Extraction and non extraction (1)
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This document discusses factors that orthodontists consider when determining whether to extract teeth as part of orthodontic treatment. It outlines general factors like medical conditions, age, and pathology, as well as factors specific to the malocclusion like the skeletal pattern, degree of crowding, overjet, and overbite. Diagnostic elements that can influence the decision for extractions include issues with compliance, the tooth-arch discrepancy, cephalometric measurements and facial profile, growth stage, and dental asymmetries. Sound decision-making relies on evaluating these elements to determine the best treatment approach.
Extraction and non extraction (1)
- 1. Extraction And Non- Extraction DR. SALAHEDDIN DAHBOUR SUPERVISED BY: DR. AHMAD AL TARAWNEH DR. RAGHDA SHAMOUT DR. ANWAR AL RAHAMNEH
- 2. Why we take out teeth? General problems: caries, periodontal problems, and sever malpostioned teeth. Correction of incisor relationship and OJ. Relief of crowding. OB correction (flattening Curve of Spee). Facial esthetics (bimaxillary proclination). To allow distalization. Tooth size anomalies. Interceptive treatment. Stability.
- 3. Advantages of non-extraction approach Less trauma to the child. Easier to treat. Short duration. Facial fullness to give young full profile. Less effect on TMJ. Less effect on vertical relationship. Less effect on smile width.
- 4. Advantages of extraction approach Stability Less protrusive facial appearance. Controllable outcomes. Little gingival recession.
- 5. Factors affecting the choice of extractions in orthodontics
- 6. General Factors Medical condition. Age of patient - more difficult to close space in older pts. Also in young patient other method of space provision can be used. Patient cooperation where other method of space provision can be used. Pathology. Gross Displacement. Abnormal morphology.
- 7. Factors specific to the malocclusion Patient’s facial aesthetics and profile. The A-P skeletal pattern. The vertical skeletal pattern. Extraction avoided in deep bite and vice versa. The transverse relationship of the arches. Will Andrews and Larry Andrews' WALA line is the band of soft tissue immediately superior to the mucogingival junction in the mandible. It is at or nearly at the same superior-inferior level as the horizontal centre-of-rotation of the teeth. Andrews' sees the WALA Ridge as the primary landmark for arch width and form and for archwire width and form. This is perhaps a better indicator of mandibular basal bone position than the pretreatment mandibular arch width.
- 8. WALA Ridge
- 9. The degree of crowding. 1. Mild , 1 to 4mm, Non extraction. 2. r Moderate, 5 to 8 mm, borderline case. 3. Severe, 9+ mm, extraction. Site of crowding. Amount of overjet. Amount of overbite. Also space might be required to flatten the COS.
- 10. The inclination of the canines. Amount of space needed for correction of the molar relationship. Amount of space for centreline correction. Treatment plan and aim: surgical treatment plan or camoflagable. Treatment mechanics: which determines the anchorage requirements of the proposed tooth movements.
- 12. Certain malocclusions require orthodontists to be capable of establishing a diagnosis in order to determine the best approach to treatment. The purpose of this article was to present clinical cases and discuss some diagnostic elements used in drawing up a treatment plan to support tooth extraction. All diagnostic elements have been highlighted: Issues concerning compliance, tooth-arch discrepancy, cephalometric discrepancy and facial profile, skeletal age (growth) and anteroposterior relationships, dental asymmetry, facial pattern and pathologies. We suggest that sound decision-making is dependent on the factors mentioned above. Sometimes, however, one single characteristic can, by itself, determine a treatment plan.
- 13. COMPLIANCE All orthodontic treatment requires patient compliance, for example, maintaining adequate oral hygiene, not breaking or damaging the orthodontic accessories, or simply attending regular appointments. Certain types of malocclusion, however, require additional compliance to ensure treatment success. At first, it is extremely difficult to determine whether or not a patient will cooperate, but by observing certain criteria, such as patient behavior in the office, the nature of their relationship with their escort and through an interview with the parents, we can venture some predictions regarding compliance.
