MSC - Page 27

TREATMENT EFFECTS OF R-APPLIANCE IN VERTICAL GROWING PATIENTS-CASE SERIES Figure 1. The R-appliance 1. ANB > 4°, SNB < 78°, overjet > 4 mm at the initial lateral cephalograms; 2. Nonsyndromic or medically compromised patients; 3. No previous surgical intervention; 4. No use of other appliances before or during the period of functional treatment. 5. No skeletal asymmetry 6. Vertical growth pattern (GoGn-SN > 32°) All the patients were treated with the R-appliance (10, 12, 13) (Figures 1 and 2). The patients were instructed to wear the appliances full-time except for eating, contact sports and tooth brushing. The R-appliance is a tooth and tissue borne appliance. It consists of buccal and lingual shields, which are connected to each other through the occlusal clearance during bite construction. These shields are extended to the distal of the first permanent molars and cover the buccal and lingual regions and the depth of the vestibule. The lingual shield should be fabricated with minimal undercut relieve. The left and right lower lingual shields are connected and reinforced with a heavy archwire (1mm diameter) to withstand the load of muscular activity. A heavy wire (1mm diameter), which acts as a tongue bow, is positioned posterior to connect the right and left acrylic parts on the palatal aspect in order to reinforce the appliance. The labial bow is constructed of 0.7 mm stainless steel wire extended from canine to canine with vertical loops in the canine region. In this group, the construction bites were taken with the upper and lower anterior teeth in an edge to edge occlusion with more than 4 mm of posterior clearance. In other words, the thickness of the connection between buccal and lingual shields would be more than 4 mm. Lateral cephalograms of the patients were taken in centric occlusion at the start (T1) and completion (T2) of functional treatment. SNA, SNB, ANB, Y-axis (angle between the line connecting Sella to Gnathion and SN), GoGn-SN (angle between SN and mandibular plane), Gonial angle (the angle formed by the junction of the posterior and lower borders of the lower jaw), Inclination STOMA.EDUJ (2014) 1 (2) Figure 2. The R-appliance in the mouth angle (angle between perpendicular line dropped from  N-Se at  N’ and palatal plane), 1 to SN (angle between long axis upper central incisor and anterior cranial base), IMPA (angle between the long axis of the lower central incisor and mandibular plane), interincisal angle (angle between upper and lower incisors), 1 to NA (distance between maxillary central incisor to N-A), ī to NB (distance between mandibular central incisor to N-B), occlusal to SN (angle between SN and occlusal plane), and Jarabak index (the ratio between posterior and anterior face heights; S–Go/N–Me) were measured on pre and post treatment radiographs. Two weeks after the first measurements, the tracings and measurements were repeated by one blinded dentist on 10 random cephalograms at the beginning and end of the treatment. To assess the reliability of the measurement, the intraclass correlation coefficients were calculated for each variable in the T1 and T2 cephalograms. No significant differences were found between the first and second measurements of those randomly selected cephalograms. Data were tested for normality and appropriate statistical test were applied. Statistical significance was set at P<0.05. The magnification factor of the cephalograms was standardized at 8 per cent. The Statistical Package for Social Sciences, Version 20 (SPSS Inc. Chicago, Illinois, USA) was used to analyze the data. Paired T-test was used for evaluation of pre and post treatment measurements if the distribution was normal; otherwise, Wilcoxon test was used. Results: After 16 (SD 0.4) months of treatment paired T-tests showed significant ANB decrease of 3.2° (SD 1.6°) (P<0.001) and SNB increase of 3.3° (SD 1.5°) (P<0.001). IMPA significantly decreased from 101° (SD 7.2°) to 98° (SD 9.7°) (P<0.02). 1 to SN also significantly decreased for 6.1° (SD 5.6°). Jarabak index increased from 59.2% (SD 3.4%) to 61% (SD 3.5%) (P<0.007). Before and after treatment changes can be seen in table 1. 103