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Background The management of dental caries has traditionally involved removal of all soft demineralised dentine before a filling is placed. However, the benefits of complete caries removal have been questioned because of concerns about the possible adverse effects of removing all soft dentine from the tooth. Three groups of studies have also challenged the doctrine of complete caries removal by sealing caries into teeth using three different techniques. The first technique removes caries in stages over two visits some months apart, allowing the dental pulp time to lay down reparative dentine (the stepwise excavation technique). The second removes part of the dentinal caries and seals the residual caries into the tooth permanently (partial caries removal) and the third technique removes no dentinal caries prior to sealing or restoring (no dentinal caries removal). This is an update of a Cochrane review first published in 2006. Objectives To assess the effects of stepwise, partial or no dentinal caries removal compared with complete caries removal for the management of dentinal caries in previously unrestored primary and permanent teeth. Search methods The following electronic databases were searched: the Cochrane Oral Health Group's Trials Register (to 12 December 2012), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 11), MEDLINE via OVID (1946 to 12 December 2012) and EMBASE via OVID (1980 to 12 December 2012). There were no restrictions regarding language or date of publication. Selection criteria Parallel group and split-mouth randomised and quasi-randomised controlled trials comparing stepwise, partial or no dentinal caries removal with complete caries removal, in unrestored primary and permanent teeth were included. Data collection and analysis Three review authors extracted data independently and in triplicate and assessed risk of bias. Trial authors were contacted where possible for information. We used standard methodological procedures exacted by The Cochrane Collaboration. Main results In this updated review, four new trials were included bringing the total to eight trials with 934 participants and 1372 teeth. There were three comparisons: stepwise caries removal compared to complete one stage caries removal (four trials); partial caries removal compared to complete caries removal (three trials) and no dentinal caries removal compared to complete caries removal (two trials). (One three-arm trial compared complete caries removal to both stepwise and partial caries removal.) Four studies investigated primary teeth, three permanent teeth and one included both. All of the trials were assessed at high risk of bias, although the new trials showed evidence of attempts to minimise bias. Stepwise caries removal resulted in a 56% reduction in incidence of pulp exposure (risk ratio (RR) 0.44, 95% confidence interval (CI) 0.33 to 0.60, P < 0.00001, I2 = 0%) compared to complete caries removal based on moderate quality evidence, with no heterogeneity. In these four studies, the mean incidence of pulp exposure was 34.7% in the complete caries removal group and 15.4% in the stepwise groups. There was also moderate quality evidence of no difference in the outcome of signs and symptoms of pulp disease (RR 0.78, 95% CI 0.39 to 1.58, P = 0.50, I2 = 0%). Partial caries removal reduced incidence of pulp exposure by 77% compared to complete caries removal (RR 0.23, 95% CI 0.08 to 0.69, P = 0.009, I2 = 0%), also based on moderate quality evidence with no evidence of heterogeneity. In these two studies the mean incidence of pulp exposure was 21.9% in the complete caries removal groups and 5% in the partial caries removal groups. There was insufficient evidence to determine whether or not there was a difference in signs and symptoms of pulp disease (RR 0.27, 95% CI 0.05 to 1.60, P = 0.15, I2 = 0%, low quality evidence), or restoration failure (one study showing no difference and another study showing no failures in either group, very low quality evidence). No dentinal caries removal was compared to complete caries removal in two very different studies. There was some moderate evidence of no difference between these techniques for the outcome of signs and symptoms of pulp disease and reduced risk of restoration failure favouring no dentinal caries removal, from one study, and no instances of pulp disease or restoration failure in either group from a second quasi-randomised study. Meta-analysis of these two studies was not performed due to substantial clinical differences between the studies. Authors' conclusions Stepwise and partial excavation reduced the incidence of pulp exposure in symptomless, vital, carious primary as well as permanent teeth. Therefore these techniques show clinical advantage over complete caries removal in the management of dentinal caries. There was no evidence of a difference in signs or symptoms of pulpal disease between stepwise excavation, and complete caries removal, and insufficient evidence to determine whether or not there was a difference in signs and symptoms of pulp disease between partial caries removal and complete caries removal. When partial caries removal was carried out there was also insufficient evidence to determine whether or not there is a difference in risk of restoration failure. The no dentinal caries removal studies investigating permanent teeth had a similar result with no difference in restoration failure. The other no dentinal caries removal study, which investigated primary teeth, showed a statistically significant difference in restoration failure favouring the intervention. Due to the short term follow-up in most of the included studies and the high risk of bias, further high quality, long term clinical trials are still required to assess the most effective intervention. However, it should be noted that in studies of this nature, complete elimination of risk of bias may not necessarily be possible. Future research should also investigate patient centred outcomes.

The caries lesion is a sign or symptom resulting from numerous pH fluctuations in biofilms on teeth. The lesion may or may not progress and lesion progression can be controlled, slowed down or arrested. Control of the biofilm is the treatment of caries, the most important measure being to disturb the biofilm mechanically using a fluoride-containing toothpaste. The informed patient controls caries and the role of the dental professional is to advise how this should be done. This is the non-operative treatment of caries and it is worthy of payment. It should be mandatory as part of any operative treatment to ensure that the patient understands, and is able to perform, adequate plaque control. Clinical Relevance: It is very unfortunate that the current remuneration scheme (Unit of Dental Activity) in Health Service practice in England and Wales prevents practitioners adopting a modern biological approach to caries control.

Up to this point, the scientific basis for caries control and practical details for delivery of caries control to the individual have been given. We now change tack and consider caries control in populations. In order to follow the health profiles in populations there is an important tool called epidemiology. This literally means ‘the study of what is upon people’. It is derived from Greek where ‘epi’ means upon or among and ‘demos’ is people (population). In other words, epidemiology is the study of the distribution (how often) various diseases occur and why they appear in well-defined populations. It deals with groups of people, not individuals. Data thus obtained are used in public health for developing and monitoring strategies for health care in populations. Moreover, it can tell how diseases are influenced by hereditary factors, by physical and social environments, and human behaviour. All this helps health authorities to develop appropriate preventive interventions and make these as cost-effective as possible. In this chapter, having introduced the concepts of epidemiology, examples of caries control in two populations and its assessment using epidemiological measurements is given. However, the use of epidemiology has already been described in Chapter 4, where Dean’s observations on the relationship between fluoride in water supplies, the resulting dental fluorosis, and the concomitant caries reduction are described (see Chapter 4). In a recording system of any disease it is important to have clear criteria for diagnosis. The following are important: ◆ How valid are the criteria of measurement? Do they record what they are intended to measure? ◆ How reliable are the criteria? Reliability is also covered by the terms reproducibility, and consistency. These terms imply that the same or different examiners can use the criteria in the same way on different occasions and obtain the same result. ◆ The criteria should be clear, simple, and objective. In other words robust. This is particularly important if manifestations of a disease are to be grouped in different categories of severity, as with dental caries.

Chapter 4 described caries control measures for everybody, a whole population approach. The emphasis was on oral hygiene, regularly disturbing the biofilm with fluoride toothpaste. The mode of action of fluoride was discussed in some detail to show that this therapeutic agent acts topically to interfere with the deand remineralizing processes and delaying lesion development. The relevance of minimizing sugar intake was discussed. The metabolism of sugar, by microorganisms in the biofilm, creates the acidic environment for demineralization. However, what more should be done for those presenting with active lesions? This chapter will consider how to find out why these patients are developing lesions. The chapter will then explore further oral hygiene measures that might be useful. It will question how fluoride might be boosted and their diet modified. Specific groups, such as babies and young children, those with erupting teeth, patients undergoing orthodontic treatment, and patients with dry mouths will be individually discussed. Finally, a section will discuss the difficulties of advising carers on helping those who can no longer care for themselves, either though illness, disability, old age, or dementia. The caries activity of any patient, child, or adult, is assessed at the first visit of the patient by noting how many lesions judged as active are present (both cavitated and non-cavitated) and where they are located (see Chapter 3). Please note, this assessment is mainly based on clinical assessment. Some companies produce a battery of chairside salivary tests, such as microbiological counts of specific microorganisms, but these are not needed. If the patient is coming for a regular check-up, a history of recent caries activity is available (number of lesions and fillings over the last 1–3 years). This information is most valuable. A yearly increment of one or more lesions detected clinically, would indicate a high rate of lesion formation and progression. Once a dentist has assessed an individual patient’s caries activity as high, an attempt should be made to identify the relevant risk factors for this patient. It is possible to interfere with and modify many of these factors, and thus arrest ongoing active lesions, or slow down the disease activity and diminish the rate of progression.

The first three chapters of this book have introduced the basics of what dental caries is and how to detect lesions. The next chapter will consider the concept of caries control and begins by explaining why throughout this book the preferred term is caries control, rather than prevention. Remember, the formation of the dental biofilm, and its metabolism is an ubiquitous natural process; it cannot be prevented. So: Question: Who is susceptible to caries lesion development? Answer: Everyone with teeth, from cradle to grave because the metabolism in the dental biofilm is an ubiquitous, natural process. Lesion development and progression, which may occur over time, are symptoms of the process. We should aim to control these processes so that the development of a clinically visible lesion is avoided. However, if clinical lesions develop and progress these symptoms can be arrested by controlling the environment. Thus, all patients with teeth should know how lesions may form and progress, and how to control this. Please note the emphasis on the patient. It is the patient who controls caries with the support and encouragement of the professional. The goals of medicine (and dentistry) are to promote and preserve health if it is impaired, to restore health, and minimize suffering and distress. These goals are embodied in the word ‘prevention’. It is agreed that, with dental caries, this is basically what the dental profession is doing—and has always been doing. In many ways this has become a mantra—the dentists rightly claim that they are conducting prevention when recommending the population to eat less sugar, use fluorides, brush teeth, and when lesions occur, drill and fill, in order to restore the dentition and reduce pain and discomfort. Unfortunately, when dentists go for restoration—without ensuring that the patient understands how to control further caries lesion development—they indirectly stimulate the repair cycle, which ultimately may lead to loss of teeth (see Chapter 5). Sometimes the filling may be described as ‘treatment’ to contrast it with ‘prevention’. The dentist is paid for fillings (treatment) and minimally rewarded for so-called prevention.

In the previous chapters, the point has been made that dental caries is controllable by the patient regularly disturbing the biofilm, the use of fluoride, especially in toothpastes, and a sensible, but not draconian diet. The success of these strategies depends on the patient, but patients may choose not to comply with the health advice given to them. Many know they should not smoke, should lose weight, and take more exercise, but choose not to alter their behaviour. Altering a patient’s behaviour may be key to caries control, and for this reason all members of the dental team should be interested in strategies to modify behaviour. Motivation is about unlocking the desire within another to make a useful change in behaviour. Good communication is one of the foundations for motivation. Compliance is not likely where patients do not understand, or cannot remember the message. However, people do not change their behaviour just because someone tells them, however clearly, that this is a good idea. Motivation comes from within and cannot just be instilled. It should also be remembered that motivation to change is something that comes gradually, with most people feeling ambivalent about change. Someone who is ambivalent may see a reason to change, but may also see a reason not to change. When we try to persuade someone who is ambivalent to change, the danger is they will resist, giving voice to the counter-argument as to why they cannot change. Actually, the best way to achieve change is if the patient, rather than the health professional, says why and how they should change. In other words, it is their idea and we are there to support it. Despite all these difficulties, good communication can make all the difference in achieving behaviour change and, for this reason, this chapter will now take a detour to discuss aspects of communication. Communication is made up of more than just the actual words used to convey information. The tone used conveys the speaker’s emotions and attitudes, and so-called non-verbal communication or body language can be just as important as the actual words.

The oral cavity is an open sink. The mucous membranes and teeth are constantly covered with a salivary film whose proteins adhere to all surfaces in the mouth. Saliva is not just a fluid flushing through the oral cavity, but a highly complex proteinaceous liquid that contains millions of microorganisms (bacteria). Depending on their different surface properties (different species have different surface proteins comprising their cell wall, which coat the surface of each cell) they stick to the salivary proteins at the surfaces of mucous membranes and teeth. These oral microorganisms comprise the endogenous flora of the mouth. They are living in symbiosis with the cells of the human body and comprise what is today called the metagenome. There are more bacteria covering all body surfaces in each individual than there are eukaryotic cells in the whole body. Eukaryotes store their DNA in a membrane ‘sac’ called the nucleus. Plants, fungi, and animals are eukaryotes, whereas bacteria are prokaryotes with no distinct nuclear compartment in which to store their DNA. Prokaryotes live in a variety of ecological niches. An occlusal fissure is an example of such a niche and so is an approximal space between neighbouring teeth, the gingival crevice, and periodontal pockets. Bacteria are astonishingly varied in their biochemical capabilities—in fact, more so than eukaryotic cells and each ecological niche may have a particular environment (different pH, inflammatory exudate, etc.), which will influence the microbial function and composition. Until recently, traditional bacteriological methods were used to isolate and culture microorganisms in the laboratory, but it was realized that only a few could be cultivated! DNA sequencing techniques (genomics) of populations of microorganisms from a variety of natural habitats (including the oral cavity) showed that most species have not been found by these traditional culturing techniques. According to some estimates, about 99% of prokaryotic species remain to be characterized. For this reason alone, it does not make sense to think that a particular ‘caries microorganism’ exists. There are also implications for the many attempts to find salivary microbial and biochemical biomarkers that might be used clinically to assess caries risk.

