Safe zones of the maxillary alveolar bone in Down syndrome for orthodontic miniscrew placement assessed with cone-beam computed tomography

A novel biomechanical system to intrude the upper incisors and control overbite: Posterior miniscrew-assisted lever arm and 2 cases report

RATIONALE

Overbite control is a key factor in orthodontic treatment. In some cases, incisor intrusion is essential and could be an optimal strategy for overbite control. The aim of this article was to introduce a biomechanical system called the posterior miniscrew-assisted lever arm, which is innovative in using existing posterior miniscrews to intrude the upper incisors and to control anterior overbite while simultaneously retracting the anterior teeth. Its efficiency in incisor intrusion has been proved with 2 cases.

PATIENT CONCERNS

Two adult women who came for orthodontic treatment with the chief complaint of convex profile were included in this study.

DIAGNOSIS

Both patients had similar malocclusions of Class II molar relationship, anterior deep overjet, and anterior deep overbite.

INTERVENTIONS

Their treatment plans were to extract 4 first premolars and insert 2 maxillary posterior buccal miniscrews. After teeth aligning and leveling, en masse retraction was started in both arches. During the space-closing stage, posterior miniscrew-assisted lever arms were placed in their upper arches so as to intrude upper incisors and control the overbite.

OUTCOMES

After respectively 4 months and 3 months of incisor intrusion, the anterior overbite was successfully reduced to the normal range in each patient. Cephalometric analysis and superimposition also confirmed the treatment effect of this biomechanical system on incisor intrusion.

LESSONS

The posterior miniscrew-assisted lever arm is a valuable biomechanical system for intruding incisors and controlling anterior overbite.

Evaluation of the craniofacial and oral characteristics of individuals with Down syndrome: A review of the literature

The aim of this investigation was to describe the craniofacial and oral characteristics of children and/or adolescents with and without Down syndrome (DS). A bibliographic search of the Medline database (via PubMed), Scopus and SCIELO was performed using the keywords "craniofacial characteristics", "dental characteristics" and "Down syndrome". Systematic reviews, observational cross-sectional and longitudinal studies were included. On the contrary, case reports, letters to the editor, editorials and opinion articles were excluded. 251 articles were recovered, and only 30 fulfilled the selection criteria. DS patients were characterized by reduced dimensions of the maxillary bone, mandible, and skull base, compared to normal patients. Likewise, some of these abnormalities influenced more frequent presentation of a class III malocclusion in these patients. On the other hand, this population group showed a higher prevalence of periodontal diseases, less risk of dental caries, and the presence of alterations in the tongue, lips, dental development and palate morphology. The quality of life of these individuals is affected by difficulties in swallowing, talking, eating or breathing through the nose. In conclusion, the craniofacial and oral characteristics of DS patients present various alterations compared to healthy patients, and these alterations have a negative impact on their quality of life.