Postretention assessment of deep overbite correction in Class II Division 2 malocclusion

The purposes of this study were to evaluate the long-term stability of deep overbite correction in Class II Division 2 malocclusion and to search for predictors of postretention overbite. The sample of 62 (31 males, 31 females) was limited to Class II Division 2 patients with initial deep overbite and successful orthodontic treatment as judged clinically at the end of treatment. Study models and cephalograms were analyzed before treatment, after treatment, and out of retention (average 15 years). The sample was divided into two groups according to the degree of postretention overbite: Group 1 (N=33; overbite > or = 4.0 mm at T3, mean = 5.17 +/- 0.87) and group 2 (N=29; overbite <4.0 mm at T3, mean = 2.95 +/- 0.87). The results showed that patients with very upright pretreatment maxillary and mandibular incisors tended to have deeper initial overbite and a tendency to return to their original relationship by the postretention stage. Posttreatment vertical growth contributed to maintenance of overbite correction. By stepwise multiple regression analysis, initial overbite was selected as the most important predictor of postretention overbite. Initial overbite was positively related with postretention overbite.

An appraisal of the Peer Assessment Rating (PAR) Index and a suggested new weighting system

The PAR Index was developed to measure treatment outcome in orthodontics. Validity was improved by weighting the scores of some components to reflect their relative importance. However, the index still has limitations, principally due to the high weight assigned to overjet. Difficulties also arise from the application of one weighting system to all malocclusions, since occlusal features vary in importance in different classes of malocclusion. The present study examined PAR Index validity using orthodontic consultant assessments as the 'Gold standard' and clinical ranking of occlusal features and statistical modelling to derive a new weighting system, separate for each malocclusion class. Discriminant and regression analyses were used to derive new criteria for measuring treatment outcome. As a result a new and more sensitive method of assessment is suggested which utilizes a combination of point and percentage reductions in PAR scores. This was found to have better correlations with the 'Gold standard' than the PAR nomogram.

Cephalometric morphology of Chinese with Class II division 1 malocclusion

AIM

To investigate the craniofacial pattern of southern Chinese children with Class II Division 1 malocclusion and to compare with Chinese population norms and Caucasians with Class II Division 1 malocclusions.

MATERIALS

Lateral cephalograms obtained from 105 Chinese subjects with Class II Division 1 malocclusion.

RESULTS

There were no significant sex differences and subsequently the data were pooled. Except for the maxillary plane angle and the angle of the lower incisor relative to the mandibular plane, all of the selected dental-skeletal angular measurements showed significant differences between Chinese with Class II Division 1 malocclusion and Chinese norms.

CONCLUSION

Compared with Caucasians, Chinese with Class II Division 1 malocclusion have more prognathic maxillas, less retrusive mandibles, flatter chins, steeper mandibular plane angles and more proclined maxillary incisors.

Clinical and magnetic resonance findings in the temporomandibular joints of patients before and after orthognathic surgery

It is difficult to achieve the correct position of the condyle in the temporal fossa during orthognathic surgery in angle class II patients with disorders of the temporomandibular joint. This led us to examine the TMJ of 25 of our own patients before and shortly after orthognathic operations. We recorded the clinical and magnetic resonance imaging findings of the temporomandibular joint preoperatively and three months postoperatively. The patients had skeletal class II dysgnathia and had been treated with fixed orthodontic appliances for a mean of two years and three months before operation. Operation resulted in a mean reduction of maximal incisor distance of 12 mm. In five of the 25 patients, the pattern of mouth-opening changed. Nine patients had less pain than before surgery, and nine had fewer abnormal joint sounds. The magnetic resonance imaging showed displacement of the articular disc in 38 of the 50 joints preoperatively and in 28 postoperatively. Degenerative joint changes were not improved by operation. Improvement of the disc position was achieved by repositioning of the condylar-disc complex during orthognathic surgery in angle class II patients. Clinical and magnetic resonance imaging findings regarding the temporomandibular joint in class II patients correlated significantly both preoperatively and postoperatively.

