Ortodontia

As we see more adults entering comprehensive orthodontic treatment, we must be more attuned to the implications of periodontal issues. In this updated chapter, Robert Vanarsdall, Ignacio Blasi and Antonino Secchi review periodontal issues that impact orthodontic tooth movement. They describe periodontal "high risk" factors, mucogingival considerations, and problems with ectopic as well as ankylosed teeth. A new section on alveolar decortication and augmentation grafting has been added to address the increased use of these procedures designed to develop the alveolar housing and potentially increase the speed of tooth movement. Excellent clinical examples are pictured throughout the chapter.

Minimally and Non-Invasive Approaches to Accelerate Tooth Movement:
Micro-osteoperforations. Patients are always attracted to decreasing the time it takes to complete orthodontic treatment. Recent advances in the understating of bone biology have been applied to a number of adjunctive techniques that in certain situations may reduce the time for certain tooth movements. In this new chapter, Ignacio Blasi looks at the use of micro-osteoperforations and the ability of these perforations to increase bone turnover rates, providing for increased speed of tooth movement. Studies have been done that demonstrate a localized positive effect on the speed of tooth movement.
Mechanical Vibration. Dubravko Pavlin presents information on the influence of low level mechanical vibration on orthodontic treatment, a technique borrowed from orthopedic colleagues. Some of the animal and human studies have reported increased rates of tooth movement and an ability to reduce pain perception when low level vibration therapy is used. Still other studies report no clinical effectiveness. While the jury is still out on this technique, clinical and basic science research into adjuncts that can influence biologic factors, are likely to bear fruit in the future.

Rapid palatal expansion (RPE) has been used primarily to treat dental crossbites or for space gaining to prevent extractions with little or no attempt made to coordinate or normalize the transverse skeletal pattern. Traditionally, maxillary orthopedics has been performed using the dental units only as anchorage (e.g., Hyrax or Haas appliances). Dental anchorage not only has created limited skeletal orthopedic change, but also can cause significant adverse periodontal outcomes and unstable side effects. There is a clear correlation between buccal tooth movement and gingival recession and bone dehiscences. These adverse periodontal responses with RPE indicate the importance of early treatment. The beneficial periodontal effects of transverse skeletal correction have been a primary focus of our research for the past 35 to 40 years. We have emphasized the importance of correcting transverse skeletal discrepancy to: 1) prevent periodontal problems; 2) achieve greater dental and skeletal stability; 3) improve dentofacial esthetics by eliminating or improving buccal corridors; and 4) improve airway resistance. When it may be critical to save the natural dentition, we do not want to introduce adverse dental/skeletal changes for adolescent patients and/or patients with advanced periodontal disease. New advances in skeletal anchorage should permit orthopedic change without adverse dental changes by applying force directly to the maxillary bone; an innovative technique to maximize the skeletal maxillary changes in the transverse dimension is explained in this chapter. Furthermore, diagnosis of the transverse dimension—the use of cone-beam computed tomography (CBCT) for 3D evaluation of skeletal changes, the benefits of the skeletal transverse changes of the whole maxillofacial complex and its periodontal response, the changes in airway and non surgical RPE with bone-anchored appliances utilizing temporary anchorage devices (TADs)—is described and discussed.

Introduction: The effect of the maxillary expander on the inferior third of the face may be conditioned by the type of expander when done with an occlusally bonded acrilic covering or on conventional bands.
Objective: The purpose of this retrospective study was to compare the effects of expander design on the vertical plane using a) a banded Haas expander and, b) a Haas expander with acrilic covering, in the Steiner mandibular plane.
Materials and Methods: Initial (before treatment) and final (months after expander removal) lateral cephalometric x-rays of 20 patients with disjunction were retrospectively compared: ten patients with Haas expanders bonded with acrilic covering and ten patients with banded Haas expanders. The reference plane employed was S-Na. The mandibular plane was Go-Gn anatomic.
Results: Significant differences existed between both groups before initiating treatment. It was observed in the group with banded Haas expanders that the mandibular plane of 5 subjects remained unchanged while increasing in the other 5 subjects. The mean initial mandibular plane was 34.7º, while the final mean was 35.55º. No significant differences existed.
With respect to the group with Haas expanders with acrilic covering, the mandibular plane did not change in four subjects, while decreasing 5 others and increasing by 4º in one individual. Average initial mandibular plane was 39.25º; The final average was 38.85º. There were, similarly no significant differences present in this group.
Conclusions: Rapid Palatal Expansions (RPE) conducted with banded Haas expanders remains unchanged or increase lightly the mandibular plane. On the contrary, those conducted with acrilic covered expanders tend to either maintain or decrease the mandibular plane angle. The acrilic covered expander appears to provide some control over vertical dimension, thus indicating its more appropriate use in patients with increased vertical dimension such as dolichofacial patterns. Conclusions from this study are based on results obtained from a retrospective study in which samples were not randomly chosen. We think that further prospective research studies on the effect of maxilliary expansion on facial pattern should be done.