Journal of Prosthetic Dentistry
Systematic Review| Volume 128, ISSUE 6, P1211-1220, December 2022

Download started.


Effect of the attachments on clinical outcomes of mandibular distal extension implant-supported removable partial dentures: A systematic review


      Statement of problem

      Healing abutments and attachments have been used for implant-supported removable partial dentures (ISRPDs). However, the effects of these abutments and attachments on the clinical outcomes of the implants and prostheses are elusive because of the lack of standardized research protocols.


      The purpose of this systematic review was to determine the clinical outcomes of mandibular distal extension ISRPDs with healing abutments and attachments by analyzing qualified studies.

      Material and methods

      An electronic and manual literature search was conducted on PubMed, Web of Science, Scopus, Embase, and Cochrane Library databases including articles published in English from 1980 to 2020. Publications of clinical outcome studies on the mandibular distal extension ISRPDs with healing abutments or attachments were screened by inclusion and exclusion criteria. Clinical outcomes of removable partial dentures (RPDs) and ISRPDs with different types of abutments or attachments were compared by using patient-reported outcome measures, implant survival rate, masticatory performance, and implant- or prosthesis-related complications. Study designs and clinical outcome data were extracted and analyzed. The evidence of the selected studies and degree of recommendation were made according to the Oxford Centre for Evidence-based Medicine, and the risk of bias of the studies was assessed based on Newcastle-Ottawa criteria.


      Of 541 articles initially identified after removing duplicate records, 11 articles were selected by applying the inclusion and exclusion criteria, by inter-viewer agreement, and by hand searching. Nine prospective cohort studies, 1 retrospective cohort study, and 1 randomized controlled trial were included with evidence levels assessed at 1b, 2b, and 2c. The risk of bias varied from 5 to 8 out of 9. Patient overall satisfaction, oral health–related quality of life (OHRQoL) scores, and masticatory ability were significantly improved for ISRPDs with either healing abutments, ball, or LOCATOR attachments when compared with RPDs. The implant survival rate varied from 92% to 97% at 2 to 10 years for ball attachment and was 100% at 1 year for LOCATOR attachment-supported ISRPDs. Marginal bone loss (MBL) varied from 0 to 1 mm in all studies, although LOCATOR attachments had significantly less MBL compared with ball attachments. The maximal pocket depth and bleeding on probing index around implants at 1 year were 1.7 to 1.8 mm and 0.1 to 0.3. Loose healing caps were the main mechanical complication of implants. There were more prosthetic complications in ISRPDs with ball attachments than RPDs at 10-year follow-up, including gold matrix loosening, loss of retention, and denture base fractures. No direct comparisons were made of patient-reported outcomes or prosthetic complications between ball and LOCATOR attachment-supported ISRPDs.


