1
Foundations
General Principles
The problems you will face in treating early malocclusions vary widely and are ever‐changing. However, the principles presented in this section are enduring and will serve as your foundation for dealing with those problems.
- Q: What is early orthodontic treatment?
A: Early orthodontic treatment (early limited treatment, early interceptive treatment, or Phase I treatment) is the treatment provided during the primary or mixed dentition stages of dental development. Comprehensive orthodontic treatment (Phase II treatment) is provided in the adult dentition.
- Q: What is the goal of early orthodontic treatment?
A: The goal is to correct developing problems to get the patient back on track (back to normal) for their stage of development. This includes treatment to prevent complications, reduce future comprehensive treatment complexity, and reduce/eliminate unknowns.
- Q: Can you provide examples of early treatment to prevent complications or reduce future treatment complexity?
A: Early treatment can prevent root resorption or tooth impaction in some cases of ectopic tooth eruption. Early treatment can eliminate the need for permanent tooth extractions or orthognathic surgery in some cases of skeletal discrepancies.
- Q: Can you provide examples of unknowns which can be reduced/eliminated with early treatment? Why are reducing/eliminating unknowns important?
A: Examples of unknowns include:
- Magnitude and direction of future jaw growth
- Undetected CR‐CO shifts
- Patient cooperation with headgears, functional appliances, elastics, hygiene, etc.
- Ectopic tooth eruption
Reducing/eliminating unknowns enables the orthodontist to more effectively plan final treatment and achieve desired outcomes. Let’s consider one quick example. Assume that a child presents to you in the late mixed dentition with a bilateral Class II molar relationship of 4 mm. Further assume that, after careful analysis, you settle upon two treatment options – either Class II orthopedics or extraction of maxillary first premolars (masking the underlying skeletal discrepancy). It would be prudent to reduce unknowns first by attempting Class II orthopedics and monitor the response you get, before you decide on a final treatment plan (finish with orthopedics or treat irreversibly with extractions).
Key principle: After you have defined the patient problems you hope to address, always force yourself to answer the following questions: What unknowns are present in treating this patient, and what unknowns should I eliminate before I define my final treatment plan or do something irreversible?
Always explain unknowns to patients and parents. Informing them early of uncertainties in your plan will foster a smooth transition if you later need to modify your treatment plan due to unanticipated growth or treatment response. Always reduce/eliminate unknowns before committing to irreversible treatment. To do otherwise is to gamble on your patient’s outcome. Finally, many unknowns exist for each patient. We will highlight only the most pertinent and important.
- Q: Another principle we will emphasize is this: Proper diagnosis should identify the patient’s primary problems in each dimension (anteroposterior, vertical, transverse) plus other major problems (e.g. crowding, ectopic tooth eruption, thin periodontal biotype). Why is this important?
A: These are the problems which will impact your treatment goals and treatment outcome the most. Some will require early treatment. Others are best managed later in development. You must identify primary problems in your diagnosis and develop a treatment plan to address them. During the time you manage each early treatment patient, make it a point to stay focused on the major problems you are facing. If you focus on major problems, then you can gradually reduce these problems and next focus on lesser problems. If you fail to focus on major problems, then the major problems could remain or worsen and detract from the desired outcome.
During your initial patient evaluation, and as you examine the patient at each appointment, always ask yourself: “What are this patient’s primary anteroposterior, vertical, and transverse problems (plus other major problems), and what is my plan to address these problems?” Then, regularly reassess these major problems as you get the child back on track.
- Q: Is early treatment beneficial?
A: It can be. A recent study was conducted with 300 children (mean age nine years) who received treatment via numerous treatment modalities, including 2×4 fixed appliances, cervical or high‐pull headgears (CPHGs, HPHGs), reverse pull headgears (RPHGs), functional appliances, lip bumpers, lower lingual holding arches (LLHAs), and serial extractions. Significant reductions in the American Board of Orthodontics Discrepancy Index were observed [1].
Of course, this does not mean that early treatment is always beneficial. Benefit is maximized when diagnosis is accurate and appropriate treatment is applied. In this book, we will illustrate conditions where early treatment should be considered.
- Q: Can early treatment add to total treatment time?
A: Yes. You must weigh the benefits of early treatment against the cost – including the possible increase in total treatment time. Remember, the cost can be influenced by unknowns that may be revealed after you begin treatment (e.g. aberrant growth or poor compliance). Reducing unknowns is key to weighing benefit vs. cost.
- Q: An orthodontist in your study club complains, “I used to perform a lot of early treatment. I do a lot less now because those cases seemed to drag on and on. I ended up doing most of the treatment in the permanent dentition anyway, and the children complained that they were in braces forever!” How would you respond?
A: We think this orthodontist makes a good point. Early orthodontic treatment should address very specific problems, with a clearly defined endpoint. With the exception of orthopedics for anteroposterior (and open bite) skeletal discrepancies, early treatment should generally begin and end within six to nine months, not drag on for years and years.
Let’s consider a few short examples. Assume a healthy eight‐year‐old boy presents in the early mixed dentition with a Class I molar relationship and displaying one maxillary central incisor tipped lingually and in traumatic edge‐to‐edge occlusion with a mandibular incisor (incisal edge wear noted). A reasonable early treatment of short duration (3–4 months) would be to move the maxillary incisor labially out of traumatic edge‐to‐edge occlusion, and then place the patient in a clear maxillary retainer. Correcting the incisor trauma will get the patient back on track for his stage of development, and eliminating the incisor trauma has a clearly defined endpoint.
Now assume another healthy eight‐year‐old boy presents in the early mixed dentition and displays a bilateral 5 mm Class II molar relationship secondary to mandibular skeletal hypoplasia. Here, it may be best not to begin early treatment for the Class II problem (Class II orthopedics) unless the boy demonstrates good statural growth velocity. Why is this prudent? If growth velocity is slow, then a defined endpoint is less clear and years could be added to his total treatment time. All prospective clinical trials report no advantage in attempting Class II correction in the early mixed dentition (except for possible incisal trauma reduction) [2]. Therefore, unless you can reduce this unknown and establish that your patient has good growth velocity, it may be best to wait to begin treatment.
Our point is that there are many times when you should begin early treatment. There are also many times when you should not begin early treatment. One of the purposes of this text is to provide you with a foundation in making the decision to begin or recall.
- Q: What questions should you ask yourself at every early treatment consultation?
A: Do I need to do anything now? What harm will come if I simply monitor the patient at this time and recall in six to twelve months? If the answer to your question is no harm, then your best treatment may be to monitor only and re‐evaluate later.
- Q: Can you list specific conditions that might warrant early orthodontic treatment?
A: We already mentioned incisor trauma due to edge‐to‐edge relationships or anterior crossbite relationships. Other conditions include dental crowding, eruption problems, excess overjet, skeletal Class II malocclusions in the late mixed dentition (or early mixed dentition if the patient exhibits good statural growth velocity), skeletal Class III malocclusions in the early or late mixed dentition (depending upon severity), deep bites with palatal incisor impingement/pain/tissue trauma upon closing, dental anterior open bites, skeletal anterior open bites (depending upon severity), and posterior crossbites with lateral shifts.
Let’s invite our first patient in for a consultation and make a decision whether to provide early treatment or recall. Theo (Figure 1.1) is an eight‐year‐old boy who presents to us with his parents’ chief complaint, “Theo has a cross bite that we want corrected.” Past medical history (PMH) and Past dental history (PDH) are within the range of normal (WRN). Temporomandibular joint (TMJs) are WRN, and CR = CO.
- Q: What do you notice about the position of the permanent maxillary canines in the lateral cephalometric radiograph (Figure 1.2)?
A: There appears to be a slight difference in their anteroposterior and vertical position.
- Q: What could this be due to?
A: Lack of perfect superimposition of bilateral paired structures on a cephalometric radiograph can be due to:
- The effect of radiographic enlargement on bilateral structures
- Inaccurate patient positioning due to misalignment of the cephalostat or improper patient positioning in the cephalostat
- Marked asymmetry between right and left paired structures
- Marked size differences between right and left paired structures
- Q: What is your assessment of this issue for Theo?
A: First, exact superimposition of right and left paired structures is confounded to a small degree by radiographic enlargement. Enlargement has the greatest impact on bilateral structures farthest from the sagittal midline (e.g. mandibular condyles and gonial angles) [3]. For maxillary canines, which lie closer to the sagittal midline, enlargement of the right vs. left canine in a standard cephalometric radiograph is ~0.15 mm. So, we conclude that the amount of anteroposterior difference in maxillary canines seen in Theo’s cephalometric radiograph (~3 mm) has little contribution from enlargement.