Occlusal changes from adolescence to adulthood in untreated patients with Class II Division 1 deepbite malocclusion

A sample of 47 untreated children (M 32:F 15) with Class II Division 1 (II/1) deep-overbite malocclusion was collected from a group of patients who declined orthodontic therapy. Longitudinal records consisted of plaster dental casts and lateral cephalograms at original diagnosis and plaster dental casts at a follow-up observation in adulthood, an average of 11.5 years later. To study retrospectively natural changes in dental occlusion during this interval, plaster-cast millimetric measurements were recorded of sagittal dental relationships (first molar and canine), overjet, overbite, and crowding/spacing at the two registrations. Results showed statistically significant improvements in untreated II/1 deepbite malocclusion from adolescence to adulthood for all measured occlusal variables except development of mild crowding. Therefore, assumptions that untreated II/1 distoclusion will worsen with age appear to be unfounded. The evidence indicates that the absence of orthodontic correction for adolescent patients with Class II Division 1 deepbite malocclusion will not usually lead to measurable occlusal deterioration in young adulthood.

Early developmental traits in class II malocclusion

The occlusal traits of Class II occlusion in the deciduous dentition include distal terminal plane of the second deciduous molars, distal canine relation, large overjet, and large overbite. Other findings are narrow upper dental arch and maxillary base and poor anterior spacing. Skeletally, Class II children differ less from normal children. The cranial base, including the base flexure, and the maxilla are normal. The mandibular corpus and lower facial height are short, the gonial angle is large, and the dentoalveolar position of the mandible is retruded. The height of the ramus is normal, as is the skeletal position of the mandible, with the exception of the chin, which becomes slightly retruded after 5 years of age. As most skeletal traits of Class II occlusion develop later than the occlusal characteristics, it is suggested that no evidence can be found for a skeletal Class II growth pattern in the deciduous dentition. The deficient transversal growth of the maxilla and the sagittal growth of the mandible seem to cause the typical Class II occlusion. Further skeletal changes are likely to develop as secondary adaptations.

Dentoskeletal morphology in children with Deckbiss

A comparison of dentoskeletal morphology in 176 Deckbiss malocclusions with Class I molar relationship (Class I/2) and 156 Deckbiss malocclusions with Class II molar relationship (Class II/2) was performed using lateral cephalometric radiographs. Children at the ages of 8 to 10 years and 11 to 13 years were evaluated. The results of the study revealed broad variations in the variables analysed. A relatively short lower face and an obtuse interincisal angle were the only consistent features of the Deckbiss (Class I/2 and Class II/2). Otherwise the dentoskeletal morphology of the Deckbiss was untypical. When comparing the Class I/2 and Class II/2 samples the following morphological traits were more pronounced and/or more frequent in the Class II/2 sample: 1. mandibular retrusion, 2. skeletal Class II jaw base relationship, 3. mandibular plane angle reduction, 4. jaw base hypodivergency, and 5. upper incisor retroclination. Lower incisor retroclination, on the other hand, was more pronounced and more frequent in the Class I/2 sample. Age affected exclusively the Class I/2 sample: maxillary and mandibular retrusion were seen more frequently in the younger than in the older subjects.

[The Bimler method in the treatment of sagittal shift of the skeletal base in Class II division 1 malocclusion]

Inadequate sagittal development of the mandible (class II, division 1 malocclusion), is one of the most frequent in dentofacial malformations. We present the Bimler "gebissformer", removable and functional appliance and its tridimensional action. The treatment can be started during the deciduous dentition or in mixed dentition. Therapeutic results, increase of SNB angle, maxillary expansion, and reduction of the deep bite are presented. While therapeutic failure is observed in 30% of the cases (by absence of tissular response or poor patient compliance), the stability of the results in 70% of the remaining cases and its total inocuity make this appliance an interesting method of treatment.

