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Lab appliances are an integral part of orthodontics, from active treatment to retention. The quality and fit of an appliance can affect the treatment result and stability. AIMS: This study aims to determine common points of failure in orthodontic appliances, and suggest methods to reduce this rate. METHODS: A survey consisting of 23 questions was distributed to active members of the American Association of Orthodontists (AAO) via Survey Monkey. RESULTS: The most common appliance to need an adjustment was the wrap-around retainer, with the Hawley retainer as a close second. The least common appliance needing adjustment was the Essix/clear retainer. Respondents were asked which component of each appliance was most commonly responsible for an ill-fit. For Hawley and wrap-around retainers, clasps were the most common problem at 50%, whereas spring aligners had two components - clasps and labial bows, both at 38%. Ill-fitting Essix/clear retainers had gingival impingement (52%) closely followed by poor posterior seating (43%). CONCLUSIONS: Communication between the orthodontist and lab technician can be improved by establishing a quality assurance protocol for outgoing and incoming cases. The labial bow of Hawley's, wrap-arounds and spring aligners should be clearly demarcated on the casts. Impressions should be free of distortion and casts should be inspected for accuracy. Clear retainers and positioner should be trimmed to avoid gingival impingement. The type of clasp should be selected based on the anatomy of the teeth, and bands should be checked for accuracy of fit.

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Manufacturing of custom-made dental devices such as removable dentures, fixed prosthodontics and orthodontics are subject to the requirements of the Medical Devices Directive (MDD). Many dental laboratories often enhance these requirements by implementing quality assurance procedures that then provide enhanced consistency. This paper provided a personal view of some of the systems currently being used in dental laboratories to provide a quality assured product and associated issues.

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AIM: The purpose of this study was to analyze the cervico-occlusal dimensions of brackets used in lingual orthodontics for maxillary and mandibular central and lateral incisors, to compare them with the numbers informed by the manufacturer. MATERIALS AND METHODS: The brackets were placed in a template and analyzed by scanning electron microscopy (SEM), evaluating the images with the aid of a software that allowed determination of reference points, tracing of lines on the bracket images and measurement of the distances. RESULTS: Brackets manufactured by Dm Ceosa Hiro, Tecnident PSWb and Dentaurum Magic did not present statistically significant differences between the mean values of slot heights and the values informed by manufacturers. Conversely, the brands Ormco 7th generation, Ormco STb, GAC Innovation L, ORJ-ORG, Tecnident, Ormco STb LSW and Adenta evolution STL exhibited statistically significant differences. CONCLUSION: In general, there was a deficiency in the standar-dization of cervico-occlusal measurements of slots of the brackets analyzed. CLINICAL SIGNIFICANCE: Manufacturers should be attentive to the quality control of their materials. Future studies will analyze the actual clinical influence of these findings on the orthodontic mechanics.

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Incognito is a fully customized lingual fixed appliance system of high precision and limited adjustability. It is therefore important to incorporate as much detail as possible into the planning and communication of the appliance prescription. A systematic approach to this is suggested, breaking it down into torque, tip, tooth width and morphology, vertical tooth positioning, arch width and arch form. The clinician relies upon the laboratory technician to interpret correctly this guidance in the preparation of the set-up. Verification of the set-up by the clinician before appliance manufacture is not compulsory. The potential risks of not verifying the set-up are discussed.

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OBJECTIVE: The aim of the present study was to verify the torque precision of metallic brackets with MBT prescription using the canine brackets as the representative sample of six commercial brands. MATERIAL AND METHODS: Twenty maxillary and 20 mandibular canine brackets of one of the following commercial brands were selected: 3M Unitek, Abzil, American Orthodontics, TP Orthodontics, Morelli and Ortho Organizers. The torque angle, established by reference points and lines, was measured by an operator using an optical microscope coupled to a computer. The values were compared to those established by the MBT prescription. RESULTS: The results showed that for the maxillary canine brackets, only the Morelli torque (-3.33º) presented statistically significant difference from the proposed values (-7º). For the mandibular canines, American Orthodontics (-6.34º) and Ortho Organizers (-6.25º) presented statistically significant differences from the standards (-6º). Comparing the brands, Morelli presented statistically significant differences in comparison with all the other brands for maxillary canine brackets. For the mandibular canine brackets, there was no statistically significant difference between the brands. CONCLUSIONS: There are significant variations in torque values of some of the brackets assessed, which would clinically compromise the buccolingual positioning of the tooth at the end of orthodontic treatment.

