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EVALUATION OF SOFT TISSUE CHANGES FOLLOWING LEFORT-I SURGERY USING SOFT TISSUE MARKERS: A SIX MONTH PROSPECTIVE STUDY

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INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com

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INTRODUCTION The two prime objectives of orthognathic surgery are normal occlusion and improved facial esthetics. There are great variations in the amount and distribution of the soft tissue elements soft tissues exhibit more consistent changes, while the unattached tissues show less consistent change. Even an excellent osteotomy of maxilla and mandible may create an unpleasant effect because of changes in soft tissues which is difficult to control. www.indiandentalacademy.com


AIM To study the soft tissue changes in patient’s who had undergone Lefort 1 osteotomy by utilizing Arnett and bregman’s soft tissue markers.

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Objectives To determine the soft tissue structural changes of the middle third of face. To determine the facial length changes. To determine the antero – posterior measurements of soft tissues overlying the hard tissue landmarks.

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Materials and methods Total no. of patients

- 8.

ď Ž

Males

- 5.

ď Ž

Females

- 3.

Patients who required Lefort I were taken for the study.

The maxilla was always kept in one piece. When indicated, considerable effort was made to prevent undesirable nasal changes, including resection of the anterior nasal spine, flattening of the pyriform rim, and reduction of nasal septum.

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Lateral cephalograms were taken one week preoperatively and 1, 3 and 6 months post operatively to evaluate the soft tissue changes as a result of surgery. Persons for whom additional procedures were indicated except Genioplasty. persons with underlying systemic disease and persons with cleft Deformities and syndromes were excluded from the study. www.indiandentalacademy.com


Soft tissue markers For soft tissue cephalometric analysis, metallic markers were placed on the right side of face to mark the key mid face structures. The key structures are the orbital rim, cheek bone, alar- base contour and sub- pupil which indicate the anero – posterior position of maxilla.

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Soft tissue markers

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ORBITAL MARKER The Orbital marker is placed directly over the osseous orbital rim and directly under the pupil with the eye in the straight gaze.

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CHEEK BONE MARKER The Cheek bone required two perspectives. First, examined from 他 view, the right malar height of contour was marked with ink. Then, with the examiner standing directly in front of the patient a metal bead was placed at the intersection of right malar height of contour ink mark and a vertical line through the outer canthus. www.indiandentalacademy.com


ALAR BASE MARKER A Metallic bead was placed at the deepest depression at the alar base of the nose.

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SUB – PUPIL MARKER The Sub – pupil marker was placed one half the vertical distance between the alar – base marker and the orbital rim marker directly below the straight ahead gaze of the pupil.

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Lateral ceph with markers

1

2

3 4

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METHODOLOGY With the marked mid – face structures using markers, lateral cephalograms were obtained with the patient positioned in the lateral head position, seated condyle and with passive lips.

All tracings were drawn by a single operator. Each tracing of a radiograph was made on 0.003 inch acetate paper with a 0.5mm pencil. www.indiandentalacademy.com


PRE OPERATIVE

LATERAL PROFILE

FRONTAL PROFILE

LATERAL CEPHALOGRAM

CEPHALOGRAM TRACING

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1 MONTH POST OPERATIVE

FRONTAL PROFILE

LATERAL CEPHALOGRAM

LATERAL PROFILE

CEPHALOGRAM TRACING

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3 MONTH POST OPERATIVE

LATERAL PROFILE

FRONTAL PROFILE

LATERAL CEPHALOGRAM

CEPHALOGRAM TRACING

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6 MONTH POST OPERATIVE

FRONTAL PROFILE

LATERAL PROFILE

LATERAL CEPHALOGRAM CEPHALOGRAM TRACING www.indiandentalacademy.com


LATERAL CEPH WITH SUPERIMPOSITION

Black

-

Pre-operative

Blue

-

1 Month Post-operative

Red

-

3 Month Post-operative

Green

-

6 Month Post-operative

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The tracings included the anterior cranial base, the soft tissue profile, the key mid face structures marked with metallic beads and the outlines of maxilla and mandible. A reference system was developed to measure the displacement of the points considered in both the X and Y directions. www.indiandentalacademy.com


The X-axis of this coordinate system consisted of the constructed Frankfort horizontal (a line 70 below the S-N line). The Y-axis was established by drawing a line perpendicular to the X-axis with it’s origin at sella. For each cephalogram 2 hard tissue landmarks and 15 soft tissue landmarks were identified. www.indiandentalacademy.com


HARD TISSUE LANDMARKS 1. MAXILLARY INCISAL EXPOSURE – It is the vertical distance measured between the upper lip inferior and the incisal tip of maxillary central incisor. 2. MAXILLARY HEIGHT – It is the distance from Sn to the maxillary incisal tip.

