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Results for “Activator Appliances”

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At least 19 recordsLinked to original sources
PubMed2003

The effect of mandibular protrusive (activator) appliances on articular eminence morphology.

In studying the response of the glenoid fossa to mandibular protrusive appliances, apart from the condyle, much attention has been focused on what happens to the posterior wall of the fossa (post-glenoid process). Remarkably, the articular eminence has been overlooked, although it is the most adaptive area of the temporomandibular joint. The purpose of this study was to explore the type of response of the articular eminence morphology to the use of mandibular propulsive appliances (activators). The study material consisted of individually corrected pre- and posttreatment lateral tomograms of 35 patients (18 boys and 17 girls) who had been diagnosed as suitable for treatment with a mandibular protrusive appliance (activator). The tomograms were scanned and digitized on screen, and points located on each tomogram and linear measurements were used to evaluate any change in glenoid fossa morphology. Paired t-tests were applied separately for the left and right sides to compare pre- and posttreatment measurements. Paired t-tests were also applied to test any difference between the left and right sides. The results of this study show that there is no statistically significant change in articular eminence morphology (height and inclination) as a result of using mandibular protrusive appliances.

Activator Appliances↗
PubMed1985

A lip-activated appliance in early orthodontic treatment.

After reviewing the modes of action and types of lip-activated appliances, three cases were reported. A mandibular lip-activated appliance was used to gain space among the incisors and mesial to the mandibular permanent first molars; a maxillary lip-activated appliance was used to correct an anterior crossbite by labial movement of the incisors; and a modified lip-activated appliance was used to expand maxillary molars buccally.

Activator Appliances↗
PubMed1992

[Elastic activator appliances: Bimler's elastic appliance and Klammt's elastic activator].

The action of two elastic activators (Bimler and Klammt) is studied in twenty Class II/1 malocclusions, with a mean age of 10.2 years and a treatment time of 2.7 years. Intercanine and intermolar widths, and "anterior arch height" (Korkhaus) were measured on models at the beginning and at the end of treatment. On lateral X-Ray films following parameters (Ricketts) were measured: facial axis, facial depth, convexity, lower facial height, and corpus axis. Conclusions are: both appliances have a good transverse response, Bimler's Gebissformer increase vertical growth, and Klammt's elastic activator decrease convexity by a more anterior mandibular positioning.

Activator Appliances↗
PubMed1991

[Biomechanical aspects of the spring-active-appliance during the night sleep].

1. During the night the mandibular activities caused by the spring-active-appliance are increased. Seven times more mandibular movements occur compared to the activator according to Andresen-Häupl. 2. A distinct increased mandibular activity during the time the patient fall asleep or in the wake up time can be registered, especially in the adaptation phase or after reactivating the springs. 3. Powerful activities of the m. masseter did not lead to an inversion of the mandibular movement. 4. A regular movement of the mandible is the most frequent movement whilst mandibular activities. 5. During the night asymmetrical activities of the mm. masseters very often occur. 6. An inversion of the mandibular movement, that means a counter-clockwise-rotation of the m. mandible, occurs if the force direction of the m. temporalis is directed more distally or if the ratio between masseter- and temporalis activities are for the benefit of the temporalis-activities. 7. During the night the springs in the spring-active-appliance cause a counter-clock wise-rotation of the mandible without mandibular activities around a transverse axis in the region of the molars. This leads to an approach of the anterior teeth whilst the distance between the molars remains constant. 8. Contrary movements and rotations around a transverse axis in the region of the molars lead to a distraction of the condyle of about one millimeter.

Activator Appliances↗
PubMed2002

Growth and treatment changes in patients treated with a headgear-activator appliance.

The aim of this study was to investigate growth and treatment changes in patients with Class II Division 1 malocclusion treated with a combined headgear-activator appliance. The sample consisted of 20 consecutive male patients treated with headgear-activator. Their compliance was checked after 2 months of treatment, and 3 patients dropped out. Lateral cephalograms, obtained 6 months before treatment, at the start of treatment, after 6 and 12 months of treatment, and 24 months after treatment, were analyzed by the method of Pancherz. The results disclosed that during growth, on average, overjet, molar relationship, and jaw-base relationship improved, and the mandibular incisors became retruded; the changes were statistically significant over a 2-year period. There was no significant change in the overbite. During the 12 months of treatment, there was no maxillary forward growth, and the jaw relationship improved (P <.001) because of forward growth of the mandible (P <.001). The molar relationship and the overbite improved (P <.001). Significant treatment effects included reduction in overjet (P <.001) and overbite (P <.01), and improvement of jaw-base (P <.05) and molar (P <.001) relationships. There was significant restraint of maxillary forward growth (P <.05). The eruption of the maxillary incisors and molars was restrained (P <.05). The average basic growth pattern in Class II Division 1 malocclusion resulted in small favorable changes in overjet, molar relationship, and jaw-base relationship. The main effect of the headgear-activator appliance was a favorable dental change, limited to restraint of maxillary forward growth but not affecting the vertical dimension.

Activator Appliances↗
PubMed1997

Use of activator appliances in pediatric patients treated with costochondral grafts for temporomandibular joint ankylosis: analysis of 13 cases.

