Point of Care the “Point of Care” Section Answers Everyday Clinical Questions by Providing Practical Information That Aims to Be Useful at the Point of Patient Care

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Point of Care The “Point of Care” section answers everyday clinical questions by providing practical information that aims to be useful at the point of patient care. The responses reflect the opinions of the contributors and do not purport to set forth standards of care or clinical practice guidelines. Readers are encouraged to do more reading on the topics covered. If you would like to contribute to this section, contact editor-in-chief Dr. John O’Keefe at [email protected].

Q u e s t i o n 1 Do missing teeth need to be replaced or is a “shortened dental arch” acceptable?

Background noticed a change in chewing function when they 2 or many years, it was thought that any missing had fewer than 6 units (Figs. 1 and 2). tooth should be replaced,1 although num- The Effect of a Shortened Dental Arch on Ferous clinicians and researchers questioned Oral Function this opinion. Arnd Käyser was the first to coin the term “shortened dental arch” (SDA) to de- In general, studies comparing people with a full complement of teeth with those with SDAs scribe the concept of acceptable oral function with have not demonstrated significant differences in partial dentition.2 Through a number of clinical ability to chew.1 Among patients with the min- studies, he and his co-workers came to the conclu- imum recommended number of occlusal units, the sion that many people could function without a insertion of a removable partial denture does not full complement of teeth and that not all missing 3 2–6 significantly improve oral function. According to teeth require replacement. For many people, a some studies, the more teeth missing beyond the functional dentition consists of as little as op- minimum, the more difficulty a person will have 1 posing anterior and premolar teeth. In terms of chewing.1 a minimum number of teeth that patients need, In addition, those without molar support have Käyser and colleagues suggested that, in addition not been shown to have a higher incidence of the to anterior teeth, most people require at least 4 oc- signs and symptoms of temporomandibular disor- clusal units of posterior teeth (1 pair of opposing, ders.5 Similarly, SDA has not been associated with occluding premolars would be 1 occlusal unit, a significant discomfort, distress or occlusal wear.1 pair of occluding molars would represent 2 oc- Although it seems that most people can func- clusal units).2 People with asymmetrical tooth loss tion acceptably with an SDA, this is not true

Figure 2: Here molar 16 and premolars 44 and 45 are unopposed; thus, they cannot be counted as occlusal units. Although overeruption of teeth, as seen here, can be a sequela to missing teeth, long-term Figure 1: Patients with symmetrical tooth loss (left) normally studies have tended to show that occlusal require 4 occlusal units for acceptable function, while patients changes are usually self-limiting and minor.1 with asymmetrical tooth loss normally require 6 occlusal units (right). Darkened teeth are missing.

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Figure 3: This patient has 4 premolars left. Figure 4: A prosthesis for replacement of Figure 5: A maxillary complete If they are opposed by maxillary teeth, only a few missing teeth may be unneces- denture against mandibular anterior there are no other complicating factors and sary if the patient has no functional or teeth does not meet the minimum the patient has no functional or esthetic esthetic complaints and there are no other number (4) of occlusal units required complaints, then replacement of the missing reasons for replacement. for normal function. A mandibular teeth may not be necessary. prosthesis may be helpful for such patients.

for everyone: 7% to 20% of people with an SDA may be no need to replace missing teeth, unless have reported that their chewing ability is hin- they are unhappy with their ability to chew or dered or that they had to change food preparation their appearance (Figs. 3 and 4). For patients with practices.1 4 or more occlusal units who do not feel they can An SDA may also be associated with greater chew as well as they wish, replacements can still be tooth migration and interdental spacing among fabricated (Fig. 5). patients younger than 40 years, although the mi- The SDA concept is based on the notion that gration was deemed small and clinically insignifi- patients have an adaptive capacity to function with cant.1 An SDA may also be associated with greater missing teeth. This capacity clearly varies, and not overeruption of teeth, although only 2% of such all patients will feel they have optimum function patients reported that it hindered their oral func- with the same number of teeth. Future research tion.1 People with SDA have been found to have will most likely improve our understanding of this more mobile teeth and lower alveolar bone levels. clinically relevant subject. a The combination of increased occlusal loading and existing periodontal disease probably repre- THE AUTHOR sents a risk factor for further loss of teeth in these people. Patients with SDA probably also represent a high-risk group in terms of periodontal disease. Dr. Robert Loney is professor and head, division Additional longitudinal studies have been recom- of removable prosthodontics, faculty of dentistry, 1 Dalhousie University, Halifax, Nova Scotia. ��Email: mended to study this relationship. [email protected].

