CLINICAL STUDY
Soft Tissue Response After Chin Advancement Using Two Different Genioplasty Techniques: A Preliminary Technical Comparative Study Sameh Ahemd Seifeldin, BDS, MSc,*† Maha Shawky, BDS, MSc,‡ and Saleem M. Hicham Nouman, BDS† Purpose: The aim of this study was to evaluate soft tissue response after chin advancement using 2 different genioplasty techniques. Methods: The study included 8 adult patients who were divided equally into 2 groups: group 1 was surgically treated by sliding genioplasty, and group 2 was surgically treated by chin shield genioplasty for the correction of retruded or deficient chin. Lateral cephalograms were taken twice: immediately preoperative and 6 months postoperative. Results: The mean (SD) change of soft tissue pogonion (Pg') was 4.7 (0.3) mm in group 1, whereas in group 2, the mean (SD) change of soft tissue pogonion (Pg’) was 6.2 (4.8) mm. The mean (SD) change in the labiomental depth in group 1 was 0.9 (0.3) mm, whereas in group 2, it was 0.2 (0.5) mm. So in group 2, chin shield genioplasty contributed to a less labiomental fold depth. The ratio of soft tissue response to bony movement in the sliding genioplasty technique was 1:0.83, whereas in the chin shield genioplasty technique, it was 1:0.99. Conclusions: In the chin shield genioplasty technique, the increase in labiomental fold depth was less than in the sliding genioplasty technique. Key Words: Sliding genioplasty, chin shield genioplasty, soft tissue change (J Craniofac Surg 2014;25: 1383–1388)
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he chin is a prominent facial feature that plays an important role in the overall facial appearance. The deficiency of chin is one of the deformities that cause facial disfigurement. Surgical correction of cosmetic deformities of the chin can be performed by either chin augmentation with an implant or by osteotomy and advancement of the bony mentum. Chin augmentation using alloplastic implants is an effective means of correcting an antero-posterior chin deficiency (microgenia). The chin is an important and often neglected feature
From the *King Saud University, Saudi Arabia; †Cairo University, Egypt; and ‡King Abdullaziz University, Jeddah, Saudi Arabia. Received October 24, 2013. Accepted for publication February 8, 2014. Address correspondence and reprint requests to Sameh Ahmed Seifeldin, BDs, Msc, PhD, King Saud University, B.O. 60169, Riyadh 11545, Saudi Arabia; E-mail: [email protected] No research center provided funding or budget for the research work, and all is done with the authors’ own expenses. The authors report no conflicts of interest. Copyright © 2014 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000000863
of facial balance. Correction of chin recession has always been difficult because of the bony substance in which to perform osteotomy is always insufficient. So, the surgical correction of these deformities is one of the most challenging and intriguing aspects of oral surgery. Genioplasty is a useful procedure in esthetic surgery and can be combined with other procedures to obtain an optimal esthetic outcome.1 It has been shown that the public places more emphasis on the lips than on other facial structures when evaluating facial esthetics. This might explain why the patient’s overall satisfaction when undergoing maxillofacial surgery is primarily driven by the final position of the soft tissues. On that basis, the effects of orthognathic surgery on the soft tissue profile, especially the lips, must be understood and predictable.2 Genioplasty has become a routine procedure in the correction of dentofacial deformities. In addition to allowing improvement of the profile, functional genioplasty makes it possible to obtain muscular equilibrium in the labiomental and even the nasolabial region of the face.2 The procedure of genioplasty can be performed as a sole procedure or in combination with other surgical procedures in the maxilla and/or the mandible.3–5 The genioplasty procedure is differentiated further and classified by variations in technique, the reciprocal movements of the mandible segments, and the final result desired.6–10 Concerning the different genioplasty techniques, Ward et al11 reported that, in the sliding genioplasty, the osteotomy segment slides anteriorly or posteriorly, and the vertical dimension of the lower third of the face is altered accordingly. However, in the jumping genioplasty, the caudal segment is moved anteriorly and placed in front of the mandible, almost like an implant. The lower soft tissue attachments of the segment should be preserved to avoid bone resorption. This nomenclature was used for the first time by Gilles and Millard12 who indicates the attempt to improve the sagittal projection of the chin and decrease the height of the lower facial third. In graft genioplasty or interpositional genioplasty, the advancement is achieved by the interpositioning of bone graft between the mandible segments to advance the chin as well as increase the lower facial height (sandwich horizontal osteotomy). On the other hand, wedge genioplasty is involving the removal of a segment of the bone. Two horizontal osteotomies parallel to each other and to the occlusal plane are performed, and after the caudal cut is made, the segment between the osteotomies is resected.11 The stepladder/two-tiered genioplasty is used for important sagittal advancement without significant modification of the height of the lower facial third. Two osteotomies are performed, and the lower segment is advanced sagittally over an already-advanced proximal segment. In the centering genioplasty, vertical and horizontal asymmetries can be corrected. Depending on the asymmetry, a wedge of bone can be resected on the longer side and, if needed, mirror imaged to lengthen the contralateral deficient side.11
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Complications of genioplasty include mental nerve affection and loss of tooth vitality,13 change of lower labial sulcus depth, wound scaring,14,15 apical root resorption, loss of dental vitality, and periodontal pockets, which could be reduced by the use of piezoelectric cut.16,17 Neuroparaxia and neurotmesis of the nerve,18 “witch’s chin” deformity or lip incompetence, and drooling are common complications due to failure to reapproximate the mentalis muscle at the time of wound closure.19,20 Added to the mentalis muscle is the dysfunction manifested by an unsightly bulge of mental skin. Fortunately, this complication seems to be very rare.21 The soft tissue profile has emerged as perhaps the most important consideration for planning surgery and assessing treatment outcomes.22 This may be possibly because of the nonlinear relationship between horizontal hard tissue and soft tissue changes. Another possibility is that vertical movements influence the soft tissue movement of the chin. The relationship between the hard tissue and the soft tissue changes may be more complex than described earlier because soft tissue morphology, thickness, posture, and tonicity vary from person to person. The final soft tissue appearance may be dependent on the type of surgical technique used and on complications (such as scarring) that may arise from the surgical procedure. The accuracy of any prediction, however achieved, should be dependent on knowledge of the behavior of soft tissues.23 It has been found that the results of soft tissue changes in advancement genioplasty may be affected by the direction and magnitude of the genial segment movement and the design of the mucosal and osseous incisions.24 Presurgical predictions are important tools to demonstrate possible postsurgical results; those serve as an instrument for patient communication and provide a goal for operative treatment planning.25
PATIENTS AND METHODS This study was conducted on 8 adult patients. All patients were selected on the basis that their main problem was a deficient chin or retruded chin that required surgical correction by advancement genioplasty. The patients were divided into 2 equal groups: group 1 was treated by sliding genioplasty, whereas group 2 was treated by chin shield osteotomy genioplasty. For each, the following data were recorded: medical history, clinical examination, photographs, and radiographs including panorex view and lateral cephalometry. Clinical examination of oral structures was undertaken in a systematic fashion as follows: - the lips, cheeks, tongue, chin, and palate were examined; - competence, texture, thickness, and behavior of the lips; - labiomental fold (LMF) and angle; - position of the tongue at rest and function; - shape and position of the nose and its relation to the chin; - chin and chin-throat area; - the periodontal status and any pathologic condition such as caries, trauma, and malformation were also investigated; and treatment was applied; - the full face of the patient was examined from frontal and profile direction to assess the following: any degree of facial asymmetry or abnormality was observed and recorded. Panorex view was used to detect the presence and extent of any pathologic condition such as caries, periodontal status, cysts, or tumors; and treatment was applied when indicated. Standardized clinical photographs were taken preoperatively with the patient seated comfortably in relaxed position and occlusion at rest. For each patient, full face and profile photographs were taken. Photographs were taken twice, one before surgery and the
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other at 6 months after surgery. In each time, a fixed distance from the camera to the patient’s face was used. The lateral cephalograms were taken with the same cephalostat with the teeth in centric occlusion and the lips relaxed. The cephalograms were taken at the following time: preoperative (T1) and 6 months postoperative (T2). Hard and soft tissue landmarks were identified in all tracings with respect to stable reference lines.
