92242636
Abe K Masatomi Y Nakajima Y Shintani S Moriwaki Y Sobue S Ooshima T
The occurrence of interglobular dentin in incisors of hypophosphatemic mice fed a high-calcium and high-phosphate diet.
In: J Dent Res (1992 Mar) 71(3):478-83
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.
Institutional address:
Department of Pedodontics
Osaka University Faculty of Dentistry
Japan.
*****JOURNAL OF DENTAL RESEARCH*****
90062734
Abe K, Ooshima T, Masatomi Y, Sobue S, Moriwaki Y
Microscopic and crystallographic examinations of the teeth of the X-linked hypophosphatemic mouse.
J Dent Res 1989 Nov;68(11):1519-24
ABSTRACT:
Teeth from the C57BL/6J-Hyp mouse (Hyp mouse) were examined histologically, radiographically, and crystallographically. Microscopic examinations of the ground sections, the decalcified and H-E-stained sections, and the contact microradiograms of molars and incisors from the Hyp mouse showed several abnormalities--such as large pulp chamber, wide predentin, thin dentin at the pulp floor, and multiple occurrences of interglobular dentin. Powder and microbeam x-ray diffraction analyses showed that the crystallinity of hydroxyapatite in incisor globular dentin from the Hyp mouse was higher than that in incisor dentin from the normal mouse. On the other hand, the findings of transmission electron microscopy demonstrated that the sizes of hydroxyapatite crystals of globular dentin in the Hyp incisor were larger than those in normal incisor dentin. These results demonstrated that the findings in Hyp mouse teeth were in accord with those of human XLH teeth.
Address:
Department of Pedodontics
Osaka University Faculty of Dentistry
Japan.
*****JOURNAL OF DENTAL RESEARCH*****
92210888
Limeback H Schlumbohm C Sen A Nikiforuk G
The effects of hypocalcemia/hypophosphatemia on porcine bone and dental hard tissues in an inherited form of type 1 pseudo-vitamin D deficiency rickets.
In: J Dent Res (1992 Feb) 71(2):346-52
The effects of Vitamin D deficiency rickets on the formation of mineralized dental tissues were studied in a breed of pigs which had moderate and marked hypocalcemia because of an inherited defect in the renal production of the biologically-active Vitamin D metabolites. Affected piglets developed classical symptoms of rickets which were fatal unless Vitamin D supplements were given. The dissected mandibles of homozygous (rickets) and heterozygous (normal) pigs were photographed and radiographed. Compared with those of normal pigs, the mandibles of homozygous pigs demonstrated slowed development/eruption of permanent teeth, under-mineralized bone, underdeveloped dentin (enlarged pulp chambers), interglobular dentin, and enamel hypoplasia. Enamel defects in rachitic pig teeth were difficult to observe radiographically, but could be detected visually and by SDS-PAGE analysis of the enamel protein components of developing and maturing enamel. There was significant retention of amelogenins in the enamel maturation zones of developing molars taken from rachitic pigs, but there was no obvious difference in the patterns of amelogenin processing.
Institutional address:
Faculty of Dentistry
University of Toronto
ON
Canada.
*****ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY*****
89015780
Schwartz S, Scriver CR, Reade TM, Shields ED
Oral findings in patients with autosomal dominant hypophosphatemic bone disease and X-linked hypophosphatemia: further evidence that they are different diseases.
Oral Surg Oral Med Oral Pathol 1988 Sep;66(3):310-4
ABSTRACT:
Oral examinations were performed on 5 patients with hypophosphatemic bone disease (HBD) (2 males and 3 females), 14 patients with X-linked hypophosphatemia (XLH), and 4 affected XLH relatives (6 males and 12 females). The control subjects were the unaffected siblings and parents of the patients and unrelated healthy, gender- and age-matched subjects. Serum phosphorus values were the same by disease type and gender in patients with HBD and XLH. They shared certain dental abnormalities, in particular pulpal necrosis and large pulp spaces. However, only patients with XLH had Class III malocclusions and mild enamel defects, and males with XLH had more severe occlusal and enamel defects than females with XLH. Different dental phenotypes are further evidence that XLH and HBD are different diseases. The dental abnormalities were not prevented by treatment, instituted early in life, which raised serum phosphorus to the near normal range.
Address:
Department of Dentistry
Montreal Children's Hospital
Quebec
Canada.
*****ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY*****
88143604
Abe K, Ooshima T, Lily TS, Yasufuku Y, Sobue S
Structural deformities of deciduous teeth in patients with hypophosphatemic vitamin D-resistant rickets.