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Maxillary height & Incisal exposure

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SOFT TISSUE LANDMARKS 1. UPPER LIP THICKNESS – It is the distance measured from the upper lip inside to the upper lip anterior. 2. NASOLABIAL ANGLE – It is formed by the intersection of a columella tangent and an upper lip tangent. 3. UPPER LIP LENGTH – It is the distance measured from Sn to the upper lip inferior. 4. INTERLABIAL GAP – It is the distance measured from the upper lip inferior to the lower lip superior. www.indiandentalacademy.com


SOFT TISSUE STRUCTURES

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NASOLABIAL ANGLE


MIDFACE LANDMARKS Orbital rim Cheek bone Subpupil Alar base Nasal projection Subnasal ‘A’ point Upper lip antreior Maxillary incisal tip Soft tissue ‘A’ point. www.indiandentalacademy.com


Standardisation of Radiograph Steps to correct the magnification of the lateral cephalogram were not considered necessary because absolute measurements were made and all cephalograms were taken at a fixed object – source distance. Ten tracings were selected at random. These were selected to estimate the accuracy of the linear measurements, which did not exceed less than or more than 0.6mm. www.indiandentalacademy.com


Result

Table 1 : Midface soft tissue structures PRE OP 1 MONTH

PRE OP 3 MONTH

PRE OP - 6 MONTH

1 MONTH - 3 MONTH

1MONTH - 6 MONTH

3 MONTH 6 MONTH

X

Y

X

Y

X

Y

X

Y

X

Y

X

Y

Orbital rim

NS

NS

NS

NS

NS

NS

NS

NS

NS

NS

NS

NS

Cheek Bone

NS

NS

NS

NS

NS

NS

S

NS

NS

NS

NS

NS

Sub Pupil

S

NS

S

NS

S

NS

NS

NS

S

NS

NS

NS

Alar Base

S

NS

NS

NS

NS

NS

S

NS

S

S

NS

NS

Nasal projection

S

NS

NS

NS

NS

NS

NS

NS

NS

NS

NS

NS

Sub Nasal

S

NS

NS

NS

S

NS

S

NS

S

NS

NS

NS

A' Point

NS

S

NS

S

NS

S

NS

NS

NS

S

NS

NS

Upper Lip Anterior

NS

NS

NS

NS

NS

NS

NS

NS

S

NS

S

NS

Maxillary Incsal Tip

NS

S

NS

S

NS

S

NS

NS

NS

NS

NS

NS

S

S

NS

NS

NS

NS

S

NS

S

NS

S

NS

Soft Tissue 'A' Point S - Significant;

NS - Non Significant; P Value <0.05. www.indiandentalacademy.com


Table 2 : Hard Tissue Structures

PRE OP 1 MONTH

PRE OP 3 MONTH

PRE OP - 6 MONTH

1 MONTH 3 MONTH

1MONTH 6 MONTH

3 MONTH -6 MONTH

Maxillary Incisal EXP

S

S

S

NS

NS

S

Maxillary Height

S

S

S

NS

NS

NS

PRE OP 1 MONTH

PRE OP 3 MONTH

PRE OP – 6 MONTH

1 MONTH 3 MONTH

1MONTH 6 MONTH

3 MONTH 6 MONTH

NS

NS

S

S

S

NS

Nasolabial Angle

S

NS

NS

S

S

S

Upper lip Angle

S

S

S

NS

NS

NS

Upper lip Length

NS

NS

NS

NS

NS

NS

Inner Labial Gap

S

S

S

NS

NS

NS

Table 3 : Soft tissue structures

Upper Lip Thickness

S - Significant;

NS - Non Significant; P Value <0.05.

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Discussion Prediction of soft tissue response to surgical correction of maxillary deformities is more uncertain than that of mandible. The nose, lips and the mid face are subjected to dimensional changes subsequent to maxillary surgeries. Despite many methods that have been introduced for objective evaluation of the hard and soft tissue profile, none of them is totally satisfactory because they aim at making the face conform to a specific predetermined standard. www.indiandentalacademy.com


In this study, a novel approach of assessing the soft tissue changes following Le Fort I surgery was carried out. In a total number of six patients for whom Le Fort I impaction with superior repositioning was done, the mean ,standard deviation, level of significance with mean change was calculated.

