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Table of Contents
Year : 2022  |  Volume : 12  |  Issue : 2  |  Page : 115-119

Two implant-retained mandibular overdenture using locator attachment – A clinical report

1 Department of Prosthodontics, Burdwan Dental College and Hospital, Purba Bardhaman, West Bengal, India
2 Department of Dentistry, Malda Medical College and Hospital, Malda, West Bengal, India

Date of Submission11-Dec-2021
Date of Acceptance08-May-2022
Date of Web Publication10-Jan-2023

Correspondence Address:
Dr. Saurav Banerjee
Burdwan Dental College and Hospital, Purba Bardhaman, West Bengal
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jdi.jdi_33_21

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Success rates for osseointegrated dental implants in the anterior mandible are very high. Due to these success rates, as well as lower costs, it is common to treat edentulous patients with just two implants, which will act as anchors for retention of the overdenture. The implant-retained overdenture is an alternative treatment option in edentulous patient's rehabilitation, providing significant retention, stability, function, and esthetics. This clinical report highlights the prosthetic rehabilitation of a partially edentulous mandibular arch with implant-supported overdenture using locator attachment.

Keywords: Edentulism, implant, overdenture

How to cite this article:
Banerjee S, Mandal R. Two implant-retained mandibular overdenture using locator attachment – A clinical report. J Dent Implant 2022;12:115-9

How to cite this URL:
Banerjee S, Mandal R. Two implant-retained mandibular overdenture using locator attachment – A clinical report. J Dent Implant [serial online] 2022 [cited 2023 May 31];12:115-9. Available from:

   Introduction Top

Alveolar bone resorption is a progressive and irreversible phenomenon leading to edentulism, a poor health outcome and may compromise quality of life.[1] The amount and rate of alveolar bone resorption depend on several factors such as age, sex, facial anatomy, metabolism, oral hygiene, parafunctions, general health, nutritional status, systematic diseases, osteoporosis, drug administration and time of edentulism.[2],[3] Patients wearing conventional complete dentures will present with smaller edentulous ridges than edentulous patients with never receiving prosthesis.[4] The implant-retained prosthesis is an alternative treatment option in edentulous patient's rehabilitation, providing significant retention, stability, function and esthetics, and quality of life, especially in the mandible. Masticatory function significantly improves with implant-supported mandibular overdentures.[5] The use of implants for edentulous patients will actually preserve existing bone compared to conventional dentures.[6]

A study revealed that two-implant- and four-implant-supported overdentures exhibited the same degree of reduction in peri-implant fractal dimension over time, suggesting similar risk of failure because fractal dimensions is related to implant stability so two implant overdenture may be preferred since it requires less surgery and is less costly.[7] Removable overdentures are preferred over fixed-implant full-arch dentures in the edentulous mandible since they are more easy to clean and can be cleaned outside the patient's mouth, whereas the later requires much more time-consuming hygiene maintenance.[8]

Attachment systems available for implant-retained overdenture are ball attachment (O-Ring system, Locator Attachment, etc.,) or Bar and Clip Attachment (CM Bar and Rider/Ackermann Clips, Dolder Bar System, Häder Bar System/EDS System). When the inter-arch distance is inadequate for placing ball attachments, several problems may occur, such as over-contoured prosthesis, excessive occlusal vertical dimension, fractured teeth adjacent to the attachments, separation of attachments from the denture, fracture of the prosthesis, and overall patient dissatisfaction. Locator attachments can be a suitable alternative because of their lowest profile, self-aligning design, and angle correction up to 40°. This clinical report highlights the prosthetic rehabilitation of a partially edentulous mandibular arch with implant-supported overdenture using locator attachment.

   Case Report Top

A 60-year-old female patient reported with the complaint of missing teeth causing inability to masticate food and having difficulty in speech. She wanted the replacement of missing teeth so that the function and esthetics can be restored. Previous denture history revealed that it was a cause of constant soreness and irritation on the mandibular ridge. On examination, completely edentulous maxillary and mandibular arches, with knife-edge ridge in the mandibular arch was noted. Tooth number #34 and #35 were retained to minimize alveolar bone loss, short coping was made over the tooth. After clinical and radiographic evaluation, it was decided to rehabilitate the patient with a conventional denture for the maxillary arch and an implant-supported overdenture in the mandibular arch [Figure 1].
Figure 1: Preoperative intraoral view

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Diagnostic phase

Diagnostic casts were prepared from irreversible hydrocolloid impressions (Tropicalgin, Zhermack, Italy) and mounted on an articulator to analyze the inter-arch factors. The restorative space measured was about 15–18 mm. The patient's previous denture was duplicated in clear autopolymerising acrylic resin and was used as a radiographic and surgical template. Dimensions of the alveolar bone were measured through cone-bean computed tomography, and proper size implant was selected.

