Does performance in selection processes predict performance as a dental student?

OBJECTIVE: This study investigated associations between the performance of dental students in each of the three components of the selection procedure [academic average, Undergraduate Medicine and Health Sciences Admission Test (UMAT) and structured interview], socio-demographic characteristics and their academic success in an undergraduate dental surgery programme. MATERIALS AND METHODS: Longitudinal review of admissions data relating to students entering dental education at the University of Otago, New Zealand, between 2004 and 2009 was compared with academic performance throughout the dental programme. RESULTS AND DISCUSSION: After controlling for variables, pre-admission academic average, UMAT scores and interview performance did not predict performance as a dental student. Class place in second year, however, was a strong predictor of class place in final year. Multivariate analysis demonstrated that the best predictors of higher class placement in the final year were New Zealand European ethnicity and domestic (rather than international) student status. Other socio-demographic characteristics were not associated with performance. These interim findings provide a sound base for the ongoing study. CONCLUSION: The study found important socio-demographic differences in pre-admission test scores, but those scores did not predict performance in the dental programme, whether measured in second year or in final year.

Self-reported occupational health of general dental practitioners.

BACKGROUND: Limited information is available regarding the occupational health status of dentists (particularly in New Zealand), although previous research suggests that stress, hand dermatoses and musculoskeletal symptoms are common. AIMS: To determine the occupational health status of New Zealand dentists. METHODS: A nationwide postal survey of a representative sample of 750 dentists. RESULTS: There was a response rate of 77%. Most dentists (71%) reported their general health as very good or excellent; 43% rated their physical fitness as excellent or very good and 64% were happy and interested in life. Workplace bullying had been experienced by 19% and was higher for female and employee dentists and 29% had experienced a violent or abusive incident at work. Almost half of the sample (47%) had experienced at least one dermatitis-type condition in the previous 12 months. The most commonly reported sites for musculoskeletal problems experienced in the previous year were the neck (59%), lower back (57%) and shoulders (45%). Women had a higher prevalence of several occupational health problems, but were more satisfied with their overall health than male dentists. CONCLUSIONS: The majority of dentists had good general health, but physical fitness levels were not ideal. The prevalence of hand dermatoses and musculoskeletal problems are high and impact significantly on dentists' daily lives. Interventions such as reducing weight and training in optimal working methods to reduce musculoskeletal problems and injuries (such as eye or needlestick incidents) might improve the health of this workforce but further research is required.

Job stressors of New Zealand dentists and their coping strategies.

BACKGROUND: Dentistry is understood to be a stressful profession. Although there has been recent research about stress and dentistry in the UK and the Netherlands, little is known about the job stressors and coping strategies of New Zealand dentists. AIM: To investigate job stressors and coping strategies among New Zealand dentists. METHODS: A nationwide postal survey of a representative sample of 700 dentists. RESULTS: The response rate was 65%. The most commonly reported stressors were treating difficult children (52%), constant time pressure (48%) and maintaining high levels of concentration (43%). The strategies most utilized for managing work-related stress included interactions with people (78%), sports (64%) and forgetting about work (59%). Dentists who had graduated overseas reported more sources of stress than New Zealand graduates. There were differences in the strategies used by male and female practitioners to manage stress. CONCLUSIONS: There is considerable variation in the number of stressors experienced by dentists. Overseas-qualified dentists appear to be under more stress than New Zealand-trained dentists and may need greater professional support. Dentists should be encouraged to make greater use of active coping strategies.

The working practices and career satisfaction of dental therapists in New Zealand.

