6-6- 24 soft tissue retraction ORTHODONTICS.pptx

ARTICLES TO SHOW SOFT TISSUE CHANGES AFTER EXTRACTION IN ORTHODONTICS

1. AJODO,1987 The purpose of this study was to improve the clinician’s ability to predict the soft-tissue profile changes caused by retraction of the maxillary incisors by quantifying the profile changes, and identifying the contribution of the most significant factors responsible for these changes.

2. T he orthodontist is often confronted with the need to predict soft-tissue profile changes that may result from orthodontic treatment. The problem arises because the contribution of many of the factors influencing the soft-tissue profile is not fully understood. The complexity of the problem is increased in growing patients in whom the post treatment soft-tissue profile is the result of both growth and orthodontic treatment.

3. the majority of investigations into soft-tissue profile changes caused by orthodontic treatment : (1) have used small samples that prevented both adequate sample segregation and reliable statistical analysis, ( 2) have used superimposition techniques that were sometimes questionable , ( 3) have paid little or no attention to the vertical dimension, thus limiting their findings to changes taking place in the anteroposterior direction.

4. Other major problems were (1) inability to discriminate between the effect of growth and treatment because of lack of good control samples of untreated subjects ( 2) the fact that, with the exception of some studies the tension in the lips when the cephalometric radiographs were taken was neither controlled nor evaluated

5. MATERIAL AND METHOD 133 white female subjects were studied. The study sample comprised 80 Class II, Division I subjects who had undergone orthodontic treatment The control sample comprised the remaining 53 subjects who had received no orthodontic treatment a multibanded edgewise appliance for an average period of 27 months for growing subjects and 30.1 months for adult subjects . Ten subjects were treated on a nonextraction basis. In the remaining 70, various teeth were extracted. Both extraction and nonextraction subjects exhibited a minimum amount of 3 mm of maxillary incisal edge retraction at treatment completion. subjects ware selected based on: age and skeletal pattern using the upper facial height (N-ANS), the lower facial height (ANS-Me), and the anteroposterior locations of landmarks subnasale (A) and supramentale (B) as parameters . Each one of these control subjects was carefully matched to a subject of a similar age in the study group using all four parameters with a range not exceeding 1.5 mm for each parameter.

6. CEPHALOMETRIC ANALYSIS The two reference lines : The “X” axis is a line drawn from the landmark sella on the pretreatment cephalogram at 7 ° inferior to the original sella-nasion line . The “Y” axis is a line drawn from the landmark sella at 90° to the “X” axis.

7. LIP RETRACTION Labrale superius Labrale inferius

8. LIP THICKNESS 5: labrale superius 19: upper incisor labial crown point 9 : labrale inferius 22: lower incisor labial crown point

9. LIP LENGTH 3: subnasale 6: upper stomion 8: lower stomion 10: lower labial sulcus

10. NASOLABIAL ANGLE 30: columella 3: subnasale 5:labrale superius

11. STATISTICAL ANALYSIS The mean and standard error for each of the dependent variables for each of the four age groups were calculated for the control sample. These means are considered to measure the growth effect for each of the four age groups. The growth effects as calculated in step 1 were subtracted from the observed values of each of the dependent variables for each of the growing subjects in the study sample . The growth effects subtracted were those corresponding to the age group of that subject. The resultant differences are considered to be the pure effects of the treatment on each of these variables.

12. RESULTS Changes in the control sample are shown to be caused by growth only whereas changes in the study sample are shown to be caused by both growth and orthodontic treatment

13. The interpretation led to the following conclusions: In general, only minimal changes (less than 2mm for linear measurements and 5° for angular measurements) occurred as a result of growth itself in the soft-tissue variables. The changes in the anteroposterior position of the upper lip as a result of growth itself were minimal. On the other hand, a significant retraction of the upper lip occurred (mean of 3.7 mm) when orthodontic treatment was performed . The anteroposterior position of the lower lip seemed to remain almost unchanged in both samples.

