Case report: dental treatment of a child with hypophosphataemic rickets.
Background: Hypophosphataemic rickets is an hereditary metabolic disease characterised by osseous and dental structural defects. The oral manifestations include highly frequent pulp infections as a result of enamel and dentinal defects. The pulp infections are multiple, spontaneous and can occur from an early age, becoming, in some cases, the first signs of the disease. An early preventive treatment is essential for a good oral health of these patients. Case report: The purpose of this case report was to illustrate the dental repercussions of hypophosphataemic rickets in a five-year-old child. Intraoral examination showed a complete primary dentition and two fistulae at the labial periapical region of teeth 51 and 61. Bitewing radiographs revealed multiple interproximal caries of the primary molars. Pulp chambers were enlarged, with pulp horns extending to the dentino-enamel junction. Treatment: Quadrant dentistry with rubber dam isolation was carried out. Pulpotomies were performed with ferric sulphate and reinforced zinc-oxide eugenol cement on the entry of the radicular canals. For all teeth, after pulpotomy, complete haemostasis was achieved, suggesting healthy pulps. Molars were restored with pre-formed metal crowns cemented with glass ionomer cement. For canines, after pulpotomy, a glass ionomer base and a composite resin was used. Follow-up: At six-month follow-up unsuccessful multiple pulpotomies (55, 75, 85, 74, and 63) were noted. Clinically there were abscesses on 55 and 63 and pulpectomies will now be needed, but the prognosis remains unclear
Key words: Hypophosphataemic Rickets; Pulpotomy; Primary Teeth
Albright and colleagues made one of the first descriptions of the hypophosphataemic rickets in 1937. Those authors described a clinical case of rickets, with hypophosphataemia and hyperphosphaturia resistant to normal doses of vitamin D, and classified this metabolic condition as inheritable X-linked hypophosphataemic rickets (XLHR). XLHR is also known as hereditary hypophosphataemia [Herbert, 1986], familial hypophosphataemia [Seow et al., 1995] and vitamin D-resistant rickets [Breen, 1986].
XLHR is considered the most frequent form of rickets in children and is characterised by familial occurrence, reduced serum phosphorous level and disturbed ossification that does not respond to physiological doses of vitamin D [Abe et al., 1988]. The usual mode of transmission is X-linked dominant, and the males tend to show a greater penetrance of disease, as females carry a normal gene on the X chromosome [Fadavi and Rowold, 1990; Seow et al., 1995; Murayama et al., 2000; Shroff et al., 2002].
In XLHR, the inorganic phosphate re-absorption in the intestine, as well as in the proximal renal tubules, is diminished leading to a hypophosphataemia and hyperphosphaturia. The main effect of hypophosphataemia is an impaired mineralization of teeth, bone and cartilage [Breen, 1986; Murayama et al., 2000; Pereira et al., 2004]. The medical treatment is based on supplementation with high doses of oral neutral phosphate, complemented with supplements of vitamin D or analogues [Rakocz et al., 1982].
In patients without a familial history of rickets, the first clinical signs can be missed for two years after birth, becoming noticeable only when the child begins to walk, with a delay in the development and osseous deformities with lateral bowing of the legs [Fadavi and Rowold, 1990]. Other clinical findings present in the majority of these patients include short stature, thoracic and cranial osseous deformities [Breen, 1986; Fadavi and Rowold, 1990; Murayama et al., 2000; Pereira et al., 2004].
Although XLHR has been recognized since the 1930s, it was not until 1960, that Harris and Sullivan  reported the dental abnormalities characteristic of the disease. Other authors confirmed the dental manifestations in both primary and permanent dentition: enamel hypoplasia, hypocalcified and interglobular dentine and a widened preventive layer [Fadavi and Rowold, 1990; Larmas et al., 1991; Seow et al., 1995; Kawakami and Takano-Yamamoto, 1997; Murayama et al., 2000; Pereira et al., 2004]. The radicular and pulp chambers are characteristically enlarged, with pulp horns extending to the dentino-enamel junction [Fadavi and Rowold, 1990; Larmas et al., 1991; Kawakami and TakanoYamamoto, 1997; Shroff et al., 2002; Pereira et al., 2004].