OBJECTIVE: To describe the working practices and level of career satisfaction of dental therapists in New Zealand. DESIGN: Postal survey of dental therapists identified from the New Zealand Dental Council's dental therapy database. One mailing with one follow-up. PARTICIPANTS: Questionnaires were sent to 683 registered dental therapists. Replies were received from 566 (82.9%). OUTCOME MEASURES: Current working practice, career breaks, continuing education, career satisfaction. RESULTS: Respondents had a high career satisfaction, but were much less satisfied with their remuneration. After controlling for age and income satisfaction, therapists who felt that they were valued members of the dental community had over four times the odds of having higher overall job satisfaction. There were no differences in the mean career satisfaction scale score by age, but respondents aged 45 and over had a lower mean income satisfaction scale score than their younger counterparts (p<0.05). Older respondents were more likely to report regularly placing fissure sealants (p<0.05), participating in peer review (p<0.05), and playing a role in team management/coordination (p<0.05) than younger respondents. Most therapists (412; 82.2%) had taken at least one career break, usually for child rearing. A mean of 6.5 years (SD 5.9; range six weeks to 25 years) had been taken in career breaks. Younger therapists were more interested in moving into private practice than their older colleagues (p<0.05). More than half of respondents planned to retire from dental therapy within 10 years. CONCLUSION: Urgent action is required to improve the recruitment and retention of dental therapists in the New Zealand School Dental Service. Measures to reduce the time taken in career breaks could increase the productivity of this workforce. Remuneration and career progression are key issues; therapists need to feel that they are valued members of the dental profession.

Dental caries experience and use of dental services among preschool children in Ajman, UAE.

OBJECTIVE: The aim of this study was to estimate the prevalence and severity of dental caries in the primary dentition of young children in Ajman, UAE, and investigate its association with sociodemographic characteristics and use of dental services. METHODS: A cluster-sampling approach was used to randomly select children aged 5 or 6 years who were enrolled in public or private schools. Clinical examinations for caries were conducted by a single examiner using World Health Organization criteria. Parents completed questionnaires seeking information on socioeconomic background and dental service utilization. Zero-inflated negative binomial (ZINB) regression modelling was used to identify risk markers and risk indicators for caries experience. RESULTS: The prevalence of dental caries in the sample was high 76.1%. The average dmfs score 10.2. Caries severity was greater among older children and among male children of less educated mothers. Emirati (local) children had higher caries severity than others. Children who had higher level of caries visited the dentist more frequently than other children whose visits were for check-up only. CONCLUSIONS: Dental caries prevalence and severity in young children in Ajman are high, and socioeconomic characteristics and dental utilization are important determinants of their dental caries experience. There is an urgent need for oral health programmes targeted at the treatment and underlying causes of dental caries in these children.

Socioeconomic inequalities in oral health in childhood and adulthood in a birth cohort.

OBJECTIVES: To determine whether adult oral health is predicted by (a) childhood socioeconomic advantage or disadvantage (controlling for childhood oral health), or (b) oral health in childhood (controlling for childhood socioeconomic advantage or disadvantage), and whether oral health in adulthood is affected by changes in socioeconomic status (SES). METHODS: Participants in a longstanding cohort study underwent systematic dental examination for dental caries and tooth loss at ages 5 and 26 years. The examination at age 26 years included the collection of data on periodontal attachment loss and plaque level. Childhood SES was determined using parental occupation, and adult SES was determined from each study member's occupation at age 26 years. Regression models were used to test the study hypotheses. RESULTS: Complete data were available for 789 individuals (47.4% female). After controlling for childhood oral health, those who were of low SES at age 5 years had substantially greater mean DFS and DS scores by age 26 years, were more likely to have lost a tooth in adulthood because of caries, and had greater prevalence and extent of periodontitis. A largely similar pattern was observed (after controlling for childhood SES) among those with greater caries experience at age 5 years. For almost all oral health indicators examined, a clear gradient was observed of greater disease at age 26 years across socioeconomic trajectory groups, in the following order of ascending disease severity and prevalence: 'high-high', 'low-high' (upwardly mobile), 'high-low' (downwardly mobile) and 'low-low'. CONCLUSION: Adult oral health is predicted by not only childhood socioeconomic advantage or disadvantage, but also by oral health in childhood. Changes in socioeconomic advantage or disadvantage are associated with differing levels of oral health in adulthood. The life-course approach appears to be a useful paradigm for understanding oral health disparities.

The involvement of New Zealand dentists in smoking cessation interventions.

OBJECTIVES: To determine the attitudes and practices of dentists towards smoking cessation interventions (SCI), to identify perceived barriers to providing SCI, and to determine the level of interest in future training in smoking cessation for dental staff. DESIGN: Self-administered questionnaire. SUBJECTS AND METHODS: 204 NZDA members in Wellington, Otago, and Southland completed a self-administered questionnaire about SCI. RESULTS: There has been little change in attitudes and practices of dentists towards SCI over the last decade. Few are actively involved in providing these services for their patients. Most dentists believe that there are significant barriers to providing SCI in their daily practice. CONCLUSION: Dentists require greater access to appropriate forms of training in SCI, and increased support (including resources) in order to increase the level of SCI provided in the dental setting.

