|Year : 2015 | Volume
| Issue : 4 | Page : 286-290
Lower incisor extraction: Can it be justified? A report of two cases
Kalyani Mallavarapu1, Revathi Peddu1, Syagamreddy Rama Koteswara Reddy2, Sai Prakash Adusumilli2
1 Department of Orthodontics, Sibar Institute of Dental Sciences, Guntur, Andhra Pradesh, India
2 Department of Orthodontics, Sibar Dental College, Guntur, Andhra Pradesh, India
|Date of Web Publication||14-Dec-2015|
Department of Orthodontics, Sibar Institute of Dental Sciences, Guntur - 522 509, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
Extraction versus nonextraction debate is still continuing since 1900s. Some cases demand extraction of premolars, but the decision making is difficult in the border line cases with good facial esthetics. Lower incisor extraction becomes a therapeutic alternative to premolar extractions in lower anterior crowding cases with good facial esthetics and well occluded posterior teeth. Diagnostic setup reveals the posttreatment occlusal possibilities and hence the most important step in the diagnosis and treatment planning of these cases. Lower incisor extraction decision would be a better option in cases with anterior Bolton's discrepancy. Two cases treated with single lower incisor extraction, indications, contraindications and measures to attain posttreatment stability are discussed in this presentation.
Keywords: Bolton′s discrepancy, diagnostic setup, lower incisor extraction, posttreatment stability
|How to cite this article:|
Mallavarapu K, Peddu R, Reddy SK, Adusumilli SP. Lower incisor extraction: Can it be justified? A report of two cases. J NTR Univ Health Sci 2015;4:286-90
|How to cite this URL:|
Mallavarapu K, Peddu R, Reddy SK, Adusumilli SP. Lower incisor extraction: Can it be justified? A report of two cases. J NTR Univ Health Sci [serial online] 2015 [cited 2020 Jan 27];4:286-90. Available from: http://www.jdrntruhs.org/text.asp?2015/4/4/286/171766
| Introduction|| |
Permanent first premolars are routinely extracted to alleviate anterior and/or posterior crowding due to their location in the center of each half of the arch.  As pointed out by Kokich and Shapiro  extraction of a lower incisor in certain cases constitutes a therapeutic alternative and allows the orthodontist to improve occlusion and dental esthetics with a minimum of orthodontic treatment. However, a diagnostic set-up is required to predetermine the precise occlusal possibilities. 
Lower incisors with loss of gingival tissue, normal maxillary dentition with good buccal interdigitation and severe lower anterior crowding, lower anterior Bolton's excess of >4 mm, adult cases with mild to moderate Class III malocclusion, ectopically erupted or supernumerary lower incisor, missing or peg shaped upper lateral incisors or macrodontia of lower incisors are good indicators for lower incisor extraction. ,,,
Lower incisor extraction should be avoided in cases with an excessive overbite and over jet, bimaxillary crowding cases with no Bolton's discrepancy in the incisor area and cases having large maxillary incisors and small mandibular incisors. 
Whether to extract a central or lateral incisor depends on the type of malocclusion, amount of anterior tooth size discrepancy, arch length deficiency in the anterior region, health condition of the teeth and supporting tissues. 
Two cases treated with single lower incisor extraction are documented in this presentation.
| Case Reports|| |
A male patient aged 22 years reported for treatment with mesoprosopic facial pattern, mild convex profile, prominent nose, normal nasolabial angle, Angle's Class I molar and canine relationship, severe lower anterior crowding, 11 in cross bite with 41 and good posterior occlusion [Figure 1] and [Figure 2]. Panoramic radiograph showed presence of all the permanent teeth. Cephalometric analysis revealed skeletal Class I malocclusion, with normodivergent growth pattern, mild proclination of upper and lower incisors.
The treatment was aimed to correct the lower incisor crowding and cross bite, level, align and establish optimum over jet and overbite while maintaining a Class I molar and canine relationship.
