Treatment outcomes of growing Class II Division 1 patients with varying degrees of anteroposterior and vertical dysplasias, Part 2. Profile silhouette evaluation

The purpose of this study was to evaluate pretreatment and posttreatment soft tissue profiles of 4 groups of growing Class II Division 1 patients treated with fixed orthodontic appliances and headgear. One hundred patients were grouped according to the severity of their initial retrognathia and vertical skeletal status. Standardized pretreatment and posttreatment profile silhouettes of each patient were randomized and projected for scoring by panels of lay persons and orthodontic residents. Statistical analysis consisting of nonparametric procedures showed that (1) as the initial skeletal discrepancies between the 4 groups worsened, the initial profiles were judged to be more unattractive (P <.001); (2) there was no perceived difference in the final profiles between the 4 groups; and (3) significantly greater improvement was measured for those with greater initial skeletal discrepancies (P <.05). This study demonstrated that, with appropriate and timely treatment with fixed orthodontic appliances and headgear, growing Class II Division 1 patients can undergo significant profile improvement, and, on average, even those more severely affected can achieve profile improvement so that they can be judged as attractive as those initially less severely affected.

Class II treatment success rate in 2- and 4-premolar extraction protocols

This study compared the occlusal success rate of Class II orthodontic treatment results with either 2- or 4-premolar extraction protocols. Group 1 comprised dental study models of 81 patients treated with 2 premolar extractions, and group 2 comprised dental study models of 50 patients treated with 4 premolar extractions. The initial mean ages of the groups were 13.9 and 12.9 years, respectively. Grainger's treatment priority index (TPI) was used to assess the initial and final occlusal status of each patient. Individual variables, such as maxillary canine anteroposterior positioning, overjet, and overbite improvements were also evaluated. Independent t tests were used to compare the variables at the pretreatment and posttreatment stages and their improvement between the groups. The results showed a statistically significant difference in most of the variables and in their improvement at the end of treatment between the groups. The variables showed a better dental relationship in group 1, and the improvements in group 1 were larger than in group 2. Treatment of Class II malocclusion with 2 premolar extractions gives a better occlusal success rate than treatment with 4 premolar extractions.

Treatment outcomes of growing Class II Division 1 patients with varying degrees of anteroposterior and vertical dysplasias, Part 1. Cephalometrics

The purpose of this retrospective study was to evaluate the differences in orthodontic treatment outcomes for 5 groups of growing Class II Division 1 patients with various anteroposterior and vertical skeletal dysplasias. Pretreatment and posttreatment cephalograms of 100 patients were evaluated for soft and hard tissue treatment effects and differences between groups. Changes from pretreatment to posttreatment differed between groups in correction of overjet and change in ANB angle (P <.05). Those with the largest skeletal dysplasias had the greatest skeletal correction but also retained the largest ANB angles posttreatment. Additional correction was achieved through dentoalveolar change with the greatest uprighting of maxillary incisors occurring in patients who initially were the most severely affected (P <.05); this effect was accompanied by an increase in nasolabial angle. All groups had similar changes in mandibular incisor positions, and final positions of the mandibular incisors did not differ between groups. Compared with norms, Z angles and facial contour angles showed discrimination between the most and least severely affected patients based on combined anteroposterior and vertical dysplasias (P <.05). However, there were no clear-cut divisions between the groups, especially with regard to soft tissue cephalometric outcomes. Further evaluation of profile esthetics follows in Part 2. We conclude that conventional orthodontic therapy successfully corrects Class II Division 1 malocclusions in growing patients through a combination of skeletal and dentoalveolar changes, with the greatest changes occurring in patients who initially have the most severe skeletal dysplasias.

