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Amelogenesis, the intricate process governing enamel formation, is susceptible to a range of genetic, systemic, and environmental influences, resulting in distinct developmental defects of enamel (DDE), such as molar incisor hypomineralisation (MIH), enamel hypoplasia, dental fluorosis, and amelogenesis imperfecta (AI). This chapter aims to provide a comprehensive overview of amelogenesis and DDE, establishing correlations between histopathological findings and clinical manifestations. MIH, a qualitative enamel defect, occurs during the mineralisation and maturation phases, affecting first permanent molars and eventually incisors. Diagnostic challenges in MIH arise from the disorder's unique features, including variable tooth involvement and severity, influenced by a complex interplay of genetic, systemic, and environmental factors. Enamel hypoplasia, a quantitative defect, manifests in any tooth during enamel matrix secretion. Etiological factors include local, systemic, environmental, and genetic influences, with variable enamel matrix abnormalities depending on the stage of amelogenesis when aggression occurred. Dental fluorosis, a toxicological concern from chronic and excessive fluoride exposure, affects ameloblasts and compromises crystal growth of the homologous teeth during enamel development. Lastly, AI, an inherited condition, encompasses diverse phenotypes in enamel development. AI phenotypes, whether hypoplastic or hypomineralised, entail mutations in genes, such as AMELX, ENAM, MMP20, KLK4, WDR72, FAM83H, C4ORF26, amelotin, GPR68, and ACPT. Diagnosing AI involves considering family history and clinical observation. In conclusion, navigating the intricacies of amelogenesis, from MIH to AI, underscores the critical importance of accurate diagnosis for proper clinical management of DDE., (© 2024 S. Karger AG, Basel.)

In recent decades, dentistry has developed significantly in all areas. While in the past, caries was mainly treated operatively, the today's management has shifted toward noninvasive, minimal invasive, and, only if needed, invasive treatment options. Aiming at enabling the most noninvasive or conservative treatment option requires early caries detection, which, however, remains challenging. The progression of early or noncavitated caries lesions can nowadays be successfully controlled, as well as lesions arrested by oral hygiene procedures combined with the use of fluorides, sealants, or resin infiltration. Methods such as near-infrared light transillumination, fibre-optic transillumination, digital fibre-optic transillumination, laser fluorescence, or quantitative light fluorescence measurements were introduced in the dental market to provide X-ray-free caries detection, assessment, and monitoring. For approximal surfaces that are not directly visible, bitewing radiography is still the standard in detecting caries lesions. The use of artificial intelligence has become the most recent technological aid for the detection of caries lesions on bitewing radiographs and clinical images and has to be understood as an emerging technology, which requires extensive research in the future. The aim of this chapter is to give an overview of different possibilities to detect coronal caries lesions and suggestions of how to improve this process., (© 2023 S. Karger AG, Basel.)

Untreated dental caries is the most prevalent disease worldwide. Development of caries is associated with the intake of sugar. The microorganisms utilize the sugar and create an acidic environment, which results in mineral loss. The appropriate use of fluoride is associated with a decline of caries. Another approach in preventing caries might be the increase of pH in dental plaque. During recent years, arginine has increasingly become the focus of interest. This is based on the fact that certain streptococci possess an arginine deiminase system (ADS) which metabolizes free arginine. In vivo, the incidence of caries was inversely correlated with ADS activity in saliva and dental plaque. ADS is highly active in Streptococcus gordonii and S. sanguinis, but is absent in S. sobrinus and S. mutans. In the presence of 1.5% L-arginine, S. gordonii and S. sanguinis, but not S. mutans and S. sobrinus, synthesize the metabolite citrulline and increase the pH of the environment.In defined multispecies biofilms consisting of ADS-positive and ADS-negative streptococci, supplementation with 1.5% arginine suppressed the growth of ADS-negative by favoring ADS-positive streptococci together with an increase in the pH of the environment. Evaluating the influence of daily manual removal of the biofilm in vitro by brushing with a commercial toothpaste containing fluoride and arginine resulted in less surface microhardness even when compared with a toothpaste with fluoride only. Recent studies clinically investigated the effect of using an arginine-containing dentifrice and reported a decrease of DMFS by about 10-20%., (© 2021 S. Karger AG, Basel.)

The goal of modern periodontal therapy, both during the initial stages and during maintenance, is to create biologically acceptable tooth surfaces through sub- and supragingival cleaning, which enables binding of the connective tissue to the greatest extent possible. In past centuries, the focus of periodontal treatment was on the removal of the supposed cause of periodontal disease, the supra- and supragingival calculus and "infected" root cementum. The findings on the importance of biofilm1 (plaque) and the endogenous responses to biofilm metabolism have shifted the therapeutic focus to elimination of the biofilm. The importance of avoiding injury to the hard and soft dental tissue is nowadays of upmost importance. For classical scaling and root planing to remove mineralized deposits and "infected" cementum, only hand instruments were available in the past. The regular, long-term use of these tools is associated with changes in the hard and soft tooth tissues, and with pain and sensitivity experienced by the patient during and after treatment. Modern root-surface debridement primarily uses ultrasound systems to remove hard mineralized deposits. For biofilm management, air polishing devices with low-abrasive powders are increasingly gaining acceptance. With this new technology, biofilm management can now be performed much more effectively and efficiently, using materials more sparingly; this also causes less pain and discomfort for patients during and after treatment, and less fatigue for practitioners. The modern systems allow gentle, optimal biofilm management, whereas the traditional hand instruments (curettes, scalers) and classic rotating instruments used for polishing do not. Current knowledge suggests that these instruments are not best suited for biofilm management., (© 2021 S. Karger AG, Basel.)