Treatment plan and mechanics
Preadjusted edge-wise appliance of MBT prescription (0.022" × 0.028" slot) was set up and extraction of lower right central incisor was carried out and inter-proximal reduction was done in the upper anterior region after making a diagnostic setup [Figure 3]. Arch wire sequence was 0.014" nickel titanium (NiTi), 0.017" × 0.025" NiTi and 0.019" × 0.025" stainless steel (SS) followed by 0.021" × 0.025" SS. Ideal torque, optimum interincisal angle and root parallelism were achieved at the end of the treatment. The retention plan consisted of an upper Hawley's retainer and a fixed lingual retainer on the lower anteriors.
At the end of treatment lower incisor crowding was relieved with improvement in facial esthetics, maintaining Class I molar and canine relationship with good posterior occlusion, normal over jet and overbite [Figure 4] and [Figure 5]. Superimposition of pre and postcephalometric tracings revealed slight proclination of upper and lower anteriors [Figure 6] and [Table 1].
|Figure 6: Superimposition of pre and posttreatment cephalograms|
of case 1
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|Table 1: Pretreatment and Posttreatment Cephalometric Measurements For Case 1|
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A 14-year-old boy presented with the chief complaint of irregular lower front teeth. Clinical examination revealed competent lips, a straight profile with molar and canine in Class I relationship. Model analysis revealed crowding of 7 mm in the lower arch with Bolton's discrepancy of 4 mm excess in the lower anteriors. The patient had 80% overbite and 3 mm over jet, and lower midline shifted 2 mm to the right [Figure 7] and [Figure 8].
Relieving of upper and lower anterior crowding, maintenance of Class I molar and canine relationship and to achieve the ideal over jet/overbite with good profile.
Treatment plan and mechanics
Lower incisor extraction was planned because of a good profile, minimal space requirement and Bolton's discrepancy of 4 mm anterior excess in the lower arch. Preadjusted edge-wise appliance of MBT prescription (0.022" × 0.028" slot) was setup and the lower central incisor was extracted. Wire sequence was 0.014" NiTi, 0.018" SS, 0.019" × 0.025" NiTi, 0.019" × 0.025"SS, followed by 0.021" × 0.025" SS in the upper and lower arches for torque expression. Settling of occlusion was achieved with 0.016" SS and elastics.
Posttreatment facial photographs showed little change in facial profile. The Class I molar and canine relationship was maintained, ideal over jet and overbite were achieved with good alignment in both upper and lower arches [Figure 9] and [Figure 10]. An increase in the inclination of upper and lower anteriors can be observed from pre and postcephalometric measurements [Figure 11] and [Table 2]. Superimposition of pre and postcephalometric tracings revealed mild nasal growth and improvement in the chin position.
|Figure 11: Superimposition of pre and posttreatment cephalograms|
of case 2
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|Table 2: Pretreatment and Posttreatment Cephalometric Measurements For Case 2|
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| Discussion|| |
Extraction of lower incisor would be a viable alternative in cases with good facial balance and posterior occlusion where routine premolar extraction or nonextraction treatment might affect the esthetics. Factors to consider before proceeding for lower incisor extraction were lower anterior crowding, anterior Bolton's discrepancy, gingival health of the lower anteriors, shape of the incisors, proximal enamel thickness of the upper anteriors etc., diagnostic setup form an important diagnostic tool. Maxillary anterior Bolton's excess that results after the lower incisor extraction can be managed by the inter-proximal reduction of upper anteriors considering maxillary crown structure, inter-proximal enamel thickness, root proximity of upper anteriors.
Black triangles in the closed extraction site, in some cases can be addressed by over paralleling the roots adjacent to the extraction site, by proximal enamel reduction to diminish the bell-shaped contours of the teeth adjacent to the missing tooth, or by building up the proximal surfaces with composite. 
The extraction of lower incisor reduces the dental crowding without increasing the intercanine width and improves lower anterior root parallelism, reduce root proximity and the results are more stable as compared to premolar extraction cases in the absence of permanent retention due to the maintenance of teeth in their original position, where muscular pressures are less likely to introduce instability and use most of the extraction space to correct the anterior crowding. 
| Conclusion|| |
In carefully selected cases successful treatment results can be achieved with lower incisor extraction with simple mechanics in shortest treatment time and is a viable alternative for routine premolar extractions.
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.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11]
[Table 1], [Table 2]