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HORIZONTAL HARD AND SOFT TISSUE CHANGES ď Ž

The Orbital marker did not show any statistical change at any time interval either in the horizontal or vertical direction. This is attributed to the location of the marker away from the area of surgical exposure.

ď Ž

The Cheek bone was displaced horizontally by 2 mm from preop to 1 month post-op. This is due to the edema in mid face which reduced within the six month period.

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ď Ž

The Sub- pupil in the same way showed significant changes in the horizontal direction between the pre-op and the 1, 3, 6 month post-op

ď Ž

The horizontal values decreased over a period of time between 1 month to 3 month post-op and from 3 month to 6 month postop.

ď Ž

This aptly agrees with the early literature that many of the soft tissue characteristics return to their pre-operative measurements in the long term www.indiandentalacademy.com


ď Ž

The changes in the Alar base were similar in which their was an increase in the horizontal direction in the first and third post-op month after which the changes came back to the original pre-op values at the end of sixth post-op month.

ď Ž

The nasal projection along the horizontal axis was increased by 3 mm between pre-op and the first post-op month. The horizontal movement of the subnasal in the first and third postop month came back to the pre-op values at the sixth post â&#x20AC;&#x201C;op month and so remained stable. www.indiandentalacademy.com


‘Upper lip anterior’ showed significant changes by a posterior movement of -2.3mm and -0.8 mm in the third and sixth post-op month. This reduction is due to the postero-superior positioning of the maxilla by Le Fort I osteotomy.

The Soft tissue ‘A’ point showed significant increase at the first post-op month which reduced over the next three month and at the sixth post-op month the values were quite similar to the preoperative values. www.indiandentalacademy.com


VERTICAL HARD AND SOFT TISSUE CHANGES 

The ‘A’ Point showed significant changes of 8 mm reduction along the vertical direction which is due to the superior repositioning of the maxilla which agrees with the earlier literature that ‘A’ Point showed the greatest amount of changes in the study.

Maxillary incisal tip demonstrated a 6mm reduction along the ‘y’ axis which is constant from the third post –op month. www.indiandentalacademy.com


Soft tissue ‘A’ Point showed a decrease of 2mm which is the adaptive changes of the upper lip to the underlying hard tissue. The maxillary Incisal Exposure showed the most significant change by a reduction of 8 mm which is the main ideal of Le Fort I surgery in which the maxilla is repositioned superiorly.

The maxillary Height showed significant change by a reduction 4mm uniformly between the pre-op and 1, 3 and 6 month postoperatively. This ratio of maxillary soft to hard tissue is therefore 1:2 which very well agrees with earlier literature. www.indiandentalacademy.com


ď Ž

The Upper Lip Thickness showed an initial increase in thickness in the first month post-op which reduced significantly by the third and sixth post-operative months. This very well correlates with the earlier literature in which a reduction of 1 â&#x20AC;&#x201C; 2mm is noted.

ď Ž

The Nasolabial angle showed significant changes by an immediate post- operative change of + 160 which reduced in the third and sixth month to +60 which agrees with the earlier literature that a mild increase in the nasolabial angle following Le Fort I surger www.indiandentalacademy.com


The Upper Lip Angle showed a decrease of – 100 which remained stable until the sixth post-operative month. The upper lip angle has so far not been studied in any of the earlier literature and that it shows a significant change following Le Fort I surgery is quite evident in this study.

The Interlabial gap showed a decrease of – 8.7 mm in which the interlabial gap reduced from 10.3 to 1.6mm. www.indiandentalacademy.com


CONCLUSION The result shows: 

The Hard Tissue ‘A’ Point showed the greatest change of 8 mm in the vertical direction due to Le Fort I impaction.

Maxillary incisal exposure was significantly reduced by 7mm and so also the maxillary height in the vertical direction.

The Upper Lip Thickness showed a reduction of 2 mm postoperatively. The Lip Length was not affected due to change in the movement of maxilla.

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In maxillary Advancement, the hard tissue ‘A’ point and the maxillary height showed significant increase of 7 mm.

The Upper Lip Anterior showed a decrease of 3mm along the horizontal direction which stabilized in the third post-operative month. In the vertical direction it was increased by 4mm and remained stable after the third post-operative month.

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