Nitrogen doped titanium dioxide as an aesthetic antimicrobial filler in dental polymers.

OBJECTIVE: To develop an aesthetic resin composite using a nitrogen-doped titanium dioxide (NTiO2) filler that possesses antimicrobial properties against cariogenic bacteria. METHODS: N-TiO2 powder was manufactured by calcining commercial TiO2 with urea. Free radical release from the N-TiO2 powder under visible light irradiation was analysed using UV-Vis spectrophotometry. The N-TiO2 powder was incorporated into a dental resin and the photocatalytic activity assessed using a dye under both visible light and dark conditions. Using XTT assay to measure the cellular metabolic activity, the antibacterial properties of the N-TiO2 /resin composite discs were tested using Streptococcus mutans. RESULTS: Doping nitrogen of TiO2 resulted in a band gap shift towards the visible light spectrum, which enabled the powder to release reactive oxygen species when exposed to visible light. When incorporated into a dental resin, the N-TiO2/resin composite still demonstrated sustained release of reactive oxygen species, maintaining its photocatalytic activity and showing an antibacterial effect towards Streptococcus mutans under visible light conditions. SIGNIFICANCE: N-TiO2 filled resin composite shows great promise as a potential aesthetic resin based adhesive for orthodontic bonding.

Reporting Discrepancy Resolved by Findings and Time in 2947 Emergency Department Ankle X-rays.

AIMS: To identify common errors in ankle X-ray reporting between initial interpretation and final assessment at the virtual fracture clinic. Also, to assess time of initial reporting as a causative factor for discrepancy. METHODS: Two thousand nine hundred forty-seven final reports were reviewed by standard of agreement to the initial interpretation. Where discrepancy was found, it was classified and collated by specific finding. Comparison was made between reports with discrepancy and the complete dataset, allowing rates of error by finding to be established. The reports containing discrepancy were further classified by time period, this was compared against an expected value to establish if initial reporting outside of routine working hours was as accurate as that conducted within routine working hours. RESULTS: 94.4% of reports were in agreement with the initial interpretation, 2.9% contained minor discrepancy, and 2.7% major discrepancy. In 45.6% of reports there was no radiologically observable injury. 16.4% of reports contained a lateral malleolar fracture, most commonly Weber type B. 40.0% of all navicular fractures, and 33.3% of all cuboidal fractures were not commented upon in the initial reporting. Lower rates of more frequently observed findings were missed with 2.5% of Weber type B fractures not commented upon. An increased proportion of major discrepancy reports were generated from 00:00 to 07:59 (expected = 15.0%, observed = 22.2%; p = 0.07908). Similarly, a greater than expected number of minor discrepancy reports were found between 20:00 and 23:59 (expected = 18.0%, observed = 34.1%, p = 0.00025). CONCLUSIONS: The initial reporting of ankle X-rays in the emergency department is performed to a high standard, however serious missed findings emphasise the need for timely senior review. Reporters should increase their awareness of navicular, cuboid, talar, and Weber A fractures which were missed at disproportionate rates. This study also finds evidence to support increased rates of error in initial reporting of ankle X-rays outside of normal working hours (17:00-07:59), particularly with a significantly increased rate of minor discrepancy seen from 20:00 to 23:59.

The confidence of undergraduate dental students when carrying out prosthodontic treatment and their perception of the quality of prosthodontic education.

INTRODUCTION: Despite the falling number of edentulous patients within the UK, there is still a large demand for the provision of removable prostheses. On qualification, dentists should have the knowledge and skills to provide these prostheses, but previous studies have shown that final-year dental undergraduate confidence in treating denture patients is lacking. AIM: To explore undergraduate dental student confidence whilst carrying out prosthodontic treatment, and to explore their perceptions of the quality of their prosthodontic education. METHOD: An anonymous questionnaire was distributed to all (n=203) dental undergraduates in Years 3 to 5 at the University of Bristol. The questionnaire utilised a range of data collection methods including confidence interval ranked responses and qualitative measures. The data were analysed using SPSS. RESULTS: The response rate was 51%. Undergraduate perception of confidence increased throughout the years of study (P<.001). There was also an increase in the number of partial and complete denture cases treated as students progressed through the course (P<.001). Overall, students were satisfied with their prosthodontic teaching, although students thought that too much time was allocated to laboratory teaching, and that increasing their clinical experience would be most beneficial in increasing their confidence levels. CONCLUSION: Student confidence in carrying out prosthetic treatment increased as students progressed through the course, and confidence levels would be increased further with increased clinical experience.

