Condyle‐glenoid fossa relationship after Herbst appliance treatment during two stages of craniofacial skeletal maturation: A retrospective study

Abstract

Objectives To perform a three‐dimensional evaluation of the position of the condyles in patients treated with Herbst appliance (HA) in two stages of cervical vertebral maturation. Setting and sample population Retrospective case‐control study. Pubertal Herbst group (PHG; n = 24, mean age 14.5 years, CS 3 and CS 4) and pre‐pubertal Herbst group (PPHG; n = 17, mean age 9.9 years, CS 1 and CS 2) were contrasted with comparison groups of non‐orthopaedically treated Class II patients in pubertal (PCG; n = 17, mean age 13.9 years) and pre‐pubertal maturational stages (PPCG; n = 18, mean age 10.6 years). Materials and Methods Cone‐beam computer tomography scans were taken before treatment (T0) and at T1 after 8 to 12 months. Point‐to‐point measurements of the displacement of the condyles between T0 and T1, relative to the glenoid fossae, were performed in the X, Y, Z and 3D perspectives. Qualitative assessments using semi‐transparent overlays and colour mapping also were produced. Results The displacement of the condyles within the glenoid fossae in the treated groups was small (<0.75 mm; P > .05). Relative to the glenoid fossa, condylar position at T1 was similar to T0 in pre‐pubertal and pubertal groups (P > .05). Similar condylar rotations from T0 to T1 were observed in Herbst and comparison groups, and no significant difference was found between pre‐pubertal and pubertal patients. Conclusions Regardless the stage of skeletal maturation, HA treatment did not change the condyle‐glenoid fossa relationship.

Three-Dimensional Evaluation of Condyle-Glenoid Fossa Complex Following Treatment with Herbst Appliance

“…CBCT has not been frequently used in the evaluation of condylar response to functional orthopaedic therapy in patients with skeletal Class II malocclusion [ 23 , 24 ]. However, only recently, CBCT was used for the 3D assessment of mandibular and glenoid fossa changes [ 13 , 14 , 25 , 26 ]. It has been demonstrated that CBCT provides accurate and reliable linear measurement of the TMJ dimensions of dry human skulls.…”

“…Voudoris et al, have shown condylar anterior condylar displacement following Herbst therapy is stabilized by addition of new bone in posterior aspect of fossa and increased fibrous tissue mass in the posterior aspect of disk [ 35 , 36 ]. The spatial orientation of condyle relatively remains unaffected within the fossa due to minor bone remodelling changes as well as the mechanical drift of condyle into its original position due to soft tissues traction [ 13 , 15 ].…”

“…Condylar positional changes within the fossa have also been proposed but have not been significantly confirmed in either animal or human studies. Recent 3D studies on Herbst therapy have widened the scope of evaluating positional changes of condyle [ 11 , 13 , 14 ]. Further, several methodological flaws still exist, recommending additional 3D investigations for a thorough understanding of the effect of functional appliances on TMJ [ 15 ].…”

The Effect of Functional Mandibular Advancement for Adolecent Patients with Skeletal Class Ⅱ Malocclusion on the TMJ——a Systematic Review and Meta-Analysis

“…Most of researches showed that after treatment, position of the condyle was more forward and glenoid fossa also remodelled, even in the patients who have anterior disc displacement with reduction [27], treatment-induced deterioration was not found in the disc-condyle relationship compared with pre-treatment, while the relationship was improved in some cases.The research published by Payam Owtad et al [28] found that mandibular advancement can increase FGF8 factor in the TMJ area, which can promote adaptive remodeling of the TMJ disc, but it will cost a relatively long time. Published researches had also reported some biomedical effects of functional mandibular advancement devices on the TMJ, the condyle was migrated to a more anterior position, no considerable stress was investigated on the TMJ structure [9,17,28,29], since TMJ discomfort after MADs wearing might be related to muscle dysfunction rather than pressure on TMJ itself [30,31]. Many researchers also found that adolecence appeared active reconstruction in TMJ area [32,33].…”

“…Four of all included studies used MRI to evaluate the morphology and disc-condyle relationship, many researchers [34,35] found patients who received such treatment were more likely to have their temporomandibular joint disc at a more forward position. Paula Loureiro Cheib et al's research [30] indicated that immediately after functional appliance, no signi cant clockwise mandible rotation was observed, on the contrary, the condyles were displaced anteriorly and inferiorly. The systematic review published by Kurt Popowich [17] also supported for the view above that although few patients had their TMJ disc position changed, such changes might cause TMJ discomfort momentarily, but after a period for TMJ to adapt, subjective symptoms and clinical signs seemed to disappear, and no obvious dysfunction was observed in TMJ.…”