Objective vs subjective analyses of arch form and preformed archwire selection.

INTRODUCTION: Maintaining a patient's original arch form increases treatment stability. In this study, we assessed the agreement between subjective analyses of arch form and archwire selection by orthodontists and an objective method with Cast Analyzer Iranian X software (Khallaghane Mehr, Tehran, Iran). METHODS: Thirty-six casts with normal occlusion were scanned with a laser. The software generated the best-fit curve using a fourth-degree polynomial equation to the clinical bracket points on the casts; then it selected the best preformed nickel-titanium archwire based on the root mean square calculation either objectively or semiobjectively. Three orthodontists selected the best-fit curve and archwire subjectively using the casts. To assess intraexaminer reliability, the same orthodontists reevaluated 10 casts after 2 weeks. To assess interexaminer reliability, the 3 orthodontists performed the analyses with the software and on the casts. Agreements were evaluated with the intraclass correlation coefficient and Dahlberg's formula. RESULTS: The semiobjective method (visual selection of wire by orthodontists using the software) yielded the best results. The differences were clinically negligible between the objective (fully automated) and semiobjective methods (1.30 vs 1.36 mm). CONCLUSIONS: The objective method improved wire adaptation to the clinical bracket points. Agreement among orthodontists regarding wire selection will improve significantly when they are trained to use the software.

British Orthodontic Society national audit of temporary anchorage devices (TADs): report of the first thousand TADs placed.

OBJECTIVE: To provide data from the British Orthodontic Society (BOS) national clinical audit on temporary anchorage device (TAD) use following the recommendations of the National Institute for Health and Clinical Excellence (NIHCE) Design and setting: The Audit commenced on 1 January 2008 and is still ongoing. This article reports the data for TADs placed from 1 January 2008 to 1 November 2013. MATERIALS AND METHODS: Audit data was collected from participants using a system of both on-line data entry and hard copy forms. The criteria and standards for the audit were set following the NIHCE report in conjunction with the Development and Standards Committee of the BOS. Virtually all participants used the on-line data entry available on the BOS website. The data submitted was checked and entered manually into an Excel spreadsheet, and transferred to SPSS for analysis. RESULTS: Written information and documented discussion of risks were provided in over 90% of TADs placed, but 17.4% were placed without a specific signed consent form. Temporary anchorage device failure rate was 24.2% overall. Among failed TADs, 93.1% were lost or removed due to excess mobility. Infection or inflammation resulting in loss or removal was reported in 6% of TADs. CONCLUSIONS: The only audit standard that was met was failures due to infection of inflammation. The rest of the audit standards were not met. Recommendations are made to address these issues.

Accidental debondings: Buccal vs fully individualized lingual multibracket appliances.

INTRODUCTION: The aim of this study was to retrospectively assess the frequency and localizations of bond failures (BFs) in patients treated with either lingual (TOP-Service für Lingualtechnik GmbH, a 3M Company, Bad Essen, Germany) or buccal (Mini Diamond brackets/Accent molar tubes; Ormco, Orange, Calif) full multibracket appliances in both dental arches. METHODS: Data were acquired by an independent investigator from the patient records of 3 practitioners. To establish a standardized observation period, the first year of treatment was analyzed for each patient. Statistical analysis comprised the Kruskal-Wallis, Wilcoxon, Mann-Whitney U, and Fisher exact tests. The significance level was set at P <0.05. RESULTS: The mean number of BFs per patient in the first year of treatment did not differ significantly between the lingual group (n = 59; mean age, 31.1 years; mean BFs per patient, 2.63; SD, 2.77; minimum, 0; maximum, 13) and the buccal group (n = 44; mean age, 15.14 years; mean BFs per patient, 2.61; SD, 3.41; minimum, 0; maximum, 14) (P = 0.428) or with respect to sex (lingual group, P = 0.251; buccal group, P = 0.414) or practitioner (lingual group, P = 0.755; buccal group, P = 0.060), but molar attachments were more prone to BFs than were premolar brackets (lingual group, P = 0.015; buccal group, P = 0.049), and premolar brackets were more prone to BF than anterior brackets (lingual group, P = 0.005; buccal group, P = 0.004). CONCLUSIONS: With both appliances, a mean of 2.62 BFs per patient in the first year of treatment can be expected; this benchmark provides a reference for patient briefing, which is very important considering the large interindividual variances and budgeting considerations.

Interexaminer and intraexaminer reliabilities of 3-dimensional orthodontic digital setups.

