Telomerase mRNA Enhances Human Skin Engraftment for Wound Healing.

Deep skin wounds represent a serious condition and frequently require split-thickness skin grafts (STSG) to heal. The application of autologous human-skin-cell-suspension (hSCS) requires less donor skin than STSG without compromising the healing capacity. Impaired function and replicative ability of senescent cutaneous cells in the aging skin affects healing with autologous hSCS. Major determinants of senescence are telomere erosion and DNA damage. Human telomerase reverse transcriptase (hTERT) adds telomeric repeats to the DNA and can protect against DNA damage. Herein, hTERT mRNA lipid nanoparticles (LNP) are proposed and evaluated for enhancing cellular engraftment and proliferation of hSCS. Transfection with optimized hTERT mRNA LNP system enables delivery and expression of mRNA in vitro in keratinocytes, fibroblasts, and in hSCS prepared from donors' skin. Telomerase activity in hSCS is significantly increased. hTERT mRNA LNP enhance the generation of a partial-thickness human skin equivalent in the mouse model, increasing hSCS engraftment (Lamin) and proliferation (Ki67), while reducing cellular senescence (p21) and DNA damage (53BP1).

Cost-Effectiveness of the Use of Autologous Cell Harvesting Device Compared to Standard of Care for Treatment of Severe Burns in the United States.

INTRODUCTION: When introducing a new intervention into burn care, it is important to consider both clinical and economic impacts, as the financial burden of burns in the USA is significant. This study utilizes a health economic modeling approach to estimate cost-effectiveness and burn center budget-impact for the use of the RECELL® Autologous Cell Harvesting Device to prepare autologous skin cell suspension (ASCS) compared to standard of care (SOC) split-thickness skin graft (STSG) for the treatment of severe burn injuries requiring surgical intervention for definitive closure. METHODS: A hospital-perspective model using sequential decision trees depicts the acute burn care pathway (wound assessment, debridement/excision, temporary coverage, definitive closure) and predicts the relative differences between use of ASCS compared to SOC. Clinical inputs and ASCS impact on length of stay (LOS) were derived from clinical trials and real-world use data, American Burn Association National Burn Repository database analyses, and burn surgeon interviews. Hospital resource use and unit costs were derived from three US burn centers. A budget impact calculation leverages Monte Carlo simulation to estimate the overall impact to a burn center. RESULTS: ASCS treatment is cost-saving or cost-neutral (< 2% difference) and results in lower LOS compared to SOC across expected patient profiles and scenarios. In aggregate, ASCS treatment saves a burn center 14-17.3% annually. Results are sensitive to, but remain robust across, changing assumptions for relative impact of ASCS use on LOS, procedure time, and number of procedures. CONCLUSIONS: Use of ASCS compared to SOC reduces hospital costs and LOS of severe burns in the USA. FUNDING: AVITA Medical.

Enhanced hearing in noise for cochlear implant recipients: clinical trial results for a commercially available speech-enhancement strategy.

OBJECTIVE: To demonstrate benefits for speech perception and everyday listening in quiet and in noise with a speech-enhancement strategy called ClearVoice, which was designed to improve listening in complex acoustic environments without compromising hearing in quiet. STUDY DESIGN: A 2-week randomized crossover design was used to evaluate ClearVoice in 46 adults unilaterally implanted with a CII/HiRes 90K cochlear implant who had at least 6 months experience with HiRes Fidelity 120 sound processing. Speech perception was assessed using the AzBio sentences presented in quiet, in speech-spectrum noise and in multitalker babble. Subjective listening benefit and strategy preference were assessed with a questionnaire. ClearVoice has 3 gain settings (low, medium, and high), each intended as a full-time listening option according to individual preference. Speech understanding after acute use of ClearVoice-low was compared with HiRes Fidelity 120 during an initial test session. Speech perception abilities were compared with HiRes Fidelity 120 after 2 weeks of exclusive use of ClearVoice-medium, and after 2 weeks of exclusive use of ClearVoice-high. During a fifth week, participants were fit with 3 programs for comparison (HiRes Fidelity 120, ClearVoice-medium, and ClearVoice-high), after which, they reported preference and everyday listening benefits via a questionnaire. RESULTS: ClearVoice significantly improved speech understanding in speech-spectrum noise and multitalker babble, did not compromise listening in quiet, was preferred for everyday listening, and provided improved hearing in real-life situations. CONCLUSION: ClearVoice improves hearing in noise for cochlear implant recipients who use HiRes Fidelity 120 sound processing.