Oral Surg Oral Med Oral Pathol 1988 Feb;65(2):191-8
ABSTRACT:
Structural deformities of deciduous teeth from patients with hypophosphatemic vitamin D-resistant rickets (HVDRR) (1 male and 2 female patients) were examined by means of transmitted light microscopy, contact microradiography, and x-ray microanalysis. Freshly extracted teeth were fixed in formalin and subsequently hemisected longitudinally through the midline. One half was prepared for ground sections and the other half for decalcified sections. Neither gross nor microscopic abnormalities were present in enamel of patients with HVDRR. The concentration of calcium and phosphorus and the calcium/phosphorus ratio of the enamel of patients with HVDRR were nearly equal to those of normal teeth, although the degree of radiopacity was less in HVDRR. On the other hand, numerous microscopic abnormalities in the dentin of patients with HVDRR were found, such as interglobular dentin, wide predentin zones, and tubular defects. The concentration of phosphorus in the dentin of a patient with familial HVDRR was extremely low. Furthermore, formation of reparative dentin was observed at the pulp horn of teeth in patients with HVDRR that had been subjected to definite attrition at the corresponding dentin site.
Address
Osaka University Faculty of Dentistry
Japan.
****ORAL SURGERY,ORAL MEDICINE,AND ORAL PATHOLOGY****
83013944
Rakocz M Keating J 3d Johnson R
Management of the primary dentition in vitamin D-resistant rickets.
In: Oral Surg Oral Med Oral Pathol (1982 Aug) 54(2):166-71
Vitamin D-resistant rickets (familial Hypophosphatemia) is a systemic disease secondary to defective renal-tubular reabsorption of phosphate. The major oral manifestations are spontaneous abscesses in a caries-free dentition. Pulpotomies or extractions were frequently described in the dental literature as the therapies of choice. This article presents a new prophylactic approach utilizing zinc oxide--eugenol pulpectomies and full crown coverage in an attempt to retain the primary dentition and prevent abscess formation.
**********ASDC JOURNAL OF DENTISTRY FOR CHILDREN*****
92042986
Larmas M, Hietala EL, Simila S, Pajari U
Oral manifestations of familial hypophosphatemic rickets after phosphate supplement therapy: a review of the literature and report of case.
ASDC J Dent Child 1991 Jul-g;58(4):328-34
ABSTRACT
The patient was a seven-year-old boy with familial vitamin D- resistant hypophosphatemic rickets. His mother, and her mother, were also affected. Before phosphate treatment was introduced in the patient, an impaired incorporation of calcium, and its exchange with sodium, was thought to be the principal etiological factor in the formation of globules. Supplementation therapy then resulted in a less elevated Ca/P ratio in the root area of the affected teeth, as well as a cure for the boy's bone structure. What the therapy did not cure was the globular appearance of the dentin and the hypomineralized stripe of pulpal horn extending to the cusp tips, an apparent permanent outcome of the disease.
ADDRESS
Institute of Dentistry
University of Oulu
Finland.
IS - 0022-0353
**********ASDC JOURNAL OF DENTISTRY FOR CHILDREN*****
90264564
Fadavi S, Rowold E
Familial hypophosphatemic vitamin D-resistant rickets: review of the literature and report of case.
ASDC J Dent Child 1990 May-Jun;57(3):212-5
ABSTRACT
Familial hypophosphatemia, commonly known as vitamin D-resistant rickets, is inherited in an x-linked dominant manner. This condition is characterized by impairment of renal tubular reabsorption of inorganic phosphate and is inherited as a sex-linked dominant trait. Early clinical signs, usually detected about two years of age, included lateral bowing of the lower extremities, scoliosis, and frontal bossing. Characteristic dental findings are often the first clinically noticeable signs of the disease. This case report describes the typical dental findings in a 10-year old Hispanic female.
Review, Tutorial
ADDRESS
Department of Pediatric Dentistry
University of Illinois
Chicago.
*****ASDC JOURNAL OF DENTISTRY FOR CHILDREN*****
86224833
Herbert FL
Hereditary hypophosphatemia rickets: an important awareness for dentists.
In: ASDC J Dent Child (1986 May-Jun) 53(3):223-6
Because X-linked hypophosphatemia VDRR is reported to be the most common form of rickets in the United States today, it is important for dentists to be aware of this condition. Characteristic dental findings are often the first clinically noticeable signs of the disease. The confirmation of hypophosphatemia with dental findings will permit early diagnosis and prevent crippling rachitic
deformities, otherwise certain to follow. Reports in the literature confirm the validity of conservative, prophylactic full coverage restorations in patients with VDRR.
