Photoelastic stress analysis of various retention mechanisms on 3-implant-retained mandibular overdentures.

STATEMENT OF PROBLEM There are various stress transfer studies of 2- or 4-implant-retained mandibular overdenture designs. However, the influence of various types of attachments and implant inclination on stress distribution of 3-implant-retained mandibular overdenture designs has not been sufficiently assessed. PURPOSE The purpose of this study was to compare the load transfer characteristics of 4 attachment systems for 3-implant-retained mandibular overdenture designs for vertically oriented and inclined implants. MATERIAL AND METHODS Two photoelastic mandibular models were fabricated having 3 screw-type implants (3.7 x 14 mm with 4.8-mm diameter abutment platform) embedded in the interforaminal region. In the first model, the implants were parallel to each other and vertically oriented. In the second model, 1 implant in the midline was vertically oriented, and the other 2 implants were positioned 20 degrees divergent from the center implant. Four retention mechanisms were studied for each model--the Locator, Swissplus ball, Bredent bar, and Bredent bar-ball. The bar design connected the 3 implants, and the bar-ball design used the bar in a similar fashion but additionally incorporated distally placed ball attachments. A vertical force of 135 N was applied unilaterally to the central fossa of the right first molar. The resultant stresses that developed in the supporting structure were monitored photoelastically and recorded photographically. RESULTS For the splinted and unsplinted 3-implant-retained overdenture designs evaluated, moderate and low level stresses were observed with different attachment systems. For both the vertically oriented and inclined implants, the bar-ball attachment system produced the lowest stress level. CONCLUSIONS For vertical and inclined implant designs, lowest stress was transferred to all implants with the bar-ball attachment system, while moderate stresses were observed in implants on the loaded side with unsplinted attachment systems. The highest stress level observed with all attachment systems was moderate. For the vertical implant design, the observed stresses were distributed to all implants except with the ball attachment system, which demonstrated little discernible stresses on the non-loaded side implant.

[1]  A. Caputo,et al.  Stress transfer of four mandibular implant overdenture cantilever designs. , 2004, The Journal of prosthetic dentistry.

[2]  D van Steenberghe,et al.  Prosthetic aspects of osseointegrated fixtures supporting overdentures. A 4-year report. , 1991, The Journal of prosthetic dentistry.

[3]  A. Caputo,et al.  Effect of anchorage systems and extension base contact on load transfer with mandibular implant-retained overdentures. , 2000, The Journal of prosthetic dentistry.

[4]  R. Mericske-Stern,et al.  Overdentures: an alternative implant methodology for edentulous patients. , 1993, The International journal of prosthodontics.

[5]  Z Ben-Ur,et al.  Anterior implant-supported overdentures. , 1996, Quintessence international.

[6]  R. P. van Oort,et al.  Clinical aspects of a multicenter clinical trial of implant-retained mandibular overdentures in patients with severely resorbed mandibles. , 1996, The Journal of prosthetic dentistry.

[7]  Kiyoshi Koyano,et al.  In vitro study of a mandibular implant overdenture retained with ball, magnet, or bar attachments: comparison of load transfer and denture stability. , 2003, The International journal of prosthodontics.

[8]  U. Belser,et al.  Lack of integration of smooth titanium surfaces: a working hypothesis based on strains generated in the surrounding bone. , 1999, Clinical oral implants research.

[9]  J. Kent,et al.  Use of the integral implant for overdenture stabilization. , 1990, The International journal of oral & maxillofacial implants.

[10]  I Naert,et al.  The influence of static and dynamic loading on marginal bone reactions around osseointegrated implants: an animal experimental study. , 2001, Clinical oral implants research.

[11]  M. Piotti,et al.  3-D in vivo force measurements on mandibular implants supporting overdentures. A comparative study. , 1996, Clinical oral implants research.

[12]  G E Carlsson,et al.  Bite force and oral function in patients with osseointegrated oral implants. , 1977, Scandinavian journal of dental research.

[13]  R. Mericske-Stern.  Clinical evaluation of overdenture restorations supported by osseointegrated titanium implants: a retrospective study. , 1990, The International journal of oral & maxillofacial implants.

[14]  D. Wismeijer,et al.  Patient satisfaction with implant-supported mandibular overdentures. A comparison of three treatment strategies with ITI-dental implants. , 1997, International Journal of Oral & Maxillofacial Surgery.

[15]  R. H. Batenburg,et al.  Mandibular overdentures supported by two or four endosseous implants. A 5-year prospective study. , 2004, Clinical oral implants research.

