|Year : 2018 | Volume
| Issue : 3 | Page : 167-173
Cephalometric evaluation of dentoskeletal and soft-tissue changes with powerscope Class II corrector
Aditi Malhotra1, Kehar Singh Negi2, Jai Ram Kaundal3, Nishant Negi4, Monika Mahajan4, Dimple Chainta4
1 Junior Resident, Department of Orthodontics and Dentofacial Orthopedics, Himachal Pradesh Government Dental College and Hospital, Shimla, Himachal Pradesh, India
2 Prof. and Head, Department of Orthodontics and Dentofacial Orthopedics, Himachal Pradesh Government Dental College and Hospital, Shimla, Himachal Pradesh, India
3 Prof, Department of Orthodontics and Dentofacial Orthopedics, Himachal Pradesh Government Dental College and Hospital, Shimla, Himachal Pradesh, India
4 Lecturer, Department of Orthodontics and Dentofacial Orthopedics, Himachal Pradesh Government Dental College and Hospital, Shimla, Himachal Pradesh, India
|Date of Submission||06-Jun-2017|
|Date of Acceptance||14-Mar-2018|
|Date of Web Publication||18-Jul-2018|
Dr. Aditi Malhotra
Room No. 307, Department of Orthodontics and Dentofacial Orthopedics, Himachal Pradesh Government Dental College and Hospital, Shimla, Himachal Pradesh
Source of Support: None, Conflict of Interest: None
Objectives: The objective of the study is to assess the skeletal, dental, and soft-tissue effects of PowerScope fixed functional appliance in Class II malocclusion. Materials and Methods: Fifteen late adolescent Class II subjects (CVMI Stages 5 and 6) were treated with fixed mechanotherapy and PowerScope fixed functional appliance. Student t-test was used to compare the cephalometric changes produced before insertion of appliance (T1) and 6 months after the treatment with this appliance (T2). Results: Maxillomandibular relationship improved with significant lengthening of the mandible. There was retroclination of maxillary incisors, proclination of mandibular incisors, extrusion, and sagittal displacement of mandibular molars and clockwise rotation of occlusal plane. Conclusion: PowerScope is effective in correcting Class II malocclusion with a combination of dentoalveolar (primarily) and skeletal changes.
Keywords: Class II, fixed functional, PowerScope
|How to cite this article:|
Malhotra A, Negi KS, Kaundal JR, Negi N, Mahajan M, Chainta D. Cephalometric evaluation of dentoskeletal and soft-tissue changes with powerscope Class II corrector. J Indian Orthod Soc 2018;52:167-73
|How to cite this URL:|
Malhotra A, Negi KS, Kaundal JR, Negi N, Mahajan M, Chainta D. Cephalometric evaluation of dentoskeletal and soft-tissue changes with powerscope Class II corrector. J Indian Orthod Soc [serial online] 2018 [cited 2018 Oct 21];52:167-73. Available from: http://www.jios.in/text.asp?2018/52/3/167/237093
| Introduction|| |
Class II malocclusion is the most frequent sagittal problem in orthodontics. There are many different dental and skeletal combinations that can create a Class II malocclusion. According to McNamara, the most common characteristic of Class II malocclusion is mandibular retrognathism. In such malocclusions, functional appliances are commonly used to encourage mandibular growth in a favorable direction. A variety of different removable and fixed functional appliances have been used for correction of Class II malocclusion. Removable appliances such as bionator, activator, Twin block, and Frankel functional regulator produce variable results due to their dependence on patient compliance and frequently requiring a second phase of fixed mechanotherapy. On the other hand, fixed functional appliances such as Herbst appliance, Jasper Jumper, and Forsus Fatigue-resistant device are not dependent on patient cooperation as they can be attached directly to fixed appliance assembly. They are of minimal inconvenience to the patient since all oral functions are still possible. Other advantage is that Class II malocclusion can be corrected in a single phase.
