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Orthodontic Treatment in the Primary Dentition
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Orthodontic Treatment in the Primary Dentition JOHN R. CHRISTENSEN
CHAPTER OUTLINE Skeletal Problems Dental Problems Arch Length Problems Incisor Protrusion and Retrusion Posterior Crossbite Open Bite
T
he goals of orthodontic care in the primary dentition should be to treat conditions that predispose one to develop a malocclusion in the permanent dentition or to monitor conditions that are best treated later.1 Some primary dentition problems can be effectively managed, and the result provides a long-term benefit. With other conditions, treatment should be deferred until intervention can provide a long-term benefit. The clinician needs to differentiate skeletal problems from dental to fulfill these goals. Treatment of skeletal malocclusions in this age group is ordinarily deferred until a later age; the delay is generally for practical reasons rather than an inability to alter skeletal structure at this age. Three general reasons are offered for delaying treatment. First, the diagnosis of skeletal malocclusion is difficult in this age group. Subtle gradations of skeletal problems and immature soft tissue development make clinical diagnosis of all but the most obvious cases difficult. Second, although the child is growing at this stage, the amount of facial growth remaining when the child enters the mixed dentition years is sufficient to aid in the correction of most skeletal malocclusions. Third, any skeletal treatment at this age requires prolonged retention because the initial growth pattern tends to reestablish itself when treatment is discontinued. In essence, retention is active treatment over a sustained period of years to maintain the correction. On the other hand, several dental problems merit attention during the primary dentition years. This chapter is devoted to these issues.
Skeletal Problems Skeletal problems are addressed only if there is progressive asymmetry due to a functional disturbance.2 The reason for treating these 394
patients early is that treatment at a later time may be more difficult and complex if the child continues to grow asymmetrically and dental compensation increases. The goal of early treatment is to prevent the asymmetry from becoming worse or to alter growth so the asymmetry improves. Most progressive asymmetry patients are treated with removable functional appliances designed to alter growth by manipulating skeletal and soft tissue relationships and allowing differential eruption of teeth. Orthognathic surgery is a second treatment option for progressive asymmetry but is reserved for patients with severe asymmetry or those whose condition does not respond to functional appliance therapy. It may be necessary to operate a second time when the child is older because growth often tends to remain asymmetric even after surgical correction. Because diagnosis and treatment of progressive asymmetry are difficult, it is recommended to refer these cases to a specialist for evaluation and treatment. Early evaluation of patients with dentofacial anomalies is also advocated. Dentofacial anomalies include several environmentally and genetically induced conditions that alter the relationship of the facial structures. Examples include cleft lip and palate, hemifacial microsomia, Crouzon and Apert syndromes, and mandibulofacial dysostosis (Treacher Collins syndrome). A specialist or specialty team works to minimize the facial disfigurement through early surgical and orthodontic intervention.
Dental Problems Selected dental malocclusion in the primary dentition is readily managed by the practitioner who has knowledge of fixed and removable appliances. The key to successful orthodontic management is careful diagnosis and treatment planning. A comprehensive database should be obtained. In this age group, tooth movement usually is restricted to tipping teeth into proper position as in anterior crossbite correction. Rarely are orthodontic appliances indicated to move teeth bodily, but posterior crossbite correction is one of those. Before specific treatment problems are discussed, the biology of tooth movement should be briefly reviewed. Two theories of tooth movement have been proposed to describe the mechanism of movement. The first is the “pressure-tension” theory. A force applied to a tooth causes alterations in the periodontal ligament and surrounding alveolar bone. This pressure creates reduced blood flow within the periodontal ligament, leading to limited cellular activity and disorganization of the ligament. On the tension side
CHAPTER 28 Orthodontic Treatment in the Primary Dentition
the stretching of fibers creates an increase in cellular activity resulting in elevated fiber production.3 The pressure-tension theory is based on histologic studies of the periodontium. During the early stages of compression or pressure, cell-free zones are created (hyalinization). The body reacts to the hyalinization by recruiting macrophages, foreign body giant cells, and osteoclasts from nearby undamaged areas. These cells resorb the bone adjacent to the hyalinized periodontal ligament. The term used to describe this process is undermining resorption. The osteoblast also plays a significant role in tooth movement. In the area of periodontal ligament tension, osteoblasts begin to enlarge and produce new bone matrix. Other preosteoblasts are recruited to aid in bone deposition. Together, the cells work to break down the necrotic tissue and matrix on the pressure side of the tooth and build new bone and structure on the side of tension. The second theory of tooth movement suggests that a force applied to a tooth is spread equally to all regions of the periodontal ligament. The alveolar bone is deflected, and this begins the changes seen in the periodontal ligament. This is called the bone-bending theory. Forces applied to teeth will bend bone, tooth, and solid structures of the periodontal ligament. Bone is far more elastic than the other tissues, so when bone is held in a deformed position bone turnover and production are initiated. The force applied to the tooth is dissipated within the bone by production of stress lines within the area of force application. Continuous force application like that delivered by an orthodontic appliance becomes a stimulus for cells to alter their normal activities. This altered activity modifies the shape and internal organization of the bone to accommodate these forces. After force application, the tooth will move approximately the width of the periodontal ligament or until the hyalinization begins. After this small movement, the tooth will not move again for some 4 to 20 days. Movement will not occur until removal of the necrotic tissue is complete and bone resorption, both direct (from periodontal ligament) and indirect (adjacent marrow spaces), has occurred. When the tooth has moved a certain distance, the force exerted by the orthodontic appliance diminishes to an amount below that necessary for tooth movement. During this time, remodeling is completed and the periodontal ligament and alveolar bone cells begin to return to their normal state. This reorganization period is necessary to prevent injury to the tooth and supporting structures. The clinical implication of cellular change, tooth movement, and cellular reorganization is that orthodontic appliances should be reactivated only at 4- to 6-week intervals with a light, continuous force to avoid injury to the periodontium. There is some biological basis for the recommendation of monthly visits during orthodontic treatment. After tooth movement is complete, the patient enters the retention phase of treatment. Retention is the time period the teeth are held in their new position. Retention is necessary because teeth that have been moved orthodontically tend to move back or relapse into their original position after the appliance has been removed. Relapse may be due to many factors; however, gingival changes seem to be the primary factor. The gingival tissue does not regain its pretreatment shape like bone and periodontal ligament. The gingiva contains a network of gingival fibers that are compressed or stretched during tooth movement. The genes of both collagen and elastin are activated, and tissue collagenase is inhibited. This causes the extracellular matrix of the gingiva to become more elastic and at greater risk for relapse. Reorganization of the gingival tissues most likely requires a full year. Surgical treatment such as a gingival fibrotomy has been shown to increase stability, indicating
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the role of gingival fibers in relapse.4 This type of procedure is not performed in the primary dentition but may be required in the mixed or permanent dentitions. If surgical treatment is not performed, long-term retention is indicated to prevent relapse.5 Other factors also influence postorthodontic tooth movement. Pressure from the orofacial musculature, postorthodontic facial growth, and the interdigitation of the teeth (or lack of ) has been reported to contribute to orthodontic instability.6
Arch Length Problems The most common arch length problem in the primary dentition is tooth loss. This is managed as outlined in Chapter 26 with space maintenance if the space is adequate. If space has been lost because of tooth loss, space regaining can be instituted. A notable situation in which to use space regaining is when the primary first molar is lost prematurely. The only realistic space regaining in the primary dentition is repositioning the primary second molar before the permanent first molar erupts. A removable appliance is best used for this purpose. A primary second molar can be repositioned approximately 1 mm per month using a removable appliance with multiple clasps and a finger spring (Fig. 28.1). Three millimeters of molar movement is a realistic extent of the treatment. The appliance is similar to the appliance used to reposition a permanent first molar. If a second primary molar is lost, timely placement of a distal shoe is required, to prevent space loss with the eruption of the permanent first molar. Although inviting and seemingly intuitive, there is little relationship between the arch length (arch perimeter) in the primary and permanent dentitions.7 This means that weak correlations do not support the early interventions advocated by some and described here. Early intervention is expanding the primary arches with either a fixed or a removable appliance. This treatment is provided to ensure space for the permanent teeth.8 The expansion provides variable increases in arch width and arch perimeter and is associated with little long-term benefit.9 This early approach to potential crowding remains controversial and unsubstantiated. It is also important to remember there is a potential to treat up to 4.5 mm of crowding in the late mixed dentition simply with the use of a passive lower lingual arch.10
• Figure 28.1 This appliance was designed to move the right molar distal. Note there are two retentive clasps to hold the appliance in place. The appliance would dislodge as the spring was activated without retention. This type of appliance can move a molar approximately 3 mm.