[16]  C. Ohkubo,et al.  O-ring attachments for transitional implant-retained overdentures. , 2004, The Journal of prosthetic dentistry.

[17]  H. J. de Jongh,et al.  Forces acting on the mandible during bilateral static bite at different bite force levels. , 1980, Journal of biomechanics.

[18]  Angelo A Caputo,et al.  Influence of attachment systems on load transfer of an implant-assisted maxillary overdenture. , 2004, Journal of prosthodontics : official journal of the American College of Prosthodontists.

[19]  D van Steenberghe,et al.  Factors related to success and failure rates at 3-year follow-up in a multicenter study of overdentures supported by Brånemark implants. , 1995, The International journal of oral & maxillofacial implants.

[20]  L. Barbier,et al.  Adaptive bone remodeling around oral implants under axial and nonaxial loading conditions in the dog mandible. , 1997, The International journal of oral & maxillofacial implants.

[21]  W. Kalk,et al.  Influence of the dimensions of implant superstructure on peri-implant bone loss. , 1993, The International journal of prosthodontics.

[22]  R. Puers,et al.  Implant design and interface force transfer , 2004 .

[23]  U. Lekholm,et al.  Oral function in subjects with overdentures supported by osseointegrated implants. , 1988, Scandinavian journal of dental research.

[24]  T. Taylor,et al.  Evidence-based considerations for removable prosthodontic and dental implant occlusion: a literature review. , 2005, The Journal of prosthetic dentistry.

[25]  J. O. Rogers,et al.  The extent of maintenance required by implant-retained mandibular overdentures: a 3-year report. , 1996, The International journal of oral & maxillofacial implants.

[26]  A A Caputo,et al.  Effects of overdenture retention designs and implant orientations on load transfer characteristics. , 1996, The Journal of prosthetic dentistry.

[27]  W. Sadig.  Special technique for attachment incorporation with an implant overdenture. , 2003, The Journal of prosthetic dentistry.

[28]  R. H. Batenburg,et al.  Mandibular overdentures supported by two or four endosteal implants. A prospective, comparative study. , 1998, International journal of oral and maxillofacial surgery.

[29]  D. Hoexter.  Osseous regeneration in compromised extraction sites: a ten-year case study. , 2002, The Journal of oral implantology.

[30]  T. Haraldson,et al.  A 10-year follow-up study of the masticatory system after treatment with osseointegrated implant bridges. , 1988, Scandinavian journal of dental research.

[31]  A Vissink,et al.  Treatment concept for mandibular overdentures supported by endosseous implants: a literature review. , 1998, The International journal of oral & maxillofacial implants.

[32]  J. Brunski,et al.  Comparison of load distribution for implant overdenture attachments. , 2002, The International journal of oral & maxillofacial implants.

[33]  Angelo A Caputo,et al.  Photoelastic analysis of the effect of palatal support on various implant-supported overdenture designs. , 2004, The Journal of prosthetic dentistry.

[34]  R. Mericske-Stern,et al.  In vivo measurements of some functional aspects with mandibular fixed prostheses supported by implants. , 1996, Clinical oral implants research.

[35]  M. Richards,et al.  Photoelastic stress patterns produced by implant-retained overdentures. , 1998, The Journal of prosthetic dentistry.

[36]  M. A. van 't Hof,et al.  Denture satisfaction in a comparative study of implant-retained mandibular overdentures: a randomized clinical trial. , 1996, The International journal of oral & maxillofacial implants.

[37]  J. Lindhe,et al.  Bone reactions adjacent to titanium implants subjected to static load of different duration. A study in the dog (III). , 2001, Clinical oral implants research.

[38]  J. Deboer.  Edentulous implants: overdenture versus fixed. , 1993, The Journal of prosthetic dentistry.

[39]  H P Weber,et al.  Overdenture attachment selection and the loading of implant and denture-bearing area. Part 2: A methodical study using five types of attachment. , 2001, Clinical oral implants research.

[40]  T D Taylor,et al.  Management of the edentulous patient. , 2000, Clinical oral implants research.

[41]  T. Ichikawa,et al.  In vitro study of mandibular implant-retained overdentures: the influence of stud attachments on load transfer to the implant and soft tissue. , 1996, The International journal of prosthodontics.

[42]  H P Weber,et al.  Overdenture attachment selection and the loading of implant and denture-bearing area. Part 1: In vivo verification of stereolithographic model. , 2001, Clinical oral implants research.