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Year : 2017  |  Volume : 8  |  Issue : 2  |  Page : 48-51

Using individual two-posterior short implants with two-anterior standard implants in mandibular implant-supported-overdenture to enhance the patient satisfaction: A clinical report

1 Dental Research Center, Department of Prosthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
2 Department of Prosthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran

Date of Web Publication11-May-2017

Correspondence Address:
Mohammed Hussein M Alsharbaty
Dental Research Center, Department of Prosthodontics, School of Dentistry, Tehran University of Medical Sciences, Kargar Street, Tehran
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2155-8213.206104

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Introduction: Many clinical cases and the literature review have revealed implant-supported-overdentures’ (ISOs) treatment success and predictability in elderly patients. According to the previous studies, all the mandibular ISOs used 2–4 implants anterior to mental foramen to retain the denture. Case Report: In this clinical report, two individual anterior standard implants and two individual posterior short implants were used to support the mandibular ISO, as well as to prevent further posterior bone resorption. This treatment option permits the patient to insert more implants in the future, and could be upgraded to implant-supported-fixed prosthesis. Discussion: The patient was completely satisfied about the final result, especially for upgrading the mastication efficiency. The patient was followed-up for more than 2 years without complication. The panoramic X-ray showed the preserved bone in the posterior region. This technique could be considered to be innovative, and more clinical cases are required to be documented as a predictable modality.

Keywords: Dental implants, denture precision attachments, implant-supported-denture prosthesis

How to cite this article:
Bahrami M, Alsharbaty MM. Using individual two-posterior short implants with two-anterior standard implants in mandibular implant-supported-overdenture to enhance the patient satisfaction: A clinical report. Dent Hypotheses 2017;8:48-51

How to cite this URL:
Bahrami M, Alsharbaty MM. Using individual two-posterior short implants with two-anterior standard implants in mandibular implant-supported-overdenture to enhance the patient satisfaction: A clinical report. Dent Hypotheses [serial online] 2017 [cited 2023 Mar 22];8:48-51. Available from:

  Introduction Top

Edentulous patients frequently suffer from difficulties with mandibular complete dentures. Inefficient support, retention, and stability of the mandibular dentures, accompanied by diminished masticating capacity, are the main complaints in such patients.[1] Conventional treatment options for completely edentulous patients commonly show functional imperfections, and are often associated with psychosocial restrictions.[2],[3] A regularly used treatment option to resolve mandibular denture problems is to place endosseous implants in the mandible to support or retain an overdenture. Engquist et al. published one of the first studies regarding overdentures supported by endosseous implants in 1988.[4] After approximately three decades, this treatment modality is still noteworthy in the rehabilitation of edentulous patients, and is documented as a reliable and cost-effective treatment option.[5],[6],[7] The survival rate of dental implants, either placed as a one- or two-stage procedure, applied to support a mandibular overdenture in a moderately resorbed edentulous mandible, has been exhibited to be successful in over 95% of all cases in the literature with a 5–10-year follow-up.[8],[9] According to the available evidence, usually 2–4 implants are used in the mandibular anterior segment to fabricate ISOs. Inserting implants posterior to mental foramen with anterior implants splinted together to fabricate full-arch prosthesis was not considered as a treatment of choice. Because of the dynamic mandibular movements caused by the flexion and the torsion during opening, protrusive, and parafunction movements. The most common complication of using mandibular full-arch splinted implants prosthesis is pain upon opening. Although many studies have reported such complications, using two implants in anterior segment with another two implants in the posterior segment could preserve the bone in the posterior region from further resorption. When using only anterior implants to construct ISOs, posterior bone resorption might be reduced; however, several years later, bone resorption could be noticed. Another benefit of inserting anterior and posterior implants would allow the patients to insert two or more implants in the future and fabricating fixed prosthesis. Conversely when implants were not inserted in the posterior segment further resorption could be seen, which could impede the insertion of more implants to fabricate fixed denture. The previous studies have evaluated the mandibular full-arch prostheses complications due to the flexion and torsion in fixed dentures; however, the situation is different with removable dentures because of the acrylic resiliency during dynamic mandibular movements. The purpose of this clinical report is to introduce a new practice for fabricating implant-supported overdenture (ISO) with individual two anterior standard implants and two posterior short implants in mandibular arch.

  Case Report Top

A 61-year-old male patient presented to the prosthodontics department in Tehran University of Medical Sciences (TUMS) who complained regarding previous mandibular conventional complete denture because of tissue displacement, denture loosening, and inefficient mastication. After intraoral and radiographic examinations, the recommendation was for dental implants placement and fixed prosthesis fabrication; however, the patient had some financial problems that could not afford this option. Another treatment option was discussed with the patient to insert four implants and fabricate ISO. The clinical decision was to insert two standard lengths implants in the anterior mandible, and another two short implants in the posterior mandible with four unsplinted resilient attachments to provide the level of resilience required for implant-supported and tissue-supported denture. Two standard length implants were inserted in #33 and #42 (Implantium/Dentium system, Seoul, South Korea, 3.6 × 12 mm, internal hexagon). One short implant in #46 (Implantium/Dentium system, Seoul, South Korea 5 × 8 mm, internal hexagon), and another one in #36 (Implantium/Dentium system, Seoul, South Korea 4.5 × 8 mm, internal hexagon) have been placed [Figure 1]. Two-stage surgery was performed. Four months after implants insertion, primary impression with irreversible hydrocolloid (TAKE 1 Alginate, Kerr, Orange, California, USA) was taken. Customized tray was fabricated and open-tray impression copings were placed, hand tightened, and verified with periapical X-ray for proper seating. Open-tray final impression technique was made with medium-viscosity monophase AS (Panasil Monophase, Kettenbach GmbH, Eschenburg, Germany). The record base was fabricated and bite registration record was taken. In the next appointment, the teeth arrangement were tried-in. The inter-occlusal-space (IOS) was measured on the casts with a periodontal probe using the putty-silicon-index (Speedex, Colten/Whaledent Inc, Cuyahoga Falls, Ohio, USA); it was 11 mm between the two arches. Four individual equator abutments were selected to support the prosthesis (OT Equator, Rhein83, New Rochelle, New York, USA). Reinforcement metal framework was constructed to prevent the potential fracture of the denture caused by minimal acrylic thickness or excessive occlusal forces. During the delivery procedure, the equator attachments were seated intraorally [Figure 2], and torqued according to the manufacturer’s instructions (25 Panoramic radiograph was obtained to confirm the complete seating of the abutments [Figure 3]. The elastic O-rings were placed inside the metal housings of the prosthesis [Figure 4]. The prosthesis was inserted in the patient’s mouth [Figure 5]. The occlusal scheme was bilateral-balanced-occlusion. The patient was followed-up for more than 2 years [Figure 6] and [Figure 7] with no pain or other complications and just recalled for plastic caps replacement.
Figure 1: Panoramic view after implants insertion

