New frontiers in Dental Technology: An Overview.

The pace of technological advance across science is staggeringly fast. Our ability to translate some of the potential developments in technology into concepts/products/devices that can assist dentists in caring for patients is key to ensuring that both the profession and the people we care for derive full benefit from these new technologies. This overview will focus in four areas: research and how we gather and interpret data to inform health care; the diagnosis and prevention of disease; planning care; and new concepts in terms of achieving desired health outcomes for patients. Some of the technological advances will be in their infancy and others close to or indeed clinical reality. The objective of this overview is to show where we are in terms of the cutting edge of technology and to whet the appetite for things to come.

Oral hygiene of hospitalised older patients with lower limb fracture.

INTRODUCTION: good oral hygiene is important for eating, talking and improved quality of life, and is part of basic patient care, but there are few observational studies in hospitalised older patients. The aim of this study is to investigate dental plaque load in older patients over time in hospital. METHODS: we examined the mouths of 93 patients with lower limb fracture prospectively at day 1, 7 and 14 after admission in a Newcastle upon Tyne Hospital. We assessed dental and denture plaque load, dry mouth symptoms and tooth number, along with demographic and frailty variables. We used univariate generalised linear modelling and mixed effects models to investigate associations between increased plaque and patient characteristics. RESULTS: in dentate patients, plaque score increased with time in hospital (P = 0.007, odds ratio (OR): 1.02; 95% confidence of interval (CI): 1.01-1.04). Frailty (P = 0.015, OR: 1.19; 95% CI: 1.04-1.37), dementia (P < 0.001, OR: 4.30; 95% CI: 2.03-9.12), residence in an institution (P < 0.001, OR: 4.61; 95% CI: 2.18-9.74), decreased mobility (P = 0.013, OR: 0.97; 95% CI: 0.96-0.99), but not Charlson comorbidity index (P = 0.102, OR: 1.08; 95% CI: 0.99-1.19), were associated with increased plaque scores at every time point. CONCLUSIONS: oral hygiene deteriorated in dentate patients in hospital. Plaque scores were significantly higher in patients who were more likely to be dependent on others for their oral hygiene.

Factors affecting patient valuations of caries prevention: Using and validating the willingness to pay method.

OBJECTIVES: Determining the value of, or strength of preference for health care interventions is useful for policy makers in planning health care services. Willingness to pay (WTP) is an established economic technique to determine the strength of preferences for interventions by eliciting monetary valuations from individuals in hypothetical situations. The objective of this study was to elicit WTP values for a dental preventive intervention and to analyze the factors affecting these as well as investigating the validity of the WTP method. METHODS: Patients aged 40 years plus attending dental practices in the UK and Germany were recruited on a consecutive basis over one month. Participants received information about a novel root caries prevention intervention. They then completed a questionnaire including a WTP task. Where the coating was indicated, patients were offered this for a payment and acceptance was recorded. Analysis included econometric modelling and comparison of expected (based on stated WTP) versus actual behaviour. RESULTS: The mean WTP for the coating was £96.41 (standard deviation 60.61). Econometric models showed that no demographic or dental history factors were significant predictors of WTP. 63% of the sample behaved as expected when using stated WTP to predict whether they would buy the coating. The remainder were split almost equally between those expected to pay but who did not and those who were expected to refuse but paid. CONCLUSIONS: Values for a caries preventive intervention had a large and unpredictable variance. In comparing hypothetical versus real preferences both under- and over-valuation occurs. CLINICAL SIGNIFICANCE: Wide and unpredictable variation in valuations for prevention may mean that there are difficult policy questions around what resource should be allocated to dental prevention and how to target this resource.

Dental and microbiological risk factors for hospital-acquired pneumonia in non-ventilated older patients.