INTRODUCTION: The use of digital orthodontic setups has grown quickly. The purpose of this study was to test the interexaminer and intraexaminer reliabilities of 3-dimensional orthodontic digital setups in OrthoCAD (Align Technology, San Jose, Calif). METHODS: Six clinicians made digital orthodontic setups on 6 digital models twice, with a minimum interval of 2 weeks and a maximum interval of 4 weeks. OrthoCAD software was used, and treatment goals were all set the same according to the American Board of Orthodontics Objective Grading System (ABO-OGS). Differences between the 72 setups were measured with the ABO-OGS scores. RESULTS: In comparing setups 1 and 2, the intraexaminer mean absolute differences in total ABO-OGS scores varied statistically significantly between 2.17 and 6.00 points. Interexaminer mean absolute differences varied statistically significantly between 4.77 and 5.56 points. All but 1 intraclass correlation coefficient (ICC) value showed significant excellent agreement (ICC, >0.8) for intraexaminer reliability. One ICC value was insignificant and showed moderate (ICC, 0.4-0.6) agreement. Interexaminer reliability showed significant good (ICC, 0.6-0.8) agreement. CONCLUSIONS: There is a significant difference in ABO-OGS score when using OrthoCAD. Although this difference was low, it could be clinically significant. Interexaminer and intraexaminer reliabilities are not redundant for general use of the 3-dimensional orthodontic digital setup in OrthoCAD.

An in vivo study on the incidence and location of fracture in round orthodontic archwires.

OBJECTIVE: The main objective of this in vivo study was to determine the incidence and location of fracture in round nickel-titanium (NiTi) and round stainless steel orthodontic archwires, both commonly used in orthodontics. Secondarily, this study sought to determine if there is any correlation between archwire fracture and gender, diameter of the archwire, arch type (maxillary/mandibular) or bracket used. DESIGN: In vivo study. MATERIALS AND METHODS: One thousand orthodontic patients (1434 archwires) were evaluated during regular treatment visits to assess archwire fracture and location. The patient's gender, age, type of archwire (round NiTi and round stainless steel), diameter of the archwire, arch type, location of fracture (anterior or posterior) and period of service before fracture were recorded. STATISTICAL ANALYSIS: Chi-square statistical test was utilized to address the frequency and the correlation between the different variables. Level of statistical significance (α) was set at 0.05. RESULTS: Twenty-five archwire failures were reported (1.7%) of the total sample size. All fractured archwires were NiTi, and 76% of the fractures were located in the posterior region. No statistical significance was found between archwire fracture and gender, arch type (maxillary/mandibular), archwire diameter or bracket type. CONCLUSION: The frequency of archwire fracture during regular orthodontic visits is very low. The most common archwire fracture site is the posterior region. NiTi wires are the most commonly fractured archwire. No statistically significant correlation exists between archwire fracture and gender, arch type, bracket type or diameter of archwire.

2013 survey of Australian orthodontists' procedures.

AIM: This survey of Australian orthodontists was conducted to assess treatment preferences. METHODS: Email invitations to participate in an online survey were sent to a total of 433 Australian Society of Orthodontists (ASO) members and 158 replies were received (36% response). RESULTS: For Class II treatment, most practitioners preferred to wait and treat later but when early treatment was performed, the Twin Block was the most popular appliance. For fixed appliance treatment, the 0.022 inch slot was the most commonly used (73%) and the median treatment time was 20 months. The median extraction rate was 23% which was similar to that reported in a 2008 USA survey. Sequential plastic aligners were used by 73% of respondents and Temporary Skeletal Anchorage Devices were used by 77%. The most common research question clinicians would like answered related to retention. CONCLUSION: The responses were similar Australia-wide but some areas of difference were revealed and discussed.

Evaluation of retention protocols among members of the American Association of Orthodontists in the United States.

INTRODUCTION: Little research has been conducted to evaluate protocols and trends in orthodontic retention. The purpose of this study was to identify the general retention protocols used by orthodontists in the United States. Additionally, our goal was to identify trends in these orthodontic retention protocols by evaluating how they have changed over the past 5 years and how they might continue to change in the next 5 years. METHODS: The study was conducted via a 36-question electronic survey (REDCap, Nashville, Tenn) with branching logic on certain questions. The survey was sent to all 9143 practicing members of the American Association of Orthodontists in the United States, and 1632 (18%) responded. RESULTS AND CONCLUSIONS: Mean retention protocols of the surveyed population showed predominant use of Hawley or vacuum-formed retainers in the maxillary arch and fixed retention in the mandibular arch. For both arches, there is a current shift away from Hawley retainers and toward vacuum-formed retainers and fixed retention. Respondents who extract fewer teeth reported increased use of fixed retention in the maxillary (P = 0.041) and mandibular (P = 0.003) arches. Respondents who extract fewer teeth and use removable retainers were more likely to tell their patients to wear their retainers at night for the rest of their lives (P = 1.63 × 10(-6)).

