By Birgitta Bergendal, D.D.S., Ph.D. and Ia Nielsen
Very young individuals with hypohidrotic ectodermal dysplasia (HED) and mandibular anodontia (total absence of primary as well as permanent teeth) have undergone dental implant treatment since the mid-1980s. Consensus conferences in Jönköping, Sweden in 1996 and 1998 advised the lowest age for treatment with dental implants in this group of patients to be around six years.
The age of six has been recommended because the median suture, where transversal growth occurs, is normally closed at this time. This recommendation is based on analysis of growth of the mandible in children without ectodermal dysplasia. A first treatment using a removable overdenture attached to one implant in the canine region on each side of the mandible can then be performed.
In the literature, there are several case reports describing successful outcomes of this kind of treatment in children. The first one reported on a Swedish boy with x-linked HED (1). A larger prospective study from the United States reported on implant treatment in 51 patients with ectodermal dysplasia, both children and adults. (2) The results were presented as favorable, but on closer view, the failure rates were higher than in individuals without ectodermal dysplasia.
In a questionnaire study of 109 American individuals with ectodermal dysplasia, higher rates of complications and loss of implants were reported than in studies on individuals without ectodermal dysplasia. (3) Half of the patients reported complications and 24% reported some kind of failure.
A Swedish study reported on treatment in five children with HED who were treated with implants in the anodontic mandible from five to 12 years of age. (4) All but one boy lost one or more implants shortly after the operation. The four who lost implants were re-operated, most of them with a successful outcome. The losses of implants were attributed to the small size of the jaws and the hard bone, which made the operation technically complicated.
Later, French researchers have shown that the molecular signalling pathway in HED (EDA-EDAR-EDARADD) leads to a transcription factor, NFκB, which affects bone and gives it a different structure and increased hardness. (5) This finding was confirmed in an Australian study where 3D-images from bone samples from young individuals with ectodermal dysplasia were compared to samples from older edentulous individuals without ectodermal dysplasia. (6) Also, individuals with incontinentia pigmenti and mutations in the NEMO-gene probably have harder than normal bone.
With this background, we now advise implant operations to be postponed to around eight years of age in children missing all teeth in the lower jaw.
The surgeon performing the operation should be prepared for the bone to be very hard. After growth is finished, from around 18 years of age, additional implants can be installed and a fixed dental prosthesis can be made. The treatment should then be followed by regular dental check-ups.
A case-report published in 2015 provided 30 years of detailed follow-up on the successful treatment of a Swedish boy, who received his first implants at six years of age. (7)
Patients with HED who have some primary and/or permanent teeth can, if needed, be treated with different forms of tooth-supported removable or fixed appliances during childhood and adolescence. Treatment of these patients with dental implants can be performed after growth is almost completed in the late teens.
Editor’s Note: If you or your child are affected by HED and considering dental implant treatment, Dr. Berendal suggests that you print this information about the hard bone and share with your dental care team:
Clinical Advice for Dental Implant Operations in Children and Adults with Hypohidrotic Ectodermal Dysplasia
Individuals with ectodermal dysplasia often have very hard bone with compromised blood flow.
Be well-prepared and take the following precautions:
- careful choice of burs, pre-tapping if necessary
- drill slowly with generous irrigation
- avoid bone substitutes if possible
- consider postoperative antibiotics
The operation should be performed by a skilled surgeon at a specialist clinic.
1. Bergendal T, Eckerdal O, Hallonsten AL, Koch G, Kurol J, Kvint S. Osseointegrated implants in the oral habilitation of a boy with ectodermal dysplasia: a case report. Int Dent J 1991;41:149-156.
2. Guckes AD, Scurria MS, King TS, McCarthy GR, Brahim JS. Prospective clinical trial of dental mplants in persons with ectodermal dysplasia. J Prosthet Dent 2002;88:21-25.
3. Stanford CM, Guckes A, Fete M, Srun S, Richter MK. Perceptions of outcomes of implant therapy in patients with ectodermal dysplasia syndromes. Int J Prosthodont 2008;21:195-200.
4. Bergendal B, Ekman A, Nilsson P. Implant failure in young children with ectodermal dysplasia: A retrospective evaluation of use and outcome of dental implant treatment in children in Sweden. Int J Oral Maxillofac Implants 2008;23:520-524.
5. Lesot H, Clauss F, Manière MC, Schmittbuhl M. Consequences of X-linked hypohidrotic ectodermal dysplasia for the human jaw bone. Front Oral Biol 2009;13:93-99.
6. Silthampitag P, Klineberg I, Jones AS, Austin B, Zee KY, Wallace C, Scholz S, Naim A, Zoud K. Ultramicroscopy of bone at oral implant sites: a comparison of ED and control patients. Part 1- defining the protocol. Int J Prosthodont 2011;24:147-154.
7. Bergendal B, Bjerklin K, Bergendal T, Koch G. Dental Implant Therapy for a Child with X-linked Hypohidrotic Ectodermal Dysplasia – Three Decades of Managed Care. Int J Prosthodont 2015;28:348-356.