Abstract

Mandibular advancement is performed in patients routinely by traditional bilateral sagittal split osteotomy (BSSO) or less commonly by distraction osteogenesis (DO). The influence of mandibular advancement on the temporomandibular joint (TMJ) is well recognized but not fully explored. This study involved the direct measurement of synovial fluid hydrostatic pressure (SFHP) in the TMJ after mandibular advancement by either BSSO or DO in two male mature minipigs, Sus scrofa. Titanium pressure transducers were inserted into the right superior temporomandibular joint spaces of the minipigs and the measurements were displayed on an AC/DC amplifier. The first minipig underwent BSSO, which involved immediate mandibular advancement of 14 mm. The pressure measured at the TMJ showed preoperatively slightly subatmospheric values (-50 mm Hg). Postoperatively, these values increased sharply over two days to 220 mm Hg and then increased progressively over a period of four weeks to 310 mm Hg. After which, a decline in pressure was noted. The second minipig underwent DO, which involved slow mandibular advancement of 2 mm per day for a total of 14 mm. Each day the distraction devices were activated and, the pressure measured at the TMJ showed an increase from immediately preactivation (-50 mm Hg to 10 mm Hg) to immediately postactivation (-10 mm Hg to 150 mm Hg) measurements. Furthermore, postactivation pressures declined to near baseline values (-50 mm Hg) by the time of the next activation of the distraction devices the following day. The pressure transmitted to the condyle by slow mandibular advancement via distraction osteogenesis was short lived and smaller compared to that transmitted by immediate mandibular advancement. In both mandibular advancement cases slightly lower values were recorded with mouth open compared to closed mouth. NewTom volumetric scans were taken after sacrificing the minipig and, the position of the transducer and the extent of the distraction were verified.

In conclusion, we developed an animal model and a technique to measure directly synovial fluid hydrostatic pressure in the TMJ after mandibular advancement procedures. This allowed evaluation and comparison of different methods for mandibular advancement namely, traditional orthognathic surgery and distraction osteogenesis.

LLU Discipline

Orthodontics and Dentofacial Orthopedics

Department

Orthodontics and Dentofacial Orthopedics

School

Graduate School

First Advisor

Alan S. Herford

Second Advisor

Philip J. Boyne

Third Advisor

Joseph M. Caruso

Fourth Advisor

Jay Kim

Fifth Advisor

V. Leroy Leggitt

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

2003

Date (Title Page)

9-2003

Language

English

Library of Congress/MESH Subject Headings

Temporomandibular Joint Disorders; Synovial Fluid; Osteotomy; Mandible

Type

Thesis

Page Count

xii; 42

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives

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