Biomechanical and Clinical Considerations in correcting Skeletal Class II Malocclusion with ForsusTM

Abstract

Aim The present case report describes the importance of understanding of biomechanical and clinical considerations in application of Forsus appliance in correction of class II skeletal malocclusion. Background Angle's class II malocclusion is one of the most prevailing that may be either skeletal or dental presenting with different clinical manifestations. There are number of appliances to treat such a malocclusion in a growing child. Fixed functional appliances are indicated for class II corrections in patients who report late with minimal residual growth left. Case description A case of class II skeletal and dental malocclusion treated with preadjusted edgewise appliance supplemented with Forsus Fatigue Resistant Device (FRD) (3M Unitek Corp, California, USA) is reported. Conclusion Forsus device is an effective alternative in treating moderate skeletal class II malocclusion. The Forsus FRD (3M Unitek Corp, California, USA) can be used instead of class II elastics in mild cases and in place of Herbst appliance in severe cases. Alteration of force vector by modifying the archwire as shown in this case report while applying Forsus and incorporation of 10 degree labial root torque in lower archwire will minimize the effects on dentition. Engaging modules or tubing on to the pushrod and leaving 1 to 2 mm clearance between distal end of the upper tube and L-pin as shown in this case report will significantly improve the patient compliance. Clinical significance Much emphasis should be given to biomechanical considerations which were discussed in this article while treating patients with Forsus to prevent the unwanted effects. Clinical considerations and certain modifications advised in this case report should be utilized while treating class II skeletal malocclusions with Forsus appliance to eliminate the patient cooperation factor and make treatment time estimates much more accurate. How to cite this article Adusumilli SP, Sudhakar P, Mummidi B, Varma DPK, Arora S, Radhika A, Maheshwari A. Biomechanical and Clinical Considerations in correcting Skeletal Class II Malocclusion with ForsusTM. J Contemp Dent Pract 2012; 13(6):918-924.

Optimization of Class II Malocclusion Treatments Using the Forsus™ Fatigue Resistance Device and Its Post-Treatment Effect in Adult Patients: A Case Report

“…It is a comfortable device [7], as it does not completely limit the mandible movement and, in the current version, it shows a very low breakage rate [10,14,[32][33][34]. The Forsus appliance, when installed in the upper first molar tube in the lower leveling arch wire, at the distal of the cuspid bracket [3,11,15,17] or, at the distal of the lower first premolar [14], exerts a force of 220 g approximately in both jaws, in opposite directions [15,35]. And, the time it takes to completely correct a Class II malocclusion may vary from 5 -8 months on average [6,14,15,17].…”

“…Such considerations occurred due to the lack of studies comparing the control group, presenting the same malocclusion, to the treated group [5,6], the lack of patient's cooperation [7][8][9], the use of removable orthopedic devices in growing patients [8], the high breakage rate of fixed orthopedic appliances [10][11][12][13], and, discomfort caused to patients by the use of removable and fixed orthopedic devices [10,11,13]. In the twenty-first century, the launch of the Forsus™ Fatigue Resistant Device brought a new proposal to treatments, considering patient comfort in the set-up day and along the treatment, due to the lack of mandibular postural change and easiness of performing the functional mandibular movements [7,11,[14][15][16][17]. Additionally, there are also scientific evidences demonstrating that the impact on growth pattern is temporary after treatment as, in a long-term run, changes responding to growth pattern already exists genetically [3,16,[18][19][20][21][22][23][24][25].…”

“…The mandible may undergo anterior shift, improving the maxillomandibular relationship [1,3,5,6,11,13,15]. However, the effective growth of the mandible will rarely be considered an effect genuinely generated by the stimulus of the mandibular anterior growth [1,5,10,15,35,36], although there are authors that report some potential for effective growth in the mandibular body and ramus, when functional fixed devices are used in the pubertal growth peak stage [1,3,6,9,13].In the literature, it has been shown that dentoalveolar changes overcome the skeletal changes when any fixed functional device is used [4][5][6]21]. The mechanism of the dentoalveolar action of such devices over the upper anterior [2,[5][6][7][8][9][10][11]14,15,17,28,36,37] and posterior teeth [3,6,[8][9][10][11]13,35,36] and over the lower anterior …”

“…However, the effective growth of the mandible will rarely be considered an effect genuinely generated by the stimulus of the mandibular anterior growth [1,5,10,15,35,36], although there are authors that report some potential for effective growth in the mandibular body and ramus, when functional fixed devices are used in the pubertal growth peak stage [1,3,6,9,13].…”

“…The mechanism of the dentoalveolar action of such devices over the upper anterior [2,[5][6][7][8][9][10][11]14,15,17,28,36,37] and posterior teeth [3,6,[8][9][10][11]13,35,36] and over the lower anterior [5,6,8,[9][10][11][13][14][15]17,28,[35][36][37] and posterior teeth [3,8,[9][10][11]14,17] are often responsible for the clockwise shift of the occlusal [5,9,10,16,17,35] and palatal [2] planes, generating a clockwise resultant on the mandibular plane …”