Patient positioning can have dramatic effect on the superimposition of bilateral structures. Rotation of the cephalostat (or rotation of the patient by improper positioning in the cephalostat) by ~10° results in ~5 mm of anteroposterior image separation of the right and left maxillary canines and a larger (~8 mm) separation of the maxillary second molars (due to their greater distance from the mid‐sagittal plane).
Looking at Theo’s cephalometric radiograph, the ear‐rods appear well aligned and the maxillary second molars show minimal (~2 mm) anteroposterior asymmetry. This suggests the anteroposterior image separation of Theo’s maxillary canines does not have a significant contribution from patient rotation and may be due to spatial position asymmetry or size asymmetry of the maxillary canines.
Theo’s panoramic radiograph suggests a vertical height difference in the right and left maxillary canines, supporting the similar finding on the cephalometric radiograph. Finally, bilateral tooth size asymmetry is not apparent.
Taking the cephalometric and panoramic information together, it may indicate a true difference exists in the anteroposterior and vertical positions of the right and left maxillary permanent canines.
- Q: Why is this important?
A: In orthodontic diagnosis, asymmetry in spatial position of bilateral paired structures is a common finding. However, for developing maxillary canines, asymmetry in spatial position may be a clue to impending palatal or facial ectopic eruption and should be investigated further. This evaluation can include manual palpation of the maxillary alveolus from the facial in the area of the developing maxillary canine crowns to detect a difference in right and left prominence in the labial cortical plate, by periapical radiographic assessment using Clark’s rule [4] or by 3‐D radiography. None of these additional evaluations were performed on Theo.
- Q: What is meant by the term apical base? Are the terms apical base discrepancy and skeletal discrepancy interchangeable?
A: The term apical base refers to the junction of the alveolar and basal bones of the maxilla and mandible in the region of the apices of the teeth [5]. We will use the terms apical base discrepancy and skeletal discrepancy interchangeably.
- Q: List your diagnostic findings and problems for Theo and make your diagnosis.
A:
Table 1.1 Diagnostic findings and problems list for Theo (apical base/skeletal discrepancies italicized) .
Full face and profile Frontal view
Slight chin deviation to right
Vertical facial proportions WRN (soft tissue Glabella‐Subnasale approximately equal to Subnasale – soft‐tissue Menton)
Lip competence
UDML WRN
Mildly inadequate gingival display in posed smile (central incisor gingival margins apical to vermillion border of maxillary lip)Profile view
Straight to mildly concave profile
Obtuse nasolabial angle (NLA) with upturned nose
Chin projection WRN
Chin‐throat length WRN
Acute lip‐chin‐throat angleCeph analysis Skeletal
Maxillary anteroposterior skeletal position is retrusive/deficient (A‐Point lies behind Nasion‐perpendicular line, ANB = −2°)
Mandible also appears to be skeletally retrusive/deficient
Skeletal LAFH WRN (LAFH/TAFH × 100% = 56%; normal = 55%, sd = 2%)
Mandibular plane angle WRN (FMA = 25°; SNMP = 36°)
Effective bony Pogonion (Pogonion lies on extended Nasion‐B Point line)Dental
Upright maxillary incisors (U1 to SN = 98°)
Mandibular incisor inclination WRN (FMIA = 67°)Radiographs Early mixed dentition stage of development
Slight overlap of maxillary left permanent canine crown over maxillary left permanent lateral incisor root (possible ectopic eruption)Intraoral photos and models Angle Class III subdivision left
Iowa Classification: I I III (1–2 mm) III (1–2 mm)
OB 20%
Maxillary permanent right central and right lateral incisors in lingual crossbite
5 mm maxillary permanent incisor crowding (moderate crowding, Figure 1.1j)
6 mm mandibular permanent incisor crowding (moderate crowding, Figure 1.1k)
LDML to right of UDML by 2 mm
Maxillary and mandibular arches are symmetric (Figures 1.1j – 1.1k)
Thin labial periodontal biotype of mandibular right central incisor (Figure 1.1h)
Traumatized maxillary central incisors edges (Figure 1.1h)
Retained maxillary right primary lateral incisorOther None Diagnosis Angle Class III subdivision left with anterior crossbite and moderate anterior crowding - Q: We judged Theo’s mandibular skeletal anteroposterior position to be deficient, in spite of the fact that his ANB angle is −2° (an ANB value usually associated with mandibular anteroposterior excess). Why did we judge his mandibular skeletal anteroposterior position to be deficient?
A: If Theo’s maxilla was in a normal anteroposterior position, then A‐Point would lie on the Nasion‐perpendicular line, and we could use ANB angle to judge his mandibular anteroposterior position. However, as discussed in the Appendix, because his maxillary position is deficient (A‐Point lies behind Nasion‐perpendicular line), we cannot use his ANB angle to judge his mandibular anteroposterior position.
Instead, we use the angle formed between the Nasion‐perpendicular line itself and the Nasion B‐Point line to judge his mandibular skeletal anteroposterior position. If we measure this angle (Figure 1.3), we find that it equals 5°, indicating that his mandible is skeletally deficient. In other words, Theo has a skeletally deficient maxilla and mandible.
- Q: But Theo has a straight, even a mildly concave, profile. He does not have a convex profile, which generally indicates a deficient mandible. Furthermore, he has a left side Class III dental relationship – not a Class II dental relationship indicative of a deficient mandible. How do you explain this?
A: The explanation is found in his deficient maxilla. Although Theo’s mandible is deficient relative to Nasion‐perpendicular line, his mandible is excessive relative to his deficient maxilla (ANB angle = −2°). It is not unusual for patients with normal mandibles to appear mandibular excessive when they have a deficient maxilla. We must remain cognizant of this inconsistency as we treatment plan Theo and as we monitor his future growth.
- Q: Theo is eight years old with an upturned nasal tip, adequate chin projection, and adequate chin‐throat length. What changes do you anticipate in his nasal tip, chin projection, and chin‐throat length as he grows and develops?
A: We anticipate that Theo’s nasal tip angle will decrease with age [6] and both his chin projection and chin‐throat length will increase with age [7].
- Q: We noted that Theo exhibits a thin labial periodontal biotype covering his mandibular right central incisor. What does this mean? What is our concern with having a thin labial biotype during orthodontic treatment? How would you deal with this finding?
A: A thin labial biotype is characterized by a narrower zone of attached keratinized tissue than normal and a thinner facial‐lingual gingival dimension than normal. A thick biotype is characterized by a wider zone of attached keratinized tissue and a thicker facial‐lingual gingival dimension [8–12]. If mandibular incisor roots are covered by periodontium exhibiting a thin biotype, then gingival recession may occur if the incisor roots are moved labially or rotated (stressing the tissue). On the other hand, less than 1 mm of attached gingiva may be compatible with gingival health [13–17].
Based upon these points, and because Theo has some keratinized attached gingival tissue labial to his mandibular central incisor, we recommend monitoring Theo’s mandibular anterior gingival tissues for now. However, his parents should be informed that the need for a future gingival graft exists if recession occurs at this site.
- Q: Look at the photographs (Figures 1.1h – 1.1i). What do you note regarding the angulation of the maxillary left permanent lateral incisor? Why could this be important?
A: The maxillary left permanent lateral incisor appears to have its crown inclined to the labial and the root inclined to the lingual. Given the partial overlap of the maxillary left permanent canine crown and maxillary left permanent lateral incisor root (Figure 1.1f), this suggests the crown of the developing maxillary left permanent canine could be positioned to the labial of the lateral incisor root. Orthodontic movement of the lateral incisor root to the labial may cause root resorption.
- Q: We stated that Theo’s Angle Classification was Class III subdivision left and that his Iowa Classification was: I I III (1–2 mm) III (1–2 mm). What do we mean by Iowa Classification?
A: For years, we were frustrated using the Angle Classification system because it fails to quantify – that is to provide the orthodontist with a sense of discrepancy magnitude. In other words, when a patient is said to be Angle Class II does that mean that the patient is slightly Class II or severely Class II? The orthodontist is left without any sense of whether the patient needs Class II elastic wear or orthognathic surgery. Furthermore, we feel that canine anteroposterior relationships are just as important as molar relationships. The Angle Classification system lacks this detail.