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AIM: To discover the quality of written instructions from dentists to dental technicians and the nature of non-compliant prescriptions. METHOD: An audit of laboratory prescription compliance was conducted within an NHS Trust Dental Teaching Hospital to determine the level of communication between dentists and dental technicians. One hundred and fifty prescriptions were audited from dental undergraduates and qualified dentists throughout the different departments. RESULTS: A total of two-thirds of prescriptions were considered non-compliant and failed to meet relevant ethical and legal guidelines. This problem was seen throughout all departments and at all professional levels. CONCLUSION: A breakdown in communication between dentists and technicians through the use of prescriptions is evident even within a close working environment.

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OBJECTIVE: To evaluate the aesthetic colour performance (colour blending) of plastic and ceramic brackets by determining the colour changes of shade guide tabs before and after bracket placement. DESIGN: In vitro, laboratory study. MATERIALS AND METHODS: Four plastic and four ceramic brackets were investigated (n=5). Brackets were placed on the labial surface of the A1 and A4 tabs of a Vitapan classic shade guide. The colours of the areas corresponding to the central and inferior areas of the brackets were measured before and after bracket placement according to the CIELAB colour scale with a spectroradiometer. Changes in colour (ΔE*(ab)) and colour coordinates (ΔL*, Δa*, Δb* and ΔC*(ab)) of the tabs after bracket placement were calculated. RESULTS: Colour changes in the central and inferior areas were in the ranges of 5·6-11·1 and 4·3-12·3 ΔE*(ab) units, respectively. Changes in colour and colour coordinates were influenced by shade tab colour and bracket brand (P<0·05). Compared to A1 tab, ΔE*(ab), Δa*, Δb* and ΔC*(ab) values on A4 tab were significantly higher (P<0·01). The hybrid polymer bracket and glass reinforced plastic bracket induced the smallest colour changes in the central and inferior areas. CONCLUSIONS: All the investigated aesthetic brackets induced clinically unacceptable (ΔE*(ab)>5·5) or perceptible (ΔE*(ab)>2·6) colour changes when placed on the shade tabs. Aesthetic colour performance of brackets on the less chromatic and lighter tab was better than that on the more chromatic and dark tab. High translucency of bracket alone did not lead to better aesthetic colour performance.

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OBJECTIVE: The aim of the present study was to verify the torque precision of metallic brackets with MBT prescription using the canine brackets as the representative sample of six commercial brands. MATERIAL AND METHODS: Twenty maxillary and 20 mandibular canine brackets of one of the following commercial brands were selected: 3M Unitek, Abzil, American Orthodontics, TP Orthodontics, Morelli and Ortho Organizers. The torque angle, established by reference points and lines, was measured by an operator using an optical microscope coupled to a computer. The values were compared to those established by the MBT prescription. RESULTS: The results showed that for the maxillary canine brackets, only the Morelli torque (-3.33º) presented statistically significant difference from the proposed values (-7º). For the mandibular canines, American Orthodontics (-6.34º) and Ortho Organizers (-6.25º) presented statistically significant differences from the standards (-6º). Comparing the brands, Morelli presented statistically significant differences in comparison with all the other brands for maxillary canine brackets. For the mandibular canine brackets, there was no statistically significant difference between the brands. CONCLUSIONS: There are significant variations in torque values of some of the brackets assessed, which would clinically compromise the buccolingual positioning of the tooth at the end of orthodontic treatment.

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OBJECTIVE: To determine if there is a significant difference in the clinical outcomes of cases treated with 0.018-inch brackets vs 0.022-inch brackets according to the American Board of Orthodontics (ABO) Objective Grading System (OGS). MATERIALS AND METHODS: Treatment time and the ABO-OGS standards in alignment/rotations, marginal ridges, buccolingual inclination, overjet, occlusal relationships, occlusal contacts, interproximal contacts, and root angulations were used to compare clinical outcomes between a series of 828 consecutively completed orthodontic cases (2005-2008) treated in a university graduate orthodontic clinic with 0.018-inch- and 0.022-inch-slot brackets. RESULTS: A two-sample t-test showed a significantly shorter treatment time and lower ABO-OGS score in four categories (alignment/rotations, marginal ridges, overjet, and root angulations), as well as lower total ABO-OGS total score, with the 0.018-inch brackets. The ANCOVA-adjusting for covariants of discrepancy index, age, gender, and treatment time-showed that the 0.018-inch brackets scored significantly lower than the 0.022-inch brackets in both the alignment/rotations category and total ABO-OGS score. CONCLUSIONS: There were statistically, but not clinically, significant differences in treatment times and in total ABO-OGS scores in favor of 0.018-inch brackets as compared with the 0.022-inch brackets in a university graduate orthodontic clinic (2005-2008).