Surgical phase

Following prophylactic course of antibiotics, the patient was administered 2% of xylocaine with 1:200,000 epinephrine inferior alveolar, lingual and buccal nerve blocks at the proposed implant site area. A crestal incision was made with no: 15 B P blade and handle, and a full-thickness flap was raised to access the alveolar bone. The exact position of the implant was marked using the surgical template. The pilot drill was used to mark the proposed implant site and penetrate the cortical plate into the cancellous bone through the initial access. The subsequent drills were used as per the manufacturer's specifications to the required diameter and length. After the osteotomy done in mandibular right and left canine region, an endosseous root-form two-piece implant (EZ Hitech Implants (Israel) of diameter 4.2 mm and length 11.5 mm was inserted. Healing screw was placed on the implant body and flap repositioned, and sutures placed. Radiographic examination revealed that the two implant placed were slightly divergent which will be compensated using the locator attachment [Figure 2] and [Figure 3].
Figure 2: Implant placement

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Figure 3: Postoperative radiograph

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Second-stage surgery and loading protocol

Twelve weeks postoperatively osseointegration was evaluated clinically as well as radiographically and implants were found rigidly fixed with an adequate zone of healthy, keratinized gingiva without any sign of crestal bone loss. The second-stage surgery was performed. The implants cover screws were removed, and healing abutment were screwed into the implant body.

Prosthetic phase

Healing abutments removed and the locator abutments were tightened with a hand rachet and impression copings placed [Figure 4]. The impression was then registered using “close-tray impression technique” with polyvinyl siloxane impression material. The abutment analogs were then snapped into the impression copings retained inside the set impression, and the impression was poured in Type-IV dental stone to fabricate the master cast. On separation, the locator abutment analog is part of the master cast replicating the position of the Locator Implant Abutment in the oral cavity. The subsequent steps of face-bow transfer, jaw relation record, teeth setting, and try-in of the mandibular denture were accomplished in consistent with the standard method of complete denture fabrication. After the boil-out, during processing of the denture, the white Block-Out Spacers of the locator attachment system were placed over the head of each corresponding abutment analog followed by the placement of a metallic cap with Black Processing Male over it [Figure 5], [Figure 6], [Figure 7], [Figure 8]. The white spacers were discarded from the processed denture, and the finishing and polishing of the denture were completed. The locator male removal component of the locator core tool was used to remove the black nylon processing male from the metal cap. The locator male seating tool was then used to firmly push the selected blue replacement males into each of two empty metal caps in the denture individually. The denture was placed in patient's mouth, and the attachments were found engaged. The flanges and occlusion were adjusted as needed. The patient was instructed as for routine denture and oral hygiene maintenance [Figure 9].
Figure 4: Locator abutments

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Figure 5: Closed tray impression

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Figure 6: Master cast with analog

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Figure 7: Black processing male

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Figure 8: Final blue retentive male

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Figure 9: Postoperative intraoral view in occlusion

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Posttreatment evaluation

The patient was recalled at 2-week, 1-month, 3-month, and 6-month follow-up appointments. Oral hygiene instructions were reviewed. Oral hygiene was excellent. The patient was delighted with the adequate retention, stability, comfort, and function of the mandibular implant-retained overdenture to his complete satisfaction. The occlusion was found stable; the denture and attachments were clean. The attachment system was devoid of any sign of wearing during the period.

   Discussion Top

Indications of implant overdenture are advanced atrophy of alveolar bone eliminating the potential for full arch implant-supported prosthesis, cases where augmentation procedures are contraindicated, possess natural teeth in the opposing arch, elderly patients who have lost their motor skills and no longer feel able to wear conventional complete dentures, compromised conventional denture retention, for example, xerostomia, bruxism, and maxillofacial resection defects.[9]

Studies revealed that the two-implant supported overdenture therapy can be considered as a very reliable treatment for patients with an edentulous mandible, so they should be the standard treatment modality for full edentulous patients suffering from discomfort with their conventional denture.[10],[11],[12] A systematic review concluded that the survival rates of implants and overdentures and patient satisfaction with a maxillary overdenture supported by four implants were not influenced by the overdenture design, and no statistical difference was detected between the splinted and unsplinted groups.[13]

Immediate or early loading protocols for the edentulous mandible offer the patient with many advantages in terms of decreased number of visits, early functional recovery, and reduction of surgical exposure.[14] However, this treatment option is not universally appropriate for all patients; delayed loading of prosthesis is expected to show better results in those cases. Implant can be placed either by 1-stage procedure or 2-stage procedures. If the optimal implant stability is not achieved or if there is a risk that the transitional denture transmits excessive forces to the implants, the 2-stage procedure could be preferable. We conducted 2-stage submerged implants in this case with delayed loading.[15]

