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Photobiomodulation (PBM) is reported in many studies to produce dental analgesia without producing thermal damage to tissues. This systematic review aims to assess in vivo studies to support the statement that PBM can produce dental analgesia.A systematic search strategy was constructed, and PubMed, Scopus, and Embase databases were searched. Subsequently, inclusion and exclusion criteria were applied, reference lists were scanned, and hand searched to identify other suitable studies.Five studies met the inclusion criteria. Meta-analysis was not undertaken due to the heterogenous nature of the studies and data. Positive analgesia outcome was obtained in four out of five studies, and one study with no significant results was criticized for poor reporting of laser parameters, small sample size (six).In general, all studies were criticized for poor discussion of all covariates that could have modified the results, consequently resulting in poor quality of evidence, moderate risk of bias, and poor internal validity, as well as external validity. The systematic review also discussed the potential implications of all variables to be considered for future trials, including pulsing mode, contact modes, and tooth characteristics.

Objectives Carabelli is a nonmetric dental trait variably expressed as a small pit to a prominent cusp in the maxillary molars of modern humans. Investigations on the occurrence and expression rates of this trait have been conducted extensively, tracing its origin to genetic sources. However, there remains a lack of understanding about its potential role in chewing. In this study, we examine molar macrowear with the aim of reconstructing Carabelli trait occlusal dynamics occurring during chewing. Methods We have examined 96 deciduous and permanent maxillary molars of children and young adults from Yuendumu, an Australian Aboriginal population that was at an early stage of transition from a nomadic and hunter-gatherer way of life to a more settled existence. We apply a well-established method, called Occlusal Fingerprint Analysis, which is a digital approach for analyzing dental macrowear allowing the reconstruction of jaw movements required to produce wear pattern specific to each tooth. Results Carabelli trait slightly enlarges the surface functional area, especially in those molars where this feature is expressed in its cuspal form and it is closer to the occlusal plane. Moreover, the highly steep contact planes would also indicate that Carabelli wear areas contribute to increasing the shearing abilities of the occluded teeth, which are particularly important when processing fibrous and tough foods. Conclusions The macrowear analysis suggests that Carabelli trait in the Aboriginal people from Yuendumu slightly enhanced occlusion and probably played some functional role during mastication. Future biomechanical and microwear analyses could provide additional information on the mechanical adaptation of Carabelli trait in modern human dentition.

EFNB1 mutation causes craniofrontonasal dysplasia (CFND), a congenital syndrome associated with craniomaxillofacial anomalies characterised by coronal craniosynostosis, orbital hypertelorism, and midface dysplasia. The aim of this murine study was to investigate the effect of the EfnB1 conditional gene deletion in osteoprogenitor cells on the craniomaxillofacial skeletal morphology.The skulls of male and female mice, in which EfnB1 was deleted by Cre (a site-specific DNA recombinase) under the control of the Osterix (Osx) promoter (EfnB1EfnB1Craniofacial phenotype of the murine model of EfnB1 deletion in osteoprogenitor cells partially represents the human CFND phenotype, with implications for better understanding mechanisms involved in skeletal morphogenesis and malocclusion.

X-ray micro-computed tomography (micro-CT) imaging has important applications in microarchitecture analysis of cortical and trabecular bone structure. While standardized protocols exist for micro-CT-based microarchitecture assessment of long bones, specific protocols need to be developed for different types of skull bones taking into account differences in embryogenesis, organization, development, and growth compared to the rest of the body. This chapter describes the general principles of bone microarchitecture analysis of murine craniofacial skeleton to accommodate for morphological variations in different regions of interest.

Craniofacial phenomics has opened up numerous opportunities to correlate genetic and epigenetic factors to craniofacial phenotypes in order to improve our understanding of growth and development in health and disease. Three-dimensional (3D) imaging has played a key role in advancing craniofacial phenomics by facilitating highly sensitive and specific characterizations of craniofacial and dental morphology. Here we describe the use of micro-computed tomography (micro-CT) to image the murine craniofacial complex, followed by surface reconstruction for traditional morphometric analyses. We also describe the application of geometric morphometrics, based on Generalized Procrustes Analysis, for use in human premolars. These principles are interchangeable between various vertebrate species, and between various surface imaging techniques (including micro-CT and 3D surface scanners), offering a high level of versatility and precision for extensive phenotyping of the entire craniofacial complex.