Shortened Dental Arch Options in Dental References Practice 1. Kanno T, Carlsson GE. ��A review of the shortened dental arch The SDA concept is increasingly accepted, al- concept focusing on the work by the Kayser/Nijmegen group. J Oral Rehabil 2006; 33(11):850–62. though in some areas, it is not widely put into 2. Kayser AF. Shortened dental arches and oral function. J Oral 1 practice. For dentists who provide services to pa- Rehabil 1981; 8(5):457–62. tients with limited financial resources or patients 3. Witter DJ, van Elteren P, Kayser AF, van Rossum MJ. The effect of removable partial dentures on the oral function in shortened dental who do not wish to acquire a prosthesis, the evi- arches. J Oral Rehabil 1989; 16(1):27–33. dence provides a measure of reassurance that “no 4. Witter DJ, de Haan AF, Kayser AF, van Rossum GM. A 6-year treatment” can be a sound option. Considering the follow-up study of oral function in shortened dental arches. Part I: implications of informed consent and the evidence Occlusal stability. J Oral Rehabil 1994; 21(2):113–25. 5. Witter DJ, De Haan AF, Kayser AF, Van Rossum GM. A 6- collected by Käyser and others, it is prudent to year follow-up study of oral function in shortened dental arches. ensure that treatment planning for all partially Part II: Craniomandibular dysfunction and oral comfort. J Oral edentulous patients includes a discussion of the Rehabil 1994; 21(4):353–66. 6. Witter DJ, van Palenstein Helderman WH, Creugers NH, Kayser option of not replacing missing teeth and the pros AF. The shortened dental arch concept and its implications for oral and cons of this choice. For many patients, there health care. Community Dent Oral Epidemiol 1999; 27(4):249–58.

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Q u e s t i o n 2 A patient new to my practice had a heart transplant a few years ago. What are the chief considerations in the management of this patient?

Background prudent to monitor blood pressure throughout the ince the pioneering surgery of Dr. Christian dental appointment. Furthermore, stress manage- Barnard and his team in the 1960s, human ment measures, such as oral sedation, inhalation Sheart transplantation has evolved into a sur- or sedation, may be indicated. The lack of sensory gical procedure with a reasonably predictable out- innervation of the transplanted heart also implies come. Many heart transplant recipients now have that, in the event of angina or myocardial infarc- a greatly increased life expectancy and are able to tion, the patient would not experience the retro- sternal pain associated with both emergencies.2 return to normal daily life. Although medically The transplanted heart is nevertheless acutely compromised, they are typically more stable from sensitive to circulating catecholamines and is con- a cardiovascular perspective than patients with sequently affected by epinephrine-containing solu- a history of severe cardiac disease.1 With special tions.3 Among transplant recipients surviving for care, routine dental or minor oral surgical proced- 5 years or longer, about 40% will have accelerated ures may be undertaken within the dental practice graft atherosclerosis. The cardiac complications setting. However, for more invasive procedures, that may arise include myocardial infarction, con- referral may be appropriate. There is no general gestive heart failure, ventricular arrhythmias and systematic approach to dental treatment for these sudden death.2 It is good clinical practice to limit patients, making close liaison with the primary the amount of epinephrine necessary to maintain care physician and cardiologist essential. local anesthesia among these patients to 0.04 mg A medical letter sent to the cardiologist and for dental procedures.4 physician will help to confirm the patient’s medical The 2007 American Heart Association guide- history and current medications. The letter should lines on antibiotic prophylaxis to prevent infective include proposed dental surgical treatment, along endocarditis do not advise blanket coverage for with the concentration and dose of drugs that will cardiac transplant patients.5 Unless a patient de- be used (e.g., local anesthetics, antibiotics and an- velops cardiac valvulopathy, is immunosuppressed algesics). The response to this correspondence will or has been directed by the cardiology team to have report the medical status and stability of the trans- antibiotic coverage, prophylaxis is unnecessary. plant and the fitness of the patient to undergo dental procedures in an office setting. The Effects of Immunosuppressant Therapy Management in the Dental Office Heart transplant recipients generally take 3 The transplanted heart is unable to respond to types of immunosuppressant drugs to prevent re- stress because of the lack of innervation; thus, it is jection. Each class of drug has a distinct effect on

