Orthodontics in the Vertical Dimension

A Case-Based Review

Thomas E. Southard, Steven D. Marshall, Laura L. Bonner

• Publisher: Wiley-Blackwell
• Year: 2015
• ISBN:
  9781118925201
• Edition: 1
• Topic: Medicine
• Subtopic: Orthodontics

This case-based clinical text is an exhaustive review of orthodontic problems in the vertical dimension, with evidence-based guidelines for successful diagnosis and treatment. A total of 21 cases address dental deep bites, skeletal deep bites, dental open bites, skeletal open bites, and posterior open bites. Each case includes pretreatment, interim, and posttreatment orthodontic records, as well as references to provide a solid evidence base for decision making. Written with a clinical focus, Orthodontics in the Vertical Dimension is ideal for the practicing orthodontist and makes an excellent resource for residents in pursuit of board certification.

Key Features

• Detailed case-based scenarios for treatment of the spectrum of open bites and deep bites

• Cases presented in question and answer format to encourage thought

• 2500 clinical photographs and illustrations.

"This is a great textbook, and I will use it in my classes. Highly organized and elaborately illustrated, the authors' work is inspired by problem-based learning and stimulates cognitive processes by encouraging critical thinking. Their text deserves a 'must read' category for orthodontic professionals of all ages."

Dr. Jeryl D. English DDS, MS, Chairman and Graduate Program Director, Department of Orthodontics, The University of Texas Health Science Center at Houston

"A terrific book for students of orthodontics and dentofacial orthopedics, covering the vertical dimension and much more. A wide range of cases are presented, treatment plans are realistic, and the authors openly discuss complications encountered during treatment."

Dr. Greg J. Huang, DMD, MSD, MPH Professor and Chair Department of Orthodontics, The University of Washington School of Dentistry

"This comprehensive text prepares the reader in the context of a mini-residency with a question answer teaching style. Resident and experienced orthodontists can match their cases with fully worked up patients and alternative treatment options. Well written."

Dr. Katherine L. Vig, BDS, MS, FDS, D.Orth Professor Emeritus and Former Head of Orthodontics, The Ohio State University College of Dentistry

CHAPTER 1
Foundations

The Spectrum of Vertical

Q: Emily is a 20-year-old who presents to you for treatment (Figure 1.1). Compare her soft tissue midface height to her soft tissue lower anterior facial height (LAFH). What do you observe?

Figure 1.1 (a, b) Emily’s facial photographs. (c, d) Soft tissue midface height (vertical distance from supraorbital ridges/soft tissue Glabella to Subnasale) is compared to LAFH (vertical distance from Subnasale to soft tissue Menton). Abbreviations used in this book are defined in the Appendix.

A: Emily’s soft tissue proportions are nearly ideal. Her soft tissue midface height is equal to her soft tissue LAFH. [1, 2] Also, the distance from Subnasale to Stomion is approximately one-half of the distance from Stomion to soft tissue Menton. She exhibits lip competence without either an interlabial gap (ILG) or an overclosed appearance.

Q: Next, evaluate her vertical skeletal and dental features using her cephalometric tracing (Figure 1.2). What do you observe?

Figure 1.2 (a) Emily’s lateral cephalometric tracing. (b) Skeletal TAFH is the distance Nasion–Menton. Skeletal LAFH is the distance measured from Menton along a Nasion–Menton line to a point where ANS projects perpendicularly to the Nasion–Menton line. A primer on the determination of facial height and other cephalometric measurements used in this book can be found in the Appendix.

A: The (percentage) skeletal LAFH is expressed as a proportion of (linear) skeletal LAFH to (linear) skeletal TAFH (total anterior facial height). TAFH is the distance Nasion–Menton. LAFH is the distance measured from Menton along a Nasion–Menton line to a point where ANS projects perpendicularly to the Nasion–Menton line. For Emily, the LAFH/TAFH ratio (expressed as a percentage) is 54%. Ideal LAFH/TAFH is 55%, and one standard deviation difference from ideal is approximately 2% [3]. So, Emily’s LAFH/TAFH is normal. In terms of mandibular plane (MP) angles, her FMA is normal (26°; ideal is 25°) and SNMP is normal (30°; ideal is 32°). Her maxillary first molar root apices are located below the palatal plane, a feature generally found in patients with vertical maxillary excess. Finally, the maxillary central incisor tip extends below the upper lip by approximately 4 mm (ideal 2–4 mm) [4]. A primer on the determination of facial height and other cephalometric parameters used in this book can be found in the Appendix.

Q: A number of Emily’s skeletal and dental features were described as normal, but not ideal. Should not the terms normal and ideal be synonymous? In other words, if the ideal (average) FMA is 25°, should not this exact value be considered normal and all other FMA values considered abnormal?

A: No. “Normal” constitutes a range of values and not one specific number. That is why we say, “within the range of normal,” or WRN. In other words, an FMA of 25° is normal but so can FMAs of 26°, 27°, 28°, 24°, 23°, and 22° be considered WRN. The same can be said for LAFH/TAFH proportions, ANB values, FMIA values, and so forth. Ideal can be considered one specific value, for instance, the average value measured from a population, but normal is a range—not a number. Think of it this way, there exists a broad range of what we consider beautiful human faces, and normal human faces cover an even broader range. A discussion of “normal” cephalometric values can be found in the Appendix.

Q: Evaluate Emily’s vertical dental features, as seen intraorally (Figure 1.3a). What do you observe?

A: Overall, she presents with normal overbite (10–20% vertical overlap of her mandibular incisors by her maxillary central incisors measured in centric occlusion, Figure 1.3b). Variation in overbite is illustrated in Figure 1.4, which ranges from excessive vertical overlap (deep OB, Figure 1.4 left) to an absence of vertical overlap (open bite, Figure 1.4 right). Emily’s maxillary right lateral incisor (Figure 1.3a) exhibits inadequate vertical overlap with her mandibular right lateral incisor—resulting in dark incisal embrasures. Her maxillary central incisor gingival margins are at the same level (ideal), her right and left maxillary lateral incisor gingival margins are about even but stepped down slightly co...