Is attention-deficit hyperactivity disorder a risk factor for dental caries? A case-control study.

Experience in practice has suggested that children with attention-deficit hyperactivity disorder (ADHD) tend to have higher numbers of diseased, missing and filled teeth (DMFT score) than children without the condition. To date, however, this impression has not been systematically investigated. A case-control study of children in Otago, New Zealand (case DMFT > or = 5; control DMFT <5; case status determined from School Dental Service dental records) was conducted by postal survey and reference to the School Dental Service records. Cases and controls were matched on age, sex, ethnicity, and school socio-economic status. The purpose of the study was to assess whether having ADHD was associated with higher odds of having high caries experience. Questionnaires were returned for a total of 128 case-control pairs. Conditional logistical regression analysis showed that, after controlling for fluoride history, medical problems, diet, and self-reported oral hygiene, children with ADHD had nearly 12 times the odds of having a high DMFT score than children who did not have ADHD (OR = 11.98; 95% CI 1.13, 91.81). No other factors were significant predictors. Dental practitioners and parents should consider ADHD to be a condition that may affect children's dental caries experience.

Management of a simple anterior crossbite in a child with autism: a review and case report.

This case report describes a simple treatment used to correct an anterior crossbite in a child with autism. A review of autism and the treatment of simple anterior crossbite are given. It is possible for children with special needs to be managed in the general practice setting, although treatment plans may need to be modified to meet the capabilities of individual patients. Follow-up is required for cases of anterior crossbite treated in the early mixed dentition.

Risk indicators for tooth wear in New Zealand school children.

AIM: To investigate the prevalence and severity of tooth wear in the primary dentition of a representative sample of New Zealand school children and relate these to possible risk factors. DESIGN: A cross-sectional study. SETTING: Primary schools in Dunedin, New Zealand. PARTICIPANTS: 104 children of both sexes, aged between 5 and 8 years, randomly selected. METHODS: Clinical examinations of the buccal, occlusal/incisal and lingual surfaces of deciduous canines and molars. MAIN OUTCOME MEASURE: Degree of wear and the presence of dentinal cupping of teeth. Information on weaning and consumption of fruit-based drinks at bed time, frequency of consumption of fruits, yoghurt, pickled foods, fizzy and fruit-based drinks. RESULTS: The prevalence of tooth wear was similar in boys and girls and there were no significant differences between sides of the arches. A high percentage (82%) of children had at least one primary tooth with dentine exposed. While maxillary canines showed the greatest prevalence of dentine exposed, maxillary molars displayed the greatest prevalence of cupping. Severe tooth wear was less prevalent among children weaned after 12 months (14.3%) than those weaned earlier (27.9% P < 0.01). There were no statistically significant associations between wear and the consumption of fruit, yoghurt, pickled foods, fizzy drinks or fruit-based drinks. CONCLUSIONS: Tooth wear associated with dentine exposure is common in 5-8 year old children. This is not significantly associated with dietary factors, but appears to be related to early weaning from the breast.

Leukaemia in children. Part I: Orofacial complications and side-effects of treatment.

Significant orofacial complications of leukaemia in children include lymphadenopathy, spontaneous gingival bleeding, labial and lingual ecchymoses and mucosal petechiae, ulceration, gingival swelling, and infections. The dentist may be the first to notice signs of the illness. Treatment of leukaemia can result in serious orofacial problems which include oral mucositis and ulceration, infections, spontaneous gingival bleeding, neuropathy, xerostomia, and gingival hypertrophy. A prompt diagnosis leading to early intervention can decrease the morbidity and mortality of the disease and its treatment.

Mechanomyographic and electromyographic responses during fatigue in humans: influence of muscle length.