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Incisor Protrusion and Retrusion In addressing the anteroposterior plane of space, the clinician is mainly concerned with the position of the incisors, particularly the maxillary incisors. The majority of anteroposterior problems involve anterior crossbite, a condition in which the maxillary incisors occlude lingual to the mandibular incisors. A fixed lingual arch or a removable appliance can be used to correct the crossbite, but several things should be kept in mind when moving primary anterior teeth. First, the crowns are extremely short incisogingivally. This means overly aggressive activation of springs will cause them to slip down the lingual surface and not engage the crowns of the teeth. It is best to activate the springs in a facial and gingival direction with gentle activation. Second, the crowns of some primary first molars converge toward the occlusal surface. This makes banding or clasp retention challenging. Third, there are few or no undercuts on the anterior teeth that will engage a labial bow for retention. For this reason, if a labial bow in the primary dentition is not used for tooth movement, it probably should be discarded from the appliance prescription. Finally, because the primary teeth will be exfoliated near 6 to 7 years of age, it is not wise to consider moving a primary incisor much after 4 years of age. Because compliance can be a problem before age 4 years and because primary root resorption and tooth morphology are problems after age 4, few clinicians attempt treatment for anterior crossbites in the primary dentition. If crossbite correction is indicated, a maxillary lingual arch can be designed to push directly on the incisors with reasonably heavy force (0.036-inch wire) or the lingual arch can have lighter forces delivered with attached finger springs (0.022-inch wire). Either way, the arch can be activated to tip maxillary teeth into proper position. The lingual arch is activated approximately 1 mm per visit because it is a heavy-gauge wire that exerts a heavy force. The auxiliary wires can be activated 2 mm (Fig. 28.2). In general, a tooth moves 1 mm per month during treatment. Therefore, if a tooth requires 3 mm of movement to be properly aligned, 3 months of treatment is necessary. With a removable appliance, wire finger springs are incorporated into the palatal acrylic to move the teeth facially. Placing retentive clasps on the posterior teeth stabilizes the appliance. The finger springs are activated 1.5 to 2.0 mm per month. If the patient exhibits a positive overbite and overjet after treatment, retention is probably not necessary because the occlusion generally holds
the tipped incisor in its new position. If there is no overbite, the appliance should be maintained until overbite is established to ensure that relapse does not occur. The decision to correct an anterior crossbite in the primary dentition is a difficult one. The clinician should determine if the crossbite is skeletal or dental in nature. Other factors to consider are the number of teeth involved, the presence of a mandibular shift, and the age of the patient. There are few evidence-based studies to support or refute correction of a dental anterior crossbite in the primary dentition. In other words, would the crossbite self-correct with the exchange of the permanent incisors? Or, does the early correction maintain itself when the permanent incisors erupt? There are hints that self-correction is possible in dental causes of anterior crossbite.11–13 One further point should be made about anterior crossbite. In some cases of posterior crossbite or occlusal interference, a child positions the jaw forward (known as a mandibular shift) to achieve maximal intercuspation and an anterior crossbite results (usually called a pseudo class III malocclusion because the patient is often class I and shifts into a class III position). In this situation the patient positions the lower jaw forward only to obtain comfortable intercuspation as needed to function. This type of anterior crossbite is due to jaw posturing rather than tooth or jaw malposition. In these cases, treatment is directed to the posterior crossbite or the occlusal interference and not to the anterior crossbite. In some cases the interfering tooth is the one in crossbite. Excessive overjet in the primary dentition is usually due to a nonnutritive sucking habit or to a skeletal mismatch between the upper and lower jaws. Most skeletal problems should not be treated at this time because of the tendency for abnormal growth patterns to recur. However, incisor protrusion as a result of a sucking habit can be addressed. Treatment is usually directed at eliminating the habit rather than correcting the incisor protrusion. Incisor protrusion usually corrects itself or is significantly reduced if the habit is discontinued and if the equilibrium between the tongue, lips, and perioral musculature is reestablished. The quad helix, palatal crib, and Bluegrass appliance are discussed in Chapter 27 and are the appliances of choice for habit therapy (see Figs. 27.6 to 27.8). Studies designed to determine how long the appliance must remain in place to terminate the habit effectively suggest a 6-month minimum.14 The key to treatment is whether the patient and the parents both want to have the patient stop the habit. If one or neither is interested in discontinuing the habit, it is best to delay treatment until they are ready.
Posterior Crossbite
• Figure 28.2
This patient’s anterior crossbite involving the primary maxillary central incisors is being treated with a T spring soldered to a lingual arch. The spring is activated 1 to 2 mm per month until the incisors are tipped out of crossbite.
Posterior crossbite in the primary dentition is usually a result of constriction of the maxillary arch. Constriction often results from an active digit or pacifier habit, although there are many cases in which the origin of the crossbite is undetermined. The first step in managing a posterior crossbite is to establish whether there is an associated mandibular shift. If a mandibular shift is present, treatment generally should be implemented to correct the crossbite. Some authors have implicated a mandibular shift as the cause of asymmetric growth of the mandible.15 The asymmetry is thought to occur because the condyles are positioned differently within each fossa. Muscle and soft tissue stretch exert forces on the underlying skeletal and dental structures that may alter normal growth and arch development. If no shift is detected, the mandible should grow symmetrically. It has been suggested to wait on treatment until the permanent molar erupts if there is no mandibular
CHAPTER 28 Orthodontic Treatment in the Primary Dentition
shift.12 After the permanent molar erupts, the clinician can treat if it erupts in crossbite or continue to observe if there is no permanent molar crossbite or mandibular shift. There are two basic approaches to the management of posterior crossbite in young children: (1) equilibration to eliminate mandibular shift and (2) expansion of the constricted maxillary arch. In a few cases the mandibular shift is due to interference caused by the primary canines. These cases can be diagnosed by repositioning the mandible and noting the interference. Selective removal of enamel with a diamond bur in both arches eliminates the interference and the lateral shift into crossbite. This type of treatment has evidenced-based support.16 In cases of bilateral maxillary constriction, expansion is recommended to correct the lateral shift. This situation should be managed as soon as it is diagnosed unless the permanent first molar is expected to erupt within 6 months. If permanent molar eruption is imminent, it is better to allow the permanent molars to erupt and incorporate these teeth into treatment if necessary. Both fixed and removable appliances can be designed to correct maxillary constriction, although fixed appliances are reliable and require little patient cooperation. A randomized prospective study of unilateral crossbite correction in the mixed dentition suggested the most successful intervention was with fixed appliances.17 Fixed appliances are variations of a lingual arch bent into the shape of a W. In fact, one of the most popular appliances used to treat crossbites is named the “W arch” (Fig. 28.3). Another
• Figure 28.3
The W arch is a fixed appliance used to correct posterior crossbites in the primary dentition.
