Dental changes and space gained as a result of early treatment of pseudo-Class III malocclusion

This study was designed to investigate the dental changes and the space gained following early treatment of pseudo-Class III malocclusion, using a simple fixed appliance. Twenty-one consecutively treated patients who had a pseudo-Class III malocclusion comprised the treated group. Fifteen untreated control subjects were used as matched controls for the three-year follow-up after completion of treatment. Lateral cephalograms and study models were analysed for the treated, the control and the follow-up group. The arithmetic mean and standard deviation were calculated for each variable, and paired t-tests were performed to assess the effects of treatment on the treated group. The Mann-Whitney test was performed to evaluate the difference between the follow-up group and the control group. Anterior crossbites and mandibular displacements were eliminated after the treatment. On average, the space gained as a result of the treatment was 4.7 mm in the upper arch (p < 0.001 degree). Comparison of the space available as a result of early treatment with the space required for alignment of posterior segments in the upper arch of the untreated control group indicated that there was enough space for the eruption of the canines and premolars as a result of early treatment; whereas, lack of space was evident in the untreated controls. In conclusion, a pseudo-Class III malocclusion, proclination of the upper incisors and/or retroclination of the lower incisors contributed to the correction of anterior crossbite and the elimination of mandibular displacement. Proclination of the upper incisors, utilisation of leeway space, and arch-width increase provided the space required for eruption of the premolars and canines.     

Diagnostic criteria for intraarticular T.M. disorders

Epidemiological investigations about the prevalence of TMJ ID and osteoarthritis have largely reported the symptoms and signs associated with these disorders without specific criteria to establish the diagnosis. In this study, specific diagnostic criteria have been developed, using historical, clinical and tomographic items that are predictive of the presence and stage of TMJ internal derangement. The diagnostic criteria were compared to arthrotomography to assess their diagnostic accuracy. Overall, the percent agreement was 75%. The predictability of specific stages of TMJ ID varied. Overall, sensitivity and specificity of the criteria were acceptable. The diagnosis of osteoarthritis was predicted only with tomography. Utilization of these diagnostic criteria in epidemiological studies is valid due to their high overall predictiveness when applied to a large population.     

Correction of a severe Class III malocclusion.

The success of early orthopedic treatment in patients with Class III anomalies depends on facial skeletal development and type of treatment. This case report describes the treatment of a 12.6-year-old girl who had a severe Class III malocclusion with a 6-mm anterior crossbite, a deep overbite, a narrow maxilla, and unerupted maxillary canines. The treatment plan included rapid palatal expansion to expand the maxilla, reverse headgear to correct the maxillary retrognathia, a removable anterior inclined bite plane to correct the anterior crossbite and the deep overbite, and fixed edgewise appliances to align the teeth. One canine was brought into alignment, but the other was placed in occlusion in its transposed position. Ideal overjet and overbite relationships were established, and the final esthetic result was pleasing.     

Surgical-orthodontic approach to skeletal class III malocclusion.

Twenty-nine adult patients with skeletal Class III malocclusion were treated by combined surgical-orthodontic management. A thorough analysis enabled us to point out the exact location and degree of the deformity and was of great help in determining the appropriate types of treatment. Corrections were made in 12 patients by the mandibular body ostectomy in the premolar region; the curved oblique osteotomy, in which the ascending ramus was cut obliquely on a curved line from the anterior border of the ramus to the angle, was used for the treatment of the remaining 17 patients. The resulting profile and occlusal improvements were satisfactory, Preoperative orthodontic treatment such as leveling of the dental arches, expansion of the upper dental arch to accommodate the maxilla to the mandible, correction of the upper and lower incisal inclinations, extraction of the premolars to decrease horizontal discrepancy or alignment of malpositioned teeth, and postoperative adjustment were effective in providing definite changes in profile and a stable occlusion-an important factor in the prevention of postoperative relapse.     

Orthodontic and surgical aspects. Class III malocclusion

Skeletal Class III malocclusions are the result of deficient maxillary growth, excessive mandibular growth or a combination of both. Vertical as well as transverse dimensions can be disturbed too. Skeletal, dental and functional characteristics are described briefly. Treatment planning is outlined with special reference to the pattern of development during different growth stages and its consequences for therapeutical intervention. At last possibilities and limitations of surgical/orthodontic correction of the skeletal discrepancy and its dental compensations are discussed.     

An unusual Class III malocclusion

A nine year old caucasian boy presented with bilateral double upper central incisors in Class III relationship. In addition 4 showed an abnormal root morphology and path of eruption. The double teeth were retained and the incisor relationship was corrected orthodontically. Following surgical exposure, 4 erupted favourably.     

Effect of protraction headgear on Class III malocclusion.

Ten patients with skeletal Class III malocclusion in the early mixed dentition who were treated with maxillary expansion appliance and protraction headgear were compared with reasonably matched controls. Significant orthopedic effects were found after as little as 6 months of treatment. Cephalometric analysis revealed that the correction of Class III malocclusion was primarily a result of forward and downward movement of the maxilla and backward rotation of the mandible. The clinical result of one patient treated with this appliance is used to demonstrate the importance of force magnitudes and directions, as well as the design of the appliance, to the success of the treatment.     