The pH value of a biofilm influences the pathogenesis and therapy of oral diseases such as caries and periodontitis. This study aimed to investigate the influence of different initial pH values on the microbial composition, bacterial counts, metabolic activity, and quantity of three defined biofilms representing oral health, caries, and periodontal disease. Respective bacterial suspensions in the nutrient broth were initially adjusted to pH values between 5 and 8. Then biofilms were cultured on polystyrene surfaces coated with a proteinaceous solution for 2 h ("healthy" biofilm), 6 h ("healthy," and "cariogenic" biofilms), 24 h ("cariogenic," and "periodontitis" biofilms), and 48 h ("periodontitis" biofilm). In all biofilms, total bacterial counts were lower at an initial pH of 5 or 5.5 than at higher pH values. In the biofilm representing caries, the percentage of cariogenic bacteria (Streptococcus mutans, S. sobrinus, Lactobacillus acidophilus) was higher at a low pH, the metabolic activity was highest at pH 6-6.5, and biofilm mass was greatest at pH 7-7.5. In the biofilm representing periodontitis, the percentage of Porphyromonas gingivalis increased with the pH. Also, the metabolic activity was highest at pH 8, whereas mass had the highest value at pH 7. In conclusion, the initial pH value influences biofilm formation. In particular, metabolic activity and the amount of bacteria associated with disease correlated with the respective pH known to be of importance in the development of caries (relatively low pH) and periodontitis (higher pH). Modifying the pH level in oral biofilms might be an alternative concept in (primary) prevention and treatment, not only of caries but also of periodontitis., (© 2021 S. Karger AG, Basel.)

The formation of a physiological biofilm cannot be avoided under normal circumstances. However, the consequences of a supragingivally located biofilm, such as caries, gingivitis and, as a further effect, periodontitis, are relatively easy to avoid. The simplest and most common method used worldwide for the elimination of biofilm is periodic mechanical removal using a toothbrush or similar tools, such as chewing sticks or woods. This method was already used in ancient Egypt, and is still being used today, albeit advanced and improved with the help of toothpastes. Here we give a summary of the most common toothbrushes, highlighting their advantages and disadvantages. Furthermore, we provide an overview of the most common toothpastes, their ingredients, and functions. In addition, the ingredients will be critically evaluated and recommendations given for the use or non-use of certain ingredients for different target groups, such as children, healthy adults, or patients with special needs., (© 2021 S. Karger AG, Basel.)

Dental erosion is the partial demineralisation of the tooth surface caused by repeated exposure to acids. The loss of surface tissue, which results from simultaneous and/or subsequent exposure to mechanical forces is known as erosive tooth wear (ETW). Excessive consumption of acidic beverages and foods has been the main focus of research into erosion. Enamel dissolution is significantly associated with chemical parameters: pH, buffer capacity, titratable acidity, viscosity, as well as calcium, phosphate and fluoride concentrations in the beverages and foods. Some of these parameters are used to calculate the degree of saturation of a given substance, which represents its driving force to demineralise dental hard tissues. Undersaturated substances with low pH and high titratable acidity and high buffer capacity have greater erosive potential, while substances with high concentrations of Ca2+ and phosphate cause less demineralisation. Other physical parameters also modulate the demineralisation processes. Swishing drinks in the mouth tends to cause more erosion, since the Nernst layer is continuously renewed and does not reach saturation. Recent systematic reviews confirm that frequent consumption of carbonated/soft drinks are the main dietary factor associated with ETW. Vitamin C and frequent consumption of natural fruit juices and acidic snacks or sweets are also significantly associated with more ETW; whereas higher consumption of milk and yoghurt is a protecting factor. Patients presenting with ETW should have their dietary habits assessed by recording their complete dietary intake in a diet record sheet. Dentists should assess the erosive potential of the different beverages and foods, as well as the frequency of ingestion, then elaborate specific preventive measures and dietary interventions individually tailored to each patient., (© 2020 S. Karger AG, Basel.)

The difference between carious lesion diagnosis and carious lesion detection is discussed here. Concerning carious lesions, 3 diagnostic requirements should be fulfilled: to detect lesions, to assess surface integrity, and to assess lesion activity to support clinical decision making. The first and most important diagnostic method is meticulous visual-tactile inspection. This is the only method that potentially contributes to all 3 diagnostic requirements. All other methods that are presented in this chapter, i.e., bitewing radiography, fluorescence-based technologies, and transillumination methods, are limited to assessing lesion depth in surfaces that are not visible to the eye and thus contribute to lesion detection only. At the end of the chapter, recent developments in objective lesion activity assessment are presented., (© 2018 S. Karger AG, Basel.)