Fluoride has a major role in strengthening the structure of enamel against acids. Despite differences between caries and root resorption processes, both events inherently involve acidic dissolution of dental tissues. The aim of the present study was to investigate the effects of water fluoridation levels on the surface roughness of root cementum and resorption craters. The findings provided more insight into the influence of fluoride on the surfaces of intact cementum surface and resorption craters.Twenty-eight orthodontic patients were recruited from two cities in Turkey, with high (≥ 2 ppm) and low (≤ 0.05 ppm) water fluoridation. These patients needed bilateral maxillary first premolar extraction as part of their orthodontic treatment and were allocated into two study groups (n = 14 in each group) based on water fluoridation exposure level: the high-fluoride group (HF) and low-fluoride group (LF). 150 g of buccal tipping forces was applied to all maxillary first premolar teeth for 12 weeks with a beta-titanium spring which was reactivated every 4 weeks. All maxillary premolars were removed at the end of the experiment for surface roughness assessment using three-dimensional confocal microscopy and the associated software. The buccal root surface and the largest buccal resorption crater were investigated.Resorption craters were significantly rougher in LF group compared to HF group (p = 0.002). Craters were rougher than the intact root surfaces (p = 0.000). Cervical and apical regions were significantly rougher than the middle region (p = 0.000 and p = 0.024, respectively).Higher water fluoridation level of ≥ 2 ppm resulted in significantly smoother root resorption craters than low water fluoridation level of ≤ 0.05 ppm when the teeth were subjected to 150 g of buccal tipping force. Fluoride seems to have a protective role at the interface of root resorption, and further mineral or histological studies may shed light on the exact protective process against root resorption.

Nasorespiratory obstruction has been purported to influence dentofacial growth adversely. This has sparked considerable debate for decades with a resurgence in interest in 'airway friendly orthodontics' among both general and specialist dental practitioners. This critical review aims to evaluate the current literature relating to two questions: does nasorespiratory obstruction alter dentofacial growth, and does early intervention targeted at alleviating nasorespiratory obstruction improve dentofacial growth? The strength of association between nasorespiratory obstruction, mouth breathing and a long face is weak. The common methodological flaws in research include unblinded and cross-sectional study designs, a lack of adequate controls, inadequate follow-up, subjective assessments and inadequate statistical power. Vertical dentofacial growth has a strong genetic influence, which implies a relatively minor contribution of environmental factors including airway obstruction. The current evidence does not support recommending procedures, such as adenotonsillectomy and maxillary expansion, with the singular aim of negating a hyperdivergent (vertical) dentofacial growth pattern. In light of low-quality evidence, both the World Health Organization guidelines and ethical principles dictate that greater emphasis is placed on avoiding harm and wastage of resources over alternative options. These findings call for quality improvement in undergraduate and postgraduate curricula and continuing professional development for health professionals.

Background: Craniosynostosis is a developmental disorder characterized by the premature fusion of skull sutures, necessitating repetitive, high-risk neurosurgical interventions throughout infancy. This study used protein-releasing Titania nanotubular implant (TNT/Ti) loaded with glypican 3 (GPC3) in the cranial critical-sized defects (CSDs) in Crouzon murine model (Fgfr2c342y/+ knock-in mutation) to address a key challenge of delaying post-operative bone regeneration in craniosynostosis. Materials and methods: A 3 mm wide circular CSD was created in two murine models of Crouzon syndrome: (i) surgical control (CSDs without TNT/Ti or any protein, n=6) and (ii) experimental groups with TNT/Ti loaded with GPC3, further subdivided into the presence or absence of chitosan coating (on nanotubes) (n=12 in each group). The bone volume percentage in CSDs was assessed 90 days post-implantation using micro-computed tomography (micro-CT) and histological analysis. Results: Nano-implants retrieved after 90 days post-operatively depicted well-adhered, hexagonally arranged, and densely packed nanotubes with average diameter of 120±10 nm. The nanotubular architecture was generally well-preserved. Compared with the control bone volume percentage data (without GPC3), GPC3-loaded TNT/Ti without chitosan coating displayed a significantly lower volume percent in cranial CSDs (P

Dentine dysplasia type 1 is a rare and complex dental anomaly. Our aim was to conduct a morphometric assessment of a dentinal dysplasia type 1c (DD1c) caries-free mandibular second molar, extracted due to symptomatic apical periodontitis. Controls consisted of five intact mandibular second molars. Micro-computed tomography analysis showed that the DD1c volume % for enamel, dentine/cementum and pulp chamber fell in the 0.36th, 99.97th and 0.09th percentiles of the control teeth (P < 0.01). It also revealed an extremely complicated root canal system in the DD1c tooth with a varying degree of dentine mineralisation and aberrant dentine deposition in the pulp chamber. A crack extending from the external tooth surface to the pulp chamber was identified as a potential site for microbial invasion. Clinical implications include preventive measures and early intervention in reversible pulpitis. Conclusion: Micro-CT imaging can be useful in establishing post-extraction diagnosis of cracks and phenomic characterisation of tooth anomalies.

