Prevalence of malocclusion and occlusal traits in the early mixed dentition in Shanghai, China

Abstract

BackgroundEpidemiological data on malocclusion among Chinese children are scant. The aim of this study was to provide detailed information on the prevalence of malocclusion in early mixed dentition children in Shanghai, China.MethodsA cross-sectional survey was conducted from September 2016 to April 2017, and 2,810 children aged 7- to 9- years were selected from 10 primary schools by cluster random sampling. Several occlusal parameters, including Angle molar relationship, overjet, overbite, open bite, anterior and posterior crossbite, midline displacement, scissors bite, and teeth crowding and spacing, were clinically registered by five calibrated orthodontic dentists.ResultsWe found that 79.4% children presented one or more occlusal anomalies. Angle Class I, Class II and Class III molar relationship were recorded in 42.3%, 50.9% and 5.9% of the sample, respectively. The proportion of Class III increased from 5.0% at age 7 to 7.8% at age 9. In the sagittal plane, increased overjet >3 mm was observed in 40.8% subjects, while the prevalence of severe overjet (>8 mm), anterior edge-to-edge (zero overjet) and anterior crossbite were 5.2%, 8.1% and 10.5%, respectively. Vertically, deep overbite >2/3 overlap was found in 6.2% of the children and open bite in 4.3%. Boys exhibited a higher rate of overbite than girls. For the transversal occlusal anomalies, 36.1% of the children had a midline displacement, which was followed by posterior crossbite (2.6%) and scissors bite (1.0%). Teeth space discrepancies were also common anomalies and anterior crowding (>2 mm) affecting 28.4% of the children, while anterior spacing (>4 mm) affecting 9.5%. Girls showed a higher prevalence of anterior crowding and a lower frequency of teeth spacing than boys.ConclusionsOur study demonstrated that malocclusion is prevalent among children in the early mixed dentition, and more health resources should be warranted to meet the challenge of prevention or early intervention of malocclusion.

Prevalence of Malocclusion Among Yemeni Children of Primary Schools

“…By comparing with other studies, this result is much higher than that found by Disha et al, 24 study was crowding seen in 30.0% of school children (Table 5). This finding is almost in agreement with that of Almeida et al, 21 (31.59%), Al-Zubair and Ghandour, 16 (31.4%), Al-Zubair and Al-Almulla, 17 (30.4%), and by Yu et al, 26 (28.4%). However, the number of crowding in this study is much lower than that reported by Souza et al, 28 (49.6%), Brito et al, 14 (45.5%), and by Romano et al, 19 (52.6%).…”

“…By comparing the result of this study to other studies, there was almost an agreement with the following reported studies 14 80.84%, 19 86.6%, and 20 83.3%. 26 79.4%. The variation in the prevalence of malocclusion can be attributed to the differences in the age ranges of the populations studied, the number of subjects examined and differences in the registration methods which are probably the most important factors explaining these variations 9 .…”

“…[23][24][25][26][27][28] . On the other hand, few studies by Gonçalves et al,33 ; Freitas et al,34 ; and by Yu et al,26 emphasized the predominance of Class II, in comparison with relation Class I and Class III. This…”

Fracture strength of endodontically treated lateral incisors restored with new zirconia reinforced rice husk nanohybrid composite

“…First, the forces generated in vivo during mastication vary in magnitude, speed and direction, whereas force applied in present study was set at a constant speed and direction. Second, considering the large variation in the degree of incisor inclination among the general population ( 32 , 33 ), it is difficult to make a definite assumption based on current results since the fracture strength of the teeth might differ according to different incisor relationships. Therefore, it is impossible to directly extrapolate the results obtained in a controlled lab study to clinical situation necessitating.…”

Perception of Smile Aesthetics of Patients with Anterior Malocclusions and Lips Influence: A Comparison of Dental Professionals’, Dental Students,’ and Laypersons’ Opinions

“…Anterior malocclusions affecting the perimeters of the dental arches include crowding and spacing. Crowding frequently occurs in the anterior segments of the dental arches, while spacing is less common [ 10 ]. Different classifications of crowding and spacing have been reported, but according to the most common ones, mild crowding is defined as a crowding of 0–3 mm, moderate as 4–8 mm, and severe as >8 mm [ 11 ].…”