In Chapter 1 it was stressed that while all dental biofilms exhibit intense metabolic activity, only biofilms where a shift in metabolic activity towards an enhanced acid production over longer periods of time, will result in a net loss of mineral from the underlying tooth surface. The reflection or symptom of this is what can be detected with the naked eye and classified as the caries lesion on the tooth surface. It was pointed out that lesions may be active (if nothing changes in the oral environment, they will progress) or arrested (if nothing changes they will stay as they are). Thus, the things it is necessary to know in order to make an appropriate treatment decision are: ◆ Is a lesion present? This is detection of the lesion. ◆ Is the lesion judged to be active or arrested? This decision, adding the aspect of activity to detection, is diagnosis. ◆ Is the surface of the lesion intact or is a cavity present? If there is a cavity, can the lesion be cleaned by the patient? Diagnosis has been called a ‘mental resting place on the way to a treatment decision’. For instance, grading a lesion as active implies that the clinician considers that, if nothing is done, the demineralization will progress. Figure 3.1 is a decision tree showing how the diagnostic decision may guide the treatment. Thus, the diagnosis detects and excludes disease, assesses prognosis (considering the entire oral condition of the mouth), and forms the basis for the treatment decision. Lesions where the tooth surface is intact can be managed by the patient’s caries control measures. However, a cavity in a tooth may prevent access for the toothbrush. In addition, it may be unsightly and the tooth may be sensitive. These lesions may require restorations as a part of caries control. It is the duty of the professional to discuss with the patient whether any action is required in order to control lesion progression. Finally, the diagnosis should allow the clinical course of the disease to be monitored at subsequent visits.

At the start of this book it was commented that some dentists see restorative dentistry (fillings) as the treatment of dental caries. These dentists see prevention of caries as a separate issue. The authors profoundly disagree with this. The previous chapters have shown how dental caries develops and what it is, so in this chapter it is important to ask the question ‘with this knowledge in mind, what is the role of restorations (restorative dentistry) in caries control?’ Are restorations required or can the problem be solved by sealing all surfaces in the oral cavity—or at least those parts where surface irregularities (occlusal fissures, grooves, pits, etc.) may favour biofilm stagnation? Therefore, this chapter starts with a discussion of so-called fissure sealants. On occlusal surfaces, caries lesions may form at the entrance to the fissure because this complex morphology may be difficult to clean, particularly in the erupting tooth that is below the level of the arch and tends to be missed as the toothbrush swings by. Fissure sealants cover the fissures with a flowable resin or highly viscous glass ionomer cement, so that they are easier to clean. Their effectiveness has been proved in many studies. When first introduced in developed nations, all molar surfaces were recommended for sealing to avoid caries development and the need for fillings. This ‘sealing all teeth’ policy would now be totally incorrect for two reasons: ◆ Caries can be controlled by cleaning alone. ◆ Many of these surfaces will never develop lesions, and this automatic sealing approach is over treatment and not cost-effective. The indications for fissure sealing are: ◆ Active fissure caries has been diagnosed, but attempts at caries control have not arrested lesion progression. ◆ Occlusal surfaces are often highly irregular, and filled with grooves and fissures, and the patient or parent either cannot, or will not, remove plaque effectively. This is particularly important in the erupting molar. This surface is particularly at risk of lesion development and progression because permanent teeth can take 6–12 months to erupt; indeed, third molars may take several years.

A pain-free, functioning, and good-looking dentition for a lifetime seems a reasonable goal! Is this what dentists do? An advertisement for a North American dental practice recently suggested that dentists practising general dentistry provide amalgam and composite fillings, sealants, cosmetic dentistry, pulp and root canal treatment, crown and bridges, dentures, and dental implants. Moreover, they do minor oral surgery, gum disease treatment, and occasionally temporomandibular joint (TMJ) therapy, tobacco cessation, and nutrition counselling. The topics listed in the first sentence comprise the daily work in general dentistry, but do you realize that 85% of these are a direct consequence of dental caries? Yet dental caries is not mentioned as the main reason for most dental treatments. Restorative treatment is the focus of dentistry. The disease dental caries is the only disease which has been combatted with metals and composites for more than a century. Some 50 years ago the concept of prevention became fashionable. Now restorative treatment was described as ‘secondary prophylaxis’ because it was considered that once the inevitable dental caries had occurred, it had to be treated (i.e. restored) to prevent further break down of the teeth and the dentition. Therefore, it is not surprising that the most time in the dental curriculum is devoted to the many skilled restorative procedures. These have to be conducted in a moist, slippery, small, and moving oral cavity attached to a person who may find the procedure unpleasant! No wonder it is difficult to perform intra-oral restorative work of high quality as part of oral rehabilitation, and no wonder so much time in the curriculum is devoted to these aspects. However, supposing it was possible to prevent or control the disease so that restorations are reduced to a minimum? This control of caries is what this book is about! Seven chapters present the essentials of what is known about dental caries. The observations will be based on current scientific evidence. This is a hands-on book, which means that what is suggested and observed should have immediate implications for how patients may be treated.

Whether deciduous teeth should be restored has caused controversy for at least 150 years and the argument rages on. Dental caries is a controllable process. The role of operative dentistry and restorations, as far as caries control is concerned, is to make cavitated, uncleansible lesions accessible to plaque control. However, deciduous teeth are exfoliated and perhaps non-operative treatments (plaque control, fluoride, diet) are all that are required to take cavitated teeth pain-free to exfoliation. Are such techniques child-friendly, obviating the need for anaesthesia or the use of handpieces? Alternatively, are they wanton neglect? This paper is written by a cariologist who never treated children, to present alternative managements and rehearse these arguments from a cariological perspective.Clinical Relevance: This paper might serve as a discussion document for a group of dentists deciding practice policy with regard to the management of caries in deciduous teeth.

