|Year : 2017 | Volume
| Issue : 5 | Page : 27-31
Role of genioplasties in various chin deformities
Amit Garg1, Nisha Garg2, Gurinder Bir Singh Thind3, Amita Kashyap4, Akash Dupper5, SC Anand6
1 Department of Oral and Maxillofacial Surgery, Rayat Bahra Dental College and Hospital, Mohali, Punjab, India
2 Department of Conservative Dentistry and Endodontics, Bhojia Dental College and Hospital, Baddi, Solan, Himachal Pradesh, India
3 Department of Oral and Maxillofacial Surgery, Sri Sukhmani Dental College and Hospital, Dera Bassi,Punjab, India
4 Consultant at S.S.S.M Dental Clinic, Mohali, Punjab, India
5 Department of Conservative Dentistry and Endodontics, S.S D C, Dera Bassi, Mohali, Punjab, India
6 Department of Oral and Maxillofacial Surgery, Government Dental College, Rohtak, Haryana, India
|Date of Web Publication||15-Sep-2017|
House No. 2347, Sector 23 C, Chandigarh
Source of Support: None, Conflict of Interest: None
Aim and Objectives: The goal of surgical-orthodontic treatment of chin deformities is to achieve maximum function, esthetics, and stability. The objective of our study is to evaluate the role of genioplasties in various chin deformities. Materials and Methods: Twelve adult patients who manifested various types of chin deformities were treated. In eight patients, advanced genioplasty alone or in combination with other surgical procedures such as premaxillary osteotomy, gap arthroplasty, bilateral vertical ramus osteotomy, and advancing and sliding genioplasty was performed. Four patients were treated by reduction genioplasty alone or in combination with vertical ramus osteotomy. Results: Results were more predictable and stable in case of chin advancement procedures as compared to reduction genioplasty. Conclusion: It was observed that the chin should not be completely denuded, muscular attachment on the lower part of the chin should always be maintained, if possible.
Keywords: Advanced genioplasty, chin deformities, genioplasty, reduction genioplasty
|How to cite this article:|
Garg A, Garg N, Thind GB, Kashyap A, Dupper A, Anand S C. Role of genioplasties in various chin deformities. Indian J Dent Sci 2017;9, Suppl S1:27-31
|How to cite this URL:|
Garg A, Garg N, Thind GB, Kashyap A, Dupper A, Anand S C. Role of genioplasties in various chin deformities. Indian J Dent Sci [serial online] 2017 [cited 2018 Oct 15];9, Suppl S1:27-31. Available from: http://www.ijds.in/text.asp?2017/9/5/27/214933
| Introduction|| |
Role of chin in facial profile is most obvious and an outstanding feature in facial appearance. Its importance has been recognized since antiquity, and there have been various alloplastic ivory and bovine bones to augment the chin, thus obtaining contour of the chin in the most reliable manner.
Advancement of chin by means of horizontal osteotomy of mandibular symphysis can be used to improve the facial profile. This procedure can be undertaken alone or in conjunction with other surgical procedures. This study has been undertaken to analyze and correct various deformities of chin surgically with emphasis on genioplasty.
| Materials and Methods|| |
A sample of 12 participants were selected for this study from a pool of patients attending the Outpatient Department of Oral and maxillofacial surgery and Department of Orthodontics, Government Dental College, Rohtak. Patients were divided into Groups A and B. In Group A, eight cases were selected, in which advanced genioplasty was done alone or in combination with other surgical procedures. Out of the eight cases, advancing genioplasty was done alone in five patients; advancing genioplasty and premaxillary osteotomy were done in one patient; gap arthroplasty, bilateral vertical ramus osteotomy, advancing and sliding genioplasty were done in one patient; and gap athroplasty and advancing and sliding genioplasty were done in the remaining one patient.
In Group B, three patients were treated by reduction genioplasty alone and one patient underwent reduction genioplasty in combination with vertical ramus osteotomy.
Diagnosis and treatment planning for all the patients were made on the basis of criteria used such as chief complaint, family history, clinical examination, and cephalometric tracings.
Cephalometry was employed to record hard and soft tissues in natural head position. Macksman II Model 2431-4221 (SS White) was used for recording cephalogram. To eliminate errors in landmark identification and measurements, all films were retraced and remeasured twice and the mean of two readings was taken. Preoperative cephalogram was taken 1 week before the surgery and postoperative cephalogram was taken 3 months after the surgery. Photographs were taken before, during, and after surgical procedure.
