Fracture resistance of human roots filled with mineral trioxide aggregate mixed with phosphate-buffered saline, with and without calcium hydroxide pre-medication.

AIM: To compare the fracture strength of extracted human roots with apical plugs of mineral trioxide aggregate (MTA) mixed with either Ca- and Mg-free phosphate-buffered saline (PBS) or water, with and without calcium hydroxide (CH) canal pre-medication. METHODOLOGY: A total of 180 single-rooted human teeth were prepared to resemble immature roots and divided into groups (n = 20). The negative control received canal irrigation only, and the positive control received intracanal treatment with CH for either two or twelve weeks. MTA mixed with water was used in Group 1: (i) without CH pre-medication - MTA(W); (ii) after 2 weeks CH pre-medication - 2/52CH + MTA(W); and (iii) after 12-week CH pre-medication - 12/52 CH + MTA(W). MTA mixed with PBS was used in Group 2: (i) without CH pre-medication - MTA(PBS); (ii) after 2-week CH pre-medication - 2/52CH + MTA(PBS); and (iii) after 12-week CH pre-medication - 12/52 CH + MTA(PBS). A compressive force was applied to each root until the point of fracture. The results were analysed by the Kruskal-Wallis and Dunn's multiple comparisons tests (P < 0.05). RESULTS: There was no significant difference between groups MTA(W), MTA(PBS) and 2/52CH + MTA(PBS), and all three groups were significantly (P < 0.01, P < 0.05 and P < 0.05, respectively) more resistant to fracture than the negative control. Within Group 1, the samples that received two- (P < 0.01) and twelve-week (P < 0.001) CH pre-treatment were more prone to fracture than those which did not. No difference was found amongst the control groups. The roots of the MTA(PBS) group had a higher dependability (P < 0.05) than the MTA(W) group when compared by the Weibull modulus. The difference was also present when a 2-week CH pre-medication was used. CONCLUSIONS: Mineral trioxide aggregate mixed with Ca- and Mg-free phosphate-buffered saline had a significant strengthening effect on the fracture resistance of structurally weak roots, even when short-term calcium hydroxide pre-medication had been used. MTA mixed with water lost its strengthening effect on human roots when 2- or 12-week CH pre-treatment had been used. Use of CH dressing for up to 12 weeks had no negative effect on fracture resistance of human roots.

Investigating the addition of collagen and its integrin binding sequence (RGD) to glass polyalkenoate: In terms of material and cellular properties to explore a more biocompatible method of root caries restoration.

AIMS: Placement of a restoration to treat root caries disrupts many tissues. There is scope for the restorative material to interact with these to augment reductions in micro leakage afforded by an adhesive restorative material. OBJECTIVES: 1) To investigate the effects of incorporating bioactive molecules into a glass polyalkenoate (GPA) 2) To quantify the changes in physical properties of the material. METHODS: Biocompatibility of the GPA cement (Chemfil Superior, Dentsply De Trey, Konstanz, Germany) in unmodified and modified forms was ascertained using cell culture techniques. The optimum concentration of bioactive components required to promote cell attachment was determined indirectly by quantification and localisation of the fibroblast marker vimentin. The properties of surface hardness, compressive strength and adhesive bond strength were also determined prior to and following addition of the bio-additives: collagen type I and a pentapeptide containing Arg-Gly-Asp (RGD). RESULTS: Addition of Type I Collagen (100µg/ml) and RGD (5mg/ml) to ChemFil Superior had no statistically significant effect upon the compressive strength and bond strength to bovine enamel but significantly (P<0.05) increased the materials shore hardness. The addition of RGD to ChemFil Superior increased most the expression of vimentin, indicating that the cells had become more fibroblastic. This may be indicative of increased synthesis of extracellular matrix macromolecules with the potential to foster adhesion of the modified glass polyalkenoate to distracted gingival tissues. CONCLUSIONS: The results suggest that addition of bioactive molecules to GPA cement for subgingival restorations has potential clinical applications. CLINICAL SIGNIFICANCE: It is possible to envisage that the additions, as described in this paper, could foster the attachment of displaced gingival tissues to GPA restorative materials placed subgingivally where root caries has been treated. This would offer potential to form a seal around the restoration by the attached gingival tissues avoiding a periodontal pocket and depriving residual cariogenic bacteria of a nutrient supply. Further investigation of the effects upon other similar materials of such additions is warranted.

Informing a realistic laboratory erosion-testing regime--observations.

