Journal of Indian Society of Pedodontics and Preventive Dentistry
Journal of Indian Society of Pedodontics and Preventive Dentistry
                                                   Official journal of the Indian Society of Pedodontics and Preventive Dentistry                           
Year : 2010  |  Volume : 28  |  Issue : 1  |  Page : 30--33

Treatment effects produced by preorthodontic trainer appliance in patients with class II division I malocclusion


UM Das, D Reddy 
 Department of Pedodontics and Preventive Dentistry, V. S. Dental College and Hospital, Bangalore, Karnataka, India

Correspondence Address:
U M Das
Department of Pedodontics and Preventive Dentistry, V. S. Dental College and Hospital, Bangalore, Karnataka
India

Abstract

The aim of the present study was to evaluate cephalometrically the treatment effects of preorthodontic trainer on dentoskeletal components in individuals showing class II division I malocclusion. This study comprised of 50 class II div. I patients (20 test patients and 30 controls) in the age group of 8-12 years. The test group was treated with a preorthodontic trainer for a period of 15 months. Standardized lateral cephalograms of both groups were taken before and after the treatment period. The cephalograms were then evaluated to determine the skeletal and dental changes in the course of treatment and then compared with the normative growth data to eliminate the possible growth effects. The readings were tabulated and subjected to statistical analysis. The results of the study after excluding the changes due to growth showed reduction in ANB and OP-SN values, indicating a significant reduction in the skeletal class II relationship. An upward cant of the occlusal plane in the treatment group was noted, probably due to the forward rotation of mandible. A significant increase in the vertical dimensions of the face in general and the mandible in particular was observed with the use of preorthodontic trainer. A significant reduction in the overjet and an increase in the inclination of mandibular incisor (L1-NB deg) were noted in the treatment group when compared with control group. It can be concluded that class II corrections can be achieved with the preorthodontic trainer appliance, which appears to have mostly dentoalveolar effects with smaller but significant skeletal effects.



How to cite this article:
Das U M, Reddy D. Treatment effects produced by preorthodontic trainer appliance in patients with class II division I malocclusion.J Indian Soc Pedod Prev Dent 2010;28:30-33


How to cite this URL:
Das U M, Reddy D. Treatment effects produced by preorthodontic trainer appliance in patients with class II division I malocclusion. J Indian Soc Pedod Prev Dent [serial online] 2010 [cited 2021 Dec 8 ];28:30-33
Available from: https://www.jisppd.com/text.asp?2010/28/1/30/60480


Full Text

 Introduction



The class II division I malocclusion has been said to be the most frequent treatment problem in orthodontic practice. [1] Although maxillary protrusion and mandibular retrusion are both found to be possible causative factors, it has been reported that the most common component in a class II sample population is mandibular retrusion. [2] The ideal means of correction is to target the source and try to alter the amount or direction of growth in that jaw. The primary treatment for this purpose is functional appliance therapy. [3] The term functional appliance refers to a variety of removable or fixed appliances designed to alter the mandibular position both sagittally and vertically, resulting in orthodontic and orthopedic changes. [4] Several types of functional appliances are currently in use for class II treatment aimed at improving existing skeletal imbalances, arch form and orofacial function. [5] These functional appliances demonstrate a significant diversity in design, which could affect their acceptance by patients. Although Bionator or Twin blocks are more acceptable compared with Activators, patients do not easily adapt to these appliances because of their large size and unfixed position in the mouth. An ideal functional appliance should be comfortable to the patient, allow jaw movements, leave room for tongue and provide skeletal rather than dental effects. [6]

The aim of the present study was to evaluate cephalometrically the treatment effects of preorthodontic trainer on dentoskeletal components in class II division I malocclusion and to compare the skeletal and dental changes brought about by the preorthodontic trainer appliance with those in a control group.

 Materials and Methods



The study included 50 children in the age group of 8-12 years visiting the Department of Pedodontics and Preventive Dentistry, V. S. Dental College and Hospital, Bangalore, with class II division I malocclusion. Patients with overjet greater than 10 mm, reluctant child or parent, patients with history of any previous orthodontic treatment and patients with severe nasal obstruction were not included in the study.

Treatment group included subjects who were instructed to wear the preorthodontic trainer everyday for 1 hour and overnight while they sleep, and the control group included subjects who refused to undergo any treatment.

At the start of treatment, lateral cephalograms, extraoral and intraoral photographs were taken for each patient. Regular follow-ups were done in the course of treatment. Since the compliance of the patient is of prime importance during the treatment period, a follow-up chart was prepared and monitored periodically to assess compliance by each patient, and the patients were motivated to wear the appliance regularly. The final cephalogram of all the subjects was taken at the end of the 15-month treatment period.

To have standardized cephalometric radiographs, it becomes important that all the radiographs should have similar patient orientation and also the same amount of magnification. For this purpose, all the lateral cephalometric radiographs were taken from the standardized Planmeca Proline EC cephalostat machine on a standard Kodak C-MAT Green sensitive 8 x 10-inch film with an anode-to-midsubject distance of 5 feet and with the Frankfort-Horizontal plane parallel to the floor and lips in repose. All the radiographs were traced on a standard matt acetate tracing paper in a random order by a single operator in order to reduce bias.

