Predictive clinical utility of pre-hospital point of care lactate for transfusion of blood product in patients with suspected traumatic haemorrhage: derivation of a decision-support tool.

INTRODUCTION: Pre-hospital emergency medical teams can transfuse blood products to patients with suspected major traumatic haemorrhage. Common transfusion triggers based on physiological parameters have several disadvantages and are largely unvalidated in guiding pre-hospital transfusion. The addition of pre-hospital lactate (P-LACT) may overcome these challenges. To date, the clinical utility of P-LACT to guide pre-hospital blood transfusion is unclear. METHODS: A retrospective analysis of patients with suspected major traumatic haemorrhage attended by Air Ambulance Charity Kent Surrey Sussex (KSS) between 8 July 2017 and 31 December 2019. The primary endpoint was the accuracy of P-LACT to predict the requirement for any in-hospital (continued) transfusion of blood product. RESULTS: During the study period, 306 patients with suspected major traumatic haemorrhage were attended by KSS. P-LACT was obtained in 194 patients. In the cohort 103 (34%) patients were declared Code Red. A pre-hospital transfusion was commenced in 124 patients (41%) and in-hospital transfusion was continued in 100 (81%) of these patients, in 24 (19%) patients it was ceased. Predictive probabilities of various lactate cut-off points for requirement of in-hospital transfusion are documented. The highest overall proportion correctly classified patients were found for a P-LACT cut-point of 5.4 mmol/L (76.50% correctly classified). Based on the calculated predictive probabilities, optimal cut-off points were derived for both the exclusion- and inclusion of the need for in-hospital transfusion. A P-LACT < 2.5 mmol/L had a sensitivity of 80.28% and a negative likelihood ratio [LR-] of 0.37 for the prediction of in-hospital transfusion requirement, whereas a P-LACT of 6.0 mmol/L had a specificity of 99.22%, [LR-] = 0.78. CONCLUSION: Pre-hospital lactate measurements can be used to predict the need for (continued) in-hospital blood products in addition to current physiological parameters. A simple decision support tool derived in this study can help the clinician interpret pre-hospital lactate results and guide pre-hospital interventions in the major trauma patient.

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.

Idiopathic Neonatal Subpial Hemorrhage with Underlying Cerebral Infarct: Imaging Features and Clinical Outcome.

BACKGROUND AND PURPOSE: Neonatal subpial hemorrhage with underlying cerebral infarct is a previously described but poorly understood clinicoradiographic syndrome. We sought to further characterize the cranial ultrasound and MR imaging characteristics and associated outcomes of this condition across the full range of gestational ages, including extreme and very preterm neonates. MATERIALS AND METHODS: This was a single tertiary pediatric center retrospective case series. Brain MR imaging and cranial ultrasound of neonates with subpial hemorrhage with underlying cerebral infarct were identified from a population-based radiology registry (2006-2020). Original images were reviewed by 2 neuroradiologists blinded to history and outcome. Clinical presentation, course, and outcome at >12 months were abstracted from medical records. The diagnostic utility of cranial ultrasound was compared with that of MR imaging. RESULTS: Sixteen patients were included (median gestational age, 36.5 weeks; range, 27-41 weeks; 31% premature). MR images were obtained acutely at the time of presentation between days 0 and 9 of life. On T2WI and DWI, a consistent presence of a hypointense subpial bleed and an underlying hyperintense cerebral cortex were recognized, which created a distinct MR imaging pattern resembling the yin-yang symbol. Findings of all the MRAs and MRVs were normal. Cranial ultrasound detected 6 of 7 MR imaging lesions with sonographic features correlating well with MR imaging. The 3 extreme or very preterm neonates did not survive. The remainder survived with relatively mild neurologic deficits. CONCLUSIONS: Subpial hemorrhage with underlying infarction is a recognizable condition with unique MR imaging and sonographic features. Improved recognition may advance understanding of risk factors and outcomes.

Long-term stability of limiting nasal alar base width changes with a cinch suture following Le Fort I osteotomy with submental intubation.

