Further Studies of a Model for the Etiology of Anomalies of Tooth Number and Size in Humans

Brook, Alan; Elcock, Claire; Al-Sharood, M. H.; McKeown, H. F.; Khalaf, Khaled; Smith, Richard N.

doi:10.1080/713713492

Cited by 34 publications

(24 citation statements)

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“…The decrease in size was directly proportional to the degree of severity of hypodontia with the mean size values decreasing progressively from the control subjects through mild, moderate and then severe hypodontia. This is consistent with the results of previous studies that have employed traditional measurement techniques (Garn and Lewis, 1970; Baum and Cohen, 1971; Rune and Sarnas, 1974; Brook, 1984; Ooshima et al, 1996; Schalk-van der Weide and Bosman, 1996; Brook et al, 2002, 2009a; McKeown et al, 2002). Other researchers have reported that the degree of size reduction was associated with the degree of the severity of the hypodontia (Rantanen, 1956; Alvesalo and Portin, 1969; Garn and Lewis, 1970; Lavelle, 1970; Rune and Sarnas, 1974; Brook, 1984; Brook et al, 2009b; Yaqoob et al, 2011; Mirabella et al, 2012).…”

Section: Discussionsupporting

confidence: 91%

3D-Geomorphometrics tooth shape analysis in hypodontia

et al. 2014

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Assessment of tooth morphology is an important part of the diagnosis and management of hypodontia patients. Several techniques have been used to analyze tooth form in hypodontia patients and these have shown smaller tooth dimensions and anomalous tooth shapes in patients with hypodontia when compared with controls. However, previous studies have mainly used 2D images and provided limited information. In the present study, 3D surface-imaging and statistical shape analysis were used to evaluate tooth form differences between hypodontia and control patients. Eighteen anatomical landmarks were recorded on the clinical crown of the lower left first permanent molar of 3D scanned study models of hypodontia and control subjects. The study sample group comprised of 120 hypodontia patients (40 mild, 40 moderate, and 40 severe hypodontia patients) and 40 age- and sex-matched controls. Procrustes coordinates were utilized to scale and superimpose the landmark coordinate data and then were subjected to principal component analysis (PCA). Subsequently, differences in shape as well as size were tested statistically using allometric analysis and MANOVA. Significant interaction was found between the two factor variables “group” and “sex” (p < 0.002). Overall expected accuracies were 66 and 56% for females and males, respectively, in the cross-validated discriminant-analysis using the first 20 PCs. Hypodontia groups showed significant shape differences compared with the control subjects (p < 0.0001). Significant differences in tooth crown shape were also found between sexes (p < 0.0001) within groups. Furthermore, the degree of variation in tooth form was proportional to the degree of the severity of the hypodontia. Thus, quantitative measurement of tooth shape in hypodontia patients may enhance the multidisciplinary management of those patients.

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Section: Discussionsupporting

confidence: 91%

3D-Geomorphometrics tooth shape analysis in hypodontia

et al. 2014

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“…Twin studies suggest that tooth size is predominantly under genetic control . Other family‐based studies suggest that relatives of individuals with hypodontia have an increased tendency for missing and smaller teeth in general and there is evidence that palatally impacted canines have genetic component…”

Section: The Aetiology Of Malocclusionmentioning

confidence: 99%

Myofunctional therapy and prefabricated functional appliances: an overview of the history and evidence

Wishney

Darendeliler

Dalci

2019

Australian Dental Journal

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Malocclusion represents the clinically observable endpoint of numerous genetic and environmental influences. Oral Myofunctional Therapy (OMT) aims to treat malocclusions by improving the oral environment through re-education of musculature and respiratory patterns. Although the concept of OMT has existed since the early part of the 20th Century, many of its purported benefits for the treatment of malocclusion remain undemonstrated in the scientific literature. However, a more recent application of OMT for the treatment of Obstructive Sleep Apnoea (OSA) suggests some benefits, although more research is needed to clarify this effect. Prefabricated functional appliances (PFAs) are sometimes advocated as part of myofunctional training programs. In the past decade, controlled clinical investigations have demonstrated that PFAs can improve Class II Division 1 malocclusions in compliant patients. Compared with traditional functional appliances, PFAs might be more cost effective; however, this must be balanced against compliance problems and evidence suggesting that other types of functional appliances might give better treatment results in a comparable time frame.Abbreviations and acronyms: OMT = Oral Myofunctional Therapy; PFA = prefabricated functional appliance; OSA = Obstructive Sleep Apnoea; AHI = apnoea hypopnoea index; RCT = randomised controlled trial.

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“…Investigations at molecular and cellular levels have identified the fundamental mechanisms which were predicted from the model based on statistical analysis of clinical epidemiological data [9,74,75]. When considered in conjunction with clinically based investigations [76][77][78][79], it becomes clear that many dental phenotypes are inter-related and that they are influenced by a combination of genetic, environmental and epigenetic factors. Indeed, common dental anomalies such as missing or extra teeth can be viewed as representing the extremes of a continuous spectrum of co-variation for which there are likely to be common underlying developmental mechanisms.…”

Section: Locating and Identifying Genes Affecting Dental Developmentmentioning

confidence: 99%

Genetic, environmental and epigenetic influences on variation in human tooth number, size and shape

et al. 2011

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The aim of this review is to highlight some key recent developments in studies of tooth number, size and shape that are providing better insights into the roles of genetic, environmental and epigenetic factors in the process of dental development. Advances in molecular genetics are helping to clarify how epigenetic factors influence the spatial and temporal regulation of the complex processes involved in odontogenesis. At the phenotypic level, the development of sophisticated systems for image analysis is enabling new dental phenotypes to be defined. The 2D and 3D data that are generated by these imaging systems can then be analysed with mathematical approaches, such as geometric morphometric analysis. By gathering phenotypic data and DNA from twins, it is now possible to use 'genome-wide' association studies and the monozygotic co-twin design to identify important genes in odontogenesis and also to clarify how epigenetic and environmental factors can affect this process. Given that many of the common dental anomalies affecting the human dentition are interrelated, apparently reflecting pleiotropic genetic effects, the discoveries and new directions described in this paper should have important implications for clinical dental practice in the future.

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Further Studies of a Model for the Etiology of Anomalies of Tooth Number and Size in Humans

Cited by 34 publications

References 0 publications

3D-Geomorphometrics tooth shape analysis in hypodontia

3D-Geomorphometrics tooth shape analysis in hypodontia

Myofunctional therapy and prefabricated functional appliances: an overview of the history and evidence

Genetic, environmental and epigenetic influences on variation in human tooth number, size and shape

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