Edition V16N05 | Year 2011 | Editorial Article | Pages 119 to 126
Introduction: Cleft lip and palate patients usually have severe maxillary deficiencies, particularly in the anterior region of this arch and their treatment should include maxillary expansion.> Objective: To evaluate the expansion pattern of three brands of fan-type expander screws to correct transverse deficiencies. Methods: Eighteen expansions on typodonts were performed with 6 simulations for each group: G1 – Dentaurum® screw; G2 ? Leone® screw; and G3 ? Morelli® screw. For each trial 13 activations of 2/4 of a turn each were made with a 5.2 mm screw opening. Measurements were made at baseline (T1), after half of the activations (T2) and at the end of the trial (T3). A caliper was used to make the following measurements: Inter-first premolars (IP1), inter-second premolars (IP2) and intermolar (IM) widths and arch length (AL). The Kolmogorov- Smirnov, Tukey, Friedman and ANOVA tests were used to analyze data. Results: All groups had a ?V? shaped opening pattern and the greater expansion was found in the anterior region of the arch, which was more evident in the G3 (29.58% in IP1 and 9.73% in IM). The increase in AL was similar in G1 and G3 (+12.65% and +12.13%) and the lowest value was found in G2 (+8.23%). Conclusions: All the fan-type expander screws used in this study may be used to treat dental arch transverse deficiencies. However, the use of the Morelli screw resulted in a greater opening in the anterior region than in the posterior region, an important characteristic in the treatment of cleft lip and palate patients. Further clinical studies should be conducted to confirm these findings.