General dental practice is increasingly being recognised as the ideal situation for the conduct of clinical trials into the longevity of restorations. The aim of this study was to investigate the survival of 75 nanofilled resin composite restorations placed in an assortment of cavities using a self-etch dentine bonding agent, in five UK dental practices by members of the UK-based practice-based research group, the PREP Panel, with half of the restorations receiving a selective enamel etch and the other half being placed using a self-etching approach. The results indicated good performance of the restorations examined, with no failures being identified and excellent surface characteristics, in terms of colour stability, minimal surface roughness and optimal anatomic form, Selective enamel etching tended to produce less marginal discolouration, although these results were not statistically significant.

Visible light units (LCU) used in routine dentistry to cure light activated materials may become contaminated with oral micro-organisms. This pilot study was designed to investigate whether the fan, handle and base unit mains on/off button areas of three different designs of quartz tungsten halogen LCUs (3M Unitek 2500, Elipar Highlight, Demetron Optilux 401) were effectively disinfected after use in a dental teaching hospital. Over a period of seven days 52 LCUs were swabbed before clinics in the morning and 28 were swabbed again after clinics in the afternoon. Bacterial contamination was detected on approximately 40% (20/52) of units before use and 64% (18/28) after use: few viable organisms were detected on the fan or handle areas, but many were isolated from the mains button, including Staphylococus aureus. These findings highlight the need for greater awareness of the potential risk of contamination of the base unit and compliance with recommendations to clean and disinfect all areas of the units.

In response to timings from readers and greater editorial content by increasing the number of pages, Dental Update will, from January 2007, offer 4 hours of verifiable CPD rather than the 2.5 hours previously given.

Objectives. Differences in mechanical and physical properties exhibited by novel low-shrink resin-based composite (RBC) formulations compared with conventional methacrylate RBCs may contribute to the clinical success of the candidate material. The aim of the current study was to investigate the effect of water uptake characteristics and water solubility on the mechanical properties of two methacrylate (Z100 and Filtek (TM) Z250), an experimental oxirane (OXI) and silorane (SIL) RBC following short- and medium-term immersion.Methods. The water sorption/solubility and associated diffusion coefficients of each material (n = 5) were measured using gravimetric analysis following short- (0.1, 0.5, 1, 4, 24 and 48 h) and medium-term (1, 4, 12 and 26w) immersion. The bi-axial flexure strength, associated Weibull moduli (n=20) and fracture analysis using scanning electron microscopy (SEM) of each material for similar immersion periods was also investigated.Results. Following 0.5 h and each subsequent short- and medium-term immersion period the water sorption of Z100 and Filtek (TM) Z250 was decreased compared with OXI. A significant decrease in bi-axial flexure strength and associated increase in filter particle exfoliation identified through SEM, was identified for OXI compared with Z100, Filtek (TM) Z250 and SIL following 26w immersion. SIL exhibited the significantly lowest water sorption, solubility and associated diffusion coefficient following each immersion period.Significance. The increase in water sorption, solubility and the associated diffusion coefficient of the experimental oxirane RBC, OXI was manifested as a significant decrease in bi-axial flexure strength and attributed to the decrease in synergy between the filter particles and resin matrix. The decreased water sorption, solubility and associated diffusion coefficient of the experimental silorane RBC, SIL may potentially improve hydrolytic stability of RBC restorations demonstrated by the non-significant decrease in bi-axial flexure strength following medium-term immersion. (c) 2005 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Aim: It is the purpose of this paper to investigate the outcome of direct-placement restorations provided within the General Dental Services in England and Wales, and to identify the patient factors which may affect this using a database derived from patient treatment data at the Dental Practice Board.Methods: For this work, survival of a restoration was considered to be the time between the date of completion of the course of treatment in which it was placed and the date of acceptance of the course of treatment when the next tooth-specific treatment was carried out on the same tooth. A modified version of Kaplan-Meier statistical methodology was used to plot survival curves for restorations in different subgroups of patients within the population of patients for whom data were available.Results: The results indicated that patients' gender was of little significance in the tong-term survival of restorations, but patient age had a significant effect, with the restorations of older patients surviving less well than those of younger patients (P < 0.001). The charge-paying status of the patient had a statistically significant but small effect (P < 0.001), with survival for charge-payers being slightly higher throughout the observation period. There was a strong relationship between attendance frequency and survival time, with restorations of more frequent attenders performing less well than those of less frequent attenders; (P < 0.001).Conclusions: Patient factors such as age, charge-paying status, interval between courses of treatment, continuity of care by one dentist, and annual gross fees incurred, have all been found to influence the survival of directly placed restorations. (C) 2005 Elsevier Ltd. All rights reserved.