Despite certain similarities in the etiology of root caries (RC) and coronal caries, there are notable differences in their histology, namely with regard to the demineralization process, which should be taken into consideration when assessing lesion activity. In this chapter, we present the histological changes to the dentin and pulp, occurring physiologically or in response to caries lesions. We focus on the histological features specific to RC lesions, discussing the assessment of lesion activity. The physiological changes occurring to the dentin and pulp are the formation of secondary dentin and the sclerosis of dentin tubules, while tertiary dentin is formed during pathologic stimuli from caries lesions. Already in the early stages of active RC, the lesions seem softer, and bacteria are easily found within the dentin tubules. Inactive lesions, on the contrary, are characterized by fully remineralized tissue, with irregular mineral precipitation and containing ghost cells of microorganisms. Lesion activity is determined by observing their tactile sensation and their position with respect to the gingival margin., (© 2017 S. Karger AG, Basel.)

Dental erosion is often described solely as a surface phenomenon, unlike caries where it has been established that the destructive effects involve both the surface and the subsurface region. However, besides removal of the surface, erosion shows dissolution of mineral within the softened layer - beneath the surface. In order to distinguish this process from the carious process it is now called 'near surface demineralization'. Erosion occurs in low pH, but there is no fixed critical pH value concerning dental erosion. The critical pH value for enamel concerning caries (pH 5.5-5.7) has to be calculated from calcium and phosphate concentrations of plaque fluid. In the context of dental erosion, the critical pH value is calculated from the calcium and phosphate concentrations in the erosive solution itself. Thus, critical pH for enamel with regard to erosion will vary according to the erosive solution. Erosive tooth wear is becoming increasingly significant in the management of the long-term health of the dentition. What is considered as an acceptable amount of wear is dependent on the anticipated lifespan of the dentition and is, therefore, different for deciduous compared to permanent teeth. However, erosive damage to the teeth may compromise the patient's dentition for their entire lifetime and may require repeated and increasingly complex and expensive restorations. Therefore, it is important that diagnosis of the tooth wear process in children and adults is made early and that adequate preventive measures are undertaken. These measures can only be initiated when the risk factors are known and interactions between them are present., (© 2014 S. Karger AG, Basel.)

Dental erosion is caused by repeated short episodes of exposure to acids. Dental minerals are calcium-deficient, carbonated hydroxyapatites containing impurity ions such as Na(+), Mg(2+) and Cl(-). The rate of dissolution, which is crucial to the progression of erosion, is influenced by solubility and also by other factors. After outlining principles of solubility and acid dissolution, this chapter describes the factors related to the dental tissues on the one hand and to the erosive solution on the other. The impurities in the dental mineral introduce crystal strain and increase solubility, so dentine mineral is more soluble than enamel mineral and both are more soluble than hydroxyapatite. The considerable differences in structure and porosity between dentine and enamel influence interactions of the tissues with acid solutions, so the relative rates of dissolution do not necessarily reflect the respective solubilities. The rate of dissolution is further influenced strongly by physical factors (temperature, flow rate) and chemical factors (degree of saturation, presence of inhibitors, buffering, pH, fluoride). Temperature and flow rate, as determined by the method of consumption of a product, strongly influence erosion in vivo. The net effect of the solution factors determines the overall erosive potential of different products. Prospects for remineralization of erosive lesions are evaluated., (© 2014 S. Karger AG, Basel.)

A prerequisite for preventive measures is to diagnose erosive tooth wear and to evaluate the different etiological factors in order to identify persons at risk. No diagnostic device is available for the assessment of erosive defects. Thus, they can only be detected clinically. Consequently, erosion not diagnosed at an early stage may render timely preventive measures difficult. In order to assess the risk factors, patients should record their dietary intake for a distinct period of time. Then a dentist can determine the erosive potential of the diet. A table with common beverages and foodstuffs is presented for judging the erosive potential. Particularly, patients with more than 4 dietary acid intakes have a higher risk for erosion when other risk factors are present. Regurgitation of gastric acids is a further important risk factor for the development of erosion which has to be taken into account. Based on these analyses, an individually tailored preventive program may be suggested to the patients. It may comprise dietary advice, use of calcium-enriched beverages, optimization of prophylactic regimes, stimulation of salivary flow rate, use of buffering medicaments and particular motivation for nondestructive toothbrushing habits with an erosive-protecting toothpaste as well as rinsing solutions. Since erosion and abrasion often occur simultaneously, all of the causative components must be taken into consideration when planning preventive strategies but only those important and feasible for an individual should be communicated to the patient., (© 2014 S. Karger AG, Basel.)

