Erosive tooth wear: diagnosis, risk factors and prevention

PURPOSE: To provide an overview on diagnosis, risk factors and prevention of erosive tooth wear, which is becoming an increasingly important factor when considering the long- term health of the dentition. RESULTS: Awareness of dental erosion by the public is still not widespread due to the cryptic nature of this slowly progressing condition. Smooth silky-glazed appearance with the absence of perikymata and intact enamel along the gingival margin, with cupping and grooving on occlusal surfaces are some typical signs of enamel erosion. In later stages, it is sometimes difficult to distinguish between the influences of erosion, attrition or abrasion during a clinical examination. Biological, behavioral and chemical factors all come into play, which over time, may either wear away the tooth surface, or potentially protect it. In order to assess the risk factors, patient should record their dietary intake for a distinct period of time. Based on these analyses, an individually tailored preventive program may be suggested to patients. It may comprise dietary advice, optimization of fluoride regimes, stimulation of salivary flow rate, use of buffering medicaments and particular motivation for non-destructive tooth brushing habits. The frequent use of fluoride gel and fluoride mouthrinse in addition to fluoride toothpaste offers the opportunity to minimize abrasion of tooth substance.

Dental erosion in children

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.

Prevalence, incidence and distribution of erosion

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.

Fracture in teeth—a diagnostic for inferring bite force and tooth function

Teeth are brittle and highly susceptible to cracking. We propose that observations of such cracking can be used as a diagnostic tool for predicting bite force and inferring tooth function in living and fossil mammals. Laboratory tests on model tooth structures and extracted human teeth in simulated biting identify the principal fracture modes in enamel. Examination of museum specimens reveals the presence of similar fractures in a wide range of vertebrates, suggesting that cracks extended during ingestion or mastication. The use of ‘fracture mechanics’ from materials engineering provides elegant relations for quantifying critical bite forces in terms of characteristic tooth size and enamel thickness. The role of enamel microstructure in determining how cracks initiate and propagate within the enamel (and beyond) is discussed. The picture emerges of teeth as damage-tolerant structures, full of internal weaknesses and defects and yet able to contain the expansion of seemingly precarious cracks and fissures within the enamel shell. How the findings impact on dietary pressures forms an undercurrent of the study.

The Influence of Fallback Foods on Great Ape Tooth Enamel

Lucas and colleagues recently proposed a model based on fracture and deformation concepts to describe how mammalian tooth enamel may be adapted to the mechanical demands of diet (Lucas et al.: Bioessays 30[2008] 374-385). Here we review the applicability of that model by examining existing data on the food mechanical properties and enamel morphology of great apes (Pan, Pongo, and Gorilla). Particular attention is paid to whether the consumption of fallback foods is likely to play a key role in influencing great ape enamel morphology. Our results suggest that this is indeed the case. We also consider the implications of this conclusion on the evolution of the dentition of extinct hominins.

Properties of tooth enamel in great apes

A comparative study has been made of human and great ape molar tooth enamel. Nanoindentation techniques are used to map profiles of elastic modulus and hardness across sections from the enamel–dentin junction to the outer tooth surface. The measured data profiles overlap between species, suggesting a degree of commonality in material properties. Using established deformation and fracture relations, critical loads to produce function-threatening damage in the enamel of each species are calculated for characteristic tooth sizes and enamel thicknesses. The results suggest that differences in load-bearing capacity of molar teeth in primates are less a function of underlying material properties than of morphology.

Diagnosis of erosive tooth wear

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.

Tactile sensibility of single-tooth implants and natural teeth

AIM: The purpose of this randomized split-mouth clinical trial was to determine the active tactile sensibility between single-tooth implants and opposing natural teeth and to compare it with the tactile sensibility of pairs of natural teeth on the contralateral side in the same mouth (intraindividual comparison). MATERIAL AND METHODS: The hypothesis was that the active tactile sensibilities of the implant side and control side are equivalent. Sixty two subjects (n=36 from Bonn, n=26 from Bern) with single-tooth implants (22 anterior and 40 posterior dental implants) were asked to bite on narrow copper foil strips varying in thickness (5-200 microm) and to decide whether or not they were able to identify a foreign body between their teeth. Active tactile sensibility was defined as the 50% threshold of correct answers estimated by means of the Weibull distribution. RESULTS: The results obtained for the interocclusal perception sensibility differed between subjects far more than they differed between natural teeth and implants in the same individual [implant/natural tooth: 16.7+/-11.3 microm (0.6-53.1 microm); natural tooth/natural tooth: 14.3+/-10.6 microm (0.5-68.2 microm)]. The intraindividual differences only amounted to a mean value of 2.4+/-9.4 microm (-15.1 to 27.5 microm). The result of our statistical calculations showed that the active tactile sensibility of single-tooth implants, both in the anterior and posterior region of the mouth, in combination with a natural opposing tooth is similar to that of pairs of opposing natural teeth (double t-test, equivalence margin: +/-8 microm, P<0.001, power >80%). Hence, the implants could be integrated in the stomatognathic control circuit.

