1. Endo-perio interdependence
Does the periodontal status at the time of nonsurgical root canal treatment (NSRCT) affect the survival rate of endodontically treated teeth (ETT)? This retrospective investigation included 315 ETT molars with an acceptable quality of NSRCT; that received an adequate crown within three months after NSRCT; and had a complete periodontal charting before endodontic treatment including pocket depths, clinical attachment loss, and bone loss. Teeth that were diagnosed with mild periodontitis were almost two times more likely to be extracted compared with those diagnosed with normal periodontium at the time of NSRCT. This increased risk of tooth loss was 3.1 for teeth diagnosed with moderate periodontitis and smokers were twice as likely to have tooth loss compared with non-smokers. Patients' periodontal health, being one of the prognostic determinants of the outcome of nonsurgical endodontic treatment, requires attention before, and subsequent to, such intervention which may improve the survival of ETT and help patients maintain their natural dentition.

Khalighinejad N et al. The influence of periodontal status on endodontically treated teeth: 9-year survival analysis. J Endodontics 2017 Aug 16.

Q For which type of patients is the risk of tooth loss subsequent to nonsurgical endodontic treatment greatest?
A Smokers with moderate periodontitis
B Those with a normal periodontium
C Non-smokers with mild periodontitis
D All patient groups are equally at risk

  1. Diabetic patients scrutinised
The purpose of this prospective study was to compare the success of primary root canal treatment between type 2 diabetic and nondiabetic patients and to investigate the effect of periapical healing on glycated haemoglobin (HbA1c) in type 2 diabetic patients with apical periodontitis. The study included 60 mandibular molars with necrotic pulps and apical radiolucency and based on their HbA1c levels, patients were divided into two groups: type 2 diabetic (HbA1c >=6.5%) and nondiabetic (HbA1c <6.5%). Forty-six teeth were evaluated 12-months later. Both groups showed a significant reduction in the periapical score after a year but significantly less healing was observed in the diabetic group (43%) compared with the nondiabetic group (80%). HbA1c levels in the diabetic group increased at each follow-up after endodontic treatment. Diabetes mellitus may have a negative impact on the outcome of endodontic treatment in terms of periapical healing. Nonsurgical endodontic treatment did not improve HbA1c levels in patients with type 2 diabetes.

Arya S et al. Healing of apical periodontitis after nonsurgical treatment in patients with type 2 diabetes. J Endodontics 2017 Aug 10.

Q Diabetes mellitus
A May have a positive impact on endodontic treatment in terms of periapical healing
B Subjects in the test group showed progressive reduction of HbA1c levels
C May have a negative impact on endodontic treatment in terms of periapical healing
D Has neither a positive or negative influence on endodontic treatment outcomes

  1. Pain in the molars
The purpose of this systematic review and meta-analysis was to evaluate utilisation of supplementary techniques for pain control during root canal treatment of lower molars with irreversible pulpitis. The literature was searched using electronic databases up to the year 2012. Seventeen studies with 1,504 participants were included and each study compared experimental interventions with a standard treatment, i.e. the inferior alveolar nerve block. Changing the injection techniques or supplemental injection had no significant effect on pulp anaesthesia compared to the standard treatment, whereas changing anaesthetic features and increasing anaesthetic volumes resulted in significantly higher rates of anaesthesia than those of the standard treatment. Premedication with non-steroidal anti-inflammatory drugs (NSAIDs) also significantly increased the success rate of anaesthesia. Taken together, increased anaesthetic volumes and premedication with NSAIDs provide predictable anaesthesia and more pain control during endodontic treatment of lower molars with irreversible pulpitis.

Tupyota P et al. Supplementary techniques for pain control during root canal treatment of lower posterior teeth with irreversible pulpitis: A systematic review and meta-analysis.
Australian Endodontic J 2017 Jul 24.

Q Based on this research what action would you take to minimise pain during root canal treatment of lower molars with irreversible pulpitis?
A Use only topical anaesthetic
B Advise no premedication and give supplemental injections
C Give supplemental injections and premedicate with NSAIDs
D Premedicate with (NSAIDs) and use increased anaesthetic volumes

  1. Which technique sticks best?
This study evaluated the substantivity of chlorhexidine (CHX) to dentine using manual, rotary, and reciprocating systems for root canal preparation using 45 extracted human single-rooted teeth. Three equal groups were formed: manual instrumentation (K-File), rotary instrumentation (ProTaper), and reciprocating instrumentation (Reciproc R25). Chlorhexidine gel (2%) was used as an auxiliary chemical substance during root canal preparation. Longitudinal grooves were carved on the free surfaces of the roots, providing two halves of each root and resulting in 30 samples per group. Each group was randomly divided into three subgroups and substantivity was evaluated after 48 h, 7 days, and 30 days of incubation. The manual technique did not show a statistically significant difference compared to rotary instrumentation, but higher CHX substantivity was recorded in all periods of observation when compared to reciprocating instrumentation. The CHX substantivity on human dentine is lowest when using reciprocating compared to manual and rotary instrumentation.

Souza MA. Effect of root canal preparation techniques on chlorhexidine substantivity on human dentin: a chemical analysis. Clin Oral Investig 2017 Jul 01.

Q Chlorhexidine substantivity to dentine:
A Is a measure of how well the substance is repelled by dentine
B Can be increased by use of reciprocating endodontic equipment
C Is increased by using either manual or rotary instrumentation
D Remains unaffected by the endodontic technique