Erosive demineralisation causes characteristic histological features. In enamel, mineral is dissolved from the surface, resulting in a roughened structure similar to an etching pattern. If the acid impact continues, the initial surface mineral loss turns into bulk tissue loss and with time a visible defect can develop. The microhardness of the remaining surface is reduced, increasing the susceptibility to physical wear. The histology of eroded dentine is much more complex because the mineral component of the tissue is dissolved by acids whereas the organic part is remaining. At least in experimental erosion, a distinct zone of demineralised organic material develops, the thickness of which depends on the acid impact. This structure is of importance for many aspects, e.g. the progression rate or the interaction with active agents and physical impacts, and needs to be considered when quantifying mineral loss. The histology of experimental erosion is increasingly well understood, but there is lack of knowledge about the histology of in vivo lesions. For enamel erosion, it is reasonable to assume that the principal features may be similar, but the fate of the demineralised dentine matrix in the oral cavity is unclear. As dentine lesions normally appear hard clinically, it can be assumed that it is degraded by the variety of enzymes present in the oral cavity. Erosive tooth wear may lead to the formation of reactionary or reparative dentine., (© 2014 S. Karger AG, Basel.)

When substance loss caused by erosive tooth wear reaches a certain degree, oral rehabilitation becomes necessary. Until some 20 years ago, the severely eroded dentition could only be rehabilitated by the provision of extensive crown and bridge work or removable overdentures. As a result of the improvements in resin composite restorative materials, and in adhesive techniques, it has become possible to rehabilitate eroded dentitions in a less invasive manner. However, even today advanced erosive destruction requires the placement of more extensive restorations such as overlays and crowns. It has to be kept in mind that the etiology of the erosive lesions needs to be determined in order to halt the disease, otherwise the erosive process will continue to destroy tooth substance. This overview presents aspects concerning the restorative materials as well as the treatment options available to rehabilitate patients with erosive tooth wear, from minimally invasive direct composite reconstructions to adhesively retained all-ceramic restorations. Restorative treatment is dependent on individual circumstances and the perceived needs and concerns of the patient. Long-term success is only possible when the cause is eliminated. In all situations, the restorative preparations have to follow the principles of minimally invasive treatment., (© 2014 S. Karger AG, Basel.)

Acidic or EDTA-containing oral hygiene products and acidic medicines have the potential to soften dental hard tissues. The low pH of oral care products increases the chemical stability of some fluoride compounds and favours the incorporation of fluoride ions in the lattice of hydroxyapatite and the precipitation of calcium fluoride on the tooth surface. This layer has some protective effect against an erosive attack. However, when the pH is too low or when no fluoride is present these protecting effects are replaced by direct softening of the tooth surface. Oral dryness can occur as a consequence of medication such as tranquilizers, antihistamines, antiemetics and antiparkinsonian medicaments or of salivary gland dysfunction. Above all, patients should be aware of the potential demineralization effects of oral hygiene products with low pH. Acetyl salicylic acid taken regularly in the form of multiple chewable tablets or in the form of headache powder, as well as chewing hydrochloric acids tablets for the treatment of stomach disorders, can cause erosion. There is most probably no direct association between asthmatic drugs and erosion on the population level. Consumers and health professionals should be aware of the potential of tooth damage not only by oral hygiene products and salivary substitutes but also by chewable and effervescent tablets. Several paediatric medications show a direct erosive potential in vitro. Clinical proof of the occurrence of erosion after use of these medicaments is still lacking. However, regular and prolonged use of these medicaments might bear the risk of causing erosion. Additionally, it can be assumed that patients suffering from xerostomia should be aware of the potential effects of oral hygiene products with low pH and high titratable acidity., (© 2014 S. Karger AG, Basel.)

There is evidence that the presence of erosion is growing steadily. Due to different scoring systems, samples and examiners, it is difficult to compare the different studies. Preschool children from 2 to 5 years showed erosion on deciduous teeth in 1 to 79% of the subjects. Schoolchildren (aged from 5 to 9 years) already had erosive lesions on permanent teeth in 14% of the cases. In the adolescent group (aged between 9 and 20 years), 7 to 100% of the persons examined showed signs of erosion. Incidence data (the increase in the number of subjects presenting signs of dental erosion) was evaluated in four of these studies and presented average annual values between 3.5 and 18%, depending on the initial age of the examined sample. In adults (aged from 18 to 88 years) prevalence data ranged between 4 and 100%. Incidence data are scarce in this age group, and only one study was found analysing the increase of affected surfaces, showing an incidence of 5% for the younger and 18% for older age groups. In general, males present more erosive tooth wear than females. The distribution showed a predominance of affected occlusal surfaces (mandibular first molars) followed by facial surfaces (anterior maxillary teeth). Oral erosion was frequently found on maxillary incisors and canines. Overall, prevalence data are not homogeneous. Nevertheless, there is a trend towards a more pronounced rate of erosion in younger age groups. Furthermore, a tendency was found for more erosive lesions with increasing age and these erosions progressed with age., (© 2014 S. Karger AG, Basel.)

