The Frankfort-mandibular plane angle (FMA) is formed by the intersection of the Frankfort horizontal plane and the mandibular plane. This angle can be traced and measured by means of a diagnostic overlay. An FMA of 25 +/- 5 degrees is within normal range.

A high FMA usually shows an increase in the alveolar bone growth and a low FMA has a decrease in the bone growth. Low angle patients typically have flat, broad palatal vaults, shallow buccal vestibules, and high muscle attachments.

Dec 1, 1976 · The Frankfort-mandibular plane angle (FMA) is formed by the intersection of the Frankfort horizontal plane and the mandibular plane. This angle can be traced and measured by means of a diagnostic overlay. An FMA of 25 ± 5 degrees is within normal range.

A “high-angle” patient is one with an FMA of 30 degrees or more, whereas a “low-angle” patient is one with an FMA of 20 degrees or less (Fig. 3). With respect to vertical facial types, a high FMA is characterized by open-bite skeletal patterns and a low FMA by closed-bite skeletal patterns.

The Frankfurt- mandibular plane angle [Figure 1] is an angle formed by the intersection of the Frankfort horizontal plane and the mandibular plane. The sig-nificance of the Frankfurt- mandibular plane angle (FMA) to prosthodontic diagnosis, treatment planning and prognosis in class II malocclusions has been well documented.

Results: Z-angle and Frankfort mandibular incisor plane angle (FMIA) decreased significantly (p < 0.001) with the increase of the skeletal vertical dimension. Incisor mandibular plane angle (IMPA) was significantly higher (p < 0.001) in low-angle patients compared to the high-angle ones.

Frankfort-mandibular plane angle (FMA) and sella-nasion (SN) to mandibular plane angle are often used to describe these three facial patterns in orthodontics ( Figures 5 and 6).

2. Frankfort mandibular plane angle (FMA): The Frankfort mandibular plane angle is formed by Frankfort plane (Po- Or) and the mandibular plane drawn along the lower border of the mandible. Its mean value is 25° (16°-35°) [3]. (Figure 2) ~

Jun 4, 2020 · Aims and objectives: The purpose of this study was to evaluate the linear and angular position of mandibular incisors over the basal bone and their relationship with frankfort mandibular plane angle in different skeletal classes.

The FMA is an angle formed by the intersection of the Frankfort horizontal plane and the mandibular plane. The significance of the FMA to prosthodontic diagnosis, treatment planning and prognosis has been well documented.