Table 1 Types of immunosuppressants

Effect on dental Class of drug Example Side effects treatment Precautionary measures Antimetabolites Azathioprine Leukopenia, Increase risk of Order blood work before Rapamycin thrombocytopenia bleeding and infection invasive dental procedures (INR, CBC, ptt) Steroids Prednisone Possible adrenal Impaired response to stress Consult with physician to suppression determine whether steroid supplementation is required Antiproliferatives Cyclosporine Adverse effects on Hypertension Monitor blood pressure, Tacrolimus kidney notify physician if elevated

INR = international normalized ratio; CBC = complete blood count; ptt = partial thromboplastin time.

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Figure 1: Cyclosporine-induced gingival Figure 2: Gingival hyperplasia in a hyperplasia. pediatric patient.

the immune system as well as important side ef- THE AUTHORS fects that may affect dental treatment (Table 1).4,6 Acknowledgements: We would like to thank Dr. Ian Matthew Cyclosporine induces gingival hyperplasia. The for his help with the preparation of the manuscript and Dr. Tom predisposing factors are multifactorial and hyper- Daley for providing the photographs. plastic cases range from mild to severe (Fig. 1). Dr. Krista D. Lee recently completed a residency The severity has been linked to oral hygiene status. in the General Practice Residency Program at the University of British Columbia,�� Vancouver General Transplant patients benefit from a 3–4 month re- Hospital, Vancouver, British Columbia. Email: call program of professional oral hygiene mainten- [email protected]. ance and education reinforcing the importance of Dr. Anthony�� Antoniazz��i� recently completed a personal oral hygiene measures. Not all patients residency in the Advanced Education in General develop gingival hyperplasia, but those affected Dentistry Program, Temple University Kornberg acquire clinical manifestations within 6 months School of Dentistry, Philadelphia, Pennsylvania. post-transplant.7 Following 36 months post-trans- The authors have no declared financial interests. plant, many affected patients show a gradual improvement in tissue overgrowth due to progressive References 1. Montebugnoli L, Prati C. Circulatory dynamics during dental reduction in the sensitivity of the periodontium extractions in normal, cardiac and transplant patients. J Am Dent to cyclosporine. Therefore, surgical intervention Assoc 2002; 133(4):468–72. 2. Little JW, Rhodus NL. Dental management of the heart transplant to manage gingival hyperplasia is delayed until patient. Gen Dent 1992; 40(2):126–31. 36 months has passed.7 3. Meechan JG, Parry G, Rattray DT, Thomason JM. Effects of dental local anaesthetics in cardiac transplant recipients. Br Dent 2002; 192(3):161–3. Pediatric Considerations 4. Haas DA. An update on local anesthetics in dentistry. J Can Dent Assoc 2002; 68(9):546–51. Many of the treatment concerns described 5. Wilson W, Taubert KA, Gewitz M, Lockhart PB, Baddour LM, above apply to the pediatric transplant patient; Levison M, and others. Prevention of infective endocarditis: guidelines from the American Heart Association: a guideline from the however, some problems are specific to the pedi- American Heart Association Rheumatic Fever, Endocarditis and Kawasaki Disease Committee, Council on Cardiovascular Disease atric patient. Children appear to be more suscept- in the Young, and the Council on Clinical Cardiology, Council on ible to gingival hyperplasia than adults because of Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group. J Am Dent less attention to oral hygiene and a shorter period Assoc 2007; 138(6):739–60. of administration of immunosupressants.8 In chil- 6. Little JW, Falace DA, Miller CS, Rhodus NL. Dental management of the medically compromised patient. St. Louis: Mosby Inc.; 2002. dren, hyperplastic tissue caps may develop over p. 271–82. erupting teeth, which can delay, prevent or modify 7. Montebugnoli L, Servidio D, Bernardi F. The role of time in re- ducing gingival overgrowth in heart-transplanted patients following eruption patterns9 (Fig. 2). Surgical intervention cyclosporine therapy. J Clin Periodontol 2000; 27(8):611–4. 8. Khocht A, Schneider LC. Periodontal management of gin- is sometimes required; thus, regular monitoring gival overgrowth in the heart transplant patient: a case report. of pediatric patients allows better treatment plan- J Periodontol 1997; 68:1140–6. 9. Ansari F, Ferring V, Schulz-Weidner N, Wetzel WE. Concomitant ning to assist the natural eruption of the perma- oral findings in children after cardiac transplant. Pediatr Transplant nent dentition. a 2006; 10(2):215–9.