Many studies have found these appliance to be effective in correction of Class II malocclusion by a combination of maxillary restraint, mandibular lengthening, dentoalveolar changes, and glenoid fossa remodeling.,
PowerScope Class II corrector is a newer fixed functional appliance introduced by American Orthodontic Corporation in 2014. It is a one-piece spring loaded chair side appliance with a telescopic mechanism that can directly be attached to the main archwire. Its insertion is less time consuming, and it is more economical as compared to its counterparts. No study has yet been documented in the literature which describes the effect of this appliance except for a few case reports., The aim of this study was to evaluate the effects produced by PowerScope appliance in skeletal Class II malocclusion using lateral cephalograms.
| Materials and Methods|| |
The study sample consisted of 15 postpubertal (CVMI Stages 5 and 6) individuals having average growth pattern with following inclusion criteria:
- Skeletal Class II pattern; ANB >4°
- Overjet >5 mm
- Full cusp Class II or end on molar relationship
- Presence of all permanent teeth up to the first molar
- Well-aligned dental arches having minimal crowding/spacing.
- Positive VTO
- No previous history of orthodontic treatment.
The exclusion criteria included:
- Previous history of orthodontic treatment
- Congenitally missing or extracted permanent teeth
- Medically compromised patients
- Negative VTO.
Ethical Approval was obtained from the Ethical Committee of the institution (IRB No. HFW-B(B) 15-10/2013). A nonextraction treatment plan was decided for all these patients. All patients were treated with MBT 0.022” prescription. All the teeth were leveled and aligned up to 0.019 × 0.025” stainless steel archwire. Thereafter, PowerScope was attached to the archwire distal to mandibular canine and mesial to maxillary first molars on both sides [Figure 1]a, [Figure 1]b, [Figure 1]c. To prevent the proclination of mandibular incisors, 6° negatively torqued mandibular incisor brackets were used, and archwires were cinched distal to mandibular molars. Regular follow-up at 1-month interval was done. PowerScope was kept in place for an average time period of 6 months. Lateral cephalograms were taken before the placement of PowerScope (T1) and after its removal (T2) at 6 months interval. Each radiograph was taken with teeth in maximum intercuspation, lips relaxed, and subjects oriented in natural head position. These cephalograms were analyzed for dentoskeletal and soft-tissue changes from T1 to T2 using various cephalometric parameters [Figure 2] and [Figure 3]. [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8] represent one of the 15 patients treatment progresses.
|Figure 1: PowerScope appliance. (a) right lateral (b) frontal (c) left lateral|
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|Figure 6: Intraoral photographs and radiographs 1 month before debonding|
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Statistical analysis was done using IBM corporation, IBM SPSS Statistics for Windows, Version 22.0. (Armonk, NY: IBM Corp). Standard descriptive statistics (mean, standard deviation, and standard error of mean) were calculated for present sample. Paired t-test was used to assess the difference in the parameters from T1 to T2 stage. To determine the error of method, the same investigator retraced and remeasured 10 randomly selected cephalograms. Correlation analysis revealed no significant error of method. The power of study at 95% confidence interval was more than 80%.
| Results|| |
Significant differences were found for various dentoskeletal and soft-tissue parameters from T1 to T2. These results are summarized in [Table 1] and [Table 2] and graphically represented in [Graph 1] and [Graph 2]. No significant change in maxillary skeletal parameters was observed after treatment as determined by the values SNA, Co-A, and Point A-Nperp. There was a statistically significant increase in SNB angle by 1.067°. Mandibular length (Co-A) increased significantly by 1.6 mm. Significant improvement in sagittal relationship was observed by change in the ANB value which decreased by 0.867° (P = 0.013). There was no significant change in the growth pattern of the patients as dictated by mandibular plane angle value. Maxillary incisors were retroclined as well as retropositioned by 6.33° and 2.06 mm, respectively. Mandibular incisors were forwardly placed and proclined with respect to NB line by 2.13 mm and 7°, respectively. IMPA increased by 6.87°. Overjet and overbite reduced by 5.8 mm and 1.73 mm, respectively. These changes were very highly significant (P = 0.001) with marked improvement in molars relation with changed to Class I postfunctionally. Among the soft-tissue measurements, H angle and lip strain reduced significantly by 1.09° and 1.8 mm whereas, U lip/E-line increased significantly by 1.05 mm.
