IADR Abstract Archives
Morphological changes of different phenotypes during craniofacial growth.
Objectives: The growth pattern of hyperdivergents craniofacial phenotype is established early at 6 years age1. Is reported that 64% of hyperdivergents of 6 years, remain at 15 with the same phenotype, with a 25% worsening2. These patients are difficult to treat in orthodontics, so it is important to diagnose them early and try to intercept this growing pattern. The aim of this study is to describe the morphological changes that occur during growth in normo (N), hypo (A) and hyperdivergent (H) phenotypes.
Methods: 316 teleradiographs were measured cephalometrically. This study was approved by the scientific and ethical board of Universidad de los Andes, Chile. 27 cephalometric variables were measured in 6 groups of cervical maturation stages3. A descriptive analysis (measures of central tendency and dispersion) and an ANOVA between the phenotypes N, A and H within each maturation group for each variable were performed (SPSS®).
Results: Significant differences were found in all skeletal maturation groups except group 6 for lack of a minimum of subjects. The most important and discussed variables were: Goniac angle (P= 0,000), ramus height (p= 0,004), chin projection (p=0,021), ANB (p= 0,009), SNA (p= 0,008), SNB (p= 0,000) (table 1).
Conclusions: Goniac angle is higher in hyperdivergent during growth, while mandibular ramus is significantly smaller. Chin projection in hyperdivergent is significantly lower than the rest of phenotypes but, after pubertal peak there is an increase in hypodivergents, probably because mandibular rotation during its growth2,4,5 (while hyperdivergent tends to worsen after the peak). A difference in ANB during the peak between hypo and hyperdivergent was observed, in which turns to be greater in hyper. SNA and SNB decreases significantly in hyperdivergents as it is stablished in literature2, but after acceleration and pubertal peak we see how in hypodivergent increase SNB significantly while hyperdivergents remains constant.
Methods: 316 teleradiographs were measured cephalometrically. This study was approved by the scientific and ethical board of Universidad de los Andes, Chile. 27 cephalometric variables were measured in 6 groups of cervical maturation stages3. A descriptive analysis (measures of central tendency and dispersion) and an ANOVA between the phenotypes N, A and H within each maturation group for each variable were performed (SPSS®).
Results: Significant differences were found in all skeletal maturation groups except group 6 for lack of a minimum of subjects. The most important and discussed variables were: Goniac angle (P= 0,000), ramus height (p= 0,004), chin projection (p=0,021), ANB (p= 0,009), SNA (p= 0,008), SNB (p= 0,000) (table 1).
Conclusions: Goniac angle is higher in hyperdivergent during growth, while mandibular ramus is significantly smaller. Chin projection in hyperdivergent is significantly lower than the rest of phenotypes but, after pubertal peak there is an increase in hypodivergents, probably because mandibular rotation during its growth2,4,5 (while hyperdivergent tends to worsen after the peak). A difference in ANB during the peak between hypo and hyperdivergent was observed, in which turns to be greater in hyper. SNA and SNB decreases significantly in hyperdivergents as it is stablished in literature2, but after acceleration and pubertal peak we see how in hypodivergent increase SNB significantly while hyperdivergents remains constant.
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