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Q u e s t i o n 3 What is the best technique for obturating the root canal system?

Background effective and user friendly. It involves fitting a he steps in successful root canal treatment in- standard size master cone corresponding to the clude access and identification of all canal ori- master apical file size. It requires a continuously Tfices; instrumentation to the canal terminus; flared canal with an apical stop or tapering control irrigation to disinfect and dissolve pulpal tissue; zone. For optimal deformation of material, the obturation; and, finally, placement of an orifice spreader must be prefitted so that it extends deeply seal and definitive restoration to prevent micro- into the empty canal without binding. Nickel ti- leakage and tooth fracture. Inadequate treatment tanium hand spreaders may penetrate more deeply, at any of these steps will likely result in the per- generate less internal stress and distribute forces sistence, occurrence or recurrence of apical peri- more evenly than others.3 Accessory cones must odontitis (Fig. 1a and 1b). be sequentially added to eliminate voids and mini- Three of the most commonly used techniques mize sealer thickness. The major limitation of CLC for obturation are cold lateral condensation (CLC), is the inability to move the obturation material warm vertical condensation (WVC) and warm car- or sealer into irregularities of the main canal or rier-based obturation (WCBO). All 3 are used to branches. seal in (entomb) any potential irritants that could WVC has been described as obturating in 3-D, not be removed with instrumentation and irriga- indicating an intention to fill all ramifications of tion; to remove space for regrowth of bacteria; the pulp space including accessory canals. It is the and to eliminate leakage, including from the peri- experience of most endodontists that the ability to radicular tissue into the root canal system. fill canal irregularities and branches has been best Although certain methods may appear concep- demonstrated with this technique. For WVC to be tually better and in vitro leakage studies have effective, the canal must be properly cleaned and shown differences, no single approach has shown shaped to provide the hydraulics necessary to force unequivocal evidence of superior healing in out- the softened material and sealer into these irregu- come studies.1,2 Choice of an obturation method larities, while providing the resistance needed to may be based on such factors as speed, simplicity, prevent overfilling. This is accomplished by prep- economics or practitioners’ impressions from ex- aration that continually tapers to an apical control perience and individual and serial case reports. zone with the canal patent to the terminus. For obturation, a medium or fine-medium cone is cut Management of the Issue to fit snugly in the apical control zone. Fit must be CLC is the obturation technique most com- precise to prevent migration of the cone with apical monly taught in dental school, as it is safe, cost pressure, and the canal must have been shaped

Figure 1a: Poor fill is an indication of Figure 1b: Retreatment involved finding a Figure 2: This tooth remained symptomatic insufficient cleaning and disinfection. fourth canal and cleaning and disinfecting following treatment. Poor apical control to the canal terminus to set up the condi- and the use of excess sealer with carrier- tions for healing. based obturators resulted in extrusion of excess material beyond the apex.

