 Hello everyone, welcome back to another session in dentistry MO. So today we have a discussion about the abutment in FVD. So what are the criteria we need to look into when selecting an abutment. So as per GPT the abutment can be defined as a tooth or a portion of a tooth or that portion of an implant which is used for the support of a fixed or removable processes. So this abutment role is very crucial in accepting the load of FVD because if something happens to the abutment, if it is not able to withstand the occlusion force, the FVD will be failed. So there are many factors which determines the failure of an FVD with regard to abutment. So we have some 5 to 6 major factors or major criteria to select an abutment. The first one is the location, position and condition of the tooth. So the characteristics of the preferred abutment that are teeth adjacent to edgeless spaces and teeth with grossly decayed crowns that can be restored with a full veneer crown. Then modifications like double core or pin retained amalgam restorations, they needed to restore crown morphology in grossly destructed teeth. Double teeth are preferred, though endodontic teeth can be used, pulp cap teeth cannot be used as they are always under risk of RCT. So these teeth can be selected for an abutment in FVD that are the teeth which is near to the edgeless space, teeth with grossly decayed crowns that can be restored with a full veneer crown or double core or pin retained amalgam restorations which can be needed to restore crown morphology in grossly destructed teeth, mostly vital teeth are preferred, still we can go for teeth with root canal therapy but never use a tooth with pulp capped because they are always under the risk of root canal treatment. Next factor is crown root ratio. So it is the ratio between the length of the crown and length of the root and it should always be less than 1, that is the length of the root should be greater than the length of the crown. So the length of the crown indicates the length of the tooth structure above the crest of the arvela bone, you can see the picture here. So ideally the crown ratio should be 2 to 3, so length of the crown, 2 length of the root is 3 but ratio up to 1 is to 1, that is the equal length of crown and root is acceptable. So that is the crown root ratio. Next is root configuration. In root configuration the forces acting on tooth are transferred to supporting bone through the root, that is how it happens. So the shape of the root determines the ability of the abutment to transfer these masticatory forces to the supporting bone. So roots with greater labiolingual width are preferred or roots with irregular curvature are preferred rather than the straight one because it can withstand more forces in more directions, that is oblique direction of force and apical, I mean the forces which is acting through the long axis of tooth. So always curved roots or the roots with more labiolingual or the buckolingual with this preferred or teeth with longer roots serve as better abutment rather than the shorter roots. So canines is a better abutment rather than the lateral incisor and tooth with conical roots can be used for short span fixed partial denture. So that was about root configuration. Now we have the root support, the fourth one is root support. In root support the supporting alveolar bone should be healthy without any periapical or periodontal problems. So it should have good trapecular architecture and no which should not show any sign of bone defects or bone loss. So the IOPA should be used to evaluate the bone architecture before we are planning it as an abutment. So this alveolar bone support is one of the most important factors that aid to evaluate an abutment. And next we have the periodontal ligament area. So it can be used as a measure of scale to determine the potency of the abutment. So there is something known as antizlo, antizlo. So antizlo before that there was Thillman who stated that two abutment teeth could support two pontics. So this came before Anti. So Thillman stated two abutment teeth, two abutment teeth could support two pontics. But later Antiput forward this law says that the sum of the perisemental areas of the abutment teeth should be equal to or greater than the two to be replaced. So it is a sum of the perisemental area of the abutment teeth. So if you are replacing three teeth and the perisemental area of these three teeth what we are planning for the abutment should be greater. So this law is simple. We need more perisemental area for the abutment teeth than the teeth to be replaced. So the periodontal area of abutment should be calculated and if it is not sufficient, if it is not reaching with respect to the teeth to be replaced we need to take additional support as secondary abutment. So we need to have more perisemental area for the abutment than the teeth to be replaced that is antizlo. Then lastly the assessment of pulpal health. So usually unrestrode abutments are preferred rather than androendically treated or pulpal inflamed which went for any restoration such tooth should be avoided. So if caries is present the regular preparation can be done. If the caries solutions are large they should be scooped out and can be used for additional retention rather than the primary retention and if the abutment tooth has a caries solution with pulpal involvement where the RCD is advised such abutment should be avoided. So that was all about the abutment selection in fixed partial dentures or the criteria we need to think about before planning abutment in FPD that are the location position of the condition of the tooth where to be placed what tooth to be kept as abutment. Then the crown root ratio ideal it is 2 is to 1 that is the root should be more length here than the crown that is ideal it is optimal one is 1 is to 1 or ideal it is 2 is to 3 that is more root length then the root configuration the curved roots and the longer roots are preferred then the root support we need to take an IOPA and make sure that there is no periodical or periodontal problems then the periodontal ligamental area the perisemental area of the abutment should be greater than the teeth to be replaced and finally the assessment of pulpal health a tooth without any pulpal issues should be selected for an abutment. So it is small concept but usually questions came as a short notes the one is crown root ratio then the anti slow sometimes criteria of abutment selection in FPD. I will come up with a new topic in prosodontics thank you.