OBJECTIVES: To measure aspects of fizzy drink consumption in a social environment to inform the development of a laboratory testing regime. METHODS: This was an observational study in which participants were invited to attend one of four pizza and soft drink parties. All such foods and drinks were served in an air conditioned room at a temperature of 24°C. All drinks were at a temperature of 4°C and each participant was asked to spit out, into graduated cups, their first and second sips. Both the temperature and volume of these were measured. Upon completion of the party the volume of drinks consumed was determined. Video footage of the experiment was recorded for subsequent analysis to determine sip count and the elapsed time period between first and last sip. These values were compared to the analogous measured value of expectorated volume in order to assess the usefulness of video observation in the context of this work. RESULTS: The mean expectorated beverage temperature was 14.9±2.0°C. The mean time spent drinking was 44.2±17.4 minutes with a mean consumption rate of 13.3±6.0 ml/min. Only the sip volume and sip count per can values were significantly different between sexes (P<0.05) with females displaying lower values for volume and a higher sip count. There was close agreement between the sip volume values observed and calculated using video observation derived parameters. CONCLUSIONS: Several human drinking behaviour values were reported in this study and these will be of value in the development of more realistic laboratory erosion-testing regimes. It is concluded, within the limitations of this work, that (1) there are differences in the drinking behaviour of males and females with respect to sip volume and count, (2) the intraoral rise in temperature of a 4°C beverage is lower than that used in previous laboratory simulations and (3) the values derived from video observation agree with those measured directly validating this technique for use in further studies. CLINICAL SIGNIFICANCE: The work provides valuable quantitative data on which to base simulated laboratory erosion work. Perhaps the most significant finding is that sipped beverages attain a temperature of only 14.9°C.

Effect of saliva and blood contamination on the bi-axial flexural strength and setting time of two calcium-silicate based cements: Portland cement and biodentine.

This study evaluated the effect of contamination with saliva and blood on the bi-axial flexural strength and setting time of pure gray Portland cement and Biodentine (Septodont, Allington, UK). A one-way ANOVA showed that contamination caused no significant difference between the cements in bi-axial flexural strength (P> 0.05). However there was a significant difference in setting time (P

Summary of: a comparative study of bonded and non-bonded amalgam restorations in general dental practice.

OBJECTIVE: This study compared the performance of non-bonded and bonded amalgam restorations in a general dental practice. MATERIALS AND METHODS: A retrospective cohort study was carried out in a general dental practice of amalgam restorations, placed by a single operator. Non-bonded amalgam restorations were analysed over a ten-year period and bonded amalgam restorations over a five-year period. Survival analysis using the Kaplan-Maier method was carried out and an analysis of postoperative sensitivity and reasons for failure. RESULTS: Each group consisted of 231 restorations in 135 patients. Survival rates of non-bonded amalgam restorations were 72.2% over five years and 51.0% over ten years. The survival rate for bonded amalgam restorations was 85.0% over five years. The difference was significant (p <0.0001, 95% CI 1.510-3.226). Analysis of postoperative sensitivity and reasons for failure were inconclusive. CONCLUSION: Within the limitations of the study, bonded amalgam restorations demonstrated greater longevity over non-bonded amalgam restorations and offer significant benefit to patients. Clinicians may feel confident to offer bonded amalgam restorations for their patients as a better alternative than non-bonded amalgam restorations.

An in vitro investigation of the erosive potential of smoothies.