We decided to modify the Angle system by quantifying the anteroposterior discrepancy at the patient’s right molar, right canine, left canine, and left molar. (Please see the Appendix). For Theo that results in an Iowa Classification of: I I III (1–2 mm) III (1–2 mm).
- Q: What are Theo’s primary, or major, problems in each dimension, plus other problems that you need to remain focused on?
A:
Table 1.2 Primary problems list for Theo (apical base/skeletal discrepancies italicized) .
AP Angle Class III subdivision left
Iowa Classification: I I III (1–2 mm) III (1–2 mm)
Maxillary and mandibular skeletal anteroposterior deficiencyVertical ‐ Transverse ‐ Other Anterior crossbite
Possible ectopic eruption of maxillary left permanent canine
Moderate anterior crowding in both arches- Q: Discuss Theo in the context of three principles applied to every early treatment patient.1)
- The goal of early treatment is to correct developing problems – get the patient back to normal for their stage of development (including preventing complications such as resorption of adjacent tooth roots, reducing later treatment complexity, or reducing/eliminating unknowns). Theo’s anterior crossbite, left Class III relationship, maxillary left permanent canine possible ectopic eruption, and moderate anterior crowding would need to be corrected to get him back to normal.
- Early treatment should be applied to correct very specific problems with a clearly defined endpoint, usually within six to nine months (except for anteroposterior skeletal and skeletal open‐bite orthopedics). Correction of Theo’s anterior crossbite has a clearly defined endpoint and could be accomplished with fixed orthodontics in a few months. His moderate anterior crowding has a clearly defined endpoint, but improvement/correction could take longer than six to nine months (using space maintenance/fixed appliances) depending upon how long it takes his permanent canines and premolars to erupt. Correction of his possible ectopically erupting maxillary left permanent canine could take longer than nine months. Finally, correction of Theo’s left Class III relationship could take years of orthopedic treatment, depending upon his future growth and compliance.
- Always ask: Is it necessary that I treat the patient now? What harm will come if I choose to do nothing? It is important to treat Theo’s anterior crossbite now to prevent additional incisor trauma/wear.
Without early treatment anterior crowding will remain, and unerupted permanent canines could become impacted or erupt blocked out. The risk of maxillary left permanent canine impaction is of special concern to us (note overlap of the maxillary left permanent canine crown across the maxillary left lateral incisor root, Figure 1.1f). Further, the maxillary left permanent canine crown could resorb the maxillary left permanent lateral incisor root.
Without Class III orthopedic treatment, maxillary deficient forward growth (relative to mandibular forward growth) could worsen Theo’s left Class III relationship. Worsening of Theo’s left Class III relationship could also result from mandibular permanent first molar mesial drift if an LLHA is not placed before exfoliation of his mandibular primary canines and molars.
- Q: We noted that Theo’s chin is deviated slightly to the right, CR = CO, his LDML is to the right of his UDML and face, and he is Class III on the left by 1–2 mm. What do these findings suggest?
A: These findings suggest that his mandible may be growing asymmetrically, with slight excess left mandibular forward growth.
- Q: What unknowns do you face with Theo’s care?
A: His future jaw growth (magnitude and direction), treatment compliance, and a potential undetected CR‐CO shift are significant unknowns.
- Q: What early treatment option(s) would you consider for Theo?
A: Early treatment options could include:
- Recall (monitor only) and re‐evaluate in one year – is not a recommended option. Why? Risks include additional incisor trauma, increasing ectopic eruption of Theo’s maxillary left permanent canine (increasing the risk of canine impaction and/or lateral incisor root resorption [16]), and continued Class III skeletal growth.
- Anterior crossbite correction – is recommended and could be performed in a number of ways. After extracting his maxillary right primary lateral incisor, you could: (i) ask Theo to close gently on a tongue blade covered with gauze (or on a soft suction tip) throughout the day in order to advance his right maxillary incisors; (ii) ask Theo to wear a removable maxillary biteplate with finger springs to advance his maxillary incisors; or (iii) place fixed orthodontic appliances to advance his maxillary right incisors. Also, some anterior crossbites will self‐correct from tongue pressure alone if the patient’s bite is first opened with bilateral band cement bonded on the permanent first molar occlusal surfaces.
Note: advancing the maxillary right lateral incisor crown forward will tend to drive its root reciprocally into the erupting canine crown – potentially resorbing the lateral incisor root. This must be explained to the parents. If you advance the lateral incisor crown, do so gently and slowly.
- Extracting his maxillary primary canines and maxillary primary first molars – is a viable option when his maxillary first premolar roots are at least half developed. Why? Eruption of the maxillary first premolars would be accelerated, which would make room for the maxillary permanent canines to erupt, thereby lessening the chance that his maxillary left permanent canine will be impacted [18, 19]. Generally, a primary tooth should not be removed until its permanent successor has at least half of its root length formed [20, 21]. Earlier primary tooth extraction can cause delayed eruption and emergence of its successor, probably as a result of scar tissue forming a mechanical barrier [22].
- Space maintenance – is recommended, but not yet. Placement of an LLHA could (i) prevent/minimize worsening of Theo’s left Class III relationship due to permanent first molar mesial drift as his mandibular primary teeth exfoliate; and (ii) reduce mandibular anterior crowding as primary teeth exfoliate (leeway space). However, since the roots of his mandibular permanent canines and premolars are less than half formed (Figure 1.1f), their eruption is not imminent and placement of an LLHA would be premature [23].
- Extraction of mandibular primary canines – to permit spontaneous mandibular incisor alignment. We do not recommend this option since mandibular incisor crowding is not a concern for Theo or his parents. If you decided to extract mandibular primary canines, then we would strongly recommend placement of an LLHA to maintain arch perimeter and reduce mesial molar drift (worsening of the left Class III relationship).
- Orthopedic treatment (e.g. reverse pull face mask therapy) – is a possible option to improve/correct Theo’s left Class III molar relationship by advancing his maxilla/maxillary teeth. Note: orthopedic treatment will not normalize Theo’s growth. If Theo’s maxilla is advanced orthopedically, then its position will need to be overcorrected in anticipation of future deficient maxillary growth, or he will need to be placed in a high‐pull chin cup (or temporary anchorage device (TAD)‐supported Class III elastics) to maintain the correction – until he is finished growing. If excess left asymmetric mandible forward growth is identified, then asymmetric orthopedics (TAD supported Class III elastics) may be required on his left.
- Extraction of his retained maxillary right primary lateral incisor – is recommended if it does not exfoliate spontaneously.
- Q: Based upon the above discussion, do you recommend recalling Theo in nine to twelve months (no treatment, monitoring only), or, do you recommend early treatment? If you recommend early treatment, what treatment would you perform?
A: We extracted Theo’s maxillary right primary lateral incisor. Our early treatment objective was to correct his maxillary right central incisor crossbite by advancing it with fixed appliances and compressed open coil springs placed between his central incisors and primary canines (Figure 1.4). Band cement was bonded to the occlusal surfaces of his maxillary first permanent molars as a bite plate to open his bite and allow his maxillary right central incisor to advance, unimpeded.
We did not bracket the maxillary lateral incisors because they were not in traumatic occlusion and because we were concerned about possibly driving their roots reciprocally into the erupting permanent canine crowns (potential root resorption). Surprisingly, the maxillary right permanent lateral incisor spontaneously shifted forward out of lingual crossbite following extraction of the maxillary right primary lateral incisor and advancement of the maxillary right permanent central incisor (Figure 1.4).
We decided to delay placement of an LLHA until Theo’s mandibular permanent canines and premolars were closer to eruption. Also, we decided to postpone Class III orthopedic treatment. Why? Although Theo’s anteroposterior relationship would be monitored, orthopedic treatment was deemed aggressive at this time considering his mild unilateral Class III magnitude (1–2 mm).
Finally, we decided not to extract Theo’s maxillary primary canines and maxillary primary first molars. Why? The maxillary left permanent canine crown overlap of the maxillary left lateral incisor root was minimal (Figure 1.1f), and his first premolar roots were less than half developed.
- Q: Look at Theo’s early treatment deband photographs (Figure 1.5). Was our early treatment successful? Did we achieve our goals?
A: Yes and no. We achieved our goal to correct Theo’s anterior crossbite. However, he is still Class III on his left side, he still has mandibular anterior crowding, and his maxillary left permanent canine is still erupting ectopically. These are problems that we must continue to monitor and eventually address to get him back on track.
- Q: How do you recommend proceeding?
