Investigation of the effects of subapical horizontal incisions on the intrusion of maxi̇llary posterior teeth by using zygomatic anchorage

The aim of this study was to investigate the effects of subapical horizontal incisions and changes in dentofacial structures during intrusion of maxillary posterior teeth with zygomatic anchorage by examining with lateral cephalometric films. A total of 24 female and 5 male patients aged 13-23 years in permanent dentition, having anterior open bite were admitted to this randomized and prospective study. Two groups were introduced as follow: zygomatic anchorage assisted intrusion with subapical osteotomy (ZAAI+KO) and zygomatic anchorage supported intrusion (ZAAI) group (n=12). The mean duration of treatment was 4.75 months in the ZAAI+KO group and 4.33 months in the ZAAI group. A total of 48 lateral cephalometric films taken at the beginning and end of the treatment. For diagnostic purposes, intraoral and extraoral orthodontic photographs, lower and upper plaster diagnostic models and panoramic films of each patient before and after treatment were examined. The mean chronological age of ZAAI+KO group was 17.03, and of ZAAI group was 16.46 years. Mean FH┴N–A value of ZAAI group after treatment was higher than that of ZAAI+KO group (p<0.05). During treatment, of the cranial measurements, there was a significant increase in S–N distance in both groups, while SArGo angle of ZAAI+KO group significantly decreased. Among maxillary skeletal measurements, SN/ANSPNS angle of ZAAI+KO group significantly decreased while Co–A distance of ZAAI group increased (p=0.025). Among mandibular skeletal measurements, significant increases were observed in SNB and FH┴N–Pg while significant decreases in SN/SGn, SN/ GoGn and ArGoMe angles of ZAAI+KO group. In ZAAI group, significant increases in SNB, FH┴N–Pg and Co–Pg measurements, and significant decreases in SN / SGn and SN / GoGn angles were detected. Among maxillo- mandibular measurements, significant decreases were observed in ANB and ANSPNS / GoMe of both groups. Among face height measurements, N–Me and ANS–Me distances significantly decreased in both groups. Among maxillary dentoalveolar measurements, U6–MaxD distance decreased in both groups; an increase was observed in U1–MaxD of ZAAI group. Among mandibular dentoalveolar measurements L6–MandD of both groups significantly decreased. Among interdental measurements, overbite value significantly increased in both groups and overjet distance decreased in ZAAI group. Among soft tissue measurements, N'SnPg' angle significantly decreased in ZAAI group. The corticotomy procedure in patients with zygomatic mini-plate placed to anchor the intrusion of the maxillary posterior teeth may provide the protection of the soft tissue as well as resulting in the maxillary and mandibular skeletal and dentoalveolar effects.