Remodeling Of Glenoid Fossa Research Articles

Three-dimensional bone remodelling of glenoid fossa in patients with skeletal Class III malocclusion after bimaxillary orthognathic surgery

This study aimed to characterize three-dimensional quantitative morphological changes of glenoid fossa in patients with skeletal Class III malocclusion treated with bimaxillary orthognathic surgery. Ninety-five eligible patients (50 male, 45 female; mean age 22.09 years) were enrolled retrospectively. Cone beam computed tomography obtained at 1 week preoperatively (T0), immediately after surgery (T1), and at ≥ 12 months postoperatively (T2) were registered based on cranial base using voxel-based registration in 3D Slicer. Glenoid fossa surface was divided spatially into four regions, and bone modelling in these regions was visualized with color maps. Our data revealed that the mean surface variations of glenoid fossa were small, with modest bone formation as a whole. No significant associations between anteroposterior or vertical mandibular displacement and overall glenoid fossa remodeling were found (P > 0.05). Moreover, bone deposition was frequently observed in the anterior-lateral region of glenoid fossa in patients with a larger mandibular movement during T0–T1 (P < 0.001). Paired bone formation in the anterior-lateral region of glenoid fossa and bone resorption in the anterior-lateral region of condylar head was frequently observed. Collectively, our results revealed that glenoid fossa underwent complex but modest bone remodeling after bimaxillary surgery in skeletal Class III patients.

Investigating the relationship between the remodeling of TMJ bony structures and condylar rest position following orthognathic surgery in class II and class III skeletal malocclusions

ObjectivesWe investigated the bone remodeling in the condyle and glenoid fossa after surgically corrected class II and class III dentoskeletal malocclusion patients and the relationship between these changes and the condylar rest position. MethodsA retrospective study was conducted based on the pre-operative and 1-year postoperative computed tomography (CT) scans of class II and class III skeletal malocclusion patients. Condylar remodeling was assessed by total volume change and surface distance between corresponding points in the regions of interest (ROI). Glenoid fossa remodeling was measured by the surface distance between the closest points in the ROI. The association between the remodeling of TMJ bony structures and the condylar position was tested by Spearman’s correlation. ResultsTwenty-one subjects with class II (17 females, 4 males) and twenty subjects with class III (13 females, 7 males) were recruited.The condylar volumes significantly decreased after surgery in class II malocclusion patients and significantly increased in class III malocclusion patients (p < 0.01). The condyle and glenoid fossa experienced remodeling of less than 1.5 mm and 1 mm respectively. Positional change of condyle at the jaw rest position had a weak correlation with condylar remodeling (p < 0.05, 0.2 ≤ |r| ≤0.4), but no association with the glenoid fossa remodeling (p > 0.05). ConclusionsThe volume of condyles changed significantly after orthognathic surgery in both groups. Both condyle and glenoid fossa experienced remodeling in class II and Class III patients. Those changes did not considerably influence the change of the condylar rest position.

Effect of stabilization splint therapy on glenoid fossa remodeling in temporomandibular joint osteoarthritis

PurposeThe aim of this study was to evaluate, by CBCT superimposition, bone changes (cortical bone intactness, sclerosis and subchondral cyst) in the glenoid fossa related to stabilization splint (SS) therapy for temporomandibular joint osteoarthritis (TMJ OA) patients and to compare the effects for two groups, one that had undergone SS therapy and the other that had not. MethodsThis case–control study included 36 TMJ OA patients, 10 that had undergone SS therapy (the SS group) compared with 26 that had not (the non-SS group). Osseous changes in the glenoid fossa were evaluated based on superimposed CBCT images before and after treatment. ResultsImprovements ranging from 57.5 to 100% were achieved in cortical bone integrity, sclerosis, and subchondral cyst for both groups, SS and non-SS. However, there were no statistically significant difference between the two groups (p>0.05). The non-SS group showed a significant decrease in the distances from the point of inflexion and the lowest point of the articular eminence to the reference line (p<0.05). On the other hand, the SS group showed an increase for the point of inflexion. The other measures showed no statistically significant differences in distance before treatment and after treatment, even though the average distance after treatment showed an overall increasing tendency. ConclusionSS therapy relieved excessive loading on the TMJ in the TMD OA patients, who showed, via CBCT superimposition, less bone resorption in the glenoid fossa.

Role of the horizontal activator in Class II i malocclusion treatment.

