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Mechanical Stress and Bone Remodeling
Published in Wilson Harvey, Alan Bennett, Prostaglandins in Bone Resorption, 2020
Prior to tooth eruption, the growing tooth crown expands but does not move towards the oral cavity until the root begins to form. Two main activities, summarized by Davidovitch40 in a working hypothesis, appear to be an increase in pressure on the bone at the apex and resorption occlusal to the crown. The apical pressure is postulated to come from proliferating pulpal cells synthesizing glycosaminoglycans (hydrophilic molecules which would swell) and proliferating periodontal ligament cells. Resorption at the crown could be stress induced, perhaps by contraction of periodontal ligament fibers or pressure from the expanding dental sac, or induced by the enamel epithelium cells via associated monocytes. Clearly, the bone occlusal to the erupting tooth undergoes more net resorption than bone at the apex.
Genetics of Endocrine Disorders and Diabetes Mellitus
Published in George H. Gass, Harold M. Kaplan, Handbook of Endocrinology, 2020
Bess Adkins Marshall, Abby Solomon Hollander
Newborns with growth hormone deficiency usually have normal length and weight. They may present with hypoglycemia or prolonged hyperbilirubinemia.2 Boys will often have a micropenis.3 In children with GH deficiency, the facial bones develop slowly, leading to protrusion of the frontal bones and poor development of the bridge of the nose. Tooth eruption is delayed. The hair is thin and the nail growth is poor. The voice is often high-pitched. The linear growth is retarded, and the child will often appear mildly obese and cherubic.2 These features can be corrected via therapy with recombinant human growth hormone (hGH). The discovery of the GH gene locus on human chromosome 17 made possible the development of recombinant hGH. In the last several years, much has been elucidated about the control of GH gene expression. The remainder of this section will focus on growth hormone gene expression, its regulation by transcription factors, and clinical examples of abnormalities of these processes.
Growth Mechanisms of the Mandible
Published in D. Dixon Andrew, A.N. Hoyte David, Ronning Olli, Fundamentals of Craniofacial Growth, 2017
Due to the filling-in phenomenon tooth eruption has also an important compensatory role in the development and maintenance of a normal relationship between the teeth. For instance, in association with posterior rotation of the mandible, the anterior part is lowered more than the posterior part. Without increased eruption of anterior teeth, which are now free to erupt, this would result in an anterior open-bite. (Björk, 1963; Solow, 1980; Lundström and Mac William, 1984). The clinician is also accustomed to using the filling-in phenomenon as one means of treating an anterior open bite, by inhibiting eruption of posterior teeth by exerting increased pressure on them with special chewing gums (Ingervall and Bitsanis, 1987). The effect, nevertheless, seems to be limited. Increased activity of the masticatory muscles that are attached to the mandible has been used to increase mechanical stress on the teeth, by occlusal splints over the molars (McNamara, 1977; Altuna and Woodside, 1985). Direct pressure on the teeth has been exerted using the repelling forces of magnets, with final anchorage coming from the masticatory muscles keeping the teeth close to each other (Dellinger, 1986; Woods and Nanda, 1988; Kiliaridis et al., 1990).
Vitamin D deficiency is a risk factor for delayed tooth eruption associated with persistent primary tooth
Published in Acta Odontologica Scandinavica, 2021
Thaís Aparecida Xavier, Isabela Ribeiro Madalena, Raquel Assed Bezerra da Silva, Léa Assed Bezerra da Silva, Marcelo José Barbosa Silva, Andiara De Rossi, Erika Calvano Küchler, Sandra Yasuyo Fukada
Tooth development [22] and eruption [23] are complex processes that also involve alveolar bone resorption and an eruption pathway formation [23]. Disturbances in dental development can lead to a persistent primary tooth (PPT) and delayed tooth eruption (DTE). PPT occurs when a primary tooth is retained beyond the regular exfoliation time. PPT can cause malocclusions, periodontitis, ankylosis [24] and a severe impact on patient dissatisfaction [25]. The molecular mechanism underlying PPT occurrence has not been fully explained, but it is known that PPT can lead to DTE of the permanent tooth [26]. DTE is the emergence of a tooth into the oral cavity at a delayed time than expected according to sex and ethnic differences [27]. The failure of dental emergence in the oral cavity influences the paediatric and orthodontic treatment plan, impacting a patient's oral health [27,28].
Incidence of impacted teeth requiring fenestration, traction, and orthodontic treatment in Japan
Published in Orthodontic Waves, 2021
Haruhisa Nakano, Chie Tachiki, Takuma Sato, Michiko Tsuji, Mikiko Mano, Yusuke Minoura, Kiyofumi Ogawa, Yasuyo Nomura, Takemi Soya, Yutaka Koshio, Ken Miyazawa, Noriyoshi Shimizu, Keiji Moriyama
It is clear that the diagnosis of impacted teeth (distinguishing them from unerupted teeth) requires a detailed analysis. Specifically, an impacted tooth is one that would satisfy one or more of the following criteria: Cause root resorption of the adjacent permanent teeth.Eruption is hindered due to lesions such as odontomas.Spontaneous eruption is not observed after the average age of permanent tooth eruption, and the development of tooth root is complete.Spontaneous eruption is determined as difficult by follow-up observation, such as panoramic radiographs over time.① When the tooth axis or tooth germ position is significantly abnormal.② When there is a secondary disorder such as root curvature.③ When there is no tendency to erupt, even after the average permanent tooth eruption age (Table 8).
The microbiota of the mother at birth and its influence on the emerging infant oral microbiota from birth to 1 year of age: a cohort study
Published in Journal of Oral Microbiology, 2019
Eimear Hurley, David Mullins, Maurice P. Barrett, Carol Anne O’Shea, Martin Kinirons, C. Anthony Ryan, Catherine Stanton, Helen Whelton, Hugh M. B. Harris, Paul W. O’Toole
At phylum level (see Figure 8(a)), the composition of the oral microbiota between week 1 and 1 year is different (p < 0.001), while only from 6 months do we see the significance begin to emerge. The infant oral saliva microbiota is dominated from birth to 6 months by Firmicutes and is relatively stable in its abundance from week 1 to 6 months (see Figure 8(a)). Firmicutes levels between week 1 and week 8 are similar with relative abundances at week 1 (82.3%), week 4 (87.3%) and 8 weeks (81.1%). Only after 8 weeks does the abundance of Firmicutes begin to decrease, from 6 months (60.2%) until 1 year (33.7%), and this coincides with an increase in the abundances of Proteobacteria at 1 year (25.6%) (p < 0.0001) and Bacteroidetes (16.7%). These changes from 6 months to 1 year may be due to the influence of tooth eruption and introduction of solid foods, which typically occurs at this time.