      Healing abutments and attachments (ball or LOCATOR) improved patient-reported outcomes and the masticatory function of mandibular distal extension ISRPDs. However, insufficient evidence was found to determine the relative effectiveness of different attachment systems on the clinical outcomes of mandibular distal extension ISRPDs. Abutment loosening was the most frequent mechanical complication for healing abutments. More prosthetic complications were associated with ball attachment-supported ISRPDs than RPDs. The major weaknesses of this systematic review were the relatively moderate level of evidence and the publication language, since implant attachments are used in many non-English speaking countries.
      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Journal of Prosthetic Dentistry
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Goodkind R.J.
        The effects of removable partial dentures on abutment tooth mobility: a clinical study.
        J Prosthet Dent. 1973; 30: 139-146
        • Phoenix R.D.
        • Cagna D.R.
        • DeFreest C.F.
        • Funk K.
        Stewart’s clinical removable partial prosthodontics.
        4th ed. Quintessence, Chicago2008: 19-205
        • Brown A.C.D.
        McCracken’s removable partial prosthodontics.
        12th ed. Mosby, St. Louis2010: 115-129
        • Frank R.P.
        • Milgrom P.
        • Leroux B.G.
        • Hawkins N.R.
        Treatment outcomes with mandibular removable partial dentures: a population-based study of patient satisfaction.
        J Prosthet Dent. 1998; 80: 36-45
        • Brudvik J.S.
        Advanced removable partial dentures.
        1st ed. Quintessence, Chicago1999: 153-160
        • Schneid T.R.
        • Mattie P.A.
        • Phoenix R.D.
        • Cagna D.R.
        • DeFreest C.F.
        • Funk K.
        Stewart’s clinical removable partial prosthodontics.
        4th ed. Quintessence, Chicago2008: 259-278
        • Shahmiri R.A.
        • Atieh M.A.
        Mandibular Kennedy class I implant-tooth-borne removable partial denture: a systematic review.
        J Oral Rehabil. 2010; 37: 225-234
        • de Freitas R.F.
        • de Carvalho Dias K.
        • da Fonte Porto Carreiro A.
        • Barbosa G.A.
        • Ferreira M.A.
        Mandibular implant-supported removable partial denture with distal extension: a systematic review.
        J Oral Rehabil. 2012; 39: 791-798
        • Zancopé K.
        • Abrão G.M.
        • Karam F.K.
        • Neves F.D.
        Placement of a distal implant to convert a mandibular removable Kennedy class I to an implant-supported partial removable Class III dental prosthesis: A systematic review.
        J Prosthet Dent. 2015; 113: 528-533
        • Park J.H.
        • Lee J.Y.
        • Shin S.W.
        • Kim H.J.
        Effect of conversion to implant-assisted removable partial denture in patients with mandibular Kennedy classification: a systematic review and meta-analysis.
        Clin Oral Implants Res. 2020; 31: 360-373
        • Jensen C.
        • Meijer H.J.A.
        • Raghoebar G.M.
        • Kerdijk W.
        • Cune M.S.
        Implant-supported removable partial dentures in the mandible: a 3-16 year retrospective study.
        J Prosthodont Res. 2017; 61: 98-105
        • Bortolini S.
        • Natali A.
        • Franchi M.
        • Coggiola A.
        • Consolo U.
        Implant-retained removable partial dentures: an 8-year retrospective study.
        J Prosthodont. 2011; 20: 168-172
        • Payne A.G.
        • Tawse-Smith A.
        • Wismeijer D.
        • De Silva R.K.
        • Ma S.
        Multicentre prospective evaluation of implant-assisted mandibular removable partial dentures: surgical and prosthodontic outcomes.
        Clin Oral Implants Res. 2017; 28: 116-125
        • Kaufmann R.
        • Friedli M.
        • Hug S.
        • Mericske-Stern R.
        Removable dentures with implant support in strategic positions followed for up to 8 years.
        Int J Prosthodont. 2009; 22: 233-241
        • Bahrami M.
        • Alsharbaty M.H.M.
        Prospective clinical study of prosthetic treatment outcome of implant-retained-removable-partial-denture during 5 year-follow-ups.
        Australas Med J. 2017; 10: 927-933
        • Grossmann Y.
        • Levin L.
        • Sadan A.
        A retrospective case series of implants used to restore partially edentulous patients with implant-supported removable partial dentures: 31-month mean follow-up results.
        Quintessence Int. 2008; 39: 665-671
        • Mijiritsky E.
        • Lorean A.
        • Mazor Z.
        • Levin L.
        Implant tooth-supported removable partial denture with at least 15-year long-term follow-up.
        Clin Implant Dent Relat Res. 2015; 17: 917-922
        • Chvartszaid D.
        Commentary: Removable dentures with implant support in strategic positions followed for up to 8 years.
        Int J Prosthodont. 2009; 22: 242
        • Payne A.G.
        • Alsabeeha N.H.
        • Atieh M.A.
        • Esposito M.
        • Ma S.
        • Anas El-Wegoud M.
        Interventions for replacing missing teeth: attachment systems for implant overdentures in edentulous jaws.
        Cochrane Database Syst Rev. 2018; 10: Cd008001
        • Gonçalves F.
        • Campestrini V.L.L.
        • Rigo-Rodrigues M.A.
        • Zanardi P.R.
        Effect of the attachment system on the biomechanical and clinical performance of overdentures: a systematic review.
