Resumen de Support Ratio Between Abutment and Soft Tissue Under Overdentures:: A Comparison Between Use of Two and Four Abutments

Manami Abe, Masahiro Wada, Takanori Ando, Yoshinobu Maeda, Tsung-Chieh Yang

• Purpose: The purpose of this preliminary in vivo study was to compare force distribution on abutments (tooth or implant) and tissues supporting overdentures with two or four abutments.

  Materials and Methods: A convenience sample of five subjects with tooth and/or implantsupported overdentures was enrolled. Recordings were completed on each subject using a forcemeasuring system mounted on a metal framework with four anteroposterior spread abutments (A), four abutments with denture bases (B), and on two anterior abutments with denture bases (C). The tissue-support ratio (TSR) was calculated as (A−B)/A or (A−C)/A.

  Results: TSR values changed 1.5 to 2 times when the number of abutments was reduced from four to two.

  Conclusion: The amount of tissue strain on the posterior residual ridge increased when the number of abutments was reduced.