The caries process is the ubiquitous, natural metabolism in the biofilm that causes numerous fluctuations in pH. The interaction of this biofilm with the dental tissues may result in a caries lesion. However, lesion formation and progression can be controlled, particularly by disturbing plaque regularly with a fluoride containing toothpaste. This paradigm implies that everyone with teeth is at risk to lesion development. Treatment of caries is principally non-operative, involving plaque control, fluoride and a sensible diet. Operative dentistry repairs un-cleansable cavities and is part of plaque control. A diagnosis is a mental resting place on the way to a treatment decision. The relevant diagnostic features with respect to caries are lesion activity (active lesions require active management) and un-cleansable cavities. When teaching undergraduates, it is important that they are credited for the non-operative treatment of caries as well as for operative dentistry. This is equally important in dental practice where an appropriate skills mix of the dental team is required to deliver dental health cost-effectively. Training more dentists may be an expensive mistake as far as disease control is concerned. It is ironic that dentists make most money from operative care and specialist treatment when disease control could be delivered relatively cheaply. The key to dental health is regular and effective plaque control with a fluoride containing toothpaste, from cradle to grave.

Caries is a ubiquitous, natural process occurring in the biofilm. Lesion formation can be controlled by plaque control, fluoride and a sensible diet. Diagnosis is a mental resting place for a treatment decision. Active lesions require active management, including non-operative measures to arrest the lesion, supplemented with operative dentistry to facilitate cleaning of cavities. The diagnosis of active lesions is the best measure of caries risk and should determine recall intervals. The paper describes a clinical sequence of oral hygiene instruction, followed by a clinical examination of clean, dry teeth and then fluoride varnish application.

Aim: A randomised, controlled, double-blind, clinical trial was conducted to investigate the effect of a chlorhexidine acetate/xylitol gum (ACHX) on the plaque and gingival indices of 111 elderly occupants in residential homes. A gum containing xylitol alone (X) and a no gum (N) group was included. Participants’ opinions about chewing gum were also investigated. Methods: Subjects chewed 2 pellets, for 15 min, 2× daily for 12 months. Results: In the ACHX group, the plaque and gingival indices significantly decreased (p

Substantial pH fluctuations within the biofilm on the tooth surface are a ubiquitous and natural phenomenon, taking place at any time during the day and night. The result may be recordable in the dental tissues at only a chemical and/or ultrastructural level (subclinical level). Alternatively, a net loss of mineral leading to dissolution of dental hard tissues may result in a caries lesion that can be seen clinically. Thus, the appearance of the lesion may vary from an initial loss of mineral, seen only in the very surface layers at the ultrastructural level, to total tooth destruction. Regular removal of the biofilm, preferably with a toothpaste containing fluoride, delays or even arrests lesion progression. This can occur at any stage of lesion progression, because it is the biofilm at the tooth or cavity surface that drives the caries process. Active enamel lesions involve surface erosion and subsurface porosity. Inactive or arrested lesions have an abraded surface, but subsurface mineral loss remains, and a true subsurface remineralization is rarely achievable, because the surface zone acts as a diffusion barrier. The dentin reacts to the stimulus in the biofilm by tubular sclerosis and reactionary dentin.

The metabolic activity in dental plaque, the biofilm at the tooth surface, is the driving force behind any loss of mineral from the tooth or cavity surface. The symptoms of the process (the lesion) reflect this activity and can be modified by altering the biofilm, most conveniently by disturbing it by brushing with a fluoride-containing toothpaste. The role of operative dentistry in caries management is to restore the integrity of the tooth surface so that the patient can clean. Thus, the question, ‘how clean must a cavity be before restoration?’ may be irrelevant. There is little evidence that infected dentine must be removed prior to sealing the tooth. Leaving infected dentine does not seem to result in caries progression, pulpitis or pulp death. However, some of the bacteria survive. What is their fate and if they are not damaging, why is this?

One aim of the present laboratory study was to determine whether a visual scoring system (ERK) developed for occlusal caries could be applied to approximal lesions. A new histological technique (autofluorescence, AF) recognises dentine that is soft and would be removed with an excavator during operative treatment. A second aim was to investigate the relationship between the visual scoring system (ERK) and AF of dentine both occlusally and approximally. The sample comprised 93 extracted teeth chosen to represent the range of visual scores on approximal and occlusal surfaces. After sectioning through the investigation site, the cut faces were examined in a stereomicroscope and the depth of demineralization was scored. Autofluorescence was viewed with a confocal laser scanning microscope. Results showed reasonable correlation between the visual scores and the stereomicroscope histological evaluations for occlusal surfaces and non-cavitated approximal surfaces. However, cavitated approximal surface lesions were less advanced histologically than cavitated occlusal carious lesions. The AF technique indicated that several lesions with intact surfaces would have had soft, excavatable dentine, whereas several with microcavities would not.

OBJECTIVES: To determine the effects of a medicated chewing gum on the oral health of frail older people. DESIGN: A controlled, double-blind trial using three groups based on random allocation of residential homes. SETTING: Sixteen residential homes in West Hertfordshire, England. PARTICIPANTS: One hundred eleven dentate subjects aged 60 and older who completed the 12-month study. INTERVENTION: Subjects were assigned to a chlorhexidine acetate/xylitol gum (ACHX) group, a xylitol gum (X) group, or a no-gum (N) group. Subjects in the gum groups chewed two pellets for 15 minutes twice daily for 12 months. MEASUREMENTS: Primary outcome measures were salivary flow rate, denture debris score, prevalence of angular cheilitis, and denture stomatitis; secondary outcome measures were salivary levels of caries-associated microorganisms. A single examiner, who was blinded to group allocation, made all measurements at baseline before gum usage and at subsequent examinations after 3, 6, 9, and 12 months. Separate analyses were performed for subjects with dentures. RESULTS: Subjects in the three groups were similar in most of their baseline characteristics. The stimulated whole saliva flow rate ± standard deviation increased significantly for the ACHX (1.4 ± 0.7 mL/min) and X (1.6 ± 0.9 mL/min) groups (P < .01) over baseline (ACHX = 0.9 ± 0.6 mL/min, X = 0.8 ± 0.6 mL/min) and N group levels (0.6 ± 0.9 mL/min). The levels of mutans streptococci, lactobacilli, and yeasts significantly increased (P < .05) in the X and N groups. Denture debris status was significantly lower in the ACHX and X groups than at baseline or in the N group (P < .01). The reductions of 91% and 75% in denture stomatitis and angular cheilitis prevalence, respectively, that occurred in the ACHX group were significantly greater (P < .01) than the reductions in the X group (denture stomatitis 62%, angular cheilitis 43%). Prevalence of denture stomatitis and angular cheilitis were not significantly changed in the N group. CONCLUSION: The use of a medicated chewing gum significantly improved oral health in older occupants of residential homes. Chewing gums should be considered as a potential adjunct to other oral hygiene procedures in older subjects.