Craniofacial morphology in Chinese and Swedish children with Angle Class I and Class II occlusal relations

The purpose of this study was to compare the craniofacial morphology of a group of Chinese children from northern China with a group of Swedish children. Each ethnic group comprised 20 boys and 20 girls with Class I occlusion, and 20 boys and 20 girls with Class II occlusion. The ages of the children ranged from eight to ten years. Lateral cephalometric radiographs were used for the recording of a number of skeletal, dental, nasopharyngeal airway, and hyoid bone variables. The results of the comparisons of the two ethnic groups showed that the antero-posterior dimensions of the anterior cranial base and the maxilla in the Chinese children were significantly smaller than the corresponding dimensions in the Swedish children. The mean values of anterior and posterior face heights, inclination of the upper incisors, and protrusion of the lower incisors, were significantly greater in the Chinese than in the Swedish samples. In the median plane, the size of the nasopharyngeal airway was significantly greater in the Chinese than in the Swedes. This difference was due to the fact that the soft tissues covering the posterior nasopharyngeal wall were thinner in the Chinese children than in the Swedish children. In general, the ethnic differences were the same in the Class I and the Class II groups. The differences in some of the dental and skeletal characteristics found between northern Chinese and Caucasian-children are similar to previously described differences between southern Chinese and Caucasian children.

A prospective evaluation of Bass, Bionator and Twin Block appliances. Part I--The hard tissues

A prospective clinical study with a random allocation of 47 adolescent patients to three different functional appliance groups was established and compared with an untreated control group over a 9-month period. Treatment was undertaken with either a Bionator, Twin Block, or Bass appliance. Pre- and post-treatment cephalograms were used to quantify the skeletal and dentoalveolar changes produced by the appliances and compared with those observed in the control group as a result of growth. Both the Bionator and Twin Block appliances demonstrated a statistically significant increase in mandibular length (3.9 +/- 2.7 mm; 3.7 +/- 2.1 mm, respectively) compared with the control group (P < 0.05), with an anterior movement of pogonion and point B. Highly statistically significant increases (P < 0.01) were seen in lower face heights for all the appliance groups compared with the control group. The Twin Block group showed the least forward movement of point A due to a change in the inclination of the maxillary plane. The Bionator and Twin Block groups showed statistically significant reductions in the inclination of the upper incisors to the maxillary plane (P < 0.05). The Bass group showed minimal change in the inclination of the lower labial segment to the mandibular plane. The Bionator group demonstrated the greatest proclination of the lower labial segment (4.0 +/- 3.6 degrees). Clinically important changes were measured in all the appliance groups when compared with the control group. Differences were also identified between the functional appliance groups. The Twin Block appliance and, to a lesser extent, the Bionator appeared the most effective in producing sagittal and vertical changes.

Correlations between condylar characteristics and facial morphology in Class II preadolescent patients

The aim of this retrospective study was to determine correlations between condylar characteristics measured from preorthodontic tomograms of preadolescents and their facial morphologic characteristics. The sample consisted of 136 patients displaying a Class II malocclusion, a vertical or horizontal skeletal growth tendency, and ranging in age between 10 years 0 months and 12 years 6 months for males and 9 years 0 months and 11 years 6 months for females. Two groups were established: the vertical group had 68 patients, 36 males and 32 females, (average pretreatment age, 11 years 0 months); the horizontal group also had 68 patients, 29 males and 39 females, their average pretreatment age was 10 years 9 months. The central cut of axially corrected lateral tomograms of the left and right temporomandibular joints for each group was randomized, blinded, and traced for condyle/fossa measurements including: anterior, superior and posterior joint space; condylar head and posterior condylar ramus inclination; condylar neck width; and condylar shape and condylar surface area. A logistic discriminant analysis with significance values set at p < 0.05 was used to determine the most reliable condylar characteristics to predict facial morphology. A cluster analysis was completed on the significant variables to form three clusters. Numeric ranges separating these clusters were then calculated. Chi-square tests measures of association were computed for significant variables and tested for associations between facial morphologic characteristics. Condylar head inclination and superior joint space proved to be significantly correlated to facial morphology (p values ranged from 0.010 to 0.018). Patients with vertical facial morphologic characteristics displayed decreased superior joint spaces and posteriorly angled condyles. Increased superior joint spaces and anteriorly angled condyles were significantly correlated to patients with a horizontal facial morphology. No significant correlations between the other condylar characteristics and facial morphology were determined.