*****ASDC JOURNAL OF DENTISTRY FOR CHILDREN*****
86112764
Breen GH
Prophylactic dental treatment for a patient with vitamin D-resistant rickets: report of case.
In: ASDC J Dent Child (1986 Jan-Feb) 53(1):38-43
Spontaneous oral dental abscesses in caries-free teeth has been a common sequela in patients with vitamin D-resistant rickets (VDRR). A successful attempt has been made to prevent such abscesses in a 41/2-year-old boy with VDRR by covering susceptible teeth with chrome crowns.
**********ANNUAL NEW YORK ACADAMY OF SCIENCE********
95305445
Boskey AL
Osteopontin and related phosphorylated sialoproteins: effects on mineralization.
REVIEW
Ann N Y Acad Sci 1995 Apr 21;760:249-56
ABSTRACT
Osteopontin is one of a family of phosphorylated sialoproteins found in the extracellular matrices of mineralized connective tissues. Solution studies from a variety of laboratories have shown that while some of these proteins (e.g., osteopontin, dentin sialoprotein) inhibit calcium phosphate production, others, such as bone sialoprotein, can act as a nucleator of calcium phosphate formation.
The differences in the behaviors of these proteins can be related to their interactions with mineral crystal nuclei and crystal growth sites. The specificity of these interactions, in turn, can be related to differences in the primary structures of the sialoproteins and to the extent to which they are phosphorylated. In vitro systems for the study of osteopontins and osteopontin-related protein effects on mineral deposition are described, along with mechanisms explaining the contrasting abilities of the polyglutamate-containing bone sialoprotein to act as a nucleator, while the polyaspartate- containing osteopontin and dentin sialoproteins inhibit calcium phosphate formation and growth.
Hospital for Special Surgery
New York
New York 10021
USA.
92378809
Mongiorgi R, Tateo F, Monti S, Prati C,Bertocchi G
Calcium oxalate smear layer: mineralogical and crystallographic study.
Boll Soc Ital Biol Sper 1992 Feb;68(2):99-103
ABSTRACT
Different methods to reduce dentine hypersensitivity have been tested by means of oxalate treatments. Natural material (20 teeth) and commercial oxalates have been employed. As a result the dentinal tubules are filled by small crystals preventing dental disease. Permeability measurements have been performed in order to quantify results. The composition of the synthetic smear layer produced after oxalate treatment have been investigated by powder diffraction method suggesting calcium oxalate formation.
Address
Department of Mineralogical Sciences
University of Bologna
Italy.
87158982
Sakakura Y
Effects of parathyroid hormone on odontogenesis of the mouse embryonic molar tooth in vitro.
Calcif Tissue Int 1987 Jan;40(1):49-54
ABSTRACT
Mandibular first molars of 17-day-old mouse embryos were cultured in vitro to examine the histological effects of various concentrations of parathyroid hormone (PTH) on odontogenesis of the molars. PTH did not affect the cytodifferentiation of mesenchymal cells into preodontoblasts but inhibited that of preodontoblasts into odontoblasts. Consequently, the odontoblasts failed to undergo dentinogenesis. On the other hand, inner enamel epithelium achieved terminal cytodifferentiation into secretory ameloblasts and these cells partially formed enamel in spite of the absence of dentin. All treated molars showed the same histological disturbances and these effects were independent of PTH dose. The present study indicated that PTH had an influence on mesenchyme-derived cells, inhibiting both the differentiation of odontoblasts and the formation of predentin and dentin.
79014059
Gozariu L, Barabas E
45Ca uptake in tooth germs: effects of parathormone, calcitonin and propranolol.
Endocrinologie 1978 Jul-Sep;16(3):213-7
ABSTRACT
Tooth germs harvested from 6-day-old rats were incubated in a 45Ca-containing medium for 6 hours. The addition of PTH consistently stimulated the increase in 45Ca uptake, while calcitonin significantly reduced both the PTH-stimulated incorporation and the spontaneous one. Dibutyrul CAMP (3.5 mM) had no effects. Propranolol
significantly inhibited the spontaneous and stimulated 45Ca uptake. Results obtained support the concept that the two hormones have a clear influence on calcium entering the tooth germs in full calcification process probably by early membrane effect.