Surgical Procedure A vestibular layered incision was performed in the anterior region of the mandible through the lower lip mucosa, midway between the depth of the labial vestibule and the vermillion border of the lower lip, with the incision extending anteriorly out into the lip and the lateral end points of the incision were in the area of mesial aspect of the canine teeth bilaterally; the incision was done down to the bone in an oblique fashion with minimal dissection of the soft tissue. A degloving procedure was performed down to the inferior border of the mandible and laterally to the area of the premolars. The mentalis muscle was stripped from the mandible in a subperiosteal plane. Great care was used to identify, isolate, and avoid trauma to the mental neurovascular bundle; the periosteum around the mental nerve at the foramina was released to allow freedom of retraction. In group 1, they were treated by the sliding genioplasty technique followed by the bony surgical technique; the midline of the bone was marked with a round bur as a straight line from the inferior border superiorly for approximately 5 mm from the anterior apices, and this mark acted as a reference mark when the inferior segment was moved anteriorly and will aid in producing a symmetrical bone cut. A second corticotomy was created with the round bur and osteotome at approximately right angles to the bone and parallel to the occlusal plane, starting at the inferior mandibular border 5 mm below the mental foramen so that the inferior alveolar nerve was not jeopardized. The lateral osteotomy was completed under the apices of the lower incisors (5 mm below the apices using the preoperative x-ray); a similar cut was made on the contralateral side to join the first cut at the vertical midline reference line, and then, below the roots of the canine teeth, separation was first performed by gentle pressure and completed over the cut to approach a complete separation. Two right-angle retractors and a chin retractor were introduced into the wound so that both lateral end points at the inferior border and at the midline could be visualized simultaneously. The inferior segment was then advanced and positioned as determined preoperatively (Fig. 1). In group 2, they were treated by the chin shield osteotomy genioplasty technique followed by the bony surgical technique; the midline of the bone was marked with a round bur as a straight line from the inferior border superiorly for approximately 5 mm
FIGURE 1. The bony cut “sliding genioplasty” group 1.
© 2014 Mutaz B. Habal, MD
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The Journal of Craniofacial Surgery • Volume 25, Number 4, July 2014
from the anterior apices, and this mark acted as a reference mark when the inferior segment was moved anteriorly and will aid in producing a symmetrical bone cut. For the osteotomies of the alveolar bone, a thin bur is used. The horizontal osteotomies are performed in such a manner that the anterior buccal cortex remains intact for an approximately 2-cm-long segment centered over the midline. The lingual cortex is completely cut throughout the entire length of the lower horizontal osteotomy. In the midline area behind the intact buccal segment, this is achieved by a corresponding angulation of the cutting bur. Care is taken to protect the lingual periosteum and soft tissue. The final shaping of the bony shield is performed by cutting the remaining buccal cortex cranially as far as possible but without compromising the apices of the anterior teeth with the bone cutter. Before mobilization, it is important to make sure that the horizontal osteotomy cuts are complete, specifically on the lingual side. The mobilization of the entire chin segment is carried out by applying controlled force with 2 sharp enamel chisels, one in the shield area and the other in the mesial area of the horizontal osteotomy. It is important to coordinate this down fracture to avoid breaking off the shield part. The osteotomized chin segment can be gradually and safely mobilized (Fig. 2). In both groups, fixation of the segment in the new position is accomplished with double Y miniplates and screws (Biomet Microfixation Corporate Headquarters, Jacksonville, FL). In both groups, the closure was performed in 2 layers. The first layer was closed with 3-0 vicryl suture placed in the assumed area of the mentalis muscle to reapproximate the edges. The second layer involved closure of the mucosa using black silk suture. A pressure pack was applied to the chin to help later edema and prevent hematoma formation. Cold application in the form of ice packs was done in the first 12 hours postoperatively, and intramuscular injection of Clindamycin of 600 mg, 2 times a day for 3 days, and Diclofenac Sodium of 75 mg immediately postoperatively for the next day, 2 times for every 12 hours, were prescribed. Intramuscular injection of Dexamethasone of 8 mg immediately postoperatively and, for the next day, 2 times for every 12 hours was prescribed; and the patients were instructed for soft diet and liquids for the first week and were dismissed in the same operative day (6–8 h) postoperatively after full recovery.
Cephalometric Assessment The Frankfort horizontal (FH) plane was chosen as a reference line for the study to minimize the effect of any additional mandibular or maxillary osteotomies. Horizontal soft tissue and hard tissue changes were recorded parallel to the FH line and perpendicular on the nasion vertical (NV), whereas the vertical soft tissue
Soft Tissue Response
FIGURE 3. Preoperative (A) and postoperative (B) profile photographs for group 1.
and hard tissue changes were recorded parallel to the NV and perpendicular on the FH line. - The advancement was measured by the change in the position of point Pg preoperatively (T1) and postoperatively (T2) from the NV line. - The points (Pg, Pg', Me, Me', and B) were measured for vertical and horizontal movements by a line from each point and perpendicular to the NV and the FH, respectively. The distance from each point to the FH and NV was measured at T1 and T2; the difference between hard tissue and soft tissue measurements will assess for the ratio of soft tissue change. - The point (Li) was measured by a line perpendicular on the esthetic line. - The labiomental angle was measured for each cephalogram, which is the angle formed between the following points: pogonion (Pg), labiomental (LMF), and labrale inferirus (Li). - The LMF depth was measured for each cephalograms by line from the LMF and perpendicular to a line connecting the pogonion (Pg) and the Li. Data were presented as mean (SD) values. All data showed normal (parametric) distribution except for B-NV (millimeters), Me-NV (millimeters), Pg-NV (millimeters), Pg'-NV (millimeters), and Li-E.line (millimeters) measurements, which showed nonparametric distribution. For parametric data, Student’s t-test was used to compare between the 2 groups. Paired t-test was used to study the changes by time within each group. For nonparametric data, Mann-Whitney test was used to compare between the 2 groups. This test is the nonparametric alternative to Student’s t-test. Wilcoxon signed-rank test was used to study the changes by time within each group. This test is the nonparametric alternative to paired t-test. The significance level was set at P ≤ 0.05. Statistical analysis was performed with IBM SPSS Statistics Version 20 for Windows (IBM Corporation, NY).
