Nonsurgical treatment of an adult patient with severe transversal skeletal discrepancy: Tooth bone-borne tandem expander and hybrid aligner approach.

BACKGROUND: Although they have proven effective in the resolution of mild to moderate malocclusions, aligners demonstrate substantial limitations. More complex malocclusions therefore require a combination of auxiliaries, or a hybrid approach involving both aligners and fixed appliances, such as miniscrew-supported appliances or sectionals. This case report presents a 25-year-old female patient with a severe transversal discrepancy associated with an anterior open-bite tendency effectively treated with a tooth bone-borne palatal expander characterized by two expansion screws (tandem expander) and a hybrid treatment with aligners. METHODS: After accurate matching between the pretreatment cone-beam computed tomography scan and digital models, four self-drilling miniscrews were inserted palatally using a computer- aided design and computer-aided manufacturing surgical template to guide their correct and safe placement, and a tooth bone-borne appliance was fitted. After this first phase, the hybrid clear aligner approach was used to obtain alignment, leveling, and arch coordination, with the use of a partial lingual fixed appliance. RESULTS: Transverse maxillary deficiency was corrected, crowding has been resolved, Class I molar and canine relationship were obtained, and marginal ridges has been aligned. CONCLUSIONS: Double jackscrew of the tandem expander enabled effective expansion of both the posterior segments as required to correct the skeletal discrepancy and the anterior region, thus relieving the dental crowding. Lingual sectional appliances have been shown to increase the effectiveness of clear aligners which, on the other hand, have been shown to be effective in closing the anterior bite by retroclination of the maxillary and mandibular incisors and, only minimally, by extrusion movements.

Is a non-radiological-assisted method valid for establishing crown-root relationships in an orthodontic set-up incorporating the roots? A retrospective study.

INTRODUCTION: This study aimed to obtain information on the relationship between crown and root in terms of morphology - dimensions and crown-root angles -to be used for orthodontic set-ups without the use of radiological examinations. MATERIAL AND METHODS: All the good quality CBCTs of patients obeying the eligibility criteria, from 2000 to 2015, were analysed. All teeth were analysed except for third molars. Six variables were evaluated: crown (CL) and root length (RL), crown width (CW), root width (RW), crown-root angles in both the frontal (CR-frontal) and sagittal plane (CR-sagittal). All teeth were divided into 3 groups according to number of root (single, two, three-rooted). The measurements were assessed with the Invivo professional software and then, subjected to correlation matrices and linear regression statistical analysis in order to find any significant correlations between crown and root measurements (α≤0.05). RESULTS: Seventy-three out of 247 good quality CBCTs were assessed. Correlation matrices statistical analysis showed linear correlations for some variables investigated, especially for CW/RW pairing in all subgroups (r=0.81, r=0.70 and r=0.58 respectively for single-, two- and three-rooted) and CL/RL in the single-rooted subgroup (r=0.29). Subsequent linear regression analysis allowed to obtain information about roots starting from crown measurements by means of equations [RW=0.76+(0.73×CW) and RL=10.94+(0.25×CL) for single-rooted teeth; RL=1.11+(0.73×CW) and RW=0.99+(0.76×CW), respectively for single- and two-rooted teeth]. No linear correlation was found between crown measurements and C-R angular values. CONCLUSION: It is possible to obtain root information starting from some crown measurements but these do not fulfil the need of minimal information to guarantee a perfect root position starting from that of crown.

Variations in Function and Vocal Acoustic Characteristics After Orthognathic Surgery: Preliminary Results

ABSTRACT Objective: To determine the effects of orthognathic surgery on oral function and vocal quality in order to assess the need for speech therapy after surgery. Material and Methods: Thirty-seven patients scheduled for mono-jaw surgery, specifically maxillary (G1:15 patients), mandibular advancement (G2:10 patients) or mandibular set-back (G3:12 patients), were recruited for this prospective cohort study. Evaluation of oral functions, video recordings of speech articulation and audio recordings of voice were obtained before surgery (T0), and at 1 (T1) and 6 months (T2) after surgery. Spectrographic analysis and self-evaluation questionnaire regarding the vocal performance (VAPP) were performed. Both qualitative and quantitative statistical analysis was performed, mainly using generalized linear models for dichotomous data (p<0.05). Results: The formant frequencies (F1 and F2) of the main vowels vary after orthognathic surgery according to the type of surgery. Before surgery, 84% of patients analyzed showed difficulties in breathing and positioning the tongue both at rest and swallowing. Thanks to surgical correction of the malocclusion, the major part of these issues were resolved within 6 months. In 25% of cases, a change in the voice and/or articulation had occurred. Conclusion: Vocality improves after orthognathic surgery and it changes in relation to the type of surgery. However, vocality did not normalize completely. Speech assessment should be considered after surgery in order to offer adequate speech therapy if necessary.