Crass H, Division 2

nalocctusion

Nonextraction

Steven A. Hershcopf, DDS* South Windsor, New Britain, Conn.

A case report of a Class If, Division 2 malocclusion with an orthognathic maxilla and a retrognathic mandible is presented. The patient was an ll-year-old boy; the prognosis for future growth was excellent. This Class I!, deep bite skeletal pattern was corrected with cervical headgear and a 0.002 x 0.028inch edgewise appliance. The correction of a Class II skeletal discrepancy can be accomplished with a variety of treatment methods. Regardless of which approach the orthodontist chooses, a reduction in this skeletal difference facilitates correction of the malocclusion and improves facial balance.

Presented to the American Board of Orthodontics in partial fulfillment of the requirements for the certification process conducted by the Board. *In private practice. fl/4/10419

It appears that an untreated Class II malocclusion will remain such unless there is a dramatic and significant intervention that creates an alteration in growth and development or position of the teeth. This is stated by Brodie': "The most important single finding is that the morphogenetic pattern of the head is established by the third month of post-natal life or perhaps earlier and that once attained does not change." Ricketts,2 although not in complete agreement, clearly states that in his sample of untreated Class II malocclusion cases, "For the most part angle SNA did not change and the malocclusion got worse instead of improving." Contemporary orthodontics began its revival of extraoral forces to correct Class II malocclusions with the studies of Kloehn, a'4 whose corrections with extraoral anchorage were, "aimed at slowing the forward growth of the maxilla while the mandible and mandibular teeth

Fig. 1. Facial and intraoral photographs at beginning of treatment, 11 years 3 months (Stage A).

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Fig~ 2. Pretreatment study casts, 11 years 3 months,

are permitted their normal forward growth." in addition, he also found evidence of distal movement of the maxillary teeth. These clinical impressions were supported by cephalometric evaluations from Klein 5 in 1957, and Ricketts ~-in 1960. Both investigators found a significant reversal from normal growth tendency with A point moving backward when Class II malocclusions were treated with extraoral forces. These findings were to be confirmed and reconfirmed by other investigators throughout the next 25 years. Additional studies by Weislander 6 and Graber 7 not only substantiated these findings but also demonstrated that the results were stable, "showing minimal physiologic return after a 6 year follow-up of treatment changes,'6 These changes associated with a Class II correction by use of extraoral forces appear to be the result of a combination of orthopedic and orthodontic effects. 8-'3 By varying the intensity, direction, and duration of extraoral forces, these changes can be controlled.12 In the final analysis, it has been established that cervical extraoral forces can profoundly affect growth and development in such a way as to permanently alter the relationship of the maxilla and maxillary teeth to the mandible and mandibular teeth. These changes make a significant contribution in the correction of the Class II malocclusion and provide the framework for more harmonious facial balance.

Fig. 3. Pretreatment tracing, 11 years 3 months'.

CASE REPORT Diagnosis The patient had a Class II, Division 2 malocclusion with maxillary and mandibular crowding. Also associated with this malocclusion were an excessive overbite and overjet (Fig. l). HISTORY AND GENERAL CLINICAL PICTURE

The patient, a boy 11 years of age when first evaluated for orthodontic treatment, was in good health with no sig-

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Fig. 4. Facial and intraoral photographs at end of active treatment 15 years 4 months (Stage B).

Table I.

Summary

of cephalometric

measurements

Treatment stage Measurement

Norm

A

B

SNA SNB ANB SN-Go-Gn NPO-FI-I IMPA FMA APO (mm) A1 to NA angle AI to NA (ram) NB to NB angle N/3 to NB (ram) Interincisal angle Nasolabial angle