A survey on orthodontic retention procedures in The Netherlands.

The objective of this study was to survey retention procedures used in orthodontic practices in The Netherlands. A questionnaire was sent to all 279 orthodontists working in The Netherlands. The questionnaire consisted of six parts, mainly containing multiple-choice questions. Information as to background data on the individual orthodontist, retention in general, frequency of different types of removable or bonded retainers that were used, retention protocol, and the type and size of the wire used for bonded retainers was assessed. All statistical analyses were performed using Statistical Package for Social Sciences version 12.0.1. Tests for the relationship between two items were based on the chi-square test. The overall response rate was 91 per cent. Most orthodontists placed a bonded retainer in the upper and lower arch, except when the upper arch was expanded during treatment or when extractions were performed in the upper arch, in which case they placed a removable retainer. Opinions varied with regard to how many hours the removable retainers should be worn and the duration of the retention phase. Contraindications for bonded retainers were given by 96 per cent of the orthodontists, with poor oral hygiene being the most commonly mentioned. As far as bonded retainers were concerned, 84 per cent of the orthodontists preferred permanent retention. Fifty-nine per cent of the orthodontists believed that a practice guideline for retention after orthodontic treatment needs to be developed, which was confirmed by the varied responses in this survey.

Users' perceptions and preferences towards maxillary removable orthodontic retainers: a crossover randomized clinical trial.

The aim of this study was to assess, correlate, and compare users' perceptions and preference related to maxillary removable retainers. Volunteers were recruited to use four retainer types: conventional wrap-around (CWA), wrap-around with an anterior opening (OWA), "U" wrap-around (UWA), and clear thermoplastic retainer (CT). The main outcomes were the volunteers' perceptions, evaluated with a 100-mm visual analogue scale, and their preferred retainer. The retainers were used for 21 days each (washout intervals of 7 days). Nineteen volunteers (27 ± 4.53 years) were randomly divided into four groups that used the four retainers, but with a different sequence. Perceptions were evaluated immediately after the use of each retainer and the preference at the end of the research. Repeated measures ANOVA and Friedman tests with post-hoc Tukey's test (intergroup comparisons), and Pearson and Spearman analyses (correlations between perceptions) were applied. The WA retainers did not significantly differ among themselves. The CT was rated significantly worse in speech (p ≤ 0.001), discomfort (p < 0.001), and occlusal interference (p < 0.001), and did not significantly differ from the others in esthetics. Users preferred significant more the WA retainers in comparison with the CT retainers. The occlusal interference caused by the CT was positively correlated to other perceptions, such as changes in speech and discomfort. WA retainers presented similar preference and perceptions, but were significantly better than the CT. The CT occlusal coverage appeared to be the primary cause of its rejection.

Frictional evaluations of dental typodont models using four self-ligating designs and a conventional design.

Abstract: After a previous study using typodonts and three standardized archwire (AW) sizes, the frictional evaluations of four self-ligating brackets were directed toward the optimal AW-bracket system. Four participating manufacturers suggested three AWs, which were a representation of the three stages of orthodontic treatment, to be coupled with their respective self-ligating design. Four replicated typodont models were mounted with a self-ligating design, and a fifth model was mounted with a conventional design that served as a control. The first experiment evaluated the manufacturer-suggested AWs against the respective self-ligating design. Because no third-stage AWs could engage their respective designs, a second experiment was implemented to gain more detailed analyses of the designs. This experiment included any successful manufacturer-suggested AWs from the first experiment against the four self-ligating designs and the control design. All self-ligating designs performed with the efficiency and reproducibility associated with expectations. Specifically, self-ligation outperformed the conventional brackets when coupled with up to 0.020- x 0.020-inch wires. The clearance of the various AW sizes and alloys changed with malocclusion. Furthermore, the parameter that best correlated with drawing forces was the bending stiffness of the AW, which was directly associated with the nominal dimension of each wire. The best AW-bracket system can be selected, when taking into account the stiffness (elastic modulus and size of the AW) along with the amount of malocclusion present, once the treatment plan is determined.