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BACKGROUND: Orthodontic treatment with fixed appliances requires - among others - the correct clinical expression of torque, which depends on the precise fitting of archwire and slot. Especially in the lingual technique torque problems become clinically more evident than in labial appliances also with respect to the vertical alignment of teeth due to different distances from the center of resistance. The purpose of the present study was to compare the preciseness of slot dimensions of different lingual bracket systems. METHODS: Three lingual bracket systems were included in the study (7th Generation and STb, Ormco, Glendora, CA, USA; Incognito, TOP-Service/3 M Unitek, Monrovia, CA, USA). Non destructive analysis of vertical slot dimensions was performed using precision pin gauges (Azurea, Belprahon, Switzerland) that were tapered in increments of 0.002 mm (0.00008 inch). The sizes of 240 incisor and canine brackets were measured per system (total: 720). Data were compared using one-way ANOVA. A p-value < 0.05 was considered statistically significant. RESULTS: Average slot dimensions were 0.467 mm +/- 0.007 mm (0.0184 inch +/- 0.0003 inch) for the 7th Generation bracket system, 0.466 mm +/- 0.004 mm (0.0183 inch +/- 0.0001) inch for the STb bracket system and 0.459 mm +/- 0.004 mm (0.0181 inch +/- 0.0001) inch for the Incognito bracket system. Differences between systems were statistically significant (p < 0.05). CONCLUSIONS: The analyzed bracket systems for lingual treatment exhibited significant differences in slot dimension that will clinically result in torque play. These aspects must be considered in lingual orthodontic treatment.

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OBJECTIVE: To present a comprehensive mathematical analysis of dental arch curvature in subjects with normal occlusion. MATERIALS AND METHODS: The materials studied were 40 sets of upper and lower plaster dental casts of subjects presenting with normal occlusion. The sample was equally divided into casts from male and female subjects with an age range from 18 to 25 years. Curve-fitting analyses was carried out and four main categories of functions were considered: the beta function, natural cubic splines, polynomial equations, and Hermite cubic splines. RESULTS: The polynomial function (fourth order) was found to be a reasonable analysis when the objective is to describe the general smooth curvature of the dental arch, while a Hermite cubic spline is more appropriate when it is desired to track arch irregularities, such as evaluating treatment changes. CONCLUSIONS: Due to its advantage in providing a more naturally smooth curve, the fourth-order polynomial function may be used as a guide to fabricate customized arch wires, or even an entire fixed orthodontic appliance system.

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Miniscrew placement has achieved widespread acceptance in orthodontic practice. However, selecting a suitable miniscrew system from among the available brands is not easy. The aim of this article is to help the clinician better understand the features of miniscrew systems currently available on the market and provide a useful guideline for their clinical use. The authors find that the ideal miniscrew design should include biocompatibility, bone-density-guided insertion, immediate loading, and compatibility with modern orthodontic accessories for 3-dimensional orthodontic control.

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The slots of five upper left central incisor brackets from 11 commercially available bracket systems (3M Unitek, Monrovia, Calif: Twin Torque Roth, Clarity MBT, and Victory Series MBT; Dentarum, Pforzheim, Germany: Discovery Roth (0.56 mm) and Elegance Plastic Roth; Forestadent, Pforzheim, Germany: Mini Mono MBT; TP LaPorte, Indiana: Nu-Edge Roth and Mxi Advant-Edge Roth; Ormco Corp., Orange, Calif: Damon II SL Roth; Ortho Organizers, San Marcos, Calif: Elite Mini Opti-MIM Roth and Elite Mini Opti-MIM MBT) were measured in the 0.022-inch (0.5588 mm) dimension. Measurements were taken after operator calibration, and a digital readout was produced. Results indicate that all bracket slots are oversized. Three bracket systems slots (Twin Torque, Clarity, and Mini Mono) were within 5% (+/-1.08, 1.655, 1.75) of their stated dimensions with essentially parallel slot walls. The Elegance Plastic slot was parallel sided but oversized by 12% (+/-1.15). The geometry of bracket slots was also variable. The Victory Series slot was slightly divergent with the top oversized by 6% (+/-1.035). The Nu-Edge slot was divergent and slot top oversized by 14% (+/-1.32). The Mxi Advant-Edge, Damon II SL, Elite Mini Opti-MIM Roth, and MBT were all convergent, and the base of the Damon slot was oversized by 17% (+/-1.79). The Discovery bracket was convergent, and the slot base was oversized by 24% (+/-1.255), which was the largest recorded variance. This bracket also had a 7% difference between the widths of the slot top and the base. Inaccurate machining of bracket slot dimensions and the use of undersized archwires may directly and adversely affect three-dimensional tooth positioning.

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