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Background: The recommendation that Tooth Mousse (TM), an anticariogenic remineralizing agent, is effective for controlling dental erosion in professional wine tasters is not evidence-based. The aim of this in vitro study was to determine the effectiveness of TM in reducing erosion of coronal enamel and radicular dentine/cementum simulating a typical wine judging session. Methods: Enamel and dentine/cementum from buccal halves (experimental sample) and palatal halves (control sample) of human maxillary premolar teeth were subjected to 1500 one-minute exposures (cycles) to white wine (pH = 3.5). TM was applied every 20 cycles to the experimental sample, but not to the control sample. Paired t-tests were used to determine whether there were significant differences in erosion depths between the experimental and control samples. Results: Mean erosion depths were significantly shallower in the experimental sample than the control sample for both enamel (34.4 μm versus 49.2 μm, respectively) (p

Background: Opinions vary about the causes of non-carious cervical lesions (NCCLs). They have been attributed to toothbrush abrasion, acid corrosion (commonly termed dental erosion), and abfraction. The purpose of this study was to examine the microwear details of NCCLs in a collection of extracted human teeth using scanning election microscopy (SEM). Methods: Negative replicas of large NCCLs in 24 extracted human teeth were obtained in polyvinylsiloxane impression material (Light Body Imprint TM II, 3M ESPE) and viewed under SEM. Results: All NCCLs extended from the cemento-enamel junction to the root surface and they displayed a variety of wedgeshaped appearances. There was evidence of both abrasion and corrosion in 18 of the 24 teeth (75.0 per cent), abrasion only in one tooth (4.2 per cent) and corrosion only in five teeth (20.8 per cent). Horizontal furrows with smooth edges and minor scratch marks, characteristic of abrasion and corrosion, were noted in 13 teeth (54.2 per cent). Conclusions: Based on microscopic assessment of a sample of extracted teeth, it appears that abrasion and corrosion are common associated aetiological factors in the formation of NCCLs.

Accurate, reproducible three-dimensional (3D) data provide an important contribution to our ability to describe, compare and understand dental morphology but the existing technology is often expensive or has technical limitations. Recently available, inexpensive 3D profilometers interfaced with standard personal computers offer the potential to overcome some of these problems. This technical note describes a system that uses a 3D profilometer and purpose written software to analyse changes in dental morphology resulting from tooth wear. The validity of the derived data was determined by comparing data derived from scans of objects of known dimensions with calculated volumes. These differences were less than 10% from objects that were difficult to scan because of their geometry and were commonly less than 5%. The reproductibility, expressed as intra- and inter-observer coefficients of variation, was less than 1%. The potential applications of systems of this type are outlined.

Background: Erosive tooth wear and dentinal hypersensitivity are common problems affecting professional wine tasters.By using nanoscratch testing, the aim of this in vitro study was to assess enamel softening under conditions simulating10 one-minute episodes of wine erosion. Methods: Ten enamel specimens were bathed in artificial saliva for 2 hours before being eroded for 10 episodes, with each episode comprising one minute of wine erosion followed by one minute of remineralization in artificial saliva.Nanoscratches were placed with a spherical tip (20 lm radius) in a nanoindenter under a load of 100 mN at baseline(stage 1), after a one-erosion episode (stage 2) and after 10-erosion episodes (stage 3). Results: There were significant effects of erosion stages on both scratch depth (p < 0.001) and surface roughness(p < 0.001). Post hoc tests showed significant differences in both scratch depths and surface roughness between stages 1and 3 (p < 0.001), and between stages 2 and 3 (p < 0.01). Conclusions: Enamel softening occurs at an early stage of wine tasting, emphasizing the need to implement early preventive strategies in professional wine tasters. Further research elucidating the fundamental mechanisms involved in early stages of erosion has the potential to lead to development of more effective preventive strategies. Refereed/Peer-reviewed

There are basic principles that should be followed for the prevention and control of dental erosion. They rely on diminishing or eliminating the acid challenge, overcoming any hypersensitivity, healing the remaining damaged tooth surface by remineralization and protecting the tooth from any subsequent acid attack. Opinions vary as to how this should be achieved and the plethora of products that are available, each with their specific formulations and different concentrations, often causes confusion among clinicians. Although examples of specific products will be mentioned in this chapter, the emphasis will be on general methods with reference to generic products in order to guide management. Although this chapter focuses only on professionally applied products and oral health education, they should only form part of an overall preventive program that includes home preventive measures for which the patient is responsible. Each management plan needs to follow a preventive philosophy that is tailor-made for the patient.

Following the invention of the first computed tomography (CT) scanner in the early 1970s, many innovations in three-dimensional (3D) diagnostic imaging technology have occurred, leading to a wide range of applications in craniofacial clinical practice and research. Three-dimensional image analysis provides superior and more detailed information compared with conventional plain two-dimensional (2D) radiography, with the added benefit of 3D printing for preoperative treatment planning and regenerative therapy. Current state-of-the-art multidetector CT (MDCT), also known as medical CT, has an important role in the diagnosis and management of craniofacial injuries and pathology. Three-dimensional cone beam CT (CBCT), pioneered in the 1990s, is gaining increasing popularity in dental and craniofacial clinical practice because of its faster image acquisition at a lower radiation dose, but sound guidelines are needed to ensure its optimal clinical use. Recent innovations in micro-computed tomography (micro-CT) have revolutionized craniofacial biology research by enabling higher resolution scanning of teeth beyond the capabilities of MDCT and CBCT, presenting new prospects for translational clinical research. Even after four decades of refinement, CT technology continues to advance and broaden the horizons of craniofacial clinical practice and phenomics research.

Corono-radicular grooves (CRGs) are developmental anomalies on maxillary incisor teeth that have both anthropological and clinical significance. Their reported prevalence varies from around 2% in modern Caucasoid populations to 18% in Chinese, although methods of classification have differed between studies. The aim of this study was to determine the frequency of occureence and configuration of these grooves in a large sample of Caucasoid extracted permanent maxillary incisors collected in South Australia during the early 1900s (The Ramsey Smith Collection). A total of 1481 permanent maxillary incisors was examined using a dissecting microscope and classified according to tooth type and side. CRGs were scored according to their location, length, and depth. They were observed in 78 teeth (5.3%), with three teeth displaying two grooves. No significant difference in frequency occurred between central (4.7%) and lateral (5.7%) incisors, nor between right and left sides. Most of the CRGs (51.8%) were located in the mid-palatal region of tooth crowns, originating from the cingukum and terminating on the root surface less than 5.0 mm from the cemento-enamel junction (CEJ). All CRGs were less than 1.0 mm in depth. A higher proportion of CRGs was observed on the distal surface of lateral incisors (28.6%) than central incisors (9.4%). The frequency of occurrence of CRGs recorded in this study was higher than that of some previous reports, although the possibility of sampling bias in collections of exracted teeth needs to be taken into account. The relatively high frequency of CRGs on the distal surface of maxillary lateral incisors has important clinical implications, as plaque accumulation and loss of gingival attachment in this region may lead to severe localized periodontal involvement.

A priority research area in minimal intervention dentistry is the characterization of the early stages of dental erosion. The aim of this in vitro study was to assess the effect of short, repetitive erosive challenges to human enamel over 2 min at pH 1.5 and 3.0 under conditions simulating gastric regurgitation.Enamel surfaces were subjected to erosive challenges at pH 1.5 (Group 1, n=10) and pH 3.0 (Group 2, n=9) for periods of 30s (stage 1), 60s (stage 2) and 120 s (stage 3). Quantitative changes were assessed longitudinally by measuring the 3D average surface roughness (Sa) values using 3D confocal microscopy. Qualitative micrographic assessment of surface changes was also conducted by using environmental scanning electron microscopy.Linear mixed model analysis showed significant effects of the pH values (p0.001) and the stages (p0.001) on the observed Sa values. Post hoc tests showed significant increases in the Sa values between baseline and other stages in both groups (p0.01). The mean Sa values also increased significantly from stage 1 to stage 2 in Group 1 (p0.05). Micrographic analysis displayed severely etched enamel rods in Group 1, but only subtle changes in Group 2.The complexity of the enamel surface is influenced by both acid concentration (pH value) and duration of acid exposure during early stages of erosion. Erosion occurring under conditions simulating GORD can be detected in its initial stages, opening up the possibilities of early diagnosis and management of this condition.Erosive tooth wear occurs progressively and insidiously, often creating complex treatment challenges. This emphasizes the need for early diagnosis and management in accordance with minimal intervention philosophy. Our findings provide a foundation for further research that could lead to the development of highly-sensitive clinical diagnostic tools and preventive strategies.

Physiologic changes occur in dental occlusion throughout life, resulting from the interplay between functional demands and reciprocating adaptive responses. These changes have been reported in the anthropological literature and they reflect evolutionary changes in the human stomatognathic system during the Paleolithic, hunter-gatherer period. Specific occlusal changes occur in response to different environments, leading to extensive variation within and between extinct and extant human populations. For example, functional demands can cause occlusal and interproximal tooth wear, resulting in shortening of the dental arch, continual tooth eruption and changes in masticatory patterns. Since the advent of farming through to our current industrialized culture, functional demands on the human masticatory system, and its adaptive responses to these demands, have been reduced considerably. Indeed, it is only occasionally that functional demands are severe enough to lead to obvious pathology in the modern human dentition. In contrast to normal masticatory activity, 'modern-day conditions' such as dental caries, periodontal disease and erosion, can lead to significant changes in dental occlusion that are pathological and need to be treated. The masticatory system is a dynamic, functional unit that displays considerable change over a lifetime. In this concept paper, it is proposed that modern human populations living in industrialized environments display dental occlusions that can be considered to be 'neotenous'; that is, our dentitions tend to reflect an unworn stage of our ancestors that was only seen in infants, juveniles and young adults. Clinicians can draw on both phylogenetic and ontogenetic perspectives of 'functional dental occlusion' to differentiate continual physiological changes occurring over time that require ongoing review, from pathological responses that require intervention.