The clinical diagnosis 'erosion' is made from characteristic deviations from the original anatomical tooth morphology, thus distinguishing acid-induced tissue loss from other forms of wear. Primary pathognomonic features are shallow concavities on smooth surfaces occurring coronal from the enamel-cementum junction. Problems from diagnosing occlusal surfaces and exposed dentine are discussed. Indices for recording erosive wear include morphological as well as quantitative criteria. Currently, various indices are used, each having their virtues and flaws, making the comparison of prevalence studies difficult. The Basic Erosive Wear Examination (BEWE) is described, which is intended to provide an easy tool for research as well as for use in general dental practice. The cumulative score of this index is the sum of the most severe scores obtained from all sextants and is linked to suggestions for clinical management. In addition to recording erosive lesions, the assessment of progression is important as the indication of treatment measures depends on erosion activity. A number of evaluated and sensitive methods for in vitro and in situ approaches are available, but the fundamental problem for their clinical use is the lack of reidentifiable reference areas. Tools for clinical monitoring are described., (© 2014 S. Karger AG, Basel.)

Erosive tooth wear in children is a common condition. Besides the anatomical differences between deciduous and permanent teeth, additional histological differences may influence their susceptibility to dissolution. Considering laboratory studies alone, it is not clear whether deciduous teeth are more liable to erosive wear than permanent teeth. However, results from epidemiological studies imply that the primary dentition is less wear resistant than permanent teeth, possibly due to the overlapping of erosion with mechanical forces (like attrition or abrasion). Although low severity of tooth wear in children does not cause a significant impact on their quality of life, early erosive damage to their permanent teeth may compromise their dentition for their entire lifetime and require extensive restorative procedures. Therefore, early diagnosis of erosive wear and adequate preventive measures are important. Knowledge on the aetiological factors of erosive wear is a prerequisite for preventive strategies. Like in adults, extrinsic and intrinsic factors, or a combination of them, are possible reasons for erosive tooth wear in children and adolescents. Several factors directly related to erosive tooth wear in children are presently discussed, such as socio-economic aspects, gastroesophageal reflux or vomiting, and intake of some medicaments, as well as behavioural factors such as unusual eating and drinking habits. Additionally, frequent and excessive consumption of erosive foodstuffs and drinks are of importance., (© 2014 S. Karger AG, Basel.)

When considering the erosive potential of a food or drink, a number of factors must be taken into account. pH is arguably the single most important parameter in determining the rate of erosive tissue dissolution. There is no clear-cut critical pH for erosion as there is for caries. At low pH, it is possible that other factors are sufficiently protective to prevent erosion, but equally erosion can progress in acid of a relatively high pH in the absence of mitigating factors. Calcium and phosphate concentration, in combination with pH, determine the degree of saturation with respect to tooth minerals. Solutions supersaturated with respect to enamel or dentine will not cause them to dissolve, meaning that given sufficient common ion concentrations erosion will not proceed, even if the pH is low. Interestingly, the addition of calcium is more effective than phosphate at reducing erosion in acid solutions. Today, several calcium-enriched soft drinks are on the market, and acidic products with high concentrations of calcium and phosphorus are available (such as yoghurt), which do not soften the dental hard tissues. The greater the buffering capacity of the drink or food, the longer it will take for the saliva to neutralize the acid. A higher buffer capacity of a drink or foodstuff will enhance the processes of dissolution because more release of ions from the tooth mineral is required to render the acid inactive for further demineralization. Temperature is also a significant physical factor; for a given acidic solution, erosion proceeds more rapidly the higher the temperature of that solution. In recent years, a number of interesting potentially erosion-reducing drink and food additives have been investigated., (© 2014 S. Karger AG, Basel.)

Dental erosion develops through chronic exposure to extrinsic/intrinsic acids with a low pH. Enamel erosion is characterized by a centripetal dissolution leaving a small demineralized zone behind. In contrast, erosive demineralization in dentin is more complex as the acid-induced mineral dissolution leads to the exposure of collagenous organic matrix, which hampers ion diffusion and, thus, reduces further progression of the lesion. Topical fluoridation inducing the formation of a protective layer on dental hard tissue, which is composed of CaF(2) (in case of conventional fluorides like amine fluoride or sodium fluoride) or of metal-rich surface precipitates (in case of titanium tetrafluoride or tin-containing fluoride products), appears to be most effective on enamel. In dentin, the preventive effect of fluorides is highly dependent on the presence of the organic matrix. In situ studies have shown a higher protective potential of fluoride in enamel compared to dentin, probably as the organic matrix is affected by enzymatical and chemical degradation as well as by abrasive influences in the clinical situation. There is convincing evidence that fluoride, in general, can strengthen teeth against erosive acid damage, and high-concentration fluoride agents and/or frequent applications are considered potentially effective approaches in preventing dental erosion. The use of tin-containing fluoride products might provide the best approach for effective prevention of dental erosion. Further properly designed in situ or clinical studies are recommended in order to better understand the relative differences in performance of the various fluoride agents and formulations., (Copyright © 2011 S. Karger AG, Basel.)

