PEDIATRIC DENTISTRY/Copyright © 1986 byThe American Academy of Pediatric Dentistry

Volume 8 Number 3

The spectrum of dental manifestations in vitaminD-resistant rickets: implications for management

W. Kim Seow, BDS, MDSc, FRACDS S.C. Latham, MBBS, FRACP

AbstractVitamin D-resistant rickets (VDRR), usually inherited in

X-linked dominant manner, is the most common type of ricketsin developed countries today. This analysis of 13 patients affectedby the disease indicates that dental manifestations occur in a widespectrum of severity which is determined by several factors in-cluding heredity, sex, and medical treatment. The spectrum ofseverity of dental manifestations can be classified into Grades I-III in order of increasing severity. Grade I severity includes nearnormal dentition while Grade II indicates involvement of only afew teeth. Grade III includes greatly enlarged pulp chambers,multiple dental abscesses, and poorly calcified dentin. Strategiesfor the prevention of dental abscesses in each grade of severityshould be used appropriately.

The most common form of rickets in developed

countries today is an inherited form of rickets knownas vitamin D-resistant rickets (VDRR).1 This condi-tion, first described by Albright et al., 2 also is knownby various other names such as familial hypophos-phatemia, vitamin D-refractory rickets, and phos-phate diabetes. The disease usually is inherited in anX-linked dominant manner,3 with an affected malepassing the defective gene to all his daughters andnone of his sons. In contrast, an affected female willpass the gene to half of the daughters and half of thesons.

The pathogenesis of VDRR results from a selectivedisorder of transepithelial transport of phosphate inthe kidney, leading to decreased tubular reabsorp-tion of phosphate and persistent hypophosphate-mia.4 The low levels of serum phosphate lead to de-fective calcification, with signs and symptoms ofrickets often appearing at about 8-10 months of age.These signs include lateral bowing of the legs, fron-tal bossing, enlargement of the costochondral junc-tions, scoliosis, and lordosis. Medical management of

VDRR consists of phosphate replacement togetherwith vitamin D given usually in the form of calci-triol.

The dental manifestations of VDRR are quite char-acteristic, with multiple "’spontaneous" dental ab-scesses being reported most often, s-is These abscessesresult from pulp exposures which occur easily dueto the large pulp chambers usually evident in thedental radiographs of these patients. Histologicalstudies often show abnormal dentin calcification withlarge calcospherities and tubular defects extendingclose to the dentino-enamel junction.5-s

Although previous studies on patients with VDRRhave described the above dental manifestations, littleemphasis has been placed on the prevention of den-tal abscesses. In addition, although it has been re-ported that hypophosphatemia occurs in varying de-grees of severity, it is not known whether dentalmanifestations are affected accordingly.

The authors studied several patients from differentfamilies with confirmed diagnoses of VDRR to de-termine the spectrum of dental manifestations of thedisease and the factors associated with these varia-tions. The objective of the study was to provideguidelines in the prevention of dental abscesseswhich may be a constant problem in affected pa-tients.

Spectrum of Dental ManifestationsThirteen patients from 6 different families were

studied. A summary of the characteristics of thesepatients are shown in Table 1. Based on dental man-ifestations and the need for treatment and preven-tion of dental abscesses, the patients can be dividedinto 3 main grades as follows.

Grade I is comprised of patients who show mini-mal or no dental manifestations of VDRR. These pa-tients require only routine dental care and preven-

PEDIATRIC DENTISTRY: September 1986/Vol. 8 No. 3 245

Q-rO lo

JI iiiii

f Affected Female

O Normal Female

M

Affected Male

Normal Male

Adopted

FIG 1. Family pedigree of a female (Case 12) affected byVDRR, showing typical transmission of the disease in anX-linked dominant manner. Arrow shows proband.

tive measures. Seven patients in the series can becategorized into this group (Cases 6-13).

Grade II patients are those who show moderatedental manifestations of the disease, only a few teethare involved, and the prophylactic procedures re-quired are moderate. Four patients in the series canbe placed into this group (Cases 3-5).

Grade III is comprised of patients who show severedental manifestations of the disease and require ex-tensive treatment and aggressive prophylactic mea-sures to prevent the development of dental abscess-es. Two patients in the series can be placed into thisgroup (Cases 1 and 2).

Representative cases of each of the above classesare discussed.