A
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popular appliance is the quad helix (see Fig. 27.6). The W arch is constructed of 0.036-inch wire that rests 1.0 to 1.5 mm off the palate to prevent soft tissue irritation. The W arch is expanded approximately 4 to 6 mm wider than its passive width, or so that one arm of the W is resting over the central grooves of the teeth when the other arm is seated. To move teeth preferentially in the anterior region of the mouth, the appliance is activated by bending the palatal portion of the arm near the solder joint, as demonstrated in Fig. 28.4. If more correction is needed in the molar region, the appliance is activated via bending of the anterior palatal portion. The appliance expands the arch approximately 1 mm per side per month. The patient should return monthly to allow the dentist to check the progress of treatment and to reactivate the W arch if needed. The appliance can be activated intraorally by squeezing the wire with a three-pronged plier, although the force and direction of activation may be difficult to approximate, and unwanted tooth movement can result. Usually it is easier and more accurate to remove, activate, and recement the appliance. Expansion should continue until the crossbite is slightly overcorrected and the lingual cusps of the maxillary teeth occlude on the lingual inclines of the buccal cusps of the mandibular teeth. Most crossbites are corrected in 3 months, and the teeth are retained for an additional 3 months. The quad helix is designed much like the W arch but incorporates more wire into the appliance, making it more flexible. It is constructed of 0.038-inch wire with two helices in the anterior palate and two helices near the solder joint in the posterior palate. The helices are wound away from the palate and can serve to remind the digit-sucking patient to refrain from the habit if they are positioned correctly where the patient places the finger or thumb. Therefore this is the preferred appliance for a patient with a finger habit and posterior crossbite. Because the quad helix has more wire than the W arch, it has a greater range of action and can be activated farther than the W arch while delivering an equivalent amount of force. Overcorrection and retention are also required for the quad helix. Despite activation of the W arch or quad helix on one side only, teeth on both sides of the arch react to equivalent force. These types of fixed lingual arch type appliances have been shown to produce both skeletal and dental changes in the primary and mixed dentitions.17
B • Figure 28.4 (A) The W arch can be activated in two spots. (B) The preferred way to move teeth in the anterior region of the mouth is to activate the W arch by bending the arm of the W in the area marked location 1. Continued
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C
D • Figure 28.4, cont’d
(C) If the clinician wants to obtain more movement in the molar region, the appliance is activated by bending the anterior portion of the W in the area marked location 2. (D) In general, the appliance is activated 3 to 4 mm beyond its passive width or to a position where one arm of the W extends over the central grooves of the teeth when the other arm is seated in place.
Open Bite Vertical problems in the primary dentition usually are due to a finger or pacifier habit, and they result in an anterior open bite. Treatment for an anterior open bite that is due to a sucking habit is discussed in Chapter 27. Deep bite in the primary dentition is generally not corrected at this time. The depth of bite usually improves with the eruption of the permanent first molars if the problem is the result of dental malocclusion.
References 1. Ngan P, Fields HW. Orthodontic diagnosis and treatment planning in the primary dentition. J Dent Child. 1995;62:25–33. 2. Proffit WR, Fields HW, Sarver DM. Treatment of skeletal problems in children. In: Contemporary Orthodontics. 5th ed. St Louis: Mosby; 2012. 3. Kishnan V, Davidovitch Z. Cellular, molecular, and tissue-level reactions to orthodontic force. Am J Orthod. 2005;129:469.e1–469. e32. 4. Redlich M, Shoshan S, Palmon A. Gingival response to orthodontic force. Am J Orthod Dentofacial Orthop. 1999;116:152–157. 5. Lang G, Alfter G, Göz G, et al. Retention and stability—taking various treatment parameters into account. J Orofacial Orthop. 2002;63:26–41. 6. Melrose C, Millett DT. Toward a perspective on orthodontic retention? Am J Orthod Dentofacial Orthop. 1998;113(5):507–514. 7. Bishara SE, Khadivi P, Jakobsen JR. Changes in tooth size–arch length relationships from the deciduous to the permanent dentition:
a longitudinal study. Am J Orthod Dentofacial Orthop. 1995;108: 607–613. 8. McInaney JB, Adams RM, Freeman M. A nonextraction approach to crowded dentitions in young children: early recognition and treatment. J Am Dent Assoc. 1980;101:251–257. 9. Lutz HD, Poulton D. Stability of dental arch expansion in the deciduous dentition. Angle Orthod. 1985;55:299–315. 10. Gianelly AA. Treatment of crowding in the mixed dentition. Am J Orthod Dentofacial Orthop. 2002;121:569–571. 11. Nagahara K, Murata S, Nakamura S, et al. Prediction of the permanent dentition in deciduous anterior crossbite. Angle Orthod. 2001;71(5): 390–395. 12. Dimberg L, Lennartsson B, Arnrup K, et al. Prevalence and change of malocclusions from primary to early permanent dentition: a longitudinal study. Angle Orthod. 2015;85:728–734. 13. Nagahara K, Suzuki T, Nakamura S. Longitudinal changes in the skeletal pattern of deciduous anterior crossbite. Angle Orthod. 1997;67(6):439–446. 14. Haryett RD, Hansen FC, Davidson PO. Chronic thumb-sucking. A second report on treatment and its psychological effects. Am J Orthod. 1970;57:164–178. 15. Primozic J, Richmond S, Kau CH, et al. Three-dimensional evaluation of early crossbite correction: a longitudinal study. Eur J Orthod. 2011;35(1):7–13. 16. Harrison JE, Ashby D. Orthodontic treatment for posterior crossbites. Cochrane Database Syst Rev. 2001;(1):CD000979. 17. Petrén S, Bondemark L. Correction of unilateral posterior crossbite in the mixed dentition: a randomized controlled trial. Am J Orthod Dentofacial Orthop. 2008;133(6):e790–e797.
