Pacific Coast Society of Orthodontists Bulletin Fall 2013 - (Page 11)

The Class II, Division 2 Malocclusion Part II By Ib Leth Nielsen, DDS, MSc Ed.: Dr. Nielsen brings a clinically useful understanding to treatment planning for a Class II div. 2. Clinicians can surely benefit from taking another look at the landmark growth study by Björk, where he followed mandibular growth over many years with implants serving as the superimposition landmarks. — G.N. I n a previous article (Summer 2013 PCSO Bulletin) on the topic of the class II, division 2 malocclusion, we discussed the etiological factors that lead to the development of this malocclusion. These factors include growth rotation during the active growth phase of the maxilla and mandible, as well as the soft tissues surrounding the dentition (in particular the lower lip). The anterior occlusion that is achieved during the eruption of the front teeth also plays a large role in a development that may result in a deep overbite. It is important for the clinician to be able to anticipate this development from an early age so that he or she can prevent the situation from getting worse over time. Anticipating this development allows one to choose the most practical time for treatment. FORWARD JAW ROtAtiOn AnD OCCLuSiOn Mandibular Growth Rotation As long ago as 1969, Björk explained that the mandible does not just grow linearly, as seen in 2 the Broadbent-Bolton Atlas ; it also rotates during growth, and under certain circumstances this may result in a deep overbite.3 Björk also explained that when the anterior teeth reach a good occlusion, the mandibular growth pattern does not cause an increase in overbite, but remains stable. An example of this situation is seen in Björk’s Case 3, as illustrated in Figure 1.1. The general facial growth pattern is analyzed by superimposing on stable structures in the cranial base. Growth of the maxilla and mandible is analyzed in this example by superimposition on the maxillary and mandibular implant lines, respectively. The growth period shown is a six-year span around puberty, the most active growth period of the jaws. The superimposition on the cranial base shows downward and forward Figure 1. Six years of general facial, maxillary and mandibular growth in a young female patient. The occlusion in this subject remained unchanged despite pronounced mandibular rotation. From Björk and Skieller, 1972.1 FALL 2013 • PCSO BuLLetin 11

Table of Contents for the Digital Edition of Pacific Coast Society of Orthodontists Bulletin Fall 2013

An Editor's Journey
A Sense of Belonging
To Meet Member Needs, You Have to Know Members
Stronger, More Efficient, More Focused
Service Behavior
Class II, Division 2 Malocclusions, Part II
Dr. Terry McDonald Interviews Dr. Douglas Klein
Mark Douglas, DDS
Vincent G. Kokich, Sr., DDS, MSD
Elastic Wear Tips
AAOF
PCSO Business
Component
PCSO at a Glance
Case Report Pre-Treatment
Case Report Post-Treatment

Pacific Coast Society of Orthodontists Bulletin Fall 2013