The Influence of an Isthmus on the Outcomes of Surgically Treated Molars: A Retrospective Study

By Sunil Kim, Hoiin Jung, Sooyun Kim Su-Jung Shin and Euiseong Kim

Date: 11/2016
Journal: JOE

Purpose: To investigate the effects of an isthmus on the outcomes of surgically treated molars.

N= 106 Maxillary and mandibular 1st molars (72 with isthmus, 34 without)  with endodontic lesion limited to periapical area.

•Surgical procedures were performed by the same operator

•Isthmus was included in the retrograde preparation design when observed and filled with either ProRoot MTA or Super EBA

. •Patients were followed up once a year after treatment (for 4 years).

Success was defined as: the absence of clinical signs and symptoms and radiographic evidence of complete or incomplete healing (2 blinded examiners evaluated the periapical radiographs).

Most highlighted Results:

 – The cumulative survival rate after surgery was 61.5% for 4 years when an isthmus was present and prepared. The survival rate after 4 years was 87.4% when an isthmus was absent and unprepared.

Clinical significance:

•Success rate for endodontic microsurgery on isthmus-absent teeth was higher than that for isthmus-present teeth.

•The technique of isthmus retrograde-preparation needs to be improved and carried out carefully.