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The article investigates the wear and friction properties of oscillating strips used for interproximal enamel reduction (IPR) to validate the importance of a standardized sequence for preserving efficiency and lifetime. Topics discussed include the mechanical and tribological evaluation of the strips, qualitative and quantitative assessments of wear patterns, and the impact of prolonged usage on strip performance.

To evaluate tooth movements during maxillary arch expansion with clear aligner treatment. The study group included 28 subjects (16 females, 12 males, mean age 31.9 ± 5.4 years) collected prospectively from January 2018 to May 2019. Inclusion criteria were European ancestry, posterior transverse discrepancy of 3–6 mm, permanent dentition stage, presence of second permanent molars, mild or moderate crowding, and good compliance with aligners. Treatment protocol included nonextraction strategies, application of Invisalign clear aligner system, and no auxiliaries other than Invisalign attachments. Linear and angular measurements were performed before treatment (T1), at the end of treatment (T2), and on final virtual models (T2 ClinCheck). A paired t-test was used to compare T2-T1 and T2-T2 ClinCheck changes. The level of significance was set at 5%. Statistically significant differences were found for all measurements, except for ones at the upper second molars. The greatest increase in maxillary width was detected at the upper first and second premolars: +3.5 mm for the first premolar and +3.8 mm for the second premolar at T2. Comparison of T2-T1 angular outcomes showed statistically significant changes in the inclinations of all teeth except for the second permanent molars. T2-T2 ClinCheck showed significant differences for both linear and angular measurements for maxillary canines, resulting in poor predictability. Maxillary arch development revealed a progressive reduction of the expansion rate and buccal tipping in the anterior, lateral, and posterior regions, with the greatest net increase at the first and second premolars. Clinical attention should be paid to maxillary canine movements, and overcorrection should be planned for them during dentoalveolar expansion. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the long-term effects of rapid maxillary expansion (RME) and posterior bite block (BB) in prepubertal subjects with dentoskeletal open bite. Materials and Methods: The treatment group (TG) comprised 16 subjects (14 girls, 2 boys) with dentoskeletal open bite with a mean age of 8.1 ± 1.1 years treated with RME and BB. Three consecutive lateral cephalograms were available before treatment (T1), at the end of the active treatment with the RME and BB (T2), and at a follow-up observation at least 4 years after the completion of treatment (T3). The TG was compared with a control group (CG) of 16 subjects (14 girls, 2 boys) matched for sex, age, and vertical skeletal pattern. An independent sample t-test was used to compare the T1 to T3, T1 to T2, and T2 to T3 cephalometric changes between the TG and the CG. Results: In the long term, the TG showed a significantly greater increase in overbite (+1.8 mm), reduced extrusion of maxillary and mandibular molars (−3.3 mm), and, consequently, a significant decrease in facial divergence (−2.8°) when compared with untreated subjects. Conclusions: The RME and BB protocol led to successful and stable recovery of positive overbite in 100% of the patients considered. Correction of open bite was associated with reduced extrusion of maxillary and mandibular molars with a significant improvement in vertical skeletal relationships when compared with the CG. [ABSTRACT FROM AUTHOR]

The article presents a study regarding the use of tribological testing and scanning electronic microscope (SEM) to test in vitro and in vivo the wear performance of diamond-coated strips. The study performed tribological test was using a standard tribometer, in which the abrasive strips slid against stationary. The study showed that the diamond-coated strips presented a fenestrated structure characterized by diamond granules alternating with voids.

The article presents a study which focuses on the use of three-dimensional (3D) analysis to analyze variations in palatal morphology in patients with unilaterally impacted maxillary permanent central incisors compared with a control group (CG) without eruption anomalies. The study examined 26 patients unilaterally impacted maxillary permanent central incisors. The results revealed that patients with impacted maxillary incisors showed skeletal adaptations of the maxilla.

