compensation for mandibular retrognathism by conventional orthodontic and facial orthopedic treatment incurs the risk of ( a ) increase in nasolabial angle , ( b ) reduction in upper lip support , ( c ) increase in lower facial concavity , ( d ) excessive proclination of lower incisors with compromise of labial periodontal support , and ( e ) protracted duration of appliance therapy and accompanying detrimental periodontal and root resorption effects .
C0226936
upper lip
C0023759
labial