OBJECTIVES To investigate the relationship between the oral hygiene practices of dentate elderly people living in residential homes, their requests for assistance and their oral health status. METHODS 164 people (81.2+/-7.4 years) participated in an interview and oral examination, and provided a stimulated saliva sample. RESULTS The mean number of coronal decayed surfaces (CDS) was 2.4+/-5.9, stimulated salivary levels (log(10)cfu/ml) of mutans streptococci, lactobacilli and yeasts were 1.6+/-2.1, 3.0+/-2.2, 2.1+/-1.7, respectively, and 53% had root decayed surfaces (RDS). Plaque (PI) and gingival (GI) Indices were 2.3+/-0.7 and 1.6+/-0.4 and denture debris scores (DDS) were high. 31% of the population cleaned their mouths twice daily without requesting help and they had significantly fewer yeasts, RDS, restorations on root surfaces, lower PI, GI (P

Occlusal caries now accounts for most of the lesions in children aged 8–15 years. This paper presents a ranked visual scoring system for occlusal caries diagnosis. It relates the clinical appearance of the lesion to its activity, the level of infection of the dentine and the histopathology. The appropriate management for each score is suggested.

A systematic review of the diagnosis of dental caries was produced before the conference. It did not include the diagnosis of secondary or recurrent caries. This was a wise decision because what little literature exists on the subject potentially clouds the issue. Diagnosis is a mental resting place on the way to a treatment decision. A vital part of caries diagnosis is to decide whether a lesion is active and rapidly progressing or already arrested. This information is essential to plan logical management. However, lesion activity should be judged in the patient. Thus, research on the diagnosis of secondary caries must be carried out in vivo and this usually precludes histological validation. Even if such validation is possible, it has its own problems, particularly in distinguishing recurrent from residual caries. The diagnosis of secondary caries is very important since so many restorations are replaced because dentists think there is a new decay. It will be important to establish valid criteria for the diagnosis of active secondary caries, which will be facilitated by the suggestion that secondary caries is no different from primary caries except that it occurs next to a filling. This implies that it can be seen clinically and on a radiograph, next to a restoration.

A clinical study was carried out to assess relationship between the presence of approximal cavitation, the radiographic depth of the lesion, the site–specific gingival index and the level of infection of the dentine. Adult patients assessed as needing operative treatment and presenting with approximal lesions visible in the outer third of dentine on bite–wing radiographs were included in the study. Direct lesion depth measurements were recorded from the radiographs and the site–specific gingival index adjacent to the lesion was noted. The presence or absence of a cavity was recorded on an impression following tooth separation. During operative treatment samples of dentine were taken on entry to the lesions to ascertain the level of infection of the dentine. Visual evaluation of 54 successfully recorded impressions revealed that 85% were cavitated. Cavitated lesions were found to have higher site–specific gingival index scores compared to non–cavitated lesions (p = 0.03). The probability of cavitation was greater for lesions >0.5 mm from the enamel–dentine junction on bite–wing radiographs (p

“The complete divorcement of dental practice from studies of the pathology of dental caries, that existed in the past, is an anomaly in science that should not continue. It has the apparent tendency to make dentists mechanics only.”

Objective The objectives of this study were: to evaluate carers' knowledge of oral health; to provide a high quality, consistent, oral health training programme for carers in residential homes; to evaluate the quality of this programme by examining both carers' changes in knowledge and any changes in carers' behaviour as reported by residents and to assess any changes in the oral health of the elderly residents after one year. Design A cross-sectional, multi-centre study using a carer training programme, evaluated by both a questionnaire conducted with carers and residents and oral examination of residents. Setting In August 1996, 20 (20%) of the residential/nursing homes, in West Hertfordshire were chosen at random and all managers contacted and offered an oral examination for all their residents. Ten (10%) of the homes were also offered an oral health training programme for their carers. Eighteen homes accepted the oral examination for all consenting residents and 7 of the 10 homes offered accepted the carer training. Subjects Thirty-nine carers from 7 of the residential homes attended an oral health training course and 213 elderly residents in the 18 homes were examined both at baseline and after 12 months. Results Carers' baseline knowledge about oral health was poor; the oral health training programme was enjoyed and their knowledge gain after one week was high. However, the elderly residents perceived no change in the oral care given by carers either after one week or after one year and there was no measurable improvement in the oral health of residents after carer training, except for an increase in filled coronal surfaces. Few of the carers originally trained were still working in the same residential homes after one year. Conclusion Although the carer training programme was well received, no changes in oral health practice resulted. Barriers to practice of oral care by carers remained and training, even when including practical skills, evaluation by peers and a high knowledge gain, failed to reduce these barriers.

