Resorption af tandsubstans er styret af signalmolekyler fra naboceller i rodoverfladen og pulpa
Tandorganets væv indeholder populationer af celler der hurtigt både kan danne og nedbryde hårdtvæv. Resorption af tandorganets hårdtvæv, både internt og eksternt, opstår som følge af at der i blødtvævene foregår en ophobning af klaster der er specialiserede til at resorbere hårdtvæv: knogle, cement, dentin og emalje. Hvad der har styret denne ophobning af klaster, har hidtil været præget af stor uklarhed, men ny forskning har kastet lys over flere spørgsmål.
Resorption of dental hard tissue is governed by signal molecules from neighbouring cells in the surfac e of the root and the pulp: Recent studies have provided a new concept which elucidate the regulation of clasts during physiologic or pathologic processes in the teeth. A number of these studies have found that OPG, RANK and (s)RANKL plays a pivotal and integrating role during bone remodeling, development of several diseases (27,47,58m59), and a range of situations with resorption of hard dental tissue (22,30). Previous observations indicated that the periodontal ligament and cement forms a barriere which inhibit the formation of clasts and root resorption. It has been suggested that dental trauma may lead to removal of such a barriere and eventually with better opportunities for the clasts to resorb the dental hard tissues (1,23,35-37). These observations are now supported at the molecular level. OPG, RANK and (s)RANKL are fundamental in the regulation of bone resorption and formation, and they are also involved in the regulation of resorptions in dental hard tissues. Recent evidence indicate that the signaling molecules play a central role during eruption and shedding (22,30), during development of tooth resorptions, ankylosis and potential development of infraposition (8,22,60). The discovery of OPG, RANK and (s)RANKL adds new knowledge which integrates clinical observations with basic tissue reactions, a knowledge which potentially can contribute in the development of new treatment modalities (61).