The continuing studies of the teeth and faces of Australian twins and their families in the Craniofacial Biology Research Group in the School of Dentistry at the University of Adelaide began 30 years ago. Three main cohorts of twins have been recruited, enabling various objectives and specific hypotheses to be addressed about the roles of genetic, epigenetic and environmental influences on human dentofacial growth and development, as well as oral health. This paper highlights some key findings arising from these studies, emphasizing those of direct relevance to practising oral health professionals. We also draw on published literature to review the significant developments in relation to the use of precision 2D and 3D imaging equipment, the application of modern molecular techniques, and the development of sophisticated computer software for analysing genetic relationships and comparing complex shapes. Such developments are valuable for current and future work. Apart from the classical or traditional twin model, there are several other twin models that can be used in research to clarify the relative contributions of genetic, epigenetic and environmental contributions to phenotypic variation. The monozygotic (MZ) co-twin model is one particularly valuable method, given that examination of only one pair of MZ twins can provide considerable insights into underlying causes of observed variation. This model can be used in a dental practice environment, with oral health professionals having the opportunity to explore differences in orofacial structures between MZ co-twins who are attending as patients. As researchers have become more aware of the complexities of the interactions between the genome, the epigenome and the environment during development, there is the need to collect more phenotypic data and define new phenotypes that will better characterize variations in growth processes and health status. When coupled with powerful new genetic approaches, including genome-wide association studies and linkage analyses, exciting opportunities are opening up to unravel the causes of problems in craniofacial growth and common oral diseases in human populations.

The aim of this study was to measure the effect of simulating two different loads on maxillary incisors displaying eight morphological types of non-carious cervical lesions, unrestored and restored with an adhesive restoration, by quantifying the stress distributions generated using finite element analysis.Virtual models of maxillary incisors were generated using the CAD software (RhinoCeros). After composing virtual dental and supporting structures with and without non-carious cervical lesions, each model was meshed using a control mesh device (ANSYS Finite Element Analysis Software). All of the virtual models were subjected to two load types, oblique load and vertical load, to simulate occlusal forces of 100 N each. Comparisons were made between simulated teeth with non-carious cervical lesions, with and without composite resin restorations, and a simulated sound tooth. Data summarizing the stress distributions were obtained in MPa using von Mises criteria.Oblique loading on simulated non-carious cervical lesions resulted in greater stress concentration compared with vertical loading, and non-carious cervical lesions with acute angles displayed higher stress concentrations at the depth of the lesion. Restoring the lesions with an adhesive restoration, such as composite resin, appeared to overcome this stress concentration.Restoring NCCLs with adhesive restorative materials, such as a nanohybrid composite resin, appears to recover the biomechanical behaviour similar to sound teeth.

Sarbin Ranjitkar, John Kaidonis, Colin Hall, Victor Marino, Lindsay Richards and Grant Townsend

Numerous case-control and other studies involving confirmation of gastroesophageal reflux disease (GERD) by esophageal pH-metry and the assessment of dental erosions have shown significant associations between the two conditions in both adults and children. By contrast, when asked to vote on whether GERD may cause dental erosions, only 42% of physicians strongly agreed that such an association existed in adults, and just 12.5% strongly agreed for children, respectively in two global consensus reports. Part of this divergence between the perceptions of physicians and the findings of research publications may reflect a general lack of oral health education during medical training, and cursory oral examinations being made under less-than-ideal conditions. Adequate salivary secretions are essential for the protection of the teeth and the oropharyngeal and esophageal mucosa. The quantity and quality of the saliva require monitoring as many drugs, including several of the proton pump inhibitors (PPIs), can cause hyposalivation. In addition, PPIs do not always result in adequate acid suppression. Therefore, collaboration between physicians and dentists is strongly advocated to prevent or ameliorate possible adverse oral effects from both endogenous and exogenous acids, and to promote adequate saliva production in patients with GERD.

