Umeå University's logo

umu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • apa-6th-edition.csl
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Temporomandibular joint disk displacement and subsequent adverse mandibular growth: a radiographic, histologic and biomolecular experimental study
Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Radiology.
2008 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The mandibular condyles represent important growth sites within the facial skeleton. Condylar growth is not a pacemaker of mandibular development, but it provides regional adaptive growth that is of considerable clinical significance, as the condyle’s upward and backward growth movement regulates the anteriorly and inferiorly directed displacement of the mandible as a whole.

Orthopedic problems of the temporomandibular joint (TMJ), such as displacement of the TMJ disk, are common in the adolescent population. Clinical studies of mandibular asymmetry and mandibular retrognathia in adults as well as in children and adolescents, have reported an association with coexisting non-reducing displacement of the TMJ disk without identifying the cause and effect. Through experimental studies causality has been established, and unilateral affliction during growth has been shown to retard ipsilateral mandibular development with facial asymmetry as the sequel. It was hypothesized that bilateral non-reducing TMJ disk displacement during growth would impair mandibular development bilaterally, resulting in mandibular retrognathia. TMJ disk displacement has repeatedly been demonstrated to induce histological reactions of the condylar cartilage. An additional assumption was therefore that a non-deranged TMJ disk function is crucial for the maintenance of the growing condyle’s biophysical environment, and that a connection ought to exist between the amount of condylar cartilage changes caused by TMJ disk displacement and the amount of subsequent adverse mandibular growth. It was also hypothesized that non-reducing displacement of the TMJ disk in growing individuals would result in qualitative and quantitative changes of the condylar subchondral bone.

An improved experimental cephalometric method was developed in order to optimize the reliability of longitudinal radiographic evaluation of fast growing small animals. Bilateral non-reducing TMJ disk displacement was surgically created in ten growing New Zealand White rabbits, with ten additional rabbits serving as a sham operated control group. The amount and direction of craniofacial growth was followed over time in serial cephalograms, aided by tantalum implants in the jaws. The study period was chosen to correspond to childhood and adolescence in man. The assessed growth of each side of the mandible was correlated to the histological feature of ipsilateral condylar cartilage at the end of the growth period. The amount and composition of subchondral bone from three regions of interest in the condyle, and the expression of local growth factors in the adjacent condylar cartilage was evaluated.

The results verified that bilateral non-reducing TMJ disk displacement retarded mandibular growth bilaterally; the extent corresponding to mandibular retrognathia in man. Displacement of the TMJ disk during the growth period induced condylar cartilage adaptive reactions that were associated with both an adverse amount and direction of mandibular growth, manifesting in a retrognathic mandibular growth pattern. Growth impairment fluctuated over time, with the most striking retardation occurring during periods of increased general growth, implying a local growth reduction explicitly counteracting general hormonal growth acceleration. A significant decrease of the total amount of subchondral bone, in spite of a general increase of new bone formation in the experimental condyles, pointed to a reparative compensation for an extensive resorption of subchondral bone due to displacement of the TMJ disk, but not to the extent that normal growth would be maintained. These results constitute an explanation for the adverse mandibular development following non-reducing TMJ disk displacement in growing individuals.

This project has shown that non-reducing displacement of the TMJ disk during growth has significant consequences on facial development. The findings strongly advocate early and accurate diagnosis and treatment of TMJ disk displacement in the adolescent population, thereby presumably reducing the need for future orthodontic and surgical craniofacial corrective therapy. The results furthermore enhance the need for full appraisal of TMJ disk function in the adolescent population during orthodontic functional therapy, as the condylar cartilage and subchondral bone reactions to a concomitantly displaced non-reducing TMJ disk must be expected to interfere with the intended growth stimulating treatment. The findings of intact articular layers in spite of gross histological and morphological soft and hard tissue changes as a sequel to TMJ disk displacement in growing individuals, implicate a clinical risk of false positive radiographic diagnosis of degenerative changes of the TMJ in children and adolescents.

Place, publisher, year, edition, pages
Umeå: Oral diagnostisk radiologi , 2008. , p. 58
Series
Umeå University odontological dissertations, ISSN 0345-7532 ; 103
Keywords [en]
adolescence, adverse growth, condylar cartilage, subchondral bone, TMJ
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
URN: urn:nbn:se:umu:diva-1624ISBN: 978-91-7264-523-3 (print)OAI: oai:DiVA.org:umu-1624DiVA, id: diva2:141588
Public defence
2008-05-09, Sal B, 1 D, Tandläkarhögskolan, Umeå, 09:00 (English)
Opponent
Supervisors
Available from: 2008-04-28 Created: 2008-04-28 Last updated: 2018-06-09Bibliographically approved
List of papers
1. Titanium screw implants in optimization of radiographic evaluation of facial growth in longitudinal Animal studies
Open this publication in new window or tab >>Titanium screw implants in optimization of radiographic evaluation of facial growth in longitudinal Animal studies
2004 (English)In: The angle orthodontist, ISSN 0003-3219, Vol. 74, no 5, p. 610-617Article in journal (Refereed) Published
Identifiers
urn:nbn:se:umu:diva-3112 (URN)
Available from: 2008-04-28 Created: 2008-04-28 Last updated: 2018-06-09Bibliographically approved
2. Bilateral TMJ disk displacement induces mandibular retrognathia
Open this publication in new window or tab >>Bilateral TMJ disk displacement induces mandibular retrognathia
2006 (English)In: Journal of dental research, ISSN 0022-0345, Vol. 85, no 12, p. 1118-1123Article in journal (Refereed) Published
Identifiers
urn:nbn:se:umu:diva-3113 (URN)
Available from: 2008-04-28 Created: 2008-04-28 Last updated: 2018-06-09Bibliographically approved
3. Cartilage changes link retrognathic growth to TMJ disk displacement
Open this publication in new window or tab >>Cartilage changes link retrognathic growth to TMJ disk displacement
(English)Manuscript (preprint) (Other academic)
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:umu:diva-3114 (URN)
Available from: 2008-04-28 Created: 2008-04-28 Last updated: 2018-06-09Bibliographically approved
4. Subchondral bone loss explains retrognathic mandibular growth at TMJ disk displacement
Open this publication in new window or tab >>Subchondral bone loss explains retrognathic mandibular growth at TMJ disk displacement
(English)Manuscript (preprint) (Other (popular science, discussion, etc.))
Identifiers
urn:nbn:se:umu:diva-3115 (URN)
Available from: 2008-04-28 Created: 2008-04-28 Last updated: 2018-06-09Bibliographically approved

Open Access in DiVA

fulltext(2237 kB)4545 downloads
File information
File name FULLTEXT01.pdfFile size 2237 kBChecksum MD5
7829dcec25816e2093bbdc44158c1c2d1436a5028e939c32dae82259ba4f6bd3f1721c4d
Type fulltextMimetype application/pdf

Authority records

Bryndahl, Fredrik

Search in DiVA

By author/editor
Bryndahl, Fredrik
By organisation
Oral and Maxillofacial Radiology
Radiology, Nuclear Medicine and Medical Imaging

Search outside of DiVA

GoogleGoogle Scholar
Total: 4545 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 2644 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • apa-6th-edition.csl
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf