Introduction:
The eruption of the permanent maxillary incisors in a child at the age of 6 to 7 years is a major relief for most of the concerned parents regarding their child’s permanent dentition. Although the root development of the tooth is the fundamental parameter for correct and timely eruption, positional deviations, ectopic eruptions, disturbances, or supernumerary teeth can be a source of the delayed eruption. Read the article to know the causes, research models, and the factors causing the eruption of maxillary central incisors in children.
Is Delayed Eruption of Upper Central Incisors a Concern?
Delayed upper central incisors may not only be a source of reduced self-esteem for the growing child but can also create concerns to anxious parents who are worried if the delay extends past the age of 7 years. Though delayed eruption is not uncommon, delayed eruption due to generalized retarded eruption of teeth, abnormal tooth-to-tissue ratio, or supernumerary teeth, as well as in certain disorders like cleidocranial dysostosis, cleft lip, and cleft palate, is concerning and uncommon. Hence, the parent or guardian should approach the dental surgeon for timely dental and surgical intervention to confirm with the dental surgeon firstly if the permanent central incisors are present or not, and if they are, then they have to discuss how to initiate its eruption into the oral cavity as the maxillary incisors play an extremely esthetic role in shaping the child’s facial features and confidence levels.
According to research models, masseter muscle thickness (a muscle of mastication), maximum occlusal force, periodontal health, muscular factors, and antagonist (opposing) teeth are the few main influential factors for the incisors to erupt at the right time into the oral cavity.
How Is Masseter Muscle Thickness Measured?
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The subjects (children) are seated in an upright position without leaning on a headrest.
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The measurements are performed at the thickest part of the masseter muscle that is near the occlusal plane level.
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Maximum occlusal force (MOF) and the maximum voluntary molar occlusal forces are measured using a bite fork strain gauge with the subjects being seated in an upright position without leaning on a headrest.
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The bite fork is covered by a 2 mm thick elastic material and then placed between the first molars alternating twice on each side. The masseter muscle thickness and maximum muscle thickness alone are usually considered as parameters that can assess the masticatory muscular functionality and are inversely related to the amount of eruption in the natural incisors.
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Clinical crown lengthening is the most important parameter considered for assessing periodontal health and hence is another important factor relating to the amount of eruption.
What Is the Role of Muscular Factors and Opposing Teeth in Eruption?
Continuous eruption of maxillary incisors is linked to the functional capacity of the individual since individuals with a thick masseter show a lower amount of continuous eruption over a 10-year period when compared with individuals with weak masseter muscles. The continuous eruption is a never-ending process even in adulthood, as shown by many studies.
Weaker muscles have a slight effect in exhibiting tooth eruption, while stronger muscles partially counteract eruption. Therefore, the masticatory or chewing muscles regulate the eruption rate only when opposing teeth are in contact during swallowing, chewing, and parafunction cases such as clenching. The periodontal status played an important role in the tooth-eruption phenomenon.
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Periodontal and Muscular Factors: They seem to be related to eruption patterns in the long term (10 years) in the maxillary central and lateral incisors. The periodontal status of the implant and adjacent teeth has been considered as the main crucial factor for implant stability and esthetics and may also influence the eruption of adjacent natural teeth, accentuating the infraocclusion as well as the appearance of single anterior implants. The muscular capacity of individual patients may also be considered as a factor that influences the long-term esthetics of the implant-supported crown by regulating the eruption rate of the natural maxillary incisors.
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Opposing Teeth Role: A possible reason for the variation in the eruption rates may be the difference in the magnitude of the occlusal forces acting on teeth with or without antagonists; the latter reaction a zero level. In healthy subjects, the level of the occlusal forces may vary substantially between individuals, mainly due to the different muscular capacities of their masticatory muscles. Thus the hypothesis that the variability of the occlusal forces can lead to different continuous eruption rates among individuals remains a major determinant in the dental literature.
When Is a Dental Implant Needed?
The continuous eruption occurs both in the presence and absence of the opposing teeth, although it seems to be greater in the unopposed teeth. It is well known that continuous physiological eruption of teeth goes on until adult life and is very likely never to cease. This phenomenon may have a negative esthetic implant with infraocclusion of implant-supported crowns in the smile area. The central and lateral incisors are usually identified as the teeth that undergo the greatest changes in terms of eruption. Dental implantation is the best option or choice of replacing the gap in children with missing central incisor tooth bud or congenital absence of the tooth bud.
Though this phenomenon is uncommon, the dentist can confirm the same and make the child opt for a dental implant and prosthesis instead. However, if the surgeon does not crosscheck via a CBCT (cone beam computed tomography) or opt X-ray modality, then there is room for definite error as dental implants are not strictly advisable for children and young adolescents below 18 years of age, given that the implant stabilization in bone is not possible because skeletal maturity is not attained.
Also, the permanent tooth bud can be hampered from eruption if implantation is done in the central incisor region without confirming its presence. Hence implantation is indicated only in patients with missing central incisors and preferably after attaining skeletal maturity (above 17 or 18 years of age). So a bridge, space maintainer, or a partial denture would be a safer option till then.
Conclusion:
Once the dental surgeon understands or analyses the cause of the child’s delayed eruption or the unerupted maxillary incisors, surgical management or removal of unwarranted factors can potentially prevent delayed eruption of the maxillary central incisors.