A comparison of space closure rates between preactivated nickel-titanium and titanium-molybdenum alloy T-loops: a randomized controlled clinical trial.

The purpose of this study was to conduct a prospective randomized controlled clinical trial to evaluate the rate of space closure and tooth angulation during maxillary canine retraction using preactivated T-loops made from titanium-molybdenum alloy (TMA) and nickel-titanium (NiTi). Twelve patients (six males and six females) aged between 13 and 20 years who had upper premolar extractions were included, and each acted as their own control, with a NiTi T-loop allocated to one quadrant and TMA to the other using a split mouth block randomization design. The loops were activated 3 mm at each visit to deliver a load of approximately 150 g to the upper canine teeth. Maxillary dental casts, taken at the first and each subsequent monthly visit, were used to evaluate changes in extraction space and canine angulation. All used T-loops were compared with unused loops in order to assess distortion. Mixed model statistical analysis was used to adjust for confounding variables. The mean rate of canine retraction using preactivated NiTi and TMA T-loops was 0.91 mm/month (±0.46) and 0.87 mm/month (±0.34), respectively. The canine tipping rates were 0.71 degrees/month (±2.34) for NiTi and 1.15 degrees/month (±2.86) for TMA. Both the rate of space closure and the tipping were not significantly different between the two wire types. The average percentage distortion of the TMA T-loop was 10 times greater than that of the NiTi loops when all other variables were matched. There was no difference in the rate of space closure or tooth angulation between preactivated TMA or NiTi T-loops when used to retract upper canines. The NiTi loops possessed a greater ability to retain and return to their original shapes following cyclical activation.

Orthodontic education programs: an international comparison of students' views and experiences.

INTRODUCTION: The purpose of this study was to identify the demographic characteristics of students completing certificate programs in orthodontics, and the curriculum and financial characteristics of orthodontic programs in the English-speaking world. METHODS: An online survey was used to question orthodontic students studying in the 93 programs worldwide in countries where the first language is English. The questionnaire was built by using the online survey tool www.surveymonkey.com, and the students were predominantly contacted directly via e-mail. RESULTS: Of the 301 respondents (an estimated response rate of 33%), the majority were men, had an average age of 29.8 years, and were mostly from programs in the United States. The mean program durations were 31.0 months in the United States and 37.1 months in the Commonwealth, with mean total patient loads of 84 and 106, respectively. Various treatment modalities were used in both groups. The mean annual tuition fee was considerably higher in the United States. The overall mean debt at graduation was $118,200, and the mean expected income 5 years after graduation was $283,200. Private practice was the most popular career path (90.3%), with fewer than a third of the respondents stating that they would consider an academic career. CONCLUSIONS: This study indicates that the demographic characteristics of orthodontic students are similar to those most recently reported, with the proportion of female students continuing to increase. The numbers of transitional dentition patients and total patient case loads are increasing, and students are being exposed to an increasingly wide range of treatment techniques. A continuing increase in tuition fees was reported, along with increased levels of debt at graduation, and fewer students intend to have an academic career.

Moments generated by simple V-bends in nickel titanium wires.

This study compared the moments produced by V-bends placed in rectangular nickel titanium (NiTi) orthodontic wire to those produced in titanium-molybdenum alloy (TMA). V-bends that included angles of 135, 150, and 165 degrees were heat set into 0.017×0.025 and 0.016×0.025 inch NiTi alloy wires and identical bends bent into TMA wires with a dimension of 0.018×0.025 and 0.016×0.022 inch. There were five specimens per group (N=60). The moments produced by each specimen were tested on a custom jig that aligned two lower incisor brackets with zero tip or torque at an interbracket distance of 15 mm. The upper bracket was connected to a moment transducer. The V-bend position for each specimen was varied in 1 mm increments towards the moment transducer. The moments produced by TMA wires were linear, which increased as the V-bend approached the transducer, while NiTi exhibited a non-linear curve characterized by a flattening of the moment value. The point of dissociation (where the moment experienced by the bracket became zero) was estimated for both wire types using linear mixed model analysis. For TMA wires, this point was similar to that reported in the literature but was significantly less for NiTi wire when compared with TMA. The moments produced by TMA generally increased with the magnitude of the V-bend, whereas this was not the case for NiTi.

Changes in malocclusion over time in New Zealand adolescents.