14. Although the nasolabial angle remained almost unchanged in the control sample, it increased substantially (by a mean of 10.5°) in the study sample. The interlabial gap decreased by a small amount (mean of 1.2 mm) with growth. The amount of this decrease almost doubled with orthodontic treatment. The length of the upper lip remained almost unchanged in both samples. The lower lip length showed a marginal increase in the control sample, while it increased substantially in the study sample (by a mean of 3.4 mm).

15. The thickness of the lower lip remained almost unchanged in both samples . The upper lip thickness , which also remained unchanged in the control sample, increased by a mean of 2.3 mm in the study sample . The soft-tissue lower facial height increased marginally in the control sample and slightly more in the study sample . Only three demonstrated change that is clinically significant. These measurements are the upper lip retraction, the increase in the nasolabial angle, and the increase in the lower lip length .

16. DISCUSSION UPPER LIP RETRACTION : an average retraction of the maxillary incisors of 6.7mm , caused the upper lip to retract by an average of 4.3mm when changes caused by growth were eliminated.

17. The results of this study agreed with those of Wisth ,who found that the initial overjet is not an important factor in the upper lip retraction . This study did not agree, however, with Oliver , who found that a greater amount of upper lip retraction took place with thinner upper lips pretreatment . The results also could not confirm the finding of Rains and Nanda that mandibular rotation had a great influence on the upper lip retraction

18. NASOLABIAL ANGLE : The size of the nasolabial angle, which remained almost unchanged due to growth itself, increased substantially (by an average of 10.5°) with orthodontic treatment including an average maxillary incisal edge retraction of 6.7mm

19. This study did not agree with Waldman ,who did not find any significant correlation between the horizontal retraction of the maxiilary incisors and the increase in the angle . It also did not agree with the ratios established by Lo and Hunter between the increase in the nasolabial angle and retraction of the maxillary incisal edge ( 1.6° for each 1 mm in their study and only 0.8° for each 1 mm in our study) The increase in the angle and the size of the lower facial height ( 2.2° for each 1 mm in their study and 3° for each 1 mm in our study ). Lo and Hunter also reported that for every 1° increase in the Frankfort mandibular plane angle, the nasolabial angle increased by 3° on average. That finding was not supported by this study.

20. LOWER LIP LENGTH : The increase in the lower lip length was significant at the clinical level lower lip is the major contributor in both the interlabial gap reduction and the increase in the lower soft tissue component with orthodontic treatment.

21. CONCLUSION In general, growth was associated with only minimal changes in the soft-tissue profile. The three clinically significant soft-tissue changes that occurred in response to orthodontic treatment were the retraction of the upper lip , the increase in the lower lip length, and the increase in the nasolabial angle The possible variation in soft-tissue response to orthodontic treatment should be discussed with the patient before the initiation of any orthodontic procedure.

22. British Journal Of Orthodontics, 1974 Aim:- To describe the lip morphology and treatment changes in two groups of boys with slight and marked overjet.

23. Materials and Methods They took 60 boys treated at the orthodontic department, University of Bergen. They were 11-12 years at the start of the treatment, and 13-14 years at the time of end of the treatment. Only individuals with competent lips were included. They all should have a normal overbite and an overjet of either 3-4 mm (Group A) or 8-10 mm (Group 8)

24. Results During pre treatment Lip morphology showed a significantly different lower lip morphology with a more acute lip and a deeper sulcus in group B. The thickness of the lower lip was greater and the lip protrusion angle was more acute. The upper lip morphology was approximately similar in both groups.

25. During treatment M ean changes in lip morphology was generally greater in group B. O nly significantly different change was a greater increase of the interincisor angle in group B. Group Upper incisor retraction Upper lip retraction Group A (3-4mm) 2 mm 1mm Group B (8-10mm) 6mm 2.5mm

26. C onclusions The upper lip morphology was approximately similar in both groups while the lower lip of individuals with great overjet had a deeper mentalis sulcus, an acute sulcus angle and thicker vermilion area of the lower lip . The upper lip response was more closely related to the degree of incisor retraction in individuals with a small overjet. In the group with great overjet the lower lip response was almost as great as the upper lip change.

27. The variability of the results was great and indicates that prediction of soft tissue changes in an individual case is impossible, particularly if the overjet is great. Correction of a severe malocclusion is no guarantee for favorable soft tissue changes.