The objective of this study was to revisit the topic of compensatory interactions between maxillary anterior teeth during development advanced by Sofaer et al. (1971). We addressed the hypotheses listed by Sofaer and colleagues using data derived from our Australian twin sample to investigate whether final tooth size in permanent maxillary central incisors and canines showed evidence of developmental compensation for adjacent missing or microdont lateral incisors. Such compensation is one factor interacting in the complex system of dental development.A 2D image analysis system was used to measure crown height from the labial view, labiopalatal crown width from the incisal view, and mesiodistal crown width from both the labial (MDl) and incisal (MDi) views of the permanent maxillary central incisors and canines on the dental study model of twins enrolled in a longitudinal study of dental development.Developmental variations of maxillary lateral incisors influence the morphogenesis of the adjacent teeth. For example, individuals with one missing lateral incisor and one lateral incisor of average dimensions, had significantly larger central incisors than the control group for the MDl and MDi dimensions (p 0.05). Of the 7 monozygotic twin pairs, 6 were discordant in maxillary anterior hypodontia and microdontia, and 13 out of 14 dizygotic twin pairs were discordant.This study provides further evidence of developmental interactions in the maxillary anterior region, partially supporting Sofaer and colleagues' hypotheses. These interactions are part of a complex adaptive system involving genetic, epigenetic and environmental factors.

Aim or Purpose: The increasing prevalence of erosive tooth wear among children and young adults is an issue of growing concern, emphasising the need for improvement in the currently used preventive strategies. Our aim was to evaluate individual and synergistic effects of SnF2 and CPP-ACP pastes in inhibiting erosion at a nano-scale. Materials and Methods: Forty flat, polished enamel specimens were subjected to 10 erosion cycles, with each cycle comprising one-min erosion in citric acid (pH 3.0) and one-min exposure to human saliva. In each of the 3 experimental groups (n = 10 per group), a remineralising paste (10% CPP-ACP or 0.45% SnF2 (1,100 ppm F) or SnF2/CPP-ACP (combined 10% CPP-ACP and 0.45% SnF2)) was applied as a slurry in saliva between erosion cycles. No remineralising agent was used in control specimens (n = 10). Erosion was assessed by calculating erosion depth using a novel photolithographic technique combined with high-resolution 3D laser scanning microscopy from baseline to 1 min, 5 min and 10 min. Results: A significant increase in erosion depth was detected in the control group as early as 1 min (69.4 nm) (P < 0.001), with the erosion depths being smaller for all three remineralising agents after 1 min (P ≤ 0.004). The overall trend of erosion depth reduction was SnF2/CPP-ACP > SnF2 > CPP-ACP > control. Conclusions: Application of SnF2-enriched CPP-ACP agent reduces dental erosion more than either SnF2 or CPP-ACP alone, offering a potentially more-effective preventive strategy to manage this condition.

The analysis of dental wear, at both the microscopic and macroscopic scale, is one of the most widely used tools in archeology and anthropology to reconstruct the diet and lifestyle of past human populations. Biomechanical studies have indicated that tooth wear helps to dissipate the mechanical load over the crown surface, thus reducing the risk of tooth fracture. To date, there are only a few studies that have examined functional tooth wear variation in modern humans. Here we propose to study masticatory efficiency through the use of the Occlusal Fingerprint Analysis method, a well-developed digital approach that allows the reconstruction of the occlusal dynamics occurring during mastication. The aim of this study is to provide the first longitudinal quantitative data of molar and premolar macrowear patterns within a functional context. We examined the mixed and permanent dentition of one Australian Aboriginal child (from ages 8 to 17) from Yuendumu, using high-resolution surface scans of dental casts including both upper and lower arches. Our results suggest that the occlusal macrowear patterns of this individual did not significantly change through time. Occlusal contact parameters such as functional area, inclination and direction remain relatively unaltered throughout childhood and adolescence, indicating little change in the masticatory function of this individual. The functional tooth wear pattern in this individual did not change longitudinally indicating the degree of masticatory efficiency has most probably remained unaltered.

