PRIME Journal Vol. 12 Issue 1

average, the prognathic profile is more acceptable in men, whereas the retrognathic is preferable in women 5 . Rickett’s E-line (a line between the nose tip to the pogonion) assesses the overall alignment of the nose, lip, and chin. The Rickett’s E-line serves as a reference for the protrusion of the lips and should fall 4 and 2mm from the upper and lower lips, respectively. This line is necessary to identify a malpositioned chin 1 . Besides that, the true vertical line (TVL) is also important to analyze the chin position in the profile. This TLV is a vertical line dropped to the subnasal point and perpendicular to the Frankfort horizontal plane (FH). The TLV is used to verify the chin positionconcerning thepogonionpoint and itsprojection of the TLV 6 . A straightforward way to diagnose micrognathia is to evaluate the measurements of the mandibular arch with the maxillary arch, while if diagnosing retrognathia, one needs to look to evaluate the alveolar overjet. Both micrognathia and retrognathia involve abnormal, arrested development of the mandible. Although it is difficult to distinguish between these conditions, micrognathia refers to the size of the mandible, whereas retrognathia refers to the posterior mandibular positioning in relation to the maxilla 7 . The Jaw Index can be used to identify micrognathia and it is defined by = Aleveolar overjet x (Maxillary arch/Mandibular arch) in millimetres. The Jaw index measures the maxillary- mandibular discrepancy by quantifying the micrognathic and retrognathic jaw through its alveolar relationship with the maxillary development 7 . In general, the mental index (MI) is higher in men than in women; it is measured by the superior border of the foramen mental and the lower mandibular border. In men, the mean of MI was 3.50, while in women, it was 2.96 8 . It is crucial to identify skeletal abnormalities in the chin as well as soft tissue characteristics. A system of chin deformities classification was developed by Guyuron and included 1 : ■ Class I: macrogenia—horizontal, vertical, or a combination of both ■ Class II: microgenia—horizontal, vertical, or a combination of both ■ Class III: combined—horizontal macrogenia with vertical microgenia or horizontal microgenia with vertical macrogenia ■ Class IV: asymmetric chin ■ Class V: chin-soft tissue ptosis ■ Class VI: pseudomacrogenia (normal bony volume with excessive soft tissue) Figure 1 Female patient; the ideal width of the chin is the intercanthal distance, the chin area is more pointed compared with male patient. Figure 2 Male patient; the chin is squarer compared with the female and the ideal width of the chin is the width of the mouth The lower face inmen is, in general, marked by a sharper andmore defined jawline and awider and larger chin area. The female chin ismore pointed and rounded. AESTHETIC FEATURE | INJECTABLES | 18 January/February 2022 |