Application of botulinum toxin in maxillofacial field: part I. Bruxism and square jaw

Abstract

The application of botulinum in oral and maxillofacial surgery begins in 1982, where Jan Carruthers started using it for reducing the muscle mass and smoothing the skin, and since then it has been used for cosmetic purposes. In Korea, it is already being used by various specialties including dentistry (oral and maxillofacial surgery, oral medicine), plastic surgery, dermatology, ophthalmology, general surgery, and orthopedic surgery, etc. Each specialty approaches to Botox with its own medical indications. In this article, we will discuss the maxillofacial application of botulinum toxin, which includes theoretical and practical aspects of such as bruxism and square jaw.

Keywords: Botulinum toxin; Bruxism; Clinical application; Maxillofacial field; Square jaw.

Conflict of interest statement

Competing interestsThe authors declare that they have no competing interests.

© The Author(s). 2019.

Figures

Fig. 1

Injecting 2.5 cc saline into botulinum toxin vial

Fig. 2

1 cc insulin syringe

Fig. 3

Perform botulinum toxin injection after understanding the overall anatomical structures for facial muscles. In particular, carefully look for orientation of frontalis, procerus, and masseteric muscle

Fig. 4

A protocol used for forehead wrinkles, eye wrinkles, etc. A standard dose is estimated based on the dose of Botox and BTXA (formula by Carruthers) [12, 13]

Fig. 5

When injecting botulinum toxin in the forehead wrinkles, noted that the injecting point should be 1.5–2 cm far away from the eyebrows

Fig. 6.

In the case of a square jaw patient, inject the toxin 1.5–2 cm far away from the margin of the mandible. Inject the toxin into the center of the triangle formed with a line joining corner of the mouth and tragus of the ear with a line joining the angle of the mandible and corner of the mouth

Fig. 7

Picture in the left is before the injection, picture in the middle is after 6 months of injection, and picture in the right is after 12 months of injection. The therapeutic effect was greatest at 6th month, and even though there was a bit of regression phenomenon at 12 month compared with the initial picture one can able to continuously observe contraction of the masseteric muscle. It is possible to determine the timing of the second injection.

Fig. 8

Variation in percentage reduction in muscle mass over time. This graph demonstrates the variation in percentage reduction in muscle mass overtime. According to the result of ultrasonic testing, the extent of reduction in muscle mass began after the injection, from third week, and persisted up to 6 months. It is evident that the second injection should be performed within 3–6 months [14]

Fig. 9

For an initial assessment of bruxism and square jaw, with tests such as sonography, skull PA, and panorama as seen above, one can examine the degree of contraction or hypertrophy of masseteric muscle of a patient with bruxism or square jaw, and able to identify the temporomandibular joint disorder, determine occlusal relationships, and diagnose pathological diseases. An average of 10 mm or more is determined as masseteric hypertrophy

Fig. 10

Areas colored with blue represent temporal and masseter muscles, black point represent injection point, and approximately 10 BU is injected to each injection point. Triangular area colored with yellowish green represent the landmark line of masseter muscle hypertrophy section

Fig. 11

Brand names for botulinum toxin A include Dysport, BTXA, Botox, etc. The drugs differ from each other in their unit and possess different methods of injection depending on their method of dilution

Fig. 12

A patient who had chronic migraine, bruxism, benign masseteric hypertrophy. Pre-injection of BTX (left), after 1 month clinical photo (right)

Fig. 13

Diagnosing method for square jaw: sonograph. With the help of Panorama, skull PA, and sonograph of masseter muscle, you can identify the skeletal portion and patterns of muscle hypertrophy, and able to decide which one to use: surgical intervention or botulinum toxin injection

Fig. 14

Type I. muscular type. Hypertrophy of masseteric muscles is prominent, improvement is expected after botulinum toxin A injection

Fig. 15

Type II. Skeletal lateral projection type. Picture in the left is pre-operative 3D model, picture in the right is the post-operative picture directly performed on 3D. Angle reduction is noticed

Fig. 16

Type III. Combination type. Patient with outwardly projecting mandibular angle and muscular hypertrophy is observed