Background: The treatment of deep dental decay has traditionally involved removal of all the soft demineralized dentine before a filling is placed. However, this has been challenged in three groups of studies which involve sealing soft caries into the tooth. The three main groups either remove no caries and seal the decay into the tooth, remove minimal (ultraconservative) caries at the entrance to a cavity and seal the remaining caries in, or remove caries in stages over two visits some months apart to allow the pulp time to lay down reparative dentine (the stepwise excavation technique). Objectives: To test the null hypothesis of no difference in the incidence of damage or disease of the nerve of the tooth (pulp), progression of decay and longevity of restorations irrespective of whether the removal of decay had been minimal (ultraconservative) or complete. Search strategy: The Cochrane Oral Health Group Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, PubMed and EMBASE databases were searched. The reference lists in relevant papers were checked. Selection criteria: Randomized controlled trials and controlled clinical trials comparing minimal (ultraconservative) caries removal with complete caries removal in unrestored permanent and deciduous teeth. Data collection and analysis: Outcome measures recorded were exposure of the nerve of the tooth (pulp) during caries removal, patient experience of symptoms of pulpal inflammation or necrosis, progression of caries under the filling, time until the filling was lost or replaced. Due to the heterogeneity of the included studies the overall estimate of effect was calculated using a random-effects model. Main results: Four studies met the inclusion criteria; two stepwise excavation studies and two ultraconservative caries removal studies. Partial caries removal in symptomless, primary or permanent teeth reduces the risk of pulp exposure. We found no detriment to the patient in terms of pulpal symptoms in this procedure and no reported premature loss or deterioration of the restoration. Authors’ conclusions: The results of this systematic review reject the null hypothesis of no difference in the incidence of damage or disease of the nerve of the tooth (pulp) irrespective of whether the removal of decay had been minimal (ultraconservative) or complete and accepts the null hypothesis of no difference in the progression of decay and longevity of restorations. However, the number of included studies is small and differ considerably. Partial caries removal is therefore preferable to complete caries removal in the deep lesion, in order to reduce the risk of carious exposure. However, there is insufficient evidence to know whether it is necessary to re-enter and excavate further but studies that have not re-entered do not report adverse consequences.

Chewing gums may be suitable vehicles for the delivery of xylitol (X) and chlorhexidine acetate (CHX), both of which can aid oral health. The aim of this study was to determine the clinical effectiveness of chewing gums containing X or a combination of X and CHX in a double-blind, randomised, cross over, 5-day clinical trial, with a 9-day washout period in a group of participants over 40 years old. After professional tooth cleaning, 8 subjects (mean age 51.3+/-10.4 years) used in a random order 2 pieces of ACHX (a liquorice flavoured CHX/X) gum, 2 pieces of BCHX (a chocolate mint flavoured CHX/X), 2 pieces of X (a liquorice flavoured X gum) and 1 piece of ACHX. Gums were chewed 2x daily for 15 min and volunteers refrained from all other oral hygiene procedures. Data were analysed using Friedman nonparametric analysis of variance. Plaque indices for chewing 2 pieces of ACHX gum (0.78+/-0.15) and BCHX gum (0.52+/-0.15) were significantly lower (p

It is conventionally taught that the carious lesion in dentin undermines the enamel due to lateral spread of the lesion at the enamel–dentin junction (EDJ). The aim of the present study was to challenge this hypothesis by testing an alternative hypothesis, that lateral spread is related to advanced lesions where the dentin is infected. Selected points in the groove–fossa system of 100 unrestored occlusal surfaces were examined and the teeth divided into five groups (scores 0–4) depending on the clinical appearance of the lesion. Teeth were sectioned through these sites and texture of the dentin was assessed by probing. Colour slides of the section face with the more extensive changes in the dentin were projected and the dimensions of the lesions at the EDJ were assessed by three examiners on two separate occasions. Inter- and intra-examiner reproducibility was assessed and found acceptable. Results showed that in 47 teeth demineralisation had not reached the EDJ. In the remaining teeth the presence or absence of lateral spread of the lesion at the EDJ was related to the clinical features of the lesion. Lateral spread was rarely found in lesions with an apparently intact enamel surface (scores 0–2). However, 32% of sites with microcavitation (score 3) and 63% of sites with obvious cavitation (score 4) showed lateral spread. Of those 31 sections which were judged to have soft dentin, 80% had lateral spread. In conclusion, the phenomenon of lateral spread of caries at the EDJ is related to advanced lesions with cavity formation where the dentin is soft and infected.

This laboratory study of 100 occlusal surfaces investigated the reproducibility and accuracy of a visual ranked caries scoring system, an electronic caries scoring system (ECM) using a continuous conductance scale, and a radiographic ranked caries scoring system. Histological examination of the teeth served as a gold standard to validate the ability of each system to assess lesion depth and predict softened, demineralized dentine. After training, 3 examiners carried out each scoring system on two separate occasions. Kappa values for visual, ECM and radiographic ranked scoring systems showed good inter- and intra-examiner reproducibility levels and acceptable limits of agreement for ECM readings. When scoring systems were tabulated against histological scores there was a high correlation between the visual and ECM methods and lesion depth in both enamel and dentine, but radiographic examination could not detect enamel caries. When compared to the histological scoring, the Spearman correlation coefficients for the visual scoring ranged between 0.87 and 0.93, for the ECM between 0.80 and 0.85 and for the radiographic scoring system between 0.76 and 0.78. No tooth scored as visually sound had histological evidence of dentine caries. Soft dentine corresponded to demineralization involving the middle third of the dentine or more which was related to visual cavity formation or an ECM reading above 9 (score 3 or 4). The radiograph was an excellent predictor of soft dentine. In conclusion, the new visual system appears promising, but takes time to learn. The reproducibility and accuracy for the ECM is acceptable while radiographs miss early occlusal lesions.

There has been renewed interest in the electronic diagnosis of occlusal caries using measurement of conductance or impedance. One of two previously manufactured electronic caries detectors (the Vanguard electronic caries detector, Massachusetts Manufacturing Corporation, Cambridge, Mass., USA) had a probe tip with an integral air supply. Airflow is essential for removing superficial moisture and preventing surface conduction to the gingival margin. The aim of this study was to determine the effect of airflow on electronic diagnosis of occlusal caries using a prototype electronic caries meter (ECM II. LODE, Groningen, The Netherlands) fitted with a flow meter. Stable conductance readings were taken at 76 discrete sites on 32 extracted teeth with no visible signs of cavitation, at 3 airflows: 5, 7.5 and 10 litres/min. The stable conductance scale was a continuous scale from -0.45 to 13.25 and set by the manufacturer. Histological validation was carried out on macroradiographs of sections cut to include each sample site. The histological picture was compared with the stable conductance readings taken at various airflows. Sensitivity and specificity were calculated using different conductance readings to differentiate sound and carious sites, and receiver operating characteristic (ROC) curves constructed. Of the sites, 32% had enamel and dentine caries and 33% had enamel caries. The ROC curves showed airflow to be highly relevant. An airflow of 5 litres/min was shown to be inadequate and led to large numbers of false-positive diagnoses. A minimum airflow of 7.5 litres/min was required to achieve optimum sensitivity (92%) and specificity (87%) for dentine caries diagnosis.