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express the sealer into a c canal irregularities and ensure minimal film thickness. With a carrier-based technique, it b is extremely important to use a very light coating of sealer on Q u e s t i o n 1 the walls, as placement Question of the warmed carrier will have a piston effect, with potential expres- sion of excess sealer into the periradicular Figure 3: (a) Two small-diameter, carrier-based obturators were used in an attempt to seal this large tissues.3 canal. Insufficient fill resulted. (b) Retreatment involved removal of the carriers. (c) The canal was then cleaned, disinfected and obturated with mineral trioxide aggregate in the apical half followed by Conclusion application of a core material to seal. Shortfalls in obturation are most often a sufficiently to allow the heat source to penetrate result of inadequate canal preparation. Indeed, (ideally, 5 mm from cone length).4 The cone is contemporary research points to cleaning and dis- compacted and excess material removed, leaving infection of the root canal as the single most im- an apical plug. Backfilling with obturation ma- portant step in preventing and treating endodontic terial against this plug completes the procedure. disease.6 From a clinical standpoint, each practi- WCBO attempts to provide the advantages of tioner should employ an obturation technique that a warm technique in a simplified, fast, controlled provides consistent, predictable results that meet a manner. Following instrumentation and disinfec- high standard. When the practitioner is in doubt tion, a verifier file is used to check length; the as to whether a high standard can be achieved, he carrier, surrounded with warm gutta-percha, is or she should seek help from an endodontist who then placed to this length. This technique has been is trained, equipped and experienced in treating a embraced by many general dentists because it is these cases. fast, and apical control is achieved by pushing the carrier to length. Radiographically, the fill will THE AUTHOR appear dense due to the radiopacity of the carrier, and additional anatomy may be captured. Dr. Mike Rampado maintains an endodontic Disadvantages include the inability to obtain specialty practice in Kelowna, British Columbia. a film verifying cone fit, stripping of the gutta- Email: [email protected]. percha away from the carrier and possible expres- sion of material beyond the apex (Fig. 2).5 In cases of persistent or recurrent disease, the plastic car- References rier can sometimes be difficult and frustrating to 1. Wu MK, Wesselink PR. Endodontic leakage studies reconsidered. Part I. Methodology, application and relevance. Int�� Endod J 1993; remove, particularly when instrumentation was 26(1):37–43. insufficient (Figs. 3a–3c). For these reasons WCBO 2. Kirkevang LL, Horsted-Bindslev P. Technical aspects of treatment has not been widely embraced by endodontists. in relation to treatment outcome. Endod Topics 2002; 2:89–102. 3. Whitworth J. Methods of filling root canals: principles and prac- Sealer is always necessary to fill the space be- tices. Endod Topics 2005; 12:2–24. tween the obturation material and canal wall ir- 4. Wu MK, van der Sluis LW, Wesselink PR. A preliminary study of regularities, fins and branches. It should cover the the percentage of gutta-percha-filled area in the apical canal filled with vertically compacted warm gutta-percha. Int Endod J 2002; entire wall and be of minimal thickness. Sealer is 35(6):527–35. also required to fill the spaces between the master 5. Clinton K, Van Himel T. Comparison of a warm gutta-percha and accessory cones in lateral condensation. When obturation technique and lateral condensation. J Endod 2001; WVC is used, the cone can be liberally coated 27(11):692–95. 6. Haapasalo M, Endal U, Zandi H, Coil JM. Eradication of endo- with sealer because excess can flow out coronally dontic infection by instrumentation and irrigation solutions. Endod during cone placement. Downpack hydraulics then Topics 2005; 10:77–102.

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Q u e s t i o n 4 How should I treat a young patient in the primary or early mixed dentition stage who presents with unilateral posterior crossbite and mandibular shift?