This study aimed to investigate size and shape variation of human premolars between Indigenous Australians and Australians of European ancestry, and to assess whether sex and ancestry could be differentiated between these groups using 3D geometric morphometrics.Seventy dental casts from each group, equally subdivided by sex, were scanned using a structured-light scanner. The 3D meshes of upper and lower premolars were processed using geometric morphometric methods. Seventy-two landmarks were recorded for upper premolars and 50 landmarks for lower premolars. For each tooth type, two-way ANOVA was used to assess group differences in centroid size. Shape variations were explored using principal component analysis and visualized using 3D morphing. Two-way Procrustes ANOVA was applied to test group differences for ancestry and sex, and a "leave-one-out" discriminant function was applied to assess group assignment.Centroid size and shape did not display significant difference between the sexes. Centroid size was larger in Indigenous Australians for upper premolars and lower second premolars compared to the Australians of European ancestry. Significant shape variation was noted between the two ancestral groups for upper premolars and the lower first premolar. Correct group assignment of individual teeth to their ancestral groups ranged between 80.0 and 92.8% for upper premolars and 60.0 and 75.7% for lower premolars.Our findings provide evidence of significant size and shape variation in human premolars between the two ancestral groups. High classification rates based on shape analysis of upper premolars highlight potential application of geometric morphometrics in anthropological, bioarcheological and forensic contexts.

Objectives Fibroblast growth factor receptor 2 (FGFR2) C342Y/+ mutation is a known cause of Crouzon syndrome that is characterised by craniosynostosis and midfacial hypoplasia. Our aim was to conduct extensive phenotyping of the maxillary, mandibular and dental morphology associated with this mutation. Materials and methods Morphometric data were obtained from 40 mice, representing two genotypes (Crouzon and wild-type) and two sexes (males and females) (n = 10 in each group). Dental analysis further categorised the first molars into the two jaws (maxillary and mandibular) (n = 20 in each group). Maxillary, mandibular and dental morphology was compared by analysing 23 linear landmark-based dimensions in three-dimensional micro-computed tomography reconstructions. Results Compared with wild-type, Crouzon (FGFR2C342Y/+) maxillae were significantly shorter in maximum height, anterior and posterior lengths and middle width, but larger in posterior width (p Conclusions Our findings of hypoplasia in all three planes in Crouzon maxillae and mandibles, together with the presence of bifid mandibular condyles and expansive bone lesions, may be relevant to maxillofacial surgery and orthodontics. Beyond skeletal effects, the FGFR2C342Y/+ mutation is now implicated in affecting tooth development. This study’s skeletal phenomics data also provides baseline data against which the effect of various treatments can now be assessed.

The development of the dentition is a good model of general development; it has the general characteristics of a complex adaptive system. The developmental variation of hypodontia presents with a reduced number of teeth with several other phenotypic changes. The teeth formed are smaller in size, have different crown and root morphology and are delayed in development. The present study is a component of a multi-centre and multidisciplinary collaborative study to investigate hypodontia from genotype to phenotype. This study uses enhanced 3D-imaging techniques in order to increase the range of parameters of the phenotypic outcome: tooth size and tooth shape. The sample consists of orthodontic patients, 60 with hypodontia (30 males and 30 females), and 60 controls matched for age, sex and ethnicity. The material studied for these measurements are the dental models of each patient; these have been imaged with an Amann Girrbach Ceramill Map400 3D scanner. The 3D images produced were all taken by one operator and viewed on MeshLab. The accuracy of the measurements taken was determined through repeat measurements of the same images, undertaken to determine intra and inter-operator reproducibility. This new system was validated by repeating these measurements using the standard 2D caliper technique. Ten repeat measurements were taken on ten models of the lower and upper premolar inter-cuspal distances. The average intra-operator reproducibility for the inter-cuspal distances when measuring the distance between the buccal and palatal cusp of the maxillary premolar was 0.20 mm; the mandibular premolar was 0.32 mm. The results for inter-operator reproducibility demonstrate an average difference of 0.24 mm for the maxillary premolar and 0.16 mm for the lower premolar. This novel method provides an increased range of measurements with good levels of accuracy. This study will go on to establish the variations on the 3D images between the hypodontia and the control group.