Dental aspects. The clinical repercussions of an abnormal dental histology are typical: pulp necrosis and spontaneous dental abscesses, which occur without any history of caries or trauma [Fadavi and Rowold, 1990; Larmas et al., 1991; Seow et al., 1995; Murayama et al., 2000; Pereira et al., 2004]. Many of these authors also believed that dental infections were initiated with bacterial invasion through enamel micro-fractures that extended to the pulp. In many instances, minor caries or physiological attrition can remove the enamel and allow microorganism's access to the pulp, leading to healthy appearing teeth to "spontaneously" abscess. Soni and Marks  suggested the presence of a dentinogenesis defect, but Abe et al.  observed reparative dentine in response to attrition and a normal odontoblastic function. These authors also showed that the fragility of enamel was due to its poor mineralization.
Other oral pathologies in XLHR reported in the literature include dental abrasion and periodontal disease [Pereira et al., 2004], absent or poorly defined lamina dura [Larmas et al., 1991], taurodontism and ectopic eruption of permanent canines [Seow et al., 1995]. According to Seow , a delayed eruption may occur in some patients, but it may be originated by local factors, such as a premature loss of the primary teeth.
Different clinical approaches have been proposed for the dental management of patients with XLHR: Breen  and Rakocz et al.  consider that fissure sealants are contraindicated because they will not prevent the wear of the cusp tips. Additionally, the potential risk of acid penetration through enamel cracks may endanger the pulpal integrity.
McWhorter and Seale  reported that 25% of patients with XLHR manifested abscesses in the primary dentition. As a prediction of the occurrence of infections could not be made, they recommended an aggressive preventive dental treatment of all posterior teeth, with pulpotomies and preformed metal crowns (PMC). The same approach was recommended by other authors [Fadavi and Rowold, 1990].
Gardner et al.  and later Shroff et al.  reported a failure of formocresol pulpotomies in XLHR, possibly related with a lack of reparative dentine and an unpredictable reaction of the pulp to mummifying procedure. The first authors believed that the repeated failure was a reflection of a non-healthy pulp and there was insufficient evidence to suggest that prophylactic pulpotomies are beneficial in preserving the primary dentition. Rakocz et al.  suggested a more radical approach, that is, zinc oxide-eugenol pulpectomy as elective pulp therapy, and coverage with PMC in molars and polycarbonate or composite resins (strip) crowns in anterior teeth. Other authors reported that the PMC should be performed with a minimal tooth preparation, to avoid pulpal exposure [Breen, 1986; Herbert, 1986]. There have been no case reports of hypophosphataemic children treated with ferric sulphate pulpotomies and it is unknown whether there is any long-term success of this treatment.
The importance of hypophosphataemic rickets in dentistry is based on two parameters: 1) the dental manifestations commonly represent the first clinical sign of the disease and, 2) the common presence of abscesses in teeth without history of caries or trauma implies special measures of oral health prevention.
Patient. A 5-yr-old male child, with hypophosphataemic rickets, presented with a two-year delay in his osseous maturation, a low percentile development, short stature and bowing of legs. He was receiving supplements of neutral phosphate daily. His mother reported that the child had a delayed eruption of the primary teeth, with the mandibular incisors not erupting until at about 14 months of age.
Diagnosis. The first appointment was motivated by the presence of "abscessed teeth". Intraoral examination showed a complete primary dentition and two fistulae at the labial periapical region of teeth 51 and 61; the 61 was caries free and without history of trauma. A radiograph showed a distal radiolucency on 51, compatible with dental caries (Figure 1 a). Antibiotic therapy was initiated and both teeth were extracted after one week.
[FIGURE 1 OMITTED]
Bitewing radiographs revealed multiple interproximal caries of the primary molars, confined to the enamel. The pulp chambers were enlarged, with pulp horns extending to the dentino-enamel junction (Figure 1 b). At this time, a treatment plan for the carious lesions was implemented with a periodic review preventive program, which included dietary advice, oral hygiene instructions and topical fluoride rinses, to decrease the caries risk.