- 14. Class II malocclusions with an adequate lower arch can be corrected by moving the upper teeth distally with the use of elastics or headgear. Both require substantial patient compliance. Alternatively, distal movement can be achieved with mini-implant support, or orthodontic correction can be accomplished by extracting upper premolars, which requires virtually no patient cooperation. Some treatment plans can achieve similar results whether conducted with or without extractions (especially borderline cases). However, others may have their treatment outcome jeopardized if planning was based on patient dependent mechanics and the patient failed to respond accordingly on.
- 15. TOOTH-ARCH discrepancy This discrepancy should be evaluated in both the upper and lower arches. But for diagnostic purposes, the lower arch is a priority because of greater difficulty in obtaining space. When orthodontists are faced with a marked negative tooth-arch discrepancy (TAD) in the lower arch, they will be hard pressed to treat the patient by performing tooth extractions. Small negative discrepancies can, in most cases, be treated without extractions. Thus, space can be obtained by using leeway space (if still possible), stripping, correction of pronounced mesial tipping of lower posterior teeth and small expansions and/or protrusions with the goal of restoring normal tipping to the lower teeth, especially if accompanied by rapid maxillary expansion (RME).
- 16. case 1 This case illustrates the situation of using leeway space to avoid extractions. 9 year-old patient had a negative discrepancy in the upper and lower arches. To solve this case, we could choose for upper and lower premolar extractions. Although the profile was slightly convex, we opted for treatment using leeway space in the lower arch, placement of lingual arch during the mixed dentition and rapid maxillary expansion in the upper arch. With this therapeutic approach we achieved tooth alignment without the need to perform extractions and obtained a straight profile, which probably would have been in worse shape if the case had been conducted with tooth extractions.
- 20. case 2 Another situation typical of negative discrepancy cases is when the need arises to perform tooth extractions but no changes can be made to the facial profile. The patient’s facial profile was straight with negative discrepancy in the upper and lower arches and asymmetry in the lower arch with lower midline shift to the right. To solve this case we chose to extract three premolars (14, 24 and 34). To avoid excessive retraction of anterior teeth towards lingual and deepening of the profile, we used resistant torque in the upper and lower teeth during retraction and avoiding incisor uprighting. The result at the end of treatment was dental harmony in the existent space, with maintenance of the facial profile.
- 24. Zero or positive model discrepancies require that treatment be performed without extractions, unless the patient has some other associated problem that indicates extraction. Proffit and Fields developed a guide of contemporary procedures for evaluating extraction in Class I cases with crowding and/ or protrusion. The authors reported that in negative lower arch discrepancies below 4 mm tooth extraction is rarely required, except in cases of incisor protrusion or posterior vertical discrepancy.
- 25. Negative discrepancies in the lower arch between 5 mm and 9 mm allow treatment to be performed with or without extractions, depending on the characteristics of the patient and the orthodontic mechanotherapy that was used. Finally, for negative discrepancies of more than 10 mm extraction is almost always required, preferably of first premolars because second premolar extraction is not suitable for large discrepancies.
- 26. When deciding to solve a TAD with extractions, changes in the profile due to retraction of anterior teeth and likely decrease in the lower face should be considered. But if the decision is for addressing the negative TAD without extractions, the likelihood of an increased lower face caused by the distal movement of posterior teeth in order to create space should be taken into account.
- 27. CEPHALOMETRIC DISCREPANCY (CD) AND FACIAL PROFILE In situations of pronounced labial tipping of the incisors with a high CD and expressive facial convexity, extractions are often necessary to retract these incisors, improving the patient’s profile. The current trend in orthodontic diagnosis is to focus more on facial features and rely less on cephalometric measurements. Therefore, sometimes a case is finished with protrusive incisors so as not to alter a satisfactory profile, whereas one can resort to stripping to create spaces that would allow these teeth to be slightly uprighted.
