Class II Patient Therapy Requiring Minimum Compliance

By Larry W. White, DDS, MSD

---

An adolescent female patient (Figs. 1 and 2) presented with a bilateral Class II malocclusion, maxillary and mandibular arch length discrepancies, a midline discrepancy, excessive overjet and overbite, and an excessive A-B discrepancy of 9 mm. I prefer using Natural Head Posture,¹ rather than SNA, SNB and the Frankfort Horizontal.² Still, the maxillary incisor had an ideal position in relation to the A-line,³ and the upper lip had an ideal position and measurement according to Holdaway’s subnasale line,⁴ while the mandibular incisors were retruded. Clearly, one would not want to retract the maxillary dentition and risk streamlining an otherwise ideal upper lip.

Several options could have been chosen to correct this malocclusion, but the one selected did not require Class II correctors or Class II elastics. Rather, a decision was made to correct the malocclusion using nothing more than brackets, wires and the application of judicious interproximal enamel reduction (IER) of the mandibular incisors and, principally, a slightly long 0.016 x 0.022 SS utility arch.

Once alignment occurred with IER and round NiTi wires, the utility arch was made to advance and simultaneously intrude the mandibular anterior teeth, as suggested by the visualized treatment objective (Figs. 3 and 4).⁵

Small created spaces can be seen in Fig. 4, along with bite opening, partial correction of the Class II posterior occlusion and correction of the overbite and overjet. Fig. 5 shows the malocclusion just prior to removal of the appliances. No intermaxillary elastics or mechanisms were used as therapy with the patient. Once a Class I occlusion was achieved in the canines, the premolars were bonded and protracted distally with compressed coils and mesially with power chains using the biomechanics suggested by Mulligan.⁶

The mandibular molars were protracted using differential moments and the rest of the arch as anchorage. Final SS arch wires were inserted in both arches, and treatment was completed (Fig. 6).

Figs. 7 and 8 provide cephalometric tracings of the therapy. Fig. 7 shows how, when aligned with the Sella-Nasion line, growth provided some assistance in the correction as the mandible outgrew the maxilla, consistent with the work of Mastorakas.⁷ Fig. 8 displays how the mandibular teeth responded to therapy in relation to the maxilla. The maxillary incisors were moved forward slightly to provide more overjet, and the mandibular incisors protracted and intruded to allow a proper overjet and overbite.

This successful Class II patient treatment using only arch wires, brackets and biomechanics, first introduced by Burstone,⁸ offers clinicians an alternative approach to the usual Class II techniques. Still, when one examines the results of this protraction of the mandibular dentition, it is similar to that which clinicians receive with intermaxillary mechanics⁹ but without the problem of patient compliance and extrusion and lingual tipping of maxillary incisors. Additionally, the face suffered no untoward effects in this case, and the patient was not forced to contend with onerous and expensive appliances that patients often break, remove or, in the case of elastics, completely ignore.

This is not a universal approach for Class II therapy, and patients require several features to make the method succeed, including:

• A favorable profile; a bimaxillary protrusive profile would disqualify them and probably require the removal of teeth
• A favorable position for the maxillary incisor, as shown in the findings of Holdaway,¹⁰ Alvarez,¹¹ Bass,¹² and Creekmore,¹³ among others.
• A < 7mm overjet, as anything greater would likely require a more robust Class II intermaxillary appliance; the mandibular incisors respond best when they are retrusive and the overbite is deep.
• Sufficient overjet or the type of overbite and overjet that allows the creation of adequate overjet by advancing the maxillary incisors and/or intrusion and protraction of the mandibular anterior teeth.

Large arch length discrepancies could present limitations for this method of correcting Class II malocclusions. Clinicians can make the decision to use the technique by an accurate clinical assessment or, better yet, by setting a static visualized treatment objective, which will give them a more accurate positional assessment of the teeth in relation to the profile. This approach works unusually well with premolar extraction patients when, upon space closure, the bite deepens and the canines have an end-on relationship, rather than a firm Class I. It offers a reasonable alternative to the sole reliance on osseous points and the mandibular incisor on the cephalometric tracing for diagnosis and treatment planning.

While this method may seem to be a reproach to earlier pioneers, such as Tweed, Steiner, Williams, Ricketts and others, I do not find this to be the case. Dr. Bill Parker, speaking about his early resident experience in the 1940s in one of the best orthodontic departments in America, said neither faculty nor residents really understood what they were doing when they placed bands, brackets and wires in patients’ mouths. Sometimes they worked well, and other times they didn’t, but no one entirely knew why. Tweed was the first orthodontist to rescue colleagues from the dilemma, giving them a target, a method for achieving it, and a way to measure whether they had arrived at the target. Although the approach was limited, it was a significant improvement compared to that of most of Tweed’s contemporaries.

Although Casko and Shepherd,¹⁴ along with McNamara,¹⁵ have amply demonstrated that patients with Class I occlusions and favorable faces demonstrate wide ranges in positions of maxillary and mandibular incisors, along with maxillary and mandibular jaw relationships, clinicians attached to using upright mandibular incisors as a goal may find the approach demonstrated in this case troubling. However, the therapeutic strategy offers signal advantages, including simplicity, patient acceptance and ease of adjustment, that more common techniques lack. Based on the evidence available, insisting on the mandibular incisor as the nexus of diagnosis and treatment planning without considering the soft tissue and maxillary incisor position unnecessarily handicaps orthodontic clinicians.