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Case Study: Orthodontics for the Child With Special Needs John R. Christensen Similar to the general population, children with special needs exhibit varying malocclusions. Many of the malocclusions are found in the general population; however, there seems to be a higher prevalence of severe malocclusion in individuals with physical and mental disabilities. The higher prevalence is explained by abnormal orofacial musculature (abnormal tongue position), craniofacial anomalies, genetics (Down syndrome), and brain injuries (cerebral palsy).1 Each has a malocclusion characteristic of the specific developmental problem. Studies of children with autism spectrum disorder (ASD) have reported mixed findings. One did not find any difference in the Dental Aesthetic Index, a measure of malocclusion severity.2 Another reported children with ASD had an increased prevalence of posterior crossbite, increased overjet, and maxillary crowding.3 Parents inquire about treatment of malocclusion for their child with special needs. Studies have indicated they have a high level of motivation for treatment and are willing to participate in oral hygiene practices.4,5 Parents report the number one reason for orthodontic treatment is to improve facial appearance. Their expectations (and hopes) are that treatment will improve the child’s quality of life, role in society, and his or her social acceptance. The dentist’s role in treating the child with special needs is to discuss orthodontic treatment with the parents and patient. Actually, the clinician should be more of an active listener to determine parent and patient concerns. After discussing the need and motivation for treatment, the clinician should consider whether treatment seems reasonable, is achievable, and promises some stability. Each child needs to be evaluated on an individual basis. Some will be good candidates. Other patients could benefit from orthodontics, but because of the disability, care will be difficult and may not be stable.6
Behavior Every child has some innate ability to cooperate with treatment. The dentist must consider how much ability is within the child to cooperate. Oftentimes, behavior can be guided to examine the teeth only, whereas other times the patient may allow complete dental care. Several questions should be considered. Can the child physically sit for appliance placement? Will the child allow appliances to be placed? Will the appliance cause gagging or difficulty eating? Can the child clean the appliances so the teeth are not put at risk during treatment? Oftentimes these questions can be answered prior to the start of treatment, but there are times when the limits of cooperation are not known. In general, the clinician can determine a patient’s ability to cooperate during the records appointment. The clinician can assess whether a patient will follow directions or is cooperative for procedures such as radiographs and photographs. Does the child gag? Can the gag reflex be managed? Even something as simple as moving the dental chair can startle a child with special needs. Staff need to be trained and encouraged to deliver care in multiple ways. For example, the chair may not be completely reclined, the dental light may not be used, or the patient may need to sit up to drink water from a cup rather than being rinsed with an air/water syringe and suction. The clinician should note patient behaviors as the records are obtained. If records are difficult or impossible to obtain, orthodontic treatment may be just as difficult. Appointment scheduling should be adapted to the individual child. Often a series of desensitization appointments are necessary to acclimate the child to the orthodontic world. Different chairs, different staff, and different doctors are just some of the challenges for a child with special needs. It is helpful to schedule care in the same chair with the same staff so the child has some ability to anchor his or her care from appointment to appointment. The time for each appointment should be adjusted to accommodate the child. The typical time for an orthodontic procedure may be twice as long for the patient with special needs.
Patient’s Ability to Tolerate the Appliance After records, the clinician presents a problem list and treatment plan to the family. The dentist should determine from the records appointment or from discussion with the parent whether the patient can tolerate orthodontic appliances. Often it is prudent to place limited orthodontic appliances on the teeth (in a passive state) to determine if the patient can tolerate the appliances. After it is established the child can tolerate the appliances, additional appliances can be added. For example, in a case requiring upper and lower arch treatment, the clinician may place brackets on the upper front teeth. This is an area that is easy to access for placement and removal if necessary. If the child does well with this treatment, additional brackets can be placed on the lower arch or the upper posterior teeth. Appliance placement is staged so the clinician can terminate treatment without creating a situation in which work must continue to get the teeth into a stable position. The most obvious example of staged treatment is tooth removal. It is wise to start appliances prior to tooth removal even if there is no room to move teeth until extractions have been performed. After it is apparent the patient will tolerate appliances, the teeth can be removed. If teeth are removed first and the patient is not a good candidate for treatment, the patient can end up with an even worse situation. If a removable appliance is being considered, one can construct a sham appliance or deliver the actual appliance without activation. Children can be overwhelmed by a removable appliance, so it is important to introduce it slowly. The patient can be asked to wear the appliance on day 1 for one-half hour. Each day another increment of wear can be added until the targeted time is achieved. If the appliance is intended for night wear, it can be helpful to start the appliance during waking hours. The patient can develop confidence in the appliance before attempting to sleep with it at night.
Patient’s Ability to Cooperate With the Treatment Plan Cooperation in treatment is as important in a child with special needs as it is in a normal child. The clinician should be prepared to modify the plan or the intended treatment based on the individual’s ability to cooperate. This can mean extended chair time to allow the child time to feel comfortable and receive care. It can mean proposed treatment for the day will be postponed due to the child’s inability to cooperate or receive treatment on that particular day. Staff must be trained to deliver care in a manner different than normal. For example, tooth-brushing instructions will vary if a child has a physical difference that prevents a normal brushing stroke. A different technique, a different toothbrush, or another individual must be used to provide good home care. A child with a sensory disorder may not be able to tolerate the taste of materials used to prepare teeth. It may be necessary to use a different material. The key is flexibility for the clinician and staff. The rule is there are no rules to treatment approach.
Stability of Results As with children without disabilities, the clinician needs to consider several variables in the retention plan. The orthodontic literature is full of questions about retention and the stability of tooth movement. In a patient with special needs, the clinician should consider several issues. Will the patient be able to tolerate an appliance? Will the patient wear the appliance? Is a fixed retainer a better option for retention? Will oral hygiene be more difficult with a fixed retainer? Will a patient (with a sensory disorder) tolerate the taste or texture of a retainer? In cases of patients with muscular issues (cerebral palsy), retention appropriate for a normal child may not work due to the difference in muscle activity or may not be tolerated due to swallowing and drooling difficulties. There are an unlimited number of issues to consider in retention, and it is nearly impossible to anticipate every one. The clinician must be well versed in orthodontic retention and the literature. Each patient requires an individual retention plan based on the special need of the patient. Continued
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Questions 1. What barriers to orthodontic care do children with special needs face? Answer: The child with special needs faces several barriers to care. The first is finding a dentist who is trained and comfortable with treating children with different needs. The second is similar to the first, and that is finding a dentist who participates in Medicaid and other programs designed to help these children. Reimbursement rates are lower in these programs, and many dentists choose not to participate due to the rates. Children with special needs have mental and physical disabilities that may interfere with the delivery of orthodontic care. 2. Describe ways a dentist can measure if a child with special needs will tolerate orthodontic care? Answer: The first answer to this question is how the child does with general dental care. If the patient is cooperative and maintains good oral health, the child will typically do well for orthodontic care. If the child requires extra guidance during regular care, the clinician should anticipate more guidance will be needed for orthodontic care. A stepwise progression is often appropriate to determine the child’s tolerance for care. Orthodontic appliances can be introduced slowly and placed without activation (teeth will not move) just to determine how the child will do with orthodontic appliances. If the child is doing well, the appliance can be activated to move teeth or more appliances can be added. If the child is not doing well with orthodontic care, the limited appliances can be removed without harm to the patient. 3. List five ways orthodontic care may be different for a child with special needs. Answer: • Appointment lengths may be longer to accommodate the child’s special needs.
• Treatment plans may be less comprehensive and more flexible due to several unknown factors relating to each child’s special needs. • Treatment is staged so if a child cannot tolerate treatment, discontinuing treatment will not result in leaving the patient in a worse condition than the start. • Materials may need to be varied depending on the sensitivities of the patient. This may be a result of multiple allergies or just a sensitivity disorder to a certain taste or texture. • The clinician and staff may vary from the scheduled treatment for the day depending on the disposition of the patient and the ability of the patient to tolerate treatment that day. There is a much greater range of behaviors to negotiate in the child with special needs.
References 1. Rada R, Bakhsh HH, Evans C. Orthodontic care for the behavior-challenged special needs patient. Spec Care Dentist. 2015;35(3):138–142. 2. Luppanapornlarp S, Leelataweewud P, Putongkam P, et al. Periodontal status and orthodontic treatment need of autistic children. World J Orthod. 2010;11(3):256–261. 3. Fontaine-Sylvestre C, Roy A, Rizkallah J, et al. Prevalence of malocclusion in Canadian children with autism spectrum disorder. Am J Orthod Dentofacial Orthop. 2017;152(1):38–41. 4. Abeleira MT, Pazos E, Ramos I, et al. Orthodontic treatment for disabled children: a survey of parents’ attitudes and overall satisfaction. BMC Oral Health. 2014;14(1):98. 5. Becker A, Shapira J, Chaushu S. Orthodontic treatment for the special needs child. Prog Orthod. 2009;10(1):34–47. 6. Becker A, Shapira J, Chaushu S. Orthodontic treatment for disabled children: motivation, expectation, and satisfaction. Eur J Orthod. 2000;22(2):151–158.