BACKGROUND: The Dental Aesthetic Index (DAI) has been used in many cross-sectional studies of population samples, but its use in assessing changes in malocclusion is less common. The aim of the present study was to describe the natural history of malocclusion and investigate the utility of the DAI as a measure for describing changes in malocclusion in a population-based sample of adolescents. METHOD: A repeat examination was conducted of a sample of 430 children first assessed in 2003 at age 13 and re-examined at age 16 (255 or 59.3 per cent of the baseline sample) with their DAI and orthodontic history recorded at each age. RESULTS: Of the adolescents re-assessed, 28 were in active orthodontic treatment, 30 had completed treatment and 197 had not received any treatment. There were substantial changes in the DAI items from age 13 to 16, with the greatest improvement in maxillary anterior irregularity. Overall, almost one-quarter of participants showed an improvement in their DAI treatment need category which was considerably higher among those who had either received treatment or were in treatment. CONCLUSION: The DAI is a valid and responsive tool for measuring change in malocclusion over time. Anterior mandibular irregularity shows the greatest change with age, and orthodontic treatment is effective in treating malocclusion, at least in the short-term.

The effect of a Clark twin block on mandibular motion: a case report.

AIMS: To investigate mandibular motion in six degrees of freedom before, during and after twin block treatment in one individual. METHODS: The appliance was worn for eight months, and motion recordings, using a 12-camera opto-electric system, were captured prior to placement of a twin block appliance and 2, 4, 14 and 52 weeks after insertion. RESULTS: The wide variations in mandibular motion that accompany twin block wear disappeared post-treatment, except for an increase in anteroposterior movement of the mandible. CONCLUSION: Twin block therapy appears to affect mandibular motion temporarily.

Moment-to-force characteristics of preactivated nickel-titanium and titanium-molybdenum alloy symmetrical T-loops.

INTRODUCTION: This in-vitro study investigated the loads (forces), moments, and moment-to-force ratios (M:F) generated during the activation and deactivation of T closing loops made of rectangular nickel-titanium (NiTi) and titanium-molybdenum alloy (TMA) wires incorporating either 0 degrees, 15 degrees, or 30 degrees of preactivation. METHODS: T-loop designs were formed in the wires by using a standard template, and, for the NiTi alloys, a temperature of 510 degrees C for 9 minutes was used. Forces and moments of the T-loops were measured at 35.6 degrees C +/- 0.5 degrees C, and these were used to calculate the M:F ratio. Analysis of covariance was used to identify statistical differences between wire alloy and preactivation. RESULTS: Nonpreactivated (0 degrees) closing loops failed to produce an optimum M:F ratio for translational tooth movement. With increasing preactivation, the M:F ratio increased over the deactivation range for both alloys. The NiTi T-loops produced an M:F ratio of greater than 10:1 over a larger deactivation range (while still delivering a force of 50-150 g) than for the equivalent TMA T-loop. The difference in M:F between the 0 degrees and 30 degrees TMA loops was statistically significant (P <0.000) but not between the equivalent NiTi loops (P <0.136). There was no statistical difference between the NiTi wire alloys at any preactivation angulation. CONCLUSIONS: Optimum M:F ratios for orthodontic translation can be achieved by using preactivated NiTi and TMA T-loops, with NiTi loops maintaining the optimum M:F ratio over a greater range of deactivation.

Temperature effects on the forces, moments and moment to force ratio of nickel-titanium and TMA symmetrical T-loops.

OBJECTIVE: To test the null hypothesis that temperature has no effect on the force, moment, and moment to force ratio (M:F) of nickel-titanium (NiTi) and titanium molybdenum alloy (TMA) T-loops. MATERIALS AND METHODS: Twelve symmetrical T-loops were constructed from NiTi and TMA rectangular wires (N = 24). For each material, four specimens had 30 degrees preactivation bent into the legs, four had 15 degrees , and the remainder no preactivation. The specimens were mounted on a custom stand incorporating a force and a moment transducer housed in an insulated oven in which the temperature was varied from 10 degrees C to 50 degrees C in 10 degrees increments (+/-0.5 degrees C). The loops were opened in 1-mm increments to a maximum of 8 mm and allowed to return to the rest position. Forces and moments were recorded at each interval; from this, the M:F was calculated. Mixed-model statistical analysis was used to detect differences between mean results of material type, preactivation, and temperature. RESULTS: Temperature significantly influenced the forces and moments (P < .000) produced by NiTi closing loops, with values increasing as the temperature increased. The M:F ratios of NiTi loops were less affected, with no significant changes with temperature for the 15 degrees and 30 degrees preactivation loops, although some change was noted for the non-preactivated loops. TMA wires showed significance for some force measurements, but were generally not influenced by temperature. CONCLUSION: The hypothesis is rejected. Temperature significantly affected the forces and moments produced by NiTi T-loops, though these changes generally do not affect the overall M:F ratio.

