|Year : 2019 | Volume
| Issue : 1 | Page : 62-68
Treatment of skeletal class II malocclusion using miniplate anchorage with fixed functional appliance
Suresh Gorantla1, Madhurima Thokala2, Darsana Maru2, Prabhakar Veginadu3, Sudha Sravani Konathala2
1 Prof. and HOD, Department of Orthodontics, Sree Sai Dental College and Research Institute, Srikakulam, Andhra Pradesh, India
2 PG Student, Department of Orthodontics, Sree Sai Dental College and Research Institute, Srikakulam, Andhra Pradesh, India
3 Senior Lecturer, Department of Orthodontics, Sree Sai Dental College and Research Institute, Srikakulam, Andhra Pradesh, India
|Date of Submission||25-Jul-2018|
|Date of Acceptance||25-Sep-2018|
|Date of Web Publication||04-Feb-2019|
Dr. Suresh Gorantla
Department of Orthodontics, Sree Sai Dental College and Research Institute, Srikakulam - 532 001, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
The aim of the present case report was to present the treatment of a growing patient with skeletal class II malocclusion with by mandibular retrusion using PowerscopeTM anchored to mini plates. After initial leveling and alignment of the upper arch using fixed appliance (MBT prescription; 0.022-inch slot), 0.021 X 0.025-inch SS arch wire was inserted. One week after the placement of miniplates bilaterally at the symphysis of mandible, powerscope was installed on to the miniplates and the upper 0.021 X 0.025 inch archwire anterior to the molars. After eight months, powerscope was removed and lower arch strap up was done. Favorable skeletal and dental changes were observed at the end of active treatment with powerscope and finishing and detailing with fixed appliance.
Keywords: Fixed functional appliance, mandibular retrusion, miniplates, powerscope, skeletal anchorage system
|How to cite this article:|
Gorantla S, Thokala M, Maru D, Veginadu P, Konathala SS. Treatment of skeletal class II malocclusion using miniplate anchorage with fixed functional appliance. J Indian Orthod Soc 2019;53:62-8
|How to cite this URL:|
Gorantla S, Thokala M, Maru D, Veginadu P, Konathala SS. Treatment of skeletal class II malocclusion using miniplate anchorage with fixed functional appliance. J Indian Orthod Soc [serial online] 2019 [cited 2019 Feb 21];53:62-8. Available from: http://www.jios.in/text.asp?2019/53/1/62/251553
| Introduction|| |
Class II malocclusion, with a prevalence of approximately one-third of the population, continues to be a major and common challenge to orthodontists.,, It could be a dental Class II with or without an unseen skeletal component. Skeletal Class II jaw relation could be due to a prognathic maxilla, retrognathic mandible, or a combination of both. According to McNamara, the most common characteristic of Class II malocclusion is mandibular retrusion rather than maxillary prognathism.
There are several types of removable and fixed functional appliances for the correction of Class II Division 1 malocclusion with mandibular deficiency to stimulate mandibular growth by forward positioning of the mandible. The selection of appliance varies according to the patient's growth pattern, type of anomaly, and clinician's priorities.,
Removable appliances, such as activator, bionator, Twin block, Frankel regulator, are ideally indicated in patients who have not crossed the adolescent growth spurt. If the patient reports after pubertal growth spurt or during late stages of puberty, fixed functional appliances would be a better choice to use because of patient compliance and can be used concurrently with fixed appliance.
Some of the fixed functional appliances commonly used are fixed twin block, Herbst appliance, jasper jumper, eureka spring, universal bite corrector, forsus resistant device, and power scope. Dr. Andy Hayes worked in conjunction with American Orthodontics to develop Powerscope which serves critical needs of the orthodontist with simple installation, extensive range of motion, patient comfort, and acceptance. It allows for simultaneous skeletal correction along with fixed appliance.
Several studies describe the efficiency with which the fixed functional appliances work. However, distal and intrusive movement of maxillary molars, mesial movement of mandibular molars, retrusion of maxillary incisors, and protrusion of mandibular incisors have been reported to be some disadvantages of conventional fixed functional appliances.,,,,
Aslan et al. and Manni et al. reported the use of miniscrews as indirect anchorage to prevent the undesirable dental sequelae of fixed functional appliance.,
Celikoglu et al. have reported the use of miniplates on the mandible for engaging forsus fatigue-resistant device directly on to the mandible and observed favorable skeletal and dental changes.
The use of miniplates on the mandible for engaging powerscope has not been reported earlier. This case report demonstrates the use of modified miniplate with powerscope for the correction of a skeletal Class II malocclusion.
| Diagnosis And Etiology|| |
A boy, aged 13 years, was referred to the Department of Orthodontics and Dentofacial Orthopaedics, Sree Sai Dental college and Research Institute, Srikakulam. His chief complaint was crowding and forwardly placed the upper front teeth. The pretreatment clinical examination revealed that he has a thumb-sucking habit since childhood, symmetric face, convex profile, and lip trap.