Silver doped titanium dioxide nanoparticles as antimicrobial additives to dental polymers.

OBJECTIVE: The objectives of this in vitro study were to produce a filled resin containing Ag-TiO2 filler particles and to test its antibacterial properties. METHODS: Ag-TiO2 particles were manufactured using the ball milling method and incorporated into an epoxy resin using a high speed centrifugal mixer. Using UV/vis spectrophotometry investigations were performed to assess how the photocatalytic properties of the Ag-TiO2 particles are affected when encased in resin. Adopting the bacteria colony counting technique, the antibacterial properties of Ag-TiO2 particles and Ag-TiO2 containing resins were assessed using Streptococcus mutans under varying lighting conditions. RESULTS: Ag doping of TiO2 results in a band gap shift towards the visible spectrum enabling Ag-TiO2 to exhibit photocatalytic properties when exposed to visible light. Small quantities of Ag-TiO2 were able to produce a bactericidal effect when in contact with S. mutans under visible light conditions. When incorporated into the bulk of an epoxy resin, the photocatalytic properties of the Ag-TiO2 particles were significantly reduced. However, a potent bactericidal effect was still achieved against S. mutans. SIGNIFICANCE: Ag-TiO2 filled resin shows promising antimicrobial properties, which could potentially be used clinically.

Effect of gender and Frankfort mandibular plane angle on orthodontic space closure: a randomized controlled trial.

OBJECTIVES: To determine the effect of gender and Frankfort mandibular plane angle (FMPA) on extraction space closure. SETTING AND SAMPLE POPULATION: A single district general hospital. The sample population were 11- to 18-year-olds undergoing upper and lower fixed appliance therapy following the loss of a premolar in each quadrant. METHODS: A total of 100 patients undergoing upper and lower fixed appliance therapy following the loss of four premolars were randomized with stratification on two age ranges (11-14 years and 15-18 years) and three FMPAs (high, medium and low). Allocation was to one of three treatment groups: conventional, active or passive self-ligating brackets, with an allocation ratio of 1:2:2. All subjects were treated using the same archwire sequence and space closing mechanics. Space closure was measured on models taken every 12 weeks throughout treatment. All measurements were taken by one operator, blinded to bracket type. RESULTS: A total of 98 patients were followed to completion. Data were analysed using linear mixed models and demonstrated no statistically significant difference between bracket types with respect to space closure. Therefore, the data were pooled to determine the effect of gender and FMPA on space closure. At all stages of space closure, there was a significant effect of gender (results are presented as effect size, lower and upper 95% confidence intervals and probability), that is passive [1.064, 0.521, 1.607, 0.001], active [0.825, 0.312, 1.339, 0.002] and total space closure [1.029, 0.527, 1.531, 0.001]. There was no statistically significant effect of FMPA on space closure. CONCLUSIONS: Space closure during fixed appliance therapy is affected by gender but is unaffected by FMPA.

A cross-sectional survey of 5-year-old children with non-syndromic unilateral cleft lip and palate: the Cleft Care UK study. Part 1: background and methodology.

OBJECTIVES: We describe the methodology for a major study investigating the impact of reconfigured cleft care in the United Kingdom (UK) 15 years after an initial survey, detailed in the Clinical Standards Advisory Group (CSAG) report in 1998, had informed government recommendations on centralization. SETTING AND SAMPLE POPULATION: This is a UK multicentre cross-sectional study of 5-year-olds born with non-syndromic unilateral cleft lip and palate. Children born between 1 April 2005 and 31 March 2007 were seen in cleft centre audit clinics. MATERIALS AND METHODS: Consent was obtained for the collection of routine clinical measures (speech recordings, hearing, photographs, models, oral health, psychosocial factors) and anthropometric measures (height, weight, head circumference). The methodology for each clinical measure followed those of the earlier survey as closely as possible. RESULTS: We identified 359 eligible children and recruited 268 (74.7%) to the study. Eleven separate records for each child were collected at the audit clinics. In total, 2666 (90.4%) were collected from a potential 2948 records. The response rates for the self-reported questionnaires, completed at home, were 52.6% for the Health and Lifestyle Questionnaire and 52.2% for the Satisfaction with Service Questionnaire. CONCLUSIONS: Response rates and measures were similar to those achieved in the previous survey. There are practical, administrative and methodological challenges in repeating cross-sectional surveys 15 years apart and producing comparable data.

Structural outcomes in the Cleft Care UK study. Part 2: dento-facial outcomes.