Objectives. Frictional forces play a major rote in the oral wear process of dental resin-based composites (RBCs) and it would be of interest to consider how the energy from friction is dissipated at the material surface. Consequently, the micromechanical wear properties of conventional methacrylate compared with novel oxirane RBCs were assessed.Method. The frictional coefficient (p), volume loss and Vickers hardness number (VHN) of oxirane (EXL596 and H1) and methacrylate RBCs (Z100 and Fittek(TM) Z250) were evaluated. Archard's wear equation was implemented to obtain the wear coefficient (K) and expressed as a 'fraction of friction' (K/mu) to indicate the dissipation of frictional energy that resulted in wear. Scanning electron microscopy (SEM) was used to qualitatively asses the wear facets of each RBC following 50000-cycles.Results. The mean frictional coefficients observed between the oxirane and methacrylate RBCs were not significantly different (P> 0.05). However, the volume toss of EXL596 and H1 (5.9 +/- 0.4 and 4.7 +/- 0.3 X 10(-2) mm(3)) was significantly increased compared with Z100 and Filtek(TM) Z250 (1.7+/-0.2 and 2.3+/-0.3 X 10(-2) mm(3)). The VHN of EXL596 and H1 was either significantly greater (P = 0.021) or similar (P=0.089) to Filtek(TM) Z250, respectively. An increase in K/mu was reported for EXL596 and H1 (34.7+/-4.1 and 22.8+/-2.4x10(-4)) compared with Z100 and Filtek(TM) Z250 (8.50 +/- 0.7 x 10(-4) and 8.62+/-1.0x10(-4)) (P<0.05). SEM images of the oxirane RBCs exhibited increased surface fatigue and delamination of the surface layers compared with the methacrylate RBC specimens following 50,000-cycles.Conclusion. The significant decrease in wear resistance of the oxirane compared with methacrylate RBCs was unexpected since frictional coefficients and/or surface hardness were statistically similar. The decreased wear resistance of EXL596 and H1 compared with Z100 and Filtek(TM) Z250 was further explained by the increase in K/mu from wear theory and the associated increase in surface fatigue identified from SEM. The simplistic testing procedure combined with SEM utilized in the current investigation provided a greater insight into the wear mechanism by considering the effect of frictional energy at the specimen surface which may benefit the development of improved wear resistance for experimental RBC materials. (C) 2005 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Aim: It is the aim of this paper to consider the dental factors associated with the need for re-intervention on a restoration, such as the tooth position, size of cavity, and restoration material.Methods: Patients whose data were included in this study were those whose birthdays were included within a set of randomly selected dates, one of which was chosen in each possible year of birth. The restoration records consisted of all those records containing directly placed restorations which related to courses of treatment of patients 18 years or older with last date on the claim form after 31st December 1990, and with date of acceptance after September 1990 and before January 2002. For each tooth treated with a direct restoration the subsequent history of intervention on that tooth was consulted, and the next date of intervention, if any could be found in the extended data set, was obtained. Thus a data set was created of direct restorations with their dates of placement and their dates, if any, of re-intervention.Results: Data for over 80,000 different adult patients were analyzed, of whom 46% were mate and 54% female. A total of 503,965 tooth restoration occasions were obtained from the data over a period of eleven years.Single surface amalgam restorations were found to have the longest survival - 58% at 10 years, and glass ionomer the shortest 38% at 10 years. Factors which were found to reduce restoration outcome included involvement of the incisal angle in composite restorations-this resulted in a reduction in median survival of around two years-and the placement of pins in a restoration. The presence of a root filling was also found to reduce the survival of restorations in the crown of the root filled tooth.Conclusions: Small amalgam restorations have longer survival times before re-intervention than large amalgam restorations such as MOD. Composite and glass ionomer restorations perform less well than amalgam restorations. Pin placement and root fitting reduce the survival time of restorations. (C) 2005 Published by Elsevier Ltd.