A prototype electronic caries meter (ECM II; LODE, Groningen. The Netherlands) was designed to deliver a conductance reading when the reading had remained stable for 3 consecutive seconds. The aim of this study was to determine whether this type of stable conductance reading was optimal for caries diagnosis. The ECM II was connected to a graphic recorder which enabled the continuous resistance to be recorded. The graphic recording was calibrated using a standard, variable resistance box. Stable conductance readings were taken for 76 sites on 32 extracted teeth with no visible sign of cavitation at an airflow of 7.5 l/min. Simultaneous graphic recording of resistance was continued for 10 s and cumulative resistance measurements were calculated by adding the resistance values at 1-second intervals. Histological validation of caries status was carried out on macroradiographs of sections cut to include sample sites. The histological picture was compared with the stable conductance reading and the cumulative resistance value for each site. Sensitivity and specificity values were calculated by randomly choosing stable conductance and cumulative resistance values to differentiate sound and carious sites. The results were presented as a series of receiver operating characteristics (ROC) curves and the optimum sensitivity and specificity values determined. 33% of sites had enamel caries and 32% had enamel and dentine caries. Results showed that both stable conductance readings and cumulative resistance measurements gave high and comparable sensitivity and specificity values for the diagnosis of dentine caries (sens. 92%, spec. 87% and sens. 88%, spec. 81%, respectively). However, when intra-examiner reproducibility was checked, stable conductance readings were more repeatable and achieved in shorter clinical time. In conclusion, stable conductance readings appear to be the most suitable for occlusal caries diagnosis.

To compare diagnostic yield in caries diagnosis from D- and E-speed films.A laboratory study.A UK dental school between 1992 and 1994.96 extracted teeth containing approximal and occlusal lesions, but representing a low caries prevalence sample, were set in occluding dental arches. Bitewing radiographs were taken and interpreted by 5 examiners for the presence or absence of caries. Each examiner was also asked which film image he or she subjectively liked best.The teeth were subsequently sectioned and histologically examined to validate diagnostic decisions.For all film types the percentage of lesions with caries histologically in dentine correctly identified radiologically (sensitivity) was low (approximal caries 8-22%; occlusal caries 0-30%). The number of sound dentine sites correctly identified (specificity) was high (approximal caries 98-100%; occlusal caries 79-100%). There were no significant differences between D- and E-speed films. Sensitivity was unaffected by each examiner's subjective preference for a particular film. The variation in sensitivity of diagnosis was due to differences between examiners.The reluctance of many GDPs to use E-speed film because they 'do not like the image' cannot be endorsed or supported. Both E-speed film types examined can be recommended for use in general practice.

Background The management of dental caries has traditionally involved removal of all soft demineralised dentine before a filling is placed. However, the benefits of complete caries removal have been questioned because of concerns about the possible adverse effects of removing all soft dentine from the tooth. Three groups of studies have also challenged the doctrine of complete caries removal by sealing caries into teeth using three different techniques. The first technique removes caries in stages over two visits some months apart, allowing the dental pulp time to lay down reparative dentine (the stepwise excavation technique). The second removes part of the dentinal caries and seals the residual caries into the tooth permanently (partial caries removal) and the third technique removes no dentinal caries prior to sealing or restoring (no dentinal caries removal). This is an update of a Cochrane review first published in 2006. Objectives To assess the effects of stepwise, partial or no dentinal caries removal compared with complete caries removal for the management of dentinal caries in previously unrestored primary and permanent teeth. Search methods The following electronic databases were searched: the Cochrane Oral Health Group's Trials Register (to 12 December 2012), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 11), MEDLINE via OVID (1946 to 12 December 2012) and EMBASE via OVID (1980 to 12 December 2012). There were no restrictions regarding language or date of publication. Selection criteria Parallel group and split-mouth randomised and quasi-randomised controlled trials comparing stepwise, partial or no dentinal caries removal with complete caries removal, in unrestored primary and permanent teeth were included. Data collection and analysis Three review authors extracted data independently and in triplicate and assessed risk of bias. Trial authors were contacted where possible for information. We used standard methodological procedures exacted by The Cochrane Collaboration. Main results In this updated review, four new trials were included bringing the total to eight trials with 934 participants and 1372 teeth. There were three comparisons: stepwise caries removal compared to complete one stage caries removal (four trials); partial caries removal compared to complete caries removal (three trials) and no dentinal caries removal compared to complete caries removal (two trials). (One three-arm trial compared complete caries removal to both stepwise and partial caries removal.) Four studies investigated primary teeth, three permanent teeth and one included both. All of the trials were assessed at high risk of bias, although the new trials showed evidence of attempts to minimise bias. Stepwise caries removal resulted in a 56% reduction in incidence of pulp exposure (risk ratio (RR) 0.44, 95% confidence interval (CI) 0.33 to 0.60, P < 0.00001, I2 = 0%) compared to complete caries removal based on moderate quality evidence, with no heterogeneity. In these four studies, the mean incidence of pulp exposure was 34.7% in the complete caries removal group and 15.4% in the stepwise groups. There was also moderate quality evidence of no difference in the outcome of signs and symptoms of pulp disease (RR 0.78, 95% CI 0.39 to 1.58, P = 0.50, I2 = 0%). Partial caries removal reduced incidence of pulp exposure by 77% compared to complete caries removal (RR 0.23, 95% CI 0.08 to 0.69, P = 0.009, I2 = 0%), also based on moderate quality evidence with no evidence of heterogeneity. In these two studies the mean incidence of pulp exposure was 21.9% in the complete caries removal groups and 5% in the partial caries removal groups. There was insufficient evidence to determine whether or not there was a difference in signs and symptoms of pulp disease (RR 0.27, 95% CI 0.05 to 1.60, P = 0.15, I2 = 0%, low quality evidence), or restoration failure (one study showing no difference and another study showing no failures in either group, very low quality evidence). No dentinal caries removal was compared to complete caries removal in two very different studies. There was some moderate evidence of no difference between these techniques for the outcome of signs and symptoms of pulp disease and reduced risk of restoration failure favouring no dentinal caries removal, from one study, and no instances of pulp disease or restoration failure in either group from a second quasi-randomised study. Meta-analysis of these two studies was not performed due to substantial clinical differences between the studies. Authors' conclusions Stepwise and partial excavation reduced the incidence of pulp exposure in symptomless, vital, carious primary as well as permanent teeth. Therefore these techniques show clinical advantage over complete caries removal in the management of dentinal caries. There was no evidence of a difference in signs or symptoms of pulpal disease between stepwise excavation, and complete caries removal, and insufficient evidence to determine whether or not there was a difference in signs and symptoms of pulp disease between partial caries removal and complete caries removal. When partial caries removal was carried out there was also insufficient evidence to determine whether or not there is a difference in risk of restoration failure. The no dentinal caries removal studies investigating permanent teeth had a similar result with no difference in restoration failure. The other no dentinal caries removal study, which investigated primary teeth, showed a statistically significant difference in restoration failure favouring the intervention. Due to the short term follow-up in most of the included studies and the high risk of bias, further high quality, long term clinical trials are still required to assess the most effective intervention. However, it should be noted that in studies of this nature, complete elimination of risk of bias may not necessarily be possible. Future research should also investigate patient centred outcomes.

