The importance of upper first permanent molars position for the orthognatic occlusion

Abstract

Development of the dental arches and occlusion in permanent dentition can be divided into several stages and has to be observed regularly. The first permanent molar eruption is related to the onset of significant changes in the developing occlusion. Although this tooth is seen as the "key to occlusion" its value as an anchorage is debatable. The aim of the article is to study the correct position of the upper first molars in the two planes of spacethe sagittal and transverse planes. In this article the position of the first upper molar is examined with the aid of diagnostic records, such as study cast, orthopantomogram (OPG), and lateral cephalometrics. A literature review includes Bulgarian and foreigner authors. Angle, who in 1899 referred to the maxillary first permanent molars as the "key to occlusion", was the first to mention their importance within the dentition. According to Angle, the line passing through the middle of the mesiobuccal cusp of the upper first molar coincides with the line passing through the buccal groove of the lower first molar. After Angle, other authors have discussed the position of upper molars from different point of view, such as their relation or position in the maxilla, anteroposterior axial inclination and rotation. As indicated by Lamons and Holmes molar rotations commonly exist in Class II malocclusions. The molars are usually rotated around an axis lingual to their central fossae. In an ideal occlusion the buccal surfaces of the upper first molars are usually parallel to each other On the OPG Kurol and Bjerklin measured the axial mesial inclination of upper first molar. The tipping of the molars is measured by the angle formed between the tangent line to the mesial surfaces of the root and crown and the line through the lower margins of the left and right orbits. According to Sassouni, the mesial contour of upper first molar should to lie on the 4th arc-the temporal arc. If the molar is anterior to this arc, a treatment with distalization could be initiated. The temporal arcnasion distance measured on the radius is equal to the distance from point ANS to the upper first molar. The position of the upper first molar varies with the position of the upper central incisors. The basic hypothesis is that if the upper first molar has a fixed position in the face, any increase in the total upper dental arch length will be transferred to the incisor area. Any change in the anteroposterior position of the upper first molar could influence the position of the mandibular-leading to Class II malocclusion. Ricketts pointed out that the average distance from the pterygoid vertical (PTV) to the distal surface of upper first molar is the sum of the age of the patient The Importance of Upper First Permanent Molars Position for the Orthognatic Occlusion

Prevalence of Caries in Permanent First Molars Among Children with and Without Caries on Primary Teeth- A Retrospective Study

“…Dental neglect and stress levels can result in less salivary secretion leading to caries formation. Studies have shown that malondialdehyde levels are at a high level in saliva which increases the risk for development of ECC (World Health Organization WHO., 1997;McDonald and Sheiham, 1992;Taani and Quteish, 2004;Gurunathan and Shanmugaavel, 2016;Aishwarya and Gurunathan, 2017;Subramanyam et al, 2018;Ivanova et al, 2018;Krishnaswamy et al, 2020).…”

“…occlusal caries was seen among young children and proximal caries among older children. Traumatic injuries can also result in fractured teeth and infections that can lead to caries formation (Edward, 1997;Lith et al, 2002;Hopcraft and Morgan, 2006;Christabel and Gurunathan, 2015;Packiri et al, 2017;Ravikumar et al, 2017;Ivanova et al, 2018;Krishnaswamy et al, 2020).…”