INTRODUCTION: Recent health promotion campaigns have encouraged the public to consume at least five portions of fruit and vegetables per day. Many see consuming fruit smoothies as a way of achieving this. OBJECTIVE: To ascertain the potential or otherwise for fruit smoothies to bring about dental erosion. DESIGN: Laboratory study.Method This was an in vitro investigation in which five varieties of shop bought fruit smoothies, including a 'thickie' were investigated, with respect to their initial pH, titratable acidity and effect upon exposure to the surface microhardness and profile of extracted human teeth. In addition their performance was compared to negative (Volvic(™) water) and positive (orange juice) control drinks as well as a homemade smoothie, based upon the recipe of one of the commercially bought drinks, from which ingredient omissions were made. RESULTS: The majority of the drinks investigated had a baseline pH below the critical pH of enamel (5.5) and required comparable volumes of 0.1M NaOH to raise their pH to neutrality as the positive control. Only two drinks (Volvic(™) still mineral water, the negative control, and the yoghurt, vanilla bean and honey 'thickie') displayed a higher pH, though to neutralise the thickie, a lesser quantity of alkali addition was required. The immersion of the tooth samples in the drinks brought about reductions in their surface hardness (expressed as a percentage change of median hardness) but these were only significant (p <0.001) for the cranberry, blueberry and cherry fruit smoothie and homemade strawberry and banana fruit smoothie. There was no reduction in surface hardness in the case of the teeth immersed in the thickie. Omission of certain ingredients from the homemade smoothie affected the magnitude of surface hardness reductions seen. With regard to the loss of surface contour of the tooth samples following immersion in the drinks, as assessed by depth loss, there were significant differences between the drinks (p = 0.0064) with the thickie and negative control not causing depth loss and the kiwi, apple and lime smoothie producing most depth loss (28.26 (5.45) µm). CONCLUSIONS: Within the limitations of this study some fruit smoothies have the potential to bring about dental erosion if consumed irresponsibly. This can be influenced by ingredient variations. In order to minimise the risk of developing dental erosion, without removing the claimed nutritional benefits of their consumption, their consumption should be confined to mealtimes.

Fibre reinforcement of two temporary composite bridge materials--effect upon flexural properties.

OBJECTIVES: Temporary bridges must survive for their anticipated time in clinical service. Fibre reinforcement offers a potential means of increasing the chances of achieving this. This study sought to investigate this. METHODS: This in vitro study determined the three point flexural strength and flexural fatigue characteristics of beam specimens (25 mm long × 3 mm wide × 2 mm deep) of a chairside temporary crown and bridge material (Protemp 4, 3M ESPE) and a laboratory resin composite (Ceramage, Shofu Inc.) in unreinforced and reinforced states. Reinforcement was provided by Everstick Crown and Bridge (Stick Tech Ltd.) and Ribbond THM (Ribbond Inc.). All testing was performed using an Instron Universal testing machine following one week of storage in distilled water at 37 °C. RESULTS: Fibre reinforcement with Everstick C&B significantly (P < 0.001) increased the mean flexural strengths of both materials. The flexural fatigue limits of both Protemp 4 and Ceramage were significantly (P < 0.001) increased by fibre incorporation. CONCLUSIONS: The observed fibre resin coupling (where Everstick C&B was used) and knitting together of fractured specimen fragments to restore specimen function (specimens where Ribbond THM was used) demonstrated the potential to enhance the durability of temporary bridges made of the materials studied here. CLINICAL SIGNIFICANCE: The incorporation of fibre reinforcement in temporary bridge materials has the potential to enhance the longevity of temporary bridges and thus reduce the need for emergency treatment.

Factors influencing the shade matching performance of dentists and dental technicians when using two different shade guides.

INTRODUCTION: In recent years increased patient aesthetic expectations have brought about closer scrutiny of shade taking and communication processes with the aim of increasing the chances of success of obtaining good indirect restoration appearance. When shade matching, the most popular approach is to match the shade of the natural dentition using a shade guide to specify the shade of the final restoration before fabrication. A recent alternative approach is to also specify the shade of the tooth preparation to facilitate its replication in the die upon which the restoration will be made. OBJECTIVE: To assess (1) the colour vision ability of a sample of dentists and dental technicians and correlate this to their shade matching performance in a simulated clinical situation, and (2) the accuracy and reproducibility of shade matches using two shade guides. DESIGN: In vitro study. METHOD: Consenting dentists and dental technicians within Dundee Dental School and Hospital undertook a Farnsworth-Munsell 100 (FM-100) Hue test and matched (on two separate occasions) the shades of six prepared extracted teeth, containing either a veneer or crown preparation, using both the IPS Natural Die Material shade guide (Ivoclar Vivadent) (IPS) and the Vitapan Classical shade guide (VITA Zahnfabrik) (VC). RESULTS: Eighteen dental technicians (16 males and 2 females) and 40 dentists (21 males and 19 females) completed the study. The raw data revealed that many subjects were inconsistent in their approach to shade matching. The IPS guide afforded greater reproducibility. No significant effects (p >0.05) of subject gender and age upon overall shade matching performance were demonstrated. Performance in the FM-100 Hue test did not statistically affect (p >0.05) the outcome of matching using the guides. CONCLUSIONS: Within the limitations of this study, (a) the FM-100 Hue test was not a good predictor of dental shade matching performance, and (b) both guides performed well in the areas of shade they covered, with the Vita Classical guide matching well shades of natural unstained teeth and the IPS guide matching more closely stained/discoloured preparations.