82 ° 80 ° 2o 32 ° 89 ° 90 ° 25 ° 1 22.0 ° 4.0 25.0 ° 4.0 131 ° 115 °

82 ° 76 ° 6° 34 ° 86 ° 95 ° 25 ° 2 19.5 ° 4 26.4 ° 5.5 128 ° 1130

81° 77.5 ° 3.5 ° 34.50 90 ° 93 ° 22 ° 3 20.4 ° 2.4 25.4 ° 5.6 131 ° 127°

nificant m e d i c a l problems. T h e dental history and examination s h o w e d several posterior r e s t o r a t i o n s , g o o d oral hygiene, and good gingival contours. T h e dental casts s h o w e d a C l a s s II m o l a r and canine relationship ( F i g . 2). T h e r e w a s a 5 m m m a n d i b u l a r tooths i z e / a r c h - l e n g t h discrepancy. A n overjet o f 7 m m and an overbite o f 100% with m a n d i b u l a r incisors that were imp i n g i n g on the palate were o b s e r v e d . In addition, the m a x -

80 ° 77 ° 3° 32.5 ° 91 ° 93 ° 19° 3 22 ° 3.9 22.5 ° 5.4 132.2 ° 130 °

illary midline w a s shifted 2 m m to the right. T h e initial facial photographs s h o w e d that the patient had a s o m e w h a t c o n v e x profile and that the lips were c o m p e t e n t in the relaxed position. A n analysis of the cephalometrie x-ray film disclosed a Class II, deep bite skeletal pattern as indicated by an A N B angle o f 6 ° (Fig. 3). The maxilla w a s well placed with an S N A angle of 82 ° as were the maxillary incisors, w h i c h w e r e

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Fig. 5. Final study casts, 15 years 4 months.

positioned 4 mm to NA (Table 1). The mandible was retrognathic, exhibiting an SNB angle of 76", but lower incisors were well placed relative to the mandible and the APO plane. The evaluation of the soft tissue indicated that the lips were in good position and the nasolabial angle tended to be obtuse. Additional radiographs showed all four third molars present. The general dental development appeared normal. CAUSE

This Class II malocclusion seemed to be caused by hereditary factors. The patient's mother also had a similar Class II malocclusion. There were no contributing medical problems or habits noted. GENERAL PLAN OF TREATMENT

The treatment objectives were to correct the skeletal and dental Class II relationships, relieve the crowding, and establish a more ideal overbite and overjet. A nonextraction treatment plan was formulated with a cervical headgear used to correct the skeletal discrepancy. A 0.022 x 0.028-inch edgewise appliance would be used to align all teeth and reduce the overbite and overjet. With this approach it was hoped that the incisors would remain in good position relative to the maxilla and mandible and thereby maintain good lip balance. It was believed that the nasolabial angle would be unfavorably affected by a retraction of the maxillary incisors. This type of case responds well to this nonextraction cervical headgear approach when good patient cooperation is combined with good growth potentials.

Fig. 6. Posttreatmenl tracing, 15 years 4 months. PROGRESS

Treatment progressed very well with excellent patient cooperation with respect to headgear. The patient was instructed to wear the cervical headgear 14 to 16 hours per day and was seen every 3 to 4 weeks to monitor his progress. Dental development, which was later than anticipated, delayed banding until February 1982. At that time teeth were aligned with a series of round wires. Space closure was accomplished with an 0.018 x 0.022-inch looped closing wire; final arch coordination and finishing details were completed with 0.019 × 0.025-inch rectangutar wires and medium 5 oz

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Fig. 7. Postretention study casts, 17 years 5 months.

Fig. 8. Posttreatment facial and intraoral photographs at 17 years 5 months (Stage C),

Class II elastics. After debanding, maxillary and mandibular removable retainers were inserted. The actual banded treatment time was 23 months and the patient continues to wear his retainers at night.

RESULTS ACHIEVED After active treatment, final records were obtained (Fig. 4), The dental casts showed a Class I occIusion (Fig. 5), The overbite and overjet were ideal and all maxillary crowding

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I Fig. 9. Postretention tracing, 17 years 5 months.

,J~

was eliminated, The mandibular left central incisor showed a tendency toward rotation. The facial profile showed a flattening of the upper lip as measured by an increase in the nasolabial angle (Fig. 6). The lips showed a mild retrusion relative to the nose and chin, which have undergone significant forward growth. The cephalometric analysis showed a reduction of the Class II skeletal discrepancy, reducing the ANB angle from 6 ° to 3.5 ° (Table I), Maxillary incisors were retracted siightly and mandibular incisors maintained 'their relative position to the mandible. The posttreatment panoral radiograph showed good axial inclinations of all teeth. In addition, there was no apical root resorption and third molars were present and in good positions.