28. British journal of orthodontics, 1975 Aim : The object of this study is to determine changes in hard and soft tissue profile which occur in Class II Division 1 incisor relation cases as a result of overjet reduction.

29. Material and Method 33 Patient with class II div1 type incisor relationship were selected. 14 males with age of 13 years 1 month and 19 females with an average age of 13 years. The overjet ranged from 3·0 mm- 12·0 mm with an average of 6·99 mm. Cephalomteric radiographs were taken for further assesment .

30. R esult Retraction of upper incisor was attempted in all cases while In 23 cases retraction of 10.8⁰ was seen. 26 cases showed inter incisal angle increased by 12.3⁰ Overjet ranged from 1-7mm with average being 3.44 The difference between the male and female average angles, while small in value, suggests a difference in growth at pogonion , due to the length of the N to Pg line. mandibular growth in males averages twice that in females

31. From the above table in females, either Class I or Class II dental relationships there is a relationship between retraction of the upper incisors and a reduction in the prominence of the lower lip. a correlation between retraction of the upper incisors and a decrease in the prominence of the upper lip in females with a Class I dental relationship was also noticed.

32. Conclusion This study therefore confirms the clinical impression that orthodontic treatment aiming to retract the upper labial segment alters the lip posture so changing the facial appearance. In females growth has been completed more nearly by the age at which they were examining patients, whereas in the male growth is progressing and therefore the lips continue to grow forward, so altering the values for the facial angle.

33. AIM : To see the postural changes that have occurred in the upper lip with retraction of maxillary incisors in class II div 1 cases. The Angle Ortho, 1982

34. MATERIAL AND METHOD: The reference line PM, is a vertical line marking the posterior margin of the maxilla. It is defined above by a point of intersection of greater wings of sphenoid with the floor of anterior cranial fossa , and below by inferior point on pterygomaxillary fissure. Lip and tooth retraction were measured linearly parallel to neutral occlusion line which is constructed perpendicular to PM. Axial inclinations of incisors were also measured from this line.

35. MEASUREMENTS CONSISDERED ARE: Change in horizontal position of maxillary incisal edge. Linear horizontal change of labiale superiorus . Change in nasolabial angle. Change in axial inclination of maxillary incisors. Palatal tilt.

36. RESULTS: There was no significant correlation between horizontal movement of edge of maxillary incisors along the neutral occlusal line and change in nasolabial angle. In the 41 cases reported, the average retraction of lip was 1mm with an average incisor retraction in the horizontal plane of 3.8mm , for a ratio of 1:3.8.

37. A positive relationship was found between angulation of palate to PM and the nasolabial angle. A more obtuse nasolabial angle can be expected with steeper angulation of palate. There was a significant correlation between the change in the angulation of the maxillary incisor and nasolabial angle.

38. SUMMARY: Patients with large palatal tilt angles showed larger changes in the nasolabial angle with incisor retraction. Nasolabial angle is increased with uprighting ( lingual tipping ) of the incisors. A ratio of 1:3.8 was found between lip retraction and incisor retraction.

39. AM.J.ORTHOD.,1982 The purpose of this study is to investigate the changes in nasolabial angle owing to growth without treatment, for comparison with changes in nasolabial angle and lip thickness resulting from maxillary incisor retraction.

40. MATERIALS AND METHOD Participants: 93 Caucasian children aged 9 to 16 years. Treatment Group: 25 boys and 25 girls Untreated Group: 25 boys and 18 girls Treatment Group Details: Condition: Class II, Division 1 malocclusions. Criterion: Minimum of 3 mm upper incisor retraction at treatment completion. Average Overjet: Boys: 6.5 mm, Girls: 7.4 mm. Mean Age Before Treatment: 12 yrs. Mean Age After Treatment: 14 yrs

41. MATERIALS AND METHOD Untreated Group Details: Condition: Class II, Division 1 malocclusions. Criterion: Minimum of 4 mm anterior overjet. Average Overjet: Boys: 5.5 mm, Girls: 6.3 mm. Mean Age: 13 yrs. Radiographs: Both groups: Radiographs displayed a relaxed lip posture. Interlabial Gaps: Treatment Group: 20 boys and 22 girls had interlabial gaps. Untreated Group: 12 subjects had no interlabial gaps