Disinfection of dental impressions - compliance to accepted standards.

INTRODUCTION: The responsibility of ensuring impressions have been cleaned and disinfected before dispatch to the dental laboratory lies solely with the dentist. Uncertainty of impression disinfection risks both the health of the receiving dental technician and potential repeat disinfection of an already disinfected impression with detrimental consequences for its dimensions. OBJECTIVE: To ascertain, from the perspectives of dentists and dental technicians, current impression decontamination and disinfection practices with, in the case of the technicians, an estimate of the relative prevalence of contaminated voids within apparently disinfected impressions. DESIGN: Anonymous postal questionnaire. METHOD: Dentist (n = 200) and dental technician (n = 200) potential participants, selected at random from the registers held by the General Dental Council, were invited to complete an anonymous postal questionnaire that sought to establish current practices and perceived effectiveness of impression disinfection. RESULTS: Questionnaire return rates of 42.1% and 31.2% were recorded for dentists and dental technicians respectively. A wide range of solutions, at different dilutions of the same product, was used by the dentists to disinfect dental impressions. 37.2% rinsed the impressions with water, and 2.6% always brushed debris away, before disinfection. 24.7% of dentists did not inform the laboratory of disinfection. Irrespective of the disinfection status of the received impressions, 50% of the responding dental technicians disinfected all impressions. 95% of them had received blood-contaminated impressions. 15% had encountered blood-filled voids upon trimming back the peripheries of impressions. 64.7% were confident that the impressions received by them had been disinfected by the dentists. CONCLUSIONS: Compliance with good practice is less than ideal and education in impression disinfection for both dentists and dental technicians is required to address this.

Preoperative occlusal matrix aids the development of occlusal contour of posterior occlusal resin composite restorations--clinical rationale and technique.

This clinical article describes and discusses a technique, using a preoperative occlusal matrix, whereby the occlusal morphology of a tooth may be replicated when placing a posterior resin composite. Two clinical cases are described. The technique offers the clinician considerable time saving for required occlusal adjustment is minimal.

Longevity of conventional and bonded (sealed) amalgam restorations in a private general dental practice.

OBJECTIVE: To compare and contrast the longevity of conventionally placed dental amalgam restorations with those placed using bonding techniques. DESIGN: Retrospective survival analysis (Kaplan Meier) of dental amalgam restorations placed by a single operator in a private general dental practice. SUBJECTS AND METHODS: The records relating to dental amalgam restorations placed between 1 August 1996 and 31 July 2006 were sourced. The details of these were placed into a database that permitted flexible interrogation. Survival data on conventionally placed amalgams (C) and those bonded with either Panavia Ex (PE) or Rely X ARC (RX) were exported into a statistical package to permit survival analysis by the method of Kaplan and Meier.Results The number of restorations available for analysis were C = 3,854, PE = 51 and RX = 1,797. Percentage survival at one year was C = 96.29, PE = 95.65, and RX = 97.58. Percentage survival at five years was C = 86.21, PE = 76.35 and RX = 82.59. A Log Rank test demonstrated no statistically significant difference (p >0.05) in survival between the restoration types. Amalgam restorations bonded with PE or RX exhibited an acceleration of failure rate around 1,000 days post-placement. Further survival analyses of the method of restoration versus type of restored teeth (molar/premolar) and cavity preparation (Class I/II) showed no significant difference in the survival curves in respect of type of restored tooth. In the comparison of Class I and II cavities, the survival curves for the restorations differed significantly (p <0.0001), however when the curves for the Class I restorations alone were compared, no significant difference was found (p = 0.2634). This was also the case for the Class II restorations (p = 0.2260). CONCLUSIONS: Within the limitations of the study, bonding amalgams, compared to placing them conventionally, afforded no significant benefit upon restoration longevity. This, coupled with the emerging trend of an accelerating decline in longevity of bonded amalgams from 1,000 days onwards and with the greater cost, challenges the justification for routine bonding of amalgams.

A laboratory investigation of consumer addition of UHT milk to lessen the erosive potential of fizzy drinks.

