Sara Ghadimi; Mandana Tosifian; Ali Baghalian; Bahman Seraj
Abstract
Background: Crowding is one of the most prevalent types of malocclusion as well as a major problem in clinical orthodontics. It is essential to know the cause of crowding in order to achieve a better treatment.
Objectives: A longitudinal analysis of arch dimension changes in late primary and early mixed ...
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Background: Crowding is one of the most prevalent types of malocclusion as well as a major problem in clinical orthodontics. It is essential to know the cause of crowding in order to achieve a better treatment.
Objectives: A longitudinal analysis of arch dimension changes in late primary and early mixed dentition periods in children was designed and investigated the effect of eruption of precedence on the arch size in the samples under study.
Methods: This longitudinal study was carried out on 32 children aged 5.5 - 6.5 years who had no erupted permanent dentition. Impression was taken and the arch perimeter, depth and width as well as tooth size were measured by a digital calliper and a brass wire on casts. After eruption of the first permanent tooth, the second impression was taken; the above-mentioned parameters were measured on the second casts. Data were analysed by ANOVA test. Results: Four pattern of eruption of precedence were as follows: maxillary 1st molar, mandibular incisors, Mandibular 1st molars and simultaneous eruption of maxillary and mandibular 1st molars. With eruption of mandibular central incisors, inter canine width and overjet increased by 0.81 and 0.27 mm, respectively. The mandibular arch perimeter increased by 2.25 mm with simultaneous eruption of maxillary and mandibular permanent first molars. The maxillary arch perimeter increased by 1.25 mm and 1.50 mm with eruption of maxillary first molars and simultaneous eruption of maxillary permanent first molars, respectively.
Conclusions: Eruption precedence had a significant effect on changing mandibular inter canine width, maxillary arch perimeter, mandibular arch perimeter and overjet.
Bahman Seraj; Mandana Tosifian; Sara Ghadimi; Mohammad Javad Kharrazifard
Abstract
Background: Tooth size is an important factor that affects alignment of the teeth in the dental arch and occlusion development during dentition transition.
Objectives: This study was carried out to measure mesiodistal dimensions of primary teeth to provide standard for the tooth size. Knowledge of such ...
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Background: Tooth size is an important factor that affects alignment of the teeth in the dental arch and occlusion development during dentition transition.
Objectives: This study was carried out to measure mesiodistal dimensions of primary teeth to provide standard for the tooth size. Knowledge of such a standard of tooth size is significant for a better analysis of the space and more appropriate planning of orthodontic treatments.
Patients and Methods: The current study was conducted on 32 children, aged 5.5 - 6.5 years, in late primary dentition. The dental casts were prepared and the tooth size was measured by a digital caliper. The obtained data were analyzed by ANOVA and t-test.
Results: The mesiodistal width of primary central incisor in the upper left quadrant was larger than those of the rest of quadrants. Also, the mesiodistal widths of primary lateral incisors in the upper left quadrant, primary canines in the upper left quadrant, primary fist molars in the lower right quadrant and primary second molars in the lower left quadrant were larger than those of the other quadrants. Moreover, it was concluded that the mesiodistal diameter of permanent central incisors could be obtained according to the primary central incisors using the formula: 1.12 × (Deciduous central incisor width) + 1.27 = (Permanent central incisor width).
Conclusions: The findings of this study can be used as a base and standard for the measurement of primary dentition in Iranian children. Also, measurement of mesiodistal width of deciduous central incisors can be used to predict the mesiodistal width of permanent central incisors.
