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Dental implants

Is there an advantage to delayed molar implant placement in those with chronic apical periodontitis?



This paper is a single-centre, double-blinded, prospective randomised control trial, comparing immediate vs delayed implant placement clinically and radiographically in patients with chronic periodontitis, specifically assessing the molar region. Seventy-four patients were recruited to the study over a one-year period, all of whom returned for follow up throughout the study.

Study selection

The study adhered to the principles outlined in the Declaration of Helsinki and obtained ethical approval from the affiliated University Hospital of Qingdao. Written consent was gained from patients in line with the CONSORT guidance. The patients were recruited from the Department of Oral and Maxillofacial Surgery at the University of Qingdao between January 2019 and January 2020. The study included anyone above the age of 18, who had a molar with chronic apical periodontitis and lesions of less than 8 mm. Exclusions included pregnancy, uncontrolled diabetes, smokers, bisphosphonate use, history of head/neck tumours, coagulation disorders, and acute infections of adjacent teeth/tissue.

Data extraction and synthesis

Of the patients who met the inclusion criteria, all were randomly numbered by a stomatologist and placed into either the control group or the experimental group by a computerised system (Microsoft Excel). This study looked at the placement of 74 implants in 74 patients, including 40 female and 34 male patients in total. The delayed implant placement allowed for healing of 3 months in the mandible and 6 months in the maxilla. The width of the implants placed was 6 mm and the lengths were between 7 mm and 12 mm. The periodontal probing depth, modified sulcus bleeding index, and modified plaque index were all clinically examined. In terms of other parameters assessed, CBCT was used to look at alveolar bone mass. All surgery and implant placement was carried out by the same surgeon and the clinical measurements were all taken by one dentist.


The results showed no significant difference in implant stability quotient immediately and 6 months post-surgery (0.110 and 0.066, respectively), when comparing the experimental and control group. Similarly, there was no significant difference in PD, mSBI or mPI between the groups. On assessment of CBCT scans however there was a significant difference between the two groups in the buccal horizontal marginal bone loss (P = 0.003), lingually there was not. Vertical bone loss also showed no significant difference in comparison. At one-year post-implant placement, there was a survival rate of 100% in both groups assessed. IBM SPSS statistics was used for statistical analysis. Multiple tests including the Shapirowilk test, the student t-test and the Mann-Whitney U-test were carried out on the data and all statistical tests were two tailed. Statistical significance was set at <0.05 throughout study of results.


The conclusion of this study suggests that immediate implant placement in chronic periodontitis patients, specifically in the molar region, may be clinically viable. With flap surgery and complete removal of inflammatory granulation tissue, the study suggests no significant disadvantage to alveolar bone healing or osseointegration. The various limiting factors of this study should be taken into consideration, and it must be highlighted that longer and larger studies are necessary to allow for more accurate understanding of the long-term outcomes.

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Correspondence to Rabab Ahmad.

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Ahmad, R. Is there an advantage to delayed molar implant placement in those with chronic apical periodontitis?. Evid Based Dent 25, 79–80 (2024).

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