Orthodontic Treatment in the Primary Dentition JOHN R. CHRISTENSEN
CHAPTER OUTLINE Skeletal Problems Dental Problems Arch Length Problems Incisor Protrusion and Retrusion Posterior Crossbite Open Bite
T
he goals of orthodontic care in the primary dentition should be to treat conditions that predispose one to develop a malocclusion in the permanent dentition or to monitor conditions that are best treated later.1 Some primary dentition problems can be effectively managed, and the result provides a long-term benefit. With other conditions, treatment should be deferred until intervention can provide a long-term benefit. The clinician needs to differentiate skeletal problems from dental to fulfill these goals. Treatment of skeletal malocclusions in this age group is ordinarily deferred until a later age; the delay is generally for practical reasons rather than an inability to alter skeletal structure at this age. Three general reasons are offered for delaying treatment. First, the diagnosis of skeletal malocclusion is difficult in this age group. Subtle gradations of skeletal problems and immature soft tissue development make clinical diagnosis of all but the most obvious cases difficult. Second, although the child is growing at this stage, the amount of facial growth remaining when the child enters the mixed dentition years is sufficient to aid in the correction of most skeletal malocclusions. Third, any skeletal treatment at this age requires prolonged retention because the initial growth pattern tends to reestablish itself when treatment is discontinued. In essence, retention is active treatment over a sustained period of years to maintain the correction. On the other hand, several dental problems merit attention during the primary dentition years. This chapter is devoted to these issues.
Skeletal Problems Skeletal problems are addressed only if there is progressive asymmetry due to a functional disturbance.2 The reason for treating these 394
patients early is that treatment at a later time may be more difficult and complex if the child continues to grow asymmetrically and dental compensation increases. The goal of early treatment is to prevent the asymmetry from becoming worse or to alter growth so the asymmetry improves. Most progressive asymmetry patients are treated with removable functional appliances designed to alter growth by manipulating skeletal and soft tissue relationships and allowing differential eruption of teeth. Orthognathic surgery is a second treatment option for progressive asymmetry but is reserved for patients with severe asymmetry or those whose condition does not respond to functional appliance therapy. It may be necessary to operate a second time when the child is older because growth often tends to remain asymmetric even after surgical correction. Because diagnosis and treatment of progressive asymmetry are difficult, it is recommended to refer these cases to a specialist for evaluation and treatment. Early evaluation of patients with dentofacial anomalies is also advocated. Dentofacial anomalies include several environmentally and genetically induced conditions that alter the relationship of the facial structures. Examples include cleft lip and palate, hemifacial microsomia, Crouzon and Apert syndromes, and mandibulofacial dysostosis (Treacher Collins syndrome). A specialist or specialty team works to minimize the facial disfigurement through early surgical and orthodontic intervention.
Dental Problems Selected dental malocclusion in the primary dentition is readily managed by the practitioner who has knowledge of fixed and removable appliances. The key to successful orthodontic management is careful diagnosis and treatment planning. A comprehensive database should be obtained. In this age group, tooth movement usually is restricted to tipping teeth into proper position as in anterior crossbite correction. Rarely are orthodontic appliances indicated to move teeth bodily, but posterior crossbite correction is one of those. Before specific treatment problems are discussed, the biology of tooth movement should be briefly reviewed. Two theories of tooth movement have been proposed to describe the mechanism of movement. The first is the “pressure-tension” theory. A force applied to a tooth causes alterations in the periodontal ligament and surrounding alveolar bone. This pressure creates reduced blood flow within the periodontal ligament, leading to limited cellular activity and disorganization of the ligament. On the tension side
CHAPTER 28 Orthodontic Treatment in the Primary Dentition
the stretching of fibers creates an increase in cellular activity resulting in elevated fiber production.3 The pressure-tension theory is based on histologic studies of the periodontium. During the early stages of compression or pressure, cell-free zones are created (hyalinization). The body reacts to the hyalinization by recruiting macrophages, foreign body giant cells, and osteoclasts from nearby undamaged areas. These cells resorb the bone adjacent to the hyalinized periodontal ligament. The term used to describe this process is undermining resorption. The osteoblast also plays a significant role in tooth movement. In the area of periodontal ligament tension, osteoblasts begin to enlarge and produce new bone matrix. Other preosteoblasts are recruited to aid in bone deposition. Together, the cells work to break down the necrotic tissue and matrix on the pressure side of the tooth and build new bone and structure on the side of tension. The second theory of tooth movement suggests that a force applied to a tooth is spread equally to all regions of the periodontal ligament. The alveolar bone is deflected, and this begins the changes seen in the periodontal ligament. This is called the bone-bending theory. Forces applied to teeth will bend bone, tooth, and solid structures of the periodontal ligament. Bone is far more elastic than the other tissues, so when bone is held in a deformed position bone turnover and production are initiated. The force applied to the tooth is dissipated within the bone by production of stress lines within the area of force application. Continuous force application like that delivered by an orthodontic appliance becomes a stimulus for cells to alter their normal activities. This altered activity modifies the shape and internal organization of the bone to accommodate these forces. After force application, the tooth will move approximately the width of the periodontal ligament or until the hyalinization begins. After this small movement, the tooth will not move again for some 4 to 20 days. Movement will not occur until removal of the necrotic tissue is complete and bone resorption, both direct (from periodontal ligament) and indirect (adjacent marrow spaces), has occurred. When the tooth has moved a certain distance, the force exerted by the orthodontic appliance diminishes to an amount below that necessary for tooth movement. During this time, remodeling is completed and the periodontal ligament and alveolar bone cells begin to return to their normal state. This reorganization period is necessary to prevent injury to the tooth and supporting structures. The clinical implication of cellular change, tooth movement, and cellular reorganization is that orthodontic appliances should be reactivated only at 4- to 6-week intervals with a light, continuous force to avoid injury to the periodontium. There is some biological basis for the recommendation of monthly visits during orthodontic treatment. After tooth movement is complete, the patient enters the retention phase of treatment. Retention is the time period the teeth are held in their new position. Retention is necessary because teeth that have been moved orthodontically tend to move back or relapse into their original position after the appliance has been removed. Relapse may be due to many factors; however, gingival changes seem to be the primary factor. The gingival tissue does not regain its pretreatment shape like bone and periodontal ligament. The gingiva contains a network of gingival fibers that are compressed or stretched during tooth movement. The genes of both collagen and elastin are activated, and tissue collagenase is inhibited. This causes the extracellular matrix of the gingiva to become more elastic and at greater risk for relapse. Reorganization of the gingival tissues most likely requires a full year. Surgical treatment such as a gingival fibrotomy has been shown to increase stability, indicating
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the role of gingival fibers in relapse.4 This type of procedure is not performed in the primary dentition but may be required in the mixed or permanent dentitions. If surgical treatment is not performed, long-term retention is indicated to prevent relapse.5 Other factors also influence postorthodontic tooth movement. Pressure from the orofacial musculature, postorthodontic facial growth, and the interdigitation of the teeth (or lack of ) has been reported to contribute to orthodontic instability.6
Arch Length Problems The most common arch length problem in the primary dentition is tooth loss. This is managed as outlined in Chapter 26 with space maintenance if the space is adequate. If space has been lost because of tooth loss, space regaining can be instituted. A notable situation in which to use space regaining is when the primary first molar is lost prematurely. The only realistic space regaining in the primary dentition is repositioning the primary second molar before the permanent first molar erupts. A removable appliance is best used for this purpose. A primary second molar can be repositioned approximately 1 mm per month using a removable appliance with multiple clasps and a finger spring (Fig. 28.1). Three millimeters of molar movement is a realistic extent of the treatment. The appliance is similar to the appliance used to reposition a permanent first molar. If a second primary molar is lost, timely placement of a distal shoe is required, to prevent space loss with the eruption of the permanent first molar. Although inviting and seemingly intuitive, there is little relationship between the arch length (arch perimeter) in the primary and permanent dentitions.7 This means that weak correlations do not support the early interventions advocated by some and described here. Early intervention is expanding the primary arches with either a fixed or a removable appliance. This treatment is provided to ensure space for the permanent teeth.8 The expansion provides variable increases in arch width and arch perimeter and is associated with little long-term benefit.9 This early approach to potential crowding remains controversial and unsubstantiated. It is also important to remember there is a potential to treat up to 4.5 mm of crowding in the late mixed dentition simply with the use of a passive lower lingual arch.10
• Figure 28.1 This appliance was designed to move the right molar distal. Note there are two retentive clasps to hold the appliance in place. The appliance would dislodge as the spring was activated without retention. This type of appliance can move a molar approximately 3 mm.