Ongoing care. Despite recommendations, the patient only returned to the clinic one year later, with fistulae on both 52 and 62 and on 71 and 81. Under antibiotic coverage, these teeth were extracted. One month later, the child presented again with a complaint of pain in the third quadrant (71 to 75) and become increasingly uncooperative. An emergency pulpotomy was carried out and full coverage with a preformed metal crown (PMC) on 74. It was evident at this time that some form of aggressive prophylactic treatment would now be necessary to prevent further abscesses of teeth. It was decided to perform elective pulpotomies on all molars and canines, and because of the rapid progression of the lesions, the number of teeth involved, and the risk of new painful episodes, this second phase of treatment was performed under general anaesthesia (GA) as an out-patient.
[FIGURE 2 OMITTED]
Figures 3a and b, show clinical views at the beginning of the rehabilitation and post-operatively with remission of the fistulae associated to maxillary incisors. It can be seen that there was apparently superficial caries on labial surface of maxillary canines (Fig 3b).
[FIGURE 3 OMITTED]
The dental treatments were performed by quadrants and with isolation with rubber dam. Pulpotomies were performed with 15.5% solution of ferric sulphate (Astringedent[R]) and reinforced zinc-oxide eugenol cement on the entry of the radicular canals (IRMR). For all teeth, after ferric sulphate pulpotomy, complete haemostasis was achieved, suggesting healthy pulps. Molars were prepared for full coverage with PMC, and cemented with glass ionomer (Pro-Lock Band Cement[R]). For canines, after pulpotomy, a glass ionomer base (Vitrebond[R]) to separate the zinc-oxide eugenol from a composite resin (Z1 00R, 3M) was used.
At 3 months follow-up, there were no clinical or radiological signs of pulp infections; teeth presented without mobility, painless and without fistulae (Figure 4a). The six-month follow-up (Figure 4b), however, revealed the presence of unsuccessful multiple pulpotomies (55, 75, 85, 74, and 63). Clinically there were abscesses on 55 and 63 (Figure 5a and b). It will now be planned to perform zinc-oxide eugenol pulpectomies, but the prognosis remains unclear. Oral care support for the permanent dentition will be implemented, as soon as possible.
[FIGURE 4 OMITTED]
The pulpotomy is based on the rationale that the radicular pulp tissue is healthy and capable of healing after amputation of the coronal pulp (Fuks, 1991). The most commonly used pulp dressing material is formocresol (Primosch et al, 1997), but its safety has been questioned by some authors, who feel that this agent is potentially mutagenic (Myers et al, 1981, 1983). Ferric sulphate is deemed to be a safer haemostatic agent, with comparable outcomes to formocresol pulpotomy (Smith et al, 2000; Fuks et al, 2006)
In this case report, we had achieved a better result than previous authors, who performed formocresol pulpotomies. While some of the treated teeth developed abscesses, others have been successful at six-month follow-up. We believe that more research is needed about the prognosis of ferric sulphate pulpotomies and the selection of the best pulpotomy agent on the children affected by this syndrome. It may be that the ferric sulphate is a better medicament in these patients, but it will be interesting to develop clinical studies with long-term follow up, and with this treatment regimen, in order to achieve more predictable results.
Hypophosphataemic rickets leads to severe repercussions on oral health and a previous knowledge of the potential risk of pulp infections is necessary, to make possible a successful preventive oral health program. In many cases, the more successful preventive protocol corresponds to pulp therapy procedures and full coverage with preformed metal steel crowns. The literature shows that the success rate of pulp therapy is lower than in healthy children, and so it is crucial that there is a long term follow-up of all treatments. The family of the child must know that treatment plan may well have to be changed with time and the extraction of previously treated teeth may be necessary.
Abe K, Ooshima T, Lily TS, Yasufuku Y, Sobue S. Structural deformities of deciduous teeth in patients with hypophosphatemic vitamin D-resistant rickets. Oral Sung Oral Med Oral Pathol 1988;65(2):191-8.
Albright F, Butler AM, Bloomberg E. Rickets resistant to vitamin D therapy. Am J Dis Child 1937;54:529-47.
