Two-Implant-Retained Overdentures using Locator Attachments in Completely Edentulous Patients with Severely Resorted Mandible: A Report of Two Cases

Special Article - Dental Implants

J Dent App. 2016; 3(2): 315-318.

Two-Implant-Retained Overdentures using Locator Attachments in Completely Edentulous Patients with Severely Resorted Mandible: A Report of Two Cases

Kaneko T*, Nakamura S, Hino S, Horie N and Shimoyama T

Department of Oral and Maxillofacial Surgery, Saitama Medical Center, Saitama Medical University, Japan

*Corresponding author: Kaneko T, Department of Oral and Maxillofacial Surgery, Saitama Medical Center, Saitama Medical University, 1981 Kamoda, Kawagoe, Saitama 350-8550, Japan

Received: August 29, 2016; Accepted: September 20, 2016; Published: September 22, 2016


Implant-retained overdentures (IODs) offer advantages in terms of lessinvasive surgery, ease of cleaning, and cost-effectiveness. Use of an IOD supported by two implants (two-IOD) has been advocated as the minimal standard of care for the treatment of an edentulous mandible. We describe two cases in which a two-IOD was applied using Locator attachments for completely edentulous patients with severely resorbed mandibles. Case 1 showed a severely atrophic mandible requiring major bone augmentation for the fixed implant prostheses. Case 2 had a severely atrophic mandible and complex medical history. Both cases were treated with a two-IOD using Locator attachments for reasons of treatment cost, minimizing surgical damage, and systemic condition of the patient. Outcomes of prostheses were evaluated using chair side scoring to measure masticatory function.

Keywords: Two-implant-retained overdenture; Locator attachment; Dental implants; Severely atrophic mandible


CAD/CAM: Computer Aided Design/Computer Aided Manufacturing; CT: Computed Tomography; IOD: Implant- Retained Overdenture


A completely edentulous jaw might result in systemic problems such as dyspepsia and poor nutritional status, as well as incomplete mastication and dysphagia in the oropharyngeal region. Under conditions of oral dysfunction due to an edentulous jaw, dental implants can restore both esthetic and functional deficits and have demonstrated significant improvements in quality of life for edentulous patients [1]. For treatment variation of implants, both fixed and removable prostheses can be successfully applied to edentulous jaws. Implant-retained overdenture (IOD) is favorable in terms of reducing the invasiveness of surgery [2], decreasing the costs [3], and facilitating hygiene rehabilitation [4]. Although these prostheses can be anchored to the implants with splinted attachments such as a bar or unsplinted attachments such as ball anchors, Locators, double crowns, and magnets [5], bar attachment needs more space within the denture than unsplinted attachments, and is often difficult to accommodate with anchorage attachments. In addition, fabrication and results of prostheses are sensitive to the skill of the dental technician [6]. In contrast, an IOD using unsplinted attachment is more suitable for a large number of patients because of the smaller space requirements within prostheses and the simple fabrication process [6-8]. In the McGill Consensus Statement on overdentures, the two-IOD has been advocated as the minimal standard of care in the treatment of an edentulous mandible [2].

This article describes two cases of two-IOD using Locator attachments in completely edentulous patients with severely resorbed mandible and systemic disease.

Case Presentation

Case 1

The patient was a 71-year-old man who was referred to our department for dental implant therapy due toa chief complaint of masticatory disturbance caused by unstable complete lower dentures. He had past histories of well-controlled diabetes mellitus and hypertension. Oral examinations revealed that both the maxilla and mandible were edentulous, and the alveolar ridges in the region of the mandibular molars were flattened (Figure 1). Orthopantomography showed severe resorption of mandibular bone, and the alveolar crest was extremely close to the mandibular canal (Figure 2). The patient was informed of the details of the treatment options, including implantfixed prostheses associated with bone augmentation and IOD. Because of the surgical damage and time required for bone augmentation and treatment cost, two-IOD was selected for treatment, and Locator attachments (Kerator Overdenture attachment system; KJ Meditech, Gwang-iu, Korea) were adopted as the retention device to improve denture stability. Prior to implant surgery, conventional upper and lower full dentures were newly fabricated. A radiographic template was then prepared from the duplicate dentures and data from computed tomography (CT) were utilized in image analysis software (S implant Pro TM; Materialise Dental NV, Leuven, Belgium) to gather diagnostic information for proper implant placement. CT showed that alveolar crest height was severely reduced in the molar regions, especially in the left molar region (Figure 3A and 3B). Bilateral mental for amina were observed in the alveolar crest sites. However, sufficient bone had been maintained in the canine-lateral incisor area to make implant insertion possible (Figure 4), and two implants (Osseo speed TX; Dentsply IH AB, Mölndal, Sweden) were placed with sufficient initial stability (Figure 5). Abutment connection was performed 2months after implant insertion (Figure 6), and a nylon male cap was incorporated into the denture base. After setting the two-IOD, denture stability was markedly enhanced, and occlusal force and masticatory function were significantly improved (Figure 7). As of more than 3years since setting the two-IOD, no problems have been observed.