**********INTERNATIONAL DENTAL JOURNAL*********
77050643
Witkop CJ
Clinical aspects of dental anomalies.
Review
Int Dent J 1976 Dec;26(4):378-90
ABSTRACT
Many inherited disorders have oral manifestations which can be detected on dental radiographs as alterations in the morphology or chemical composition of the teeth. Thus the dentist may be the first to detect disorders of development and metabolism of importance to the general health of the patient and his family. In one group of conditions the pulp chamber is larger than normal. This may be associated with trodontism in such conditions as polyploidy of the - X chromosome and trisomy-21 or Down's syndrome. Taurodontism also occurs in a variety of other syndromes including the tricho-dento-osseous syndrome described by Robinson, Miller and Worth (1966) and Mohr's syndrome. It may also be associated with scanty hair endoligodentia. In certain metabolic conditions the pulp chamber may be enlarged but the teeth are of relatively normal from (cynodont).
Such cases include hypophosphatemic vitamin D-resistant and dependent rickets, pseudo-hypoparthyroidism otodental syndrome and hypophosphatasia. Small pulp chambers and associated anomalies of root morphology also occur in hereditary disorders either alone or as part of various syndromes such as dentino-osseous dysplasia and brackioskeletogenital syndrome. Dentinogenesis imperfecta may occur alone or as one manifestation of osteogenesis imperfecta. Other developmental defects including pulpal dysplasia, labodontia and dens invaginatus are also associated with small pulp chambers.
****INTERNATIONAL JOURNAL OF PEDIATRIC DENTISTRY****
92399398
Chadwick BL, Aldred MJ
An unusual giant cell lesion in a child with vitamin D-resistant rickets.
Int J Paediatr Dent 1992 Apr;2(1):41-5
ABSTRACT
This paper reports the presence of a focus of giant cells in a sinus tract associated with an abscessed primary tooth in a patient with vitamin D-resistant rickets. The relevance of this giant cell lesion to the systemic disorder is discussed.
Address
Department of Child Dental Health
University of Wales College of Medicine.
93029614
Seto H, Ihara F, Shimizu M, Kageyama M, Futatsuya R, Kakishita M
Effect of diets containing different levels of calcium, phosphate, and vitamin D3 on tooth uptake of 47Ca-chloride in rat models: comparison with bone uptake.
Radiat Med 1992 Jul-Aug;10(4):131-4
ABSTRACT
The effect of dietary manipulation on global tooth uptake of 47Ca-chloride was evaluated in three rat models of metabolic bone diseases verified by histologic bone study. The 24-hr tooth uptake of 47Ca-chloride was significantly decreased in the osteomalacic group, and was increased in the osteoporotic group at the fourth week. Tooth uptake closely paralleled femoral uptake at a correlation coefficient of 0.73 (p less than 0.01). The uptake of 47Ca-chloride in tooth was found to be more affected by dietary manipulation than that in femur in our rat models.
Address:
Department of Radiological Sciences
Faculty of Medicine
Toyama Medical and Pharmaceutical University
Japan.
92179541
Nishino M, Kamada K, Arita K, Takarada T
[Dentofacial manifestations in children with vitamin D-dependent Rickets type II]
Shoni Shikagaku Zasshi 1990;28(2):346-58
(in Japanese)
ABSTRACT
Calcification of the teeth, size of the teeth and dental arches, facial growth and calcification of the carpal bones were studied in three children with clinically different severities of vitamin D-dependent rickets (DDR), type II, with alopecia, which is 1,25-dihydroxyvitamin D-receptor-defect rickets and is particularly resistant to treatment with calciferol analogues. They were treated in a pediatric clinic with large doses of 1 alpha-hydroxyvitamin D3(1alpha-(OH)D3) and 2 g/day of calcium lactate. The results were as follows:
1. Hypoplasia of enamel of the deciduous teeth was not found.
2. In the deciduous teeth, large pulp chambers and thin dentin were seen in radiographs before treatment. In patients 1 and 2, these abnormalities were reversed by treatment. In patient 3, who had the severest manifestations, large pulp chambers and thin dentin decreased but still remained.
3. Growth of permanent teeth was retarded before treatment and during resistance to treatment. After effective medication, it caught up and was corrected.
4. Problems concerning maxillary and mandibular growth were not found. However Nasions of three patients were more front and lower and Orbitals were lower than standard.
