Retrospective 25-year follow-up of treatment outcomes in Angle Class III patients

Abstract

ObjectivesDespite recommendations for early treatment of hereditary Angle Class III syndrome, late pubertal growth may cause a relapse requiring surgical intervention. This study was performed to identify predictors of successful Class III treatment.Materials and methodsThirty-eight Class III patients treated with a chincup were retrospectively analyzed. Data were collected from the data archive, cephalograms, and casts, including pretreatment (T0) and posttreatment (T1) data, as well as long-term follow-up data collected approximately 25 years after treatment (T2). Each patient was assigned to a success or a failure group. Data were analyzed based on time (T0, T1, T2), deviations from normal (Class I), and prognathism types (true mandibular prognathism, maxillary retrognathism, combined pro- and retrognathism).ResultsCompared to Class I normal values, the data obtained in both groups yielded 11 significant parameters. The success group showed values closer to normal at all times (T0, T1, T2) and vertical parameters decreased from T0 to T2. The failure group showed higher values for vertical and horizontal mandibular growth, as well as dentally more protrusion of the lower anterior teeth and more negative overjet at all times. In adittion, total gonial and upper gonial angle were higher at T0 and T1. A prognostic score—yet to be evaluated in clinical practice—was developed from the results. The failure group showed greater amounts of horizontal development during the years between T1 and T2. Treatment of true mandibular prognathism achieved better outcomes in female patients. Cases of maxillary retrognathism were treated very successfully without gender difference. Failure was clearly more prevalent, again without gender difference, among the patients with combined mandibular prognathism and maxillary retrognathism. Crossbite situations were observed in 44% of cases at T0. Even though this finding had been resolved by T1, it relapsed in 16% of the cases by T2.ConclusionThe failure rate increased in cases of combined mandibular prognathism and maxillary retrognathism. Precisely in these combined Class III situations, it should be useful to apply the diagnostic and prognostic parameters identified in the present study and to provide the patients with specific information about the increased risk of failure.

Stability prediction of early orthopedic treatment in Class III malocclusion: morphologic discriminant analysis

“…As observed by Lee [33], arches' size and shape have considerable implications in orthodontic diagnosis and treatment planning, as they affect available space, dental relationship, and stability. In literature, however, few works investigated predictive variables class III early orthopedic treatment failure on dental arches morphology [21,22].…”

“…These patients were seen every 6 months until they reached a skeletal cervical maturation CS4 with all their permanent teeth erupted except for the third molars (mean age 14.5 years ± 5 months). Before starting the second phase of treatment (T1), radiographs and dental casts were acquired to assess orthopedic treatment stability, checking molar, and canine dental class, as reported by Wendl et al [22], sagittal and vertical skeletal relationship on lateral cephalograms and esthetic characteristics of patient's profile [20].…”

“…Since then, many authors investigated prognostic factors useful as predictive stability variables, but their works generally focused on cephalometric analysis. The predictive stability variables most frequently observed are as follows: gonial angle, Wits appraisal, ramus length, lower incisors inclination relative to mandibular plane, mandibular plane angle, SNB angle, and CondAx-SBL [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24].…”

“…In 1997, Franchi et al [21] evaluated three linear transversal measurements (maxillary and mandibular deciduous intermolar width, transverse discrepancy) in 45 dental casts of patients with class III malocclusion in deciduous dentition, and they found that mandibular transverse width was a relapse predictor. Twenty years later, in 2017, Wendl et al [22] examined the differences between successful and unsuccessful treated class III malocclusion patients on dental casts and found out that a narrower maxillary intermolar width could be an additional risk to relapse.…”

Novel Sub-Clustering of Class III Skeletal Malocclusion Phenotypes in a Southern European Population Based on Proportional Measurements

“…Skeletal Class III malocclusions are among the most challenging malocclusions to treat, first because of the complexity of achieving an optimal treatment outcome [ 1 , 2 , 3 ] and second, because the clear genetic component determines the prognosis of this type of malocclusion [ 4 , 5 , 6 , 7 , 8 , 9 ]. Distinguishable ethnic differences have been described in this type of malocclusion, with prevalences ranging from 4.76% [ 10 ] to 31.4% [ 11 ] in Asian populations to rates below 11% in countries such as Australia (2.5%) [ 12 ] Italy (4.3%) [ 13 ], Colombia (5.8%) [ 14 ], South India (4.1%) [ 15 ], Iran (7.8%) [ 16 ], and Central Turkey (10.3%) [ 17 ].…”