The use of periapical radiography and cone beam computed tomography for assessment of the periapical tissues after endodontic treatment

The aim of this clinical study is to compare the radiographic changes in periapical status of individual roots by using periapical radiographs and cone beam computed tomography (CBCT) after 18 months of root canal treatment.Diagnostic digital periapical radiographs and CBCT scans were taken of 86 teeth requiring root canal treatment in 42 patients that fulfilled the clinical and radiological inclusion criterias (PAI ? 3). The patients were re-evaluated 18 months post-operatively. The presence or absence as well as increase or decrease in the size of existing periapical radiolucency was assessed by three calibrated examiners. The results are assessed by using McNemar?s statistical analysis. The periapical index (PAI), CBCTPAI scores and whole score systems correlations were determined by Spearman's rho test.The ratio of `resolved lesions? in periapical radiography assessment was 44.19%, whereas the same ratio in CBCT evaluation was 26.74%. There was a statistically significant difference between diagnostic techniques (p<0.05). This rate increased to 95.35% and 93.02% respectively for `effective treatment? groups (reduced size of periapical radiolucency) at the end of the follow up period. The lesions were re-assessed in follow up period and categorized as `presence or absence of a lesion?. There was statistically significant difference between these two groups (p<0.05). The PAI and CBCTPAI score results are categorized as `resolved?, `reduced?, `unchanged? and `enlarged? lesions and evaluated statistically. There was a statistically significant difference between these groups (p<0.05). Lesions were re-grouped as `absence or presence? of a lesion in PAI and CBCTPAI groups. There was statistically significant difference between those groups respectively (p<0.05).In conclusion; diagnostic results in CBCT group revealed a lower `reduced? and `resolved? rate for primary root canal treatment than periapical radiographs. The millimetric measurements of the lesions, PAI and CBCT score systems had similar correlations at first; however the similarity between score systems reduced in time.