RESULTS Clinical Findings
FIGURE 2. The bony cut “chin shield genioplasty” group 2.
This study was conducted on 8 adult patients (6 women and 2 men), with age ranging from 20 to 30 years (mean, 25 y). In this study, the surgical procedure was carried out without serious complications. The blood loss was minimal, so none of the patients needed blood transfusion. The operating time was 1.5 to 2 hours. No postoperative complications were recorded such as infection, wound dehiscence, or delayed healing. Postsurgical edema was minimal and subsided completely within a week. Postoperative pain and discomfort were controlled satisfactorily by nonsteroidal antiinflammatory analgesics, and wound healing proceeded uneventfully.
© 2014 Mutaz B. Habal, MD
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FIGURE 4. Preoperative (A) and postoperative (B) profile photographs for group 2.
Clinically, there was a considerable change in the soft and hard tissues in the chin area and LMF as observed in the profile view in both groups (Figs. 3–4). The facial profile was improved because of advancement of the chin; the LMF depth decreased and become shallower in group 2 (chin shield osteotomy) than in group 1 (sliding genioplasty). On the other hand, no change in the vertical direction was observed in both groups. The remodeling patterns of the advanced segment never showed any evidence of inferior rotation or bodily displacement of the chin in the postoperative clinical assessment along the follow-up period (6 mo).
FIGURE 6. Histogram representing change by time in mean hard tissue measurements in both groups.
Osteotomy of the inferior border of the mandible can be adversely affected by 2 completely different mechanisms: first, the skeletal instability, where the advanced genial segment changes in position before osseous union, thereby rapidly altering the surgical outcome; and the second being osseous remodeling, where the advanced genial segment is slowly recontoured during the remodeling process and is a much slower pathway by which the final result may differ from the immediate postsurgical outcome.26 In this study, the rigid fixation of the genial segment prevents previous complications, and the postoperative care as well as the periodical follow-up guard against such complications.
The goal of genioplasty in profile improvement is to correct the position of the jaw line and to provide an esthetic sublabial fold and a competent lip seal. Excessive chin advancement can lead to a marked sublabial fold and increased soft tissue tension resulting in labial incompetence.27 There have been many reports in the literature of hard and soft tissue changes after orthognathic surgery, but few were about the genioplasty alone. This is because advancement genioplasty was rarely carried out alone; it is usually carried out in combination of the bilateral sagittal split osteotomy. There are many advantages of sliding genioplasty. First, it can be used to treat microgenia as well as macrogenia. Second, it is simple to perform. Third, the amount of bone resorption is small, and the esthetic result is stable. However, it presents complications as well, for example, neurosensory deficiency, hematoma, infection, fracture of the mandibular body, and bone necrosis.28 Another complication of the sliding genioplasty is the increase in LMF depth, so the goal of the chin shield genioplasty is to avoid the deep LMF depth, improve the labial competence, and correct the jaw line.27 In this study, the patients were satisfied with the outcome of both techniques. Some of the studies were against the use of pogonion as a reference point to study the exact measurements of genial segment because bony remodeling would invalidate any conclusion about skeletal stability.29 Defreitas et al27 described the pogonion as an important point to be assessed in a genioplasty study as it is the unaltered bony landmark of the chin prominence. In the current study, the pogonion (Pg) was used as a reference point to study the measurements of genial segment in horizontal and vertical directions; in addition, the menton (Me) point was used as a reference point in both directions, which is due to the stability and reproducibility of that point in the bone and in cephalometry. The remodeling patterns of the advanced segment never showed any evidence of inferior rotation or bodily displacement
FIGURE 5. Preoperative (A) and postoperative (B) cephalograms.
FIGURE 7. Histogram representing change by time in mean soft tissue measurements in both groups.
Radiographic Finding Cephalometric tracing analysis revealed the following: (1) the mean (SD) change of bony pogonion (Pg) was 4.8 (0.3) mm in group 1 and 8.2 (2.6) mm in group 2. (2) The mean (SD) change of soft tissue pogonion (Pg') was 4.7 (0.3) mm in group 1 and 6.2 (4.8) mm in group 2. (3) The mean (SD) change in the labiomental depth in group 1 was 0.9 (0.3) mm and 0.2 (0.5) mm in group 2. So the chin shield genioplasty of group 2 contributed to a less LMF depth (Figs. 5–8; Tables 1–2).
DISCUSSION
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© 2014 Mutaz B. Habal, MD
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The Journal of Craniofacial Surgery • Volume 25, Number 4, July 2014
Soft Tissue Response
TABLE 2. Mean Difference, SD Values, and Results of the Changes by Time in Soft Tissue Measurements of Group 2 Measurement
Period
Mean Difference
SD
P value
Pg'-FH, mm
T1–T2 T1–T2 T1–T2 T1–T2 T1–T2 T1–T2 T1–T2
1.2 −6.2 4.8 −10.2 0.2 −4 −16.3
1.6 4.8 5.8 7 0.5 1.7 6
0.336 0.029 0.285 0.019* 0.074 0.102 0.043*
Pg'-NV, mm Me'-FH, mm Me'-NV, mm LMF depth Li-E.line LMF angle (◦) FIGURE 8. Histogram representing change by time in mean LMF angle measurements in each group.
*Significant at P ≤ 0.05.
in the postoperative evaluation of our study, which correlates with other studies.26,30 The soft tissue profile change seen as the effect of advancement of genial segment has been studied differently by various authors. The ratio of horizontal changes for osseous to soft tissues ranges from 1:0.6 to 1:1 in the literature.29 Jensen et al31 showed that, with mandibular advancement, the soft tissue will advance in graduated fashion, ranging from 72% at the lower lip to 100% at the pogonion. Mammaerts and Marxer32 showed pogonion to soft tissue pogonion of 1:1.03; Hernandez-Orsini et al33 also showed a 1:1 immediate postoperative change. El Sweify34 showed that the ratio of the hard to soft tissue changes after advancement genioplasty of 14 clinical cases was 1:0.9, which correlates with the literature. In our study, for group 1 (sliding genioplasty), the mean ratio of horizontal change was 1:0.83, whereas for group 2 (chin shield genioplasty), it was 1:0.99. Both results correlate with the literature. The answer of this variation lies in that different genioplasty techniques were used. The correlation of the soft tissue changes is an often overlooked aspect of treatment of patients with malocclusion or dentofacial deformity. However, these changes are directly related with skeletal changes and have considerable impact on facial esthetics. Moreover, it is the soft tissue changes that can be appreciated and noticed by the patient. Considerable changes could be seen in the soft tissue profiles as a result of treatment. After surgery, all patients had straighter facial profiles, more harmonious lip profiles, and deeper LMFs. The shape of the LMF is influenced by all the factors that control lower lip contour and soft tissue chin contour. A direct correlation was found between the change in labiomental sulcus depth and the amount of advancement of chin. Shaughnessy et al30 demonstrated net increase of the labiomental sulcus (LMF) depth by 1.8 mm; in this study, there was an increase in depth of the LMF
TABLE 1. Mean Difference, SD Values, and Results of the Changes by Time in Soft Tissue Measurements of Group 1 Measurement
Period
Mean Difference
SD
P value
Pg'-FH, mm
T1–T2 T1–T2 T1–T2 T1–T2 T1–T2 T1–T2 T1–T2
−0.5 −4.7 −0.7 −2.2 −0.9 −2.3 2.7
1.3 0.3 5.5 0.8 0.3 1.4 0.6
0.580 0.023* 0.853 0.09* 0.43* 0.102 0.015*
Pg'-NV, mm Me'-FH, mm Me'-NV, mm LMF depth Li-E.line LMF angle (◦)
*Significant at P ≤ 0.05.