5. In patients 1 and 2, the calcification of carpal bones was accelerated and in patient 3 retarded.
6. Mesiodistal dimensions of erupted deciduous and permanent teeth were within the standard range, except for patient 3, who had smaller lower deciduous teeth.
7. A ground section of the extracted upper right first deciduous molar from patient 3 showed abundant inter-globular dentin and lack of pre-dentinal layer. From the above findings, it was felt that in all probability dentinogenesis was disturbed by the DDR type II. Abnormally large pulp chambers and thin dentin could be corrected by effective medication. In patients with vitamin D-dependent rickets type II, oral hygiene for caries prevention is the most important procedure, because the pulp will be infected immediately after initiation of dental caries. After effective medication, permanent teeth and jaw bones will probably grow normally.
Address
Department of Pediatric Dentistry
Tokushima University.
*****AMERICAN JOURNAL OF HUMAN GENETICS*****
90178076
Shields ED Scriver CR Reade T Fujiwara TM Morgan K Ciampi A Schwartz S
X-linked hypophosphatemia: the mutant gene is expressed in teeth as well as in kidney.
In: Am J Hum Genet (1990 Mar) 46(3):434-42
Mutation at a locus (HPDR) on the X chromosome (McKusick 30780[HPDR1]; 30781 [HPDR2]) causes impaired renal phosphate transport, hypophosphatemia, and an associated impairment in the process of mineralization in bone and teeth (X-linked Hypophosphatemia [XLH]).
We measured the dental pulp profile area (PRATIO [= pulp area/tooth area]) and serum phosphorus (Pi) values in uniformly treated XLH patients (six males, 81 teeth, 1,457 Pi values; 11 females, 129 teeth, 1,439 Pi values). Serum Pi values, reflecting the metabolic environment of tooth development, were obtained by repeated measurement between 1 mo and 26 years of age during treatment. PRATIO values calculated from standardized Rinn radiographs were used as outcome measurements of tooth development in XLH patients and in age-matched controls (12 males, 100 teeth; 27 females, 275 teeth). Age-dependent serum Pi values were not different in the treated XLH males and females. In teeth forming primary dentin there was no gene dosage effect on PRATIO values apparent in subjects below 15 years of age.
However, in teeth forming secondary dentin a gene dosage was found in the subjects aged 15 to 25 years: XLH male teeth (n = 65) mean +/- SD= 0.163 +/- 0.046; XLH female teeth (n = 75) mean +/- SD = 0.137 +/- 0.039; control teeth (n = 209) mean +/- SD = 0.116 +/- 0.023; (higher PRATIO values mean less development or mineralization of secondary dentin); differences in these PRATIO values (males vs. female and XLH vs. control) were significant by mixed-model analysis of variance.(ABSTRACT TRUNCATED AT 250 WORDS)
Institutional address:
Craniofacial Genetics
Faculty of Dentistry
McGill University
Montreal Children's Hospital
Quebec
Canada.
*****AMERICAN JOURNAL OF MEDICAL GENETICS*****
83201326
Cole DE Fraser FC Glorieux FH Jequier S Marie PJ Reade TM Scriver CR
Panostotic fibrous dysplasia: a congenital disorder of bone with unusual facial appearance, bone fragility, hyperphosphatasemia, and hypophosphatemia.
In: Am J Med Genet (1983 Apr) 14(4):725-35
We report a boy with unusual facial appearance, melanotic patches("coast-of-Maine" type), myelofibrosis, recurrent femoral fractures,and widespread fibrous dysplasia of bone. Biochemical findings included raised serum alkaline phosphatase (bone isozyme) and 1,25-(OH)2 vitamin D, and low serum phosphorus levels. Elevated urinary excretion rates of total hydroxyproline, glycylproline, and gamma-carboxyglutamic acid indicated increased turnover of bone matrix. Transiliac bone biopsy showed a dearth of marrow elements, greatly increased bone turnover, and absence of normal trabecular organization. Serial radiographs showed progressive cortical thinning and loss of bony trabeculae. Calcitonin and etidronate treatments had no lasting effect on the progressive bone disease. The term "panostotic fibrous dysplasia" is suggested for this condition.
*****ARCHIVES OF ORAL BIOLOGY*****
90088217
Abe K Ooshima T Sobue S Moriwaki Y
The crystallinity of human deciduous teeth in hypophosphataemic vitamin D-resistant rickets.