Illustrative CasesGrade I (Case 12)

This female patient was 13 years old upon referralto the University Dental School. She was about 9months old when VDRR was diagnosed and treat-ment with phosphate and calcitriol started. She in-herited the disease from her mother (Case 11). Anolder sibling (Case 13) also was affected. The familypedigree chart shown in Fig 1 reveals typical trans-mission of the disease in an X-linked dominant man-ner.

At the time of dental examination, apart from ashort stature (height 130.5 cm, 3rd percentile) andslight bowing of the legs, she showed minimal skel-etal signs of rickets. Clinical examination revealedall permanent teeth except third molars were erupt-ed. No caries or periodontal abnormalities were de-tected, but the maxillary right permanent molarshowed enamel hypoplasia. No dental abscesses werenoted and there was no history of any abscesses in

<yFIG 2. Bite-wing radiographs of a female (Case 12) affect-ed by VDRR. The dental manifestations are of Grade I se-verity with near normal calcification of the teeth. Notenormal sizes of the pulp chambers.

the primary dentition. Radiographic examination re-vealed normal calcification of enamel and dentinewith the pulp chambers fairly normal in appearance(Fig 2). As the teeth were essentially normal, no pro-phylactic measures for dental abscesses were re-quired. However, fissure sealants were placed onposterior teeth as routine preventive procedures fordental caries.

The patient's sibling (Case 13) showed essentiallysimilar clinical and radiographic features, with min-imal dental signs of VDRR. Of interest, too, is thefact that the mother (Case 11) also exhibited minimalsigns of the condition and had no history of dentalabscesses despite moderate skeletal manifestations ofthe disease.

Grade II (Case 5)This female patient was referred to the Dental

School at age 13 years. She was diagnosed as havingVDRR at the age of 18 months and had been on phos-phate and calcitriol therapy continually. She inher-ited the disease from her mother (Case 10). Herbrother, the only sibling, was unaffected. The moth-er, who was the first-known member of the familywith the condition, was diagnosed herself only a fewyears previously. At the time of dental examinationskeletal manifestations of rickets were obvious—bowing of the legs, frontal bossing, and short stature(height 124.8 cm, < 3rd percentile).

At the time of dental examination, all her perma-

I

FIG 3. Bite-wing radiographs of a female (Case 5) withVDRR. The dental manifestations are of Grade II severitywith moderate enlargement of the pulp chambers.

246 VITAMIN D-RESISTANT RICKETS: Seow and Latham

FIG 4. Bite-wing radiographs of affected mother of Case5 taken at initial examination. Although she has VDRR,the dental manifestations are minimal. The pulp chambersof the teeth appear normal and no abscesses have devel-oped.

nent teeth except the maxillary canines and thirdmolars were erupted. Apart from hypoplasia of themaxillary right central incisor, no abnormalities weredetected intraorally. Radiographic examination of theteeth revealed enlarged pulp chambers of all per-manent teeth (Fig 3).

Clinical history confirms that Case 5 was affectedto a lesser degree than Case 1. Although there was ahistory of 3 "spontaneous" dental abscesses of theprimary teeth at the age of 8-9 years, the patient hadnot experienced an abscess of the permanent teethby 13 years.

Although this patient was less severely affectedcompared to Case 1, she still required prophylacticmeasures to prevent abscesses in predisposed teeth.In this case, occlusal coverage with acid-etched com-posite resins probably would suffice.

It is interesting to compare this patient with hermother from whom she inherited the condition. Themother had no history of dental abscesses and radio-graphs (Fig 4) show no abnormalities except for car-ies. The pulp chambers appeared normal and in spiteof the deep occlusal caries on the left mandibularfirst molar, no apparent abscess has developed.

Grade III (Case 1)

The patient, a 10-year-old male, was referred to theUniversity Dental School by his private practitionerat the age of 4 years because of multiple "sponta-neous" dental abscesses. There was no family historyof rickets. The patient was referred to a pediatrician.He was given vitamin D and oral phosphate supple-mentation beginning at about age 7. When the pa-tient first was seen by one of the authors (WKS) atage 9, he showed skeletal signs of rickets with bow-ing of the legs and frontal bossing of the skull. Hisheight was 132 cm (25th percentile) and he weighed38 kg (90th percentile).

