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This study investigated, using cone beam computed tomography (CBCT), the spatial mandibular positioning after rapid maxillary expansion (RME) in Class II Division 1 malocclusion. This prospective study evaluated 17 children (mean initial age 10.36 years old) presenting Class II, Division 1 malocclusion and skeletal maxillary constriction that underwent to RME Haas' protocol. CBCT was performed before treatment (T1), immediately after the stabilization of expander screw (T2) and after the retention period of 6 months (T3). The scans were managed in Dolphin Imaging ® 11.0 software, where landmarks (right and left condylion, right and left gonion, and menton) were positioned and measured in relation to sagittal, coronal and axial plane to verify, respectively, transverse, anteroposterior and vertical displacement of the mandible. Paired Student's t-test was used to identify significant differences (p<0.05) between T1 and T2, T2 and T3, and T1 and T3. After RME, right and left gonion moved downward (1.11 mm and 0.89 mm) and menton displaced downward (1.90 mm) and backward (1.50 mm). During the retention period, only anteroposterior displacement was significant, with the right and left gonion (0.97 mm and 1.26 mm) and the menton (2.29 mm) moving forward. Three-dimensional assessment of the mandible in Class II Division 1 patients subjected to RME showed a transitory backward and downward mandibular positioning, without any lateral displacement. The 6-month retention period allowed the mandible shifting significantly forward, exhibiting a more anterior position compared with the initial condition, even remaining in a more downward direction.

Peri-implant inflammation contributes for loss of secondary stability of orthodontic mini-implants. The investigation of microbial colonization in this area would benefit its control, and consequently favor the long-term success of mini-implants. Therefore, the aim of this study was to determine the establishment and the evolution of microbial colonization process in orthodontic mini-implants for 3 months, since the time of their installation. One-hundred and fifty samples collected from 15 mini-implants were investigated from baseline up to 3 months. The biological material was obtained from peri-implant area using paper points. Nonspecific, Streptococcus spp, Lactobacillus casei and Candida spp colonizations were analyzed by cell growth methods. Porphyromonas gingivalis colonization was observed by 16S rDNA-directed polymerase chain reaction. Data from cell growth were submitted to the Wilcoxon sign rank test and results from molecular analysis were presented in a descriptive way. There was no significant difference in the microbial colonization among the examined time intervals, except for Streptococcus spp, between baseline and 24 h, which characterized the initial colonization in this time interval. Lactobacillus casei and Candida spp colonizations were insignificant. No Porphyromonas gingivalis was detected among the analyzed samples. The microbial colonization of mini-implants did not significantly change during the study. However, it should be monitored by orthodontists, since it is an important factor for mini-implants success.

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Introduction: Etiology of dental crowding may be related to arch constriction in diverse dimensions, and an appropriate manipulation of arch perimeter by intervening in basal bone discrepancies cases, may be a key for crowding relief, especially when incisors movement is limited due to underlying pathology, periodontal issues or restrictions related to soft tissue profile. Objectives: This case report illustrates a 24-year old woman, with maxillary transverse deficiency, upper and lower arches crowding, Class II, division 1, subdivision right relationship, previous upper incisors traumatic episode and straight profile. A non-surgical and non-extraction treatment approach was feasible due to the miniscrew-assisted rapid palatal expansion technique (MARPE). Methods: The MARPE appliance consisted of a conventional Hyrax expander supported by four orthodontic miniscrews. A slow expansion protocol was adopted, with an overall of 40 days of activation and a 3-month retention period. Intrusive traction miniscrew-anchored mechanics were used for correcting the Class II subdivision relationship, managing lower arch perimeter and midline deviation before including the upper central incisors. Results: Post-treatment records show an intermolar width increase of 5 mm, bilateral Class I molar and canine relationships, upper and lower crowding resolution, coincident dental midlines and proper intercuspation. Conclusions: The MARPE is an effective treatment approach for managing arch-perimeter deficiencies related to maxillary transverse discrepancies in adult patients.