        J Prosthet Dent. 2020; 123: 589-594
        • Liberati A.
        • Altman D.G.
        • Tetzlaff J.
        • Mulrow C.
        • Gøtzsche P.C.
        • Ioannidis J.P.A.
        • et al.
        The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration.
        J Clin Epidemiol. 2009; 62: e1-e34
        • Schardt C.
        • Adams M.B.
        • Owens T.
        • Keitz S.
        • Fontelo P.
        Utilization of the PICO framework to improve searching PubMed for clinical questions.
        BMC Med Inform Decis. 2007; 7: 16
        • Howick J.
        • Chalmers I.
        • Glasziou P.
        • Greenhalgh T.
        • Heneghan C.
        • Liberati A.
        • et al.
        Explanation of the 2011 Oxford Centre for Evidence-Based Medicine (OCEBM) levels of evidence (background document) [Internet].
        Oxford Centre for Evidence-Based Medicine, Oxford2016
        • Wells G.A.
        • Shea B.
        • O'Connell D.
        • Peterson J.
        • Welch V.
        • Losos M.
        • et al.
        The Newcastle–Ottawa Scale (NOS) for assessing the quality of non-randomized studies in meta-analysis [Internet].
        Ottawa Hospital Research Institute, Ottawa2011
        • Campos C.H.
        • Goncalves T.M.
        • Garcia R.C.
        Implant-supported removable partial denture improves the quality of life of patients with extreme tooth loss.
        Braz Dent J. 2015; 26: 463-467
        • Gates W.D.
        • Cooper L.F.
        • Sanders A.E.
        • Reside G.J.
        • De Kok I.J.
        The effect of implant-supported removable partial dentures on oral health quality of life.
        Clin Oral Implants Res. 2014; 25: 207-213
        • Goncalves T.M.
        • Campos C.H.
        • Garcia R.C.
        Implant retention and support for distal extension partial removable dental prostheses: satisfaction outcomes.
        J Prosthet Dent. 2014; 112: 334-339
        • Goncalves T.M.
        • Campos C.H.
        • Garcia R.C.
        Mastication and jaw motion of partially edentulous patients are affected by different implant-based prostheses.
        J Oral Rehabil. 2014; 41: 507-514
        • Jensen C.
        • Speksnijder C.M.
        • Raghoebar G.M.
        • Kerdijk W.
        • Meijer H.J.A.
        • Cune M.S.
        Implant-supported mandibular removable partial dentures: functional, clinical and radiographical parameters in relation to implant position.
        Clin Implant Dent Relat Res. 2017; 19: 432-439
        • Jensen C.
        • Raghoebar G.M.
        • Kerdijk W.
        • Meijer H.J.
        • Cune M.S.
        Implant-supported mandibular removable partial dentures; patient-based outcome measures in relation to implant position.
        J Dent. 2016; 55: 92-98
        • Mously H.A.
        Effect of two implant-supported partial overdenture attachment design on the periodontal health.
        J Contemp Dent Pract. 2020; 21: 68-72
        • Mahrous A.I.
        • Aldawash H.A.
        • Soliman T.A.
        • Banasr F.H.
        • Abdelwahed A.
        Implant supported distal extension over denture retained by two types of attachments. A comparative radiographic study by cone beam computed tomography.
        J Int Oral Health. 2015; 7: 5-10
        • Wismeijer D.
        • Tawse-Smith A.
        • Payne A.G.
        Multicentre prospective evaluation of implant-assisted mandibular bilateral distal extension removable partial dentures: patient satisfaction.
        Clin Oral Implants Res. 2013; 24: 20-27
        • Elsyad M.A.
        • Habib A.A.
        Implant-supported versus implant-retained distal extension mandibular partial overdentures and residual ridge resorption: a 5-year retrospective radiographic study in men.
        Int J Prosthodont. 2011; 24: 306-313
        • Pihlstrom B.L.
        • Barnett M.L.
        Design, operation, and interpretation of clinical trials.
        J Dent Res. 2010; 89: 759-772
        • Mitrani R.
        • Brudvik J.S.
        • Phillips K.M.
        Posterior implants for distal extension removable prostheses: a retrospective study.
        Int J Periodontics Restorative Dent. 2003; 23: 353-359
        • Ohkubo C.
        • Kobayashi M.
        • Suzuki Y.
        • Hosoi T.
        Effect of implant support on distal-extension removable partial dentures: in vivo assessment.
        Int J Oral Maxillofac Implants. 2008; 23: 1095-1101
        • Suzuki Y.
        • Kono K.
        • Shimpo H.
        • Sato Y.
        • Ohkubo C.
        Clinical evaluation of implant-supported removable partial dentures with a stress-breaking attachment.
        Implant Dent. 2017; 26: 516-523
        • Guédat C.
        • Nagy U.
        • Schimmel M.
        • Müller F.
        • Srinivasan M.
        Clinical performance of LOCATOR® attachments: a retrospective study with 1-8 years of follow-up.
        Clin Exp Dent Res. 2018; 4: 132-145
        • Minoretti R.
        • Triaca A.
        • Saulacic N.
        The use of extraoral implants for distal-extension removable dentures: a clinical evaluation up to 8 years.
        Int J Oral Maxillofac Implants. 2009; 24: 1129-1137
        • Bidra A.S.
        • Daubert D.M.
        • Garcia L.T.
        • Kosinski T.F.
        • Nenn C.A.
        • Olsen J.A.
        • et al.
        Clinical practice guidelines for recall and maintenance of patients with tooth-borne and implant-borne dental restorations.
        J Am Dent Assoc. 2016; 147: 67-74