An Evaluation of the Accuracy and Precision of Ceramic Orthodontic Bracket Slot Dimensions Utilizing Micro-Computed Tomography (Micro-CT).

This study's aim is to determine the accuracy and precision of the bracket slot height in MBT 0.022″ ceramic brackets. Five brackets from 11 different systems (n = 55) were scanned using micro-computed tomography (micro-CT). The slot height was measured at the face (external) and base (internal) of the slot. Data were analyzed using a One-Sample t-Test, and a Paired t-Test. The lowest external height was seen in OrthoCare Purity® at 0.02264″ (2.9%), and the greatest in TOC Ghost Advanced® at 0.02736″ (24.4%). The lowest internal height was seen in Forestadent Glam® at 0.02020″ (-8.2%), and the greatest in TOC Ghost Advanced® at 0.2547″ (15.8%). OrthoCare Purity® measurements corresponded most closely with the expected measurements. TP InVu® was found to be the most precise bracket for external height (range = 0.00043″) and American Orthodontics 20/40® for internal height (range = 0.00028″). In assessing slot geometry, all brackets demonstrated a higher mean external slot height compared to the internal measurements at the base of the bracket. Orthodontic bracket slots are larger than expected and slot parallelism was not observed in any bracket brand tested. Similarly, slot dimensions are imprecise where two 'identical' brackets have different slot sizes. The clinician should, therefore, assume that play is most likely higher than expected.

The impact of satisfaction, and autonomous learning strategies use on scholastic achievement during Covid-19 confinement in Malaysia.

The purpose of this study is twofold. Firstly, this study seeks to better understand students' learning experience, through scholastic achievement and secondly, this study analyses students' use of autonomous learning strategies, namely satisfaction, self-efficacy, social interactive engagement and study engagement in digital learning amidst the Covid-19 lockdown. While Malaysia grapples with a growing number of Covid-19 cases, the underlying toll of the pandemic has hit the youth hard with many mental health concerns and this has affected their learning. The nurturing of autonomous learning strategies especially during the Covid-19 confinement is critically needed to assist this vulnerable group. Although there is a plethora of studies given students' use of autonomous learning strategies towards scholastic achievement during the Covid-19 lockdown internationally, studies in the Asia region are still rudimentary. This study investigated 316 university students from targeted universities in Malaysia. Responses were gathered from an online survey. Data were analysed using Partial Least Squares-Structural Equation Modelling (PLS-SEM), a second-generation multivariate statistical approach to assess the outer model and inner model that displays the relationships between the constructs. The results of this case study reported that student interactive engagement (ß = 0.348, t = 5.45) and study environment (ß = 0.314, t = 4.81) have a significant impact on students' scholastic achievement during the lockdown. Remarkably, new insights are uncovered in this paper revealing no relationship between self-efficacy and satisfaction with students' scholastic achievement. Possible explanations surrounding why satisfaction and self-efficacy were suppressed by the lockdown are discussed. The outcomes of this study provide key insights that may assist students to condition their minds to use autonomous learning strategies in digital learning to enhance their scholastic achievement.

A four-year review of orthodontic cases appearing before the General Dental Council Professional Conduct Committee.

OBJECTIVES: To evaluate the characteristics of orthodontic cases at the General Dental Council's (GDC) Professional Conduct Committee (PCC). DESIGN: Review of data from the GDC website for orthodontically related hearings or those involving orthodontic treatment providers during 2015-2018. SETTING: Observational descriptive study. METHODS: Data were accessed from the GDC website by a single researcher to retrieve orthodontic cases. The press office of the GDC was contacted to ensure all data were captured. For each case that met the inclusion criteria, demographic details of the registrant, the charges proved/not proved and final outcome of the case were recorded. RESULTS: A total of 23 registrant cases involved orthodontics and this was 8% of the total number of PCC hearings during 2015-2018. Nine (39%) of the registrants had a Membership in Orthodontics qualification although only 7 (30%) were registered as orthodontists on the UK GDC Specialist List in Orthodontics. Charges related to clinical assessment, consent and record keeping were mostly proved for dentists (13/16 hearings for each) whereas a poor standard of treatment and not cooperating with the GDC were mostly proved for orthodontists (4/7 hearings for each). Overall, conditions were imposed in 10 (44%) cases, erasure in 7 (30%) cases, suspension in 5 (22%) cases and a reprimand in 1 (4%) case. CONCLUSION: The GDC continue to view misdemeanours seriously and it would be prudent for registrants to be familiar with the nature of these hearings to reduce the risk of finding themselves in such a predicament.