- 28. Certain profile changes expected during orthodontic treatment do not always occur. (Boley et al). Patients can have different degrees of concave or convex profiles (strong, moderate or mild) or straight profiles. According to the profile type, one can determine the need for extractions in orthodontic treatment because the profile will respond to the changes effected in the teeth.
- 29. According to Ramos et al, for each 1 mm of retraction of the upper incisor the upper lip retracts 0.75 mm. Other authors found lower values for this ratio (1/0.64 - Talass et al; 1/0.5 – Massahud and Totti). Regarding the lower lip, for every 1 mm of lower incisor retraction, it retracts 0.6 mm or 0.78 mm. Thus, space closure performed by retracting anterior teeth tends to render the profile more concave.
- 30. There are situations where although the facial profile is concave, orthodontic planning indicates extraction in order to address issues of crowding and/or anteroposterior dental asymmetries. It is noteworthy that facial esthetics is increasingly valued by patients and that facial profile becomes more concave with age. Cases should therefore be preferably finished with slightly protruding profiles to prevent them from becoming concave in future. Adult patients should avoid excessive relocation of anterior teeth towards lingual for it may highlight creases and wrinkles, and impart an immediate perception of facial aging.
- 31. case 3 patient aged 11 years, convex profile, skeletal Class II (ANB = 6º), dental Class I, zero lower TAD, 2 mm overjet, 3 mm open bite, well positioned upper incisor (1. SN = 103º) and protruding lower incisor (IMPA = 110º). As aggravating factors, the patient presented with mouth breathing and difficulty in sealing the lips. Also noticeable were an increased lower facial third and lack of space for eruption of maxillary canines.
- 34. Based on these assessments, we opted for orthodontic treatment combined with extractions of teeth 14 and 24 with the goal of aligning and leveling the upper canines and teeth 35 and 45 for lower incisor retraction and mesial movement of teeth 36 and 46. A vertical chin cup was also used during nighttime for vertical control, thereby avoiding extrusions. At the end of treatment there was improvement in the facial profile and correction of dental relations. The final profile was not fully repositioned and was finished with a slight protrusion in order to avoid the premature aging of the patient.
- 37. Skeletal age (GROWTH) AND AnteroPosterior RELATIONSHIPS In malocclusions with skeletal discrepancies it is crucial—for the diagnosis and prognosis of the case—to check whether the patient is still undergoing significant facial growth. Maximum pubertal growth spurt occurs approximately at around 11-12 years in girls and 13-14 years in boys, subject to individual variations. The most widely used method for assessing skeletal age is through a hand and wrist radiograph, by analyzing the size of the epiphyses relative to the diaphysis. If a malocclusion can be corrected with growth response (growth redirection), clinicians can handle the case without extractions.
- 38. Case 4 This 11 year-old patient had a convex profile, Skeletal Class II (ANB = 8º), Angle Class II, division 1, 2 mm lower TAD, 8 mm overjet, 5% overbite, well positioned upper incisors (1.SN = 101º), protruding lower teeth (IMPA = 99) and increased lower facial third. As an aggravating factor, the patient had a thumb-sucking habit, mouth breathing and a predominantly vertical resultant growth (SN.GoGn = 40º).
- 41. In this case, we opted for the use of combined pull headgear with a greater vertical component to correct the Class II by differential anterior displacement of the mandible (due to growth) associated with the use of Class III elastics to reposition the lower incisors. At the end of treatment we achieved the correction of dental and skeletal relationships (ANB = 3º) at the expense of restricting the anteroposterior and vertical maxillary growth, in addition to the distal movement of the upper teeth and adequate anterior mandibular growth response. As a result of a better dental and skeletal positioning the patient developed a passive lip seal.
- 44. In adult patients, who obviously do not exhibit sufficient growth to correct skeletal problems a viable alternative would be the extraction of teeth to solve occlusal disorders, which would mask the skeletal problem, or otherwise perform orthognathic surgery. When a first treatment was performed in which growth was not been used for malocclusion correction and dental extractions were made, one approach to be discussed is the orthodontic treatment combined with orthognathic surgery.