All-ceramic crowns offer the potential for increased esthetics compared with metal-ceramic crowns. Dental ceramics employed for ail-ceramic restorations also resist wear extremely well and do not elicit a pulpal response from vital teeth as is common with some nonprecious alloys used for metal-ceramic crown reconstruction. It can be seen from both laboratory testing data on the influence of cement type on specimen longevity and clinical studies on the failure rates of conventionally and adhesively luted crowns that when the placement procedure incorporates a dentin bonding step, enhanced survival rates are recorded. The laboratory fracture studies comparing restorations luted conventionally and adhesively, combined with the clinical and laboratory studies examining the strengthening of ceramics by the application of an adhesive lute compared with a conventional acid-base lute, would possibly preclude the use of nonadhesive technologies to support dental ceramics.

Aim: It is aim of this paper to investigate the outcome of direct-placement restorations provided within the General Dental Services in England and Wales, in relation to the factors related to time and place of restoration placement. Methods: A modified version of Kaplan–Meier statistical methodology was used to plot survival curves for restorations placed at different times and places, within the population of patients for whom data were available. Results: The results indicated that overall, restoration survival time to re-intervention has declined over the last decade, but that most of the decline can be accounted for by the change in the relative numbers of amalgam and other direct restorations. Restoration survival to re-intervention is independent of whether the water is fluoridated in the area of the dentist's surgery address. Variation with region is not great, but restorations placed in Wales survived to re-intervention significantly longer than those in England (P<0.0001). Conclusions: Overall, there was some evidence of a reduction in survival times with time. Restorations placed in Wales survived longer to re-intervention than restorations placed in England. Restoration survival was not dependent on whether the dentist who placed the restoration practised in an area in which the water was fluoridated. Performance of amalgam restorations was not found to have altered significantly with time, but performance of composite and glass ionomer deteriorated with time.

Objectives: The development of novel low-shrink resin-based composites (RBCs) may offer a potential reduction in potymerisation shrinkage stresses generated at the tooth/restoration interface compared with current methacrylate RBCs. In vitro cuspal deflection and microleakage of meiso-occlusal-distat (MOD) cavities restored with experimental oxirane and silorane (EXL596 and H1) and methacrylate (Z100 and Filtek (TM) Z250) RBCs were assessed.Methods: Standardised pre-molar MOD cavities were prepared (n=10) and restored with each material. The flexure of buccal and palatal cusps was recorded 0.1 h following irradiation utilising a differential transformer deflection gauge. Each restored tooth was subjected to a thermocycling regime and microleakage of tooth sections were assessed following 24 h immersion in 0.2% fuschin dye. The degree of conversion (DC) of each RBC material was also assessed using Fourier transform infrared (FTIR) spectroscopy following 0.1, 0.5, 1, 4, 24 and 48 h post-irradiation.Results: A total cuspal deflection was observed for EXL596 (2.5 +/- 0.9 mu m) and H1 (6.0 +/- 1.8 mu m) compared with Z100 (20.0 +/- 4.7 mu m) and Filtek (TM) Z250 (16.5 +/- 3.3 mu m) following 0.1 h. The cavities restored with EXL596 displayed significantly higher microleakage than any other RBC and H1 exhibited non-significant and significantly decreased microleakage compared with Z100 and Filtek (TM) Z250, respectively. The DC of EXL596 and H1 was significantly decreased compared with Z100 and Filtek (TM) Z250 following 0.1, 0.5 and 1 h.Significance: The 'living' potymerisation associated with the novel oxirane and silorane RBCs and the associated decrease in cuspal deflection may suggest a decrease in the magnitude of potymerisation shrinkage stress at the tooth/ restoration interface. The decreased DC following 0.1 h of the oxirane compared with the methacrylate RBCs has provided information on the cure rate of cationic and free-radical polymerisation mechanisms, respectively. The inadequate marginal seat of cavities restored with EXL596 would preclude its use as a dental restorative. The reduction in cuspal deflection and decrease in microleakage of cavities restored with H1 compared with Filtek (TM) Z250 may be advantageous in terms of marginal integrity following placement. However, the non-significant difference in microleakage between the H1 and Z100 may only present modest decreases in the deleterious effects of shrinkage stress. (c) 2004 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Aim: It is the aim of this paper to investigate the survival of direct-placement restorations provided within the General Dental Services in England and Wales, in relation to the dentist factors which may affect this.Methods: For this work, survival of a restoration was considered to be the time between the date of completion of the course of treatment in which it was placed and the date of acceptance of the course of treatment when the next tooth-specific treatment was carried out on the same tooth. A modified version of Kaplan-Meier statistical methodology was used to plot survival curves for restorations placed by different subgroups of dentists.Results: The age and experience of the dentist who placed the original restoration were found to be related to restoration survival, with older dentists having shorter intervals from placement of restorations to re-intervention (P < 0.001). Country of qualification seems not to be relevant within Europe in terms of restoration survival, but dentists who qualified outside Europe achieve different restoration survival times for the restorations that they place. Dentist's gender has no relationship with time from restoration to re-intervention.Conclusions: Dentist factors such as age, country of qualification, and employment status, but not the gender of the dentist, have been found to influence the survival of directly placed restorations. (C) 2005 Published by Elsevier Ltd.

