trypsin, and EDTA. These substances removed the inorganic material, the cellular structures, the homogeneous connective tissue ground substance, and interfibrillar matrix. The remaining tissue components comprised a network of distinct collagen fibers whose organization was related to the type of tissue in which these were incorporated. A similar or identical method has not been developed or applied to teeth previously. Dentin and predentin comprised a compact mass of fibers which basically were parallel to the continuously growing interior surface of the predentin, or arranged at an acute angle to this plane. Collagen fibers in the pulp were numerous, but lacked any particular orientation in most areas. Interodontoblastic fibers crossed the odontoblastic zone at a right angle to the pulp chamber wall and mingled with collagen fibers in predentin. When previously published findings of ours are taken into account, it is possible to conclude that other factors than the organization of the collagen fibers are responsible for the stainability of these fibers in predentin and in interglobular dentin with silver methenamine, and that aldehyde groups on collagen fibers in predentin may be actively and directly involved in the mineralization of the dentin.     

Mineral composition of enamel and dentin of primary and permanent teeth in Finland

abstract – The concentrations of 12 different elements were measured in dentin and enamel of primary and permanent teeth collected in six different localities in Finland. Na, Cl, Al, Mn, Ca, and P were determined by neutron activation analysis, K, Mg, Zn, Cu, and Fe by the atomic absorption method, and F with the fluoride-specific electrode. Most elements were present in higher concentrations in the enamel than in the dentin: Mg, however, was higher in the dentin. Compared with the permanent teeth, the primary teeth contained more K and Mn in enamel and K and Mg in dentin, but less Na and Zn in enamel. Differences between the six localities were significant for F, Cl, K, Zn, Na, and Mn. Fe, Cu, and Mn contents of teeth were much lower in Finland than elsewhere; in the typical Finnish diet the contents of Fe and Cu are relatively low and iron deficiency anemia is unusually common in Finland.     

Scanning electron microscope observations on collagen fibers in human dentin and pulp

Abstract – Human permanent teeth were examined in the scanning electron microscope after demineralization and exposure to preparative procedures based on hydrogen peroxide, trypsin, and EDTA. These substances removed the inorganic material, the cellular structures, the homogeneous connective tissue ground substance, and interfibrillar matrix. The remaining tissue components comprised a network of distinct collagen fibers whose organization was related to the type of tissue in which these were incorporated. A similar or identical method has not been developed or applied to teeth previously. Dentin and predentin comprised a compact mass of fibers which basically were parallel to the continuously growing interior surface of the predentin, or arranged at an acute angle to this plane. Collagen fibers in the pulp were numerous, but lacked any particular orientation in most areas. Interodontoblastic fibers crossed the odontoblastic zone at a right angle to the pulp chamber wall and mingled with collagen fibers in predentin. When previously published findings of ours are taken into account, it is possible to conclude that other factors than the organization of the collagen fibers are responsible for the stainability of these fibers in predentin and in interglobular dentin with silver methenamine, and that aldehyde groups on collagen fibers in predentin may be actively and directly involved in the mineralization of the dentin.     

Distributions of magnesium and sulphur in defect layers of incisor dentine in magnesium-deficient rats

This study examined the mechanism governing the occurrence of defect layers of incisor dentine in Mg-deficient rats by X-ray microanalysis. Young (5 weeks of age) Wistar male rats were pair-fed semi-synthetic diets containing either control (0.05% Mg) (N = 8) or Mg-deficient (0.001% Mg) (N = 8) ingredients for 17 days. All animals were time marked with a combination of 0.1 mol nitrilotriacetato lead and 0.1 mol nitrilotriacetato zinc (2mg Pb/kg body weight) on days 0, 7 and 14 into incisor dentine. Blood samples were obtained on days 10 and 17 in order to measure Ca, Mg, P and alkaline phosphatase activity levels in serum; moreover, hypomagnesaemia and hypercalcaemia were confirmed. After the 17th day, rats were sacrificed humanely under anaesthesia and mandibular incisors were removed. Dentine formation of right mandibular incisors was assessed (time marking lines); furthermore, Ca, P, Mg and sulphur (S) concentrations as well as Ca/P molar ratio were determined in left mandibular incisors based on contiguous measurement points at 2 microm intervals from dentine pulp to dentine of the lingual aspect via X-ray analysis. Additionally, proteoglycan distribution was observed in other Mg-deficient rat dentine. These findings demonstrated decreases in body weight, incisor formation and incisor length in Mg-deficient rats. Mg and S levels increased in the defect layers, whereas proteoglycan decreased. This phenomenon was possibly attributable to condensation of Mg and S contents consequent to decreased dentine formation during Mg-deficiency and a transient increase in Mg due to transport of Mg as a result of inhibition of cell proliferation in soft tissues.     

Composition of whole unstimulated saliva of human infants

Whole unstimulated saliva of 168 infants aged 3 days to 12 months was analysed. The concentration of Ca, Mg and Cl was higher in the saliva of infants than in adults. The concentration of phosphate, IgA, amylase and pH was lower in infants; Na, K and total protein did not differ significantly. A wide range of all the concentrations was observed in the saliva of infants. No significant difference was found between the salivary composition of male versus female or of breast-fed as compared to bottle-fed infants. No difference before and after eruption of teeth was detected. Significant differences between different age groups were observed in the concentrations of Na, K, Cl, phosphate, protein, amylase and pH. No significant differences were found in Ca, Mg and IgA concentrations within the first year. A negative correlation between the age of the infants and the concentrations of Na, K, Cl and total protein was observed. A positive correlation was found for phosphate and amylase as a function of age.     