Unilateral Angle II in functional lateralities

The aim of this study was to explore unilateral Angle II-type malocclusion prevalences in functionally true right-sided (TRS) and non-right-sided (NRS) children having one or more left-sided functions (eye, hand, foot). A half cusp sagittal relationship of the upper and lower M1 and Dm2 was determined on dental casts of 1423 young American black and white children in a cross-sectional sample with the mean age of 8.5 years (range 6-12 years). Hand, foot and eye preferences were recorded at the age of 4 years during the Collaborative Perinatal Study. The prevalences of symmetric bilateral Angle I and II and asymmetric unilateral Angle II right and Angle II left cases were compared between TRS and NRS children using Chi-square analysis. In general, unilateral Angle II right occurred in 9 per cent of the population and Angle II left in 6.5 per cent. In moderate non-right sideness (two-thirds of left dominant functions), these proportions were 17 and 3 per cent, respectively, and in true right sidedness 8 and 6 per cent, respectively. TRS subjects were more symmetric (bilateral Angle I or II in 85 per cent of cases) than NRS children (80 per cent), and the differences were statistically significant (P < 0.02). These results highlight the anatomical relationships of structures supporting the occlusion and the symmetry/asymmetry of the neurocranium, cranial base, masticatory apparatus, and probably also the sidedness and the growth-stimulating effect of lateralized jaw function. Based on the results and considering earlier observations on brain asymmetry in functional lateralities, it can be hypothesized that a normal symmetric sagittal occlusal relationship is based on unilateral sagittal compensatory growth to maintain optimal bite, challenging early preventive orthodontic treatment in suspect unilateral Angle II cases.

Crown-root shape of the permanent maxillary central incisor

This study aimed to determine whether the lateral cephalometric crown-root shape differs among the permanent maxillary central incisor in Class I, Class II division 1, Class II division 2 and Class III malocclusions and to identify the nature of any differences. Of the 499 lateral cephalograms recorded at a university orthodontic clinic during 2001, 361 satisfied the inclusion criteria. Sixty cephalograms were selected from the four malocclusion groups and were digitized in random order. The configurations of the 10 landmarks characterizing the crown-root shape of the permanent maxillary central incisor were then optimally superimposed using Procrustes algorithms. Discriminant analysis of the principal components of shape determined the incisor shape differences between the malocclusion groups. The crown-root shape of the permanent maxillary central incisor did not differ significantly among the Class I, Class II division 1, and Class III groups (P > .05); however, the crown-root shape of the Class II division 2 permanent maxillary central incisor was significantly different (P < .001) from that of the Class 1, Class II division 1 and Class III. The shape discrimination involved axial bending of the Class II division 2 incisors. Principal components 1, 2, and 3 accounted for 63% of the Class II division 2 incisor shape variance, encompassing a shorter root, a longer crown, and axial bending of the incisor, in addition to a reduced labiopalatal thickness. These shape features could precipitate the development of a deep overbite in Class II division 2 malocclusion and may limit the amount of palatal root torque during fixed appliance therapy.

The pattern of malocclusion among orthodontic patients seen in Dental Centre, University College Hospital, Ibadan, Nigeria

The aim of this study was to analyse the malocclusion pattern among patients who presented for treatment in the Orthodontic Unit of the Dental Centre, University College Hospital, Ibadan, as baseline data for proper treatment planning, teaching and further research. A total of 289 subjects aged 5-34 years with mean age of 10.6 +/- 1.5 (S.D.) years were seen. Angle's classification of molar relationships among those seen is as follows: class I - 76.5%, Class II - 15.5% and Class III - 8.0%. There was increased overjet in 16.2% of the patients, reduced overjet in 0.7% while 2.1% had reversed overjet. Other occlusal abnormalities included: increased overbite (3.8%), reduced overbite (1.4%); anterior open bite (5.2%; crossbite (8.4%) and scissorsbite (0.6%). Crowding, spacing and retained primary incisors constituted 29.7%, 1.4% and 40.1%, respectively. Delayed eruption of canine (1.0%), Bimaxillary protrusion (0.7%), incompetent lips (0.7%), supernumerary teeth (0.7%) malformed tooth (0.3%), mandibular deviation on closure (1.0%) and oral habits (4.5%) were other forms of malocclusion diagnosed. Males were found to have significantly more of classes II and III molar relationships than females (P < 0.05). Occurrence of retained primary teeth as well as overjet deviations from normal were significantly higher in females (P < 0.05). No significant sex differences were found in the other occlusal disorders (P > 0.05): The findings were comparable with previous epidemiological surveys in other parts of the country.