External proficiency testing improves inter-scorer reliability of polysomnography scoring.

PURPOSE: This study evaluated whether or not polysomnography (PSG) inter-scorer reliability (ISR) across sleep centres could be improved by external proficiency testing (EPT), or by EPT combined with method alignment training. METHODS: Experienced scorers form 15 sleep centres were randomised to the following: (1) a control group, (2) a group that received a self-directed intervention of EPT reports (EPTPassive) or (3) a group that received an active intervention of method alignment training and EPT reports (EPTActive). Respiratory, arousal and sleep scoring ISR from sixteen PSG fragments were compared between groups across time. RESULTS: Among 30 scorers, there were no ISR changes in controls between baseline (BL) and 6 months (6 m). Both EPT groups showed ISR improvement from BL to 6 m for respiratory, arousal and sleep scoring (p < 0.05). Respiratory scoring back-transformed mean (95CI) proportion of specific agreement (PSA) for the EPTPassive group improved from 0.78 (0.72-0.84) to 0.80 (0.74-0.86) and for the EPTActive group from 0.80 (0.74-0.85) to 0.82 (0.76-0.88). Arousal scoring PSA for the EPTPassive group improved from 0.72 (0.66-0.77) to 0.74 (0.69-0.79) and for the EPTActive group from 0.71 (0.65-0.76) to 0.77 (0.72-0.82). Sleep scoring kappa for the EPTPassive group improved from 0.64 (0.58-0.69) to 0.73 (0.68-0.77) and for the EPTActive group from = 0.75 (0.71-0.80) to 0.80 (0.76-0.85). Overall, poorer performers achieved greater improvement. CONCLUSION: External proficiency testing produced modest, statistically significant PSG inter-scorer reliability improvements among experienced scorers across sleep centres, with potential to improve clinical management of individual patients and increase research study statistical power.

What are dental professionals posting on Facebook? A cross-sectional content analysis.

OBJECTIVE: To profile the posts on open orthodontic Facebook groups and identify which communication strategies and media modalities generate the most engagement from users. DESIGN: A cross-sectional content analysis. SETTING: Facebook Internet-based search. METHODS: Post data were collected over a one-month period from the 10 largest public orthodontic Facebook groups. Evaluation of group characteristics included membership levels, number of administrators, time each group had been in existence and growth rate of each group. The number of posts, the numbers and types of engagement (likes, emojis, comments, shares) and engagement rate were calculated. The communication strategies (e.g. case presentation, course promotion, etc.) and media modalities (e.g. plain text, photograph, etc.) were recorded. RESULTS: The study identified 190,268 Facebook members from the 10 largest orthodontic Facebook groups (median 17,811; interquartile range [IQR] 11,977). The median time the groups had existed was six years (median 2175 days; IQR 2311 days) and the median number of new group members in the past month was 1257 (IQR 2773). The median number of new group members in the past month was 1257 (IQR 2773). There were 227 postings during the study period with 2546 engagements. The overall median number of engagements was 196 (IQR 445) and the engagement rate of posts was 1.3% overall. Posts relating to course promotion (n = 63, 28%) followed by product promotion (n = 42, 19%) were the most common. Case presentation style posts accounted for 15% (n = 35). The level of engagement was greater for posts that had a clinical component compared to posts that did not (P < 0.001). For media modality, posts that included a photograph had greater engagement (P < 0.001). CONCLUSION: There are frequent posts on course and product promotion in orthodontic Facebook groups; however, these are associated with low levels of engagement. Posts that are clinically orientated and include photographs have higher levels of engagement.

Canine avulsion: An extreme complication of a fixed mandibular lingual retainer / Extraction d'une canine : une complication extrême d'une contention mandibulaire linguale fixe

Introduction: The use of fixed retainers at the end of a course of orthodontic treatment has become standard practice. The main complication that can occur with fixed retainers is the detachment of the wire from one or more teeth. A less common complication is unwanted tooth movement. Method: This article presents a patient with extreme tooth movement associated with a mandibular fixed retainer. Ten years after orthodontic treatment, a 26-year-old male sought treatment for post-orthodontic movement of the mandibular anterior six teeth. Despite the fixed retainer still being attached to all teeth, the apex of the right canine was completed avulsed labially. Severe labial recession was also present on the left lateral incisor. The canine was extracted, and the fixed retainer was removed. Significant root resorption identified on a panoramic radiograph contraindicated any further extensive orthodontic intervention. Discussion: This case highlights that clinicians and patients should be aware of this rare but serious complication.

