רפואת הפה והשיניים - עיתון ההסתדרות לרפואת שיניים בישראל - כרך ל"ז, גיליון מס' 2 אייר תש"פ

and by overall encouragement of both patients and parents to religiously use the appliance. As transverse expansion also affects the facial sutural systems (2), the question has arisen regarding the necessity to expand the maxilla during facemask protraction, while there is no transverse discrepancy but no consensus has been reached yet (2, 18). 3. Chin cup (Fig 5) A chin cup should only be used in SkCl3 cases of mandibular origin, as it is not effective for SkCl3 patients with maxillary etiology. Chin-cups are extra oral orthopedic restraining appliances that target the mandibular joint. Due to an oblique upward inclination, most of the forces are directed at the condyle, resulting in growth restraint (2). Skeletal changes typically result in an increase in the anterior facial height (31) and rotation of the chin downward and backward which can camouflage the SkCl3 anomaly. Unfortunately, dental changes such as lingual tipping of the lower incisors are often unavoidable. A major potential setback might commence, if mandibular growth catches up after early treatment. This may lead to elimination of any achieved improvement and may cause recurrence of the prognathic mandible and Class III malocclusion. In these patients, the general dental practitioner can play a decisive role in treatment success by simple means, ranging from hygiene, early detection and treatment of caries and bruxism and overall encouragement to wear the appliance until full completion of facial growth around adulthood. 4. Skeletal anchorage: (Fig 6) Recently introduced by De Clerck (32), skeletal anchorage by mini implants inserted directly to the bone opens new possibilities to better treat SkCl3. The use of more favorably-situated anchor points delivers more predictable results, especially with patients treated after the age of 10 (32, 33). Skeletal anchorage for Class III correction offers two advantages; it minimizes dento-alveolar changes with the benefit of increasing skeletal changes, and it minimizes the downward and backward mandibular rotation. The application of skeletal anchorage

can be either through miniplates embedded in the zygomatic bone combined with facemask protraction, or by using miniplates in the lower jaw. In both cases, forces should be applied at least 16 hours per day (32, 33). There are reports of good results with more than 5 mm anterior maxillary movement per year, when miniplates are used (32, 33). In addition to the advantages of delivering greater magnitudes of forces to the maxilla, this approach fosters improved compliance, force application nearly full-time and very good esthetic results.(32, 33) Note however, that the disadvantages of the two surgical procedures required for application and removal of the miniplates cannot be ignored. A conservative alternative for skeletal anchorage is known as Temporary Anchorage Devices (TADs), which are implants that do not require any major surgical procedures. Nonetheless, these devices are not considered as early treatment because they have an age limit where usually they can be applied only after the age of 12 (32). In patients treated with implants, the general dental practitioner may need to coordinate maintenance, gingival hygiene and routine oral care with strict prevention of any bruxism or incipient caries. Conclusion Treatment of SkCl3 is very challenging, primarily due to the unpredictable and potentially unfavorable nature of facial growth in these patients. However, a variety of treatment modalities enhanced by more compact designs (32, 33) increase treatment options and flexibility. In many cases, conservative orthodontic treatment, supported by an engaged general dental practitioner, may be sufficient to avoid orthognathic surgery or at least reduce the severity of future surgical correction, needed after completion of growth. All SkCl3 patients must be monitored until cessation of growth by both the orthodontist and the treating general dental practitioner. The complexity and intrusiveness of the appliances used and the extended duration of treatment require very good rapport with the patient and his parents. Patients and their parents must understand the complexity of the treatment and the significance of cooperation

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The Journal of the Israel Dental Association, vol. 37, No. 2, April 2020.