Interdisciplinary index of prosthodontic/substitution orthodontic treatment need for patients with missing teeth.

The need for treatment in cases of missing teeth may result from aesthetic demands or functional impairment, although tooth loss itself does not necessarily constitute a need for prosthetic replacement. In selected cases, restorative treatment can be replaced by tooth autotransplantation or substitution orthodontic treatment. The authors have tried to make an index based not on missing particular teeth, but on the presence of spacing requiring restoration. An attempt has been made to categorize the restorative treatment need. Orthodontic treatment was considered, when it could completely eliminate the need for prosthetic treatment. The proposed classification could be used for assessing eligibility for public refund of restorative or substitution orthodontic treatment, as well as to motivate the patients to have restorations. It should be an individual approach-based decision, which treatment: orthodontic substitution tooth movement or prosthodontic is more cost-effective for the rest of the patient's life.

A closer look at General Dental Service orthodontics in England and Wales. II: What determines appliance selection?

AIM: To elucidate factors that influence choice of appliance type in General Dental Service (GDS) orthodontics in England and Wales. METHOD: Records were obtained for 1527 cases, representing a systematic 2 per cent sample of GDS cases completed during 1990-91. Evaluation involved Discriminant Analysis to find the most influential factors in appliance choice. Factors considered included patient and practitioner characteristics, and features of the malocclusion as assessed by Occlusal Indices. RESULTS: Full data were available for 1217 cases. 24 per cent of treatments included use of dual- and 26 per cent single-arch fixed appliances. Appliance choice was predictable in 55 per cent of cases. Older patients, orthodontically qualified practitioners, high Peer Assessment Rating score at start, permanent dentition, lower grades of the Dental Health Component of the Index of Orthodontic Treatment Need at start, and practitioners with high gross earnings from orthodontics, all tended to be associated with more frequent use of fixed appliances. CONCLUSIONS: Possession of a diploma or membership in orthodontics was associated with more frequent use of both dual- and single-arch fixed appliances. Better appliance selection, and thus more effective treatments in the GDS, may result from a greater availability of practitioners with formal postgraduate training in orthodontics.

Effects and adverse events of a dental appliance for treatment of obstructive sleep apnoea.

In a prospective study, 95 patients with mild to moderate obstructive sleep apnoea (OSA) were randomised to receive either surgical treatment, uvulopalatopharyngoplasty, (4-6 patients) or treatment with a nocturnal dental appliance for mandibular advancement (49 patients). Of the 49 dental appliance patients, 37 completed the 12-month follow-up. The aim of this study was to evaluate the effects and adverse events of dental appliance treatment from a one-year perspective. Somnography was employed to measure treatment effects before and 12 months post-treatment. At the 12-month control, somnography was performed twice: the first time with the dental appliance and the second time without it. Adverse events were recorded 2 weeks and 3, 6, and 12 months after treatment was initiated. The patients used the dental appliance on average 6 nights/week. After 12 months of treatment, the apnoea, apnoea/hypopnoea, oxygen desaturation, and snoring indices decreased significantly. Ninety-five per cent of the patients reduced their apnoea index by > or = 50% and 78% of the patients were normalised following treatment. At the somnographic registration without the dental appliance, the values were found comparable to what they were before treatment. Mandibular mobility and occlusion were constant throughout the study. The adverse events resulting from using the dental appliance were relatively minor and infrequent, and no serious complications were observed except for two patients who reported pain from the temporomandibular joint. In conclusion, the dental appliance has been shown to be a valuable treatment method for mild to moderate OSA with few adverse events in the stomatognathic system or other complications.

Biomechanical investigation of the hybrid retraction spring.

We succeeded in developing a retraction spring that shows virtually constant retracting forces up to an activation of about 4.5 mm through the use of various non-linear materials. Compared to all other known retraction springs, an actual bodily retraction is possible over a large range for the first time. The clinical application requires no more than one reactivation. The anti-tipping moment is 10 Nmm and is to be considered constant over the entire activation range. This anti-tipping moment produces an extrusive force for the canine and an intrusive force for the molar. This side-effect can be avoided by bending a sweep into the steel portion or compensated by bending a step into the steel portion of this retraction spring. The anti-rotational moment is about 3 to 5 Nmm measured over the entire activation range. In contrast to many other springs, the favorable M/F ratio for the anti-tipping movement allows an actual bodily retraction of canines. Even when the retracting force is no longer active, the moment that moves the root of the canine distally is still acting, so that the spring can also be used for the root movement. The M/F ratio for the anti-rotational movement is between 3 and 5 mm and therefore allows retraction of the canine without causing major distortions. Customary brackets with a .018" or .022" horizontal slot can be used, as the spring is designed for a .018" x .018" vertical slot. Each spring can be used for both the left and the right canines. The steel portion allows second-order and, if desired, third-order bends to be made. The additionally necessary bends have already been described. The hybrid retraction spring can also be applied for en masse retraction of incisors if a cross-tube is used for the anterior area.