In: Arch Oral Biol (1989) 34(5):365-72
Five teeth were obtained from three patients with hypophosphataemic vitamin D-resistant rickets (HVDRR) and five corresponding sound teeth from five healthy children. According to powder X-ray diffraction analysis, the half-peak breadths of (310) and (002)
reflections of HVDRR dentine were smaller than those of normal dentine. Splitting fractions obtained from i.r. spectral analysis of HVDRR dentine powder were larger than those of normal. Microbeam X-ray diffraction analysis showed that the relative half-peak breadths of globular dentine in ground sections of HVDRR teeth were smaller than those of normal circumpulpal dentine. Transmission electron microscopy demonstrated that the hydroxyapatite crystals of globular dentine in HVDRR teeth were larger than those of normal dentine. Thus the crystallinity of deciduous tooth dentine in HVDRR was greater than that of normal dentine, mainly because of the large hydroxyapatite crystals in HVDRR globular dentine.
Institutional address:
Department of Pedodontics
Osaka University Faculty of Dentistry
Japan.
*****ARCHIVES OF ORAL BIOLOGY*****
95329004
Appleton J
Changes in the plasma electrolytes and metabolites of the rat following acute exposure to sodium fluoride and strontium chloride.
In: Arch Oral Biol (1995 Apr) 40(4):265-8
Acute exposure of rats to strontium or fluoride by i.p. injection of sodium fluoride or strontium chloride resulted in a systemic response in which changes occurred in the plasma electrolytes and metabolites.Strontium resulted in a rapid but temporary hypercalcaemia while fluoride produced a temporary hypocalcaemia. There was no significant hypophosphataemia after fluoride and only a transient hypophosphataemia with strontium. There was some indication of kidney damage and a general stress response following fluoride injection. These results do not support the hypothesis that interglobular dentine is associated with hypophosphataemia or hypoplastic enamel with hypocalcaemia and are in conflict with the observation that the formation of interglobular dentine following the injection of lead acetate is associated with hyperphosphataemia and hypercalcaemia.
Institutional address:
University of Liverpool
Department of Clinical Dental Sciences
School of Dentistry.
*****ARCHIVES OF ORAL BIOLOGY*****
83255950
Shellis RP
Structural organization of calcospherites in normal and rachitic human dentine.
In: Arch Oral Biol (1983) 28(1):85-95
The structure of human dentine affected by familial hypophosphataemic rickets was investigated by polarized light and electron microscopy.Within the calcospherites both radially-orientated and collagen-orientated crystals were present, in approximately equal numbers.This was so, but less distinctly, in the calcospherites of normal dentine. It is concluded that dentine mineralizes entirely by formation of calcospherities which coalesce. It is proposed that matrix vesicles are probably responsible for the initiation of mineralization, and that growth of the calcospherites may depend on scavenging of inorganic pyrophosphate by the first-formed crystals. Growth of these crystals is thus poisoned but the resulting removal of inhibition allows deposition of further crystals by precipitation and by nucleation on collagen. The rachitic structure of dentine appeared to be due to slow calcospherite growth, probably as a result of the depressed serum phosphate characteristic of the disease.
*****BIRTH DEFECTS ORIGINAL ARTICLE SERIES*****
81087279
Diner H Chou MD
Dental diagnostic problems of potential genetic significance: the dental practitioner as geneticist in the developmental disabilities clinic.
In: Birth Defects (1980) 16(5):151-70
Diseases/GE>
Administration File>
A high incidence of aberrant dental formation can be anticipated in developmentally disabled children, particularly where the etiologic factors for developmental retardation are presumably of organic origin. The dentist, practicing in the developmental clinic, must frequently determine the developmental significance of such dental variation. In this capacity, his familiarity with the dental features of genetic disease can contribute significantly to more precise diagnosis.
*****BIRTH DEFECTS ORIGINAL ARTICLE SERIES*****
75109614
Archard HO
The dental defects of vitamin D-resistant rickets.
In: Birth Defects (1971 Jun) 7(7):196-9
Clinical, roentgenographic and morphologic features of teeth from patients with vitamin D-resistant rickets are described based on a study of 28 teeth from 5 patients. Clinically normal teeth become
symptomatic and develop roentgenographic evidence of periapical infection. The exposed dentin is vulnerable to microbial invasion because of a defective globular-type calcification as seen in both ground and decalcified sections. The changes are distinctive and pathognomonic, but the effects of therapy (vitamin D) have not yet been ascertained.
*****CALCIFIED TISSUE INTERNATIONAL*****
91152621
Daley TD Jarvis A Wysocki GP Kogon SL
X-ray microanalysis of teeth from healthy patients and patients with familial hypophosphatemia.