Introduction: L'utilisation d'un appareil de contention fixe à la fin d'un traitement d'orthodontie est devenue une pratique courante. La principale complication qui peut survenir avec les contentions fixes est le décollement du fil sur une ou plusieurs dents. Le mouvement dentaire indésirable est une complication moins courante. Méthode: Cet article est illustré par le cas d'un patient présentant un mouvement dentaire extrême associé à une contention mandibulaire fixe. Dix ans après un traitement d'orthodontie, un homme de 26 ans a demandé un traitement en raison d'un mouvement post-orthodontique des six dents antérieures mandibulaires. Bien que le dispositif de contention fixe soit toujours en place sur toutes les dents, l'apex de la canine droite a été complètement versé vestibulairement. Une récession gingivale vestibulaire sévère était également présente sur l'incisive latérale gauche. La canine a été extraite et la contention fixe a été retirée. Une résorption radiculaire importante identifiée sur une radiographie panoramique contre-indiquait toute nouvelle intervention orthodontique. Discussion: Ce cas souligne que les cliniciens et les patients doivent être conscients de cette complication rare mais grave.

Canine avulsion: An extreme complication of a fixed mandibular lingual retainer.

The use of fixed retainers at the end of a course of orthodontic treatment has become standard practice. The main complication that can occur with fixed retainers is the detachment of the wire from one or more teeth. A less common complication is unwanted tooth movement. This article presents a patient with extreme tooth movement associated with a mandibular fixed retainer. Ten years after orthodontic treatment, a 26-year-old male sought treatment for post-orthodontic movement of the mandibular anterior 6 teeth. Despite the fixed retainer still being attached to all teeth, the apex of the right canine was completed avulsed labially. Severe labial recession was also present on the left lateral incisor. The canine was extracted, and the fixed retainer was removed. Significant root resorption identified on a panoramic radiograph contraindicated any further extensive orthodontic intervention. This case highlights that clinicians and patients should be aware of this rare but serious complication.

Dental Attendance and Self-reported Oral Health Status of Renal Dialysis Patients: A Comparison of Results with the UK Adult Dental Health Survey.

PURPOSE: To compare the oral health status of renal patients attending a dialysis unit at a London teaching hospital with an age- and sex-matched sample from the Adult Dental Health Survey UK (ADHS) 2009. MATERIALS AND METHODS: Questions adapted from the ADHS 2009 national survey were used to interview renal dialysis patients about their oral health, oral hygiene and dental visits. Any significant differences between the two groups were statistically analysed using the chi-squared (χ2) test. RESULTS: Two hundred renal dialysis patients participated. More renal dialysis patients were edentulous (p < 0.0001) and those who were dentate had fewer teeth (p < 0.0001) compared to the ADHS 2009 participants. Although 12% of the renal dialysis patients had difficulty in finding a dentist, 77% were linked to a dental practice, but fewer reported that they had previously been shown how to brush their teeth compared to the dentate ADHS group (p < 0.0001). The frequency of brushing (twice daily) was similar in the dialysis and ADHS groups. CONCLUSION: Awareness for good oral health needs to be raised in this group of medically compromised patients regularly attending a hospital unit. The responsibility for achieving this goal needs to be shared by both dialysis teams and oral health care professionals. We suggest an 'oral health toolkit' be made available in dialysis units for both professionals and patients.

Smartphones and dental trauma: the current availability of apps for managing traumatic dental injuries.

BACKGROUND/AIM: There is a general consensus regarding the lack of awareness regarding the emergency management of traumatic dental injuries amongst laypersons and dental professionals. This article aims to provide an overview of the apps available for traumatic dental injuries using smartphones. These apps may serve as a gateway for raising awareness of traumatic dental injuries. MATERIALS AND METHOD: Three smartphone devices were used to access their respective app stores (Nokia Lumia 635 with Windows Phone OS 8.1; iPhone 5 with iOS 8.1; Samsung Galaxy Ace II with Android OS v2.3.6 Gingerbread). Nine phrases were searched: broken tooth/teeth; chipped tooth/teeth; dental emergency; dental injury; dental trauma; fractured tooth/teeth; knocked-out tooth/teeth; tooth/teeth injury; and tooth/teeth trauma. RESULTS: Seven apps for the Android and one app for the Apple operating system were relevant. The only Apple iOS app retrieved (Dental Trauma) was also found for the Android OS (Dental Trauma First Aid) and had the endorsement of the International Association of Dental Traumatology. AcciDent was the only app dedicated to traumatic dental injuries targeted solely towards dental professionals. Five other apps (Chipped Tooth Solution, Dental Crown Repair, Fixing Cracked Tooth, Repairing the Front Tooth and Solution to Broken Tooth) appeared to come from the same source (KBES). No traumatic dental injury apps were found for the Windows Phone OS. CONCLUSION: There are apps available for both patients and dentists that range in quality and on the whole lack real-life photographs. Future apps should continue to provide good quality, evidence-based and validated material.

