X-ray microanalysis of teeth from healthy patients and patients with familial hypophosphatemia

Dental manifestations and treatment of hypophosphatemic rickets: A case report and review of literature

BACKGROUND

The treatment and management of patients suffering from hypophosphatemic rickets (HR) remain a major challenge for dental practitioners and affected patients.

OBJECTIVES

To report a case of HR presenting with specific dental findings and to review the dental manifestations and treatment of HR patients.

METHODS

Case: A 32-year-old male presented with multiple dental abscesses and short stature. A thorough history was taken followed by clinical oral examination, and relevant radiological investigation was done. Literature research: In 2020, electronic literature searches were carried out in PubMed and complemented by a careful assessment of the reference lists of the identified relevant papers. Articles and reports fulfilled the inclusion criteria: indexed reviews, case series and case reports in English and restricted to human studies were considered.

RESULTS

The intraoral examination revealed multiple dental abscesses and general periodontal disease; the radiographic examination showed poorly defined lamina dura, large pulp chambers and periapical lesions. Based on the contents of the 43 articles identified in the search, the current knowledge of dental manifestations, treatment and management of HR was summarized.

CONCLUSIONS

As HR is a multisystem disease, multidisciplinary care is needed. By summarizing current evidences, we proposed an evidence-based dental management and provided recommendations on diagnosis and treatment of the disease. It is of profound clinical significance to acquire knowledge of the dental manifestations and provide optimal treatment options for patients.

Role of calcium and phosphorous concentration as an intrinsic factor in the development of skull fracture following road traffic accidents

INTRODUCTION

Traumatic brain injury (TBI) or head injury is one of the leading causes of morbidity and mortality globally. TBI includes a fractured skull as an indicator of insult which can affect the treatment outcome as well. The development of any fracture depends on a combination of factors defining the intrinsic properties of the bone and the extrinsic factors related to the impact. A decrease in bone mass secondary to deficiency of calcium (Ca) and phosphorus (P) can be a significant factor intrinsic to the skull bone, which can modulate the outcome of the impact by increasing the susceptibility of bones towards fractures. We undertook this research to find out whether or not the Ca and P concentration in skull bone has a role to play as an intrinsic factor, in the development of skull fracture following Road Traffic Accidents (RTAs).

METHODOLOGY

In this case-control study conducted for two years, we collected 94 bone samples, i.e. 47 each, from skull bones with head injuries following RTA, with (case) and without (control) fracture of the skull. The elemental analyses for the bony concentration of Ca and P in both the groups were then compared using energy dispersive X-ray (EDX). Unpaired t-test and Fisher's exact test was used for statistical analysis.

RESULTS

The elemental analysis of bones provided evidence that suggests that whilst; Ca is the only mineral that appears to have a significant correlation with the development of fracture skull, the overall Ca: P ratio of less than 1.99 increases the chances of skull fracture by 3.9 times.

CONCLUSIONS

Both individual bony Ca concentration and Ca: P ratio can be regarded as important intrinsic factors for the development of skull fracture.

Prosthetic rehabilitation of a patient with X-linked hypophosphatemia using dental implants: a case report and review of the literature

BACKGROUND

X-linked hypophosphatemia is associated with a range of dental problems, many of which may result in early loss of the dentition. Most patients, but especially young adults, are likely to desire fixed prosthodontic replacements, and dental implants may be the preferred solution in many cases. The use of dental implants to rehabilitate this patient group has not been widely studied with the literature limited to a small number of case reports with limited follow-up.

CASE PRESENTATION

This case report describes the dental journey of a young adult with X-linked hypophosphatemia, his eventual tooth loss and rehabilitation with multiple dental implants. Over 10 years' follow-up of three of the fixtures is presented.

CONCLUSIONS

This case report shows a common presentation and progression of a patient with X-linked hypophosphatemia and will hopefully provide further positive evidence for the clinician to rely on when considering dental implant based treatments for such patients.

Review of the dental implications of X-linked hypophosphataemic rickets (XLHR)

OBJECTIVES

The aim of this article was to review the dental implications of X-linked hypophosphataemic rickets (XLHR) and to provide suggestions regarding the dental treatment of these patients.

MATERIALS AND METHODS

The following search items "x-linked hypophosphataemia, hypophosphataemic rickets, vitamin D-resistant rickets" were used for literature search. Only full-text articles were analysed and summarized to get an overview of the different treatments and outcomes of hypophosphataemic patients.