Lesion detection aids ideally aim at increasing the sensitivity of visual caries detection without trading off too much in terms of specificity. The use of a dental probe (explorer), bitewing radiography and fibre-optic transillumination (FOTI) have long been recommended for this purpose. Today, probing of suspected lesions in the sense of checking the 'stickiness' is regarded as obsolete, since it achieves no gain of sensitivity and might cause irreversible tooth damage. Bitewing radiography helps to detect lesions that are otherwise hidden from visual examination, and it should therefore be applied to a new patient. The diagnostic performance of radiography at approximal and occlusal sites is different, as this relates to the 3-dimensional anatomy of the tooth at these sites. However, treatment decisions have to take more into account than just lesion extension. Bitewing radiography provides additional information for the decision-making process that mainly relies on the visual and clinical findings. FOTI is a quick and inexpensive method which can enhance visual examination of all tooth surfaces. Both radiography and FOTI can improve the sensitivity of caries detection, but require sufficient training and experience to interpret information correctly. Radiography also carries the burden of the risks and legislation associated with using ionizing radiation in a health setting and should be repeated at intervals guided by the individual patient's caries risk. Lesion detection aids can assist in the longitudinal monitoring of the behaviour of initial lesions., (Copyright 2009 S. Karger AG, Basel)

Several non-invasive and novel aids for the detection of (and in some cases monitoring of) caries lesions have been introduced in the field of 'caries diagnostics' over the last 15 years. This chapter focusses on those available to dentists at the time of writing; continuing research is bound to lead to further developments in the coming years. Laser fluorescence is based on measurements of back-scattered fluorescence of a 655-nm light source. It enhances occlusal and (potentially) approximal lesion detection and enables semi-quantitative caries monitoring. Systematic reviews have identified false-positive results as a limitation. Quantitative light-induced fluorescence is another sensitive method to quantitatively detect and measure mineral loss both in enamel and some dentine lesions; again, the trade-offs with lower specificity when compared with clinical visual detection must be considered. Subtraction radiography is based on the principle of digitally superimposing two radiographs with exactly the same projection geometry. This method is applicable for approximal surfaces and occlusal caries involving dentine but is not yet widely available. Electrical caries measurements gather either site-specific or surface-specific information of teeth and tooth structure. Fixed-frequency devices perform best for occlusal dentine caries but the method has also shown promise for lesions in enamel and other tooth surfaces with multi-frequency approaches. All methods require further research and further validation in well-designed clinical trials. In the future, they could have useful applications in clinical practice as part of a personalized, comprehensive caries management system., (Copyright 2009 S. Karger AG, Basel)

There is some evidence that the presence of erosion is growing steadily. Because of different scoring systems, samples and examiners, it is difficult to compare and judge the outcome of the studies. Preschool children aged between 2 and 5 years showed erosion on deciduous teeth in 6-50% of the subjects. Young schoolchildren (aged 5-9) already had erosive lesions on permanent teeth in 14% of the cases. In the adolescent group (aged between 9 and 17) 11-100% of the young people examined showed signs of erosion. Incidence data (= increase of subjects with erosion) evaluated in three of these studies were 12% over 2 years, 18% over 5 years and 27% over 1.5 years. In adults (aged between 18 and 88), prevalence data ranged between 4 and 82%. Incidence data are scarce; only one study was found and this showed an incidence of 5% for the younger and 18% for the older examined group (= increase of tooth surfaces with erosion). Prevalence data indicated that males had somewhat more erosive tooth wear than females. The distribution of erosion showed a predominance of occlusal surfaces (especially mandibular first molars), followed by facial surfaces (anterior maxillary teeth). Oral erosion was frequently found on maxillary incisors and canines. Overall, prevalence data are not homogeneous. Nevertheless, there is already a trend for more pronounced rate of erosion in younger age groups. Therefore, it is important to detect at-risk patients early to initiate adequate preventive measures.

Acidic or EDTA-containing oral hygiene products and acidic medicines have the potential to soften dental hard tissues. The low pH of oral care products increases the chemical stability of some fluoride compounds, favors the incorporation of fluoride ions in the lattice of hydroxyapatite and the precipitation of calcium fluoride on the tooth surface. This layer has some protective effect against an erosive attack. However, when the pH is too low or when no fluoride is present these protecting effects are replaced by direct softening of the tooth surface. Xerostomia or oral dryness can occur as a consequence of medication such as tranquilizers, anti-histamines, anti-emetics and anti-parkinsonian medicaments or of salivary gland dysfunction e.g. due to radiotherapy of the oral cavity and the head and neck region. Above all, these patients should be aware of the potential demineralization effects of oral hygiene products with low pH and high titratable acids. Acetyl salicylic acid taken regularly in the form of multiple chewable tablets or in the form of headache powder as well chewing hydrochloric acids tablets for treatment of stomach disorders can cause erosion. There is most probably no direct association between asthmatic drugs and erosion on the population level. Consumers, patients and health professionals should be aware of the potential of tooth damage not only by oral hygiene products and salivary substitutes but also by chewable and effervescent tablets. Additionally, it can be assumed that patients suffering from xerostomia should be aware of the potential effects of oral hygiene products with low pH and high titratable acids.