Mandibular changes in persons with untreated and treated Class II division 1 malocclusion

The growth potential of individuals with Class II malocclusions is of interest to the practicing orthodontist because such malocclusions constitute a significant percentage of cases. The purpose of this study was to evaluate on cross-sectional and longitudinal bases the changes in mandibular length and relationship and maxillary-mandibular relationships in untreated Class II subjects from deciduous to permanent dentition and also to evaluate the effects of orthodontic treatment, with and without the extraction of first premolars, on these relationships. Class II samples were compared with matched normal, untreated individuals. The Class II division 1 (Class II/1) untreated sample comprised 30 subjects, 15 males and 15 females. Each subject had a complete set of data at three stages of dental development-namely, Stage I, after the completion of eruption of the deciduous dentition; Stage II, at the time when the permanent first molars and most of the incisors have erupted (i.e., in mixed dentition); and Stage III, at the completion of eruption of the permanent dentition, excluding third molars. The Class II treated sample comprised 44 subjects (21 males, 23 females) treated with four first-premolar extractions and 47 subjects (20 males, 27 females) treated without extraction. Treatment was accomplished with the use of an edgewise appliance, appropriate extraoral traction, and Class II elastics. The extraction decision was based mainly on the presence of crowding and profile consideration. Records on 35 normal subjects (20 males, 15 females) were available from the Iowa Longitudinal Facial Growth Study. Cephalograms for the normal individuals were matched to the corresponding ages of the Class II cases. With regard to these findings, few consistent differences were noted between the untreated Class II/1 and normal subjects on cross-sectional comparisons. The differences in mandibular length and position were more evident in the early stages of development than at later stages. Longitudinal comparisons of growth profiles indicated that the growth trends were essentially similar between the untreated Class II/1 and normal subjects in the various parameters compared. The comparisons of growth magnitude indicated the presence of greater skeletal facial convexity in the untreated Class II/1 subjects, accompanied by a tendency for a more retruded mandible. Initial comparisons between the Class II/1 treated groups and normal subjects indicated that the Class II/1 malocclusions were associated with a larger overjet, deeper overbite, and greater ANB angle. After a 5-year treatment and observation period, an overall "normalization" in the mandibular and maxillary-mandibular skeletal relationships was noted in the treated Class II/1 subjects in both the extraction and the nonextraction groups compared with normal subjects. The changes were more pronounced in the extraction group.

Soft tissue adaptability to hard tissues in facial profiles

The purpose of this study was to investigate soft tissue adaptability to hard tissue. A canonical correlation analysis was performed in an attempt to assess the relationships between hard tissue structure and soft tissue profile in the static state. For the dynamic study, multiple-regression analysis was performed to identify the changes of soft tissue profiles associated with the retraction of upper and lower incisors. The samples comprised lateral cephalograms from 297 Japanese women for the static canonical correlation analysis and 32 sets of lateral cephalograms of pre- and posttreatment adult orthodontic patients for the dynamic multiple-regression analysis. In the static state, the vertical dimension of lower facial height and the position of the lower incisors were associated with the thickness of the upper-lip vermilion and soft tissue B, and the horizontal relationships between upper- and lower-jaw positions were associated with the thickness of upper lips and of pogonion (soft tissue chin). In the dynamic state, the results indicated that the changes of stomion and lower lip could be predicted and strongly reflected the changes of the hard tissue. On the contrary, the change of the upper lip showed a weaker association with the hard tissue changes. Predictions of chin form described by the soft tissue B and soft tissue pogonion were less accurate than estimates of upper- and lower-lip form. Chin form was influenced by the hard tissue structures such as ANB angle and lower-facial height rather than by changes in lower- and upper-incisor retraction.

Möbius syndrome with dental involvement: a case report and literature review

The clinicopathological findings on a 17-year-old female with the Möbius/Moebius syndrome are reported. The signs and symptoms of this neuromuscular condition include congenital bilateral or unilateral palsies of the facial and abducens cranial nerves and a broad scope of multisystem abnormalities. A case of unilateral deficiencies of cranial nerves VI and VII, congenital ectrodactyly of toes, and multiple congenitally missing primary and permanent teeth is reported. A review of the literature reveals various ideas regarding the diversity of symptoms and the etiology of the syndrome. The purpose of this article is to report oral manifestations, such as congenitally missing teeth, associated with Möbius syndrome.