Latest studies also reveal that Locator attachments with different retentive forces had a significant effect on the denture stability of two implant-retained mandibular overdenture.[16] Locator attachments are recommended over Dolder bar attachments, as Locator attachments were associated with high retention and stability after wear simulation with minimal retention loss.[17] Locator system also showed superior clinical results than the ball and the bar attachments with regard to the rate of prosthodontic complications and the maintenance of the oral function.[18]

   Conclusion Top

The implant-supported overdenture is a very interesting option in the treatment of patients with moderate-to-severe resorbed mandible. It offers the advantages of removable prostheses as well as the stability and retention of a fixed prosthesis.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Carlsson GE. Clinical morbidity and sequelae of treatment with complete dentures. J Prosthet Dent 1998;79:17-23.  Back to cited text no. 1
Kreisler M, Behneke N, Behneke A, D'Hoedt B. Residual ridge resorption in the edentulous maxila in patients with implant-supported mandibular overdentures: An 8-years retrospective study. Int J Prosthodont 2003;16:265-300.  Back to cited text no. 2
Carlsson GE. Responses of jawbone to pressure. Gerodontology 2004;21:65-70.  Back to cited text no. 3
Campbell RL. A comparative study of the resorption of the alveolar ridges in denture-wearers and non-denture-wearers. J Am Dent Assoc 1960;60:143-53.  Back to cited text no. 4
Khalid T, Yunus N, Ibrahim N, Saleh NB, Goode D, Masood M. Assessment of masticatory function of mandibular implant-supported overdenture wearers: A 3-year prospective study. J Prosthet Dent 2020;124:674-81.  Back to cited text no. 5
Salinas TJ. Implant Prostthodontics. In: Miloro M, Ghali GE, Larsen PE, Waite PD, editors. Peterson's Principles of Oral And Maxillofacial Surgery. London: BC Decker Inc Hamilton; 2004. p. 263.  Back to cited text no. 6
Ünlü Kurşun B, Akan E. Radiographic determination of trabecular bone change in 2- and 4-implant-supported overdenture prostheses. Oral Surg Oral Med Oral Pathol Oral Radiol 2021;131:364-70.  Back to cited text no. 7
Kuoppala R, Näpänkangas R, Raustia A. Outcome of implant-supported overdenture treatment – A survey of 58 patients. Gerodontology 2012;29:e577-84.  Back to cited text no. 8
Mericske-Stern RD, Taylor TD, Belser U. Management of the edentulous patient. Clin Oral Implants Res 2000;11 Suppl 1:108-25.  Back to cited text no. 9
Feine JS, Carlsson GE, Awad MA, Chehade A, Duncan WJ, Gizani S, et al. The McGill consensus statement on overdentures. Mandibular two-implant overdentures as first choice standard of care for edentulous patients. Gerodontology 2002;19:3-4.  Back to cited text no. 10
Vercruyssen M, Marcelis K, Coucke W, Naert I, Quirynen M. Long-term, retrospective evaluation (implant and patient-centred outcome) of the two-implants-supported overdenture in the mandible. Part 1: Survival rate. Clin Oral Implants Res 2010;21:357-65.  Back to cited text no. 11
Thomason JM, Kelly SA, Bendkowski A, Ellis JS. Two implant retained overdentures – A review of the literature supporting the McGill and York consensus statements. J Dent 2012;40:22-34.  Back to cited text no. 12
Di Francesco F, De Marco G, Sommella A, Lanza A. Splinting vs. not splinting four implants supporting a maxillary overdenture: A systematic review. Int J Prosthodont 2019;32:509-18.  Back to cited text no. 13
Hong JW, Ahn SG, Leem DH, Seo JM. Immediate placement and functional loading of implants on canine with fixed partial denture for a patient having canine protected occlusion: A case report. J Adv Prosthodont 2012;4:52-6.  Back to cited text no. 14
Esposito M, Grusovin MG, Willings M, Coulthard P, Worthington HV. Interventions for replacing missing teeth: Different times for loading dental implants. Cochrane Database Syst Rev 2007;8:CD003878.  Back to cited text no. 15
Liu W, Zhang X, Qing H, Wang J. Effect of LOCATOR attachments with different retentive forces on the stability of 2-implant-retained mandibular overdenture. J Prosthet Dent 2020;124:224-9.  Back to cited text no. 16
ELsyad MA, Dayekh MA, Khalifa AK. Locator versus bar attachment effect on the retention and stability of implant-retained maxillary overdenture: An in vitro study. J Prosthodont 2019;28:e627-36.  Back to cited text no. 17
Cakarer S, Can T, Yaltirik M, Keskin C. Complications associated with the ball, bar and Locator attachments for implant-supported overdentures. Med Oral Patol Oral Cir Bucal 2011;16:e953-9.  Back to cited text no. 18


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9]


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