Objective: To investigate the influence of two different activation protocols on the timing and intensity of pain during rapid maxillary expansion (RME). Materials and Methods: A total of 112 prepubertal patients (54 males and 58 females, mean age 11.00 ± 1.80 years) with constricted maxillary arches underwent RME with two different activation protocols (group 1: one activation/day; group 2: two activations/day). Patients were provided with a numeric rating scale (NRS) and the Faces Pain Scale (FPS) to correctly assess their daily pain. Results: Subjects treated with RME at two activations/day reported statistically significantly greater amounts of pain than subjects treated with RME at one activation/day. Differences related to gender and skeletal maturity were found. Conclusion: The choice of activation protocol influences the perceived pain during RME, and less daily expansion is correlated to less pain. Pain reported during RME could be influenced by skeletal maturity and gender of the subjects under treatment. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the dentoskeletal short-term effects of rapid maxillary expansion and facemask therapy (RME/FM) in a sample of Class III patients showing different vertical skeletal relationships. Materials and Methods: Seventy-nine patients (35 females and 44 males) having Class III malocclusion were consecutively treated using RME/FM therapy with application of the protraction force in a downward and forward direction and inclination of about 30° to the occlusal plane. All patients were evaluated at the beginning (T1; mean age, 7.7 years) and at the end (T2; mean age, 9.2 years) of orthopedic therapy and divided into three groups according to their vertical skeletal relationships: normal group (NG), hypodivergent group (HypoG), and hyperdivergent group (HyperG). Statistical comparisons between the three groups were performed on the starting forms (T1), the final forms (T2), and the treatment changes (T1–T2) using the ANOVA with Tukey’s post hoc tests. Results: Favorable modification in terms of maxillary advancement (changes in SNA ranging from 1.4° to 1.8°) and intermaxillary sagittal skeletal relationships (changes in Wits appraisal ranging from 2.5 mm to 3.5 mm) were recorded in all groups. The three groups showed no statistically significant differences in changes in either sagittal or vertical skeletal variables. Conclusions: The various vertical skeletal features do not influence the short-term outcomes of RME/FM therapy. [ABSTRACT FROM AUTHOR]

Objective: To analyze the long-term skeletal and dentoalveolar effects and to evaluate treatment timing of Class II treatment with functional appliances followed by fixed appliances. Materials and Methods: A group of 40 patients (22 females and 18 males) with Class II malocclusion consecutively treated either with a Bionator or an Activator followed by fixed appliances was compared with a control group of 20 subjects (9 females and 11 males) with untreated Class II malocclusion. Lateral cephalograms were available at the start of treatment (mean age 10 years), end of treatment with functional appliances (mean age 12 years), and longterm observation (mean age 18.6 years). The treated sample also was divided into two groups according to skeletal maturity. The early-treatment group was composed of 20 subjects (12 females and 8 males) treated before puberty, while the late-treatment group included 20 subjects (10 females and 10 males) treated at puberty. Statistical comparisons were performed with analysis of variance followed by Tukey's post hoc tests. Results: Significant long-term mandibular changes (Co-Gn) in the treated group (3.6 mm over the controls) were associated with improvements in the skeletal sagittal intermaxillary relationship, overjet, and molar relationship (-3.0-3.5 mm). Treatment during the pubertal peak was able to produce significantly greater increases in total mandibular length (4.3 mm) and mandibular ramus height (3.1 mm) associated with a significant advancement of the bony chin (3.9 mm) when compared with treatment before puberty. Conclusion: Treatment of Class II malocclusion with functional appliances appears to be more effective at puberty. (Angle Orthod. 2013;83:334-340.) [ABSTRACT FROM AUTHOR]

Objective: To assess the scientific evidence that rapid maxillary expansion (RME) causes Adverse Effects on the midpalatal suture, vertical dimension, dental and periodontal structures in growing subjects. Materials and Methods: Electronic databases were searched for articles dated through December 2011. The quality of the studies was ranked on a 13-point scale in which 1 was the low end of the scale and 13 was the high end. Results: Thirty relevant articles were identified. The amount of midpalatal suture opening ranged from 1.6 to 4.3 mm in the anterior region and from 1.2 to 4.4 mm in the posterior region. At the end of the active phase, RME resulted in slight inferior movement of the maxilla (SN-PNS +0.9 mm; SN-ANS +1.6 mm), increased tipping of anchored teeth from 3.4° to 9.2° and bending of the alveolar bone from 5.1° to 11.3°. In the long term, RME did not modify the facial growth patterns, and no significant changes on dentoalveolar structures were observed. Of the 30 studies, 2 were medium-high quality, 8 were medium quality, and 20 were low quality. Conclusions: RME always opened the midpalatal suture in growing subjects. The vertical changes were small and transitory. In the long-term evaluation, an uprighting of anchored teeth was observed and periodontal structures were not compromised. [ABSTRACT FROM AUTHOR]