Breen GH. Prophylactic dental treatment for a patient with vitamin D-resistant rickets: report of case. J Dent Child 1986;53(1):38-43.
Fadavi S, Rowold E. Familial hypophosphatemic vitamin D-resistant rickets: review of the literature and report of case. J Dent Child 1990;57(3):212-5.
Fuks AB, Eidelman E. Pulp therapy in the primary dentition. Curr Opin Dent 1991;1:556-563.
Fuks AB, Holan G, Davis JIM, Eidelman E. Ferric sulfate vs dilute formocresol in pulpotomized primary molars: long-term follow-up. Pediatr Dent 1997;19:327-330.
Fuks AB, Papgianoulis L. Pulpotomy in primary teeth: review of the literature according to standardized assessment criteria. Europ Archs Paediatr Dent 2006, 7:64-72
Gardner DE, Davis WB, Prescott GH. Hereditary Hypophosphatemia. J Dent Child 1969; 36:199-216.
Harris R, Sullivan HR. Dental sequelae in deciduous dentition in vitamin D resistant rickets. Aust Dent J 1960;5:200-3.
Herbert FL. Hereditary hypophosphatemia rickets: an important awareness for dentists. J Dent Child 1986;53(3):223-6.
Kawakami M, Takano-Yamamoto T. Orthodontic treatment of a patient with hypophosphatemic vitamin-D resistant rickets. J Dent Child 1997;64(6):395-9.
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. J Dent Child 1991;58(4):328-34.
McWhorter AG, Seale NS. Prevalence of dental abscess in a population with vitamin D-resistant rickets. Pediatr Dent 1991;13(2):91-6.
Murayama T, Iwatsubo R, Akiyama S, Amano A, Morisaki I. Familial hypophosphatemic vitamin D-resistant rickets: dental findings and histologic study of teeth. Oral Sung Oral Med Oral Pathol Oral Radiol Endod 2000;90(3):310-6.
Myers DR, Pashley DH, Whittford GM, et al. The acute toxicity of high doses of systemically administered formocresol in dogs. Pediatr Dent 1981;3:37-41.
Myers DR, Pashley DH, Whittford GM, et al. Tissue changes induced by the absorption of formocresol from pulpotomy sites in dogs. Pediatr Dent 1983;5:6-8.
Pereira CM, Andrade CR, Vargas PA et al. Dental alterations associated with X-linked hypophosphatemic rickets. J Endod 2004;30(4):241-5.
Primosch R, Glomb T Jerrell R. Primary tooth pulp therapy as taught in pediatric dental programs in the United States. Pediatr Dent 1997;19:118-122.
Rakocz M, Keating J, Johnson R. Management of the primary dentition in vitamin D-resistant rickets. Oral Surg Oral Med Oral Pathol 1982;54(2):166-71.
Seow WK, Needleman HL, Holm IA. Effect of familial hypophosphatemic rickets on dental development: a controlled, longitudinal study. Pediatr Dent 1995;17(5):346-350.
Shroff DV, McWhorter AG, Seale NS. Evaluation of aggressive pulp therapy in a population of vitamin D-resistant rickets patients: a follow-up of 4 cases. Pediatr Dent 2002;24(4):347-9.
Smith NIL, Seale NS, Nunn ME. Ferric sulfate pulpotomy in primary molars: a retrospective study. Pediatr Dent 2000;22:192-199.
Soni NN, Marks SC. Microradiographic and polarized-light study of dental tissues. Oral Sung Oral Med Oral Pathol 1967;23:755-62.
A. Coelho, P. Marques, J.P. Canta. Dept. Paediatric Dentistry, Lisbon Dental School, Lisbon, Portugal
Postal address: Dr. Ana Coelho. Clinica Joao Pedro Canta, Trav. do Matadouro, no 11,1oL, Portugal.
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|Author:||Coelho, A.; Marques, P.; Canta , J.P.|
|Publication:||European Archives of Paediatric Dentistry|
|Article Type:||Disease/Disorder overview|
|Date:||Jan 1, 2007|
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