Tea is the world's most popular non-alcoholic beverage. China and India are known to be the largest tea producing countries and recognized as the centers for the domestication of the tea plant ...(Camellia sinensis (L.) O. Kuntze). However, molecular studies on the origin, domestication and relationships of the main teas, China type, Assam type and Cambod type are lacking.
Twenty-three nuclear microsatellite markers were used to investigate the genetic diversity, relatedness, and domestication history of cultivated tea in both China and India. Based on a total of 392 samples, high levels of genetic diversity were observed for all tea types in both countries. The cultivars clustered into three distinct genetic groups (i.e. China tea, Chinese Assam tea and Indian Assam tea) based on STRUCTURE, PCoA and UPGMA analyses with significant pairwise genetic differentiation, corresponding well with their geographical distribution. A high proportion (30%) of the studied tea samples were shown to possess genetic admixtures of different tea types suggesting a hybrid origin for these samples, including the Cambod type.
We demonstrate that Chinese Assam tea is a distinct genetic lineage from Indian Assam tea, and that China tea sampled from India was likely introduced from China directly. Our results further indicate that China type tea, Chinese Assam type tea and Indian Assam type tea are likely the result of three independent domestication events from three separate regions across China and India. Our findings have important implications for the conservation of genetic stocks, as well as future breeding programs.
ABSTRACT
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.
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.
Abstract 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.
Structured
Objectives
Glypican 1 (GPC1) and glypican 3 (GPC3) are bone co‐regulators that act downstream in many of the signalling pathways associated with craniosynostosis. Morphometric data from ...GPC‐knockout mice were analysed to determine whether elimination of GPC1 and GPC3 genes would alter mandibular morphology.
Setting and sample population
The murine model included five male and five female mandibles in each of GPC1‐knockout, GPC1/GPC3‐knockout and wild‐type (control) groups. Female GPC3‐knockout mice had a very high rate of perinatal lethality, and therefore, only five males were included in this group.
Methods
The mandibular morphology of GPC1‐knockout (n=10), GPC3‐knockout (n=5), GPC1/GPC3‐knockout (n=10) and wild‐type (n=10) mice was compared by analysing five landmark‐based linear dimensions: anterior and posterior lengths, as well as ascending, descending and posterior heights. Measurements were recorded on three‐dimensional micro‐CT reconstructions.
Results
GPC3‐knockout mandibles were larger than wild‐type mandibles for all dimensions (P<.05). Mandibular heights were more affected than lengths. A decreasing trend of mandibular dimensions across the mouse groups (GPC3‐knockout>GPC1/GPC3‐knockout>GPC1‐knockout=wild‐type) (P<.05) indicated that an increase in mandibular size was associated with increased GPC3 expression, but not GPC1.
Conclusions
Alterations in GPC3 expression are likely to mediate changes to mandibular size in craniosynostosis. These findings have potential future applications in the prevention and treatment of craniosynostosis and associated craniofacial dysmorphology.
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.
Chronic orofacial pain of neuropathic origin can present diagnostic and management dilemmas to dental practitioners and also affects the patient's quality of life. Intracranial aneurysms are a ...potential cause of stroke (e.g. sub‐arachnoid haemorrhage) that is usually associated with, 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 ruled out odontogenic pain, TMD and other more common types of facial pain. Magnetic resonance imaging revealed a 7 × 6 mm aneurysm in the right middle cerebral artery (MCA) 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 reported. To our knowledge, this is the first case of facial neuralgia associated with an aneurysm in the MCA which emphasizes the importance of a multidisciplinary approach in the diagnosis and management of unusual cases of chronic orofacial pain.
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.
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.
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.
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