Mechanomyography (MMG) provides a measure of muscle mechanical changes during contractions. The purpose of this study was to quantify alterations in MMG signals during fatigue at two muscle lengths. Comparisons with electromyographic (EMG) recordings were made. A group of 13 subjects performed isometric dorsiflexions (50% of maximum for 60 s) at 40 degrees of plantarflexion (long, l(l)) and 5 degrees of dorsiflexion (short, l(s)). The mean power frequency of the EMG (f(EMG)) and MMG (f(MMG)) signals and the mean rectified MMG (rMMG) and EMG (rEMG) were determined over each 1-s period, normalized to the respective maximal value, regressed against time, and the resulting slopes (units = %max. s(-1)) were analyzed. The slopes were larger (P = 0.007) at l(l) compared to l(s) [mean l(l) 0.50 (SD 0.26), mean l(s) 0.27 (SD 0.16)], however there were no differences (P = 0.24) between mean fMMG slopes [l(l) -0.10 (SD 0.16), l(s) -0.16 (SD 0.11)]. Similarly, slopes were larger (P = 0.001) at l(l) versus l(s) [l(l) 0.26 (SD 0.13), l(s) 0.08 (SD 0.15)] and there were no differences (P=0.89) between mean fEMG slopes [l(l) -0.15 (SD 0.14), l(s) -0.14 (SD 0.12)]. At 5 s following the exercise to fatigue mean MVC (units = %max) were not significantly different between l(l) and l(s) [P = 0.08; l(l) 78.8 (SD 9.1), l(s) 85.2 (SD 6. 0)]. These results showed that during fatiguing contractions, MMG and EMG amplitudes increased while frequency characteristics decreased at both muscle lengths. The change in and was greater at l(l) but no differences in fMMG or fEMG slopes occurred between lengths. These results would suggest that larger increases in motor unit recruitment occur with time during fatigue at l(l) compared to l(s).

Leukaemia in children. Part II--Dental care of the leukaemic child, including management of oral side effects of cancer treatment.

The treatment of a leukaemic child requires a multidisciplinary approach. The dental team should provide interceptive and preventive measures prior to the commencement of therapy whenever possible. During therapy, preventive and palliative measures are essential. Once remission is achieved, the child continues to have increased dental needs due to the effects of treatment. These needs may include an increased caries rate, dental maldevelopment, and secondary malignancy.

Open wide.

Dentists who work with children can appreciate the difficulties encountered when attempting to provide high quality restorative care within a confined space. In this presentation, I will address the issue of how to maximize space available in the mouth whilst minimizing patient discomfort and maintaining a working position that does not cripple the operator! Topics covered include: Instruments which take up less space in the mouth Behavioural techniques and aids to maximize mouth opening Adaptation of dental equipment for use in the child patient Techniques to obtain radiographs with minimal discomfort Methods for administering local anaesthetic with less fuss Novel methods of rubber dam placement. Space within the dental surgery is also limited. A further issue to be addressed is the management of the whanau/family to optimize their presence in supporting the patient, yet minimize distractions within the confines of the surgery.

Halitosis: causes, diagnosis, and treatment.

Halitosis is a major concern to the general public and the source of a multimillion-dollar industry world wide. Although the aetiology may be localised to the oral cavity in up to 90 percent of instances, halitosis may indicate a serious underlying medical condition necessitating medical referral. In general, halitosis of an oral cause can be safely and easily diagnosed and treated by the general dental practitioner.

A transplacental carcinogenicity bioassay in CD-1 mice with zidovudine.

In oral carcinogenicity bioassays, zidovudine (ZDV) induced vaginal epithelial cell tumors in mice given 30 or 40 mg/kg/day and rats given 300 mg/kg/day. To determine if lifetime exposure to ZDV, beginning perinatally, would alter this pattern of carcinogenicity, two groups of 60 pregnant CD-1 mice were given 20 or 40 mg/kg/day of ZDV in 0.5% methyl cellulose from Gestation Day 10 through Lactation Day 21. At weaning, 2 pups per sex from each of 35 litters in each group were assigned to the study and given 20 or 40 mg/kg/day of ZDV in the drinking water until 17-35 days of age, followed by daily gavage for 24 months. Two additional groups of 60 pregnant CD-1 mice each were given 40 mg/kg/day of ZDV daily from Gestation Day 10 through Lactation Day 21; in one, ZDV treatment was halted at weaning and in the other, treatment was stopped 90 days after weaning. Two other groups of 60 pregnant CD-1 mice were left untreated (environmental control) or were given 0.5% methyl cellulose beginning on Gestation Day 10 (vehicle control). Vehicle control progeny received plain drinking water for 17-35 days postweaning and then 0.5% methyl cellulose daily by gavage for 24 months. ZDV treatment did not affect survival or body weight in either sex. In females given 20 or 40 mg/kg/day of ZDV for 24 months there was mild macrocytic anemia. Similar, non-dose-related changes were seen in males in these groups. ZDV-related tumor findings were limited to the vagina, where there were 2 and 11 vaginal squamous cell carcinomas in mice given 20 or 40 mg/kg/day of ZDV daily, respectively. This incidence was not remarkably different from that seen in previously reported bioassays. It was concluded that lifetime oral treatment of mice with ZDV, beginning perinatally, did not alter the previously reported pattern of carcinogenicity and that under the conditions tested ZDV was not a transplacental carcinogen.

