A longitudinal controlled study of factors associated with mutans streptococci infection and caries lesion initiation in children 21 to 72 months old

Purpose: The purpose of this longitudinal study was to determine factors associated with mutans streptococci (MS) infection and development of caries lesions in a group of children 21 to 72 months old. Methods: The 63 caries-free children, recruited since birth, were divided into: (1) a study group of 24 children who were colonized with MS; and (2) a control group of 39 children without MS. The children were recalled every 3 months for approximately 24 months, and their social, medical, and dental histories were updated. At each recall, the teeth were checked for presence or absence of plaque, enamel hypoplasia, and caries lesions, and their MS status was assessed using a commercial test kit. Results: MS infection was associated with: (1) visible plaque (P < .01); (2) enamel hypoplasia (P < .05); (3) commencement of tooth-brushing after 12 months of age (P < .05); (4) lack of parental assistance with tooth-brushing (P < .025); and (5) increased hours of child care/school (P < .05). Four children (20%) were colonized at an age range of 21 to 36 months, 9 (45%) at 37 to 48 months, and 7 (35%) at 49 to 72 months (P < .001). Eight children who developed caries lesions: (1) had more hypoplastic teeth (P < .001); (2) ate sugar-containing snacks (P < .05); and (3) did not brush regularly with chlorhexidine gel (P < .01) compared to those who remained free of caries lesions. Conclusions: Lack of oral hygiene, consumption of sugar-containing snacks, and enamel hypoplasia are significant factors for both MS infection and caries lesion initiation.

Protocol for the Hall Technique study: A trial to measure clinical effectiveness and cost-effectiveness of stainless steel crowns for dental caries restoration in primary molars in young children

BACKGROUND: The Hall Technique (HT) is a carious primary molar treatment that does not require local analgesia, carious tissue removal or tooth preparation. The carious lesions in carefully selected teeth are sealed with a stainless steel crown (preformed metal crown). The study aims are to determine the clinical effectiveness, acceptability and cost-effectiveness of the HT for management of carious lesions in young dental patients. METHODS/DESIGN: Children, aged 3-7years, with a primary molar tooth with a carious lesion extending no further than the middle third of dentine, with no signs or symptoms of pulp inflammation or infection, and attending one of three community agencies are recruited. Target sample size is 220. A control tooth with an intra-coronal restoration is sourced from the same mouth. The primary outcome is the period of time free from further treatment. The assessments are scheduled at 6, 12 and 24months. In addition to the clinical assessment, acceptability of the HT will be assessed via questionnaires among patients and their primary carers at baseline, 6, 12 and 24months. Cost-outcome description and cost-effectiveness analysis from healthcare provider and societal perspective will be conducted. DISCUSSION: The clinical effectiveness, acceptability and cost-effectiveness of the HT in the community dental setting will be evaluated. The results of this study will determine the implementation of HT in the management of dental caries in young children.

Correcting for bias when estimating the cost of hospital-acquired infection : an analysis of lower respiratory tract infections in non-surgical patients

Hospital acquired infections (HAI) are costly but many are avoidable. Evaluating prevention programmes requires data on their costs and benefits. Estimating the actual costs of HAI (a measure of the cost savings due to prevention) is difficult as HAI changes cost by extending patient length of stay, yet, length of stay is a major risk factor for HAI. This endogeneity bias can confound attempts to measure accurately the cost of HAI. We propose a two-stage instrumental variables estimation strategy that explicitly controls for the endogeneity between risk of HAI and length of stay. We find that a 10% reduction in ex ante risk of HAI results in an expected savings of £693 ($US 984).

Experimental Infection of Culex Annulirostris, Culex Gelidus, and Aedes Vigilax With a Yellow Fever/Japanese Encephalitis Virus Vaccine Chimera (Chimerivax TM-JE)

Australian mosquitoes from which Japanese encephalitis virus (JEV) has been recovered (Culex annulirostris, Culex gelidus, and Aedes vigilax) were assessed for their ability to be infected with the ChimeriVax-JE vaccine, with yellow fever vaccine virus 17D (YF 17D) from which the backbone of ChimeriVax-JE vaccine is derived and with JEV-Nakayama. None of the mosquitoes became infected after being fed orally with 6.1 log(10) plaque-forming units (PFU)/mL of ChimeriVax-JE vaccine, which is greater than the peak viremia in vaccinees (mean peak viremia = 4.8 PFU/mL, range = 0-30 PFU/mL of 0.9 days mean duration, range = 0-11 days). Some members of all three species of mosquito became infected when fed on JEV-Nakayama, but only Ae. vigilax was infected when fed on YF 17D. The results suggest that none of these three species of mosquito are likely to set up secondary cycles of transmission of ChimeriVax-JE in Australia after feeding on a viremic vaccinee.

Springboards into design : exploring multiple representations of interaction in a dental surgery

This paper demonstrates that in order to understand and design for interactions in complex work environments, a variety of representational artefacts must be developed and employed. A study was undertaken to explore the design of better interaction technologies to support patient record keeping in a dental surgery. The domain chosen is a challenging real context that exhibits problems that could potentially be solved by ubiquitous computing and multi-modal interaction technologies. Both transient and durable representations were used to develop design understandings. We describe the representations, the kinds of insights developed from the representations and the way that the multiple representations interact and carry forward in the design process.

A participatory design agenda for ubiquitous computing : a case study in dental practice

This paper reflects upon our attempts to bring a participatory design approach to design research into interfaces that better support dental practice. The project brought together design researchers, general and specialist dental practitioners, the CEO of a dental software company and, to a limited extent, dental patients. We explored the potential for deployment of speech and gesture technologies in the challenging and authentic context of dental practices. The paper describes the various motivations behind the project, the negotiation of access and the development of the participant relationships as seen from the researchers' perspectives. Conducting participatory design sessions with busy professionals demands preparation, improvisation, and clarity of purpose. The paper describes how we identified what went well and when to shift tactics. The contribution of the paper is in its description of what we learned in bringing participatory design principles to a project that spanned technical research interests, commercial objectives and placing demands upon the time of skilled professionals.