RESULTS

Radiographically, very large pulp chambers with an abnormally high pulp volume/tooth volume ratio, suggesting taurodontism, are often evident. The affected teeth are characterised by a thin enamel layer and dentinal defects. The gender distribution of hypophosphataemic patients is almost equal, but postpubertary males seem to show a trend to develop more severe dental symptoms of the disease. Abscesses without any signs of dental caries or trauma are frequent findings. The most often affected teeth are incisors followed by molars and premolars.

CONCLUSIONS

Treatment options include frequent dental examination, application of topical fluoride varnish and sealing of pits and fissures to prevent microbial invasion that may result in pulpitis and further endodontic complications.

CLINICAL RELEVANCE

X-linked hypophosphataemic rickets is associated with marked structural alterations of dental hard tissues and the development of multiple abscesses and sinus tracts of dental origin. Therefore, profound knowledge of the various dental implications of XLHR is required to provide these patients with the best possible treatment options.

Dentin alteration of deciduous teeth in human hypophosphatemic rickets

Familial hypophosphatemic rickets is in most cases transmitted as an X-linked dominant trait and results from mutation of the PHEX gene, predominantly expressed in osteoblast and odontoblast. Patients have been reported to display important dentin defects, and therefore, we explored the dentin structure, composition, and distribution of extracellular matrix (ECM) molecules in hypophosphatemic human deciduous teeth. Compared to age-matched controls, the dentin from hypophosphatemic patients exhibited major differences: presence of large interglobular spaces resulting from the lack of fusion of calcospherites in the circumpulpal dentin; defective mineralization in the interglobular spaces contrasting with normal Ca-P levels in the calcospherites on X-ray microanalysis; abnormal presence of low-molecular weight protein complexes recognized on Western blots by antibodies against matrix extracellular phosphoglycoprotein (MEPE), dentin sialoprotein, osteopontin, and reduced osteocalcin (OC) level; and accumulation in the interglobular spaces of immunolabeling with antibodies against DSP, dentin matrix protein, bone sialoprotein, MEPE and OC, while chondroitin/dermatan sulfate glycosaminoglycans were exclusively located inside calcospherites. Alterations of the post-translational processing or partial degradation of some ECM appear as key factors in the formation of the defective hypophosphatemic dentin.

Pathohistology of undecalcified primary teeth in vitamin D-resistant rickets: review and report of two cases

The basic dental defects in vitamin D-resistant rickets seem to be manifested in dentin. Enamel is usually reported to be normal. This histologic examination showed the penetration of microorganisms through the calcified structures of the enamel layer without visible caries. The microorganisms passed through the dentinoenamel junction and invaded dentin, which was characterized by calcospherites and large amounts of interglobular dentin. Furthermore, microorganisms could be detected in dentinal tubules, which were exposed to the oral cavity when enamel was removed. However, large areas of tertiary dentin extended between such tubules and the pulp. These light microscopic results suggest that clinical manifestations, such as, pulp recrosis and periapical lesions (without carious defects) may be caused by the penetration of microorganisms through microclefts of the enamel layer as well as pathologically altered enamel microstructures of affected teeth.

Energy-dispersive X-ray microanalysis of the bone mineral content in human trabecular bone: a comparison with ICPES and neutron activation analysis

To evaluate the accuracy of bone mineral composition determination by electron microprobe analysis (EDX) the measurements have been compared to instrumental neutron activation analysis (INAA) and chemical analysis (ICPES). Bone specimens from five femoral heads were used. The trabecular content of calcium (Ca) and phosphorus (P) was analyzed by the three different methods. The EDX method allows for a microstructural analysis of intact, methylmetacrylate-embedded, undecalcified bone and the measuring points can thus be distinctly identified centrally in each trabecula. The analysis yielded 25.8 +/- 0.7 wt % Ca and 10.5 +/- 0.1 wt % P, compared with 22.2 +/- 0.5 and 23.0 +/- 1.0 wt % Ca, and 9.83 +/- 0.21 and 10.02 +/- 0.44 wt % P for INAA and ICPES, respectively. The EDX analysis was calibrated by consecutive measurements of a hard, pressed tablet of hydroxyapatit of known content. The mean Ca content deviated with -0.38 wt % from the given content and P with -0.89 wt %. We could not verify any particular interference from the embedding procedure, however, it is possible that the relatively lower P content still may reflect this. The magnesium (Mg) concentration was 0.31 +/- 0.02 wt % by EDX and 0.26 +/- 0.02 wt % by INAA. The EDX analytical method provides a useful tool for simultaneous elemental quantification in bone. It has the advantage of permitting the use of regular bone biopsy material and thus allowing for a unique microstructural evaluation of the degree of mineralization.(ABSTRACT TRUNCATED AT 250 WORDS)