Objective: To determine the effectiveness of orthodontic treatment finalized on the maintenance/ improvement the upper arch perimeter to assist in the successful eruption of palatally displaced maxillary canines (PDCs). Materials and Methods: The randomized prospective design comprised 64 subjects with PDCs who were randomly assigned to one of three groups: cervical pull headgear (HG); rapid maxillary expansion and cervical pull headgear (RME/HG); or untreated control group (CG). Panoramic radiographs and lateral cephalograms were evaluated at the time of initial observation (T1) and after an average period of 18 months (T2). At T2 the success of canine eruption was evaluated. A superimposition study on lateral cephalograms was undertaken to evaluate the T1-T2 changes in the sagittal position of the upper molars in the three groups. Results: The prevalence of successful eruption was 85.7% in the RME/HG group and 82.3% in the HG group. Both these prevalence rates were significantly greater than the success rate in untreated control subjects (36%). The cephalometric superimposition study showed a significant mesial movement of the upper first molars in the CG compared with the HG and RME/HG groups. Conclusions: The use of rapid maxillary expansion and headgear (or headgear alone) in PDC cases increases the success rate of eruption of the canine significantly (almost three times more than in untreated controls). (Angle Orthod. 2011;81:370-374.) [ABSTRACT FROM AUTHOR]

Objective: To apply both conventional cephalometric analysis and morphometric analysis (thin-plate spline analysis) to posteroanterior (PA) cephalograms to test the hypothesis that the dentoskeletal features of subjects with anterior open bite in the mixed dentition are no different from those of normal controls. Materials and Methods: A group of 22 white subjects (6 males, 16 females; mean age, 8.7 ± 0.7 years) with anterior open bite (AOBG) was compared with a control group (CG) of 22 white subjects (11 males, 11 females; mean age, 9.2 ± 0.8 years) with Class I occlusal relationships, and without anterior open bite and sucking habits. Subjects of both groups were in the mixed dentition and had no history of orthodontic treatment. Between-group statistical comparisons were performed with independent sample t-tests and permutation tests. Results: AOBG exhibited statistically significant shape differences with respect to CG that consisted of a transverse contraction of the zygomatic region, of the maxilla (at both skeletal and dentoalveolar levels), and of the mandible (in both condylar and gonial regions), with a downward dislocation of point menton. With conventional cephalometrics, AOBG showed a statistically significant transverse deficiency in the zygomatic region (-4.8 mm), in the maxilla at both skeletal and dentoalveolar levels (-2.0 mm and -3.0 mm, respectively), and in the mandible in both condylar and gonial regions (-3.6 mm and -4.0 mm, respectively). Conclusion: Subjects with anterior open bite showed transverse deficiencies in the zygomatic region, in the maxilla, and in the mandible when compared with normal subjects. [ABSTRACT FROM AUTHOR]

Objective: To determine by low-dose computed tomography (CT) protocol the dental and periodontal effects of rapid maxillary expansion (RME). Materials and Methods: The sample comprised 17 subjects (7 males and 10 females), with a mean age at first observation of ii .2 years. Each patient underwent expansion of 7 mm. Multislice CT scans were taken before rapid palatal expansion (T0), at the end of the active expansion phase (T1), and after a retention period of 6 months (T2). On scanned images, measurements were performed at the dental and periodontal levels. Mean differences between measurements at T0, T1, and T2 were examined through analysis of variance (ANOVA) for repeated measures with post-hoc tests. Results: All interdental transverse measurements were significantly increased at both Ti and T2 with respect to T0. In the evaluation of T0-T1 changes, periodontal measurements were significant on the bucca) aspect of banded teeth with a reduction in alveolar bone thickness corresponding to the mesial (-0.5 mm; P < .05) and distal (-0.4 mm; P < .05) roots of the right first molar and to the mesial root of the left first molar (-0.3 mm; P < .05). In the evaluation of overall T0-T2 changes, the lingual bone plate thickness of both first molars was found to be significantly increased (+0.6 mm; P < .05). Conclusions: RME therapy induces a significant increase in the transverse dimension of the maxillary arch in growing subjects without causing permanent injury to the periodontal bony support of anchoring teeth discernible on CT imaging. [ABSTRACT FROM AUTHOR]