On examination, Class II Division 1 malocclusion with Class II canines, an increased overjet (7 mm) and overbite (4 mm), and crowding in maxillary and mandibular anterior teeth region were observed. The mandibular and maxillary dental midline almost coincided with the facial midline. No temporomandibular disorder signs or symptoms were observed [Figure 1].
The panoramic radiographic findings showed that all third molars were impacted. The maxillary central and lateral incisor on the left side had Ellis Class1 fracture. Examination of the left hand and wrist radiograph suggested 10%–25% of adolescent growth was expected [Figure 2].
Cephalometric analysis showed that he has a skeletal Class II malocclusion (ANB, 11°; Wits appraisal, 8 mm) with mandibular retrognathism relative to the frontal cranial base (SNA: 82°; SNB: 71°). The patient has a vertical skeletal growth pattern (SN-GoGn: 43°). The maxillary and the mandibular incisors were proclined (U1-SN: 105°, UI-NA: 23°, IMPA: 100°, L1-NB: 9 mm), and the interincisal angle was 110° [Table 1].
|Table 1: Cephalometric values of facial skeleton, dental, and soft-tissue parameters - pre-, mid-, post-treatments|
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The clinical visual treatment objective of the patient was positive [Figure 3].
Treatment objectives were to correct the mandibular retrusion using symphysis bone anchored miniplates with fixed functional appliance (Powerscope), to relieve crowding in the maxillary arch and mandibular arch, to eliminate increased overjet and overbite, and to achieve Class I canine and molar relationships with a functional occlusion.
Brackets with MBT prescription (0.022” slot) were bonded to the maxillary teeth and bands were placed with a transpalatal arch to minimize side effects on the posterior segment. Leveling and alignment of the upper arch were done with multilooped 0.016” SS AJ Wilcock special plus archwire to relieve crowding followed by higher archwires. Leveling and alignment were completed in 6 months, and after the first phase of the treatment, the overjet and overbite measurements were 7 mm and 2 mm, respectively [Figure 4].
|Figure 4: Intraoral photographs of the patient during leveling and alignment|
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Three-holed titanium miniplates (L-shaped) were placed bilaterally at the symphysis of the mandible under local anesthesia. The miniplates were adjusted so that they fit to the contour of the symphysis. They were fixed by three bone screws made of titanium, and the other end of the miniplate was placed distal to canine on each side and at a little distance from the gingival margin to maintain good oral hygiene. The rationale behind using L-shaped mini plate was to gain more stable fixation [Figure 5].
One week after the insertion, powerscope was installed on to the miniplates and to the upper 0.021” × 0.025” archwire, anterior to the first molars. The patient was recalled at 4-week intervals, and the activation was done by adding 2-mm crimps onto the pushrod. Eight months after the skeletal anchored powerscope worn, Class I canine and molar relations were achieved, and overjet was eliminated [Figure 6]. After skeletally anchored powerscope was surgically removed, finishing and settling of occlusion were continued with fixed appliance. After achieving ideal occlusion and intercuspation, the appliance was debonded [Figure 7].
|Figure 6: Extraoral and intraoral photographs post-skeletal anchored powerscope|
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| Results|| |
Pretreatment values suggest Class II skeletal pattern (ANB: 11°) with orthognathic maxilla (SNA: 82°) and retrognathic mandible (SNB: 71°) and vertical growth pattern (SN-Go-Gn: 43°, FMA: 33°), with slighty proclined upper incisors (U1-NA: 25°; U1-NA: 2 mm) and lower incisors (L1-NB: 36°; L1-NB: 9 mm; IMPA: 100°) and overjet and overbite of 7 mm and 2 mm, respectively. The mandible was anteriorly positioned as indicated by an articular angle (S-Ar-Go: 131°) with reduced body length (Co-Gn: 97 mm).
The cephalometric values at the end of the treatment show a 4° reduction in the ANB angle (7°). This was achieved by a change in the positions of maxilla and mandible (SNA: 81° and SNB: 74°) and increase in the length of the mandible (CO. GN: 102 mm, Composite mandibular length (pg/OLp + co/OLp): 84 mm). The angular and the linear positions of the upper and lower incisors were relatively similar to the pretreatment values (U1-NA: 25°; U1-NA: 2 mm, is/OLp minus A point/OLp: 11 mm). There was a decrease in the overjet by 4 mm (is/OLP minus ii/OLP-4 mm) [Figure 8], [Figure 9] and [Table 1], [Table 2]. There was a marked improvement in the soft-tissue profile with reduction of facial convexity and competent lips.
| Discussion|| |
Class II malocclusion, among all the malocclusions, presents a constant challenge to the orthodontists. Class II malocclusions due to mandibular retrusion in growing patients are most commonly corrected with functional appliances, which initiate remodeling changes at the mandibular condyle and glenoid fossa to facilitate repositioning the condyle in the glenoid fossa.