INTRODUCTION: Much recent attention has been given to the erosive potential of carbonated beverages. Some have shown that the risks of developing erosion, if such drinks are consumed once daily and four times daily, are respectively 2.2 and 5.13 times greater than if they are not consumed at all. The addition of ultra-heat treated (UHT) milk to such beverages has been identified by a survey as common practice in Pakistan. It is known that the addition of calcium to orange juice and acidic candies reduces the capacity of these dietary items to produce dental erosion by the law of mass action. While potentially helpful, such a practice at manufacture may affect adversely product stability and flavour, thus compromising market share. As a result an alternative approach is for the consumer to carry out such modification. The addition of milk is one such potential means.Objective To assess the capacity of six brands of carbonated drinks to bring about dental erosion and determine if consumer modification by the addition of milk affected this. DESIGN: In vitro study. METHOD: For each drink in both manufactured and consumer modified (25 ml of drink with 6.25 ml UHT milk) states, the pH and titratable acidity were measured. These assessments were also made for distilled water dilution of the manufactured drinks in the ratio of 1 part drink to 0.25 parts water. In addition, the effects of a 60 min exposure to the drinks in manufactured and consumer modified states, upon the surface microhardness and profile of human molar buccal tooth substance were determined. RESULTS: The addition of milk significantly increased the mean pH (p <0.001) and decreased the mean titratable acidity (p <0.001). Its addition had significantly more (p <0.001) than a simple dilution effect upon these values. Milk addition significantly lessened (p <0.001) the reductions in surface microhardness of tooth substance when exposed to the drinks except in the case of one beverage. There was, however, no significant effect (p = 0.0732) of its inclusion upon the depth loss of tooth substance. CONCLUSIONS: Within the limitations of this study, the addition of milk to carbonated beverages reduced overall their capacity to bring about dental erosion.

Rheological properties of veneer trial pastes relevant to clinical success.

INTRODUCTION: The porcelain veneer is a relatively conservative means of improving the appearance of teeth. As these restorations are usually highly visible it is essential to gain the approval of the patient before final cementation takes place. As a result a variety of trial pastes are available that match the shades of the resins that are used ultimately to finally cement the veneer in place. Such restorations, by virtue of their small size and fragility, are difficult to handle and position. It is therefore important that the application of trial paste does not impede placement and retention upon the tooth surface at try in whilst the patient assesses its appearance. OBJECTIVE: To determine the rheological properties of three makes of trial pastes (Calibra - Dentsply Caulk, USA; Nexus - Kerr, USA; Rely X - 3M Espe, USA) and assess if temperature affected these. Design In vitro rheological measurement. METHOD: For each product the rheological properties of three shades were determined at both 25 degrees C and 35 degrees C three times. Measurements of both the Initial Yield Stress and Shear Rate Index were undertaken using a controlled stress rheometer (Carri-med, Dorking, UK) in flow mode with a cone-and-plate test configuration. RESULTS: One way analyses of variance of the initial yield and shear rate index for each shade of material at 25 and 35 degrees C demonstrated no significant effects of temperature with the exception of the initial yield of Nexus (P = 0.0024) where the yield stress of the white shade was significantly (P <0.01) higher at 35 degrees C than at 25 degrees C. In all cases the yield stress for Nexus was of the order of ten times higher than the other materials. All materials demonstrated pseudoplastic behaviour. CONCLUSIONS: The variation in yield stress displayed by the materials will affect the handling of veneers and offers a potentially useful choice parameter to the clinician as to which paste bests suits their requirements.

Evaluation of a head mounted camera for clinical dental teaching.

OBJECTIVE: To evaluate the potential of a novel head mounted camera to both improve the level of detail observed by learners/teachers observing dental procedures being undertaken and to improve the level of feedback given to learners. DESIGN: Questionnaire. SUBJECTS AND METHODS: Qualified members of the dental team and those in training evaluated the usefulness of the application of a novel head mounted camera in their clinical teaching within Dundee Dental School and Hospital. RESULTS: A total of 210 questionnaires were issued and received for analysis. Although the device generally improved the level of detail observed by learners/teachers and improved the level of feedback given to learners, there was scope for improving upon image quality. The lighting of the environment in which the camera was used was a critical factor in optimising success. The different members of the dental team displayed different expectations of the device. This was attributed in part to their level of previous exposure to clinical work. In applying this technology it is therefore important to understand the needs of the user. CONCLUSIONS: The camera system did enhance the learning experience but required further refinement in relation to image quality.

Eye care habits of dentists registered in the United Kingdom.