Development of the human facial structures including the jaws and dentition occurs in a process that has the characteristics of a complex adaptive system (CAS) influenced by epigenetic, genetic and environmental factors. Earlier studies have suggested dental arch development to be reduced in size in subjects with hypodontia when compared with controls. Hypodontia is a variation of development and presents with a reduced number of teeth together with several other phenotypic changes. This study uses enhanced 3D imaging techniques to increase the accuracy of the measurements of dental arches. The sample consists of orthodontic patients, 60 with hypodontia (thirty males and thirty females), and 60 controls matched for age, gender and ethnicity. One operator using an Amann Girrbach Ceramill Map400 3D scanner recorded the 3D images from dental models. The 3D images were then viewed on MeshLab and the accuracy of the measurements were determined through repeat measurement of the same images; this was undertaken with intra- and inter-operator reproducibility. Ten repeat measurements were taken on 10 different models. Validation of the new system was undertaken by repeating the measurements using the standard 2D caliper technique. Arch dimension measurements were determined from distance between the left-hand side first molar to the right-hand side first molar. Similar measurements were also made for the inter-canine width. The results for average intra-operator measurements were 0.33 mm for the maxillary arch and 0.40 mm for the mandibular arch. The difference in average inter-operator reproducibility was also measured for inter-molar arch dimensions at 0.31 and 0.23 mm for maxillary and mandibular arches, respectively. This novel method provides an increased range of measurement of similar accuracy to standard techniques. This study will proceed to establish the variations on the 3D images between the hypodontia subjects and the control group.

BACKGROUND Information on fracture biomechanics has implications in materials research and clinical practice. The aim of this study was to analyse the influence of non-carious cervical lesion (NCCL) size, restorative status and direction of occlusal loading on the biomechanical behaviour of mandibular premolars, using finite element analysis (FEA), strain gauge tests and fracture resistance tests. METHODS Ten buccal cusps were loaded on the outer and inner slopes to calculate the strain generated cervically. Data were collected for healthy teeth at baseline and progressively at three lesion depths (0.5 mm, 1.0 mm and 1.5 mm), followed by restoration with resin composite. The magnitude and distribution of von Mises stress and maximum principal stress were simulated at all stages using FEA, and fracture strength was also determined (n = 7 per group). RESULTS There were significant effects of the lesion size and loading directions on stress, strain and fracture resistance (p < 0.05). Fracture resistance values decreased with increase in lesion size, but returned to baseline with restorations. CONCLUSIONS Combined assessment of computer-based and experimental techniques provide an holistic approach to characterize the biomechanical behaviour of teeth with both unrestored and restored NCCLs.

Saethre-Chotzen Syndrome (SCS) is an autosomal dominant syndrome that occurs due to a mutation or deletion of the Twist1 gene at chromosome 7p21. Our aim was to conduct a morphometric analysis of the craniofacial features in the mouse associated with a Twist1Micro-computed imaging was conducted for the skulls of forty skeletally mature mice, equally distributed by sex (male and female) and two genotypes (Twist1Compared with wild-type, the murine model of SCS showed these trends: (1) maxillary-zygomatico-temporal region, significantly shorter length and width posteriorly (p0.05), (2) mandible, significantly reduced height and width (p0.05), and (3) teeth, significantly shorter height, shorter mesio-distal width but longer bucco-lingual width (p0.05). In the murine model of SCS, the key morphological variations included incomplete ossification of the temporal bone and zygomatic arch, twisting and/or incomplete ossification of the palatal process of the maxilla, premaxilla and the ventral nasal concha, as well as bifid coronoid processes.The skeletal and dental alterations in the height, length and width provide a foundation for large-scale phenomics studies, which will improve existing knowledge of the Twist1 signalling cascade. This is relevant given the predicted shift towards minimally invasive molecular medical treatment for craniosynostosis.

Shape analysis is important in anthropology, bioarchaeology and forensic science for interpreting useful information from human remains. In particular, teeth are morphologically stable and hence well-suited for shape analysis. In this work, we propose a framework for tooth morphometry using quasi-conformal theory. Landmark-matching Teichmuller maps are used for establishing a 1-1 correspondence between tooth surfaces with prescribed anatomical landmarks. Then, a quasi-conformal statistical shape analysis model based on the Teichmuller mapping results is proposed for building a tooth classification scheme. We deploy our framework on a dataset of human premolars to analyze the tooth shape variation among genders and ancestries. Experimental results show that our method achieves much higher classification accuracy with respect to both gender and ancestry when compared to the existing methods. Furthermore, our model reveals the underlying tooth shape difference between different genders and ancestries in terms of the local geometric distortion and curvatures. In particular, our experiment suggests that the shape difference between genders is mostly captured by the conformal distortion but not the curvatures, while that between ancestries is captured by both of them.

