Int Orthod. 2016 Jun;14(2):143-60. doi: 10.1016/j.ortho.2016.03.015. Epub 2016 Apr 16.
NO ABSTRACT
PMID:27094736 | DOI:10.1016/j.ortho.2016.03.015
Int Orthod. 2016 Jun;14(2):143-60. doi: 10.1016/j.ortho.2016.03.014. Epub 2016 Apr 16.
ABSTRACT
AIMS: In order to compare the premaxilla and symphysis in Class I and Class III individuals, we measured the following parameters on CBCT scans: incisor inclination, symphyseal morphology, upper alveolar process morphology, symphyseal and maxillary leeway space, as well as anterior and posterior maxillary and mandibular bone thickness at various points below the cementoenamel junction.
MATERIALS AND METHODS: CBCT scans were taken of 62 individuals (41 females and 21 males) of ages ranging between 11 and 53years (mean 23.26). The dentoskeletal relationship and alveolar process morphology (thickness) were evaluated on axial slices of the upper and lower jaws, and Student’s parametric t-test for paired data was used to compare Class I and Class III values within different facial types.
RESULTS: Many significant differences in measurements between the two facial types were noted in terms of tooth inclination, alveolar thickness, and leeway space.
CONCLUSIONS: Our findings confirm that Class III patients have little periodontal support at the upper and lower incisors, irrespective of the amount of symphyseal leeway space available, and any tooth movement must therefore be carefully planned and monitored.
PMID:27094737 | DOI:10.1016/j.ortho.2016.03.014
Angle Orthod. 2017 Jan;87(1):11-18. doi: 10.2319/113015-813.1. Epub 2016 Jun 17.
ABSTRACT
OBJECTIVE: To investigate the stress release properties of four thermoplastic materials used to make orthodontic aligners when subjected to 24 consecutive hours of deflection.
MATERIALS AND METHODS: Four types of aligner materials (two single and two double layered) were selected. After initial yield strength testing to characterize the materials, each sample was subjected to a constant load for 24 hours in a moist, temperature-regulated environment, and the stress release over time was measured. The test was performed three times on each type of material.
RESULTS: All polymers analyzed released a significant amount of stress during the 24-hour period. Stress release was greater during the first 8 hours, reaching a plateau that generally remained constant. The single-layer materials, F22 Aligner polyurethane (Sweden & Martina, Due Carrare, Padova, Italy) and Duran polyethylene terephthalate glycol-modified (SCHEU, Iserlohn, Germany), exhibited the greatest values for both absolute stress and stress decay speed. The double-layer materials, Erkoloc-Pro (Erkodent, Pfalzgrafenweiler, Germany) and Durasoft (SCHEU), exhibited very constant stress release, but at absolute values up to four times lower than the single-layer samples tested.
CONCLUSIONS: Orthodontic aligner performance is strongly influenced by the material of their construction. Stress release, which may exceed 50% of the initial stress value in the early hours of wear, may cause significant changes in the behavior of the polymers at 24 hours from the application of orthodontic loads, which may influence programmed tooth movement.
PMID:27314603 | PMC:PMC8388588 | DOI:10.2319/113015-813.1
Am J Orthod Dentofacial Orthop. 2016 Jul;150(1):105-15. doi: 10.1016/j.ajodo.2015.12.021.
ABSTRACT
INTRODUCTION: The aims of this study were to confirm the efficacy of the Bolton index in a group of natural Class I white Italian patients with complete dentition, minimal crowding, and no previous orthodontic treatment, and to evaluate the mesiodistal tooth dimensions with multivariate cluster analysis.
METHODS: Tooth measurements were obtained from a sample of 56 patients with normal occlusion, with a normal Bolton index (22 men, 34 women; mean age, 27.8 years), without previous orthodontic treatment or prosthetic or Class II restorations. Maxillary and mandibular measurements were analyzed separately in the sexes. Clustering was performed using the partitioning around medoid algorithm and principal component analysis-based transformed data. Statistical analysis was conducted.
RESULTS: The multivariate analysis showed 3 distinct clusters of both maxillary and mandibular tooth measurements in the male and female subjects. Statistically significant differences were found between the sexes in terms of average tooth measurements, and there was significant proportionality between the maxillary and mandibular arch clusters.
CONCLUSION: Although the Bolton index is useful for identifying dentodental discrepancies in most patients, cluster analysis enabled the mandibular and maxillary tooth dimensions of the male and female subjects to be divided into 3 general classes (clusters) and the precise location of the discrepancies to be pinpointed.
PMID:27364212 | DOI:10.1016/j.ajodo.2015.12.021
J Oral Facial Pain Headache. 2016 Summer;30(3):249-54. doi: 10.11607/ofph.1616.