In: Calcif Tissue Int (1990 Dec) 47(6):350-5
Energy-dispersive X-ray microanalysis was used to determine calcium/phosphorous (Ca/P) ratios in undecalcified teeth, and the sulfur (S) content of dentin of decalcified teeth from normal patients and patients with familial hypophosphatemia, in an attempt to determine the effect of phosphorus deficiency. The results showed that normal enamel has a slightly elevated Ca/P ratio compared to pure apatite. Enamel from a tooth of an untreated patient with hypophosphatemia exhibited a significantly higher Ca/P ratio than the normal teeth whereas enamel from teeth of an intermittently treated patient exhibited Ca/P ratios similar to pure apatite. Surprisingly, globular dentin in the same teeth showed a Ca/P ratio similar to that of globular dentin of the untreated tooth. The decalcified dentin from teeth of three hypophosphatemic patients and eight normal patients showed a S peak which varied widely in concentration. No detectable differences could be found between normal and diseased teeth.
Institutional address:
Department of Pathology
Faculty of Dentistry
University of Western Ontario
London
Canada.
*****JOURNAL DE BIOLOGIE BUCCALE*****
92041779
Hietala EL Larmas MA
Mineral content of different areas of human dentin in hypophosphataemic vitamin D-resistant rickets.
In: J Biol Buccale (1991 Jun) 19(2):129-34
Calcium, phosphorus, fluoride, sodium, magnesium and zinc estimations were carried out on teeth from a patient with hypophosphataemic vitamin D-resistant rickets (HVDRR) and from a patient with acquired rickets with the aim of determining differences in the composition of dentine in these two types of rickets. Normal deciduous teeth served as controls. Mineral analyses were carried out using an electron probe micro-analyser after carefully polishing the hemisected specimens. After the analyses the specimens were coated with gold-palladium for more detailed SEM studies. The Ca, P, F and Zn contents of the calcospherites were normal, while there was more Na and less Mg in the dentine of HVDRR teeth than of controls. The significance of this remains unexplained. The mineral content of the interglobular spaces was very limited, but there was more Zn in these than in other parts of the HVDRR teeth, in the acquired rickets teeth or in the control teeth. The excess of Zn in the interglobular spaces is thought to have an effect on the mineralisation process in HVDRR teeth. The globular nature of HVDRR teeth is thought to be genetically controlled and the result of a reduction in the number of calcification nuclei. The globular nature of the HVDRR teeth was not due to lack of Ca and P, as the serum levels of these minerals were maintained within normal limits during tooth development by controlled phosphate supplementation. Because in acquired rickets the globules were seen at the developmental stage that the teeth had reached when the nutritional disturbance occurred, the fault in mineralisation is thought to be different from that in HVDRR teeth.(ABSTRACT TRUNCATED AT 250 WORDS)
Institutional address:
Institute of Dentistry
University of Oulu
Finland.
***ORAL SURGERY,ORAL MEDICINE,ORAL PATHOLOGY,ORAL RADIOLOGY AND***
95323598
Hall RK Phakey P Palamara J McCredie DA
Amelogenesis imperfecta and nephrocalcinosis syndrome. Case studies of clinical features and ultrastructure of tooth enamel in two siblings.
In: Oral Surg Oral Med Oral Pathol Oral Radiol Endod (1995 May)
79(5):583-92
This article describes the enamel ultrastructure and clinical features in two siblings with the little known syndrome of Amelogenesis imperfecta and nephrocalcinosis. Nephrocalcinosis was diagnosed by x-ray examination of the abdomen, intravenous pyelography, ultrasonography, and computed tomography scan. Amelogenesis imperfecta was diagnosed from clinical and histologic examinations. The affected enamel was hypoplastic (approximately 0.2 mm thick), positively birefringent, generally aprismatic, porous, and consisted of loosely packed, randomly orientated, thin (approximately 10 nm wide), ribbonlike crystals. The enamel surface was rough, extensively cracked, and covered with ovoid or globular protrusions. Observations showed that in this case hypoplasia, hypocalcification, or hypomaturation defects were present in the same tooth, indicating that both secretory and maturation phases may have been affected. The study suggested the possibility of an abnormality in interstitial matrix, which could lead to dystrophic calcification in the kidney and abnormal tooth enamel formation. It also suggested the possibility of involvement of two separate but closely linked genes.
Institutional address:
Department of Dentistry
Royal Children's Hospital
Melbourne
Australia.
