Investing the effects of preorthodontic trainer appliance on deep bite patients in early mixed dentition period

Deep bite is a complex orthodontic problem involved in a teeth or whole dentition, alveoler bone, mandible and maxilla and /or soft tissues. The goal of early orthodontic treatment is to achieve dental and skeletal harmony prior to the complete eruption of the permanent dentition. The aim of the present study was to evaluate the dental and skeletal effects of a myfunctional appliance: the preorthodontic trainer in patients with deep bite in the age group 8-10 years and comparison with the normative growth data of children in the same aged group. 18 patients (10 girls, 8 boys) showed 4 mm or more overbite, mandibular retrusion and hypodiverjant growth pattern were included in the treatment group with preorthodontic trainer. 18 patients (11 girls, 7 boys) showed the same malocclusion and had no orthodontic treatment history included in the control group. The mean age in the treatment group was 8 years 4 months and in the control group 8 years 7 months. The patients were instructed to use the trainer every day for one hour and overnight while they sleep. The extraoral and intraoral photographs, lateral cephalograms and cast models of both groups were taken before (T0) and after (T1) the treatment / observation period. Final photographs, lateral cephalograms and cast models (T1) were obtained 13,7±1,8 months after trainer application, compared with a mean of 12,4±1,4 months later for the control group. Significant reduction in the overbite (-0,99mm, p˂0,001) were noted in the treatment group when compared with the control group at the end of the study period. Significant increase in SNB angle (1,17º , p ˂ 0,001) and decrease in ANB angle (-0,9º, p ˂ 0,001) was observed. SNGoGn, FH-MD, PD-MD ve OD-SN values showed a significant increase in the treatment group. Lower anterior facial height (ANS-Me) increased significantly in the treatment group ( p ˂ 0,001). The mandibular growth in the treated group when compared with the control group were insignificant. Differences of other skeletal parameters between treatment and control group were insignificant. Increase of the proclination of maxillary (p = 0,006) and mandibular incisors (p ˂ 0,001) were noted significantly different in the treatment group when compared with the control group. A significant reduction of interincisal angle was observed (p ˂ 0,001). The difference in intermolar width of maxillary and mandibular arch was insignificant and involded in normal growth period. There was a significant increase in the maxillary primary intercanine width (1,04 mm, p = 0,001) and in the mandibular primary intercanine width (1,11 mm, p = 0,019) in the treatment group compared with the control group. At the end of the study period, preorthodontic trainer group subjects showed anterior rotation and sagittal growth of mandible, provided inclination of incisors and passive arch expansion. The preorthodontic trainer appliance produced more dentoalveolar changes and limited skeletal effects. According to the findings of the present study, it may be suggested that preorthodontic trainer appliance is effective on correction of Class II relationship and overbite on deep bite patients in mixed dentition period and improves the patient's facial profile. Key Words: deep bite, early orthodontic treatment, myofunctional therapy, preorthodontic trainer appliance