Objectives. To investigate the effect of polymerisation shrinkage stress of various aesthetic posterior fitting materials on cuspal movement and cervical gingival microleakage of mesio-occlusal-distal (MOD) restorations placed in increments in extracted maxillary premolar teeth.Methods. Forty sound extracted upper premolar teeth were subjected to standardised preparation of a large MOD cavity. One curing regimen was used and each posterior fitting material was placed in eight increments with the appropriate bonding system. A twin channel deflection-measuring gauge allowed a measurement of individual cusp deflections at each stage of polymerisation. Restored teeth were thermocycled before immersion in 0.2% basic fuchsin dye for 24 h. After sagittal sectioning of the restored teeth in a mesio-distal plane, the sectioned restorations were examined to assess cervical gingival microleakage.Results. In general, cuspal deflection measurements were dependent upon the constituent monomers and the associated shrinkage on curing, with significantly increased cuspal. movement (P<0.05) being recorded for Z100 (20.03 +/- 2.92 mum) compared with Filtek Z250(TM) (12.34 +/- 2.18 mum), P60 (13.41 +/- 4.43 mum) and Admira (11.2 +/- 2.58 mum). No significant differences were identified between the posterior fitting materials when the cervical gingival microleakage scores were examined.Conclusions. It would appear that a reduction in the manufacturers' reported volumetric polymerisation shrinkage for Z100 (4.0%) to below 3% for Fittek Z250(TM), P60 and Admira, resulted in a significant reduction in the associated cuspal strain on the MOD cavity. The diluent triethyleneglycol dimethacrylate (TEGDMA) increases the polymerisation shrinkage of Z100 resin-based composite due to an increased concentration of carbon-to-carbon double bonds (C=C). The replacement of TEGDMA with urethane dimethacrylate (UDMA) and Bis-EMA in Filtek Z250(TM) and P60, decreases the polymerisation shrinkage stress by increasing the cross-linking of polymer networks. However, no group was identified as producing less gingival microleakage at the cervical dentine cavosurface margin when the cavities were sectioned and examined, regardless of the reported variations in cuspal strain and the associated volumetric polymerisation shrinkage values. (C) 2004 Elsevier Ltd. All rights reserved.

BACKGROUND:This study aimed to determine the reasons for dentists' choice of materials, in particular amalgam and resin composite, in Australia.METHOD:A questionnaire was developed to elicit this information. The names and addresses of 1000 dentists in Australia were selected at random. The questionnaire was mailed to these dentists with an explanatory letter and reply-paid envelope.RESULTS:A total of 560 replies were received. Regarding choice of material, 99 per cent of respondents cited clinical indication as an influencing factor, although patients' aesthetic demands (99 per cent of respondents), patients' wish (96 per cent), patients' financial situation (82 per cent), and lecturers' suggestions (72 per cent) were also reported to influence respondents' choice of materials. Twelve per cent of respondents used composite 'always', 29 per cent 'often', 32 per cent 'sometimes', 23 per cent 'seldom' and 4 per cent 'never' in extensive load-bearing cavities in molar teeth. For composite restorations in posterior teeth, 84 per cent 'always', 'often' or 'sometimes' used the total etch technique, 84 per cent used a thick glass-ionomer layer and 36 per cent never used rubber dam. Fifty-nine per cent of respondents reported a decreased use of amalgam over the previous five years. Sixty-eight per cent of respondents agreed with the statement 'discontinuation of amalgam restricts a dentist's ability to adequately treat patients'. Seventy-five per cent considered that the growth in the use of composites increased the total cost of oral health care.CONCLUSIONS:Of the respondents from Australia 73 per cent place large composite restorations in molar teeth and their choice of material is influenced greatly by clinical indications, and patients' aesthetic demands.