Background: The conflict in opinions about the dental and skeletal changes induced by class II malocclusion activator therapy is still present. The aim of this study was to assess the skeletal and/or dental outcomes of treating moderate-severe skeletal class II division 1 malocclusion by the activator. Materials and Methods: The sample consisted of pre and post treatment records (cephalometric radiographs) of 11 Iraqi adolescent patients (7 females 10-11 years old, and 4 males 12-13 years old). Results: The results showed significant skeletal and dental changes that reflected significant improvements in the cardinal features of class II (overjet, overbite, ANB angle, and lower anterior facial height). Conclusion: Correction of the overjet, overbite, and ANB angle in moderate-severe skeletal class II i cases by the activator into normal range values may be at the expense of unfavorable lower incisors proclination and ii angle which are very important for stability of treatment result. The activator can induce skeletal changes that reflect improvements in the antero-posterior and vertical relationships of class II i malocclusion (downward and forward growth of the mandible, remodeling of glenoid fossa, in addition to the rotation of maxillary and mandibular bases). Acrylic loading and acrylic trimming done in the activator are responsible for the dramatic dental changes that can sometimes contribute to the skeletal improvements (extrusion of lower posterior teeth, relative intrusion of incisors, overjet and overbite correction, and changing positions of points A and B).

Effect of Herbst treatment on temporomandibular joint morphology: A systematic literature review

The purpose of this systematic review was to evaluate the effect of Herbst appliance therapy on temporomandibular joint (TMJ) morphology, with special reference to glenoid fossa remodeling, condylar remodeling, condylar position, and articular disc position. Publications of controlled trials of Herbst treatment of Class II patients using magnetic resonance imaging (MRI), computerized tomography scans, or tomography to assess TMJ morphology were identified with Medline (1966-2001), Best Evidence (1991-2001), Cochrane Database of Systematic Reviews (second quarter, 2001), and Embase (1998-2001). Case reports were excluded. Based on our search, only 5 studies met the selection criteria. All studies used internal controls with pretreatment and posttreatment imaging. Four studies used MRI, and 1 used tomograms. The 4 MRI studies used overlapping patient samples and were not considered as independent evidence. The MRI studies did not provide conclusive evidence of osseous remodeling or condyle position change. The tomography study demonstrated minor condyle position change. Methodological deficiencies prevented major conclusions regarding disc position. The reviewed studies highlight the importance of further research. Prospective controlled studies using serial MRI and tomography are required to establish the effect of Herbst treatment on TMJ morphology. (Am J Orthod Dentofacial Orthop 2003;123:388-94)

Effective condylar growth and chin position changes in activator treatment: a cephalometric roentgenographic study.

Effective condylar growth (a summation of condylar remodeling, glenoid fossa remodeling, and condylar position changes within the fossa) and its influence on the position of the chin was analyzed in 40 class II, division I malocclusions treated successfully with activators. Additionally, the amount of mandibular rotation was assessed. Lateral head films in habitual occlusion from before and after an average treatment period of 2.6 years were evaluated. The Bolton Standards (32 untreated individuals with ideal occlusion) served as controls. Two different treatment effects were evaluated: overall growth change and treatment effects (overall growth changes minus age-related Bolton values). In comparison with the Bolton group, the activator patients exhibited an increase in the amount of vertical effective condylar growth (3.0 mm; P < .001), a decrease in the amount of sagittal effective condylar growth (0.6 mm; P < .05), and an increase in the amount of vertical development of the chin (1.8 mm; P < .001). No group differences could be found for sagittal development of the chin. In the Bolton group, the mandible rotated posteriorly, and in the activator group it rotated anteriorly (2.7 degrees; P < .001). The present investigation revealed that effective condylar growth can be increased and the chin position can be changed by activator treatment. Thus activator treatment induces skeletal changes, although not always in the desired (sagittal) therapeutic direction.

Does 2 years’ nocturnal treatment with a mandibular advancement splint in adult patients with snoring and OSAS cause a change in the posture of the mandible?

The aim of this pilot study was to investigate the effects of 2 years’ nocturnal treatment with a mandibular advancement splint in adult patients with snoring and obstructive sleep apnea syndrome with respect to possible development of a forward position of the mandible or other dentofacial changes. Thirty snoring and sleep apnea patients, mean age 55.3 years (SD, 8.61; range, 46.5 to 79.8 years), referred from the Ear, Nose, and Throat Department, were treated with an acrylic splint with full tooth coverage that advanced the mandible 5 to 8 mm (70% of maximal protrusion) and used 5 mm opening vertically. The splint was used 6 to 8 hours per night and 5 to 7 nights per week. Two lateral head radiographs were taken in centric occlusion, 1 before and 1 after 2 years of treatment. A small but statistically significant forward and downward change in mandibular position was found after treatment; mean was 0.4 mm (SD, 0.53; range, 0.0 to 2.0 mm; P < .001) and 0.3 mm (SD, 0.43; range, 0.0 to 1.5 mm; P < .001), respectively. The forward and downward movement of the mandible was accomplished by a statistically significant increase in mandibular length—mean was 0.4 mm (SD, 0.62; range, 0.0 to 2.5 mm; P < .01)—and a significant decrease in overjet ( P < .001) and overbite ( P < .05). However, none of the patients reported any permanent sense of altered occlusion, and the anteroposterior distance between habitual occlusion (intercuspal position) and centric relation (retruded position) did not exceed 1.0 mm in any of the patients either before or after the treatment. The change in mandibular position might be a result of a condylar and/or glenoid fossa remodeling or condylar position changes within the fossa as a compensatory reaction to the advancement of the mandible (bite jumping). However, to visualize and analyze such possible changes in detail, additional studies using lateral tomography of the temporomandibular joints or magnetic resonance imaging are required. Furthermore, because the treatment of snoring and OSAS patients is considered to be lifelong, long-term studies are needed to analyze if the small change in mandibular position will continue with further treatment. (Am J Orthod Dentofacial Orthop 1999;116:621-8)