postoperatively by 0.9 mm in group 1, whereas in group 2, the LMF depth showed no difference postoperatively. The cephalometric analysis was used in the current study in to analyze the case preoperatively and to study the changes produced by surgery and relapse thereafter depending on both linear and angular measurements. The importance of cephalometry in diagnosis and treatment planning before orthognathic procedures has been repeatedly stressed in previous studies.35–37 Landmarkbased analysis using linear and angular measurements were reported as the most popular method for cephalometric analysis among physicians.38 The following can be concluded: - The ratio of soft tissue response to bony movement in the sliding genioplasty technique was 1:83, whereas in the chin shield genioplasty technique, it was 1:0.99. - In the chin shield genioplasty technique, the increase in LMF depth was less than in the sliding genioplasty technique. - Effects of advancement genioplasty on the lips were small. No change in lip position could be observed.
REFERENCES 1. McCarthy JG, Ruff GL. The chin. Clin Plast Surg 1988;15:125 2. Precious DS, Delaire J. Correction of anterior mandibular vertical excess: the functional genioplasty. Oral Surg Oral Med Oral Pathol 1985;59:229 3. McBride KL, Bell WH. Chin surgery. In: Bell WH, Proffit WR, White RP, eds. Surgical Correction of Dentofacial Deformities. Philadelphia: W.B. Saunders, 1980:1210 4. Sher MR. Surgical placement of a chin cleft concomitant with genioplasty. J Oral Surg 1980;38:62 5. Spira M. Surgery of the chin. In: Baily BJ, Holt GR, eds. Surgery of the Mandible. New York: Thieme Medical Publishers, 1987:120 6. Trauner R, Obwegesser H. The surgical correction of mandibular prognathism and retrognathia with consideration of genioplasty. J Oral Surg 1957;10:677–689 7. Kawamoto HK Jr. Osseous Genioplasty. Aesthet Surg J 2000;20:509–518 8. Cohen SR. Genioplasty. In: Achauer BM, Eriksson E, Guyuron B, et al, eds. Plastic Surgery: Indications, Operations and Outcomes Vol. 5. Philadelphia: Mosby, 2000:2683 9. McCarthy JG, Ruff GL, Zide BM. A surgical system for the correction of bony chin deformity. Clin Plast Surg 1991;18:139 10. Guyuron B, Michelow B, Willis L. Practical classification of chin deformities. Aesthetic Plast Surg 1995;19:7 11. Ward JL, Garri JI, Wolfe SA. The osseous genioplasty. Chin Plastic Surg 2007;34:485 12. Gilles H, Millard DR Jr. The principles and art of plastic surgery. 1st ed. Boston: Little and Brown 1957
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13. Lindquist CC, Obeid G. Complication of genioplasty done alone or in combination with sagittal split ramus osteotomy. Oral Surg Oral Med Oral Pathol 1988;66:13 14. Cunningham LL, Tiner BD, Clark GM, et al. A comparison of questionnaire versus monofilament assessment of neurosensory deficit. J Oral Maxillofac Surg 1996;54 15. Wolford LM, Bates JD. Surgical modification for the correction of chin deformities. J Oral Surg 1988;66:279 16. Yamazaki M, Cheng J, Nomura T, et al. Maxillary odontogenic keratocyst with respiratory epithelium. J Oral Pathol Med 2003;32 17. Koutlas IG, Gillum RB, Harris MW, et al. Surgical (implantation) cyst of mandible with ciliated respiratory epithelial lining. J Oral Maxillofac Surg 2002;60:324 18. Bell WH, Bammer JA, Mcbride KL, et al. Quoted from 196: reduction genioplasty: surgical techniques and soft tissue changes. J Oral Surg 1981;51:471 19. Coghlan KM, Irvine GH. Neurological damage after sagittal split osteotomy. Int Oral Maxillofac Surg 1986;15:369 20. Van BT, Tsele BL, Mommaerts MY, et al. Creating lip seal by macillofacial osteotomies, a retrospective cephalometric study. J Craniomaxillofac Surg 1995;23:165 21. Charles L, Clark DDS, Van MAJ. Management of mentalis muscle dysfunction after advancement genioplasty. J Oral Maxillofac Surg 1998;62:611 22. Scheerlinck JP, Stoelinga PJ, Blijdrop PA, et al. Split advancement osteotomies stabilized with miniplates. A 2–5 years follow up. Int J Oral Maxillofac Surg 1994;23:127 23. Van Sickels JE, Smith CV, Tiner BD, et al. Hard and soft tissue predictability with advancement genioplasty. Oral Surg Oral Med Oral Pathol 1994;77:218 24. Mommaerts MY, Van Hemelen G, Saunders K. High labial incisions for genioplasty. Br J Oral Maxillofac Surg 1997;35:398 25. Mobarark KA, Espeland L, Krogstad O, et al. Soft tissue profile changes following mandibular advancement surgery: predictability and long-term outcome. Am J Orthod Dentofacial Orthop 2001;119:353
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26. Triaca A, Furrer T, Minoretti R. Chin shield osteotomy—a new genioplasty technique avoiding a deep mento-labial fold in order to increase the labial competence. Int J Oral Maxillofac Surg 2009;38:1201–1225 27. Defreitas CE, Ellis E, Sinn DE. A retrospective study of advancement genioplasty using special bone Plate. J Oral Maxillofac Surg 1992;50:340 28. Mercuri LG, Laskin DM. A vascular necrosis after anterior horizontal augmentation genioplasty. J Oral Surg 1977;35:296 29. Davis WH, Davis CL, Daly BW. Long term bony and soft tissue stability following advancement genioplasty. J Oral Maxillofac Surg 1988;46:731 30. Shaughnessy S, Mobark KA, Hogevold HE. Long-term skeletal and soft tissue response after advancement genioplasty. Am J Orthod Dentofacial Orthop 2006;130:8 31. Jensen AC, Sinclair PM, Wolford LM. Soft tissue changes associated with double jaw surgery. Am J Orthod Dentofacial Orthop 1992;101:266 32. Mommaerts MY, Marxer H. A cephalometric analysis of the long term soft tissue profile changes which accompany the advancement of the mandible by sagittal split ramus osteotomies. J Craniomaxillofac Surg 1987;15:127 33. Hernandez-Orsini R, Jacobson A, Sarver DM. Short and long term soft tissue profile changes after mandibular advancements using rigid fixation technique. Int J Adult Orthod Orthognath Surg 1989;4:209 34. El Sweify AA. Soft tissue change after genioplasty [doctor’s degree thesis]. Cairo University, 1993 35. Nordenram A. Oral surgical correction of mandibular protrusion. Br J Oral Surg 1968;6:64 36. McNeil RW, Proffit WR, White RP. Cephalometric prediction for orthognathic surgery. Angle Orthod 1972;42:154 37. Burstone CJ, James RB, Legan HC. Cephalometric for orthognathic surgery. J Oral Surg 1978;36:269 38. Kumar V, Ludlow JB, Mol A, et al. Comparison of conventional and cone beam CT synthesized cephalograms. Dentomaxillofac Radiol 2007;36:9
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
Soft Tissue Response After Chin Advancement Using Two Different Genioplasty Techniques: A Preliminary Technical Comparative Study Sameh Ahemd Seifeldin, BDS, MSc,*† Maha Shawky, BDS, MSc,‡ and Saleem M. Hicham Nouman, BDS† Purpose: The aim of this study was to evaluate soft tissue response after chin advancement using 2 different genioplasty techniques. Methods: The study included 8 adult patients who were divided equally into 2 groups: group 1 was surgically treated by sliding genioplasty, and group 2 was surgically treated by chin shield genioplasty for the correction of retruded or deficient chin. Lateral cephalograms were taken twice: immediately preoperative and 6 months postoperative. Results: The mean (SD) change of soft tissue pogonion (Pg') was 4.7 (0.3) mm in group 1, whereas in group 2, the mean (SD) change of soft tissue pogonion (Pg’) was 6.2 (4.8) mm. The mean (SD) change in the labiomental depth in group 1 was 0.9 (0.3) mm, whereas in group 2, it was 0.2 (0.5) mm. So in group 2, chin shield genioplasty contributed to a less labiomental fold depth. The ratio of soft tissue response to bony movement in the sliding genioplasty technique was 1:0.83, whereas in the chin shield genioplasty technique, it was 1:0.99. Conclusions: In the chin shield genioplasty technique, the increase in labiomental fold depth was less than in the sliding genioplasty technique. Key Words: Sliding genioplasty, chin shield genioplasty, soft tissue change (J Craniofac Surg 2014;25: 1383–1388)
T