METHODS: We obtained a time series of tongue/throat swabs from 90 patients with lower limb fracture, aged 65-101 in a general hospital in the North East of England between April 2009-July 2010. We used novel real-time multiplex PCR assays to detect S. aureus, MRSA, E. coli, P. aeruginosa, S. pneumoniae, H. influenza and Acinetobacter spp. We collected data on dental/denture plaque (modified Quigley-Hein index) and outcomes of clinician-diagnosed HAP. RESULTS: The crude incidence of HAP was 10% (n = 90), with mortality of 80% at 90 days post discharge. 50% of cases occurred within the first 25 days. HAP was not associated with being dentate, tooth number, or heavy dental/denture plaque. HAP was associated with prior oral carriage with E. coli/S. aureus/P.aeruginosa/MRSA (p = 0.002, OR 9.48 95% CI 2.28-38.78). The incidence of HAP in those with carriage was 35% (4% without), with relative risk 6.44 (95% CI 2.04-20.34, p = 0.002). HAP was associated with increased length of stay (Fishers exact test, p=0.01), with mean 30 excess days (range -11.5-115). Target organisms were first detected within 72 hours of admission in 90% participants, but HAP was significantly associated with S. aureus/MRSA/P. aeruginosa/E. coli being detected at days 5 (OR 4.39, 95%CI1.73-11.16) or 14 (OR 6.69, 95%CI 2.40-18.60). CONCLUSIONS: Patients with lower limb fracture who were colonised orally with E. coli/ S. aureus/MRSA/P. aeruginosa after 5 days in hospital were at significantly greater risk of HAP (p = 0.002).

Use of micro-Raman spectroscopy to investigate hybrid layer quality in demineralized root dentine.

Treatment of early root caries using resin adhesives to stabilize demineralized dentine and deprive bacteria of nutrients is a recognized and conservative treatment option. Essential to its success is a stable resin-dentine interface, with effective infiltration of demineralized dentine and adequate resin curing. The objective of this study was therefore to examine degree of cure (DoC) and depth of penetration of dentine adhesives in demineralized dentine using micro-Raman spectroscopy. Three commercially available adhesives were applied essentially according to manufacturers' instructions to visibly wet demineralized dentine, with two coats of primer to reduce dilution. Specimens were sectioned perpendicular to the bonded interface and micro-Raman spectroscopy performed on the cross section. Molecules associated with the adhesive were detected to depths greater than 100 µm indicating a thicker hybrid layer than seen in sound dentine. The hybrid layer showed an increase in proportion of aliphatic C=C double bonds at the base of the hybrid layer, which may be a consequence of reduced DoC or phase separation. Micro-Raman spectra suggest deep zones contain an increased concentration of HEMA and a lower concentration of BisGMA, which is likely to be less stable and may contribute to early breakdown of the dentine adhesive interface.

Cantilever FPDs have lower success rates than end abutted FPDs after 10-years of follow-up.

SELECTION CRITERIA: Studies were located using a MEDLINE search strategy for English-language articles published from 1966 to 2004. A systematic review of 13 studies of cohort design (no randomized control trials were available) with the majority being retrospective. Seven hundred subjects with an age range of 26 to 84-years with a total of 816 FPDs with cantilever extensions were selected. The mean number of cantilever extensions varied from 1 to 6. Prostheses were of mixed design with 72% gold/acrylic structures. There are no data on the number of abutments compared with pontics or the overall length of the prostheses in this analysis KEY STUDY FACTOR: Longitudinal follow-up of cantilever FPDs to failure or complication. All studies were required to have a mean minimum follow-up time of 5 years. MAIN OUTCOME MEASURE: Time to survival of the restorations, with secondary outcome measures of proportion of restoration successful at 10 years (success was defined as survival with no biological or mechanical complications) and time to biological (caries, loss of vitality and periodontal disease) and technical (loss of retention, abutment fracture, superstructure fracture) complication. MAIN RESULTS: The estimated aggregate proportion of cantilever FPDs surviving at 10 years was 81.8% (95% CI: 78.2-84.9%), with an annualized failure rate of 2 per 100 FPDs (95% CI: 1.63%-2.46%). Failure was not influenced by the number of cantilevered pontics or the material used for bridge construction in these data. The estimated aggregate proportion of cantilever FPDs successful (free of all complications) at 10 years was 63% (95% CI: 54.7%-70.2%). The estimated aggregate proportion with caries at one or more abutment teeth at 10 years was 9.1% (95% CI: 6.3%-13%). The estimated aggregate proportion with loss of vitality of one or more abutment teeth at 10 years was 32.6% (95% CI: 13.9%-64.9%). Rates of loss of vitality were much higher in the studies using extensive (12-unit FPDs supported by 2 cuspids) mandibular prostheses than those with shorter extensions. The estimated aggregate proportion with progression of periodontal disease leading to loss of the FPD at 10 years was 1% (95% CI: 0.3%-3%).The estimated aggregate proportion with loss of retention of the FPD at 10 years was 16.1% (95% CI: 8.8%-28.4%). Rates of loss of retention were much higher in the studies using extensive (12-unit FPDs supported by 2 cuspids) mandibular prostheses than those with shorter extensions. The estimated aggregate proportion with fracture of abutment teeth at 10 years was 2.4% (95% CI: 0.6%-9.8%). The estimated aggregate proportion with framework, veneer, or core fractures at 10 years was 5.9% (95% CI: 3.3%-10.4%). CONCLUSIONS: Estimated survival and success rates of cantilever FPDs were lower than previously reported rates for typical end-abutement supported FPDs; a 10-year failure rate of 18.2% had previously been reported for end-abutment supported FPDs for comparison.