15-4

I

,

-

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iLc tg N?

SECONDARY T R E A T M E N T

The patient continues to wear the removable retainers at night and is seen on a semiannual basis to monitor his dental development. After orthodontic treatment, he was involved in an accident that fractured maxillary right and left central incisors. These teeth were repaired with composite restorations by his dentist. FINAL EVALUATION

The postretention models show a good occlusal relationship (Fig. 7). The immediate posttreatment and postretention photographs and cephalometric x-ray films show significant amounts of facial growth with a stable dental relationship (Figs. 8 through 10). The nose and chin advanced during this time, making the lips appear more retrusive. A small mandibular incisor rotation was noted and continues to be monitored. A supracrestal fibrotomy may have been helpful in controlling this relapse. Superimpositions of lateral cephalometric tracings show marked skeletal mandibular change (Fig. 10, Table I). DISCUSSION

The final occlusion and facial form are the summation of a multitude of tissue responses. Some of these

Fig. 10. Superimposition of tracings. A, At 11 years 3 months (solid lines) and 15 years 4 months (dashed lines). B, At 15 years 4 months (solid lines) and 17 years 5 months (dashed

lines).

responses are the consequences of n o r m a l growth and development; others are responses to orthodontic intervention. The correction o f a Class II, Division 2 malocclusion in a growing patient has been presented. T h e use of cervical extraoral force has played an active role in altering these dental a n d skeletal malrelationships. It m u s t be emphasized that, a m o n g other factors, favorable growth a n d excellent patient cooperation were important, REFERENCES

I. Brodie AG. On the growth pattern of the human head, from the third manth to the eighth year of life. Am J Anat 1941;68:209. 2. Ricketts RM. The influence of otl:hodontie treatment on facial growth and development. Angle Orthod 1960;30:103-33. 3. Kloehn SJ. Orthodontics--force or persuasion. Angle Orthod 1953;23:56-65.

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4. Kloehn SJ. Evaluation of cervical anchorage force in treatment. Angle Orthod 1961;31:91-104. 5. Klein PL. An evaluation of cervical traction on the maxilla and the upper first permanent molar. Angle Orthod 1957;27:61. 6. Wieslander L. The effect of force on craniofacial development. AM J OR'r~OD 1974;65:531-8. 7. Graber TM. ExtraoraI force--facts and fallacies. AM J ORTHOD 1955;41:490-505. 8. Wieslander L, Buck DL. Physiologic recovery after cervical traction therapy. AM ]" ORTHOD 1974;66:294-301. 9. Mills CM, Holman RG, Graber TM. Heavy intermittent cervical traction in Class II treatment: a longitudinal cephalometric assessment. AM I OR'rr~OD 1978;74:361-79. 10. Gianelly AA, Valentini V. The role of "orthopedics" and orthodontics in the treatment of Class I1, Division 1 malocclusions. AM J ORTHOD 1976;69:668-78. 11. Baumrind S, Korn EL, Isaacson RJ, et al. Quantitative analysis

Am. J. Orthod. Dentofac. Orthop. May 1990 of the orthodontic and orthopedic effects of maxillary traction. AM I ORTHOD I983;84:384-98. 12. Armstrong MM. Controlling the magnitude, direction, and duration of extraoral force. AM J ORTHOD 1971;59:217-43. 13. "Poulton DR. A three-year survey of Class II malocclusions with and without headgear therapy. Angle Orthod 1964i34:181-93. 14. Greenspan RA. Reference charts for controlled extraoral force application to maxillary molars. AM J ORTHOD1970;58:486-9l. 15. Gianelly AA, Arena SA, Bernstein L. A comparison of Class II treatulent changes noted with the light wire, edgewise, and Ffiinkel appliances. AM J ORTHOD 1984;86:269-71. Reprint requests to: Dr. Steven A. Hershcopf 435 Buckland Road South Windsor, CT 06074