Objective In addition to its role as a remineralizing agent in preventing dental caries, calcium product (CPP–ACP) delivered as a mousse (Tooth Mousse ® , TM) can reduce erosion of enamel and dentine. The aim of this study was to determine whether CPP–ACP could also reduce erosive tooth wear involving toothbrush abrasion. Methods Flat, polished enamel and dentine specimens ( n = 72) were subjected to 10 wear regimes, with each regime involving erosion in 0.3% citric acid (pH 3.2) for 10 min followed by toothbrush abrasion in a slurry of fluoride-free toothpaste and artificial saliva (1:3 ratio by weight) under a load of 2N for 200 cycles. The specimens were immersed in artificial saliva for 2 h between wear regimes. In the experimental group 1, TM (containing CPP–ACP) was applied at the beginning of each wear episode for 5 min whereas TM− (without CPP–ACP) was applied in the experimental group 2. No mousse was applied in the control group. Results TM significantly reduced enamel wear (mean ± S.E., 1.26 ± 0.33 μm in the experimental group 1 vs 3.48 ± 0.43 μm in the control group) and dentine wear (2.16 ± 0.89 μm in the experimental group 1 vs 10.29 ± 1.64 μm in the control group), and dentine wear was significantly less in the experimental group 1 than in the experimental group 2 (5.75 ± 0.98 μm). Conclusion The finding that TM reduced erosive tooth wear involving toothbrush abrasion, probably by remineralizing and lubricating eroded tooth surfaces, may have implications in the management of tooth wear.

We have provided evidence of secular increases in stature and acceleration of skeletal maturation in Australian male children and young adults in recent decades, and relatively less prominent secular increases in stature in females.Our aims were to construct new references for stature and skeletal age in Australians.We conducted a cross-sectional study of 2,497 South Australians, comprising 1,255 males and 1,242 females aged between 9 and 18 years. Clinical records obtained from 1995 to 2005 comprised stature, chronological and skeletal ages of these individuals. Means and standard deviations for stature and skeletal age were visually smoothed for each sex to construct growth charts depicting the 97th, 90th, 75th, 50th, 25th, 10th and 3rd centiles.Comparisons of the new stature references with the NHMRC (1975) charts indicated an upward shift of stature centiles across all age groups in both sexes by around 4-5 cm. Generally, skeletally advanced individuals tended to be taller, and skeletally delayed individuals tended to be shorter compared with the total sample in younger age groups, but this was less apparent in older age groups. Males aged 9 years in our study were skeletally advanced, on average, by 0.4 years, whereas males aged 17 years were skeletally delayed, on average, by 0.3 years compared with the Greulich and Pyle (1959) standards. In contrast, skeletal and chronological ages were concordant in females.Our new references for stature and skeletal age provide up-to-date information for orthodontists, paedodontists and paediatricians requiring growth data for young Australians.

Assessment of growth and maturation in humans has implications in the diagnosis and treatment of growth disorders and in determining timing of orthopaedic interventions.Our aims were to investigate whether there was evidence of recent secular changes in stature and skeletal maturation in Australians, and to report any association between these parameters.The cross-sectional study sample comprised 5,122 South Australian children and young adults, including 2,601 males and 2,521 females aged between 9 and 18 years. Records obtained from 1987 to 2005 included chronological age, stature and skeletal age in these individuals. Centiles for stature were calculated using the National Health and Medical Research Council of Australia (NHMRC) growth references published in 1975. Stature was measured to the nearest 0.1 cm and the developmental stages of strategic ossification centres on hand-wrist radiographs were evaluated using the Greulich and Pyle (1959) atlas method.Average values for stature were consistently greater in the 1995-2005 cohort compared with the 1987-94 cohort for both sexes, although secular increases in females were less prominent compared with males. Males in the 1995-2005 cohort were also skeletally advanced when compared with their counterparts in the 1987-94 cohort, but this trend was not evident in females. There were significant associations between stature and skeletal maturation, with the strongest associations being noted around puberty in both sexes and progressively weaker associations in older age groups.Our findings indicate secular increases in stature in Australian children and young adults of both sexes over the past few decades, and acceleration of skeletal maturation in males.

Background: Pulp stones are discrete calcified bodies found in the dental pulp. The aims of this study were to calculate the prevalence of pulp stones in young Australian adults using radiographs, and to report any associations between occurrence of pulp stones and sex, tooth type, dental arch, side and dental status. Methods: From 217 undergraduate dental students, comprising 123 males and 94 females aged between 17-35 years, 3296 teeth were examined under 2x magnification on bitewing radiographs. Pulp stones were scored as present or absent, and associations with sex, tooth type, dental arch, side and dental status noted. Results: Pulp stones were found in 100 (46.1 per cent) of the subjects and 333 (10.1 per cent) of the teeth examined. Occurrences were rare in premolars (0.4 per cent) but significantly higher in molars (19.7 per cent). Pulp stones were significantly more common in first molars than in second molars, and in maxillary first molars than in mandibular first molars. Carious and/or restored maxillary right first molars and maxillary left second molars displayed higher prevalences of pulp stones than unrestored and intact molars. Conclusion: Pulp stones may provide useful forensic information when examining dental records to identify deceased persons.