The regenerative potential of oxytalan fibers An experimental study in the monkey

Abstract

Although a number of studies have described the oxytalan fibers as being a natural component of the periodontal ligament, little information exists about the regenerative potential of these connective tissue fibers. The aim of the present study was to examine whether oxytalan fibers have the capacity to reform after regenerative periodontal therapy. Intrabony defects were produced surgically at the mesial aspects of teeth 37, 35, 45, 47 and at the distal aspects of teeth 11, 21, 31, 41 in one monkey (Macaca fascicularis). After 3 months, the defects were exposed using a full-thickness flap procedure. The root surfaces were debrided and subsequently PDGF-growth factors were placed in the defects. 4 of the 8 sites were covered with a bioresorbable membrane before closure of the wound. Post-surgically, antibiotics were given systemically for 1 week, and tooth cleaning was carried out 1x a week during the entire experimental period. After 5 months, the animal was sacrificed and the oral tissues were fixed by perfusion with 10% buffered formalin. Specimens containing the defects and surrounding tissues were dissected free and histological sections were cut in the mesio-distal direction, parallel to the long axes of the teeth. The sections were stained with hematoxylin and eosin or with the oxone-aldehyde-fuchsin-Halmi staining method and subsequently examined in the light and in the electron microscope. The results revealed that new oxytalan fibers oriented mainly in an apico-occlusal direction had developed in the regenerated periodontal ligament. Many of the newly-formed fibers were inserted into the new cementum, thus suggesting a strong relationship between this tissue and the oxytalan fibers. It is concluded that the regenerated periodontal ligament connective tissue formed after surgery contains oxytalan fibers similar to those present in the original tissue. These results demonstrate that oxytalan fibers develop de novo in the newly-formed periodontal ligament.

Pre-clinical Models for Oral and Periodontal Reconstructive Therapies

“…A variety of defect configurations has been surgically created in non-human primate dentitions, including palatal dehiscence (Laurell et al, 2006) and intrabony (Sculean et al, 1997(Sculean et al, , 2002, Class II-III furcation (Ripamonti et al, 2001;Hovey et al, 2006), and fenestration lesions (Sculean et al, 2000a(Sculean et al, , 2001. Fenestration defects typically heal spontaneously, due to the residual periodontal tissues whereby mesenchymal progenitor cells can easily repopulate the defect.…”

“…Moreover, chronic defects closely resemble those in the human situation, with respect to the microbial flora and the inflammatory reaction (Caton et al, 1994;Karatzas et al, 1999). Surgically created periodontal defects have been used to study the impact of GTR or GBR and the application of biologics, including enamel matrix proteins, BMP-2, FGF-2, TGF-β3, and PDGF (Sculean et al, 1997(Sculean et al, , 2000bRipamonti et al, 2001;Takayama et al, 2001;Donos et al, 2003;Teare et al, 2008). Potential endpoint analyses are generally performed between 3 and 6 mos by measurement of the length and/or area of new attachment, cementum, and bone.…”

Effects of Fibrillin Application on Periodontal Ligament Regeneration in Mouse Model of Tooth Replantation

“…Oxytalan fibers exhibit unique features, such as vertically oriented enclosure of the root axis, perpendicular orientation of collagen fibers, closer proximity to the cementum than to the alveolar bone, and frequent insertion into the root cementum 15,16) . We have previously shown that fibrillin 1 and 2 are initially expressed at the surface of the developing root and widely observed in mature human PDL tissue 17) .…”

Efeitos do envelhecimento nos componentes fibroelásticos da junção vésico-uretral de ratos wistar.

“…Esses autores também citam que estas fibras podem ser evidenciadas pelos métodos de coloração da resorcina-fucsina e da aldeído-fucsina após prévia oxidação com oxona, e que as mesmas por apresentarem resistência à hidrólise ácida são denominadas de oxitalânicas e como evidenciado por Sculean et al (1997) Segundo Junqueira e Carneiro (1999) as fibras elásticas maduras são constituídas por uma grande quantidade de elastina e uma proporção muito menor de microfibrilas, sendo a elastina uma glicoproteína estrutural. Greenlee et al (1966) descreve que estas fibras contêm dois componentes morfológicos, onde se observa uma região central ampla ''núcleo" circundada por uma fina camada de fibrilas, cada qual com 100A˚ de diâmetro aproximadamente.…”

“…A análise deste estudo, representado pelas figuras de 10 a 33, demonstra que as fibras elásticas maduras são formadas por componente material amorfo eletrodenso, compacto e abundante (elastina), as fibras elaunínicas por escasso material amorfo (elastina) e componente microtubular em maior quantidade e as oxitalânicas compostas apenas por componente microtubular formando feixes e dispostos paralelamente não estando associados a elastina. (GAWLIK, 1965;GOLDFISCHE et al, 1983), pele (COTTA-PEREIRA et al, 1975), periodonto (FULLMER e LILIE, 1958FULLMER, 1978;SAWADAculean et al, 2006, SCULEAN et al, 1997, ducto deferente (PANIAGUA et al, 1983), cápsula esplênica (SACHETTI, 1996), musculatura lisa (CARVALHO et al, 1997), coração (SOUZA et al, 1996), junção vésico-uretral (AWAD et al, 1976DASS et al, 1999;LÁPIDES, 1958), uretra (BUMP et al, 1988), próstata (KARLINSKI et al, 1976, fáscia transversal iguinal (RODRIGUES, Jr. et al, 1990), pulmão (NIEWOEHNER et al, 1994), colo vesical (ROTHER et al, 1996), neste estudo também confirmamos a distribuição das fibras do sistema elástico na junção vésico-uretral concordando com os achados de Lápides ( Everts et al (1998) ;Fullmer et al, (1974) Gawlik (1965Sakai et al, 1986;Sims et al (1973Sims et al ( , 1975Takagi et al (1989) relataram que as fibras que compõem o sistema elástico são evidenciadas, na microscopia de luz, pelos métodos de coloração hematoxilina férrica (Verhoeff), resorcinafucsina (Weigert) e resorcina-fucsina com prévia oxidação (Weigert-Oxona), corando fibras elásticas maduras, fibras elásticas maduras e elaunínicas, fibras elásticas maduras, elaunínicas e oxitalânicas, respectivamente. Em nosso trabalho, também foi possível identificar e tipificar o sistema elástico, através da microscopia de luz com o uso dessas colorações específicas, em que foi possível realizar a evidenciação das fibras elásticas maduras, elaunínicas e oxitalânicas na JVU, sendo assim observamos que essas fibras estão localizadas em toda a camada muscular da JVU não estando organizadas em feixes, cadeias ou lâminas como aquelas encontradas na pele …”