AbstractPatients with Vitamin D-resistant rickets have abnormal tooth morphology such as thin globular dentin and enlarged pulp horns that extend into the dentino-enamel junction. Invasion of the pulp by microorganisms and toxins is inevitable. The increased fibrotic content of the pulp, together with a reduced number of odontoblasts, decreases the response to pulp infection. The most important oral findings are characterized by spontaneous gingival and dental abscesses occuring without history of trauma or caries. Radiographic examinations revealed large pulp chambers, short roots, poorly defined lamina dura and hypoplastic alveolar ridge. These dental abscesses are common and therefore the extraction and pulpectomy are the treatment of choice. The purpose of this article is to report a case of Vitamin D-resistant rickets in a 5 year-old boy, describing the dental findings and the treatment to be performed in these cases.
INTRODUCTIONVitamin D-resistant rickets (VDRR), also known as hereditary or familial hypophosphatemia, is characterized by a metabolic disturbance which causes defective calcification of mineralized structures14. VDRR is well established genetically as an X-linked dominant metabolic disorder, that may be characterized by persistent hypophosphatemia and hyperphosphaturea associated with decreased renal tubular reabsorption of inorganic phosphates6,8. The prevalence rate is usually reported to be around 1:20,0004,12. In this condition, there is deficient mineralization of bone caused by a genetic defect in renal transepithelial transport of phosphate, which leads to a decrease in tubular reabsorption of phosphate and persistent hypophosphatemia. The features of rickets are the main systemic signs, but many children are not diagnosed until about 2-3 years of age. The metabolic disorder is treated with large doses of oral replacement of phosphate4,12. These anomalies lead to discordance between the production and the rate of mineralization of bone matrix, hence the accumulation of unmineralized matrix and poorly mineralized bone, causing as main clinical features severe body deformities, especially bowing of the legs, impaired growth and short stature. Radiologic findings usually include fractures, generalized osteopenia, growth failure, in some cases craniosynostosis may be present and arched or curve legs6,16. Dental findings that are often characteristic include dentin defects, unusually large pulp chambers and enlarged pulp horns, in some cases the enamel is hypoplastic11,14,16. These dental problems are more commonly associated with the primary than the permanent dentition6. The most common intraoral radiologic findings include large pulp chambers, short roots, poorly defined lamina dura and hypoplastic alveolar ridge16. On histologic analysis, the dentin exhibits large tubular clefts or lacunae and the enlarged pulp horns may extend beyond the dentino-enamel junction5,6. The poorly formed dentin and close proximity of the pulp to the tooth surface may lead to a rapid necrosis of the pulp with periapical complications, because the bacterial ingress to the pulp is being facilitated, occurring spontaneous dental abscess without history of trauma or caries6,14. The purpose of this article is to report a case of VDRR in a 5 year-old boy, describing dental findings and treatment.
CASE REPORTA 5 year-old boy was referred to the Pediatric Dentistry Clinic with the complaint of "a small ball that appeared in the mouth". During the anamnesis, the patient was diagnosed as having hypophosphatemic vitamin D-resistant rickets. The child was the third twin; however, the parents as well as the siblings, did not have the metabolic disorder. The medicines taken by the patient were calcitriol and phosphate supplements. He presented short stature and several skeletal abnormalities. Clinical examinations revealed fistula at the periapical region of primary maxillary left lateral incisor without caries or trauma (Figure 1). The patient presented complete primary dentition and none of the teeth examined showed evidence of caries (Figure 2A-B). Radiographic examinations included periapical, panoramic and occlusal views showing pulp chambers enlarged, with pulp horns extending to the dentino-enamel junction, poorly defined lamina dura and hypoplastic alveolar ridge (Figure 2C). The patient presented a large physiologic wear of the incisors, geographic tongue and primary mandibular right lateral incisor (#82) and canine (#83) with crown alteration (Figure 3A-B). There were areas of rarefaction around the apices of the primary maxillary right and left central incisor (#51,61), primary maxillary right and left lateral incisor (#52,62), primary maxillary right and left canine (#53,63) and primary maxillary right and left first molar (#54,64), primary mandibular right and left central incisor (#81,71) (Figure 4 and 5A-B).
Figure 2A-B The patient presented complete primary dentition and none of the teeth examined showed evidence of caries
Figure 3A-B Teeth #82 and #83 fused, clinical and periapical radiography
Figure 5A-B Periapical radiography showed pulp chambers enlarged with pulp horns extending to the dentino-enamel junctionInitially, two sections of management were performed. The treatment was divided into two phases: at first, the extraction of the teeth was performed: #51, 61, 81 and 71. At the second phase, endodontic treatment of the teeth: #52, 62, 53 and 63. These procedures were executed with local anesthesia and rubber dam isolation. The root canals were submitted to preparation with Kerr files and dressing with paramonoclorofenol (Biodinâmica LTDA, Brazil) for 48 hours. Canals were filled with zinc oxid-eugenol and iodoform paste and restored with resin glass ionomer cement (Vitremer, 3M/ESPE, USA). During the aforementioned treatment, primary mandibular right first molar (#84), primary maxillary right and left first molar (#54,64) and primary mandibular left second molar (#75) showed periapical fistula without evidence of caries or trauma in a short-term. These teeth were extracted. However, the child was constantly sick and did not attend the consultations. In the other teeth, the primary mandibular right second molar (#85), lateral incisor and canine (#82,83), primary maxillary right and left second molars (#55,65), primary mandibular left first molar and lateral incisor and canine (#74,73,72), the choice of treatment was to open the pulp chambers and make a dressing with formocresol (Biodinâmica LTDA, Brazil). After a 7-day period, the dressing with formocresol was removed and the root instrumentation was performed and filled with zinc oxid-eugenol and iodoform paste, afterwards the teeth were restored with resin glass ionomer cement (Vitremer, 3M/ESPE, USA) (Figure 6).
Figure 6 Panoramic radiography showed the final treatmentIn order to maintain the space of primary maxillary right and left second molars and primary mandibular right second molar, a fixed space-maintainer was made and cemented with resin modified glass ionomer cement (Rely X, 3M/ESPE, USA) (Figure 7A-B). The postoperative clinic course was uneventful and after six months of follow-up, the child did not show clinical abscesses.