Soft Tissue Esthetic Changes Following a Modified Twin Block Appliance Therapy: A Prospective Study

Abstract

Aim: Achieving a satisfactory facial esthetics is of utmost importance in the practice of orthodontics. Cl II div 1 patients often suffer from numerous adverse facial characteristics which may impair their social well-being. The objective of the current study was to evaluate the esthetic changes in such patients by using a modified twin block appliance.

Materials and methods: Seventy adolescent patients with mandibular deficiency consecutively underwent treatment with a modified twin block appliance for a mean period of 13 months. Soft tissue analyzes of Burstone and Mcnamara were applied to evaluate the changes before and after the treatment. The esthetic changes before and after the therapy were compared using parametric paired t tests analysis. p values less than 0.05 were considered significant.

Results: Facial convexity, lip incompetence, upper lip protrusion, and columellar inclination significantly decreased (p < 0.05) while Merrifield's Z-angle nasolabial angle, lower lip length, and mentolabial angle significantly increased (p < 0.05). Vertical facial height ratio, lower lip protrusion, upper lip length as well as nasal projection and inclination, did not change significantly (p > 0.05).

Conclusion: Our findings indicated that a modified form of the twin block appliance can be substantially effective in the improvement of several aspects of patients' facial balance with minimum untoward effects.

Clinical significance: Adolescents suffering from mandibular deficiency can gain substantial facial balance with the twin block appliance. The whole face attractiveness, however, is another subject and should not be conflicted with the facial balance.

How to cite this article: Shahamfar M, Atashi MHA, Azima N. Soft Tissue Esthetic Changes Following a Modified Twin Block Appliance Therapy: A Prospective Study. Int J Clin Pediatr Dent 2020;13(3):255-260.

Keywords: Esthetics; Facial profile; Soft tissue; Twin block.

Fig. 1

Design of the appliance

Figs 2A and B

Silhouette of a patient. (A) Pretreatment; (B) Posttreatment

Fig. 3

Landmarks used in the study. G, Glabella; N′, soft tissue nasion; Pn, Pronasale; Sn, subnasale; Ss, sulcus superior; Ls, labrale superior; Sts, stomion superior; Sti, stomion inferior; Li, labrale inferior; Si, sulcus inferior; pog’, Soft tissue pog; Me’, Soft tissue menton; C, cervical point

Fig. 4

Linear measurements used in the study. 1, lower face protrusion; 2, midface protrusion; 3, vertical height ratio, 4, upper lip length; 5, lower lip length; 6, superior labial sulcus depth; 7, inferior labial sulcus depth; 8, upper lip protrusion; 9, lower lip protrusion; 10, interlabial gap; 11, Nasal projection

Fig. 5

Angular measurements used in the study. 1, facial convexity angle; 2, Nasolabial angle; 3, lower face-throat angle; 4, Merrifield's Z-angle; 5, Mentolabial angle; 6, columellar inclination; 7 = inclination of nose