OBJECTIVES: To compare facial appearance and dento-alveolar relationship outcomes from the CSAG (1998) and CCUK (2013) studies. SETTING AND SAMPLE POPULATION: Five-year-olds born with non-syndromic unilateral cleft lip and palate. Those in the original CSAG were treated in a dispersed model of care with low-volume operators. Those in CCUK were treated in a more centralized, high-volume operator model. MATERIALS AND METHODS: We compared facial appearance using frontal view photographs (252 CCUK, 239 CSAG) and dental relationships using study models (198 CCUK, 223 CSAG). Facial appearance was scored by a panel of six assessors using a standardized and validated outcome tool. Dento-alveolar relationships were scored by two assessors using the 5-Year-Olds' Index. Ordinal regression was used to compare results between surveys. RESULTS: Excellent or good facial appearance was seen in 36.2% of CCUK compared with 31.9% in CSAG. In CCUK, 21.6% were rated as having poor or very poor facial appearance compared with 27.6% in CSAG. The percentage rated as having excellent or good dento-alveolar relationships was 53.0% in CCUK compared with 29.6% in CSAG. In CCUK, 19.2% were rated as having poor or very poor dento-alveolar relationships compared to 36.3% in CSAG. The odds ratios for improved outcome in CCUK compared to CSAG were 1.43 (95% CI 1.03, 1.97) for facial appearance and 2.29 (95% CI 1.47, 3.55) for dento-alveolar relationships. CONCLUSIONS: Facial and dento-alveolar outcomes were better in CCUK children compared to those in CSAG.

Functional outcomes in the Cleft Care UK study--Part 3: oral health and audiology.

OBJECTIVES: To compare oral health and hearing outcomes from the Clinical Standards Advisory Group (CSAG, 1998) and the Cleft Care UK (CCUK, 2013) studies. SETTING AND SAMPLE POPULATION: Two UK-based cross-sectional studies of 5-year-olds born with non-syndromic unilateral cleft lip and palate undertaken 15 years apart. CSAG children were treated in a dispersed model of care with low-volume operators. CCUK children were treated in a centralized, high volume operator system. MATERIALS AND METHODS: Oral health data were collected using a standardized proforma. Hearing was assessed using pure tone audiometry and middle ear status by otoscopy and tympanometry. ENT and hearing history were collected from medical notes and parental report. RESULTS: Oral health was assessed in 264 of 268 children (98.5%). The mean dmft was 2.3, 48% were caries free, and 44.7% had untreated caries. There was no evidence this had changed since the CSAG survey. Oral hygiene was generally good, 96% were enrolled with a dentist. Audiology was assessed in 227 of 268 children (84.7%). Forty-three per cent of children received at least one set of grommets--a 17.6% reduction compared to CSAG. Abnormal middle ear status was apparent in 50.7% of children. There was no change in hearing levels, but more children with hearing loss were managed with hearing aids. CONCLUSIONS: Outcomes for dental caries and hearing were no better in CCUK than in CSAG, although there was reduced use of grommets and increased use of hearing aids. The service specifications and recommendations should be scrutinized and implemented.

Centralization of cleft care in the UK. Part 6: a tale of two studies.

OBJECTIVES: We summarize and critique the methodology and outcomes from a substantial study which has investigated the impact of reconfigured cleft care in the United Kingdom (UK) 15 years after the UK government started to implement the centralization of cleft care in response to an earlier survey in 1998, the Clinical Standards Advisory Group (CSAG). SETTING AND SAMPLE POPULATION: A UK multicentre cross-sectional study of 5-year-olds born with non-syndromic unilateral cleft lip and palate. Data were collected from children born in the UK with a unilateral cleft lip and palate between 1 April 2005 and 31 March 2007. MATERIALS AND METHODS: We discuss and contextualize the outcomes from speech recordings, hearing, photographs, models, oral health and psychosocial factors in the current study. We refer to the earlier survey and other relevant studies. RESULTS: We present arguments for centralization of cleft care in healthcare systems, and we evidence this with improvements seen over a period of 15 years in the UK. We also make recommendations on how future audit and research may configure. CONCLUSIONS: Outcomes for children with a unilateral cleft lip and palate have improved after the introduction of a centralized multidisciplinary service, and other countries may benefit from this model. Predictors of early outcomes are still needed, and repeated cross-sectional studies, larger longitudinal studies and adequately powered trials are required to create a research-led evidence-based (centralized) service.

