International Journal of Prosthodontics & Restorative Dentistry
Volume 11 | Issue 4 | Year 2021

Implant-supported Collapsible Overdenture for Scleroderma Patients

Sheen S Mehta1, Dushyant Soni2, Swathi K Sharma3, Tondon D Athokpam4

1-4Department of Prosthodontics, Vyas Dental College & Hospital, Jodhpur, Rajasthan, India

Corresponding Author: Sheen Singh Mehta, Department of Prosthodontics, Vyas Dental College & Hospital, Jodhpur, Rajasthan, India, Phone: +91 7378583596, e-mail:


Tightening of the skin around the oral aperture causes the mouth opening to become limited in scleroderma patients. The limited oral opening can make prosthetic treatment challenging. A lady patient, 28 years of age, reported with a complaint of pain in relation to upper teeth and difficulty in chewing food. She gave a history of being diagnosed with scleroderma 3 years back and desired a suitable prosthesis for restoring her function and esthetics. This clinical paper presents the prosthodontic management of a highly resorbed edentulous mandible of a patient with restricted mouth opening by an implant-supported collapsible overdenture.

How to cite this article: Mehta SS, Soni D, Sharma SK, et al. Implant-supported Collapsible Overdenture for Scleroderma Patients. Int J Prosthodont Restor Dent 2021;11(4):202-205.

Source of support: Nil

Conflict of interest: None

Keywords: Complete denture, Dental implants, Denture base, Esthetics, Impression techniques, Mandibular overdenture


Scleroderma is an autoimmune multisystem rheumatic condition involving the connective tissues and blood vessels leading to fibrosis.1,2 This is clinically characterized by tightening of skin and mucosa. Scleroderma leads to both vascular injury and overproduction of normal collagen.3 Excess collagen so produced leads to the first symptom of scleroderma, deformity of the fingers and toes, called sclerodactyly, caused by reduced blood circulation, called Reynaud’s phenomenon. At the onset, edema of the face, and extremities ensues followed by loss of elasticity. Oral manifestations include trigeminal neuropathy, xerostomia due to fibrosis of salivary glands, thickened periodontal ligament due to vascular changes.4 Difficulty to rehabilitate arises by narrowing of the oral aperture and rigidity of the tongue. In some scleroderma patients, there is mandible bone resorption in nontooth bearing areas. The inferior border, posterior border of the ramus, the angle, the coronoid, and condylar process. This is related to associated muscle atrophy, the pressure of the tightening skin overlying the bone, and vascular changes.5 Sectional dentures have been recommended for such patients. A maxillary complete denture consisting of two pieces joined by a stainless steel rod fitted behind the central incisors was described by McCord.6 A sectional impression procedure for the edentulous patients described by Luebke, used two plastic sectional impression trays assembled with lego building blocks and autopolymerizing resin trays.7

This clinical report describes the fabrication of an implant-supported foldable overdenture with O- ring attachment for a scleroderma patient with microstomia and atrophic mandible.

Case Description

A 28-year-old lady patient reported to the Department of Prosthodontics, Vyas Dental College & Hospital, Jodhpur, with a complaint of pain in relation to upper teeth and difficulty in chewing food. She gave a history of being diagnosed with scleroderma 3 years back. She had been prescribed tab methotrexate 15 mg, and tab hydroxychloroquine 200 mg since then. On clinical examination the patient had shown deformities of the fingers and toes (Figs 1A and B). There was restricted mouth opening around 25 mm due to fibrosis and stiffness of the peri-oral skin (Fig. 1C). She had multiple carious lesions in relation to the upper teeth and a completely edentulous atrophic mandible. The oral mucosa was very thin and the bone in the mandibular anterior region was irregular and knife-edged. She was advised an OPG for evaluation.

Figs 1A to C: (A and B) Full-thickness flap was raised; (C) Restricted mouth opening

The patient was referred for endodontic consultation of the multiple caried teeth in the upper arch and simultaneously was given various fixed and removable treatment options for the edentulous mandible, like all on four or two implants supported overdenture. A conventional complete denture however was ruled out. She was informed of the limitations due to her restricted mouth opening and the need to modify her prosthesis design to a collapsible or foldable one. Patient agreed to an overdenture as this needed minimal surgical intervention and suited her economically. Signed informed consent was obtained from the patient.

On the day of surgery, local anesthesia was infiltrated (xylocaine, 2% lignocaine hydrochloride with adrenaline) in the anterior mandibular region and a full-thickness flap was raised (Fig. 2A). The irregular knife-edged bone was leveled out with a handpiece and two implants (ADIN TOUAREG 3.5X13) were placed anterior to the mental foramen in A and E positions (Fig. 2B). Ideally, implants are best inserted in the B and D positions8 as they limit the forward rocking and place least leverage forces, however considering patients bone condition and her reluctance to get a bone graft, implants were planned in A and E positions. The flap was reapproximated and sutures were placed. Postoperative instructions and medications including antibiotic therapy (amoxicillin clavulate potassium 625 mg, tab metronidazole 400 mg, tab aceclofenac were prescribed. The patient was recalled after 10 days and the sutures were removed. Cover screws were removed and healing abutments were placed.