- 45. case 5 a 26 year-old female patient with a convex profile, skeletal Class II, Angle Class II, division 2 malocclusion, zero lower TAD, 4 mm overjet, 40% overbite, excessive exposure of maxillary incisors, increased lower facial third, teeth 35 and 45 congenitally missing, teeth 14 and 24 extracted in a previous treatment. The patient’s main complaint regarded her dental and facial aesthetics. The two possible solutions to this case would be either to distalize some upper teeth to achieve dental correction only, which would probably worsen her facial aesthetics, or to eliminate any dental tipping used as compensation, subsequently performing orthognathic surgery with maxillary impaction and mandibular advancement.
- 48. Based on the patient’s complaint, we opted for the surgical treatment with leveling and alignment, elimination of dental compensations, extraction of teeth 18, 38 and 48, impaction of the maxilla, mandibular advancement and genioplasty. The results included harmonic occlusal relationships with adequate positioning of the teeth in their bony bases and correction of skeletal disharmonies.
- 51. DENTAL ASYMMETRY The assessment of dental and facial aesthetic is an important factor in the process of orthodontic diagnosis and treatment planning. One of the biggest challenges in these two tasks is the correct positioning of the upper and lower dental midlines relative to each other and to the face. According to Strang, the harmonic positioning of the midlines relative to each other and to the face is what characterizes normal occlusion, and any variation in this combination is indicative of improper relationship between the teeth or dental arches. This requires a careful diagnosis because properly assessing the causes behind midline shifts allows professionals to use unique mechanics and asymmetric extractions.
- 52. According to Lewis, several methods are proposed for diagnosing midline shifts. Chiche and Pinault reported that assessment should be based on three factors: the center of the upper lip, the position of the papilla and central incisor tipping. The diagnosis can also be accomplished using well-molded plaster casts, marking two or three points in the posterior-most region of the mid- palatal raphe and positioning the reticulate plate over these points.
- 53. Patients presenting with severe dental midline deviation relative to the face (especially in the lower arch) require tooth extractions. Small asymmetries can be corrected with intermaxillary elastics or mini- implants (in some cases, unilateral mechanics), asymmetric extractions, stripping, and in a few situations, orthodontists will have to settle for completing orthodontic treatment with a little midline deviation. The lack of coincidence between the dental and facial midlines is more noticeable in the upper arch and is unsightly. This deviation can be the main reason for many patients to seek orthodontic treatment.
- 54. Case 6 an 18 year-old female patient, who had a skeletal Class II malocclusion (ANB = 8º), upper and lower incisors well positioned (1.SN = 104º and IMPA = 92º), straight facial profile (UL-S = 2 mm and LL-S = 1 mm). Regarding the dental relationship, the case presented with a large lower asymmetry due to a prior treatment which had extracted tooth 44 only, a - 3 mm lower TAD, 2 mm overjet, 50% overbite.
- 57. Based on these diagnostic data, we opted for extracting tooth 34 to correct the lower asymmetry. Although the extraction of this tooth alone would correct the lower asymmetry it would also cause the left canine relationship to go into Class II. To avoid this undesired effect, the upper second premolars had to be extracted. The extraction of tooth 25 enabled the maintenance of normal occlusal relationship in the left canines, and of tooth 15 maintained the upper arch symmetry.
- 58. Initially, a question may still remain unanswered when evaluating this clinical case. How can we prevent dental extractions from worsening the profile of this patient, which looked so appropriate at the start of treatment? To avoid worsening the profile, we used mechanical resistant torque resources, labial crown in the lower incisors and omega loops that were well adjusted to the second molar tubes so as to avoid the lingual repositioning of the lower incisors, as well as mini-implant support to lose anchorage in the lower right hemi-arch. By following the procedures described above we were able to complete treatment having achieved the correction of the Class II malocclusion without compromising the facial profile. It should be emphasized that after treatment completion, the patient underwent a rhinoplasty to further improve her profile aesthetics.
