Conventional complete overdenture will be made to ectodermal dysplasia patients, a week after delivery and after 3 months Patient satisfaction, retention and periodontal condition will be assessed. the denture will be taken from the patient for 2 weeks.Acrylic telescopes will be replaced with soft liner and again Patient satisfaction, retention and periodontal condition will be assessed a week after delivery and 3 months later.

Upper and Lower Primary impressions will be carried out by using irreversible hydrocolloid (Alginate, Tropicalgin, Normal setting, Zhermack, Italy) according to manufacturer's instructions using stainless steel stock trays.

Secondary upper impression is done with an acrylic special tray. Border molding is done with putty consistency rubber base impression material, Final impression with medium consistency rubber-base impression material (Silicone impression material, Elite P&P, Regular Body-Normal set, Zhermack, Italy) Maxilla-mandibular relationship will be recorded using check bite technique. Setting of artificial teeth will be performed and trial dentures will be tried in inside patients' mouth.

The finished and polished dentures will be delivered immediately after the necessary occlusal adjustments and instructions regarding hygiene and maintenance.

The patient will use the upper overdenture for 3 months. The overdenture is taken from the patient for two weeks, after which the maxillary overdenture will be adjusted by relieving acrylic opposite to the abutment about 2 mm using a metal stone. The relieved areas will be painted with an adhesive and the rest of the fitting surface of the denture will be painted with a separating medium.

The soft liner (Silicone based soft liner, mollosil, chairside soft relining-long term, DETAX, Germany) will then be applied in the relieved areas to act as a secondary coping The base and catalyst will be mixed according to the manufacturer's instructions on a glass slab. The mix will be placed on the relieved area, seated in the patient's mouth, the patient is asked to bite in centric relation and the excess liner is removed with a lancet.

Inclusion Criteria:

1. Partially edentulous ectodermal dysplasia patients with few remaining teeth.
2. Cooperative patients with no history of psychological diseases.
3. Length of maxillary remaining teeth should not be less than 4mm.

Exclusion Criteria:

- 1- Patients with tempo-mandibular joint disorders or systemic or neuromuscular disorder that might affect chewing efficiency of masticatory muscles.

2- Patients allergic to acrylic resin.