Biomechanical effect of an occlusal device for patients with an implant-supported fixed dental prosthesis under parafunctional loading: A 3D finite element analysis.

STATEMENT OF PROBLEM: Whether providing an occlusal device for a patient with bruxism and an implant-supported fixed dental prosthesis leads to improved biomechanics is unclear. PURPOSE: The purpose of this 3D finite element analysis (FEA) study was to evaluate the biomechanical behavior of 3-unit implant-supported prostheses under parafunctional forces with and without an occlusal device. MATERIALS AND METHODS: Eight 3D models consisting of a posterior (type IV) maxillary bone block with 3 external hexagon implants (Ø4.0×7.0 mm) and 3-unit implant-supported prostheses with different crown connections (splinted or unsplinted) and an occlusal device under functional and parafunctional loading were simulated. The abutment screws were evaluated by von Mises stress maps, and the bone tissue by maximum principal stress and microstrain maps by using a finite element software program. RESULTS: An occlusal device improved the biomechanical behavior of the prostheses by reducing stress in the abutment screws and stress and strain in the bone tissue. However, the use of an occlusal device was not sufficiently effective to negate the biomechanical benefit of splinting. CONCLUSIONS: The use of splinted crowns in the posterior maxillary region with an occlusal device was the most effective method of reducing stress in the abutment screws and stress and strain in the bone tissue when parafunction was modeled.

Post-operative pain after using sodium hypochlorite and chlorhexidine as irrigation solutions in endodontics: Systematic review and meta-analysis of randomised clinical trials.

CONTEXT: Is it possible that the irrigating solutions can have the potential to cause post-operative pain? Unfortunately, the current literature does not provide clear guidance. AIM: The purpose of this systematic review and meta-analysis was to comprehensively review two different irrigation solutions (sodium hypochlorite and chlorhexidine) regarding the post-operative pain after endodontic treatment. SETTINGS AND DESIGN: This study was prepared according to the Cochrane criteria for creating a systematic review and meta-analysis and confirms the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. MATERIAL AND METHODS: This search was conducted in the PubMed/MEDLINE, SCOPUS and Cochrane Library databases until February 2018 to answer the In [(Population) what is the effect of (Intervention) on (Outcome), compared with (Comparison) Intervention] (PICO) question: could sodium hypochlorite cause more post-operative pain than chlorhexidine in teeth subjected to endodontic treatment? The primary outcome was overall post-operative pain after 24 h. RESULTS: After applying the inclusion and exclusion criteria, three randomized clinical trials fulfilled the eligibility criteria, and two were subjected to the meta-analysis. There was no difference in post-operative pain between the tested irrigating solutions. CONCLUSIONS: There are few studies published in the current literature; therefore, additional randomized clinical studies are required to on this topic to help clinicians make the best decision concerning treatment.

Interrelationship Between Periapical Lesion and Systemic Metabolic Disorders.

BACKGROUND: Periapical periodontitis, also known as periapical lesion, is a common dental disease, along with periodontitis (gum disease). Periapical periodontitis is a chronic inflammatory disease, caused by endodontic infection, and its development is regulated by the host immune/inflammatory response. Metabolic disorders, which are largely dependent on life style such as eating habits, have been interpreted as a "metabolically-triggered" low-grade systemic inflammation and may interact with periapical periodontitis by triggering immune modulation. The host immune system is therefore considered the common fundamental mechanism of both disease conditions. METHOD: We have reviewed >200 articles to discuss the interrelationship between periapical lesions and metabolic disorders including type 2 diabetes mellitus, hypertension, and non-alcoholic fatty liver diseases (NAFLD), and their common pathological background in immunology/osteoimmunology and cytokine biology. RESULTS: An elevated inflammatory state caused by metabolic disorders can impact the clinical outcome of periapical lesions and interfere with wound healing after endodontic treatment. Although additional well-designed clinical studies are needed, periapical lesions appear to affect insulin sensitivity and exacerbate non-alcoholic steatohepatitis. CONCLUSION: Immune regulatory cytokines produced by various cell types, including immune cells and adipose tissue, play an important role in this interrelationship.