Sérgio Estelita Barros

Effect of mini-implant diameter on fracture risk and self-drilling efficacy.

INTRODUCTION The aim of this study was to evaluate the effect of mini-implant diameter on fracture risk and self-drilling efficacy. METHODS A sample of 405 mini-implants with 9 diameters from 1.2 to 2.0 mm was used. Ten mini-implants of each diameter were placed in artificial bone, and 25 were placed in pig iliac bone to evaluate placement torque (PT) and axial placement load (APL), which represents self-drilling efficacy. Ten mini-implants of each diameter were used to determine fracture torque (FT). The different diameters were compared regarding PT, FT, and APL. The fracture risk of each diameter was evaluated by the fracture resistance index (FT/PT × [FT-PT]). The PT and APL changes during placement were correlated. RESULTS Only PT and FT were different for all mini-implant diameter changes. PT and FT showed a strong correlation with the mini-implant diameter, but the APL was weakly to moderately correlated. The fracture resistance index was remarkably greater for each 0.1 mm added in diameter. The PT increased significantly, whereas the APL was progressively reduced during placement. CONCLUSIONS Increases in mini-implant diameters significantly influenced the increases of PT and FT on quantities that progressively reduced the fracture risk. The self-drilling efficacy was not strongly influenced by diameter.

Long-term stability of surgical-orthodontic open-bite correction

INTRODUCTION The objective of this study was to evaluate the long-term stability of open-bite surgical-orthodontic correction. METHODS Thirty-nine patients at an initial mean age of 20.83 years were evaluated cephalometrically at pretreatment (T1), immediately after treatment (T2), and at the last recall (T3), with a mean follow-up time of 8.22 years. The surgical protocol included single-jaw or double-jaw surgery. Because the patients had different anteroposterior malocclusions, the sample was divided into a Class I and Class II (I-II) subgroup (3 Class I, 20 Class II malocclusion patients) and a Class III subgroup (16 patients). The dentoskeletal characteristics of the total sample and the subgroups were compared at T1, T2, and T3 with dependent analysis of variance (ANOVA). RESULTS Overbite relapse in the posttreatment period was statistically significant in the whole sample and the Class I-II subgroup. Fourteen patients of the whole sample (35.9%) had clinically significant open-bite relapse (negative overbite). CONCLUSIONS There was a statistically significant open-bite relapse in the overall sample and in the Class I-II subgroup. The clinically significant values of long-term open-bite correction stability were 64.11%, 47.82%, and 87.50% in the overall sample, the Class I-II subgroup, and the Class III subgroup, respectively.

Influence of root parallelism on the stability of extraction-site closures.

INTRODUCTION In premolar extraction cases, root parallelism is recommended to preserve the stability of space closures. The influence of the degree of root parallelism on relapse of tooth extraction spaces has been a controversial topic in the literature. The aim of this study was to compare the angle between the long axes of the canine and the second premolar in patients with and without stability of extraction-space closures. METHODS A sample of 56 patients, treated with 4 premolar extractions, was divided into 2 groups: group 1, consisting of 25 patients with reopening of extraction spaces; and group 2, consisting of 31 patients without reopening of extraction spaces. Panoramic radiographs of each patient were analyzed at the posttreatment and 1-year posttreatment stages. The data were statistically analyzed by using chi-square tests, t tests, analysis of variance (ANOVA), and Pearson correlation coefficients. RESULTS The results showed that the groups did not differ regarding the angle between the canine and the second premolar, and there was no correlation between angular changes and reopening of extraction spaces, showing that dental angular changes are not determining factors for relapse, and other factors should be investigated. CONCLUSIONS The final angle and the posttreatment changes observed in the angle between the long axes of the canine and the second premolar showed no influence on the relapse of extraction spaces.

Class I malocclusion treatment: Influence of a missing mandibular incisor on anterior guidance

This case report describes the orthodontic treatment of a patient with a deep-overbite Angle Class I malocclusion, agenesis of a mandibular central incisor, and 2 supernumerary teeth, which caused impaction of the mandibular first premolars. The 15-year-old patient also had a convex profile, maxillary dentoalveolar protrusion, and deficiency of space for the correct alignment of teeth. Therefore, treatment consisted of fixed appliance therapy, cervical headgear, extraction of the supernumeraries and the mandibular and maxillary first premolars, and mesiodistal reduction of the maxillary incisors to solve the arch perimeter discrepancy as much as possible with interproximal stripping. This method of treatment significantly improved the patients facial and dental esthetics and provided a good functional occlusion, despite the absence of a mandibular incisor, which generally impairs achieving adequate incisal guidance.

Class III subdivision malocclusion corrected with asymmetric intermaxillary elastics

Correcting a Class III subdivision malocclusion is usually a challenge for an orthodontist, especially if the patients profile does not allow for any extractions. One treatment option is to use asymmetric intermaxillary elastics to correct the unilateral anteroposterior discrepancy. However, the success of this method depends on the individual response of each patient and his or her compliance in using the elastics. The objectives of this article were to present a successful treatment of a Class III subdivision patient with this approach and to illustrate and discuss the dentoskeletal changes that contributed to the correction.