Dental disease levels and reasons for emergency clinic attendance in patients seeking relief of pain in Auckland.

This study examined the reasons for attendance, duration of the problem, treatment expectations and oral health of patients seeking relief of pain at Auckland hospital dental departments and a private accident and emergency clinic. One-third of hospital-clinic participants and 15 percent of private-clinic participants had delayed treatment for more than 1 month. Sixty-three percent of hospital-clinic and 30 percent of private-clinic participants expected to receive an extraction. The hospital-clinic group had a mean of 5.0 (SD 3.9) decayed teeth, and the private clinic group a mean of 2.3 (SD 2.8) decayed teeth. Periodontal treatment needs were also significantly higher among participants attending the hospital clinics. Twenty-five percent of hospital-clinic participants had complex periodontal treatment needs. Further research is required to estimate the size of the population these groups represent and to investigate the reasons for these differences.

Nonclinical toxicology studies with zidovudine: acute, subacute, and chronic toxicity in rodents, dogs, and monkeys.

In single dose acute toxicity studies in CD-1 mice and CD rats, the median lethal dose (MLD) for zidovudine (ZDV) was > 750 mg/kg after iv dosing and > 3000 mg/kg after po administration (recommended human dose is 100 mg every 4 hr while awake). Because of the short half-life in rats (0.8 hr), dogs (1.0 hr), and monkeys (0.8 hr), the daily dose of ZDV in most studies was given in two equal portions approximately 6 hr apart. Intravenous administration of ZDV was well tolerated in beagle dogs at dose levels up to 42.5 mg/kg bid for 2 weeks and in CD rats at dose levels up to 75 mg/kg bid for 4 weeks. In a 2-week dose range-finding study in beagle dogs, cytostatic effects were noted at po dose levels of 62.5 to 250 mg/kg bid in certain tissues with rapid cell replication rates. In contrast, in 3- to 12-month oral toxicity studies in CD rats and cynomolgus monkeys, the principal toxicologic finding was reversible macrocytic normochromic anemia which occurred at 225-250 mg/kg bid in rats and 17.5-150 mg/kg bid in monkeys. In the 12-month rat study, RBC was decreased at 25 and 75 mg/kg bid. In the 12-month monkey study WBC was slightly decreased at 150 mg/kg bid.

Nonclinical toxicology studies with zidovudine: reproductive toxicity studies in rats and rabbits.

Zidovudine (ZDV) was evaluated for adverse effects on reproduction and fetal development in animal test species. Standard preclinical tests for reproduction and fertility, developmental toxicity, and postnatal toxicity were conducted in CD (Sprague-Dawley) rats and a developmental toxicity study was conducted in New Zealand white rabbits. In an additional study, reproductive outcome was characterized in female rats given ZDV before, during, or after mating and drug levels in the plasma and milk of lactating rats were determined. Finally, drug exposure data including observed peak plasma concentrations (Cmax) and area under the concentration-time curve (AUC) were evaluated for pregnant rats and rabbits. In a reproduction/fertility study in CD rats, toxicity to the early rat embryo, manifested as an increase in early resorptions and a decrease in litter size, was noted following dosage of the parental animals with 75 or 225 mg ZDV/kg bid. A dose of 25 mg/kg bid was a no-effect level in rats. At the time of mating, male rats had been dosed for 85 days, and females had been dosed for 26 days. To further evaluate the effects of ZDV on reproduction, dosing of male rats was continued to 149 days when they were mated a second time to virgin, untreated females. All reproductive parameters were normal in the untreated females from this second mating, indicating that the embryotoxic effect of the drug was not likely mediated by a genotoxic or other effect in the male. A separate study in female CD rats given 225 mg/kg bid for various periods pre- or postconception suggests that the toxic effect of ZDV is primarily to the early rodent embryo. Early embryo death did not occur in rats or rabbits in standard developmental (teratology) studies; however, pregnant New Zealand white rabbits given 250 mg/kg bid during gestation Days 6-18 showed reduced weight gain, anemia, and an increase in late fetal deaths. No other evidence of developmental toxicity was noted in either species, and ZDV was not teratogenic in rats or rabbits given up to 250 mg/kg bid during the period of major organogenesis. At this dose, Cmax values in rats and rabbits were approximately 234 and 150 times higher, respectively, than the mean steady-state serum concentration in adults following chronic oral administration of 250 mg every 4 hr. In both the reproduction/fertility study and a peri- and postnatal study in rats, liveborn offspring showed no adverse effects on survival, growth, or developmental measurements.