Readiness for orthognathic surgery: a survey of practitioner opinion

The purpose of this study was to determine if a general consensus exists among orthodontists regarding the features of an adequate presurgical setup. A questionnaire was developed to assess the importance of 12 criteria for surgical readiness. Each criterion was rated on a 5-point scale (1 = Unimportant, 5 = Critical). This questionnaire was sent to 104 randomly selected, board-certified orthodontists in the United States and Puerto Rico. Usable questionnaires were returned by 57 respondents (55% response rate). The highest and most consistent ratings were given for Arch Compatibility in the transverse dimension (mean = 4.66, SD = 0.55), Crossbite (mean = 4.57, SD = 0.63), and Torque of the Anterior Teeth (mean = 4.38, SD = 0.73). Further analysis showed a correlation between surgical experience of the orthodontist and a higher rating of importance for Torque of the Mandibular Teeth (Spearman r = 0.38), Torque of the Maxillary Teeth (Spearman r = 0.37), and Torque of the Anterior Teeth (Spearman r = 0.28). These results suggest that as orthodontists gain surgical experience, they attribute more importance to correcting the torque of the teeth. Also, the relatively large differences in opinion regarding presurgery orthodontic setup support a need for further research and/or educational effort regarding what criteria are important before surgery.

A multicenter interracial study of facial appearance. Part 2: A comparison of intraoral parameters

PURPOSE

This article compares interracial or gender differences of six intraoral dental parameters among six racial groups (African American, Caucasian, Chinese, Hispanic, Japanese, and Korean).

MATERIALS AND METHODS

The same 253 patients participating in part 1 were included in this portion of the study to evaluate six intraoral parameters. The data were collected and analyzed using a one-way analysis of variance, followed by the Tukey-Kramer test for honestly significant difference when statistically significant differences were found (P < .05).

RESULTS

Women displayed significantly more gingival tissue in four of the six races, and African Americans displayed significantly more gingival tissue than any other race. Women had significantly more missing teeth than men in three of the six races studied. Japanese subjects had significantly fewer missing teeth and smaller maxillary central incisors than all other groups except Caucasians. Women had significantly narrower maxillary central incisors in three of the races. There was a significantly higher prevalence of Angle Class III relationships in Chinese subjects. The Japanese had significantly more Class II molar relationships than other races.

CONCLUSION

Racial and gender differences were found in gingival tissue display, the number of missing teeth, maxillary right central incisor crown width, and Angle molar classification, but not in the amount of vertical or horizontal overlap of the anterior teeth.

Class II division 1 malocclusions: the subdivision problem

The purpose of this study was to determine the frequency of occurrence of subdivisions, in Class II division 1 malocclusions. Sixty patients seeking orthodontic treatment at the dental college of King Saud University were selected. The results revealed that 45% of Class II division 1 patients examined had subdivisions. The most commonly affected side was the right (66.7%). Mandibular shift upon closure was noted in 36% of the subdivision cases. Mandibular asymmetry was noted in 62.6% of the patients. It can be concluded from this study that subdivisions are a frequent finding in Class II division 1 malocclusions. Appropriate diagnosis of these cases should be done early in the mixed dentition phase, to avoid developing dental or skeletal asymmetries that can persist throughout adulthood.

Mandibular advancement surgery in high-angle and low-angle class II patients: different long-term skeletal responses

The objective of this cephalometric study was to compare skeletal stability and the time course of postoperative changes in high-angle and low-angle Class II patients after mandibular advancement surgery. The subjects were 61 consecutive mandibular retrognathism patients whose treatment included bilateral sagittal split osteotomy and rigid fixation. The patients were divided according to the preoperative mandibular plane angle; the 20 patients with the lowest mandibular plane angle (20.8 degrees +/- 4.9 degrees ) constituted the low-angle group, while the 20 cases with the highest mandibular plane angle (43.0 degrees +/- 4.0 degrees ) represented the high-angle group. Lateral cephalograms were taken on 6 occasions: immediately before surgery, immediately after surgery, 2 and 6 months after surgery, and 1 and 3 years after surgery. Results demonstrated that the high-angle and low-angle groups had different patterns of surgical and postoperative changes. High-angle patients were associated with both a higher frequency and a greater magnitude of horizontal relapse. While 95% of the total relapse took place during the first 2 months after surgery in the low-angle group, high-angle patients demonstrated a more continuous relapse pattern, with a significant proportion (38%) occurring late in the follow-up period. Possible reasons for the different postsurgical response are discussed.

Treatment of a Class II Division 2 malocclusion with space reopening for a single-tooth implant

This case report describes the treatment of an adolescent girl with a skeletal Class II Division 2 malocclusion and impinging overbite. One of 2 previously extracted premolars had to be replaced by a single-tooth implant after adequate space reopening. An optimal overbite-overjet relationship was achieved through significant intrusion and proclination of maxillary and mandibular incisors. A horizontally impacted mandibular second molar was repositioned to ensure a 2-molar arch integrity. Resolution of the gingival smile line and favorable facial changes were also obtained.

