Amount Of Mandibular Growth Research Articles

Fixed functional appliances for correction of Class II malocclusion: A review

This review article presents various fixed functional appliances that have been developed all these years with the aim of correcting Class II malocclusion. Class II malocclusion though multifactorial in etiology, but the main cause is mandibular retrognathia. The treatment aims to modify the direction and amount of mandibular growth rather than restricting the development of the maxilla. Hence, the various appliances were developed removable and fixed with the aim to correct Class II malocclusion. Fixed functional appliances were developed with the aim to correct Class II malocclusion without the need of patient compliance, which was a major concern toward removable functional appliances.

Effects of growth hormone and functional appliance on mandibular growth in an adolescent rat model.

To investigate the individual and synergistic effects of growth hormone (GH) and functional appliance (FA) on mandibular growth in an adolescent rat model. Forty adolescent (6-week-old) female Wistar rats were randomly divided into four groups (10 rats in each group). The control group received a sham treatment (intra-abdominal injection of phosphate-buffered saline), the GH group received an intra-abdominal injection of recombinant human growth hormone, the FA group was treated with a mandibular advancement device, and the GH+FA group received both the GH and FA treatments. The amount of mandibular growth in each group was measured quantitatively using cone-bean computed tomography. The growth of condylar cartilage and expression of matrix metalloproteinases-1 and -13 (MMP-1 and MMP-13) and type II and X collagen (Col II and Col X) were assessed using histological staining and immunostaining techniques. After 4 weeks, there was significant mandibular growth in the FA group compared with the control group ( P < .05). The GH+FA group had significantly greater mandibular length, thickness of condylar cartilage, and expression of MMP-1, MMP-13, Col II, and Col X in the cartilage than the other groups ( P < .05). The GH+FA group and GH group had significantly greater weight than the FA and control groups ( P < .05). The FA as well as GH+FA stimulated mandibular growth in adolescent rats.

A change of paradigm in the treatment of Class II malocclusions in children and adolescents: the benefits of the Class II Corrector

The treatment of class II malocclusions is the core of our clinical activity. What elements can clinician rely on to offer their patients, whether children or adolescents, a treatment of their class II malocclusion that is not only effective but also the most appropriate for each individual case? Which schedule and what therapeutic device should be used? Evidence-based orthodontics, along with a search for the best data on two-phase treatments, were used to judge the validity of the main objectives sought when correcting a Class II malocclusion in children or adolescents, including treatment of mandibular retrognathy. Published data show that the long-term effects of a first phase of treatment on the amount of mandibular growth are at best weak and clinically insignificant. This observation triggers a paradigm shift by refocusing patient treatment on the achievement of other therapeutic objectives. A new orthodontic appliance, the Clas II Corrector, is presented. Its advantages and its use are described and illustrated by means of clinical cases. Class II Corrector allows distalization of maxillary lateral areas, effectively limits undesirable dentoalveolar compensations and facilitates the rehabilitation of orofacial functions. In addition to its clinical efficacy, patients appreciate its small footprint, ease of wearing, and lack of impact on phonation.

The search for balance in the therapeutic decision-making process: the example of Class II malocclusion treatments in children and adolescents

Therapeutic decision-making is essentially the key to our clinical practice, and its most medical feature. The history of orthodontics is studded with multiple intellectual debates and stand-offs between conflicting treatment philosophies, the authors of which all aspire to a balance guaranteeing optimal treatment for their patients. Among the wealth of published data, which items should we select to ensure balanced treatment decisions in our daily practice and how can we remain serene in the face of the uncertainty and loneliness engendered by therapeutic decision-making process? Evidence-based orthodontics is an aid to clinical decisionmaking. Its main features are illustrated by four clinical cases describing the treatment of class II malocclusions in children and adolescents. A search for the best pre-evaluated data on two-step treatments shows that : (1) a significant reduction in the prevalence of incisive trauma is observed in children when an increased overjet is corrected by an initial treatment phase, compared to single-stage treatments conducted in early adolescence; (2) the long-term impact of the first treatment phase on the amount of mandibular growth is at best weak and clinically insignificant. The evidence-based approach, particularly when performed in user mode, enables us to reach more balanced clinical decisions. However, the article points out the key role of the clinician and the double risk of reducing the evidence-based approach to a mere standard of care - which it is not - and the subordination of treatment management to the strict clinical application of data in the literature.

Mandibular behavior in the treatment of skeletal Class II malocclusion: a 5-year post-retention analysis

Aim: This study aimed to assess mandibular behavior in Class II subjects subjected to full orthodontic treatment with standard edgewise appliance and cervical headgear (Kloehn appliance) during the pubertal growth spurt period. Methods: Lateral cephalometric radiographs of 40 patients (21 females and 19 males) were performed at the beginning of the treatment (T0 ), at its end (T1 ) and at 5-year post-retention phase (T2 ) in order to quantify the cephalometric measurements (8 angular and 3 linear), representing the mandibular behavior in the anteroposterior and vertical senses. The mean age of female patients at T0 , T1 and T2 was 11.4, 15 and 26 years, respectively, and for male patients it was 12.2, 16.7 and 28 years, respectively. All patients were treated in just one phase without extractions and not associating Class II intermaxillary elastics. Results: The effective treatment of skeletal Class II malocclusion with conventional Edgewise fixed appliance and Kloehn cervical headgear did not interfere in the direction and amount of mandibular growth as well as remodeling at it is inferior border, with no influence in anti-clockwise rotation of the mandible. The mandibular growth was also observed after the orthodontic treatment, suggesting that it is influenced by genetic factors. Conclusion: These observations may lead to the speculation that growing patients with skeletal Class II malocclusion and low mandibular plane are conducive to a good treatment and long-term stability.

Maxillomandibular growth 2 years after mandibular advancement surgery with and without suprahyoid myotomy in juvenile Macaca mulatta

There is conflict in the literature on whether continued and harmonious growth occurs after mandibular advancement in growing persons. The studies available are difficult to interpret because of the differing age ranges and the questionable growth potential inherent within the mandibular deficient patient. This study was performed to isolate the major question of interest to clinicians: Does the mandibular advancement surgical procedure inhibit future growth in a normally growing person? Six juvenile male Macaca mulatta monkeys were divided equally into two experimental groups. Group MAA had mandibular advancement surgery of approximately 4 mm. Group MAD had a similar surgical procedure with detachment of the suprahyoid musculature. All underwent 4 to 5 weeks of maxillomandibular fixation. Serial computerized cephalograms with the aid of bone markers were used to analyze the changes during a 2-year follow-up period. The postsurgical changes of the two experimental groups were compared statistically with control growth data on a large sample of normal Macaca mulatta animals available in our laboratory. The results showed the following. (1) There were significant short-term differences in the stability of the mandibular advancement between experimental groups. Group MAA (suprahyoid musculature attached) experienced significant relapse during the period of maxillomandibular fixation. Group MAD (suprahyoid musculature detached) experienced no relapse. (2) During the 2-year follow-up period after fixation, the rate and amount of mandibular growth in both experimental groups were not significantly different from age-matched controls or from each other. (3) At the end of the 2-year experimental period, the advanced mandibles were longer than the mandibles in age-matched controls. Thus the experimental animals tended to retain the surgically induced increase in mandibular length that was present after the period of maxillomandibular fixation.

The effect of activator treatment on Class II malocclusions

It was the purpose of this investigation to study the effect of activator treatment of Class II malocclusions in the mixed-dentition period. A group of treated patients was compared with a similar group of untreated Class II malocclusion patients. The criteria for selection and matching of the patients in the two groups included age, sex, dental maloclusion, and observation time. Lateral cephalometric films before treatment, after treatment, and after the retention period were compared and revealed clinically and statistically significant differences between the activator group and the control group. Differences in mean changes are described as follows: 1. 1. The effect of treatment was usually of dentoalveolar origin with a major favorable change in position of the upper incisors. 2. 2. The lower incisors were slightly intruded without significant protrusion. 3. 3. The improvement of the relationship between the upper and lower molars was caused mostly by tooth movement within the dentoalveolar area. 4. 4. The average orthopedic effect of treatment was limited, in spite of individual cases with excellent response. A significant improvement of the anteroposterior relationship between the maxilla and the mandible was registered, as well as an increase in the lower face height and a slightly steeper mandibular plane angle. 5. 5. No differences in the amount of mandibular growth were recorded. 6. 6. Several years after the retention period the dentoalveolar treatment effect upon the maxilla was quite evident, with no sign of relapse.

The etiology and prediction of mandibular third molar impaction.

1. Skeletal Class II dental base relationship with a shorter, narrower, more acute angled madible was found in association with impacted third molars, compared with erupted teeth. 2. These differences were found at age 18+ years but were less obvious at age 10 to 11 years. 3. There was a reduced amount of mandibular growth in impacted third molar cases. 4. There was a slight tendency for impacted third molars to be larger than those which erupted. 5. The presence of a space between second and third molars in the early stages of development is not an indication that the third molar will erupt. 6. The developmental angulation of the third molar to the mandibular plane was higher in the impacted third molar group. 7. Accurate prediction of third molar impaction from radiographic measurements is not possible at age 10 to 11 years.