*****PEDIATRIC DENTISTRY*****
92051526
Seeto E Seow WK
Scanning electron microscopic analysis of dentin in vitamin D-resistant rickets--assessment of mineralization and correlation with clinical findings.
In: Pediatr Dent (1991 Jan-Feb) 13(1):43-8
In vitamin D-resistant rickets, the basic dental defect is manifested in dentin. Structural investigations of rachitic dentin by light and scanning electron microscopy have revealed the presence of calcospherites separated by interglobular dentin. This occurs when calcospherites do not fuse. This study investigated the morphology and ultrastructure of rachitic dentin with three different clinical and histologic grades of severity to determine if dentin mineralization can be quantified by calcospherite size and degree of calcospherite fusion. The results showed that a correlation existed between calcospherite size, calcospherite fusion, and the degree of dentin mineralization. The present findings indicate that calcospherite size and calcospherite fusion are valid parameters for assessing and quantifying dentin mineralization. In addition, an SEM grading of severity was established based on these two parameters. The SEM grades correlated directly with the clinical and histologic grades, suggesting that the dental clinical manifestations are a reflection of the underlying morphology of the dentin and the extent of abnormal dentin mineralization.
Institutional address:
University of Queensland Dental School
Brisbane
Australia.
*****PEDIATRIC DENTISTRY*****
91351905
Seow WK
The effect of medical therapy on dentin formation in vitamin D-resistant rickets.
In: Pediatr Dent (1991 Mar-Apr) 13(2):97-102
Vitamin D-resistant rickets (VDRR) is one of the most common forms of rickets in developed countries today. Widely practiced medical treatment regimens usually include replacing phosphorus and calcium lost through urination. In this study, 20 teeth from five patients with varying grades of dental manifestation of VDRR were examined to relate the institution of medical therapy with any observed improvement of dentin calcification. In all the teeth examined, there was no correlation between the time of appearance of dentin changes and the commencement of medical therapy. Furthermore, in several teeth from the patients with Grade III severity, there were no signs of improvement in dentin calcification even after prolonged medical therapy. This study suggests that current medical treatment of VDRR has no beneficial effect on the dental structures and dentists should not rely on medical treatment to correct dental calcification problems.
Institutional address:
University of Queensland Dental School
Australia.
*****PEDIATRIC DENTISTRY*****
90287790
Seow WK Romaniuk K Sclavos S
Micromorphologic features of dentin in vitamin D-resistant rickets:correlation with clinical grading of severity.
In: Pediatr Dent (1989 Sep) 11(3):203-8
This study was a histological analysis of 20 primary teeth from 5 patients with 3 clinical grades of vitamin D-resistant rickets (VDRR). The results showed that the degree of globular dentin formation in the histological sections may be graded into Grades I-III in increasing order of severity. In Grade I, the amount of globular dentin was less than 50% of the total dentin thickness, and the interglobular spaces were small. By contrast, in Grade III severity, globular dentin extended throughout the entire thickness of dentin, and the interglobular spaces were large. In Grade II severity, the amount of globular dentin was more than half but did not involve the entire dentin thickness. These histologic grades of severity correlated directly with the clinical grades of the patients. In addition, the study found that lack of medical treatment in affected mothers might lead to globular dentin formation in the fetus in-utero. Conversely, adequate phosphate supplementation in a hypophosphatemic mother might prevent the formation of globular dentin in the fetus.
***REVUE DE STOMATOLOGIE ET DE CHIRURGIE MAXILLO-FACIALE****
89266600
Berdal A Cuisinier-Gleizes P Balmain N Thomasset M Brehier A Deffez JP Mathieu H
[The systemic environment and dental development. From the clinical to the molecular approach]
Environnement systemique et developpement dentaire. De la clinique a l'approche moleculaire.
In: Rev Stomatol Chir Maxillofac (1989) 90(2):111-4
(Published in French)
Clinical observation of patients with disordered phosphocalcium metabolism has demonstrated that dyschromia and/or dental dysplasias systematically accompany such disorders. A certain action of this steroid on dental buds has been demonstrated after analysis of the effects of experimental vitamin D deficiency in the rat: vitamin D would seem to control the behaviour of cells undergoing differentiation and also after this process is complete. Dentinogenesis and amelogenesis would appear principally to be affected. Two proteins, calbindins D-9K and -28K, may constitute the molecular mediators of this ameloblastic regulation.
Institutional address:
Unite 120 INSERM
Le Vesinet.