A: We made Theo an appointment to return in one year. At that time, we planned to make another panoramic radiograph. If Theo’s maxillary left permanent canine crown was seen to overlap his maxillary permanent lateral incisor root more than on the initial panoramic radiograph, then we would extract his maxillary primary canines and primary first molars (assuming the premolar roots were at least half developed). These extractions would accelerate eruption of the first premolars and thus create an eruption path for the permanent canines.
We planned to place an LLHA when Theo approached exfoliation of his mandibular primary canines and primary molars. Finally, we planned to monitor his left Class III relationship, instituting orthopedic treatment (RPHG, high‐pull chin cup, or TAD‐supported Class III elastics), if his left Class III relationship worsened.
- Q: Despite repeated attempts to schedule Theo to return to our clinic, he failed to do so until he was fifteen years old (Figure 1.6). List changes that have occurred since we last saw him (Figure 1.5).
A: Changes include:
- Most permanent teeth have erupted, but the maxillary right primary canine and mandibular left primary canine are retained.
- Theo had significant Class III dental compensation changes. His maxillary incisors proclined (U1 to SN angle increased from 98° to 108°, compare (Figures 1.1e and 1.6e) while his mandibular incisors uprighted (FMIA increased from 67° to 77°).
- Worsening of his right occlusal relationship to Class III (1 mm), and slight improvement on his left side from Class III (1–2 mm) to nearly Class I. Why? One possible explanation is that Theo grew Class III skeletally but had more available space in his upper left quadrant from lateral incisor to molar (Figure 1.5g) than in his upper right quadrant, which allowed him to obtain dental Class I on the left during permanent tooth eruption and mesial drift.
- Maxillary left permanent canine, the canine that initially concerned us, erupted normally. However, the maxillary right permanent canine became palatally impacted (Figure 1.6f). Note the slight palatal soft‐tissue bulge covering the impacted maxillary right permanent canine (Figure 1.6j).
- Both mandibular canines erupted into 90° rotated positions (Figure 1.6k). The mandibular left canine erupted lingually.
- A moderate amount of mandibular anterior crowding exists (~6 mm of total mandibular permanent canine crowding)
- The mandibular anterior labial periodontal biotype appears to have thickened (Figure 1.6h)
- We noted that Theo’s maxillary lateral incisors were small mesiodistally. His parents were informed that he would possibly need composite veneers to give them a more ideal mesiodistal width.
- Q: Could we have prevented palatal impaction of the maxillary right permanent canine?
A: Possibly. If further investigation of the noted asymmetry of the maxillary permanent canines had been done, our findings may have prompted us to be more aggressive toward improving the potential for its normal eruption. Theo’s lack of appointment compliance also limited our ability to monitor and evaluate its development.
This raises an important point. Early treatment always involves a monitor and evaluate component, be it when you decide no early treatment is needed and place your patient on recall, or when you have completed a focused early treatment and continue to monitor the patient. You must always stress to the parents of early treatment patients that periodic observation is important to minimize developing problems. We may have been able to lessen Theo’s developing maxillary canine problem if periodic observation had been maintained.
- Q: We noted that Theo’s mandibular anterior labial periodontium appears to have thickened. What does the literature say about maxillary and mandibular anterior labial keratinized gingival widths in children six to twelve years of age?
A: In well‐aligned teeth, increases in width of the facial keratinized and attached gingiva can take place [13].
- Q: Was Theo’s early treatment warranted?
A: Yes. Correction of Theo’s anterior incisor crossbite was effective and necessary.
- Q: What else should have been done during the years that Theo failed to return to clinic?
A: An LLHA should have been placed before exfoliation of Theo’s primary canines and primary molars in order to:
- Prevent mesial drift of mandibular molars. If mandibular molar mesial drift had been prevented, then Theo could now be in a bilateral Class I molar relationship instead of Class III on his right.
- Provide leeway space for improved mandibular anterior teeth alignment (especially mandibular canine alignment)
In addition, periodic panoramic radiographs should have been made in order to evaluate the eruption path of the permanent maxillary canines. We would have likely seen the earlier ectopic path of the maxillary left permanent canine improving with growth. The eventual ectopic path of the maxillary right permanent canine would have been seen earlier in Theo’s development, allowing steps to be taken to improve the path of eruption prior to the full development of his adolescent dentition.
Also, Theo’s growth should have been monitored, annually. We were lucky that Theo did not grow more Class III than he did. Periodic observation is important to minimize the difficulty of developing problems.
- Q: Except for two retained primary teeth, Theo is now in the permanent dentition and ready for comprehensive orthodontic treatment. Although comprehensive treatment is not the focus of this book, do you have any recommendations on how to proceed?
A: Theo’s mandibular incisors are upright, their labial periodontium has thickened, and he exhibits approximately 6 mm of mandibular anterior crowding. For these reasons, we decided to attempt comprehensive nonextraction treatment by aligning the mandibular anterior teeth. As they are aligned, the incisors will procline and tend to move into anterior crossbite. To avoid this, overjet would need to be created by proclining the maxillary incisors (spaces would be opened for composite veneers on the distal of the small maxillary lateral incisors). A reasonable alternative treatment would be to extract a mandibular incisor to gain space for alignment. This treatment would result in less maxillary incisor proclination but more upright mandibular incisors.
Treatment began. To address the impacted maxillary right permanent canine, a transpalatal arch was placed, and a distal elastic traction force applied to the impacted maxillary right canine after it was surgically exposed. This force pulled the maxillary right canine crown away from the maxillary right lateral incisor root before the canine was moved laterally into arch alignment. We did this in order to avoid resorption of the lateral incisor root by the canine crown. The two retained primary canines were extracted. Maxillary fixed orthodontic appliances were placed. Using elastics, the maxillary right permanent canine was moved laterally into alignment within the arch (Figure 1.7a).
Anterior overjet was next created by making spaces between the maxillary lateral incisors and maxillary canines using open coil springs. This overjet would allow alignment (proclination) of mandibular anterior teeth without creating an anterior crossbite. A few months later, we noticed that Theo had grown more Class III (2 mm). He was placed on a high‐pull chin cup (Figure 1.7b, 250 grams per side) to reduce and re‐direct mandibular forward growth while hoping maxillary forward growth would continue. He wore it from eight pm each night until morning.
Theo was very compliant with chin cup wear. Mandibular‐fixed orthodontic appliances were placed, and both arches were leveled and aligned (Figure 1.7c–g). Note in Figure 1.7g that space is being created for the mandibular right canine using a compressed open coil spring inserted between the lateral incisor and first premolar, and the mandibular left canine is being rotated with a couple (equal but opposite elastic forces on the buccal and lingual canine surfaces). Because of his excellent chin cup wear, Theo’s Class III molar and canine relationships did not worsen, and we felt comfortable using Class III elastics to correct his 2 mm Class III relationship (Figures 1.7h–1.7i).
We began closing maxillary anterior spaces until anterior overjet was eliminated. The black triangle between his maxillary central incisors (Figure 1.7d) was eliminated by enameloplasty of the mesio‐incisal corners of the central incisors followed by space closure. Because Theo’s maxillary lateral incisors were small, we anticipated him needing maxillary lateral incisor composite veneers at the end of treatment to fill in residual spaces and give his maxillary lateral incisors the correct mesiodistal widths. However, we found that when a Class I canine relationship was achieved, we were able to close all maxillary spaces. This probably occurred because his mandibular incisors were upright (mandibular incisal edges were further back requiring less overjet than if they were proclined).
Theo’s height was monitored throughout comprehensive treatment. By age seventeen he had stopped growing. Comprehensive orthodontic treatment, including finishing, was completed by age eighteen (deband records are shown in Figures 1.7k–1.7u). He was placed in maxillary and mandibular Hawley retainers.
We were pleased with Theo’s final facial esthetics, smile, function, and occlusion. As expected, Theo had significant facial growth during comprehensive treatment (cephalometric superimpositions, Figure 1.7p). His maxilla underwent anterior rotation as a result of growth and treatment moving downward posteriorly and showing very little forward growth overall. His mandible grew downward and forward with mild anterior rotation.
We were not pleased with the uprightness of his mandibular incisors nor with the proclination of his maxillary incisors (Figures 1.7n and 1.7o), which reflect dental compensations for his differential maxillo‐mandibular growth (mandible grew forward significantly, maxilla grew forward considerably less). We were not pleased with the second‐order angulation of his maxillary left second premolar and his mandibular right lateral incisor (Figure 1.7j). His maxillary left lateral incisor also displays too much mesial and lingual root angulation, contributing to the appearance of a shorter clinical crown. This was the clinical position of this tooth at the start of early treatment, and we neglected to focus on this problem during comprehensive treatment.