The impact of violence reduction initiatives on emergency department attendance.

BACKGROUND: Recent violence reduction initiatives in Glasgow have led to a reduction in recorded levels of violent crime.(1) This study evaluates the impact of these initiatives on assault-related emergency department attendances and admissions. METHODS: A retrospective observational study conducted in Glasgow Royal Infirmary's emergency department comparing assault-related emergency department attendances and hospital admissions over two 30-day study periods (April 2010 and April 2012). The primary outcome measure was the change in assault-related emergency department attendances. The secondary outcome measure was the impact on assault-related hospital and critical care admissions. RESULTS: In April 2010, there were 6098 emergency department attendances, 301 (4.9%) were due to assault. In April 2012, there were 7236 emergency department attendances, 263 (3.6%) were due to assault, representing a significant reduction in assault-related attendances (p < 0.01). There were significant reductions in level 1 admissions 2010 n = 56 (19.2%), 2012 n = 36 (14.0%) p = 0.04 and critical care admissions, 2010 n = 5 (1.7%), 2012 n = 1 (0.4%) p = 0.04. CONCLUSIONS: Violence reduction initiatives in Glasgow have contributed to a reduction in assault-related emergency department attendance at Glasgow Royal Infirmary. The reduction in hospital admissions, in particular critical care admissions, suggests a reduction in morbidity and cost to the National Health Service.

An introduction to dento-legal issues and risks in orthodontics.

Orthodontic treatment is not without risk. This article aims to look at some of the dento-legal issues surrounding orthodontic treatment, the risks to both the clinician and the patient, and how some of these risks can be mitigated.

Effect of a redesigned fracture management pathway and 'virtual' fracture clinic on ED performance.

OBJECTIVES: Collaboration between the orthopaedic and emergency medicine (ED) services has resulted in standardised treatment pathways, leaflet supported discharge and a virtual fracture clinic review. Patients with minor, stable fractures are discharged with no further follow-up arranged. We aimed to examine the time taken to assess and treat these patients in the ED along with the rate of unplanned reattendance. DESIGN: A retrospective study was undertaken that covered 1 year before the change and 1 year after. Prospectively collected administrative data from the electronic patient record system were analysed and compared before and after the change. SETTING: An ED and orthopaedic unit, serving a population of 300 000, in a publicly funded health system. PARTICIPANTS: 2840 patients treated with referral to a traditional fracture clinic and 3374 patients managed according to the newly redesigned protocol. OUTCOME MEASURES: Time for assessment and treatment of patients with orthopaedic injuries not requiring immediate operative management, and 7-day unplanned reattendance. RESULTS: Where plaster backslabs were replaced with removable splints, the consultation time was reduced. There was no change in treatment time for other injuries treated by the new discharge protocol. There was no increase in unplanned ED attendance, related to the injury, within 7 days (p=0.149). There was a decrease in patients reattending the ED due to a missed fracture clinic appointment. CONCLUSIONS: This process did not require any new time resources from the ED staff. This process brought significant benefits to the ED as treatment pathways were agreed. The pathway reduced unnecessary reattendance of patients at face-to-face fracture clinics for a review of stable, self-limiting injuries.

Microbial contamination of laboratory constructed removable orthodontic appliances.

OBJECTIVES: This study aims to determine whether laboratory constructed removable orthodontic appliances are free from microbial contamination prior to clinical use and to evaluate the dental hospital cross-infection procedures to ensure that patient-derived contamination does not enter the construction process, thereby propagating a cycle of cross-contamination. MATERIALS AND METHODS: The construction process of removable orthodontic appliances from three individuals was evaluated at every stage, from impression to final delivery of the appliance using molecular microbiological techniques. The bacterial profiles at each stage of appliance construction were obtained using denaturing gradient gel electrophoresis, along with the bacterial profiles of the three participants' saliva. This enabled the bacterial profiles found at each stage of construction to be compared directly with the saliva of the person for whom the appliance was being constructed. Bacteria were identified at each stage using 16S rDNA PCR amplification and sequence phylogeny. RESULTS: There was no evidence of bacterial cross-contamination from patients to the laboratory. The current process of disinfection of impression appears to be adequate. Contamination was found on the final removable appliances (0.97 × 10(2)-1.52 × 10(3) cfu ml(-1)), and this contamination occurred from within the laboratory itself. CONCLUSIONS: Every effort is made to reduce potential cross-infection to patients and dental professionals. Newly constructed removable appliances were shown not to be free from contamination with bacteria prior to clinical use, but this contamination is environmental. Further studies would be required to determine the level of risk this poses to patients. CLINICAL SIGNIFICANCE: Dental professionals have a duty of care to minimise or eradicate potential risks of cross-infection to patients and other members of the team. To date, much less attention has been paid to contamination from the orthodontic laboratory, so contamination and infection risks are unknown.