Breakages using a unilateral fixed functional appliance: a case report using The Forsus Fatigue Resistant Device.

Fixed functional appliances are designed to provide a simple non-compliant solution to orthodontic Class II treatment. Molar correction can be achieved very quickly using these appliances, but the clinician should be wary of unexpected breakages. This case report documents such an occurrence using a unilateral fixed functional appliance.

The impact of the popular media on cosmetic dentistry.

UNLABELLED: The popular media's influence on social norms with respect to people's appearance is likely to have played a part in the recent growth of cosmetic dentistry. AIMS: This study was designed to investigate the manner in which the popular media have affected the perception and delivery of aesthetic dentistry in New Zealand. METHODS: A nationwide survey was posted to a random sample of 600 general dental practitioners (GDPs) requesting sociodemographic details and information on the types of aesthetic dental procedures provided and the demand for those. Information was also sought on GDPs' awareness of television programmes and reality "makeover" television shows (such as "Extreme Makeover") covering issues related to aesthetic dentistry, together with the impact of such programmes (and that of different print media) on their patients' perceptions of, and demand for, aesthetic dentistry. RESULTS: The response rate was 81.2 percent. A majority of participants perceived an increased demand for tooth whitening (77.8 percent) and veneers (54.8 percent) subsequent to the airing of those television programmes, with 85.2 percent reporting patients mentioning "Extreme Makeover" in relation to aesthetic dentistry. Some 56.8 percent believed that patients had higher aesthetic expectations subsequent to the airing of that programme. An increased demand for tooth whitening was reported by more female than male GDPs, and also by younger practitioners and those who were practising in larger centres. Similar patterns were observed with respect to GDPs recommending tooth whitening for patients. Women's magazines were ranked by GDPs as having the highest impact on patients' perceptions of aesthetic dentistry. CONCLUSION: The popular media (especially television) appear to have had an impact on the demand for various aesthetic dental procedures in New Zealand.

The big OE: New Zealand dental graduates' self-reported experience of working overseas.

UNLABELLED: Recent dental workforce reports have highlighted a poorer-than-expected cohort remainder rate for recent New Zealand dental graduates, and it is not currently clear whether this trend reflects the permanent loss of some of New Zealand's new dental workforce, or is the continuation of what may be considered to have been a "rite of passage" for new dental graduates. OBJECTIVES: To examine the working and travelling patterns (if any) of New Zealand dental graduates, specifically to ascertain the most common countries in which New Zealand graduates have practised, the number of years of experience acquired before leaving, and the length of time spent overseas before returning. METHODS: A nationwide survey was posted to a random sample of 600 general dental practitioners (GDPs) requesting sociodemographic details and information on whether or not they had practised dentistry overseas. RESULTS: The response rate was 81.2 percent, and 368 of the 449 respondents were NZ graduates. Overall, 215 (58.4 percent) had practised overseas. The United Kingdom (47.6 percent) and Australia (9.8 percent) were the two most common countries for those who had done so. A larger proportion of male practitioners had practised outside New Zealand, and those who graduated earlier were also more likely to have practised overseas, and in the United Kingdom. After controlling for gender, those with 15-30 years in practice were 2.4 times more likely to have practised overseas (95 percent CI 1.5, 4.0), while those with 31+ years of experience were 4.4 times more likely to have done so (95 percent CI 2.4, 8.2). CONCLUSION: Despite some recent changes, gaining experience overseas continues to be a feature of practice for New Zealand dental graduates.

Cephalometric correction factors for bite opening--a dry skull study.

The lateral cephalometric radiograph supplies the clinician with valuable information regarding the facial skeletal morphology of the patient, provided that it is taken correctly. These radiographs should be taken while the patient is occluding in maximum intercuspation, failing which the exposure is often repeated, leading to an increase in patient radiation dose as well as added cost in time and materials. This study investigated the relationship between limited bite opening and selected cephalometric variables. Thirty-one dry skulls were used and five splints were constructed for each skull giving increments of bite opening from 0 to 5 mm. Six lateral radiographs per skull were taken at each increment of bite opening. The radiographs were traced and the points plotted using a reflex metrograph. A linear relationship was found between bite opening and SNB, ANB, SN-mandibular plane, and SN-Y-axis angles. Errors in digitization, superimposition, and landmark identification were determined and found to be acceptable. Regression analysis produced a highly significant (P < 0.001) gradient for each of these angular relationships, allowing a set of correction factors to be produced, which can be applied to bite openings up to 5 mm.