Effect on human teeth of renal transplantation: a postmortem study

Extracted teeth from five deceased patients treated by renal transplantation were examined radiographically and histologically, and compared with teeth from healthy persons of approximately the same age. In three of the patients with a renal transplant, the radiographs showed normal pulp chamber sizes, but histologic examination revealed a widened predentin zone, approximately four times greater than in the controls. In two of the patients the radiographs showed marked reduction of the pulp chamber size. The histologic changes of these teeth were mainly an extensive amount of secondary dentin along the pulp chamber walls and the root canals, with a markedly reduced pulp space. One explanation for the difference between the patients was that patients with extensive pulp calcifications were given a higher total amount of corticosteroids than patients with a widened predentin zone.     

The effect of beta-sympathomimetic stimulation on parotid salivation in the red kangaroo (Macropus rufus)

Salivation was stimulated by intracarotid isoprenaline infusion given alone or combined with acetylcholine. By itself, isoprenaline (0.12-1.2 nmol kg-1 min-1) stimulated flow rates of 0.037-0.233 ml min-1 (2.77-10.5 microliters/g gland per min). Salivary Na, Cl, PO4 and total solute concentrations were positively correlated with flow; K, Mg and urea were negatively correlated with flow; and Ca, H+, HCO3, protein and amylase activity were not correlated with flow. Relative to cholinergic saliva, isoprenaline-evoked saliva had higher levels of amylase activity, urea, protein, K, Mg, H+, PO4 and Cl but lower osmolality, Na, Ca and HCO3. At a steady flow (1 ml min-1), isoprenaline infusion (0.3 nmol kg-1 min-1) superimposed on a pre-existing acetylcholine infusion increased salivary amylase activity, protein, urea, K, Mg, Cl and PO4, reduced HCO3 and did not alter Na, Ca, H+ and osmolality. Superimposition of isoprenaline infusion (0.5 nmol kg-1 min-1) on a low-level acetylcholine infusion increased flow rate by 400-900%. Excretion rates of K, Mg, Cl and PO4 were higher and Ca lower than predicted for saliva secreted at equivalent flows during acetylcholine stimulation. Na, H+ and HCO3 were as predicted for the same flow rate under cholinergic stimulation. The simplest coherent interpretation of these data is that isoprenaline affects transport of protein and ions at the end organs, but has little effect on the resting transport characteristics of the striated and excretory ducts of the kangaroo parotid, in accord with the known nerve distribution of this gland.     

Expression of adenosine triphosphate P2X3 receptors in rat molar pulp and trigeminal ganglia

OBJECTIVE: The objective of this study was to investigate the expression of adenosine triphosphate P2X3 receptor subunits in rat molar pulp and trigeminal ganglia and their relationship to substance P. STUDY DESIGN: Rat molar pulp and trigeminal ganglia were fixed and sectioned. Double immunostaining with anti-P2X3 and anti-substance P were used to localize P2X3 and substance P expression simultaneously with different stains. RESULTS: P2X3 immunoreactivity (IR) fibers were present in root and coronal pulp. P2X3-IR fibers formed subodontoblastic plexus and advanced into the predentin and dentin. P2X3-IR neurons were localized in small and medium-sized cells in trigeminal ganglia. Colocalization of P2X3 and substance P was not found in either molar pulp or trigeminal ganglia. CONCLUSION: The results of this study indicated that adenosine triphosphate in pulp tissues may stimulate a subpopulation of non-substance P trigeminal afferent fibers through activation of P2X3 receptors.     

A longitudinal study of crevicular fluid in periodontal disease in beagles

A longitudinal study on the composition of crevicular fluid (CF) and serum was carried out in seven beagle dogs during a period from health to 16 weeks of gingivitis and then 8–10 weeks of ligature induced periodontitis (LIPD). The fluids were collected at weekly intervals and the pH and the concentrations of Ca, Mg, Na, and K and the protein profile were determined. Also at weekly intervals, the plaque index, gingival index, calculus index, and pocket depth and attachment loss were recorded for the teeth from which crevicular fluid was collected. Radiographs were taken on the 0 day and after the dogs were sacrificed. Histopathological studies were carried out following sacrifice of the dogs, and the distances between the cemento-enamel junction and the coronal end of the junctional epithelium and the cemento-enamel junction and the crest of the alveolar bone were measured. A two-way ANOVA analysis of the two fluids (CF and serum) and of the two diseases (gingivitis and periodontitis) showed significant differences between the two fluids and between the two diseases. Further statistical analysis showed that in serum none of the constituents studied differed significantly between gingivitis and LIPD, but a significant rise in the concentrations of Ca, Mg, and K was observed in CF during LIPD. The pH of CF was significantly lower during LIPD, but no significant change was observed in the concentration of Na ion. An apparent relationship was observed only between the concentration of K ion in CF and the attachment loss during LIPD. The serum protein profile remained unchanged throughout the period of this study. During gingivitis the CF protein profile was identical to that of serum, but during LIPD a new protein peak appeared. This material had a molecular weight of < 200,000 daltons. Histopathological and radiographic analysis showed bone loss in all but one dog during LIPD. Histopathological study also showed no significant difference in the distance between CEJ and the coronal end of the junctional epithelium between the ligated and the non-ligated sides. This study showed that in beagle dogs the CF differed significantly from that of serum. Also, LIPD caused significant changes in both ionic concentrations and protein profile of crevicular fluid.