SOFT-TISSUE LIMITATIONS IN ORTHODONTICS - TREATMENT PLANNING GUIDELINES

Orthodontists have traditionally viewed structural discrepancies as th e major limitation of treatment. In reality, it is the soft tissues th at more closely determine therapeutic modifiability. The boundaries of dental compensation for an underlying jaw discrepancy are established by pressures exerted on the teeth by the lips, cheeks, and tongue; li mitations of the periodontal attachment; neuromuscular influences on m andibular position; and the contours of the soft tissue facial mask. T he ability of the soft tissues to adapt to changes in tooth-jaw relati onships are far narrower than the anatomic limits in correcting occlus al relationships. The tolerances for soft tissue adaptation from equil ibrium, periodontal, and facial balance standpoints are in the range o f 2 to 3 mm for expansion of the mandibular arch and even less for cha nges in condylar position. Thus, analysis of the soft tissues is the c ritical step in orthodontic decision making, and this can only be acco mplished through physical examination of the patient. Although quantit ative measurements cannot be rigorously applied, guidelines for soft t issue assessment, with particular emphasis on facial esthetics, are pr oposed. From this perspective, a contemporary philosophy of orthodonti c practice is offered, with general indications and contraindications for nonextraction, extraction, and surgical treatment.