Endodontic-periodontal lesions: microbiome and treatment outcomes

Faculty of Dentistry, Oral & Craniofacial Sciences

First supervisor: Dr Sadia Niazi

First co-supervisor: Dr Emily Lu

Second supervisor: Dr David Moyes

Mode of study: Full-time

Duration: 3 years

Start date: June 2025

Application deadline: 20 March 2025 for Overseas fee status and 11 April 2025 for Home fee status

Applications are welcomed from self-funded students or sponsored students, both Home and Overseas.

Students will need to self-fund or gain sponsorship for clinical PhD annual fees shown at this page plus bench fees of £10,000 per year.

Reference number: 2024/DOCS/SN

Project description

Endodontic-periodontal disease has been characterized by the involvement of the pulp and periodontal diseases in the same tooth. The anatomic connections between the dental pulp and the periodontium provide pathways for perio-endo communication which result in the clinical presentation of the disease.

Primary periodontal /secondary endodontic lesions and true combined lesions are challenging since the clinical outcome of these is significantly less predictable than that of those arising due to primary endo disease and require multidisciplinary management involving endodontic treatment in the form of root canal treatment followed by staged periodontal treatment (McGuire et al., 1996; Abbott et al., 2009).

The root canal treatment involves cleaning and disinfection of the tooth root canal system where infection is present. This is followed by filling of the tooth root canal with root filling materials (Salehrabi et al., 2004, Setzer et al., 2011). Lately, some biocompatible sealers (hydraulic calcium silicate sealers) have been used for root canal treatments have shown good results (Zavattini et al., 2020). A non-randomized clinical trial comparing the effects of BioRoot^TM RCS and conventional resin-based sealer - AH Plus sealer (Dentsply, Germany)] reported a higher success rate BioRoot^TM RCS compared to AH Plus sealer (Zavattini et al., 2020). Furthermore, previous study comparing antimicrobial efficacy of calcium silicate sealers (BioRoot RCS and Total Fill BC) and conventional sealers (AH Plus and Tubli-seal) demonstrated that BioRoot RCS had superior biofilm inhibition capacity and microbial killing, with strong alkalizing activity compared to conventional sealers (Bose et al., 2020)

The gold standard treatment for Periodontitis-affected teeth associated with intrabony lesions (vertical pattern of bone loss) is guided tissue regeneration (GTR) which has significantly improved clinical outcomes compared to open flap debridement (Bashutski et al., 2009; Cortellini et al., 2011, Needleman et al., 2000, Oh et al., 2009). However, the success of this regenerative technique requires careful case and defect and patient selection. We propose the use of an autologous bioactive scaffold, platelet rich fibrin (PRF), to achieve regeneration of periodontal soft and hard tissues, resulting in faster healing, greater bone infill and improved predictability of clinical outcomes. Platelet rich fibrin (PRF) is derived from blood drawn from patients. This consists of a rich mix of platelets, growth factors and stem cells which can encourage wound healing process (Choukroun et al., 2006). To our knowledge, no randomised controlled trial has been conducted examining the additional benefits of PRF when used in conjunction with GTR in the treatment of intrabony defects that is commonly observed in teeth associated with endodontic-periodontal lesions (EPL). Therefore, we hypothesise that the regenerative treatment of intrabony defects associated with EPL, by GTR in conjunction with PRF would results in superior clinical outcomes compared to GTR alone.

We have previously also investigated the microbiome of endodontic infections using targeted 16SrRNA gene and house-keeping gene sequence analysis, we determined the predominant cultivable microbiota of primary (Niazi et al., 2016) and secondary (failed) Endodontic infections (Niazi et al., 2010). We have lately investigated the microbiome of root canal infections using next generation sequencing targeting region V1-V2 of 16SrRNA gene. We are also currently investigating the host microbiome interactions in these conditions. Although Endodontic periodontal disease differs in pathogenicity, but they do share common microbial factors and inflammatory mediators.

Therefore, this study is designed to address the following questions:

1) Is the outcome of combined Endodontic- periodontal disease managed by root canal treatment using Hydraulic calcium silicate sealer and guided tissue regeneration (GTR) with adjunctive use of PRF superior compared to the above treatment with GTR alone?

2) Are there any diagnostic or prognostic biomarkers (inflammatory markers or microbes) associated with the Endodontic- periodontal disease?

Person specification

Dentist or Endodontist or Periodontist
Research commitment
Previous research experience

Research training

To commence this project, the student will be trained on “Good Clinical Practice for Research for carrying out non-CTIMP studies” and “Human Tissue Act & Consent training” by attending courses provided by King's College London and King’s Health Partners. The student will also be obtaining training in PRF, which will be needed during patient management. This will enable them to collect/handle samples from study participants from the Periodontics and Prosthodontics Departments of Guy’s Hospital. While working in the Host Microbiome laboratories, the student will learn a range of molecular techniques including Elisa, Multiplex Luminex etc. They will also develop analytical skills using different software including “SPSS”, “R” etc. This research training will enhance their scientific writing and presentation skills. During the PhD they will also have access to numerous courses available for development of postgraduate students.

To view entry requirements and further general information, see the Dental and Health Sciences Research MPhil/PhD prospectus page.

Next steps and contact for further information

Applicants are strongly encouraged to discuss the project with the first supervisor prior to submitting an application.

Please apply online at apply.kcl.ac.uk following these steps:

Register a new account/login.
Once logged in, select Create a new application.
Enter ‘Dental and Health Sciences Research MPhil/PhD (Full-time)/(Part-time)' under Choose a programme. Please ensure you select the correct mode of study.
Select a start date from the list.
Please note: Applicants must include the project reference number (2024/DOCS/SN) in the 'Research proposal' and 'Funding (point 5)' sections of the application.