[Proposal for a classification of Class II Division 1: contribution of Delaire's analysis]

Class II division 1 dental malocclusions are present in various forms depending on the site, direction and degree of discrepancy between the arches. The ability to recognize the origin of the malocclusion is essential to decide how, and when it is necessary to treat. In this study, the Delaire's analysis was performed for 111 individuals with a Class II division I malocclusion; a classification of these cases is proposed, according to the presence or the absence of a skeletal discrepancy. In 87% of the cases, a Class II division 1 dental malocclusion was associated with a Class II skeletal discrepancy (50% maxillary prognathism, 23.5% normal maxillary relationship and 13.5% maxillary retrognathism). The lines of the cranial base, the shape and size of the mandible varied considerably. In only 6% of cases, the dental malocclusion was associated with a skeletal Class I relationship, and in 7% of cases with a Class III relationship: it was often related to retruded mandibular teeth. It was shown that Class II division 1 dental malocclusions may result from differing causes: therefore, the identification of their etiology seems essential to provide the best possible treatment, at the right period in time.

Classification of occlusion reconsidered

Katz's quantitative modification of Angle's occlusion classification has been found to have a high intra- and inter-examiner agreement among orthodontists. In the present study an attempt was made to introduce a 'combined' system comprising Katz's modification and overjet/overbite millimetric measurements in order to attain a more meaningful and complete classification of malocclusion than is presently available. A group of 32 raters (16 orthodontists and 16 senior-year students) examined 14 study models twice, with an interval of at least 1 month between examinations. In total, 448 x 2 determinations were performed. The percentage agreement of the Angle, the modified and the 'combined' systems, as well as the performance of the orthodontists versus the students were compared using the paired t-test. The percentage agreement obtained by both orthodontists and students was highest for Katz's modification and lowest for Angle's method. The overjet/overbite measurements affected the agreement in Katz's modified technique. The orthodontists surpassed the students with respect to Angle's method (P = 0.025), whereas no statistically significant difference existed between orthodontists and students regarding Katz's modification or the 'combined' system. It is concluded that in view of the relatively low agreement in the 'combined' method, it cannot be recommended for clinical application. The Katz's modified method, on the other hand, may be a helpful supplement to Angle's classification.

Rapid palatal expansion in treatment of Class II malocclusions

A technique which combines the use of rapid maxillary expansion and fixed appliance in growing patients, is presented. The treatment in three patients with Class II division 1 malocclusion and different skeletal patterns is described, and relative advantages highlighted.

[Orthodontic preparation for orthognathic surgery. Various specific points]

Orthodontic preparation before orthognatic surgery must straighten teeth alignment to enable correct adaptation of the upper and lower arches. It must also rectify dento-alveolar abnormalities partially responsible for the dysmorphosis and which can hinder smooth articulation of the bones. Thus before and after the operation, the orthodontist will have to prepare and monitor the surgical splints used in posterior deficiencies.

The differences in the chronology and calcification of second molars between angle Class III and Class II occlusions in Japanese children

The purpose of this study was to examine the differences in the times of eruption and calcification of the permanent dentition between skeletal class III and class II groups. (And also to examine the relationship between the time of eruption and the type of malocclusion) Fifty-three children, ages seven to ten years, were selected. Of these, twenty-six children (twelve boys and fourteen girls) were Angle class III with minus ANB and twenty-seven children (eleven boys and sixteen girls) were Angle class II with five or more ANB. Panoramic radiographs and cephalometric radiographs were used. The panoramic radiographs showed that the calcification of the maxillary second molars in class II were earlier than in class III using Nolla's classification. There was no statistically significant difference, however, for mean values of calcification stages, using Nolla's classification, between boys and girls. The cephalometric and panoramic radiographs showed that the times of eruption and calcification were earlier in the maxillary second molars than in the mandibular second molars for class II. In contrast, the times of eruption and calcification were earlier in the mandibular second molars than in the maxillary second molars for class III. The times of eruption and calcification of the maxillary molars were significantly related to the length of the ANS-PNS. The longer the ANS-PNS, the earlier were the times of eruption and calcification. There was a significant relationship between the ANB angle and the time of eruption, as well as the ANB angle and calcification. The larger ANB had earlier calcification and chronology of maxillary second molars.