- 61. FACIAL PATTERN Patients with different facial patterns require different mechanics, and responses to orthodontic treatment are not similar. Dolichofacial patients feature increased facial height relative to the width, exhibiting a long, narrow and protruding face. Furthermore, they have hypotonic facial muscles in the vertical direction and can therefore present with anterior open bite. These patients normally suffer from greater anchorage loss, which helps in closing spaces. Greater control should be exercised, however, in order to avoid excessive anchorage loss and the consequent lack of space to ensure the planned correction. Extrusive mechanics should be avoided, as well as distal tooth movement.
- 62. Brachyfacial patients’ facial width is greater than their facial height, displaying a broad, short and globular face. These patients are not as prone to anchorage loss due to certain muscle characteristics (hypertonic masticatory muscles) that hinder tooth movement. Many patients have brachycephalic overbite. Since in these cases tooth extractions tend to worsen the vertical overlap, adequate mechanical control is required. Although normally dolichocephalics experience greater anchorage loss than brachycephalics, this is not always the case. Therefore, extra care must be taken during space closure.
- 63. The literature suggests the removal of posterior permanent teeth first, with subsequent loss of anchorage, to correct anterior open bite by means of counterclockwise rotation of the mandible. Moreover, some authors question this association between growth reduction and vertical extraction. However, clinical experience shows that moving the posterior teeth distally tends to cause the opening of the mandibular plane, especially in patients who have already gone through the growth spurt or those who exhibit an unfavorable growth pattern (predominantly vertical), which leads to the need for more extractions. On the other hand, extractions performed in association with vertical control (use of vertical chin cup, high-pull headgear, mini-implants, non-use of extrusive mechanics) may result in the closure of the mandibular plane and/or control of vertical facial growth, with decreased lower facial third, improving lip seal.
- 64. Case 7 a patient with a vertical facial pattern. The clinical examination revealed anterior and posterior open bite. According to the treatment plan there was an indication for the extraction of upper second molars, preserving teeth 18 and 28, besides the placement of orthodontic mini-implants to intrude the maxillary molars, moving them distally while maintaining anchorage during retraction. Mandibular crowding was resolved by stripping, especially incisors with a triangular shape and with the presence of black spaces, when aligned.
- 66. The results achieved in this case were the correction of the Class II dental relationship with bite closure by intrusion of the upper molars. The superimposition shows the total intrusion of the upper molars, a decreased mandibular plane as a result of the counterclockwise rotation of the mandible, and the consequent open bite closure.
- 69. PATHOLOGIES Some pathologies play a key role in defining orthodontic treatment planning. Patients can have half-formed teeth, ageneses, ectopias, abnormal shapes or even carious processes, and endodontic lesions that indicate tooth extraction. During diagnosis these conditions should be considered as they may change—in certain situations—the choice of the tooth or teeth to be extracted.
- 70. In patients with an indication for premolar extraction due to a sharp negative model discrepancy, but with extensive decay in the first permanent molars, these teeth are a viable extraction alternative for the premolars. In asymmetric malocclusions, where only one tooth must be extracted, if the patient happens to have an anomalous tooth, this tooth should be selected for extraction. Many other pathological conditions such as cysts, abnormal roots and periodontal problems indicate the extraction of teeth. Thus, the different pathologies greatly contribute to orthodontic treatments involving extraction.
- 71. case 8 A female 10 year-old patient. She was in the mixed dentition phase and had an Angle Class I malocclusion, 3 mm anterior open bite, mouth breathing, upper midline shifted due to a missing tooth (21) and skeletal Class II relationship. The maxilla was slightly contracted with no crossbite and she had a 6 mm lower arch model discrepancy. An analysis of the lateral radiograph showed skeletal Class II (ANB = 6º), vertical facial growth pattern (SNGoGn = 42º and Y axis-SN = 74º), upper incisors retroclined (1. NA = 16º) and linguoversion (1-NA = 3 mm) and lower incisors protruding and in labioversion (1. NB = 29º and 1-NB = 5 mm), although the latter were well established in the mandible (IMPA = 89°). The profile was straight (S-UL = +1 / S-LL = +1).