he chin is a prominent facial feature that plays an important role in the overall facial appearance. The deficiency of chin is one of the deformities that cause facial disfigurement. Surgical correction of cosmetic deformities of the chin can be performed by either chin augmentation with an implant or by osteotomy and advancement of the bony mentum. Chin augmentation using alloplastic implants is an effective means of correcting an antero-posterior chin deficiency (microgenia). The chin is an important and often neglected feature
From the *King Saud University, Saudi Arabia; †Cairo University, Egypt; and ‡King Abdullaziz University, Jeddah, Saudi Arabia. Received October 24, 2013. Accepted for publication February 8, 2014. Address correspondence and reprint requests to Sameh Ahmed Seifeldin, BDs, Msc, PhD, King Saud University, B.O. 60169, Riyadh 11545, Saudi Arabia; E-mail: [email protected] No research center provided funding or budget for the research work, and all is done with the authors’ own expenses. The authors report no conflicts of interest. Copyright © 2014 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000000863
of facial balance. Correction of chin recession has always been difficult because of the bony substance in which to perform osteotomy is always insufficient. So, the surgical correction of these deformities is one of the most challenging and intriguing aspects of oral surgery. Genioplasty is a useful procedure in esthetic surgery and can be combined with other procedures to obtain an optimal esthetic outcome.1 It has been shown that the public places more emphasis on the lips than on other facial structures when evaluating facial esthetics. This might explain why the patient’s overall satisfaction when undergoing maxillofacial surgery is primarily driven by the final position of the soft tissues. On that basis, the effects of orthognathic surgery on the soft tissue profile, especially the lips, must be understood and predictable.2 Genioplasty has become a routine procedure in the correction of dentofacial deformities. In addition to allowing improvement of the profile, functional genioplasty makes it possible to obtain muscular equilibrium in the labiomental and even the nasolabial region of the face.2 The procedure of genioplasty can be performed as a sole procedure or in combination with other surgical procedures in the maxilla and/or the mandible.3–5 The genioplasty procedure is differentiated further and classified by variations in technique, the reciprocal movements of the mandible segments, and the final result desired.6–10 Concerning the different genioplasty techniques, Ward et al11 reported that, in the sliding genioplasty, the osteotomy segment slides anteriorly or posteriorly, and the vertical dimension of the lower third of the face is altered accordingly. However, in the jumping genioplasty, the caudal segment is moved anteriorly and placed in front of the mandible, almost like an implant. The lower soft tissue attachments of the segment should be preserved to avoid bone resorption. This nomenclature was used for the first time by Gilles and Millard12 who indicates the attempt to improve the sagittal projection of the chin and decrease the height of the lower facial third. In graft genioplasty or interpositional genioplasty, the advancement is achieved by the interpositioning of bone graft between the mandible segments to advance the chin as well as increase the lower facial height (sandwich horizontal osteotomy). On the other hand, wedge genioplasty is involving the removal of a segment of the bone. Two horizontal osteotomies parallel to each other and to the occlusal plane are performed, and after the caudal cut is made, the segment between the osteotomies is resected.11 The stepladder/two-tiered genioplasty is used for important sagittal advancement without significant modification of the height of the lower facial third. Two osteotomies are performed, and the lower segment is advanced sagittally over an already-advanced proximal segment. In the centering genioplasty, vertical and horizontal asymmetries can be corrected. Depending on the asymmetry, a wedge of bone can be resected on the longer side and, if needed, mirror imaged to lengthen the contralateral deficient side.11
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Complications of genioplasty include mental nerve affection and loss of tooth vitality,13 change of lower labial sulcus depth, wound scaring,14,15 apical root resorption, loss of dental vitality, and periodontal pockets, which could be reduced by the use of piezoelectric cut.16,17 Neuroparaxia and neurotmesis of the nerve,18 “witch’s chin” deformity or lip incompetence, and drooling are common complications due to failure to reapproximate the mentalis muscle at the time of wound closure.19,20 Added to the mentalis muscle is the dysfunction manifested by an unsightly bulge of mental skin. Fortunately, this complication seems to be very rare.21 The soft tissue profile has emerged as perhaps the most important consideration for planning surgery and assessing treatment outcomes.22 This may be possibly because of the nonlinear relationship between horizontal hard tissue and soft tissue changes. Another possibility is that vertical movements influence the soft tissue movement of the chin. The relationship between the hard tissue and the soft tissue changes may be more complex than described earlier because soft tissue morphology, thickness, posture, and tonicity vary from person to person. The final soft tissue appearance may be dependent on the type of surgical technique used and on complications (such as scarring) that may arise from the surgical procedure. The accuracy of any prediction, however achieved, should be dependent on knowledge of the behavior of soft tissues.23 It has been found that the results of soft tissue changes in advancement genioplasty may be affected by the direction and magnitude of the genial segment movement and the design of the mucosal and osseous incisions.24 Presurgical predictions are important tools to demonstrate possible postsurgical results; those serve as an instrument for patient communication and provide a goal for operative treatment planning.25
PATIENTS AND METHODS This study was conducted on 8 adult patients. All patients were selected on the basis that their main problem was a deficient chin or retruded chin that required surgical correction by advancement genioplasty. The patients were divided into 2 equal groups: group 1 was treated by sliding genioplasty, whereas group 2 was treated by chin shield osteotomy genioplasty. For each, the following data were recorded: medical history, clinical examination, photographs, and radiographs including panorex view and lateral cephalometry. Clinical examination of oral structures was undertaken in a systematic fashion as follows: - the lips, cheeks, tongue, chin, and palate were examined; - competence, texture, thickness, and behavior of the lips; - labiomental fold (LMF) and angle; - position of the tongue at rest and function; - shape and position of the nose and its relation to the chin; - chin and chin-throat area; - the periodontal status and any pathologic condition such as caries, trauma, and malformation were also investigated; and treatment was applied; - the full face of the patient was examined from frontal and profile direction to assess the following: any degree of facial asymmetry or abnormality was observed and recorded. Panorex view was used to detect the presence and extent of any pathologic condition such as caries, periodontal status, cysts, or tumors; and treatment was applied when indicated. Standardized clinical photographs were taken preoperatively with the patient seated comfortably in relaxed position and occlusion at rest. For each patient, full face and profile photographs were taken. Photographs were taken twice, one before surgery and the
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other at 6 months after surgery. In each time, a fixed distance from the camera to the patient’s face was used. The lateral cephalograms were taken with the same cephalostat with the teeth in centric occlusion and the lips relaxed. The cephalograms were taken at the following time: preoperative (T1) and 6 months postoperative (T2). Hard and soft tissue landmarks were identified in all tracings with respect to stable reference lines.
