60 single-rooted teeth were instrumented with R40 reciprocal files (VDW). Before obturation, the roots were surrounded by splitted Biresin blocks. The specimens were randomly assigned to four groups according to the used obturation technique and obturated with AH Plus and following techniques: (1) single cone technique, (2) lateral compaction, (3) Thermafil, (4) warm vertical compaction. After storage the roots were retreated as well with reciproc files R40. Following, the apical, middle and coronal root portion were microphotographed by a light microscope (Leica). The residual root filling material was evaluated separated from sealer- and gutta-percha-leftovers and calculated in terms of area. Additionally, the retreatment time was investigated. The statistical analysis was performed with SSPS Win 19.0. The analysis of the data illustrates that there are significant distinctions in every three root canal sections between the single groups. This is reflected both in the residual sealer and in the gutta-percha value. Warm obturation techniques showed a higher ammount of residual gutta-percha, whereas cold obturation techniques leave us with more residual sealer material. The differences between the groups 1 / 2 as well as 3 / 4 were not significant. Calculating the whole root canal filling material there are no significant differences among the several groups. The retreatment time also prove significant differences among the groups. Conclusions: Reciprocal instruments enable the safe retreatment of root canal fillings. Additional measures like a higher treatment size or the application of a solvent may be necessary to increase the retreatment efficacy.