Variáveis relevantes no tratamento da má oclusão de Classe II

Results of orthodontic Class II malocclusion treatment can be influenced by inherent characteristics such as patient age, malocclusion severity and degree of compliance, or even by factors regarding the orthodontists subjective preference such as the treatment protocol. Basically, Class II treatment protocols involve nonextraction or extraction of two or four premolars. However, a greater treatment success rate can be expected with the extraction protocol of two maxillary premolars, regardless of the skeletal pattern or the amount of maxillomandibular anteroposterior discrepancy. According to this review, it was concluded that Class II malocclusion treatment results are strongly influenced by the treatment protocol, while skeletal characteristics do not seem to exert significant influence.

Orthodontic treatment alternative to a class III subdivision malocclusion

Class III malocclusions are considered one of the most complex and difficult orthodontic problems to diagnose and treat. Skeletal and/or dental asymmetries in patients presenting with Class III malocclusions can worsen the prognosis. Recognizing the dentoalveolar and skeletal characteristics of subdivision malocclusions and their treatment possibilities is essential for a favorable nonsurgical correction. Therefore, this article presents a nonsurgical asymmetric extraction approach to Class III subdivision malocclusion treatment which can significantly improve the occlusal and facial discrepancies.

Two-dimensional radiographic and clinical references of the tooth crown for orthodontic mini-implant insertion: a guide-free technique.

OBJECTIVE This study evaluated the reliability of tooth-crown radiographic references to aid in orthodontic mini-implant insertion and showed an insertion technique based on these references. STUDY DESIGN The sample consisted of 213 interradicular septa evaluated in 53 bitewing radiographs. The proximal contour of adjacent tooth crowns was used to define septum width and its midpoint was linked to the interdental contact point to determine septum midline (SML). The distances from SML to mesial and distal teeth were measured and compared to evaluate SML centralization degree in 2 different septum heights. RESULTS The mesial and distal distances were not statistically different in the midpoint of the septum height, but they were different at the apical septum height. CONCLUSIONS The tooth-crown radiographic references determine a high centralization degree of the SML on which an insertion site could be defined. The greater SML centralization degree was observed at the coronal septum area.

Influência da largura do septo inter-radicular sobre a estabilidade dos mini-implantes

OBJECTIVE: The purpose of this study was to evaluate the influence of the inter-radicular septum width in the insertion site of self-drilling mini-implants on the stability degree of these anchorage devices. METHODS: The sample consisted of 40 mini-implants inserted in the inter-radicular septum between maxillary second premolars and first molars in 21 patients to provide skeletal anchorage for anterior retraction. The post-surgical radiographs were used to measure the septum width in the insertion site (ISW). In this regard, the mini-implants were divided in two groups: group 1 (critical areas, ISW 3 mm). The degree of mobility (DM) was monthly quantified to determine mini-implant stability, and the success rate of these devices was calculated. This study also evaluated the sensitivity degree during miniscrew load, amount of plaque around the miniscrew, insertion height, and total evaluation period. RESULTS: The results showed no significant difference in mobility degree and success rate between groups 1 and 2. The total success rate found was 90% and no variable was associated with the miniscrew failure. Nevertheless, the results showed that greater patient sensitivity degree was associated to the mini-implant mobility and the failure of these anchorage devices happened in a short time after their insertion. CONCLUSION: Septum width in the insertion site did not influence the self-drilling mini-implant stability evaluated in this study.

Short-term impact of rapid maxillary expansion on ectopically and normally erupting canines

Introduction The purpose of this study was to evaluate the short‐term impact of rapid maxillary expansion (RME) on the eruption paths of ectopically and normally erupting maxillary canines in the mixed dentition. Methods Thirty‐two patients with 49 ectopically erupting canines (EEC group; age, 9.53 ± 1.10 years) and 18 patients with 27 normally erupting canines (NEC group; age, 9.25 ± 1.06 years) underwent RME. Thirty‐six subjects with 54 normally erupting canines composed the untreated control group (UC group; age, 9.03 ± 0.72 years). Horizontal, vertical, and angular positions of canines and adjacent teeth were evaluated in the expanded (EEC and NEC groups) and unexpanded (UC group) patients using panoramic radiographs taken at 2 times with a 1‐year interval. The radiographic evaluation methods included score ranking and proportional measurements to minimize panoramic radiograph limitations. Statistical comparisons were performed among the groups (P <0.05). Results Before expansion, the EEC groups canines were significantly closer to the midline, more distant from the occlusal plane, and more mesially angulated than those in the UC group. After expansion, the canine positions in the EEC and UC groups were similar, whereas the NEC group had a more favorable canine position for eruption. The EEC and NEC groups showed similar canine positional changes, whereas the UC group had the smallest changes. The positions of teeth adjacent to the canine were also significantly affected by RME, and these changes may be associated with improvement of the ectopic canine position. Conclusions The changes produced by RME reduced the percentage of ectopic eruption paths and maintained the nonectopic eruption percentage. HighlightsRME had a significant short‐term impact on position and eruption speed of canines.Canine eruption speed was faster after RME.Canine eruption path was more upright and farther from the midline after RME.Similar changes were seen in first premolar eruption path and speed.Changes in neighboring teeth may be associated with canine position improvement.