Finishing imperfections notwithstanding, Theo and his parents were ready to have his braces removed. We recommended that Theo have his maxillary left lateral incisor lengthened slightly with a composite veneer, but Theo declined.
In summary, Theo’s early treatment consisted of anterior crossbite correction, which was completed by nine years of age and which prevented further incisor damage. However, we failed to place an LLHA at that time, we wish we had instituted Class III orthopedic treatment sooner than we did, but Theo disappeared for six years.
- Q: Theo was included as an example in this section in order to underscore important concepts about early treatment diagnosis, treatment planning, and treatment delivery. Can you suggest other important concepts that his case illustrates?
A: These concepts are as follows:
- Early treatment is only one piece of total orthodontic care. Early treatment can be critically important. However, even if you get your patient back on track with early treatment, total treatment is incomplete until you have achieved excellent adult occlusion, function, tissue health, and facial esthetics. In addition, even after you successfully complete comprehensive treatment in the adult dentition, you must monitor the patient in retention. We did the right thing by treating Theo’s anterior crossbite early, but we were committed to caring for him until his comprehensive treatment was complete as an adult – and beyond.
- Orthodontic treatment, including early orthodontic treatment, relies heavily on patient compliance. Theo failed to return to our clinic for years, during which time important early treatment opportunities (growth modification, space maintenance, and management of ectopically erupting teeth) were missed. Periodic observation is important to minimize the difficulty of developing problems.
- Cephalometric findings should corroborate clinical observations. When inconsistencies are noted between cephalometric findings and clinical observations, pay special attention. According to his cephalometric analysis, Theo presented with an anteroposterior mandibular deficiency (relative to Nasion‐perpendicular line). Clinically, he appeared to be developing a Class III malocclusion presumably due to greater mandibular anteroposterior skeletal growth than maxillary anteroposterior skeletal growth. Our cephalometric indicators may have suggested mild mandibular skeletal hypoplasia, but our initial clinical impression was correct.
- Due to his initial slight chin deviation to the right, lower dental midline to the right, Class III on the left by 1–2 mm, and CR = CO, we would have expected Theo to continue mandibular left asymmetric excess growth. Such an asymmetric growth pattern was not evident long term. Close monitoring during treatment allows for change of treatment plan in response to unanticipated growth or treatment response.
- Q: Which early treatment cases are best avoided?
A: Be wary of severe skeletal Class II, severe skeletal Class III, or severe skeletal open‐bite discrepancies. For example, a recent study reported that early, two‐phase treatment for severe Class II high‐angle patients offered no skeletal or dental advantage over later 1‐phase treatment [24]. Exceptions to this guideline include severe skeletal discrepancy patients where there is a clear psychosocial (cosmetic) benefit to be gained from early treatment, when early treatment will dramatically simplify future (surgical) treatment, or when risk of dental injuries due to excess overjet is a concern [25, 26].
- Q: Why is the above guideline important?
A: Skeletal jaw discrepancies in the anteroposterior, vertical, or transverse dimensions are treated in one of three ways: orthopedics, masking, or surgery. Dentofacial orthopedics uses forces to modify jaw growth and correct skeletal discrepancies. Masking (camouflage) corrects the occlusion dentally without correcting the underlying skeletal discrepancy. An example of masking would be skeletal Class II treatment via extraction of maxillary first premolars to create space for retracting maxillary canines from Class II into a Class I relationship. Masking and orthognathic surgery are generally considered only in the permanent dentition after growth is complete or nearly complete.
Orthopedics is the early treatment of choice for skeletal discrepancies. Whenever considering orthopedic treatment, you must reflect on the magnitude of the skeletal discrepancy and the time remaining to correct it.
Magnitude:
- For mild skeletal discrepancies: orthopedic correction may be possible with reasonable growth amount, direction, and patient cooperation.
- For moderate anteroposterior and skeletal open‐bite discrepancies: orthopedic correction is less likely, but improvement with orthopedics may be enough to permit successful masking. In other words, a final dental correction with reasonable facial esthetics may be achieved if early orthopedic skeletal improvement is first obtained. When successful, this generally minimizes the need to consider surgical correction as part of comprehensive treatment of the adolescent dentition.
- For severe anteroposterior and skeletal open‐bite discrepancies: orthopedic correction is unlikely. If attempting orthopedics in these severe skeletal discrepancy patients, you must ensure that irreversible dental compensations are not placed, which would make later surgical correction difficult. We have made this mistake ourselves by placing a Class II patient with severe mandibular deficiency on a headgear only to find that dental correction was made by distal movement of the maxillary dentition. When the patient later requested a mandibular advancement osteotomy to improve her chin projection, the surgical advancement was limited because the maxillary teeth had been retracted.
With severe skeletal discrepancies, a decision must be made whether to attempt early orthopedics to the point where masking is possible (with good facial esthetics) or to postpone (surgical) treatment until after growth is complete. If we attempt early orthopedics in severe skeletal discrepancy cases it is with the parent’s understanding that we will closely monitor to see what response we get (reduce unknowns) and that future orthognathic surgery is likely.
Time:
- Time of remaining growth can be your friend and your enemy.
- Time is your friend because the potential for orthopedic growth modification is maximized if you have years of growth remaining.
- Time is your enemy because most patients are not infinitely compliant. They may cooperate for months, or even years, but they will eventually stop. Beyond that point, additional orthopedic growth modification usually ends.
- Time is your enemy because orthopedic treatment does not normalize the underlying jaw growth pattern. In other words, assume you begin orthopedic treatment, the skeletal correction is made, and you stop orthopedic treatment. If the patient is still growing, then the previous growth pattern will return, and the patient may grow out of your correction.
- Q: Jack (Figure 1.8) is ten years old and presents to you with the parents’ CC: “Jack needs orthodontic treatment.” PMH includes hydrocephaly, Goldenhar syndrome (oculo‐auriculo‐vertebral syndrome), hypoplastic left pinna, antimongoloid slant of palpebral tissues, right‐to‐left nares imbalance, fusion of atlas‐axis, antibiotic prophylactic coverage required for dental procedures, and hemophilia. PDH and TMJ evaluations are WRN. CR‐CO left lateral shift of 2 mm. Dentally, he is in the transition between early and late mixed dentitions. List your diagnostic findings and problem list for Jack.
A:
Table 1.3 Diagnostic findings and problem list for Jack.
Full face and profile Frontal view
Face is symmetric
Long soft‐tissue LAFH (soft‐tissue Glabella‐Subnasale < Subnasale – soft‐tissue Menton)
Mentalis strain to achieve lip competence
UDML 3 mm to right of facial midline
Large buccal corridors
Inadequate gingival display in posed smile (central incisor gingival margins apical to vermillion border of maxillary lip)
Profile view
Convex profile
Obtuse NLA
Retrusive chin
Mildly procumbent mandibular lipCeph analysis Skeletal
Maxillary anteroposterior retrusion (as indicated by A‐Point being positioned behind Nasion‐perpendicular line. However, Jack’s syndrome may prevent us from using this measure to judge maxillary position. In fact, his maxillary anteroposterior position looks reasonably normal in the natural head position (Figure 1.8e).
Mandibular anteroposterior deficiency/retrusion
Long skeletal LAFH (LAFH/TAFH100% = 61%)
Steep MPA (FMA = 36°, SNMP = 47°)
Pronounced antegonial notching
Vertical maxillary excess (VME)
Ineffective bony Pogonion (Pogonion lies behind extended Nasion B‐Point line)Dental
Maxillary incisor angulation appears WRN relative to natural head position (Figure 1.8e), but U1 to SN angle = 94° indicating upright maxillary incisors
Proclined mandibular incisors (FMIA = 49°)Radiographs Hydrocephaly shunt (Figure 1.8d)
Right condylar hypoplasia or absence (difficult to see due to superimposition of other bony structures (Figure 1.8f)
Left condyle is flattened
Ectopic eruption of maxillary right permanent first molar
Transition between early and late mixed dentition stages of developmentIntraoral photos and models Angle Class III subdivision right
Iowa Classification: III (4 mm) X I I (X indicates that right canine is missing)
Anterior open bite extending posteriorly to the permanent first molars
Bilateral posterior lingual crossbite
UDML 3 mm right of LDML
Mandibular transverse dental compensations (Figure 1.8h, mandibular permanent first molar lingual crown torque)
Severe maxillary and mandibular anterior dental crowdingOther ‐ Diagnosis Angle Class III subdivision right skeletal open bite with VME, mandibular skeletal anteroposterior hypoplasia, bilateral posterior lingual crossbite due to maxillary transverse skeletal deficiency, and severe crowding - Q: What are Jack’s primary problems you must stay focused on?
