The conclusions indicated that the facial concavity, in regard to the relationship of the hard and soft tissue chin to the upper face, was decreased by this surgical ...
10.5005/jp-journals-10021-1042
ORIGINAL ARTICLE Manish Goyal et al
Dentoskeletal and Soft Tissue Profile Changes Associated with Mandibular Setback Osteotomy: A Cephalometric Study 1
Manish Goyal, 2Akshay Shetty, 3Rajesh Reddy, 4Ramanna Reddy, 5Mukesh Kumar
ABSTRACT The aims of the present cephalometric study1 were (1) to describe the interrelationships of the soft tissue and dentoskeletal profiles following total mandibular setback osteotomies and (2) to detect whether there were cephalometric variables that could contribute to an accurate prediction of the surgical effect on the soft tissue profile. Pretreatment, presurgical and postsurgical lateral cephalograms of eight adult patients who had been treated successfully by preadjusted edgewise appliance for presurgical decompensation were obtained. Bilateral sagittal split osteotomy for mandibular setback procedure was carried out under the supervision of a single surgeon. The conclusions indicated that the facial concavity, in regard to the relationship of the hard and soft tissue chin to the upper face, was decreased by this surgical procedure; facial esthetics was improved. The mandible assumed a more normal relationship to the upper denture base. The least amount of change of the soft tissue profile was exhibited by the upper lip and maxillary sulcus of the upper lip. The greatest amount of change of the soft tissue profile was exhibited by the lower lip, the mandibular sulcus of the lower lip and the soft tissue chin. Keywords: Mandibular prognathism, Maxillary advancement, Dentoosseous, Mandibular setback osteotomies, Cephalometric variables, Cephalograms, Bilateral sagittal split osteotomy. How to cite this article: Goyal M, Shetty A, Reddy R, Reddy R, Kumar M. Dentoskeletal and Soft Tissue Profile Changes Associated with Mandibular Setback Osteotomy: A Cephalometric Study. J Ind Orthod Soc 2011;45(4):232-236.
INTRODUCTION 2
The facial deformity caused by mandibular prognathism has long been of great mutual interest to the orthodontist and the oral surgeon. The deformity of the lower jaw is readily expressed as a profile disfigurement, since the soft tissues of the face depend on the lower jaw for much of their contour. The dental literature is replete with various surgical techniques for the correction of mandibular prognathism.1 The consequences of surgery on facial appearance are of great importance. Therefore an accurate prediction of the postoperative facial profile comprises an essential and integral
part of the diagnosis and treatment planning in orthognathic procedures. AIMS AND OBJECTIVES The aims of the present cephalometric study were: 1. To describe the interrelationships of the soft tissue and dentoskeletal profiles after total mandibular setback osteotomies.3 2. To detect whether there were any cephalometric variables that could contribute to an accurate prediction of the surgical effect on the soft tissue profile. MATERIALS AND METHODS
1-5
Professor
1
Department of Orthodontics, DBDC Dental College, Muktsar Punjab, India
2
Department of Orthodontics, RV Dental College, Bengaluru Karnataka, India 3
Department of Orthodontics, Sri Sai Dental College, Vikarabad Andhra Pradesh, India 4 Department of Orthodontics, SVS Dental College, Mahbubnagar Andhra Pradesh, India 5 Department of Orthodontics, Rungta Dental College, Bhilai Chhattisgarh, India
Corresponding Author: Manish Goyal, Professor, Department of Orthodontics, H. No 197-198, Pocket 12, Sector 24, Rohini-85, New Delhi India, e-mail: manishortho@ yahoo.com
Pretreatment (T), presurgical (T1) and postsurgical (T2) lateral cephalograms of eight adult patients (4 males and 4 females) who had been treated by preadjusted edgewise appliance for presurgical decompensation with or without extractions were obtained. Upper first premolars and lower second premolars were extracted for presurgical decompensation. The age group of these patients ranged from 17 to 25 years, with a mean age of 21 years. Postsurgical cephalograms were taken 2 months following surgery. Bilateral sagittal split osteotomy for mandibular setback procedure was carried out on these patients under the supervision of a single surgeon. Criteria for Selection of Patients
Received on: 21/2/11 Accepted after Revision: 9/10/11
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The primary selection criteria were as follows: 1. Patient was a nongrowing adult. JAYPEE
JIOS Dentoskeletal and Soft Tissue Profile Changes Associated with Mandibular Setback Osteotomy: A Cephalometric Study
2. The age group of these patients ranged from 17 to 25 years with a mean age of 21 years. 3. Patient had a natural dentition supporting the lips. 4. Patient demonstrated a severe Class III skeletal malocclusion with an ANB of –1° to –5° and prognathic mandible for which surgical intervention was necessary. 5. Mandibular setback procedure was carried out by bilateral sagittal split osteotomy technique. Analysis of Lateral Cephalograms Lateral cephalograms were taken in occlusion under standardized conditions with a cephalostat. Among the various surgical cephalometric analyses for estimating the amount of hard and soft tissue changes, the Legan Burstone, Steiner’s, McNamara, Rickett’s, Holdaway and Rakosi Jarabak analysis were employed in this study (Figs 3 to 9). These analyses include certain angular and linear measurements for both hard and soft tissues, which were easily applicable for the study. Materials Used (Fig. 1) •
Standardized pretreatment, presurgical and postsurgical cephalograms
Fig. 1: Armamentarium used in the study
• • • • • • •
A 0.3 mm acetate tracing paper A 0.3 mm lead pencil Geometry box (scale, protractor, setsquares, eraser, sharpener) Scotch tapes Tracing board Black, green and red pilot pens Scissors and calculator.