Surgical Procedure A vestibular layered incision was performed in the anterior region of the mandible through the lower lip mucosa, midway between the depth of the labial vestibule and the vermillion border of the lower lip, with the incision extending anteriorly out into the lip and the lateral end points of the incision were in the area of mesial aspect of the canine teeth bilaterally; the incision was done down to the bone in an oblique fashion with minimal dissection of the soft tissue. A degloving procedure was performed down to the inferior border of the mandible and laterally to the area of the premolars. The mentalis muscle was stripped from the mandible in a subperiosteal plane. Great care was used to identify, isolate, and avoid trauma to the mental neurovascular bundle; the periosteum around the mental nerve at the foramina was released to allow freedom of retraction. In group 1, they were treated by the sliding genioplasty technique followed by the bony surgical technique; the midline of the bone was marked with a round bur as a straight line from the inferior border superiorly for approximately 5 mm from the anterior apices, and this mark acted as a reference mark when the inferior segment was moved anteriorly and will aid in producing a symmetrical bone cut. A second corticotomy was created with the round bur and osteotome at approximately right angles to the bone and parallel to the occlusal plane, starting at the inferior mandibular border 5 mm below the mental foramen so that the inferior alveolar nerve was not jeopardized. The lateral osteotomy was completed under the apices of the lower incisors (5 mm below the apices using the preoperative x-ray); a similar cut was made on the contralateral side to join the first cut at the vertical midline reference line, and then, below the roots of the canine teeth, separation was first performed by gentle pressure and completed over the cut to approach a complete separation. Two right-angle retractors and a chin retractor were introduced into the wound so that both lateral end points at the inferior border and at the midline could be visualized simultaneously. The inferior segment was then advanced and positioned as determined preoperatively (Fig. 1). In group 2, they were treated by the chin shield osteotomy genioplasty technique followed by the bony surgical technique; the midline of the bone was marked with a round bur as a straight line from the inferior border superiorly for approximately 5 mm
FIGURE 1. The bony cut “sliding genioplasty” group 1.
© 2014 Mutaz B. Habal, MD
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The Journal of Craniofacial Surgery • Volume 25, Number 4, July 2014
from the anterior apices, and this mark acted as a reference mark when the inferior segment was moved anteriorly and will aid in producing a symmetrical bone cut. For the osteotomies of the alveolar bone, a thin bur is used. The horizontal osteotomies are performed in such a manner that the anterior buccal cortex remains intact for an approximately 2-cm-long segment centered over the midline. The lingual cortex is completely cut throughout the entire length of the lower horizontal osteotomy. In the midline area behind the intact buccal segment, this is achieved by a corresponding angulation of the cutting bur. Care is taken to protect the lingual periosteum and soft tissue. The final shaping of the bony shield is performed by cutting the remaining buccal cortex cranially as far as possible but without compromising the apices of the anterior teeth with the bone cutter. Before mobilization, it is important to make sure that the horizontal osteotomy cuts are complete, specifically on the lingual side. The mobilization of the entire chin segment is carried out by applying controlled force with 2 sharp enamel chisels, one in the shield area and the other in the mesial area of the horizontal osteotomy. It is important to coordinate this down fracture to avoid breaking off the shield part. The osteotomized chin segment can be gradually and safely mobilized (Fig. 2). In both groups, fixation of the segment in the new position is accomplished with double Y miniplates and screws (Biomet Microfixation Corporate Headquarters, Jacksonville, FL). In both groups, the closure was performed in 2 layers. The first layer was closed with 3-0 vicryl suture placed in the assumed area of the mentalis muscle to reapproximate the edges. The second layer involved closure of the mucosa using black silk suture. A pressure pack was applied to the chin to help later edema and prevent hematoma formation. Cold application in the form of ice packs was done in the first 12 hours postoperatively, and intramuscular injection of Clindamycin of 600 mg, 2 times a day for 3 days, and Diclofenac Sodium of 75 mg immediately postoperatively for the next day, 2 times for every 12 hours, were prescribed. Intramuscular injection of Dexamethasone of 8 mg immediately postoperatively and, for the next day, 2 times for every 12 hours was prescribed; and the patients were instructed for soft diet and liquids for the first week and were dismissed in the same operative day (6–8 h) postoperatively after full recovery.