Torque transmission between square wire and bracket as a function of measurement, form and hardness parameters.

The aim of the study was to investigate the influence of cross section, edge geometry and structural hardness on torque transmission between square wire and bracket. For this purpose, 5 different brands of stainless steel square wire in 3 dimensions (0.016" x 0.016", 0.016" x 0.022" and 0.017" x 0.025") were inserted into edgewise brackets with a slot size of 0.018" and loaded with different torques (1 and 3 Ncm). The slot and wire geometries were analyzed by computer on ground specimens before and after loading. In addition, the Vickers hardness and micro-hardness of the unstressed and stressed metal surfaces were determined. While the slot size was very accurately maintained, the wire dimensions deviated downwards by an average of 10%. Torque transmission led to notching and bending-up phenomena on the bracket slot flanks. A torque loading of 3 Ncm increased the torque play of 0.016" x 0.022" wires by 3.6 degrees, and of 0.017" x 0.025" wires by 3.7 degrees. In the case of 0.016" x 0.016" wires, an effective torque transmission was no longer possible. The average Vickers hardness of the wires was 533 kp/mm2, and that of the brackets 145 kp/mm2. The micro-hardness in the deformation area of stressed internal slot walls increased with increasing load transmission from 204 to 338 kp/mm2. As a result of excessively small wire dimensions and plastic deformation of the brackets, a relatively large torque play occurs. Deformation and notching in the area of the internal slot walls are inconsistent with demands for recycling brackets. A standardization of bracket wire systems stating the actual torque play would be desirable.

Bending and torquing accuracy of the bending art system (BAS).

With the bending art system (BAS) the computerized production of individual arch wires has become possible. The BAS consists of an intraoral camera, a computer program and a bending machine producing the archwire by consecutive bending and twisting procedures. This study examines the accuracy of the bending machine when using 0.016" x 0.016" and 0.016" x 0.022" steel wire of rectangular cross-section. Bending angles ranging from 6 degrees to 54 degrees, and torsion angles ranging from 2 degrees to 35 degrees were tested; also the minimum distance between these individual operations was determined. The bent pieces of wire were analysed in a 3D-coordinate gauging system. The 0.016" x 0.016" steel wire showed a mean measuring error of 0.62 degree in bending procedures and of 0.72 degree in torsion procedures, whereas the 0.016" x 0.022" steel wire showed an error of 0.87 degree with edgewise bendings and of 0.86 degree with torsions. To ensure this accuracy a minimum distance of 0.5 mm to 0.7 mm, depending on which kind of bending combination is used, between bending and torsion is required. The error could be reduced even further if a more constant wire material and a more accurate calibration of the bending machine were used. All in all the precision of the bending machine meets the clinical requirements.

Effectiveness of intra- and extraoral aids to the bionator. A controlled study within the scope of the "Wuerzburg concept".

A bimaxillary device is effective only if the therapeutic position of the mandible is maintained for as long a period as possible by day and night, i.e. the lower jaw cannot "drop" from the construction bite position. One simple means of preventing the mandible from dropping out of the bimaxillary appliance during sleep and thus of ensuring adaptation of the muscles and of the joint structures during the night without impairing active adaptation during daytime functions (speaking, swallowing) is being used at Wuerzburg University Department of Orthodontics: In connection with anterior traction, which anchors the bimaxillary appliance to the maxilla, attachments are fixed to the mandibular canines or first premolars, so that the mandible is kept in the therapeutic position during the night by means of elastics. Besides the description of this method, the results of a clinical study on its effectiveness are presented in this paper. In the experimental group (20 Class II/1 patients) treated with the combination of bionator with anterior extraoral traction and up-and-down elastics, the increase of the SNB angle and accordingly of the ANB angle was twice as great as in a control group treated only with bionator and extraoral traction without additional securing of the mandible.