The aim of this study was to assess the effectiveness of the nasal alar base cinch suture following Le Fort I osteotomy at long-term follow-up. One hundred and forty participants (89 female, 51 male) aged between 16 and 51 years underwent Le Fort I osteotomy with submental intubation. Anthropometric measurements of the nose were taken intraoperatively, immediately postoperative, and for up to 3 years postoperative: the maximum lateral convexity of the alae (Al-Al) and the lateral extremity of the alar base curvature at the alar groove (Ac-Ac). The use of a cinch suture was recorded. The results were analysed using a linear mixed-effects model analysis. One hundred and six participants had cinch sutures and 34 had no cinch sutures. Following Le Fort I osteotomy, there were significant increases in Ac-Ac (by 4.29mm) and Al-Al (by 3.70mm) (both P<0.0001). Cinch sutures significantly reduced the widths back to preoperative values (P<0.0001). Alar width remained stable over 3 years, with an increase of 0.36mm for Al-Al (P>0.05) and 1.03mm for Ac-Ac (P<0.05) compared to the postoperative measurement. In conclusion, a cinch suture was helpful in reducing the unwanted alar base width changes, which were found to be relatively stable at 3 years.

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.

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.

The utility of molecular diagnostics to predict recurrence of head and neck carcinoma.

BACKGROUND: Locoregional recurrence is the major cause of treatment failure after surgery for oral squamous cell carcinoma. Molecular diagnostics have the potential to improve on clinicopathological parameters to predict this recurrence and plan adjuvant treatment. The test most frequently applied is based on detecting TP53 mutations, but alternative methodology is required for cases that harbour the wild-type gene. METHODS: One hundred and two cases with tumour-adjacent margins, considered to be clear margins by microscopy, were examined using carefully optimised molecular diagnostics based on detection of the TP53 and Ly-6D markers. The markers were also combined to provide a dual approach. RESULTS: The dual molecular diagnostic identified cases with a significant increase in the probablility of developing locoregional recurrence when tumour-adjacent positive and clear margins were compared (P=0.0001). These tests were most useful when the clearance at the resection margins was 5 mm or less. The TP53-based diagnostic was a better predictor of locoregional recurrence than established clinicopathological parameters. CONCLUSION: The optimised TP53-based diagnostic rapidly identifies an important subgroup of cases with close margins that will benefit from new treatment modalities to reduce the risk of recurrence.

Microbiochemical analysis of carious dentine using Raman and fluorescence spectroscopy.

The aim of this study was to evaluate and correlate objectively the microspectroscopically derived biochemical components of sound, infected and affected carious dentine with their microhardness and autofluorescence (AF) characteristics. Over 3 million high-resolution Raman spectra from 8 extracted human carious teeth were recorded using Raman spectrometer with parallel spectrum acquisition. Green AF signals across each carious lesion from all samples were acquired with a similar spatial resolution using confocal fluorescence microscopy. The Knoop microhardness (KHN) from a total of 233 co-localized areas was recorded from the same samples and allocated subjectively into the three zones. Cluster analysis of the Raman data, performed using in-house software, produced five independent spectral components representing mineral content, protein content, porphyrin fluorescence (PF), putative infected dentine signal (IDS) and affected dentine signal (ADS). The distributions of the 5 Raman components and the AF signal were matched across all samples and their average values were calculated for each corresponding KHN area. The infected dentine was defined significantly by the KHN, AF and by the relative contribution of the mineral, PF and IDS clusters. Protein cluster was not statistically related to the KHN or AF. A delineation between affected and sound dentine was observed using the KHN, AF, PF and ADS parameters. This study concludes that micro-Raman spectroscopy can provide a non-invasive and objective evaluation of different carious dentine zones. Being able to detect and assess clinically the caries-affected dentine during minimally invasive operative caries management is important to control the risk of unnecessary tissue removal.

Changes in centring and shaping ability using three nickel­titanium instrumentation techniques analysed by micro-computed tomography (µCT).

AIM: To compare the centring ability and the shaping ability of ProTaper (PT) files used in reciprocating motion and PT and Twisted Files (TF) used in continuous rotary motion, and to compare the volume changes obtained with the different instrumentation techniques using micro-computed tomography. Methodology Sixty mesial canals of thirty mandibular molars were randomly assigned to three instrumentation techniques: group 1, canals prepared with the PT series (up to F2) (n = 20); group 2, canals prepared with the F2 PT in reciprocating motion (n = 20); group 3 canals prepared with the TF series (size 25) (n = 20). Teeth were scanned pre- and postoperatively using micro-computed tomography to measure volume and shaping changes, and the obtained results were statistically analysed using parametric tests. Results The increase in canal volume obtained with the three instrumentation techniques was not significantly different. Canals were transported mostly towards the mesial aspect in the apical- and mid-third of the roots, and towards the furcal aspect coronally. No difference in the transportation and centring ratio was found between the techniques. There was no significant difference between the times of instrumentation (TF: 62.5 ± 5.4 s; PT: 60.6 ± 3.9 s; and F2 PT file in reciprocating motion: 51.0 ± 3.3 s). Conclusions ProTaper files used in reciprocating motion and PT and TF used in continuous rotary motion were capable of producing centred preparations with no substantial procedural errors.