Changes in oral health over a 10-yr period in Switzerland.

The Swiss Health Surveys are conducted every 5 yr, and alternate surveys contain information on oral health. Worldwide the population is ageing and oral health is improving. The aim of this study was to identify if these trends are continuing in a relatively affluent society with low levels of edentulousness. Participants in the 1992 and 2002 surveys completed a written questionnaire including items on oral health (response rates 75% and 86% respectively). Data were weighted and bivariate analyses were performed to calculate the average number of missing teeth and the prevalence of different prosthetic dental restorations for each cohort. Over the 10-yr period the proportion of subjects retaining all natural teeth increased, and the mean number of teeth increased, on average, by 1.3. Among those who required prosthetic dental restorations, fixed restorations increased and complete denture use was reduced. Strikingly, 4.4% of this sample reported having oral implants in 2002. Greater numbers of missing teeth and a higher prevalence of use of removable prostheses were still seen in women, in those who had only completed compulsory education, in subjects from families with low income, in those who smoke, and in those who were overweight, in 2002.

Bonding of adhesive resin luting agents to metal and amalgam.

The shear bond strength of three adhesives, Panavia 21, Superbond, All Bond C&B Cement, and a dual cure resin (Variolink), to Ni-Cr-Be (Rexillium III), Midigold (Type III gold) and Amalgam (Sybraloy) were determined. Fifteen samples were prepared using 800 grit abrasive papers for Ni-Cr and Midi-Gold, and 100 grit papers for amalgam. Ni-Cr-Be and Midi-Gold samples were sandblasted for 30 s and steam cleaned for 10 s. The adhesives were bonded to the samples using gelatine capsules and were matured for 24 h in water at 37 degrees C. The samples were debonded in shear using an Instron at a cross-head speed of 1 mm/min. The data was analysed using ANOVA and a Tukey test. The bond strength of Superbond to both metal alloys was significantly higher (P<0.05) than any of the materials tested, with the exception Panavia 21 to gold. The bond strength of All Bond C&B cement had shown to be not significant difference from those of Panavia 21 and Variolink, when bonded to Rexillium and Midi-Gold, respectively. The bond strength of All Bond C&B Cement to amalgam was significantly greater (P<0.05) than those of the other materials tested. The shear bond strength to gold showed lower bonding for all adhesives when compared with Rexillium (P<.001). The ranking of bond strength to both alloys was as follows: Superbond>Panavia 21>All Bond C&B>Variolink. The nature of substrate to be used for bonding and the adhesive material itself are important factors in bonding which can be achieved between cast metals and prepared teeth with amalgam filling. Superbond should be successful as an adhesive for the attachment of all substrates tested, with the possible exception of amalgam, for which All Bond C&B Cement gives the best result.