ABSTRACT
AIMS: To determine whether there is a correlation between any psychological features and sleep bruxism (SB).
METHODS: A total of 36 healthy volunteers underwent an in-home evaluation with a portable device combining electromyographic (EMG) and electrocardiographic (ECG) recordings for the diagnosis of SB. They were administered questionnaires that assessed state and trait anxiety levels and coping strategies. The study hypothesis was that the SB index was significantly correlated with an individual’s anxiety and coping. Correlation between SB index and psychological features was assessed and a comparison between SB prevalences in subjects with different psychological scores was carried out.
RESULTS: Correlation analysis showed that the SB index was not correlated with any of the psychological scales; however, there were some significant correlations (r values range from 0.393 to 0.458) between the SB index and specific items from the trait anxiety and coping scales. Crosstabulations of subjects with SB and with high (overmedian) or low (undermedian) scores for the various psychological measures revealed significant correlations between the prevalence of SB in higher-scoring subjects for state anxiety scores (Phi coefficient = .456; P = .006), trait anxiety scores (Phi = 0.369; P = .027), and social support coping strategy (Phi = 0.387; P = .020).
CONCLUSION: These findings support the study hypothesis only in part and confirm the absence of a clear-cut relationship between SB and psychological features.
PMID:27472528 | DOI:10.11607/ofph.1616
Angle Orthod. 2017 Jan;87(1):88-95. doi: 10.2319/020616-104.1. Epub 2016 Aug 10.
ABSTRACT
OBJECTIVE: To conduct an objective assessment of the level of compliance in young patients prescribed various types of removable appliances and to determine the influence of device type, treatment duration, and patient age, gender, psychological maturity, and awareness of monitoring on compliance.
MATERIALS AND METHODS: A total of 30 patients were fitted with either a class 2 (Frankel or bionator) or a class 3 (face mask) removable appliance, each bearing a compliance indicator chip, and they were instructed to wear them for 13 hours per day. Compliance was monitored by means of the sensor for an average of 8 months. Of the patients, 14 were informed that their appliance was fitted with a monitoring sensor, and 16 were not. The psychological maturity of all patients was assessed on the Nowicki-Strickland Locus of Control Scale, and the effect on compliance of this score as well as the patient- and treatment-related variables considered were determined via statistical analysis Results: The mean compliance recorded by the chips was 8.6 ± 2.9 hours, far lower than the 13 hours prescribed, and younger patients showed significantly greater compliance than adolescents (P < .01). However, no significant differences in compliance were found between intra- and extraoral appliances, and neither gender, psychological scores, treatment duration, nor awareness of being monitored had any significant effect.
CONCLUSIONS: Compliance is generally very poor in young patients, regardless of their gender and psychological maturity. Although awareness of monitoring does not appear to boost compliance, such systems may be a valuable means of providing a dentist with objective information regarding their patients’ compliance.
PMID:27508935 | PMC:PMC8388593 | DOI:10.2319/020616-104.1
Am J Orthod Dentofacial Orthop. 2016 Sep;150(3):416-24. doi: 10.1016/j.ajodo.2016.02.025.
ABSTRACT
INTRODUCTION: The aims of the study were to determine how a panel of orthodontists, dentists, and laypersons rated the esthetic appeal of dentitions after orthodontic space closure by canine substitution compared with space opening and replacement of missing maxillary lateral incisors by implant-borne crowns and to compare the outcome with the results of a study in the United States in 2005.
METHODS: A series of 9 posttreatment intraoral frontal photographs was presented to 87 orthodontists, 100 general dentists, and 100 laypersons. The photographs represented dentitions with either single-tooth implants or canine substitutions for missing maxillary lateral incisors and dentitions with no missing teeth. Each photograph was rated independently by assigning a number between 1 (best) and 5 (worst) for a series of 7 bipolar adjectives. Two-way analysis of variance and Tukey post hoc tests were performed to assess differences in intragroup and intergroup preferences for the various treatment options. Subsequently, the mean scores were compared with the mean scores in the study from 2005.
RESULTS: Highly significant improvements (P <0.0001) in the esthetic outcome for implants were found in all respondent groups when compared with the study from 2005. To date, orthodontists and dentists rank implants and canine substitution as equally pleasing, but laypersons prefer space closure.
CONCLUSIONS: Perceptions of dental esthetics can vary between dental professionals and laypersons. Investigating each patient’s esthetic expectations is thus important, but in the patient’s best interest, esthetic and functional aspects should be carefully weighed during comprehensive treatment planning.
PMID:27585769 | DOI:10.1016/j.ajodo.2016.02.025
Prog Orthod. 2016 Dec;17(1):27. doi: 10.1186/s40510-016-0140-2. Epub 2016 Sep 12.