Lateral cephalogram was taken preoperatively, postoperatively, and during follow-up to assess the soft- and hard-tissue changes.
Nine patients were operated under general anesthesia and three under local anesthesia. Patients were instructed to do mouth rinse with 0.2% chlorhexidine thrice daily 2 days before the surgery. Prophylactic antibiotics and hydrocortisone were given 1 h before the surgical procedure. Preanesthetic medications were given as advised by an anesthetist.
Once the anesthesia was established, using B.P. blade no. 15, incision was given in the lower lip, 15–20 mm from the depth of vestibule in the midline when lip was retracted. Incision was carried laterally toward cuspid area of both sides. Mucoperiosteal flap was reflected to expose inferior border of the mandible and symphysis. Dissection was then extended posteriorly, and soft-tissue sleeves on mental nerves were gently dissected to minimize the retraction tension on nerve.
Bony cut procedures
It was done to increase chin projection, alter lower third facial height, and increase chin projection.
- In this, midline was marked on the chin and cut was given in such a way that the maximum amount of bone could be advanced without injuring cuspid apices or mental nerve
- Horizontal osteotomy was planned 4–5 mm below the apices of cuspids anteriorly and 3–4 mm below the level of mental foramen. Bony cut was made with tapering fissure bur and then a reciprocating saw was placed into this marking and carried out till the inner cortex. The bone was cut completely by osteotomy to mobilize the segment
- Once the segment was mobilized, any lingual cortical irregularities were removed which might prevent sliding forward of the inferior segment
- For stabilization of the inferior segment, holes were made through lingual cortex of mobile segment and buccal cortex of stable superior segment in the midline and on each side. Wires were tightened to pull the mobilized portion of the chin to the desired position. In some cases, the lag or position screws and bent mini plates were used to fix the repositioned segment.
It was done to decrease the size of the chin vertically, anteroposteriorly, laterally, or in all directions. It was mainly indicated in Class III cases or in macrogenia.
- Midline of symphysis was marked to maintain symmetry and two vertical lines were marked just anterior to the mental foramen
- Two holes were made into each of these vertical reference lines and ostectomy lines were made with tapering flat fissure bur on both sides with small depth cuts in the bone
- A reciprocating saw was placed on the lower border of ostectomy line and completed up to the inner cortex. Bony cut was completed with osteotome to mobilize inferior segment. Similarly, the superior ostectomy was done. Intervening segments were removed and both segments were fixed with the lag or positional screws after repositioning.
It was indicated in patients with facial asymmetries in which chin symmetry cannot be corrected by repositioning of jaws.
- Midline of symphysis was marked and appropriate bone cut was made
- Segment was repositioned and stabilized with wires and lag screws to match the facial midline.
- Incision was closed in two to three layers with absorbable and nonabsorbable sutures ,
- A supportive chin dressing was applied to soft tissue, holding the lip to eliminate the dead space.
All patients were called for regular follow-up at a regular interval of 6 months. Clinical examination, radiographs, cephalometric tracings, and photographs were taken to assess the improvement.
| Results|| |
[Table 1],[Table 2],[Table 3],[Table 4],[Table 5],[Table 6] show presurgical, postsurgical, and follow-up measurements of hard and soft tissues in advancement and reduction genioplasty (Group A) along with their mean and median in three phases, i.e., P1 (presurgical), P2 (postsurgical), and P3 (follow-up) in the following way:
|Table 4: Soft tissue cephalometric analysis of reduction genioplasty (final results)|
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|Table 5: Advancement genioplasty: Comparison of horizontal changes in mandibular prognathism (pg and pg’)|
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|Table 6: Reduction genioplasty: Comparison of horizontal changes in mandibular prognathism (Pg and Pg’)|
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Prominence of chin
- N-Pg: Mean and median values of P1, P2, and P3 in advancement genioplasty were compared, the chin was moved in anterior direction by 3.5 mm and 2.7 mm.
- B-Pg: When difference between mean and median was calculated, increase in chin prominence was 1.5 mm.
- SND angle: This angular measurement from Steiner's analysis was used to assess the relation of mandibular base to the base of skull. When mean and median of SND angle were calculated, prominence of chin in relation to the base of the skull showed increase by 2°, suggesting forward position of chin along with prominence.