All immediate family members were healthy andthe mother's medical history proved negative. It was

FIG 5. Periapical radiographs of the maxillary and man-dibular anterior teeth of a male (Case 1) taken at initialexamination. Note enlarged pulp chambers and periapicalradiolucencies associated with the incisor teeth.

concluded that the patient's disease may be the resultof a fresh genetic mutation.

When the patient first presented to the DentalSchool at the age of 4 years, all his primary incisorsshowed chronic draining abscesses. The teeth werenot carious and there was no history of trauma. Ra-diographs showed extremely large pulp chambers andpoorly calcified dentin (Fig 5). Histologic studies ofthe extracted teeth revealed large quantities of inter-globular dentin and extensions of pulp chambers intothe incisal edges of the teeth (Fig 6).

FIG 6. Section of amandibular primaryincisor from Case 1.Note the large size ofpulp chamber, poorlycalcified dentin (in-terglobular dentin),and extensions of thepulp chambers intothe incisal edges ofthe teeth.

The abscessed incisors were extracted soon afterthe initial examination. On subsequent visits, acid-etched composite resins were placed over the occlu-sal surfaces of the remaining primary teeth in anattempt to prevent further pulp exposures and ab-

PEDIATRIC DENTISTRY: September 1986/Vol. 8 No. 3 247

scesses. These resin caps were checked and adjustedregularly. However, in spite of this prophylactic pro-cedure, all the remaining primary teeth subsequent-ly became abscessed and required either extractionor endodontic treatment.

When the patient was seen by one of the authors(WKS) at 9 years of age, it was decided to use moreaggressive methods to prevent abscesses in the per-manent dentition. As soon as the first permanent mo-lars erupted, the occlusal surfaces were capped withacid-etched composite resins. When the teeth erupt-ed sufficiently, it was decided to cap them with stain-less steel crowns. Because of the large pulp chambers(Fig 7) there was grave danger of pulp exposures ifroutine tooth preparation was undertaken. Thisproblem was overcome by first placing separatingelastics interproximally to open up contact areas be-tween the teeth,16 thus reducing the need for proxi-mal reduction. Occlusal reduction was achieved byreducing the occlusal composite resin caps placedearlier. Prior to cementation of the stainless steelcrowns, any enamel not covered by the compositeresin was lined with calcium hydroxide before ce-mentation with zinc phosphate cement.

When the permanent incisors erupted, the deci-sion as to whether to cap these teeth had to be made.As the maxillary and mandibular incisors were con-tacting only minimally, it was decided that wear onthese teeth would be slight and the need for protec-tion not great. However, the lower right lateral in-cisor subsequently became abscessed and endodontictherapy was instituted. This forced the authors toreview the decision not to cap the incisors and onlater visits, the incisal edges of these teeth were pro-tected with acid-etched composite resins.

At the time of writing, the first premolars were inthe early stages of eruption. A plan of treatment sim-ilar to that for the first permanent molars was sug-gested and acid-etched composite resins were usedto cap the occlusal surfaces of the first premolars thatemerged. Stainless steel crowns for these teeth areplanned as soon as the teeth have erupted into oc-clusion.

When the patient reaches adulthood, the stainlesssteel crowns should be replaced with full gold orporcelain bonded-to-gold crowns to increase fit andmarginal adaptability.

DiscussionThis study of 13 patients with VDRR from several

families illustrates the wide range of dental manifes-tations that are seen in this condition. These patientscan be divided into 3 main grades according to theseverity of dental signs: Grade I patients have mini-mal dental signs of the disease: Grade II patients usu-

FIG 7. Bite-wing radiographs of Case 1 taken at age 10years. Note Grade III severity of dental manifestations withenlarged pulp chambers and abnormally calcified dentin.

ally show involvement of a few teeth only; and GradeIII patients have severe dental manifestations suchas multiple dental abscesses and grossly enlargedpulp chambers.

There are various factors which can account for thewide spectrum of dental manifestations in VDRR.First, genetic factors may play an important role indetermining the severity of disease. It is apparentfrom this study that the severity of dental manifes-tations is similar within each family. For example, in1 family (Cases 11-13), both the female patients andtheir affected mother show only minimal dental signsof VDRR. In another family (Cases 5 and 10), bothaffected mother and daughter exhibited mild dentalmanifestations of the disease. It is likely that VDRRis inherited in several different forms varying in se-verity, with each affected family showing similar se-verity among its members.