- 72. The panoramic radiograph disclosed an inverted (intraosseous) position of tooth 21 with an irregularity in the root portion suggestive of laceration. The lateral cephalometric radiograph showed an angle of approximately 90º between the root and crown of the central incisor. The patient had a prior habit of thumb sucking, which accounted for the anterior open bite and was maintained thereafter by the anterior posture of the tongue.
- 75. The excessive vertical pattern and negative TAD were regarded as the decisive factors to determine the extraction of the four premolars. However, the pathology (ectopia and laceration) of tooth 21 determined the need for its extraction instead of tooth 24. We carried out the transposition of tooth 23 to the location of tooth 21.Thus, the case was treated with the extraction of teeth 14, 21, 34 and 44. At the end of treatment, the patient’s vertical pattern was maintained (SNGoGn = 40º / YSn axis = 73°) thanks to the dental extractions and use of a combined extraoral traction headgear, and minimizing—with this mechanics— the extrusive vector. The headgear improved the anteroposterior relationship of the bony bases (ANB = 2º), changing the case from a skeletal Class II to a Class I relationship.
- 78. CONCLUSIONS Any decision regarding the need for extraction of teeth during orthodontic therapy is not only dependent on the presence or absence of space in the dental arches. Other issues should be evaluated in order to achieve proper malocclusion correction, maintenance or improvement of facial aesthetics and result stability.
- 80. borderline cases A case is borderline when extraction of permanent teeth is required to reach a stable and functional occlusion, but when the patient has good facial esthetics that could be disturbed by extractions. Borderline case may also be defined as the case caught in between the conflict of extraction and non-extraction. “Empirical evidence of uncertainty exists with these patients. Borderline cases may also have an absence of dental or craniofacial anomalies, permanent dentition, healthy periodontium and normal anteroposterior relationship between maxilla and mandible.
- 81. Factors affecting extraction decision
- 82. Dental variables
- 83. Tooth-size arch length deficiency (TSALD) TSALD is the most common form of malocclusion treated by orthodontists. Indices which may be used to find out TSALD. Carey has set 2.5-5 mm TASLD as a borderline case.McNamara set arbitrary borderlines of 3-6 mm.Gust, concluded “amount of maxillary arch length discrepancy may range from 6 to 8-11 mm for borderline cases. Roughly 1 mm of crowding in either arch to constitute definitive nonextraction, while definitive extraction therapy in the maxillary and mandibular arches was 5.8 and 7.3 mm, respectively.
- 84. Curve of Spee One popular rule of thumb for estimating the resulting loss of arch circumference is that 1 mm of arch circumference is needed for each millimeter of curve of Spee depth present. Recent studies conclude the real effect to be closer to 1:3; for every 3 mm of curve leveled, arch circumference increases 1 mm. According to Woods,the amount needed is variable depending on the type of mechanics used. The deeper the curve of Spee, the greater the need for extraction. Roth considered 3-6 mm of curve of Spee mild (1.5-3.0 per side), and Baldridge added that greater than 6 mm is severe.
- 85. Bolton’s discrepancy A tooth-size discrepancy (TSD) is defined as a disproportion among the sizes of individual teeth. In order to achieve a good occlusion with the correct overbite and overjet, the maxillary and mandibular teeth must be proportional in size. Bolton (1958) noted a TSD of up-to 4 mm to be a limit of the anterior reduction. Extraction may be necessary to resolve a discrepancy greater than this.
