{"id":36,"date":"2023-05-22T13:37:08","date_gmt":"2023-05-22T13:37:08","guid":{"rendered":"https:\/\/ekitap.ankara.edu.tr\/dentures\/chapter\/destek-dislerin-ark-uzerindeki-konum-ve-sayilarina-gore-fulkrum-eksenleri\/"},"modified":"2025-10-31T09:26:43","modified_gmt":"2025-10-31T09:26:43","slug":"destek-dislerin-ark-uzerindeki-konum-ve-sayilarina-gore-fulkrum-eksenleri","status":"publish","type":"chapter","link":"https:\/\/ekitap.ankara.edu.tr\/dentures\/chapter\/destek-dislerin-ark-uzerindeki-konum-ve-sayilarina-gore-fulkrum-eksenleri\/","title":{"raw":"Fulcrum lines according to the position and number of abutment teeth on the dental arch","rendered":"Fulcrum lines according to the position and number of abutment teeth on the dental arch"},"content":{"raw":"When only a single abutment tooth is present, numerous radial<\/strong> or rotational fulcrum lines may develop. This results in excessive mobility of the prosthesis, making single-tooth-supported removable partial dentures an unfavorable option.\r\n\r\nWhen the remaining teeth are located on one side of the arch, a unilateral asymmetric<\/strong> fulcrum line is established. Due to the unequal abutment teeth location on both sides of the arch, this results in increased mobility of the prosthesis.\r\n\r\nA bilateral diametric<\/strong> fulcrum line is established between two terminal abutment teeth positioned symmetrically on both sides of the arch. This configuration is more advantageous compared to the previous two scenarios.\r\n\r\nBetween two primary abutment teeth positioned asymmetrically on either side of the arch, a bilateral diagonal<\/strong> fulcrum line develops, and this configuration is once again better than the first two in terms of prosthesis movement (Figure 1-12).\r\n\r\n \r\n\r\n[caption id=\"attachment_1065\" align=\"alignnone\" width=\"300\"]\"Figure Figure 1-12.<\/strong> Fulcrum lines based on the position and number of abutment teeth on the arch.[\/caption]\r\n\r\nWhen the number of primary abutment teeth exceeds two, a sustentation plane, rather than a fulcrum line, is generated, and this configuration improves the retention and stability of the prosthesis (Figure 1-13).\r\n\r\n
\r\n[pbcaption type=\"image\" caption=\"Figure 1-13.<\/strong> Sustentation planes based on the position and number of terminal abutment teeth on the arch.\"]\r\n\r\n[caption id=\"attachment_1070\" align=\"alignleft\" width=\"300\"]\"Triangular\" \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 Triangular<\/strong>[\/caption]\r\n\r\n[caption id=\"attachment_1072\" align=\"alignnone\" width=\"300\"]\"Quadrangular\" \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 Quadrangular<\/strong>[\/caption]\r\n\r\n[\/pbcaption]\r\n
\r\n\r\nA triangular sustentation plane<\/strong> is developed between three abutment teeth positioned on both sides of the arch. However, in the presence of distal extension denture base, there is always the possibility of rotation around the fulcrum line formed between the primary abutments\u2014one adjacent to the distal extension denture base and the other located most posteriorly on the opposite arch.\r\n\r\nWhen four symmetrically positioned abutment teeth are present on both sides of the dental arch, a quadrangular sustentation plane<\/strong> is developed, and this typically applies to Kennedy Class III cases with a posterior modification.","rendered":"

When only a single abutment tooth is present, numerous radial<\/strong> or rotational fulcrum lines may develop. This results in excessive mobility of the prosthesis, making single-tooth-supported removable partial dentures an unfavorable option.<\/p>\n

When the remaining teeth are located on one side of the arch, a unilateral asymmetric<\/strong> fulcrum line is established. Due to the unequal abutment teeth location on both sides of the arch, this results in increased mobility of the prosthesis.<\/p>\n

A bilateral diametric<\/strong> fulcrum line is established between two terminal abutment teeth positioned symmetrically on both sides of the arch. This configuration is more advantageous compared to the previous two scenarios.<\/p>\n

Between two primary abutment teeth positioned asymmetrically on either side of the arch, a bilateral diagonal<\/strong> fulcrum line develops, and this configuration is once again better than the first two in terms of prosthesis movement (Figure 1-12).<\/p>\n

 <\/p>\n

\"Figure
Figure 1-12.<\/strong> Fulcrum lines based on the position and number of abutment teeth on the arch.<\/figcaption><\/figure>\n

When the number of primary abutment teeth exceeds two, a sustentation plane, rather than a fulcrum line, is generated, and this configuration improves the retention and stability of the prosthesis (Figure 1-13).<\/p>\n

\n
\n
\"Triangular\"
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 Triangular<\/strong><\/figcaption><\/figure>\n
\"Quadrangular\"
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 Quadrangular<\/strong><\/figcaption><\/figure>
Figure 1-13.<\/strong> Sustentation planes based on the position and number of terminal abutment teeth on the arch.<\/figcaption><\/figure>\n
\n

A triangular sustentation plane<\/strong> is developed between three abutment teeth positioned on both sides of the arch. However, in the presence of distal extension denture base, there is always the possibility of rotation around the fulcrum line formed between the primary abutments\u2014one adjacent to the distal extension denture base and the other located most posteriorly on the opposite arch.<\/p>\n

When four symmetrically positioned abutment teeth are present on both sides of the dental arch, a quadrangular sustentation plane<\/strong> is developed, and this typically applies to Kennedy Class III cases with a posterior modification.<\/p>\n","protected":false},"author":3,"menu_order":4,"template":"","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_uf_show_specific_survey":0,"_uf_disable_surveys":false,"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-36","chapter","type-chapter","status-publish","hentry"],"part":21,"_links":{"self":[{"href":"https:\/\/ekitap.ankara.edu.tr\/dentures\/wp-json\/pressbooks\/v2\/chapters\/36","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ekitap.ankara.edu.tr\/dentures\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/ekitap.ankara.edu.tr\/dentures\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/ekitap.ankara.edu.tr\/dentures\/wp-json\/wp\/v2\/users\/3"}],"version-history":[{"count":25,"href":"https:\/\/ekitap.ankara.edu.tr\/dentures\/wp-json\/pressbooks\/v2\/chapters\/36\/revisions"}],"predecessor-version":[{"id":1923,"href":"https:\/\/ekitap.ankara.edu.tr\/dentures\/wp-json\/pressbooks\/v2\/chapters\/36\/revisions\/1923"}],"part":[{"href":"https:\/\/ekitap.ankara.edu.tr\/dentures\/wp-json\/pressbooks\/v2\/parts\/21"}],"metadata":[{"href":"https:\/\/ekitap.ankara.edu.tr\/dentures\/wp-json\/pressbooks\/v2\/chapters\/36\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/ekitap.ankara.edu.tr\/dentures\/wp-json\/wp\/v2\/media?parent=36"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/ekitap.ankara.edu.tr\/dentures\/wp-json\/pressbooks\/v2\/chapter-type?post=36"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/ekitap.ankara.edu.tr\/dentures\/wp-json\/wp\/v2\/contributor?post=36"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/ekitap.ankara.edu.tr\/dentures\/wp-json\/wp\/v2\/license?post=36"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}