Objective: To identify the stability factors of skeletal Class III malocclusion after double-jaw surgery by a systematic review of the literature. Materials and Methods: The survey covered the period from September 1959 to October 2007 and used the MESH, Medical Subject Headings. The inclusion criteria were stability of bimaxillary surgery of the permanent dentition, adult patients with skeletal Class Ill malocclusion, a follow-up of at least 12 months, randomized and nonrandomized controlled clinical trials (RCCTs; CCTs), prospective and retrospective studies with and without concurrent untreated as well as normal controls, and clinical trials (CTs) comparing at least two treatment strategies without any untreated or normal control group. Results: The search strategy resulted in 1783 articles. After selection according to the inclusion/ exclusion criteria, 15 articles qualified for the final review analysis. Quality was low in two studies, medium in twelve, and medium/high in one article, which was represented by a RCT (randomized clinical trial). Most of the studies had sufficient sample size, method error analysis, and adequate statistical methods. Thus, the quality level of the studies was sufficient to draw evidence-based conclusions. Conclusions: Surgical correction of skeletal Class III malocclusion after combined maxillary and mandibular procedures appears to be stable for maxillary advancements up to 5 mm and for the correction of presurgical sagittal intermaxillary discrepancies smaller than 7 mm. [ABSTRACT FROM AUTHOR]

Objective: To assess the scientific evidence on the effectiveness of early orthopedic treatment in Class III subjects. Materials and Methods: A literature survey was performed by applying the Medline database (Entrez PubMed). The survey covered the period from January 1966 to December 2005 and used the Medical Subject Headings (MESH). The following study types that reported data on the effects of Class III treatment with orthopedic appliances (facial mask, chincup, FR-3) on intermaxillary sagittal and vertical relationships were included: randomized clinical trials (RCTs), and prospective and retrospective longitudinal controlled clinical trials (CCTs) with untreated Class III controls. Results: The search strategy resulted in 536 articles. After selection according to criteria for inclusion and exclusion, 19 articles qualified for the final review analysis. One RCT and 18 CCTs were retrieved. Conclusion: The quality standard of the retrieved investigations ranged from low (four studies) to medium/high (five studies). Data derived from medium/high quality research described over 75% of success of orthopedic treatment of Class III malocclusion (RME and facial mask therapy) at a follow-up observation 5 years after the end of orthopedic treatment. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effects of the quad-helix/crib (Q-H/C) appliance in subjects with thumb-sucking habits and dentoskeletal open bite at 2 years after the end of active treatment. Materials and Methods: The records of 21 subjects treated with the Q-H/C appliance were compared with a control group of 21 untreated subjects with similar vertical relationships. Lateral cephalograms were obtained before treatment (T1; mean age 8.4 ± 1.4 years) and at about 2 years after treatment (T2; mean age 11.7 ± 1.9 years) and analyzed. Mean treatment duration was 1.5 years ± 7 months. The T2-T1 changes in the two groups were compared with a nonparametric test for independent samples. Results: The mean increase in overbite during Q-H/C therapy (4.1 ram) represented an overcorrection of the amount of anterior open bite at T2. Both the maxillary and mandibular incisors showed significantly greater extrusion in the Q-H/C group than in the control group. The treated group showed a greater downward rotation (1.8°) of the palatal plane than did the control group. This change was associated with a clinically significant reduction in the palatal plane/mandibular plane angle (-2.5°) in the Q-H/C group. The upper lip showed significant retraction relative to the E-plane in the treated group (3.6 mm) compared with the controls. Conclusions: The Q-H/C appliance was effective in correcting dental open bite in 85% of the growing subjects with thumb-sucking habits and dentoskeletal open bites. Correction of anterior open bite was associated with a clinically significant improvement in maxillomandibular vertical skeletal relationships. [ABSTRACT FROM AUTHOR]

