The XLH Network inc. -

***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.

**********ANNUAL NEW YORK ACADEMY 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 tothe 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.

<Amino Acid Sequence><Animal><Bone and Bones/PH><Bone Matrix/PH><Calcification, Physiologic/*><Calcium Oxalate/*ME><Cattle> <Dentin/PH><Durapatite/ME><Molecular Sequence Data><Rats> <Sialoglycoproteins/*PH><Support, U.S. Gov't, P.H.S.><

Hospital for Special Surgery

New York

New York 10021

USA.

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.

****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.

*****JOURNAL OF DENTAL RESEARCH*****

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

<Calcium, Dietary/TU> <Dentin/AB/CH/UL> <Hypophosphatemia, Familial/BL/DH/ME/PA <Phosphorus, Dietary/TU> <Animal> <Bone Density> <Calcium/BL> <Female> <Incisor> <Male> <Mandible/CH/PA> <Mice> <Mice, Inbred C57BL> <Mice, Inbred Strains> <Microscopy, Electron, Scanning> <Odontoblasts/PA> <Phosphorus/BL> <Support, Non-U.S. Gov't> <X-Ray Diffraction> <Medline File>

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.

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.

><Calcium Oxalate/*CH><Dentin/CH><Dentin Permeability><Human><Microscopy, Electron, Scanning><Molar, Third><Smear Layer/*>< X-Ray Diffraction>

Address

Department of Mineralogical Sciences

University of Bologna

Italy.

*****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

Canada.

**********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-Aug;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.

<Hypophosphatemia, Familial/DT/*PA> <Male> <Phosphates/AN/TU><Vitamin D/TU

ADDRESS

Institute of Dentistry

University of Oulu

Finland.

IS - 0022-0353

*****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.

*****PEDIATRIC DENTISTRY*****

91351904

McWhorter AG Seale NS

Department of Pediatric Dentistry, Baylor College of Dentistry,Dallas.

Prevalence of dental abscess in a population of children with vitamin D-resistant rickets.

Pediatric Dentistry 1991 Mar-Apr;13(2):91-6

A population of patients with vitamin D-resistant rickets whose present ages range from 4 to 22 years was examined to determine the prevalence of dental abscess associated with that condition. For those patients affected with abscesses in the primary dentition,four associated factors were examined: 1) the age at onset of the first abscess; 2) the tooth/teeth most commonly involved; 3) whether or not other teeth were involved over time; and 4) the order of occurrence of multiple abscesses. Six of 24 patients (25%) were affected with abscesses of the primary dentition; all had multiple abscesses. Males were more commonly involved than females. The sequence of involvement generally followed the pattern of tooth eruption; however, dental treatment in susceptible individuals shortened the time between eruption and abscess. Medication dose and measurement of radiographs were not reliable predictors of the occurrence of abscesses in this population; however, the results indicate that one abscess is a predictor of future abscesses for that patient.

*****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*****

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.

*****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

<Hypophosphatemia, Familial/ME/PA> <Tooth/CH/ME>

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.

**********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.

><Case Report><Child><Dental Caries/*CO><Dental Fistula/CO><Dental Pulp Cavity/AB> <Female><Human><Hypophosphatemia, Familial/*CO><

Review, Tutorial

ADDRESS

Department of Pediatric Dentistry

University of Illinois

Chicago.

*****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

<Hypophosphatemia, Familial/GE/ME/PA> <Linkage (Genetics)> <Mutation><Phosphates/BL> <Tooth/ME/PA> <X Chromosome><Adolescence> <Adult> <Dentin/ME> <Female> <Gene Expression> <Human><Kidney/ME> <Male> <Odontometry> <Sex Factors><Support, Non-U.S. Gov't> <Medline File>

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.

*****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.

> Animal> Crystallography> Dentin/AB/*PA> Disease Models, Animal> Female> Male> Mice> Mice, Inbred Strains> Phosphates/*BL> Tooth Abnormalities/GE/*PA> X Chromosome> X-Ray Diffraction

Address:

Department of Pedodontics

Osaka University Faculty of Dentistry

Japan.

*****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.

*****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

<Hypophosphatemia, Familial/BL/PA> <Tooth, Deciduous/PA> <Child> <Dentin/AN> <Female> <Human> <Hydroxyapatites> <Male> <Phosphates/BL> <Spectrophotometry, Infrared> <X-Ray Diffraction>

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.

***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.*****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.

> Adolescence> Adult> Female> Genes, Dominant/*> Human> Hypophosphatemia, Familial/*GE> Male> Phenotype> Support, Non-U.S. Gov't> Tooth Abnormalities/*ET> Tooth Diseases/*ET> X Chromosome/*

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.