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Incisor Protrusion and Retrusion In addressing the anteroposterior plane of space, the clinician is mainly concerned with the position of the incisors, particularly the maxillary incisors. The majority of anteroposterior problems involve anterior crossbite, a condition in which the maxillary incisors occlude lingual to the mandibular incisors. A fixed lingual arch or a removable appliance can be used to correct the crossbite, but several things should be kept in mind when moving primary anterior teeth. First, the crowns are extremely short incisogingivally. This means overly aggressive activation of springs will cause them to slip down the lingual surface and not engage the crowns of the teeth. It is best to activate the springs in a facial and gingival direction with gentle activation. Second, the crowns of some primary first molars converge toward the occlusal surface. This makes banding or clasp retention challenging. Third, there are few or no undercuts on the anterior teeth that will engage a labial bow for retention. For this reason, if a labial bow in the primary dentition is not used for tooth movement, it probably should be discarded from the appliance prescription. Finally, because the primary teeth will be exfoliated near 6 to 7 years of age, it is not wise to consider moving a primary incisor much after 4 years of age. Because compliance can be a problem before age 4 years and because primary root resorption and tooth morphology are problems after age 4, few clinicians attempt treatment for anterior crossbites in the primary dentition. If crossbite correction is indicated, a maxillary lingual arch can be designed to push directly on the incisors with reasonably heavy force (0.036-inch wire) or the lingual arch can have lighter forces delivered with attached finger springs (0.022-inch wire). Either way, the arch can be activated to tip maxillary teeth into proper position. The lingual arch is activated approximately 1 mm per visit because it is a heavy-gauge wire that exerts a heavy force. The auxiliary wires can be activated 2 mm (Fig. 28.2). In general, a tooth moves 1 mm per month during treatment. Therefore, if a tooth requires 3 mm of movement to be properly aligned, 3 months of treatment is necessary. With a removable appliance, wire finger springs are incorporated into the palatal acrylic to move the teeth facially. Placing retentive clasps on the posterior teeth stabilizes the appliance. The finger springs are activated 1.5 to 2.0 mm per month. If the patient exhibits a positive overbite and overjet after treatment, retention is probably not necessary because the occlusion generally holds
the tipped incisor in its new position. If there is no overbite, the appliance should be maintained until overbite is established to ensure that relapse does not occur. The decision to correct an anterior crossbite in the primary dentition is a difficult one. The clinician should determine if the crossbite is skeletal or dental in nature. Other factors to consider are the number of teeth involved, the presence of a mandibular shift, and the age of the patient. There are few evidence-based studies to support or refute correction of a dental anterior crossbite in the primary dentition. In other words, would the crossbite self-correct with the exchange of the permanent incisors? Or, does the early correction maintain itself when the permanent incisors erupt? There are hints that self-correction is possible in dental causes of anterior crossbite.11–13 One further point should be made about anterior crossbite. In some cases of posterior crossbite or occlusal interference, a child positions the jaw forward (known as a mandibular shift) to achieve maximal intercuspation and an anterior crossbite results (usually called a pseudo class III malocclusion because the patient is often class I and shifts into a class III position). In this situation the patient positions the lower jaw forward only to obtain comfortable intercuspation as needed to function. This type of anterior crossbite is due to jaw posturing rather than tooth or jaw malposition. In these cases, treatment is directed to the posterior crossbite or the occlusal interference and not to the anterior crossbite. In some cases the interfering tooth is the one in crossbite. Excessive overjet in the primary dentition is usually due to a nonnutritive sucking habit or to a skeletal mismatch between the upper and lower jaws. Most skeletal problems should not be treated at this time because of the tendency for abnormal growth patterns to recur. However, incisor protrusion as a result of a sucking habit can be addressed. Treatment is usually directed at eliminating the habit rather than correcting the incisor protrusion. Incisor protrusion usually corrects itself or is significantly reduced if the habit is discontinued and if the equilibrium between the tongue, lips, and perioral musculature is reestablished. The quad helix, palatal crib, and Bluegrass appliance are discussed in Chapter 27 and are the appliances of choice for habit therapy (see Figs. 27.6 to 27.8). Studies designed to determine how long the appliance must remain in place to terminate the habit effectively suggest a 6-month minimum.14 The key to treatment is whether the patient and the parents both want to have the patient stop the habit. If one or neither is interested in discontinuing the habit, it is best to delay treatment until they are ready.
Posterior Crossbite
• Figure 28.2
This patient’s anterior crossbite involving the primary maxillary central incisors is being treated with a T spring soldered to a lingual arch. The spring is activated 1 to 2 mm per month until the incisors are tipped out of crossbite.
Posterior crossbite in the primary dentition is usually a result of constriction of the maxillary arch. Constriction often results from an active digit or pacifier habit, although there are many cases in which the origin of the crossbite is undetermined. The first step in managing a posterior crossbite is to establish whether there is an associated mandibular shift. If a mandibular shift is present, treatment generally should be implemented to correct the crossbite. Some authors have implicated a mandibular shift as the cause of asymmetric growth of the mandible.15 The asymmetry is thought to occur because the condyles are positioned differently within each fossa. Muscle and soft tissue stretch exert forces on the underlying skeletal and dental structures that may alter normal growth and arch development. If no shift is detected, the mandible should grow symmetrically. It has been suggested to wait on treatment until the permanent molar erupts if there is no mandibular
CHAPTER 28 Orthodontic Treatment in the Primary Dentition
shift.12 After the permanent molar erupts, the clinician can treat if it erupts in crossbite or continue to observe if there is no permanent molar crossbite or mandibular shift. There are two basic approaches to the management of posterior crossbite in young children: (1) equilibration to eliminate mandibular shift and (2) expansion of the constricted maxillary arch. In a few cases the mandibular shift is due to interference caused by the primary canines. These cases can be diagnosed by repositioning the mandible and noting the interference. Selective removal of enamel with a diamond bur in both arches eliminates the interference and the lateral shift into crossbite. This type of treatment has evidenced-based support.16 In cases of bilateral maxillary constriction, expansion is recommended to correct the lateral shift. This situation should be managed as soon as it is diagnosed unless the permanent first molar is expected to erupt within 6 months. If permanent molar eruption is imminent, it is better to allow the permanent molars to erupt and incorporate these teeth into treatment if necessary. Both fixed and removable appliances can be designed to correct maxillary constriction, although fixed appliances are reliable and require little patient cooperation. A randomized prospective study of unilateral crossbite correction in the mixed dentition suggested the most successful intervention was with fixed appliances.17 Fixed appliances are variations of a lingual arch bent into the shape of a W. In fact, one of the most popular appliances used to treat crossbites is named the “W arch” (Fig. 28.3). Another
• Figure 28.3
The W arch is a fixed appliance used to correct posterior crossbites in the primary dentition.