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Figure 2: Four OT Equator attachments placed intra-orally

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Figure 3: Panoramic view after complete seating of the abutments

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Figure 4: Intaglio surface of mandibular prosthesis

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Figure 5: Intra-oral view after prosthesis delivery

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Figure 6: Panoramic view after 2-year follow-up

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Figure 7: Intra-oral view after 2-year follow-up

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  Discussion Top

Treatment outcome with mandibular ISO was found to be predictable and satisfactory treatment modality for elderly patients, and was successful in long-term follow-up studies. The tendency to use short implants was raised after the evolution of the “crestal load focus” phenomenon. It was shown that, when implants are loaded, most stresses are concentrated within the crestal 7–9 mm of the bony ridge. Short implants could be considered as an advantageous option because extensive bone augmentation procedure implicates higher morbidity, is more time consuming, and entails higher cost to the patients.[10] Several studies have been published proposing that short implants (≤8 or <10 mm) have similar survival rate and efficacy compared to the placement of standard implants (≥10 mm). One randomized clinical trial study compared the three options of implants supporting an overdenture in extremely resorbed mandible. First option is to reconstruct the mandible with autologous bone grafts and then four implants insertion. The second option is the use of transmandibular implants. The third option is to place only four short implants in severely resorbed mandible.[10] After 2 years of assessment, no implants failed in the short implants group, and the authors concluded that placement of short implants is the most promising treatment option. In this case, two anterior and two posterior implants have been used to retain the ISO. This option allows the patient to insert more implants later and fabricating fixed prosthesis, and can preserve the bone in the posterior region from further resorption. Because the denture base acrylic has some degree of resiliency about (1229.68 MPa) the mean elastic modulus, and the resilient O-rings have been used, which provide cushion effect, the patient did not express any pain or complication. In general, ISOs treatment provides simple, predictable, and cost-effective option to edentulous patients.

  Conclusion Top

In this article the clinical steps of fabricating mandibular ISO with individual two standard and two short dental implants have been presented. The final result was acceptable, and the patient was completely satisfied, especially with masticatory efficiency. This clinical technique was first tried in this case with more than 2 years of follow-up. Further clinical cases with more follow-up duration are needed to confirm the durability of such treatments, and should be documented for future routine clinical work.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Van Waas MA. The influence of clinical variables on patients’ satisfaction with complete dentures. J Prosthet Dent 1990;63:307-10.  Back to cited text no. 1
Carlsson GE, Omar R. The future of complete dentures in oral rehabilitation. A critical review. J Oral Rehabil 2010;37:143-56.  Back to cited text no. 2
Fiske J, Davis D, Frances C, Gelbier S. The emotional effects of tooth loss in edentulous people. Br Dent J 1998;184:90-3.  Back to cited text no. 3
Engquist B, Bergendal T, Kallus T, Linden U. A retrospective multicenter evaluation of osseointegrated implants supporting overdentures. Int J Oral Maxillofac Implants 1988;3.  Back to cited text no. 4
Meijer HJ, Raghoebar GM, Van‘t Hof MA. Comparison of implant-retained mandibular overdentures and conventional complete dentures: A 10-year prospective study of clinical aspects and patient satisfaction. Int J Oral Maxillofac Implants 2003;18.  Back to cited text no. 5
Raghoebar G, Meijer H, Vant Hof M, Stegenga B, Vissink A. A randomized prospective clinical trial on the effectiveness of three treatment modalities for patients with lower denture problems: A 10 year follow-up study on patient satisfaction. Int J Oral Maxillofac Implants 2003;32:498-503.  Back to cited text no. 6
Meijer HJ, Raghoebar GM, Batenburg RH, Visser A, Vissink A. Mandibular overdentures supported by two or four endosseous implants: A 10-year clinical trial. Clin Oral Implants Res 2009;20:722-8.  Back to cited text no. 7
Batenburg RH, Raghoebar GM, Van Oort RP, Heijdenrijk K, Boering G. Mandibular overdentures supported by two or four endosteal implants: A prospective, comparative study. Int J Oral Maxillofac Implants 1998;27:435-9.  Back to cited text no. 8
Stoker G, Wismeijer D, Van Waas M. An eight-year follow-up to a randomized clinical trial of aftercare and cost-analysis with three types of mandibular implant-retained overdentures. J Dent Res 2007;86:276-80.  Back to cited text no. 9
Stellingsma K, Raghoebar GM, Stegenga B. The extremely resorbed mandible: A comparative prospective study of 2-year results with 3 treatment strategies. Int J Oral Maxillofac Implants 2004;19.  Back to cited text no. 10


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


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