OBJECTIVE: To determine the current eyecare behaviour of dentists and compare this against published standards concerning frequency of sight test intervals and eye protection. SUBJECTS AND METHODS: Four hundred dentists were selected at random for inclusion in the study from the UK 2004 Dentists Register. They were invited to complete a questionnaire that ascertained their gender and age, current eyesight status and method of correction, elapsed time interval since their last eyesight test and reason for attendance. In addition, the use and power of magnification was sought along with the adoption of protective eyewear. Responses were coded and placed in a relational database to facilitate interrogation and subsequent statistical analysis. RESULTS: The questionnaire return rate was 63% (247 and allowing for the seven questionnaires returned marked unknown at this address). Of these 158 were males and 81 female. The majority worked in general dental practice. Those with known eyesight deficiencies were statistically more likely (p < 0.01) to attend for routine eye examination. Sixteen percent of respondents failed to attend for routine eye examination at least every two years. The mean age of those who had detected a change in their eyesight and sought examination was 43.59 (SD = 10.57) for males and 39.07 years (SD = 9.41) for females. This mirrored closely the mean age when the use of magnification was adopted (males = 42.39 (10.30), females = 40.33 (10.55)). The use of magnification was not universally adopted. Eye protection compliance was a low as 57% when using laboratory cutting equipment. CONCLUSIONS: Although compliance with accepted recommendations for biannual eyesight testing was higher than that for the general population, not all dentists complied. The adoption of protective eyewear was patchy and exposed dentists to unnecessary risk.

Maxillary incisor palatal erosion: no correlation with dietary variables?

The objectives of the study were to examine a relationship between tooth erosion affecting the palatal aspects of permanent maxillary central incisors with dietary, behavioral and medical variables. The methods included, 251 schoolchildren aged 11 to 13 years were recruited to participate. Each subject had dental impressions of the palatal aspects of both upper central incisors recorded at baseline, 9 and 18 months intervals. From these, electroconductive replicas were fabricated, mapped and compared using a surface matching technique. At the end of the study all participants underwent a structured interview that sought to assay the level of potential erosive dietary, behavioral and medical risk factors. Correlation analyses of the responses given in the final structured interview with the degrees of palatal tooth substance loss (both previous and measured) were under taken. The results showed: (1) The degree of previous erosion did not predict the level of measured ongoing erosion. (2) Brushing the teeth more frequently with fluoridated toothpaste correlated significantly with lower levels of ongoing erosion (P = 0 011). It was concluded that: (1) Evidence of previous palatal erosion did not predict future erosion. (2) The application of topical fluoride as a by-product of tooth brushing may provide an element of protection against palatal erosion. (3) In view of the lack of correlation between exposure to potential risk factors and the level of ongoing palatal tooth surface loss in this study, other factors (such as an individual's susceptibility and salivary buffering power) may well be more important predictors. The clinical relevance included: Preventive advice to patients with dental erosion should not only include the use of topical fluoride, in the form of toothpaste, but recognize individual susceptibility to this condition.

Rationalization of quantitative tooth surface loss data for epidemiological research.

Recent UK National Surveys have revealed a high prevalence of tooth surface loss (TSL) because of erosion in Children and Adolescents. Although digital surface mapping and surface matching techniques may be used to quantify its progression with time, reporting TSL of individuals as a function of either mean depth loss or volume loss, this can be inadequate when transferred for epidemiological analysis. For example, a tooth displaying multiple regions of depth loss may deserve to be distinguished from a tooth with a single localised area of erosion, although the total volume change may be the same. A potential solution, explored here, is to use both the quantitative wear data and colour coded surface representation plots generated by such methods to arrive at a single categorical wear score [1 (< or = 5% of surface exhibits TSL) to 5 (> or = 51% of surface exhibits TSL)]. Two examiners independently categorized, on two separate occasions, the TSL of 53 maxillary incisors (26 subjects observed at baseline and 9 months). Their performance was assessed for intra- and inter-examiner agreement by; (i) calculating the percentage of agreement, (ii) a Wilcoxon matched-pairs signed rank test. Thereafter, in cases of disagreement a consensus score was allocated and a regression analysis of this versus the numerically derived percentage of the surface that had undergone change was carried out. Intra- and inter-examiner agreement was 100 and 88.7% respectively and for the inter-examiner comparison P = 0.0456. The categorical scores and the quantitative wear data correlated linearly (R = 0.82). It is concluded that the method used to rationalize the quantitative TSL data is both reproducible and reflects the quantitative data. Its use should be helpful in epidemiological TSL studies but continued vigilance is required in cases of examiner disagreement.