Objective: To identify the appropriate power level for electric welding of three commercial brands of nickel-titanium (NiTi) wires. Methods: Ninety pairs of 0.018-in and 0.017 × 0.025-in NiTi wires were divided into three groups according to their manufacturers - GI (Orthometric, Marília, Brazil), GII (3M OralCare, St. Paul, CA) and GIII (GAC,York, PA) - and welded by electrical resistance. Each group was divided into subgroups of 5 pairs of wires, in which welding was done with different power levels. In GI and GII, power levels of 2.5, 3, 3.5, 4, 4.5 and 5 were used, while in GIII 2.5, 3, 3.5 and 4 were used (each unit of power of the welding machine representing 500W). The pairs of welded wires underwent a tensile strength test on an universal testing machine until rupture and the maximum forces were recorded. Analysis of variance (ANOVA) and post-hoc tests were conducted to determine which subgroup within each brand group had the greatest resistance to rupture. Results: The 2.5 power exhibited the lowest resistance to rupture in all groups (43.75N for GI, 28.41N for GII and 47.57N for GIII) while the 4.0 power provided the highest resistance in GI and GII (97.90N and 99.61N, respectively), while in GIII (79.28N) the highest resistance was achieved with a 3.5 power welding. Conclusions: The most appropriate power for welding varied for each brand, being 4.0 for Orthometric and 3M, and 3.5 for GAC NiTi wires.

This original case report describes the morphologic changes caused by a mandibular condylar osteochondroma (OC) on a female patient and its treatment. The changes were identified by comparing her final records from a previous orthodontic treatment, without the presence of OC, to records taken before a second treatment, with a developed OC. The diagnostics and treatment for the OC and its consequences were described and discussed in this paper. Treatment included orthodontics with a lingual appliance, low condylectomy on the affected side, high condylectomy on the contralateral side, bilateral disc repositioning and orthognathic surgery. It was concluded that the OC caused a Class III subdivision malocclusion, midline deviation and an edge-to-edge bite on the left side, a cant of the occlusal plane on the Z-axis and a deviation of the pogonion to the left. Treatment was successful and stable long term (36 months) with good occlusal, aesthetical and functional results.