Bonding of crown and bridge adhesive resins to dentine.

The shear bond strength of three adhesives, Panavia 21, Superbond, All Bond C&B Cement, and Variolink (a dual cure resin) to various dentine depths were determined. Fifteen human fully erupted permanent first and second molars were wet ground using 500 and then 800 grit abrasive papers to expose the superficial, middle and the deep dentine, for each adhesive tested. Five samples were prepared for each dentine depth. The adhesives were bonded to the samples using gelatine capsules and were matured for 24 h in water at 37 degrees C. The samples were debonded in shear using tensile testing machine at a cross-head speed of 1 mm/min. The data were analysed using ANOVA and the Tukey test. The fracture surfaces were examined by optical microscopy. The bond strength of Superbond to dentine was significantly higher (P<0.05) than any of the materials tested. The bond strength of all materials tested was shown to be affected by dentine depth, except for Superbond. Fractured dentine specimens showed that the samples of Superbond are almost cohesive (>90%), and the samples of other adhesives are mostly adhesive (>70%). These results confirm that Superbond is capable of forming a bond at various dentine depths.

What dentition assures oral function?

OBJECTIVE: To evaluate the relationship between dentition and oral function. MATERIAL AND METHODS: A search of the English literature was undertaken using PubMed and appropriate keywords. Citations were identified and hand sorted to confirm their validity against our inclusion criteria. Four specific areas of oral function were addressed; (I) masticatory function, (II) aesthetics, satisfaction and psychosocial ability, (III) occlusal support and stability and (IV) other functionality including tactile perception, phonetics and taste. RESULTS: From an initial pool of 1460 citations, 83 articles met the inclusion criteria. These were summarized and relevant data extracted for incorporation into the review. Masticatory efficiency (assessed as comminution efficiency) and masticatory ability (self-reported) are both linked to the number of teeth. A minimum of 20 teeth with nine to 10 pairs of contacting units (including anterior teeth) is associated with adequate efficiency and ability. Tooth numbers below that level yield impaired masticatory efficiency and are likely to result in reduction in reported masticatory ability. Aesthetics and satisfaction are markedly impaired with loss of anterior teeth. Satisfaction is most likely to be achieved in people who also retain a premolar dentition. Further, there is little increase in satisfaction seen in subjects who retained molar teeth. However, there are marked variations in subjective measures of aesthetics and psychosocial comfort between age groups, social classes, cultures, regions and countries. For most people, occlusal support and stability are obtained with three to four functional posterior units with a symmetrical pattern of tooth loss or five to six units with an asymmetrical pattern. There was no relationship between occlusal factors and symptoms of temporomandibular dysfunction. Phonetics may be maintained even with large anterior restorations. Patients generally attribute a low significance to phonetics, tactile perception and taste compared with mastication and appearance. CONCLUSIONS: The World Health Organization goal for the year 2000, namely to maintain a natural dentition of not less than 20 teeth throughout life, is substantiated by the current literature review as this proposed dentition will assure an acceptable level of oral function.

Clinical correlates of oral health-related quality of life: evidence from a national sample of British older people.

This study investigated the relationships between an oral health-related quality of life (OHRQoL) indicator and specific clinical dental measures, in a national representative sample of the British older population. A random subsample was drawn from the free-living sample of the National Diet and Nutrition Survey (people aged >or= 65 yr). This subsample consisted of 407 dentate and 346 edentate participants, who were clinically examined and interviewed. The OHRQoL was assessed through the Oral Impacts on Daily Performance (OIDP) indicator. After adjusting for age, gender, and education, dentate subjects with up to 8 occluding pairs of teeth were 2.66 [95% confidence interval (CI): 1.08, 6.51) times, and those with up to 2 anterior occluding pairs were 3.00 (95% CI: 1.55, 5.81) times, more likely to report oral impacts when compared with those having more occluding pairs of teeth. Edentate participants with inadequate denture adaptation were 1.92 (95% CI: 1.04, 3.53) times, and subjects with inadequate denture retention were 2.04 (95% CI: 1.13, 3.69) times, more likely to report oral impacts than the remaining edentate sample in each case. OHRQoL in older British people is significantly related to the number of occluding pairs of natural teeth among the dentate and denture quality among the edentate.