The effects of different orthodontic appliances upon microbial communities.

OBJECTIVES: Orthodontic appliances can promote accumulation of dental plaque, with associated enamel decalcification or gingival inflammation. The aim of this study was to examine longer-term microbiological changes during orthodontic treatment with fixed appliances. MATERIALS AND METHODS: Twenty-four orthodontic patients aged 11-14 years undergoing fixed appliance therapy were recruited into the study. Each was randomized for cross-mouth assignment of molar bands and bonded molar tubes to contralateral quadrants of the mouth. All patients received self-ligating brackets, but again using randomization, one upper lateral incisor bracket (left or right) also received an elastomeric ligature. Plaque samples from the molars and upper lateral incisors were obtained at intervals during treatment and up to 1 year after appliance removal. Denaturing gradient gel electrophoresis and 16S rDNA microarray were used to compare plaque microbial fingerprints. RESULTS: Plaque populations changed within 3 months of commencing treatment at all sites. The greatest differences in plaque composition were seen with self-ligating brackets with an elastomeric ligature. Post-treatment plaque associated with both types of molar attachment contained increased levels of periodontal pathogens Porphyromonas gingivalis, Tannerella forsythia, and Eubacterium nodatum, while Campylobacter rectus, Parvimonas micra, and Actinomyces odontolyticus were also elevated with bonds. CONCLUSIONS: The results suggest that orthodontic treatment may cause sustained changes in plaque microbiotas and that molar bond-associated plaque may have raised disease potential.

Assessment of a condition-specific quality-of-life measure for patients with developmentally absent teeth: validity and reliability testing.

OBJECTIVES: This article describes the process of validity and reliability testing of a condition-specific quality-of-life measure for patients with hypodontia presenting for orthodontic treatment. The development of the instrument is described in a previous article. SETTING AND SAMPLE POPULATION: Royal Devon and Exeter NHS Foundation Trust & Musgrove Park Hospital, Taunton. MATERIALS AND METHODS: The child perception questionnaire was used as a standard against which to test criterion validity. The Bland and Altman method was used to check agreement between the two questionnaires. Construct validity was tested using principal component analysis on the four sections of the questionnaire. Test-retest reliability was tested using intraclass correlation coefficient and Bland and Altman method. Cronbach's alpha was used to test internal consistency reliability. RESULTS: Overall the questionnaire showed good reliability, criterion and construct validity. This together with previous evidence of good face and content validity suggests that the instrument may prove useful in clinical practice and further research. CONCLUSIONS: This study has demonstrated that the newly developed condition-specific quality-of-life questionnaire is both valid and reliable for use in young patients with hypodontia.

Experiences of Wiki topic teaching in postgraduate orthodontics: what do the learners think?

INTRODUCTION: Traditionally, the academic content of many 3-year full-time postgraduate courses in orthodontics in the UK has been delivered using tutorial and lecture-based teaching. This is often teacher lead rather than learner centred. Even with the advent of teaching modules on the national virtual learning environment, although well liked by students, is still often teacher lead. An alternative on-line approach to learner-centred teaching is to use Wikis. MATERIALS AND METHODS: Nine postgraduate students in the first term of their full-time 3-year specialist training programme at Bristol Dental School were divided into three groups and wrote a Wiki on three interrelated topics. This process was repeated in the second term using three different, but still interrelated topics. Following each, they were asked to give detailed feedback on their Wiki topic teaching. RESULTS AND DISCUSSION: The results showed that students felt writing the Wikis was useful for team work, provided a more learner-centred approach, created a body of work in a live format that would be useful for revision and was a welcome variation on traditional teaching methods. The biggest problem encountered was the IT platform used to create the Wikis. The students also felt the Wikis should be assessed as a piece of group work rather than as separate individuals. CONCLUSIONS: Wiki topic teaching is a useful tool in the teaching of postgraduate orthodontics providing variation and a more learner-centred approach. Further exploration of the available IT platforms is required.

Three-dimensional digital models for rating dental arch relationships in unilateral cleft lip and palate.