Temporomandibular joint remodeling in adolescents and young adults during Herbst treatment: A prospective longitudinal magnetic resonance imaging and cephalometric radiographic investigation

The aim of this prospective study was to analyze and compare the temporomandibular joint adaptive mechanisms in 25 adolescent and 14 young adult Class II malocclusions treated with the Herbst appliance. Temporomandibular joint remodeling was analyzed by magnetic resonance imaging. In each subject, 4 magnetic resonance images of both temporomandibular joints were available: before treatment, at the start of treatment (when the Herbst appliance was placed), during treatment (6 to 12 weeks after appliance placement), and after treatment (when the appliance was removed). Furthermore, effective temporomandibular joint changes (the sum of condylar remodeling, fossa remodeling, and condyle-fossa relationship changes) were analyzed with the aid of lateral cephalometric radiographs from before and after treatment. All subjects were treated to Class I or overcorrected Class I dental arch relationships, and their mandibles became significantly ( P < .001) more prognathic. After 6 to 12 weeks of Herbst treatment, signs of condylar remodeling were seen at the posterosuperior border in 48 of the 50 adolescent condyles and in 26 of the 28 young adult condyles. Bilateral remodeling of the mandibular ramus could be detected in 1 adolescent and 2 young adult patients. Signs of glenoid fossa remodeling at the anterior surface of the postglenoid spine were noted in 36 adolescent and 22 young adult temporomandibular joints. Effective temporomandibular joint changes during treatment were more horizontally directed and larger in both adolescents and young adult patients treated with the Herbst appliance than in an untreated group of subjects with ideal occlusion (Bolton standards). The increase in mandibular prognathism accomplished by Herbst therapy in both adolescents and young adults seems, in particular, to be a result of condylar and glenoid fossa remodeling. Because the Herbst appliance is most successful in Class II patients also at the end of the growth period, the treatment method could be an alternative to orthognathic surgery in borderline skeletal Class II cases. Magnetic resonance imaging renders an excellent opportunity to visualize the temporomandibular joint remodeling growth processes. (Am J Orthod Dentofacial Orthop 1999;115:607-18)

“Effective condylar growth” and chin position changes in Herbst treatment: A cephalometric roentgenographic long-term study

In 98 Class II Division 1 malocclusions treated with the Herbst appliance “effective condylar growth” (a summation of condylar remodeling, glenoid fossa remodeling, and condylar position changes within the fossa) and its influence on the position of the chin was analyzed. Lateral head films in habitual occlusion from before and after 0.6 years of Herbst treatment as well as 0.6 years and 3.1 years posttreatment were evaluated. All patients were treated to Class I or overcorrected Class I dental arch relationships. During the treatment period, effective condylar growth was relatively more backward directed and about three times larger than that in untreated subjects with ideal occlusion (Bolton Standards). During the first posttreatment period of 0.6 years, effective condylar growth recovered with respect to both the direction and amount of changes. During the second posttreatment period of 2.5 years, effective condylar growth was “normal.” The corresponding chin position changes during the different examination periods were a mirror image of effective condylar growth provided no mandibular autorotation occurred. In cases with anterior mandibular autorotation, relatively more forward and in cases with posterior mandibular autorotation relatively more backward directed chin position changes resulted. (Am J Orthod Dentofacial Orthop 1998;114:437-46)

The influence of functional appliance therapy on glenoid fossa remodeling

This study investigates the remodeling changes in the condyle and glenoid fossa following a period of progressively activated and continuously maintained mandibular advancement using the Herbst appliance. Progressive mandibular advancement was achieved by adding stops to the telescopic arms of the appliance, with the total activation reaching 7.0 to 10.0 mm, dependent upon the length of the treatment phase. This mandibular advancement produced extensive remodeling and anterior relocation of the glenoid fossa, which contributed to anterior mandibular positioning and altered jaw relationships.