Facial and Dentoalveolar Changes Following Orthodontic Treatment of Bimaxillary Protrusion in Two Sisters
Year: 2026
Type: article
Study design: Case Report
Abstract: Bimaxillary dentoalveolar protrusion is characterized by excessive labial inclination and protrusion of the maxillary and mandibular incisors and is frequently associated with lip protrusion, lip incompetence, and increased facial profile convexity. Orthodontic treatment, particularly when combined with premolar extractions, aims to retract and reposition the anterior dentoalveolar segments, thereby improving dentofacial relationships and the soft-tissue profile. The soft-tissue response to dentoalveolar changes, however, may vary according to individual anatomical characteristics, growth status, and the timing of orthodontic intervention. We report the cases of two sisters presenting with bimaxillary dentoalveolar protrusion and broadly similar pretreatment dentofacial characteristics. These similarities included a comparable skeletal pattern, maxillary and mandibular incisor protrusion, and proclination, as well as similar soft-tissue features characterized by lip protrusion, lip incompetence, and increased facial profile convexity. Despite these similarities, the two patients differed substantially in age and growth status, providing an opportunity to descriptively compare their dentoalveolar and soft-tissue responses to orthodontic treatment performed at different stages of dentofacial development. The younger sister, aged 12 years, was still undergoing craniofacial growth and was treated during the transition to permanent dentition. At the initial examination, some primary teeth were still present. These teeth were allowed to exfoliate physiologically, after which the first permanent premolars were extracted as part of the orthodontic treatment plan. The older sister, aged 23 years, presented with a fully established permanent dentition and completed craniofacial growth and was treated with extraction of the second premolars. Both patients were treated by the same orthodontist. Changes in incisor position and the perioral soft-tissue profile were assessed clinically and cephalometrically before and after orthodontic treatment, with long-term follow-up. In both patients, treatment resulted in retraction and uprighting of the incisors, accompanied by improvement in the soft-tissue profile and lip relationship. In Case 1, mandibular incisor uprighting was confirmed by a decrease in the incisor mandibular plane angle from 104.3° before treatment to 100.9° after treatment. Improved lip competence and reduced visible mentalis muscle activity during lip closure were also observed clinically. These soft-tissue findings were based on clinical examination and photographic assessment and were not evaluated using a standardized quantitative protocol. The comparison of these two cases suggests that the timing of orthodontic intervention and the patient's growth status may be associated with differences in the dentoalveolar and soft-tissue response to the treatment of bimaxillary dentoalveolar protrusion. Nevertheless, these findings are exploratory and should be interpreted cautiously. Given the descriptive nature of this two-case comparison and the differences in treatment protocol, particularly the premolars selected for extraction, no causal relationship between growth status, treatment timing, and treatment response can be established.
Source: Cureus
Institution: Université Mohammed VI des Sciences et de la Santé
Language: English
Subfield: Orthodontics
Field: Dentistry
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W7214919409