IADR Abstract Archives
Maxillomandibular Ratio: Retrospective Cohort Cephalometric Study Of Untreated Caucasian Subjects.
Objectives: To analyze the evolution of maxillary and mandibular proportional growth in length expressed as the maxillomandibular ratio (RMxMd) in Northamerican Caucasian growing children. Also, to compare the differences in the values obtained from the RMxMd according to sagittal skeletal classification for each stage of cervical maturation, and to assess the predictive value of RMxMd for skeletal classification Northamerican Caucasian children.
Methods: A longitudinal sample of the AAOF records (1) was obtained with profile teleradiographies of 231 patients (101 Class I, 83 Class II and 47 Class III), each one with at least three timepoints, including one prepuberal and postpuberal record according to their cervical maduration stage (CVS) (2). No statistical differences were found by sex, so the sample was treated unified. The skeletal Class was determined with the ANB angle at the last available record. RMxMd were recorded as maxillary length (Condylion- A point) divided by mandibular length (Condyleon- Gnation). A normal distribution of the data was verified with the Shapiro Wilk test. Descriptive statistics were obtained. ANOVA Test and post- hoc Bonferroni Test were used, and the predictive value of the RMxMd was evaluated.
Results: RMxMd decreased with growth. The RMxMd's mean was significantly different (P value ≤ 0.05) among all skeletal classes and maturation stages. Class II had the greatest values, then Class I and finally Class III. At stages 1 and 2 of CVS, the positive predictive value of the RMxMd for Class III is 73%, and at stage 3 it is 77% for Class II.
Conclusions: The RMxMd has a distinct evolution for each skeletal class starting from the initial prepubertal measurements. The RMxMd correctly classifies Class III individuals at prepubertal stages, and Class II individuals at circumpuberal stages, when the orthopedic treatment is more effective. RMxMd can become useful diagnostic tool for timely treatment of skeletal dysplasias.
Methods: A longitudinal sample of the AAOF records (1) was obtained with profile teleradiographies of 231 patients (101 Class I, 83 Class II and 47 Class III), each one with at least three timepoints, including one prepuberal and postpuberal record according to their cervical maduration stage (CVS) (2). No statistical differences were found by sex, so the sample was treated unified. The skeletal Class was determined with the ANB angle at the last available record. RMxMd were recorded as maxillary length (Condylion- A point) divided by mandibular length (Condyleon- Gnation). A normal distribution of the data was verified with the Shapiro Wilk test. Descriptive statistics were obtained. ANOVA Test and post- hoc Bonferroni Test were used, and the predictive value of the RMxMd was evaluated.
Results: RMxMd decreased with growth. The RMxMd's mean was significantly different (P value ≤ 0.05) among all skeletal classes and maturation stages. Class II had the greatest values, then Class I and finally Class III. At stages 1 and 2 of CVS, the positive predictive value of the RMxMd for Class III is 73%, and at stage 3 it is 77% for Class II.
Conclusions: The RMxMd has a distinct evolution for each skeletal class starting from the initial prepubertal measurements. The RMxMd correctly classifies Class III individuals at prepubertal stages, and Class II individuals at circumpuberal stages, when the orthopedic treatment is more effective. RMxMd can become useful diagnostic tool for timely treatment of skeletal dysplasias.
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