- 86. Peck and peck analysis Peck and peck analysis takes into account the labiolingual width of the tooth rather than mesiodistal (MD) width as in Bolton’s analysis. Peck and peck analysis is calculated as MD length of mandibular incisor divided by its labiolingual width. MD and faciolingual (FL) index values for mandibular central incisor is 88- 92 and for mandibular lateral incisors is 90-95. Patients with MD/FL indices above the desired ranges may be candidates for the reproximation. Index values lower than normal range warrant extractions.
- 87. Irregularity index Little developed the irregularity index and mandibular anterior irregularity by adding the linear distances between the five adjacent anterior contact points. With perfectly aligned incisors, the score is zero. Little noted a score >6.5 mm indicates severe irregularity and, thus, the greater likelihood for extraction.
- 89. Skeletal variables Vertical dimension is the most important to the clinician. Two important angles for the assessment of vertical dimension are Sella- Nasion and mandibular planes (SN-MP) angle and FMA angle. SN-MP angle formed at the intersection of the SN-MP with the average value of 33° for balanced vertical facial types, with a range of 31-34°. The normal value for the FMA is in the range of 20-30°. Values above these normal ranges are associated with skeletal open bite, whereas values below are typically associated with skeletal deep bite.
- 90. SN-MP Angle
- 91. FMA angle
- 92. Skeletal variables Regardless of the clinician’s form of vertical assessment, there is agreement among these measurements regarding extraction and non- extraction therapy. Treatment geared toward achieving facial balance is more likely to extract in skeletal open bite and not extract in cases with skeletal deep bite.
- 93. Dental variables: Incisor mandibular plane angle (IMPA) Charles tweed noted a need for “upright” and “vertical” lower incisors to create facial balance and harmony. He proposed IMPA to be 90° ± 3° in normal, balanced faces. According to tweed, this value can range between 85° and 95°, and vary according to ethnicity. Values above this range are indicative of extraction to improve functional and esthetic imbalance.
- 95. Dental variables: A to Pogonion (A-Pog) line McNamara found the proper position of the mandibular incisor to be 1-3 mm anterior to a line from point A-Pog in a well-balanced face, regardless of age.
- 96. Dental variables: Maxillary and mandibular incisor from Nasion to A and B point respectively Steiner set the ideal positions of the maxillary and mandibular incisors to be 4 mm anterior to the lines connecting Nasion and point A, and Nasion and point B, respectively. The maxillary and mandibular incisors should form angles of 22 and 25° to their respective diagnostic lines. Extraction becomes more likely as incisor positions and angles exceed these values horizontal planes
- 97. Soft tissue PLEASING SOFT TISSUE PROFILE SHOULD BE THE MAIN FOCUS OF ORTHODONTIC DIAGNOSIS AND TREATMENT PLANNING.
- 98. Position of upper and lower lip A borderline case with pre-treatment lip protrusion may be better served with extraction. Similarly, a more retrusive profile may be improved without removing teeth. Ricketts first identified the esthetic plane, relating lip position to a line from the nasal tip to soft tissue Pogonion. In the aging face, lips become relatively more retruded, creating a natural difference in proper lip positions between different age groups. In the adolescent, the lower lip is about 2 mm behind the esthetic plane, or E line, with a standard deviation of 3 mm. The adult lower lip is ideal about 4 mm behind the E line with a similar standard deviation.
- 99. Burstone found it advantageous to consider lip position relative to a line connecting subnasale and soft tissue pogonion because it is based on a “plane of minimal variation in the face. The author noted the nose is an area of great variation, “approximately twice” the standard deviation as lower lip protrusion (2.8 vs. 1.6). Since lip protrusion can disrupt an otherwise pleasing face, extraction may be necessary the further a patient is from the ideal.
- 100. For each 1 mm of retraction of the upper incisor, the upper lip retracts 0.75 mm. Talass et al. found lower values for this ratio which is 1/0.64.On the other hand, lower lip retracts by 0.6 mm for every 1 mm of lower incisor retraction. Thus, retraction of anterior teeth for space closure makes the profile more concave.