Dental Trauma Part 1- Acute Management of Luxation/Displacement Injuries.

Fortunately, traumatic dental injuries are a relatively uncommon occurrence in general dental practice. However, when they do present, timely diagnosis and treatment of such injuries is essential to maximize the chance of a successful outcome. This is the first part of a two-part series on traumatic dental injuries that are commonly encountered in the clinical setting. Part one will cover acute management of luxation/displacement injuries that primarily affect the supporting structures of the tooth, while part two will cover the management of fracture injuries associated with teeth and the alveolar bone. Clinical relevance: A simple, step-by-step approach in the diagnosis and clinical management of acute luxation/displacement injuries should be part of a dental clinician's knowledge.

Dental Trauma 2- Acute Management of Fracture Injuries.

Fortunately, traumatic dental injuries are a relatively uncommon occurrence in general dental practice. However, when they do present, timely diagnosis and treatment of such injuries is essential to maximize the chance of a successful outcome. This is the second part of a two-part series on traumatic dental injuries that are commonly encountered in the clinical setting. Part one covered the management of acute luxation/displacement injuries affecting the supporting structures of the tooth, while part two will cover the management of fracture injuries associated with teeth and the alveolar bone. Clinical relevance: Traumatic dental injuries are uncommon occurrences in everyday general dental practice. This article aims to provide a simple, step-by-step approach in the diagnosis and clinical management of acute fracture injuries.

Removable cast chrome cobalt retainers for extended or indefinite period clinical use.

Patients are frequently being asked to wear orthodontic retainers for as long as they want their teeth to remain in the post-treatment position. Fixed retainers, which are placed on the lingual surface of anterior teeth only, have the advantage of minimal compliance issues but are not without their problems related to wire fracture, adhesive failure and potential gingival or periodontal disease. Plastic retainers, although associated with relatively good aesthetics and compliance, have limitations related to their physical and mechanical properties. This paper describes a chrome cobalt metal retainer that could be used as a long-term retainer with few drawbacks. The properties of chrome cobalt are described and the clinical procedure is outlined.

Orthodontic apps for smartphones.

BACKGROUND: The increasing use of technology is rapidly changing our personal and professional lives. Smartphones allow users to access information in ways previously not possible and our patients may be accessing apps to source information about orthodontics and help them through their treatment. AIM: To provide an overview of the orthodontic apps currently available on four of the main operating systems with emphasis on those apps targeted towards new and existing orthodontic patients as well as practising clinicians. METHOD: Four mobile devices were used to search four mobile operating systems (Android, Apple, Blackberry and Windows) using the key words 'braces', 'orthodontist', 'orthodontic' and 'orthodontics'. RESULTS: Android and Apple operating systems derived all of the apps considered relevant to orthodontic clinicians and patients. Clinician apps (11) related to orthodontic meetings (3), publications (3), products (3) and tooth ratio calculators such as Bolton (2). Patient apps (8) related to reminding patients about elastic wear (2) and aligner wear (2), dealing with orthodontic emergencies (2), orthodontic products (1) and a progress tracker of treatment (1). CONCLUSIONS: Apps are available for both orthodontic clinicians and patients; however, much of the information contained within them is often not independent and even more often not validated. Patients are increasingly likely to access apps and clinicians should direct patients to those that are most appropriate and useful.

An ectopic tooth concealing an odontogenic myxoma.

UNLABELLED: This case report presents a 13-year-old girl who attended an orthodontic clinic for an ectopic UR5. After investigation, a diagnosis of an odontogenic myxoma was made and the tumour was excised. A panoramic radiograph taken almost two years earlier for another dental problem was found to show an ectopic UR5 associated with a subtle radiolucency. Odontogenic myxomas may be of higher frequency than once thought in the paediatric population and therefore should always be considered in the differential diagnosis of any intraosseous radiolucency. Any radiolucent area associated with an unerupted tooth should be investigated further or closely followed up. CLINICAL RELEVANCE: The odontogenic myxoma is a rare but potentially serious benign tumour of the jaws.