Effects of MMP inhibitors incorporated within dental adhesives.

Matrix metalloproteinase (MMP) inhibition has been shown to reduce adhesive bond degradation when applied as a pre-conditioner, adding to clinical steps in the placement of adhesives, but their incorporation within dental adhesives has not been fully explored. This study examined the effect of including 2 MMP inhibitors (BB94 and GM6001) within the primers of 3 commercially available adhesives. Fluorometric assay and zymography showed that adhesives with MMP inhibitors had high affinity toward both synthetic fluorogenic FRET peptides (95%) and dentin powder substrates, respectively. The immediate microtensile bond strength was enhanced for 2 types of adhesives following the addition of both inhibitors. However, no changes were detected between the control and the inhibitor groups following 3-month storage. The modified two-step etch-and-rinse and single-step systems showed less Rhodamine B penetration to the "hybrid layer" and to the "adhesive", respectively. The incorporation of BB94 and GM6001 within the primers resulted in the inhibition of dentin MMPs with improved initial bond strength and enhanced sealing ability.

Does the Eastman correction over- or under-adjust ANB for positional changes of N?

Cephalometric analyses are useful for planning and provision of orthodontic treatment. A and B points are used to resemble the anterior part of maxilla and mandible and N represents the anterior part of the cranial base. The position of N may influence measurements of SNA, SNB, and ANB and changes of N in the antero-posterior plane are thought to have a larger influence on the above measurements than vertical ones. Several methods have been proposed to address this issue, such as the Wits appraisal, the 'Individualized ANB', and the 'Eastman correction'; the latter is mainly used in the UK. This study used a geometrical model of a lateral cephalogram with standard Caucasian average values for SN length, position of A and B points for male and female patients. Linear and angular measurements were digitized using Dolphin™ Imaging software. N was moved in antero-posterior and vertical planes and subsequent changes of SNA, SNB, and ANB were measured and the Eastman correction applied. The correction overestimated the SNA and ANB values in the opposite direction to the directly measured SNA and ANB when N moved posteriorly towards S: The directly measured values tended to show a Class II relationship but the correction indicated a Class III skeletal base. As N moved anteriorly, the Eastman correction overestimated the measured Class III skeletal relationship; SNA did not fall below 81 for correction in the opposite direction. Vertical positional changes had little impact on the underlying ANB and correction was not indicated clinically.

The association of tooth wear, diet and dietary habits in adults aged 18-30 years old.

OBJECTIVE: The association of acidic foods and drinks to the development of erosive tooth wear was investigated in a single cohort of adults aged 18-30 years. METHOD: A tooth wear index was recorded on 1010 participant's who had a mean age of 21.9 years (SD 0.1) and of which 70% were female and 30% males. Participant's completed a previously validated questionnaire containing 50 questions about current and historical dietary habits. Data were analysed at the tooth level using odds ratio. RESULTS: Tooth wear was statistically significantly associated to acidic foods and drinks with high titratable acidity and dietary habits, including drinking from a glass and holding drinks, (OR 5 and 6.5 respectively). A history of heartburn was statistically significantly associated to palatal dentine exposure (p≤0.05 and OR 7.6). CONCLUSION: In this sample of adults, tooth wear was associated to a number of acidic dietary products and drinking habits.

A new index to measure tooth wear--methodolgy and practical advice.

A new tooth wear index, designed to measure stages of tooth wear in enamel and dentine is presented. The index measures the lateral spread of wear in enamel and the depth of tooth wear in dentine. The index scores enamel loss at 5 levels and 6 levels in dentine and provides a more sensitive index for monitoring the progression of wear than older indices. The protocols and methods of the index are described and incorporate refinements based on the combined experiences of two independent studies conducted on adults and children. The findings of both studies are summarised and recommendations are made for future studies which investigate the prevalence of tooth wear in adults or children.

Effectiveness and acceptability of face-to-face, blended and e-learning: a randomised trial of orthodontic undergraduates.