42. RESULTS Untreated Group : NLA was found to be 106.10 degrees ±12.40 degrees from 9 to 16 years of age, with no significant age change. Treatment Group: Significant correlation between NLA and various skeletal landmarks, especially Is, LFH, and MPA. Nasolabial Angle Correlations: High correlation with Is retraction (r = 0.77). Each mm of Is retraction increased the nasolabial angle by 1.63 degrees. 90% of nasolabial angle increase related to lip retraction, 10% to nasal slope change. LFH Correlation Increase in nasolabial angle by 2.2 degrees for each mm increase in LFH.

43. Vertical Growth Patterns: Vertical growth pattern increased nasolabial angle by 3.2 degrees more than normal growth. Horizontal growth pattern decreased nasolabial angle by 3.2 degrees compared to normal growth. MPA Correlation: Each degree increase in MPA resulted in a 2.9-degree increase in the nasolabial angle. Soft-Tissue Landmark Changes - Highest correlation between labrale superius (Ls) and Is retraction. For every 2.5 mm of retraction of Is, Ls moves by 1 mm. in the same direction. No Significant Sex Differences or treatment method differences are seen

44. Summary The nasolabial angle does not change significantly with growth in untreated samples. Significant increase in nasolabial angle correlates with the amount of maxillary incisor retraction during treatment. Increase in nasolabial angle accompanies increases in lower face height and mandibular plane angle during treatment. Study provides predictive values for changes in nasolabial angle, indicating significant control over the soft-tissue profile by the orthodontist. Vertical growth patterns result in a higher increase in nasolabial angle, while horizontal growth patterns result in a lower increase, compared to normal growth patterns.

45. The aim of the present study is to evaluate vertical lip changes in relation to variations in dental height, overjet, and overbite following orthodontic treatment. American Journal of Orthodontics, 1983

46. MATERIAL & METHODS:- - Study on 22 male patients aged 18-20 with Class II, Division 1 malocclusion - Pre- and posttreatment cephalometric radiographs analyzed - Radiographs taken with the same apparatus for consistency and treatment involved extraction of the four first premolars

47. The following specific reference points were located and marked on the pre- and posttreatment roentgenograms Labrale superius (LS)-The most anterior point on the convexity of the upper lip. Labrale inferius (LZ)-The most anterior point on the convexity of the lower lip. Maxillary central incisor (I)-The incisal tip of the most inferior and anterior maxillary central incisor. Mandibular central incisor ( i )-The incisal tip of the most superior and anterior mandibular central incisor Infradentule (Id)-The highest interdental point on the alveolar mucosa in the median plane between the mandibular central incisor. Prosthion ( Pr )-The lowest interdental point on the alveolar mucosa in the median plane between the maxillary central incisors. The reference line (RL) was adopted as the line drawn through points nasion (N) and pogonion (Pg)

48. The reference line was constructed on the posttreatment film by drawing line sella -nasion (S-N) on the film and then duplicating angle S-N-Pg of the pretreatment film on the posttreatment film, the vertical arm of the constructed angle becoming the reference line.

49. Overjet-The horizontal distance between I and i along the perpendicular to the RL Overbite-The vertical distance between 1 and i along the perpendicular to the RL Dental height-The vertical distance between Pr and Id along the perpendicular to the RL Vertical lip height-The vertical distance between LS and LI along the perpendicular to the RL

50. The changes in overjet and overbite with the retraction of upper and lower incisors following orthodontic treatment and the subsequent changes in dental height and vertical lip height were calculated. Increase in diff: + Decrease in diff: -

51. SUMMARY 1. Dental height is reduced significantly with orthodontic treatment. A reduction of 1 mm. in dental height is accompanied by an average reduction of 3.98 mm. in overjet and 2.17 mm. in overbite . 2. Vertical lip height increases with treatment , but the increase is statistically insignificant at the 1 percent level. 3. Vertical lip height increases while dental height decreases with treatment. The correlation is statistically insignificant, however. 4. The increase in vertical lip height is significantly dependent on the reduction in overjet.

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