CASE REPORT

Class II, Division I malocclusion treated with molar distalization therapy

Joydeep Ghosh, BDS, MS," and Ram S. Nanda, DDS, MS, PhD b Oklahoma City, Okla.

A case report of an 11-year-old black girl with a Class II, Division 1 malocclusion is presented. There was associated lip incompetence and excessive display of gingiva on smiling. Nonextraction treatment was undertaken with distalization of maxillary molars to correct the Class II relationship. [This case was presented at the annual session of the American Association of Orthodontists held in Orlando, 1994. This was part of the University of Oklahoma, Department of Orthodontics participation in the display of patients treated by graduate students sponsored by the College of Diplomates, American Board of Orthodontics.] (Am J Orthod Dentofac Orthop 1996;110:672-7.)

CASE REPORT

The case of a girl with a Class II, Division 1 malocclu- sion is presented. The results of nonextraction orthodontic mechanotherapy resolved the problem esthetically, as well as functionally.

HISTORY AND GENERAL CLINICAL PICTURE

The patient initially came to the orthodontic department as a healthy, black, premenarcheal girl with a chief complaint of "my front teeth stick out" (Fig. 1). The patient 's cbxono-

From the Department of Orthodontics, University of Oklahoma. "Research Associate and Assistant Professor. bProfessor and Chair. Reprint requests to: Dr. Joydeep Ghosh, Department of Orthodontics, Univer- sity of Oklahomha College of Dentistry, 1001 S.L. Young Blvd., Oklahoma City, OK 73190. Copyright �9 1996 by the American Association of Orthodontists. 0989-5406/96/$5.00 + 0 8/4/64374

logic age was 11 years 1 month and skeletal age was also the same. She was 58 inches tall (40th percentile) and weighed 73 pounds (25th percentile). Her medical history was non- contributory, and her tonsils and adenoids were present. Her parents reported a thumb sucking habit between the ages of 2 and 9 years.

DIAGNOSIS

The patient had a Class II, Division 1 malocclusion in the permanent dentition (Figs. 2 and 3). She had a buccal crossbite of the maxillary right first premolar. The maxillary and mandibular midlines were coincident with the facial midline. She has a overjet of +11.0 mm and a deep, impinging overbite of 100%. Her occlusal guidance on both right and left lateral excursions was group function on the canines and premolars. An examination of the temporoman- dibular joints revealed no abnormalities; however, the patient reported an occasional popping in both joints on wide opening.

672

Fig. 1. Initial extraoral photographs.

American Journal of Orthodontics and Dentofacial Orthopedics Ghosh and Nanda 673 Volume 110, No, 6

Fig. 2. Initial intraoral photographs.

The cephalometric analysis substantiated the Class II skeletal relationship with an ANB angle of +8 ~ (Fig. 4, Table I). The Frankfort-mandibular plane angle was 26 ~ along with a 54% lower anterior face height. The maxillary incisors were proclined and procumbent. The maxillary arch was symmetrical and ovoid with 6 mm spacing, whereas the mandibular arch was symmetrical and ovoid with 2 mm spacing.

The soft tissue profile was posterior divergent and con- vex. The incision to upper lip stomion distance was 4 mm and she exposed 5 mm of gingiva on a full smile. Because of the relationship of the maxillary and mandibular incisors, the lips were incompetent with a 3 mm interlabial gap on repose with the lower lip positioned behind the maxillary incisors. The nasolabial and mentolabial angles were acute at 66 ~ and 60 ~ respectively.

Her periodontal condition was good, though the area lingual to the maxillary incisors was at risk of deterior- ation because of the deep, impinging overbite. Exami- nation of the panoramic radiograph showed no abnormal- ities.

Table 1. S u m m a ~ ' o f

cephalometric measurements

Measurement

I CA = 11-1 [ CA = 14-5

I 31 Mar 1994 Norm 31 Jan, 1991

S N A 84.5 ~ 85 .0 ~ 80 .0~

S N B 79.5 ~ 77 .0 ~ 75 .0

A N B + 5 .0 ~ + 8 . 0 ~ +5-0~

F H - N - P O 87-0 ~ 86 ,0 ~ 84-0~

F M A 25 ,0 ~ 26 .0 ~ 28 .0 '~

S N - G o - G n 34 .0 ~ 34 ,0 ~ 37`0o

O P - S N 18,0 ~ 16.0 ~ 20 ,0 ~

U p p e r i nc i so r to N A +7.5 m m +9 .0 m m + 3 ,0 m m

U p p e r inc i so r to N A 24 .0 ~ 33 ,0 ~ 22-0~'

L o w e r inc i so r to N B + 10.0 turn +7 m m + 8 m m

L o w e r inc i so r to N B 37 ,0 ~ 28 .0 ~ 33-0~

L o w e r inc i so r to A - P o +10 .5 m m +1.5 m m + 3 .0 m m

I MPA 100.0 ~ 97 ,0 ~ 102 ~

F M I A 5 0 , 0 ~ 57 .0 ~ 50.00

ln te r inc i sa l ang l e 114.0 ~ 112.0" 120.0 ~

U p p e r l ip to E- l ine + 2 .0 rnm + 6 .0 m m - 2 . 0 m m

L o w e r l ip to E- l ine 0 .0 m m +8 .0 m m + 1 .0 m m

N a s o l a b i a l ang l e 66 .0 ~ 87 .0 ~

M e n t o l a b i a l ang l e 60 .0 ~ 117.0 ~

674 Ghosh and Nanda American Journal of Orthodontics and Dentofacial Orthopedics December 1996

Fig. 3. Initial models,

)

Fig. 4. Initial cephalometric tracing.

