XLH  is  the  most  common  form  of  inherited  rickets.  

Genetic  Defect:    loss-­‐of-­‐function  mutations  in  PHEX,  leading  to  elevated  circulating  levels  of  Fgf23,  resulting  in  impaired  renal  conservation  of  phosphate    

Systemic  Effects:    rickets,  osteomalacia,  growth  retardation,  and  dental  effects    

Oral  Manifestations:  “Spontaneous”  abscesses,  possible  delay  of  eruption,  delay/lack  of  apical  closure,  increased  frequency  of  malocclusion,  periodontal  disease  

     

Requests  for  additional  information  or  specific  questions  may  be  directed  to*:    Leslie  Blackburn,  DDS,  MA  leslie.blackburn@yale.edu  leslieblackburn0204@gmail.com                  *Please  include  XLH  in  the  email  subject  line.  

1  Long  Wharf  Drive,  Suite  403    New  Haven,  CT,  06510  

http://www.ynhh.org/medical-­‐services/dental_pediatricaspx  

Yale-­‐New  Haven  Pediatric  Dental  Center  

XLH:  A  Review  

X-­‐Linked  Hypophosphatemia  

 Information  for    

Dental  Practitioners  Questions?  

 

 

 

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*Note:  Most  of  the  XLH  literature  is  in  the  form  of  case  studies  and  also  the  findings  are  extremely  varied;  thus  the  abnormalities  noted  below  may  be  present  in  any  combination  (or  not  at  all)  in  any  one  individual.  

Structural  Defects:    Enamel:    Possible  hypoplasia  or  hypocalcification;  some  suggestion  that  patients  may  have  thin  or  more  easily  abraded  enamel  and  microcracks.  

Dentin:    1-­‐Mantle  dentin  and  most  circumpulpal  dentin  is  normal,  dentin  intermediate  to  those  areas  displays  large  interglobular  areas  with  unmerged  calcospherites.    2-­‐Dentinal  (tubular)  clefts  in  the  area  of  the  pulp  horns.  3-­‐Decreased  ability  to  form  tertiary  dentin.  

Pulp:    Large  pulp  chambers  with  high  pulp  horns  (sometimes  extending  to  the  DEJ).  

Cementum:    May  be  thin.  

Alveolar  bone:  Possible  absence  of  lamina  dura.  

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Oral  Sequelae  Observed  in  XLH:    

“Spontaneous”  Abscesses    periapical  abscesses  seen  without  evidence  of  caries  or  trauma;  reported  in  both  primary  and  permanent  dentitions  *This  is  the  most  prevalent  oral  manifestation  of  XLH.    Increased  Risk  of  Iatrogenic  Damage  because  the  pulp  horns  are  so  high,  it  is  easy  to  have  an  iatrogenic  pulp  exposure  during  routine  restorative  care    Periodontal  Disease    possible  increase  in  risk  of  periodontal  disease,  and  also  increase  in  severity  of  periodontal  disease    Increased  Sensitivity  During    Periodontal  Treatment    if  present,  may  be  due  to  increased  severity  of  disease  and  possible  thinning  of  cementum  

Structural  Defects  in  XLH  Teeth  and  their  sequelae  

 

Treatment  in  XLH  Patients  

Preventive  Routine  exams  to  monitor  for  spontaneous  abscesses  are  critical.  

Dietary  guidance  and  oral  hygiene  instruction  should  be  emphasized.  

Sealants  may  be  efficacious  to  prevent  access  through  cracked,  abraded,  or  compromised  enamel  and  dentin.  

Nightguards  may  be  considered  to  protect  easily  abraded  enamel.  

 

Interceptive  Restorative  treatment  should  be  undertaken  with  care  to  avoid  iatrogenic  pulp  exposure  due  to  large  pulp  chambers  and  high  pulp  horns.  

As  XLH  patients  who  experience  spontaneous  abscesses  often  have  many  such  abscesses  over  the  course  of  a  lifetime,  root  canal  therapy  and  other  such  measures  to  save  affected  teeth  are  preferable  to  extraction.