Long-term outcomes of three types of implant-supported mandibular overdentures in smokers

Department of Oral Implantology and Prosthodontics, Academic Centre for Dentistry Amsterdam, Research Institute MOVE, University of Amsterdam and Free University, Amsterdam, The Netherlands.
Clinical Oral Implants Research (Impact Factor: 3.89). 07/2011; 23(8):925-9. DOI: 10.1111/j.1600-0501.2011.02237.x
Source: PubMed


The aim of the study was to compare the differences in the long-term clinical and radiologic effects for three different treatment strategies with implant-supported overdentures in the edentulous mandible, with a special emphasis on smoking.
In a randomized- controlled clinical trial, 110 edentulous patients participated. Thirty-six patients were treated with an overdenture supported by two implants with ball attachments (2IBA), 37 patients with an overdenture supported by two implants with a bar (2ISB) and 37 patients with an overdenture supported by four implants with a triple bar (4ITB). After a mean evaluation period of 8.3 years, the clinical and radiographic parameters were evaluated.
Ninety-four out of the original 110 patients (=85%) were evaluated. In the 2IBA group, the plaque index was significantly lower (vs. 2ISB, P=0.013; vs. 4ITB, P=0.001) than in the other groups, but there was no correlation with the other peri-implant parameters. In the 4ITB group, the marginal bone loss was significantly higher than that in the two implant groups. The maximal probing depth was correlated with peri-implant bone loss (P=0.011). Smoking almost doubled marginal bone loss irrespective of the treatment strategy chosen.
Patients with two implants show less marginal bone loss than those with four implants. Smoking is a risk factor for the survival of dental implants in the long run.

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    • "c o m / j o u r n a l s / j d e n Although initial reports suggested increased failure rates for implants supporting an overdenture, compared to partial/full fixed bridges (for review see Berglundh et al. [18]), more recent clinical trials clearly proved the opposite. The cumulative survival rate for implants supporting a mandibular overdenture remains above 96% after 10 years, with minimal marginal bone loss [19] [20] [21] [22]. A variety of attachment systems is available for mandibular overdentures: ball attachments, bar attachments, or other attachment systems (e.g., magnets). "
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    ABSTRACT: Fractures of distal bar extensions, supporting a mandibular overdenture, do occur with significant functional and economic consequences for the patient. This study therefore aims to evaluate the effect of different bar cross-sectional shapes and surfaces, bar extension lengths and the placement of a support rib under the distal bar extension on fracture resistance. The 2nd moment area and static strength were calculated for 11 frequently used bar designs using finite element analysis (FEA). For two specific designs (Ackermann round 1.8 mm and Dolder Y-macro, the former with and without a support rib) additional physical static and fatigue strength tests were included. The FEA static strength data corresponded well to the 2nd moment area (a similar ranking when maximum allowed force was considered). The application of a rib support (Ackermann 1.8 mm) and limitations of the bar extension length (6 mm for the Ackermann 1.8 mm, 8 mm for the Dolder Y-macro) allowed the bars to exceed 5 × 10(6) cycles of 120 and 250 N respectively, before fracture. The region of highest stresses in FEA corresponded well with the locations of the fractures observed in static- and fatigue testing. With some simple guidelines/modifications, the number of bar extension fractures can be reduced significantly. This study focusses on distal bar extensions which improve the positioning of an implant supported overdenture. By combining laboratory testing and finite element simulations we aim to: (1) explain why fractures occur (dependent on physical characteristics of the bar), and (2) give clinical guidelines on how to prevent such fractures. Copyright © 2015. Published by Elsevier Ltd.
    Journal of dentistry 06/2015; 43(9). DOI:10.1016/j.jdent.2015.06.007 · 2.75 Impact Factor
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    • "Prospective cohort/5 years " Evaluate clinically and radiographically immediate implants " 22/68 Mucositis: PPD ≥4 mm+ BoP Peri-implantitis: PPD ≥4 mm+BoP+ " significant bone loss " Implants: 20 % (P) Implants: 5.8 % (P) Comment: " Implants placed with the immediate protocol demonstrated a higher tendency to crestal bone loss and periimplantitis " NS Table 1 (continued) References Study design/follow-up Aim Sample size (patients/implants) Disease definition Prevalence (P) of mucositis Prevalence (P)/incidence (I) of peri-implantitis Stoker et al. 2012 [38] Prospective RCT/8.3 years " Compare the differences in the long-term clinical and radiologic effects for three different treatment strategies with implant-supported overdentures in the edentulous mandible, with a special emphasis on smoking " 94/256 No clear definition (clinical signs of inflammation not recorded) Patients: 5 % (P) Implants: 5 % (P) Comment: " smoking almost doubled marginal bone loss " Östman et al. 2012 [40] "
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    ABSTRACT: This narrative review focuses on the current understanding of the definition and prevalence of peri-implantitis. A MEDLINE (PubMed) search over the past 3 years was performed using keywords related to the definition and prevalence of peri-implantitis. Additional literature retrieved from reference lists, review articles, and consensus reports were used. Definition of peri-implantitis is heterogeneous due to the various thresholds of bone loss and pocket depths used, creating a discrepancy in the prevalence figures. The prevalence of peri-implant mucositis varied between 19 and 65 %, whereas the prevalence of peri-implantitis ranged from 10 to 40 %. A consensus has been reached that the definition of peri-implantitis should be clinical signs of inflammation (bleeding on probing) and/or suppuration, in combination with progressive bone loss. In addition, we strongly recommend that measurement of the bone loss in relation to the implant length would further classify the case as mild, moderate, or severe peri-implantitis.
    12/2014; 1(4). DOI:10.1007/s40496-014-0031-x

  • Peri-Implant Tissue Remodeling: Scientific Background and Clinical Implications, 1 edited by Luigi Canullo, Roberto Cocchetto, Ignazio Loi, 01/2012: chapter Factors Affecting Peri-Implant Bone Remodeling; Quintessence Publishing.
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