AIM: This study compared e-learning (EL), face-to-face learning (F2FL) and blended learning (BL) with respect to their effectiveness and student attitudes towards them. It also evaluated the effect of the order in which the components (EL and F2FL) of blended learning are delivered. DESIGN: This was a prospective cluster randomised trial comparing four parallel groups. METHOD: Eight groups of fourth year dental undergraduate students were randomly allocated to one of four intervention groups: EL, F2FL, BL1 or BL2. These four groups were assessed for their baseline comparability of knowledge and skills. Each then received the same cephalometric tutorial but delivered by the allocated mode of learning. Effectiveness was immediately assessed with a MCQ which measured short-term recall of knowledge. Student attitudes were evaluated with a questionnaire followed by a focus group discussion. RESULTS: Ninety (57%) students completed the study. Pearson's chi-square test found no statistically significant difference between F2FL and BL; EL alone was less effective (P<0.05) for four MCQ questions but with no difference for the remaining six questions. Overall students were positive towards each learning modality, but a one-way analysis of variance found BL was the most and F2FL was the least accepted (P=0.002). EL was significantly (P=0.028) less preferred. The order of the components in BL had no significant effects. CONCLUSION: These results suggest that BL is more likely than either F2FL or EL alone, to be both effective and accepted when delivering cephalometric education to undergraduates.

Grading oral epithelial dysplasia: analysis of individual features.

BACKGROUND: Assessing epithelial dysplasia to predict malignant transformation remains problematic in many tissues because grading systems are poorly structured and individual features poorly defined. Dysplasia grading is criticised for lack of reproducibility and poor predictive value. Grading systems for upper aerodigestive tract dysplasia have evolved over several decades and are not supported by good outcome experimental data. METHODS: This study analysed the individual features of dysplasia in 86 oral dysplastic lesions and determined the reproducibility of scoring for each, and correlated them with other features and clinical factors using complex clustering analyses. RESULTS: A uniform pattern of dysplasia was found in 37 lesions, focal dysplasia in 36 and in 13 lesions dysplasia formed complex discontinuous patterns. There was wide variation in reproducibility of scoring of individual features and many, including thickness, some types of rete morphology, basaloid cell anisonucleosis, basal dyscohesion, and dyskeratosis as deep single cells correlated with sub-sites. Rete morphology, type of keratinisation, hyperchromatism of the basaloid compartment, prickle cell anisonucleosis and extension down salivary ducts correlated with smoking. Conventional grading and oral intraepithelial neoplasia (OIN) grading by 'thirds affected' showed strong correlation overall but scores obtained with the OIN system tended to a higher grade at all sites except soft palate/fauces. There was poor correlation between the systems for moderate dysplasia and also severe dysplasia at some sites. Individual features could not be shown to cluster to form distinct patterns of dysplasia. CONCLUSIONS: These variations may account in part for the lack of reproducibility and poor predictive value of the grading systems in current use and could inform the design of future grading systems.

An in vitro investigation of peak insertion torque values of six commercially available mini-implants.

This study compared peak insertion torque values of six commercially available self-drilling mini-implants [Mini Spider® screw (1.5 × 8 mm), Infinitas® (1.5 × 9 mm), Vector TAS® (1.4 × 8 mm), Dual Top® (1.6 × 8 mm), Tomas Pin® (1.6 × 8 mm), and Ortho-Easy® (1.7 × 6, 8, and 10 mm)]. Twenty implants each were drilled into acrylic rods at a speed of 8 rpm using a motorized torque measurement stand, and the values were recorded in Newton centimetres (Ncm). A further 20 Ortho-Easy® implants with a length of 6 and 10 mm were tested at 8 rpm; 20 implants of 6 mm length were also tested at 4 rpm. Kaplan-Meier estimates of the peak torque values were compared using the log-rank test with multiple comparisons evaluated by Sidak's test. There were significant differences in the maximum torque values for different mini-implants with the same length. The Mini Spider® screw and Infinitas® showed the lowest average torque values (6.5 and 12.4 Ncm) compared with Vector TAS®, Dual ToP®, Tomas Pin®, and Ortho-Easy® (30.9, 29.4, 25.4, and 24.8 Ncm, respectively). There was no correlation between the diameter of the implants and torque values. The Tomas Pin® showed the largest standard deviation (7.7 Ncm) and the Dual Top® implant the smallest (0.6 Ncm). Different insertion speeds did not result in significant differences in peak torque values but the 6 mm mini-implants showed significantly higher torque values than the 8 and 10 mm implants. Using a 'torque limiting' screwdriver or pre-drilling cortical bone to reduce insertion, torque appears justified for some of the tested implants.

Debonding force and deformation of two multi-stranded lingual retainer wires bonded to incisor enamel: an in vitro study.