Ozone exposure during the early postnatal period alters the timing and pattern of alveolar growth and development in nonhuman primates.

Exposure to oxidant air pollutants in early childhood, with ozone as the key oxidant, has been linked to significant decrements in pulmonary function in young adults and exacerbation of airway remodeling in asthma. Development of lung parenchyma in rhesus monkeys is rapid during the first 2 years of life (comparable to the first 6 years in humans). Our hypothesis is that ozone inhalation during infancy alters alveolar morphogenesis. We exposed infant rhesus monkeys biweekly to 5, 8 hr/day, cycles of 0.5 ppm ozone with or without house dust mite allergen from 1 to 3 or 1 to 6 months of age. Monkeys were necropsied at 3 and 6 months of age. A morphometric approach was used to quantify changes in alveolar volume and number, the distribution of alveolar size, and capillary surface density per alveolar septa. Quantitative real time PCR was used to measure the relative difference in gene expression over time. Monkeys exposed to ozone alone or ozone combined with allergen had statistically larger alveoli that were less in number at 3 months of age. Alveolar capillary surface density was also decreased in the ozone exposed groups at 3 months of age. At 6 months of age, the alveolar number was similar between treatment groups and was associated with a significant rise in alveolar number from 3 to 6 months of age in the ozone exposed groups. This increase in alveolar number was not associated with any significant increase in microvascular growth as measured by morphometry or changes in angiogenic gene expression. Inhalation of ozone during infancy alters the appearance and timing of alveolar growth and maturation. Understanding the mechanism involved with this altered alveolar growth may provide insight into the parenchymal injury and repair process that is involved with chronic lung diseases such as severe asthma and COPD.

AASM criteria for scoring respiratory events: interaction between apnea sensor and hypopnea definition.

STUDY OBJECTIVES: To examine the impact of using a nasal pressure sensor only vs the American Academy of Sleep Medicine (AASM) recommended combination of thermal and nasal pressure sensors on (1) the apnea index (AI), (2) the apnea-hypopnea index (AHI), where the AHI is calculated using both AASM definitions of hypopnea, and (3) the accuracy of a diagnosis of obstructive sleep apnea (OSA). DESIGN: Retrospective review of previously scored in-laboratory polysomnography. SETTING: A tertiary-hospital clinical sleep laboratory. PATIENTS OR PARTICIPANTS: One hundred sixty-four consecutive adult patients with a potential diagnosis of OSA, who were examined during a 3-month period. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Studies were scored with and without the use of the oronasal thermal sensor. AIs and AHIs, using the nasal pressure sensor alone (AI(np) and AHI(np)), were compared with those using both a thermal sensor for the detection of apnea and a nasal pressure transducer for the detection of hypopnea (AI(th) and AHI(th)). Comparisons were repeated using the AASM recommended (AASM(rec)) and alternative (AASM(alt)) hypopnea definitions. AI was significantly different when measured from the different sensors, with AI(np) being 51% higher on average. Using the AASM(rec) hypopnea definition, the mean AHI(np) was 15% larger than the AHI(th); with large interindividual differences and an estimated 9.8% of patients having a false-positive OSA diagnosis at a cutpoint of 15 events and 4.3% at 30 events per hour. Using AASM(alt) hypopnea definition, the mean AHI(np) was 3% larger than the AHI(th), with estimated false-positive rates of 4.6% and 2.4%, respectively. The false-negative rate was negligible at 0.1% for both hypopnea definitions. CONCLUSIONS: This study demonstrates that using only a nasal pressure sensor for the detection of apnea resulted in higher values of AI and AHI than when the AASM recommended thermal sensor was added to detect apnea. When the AASM(alt) hypopnea definition was used, the differences in AHI and subsequent OSA diagnosis were small and less than when the AASM(rec) hypopnea definition was used. In situations in which a thermal sensor cannot be used, for example, in limited-channel diagnostic devices, the AHI obtained with a nasal pressure sensor alone differs less from the AHI obtained from a polysomnogram that includes a thermal sensor when the AASM(alt) definition rather than the AASM(rec) definition of hypopnea is used. Thus, diagnostic accuracy is impacted both by the absence of the thermal sensor and by the rules used to analyze the polysomnography. Furthermore, where the thermal sensor is unreliable for sections of a study, it is likely that use of the nasal pressure signal to detect apnea will have modest impact.

