Question

explain how the sequence of eruption of the permanent dentition plays a role in the establishment of a normal occlusion

Answer 1

Occlusion is defined as the contact relationship of the maxillary and mandibular teeth when the mouth is fully closed.Occlusion is defined as the contact relationship of the maxillary and mandibular teeth when the mouth is fully closed. Occlusion is important because it can influence a person’s facial profile and also the health of the oral cavity. Occlusions that are not ideal may be improved with dental treatments such as orthodontics.

The occlusion of the primary dentition is completely established by the age of 3 years and lasts until about 6 years of age when the first permanent tooth begins to erupt. Understanding the association between morphological aspects in the primary dentition and its transition to the permanent dentition provides the possibility of predicting the final permanent occlusion. The anteroposterior relation of maxillary and mandibular permanent molars is an important criterion for recognition of malocclusions. This determines the necessity of interceptive orthodontics.

Childhood is the mirror in which the propensities of adulthood are reflected; similarly the type of occlusion in primary dentition predicts the occlusion of the permanent dentition. The understanding of the anteroposterior changes that occur in the occlusion between the primary and permanent dentition is crucial for the clinicians involved in early orthodontic treatment. Normal occlusion in primary teeth has the following characteristics: spacing between anterior teeth, primate spaces, low overjet and overbite, flush terminal plane molar relation, and ovoid arch form. The deviations in occlusion in primary dentition would be carried to succeeding permanent dentition and to a more pronounced degree.

Spacing is a common condition in the primary dentition and constitutes a very important feature of the dentition as it is an indicator of favorable development of permanent occlusion. Spacing often presents between all anterior primary teeth with the most marked spaces present being mesial to canines in the maxilla and distal to canines in the mandible. These are called primate spaces. The secondary or developmental spaces which are commonly found between the incisors are termed physiological spaces.The incidence of spacing in primary dentition varies from 42.9% to 98%. Perhaps lack of spacing suggests severe risk for crowding in the permanent dentition. Spacing is more common in the maxilla than in the mandible and spaces are observed more among boys rather than girls.Many observational studies relating to the spacing and occlusion of the primary dentition have confirmed that the occlusal characteristics vary among populations and ethnic groups.