PURPOSE: The long-term outcomes and clinical results of costochondral transplants used for the treatment of condylar ankylosis of the mandible in children with and without application of postoperative activator appliances are evaluated and compared. MATERIALS AND METHODS: A nonrandomized, retrospective clinical study of 13 cases of condylar ankylosis (16 joints) of the mandible surgically treated during a 9-year period from 1988 to 1997 was performed. All 13 patients were treated by condylectomy and immediate costochondral rib grafts. Nine of these patients underwent long-term postoperative therapy using removable activator appliances. Four patients did not undergo activator therapy postoperatively. Casts, radiographs, photographs, computed tomography (CT) scans, magnetic resonance imaging (MRI) and 99Tc bone scans were used postsurgically to evaluate graft take, condylar growth and function, occlusion, and facial and condylar symmetry. RESULTS: The postoperative and long-term clinical results in both groups showed costochondral growth center transplants to be effective in restoring mandibular growth of the affected side. However, symmetry, arch coordination, correction of occlusal canting, mandibular deviation, facial growth, and prevention of reankylosis were obtained and better controlled only in those cases that underwent long-term orthodontic activator therapy postoperatively and were followed closely. CONCLUSIONS: Children with long-standing condylar ankylosis of the mandible and its resultant facial asymmetry and occlusal canting (secondary to a nonfunctional joint and maxillary compensation) treated with condylectomy and immediate costochondral rib graft reconstruction of the affected joint were treated more favorably when activators were used postsurgically. The patients that failed to comply with or continue activator therapy postsurgically developed complications relating to mandibular deviation, occlusal dysharmony, asymmetry and, in one case, reankylosis of the temporomandibular joint (TMJ).

Activator Appliances↗
PubMed1989

Facial changes in children treated with the Activator appliance: a lateral cephalometric study.

Using lateral cephalometry, facial profile changes in 32 children treated with the Activator appliance were assessed and compared to profile changes in 12 untreated children of same age and with similar malocclusions. The results of this study indicated that the maxillary region of the facial profile underwent similar changes in both groups. In contrast, the mandibular changes were different, with the treated group showing more mandibular advancement than the untreated group during the period examined.

Activator Appliances↗
PubMed1982

Changes in length and torque of the masticatory muscles produced by the activator appliance. A cephalometric study.

The purpose of this study was to measure cephalometrically the change in muscle length and torque of the masticatory muscles produced by an activator appliance. The study was based on 10 orthodontic cases with distoclusion. Muscle length and force arm (leverage) were measured on two lateral cephalometric roentgenograms of each subject, one with the teeth in centric occlusion and one with an activator between the teeth. The construction bite of the activator was taken with the mandible repositioned 2-3 mm below and 5-6 mm ahead of resting position. It was found that the temporal masseter and medial pterygoid muscles increased 5-15% in length whereas the lateral pterygoid decreased 25% in length with the activator in place. The effect on the force arm on the temporal muscle was small, a decrease of 3-6%, but that on the masseter was much more dramatic, a decrease of 21-22%. Thus, as far as the torque of the temporal muscle is concerned, the small decrease in force arm is well compensated for by the increased muscle tension due to the stretching by the activator. The clinical significance of the findings for obtaining the best construction bite of the activator is discussed.

Activator Appliances↗
PubMed2002

Study of occlusal-maxillo-facial 3-dimentional structural change of orthodontic therapy of crossbite malocclusion by modified ACTIVATOR appliance.

Occlusal-maxillo-facial structural change of crossbite malocclusion after orthodontic therapy by modified ACTIVATOR appliance was investigated. Eighty crossbite cases of deciduous dentition and mixed dentition were treated by modified ACTIVATOR. Through pre- and post-treatment analysis of stone model, Schuller's position X-ray and craniofaciometrics, the change in craniofacial length, width and height in early-phase crossbite malocclusion was studied. The results showed that there was no significant change in the width of maxillary and mandibular dental arch. Maxillary length and protrusion was increased significantly, upper incisors slopped labially. The lower incisors slopped lingually, mental angle decreased more severely. The lower and posterior facial height was increased to normal level.

Cephalometry↗
PubMed2005

Matrix metalloproteinase-1 and -8 in gingival crevicular fluid during orthodontic tooth movement: a pilot study during 1 month of follow-up after fixed appliance activation.

The role of matrix metalloproteinases (MMPs) in response to mechanical forces in orthodontic tooth movement has only been partially clarified. In the present in vivo pilot study, the presence, levels, and degree of activation of MMP-1 and -8 were measured daily for 1 month in gingival crevicular fluid (GCF) of patients treated with orthodontic fixed appliances. GCF samples were collected from five orthodontic patients and three controls from one upper or lower central incisor or from one upper canine before fixed appliance activation and every 24 hours for 1 month thereafter. The molecular forms and activation degrees of MMP-1 and -8 in GCF were analysed by Western blotting, and MMP-8 levels determined by immunofluorometric assay (IFMA).IFMA revealed, during the study period, on average 12-fold higher levels (56 +/- 50 versus 4.6 +/- 4 microg/l) of MMP-8 in orthodontic GCF than in control GCF. The MMP-8 levels in orthodontic GCF were lower than those detected in gingivitis and periodontitis GCF, but significantly higher than in control GCF. IFMA analysis was confirmed by Western blot analysis showing elevated MMP-8 levels from orthodontic GCF relative to control GCF. Forty-one per cent of total MMP-8 immunoreactivities were high-molecular weight complexes (>100 kDa), 32 per cent in the 75 kDa pro-polymorphonuclear (PMN)-MMP-8 form, 14 per cent in the 60 kDa active-PMN-MMP-8 form, and 13 per cent in the 55 kDa fibroblast-type pro-MMP-8 form. In the GCF of orthodontic patients no MMP-1 immunoreactivities were detected. MMP-8 and -1 levels in the control GCF were low and not detectable. These results demonstrate that in vivo in human GCF, elevation and partial activation of multiple species of PMN- and fibroblast-type MMP-8 reflect periodontal remodelling during orthodontic tooth movement.

Adolescent↗