Lingual orthodontics: an overview.

UNLABELLED: As adults increasingly seek orthodontic treatment, a growth has been witnessed in the demand for aesthetic orthodontics, the ultimate of which are appliances bonded to the lingual surfaces of the teeth. Development has spanned 30 years and many of the initial challenges faced with this approach have now been overcome. An overview is provided on the development of lingual appliances from conception through to the current systems available. Lingual orthodontics is not for every patient seeking treatment and therefore the indications and contra-indications are discussed, together with the advantages and disadvantages of this increasingly popular approach. CLINICAL RELEVANCE: Patients are increasingly asking dental professional about lingual appliances.

The 2007 AASM recommendations for EEG electrode placement in polysomnography: impact on sleep and cortical arousal scoring.

STUDY OBJECTIVE: To examine the impact of using American Academy of Sleep Medicine (AASM) recommended EEG derivations (F4/M1, C4/M1, O2/M1) vs. a single derivation (C4/M1) in polysomnography (PSG) on the measurement of sleep and cortical arousals, including inter- and intra-observer variability. DESIGN: Prospective, non-blinded, randomized comparison. SETTING: Three Australian tertiary-care hospital clinical sleep laboratories. PATIENTS OR PARTICIPANTS: 30 PSGs from consecutive patients investigated for obstructive sleep apnea (OSA) during December 2007 and January 2008. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: To examine the impact of EEG derivations on PSG summary statistics, 3 scorers from different Australian clinical sleep laboratories each scored separate sets of 10 PSGs twice, once using 3 EEG derivations and once using 1 EEG derivation. To examine the impact on inter- and intra-scorer reliability, all 3 scorers scored a subset of 10 PSGs 4 times, twice using each method. All PSGs were de-identified and scored in random order according to the 2007 AASM Manual for the Scoring of Sleep and Associated Events. Using 3 referential EEG derivations during PSG, as recommended in the AASM manual, instead of a single central EEG derivation, as originally suggested by Rechtschaffen and Kales (1968), resulted in a mean ± SE decrease in N1 sleep of 9.6 ± 3.9 min (P = 0.018) and an increase in N3 sleep of 10.6 ± 2.8 min (P = 0.001). No significant differences were observed for any other sleep or arousal scoring summary statistics; nor were any differences observed in inter-scorer or intra-scorer reliability for scoring sleep or cortical arousals. CONCLUSION: This study provides information for those changing practice to comply with the 2007 AASM recommendations for EEG placement in PSG, for those using portable devices that are unable to comply with the recommendations due to limited channel options, and for the development of future standards for PSG scoring and recording. As the use of multiple EEG derivations only led to small changes in the distribution of derived sleep stages and no significant differences in scoring reliability, this study calls into question the need to use multiple EEG derivations in clinical PSG as suggested in the AASM manual.

A comparison of cephalometric measurements: a picture archiving and communication system versus the hand-tracing method--a preliminary study.

Traditionally, cephalometric analysis has been carried out using a hand-tracing manual method. In imaging, picture archiving and communication systems (PACS) are information management systems used for the capture and measurement of medical and dental radiographs. Although not customized for lateral cephalometry, this study aimed to evaluate the cephalometric measurements made on screen using PACS compared with the conventional hand-tracing method. Six angular and four liner parameters were measured on five radiographs of four females and one male with an age range of 14-20 years. Analysis was completed using the Wilcoxon rank-sum test. For the electronic method, SNB (P=0.04) and lower incisor angle (P=0.05) were the only parameters found to be significantly different between the two operators. There was no significant difference between operators 1 and 2 for the hand-tracing method for any measurement. All measurements were comparable between the two methods. This preliminary study would suggest that using PACS may be an acceptable method for obtaining cephalometric measurements for treatment planning; however, further evaluation is necessary with a larger sample size.

Nance palatal arch: a cautionary tale.

The Nance palatal arch is considered a useful means of maintaining arch length and reinforcing anchorage control in the orthodontic patient. Difficulty with oral hygiene around the Nance arch and inflammation and bunching of the gingivae under the acrylic fitting surface are common problems associated with this appliance. We present a case of alveolar bone loss and gingival recession around the palatal root surfaces of the upper incisor teeth following use of Nance palatal arch. A possible cause for this is explored and management of the patient after the Nance arch was removed is discussed.