Position of mandible and chin
This can be interpreted by analyzing various cephalometric skeletal points and their relation to other points which are as follows:
- N-B: This linear measurement helps in the assessment of anteroposterior position of mandible and degree of mandibular horizontal dysplasia. When mean and median values of N-B measurement were analyzed, the result was insignificant
- Facial angle: This angular measurement is used to assess the degree of retrusion or protrusion of the lower jaw. When mean and median values of facial angle were compared, forward positioning of the lower jaw was justified
- Y-axis: This angular measurement indicates the degree of downward or forward position of chin in relation to the upper face. When mean and median values of Y-axis were compared, there was a difference of 5° which confirms forward positioning of chin on advancement genioplasty.
Length of mandible
- Go-Pg: When mean and median values were compared, there was a definite increase in the length of mandible by 2 mm.
- N-A-Pg: When mean and median values were compared, it showed decrease in this angular measurement, suggesting a less convex profile.
| Discussion|| |
The present study analyzed 12 cases which required different genioplasty procedures and outcome of hard- and soft-tissue changes following procedures. Out of the 12 cases, eight were operated for advancement genioplasty (Group A) and four for reduction genioplasty (Group B) alone or in combination with other procedures.
Cephalometric analysis for hard- and soft-tissue advancement genioplasty was carried out using Cogs, Downs analysis, Steiner's analysis, and Holdaway analysis,,, but cephalometric points pertaining only to chin region from these analysis were utilized. While in reduction genioplasty, cephalometric analysis was carried out using some of the cephalometric points from Cogs, Downs, Steiner, McNamara, and Ricketts  analysis.
In our study, 12 cases were treated, of which nine were females and three were males. Parula and Oikarinen  found that women are more concerned about cosmetics and thus seek help for improving their profile when compared to men.
In reduction genioplasty, chin was not completely degloved as pointed by Epker and Wolford,, reduction should not be done on the lower part of the chin as it can lead to double chin. In our study, prominence of chin, position of mandible and chin, length of mandible, facial convexity, and relation of central incisor to N-B were taken in advancing genioplasty and compared with the findings of Burstone, Legan, Steiner, and Down's analysis.
Soft-tissue cephalometric analysis of advancement genioplasty was done using facial convexity, mandibular prognathism, mentolabial sulcus, vertical lip–chin ratio, vertical height ratio, and soft-tissue chin thickness. Findings were compared with the studies of Legan and Burstone, Holdway and Hambleton, and Hambleton,, all these favored the results of advancement genioplasty.
In reduction genioplasty, similar cephalometric points of soft tissue were analyzed and compared to that of Legan and Burstone, Steiner, Holdway and Hambleton, and Hambleton,, and the results were comparable to that of reduction genioplasty.
In case of horizontal sliding osteotomy, results were more stable and predictable. Bell and Dann found a consistent relationship between bone and soft-tissue change of 1:0.6, thus soft-tissue advancement was 60% of the bony advancement. This became more clear in the present study because soft-tissue detachment should be minimal during genioplasty procedure. On comparing the mean and median values, soft tissue advanced by 80%–90% when compared to bony tissue. Observations were confirmed by McDonnell et al. who found soft-tissue advancement of 75% as compared to bony chin.
In our study regarding reduction genioplasty, soft tissue advanced by 1.5 (mean) and 0.9 (median) times of bony chin. Krekmanov and Kahnberg  found that prediction of soft-tissue movement in case of posterior repositioning of segment was difficult on reduction due to thickening of soft tissue. Thus, the result of soft-tissue advancement as compared to hard-tissue advancement was not as predictable and stable as in advancement genioplasty.
In our study, no postoperative infection was seen, but in one case, dehiscence of wound margin was found, which could be due to improper incision. To avoid dehiscence or tension of sutured mucosa, incision should be given along the lower border of the lip and deeper incision should be directed toward chin bone.
| Conclusion|| |
Orthognathic surgery is one of the highly specialized branches of oral and maxillofacial surgery. In cases where multiple deformities are present, genioplasty along with orthodontic procedures gives predictable results.
We found that results were more predictable and stable in case of chin advancement compared to reduction genioplasty. From biological aspect, it was emphasized that chin should not be completely denuded, as far as possible, muscular attachment on the lower part of chin should always be maintained.
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.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]