A
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popular appliance is the quad helix (see Fig. 27.6). The W arch is constructed of 0.036-inch wire that rests 1.0 to 1.5 mm off the palate to prevent soft tissue irritation. The W arch is expanded approximately 4 to 6 mm wider than its passive width, or so that one arm of the W is resting over the central grooves of the teeth when the other arm is seated. To move teeth preferentially in the anterior region of the mouth, the appliance is activated by bending the palatal portion of the arm near the solder joint, as demonstrated in Fig. 28.4. If more correction is needed in the molar region, the appliance is activated via bending of the anterior palatal portion. The appliance expands the arch approximately 1 mm per side per month. The patient should return monthly to allow the dentist to check the progress of treatment and to reactivate the W arch if needed. The appliance can be activated intraorally by squeezing the wire with a three-pronged plier, although the force and direction of activation may be difficult to approximate, and unwanted tooth movement can result. Usually it is easier and more accurate to remove, activate, and recement the appliance. Expansion should continue until the crossbite is slightly overcorrected and the lingual cusps of the maxillary teeth occlude on the lingual inclines of the buccal cusps of the mandibular teeth. Most crossbites are corrected in 3 months, and the teeth are retained for an additional 3 months. The quad helix is designed much like the W arch but incorporates more wire into the appliance, making it more flexible. It is constructed of 0.038-inch wire with two helices in the anterior palate and two helices near the solder joint in the posterior palate. The helices are wound away from the palate and can serve to remind the digit-sucking patient to refrain from the habit if they are positioned correctly where the patient places the finger or thumb. Therefore this is the preferred appliance for a patient with a finger habit and posterior crossbite. Because the quad helix has more wire than the W arch, it has a greater range of action and can be activated farther than the W arch while delivering an equivalent amount of force. Overcorrection and retention are also required for the quad helix. Despite activation of the W arch or quad helix on one side only, teeth on both sides of the arch react to equivalent force. These types of fixed lingual arch type appliances have been shown to produce both skeletal and dental changes in the primary and mixed dentitions.17
B • Figure 28.4 (A) The W arch can be activated in two spots. (B) The preferred way to move teeth in the anterior region of the mouth is to activate the W arch by bending the arm of the W in the area marked location 1. Continued
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C
D • Figure 28.4, cont’d
(C) If the clinician wants to obtain more movement in the molar region, the appliance is activated by bending the anterior portion of the W in the area marked location 2. (D) In general, the appliance is activated 3 to 4 mm beyond its passive width or to a position where one arm of the W extends over the central grooves of the teeth when the other arm is seated in place.
Open Bite Vertical problems in the primary dentition usually are due to a finger or pacifier habit, and they result in an anterior open bite. Treatment for an anterior open bite that is due to a sucking habit is discussed in Chapter 27. Deep bite in the primary dentition is generally not corrected at this time. The depth of bite usually improves with the eruption of the permanent first molars if the problem is the result of dental malocclusion.
References 1. Ngan P, Fields HW. Orthodontic diagnosis and treatment planning in the primary dentition. J Dent Child. 1995;62:25–33. 2. Proffit WR, Fields HW, Sarver DM. Treatment of skeletal problems in children. In: Contemporary Orthodontics. 5th ed. St Louis: Mosby; 2012. 3. Kishnan V, Davidovitch Z. Cellular, molecular, and tissue-level reactions to orthodontic force. Am J Orthod. 2005;129:469.e1–469. e32. 4. Redlich M, Shoshan S, Palmon A. Gingival response to orthodontic force. Am J Orthod Dentofacial Orthop. 1999;116:152–157. 5. Lang G, Alfter G, Göz G, et al. Retention and stability—taking various treatment parameters into account. J Orofacial Orthop. 2002;63:26–41. 6. Melrose C, Millett DT. Toward a perspective on orthodontic retention? Am J Orthod Dentofacial Orthop. 1998;113(5):507–514. 7. Bishara SE, Khadivi P, Jakobsen JR. Changes in tooth size–arch length relationships from the deciduous to the permanent dentition:
a longitudinal study. Am J Orthod Dentofacial Orthop. 1995;108: 607–613. 8. McInaney JB, Adams RM, Freeman M. A nonextraction approach to crowded dentitions in young children: early recognition and treatment. J Am Dent Assoc. 1980;101:251–257. 9. Lutz HD, Poulton D. Stability of dental arch expansion in the deciduous dentition. Angle Orthod. 1985;55:299–315. 10. Gianelly AA. Treatment of crowding in the mixed dentition. Am J Orthod Dentofacial Orthop. 2002;121:569–571. 11. Nagahara K, Murata S, Nakamura S, et al. Prediction of the permanent dentition in deciduous anterior crossbite. Angle Orthod. 2001;71(5): 390–395. 12. Dimberg L, Lennartsson B, Arnrup K, et al. Prevalence and change of malocclusions from primary to early permanent dentition: a longitudinal study. Angle Orthod. 2015;85:728–734. 13. Nagahara K, Suzuki T, Nakamura S. Longitudinal changes in the skeletal pattern of deciduous anterior crossbite. Angle Orthod. 1997;67(6):439–446. 14. Haryett RD, Hansen FC, Davidson PO. Chronic thumb-sucking. A second report on treatment and its psychological effects. Am J Orthod. 1970;57:164–178. 15. Primozic J, Richmond S, Kau CH, et al. Three-dimensional evaluation of early crossbite correction: a longitudinal study. Eur J Orthod. 2011;35(1):7–13. 16. Harrison JE, Ashby D. Orthodontic treatment for posterior crossbites. Cochrane Database Syst Rev. 2001;(1):CD000979. 17. Petrén S, Bondemark L. Correction of unilateral posterior crossbite in the mixed dentition: a randomized controlled trial. Am J Orthod Dentofacial Orthop. 2008;133(6):e790–e797.