- 101. Naso labial angle There is a great deal of variation in the literature as to what constitutes the ideal value. According to Burstone’s evaluation of lip relation, a preferable nasolabial angle value is 78. More recent studies find more suitable values in the range of 90-115°. Extraction of four bicuspids was noted to increase the nasolabial angle 5.2° by Drobocky and Smith. Therefore, extraction of teeth in a borderline patient with a nasolabial angle greater than the normative values should be avoided. 3.8° ± 8°.
- 102. Lip prominence Holdaway’s soft tissue analysis includes linear measurements to assess upper lip morphology and strain. The thickness of upper lip should be measured in two different areas: 3 mm below skeletal point A, and from the vermillion border to the labial surface of the maxillary central incisors. In normal patients, these two measurements should be approximately the same (±1 mm). If the vermillion border is thinner than the upper lip near point A, the lip are considered strained. If the upper lip is thinner than the vermillion border, the lips are considered flaccid.
- 103. In borderline patients with strained lips, the incisors can be retracted without altering the soft tissue profile because the lip needs to reach normal form and thickness before retraction. In such patients, extraction is indicated. On the other hand, the lips would immediately follow tooth movement in borderline patients, with normal lips. According to Arnett and Bergman, orthodontists should avoid extraction in patients with flaccid lips due to the lack of labial support and the potential for esthetic problems.
- 104. Midline deviation Proper assessment of facial, skeletal, and dental symmetry is essential in orthodontic diagnosis. It is important to determine which dental segment deviation is responsible for the shift. Evaluation of the dental midline should be assessed with respect to the face, and treatment planning should be done which is compatible with the situation. A deviation of the dental midline(s) may indicate a skeletal asymmetry and require surgery for correction. Severe dental midline deviation relative to the face (especially in the lower arch) requires tooth extractions.
- 105. Minor shift in midline can be corrected with the use of intermaxillary elastics or mini-implants (in some cases, unilateral mechanics), asymmetric extractions, stripping. In a few situations, orthodontists will have to settle for completing orthodontic treatment with a little midline deviation. Dental and facial midlines deviations are more noticeable in the maxillary arch and appear unsightly. Midline deviation can be the main reason for patients to seek orthodontic treatment. The literature provides little data on the quantity of deviation relating to the borderline of extraction.
- 106. Growth status It is very important to keep in mind the facial growth status of the young patient; particularly those with malocclusions of skeletal origin. Growth of the soft and hard tissues has a significant influence on the facial results of orthodontic treatment. With age due to growth of soft tissues of the face, the profile of an individual becomes more convex. Gross facial imbalance can be caused by additional growth of the nose after the appliance removal. Extractions should be avoided in growing patients. These cases show favorable results with growth response (growth redirection). If further growth is unlikely to alter facial profile, extraction decision will be safer.
- 107. Conclusion A Borderline case may be treated by either extraction or non-extraction methods. Dichotomy exists with these cases. Further, borderline cases may also have absence of dental or craniofacial anomalies, permanent dentition, healthy periodontium and normal anteroposteriorly relationship between maxilla and mandible. Therefore; precise treatment planning is a must for borderline cases to provide best possible esthetics and stability of the results to the individual.
- 108. References Extraction in orthodontics, Glasgow notes, Mohammed Almuzian, 1-1-2013. A dilemma in orthodontics: Extractions in borderline cases Sushma Dhiman, Sandhya Maheshwari Department of Orthodontics and Dental Anatomy, Aligarh Muslim University, Aligarh, Uttar Pradesh, India, Journal of Advanced Clinical & Research Insights ● Vol. 2:1 ● Jan-Feb 2015 Tooth extraction in orthodontics: an evaluation of diagnostic elements Antônio Carlos de Oliveira Ruellas*, Ricardo Martins de Oliveira Ruellas**, Fábio Lourenço Romano***, Matheus Melo Pithon**, Rogério Lacerda dos Santos* (all clinical cases are of curticy of this article).
- 109. Thank you