RESULTS The present study consists of eight patients who were in the age group of 17 to 25 years with a mean age of 21 years. Lateral cephalograms; pretreatment, presurgical and postsurgical were taken in habitual occlusion. The surgical technique performed was bilateral sagittal split osteotomy for mandibular setback with rigid internal fixation by screws. The magnitude of setback was between 4 and 6 mm. Pretreatment and presurgical cephalograms 6 were superimposed over postsurgical cephalogram with Ba-Na line registered at CC-point (Fig. 2) for the evaluation of the dentoskeletal and soft tissue changes. Hard tissue and soft tissue cephalometric measurements of pretreatment, presurgical and posttreatment lateral
Fig. 2: Template of superimposition
Fig. 3: Pretreatment, presurgical, posttreatment photographs
The Journal of Indian Orthodontic Society, October-December 2011;45(4):232-236
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Fig. 4: Superimposition: Basion-nasion at CC point
Fig. 7: Hard tissue analysis (linear parameters)
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Fig. 5: Dental analysis (angular and linear parameters)
Fig. 8: Soft tissue analysis (angular parameters)
Fig. 6: Hard tissue analysis (angular parameters)
Fig. 9: Soft tissue analysis (linear parameters)
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JIOS Dentoskeletal and Soft Tissue Profile Changes Associated with Mandibular Setback Osteotomy: A Cephalometric Study Table 1: Skeletal measurements angular (deg) Measurement
T
T1
T2
T1-T
T2-T
Diff. 1. 2. 3. 4. 5.
SNB ANB N-A/Pg-A MP-HP N-Pg/FH
85.00 ± 5.55 85.25 ± 5.65 – 2.63 ± 1.19 – 2.50 ± 1.41 – 3.63 ± 2.07 – 4.38 ± 1.85 25.13 ± 3.18 25.13 ± 3.18 89.75 ± 3.45 89.25 ± 3.20
p*
80.63 ± 4.53 0.25 ± 0.46 2.13 ± 0.99 0.13 ± 0.35 – 1.13 ± 1.36 – 0.75 ± 1.16 25.88 ± 4.49 0.00 ± 0.00 85.13 ± 2.85 – 0.50 ± 0.53
T2-T1
Diff.
p
Diff.
p
0.17 NS – 4.38 ± 1.69 < 0.001 HS – 4.63 ± 1.85 < 0.001 HS 0.35 NS 4.75 ± 0.71 < 0.001 HS 4.63 ± 1.06 < 0.001 HS 0.11 NS 2.50 ± 2.62 0.03 S 3.25 ± 2.19 < 0.01 HS 1.00 NS 0.75 ± 1.75 0.26 NS 0.75 ± 1.75 0.26 NS 0.03 S – 4.63 ± 2.20 < 0.001 – 4.13 ± 1.89 < .001 HS
Paired t-test: p < 0.05, p < 0.01 significant (S); p < 0.001 highly significant (HS); p > 0.05 not significant (NS); *p: Probability of presurgical and pretreatment differences of dentoskeletal and soft tissue changes Table 2: Skeletal measurements linear (mm) Measurement
T
T1
T2
T1-T
T2-T
Diff.
p*
T2-T1
Diff.
p
Diff.
p
1. N-B (11 HP)
3.13 ± 5.96
3.88 ± 6.24
–1.25 ± 5.06
0.75 ± 0.46