Objective: To compare the shear bond strength of different metal orthodontic brackets. Materials and Methods: Five types of orthodontic metal brackets were selected (S1, Victory Series, 3M Unitek, Monrovia, Calif; S2, Mini Dyna-Lock, 3M Unitek; S3, Mini Sprint, Forestadent, Pforzheim, Germany; S4, Topic, Dentaurum, Inspringen, Germany; and S5, equilibrium 2, Dentaurum). Brackets were bonded on enamel surfaces of bovine incisors (Transbond XT, 3M Unitek) and were tested for shear bond strength with an Instron universal testing machine (Instron Corp, Canton, Mass). Data obtained in newtons and megapascals were analyzed with descriptive statistics and with analysis of variance and Tukey honestly significant difference (HSD) tests. The adhesive fracture site was classified with the adhesive remnant index (ARI). Results: All the specimens tested had shear bond strength adequate to resist orthodontic forces. S5 showed significantly greater bond strength when compared with the other samples, except for S1. S1, S3, and S5 showed a significantly greater bonding force. The ARI index demonstrated a large variability. Retentive structure of S1, S3, and S5 had equal validity. The enlargement of the retentive surface enhances adhesion but affects the adaptability to surface irregularity of the enamel, increasing the risk of fracture at the interface with the bracket. Conclusions: The results of this study suggest that probably the retentive base extension can be lower than 7 mm² proposed in previous studies as the minimal area. [ABSTRACT FROM AUTHOR]

The aim of this study was a systematic review of the literature to assess the scientific evidence on the actual outcome of early treatments of open-bite malocclusions. A literature survey was done by applying the Medline database (Entrez PubMed). The survey covered the period from January 1966 to July 2004 and used the MeSH, Medical Subject Headings. The following study types that reported data on the treatment effects included: randomized clinical trials (RCT), prospective and retrospective studies with concurrent untreated as well as normal controls, and clinical trials comparing at least two treatment strategies without any untreated or normal control group involved. The search strategy resulted in 1049 articles. After selection according to the inclusionary/exclusionary criteria, seven articles qualified for the final review analysis. No RCTs of early treatment of anterior open bite have been performed. Two controlled clinical trials of early anterior open bite have been performed, and these two studies indicated the effectiveness of treatment in the mixed dentition with headgears or functional appliances (or both). Most of the studies had serious problems of lack of power because of small sample size, bias and confounding variables, lack of method error analysis, blinding in measurements, and deficient or lack of statistical methods. Thus, the quality level of the studies was not sufficient enough to draw any evidence-based conclusions. [ABSTRACT FROM AUTHOR]

This retrospective study (1) cephalometrically investigates the effectiveness of activator therapy, (2) evaluates the contribution of skeletal growth in the self-correction of the Class II malocclusion, and (3) analyzes separately the dental and skeletal responses to activator treatment and the differences between the incisor and molar areas. The subjects, all in the mixed dentition, were selected from a single center and were divided into a group of 40 Class II patients treated with an activator and an untreated group of 30 Class II patients. Dentoskeletal changes that occurred were compared on lateral cephalograms taken before the treatment/observation period and after 21 months (standard deviation, three months). When the activator patients were compared with the untreated control subjects, therapy promoted a combination of skeletal and dental changes that led to an improvement of the sagittal discrepancy. Other changes observed in the untreated Class II subjects did not bring about a correction of the malocclusion. An analysis of the corrective contributions in activator therapy in the posterior area showed that the orthopedic effects were greater than the dental effects in correcting the posterior occlusal relationship. In the anterior area of the arch, although both the skeletal and dental changes were favorable toward the sagittal correction, the skeletal contribution was greater than the dental contribution. In general, the skeletal contribution (140%) exceeded the dental correction (60%), and the mandibular changes (73%) exceeded the maxillary contribution (27%) both in the anterior and posterior regions. [ABSTRACT FROM AUTHOR]

A response from the author of the article "Short-term effects produced by rapid maxillary expansion and facemask therapy in Class III patients with different vertical skeletal relationships" that was published in the previous issue is presented.

A response from the author of the article "Long-term skeletal and dental effects and treatment timing for functional appliances in Class II malocclusion" in the 2013 issue is presented.

A response by Paola Cozza et al to a letter to the editor about their article "A Nonsurgical Approach to Treatment of High-Angle Class II Malocclusion" published in the previous issue is presented.