AIMS:To assess by postal questionnaire, cross-infection control methods, especially sterilisation procedures, of 700 general dental practitioners in the Republic of Ireland, and to biologically monitor steam pressure sterilisers or autoclaves in their practices.MAIN OUTCOME MEASURES:Methods of instrument cleaning and sterilisation, autoclave efficacy.RESULTS:A response rate of 40% with all, except one practitioner, using steam sterilisation. 49% also reported the use of chemical sterilisation with a quarter of these using glutaraldehyde. However, instrument soaking time varied greatly from 2.5 minutes to 74 hours. Methods of instrument cleaning prior to autoclaving were as follows: scrubbing by hand 41.5%, ultrasonic cleaning 7.0%, combination of both 50%. 52.9% of the respondents did not autoclave their dental handpieces and only 44.7% disinfected impressions before sending them to the laboratory. The autoclaves of thirty practitioners (11.3%) did not pass the initial biological test. Following counselling about possible causes of failure, four autoclaves (1.5%) failed a repeat biological test. However, seven practitioners did not return the repeat biological test.CONCLUSIONS:Some aspects of recommended cross-infection control procedures are well adhered to, e.g. instrument cleaning, but further education is required in certain key areas, in particular the use of chemical sterilisation, dental handpiece autoclaving and impression disinfection. There is also a need to increase awareness of the importance of routine autoclave servicing and calibration, along with validation and monitoring.

Patient demand for esthetics has increased globally, and often for reasons of patient self-esteem. However, important ethical issues encompass treatment for purely esthetic reasons. Also, perceptions of what is esthetic differ among patients and clinicians. Therefore, the aim of this article is to make suggestions regarding some of the issues surrounding the ethical, esthetic treatment of patients, as well as present three cases illustrating the different meanings of esthetic health to different people.

AIM The objective of this study was to measure the microbial contamination released from dental unit air lines (DUAL) and dental unit water lines (DUWL). MATERIALS AND METHODS Emissions from DUAL and DUWL from five dental units supplied by a central water source (tap) and a centralised air supply were sampled three times over a five- week period. Air was forced through sterile water and then plated onto selective agar using apparatus designed to spread the sample solution evenly, and then incubated at room temperature for seven days. Colonies were then counted and the concentration of bacteria present was determined and expressed as colony forming units per millilitre (cfu/ml) per minute. The same procedure was used to evaluate five other dental units, which had attached independent water reservoir (bottle) systems (IWR). Only deionised water was added to the bottles and unit waterlines were cleaned weekly with alkaline peroxide based solution. Values were expressed as cfu/ml. RESULTS Air and water specimens obtained from dental units supplied with tap water had microbial counts significantly (t-test, p < 0.05) greater than IWR dental units. CONCLUSIONS Results indicate that IWR can reduce the numbers of micro-organisms released from DUWL. However, the effectiveness of such systems should be routinely monitored. Emissions from DUAL seems to reflect the levels of microbial contamination present in DUWL.

OBJECTIVE:Packable composites are a comparatively recent addition to the dentist's armamentarium, Solitaire-2 being an example of this type of material. This paper reports the performance of 100 restorations formed in Solitaire-2 in conjunction with the Gluma Solid Bond system and Gluma One Bond bonding systems, in Class I and II cavity restorations in permanent teeth, placed in the practices of five members of the Product Research and Evaluation by Practitioners (PREP) Panel, a group of United Kingdom-based dental practitioners who are prepared to undertake research projects in their practices. METHOD AND MATERIALS:Five members of the PREP Panel were each requested to place 20 Solitaire-2 restorations. These restorations were reviewed at 1 year by a trained and calibrated evaluator, and the PREP panel member who had placed the restorations. RESULTS:A total of 88 restorations (33 Class I, 55 Class II) in 49 patients (mean age 43 years) were reviewed at 1 year. One Class II restoration (a large mesio-occlusodistal restoration) had been replaced at 10 months after a fracture was detected across the distal box. The remaining 87 (99%) of the restorations were intact with no secondary caries detected. CONCLUSION:Ninety-nine percent of the Solitaire-2 restorations, placed in general dental practice conditions in conjunction with the Gluma Solid Bond system and Gluma One Bond bonding systems, were found to be performing satisfactorily at 1 year.