Within each affected family, individual variationsmay arise. An important factor is sex of the patient.Females tend to show less disease than males as ex-pected of an X-linked trait. In females, partial pro-tection is obtained from the presence of a normal Xchromosome in addition to the X chromosome car-rying the abnormal gene. Also, other factors such ashormones may influence the severity of disease inaffected females. For example, it had been shown thatthere is no consistent correlation between the sever-ity of hypophosphatemia and the severity of bonedisease in females.3 This present study, too, showsthat dental signs are less severe in females. Out of 9females, 7 can be classified into the group showingmild dental manifestations (Grade I), while the other2 belonged to the group with moderate dental man-ifestations (Grade II). On the other hand, the 2 chil-dren showing the most severe dental manifestations(Grade III) are both males (Cases 1 and 2). Anothermale patient (Case 3) showed moderate dental find-ings while the fourth male patient (Case 9) had nohistory of dental abscesses and no increased sizes ofthe pulp chambers. However, because the latter pa-tient was only 5 years of age at the time of dentalexamination, it is difficult to determine the extent ofinvolvement of the permanent teeth. Pliskin andcolleagues9 reported a case of VDRR in whom only

248 VITAMIN D-RESISTANT RICKETS: Seow and Latham

Table 1. Characteristics of 13 Patients with Vitamin D-Resistant Rickets

Case Sex

Age at Dental Age of DiagnosisExamination and Start of

(years) Medical Treatment

No. of Abscessed TeethIncreased Size Hypoplasia

Primary~Permanent of Pulp Chambers of Teeth

1. MG M 10 4.5 yr2. SS M 7 2 yr3. VB M 25 2 yr4. SB F 32 2-3 yr5. NS F 13 18 mo6. JS F 25 <12 mo7. KB F 9 9 mo8. AB F 2 9 mo9. MB M 5 9 mo

10. WS F 33 28 yr11. JB F 35 3 yr12. CB F 13 9 mo13. TB F 14 9 mo

20 1 +++ +16 3 +++ -? 2 ++ -? 7 + +3 0 + +? 1 - -0 0 - +0 -- ? -0 -- + -? 0 - -? 0 + +0 0 - +0 0 - -

the permanent dentition showed obvious clinicalmanifestations.

Medical therapy received by the patients may in-fluence the severity of dental manifestations. Oralsupplementation of inorganic phosphate to replacethe abnormal renal losses of phosphate is the usualmethod of treatment in VDRR. In addition, vitaminD in the form of calcitriol also is given to preventphosphaturia and hypercalcemia which may resultfrom phosphate loading. In children with knownfamily histories of the condition, diagnosis usuallyis made soon after birth. However, phosphate andvitamin D supplementation is not often given untilat least after 9 months of age. This is because the lowglomerular filtration rate in early infancy may pre-vent excessive losses of phosphate, 1 thus reducingthe need for early phosphate supplementation. Inaddition, constant monitoring of serum levels is vitalin vitamin D supplementation and repeated bloodsampling is not feasible in the very young infant.

Oral supplementary phosphate and calcitriolshould improve dental calcification and prevent ab-scesses. However, because many patients are not di-agnosed and treated until after 2 years of age, theentire primary dentition and permanent incisors andfirst molars do not receive the beneficial effects ofmedical therapy, and are at greatest risk for devel-oping dental abscesses. In this series, the 2 patients(Cases 1 and 2) with the greatest number of abscesseswere both diagnosed and treated only after 2 years

of age; in both cases, the entire primary dentitionbecame abscessed. In contrast, another male patient

(Case 9) who was diagnosed and treated at a fewmonths of age still has not developed any abscesses

of the primary teeth and the pulps of his teeth ap-peared fairly normal on radiographs.

The results of this study (Table 1) indicate thatwith the exception of a mildly affected female (Case10) who was not diagnosed until 28 years of age, the

earlier the institution of medical therapy, the lesssevere the dental manifestations. Further longitudi-nal clinical as well as histological studies on teethneed to be performed to establish the importance ofmedical therapy on dental calcification in VDRR.

Prevention of dental abscesses is an important aimin dental management of VDRR. Even minimal wearof the teeth can result in pulp exposures and protec-tion of functional tooth surfaces should be consid-ered. The need for such prophylactic coverage varieswith the severity of dental manifestations.

