Aim. The relationship between the cutting efficiency of NiTi rotary files and the outcome of their clinical application has not been clearly identified yet. Mtwo files (Sweden&Martina) have been available on the market since several years and are known for their cutting ability. As well as Mtwo, the instruments of the Alphakite system (Komet) are used in a full-length technique but they are characterized by negative rake angles. Because of the more recent introduction of Alphakite files, their performance has been tested by fewer studies. The aim of the present clinical trial is to assess the outcome of the endodontic treatment of teeth affected by periapical periodontitis using Mtwo or Alphakite rotary files.
Materials and methods. Patients (mean age 42.5±14.4 years) presenting a tooth with periapical pathosis that had not been previously treated were included in the experimentation and randomly assigned to two treatment groups: G1 (n=55), Mtwo and G2 (n=39), Alphakite. The instruments were used according to the instructions of the manufacturer. The irrigation protocol was the same for both groups and consisted of rinses with 5.25% sodium hypochlorite (2,5 ml after each instrument). In both groups, canals were filled with the continuous wave of condensation technique. Clinical examination (pain assessment, sensitivity to percussion) and a periapical radiograph were performed at baseline and after six months. Periapical healing was scored according to the scale described by Katebzadeh et al. (2000): 1=healed, 2=improved, 3=failed (increase or no change in the lesion size), 4=unreadable radiograph. Clinical data and radiographic scores were analyzed statistically by non-parametric methods making use of dedicated software (p<0.05).
Results. The statistical analysis revealed that the baseline characteristics of the two experimental groups (age, type of tooth, number of canals per tooth, sensitivity to percussion and pain) were similar and thus comparable. Complete radiographic healing occurred in 54.5% of recalled patients in G1 and in 51.3% in G2. In the other cases the periapical lesion was found to be diminished in size but still present, with the exception of two patients in G1 with score 3. The symptoms almost disappeared in both groups, with only one patient of G1 still reporting pain at the six-month recall. No statistical significant difference between the tested file systems emerged. The type of tooth was not a determining factor for both clinical and radiographic healing.
Conclusions. Under the conditions of the present study, the two tested systems were similarly effective for the treatment of periapical lesions. After only six months, relatively high success rate was obtained; the follow-up of ongoing healing processes must be extended to exclude the possibility of late failure. The issue regarding the influence of the cross section design of endodontic rotary files on the clinical outcome remains unsolved and deserves further investigation.