Chronic orofacial pain of neuropathic origin can present diagnostic and management dilemmas to dental practitioners and also affect the patient's quality of life. Intracranial aneurysms are a potential cause of stroke, with associated sub‐arachnoid haemorrhage leading to high rates of mortality and morbidity. A patient who had been previously managed for symptoms of temporomandibular joint disorder (TMD) presented with sharp, shooting pain of moderate intensity. It was precipitated by swallowing, and radiated to the right throat, posterior border of the mandible, ear and temporomandibular joint. Clinical and radiological investigations excluded odontogenic pain, TMD and other more common causes of facial pain. Magnetic resonance imaging revealed a 7 mm × 6 mm aneurysm in the right middle cerebral artery which was subsequently surgically clipped. Interestingly the facial pain resolved after this procedure. Compression of the insular region of the brain innervated by the trigeminal, glossopharyngeal and vagus nerves provides a plausible explanation for the pain. This is the first case of facial neuralgia associated with an aneurysm in the middle cerebral artery as far as we are aware, and it emphasizes the importance of a multidisciplinary approach in the diagnosis and management of unusual cases of chronic orofacial pain. Refereed/Peer-reviewed

Oral development is a complex adaptive system influenced by genetic, epigenetic and environmental factors. The dental arch develops from 6 weeks in utero until adult life, forming an accessible record to study general growth and development. Increased tooth size in female dizygotic opposite-sex (DZOS) twins compared with female dizygotic same-sex (DZSS) twins provides evidence for the masculinisation of females gestated with a male co-twin, possibly due to the intrauterine influence of male sex hormones: the “Twin Testosterone Transfer” (TTT) hypothesis. This study aimed to investigate the potential influence of intrauterine male hor mones on dental arch size of female DZOS twins. Serial dental models of the primary and permanent dentitions of 69 female DZOS and DZSS twins were examined. Intercanine width, intermolar width, arch length and arch circumference were measured using a customised 2D image analysis system. Unpaired t-tests showed signifi cant differences for mandibular intercanine width (p = 0.03; effect size = 0.6) and borderline differences for mandibular intermolar width and arch circumference (p = 0.05; effect size = 0.5). No significant differences were found in the permanent dentition. These findings provide support for the TTT hypothesis with some arch dimensions being larger in female DZOS twins. We have developed a model of assessing the effects of intrauterine male hormones on the epigenetic changes that last into postnatal life. Our evidence suggests that this is a moderate effect possibly interacting with numerous other environmental factors that may influence arch size.

Background: Current radiography techniques have limitations in detecting subtle odontogenic anomalies or defects that can lead to dentoalveolar and facial infections. This report examines the application of micro-CT imaging on two extracted teeth to enable detailed visualization of subtle odontogenic defects that had given rise to facial swellings. Methods: Two extracted non-carious mandibular left primary canine teeth (73) associated with odontogenic infections were selected from healthy patients, and an intact contralateral tooth (83) from one of the patients was used as a control. All three teeth were subjected to the three-dimensional micro-CT imaging at a resolution of 20 μm. Results: Tooth 73 from the first case displayed dentine pores (channels) that established communication between the pulp chamber and the exposed dentine surface. In comparison, tooth 73 from the second case had a major longitudinal crack extending from the external enamel surface into the pulp chamber. The control tooth did not display any anomalies or major cracks. Conclusions: The scope of micro-CT imaging can be extended from current in vitro applications to establish post-extraction diagnosis of subtle odontogenic defects, in a manner similar to confirming histopathological diagnoses in extracted teeth. Ongoing technological advancements hold the promise for more widespread translatory applications. Refereed/Peer-reviewed

Scale-sensitive fractal analysis of high-resolution 3-dimensional surface reconstructions of wear patterns has advanced our knowledge in evolutionary biology, and has opened up opportunities for translatory applications in clinical practice. To elucidate the microwear characteristics of attrition and erosion in worn natural teeth, we scanned 50 extracted human teeth using a confocal profiler at a high optical resolution (X–Y, 0.17 µm; Z < 3 nm). Our hypothesis was that microwear complexity would be greater in erosion and that anisotropy would be greater in attrition. The teeth were divided into 4 groups, including 2 wear types (attrition and erosion) and 2 locations (anterior and posterior teeth; n = 12 for each anterior group, n = 13 for each posterior group) for 2 tissue types (enamel and dentine). The raw 3-dimensional data cloud was subjected to a newly developed rigorous standardization technique to reduce interscanner variability as well as to filter anomalous scanning data. Linear mixed effects (regression) analyses conducted separately for the dependent variables, complexity and anisotropy, showed the following effects of the independent variables: significant interactions between wear type and tissue type ( P = 0.0157 and P = 0.0003, respectively) and significant effects of location ( P < 0.0001 and P = 0.0035, respectively). There were significant associations between complexity and anisotropy when the dependent variable was either complexity ( P = 0.0003) or anisotropy ( P = 0.0014). Our findings of greater complexity in erosion and greater anisotropy in attrition confirm our hypothesis. The greatest geometric means were noted in dentine erosion for complexity and dentine attrition for anisotropy. Dentine also exhibited microwear characteristics that were more consistent with wear types than enamel. Overall, our findings could complement macrowear assessment in dental clinical practice and research and could assist in the early detection and management of pathologic tooth wear.