ABSTRACT
BACKGROUND: The aim of this study is to investigate the relative stiffness of straight and mushroom lingual archwires of different diameters, cross sections and alloys, plotting their load/deflection graphs and using a modified three-point bending test.
METHODS: Fujita’s mushroom archwires and straight lingual archwires of different diameters, cross sections and alloys were derived by a virtual set-up of an equal malocclusion and were cut at their straight distal portion. These distal portions were tested using a modified three-point bending test by an Instron 4467 dynamometer and the forces, were exerted at 1-mm deflection and were compared on each resulting load/deflection curve by means of ANOVA (p < 0.05).
RESULTS: All upper lingual mushroom wires exerted significantly lower forces than the straight wire. Lower mushroom archwires were stiffer than their upper counterparts, which were longer and featured inset bends. In the lower arch, similar levels of forces were recorded for the two types of wire. Load-deflection curves were higher for the straight wires, and stiffness increased proportionally with their diameter.
CONCLUSIONS: The stiffness of an archwire is a function of its diameter, length and the alloy it is made from. In lower lingual wires, there is little difference in stiffness between mushroom and straight wires, but in upper wires, the straight version is considerably stiffer. The greater bearing effect exhibited by the straight wire in the working and finishing phases makes it less susceptible to bowing effect and therefore preferable for sliding mechanics during en masse retraction, particularly in the upper arch.
PMID:27593408 | PMC:PMC5018471 | DOI:10.1186/s40510-016-0140-2
Prog Orthod. 2016 Dec;17(1):28. doi: 10.1186/s40510-016-0142-0. Epub 2016 Sep 19.
ABSTRACT
BACKGROUND: The treatment options for the early treatment of anterior open bite are still controversial. The aim of this study was to evaluate the actual available evidence on treatments of anterior open bite in the mixed dentition in order to assess the effectiveness of the early treatment in reducing open bite, the most efficacious treatment strategy and the stability of the results.
MATERIALS AND METHODS: A literature survey was done on November 15, 2015, by means of appropriate Medical Subject Headings (MeSH) using the following databases: PubMed, EMBASE, Cochrane Library, LILACS, VHL, and WEB OF SCIENCE. Randomized clinical trials and studies with a control group (treated or untreated) were then selected by two authors. Trials including patients with syndromes or in the permanent dentition and studies concerning treatment with extractions, full-fixed appliances, or surgery were not considered. Full articles were retrieved for abstracts or titles that met the initial inclusion criteria or lacked sufficient detail for immediate exclusion.
RESULTS: Two thousand five hundred sixty-nine studies about open bite were available; the search strategy selected 240 of them. Twenty-four articles have been judged suitably for the final review, and their relevant data were analyzed.
DISCUSSION: Although this review confirms the effectiveness of early treatment of open bite, particularly when no-compliance strategies are employed, meta-analysis was unfeasible due to lack of standardization, important methodological limitations, and shortcomings of the studies.
CONCLUSIONS: A more robust approach to trial design in terms of methodology and error analysis is needed. Besides, more studies with longer periods of follow-up are required.
PMID:27615261 | PMC:PMC5027197 | DOI:10.1186/s40510-016-0142-0
Prog Orthod. 2016 Dec;17(1):36. doi: 10.1186/s40510-016-0151-z. Epub 2016 Nov 28.
ABSTRACT
BACKGROUND: The aim of this study is to evaluate the mechanical properties of the screws used for rapid expansion of the upper jaw.
METHODS: Ten types of expansion screw were assessed, seven with four arms: Lancer Philosophy 1, Dentaurum Hyrax Click Medium, Forestadent Anatomic Expander type “S”, Forestadent Anatomic Expander type “S” for narrow palates, Forestadent Memory, Leone A 2620-10 with telescopic guide, and Leone A 0630-10 with orthogonal arms; and three with two arms: Dentaurum Variety S.P., Target Baby REP Veltri, and Leone A 362113. A test expander with the mean dimensions taken from measurements on a sample of 100 expanders was constructed for each screw. The test expanders were connected to the supports of an Instron 4467 (Instron Corp., USA) mechanical testing machine equipped with a 500 N load cell, and the compression force exerted after each activation was measured. The mean forces expressed by the two- and four-arm expanders were then compared.
RESULTS: After five activations, the forces expressed by the two-arm devices were double than those expressed by the four-arm devices on average (224 ± 59.9 N vs. 103 ± 32.9 N), and such values remained high after subsequent activations.
CONCLUSIONS: The expanders tested demonstrated stiffness characteristics compatible with opening of the palatine sutures in pre-adolescent patients. The stiffness of such devices can be further increased during the construction phase.
PMID:27747528 | PMC:PMC5124561 | DOI:10.1186/s40510-016-0151-z