Office reconditioning of stainless steel orthodontic attachments.

An investigation was conducted to determine a simple, effective method for reconditioning stainless steel orthodontic attachments in the orthodontic office. In total, 100 new brackets were bonded to premolar teeth, then debonded and the bond strength recorded as a control for the reconditioning process. The debonded brackets were divided into six groups and each group reconditioned using different techniques as follows: attachments in four groups were flamed and then either (1) sandblasted, (2) ultrasonically cleaned, (3) ultrasonically cleaned followed by silane treatment, (4) rebonded without further treatment. Of the two remaining groups, one was sandblasted, while the brackets in the other were roughened with a greenstone. The brackets were rebonded to the premolar teeth after the enamel surfaces had been re-prepared, and their bond strengths measured. The results indicated that sandblasting was the most effective in removing composite without a significant change in bond strength compared with new attachments. Silane application did not improve the bond strength values of flamed and ultrasonically cleaned brackets. Attachments that had only been flamed had the lowest bond strength, followed by those that had been roughened with a greenstone.

The Down syndrome patient in dental practice, Part II: clinical considerations.

Down syndrome (DS), or Trisomy 21, is a genetic disorder which results in intellectual impairment, typical craniofacial features and a wide spectrum of phenotypic abnormalities (reviewed by Kieser et al, 2003). Despite a large volume of research into this condition, its prevalence remains high (1 in 700 live births - Serra and Neri, 1990; Reeves, 2000). This, together with a notable increase in life expectancy (Pilcher, 1998), improved health care and a greater degree of integration into society in New Zealand has resulted in an increased demand for dental care.

Moment to force ratio characteristics of three Japanese NiTi and TMA dosing loops.

OBJECTIVES: This in vitro study investigated the loads ("forces"), moments and moment:force ratios (M:F) generated during activation and deactivation of three closing loop designs constructed from two different orthodontic wire alloys. METHOD: The forces and moments of non-preactivated vertical U-Loops, symmetrical T-Loops, and asymmetrical T-Loops (X-Loops) made from titanium molybdenum alloy (TMA) and Japanese nickel titanium alloy (NiTi) were measured at 35.6 degrees C +/- 0.5 degrees C. The M:F ratios generated during activation and deactivation were calculated for each loop. Analysis of covariance was used to identify statistical differences between loop material and design. RESULTS: The forces, moments and M:F ratios produced by the NiTi closing loops were significantly less than those from the TMA loops. NiTi T-Loops produced a relatively constant force during activation compared to the same design in TMA. The TMA X-loop produced a maximum M:F ratio of 9.4:1. No closing loop produced the optimum M:F ratio required for translational en masse tooth movement. CONCLUSIONS: Optimum M:F ratios for translation are not possible with non-preactivated vertical U-Loops, symmetrical T-Loops, and asymmetrical T-Loops (X-Loops) made of NiTi and TMA alloys.

The Down syndrome patient in dental practice, part I: Pathogenesis and general and dental features.

Down syndrome (DS) is an autosomal chromosomal anomaly which results from trisomy of all or part of chromosome 21. It is the single most common genetic cause of mental retardation affecting approximately 1 in 700 live births. Since its first description in 1866 by John Langdon Down, much research has focused on this condition. In the past two decades there has been a significant increase in information about its causes, diagnosis and medical and dental consequences. In this, the first of two articles, we pay tribute to the work of Harvey Brown, and we review the pathogenesis, general and cranio-dental features of Down Syndrome. The cause of DS is usually non-dysjunctive trisomy 21, with 91 percent of cases being maternally derived. Uncommon causes are mosaicism or translocation from other chromosomes. DS patients suffer from congenital cardiopathies, growth retardation, endocrinopathies, sleep apnoea, neoplasias and early-onset Alzheimer's disease. Typically, craniofacial features include midfacial hypoplasia with a resultant flattened face, ocular hypotelorism and mandibular prognathism. The universal characteristic of the DS face is the upward slanting of the palpebral fissures and epicanthic folds. Dental features include tooth size reduction, hypodontia, reduced root lengths, changes in tooth shape and excessive tooth wear.