Objective : To determine the reliability and reproducibility of using three-dimensional digital models as an alternative to plaster models for rating dental arch relationships in patients born with unilateral cleft lip and palate. Design : Reliability and reproducibility study. Methods : Study models of 45 patients born with unilateral cleft lip and palate were made available in plaster and three-dimensional digital models. Records were scored a week apart by three examiners using the 5-year-olds' index reference models in the same two formats as the patient models. To assess reproducibility the study was repeated 4 weeks later under similar conditions to minimize the influence of memory bias on the results. The reliability of using the three-dimensional digital models was determined by comparing the scores for each examiner with the plaster model scores. Results : Weighted kappa statistics indicated repeatability for the plaster models was very good (.83 to .87). For the three-dimensional digital models it was good to very good (.74 to .83). Overall, the use of the three-dimensional digital models showed good agreement with the plaster model scores on both occasions. Conclusion : Three-dimensional digital models appear to be a good alternative to plaster models for assessing dental arch relationships using the 5-year-olds' index.

Do I have enough time? The impact of recruiting patients to a randomised controlled trial at recruiting centres.

INTRODUCTION: This paper explores the impact of recruiting patients to a randomised controlled trial (RCT) at recruiting centres. This large multicentre RCT examining the efficacy of chewing gum compared to ibuprofen in the relief of orthodontic pain was carried out across nine recruiting centres. METHOD: The work diaries of clinicians and supporting staff at recruiting centres were analysed over a four-month period from September to December 2011. This quantified the amount of clinical and non-clinical time spent on research duties. RESULTS: Over this time period 98 patients were recruited across seven trial sites. On average, patient recruitment had a direct clinical impact of 19 minutes per patient recruited. The time commitment on trial administration outside the clinical sessions was much higher, averaging at 110 minutes per patient recruited, giving the overall time spent on the trial 129 minutes per patient. CONCLUSIONS: This information will be valuable to lead researchers when calculating the full economic cost of a proposed clinical trial and therefore when applying for grant funding. It may also be valuable to clinicians and their managers when considering becoming a principle investigator (PI) in a RCT. Although the impact on clinical time was 19 minutes per patient recruited, there is a considerably higher (almost six times greater) time commitment in administration around the recruitment of patients.

The 5-year-olds' Index: determining the optimal format for rating dental arch relationships in unilateral cleft lip and palate.

The aim of this investigation was to determine the optimal format for presenting the 5-year-olds' Index reference models for the assessment of dental arch relationships in unilateral cleft lip and palate (UCLP). The 5-year-olds' Index reference models were presented in four different formats: plaster models, coloured acrylic models, and two digital formats, which included three-dimensional digital models (3D), and black and white photographs. These formats were used to rate 45 plaster models of patients born with UCLP by a total of seven examiners comprising experienced and inexperienced examiners. Scoring was undertaken 1 week apart for each format with the patient models reassigned on each occasion to reduce the effect of memory bias. For intra-examiner agreement, the patient models were scored 3 weeks later under similar conditions by the same examiners. The reliability of using the different formats was determined using the plaster reference models as the 'gold' standard for comparison. Analysis of the results using weighted kappa (k) statistics showed the magnitude of agreement for all the formats of the 5-year-olds' Index were good to very good between examiners. The more experienced examiners were consistently more reliable in their scoring using the different formats. This study clearly demonstrated that 3D digital models of the 5-year-olds' Index could prove to be a promising alternative to physical models of the 5-year-olds' Index.

Time-dependent recontamination rates of sterilised dental instruments.

OBJECTIVES: To determine time-related recontamination rates of sterilised instruments, following guidance from the UK Department of Health (HTM 01-05) that such instruments within primary dental care may only be stored for 60 days following sterilisation using a vacuum autoclave. MATERIALS AND METHODS: A total of 25 used examination mirrors underwent a washer-disinfector cycle, individual packaging and finally vacuum autoclaving. Immediately after autoclaving, time zero, five mirrors were tested for microbial contamination by aerobic and anaerobic culture. At 31, 60, 90 and 124 days a further five mirrors were removed from their packaging and were similarly tested for microbial contamination. RESULTS: There was no bacterial growth on blood-enriched media under both aerobic and anaerobic conditions after 5 days of incubation at 37°C at any time period from 0 to 124 days post-sterilisation. CONCLUSIONS: There was no recontamination of sterilised instruments in this investigation over the test period of 124 days. This exceeds the recommended limit of 60 days stated by the UK Department of Health. The new guidance, HTM 01-05, appears to place an extra burden on primary care dentists. This burden is not without associated costs, and at present does not appear to be based on published evidence.