The Randomized Shortened Dental Arch Study: Tooth Loss Over 10 Years

Michael H. Walter, Univ-Prof Dr Med Dent/Jens Dreyhaupt, Dr Rer Nat/Wolfgang Hannak, Dr Med Dent/Stefan Wolfart, Univ-Prof Dr Med Dent/Ralph G. Luthardt, Univ-Prof Dr Med Dent/Helmut Stark, Univ-Prof Dr Med Dent/Peter Pospiech, Univ-Prof Dr Med Dent/Torsten Mundt, PD Dr Med Dent Habil/Matthias Kern, Univ-Prof Dr Med Dent/Klaus Walter Böning, Prof Dr Med Dent/Bernd Wöstmann, Univ-Prof Dr Med Dent/Herbert Scheller, Univ-Prof Dr Med Dent/Florentine Jahn, PD Dr Med Dent Habil/Wilfried Reinhardt, PD Dr Med Dent Habil/Joerg Strub, Univ-Prof Dr Med Dent/Birgit Marré, Dr Med/Guido Heydecke, Univ-Prof Dr Med Dent: Purpose: This study aimed to compare the long-term outcomes of two different nonimplant treatments in the bilateral shortened dental arch (SDA). Materials and Methods: In a multicenter randomized controlled clinical trial, patients with complete molar loss in one arch were assigned to one of two different nonimplant treatments. In the partial removable dental prosthesis (PRDP) group, patients were provided with a distal-extension prosthesis retained with precision attachments. In the SDA group, patients were treated according to the SDA concept by preserving or restoring a premolar occlusion. Results: Of the 152 treated patients, 82 reached the 10-year examination independent of their dental or prosthetic status. In the intention-to-treat analysis, the survival rates for tooth loss at 10 years were 0.44 (95% confidence interval [CI]: 0.30 to 0.56) in the PRDP group and 0.52 (95% CI: 0.37 to 0.65) in the SDA group. For tooth loss in the study arch, the survival rates were 0.67 (95% CI: 0.52 to 0.78) in the PRDP group and 0.60 (95% CI: 0.45 to 0.73) in the SDA group. The number of teeth lost was higher than expected. In a multivariate analysis using a multiple Cox regression model, the covariates age (unit: 1 year, Hazard Ratio [HR]: 1.033, P = .03) and DMFT value (unit: 1 tooth, HR: 1.121, P = .03) were significant for time to first tooth loss in the study arch. Conclusion: The results suggest an overestimation of the influence of the prosthetic management of the bilateral SDA. In treatment decisions, patient preferences should be considered with appropriate weight.