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SOFT- AND HARD-TISSUE CHANGES FOLLOWING TREATMENT OF CLASS II DIVISION 1 MALOCCLUSION WITH TWIN BLOCK- A RANDOMIZED CONTROL TRIAL
Corresponding Author : Dr. Richashree
This article was originally published by Indira Gandhi Institute of Medical Science and was migrated to Scientific Scholar after the change of Publisher.
Abstract
Background:
The purpose of this study was to examine change in soft tissue and hard tissue profile of class II div 1 malocclusion patients. Lateral cephalogram of the patients were obtained at the time interval of T1 and T2. Material method- 30 class II div 1 patients were examined. Out of which 17 were girls and 13 were boys. Skeletal, dentoalveolar and soft tissue were analysed using lateral cephalogram of the patient.
Result:
Pre and post treatment cephalogram analysis show a significant change in SNB, ANB, Z angle and upper lip measurement.
INTRODUCTION:
Kingsley was the first to use the appliance for forward positioning of mandible in the year of 1879. Appliance introduced by Kingsley consist of clasps on molars, labial wires and a bite plane extending posteriorly1. Myofunctional appliance was introduced by Robin 1902 and Andresen 1908. Myofunctional appliance enhances the mandibular growth in class II patient. Large scale of functional appliances has been put forward to amplify the mandibular growth and correct bite by forward positioning of mandible2-6. Refinement of facial aesthetic is a key to success of orthodontic practice. The contemporary paradigm of soft tissue enhancement underlines the importance of this issue7. One of the most frequently occurring orthodontic condition is class II div 1 malocclusion. This particular malocclusion is about 20%-30% of all orthodontic patients8. Class II malocclusion is characterised by retrognathic mandible, anterior displacement of the maxilla, increased vertical dimension of posterior maxilla, mandibular fossa in posterior position, maxillary constriction and a combination of factors. In general, maxillary and mandibular incisors are well-positioned, differently from maxillary incisors which tend to be protrusive 9-12. Characteristic features of class II div 1 malocclusion includes retrusive chin, convex profile, incompetent lips and deep mentolabial sulcus13. Such condition leads to negative psychological consequences and reduced self-confidence of patient14. Some published article suggests that myofunctional appliances are considered to be effective in improving overjet 15-18. According to some authors treatment timing plays a significant role in supplementary lengthening of mandible when functional appliance is opted at pubertal growth spurt 19,20.
MATERIALS AND METHODS:
The sample size consists of 30 patients. Out of which 17 were girls and 13 were boys. Mean age was 9.8 years + 14 months and 11.2 years +14 months respectively. Twin block appliance was fabricated using adams clasps on upper first molar labial bow in the upper arch. In the lower arch adams clasp was fabaricated on premolar and ball end clasp was given in between lower central incisor and between canine and lateral incisor on both the quadrant. The active phase of the treatment lasted about 14 + 2 months.
Inclusion criteria
Class II molar relation
Class II canine relation
Class II skeletal pattern
Reterognathic mandible
Orthognathic maxilla
Overjet more than 4mm
Exclusion criteria
Craniofacial syndrome
Congenitally missing tooth
Lower incisor protrusion
No history of previous orthodontic treatment
Patients were instructed to wear the appliance full time except for meals and brushing. Bite registration at the start of treatment was kept with 4mm advancement, further increments were added depending on the overjet. Amount of vertical opening was according to the freeway space i.e., 2-4mm beyond it. Treatment was continued till the time patients achieved class I molar relationship and overjet of 2mm. upper inclined plane was given post twin block appliance.
Standardized lateral cephalogram, dental cast and photograph were obtained twice at T1 before the start of the treatment and T2 after the treatment. Various skeletal, dental and soft tissue measurements were taken. Lateral cephalometric radiographs taken at T1 & T2 were traced and the values were measured. In order to evaluate various soft tissue and hard tissue landmarks.
Measured data were analyzed using SPSS software version 22 (SPSS Inc, Chicago, IL, USA). P value <0.5 was considered to indicate statistical significance.
RESULT:
In this research, 30 patients treated with twin block were evaluated pretreatment and posttreatment. The paired t- test is used evaluation of pretreatment and posttreatment cephalometric measurements. Table 1 and table 2 shows soft tissue and hard tissue change before and after the treatment respectively.
Variables | Pretreatment (T1) | Posttreatment (T2) | P Value |
Upper lip thickness | 12.6 ± 1.8 | 14.8 ± 1.4 | 3.388-E05 |
Lower lip thickness | 13.6 ± 1.4 | 15.1 ± 1.2 | .0004 |
Pog-Pog' | 11.8 ± 1.5 | 13.5 ± 2.3 | .0086 |
Me- Me' | 7.4 ± 1.6 | 8.8 ± 1.3 | .0019 |
Nasolabial angle | 103.5 ± 6.8 | 106.4 ± 7.7 | .1937 |
Interlabial gap | 3.3 ± 1.3 | 2.4 ± 1.1 | .0214 |
Upper lip -E line | -0.72±2.12 | -2.37±2.32 | 0.000* |
Lower lip- E line | 0.01±2.96 | -1.38±2.82 | 0.001* |
Z-angle | 66.44±7.63 | 70.60±6.47 | 0.001* |
Variables | Pretreatment | Posttreatment | P value |
SNA | 81.64±2.31 | 81.84±2.19 | 0.632 |
SNB | 76.20±2.48 | 78.12±2.59 | 0.000* |
ANB | 5.48±1.71 | 3.72±1.65 | 0.000* |
Incisal inclination | 85.92±2.29 | 85.72±3.06 | 0.664 |
Overjet | 6.42±2.42 | 3.72±1.57 | 0.000* |
Overbite | 4.26±1.95 | 3.11±1.63 | 0.007* |
IMPA | 94.22±6.67 | 95.92±7.35 | 0.089 |
N-Pog | 9.64±4.42 | 6.96±4.25 | 0.000* |
As illustrated in table 1 it signifies significant change from pre posttreatment values of upper lip -E line, lower lip- E line and Z - angle (P<0.001) was seen .
DISCUSSION:
Using functional appliances therapy not only bring about skeletal and dental changes but it also brings about change in soft tissue profile of the patient. At the same time opting functional appliance eliminates the need of extraction. The aim of this research was to evaluate the effect of myofunctional appliance on soft issue and hard tissue in growing individuals. Facial appearance plays a major role in social well- being of individuals. Many researchers shows that the stretch of the muscles and the adjacent soft tissues of the facial skeleton leads to repositioning of the forward shift of mandible to its original place also causing headgear effect on maxilla21,22. In our research it was observed that a significant change was noted in upper lip to E line, lower lip to E line and Z angle. Hard tissue evaluation states significant change in SNB, ANB, overjet, overbite and N-Pog. Illing et al 23 in his study rooted that there is more pronounced reduction in the inclination of maxillary incisors with twin block group compared to that of bass and bionator group.
In our research upper incisor to palatal plane, showed significant reduction from pretreatment to post treatment.
CONCLUSION:
The conclusion of our research is myofunctional appliance (twin block) bring about change in hard tissue and soft tissue. Patient"s facial esthetics improves. Since, treatment was started at the growing phase so, change in mandibular length was observed. which was also due to true mandibular growth anf repositioning of mandible also.
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