Biological factors such as saliva, acquired dental pellicle, tooth structure and positioning in relation to soft tissues and tongue are related to dental erosion development. Saliva has been shown to be the most important biological factor in the prevention of dental erosion. It starts acting even before the acid attack, with the increase of the salivary flow rate as a response to the acidic stimuli. This creates a favorable scenario, increasing the buffering system of saliva and effectively diluting and clearing acids on dental surfaces during the erosive challenge. Saliva plays a role in the formation of the acquired dental pellicle, which acts as a perm-selective membrane preventing contact of the acid with the tooth surfaces. The protective level of the pellicle seems to be regulated by its composition, thickness and maturation time. Due to its mineral content, saliva can also prevent demineralization as well as enhance remineralization. However, these preventive and reparative factors of saliva may not be enough against highly erosive challenges, leading to erosion development. The progress rate of erosion can be significantly influenced by the type of dental substrate, occurrence of mechanical and chemical attacks, fluoride exposure, and also by contact with the oral soft tissues and tongue.

When substance loss caused by erosive tooth wear reaches a certain degree, oral rehabilitation becomes necessary. Prior to the most recent decade, the severely eroded dentition could only be rehabilitated by the provision of extensive crown and bridge work or removable overdentures. As a result of the improvements in composite restorative materials, and in adhesive techniques, it has become possible to rehabilitate eroded dentitions in a less invasive manner. However, even today advanced erosive destruction requires the placement of more extensive restorations such as ceramic veneers or overlays and crowns. It has to be kept in mind that the etiology of the erosive lesions needs to be determined in order to halt the disease, otherwise the erosive process will continue to destroy tooth substance. This overview presents aspects concerning the restorative materials as well as the treatment options available to rehabilitate patients with erosion, from minimally invasive direct composite reconstructions to adhesively retained all-ceramic restorations. Restorative treatment is dependent on individual circumstances and the perceived needs and concerns of the patient. Long-term success is only possible when the cause is eliminated. In all situations, the restorative preparations have to follow the principles of minimally invasive treatment.

A prerequisite for preventive measures is to diagnose erosive tooth wear and to evaluate the different etiological factors in order to identify persons at risk. No diagnostic device is available for the assessment of erosive defects. Thus, they can only be detected clinically. Consequently, erosion not diagnosed in the early stage may render timely preventive measures difficult. In order to assess the risk factors, patient should record their dietary intake for a distinct period of time. Then a dentist can determine the erosive potential of the diet. Particularly, patients with more than four dietary acid intakes have a higher risk for erosion when other risk factors (such as holding the drink in the mouth) are present. Regurgitation of gastric acids (reflux, vomiting, alcohol abuse, etc.) is a further important risk factor for the development of erosion which has to be taken into account. Based on these analyses, an individually tailored preventive program may be suggested to the patients. It may comprise dietary advice, optimization of fluoride regimes, stimulation of salivary flow rate, use of buffering medicaments and particular motivation for nondestructive toothbrushing habits with a low abrasive toothpaste. The frequent use of fluoride gel and fluoride solution in addition to fluoride toothpaste offers the opportunity to reduce somewhat abrasion of tooth substance. It is also advisable to avoid abrasive tooth cleaning and whitening products, since they may remove the pellicle and may render teeth more susceptible to erosion. Since erosion, attrition and abrasion often occur simultaneously all causative components must be taken into consideration when planning preventive strategies.

pH value, calcium, and phosphate and to a lesser extent fluoride content of a drink or foodstuff are important factors explaining erosive attack. They determine the degree of saturation with respect to tooth minerals, which is the driving force for dissolution. Solutions oversaturated with respect to dental hard tissue will not dissolve it. Addition of calcium (and phosphate) salts to erosive drinks showed protection of surface softening. Today, several Ca-enriched soft drinks are on the market or products with naturally high content in Ca and P are available (such as yoghurt), which do not soften the dental hard tissue. The greater the buffering capacity of the drink or food, the longer it will take for the saliva to neutralize the acid. The buffer capacity of a solution has a distinct effect on the erosive attack when the solution remains adjacent to the tooth surface and is not replaced by saliva. A higher buffer capacity of a drink or foodstuff will enhance the processes of dissolution because more ions from the tooth mineral are needed to render the acid inactive for further demineralization. Further, the amount of drink in the mouth in relation to the amount of saliva present will modify the process of dissolution. There is no clear-cut critical pH for erosion as there is for caries. Even at a low pH, it is possible that other factors are strong enough to prevent erosion.

During and after an erosive challenge, behavioral factors play a role in modifying the extent of erosive tooth wear. The manner that dietary acids are introduced into the mouth (gulping, sipping, use of a straw) will affect how long the teeth are in contact with the erosive challenge. The frequency and duration of exposure to an erosive agent is of paramount importance. Night-time exposure (e.g. baby bottle-feeding) to erosive agents may be particularly destructive because of the absence of salivary flow. Health-conscious individuals tend to ingest acidic drinks and juices more frequently and tend to have higher than average oral hygiene. While good oral hygiene is of proven value in the prevention of periodontal disease and dental caries, frequent toothbrushing with abrasive oral hygiene products may enhance erosive tooth wear. Unhealthy lifestyles such as consumption of designer drugs, alcopops and alcohol abuse are other important behavioral factors.