Background Evaluating the axial inclination of the pos- osterior crossbite of the primary or mixed terior teeth in study models can be used to deter- dentition can be caused by a skeletal or a mine whether the crossbite is dental or skeletal. Pdental discrepancy. Skeletal crossbite is due If this evaluation shows that the crossbite could to deficiency of the transverse maxillary arch, be corrected by removing the transverse dental a wider-than-normal mandibular arch or both. compensation, the discrepancy is probably dental Dental crossbite can occur when the arches are of in nature. If the crossbite appears worse after the adequate width but the maxillary teeth are tipped compensations are removed, it is probably skeletal lingually and/or the mandibular teeth are tipped in origin. buccally. The incidence of posterior crossbite in Intraoral examination may reveal a functional shift of the mandible into maximum intercuspa- the primary, mixed and permanent dentitions tion. This may be due to dental interferences (usu- ranges between 7% and 23%.1 ally of the primary canines) but is often a result A crossbite affecting only one tooth is often of bilateral maxillary constriction. However, se- dental in nature and can occur as a result of vere constriction may result in bilateral crossbite crowding. For example, early loss of a maxillary without a functional shift. To diagnose a func- primary second molar may cause lingual displace- tional mandibular shift, the patient can be asked to ment of the second premolar.2 Dental crossbite roll the tongue to the posterior palate, which helps in the primary dentition is uncommon, because to bring the mandible into a retrusive position. crowding is rare. A crossbite affecting one tooth can With gentle guidance the clinician can move the also occur when a retained primary tooth disrupts mandible into retrusion and will see the first point the eruption path of its permanent successor. of contact and then the slide. A posterior crossbite may be unilateral or bilateral. True unilateral crossbite results from intra- Timing of Treatment arch or skeletal asymmetry, which may have a Crossbite with functional shift is one of the few pathologic cause, such as unilateral cleft lip and conditions requiring treatment in the primary den- palate or unilateral condylar hyperplasia. Bilateral tition.3 If the permanent first molars are expected crossbite may have the same underlying causes as to erupt in less than 6 months, treatment can be unilateral crossbite, but there is more maxillary delayed so that these teeth can be included in the constriction distributed throughout the arch and correction. The proportion of posterior crossbites no forced shift of the mandible. Although most that persist into the permanent dentition is signifi- crossbites of the primary or early mixed denti- cant but variable (8% to 45%).4,5 If not corrected, a tion are unilateral in appearance as a result of a functional shift may lead to undesirable adaptation mandibular shift to one side on closure, they are of the temporomandibular joint, asymmetric man- actually bilateral crossbites. dibular growth, dental compensations and dental abrasion. Treatment in the early mixed dentition Diagnosis stage also leads to improvement in mandibular Frontal examination may demonstrate lateral asymmetry.6 deviation of the chin toward the side of the func- Delaying treatment until the late mixed or tional shift. Mandibular asymmetry may occur as a permanent dentition stage has been advocated,3,4 result of asymmetric growth due to the functional to allow possible spontaneous correction, to avoid shift. If such asymmetry is present, posteroanterior multiple phases of treatment and to allow the pa- or submental radiography may help to assess its tient to reach a developmental stage with better presence and extent. Lateral cephalometric radi- cooperation and self-motivation. However, such ography (at maximum intercuspation and at the a delay risks development or worsening of man- point of initial contact, before the functional shift dibular asymmetric growth. occurs) may be helpful but can be technically chal- Crossbite should not be corrected in the lenging if the patient is very young. presence of a sucking habit, as the crossbite will

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Figure 1: Fixed quad helix in a patient with Figure 2: A 7-year-old girl presented with Figure 3: A removable maxillary maxillary deficiency. Compliance is not an unilateral posterior crossbite on the left side, expansion appliance was delivered, issue with this appliance, which can be along with a 3-mm functional shift to the with instructions for full-time wear and activated intraorally if further expansion is left and a midline discrepancy. turning 2 times per week. required. The arms can be removed and the appliance can act as a cost-effective fixed retainer.

Figure 4: At 12 weeks, 6 mm of expan- Figure 5: The appliance was worn as a Figure 6: Six months after initial sion had been achieved, and the unilateral retainer. presentation, the functional shift and posterior crossbite and functional shift had crossbite remained absent and the been corrected. midlines were coincident. The patient was compliant with use of the removable appliance.

a minor functional shift (less than 1 mm); expansion of the maxillary arch; or repositioning of individual teeth, combined with use of crossbite elastics, to deal with intra-arch asymmetries, in cases of localized dental crossbite. Application of light transverse expansive forces at the midpalatal suture can result in skeletal and Figure 7: A fixed transpalatal arch was then dental changes to correct the crossbite or trans- cemented with bands on the first permanent molars, with arms extending to the lin- verse deficiency. Heavy forces from a rapid palatal gual surface of the primary first and second expander in the primary or early mixed dentition molars for retention. may cause distortion of the nose and should therefore be delayed until the patient is in the middle to late mixed dentition stage. probably return after treatment unless the habit In a patient with unilateral crossbite as a result is eliminated. However, appliance therapy may of a functional mandibular shift, bilateral trans- simultaneously discourage the sucking habit and verse expansion is generally necessary. Removable correct the crossbite. maxillary expanders are advantageous, as they re- There are 3 approaches to treating moderate quire little chair time and can include a bite plate to posterior crossbite in children3: occlusal equili- assist in the disarticulation of the posterior teeth. bration to eliminate interferences, in cases with Fixed appliances such as the quad helix (Fig. 1)

