Malocclusion Parameter 1st Primary Rugae 2nd Primary Rugae 3rd Primary Rugae
  Right Left Right Left Right Left
Class I Pattern (c) (fd2) (c) (c) (c) (c)
Orientation (h) (h) (a) (p) (a) (p)
Strength (s) (s) (m) (m) (w) (w)
Class II div 1 Pattern (c) (c) (c) (c) (c) (c)
Orientation (p) (p) (a) (p) (a) (a)
Strength (s) (s) (m) (m) (m) (m)
Class II div 2 Pattern (c) (c) (c) (c) (c) (c)
Orientation (h) (p) (h) (h) (h) (h)
Strength (s) (s) (m) (m) (m) (m)
Class III Pattern (c) (fd1) (c) (c) (c) (c)
Orientation (h) (p) (a) (p) (h) (h)
Strength (s) (s) (m) (m) (w) (w)
Table 2: Most common pattern, orientation and strength of primary palatal rugae in various malocclusion groups. Pattern: (c): Curved; (s): straight; (w): wavy; (fd1): forkingconverging; (fd2): forking- diverging; (i): island; (Ir): irregular Orientation: (h): horizontal; (a): anteriorly; (p): Posteriorly Strength; (s): strong; (m): medium; (w): weak.