Figs 2A and B: (A) Resorbed mandibular ridge; (B) A and E position for implant placement

The prosthetic phase commenced after 2 months when the patient was recalled and the placed implants were evaluated radiographically, marginal bone loss was acceptable and no peri-implant radiolucency was observed. They showed sufficient primary stability as seen with tactile perception and application of 30Ncm reverse torque. Small 1 mm ball attachments were selected for the patient due to their low profile. Primary impressions were made using putty silicone impression material (Acquasil) with the help of finger support without using any trays. The primary cast was obtained by pouring the impressions (cerestone). A custom tray using autopolymerizing resin (DPI cold cure) was prepared on the mandibular cast. Four metal die pins each of diameter 2.5 mm were attached, the central two in the region between the edentulous sites of lateral and central incisors, being 15 mm and two pins in the molar areas bilaterally being 25 mm each. The short pins were placed over the residual ridges and the long pins close to midline. The acrylic tray was lubricated with petroleum jelly, and an acrylic resin block is prepared. This resin index slid tightly on the pins (Fig. 3A).

Figs 3A to D: (A) Pins used as locking device and acrylic block to stabilize the two halves; (B) Border molding done in sections; (C) Assembled trays after reapproximation of fracture line; (D) Master cast

Mandibular special tray is than cut into two halves. The sectioned trays were then joined by acrylic resin block, which slid into the parallel pins. The restricted oral opening did not allow the placement of the special tray along its normal circumference hence acrylic resin index was slid vertically upwards on the long pins, tray was than inserted into the patient’s mouth in one piece because the tray could be folded in horizontal plane. It was seated in correct position using the acrylic block. Border moulding was done first for the right and later for left halves of the sectional trays (Fig. 3B). On each halves of the tray, final impressions were made by using zinc oxide eugenol impression paste (DPI impression paste). The two halves were stabilized intraorally using the acrylic resin index. After the impression paste was set the block was carefully detached in the mouth. Both the sections of the impression trays removed individually by fracturing the impression material. Fracture line of the two halves were evaluated and checked if it joined smoothly, Acrylic index was than slid again to join the two halves outside the mouth (Fig. 3C), dental stone (Neelkanth, stone plaster) was poured to fabricate the master cast (Fig. 3D).

The mandibular denture base was prepared in two pieces right and left. These pieces were joined by overlapping over each other around 2 mm in the midline. Space was made to fit a small stainless steel hinge with autopolymerizing resin in the centre lingually (Fig. 4A and B). Occlusal rims were made and jaw realtions were done for the mandible.A bite was obtained of the upper teeth into the wax. Mounting and teeth arrangement were done. The try-in sectional denture was evaluated and heat cure acrylization was carried out. To prevent the flow of resin into the connecting area of the denture, putty was placed into the gap in the hinge design. Finishing and polishing of the denture was done.

Figs 4A and B: Hinge device fitted into the denture base

Ball attachments were attached to the implants after removing the healing caps (Fig. 5A). The denture was placed in the mouth to evaluate the location of the attachments, space was created using a trimmer, marked by the disclosing paste. After adequate placement on the attachments was confirmed, (Figs 5B and C) extra acrylic was removed and the denture was polished (Fig. 6A). The denture insertion was done and occlusion was checked (Figs 6B and C). Home care instructions were given. Information about maintenance of the implants and O ring as well as the hinge device by following strict cleaning routine of the denture with a soft-bristled brush, periodic recalls evaluating the fit and wear of O rings and the hinge device was given. The patient was advised not to use alcohol-based cleaning solutions as they may dry and hasten the wear of O rings9,10 and dip the dentures in plain cold water while not in use.

Figs 5A to C: (A) O ring and housing attached to the implants; (B and C) Transferred to the denture

Figs 6A to C : (A) Final denture; (B and C) Left and right lateral view


Limited oral opening in a scleroderma patient can pose a major dental problem and general difficulties of reduced access become even more apparent when giving prosthesis. A variety of pins, bolts, and lego pieces have been used for the locking mechanism of sectional impression trays fabricated for such patients.11 Others have advocate the use of hinges for making collapsible dentures.12 In this patient parallel pins and slidable acrylic index served as the locking mechanism. The use of different size pins made it possible for the mandibular tray to be folded. A simple hinge was used in the lingual aspect of the denture to make it collapsible. The most important requirement when sectional trays are used is the mechanism to accurately adapt and stabilize the two segments of the tray to each other both intraorally and extraorally. Locks need to be placed both anteriorly and posteriorly. Also, the technique should be noncomplicated and allow easy manipulation. The technique in this report fulfills all the criteria.13,14 The major advantages of this technique are simplified tray design, ease in fabrication, nonusage of convoluted machineries, or joining devices. The stainless steel hinges are easily available and are easy to maintain. Even this technique has its own limitations such as increased time, materials, and patient appointments and need for periodic recalls to assess the abutment screw loosening and wearing off of the O rings. However, the long-term success was obtained by periodic review, maintenance, and patient acceptance.

By making modifications in techniques right from the stage of impression making to acrylization, prosthodontic restoration of patients with the limited oral opening is possible. Implant-supported overdentures can be placed in the resorbed ridges and flexible or foldable dentures may be delivered to provide ease of fit and convenience of use.


All authors have contributed equally to the work.


Sheen S Mehta


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