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or W-arch are also useful and do not depend on Dr. William A. Wiltshire is professor and head of the patient compliance. They act quickly, have minimal department of orthodontics, division of preventive effects on speech and generally deliver a continuous dental science, University of Manitoba, Winnipeg, light force. After the expansion has been achieved, Manitoba. the active component of the quad helix can be removed and the buccal arms left in place to provide References 1. Kennedy DB, Osepchook M. Unilateral posterior crossbite with a cost-effective means of retention. mandibular shift: a review. J Can Dent Assoc 2005; 71(8):569–73. For true unilateral crossbite, a removable ap- 2. Ninou S, Stephens C. The early treatment of posterior cross- pliance is preferred, with an asymmetrically bites: a review of continuing controversies. Dent Update 1994; 21(10):420–6. placed expansion screw toward the side of the 3. Proffit WR. Contemporary orthodontics. 3rd ed. St. Louis (MO): crossbite and more acrylic palatal coverage toward Mosby Co., 2000. p. 187–8, 435–9. the normal side. This permits more basal bone 4. Malandris M, Mahoney EK. Aetiology, diagnosis and treatment of posterior cross-bites in the primary dentition. Int J Paediatr Dent anchorage on the normal side and more expan- 2004; 14(3):155–66. sion on the side with the crossbite. The case pre- 5. Marshall SD, Southard KA, Southard TE. Early transverse treat- sented here illustrates the successful treatment of ment. Semin Orthod 2005; 11(3):130. 6. Hesse KL, Artun J, Joondeph DR, Kennedy DB. Changes�� in con- a unilateral crossbite with a removable maxillary dylar position and occlusion associated with maxillary expansion for expansion appliance. Once successful expansion correction of functional unilateral posterior crossbite. Am J Orthod was achieved (Figs. 2–4), the patient continued to Dentofacial Orthop 1997; 111(4):410–8. wear the appliance as a retainer (Figs. 5 and 6). Six months after initial presentation (3 months after Further Reading completed expansion), a fixed transpalatal arch Bartzela T, Jonas I. Long-term stability of unilateral posterior crossbite correction. Angle Orthod 2007; 77(2):237–43. was cemented in place (Fig. 7). The patient’s facial Harrison JE, Ashby D. Orthodontic treatment for posterior cross- musculature was balanced, and the buccal seg- bites. Cochrane Database Syst Rev 2006; 2:CD 000879. ments had effective interdigitation, which should Petren S, Bondemark L, Soderfeldt B. A systematic review con- cerning early orthodontic treatment of unilateral posterior cross- assist in establishing long-term retention. She will bite. Angle Orthod 2003; 73(5):588–96. be monitored every 3 to 6 months. Pinto AS, Buschang PH, Throckmorton G, Chen P. Morphological and positional assymetries in young children with functional unilateral posterior crossbite. Am J Orthod Dentofacial Orthop 2001; Conclusion 120(5):513–20. Treatment of posterior crossbite in the pri- Schiffman PH, Tuncay OC. Maxillary expansion: a meta analysis. mary or early mixed dentition is indicated when a Clin Orthod Res 2001; 4(2):86–96. Turpin DL. Dealing with posterior crossbite in young patients. functional mandibular shift is present. Otherwise, Am J Orthod Dentofacial Orthop 2004;126(5):531–2. there is a risk of long-term asymmetric mandibular growth. Treatment usually takes the form of an expansion appliance in the maxilla; retention protocols should be considered once successful expansion has been achieved and the crossbite has been eliminated. a

THE AUTHORS

Dr. James Noble is a senior orthodontic resident in the faculty of dentistry, University of Manitoba, Winnipeg, Manitoba. Email: umnoble@ cc.umanitoba.ca.

Dr. Robert C. Baker is senior scholar, department of orthodontics, University of Manitoba, Winnipeg, Manitoba.

Dr. Nicholas Karaiskos is a senior orthodontic resident in the faculty of dentistry, University of Manitoba, Winnipeg, Manitoba.

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