The aim of the study was to examine, in vitro, the effect of a vertical force on the debond force and deformation of two multi-stranded wires bonded to the lingual enamel of lower incisor teeth. Two different stainless steel wires were used, 0.016 × 0.022 inch (Bond-A-Braid® Reliance Orthodontic Products) and a three-stranded 0.0175 inch wire (Ortho Technology). An in vitro model was used to simulate a vertical force at the interdental wire. Twenty-six pairs of incisors were placed in two groups. A 15 mm length of wire was bonded to the lingual surfaces of each pair of incisors using a common bonding technique. A vertical force was applied to the midpoint of the interdental wire, using an Instron universal testing machine. The failure characteristics examined included the maximum force for debond, the degree of wire deformation, and the site of failure. Significance was predetermined at P < 0.05 and multiple comparisons indicated no significant differences (P = 0.147) in the initial mean bond strength between the 0.0175 inch (41.44 N) and 0.016 × 0.022 inch (37.70 N) wires. The main failure type for both the initial and second debond events was fracture of composite bond at the wire-composite interface, cohesive failure. Both wires exhibited similar mean degrees of deflection of 1.30 and 1.51 mm for the 0.0175 inch and 0.016 × 0.022 inch wires, respectively. Rebonding to enamel resulted in significantly lower (P = 0.001) mean bond strength for both wires, 0.0175 inch (13.86 N) and 0.016 × 0.022 inch (14.17 N) in comparison with the initial bond strength. Rebonding to previously bonded enamel may be unpredictable and may lead to higher failure rates of bonded lingual retainers.

Palatally impacted canines and the modified index of orthodontic treatment need.

The aim of this study was to assess the severity of any underlying malocclusion in subjects presenting for treatment of a palatally impacted canine (PIC) using a modification of the Dental Health Component (DHC) of the Index of Treatment Need (MIOTN), which does not factor in the impacted canine. The pre-treatment study models of 54 subjects who had previously undergone surgical exposure of a PIC, followed by fixed appliance orthodontic alignment, were scored independently by two examiners on two occasions using the MIOTN system. Unweighted kappa statistics revealed good intraoperator agreement for the two examiners and a moderate level of interexaminer agreement. Forty-six and 41 per cent of the sample still scored either an MIOTN grade 4 or 5 (i.e. a great or very great need of orthodontic treatment). However, 20 and 25 per cent of the subjects were graded with a MIOTN score of 1 or 2, indicating little or no need for treatment when the PIC was not taken into consideration. This finding emphasizes the importance of early diagnosis of an impacted canine and the need to institute interceptive measures where necessary, as up to 25 per cent of patients might otherwise require no other orthodontic treatment.

A new index of tooth wear. Reproducibility and application to a sample of 18- to 30-year-old university students.

A modified wear index, in which the wear of enamel and dentine are recorded separately, is described. The index was applied to estimating the prevalence and extent of tooth wear in a single convenience sample of 18- to 30-year-old students attending a university in London. The subjects were examined under good lighting in a dental chair away from a dental school. A total of 707 females and 303 males were recruited with a mean age of 21.9 years (standard deviation = 0.1, range = 18-30) and examined by 3 trained and calibrated examiners. Intra-examiner intra-class correlation coefficients showed a range of 0.44-0.88. The unweighted kappa scores were above 0.88 for enamel and dentine. The presence of enamel wear was common to all subjects, but 6.1% of the participants had more than one third of the tooth surface affected. Dentine was exposed on 5.3% of all surfaces, with the largest proportion accounting for less than 10% of the tooth surface (grade 1). The proportion of subjects with at least 1 surface with dentine exposed was 76.9% of the total population. The males had significantly more wear in dentine than the females (p = 0.001). The inter-examiner intra-class correlation coefficients for enamel and dentine were 0.87 and 0.92, respectively. The reproducibility of the index was comparable to other analyses and provides an opportunity to assess the prevalence of enamel wear in large population-based studies.

The effects of social class and dental attendance on oral health.

The relationship between socio-economic status (SES) and oral health is well-established. We investigated whether the association between SES and the number of sound teeth in adults is explained by dental attendance patterns, in turn determined by the effect of SES on barriers to dental attendance. Data on 3817 participants from the 1998 Adult Dental Health Survey in the UK were analyzed. Using structural equation modeling, we found a model with 4 factors (aging, SES, attendance-profile, and barriers-to-dental-attendance) providing an adequate fit to the covariance matrix of the 9 covariates. The final model suggests that the association between SES and the number of sound teeth in adults in the UK is partially explained by the pathway [SES --> barriers-to-dental-attendance --> dental-attendance-profile --> number-of-sound-teeth]. A direct relationship, SES --> number-of-sound-teeth, is also significant.