Gender differences in Class III malocclusion

This study evaluated gender differences in the cephalometric records of a large-scale cross-sectional sample of Caucasian subjects with Class III malocclusion at different developmental ages. The purpose also was to provide average age-related and sex-related data for craniofacial measures in untreated Class III subjects that are used as reference in the diagnostic appraisal of the patient with Class III disharmony. The sample examined consisted of 1094 pretreatment lateral cephalometric records (557 female subjects and 537 male subjects) of Caucasian Class III individuals. The age range for female subjects was between three years six months and 57 years seven months. The male subject group ranged from three years three months to 48 years five months. Twelve age groups were identified. Skeletal maturity at different age periods also was determined using the stage of cervical vertebral maturation. Gender differences for all cephalometric variables were analyzed using parametric statistics. The findings of the study indicated that Class III malocclusion is associated with a significant degree of sexual dimorphism in craniofacial parameters, especially from the age of 13 onward. Male subjects with Class III malocclusion present with significantly larger linear dimensions of the maxilla, mandible, and anterior facial heights when compared with female subjects during the circumpubertal and postpubertal periods.     

Treatment planning in Class III malocclusion

In Class III malocclusion, the overjet is reduced and may be reversed, with one or more incisor teeth in lingual crossbite. In the early mixed dentition, and in older patients with mild skeletal discrepancies, orthodontic treatment usually involves proclining the maxilliary anterior teeth into positive overjet. When the permanent dentition has established, orthodontic therapy is usually aimed at compensating for the underlying mild-moderate Class III skeletal discrepancy by proclining and retroclining the maxillary and mandibular incisors, respectively. In contrast, adolescent and non-growing patients with severe Class III skeletal discrepancies require a combination of orthodontic treatment and orthognathic surgery to correct the underlying skeletal pattern. Adolescent patients with moderately severe skeletal discrepancies require careful treatment planning because they are often at the limits of orthodontic compensation, and further mandibular growth may prevent a stable Class I occlusion from being maintained with growth. In this situation, treatment should be limited to aligning the maxillary arch, accepting that orthognathic surgery will be required to correct the underlying Class III skeletal discrepancy when skeletal growth has been completed. This article will inform dental professionals about the aetiology, assessment, diagnosis and treatment of patients with Class III malocclusions. Specifically, the types of orthodontic treatment that can be completed at the various stages of dental development and skeletal growth will be discussed.     

Early treatment of Class III malocclusion

Optimum treatment timing for orthodontic problems continues to be one of the more controversial topics in orthodontics. Especially regarding the correction of Class III malocclusion, there is little consensus as to proper timing or methods for correcting these problems. The orthopedic approach for growth modification is usually limited to children with growth remaining subjected to non hereditary pattern. If the skeletal malocclusion is within the range of an orthodontic treatment, fixed orthodontic appliances with dentoalveolar compensation mechanism can achieve a normal occlusion. Otherwise in patients with a severe skeletal discrepancy, it will be necessary to consider a combined surgical and orthodontic approach. The purpose of this study was to describe treatment planning according to the age and to the initial diagnosis. The management of skeletal Class III malocclusion is still a challenge to orthodontists especially because of relapse due to the late growth of the mandible.     

Components of adult class III malocclusion

To identify the skeletal and dental relationships of adults who have class III malocclusion, lateral cephalograms of 302 adult patients who had a class III molar and cuspid relationship were traced. Ninety-four of the patients had had presurgical orthodontic treatment and 208 had not. The tracings were digitized, and the following sets of measures were analyzed: maxillary skeletal position; maxillary dentoalveolar position; mandibular dentoalveolar position; and mandibular skeletal position. In addition, the mandibular plane angle and lower anterior facial height were measured as an indicator of vertical facial dimensions. None of these values demonstrated significant gender differences except lower anterior facial height; therefore, the subjects were treated as a group. Although there was considerable variation among patients, the most common combination of variables was a retrusive maxilla, protrusive maxillary incisors, retrusive mandibular incisors, a protrusive mandible, and a long lower facial height.     

Mandibular position in class III malocclusion

Lateral skull radiographs of 66 subjects with Class III malocclusion, characterized by lingual occlusion of the upper incisors and a degree of overbite, taken before and after treatment were compared with a Control Group of similar mean age and interval between films. Vertical, Horizontal and Oblique measurements were made to establish the part played by overclosure and anterior displacement of the mandible in the aetiology of Class III malocclusion. The results suggest that both may play a part but that the former is of more general significance than the latter.     

Cranial strains and malocclusion: III. Inferior vertical strain

This article describes the Inferior Vertical Cranial Strain, one of the seven possible cranial strains that are discussed in this series of articles. Clinicians have to understand cranial strains to better treat their patients. There is a major link between the malocclusion we see and the underlying physiology of the patients. With airway restriction, it is necessary to understand the cranial, postural and facial factors as well as the soft tissue contribution for a more effective overall treatment of the patient.