>Calcium/AN> Child> Dental Enamel/AN/PA> Dentin/AN/PA> Electron Probe Microanalysis> Female> Human> Hypophosphatemia, Familial/GE/*PA> Male

> Microradiography> Phosphorus/AN> Tooth, deciduous/*AB/AN

Address

Osaka University Faculty of Dentistry

Japan.

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.

*****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.

*****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.

****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.

******JOURNAL OF PEDIATRICS******

81193960

Nikiforuk G Fraser D

The etiology of enamel hypoplasia: a unifying concept.

Journal of Pediatrics 1981 Jun;98(6):888-93

In a study of children with chronic disorders of calcium and phosphate homeostasis, enamel hypoplasia was found in hereditary vitamin D-dependency rickets and in hypoparathyroidism, conditions characterized by hypocalcemia, and was not found in X-linked hypophosphatemic rickets, a condition in which the plasma calcium concentration is normal. The occurrence of enamel hypoplasia bore no relation to the plasma phosphate concentration. Enamel hypoplasia has also been reported in other pediatric disorders in which hypocalcemia is a major sign (for example, vitamin D deficiency, prematurity, and neonatal tetany). The existence of enamel hypoplasia in a hypoparathyroid or rachitic patient, when correlated with the chronology of enamel mineralization, helps to establish the time of onset of hypocalcemia. The observations led us to the hypothesis that a low serum calcium concentration during enamel formation is a specific determinant of enamel hypoplasia. This hypothesis may be relevant to the etiology of linear enamel hypoplasia, an endemic lesion of primary teeth in children of many Third World countries that predisposes the teeth to dental caries.The hypothesis may therefore be relevant also in explaining the prevalence of caries in the primary teeth of children in many underdeveloped countries.

*****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

<Support, U.S. Gov't, Non-P.H.S.> <Tooth Diseases/GE>

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.

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.

><Animal><Calcitonin/*PD><Calcium/*ME><Parathyroid Hormones/*PD> <Propranolol/*PD><Rats><Tooth Germ/*ME>

**********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.

><Bone Diseases, Developmental/CO><Chromosome Abnormalities/CO><Dental Pulp Cavity/AB/PA><Dentin Dysplasia/CO><Dentinogenesis Imperfecta/CO> <Hypophosphatasia/CO><Hypophosphatemia, Familial/CO><Odontodysplasia/CO> <Phosphorus/BL><Pseudohypoparathyroidism/CO><Racial Stocks><Rickets/CO> <Support, U.S. Gov't, P.H.S.><Syndrome><Tooth Abnormalities/*PA>

********JOURNAL OF THE AMERICAN DENTAL ASSOCIATION*****

76095792

Cohen S Becker GL

Origin, diagnosis, and treatment of the dental manifestations of vitamin D-resistant rickets: review of the literature and report of case. [Review]

Journal of the American Dental Association 1976 Jan;92(1):120-9

Previous discussions center on early diagnosis, initial treatment,and follow-up therapy for the patient with vitamin D-resistant rickets. Both the medical and dental aspects of treatment for these patients has a long-range effect on the normal developmental patterns. Although treatment is begun at an early age, some rachitic skeletal effects such as minor bowing of the legs and bossing of the skull will invariably be noticed. In patients with controlled rickets the alveolar processes undergo normal development, with apparent normal dental eruption. The poor development and calcification of the alveolus seen in the untreated patient leads to loss of the lamina dura and periodontal ligament of the teeth. Patients with resistant rickets possess a functional dentition, although not without inherent defects. Various degrees of fracture and attrition of enamel can be seen, and hypoplasia of dentin is nearly a universal result. Defects extending to the dentinoenamel junction have been shown in repeated cases. Cementum, because of its close relationship with dentin calcification, also appears abnormal.Pulp tissue may undergo abberations of physiology in resistant rickets, although further work in this respect is needed. With respect to the possible dental pathoses seen in this disease, the dental history of the patient with resistant rickets discussed in this report showed that several of the deciduous teeth, possibly the mandibular left second premolar and right first molar, and definitely the maxillary right second premolar and canine and the mandibular left canine had all undergone pulpal degeneration of apparently unknown causation. In the maxillary right second premolar and the mandibular left canine, enamel fractures were clinically and radiographically apparent. However, the maxillary right canine originally had an acute abscess with no defects other than normal,minimal wear facets. No causative factor for its necrosis could be found. Overt enamel fractures in the maxillary right second premolar and the mandibular left canine may have led to microexposures of the pulp with subsequent bacterial pulpal contamination. Suppuration present in several of the pulps when first entered during endodontic treatment, as well as chronic fistulas in several areas, support the conclusion that contamination by some means does indeed occur.

*****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

<Hypophosphatemia, Familial/CO/PA> <Tooth Diseases/ET/RA><Adolescence> <Child> <Child, Preschool> <Human> <Periapical Abscess/ET>

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.