In 20 patients with arch length deficiency and anterior crowding, pendulum and lingual arch appliances were inserted simultaneously in the upper and in the lower arch respectively to gain space. The patients were divided into two groups according to their dental eruption stage: ten children (six boys, four girls; mean age: 9 years, 6 months) were in the early mixed dentition, while an adolescent comparison group of the same size (three boys, seven girls; mean age: 12 years, 3 months) were in the permanent dentition at the beginning of treatment.
The main purpose of the study was to investigate whether simultaneous therapy with pendulum and lingual arch appliances is to be recommended, i.e. whether this therapy should take place as interceptive treatment in the early mixed dentition or only in the permanent dentition in adolescence. Parameters were the extent and quality of dentoalveolar effects and the side effects (mesial movement of the incisors, protrusion of the incisors, tipping of molars).
The treatment course was documented by means of study casts and lateral cephalograms. Assessment of the diagnostic records yielded the following findings: In the early treatment group the maxillary molars were distalized by the pendulum appliance by a mean distance of 4.0 +/- 1.46 mm, resulting in distal tipping by 6.1 +/- 2.18 degrees. The incisors were moved reciprocally by 1.08 +/- 1.06 mm to anterior and protruded by 7.65 +/- 4.84 degrees. In the comparison group molar distalization and molar tipping were less pronounced (2.86 +/- 1.54 mm/4.25 +/- 3.78 degrees), while mesial movement of the incisors was comparably high at 1.62 +/- 0.99 mm. At only 3.8 +/- 2.9 degrees, incisor protrusion was significantly less pronounced than in the early treatment group (p = 0.045). The proportion of molar distalization in the total movement was higher in patients in the early mixed dentition: 79.83 +/- 15.38% vs 60.71 +/- 26.64%. During the early therapy with the lingual arch appliance in the lower arch, the molars were uprighted to the distal by 2.4 +/- 0.97 degrees and the incisors were tipped to labial by 5.0 +/- 1.83 degrees. In the adolescent control group, molar uprighting was less pronounced and the degree of incisor protrusion was significantly lower (2.75 +/- 1.11 degrees, p = 0.004).
With the appropriate indication, the combined therapy with the two compliance-independent appliances described can be recommended for gaining sagittal arch length in the early mixed dentition.