[One year observation of craniomandibular structure changes of skeletal Class II patients in early permanent dentition]

OBJECTIVE

To study the craniomandibular growth of skeletal class II patients in early permanent dentition so that demonstrate malocclusion development and decide orthodontic treatment opportunity.

METHODS

Forty skeletal class II patients in early permanent dentition were selected at random and observed for one year. The lateral cephalometric X-ray films were taken before and after observation for every patient, then Downs analysis and doublet test were made.

RESULTS

Female patients' jaws relation didn't change in early permanent dentition, but upper incisors were more protrusive than before, and lower incisors inclined lingualy. Male patients' mandible grew upward and forward, but the absolute value of small change.

CONCLUSION

It is necessary to treat skeletal class II deformities early.

Two-phase treatment of an Angle Class II division 2 malocclusion

This case report describes a two-phase approach to the treatment of an Angle Class II division 2 malocclusion in a growing boy. The first phase utilised a functional appliance (Clark Twin Blocks) during puberty and achieved a pleasing improvement in the facial profile. The second phase involved a fixed upper and lower Begg appliance without extractions, followed by retention. An unexpected complication was the failure of the lower left second molar to erupt; surgical removal of cystic elements surrounding this tooth, followed by traction and, later, mechanics to correct the buccal cross-bite, eventually corrected its position.

Effects of different vectors of forces applied by combined headgear

The effects of various directed forces applied by combined headgear were evaluated in this study. The study material consisted of 30 patients with Class II dental relationships and steep mandibular plane angles. Three groups of 10 patients each were formed. In the first treatment group, forces of 150 gm per side were used for the high-pull component and the cervical component. In the second treatment group, forces of 200 gm per side for the high-pull component and 100 gm per side for the cervical component were applied. In the third treatment group, forces of 100 gm per side were applied for the high-pull component and 200 gm per side for the cervical component. Distal tipping of upper molar was greatest in the third treatment group. Intrusion of the upper molar in the second treatment group and extrusion of the upper molar in the third treatment group were statistically significant. Changes in occlusal and mandibular plane angles showed significant differences between the groups.

Evaluation of orthodontic relapse using the cubic spline function

A sample of 72 orthodontically treated patients was reexamined many years out of retention. They had been treated either by the extraction of four premolars or without extractions. The average number of years between the end of treatment and the taking of follow-up records was 20, with a range of 12 to 35 years. Some conventional measurements were studied such as intertooth widths, arch perimeter, and incisor irregularity. In addition, a new method for comparison of arch form at different stages of treatment, which uses the cubic spline function, was used. Cases were grouped into extraction and nonextraction, and statistics were used to test the differences between the two groups. Correlations between the spline variables and conventional variables were computed, and multiple regression analysis was carried out using the spline variables as dependent variables. Some treatment and relapse changes were independent of whether the case was treated with extractions or not, whereas other trends were unique to one treatment group. The correlation analysis revealed strong relationships between variables that measured changes during the same treatment stage. There were also moderate correlations between some of the spline variables and the traditional measurements. Multiple regression analysis was used to account for changes in some spline variables, however, the usefulness of the model as a predictor is limited.

[Occlusal interference of lingual appliances: advantages or inconvenience]

Lingual orthodontics presents a few technical problems; when practicing it, it reveals a considerable amount of advantages. The occlusal interference of the lingual maxillary bite plane with the mandibular incisors generate contact forces. A moment of corono-vestibulary version will weight upon the upper incisor independently from teeth position. Actions regarding the mandibulary incisors are depending on their position according to the bite plane. An incisor axe in perpendicular position to the plan generates intrusion. A lingual position generates a moment of lingual version and vice versa. These actions have to be considered. They might be, according to clinical situation, beneficial or not.

[A forecasting trial of the dento-skeletal and cutaneous facial profile, as a function of sex, in Class II, division 1 malocclusion, using regression analysis of the coordinates]

For a pattern of 36 leucoderm subjects, aged 12 years, with Class II, division 1, prediction of results are been calculated, in each sex, proceeding bony and cutaneous points coordinates, in axis defined by S-N, with "regression" method. Bony, dental and cutaneous profiles expected 3 years afterwards can be established in a personalized way, as well as correspondent security limits. A logical make easy utilisation of this process.