PLAN OF TREATMENT

Because a fuller, slightly protrusive profile is more desirable for black persons, 16 a nonextraction treatment plan was developed that consisted of the following:

1. Distalize the maxillary molars to correct the Class II relationship. After distalization of the molars, sequen- tially retract the premolars, canines, and incisors to correct the overjet.

2. Correct the deep overbite. 3. Achieve a stable, functional occlusion with a pleasing

smile and lip competence.

TREATMENT PROGRESS

Treatment was initiated by banding the maxillary first molars and second premolars with an 0.018 • preadjusted bracket system and placement of a Nance hold- ing arch between the maxillary second premolar bands. The

American Journal of Orthodontics and Dentofacial Orthopedics Ghosh and Nanda 675 Volume 110, No. 6

Fig. 5. Final extraoral photographs.

Fig. 6. Final intraoral photographs.

maxillary first molars were distalized with the use of 0.016- inch stainless steel arch wire segments that spanned between the premolar and the molar on each side and the use of nitinol compressed coil springs that delivered a near con-

stant /brce of approximately 150 gm. A cervical-pull face- bow headgear was also used for distalization and root uprighting. Within 4 months, the molars were distalized to a super-Class I relationship, whereas, the second pre-

676 Ghosh and Nanda American Journal of Orthodontics and Dentofacial Orthopedics December 1996

Fig. 7. Final models.

Fig, 8. Final cephalometric tracing.

molars moved mesially 2 mm. The Nance holding arch was removed from the second premolars and subsequently placed on the maxillary first molars to stabilize their po- sition.

The second and first premolars were also allowed to drift distally for a period of 5 months, and posterior spaces were conso!idated with a light elastomeric chain. The ca- nines were then retracted with the light chain. Once the premolars and canines were fully retracted, the inci- sors were retracted en masse with elastics between the molar and a hook bent into the 0.016 • 0.022-inch stain- less steel arch wire. The face-bow headgear was worn for the major part of the treatment by the patient to maximize anchorage control. Appliances were placed in the mandibular arch 17 months into treatment, and alignment and levelling were accomplished through sequential in- creases in arch wire size from a 0.0175-inch multistrand stainless steel arch wire to a 0.017 x0.025- inch stainless steel arch wire.

The patient was cooperative and the appliances were removed 36 months after initiation of treatment. One day after debonding, a maxillary Hawley retainer and a mandibu- lar removable canine-to-canine spring retainer were deliv- ered. The patient was instructed to wear the retainers full- time for 6 months, at which time a decision for reducing the time of wear would be made.

American Journal of Orthodontics and Dentofacial Orthopedics Ghosh and Nanda 677 Volume 110, No. 6

!Fj

�9 '" ~ ! i

Fig. 9. Superimposition tracings of initial and final lateral cephalometric tracings.

TREATMENT RESULTS

The photographs show a much improved profile (Fig. 5). The lips have been retracted about 7 mm, with respect to the E-lines, and are competent. The smile was improved, with less amounts of gingiva exposed.

An excellent overbite and overjet relationship of teeth was achieved (Figs. 6, 7, and 8). The correction of the overbite improved the condition of the palatal mucosa. Class I canine relationships with occlusal guidance during lateral excursions in group function on the canines and first premolars, without balancing side interferences were present. There were significant amounts of vertical dental and skeletal changes during the treatment period, as seen on the cephalometric superimpositions (Fig. 9). There was no change in the intercanine width in the maxilla and an increase of 0.5 mm in the mandible, whereas, the intermolar width increased by 1 mm in the maxilla and decreased 0.5 mm in the mandible.

The dental and periodontal health was good and the radiographic examination indicated satisfactory root paralleling without any loss of tissue.

FINAL EVALUATION

This Class II, Division 1 malocclusion was suc- cessfully treated with nonextraction therapy. The cor- rection of the malocclusion was realized with a notable

improvement in patient's self-esteem. The following conclusions may be drawn from consideration of this case report:

1. The timing of treatment was important to the success of the nonextraction treatment plan be- cause of the considerations of growth, patient compliance, and stage of eruption of maxillary second molars.

2. An extraction-based therapeutic approach with overretraction of anterior teeth, disregarding the fuller lip profile that is more acceptable for black persons, could have adversely affected the facial balance and harmony.

We would like to thank Drs. Bollenbach and Boekenoo- gen for their assistance.

REFERENCES

1. AItemus LA. A comparison of cephalometric relationships. Angle O,nhod 1960;30:223-

40, 2 Altemus LA. Comparative integumental relationships. Angle Orthod 1963:33:217-21. 3. Sushner N. A photographic study of the soft tissue profile of the Negro population. Am

] Orthod 1977:72:373-g5. 4. Drummond RA. A determination of cephalometric ,orms for the Negro race, Am J

Orthod 1982; 54:670-82. 5. Connor AM, Moshiri E O~hognathic surgery norms for American black patients. Am J

Orthod 1985;87(2): 119-34. 6. Farrow AL, Zarrinnia K, Azizi K. Bimaxillary protrusion in black Americans-an esthetic

evaluation and the treatment considerations. Am J Orthod Dentofac Orthop 1993;104:

240-50.