---

REFERENCES:

1. Moorrees, C.F.A., and M.R. Keane. “Natural head posture, a basic consideration in the interpretation of cephalometric radiographs.” Am J Phys Anthropol, 1958 16(2): 213–234; Michiels, L.Y., and L.P. Tourne. “Nasion true vertical: a proposed method for testing the clinical validity of cephalometric measurements applied to a new cephalometric reference line.” Int J Adult Orthodon Orthognath, 1990 5(1): 43–52; Lundstrom, F.L. “A Natural head posture as a basis for analysis.” Am J Orthod Dentofacial Orthop, 1992 101(3): 244–247; Cooke, M.S., and S.H. Wei. “The reproducibility of natural head posture: a methodological study.” Am J Orthod Dentofacial Orthop, 1988 93(4): 280–288; and Cooke, M.S., and S.H. Wei. “A summary five-factor cephalometric analysis based on natural head posture and the true horizontal.” Am J Orthod Dentofacial Orthop, 1988 93(3): 213–223. ↩︎
2. Reidel, R. “The relation of maxillary structures to cranium in malocclusion and in normal occlusion.” Angle Orthod, 1952 22(3): 284–292; and Steiner, C.C. “The use of cephalometrics as an aid to planning and assessing orthodontic treatment: Report of a case.” Am J Orthod, 1960 46(10): 721–735. ↩︎
3. Alvarez, A.T. “The A line: a new guide for diagnostic and treatment planning.” J Clin Orthod, 2001 35(9): 556–569. ↩︎
4. Holdaway, R.A. “A soft-tissue cephalometric analysis and its use in orthodontic treatment planning. Part 1.” Am J Orthod, 1983 84(1): 1–28; and Holdaway, R.A. “A soft-tissue cephalometric analysis and is use in orthodontic treatment planning. Part II.” Am J Orthod, 1984 85(4): 279–293. ↩︎
5. Holdaway, R.A. “A soft-tissue cephalometric analysis and is use in orthodontic treatment planning. Part II.” Am J Orthod, 1984 85(4): 279–293. ↩︎
6. Mulligan, T.F. Common Sense Mechanics, Edition II. 2009, CSM Publishing: Phoenix, Ariz., 311–312. ↩︎
7. Mastorakas, W.L. Components of Class II malocclusion in children age 12–14. 1983, St. Louis University School of Dentistry: St. Louis, MO. ↩︎
8. Burstone, C.J. “The Biomechanics of Tooth Movement.” In: Kraus, B.S., and R.A. Riedel (eds), Vistas in Orthodontics. 1962, Lea & Febiger: Philadelphia, 197– 213; Burstone, C.J., and K. Choy. The Biomechanical Foundation of Clinical Orthodontics. 2015, Quintessence Publishing Co: Chicago; and Burstone, C.J., and M.R. Marcotte. Problem Solving in Orthodontics: Goal-Oriented Treatment Strategies. 2000, Quintessence Publishing Co: Chicago. ↩︎
9. Cope, J.B., P.H. Buschang, D.D. Cope, J. Parker, and H.O. Blackwood III. Quantitative evaluation of craniofacial changes with Jasper Jumper therapy, Angle Orthod, 1994 64(2): 113–122; Jones, G., P.H. Buschang, K.B. Kim, and D.R. Oliver. “Class II non-extraction patients treated with the Forsus Fatigue Resistant Device versus intermaxillary elastics.” Angle Orthod, 2008 78 (2): 332–338; de Castro Alvares, J.C., R.H. Cançado, F.P. Valarelli, K.M.S. de Freitas, and C.Z. Angheben. “Class II malocclusion treatment with the Herbst appliance in patients after the growth peak.” Dental Press J Orthod, 2013 18(5): 38–45; Coelho Filho, C.M. “Mandibular protraction appliance IV.” J Clin Orthod, 2001 35(1): 18 24; DeVin- cenzo, J.P. “Changes in mandibular length before, during, and after successful orthopedic correction of Class II malocclusions, using a functional appliance.” Am J Orthod Dentofacial Orthop, 1991 99(3): 241–257; Creekmore, T.D., and L.J. Radney. “Frankel appliance therapy: orthopedic or orthodontic? Am J Orthod, 1983 83(2): 89–108; and Eckhart, J.E., and L.W. White. “Class II Therapy with the Mandibular Anterior Repositioning Appliance.” World J Orthod, 2003 4(2): 1–10. ↩︎
10. Holdaway, R.A. “A soft-tissue cephalometric analysis and is use in orthodontic treatment planning. Part II.” Am J Orthod, 1984 85(4): 279–293. ↩︎
11. Alvarez, A.T. “The A line: a new guide for diagnostic and treatment planning.” J Clin Orthod, 2001 35(9): 556–569. ↩︎
12. Bass, N.M. “The aesthetic analysis of the face.” Eur J Orthod, 1991 13(5): 343–350; and Bass, N.M. “Measurement of the profile angle and the aesthetic analysis of the facial profile.” J Orthod, 2003 30(1): 3–9. ↩︎
13. Creekmore, T.D. “Where Teeth Should Be Positioned in the Face and Jaws and How to Get Them There.” J Clin Orthod, 1997 31(9): 586–608. ↩︎
14. Casko, J.S., and Shepherd, W.B. “Dental and skeletal variation within the range of normal.” Angle Orthod, 1984 54(1): 5–17. ↩︎
15. McNamara Jr., J.A., and E. Ellis III. “Cephalometric analysis of untreated adults with ideal facial and occlusal relationships.” Int J Adult Orthodon Orthognath Surg, 1988 3(4): 221–231. ↩︎