The field of dental phenomics provides many opportunities to elucidate the roles of genetic, epigenetic and environmental factors in craniofacial development. To date, research findings have helped to clarify the pathogenesis of many conditions, aiding diagnosis and clinical management. This paper provides an overview of dental phenomics research in some commonly encountered oral diseases in everyday clinical practice, as well as research relating to craniofacial growth and development. Clinically, advances in cariology and periodontology have led to better diagnostic capabilities and treatment provision. In the study of growth and development, important information regarding the varying clinical presentation and pathogenesis of many disorders is now apparent through the accurate quantification of phenotypes. Improvements in two-dimensional (2D) and three-dimensional (3D) imaging and analytical techniques have allowed for accurate dental phenotyping, and efforts are ongoing to apply these in vitro techniques to the in vivo setting. The field of dental phenomics represents an exciting avenue that links research findings to practical application, and collaboration between researcher and clinicians will help advance the field further.

Advances in molecular biology and nanomedicine based therapies hold promise to obviate the need of multiple surgical interventions (associated with current management) in craniosynostosis by preventing bone re-ossification. One such adjunctive therapy involves application of glypicans 1 and 3 (GPC1 and GPC3) that are BMP inhibitors implicated in downregulating the BMP2 activity in prematurely fusing sutures. Electrochemically anodized Titania nanotube (TNT) arrays have been recognized as a promising localized, long-term drug delivery platform for bone-related therapies. This study presents the application of nanoengineered TNT/Ti implants loaded with recombinant glypicans for craniosynostosis therapy. By using Dual luciferase Reporter assay, we tested the biofunctionality of eluted glypicans from the TNT/Ti implants for BMP2 bioactivity regulation in C2C12 murine myoblast cell line. BMP2 activity was inhibited significantly for up to 15days by the glypicans released from polymer-coated TNT/Ti implants, indicating their potential application in adjunctive craniosynostosis treatment.

Titania nanotubes (TNTs) engineered on titanium (Ti) surfaces (i.e. TNT/Ti) and loaded with specific drugs have been recognised as a promising solution for localised therapeutic delivery to address several medical problems not feasible with conventional drug administration. We propose the use of TNT/Ti protein-releasing implants to treat paediatric craniofacial abnormality in craniosynostosis caused by premature fusion of cranial sutures. In this study, we have analysed the biological response of human suture mesenchymal cells (SMCs), extracted from two different patients undergoing craniofacial reconstruction surgery, at the TNT/Ti implant surface. The experimental groups included large-diameter TNT/Ti implants, with and without biopolymer surface coating (Chitosan and Pluronic-F127) while the controls comprised of flat Ti disc and tissue culture plastic. The non-loaded implant surfaces and the cellular interactions at the implant-cell interface were characterised using scanning electron microscopy (SEM). The SMC adhesion, viability and proliferation were determined by MTT assay and manual cell counting at day 1 and day 3 of cell incubation. SEM showed significant reduction in initial attachment and adhesion of SMCs at TNT-cell biointerface compared with the control Ti discs. Subsequent cell proliferation results also revealed a decrease in the number of viable cells on the TNT surfaces. The nanotopography and structural features along with the surface chemistry dictated the cellular response, with nanotubular surfaces (with and without polymer coating) impeding cell adhesion and proliferation. Our findings hold promise for the use of TNT-based cranial implants as a delivery system to prevent sutural bone growth for advanced craniosynostosis therapy.