Besides prophylactic coverage to prevent occlusalwear, routine preventive care for dental caries is ex-tremely important as minimal caries can lead to pulpexposures. Fluoride therapy, dietary advice, and oralhygiene therapy should be given regularly.

Besides prophylactic treatment, control of existinginfection is important in the dental management ofthe patient with VDRR. Most clinical studies reportsuccess with routine endodontic procedures for ab-scessed teeth in VDRR. However, the thin and poor-ly calcified dentin walls of the root canals do notallow excessive instrumentation and care has to betaken to prevent perforation and root fracture. Also,if abscessed primary teeth are extracted, consider-ations must be given to space maintenance.

ConclusionsThe dental manifestations seen in patients with

VDRR appear in a spectrum of severity, ranging fromthe very severe, with involvement of nearly the en-tire dentition, to the very mild with normal appear-ance of the teeth. Effective strategies for the preven-tion of dental abscesses are available and should beemployed to suit each individual patient’s needs.

Dr. Seow is a pediatric dentistry lecturer, University of Queens-

land, and Dr. Latham is deputy medical superintendent, Royal

Children’s Hospital, Herston, Australia. Reprint requests should

PEDIATRIC DENTISTRY: September 1986/Vol. 8 No. 3 249

be sent to: Dr. W. Kim Scow, Dept. of Social and Preventive Den-tistry, University of Queensland, Turbot St., Brisbane, Australia4000.

I. Harrison HE, Harrison HC, Lifshitz F, Johnson AD: Growthdisturbance in hereditary hypophosphatemia. Am J Dis Child112:290-97, 1966.

2. Albright F, Butler AM, Bloomberg E: Rickets resistant to vi-tamin D therapy. Am J Dis Child 59:529-47, 1937.

3. Fraser D, Scriver CR: Familial forms of vitamin D-resistantrickets revisited. X-lir~ked hypophosphatemia and autosomalrecessive vitamin D dependency. Am ] Clin Nutr 29:1315-29,1976.

4. Glorieux F, Scriver CR: Loss of a parathyroid hormone-sensi-tive component of phosphate transport in X-linked hypo-phosphatemia. Science 175:997-1000, 1972.

5. Harris R, Sullivan HR: Dental sequelae in deciduous dentitionin vitamin D-resistant rickets. Case report. Aust Dent J 5:200-203, 1960.

6. Marks SC, Lindahl RL, Bawden JW: Dental and cephalometricfindings in vitamin D-resistant rickets. J Dent Child 32:259-65, 1965.

7. Archard HO, Witkop CJ: Hereditary hypophosphatemia (vi-tamin D-resistant rickets) presenting primary dental manifes-tations. Oral Surg 22:184-93, 1966.

8. Via WF: Spontaneous degeneration of the dental pulp associ-ated with phosphate diabetes. Oral Surg 24:623-28, 1967.

9. Pliskin ME, Brown AM, Baden EE, Kimball HG: Vitamin D-re-sistant rickets of young adult patient. A review and case re-port. J Oral Med 30:77-80, 1975.

10. Gardner DE, Davis WB, Prescott GH: Hereditary hypophos-phatemia. J Dent Child 36:199-216, 1969.

11. Cohen S, Becker GL: Origin, diagnosis, and treatment of thedental manifestations of vitamin D-resistant rickets: review ofthe literature and report of a case. J Am Dent Assoc 92:120-29, 1976.

12. Vasilakis GJ, Nygaard VK, DiPalma DM: Vitamin D-resistantrickets. A review and case report of an adolescent boy with ahistory of dental problems. J Oral Med 35:19-26, 1980.

13. Gallo LG, Merle SG: Spontaneous dental abscesses in vitaminD-resistant rickets: report of a case. J Dent Child 46:327-29,1979.

14. Tulloch EN, Andrews FFH: The association of dental abscesseswith vitamin D-resistant rickets. Br Dent J 154:136-38, 1983.

15. Scow WK: X-linked hypophosphataemic vitamin D-resistantrickets. Aust Dent J 29:371-77, 1984.

16. Scow WK: The application of tooth separation in clinical pe-dodontics. J Dent Child 51:428-30, 1984.

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250 VITAMIN D-RESISTANT RICKETS: Scow and Latham