Changes in Measurements of Segner-Hasund Analysis in Patients with Mandibular Prognathism after Orthognathic Surgery

Abstract

In mandibular prognathism abnormal proportions of the facial part of the cranium are reflected in impaired facial aesthetics. Moreover, it is associated with abnormalities concerning the alveolar ridge of the mandible and the maxilla, as well as different types of malocclusion. Functional disorders, such as speech abnormalities, temporo-mandibular joint dysfunction and difficulty in biting and chewing food are also common [1][2][3]. AbstractBackground. In mandibular prognathism abnormal proportions of the facial part of the cranium are reflected in impaired facial aesthetics. Surgical methods that are currently used in Poland in order to correct mandibular prognathism include bilateral sagittal split ramus osteotomy (BSSO) and extraoral vertical ramus osteotomy (EVRO). There are also different kinds of cephalometric parameters measured on cephalograms used to plan and evaluate the outcomes of surgical and orthodontic treatment concerning mandibular prognathism. Objectives. The aim of this research was to assess the early treatment outcome observed after vertical and sagittal osteotomy of the mandibular ramus with the use of cephalometric Hasund-Segner analysis. Material and Methods. Overall, 98 lateral cephalograms, made before surgery and at least 6 months after the surgery, were collected in order to perform the analysis of treatment results. Cephalometric analysis proposed by Hasund and Segner was used to assess bone and soft tissue changes after orthognathic surgeries. Results. Six months after the orthognathic treatment we observed a relevant improvement in parameters describing the sagittal relationship between the maxilla and the mandible, and between the mandible and the skull base. Positive influence was also noticed in the case of vertical relationship parameters of the Hasund-Segner analysis. Conclusions. Both methods used in surgical treatment of mandibular prognathism, namely the external vertical ramus osteotomy and the bilateral sagittal split osteotomy, had a positive influence on the anterior-posterior relation of the mandible towards the skull base and the maxilla assessed in Hasund-Segner cephalometric analysis. There are small differences related with the impact that the surgery has on hard and soft tissue profile, depending on the surgical technique. BSSO had greater impact on Holdaway's angle than EVRO (Dent. Med. Probl. 2016, 53, 1, 13-21).