In vitro biofilm formation on the surface of resin-based dentine adhesives.

Prevention of root caries on exposed root surfaces in the aging population is a significant challenge. Bonding resins can be applied to exposed root surfaces as sealants; however, minimal data exists regarding biofilm formation on the surface of these resins. We hypothesized that an antibacterial dentine-bonding resin containing methacryloxydodecyl-pyridiniumbromide (MDPB) may reduce biofilm formation. Biofilms were produced in pooled stimulated natural whole saliva, supplemented with 1% sucrose, on the surface of 5 dentine-bonding resins (Clearfil SE, OptiBond Solo, Protect Bond, Protect Bond Primer, and Xeno III) using untreated root surfaces as controls. Biofilms were stained using the Live:Dead Baclight bacterial viability stain, viewed with confocal microscopy, and analyzed using ImageJ image-analysis software. Resin surfaces encouraged attachment of live bacteria compared with root surfaces. All resins showed similar bacterial colonization in sections adjacent to the resin surface, but in the central and outer portions of biofilms, Xeno III and Protect Bond Primer showed a viable bacterial load similar to that of the root surface. Fluoride-releasing resins (OptiBond Solo/Protect Bond) did not show reduced biofilm formation. Thus, antibacterial agents within the resins have a minimal effect on biofilm formation, particularly when directly adjacent to the root surface.

The impact of falling rates of edentulism.

PURPOSE: The aim of this study was to investigate the impact of both population age changes and falling edentulism rate on the denture market in three European countries. MATERIALS AND METHODS: Detailed information on the rate of edentulism for only three European countries (Finland, Sweden, and the UK) was available. For the UK and Sweden, published predicted rates of edentulism for the future decades were used, whereas predictions for Finland were computed using published edentulism rates. Edentulousness in one jaw was also predicted and included in the computation. Demographic projections were taken from government agency websites. RESULTS: The denture market will decrease in the three countries. Sweden, where edentulism is already low, will experience the largest percentage decrease (60%) over 20 years, but, in absolute number, the change will be of smaller magnitude than that in the UK and Finland. The range of projections for Finland was large, reflecting the difficulty of predicting trends with incomplete information. Within the limitations of this study's design, the impact of population age changes will not increase the denture market in Europe, even with the most pessimistic projections for edentulism rate. CONCLUSION: The complete denture market in Europe will fall despite changing age demographics. The falling rates are large enough to markedly affect future patterns of treatment provision and training.

Penetration of an antibacterial dentine-bonding system into demineralized human root dentine in vitro.

In this study, the penetration of three proprietary dentine-bonding agents (Prime & Bond 2.1, Single Bond, Liner Bond 2) and experimental dentine-bonding systems incorporating an antibacterial monomer, 12-methacryloyloxydodecylpyridinium bromide (MDPB), into artificial root caries lesions was evaluated, and the bactericidal activity of each material against Streptococcus mutans or Lactobacillus casei impregnated into demineralized dentine blocks was assessed. All of the commercial dentine-bonding agents were capable of penetrating into the artificial carious lesions to more than 150 microm. The depth of penetration of the experimental systems, which were based on Liner Bond 2, was not significantly different from that of their parent product. Liner Bond 2 primer exhibited the greatest bactericidal effects among the three proprietary dentine-bonding agents tested. Bactericidal activities of experimental primers containing MDPB were greater than those of any other products, and the application of 4% MDPB-containing primer resulted in complete killing of bacteria in demineralized dentine. The results indicate that the penetration of dentine-bonding agents into extensively demineralized root dentine is possible in vitro, and the experimental dentine-bonding systems containing the antibacterial monomer MDPB are capable of killing bacteria within demineralized dentine. This could be of benefit when managing root caries lesions.