As the patient described in this case report was in late mixed-dentition period with about 10%–25% of growth still remaining, one phase approach was considered to be favorable, to minimize the treatment time, and to harness the remaining growth. Hence, a fixed orthodontic mechanotherapy along with fixed functional appliance was planned.
Several methods, including the use of sectional mechanics, reverse torque brackets, miniscrews, and skeletal anchorage system, have been described in the literature to prevent the lower incisor protrusion caused by fixed functional appliance therapy.,,, Aslan et al. have reported that among these methods, miniscrew system was found to be more effective in eliminating lower incisor proclination. However, they have observed that miniscrew system in conjunction with fixed functional appliance brings about only dentoalveolar changes.
In a recent case report, Celikoglu et al. described the use of miniplates as direct anchorage for Forsus FRD appliance and reported significant skeletal changes in the patient following treatment. In our case report, we have demonstrated the use of powerscope in conjunction with miniplates. Commonly available versatile L-shaped surgical titanium plates were adapted to be used in the patient [Figure 5].
Powerscope is a fixed one-piece appliance, available in a single size suiting all Class II patients. It consists of a telescopic mechanism of Herbst appliance and incorporates the advantage of the flexibility of the hybrid appliance. The ball and socket joint at the two ends of the appliance allow excellent jaw movements reducing a great degree of patient discomfort. Our case report is the first to use a powerscope in conjunction with miniplates. The powerscope was attached to one of the holes of the miniplate with the help of screws supplied with the appliance, an easier and clinician-friendly method of engagement [Figure 6].
The cephalometric skeletal values after the removal of powerscope show restrained maxillary growth (SNA: −1°; Co-Pt. A: −1 mm; ΔOLp-Pt. A: −1 mm) and increased mandibular body length (SNB: +3°; Co-Gn: +5 mm; ΔOLp-Pt. B: +4 mm). The growth had primarily occurred in the condyle region, along with some growth in the chin, which was confirmed by modified Pancherz superimposition [Figure 10]. This resulted in a decrease in the ANB angle by 4° (ANB: 7°). In accordance with the previous studies, which used skeletal anchorage for fixed functional appliances, there was retroclination of upper and lower incisors (U1-NA: 23°; U1-NA: 2 mm and L1-NB: 32°; L1-NB: 7 mm) [Table 1] observed immediately after the appliance removal.,,,,, According to the authors, this was attribute to the headgear effect of fixed functional appliance and pressure of upper incisors and lower lip, respectively. In this patient, cessation of the thumb-sucking habit of the patient could have further contributed to this effect.
|Figure 10: Modified Pancherz Superimposition tracings pre- and post-treatments (pre-treatment: Blackline and post-treatment red)|
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Cephalometric analysis after debonding shows the skeletal changes obtained with powerscope were maintained through the end of the treatment. However, the retroclined upper and lower incisors reverted to the pretreatment values (U1-NA: 25°; U1-NA: 2 mm and L1-NB: 35°; L1-NB: 9 mm) [Table 1].
The purpose of using miniplate-anchored powerscope was to avoid taking anchorage from the lower dentition and in turn eliminating the lower incisor proclination. This was confirmed by the cephalometric superimposition using modified Pancherz analysis which showed negligible change in the lower incisor position and inclination, pre- and post-treatment (ii/OLp minus pg/OLp: 0 mm) [Table 2] and [Figure 10]. However, the occlusal plane had steepened (SN-OP: 24°) [Table 1] due to the intrusion of molars. There was also the distal movement of the maxillary molars, possibly due to the headgear effect of the appliance (ΔOLp-Um: −5 mm) [Table 2].
Overall, comparing the cephalometric outcomes, a considerable improvement in skeletal, dental, and soft-tissue parameters was observed after skeletally anchored powerscope treatment. The posttreatment cephalometric measurements revealed favorable sagittal skeletal changes; significant advancement of the mandible along with inhibition of maxillary growth [Figure 10]. Despite the requirement of a minor surgical procedure for miniplate insertion, the greater skeletal correction achieved with the use of skeletal anchorage counterweighs the limitations.
| Conclusion|| |
The combination of skeletal anchorage system with powerscope helped in favorable growth modification and achieving Class I canine and molar relations without causing significant proclination of mandibular anteriors. Further studies, with a considerable sample size, might provide a better insight of the various changes brought about by this protocol.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10]
[Table 1], [Table 2]