A:
Table 1.4 Primary problems list for Jack apical base/skeletal discrepancies italicized .
AP Angle Class III subdivision right with m andibular skeletal retrusion Vertical Skeletal open bite (VME, skeletal long LAFH) Transverse Maxillary transverse skeletal deficiency with bilateral lingual crossbite Other Severe maxillary and mandibular anterior crowding - Q: Jack has skeletal problems in all three facial dimensions. Let’s start with the vertical and anteroposterior dimensions. Should you begin early (orthopedic) treatment to address these? If yes, what treatment would you recommend?
A: The skeletal and dental problems confronting Jack are severe. In the vertical dimension, an attempt to orthopedically close his skeletal anterior open bite (and to maintain closure of the open bite) would require exceptionally long treatment with an uncertain outcome. Even if you placed TADs in both arches as anchors to intrude his posterior teeth, or simply to prevent eruption of his posterior teeth (relative intrusion), the TADs would need to remain in place until Jack completed growth. The effects of such a treatment on his developing airway are unknown.
Compared to his vertical skeletal discrepancy, Jack’s anteroposterior skeletal discrepancy is more moderate. As Jack is entering the late mixed dentition stage of development, an attempt could be made to improve his anteroposterior skeletal relationship using orthopedics. However, high‐pull headgear wear is prohibited because the headgear straps could occlude Jack’s hydrocephaly shunt (tubing is palpable). Further, we do not recommend Class II functional appliance wear because it would further procline his mandibular incisors and promote a deleterious backward mandibular rotation [27].
For the above reasons, we decided not to attempt orthopedics in the vertical or anteroposterior dimensions but instead chose to wait until Jack had completed growth. Surgery would be the treatment option of choice at that time.
- Q: What about Jack’s transverse dimension? Should you begin early orthopedic treatment to address his posterior crossbite?
A: Yes, limited early transverse treatment could simplify future comprehensive treatment. If Jack’s maxillary transverse deficiency can be corrected now with orthopedics, then the need for a future multiple‐piece maxillary osteotomy (MPMO) to widen his maxilla, or the need for a future surgically assisted rapid maxillary expansion (SARME) procedure, could be eliminated. In other words, if Jack’s maxilla can be widened now with RME, then a maxillary one‐piece impaction osteotomy could someday correct his skeletal open bite – dramatically reducing the complexity of the maxillary surgery.
For these reasons, the maxillary right primary second molar and maxillary left primary first molar were extracted. After the ectopically erupting maxillary right permanent first molar and both maxillary first premolars erupted, a Hyrax expansion appliance was delivered and RME begun (Figure 1.9). An expanded LLHA (with labial molar crown torque) was also inserted to upright the mandibular first permanent molars (Figure 1.9e) and allow maximum expansion of the maxilla by removing the mandibular transverse compensations.
Finally, in an attempt to maintain the vertical dimension as much as possible, Jack was asked to chew gum (exercise) every day. Previous studies have shown that daily chewing exercises resulted in a significant decrease in the mandibular plane angle or assisted in orthodontic treatment to close anterior open bites [28, 29]. Jack developed recurrent coagulopathy problems, and his mother decided to discontinue orthodontic treatment until he was an adult.
- Q: Caden (Figure 1.10) is nine years and seven months old. He was referred to you by his pediatric dentist for orthodontic treatment. Caden tells you, “I do not want braces.” His mother says Caden had a small jaw when he was born and that, “Caden is not the best at cooperating.” PMH, PDH, and TMJ evaluations are WRN and CR = CO. Caden cries during your examination and when your staff makes records. What are Caden’s primary problems in each dimension (plus other problems)?
A:
Table 1.5 Primary problems list for Caden apical base/skeletal discrepancies italicized .
AP Angle Class II division 2
Iowa Classification: II (7 mm) X X II (6 mm)
Mandibular skeletal deficiencyVertical 90% OB Transverse ‐ Other Potentially impacted maxillary permanent canines
Poor hygiene
Localized juvenile spongiotic gingival hyperplasia (maxillary left anterior)- Q: We have one specific question. Would you begin early (orthopedic) treatment to address Caden’s Class II skeletal discrepancy? If yes, what treatment would you recommend?
A: Because Caden has a severe mandibular skeletal deficiency, a negative attitude toward orthodontic treatment, a history of mediocre cooperation, and evidence of poor oral hygiene, we do not recommend attempting orthopedic treatment. We recommend waiting until he reaches maturity when, if he is interested in treatment, a mandibular advancement osteotomy could be considered.
- Q: Do you recommend avoiding other types of cases?
A: We are reluctant to treat patients with severe disabilities unless they are able to perform all functions needed to secure a successful outcome. Otherwise, treatment is frustrating for patient and doctor. Also, we recommend that you confirm treatment is something the child wants. You are providing care for the child, not the parent. A desire for treatment must come from the child.
- Q: Can you suggest general principles to follow regarding patient compliance during early treatment?
A: General principles include the following:
- “Each patient is blessed with one cup of compliance.” (Dr. Mike Callan). When it is gone, it is gone. Design your treatment to be as efficacious as possible over the shortest time possible. For some treatments (e.g. Class III orthopedics), the patient may need to exhibit super‐human compliance over many years until they are finished growing.
- Always have a fallback plan (contingency plan) if your primary treatment plan fails due to lack of cooperation. For example, in Class III treatment, you may be forced to offer permanent tooth extractions or orthognathic surgery if the patient’s response to orthopedic treatment is less than desired.
- Q: Let’s briefly discuss the need for early treatment in terms of esthetics and self‐esteem. Dylan, a seven‐year‐old boy, presents for a consultation (Figure 1.11) with his mother’s CC, “Dylan is teased at school because his front tooth sticks out. He is very self‐conscious about it. I went to another orthodontist who refused to do anything about it. He said it was too early. I want his front tooth corrected.” You examine Dylan. PMH, PDH, TMJ’s, and periodontal tissues are normal. CR = CO. What do you observe?
A: Overall, Dylan appears to be developing normally. His face is symmetric with a normal LAFH and mildly convex profile. He is in the early mixed dentition and exhibits a mesiodens (Figure 1.11d). He has a Class I canine and molar relationship, normal OB of the maxillary right central incisor, and 50% OB of the maxillary left central incisor. He has a normal transverse relationship (but large buccal corridors, Figure 1.11b), mild mandibular anterior crowding, and premature loss of mandibular right primary first molar with the space being maintained by a band and loop appliance (Figure 1.11i). His maxillary left central incisor is severely rotated/proclined, and he has a large diastema between his maxillary central incisors. There is an absence of either hard or soft‐tissue damage resulting from this malalignment.
- Q: What is the cause of the misaligned incisor?
A: The etiology is unknown. However, the presence of a mesiodens may have contributed to the ectopic eruption of the maxillary left permanent central incisor.
- Q: Do issues of poor self‐esteem, such as Dylan’s, warrant early orthodontic intervention?
A: Generally, no. [30] For instance, in Class II patients, early treatment had no effect on self‐esteem [26]. However, orthodontic treatment can improve self‐concept and decrease negative social experiences [31, 32]. So, the question of whether to provide early treatment in the hope of improving self‐concept (everything you know about yourself) or self‐esteem (how you rate what you know about yourself) must be dealt with on a case‐by‐case basis. If a child is being teased about their dental condition, then this could be justification for early treatment.
- Q: His mother’s chief complaint offers us an important “take‐home pearl”. What is it?
A: Be cautious about letting parents dictate orthodontic treatment. You should treat only if you consider the treatment to be of benefit, reasonable, and what you would want for your own child.
- Q: You decide to provide early treatment to address the malpositioned maxillary left central incisor. What treatment would you recommend?
A: The supernumerary tooth between the maxillary central incisors (Figure 1.11d) was surgically removed, fixed orthodontic appliances were bonded to the maxillary central incisors and maxillary primary second molars, the diastema was closed, and the maxillary left central incisor was aligned (Figure 1.12). A circumferential supracrestal fiberotomy (CSF, Figure 1.12e) was then performed.
