2022 Volume 10 Issue 2
Creative Commons License


Akshyaa Balaji1, Jeyaraj Brintha Jei1*, Krishnan Murugesan1, Balasubramanium Muthukumar1

1Department of Prosthodontics, SRM Dental College, Ramapuram, Chennai, Tamilnadu, India. [email protected]


Kennedy’s class I and class II situations are at times very challenging to rehabilitate especially when opposing a complete denture. The tooth and tissue are supported and hence the retention of the prosthesis may sometimes be compromised due to the nature of the residual tissues. Ideally implant supported prosthesis are considered to be the most favorable treatment option for these patients but their systemic health status may not be suitable for the same. A conventional cast partial denture with clasps can be given, but they are unaesthetic and hence not accepted by patients. An alternative to this is the extra-coronal attachment retained prosthesis. They are combined fixed and removable prosthesis that are an easier alternative as compared to implant supported prosthesis and more aesthetic compared to clasp retained cast partial dentures. This current case report involves rehabilitation of Kennedy’s class I situation opposing a complete denture using extra coronal attachments.

Key words: Distal extension, Semi-precision, Attachments, Cast partial dentures, Precision.




Rehabilitation of distal extension conditions is sometimes very difficult because these are supported by tooth and tissue and require sound abutment teeth. This becomes more critical when a completely edentulous arch opposes it. Usually, a fixed prosthesis cannot be given for a distal extension condition due to long cantilever length, which may be deleterious [1]. An implant-supported prosthesis may exploit the patient financially. Nevertheless, a conventional clasp retained cast partial denture compromises the aesthetics due to exposure of the metallic components. This can be overcome by using extra-coronal attachments (precision or semi-precision) [2, 3].

Semi-precision attachments are those in which the wax pattern for the attachment is made manually in the wax pattern and cast conventionally. In contrast, precision attachments are prefabricated alloys that can be incorporated directly into the restoration. It is due to this reason that the retention with precision attachments is superior to those of semi-precision attachments. The extra-coronal attachments retained cast partial dentures to enhance both esthetics and are better in function. The survival rates of such prostheses are also satisfactory, 83.35% for five years and up to 50% for 20 years [4, 5].

This case report describes the management of Kennedy’s class I modification in one situation in maxillary arch using semi-precision attachments retained cast partial denture opposing a completely edentulous mandibular arch.

Case report

A 68 years old male patient reported to the Department of Prosthodontics with the chief complaint of difficulty in chewing food since the last one month when he got multiple extractions of his natural teeth as they were mobile. On clinical examination, 13 to 23 were the only natural teeth remaining. Grade III mobility was seen with 12 and 11 and hence were indicated for extraction. OPG revealed a generalized bone loss in the maxilla and mandible. Following extraction, the maxillary arch was Kennedy’s class I modification, and the mandibular was completely edentulous (Figure 1). After the required periodontal treatment and primary analysis of the diagnostic casts, treatment was planned, which consisted of a tooth-supported fixed prosthesis from upper right canine to left canine and semi-precision attachments distal to the abutments with a cast partial removal denture in the maxillary arch and a conventional complete denture in the mandibular arch. The implant-supported prosthesis could not be planned due to his systemic condition- uncontrolled diabetes and undergoing antiplatelet therapy. The most non-traumatic treatment was chosen for the patient taking into account his systemic condition.

Figure 1. Preoperative view

Denture bases with self-cure acrylic resin (DPI dental products, Mumbai, India) were made on the diagnostic casts, followed by occlusal rims using modeling wax (Hindustan Dental Products, Hyderabad, India). The patient’s vertical dimension and a tentative centric relation were recorded and articulated using these. Tooth preparation was done atraumatic with supragingival margins irt 13,21,22, and 23. Following this, impressions were made using monophase impression material (Dentsply Aquasil Monophase, Dentsply Sirona, India) for the maxillary arch (Figure 2). Border molding and wash impressions were done using low fusing impression compound (DPI Pinnacle Tracing Sticks, DPI Dental Products, Mumbai, India) and zinc oxide eugenol impression paste (DPI Impression paste, DPI Dental Products, Mumbai, India) for the mandibular arch. On the master cast, wax patterns for metal copings were made, and distal to the abutments, prefabricated castable OT cap Rhein 83 Inc, USA attachments were added (Figure 3). These are extra-coronal attachments with elastic retention. These also act as a stress breakers and absorb the excess stresses. The male portion is attached to the wax pattern of the FPD, and the female portion is present on the cast partial denture.