Herbst appliance treatment of Class II, division 2 malocclusions

The purpose of this investigation was to analyze quantitatively the sagittal skeletal and dental changes that contribute to occlusal correction in Herbst treatment of 14 Class II, Division 2 malocclusions. Forty Class II, Division 1 Herbst subjects were used for comparison. Lateral head films from before and after Herbst treatment were analyzed, according to the method of Pancherz. The results revealed that all patients were treated to Class I or overcorrected Class I molar and edge-to-edge incisor relationships. The maxillary and mandibular skeletal changes were similar in both examination groups. In the Class II, Division 2 subjects, sagittal molar and overjet corrections amounted to an average of 5.9 mm and 3.1 mm, respectively. When comparing the Class II, Division 2 with the Class II, Division 1 subjects, overjet correction was, for natural reasons, significantly larger (p < 0.001) in the Class II, Division 1 subjects. In the subjects with Class II, Division 2 malocclusions, the upper incisors were proclined (mean = 3.0 mm), whereas in the subjects with Class II, Division 1 malocclusions, the incisors were retroclined (mean = 2.3 mm). The lower incisors were on the average proclined more (p < 0.05) in the Class II, Division 2 subjects (mean = 3.4 mm) than in the Class II, Division 1 subjects (mean = 2.4 mm). For sagittal molar correction, no differences in tooth movements were seen between the two malocclusions groups. In conclusion, it was found that the Herbst appliance is most effective in the therapy of Class II, Division 2 malocclusions. Proclination of the lower incisors during treatment (anchorage loss) is advantageous in this type of malocclusion.

Comparison between cephalometric classification methods for sagittal jaw relationships

The present study evaluated how 2 widely used cephalometric sagittal analyses, ANB angle and WITS appraisal, classify skeletal classes I, II, and III in a random selection of 497 Finnish boys aged 4-20 years. This distribution was also compared with the visual inspection of cephalometric structures judged by 2 university instructors in orthodontics. The results showed remarkable differences and even sparked controversy concerning classification of the sagittal jaw relationships. The ANB angle and the WITS appraisal emphasized the role of class II based on a failure to distinguish the proportion of class I. The low-angle influence skewed the distribution of the ANB pattern in the class III direction, and the WITS pattern, conversely, towards class II. High- or low-angle influence had only minor effects on the visual inspection of cephalometric structures. This cross-sectional study showed an age-related decreasing mean value for the ANB angle and increasing mean value for the WITS appraisal, thus explaining the remarkable difference in the distribution of sagittal classes. However, the findings of age-related changes makes the use of the fixed norms questionable. For extreme or controversial cephalometric interpretations, visual inspection provides an essential aid in diagnosis and skeletal classification.

Cephalometric characteristics of Class II division 1 and Class II division 2 malocclusions: a comparative study in children

A comparison of dentoskeletal morphology in 347 Class II division 1 and 156 Class II division 2 malocclusions was performed using lateral cephalometric radiographs. Children at the ages of 8-10 years and 11-13 years were evaluated. The results of the study revealed broad variations in the variables analyzed. Skeletal Class II and Class III as well as hypo- and hyperdivergent maxillary/mandibular jaw base relationships were seen in both malocclusion samples. Noteworthy was the high frequency of cases with mandibular retrusion (Class II division 1 sample: 48% of the younger and 29% of the older subjects; Class II division 2 sample: 48% of the younger and 49% of the older subjects) and a short lower face (97%-100%). In conclusion it can be said that, except for the position of the maxillary incisors, no basic difference in dentoskeletal morphology exists between Class II division 1 and Class II division 2 malocclusions.

Orthodontic treatment planning by general dental practitioners

A group of 30 general dental practitioners were asked to plan treatment for a series of 10 Class II division 1 malocclusions of graded severity. The results were assessed against a gold standard provided by three consultants. Only 14 per cent of practitioner treatment plans agreed with the gold standard and agreement was worst for those cases requiring the use of headgear. When consultants and General Dental Practitioners (GDPs) were asked whether a case should be referred for advice before the GDP began treatment, 64 per cent of GDP decisions agreed with those of the consultants. On 13 per cent of occasions, however, the GDP would have initiated incorrect treatment without seeking consultant advice.