- Q: Why did we request a CSF for Dylan?
A: Severing the gingival fibers around the sulcus of a tooth (to the alveolar crest) may reduce posttreatment relapse. CSFs have been shown to be more effective in alleviating pure rotational relapse than in reducing labiolingual relapse [33] and more successful in reducing relapse in the maxillary anterior segment than reducing relapse in the mandibular anterior segment. With his severe maxillary left central incisor rotation, Dylan was the perfect candidate for a CSF.
- Q: In addition to requesting a CSF, how else would you recommend retaining his maxillary central incisor’s corrected alignment?
A: We placed a fixed lingual retainer/wire bonded between Dylan’s maxillary central incisors.
Notes: (i) OB must be shallow (not deep) in order to bond a fixed maxillary lingual retainer so that the mandibular incisors do not occlude against it; and (ii) it is a good idea to bond the fixed maxillary lingual retainer at least one month before the debanding appointment in order to monitor that it will remain attached. A clear, vacuum‐formed retainer covering his palate and maxillary incisors was also given to Dylan to be worn at night until additional permanent teeth erupt.
- Q: Figure 1.13 shows Dylan at deband. What changes do you observe?
A: The severe rotation of his maxillary left central incisor has been corrected resulting in significant improvement of Dylan’s smile esthetics. He will be monitored for additional early treatment (e.g. placement of an LLHA to help alleviate mandibular anterior crowding) and later comprehensive treatment.
- Q: Was Dylan’s early treatment warranted?
A: Early treatment to improve a child’s self‐concept or self‐esteem must be made on a case‐by‐case basis. On the one hand, you could argue that no tissue damage was occurring from the malaligned maxillary left central incisor and that correction of the malaligned tooth could have been postponed until comprehensive treatment in the adult dentition. On the other hand, Dylan and his mother were delighted with the correction and stated that the teasing at school had stopped. We feel like his treatment was warranted.
- Q: What are your “take‐home pearls” from this section?
A: “Take‐home pearls” include the following:
- The goal of early treatment is to correct developing problems – get the patient back to normal for their stage of development (including preventing complications, reducing later treatment complexity, and reducing/eliminating unknowns).
- Early treatment should be applied to correct very specific problems with a clearly defined end point, usually within six to nine months. Early treatment should generally not drag out for years and years into comprehensive treatment. There are exceptions to this guideline, including orthopedic treatment of some developing skeletal problems, such as skeletal Class III malocclusions.
- When deciding whether to begin early treatment, always ask, “Is it necessary that I treat the child now? What harm can come if I choose to do nothing now – if I recall the patient in 6–12 months?” One of the hardest things for orthodontists to do is to wait.
- Focus on the patient’s primary problems in each dimension (plus other major problems).
- Before beginning treatment, always ask, “What unknowns am I facing?” Whenever possible, reduce your unknowns first – before establishing a final treatment plan but especially before doing anything irreversible (e.g. extracting permanent teeth).
- Always have a fallback plan (contingency plan) if your primary treatment plan fails due to lack of patient compliance or unfavorable growth.
- Early treatment involves frequent monitoring of patients. Adjustments to plans are made as you deem appropriate.
- When considering orthopedic treatment, reflect on the magnitude of the skeletal discrepancy and the time (potential growth) remaining to address it.
- As a rule, avoid early orthopedic treatment of severe skeletal Class II, severe skeletal Class III, or severe skeletal open‐bite discrepancies. In such severe cases, some limited early treatment may be recommended to improve the patient’s appearance (psychosocial benefit) or if early treatment will dramatically simplify future treatment. We will often recommend early correction of severe maxillary transverse skeletal deficiencies in order to avoid later (surgical) maxillary expansion.
- Masking (camouflage) and orthognathic surgery are generally not considered as early treatment options. Orthopedics is the skeletal discrepancy early treatment of choice.
- Be wary of early treatment cases when the patient is severely disabled unless the patient has expressed a strong desire for treatment and is able to perform all necessary functions to insure a successful outcome.
- Decisions to provide early treatment to improve a child’s self‐concept or self‐esteem are made on a case‐by‐case basis.
- Early treatment can offer significant benefits. However, it can also result in prolonged treatment times, worse final clinical assessments, and increased incidences of patient/parent “burn‐out.” [34] Be selective when applying early treatment. This text will provide a foundation for helping you to decide when to do so.
- Q: Discuss Theo in the context of three principles applied to every early treatment patient.1)
Growth and Development of the Craniofacial Complex
Background
An in‐depth understanding of craniofacial growth and development is essential to the practice of our specialty. Patients are often evaluated for early orthodontic intervention at a time when their facial skeleton and associated soft tissues are experiencing significant growth. Thus, foundational knowledge of post‐natal craniofacial growth, heritable and environmental influences on jaw growth and tooth development, and potential response of the growing jaws and teeth to intervention is crucial to provide effective early treatment to patients, and to assess early treatment outcomes. This section provides a brief review of important craniofacial growth and development concepts, with an emphasis on the facial skeleton, the airway, and the dentition. The development of other key soft tissues that support neural activity, respiration, mastication, and deglutition undoubtedly have an important influence on the growth and development of the facial skeleton. For more additional information on the growth and development of craniofacial soft tissues, the reader is referred to more comprehensive treatises on this subject [35–37].
Normal Skeletal Growth and Development, Abnormal Growth, and Growth Velocity
- Q: Do we have a complete understanding of the underlying mechanisms responsible for craniofacial growth and development?
A: Despite advances in our knowledge of craniofacial growth and development, a complete understanding of the underlying mechanisms has not yet been elucidated. The prevailing theory posits genetic control, whereby molecular signaling processes that dictate the temporal and spatial expression of key developmental genes, and environmental factors that modulate these control mechanisms operate in concert to influence craniofacial development [38]. The functional matrix hypothesis of Moss, a mechanistic description of the process of craniofacial growth and development, is the main conceptual framework understood by orthodontists [39, 40]. Future research on the genetic control theory will elucidate the mechanism of the functional matrix hypothesis. Comprehensive treatment of these concepts can be found elsewhere [39–44].
- Q: What is meant by craniofacial growth and development?
A: The term growth describes a change in size or quantity. In the context of craniofacial development, this occurs by cell proliferation leading to tissue enlargement. The term development describes changes in form and function based on changes in the specialization of cells, tissues, and organs [45].
- Q: What drives the growth and development of the craniofacial skeleton?
A: Growth and development of the craniofacial skeleton is under genetic control and modified by environmental factors. This growth control system mediates the specialization and enlargement of craniofacial skeletal tissue in concert with the specialization and enlargement of the tissues supporting neural activity, respiration, mastication, and deglutition. Craniofacial development is controlled by complex gene‐regulatory networks. For example, HOX and DLX genes are responsible for patterning of the vertebrate head in rostro‐caudal and dorso‐ventral axes, respectively [46]. Other key genes expressing transcription control factors and growth factors are responsible for mediating the growth, development, and maintenance of skeletal and soft tissues throughout embryogenesis and postnatal development [40, 42, 47].
- Q: In general terms, how does the facial skeleton grow?
A: The growing facial skeleton is a composite of cranial base growth, individual facial bone growth, and eruption and drift of the teeth. Each of these components has its own unique pattern of change, in space and time, driven by growth and development of associated key soft tissues and sensory organs. The unique shape and size characteristics of the facial skeleton are not generated independently. Change in size and shape of each growing facial bone is the result of complex genetic, spatial, temporal, and functional interrelationships among the essential functional components of the craniofacial region [41–43]. A composite of the growth and development changes for the cranial base and facial bones in the sagittal view is depicted in Figure 1.14.
- Q: What are the underlying osteogenic mechanisms responsible for facial bone size and shape changes?
A: Underlying osteogenic mechanisms include:
- Bone formation by both intramembranous and endochondral ossification.
- Intramembranous ossification is the mechanism for modeling and remodeling of the majority of the facial skeleton. Bone modeling drives spatial displacement of the cortical surfaces of intramembranous bone during which bone deposition and resorption of the periosteal and endosteal cortical surfaces occurs.
- Endochondral ossification replaces a cartilage template with bone. This is the mechanism for formation of the bony cranial base from the primary cartilage precursor. It is also the mechanism for growth of the condyle from adaptive secondary cartilage of the condyle.