Cephalometric Assessment The Frankfort horizontal (FH) plane was chosen as a reference line for the study to minimize the effect of any additional mandibular or maxillary osteotomies. Horizontal soft tissue and hard tissue changes were recorded parallel to the FH line and perpendicular on the nasion vertical (NV), whereas the vertical soft tissue
Soft Tissue Response
FIGURE 3. Preoperative (A) and postoperative (B) profile photographs for group 1.
and hard tissue changes were recorded parallel to the NV and perpendicular on the FH line. - The advancement was measured by the change in the position of point Pg preoperatively (T1) and postoperatively (T2) from the NV line. - The points (Pg, Pg', Me, Me', and B) were measured for vertical and horizontal movements by a line from each point and perpendicular to the NV and the FH, respectively. The distance from each point to the FH and NV was measured at T1 and T2; the difference between hard tissue and soft tissue measurements will assess for the ratio of soft tissue change. - The point (Li) was measured by a line perpendicular on the esthetic line. - The labiomental angle was measured for each cephalogram, which is the angle formed between the following points: pogonion (Pg), labiomental (LMF), and labrale inferirus (Li). - The LMF depth was measured for each cephalograms by line from the LMF and perpendicular to a line connecting the pogonion (Pg) and the Li. Data were presented as mean (SD) values. All data showed normal (parametric) distribution except for B-NV (millimeters), Me-NV (millimeters), Pg-NV (millimeters), Pg'-NV (millimeters), and Li-E.line (millimeters) measurements, which showed nonparametric distribution. For parametric data, Student’s t-test was used to compare between the 2 groups. Paired t-test was used to study the changes by time within each group. For nonparametric data, Mann-Whitney test was used to compare between the 2 groups. This test is the nonparametric alternative to Student’s t-test. Wilcoxon signed-rank test was used to study the changes by time within each group. This test is the nonparametric alternative to paired t-test. The significance level was set at P ≤ 0.05. Statistical analysis was performed with IBM SPSS Statistics Version 20 for Windows (IBM Corporation, NY).
RESULTS Clinical Findings
FIGURE 2. The bony cut “chin shield genioplasty” group 2.
This study was conducted on 8 adult patients (6 women and 2 men), with age ranging from 20 to 30 years (mean, 25 y). In this study, the surgical procedure was carried out without serious complications. The blood loss was minimal, so none of the patients needed blood transfusion. The operating time was 1.5 to 2 hours. No postoperative complications were recorded such as infection, wound dehiscence, or delayed healing. Postsurgical edema was minimal and subsided completely within a week. Postoperative pain and discomfort were controlled satisfactorily by nonsteroidal antiinflammatory analgesics, and wound healing proceeded uneventfully.
© 2014 Mutaz B. Habal, MD
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FIGURE 4. Preoperative (A) and postoperative (B) profile photographs for group 2.
Clinically, there was a considerable change in the soft and hard tissues in the chin area and LMF as observed in the profile view in both groups (Figs. 3–4). The facial profile was improved because of advancement of the chin; the LMF depth decreased and become shallower in group 2 (chin shield osteotomy) than in group 1 (sliding genioplasty). On the other hand, no change in the vertical direction was observed in both groups. The remodeling patterns of the advanced segment never showed any evidence of inferior rotation or bodily displacement of the chin in the postoperative clinical assessment along the follow-up period (6 mo).
FIGURE 6. Histogram representing change by time in mean hard tissue measurements in both groups.
Osteotomy of the inferior border of the mandible can be adversely affected by 2 completely different mechanisms: first, the skeletal instability, where the advanced genial segment changes in position before osseous union, thereby rapidly altering the surgical outcome; and the second being osseous remodeling, where the advanced genial segment is slowly recontoured during the remodeling process and is a much slower pathway by which the final result may differ from the immediate postsurgical outcome.26 In this study, the rigid fixation of the genial segment prevents previous complications, and the postoperative care as well as the periodical follow-up guard against such complications.
The goal of genioplasty in profile improvement is to correct the position of the jaw line and to provide an esthetic sublabial fold and a competent lip seal. Excessive chin advancement can lead to a marked sublabial fold and increased soft tissue tension resulting in labial incompetence.27 There have been many reports in the literature of hard and soft tissue changes after orthognathic surgery, but few were about the genioplasty alone. This is because advancement genioplasty was rarely carried out alone; it is usually carried out in combination of the bilateral sagittal split osteotomy. There are many advantages of sliding genioplasty. First, it can be used to treat microgenia as well as macrogenia. Second, it is simple to perform. Third, the amount of bone resorption is small, and the esthetic result is stable. However, it presents complications as well, for example, neurosensory deficiency, hematoma, infection, fracture of the mandibular body, and bone necrosis.28 Another complication of the sliding genioplasty is the increase in LMF depth, so the goal of the chin shield genioplasty is to avoid the deep LMF depth, improve the labial competence, and correct the jaw line.27 In this study, the patients were satisfied with the outcome of both techniques. Some of the studies were against the use of pogonion as a reference point to study the exact measurements of genial segment because bony remodeling would invalidate any conclusion about skeletal stability.29 Defreitas et al27 described the pogonion as an important point to be assessed in a genioplasty study as it is the unaltered bony landmark of the chin prominence. In the current study, the pogonion (Pg) was used as a reference point to study the measurements of genial segment in horizontal and vertical directions; in addition, the menton (Me) point was used as a reference point in both directions, which is due to the stability and reproducibility of that point in the bone and in cephalometry. The remodeling patterns of the advanced segment never showed any evidence of inferior rotation or bodily displacement
FIGURE 5. Preoperative (A) and postoperative (B) cephalograms.
FIGURE 7. Histogram representing change by time in mean soft tissue measurements in both groups.
Radiographic Finding Cephalometric tracing analysis revealed the following: (1) the mean (SD) change of bony pogonion (Pg) was 4.8 (0.3) mm in group 1 and 8.2 (2.6) mm in group 2. (2) The mean (SD) change of soft tissue pogonion (Pg') was 4.7 (0.3) mm in group 1 and 6.2 (4.8) mm in group 2. (3) The mean (SD) change in the labiomental depth in group 1 was 0.9 (0.3) mm and 0.2 (0.5) mm in group 2. So the chin shield genioplasty of group 2 contributed to a less LMF depth (Figs. 5–8; Tables 1–2).
DISCUSSION
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The Journal of Craniofacial Surgery • Volume 25, Number 4, July 2014
Soft Tissue Response
TABLE 2. Mean Difference, SD Values, and Results of the Changes by Time in Soft Tissue Measurements of Group 2 Measurement
Period
Mean Difference
SD
P value
Pg'-FH, mm
T1–T2 T1–T2 T1–T2 T1–T2 T1–T2 T1–T2 T1–T2
1.2 −6.2 4.8 −10.2 0.2 −4 −16.3
1.6 4.8 5.8 7 0.5 1.7 6
0.336 0.029 0.285 0.019* 0.074 0.102 0.043*
Pg'-NV, mm Me'-FH, mm Me'-NV, mm LMF depth Li-E.line LMF angle (◦) FIGURE 8. Histogram representing change by time in mean LMF angle measurements in each group.