The diagnosis of occlusal caries depends upon the correct identification of demineralised enamel and dentine. However, tissue demineralisation precedes bacterial infection so that dentine may be demineralised but uninfected. The presence of a bacterial infection of dentine may be a more relevant factor to be considered when planning to restore a carious lesion. The aim of this clinical study was to validate three techniques for the diagnosis of occlusal caries as demineralised tissue and as infected demineralised tissue during cavity preparation. The study sample was 82 non-cavitated occlusal lesions, judged by various dentists to be in need of operative care. The diagnostic techniques used by the single operator were vision, bitewing radiography and electronic caries diagnosis. The validating techniques were a caries detector dye to stain demineralised tissue, microbiological sampling to determine the level of infection of the dentine and clinical assessment of the dentine at operation. The caries detector dye showed demineralised dentine in 96% of the referred lesions. This demineralisation was reliably predicted by the electronic readings. However, the dentine samples from many teeth yielded only small numbers of bacteria indicating no, or only a very low level of bacterial infection. Neither vision nor electronic readings reliably predict heavily infected dentine. Radiographic evidence of dentine demineralisation was significantly associated with heavily infected dentine and this dentine was soft and wet at operation.

Clinical and radiographic diagnosis of occlusal caries is difficult. Resistance measurements in pits and fissures have shown better sensitivity compared with the more conventional methods of diagnosis. Two machines have been manufactured for this purpose: the Vanguard and the Caries Meter L. The aims of this study were to calibrate the readouts of these machines against a variable standard resistance box and use the Vanguard to compare readings taken in vivo and in vitro after extraction of the teeth. The diagnostic accuracy of clinical, radiographic, Vanguard and Caries Meter L diagnoses were also assessed. One hundred occlusal sites in 40 teeth of 20 patients were investigated in vivo with the Vanguard, noting clinical and radiographic appearances. The teeth were then extracted and the Vanguard readings repeated in vitro, together with Caries Meter L readings. The in vivo/in vitro comparison between Vanguard readings showed excellent reproducibility (Cohen's Kappa = 0.80). The sensitivity and specificity for the different examination techniques at the enamel level of diagnosis were 27% and 89% for visual, 6% and 100% for radiographic, 81% and 78% for the Vanguard and 74% and 74% for the Caries Meter L. In conclusion, this study supports the renewed interest in resistance measurements as a diagnostic technique and indicates that the in vitro model used gives results comparable to those in vivo.

This paper describes the use of a questionnaire designed to enable students to comment on aspects of the teaching they received from their tutor during the preclinical course in Conservative Dentistry. The information was subsequently used by the teachers themselves, to modify their performance.

Secondary caries is difficult to diagnose accurately. The purpose of this laboratory study was to investigate various non-invasive clinical and radiographic criteria which might predict the presence of carious dentine beneath the margin of the filling. A total of 331 sites, each 3 mm in length on the tooth restoration margin, were selected on 112 extracted and filled teeth. Thirty of these sites showed obvious carious cavities. Ditching was apparent in a further 70 sites, while 231 sites were clinically intact. Staining of the margin of the filling was recorded and radiographs were taken of posterior teeth. Restorations were then removed and the enamel-dentine junction (EDJ) immediately below the sites was examined for its consistency (hard/soft) and colour (stained/stain-free). Results showed that staining around a filling is not a reliable predictor of softening or discolouration of the dentine beneath. A clinical carious cavity and radiographic evidence of demineralisation indicate soft and discoloured dentine and should trigger operative intervention, while ditching alone should not.

Caries is a ubiquitous, natural process occurring in the biofilm. The interaction of the biofilm with the dental tissues may result in a caries lesion, the reflection of the process being the consequence that can be seen. However, lesion formation and progression are not inevitable because the process in the biofilm can be controlled by plaque control, fluoride and a sensible diet. This paper summarizes caries control in note form and it questions how these measures are to be carried out under the current Unit of Dental Activity payment system used within the NHS Dental Services in England and Wales.Caries control is the non-operative management of the ubiquitous, natural process in the biofilm so that lesions do not form, or established lesions are arrested. This paper seeks to present these caries control measures in note form as checklists to aid the dental team.

The diagnosis of occlusal caries is an integral part of an epidemiologist's task, whether carrying out cross-sectional national caries prevalence surveys to assist with planning and the evaluation of service provision, or clinical trials of caries preventive agents. Similarly, the clinician also carries out this same overall diagnostic procedure in order to plan care for individual patients, although he/she will usually have access to improved facilities and diagnostic aids. This paper reviews the different problems now being encountered by both epidemiologists and clinicians in the face of changes in the presentation of the disease at this site and the qualifications which should now be appreciated when extrapolating from the results of surveys employing comparatively gross criteria. It explores recent developments in diagnostic aids and makes suggestions as to how further information might be obtained in future which would aid the valid comparison of diagnoses made by these two groups of dentists.

During cavity preparation conventional tactile and optical criteria are used to assess the caries status of the enamel-dentine junction, cavity preparation being considered complete when this area is hard to a sharp probe and stain free. In the present study 201 cavities were prepared under rubber dam. When caries removal was considered complete using the conventional tactile and optical criteria, a caries detector dye (1% acid red in propylene glycol), which is claimed to stain 'infected' tissue red, was applied. Fifty-two per cent of cavities showed caries dye stain in some part of the enamel-dentine junction. Subsequent microbiological sampling of dye-stained and dye-unstained sites resulted in the recovery of low numbers of bacteria and revealed no difference in the level of infection of the two sites. It is concluded that the conventional tactile and optical criteria are satisfactory assessments of the caries status of tissue during cavity preparation and that subsequent use of a caries detector dye on hard and stain-free dentine will result in unnecessary tissue removal.