- Bone modeling at the facial bone surfaces causing individual facial bone enlargement and change in shape. This is defined as facial bone surface drift.
- Bone modeling at the facial bone sutures coordinated with spatial displacement of investing functional tissues. This displacement is termed primary displacement of the facial bones and is often referred to as “sutural growth” of the craniofacial skeleton.
- Interstitial growth of cartilage in the synchondroses of the cranial base and nasal septal cartilage associated with spatial displacement of the adjoining bones of the face. Facial bone displacement by the enlargement and/or translation of adjoining facial bones is termed secondary displacement.
- Chondrogenesis and endochondral ossification of secondary cartilage of the mandibular condyle associated with primary displacement of the mandible.
With the possible exception of secondary displacement mediated by growth at synchondroses and the nasal septal cartilage, bone displacement and drift does not cause bones to “push” against each other. Facial bone displacement and drift is, by and large, mediated by biochemical and biomechanical signals during growth and development of the enveloping soft tissues [41, 42, 49].
The following questions provide a brief overview of the growth and development of the cranial base, the nasomaxillary complex, the mandible, and the airway. For more comprehensive reviews of these processes, we refer the reader to some excellent references [35, 47].
- Q: How does the cranial base grow? How does cranial base growth contribute to facial growth? Provide a detailed review.
A: The cranial base provides the foundation for postnatal facial development. In the midline, the cranial base undergoes lengthening by primary displacement to accommodate the growing brain. Frontal and temporal lobe brain expansion corresponds with the endochondral bone replacement of cartilage in the main growth centers of the cranial base, the spheno‐ethmoidal and spheno‐occipital synchondroses. Frontal and temporal lobe expansion also drives anterior and middle cranial fossae anteroposterior, vertical, and lateral enlargement via sutural growth and drift (see Figure 1.15). Details of cranial base spatial and temporal growth are found elsewhere [50].
The resulting forward movement of the anterior cranial base has a forward displacement (secondary) effect on the nasomaxillary complex. The forward growth of the anterior cranial base reaches adult dimension sooner than the posterior cranial base, reaching 90% of adult size by ~five years of age. The portion measured from sella turcica to foramen cecum ceases anteroposterior growth by ~seven years of age. Nasion continues forward growth through puberty influenced by expansion of the frontal sinus and, as some have suggested, growth of the nasal septal cartilage [51].
The pterygoid processes move downward by drift and displacement. As frontal lobe expansion and spheno‐ethmoidal synchondrosis growth cease (approximately age seven), temporal lobe expansion continues, displacing the frontal lobe anteriorly with a continued secondary displacement effect on the anterior cranial base and the nasomaxillary complex. Temporal lobe expansion laterally and vertically also influences the position of the glenoid fossae, which are displaced posteriorly and inferiorly until approximately age fifteen to sixteen years [52, 53], and to a greater degree during adolescence compared to childhood [54]. Numerous studies across different ethnic populations have shown that a more obtuse cranial base angle (angle formed by Nasion‐Sella and Sella‐Basion) and/or a long anterior (relative to posterior) cranial base length is associated with a skeletal Class II relationship. A more acute cranial base angle and/or a short anterior cranial base length is associated with a skeletal Class III relationship [55]. A composite of these growth movements in the sagittal view is depicted in Figure 1.16.
- Q: How does the nasomaxillary complex grow?
A: Growth expansion of the nasal septal cartilage, the investing soft tissues, and the airway displace the nasomaxillary complex downward and forward with primary displacement at the circummaxillary sutures adjoining the frontal, zygomatic, ethmoid, nasal, lacrimal, and palatine bones (see Figure 1.17).
Airway and soft‐tissue expansion directs bilateral displacements with growth at the intermaxillary sutures. In relative terms, the greatest amount of growth displacement of the nasomaxillary complex is displacement in vertical height, followed by displacement in anteroposterior depth, followed by displacement in transverse width [47]. Downward and forward growth of the anterior cranial base contributes early to nasomaxillary displacement, diminishing at ~ age seven, as continued displacement is directed by enlargement of the airway, investing soft tissue and the nasal septal cartilage [42, 51]. This is accompanied by backward downward drift at the posterior maxilla (tuberosity) with new bone available for eruption of permanent molar teeth and downward directed drift of the hard palate. Nasomaxillary surface drift occurs in response to changing soft tissue and facial bone spatial relationships. Palatal inferior drift and vertical drift of the maxillary permanent teeth contribute approximately 66% of the vertical height change in the maxilla [56, 57]. Vertical drift of maxillary teeth is controlled by forces of eruption (exact mechanism unknown) and forces opposing eruption (e.g. functional/parafunctional loading with mandibular teeth). A composite of these growth movements in the sagittal view is depicted in Figure 1.18.
The contribution of nasal septal cartilage interstitial growth to downward forward translation of the nasomaxillary complex remains controversial. Many believe the growth expansion of the nasal septal cartilage drives nasomaxillary downward and forward displacement [58–60]. Others believe the expansion of the nasal septal cartilage is adaptive to the functional demands directing the expansion of the airway according to the functional matrix hypothesis [61, 62]. Some authors have suggested the role of the nasal septum as a growth center is attenuated at the time the junction of the ethmoid and sphenoid bones transition from a cranial base growth center (synchondrosis) to a cranial base growth site (suture) [63].
- Q: How does the mandible grow?
A: The mandible is carried downward and forward by growth expansion of the enveloping soft tissues. In response, the mandible grows upward and backward largely by a combination of bone surface drift (intramembranous ossification) and primary displacement at the condyle (endochondral replacement of secondary cartilage).
- Q: The mandible consists of five developmentally important regions. What are they, and what role does each play?
A: The mandible consists of the condyle, coronoid process, ramus, corpus, and alveolar process (Figure 1.19). The role of each is as follows: [42]
- Condyle: along with the ramus, it is a major site of compensatory mandibular growth during downward and forward facial soft‐tissue expansion. It provides articulation with the temporal bone to mediate function between the maxillary and mandibular teeth. It performs these roles by virtue of the condylar cartilage, a specialized secondary cartilage allowing endochondral bone growth to occur in the presence of masticatory compressive forces on the condylar head. The arrangement of secondary cartilage allows condylar growth to be adaptive, facilitating change in growth direction as pressure and tension on the condylar head change, and to maintain the relationship of the condyle and glenoid fossa as the mandible is carried downward and forward.
- Coronoid process: provides attachment of the temporalis muscle, which supports the process of mastication. The coronoid process undergoes extensive drift upward, backward and laterally during the downward and forward translation of the mandible.
- Ramus: as a major site of adaptive growth and growth compensations, it is of equal importance to the condyle during downward and forward translation of the mandible. In order to maintain the appropriate spatial and functional relationship of the mandibular dentition with the maxillary dentition during growth, the ramus undergoes complex changes in width, depth, height, and uprighting (gonial angle becoming more acute). Although it is common to encounter the term “condylar growth,” signifying the condyle as the most important mandibular growth center, the importance of ramus growth is co‐equal in establishing balance or imbalance in mandibular position. Also, the ramus provides attachment for the masseter and medial pterygoid muscles.
- Corpus: supports the alveolar process and teeth during development and mastication; provides attachment for many muscles, include the mentalis muscle.
- Alveolar process: provides a bony housing for the eruption, drift, and function of teeth.
- Condyle: along with the ramus, it is a major site of compensatory mandibular growth during downward and forward facial soft‐tissue expansion. It provides articulation with the temporal bone to mediate function between the maxillary and mandibular teeth. It performs these roles by virtue of the condylar cartilage, a specialized secondary cartilage allowing endochondral bone growth to occur in the presence of masticatory compressive forces on the condylar head. The arrangement of secondary cartilage allows condylar growth to be adaptive, facilitating change in growth direction as pressure and tension on the condylar head change, and to maintain the relationship of the condyle and glenoid fossa as the mandible is carried downward and forward.
- Q: Describe the anatomy of the pharynx at birth, and the changes that occur during growth and development to adolescence.
A: In the newborn, the pharynx, uvula, and epiglottis are in proximity to allow the independent functions of suckling and breathing. During the period from approximately eighteen months of age until adolescence, vertical growth causes the relative descent of the larynx, increasing the cumulative vertical length of the nasopharynx, oropharynx, and laryngopharynx twofold from ~7–8 mm to ~15–16 mm, ultimately stretching vertically between the sphenoid bone superiorly and the level of the fifth cervical vertebrae inferiorly (Figure 1.20) [64, 65