Tooth loss over five years

Objectives: To assess the ability to predict tooth loss on the basis of clinical and radiographic parameters. Methods: Clinical and radiographic data from a five year prospective cohort were studied to identify cause of progressive tooth loss in older subjects. Results: 363 subjects with a baseline mean age of 67.1 years (S.D. + 4.7, range : 60-75), and 51.4% women were studied including 59.5% never smokers, and 33.0% current smokers. At baseline the subjects had, on average, 22.4 teeth (S.D. + 6.4). Self-assessed tooth loss risk was identified by 16.0 % of subjects while 34% of subjects lost teeth. Tooth loss due to caries was found in 24.7% (178 teeth), periodontitis in 15.4% (133 teeth), peri-apical lesions 5.9% (32 teeth), combined periodontal/peri-apical in 3.4% (18 teeth), and teeth irrational to treat in 7.5% (58 teeth) of the subjects. 122 of the extracted teeth (34%) should have been possible to save but were extracted. At year five severe caries, periodontitis, peri-apical lesions, periodontal/peri-apical, irrational to treat were found in 6.3%, 7.2%, 2.6%, 4.6%, and 1.2% of subjects, respectively. Signs of osteoporosis increased by 11.2 % (Klemetti index). Linear regression analysis failed to include smoking habits as being explanatory. Explanatory factors were researcher prediction of extraction needs, subject self assessment of risk and change in ostoporosis status (r2 = 0.39, ANOVA, F=22.6, p< 0.001). Conclusions: Caries and periodontitis are primary causes for extraction. Progressive osteoporosis is associated with tooth loss. Radiographs, and subjects self-assessment of risk for tooth loss are robust predictors.

Injuries to permanent teeth. Part 3: Therapy of root fractures

Diagnostic and therapeutic interventions following dental injuries are not part of the routine practice in the dental office. Quite often, these patients are emergency cases who seek treatment after normal office hours. The objective of this and the future papers is to present the current treatment concepts in dental traumatology at the School of Dental Medicine, University of Berne. The fruitful cooperation in the field of dental traumatology between the Department of Oral Surgery and Stomatology, and the Department of Conservative Dentistry (including pediatric dentistry and endodontology), is based on the interdisciplinary approach that has been established four years ago. Following discussion and evaluation of such treated cases, and considering current clinical and experimental studies, the said concepts have been worked out. The present paper describes the therapeutic approach for root fractures.

Chlorhexidine and preservation of sound tooth structure in older adults. A placebo-controlled trial

The Trial to Enhance Elderly Teeth Health (TEETH) was designed to test the impact of regular rinsing with a 0.12% chlorhexidine (CHX) solution on tooth loss, and the causes of tooth loss (caries, periodontal disease and trauma) were also investigated. This paper reports on the effectiveness of a 0.12% CHX solution for controlling caries using a tooth surface (coronal and root) survival analysis. A total of 1,101 low income elders in Seattle (United States) and Vancouver (Canada), aged 60-75 years, were recruited for a double-blind clinical trial and assigned to either a CHX (n = 550) or a placebo (n = 551) mouth rinse. Subjects alternated between daily rinsing for 1 month, followed by weekly rinsing for 5 months. All sound coronal and root surfaces at baseline were followed annually for up to 5 years. At each follow-up examination, those tooth surfaces with caries, restored, or extracted were scored as 'carious'. The hazard ratio associated with CHX for a sound surface to become filled, decayed, or extracted was 0.87 for coronal surfaces (95% confidence interval: 0.71-1.14, p = 0.20) and 0.91 for root surfaces (95% confidence interval: 0.73-1.14, p = 0.41). These findings suggest that regular rinsing with CHX does not have a substantial effect on the preservation of sound tooth structure in older adults.

Guidelines for the management of traumatic dental injuries. II. Avulsion of permanent teeth

Avulsion of permanent teeth is the most serious of all dental injuries. The prognosis depends on the measures taken at the place of accident or the time immediately after the avulsion. Replantation is the treatment of choice, but cannot always be carried out immediately. An appropriate emergency management and treatment plan is important for a good prognosis. Guidelines are useful for delivering the best care possible in an efficient manner. The International Association of Dental Traumatology (IADT) has developed a consensus statement after a review of the dental literature and group discussions. Experienced researchers and clinicians from various specialties were included in the group. In cases in which the data did not appear conclusive, recommendations were based on the consensus opinion of the IADT board members. The guidelines represent the current best evidence based on literature research and professional opinion. In this second article of three, the IADT Guidelines for management of avulsed permanent teeth are presented.