Twenty-seven landmarks were identified on each cephalogram and were grouped as follows:

The mean and standard deviations were calculated for each cephalometric variable. The mean differences between the pretreatment and post-treatment measurements and [SUPPORTING:1] the measurements of the first and second observation periods for the control group were evaluated using the paired t test. Student t test was applied for comparison of the groups. To determine the accuracy of the method, 10 cephalograms were randomly selected and retraced after a period of 20 days. A paired t test was applied to the first and second measurements, and the difference was found to be insignificant

 Results



The results of the present study can be presented under the following headings:



Comparison between the pretreatment and post-treatment changes in the control groupComparison between the pretreatment and post-treatment changes in the treatment groupComparison of the post-treatment changes between the treatment and control groupsComparison between the pretreatment and post-treatment changes in the control group

Comparison between the pretreatment and post-treatment skeletal (angular) measurements in the control group

Comparison between the pretreatment and post-treatment values showed a significant difference for SNB and Ar-S-N (P . There was no significant difference for the remaining parameters (P ≥ 0.05).

Comparison between pretreatment and post-treatment skeletal (linear) measurements in the control group

Comparison between the pretreatment and post-treatment values showed a significant difference for Go-Me, Co-Gn, Co-A and Go-Pc (P . There was no significant difference for the remaining parameters (P ≥ 0.05).

Comparison between pretreatment and post- treatment dental measurements in the control group

Comparison between the pretreatment and post- treatment values showed a significant difference for only L1-NB linear (P . There was no significant difference for the remaining parameters (P ≥ 0.05).

Comparison between the pretreatment and post-treatment changes in the treatment group

Comparison between pretreatment and post-treatment skeletal (angular) measurements in the treatment group

Comparison between the pretreatment and post-treatment values showed a significant difference for SNA, SNB, ANB, SN-GoGn and Gn-Go-Ar (P . There was no significant difference for the remaining parameters (P ≥ 0.05).

Comparison between pretreatment and post-treatment skeletal (linear) measurements in the treatment group

Comparison between the pretreatment and post-treatment values showed a significant difference for all the parameters (P P . There was no significant difference for the remaining parameters (P ≥ 0.05).

Comparison of the post-treatment changes between the treatment and control groups

Comparison of post-treatment skeletal (angular) measurements between the treatment and control groups [Figure 1]

Comparison of the post-treatment values between the treatment and control groups showed a significant difference for ANB and OP-SN (P . There was no significant difference for the remaining parameters (P ≥ 0.05).

Comparison of post-treatment skeletal (linear) measurements between the treatment and control groups [Figure 2]

Comparison of the post-treatment values between the treatment and control groups showed a significant difference for Ramus height, N-Me and Go-Ar (P . There was no significant difference for the remaining parameters (P ≥ 0.05).

Comparison of post-treatment dental measurements between the treatment and control groups [Figure 3]

Comparisons of the post-treatment values between treatment and control groups showed a significant difference for L1-NB angular and overjet (P . There was no significant difference for the remaining parameters (P ≥ 0.05).

 Discussion



On comparison of the changes due to treatment with those due to growth, ANB (maxillo-mandibular relation) and OP-SN (cant of occlusal plane) were reduced significantly in the treatment group as compared to the control group. This indicates that there was a significant reduction in the skeletal class II relationship in the patients wearing preorthodontic trainer. There was also an upward cant of the occlusal plane in the treatment group, probably due to the forward rotation of mandible. This is in agreement with the findings from the study by Usumez et al. [7] and Oliveira et al., [8] who observed that in patients who had worn trainers, there was forward rotation of mandible accompanied by an increase in its sagittal growth, leading to forward positioning of the mandible.

Height of the ramus (Ramus height, Go-Ar) and anterior facial height (N-Me) were significantly increased in the treatment group as compared to the control group, indicating that there was a significant increase in the vertical dimensions of the face in general and the mandible in particular with the use of preorthodontic trainer. Both the anterior and posterior facial heights were increased significantly. This is in accordance with the findings from the study by Usumez et al. [7] and Oliveira et al., [8] who concurred that there was an increase in facial height in patients who had worn preorthodontic trainer.

On comparison of the dental parameters, significant reduction in the overjet and an increase in the inclination of mandibular incisor (L1-NB deg) in the treatment group were observed as compared to the control group. This indicates that on utilization of the preorthodontic trainer, there is decrease in the overjet accompanied by forward positioning of the mandibular incisor. This concurs with the findings from the study by Usumez et al., [7] who ascertained that there was increased lower incisor proclination, retroclination of upper incisors and reduction in overjet in the subjects using preorthodontic trainer.

 Conclusion



The treatment of class II division I malocclusion with preorthodontic trainer appliance for a period of 15 months produced the following changes:



A significant reduction in ANB and OP-SN values was noted, indicating a significant reduction in the skeletal class II relationship in the patients wearing preorthodontic trainer.There was a significant increase in the vertical dimensions of the face in general and the mandible in particular with the use of preorthodontic trainer. A significant increase in both anterior and posterior facial heights was noted.On utilization of the preorthodontic trainer, there was decrease in the overjet accompanied by forward positioning of the mandibular incisors.This present study suggests that class II corrections can be achieved with the preorthodontic trainer appliance. This appliance appears to have mostly dentoalveolar effects with smaller but significant skeletal effects

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