The clinical diagnosis 'erosion' is made from characteristic deviations from the original anatomical tooth morphology, thus, distinguishing acid induced tissue loss from other forms of wear. Primary pathognomonic features are shallow concavities on smooth surfaces occurring coronal from the enamel-cementum junction. Problems from diagnosing occlusal surfaces and exposed dentine are discussed. Indices for recording erosive wear include morphological as well as quantitative criteria. Currently, various indices are used making the comparison of prevalence studies difficult. The most important and frequently used indices are described. In addition to recording erosive lesions, the assessment of progression is important as the indication of treatment measures depends on erosion activity. A number of evaluated and sensitive methods for in vitro and in situ approaches are available, but the fundamental problem for their clinical use is the lack of re-identifiable reference areas. Tools for clinical monitoring are described.

In rare cases the occupation - be it at work or during professional and strenuous sports activities - may give a clue to a patient's risk factors for dental erosion. However, no detrimental effects were described on a population level. Frequent contact to inorganic or organic acids at work could increase the occurrence and progression of erosion. In some studies, acid workers had significantly more teeth with erosive tooth wear than the controls. Clinical findings showed erosion mainly on upper anterior teeth and dentine hypersensitivity. Occupation groups at risk would mostly be found in the chemical industry, but also others like wine tasters may have dental erosion. A few case reports and studies have reported an association between sports activities and erosive tooth wear. The cause could be direct acid exposure or strenuous exercise, which may increase gastroesophageal reflux. Risk groups are swimmers exercising in water with low pH and athletes consuming frequently erosive sport drinks. It has to be kept in mind that sports drinks and occupation can be for some patients a cofactor in the development or in the increase of dental erosion. However, it is unlikely that one or two isolated factors will be responsible for this multifactorial condition.

Dental erosion is often described solely as a surface phenomenon, unlike caries where it has been established that the destructive effects involve both the surface and the subsurface region. However, besides removal and softening of the surface, erosion may show dissolution of mineral underneath the surface. There is some evidence that the presence of this condition is growing steadily. Hence, erosive tooth wear is becoming increasingly significant in the management of the long-term health of the dentition. What is considered as an acceptable amount of wear is dependent on the anticipated lifespan of the dentition and, therefore, is different for deciduous compared to permanent teeth. However, erosive damage to the permanent teeth occurring in childhood may compromise the growing child's dentition for their entire lifetime and may require repeated and increasingly complex and expensive restoration. Therefore, it is important that diagnosis of the tooth wear process in children and adults is made early and adequate preventive measures are undertaken. These measures can only be initiated when the risk factors are known and interactions between them are present. A scheme is proposed which allows the possible risk factors and their relation to each other to be examined.

The mineral in our teeth is composed of a calcium-deficient carbonated hydroxyapatite (Ca10-xNax(PO4)6-y(CO3)z(OH)2-uFu). These substitutions in the mineral crystal lattice, especially carbonate, renders tooth mineral more acid soluble than hydroxyapatite. During erosion by acid and/or chelators, these agents interact with the surface of the mineral crystals, but only after they diffuse through the plaque, the pellicle, and the protein/lipid coating of the individual crystals themselves. The effect of direct attack by the hydrogen ion is to combine with the carbonate and/or phosphate releasing all of the ions from that region of the crystal surface leading to direct surface etching. Acids such as citric acid have a more complex interaction. In water they exist as a mixture of hydrogen ions, acid anions (e.g. citrate) and undissociated acid molecules, with the amounts of each determined by the acid dissociation constant (pKa) and the pH of the solution. Above the effect of the hydrogen ion, the citrate ion can complex with calcium also removing it from the crystal surface and/or from saliva. Values of the strength of acid (pKa) and for the anion-calcium interaction and the mechanisms of interaction with the tooth mineral on the surface and underneath are described in detail.

Erosive tooth wear in children is a common condition. The overlapping of erosion with mechanical forces like attrition or abrasion is probably in deciduous teeth more pronounced than in permanent teeth. Early erosive damage to the permanent teeth may compromise the dentition for the entire lifetime and require extensive restorative procedures. Therefore, early diagnosis of the condition and adequate preventive measures are of importance. Knowledge of the etiological factors for erosive tooth wear is a prerequisite for such measures. In children and adolescents (like in adults) extrinsic and intrinsic factors or a combination of them are possible reasons for the condition. Such factors are frequent and extensive consumption of erosive foodstuffs and drinks, the intake of medicaments (asthma), gastro-esophageal reflux (a case history is discussed) or vomiting. But also behavioral factors like unusual eating and drinking habits, the consumption of designer drugs and socio-economic aspects are of importance.