| Discussion|| |
This study evaluated the skeletal, dental, and soft-tissue changes in late adolescent patients treated with the PowerScope fixed functional appliance. The use of fixed functional orthopedic appliances in patients at postpeak stage of growth has been reported in the literature. Treatment at this stage offers better occlusal stability as all permanent teeth have erupted allowing better intercuspation in Class I relationship. As the Class II correction is done closer to completion of active craniofacial growth, relapse tendency due to reestablishment of Class II growth characteristics is expected to occur less often.,
Similar to findings of Aras and Ada, no significant restraining effect was observed on maxilla. This is in contrast with the findings of Pancherz. Distension of the musculature that holds the mandible in constantly advanced position causes transmission of the action of this muscular force in posterior direction on the maxilla, thus promoting restriction of maxillary growth. Insignificant effect on maxilla could be explained by the fact that the subjects in this study were in late adolescents and most of the growth of maxilla is completed by this time.
Clinically significant improvement in anteroposterior spatial position of mandible was found which also helped to reduce the facial convexity. Mandibular length increased by about 1.6 mm during the 6-month appliance wear. In the absence of a matched control, it is very difficult to predict the contribution of normal growth to this improvement. However, due to ethical concerns, no control group was used in this study. However, rigid fixed functional appliances have been reported to improve the maxillomandibular relationship as compared to flexible functional appliances.,,
There was a statistically insignificant decrease in mandibular plane angle. This appliance may be used in high-angle subjects having average to low smile line without any side effects such as downward and backward rotation of mandible which is usually seen after treatment with removable functional appliances.
A significant uprighting effect was seen on maxillary incisors. This headgear like effect was a favorable outcome as incisors were more labially tipped before treatment. Although functional appliances exert a distal and intrusive force on maxillary molars yet clinically significant distalization and intrusion were not seen in our study. As reported with other functional appliances, there was a marked proclination of mandibular incisors., This side effect was observed despite the use of negatively torqued brackets and cinching of archwire distal to mandibular molars. This might have been due to telescopic mechanism of PowerScope which exerts a mesially directed force on mandibular anteriors. Additional lingual torquing of archwires in mandibular anterior region may reduce the tendency of lower incisors to flare out. This unfavorable outcome of fixed functional appliances cannot be totally prevented as the point of force application in mandibular anterior region is above the center of resistance of dentoalveolar unit. Anchorage reinforcement by micro implants is being increasingly used with fixed functional appliances to limit this proclination.,
Significant extrusion of mandibular first molars along with retrusion of maxillary incisors and protrusion of mandibular incisors resulted in clockwise rotation of occlusal plane. Interincisal angle decreased by 0.66° from T1 to T2. There was a net reduction in overjet due to combination of proclination in mandibular arch and retroclination in maxillary arch. Some of this reduction was also due to forward posturing of the mandible. Overbite also reduced significantly due to combined effect of downward and backward rotation of occlusal plane and proclination of mandibular incisors. Molar relationship showed significant improvement from Class II to Class I relationship. This was primarily due to mesialization of lower dentoalveolar segment. These dentoalveolar changes are in accordance with the findings reported in the literature.,
As has been reported with other appliances, there was a marked improvement in soft-tissue profile in this study as well., Retroclination of maxillary incisors resulted in backward movement of upper lips thereby reducing the lip strain significantly. The lower lip was no longer captured behind the upper incisors, and proclined lower incisors supported the lower lips.
Thus the results show that this appliance can successfully correct Class II malocclusion in postpubertal subjects. However, further studies will be needed to evaluate the long-term effects and stability of the results obtained with this appliance.
| Conclusion|| |
- PowerScope is an effective appliance for Class II correction
- Class II correction was achieved through a combination of skeletal and dental changes
- There was lengthening of the mandible (1.6 mm) with no restraining effect on maxilla
- Maxillary incisors retroclined, mandibular incisors proclined, and mandibular molars moved forward and upward
- Occlusal plane rotated in clockwise direction.
The reduction in overjet and correction of molar relation postfunctionally was due to proclination of lower incisors, mesial movement of lower molars and retroclination of upper incisors which showed statistically highly significant values compared to increase in mandibular length of about 1.6 mm which was just significant. Hence, it was concluded that although there were significant skeletal changes dentoalveolar change contributed mostly to correction of Class II relation.
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]
[Table 1], [Table 2]