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Case Study: Orthodontics for the Child With Special Needs John R. Christensen Similar to the general population, children with special needs exhibit varying malocclusions. Many of the malocclusions are found in the general population; however, there seems to be a higher prevalence of severe malocclusion in individuals with physical and mental disabilities. The higher prevalence is explained by abnormal orofacial musculature (abnormal tongue position), craniofacial anomalies, genetics (Down syndrome), and brain injuries (cerebral palsy).1 Each has a malocclusion characteristic of the specific developmental problem. Studies of children with autism spectrum disorder (ASD) have reported mixed findings. One did not find any difference in the Dental Aesthetic Index, a measure of malocclusion severity.2 Another reported children with ASD had an increased prevalence of posterior crossbite, increased overjet, and maxillary crowding.3 Parents inquire about treatment of malocclusion for their child with special needs. Studies have indicated they have a high level of motivation for treatment and are willing to participate in oral hygiene practices.4,5 Parents report the number one reason for orthodontic treatment is to improve facial appearance. Their expectations (and hopes) are that treatment will improve the child’s quality of life, role in society, and his or her social acceptance. The dentist’s role in treating the child with special needs is to discuss orthodontic treatment with the parents and patient. Actually, the clinician should be more of an active listener to determine parent and patient concerns. After discussing the need and motivation for treatment, the clinician should consider whether treatment seems reasonable, is achievable, and promises some stability. Each child needs to be evaluated on an individual basis. Some will be good candidates. Other patients could benefit from orthodontics, but because of the disability, care will be difficult and may not be stable.6
Behavior Every child has some innate ability to cooperate with treatment. The dentist must consider how much ability is within the child to cooperate. Oftentimes, behavior can be guided to examine the teeth only, whereas other times the patient may allow complete dental care. Several questions should be considered. Can the child physically sit for appliance placement? Will the child allow appliances to be placed? Will the appliance cause gagging or difficulty eating? Can the child clean the appliances so the teeth are not put at risk during treatment? Oftentimes these questions can be answered prior to the start of treatment, but there are times when the limits of cooperation are not known. In general, the clinician can determine a patient’s ability to cooperate during the records appointment. The clinician can assess whether a patient will follow directions or is cooperative for procedures such as radiographs and photographs. Does the child gag? Can the gag reflex be managed? Even something as simple as moving the dental chair can startle a child with special needs. Staff need to be trained and encouraged to deliver care in multiple ways. For example, the chair may not be completely reclined, the dental light may not be used, or the patient may need to sit up to drink water from a cup rather than being rinsed with an air/water syringe and suction. The clinician should note patient behaviors as the records are obtained. If records are difficult or impossible to obtain, orthodontic treatment may be just as difficult. Appointment scheduling should be adapted to the individual child. Often a series of desensitization appointments are necessary to acclimate the child to the orthodontic world. Different chairs, different staff, and different doctors are just some of the challenges for a child with special needs. It is helpful to schedule care in the same chair with the same staff so the child has some ability to anchor his or her care from appointment to appointment. The time for each appointment should be adjusted to accommodate the child. The typical time for an orthodontic procedure may be twice as long for the patient with special needs.
Patient’s Ability to Tolerate the Appliance After records, the clinician presents a problem list and treatment plan to the family. The dentist should determine from the records appointment or from discussion with the parent whether the patient can tolerate orthodontic appliances. Often it is prudent to place limited orthodontic appliances on the teeth (in a passive state) to determine if the patient can tolerate the appliances. After it is established the child can tolerate the appliances, additional appliances can be added. For example, in a case requiring upper and lower arch treatment, the clinician may place brackets on the upper front teeth. This is an area that is easy to access for placement and removal if necessary. If the child does well with this treatment, additional brackets can be placed on the lower arch or the upper posterior teeth. Appliance placement is staged so the clinician can terminate treatment without creating a situation in which work must continue to get the teeth into a stable position. The most obvious example of staged treatment is tooth removal. It is wise to start appliances prior to tooth removal even if there is no room to move teeth until extractions have been performed. After it is apparent the patient will tolerate appliances, the teeth can be removed. If teeth are removed first and the patient is not a good candidate for treatment, the patient can end up with an even worse situation. If a removable appliance is being considered, one can construct a sham appliance or deliver the actual appliance without activation. Children can be overwhelmed by a removable appliance, so it is important to introduce it slowly. The patient can be asked to wear the appliance on day 1 for one-half hour. Each day another increment of wear can be added until the targeted time is achieved. If the appliance is intended for night wear, it can be helpful to start the appliance during waking hours. The patient can develop confidence in the appliance before attempting to sleep with it at night.
Patient’s Ability to Cooperate With the Treatment Plan Cooperation in treatment is as important in a child with special needs as it is in a normal child. The clinician should be prepared to modify the plan or the intended treatment based on the individual’s ability to cooperate. This can mean extended chair time to allow the child time to feel comfortable and receive care. It can mean proposed treatment for the day will be postponed due to the child’s inability to cooperate or receive treatment on that particular day. Staff must be trained to deliver care in a manner different than normal. For example, tooth-brushing instructions will vary if a child has a physical difference that prevents a normal brushing stroke. A different technique, a different toothbrush, or another individual must be used to provide good home care. A child with a sensory disorder may not be able to tolerate the taste of materials used to prepare teeth. It may be necessary to use a different material. The key is flexibility for the clinician and staff. The rule is there are no rules to treatment approach.
Stability of Results As with children without disabilities, the clinician needs to consider several variables in the retention plan. The orthodontic literature is full of questions about retention and the stability of tooth movement. In a patient with special needs, the clinician should consider several issues. Will the patient be able to tolerate an appliance? Will the patient wear the appliance? Is a fixed retainer a better option for retention? Will oral hygiene be more difficult with a fixed retainer? Will a patient (with a sensory disorder) tolerate the taste or texture of a retainer? In cases of patients with muscular issues (cerebral palsy), retention appropriate for a normal child may not work due to the difference in muscle activity or may not be tolerated due to swallowing and drooling difficulties. There are an unlimited number of issues to consider in retention, and it is nearly impossible to anticipate every one. The clinician must be well versed in orthodontic retention and the literature. Each patient requires an individual retention plan based on the special need of the patient. Continued
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Questions 1. What barriers to orthodontic care do children with special needs face? Answer: The child with special needs faces several barriers to care. The first is finding a dentist who is trained and comfortable with treating children with different needs. The second is similar to the first, and that is finding a dentist who participates in Medicaid and other programs designed to help these children. Reimbursement rates are lower in these programs, and many dentists choose not to participate due to the rates. Children with special needs have mental and physical disabilities that may interfere with the delivery of orthodontic care. 2. Describe ways a dentist can measure if a child with special needs will tolerate orthodontic care? Answer: The first answer to this question is how the child does with general dental care. If the patient is cooperative and maintains good oral health, the child will typically do well for orthodontic care. If the child requires extra guidance during regular care, the clinician should anticipate more guidance will be needed for orthodontic care. A stepwise progression is often appropriate to determine the child’s tolerance for care. Orthodontic appliances can be introduced slowly and placed without activation (teeth will not move) just to determine how the child will do with orthodontic appliances. If the child is doing well, the appliance can be activated to move teeth or more appliances can be added. If the child is not doing well with orthodontic care, the limited appliances can be removed without harm to the patient. 3. List five ways orthodontic care may be different for a child with special needs. Answer: • Appointment lengths may be longer to accommodate the child’s special needs.
• Treatment plans may be less comprehensive and more flexible due to several unknown factors relating to each child’s special needs. • Treatment is staged so if a child cannot tolerate treatment, discontinuing treatment will not result in leaving the patient in a worse condition than the start. • Materials may need to be varied depending on the sensitivities of the patient. This may be a result of multiple allergies or just a sensitivity disorder to a certain taste or texture. • The clinician and staff may vary from the scheduled treatment for the day depending on the disposition of the patient and the ability of the patient to tolerate treatment that day. There is a much greater range of behaviors to negotiate in the child with special needs.
References 1. Rada R, Bakhsh HH, Evans C. Orthodontic care for the behavior-challenged special needs patient. Spec Care Dentist. 2015;35(3):138–142. 2. Luppanapornlarp S, Leelataweewud P, Putongkam P, et al. Periodontal status and orthodontic treatment need of autistic children. World J Orthod. 2010;11(3):256–261. 3. Fontaine-Sylvestre C, Roy A, Rizkallah J, et al. Prevalence of malocclusion in Canadian children with autism spectrum disorder. Am J Orthod Dentofacial Orthop. 2017;152(1):38–41. 4. Abeleira MT, Pazos E, Ramos I, et al. Orthodontic treatment for disabled children: a survey of parents’ attitudes and overall satisfaction. BMC Oral Health. 2014;14(1):98. 5. Becker A, Shapira J, Chaushu S. Orthodontic treatment for the special needs child. Prog Orthod. 2009;10(1):34–47. 6. Becker A, Shapira J, Chaushu S. Orthodontic treatment for disabled children: motivation, expectation, and satisfaction. Eur J Orthod. 2000;22(2):151–158.