The Craniofacial Biology Research Group in the School of Dentistry at The University of Adelaide is entering an exciting new phase of its studies of dental development and oral health in twins and their families. Studies of the teeth and faces of Australian twins have been continuing for nearly 30 years, with three major cohorts of twins recruited over that time, and currently we are working with twins aged 2 years old to adults. Cross-sectional data and records relating to teeth and faces of twins are available for around 300 pairs of teenage twins, as well as longitudinal data for 300 pairs of twins examined at three different stages of development, once with primary teeth, once at the mixed dentition stage, and then again when the permanent teeth had emerged. The third cohort of twins comprises over 600 pairs of twins recruited at around birth, together with other family members. The emphasis in this third group of twins has been to record the timing of emergence of the primary teeth and also to sample saliva and dental plaque to establish the timing of colonization of decay-forming bacteria in the mouth. Analyses have confirmed that genetic factors strongly influence variation in timing of primary tooth emergence. The research team is now beginning to carry out clinical examinations of the twins to see whether those who become colonized earlier with decay-forming bacteria develop dental decay at an earlier age. By making comparisons within and between monozygotic (MZ) and dizygotic (DZ) twin pairs and applying modern molecular approaches, we are now teasing out how genetic, epigenetic, and environmental factors interact to influence dental development and also oral health.

The analysis of microwear patterns, including scratch types and widths, has enabled reconstruction of the dietary habits and lifestyles of prehistoric and modern humans. The aim of this in vitro study was to determine whether an assessment of microwear features of experimental scratches placed on enamel, perpendicularly to the direction of grinding, could predict the grinding direction. Experimental scratches were placed using a scalpel blade on standardised wear facets that had been prepared by wearing opposing enamel surfaces in an electromechanical tooth wear machine. These control ‘baseline’ facets (with unworn experimental scratches) were subjected to 50 wear cycles, so that differential microwear could be observed on the leading and trailing edges of the ‘final’ facets. In Group 1 (n = 28), the ‘footprint’ microwear patterns corresponding to the known grinding direction of specimens in the tooth wear machine were identified. Then, they were used to predict the direction of tooth grinding blindly in the same sample after a 2-week intermission period. To avoid overfitting the predictive model, its sensitivity was also cross-validated in a new sample (Group 2, n = 14). A crescent-shaped characteristic observed in most experimental scratches matched the grinding direction on all occasions. The best predictor of the direction of grinding was a combined assessment of the leading edge microwear pattern and the crescent characteristic (82·1% in Group 1 and 92·9% in Group 2). In conclusion, a simple scratch test can determine the direction of tooth grinding with high reliability, although further improvement in sensitivity is desirable.

The increasing prevalence of gastroesophageal reflux disease (GERD) in children and adults, and of “silent refluxers” in particular, increases the responsibility of dentists to be alert to this potentially severe condition when observing unexplained instances of tooth erosion. Although gastroesophageal reflux is a normal physiologic occurrence, excessive gastric and duodenal regurgitation combined with a decrease in normal protective mechanisms, including an adequate production of saliva, may result in many esophageal and extraesophageal adverse conditions. Sleep-related GERD is particularly insidious as the supine position enhances the proximal migration of gastric contents, and normal saliva production is much reduced. Gastric acid will displace saliva easily from tooth surfaces, and proteolytic pepsin will remove protective dental pellicle. Though increasing evidence of associations between GERD and tooth erosion has been shown in both animal and human studies, relatively few clinical studies have been carried out under controlled trial conditions. Suspicion of an endogenous source of acid being associated with observed tooth erosion requires medical referral and management of the patient as the primary method for its prevention and control.

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.

In addition to its role as a remineralizing agent in preventing dental caries, recent evidence has shown that casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) can protect teeth against erosion. The aim of this study was to determine whether CPP-ACP could reduce enamel wear rates under severe erosive conditions simulating heavy attrition and gastric regurgitation.Enamel specimens were subjected to 10,000 wear cycles at a load of 100 N and pH 1.2 in a tooth wear machine. The machine was stopped every 2 min (160 cycles), and CPP-ACP in the form of a paste was applied for 5 min in experimental group 1. A paste with the same formulation but without CPP-ACP was applied in experimental group 2. No paste was applied in the control group.A linear mixed model analysis indicated that the mean wear rates in experimental group 1 (0.44+/-0.05 mm(3) per 1000 cycles) and in experimental group 2 (0.63+/-0.06 mm(3) per 1000 cycles) were significantly lower than that in the control group (0.92+/-0.11 mm(3) per 1000 cycles) (p0.05). The mean wear rate in experimental group 1 was also lower than that in experimental group 2 (p0.05). Wear facets in experimental groups 1 and 2 were noted to be smoother and more polished than those in the control group.Both remineralizing and lubricating properties of the paste containing CPP-ACP appear to contribute to wear reduction in enamel. These findings may lead to new strategies for the clinical management of tooth wear.