Effect of Calcium Hydroxide as an Intracanal Medication on Dentine Fracture Resistance: A Systematic Review and Network Meta-Analysis.

INTRODUCTION: Bacterial infections necessitate effective root canal disinfection during endodontic therapy. Calcium hydroxide (CH), a widely used intracanal medication, shows conflicting effects on dentine fracture resistance in different studies. This study aimed to perform a comprehensive systematic review and network meta-analysis to evaluate the effects of CH on the fracture resistance of dentine in human teeth across different periods. METHODS: PubMed, EMBASE, MEDLINE (EBSCO), Cochrane Library, Scopus, Google Scholar, and ProQuest databases were exhaustively searched to identify studies published until February 29, 2024, with no language restrictions. Laboratory studies that investigated dentine fracture resistance in human permanent teeth following intracanal CH exposure were included. The risk of bias was evaluated using modified criteria derived from previous studies. Network meta-analysis was performed using the frequentist method. Prespecified subgroup analyses focused on simulating immature teeth. RESULTS: The search yielded 2,265 studies from all databases, and 27 met the inclusion criteria, involving 3,879 teeth or roots. The overall results from network meta-analysis indicated that CH affected the fracture resistance of human dentine. Subgroup analysis revealed that the duration influencing fracture resistance was ≥4 weeks for mature teeth, but no specific time limitation for immature teeth. The overall quality of the evidence showed a moderate to high risk of bias. CONCLUSIONS: Short-term use of CH does not compromise human root dentine strength, supporting its routine application in clinical practice. CH remains a viable treatment strategy for over 4 weeks of medication needs but requires carefully considering the associated risks and benefits emphasizing on preservation and disease resolution. REGISTRATION: PROSPERO database (CRD 42024513199).

Mahidol Study 2: Treatment Outcomes and Prognostic Factors of Regenerative Endodontic Procedures in Immature Permanent Teeth.

INTRODUCTION: Studies on the clinical outcomes and prognostic factors of regenerative endodontic procedures (REPs) in a large population and long-term recall period have been limited. Therefore, the aims of this study were to evaluate treatment outcomes and prognostic factors of REPs. METHODS: Immature permanent teeth treated with REPs with a minimum one-year follow-up period were included. Treatment outcomes (functional retention, healed rate, root development, and sensibility test response) and any prognostic factors were analyzed with multivariable Cox regression, linear regression, and modified Poisson regression. RESULTS: One-hundred-twenty REPs teeth with a mean 41.7-month recall period were included with a functional retention rate of 97.5%. The healed, healing, and diseased rates of REPs were 80%, 9.2%, and 10.8%, respectively. Significant prognostic factors for healed were age (<12 years old) and root development stage (stages 4 and 5). Changes in the apical diameter, root length, root width, and radiographic root area after REPs were 56.8%, 8.3%, 23.2%, and 21.7%, respectively. Significant prognostic factors for continued root development were age and etiology of pulpal disease (from caries or dental anomalies). The sensibility test response rate was 41.7% with significant positive factors of ethylenediaminetetraacetic acid irrigation and capping material level above the cemento-enamel junction. CONCLUSION: REPs demonstrated high functional retention and healed rates. Patients <12 years old presented a higher healed rate and continued root development (excluding root length). Dental caries or anomalies had higher continued root development compared with dental trauma. The sensibility test response was related to ethylenediaminetetraacetic acid irrigation and level capping material.

Fracture resistance, gap and void formation in root-filled mandibular molars restored with bulk-fill resin composites and glass-ionomer cement base.

AIM: To evaluate fracture resistance and gap/void presence of root-filled mandibular molars restored with 2 bulk-fill and 1 conventional resin composites, with or without a glass-ionomer cement (GIC) base. METHODS: Coronal access and mesio-occlusal (MO) cavities were prepared, then root canal treatment was performed on 30 mol/L. The teeth were randomly divided, according to the cavity volume, into 6 experimental groups (N = 5) and restored with conventional/light-cured (Ceram-X), bulk-fill/light-cured (SureFil SDR) or bulk-fill/dual-cured (Core-X Flow) with/without a 2-mm thick GIC base. Gaps and voids (%) were determined using microcomputed tomography. Intact teeth and unrestored teeth were used as negative and positive controls. Fracture load (N) was determined using a universal testing machine. RESULTS: No significant difference in fracture resistance or gap/void formation was found among the 3 resin composites. GIC-base groups revealed significantly lower fracture strength than intact teeth, while fracture strengths of no GIC-base groups were not significantly different from intact teeth. GIC-base groups revealed significantly more gaps and voids in the area of the GIC than the resin composite. CONCLUSION: Conventional and bulk-fill resin composites provided similar fracture resistance and gaps/voids in root-filled molars with MO cavities. Placing a GIC base decreased fracture resistance and increased gap/void formation.

Root Reinforcement after Obturation with Calcium Silicate-based Sealer and Modified Gutta-percha Cone.

INTRODUCTION: A root canal obturated with a calcium silicate-based sealer (bioceramic sealer [BCS]) and a modified gutta-percha cone (bioceramic cone [BCC]) might improve the fracture resistance of the root. The objective of this study was to evaluate root reinforcement of a bioceramic cone/sealer (TotalFill; FKG Dentaire SA, La Chaux-de-Fonds, Switzerland) by investigating the fracture resistance, push-out bond strength, sealer penetration, and modulus of elasticity (MOE) in comparison with gutta-percha/AH Plus (Dentsply Maillefer, Tulsa, OK) (GP/AH). METHODS: Eighty-four roots from bilateral mandibular premolars were prepared. For fracture resistance, 40 teeth were randomly divided into 4 groups (n = 10 each): intact roots (negative control), prepared roots (positive control), and the roots obturated with either BCC/BCS or GP/AH. Root canals were obturated with the matched single-cone technique and vertically loaded with a spreaderlike tip until fracture. For push-out bond strength (n = 10 each), coronal, middle, and apical root slices of BCC/BCS and GP/AH were loaded with a cylindrical plunger, and failure modes were determined. Sealer penetration of BCC/BCS and GP/AH (n = 12 each) was evaluated for the maximum depth and the circumferential and total area of penetration at the coronal, middle, and apical levels using confocal laser scanning microscopy. The MOE was investigated according to ISO 4049:2000. RESULTS: The fracture load of BCC/BCS, GP/AH, and the intact roots was not significantly different but significantly higher than the prepared, nonobturated roots. BCC/BCS provided a higher bond strength, maximum depth, and circumferential penetration at the apical root level as well as a greater sealer penetration area at all levels compared with GP/AH. The MOE of all materials was much lower than dentin. CONCLUSIONS: BCC/BCS and GP/AH bonded and reinforced the prepared roots; their fracture resistances were similar to the intact roots.