Nonclinical toxicology studies with zidovudine: genetic toxicity tests and carcinogenicity bioassays in mice and rats.

Zidovudine (ZDV), an antiviral drug active in the treatment of acquired immunodeficiency syndrome (recommended human dose, 100 mg every 4 hr while awake), was evaluated for mutagenic and carcinogenic potential in a battery of short-term in vitro and in vivo assays and in lifetime studies in mice and rats. In L5178Y mouse lymphoma cells (tk+/- locus), a weak positive result was obtained only at the highest concentrations tested (4000 to 5000 micrograms/ml) in the absence of metabolic activation. In the presence of metabolic activation, the drug was weakly mutagenic at concentrations of 1000 micrograms/ml and higher. Following 24 hr treatment in the absence of metabolic activation, ZDV was moderately mutagenic at concentrations up to 600 micrograms/ml; dose-related structural chromosomal alterations were seen at concentrations of 3 micrograms/ml and higher in cultured human lymphocytes. Such effects were not noted at the two lowest concentrations tested, 0.3 and 1 microgram/ml, and BALB/c-3T3 cells were transformed at concentrations of 0.5 microgram/ml and higher. No effects were seen in the Ames Salmonella plate incorporation and preincubation modification assays (possibly due to bacteriocidal activity of ZDV at low concentrations) at concentrations ranging from 0.01 to 10 micrograms/plate or in a single-dose intravenous bone marrow cytogenetic assay in CD rats. In multidose micronucleus studies, increases in micronucleated erythrocytes were seen in mice at doses of 100 to 1000 mg/kg/day. Similar results were seen in rats and mice after 4 or 7 days of dosing at 500 mg/kg/day. In carcinogenicity bioassays, adjusted doses of 20, 30, or 40 mg/kg/day and 80, 220, and 300 mg/kg/day were given to CD-1 mice and CD rats, respectively, for up to 22 months in mice and 24 months in rats. ZDV caused a macrocytic, normochromic anemia in both species. No evidence of carcinogenicity was seen in male mice or rats. In female mice, five malignant and two benign vaginal epithelial neoplasms occurred in animals given 40 mg/kg/day. A single benign vaginal epithelial tumor was seen in a mouse given 30 mg/kg/day. In rats, two malignant vaginal epithelial neoplasms were seen in animals given 300 mg/kg/day. In a 7-day study in mice, ZDV was shown to be devoid of estrogenic activity. In an oral pharmacokinetics study, the AUC was 17 and 140 micrograms/ml.hr in female mice and rats given 40 or 300 mg/kg of ZDV, respectively. In contrast, the average steady-state concentration in humans at the recommended daily dose is 0.62 microgram/ml. Twenty-four hour urine concentrations were 1245 and 4417 micrograms/ml in female mice and rats given 40 or 300 mg/kg of ZDV, respectively. These values were approximately 26- and 136-fold higher than the human urine concentration at the recommended daily dose. In a one- to three-day study with intravenously administered sodium fluoroscein in rats and mice, retrograde flow of urine into the vagina was demonstrated. In a subsequent lifetime carcinogenicity bioassay in mice in which ZDV was given intravaginally at concentrations of 5 or 20 mg ZDV/ml in saline, 13 vaginal squamous cell carcinomas were seen at the highest concentration tested. It was concluded that the vaginal tumors seen in the oral carcinogenicity studies were the result of chronic local exposure of the vaginal epithelium to high urine concentrations of ZDV.