*Significant at P ≤ 0.05.
in the postoperative evaluation of our study, which correlates with other studies.26,30 The soft tissue profile change seen as the effect of advancement of genial segment has been studied differently by various authors. The ratio of horizontal changes for osseous to soft tissues ranges from 1:0.6 to 1:1 in the literature.29 Jensen et al31 showed that, with mandibular advancement, the soft tissue will advance in graduated fashion, ranging from 72% at the lower lip to 100% at the pogonion. Mammaerts and Marxer32 showed pogonion to soft tissue pogonion of 1:1.03; Hernandez-Orsini et al33 also showed a 1:1 immediate postoperative change. El Sweify34 showed that the ratio of the hard to soft tissue changes after advancement genioplasty of 14 clinical cases was 1:0.9, which correlates with the literature. In our study, for group 1 (sliding genioplasty), the mean ratio of horizontal change was 1:0.83, whereas for group 2 (chin shield genioplasty), it was 1:0.99. Both results correlate with the literature. The answer of this variation lies in that different genioplasty techniques were used. The correlation of the soft tissue changes is an often overlooked aspect of treatment of patients with malocclusion or dentofacial deformity. However, these changes are directly related with skeletal changes and have considerable impact on facial esthetics. Moreover, it is the soft tissue changes that can be appreciated and noticed by the patient. Considerable changes could be seen in the soft tissue profiles as a result of treatment. After surgery, all patients had straighter facial profiles, more harmonious lip profiles, and deeper LMFs. The shape of the LMF is influenced by all the factors that control lower lip contour and soft tissue chin contour. A direct correlation was found between the change in labiomental sulcus depth and the amount of advancement of chin. Shaughnessy et al30 demonstrated net increase of the labiomental sulcus (LMF) depth by 1.8 mm; in this study, there was an increase in depth of the LMF
TABLE 1. Mean Difference, SD Values, and Results of the Changes by Time in Soft Tissue Measurements of Group 1 Measurement
Period
Mean Difference
SD
P value
Pg'-FH, mm
T1–T2 T1–T2 T1–T2 T1–T2 T1–T2 T1–T2 T1–T2
−0.5 −4.7 −0.7 −2.2 −0.9 −2.3 2.7
1.3 0.3 5.5 0.8 0.3 1.4 0.6
0.580 0.023* 0.853 0.09* 0.43* 0.102 0.015*
Pg'-NV, mm Me'-FH, mm Me'-NV, mm LMF depth Li-E.line LMF angle (◦)
*Significant at P ≤ 0.05.
postoperatively by 0.9 mm in group 1, whereas in group 2, the LMF depth showed no difference postoperatively. The cephalometric analysis was used in the current study in to analyze the case preoperatively and to study the changes produced by surgery and relapse thereafter depending on both linear and angular measurements. The importance of cephalometry in diagnosis and treatment planning before orthognathic procedures has been repeatedly stressed in previous studies.35–37 Landmarkbased analysis using linear and angular measurements were reported as the most popular method for cephalometric analysis among physicians.38 The following can be concluded: - The ratio of soft tissue response to bony movement in the sliding genioplasty technique was 1:83, whereas in the chin shield genioplasty technique, it was 1:0.99. - In the chin shield genioplasty technique, the increase in LMF depth was less than in the sliding genioplasty technique. - Effects of advancement genioplasty on the lips were small. No change in lip position could be observed.
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13. Lindquist CC, Obeid G. Complication of genioplasty done alone or in combination with sagittal split ramus osteotomy. Oral Surg Oral Med Oral Pathol 1988;66:13 14. Cunningham LL, Tiner BD, Clark GM, et al. A comparison of questionnaire versus monofilament assessment of neurosensory deficit. J Oral Maxillofac Surg 1996;54 15. Wolford LM, Bates JD. Surgical modification for the correction of chin deformities. J Oral Surg 1988;66:279 16. Yamazaki M, Cheng J, Nomura T, et al. Maxillary odontogenic keratocyst with respiratory epithelium. J Oral Pathol Med 2003;32 17. Koutlas IG, Gillum RB, Harris MW, et al. Surgical (implantation) cyst of mandible with ciliated respiratory epithelial lining. J Oral Maxillofac Surg 2002;60:324 18. Bell WH, Bammer JA, Mcbride KL, et al. Quoted from 196: reduction genioplasty: surgical techniques and soft tissue changes. J Oral Surg 1981;51:471 19. Coghlan KM, Irvine GH. Neurological damage after sagittal split osteotomy. Int Oral Maxillofac Surg 1986;15:369 20. Van BT, Tsele BL, Mommaerts MY, et al. Creating lip seal by macillofacial osteotomies, a retrospective cephalometric study. J Craniomaxillofac Surg 1995;23:165 21. Charles L, Clark DDS, Van MAJ. Management of mentalis muscle dysfunction after advancement genioplasty. J Oral Maxillofac Surg 1998;62:611 22. Scheerlinck JP, Stoelinga PJ, Blijdrop PA, et al. Split advancement osteotomies stabilized with miniplates. A 2–5 years follow up. Int J Oral Maxillofac Surg 1994;23:127 23. Van Sickels JE, Smith CV, Tiner BD, et al. Hard and soft tissue predictability with advancement genioplasty. Oral Surg Oral Med Oral Pathol 1994;77:218 24. Mommaerts MY, Van Hemelen G, Saunders K. High labial incisions for genioplasty. Br J Oral Maxillofac Surg 1997;35:398 25. Mobarark KA, Espeland L, Krogstad O, et al. Soft tissue profile changes following mandibular advancement surgery: predictability and long-term outcome. Am J Orthod Dentofacial Orthop 2001;119:353
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26. Triaca A, Furrer T, Minoretti R. Chin shield osteotomy—a new genioplasty technique avoiding a deep mento-labial fold in order to increase the labial competence. Int J Oral Maxillofac Surg 2009;38:1201–1225 27. Defreitas CE, Ellis E, Sinn DE. A retrospective study of advancement genioplasty using special bone Plate. J Oral Maxillofac Surg 1992;50:340 28. Mercuri LG, Laskin DM. A vascular necrosis after anterior horizontal augmentation genioplasty. J Oral Surg 1977;35:296 29. Davis WH, Davis CL, Daly BW. Long term bony and soft tissue stability following advancement genioplasty. J Oral Maxillofac Surg 1988;46:731 30. Shaughnessy S, Mobark KA, Hogevold HE. Long-term skeletal and soft tissue response after advancement genioplasty. Am J Orthod Dentofacial Orthop 2006;130:8 31. Jensen AC, Sinclair PM, Wolford LM. Soft tissue changes associated with double jaw surgery. Am J Orthod Dentofacial Orthop 1992;101:266 32. Mommaerts MY, Marxer H. A cephalometric analysis of the long term soft tissue profile changes which accompany the advancement of the mandible by sagittal split ramus osteotomies. J Craniomaxillofac Surg 1987;15:127 33. Hernandez-Orsini R, Jacobson A, Sarver DM. Short and long term soft tissue profile changes after mandibular advancements using rigid fixation technique. Int J Adult Orthod Orthognath Surg 1989;4:209 34. El Sweify AA. Soft tissue change after genioplasty [doctor’s degree thesis]. Cairo University, 1993 35. Nordenram A. Oral surgical correction of mandibular protrusion. Br J Oral Surg 1968;6:64 36. McNeil RW, Proffit WR, White RP. Cephalometric prediction for orthognathic surgery. Angle Orthod 1972;42:154 37. Burstone CJ, James RB, Legan HC. Cephalometric for orthognathic surgery. J Oral Surg 1978;36:269 38. Kumar V, Ludlow JB, Mol A, et al. Comparison of conventional and cone beam CT synthesized cephalograms. Dentomaxillofac Radiol 2007;36:9
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